Utilization of Used Vegetable Oil as a Biodiesel Fuel

In this study the reusing of vegetable oil as an alternative substitute for biodiesel was investigated. The used vegetable oil (UVO) was obtained from Baraka Factory – Potato chips line, Wad Madani, Sudan. The biodiesel is produced from used vegetable oil by alkali transesterification. The kinematic viscosity of biodiesel (at 40ºC), flash point, density (at 15ºC), and calorific value were 5.35cSt, 119ºC, 0.881gm/ml, and 41.9MJ/kg respectively. The results showed that the used vegetable oil is suitable for biodiesel productio

Information-theoretic methods for studying population codes

Population coding is the quantitative study of which algorithms or representations are used by the brain to combine together and evaluate the messages carried by different neurons. Here, we review an information-theoretic approach to population coding. We first discuss how to compute the information carried by simultaneously recorded neural populations, and in particular how to reduce the limited sampling bias which affects the calculation of information from a limited amount of experimental data. We then discuss how to quantify the contribution of individual members of the population, or the interaction between them, to the overall information encoded by the considered group of neurons. We focus in particular on evaluating what is the contribution of interactions up to any given order to the total information. We illustrate this formalism with applications to simulated data with realistic neuronal statistics and to real simultaneous recordings of multiple spike trains.Instituto de Física La PlataInstituto de Investigaciones Fisicoquímicas Teóricas y Aplicada

Design and Optimization of Coupled Microring Resonators (MRRs) in Silicon-on-Insulator

The design of microring resonators (MRRs) for serial configuration, integrated in the lateral scheme was presented and simulated using 3D electromagnetic simulator based on finite integration technique. The device model is embedded on the high index contrast (HIC) structure of silicon-on-insulator with monomodal cavity for TE-mode polarizations. From the proposed model, we varied the MRRs order, waveguides separation distance and ring radius, in order to evaluate the influence of those parameters on the device performance in terms of loss, free spectral range (FSR) and quality factor (Q-factor). Upon varying the gap distances, it was found that the highest Q-factor value of the proposed design was 1275 obtained at gap separation of 150 nm for ring radius of 6 μm, while the largest FSR was 24 nm. The trade-offs between device compactness, optical bandwidth and Q-factor are also presented

Characteristics of biomass in flameless combustion: A review

The demands of energy and pollutant emissions reduction have motivated the combustion researchers to work on combustion improvement. Flameless combustion or high temperature air combustion has many features such as flame stability, low pollutant emission and uniform profiles of temperature compared to the other modes of combustion. Combustion of solid fuels likes biomass and wastes in flameless combustion conditions has not been investigated as comprehensive as combustion of gaseous fuels. The aim of using biomass in combustion is to reduce the pollutant emissions and to decrease the rate of fossil fuel consumption. In this review, combustion characteristics of biomass in flameless combustion are explained. The paper summarizes the research on the mass loss, ignition time, and NOx emissions during biomass flameless combustion. These summaries show that biomass under flameless combustion gives low pollutant emissions, low mass loss and it decreases the ignition time. © 2014 Elsevier Ltd

Review of numerical studies on NO\u3csub\u3eX\u3c/sub\u3e emission in the flameless combustion

The incomplete process of combustion produces unwanted emission and one of the major pollutant in the combustion of fossil fuels is the formation of nitrogen oxides. To mitigate the problem various combustion technologies have been explored and flameless combustion is one of the potential candidate. Flameless combustion is of a great interest since it simultaneously provides higher thermal efficiency together with controlling the pollutant emission such as NOX. In this technology, the preheat temperature of the combustion air must be higher than the auto-ignition temperature of the reactant mixture. This paper explores various numerical studies performed on the flameless combustion and the role of flameless combustion on the reduction of NOX emission are presented. © (2013) Trans Tech Publications, Switzerland