A thermionic energy converter with a molybdenum-alumina cermet emitter

A study is made of the properties of cermets as electrode materials for thermionic energy converters. For thermodynamic reasons it is expected that all cermets composed of pure Mo and refractory oxides have the same bare work function. From data on the work function of Mo in an oxygen atmosphere this bare work function is estimated to be F=4.9 eV (at T=1400¿°C). Experimentally, the bare work function of Al2O3-Mo cermets was found to be F=4.5 eV, independent of the relative amounts of Al2O3 and Mo. The cesiated work function of the Al2O3-Mo cermets was found to be 0.15 eV lower than the cesiated work function of pure Mo. The bare work function of Mo3Al was found to be F=4.0 eV. The cesiated work function of Mo3Al at collector temperature conditions was 0.3 eV lower than the cesiated work function of pure Mo. The electrical power density of a diode with an Al2O3-Mo cermet emitter was 0.4 W/cm2 at 1300¿°C. The barrier index at this temperature was 2.36 V. The high barrier index is attributed to a high plasma voltage drop Vd=0.91 V

ПРОИЗВОДИТЕЛЬНОСТЬ ПРЯМОТОЧНОГО ВИБРОПНЕВМАТИЧЕСКОГО СЕПАРАТОРА ЗЕРНОВОЙ СМЕСИ

Crop yield greatly depends on quality and biological value of seeds. And biological value of seeds is characterized here not as much by geometric parameters as by their density, which is related to ripeness and nature of seed. Seeds with the greatest density have high germination energy, viability and, respectively, show high yield. The most efficient method for seed sorting by density is vibro-pneumatic sorting in a fluidized bed. Based on the studies carried out, the design and engineering layout of a direct-flow vibro-pneumatic separator with new engineering solutions has been scientifically substantiated and practically implemented. To study the process of seed sorting in a fluidized bed, a test rig was designed and manufactured, with the main element of developed direct-flow vibro-pneumatic separator allowing to significantly improve the efficiency of sorting the components of grain mixture into fractions that differ in density by 10–15 %. Based on the theoretical and experimental studies carried out, a mathematical model is obtained to determine the performance of vibro-pneumatic equipment, considering physical and mechanical properties of processed seeds and design features of the equipment. Analysis of mathematical equations allowed to determine the main directions for increasing the efficiency of vibro-pneumatic sorting of grain and seeds in a fluidized bed. The obtained mathematical dependencies can be used in substantiating rational mode and constructive parameters of vibro-pneumatic equipment operation for seed sorting by density. Implementation of research results will allow forming research and engineering basis for creation of high-performance machines for pre-seeding grain and seed preparation. Урожайность сельскохозяйственных культур во многом зависит от качества семян, их биологической ценности. При этом биологическую ценность семян характеризуют не столько геометрические параметры, сколько их плотность, которая связана со спелостью и натурой семени. Семена с наибольшей плотностью обладают высокой энергией прорастания, всхожестью и, соответственно, дают высокий урожай. Наиболее эффективным методом сортирования семян по плотности является вибропневматическое сортирование в псевдоожиженном слое. На основании проведенных исследований научно обоснована и практически реализована конструктивно-технологическая схема прямоточного вибропневматического сепаратора с новыми техническими решениями. Для изучения процесса сортирования семян в псевдоожиженном слое разработан и изготовлен экспериментальный стенд, главным элементом которого является разработанный прямоточный вибропневматический сепаратор, позволяющий значительно повысить эффективность сортирования компонентов зерновой смеси на фракции, отличающиеся между собой плотностью в пределах 10–15 %. На основании проведенных теоретических и экспериментальных исследований получена математическая модель для определения производительности вибропневматического оборудования, учитывающая физико-механические свойства обрабатываемых семян и конструктивные особенности оборудования. Анализ математических уравнений позволил определить основные направления повышения эффективности процесса вибропневматического сортирования зерна и семян в псевдоожиженном слое. Полученные математические зависимости могут быть использованы при обосновании рациональных режимно-конструктивных параметров работы вибропневматического оборудования для сортирования семян по плотности. Внедрение результатов исследований позволит создать научную и техническую основу создания высокопроизводительных машин для предпосевной под- готовки зерна и семян.

ЗАКОНОМЕРНОСТИ СЛЕДООБРАЗОВАНИЯ ПРИ ВЗАИМОДЕЙСТВИИ С ПОЧВОЙ МНОГООСНОЙ ХОДОВОЙ СИСТЕМЫ МАШИННО-ТРАКТОРНЫХ АГРЕГАТОВ

Научно-технический прогресс в сельском хозяйстве сопровождается не только благоприятными, рациональными изменениями, но и отрицательными: возникает и усиливается эрозия почв, почва чрезмерно уплотняется, уменьшается содержание гумуса, идет засоление почв и т. д. В период интенсификации сельскохозяйственногопроизводства необходимо требовательно оценивать конструкцию ходовых систем сельскохозяйственных машин, работающих в растениеводстве, так как создается ситуация, когда новые машины, призванные повысить урожай, снижают плодородие почвы. Почва, являясь средой для выращивания сельскохозяйственных культур, все большей мере начинает выполнять функцию несущего основания для движителей сельскохозяйственных машин, которые оказывают на нее механическое воздействие. Наибольшее воздействие осуществляется движителями тракторов, мощность и масса которых неуклонно растет. Так, урожайность зерновых в следах тракторов снижается на 10–15 %, а корнеклубнеплодов – на 20–30 %. В статье приведены исследования, позволяющие определить закономерности накопления повторных осадок. Получены зависимости для определения деформации почвы с различными физико-механическими свойствами при различных режимах нагружения и компоновке ходовых систем машинно-тракторных агрегатов. Установлено, как влияет на глубину следа соотношение величины давления движителя на почву с пределом ее несущей способности. Полученные данные могут быть применены в качестве исходных данных для определения рациональных параметров ходовых систем.Научно-технический прогресс в сельском хозяйстве сопровождается не только благоприятными, рациональными изменениями, но и отрицательными: возникает и усиливается эрозия почв, почва чрезмерно уплотняется, уменьшается содержание гумуса, идет засоление почв и т. д. В период интенсификации сельскохозяйственногопроизводства необходимо требовательно оценивать конструкцию ходовых систем сельскохозяйственных машин, работающих в растениеводстве, так как создается ситуация, когда новые машины, призванные повысить урожай, снижают плодородие почвы. Почва, являясь средой для выращивания сельскохозяйственных культур, все большей мере начинает выполнять функцию несущего основания для движителей сельскохозяйственных машин, которые оказывают на нее механическое воздействие. Наибольшее воздействие осуществляется движителями тракторов, мощность и масса которых неуклонно растет. Так, урожайность зерновых в следах тракторов снижается на 10–15 %, а корнеклубнеплодов – на 20–30 %. В статье приведены исследования, позволяющие определить закономерности накопления повторных осадок. Получены зависимости для определения деформации почвы с различными физико-механическими свойствами при различных режимах нагружения и компоновке ходовых систем машинно-тракторных агрегатов. Установлено, как влияет на глубину следа соотношение величины давления движителя на почву с пределом ее несущей способности. Полученные данные могут быть применены в качестве исходных данных для определения рациональных параметров ходовых систем

Comparison of the In-plane Thermal and Electrical Conductivities and Transverse Pull Strengths of Various Pyrolytic Graphite Materials

Different pyrolytic graphite materials were produced varying the annealing parameters such as temperature, pressure and time. These variations should alter the product properties in a systematic way. The coefficient of in-plane thermal conductivity, C_KT, the coefficient of electrical conductivity, $\sigma$ and the pull strength S of these samples were measured. Results for the different materials and correlations are reporte

A Prediction Model to Prioritize Individuals for a SARS-CoV-2 Test Built from National Symptom Surveys

Background: The gold standard for COVID-19 diagnosis is detection of viral RNA through PCR. Due to global limitations in testing capacity, effective prioritization of individuals for testing is essential. Methods: We devised a model estimating the probability of an individual to test positive for COVID-19 based on answers to 9 simple questions that have been associated with SARS-CoV-2 infection. Our model was devised from a subsample of a national symptom survey that was answered over 2 million times in Israel in its first 2 months and a targeted survey distributed to all residents of several cities in Israel. Overall, 43,752 adults were included, from which 498 self-reported as being COVID-19 positive. Findings: Our model was validated on a held-out set of individuals from Israel where it achieved an auROC of 0.737 (CI: 0.712–0.759) and auPR of 0.144 (CI: 0.119–0.177) and demonstrated its applicability outside of Israel in an independently collected symptom survey dataset from the US, UK, and Sweden. Our analyses revealed interactions between several symptoms and age, suggesting variation in the clinical manifestation of the disease in different age groups. Conclusions: Our tool can be used online and without exposure to suspected patients, thus suggesting worldwide utility in combating COVID-19 by better directing the limited testing resources through prioritization of individuals for testing, thereby increasing the rate at which positive individuals can be identified. Moreover, individuals at high risk for a positive test result can be isolated prior to testing. Funding: E.S. is supported by the Crown Human Genome Center, Larson Charitable Foundation New Scientist Fund, Else Kroener Fresenius Foundation, White Rose International Foundation, Ben B. and Joyce E. Eisenberg Foundation, Nissenbaum Family, Marcos Pinheiro de Andrade and Vanessa Buchheim, Lady Michelle Michels, and Aliza Moussaieff and grants funded by the Minerva foundation with funding from the Federal German Ministry for Education and Research and by the European Research Council and the Israel Science Foundation. H.R. is supported by the Israeli Council for Higher Education (CHE) via the Weizmann Data Science Research Center and by a research grant from Madame Olga Klein – Astrachan

Negative parental responses to coming out and family functioning in a sample of lesbian and gay young adults

Parental responses to youths' coming out (CO) are crucial to the subsequent adjustment of children and family. The present study investigated the negative parental reaction to the disclosure of same-sex attraction and the differences between maternal and paternal responses, as reported by their homosexual daughters and sons. Participants' perceptions of their parents' reactions (evaluated through the Perceived Parental Reactions Scale, PPRS), age at coming out, gender, parental political orientation, and religiosity involvement, the family functioning (assessed through the Family Adaptability and Cohesion Evaluation Scales, FACES IV), were assessed in 164 Italian gay and lesbian young adults. Pearson correlation coefficients were calculated to assess the relation between family functioning and parental reaction to CO. The paired sample t-test was used to compare mothers and fathers' scores on the PPRS. Hierarchical multiple regression was conducted to analyze the relevance of each variable. No differences were found between mothers and fathers in their reaction to the disclosure. The analysis showed that a negative reaction to coming out was predicted by parents' right-wing political conservatism, strong religious beliefs, and higher scores in the scales Rigid and Enmeshed. Findings confirm that a negative parental reaction is the result of poor family resources to face a stressful situation and a strong belief in traditional values. These results have important implications in both clinical and social fields

Jewish Immigrants in Israel: Disintegration Within Integration?

In her chapter, ‘Disintegration within integration’, Amandine Desille examines more recent transformations of Israel’s Law of Return – the Israeli immigration policy which provides the (imagined) repatriation of Diaspora Jews to Israel – in a context of liberalisation of the Israeli economy and the devolution of power to local authorities. Today, new immigrants follow two paths of ‘integration’: ‘direct absorp-tion’, where immigrants are granted benefits while being free to settle wherever they find fit; and ‘community absorption’, where immigrants are placed in ‘absorption centres’ and see their entitlements conditioned by residence, religious observance and more. Those two paths are ‘ethnicised’ in the sense that they depend on country of origin – Western immigrants, considered as economically useful, benefit from direct absorption and a more pluralist attitude of local governments, while immi-grants from Africa and Asia are the objects of an assimilationist policy. This situa-tion of ‘(dis)integration’ within what is supposed to be an inclusive immigrant policy for all Jews, shows the extent to which new criteria of perceived economic performance limit the integration of specific segments of newcomers. The rescaling of immigration and immigrant policies to subnational governments, although it has introduced a more multicultural approach, antagonist to the assimilationist ideology at work in Israel, has not enabled an alternative policy framework which is more accommodating to all.info:eu-repo/semantics/publishedVersio

ОГУРЦЫ ПРОДОВОЛЬСТВЕННЫЕ. ТИПОВОЙ ТЕХНОЛОГИЧЕСКИЙ ПРОЦЕСС -НОВЫЙ СТАНДАРТ ОРГАНИЗАЦИИ

The technological procedure requirements for cultivation, mechanized harvest, storage and processing of cucumber are determined.Установлены требования к выполнению технологических операций при возделывании, механизированной уборке огурца, дальнейшем хранении продукции и ее переработке

The effects of melatonin versus placebo on delirium in hip fracture patients: study protocol of a randomised, placebo-controlled, double blind trial

<p>Abstract</p> <p>Background</p> <p>With an ageing population, older persons become a larger part of the hospital population. The incidence of delirium is high in this group, and experiencing delirium has major short- and long-term sequelae, which makes prevention crucial. During delirium, a disruption of the sleep-wake cycle is frequently observed. Melatonin plays an important role in the regulation of the sleep-wake cycle, so this raised the hypothesis that alterations in the metabolism of melatonin might play an important role in the development of delirium. The aim of this article is to describe the design of a randomised, placebo controlled double-blind trial that is currently in progress and that investigates the effects of melatonin versus placebo on delirium in older, postoperative hip fracture patients.</p> <p>Methods/Design</p> <p>Acutely hospitalised patients aged 65 years or older admitted for surgical repair of hip fracture are randomised (n = 452) into a treatment or placebo group. Prophylactic treatment consists of orally administered melatonin (3 mg) at 21:00 h on five consecutive days. The primary outcome is the occurrence of delirium, to be diagnosed according to the Confusion Assessment Method, within eight days after start of the study medication. Secondary outcomes are delirium severity, measured by the Delirium Rating Scale; duration of delirium; differences in subtypes of delirium; differences in total length of hospital stay; total dose of antipsychotics and/or benzodiazepine use during delirium; and in-hospital complications. In the twelve-month follow up visit, cognitive function is measured by a Mini-Mental state examination and the Informant Questionnaire on Cognitive Decline in the Elderly. Functional status is assessed with the Katz ADL index score (patient and family version) and grip strength measurement. The outcomes of these assessments are compared to the outcomes that were obtained during admission.</p> <p>Discussion</p> <p>The proposed study will contribute to our knowledge because studies on the prophylactic treatment of delirium with long term follow up remain scarce. The results may lead to a prophylactic treatment for frail older persons at high risk for delirium that is safe, effective, and easily implementable in daily practice.</p> <p>Trial registration</p> <p>Dutch Clinical Trial Registry: <a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1576">NTR1576</a></p