Counterflow step-type bulk material cooler

Counterflow cooling is extensively used in many industries to recover the heat from hot materials coming out of kiln. The method for calculating a counterflow step-type bulk material cooler is proposed. It is based on a matrix model of heat balance for individual cooling stages. The proposed equation system allows calculating the required number of steps and airing flow rate. The method was used to design a cyclone heat exchanger for an alumina calcination furnace and a counterflow louvered proppant cooler. It allows taking into account the degree of heat transfer incompleteness at individual stages and minimizing air flow for cooling. Examples of industrial introduction are given. The applicability of the method for counterflow heaters calculating is noted. On the basis of the offered method, step counterflow coolers with louvers were developed and introduced. Such devices and calculation methods can be used to heat the material before being fed into the furnace. The use of step-type counterflow heat exchanger makes it possible to utilize the heat of bulk material leaving the furnace and the heat of exhaust gases. © Published under licence by IOP Publishing Ltd

Determination of Different Biological Factors on the Base of Dried Blood Spot Technology

It is well-known that distinct biological indices (analytes) have distinct variability. We try to use some mathematical algorithms to pick out a set of blood parameters which give an opportunity to retrieve the initial volume of the blood spotted, and use it to calculate exact concentrations of analyts interesting to a physician. For our analysis we used the database of biochemical blood parameters obtained in Russian Scientific Center of Roentgen-Radiology during 1995-2000, which includes more than 30000 of patients.Comment: 5 page

Structure of 2-Methyl-5,6,7-triphenyl-6,7-dihydropyrazolo[2,3-\u3cem\u3ea\u3c/em\u3e]pyrimidine

C25H21N3, Mr = 363.46, monoclinic, P21/n, a = 9.245 (2), b = 23.502 (5), c = 9.340 (2) Å, β= 103.50(3)°, V=1973.3(2) Å3, Z=4, Dx= 1.220 (2) g cm-3, λ (Mo Kα )= 0.71069 Å, μ = 0.068 cm-1, F(000) = 768, T= 292 K, R = 0.091 for 1442 unique observed reflections. The dihydropyrimidine ring adopts a distorted sofa conformation. The aryl substituents on the saturated C atoms have an axial orientation

Vacuum effects in an asymptotically uniformly accelerated frame with a constant magnetic field

In the present article we solve the Dirac-Pauli and Klein Gordon equations in an asymptotically uniformly accelerated frame when a constant magnetic field is present. We compute, via the Bogoliubov coefficients, the density of scalar and spin 1/2 particles created. We discuss the role played by the magnetic field and the thermal character of the spectrum.Comment: 17 pages. RevTe

Determining Optimal Mining Work Size on the OpenCL Platform for the Ethereum Cryptocurrency

In terms of cryptocurrency, mining is a process of creating a new transaction block to add it to the blockchain. The cryptocurrency protocol should ensure the reliability of new transaction blocks. One of the popular mining protocols is the Proof-of-Work protocol, which requires the miner to perform a certain work to verify its right to add a new block into the blockchain. To perform this work, high-performance hardware is used, such as GPU. On the program level, hardware needs special computing framework, for example, CUDA or OpenCL. In this article, we discuss Ethereum cryptocurrency mining using the OpenCL standard. The Ethereum cryptocurrency is the most popular cryptocurrency with GPU-based mining. There are several open-source implementations of the Ethereum cryptocurrency miners. The host-part of the OpenCL-miner is considered, which makes the research results independent of the mining algorithm and allows using the results of the research in the mining of other cryptocurrencies. During the research, we have found the problems, which lead to mining productivity loss, and we are looking for the ways to resolve these problems and thus increase mining performance. As part of solving these problems, we have developed the algorithm for the functioning of the miner and proposed the methodology of determining the optimal size of OpenCL work, which allows to reduce the impact of problems found and achieve maximum mining productivity using OpenCL framework

Application of the YOLOv5 Model for the Detection of Microobjects in the Marine Environment

The efficiency of using the YOLOV5 machine learning model for solving the problem of automatic de-tection and recognition of micro-objects in the marine environment is studied. Samples of microplankton and microplastics were prepared, according to which a database of classified images was collected for training an image recognition neural network. The results of experiments using a trained network to find micro-objects in photo and video images in real time are presented. Experimental studies have shown high efficiency, comparable to manual recognition, of the proposed model in solving problems of detect-ing micro-objects in the marine environment.Comment: 9 pages, 8 figure

Marangoni instability in oblate droplets suspended on a circular frame

We study theoretically internal flows in a small oblate droplet suspended on the circular frame. Marangoni convection arises due to a vertical temperature gradient across the drop and is driven by the surface tension variations at the free drop interface. Using the analytical basis for the solutions of Stokes equation in coordinates of oblate spheroid we have derived the linearly independent stationary solutions for Marangoni convection in terms of Stokes stream functions. The numerical simulations of the thermocapillary motion in the drops are used to study the onset of the stationary regime. Both analytical and numerical calculations predict the axially-symmetric circulatory convection motion in the drop, the dynamics of which is determined by the magnitude of the temperature gradient across the drop. The analytical solutions for the critical temperature distribution and velocity fields are obtained for the large temperature gradients across the oblate drop. These solutions reveal the lateral separation of the critical and stationary motions within the drops. The critical vortices are localized near the central part of a drop, while the intensive stationary flow is located closer to its butt end. A crossover to the limit of the plane film is studied within the formalism of the stream functions by reducing the droplet ellipticity ratio to zero value. The initial stationary regime for the strongly oblate drops becomes unstable relative to the many-vortex perturbations in analogy with the plane fluid films with free boundaries