scholarly journals Estimated justification of the bearing capacity of the lining when opening auxiliary workings in conditions of local freezing of the rock mass

2019 ◽  
Vol 6 (3) ◽  
Author(s):  
Sergey Koval ◽  
Ekaterina Pestryakova ◽  
Aleksandr Piskunov ◽  
Feodor Kiselev ◽  
Mihail Erofeev ◽  
...  
Keyword(s):  
Soil Mass ◽  
Dynamic Problems ◽  
The Finite Element Method ◽  
Two Phase ◽  
Lagrange Formulation ◽  
Phase Medium ◽  
Water Saturated ◽  
The Impact ◽  
Theory Of Plastic Flow ◽  
Sand Massif

For performance of works on the device of tunnel constructions in the conditions of the water-saturated unstable soils having character floating, their stabilization and strengthening is provided. During the construction of combined ventilation and technological failure of the existing subway, planned for the production of construction and installation works by mining in water-saturated fine Sands, provides for the implementation of measures to freeze the soil mass. For the safe construction of the workings of the decision on the implementation of the calculations and mathematical modeling of the impact on the lining and tongue and groove fencing in the production of works for freezing, opening the lining and thawing of the soil array. The article presents the results of analytical studies of the state of the rock sand massif in freezing conditions. The algorithm of numerical realization of the spatial inelastic problem using the method of finite differences and finite elements of MacCormack of the second order for dynamic problems is used and implemented to calculate the structure on mechanical effects. The finite element method is used in the Lagrange formulation of dynamic and static problems. The model of concrete and soil, described by the theory of plastic flow for shear, taking into account the rate of loading under volumetric deformation, is applied. To solve static (quasi-static problems), the method of establishing an explicit implementation or a quasi-static method in the absence of inertial terms is used. The layered two-phase medium, each layer of which is homogeneous and isotropic, is considered. This medium simulates the behavior of water-saturated soil, one phase of which is in the melt, and the other in the frozen state.

scholarly journals Analysis of the Foundation Slab Settlement of the “Africa Pavilion” Facility in Wrocław

2015 ◽  
Vol 37 (4) ◽  
pp. 47-55
Author(s):  
Eugeniusz Sawicki ◽  
Tomasz Strzelecki
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Calculations ◽  
Soil Consolidation ◽  
The Finite Element Method ◽  
Two Phase ◽  
Foundation Slab ◽  
Consolidation Theory ◽  
Phase Medium ◽  
Biot’S Consolidation

Abstract This article presents the results of numerical calculations of soil consolidation underneath the “Africa Pavilion” structure in Wrocław Zoo, Poland. To determine the deformations of the baseplate of the “Africa Pavilion” and deformations of the subsoil, Biot’s consolidation theory for two-phase medium was applied. The calculations were carried out using the professional program FlexPDE v.6, which is based on the Finite Element Method. Numerical calculations performed were used to evaluate the design assumptions allowing for the laying of hydraulic conduits under the slab.

The Numerical Simulation and Performance Analysis of the Vortex Pump for Solid-Liquid Two Phase Medium

2014 ◽  
Vol 527 ◽  
pp. 88-92
Author(s):  
Peng Yun Song ◽  
Hong Li Wang ◽  
Peng Cheng He
Keyword(s):  
Numerical Simulation ◽  
Volume Fraction ◽  
Internal Flow ◽  
Solid Particles ◽  
Two Phase ◽  
Pump Head ◽  
Phase Medium ◽  
And Performance ◽  
Solid Liquid ◽  
The Impact

The numerical simulation of a 3-D model of the internal flow field for a Vortex slurry pump has been analyzed in this paper. The impact of different solids volume fraction on the distribution of solid particle was analyzed. The expression of the pump head and efficiency was derived by the energy equation. The results show that either on the long blades or on the short blades, the content of the solid particles increases with the increasing of the volume fraction. The results by the expression of the pump head and efficiency are compared with the results of the simulations. The conclusions show that the expression results are similar with the numerical simulation results, and the main factors of affecting the inner and outer characteristics are the solid particles.

SYNTHESIS OF HYDROGEN IN ACOUSTOPLASMA DISCHARGE IN A LIQUID-PHASE STREAM

2019 ◽  
pp. 42-48 ◽  
Author(s):  
N. A. Bulychev
Keyword(s):  
Liquid Phase ◽  
Organic Compounds ◽  
Electrode Materials ◽  
Solid Phase ◽  
Plasma Discharge ◽  
Raw Material ◽  
Two Phase ◽  
Reduced Pressure ◽  
External Power Source ◽  
Phase Medium

In this paper, the plasma discharge in a high-pressure fluid stream in order to produce gaseous hydrogen was studied. Methods and equipment have been developed for the excitation of a plasma discharge in a stream of liquid medium. The fluid flow under excessive pressure is directed to a hydrodynamic emitter located at the reactor inlet where a supersonic two-phase vapor-liquid flow under reduced pressure is formed in the liquid due to the pressure drop and decrease in the flow enthalpy. Electrodes are located in the reactor where an electric field is created using an external power source (the strength of the field exceeds the breakdown threshold of this two-phase medium) leading to theinitiation of a low-temperature glow quasi-stationary plasma discharge.A theoretical estimation of the parameters of this type of discharge has been carried out. It is shown that the lowtemperature plasma initiated under the flow conditions of a liquid-phase medium in the discharge gap between the electrodes can effectively decompose the hydrogen-containing molecules of organic compounds in a liquid with the formation of gaseous products where the content of hydrogen is more than 90%. In the process simulation, theoretical calculations of the voltage and discharge current were also made which are in good agreement with the experimental data. The reaction unit used in the experiments was of a volume of 50 ml and reaction capacity appeared to be about 1.5 liters of hydrogen per minute when using a mixture of oxygen-containing organic compounds as a raw material. During their decomposition in plasma, solid-phase products are also formed in insignificant amounts: carbon nanoparticles and oxide nanoparticles of discharge electrode materials.

Some 1-substitution derivatives of 4-aryl-2,3-dihalogeno-1-naphthols

1984 ◽  
Vol 49 (1) ◽  
pp. 110-121 ◽  
Author(s):  
Jiří Křepelka ◽  
Drahuše Vlčková ◽  
Milan Mělka
Keyword(s):  
Thionyl Chloride ◽  
Oxirane Ring ◽  
Secondary Amines ◽  
Two Phase ◽  
Lytic Effect ◽  
Primary And Secondary Amines ◽  
Phase Medium ◽  
Chloro Derivatives ◽  
Derivatives Of

Alkylation of derivatives of 4-aryl-1-naphthols (I-V) by 2,3-epoxypropyl chloride in methanolic sodium hydroxide gave epoxy derivatives VI, VIII, IX, XI and XII, apart from products of cleavage of the oxirane ring, VII and X. Analogous alkylation of compounds I, IV and V by 2-(N,N-diethylamino)ethyl chloride hydrochloride in a two-phase medium afforded basic ethers XIII to XV. The cleavage of the oxirane ring in compound VI by the action of primary and secondary amines, piperidine and substituted piperazines led to compounds XVI-XXIV. Reaction of thionyl chloride with compounds XXI, XXII and XXIV gave chloro derivatives XXV-XXVII.Exposure of compound XXII to 4-methylbenzenesulfonyl chloride produced compound XXVIII, retaining the secondary alcoholic group. In an antineoplastic screening in vivo none of the compounds prepared had an appreciable activity. Compound XVII, being an analogue of propranolol, was used in the test of isoproterenolic tachycardia, and showed a beta-lytic effect comparable with that of propranol.

scholarly journals Thermocapillary effects in two-phase medium and applications to metal-silicate separation

2021 ◽  
pp. 106640
Author(s):  
Yanick Ricard ◽  
Stéphane Labrosse ◽  
Hidenori Terasaki ◽  
David Bercovici
Keyword(s):  
Two Phase ◽  
Metal Silicate ◽  
Phase Medium

scholarly journals The effect of the outlet angle β2 on the thermomechanical behavior of a centrifugal compressor blade

2020 ◽  
Vol 29 (1) ◽  
pp. 1-8
Author(s):  
Ahmed Allali ◽  
Sadia Belbachir ◽  
Ahmed Alami ◽  
Belhadj Boucham ◽  
Abdelkader Lousdad
Keyword(s):  
Mechanical Behavior ◽  
Centrifugal Compressor ◽  
Three Dimensional ◽  
Complex Form ◽  
Compressor Blade ◽  
Stress Fields ◽  
The Finite Element Method ◽  
Mechanical Fatigue ◽  
Outlet Angle ◽  
The Impact

AbstractThe objective of this work lies in the three-dimensional study of the thermo mechanical behavior of a blade of a centrifugal compressor. Numerical modeling is performed on the computational code "ABAQUS" based on the finite element method. The aim is to study the impact of the change of types of blades, which are defined as a function of wheel output angle β2, on the stress fields and displacements coupled with the variation of the temperature.This coupling defines in a realistic way the thermo mechanical behavior of the blade where one can note the important concentrations of stresses and displacements in the different zones of its complex form as well as the effects at the edges. It will then be possible to prevent damage and cracks in the blades of the centrifugal compressor leading to its failure which can be caused by the thermal or mechanical fatigue of the material with which the wheel is manufactured.

scholarly journals The Effect of Health Shock and Basic Medical Insurance on Family Educational Investment for Children in China

2021 ◽  
Vol 18 (10) ◽  
pp. 5242
Author(s):  
Pu Liao ◽  
Zhihong Dou ◽  
Xingxing Guo
Keyword(s):  
Negative Impact ◽  
Medical Insurance ◽  
Generation Model ◽  
Two Phase ◽  
Parental Health ◽  
Health Shock ◽  
Basic Medical Insurance ◽  
Child Education ◽  
The Impact ◽  
Basic Medical

This paper explores the role of basic medical insurance in protecting family investment in child education. First, this paper establishes a two-phase overlapping generation model to theoretically analyse the impact of basic medical insurance on investment in child education under the influence of the impact of parental health. The results show that health shock reduces parental investment in child education, and medical insurance significantly alleviates the negative impact of parental health shock on investment in child education. Furthermore, this paper establishes a two-way fixed effect regression model based on the data of China Family Panel Studies (CFPS) in 2014 and 2016 to empirically test the above results. The results showed that parental health shocks negatively affect investment in child education, and paternal health shock has a more significant impact than maternal health shock. However, medical insurance significantly reduces this negative impact, provides security in investment in child education, and promotes the improvement of human capital.

scholarly journals Exploring the impact of a decision support algorithm to improve clinicians’ chemotherapy-induced peripheral neuropathy assessment and management practices: a two-phase, longitudinal study

BMC Cancer ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Robert Knoerl ◽  
Emanuele Mazzola ◽  
Fangxin Hong ◽  
Elahe Salehi ◽  
Nadine McCleary ◽  
...  
Keyword(s):  
Decision Support ◽  
Peripheral Neuropathy ◽  
Management Practices ◽  
Management Strategies ◽  
Clinic Visit ◽  
Evidence Based ◽  
Two Phase ◽  
Assessment Index ◽  
Patient Reported ◽  
The Impact

Abstract Background Chemotherapy-induced peripheral neuropathy (CIPN) negatively affects physical function and chemotherapy dosing, yet, clinicians infrequently document CIPN assessment and/or adhere to evidence-based CIPN management in practice. The primary aims of this two-phase, pre-posttest study were to explore the impact of a CIPN clinician decision support algorithm on clinicians’ frequency of CIPN assessment documentation and adherence to evidence-based management. Methods One hundred sixty-two patients receiving neurotoxic chemotherapy (e.g., taxanes, platinums, or bortezomib) answered patient-reported outcome measures on CIPN severity and interference prior to three clinic visits at breast, gastrointestinal, or multiple myeloma outpatient clinics (n = 81 usual care phase [UCP], n = 81 algorithm phase [AP]). During the AP, study staff delivered a copy of the CIPN assessment and management algorithm to clinicians (N = 53) prior to each clinic visit. Changes in clinicians’ CIPN assessment documentation (i.e., index of numbness, tingling, and/or CIPN pain documentation) and adherence to evidence-based management at the third clinic visit were compared between the AP and UCP using Pearson’s chi-squared test. Results Clinicians’ frequency of adherence to evidence-based CIPN management was higher in the AP (29/52 [56%]) than the UCP (20/46 [43%]), but the change was not statistically significant (p = 0.31). There were no improvements in clinicians’ CIPN assessment frequency during the AP (assessment index = 0.5440) in comparison to during the UCP (assessment index = 0.6468). Conclusions Implementation of a clinician-decision support algorithm did not significantly improve clinicians’ CIPN assessment documentation or adherence to evidence-based management. Further research is needed to develop theory-based implementation interventions to bolster the frequency of CIPN assessment and use of evidence-based management strategies in practice. Trial registration ClinicalTrials.Gov, NCT03514680. Registered 21 April 2018.

scholarly journals Manufacturing, Characterisation and Mechanical Analysis of Polyacrylonitrile Membranes

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2378
Author(s):  
Mertol Tüfekci ◽  
Sevgi Güneş Durak ◽  
İnci Pir ◽  
Türkan Ormancı Acar ◽  
Güler Türkoğlu Demirkol ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Main Idea ◽  
Mechanical Analysis ◽  
Operating Conditions ◽  
Load Carrying Capacity ◽  
The Finite Element Method ◽  
Load Carrying ◽  
The Impact ◽  
Static Behaviour ◽  
Modelling Process

To investigate the effect of polyvinylpyrrolidone (PVP) addition and consequently porosity, two different sets of membranes are manufactured, since PVP is a widely used poring agent which has an impact on the mechanical properties of the membrane material. The first set (PAN 1) includes polyacrylonitrile (PAN) and the necessary solvent while the second set (PAN 2) is made of PAN and PVP. These membranes are put through several characterisation processes including tensile testing. The obtained data are used to model the static behaviour of the membranes with different geometries but similar loading and boundary conditions that represent their operating conditions. This modelling process is undertaken by using the finite element method. The main idea is to investigate how geometry affects the load-carrying capacity of the membranes. Alongside membrane modelling, their materials are modelled with representative elements with hexagonal and rectangular pore arrays (RE) to understand the impact of porosity on the mechanical properties. Exploring the results, the best geometry is found as the elliptic membrane with the aspect ratio 4 and the better RE as the hexagonal array which can predict the elastic properties with an approximate error of 12%.

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