What is a Seamless Steel Pipe?
Seamless steel pipes are perforated from whole round steel, and steel pipes without welds on the surface are called seamless steel pipes. According to the production method, seamless steel pipes can be divided into hot-rolled seamless steel pipes, cold-rolled seamless steel pipes, cold-drawn seamless steel pipes, extruded seamless steel pipes, and top pipes. According to the cross-sectional shape, seamless steel pipes are divided into two types: round and special-shaped. Special-shaped pipes include square, oval, triangular, hexagonal, melon seed, star, and finned pipes. The maximum diameter is 900mm and the minimum diameter is 4mm. According to different purposes, there are thick-walled seamless steel pipes and thin-walled seamless steel pipes. Seamless steel pipes are mainly used as petroleum geological drilling pipes, cracking pipes for petrochemical industry, boiler pipes, bearing pipes, and high-precision structural steel pipes for automobiles, tractors, and aviation.

API seamless pipe have a hollow section and are used in large quantities as pipelines for transporting fluids, such as pipelines for transporting oil, natural gas, gas, water and certain solid materials. Compared with solid steel such as round steel, steel pipe is lighter in flexural and torsional strength and is an economical section steel. Widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes, automobile transmission shafts, bicycle frames, and steel scaffolding used in construction. Steel pipes are used to make ring parts, which can improve material utilization, simplify manufacturing procedures, and save materials and processing. Working hours.

A seamless steel pipe is a circular pipe having a hollow section and no seams around it. The ASTM seamless pipe is made of carbon steel, alloy steel, stainless steel ingot or solid tube blank, and then is made by hot rolling, cold rolling or cold drawing. Seamless pipes are considered superior to welded pipes as they are built using monolithic steel billets, with intrinsic mechanical strength, without seam welds.

What is a seamless steel pipe?
A seamless steel pipe is a circular pipe having a hollow section and no seams around it. The seamless steel pipe is made of carbon steel, alloy steel, stainless steel ingot or solid tube blank, and then is made by hot rolling, cold rolling or cold drawing. Seamless pipes are considered superior to welded pipes as they are built using monolithic steel billets, with intrinsic mechanical strength, without seam welds.

Characteristics of seamless steel pipe
Seamless steel pipe for the use of engineering and construction is very widely, it is a hollow steel strip no seams, it is mainly used to transport liquids pipelines, different look and general steel,one of those heavy type steel, it has a strong resistance to corrosion, resistant to general corrosion.
Will not rust, this performance makes seamless steel tubes extend the life, the most important is that it is very clean and no toxins.
Compared with other plastic seamless steel pipe having strong mechanical resistance, impact regardless of how high a temperature is not interested in the use of seamless steel pipe, it is mounted and the other pipe is the same, can replace other piped water and other liquids. 

Since the industrial applications have become complex and evolved a lot, the piping products are also changing to stay in the race. Although there are many pipe processing techniques, the industry's most influential controversy between electrical resistance welded and spiral steel pipe. 

As they are produced, some seamless pipe types harden, so heat treatment after production is not needed. Others need thermal therapy. Consult the seamless pipe form specification you are considering to learn if heat treatment would be needed.

As alternatives today, ERW and seamless steel piping remain primarily due to historical beliefs.

Generally, since a weld seam was used, the welded pipe was deemed inherently weaker. This supposed design weakness was absent from the seamless pipe and was deemed safer. Although it is true that welded pipe has a seam that makes it technically weaker, manufacturing processes and quality assurance regimes have all advanced to the degree that when its tolerances are not exceeded, welded pipe can work as expected. While the obvious benefit is apparent, a criticism of seamless piping is that, compared to the more reliable thickness of steel sheets intended for welding, the rolling and stretching process creates an inconsistent wall thickness.

These perceptions are still expressed by the industry standards that regulate the production and specification of ERW and seamless steel pipes. For example, for many high-pressure, high-temperature applications in the oil & gas, power generation and pharmaceutical industries, seamless piping is needed. Welded piping (which is typically cheaper to manufacture and is more commonly available) is defined in all industries as long as the parameters noted in the relevant specification do not exceed the temperature, pressure and other service variables.

There's no difference in efficiency between ERW and pile pipe in structural applications. Although the two can be interchangeably defined, since cheaper welded pipe works just as well, it does not make sense to specify for seamless.

Healthy welded and seamless steel pipe buying procedure
As piping products are listed for a project, an important note to be made is that the specification books (such as those supplied by ASTM, ASME, ANSI and API, among others) that engineers use to direct the specifications they write only list pipe grades exclusive of referencing whether they are generated through ERW or seamless pipe production. By both ways, not all grades can be made.

For example, if an engineer defines welded pipes with a wide outside diameter and wall thickness without understanding that it would be difficult to produce them, a potential mix-up could occur. Until a purchase order is placed, this mistake would possibly go unnoticed, at which point an industrial pipe supplier would tell the customer that the order could not be fulfilled as written. See us at International Pipe Suppliers for the supply.

The development of numerical simulations is potentially useful in predicting the most suitable manufacturing processes and ultimately improving product quality. Seamless pipes are manufactured by a rotary piercing process in which round billets (workpiece) are fed between two rolls and pierced by a stationary plug. During this process, the material undergoes severe deformation which renders it impractical to be modelled and analysed with conventional finite element methods. In this paper, three-dimensional numerical simulations of the piercing process are performed with an arbitrary Lagrangian–Eulerian (ALE) formulation in LS-DYNA software. Details about the material model as well as the elements’ formulations are elaborated here, and mesh sensitivity analysis was performed. The results of the numerical simulations are in good agreement with experimental data found in the literature and the validity of the analysis method is confirmed. The effects of varying workpiece velocity, process temperature, and wall thickness on the maximum stress levels of the product material/pipes are investigated by performing simulations of sixty scenarios. Three-dimensional surface plots are generated which can be utilized to predict the maximum stress value at any given combination of the three parameters.

Metal pipes are categorized into welded pipes and seamless pipes. Welded pipes are commonly manufactured by bending and welding metal sheets, while seamless pipes are produced using the rotary piercing process. It is well recognized that seamless pipe provides more benefits than welded pipe, such as (1) increased pressure ratings; (2) uniformity of geometry, material properties, and matter; and (3) structural strength and fatigue capacities under load. Offshore industry especially requires over 30–40 years of design life and robust design of the piping system, pipeline, and riser structures are requested by adopting reliable materials, manufacturing processes, installation, and operation. Many benefits of seamless pipe, i.e., uniformity of shape and fatigue and strength capacity, allow for higher safety during the operation period of offshore pipeline [1,2,3] and riser structures [4,5,6] from repeated environmental loadings [7,8].
In the rotary piercing process, a heated round billet is fed into a plug by the action of two skewed rolls which rotate in the same direction. The rolls are tilted and placed on opposite sides of the workpiece, providing both rotation and translation to the workpiece. As mentioned by Komori [9], the rolls can be barrel-shaped or cone-shaped. Since the invention of the piercing process over a century ago, numerous empirical and analytical studies have been conducted and one of the good reviews have been conducted by Komori and Mizuno [10]. Experimental studies on cone-shaped-type rotary piercing using lead and wax were performed and a comparison was drawn between two-roll and three-roll cone systems. It was shown that the three-roll cone systems are superior to that of two-roll systems by Khudeyer et al. [11]. The effects of varying the feed angle on the shear strain were studied experimentally using hot steel. Hayashi and Yamakawa [12] found that with larger cross angles, the decrease in the circumferential shear strain is more significant. Moon et al. [13] and Sutcliffe and Rayner [14] conducted experimental work on the rolling process using modelling clay (Plasticine) due to the similarities of its stress–strain behaviour with that of metals and because of its malleability and low cost.
Finite element analysis (FEA) of metal forming processes was further performed to gather the necessary information to design and control these processes properly. In addition, the number of experimental trials can be minimized through the exploitation of FEA, which would significantly reduce the product development lead time. Moreover, with the decrease of experimental work, the overall development cost of the product would be reduced. Nowadays, the advancement of powerful computer technology enables the numerical simulations to consider various physical phenomena during metal processing which include deformation, heat transfer, phase transformation, and ductile fracture [15,16,17].
A two-dimensional rigid-plastic finite element simulation of rotary piercing was performed by Mori et al. [18]. However, the accuracy of the results was low since generalized plane strain was assumed from the simulation. Three-dimensional rigid-plastic finite element analysis was performed by Komori [9]. The number of the elements was limited, and the mesh was relatively coarse because large amounts of computational time were required. Berazategui et al. [19] used the pseudo-concentrations technique to conduct three-dimensional rigid-viscoplastic finite element simulations and a new algorithm was proposed to describe the contact boundary conditions between the tools and the blank. The algorithm was validated with industrial tests of the barrel-type rotary piercing process. However, the numerical analysis of the process was found to be complicated and the computational cost was rather large. Thus, an alternative simplified method was highly required [10]. Shim et al. [20] used a rigid-thermo-viscoplastic finite element method and conducted simulations with AFDEX 3D software to predict the final shape in better detail. Intelligent re-meshing and tetrahedral elements were used which resulted in increased computational cost. The same method was then used to conduct numerical studies on the Mannesmann effect in the piercing process, as well as to compare between the Diescher’s guiding disk and Stiefel’s guiding shoe [21,22].
Lee et al. [23] presented a novel method for adaptive tetrahedral element generation for precision simulation of moving boundary problems such as bulk metal forming. The effects of using tetrahedral solid elements were investigated in a three-dimensional simulation of the forging process with an AFDEX 3D forging simulator. The predictions of both tetrahedral and standard hexahedral elements were in good agreement with experimental data provided that the remeshing technique is employed by Lee et al. [24]. Pater and Kazanacki [25] used Simufact Forming software to analyze the effects of the plug diameter, plug advance, and feed angle on the piercing process. The influence of different plug shapes was further investigated by Skripalenko et al. [26]. ProCAST and QForm commercial software were used for the numerical simulation of piercing aluminium alloy. Jung et al. [27] conducted 3D numerical simulations on the elongation rolling process to study how the rolling speed (rpm) and distance of guide shoes influenced the outer diameter and thickness of the pipe. MSC-SuperForm software was used and an automatic re-meshing method of hexagonal elements was implemented. Xiong et al. [28] used the reproducing kernel particle method for the steady and non-steady analysis of bulk-forming processes and validated the numerical predictions with experimental measurements. Topa and Shah [29] performed 3D numerical simulations for a forging process with a complex tool geometry using the smooth particle hydrodynamics (SPH) method. The results were in fair agreement with experimental data, but the method had a poor visual representation of the final geometry. Hah and Youn [30] presented an effective Eulerian approach for bulk metal forming based on representing boundaries as non-uniform rational B-spline (NURBS) and the effectiveness of the proposed approach was demonstrated by comparing with other numerical methods. However, this approach had the drawback of a blurred boundary condition imposition.

The tools are assumed to be rigid parts as their deformation is insignificant and out of the scope in the current study. They are modelled with shell elements to minimize computational cost. Material model 24 (Piecewise Linear Plasticity) was used to model the Plasticine material behaviour. In this model, the stress–strain curve of the material can be imported to the keyword file to define the relationship between stress and strain. Multiple curves at different strain rates can be used to take into consideration the strain rates’ effects via the stress yield scaling method. Large deformation will cause an increase in the temperature and thermal softening. However, due to the high velocity of the process, it was assumed that changes to temperature were minimal and there was insufficient time for heat transfer to occur between the workpiece and the tools. Thus, the process is simplified to an isothermal system.

What Do We Know So Far on Hair Straightening?
Hair represents a valued aspect of human individuality. The possibility of having an easy to handle hairstyle and changing it from time to time promoted an increasing search for chemical hair transformations, including hair straightening. Hair straightening is the process used to convert curly into straight hair. The desire for straight hair used to be associated with the standards of the “universal beauty.” Currently, the preference for this style is more for the ease of handling and the simpler daily care routine [1]. Straightening may be physical or chemical processes and temporary or permanent, regarding its duration.

We performed a literature search in the scientific database MEDLINE through PubMed until July 15, 2020, using the terms “straightening” AND “hair” (125 results), “straightening” AND “alopecia” (22 results), and “straightening” AND “human hair” (103 results). We limited the search to articles available in English and considered those mentioning alternatives to straighten the hair. After excluding duplicate titles, we had a total of 33 relevant articles.

Anatomically, the hair shaft has 3 layers: cuticle, cortex, and medulla [2, 3]. The outermost part is the cuticle, which is composed of keratin and consists of layers of scales overlapping 1 and other, just like tiles on a roof. The cuticle protects the underlying cortex and acts as a barrier [3-5]. The normal, undamaged cuticle has 6–8 layers according to the ethnicity, a smooth surface, allowing reflection of light and limiting friction between shafts [5]. The outer surface of the cuticle’s scale cells is coated by a thin membrane, the epicuticle, and each cuticle cell consists of 3 layers of protein: the A-layer, a resistant layer with high cystine content; the exocuticle, also rich in cystine; and the endocuticle, low in cystine content. The cortex accounts for most of the hair shaft and is responsible for the hair. The cortex is comprised of microfibrils, long filaments oriented parallel to the axis of the fiber. Each microfibril consists of keratin intermediate filaments, also known as microfibrils, and the matrix, constituted by keratin-associated proteins [4]. It is the thickest layer located around the medulla, which is the innermost part of the hair, has melanin granules which composition is related to the shades of hair color. It is also responsible for hair volume, the great tensile strength, and mechanical resistance of the shaft, as it contains the most part of keratin [3-5].

The primary component of the hair fiber is keratin. The remaining constituents are represented by other proteins, water, lipids, pigments, and trace elements. Because of its specific conformation and chemical bonds, keratin is responsible for hair stiffness, strength, and insolubility. Among the amino acids that make up keratin, cystine is one of the most important. Each cystine unit contains 2 cysteine amino acids from different portions of the peptide chains that are connected by 2 sulfur atoms, forming a strong bond named disulfide bridge [3-5]. Another important structural component of the hair shaft is the 18-methyl eicosanoic (18-MEA) acid. It forms a hydrophobic layer that retards water from wetting and penetrating and changing the hair shaft physical’s properties. Removal of the fatty acid layer decreases the brightness of the hair, making it more susceptible to static electricity and frizzing induced by humidity [4].

The spiral shape of the hair is determined by the asymmetric protein expression in the hair follicles [2]. As it is not possible yet to modify the shape of the follicle, the only way to change hair appearance is by modifying its physicochemical properties [6].

This method was developed in the late 19th century and became popular in the early 20th century by Madame C.J. Walker, who combined hot comb with pressing oil. It is a temporary straightening since it changes only weak hydrogen bonds, in a process named keratin hydrolysis. The initial technique was the application of a petrolatum ointment base in the hair, followed by straightening it using a heated metal combing device. Over time, the technique was improved. However, with the introduction of new methods, the hot comb went out of use [1, 5, 7, 8].

Physicochemical techniques combining mechanical and thermal straightening, as hairdryer and flat iron, are temporary solutions that last until the next washing. The hair needs to be wet, so hydrogen bridges break and there is the transitional opening of the helical structure of the shaft, relaxing it. The combined use of the dryer and the flat iron dehydrates the hair, keeping it straight [1].

High temperatures, between 235 and 250°C in the dry hair and 155–160°C in the wet hair, may denature hair shaft proteins [1, 9]. Usually, hairdryers are more harmful to the hair shaft than naturally drying it [9]. However, a study showed that the use of the dryer with continuous movement, at a minimum distance of 15 cm from the hair, could be less damaging than natural drying [10].

Hydroxides are potent alkalis, widely used for straightening very curly hairs [11]. The primary substances of this group and their characteristics are described in Table 1. Sodium hydroxide, also known as lye, is indicated for straightening extremely curly hair. No-lye relaxers, such as guanidine hydroxide, are indicated for straightening wavy to curly hair and for sensitive scalp. Although milder for the scalp, it leaves calcium mineral residues on the hair shaft, making it drier, brittle, and dull [4, 11-14].

STRAIGHTENING MY HAIR is typically a two-day affair. I wash all the product out the night before and load my hair with hydrating protectants. I let it air-dry, then I braid it before bed so that the next day, the curls are looser and easier to work through. Then, and only then, can I go in with a flat iron.

WIRED's Gear members have an array of curl types, needs, and hair-styling tricks, and we've all tried a lot of hair straighteners in our lifetimes. Some flat irons have left us with crispy ends and cramped hands, while others, like the ones listed here, gave us sleek hair. There's a dizzying number of options around, but hopefully our favorite titanium hair straightener can help narrow down your search.

Updated December 2021: We've added more of our favorite tourmaline hair straightener, including the Bio Ionic 3-in-1 tool, the L'ange iron that blows cool air, and two honorable mentions. 

Special offer for Gear readers: Get a 1-year subscription to WIRED for $5 ($25 off). This includes unlimited access to WIRED.com and our print magazine (if you'd like). Subscriptions help fund the work we do every day.

Modern technologies have come up with ceramic hair straightener that are user-friendly. You no longer have to visit a salon if you want straight hair. However, using a hair straightener may not be easy for someone who has not used it before. Though flat irons are simple to use, one needs to be aware of the associated factors to ensure safety. If you are a beginner, here is a simple guide on how to use hair straightener at home.

Before you straighten hair at home, you need to prep your hair. Pollution, grease, various styling products, and dirt make your hair frizzy and unmanageable (1). Therefore, you need to wash your hair before straightening it.

Use a hydrating and nourishing shampoo to make your hair soft. Before you apply the flat iron on hair, make sure your hair is dry. Do not use a hair straightener on wet hair.

Choosing the right type of hair straightener is as important as preparing your hair for the straightening method. The market is flooded with plenty of straightening brands, and the abundance of options may end up confusing you. Here Checkout these Hair Straighteners as few options you can consider. Using a bad iron may end up damaging the hair severely.

Among many types of straighteners, flat irons are the best ones. They may be a little expensive compared to other types but are the best in terms of safety. When you are shopping for one, try to pick a straightener that comes with ceramic coating. This type of product is gentle for hair and provides hair with extra shine and health.

Personal image, as it relates to external beauty, has attracted much attention from the cosmetic industry, and capillary aesthetics is a leader in consumption in this area. There is a great diversity of products targeting both the treatment and beautification of hair. Among them, hair straighteners stand out with a high demand by costumers aiming at beauty, social acceptance and ease of daily hair maintenance. However, this kind of treatment affects the chemical structure of keratin and of the hair fibre, bringing up some safety concerns. Moreover, the development of hair is a dynamic and cyclic process, where the duration of growth cycles depends not only on where hair grows, but also on issues such as the individual's age, dietary habits and hormonal factors. Thus, although hair fibres are composed of dead epidermal cells, when they emerge from the scalp, there is a huge variation in natural wave and the response to hair cosmetics. Although it is possible to give the hair a cosmetically favourable appearance through the use of cosmetic products, for good results in any hair treatment, it is essential to understand the mechanisms of the process. Important information, such as the composition and structure of the hair fibres, and the composition of products and techniques available for hair straightening, must be taken into account so that the straightening process can be designed appropriately, avoiding undesirable side effects for hair fibre and for health. This review aims to address the morphology, chemical composition and molecular structure of hair fibres, as well as the products and techniques used for chemical hair relaxing, their potential risk to hair fibre and to health and the legal aspects of their use.

Attempts at beautification, mainly in women, especially involve the skin and its annexes 1. Personal image, as it relates to external beauty, has been the target of investment in the beauty industry, and in this context, the branch of capillary aesthetics has attracted much attention from the cosmetic industry because it is considered a leader in consumption in this area 2. As hair is one of the few physical features that can be easily modified to create a totally different style, be it in length, colour, or shape 3, there is a great diversity of products targeted for both the treatment and the beautification of hair; among them, hair relaxers and straighteners stand out. Generally, the term ‘relaxer’ refers to products intended for the treatment of kinky hair, while ‘straightener’ refers to products used for the treatment of curly hair – in this work, the term ‘straightener’ is used when referring to both products. The reasons for the use of hair dryer include beauty, social acceptance and ease of daily hair maintenance 1. However, these cosmetics affect only the hair shaft. As the newly developing hair will not be affected by these alterations, the new emerging hair will grow with its natural, original shape, and therefore, hair straightening needs to be repeated every 4–6 weeks 3. Thus, the emphasis in this cosmetic treatment should be only on new growth, as repeated treatments can lead to hair breakage 3, and scalp and hair disorders 4, among others 1, 4-6. Moreover, although the hair fibres are composed of dead epidermal cells, when they emerge from the scalp, there is huge variation in natural wave and the response to hair cosmetics 5. Consequently, for obtaining good results, it is essential to understand the mechanism of the process and other important information such as the composition of natural hair fibres, the composition of products and techniques available for hair straightening. Thus, this review aims to address a comprehensive summary of the morphology, chemical composition and molecular structure of hair fibres, as well as the products and techniques used for chemical hair straightening, their potential risk to hair fibre and to health and legal aspects of their use.

Hibiscus syriacus Extract from an Established Cell Culture Stimulates Skin Wound Healing
Higher plants are the source of a wide array of bioactive compounds that support skin integrity and health. Hibiscus syriacus, family Malvaceae, is a plant of Chinese origin known for its antipyretic, anthelmintic, and antifungal properties. The aim of this study was to assess the healing and hydration properties of H. syriacus ethanolic extract (HSEE). We established a cell culture from hibiscus extract and obtained an ethanol soluble extract from cultured cells. The properties of the extract were tested by gene expression and functional analyses on human fibroblast, keratinocytes, and skin explants. HSEE treatment increased the healing potential of fibroblasts and keratinocytes. Specifically, HSEE significantly stimulated fibronectin and collagen synthesis by 16 and 60%, respectively, while fibroblasts contractility was enhanced by 30%. These results were confirmed on skin explants, where HSEE accelerated the wound healing activity in terms of epithelium formation and fibronectin production. Moreover, HSEE increased the expression of genes involved in skin hydration and homeostasis. Specifically, aquaporin 3 and filaggrin genes were enhanced by 20 and 58%, respectively. Our data show that HSEE contains compounds capable of stimulating expression of biomarkers relevant to skin regeneration and hydration thereby counteracting molecular pathways leading to skin damage and aging.

Wound healing is a dynamic physiological process by which the skin regenerates itself upon injury. The restoration of tissue integrity is the result of the interaction between several distinct cellular elements (keratinocytes, fibroblasts, monocytes/macrophages, and endothelial cells) and extracellular matrix (ECM) components, such as fibronectin and collagen whose contraction encourages the edges of the wound to shrink together [1]. The supply of the ideal microenvironment at the wound surface is fundamental for reaching full skin wound's healing potential. Indeed, adverse factors, such as infection, mechanical stress, or toxic agents, can significantly affect the skin ability to heal. Additionally, the process of wound healing is altered in a dry skin and skin of aged individuals [2]. Skin dryness alters the ability of epithelial cells to migrate and cover the wound site and reduces the supply of white blood cells and nutrients, which are essentials to form new tissues and protect skin against infections [3].

Skin hydration depends on the humidity of the environment and the hygroscopic properties of the stratum corneum, the uppermost epidermal layer. The ability of the stratum corneum to retain water relies on the natural moisturizing factor (NMF), a set of substances including ions, small solutes, and free amino acids which are largely formed by the breakdown products of filaggrin protein [4].

Skin care products are often developed from plants. Higher plants are the source of a wide array of biochemicals that can support the health and integrity of the skin and are widely used in cosmetic formulations.

H. syriacus, family Malvaceae, is a plant of Chinese origin already known in Asia for its antipyretic, anthelmintic, and antifungal properties [5]. H. syriacus extract was previously shown to have antioxidant capacity [6] and antiproliferative effects on human lung cancer cells [7]. However, the leaves of hibiscus calyx extract genus are traditionally acclaimed as hair tonic in the Indian system of medicine. Accordingly, topical application of H. syriacus extract was found to stimulate hair growth thereby validating the ethnomedical use of this plants for hair loss treatment [8].

Remarkably, H. rosa-sinensis of the genus hibiscus extract powder was previously reported to efficiently act as wound healing agent by increasing cellular proliferation and collagen synthesis [9]. More recent in vitro and in vivo studies indicated Hibiscus syriacus L. flower absolute (HSF) as a highly effective agent for wound treatment because of its ability to promote keratinocyte proliferation and migration [10].

A chemical study performed on raw material from the epigeal part of the plant revealed the presence of flavonoids [dihydroquercetin, herbacetin, kaempferol, saponaretin, and saponarin] previously demonstrated to be able to reduce UVB-induced erythema and tumorigenesis [11]. Furthermore, H. syriacus extract was also found to be rich in anthocyanins, fatty acids, and several types of pigments [12].

Nowadays, cell suspension cultures from plants provide a viable alternative over whole plant cultivation for the production of secondary metabolites. They represent standardized, contaminant-free, and biosustainable sources of beneficial bioactive compounds for cosmetics on an industrial scale [12, 13].

We have established stem cell suspension cultures of H. syriacus and prepared a hydro/alcoholic extract rich in flavonoids and coumarins. Here, we present a study aimed at evaluating the wound healing and hydration properties of Hibiscus syriacus extract from cell suspension culture.

Since ancient times, Hibiscus. species (Malvaceae) have been used as a folk remedy for the treatment of skin diseases, as an antifertility agent, antiseptic, and carminative. Some compounds isolated from the species, such as flavonoids, phenolic acids, and polysaccharides, are considered responsible for these activities. This review aims to summarize the worldwide reported biological activities and phytoconstituents associated with this genus for the past 40 years.

Hibiscus. (Malvaceae) is a genus of herbs, shrubs, and trees; its 250 species are widely distributed in tropical and subtropical regions of the world. About 40 species occur in India. Many Hibiscus. species are valued as ornamental plants and are cultivated in gardens. Some species, such as Hibiscus cannabinus. L. and Hibiscus sabdariffa. L., are important sources of commercial fiber, whereas some species are useful as food, and yet others are medicinal (Anonymous, 1959). Many species belonging to this genus have been used since ancient times as folk remedies for various disorders. In Ayurveda, Hibiscus esculentus. L. fruits are considered tonic, astringent, and aphrodisiac. In Unani medicine, the fruits are considered emollient and useful for treating urinary disorders (Parrotta, 2001). The leaves and roots of Hibiscus manihot. L. are used as a poultice for boils, sprains, and sores, and the flowers are used to treat chronic bronchitis and toothache. The mucilage of the bark is considered to be an emmenagogue (Chopra et al., 1950). The seeds of Hibiscus abelmoschus. L. are valued for their diuretic, demulcent, and stomachic properties and are considered stimulant, antiseptic, cooling, tonic, carminative, and aphrodisiac. The bark, flowers, and fruits of Hibiscus bauiferus. J.G. Froster are used externally for the treatment of skin diseases such as eczema, scabies, psoriasis, and ringworm. In Ayurvedic medicine, the bark is the official source of the drug “parisha,” a reputed remedy for skin diseases (Parrota, 2001).

According to the literature, many Hibiscus. species have been investigated and found to contain many classes of secondary metabolites, including flavonoids, anthocyanins, terpenoids, steroids, polysaccharides, alkaloids, amino acids, lipids, sesquiterpene, quinones, and naphthalene groups. Some of these compounds have been shown to have antibacterial, anti-inflammatory, antihypertensive, antifertility, hypoglycemic, antifungal, and antioxidative activities (Kholkute et al., 1977a; Parmar & Ghosh, 1978; Gangrade et al., 1979; Jain et al., 1997; Faraji & Tarkhani, 1999; Lin et al., 2003; Sachdewa & Khemani, 2003).

This review describes the currently available chemical and biological data on the genus Hibiscus. and suggests that the flavonoids and phenolic acids are the main classes of substances of interest to a phytochemist and pharmacologist. A number of reports have been published to establish the biological potential of this genus (Table 1).

Canthin-6-one (2) and a fatty acid fraction that contained lauric, myristic, and palmitic acids isolated from stem bark of hibiscus flower extract powder showed antifungal activity against Trichophyton interdigitale. (Yokata et al., 1978). The seed oil of Hibiscus syriacus. has shown antimicrobial activity against Gram-negative and Gram-positive microorganisms. The oil was resistant against Salmonella typhi. but showed activity against Escherichia coli, Salmonella newport, Staphylococcus aureus, Staphylocoecus albus, Bacillus subtilis., and Bacillus anthracis.. The oil has shown significant fungicidal activity against tested plant pathogens, viz., Alternaria solani, Aspergillus niger, Colletotri-chum dematium., and Fusarium oxysporum. (Shah et al., 1988). The oil and the unsaponifiable matter from Hibiscus sabdariffa. were found to exert antibacterial activity against Escherichia coli, Staphylococcus typhimurium, Bacillus anthracis, Bacillus subtilis, Staphylococus aureus, Staphylococcus albus. and Klebsiella pneumoniae.. These compounds also exhibited antifungal activity against Aspergillus flavus, Trichophyton equingea, Helminthosporum rostatum, Crypto-coccus neoformans, Tricnoderm viridi, Colletotrichum falca-tum., and Alternaria solanacea.(Gangrade et al., 1979). The aqueous extract of the calyx of Hibiscus sabdariffa. and protocatechuic acid derived from roselle calyx inhibited effectively the growth of bacterial pathigens, viz., methicillin-resistant Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa., and Acinetobacter baumannii.. The antibacterial activity of protocatechuic acid was greater than the extract (Lin et al., 2005). The ethanol extract of aerial parts and roots of Hibiscus micranthus. L. showed antibacterial activity against Staphylococcus aureus. and antifungal activity against Fusarium moniliforme, Aspergillus flavus, Aspergillus niger., and Rihzoctonia bataticola.(Jain et al., 1997).

The trinorcandalene phytoalexins, hibiscanal (3) and o.-hibiscanone (4) isolated from stem stele of hibiscus sabdariffa extract. inoculated with fungal pathogen Verticillium dahliae. killed all propagules of Verticillium dahliae. in the concentration range of 1–18 μg/mL (Bell et al., 1998). The volatile oil from the leaves of Hibiscus cannabinus., composed of 58 components of which the major components were (E.)-phytol, (Z)-phytol, n.-nonanol, benzene acetaldehyde, (E.)-2-hexenal, and 5-methylfur-fural, showed antifungal activity against Colletotrichum fragariae, Colletotrichum gloeosporioides., and Colletrotri-chum accutatum. at 400 and 100 μg. Among the major components of the oil, only 5-methyl furfural, n.-nonanol, and benzene actaldehyde have shown antifungal activity (Kobaisy et al., 2001).

The use of Hibiscus. species as an antifertility agent has been a long-time rural folk practice in India (Chopra et al., 1950; Anonymous, 1959). Bhavamishra also mentioned this during the 18th century in Yonirogadhikar, in the 70th chapter of Bhavaprakash.. He stated that a woman could never get pregnant if she consumes during her menses a preparation made from the flowers of Hibiscus rosa-sinensis. L. and fermented rice broth, along with the old jaggery. An extensive study to screen the antifertility effect of Hibiscus rosa-sinenesis. has been done. The benzene extract of the flower of Hibiscus rosa-sinensis. at the dose of 73 mg/kg body weight, disturbed the estrous cycle in rats and reduced ovarian, uterine, and pituitary weight (Kholkute et al., 1976). The maximum antifertility activity of the total benzene extract of Hibiscus rosa-sinensis. was mediated via inhibition of implantation (Kholkute & Udupa, 1976a). The total ethanol extract of the flowers of Hibiscus rosa-sinensis. also showed similar activity but was less potent than the benzene extract (Kholkute & Udupa, 1976b). The antifertility activity of flowers of Hibiscus rosa-sinensis. was affected by seasonal variations. The benzene extract of the flowers collected in winter showed maximum potency, followed by those collected in the spring, rainy season, and summer, in decreasing order (Kholkute et al., 1977). The ether-soluble portion of the water-insoluble fraction of the benzene extract of Hibiscus rosa-sinensis. flowers have shown significant anti-implantation and abortifacient effects in female albino rats (Singh et al., 1982). The benzene extract of Hibiscus rosa-sinensis. flowers, when administered intraperitoneally at dose levels of 125-250 mg/kg body weight to adult mice, resulted in an irregular estrus cycle with prolonged estrus and metestrus. An increase in the atretic follicles and absence of corpora lutea indicated the antiovulatory effect of the extract. Estrogenic activity of the benzene extract in immature mice was also evident by early opening of the vagina, premature cornification of the vaginal epithelium, and an increase in uterine weight (Murthy et al., 1997). The aqueous extract of the leaves of Hibiscus rosa-sinensis. at a dose of 100 mg/kg body weight has shown anti-implantation activity. The extract showed a sharp increase in superoxide anion radical and a sharp fall in superoxide dismutase activity. It also showed antiestrogenic activity (Nivsarkar et al., 2005).

An aqueous extract from the leaves of Hibiscus macar-anthus. Hochst ex A.Rich, when given daily to 22-day-old female rats for 5, 10, 15, 20, and 25 days, have shown a decrease in the growth rate of animals. The ovarian and uterine weights were high during the pubertal period (36–41 days). During the same period, the ovarian and uterine protein, ovarian cholesterol, and serum cholesterol levels showed significant differences in treated rats when compared with controls. The ovarian and uterine protein levels as well as the serum cholesterol level were high in animals treated with 49 mg/kg per day of plant extract. A decrease in ovarian cholesterol level was observed in the same group thereby suggesting the presence of an estrogenic compound in plant extract (Telefo et al., 1998).

Are Casement Windows a Practical Choice for Your Home?
It’s just as important to choose the right windows for your home as it is to select suitable doors. Apart from how the window looks, it should also meet functional specifications, including how much ventilation and light you require, how it opens and if it comes with safety features. Generally, the most common types of windows are double-hung, sliding, and casement windows.

Casement windows are rising in popularity in Malaysian homes, and it’s easy to see why. They are stylish and works well in many modern abodes. For those who are not familiar with casement windows, let’s look at what casement windows are and how they work.

As its name suggests, a casement window features a window frame hinged to a sash which allows it to swing open inward or outward from the side. Thus, they come into two types of opening: inward opening and outward opening.

This type of window is typically a simple structure, flexible and offers good sealing performance, making it a favourable choice for those who want a more minimalist appearance for their home’s architectural style. If you are wondering whether it is a practical choice for your home, read on to learn more about the benefits of a casement window.

If you want a window that maximises natural light and let in more airflow, casement windows do a great job. Due to their minimalist design, they also offer a broader, clearer view of your outdoors, evoking a seamless indoor-outdoor environment.

Window Elements’ Optima 38 is designed with a dramatically wide and deep frame, which instantly creates a statement-making feature in your home. Ideal for bungalows and mansions as well as houses with classic or tropical themes, its elegant frame enhances the aesthetic appeal of your interior while ensuring your living spaces receive optimal views, air, and daylight. A selection of glass is also available, and you can opt for a lattice design or full glass.

More than just a good-looking element, a casement window contributes to the safety of your home as well. Thanks to advanced features and high-strength materials, today’s casement windows have earned a placed in a home’s security system. When designed in combination with innovative functions, casement windows are effective in securing the home from burglary attempts.

Designed with your ultimate home safety in mind, Window Elements’ exquisite aluminium casement windows are highly secure yet elegant at the same time. Take Window Elements’ ArxTech casement window system for example. One of the most flexible systems available in the market, ArxTech casement window is made from premium quality aluminium and comes with high tensile stainless steel security mesh. Featuring a clean-line design with square-edged inner frames adjacent to the outer frame, along with concealed hinges, this casement window provides expansive views from the inside when the window is opened. When closed, you can rest assured your house is well-protected.

Without doubt, casement windows are beautiful with their sleek edges, and streamlined design. From the outside, it gives your home’s facade a modern urban look, while from the inside, it blends in with any interior style with its minimalist appearance.

Made from premium aluminium that is lightweight and clean-cut, Window Elements’ Optima 29 casement window is perfect for complementing a modern minimalist home. Featuring a sleek design with square-edged inner frames adjacent to the outer frame, the window also incorporates concealed hinges and a water drainage channel. The mullion (the vertical bar between the windowpanes) is attached to the window panel, giving you the perfect view from inside out when opened. All these design elements contribute to a “less is more” outlook. In addition to Optima 29’s good looks, this casement window also offers good ventilation, high sealing performance, excellent sound insulation, heat preservation and impermeability.

Whether you seek a window that blends aesthetically with your home exterior and interior, or one that ensures your home is safe and sound, Window Elements’ premium range of aluminium casement windows is an excellent investment for your property. To answer the question in the title, casement windows are indeed a practical choice; in fact, they go beyond offering functional benefits, as they are incredibly stylish and secure at the same time.

uPVC casement doors can be opened both inwards and outward with the support of the hinges fastened on a frame. The casement doors are put in with sashes with many modern modifications that enable the casement hardware to work simply and provides long run performances. The casement doors made up of sturdy, high-quality uPVC material comes with a multi-locking feature to make sure total safety. Also, the casement doors are the most effective choice to direct the breeze within your home. These casement doors are available in enticing colours to suit the client needs. They’re suitable for places like Living rooms, Washrooms and Kitchens! The casement doors together with their sturdiness additionally offer 100 per cent opening, dustproof and soundproof properties. This article elaborates on Why uPVC Casement Doors are Popular.

Aluminum casement doors are doors that will be opened inwards /outwards with the assistance of hinges fastened on a frame. uPVC casement doors come back up with an updated modern twist and are designed with the highest quality casement hardware to create them pretty much simple to work and last for much longer and it will even be organized for opening within and out of doors. Also, the casement doors are perfect to enjoy the beautiful scenery of the outdoors.

The casement doors are made of sturdy materials that have wonderful thermal and acoustic properties of insulation. The simple and elegant style of these casement doors once it’s combined with the multi-locking points and ensures that they’ll offer total security. This type of door is best for providing ventilation for the house. Position these in such a simplest way that they’ll be ready to catch the breeze and direct it within your home. Offer your home an exquisite, enticing gift through the casement Door. Besides, a uPVC casement door will increase the worth of your home.

Casement Doors
UPVC casement door comes with a hundred and eighty degrees opening that brings additional ventilation to your home. Casement doors are the proper alternative for a Soundproof and energy protection system. casement doors reach up to 45dbs with DGU. The casement door suits the bedroom, lobby area, bathroom, room entrance etc. The thermal break casement door comes with 0.5 space glass and 0.5 space uPVC sheet or full space as glass. Moreover, the casement door has a high secured cylinder protection mechanism with a double access key. The casement door has an air adjustment mechanism to prevent energy leaks. The casement door comes in varied colours to grant attraction to your home. Besides, the casement door has five-chamber extrusion technology that helps to cut back the warmth and sound. UPVC casement door surprises you with the smooth operative, metallic handles and hardware.

The casement door comes with four 3D hinges wherever every hinge will bear 120 kilograms of weight so hinges will hold the shutter with high strength. Casement door comes with totally different styles like commercial casement door cum fixed window and sliding with casement etc. All the casement doors consist of imported hardware and the Espag mechanism.

Casement windows have an unusual construction, especially when they’re propped open. Unlike a lot of window styles that slide open to one side, or up and down, casement windows are hinged on a side and crank outward.

The outward prop style makes for an interesting design that some homeowners seem to love while others share not quite as much excitement for. The style is very popular in kitchens, especially over sinks, because of the outstanding ventilation, yet can be used in a number of different rooms.

Characteristics
Casement windows are very open in how they open and close. Instead of a sliding mechanism, the window is attached to a crank that drives the opening and shutting feature. The exterior hinges of the window enable complete, top to bottom ventilation.

The design is popular for kitchens where cooks like to get more ventilation than other sections of the house. The full ventilation can help remove strong odors or other smells from the kitchen, as well as help provide a nice breeze in certain times of the year.

Awning Windows
Casement style windows that are hinged at the top are known in the industry as awning windows. If you prefer this type of hinge it is important to regard them as awning casement windows so the service member can understand exactly what you want installed.

Hoppers
Windows that are casement style and hinged at the bottom are considered hoppers. A good way to picture them is like the name implies, something that is hopping inwardly to the interior of the home.

FCL Windows
A type of casement window that opens from the left-handed side of the frame. The hinges are also on the left, while the locking mechanism is on the right when looking at it from the exterior.

FCR Windows
A type of window that opens from the right-handed side of the frame. Everything is the exact opposite of an FCL opening window, so the locking mechanism is on the left and hinges on the right.

A lever, crank, or cam handle is used to open and shut these types of windows. The crank or cam handle can help support the outwardly positioned window pane when a breeze or gust picks up outside. The one major knock is you have to be careful with these when they’re positioned open, as strong winds can be hard on the hinges and even rip them off.

When the glass panes are installed they are usually set in a rabbeted frame then sealed with some type of beveled putty or glazing. The compound helps secure the glass as well as help with energy efficiency.

Casement windows are often combined in two or more window frames though some only prefer a singular window. The combination of frames may include window panes that open and ones that do not. When combined together they can provide a nearly full wall view of an exterior, as well as a friendly indoor breeze.

History
Casement windows have a long history. In Europe, the style was used before the sash window was introduced. The early designs were built with a metal frame and had leaded glass.

The initial designs were still hinged, yet opened inward to the interior of the building. During the Victorian era, the designs were improved as they began to open outward and also featured shutters. It wasn’t uncommon for builders to construct the casement from timber in its entirety.

Casement style windows continue to remain popular in Europe and are also built in America though not quite as common.

A gun drill mechanics model analysis
Gun drilling is a process used to produce small-diameter holes at a high depth-to-diameter ratio, beyond what is capable using conventional tooling, especially for difficult-to-machine superalloys such as titanium, Inconel, Monel, etc. Presently, it often incapacitates by low productivity, rapid tool wear, frequent tool breakages, and straightness deviation. This chapter addresses the challenges of tackling these problems by employing game-changing approaches and technologies. Existing research in the advanced gun drilling technologies tends to focus on the choice of drilling parameters. There is little literature available for the cutting mechanics and workpiece deformation, tool geometry, wear and failure mechanism, especially in the deep hole drilling process for superalloys. Consequently, the aim of this chapter is to provide an overview of how the game-changing approaches and technologies for advanced gun drill tool can be explored and utilized.

The drilling of deep holes by means of deep hole gun drill is investigated so as to establish the parameters of the guide hole and its production. The rate of change in the load on the tool is proportional to the active length of the primary cutting edge. Assessment of the smoothness of tool insertion on the basis of the rate of change in the load on the tool is proposed.

Referencing special energy model, a new gun drill mechanics model was established and the influence of the cutting parameters on axial force and torque was based on 15-5PH solid solution stainless steel through theoretical analysis and cutting tests. On the basis of the existing model, the model coefficients were modified under various cutting conditions and the integral area of the cutting edge was enlarged. The eccentricity at the bottom of the drill groove was taken into account in the integral area of the cutting edge. In the meanwhile, the torque calculation was simplified reasonably according to the theoretical analysis. The feasibility of the model was verified by experiments and the influence of cutting parameters on the axial force and torque was analyzed. The experiment data had shown that the relative error between the calculated values and the experimental values were within the acceptable range. The axial force and torque increased with the increase in cutting speed and feed rate.

Drilling mechanics model has always been the key and difficult point in the research field of solid carbide gun drill. In this paper, through theoretical analysis and processing experiments, the gun drilling mechanics model of Ti6Al4V titanium alloy is studied. On the one hand, based on the Oxley cutting model and the Johnson-Cook flow stress model, this paper takes Ti6Al4V titanium alloy as the research object and use the “microelement” method to establish the mechanical model of gun drilling, which includes cutting parameters, tool geometric parameters and material mechanical properties. On the other hand, the drilling model considers the influence of process damping and verified by experiments. The results show the calculated value of the model is consistent with the experimental value and the error is within the acceptable range. The model provides a theoretical basis for the prediction of drilling force, tool analysis and straightness error analysis.

The dynamics of the gun drilling process is analyzed in this paper. The tool shank is modeled as long straight beam vibrating in transverse direction under action of cutting forces. Axial force component is expressed as proportional to cutting thickness, which is determined as nonlinear function of beam transverse deflection with time delay. Nonlinear equations of motion of the drilling shank are derived. The stability diagram of the system dynamics was determined. The bifurcation analysis of nonlinear differential delay equations by means of multiple scale method was performed. The obtained results were verified by numerical integration of nonlinear equations. The influence of cutting conditions on system stability and chatter amplitude was observed.

Long straight holes are usually produced by means of a special drilling tool. This efficient process is widely used in the automotive industry to drill deep holes in cylinder heads, crankshafts, fuel pump housings, turbine blades and etc. Gundrilling is the mostly used method of deep small hole machining. Gun drill has asymmetrical single edge tool design with long straight tube of asymmetrical cross-section with a typical reachable diameter range of 0.5 mm up to 40 mm and length-to-diameter- ratios up to / = 400 (in special applications even / = 900 [1]). The method is widely applied in machining small deep holes as it provides a good straightness and high quality of machined surface due to its self-guiding action [2]. Optimal drill performance in gundrilling is achieved when the combination of the cutting speed, feed rate, tool geometry, carbide grade, and coolant parameters are selected properly depending upon the work material, deep-hole tool machine conditions, and the quality requirements to the drilled holes. Due to low flexural stiffness of gun drill shank lateral vibrations of high magnitude could be excited during the machining. Excessive vibrations are detrimental to finish surface quality and may damage the tool. Therefore, it is important to predict in advance regimes with chatter vibrations. The regenerative mechanism is the main source of chatter vibrations. And it requires that time-delayed terms in model equations should be taken into account. The same mechanism emerges not only in drilling [3-5], but in milling [6], boring etc. The comprehensive review of present state of deep hole drilling modeling was given in [1]. Most authors modeled drill shank using the reduced single degree of freedom system. In this insert gun drill is considered as flexible continuous beam loaded with eccentrically applied cutting force. The new approach allows considering the influence of lateral vibrations on the dynamics of the gun drilling system. The multiple scale method is applied for nonlinear vibrations analysis. Stability diagram was constructed and bifurcation diagrams were obtained by multi-scale expansion. The nonlinear behavior of system in vicinity of stability borders was analyzed by using numerical integration of nonlinear equation.

Gun drill shank is modeled as long slender beam using Euler-Bernoulli beam theory. The beam axial line is supposed to be straight line in undeformed state. Schematic of gun drilling process is presented on Fig. 1. Usually gun drill rests upon intermediate supports, but we suppose that clearance in these supports is large enough, so that these supports are not taken into consideration. Therefore, for the sake of simplicity we assume, that gun drilling shank as simply supported beam.

In this paper nonlinear model of chatter vibrations of gundrilling tool is presented. Stability diagram of the linearized system was obtained. The relative cutting speed is the main critical parameter which effects on process stability. Post-critical behavior after stability loss was analyzed by means of method of multiple scales. The bifurcation diagrams of the dimensionless cutting speed (speed of detail rotation) influence on chatter vibration amplitude were determined. The results of numerical simulation and the nonlinear equation asymptotic solution showed good agreement. Presented model could be used for stability analysis and for prediction of amplitudes of chatter in unstable zone. The results of modeling can be exploited in industry for optimal cutting conditions determination.
The IMSA MF1000C is equipped with an ISO40 spindle (13 kW, 6000 rpm) used both for drilling and for the milling. Gun drills are used for deep drilling and are guided along the entire length by steady rests.

One strong point is the "Swing on Top System" developed by IMSA, which enables a smooth transition from deep drilling to milling and vice versa in a short time. The entire drilling unit, including the chip box and the steady rests, swings upwards leaving the spindle free in order to perform the milling. The manual disassembly of components of the machine by the operator is not necessary. In the milling configuration, the spindle is positioned on the front part of the machining unit, toward the workpiece. From the five places in the tool store, the appropriate tool is loaded onto the spindle (cutter, twist drill, thread cutter,…) and processing can start immediately.

The MF1250/2FL does not require continuous attendance by an operator during operation, and it is capable of drilling many meters before the diamond gun drill needs to be re-sharpened. This gun drilling and milling machine is designed and manufactured to make moulds weighing up to 6 ton, with a diagonal of up to 1900 mm (diameter in rotation within the structure of the machine). This model is equipped with a rotary/tilting table as a standard. This makes it possible to drill complex cooling circuits with compound angle drilling, thanks to the combination of table rotation 360,000 pos/rev and the ±22,5° tilting movement in infinite position.

The dual-spindle headstock configuration allows fully automatic switchover in a few seconds, with no intervention required by the operator. The MF1250/2FL indeed has two spindles: a gun drilling head and an ISO40 machining spindle, positioned on the same headstock above the gun drilling head. Both spindles are liquid-cooled.

The machine is equipped with an ISO tool changer magazine for 12 tools as a standard; however, magazines holding 24 to 40 tools are also available in option.

As regards axis positioning, the MF1250/2FL uses optical scales. The machine is increasingly used to perform pocket milling and precision guides, or for ejector drilling. The precision offered by a positioning system with optical scales for these tasks is significant.

Our EVO Series, that currently consists in 3 models, is the evolution of our top performing BB Series.

The MF1350EVO gun drilling and milling machine is designed and manufactured to drill moulds up to 12 tonnes, with a diagonal of up to 2.600 mm as diameter in rotation within the machine structure.

The structure rigidity that comes from the vertical gantry column gives as a result the same high performance in drilling large diameters regardless of the vertical position.

Compound-angle deep holes are executed by combining the table rotation and the headstock tilting movement (from -20° to +20°). Long transversal movements increase the approach to workpiece, so that the workpiece is only set up once on the table centre.

The headstock accommodates the two spindles: gun drilling spindle and auxiliary spindle, now both liquid-cooled.

IMSA technical team performed a complete revision of the projects from our previous BB Series, with the new EVO Series as a result. The increased stresses during machining, caused by the higher-performance new spindles, are distributed on a machine structure that has been reengineered.

This high-tech concept includes, in particular, transmissions by planetary gear boxes, optical measuring systems, liquid-cooled spindle motors, oil management by inverter and cnc.

Preliminary Design on Screw Press Model of Palm Oil Extraction Machine
The concept of the screw press is to compress the fruit bunch between the main screw and travelling cones to extract the palm oil. Visual inspection, model development and simulation of screw press by using Solidworks 2016 and calculation of design properties were performed to support the investigation. The project aims to analyse different design of screw press which improves in reducing maintenance cost and increasing lifespan. The currently existing of screw press can endure between 500 to 900 hours and requires frequent maintenance. Different configurations have been tried in determination of best design properties in screw press. The results specify that screw press with tapered inner shaft has more total lifespan (hours) compared existing screw press. The selection of the screw press with tapered inner shaft can reduce maintenance cost and increase lifespan of the screw press.

The palm farmers of Bangladesh are suffering for want of an extraction machine. Therefore, a research was undertaken to design and develop a manually operated palm oil extraction machine at the department of Farm Power and Machinery, Bangladesh Agricultural University. It is a press type machine. A screw leads a piston manually in a perforated cylinder to press the mesocarp (pulp of palm fruit) to extract oil. The volume of the cylinder of the machine was found 0.03 m3 and maximum 20 kg fruits can be accommodated at a time. The amount of crude palm oil press at full capacity of the machine was found 8 kg/hr., which is higher than any manually operated extracting machine available in the market. The crude oil extraction efficiency of the machine without palm kernel was also found satisfactory. Application force on screw can be increased by increasing the length of the handle and number of persons according to filling condition of the cylinder. The machine was developed with locally available materials for having low purchase price and smooth repair and maintenance. So that, it will be easily affordable to the palm farmers of Bangladesh. The developed machine will solve the burning need of palm farmers in Bangladesh.

One of important sources of biomass-based fuel is Jatropha curcas L. Great attention is paid to the biofuel produced from the oil refinery extracted from the Jatropha curcas L. seeds. A mechanised extraction is the most efficient and feasible method for oil extraction for small-scale farmers but there is a need to extract oil in more efficient manner which would increase the labour productivity, decrease production costs, and increase benefits of small-scale farmers. On the other hand innovators should be aware that further machines development is possible only when applying the systematic approach and design methodology in all stages of engineering design. Systematic approach in this case means that designers and development engineers rigorously apply scientific knowledge, integrate different constraints and user priorities, carefully plan product and activities, and systematically solve technical problems. This paper therefore deals with the complex approach to design specification determining that can bring new innovative concepts to design of mechanical machines for oil extraction. The presented case study as the main part of the paper is focused on new concept of screw of machine mechanically extracting oil from Jatropha curcas L. seeds.

The use of bioenergy as energy derived from biofuels in the world permanently increases [1, 2]. Biomass-based fuels as renewable organic source of bioenergy have advantages (e.g., no harmful carbon dioxide emissions, reduction of dependency on fossil fuels, and versatility) and some disadvantages (e.g., requiring more land, relative ineffectiveness when compared to gasoline, and problematic supply chain) as well [3–6]. One of important sources of biomass-based fuel is Jatropha curcas L. [7–10]. Jatropha curcas L. is crop with inconsiderable potential due to its high oil content, rapid growth, easy propagation, drought tolerant nature, ability to grow and reclaim various types of land, need for less irrigation and less agricultural inputs, pest resistance, short gestation periods, and suitable traits for easy harvesting enumerated [11]. Biooil extracted from Jatropha curcas L. seeds has positive chemical properties (e.g., better oxidative stability compared to soybean oil, lower viscosity than castor oil, and lower pour point than palm oil) [12]. Jatropha significant advantage is that it is one of the cheapest sources for biodiesel production (compared to palm oil, soybean, or rapeseed) [13]. On the other hand former and recent findings [14–17] also show that researchers, economists, biochemists, farmers, machine designers, and biofuel producers should not just automatically follow the initial Jatropha hype but critically reflect on, for example, current economic situation, state biofuel policy, institutional factors, labour costs, water irrigation, local differences, and last but not least farmer’s needs. The evaluations [15], for example, opened many questions connecting with Jatropha processing profitability. One of the recommendations in [15] mentioned mechanised extraction as the most efficient and feasible method for oil extraction for small-scale farmers. Consequently one of the strategies of how to produce biofuel from Jatropha curcas L. in more efficient manner is to increase the effectiveness of oil processing machine, which would increase the benefits of small-scale farmers. This objective can be achieved through the further innovations of mechanical expellers or presses for small-scale farmers. Due to the great attention paid to this issue [18–26] innovators should be aware that further Jatropha-presses development is possible only when applying the systematic approach and design methodology in all stages of engineering design as an essential part of Jatropha-press life-cycle. Systematic approach in this case means that designers and development engineers rigorously apply scientific knowledge, integrate different constraints and user priorities, carefully plan product and activities, and systematically solve technical problems. Basic phases of the engineering design process have been in the past developed into more detailed procedures focused on the systematic development [27–33], on creative solution of technical problems [34–37], or on the preliminary and detailed embodiment design [38–40]. The correct definition of the right problem in the form of design specifications is widely regarded as a decisive step towards the effective implementation of all engineering design procedures [41–43]. Two information transformations are required to determine design specification. During the first information transformation the user’s needs are translated to functional requirements. The second information transformation takes place when converting the functional requirements to machine characteristics (design specifications) that have been selected to ensure fulfilment of specified functional requirements. By performing these transformations design assignment is then defined as an information input to concept generation phase and subsequent detailed designing. During this process various methods such as marketing research [44, 45], voice of customer (VOC) [46, 47], usability testing (thinking aloud protocol) [48, 49], Kansei engineering [50, 51], or quality function deployment (QFD) [52–54] are systematically utilized. Innovation science using function-object analysis [55, 56] or main parameter value [57] is also important to mention. For the conceptual design phase of innovation process is suitable to use modern creative techniques supporting idea generation and overcoming technical and physical contradictions based on TRIZ [58–61]. The process of concept generation is finished by choosing between concept alternatives by simple evaluation charts [28] or advanced techniques or analytic hierarchy process [4]. Since the above methods are becoming standards when upgrading technical products in 21st century it is clear that further development and innovation of machine for mechanical extraction of oil from Jatropha curcas L. require similar advanced techniques and methods.

In today’s world of technology, which leads to accelerated development, for example, in technologies or material science, to include to the mentioned transformations only information from users (farmers) or information about other similar products is insufficient. That is because users do not have and cannot have sufficient knowledge of the possibilities of current technologies or have not access to information about trends in the relevant fields of technology. Users (farmers) can only guess at what is possible in present and near future design. For that reason it is necessary to enrich traditional approach to determination of the design specification. First technological, ecological, economic, and social trends should be included in a set of functional requirements (needs)—Figure 1. Second relevant engineering characteristics with affinity to technological, social, or economic trends should be involved into process of design specification determining as well (Figure 1). Third designers should additionally include information obtained by modelling that can objectively on the basis of physical and chemical laws extend set of suitable engineering characteristics describing future machine (Figure 1).

Basic functions of the oil dewaxing machine consist in separating the solid component (structures) and liquid component (oil). Linear or nonlinear pressing (vertical, horizontal, or angled) by a sliding piston or rotary screw is frequently used for small-scale production. As the technological set-up for Jatropha processing is not yet fully developed and progress may be made in terms of mechanisation [15] we present mentioned complex approach in the following case study focused on conceptual design of screw extractor press extracting biooil from Jatropha curcas L. seeds for small-scale production. First, the research team analysed sources [7–9, 13–17, 19] and information obtained during interview realized in Sumatra and Java (Indonesia)—Figure 2. Low production cost [14], high productivity [16], and higher oil yield [19] were considered as essential extracting machines user’s needs (Table 1).

How Does a Generator Create Electricity? 
Kohler.jpgGenerators are useful appliances that supply electrical power during a power outage and prevent discontinuity of daily activities or disruption of business operations. Generators are available in different electrical and physical configurations for use in different applications. In the following sections, we will look at how a multi-function immunity generator functions, the main components of a generator, and how a generator operates as a secondary source of electrical power in residential and industrial applications.

An electric generator is a device that converts mechanical energy obtained from an external source into electrical energy as the output.

It is important to understand that a generator does not actually ‘create’ electrical energy. Instead, it uses the mechanical energy supplied to it to force the movement of electric charges present in the wire of its windings through an external electric circuit. This flow of electric charges constitutes the output electric current supplied by the voltage dip generator. This mechanism can be understood by considering the generator to be analogous to a water pump, which causes the flow of water but does not actually ‘create’ the water flowing through it.

The modern-day generator works on the principle of electromagnetic induction discovered by Michael Faraday in 1831-32. Faraday discovered that the above flow of electric charges could be induced by moving an electrical conductor, such as a wire that contains electric charges, in a magnetic field. This movement creates a voltage difference between the two ends of the wire or electrical conductor, which in turn causes the electric charges to flow, thus generating electric current.

Extensive efforts have been made to harvest energy from water in the form of raindrops1,2,3,4,5,6, river and ocean waves7,8, tides9 and others10,11,12,13,14,15,16,17. However, achieving a high density of electrical power generation is challenging. Traditional hydraulic power generation mainly uses electromagnetic generators that are heavy, bulky, and become inefficient with low water supply. An alternative, the water-droplet/solid-based triboelectric nanogenerator, has so far generated peak power densities of less than one watt per square metre, owing to the limitations imposed by interfacial effects—as seen in characterizations of the charge generation and transfer that occur at solid–liquid1,2,3,4 or liquid–liquid5,18 interfaces. Here we develop a device to harvest energy from impinging water droplets by using an architecture that comprises a polytetrafluoroethylene film on an indium tin oxide substrate plus an aluminium electrode. We show that spreading of an impinged water droplet on the device bridges the originally disconnected components into a closed-loop electrical system, transforming the conventional interfacial effect into a bulk effect, and so enhancing the instantaneous power density by several orders of magnitude over equivalent devices that are limited by interfacial effects.

Extensive efforts have been made to harvest energy from water in the form of raindrops1,2,3,4,5,6, river and ocean waves7,8, tides9 and others10,11,12,13,14,15,16,17. However, achieving a high density of electrical power generation is challenging. Traditional hydraulic power generation mainly uses electromagnetic ESD Generator that are heavy, bulky, and become inefficient with low water supply. An alternative, the water-droplet/solid-based triboelectric nanogenerator, has so far generated peak power densities of less than one watt per square metre, owing to the limitations imposed by interfacial effects—as seen in characterizations of the charge generation and transfer that occur at solid–liquid1,2,3,4 or liquid–liquid5,18 interfaces. Here we develop a device to harvest energy from impinging water droplets by using an architecture that comprises a polytetrafluoroethylene film on an indium tin oxide substrate plus an aluminium electrode. We show that spreading of an impinged water droplet on the device bridges the originally disconnected components into a closed-loop electrical system, transforming the conventional interfacial effect into a bulk effect, and so enhancing the instantaneous power density by several orders of magnitude over equivalent devices that are limited by interfacial effects.

The uses of natural gas, fuel, and coal to generate electricity have become detrimental for human-beings because of their adverse effects on atmospheric pollution and global warming. Nevertheless, according to the US Energy Information Administration (EIA), electricity generated from power plants using natural gas was increasing every year with 28% in 2014, 35% in 2018 and 36% in 2019 (U.E.I. Administration, 2018). Furthermore, the world consumption and production of liquid fuels increased from 94 million barrels per day in mid-2014 to 100 million in mid-2018, which is leading to an ever-increasing energy cost. To cope with this global growth in the consumption of fossil fuels, quite expensive and polluting, other forms of environment-friendly energies arose in the last decades. Indeed, Nicolas Tesla once said: “Electric power is everywhere present in unlimited quantities and can drive the world’s machinery without the need of coal, oil, gas or any other of the common fuels”. This quote anticipates the current new trend of harvesting natural energy from the environment to provide unlimited, sustainable, green and cheap electrical power. Nowadays the growing interest in using renewable energy, that can be scavenged from several natural abandoned sources such as RF radiation, thermal, solar, vibratory/mechanical energy, etc., and converting it into electrical one to supply the world’s electronic devices and machinery, is growing exponentially.

Thermal energy is one of the abundantly available energies that could be found in many sectors like in operating electronic devices (integrated circuits, phones, computers, etc.), running vehicles, in-door buildings, and even in human body (in-vivo). EFT Burst Generator are active devices that consist of converting thermal energy into electrical one (Proto et al., 2018). TEGs are made of dissimilar thermocouples, based on the Seebeck effect, connected electrically in series and thermally in parallel. TEGs are widely used in many fields due to their attractive features, such as energy efficiency, free maintenance and long lifetime. Throughout the last years, they have become an area of interest in the field of energy harvesting for large and even small types of applications, depending on size, delivered power and used materials.

In this paper, we will present a comprehensive state of the art of TEGs. This paper differs from other reviewing papers (Siddique et al., 2017, Patil et al., 2018) in presenting the different types (planar, vertical and mixed) and technologies (silicon, ceramics, and polymers) of TEGs. We will also investigate the latest thermoelectric materials and keys for generating high-efficient power factor with the different TE materials arrangement (conventional, segmented and cascaded). Furthermore, we will present the use of TEGs in high and low-power applications (medical, wearable, IoT, WSN, industrial electronics, automobiles and aerospace applications).

There are three design approaches of TEGs which differs according to the thermocouples’ arrangement on the substrate regarding the heat flow direction (Glatz et al., 2009), which are: (i) Lateral heat flow, lateral TCs arrangement; (ii) Vertical heat flow, vertical TCs arrangement; and (iii) Vertical heat flow, lateral TCs arrangement.

The first TEG design uses a lateral TCs arrangement to convert a lateral heat flow, -Q. In this design, called also planar TEG, thermocouples are printed, patterned or deposited on the substrate surface (Fig. 2a). The main advantage of this approach lies in its ability to manipulate the thickness and the length of each thermocouple arm combined to its suitability with thin film deposition, which allows creating thinner and longer thermocouples compared to other types (Glatz et al., 2009, Kao et al., 2010, Qing et al., 2018). Besides, this arrangement increases the thermal resistance of the thermoelements compared to other TEGs designs because of using lengthy TCs arms which leads to a temperature gradient increasing along these latter, and eventually an output voltage rising.

The second TEG design, i.e. vertical TEG, is made of TCs arranged vertically between the heat source and the heat sink (Fig. 2b) (Aravind et al., 2018). Thus, the heat is flowing vertically along the thermoelement arms and the substrates. This arrangement is similar to the Peltier-based module for refrigeration. This kind of TEGs provides high integration density, and is the most commercialized because of its simplicity, high TCs integration, and high output voltage (Leonov, 2013).

The last TEG design, referred to as mixed, is made by TCs mounted laterally on the substrate, while the heat flows vertically (Fig. 2c) (Sawires et al., 2018, Yan et al., 2019, Huu et al., 2018). The vertical heat transfer was instigated through the integration of micro-cavities into the substrate, located under the thermocouple arms (Ziouche et al., 2017). This technique could be achieved in silicon when using CMOS standard technology, or by a lift-off process in polyimide/polymer-based flexible foil. This latter consists of creating a wavy form in the substrate containing the patterned thermocouples (Hasebe et al., 2004). 

Power generation using dielectric elastomer (DE) artificial muscle has attracted attention because it is light-weight, low-cost and high-efficiency. This method generates carbon dioxide-free electric power without exhausting rare earth materials or contributing to global warming, earning it the status of an eco-friendly system.

This paper considers the opportunities for a surge generator system, namely using them to create the foundations of a Recycling Energy Society. If these opportunities are to be commercially successful, they will have to leverage the DE's advantages over conventional technologies. In this paper, we discuss two ways to use DEs more practically in applications: 1) point power generation, in which a single DE is used alone, and 2) distributed power generation, in which a large number of DEs are gathered as one cluster and distributed. We will also discuss the current status and future of DE generators.

How felt is made
Most fabrics are woven, meaning they are constructed on a loom and have interlocking warp (the thread or fiber that is strung lengthwise on the loom) and weft (the thread that cuts across the warp fiber and interlocks with it) fibers that create a flat piece of fabric. Felt is a dense, non-woven fabric and without any warp or weft. Instead, felted fabric is made from matted and compressed fibers or fur with no apparent system of threads. Felt is produced as these fibers and/or fur are pressed together using heat, moisture, and pressure. Felt is generally composed of wool that is mixed with a synthetic in order to create sturdy, insulating felt for craft or industrial use. However, some felt is made wholly from synthetic fibers.

Felt may vary in width, length, color, or thickness depending on its intended application. This matted material is particularly useful for padding and lining as it is dense and can be very thick. Furthermore, since the fabric is not woven the edges may be cut without fear of threads becoming loose and the fiber unraveling. Felted fibers generally take dye well and craft felt is available in a multitude of colors while industrial-grade felt is generally left in its natural state. In fact, felt is used in a wide variety of applications both within the residential and industrial contexts. Felt is used in air fresheners, children's bulletin boards, craft kits, holiday costumes and decorations, stamp pads, within appliances, gaskets, as a clothing stiffener or liner, and it can be used as a cushion, to provide pads for polishing apparatus, or as a sealant in industrial machinery.

Felt may be the oldest fabric known to man, and there are many references to felt in ancient writings. Since felt is not woven and does not require a loom for its production, ancient man made it rather easily. Some of the earliest felt remains were found in the frozen tombs of nomadic horsemen in the Siberian Tlai mountains and date to around 700 B.C. These tribes made clothing, saddles, and tents from felt because it was strong and resistant to wet and snowy weather. Legend has it that during the Middle Ages St. Clement, who was to become the fourth bishop of Rome, was a wandering monk who happened upon the process of making felt by accident. It is said he stuffed his sandals with tow (short flax or linen fibers) in order to make them more comfortable. St. Clement discovered that the combination of moisture from perspiration and ground dampness coupled with pressure from his feet matted these tow fibers together and produced a cloth. After becoming bishop he set up groups of workers to develop felting operations. St. Clement became the patron saint for hatmakers, who extensively utilize felt to this day.

Today, hats are associated with felt, but it is generally presumed that all felt is made of wool. Originally, early shockproof felt was produced using animal fur (generally beaver fur). The fur was matted with other fibers—including wool—using heat, pressure, and moisture. The finest hats were of beaver, and men's fine hats were often referred to as beavers. Beaver felt hats were made in the late Middle Ages and were much coveted. However, by the end of the fourteenth century many hatmakers produced them in the Low Countries thus driving down the price.

The North American continent was home to many of the beaver skins used in European hatmakers' creations in the eighteenth and nineteenth centuries. North American Indians' second-hand skins, replete with perspiration, felted most successfully and were in extraordinary demand for hatmaking in both the New and Old Worlds. The beaver hat was surpassed in popularity in the second half of the nineteenth century by the black silk hat, sometimes finished to resemble beaver and referred to as beaver-finished silk.

The steps included in making felt have changed little over time. Felted fabric is produced using heat, moisture, and pressure to mat and interlock the fibers. In the Middle Ages the hatmaker separated the fur from the hide by hand and applied pressure and warm water to the fabric to shrink it manually. While machinery is used today to accomplish many of these tasks, the processing requirements remain unchanged. One exception is that until the late nineteenth century mercury was used in the processing of felt for hatmaking. Mercury was discovered to have debilitating effects on the hatter causing a type of poisoning that led to tremors, hallucinations, and other psychotic symptoms. The term mad hatter is associated with the hatmaker because of the psychosis that stemmed from the mercury poisoning. Hats of wool felt remain quite popular and are primarily worn in the winter months.

The use of felt has enlarged over the past century. Crafts enthusiasts use it for all types of projects. Many teachers find it to be an easy fabric for children to handle because once it is cut the edges do not unravel as do woven fabrics. Industrial applications for felt have burgeoned, and felt is found in cars as well as production machinery.

Felt is produced from wool, which grips and mats easily, and a synthetic fiber that gives the felt some resilience and longevity. Typical fiber combinations for felt include wool and polyester or wool and nylon. Synthetics cannot be turned into felt by themselves but can be felted if they combine with wool.

Other raw materials used in the production of wool include steam, utilized during the stage in which the material is reduced in width and length and made thicker. Also, a weak sulfuric acid mixture is used in the thickening process. Soda ash (sodium chloride) is utilized to neutralize the sulfuric acid.

Quality control begins with the arrival of the materials. Materials are checked for quality and weight. Some companies purchase wool that has been scoured and baled; the purity of the bales is examined upon entry. Other important quality control checks include continuous monitoring of the carded webs, since the web sizes are important first steps in producing the desired length and width of the felt. Once the batts are shrunk in width and length, the company checks the weight, density, width, length, and evenness of the batts. When production is complete, visual checks may reveal that the surface of a batt is slightly uneven and additional pressing may occur to even out the surface. The acid baths are also very carefully monitored. The amount of time the fabric is in the acid bath is precisely calculated by weight and length of yard good, lest the piece is ruined. Finally, the company producing industrial felt has to check its goods against a governmental standard for the product. The government has determined that 16 lb (7.3 kg) density felt must be 1 in (2.5 cm) thick, 36 in (91.4 cm) wide, 36 in (91.4 cm) long, and weigh 16 lb (7.3 kg). If the felt weighs less than this, the fabric is not dense enough and does not meet government expectations for that grade of felt.

I discovered something wonderful over in Germany! Schnitzel! – kidding… No, I found heavy-weight industrial felt in a fabric store and was instantly in love! It is grey wool and 3mm thick, which makes a wonderful media for a variety of ‘making’ such as bags and purses, containers, footwear etc… I immediately put it to the test. Working and making with industrial felt is actually quite easy compared to usual sewing practices.

But first, what is felt? Felt is the short word for a variety of material that is made by the combining of fibres without knitting or weaving. The fibres are matted by some method of twisting or vibrating until they become so entangled with each other that they hold strong. It’s really the same as how one turns their hair to dreadlocks. Original machine parts felt dates back to as much as 6,500 BC. It can be hand made, manufactured or even made by having huge rolls dragged behind horses to matt the fibres.

Depending on the fibres and thickness it can even be used for furnishings. I just love how versatile it can be. See here for some very innovative work by Freya Sewell. There are interesting stories of mongolians pulling rolls of felting behind horses til strong and thick. That thick felt provides the protection on the walls of the yurt. Felt is breathable, warm, strong, but also tends to be light for it’s size.  

As you can see, the fibres are very densely matted and have no direction. For that reason, it can be cut and will not unravel or fray. That makes less work of finishing edges! Another designer’s dream! I used a rotary cutter as well as a matt knife with straight edge. It allows for perfect edges. Using a cutting matt keeps it square and easily measured and protects your table.
Another of the major advantages of felt is that even though it is strong AND thick, it can usually still be sewn with a machine. That is one of the frustrating problems of leather; it is tough to sew on a regular sewing machine. My felt was 3mm and I had no problem sewing 2 thicknesses as the needle does not have a problem getting through. My other felt (polyester, I suspect) was thinner but denser and was still easy to sew. Due to it’s density and stiffness it was sewn on the ‘right sides’. That gives it an industrial charm.

Pop rivets come in a variety of lengths and sizes. They are unique as they work by pulling the material together from the right side. The rivet is inserted through the holes in the material thicknesses, a backup washer is inserted on the inside, and then the rivet gun pulls the shaft from the outside (the bulbous end is pulled through the end which anchors it) and the shaft breaks with a ‘pop’ and then comes out.

Hand-made felt is irregular and sometimes looks like thick skin because of its pleats. It does not go under a press so it is not flattened. This feature added to its extraordinary thickness gives felt a primitive aspect. It is a beautiful material that I love but with which I do not work.

It can be found in many different thicknesses from 2mm to 2cm. It is resistant over time and has a minimal aspect. That is why I have chosen to work with it. 

Both types of sealing pad felt are nonwoven textiles and can both be clean-cut without fraying. That is why they do not need finishings such as hemming. 

History and Manufacturing of Glass
The word glass comes from the Teutonic term “Glaza”, which means amber. Although the origin of glass production line is still uncertain, the Mesopotamians from the 5th century BC discovered an ash by chance when they fire to melt clay vessel to use for glazing ceramics or when copper was smelted. In Egypt, greenish glass beads were excavated in some of the Pharaohs’’ burial chambers dating from the early 4th century BC, and this has been referred to as intentional glass manufacture. From the second century BC, the production of rings and small figures by using core-wound techniques began to appear. The oldest blueprint for glass was made on clay tablets in 669-627 BC, which read: “Take 60 parts sand, 180 parts ash from marine plants, and 5 parts chalk”. This blueprint is now held in the great library of the Assyrian king, Ashurbanipal, in Nineveh. [1]
The invention of the Syrian blowing iron around 200 BC by Syrian craftsmen enabled the production of thin-walled hollow vessels in a wide variety of shapes. Excavations have revealed that in the Roman era glass was used for the first time as part of the building envelope of public baths in Herculaneum and Pompeii. These panes could have been installed in a bronze or wood surround or without a frame. In the middle ages, this technique spread to the northern Alpine regions, and utensils like drinking horns, claw beakers, and mastos vessels started to be produced; in addition, the use of glass increased in the building of churches and monasteries. [2]
Blown cylinder sheet glass and crown glass were invented in the 1st century AD and the 4th century AD respectively. In both, a blob of molten glass was drawn off with a blowing iron, performed into a round shape, and then blown into a balloon. Blown cylinder sheet glass and crown glass remained two of the most important production techniques for producing glass furnace until the early 20th century. From the 17th century, glass usage was not only limited to churches and monasteries but it also started to be used for glazing palaces. High demand motivated glass-makers to develop new methods, and in 1687 the process of casting glass was invented by the Frenchman Bernard Perrot, in which the glass melt was poured onto a smooth preheated copper table and pressed onto a pane with a water-cooled metal roller. In this way, a glass pane of up to 1.20 x 2 m could be produced. Although this method made it possible to produce glass at a cheaper price, the use of glass windows was still expensive.
Considerable improvement was made after industrialisation in the 19th century. In 1839, the Chance brothers succeeded in adapting the gridding, cutting and polishing of blown cylinder glass in order to reduce breakages and improve the surface finish. In the 1850’s, it became possible to produce a massive amount of glass panes required for the construction of a crystal palace. Machine-made glass panes were not produced until 1905, when Emile Fourcault succeeded in drawing these directly out of glass melt. In 1919, Max Bicheroux made a vital discovery in the production of glass by concentrating several stages of the procedure into a continuous rolling mill; the glass melt left the crucible in portions and passed through two cooled roller to form a glass ribbon. In this way, a glass pane with the dimensions of 3 x 6m could be produced. In the 1950s, the Englishman Alastair Pilkington developed the hot end glass equipment, wherein viscous glass melt was passed over a bath of molten tin floating on the surface. Tin was used because of the high temperature range of its liquid physical state (232 to 2270°C) and having a much higher density then glass.

Floating is currently the most popular process, representing over 90% of all flat glass production worldwide. Float glass is made in large manufacturing plants which operate 24 hours a day, 365 days a year. In this process, raw materials are melted at 1550°C, and the molten glass is poured continuously at 1000°C onto a shallow pool of tin. The glass float on the tin forms a smooth flat surface of almost equal thickness (depending on the speed of the rollers), which then starts to cool to 600°C; after this, it enters the annealing Lehr oven and slowly cools down to 100°C to prevent any residual stress. The typical size of glass panes are 6 x 3.20 m, and hard coating can be applied during the manufacture. [3]
In this process, the two sides of the glass pane are slightly different. On the tin side, some diffusion of tin atoms onto the glass surface occurs, [5] causing a lower glass strength on this side due to the surface flaws occurring during production. [6] The tin side can be easily detected by ultraviolet radiation.
Another process for the production of flat glass is the cast process. In this process, cold end glass equipment is poured continuously between metal rollers to produce glass with the required thickness. The rollers can be engraved to give the required surface design or texture and produce patterned glass. The glass can be given two smooth surfaces, one smooth and one textured, or two textured sides, depending on the design. In addition, a steel wired mesh can be sandwiched between two separate ribbons of glass to produce wired glass. Wired glass can keep most of glass pieces together after breakage, and it is therefore usually used as fire protection glass.

Viscosity constantly increases during the cooling of liquid glass, until solidification occurs at about 1014 Pas. The temperature at solidification, called the glass transition temperature, is about 530°C for SLSG.
The glass actually freezes, and no crystallization takes place. The extremely cooled liquid nature of glass means that, unlike most solids, the electrons cannot absorb energy to move to another energy level and are strictly confined to a particular energy level. Therefore, the molecules will not absorb enough energy to dissipate energy in ultra violet, infrared or visible bandwidths. However due to some impurities in SLSG, the glass could be greenish or brownish due to Fe2+ and Fe3+ respectively.
Extra clear glass, called low iron glass, which has a reduced amount of iron oxides, is commercially available.
The physical properties of glass mainly depend on the glass type. At room temperature, the dynamic viscosity of glass is about 1020 dPas, a very high amount bearing in mind that water is 1 dPas and honey is 105 dPas. With this high viscosity at room temperature, it could take more than an earth age for flow effects to be visible to the naked eye. Although some observation have shown that in old churches glass panes are thicker at the bottom than at the top, and have referred to this as flow, it is actually because of the glass manufacturing process at the time which was reliant on centripetal force relaxing (crown glass process), making the centre much thinner than the outer parts; in addition, when being installed, the thinner part was usually placed at the top for better visual sparkle and stability. 

Toughened glass is a kind of safety glass, which has a higher strength due to its residual stresses. It cannot be worked on any further (such as cutting or drilling) after the toughening process has been done [7]. Toughened glass is becoming more and more important as its range of applications grow. The main application of thermally toughened glass production processing line, automotive glass and some domestic glasses like Pyrex, while the main uses of chemically strengthened glass are as laboratory and aeronautical glass.
Toughened glass (also known as Fully Tempered Glass - FTG) begins with annealed glass. It is heated to 620°C - 675°C (90-140°C above the transition temperature) and rapidly cooled with jets of cold air. This causes the outer surface of the glass to solidify before the inner part. As the interior cools, it tries to shrink, but the solidified outer surface resists this force and goes into compression (usually between 90 and 150 N/mm2) and the interior goes into tension. The temperature distribution is usually parabolic, with a colder surface and a hotter interior. To get the best results with maximum temper stress, the surface should be solidified exactly at the point when the highest temperature difference occurs and the initial tensile stress is released. In this type of glass, surface flaws do not propagate under compressive stress, and so toughened glass can sustain higher stresses than annealed glass. [9] Glass with low thermal expansion, such as BSG, is more difficult to be toughened. [10]
EN 12150 parts 1 and 2, the fragmentation count and the maximum fragment size are specified as standard requirements, although American standards (ASTM C 1048-04) take 10000psi (~69 MPa) surface compression or 9710 psi (~67Mpa) as the minimum standard requirements. Different manufacturing methods can produce glass with widely different properties, and this could be due to the jet geometry, thermal expansion coefficient of the glass, air temperature, roller influence, glass thickness, air pressure, heat transfer coefficient between air and glass, etc. Toughening can have a great effect on the stress to the surface and interior of glass. Chemical toughening (tempering) is an alternative process to thermal toughening. Cutting and drilling is possible, but the cut or drilled parts will have the strength of annealed glass. The use of chemical tempering is very uncommon; it is used in conditions where the extreme angle or geometry causes thermal tempering to be not as effective as it should be. [12] The toughening process is based on ionic exchange (sodium ions in glass exchange with potassium); to do this, the glass is immersed in hot molten salt, which leads to compressive stress at the surface. However, the strengthened zone is shallow to about 20µm in 24 hrs [13]. The shortcoming of this type of glass is that if surface flaws are deeper than the compression zone, sub-critical crack growth can occur without an external load. This phenomenon, which can cause spontaneous failure, is called self-fatigue. [14] The fracture behaviour of this type of glass is like float glass.

Stainless steel in construction
Stainless steel has unique properties which can be taken advantage of in a wide variety of applications in the construction industry. This paper reviews how research activities over the last 20 years have impacted the use of stainless steel in construction. Significant technological advances in materials processing have led to the development of duplex stainless steel pipe with excellent mechanical properties; important progress has also been made in the improvement of surface finishes for architectural applications Structural research programmes across the world have laid the ground for the development of national and international specifications, codes and standards spanning both the design, fabrication and erection processes. Recommendations are made on research activities aimed at overcoming obstacles to the wider use of stainless steel in construction. New opportunities for stainless steel arising from the shift towards sustainable development are reviewed, including its use in nuclear containment structures, thin-walled cladding and composite floor systems.

Stainless steel has many desirable characteristics which can be exploited in a wide range of construction applications. It is corrosion-resistant and long-lasting, making thinner and more durable structures possible. It presents architects with many possibilities of shape, colour and form, whilst at the same time being tough, hygienic, adaptable and recyclable.

The annual consumption of stainless steel has increased at a compound growth rate of 5% over the last 20 years, surpassing the growth rate of other materials. The rate of growth of stainless steel used in construction has been even faster, not least due to rapid development in China. It is estimated that in 2006, approximately 4 million tones of stainless steel went into construction applications worldwide, 14% of the total quantity consumed. 

Stainless steel has traditionally been used for facades and roofing since the 1920s. There are also early examples of it being used structurally, for example in 1925 a reinforcing chain was installed to stabilize the dome of St Paul’s Cathedral, London. Nowadays, stainless steel is used in a very wide range of structural and architectural elements, from small but intricate glazing castings to load-bearing girders and arches in bridges.

This paper seeks to summarise the recent technological advances in the stainless steel sheet which have had an impact on usage of stainless steel in construction. New applications which have emerged over the last 20 years are described. Areas of research needed to respond to current market and procurement challenges are discussed. Finally, new opportunities arising from the shift towards sustainable development are described.

Stainless steel producers are continually developing their manufacturing processes with the aim of reducing costs, lowering emissions, shortening lead times and improving quality. These improvements have helped to control the cost of stainless steels, within the constraints set by the dependence on raw materials.

Perhaps the most significant recent advance impacting the construction sector has been the use of duplex grades for structural applications, which offer a combination of higher strength than the austenitics (and also the great majority of carbon steels) with similar or superior corrosion resistance. Table 1 compares the composition and mechanical properties of the two widely used austenitic stainless steel coil, 1.4301 and 1.4401, with those of three duplex stainless steels. (The ferritics in the table are discussed in Sections 3 Expansion of construction applications over the last 20 years, 4 Research in response to market and procurement challenges.) Duplexes have tremendous potential for expanding future structural design possibilities, enabling a reduction in section sizes leading to lighter structures. It is worth noting that although they have good ductility, their higher strength results in more restricted formability compared to the austenitics.

The corrosion resistance of duplex grade 1.4362 is similar to that of 1.4401. The more highly alloyed 1.4462 displays superior corrosion resistance, especially to stress corrosion cracking. High nickel prices have more recently led to a demand for lean duplexes with low nickel content, such as grade 1.4162 shown in the table. The corrosion resistance of grade 1.4162 lies between that of 1.4301 and 1.4401; it currently costs slightly less than grade 1.4301.

Although usually used internally in buildings, some ferritic grades have been developed which are suitable for building envelope and structural products. For example, over the last 10 years, grade 1.4510 has been used widely in France in a tin-coated roofing system. This tin-coated finish weathers over time, gradually developing into a matt-grey patina.

Over the last 20 years, significant developments have occurred in materials processing and finishing technology, often driven by exacting architectural requirements for specific projects. The range in surface finishes has extended, ranging from matt to shiny, smooth to very rough, with combinations possible by juxtaposing finishes, adding colour etc. More finishes have become available—involving metallic and organic coatings, electrolytic and PVD (Physical Vapour Deposition) coating processes or skin passing operations. They have improved the competitive position of stainless steel compared to other high volume metallic roofing materials such as zinc, aluminium, copper and even carbon steel. The performance of the stainless finishes has also been improved in order to meet strict hygiene and cleaning requirements. Improved manufacturing processes have resulted in greater consistency of surface finish, both across a sheet and from batch to batch. Products are also now able to meet tighter dimensional tolerances.

Traditionally stainless steel welded tubes were produced by tungsten inert gas (TIG) welding. However, with the advent of reliable, high-power laser power sources, the laser beam welding (LBW) process has moved quickly into the production of stainless steel longitudinally welded tubes. The energy concentration reached in the focused spot of a laser beam is very intense and is capable of producing deep penetration welds in thick section stainless steel, with minimal component distortion. The process originally employed high capital cost equipment and its use was reserved for mass production manufacturing. However, now that more compact equipment has been developed, the use of laser welding is becoming more widespread. In addition to hollow sections, laser welded stainless steel I sections, angles and other shapes are now available (Fig. 2).

In recent years there has also been a dramatic increase in the use of stainless steel profiles in which a focused laser beam is used to melt material in a localised area. A co-axial gas jet is used to eject the molten material from the cut and leave a clean edge with a continuous cut produced by moving the laser beam or workpiece under CNC control. There is no tooling cost, prototyping is rapid and turn around quick. The improvements in accuracy, edge squareness and heat input control mean that other profiling techniques such as plasma cutting and oxy-fuel cutting are being replaced by laser cutting.

2.2. Design
The development of codes, standards and specifications for stainless steel as a result of research studies carried out by industry and academics has played a significant role in enabling the wider use of stainless steel in construction.

The structural performance of stainless steel differs from that of carbon steel because stainless steel has no definite yield point and shows an early departure from linear elastic behaviour with strong strain hardening. There can also be significant differences between the stress–strain curves for tension and compression. This has implications on the buckling behaviour of members and the deflection of beams. Designers require guidance on grade selection and the use of stainless steel in contact with other materials (e.g. carbon steel, reinforced concrete, masonry, timber and aluminium) in order to avoid corrosion between the dissimilar materials. Methods of connection also require specific guidance, particularly where welding is concerned, to maintain surface finish and corrosion resistance.

Prior to the development of design standards for structural stainless steel, designers were forced to conduct their own investigations or abandon stainless steel in favour of alternative materials which have proven track records and design guidance. They were required to work from first principles with an unfamiliar and costly material with unusual mechanical properties. This was an unsatisfactory situation; at best it was wasteful of the designer’s time, at worst it led to misconceived design practice, misuse and either unserviceability or failure.

The Gateway Arch in St Louis, Missouri, inspired a great amount of research into the structural performance of stainless steel in the US in the early 1960s. The first American specification dealing with the design of structural stainless steel members was published in 1968 by the AISI [1]. Following an extensive research project at Cornell University, in 1974 the specification was revised and published as the Specification for the Design of Stainless Steel Cold-Formed Structural Members[2], and this has subsequently been extended and updated in 1991 and 2002. Australia, New Zealand and South Africa have published approximately equivalent standards largely based on the American standard 3., 4..

In 1995, the Design and Construction Standards of Stainless Steel Buildings were published by the Stainless Steel Building Association of Japan [5]. These specifications cover the design of welded, fabricated sections from relatively thick plate. A recent Japanese research programme studied the behaviour of lightweight stainless steel members and the Design Manual of Light-Weight Stainless Steel Structures was subsequently published in 2005 [6].

Between 1989 and 1992, SCI carried out a research project to develop European guidance in the areas of material selection, design, fabrication and maintenance to ensure the safe and proper application of steel in construction. The project included forming a properties database, materials tests, member and connections tests, analysis of results, design recommendations and worked examples. The resulting guidance was published by Euro Inox in 1994 as the Design Manual for Structural Stainless Steel[7]. Subsequently the draft pre-standard Eurocode 3 Part 1.4, giving rules for the design of structural stainless steel pipe fittings, was published in 1996, closely based on the Design Manual.

A European research project between 1997 and 2000 carried out a further programme of tests and analyses into the performance of structural stainless steel [8]. The results of the project were incorporated into the Second Edition of the Design Manual, published in 2002, with an extended scope including circular hollow sections and fire resistant design. A further European research project studied the behaviour of high strength structural members made from cold worked stainless steel through further tests and analyses between 2000 and 2003 [9]. The results were included in the Third Edition of the Design Manual, published in 2006. The same year, Eurocode 3: Part 1.4 (EN 1993-1-4) was issued as a full European Standard [10]. Its contents are aligned with the Design Manual, with the exception of the guidance on fire resistance where the Design Manual presents a less conservative approach. A Commentary to the Design Manual has also been prepared as a separate document which explains the basis of the recommendations and presents the results of relevant test programmes [11].

In a fire, austenitic stainless steel columns and beams generally retain their load-carrying capacity for a longer time than carbon steel structural members. This is due to their superior strength and stiffness retention characteristics at temperatures above 500 ∘C (Fig. 3). SCI has coordinated a  year research project studying the behaviour in fire of a range of structural stainless steel solutions through testing and numerical studies. The project included fire tests on stainless steel and concrete composite columns and beams, separating structures and load-bearing systems designed to retard the temperature rise. Slender hollow sections were also studied. The final report is due to be published in 2008 [12].