Uranium stripping from tri-n-butyl phosphate by hydrogen peroxide solutions

The processes of uranium stripping from 30% tri-n-butyl phosphate (TBP) in "odorless" kerosene by H2O2 solutions both with and without NH4OH added were investigated in the temperature range of 20-50 C and with a volumetric ratio of 1 between the organic and aqueous phases. The uranium was selectively precipitated in the form of uranium peroxide during stripping from the organic phase by hydrogen peroxide. The stripping of uranium increased with increasing H2O2 content, increasing temperature and increasing concentration of NH3 in the range of 0-15 g/L. The use of a heated solution (40 C) that contained 4 mol H 2O2/mol U and NH3 12 g/L resulted in 99.7% of the uranium being stripped from TBP in the form of uranium peroxide. The uranium peroxide obtained by stripping is a highly pure product that exists in two different hydrated forms: UO4в̂™4H2O (92 mass %) and UO4в̂™2H2O. The mean particle diameter was 20.75 μm. The effect of hydrogen peroxide on the organic phase was studied by IR spectroscopy. No structural changes in TBP were observed after 30 cycles of extraction/stripping; thus, the use of hydrogen peroxide in this application is unrestricted. © 2013 Elsevier B.V

Rhizobacteria Effect on Arsenic Migration and Translocation of Biogenic Elements in Plants

The study was aimed at the transformation of arsenic compounds in the rhizosphere, its accumulation in plants, P and Si translocation to plants under the influence of Bacillus megaterium var. phosphaticum, and Bacillus mucilaginosus with various forms of As compounds in the soil. The authors describe the maximum effect of Bacillus megaterium var. Phosphaticum strain on As migration, its mobilization and immobilization in the rhizosphere due to arsenic leaching from mineral and difficult-todestroy compounds and its accumulation in plants. The forms of arsenic compounds were isolated from the rhizosphere based on sequential extraction procedures. The features of the inter-element As-P interaction in plants were established. With the intense accumulation of As in the rhizosphere inoculated with rhizobacteria, the intake of phosphorus into plants was not observed, as contrary to Si. The study of As and biogenic elements behavior under the influence of rhizobacteria is of great importance in the development of ecobiotechnologies related to soil remediation and crop production

Alpha Channeling in a Rotating Plasma

The wave-particle alpha-channeling effect is generalized to include rotating plasma. Specifically, radio frequency waves can resonate with alpha particles in a mirror machine with ExB rotation to diffuse the alpha particles along constrained paths in phase space. Of major interest is that the alpha-particle energy, in addition to amplifying the RF waves, can directly enhance the rotation energy which in turn provides additional plasma confinement in centrifugal fusion reactors. An ancillary benefit is the rapid removal of alpha particles, which increases the fusion reactivity.Comment: 4 pages and 3 figure

Определение коэффициента Пуассона и модуля Юнга внешней плодовой оболочки зерна кукурузы

The paper highlights the need of reducing damage caused to corn grain during cobs threshing. The damage to the grain fruit shell can be eliminated by introducing limiting conditions and ensuring optimal parameters for the threshing and separating device operation. It has been confi rmed that the patterns of corn cobs threshing can be adequately described by applying the Hertzian elastic contact theory. (Research purpose) To obtain the Poisson's ratio and Young's modulus of the fruit shell of corn grain, whose surface is in direct contact with the working bodies of the threshing device. (Materials and methods) One-factor-ata- time experiments were conducted with the subsequent statistical processing of the data array. Poisson's ratio was experimentally studied for the fruit shell of dent corn and so was Young's modulus for the grain of fl int corn, dent corn, sugar corn and popcorn. (Results and discussion) Research methods and experimental equipment have been developed to determine the Poisson's ratio and Young's modulus of the fruit shell of corn grain. It was established that with a confi dence probability of 0.95, the average Poisson's ratio value of the fruit shell of the dent corn grain equals 0.356. Young's modulus was obtained by the following corn varieties: fl int corn – 98-125 megapascals, dent corn – 78-127 megapascals, sugar corn – 97-124 megapascals, popcorn – 127-169 megapascals. It was found out that the maximum permissible speed mode of threshing can be provided if the speed of contact interaction between the grain and the threshing device pin does not exceed 1.6 meters per second. (Conclusion). It was proved that for a more comprehensive application of the Hertzian elastic contact theory when modeling the processes of threshing corn cobs, it is necessary to know the Poisson's ratio and Young's modulus for the outer fruit shell of grain. The obtained numerical values of these mechanical and technological characteristics are recommended to be used in modeling the deformation processes that regulate the threshing speed regimes.Отметили необходимость снижения травмирования зерна кукурузы при обмолоте початков. Показали, что можно ввести ограничивающие условия и обеспечить рациональные параметры при работе молотильно-сепарирующих устройств, исключающие повреждение внешней плодовой оболочки зерна. Подтвердили, что закономерности обмолота початков кукурузы адекватно описываются посредством применения контактной задачи теории упругости Г. Герца. (Цель исследования) Определить коэффициент Пуассона и модуль Юнга плодовой оболочки зерна кукурузы, поверхность которой непосредственно контактирует с рабочими органами молотильного устройства. (Материалы и методы) Использовали методы однофакторного экспериментального исследования с последующей статистической обработкой массива данных. Экспериментально изучили коэффициент Пуассона для внешней плодовой оболочки зубовидной кукурузы и модуль Юнга применительно к зерну кремнистой, зубовидной, сахарной и лопающейся кукурузы. (Результаты и обсуждение) Разработали методики исследования и экспериментальные установки для определения коэффициента Пуассона и модуля Юнга плодовой оболочки зерна кукурузы. Установили, что с доверительной вероятностью 0,95 среднее значение коэффициента Пуассона плодовой оболочки зерна зубовидной кукурузы составляет 0,356. Определили модуль Юнга применительно к нескольким разновидностям кукурузы: кремнистой – 98-125 мегапаскалей, зубовидной кукурузы – 78-127, сахарной – 97-124, лопающейся – 127-169 мегапаскалей. Выявили, что максимально допустимый скоростной режим обмолота обеспечивается при скорости контактного взаимодействия зерна и шипа молотильного устройства не более 1,6 метра в секунду. (Выводы) Доказали, что для более полного прикладного применения контактной задачи теории упругости Г. Герца при моделировании процессов обмолота початков кукурузы необходимо знать коэффициент Пуассона и модуль Юнга внешней плодовой оболочки зерна. Рекомендовали использовать полученные численные значения данных механико-технологических характеристик при моделировании деформационных процессов, регламентирующих скоростные режимы обмолота

Молотильно-сепарирующее устройство для первичного семеноводства кукурузы

The development of domestic primary maize seed production requires the development of new threshing devices capable to minimize seed grains macro- and microdamage. (Research purpose) To justify the design and technological parameters of the axial-rotary threshing and separating device for varietal and hybrid maize with a device that ensures the cobs orientation in space before threshing and partial violation of their grain structure by friction during swirling by air flow. (Materials and methods) The authors used system analysis methods, ensuring the principle of flow in mechanized lines, building algorithms for the automated systems operation and designing agricultural machines. (Results and discussion) To minimize corn grain damage, the authors recommended the sequence of technological process operations of threshing with an axial-rotary threshing-separating device, into which the cobs were fed in a strictly oriented spatial position with a partially broken grain structure. They improved the orienting- dispensing loading device, presented in the form of a vortex orienting dispenser equipped with an automatic loading level control system. The authors established the design parameters of the vortex orienting batcher based on the experimental determination of the corn cobs mechanical and technological parameters. They proposed methods, equipment and devices for determining the angle of corn cobs repose. The authors calculated the dimensional parameters of the funnel window for the corn cob output and the metering vortex tube diameter. (Conclusions) The authors developed the design of a threshing-separating device with a device for orienting corn cobs in space before threshing and partial violation of their grain structure by friction during swirling by an air stream. They determined the funnel window optimal parameters at the bottom of the vortex orienting batcher: length – 0.378 meters, width – 0.122 meters, vortex tube diameter – at least 0.624 meters.Развитие отечественного первичного семеноводства кукурузы требует разработки новых обмолачивающих устройств, способных минимизировать макрои микроповреждения семенного зерна. (Цель исследования) Обосновать конструктивно-технологические параметры аксиально-роторного молотильно-сепарирующего устройства для сортовой и гибридной кукурузы с приспособлением, обеспечивающим ориентирование початков в пространстве перед обмолотом и частичное нарушение их зерновой структуры посредством трения при вихревом перемещении воздушным потоком. (Материалы и методы) Использовали методы системного анализа, обеспечения принципа поточности в механизированных линиях, построения алгоритмов работы автоматизированных систем и конструирования сельскохозяйственных машин. (Результаты и обсуждения) Для минимизации повреждений зерна кукурузы рекомендовали последовательность операций технологического процесса обмолота аксиально-роторным молотильно-сепарирующим устройством, в которое початки подаются в строго сориентированном пространственном положении с частично нарушенной зерновой структурой. Усовершенствовали ориентирующе-дозирующее загрузочное приспособление, представленное в виде вихревого ориентирующего дозатора, оснащенного автоматической системой управления уровнем загрузки. Установили конструктивные параметры вихревого ориентирующего дозатора на основе экспериментального определения механико-технологических параметров початков кукурузы. Предложили методику, оборудование и приспособления для определения угла естественного откоса початков кукурузы. Рассчитали размерные параметры окна-воронки для вывода початков и диаметра вихревой трубы дозатора. (Выводы) Разработали конструкцию молотильного-сепарирующего устройства с приспособлением для ориентирования початков в пространстве перед обмолотом и частичным нарушением их зерновой структуры посредством трения при вихревом перемещении воздушным потоком. Определили, оптимальные параметры окна-воронки в дне вихревого ориентирующего дозатора: длина – 0,378 метра, ширина – 0,122 метра, диаметр вихревой трубы – не менее 0,624 метра

The Role of Attention in Ambiguous Reversals of Structure-From-Motion

Multiple dots moving independently back and forth on a flat screen induce a compelling illusion of a sphere rotating in depth (structure-from-motion). If all dots simultaneously reverse their direction of motion, two perceptual outcomes are possible: either the illusory rotation reverses as well (and the illusory depth of each dot is maintained), or the illusory rotation is maintained (but the illusory depth of each dot reverses). We investigated the role of attention in these ambiguous reversals. Greater availability of attention – as manipulated with a concurrent task or inferred from eye movement statistics – shifted the balance in favor of reversing illusory rotation (rather than depth). On the other hand, volitional control over illusory reversals was limited and did not depend on tracking individual dots during the direction reversal. Finally, display properties strongly influenced ambiguous reversals. Any asymmetries between ‘front’ and ‘back’ surfaces – created either on purpose by coloring or accidentally by random dot placement – also shifted the balance in favor of reversing illusory rotation (rather than depth). We conclude that the outcome of ambiguous reversals depends on attention, specifically on attention to the illusory sphere and its surface irregularities, but not on attentive tracking of individual surface dots

Multi-Timescale Perceptual History Resolves Visual Ambiguity

When visual input is inconclusive, does previous experience aid the visual system in attaining an accurate perceptual interpretation? Prolonged viewing of a visually ambiguous stimulus causes perception to alternate between conflicting interpretations. When viewed intermittently, however, ambiguous stimuli tend to evoke the same percept on many consecutive presentations. This perceptual stabilization has been suggested to reflect persistence of the most recent percept throughout the blank that separates two presentations. Here we show that the memory trace that causes stabilization reflects not just the latest percept, but perception during a much longer period. That is, the choice between competing percepts at stimulus reappearance is determined by an elaborate history of prior perception. Specifically, we demonstrate a seconds-long influence of the latest percept, as well as a more persistent influence based on the relative proportion of dominance during a preceding period of at least one minute. In case short-term perceptual history and long-term perceptual history are opposed (because perception has recently switched after prolonged stabilization), the long-term influence recovers after the effect of the latest percept has worn off, indicating independence between time scales. We accommodate these results by adding two positive adaptation terms, one with a short time constant and one with a long time constant, to a standard model of perceptual switching

Interaction of perceptual grouping and crossmodal temporal capture in tactile apparent-motion

Previous studies have shown that in tasks requiring participants to report the direction of apparent motion, task-irrelevant mono-beeps can "capture'' visual motion perception when the beeps occur temporally close to the visual stimuli. However, the contributions of the relative timing of multimodal events and the event structure, modulating uni- and/or crossmodal perceptual grouping, remain unclear. To examine this question and extend the investigation to the tactile modality, the current experiments presented tactile two-tap apparent-motion streams, with an SOA of 400 ms between successive, left-/right-hand middle-finger taps, accompanied by task-irrelevant, non-spatial auditory stimuli. The streams were shown for 90 seconds, and participants' task was to continuously report the perceived (left-or rightward) direction of tactile motion. In Experiment 1, each tactile stimulus was paired with an auditory beep, though odd-numbered taps were paired with an asynchronous beep, with audiotactile SOAs ranging from -75 ms to 75 ms. Perceived direction of tactile motion varied systematically with audiotactile SOA, indicative of a temporal-capture effect. In Experiment 2, two audiotactile SOAs-one short (75 ms), one long (325 ms)-were compared. The long-SOA condition preserved the crossmodal event structure (so the temporal-capture dynamics should have been similar to that in Experiment 1), but both beeps now occurred temporally close to the taps on one side (even-numbered taps). The two SOAs were found to produce opposite modulations of apparent motion, indicative of an influence of crossmodal grouping. In Experiment 3, only odd-numbered, but not even-numbered, taps were paired with auditory beeps. This abolished the temporal-capture effect and, instead, a dominant percept of apparent motion from the audiotactile side to the tactile-only side was observed independently of the SOA variation. These findings suggest that asymmetric crossmodal grouping leads to an attentional modulation of apparent motion, which inhibits crossmodal temporal-capture effects