Simulation Of Natural Gas Combustion Process Using Pressure Based Solver

The aim of this research is to simulate the combustion process for methane using different heat transfer models combined with various fuel injection techniques to better understand the combustion process and heat transfer process inside IC engine which reflect on the engine efficiency. The simulation has been carried out using Lotus Engineering software. This model solves the nonlinear momentum and continuity equations to satisfy the conservation of mass and the conservation of momentum laws. In this analysis a single cylinder four stroke SI engine has been simulated. The fuel used in the simulation is methane. Two fuel systems have been investigated port injection and direct injection. The Wiebe heat release curve has been used. Two widely used for SI engines heat transfer models presented in the simulation, Annand and Woschni. The intension in this paper is to study the effect of various fuel systems and heat transfer models on engine efficiency for different engine speeds. Moreover, the evaluation of the heat transfer models for natural gas SI engine will be tested. Brake power, mean effective pressure, specific fuel consumption, brake thermal efficiency, and heat transfer rate were calculated and discussed to show the effect of varying heat transfer models and fuel systems on engine efficiency

Management of erectile dysfunction post-radical prostatectomy

© 2015 Saleh et al.Radical prostatectomy is a commonly performed procedure for the treatment of localized prostate cancer. One of the long-term complications is erectile dysfunction. There is little consensus on the optimal management; however, it is agreed that treatment must be prompt to prevent fibrosis and increase oxygenation of penile tissue. It is vital that patient expectations are discussed, a realistic time frame of treatment provided, and treatment started as close to the prostatectomy as possible. Current treatment regimens rely on phosphodiesterase 5 inhibitors as a first-line therapy, with vacuum erection devices and intraurethral suppositories of alprostadil as possible treatment combination options. With nonresponders to these therapies, intracavernosal injections are resorted to. As a final measure, patients undergo the highly invasive penile prosthesis implantation. There is no uniform, objective treatment program for erectile dysfunction post-radical prostatectomy. Management plans are based on poorly conducted and often underpowered studies in combination with physician and patient preferences. They involve the aforementioned drugs and treatment methods in different sequences and doses. Prospective treatments include dietary supplements and gene therapy, which have shown promise with there proposed mechanisms of improving erectile function but are yet to be applied successfully in human patients

Cuscuton: A Causal Field Theory with an Infinite Speed of Sound

We introduce a model of scalar field dark energy, Cuscuton, which can be realized as the incompressible (or infinite speed of sound) limit of a scalar field theory with a non-canonical kinetic term (or k-essence). Even though perturbations of Cuscuton propagate superluminally, we show that they have a locally degenerate phase space volume (or zero entropy), implying that they cannot carry any microscopic information, and thus the theory is causal. Even coupling to ordinary scalar fields cannot lead to superluminal signal propagation. Furthermore, we show that the family of constant field hypersurfaces are the family of Constant Mean Curvature (CMC) hypersurfaces, which are the analogs of soap films (or soap bubbles) in a Euclidian space. This enables us to find the most general solution in 1+1 dimensions, whose properties motivate conjectures for global degeneracy of the phase space in higher dimensions. Finally, we show that the Cuscuton action can model the continuum limit of the evolution of a field with discrete degrees of freedom and argue why it is protected against quantum corrections at low energies. While this paper mainly focuses on interesting features of Cuscuton in a Minkowski spacetime, a companion paper (astro-ph/0702002) examines cosmology with Cuscuton dark energy.Comment: 11 pages, 1 figure, added discussion of "coupled cuscuton", matches the published version in PR

Do Large-Scale Inhomogeneities Explain Away Dark Energy?

Recently, new arguments (astro-ph/0501152, hep-th/0503117) for how corrections from super-Hubble modes can explain the present-day acceleration of the universe have appeared in the literature. However, in this letter, we argue that, to second order in spatial gradients, these corrections only amount to a renormalization of local spatial curvature, and thus cannot account for the negative deceleration. Moreover, cosmological observations already put severe bounds on such corrections, at the level of a few percent, while in the context of inflationary models, these corrections are typically limited to ~ 10^{-5}. Currently there is no general constraint on the possible correction from higher order gradient terms, but we argue that such corrections are even more constrained in the context of inflationary models.Comment: 4 Pages, no figures. Minor modifications, added reference

Pathways to Family Success Final Evaluation Report

This report presents findings from the second year of the evaluation of the Pathways to Family Success Programs (PFS) funded by the Department of Elementary and Secondary Education (ESE) and conducted by the Center for Social Policy (CSP) for the period September 2010 through June 2011. The 2010-2011 evaluation aimed to determine the extent to which PFS activities and interventions were effective in supporting learning outcomes and goal attainment for participating families and their children, and to identify strengths and areas of growth for the PFS Programs and partners. There were four Program sites implementing the PFS indepth project during the second year evaluation period. These leading agencies for the PFS sites included the following: Cambridge Community Learning Center Greater Lawrence Community ActionCouncil, Inc. Holyoke Public Schools Berkshire Children and Families, Inc. The evaluation design involved gathering information on three different outcome levels: the first level includes outcomes for adults, children and families; the second includes outcomes at the program level, and the third focuses on outcomes for the community partnership as a whole. The evaluation utilized a mixed-method approach including both qualitative and quantitative methods and a range of data sources to answer the research questions related to the PFS indepth projects and community partnerships. The evaluation team also conducted case studies of a sample of Pathways Families by interviewing two families from each Pathways site at two points in time