Search results for: pneumatic actuator fabrication

Authors: Temesgen Geremew

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This study investigates the evolution of polythiophene nanoparticles (PThNPs) as surface-enhanced Raman spectroscopy (SERS) sensors for Pb²⁺ detection in river water. We analyze the PThNPs' optical, structural, and morphological properties at different stages of their development to understand their SERS performance. Techniques like UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) are employed for characterization. The SERS sensitivity towards Pb²⁺ is evaluated by monitoring the peak intensity of a specific Raman band upon increasing metal ion concentration. The study aims to elucidate the relationship between the PThNPs' characteristics and their SERS efficiency for Pb²⁺ detection, paving the way for optimizing their design and fabrication for improved sensing performance in real-world environmental monitoring applications.

Keywords: polythiophene, Pb2+, SERS, nanoparticles

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Authors: Khursheed Ahmad, Shaikh M. Mobin

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In this work, we have developed a highly stable planar heterojunction perovskite solar cells (PSCs) with a architecture (ITO/GO/PEDOT:PSS/MAPbI3/PCBM/Carbon tape). The PSCs was fabricated under air using GO/PEDOT:PSS as hole transport layer while the carbon tape used as a back contact to complete the device. The fabricated PSCs device exhibited good stability and performance in terms of power conversion efficiency of 5.2%. The PSCs devices were exposed to ambient condition for 4 days which shows excellent stability confirmed by XRD analysis. We believed that the stability of the planar heterojunction perovskite solar cell may be due the presence of GO which inhibits the direct contact between PEDOT:PSS and MAPbI3.

Keywords: graphene oxide, perovskite solar cells, hole transport layer, PEDOT:PSS

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Authors: Yana Posmitnaya, Galina Rudnitskaya, Tatyana Lukashenko, Anton Bukatin, Anatoly Evstrapov

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An important area of biological and medical research is the study of genetic mutations and polymorphisms that can alter gene function and cause inherited diseases and other diseases. The following methods to analyse DNA fragments are used: capillary electrophoresis and electrophoresis on microfluidic chip (MFC), mass spectrometry with electrophoresis on MFC, hybridization assay on microarray. Electrophoresis on MFC allows to analyse small volumes of samples with high speed and throughput. A soft lithography in polydimethylsiloxane (PDMS) was chosen for operative fabrication of MFCs. A master-form from silicon and photoresist SU-8 2025 (MicroChem Corp.) was created for the formation of micro-sized structures in PDMS. A universal topology which combines T-injector and simple cross was selected for the electrophoretic separation of the sample. Glass K8 and PDMS Sylgard® 184 (Dow Corning Corp.) were used for fabrication of MFCs. Electroosmotic flow (EOF) plays an important role in the electrophoretic separation of the sample. Therefore, the estimate of the quantity of EOF and the ways of its regulation are of interest for the development of the new methods of the electrophoretic separation of biomolecules. The following methods of surface modification were chosen to change EOF: high-frequency (13.56 MHz) plasma treatment in oxygen and argon at low pressure (1 mbar); 1% aqueous solution of polyvinyl alcohol; 3% aqueous solution of Kolliphor® P 188 (Sigma-Aldrich Corp.). The electroosmotic mobility was evaluated by the method of Huang X. et al., wherein the borate buffer was used. The influence of physical and chemical methods of treatment on the wetting properties of the PDMS surface was controlled by the sessile drop method. The most effective way of surface modification of MFCs, from the standpoint of obtaining the smallest value of the contact angle and the smallest value of the EOF, was the processing with aqueous solution of Kolliphor® P 188. This method of modification has been selected for the treatment of channels of MFCs, which are used for the separation of mixture of oligonucleotides fluorescently labeled with the length of chain with 10, 20, 30, 40 and 50 nucleotides. Electrophoresis was performed on the device MFAS-01 (IAI RAS, Russia) at the separation voltage of 1500 V. 6% solution of polydimethylacrylamide with the addition of 7M carbamide was used as the separation medium. The separation time of components of the mixture was determined from electropherograms. The time for untreated MFC was ~275 s, and for the ones treated with solution of Kolliphor® P 188 – ~ 220 s. Research of physical-chemical methods of surface modification of MFCs allowed to choose the most effective way for reducing EOF – the modification with aqueous solution of Kolliphor® P 188. In this case, the separation time of the mixture of oligonucleotides decreased about 20%. The further optimization of method of modification of channels of MFCs will allow decreasing the separation time of sample and increasing the throughput of analysis.

Keywords: electrophoresis, microfluidic chip, modification, nucleic acid, polydimethylsiloxane, soft lithography

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Authors: Vipin Saini, Sunil Kamboj, Suman Bala, A. Pandurangan

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The present research is aimed at fabrication of multiple-unit controlled-release tablet formulation of aceclofenac by employing acrylic polymers as the release controlling excipients for drug multi-particulates to achieve the desired objectives of maintaining the same controlled release characteristics as that prior to their compression into tablet. Various manufacturers are successfully manufacturing and marketing aceclofenac controlled release tablet by applying directly coating materials on the tablet. The basic idea behind development of such formulations was to employ aqueous acrylics polymers dispersion as an alternative to the existing approaches, wherein the forces of compression may cause twist of drug pellets, but do not have adverse effects on the drug release properties. Thus, the study was undertaken to illustrate manufacturing of controlled release aceclofenac multiple-unit tablet formulation.

Keywords: aceclofenac, multiple-unit tablets, acrylic polymers, controlled-release

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Authors: Syed Sadique Anwer Askari, Mukul Kumar Das

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Zinc Oxide (ZnO) solar cells have drawn great attention due to the enhanced efficiency and low-cost fabrication process. In this study, ZnO thin film is used as the active layer, hole blocking layer, antireflection coating (ARC) as well as transparent conductive oxide. To improve the conductivity of ZnO, top layer of ZnO is doped with aluminum, for top contact. Intrinsic carrier concentration of silicon substrate plays an important role in enhancing the power conversion efficiency (PCE) of ZnO/Si solar cell. With the increase of intrinsic carrier concentration PCE decreased due to increase in dark current in solar cell. At 80nm ZnO and 160µm Silicon substrate thickness, power conversion efficiency of 26.45% and 21.64% is achieved with intrinsic carrier concentration of 1x109/cm3, 1.4x1010/cm3 respectively.

Keywords: hetero-junction solar cell, solar cell, substrate intrinsic carrier concentration, ZnO/Si

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Authors: Paulo Mendonca, Nzar Faiq Naqeshbandi

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The objective of this study is to propose an interactive design environment that outlines the underlying computational framework to reach self-supporting overhangs. The research demonstrates the digital printability of overhangs taking into consideration factors related to the geometry design, the material used, the applied support, and the printing set-up of slicing and the extruder inclination. Parametric design tools can contribute to the design phase, form-finding, and stability optimization of self-supporting structures while printing in order to hold the components in place until they are sufficiently advanced to support themselves. The challenge is to ensure the stability of the printed parts in the critical inclinations during the whole fabrication process. Facilitating the identification of parameterization will allow to predict and optimize the process. Later, in the light of the previous findings, some guidelines of simulations and physical tests are given to be conducted for estimating the structural and functional performance.

Keywords: additive manufacturing, overhangs, self-support overhangs, printability, parametric tools

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Authors: Yakup Ulusu, Faruk Ozel, Numan Eczacioglu, Abdurrahman Ozen, Sabriye Acikgoz

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GFP discovered in the mid-1970s, has been used as a marker after replicated genetic study by scientists. In biotechnology, cell, molecular biology, the GFP gene is frequently used as a reporter of expression. In modified forms, it has been used to make biosensors. Many animals have been created that express GFP as an evidence that a gene can be expressed throughout a given organism. Proteins labeled with GFP identified locations are determined. And so, cell connections can be monitored, gene expression can be reported, protein-protein interactions can be observed and signals that create events can be detected. Additionally, monitoring GFP is noninvasive; it can be detected by under UV-light because of simply generating fluorescence. Moreover, GFP is a relatively small and inert molecule, that does not seem to treat any biological processes of interest. The synthesis of GFP has some steps like, to construct the plasmid system, transformation in E. coli, production and purification of protein. GFP carrying plasmid vector pBAD–GFPuv was digested using two different restriction endonuclease enzymes (NheI and Eco RI) and DNA fragment of GFP was gel purified before cloning. The GFP-encoding DNA fragment was ligated into pET28a plasmid using NheI and Eco RI restriction sites. The final plasmid was named pETGFP and DNA sequencing of this plasmid indicated that the hexa histidine-tagged GFP was correctly inserted. Histidine-tagged GFP was expressed in an Escherichia coli BL21 DE3 (pLysE) strain. The strain was transformed with pETGFP plasmid and grown on LuiraBertoni (LB) plates with kanamycin and chloramphenicol selection. E. coli cells were grown up to an optical density (OD 600) of 0.8 and induced by the addition of a final concentration of 1mM isopropyl-thiogalactopyranoside (IPTG) and then grown for additional 4 h. The amino-terminal hexa-histidine-tag facilitated purification of the GFP by using a His Bind affinity chromatography resin (Novagen). Purity of GFP protein was analyzed by a 12 % sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The concentration of protein was determined by UV absorption at 280 nm (Varian Cary 50 Scan UV/VIS spectrophotometer). Synthesis of GFP-Polymer composite nanofibers was produced by using GFP solution (10mg/mL) and polymer precursor Polyvinylpyrrolidone, (PVP, Mw=1300000) as starting materials and template, respectively. For the fabrication of nanofibers with the different fiber diameter; a sol–gel solution comprising of 0.40, 0.60 and 0.80 g PVP (depending upon the desired fiber diameter) and 100 mg GFP in 10 mL water: ethanol (3:2) mixtures were prepared and then the solution was covered on collecting plate via electro spinning at 10 kV with a feed-rate of 0.25 mL h-1 using Spellman electro spinning system. Results show that GFP-based nano-fiber can be used plenty of biomedical applications such as bio-imaging, bio-mechanic, bio-material and tissue engineering.

Keywords: biomaterial, GFP, nano-fibers, protein expression

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Authors: C. Tezara, H. Y. Lim, M. H. Yazdi, J. W. Lim, J. P. Siregar

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Natural fibre has become an element in human lives. A lot of researchers have conducted research about natural fibre reinforced polymer. Malaysian government has spent a lot of money on the research funding for researchers and academician especially research on kenaf fibre due to exclusion of tobacco from AFTA (Asean Free Trade Area) list. This work is to investigate the mechanical properties of kenaf fiber reinforced epoxy composite where short kenaf fibre was applied and the mechanical properties of 5%, 10% and 15% wt. of kenaf fibre were added into the mixture of epoxy resin. Hand lay-up process was selected in the fabrication of the specimen for testing. The tensile, flexural and impact test were conducted following ASTM D3039, ASTM D790 and ASTM D256 accordingly. From the experiment result, the effect of different fiber loading of the specimen on its mechanical properties would be analyzed and compared in the result and discussion.

Keywords: Kenaf fibre, epoxy, composite, fibre

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Authors: Atasi Dan, Kamanio Chattopadhyay, Bikramjit Basu

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A cost-effective titanium diboride (TiB2) paint coating has been developed on stainless steel substrate using commercially available polyvinylpyrrolidone as a binder by convenient dip-coating technique. The emittance of the coating has been explored by tailoring various process parameters to obtain highest thermal radiation. The optimized coating has achieved a high thermal emittance of 0.85. In addition, the coating exhibited an excellent thermal stability while heat-treated at 500 °C in air. Along with the emittance, the structural and physical properties of the As-deposited and heat-treated coatings have been investigated systematically. The high temperature annealing has not affected the emittance, chemical composition and morphology of the coating significantly. Hence, the fabricated paint coating is expected to open up new possibilities for using it as a low-cost, thermally stable emitter in high temperature applications.

Keywords: titanium diboride, emittance, paint coating, thermal stability

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Authors: Mitali Saha, Soma Das

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The fabrication of nanoscale materials for use in chemical sensing, biosensing and biological analyses has proven a promising avenue in the last few years. Cholesterol has aroused considerable interest in recent years on account of its being an important parameter in clinical diagnosis. There is a strong positive correlation between high serum cholesterol level and arteriosclerosis, hypertension, and myocardial infarction. Enzyme-based electrochemical biosensors have shown high selectivity and excellent sensitivity, but the enzyme is easily denatured during its immobilization procedure and its activity is also affected by temperature, pH, and toxic chemicals. Besides, the reproducibility of enzyme-based sensors is not very good which further restrict the application of cholesterol biosensor. It has been demonstrated that carbon nanotubes could promote electron transfer with various redox active proteins, ranging from cytochrome c to glucose oxidase with a deeply embedded redox center. In continuation of our earlier work on the synthesis and applications of carbon and metal based nanoparticles, we have reported here the synthesis of carbon nanotubes (CCNT) by burning coconut oil under insufficient flow of air using an oil lamp. The soot was collected from the top portion of the flame, where the temperature was around 6500C which was purified, functionalized and then characterized by SEM, p-XRD and Raman spectroscopy. The SEM micrographs showed the formation of tubular structure of CCNT having diameter below 100 nm. The XRD pattern indicated the presence of two predominant peaks at 25.20 and 43.80, which corresponded to (002) and (100) planes of CCNT respectively. The Raman spectrum (514 nm excitation) showed the presence of 1600 cm-1 (G-band) related to the vibration of sp2-bonded carbon and at 1350 cm-1 (D-band) responsible for the vibrations of sp3-bonded carbon. A nonenzymatic cholesterol biosensor was then fabricated on an insulating Teflon material containing three silver wires at the surface, covered by CCNT, obtained from coconut oil. Here, CCNTs worked as working as well as counter electrodes whereas reference electrode and electric contacts were made of silver. The dimensions of the electrode was 3.5 cm×1.0 cm×0.5 cm (length× width × height) and it is ideal for working with 50 µL volume like the standard screen printed electrodes. The voltammetric behavior of cholesterol at CCNT electrode was investigated by cyclic voltammeter and differential pulse voltammeter using 0.001 M H2SO4 as electrolyte. The influence of the experimental parameters on the peak currents of cholesterol like pH, accumulation time, and scan rates were optimized. Under optimum conditions, the peak current was found to be linear in the cholesterol concentration range from 1 µM to 50 µM with a sensitivity of ~15.31 μAμM−1cm−2 with lower detection limit of 0.017 µM and response time of about 6s. The long-term storage stability of the sensor was tested for 30 days and the current response was found to be ~85% of its initial response after 30 days.

Keywords: coconut oil, CCNT, cholesterol, biosensor

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Authors: Meichen Lee, Michael K. H. Leung

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In recent years, visible-light activated photocatalysis has become a major field of intense researches for the higher efficiency of solar energy utilizations. Many attempts have been made on the modification of wide band gap semiconductors, while more and more efforts emphasize on cost-effective synthesis of visible-light activated catalysts. In this work, BiOBr nanoplates with band gap of visible-light range are synthesized through a promising microwave solvothermal method. The treatment time period and temperature dependent BiOBr nanosheets of various particle sizes are investigated through SEM. BiOBr synthesized under the condition of 160°C for 60 mins shows the most uniform particle sizes around 311 nm and the highest surface-to-volume ratio on account of its smallest average particle sizes compared with others. It exhibits the best photocatalytic behavior among all samples in RhB degradation.

Keywords: microwave solvothermal process, nanoplates, solar energy, visible-light photocatalysis

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Authors: Reza Hadjiaghaie Vafaie, Sevda Givtaj

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Automation and control of biological samples and solutions at the microscale is a major advantage for biochemistry analysis and biological diagnostics. Despite the known potential of miniaturization in biochemistry and biomedical applications, comparatively little is known about fluid automation and control at the microscale. Here, we study the electric field effect inside a fluidic channel and proper electrode structures with different patterns proposed to form forward, reversal, and rotational flows inside the channel. The simulation results confirmed that the ac electro-thermal flow is efficient for the control and automation of high-conductive solutions. In this research, the fluid pumping and mixing effects were numerically studied by solving physic-coupled electric, temperature, hydrodynamic, and concentration fields inside a microchannel. From an experimental point of view, the electrode structures are deposited on a silicon substrate and bonded to a PDMS microchannel to form a microfluidic chip. The motions of fluorescent particles in pumping and mixing modes were captured by using a CCD camera. By measuring the frequency response of the fluid and exciting the electrodes with the proper voltage, the fluid motions (including pumping and mixing effects) are observed inside the channel through the CCD camera. Based on the results, there is good agreement between the experimental and simulation studies.

Keywords: microfluidic, nano/micro actuator, AC electrothermal, Reynolds number, micropump, micromixer, microfabrication, mass transfer, biomedical applications

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Authors: Yu Chen, Seong-Jin Kim, Jaehoon Chung

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High throughput cells counting and sizing are often required for biomedical applications. Here we report design, fabrication and validating of a micro-machined Coulter counter device with multiple-channel to realize such application for low cost. Multiple vertical through-holes were fabricated on a silicon chip, combined with the PDMS micro-fluidics channel that serves as the sensing channel. In order to avoid the crosstalk introduced by the electrical connection, instead of measuring the current passing through, the potential of each channel is monitored, thus the high throughput is possible. A peak of the output potential can be captured when the cell/particle is passing through the microhole. The device was validated by counting and sizing the polystyrene beads with diameter of 6 μm, 10 μm and 15 μm. With the sampling frequency to be set at 100 kHz, up to 5000 counts/sec for each channel can be realized. The counting and enumeration of MCF7 cancer cells are also demonstrated.

Keywords: Coulter counter, cell enumeration, high through-put, cell sizing

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Authors: Kooshina Koosha, Sima Habibi, Azam Talebian

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Electrospinning is a simple, versatile and widely accepted technique to produce ultra-fine fibers ranging from nanometer to micron. Recently there has been great interest in developing this technique to produce nanofibers with novel properties and functionalities. The electrospinning field is extremely broad, and consequently there have been many useful reviews discussing various aspects from detailed fiber formation mechanism to the formation of nanofibers and to discussion on a wide range of applications. On the other hand, the focus of this study is quite narrow, highlighting electrospinning parameters. This work will briefly cover the solution and processing parameters (for instance; concentration, solvent type, voltage, flow rate, distance between the collector and the tip of the needle) impacting the morphological characteristics of nanofibers, such as diameter. In this paper, a comprehensive work would be presented on the research of producing nanofibers from natural polymer entitled Gelatin.

Keywords: electrospinning, solution parameters, process parameters, natural fiber

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Authors: Sahari Japar, Rodney Jammy, M. A. Maleque

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The fabrication of melaleuca alternifolia fibre reinforced thermoplastic starch composites was successfully done. This paper aims to show the effect of melaleuca alternifolia fibres on mechanical and physical properties of composites by using starch as a matrix. The fibres were extracted from three different part i.e. tea tree trunk (TTT), tea tree bunch (TTB) and tea tree leaf (TTL) and combined with tapioca starch by casting method. All composites showed superior mechanical properties in comparison to TS. The addition of 5% (v/v) fibres as a filler to TS led to the improvement in young’s modulus by 350% for TTB/TS, 282% for TTT/TS and 220% for TTL/TS. The tensile strength also increased to 34.39% for TTL/TS, 82.80% for TTB/TS and 203.18% for TTT/TS respectively. The trend can be correlated to the amount of cellulose in the fibres. For physical properties, it can be seen that, with the addition of fibres, the water absorption and swelling of composites decreased. The addition of melaleuca alternifolia fibre improved mechanical and physical properties of thermoplastic starch composites.

Keywords: melaleuca alternifolia, fibre, starch, mechanical, physical

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Authors: Mohini M. Sain, Vijay Kumar, Tasmia Tabassem, Jimi Tjong

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In the recent times, the Lithium-sulfur batteries (LiSBs) have emerged as a highly promising next generation of secondary batteries for their high theoretical specific capacity (1675 mAh/g) and low cost, and they have shown immense possibilities in utilizing in battery operated electric vehicles (BEVs). However, the commercialization of LiSBs is restricted due to the slow redox kinetics of sulfur cathode and shuttling effect of polysulfides during battery operation. Thus, the development of novel host materials is crucial for suppressing the dissolution of polysulfides into electrolyte, and this eventually helps in resolving the long-term cycling problem in LiSBs. This work provides a simple and straightforward method to design carbon materials with optimized nitrogen content with high surface area and thus simultaneously reveals new methods and strategies for realizing high performance host material design for practical LiSBs.

Keywords: Li ion battery, graphtitic carbon, electrode fabrication, BeV

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Authors: Ghazi Faisal Najmuldeen, Wahida Amat Fadzila

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The aim of this study is to investigate physical and mechanical properties of experimental particleboards manufactured from mixing the oil palm fronds particles with empty fruit bunch fibers. Variables were two blending ratios (100:0 and 70:30), press temperature (160°C and 180°C) and press time (180 and 300 s). Experimental boards with a target density of 750 kg m-3 were manufactured from these two particles and fibers blended with urea formaldehyde resin and compressed into targeted thickness. The effect of these manufacturing conditions on bending strength, internal bonding, water absorption and thickness swelling were determined. From this research, it can be concluded that hybridization of fibers with fronds particles improved some properties of particleboard. Empty fruit bunch fibers and fronds particleboard showed better modulus of rupture and internal bonding than fronds particleboards.

Keywords: oil palm fronds, empty fruit bunch, particleboards, chemistry, environment

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Authors: D. Ponnamma, E. Alper, P. Sharma, M. A. AlMaadeed

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Integrating efficient energy harvesting materials into soft, flexible and eco-friendly substrates could yield significant breakthroughs in wearable and flexible electronics. Here we present a tri phasic filler combination of one-dimensional titanium dioxide nanotubes, two-dimensional reduced graphene oxide, and three-dimensional strontium titanate, introduced into a semi crystalline polymer, Poly(vinylidene fluoride-co-hexafluoropropylene). Simple mixing method is adopted for the composite fabrication after ensuring a high interaction among the various fillers. The films prepared were mainly tested for the piezoelectric responses and the mechanical stretchability. The results show that the piezoelectric constant has increased while changing the total filler concentration. We propose an integration of these materials in fabricating energy conversion devices useful in flexible and wearable electronics.

Keywords: dielectric property, hydrothermal growth, piezoelectricity, polymer nanocomposites

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Authors: R. F. Louh, Cathy Chou, Victor Wang, Howard Yan

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The aim of this study is to manufacture titania and reduced graphene oxide (TiO2/rGO) composite nanofibers via electrospinning (ESP) of precursor fluid consisted of titania sol containing polyvinylpyrrolidone (PVP) and titanium isopropoxide (TTIP) and GO solution. The GO nanoparticles were derived from Hummers’ method. A metal grid ring was used to provide the bias voltage to reach higher ESP yield and nonwoven fabric with dense network of TiO2/GO composite nanofibers. The ESP product was heat treated at 500°C for 2 h in nitrogen atmosphere to acquire TiO2/rGO nanofibers by thermal reduction of GO and phase transformation into anatase TiO2. The TiO2/rGO nanofibers made from various volume fractions of GO solution by ESP were analyzed by FE-SEM, TEM, XRD, EDS, BET and FTIR. Such TiO2/rGO fibers having photocatalytic property, high specific surface area and electrical conductivity can be used for photovoltaics and chemical sensing applications.

Keywords: electrospinning process, titanium oxide, thermally reduced graphene oxide, composite nanofibers

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Authors: Viranshu Kumar, Hitesh Arora, Pradeep Joshi

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SS 304 is Austenitic stainless steel with Chromium and Nickel as basic constituents. It has excellent corrosion resistance properties and very good weldability. Austenitic stainless steels have superior mechanical properties at high temperatures and are used extensively in a range of applications. SS 304L has wide applications in various industries viz. Nuclear, Pharmaceutical, marine, chemical etc. due to its excellent applications and ease of joining this material has become very popular for fabrication as well as weld surfacing. Austenitic stainless steels have a tendency to form chromium depleted zones at the grain boundaries during welding and heat treatment, where chromium combines with available carbon in the vicinity of the grain boundaries, to produce an area depleted in chromium, and thus becomes susceptible to intergranular corrosion. This phenomenon is known as sensitization.

Keywords: sensitization, SS 304, GTAW, mechanical properties, carbideprecipitationHAZ, microstructure, micro hardness, tensile strength

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Authors: Daniel Nelson, Valeria La Saponara

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Material extrusion is an additive manufacturing modality that continues to show great promise in the ability to create low-cost, highly intricate, and exceedingly useful structural elements. As more capable and versatile filament materials are devised, and the resolution of manufacturing systems continues to increase, the need to understand and predict manufacturing-induced warping will gain ever greater importance. The following study presents an in situ remote sensing and data analysis construct that allows for the in situ mapping and quantification of surface displacements induced by residual stresses on a specified test structure. This proof-of-concept experimental process shows that it is possible to provide designers and manufacturers with insight into the manufacturing parameters that lead to the manifestation of these deformations and a greater understanding of the behavior of these warping events over the course of the manufacturing process.

Keywords: additive manufacturing, deformation, digital image correlation, fused filament fabrication, residual stress, warping

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Authors: Goban Kumar Panneer Selvam

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In past years, there is lots of death caused due to harmful gases. So its very important to monitor harmful gases for human safety, and semiconductor material play important role in producing effective gas sensors.A novel solvothermal synthesis method based on sol-gel processing was prepared to deposit tin oxide thin films on glass substrate at high temperature for gas sensing application. The structure and morphology of tin oxide were analyzed by X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The SEM analysis of how spheres shape in tin oxide nanoparticles. The structure characterization of tin oxide studied by X-ray diffraction shows 8.95 nm (calculated by sheers equation). The UV visible spectroscopy indicated a maximum absorption band shown at 390 nm. Further dope tin oxide with selected metals to attain maximum sensitivity using dip coating technique with different immersion and sensing characterization are measured.

Keywords: tin oxide, gas sensor, chlorine free, sensitivity, crystalline size

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Authors: S. S. Abdullahi, H. Musa, A. A. Salisu, A. Ismaila, A. H. Birniwa

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In this study the treated and untreated kenaf fiber reinforced unsaturated polyester conventional composites were prepared. Hand lay-up technique was used with dump-bell shaped mold. The kenaf bast fiber was retted enzymatically, washed, dried and combed with a nylon brush. A portion of the kenaf fiber was mercerized and treated with benzoylchloride prior to composite fabrication. Untreated kenaf fiber was also used to prepare the composites to serve as control. The cured composites were subjected to various mechanical testes, such as hardness test, impact test and tensile strength test. The results obtained indicated an increase in all the parameters tested with the fiber treatment. This is because the lignin, hemi-celluloses, pectin and other impurities were removed during alkaline treatment (i.e mercerization). This shows that, the durability of the natural cellulosic fibers to different composite applications can be achieved via fiber treatments.

Keywords: composite, kenaf fibre, reinforce, retted

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Authors: Liyew Yizengaw Yitayih

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This nanotechnology study focuses on how potassium ions (K+) affect lithium-ion (Li-ion) battery performance. By adding potassium ions (K+) to the lithium tin oxide (LiSnO) anode and employing styrene-butadiene rubber (SBR) as a binder, the doping of K+ was specifically studied. The methods employed in this study include computer modeling and simulation, material fabrication, and electrochemical characterization. The potassium ions (Li+) were successfully doped into the LiSnO lattice during charge/discharge cycles, which increased the lithium-ion diffusivity and electrical conductivity within the anode. However, it was found that internal doping of potassium ions (K+) into the LiSnO lattice occurred at high potassium ion concentrations (>16.6%), which hampered lithium ion transfer because of repulsion and physical blockage. The electrochemical efficiency of lithium-ion batteries was improved by this comprehensive study's presentation of potassium ions' (K+) potential advantages when present in the appropriate concentrations in electrode materials.

Keywords: lithium-ion battery, LiSnO anode, potassium doping, lithium-ion diffusivity, electronic conductivity

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Authors: Gurmeet Singh Cheema, Navjotinder Singh, Gurjinder Singh, Amardeep Singh

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Aluminium and its alloys play have excellent corrosion resistant properties, ease of fabrication and high specific strength to weight ratio. In this investigation an attempt has been made to study the effect of different post weld heat treatment methods on the mechanical and metallurgical properties of TIG welded joints of the commercial aluminium alloy. Three different methods of post weld heat treatments are, solution heat treatment, artificial aged and combination of solution heat treatment and artificial aging are given to TIG welded aluminium joints. Mechanical and metallurgical properties of as welded and post weld treated joints of the aluminium alloys was examined.

Keywords: aluminium alloys, TIG welding, post weld heat treatment

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Authors: A. Khosrozadeh, M. A. Darabi, M. Xing, Q. Wang

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Fabrication of a high-performance supercapacitor (SC) using a flexible cellulose-based composite film of polyaniline (PANI), reduced graphene oxide (RGO), and silver nanowires (AgNWs) is reported. The flexibility, high capacitive behaviour, and cyclic stability of the entire device make it a good candidate for wearable SCs. The results show that a capacitance as high as 73.4 F/g (1.6 F/cm2) at a discharge rate of 1.1 A/g is achieved by the device. In addition, the SC demonstrates a power density up to 468.8 W/kg and an energy density up to 5.1 wh/kg. The flexibility of the composite film is attributed to the binding effect of cellulose fibers as well as reinforcing effect of AgNWs. The excellent electrochemical performance of the device is found to be owing to the synergistic effect between PANI/RGO/AgNWs ternary in a cushiony cellulose matrix and porous structure of the composite.

Keywords: cellulose, polyaniline, reduced graphene oxide, silver, super capacitor

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Authors: M. Grandcolas, N. Rival, H. Bu, S. Jahren, R. Schmid, H. Johnsen

Abstract:

The concept of an autonomic self-healing material, where initiation of repair is integrated to the material, is now being considered for engineering applications and is a hot topic in the literature. Among several concepts/techniques, two are most interesting: i) Capsules: Integration of microcapsules in or at the surface of coatings or fibre-like structures has recently gained much attention. Upon damage-induced cracking, the microcapsules are broken by the propagating crack fronts resulting in a release of an active chemical (healing agent) by capillary action, subsequently repairing and avoiding further crack growth. ii) Self-healing polymers: Interestingly, the introduction of dynamic covalent bonds into polymer networks has also recently been used as a powerful approach towards the design of various intrinsically self-healing polymer systems. The idea behind this is to reconnect the chemical crosslinks which are broken when a material fractures, restoring the integrity of the material and thereby prolonging its lifetime. We propose here to integrate both self-healing concepts (capsules, self-healing polymers) in electrospun fibres and coatings. Different capsule preparation approaches have been investigated in SINTEF. The most advanced method to produce capsules is based on emulsification to create a water-in-oil emulsion before polymerisation. The healing agent is a polyurethane-based dispersion that was encapsulated in shell materials consisting of urea-benzaldehyde resins. Results showed the successful preparation of microcapsules and release of the agent when capsules break. Since capsules are produced in water-in-oil systems we mainly investigated organic solvent based coatings while a major challenge resides in the incorporation of capsules into water-based coatings. We also focused on developing more robust microcapsules to prevent premature rupture of the capsules. The capsules have been characterized in terms of size, and encapsulation and release might be visualized by incorporating fluorescent dyes and examine the capsules by microscopy techniques. Alternatively, electrospinning is an innovative technique that has attracted enormous attention due to unique properties of the produced nano-to-micro fibers, ease of fabrication and functionalization, and versatility in controlling parameters. Especially roll-to-roll electrospinning is a unique method which has been used in industry to produce nanofibers continuously. Electrospun nanofibers can usually reach a diameter down to 100 nm, depending on the polymer used, which is of interest for the concept with self-healing polymer systems. In this work, we proved the feasibility of fabrication of POSS-based (POSS: polyhedral oligomeric silsesquioxanes, tradename FunzioNano™) nanofibers via electrospinning. Two different formulations based on aqueous or organic solvents have shown nanofibres with a diameter between 200 – 450nm with low defects. The addition of FunzioNano™ in the polymer blend also showed enhanced properties in term of wettability, promising for e.g. membrane technology. The self-healing polymer systems developed are here POSS-based materials synthesized to develop dynamic soft brushes.

Keywords: capsules, coatings, electrospinning, fibers

Procedia PDF Downloads 262

Authors: Liangliang Tang, Chang Xu, Xingying Chen

Abstract:

GaInAsSb cells probably show better performance than GaSb cells in low-temperature thermophotovoltaic systems due to lower bandgap; however, few experiments proved this phenomenon so far. In this paper, numerical simulation is used to evaluate GaInAsSb and GaSb cells with similar structures under different radiation temperatures. We found that GaInAsSb cells with n-type emitters show slightly higher output power densities compared with that of GaSb cells with n-type emitters below 1,550 K-blackbody radiation, and the power density of the later cells will suppress the formers above this temperature point. During the temperature range of 1,000~2,000 K, the efficiencies of GaSb cells are about twice of GaInAsSb cells if perfect filters are used to prevent the emission of the non-absorbed long wavelength photons. Several parameters that affect the GaInAsSb cell were analyzed, such as doping profiles, thicknesses of GaInAsSb epitaxial layer and surface recombination velocity. The non-p junctions, i.e., n-type emitters are better for GaInAsSb cell fabrication, which is similar to that of GaSb cells.

Keywords: thermophotovoltaic cell, GaSb, GaInAsSb, diffused emitters

Procedia PDF Downloads 281

Authors: X. S. Wu, H. Jia, P. H. Qian, Z. Zhang, H. L. Cai, F. M. Zhang

Abstract:

A bipolar resistance switching behaviour is detected for a Ti/TiO2-x/Au memristor device, which is fabricated by a masked designed magnetic sputtering. The current dependence of voltage indicates the curve changes slowly and continuously. When voltage pulses are applied to the device, the set and reset processes maintains linearity, which is used to simulate the synapses. We argue that the conduction mechanism of the device is from the oxygen vacancy channel model, and the resistance of the device change slowly due to the reaction between the titanium electrode and the intermediate layer and the existence of a large number of oxygen vacancies in the intermediate layer. Then, Hopfield neural network is constructed to simulate the behaviour of neural network in image processing, and the accuracy rate is more than 98%. This shows that titanium dioxide memristor has a broad application prospect in high performance neural network simulation.

Keywords: memristor fabrication, neuromorphic computing, bionic synaptic application, TiO₂-based

Procedia PDF Downloads 90

Authors: Malik Imran Afzal

Abstract:

Cadmium supplied nanowires have unique electrical and optical properties and applications. To obtain cadmium supplied nanowires with regular and good aspect ratio, they can be synthesized by template synthesis method. Porous anodized aluminum oxide is the most promising template with regular hexagonal shapes. Their aspect ratio can be controlled by controlling the pores’ depth and diameter which greatly depend on anodization voltage and temperature of the electrolyte. In this research, high purity aluminium was used to prepare nanotemplates at 5-6°C in 1M phosphoric acid and cadmium supplied was deposited electrochemically using a co-solution of thiourea, cadmium acetate and ammonium acetate. pH was maintained at 11 in a heat bath at 75°C with the help of aqueous ammonia solution. Both porous anodized alumina and cadmium supplied nanowires were characterized suing SEM. A good quality Nanowires were obtained in bunches with reasonably high aspect ratio.

Keywords: bunches, electrodeposition, hexagonal, thiourea

Procedia PDF Downloads 329