An experimental technique to measure the shunt resistance across a local region of a floating junction

The inclusion of a floating junction (FJ) at the surface of a solar cell is one way to obtain good-quality surface passivation. The development of FJ-passivated solar cells, however, has been hindered by the frequent occurrence of shunting across the FJ. Shunting can occur at specific regions of the FJ, such as at isolated points of the base contact or at the edges of the solar cell. This paper presents an experimental technique to determine the shunt resistance across local regions of an FJ, thereby providing a means to compare the prevalence of shunting in one region to another. By locating and quantifying the shunting in specific regions of an FJ, valuable insight into its cause can be obtained.     

Effects of frying on the fatty acid composition in farmed and wild gilthead sea bream (Sparus aurata)

The effects of frying in soybean (FWSO) and olive oils (FWOO) on the fatty acid composition of farmed and wild gilthead sea bream Sparus aurata were evaluated. The fat content increased with both frying treatments. However, after FWOO the moisture content of the fish was reduced to a greater extent than that in fish FWSO. The concentration of saturated fatty acids (SFA) decreased significantly during both frying processes ( P  < 0.01). However, the concentration of monounsaturated fatty acids (MUFA) increased significantly in fish fried in olive oil ( P  < 0.01). The fried fish contained a higher level of n-6 polyunsaturated fatty acids (PUFA) and a lower level of n-3 PUFA compared to raw fish. The n-3/n-6 ratio decreased in wild fish FWSO and FWOO from 0.94 ± 0.08 to 0.15 ± 0.01 and 0.15 ± 0.02, respectively. In farmed bream, the ratios decreased from 2.51 ± 0.03 to 0.18 ± 0.03 and 0.36 ± 0.01, respectively. The concentration of trans fatty acids decreased significantly in both fish types after frying ( P  < 0.05). The frying process widely affected the EPA and DHA content, limiting the positive effects of n-3 PUFA.     

Effect of flour fortification with haem liposome on bread and bread doughs

Slaughter blood haem was encapsulated in lecithin : cholesterol Liposomes. Wheat flour was fortified with this mixture at two levels (60 and 100 mg/100 g flour) using the haem liposomes as iron source. The effect of haem fortification on gluten and fat content of flours was determined, as were the effects of fortification on dough visco‐elastic characteristics (water absorption, development time, dough stability and breakdown time). The baking properties of the breads were also investigated. The addition of haem liposomes increased the fat content of flours, and had a positive effect on the stability and rheological characteristics of the dough. Loaf volume and crumb uniformity was improved. These results indicate a potential nutritional use for haem liposomes..     

Efficient Deep CNN Model for COVID-19 Classification

Coronavirus (COVID-19) infection was initially acknowledged as a global pandemic in Wuhan in China. World Health Organization (WHO) stated that the COVID-19 is an epidemic that causes a 3.4% death rate. Chest X-Ray (CXR) and Computerized Tomography (CT) screening of infected persons are essential in diagnosis applications. There are numerous ways to identify positive COVID-19 cases. One of the fundamental ways is radiology imaging through CXR, or CT images. The comparison of CT and CXR scans revealed that CT scans are more effective in the diagnosis process due to their high quality. Hence, automated classification techniques are required to facilitate the diagnosis process. Deep Learning (DL) is an effective tool that can be utilized for detection and classification this type of medical images. The deep Convolutional Neural Networks (CNNs) can learn and extract essential features from different medical image datasets. In this paper, a CNN architecture for automated COVID-19 detection from CXR and CT images is offered. Three activation functions as well as three optimizers are tested and compared for this task. The proposed architecture is built from scratch and the COVID-19 image datasets are directly fed to train it. The performance is tested and investigated on the CT and CXR datasets. Three activation functions: Tanh, Sigmoid, and ReLU are compared using a constant learning rate and different batch sizes. Different optimizers are studied with different batch sizes and a constant learning rate. Finally, a comparison between different combinations of activation functions and optimizers is presented, and the optimal configuration is determined. Hence, the main objective is to improve the detection accuracy of COVID-19 from CXR and CT images using DL by employing CNNs to classify medical COVID-19 images in an early stage. The proposed model achieves a classification accuracy of 91.67% on CXR image dataset, and a classification accuracy of 100% on CT dataset with training times of 58 min and 46 min on CXR and CT datasets, respectively. The best results are obtained using the ReLU activation function combined with the SGDM optimizer at a learning rate of 10⁻⁵ and a minibatch size of 16.     

Correlation between the physical properties and the novel applications of Mg<Subscript>0.7</Subscript>Cu<Subscript>0.3</Subscript>Fe<Subscript>2</Subscript>O<Subscript>4</Subscript> nano-ferrites

Nano-ferrite of the general formula Mg_0.7Cu_0.3Fe₂O₄ was prepared by citrate-gel auto combustion method. The structure was studied by X-ray diffraction, Brunauer–Emmet–Teller, field emission scanning electron microscopy and energy dispersive X-ray spectroscopy analyses. The crystallite size of the investigated nano ferrite was ?39 nm. The magnetic hysteresis measurements at different temperatures (100, 170, 240, and 300 K) were performed using a vibrating sample magnetometer. A correlation between magnetic behavior and lattice strain has been established. Arrott plot has been employed to understand the magnetic behavior of nano-crystalline Mg_0.7Cu_0.3Fe₂O₄. The magnetic susceptibility was carried out using Faraday’s method. Magnetic constants such as Curie temperature, effective magnetic moment, saturation magnetization, and coercivity were obtained and reported. Based on UV diffuse reflectance spectroscopy studies, the optical band gaps are in the range from (1.3–1.9 eV), hence the investigated samples could act as visible light driven photo catalysts.     

Characterization of nanocellulose from Indica rice straw as reinforcing agent in epoxy-based nanocomposites

The extraction of nanocellulose from agro-waste have received wide attention in nanocomposite technologies. This research unravels physico-chemical characteristics of cellulose from Malaysia Indica rice straw, and the derived cellulose nanocrystal (CNC) by hydrochloric acid (HCl) hydrolysis. The CNC was subjected to field emission scanning electron microscopy (FESEM) and/or transmission electron microscopy (TEM) and Fourier transformed infrared (FTIR) studies. Furthermore, X-ray diffraction (XRD) and small-angle X-ray scattering (SAXS) were compared with TEM for the CNC lateral crystal size. Subsequently, CNC reinforced epoxy laminates for Kevlar were prepared and tested for their tensile properties. While FTIR analysis confirmed the monoclinic cellulose structure of the isolated CNC, XRD, and SAXS were compared with TEM for the CNC lateral crystal size. Hydrolysis of the cellulose sample yielded 40.87% of CNC with 4.8 nm in width and a needle-shaped nature. The extracted CNC has relatively low crystallinity (56.12%) but interestingly low crystallite size with an average crystallite size of 1.69 nm (XRD) and 4.18 nm (SAXS). Furthermore, an addition of just 1 wt% of CNC to epoxy composite increased the strength of Kevlar by over 300% and the elastic modulus by nearly three-fold. Nanocellulose obtained from rice straw have great potential as reinforcing agents for the manufacture of nanocomposites.     

Biochemical Characterization of New Gemifloxacin Schiff Base (GMFX-o-phdn) Metal Complexes and Evaluation of Their Antimicrobial Activity against Some Phyto- or Human Pathogens

Four novel ligand-metal complexes were synthesized through the reaction of Fe(III), pleaseCo(II), Zn(II), and Zr(IV) with Schiff base gemifloxacin reacted with ortho-phenylenediamine (GMFX-o-phdn) to investigate their biological activities. Elemental analysis, FT-IR, ¹H NMR, UV-visible, molar conductance, melting points, magnetic susceptibility, and thermal analyses have been carried out for insuring the chelation process. The antimicrobial activity was carried out against Monilinia fructicola, Aspergillus flavus, Penicillium italicum, Botrytis cinerea, Escherichia coli, Bacillus cereus, Pseudomonas fluorescens, and P. aeruginosa. The radical scavenging activity (RSA%) was in vitro evaluated using ABTS method. FT-IR spectra indicated that GMFX-o-phdn chelated with metal ions as a tetradentate through oxygen of carboxylate group and nitrogen of azomethine group. The data of infrared, ¹H NMR, and molar conductivity indicate that GMFX–o-phdn reacted as neutral tetra dentate ligand (N₂O₂) with metal ions through the two oxygen atoms of the carboxylic group (oxygen containing negative charge) and two nitrogen atoms of azomethine group (each nitrogen containing a lone pair of electrons) (the absent of peak corresponding to ν(COOH) at 1715 cm⁻¹, the shift of azomethine group peak from 1633 cm⁻¹ to around 1570 cm⁻¹, the signal at 11 ppm of COOH and the presence of the chloride ions outside the complex sphere). Thermal analyses (TG-DTG/DTA) exhibited that the decaying of the metal complexes exists in three steps with the final residue metal oxide. The obtained data from DTA curves reflect that the degradation processes were exothermic or endothermic. Results showed that some of the studied complexes exhibited promising antifungal activity against most of the tested fungal pathogens, whereas they showed higher antibacterial activity against E. coli and B. cereus and low activity against P. fluorescens and P. aeruginosa. In addition, GMFX-o-phdn and its metal complexes showed strong antioxidant effect. In particular, the parent ligand and Fe(III) complex showed greater antioxidant capacity at low tested concentrations than that of other metal complexes where their IC₅₀ were 169.7 and 164.6 µg/mL, respectively.     

Multi-scale numerical simulations of thermal expansion properties of CNT-reinforced nanocomposites

In this work, the thermal expansion properties of carbon nanotube (CNT)-reinforced nanocomposites with CNT content ranging from 1 to 15 wt% were evaluated using a multi-scale numerical approach, in which the effects of two parameters, i.e., temperature and CNT content, were investigated extensively. For all CNT contents, the obtained results clearly revealed that within a wide low-temperature range (30°C ~ 62°C), thermal contraction is observed, while thermal expansion occurs in a high-temperature range (62°C ~ 120°C). It was found that at any specified CNT content, the thermal expansion properties vary with temperature - as temperature increases, the thermal expansion rate increases linearly. However, at a specified temperature, the absolute value of the thermal expansion rate decreases nonlinearly as the CNT content increases. Moreover, the results provided by the present multi-scale numerical model were in good agreement with those obtained from the corresponding theoretical analyses and experimental measurements in this work, which indicates that this multi-scale numerical approach provides a powerful tool to evaluate the thermal expansion properties of any type of CNT/polymer nanocomposites and therefore promotes the understanding on the thermal behaviors of CNT/polymer nanocomposites for their applications in temperature sensors, nanoelectronics devices, etc.     

E-negotiation versus face-to-face negotiation what has changed – if anything?

The focus of the present study is the relatively new and still controversial electronically mediated negotiation (hence denoted e-negotiation) as compared to the good old face-to-face negotiations. The main research question is the impact that the type of negotiation media (face-to-face versus e-negotiation) has on the features of the negotiation process (duration and tactics) and on its outcomes. It also examines the moderation effects of the sequence of the negotiation media, i.e., face-to-face negotiation, when carried out prior to, or after e-negotiation. For this purpose, 80 young students were exposed to the two types of negotiations, whilst various intervening variables were controlled by randomization. It was found that the negotiation media, as well as the negotiation sequence, barely affects the negotiation outcomes. Face-to-face negotiation was not different than e-negotiation, in terms of the final price, the number of installments for the balance and the sum of the advanced payment. However, both the negotiation media and the negotiation sequence significantly affected the main features of the negotiation process, in terms of time duration and the use of hard or soft tactics. These results are discussed and interpreted in terms of existing theories.     

Standard potentials of the silver—silver bromide electrode in dioxane—water mixtures and related thermodynamic functions

The standard potentials of AgAgBr electrode in eighteen dioxane + water solvent mixtures containing up to 90 wt % dioxane, have been evaluated from the emf measurements of the cell Pt, H₂ (g, 1 atm); HBr (m), X % dioxane, Y % water: AgBr, Ag at nine different temperatures in the range 15–55°C. The standard molal potentials in each solvent have been represented as a function of temperature. The standard thermodynamic functions for the cell reaction, the primary medium effects of various solvents upon HBr and the standard thermodynamic quantities for the transfer of one mole of HBr from water to the respective dioxane + water media have been computed and discussed in the light of ion—solvent interactions as well as the structural changes of the solvents.