Theoretical simulation of the picosecond runaway-electron beam in coaxial diode filled with SF6 at atmospheric pressure

This paper presents detailed results of gas discharge theoretical simulation and the explanation of probabilistic mechanism of fast-electrons generation. Within the framework of a hybrid mathematical model, the hydrodynamic and the kinetic approaches are used simultaneously in order to describe the dynamics of different components of a low-temperature discharge plasma. The breakdown of a coaxial diode occurs in the form of a dense plasma region expanding from the cathode. On this background there is a formation of runaway electrons that are initiated by the ensemble of plasma electrons generated in the region of locally enhanced electric field within the front of the dense plasma. It is shown that the power spectrum of fast electrons in the discharge contains the group of electrons with the so-called “anomalous” energies. Comparison of the calculation results with the existent experimental data gives a good agreement for all major process parameters

Метод двойного резонанса для определения точки гелеобразования

The application of double resonance method for determining the dynamics of fluidity changes of thermotropic gel-forming compositions based on cellulose ether is considered. To determine the gel point, a modified version of the ‘Rheokinetika’ viscometer including two identical sensors and measuring cells of different diametersРассмотрено применение метода двойного резонанса для определения динамики изменения текучести термотропных гелеобразующих композиций на основе метилцеллюлозы. Для определения точки гелеобразования использован модифицированный вискозиметр «Реокинетика», содержащий два идентичных датчика и измерительные ячейки различных диаметро

Efficiency of Finding Muon Track Trigger Primitives in CMS Cathode Strip Chambers

In the CMS Experiment, muon detection in the forward direction is accomplished by cathode strip chambers~(CSC). These detectors identify muons, provide a fast muon trigger, and give a precise measurement of the muon trajectory. There are 468 six-plane CSCs in the system. The efficiency of finding muon trigger primitives (muon track segments) was studied using~36 CMS CSCs and cosmic ray muons during the Magnet Test and Cosmic Challenge~(MTCC) exercise conducted by the~CMS experiment in~2006. In contrast to earlier studies that used muon beams to illuminate a very small chamber area ($< \! 0.01$~m$^2$), results presented in this paper were obtained by many installed CSCs operating {\em in situ} over an area of $\approx \! 23$~m$^2$ as a part of the~CMS experiment. The efficiency of finding 2-dimensional trigger primitives within 6-layer chambers was found to be~$99.93 \pm 0.03\%$. These segments, found by the CSC electronics within $800$~ns after the passing of a muon through the chambers, are the input information for the Level-1 muon trigger and, also, are a necessary condition for chambers to be read out by the Data Acquisition System

Theoretical simulation of a gas breakdown initiated by external plasma source in the gap with combined metal-dielectric electrodes

This paper is devoted to the theoretical investigation of the breakdown in short discharge gaps of different geometries under the influence of the plasma stream from an external source. The structural feature is the presence of dielectric elements in the electric discharge gap area, which have high emission activity and the ability to accumulate a surface charge. The simulation was performed for a 2-D planar geometry of the discharge gap between two metal electrodes with dielectric coating surrounded by the gaseous medium. Charged particles generation and dynamics have been described by a system of partial differential equations in the diffusion-drift approximation within the two-fluid hydrodynamics plasma model. The basic advantages of the proposed model (such as a wide variety of boundary conditions and geometries of the discharge gap, the scalability of the critical parameters of the environment, and a simple representation of surface reactions) are demonstrated successfully. During computations, the range of gas pressure and the external preionization level at which the probability of low-voltage self-sustained discharge is high enough were identified

Theoretical simulation of a gas breakdown initiated by external plasma source in the gap with combined metal-dielectric electrodes

This paper is devoted to the theoretical investigation of the breakdown in short discharge gaps of different geometries under the influence of the plasma stream from an external source. The structural feature is the presence of dielectric elements in the electric discharge gap area, which have high emission activity and the ability to accumulate a surface charge. The simulation was performed for a 2-D planar geometry of the discharge gap between two metal electrodes with dielectric coating surrounded by the gaseous medium. Charged particles generation and dynamics have been described by a system of partial differential equations in the diffusion-drift approximation within the two-fluid hydrodynamics plasma model. The basic advantages of the proposed model (such as a wide variety of boundary conditions and geometries of the discharge gap, the scalability of the critical parameters of the environment, and a simple representation of surface reactions) are demonstrated successfully. During computations, the range of gas pressure and the external preionization level at which the probability of low-voltage self-sustained discharge is high enough were identified

Experimental modeling of the microalgae cultivation in a photobioreactor using manure

The article studies the experimental process of cultivation of microalgae in a photobioreactor (PBR) to study the effect of technological conditions on the productivity of microalgae. This process allows obtaining initial data for the development of closed cycles of using the energy potential of alga mass in heat and power supply of various industries, including agricultural enterprises (livestock complexes, poultry farms, etc.) The scheme of a closed cycle of power supply of the cattle complex allows obtaining hot water, feed additives to the cattle ration, bio humus, motor biofuel and carbon dioxide, which is advisable to use in the process of cultivating microalgae. The experiments were carried out on a photobioreactor for cultivating microalgae with an intelligent control system. The developed photobioreactor differs from the known ones in the pulsating hydrodynamic regime of feeding the nutrient solution, which provides an increase in the productivity of the microalgae cultivation up to 15%. The experimental model of the cultivation conditions of the microalga Ch. Vulgaris on a combined diet (Tamiya medium + manure substrate) showed a noticeable increase in crop productivity when adding cattle manure extract to the nutrient medium in an amount from 30 to 60% (vol.). This can be used in the development of closed cycles of heat and power supply for cattle farms based on biofuels of the third generation, obtained from the phytomass of microalgae

Theoretical simulation of the picosecond runaway-electron beam in coaxial diode filled with SF6 at atmospheric pressure

This paper presents detailed results of gas discharge theoretical simulation and the explanation of probabilistic mechanism of fast-electrons generation. Within the framework of a hybrid mathematical model, the hydrodynamic and the kinetic approaches are used simultaneously in order to describe the dynamics of different components of a low-temperature discharge plasma. The breakdown of a coaxial diode occurs in the form of a dense plasma region expanding from the cathode. On this background there is a formation of runaway electrons that are initiated by the ensemble of plasma electrons generated in the region of locally enhanced electric field within the front of the dense plasma. It is shown that the power spectrum of fast electrons in the discharge contains the group of electrons with the so-called “anomalous” energies. Comparison of the calculation results with the existent experimental data gives a good agreement for all major process parameters

A contemporary view of Blount's disease (literature review)

Introduction Blount's disease is a severe pediatric pathology of the musculoskeletal system. The condition is characterized by impaired growth and development of the proximal medial tibia and epiphysis, leading to varus deformity of the knee joint. Blount's disease is not just a cosmetic defect, but a serious orthopaedic condition accompanied by a gait disorder in a child. Patients with Blount's disease need surgical correction followed by longterm rehabilitation and can develop recurrence. The etiology of Blount's disease is unknown. Varus deformity of the knee joint is diagnosed in children all over the world, but studies on this pathology are few. There is a paucity of publications in the modern Russian literature reporting the pathology. The objective was review the literature on the classification, diagnosis, etiology and treatment of Blount's disease. Material and methods Electronic databases of PubMed, Scopus, eLibrary were used to source literature on the topic. Results Blount's disease has been shown to be characterized by disordered growth of the medial aspect of the proximal tibial physis and epiphysis that results in a three-dimensional deformity of the lower limb. In recent years, significant progress has been made in the diagnosis and surgical treatment of the cohort of patients. The etiology of Blount disease is unknown, and it is currently thought to result from a multifactorial combination of hereditary, humoral, biomechanical, and developmental factors. Conclusion Genetic predisposition has been postulated in the development of Blount's disease in many studies. Multiple factors such as ethnicity, obesity and early walking age are thought to be the contributing elements to this disease. To understand the key factor of the disease, further study of the hereditary nature of this pathology is necessary

Thermally activated delayed fluorescence in a deep red dinuclear iridium( iii ) complex: a hidden mechanism for short luminescence lifetimes †

The high luminescence efficiency of cyclometallated iridium(iii) complexes, including those widely used in OLEDs, is typically attributed solely to the formally spin-forbidden phosphorescence process being facilitated by spin–orbit coupling with the Ir(iii) centre. In this work, we provide unequivocal evidence that an additional mechanism can also participate, namely a thermally activated delayed fluorescence (TADF) pathway. TADF is well-established in other materials, including in purely organic compounds, but has never been observed in iridium complexes. Our findings may transform the design of iridium(iii) complexes by including an additional, faster fluorescent radiative decay pathway. We discover it here in a new dinuclear complex, 1, of the form [Ir(N^C)2]2(μ-L), where N^C represents a conventional N^C-cyclometallating ligand, and L is a bis-N^O-chelating bridging ligand derived from 4,6-bis(2-hydroxyphenyl)-pyrimidine. Complex 1 forms selectively as the rac diastereoisomer upon reaction of [Ir(N^C)2(μ-Cl)]2 with H2L under mild conditions, with none of the alternative meso isomer being separated. Its structure is confirmed by X-ray diffraction. Complex 1 displays deep-red luminescence in solution or in polystyrene film at room temperature (λem = 643 nm). Variable-temperature emission spectroscopy uncovers the TADF pathway, involving the thermally activated re-population of S1 from T1. At room temperature, TADF reduces the photoluminescence lifetime in film by a factor of around 2, to 1 μs. The TADF pathway is associated with a small S1–T1 energy gap ΔEST of approximately 50 meV. Calculations that take into account the splitting of the T1 sublevels through spin–orbit coupling perfectly reproduce the experimentally observed temperature-dependence of the lifetime over the range 20–300K. A solution-processed OLED comprising 1 doped into the emitting layer at 5 wt% displays red electroluminescence, λEL = 625 nm, with an EQE of 5.5% and maximum luminance of 6300 cd m−2