Lead-acid batteries have been used increasingly in recent years in solar power systems, especially in homes and small businesses, due to their cheapness and advanced development in manufacturing them. However, these batteries have low voltages and low capacities, to increase voltage and capacities, they need to be connected in series and parallel. Whether they are connected in series or parallel, their voltages and capacities must be equal otherwise the quality of service will be degraded. The fact that these different voltages are inherent in their manufacturing, but these unbalanced voltages can be controlled. Using a switched capacitor is a method that was used in many methods for balancing voltages, but their responses are slow. To increase the response and control of the balancing process, this research proposes a novel technique that consists of a dynamic capacitor for controlling the unbalanced voltages of series-connected lead-acid batteries. The proposed technique uses a main capacitor and an inductor with two switches their on/off states are controlled through a pulse width modulation. The technique is designed and validated using MATLAB/Simulink and the results for different cases are compared with other techniques such as switched capacitor technique. Results show that the proposed method promised the balancing control in a shorter time and better performance than other techniques which are crucial in the battery’s voltage balancing.
The researcher attempts to examine Barman model in acquiring the historical concepts among fourth-grade students at literary classrooms. To this end, the researcher held the null hypothesis, there is no significant difference between the experimental groups who was taught based on Barman model and the control group that taught based on the traditional method in acquiring the historical concepts on the post-test. To testify the effectiveness of Barman model, the researcher administered a questionnaire included (60) items on bunch of female-students who were selected from al-khamaeal preparatory school in al-hurriyah district in Baghdad. The author utilized different statistical tools to analyze the collected data. &
... Show MoreIt has aimed by this research at presenting new interpretations to diversification phenomenon and its possible effects on firm value. These interpretations are culminated by the disclosure of the distinct role of resource-based view in the study of relationship between diversification strategy and firm value. The study has conducted on a sample consisted of the largest American companies listed in Fortune 500 along with seven years period
(2005-2011). This first local attempt, which has based on panel dat--a analysis for interpreting an expected variance of firm value due to diversification strategy, may helps with a clear vision to solve the contradiction and confusion surrounded the true linkages between t
In this study the faunistic of lady beetles (Coleoptera, Coccinellidae) was studied in Mehriz region (Yazd province) during 2009-2010. The total number of specimens of coccinellid beetles were collected from 6 different localities having altitudes from 1420-2420 m. Altogether 11 species from 8 genera, 3 tribes and 3 subfamilies were collected and identified. External characters plus characteristics male and female genitalia were used in order to diagnose species. Seven species were recorded for the first time from Yazd province (marked*). Many species were predacious, preying on various species of aphids, mites and coccids. Some species were also sent to Dr. Helmut Fursch in Germany for identification or confirmation. T
... Show MoreThe current research aims to identify the level of strategic orientation and its dimensions (vision, mission, goals, and values) in the Iraqi National Security Service (INSS). The researchers followed the descriptive analytical approach as one of the forms of analysis and organized scientific interpretation to describe a specific phenomenon or problem, adopting the form questionnaire being the main source in collecting data and preparing for this. Based on the program of the Statistical Package of Social Sciences (SPSS 26) to analyze the data and come up with the final research results to identify the opinions of the intended sample on the subject of research, and the questionnaire of (20) paragraphs included the search variable, and was
... Show MoreDespite the significant increase in public spending in Iraq, it was not directed toward the important sectors that have an important role in correcting the productive structure. Rather, most of the public expenditure was going to cover the required imports, or to face shocks, whether security or health, and this caused a continuous decrease in the volume of Iraq's exports of goods and services, as the aim of the study was to review the importance of public debt and its impact on the trade balance, as well as to know the economic policies that can contribute to strengthening the trade balance, as the study proved through the (ARDL) model that there is a direct relationship between the domestic debt and the net trade balance, and an invers
... Show MoreFast economical developments in the US. in second half of nineteenth century contained many social results, such as increasing of stealing and killing crimes and expand of Labor strikes, which resulted in violence actions, and presented acceptable reason for emergence specialist security agencies, first of them "Pinkerton Agency". which played important role in all of that, besides that .. its role in American Civil War such as discovering an attempt to kill elected republican president Abraham Lincoln. This research studied all that aspects, focused on period of 1850 - 1899 of agency's history.
This study included the preparation of the mixture aquatic extracts of Peganum harmala seeds and Pericarp of Punica granutum at concentration (10+50) ?(15+55)? (20+60) mgml .To study the influence of the mixture on the percentage of vitality of the protoscolices of E. granulosus In vitro, as the vitality of protoscolices had caused complete death when the using concentration at time 120,90,60 minute respectively. Also study the effect of mixture in white mice with infectious protoscolices In vivo and study the change occurred in the averages of the weights of the liver and spleen and the averages of its distension In vivo in processed group with mixture at concentration (15+55) , (10+50)mgml ,as which was approach to the negative gro
... Show MoreThe aim of the research is to evaluate the response of the researched leaders towards practicing the concept of the lens, which is its dimensions with (stakeholders, resource mobilization, knowledge development, culture management) and the nature of its relationship to tax pioneer performance represented in its dimensions (strategic direction, leadership indicators, growth, renewal and modernization, efficiency, Effectiveness) The questionnaire was approved as a main tool in collecting data and information from the sample members in the General Authority of Taxes, which number (91) Who are on (M. General Manager, Division Director, Deputy Director, Senior Division Director, Deputy Director, Second Division, Division Officer, M. D
... Show MoreThe aim of this research is to identify the role of strategic agility achieving organizational excellence in one of the formations of the Ministry of Municipalities (Dhi Qar Sewage Directorate), as important service organizations that have a key role in serving and developing the society which faced many administrative challenges and issues and as a result of the changes in the environment is continuing and accelerating, so the adoption of modern administrative concepts such as strategic Agility and knowledge of their role in achieving organizational excellence can help them in facing these changes and achieve what they aspire to. In order to achieve research objectives, two main hypotheses have been formulated. The first hypothe
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