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Authors: Suhaib Salahuddin Alzubair Suliman

Abstract:

This paper examines the mechanical strength of different binders including pure ordinary Portland cement (OPC) and others having OPC supplemented by two maximum sizes of waste glass powder (GP) of 75-μm and 150μm. Chemical analysis of the GPs using PCEDX test analysis has revealed it silica (SiO2 ) content % is 86.883 and Calcium oxide (CaO) is 12.203%while there are traces of other impurities . Furthermore, the specific gravity of GP was measured. The experiments have been conducted on 63 specimens mortar made with standard sand with 20%,25%, and 30% of GP levels of substituting OPC. The specimens are tested at 3, 7 and 28 days for compressive strength and flexural strength. The specimens made with maximum GP size of 75-μm have outperformed the control OPC mortar at 28 days test age than size 150-μm at various replacement levels. In addition to that, the mechanical strengths were evaluated compressive strength and flexural strength tests were conducted for GPs. The findings from this study indicated that the mortars modified with GP 75μm and replacement ratio of 20% showed an improvement in compressive strength and flexural strength compared to the control mortar at the 28 days of curing with significant development between 7 and 28 days. Mortar with GP size 75-μm containing 30% & 20% replacement of cement have exhibited the highest flexural strength among all mortar mixtures. The improvement in the mechanical strength of the mortars modified with GP can be attributed to the pozzolanic property of GPs, which leads to a more densified microstructure and improved interfacial bonding between sand and cement paste matrix in mortars.

Keywords: glass powder, pozzolana, compressive strength, flexural strength, mortar

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Authors: A. Umar, A. Tamimi

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Development of new types of concrete with improved performance is a very important issue for the whole building industry. The development is based on the optimization of the concrete mix design, with an emphasis not only on the workability and mechanical properties but also to the durability and the reliability of the concrete structure in general. Self-compacting concrete (SCC) is a high-performance material designed to flow into formwork under its own weight and without the aid of mechanical vibration. At the same time it is cohesive enough to fill spaces of almost any size and shape without segregation or bleeding. Construction time is shorter and production of SCC is environmentally friendly (no noise, no vibration). Furthermore, SCC produces a good surface finish. Despite these advantages, SCC has not gained much local acceptance though it has been promoted in the Middle East for the last ten to twelve years. The reluctance in utilizing the advantages of SCC, in Bahrain, may be due to lack of research or published data pertaining to locally produced SCC. Therefore, there is a need to conduct studies on SCC using locally available material supplies. From the literature, it has been observed that the use of viscosity modifying admixtures (VMA), micro silica and glass fibers have proved to be very effective in stabilizing the rheological properties and the strength of fresh and hardened properties of self-compacting concrete (SCC). Therefore, in the present study, it is proposed to carry out investigations of SCC with combinations of various dosages of VMAs with and without micro silica and glass fibers and to study their influence on the properties of fresh and hardened concrete.

Keywords: self-compacting concrete, viscosity modifying admixture, micro silica, glass fibers

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Authors: Yogesh S. Patel

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Novel polyimides were synthesized by Diels–Alder polymerization. Bisfuran was reacted with a couple of bismaleimides containing diglycidyl ether of bisphenol-A and F (epoxy) segment to obtain Diels–Alder polyadducts. Polyadducts were then aromatized and imidized (i.e. cyclized) through carboxylic and amide groups to afford polyimides. Synthesized polyadducts and polyimides were characterized by elemental analysis, spectral features, the number of average molecular weight (Mn) and thermal analysis. The ‘in situ’ glass fiber reinforced composites were prepared and characterized by mechanical, electrical, and chemical properties. These properties were compared with the other reported polyimides. All the composites showed good mechanical and electrical properties and good resistance to organic solvents and mineral acids.

Keywords: Diels-Alder reaction, bisfuran, bismaleimides, polyimide

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Authors: Innocent Kafodya, Guijun Xian

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This paper presents effects of distilled water, seawater and sustained bending strains of 30% and 50% ultimate strain at room temperature, on the durability of unidirectional pultruded carbon fiber reinforced polymer (CFRP) plates. In this study, dynamic mechanical analyzer (DMA) was used to investigate the synergic effects of the immersions and bending strains on the visco-elastic properties of (CFRP) such as storage modulus, tan delta and glass transition temperature. The study reveals that the storage modulus and glass transition temperature increase while tan delta peak decreases in the initial stage of both immersions due to the progression of curing. The storage modulus and Tg subsequently decrease and tan delta increases due to the matrix plasticization. The blister induced damages in the unstrained seawater samples enhance water uptake and cause more serious degradation of Tg and storage modulus than in water immersion. Increasing sustained bending decreases Tg and storage modulus in a long run for both immersions due to resin matrix cracking and debonding. The combined effects of immersions and strains are not clearly reflected due to the statistical effects of DMA sample sizes and competing processes of molecular reorientation and postcuring.

Keywords: pultruded CFRP plate, bending strain, glass transition temperature, storage modulus, tan delta

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Authors: Selin Kunc, Srinivas Koushik Gundimeda, John A. Gallagher, Roselita Fragoudakis

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This study investigates the behavior of Glass Fiber Reinforced Plastic (GFRP) laminated beams additionally reinforced with piezoelectric fibers. The electromechanical behavior of piezoelectric materials coupled with high strength/low weight GFRP laminated beams can have significant application in a wide range of industries. Energy scavenging through mechanical vibrations is the focus of this study, and possible applications can be seen in the automotive industry. This study examines the behavior of such composite laminates using Classical Lamination Theory (CLT) under three-point bending conditions. Fiber orientation is optimized for the desired stiffness and deflection that yield maximum energy output. Finite element models using ABAQUS/CAE are verified through experimental testing. The optimum stacking sequences examined are [0o]s, [ 0/45o]s, and [45/-45o]s. Results show the superiority of the stacking sequence [0/45o]s, providing higher strength at a lower weight, and maximum energy output. Furthermore, laminated GFRP beams additionally reinforced with piezoelectric fibers can be used under bending to not only replace metallic component while providing similar strength at a lower weight but also provide an energy output.

Keywords: classical lamination theory (CLT), energy scavenging, glass fiber reinforced plastics (GFRP), piezoelectric fibers

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Authors: Ahmed M. Seyam, Rita Nemes

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In this study, the influence of elevated temperature and concrete age on the compressive strength of concrete produced by normal quartz aggregate, expanded clay, expanded glass, crushed andesite and crushed clay bricks aggregates were investigated. For this purpose, six different mixtures were prepared by 100% replacement of the coarse aggregate. The specimens were cured in water for seven days, then kept in the laboratory for 120 days and 240 days. The concrete specimens were heated in an electric furnace up to 200, 400, 600, 800, and 1000 °C and kept at these temperatures for two hours heating, then for 24 hours cooling. The residual compressive strength of the specimens was measured. The results showed that, the elevated temperature induces a significant decrease in a compressive strength in both normal weight and lightweight aggregate concrete, by comparing the behavior of different mixes, in all cases, the strength of the specimens containing crushed andesite aggregates showed a better performance for compressive strength after exposure to elevated temperatures over 800 °C, while the specimens containing expanded glass showing the least residual strength after subjected to elevated temperature; moreover the age of the concrete in all mixes has also been an effective factor, the behavior of the concrete strength loss by increasing heating temperature was not changed but the strength results showing the better performance and higher compressive strength in both ambient and elevated temperature.

Keywords: elevated temperature, concrete age, compressive strength, expanded clay, expanded glass, crushed andesite, crushed clay bricks

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Authors: Chung-Hyeon Ryu, Do-Hyoung Kim, Hak-Sung Kim

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As the use of the composites was increased, the detecting method of hidden damages which have an effect on performance of the composite was important. Terahertz (THz) spectroscopy was assessed as one of the new powerful nondestructive evaluation (NDE) techniques for fiber reinforced composite structures because it has many advantages which can overcome the limitations of conventional NDE techniques such as x-rays or ultrasound. The THz wave offers noninvasive, noncontact and nonionizing methods evaluating composite damages, also it gives a broad range of information about the material properties. In additions, it enables to detect the multiple-delaminations of various nonmetallic materials. In this study, the pulse type THz spectroscopy imaging system was devised and used for detecting and evaluating the hidden delamination in the glass fiber reinforced plastic (GFRP) composite laminates. The interaction between THz and the GFRP composite was analyzed respect to the type of delamination, including their thickness, size and numbers of overlaps among multiple-delaminations in through-thickness direction. Both of transmission and reflection configurations were used for evaluation of hidden delaminations and THz wave propagations through the delaminations were also discussed. From these results, various hidden delaminations inside of the GFRP composite were successfully detected using time-domain THz spectroscopy imaging system and also compared to the results of C-scan inspection. It is expected that THz NDE technique will be widely used to evaluate the reliability of composite structures.

Keywords: terahertz, delamination, glass fiber reinforced plastic composites, terahertz spectroscopy

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Authors: Fida Isam Abdulhafiz

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Traditional vernacular architecture in the United Arab Emirates constituted namely of adobe houses with a limited number of openings in their facades. The thick mud and rubble walls and wooden window screens protected its inhabitants from the harsh desert climate and provided them with privacy and fulfilled their comfort zone needs to an extent. However, with the rise of the immediate post petroleum era reinforced concrete villas with glass and steel technology has replaced traditional vernacular dwellings. And more load was put on the mechanical cooling systems to ensure the satisfaction of today’s more demanding doweling inhabitants. However, In the early 21at century professionals started to pay more attention to the carbon footprint caused by the built constructions. In addition, many studies and innovative approaches are now dedicated to lower the impact of the existing operating buildings on their surrounding environments. The UAE government agencies started to regulate that aim to revive sustainable and environmental design through Local and international building codes and urban design policies such as Estidama and LEED. The focus in this paper is on the reduction of the emissions resulting from the use of energy sources in the cooling and heating systems, and that would be through using innovative screen designs and façade solutions to provide a green footprint and aesthetic architectural icons. Screens are one of the popular innovative techniques that can be added in the design process or used in existing building as a renovation techniques to develop a passive green buildings. Preparing future architects to understand the importance of environmental design was attempted through physical modelling of window screens as an educational means to combine theory with a hands on teaching approach. Designing screens proved to be a popular technique that helped them understand the importance of sustainable design and passive cooling. After creating models of prototype screens, several tests were conducted to calculate the amount of Sun, light and wind that goes through the screens affecting the heat load and light entering the building. Theory further explored concepts of green buildings and material that produce low carbon emissions. This paper highlights the importance of hands on experience for student architects and how physical modelling helped rise eco awareness in Design studio. The paper will study different types of façade screens and shading devices developed by Architecture students and explains the production of diverse patterns for traditional screens by student architects based on sustainable design concept that works properly with the climate requirements in the Middle East region.

Keywords: building’s screens modeling, façade design, sustainable architecture, sustainable dwellings, sustainable education

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Authors: Mohammadjavad Mahdavinejad, Hadi Yazdi

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The greatest influence we have from the world is shaped through the visual form, thus light is an inseparable element in human life. The use of daylight in visual perception and environment readability is an important issue for users. With regard to the hazards of greenhouse gas emissions from fossil fuels, and in line with the attitudes on the reduction of energy consumption, the correct use of daylight results in lower levels of energy consumed by artificial lighting, heating and cooling systems. Windows are usually the starting points for analysis and simulations to achieve visual comfort and energy optimization; therefore, attention should be paid to the orientation of buildings to minimize electrical energy and maximize the use of daylight. In this paper, by using the Design Builder Software, the effect of the orientation of an 18m²(3m*6m) room with 3m height in city of Tehran has been investigated considering the design constraint limitations. In these simulations, the dimensions of the building have been changed with one degree and the window is located on the smaller face (3m*3m) of the building with 80% ratio. The results indicate that the orientation of building has a lot to do with energy efficiency to meet high-performance architecture and planning goals and objectives.

Keywords: daylight, window, orientation, energy consumption, design builder

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Authors: Mohammad Arifin, Huda Abdullah, Norshafadzila Mohammad Naim

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The fabricated PANI-(SnO₂, ZnO)/rGO nanocomposite thin films for the E. coli bacteria sensor were investigated. The nanocomposite thin films were prepared by the sol-gel method and deposited on the glass substrate using the spin-coating technique. The internal structure and surface morphology of the thin films have been analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM). The optical properties of the films were investigated by UV-Vis spectroscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR). The sensitivity performance was identified by measuring the changing conductivity before and after the incubation of E. coli bacteria using current-voltage (I-V) and cyclic voltammetry (C-V) measurements.

Keywords: PANI-(SnO₂, ZnO)/rGO, nanocomposite, bacteria sensor, thin films

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Authors: Jonathan Galvan-Colin, Ariel Valladares, Renela Valladares, Alexander Valladares

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Both porous materials and bulk metallic glasses have been studied due to their potential applications and their exceptional physical and chemical properties. However, each material presents certain drawbacks which have been thought to be overcome by generating bulk metallic glass foams (BMGF). Although some experimental reports have been performed on multicomponent BMGF, still no ab initio works have been published, as far as we know. We present an approach based on the expanding lattice (EL) method to generate binary amorphous nanoporous Cu64Zr36. Starting from two different configurations: a 108-atom crystalline cubic supercell (cCu64Zr36) and a 108-atom amorphous supercell (aCu64Zr36), both with an initial density of 8.06 g/cm3, we applied EL method to halve the density and to get 50% of porosity. After the lattice expansion the supercells were subject to ab initio molecular dynamics for 500 steps at constant room temperature. Then, the samples were geometry-optimized and characterized with the pair and radial distribution functions, bond-angle distributions and a coordination number analysis. We found that pores appeared along specific spatial directions different from one to another and that they differed in size and form as well, which we think is related to the initial structure. Due to the lack of experimental counterparts our results should be considered predictive and further studies are needed in order to handle a larger number of atoms and its implication on pore topology.

Keywords: ab initio molecular dynamics, bulk mettalic glass, porous alloy

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Authors: Ekpekpo Arthur

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Thin films can either be conductive or dielectric (non-conductive). It is formed through atom/molecules state or formed after decomposing the materials into atomic/molecular scale by physical or chemical processes. In this study, thin films of Lead Sulphide were deposited on glass substrate prepared from lead acetate and thiourea solution using chemical bath deposition (CBD). The glass slides were subjected to the pretreatment by soaking them in a solution of 50% sulphuric acid and 50% nitric acid. Lead sulphide was deposited at different parameters such as deposition time and temperature. The optical properties of the thin films were determined from spectroscopy measurements of absorbance and reflectance. Optical studies show that the band gap of lead sulphide ranges between 0.41 eV to 300K.

Keywords: lead sulphide, spectroscopy, absorbance, reflectance

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Authors: Abhisek Dash

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This study had three neural networks, one for number segmentation, one for number detection and one for number recognition all of which are coupled to one another. All networks were trained on the MNIST dataset and were convolutional. It was assumed that the images had lighter background and darker foreground. The segmentation network took 28x28 images as input and had sixteen outputs. Segmentation training starts when a dark pixel is encountered. Taking a window(7x7) over that pixel as focus, the eight neighborhood of the focus was checked for further dark pixels. The segmentation network was then trained to move in those directions which had dark pixels. To this end the segmentation network had 16 outputs. They were arranged as “go east”, ”don’t go east ”, “go south east”, “don’t go south east”, “go south”, “don’t go south” and so on w.r.t focus window. The focus window was resized into a 28x28 image and the network was trained to consider those neighborhoods which had dark pixels. The neighborhoods which had dark pixels were pushed into a queue in a particular order. The neighborhoods were then popped one at a time stitched to the existing partial image of the number one at a time and trained on which neighborhoods to consider when the new partial image was presented. The above process was repeated until the image was fully covered by the 7x7 neighborhoods and there were no more uncovered black pixels. During testing the network scans and looks for the first dark pixel. From here on the network predicts which neighborhoods to consider and segments the image. After this step the group of neighborhoods are passed into the detection network. The detection network took 28x28 images as input and had two outputs denoting whether a number was detected or not. Since the ground truth of the bounds of a number was known during training the detection network outputted in favor of number not found until the bounds were not met and vice versa. The recognition network was a standard CNN that also took 28x28 images and had 10 outputs for recognition of numbers from 0 to 9. This network was activated only when the detection network votes in favor of number detected. The above methodology could segment connected and overlapping numbers. Additionally the recognition unit was only invoked when a number was detected which minimized false positives. It also eliminated the need for rules of thumb as segmentation is learned. The strategy can also be extended to other characters as well.

Keywords: convolutional neural networks, OCR, text detection, text segmentation

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Authors: Maja Stefanovska, Svetlana Risteska, Blagoja Samakoski, Gari Maneski, Biljana Kostadinoska

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Aim of this work is to determine the theoretical and experimental properties of filament wound glass fiber/epoxy resin composite pipes with different winding design subjected under bending. For determination of bending strength of composite samples three point bending tests were conducted according to ASTM D790 standard. Good correlation between theoretical and experimental results has been obtained, where sample No4 has shown the highest value of bending strength. All samples have demonstrated matrix cracking and fiber failure followed by layers delamination during testing. Also, it was found that smaller winding angles lead to an increase in bending stress. From presented results good merger between glass fibers and epoxy resin was confirmed by SEM analysis.

Keywords: bending properties, composite pipe, winding design, SEM

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Authors: Jongho Park, Taekyun Kim, Jungbhin You, Sungnam Hong, Sun-Kyu Park

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Due to the aging of bridges, increasing of maintenance costs and decreasing of structural safety is occurred. The steel corrosion of reinforced concrete bridge is the most common problem and this phenomenon is accelerating due to abnormal weather and increasing CO₂ concentration due to climate change. To solve these problems, composite members using textile have been studied. A textile reinforced concrete can reduce carbon emissions by reduced concrete and without steel bars, so a lot of structural behavior studies are needed. Therefore, in this study, textile reinforced concrete beam was made and flexural test was performed. Also, the change of flexural strength according to the prestressing was conducted. As a result, flexural strength of TRC with prestressing was increased compared and flexural behavior was shown as reinforced concrete.

Keywords: AR-glass, flexural strength, prestressing, textile reinforced concrete

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Authors: Benchalak Muangmeesri

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Glazes ceramics are ceramic materials produced through controlled crystallization of a parent glass. The great variety of compositions and the possibility of developing special micro structures with specific technological properties have allowed glass ceramic materials to be used in a wide range of applications. At the same time, glazes ceramics need to improvement in the mechanical and chemical properties of glazed. The pick and place station is equipped with a three-axis module. test piece housings placed on the vacuum are detected module picks up a test piece insert from the slide and places it on the test piece housing. Overall, glazes ceramics are compared with automatically and manually of speed and position control. The handling modules of automatic transfer are a new generation of high speed and precision then these color results from absorption and thickness than manual is also included.

Keywords: glaze, PID control, pick and place, ceramic

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Authors: P. Abachi, S. Karami, K. Purazrang

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The amorphous reinforcements (metallic glasses) can be considered as promising options for reinforcing light-weight aluminum and its alloys. By using the proper type of reinforcement, one can overcome to drawbacks such as interfacial de-cohesion and undesirable reactions which can be created at ceramic particle and metallic matrix interface. In this work, the Zr-based amorphous phase was produced via mechanical milling of elemental powders. Based on Miedema semi-empirical Model and diagrams for formation enthalpies and/or Gibbs free energies of Zr-Cu amorphous phase in comparison with the crystalline phase, the glass formability range was predicted. The composite was produced using the powder mixture of the aluminum and metallic glass and spark plasma sintering (SPS) at the temperature slightly above the glass transition Tg of the metallic glass particles. The selected temperature and rapid sintering route were suitable for consolidation of an aluminum matrix without crystallization of amorphous phase. To characterize amorphous phase formation, X-ray diffraction (XRD) phase analyses were performed on powder mixture after specified intervals of milling. The microstructure of the composite was studied by optical and scanning electron microscope (SEM). Uniaxial compression tests were carried out on composite specimens with the dimension of 4 mm long and a cross-section of 2 ˟ 2mm2. The micrographs indicated an appropriate reinforcement distribution in the metallic matrix. The comparison of stress–strain curves of the consolidated composite and the non-reinforced Al matrix alloy in compression showed that the enhancement of yield strength and mechanical strength are combined with an appreciable plastic strain at fracture. It can be concluded that metallic glasses (amorphous phases) are alternative reinforcement material for lightweight metal matrix composites capable of producing high strength and adequate ductility. However, this is in the expense of minor density increase.

Keywords: aluminum matrix composite, amorphous phase, mechanical alloying, spark plasma sintering

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Authors: Revytia Tanera

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This research is a pilot study to examine the rise of selfie trend in dealing with individual self representation and identity building in social media. The symbolic interactionism theory is used as the concept of the desired self image, and Cooley’s looking glass-self concept is used to analyze the mechanical reflection of ourselves; how do people perform their “digital self” in social media. In-depth interviews were conducted in the study with a non-random sample who owns a smartphone with a front camera feature and are active in social media. This research is trying to find out whether the selfie trend brings any influence on identity building on each individual. Through analysis of interview results, it can be concluded that people take selfie photos in order to express themselves and to boost their confidence. This study suggests a follow up and more in depth analysis on identity and self representation from various age groups.

Keywords: self representation, selfie, social media, symbolic interaction, looking glass-self

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Authors: F. Dabir, R. Sarraf-Mamoory, N. Riahi-Noori

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In this work, a nanostructured TiO2 layer was coated onto a FTO-less glass substrate using screen printing technique for back contact DSSC application. Then, titanium nitride thin film was applied on TiO2 layer by plasma assisted chemical vapor deposition (PACVD) as charge collector layer. The microstructure of prepared TiO2 layer was characterized by SEM. The sheet resistance, microstructure and elemental composition of titanium nitride thin films were analysed by four point probe, SEM, and EDS, respectively. TiO2 layer had porous nanostructure. The EDS analysis of TiN thin film showed presence of chlorine impurity. Sheet resistance of TiN thin film was 30 Ω/sq. With respect to the results, PACVD TiN can be a good candidate as a charge collector layer in back contacts DSSC.

Keywords: TiO2, TiN, charge collector, DSSC

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Authors: Carlos Vera, Tetyana Baydyk, Ernst Kussul, Graciela Velasco, Miguel Aparicio

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This article describes the Random Subspace Neural Classifier (RSC) for the recognition of meteors in the night sky. We used images of meteors entering the atmosphere at night between 8:00 p.m.-5: 00 a.m. The objective of this project is to classify meteor and star images (with stars as the image background). The monitoring of the sky and the classification of meteors are made for future applications by scientists. The image database was collected from different websites. We worked with RGB-type images with dimensions of 220x220 pixels stored in the BitMap Protocol (BMP) format. Subsequent window scanning and processing were carried out for each image. The scan window where the characteristics were extracted had the size of 20x20 pixels with a scanning step size of 10 pixels. Brightness, contrast and contour orientation histograms were used as inputs for the RSC. The RSC worked with two classes and classified into: 1) with meteors and 2) without meteors. Different tests were carried out by varying the number of training cycles and the number of images for training and recognition. The percentage error for the neural classifier was calculated. The results show a good RSC classifier response with 89% correct recognition. The results of these experiments are presented and discussed.

Keywords: contour orientation histogram, meteors, night sky, RSC neural classifier, stars

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Authors: Shrawan Baghel, Helen Cathcart, Biall J. O'Reilly

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Amorphous drug formulations have great potential to enhance solubility and thus bioavailability of BCS class II drugs. However, the higher free energy and molecular mobility of the amorphous form lowers the activation energy barrier for crystallization and thermodynamically drives it towards the crystalline state which makes them unstable. Accurate determination of the crystallization tendency/kinetics is the key to the successful design and development of such systems. In this study, dipyridamole (DPM) and cinnarizine (CNZ) has been selected as model compounds. Thermodynamic fragility (m_T) is measured from the heat capacity change at the glass transition temperature (Tg) whereas dynamic fragility (m_D) is evaluated using methods based on extrapolation of configurational entropy to zero 〖(m〗_(D_CE )), and heating rate dependence of Tg 〖(m〗_(D_Tg)). The mean relaxation time of amorphous drugs was calculated from Vogel-Tammann-Fulcher (VTF) equation. Furthermore, the correlation between fragility and glass forming ability (GFA) of model drugs has been established and the relevance of these parameters to crystallization of amorphous drugs is also assessed. Moreover, the crystallization kinetics of model drugs under isothermal conditions has been studied using Johnson-Mehl-Avrami (JMA) approach to determine the Avrami constant ‘n’ which provides an insight into the mechanism of crystallization. To further probe into the crystallization mechanism, the non-isothermal crystallization kinetics of model systems was also analysed by statistically fitting the crystallization data to 15 different kinetic models and the relevance of model-free kinetic approach has been established. In addition, the crystallization mechanism for DPM and CNZ at each extent of transformation has been predicted. The calculated fragility, glass forming ability (GFA) and crystallization kinetics is found to be in good correlation with the stability prediction of amorphous solid dispersions. Thus, this research work involves a multidisciplinary approach to establish fragility, GFA and crystallization kinetics as stability predictors for amorphous drug formulations.

Keywords: amorphous, fragility, glass forming ability, molecular mobility, mean relaxation time, crystallization kinetics, stability

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Authors: Michael Regev, Shai Essel, Alexander Katz-Demyanetz

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Magnesium alloys are characterized by good physical properties: They exhibit high strength, are lightweight and have good damping absorption and good thermal and electrical conductivity. Amorphous magnesium alloys, moreover, exhibit higher strength, hardness and a large elastic domain in addition to having excellent corrosion resistance. These above-mentioned advantages make magnesium based metallic glasses attractive for industrial use. Among the various existing magnesium alloys, Mg₆₅Cu₂₅Y₁₀ alloy is known to be one of the best glass formers. In the current study, Mg₆₅Cu₂₅Y₁₀ ribbons were produced by melt spinning, their microstructure was investigated in its as-cast condition, after pressing under 0.5 GPa for 5 minutes under different temperatures - RT, 500C, 1000C, 1500C and 2000C - and after five minute exposure to the above temperatures without pressing. The microstructure was characterized by means of X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), High Resolution Scanning Electron Microscope (HRSEM) and High Resolution Transmission Electron Microscopy (HRTEM). XRD and DSC studies showed that the as-cast material had an amorphous character and that the material crystallized during exposure to temperature with or without applying stress. HRTEM revealed that the as-cast Mg65Cu25Y10, although known to be one of the best glass formers, is nano-crystalline rather than amorphous. The current study casts light on the question what an amorphous alloy is and whether there is any clear borderline between amorphous and nano-crystalline alloys.

Keywords: metallic glass, magnesium, melt spinning, amorphous alloys

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Authors: Goodness Onwuka, Khaled Abou-El-Hossein

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Borosilicate-crown (BK7) glass has found broad application in the optic and automotive industries and the growing demands for nanometric surface finishes is becoming a necessity in such applications. Thus, it has become paramount to optimize the parameters influencing the surface roughness of this precision lens. The research was carried out on a 4-axes Nanoform 250 precision lathe machine with an ultra-high precision grinding spindle. The experiment varied the machining parameters of feed rate, wheel speed and depth of cut at three levels for different combinations using Box Behnken design of experiment and the resulting surface roughness values were measured using a Taylor Hobson Dimension XL optical profiler. Acoustic emission monitoring technique was applied at a high sampling rate to monitor the machining process while further signal processing and feature extraction methods were implemented to generate the input to a neural network algorithm. This paper highlights the training and development of a back propagation neural network prediction algorithm through careful selection of parameters and the result show a better classification accuracy when compared to a previously developed response surface model with very similar machining parameters. Hence artificial neural network algorithms provide better surface roughness prediction accuracy in the ultra-high precision grinding of BK7 glass.

Keywords: acoustic emission technique, artificial neural network, surface roughness, ultra-high precision grinding

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Authors: Nidhi Adhlakha, K. L. Yadav

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Three phase magnetoelectric (ME) composites (1-x)(0.7BiFeO3-0.3CoFe2O4)-xPbTiO3 (or equivalently written as (1-x)(0.7BFO-0.3CFO)-xPT) with x variations 0, 0.30, 0.35, 0.40, 0.45 and 1.0 were synthesized using hybrid processing route. The effects of PT addition on structural, multiferroic and optical properties have been subsequently investigated. A detailed Rietveld refinement analysis of X-ray diffraction patterns has been performed, which confirms the presence of structural phases of individual constituents in the composites. Field emission scanning electron microscopy (FESEM) images are taken for microstructural analysis and grain size determination. Transmission electron microscopy (TEM) analysis of 0.3CFO-0.7BFO reveals the average particle size to be lying in the window of 8-10 nm. The temperature dependent dielectric constant at various frequencies (1 kHz, 10 kHz, 50 kHz, 100 kHz and 500 kHz) has been studied and the dielectric study reveals that the increase of dielectric constant and decrease of average dielectric loss of composites with incorporation of PT content. The room temperature ferromagnetic behavior of composites is confirmed through the observation of Magnetization vs. Magnetic field (M-H) hysteresis loops. The variation of magnetization with temperature indicates the presence of spin glass behavior in composites. Magnetoelectric coupling is evidenced in the composites through the observation of the dependence of the dielectric constant on the magnetic field, and magnetodielectric response of 2.05 % is observed for 45 mol% addition of PT content. The fractional change of magnetic field induced dielectric constant can also be expressed as ∆ε_r~γM^2 and the value of γ is found to be ~1.08×10-2 (emu/g)-2 for composite with x=0.40. Fourier transformed infrared (FTIR) spectroscopy of samples is carried out to analyze various bonds formation in the composites.

Keywords: composite, X-ray diffraction, dielectric properties, optical properties

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Authors: Tran Ich Thinh, Nguyen Manh Cuong

Abstract:

Free vibrations of partial fluid-filled composite truncated conical shells are investigated using the Dynamic Stiffness Method (DSM) or Continuous Element Method (CEM) based on the First Order Shear Deformation Theory (FSDT) and non-viscous incompressible fluid equations. Numerical examples are given for analyzing natural frequencies and harmonic responses of clamped-free conical shells partially and completely filled with fluid. To compare with the theoretical results, detailed experimental results have been obtained on the free vibration of a clamped-free conical shells partially filled with water by using a multi-vibration measuring machine (DEWEBOOK-DASYLab 5.61.10). Three glass fiber/polyester composite truncated cones with the radius of the larger end 285 mm, thickness 2 mm, and the cone lengths along the generators are 285 mm, 427.5 mm and 570 mm with the semi-vertex angles 27, 14 and 9 degrees respectively were used, and the filling ratio of the contained water was 0, 0.25, 0.50, 0.75 and 1.0. The results calculated by proposed computational model for studied composite conical shells are in good agreement with experiments. Obtained results indicate that the fluid filling can reduce significantly the natural frequencies of composite conical shells. Parametric studies including circumferential wave number, fluid depth and cone angles are carried out.

Keywords: dynamic stiffness method, experimental study, free vibration, fluid-shell interaction, glass fiber/polyester composite conical shell

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Authors: C. Fornacelli, P. Colomban, E. Mugnaioli, I. Memmi Turbanti

Abstract:

When semiconductor particles are reduced in scale to nanometer dimension, their optical and electro-optical properties strongly differ from those of bulk crystals of the same composition. Since sampling is often not allowed concerning cultural heritage artefacts, the potentialities of two non-invasive techniques, such as Raman and Fiber Optic Reflectance Spectroscopy (FORS), have been investigated and the results of the analysis on some original glasses of different colours (from yellow to orange and deep red) and periods (from the second decade of the 20th century to present days) are reported in the present study. In order to evaluate the potentialities of the application of non-invasive techniques to the investigation of the structure and distribution of nanoparticles dispersed in a glass matrix, Scanning Electron Microscopy (SEM) and energy-disperse spectroscopy (EDS) mapping, together with Transmission Electron Microscopy (TEM) and Electron Diffraction Tomography (EDT) have also been used. Raman spectroscopy allows a fast and non-destructive measure of the quantum dots composition and size, thanks to the evaluation of the frequencies and the broadening/asymmetry of the LO phonons bands, respectively, though the important role of the compressive strain arising from the glass matrix and the possible diffusion of zinc from the matrix to the nanocrystals should be taken into account when considering the optical-phonons frequency values. The incorporation of Zn has been assumed by an upward shifting of the LO band related to the most abundant anion (S or Se), while the role of the surface phonons as well as the confinement-induced scattering by phonons with a non-zero wavevectors on the Raman peaks broadening has been verified. The optical band gap varies from 2.42 eV (pure CdS) to 1.70 eV (CdSe). For the compositional range between 0.5≤x≤0.2, the presence of two absorption edges has been related to the contribution of both pure CdS and the CdSxSe1-x solid solution; this particular feature is probably due to the presence of unaltered cubic zinc blende structures of CdS that is not taking part to the formation of the solid solution occurring only between hexagonal CdS and CdSe. Moreover, the band edge tailing originating from the disorder due to the formation of weak bonds and characterized by the Urbach edge energy has been studied and, together with the FWHM of the Raman signal, has been assumed as a good parameter to evaluate the degree of topological disorder. SEM-EDS mapping showed a peculiar distribution of the major constituents of the glass matrix (fluxes and stabilizers), especially concerning those samples where a layered structure has been assumed thanks to the spectroscopic study. Finally, TEM-EDS and EDT were used to get high-resolution information about nanocrystals (NCs) and heterogeneous glass layers. The presence of ZnO NCs (< 4 nm) dispersed in the matrix has been verified for most of the samples, while, for those samples where a disorder due to a more complex distribution of the size and/or composition of the NCs has been assumed, the TEM clearly verified most of the assumption made by the spectroscopic techniques.

Keywords: CdSxSe1-x, EDT, glass, spectroscopy, TEM-EDS

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Authors: Zakiullah Kalwar, Shabeer Ahmed Abbasi

Abstract:

This research encompasses the study of Cretaceous Sembar Formation Shale Gas potential at Hajipur area. This study has been done with the approach of geophysical data integration. The structure is NE – SW trending anticline with two map able compartments at Cretaceous Sembar level. The study area is located within proven petroleum system. Cretaceous Sembar/Goru formation is in a Wet gas window and Tertiary source is possibly in the oil window. Potential seals are present in Upper Ranikot shale beds and Intra-Lower Ranikot shales. The effectiveness and presence of source and reservoir rocks are favorable in the area of interest. Cretaceous Sembar Shale and Goru Shale beds with good organic content (TOC upto 4%, Type II/III) are currently in gas generation window in the area. Source rock intervals are also reported in Eocene Kirthar Group (TOC upto 8%, Type –II). Good reservoir quality Paleocene Lower Ranikot and Cretaceous Sembar shale beds exist in the area. The collision between Indian and Eurasian Plates during Tertiary initiated folding and thrusting. The first phase of thrusting involved ophiolite emplacement along the western margins of the Indian Plate (west of the area under review). The main phase of thrusting in the Sulaiman region was from Late Miocene to the present. The study area contains Permian to Recent clastics and carbonates. The succession generally is younger in the southeast than in northwest. Intraformational sedimentation breaks are pronounced in Permian and Jurassic. Sulaiman Range is bounded by the Western Sulaiman Transform Fault Zone (of which the Kingri Fault is the major fault) to the west and by the Domanda Fault to the east. The Domanda Fault also constitutes the western boundary of the Sulaiman Foredeep, lies in sulaiman foredeep where subsurface having prominent independent closure. Several reservoir horizons of Jurassic to Eocene are established hydrocarbon producers in the Hajipur area.

Keywords: enough size, good potential, shale gas, structure closure

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Authors: Ranojoy Dutta, Adam Barker

Abstract:

Multifamily residential buildings are increasingly being built with large glazed areas to provide tenants with greater daylight and outdoor views. However, traditional double-glazed window assemblies can lead to significant thermal discomfort from high radiant temperatures as well as increased cooling energy use to address solar gains. Dynamic glazing provides an effective solution by actively controlling solar transmission to maintain indoor thermal comfort, without compromising the visual connection to outdoors. This study uses thermal simulations across three Canadian cities (Toronto, Vancouver and Montreal) to verify if dynamic glazing along with operable windows and ceiling fans can maintain the indoor operative temperature of a prototype southwest facing high-rise apartment unit within the ASHRAE 55 adaptive comfort range for a majority of the year, without any mechanical cooling. Since this study proposes the use of natural ventilation for cooling and the typical building life cycle is 30-40 years, the typical weather files have been modified based on accepted global warming projections for increased air temperatures by 2050. Results for the prototype apartment confirm that thermal discomfort with dynamic glazing occurs only for less than 0.7% of the year. However, in the baseline scenario with low-E glass there are up to 7% annual hours of discomfort despite natural ventilation with operable windows and improved air movement with ceiling fans.

Keywords: electrochromic glazing, multi-family housing, passive cooling, thermal comfort, natural ventilation

Procedia PDF Downloads 75

Authors: A. Mourtzikou, D. Sygkridou, T. Georgakopoulos, G. Katsagounos, E. Stathatos

Abstract:

Over 60% highly transparent quasi-solid-state dye-sensitized solar cells (DSSCs) with dimension of 50x50 cm² were fabricated via inkjet printing process using nanocomposite inks as raw materials and tested under outdoor illumination conditions. The cells were electrically characterized, and their possible application to the shell of greenhouses was also examined. The panel design was in Z-interconnection, where the working electrode was inkjet printed on one conductive glass and the counter electrode on a second glass in a sandwich configuration. Silver current collective fingers were printed on the glasses to make the internal electrical connections. In that case, the adjacent cells were connected in series via silver fingers and finally insulated using a UV curing resin to protect them from the corrosive (I^-/I₃^-) redox couple of the electrolyte.

Keywords: Dye-sensitized solar panels, inkjet printing, quasi-solid state electrolyte, semi-transparency, scale up

Procedia PDF Downloads 108

Authors: Tahsin Shameem, Chowdhury Sadman Jahan, Mohammad Alam

Abstract:

Interest about Net Zero Energy Buildings have gained traction in recent years following the need to sustain energy consumption with generations on site and to reduce dependence on grid supplied energy from large plants using fossil fuel. With this end in view, building integrated photovoltaics are being studied attempting to utilize all exterior facades of a building to generate power. In this paper, we have looked at the physical parameters defining a dye sensitized solar cell (DSSC) and discussed their impact on energy harvest. Following our discussion and experimental data obtained from literature, we have attempted to optimize these physical parameters accordingly so as to allow maximum light absorption for a given active layer thickness. We then modified a planer DSSC design with our optimized properties to allow adequate light transmission which demonstrated a high fill factor and an External Quantum Efficiency (EQE) of greater than 9% by computer aided design and simulation. In conclusion, a DSSC based solar window with such high output values even after such high light transmission through it definitely flags a promising future for this technology and our work elicits the need for further study and practical experimentation.

Keywords: net zero energy building, integrated photovoltaics, dye sensitized solar cell, fill factor, External Quantum Efficiency

Procedia PDF Downloads 109