scholarly journals THE METHOD OF PROCESSING EXPERIMENTAL DATA AND THE ALGORITHM FOR ITS IMPLEMENTATION TO DETERMINE THE PARAMETERS OF THE RHEOLOGICAL MODEL OF A DILATANT LIQUID WITH THE EFFECT OF «SOLIDIFICATION»

2021 ◽  
pp. 101-106
Author(s):  
В.Н. Колодежнов ◽  
А.В. Колтаков ◽  
С.С. Капранчиков ◽  
А.С. Веретенников
Keyword(s):  
Experimental Data ◽  
Shear Rate ◽  
Rheological Model ◽  
Sharp Increase ◽  
Solid Phase ◽  
Threshold Value ◽  
Viscoplastic Fluid ◽  
High Concentration ◽  
Working Medium ◽  
Working Media

В различных технических приложениях применяются рабочие среды типа суспензий, которые при достаточно высокой концентрации частиц твердой фазы демонстрируют аномалии вязкости. Существо этих аномалий заключается в том, что при приближении скорости сдвига к некоторому пороговому значению наблюдается явление резкого возрастания вязкости жидкости. При этом в соответствующих зонах течения рабочая среда начинает вести себя подобно твердому телу. Механическое поведение такой рабочей среды может быть описано в рамках реологической модели вязкопластической жидкости, которая позволяет учитывать проявление эффекта“упрочнения” или “отвердевания”. Рассмотрена методика определения параметров такой реологической модели на основе обработки экспериментальных данных зависимости касательного напряжения от скорости сдвига. Предложен алгоритм для реализации этой методики. In various technical applications, working media such as suspensions are used, which, at a sufficiently high concentration of solid phase particles, demonstrate viscosity anomalies. The essence of these anomalies lies in the fact that when the shear rate approaches a certain threshold value, the phenomenon of a sharp increase in the viscosity of the liquid is observed. At the same time, in the corresponding flow zones, the working medium begins to behave like a solid. The mechanical behavior of such a working medium can be described within the framework of a rheological model of a viscoplastic fluid, which allows for the manifestation of the effect of “hardening” or “solidification”. The method of determining the parameters of such a rheological model based on the processing of experimental data on the dependence of the shear stress on the shear rate is considered. An algorithm for the implementation of this technique is proposed

scholarly journals NUMERICAL EXPERIMENTS WITH AN ALGORITHM FOR PROCESSING EXPERIMENTAL DATA TO DETERMINE THE PARAMETERS OF A RHEOLOGICAL MODEL OF A LIQUID WITH THE EFFECT OF «SOLIDIFICATION»

2021 ◽  
pp. 206-211
Author(s):  
В.Н. Колодежнов ◽  
А.В. Колтаков ◽  
С.С. Капранчиков ◽  
А.С. Веретенников
Keyword(s):  
Experimental Data ◽  
Polyethylene Glycol ◽  
Calcium Carbonate ◽  
Relative Error ◽  
Rheological Model ◽  
Numerical Experiments ◽  
Maximum Error ◽  
Viscoplastic Fluid ◽  
Maximum Relative Error ◽  
Hardening Effect

Предложена методика обработки экспериментальных данных и алгоритм для ее реализации по определению параметров реологической модели вязкопластической жидкости, которая демонстрирует проявление эффекта «отвердевания». С целью проверки работоспособности алгоритма проведены численные эксперименты с наборами генерируемых случайным образом “псевдоэкспериментальных” данных с заранее заданной величиной максимальной относительной погрешности. Проведен анализ влияния максимальной относительной погрешности исходных “псевдоэкспериментальных” данных на величину относительной погрешности определяемых в ходе численных экспериментов параметров реологической модели. По итогам проведенных экспериментов показано, что относительная погрешность определения параметров реологической модели соизмерима с максимальной погрешностью генерируемых “псевдоэкспериментальных” данных. Рассмотрен пример обработки экспериментальных данных для суспензии частиц карбоната кальция на основе полиэтиленгликоля. A technique for processing experimental data and an algorithm for its implementation to determine the parameters of a rheological model of a viscoplastic fluid, which demonstrates the manifestation of the "hardening" effect, are proposed. In order to test the algorithm's operability, numerical experiments were carried out with sets of randomly generated "pseudo-experimental" data with a predetermined maximum relative error. The analysis of the influence of the maximum relative error of the initial “pseudo-experimental” data on the value of the relative error of the parameters of the rheological model determined during numerical experiments was carried out. Based on the results of the conducted experiments, it is shown that the relative error in determining the parameters of the rheological model is commensurate with the maximum error of the generated “pseudo-experimental” data. An example of processing experimental data for a suspension of calcium carbonate particles based on polyethylene glycol is considered.

scholarly journals Dynamic Viscosity As A Function Of Shear Rate: The Comparison Of Established Rheological Models With The Newly Derived Rheological Model For The Estimation Of Zero– And Infinite–Shear Rate Viscosity Of Vegetable Oils

2012 ◽  
Author(s):  
Eng Giap Sunny Goh ◽  
Azira Amran
Keyword(s):  
Experimental Data ◽  
Shear Rate ◽  
Vegetable Oil ◽  
Rheological Model ◽  
Physical Parameters ◽  
Extreme Conditions ◽  
Newtonian Viscosity ◽  
Rheological Models ◽  
Rate Region ◽  
Low Shear

Kelikatan merupakan salah satu daripada parameter fizikal penting yang memerlukan pengukuran dengan kejituan, dan supaya ia dapat diwakili dengan persamaan reologi untuk membolehkan interpolasi nilai kelikatan yang tidak diketahui. Persamaan akan mempunyai kelebihan tambahan jika anggaran persamaan mampu memberi anggaran jitu penentuluaran. Sesetengah persamaan adalah mementingkan kejituan ramalan kelikatan dalam julat nilai eksperimen, sementara yang lain pula boleh membuat jangkaan kelikatan pada keadaan lampau, contohnya, kelikatan pada keadaan infiniti– and sifar–keterikan. Persamaan Cross and Carreau mampu untuk memberi nilai kelikatan pada keadaan lampau, tetapi anggaran keterikan awalan tidak boleh ditentusahkan jika data eksperimen tidak menunjukkan kewujudan sifat Newtonian. Dalam kajian ini, minyak tumbuhan kelapa, jagung, canola, dan soya dikaji dengan menggunakan viskometer pada keterikan yang berlainan, 3.9 – 131.6 s–1, dan keterikan adalah dilakukan pada suhu, 50 dan 90°C. Data eksperimen dipadankan dengan persamaan–persamaan reologi yang terkenal, dan kemudiannya, satu persamaan reologi baru diperkenalkan sebagai persamaan altenatif kepada pengiraan kelikatan pada kawasan keterikan rendah. Infiniti–keterikan kelikatan daripada persamaan baru adalah setara dengan nilai–nilai daripada persamaan–persamaan reologi terkenal. Di samping itu, keputusan menunjukkan kelikatan minyak tumbuhan mempunyai ciri pseudoplastic, dan data eksperimen dapat dimodelkan dengan persamaan baru dengan baik (R2 > 0.96). Kata kunci: Kelikatan; keterikan; reologi; minyak tumbuhan; Newtonian Viscosity is one of the most important physical parameters that need proper measurement in terms of its accuracy, and to be fitted by rheological model to enable interpolation for unknown viscosity. It would be an advantage if the model estimation could be extended for viscosity extrapolation with reliability. Some models are concerned with the accuracy of predicting viscosity within the experimental range value, while others able to predict viscosity at extreme conditions, for instance, viscosity at infinite– and zero–shear rate conditions. Cross and Carreau are able to model viscosity at extreme conditions, but its estimation value at very low shear rate region could not be justified if the experimental data does not signify the presence of Newtonian behaviour. In this study, coconut, corn, canola, and soy oils were investigated with a viscometer at different shear rates, 3.9 – 131.6 s–1, and were sheared at specific temperatures, 50 and 90°C. The experimental data were curve–fitted with wellknown rheological models, and then, a new rheological model was proposed as an alternative equation for viscosity estimation at low shear rate region. Infinite–shear rate viscosity from the new model is consistent with the estimation from well–known models. In addition, results showed that vegetable oil has the characteristic of a pseudoplastic, and the experimental data were well fitted by the new proposed model (R2 > 0.96). Key words: Viscosity; shear rate; rheology; vegetable oil; Newtonian

Thixotropic Behavior of Semisolid AlSi6Mg2 Alloy under Cyclic Shear Deformation

2012 ◽  
Vol 487 ◽  
pp. 487-490
Author(s):  
Hong Chao Luo ◽  
Ying Wu ◽  
Shi Pu Chen ◽  
En Sheng Xu
Keyword(s):  
Experimental Data ◽  
Shear Rate ◽  
Hysteresis Loop ◽  
Shear Deformation ◽  
Rheological Model ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Cyclic Shear ◽  
Thixotropic Behavior ◽  
The Difference

In the present work, the rheological model (CF model) developed by Chen and Fan[1] for semisolid metal slurries (SSMS) is applied to investigate the thixotropy of the AlSi6Mg2 alloy under cyclic shear deformation. The present investigation indicates that the semisolid AlSi6Mg2 alloy has the thixotropy by the technique of hysteresis loop. Specifically, the area of the hysteresis loop increases with decreasing the up-time, the initial shear rate and increasing resting time, solid volume fraction and maximum shear rate, respectively. These results agree qualitatively with the experimental data. Furthermore, the origin of the hysteresis loop is attributed to the difference between the agglomeration rate and the deagglomeration rate.

Improving the efficiency and reliability of electric power generation at incineration plants

2020 ◽  
Vol 12 (4) ◽  
pp. 281-285
Author(s):  
A. V. Martynov ◽  
N. E. Kutko
Keyword(s):  
Low Temperature ◽  
Power Plants ◽  
Thermal Power ◽  
Moscow Region ◽  
Capital Costs ◽  
Working Medium ◽  
The Creation ◽  
Working Media ◽  
Near Future ◽  
Efficiency And Reliability

The article deals with the problem of waste disposal and, accordingly, landfills in the Moscow Region, which have now become the number 1 problem for the environment in Moscow and the Moscow Region. To solve this problem, incineration plants (IP) will be established in the near future. 4 plants will be located in the Moscow Region that will be able to eliminate 2800 thousand tons of waste per year. Burning of waste results in formation of slag making 25% of its volume, which has a very high temperature (1300.1500°C). An arrangement is considered, in which slag is sent to a water bath and heats the water to 50.90°C. This temperature is sufficient to evaporate any low-temperature substance (freons, limiting hydrocarbons, etc.), whereupon the steam of the low-temperature working medium is sent to a turbine, which produces additional electricity. The creation of a low-temperature thermal power plant (TPP) increases the reliability of electricity generation at the IP. The operation of low-temperature TPPs due to the heat of slag is very efficient, their efficiency factor being as high as 40.60%. In addition to the efficiency of TPPs, capital costs for the creation of additional devices at the IP are of great importance. Thermal power plants operating on slag are just such additional devices, so it is necessary to minimize the capital costs of their creation. In addition to equipment for the operation of TPPs, it is necessary to have a working medium in an amount determined by calculations. From the wide variety of working media, which are considered in the article, it is necessary to choose the substance with the lowest cost.

Quantitation of Δ8-THC, Δ9-THC, Cannabidiol and 10 Other Cannabinoids and Metabolites in Oral Fluid by HPLC–MS-MS

2020 ◽  
Author(s):  
Lin Lin ◽  
Piyadarsha Amaratunga ◽  
Jerome Reed ◽  
Pornkamol Huang ◽  
Bridget Lorenz Lemberg ◽  
...  
Keyword(s):  
Human Subject ◽  
High Performance ◽  
Oral Fluid ◽  
Solid Phase ◽  
Forensic Toxicology ◽  
High Concentration ◽  
Driving Impairment ◽  
Three Samples ◽  
Cannabidiolic Acid ◽  
Liquid Chromatography Tandem Mass

Abstract Quantitative analysis of Δ9-tetrahydrocannabinol (Δ9-THC) in oral fluid has gained increasing interest in clinical and forensic toxicology laboratories. New medicinal and/or recreational cannabinoid products require laboratories to distinguish different patterns of cannabinoid use. This study validated a high-performance liquid chromatography-tandem mass spectrometry method for 13 different cannabinoids, including (-)-trans-Δ8-tetrahydrocannabinol (Δ8-THC), (-)-trans-Δ9-tetrahydrocannabinol (Δ9-THC), cannabidiol (CBD), Δ9-tetrahydrocannabinolic acid-A (Δ9-THCA-A), cannabidiolic acid (CBDA), 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-Δ9-THC), 11-nor-9-carboxy-Δ9-tetrahydrocannabinol (Δ9-THCCOOH), tetrahydrocannabivarin (THCV), cannabidivarin (CBDV), cannabidiorcol (CBD-C1), cannabichromene (CBC), cannabinol (CBN) and cannabigerol (CBG), in oral fluid. Baseline separation was achieved in the entire quantitation range between Δ9-THC and its isomer Δ8-THC. The quantitation range of Δ9-THC, Δ8-THC and CBD was from 0.1 to 800 ng/mL. Two hundred human subject oral fluid samples were analyzed with this method after solid phase extraction. Among the 200 human subject oral fluid samples, all 13 cannabinoid analytes were confirmed in at least one sample. Δ8-THC was confirmed in 11 samples, with or without the presence of Δ9-THC. A high concentration of 11-OH-Δ9-THC or Δ9-THCCOOH (>400 ng/mL) was confirmed in three samples. CBD, Δ9-THCA-A, THCV, CBN and CBG were confirmed in 74, 39, 44, 107 and 112 of the 179 confirmed Δ9-THC-positive samples, respectively. The quantitation of multiple cannabinoids and metabolites in oral fluid simultaneously provides valuable information for revealing cannabinoid consumption and interpreting cannabinoid-induced driving impairment.

Application of biological activated carbon anaerobic reactor for treatment of hazardous chemicals

2006 ◽  
Vol 53 (11) ◽  
pp. 251-260 ◽  
Author(s):  
H. Tsuno ◽  
M. Kawamura ◽  
T. Oya
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Organic Compounds ◽  
Adsorptive Capacity ◽  
Biological Degradation ◽  
Hazardous Chemicals ◽  
High Concentration ◽  
Expanded Bed ◽  
Biological Activated Carbon ◽  
Anaerobic Reactor

An expanded-bed anaerobic reactor with granular activated carbon (GAC) medium has been developed to treat wastewaters that contain a high concentration of inhibitory and/or refractory organic compounds as well as readily degradable organic compounds. The process is characterised by a combination of two removal mechanisms; adsorption on GAC and biological degradation by microorganisms grown on GAC. Applicability of the reactor to treatment of phenol, chloroacetaldehyde (CAA), pentachlorophenol (PCP) and tetrachloroethylene (PCE) was discussed based on experimental data. All chemicals focused on here were removed well and stably at a removal efficiency of more than 98% even during starting operation and shock load operation. Chemicals in influent that exceeded biological degradation capacity was initially adsorbed on GAC and then gradually degraded, and hence the adsorptive capacity of GAC was regenerated biologically. These results proved that a biological activated carbon anaerobic reactor was effective for treatment of wastewater containing hazardous chemicals, especially for strongly absorbable chemicals, as well as readily degradable organic compounds at high concentration.

Influence of Fillers on the Viscosity Properties of One-Pack Polyurethane Sealants

2021 ◽  
Vol 410 ◽  
pp. 605-610
Author(s):  
Kseniya A. Timakova ◽  
Yuriy T. Panov ◽  
Evgeniy A. Timakov
Keyword(s):  
Shear Rate ◽  
Dynamic Viscosity ◽  
Sharp Increase ◽  
Sharp Decrease ◽  
Shear Forces ◽  
Complex Orientation ◽  
Developed Surface ◽  
Mineral Fillers ◽  
Constant Shear Rate ◽  
Shape Of Particles

The paper investigates the effect of fillers on the viscosity properties of one-pack polyurethane sealants. It is noted that with the introduction of such mineral fillers as Mikarb, Midol, MTD2 chalk and aluminum hydroxide, the dynamic viscosity of the composition increases uniformly, while when filled with chemically precipitated Calofort SV chalk and MT-GShM talc, an abnormally sharp increase in viscosity is observed. Such an increase in viscosity for Calofort SV is explained by a highly developed surface, in contrast to other fillers. Talc is characterized by a plate-like shape of particles, which leads to a complex orientation of talc particles in the composition and shear difficulties.It was found that a sealant filled with chemically precipitated chalk has more than 100 pts. wt.(parts by weight), per 100 pts. wt. of the prepolymer under the influence of shear forces (at a constant shear rate) during the first 10 minutes of exposure, a sharp decrease in viscosity is observed, which is characteristic of thixotropic compositions, reaching a constant value after 5-10 minutes. After 10 minutes, the thixotropy of the sealant is restored. Talc does not impart thixotropic properties to the sealant composition.

Influence of Imperfections in the Working Media on Diesel Engine Indicator Process: Part 2 — Results

1998 ◽  
Author(s):  
Stanislav N. Danov ◽  
Ashwani K. Gupta
Keyword(s):  
Mathematical Model ◽  
Diesel Engine ◽  
High Pressures ◽  
Combustion Process ◽  
Ideal Gas ◽  
Working Medium ◽  
High Pressures And Temperatures ◽  
Specific Heat Capacities ◽  
Working Media ◽  
The Mathematical Model

Abstract In the companion Part 1 of this two-part series paper several improvements to the mathematical model of the energy conversion processes, taking place in a diesel engine cylinder, have been proposed. Analytical mathematical dependencies between thermal parameters (pressure, temperature, volume) and caloric parameters (internal energy, enthalpy, specific heat capacities) have been obtained. These equations have been used to provide an improved mathematical model of diesel engine indicator process. The model is based on the first law of thermodynamics, by taking into account imperfections in the working media which appear when working under high pressures and temperatures. The numerical solution of the simultaneous differential equations is obtained by Runge-Kutta type method. The results show that there are significant differences between the values calculated by equations for ideal gas and real gas under conditions of high pressures and temperatures. These equations are then used to solve the desired practical problem in two different two-stroke turbo-charged engines (8DKRN 74/160 and Sulzer-RLB66). The numerical experiments show that if the pressure is above 8 to 9 MPa, the working medium imperfections must be taken into consideration. The mathematical model presented here can also be used to model combustion process of other thermal engines, such as advanced gas turbine engines and rockets.

Rheological Properties and Anti-Aging Properties of PP/PP-g-AN Blends

2013 ◽  
Vol 815 ◽  
pp. 579-583 ◽  
Author(s):  
Ya Zhen Wang ◽  
Cheng E Yue ◽  
Di Ma ◽  
Wei Nan Jia ◽  
Yong Li
Keyword(s):  
Shear Rate ◽  
Rheological Properties ◽  
Solid Phase ◽  
Testing Time ◽  
Pseudoplastic Fluid ◽  
Aging Properties

The effect of PP-g-AN prepared by solid phase grafting on the blends of PP/PP-g-AN was investigated in this paper. The influence of aging testing time, PP-g-AN additives concentration, shear rate on the rheological properties and anti-aging properties of PP/PP-g-AN were mainly discussed. The results show that PP/PP-g-AN blends are pseudoplastic fluid and the presence of PP-g-AN can restrain the degradation of polypropylene when the content of PP-g-AN is in a certain range.

Sign in / Sign up

Export Citation Format

Share Document