Monte Carlo study of ion-induced backward and forward secondary electron emission from thin Al foil

A direct Monte Carlo program has been developed to calculate the backward (γ_b) and forward (γ_f) electron emission yields from 20 nm thick Al foil for impact of C⁺, Al⁺, Ar⁺, Cu⁺ and Kr⁺ ions having energies in the range of 0.1-10 keV/amu. The program incorporates the excitation of target electrons by projectile ions, recoiling target atoms and fast primary electrons. The program can be used to calculate the electron yields, distribution of electron excitation points in the target and other physical parameters of the emitted electrons. The calculated backward electron emission yield and the Meckbach factor R = γ_f/γ_b are compared with the available experimental data, and a good agreement is found. In addition, the effect of projectile energy and mass on the longitudinal and lateral distribution of the excitation points of the electrons emitted from front and back of Al target has been investigated.     

Enhanced fracture strain of polypropylene by incorporation of thermoplastic fibres

The incorporation of continuous, uniaxial oriented, nylon and polyethylene terephthalate fibres into isotactic polypropylene leads to the expected increase in tensile strength as predicted by the rule of mixtures. The elongation to break, however, is found to be significantly in excess of those of the fibres and the matrix and increases with fibre volume fraction. The increase in ductility of the composites is attributed to decrease in spherulite size of the polypropylene and to restrained necking of the fibres due to transcrystalline growth at the fibre surface.     

Hybrid Renewable Energy Resources Management for Optimal Energy Operation in Nano-Grid

Renewable energy resources are deemed a potential energy production source due to their cost efficiency and harmless reaction to the environment, unlike non-renewable energy resources. However, they often fail to meet energy requirements in unfavorable weather conditions. The concept of Hybrid renewable energy resources addresses this issue by integrating both renewable and non-renewable energy resources to meet the required energy load. In this paper, an intelligent cost optimization algorithm is proposed to maximize the use of renewable energy resources and minimum utilization of non-renewable energy resources to meet the energy requirement for a nanogrid infrastructure. An actual data set comprising information about the load and demand of utility grids is used to evaluate the performance of the proposed nanogrid energy management system. The objective function is formulated to manage the nanogrid operation and implemented using a variant of Particle Swarm Optimization (PSO) named recurrent PSO (rPSO). Firstly, rPSO algorithm minimizes the installation cost for nanogrid. Thereafter, the proposed NEMS ensures cost efficiency for the post-installation period by providing a daily operational plan and optimizing renewable resources. State-of-the-art optimization models, including Genetic Algorithm (GA), bat and different Mathematical Programming Language (AMPL) solvers, are used to evaluate the model. The study's outcomes suggest that the proposed work significantly reduces the use of diesel generators and fosters the use of renewable energy resources and beneficiates the eco-friendly environment.     

Agarose Hydrogel Beads: An Effective Approach to Improve the Catalytic Activity,Stability and Reusability of Fungal Amyloglucosidase of GH15 Family

This study deals with the immobilization of amyloglucosidase within agarose using method of entrapment. Enzyme was produced from Aspergillus fumigatus KIBGE-IB33 and then partially purified using 40% ammonium sulphate saturation. Using 40 gl^?1 concentration of agarose and adjusting 3.0 mm size of hydrogels, maximum entrapment yield (78%) was obtained. The kinetic behavior was slightly changed after immobilization as reaction time and reaction temperature increases from 5.0 min (soluble) to 10.0 min (immobilized) and 60 °C (soluble) to 65 °C (immobilized), respectively while, pH optima remained same (pH 5.0). Substrate saturation kinetics revealed that K_m was increased from 1.47 to 4.215 mg ml^?1 while, the value of V_max decreased from 947 to 611 kU mg^?1 for soluble and entrapped amyloglucosidase, respectively. The stability profile of amyloglucosidase also significantly improved after entrapment in agarose hydrogels at 50, 60 and 70 °C for 120 min with retention of 77, 59 and 25% residual activity, respectively. Furthermore, the t_1/2 of soluble and immobilized amyloglucosidase at 60 °C was 167 and 375 min respectively. Due to increase in reusability for various subsequent cycles of entrapped amyloglucosidase, about 8.73 mg ml^?1 increase in glucose production was observed as compared to soluble enzyme.

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Preparation of lactose‐free milk by using salt‐fractionated almond (Amygdalus communis) β‐galactosidase

β‐galactosidase was isolated from almond (Amygdalus communis) extract by ammonium sulfate precipitation. Almond proteins precipitated by using ammonium sulfate and then dialysed exhibited 5.3‐fold purification of β‐galactosidase, and the yield of enzyme preparation was 96.5%. The partially purified β‐galactosidase exhibited pH and temperature optima at pH 5.5 and 50 °C, respectively. The enzyme was significantly stable against heat, pH, calcium and magnesium ions and D ‐galactose. The almond β‐galactosidase preparation exhibited over 89% activity even after 2 months storage at 4 °C. Hydrolysis of lactose in milk and whey was performed in a stirred batch process by using this enzyme preparation. These observations indicated that the hydrolysis of lactose increased continuously with time. The enzyme could hydrolyse 94% of lactose in buffer solution and whey whereas 90% of lactose hydrolysis was achieved in milk. The main aim of the present study was to prepare lactose‐free milk, which must be free from contamination, and the process should be inexpensive. Copyright © 2007 Society of Chemical Industry     

Modelling and Simulation of Design Variants for the Development of 4H-SiC Thyristors

Silicon - Wide band-gap semiconductor materials such as SiC have created a contemporaneous worldwide interest in high power electronic applications and boosted the research possibilities....     

Implementation of shooting technique for Buongiorno nanofluid model driven by a continuous permeable surface

The current investigation focuses on the thermal characteristics and heat and mass transfer in the context of their applications. There has been a lot of interest in the utilization of non-Newtonian liquids in various engineering and biological fields. Having such considerable attention on non-Newtonian liquids, the goal is to investigate the flow nature of viscoelastic nanoliquid flow driven by a permeable stretchable surface considering the Buongiorno nanofluid model with suction or injection and mixed convection. This model includes Brownian diffusion, thermophoresis, and radiation effects. The thermal boundary layer theories established the constitutive flow equations, that is, the momentum, diffusion balance, and energy expressions. The established partial differential equations are diminished to dimensionless coupled ordinary differential equations by taking the assistance of proper transformations of nonlinearities. An efficient and validated numerical algorithm is implemented as a computational technique where Mathematica 11.0 environment, a programming tool, is developed for fluid dynamics. The convergence standard had also been recognized for the precision of the relevant parameters by using boundary postulates. The impact of embedded physical quantities of practical interest is examined and offered via the plotted graphs. In addition, the impression of system parameters on drag force, heat, and mass flow coefficient with three-dimensional graphs is also debated.