2,105 research outputs found
Meeting with the Hebrew author Elias Hurwitz
No full textWhite paper; handpainted; on the reverse of Luftwaffe uniform pattern. Digitized posters are related to the activities of Jewish displaced persons drawn from the Records of Displaced Persons Camps and Centers in Germany (RG 294.2) Italy (RG 294.3) and Austria (RG 294.4) held by YIVO Archives. Please consult the historical note for those record groups for further information.Digital ImageDigital finding aid available
Obituary announcement about author and labor activist Sh. Mendelson
No full textBrown paper; handpainted. Digitized posters are related to the activities of Jewish displaced persons drawn from the Records of Displaced Persons Camps and Centers in Germany (RG 294.2) Italy (RG 294.3) and Austria (RG 294.4) held by YIVO Archives. Please consult the historical note for those record groups for further information.Digital ImageDigital finding aid available
Sweeping has no effect on renormalized turbulent viscosity
No full textWe perform renormalization group analysis (RG) of the Navier-Stokes equation in the presence of constant mean velocity field , and show that the renormalized viscosity is unaffected by , thus negating the ``sweeping effect", proposed by Kraichnan [Phys. Fluids {\bf 7}, 1723 (1964)] using random Galilean invariance. Using direct numerical simulation, we show that the correlation functions for and differ from each other, but the renormalized viscosity for the two cases are the same. Our numerical results are consistent with the RG calculations
Fertilización con K, S y Zn aumenta la producción de lotus pero no de trébol blanco en mezcla con raigrás en Corrientes = Fertilization with K, S and Zn increases yield of lotus but not of white clover in central Corrientes
No full textLa fertilización con K, S y Zn puede aumentar la producción de leguminosas en pasturas (Collins et al. 1986; Grewal et al. 2000). Corrientes presenta suelos pobres en estos nutrientes y esta técnica podría favorecer la participación de las leguminosas en verdeos y pasturas mixtas. Los objetivos del trabajo fueron: 1) determinar el efecto de la fertilización completa (P, K, S y Zn) vs fertilización fosforada en la producción de Lotus corniculatus (Lotus) y de Trifolium repens (TB) sembrados con raigrás anual (Rg), y 2) Comparar la producción de Lotus, TB y Medicago sativa (Alfalfa) sembrados con Rg y con fertilización completa.EEA MercedesFil: Barbera, Pablo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes; ArgentinaFil: Benitez, Julio Cesar. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Mercedes; Argentin
BONDING AND DYNAMICS OF CNRg AND CRg COMPLEXES
No full textAuthor Institution: Department of Chemistry, Emory University, Atlanta, GA 30322The van der Waals complexes of CN and C with rare gas atoms (Rg) are of interest from the perspectives of their bonding characteristics and predissociation dynamics. Matrix isolation data indicate that that the bonding ranges from a weak van der Waals interaction for the Ne complexes to incipient chemical bonding for Xe. The low-lying vibronic states of CN and C are interleaved, which facilitates electronic energy transfer. Consequently, electronic predissociation of CNRg and CRg complexes provides a useful means to examine the detailed dynamics of electronic energy transfer. Predissociation processes for CNRg complexes have been characterized using double resonance techniques. The final state distributions exhibit symmetry preferences that yield insights concerning the topologies of the relevant potential energy surfaces. In addition, bond energies can be deduced from the predissociation dynamics. Data for the binary complexes CNRg (Rg=Ne, Ar, Kr, and Xe) and CRg will be presented, along with theoretical analyses based on potential energy surfaces
René Géronimo Favaloro : pioneer of Cardiac Surgery
No full textDr. René G. Favaloro moved to the Cleveland Clinic in 1962 and proceeded to reshape the face of cardiac surgery as we knew it. Together with his colleagues at the Cleveland Clinic, Drs. Effler, Sones, Proudfit, Groves, Sheldon and countless others, he contributed to the double internal mammary arterymyocardial implantation by the Vineberg method, and by May 1967, he reconstructed the right coronary artery by the saphenous vein graft interposition. These landmark procedures paved the way for the aorto-coronary saphenous vein bypass graft in October 1967. Many similar breakthroughs ensued, with the application of the bypass technique to the left coronary artery, the combination of coronary artery bypass graft with left ventricular reconstruction and valve repair/replacement and finally, by December, a double bypass to the right coronary artery and anterior descending branch of the left coronary artery. In June, 1971, Dr. Favaloro decided to leave the Cleveland Clinic and return to Argentina where he created a medical centre, a teaching unit, a research department and finally an Institute of Cardiology and Cardiovascular Surgery. This was his greatest personal ambition. Over and above his brilliant mind and craft, Dr. Favaloro was a man of integrity, courage, honesty and humility, whose name will never cease to reverberate throughout the history of medicine.peer-reviewe
Robust microgrid operation under renewable generation
No full textLa generación renovable está cambiando la generación convencional en microrredes. Por lo tanto, el funcionamiento de las microrredes se está volviendo más complejo y desafiante para garantizar la estabilidad y la fiabilidad. En este artículo, presentamos un enfoque de aversión al riesgo para el funcionamiento óptimo de las microrredes en presencia de generación renovable (RG) y sistema de almacenamiento de energía de batería (BESS).Renewable generation is shifting conventional generation in microgrids. Thus, the operation of microgrids is becoming more complex and challenging for ensuring stability and reliability. In this paper, we introduce a risk-averse approach for optimal operation of microgrids in the presence of renewable generation (RG) and Battery Energy Storage System (BESS). These sources are modeled and embedded into an AC optimal convex power flow equations. A Two-Stage Adaptive Robust Optimization mathematical framework is presented to address uncertainties in the load demand and renewable resources. Uncertainty is depicted with a polyhedron instead of probability distribution function. The resulting model is a three-level min-max-min problem. The robust model is formulated to minimize the total cost of energy purchased from the distribution substation and energy cost of distributed generation. Results of an illustrative example and a case study based on the 11-node test system show the effectiveness of the proposed approach.Sarajev
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No full textSejam R um anel comutativo com unidade e G um grupo. O anel de grupo RG tem uma involução natural, *, que aplica cada elemento do grupo em seu inverso ('g IND.*' = 'G ind. -1', g pertencente a G). Esta tese é dedicada ao estudo dos elementos simétricos e anti-simétricos de RG, com respeito a involução *, cujos conjuntos denotemos por RG 'POT +' e RG 'POT -', respectivamente. Estudamos a comutatividade de RG 'POT +', isto é, sob que condições o conjunto RG 'POT +' é um subanel de RG. O estudo foi dividido em dois casos dependendo da característica de R ser diferente de 2 ou não, como acontece sempre que se trabalha com anéis com involução. Em ambos os casos caracterizamos completamente os grupos G quaisquer, tais que RG 'POT +' é comutativo. Depois estudamos a comutatividade de RG 'POT -', memso que este conjunto não forme um subanel associativo mas sim um anel não associativo, quando considerado RG com o produto de Lie [x,y] = xy - yx. Também aqui dividimos o estudo em dois casos dependendo da característica de R e damos uma caracterização completa dos grupos G tais que RG 'POT -' é comutativo. Finalmente, no capítulo III, caracterizamos os grupos G, de torção, tais que o conjunto das unidades simétricas de RG é um subgruponot availabl
Effect of magnetic dipolar interactions on nanoparticle heating efficiency: Implications for magnetic hyperthermia
No full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESMagnetic nanoparticles can generate heat when submitted to alternating magnetic fields of adequate amplitude and frequency. This phenomenon is named magnetic hyperthermia and has several therapeutic applications, as for example, in the treatment of cancer. In general, the theoretical models used to describe this neglect the effect of interparticle interaction. In this thesis we investigate the effect of magnetic dipolar interaction in the magnetothermal efficiency (named specific loss power – SLP) of bicompatible magnetic nanoparticles. Firstly, we develop a chain of magnetic particles model, where we prove that the interaction leads to a contribution to the uniaxial anisotropy. This term in the free energy density allowed us to extract from the electron magnetic resonance technique (EMR) information about the mean chain size in the colloid. Further, this additional magnetic nanoparticle anisotropy term was used to develop an analytical theoretical model that takes into account the effect of the dipolar interaction between nanoparticles to SLP, considering the case where the magnetization responds linearly to the field (Linear Response Theory). Our calculations indicate that depending on the particle parameters, specially the anisotropy, the effect can be to enhance or decrease the heat generation. Moreover, we showed that increasing the chain size (number of particles in the chain) the optimal particle size for hyperthermia can decrease up to 30% in comparison with non-interacting particles. This result has several clinical implications, which allowed us to suggest some strategies for improving the therapeutic efficacy. In order to investigate experimentally the effect, two magnetic fluids, one containing spherical nanoparticles based on manganese ferrite (MnF-citrate) in the superparamagnetic regime, and another commercial one (BNF-starch) magnetite-based with a shape of a parallellepiped and blocked, were selected and deeply characterized. We found a decrease of SLP increasing the chain size for the MnF sample, while for BNF-starch no effect was found at the same experimental conditions. The decrease of SLP in the MnF sample, within the particle concentration range, was explained considering in the model not only the effect in the anisotropy but also by an increase in the damping factor parameter, a term correlated to spin-phonon interaction. Data obtained using EMR and Monte Carlo simulations corroborate our hypothesis. The absence of concentration effect for the BNF sample was attributed to the higher anisotropy value and to the probable influence of brownian relaxation. In addition, the same chain model was used to investigate the behavior of blocked nanoparticles of Stoner-Wohlfarth type. In this case, we demonstrate that the chain formation increases the magnetic hyperthermia, as found in magnetosomes. Finally, we showed that a fluctuation of the dipolar interaction field between particles in the chain, which does not destroy the symmetry of this term, shows a Vogel-Fulcher behaviour in the weak coupling regime.Nanopartículas magnéticas são capazes de gerar calor quando submetidas a campo magnético alternado de amplitude e frequência adequadas. Este fenômeno é conhecido como magnetohipertermia e possui aplicações terapêuticas como, por exemplo, no tratamento de câncer. Em geral, os modelos teóricos que descrevem o fenômeno não levam em conta efeitos associados à interação partícula-partícula. Nesta tese investigamos o efeito da interação dipolar magnética na eficiência magnetotérmica (SLP) de nanopartículas magnéticas biocompatíveis. Primeiramente desenvolvemos um modelo de cadeia de nanopartículas magnéticas, aonde provamos que a interação entre partículas que formam uma cadeia linear equivalem a uma contribuição uniaxial a anisotropia. Essa contribuição à densidade de energia permitiu que obtivéssemos por meio da técnica de ressonância magnética eletrônica (RME) informações acerca do tamanho médio de aglomerado na suspensão coloidal. Posteriormente utilizamos esse termo adicional da anisotropia efetiva da nanopartícula para propor um modelo teórico analítico que leve em consideração o efeito de tal interação na eficiência de aquecimento de nanopartículas magnéticas em um fluido para o caso em que a magnetização das nanopartículas responde linearmente ao campo (Teoria da Resposta Linear). Nossos cálculos indicaram que, dependendo de parâmetros da nanopartícula, em particular da anisotropia, este efeito pode aumentar ou diminuir a geração de calor. Além disso, mostramos que o aumento do número de partículas formando cadeias lineares reduz o diâmetro ótimo para hipertermia em até 30% em relação ao valor esperado para partículas isoladas. Este resultado possui fortes implicações clínicas, e permitiu que sugeríssemos algumas estratégias para aumentar a eficiência terapêutica. No intuito de investigar experimentalmente este efeito, dois fluidos magnéticos, um contendo nanopartículas esféricas de ferrita de Mn (MnF-citrato) no regime superparamagnético e outra comercial (BNF-starch) à base de magnetita com forma de nanoparalelepípedos e contendo partículas bloqueadas, foram selecionados e amplamente caracterizados. Observamos uma diminuição no SLP com o aumento de partículas na cadeia para a amostra MnF-citrato, para todos os valores de campo, enquanto que para a amostra BNF-starch não percebemos alteração do SLP. O decréscimo do SLP da amostra MnF, na faixa de concentração investigada, foi explicado incluindo não apenas o efeito na anisotropia efetiva, mas também o aumento no valor do fator de amortecimento. Dados de RME e simulação de Monte Carlo corroboraram tal hipótese. A ausência de efeito para amostra BNF-starch foi atribuída à alta anisotropia e provável influência de relaxação browniana. Adicionalmente, o modelo de cadeia foi usado para explicar o comportamento de nanopartículas bloqueadas do tipo Stoner-Wohlfarth. Neste caso demonstramos que a formação de cadeias aumenta a hipertermia magnética, como verificado em magnetossomos. Finalmente, mostramos que uma flutuação no campo dipolar interpartículas na cadeia, que não destrua a simetria desta contribuição, fornece um comportamento do tipo Vogel-Fulcher no regime fracamente interagente
A non-classical synthetic strategy for organic mesocrystals
No full textMesocrystals are ordered nanoparticle superstructures, often with internal porosity, which receive much recent research interest in catalysis, energy storage, sensors, and biomedicine area. Understanding the mechanism of synthetic routes is essential for precise control of size and structure that affect the function of mesocrystals. The classical synthetic strategy of mesocrystal was formed via self-assembly of nanoparticles with a faceted inorganic core but a denser (or thicker) shell of organic molecules. However, the potential materials and synthetic handles still need to be explored to meet new applications. In this work, we develop a non-classical synthetic strategy for organic molecules, such as tetrakis (4-hydroxyphenyl) ethylene (TPE-4OH), tetrakis (4-bromophenyl) ethylene (TPE-4Br), and benzopinacole, to produce mesocrystals with composed of microrod arrays via co-solvent-induced crystal transformation. The aligned nanorods are grown epitaxially onto organic microplates, directed by small lattice mismatch between plates and rods. Thus, the present work offers general synthetic handle for establishing well-organized organic mesocrystals.Ministry of Education (MOE)Published versionThe author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This work was supported by the MOE of Singapore (RG 14/13 and RG 5/16), the National Natural Science Foundation of China (No. 21673117), recruitment Program of Global Experts, Jiangsu Provincial Foundation for Specially-Appointed Professor, start-up fund at Nanjing Tech University (39837102), SICAM Fellowship from Jiangsu National Synergetic Innovation Center for Advanced Materials, and Jiangsu Science and Technology Plan (Project No. BK20211258)
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