Fluorescence spectroscopy has been utilised to characterise ghee extracted from buffalo and cow milk. Using an excitation wavelength of 320 nm, emission spectra of buffalo and cow ghee; vitamins A, B12, D, E, K; and conjugated linoleic acid (CLA) were acquired by using spectrofluorometer. The bands at 390, 440, 480 and 525 nm were assigned to fat‐soluble vitamins, CLA, vitamin A and beta‐carotene. Moreover, spectra of vitamins and CLA confirmed their presence in both ghee types. The spectral differences were highlighted through principle component analysis that has been applied for the detection of adulteration of cow milk in buffalo ghee. 相似文献
Research on and use of biodiesels for engines is growing continuously in the present era. Compression ignition (CI) engine performance for biodiesels of blends B20 from Acid oil, Mahua oil, and Castor oil is experimentally investigated. The engine performance analysis in the form of brake‐specific fuel consumption, brake‐specific energy consumption, brake thermal efficiency (BTE), exhaust gas temperature (EGT), and air fuel ratio are compared with diesel as base fuel. Emission characteristics like CO, CO2, NOx, and opacity are comparatively studied in detail for the considered biodiesels. The entire study is compared with the performance of engine when pure diesel is chosen as fuel. From the complete analysis it was observed that the BTE was higher for Acid oil and Mahua oil among the biodiesels used. And regarding CO emissions, Mahua oil showed lower effect than other biodiesels. Upto 6% increase in EGT of Mahua oil was obtained at no load and for other loads the percent reduced. For all the biodiesels the % enhancement in Co, CO2, and NOx was more than 60% at highest load compared with diesel. 相似文献
Micro-tubular, solid oxide fuel cells consisting of nickel, yttria-stabilized zirconia (Ni-YSZ) anode, yttria-stabilized zirconia (YSZ) electrolyte and lanthanum strontium cobaltite ferrite-gadolinium doped ceria (LSCF-GDC) cathode have been developed and operated under single-chamber conditions, utilizing methane/air mixture. The cell performance was compared with a silver modified cathode by the addition of 10wt% silver-paste in LSCF-GDC cathode. The cells with and without silver addition yielded maximum power densities of 118.75 mW cm−2 and 61.53 mW cm−2 at 700 °C, respectively. The results demonstrate that silver is a good candidate for enhancing the oxidation reduction kinetics via improved adsorption, desorption, dissociation and subsequent diffusion. However, long term performance of the silver modified cathode is not guaranteed under single-chamber conditions. 相似文献
This paper presents a combined experimental and computational study into the aerodynamics and performance of a small scale vertical axis wind turbine (VAWT). Wind tunnel tests were carried out to ascertain overall performance of the turbine and two- and three-dimensional unsteady computational fluid dynamics (CFD) models were generated to help understand the aerodynamics of this performance.Wind tunnel performance results are presented for cases of different wind velocity, tip-speed ratio and solidity as well as rotor blade surface finish. It is shown experimentally that the surface roughness on the turbine rotor blades has a significant effect on performance. Below a critical wind speed (Reynolds number of 30,000) the performance of the turbine is degraded by a smooth rotor surface finish but above it, the turbine performance is enhanced by a smooth surface finish. Both two bladed and three bladed rotors were tested and a significant increase in performance coefficient is observed for the higher solidity rotors (three bladed rotors) over most of the operating range. Dynamic stalling behaviour and the resulting large and rapid changes in force coefficients and the rotor torque are shown to be the likely cause of changes to rotor pitch angle that occurred during early testing. This small change in pitch angle caused significant decreases in performance.The performance coefficient predicted by the two dimensional computational model is significantly higher than that of the experimental and the three-dimensional CFD model. The predictions show that the presence of the over tip vortices in the 3D simulations is responsible for producing the large difference in efficiency compared to the 2D predictions. The dynamic behaviour of the over tip vortex as a rotor blade rotates through each revolution is also explored in the paper. 相似文献
Carbon nanotubes (CNTs) hold the promise of delivering exceptional mechanical properties and multi-functional characteristics. Ever-increasing interest in applying CNTs in many different fields has led to continued efforts to develop dispersion and functionalization techniques. To employ CNTs as effective reinforcement in polymer nanocomposites, proper dispersion and appropriate interfacial adhesion between the CNTs and polymer matrix have to be guaranteed. This paper reviews the current understanding of CNTs and CNT/polymer nanocomposites with two particular topics: (i) the principles and techniques for CNT dispersion and functionalization and (ii) the effects of CNT dispersion and functionalization on the properties of CNT/polymer nanocomposites. The fabrication techniques and potential applications of CNT/polymer nanocomposites are also highlighted. 相似文献
Lanthanum titanate (La2Ti2O7) with perovskite-like layered structure is a candidate material for high temperature sensor application due to its high curie temperature (Tc?=?1461 °C) and linearity of temperature vs. electrical resistance. La2Ti2O7 (LTO) was synthesized by solid state reaction using constituent powders at 1250 °C for 2 h. The LTO samples prepared in the form of circular pellets were sintered in temperature ranges (1350 to 1400 °C for 2 h). The sintered density was found highest at 1400 °C for LTO samples (>?97.24% Th.). Moreover, the sintered LTO samples were characterized for their ferroelectric properties as well as DC electrical resistivity (ρ) measured in the temperature range of 100 to 900 °C. The electrical resistivity was decreased from 1013 to 106 Ω cm linearly with the increase in temperature from 100 to 900 °C. Hence, LTO is a promising sensor material for high temperature applications.