bluuebunny/crossref_metadata_2025 huggingface dataset:
The Law of the Wolf: How the Kukryniksy Trio Represented the Enemy as a “Wild” Animal in Cold War Political Cartoons in Pravda, 1965–1982
Authors: Kangas Reeta
Published: May 2017

This article examines how the Soviet Kukryniksy trio used wild animals in their political cartoons to depict the enemies of the Soviet Union. The primary material of this research consists of Kukryniksy’s 39 wild animal cartoons published in Pravda during 1965–1982. For my theoretical and methodological framework, I rely on frame analysis and propaganda theory. My aim is to demonstrate what kind of symbolic functions wild animals have in these cartoons and what kind of characteristics they attach to the enemies depicted. Furthermore, I aim to examine in what kind of frames the world was to be seen according to the Soviet propaganda machine, and how these frames were created with the use of wild animal characters. In these cartoons wild animals are used to reveal the “true” nature of the enemy. The animal’s symbolic functions may derive from the linguistic or other cultural contexts. The cartoons depict the enemy mainly as deceptive and ruthless, but simultaneously predictable to the Soviet Union. They also represent the enemy in a belittling light in order to retain the frame of the superiority of the Soviet Union over its enemies.
Lux-biosensors: screening biologically active compounds for genotoxicity
Authors: Igonina Elena V , Marsova Mariya V , Abilev Serikbai K
Published: May 2017

To study the ability of metal salts and pharmacologically active drugs to induce the oxidative stress and SOS response in bacteria, a set of lux-biosensors was used. The sensors were based on three E. coli strains carrying recombinant plasmids with lux-operon fused to the promoters of SoxS (superoxide dismutase), KatG (catalase-peroxidase) and ColD (colicin D) genes. The created biosensors were used to analyze the activity of 47 substances, with 16 of them identified to induce SOS-response and 6 - to induce oxidative stress. The results observed were compared to the previously published data on the mutagenic activity of the same 47 substances evaluated using Ames test. The comparison had shown full coincidence for 42 from 47 substances analyzed. We discuss the possibility to use the lux-based biosensors for the screening of the genetic activity of chemical compounds.
Apresentação: Christopher Freeman - The 'National System of Innovation' in Historical Perspective
Authors: Albuquerque Eduardo da Motta e
Published: May 2017

Sistema nacional de inovação é um conceito síntese da elaboração evolucionista (ou neo-schumpeteriana): ele expressa o complexo arranjo institucional que impulsionando o progresso tecnológico determina a riqueza das nações. Não é casual que a sua primeira referência explícita tenha sido publicada apenas em 1987, em um livro do próprio Freeman (Technology Policy and Economic Performance: Lessons from Japan).1 Como um conceito que sintetiza a elaboração (ampla) de uma abordagem teórica, sistema nacional de inovação é um conceito que está em aberto, enriquecendo-se dos avanços na elaboração teórica e contribuindo para apresentar novas questões para a reflexão coletiva. Esta abertura permite um diálogo com outras abordagens teóricas na economia e nas ciências sociais...
Innovation and the Development Convention in Brazil
Authors: Erber Fabio Stefano
Published: May 2017

Durante os anos noventa a economia brasileira foi governada por uma visão específica do processo de desenvolvimento econômico que enfatizava o papel do progresso técnico como um meio para atingir crescimento econômico rápido e estável. Não obstante, o grau de inovação tecnológica endógena no Brasil permanece muito baixo. Este artigo explora a conjectura de que este último resultado é uma conseqüência da visão hegemônica de desenvolvimento. A primeira seção do artigo apresenta dados quantitativos e qualitativos para apoiar nossa afirmativa a respeito da inovação da economia brasileira. A segunda seção argumenta que a “visão de desenvolvimento” pode ser tratada como uma “convenção”, um conjunto de crenças compartilhado pelos tomadores de decisão, utilizado para identificar os principais problemas que uma estratégia de desenvolvimento deve enfrentar e os meios adequados para resolver estes problemas. Uma convenção de desenvolvimento contém também uma agenda “negativa” — questões e soluções que devem ser evitados. A mesma seção analisa a convenção de desenvolvimento que foi hegemônica dos anos noventa até a data do artigo (2002) e as implicações de suas agendas — positiva e negativa — para o desenvolvimento tecnológico, supondo que a convenção tivesse funcionado como seus defensores acreditavam. Os resultados hipotéticos são consistentes com os fatos relatados na seção inicial. A última seção comenta o efetivo funcionamento da convenção de desenvolvimento, argumentando que a prática exacerbou as características tecnológicas presentes na “forma pura” da convenção. Na conclusão, discute-se brevemente o papel da inovação numa nova convenção de desenvolvimento que delineava-se à época.
Inovação na Indústria Brasileira: uma Análise Exploratória a Partir da PINTEC
Authors: Kannebley Junior Sérgio , Porto Geciane Silveira , Pazello Elaine Toldo
Published: May 2017

Este artigo reporta um esforço de caracterização das empresas inovadoras industriais brasileiras. Esta caracterização é realizada com base em informações constantes na PINTEC-2000 (Pesquisa Industrial de Inovação Tecnológica-2000). Para isso foram empregados procedimentos estatísticos não-paramétricos, que informaram, em ordem decrescente, que os quatro principais fatores distintivos entre empresas inovadoras e não-inovadoras são: a orientação exportadora, o tamanho da empresa, a origem estrangeira do capital e a variação interindustrial. Também foi conduzida uma análise econométrica para as informações setoriais, onde foi possível complementar e referendar parte dos resultados obtidos para toda indústria.
Government Programme as a Strategy—The Finnish Experience
Authors: Johanson Jan-Erik , Pekkola Elias , Husman Päivi
Published: May 2017

This article uses strategy metaphors consisting of a plan, a home and a game to study government programme formation in Finland. The strategy approach both contradicts and complements the traditional political science approach to government formation, which has been strategic in the sense of separating the formulation and implementation parts of the strategy according to the principles of planning ideas. The adopted austerity policy provides a meagre contribution to the expansion of services and the increase in government spending. Consequently, the home metaphor in the government programme appears in the distant future and in combating external threats. The game metaphor is apparent in the goal of making contracts with social partners. The vocabulary change from politics to strategy alters the government programme’s position in terms of catering to the needs of civil servants, citizens and stakeholders. The strategy perspective might be instrumental in shifting open democratic debates to closed and secretive policy formations.
Backtesting the Lee-Carter and the Cairns-Blake-Dowd Stochastic Mortality Models on Italian Death Rates
Authors: Maccheroni Carlo , Nocito Samuel
Published: May 2017

The work proposes a backtesting analysis in comparison between the Lee-Carter and the Cairns-Blake-Dowd mortality models, employing Italian data. The mortality data come from the Italian National Statistics Institute (ISTAT) database and span the period 1975-2014, over which we computed back-projections evaluating the performances of the models in comparisons with real data. We propose three different backtest approaches, evaluating the goodness of short-run forecast versus medium-length ones. We find that both models were not able to capture the improving shock on the mortality observed for the male population on the analyzed period. Moreover, the results suggest that CBD forecast are reliable prevalently for ages above 75, and that LC forecast are basically more accurate for this data.
Power and Obstacle Aware 3D Clock Tree Synthesis
Authors: Chandrakar Leena , S. Ravi , Kittur Harish M.
Published: May 2017

Clock Network Design (CDN) is a critical step while designing any Integrated-Circuits (ICs). It holds vital importance in the performance of entire circuit. Due to continuous scaling, 3D ICs stacked with TSV are gaining importance, with an objective to continue with the Moore's law. Through-Silicon-Via (TSV) provides the vertical interconnection between two die, which allows the electrical signal to flow through it. 3D ICs has many advantages over conventional 2D planar ICs like reduced power, area, cost, wire-length etc. The proposed work is mainly focused on power reduction and obstacle avoidance for 3D ICs. Various techniques have already been introduced for minimizing clock power within specified clock constraints of the 3D CND network. Proposed 3D Clock Tree Synthesis (CTS) is a combination of various algorithms with an objective to meet reduction in power as well as avoidance of obstacle or blockages while routing the clock signal from one sink to other sink. These blockages like RAM, ROM, PLL etc. are fixed during the placement process. The work is carried out mainly in three steps- first is Generation of 3D Clock tree avoiding the blockages, then Buffering and Embedding and finally validating the results by SPICE simulation. The experimental result shows that our CTS approach results in significant 9% reduction in power as compare to the existing work.
Abnormal Magnetic Moment and Zero Field Splitting of Some Nickel (II) Complexes
Authors: Ranjan Rajeev , Sinha Navneet , Kumar Sahdeo , Chandra Chandra Mauleshwar , Sharma Shivadhar
Published: May 2017

Some complexes of Ni(II) have been prepared with 2-thio-3-acetyl hydantoin (TAHN) and 2-formyl pyridine thiosemicarbazone (FPTS). On the basis of elemental analysis and molar conductivity, the complexes have been formulated as NiL2X2, where L = TAHN or FPTS and X = Cl–, Br–, NCS–, ClO4–. The infrared spectra of complexes and free ligand reveal that the ligand TAHN is co-ordinated through sulphur and acetyl oxygen, while FPTS ligand co-ordinates through heterocyclic nitrogen and sulphur to Ni(II) metal ion. The magnetic moment of these complexes are found to be 3.20-3.25 B.M. The values are greater than value (2.828 B.M) corresponding to two unpaired electrons of a d8-system. The appearance of four absorption bands in their electronic spectra reveal, the tetragonal distortion in the octahedral symmetry of complexes. The zero field splitting parameter(D) and the other crystal field parameters like Dq(xy), Dq(z), Dt have been calculated. The results show that, the tetragonal distortion parameter (Dt) increases in the order of NCS– < Cl– < Br– while the zero field splitting parameter (D) also increases in the same order for both the planer ligands.
Experimental study on performance of sand filter layer to remove non-point source pollutants in rainwater
Authors: Ahn Jaeyoon , Lee Dongseop , Han Shinin , Jung Youngwook , Park Sangwoo , Choi Hangseok
Published: May 2017

Clogging characteristics of conventional sand filter layers with different grain-size distributions were experimentally studied to estimate their filtration capacity to capture non-point source pollutants in an artificial rainwater reservoir. A series of laboratory-scale chamber tests was conducted for artificial urban runoff synthesized with non-point source pollutants collected from a real road in Seoul, Korea. In addition, an analytical filtration model for estimating removal of non-point source pollutants was adopted considering the clogging characteristics. To evaluate the performance of three types of sand filter layers with different grain size characteristics, the pollutant concentration was measured in terms of total suspended solids and chemical oxygen demand. The lumped parameter (θ) related to the clogging property was estimated by comparing the accumulated weight of pollutant particles obtained from the laboratory chamber experiments and the theoretical estimation from the analytical filtration model. Based on the experimental study and theoretical consideration, a double-sand-filter layer consisting of two separate layers is proposed as the optimum system for removing non-point source pollutants in the pilot-scale rainwater reservoir.
The Relationship Between Green Building and Regional Economy: A Case Study in Guangdong, China
Authors: Likun Zhao , Qibin Zhang , Yingbo Ji
Published: May 2017

Developing Green Building (GB) is one of the most effective measures to save energy and reduce carbon emissions in the world. To promote the development of green building, it is necessary to analyze driving factors and contribution through the analysis for relationship between regional economy and green building. Therefore, based on the system dynamic(SD) theory, this paper constructs the structure model of the stock flow diagram, including the regional economic subsystem, social subsystem, government support subsystem and green building subsystem. Among the model, Guangdong province, as the most prosperous province of economic development with the largest numbers of certified green buildings in China, has been chosen to show the influence level of their relationship. Through simulation, results can be easily shown that development of GB can make contributions to the field of local economy, however, also be limited by the regional condition, including policy incentive, regional economic, technological, etc. We can also find that direct contribution to the GDP the Green Building made can reach about 2.47 ‰, and 9.23 ‰ indirectly. If the current level of regional production is stable, it can be found that each additional 10,000 square meters of green area building may produce about ¥018.2 million for economy. On the contrary, that the regional economy investment in fixed assets increased by ¥1 million can stimulate 0.001648 million square meter demand of GB. Additionally, employment opportunities directly or indirectly have also been considered.
Merging the A-and Q-spectral theories
Authors: Nikiforov V.
Published: May 2017

Let G be a graph with adjacency matrix A(G), and let D(G) be the
diagonal matrix of the degrees of G: The signless Laplacian Q(G) of G is
defined as Q(G):= A(G) +D(G). Cvetkovic called the study of the adjacency
matrix the A-spectral theory, and the study of the signless Laplacian{the
Q-spectral theory. To track the gradual change of A(G) into Q(G), in this
paper it is suggested to study the convex linear combinations A_ (G) of A(G)
and D(G) defined by A? (G) := ?D(G) + (1 - ?)A(G), 0 ? ? ? 1. This study
sheds new light on A(G) and Q(G), and yields, in particular, a novel
spectral Tur?n theorem. A number of open problems are discussed.
A note on the Nordhaus-Gaddum type inequality to the second largest eigenvalue of a graph
Authors: Abreu Nair , Brondani André , de Lima , Oliveira Carla
Published: May 2017

Let G be a graph on n vertices and G? its complement. In this paper, we prove
a Nordhaus-Gaddum type inequality to the second largest eigenvalue of a graph
G, ?2(G), ?2(G) + ?2(G?) ? -1 + ? n2/2-n+1, when G is a graph with girth
at least 5. Also, we show that the bound above is tight. Besides, we prove
that this result holds for some classes of connected graphs such as trees,
k-cyclic, regular bipartite and complete multipartite graphs. Based on these
facts, we conjecture that our result holds to any graph.
Intestinal lymphangiectasia in dogs, challenging diagnosis: Four cases
Authors: Davitkov Darko , Vasiljevic Maja , Davitkov Dajana , Bozovic-Ilic Anja , Djordjevic Milena , Krstic Vanja
Published: May 2017

Intestinal lymphangiectasia is an uncommon disease which can cause severe,
chronic protein-losing enteropathy in dogs. Four dogs were presented at the
Belgrade Clinic for Small Animals with clinical signs of chronic diarrhea,
lethargy, anorexia, vomiting and weight loss. Abnormal physical examination
findings included dehydration, signs of pain on abdominal palpation, and
ascites. The most important clinicopathological findings were lymphopenia and
hypoproteinemia with hypoalbuminemia. Abdominal ultrasound revealed
intestinal abnormalities in all dogs. To establish an undoubted diagnosis of
intestinal lymphangiectasia, endoscopy and histopathology were conducted.
Hypoglycemic Effect of Combined Ghrelin and Glucagon Receptor Blockade
Authors: Mani Bharath K. , Uchida Aki , Lee Young , Osborne-Lawrence Sherri , Charron Maureen J. , Unger Roger H. , Berglund Eric D. , Zigman Jeffrey M.
Published: May 2017

Glucagon receptor (GcgR) blockade has been proposed as an alternative to insulin monotherapy for treating type 1 diabetes since deletion or inhibition of GcgRs corrects hyperglycemia in models of diabetes. The factors regulating glycemia in a setting devoid of insulin and glucagon function remain unclear but may include the hormone ghrelin. Not only is ghrelin release controlled by glucose but also ghrelin has many actions that can raise or reduce falls in blood glucose level. Here, we tested the hypothesis that ghrelin rises to prevent hypoglycemia in the absence of glucagon function. Both GcgR knockout (Gcgr−/−) mice and db/db mice that were administered GcgR monoclonal antibody displayed lower blood glucose levels accompanied by elevated plasma ghrelin levels. Although treatment with the pancreatic β-cell toxin streptozotocin induced hyperglycemia and raised plasma ghrelin levels in wild-type mice, hyperglycemia was averted in similarly treated Gcgr−/− mice and the plasma ghrelin level was further increased. Notably, administration of a ghrelin receptor antagonist further reduced blood glucose levels into the markedly hypoglycemic range in overnight-fasted, streptozotocin-treated Gcgr−/− mice. A lowered blood glucose level also was observed in overnight-fasted, streptozotocin-treated ghrelin receptor–null mice that were administered GcgR monoclonal antibody. These data suggest that when glucagon activity is blocked in the setting of type 1 diabetes, the plasma ghrelin level rises, preventing hypoglycemia.
Protective Effect of let-7 miRNA Family in Regulating Inflammation in Diabetes-Associated Atherosclerosis
Authors: Brennan Eoin , Wang Bo , McClelland Aaron , Mohan Muthukumar , Marai Mariam , Beuscart Ophelie , Derouiche Sinda , Gray Stephen , Pickering Raelene , Tikellis Chris , de Gaetano Monica , Barry Mary , Belton Orina , Ali-Shah Syed Tasadaque , Guiry Patrick , Jandeleit-Dahm Karin A.M. , Cooper Mark E. , Godson Catherine , Kantharidis Phillip
Published: May 2017

The let-7 miRNA family plays a key role in modulating inflammatory responses. Vascular smooth muscle cell (SMC) proliferation and endothelial cell (EC) dysfunction are critical in the pathogenesis of atherosclerosis, including in the setting of diabetes. Here we report that let-7 levels are decreased in diabetic human carotid plaques and in a model of diabetes-associated atherosclerosis, the diabetic ApoE−/− mouse. In vitro platelet-derived growth factor (PDGF)– and tumor necrosis factor-α (TNF-α)–induced vascular SMC and EC activation was associated with reduced let-7 miRNA expression via Lin28b, a negative regulator of let-7 biogenesis. Ectopic overexpression of let-7 in SMCs inhibited inflammatory responses including proliferation, migration, monocyte adhesion, and nuclear factor-κB activation. The therapeutic potential of restoring let-7 levels using a let-7 mimic was tested: in vitro in SMCs using an endogenous anti-inflammatory lipid (lipoxin A4), ex vivo in murine aortas, and in vivo via tail vein injection in a 24-h murine model. Furthermore, we delivered let-7 mimic to human carotid plaque ex vivo and observed significant changes to the secretome in response to let-7 therapy. Restoration of let-7 expression could provide a new target for an anti-inflammatory approach in diabetic vascular disease.
THE USE OF DIGITAL SIGNAL PROSESSING CARD IN ACTIVE POWER FILTER DESIGN TO MITIGATE HARMONIC DISTORTION
Authors: Daniel Rohi  , Limboto Limantara  , David Wailanduw  , Resmana L  , Stephanus Ananda  , Yusak Tanoto
Published: May 2017

Nowadays most of factories use non-linear loads, such as VSD (Variable Speed Drive), rectifier, UPS system, computer, etc. They cause the harmonics and will be reduce the cost of power quality in the electric distribution system. Harmonics also influence the performance of the loads, which is used in that system.To reduce the harmonics in the system, we applied active filter by using a DSP card that connected with a PC. A sinusoidal waveform distorted with the harmonics will be processed, by using LabView 7 software, so the harmonics could be reduce or eliminated.By using DSP card, the harmonics which appear in the system, caused by of non-linear loads usage, can be reduced until 25th harmonics, so the cost of the power quality in that system will increased. In this case, we using a Sheldon Instrument’s DSP Card, SI-C33DSP-PCI, which is plugged by an analog I/O module, SI-MOD68xx, which is used for signal processing inside the computer. Furthermore, we must add a library for LabView 7, called QuVIEW, which is used to operate that DSP card.From the anlaysis that have been done, we can take a conclusion, the cost average of eliminated harmonics in distorted waveform is up tu 80%. Which on pure triangle waveform, cost of %THD decreased from 13.4376% become 3.12239%
Influence of the photovoltaic generation in a small distribution network
Authors: E. Tarancón Andrés  , L.A. Fernández Jiménez  , E. García Garrido  , A. Falces de Andrés  , P. Lara Santillán  , P. Zorzano Santamaría
Published: May 2017

In this paper are presented the results of a study carried out with the data of a electrical energy distribution network in a village in the region of La Rioja (Spain). In this distribution network, property of a small utility, is connected a photovoltaic power plant with a capacity comparable with the total load connected to the network in some hours. In the study there have been used actual load and generation data, discussing the influence of the photovoltaic generation on the net demand of the village over a period of two years (2009-2010). This study is a first phase for the application of demand side management actions for adjusting the load curves with generation curves. In a second phase the influence of new distributed generation facilities, based on renewable sources (wind, biomass, cogeneration, etc.) will be considered in order to minimize the dependence of the village from external supplies.
Power Line Tower Lightning Surge Impedance Computation, a Comparison of Analytical and Finite Element Methods.
Authors: P. C. A. Mota  , M. L. R. Chaves  , J. R. Camacho
Published: May 2017

The aim of this work is to compare methods for the computation of transmission line tower surge impedance, that are: traditional analytical method using simplified equations; and the Finite Element Method for the mapping of electromagnetic fields surrounding the tower[9]. In the latter were used two different software, the public domain FEMM, and the commercial software FLUX3D. The first is able to perform calculations based in a 2D representation of the problem while the second uses a 3D representation of the problem to perform computations. It is also verified the impedance variation along the tower height, phenomenon that most of the time is not considered, and that can provide a direct impact in the performance of transmission lines facing the atmospheric discharges. With this purpose it was used the software ATP-EMTP, where it was modeled a simple case who brought results for immediate comparison.
Converter with Wide Input Voltage Range Applied to Solid State Lighting Based on HV9930
Authors: R. A. Lodo  , E. A. A. Coelho  , F. V. R. Da Silva  , A. W. F. V. Silveira  , L. C. G. Freitas  , J. B. Vieira Jr
Published: May 2017

Currently research has pointed to LEDs as the technology more efficient and durable to be used in lighting, however, it requires a static converter in order to control the electrical current flowing through the LED lamp. In this context, this paper describes the implementation of a DC/DC converter with wide input voltage range called Boost-Buck Quadratic, with simple control strategy, driving a LED lamp. The converter can be powered from 12 VDC (battery voltage) to the universal AC input voltage (90 to 240 VAC). Theoretical analysis, design guidelines and experimental results from a prototype of the proposed Boost-Buck Quadratic converter driving a 12 W LED lamp are shown in this paper.
Reactive Power- and Voltage Regulation in Micro Grids
Authors: Istvan Vokony  , Andras Dan
Published: May 2017

This paper is a continuation of the paper Examination Of Micro Grid Operation In Island Condition, Focusing On Voltage Control [10]. It has presented the assessment of micro grids’ voltage and reactive power control. The increasing integration of intelligent energy distribution networks has to serve the interest of the consumers. Therefore it is necessary to examine the quality of the electricity supply with regard to the voltage quality as well. How is it possible to ensure the regulation in those cases e.g. in case of island operation. In the paper the model developed and used for simulating the micro grids is introduced, and it is also shown, how to apply them for island operation assessment. With the help of a model network the results of the simulations are presented and the conclusions are evaluated
Experimental DTC of an Induction Motor Applied to Optimize a Tracking System
Authors: B. Mokhtari  , A. Ameur  , M. F. Benkhoris  , L. Mokrani  , B. Azoui
Published: May 2017

In recent years, the areas of industrial application of high performance AC drives, especially the induction motor (IM), based on Direct Torque Controller (DTC) technique has gradually increased due to its advantages over the other techniques of control. Among these applications are cited, propulsion and tracking systems. This work presents the experimental part of a research project conducted by the authors where they have implemented an algorithm for a DTC in order to achieve a tracking system designed for a series of solar panels to maximize its overall efficiency. In this paper, three different switching tables are presented for choosing the best between them for a less fluctuation in torque. This study is justified by reduced cost of implementation compared to other methods that require the use of expensive hardware and complicated control techniques. The tests were carried out under the same conditions with the same equipment of the testbed, to get a good comparative study. Three variants were tested: simple switching table, table of sectors shifted by 30 ° and a table with 12 sectors. The results show an improvement, but a dilemma between the torque ripple and those of the stator flux.
Multifunctional Single-Phase Single-Stage Grid-Connected PV System
Authors: A. Helal  , A. Nour  , I. El-Mohr
Published: May 2017

This paper presents the analysis of a multifunctional single-phase single-stage grid connected photovoltaic (PV) system. The primary function of the grid connected inverter in a single stage (PV) system is to supply active power to both load and grid in a way that complies with the applied grid connection standards. The added functions to the grid connected inverter are compensation for reactive power requirements and mitigation of the harmonics produced by the nonlinear loads connected to the point of grid connection. The single stage topology utilized in the grid connected PV system has the advantages of high efficiency and low cost compared with the two stage topology. Maximum power point tracking (MPPT) is achieved using perturb and observe algorithm. A test system composed of the PV array, single phase inverter, single phase supply, and three different types of single phase loads is modeled to evaluate the performance of the multifunctional operation of the PV grid connected system. The results of the test system simulation, using MATLAB/Simulink environment, validate the effectiveness of the system to perform the multifunctional operation of the grid connected inverter.
Efficiency Analysis of Single-Phase Photovoltaic Transformer-less Inverters
Authors: M. Martino  , C. Citro  , K.Rouzbehi  , P. Rodriguez
Published: May 2017

This paper presents an efficiency analysis of five single-phase transformer-less inverters for photovoltaic applications (Full H-Bridge, Half H-Bridge, H5, HERIC and NPC inverters) implemented with different topologies of switches. Silicon (Si) and Silicon Carbide (SiC) diodes have been considered combined with two kinds of IGBTs. Simulation results have been obtained for each of the systems in different operating conditions by using PLECS software. Power losses and European Efficiency (EE) have been calculated for all the topologies by including the real characteristics of the switches in the thermal models provided by the software
DFT-based controller for sag and harmonic mitigation with a series-connected compensator
Authors: Javier Roldan-P ´ erez  , Juan Luis Zamora-Macho  , Aurelio García-Cerrada
Published: May 2017

Voltage-quality  problems  in  power  distributionnetworks  include  harmonics,  voltage  sags  and  swells  andunbalances.  These  problems  may  seriously  affect  sensitiveindustrial loads causing production interruption or equipmentdamage. Now-a-days series voltage compensation using powerelectronics devices is a promising solution for these problemsand the design, control and application of this type of deviceshave  drawn  much  attention in the literature.  In fact,  compre-hensive  controllers  for  power  electronics  series  compensatorhave already been proposed in the literature to tackle all thoseproblems  simultaneously.  For  example,  repetitive  controllersshow  very  promising  performance  although  several  aspectsstill  need  closer  attention.  This  paper  proposes  a  differenttype  of  controller  based  on  a  Discrete  Fourier  Transform  tominimise voltage harmonic pollution using power electronicsseries  devices.  The  design  process  of  this  type  of  controlleris  straightforward  regardless  of  the  number  of  harmonics  tobe  tackled.  In  addition,  the  proposed  controller  uses  a  slowsampling rate and its computational effort is relatively low. Themain contributions of this paper are illustrated by simulation.
Obtaining and Characterization of Biodiesel Water Emulsion
Authors: J. Aponte  , L. Llano  , V. Prada  , A. Martinez
Published: May 2017

This paper describes the obtaining process results of a biodiesel-water emulsion, which seeks to obtain a non-fossil fuel whose characteristics comply with its possible use in diesel engines ensuring fewer toxic emissions into the environment, for it to be made tests with different proportions were realized, having previously chosen the correct emulsifier for this application.
Operating conditions on the performances of SOFC fuelled with methane
Authors: A. Musa  , A. Agina  , M. Talbi
Published: May 2017

Both  high  temperature  (HT)  and  intermediate temperature   (IT)   SOFC   performances   are   evaluated   using validated  models  for  the  internally  reformed  (IR)  fuel  cells. Moreover, several SOFC cycles are proposed and investigated. A parametric  study  is  performed  to  evaluate  the  effect  of  various parameters  such  as  turbine  inlet  temperature,  operating  pressure, and  fuel  recirculation  rate  on  the  system  performance.  The  HT-SOFC and the IT-SOFC cycles are simulated in order to evaluate and  compare  their  performances.  The  simulation  results  show that  the  electrical  outputs  from  the  SOFC  and  gas  turbine  are increased    simultaneously    by    increasing    the    turbine    inlet temperature.  Furthermore,  the  efficiency  for  the  IT-SOFC  cycle is found be the higher than the efficiency for the HT-SOFC cycle.
Sizing and Control of the Electric Power Take Off for a Buoy Type Point Absorber Wave Energy Converter
Authors: V.C. Tai  , P.C. See  , S. Merle  , M. Molinas
Published: May 2017

This paper presents the study of power extraction and control of the electric power take off of a buoy type point absorber wave energy converter in heave. Two fundamental linear control strategies (the passive loading and optimum control) have been studied and their impacts on the sizing of generator were investigated. For the designed incident wave, a gearbox is needed to reach the rated speed of the generator. The generator is connected to the grid through a back-to-back converter which controls the electrical torque. Vector control technique is implemented to control the electric torque of the generator, by setting the direct axis current to zero. The results show that the current needed to control the electrical torque is too high for optimum control strategy. A method has been presented to reduce the power ratio significantly, but also with a decrease in average extracted power.
A Matrix converter-interfaced PM Generator System with Active Filtering Capabilities
Authors: N. Holtsmark  , M. Molinas
Published: May 2017

In  this  paper  is  presented  a  matrix  converter- interfaced Permanent Magnet (PM) generator system which can provide  shunt  active  filtering  in  addition  to  converting  and transferring energy. The modulation technique is the simple and well-known  indirect  space  vector  modulation.  The  filtering current  injected  by  the  matrix  converter  and  the  input  filter capacitor   voltage   are   controlled   by   cascaded   proportional control   loops.   Results   showing   that   the   matrix   converter successfully    provides    active    power    filtering    are    given. Simulations  also  indicate  that  the  filtering  capability  of  the system   depends   on   the   generator   side   power   factor.   An explanation to this effect is given.
Gossip Sensor Networks for Power Quality Monitoring in Smart Grids
Authors: S. L. Ullo  , A. Vaccaro
Published: May 2017

This paper intends to give a contribution towardthe  definition  of  a  fully  decentralized  power  quality  moni-toring architecture by proposing the employment of Gossipsensor networks.  According to this paradigm each node canassess both the performances of the monitored site, computedby acquiring local information, and the global performancesof the monitored grid section, computed by local exchangesof information with its neighbors nodes. Moreover, thanks tothis feature each node could automatically detect local powerquality anomalies.   System operators can assess the systempower  quality  index  for  each  grid  section  by  inquiring  anynode of the corresponding sensor network without the needof a fusion center acquiring and processing all node acquisi-tions.  This makes the overall monitoring architecture highlyscalable, self-organizing and distributed.
Power Flow Solution on Multi-Terminal HVDC Systems: Supergrid Case
Authors: F. Gonzalez-Longatt  , J. Roldan  , C. A. Charalambous
Published: May 2017

High Voltage Direct Current (HVDC) systems offer distinct advantages for the integration of offshore wind farms to inland grid system. HVDC transmission system based on Voltage Source Converter (VSC) enables multi-terminal use HVDC for the integration of large-scale wind power in the North Sea. That network requires a special formulation for power flow analysis as opposed to the conventional method employed on AC networks. This paper presents a sequential AC/DC power flow algorithm, which is proposed for the analysis of multi-terminal VSC HVDC (VSC-MTDC) systems. This sequential power flow method can be implemented easily in an existing AC power flow package and is very flexible when compared with unified methods. Gauss-Siedel is used to solve DC power balance equations, as it offers two keys advantages: very fast and simple computational implementation, and errors do not accumulate during the calculation. The algorithm is tested using the WSCC 3-machine, 9-bus system with a 3-terminal MTDC network and the results are compared with those obtained from DIgSILENT PowerFactoryTM demonstrating the validity of the proposed algorithm. As an aggregate value, a representative test case of the projected scheme for the phase I of the Supergrid project on the North Sea is presented. The proposed approach presented in this paper is used to calculate DC power flows for some scenarios.
Performance Analysis of SOFC Systems Integrated with Steam Reforming of Different Renewable Fuels
Authors: D. Saebea  , A. Authayanun  , Y. Patcharavorachot  , W. Paengjuntuek  , A. Arponwichanop
Published: May 2017

This study presents the performance analysis of a solid oxide fuel cell (SOFC) system integrated an external steam reforming process. Various renewable fuels such as ethanol, glycerol and biogas, are considered. Effect of key operating parameters of a steam reformer on hydrogen production for SOFC is investigated. The performance of the SOFC systems fed by different fuels in terms of electrical and termal efficiencies is compared. The results show that the biogas-fuelled SOFC system required the highest energy supply. The SOFC fed by ethanol can achieve the highest electrical and thermal efficiencies.
Developing a Dynamic Smart Grid Model
Authors: I. Vokony  , B. Hartmann  , Dr. A. Dan
Published: May 2017

The aim of the research was to create a computer simulation model of the future smart grid systems, suitable to examine their operation and optimal control. The model is able to simulate events in arbitrary system cases and the answers of the system. The flexibility of the simulation is foreseen by the modular structure of the software. The generation and consumption data are based on real measured values. Different size and number of smart grids were examined by using this model. The actual result of the research was that the system’s behavior, as simulated by the model, was similar to the everyday operation of a real grid. Furthermore, the model is a tool to investigate the trends of future network development (regarding the change of smart grid criteria). There is a need to work out new application behaviors, procedures, and operational routines regarding the research areas represented by certain modules. The computer simulation model is already ready to use in the education, and as it is extensible, it is suitable to follow the changes of smart systems in the future.
Dimming Compatibility of 60W Replacement LED Lamps with Legacy Dimming Infrastructure
Authors: A. Boura  , M. Husak
Published: May 2017

The paper summarizes basic problems of dimming compatibility of modern LED lamps with the legacy dimming infrastructure. In 2016 the legacy incandescent bulbs are going to be forbidden on the European market and thus it must be replaced by modern and energy efficient solid state lighting. The problems with dimming compatibility appeared. Standards phase-cutting dimmers are widely used in the households and consumers expect the modern lighting to have the same properties as the incandescent bulbs. The legacy dimmers are designed for some minimal load (usually 40 – 60 W) while the modern LED lamps replacements have only about 12 W keeping the 60 W incandescent bulb luminous flux (800 lm). Several different problems must be solved in order to keep the dimming ability, avoid the light flickering and keep the dimmer in the safe operation region. There are two basic dimmer types. The leading edge dimmers that are usually based on triac switch and trailing edge dimmers that use MOSFET switches and electronic control. Both types have its specific demands and need different approach for ensuring the dimming compatibility. New LED driver must be developed in order to be compatible with the legacy dimmers.
Flicker assessment performance of an Electrical Power Standard
Authors: J. Bruna  , J. M. Castell  , D. Cervero  , M. A. García  , J.J. Melero
Published: May 2017

This paper presents a flicker compliance testing method useful for the evaluation of electrical power standards. The method uses a very precise self-developed flicker generator based on discrete power semiconductors. Pst, frequency and voltage variations can be accurately compared to assess the performance of flicker generators. A digital flickermeter has also been developed and it is used to obtain the results of the most characteristic flicker parameter, Pst. With this approach, it is possible to assess the performance of flicker generator standards in consistency with the latest IEC flickermeter testing standard edition.
2.3 MW Biomass Steam Power Plant: Experimental and Thermodynamic Analysis
Authors: A. Gimelli  , A.Luongo
Published: May 2017

The present paper shows the experimental and numerical analysis of a biomass plant from maximum power of 2.3 MW. This is a classical Steam Power Plant with a maximum pressure of 48 bar and a turbine inlet temperature of about 430 °C at the design point. The size is significantly smaller than the mean of this t system [1], [2], [3], [4], but maintains a relative high value (about 22.9%) of the Global Electric Efficiency. The analysis was conducted using experimental data, collected directly on the Power Plant, at the Design Point, and thus validating thermodynamic models. The difficulty in collecting the experimental data of this type of system, is mainly due to the enormous variability of the lower heating value of biomass, which involves a large variability of the load and then the operating parameters. Combustion simulation was experimental data (Flue gas temperature, air flow, fuel flow) and the results allowed the evaluation of the biomass composition that is within the range reported in the literature [5]. Different Plant configurations were, numerically, evaluated to plug the power fluctuations due to variability of biomass. A 100 kWe Natural Gas fuelled Turbine (MGT) was numerically connected to the Steam Power Plant (BSPP) to evaluate the benefits on the power fluctuations and on the Global Electric Efficiency. A MGT thermodynamic scheme has been developed and, properly, validated with experimental data from literature [6] e [7]. It is designed to send the hot gases coming from the exit of the MGT in the combustion c main system, thus creating a MGT-ST Analysis of the results of this coupling has noticed an improvement in terms of efficiency and operational stability
Complete methodology on generating realistic wind speed profiles based on measurements
Authors: C. Gavriluta  , S. Spataru  , I. Mosincat  , C. Citro  , I. Candela  , P. Rodriguez
Published: May 2017

The  wind  speed  represents  the  main  exogenous signal applied to a Wind Energy Conversion System (WECS) and determines  its  behavior.  The  erratic  variation  of  the  wind  speed, highly  dependent  on  the  given  site  and  on  the  atmospheric conditions,   makes   the   wind   speed   quite   difficult   to   model. Moreover,  wind  modelling  for  medium  and  large  time  scales  is poorly   treated   in   the   present   literature.   This   paper   presents methods for generating realistic wind speed profiles based on real measurements.  The  wind  speed  profile  is  divided  in  a  low-frequency  component  (describing  long  term  variations)  and  a turbulence  component  (corresponding  to  fast,  high  frequency variations).  For  modelling  the  low  frequency  component  two methods  are  implemented  and  compared:  one  based  on  the  Van der  Hoven  spectrum  and  one  based  on  auto  regressive  models. The importance of the turbulence component is also analyzed and modelling methods based on white noise filtering are presented.
Simulink Based Model of PV Plant
Authors: Silvano Vergura
Published: May 2017

The   paper   proposes   the   Simulink   based   model   of   a   grid-connected PV plant. The model considers standard monocrystalline  PV  modules,  even  if  any  typology  of  sylicon based PV module can be used, because the values of the technical specifications  can  be  easily  modfied  by  the  user  by  means  of masks.  The  proposed  model  considers  a  multi-inverter  PV  plant with   local   MPPT,   implementing   the   Perturbe   and   Observe strategy.  Moreover,  also  the  models  of  the  interface  protection device,  of  the  coupling  capacitor  and  of  the  L-filter  have  been implemented,   allowing   to   modify   the   characteristic   values. Several  simulation  results  are  presented  in  this  paper  and  they agree with the expected values.
A reactor for rapid water disinfection in rural areas and post disaster situations
Authors: S. Ali Shah  , R. Saunders
Published: May 2017

Solar   Disinfection   (SODIS)   is   the   method   usually   applied internationally to purifying  water in rural areas  when pipe borne water  is  not  available.  Using  Poly  Ethylene  Terephtalate  (PET) bottles   the   process   takes   4   hours   under   the   environmental conditions  of  Trinidad  and  Tobago.  We  have  built  and  tested  a portable  reactor  for  decontamination  on  a  larger  scale  than  that possible  with  bottles.  The  active  surface  of  this  reactor  is  a coating of titanium dioxide nanoparticles on frosted glass or on a flexible  plastic  surface  coated  with  glass  ballotini  of  average diameter  0.5  mm.  The  plastic  surface  is  more  suitable  for  use  in rural  areas  and  post  disasters  situations.  In  each  case  Titanium dioxide nanoparticles (35nm)  were deposited by a sedimentation process. E. coli contaminated water placed in the reservoir of the reactor  was  pumped  over  the  active  surface  at  a  rate  of  48  L/hr while  it  was  exposed  to  sunlight.   E.  coli  degradation  was  rapid for  the  both  surfaces,  total  elimination  taking  place  within  10  to 30   minutes   depending   on   the   solar   conditions. The   photo-catalytic  effect  of  titanium  dioxide  in  the  presence  of  ultraviolet light is the main contributor to the observed decrease in bacterial concentration.  Titanium  dioxide  absorbs  ultraviolet  light  from short  wavelengths  up  to  385nm  and  is  known  to  be  effective  in solar detoxification.
Seamless disconnection and reconnection transients for Micro-Grids
Authors: J. Rocabert  , A. Luna  , I. Candela  , P. Rodriguez
Published: May 2017

The increasing penetration of generation power plants based on renewable energies in the electrical networks has boosted the number of systems connected to the grid. In this scenario the micro-grid, providing advanced functionalities to improve the stability and operation of the network, have become very popular. In this paper a control strategy for the micro-grid management is presented. The proposed system improves the performance of micro-grids and its interaction with the main network, or also with other micro-grids, under grid voltage transients. This technique gives rise to a simple and robust control scheme to ensure the appropriate micro-grid disconnection from the main grid. In the following, the control algorithm for the intelligent connection agent will be shown, and the grid synchronization system, as well as the voltage and current control loops will be detailed. Finally simulation results obtained using the MATLAB/Simulink & Psim platform will be presented and discussed
Development of Molybdenum trioxide (MoO3) by spin coating method for photovoltaic application
Authors: L.Chibane  , MS.Belkaid  , M. Pasquinelli  , H.Derbal-Habak  , J-J. Simon  , D.Hocine  , O.Boudia
Published: May 2017

Molybdenum trioxide, MoO3 , thin films have been deposited on glass substrates by Spin-coating method using ammonium heptamolybdate tetrahydrate ((NH4 )6Mo7O244H2O ) as a single source precursor of Mo and O and. They were subjected to atmospheric heat treatment at different temperatures (200°C, 400°C and 500°C). MoO3 thin films obtained, were characterized using X-ray diffraction techniques (XRD), Scanning Electron Microscopy (SEM), Energy Dispersed Spectroscopy (EDS) and integrating sphere. The XRD patterns of annealed films show the formation of ΜοΟ3 in a polycrystalline phase, formation of MoO3 was also confirmed by EDS. The SEM photographs show that the thin films obtained are in layer-type structure and their grains size increases with increasing of annealing temperatures. The measurement results of integrating sphere show that the MoO3 thin film prepared at 500°C transmit about 72% and reflect about 12% of the visible spectrum.