Оптимизация аэродинамической формы монорельсового подвесного юнибуса

The aerodynamic optimisation of the shape of a monorail suspended unibus of string transport has been described within the study on the influence of geometric and structural elements on aerodynamic characteristics. The estimate was carried out through a comparative analysis of the features of two shapes of a model with a further change and recalculation of the model being finalised. The comparison was focused on the drag force and the shape drag coefficient. The calculations used a gas dynamics model based on the Reynolds equations using the Menter SST-k-ω (shear stress transport) turbulence model. To solve the equations to find the design functions, an upwind second-order discretisation scheme was used applying the «pressure–velocity» refinement procedure in the framework of SIMPLE algorithm of Patankar–Spalding with the ANSYS Computational Fluid Dynamics Software. The dimensions of the computational domain were chosen considering the geometric dimensions of the 3D model of the shape. Boundary conditions were identified in the solver. The simulation was carried out for the case of motion of a vehicle at a constant speed.The calculations have shown the importance and influence of the geometry of the transition sections of the vehicle body, the mandatory use of wheel fairings and the advantages of the S-shaped tail. The proposed design optimisation made it possible to reduce the drag force and coefficient by 16,9 %. The studies have resulted in selection of the optimal vehicle model which has the lowest aerodynamic drag coefficient, which made it possible to improve the energy efficiency of the system and its environmental friendliness, and consequently, the profit potential of the transportation process.В статье описана аэродинамическая оптимизация формы монорельсового подвесного юнибуса струнного транспорта. Изучалось влияние геометрических и конструктивных элементов на аэродинамические характеристики. Оценка выполнялась в сравнительном анализе показателей двух форм с дальнейшим изменением и перерасчётом дорабатываемой модели, сравнивались в первую очередь сила лобового сопротивления и коэффициент сопротивления формы. В расчётах применялась модель газовой динамики на основе уравнений Рейнольдса с использованием SST-k-ωмодели переноса сдвиговых напряжений Ментера. Для решения уравнений с целью нахождения искомых функций использовалась противопоточная схема дискретизации второго порядка с применением процедуры уточнения «давление–скорость» в рамках алгоритма SIMPLE Патанкара–Сполдинга; использовался программно-вычислительный комплекс ANSYS Fluid Dynamics. Размеры расчётной области были выбраны с учётом геометрических размеров 3D-модели формы. Идентификация граничных условий производилась в решателе. Моделирование выполнялось для случая движения транспорта с постоянной скоростью.Расчёты показали важность и влияние геометрии переходных участков корпуса транспортного средства, обязательность применения колёсных обтекателей и преимущества S-образного хвостовика. Предложенная оптимизация конструкции позволила на 16,9 % снизить силу и коэффициент аэродинамического сопротивления. По результатам проведённых исследований была выбрана оптимальная модель транспортного средства, обладающая наименьшим коэффициентом аэродинамического сопротивления, что позволило улучшить энергетическую экономичность системы и повысить её экологичность, как следствие – увеличить потенциальную рентабельность перевозочного процесса

Controlled Transformation of Electrical, Magnetic and Optical Material Properties by Ion Beams

Key circumstance of radical progress for technology of XXI century is the development of a technique which provides controllable producing three-dimensional patterns incorporating regions of nanometer sizes and required physical and chemical properties. Our paper for the first time proposes the method of purposeful direct transformation of the most important substance physical properties, such as electrical, magnetic, optical and others by controllable modification of solid state atomic constitution. The basis of the new technology is discovered by us effect of selective atom removing out of thin di- and polyatomic films by beams of accelerated particles. Potentials of that technique have been investigated and confirmed by our numerous experiments. It has been shown, particularly, that selective atom removing allows to transform in a controllable way insulators into metals, non-magnetics into magnetics, to change radically optical features and some other properties of materials. The opportunity to remove selectively atoms of a certain sort out of solid state compounds is, as such, of great interest in creating technology associated primarily with needs of nanoelectronics as well as many other "nano-problems" of XXI century.Comment: 22 pages, PDF, 9 figure

Arterial baroreceptor reflex counteracts long-term blood pressure increase in the rat model of renovascular hypertension.

INTRODUCTION: The present study tested the hypothesis that long-term effects of baroreceptor activation might contribute to the prevention of persistent arterial blood pressure (BP) increase in the rat model of renovascular hypertension (HTN). METHODS: Repetitive arterial baroreflex (BR) testing was performed in normo- and hypertensive rats. The relationship between initial arterial BR sensitivity and severity of subsequently induced two-kidney one-clip (2K1C) renovascular HTN was studied in Wistar rats. Additionally, the time course of changes in systolic BP (SBP) and cardiac beat-to-beat (RR) interval was studied for 8 weeks after the induction of 2K1C renovascular HTN in the rats with and without sinoaortic denervation (SAD). In a separate experimental series, cervical sympathetic nerve activity (cSNA) was assessed in controls, 2K1C rats, WKY rats, and SHR. RESULTS: The inverse correlation between arterial BR sensitivity and BP was observed in the hypertensive rats during repetitive arterial BR testing. The animals with greater initial arterial BR sensitivity developed lower BP values after renal artery clipping than those with lower initial arterial BR sensitivity. BP elevation during the first 8 weeks of renal artery clipping in 2K1C rats was associated with decreased sensitivity of arterial BR. Although SAD itself resulted only in greater BP variability but not in persistent BP rise, the subsequent renal artery clipping invariably resulted in the development of sustained HTN. The time to onset of HTN was found to be shorter in the rats with SAD than in those with intact baroreceptors. cSNA was significantly greater in the 2K1C rats than in controls. CONCLUSIONS: Arterial BR appears to be an important mechanism of long-term regulation of BP, and is believed to be involved in the prevention of BP rise in the rat model of renovascular HTN

Cervical sympathetic nerve activity (left) and integrated electrical activity of cervical sympathetic nerve (right).

<p>A: Normotensive Wistar rats (n = 6). B: Wistar rats with two-kidney one-clip renovascular hypertension (n = 6). C: Wistar-Kyoto rats (n = 6). D: Spontaneously hypertensive rats (n = 7).</p

Systolic blood pressure and cardiac beat-to-beat interval over 8 weeks after left renal artery clipping in Wistar rats.

*<p><i>p</i><0.05 versus controls.</p