A Compact Three-Port DC-DC Converter for Integrated PV-Battery System

© 2018 IEEE. In this paper, a new non-isolated three-port DC-DC converter (NITPC) to integrate a battery storage with a PV module is proposed. The intermittency of renewable energy and the unpredictable load demand are eliminated by firming a backup battery with the PV module to supply extra power when it is required. The proposed converter is reconfigurable and able to operate as a conventional boost converter, a buck-boost converter or a forward converter in different modes to support several power flow combinations and achieve power conditioning and regulation among the PV module, battery and an output port simultaneously. Nevertheless, the converter only consists of two switches, one coupled inductor, one diode and two capacitors. Thus, the system size and number of components are reduced compared with the traditional DC-DC converters. High output regulated voltage is achieved by using a coupled inductor and by combining the PV module and the battery in series. Simulation and experiment are carried out to verify the proposed circuit

Nexus of Strategic Thinking, Knowledge-Oriented Leadership, and Employee Creativity in Higher Education Institutes

Purpose: The aim of this study is to examine strategic thinking and knowledge-oriented leadership influence employees' creativity in the setting of Jordanian private universities.   Theoretical framework: The study employed Path Goal Theory to clarify the interaction of the variables used in Higher Education Institutes to address the issue.   Design/methodology/approach: The research used a “partial least squares-structural equation modeling” approach to examine the gathered data. For analysis purpose, was developed and empirically verified with data (n = 143) obtained from a random sample of private universities in Jordan.   Findings: The result found that Strategic thinking promotes and increases employee creativity. However, knowledge-oriented leadership moderates the causal association between strategic thinking and employee creativity.   Research implications: The results are presented taking into account the relevant research as well as the practical implications for higher education administrators.   Originality/value: The novel theoretical contribution that was made by this study is its emphasis on knowledge-oriented leadership as a moderator in the link between strategic thinking and employee creativity

How Spiritual Leadership Influences Creative Behaviors: the Mediating Role of Workplace Climate

Purpose: The aim of this study is to examine the relationship between spiritual leadership and creative behavior with workplace climate as mediating variable in the Jordanian banking.   Theoretical framework: The purpose of this study, which extends the theories of intrinsic motivation and social exchange, is to acquire a deeper knowledge of the mechanisms underlying the relationship between spiritual leadership and innovative workplace behavior.   Design/methodology/approach: The study used quantitative research approach through a survey based on random sampling method from (n= 358) employees of 13 Jordanian commercial banks in Amman. For purposes of analysis, structural equation modeling was then utilized for the examination of the research hypotheses.   Findings: The results of the research indicated that workplace climate mediates the link between spiritual leadership and creative behavior. Specifically, greater levels of creative behavior among employees were related to spiritual leadership, as was a favorable working environment.   Research, Practical & Social implications: The study offers managerial and theoretical implications while considering the study’s limitations to provide guidance for the future.   Originality/value: The study identifies the magnificent influence of spiritual leadership and the workplace climate by delineating how these factors stimulate creative behaviors among employees. Specifically, the study focuses on how spiritual leadership and the workplace climate stimulate creative behaviors among employees. We examine the consequences of these findings for both research and practice

Simple and Fast Dynamic Photovoltaic Emulator based on a Physical Equivalent PV‐cell Model

Photovoltaic emulators are a specific type of power electronics system to mimic the behaviour of a photovoltaic (PV) panel or array and facilitate the testing of energy systems. Existing solutions usually require sophisticated hardware design and fast computing. This paper presents a simple, reliable, and effective circuit-based photovoltaic (PV) emulator based on the equivalent PV stacked cells. The PV emulator can be used for solar system testing and analysis, such as maximum power point tracking (MPPT) and partial shading effect. The – and – characteristic curves of the emulator have been generated by using an LTspice simulator. It is experimentally investigated and compared with a real PV panel and existing emulator products. The experiment results show good agreement with the mimicked actual PV panel. The proposed PV emulator shows a better dynamic response and shorter settling time than several benchmarked commercial products. The enhancement in the time response is due to the simplicity of the emulator, where a few power diodes and some resisters are used. In addition to simplicity, the PV emulator is very cost-effective

Efficiency Improvement Scheme for PV Emulator Based on a Physical Equivalent PV-Cell Model

Recently, a photovoltaic (PV) emulator is proposed which is based on a combination of a constant current source and a one-diode photovoltaic model. Its superior dynamic performance is compatible with that of a real PV system. Although it is power efficient at the maximum power point (MPP), it suffers from high power loss around and at the open-circuit voltage (OCV) operation condition. The PV emulator can be used for PV system analysis and testing, such as maximum power point tracking (MPPT). This paper presents a new switching circuit which is placed in parallel with the diode string to minimize the power loss. The switching circuit consists of a two-switch non-inverting buck-boost DC/DC converter. When the operating point of the PV emulator moves from the current source region to the voltage source region, the converter, which is more efficient, switches in to replace the diode string seamlessly to maintain the circuit operation of the emulator. Experimental results show that in the worst case scenario, i.e. OCV condition, the efficiency and temperature of the proposed solution reach 81.47% and 30.1 °C respectively, as compared with 2.8% and 94.2 °C respectively for the diode string only case. In terms of dynamic response, the proposed PV emulator lags the real PV panel by only 3.5 ms as compared with 120 ms by a commercial emulator under the 30% to 60% insolation change test

Coronavirus disease 2019 (COVID-19): a brief overview of features and current treatment

Since the report of the first cases of pneumonia caused by SARS-CoV-2 in December 2019, COVID-19 has become a pandemic and is globally overwhelming healthcare systems. The symptoms of COVID-19 vary from asymptomatic infection to severe complicated pneumonia with acute respiratory distress syndrome (ARDS) and multiple organ failure leading to death. The estimated case-fatality rate among infected patients in Wuhan, the city where the first case appeared, was 1.4%, with 5.1 times increase in the death rate among those aged above 59 years than those aged 30–59 years. In the absence of a proven effective and licensed treatment, many agents that showed activity against previous coronavirus outbreaks such as SARS and MERS have been used to treat SARS-CoV-2 infection. The SARS-CoV-2 is reported to be 80% homologous with SARS-CoV, and some enzymes are almost 90% homologous. Antiviral drugs are urgently required to reduce case fatality-rate and hospitalizations to relieve the burden on healthcare systems worldwide. Randomized controlled trials are ongoing to assess the efficacy and safety of several treatment regimens

Review of Virginia Woolf's Night and Day

In this Review article, we have looked at different aspects that make Virginia Woolf's Night and Day one of the most interesting to read and analyze. We particularly focus on the familial and social patterns that distinguish this novel from other ones written by the same author. We also placed a good emphasis on the strength points the novel shows by looking at various elements such as themes of love relationships, modern treatment of plot and content, and more importantly on characterizations. The article revealed that Woolf's Night and Day is rich in terms of its modern and unconventional approach towards characters, plot, style, and thematic content which all make it a successful novel.

Recalling the Past in Postcolonial Drama: From Counter-History to Sociopolitical Redress

Through examining the texts of Ama Ata Aidoo's  play Anowa (1970), Jack Davis's play Kullark (or Home)(1979), and Dennis Scott's play An Echo in the Bone (1974); this paper  shows how postcolonial drama functions as an effective means for exploring occluded pre-colonial and colonial periods through constructing alternative histories that both refract the official accounts of the colonialist history and redress or treat contemporary societal and political exclusions. To this end, the researchers argue that the counter-discursive/ counter-historical task of many historical postcolonial dramas is to reconstruct their histories in a way that confirms the essential socio-political function of such plays. In this sense, a conscious linkage is being made between contemporary post-colonial communities and their past pre-colonial and colonial histories

Violence Patterns in Peckinpah's The Wild Bunch (1969): Critical Reading

This paper focuses on the issue of violence in Sam Peckinpah's The Wild Bunch (1969) through explaining some of the cultural and historical implications of violence in the 1960s such as Vietnam War, the Mexican war and also the explosion of the feminist movement and some other important social and political upheavals that shaped the cultural context of the 1960s in America. It also sheds light on Sam Peckinpah’s approach of violence screen and stylizing violence and the representations of violence as a tormenting and brutalizing reality that matches the spirit of the age in addition to the social, political, and colonial conflicts of the 1960s. Violence and the implications of violence in The Wild Bunch whether social , cultural, psychological, or humanistic have been discussed in brief in order to show the critical approach of the film as being a rich and didactic film to watch, especially in terms of its rich cultural and historical contexts.