scholarly journals Fine-Tuning Electrokinetic Injections Considering Nonlinear Electrokinetic Effects in Insulator-Based Devices

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 628
Author(s):  
Abbi Miller ◽  
Nicole Hill ◽  
Kel Hakim ◽  
Blanca H. Lapizco-Encinas
Keyword(s):  
Mathematical Modeling ◽  
Direct Current ◽  
Electric Field Distribution ◽  
Particle Migration ◽  
Fine Tuning ◽  
Comsol Multiphysics ◽  
Sample Injection ◽  
Injection Process ◽  
Particle Separations

The manner of sample injection is critical in microscale electrokinetic (EK) separations, as the resolution of a separation greatly depends on sample quality and how the sample is introduced into the system. There is a significant wealth of knowledge on the development of EK injection methodologies that range from simple and straightforward approaches to sophisticated schemes. The present study focused on the development of optimized EK sample injection schemes for direct current insulator-based EK (DC-iEK) systems. These are microchannels that contain arrays of insulating structures; the presence of these structures creates a nonuniform electric field distribution when a potential is applied, resulting in enhanced nonlinear EK effects. Recently, it was reported that the nonlinear EK effect of electrophoresis of the second kind plays a major role in particle migration in DC-iEK systems. This study presents a methodology for designing EK sample injection schemes that consider the nonlinear EK effects exerted on the particles being injected. Mathematical modeling with COMSOL Multiphysics was employed to identify proper voltages to be used during the EK injection process. Then, a T-microchannel with insulating posts was employed to experimentally perform EK injection and separate a sample containing two types of similar polystyrene particles. The quality of the EK injections was assessed by comparing the resolution (Rs) and number of plates (N) of the experimental particle separations. The findings of this study establish the importance of considering nonlinear EK effects when planning for successful EK injection schemes.

ABOUT NECESSITY OF MATHEMATICAL MODELING OF THE BUSINESS PROCESS OF COST ESTIMATE CALCULATIONS IN THE CONSTRUCTION OF OIL AND GAS FACILITIES

2017 ◽  
pp. 139-145
Author(s):  
R. I. Hamidullin ◽  
L. B. Senkevich
Keyword(s):  
Mathematical Modeling ◽  
Quality Assessment ◽  
Business Process ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Gas Industry ◽  
Construction Organizations ◽  
The Cost ◽  
Cost Of Construction

A study of the quality of the development of estimate documentation on the cost of construction at all stages of the implementation of large projects in the oil and gas industry is conducted. The main problems that arise in construction organizations are indicated. The analysis of the choice of the perfect methodology of mathematical modeling of the investigated business process for improving the activity of budget calculations, conducting quality assessment of estimates and criteria for automation of design estimates is performed.

scholarly journals The use of mathematical modelling to analyse the process of mixing waters from different sources in water supply system

2018 ◽  
Vol 59 ◽  
pp. 00025
Author(s):  
Agnieszka Szuster – Janiaczyk ◽  
Rafał Brodziak ◽  
Jędrzej Bylka
Keyword(s):  
Mathematical Modeling ◽  
Water Quality ◽  
Quality Criteria ◽  
Supply System ◽  
Network Control ◽  
Quality Of Water ◽  
Water Mains ◽  
Different Sources ◽  
Mixing Water

One of the processes that significantly determines the quality of water to consumers is the process of mixing water from different sources in the water mains. Put to the network two or more chemically and biologically stable waters may result in the formation of water that will be deprived of these features. This article presents the german guidelines for analysing water quality for mixing waters from different sources, in various proportions. Then performed an analysis of utility the mathematical models,including quality criteria, for use in network control. An IT tool has been developed to manage selected water quality processes using mathematical modeling. The basis for implementing the tool was a network model created in Epanet integrated with the Matlab.

Effects of Two-Step DC Electrochemical Pretreatment of Fine Grinding WC-Co Tool Surface on Morphology and Quality of Diamond Coatings

2011 ◽  
Vol 337 ◽  
pp. 59-62
Author(s):  
Xiang Hui Zhang ◽  
Ling Wang ◽  
Jian Ping Long
Keyword(s):  
Surface Morphology ◽  
Direct Current ◽  
Arc Discharge ◽  
Etching Time ◽  
Diamond Coating ◽  
Diamond Coatings ◽  
Fine Grinding ◽  
Electrolytic Etching ◽  
Electrochemical Pretreatment

In the present investigation, diamond coating was deposited on fine grinding cemented carbide substrate by direct current arc discharge chemical vapor deposition. The effect of electrolytic etching time in the two-step electrochemical pretreatment process (firstly using electrolytic etching, and then using acid etching) on morphology and quality of the diamond coating were systemically studied. The surface morphology feature and quality of diamond coatings were characterized by means of Scanning Electron Microscope (SEM), laser Raman spectrometer respectively. The results showed that the electrolytic etching duration has distinctly effect on the quality and crystal features such as morphology, crystal type and grain size of diamond coating. It showed that as electrolytic current is direct current 3A, electrolytic etching time altering from 0.5 min to 7.5min, the surface morphology of diamond films gradually transition from microcrystalline cubic-octahedron to cauliflower type nanocluster, and further increase the electrolytic etching time, will lead to several negative effects on the quality and nucleation of the coatings which is not only retard the diamond nucleation, but also promote the formation of graphite.

Proceso de Optimización y Evaluación de una Antena Micro-coaxial para el Tratamiento de Tumores Óseos

2021 ◽  
Author(s):  
◽  
S. E. Rojas Hernández
Keyword(s):  
Quality Of Life ◽  
Radiation Therapy ◽  
Thermal Ablation ◽  
Bone Tumors ◽  
Tumor Volume ◽  
Microwave Antenna ◽  
Comsol Multiphysics ◽  
Necrotic Tissue ◽  
The One

Bone tumors are commonly treated with surgery (amputation), radiation therapy, and chemotherapy; however, its side effects compromise the patient’ quality of life. Thermotherapy is a less aggressive alternative to treat these tumors. In thermal ablation temperatures between 60 °C-100 °C must be reached in the tumor. The process to design and optimize a one-slot microwave antenna by using COMSOL Multiphysics, is proposed. An axi-symmetric 2D parametric study was carried out, in which 576 scenarios (antenna designs) were analyzed to choose the one that allowed higher energy transmission, temperature increases in the ablation range, larger areas of necrotic tissue, etc. From this study, the best scenario was chosen to evaluate its performance by using a 3D anatomical model. The final optimized antenna presented a SWR = 1.45; moreover, it was possible to observed that the 67.35% of tumor volume reaches ablation temperatures.

scholarly journals Freeze-drying microscopy in mathematical modeling of a biomaterial freeze-drying

2012 ◽  
Vol 48 (2) ◽  
pp. 203-209 ◽  
Author(s):  
Camila Figueiredo Borgognoni ◽  
Joyce da Silva Bevilacqua ◽  
Ronaldo Nogueira de Moraes Pitombo
Keyword(s):  
Mathematical Modeling ◽  
Freeze Drying ◽  
Drying Process ◽  
Critical Temperatures ◽  
Fundamental Properties ◽  
Moving Interface ◽  
Energy Consuming ◽  
Sublimation Rates ◽  
Time And Energy

Transplantation brings hope for many patients. A multidisciplinary approach on this field aims at creating biologically functional tissues to be used as implants and prostheses. The freeze-drying process allows the fundamental properties of these materials to be preserved, making future manipulation and storage easier. Optimizing a freeze-drying cycle is of great importance since it aims at reducing process costs while increasing product quality of this time-and-energy-consuming process. Mathematical modeling comes as a tool to help a better understanding of the process variables behavior and consequently it helps optimization studies. Freeze-drying microscopy is a technique usually applied to determine critical temperatures of liquid formulations. It has been used in this work to determine the sublimation rates of a biological tissue freeze-drying. The sublimation rates were measured from the speed of the moving interface between the dried and the frozen layer under 21.33, 42.66 and 63.99 Pa. The studied variables were used in a theoretical model to simulate various temperature profiles of the freeze-drying process. Good agreement between the experimental and the simulated results was found.

scholarly journals Deep Learning-Based Water Crystal Classification

2022 ◽  
Vol 12 (2) ◽  
pp. 825
Author(s):  
Hien Doan Thi ◽  
Frederic Andres ◽  
Long Tran Quoc ◽  
Hiro Emoto ◽  
Michiko Hayashi ◽  
...  
Keyword(s):  
Deep Learning ◽  
Water Resources ◽  
Past Research ◽  
Fine Tuning ◽  
Quality Of Water ◽  
Snow Crystal ◽  
State Of Water ◽  
First World ◽  
Small Dataset

Much of the earth’s surface is covered by water. As was pointed out in the 2020 edition of the World Water Development Report, climate change challenges the sustainability of global water resources, so it is important to monitor the quality of water to preserve sustainable water resources. Quality of water can be related to the structure of water crystal, the solid-state of water, so methods to understand water crystals can help to improve water quality. As a first step, a water crystal exploratory analysis has been initiated with the cooperation with the Emoto Peace Project (EPP). The 5K EPP dataset has been created as the first world-wide small dataset of water crystals. Our research focused on reducing the inherent limitations when fitting machine learning models to the 5K EPP dataset. One major result is the classification of water crystals and how to split our small dataset into several related groups. Using the 5K EPP dataset of human observations and past research on snow crystal classification, we created a simple set of visual labels to identify water crystal shapes, in 13 categories. A deep learning-based method has been used to automatically do the classification task with a subset of the label dataset. The classification achieved high accuracy when using a fine-tuning technique.

scholarly journals The sensorless control system for controlling the speed of direct current motor

2019 ◽  
Vol 16 (3) ◽  
pp. 1171
Author(s):  
Khac-Khiem Nguyen ◽  
Trong-Thang Nguyen
Keyword(s):  
Direct Current ◽  
Pid Controller ◽  
Closed Loop ◽  
Dc Motor ◽  
State Equation ◽  
Dynamic State ◽  
Estimation Model ◽  
Loop Control ◽  
Quality Of Control

<p>This research aims to propose an algorithm for controlling the speed of the Direct Current (DC) motor in the absence of the sensor of speed. Based on the initial mathematical model of DC motor, the authors build the dynamic state equation of DC motor, and then build an estimation model to determine the speed of the DC motor without a sensor. The advantages of the proposed method are demonstrated through the closed-loop control model using the PID controller. In order for the results to be objective, we assume that the parameters of the DC motor in the estimation model are not known correctly. The results show that the quality of control in the absence of a sensor is equivalent to the case with the sensor.</p>

scholarly journals Dynamics of intraocular temperature during local hypothermia (experimental study and mathematical modeling)

2019 ◽  
pp. 383-388
Author(s):  
Lukyan Anatychuk ◽  
Roman Kobyliansky ◽  
Nataliya Pasyechnikova ◽  
Volodymyr Naumenko ◽  
Oleg Zadorozhnyy ◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Biological Tissues ◽  
Comsol Multiphysics ◽  
Rabbit Eye ◽  
Local Contact ◽  
Group 2 ◽  
Local Hypothermia ◽  
Group 1

Therapeutic hypothermia currently is successfully in various fields of medicine to protect biological tissues from ischemia. However the issue of changes in intraocular temperature under hypothermia remains poorly understood. Purpose. To study the dynamics of intraocular temperature in conditions of local hypothermia and on the basis of the obtained data to develop a mathematical model of thermophysical processes in the rabbit eye. Materials and methods. An in vivo experiment was performed on 10 rabbits (20 eyes). In group 1 (5 rabbits, 10 eyes), epibulbar and intraocular temperature was measured after local contact hypothermia through closed eyelids, in group 2 (5 rabbits, 10 eyes) after local contact hypothermia directly through the cornea. ока безпосередньо через рогівку. Для гіпотермії застосовувався гелевий акумулятор холоду температурою -10 °С. Для вимірювання температури в різних відділах ока застосовувався термоелектричний пристрій, розроблений Інститутом термоелектрики НАН і МОН України та ДУ «Інститут очних хвороб і тканинної терапії ім. В. П.Філатова НАМН України». Для розробки математичної моделі теплофізичних процесів в оці кролика використано пакет прикладних програм COMSOL Multiphysics. Результати. Температура склоподібного тіла в 1-й і 2-й групі тварин знизилася в порівнянні з вихідними даними відповідно на 2,8 °С і 5,4 °С. Температурний градієнт між зовнішньою поверхнею рогівки і середньою частиною склоподібного тіла ока кролика в 1-й групі становив 7,1 °С, у 2-й групі – 9,2 °С. На підставі отриманих експериментальних даних було розроблено схематичну, математичну та комп’ютерну моделі ока кролика з урахуванням його теплофізичних особливостей, кровообігу, процесів метаболізму і теплообміну. Висновки. У разі локальної контактної гіпотермії очей кролика відбувається зниження епібульбарної температури і температури внутрішньоочних середовищ, як під час охолодження безпосередньо зовнішньої поверхні рогівки, так і під час впливу холоду через закриті повіки. Ключові слова: внутрішньоочна температура, локальна гіпотермія, око кролика, математична модель ока. Для цитування: Анатичук ЛІ, Пасєчнікова НВ, Науменко ВО, Задорожний ОС, Назаретян РЕ, Кобилянський РР, Верешко ЄЮ. Динаміка внутрішньоочної температури в умовах локальної гіпотермії (експериментальне дослідження та математичне моделювання). Журнал Національної академії медичних наук України. 2019;25(4):383–8

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