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Exponentially Fitted Variants of the Two-Step Adams-Bashforth Method for the Numerical Integration of Initial Problems
Get PDFIn this paper, we propose new variants of the two-step Adams-Bashforth and the one-step Adams-Moulton methods for the numerical integration of ordinary differential equations (ODEs). The methods are constructed geometrically from an exponentially fitted osculating parabola. The accuracy and stability of the proposed variants is discussed and their applicability to some initial value problems is also considered. Numerical experiments demonstrate that the exponentially fitted variants of the two-step Adams-Bashforth and the one-step Adams-Moulton methods outperform the existing classical two-step Adams-Bashforth and one-step Adams- Moulton methods respectively
Handbook of Cellulosic Ethanol
No full textComprehensive coverage on the growing science and technology of producing ethanol from the world\u27s abundant cellulosic biomass. The inevitable decline in petroleum reserves and its impact on gasoline prices, combined with climate change concerns, have contributed to current interest in renewable fuels. Bioethanol is the most successful renewable transport fuel-with corn and sugarcane ethanol currently in wide use as blend-in fuels in the United States, Brazil, and a few other countries. However, there are a number of major drawbacks in these first-generation biofuels, such as their effect on food prices, net energy balance, and poor greenhouse gas mitigation. Alternatively, cellulosic ethanol can be produced from abundant lignocellulosic biomass forms such as agricultural or municipal wastes, forest residues, fast growing trees, or grasses grown in marginal lands, and should be producible in substantial amounts to meet growing global energy demand. The Handbook of Cellulosic Ethanol covers all aspects of this new and vital alternative fuel source, providing readers with the background, scientific theory, and recent research progress in producing cellulosic ethanol via different biochemical routes, as well as future directions. The seventeen chapters include information on: Advantages of cellulosic ethanol over first-generation ethanol as a transportation fuel; Various biomass feedstocks that can be used to make cellulosic ethanol; Details of the aqueous phase or cellulolysis route, pretreatment, enzyme or acid saccharification, fermentation, simultaneous saccharification fermentation, consolidated bioprocessing, genetically modified microorganisms, and yeasts; Details of the syngas fermentation or thermochemical route, gasifiers, syngas cleaning, microorganisms for syngas fermentation, and chemical catalysts for syngas-to-ethanol conversion; Distillation and dehydration to fuel-grade ethanol; Techno-economical aspects and the future of cellulosic ethanol; Readership: Chemical engineers, chemists, and technicians working on renewable energy and fuels in industry, research institutions, and universities. The Handbook can also be used by students interested in biofuels and renewable energy issues
Hydropower development in Nepal
No full textThis paper provides an overview of a 100 year history of hydropower in Nepal. The importance of hydropower in Nepal is highlighted and major issues that the country has to consider for the development of hydropower have been analysed in detail. It is the only resource available to generate electricity, both for large export projects and small village mini grid projects in almost any part of the country. The challenges of demand and supply fluctuations, mainly due to the seasonal fluctuation of river discharges, are also described. An analysis of river flow trends shows that the impact of river flow has to be analysed river by river, as the trends are not consistent throughout the country. The social and organisational issues and their relationship with the political stability in the country have also been discussed. Crown Copyright © 2013 Published by Elsevier Ltd. All rights reserved
Fluctuating Flow of Thermomicropolar Fluid Past a Vertical Surface
Get PDFThe unsteady free convection boundary layer flow of a thermo-micropolar fluid along a vertical plate has been investigated in this paper. The temperature of the plate is assumed to be oscillating about a mean temperature, θw(x), with small amplitude ε. The governing boundary layer equations are analyzed using straight forward finite difference method. The effects of the material parameters such as micropolar heat conduction parameter, N*, the vortex viscosity parameter, K, on the shear stress,w, surface heat transfer, qw, and the couple-stress, mw, have been investigated
Thermal Convection in a Couple-Stress Fluid in the Presence of Horizontal Magnetic Field with Hall Currents
Get PDFThe thermal stability of a couple-stress fluid is considered to include the effects of uniform horizontal magnetic field and Hall currents. The analysis is carried out within the framework of linear stability theory and normal made technique. For the case of stationary convection, magnetic field has stabilizing effect whereas Hall currents are found to have destabilizing effect on the system. The couple stress, however, has dual character in contrast to its stabilizing effect in the absence of Hall currents. Oscillatory modes are not allowed in the system. Graphs in each case have been plotted by giving numerical values to the parameters, depicting the stability characteristics
Numerical Solution of Some Nonlinear Volterra Integral Equations of the First Kind
Get PDFIn this paper, the solving of a class of the nonlinear Volterra integral equations (NVIE) of the first kind is investigated. Here, we convert NVIE of the first kind to a linear equation of the second kind. Then we apply the operational Tau method to the problem and prove convergence of the presented method. Finally, some numerical examples are given to show the accuracy of the method
Exact Traveling Wave Solutions of Nonlinear PDEs in Mathematical Physics Using the Modified Simple Equation Method
Get PDFIn this article, we apply the modified simple equation method to find the exact solutions with parameters of the (1+1)-dimensional nonlinear Burgers-Huxley equation, the (2+1) dimensional cubic nonlinear Klein-Gordon equation and the (2+1)-dimensional nonlinear Kadomtsev- Petviashvili-Benjamin-Bona-Mahony (KP-BBM) equation. The new exact solutions of these three equations are obtained. When these parameters are given special values, the solitary solutions are obtained
Temporal and spatial trends in air temperature on the Island of Oahu, Hawaii
No full textWe examined trends in minimum and maximum temperatures in the Oahu during the period of past 39 (1969-2007) and 25 (1983-2007) years. We found a strong spatial and temporal variability in the temperature trends on Oahu. During the past 39years, island-wide minimum temperature has increased by 0.17°C/decade and shows a considerable variability in trends at individual location. There was no detectable trend found in maximum temperature over the same time period. The year 1983 was identified as the change point in the island-wide minimum temperature. During the recent 25years annual and summer maximum temperature showed a decline while minimum temperature continued to increase. Trend in diurnal temperature range (DTR) shows a decline during the past 39years with a stronger decreasing trend during the recent 25years. The trend in DTR for Oahu is much higher compared to the global DTR trend indicating a rapid warming in minimum temperature. Extreme temperature indices show a general warming during the past 39years. There has been significant increase in tropical and warm nights at the two urban stations. Maximum temperature generally followed the Pacific Decadal Oscillation (PDO) except the period when there is an increase in Hawaii Rainfall Index (HRI). In contrast, minimum temperature showed better agreement with HRI compared to the PDO, at least up until 1999 after which it showed an increase. Despite the relative cooling in PDO during the recent decade an increase in minimum temperature can be attributed to a decline in HRI. © 2012 Royal Meteorological Society
A New Approach to the Numerical Solution of Fractional Order Optimal Control Problems
Get PDFIn this article, a new numerical method is proposed for solving a class of fractional order optimal control problems. The fractional derivative is considered in the Caputo sense. This approach is based on a combination of the perturbation homotopy and parameterization methods. The control function u(t) is approximated by polynomial functions with unknown coefficients. This method converts the fractional order optimal control problem to an optimization problem. Numerical results are included to demonstrate the validity and applicability of the method
Numerical Algorithm for Analysis of n-ary Subdivision Schemes
Get PDFThe analysis for continuity of limit curves generated by m-point n-ary subdivision schemes is presented for m, n ≥ 2. The analysis is based on the study of corresponding differences and divided difference schemes. A numerical algorithm is introduced which computes the continuity and higher order divided differences of schemes in an efficient way. It is also free from polynomial factorization and division unlike the well-known Laurent polynomial algorithm for analysis of schemes which depends on polynomial algebraic operations. It only depends on the arithmetic operations