bluuebunny/crossref_metadata_2025 huggingface dataset:
BENEFICIAL EFFECTS OF ETHANOLIC LEAF EXTRACT OF CORIANDRUM SATIVUM ON METANIL YELLOW INDUCED ALTERATION INACTIVITY OF CATALASE AND LEVEL OF LIPID PEROXIDATION IN HERCINE CARDIAC TISSUE IN VITRO
Authors: Dome Rabindra Nath , Hazra Sanjib , Ghosh Debosree , Ghosh Suvendu
Published: May 2017

Objective: The primary aim of the study was to find out a suitable effective dose of metanil yellow that can cause alterations of lipid peroxidation and catalase activity in the heart in vitro and to determine the effectiveness of graded doses of Coriandrum sativum as an antioxidant in preventing lipid peroxidative damage to cardiac tissue and back up catalase activity. Methods: Metanil yellow at different doses (10, 25, 35, 50 µl in phosphate buffer) were applied on isolated hircine heart homogenate (10%) in in vitro followed by estimation of lipid peroxidation and catalase activity after completion of the incubation period. Another set of the experiment included incubation of the heart homogenates with graded dilutions of ethanolic leaf extracts of Coriandrum sativum (CsEth) at concentrations of 10, 20, 30, 40 µl in phosphate buffer medium followed by quantification of the same biochemical parameters as above. This was followed by co-administration of the selected effective dose of metanil yellow (35 µl) and ethanolic leaf extract of Coriandrum sativum (30 µl) on heart homogenate to track the variation in lipid peroxidation and catalase activity in heart homogenate in vitro.Results: Metanil yellow significantly lowered catalase activity in isolated cardiac tissue that was reflected in elevated lipid peroxidation assuming free radical induced oxidative injury to cardiac tissue (p<0.01). However ethanolic leaf extract of Cordiandrum sativum buffered such changes (p<0.01) significantly, presuming a protective action against oxidative cardiac damage.Conclusion: It may be concluded that ethanolic leaf extract of Coriandrum sativum is a promising cardioprotective remedy not only in mitigating free radical mediated lipid peroxidative damage to cardiac tissue but also in reinstating normal catalase activity that may be used an unique herbal based remedy for such cardiac ailments in future.
Acreditación de la Licenciatura en Bibliotecología y Estudios de la Información: garantía social de calidad
Authors: Escalona Ríos Lina
Published: May 2017

La evaluación de los planes de estudio se ha dado por mucho tiempo en las diversas instituciones educativas; sin embargo, el proceso de acreditación es una forma de evaluación que, en México, se inicia a partir de la década de los 90, cuando se instaurar
Apreciaciones de trabajadores de la salud sobre la implementación del sistema de seguridad en la utilización de medicamentos
Authors: Restrepo Vásquez Aleyda , Escobar Montoya Julia Inés
Published: May 2017

Introducción: Los errores en la medicación es uno de los eventos adversos más frecuentes en la mayoría de los países de América Latina, lo que ha llevado a promover un sistema  para su identificación y reducción en las instituciones de salud. Objetivo: Determinar las apreciaciones del personal de la salud sobre el grado de implementación del sistema de seguridad del paciente en la utilización de medicamentos. Materiales y métodos: Estudio cuantitativo descriptivo en una población de 73 trabajadores de la salud. Se diseñó una encuesta a partir de dos instrumentos: el cuestionario de autoevaluación de la seguridad del sistema de utilización de los medicamentos en los hospitales y el cuestionario sobre seguridad de los pacientes: versión española del Hospital del Ministerio de Sanidad y Consumo y se contrastaron con los lineamientos de la política de seguridad del paciente para Colombia. Las respuestas se midieron mediante un baremo con cuatro categorías: cumple, cumple medianamente, no cumple y no sabe. Resultados: El porcentaje promedio de personas que manifestaron un total cumplimiento en la aplicación de la política fue de 65,1% en la estandarización, almacenamiento y distribución de los medicamentos, 61,7% en su prescripción y 65,5% en su administración y registro. Conclusiones: Se evidenció que aproximadamente la mitad de los encuestados apreciaban falta de cumplimiento en la implementación del sistema de seguridad del paciente que enmarca los procesos de utilización de medicamentos en todas sus etapas. Lo anterior deja ver que, si bien existe teóricamente un sistema de seguridad en la medicación de los pacientes en las instituciones estudiadas, es necesario que se fortalezcan las acciones gerenciales tendientes a garantizar su aplicación efectiva con todos los actores implicados, siendo la vigilancia permanente de los procesos un pilar fundamental.
Inhibición del crecimiento de Erwinia chrysanthemi a diferentes concentraciones de ácido fólico: posible uso del ácido fólico como agente bacteriostático y fortificante de la papa Solanum tuberosum
Authors: Marcelo Correa Andrea , Ordóñez Vásquez Adriana , Trespalacios Alba Alicia , Suarez Obando Fernando
Published: May 2017

Introducción: Las enterobacterias del genero Erwinia spp producen enfermedades en la papa, un tubérculo de consumo masivo. La regulación de la metilación del DNA puede regular la proliferación de la Erwinia, de tal modo que las concentraciones del ácido fólico, pueden tener un efecto en la capacidad patógena del microorganismo. De otra parte, el ácido fólico previene la aparición de defectos del tubo neural en humanos. Objetivo: Evaluar al ácido fólico como un agente bacteriostático de la Erwinia y que a su vez sea parte de la fortificación de alimentos de consumo masivo como la papa. Materiales y métodos: Se llevó a cabo la caracterización bioquímica de la Erwinia chrysanthemi, se estudió su crecimiento frente a diferentes concentraciones de ácido fólico Resultados: Al aumentar las concentraciones de la vitamina, desde 0,3 µg/L hasta 6,8 µg/L se inhibe el crecimiento bacteriano de la Erwinia chrysanthemi. La vitamina inhibe el crecimiento en cultivo de Erwinia chrysanthemi  y actúa como agente bacteriostático, aspecto de gran relevancia dado que teóricamente, si la papa estuviera fortificada con el micronutriente, este actuaría contra el agente infeccioso y al mismo tiempo contribuiría al consumo adecuado de la vitamina en la población general.
Governance structures in smallholder pig value chains in Uganda: constraints and opportunities for upgrading
Authors: Ouma Emily , Ochieng Justus , Dione Michel , Pezo Danilo
Published: May 2017

This paper analyses governance structures in Uganda’s smallholder pig value chains by applying the New Institutional Economics framework. It utilises cross sectional and qualitative survey data from randomly selected pig value chain actors in 4 districts. A multinomial logit model is applied to assess the determinants of vertical integration among pig traders. The findings indicate that most relationships at the pig production node of the value chain are based on spot market governance structures supported by personal relationships and trust. Live pig traders are mostly vertically integrated. High integration levels of the pig traders are positively influenced by access to market information, value of investments in the value chain, and dedicated asset specificity in terms of backyard slaughter premises. Upgrading opportunities in the value chain in the form of value addition strategies, policy implementation and promotion of business models that link producer organisations to quality inputs and service suppliers through contractual arrangements are identified.
Unionised strikes’ dynamics and economic performance: An exploratory study
Authors: Mzangwa Shadrack Themba
Published: May 2017

Legally, the freedom of association and the formation of trade and worker unions are part of the fundamental human rights bestowed on the citizens in the Constitution of South Africa, as clearly spelt out in Section 23 and 77(1) of the Labour Relations Act (1995) for employees who are not engaged in essential services. Under the Labour Relations Act (1995), trade unions are granted the right to strike in order to seek better conditions of service. However, there is an increasing concern that the rate of industrial actions or unionised strikes are getting out of hand, especially in recent times. Theoretically and empirically, the direct costs of incessant unionised strikes are well known. In this paper, we explored the economic implications of the ever-growing rate of unionised strikes in post-apartheid South Africa. In particular, we assessed its impact on the most important economic variable, namely, real gross domestic product (GDP). We brought to light the sector that is affected most by unionised strikes in the country, the root causes and the implications for policy. Overall our assessment shows that within the space of five years (i.e. from 2009 to 2013), unionised strikes have led to approximately 10,264,775 days lost, and consequently a fall in GDP by 3.2% in 2014 compared to 3.8% in 2013. The sectors heavily affected by unionised strikes are mainly the mining and the manufacturing sectors. Low wages, unhealthy working conditions, and deficiencies in the bargaining system often emerged as the root causes of unionised strikes. The policymaker should pursue effective initiatives seriously to moderate the rate of unionised strikes in South Africa. Institutionalised means of dispute resolution should be embraced and enhanced. These should include but not be limited to ballot requirements, proper regulation of the use of replacement workers, and compulsory arbitration. Policies that spell out employer-employee mandates should be binding such that no party exploits labour contracts to the detriment of the other.
Fair value hierarchy asset valuation. Does it have any predictive power? An international research on the insurance sector
Authors: Tutino Marco , Pompili Marco
Published: May 2017

The objective of the work is to identify any significant relationships between different levels of fair value hierarchy for the valuation of financial assets and two main variables: market capitalization and net income. We considered a sample of 506 insurance companies in two main areas –in the US and in Europe - all listed between 2013 and 2008. Results confirm the hypothesis of correlation between fair value hierarchy adopted in assessing the asset value and market capitalization of the companies, consistently with previous results of Laghi et al. (2012). Moreover, introducing the market-to-book ratio, results show a problem of undervaluation for insurance companies with a relatively larger amount of Level 2 and Level 3 financial assets than Level 1 assets. Nevertheless, results for companies listed in European markets do not provide strong evidence. Moreover, the relationship between different levels of fair value assets and net income is confirmed for the US market but not strongly enough for European companies to consider Level 3 as anti-cyclical instruments for financial reporting. The research results can be useful in helping investors to assess the impact of fair value hierarchy practice on financial reporting of insurance companies. However, a limitation of the analysis is represented by the use of aggregate data for each class of fair value asset, without considering the specific impact related of composition of each category of financial asset evaluated with fair value hierarchy in financial portfolios.
Relationship between ownership structure and financial performance
Authors: Abu Haija Ayman Ahmad , Alrabba Hussein Mohammed
Published: May 2017

A firm’s ownership structure is important in gauging its market value, These structures have major impacts on the financial performance of firms in either positive or negative way as demonstrated in previous studies. This study aims to identify the relationship between ownership structure (i.e. family, foreign, managerial and institutional ownership) and Jordanian companies’ financial performance. In doing so, we used a sample consisted of 114 companies listed in ASE from 2009 to 2015 (seven years). Using multiple regression using to test whether there are relationships between ownership structure and firms’ financial performance.
The results showed a positive relationship among managerial, institutional and family ownership and financial performance, while there is no significant relationship between foreign ownership and firm’s financial performance. Additionally, the result of the current study has documented that the firm size enhances its financial performance, while the leverage has negative relationship to the company’s financial performance. The implication of these findings is important in many ways, i.e. the existence of ownership forms is vital for a company performance, hence, the prospective investors should consider these forms when investing in companies the results show that R2 value is average which opens up possible research areas in the future to explore new explanatory variables to expand the literature on these issues especially in developing countries.
What it Takes for Women to Reach the Corporate Boardrooms in Malaysia
Authors: Ku Ismail Ku Nor Izah , Abd. Rahman Intan Maiza , Mustapa Ifa Rizad , Abdullah Shamsul Nahar
Published: May 2017

This study seeks to understand how and why women were selected as board members, and reasons for women to accept board appointments. We conduct a questionnaire survey on women who sit on the boards of companies in Malaysia. We provide evidence that education, expertise and leadership qualities are necessary for women to reach the boardrooms. Their willingness to contribute to and share their expertise with a company are the main factors for women to accept the appointment as a director. The women feel that gender is not important in becoming a director compared to one’s capability. A majority of them were recommended by the CEO or other board members to become directors. The outcome of this study complements and strengthens the efforts made by the Malaysian government to achieve the 30 percent target. It is also very beneficial to women who aspire to become corporate directors.
Competitiveness of the Ukrainian audit market
Authors: Mynhardt Ronald H , Plastun Alex , Makarenko Inna
Published: May 2017

Ukrainian association with EU forces the implementation of some EU Directives and Regulation acts in Ukrainian audit market. One of the key issues for compliance with the EU principles is the presence of competition in the market. This paper provides new empirical evidence on the concentration in Ukrainian audit market. The use of different methods to measure market competitiveness: (i) traditional measurements of market competition (Hirschman Index, Lerner Index, Comprehensive concentration index, Entropy Index etc.) to examine market concentration; (ii) a multivariate regression analysis with dummy variables and Kruskal-Wallis test to confirm the hypothesis about market heterogeneity; allows to show that Ukrainian audit market has quasi-competitive character and is characterized by a high level of regional market concentration. To stimulate competition some policy implications are proposed in this paper. Among them are: cancellation of restrictive covenants for some market participants, promotion of integrity tendering practices in attracting auditors to perform tasks on the principles of transparency and openness; increasing the effectiveness of the Antimonopoly Committee of Ukraine regulatory activities in audit sphere; development of local audit practice.
Marketing intangible assets and credit ratings, evidence from MENA
Authors: Satt Harit , Tamek Ahmed
Published: May 2017

This paper aims to link the level of intangible incorporeal assets to the level of debt. In my 14 years analysis (from 2002 to 2015), We have designated 600 companies from MENA countries in order to build the model. In order to identify how the excessive amounts of incorporeal resources characterizes the probability of bringing lower cost of debt, We have connected a Probit relapse study. Therefore, it has been proven that the level of incorporeal assets has an important influence on the interest rate. That is, obtaining great amounts of incorporeal assets expands the organization’s odds to have more favorable credit terms and hence lower interest rate. Additional affirmation to the lenders’ rights shields was included through the results, also its effect on the cost of debt.
Heat and mass transfer in 3-D MHD Williamson-Casson fluids flow over a stretching surface with non-uniform heat source/sink
Authors: Raju Chakravarthula , Sandeep Naramgari , Ali Mohamed , Nuhait Abdullah
Published: May 2017

A mathematical model has been proposed for investigating the flow, heat, and mass transfer in Williamson and Casson fluid-flow over a stretching surface. For controlling the temperature and concentration fields we considered the space and temperature dependent heat source/sink and homogeneous-heterogeneous reactions, respectively. Numerical results are carried out for this study by using Runge-Kutta based shooting technique. The effects of governing parameters on the flow, heat and mass transfer are illustrated graphically. Also computed the skin-friction coefficients for axial and transverse directions along with the local Nusselt number. In most of the studies, homogeneous-heterogeneous profiles were reduced into a single concentration equation by assuming equal diffusion coefficients. For the physical relevance, without any assumptions we studied the individual behavior of the homogeneous-heterogeneous profiles. It is found that the rate of heat and mass transfer in Casson fluid is significantly large while equated with the heat and mass transfer rate of Williamson fluid.
Effect of the inlet opening on mixed convection inside a 3-D ventilated cavity
Authors: Doghmi Hicham , Abourida Btissam , Belarche Lahoucin , Sannad Mohamed , Ouzaouit Meriem
Published: May 2017

Mixed convection heat transfer in a 3-D ventilated cavity is studied numerically using finite volume method. The results are presented in terms of streamlines, temperature distribution, velocity fields, and average Nusselt number for different combinations of thermal and geometrical controlling parameters, namely, Reynolds number, Re = 100, Richardson number (0.01 ? Ri ? 10), relative height of the openings (B = h/L = 1/8) and relative width (0.5 ? A = w/L ? 1). The obtained results show that the flow intensity and the heat transfer rate can be significantly improved by an optimal choice of the mentioned parameters.
STAUSBERG, Michael; Steven ENGLER. The Oxford Handbook of the Study of Religion
Authors: Cruz Eduardo Rodrigues da
Published: May 2017

Sem resumo
Da Psicologia do Attachment à visão neurocientífica proposta por Lee A. Kirkpatrick sobre a religiosidade humana
Authors: Valle Edênio
Published: May 2017

Lee A. Kirkpatrick é um dos nomes de maior destaque na Psicologia da Religião na atualidade. Sua importância como pesquisador e teórico se consolidou graças aos seus trabalhos empíricos sobre a Teoria do Apego (Attachment Theory), originalmente proposta por John Bowlby e Mary Ainsworth. Como esses dois pesquisadores, também Kirkpatrick sofreu a influência da Etologia neoevolucionista de Konrad Lorenz e dos acesos debates que se travaram na Psicanálise britânica do pós-guerra a respeito das relações do bebê com sua a mãe na fase em que a sua sobrevivência física e psicológica depende totalmente de quem dele cuida. O mérito principal de Kirkpatrick ao entrar nessa discussão foi o de aplicar com rigor a Teoria do Apego à religiosidade e a outros semelhantes estados anímicos experimentados não só pelo neonato. Em seus trabalhos há dois momentos distintos e complementares. No primeiro deles, o objeto de sua atenção se concentrou mais na relação de apego propriamente dita. Mais tarde, paralelamente ao grande avanço das Bio e Neurociências e da Psicologia Evolucionária, ele passou a dar ênfase aos processos e mecanismos neurofisiológicos e psicológicos que subjazem às reações psicocomportamentais da criança. Essa progressiva e coerente mudança de enfoque fez de Kirkpatrick um renomado pesquisador da Psicologia da Religião. O artigo apresenta ao leitor/a os dois estágios percorridos por ele em seu itinerário como estudioso da área da Psicologia da Religião.
A construção narrativa da representação de Deus
Authors: Massih Eliana
Published: May 2017

A autora apresenta um modelo de pesquisa baseado em autonarrativas e no construtivismo.  Em respeito à especificidade do objeto religioso, se propõe a investigar a representação de Deus e das experiências religiosas a partir das origens culturais de seus sujeitos de pesquisa. Origens estas que são o fundamento da construção da identidade de grupos e pessoas que têm na religiosidade/espiritualidade um valor central para suas vidas. Apresenta brevemente a Teoria do Self Dialógico como suporte teórico facilitador.
Polyphase Drive Systems Configuration aiming EMI Mitigation
Authors: G. Winnischofer  , C.A.F. Sartori
Published: May 2017

Topologies of motor drive systems are studied, aiming the reduction of common-mode (CM) currents. Initially, the aspects concerning the CM currents circulation are analysed. The reason of common-mode voltages generation, the circulating paths for the resulting CM currents and their effects are discussed. Then, a non-conventional drive system configuration is proposed in order to reduce the CM currents and their effects. This configuration comprehends a non-conventional inverter module wired to a motor with an unusual connection. The cables arrangement differs from the standard solution, too. The proposed topology is compared with other ones, like the active circuit for common-mode voltages compensation. The contribution of the configuration to the reduction of CM voltages and currents and their related interferences are evaluated, based on numerical simulations. Some results are presented and discussed regarding the suitability of the proposed configuration as a potential solution to reduce the CM currents effects, when the state of art and implementation cost of drives are taken into account.
Challenges in Future Distribution Grids - A Review
Authors: M. Arnold  , W. Friede  , J. Myrzik
Published: May 2017

The integration of distributed generation facilities and large loads into the electric grid entails power quality issues. Large scale implementation of renewable and other distributed generation as well as relevant loads like heat pumps into the low and medium voltage grid does not longer allow ignoring the influence of those systems on power quality and stability. Grid codes for different regions started to implement the special re quirements introduced by distributed generation. Distributed generation is able to reduce but also to increase issues regarding network loading and stability or power quality. Optimised grid control, generator control as well as demand and supply side management are identified as suitable solutions for an optimised integration into the distribution grid.
Evaluation of Smoothing Effect of Wind Power Generator Aggregation on Power System Operation
Authors: T. Shimamura  , D. Yamashita  , K. Koyanagi  , Y. Nakanishi  , R. Yokoyama
Published: May 2017

This paper presents an approach to evaluate the smoothing effect of wind power generators on power system operation based on actual wind output data in Tohoku area in Japan. Conventional LFC (Load Frequency Control) model is used and the effect of the smoothing effect on frequency control is evaluated. For evaluating the smoothing effect, spectral analysis and integration of each frequency of wind outputs are utilized. In this study, the smoothing effect in multi areas is evaluated and the decrease of the power spectrum density of individual wind generator is confirmed by comparing with the density of integrated wind generators in wide areas. Moreover, we assume many wind generators are connected to power systems, and analyze the smoothing effect of integrating wind power generators on power system operation. By using this multi generator model, the influence of generator integration on the LFC is evaluated by investigating the change of frequency deviations. In addition, a method to suppress the frequency deviation caused by wind power fluctuations is proposed with control of batteries equipped in Electric Vehicles (EVs)’ in the power system model consists of wind generators and EVs.
Biophotonic Combined Energy System (BCES)
Authors: U. Hellwig  , B. Kamm  , F. Wildenauer  , A. Kölling  , S. Kieseler
Published: May 2017

A comprehensive outline of a new approach in closed loop processing for energy utilisation and biomass genera tion using micro algae for electricity, heat and chemicals is presented - the Biophotonic Combined Energy System (BCES). The basic idea proposes that life-cycle management is an es sential strategy in research and business. In terms of the BCES a carbon cycle driven by solar radiation via the photosystems of the Chlorophyceae species Scenedesmus rubescens serves as the core process from which valuable materials are extracted. The resi dues serve as the substrate for biogas generation which is used to run a Combined Heat and Power Plant (CHP) equipped with a gas motor and an exhaust gas carbon dioxide and heat recovery system. The electricity generated is fed into the public grid and the thermal energy is used to make the right temperature for the micro algae suspension. The carbon dioxide from biogas combus tion is injected into the algae suspension thereby closing the elementary loop within the system.
Mooring for floating offshore renewable energy platforms classification
Authors: L. Castro-Santos  , S. Ferreño González  , V. Diaz-Casas
Published: May 2017

Renewable marine energy has emerged as a centrepiece of the new energy economy, because of its abundance, regularity and to be environmentally - friendly. However, its exploitation in a commercial way is constrained due to several engineering problems. One of the mayor of the major constraints when installing this type of structures grounded on the seabed over 100 meters depth. One of the characteristics of the Spanish oceanic coastal shore is its high depth. So, in order to develop any kind of offshore energy in Spain, floating platforms are needed. Besides all of them should be anchored to the seabed. The aim of this article is to characterize mooring system of several floating offshore platforms which are currently designed to support any type of structure for the exploitation of marine energy (wind, waves or tidal energy).
Improved Structure for Three-Phase Four-Wires Hybrid Active Power Filters
Authors: Lucas Frizera Encarnação  , João Amin Moor Neto  , Mauro Sandro dos Reis  , Mauricio Aredes
Published: May 2017

This paper presents a novel three-phase four-wire low power rating flexible hybrid active filter with a power factor, harmonic and neutral currents capability for distribution systems. The passive filter is tuned to compensate the two largest harmonics components and the power factor of the load. A selective algorithm is employed in order to enable the active filter to compensate only the desirable harmonic components. Simulation results are presented in order to verify the performance of the proposed hybrid filter.
Evaluation of Renewable Energy Technologies in a net Zero Energy Office Building in Germany
Authors: L. Spitalny  , D. Unger  , J. Maasmann  , P. Schwerdt  , B. Van Reeth  , A. Thiemann  , J.M.A. Myrzik
Published: May 2017

Besides increasing requirements for the thermal insulation of buildings, renewable energy sources as photovoltaic-systems as well as heat pumps become more important in the building sector. Until now, there is no sufficient experience of the operation of these units in net zero-energy buildings. Due to this, Daikin Europe NV and Athoka GmbH initiated a test lab to analyse the operation in a daily office routine. To coordinate the power supply and demand of the building, an energy management system is used. To achieve an efficient heating and cooling the operation of two air-to-water and one air-to-air heat pumps was combined. Furthermore, the impact of high reflecting roof coating on the photovoltaic yield was analysed. For this reason, the effectiveness of the energy management system and the combined operation of the heat pumps are evaluated in this paper. In addition, the paper points out the central points for achieving the net zero-energy goal.
Estimation of insulation overheating in Medium Voltage and Low Voltage conductors and transformers due to stationary disturbances
Authors: I. C. Duran  , O. G. Duarte  , A. Pavas
Published: May 2017

This paper presents a method to estimate the insulation lifetime reduction for Medium Voltage (MV) and Low Voltage (LV) conductors and transformers due to the presence of stationary power quality disturbances. Insulation aging can be accelerated by temporary increases of rms values of voltages and currents caused by stationary disturbances, i.e. harmonics. A short duration increase of rms values cannot cause a significant reduction of insulation’s lifetime, but its recurrent presence during long time periods will produce a cumulative effect. Currently available models for insulation aging are employed.
Marine Current Turbines and Generator preference. A technology review
Authors: Astrid Røkke  , Robert Nilssen
Published: May 2017

Marine current power is a significant energy resource yet to be exploited for electricity production. Several novel turbine technologies can be found on the market, and new ones emerge every year. This study found that the most popular choice seems to be the axial flow three-bladed turbine, although the industry has not yet converged to one preferred technology. An overview of the turbine technologies is presented with drive train layout for each device, if this information is obtainable. The majority of manufacturers use geared (mechanical or hydraulic) solutions, and an induction or a synchronous generator. The few direct drive systems all use PM synchronous generators. For prototype turbines there is a trade-off between choosing a proven generator technology that is not optimised for the application, and using a prototype machine that may reduce the number of design iterations.
Analysing low-voltage grids using a behaviour based load profile generator
Authors: N. Pflugradt  , J. Teuscher  , B. Platzer  , W. Schufft
Published: May 2017

This paper contains a behaviour based load profile generator to generate realistic load profiles for every single household in a low voltage grid. The results are compared with measurements and it is shown that adding up all the generated load profiles results in approximately the same load and curve as measured on the real substation. Based on this, the paper shows that the common approach of scaling down standard load profiles to the individual houses yields very different results than using realistic load profiles.
A DC-DC Converter using the Renewable Energies for Battery Charger
Authors: Jin-Hong Kim  , Jun-Hyuk Choi
Published: May 2017

With a development of Hybrid Electric Vehicle (HEV), a photovoltaic(PV) generation system is used for charging batteries in many cases. A dc/dc converter using PV power for a battery charger requires a high efficiency. In this paper, A zero voltage switching (ZVS) boost converter using the renewable energies for HEV charger is proposed. Through the theoretical analysis and experimental result, operation modes and characteristics of the proposed topology are verified.
Interaction of fault ride through requirements and loss of mains protection
Authors: O. Raipala  , A. S. Mäkinen  , S. Repo  , P. Järventausta
Published: May 2017

The strongly growing DG capacity is raising concerns related to unintentional islanding. Unintentional islanding is prohibited due to the associated safety risks, and it is therefore mandatory to equip all DG units with some kind of loss of mains (LOM) protection. However, large amounts of unnecessary tripping of DG units cannot be tolerated anymore as the share of DG has already reached a significant share of the total installed power generation in certain regions. Certain grid codes thus require DG units to be able to ride through remote faults and support the power system. It is generally known that grid codes and LOM protection objectives are of somewhat controversial. However, it appears that no papers have studied the relation of LOM protection performance and fault ride through requirements thoroughly with simulations. This paper aims to fill this gap by providing extensive simulations which show how exactly the grid code requirements affect the performance of LOM protection. The studies are performed in a unique simulation environment consisting of two different types of real time simulators and a real LOM relay.
Harmonic emission study of individual wind turbines and a wind park
Authors: K. Yang  , S. Cundeva  , M. Bollen  , M. Wahlberg
Published: May 2017

The paper analyses the measured emission from four individual modern turbines of about 2MW size equipped with power electronics. The four turbines show different long term spectra and their spectra also show different variations with time. The harmonic emission from individual turbines consists of harmonic and interharmonic spectra. This emission was shown to be low, with the exception of certain non-characteristic frequency components. The measured emission from individual wind turbines has been compared with emission limits. When IEEE Std 519 is applied, for two of the turbines the limits are exceeded for higher odd harmonics. At the same time, these turbines comply with the national French emission limits. Next, a study of the primary harmonic emission of a wind park as a whole was performed. It is concluded that the emission from a park can be higher as well as lower than the emission that would be obtained by adding the harmonic magnitudes of the individual turbine emissions.
Power Quality of Supply Characterization in the Portuguese Electricity Transmission Grid
Authors: L. Campos Pinto  , A. Tavares
Published: May 2017

REN – Rede Eléctrica Nacional S.A., as the concessionaire of the Portuguese National Electricity Transmission Grid (RNT), has an important role in electrical energy quality to the final customer. Continuity of supply general/individual indicators and parameters are defined in accordance to the regulatory legislation stated in the Portuguese Quality of Service Regulation (RQS). Voltage quality assessment is done by REN and is based on a monitoring plan that includes voltage characteristics measurement at selected delivery and internal points. A study was conducted in order to characterize all the bus bars that were monitored between 2010 and 2011. It was used a simple methodology based on labeling the power quality. On this paper, it will be shown this methodology and the results obtained in characterizing the delivery points of the Portuguese Electricity Transmission Grid (RNT) for the period 2010-2011, as well as other REN quality of supply results in the last years.
Solar heating system’s performance for the heating season 2011/12 in Madrid
Authors: P. de Agustin  , M. Izquierdo  , E.Martínez
Published: May 2017

An experimental solar heating system was used to supply partially the heat demand of a laboratory the winter period of 2011-2012. This heating system worked in a solar energy laboratory located close to Madrid (Spain), 8h/day during the whole season. As the dimensions, thermal load and characteristics of occupancy of the laboratory are similar to a Spanish average house, the experimental results’ conclusions could be generalized to national housing. This period (nov11-apr12) was characterized by exceptionally clear-sky and solar irradiative days with an average atmospheric clarity of 0.59 and maximum values over 0.8. The total solar energy radiated was 926 kWh/m2. Collector field’s efficiency was 29%. All this factors implied enough solar energy to supply the 83% of laboratory’s heat demand for the whole season.
Power Quality analysis in Renewable Energy Systems Supplying Distribution Grids
Authors: N. Golovanov  , G.C. Lazaroiu  , M. Roscia  , D. Zaninelli
Published: May 2017

The paper deals with power quality case studies conducted on existing renewable sources based systems. Voltage fluctuations determined by a 0.65 MVA wind turbine are analyzed. The impact of photovoltaic systems on steady state voltage variations and current harmonics is investigated. The correlation between the generated power and the main power quality indices is highlighted.
Experimental investigation on mass transfer for regeneration of liquid desiccant
Authors: S. Bouzenada  , T. Salmon  , L. Fraikin  , A. Kaabi  , A. Léonard
Published: May 2017

Desiccants can be used in conjunction with solar energy to provide a viable alternative to traditional air conditioning techniques. Liquid desiccant regeneration was proved to be an effective method to extract the moisture from solution with a relatively less energy in order to regenerate the desiccant. An experimental study was carried out to analyze the effect of temperature for regeneration process using an injected air through the liquid desiccant solution (calcium chloride dihydrate) by a dryer. Many tests with different operating conditions such as air temperature, humidity ratio, air velocity and solution level are investigated in order to demonstrate that this salt is capable to absorb moisture and can be regenerated at a low temperature. Experimental results showed that the mass transfer is affected by the air conditions. Also, the vapour pressure difference between the air and liquid desiccant surface is the driving force of the mass transfer process. In this analysis it was also determined that the CaCl2.2H2O could be regenerated at low temperature around 48 to 60°C hence the possibility of using the flat plate solar collectors for its regeneration and this salt can be used in a system (LDCS).
Control and simulation of a stand-alone wind-hydrogen generation system
Authors: S. Carr  , F. Zhang  , K. Thanapalan  , J. Maddy  , A. Guwy
Published: May 2017

The potential to produce hydrogen from renewable resources is of considerable interest due to fears over man-made climate change and resource depletion. Hydrogen produced from renewable resources can be used to generate electricity through a fuel cell, or for other uses in a hydrogen economy. There are a number of potential system configurations for hydrogen production from electrolysis including grid connected and stand alone. In remote locations, stand-alone configurations are of interest, and may prove more economically viable than grid connected systems. In this paper a standalone wind - hydrogen generation system is designed and proposed to take advantage of an electrolyser capable of operating at very low power levels. A dynamic model of the system is presented, along with a maximum power point (MPPT) control algorithm of the system. The potential yield of such a wind-hydrogen stand-alone system located at the University of Glamorgan’s Hydrogen Centre is investigated using wind speed data collected at the site and the performance of the system under variable wind conditions determined.
Performance characterization of a PV system using wavelet transform and genetic algorithm
Authors: P. Janik  , P. Kostyła  , J. Rezmer  , J. Szymanda  , T. Sikorski  , Z. Wacławek  , D. Lehmann
Published: May 2017

This paper presents a study of PV system performance in terms of power quality. Wavelet transform has been applied as a tool for signal characterization and future extraction. A Gaussian curve has been proposed as an approximation of daily production. The parameters of the curve were computed using genetic algorithm.
Towards optimal post-fault self-healing in future smart distribution grids
Authors: Florin Capitanescu  , Ilya Bilibin  , Juergen Sachau
Published: May 2017

This paper deals with a key functionality of the future distribution smart grids namely the automatic post-fault network self-healing. To this end we propose an optimization approach that aims finding the post-fault grid topology that minimizes the amount of unsupplied energy to consumers. The approach extends existing optimization models, developed in the context of losses minimization, for our particular application and proposes ways to overcome their limitations. We prove the interest of the approach on a 33-bus benchmark distribution system as well as on a 61-bus real-life distribution grid.
Charging management for full electric vehicles in the mobility-on-demand-concept “fahrE” using local renewable energy
Authors: D. Kühnert  , W. Schufft
Published: May 2017

Unavoidably, the aim of ecologically sustainable driving leads to the use of full electric vehicles (FEVs) and a charging process based on renewable energy. In addition to the ecologically sustainable charging, the additional and high-power load of FEVs in distribution grids can cause problems like overload of electrical equipment and deviations of the preset voltage band. To limit the load and maximize the usage of renewable energy, a management system has to be developed. In this paper, a management system is introduced with the special challenges of mobility-on-demand-concepts, which is one of the main fields of application for FEVs in the early adoption phase. In this system, the real existing local renewable energy, the limit of the electrical equipments, and the permanent availability of mobility influence a charge signal, which is the core of the proposed management. The first results show that the developed management is capable to double the renewable percentage of charging energy in comparison to a dump charging.
Intelligent Management of Alternative Energy Sources Based on Fuzzy Logic
Authors: Christian G. Quintero M.  , José Ledesma  , Jamer R. Jimenez Mares
Published: May 2017

This paper aims to evaluate the use of Soft Computing techniques, specifically Fuzzy Logic for the development of a management system for alternative energy sources such as wind, photovoltaic and fuel cell. The basis of a hybrid generation system checks its response availability, reliability and power supply taking into account the environmental conditions and power consumption. It realizes a comparison of several kinds of supply management in different case studies. Results show which proposed approach reaches a greater use of energy available from such generation systems. Furthermore, it shows the design of a Fuzzy Logic-based manager (FLM), able to select, according to different criteria, which one electrical source and in what proportion, is more suitable to satisfy power consumption. Alternative energy sources models are implemented. Experimental testing is performed to the consumption data base.
A Compression Method for Power Quality Data
Authors: R. E. Dapper  , C. D. P. Crovato  , A. A. Susin  , S. Bampi
Published: May 2017

This paper presents a compression method for power quality (PQ) signals. This method consists of polynomial approximation algorithm and a lossless compression algorithm The proposed method uses the Deflate algorithm as lossless compression algorithm. The polynomial approximation is intended to decrease the entropy of the signal, thus increasing the compression ratio of the Deflate algorithm. The proposed method is characterized by high compression ratio and low computational cost, making feasible its implementation in embedded systems.
Micro-generation and micro combined heat and power generation using “free” low temperature heat sources through Organic Rankine Cycles
Authors: J. Navarro-Esbrí  , B. Peris  , R. Collado  , F. Molés
Published: May 2017

The Organic Rankine Cycle (ORC) technology is an efficient way for small-scale generation. It offers great benefits from low temperature heat sources, recovering waste heat and revaluing renewable thermal energy. This paper presents the use of ORC for power and combined heat and power generation from low temperature heat sources. Specifically, two recent applications successfully implemented in Spain are reported, based on Rank® technology: a micro generation for waste heat recovery in a ceramic industry using HT-20 kWe and a micro combined heat and power generation using solar heat with HT-C 5 kWe. Experimental data have been evaluated to check economical and technical ORC feasibility. From waste heat recovery, now up to 23 kWe are generated, 336 MWt of primary energy are saved and 44 tonnes of CO2 emissions are avoided, with a suitable payback lower than 5 years. From renewable thermal energy, now 37 MWt of primary energy are saved, 5 tonnes of CO2 emissions are avoided with a payback lower than 8 years.
Overview of DC technology - Energy conversion
Authors: O. Oñederra  , H. Odriozola  , E. Planas  , I. López Paniagua  , V. López
Published: May 2017

DC transmission and distribution systems have several advantages compared to classical AC system. This paper presents a review of DC technology, doing a special mention in HVDC. It addresses some issues like HVDC converter types, DC DC converter topologies, DC transmission and distribution topologies, transmission cables and DC circuit breakers with the main manufacturers and commercial devices.
A New Cost-Effective Wind Farm Structure with HVDC Link Preserving Technical Advantages of Advanced offshore Wind Farms
Authors: Ali Shamsnia  , Mostafa Parniani
Published: May 2017

In this paper a review of common wind turbine systems and wind farm configurations with AC and DC links is presented first, and then a new structure based on HVDC local grid is proposed and compared to the existing structures to show its effectiveness with respect to the older ones. The most important feature of the new structure is its lower cost, while it preserves controllability of the most flexible configurations like DFIG-based wind farms or wind farms with PMSG generators and back-to-back converters. The other feature of the proposed structure is its high efficiency, which is due to the use of direct driven multi-pole synchronous generators.
Production of Biodiesel from WVO Using Small Scale Continuous Ultrasonic Processor
Authors: Justin Wood  , Jared Slayton  , Seth Parrott  , Chinyere Mbachu  , Ahmed ElSawy
Published: May 2017

There is a need in the USA to decrease dependency on fossil fuels. One alternative fuel that has gained much popularity in the past few years is biodiesel. Biodiesel can be produced using vegetable oil, waste vegetable oil (WVO), animal fat and yellow grease as raw materials. However, the process of converting a batch of WVO into usable biodiesel is time consuming, requires a human operator to run the system, and necessitates the performance of a chemical titration for each batch of biodiesel produced. In the first phase of this project, the processor was designed and built by the senior design students utilizing a programmable logic controller (PLC) in conjunction with pumps, valves, temperature sensors, etc. to completely handle the production of biodiesel with minimum operator interaction. This was the first step toward continuous flow processor and the elimination of the titration process. In the second phase of this project, the students integrated a small Hielscher Ultrasound continuous processing unit to the automated system. This paper presents the newly developed system and demonstrates the design aspects of the automated biodiesel production processor using a PLC and ultrasonication (continuous processing) as well as how the chemical titration procedure for each batch is eliminated.