Search results for: power factor correction

Authors: Firat Arslan, Hasan Degirmenci, Serife Tulin Akkaya Aslan

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The aim of the current experiment was to determine the relationship among shape indexes which are used by the researchers in many fields to evaluate parcel shapes which is very important for farming even if these indexes are controversial. In the current study, land consolidation project of Halitaga village in Mersin province in Turkey which has 278 parcel and cover 894.4 ha, was taken as a material. Commonly used indicators such as fractal dimension (FD), shape index (SI), form factor (FORM), areal form factor (AFF) and two distinct area-perimeter ratio (APR-1 and APR2) in land consolidation are used to measure agricultural plot’s shape. FD was positively correlated with SI, APR-1 and APR-2 whereas it was negatively correlated with FORM and AFF. SI was positively correlated with APR-1 and APR-2 whereas it was negatively correlated with FORM and AFF. As a conclusion, it is likely that these indexes involved may be used interchangeably due to high correlations among them.

Keywords: GIS, land consolidation, parcel shape, shape index

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Authors: Ugochukwu D. Abasilim, Aize I. Obayan, Adedayo J. Odukoya, Godwyns Agube, Power A. I. Wogu, Nchekwube Excellence-Oluye

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This paper examines the effect of transformational leadership style on organizational commitment among Private University employees in Nigeria. A quantitative methodology was adopted for this study. A structured Multi-factor Leadership Questionnaire (MLQ) developed by Bass and Avolio (1997) and Organizational Commitment Questionnaire (OCQ) developed by Meyer and Allen (1997) were the major instruments used for data collection. Simple linear regression was used for testing the hypothesis. The results indicated that there was no significant positive effect of transformational leadership style on organizational commitment among employees of the Nigerian private university studied. Though the respondents rated their leaders high on transformational leadership style, their organizational commitment rating was average for majority, which implies that employees’ level of commitment could be accounted for by transformational leadership style existing in the institution. This finding is antithetical to the common submission in literature that transformational leadership style has a significant effect on organizational commitment. It was therefore recommended that further studies may want to further explore the reasons for this variance.

Keywords: leadership style, Nigeria, organizational, commitment, transformational leadership

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Authors: Tsuyoshi Yamazaki, Etsuo Morishita

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Cyclists often run through a crosswind and sometimes we experience the adverse pressure. We came to an idea that Wells turbine can be used as power augmentation device in the crosswind something like sails of a yacht. Wells turbine always rotates in the same direction irrespective of the incoming flow direction, and we use it in the small-scale power generation in the ocean where waves create an oscillating flow. We incorporate the turbine to the wheel of a bike. A commercial device integrates strain gauges in the crank of a bike and transmitted force and torque applied to the pedal of the bike as an e-mail to the driver’s mobile phone. We can analyze the unsteady data in a spreadsheet sent from the crank sensor. We run the bike with the crank sensor on the rollers at the exit of a low-speed wind tunnel and analyze the effect of the crosswind to the wheel with a Wells turbine. We also test the aerodynamic characteristics of the turbine separately. Although power gain depends on the flow direction, several Watts increase might be possible by the Wells turbine incorporated to a bike wheel.

Keywords: aerodynamics, Wells turbine, bicycle, wind engineering

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Authors: Paramita Banerjee, K. R. S. Chandrakumar, G. P. Das

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Bulk MgH2 has drawn much attention for the purpose of hydrogen storage because of its high hydrogen storage capacity (~7.7 wt %) as well as low cost and abundant availability. However, its practical usage has been hindered because of its high hydrogen desorption enthalpy (~0.8 eV/H2 molecule), which results in an undesirable desorption temperature of 3000C at 1 bar H2 pressure. To surmount the limitations of bulk MgH2 for the purpose of hydrogen storage, a detailed first-principles density functional theory (DFT) based study on the structure and stability of neutral (Mgm) and positively charged (Mgm+) Mg nanoclusters of different sizes (m = 2, 4, 8 and 12), as well as their interaction with molecular hydrogen (H2), is reported here. It has been found that due to the absence of d-electrons within the Mg atoms, hydrogen remained in molecular form even after its interaction with neutral and charged Mg nanoclusters. Interestingly, the H2 molecules do not enter into the interstitial positions of the nanoclusters. Rather, they remain on the surface by ornamenting these nanoclusters and forming new structures with a gravimetric density higher than 15 wt %. Our observation is that the inclusion of Grimme’s DFT-D3 dispersion correction in this weakly interacting system has a significant effect on binding of the H2 molecules with these nanoclusters. The dispersion corrected interaction energy (IE) values (0.1-0.14 eV/H2 molecule) fall in the right energy window, that is ideal for hydrogen storage. These IE values are further verified by using high-level coupled-cluster calculations with non-iterative triples corrections i.e. CCSD(T), (which has been considered to be a highly accurate quantum chemical method) and thereby confirming the accuracy of our ‘dispersion correction’ incorporated DFT calculations. The significance of the polarization and dispersion energy in binding of the H2 molecules are confirmed by performing energy decomposition analysis (EDA). A total of 16, 24, 32 and 36 H2 molecules can be attached to the neutral and charged nanoclusters of size m = 2, 4, 8 and 12 respectively. Ab-initio molecular dynamics (AIMD) simulation shows that the outermost H2 molecules are desorbed at a rather low temperature viz. 150 K (-1230C) which is expected. However, complete dehydrogenation of these nanoclusters occur at around 1000C. Most importantly, the host nanoclusters remain stable up to ~500 K (2270C). All these results on the adsorption and desorption of molecular hydrogen with neutral and charged Mg nanocluster systems indicate towards the possibility of reducing the dehydrogenation temperature of bulk MgH2 by designing new Mg-based nano materials which will be able to adsorb molecular hydrogen via this weak Mg-H2 interaction, rather than the strong Mg-H bonding. Notwithstanding the fact that in practical applications, these interactions will be further complicated by the effect of substrates as well as interactions with other clusters, the present study has implications on our fundamental understanding to this problem.

Keywords: density functional theory, DFT, hydrogen storage, molecular dynamics, molecular hydrogen adsorption, nanoclusters, physisorption

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Authors: A. Oukaira, A. Lakhssassi, O. Ettahri

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To make a good thermal management in an ABDM (Adapter Board Detector Module) card, we must first control temperature and its gradient from the first step in the design of integrated circuits ASIC of our complex system. In this paper, our main goal is to develop and validate the thermal stability in order to get an idea of the flow of heat around the ASIC in transient and thus address the thermal issues for integrated circuits at the ABDM card. However, we need heat sources simulations for ABDM card to establish its thermal mapping. This led us to perform simulations at each ASIC that will allow us to understand the thermal ABDM map and find real solutions for each one of our complex system that contains 36 ABDM map, taking into account the different layers around ASIC. To do a transient simulation under NISA, we had to build a function of power modulation in time TIMEAMP. The maximum power generated in the ASIC is 0.6 W. We divided the power uniformly in the volume of the ASIC. This power was applied for 5 seconds to visualize the evolution and distribution of heat around the ASIC. The DBC (Dirichlet Boundary conditions) method was applied around the ABDM at 25°C and just after these simulations in NISA tool we will validate them by COMSOL tool, wich is a numerical calculation software for a modular finite element for modeling a wide variety of physical phenomena characterizing a real problem. It will also be a design tool with its ability to handle 3D geometries for complex systems.

Keywords: ABDM, APD, thermal mapping, complex system

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Authors: Irna Farikhah

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Converting low-grade waste heat into useful energy such as sound energy which can then be used to generate acoustic power in a thermoacoustic engine has become an attracting issue for researchers. The generated power in thermoacoustic engine can be used for driving a thermoacoustic cooler when they are installed in a tube. This cooler system can be called as a heat-driven thermoacoustic cooler. In this study, low heating temperature of the engine is discussed. In addition, having high efficiency of the whole cooler is also essential. To design a thermoacoustic cooler having high efficiency with using low-grade waste heat for the engine, the effect of mean pressure is investigated. By increasing the mean pressure, the heating temperature to generate acoustic power can be decreased from 557 °C to 300 °C. Moreover, the efficiency of the engine and cooler regenerators attain 67% and 47% of the upper limit values, respectively and 49% of the acoustical work generated by the engine regenerator is utilized in the cooler regenerator. As a result, the efficiency of the whole cooler becomes 15% of the upper limit value.

Keywords: cooler, mean pressure, performance, thermoacoustic

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Authors: Sajjad Shalsouz, Hamid karamipour

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Islamic civilization after a period of glory in the ninth and tenth centuries AD, known as the Islamic Renaissance, stagnated and declined from the eleventh century, despite the political and military power of Islamic governments, faced a scientific and cultural decline in later, foreign invaders such as the Mongol invasion, the Crusades, and Timur invasions also caused severe political, social, and economic instability, some of which were never remedied. Lack of growth of intellectual sciences in Islamic societies, which is necessary for the growth and development of any civilization, and lack of attention of the ruling class and the masses to this important factor, the tyranny of kings, social and economic turmoil from the thirteenth century onwards, absence of Islamic societies from global developments all intensified and stabilized the decline Islamic civilizations, the consequences of which are still evident. This article tries to deal with the historical factors of this decline and decadence from the 11th century to the contemporary era by examining historical events and issues and achieves a desirable and efficient result in this field.

Keywords: Islamic civilization, decline, historical factors, intellectual sciences

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Authors: Sid Ahmed Ziane

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This paper argues for Johnson's financial responsiveness to the rise of Black Power and its advocate, 'Stokely Carmichael' in 1966. John H. Johnson was a Black businessman and the owner of Ebony magazine, one of the widely read Black magazines in the U.S. His magazine, however, was designed only to promoting Black fashion, aesthetic, marketing, and consumerism. In mid-1966, the mainstream of the Civil Rights movement was heading into two distinct camps when some of its advocates, led by Stokely Carmichael, began to question the slow pace of the Civil Rights and sought to pursue a more radical approach to bring about upheaval to the Black community. Their new approach, however, propelled the national media into paying close attention to their activities, their new methods, and their radical orientations. In fact, the major White-oriented media discredited Carmichael and distorted his public image via sensational stories and race-mongering reports. However, the Black owned outlets such as The Liberator advocated his agendas, whereas other magazines such as The Crisis rejected them. Based on such oral sources and Ebony’s online issues, this paper adds and argues that Johnson had also responded to the rise of Black Power and Carmichael. This reaction had, in fact, aimed at scooping and selling Carmichael and his new orientation as well as advertising him in his magazine to attract the readers who showed a strong tendency to hear and read about the heyday and even the ferment of Black Power. This paper is part of an ongoing project which aims at framing our understanding of how the Black print media and the modern Black liberation struggle were correlated and could shape each other by appraising their agendas, milestones, and their pivotal figures.

Keywords: Black power, Ebony magazine, John Johson, Stokely Carmichael

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Authors: Andressa dos Santos Nicolau, João P. da S.C Algusto, Claudio Márcio do N. A. Pereira, Roberto Schirru

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In case of abnormal situations, the nuclear power plant (NPP) operators must follow written procedures to check the condition of the plant and to classify the type of emergency. In this paper, we proposed a Real Time Expert System in order to improve operator’s performance in case of transient or accident with reactor shutdown. The expert system’s knowledge is based on the sequence of events (SoE) of known accident and two emergency procedures of the Brazilian Pressurized Water Reactor (PWR) NPP and uses two kinds of knowledge representation: rule and logic trees. The results show that the system was able to classify the response of the automatic protection systems, as well as to evaluate the conditions of the plant, diagnosing the type of occurrence, recovery procedure to be followed, indicating the shutdown root cause, and classifying the emergency level.

Keywords: emergence procedure, expert system, operator support, PWR nuclear power plant

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Authors: Yun-Ru Tsai, Jo-Hui Lin

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The cultural interactions between tourists and destination communities have received increased attention. Tourists play an important role in constructing a rewarding intercultural experience and cultural understanding. Cultural literacy is the ability for tourists to negotiate different cultures, this research aimed to develop a measurement of Tourist Cultural Literacy (TCL), the result provides a theoretical framework to assess how tourists interact with different cultural destinations. A pilot qualitative research was conducted in order to generate the initial items. In this study, the procedure of developing the TCL scale was divided into two parts. First, an exploratory factor analysis was conducted, a 25-item TCL scale was developed and six factors were identified: cultural sensitivity, appreciation of the culture, respect for the culture, knowledge of the culture, participate in the culture, and empathy for the culture. Second, confirmatory factor analyses and structural equation modeling were employed, the six-factor model was verified, and was proven to have good fit, reliability, convergent validity, discriminant validity, and criterion-related validity. The study provides managerial implications for tourist management and education, the popularization of TCL might increase the respect and understanding between tourists and local societies as well as decrease the cultural shocks and negative social-cultural impacts derived from tourism activities, thereby reducing the maintenance cost of management and allowing tourists to obtain a better cultural experience. Future research suggestions are also provided.

Keywords: cultural literacy, cultural tourism, scale development, tourism contact

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Authors: Rafayel K. Kostanyan

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The opportunities of use of metallic magnesium as a generator of hydrogen gas, as well as thermal and electric energy is presented in the paper. Various schemes of magnesium application are discussed and power characteristics of corresponding devices are presented. Economic estimation of hydrogen price obtained by different methods is made, including the use of magnesium as a source of hydrogen for transportation in comparison with gasoline. Details and prospects of our new inexpensive technology of magnesium production from magnesium hydroxide and magnesium bearing rocks (which are available worldwide and in Armenia) are analyzed. It is estimated the threshold cost of Mg production at which application of this metal in power engineering is economically justified.

Keywords: energy, electrodialysis, magnesium, new technology

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Authors: Mesbah Tarek, Kelaiaia Samia, Chiheb Sofien, Kelaiaia Mounia Samira, Labar Hocine

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Short circuit causes important damage in power systems. The aim of this paper is the investigation of the effect of short circuit at the AC side inverter in HVDC transmission line. The cutoff of HVDC transmission line implies important economic losses. In this paper it is proposed an efficient procedure which can protect and eliminate the fault quickly. The theoretical development and simulation are well detailed and illustrated.

Keywords: AC inverter, HVDC, short circuit, switcher gate, power system

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Authors: S. Ghafoori, A. Al-Harbi, B. Al-Ajmi, A. Al-Shaalan, A. Al-Ajmi, M. Ali Juma

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Seismic methods play an important role in the exploration for hydrocarbon reservoirs. However, the success of the method depends strongly on the reliability of the measured or predicted information regarding the velocity of sound in the media. Speed of sound has been used to study the thermodynamic properties of fluids. In this study, experimental data are reported and analyzed on the speed of sound in toluene and octane binary mixture. Three-factor three-level Box-Benhkam design is used to determine the significance of each factor, the synergetic effects of the factors, and the most significant factors on speed of sound. The developed mathematical model and statistical analysis provided a critical analysis of the simultaneous interactive effects of the independent variables indicating that the developed quadratic models were highly accurate and predictive.

Keywords: experimental design, octane, speed of sound, toluene

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Authors: Michal Bialy, Marcin Szlachetka, Mateusz Paszko

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This paper discusses the CFD results of heat transfer in water channels in the engine body. The research engine was a newly designed Diesel combustion engine. The engine has three cylinders with three pairs of opposed pistons inside. The engine will be able to generate 100 kW mechanical power at a crankshaft speed of 3,800-4,000 rpm. The water channels are in the engine body along the axis of the three cylinders. These channels are around the three combustion chambers. The water channels transfer combustion heat that occurs the cylinders to the external radiator. This CFD research was based on the ANSYS Fluent software and aimed to optimize the geometry of the water channels. These channels should have a maximum flow of heat from the combustion chamber or the external radiator. Based on the parallel simulation research, the boundary and initial conditions enabled us to specify average values of key parameters for our numerical analysis. Our simulation used the average momentum equations and turbulence model k-epsilon double equation. There was also used a real k-epsilon model with a function of a standard wall. The turbulence intensity factor was 10%. The working fluid mass flow rate was calculated for a single typical value, specified in line with the research into the flow rate of automotive engine cooling pumps used in engines of similar power. The research uses a series of geometric models which differ, for instance, in the shape of the cross-section of the channel along the axis of the cylinder. The results are presented as colourful distribution maps of temperature, speed fields and heat flow through the cylinder walls. Due to limitations of space, our paper presents the results on the most representative geometric model only. Acknowledgement: This work has been realized in the cooperation with The Construction Office of WSK ‘PZL-KALISZ’ S.A. and is part of Grant Agreement No. POIR.01.02.00-00-0002/15 financed by the Polish National Centre for Research and Development.

Keywords: Ansys fluent, combustion engine, computational fluid dynamics CFD, cooling system

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Authors: Zhang Zhenzhen

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Valproate (VPA) is commonly used in the treatment of bipolar disorder and epilepsy. The mechanism is complicated, including its ability to inhibit histone deacetylases (HDACs). Here, we show that VPA attenuated VEGF gene expression and the morphological changes in choroidal neovascularization (CNV) induced by photocoagulation in retina. C57BL/6 mice were injected subcutaneously at 300mg/kg twice daily with VPA before insult. Vascular endothelial growth factor (VEGF)-A and VEGF-B were examined in the eyes of VPA-treated mice and in human retinal pigment epithelial cell lines (ARPE-19) exposed to VPA. In addition, CNV was induced by photocoagulation in mice injected with VPA, and the volume of CNV was compared by fluorescence-labeled choroidal flat mount. Morphological changes were analyzed on stained histological sections. Western blot analysis was used to determine protein levels of VEGF-A and VEGF-B, and acetylation of histone H3 in each group. VPA injected intraperitoneally attenuated the VEGF-A and VEGF-B expression in the retina, accompanied by the hyperacetylation of retina tissue, indicating that VPA acts directly on retina tissues through acetylation to reduce the expression of VEGF. VPA also attenuated the VEGF-A mRNA expression in the retinal pigment epithelium showed by immunohistochemistry. Moreover, the administration of VPA significantly attenuated photocoagulation-induced CNV in mice. These results demonstrate that VPA attenuated VEGF production in retina associated with choroidal neovascularization possibly via the HDAC inhibition.

Keywords: retina, acetylation, chorodial neovascularization, vascular endothelial growth factor

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Authors: H. Demirtaş, İ. H. Kara, H. Ahlatcı

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Welding failures of steel pipes in power plants usually occur in weld zones. This is similar for the economizer, water walls and superheaters in the power plants where SA 210 Gr. C steel pipes are used. Although these steel pipes have very good welding properties, the welding parameters are also important for the welding life. Welding processes of this pipes are carried out by TIG and SMA techniques. In this study SA 210 Gr. C steel pipes were welded by TIG method and investigated how PWHT affected the welding properties. The results show that this steel does not require post weld heat treatment.

Keywords: SA 210 Gr. C steel pipes, TIG welding, HAZ region, Widmanstatten ferrite

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Authors: Takhchi Jamal, Ouisse Morvan, Sadoulet-Reboul Emeline, Bouhaddi Noureddine, Gagliardini Laurent, Bornet Frederic, Lakrad Faouzi

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Structural intensity is a technique that can be used to indicate both the magnitude and direction of power flow through a structure from the excitation source to the dissipation sink. However, current analysis is limited to the low frequency range. At medium and high frequencies, a rotational component appear in the field, masking the energy flow and make its understanding difficult or impossible. The objective of this work is to implement a methodology to filter out the rotational components of the structural intensity field in order to fully understand the energy flow in complex structures. The approach is based on the Helmholtz decomposition. It allows to decompose the structural intensity field into rotational, irrotational, and harmonic components. Only the irrotational component is needed to describe the net power flow from a source to a dissipative zone in the structure. The methodology has been applied on academic structures, and it allows a good analysis of the energy transfer paths.

Keywords: structural intensity, power flow, helmholt decomposition, irrotational intensity

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Authors: Berna Eren Tokgoz, Mahdi Safa, Seokyon Hwang

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Power distribution systems are essential and crucial infrastructures for the development and maintenance of a sustainable society. These systems are extremely vulnerable to various types of natural and man-made disasters. The assessment of resilience focuses on preparedness and mitigation actions under pre-disaster conditions. It also concentrates on response and recovery actions under post-disaster situations. The aim of this study is to present a methodology to assess the resilience of electric power distribution poles against wind-related events. The proposed methodology can improve the accuracy and rapidity of the evaluation of the conditions and the assessment of the resilience of poles. The methodology provides a metric for the evaluation of the resilience of poles under pre-disaster and post-disaster conditions. The metric was developed using mathematical expressions for physical forces that involve various variables, such as physical dimensions of the pole, the inclination of the pole, and wind speed. A three-dimensional imaging technology (photogrammetry) was used to determine the inclination of poles. Based on expert opinion, the proposed metric was used to define zones to visualize resilience. Visual representation of resilience is helpful for decision makers to prioritize their resources before and after experiencing a wind-related disaster. Multiple electric poles in the City of Beaumont, TX were used in a case study to evaluate the proposed methodology.  

Keywords: photogrammetry, power distribution systems, resilience metric, system resilience, wind-related disasters

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Authors: Jeonghwan Jeon

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Recently, the industry and academia have been planning development through industry/university cooperation (IUC), and the government has been promoting alternative methods to achieve successful IUC. Representatively, business cultivation involves the lead university (regarding IUC), research and development (R&D), company support, professional manpower cultivation, and marketing, etc., and the scale of support expands every year. Research is performed by many academic researchers to achieve IUC and although satisfaction of their results is high, expectations are not being met and study of the main factor is insufficient. Therefore, this research improves on theirs by analysing the main factors influencing their satisfaction. Each factor is analysed by AHP, and portfolio analysis is performed on the importance and current satisfaction level. This will help improve satisfaction of business participants and ensure effective IUC in the future.

Keywords: industry/university cooperation, satisfaction, portfolio analysis, research and development

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Authors: Assile Abou Diab, Shadi Najjar

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Fiber-reinforcement is an effective soil improvement technique for applications involving the prevention of shallow failures on the slope face and the repair of existing slope failures. A typical application is the stabilization of cohesionless infinite slopes. The objective of this paper is to present a probabilistic, reliability-based methodology (based on Monte Carlo simulations) for the design of a practical fiber-reinforced cohesionless infinite slope, taking into consideration the impact of various sources of uncertainty. Recommendations are made regarding the required factors of safety that need to be used to achieve a given target reliability level. These factors of safety could differ from the traditional deterministic factor of safety.

Keywords: factor of safety, fiber reinforcement, infinite slope, reliability-based design, uncertainty

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Authors: Shazia Ali, Yves Mard, Éric Severin

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To the best of our knowledge, this is the first study to have analyzed the impact of a) firm-specific product-market power and b) industry competition on earnings management behavior of European firms in distress versus healthy years while controlling for firm-level characteristics. We predicted a significant relationship between firms’ product market power and earnings management tools and their trade-off under the moderation effect of financial distress. We found that the firm-level market power hereinafter referred to as MP (proxied by the industry-adjusted Lerner Index) is positively associated with both real and accrual earnings management. However, MP is associated with a higher level of real earnings management compared to accrual earnings management in distress years compared to healthy years. On the other hand, industry product market power (representing low competition and proxied by the inverse of the total number of firms in an industry hereinafter referred to as NUMB) and firms product market power (proxied by firm market share hereinafter referred to as MS) are associated with lower inflationary accruals and higher deflationary accruals respectively. On the other hand, they are found to be linked with higher real earnings management in distress versus healthy years. When we divided the sample into small and big firms based on their respective industry-year median total assets, we found that all three measures of industry competition (Industry Median Lerner Index (hereinafter referred to as IMLI), NUMB, and Herfindahl–Hirschman Index (hereinafter referred to as HHI) indicate that small firms in low-competitive industries in financial distress are more likely to inflate their earnings through discretionary accruals. While big firms in this situation are more likely to lower the use of both inflationary and deflationary discretionary accruals as indicated by IMLI and HHI and trade-off accruals earnings management for real earnings management as indicated by NUMB. Moreover, IMLI and HHI did not show any interesting results when we divided the sample based on the firm Lerner Index/Market Power. However, the distressed firms with high market power (MP>industry median) are found to engage in income-decreasing discretionary accruals in low-competitive industries (high NUMB). Whereas firms with low market power in the same industry use downward discretionary accruals but inflate income using real activities (abnCFO). Our findings are robust across alternate measures of discretionary accruals and financial distress, such as the Altman Z-Score. The finding of the study is valuable for accounting standard setters, competition authorities, policymakers, and investors alike to help in informed decision-making.

Keywords: financial distress, earnings management, market competition

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Authors: John Gaber, Youssef Ahmed, Hossam A.Gabbar, Jing Ren

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Nuclear Power Plant (NPP) operators have a large responsibility on their shoulders. They must allow the plant to generate a high amount of energy while inspecting and maintaining the safety of the plant. This type of occupation comes with high amounts of mental fatigue, and a small mistake can have grave consequences. Electroencephalography (EEG) is a method of gathering the electromagnetic waves emitted by a human brain. We propose a safety system by monitoring brainwaves for signs of mental fatigue. This requires an analysis of the tasks and mental models of the NPP operator, as well as risk factors on mental fatigue and attention that NPP operators face when performing their tasks. The brain waves generated from experiencing mental fatigue can then be monitored for. These factors are analyzed, developing an EEG-based monitoring system, which aims to alert NPP operators when levels of mental fatigue and attention start affecting their performance in task completion.

Keywords: EEG, power plant operator, psychology, task analysis

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Authors: Hany M. Fayed, Rehab F. Abdel-Rahman, Alyaa F. Hessin, Hanan A. Ogaly, Gihan F. Asaad, Abeer A. A. Salama, Sahar Abdelrahman, Mahmoud S. Arbid, Marwan Abd Elbaset Mohamed

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Liver fibrosis is a serious global health problem that occurs as a result of a variety of chronic liver disorders. Apigenin, a flavonoid found in many plants, has several pharmacological properties. The aim of this study was to evaluate the antifibrotic efficacy of apigenin (APG) against experimentally induced hepatic fibrosis in rats via using thioacetamide (TAA) and to explore the possible underlying mechanisms. TAA (100 mg/kg, i.p.) was given three times each week for two weeks to induce liver fibrosis. After TAA injections, APG was given orally (5 and 10 mg/kg) daily for two weeks. Biochemical, molecular, histological and immunohistochemical analyses were performed on blood and liver tissue samples. The functioning of the liver, oxidative stress, inflammation, and liver fibrosis indicators were all evaluated. The findings showed that TAA markedly increased the activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT), as well as the levels of malondialdehyde (MDA), focal adhesion kinase (FAK), hypoxia-inducible factor-1 (HIF-1), nuclear factor-κB (NF-κB), transforming growth factor-beta (TGF-β), tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β) with a reduction in albumin, total protein, A/G ratio, GSH content and interleukin-10 (IL-10). Moreover, TAA elevated the content of collagen I, α -smooth muscle actin (α-SMA), and hydroxyproline in the liver. The treatment with APG in a dose-dependent manner has obviously prevented these alterations and amended the harmful effects induced by TAA. The histopathological and immunohistochemical observations supported this biochemical evidence. The higher dose of APG produced the most significant antifibrotic effect. As a result of these data, APG appears to be a promising antifibrotic drug and could be used as a new herbal medication or dietary supplement in the future for the treatment of liver fibrosis. This effect might be related to the inhibition of the HIF-1/FAK signaling pathway.

Keywords: apigenin, FAK, HIF-1, liver fibrosis, rat, thioacetamide

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Authors: Benjamin Lee Warren

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Many problems exist in additive number theory which is essential to determine the primes that are the sum of two elements from a given single-variable polynomial sequence, and most of them are unattackable in the present day. Here, we determine solutions for this problem to a few certain sequences (certain binomial coefficients and power sums) using only elementary algebra and some algebraic factoring methods (as well as Euclid’s Lemma and Faulhaber’s Formula). In particular, we show that there are finitely many primes as sums of two of these types of elements. Several cases are fully illustrated, and bounds are presented for the cases not fully illustrated.

Keywords: binomial coefficients, power sums, primes, algebra

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Authors: Misho Matsankov, Stoyan Petrov

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The paper presents the methodology and the obtained mathematical models for determining the value of the grounding resistance of a disconnected conductor in a three-phase power line, for which the contact voltage is safe, by taking into account the potentials, induced by the non-disconnected phase conductors. The mathematical models have been obtained by implementing the experimental design techniques.

Keywords: contact voltage, experimental design, induced voltage, safety

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Authors: Kriti Upadhyay, Ashraf Ali, Puja Sohal, Randeep Guleria

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Background: In Chronic Obstructive Pulmonary diseases (COPD) pathogenesis oxidative stress plays an important role. Hypoxia-Inducible factor (HIF-1α) is a dimeric protein complex which Functions as a master transcriptional regulator of the adaptive response to hypoxiaand is a risk factor that increases when oxidative stress triggers. The role ofHIF-1αin COPD due to smoking is lacking. Aim: This study aims to evaluate the role of HIF-1α in smoker COPD patients comparing its association with diseases severity. Method: In this cross-sectional study, we recruited 87 subjects, 57 were smokers with COPD,15 were smokers without COPD and other 15 were non-smoker healthy controls. The mean age was 54.6± 9.32 (cases 57.08±8.15; controls 50.0± 9.8). There were 62%smokers, 25% non-smokers,7% tobacco chewers and 6% ex-smokers. Enzyme-linked immune sorbent assay (ELISA) method was used for analyzing serum samples wherein HIF-1α was analyzed by Sandwich-ELISA. Results: In smoker COPD patients, a significantly higher HIF-1α level showed positive association with hypoxia, smoking status and severity of disease (p=0.03). The mean value of HIF-1α was not significantly different in smokers without COPD and healthy controls. Conclusion: It is found that HIF-1α level was increased in smoker COPD, but not in smokers without COPD. This suggests that development of COPD drive the HIF-1α pathway and it correlates with the severity of diseases.

Keywords: COPD, chronic obstructive pulmonary diseases, smokers, nonsmokers, hypoxia

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Authors: Seok Woo Chang, Kee Yeon Kum, Kwang Shik Bae, WooCheol Lee

Abstract:

Aim: The objective of this study was to compare the biocompatibilities and mineralization potential of ProRoot MTA and newly developed calcium phosphate based cement, Capseal. Materials and Methods: The biocompatibilities and mineralization-related gene expressions (Bone sialoprotein (BSP) and osteocalcin (OCN)) of ProRoot MTA and Capseal were also compared by a methylthiazol tetrazolium (MTT) assay and reverse transcription-polymerization chain reaction (RT-PCR) analysis on 1, 3, and 7 days, respectively. Empty rings were used as control group. The results were statistically analyzed by Kruskal-Wallis test with a Bonferroni correction. P-value of < 0.05 was considered significant. Results: The biocompatibilities of ProRoot MTA and Capseal were equally favorable. ProRoot MTA and Capseal affected the messenger RNA expression of osteocalcin and osteonectin. Conclusions: Based on the results, both ProRoot MTA and Capseal could be a useful biomaterial in clinical endodontics.

Keywords: biocompatibility, calcium silicate cement, MTT, RT-PCR

Procedia PDF Downloads 380

Authors: Ryotaro Ishikawa

Abstract:

Social Anxiety Disorder (SAD) is marked by the persistent fear of social or performance situations in which embarrassment may occur. In contrast, SA in Japan and in China is understood differently. Taijin Kyofusho (TKS) is a culture-bound subtype of SAD which has been the focus of recent research. TKS refers to a unique form of SAD found in Japanese and East Asian cultures characterized by a fear of offending others, in contrast to prototypical SAD in which the source of fear is typically concerned about one’s own embarrassment, humiliation, or rejection by others. Criteria for TKS partially overlap with but are distinct from SAD; a primary factor distinguishing TKS from SAD appears to be individualistic versus interdependent or collectivistic self-construals. The aim of this study was to develop a scale to assess the typical SAD and offensive type of SAD (TKS). This study aimed to test the internal consistency and validity of the scale (Dimensional Social Anxiety Scale: DSAS) using university students sample. For this, 148 university students were enrolled (male=90, female=58, age=19.77, Standard Deviation=1.04). As a result of confirmatory factor analysis, three-factor models of DSAS were verified (χ2(74) =128.36). These three factors were named ‘general’, ‘perfomance’, and ‘offensive’. DSAS were significantly correlated with the Liebowitz Social Anxiety Scale (r = .538, p < .001). Good internal consistencies were indicated on the three subscales (α = .76 to 89). In conclusion, this study indicated DSAS has adequate internal consistency and validity for assessing of multi-type of SADs.

Keywords: social anxiety, cognitive theory, assessment, anxiety disorder

Procedia PDF Downloads 103

Authors: Ying Han, Weirong Chen, Qi Li

Abstract:

An energy management method based on equivalent hydrogen consumption minimum strategy is proposed in this paper aiming at the direct-current (DC) microgrid consisting of photovoltaic cells, fuel cells, energy storage devices, converters and DC loads. The rational allocation of fuel cells and battery devices is achieved by adopting equivalent minimum hydrogen consumption strategy with the full use of power generated by photovoltaic cells. Considering the balance of the battery’s state of charge (SOC), the optimal power of the battery under different SOC conditions is obtained and the reference output power of the fuel cell is calculated. And then a droop control method based on time-varying droop coefficient is proposed to realize the automatic charge and discharge control of the battery, balance the system power and maintain the bus voltage. The proposed control strategy is verified by RT-LAB hardware-in-the-loop simulation platform. The simulation results show that the designed control algorithm can realize the rational allocation of DC micro-grid energy and improve the stability of system.

Keywords: DC microgrid, equivalent minimum hydrogen consumption strategy, energy management, time-varying droop coefficient, droop control

Procedia PDF Downloads 291

Authors: Moon Byung Woo, Seok Chang-Sung, Koo Jae-Mean, Kim Sang-Young, Choi Jae Gu, Huh Nam-Su

Abstract:

Recently, the occurrence of the earthquake has increased sharply and many of the casualties have occurred worldwide, due to the influence of earthquakes. Especially, the Fukushima nuclear power plant accident which was caused by the earthquake in 2011 has significantly increased the fear of people and the demand for the safety of the nuclear power plant. Thus, in order to prevent the earthquake accident at nuclear power plant, it is important to evaluate the fracture toughness considering the seismic loading rate. To obtain fracture toughness for the safety evaluation of nuclear power plant, it is desirable to perform experiments with a real scale pipe which is expensive and hard to perform. Therefore, many researchers have proposed various test specimens to replicate the fracture toughness of a real scale pipe. Since such specimens have several problems, the equivalent stress gradient (ESG) specimen has been recently suggested. In this study, in order to consider the effects of the dynamic loading speed on fracture toughness, the experiment was conducted by applying five different kinds of test speeds using an ESG specimen. In addition, after we performed the fracture toughness test under dynamic loading with different speeds using an ESG specimen and a standard specimen, we compared them with the test results under static loading.

Keywords: dynamic loading speed, fracture toughness, load-ratio-method, equivalent stress gradient (ESG) specimen

Procedia PDF Downloads 296