Optimization of antireflection coating design using pc1d simulation for c − si solar cell application

Minimizing the photon losses by depositing an anti-reflection layer can increase the conversion efficiency of the solar cells. In this paper, the impact of anti-reflection coating (ARC) for enhancing the efficiency of silicon solar cells is presented. Initially, the refractive indices and reflectance of various ARC materials were computed numerically using the OPAL2 calculator. After which, the reflectance of SiO2, TiO2, SiNx with different refractive indices (n) were used for analyzing the performance of a silicon solar cells coated with these materials using PC1D simulator. SiNx and TiO2 as single-layer anti-reflection coating (SLARC) yielded a short circuit current density (Jsc ) of 38.4 mA/cm2 and 38.09 mA/cm2 respectively. Highest efficiency of 20.7% was obtained for the SiNx ARC layer with n = 2.15. With Double-layer anti-reflection coating (DLARC), the Jsc improved by ∼0.5 mA/cm2 for SiO2 /SiNx layer and hence the efficiency by 0.3%. Blue loss reduces significantly for the DLARC compared with SLARC and hence increase in Jsc by 1 mA/cm2 is observed. The Jsc values obtained is in good agreement with the reflectance values of the ARC layers. The solar cell with DLARC obtained from the study showed that improved conversion efficiency of 21.1% is obtained. Finally, it is essential to understand that the key parameters identified in this simulation study concerning the DLARC fabrication will make experimental validation faster and cheaper

HIV Transmission Potential Among Local and Migrant Factory Workers in Kolkata, India

Migrant workers in India play a key role in the spread of HIV. Kolkata is a common destination for workers, who may acquire infection and transmit it to their wives and/or other sexual partners. We investigated sexual relations and condom use by factory workers. Migrant and local factory workers were randomly selected from five wards of Kolkata. Information was collected about demographic and socio-economic characteristics, sexual relationships, condom usage, and perceptions and intent to use condoms. Condom use was very low in both groups of workers, particularly among migrants. Many married workers visited female sex workers but never used condoms. Few intended to use condoms, and if they did, it did not always translate into actual usage. There is great potential for transmission of HIV/sexually transmitted infections by these workers. Carefully designed intervention and education programs in the context of low literacy and cultural norms are urgently needed

Numerical prediction on the dispersion of pollutant particles

The increasing concern on air pollution has led people around the world to find more efficient ways to control the problem. Air dispersion modeling is proven to be one of the alternatives that provide economical ways to control the growing threat of air pollution. The objective of this research is to develop a practical numerical algorithm to predict the dispersion of pollutant particles around a specific source of emission. The source selected was a rubber wood manufacturing plant. Gaussian-plume model were used as air dispersion model due to its simplicity and generic application. Results of this study show the concentrations of the pollutant particles on ground level reached approximately 90µg/m3, compared with other software. This value surpasses the limit of 50µg/m3 stipulated by the National Ambient Air Quality Standard (NAAQS) and Recommended Malaysian Guidelines (RMG) set by Environment Department of Malaysia. The results also show high concentration of pollutant particles reading during dru seasons as compared to that of rainy seasons. In general, the developed algorithm is proven to be able to predict particles distribution around emitted source with acceptable accuracy

HEAVY METAL LEVELS IN THREE MAJOR CARPS (CATLA CATLA, LABEO ROHITA AND CIRRHINA MRIGALA) FROM THE RIVER RAVI, PAKISTAN

The present study was conducted to determine heavy metal (cadmium and chromium) concentrations in gills, kidneys, liver, skin, muscles and scales of three fish species (Catla catla, Labeo rohita and Cirrhina mrigala) from three stations viz. Lahore Siphon (Up stream), Shahdera Bridge and Baloki Headworks (Down stream) in the river Ravi, Pakistan. Heavy metal concentrations varied significantly depending upon the type of fish tissues and locations. The concentrations of cadmium and chromium differed significantly (p<0.001) among five fish organs and three sites and non-significantly between the three fish species. Fish liver appeared to have significantly higher tendency for the accumulation of cadmium and chromium (4.26 ± 1.57 and 6.23 ± 1.14 µgg-1), while gills had minimum concentrations (1.10 ± 0.53 and 1.46 ± 0.52 µgg-1) of these metals. Generally, Catla catla showed higher levels of metal concentrations than Labeo rohita and Cirrhina mrigala. Metal contamination was highest at Baloki Headworks, probably due to inclusion of more effluents from industrial and sewage water

Optimization of stack emission parameters using gaussian plume model

Numerical simulation is an economical way to control air pollution because of its consistency and ease of use compared to traditional data sampling method. The objective of this research is to develop a practical numerical algorithm to predict the dispersion of pollutant particles around a specific source of emission. The algorithm is tested with a rubber wood manufacturing plant. Gaussian-plume model were used as air dispersion model due to its simplicity and generic application. Results of this study show the concentrations of the pollutant particles on ground level reached approximately 90μg/m3, compared with other software. This value surpasses the limit of 50μg/m3 stipulated by the National Ambient Air Quality Standard (NAAQS) and Recommended Malaysian Guidelines (RMG) set by Environment Department of Malaysia. The manufacturing plant is advised to make a few changes with its emission parameters and adequate values are suggested. In general, the developed algorithm is proven to be able to predict particles distribution around emitted source with acceptable accuracy

Control Law Design for Twin Rotor MIMO System with Nonlinear Control Strategy

Modeling of complex air vehicles is a challenging task due to high nonlinear behavior and significant coupling effect between rotors. Twin rotor multi-input multioutput system (TRMS) is a laboratory setup designed for control experiments, which resembles a helicopter with unstable, nonlinear, and coupled dynamics. This paper focuses on the design and analysis of sliding mode control (SMC) and backstepping controller for pitch and yaw angle control of main and tail rotor of the TRMS under parametric uncertainty. The proposed control strategy with SMC and backstepping achieves all mentioned limitations of TRMS. Result analysis of SMC and backstepping control schemes elucidates that backstepping provides efficient behavior with the parametric uncertainty for twin rotor system. Chattering and oscillating behaviors of SMC are removed with the backstepping control scheme considering the pitch and yaw angle for TRMS

Effects of SiO2 and ZnO Nanoparticles on Epoxy Coatings and Its Performance Investigation Using Thermal and Nanoindentation Technique

Synergistic formulations were developed with nano-pigments, and their effects on the mechanical properties on steel substrates and structures were evaluated. This paper provides a complete analysis of the epoxy coating, focusing on the incorporation of nano-pigments and their synergistic effects in obtaining higher mechanical properties. This study reports the preparation of epoxy nano-silica composites, their characterization, and the development of coatings based on nano-silica and ZnO particles. In this composite, epoxy resin was incorporated with SiO2 as the main pigment and ZnO as a synergistic pigment to achieve high-performance epoxy coatings for multiple applications. The mechanical properties of these coatings (ESZ1–ESZ3) were evaluated by nanoindentation, and were used to measure the enhanced durability of nanocomposite coatings developed with synergistic formulations with different types of nanoparticles. Their performance was evaluated before and after exposure to a 3.5% NaCl solution to examine the changes of hardness and elastic modulus. The results showed that the nanoindentation technique, in conjunction with Fourier transform infrared spectroscopy and X-ray diffraction, could examine the durability and predict the service life of nanocomposite coatings. A correlation was observed between the modulus and hardness before and after exposing epoxy composite coatings (ESZ1–ESZ3) to a 3.5% NaCl solution

The Structure, Magnetic, and Gas Sensing Characteristics of W-Substituted Co-Ferrite Nanoparticles

Ferrites have been broadly investigated as gas sensors. The present article reports on the synthesis of Co-ferrite doped with W ions and their gas sensing abilities. A series of single phase CoFe2O4 powder with different W-doping (0.0 &le; x &le; 0.15) was synthesized using sol-gel synthesis. A variation in the saturation magnetization (Ms) and the lattice dimension with W(VI) substitution was associated with a change in the distribution of Fe(III) ions between tetrahedral and octahedral sites. Introducing W(VI) ions into the spinel lattice induced the rearrangement of Fe(III) ions. The total Ms increased with W-doping up to x = 0.05 (Ms = 50.1 Am2/kg) and it dramatically decreased to 34.6 Am2/kg with x = 0.15 of doping. However, the lattice parameter increased with increasing doping levels. Different W-doped CoFe2O4 were examined for a gas sensing response in the temperature range of 200&ndash;450 &deg;C. Comparing the sensor responses to various reducing gases, the material&rsquo;s response was shown to be sensitive and selective for acetone. The addition of W (0.15%) had a significant impact on the response and on the operating temperature of the sensor material, indicating that it might be used as an acetone sensor

The Structure, Magnetic, and Gas Sensing Characteristics of W-Substituted Co-Ferrite Nanoparticles

Ferrites have been broadly investigated as gas sensors. The present article reports on the synthesis of Co-ferrite doped with W ions and their gas sensing abilities. A series of single phase CoFe2O4 powder with different W-doping (0.0 ≤ x ≤ 0.15) was synthesized using sol-gel synthesis. A variation in the saturation magnetization (Ms) and the lattice dimension with W(VI) substitution was associated with a change in the distribution of Fe(III) ions between tetrahedral and octahedral sites. Introducing W(VI) ions into the spinel lattice induced the rearrangement of Fe(III) ions. The total Ms increased with W-doping up to x = 0.05 (Ms = 50.1 Am2/kg) and it dramatically decreased to 34.6 Am2/kg with x = 0.15 of doping. However, the lattice parameter increased with increasing doping levels. Different W-doped CoFe2O4 were examined for a gas sensing response in the temperature range of 200–450 °C. Comparing the sensor responses to various reducing gases, the material’s response was shown to be sensitive and selective for acetone. The addition of W (0.15%) had a significant impact on the response and on the operating temperature of the sensor material, indicating that it might be used as an acetone sensor

Fabrication and Characterization of W-Substituted ZnFe2O4 for Gas Sensing Applications

A sol&ndash;gel technique was successfully employed in creating pure and W-substituted zinc ferrite, with nominal compositions of ZnFe2&minus;2xWxO4 (0.0 &le; x &le; 0.15). For the purposes of investigating the physical and chemical properties of the generated powders, several analytical techniques were used. In TEM images of all the compositions, mixed-shaped particles (cubic, spherical, and hexagonal) were observed. The crystallite size decreases from 82 nm (x = 0.0) to 32 nm (x = 0.15) with an increase in the W doping contents in the ZnFe2O4 lattice. The microstrain increases with increasing W doping content. Furthermore, the surface area of pure ZnFe2O4, 0.05 W-ZnFe2O4, 0.10 W-ZnFe2O4, and 0.15 W-ZnFe2O4 NPs were calculated as being 121.5, 129.1, 134.4 and 143.2 m2 g&minus;1, respectively, with a mesoporous pore structure for all ferrite samples. The calculated BJH pore size distribution was within the range of 160 to 205 &Aring;. All W-doped ZnFe2O4 samples show H-M loops with paramagnetic characteristics. The magnetization (M) directly increases by increasing the applied field (H) without achieving saturation up to 20 kA/m. For comparison, the magnetization at 20 kA/m gradually decreases with increasing W doping content. Among all the synthesized samples, the 0.15 W-ZnFe2O4 NPs demonstrated the highest sensitivity towards acetone gas at 350 &deg;C