126 research outputs found

    Room temperature ionic liquid electrolytes for redox flow batteries

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    Redox flow batteries (RFBs) usually contain aqueous or organic electrolytes. The aim of this communication is to explore the suitability of room temperature ionic liquids (RTILs) as solvents for RFBs containing metal complexes. Towards this aim, the electrochemistry of the metal acetylacetonate (acac) complexes Mn(acac)3, Cr(acac)3, and V(acac)3 was studied in imidazolium-based RTILs. The V2+/V3+, V3+/V4+, and V4+/V5+ redox couples are quasi-reversible in 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [C2C1Im][N(Tf2)]. The Mn(acac)3 and Cr(acac)3 voltammetry, on the other hand, is irreversible in [C2C1Im][N(Tf2)] at glassy carbon (GC) but the rate of the Mn2+/Mn3+ reaction increases if Au electrodes are used. Charge–discharge measure- ments show that a coulombic efficiency of 72% is achievable using a V(acac)3/[C2C1Im][N(Tf2)]/GC cell

    Methodology to optimize fluid-dynamic design in a redox cell

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    [EN] The present work is aimed at the optimization of a redox cell design. The studied redox cell consists on a device designed to convert the energy of reactants into electrical energy when a liquid electrolyte reacts at the electrode in a conventional manner. In this particular sort of cells, the two electrolytes are present and separated by a proton exchange membrane. Therefore, the flow of the electrolyte and the interaction with the membrane takes a paramount importance for the general performance of the cell. A methodology for designing the inlet part of the cell based on optimizing the uniformity of the flow and the initial position of the membrane is presented in this study. This methodology, based on the definition and optimization of several parameters related to the electrolyte flow in different regions of the geometry, is depicted. The CFD (Computational Fluid Dynamics) model coupled with the statistical study pointed to several practical conclusions on how to improve the final geometry construction of the redox cell. A particular case study of redox cell is implemented in order to validate the proposed methodology[ES] El presente trabajo tiene como objetivo la optimización de un diseño de la batería redox. La pila redox estudiada consiste en un dispositivo diseñado para convertir la energía de los reactivos en energía eléctrica cuando un electrolito líquido reacciona en el electrodo de una manera convencional . En este tipo particular de células , los dos electrolitos están presentes y separados por una membrana de intercambio de protones . Por lo tanto , el flujo del electrolito y la interacción con la membrana tiene una importancia primordial para el rendimiento general de la célula . La metodología propuesta para el diseño de la parte de entrada de la celda en base a la optimización de la uniformidad del flujo y la inicial posición de la membrana se presenta en este estudio . Esta metodología, basada en la definición y optimización de varios parámetros relacionados con el flujo de electrolito en las diferentes regiones de la geometría , es representado . El modelo de CFD (Computational Fluid Dynamics ), junto con el estudio estadístico se refirió a varias conclusiones prácticas sobre la manera de mejorar la construcción geometría final de la pila redox . El estudio de caso particular de célula redox que se describe, se implementa con el fin de validar la metodología propuestaEscudero González, J.; López Jiménez, PA. (2014). Methodology to optimize fluid-dynamic design in a redox cell. Journal of Power Sources. 251(1):243-253. doi:10.1016/j.jpowsour.2013.11.058S243253251

    Using Motivational Interviewing to Improve Parent Engagement in Student Attendance Improvement Conferences

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    This dissertation in practice focused on the use of Motivational Interviewing in the school environment between school staff and families. More specifically, this program evaluation sought to see if the use of Motivational Interviewing by school staff could improve parent participation rates in student attendance improvement conferences (SAICs). Motivational Interviewing is an evidence-based practice to help people prepare for a change in behavior (Herman et al., 2014). Parents assert they would be more involved in school functions if they genuinely felt more welcomed by school personnel (Sheldon, 2007). Thus, the hypothesis of the program evaluation was that Motivational Interviewing might be a systematic strategy school personnel could use with families to improve building rapport and communication. The following questions guided this study. 1. Through professional development sessions, did staff learn the basic tenets of Motivational Interviewing techniques? 2. What content is most difficult for school staff to master? 3. Do school staff feel more confident collaborating with families after receiving training in motivational interviewing techniques? 4. Compared to prior semesters, did more families attend SAICs once training began? 5. Once trained, did staff report changes in family engagement during SAICs? Participants in this study included four school personnel who frequently communicate with families regarding student attendance. The participants completed a three-module professional development course. Participants completed pre- and post-quizzes after each module, and quiz results were analyzed for content mastery. Participants also completed surveys regarding their comfort level using Motivational Interviewing, which were analyzed for growth. The study established that all participants mastered the content taught during the professional development modules, and all participants rated growth. Findings from this small sample and the limited-scope study showed that the professional development did improve educators’ skills with Motivational Interviewing but did not necessarily improve family participation in SAICs

    Rosliny fitosanitarne w plodozmianach a zdrowotnosc i plonowanie ziemniaka

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    W pracy przedstawiono wyniki badań z lat 1997-1999 gromadzonych w ramach statycznego doświadczenia w Bałcynach k. Ostródy. Dotyczą one doboru przedplonów w specjalistycznej uprawie dwóch odmian ziemniaka: Lena - skrobiowa, nieodporna i Ibis - jadalna, odporna na mątwika ziemniaczanego. W dwóch 6-polowych płodozmianach uprawiano po dwa pola ziemniaka w 3-polowych ogniwach, z różnym doborem gatunków zbóż i roślin fitosanitarnych jako przedplonów. Średnie plony bulw obu odmian ziemniaka były zbliżone. Z roślin regenerujących groch pastewny nie odgrywał plonotwórczej roli, natomiast koniczyna czerwona zwiększyła plon bulw o 16%, w porównaniu do stanowiska po dwóch zbożach. Międzyplon - gorczyca biała, uprawiana po życie, podtrzymywała plon odmiany Lena, mimo rosnącej populacji Globodera rostochiensis Woli., a u odmiany Ibis zwiększyła go o 4,7%. Czynniki doświadczenia różnicowały dorodność roślin, strukturę bulw oraz plon skrobi. Poziom i zróżnicowanie plonów mogło wynikać z różnego porażenia roślin ziemniaka zarazą ziemniaka (Phytophthora infestans), parchem zwykłym (Streptomyces scabies), a w mniejszym stopniu rizoktoniozą (Rhizoctonia solani).Paper presents the partial results (1997-1999) of a static experiment conducted at Bałcyny, near Ostróda. The results dealt with the choice of forecrops in a specialistic cultivation of two potato cultivars: Lena - high-starch, unresistant and Ibis - edible and resistant to potato cyst nematode. In two 6-course crop rotations there were grown two fields of potato in 3-field links in each with different choice of cereal species and phytosanitary plants. The mean tuber yields of both cultivars were alike, but differentiated by chosen forecrops. Among phytosanitary crops, the fodder peas played no yield creating role, whereas red clover increased the yield by 16% as compared to the rotation position of potato after two cereals. The catch crop - white mustard, grown after winter rye held up the yield of Lena cv. in spite of growing population of Globodera rostochiensis Woll., and at Ibis cv. increased the yield by 4.7%. Experimental factors differentiated tuber structure and starch yield. The level and differentiation of yields could be influenced by late blight (Phytophthora infestans), scab (Streptomyces scabies) and to lower extent by rhizoctoniose (Rhizoctonia solani)

    Tamanho, composição e características dos Conselhos de Administração no Brasil : o caso das companhias listadas no Nível 2 e Novo Mercado

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    Este estudo apresenta o tamanho, a composição e as principais características dos Conselhos de Administração das empresas listadas no Nível 2 e no Novo Mercado, segmentos diferenciados de governança corporativa da BOVESPA. O Conselho de Administração é um dos principais mecanismos de governança corporativa nas empresas devido ao seu papel de tomador de decisões de controle, monitor dos gestores e fixador das diretrizes estratégicas organizacionais. O objetivo deste trabalho é apresentar o perfil dos Conselhos de Administração das companhias do Nível 2 e do Novo Mercado da BOVESPA. Para se conhecer a configuração do Conselho de Administração, foram levantados e analisados os dados sobre seu tamanho médio, duração média do mandato dos conselheiros, participação de familiares, executivos principais, conselheiros independentes e membros ligados ao grupo controlador além da ocorrência de board interlocking. As características levantadas foram comparadas com as recomendações dos códigos de boas práticas de governança corporativa, com o intuito de se conhecer não só o perfil dos Conselhos de Administração como sua adequação às melhores práticas. Os resultados obtidos mostram que a maioria dos órgãos estudados está de acordo com as sugestões de melhores práticas em aspectos como duração dos mandatos e tamanho do colegiado. A ocorrência de board interlocking mostrou-se uma prática comum, podendo trazer vantagens e desvantagens para as empresas. A incidência de familiares, membros da Diretoria Executiva ou ligados ao grupo controlador apareceram como componentes da composição dos Conselhos. A participação de conselheiros independentes mostrou-se apenas um pouco acima do mínimo exigido. O perfil dos Conselhos traçado mostra a necessidade de aumentar a participação de conselheiros independentes na sua configuração para que estes órgãos possam desempenhar sua função controladora e crítica da gestão com maior eficácia. Cabe às empresas buscarem cada vez mais a adesão às práticas recomendadas de boa governança, pois estas transmitem maior segurança e conforto aos investidores em relação às escolhas de suas aplicações.This study presents the size, the composition and the main characteristics of the Board of Directors of the companies listed in the Nível 2 (Level 2) and Novo Mercado (New Market) different segments of corporative governance of the BOVESPA (São Paulo Stock Exchange). The Board of Directors is one of the main mechanisms of corporative governance in the companies due to its paper of controlling decisions, monitoring the managers and fixing the strategical guidelines of the organization. The objective of this work is to present the profile of the Board of Directors of the company of Level 2 and the New Market of the BOVESPA. To know the configuration of the Board of Directors, it had been raised and analyzed the data on its average size, average duration of the mandate of the directors, participation of family members, CEOs, independent directors and members from the main financial group plus the occurrence of board interlocking. The raised characteristics had been compared with the recommendations of the good codes of practical of corporative governance, with the intention of knowing not only the profile of the Board of Directors as its adequacy to the best practices. The results show that the majority of the studied boards are in accordance with the top suggestions of practices in aspects as duration of the mandates and size of the collegiate. The occurrence of board interlocking appeared as a common practice, being bringing advantages and disadvantages to the companies. Familiar members, CEOs and members of the main financial group are elements of the composition of the board. The participation of independent members of the board is slightly above of the minimum demanded. The profile of the board shows the necessity to increase the participation of independent directors in its configuration so the boards are more able to role its critical and controller function of the managers with increased effectiveness. The adhesion to the best practice recommended by the corporate governance guides has to be searched more and more by the companies, so they can transmit greater security and comfort to the investors in relation to their choices of financial applications

    Uprawa ziemniaka w monokulturze przerywanej facelia blekitna

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    W wieloletnim doświadczeniu statycznym badano efektywność przyorywania facelii błękitnej (Phacelia tanacelifolia) jako międzyplonu ścierniskowego w płodozmianie po pszenżycie ozimym i w monokulturze jako przerywnika ciągłej uprawy ziemniaka. Wyrażono ją wielkością plonu bulw wczesnych odmian ziemniaka oraz zmianami w warstwie uprawnej gleby. W monokulturze ziemniaka średni plon nadziemnej zielonej masy facelii, corocznie przyorywanej, był ponad 2-krotnie większy niż w płodozmianie. W obu wariantach następstwa roślin średni plon bulw ziemniaka nie różnił się, natomiast zastosowane pestycydy (herbicyd, herbicyd + fungicyd) zwiększały go bardziej w płodozmianie niż w monokulturze. Wieloletnia uprawa ziemniaka w monokulturze zwiększyła zakwaszenie gleby i zubożała ją w materię organiczną, potas i bor. Ponadto obniżyła pojemność sorpcyjną i stopień wysycenia kompleksu sorpcyjnego zasadami. Corocznie przyorywana biomasa facelii wpływała pozytywnie na biologiczne i fizyko-chemiczne właściwości gleby.In a many-year field experiment the effectiveness of tancy phacelia (Phacelia tanacelifolia) as a catch crop in the rotation after winter triticale and in monoculture as an intercropping of continuous potato growing was studied. The effectiveness was expressed by tuber yields of early potato cultivars and by changes in a plough layer of the soil. In potato monoculture the mean yield of tancy phacelia green matter, ploughed under every year, was twice higher than in the rotation, owing to earlier seedings. In both variants of the crop sequence, the mean potato yield did not differ, but application of the pesticide (herbicide, herbicide + fungicide) increased the yield more in rotation than in monoculture. Continuous growing of potato increased acidity of the soil and decreased organic matter, potassium and boron contents as well as the degree of base saturation. The biomass of tancy phacelia, ploughed under every year, positively influenced biological and physicochemical properties of the soil

    Yield and chosen quality traits of oat grown in the period of conversion to organic cropping system

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    W latach 2004-2005 w Rolniczym Zakładzie Doświadczalnym w Bałcynach (53o35’ N; 19o51’ E), należącym do Uniwersytetu Warmińsko-Mazurskiego, prowadzono badania nad określeniem skutków przestawiania uprawy owsa z systemu konwencjonalnego na ekologiczny. W jednym płodozmianie uprawiano go zgodnie z zasadami rolnictwa konwencjonalnego, stosując nawozy mineralne i pestycydy. W drugim realizowano dwuletni okres przestawiania uprawy roślin na system ekologiczny. W uprawie konwencjonalnej i w obiekcie z uprawą przestawianą na ekologiczną nagoziarnistą odmianę owsa wysiewano w stanowisku po pszenicy ozimej. W płodozmianie konwencjonalnym, średnio z dwóch lat, uzyskano 4,81 t·ha-1 ziarna owsa. Przestawianie jego uprawy na ekologiczną obniżyło wydajność o 28,7%. Zmniejszeniu plonów ziarna towarzyszyło pogorszenie wszystkich elementów morfometrii roślin i struktury plonu. Zawartość białka i P w ziarnie owsa w obiekcie z uprawą przestawianą na ekologiczną była mniejsza, natomiast K i Mg – większa niż w obiekcie konwencjonalnym. Zawartość Ca w ziarnie owsa pochodzącego z obu systemów uprawy była identyczna.In the period of 2004-2005 researches were done at the Agricultural Experimental Station in Bałcyny (53o35’ N; 19o51’ E) of the University of Warmia and Mazury to determine the results of conversion of oat growing from the conventional system to the organic one. In the first crop rotation it was cultivated according to the principles of the conventional cropping system, applying mineral fertilizers and pesticides. In the second one, a two-year period of conversion of crops to the organic system was realized. In the conventional cropping and in the plot being converted to the organic one naked-grain oat cultivar was sown in the fields after winter wheat. In the conventional crop rotation, as mean from 2 years, 4.81 t∙ha-1 of oat grain was obtained. The conversion of its growing to organic system decreased the yield by 28.7%. The decrease in grain yield was accompanied by the worsening of all the morphometric elements of the crops and yield structure. The content of protein and P in oat grain in the field of cropping converted to organic system was lower, whereas the contents of K and Mg were higher than those in the field with conventional cropping. The content of Ca was identical in oat grains coming from the two cropping systems
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