322 research outputs found
AC-driven quantum spins: resonant enhancement of transverse DC magnetization
We consider s=1/2 spins in the presence of a constant magnetic field in
z-direction and an AC magnetic field in the x-z plane. A nonzero DC
magnetization component in y direction is a result of broken symmetries. A
pairwise interaction between two spins is shown to resonantly increase the
induced magnetization by one order of magnitude. We discuss the mechanism of
this enhancement, which is due to additional avoided crossings in the level
structure of the system.Comment: 7 pages, 7 figure
The study of inhibiting structural material corrosion in water recycling systems by sodium hydroxide
Influence of sodium hydroxide on the rate and nature of corrosion of St3 carbon steel and SCh 18-36 grey cast iron in highly mineralized recycling water was studied. The nature of the corrosion damage was determined and the weight index of corrosion of these alloys was calculated. By means of polarization measurements, the electrochemical indices of anodic processes on steel and cast iron were determined. The effect of the circulating water pH on behavior of steel and cast iron under anodic polarization has been studied by cyclic voltammetry. It has been shown that the effective impact of pH on characteristics of the anode processes occured at pH≥11.4. At these pH values, the metal steady-state potential shifted to a region of positive values which was an indication of inhibition of the anodic process itself. At pH≥11.4, the pitting potential significantly shifted to the positive side: the process of healing pits was faster than their formation. It has been established that steel and especially cast iron tend to pass into a passive state at pH> 10. The corrosion rate values did not exceed this index for the studied alloys in distilled water and were in the range of acceptable values. Thus, it is possible to effectively inhibit the rate of steel and cast iron corrosion, especially in the waterline zone by shifting the pH of the circulating water to the alkaline region. As a result of the conducted studies, optimal working conditions for iron alloys as the most technically important structural materials for designing closed cycles of circulating water supply systems have been established
Neutron emissions in brittle rocks during compression tests: Monotonic vs cyclic loading
Neutron emission measurements, by means of 3He devices and neutron bubble detectors, were performed during two different kinds of compression tests on brittle rocks: (i) under displacement control, and (ii) under cyclic loading. The material used for the tests was Green Luserna Granite, with different specimen sizes and shapes, and consequently with different brittleness numbers. Since the analyzed material contains iron, our conjecture is that piezonuclear reactions involving fission of iron into aluminum, or into magnesium and silicon, should have occurred during compression damage and failure. Some studies have been already conducted on the different forms of energy emitted during the failure of brittle materials. They are based on the signals captured by acoustic emission measurement systems, or on the detection of electromagnetic charge. On the other hand, piezonuclear neutron emissions from very brittle rock specimens in compression have been discovered only very recently. In this paper, the authors analyse this phenomenon from an experimental point of vie
INTELLIGENT SYSTEM OF TRAFIC LIGHT CONTROL WITH DYNAMIC CHANGE PHASES OF TRAFFIC FLOWS ON UNCONTROLLED INTERSECTIONS
There was method of making an effective system of traffic-light control of the traffic through the intersections in one direction according to which the phase coefficients for each cycle of traffic-light control are computed in real-time using the data of traffic intensity detected by transport detectors. Thus, the built-in traffic control system will be dynamically adapted to the change in the intensity of traffic flows, and the structure of the cycle and its duration will be changed taking into account the parameters of the traffic flow at the intersection. Accordingly, the traffic light cycle, where each cycle has the minimum required duration, will be most effective and will ensure uninterrupted traffic, the lack of traffic jams and the convenience for the pedestrian crossings.There was method of making an effective system of traffic-light control of the traffic through the intersections in one direction according to which the phase coefficients for each cycle of traffic-light control are computed in real-time using the data of traffic intensity detected by transport detectors. Thus, the built-in traffic control system will be dynamically adapted to the change in the intensity of traffic flows, and the structure of the cycle and its duration will be changed taking into account the parameters of the traffic flow at the intersection. Accordingly, the traffic light cycle, where each cycle has the minimum required duration, will be most effective and will ensure uninterrupted traffic, the lack of traffic jams and the convenience for the pedestrian crossings
Mobilization of plant genetic resources from the territory of Astrakhan Province, Russia
Background. The vegetation in Astrakhan Province has for a long time attracted the interest of natural scientists. However, due to inaccessibility of a number of habitats and ‘landscape fluidity’ in the Volga-Akhtuba floodplain and the Volga estuary, not all of its areas have been explored comprehensively enough. The local vast resources of useful plants of arid steppes and deserts, including crop wild relatives (CWR), have until now remained unused. Studying and mobilizing valuable plant samples, forms and species from natural communities would help to preserve the bioresources of desertified steppes and deserts, and enhance their utilization in arid areas.Methods. The collecting mission’s route passed through Chernoyarsky, Yenotaevsky, Narimanovsky, Krasnoyarsky, Kharabalinsky, Akhtubinsky, Privolzhsky, Kamyzyaksky, Limansky and Ikryaninsky districts of Astrakhan Province. With the itinerary-based method of surveying, the explorations were carried out from August 12 through August 30, 2017. The length of the route was 2,467 km. Coordinates of the collecting sites and altitudes above sea level were identified with a Garmin etrex 20x navigation device.Results. The diversity of CWR and landraces was explored in various natural ecosystems of the Volga river basin. Sixty-eight phytocenoses were described, and 160 seed samples of 39 plant species (25 genera) were collected, representing old landraces and wild relatives of fodder, fruit, cereal, vegetable and fiber crops. Many of the collected plant forms and populations with valuable biological traits deserve to be included in introduction trials and breeding programs, especially those that may serve as sources of heat, drought and salt tolerance
Stakeholders’ positioning in the projects’ implementation
Today, most people are talking about project activities and their effectiveness. Among the aspects considered in project management, there is no management of stakeholders, although their influence and participation determine the success of the project. Positioning is an important stage in project management, because it is the correct distribution of stakeholders into groups that makes it possible to build the right strategy for interacting with t stakeholders and minimize their negative impact on the project. There are several approaches to stakeholder positioning in the scientific literature, but they are not always used in practice. This decision is due to distrust of the positioning stakeholders’ process, possible mistakes in decision-making and the lack of a program to help the project manager. The article presents a way to improve the process of positioning stakeholders by creating a desktop application. Such application was developed by the authors of the article through one of the most popular programming languages Python and the well-known PyQt5 framework. As a result of using the application, the project manager receives a completed matrix where stakeholders are located on the basis of the completed information, and the opportunity to get the most out of working with stakeholders
Analysis of disturbing forces reasons provoken the recirculation pipelines enhanced vibration of sprinkler system of NPP’power unit
Розглянуті і проаналізовані причини та природа виникнення вібрації трубопроводів спринклерної системи енергоблоків АЕС. Виконано гідродинамічний розрахунок дросельної шайби трубопроводу рециркуляції, встановлені основні параметри системи рециркуляції. Запропоновані міри для усунення вібрації шляхом ліквідації умов для виникнення кавітації за місцем постановки дроселюючих пристроїв.Large local overfall of pressure, in regulative organs and, especially, in the throttling devices can be accompanied by the unstationary processes related to pulsations of static and complete pressures. These processes are not studied with necessary plenitude and can create dangerous revolting forces excitanting resonance vibrations of pipelines. Indignations can arise up: in the areas of local stream tearing, because of unstationary of stream behind throttling device and by reason of «cork» character of flow. The calculation analysis of liquid expiration through the throttle puck of d₀=0,0478[m] diameter shows that this device in combination with the special form of opening edge and set temperature of liquid t = 150C, are formed conditions, at which speed of stream in the output section increases considerably, that conduces to considerable falling of static pressure behind throttling device up to pressure below pressure of satiation at this temperature. The analysis of changing of the internal diameter influence is executed within the limits of 0,03 to 0,1 [m] on character and parameters of stream motion behind throttling device at the same initial parameters. The results of calculation researches were confirmed by experimental researches on the specially developed unit. On the working area of unit scale models were set: standard and alternative throttling devices, and also throttling device as the perforated flag (grates). On the basis of the got results of researches, three variants of technical decisions of defence from destroying dynamic influence of throttling stream as impermissible vibration of pipelines are developed and grounded.Срабатывание больших перепадов давлений на местных сопротивлениях, представляющих собой регулирующие органы и, особенно, в дросселирующих устройствах (ДУ) может сопровождаться нестационарными процессами, связанными с пульсациями статического и полного давлений. Эти процессы не изучены с необходимой полнотой и могут создавать опасные возмущающие силы, возбуждающие резонансные колебания трубопроводов. Возмущения могут возникать: в областях локальных отрывов потока в области ДУ, вследствие нестационарности струи за ДУ и по причине «пробкового» характера течения за ДУ. Расчетный анализ истечения жидкости через дроссельную шайбу (ДШ) d₀=0,0478[м] показывает, что данный диаметр ДШ в сочетании с формой кромки отверстия и заданной температурой жидкости t = 150 ºС, формируют условия, при которых значительно возрастает скорость потока в выходном сечении ДШ, что ведёт к значительному падению статического давления за ДШ вплоть до давления ниже давления насыщения при данной температуре. Выполнен анализ влияния изменения внутреннего диаметра ДШ в пределах от 0,03 до 0,1 [м] на характер и параметры движения потока после ДШ при сохранении исходных начальных параметров. Результаты расчётных исследований были подтверждены экспериментальными исследованиями на специально разработанном стенде. На рабочем участке стенда устанавливались масштабные модели: стандартной и альтернативных ДШ, а также ДУ в виде перфорированной плиты (решётки). На основании полученных результатов исследований разработаны и обоснованы три варианта технических решений по защите от разрушающего динамического воздействия дросселируемого потока в виде недопустимой вибрации трубопроводов
Applied bachelor degree programme as the direction of mobile social teachers training in the conditions of professional and mobile practice
The relevance is caused by the need to train mobile social teachers with a high level of adaptation to the changing working conditions and capable timely, reasonably, optimally and quickly to solve social and pedagogical problems of people of different age and social categories. The purpose of the article is in defining the role of applied bachelor degree in training of mobile social teachers in the conditions of professional - mobile practice. The leading method is comparative analysis of social teachers training in the conditions of state educational standard of 2005 and new generation standard FGOS-2010. The article presents the method of projects as the leading kind of activity of practice-oriented training in the direction of applied bachelor degree of future social teachers in the conditions of practice. The method of project activity can be realized in training of specialists in different direction of training and profile. © 2019 by the authors
COSEISMIC EFFECTS OF THE 11 JANUARY 2021 HOVSGOL, MONGOLIA, EARTHQUAKE
The research provides an example of the GPS time series processing for monitoring of horizontal coseismic displacements during the 11 January 2021 M 6.7 Hovsgol earthquake, Mongolia. There has been developed a methodological approach to the study of coseismic displacements at the time of the earthquake. This paper presents the results of determining the values of horizontal coseismic displacements which are 0.6 mm in the junction zone between the Hovsgol and Tunka depressions and hundredths of a millimeter for the Siberian block and Transbaikalia areas. For stations located on the southern margin of the Siberian block and stations in Transbaikalia, the vectors of coseismic displacements are directed to the west. The calculated displacement vectors of the stations near the epicenter (MNDY and BADG) are directed to the southeast
Surgery of atherosclerotic disease of carotid arteries in patients receiving substitutive therapy for chronic renal failure
Spitalul Mariinski, St.Petersburg, Rusia, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Complicaţiile cardiovasculare sunt cauza principală a mortalității la pacienţii aflaţi sub tratament substitutiv al
insuficienţei renale cronice. În acest grup de bolnavi riscul dezvoltării aterosclerozei este foarte înalt – de 10-20 ori mai mare
comparativ cu populaţia generală. Aşadar, pacienţii cu insuficienţă renală cronică trebuie să fie consideraţi un grup cu riscul cel
mai înalt de complicaţii cardiovasculare ce necesită măsuri profilactice corespunzătoare. Rata dereglărilor neurologice la
bolnavii aflaţi la tratament substitutiv al insuficienţei renale cronice oscilează între 40 şi 90% cu o mortalitate ce atinge 80-90%
în cazul ictusului. Riscul complicaţiilor chirurgiei arterelor carotide la bolnavii aflaţi la tratament substitutiv este semnificativ mai
mare decât la pacienţii fără insuficienţă renală cronică. Factorii principali cu impact negativ asupra prognosticului intervenţiei
sunt caracterul generalizat al afecţiunilor aterosclerotice, riscul major al hemoragiilor, controlul dificil al hipertensiuni i arteriale, a
dereglărilor metabolice şi electrolitice.
Material şi metode: Au fost efectuate 27 reconstrucţii carotidiene la 19 bolnavi ce se aflau sub tratament substitutiv al
insuficienţei renale cronice. La 8 bolnavi tratamentul substitutiv a fost realizat prin dializă peritoneală şi la 11 – prin hemodializă.
Rezultate: În toate cazurile stenozele hemodinamic semnificative ale arterelor carotide au fost diagnosticate prin CTangiografie
sau angiografie digitală. Stenoze asimptomatice ale arterelor carotide au fost diagnosticate la 17 bolnavi, iar 2
pacienţi au suportat în trecut un ictus ischemic. Terapia postoperatorie a fost orientată spre corecţia hipertensiunii, dereglărilor
electrolitice şi a coagulopatiei. Complicaţii perioperatorii severe: ictus ischemic sau hemoragic, hemoragie postoperatorie,
dereglări dismetabolice sau cardiace – nu au fost înregistrate.
Concluzii: Chirurgia leziunilor aterosclerotice ale arterelor carotide la pacienţii cu insuficienţă renală cronică severă reprezintă o
problema actuală şi puţin studiată. Reconstrucţiile vasculare pot preveni dezvoltarea complicaţiilor neurologice invalidizante.Introduction: Cardiovascular disorders are the leading cause of mortality among patients receiving substitutive therapy for
chronic renal failure. In this subgroup of patients the risk of development of atherosclerosis is especially high – 10-20 times
more comparing to general population. Because of this, patients with chronic renal failure should be considered as a cohort with
highest risk of cardiovascular complications which requires appropriate prophylactic measures. Rate of neurological disturbances among patients receiving substitutive therapy for chronic renal failure fluctuates from 40 to 90% with mortality
achieving 80-90% in case of stroke. The risk of complications in carotid surgery among patients receiving substitutive therapy is
significantly higher than in patients without chronic renal failure. The main factors with negative impact upon the prognosis of
intervention are generalized character of atherosclerotic lesions, high risk of bleeding, difficult control of arterial hypertension,
metabolic and electrolytic disturbances.
Material and methods: We performed 27 carotid reconstructions in 19 patients receiving substitutive therapy for chronic renal
failure. In 8 patients substitutive therapy was realized by peritoneal dialysis and in 11 patients – by hemodialysis.
Results: In all cases the significant flow limiting stenosis of carotid arteries were diagnosed on CT-angiography or digital
subtraction angiography. Asymptomatic carotid artery stenosis was diagnosed in 17 patients and 2 patients suffered the
ischemic stroke in the past. Postoperative care was centered on correction of hypertension, electrolytic disturbances and
coagulopathy. The severe periprocedural complications: hemorrhagic or ischemic strokes, postoperative bleeding, dismetabolic
or cardiac disorders were not registered.
Conclusions: Surgery of atherosclerotic lesions of carotid arteries in patients with severe chronic renal failure represents the
actual and understudied issue. Vascular reconstructions can prevent the development of disabling neurological complications
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