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2021 ◽  
Vol 1 (74) ◽  
pp. 30-36
Author(s):  
A. Denisov ◽  
E. Denisova

In the article presented the results of infiltrating in Russia a new self-reproducing mechanism of nonviolent monopolization of power, targeted for ensuring the stable development of the state under condition of exception of system repressions against elite groups. Presented the basic mathematic model, placed in a basis of this method. And also, the means of its practical application for establishing a named mechanism.


2021 ◽  
Vol 50 (2) ◽  
pp. 50-54
Author(s):  
V. S. Prokhorova ◽  
N. G. Pavlova, ◽  
V. V. Kozlov ◽  
A. V. Novikova

Ultrasound investigation o f feta l biometry and haemodynamic indices in fetoplacental system during pregnancy since 14 weeks was carried out in 53 women havingtwins as a result o f spontaneous pregnancy or using o f assisted reproductive technology methods. The frequency and possible reasons oflU G R development in multiple pregnancy were analyzed. To predict the possibility o f IUG R in II and III trimester o f multiple pregnancy the mathematic model was worked out based on the standard fetometric indices measuring at 14-16 weeks o f pregnancy.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Duoxing Yang ◽  
Lianzhong Zhang

Propagation of pore pressure and stress in water-saturated elastic porous media is theoretically investigated when considering the Darcy-Brinkman law. The wave mode, phase velocity, phase lag, damping factor, and characteristic frequency are found from the updated mathematic model. The Brinkman term describes the fluid viscous shear effects and importantly contributes to the dispersion relation and wave damping. The coincidence of the properties of Biot waves of the first and second kinds occurs at a characteristic frequency, which is remarkably influenced by the Brinkman term. A key finding is that, compared to the Darcy-Brinkman law, Darcy’s law overestimates the phase velocity, damping, and phase lag of the first wave, while underestimates the phase velocity, damping, and phase difference of the second wave. The introduction of the Darcy-Brinkman law yields an improved description of the damping of the compressional wave modes in saturated porous media.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Chenghan Chen ◽  
Yanwei Wang ◽  
Furong Tan ◽  
Qili Zhu

Basic and theoretical research on processes such as reverse osmosis (RO) is essential in the fermentation industry to improve production efficiency and reduce cost. Here, we focus on the RO concentration of glucose solutions. We constructed a mathematic model that incorporates various membrane and experimental parameters to characterize the mass transfer process of RO membrane and validated the model output with experimental data. Calculation results were highly consistent with the experimental data, demonstrating that this model can be useful for predicting the RO concentration process.


Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1578
Author(s):  
Chenang Lyu ◽  
Leo Lou ◽  
Matthew J. Powell-Palm ◽  
Gideon Ukpai ◽  
Xing Li ◽  
...  

Porous dielectric membranes that perform insulator-based dielectrophoresis or electroosmotic pumping are commonly used in microchip technologies. However, there are few fundamental studies on the electrokinetic flow patterns of single microparticles around a single micropore in a thin dielectric film. Such a study would provide fundamental insights into the electrokinetic phenomena around a micropore, with practical applications regarding the manipulation of single cells and microparticles by focused electric fields. We have fabricated a device around a silicon nitride film with a single micropore (2–4 µm in diameter) which has the ability to locally focus electric fields on the micropore. Single microscale polystyrene beads were used to study the electrokinetic flow patterns. A mathematical model was developed to support the experimental study and evaluate the electric field distribution, fluid motion, and bead trajectories. Good agreement was found between the mathematic model and the experimental data. We show that the combination of electroosmotic flow and dielectrophoretic force induced by direct current through a single micropore can be used to trap, agglomerate, and repel microparticles around a single micropore without an external pump. The scale of our system is practically relevant for the manipulation of single mammalian cells, and we anticipate that our single-micropore approach will be directly employable in applications ranging from fundamental single cell analyses to high-precision single cell electroporation or cell fusion.


2021 ◽  
Author(s):  
Xiao Zheng ◽  
Jiajun Cui ◽  
Yixuan Wang ◽  
Jing Zhang ◽  
Chaochen Wang

AbstractCRISPR-based gene activation (CRISPRa) or interference (CRISPRi) are powerful and easy-to-use approaches to modify the transcription of endogenous genes in eukaryotes. Successful CRISPRa/i requires sgRNA binding and alteration of local chromatin structure, hence largely depends on the original epigenetic status of the target. Consequently, the efficacy of the CRISPRa/i varies in a wide range when applied to target different gene loci, while a reliable prediction tool is unavailable. To address this problem, we integrated published single cell RNA-Seq data involved CRISPRa/i and epigenomic profiles from K562 cells, identified the significant epigenetic features contributing to CRISPRa/i efficacy by ranking the weight of each feature. We further established a mathematic model and built a user-friendly webtool to predict the CRISPRa/i efficacy of customer-designed sgRNA in different cells. Moreover, we experimentally validated our model by employing CROP-Seq assays. Our work provides both the epigenetic insights into CRISPRa/i and an effective tool for the users.


2021 ◽  
Author(s):  
Fei Yang ◽  
Shengting Kuai ◽  
Zhe Wang

Thermal design of IGBT is the key technology on wind power converter design. This paper introduced a theoretical calculation method of IGBT power loss which is applicable in wind power converter engineering applications. Meantime, the corresponding mathematic model was established. Considering the divergence of application environments as well as the characteristics of water-cooling heat dissipation, simulation models of two different inlet and outlet position radiators were built in Ansys software. And then the cooling capacity of these two types of radiators was analyzed though simulation. According to the simulation results, the ipsilateral inlet and outlet channel mode radiator was selected. After the sample production of the water cooling plate is completed, the experimental platform is built and the sample was verified. Finally, the experiment results indicated the rationality and practicability of the thermal design and simulation, which provided critical references of IGBT water cooling system design. In this paper, the performance of water cooling radiators is studied, which also provides a reference for the design of other high power electronic products.


2021 ◽  
Vol 2131 (3) ◽  
pp. 032091
Author(s):  
A M Slidenko ◽  
V M Slidenko ◽  
S G Valyukhov

Abstract There have been examined the mathematic model of the impact device provided for geological materials destruction. Basic elements of the impact device are variable cross-section tool, striker and impact device body. The interaction of these elements is described as a movement of two discrete mass and the rod in the presence of rigid and dissipative connections. One equation in partial derivatives and two ordinary differential equations associated by initial and boundary conditions represent the initial-boundary problem. The numerical method parameters of which are determined at tests problems solution by Fourier method is used for looking for solutions of mixed initial-boundary problem. Researches are made, and parameters determining the damping efficiency of tool, striker and impact device body oscillations are evaluated.


2021 ◽  
Vol 939 (1) ◽  
pp. 012054
Author(s):  
Sh Rakhmanov ◽  
D Abdullaeva ◽  
N Azizova ◽  
A Nigmatov

Abstract This article devoted to the development of the mathematic model of the technological process of the chlorella cultivation process, its features and solving of this mathematic model. The Exponential growth of microalgae population under conditions of unlimited nutrient resources and population space proceeds at a rate proportional to the number of species of predominant cells and is described by the differential equation. In the presence of several inhibitors, specific velocity equations with the number of inhibitors can be used, but, as a rule, there are practically no elements acting as inhibitors in the cultivation of Chlorella microalgae. The modeling of this particular class of objects did not take into account the effect of inhibitors on the growth of microalgae. The consumption of nutrients to support the life of microalgae is described by the differential equation. In the course of this work, the processes of cultivation of microalgae were brought together into a system of equations. As a result, a system of differential equations of the technological process of Chlorella cultivation was obtained. Thus, the obtained system of equations describes the process of cultivation of microalgae and its technological process, implemented in a periodic mode.


2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Kailai Zhang ◽  
Liqun Xu ◽  
Liting Qiu ◽  
Jiacheng Tan ◽  
Chao Yang ◽  
...  

During the long-term service life of hydraulic structures, the calcium compounds in cement-based materials decompose in the aqueous environment, leading to the continuous change of seepage characteristics. To study the influence of calcium leaching on the concrete dam seepage characteristics, we proposed a new mathematic model of the cement-based material calcium leaching model under advection-diffusion-driven leaching. A solid-liquid nonequilibrium model is adopted to model the decomposition of calcium hydroxide (CH) and calcium silicate hydrate gel (C-S-H). To calculate the porosity more accurately, the proposed model takes the effect of different calcium compound decomposition on the porosity increase in consideration, respectively. Shimantan dam is selected for the three-dimensional (3D) calcium leaching analyses. The 3D finite element model of this dam is analyzed using COMSOL Multiphysics software that is based on the finite element method. Based on the proposed model, seepage characteristics evolutions of the Shimantan dam are studied. Good agreement between the numerical results and the monitored data indicates the accuracy of this simulation. The result shows that after 100 a leaching duration, the uplift pressure increases by 40.8%, and the leakage quantities of the dam body and foundation increase by 48 and 17 times. The rise of uplift pressure and leakage changes caused by curtain deterioration are the main influences of calcium leaching on the dam seepage. The parameter sensitivity results show that it is necessary to reduce CH content in cement-based materials to obtain better calcium leaching durability. This model and simulation results can guide the operation of concrete dams under advection-diffusion-driven leaching.


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