Diffused junction p+−n solar cells in bulk GaAs—II: Device characterization and modelling

The photovoltaic characteristics of p⁺-n junction solar cells fabricated on bulk GaAs by an open tube diffusion technique are presented in detail. Quantum efficiency measurements were analyzed and compared to computer simulations of the cell structure in order to determine material parameters such as diffusion length, surface recombination velocity and junction depth. From the results obtained it is projected that proper optimization of the cell parameters can increase the efficiency of the cells to close to 20%.     

Thermodynamics study of liquid Cu−Mg alloys by vapor pressure measurements

Metallurgical and Materials Transactions B -     

Studies on transport of vapor and solute molecules through polyvinyl alcohol‐based clay containing nanocomposites

The present study focuses on fabricating of polymer–clay nanocomposites by in situ polymerization method and investigating their permeability behavior toward vapor and liquid molecules, thus, to evaluating barrier properties of the nanocomposites. For this purpose, acrylonitrile (AN) monomer was grafted on to poly(vinyl alcohol) (PVA) chains after the addition of very low amount of fuller's earth (clay) into polymer matrix using a suitable initiator, such as potassium persulphate (KPS), and crosslinker N‐N′ methylene bisacrylamide (MBA). The prepared nanomaterials were characterized by Fourier‐Transformation infrared (FTIR) spectroscopy and wide‐angle X‐ray diffraction (WXRD) techniques. The morphological features of designed materials were studied by scanning electron microscopy. The graft materials impregnated with fuller's earth were examined for their permeability behavior by observing the permeation of solute and vapor molecules from aqueous dye solution and volatile organic solvent, respectively. The composition of the nanocomposites and the amount of fuller's earth content were found to affect the passage of solute and vapor molecules across the nanocomposite membrane. The permeation capacity was quantified by evaluating permeability parameters. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers     

Rheological properties of rennet casein-whey protein gels prepared at different mixing speeds

The rheological properties at small (oscillatory shear) and large (uniaxial compression) deformations of heat-induced gels (80 °C for 20 min, pH 7.3) containing 25% rennet casein (RCN), 2.5% disodium phosphate and 0%, 2.3% or 6.3% of whey protein isolate (WPI) were measured for samples cooked in a torque-rheometer at mixing speeds within a range of 20–200 rpm (shear rates: ∼15–230 s⁻¹). In addition, microstructure analyses were performed, separately staining RCN and WPI, by Confocal Scanning Laser Microscopy (CSLM). Both small and large deformation tests indicated that increasing addition of WPI prior to the cooking process of RCN resulted in gels exhibiting higher storage and deformability moduli than WPI-free samples. Increasing shear rates during cooking also affected the rheological properties of RCN–WPI gels, and stronger gels were formed as the shear rate during cooking was increased. Despite the data dispersion among replicates, the effect of shear rate on gel strength were evident for RCN gels with 6.3% WPI and relatively clear for gels with 2.3% WPI; however, the trend was uncertain for WPI-free RCN gels. Possible explanations for this observation are that when increasing WPI levels in the presence of RCN and heat, disulfide-thiol exchange reactions between denatured WPI and κ-casein (κ-CN) are increased and possibly promoted by shear rate, resulting in stronger and more cross-linked gel structure. CSLM results were not conclusive to support this hypothesis.     

Storage Properties of Low Fat Fish and Rice Flour Coextrudates

In the present study, response surface method (RSM) and genetic algorithm (GA) were used to study the effects of process variables like screw speed, rpm (x ₁), L/D ratio (x ₂), barrel temperature (°C; x ₃), and feed mix moisture content (%; x ₄), on flow rate of biomass during single-screw extrusion cooking. A second-order regression equation was developed for flow rate in terms of the process variables. The significance of the process variables based on Pareto chart indicated that screw speed and feed mix moisture content had the most influence followed by L/D ratio and barrel temperature on the flow rate. RSM analysis indicated that a screw speed > 80 rpm, L/D ratio > 12, barrel temperature > 80 °C, and feed mix moisture content > 20% resulted in maximum flow rate. Increase in screw speed and L/D ratio increased the drag flow and also the path of traverse of the feed mix inside the extruder resulting in more shear. The presence of lipids of about 35% in the biomass feed mix might have induced a lubrication effect and has significantly influenced the flow rate. The second-order regression equations were further used as the objective function for optimization using genetic algorithm. A population of 100 and iterations of 100 have successfully led to convergence the optimum. The maximum and minimum flow rates obtained using GA were 13.19 × 10⁻⁷ m³/s (x ₁ = 139.08 rpm, x ₂ = 15.90, x ₃ = 99.56 °C, and x ₄ = 59.72%) and 0.53 × 10⁻⁷ m³/s (x ₁ = 59.65 rpm, x ₂ = 11.93, x ₃ = 68.98 °C, and x ₄ = 20.04%).     

A Compact Semi-circular Slot MIMO Antenna with Enhanced Isolation for Sub-6 GHz 5G WLAN Applications

In this paper, a novel compact semi-circular slot (SCS) 2 × 2 MIMO antenna is presented for 5G NR sub-6 GHz applications with high isolation. The proposed antenna consists of a semi-circular slot in ground plane, U-shaped stub, and 50-ohm microstrip feed line. The novelty of this paper are the Semi-Circular Slot acts a radiator, the port isolation  is enhanced using a simple conductor strip as a neutralization line, very compact in size, low ECC, and good impedance matching. The overall size of the proposed SCS MIMO antenna is 16 mm x 21 mm, and FR4 substrate is used with thickness of 1.6 mm. The two SCS antenna elements are separated by edge-to-edge distance of 1mm (\(=0.019\lambda _{0}\)). The proposed compact MIMO antenna design is simulated using Ansys HFSS. To validate SCS MIMO antenna, a prototype was fabricated and tested. The measured results are attained at 5.5 GHz with isolation greater than 25dB, impedance bandwidth (S11\(<-10\) dB) covers from 5.10 GHz to 5.80 GHz with return loss of ? 39.5 dB. The MIMO antenna parameters, ECC, CCL, TARC, and MEG are studied, and the values are obtained within acceptable limits. The measured and simulated antenna results are almost similar. This compact MIMO antenna is suitable for 5G communications in sub-6 GHz wifi-5 band applications.

     

Liquid gadolinium corrosion study of TaC coating on tantalum

Spectroscopic information of gadolinium isotopes is necessary to exploit the full potential of various isotopes in nuclear and medical applications. Container materials to handle liquid gadolinium during spectroscopic studies is an important aspect. Tantalum carbide (TaC) has excellent stability and also exhibits superior resistance to attack by various reactive actinide metals at high temperature for long durations. Tantalum crucibles with TaC coating were prepared and tested for compatibility against liquid gadolinium at 1673?K upto 14?h in vacuum. Optical microscopy and SEM/EDS investigations were done to evaluate the micro structural features of the coating and the liquid gadolinium attack. Experimental results show that TaC coating exhibits excellent corrosion resistance against liquid gadolinium at 1673?K.     

Cryptographic Lightweight Encryption Algorithm with Dimensionality Reduction in Edge Computing

Edge Computing is one of the radically evolving systems through generations as it is able to effectively meet the data saving standards of consumers, providers and the workers. Requisition for Edge Computing based items have been increasing tremendously. Apart from the advantages it holds, there remain lots of objections and restrictions, which hinders it from accomplishing the need of consumers all around the world. Some of the limitations are constraints on computing and hardware, functions and accessibility, remote administration and connectivity. There is also a backlog in security due to its inability to create a trust between devices involved in encryption and decryption. This is because security of data greatly depends upon faster encryption and decryption in order to transfer it. In addition, its devices are considerably exposed to side channel attacks, including Power Analysis attacks that are capable of overturning the process. Constrained space and the ability of it is one of the most challenging tasks. To prevail over from this issue we are proposing a Cryptographic Lightweight Encryption Algorithm with Dimensionality Reduction in Edge Computing. The t-Distributed Stochastic Neighbor Embedding is one of the efficient dimensionality reduction technique that greatly decreases the size of the non-linear data. The three dimensional image data obtained from the system, which are connected with it, are dimensionally reduced, and then lightweight encryption algorithm is employed. Hence, the security backlog can be solved effectively using this method.     

Development of fermented Hericium erinaceus juice with high content of L‐glutamine and L‐glutamic acid

Fermented plant beverages (FPB) with a high content of desirable principle components are served as functional foods from several years. Hericium erinaceus is famous for its antimicrobial, antioxidant, antihypertensive and antidiabetic nature. Accordingly, the current study was aimed to produce fermented H. erinaceus juice with a high content of L‐glutamine (Gln) and L‐glutamic acid (GA) through lactic acid bacteria (LAB) isolated from fermented Thai foods. LAB isolates were screened and identified the potent protease‐producing bacteria Enterococcus faecalis (G414/1) that facilitate the production of Gln and GA through protein hydrolysis. Box–Behnken design (BBD) and response surface methodology (RSM) were adapted for the optimisation of conditions for the increased production of Gln and GA during fermentation of H. erinaceus. We succeeded with an optimum concentration of cofactor (CaCl₂), pH and temperature for improved protease activity and subsequent Gln and GA production. The ability of isolated E. faecalis strain to produce Gln and GA was demonstrated in this study. Further, upstream processes like strain improvement and media optimisation will direct the way to produce enriched H. erinaceus based FPB.