22 research outputs found
Electrical and Structural Properties of Aluminium Doped tin Oxide Codoped with Sulphur for Solar Energy
No full textAbstractThin films of Tin Oxide co-doped with 28 atomic percentages of Aluminium (i.e. 28 at% Al) and varied concentration of Sulphur were prepared on 1mm thick, 1cm by 1cm glass substrates at 470 0C by Spray Pyrolysis technique. Films were produced from 2.0M solution of hydrous Tin Chloride dissolved in Ethanol with 38% Hydrochloric acid concentration, 1.5M aqueous Aluminium chloride and 2.0M aqueous solution of Ammonium Sulphide. The effects of Sulphur concentration on structural and electrical properties of transparent Tin Oxide thin films were investigated in the atomic percentage of Sulphur content ranging from zero to fifty (i.e. 0at%S -50at%S) with a fixed 28at%Al content. Polycrystalline structures without any second phases were observed with preferential orientations along the (110), (101), (200) and (211) planes. The average grain size as determined from the (110) peaks lay in the range 19.2 nm-47.7nm. The minimum resistivity was found to be 1.15x10-3Ωcm for the Tin Oxide films doped with 32 at% Al content and 9.59x10-3Ωcm for Tin Oxide films co-doped with 28 at% Al and 20 at% S content. It was observed that Aluminium doping lowered the grain size significantly but doping to optimum level of 32 at% Al content increases electrical conductivity of tin oxide. When Sulphur was intentionally introduced in the crystal structure of 28 at% Al doped Tin Oxide, the electrical conductivity decreased appreciably and the grain size increased
Tem study of microstructure in relation to hardness and ductility in Al-Mg-Si (6xxx) alloys
No full textTwo different solution heat treatments (2hours at 570ºC and 10minutes at 520ºC) have been used to study precipitation in two 6xxx (Al-Mg-si) dispersoid-freealloys with composition: 0.721 at % Si, 0.577 at % Mg (alloy A3) and 0.57 at %Si 0.72 at % Mg (alloy A12). The relation between their microstructure and macroscopical properties such as hardness and ductility has been investigated. Tensile tests, hardness measurements, electrical conductivity sigma tests, grain size measurements in optical microscope and microstructure characterization in Transmission Electron Microscope (TEM) have all been done. The effect of alloy composition and solution heat treatment temperature and time on the microstructure and the resulting macroscopical properties (hardness, yield stress, tensile strength and ductility) was investigated. The results indicate that when alloy A3 is solution treated at 520ºC for 10 minutes and then annealed for 3 hours at 175ºC, its hardness, yield stress and tensile strength as well as ductility is optimised i.e.A3 has better mechanical properties and low cost of production at these conditions. It has been proved that the strengthening was solely due to precipitation particles and not grain size
Tem study of microstructure in relation to hardness and ductility in Al-Mg-Si (6xxx) alloys
No full textTwo different solution heat treatments (2hours at 570ºC and 10minutes at 520ºC) have been used to study precipitation in two 6xxx (Al-Mg-si) dispersoid-freealloys with composition: 0.721 at % Si, 0.577 at % Mg (alloy A3) and 0.57 at %Si 0.72 at % Mg (alloy A12). The relation between their microstructure and macroscopical properties such as hardness and ductility has been investigated. Tensile tests, hardness measurements, electrical conductivity sigma tests, grain size measurements in optical microscope and microstructure characterization in Transmission Electron Microscope (TEM) have all been done. The effect of alloy composition and solution heat treatment temperature and time on the microstructure and the resulting macroscopical properties (hardness, yield stress, tensile strength and ductility) was investigated. The results indicate that when alloy A3 is solution treated at 520ºC for 10 minutes and then annealed for 3 hours at 175ºC, its hardness, yield stress and tensile strength as well as ductility is optimised i.e.A3 has better mechanical properties and low cost of production at these conditions. It has been proved that the strengthening was solely due to precipitation particles and not grain size
Biogas Production from Biomass Kitchen Waste Laced with Cow Dung in a Modified Laboratory - Scale Anaerobic Digester
No full textAnaerobic digestion is an effective method for organic pollution reduction and bio-energy production and has increasing applications worldwide. Produced biogas consists mainly of 50–70% methane and 30–50% carbon dioxide. The most common utilization route of biogas is for electricity production, often combined with utilization of the excess heat. This widens up the opportunities to utilize biogas in distant energy consumption locations. The study sort to design, build a laboratory-scale biogas digester and test and optimize the gas production from different types of organic kitchen wastes. Biomass Kitchen waste was collected, as feedstock for a laboratory-scale anaerobic digester (10L capacity) to produce biogas. This was done within a temperature range of 25°C - 35°C and in an alkaline environment maintained by adding a medium of sodium hydroxide. It was set to operate at constant gas pressure. The study has shown that using the displacement of water method in an inverted siphon system, we can sustain high pressure of the stored gas. The same idea can be used to pump this biogas to places far away from the digester for consumption. The biogas produced was then analyzed for its energy potential. The power potential of biogas produced by co-digesting kitchen waste and cow dung was found to be 22,461.77W/m3. Pure methane has a power potential of 37,258.9W/m3. Therefore, the methane percentage in the biogas collected in this study was 60.29%. The gas was also taken through gas chromatography to assess its constituents. Cow dung and starch were found to produce a higher percentage of methane. It is envisaged that the gas generated and the process friendly cost, will be a perfect alternative source of cleaner, safer and cheaper energy source as compared to the expensive and environmentally unfriendly traditional sources such as firewood, charcoal and petroleum products. This has great domestic and commercial application if exploited.
 
Optical and Thermal Characterization of Energy-Efficient Windows in Anhui District in China
No full textComparative study of crystallization kinetics and phase segregation of triple cation and methylammonium lead iodide perovskites on moisture probing using synchrotron X-ray based radiation
No full text3D mixed perovskites have achieved substantial success in boosting solar cell efficiency, but the complicated perovskite crystal formation pathway remains mysterious. Here we present detailed crystallization kinetics of mixed perovskites FA0.83MA0.17Pb(I0.83Br0.17)3, where FA is formamidinium and MA is methylammonium, with the addition of Cs+ to form a triple cation perovskite (3-CAT), in a comparison with the perovskite building block MAPbI3 (MAPI) via static grazing-incidence wide-angle X-ray scattering (GIWAXS) and micro-diffraction measurements. Spin-coated films produced α-perovskite peaks with no PbI2 or δ-intermediate phases, which was a promising result for the 3-CAT perovskite from micro-diffraction measurements. However, the 3-CAT did not remain stable on probing with varied relative humidity (RH) conditions as segregation back to the δ-intermediate and PbI2 phase after 10 s of exposure to an RH value of 11% was found to occur from the GIWAXS results. When RH levels were elevated to over 100%, segregation peaks of PbI2 and δ-intermediate (2H, 4H and 6H) became conspicuous as the α-phase intensity diminished, unlike for MAPI that remains relatively stable. The possible cause of this is hydrophilic bonds that form between the 3-CAT crystals and the small annealing window of the best composition perovskite (5% Cs+) film
Energy Evaluation and Qualitative Analysis of Biogas Produced from Co-Digesting Kitchen Waste and Cow Dung
No full textNumerical study of copper antimony sulphide (CuSbS2) solar cell by SCAPS-1D
No full textCopper antimony sulphide thin films are promising, less toxic, and more absorbent material in the world, and they would be good to be applied in photovoltaic energy production. To better operations of copper antimony sulphide (CuSbS2) photovoltaic cells, this paper uses a solar cell capacitance simulator (SCAPS-1D) to simulate and analyze photovoltaic properties. This article examines different thicknesses of fluorine-doped tin oxide (FTO), cadmium sulphide (CdS), carbon (C), and CuSbS2, as well as the defect and dopant concentration in the CuSbS2 photoactive layer of the photovoltaic cell structure glass/FTO/n-CdS/p-CuSbS2/C/Au. Optimum thicknesses of CuSbS2 is 300 nm, carbon hole transport layer (HTL) is 50 nm, and for n-CdS electron transport layer (ETL) is 100 nm, giving open circuit Voltage (Voc) of 0.9389 V, short circuit current density (Jsc) of 28.32 mA/cm2, fill factor (FF) of 60.8% and solar cell efficiency of 16.17%. The increase in defects causes a decrease of carrier lifetime resulting in to decrease in diffusion length and the optimum absorber layer doping concentration was found to be 1018 cm−3
Thermodynamic Stability of ABX Heavy Elements of TaIrGe, TiIrSb, TaIrSn and ZrIrSb TCOs Using the Half-Heusler Technique
No full textAbstractElectronic structure theory has recently been used to propose hypothetical compounds in presumed crystal structures, seeking new useful functional materials. The functional materials include transparent conductors needed in solar cell, light emitting diode and flat panel displays, which represent the usually contraindicated functionalities of optical transparency (generally associated with electrical insulators) coexisting with electrical conductivity (generally associated with optically opaque metals). Usually, such hypothetical materials are meta-stable, albeit with technologically useful long lifetimes. Yet, in other cases, suggested hypothetical compounds may be significantly higher in energy than their lowest-energy crystal structures or competing phases, making their synthesis and eventual device-stability questionable. Shifting focus from the previous searches of doping wide-gap metal oxides turns our focus to the newly predicted never before synthesized ABX compounds of TiIrSb, TaIrSn and ZrIrSb called “filled tetrahedral structure” (sometimes called Half-Heusler). We give interest to these compounds because; there stability range is located around X-richest and A/B-poor growth. The ‘inverse design’ principles are applied to ABX compounds. Then the effect of atomic number in their materials to tolerance of sufficient level of off-stoichiometry in creation of free holes that avoid the ionic sites and thus lead to high hole mobility at room temperature
