1,278 research outputs found
A Matlab/Simulink Model of Self Excited Induction Generator for an Electrical Brake Application
This paper presents a MATLAB/Simulink dynamic model of an induction generator, which makes simulation studies possible for the design of fuzzy logic controllers for the purpose of controlling the retarding torque output of the generator in an electrical brake application, using the fuzzy logic toolbox of MATLAB. Electrical braking has been proposed in the literature as an alternative to the mechanical braking systems with an advantage of providing lower maintenance costs. An induction generator, acting as a brake, converts the kinetic energy of a vehicle to electrical energy, which can be dissipated in a resistor bank or used in a regenerative mode.The Simulink model developed will be used to design and test controllers for an effective control of the output torque of the electrical brake system
Derivation of a mathematical structure for market-based transmission augmentation in oligopoly electricity markets using multilevel programming
In this paper, we derive and evaluate a new mathematical structure for market-based augmentation of the transmission system. The closed-form mathematical structure can capture both the efficiency benefit and competition benefit of the transmission capacity. The Nash solution concept is employed to model the price-quantity game among GenCos. The multiple Nash equilibria of the game are located through a characterisation of the problem in terms of minima of the R function. The worst Nash equilibrium is used in the mechanism of transmission augmentation. The worst Nash equilibrium is defined as the one which maximises the social cost, total generation cost + total value of lost load. Thorough analysis of a simple three-node network is presented to clearly highlight the mechanism of the derived mathematical structure from different perspectives
Economic Transmission Augmentation With Explicit Modeling of the Competition Benefit
This paper derives and evaluates a mathematical structure for identifying economically-efficient transmission augmentations. The mathematical structure is based on the concepts of sequential-move and simultaneous-move games in applied mathematics. The Nash equilibrium solution concept has been reformulated as an optimization problem in the proposed structure. The problem of multiple Nash equilibria is managed by introducing the concept of the worst-case Nash equilibrium. Both the economic concepts of the "efficiency benefit" and "competition benefit" of the transmission capacity are explicitly modeled in the proposed structure. A simple three-bus example system and Garver's example system are employed and modified to suit the purpose of analysis. A thorough economic study of these example systems is presented to highlight the concept and operation of the proposed mathematical structure from different perspectives. The results demonstrate the utility of the proposed structure for measuring the total economic efficiency benefit of additional transmission capacity
Effect of diethyl maleate on toxicity of linalool against two stored product insects in laboratory condition
Essential oil extracted from plants has been widely investigated for pest control properties, with some proving to be toxic in insect pests. In this study, effect of the synergist diethyl maleate (DEM) on toxicity of one monoterpenoids, linalool was studied against two most common stored-product insects such as Callosobruchus maculatus and Rhyzopertha dominica. Diethyl maleate was combined in mass ratios (1:8 and 1:4) with acetone used and applied on C. maculatus and R. dominica adult. Five concentrations of linalool were tested with four replications at 24 and 48 h with 30 adult insect in each replication. After 24 h of exposure, the LC50 values were estimated to be 23.61 and 31.01 μl/l air, and after 48 h, they were 15.07 and 21.84 for each insect, respectively. A combination of inalool with the synergist after 24 h of exposure, the LC50 values was estimated to be 11.93 and 13.07 μl/l air and after 48 h, they were 7.38 and 7.93, respectively for each insect. The synergist is able to block the specific system of enzymes involved in selection of tolerance in susceptible generations. Diethyl maleate is an inhibitor of glutathione S-transferase (GST) activity. These results show that diethyl maleate decrease doses of linalool.Key words: Diethyl maleate, linalool, LC50, synergism, Rhyzopertha dominica, Callosobruchus maculatus
A brief report on the relationship between self-control, video game addiction and academic achievement in normal and ADHD students
Background and aims:
Over the last two decades, research into video game addiction has grown increasingly. The present research aimed to examine the relationship between video game addiction, self-control, and academic achievement of normal and ADHD high school students. Based on previous research it was hypothesized that there would be a relationship between video game addiction, self-control and academic achievement video game addiction, self-control and academic achievement would differ between male and female students, and the relationship between video game addiction, self-control and academic achievement would differ between normal students and ADHD students.
Methods:
The research population comprised first grade high school students of Khomeini-Shahr (a city in the central part of Iran). From this population, a sample group of 339 students participated in the study. The survey included the Game Addiction Scale (Lemmens, Valkenburg & Peter, 2009), the Self-Control Scale (Tangney, Baumeister & Boone, 2004) and the ADHD Diagnostic checklist (Kessler et al., 2007). In addition to questions relating to basic demographic information, students’ Grade Point Average (GPA) for two terms was used for measuring their academic achievement. These hypotheses were examined using a regression analysis.
Results:
Among Iranian students, the relationship between video game addiction, self-control, and academic achievement differed between male and female students. However, the relationship between video game addiction, self-control, academic achievement, and type of student was not statistically significant.
Conclusions:
Although the results cannot demonstrate a causal relationship between video game use, video game addiction, and academic achievement, they suggest that high involvement in playing video games leaves less time for engaging in academic work
Nebular-Phase Spectra of Nearby Type Ia Supernovae
We present late-time spectra of eight Type Ia supernovae (SNe Ia) obtained at
days after peak brightness using the Gemini South and Keck telescopes.
All of the SNe Ia in our sample were nearby, well separated from their host
galaxy's light, and have early-time photometry and spectroscopy from the Las
Cumbres Observatory (LCO). Parameters are derived from the light curves and
spectra such as peak brightness, decline rate, photospheric velocity, and the
widths and velocities of the forbidden nebular emission lines. We discuss the
physical interpretations of these parameters for the individual SNe Ia and the
sample in general, including comparisons to well-observed SNe Ia from the
literature. There are possible correlations between early-time and late-time
spectral features that may indicate an asymmetric explosion, so we discuss our
sample of SNe within the context of models for an offset ignition and/or white
dwarf collisions. A subset of our late-time spectra are uncontaminated by host
emission, and we statistically evaluate our nondetections of H emission
to limit the amount of hydrogen in these systems. Finally, we consider the
late-time evolution of the iron emission lines, finding that not all of our SNe
follow the established trend of a redward migration at days after
maximum brightness.Comment: 20 pages, 8 figures, 9 tables; accepted to MNRA
Delayed Decision-making in Real-time Beatbox Percussion Classification
This is an electronic version of an article published in Journal of New Music Research, 39(3), 203-213, 2010. doi:10.1080/09298215.2010.512979. Journal of New Music Research is available online at: www.tandfonline.com/openurl?genre=article&issn=1744-5027&volume=39&issue=3&spage=20
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