For a supercapacitor electrode, carbon-based materials have received great attention for their high surface area and stability. In this work, sustainable and cost-effective synthesis of boron-doped activated biomass-derived carbon from the stems of Prosopis juliflora has been reported for supercapacitor applications. The activation by KOH creates pores and boron induces p-type doping in the carbon matrix. The material gave a higher specific capacitance of 307.14 F/g at a current density of 0.5 A/g. The symmetric supercapacitor device delivered 156.29 F/g of specific capacitance with 98.1% of energy efficiency. The observed energy and power densities were 7.81 Wh/Kg and 150 W/Kg, respectively. The device was further studied with stability test for 1000 charge/discharge cycles and showed 98.6% of capacitance retention and 97.9% of coulombic efficiency.
This study paves the way on reducing smoke emission and NOx emissions of research diesel engine by detailing the effect of water addition in biodiesel. Fuel samples were prepared with different concentrations of water in orange peel oil biodiesel (94% waste orange peel oil biodiesel + 4% water + 2% Span 80 (WOPOBDE1) and 90% waste orange peel oil biodiesel + 8% water + 2% Span 80 (WOPOBDE2). Span 80 was employed as a nonionic surfactant, which emulsifies water in biodiesel. Experimental results revealed that the nitrogen oxides and smoke emission of orange peel oil biodiesel emulsion were reduced by 11%–19% and 3%–21%, respectively, compared to that of neat orange peel oil biodiesel (WOPOBD). In addition, the introduction of orange peel oil–water emulsions in the diesel engine considerably reduced the emissions of unburned hydrocarbons and carbon monoxide. The overall hydrocarbon emission of WOPOBDE2 was 12.2% lower than that of WOPOBD and 16.3% lower than that of diesel. The overall CO emission of WOPOBDE2 was 17% lower than that of base fuel (WOPOBD) and 21.8% lower than that of diesel. Experimental results revealed that modified fuel had higher brake thermal efficiency and lower brake specific fuel consumption than that of base fuel at all engine brake power levels. 相似文献
A method for detection of parametric faults occurring in linear analog circuits based on location of poles of the Circuit
Under Test (CUT) is proposed. In the proposed method, the value of each component of the CUT is varied within its tolerance
limit using monte carlo simulation. The upper and lower bounds of magnitude, phase angle, real part and imaginary part of
all poles of the CUT are obtained. While testing, the locations of poles are obtained. If any one or more of the poles lies
outside the tolerance limit then the CUT is declared faulty. The effectiveness of the proposed method is validated through
two benchmark circuits like second order sallenkey band pass filter and fourth order leapfrog low pass filter. 相似文献
The authors analyze the performance of a single-phase AC-AC converter with particular emphasis on the output harmonic content and input voltage utilization. A complete power circuit that makes use of power MOSFETs is given. An analysis of the output waveform shows that its harmonic content is very low. It is also found that the ratio of the switching frequency to the modulating triangular wave, has negligible effect on the harmonic content. Hence, the ratio can be chosen at nominal value of 4 and it is mainly used to control the amplitude of the fundamental component in the output. The only disadvantage of the single-phase AC-AC converter is that the amplitudes of certain harmonic frequencies become abnormally high 相似文献
The assumption of proportional hazards (PH) fundamental to the Cox PH model sometimes may not hold in practice. In this paper, we propose a generalization of the Cox PH model in terms of the cumulative hazard function taking a form similar to the Cox PH model, with the extension that the baseline cumulative hazard function is raised to a power function. Our model allows for interaction between covariates and the baseline hazard and it also includes, for the two sample problem, the case of two Weibull distributions and two extreme value distributions differing in both scale and shape parameters. The partial likelihood approach can not be applied here to estimate the model parameters. We use the full likelihood approach via a cubic B-spline approximation for the baseline hazard to estimate the model parameters. A semi-automatic procedure for knot selection based on Akaike’s information criterion is developed. We illustrate the applicability of our approach using real-life data. 相似文献
A new method to detect component faults in analog circuits is proposed in this paper. Network parameters like driving point
impedance, transfer impedance, voltage gain and current gain are used to detect component faults in analog circuits as these
network parameters are sensitive to the components of the circuit. Using montecarlo simulation each component of the circuit
is varied within its tolerance limit and the minimum and the maximum values of each network parameter are found for fault
free circuit. At the time of testing, the network parameters are found for the injected fault and if any one or more network
parameters is exceeding its predetermined bound limits then the circuit is confirmed faulty. The proposed method is validated
through second order Sallenkey band pass filter and fourth order Chebyshev low pass filter circuits. Numerical results are
presented to clarify the proposed method and prove its efficiency. 相似文献
In this paper, we investigate both the visual realism and the physical accuracy of the 2D mass-spring-damper (MSD) model with
general unstructured triangular meshes for the simulation of rigid cloth. For visual realism, the model should, at a minimum,
bend smoothly under pure bending load conditions. For physical accuracy, it should bend approximately the same amount and
shape as dictated by continuum mechanics. By matching the 2D MSD model with an elastic plate, we obtain a series of constraints
on the parameters of the model. We find that for a 2D unstructured MSD model, it is necessary to apply preloads on the springs
for accurate modeling of bending resistance. By simultaneously applying the constraints for both visual realism and physical
accuracy, we can optimize the parameters of the model to enhance its fidelity. The simulation shows that the deformation of
the optimized MSD model with preload is very close to the result obtained by the finite element method (FEM) under either
point load condition or pressure load condition. With a much smaller computational burden compared with FEM, the optimized
MSD model is especially suitable for real time haptic applications. 相似文献
Summary The monomer reactivity ratios of methyl phenoxymethacrylate (MPMA), methyl p-cresoxymethacrylate (MCMA) and methyl p-nitrophenoxymethacrylate (MNMA) were evaluated both by Fineman-Ross and Kelen-Tüdös methods. The tendency to form alternating copolymers of these monomers is discussed. 相似文献
AbstractBi-fuel conversions are a common alternative fuelling option for mono-fuel gasoline SI vehicles because of the minor vehicle modifications required. In Malaysia, most bi-fuel vehicles are fuelled with compressed natural gas (CNG) and gasoline. However, CNG flame speed is lower than gasoline reducing the power and range of the vehicle when operating on CNG. This situation can be improved by increasing the flame speed via higher swirl generation. A Computational fluid dynamics model is used to analyse swirl generated by dissimilar valve lift (DVL) profiles on the intake valve. A three-dimensional engine simulation shows differences in swirl motion and turbulence between the original symmetric valve lift profile and the DVL. The higher swirl number reduces the turbulence kinetic energy level slightly. The best case profile is selected for further experimental testing. 相似文献