Controllable arrangement of integrated obstacles in silicon microchannels etched in 25 wt.% TMAX

In this paper, fabrication of silicon microchannels with integrated obstacles by using 25 wt.% tetramethylammonium hydroxide (TMAH) aqueous solution at the temperature of 80?C is presented and analysed. We studied basic island patterns, which present union of two symmetrical parallelograms with the sides along predetermined crystallographic directions <n10> (2<n<8) and <100>. Acute angles of the parallelograms were smaller than 45?. We have derived analytical relations for determining dimensions of the integrated obstacles. The developed etching technique provides reduction of the distance between the obstacles. Before the experiments, we performed simulations of pattern etching based on the level set method and presented evolution of the etched basic patterns for the predetermined crystallographic directions <n10>. Combination of basic patterns with sides along the <610> and <100> crystallographic directions is used to fabricate a matrix of two row of silicon obstacles in a microchannel. We obtained a good agreement between the experimental results and simulations. Our results enable simple and cost-effective fabrication of various complex microfluidic silicon platforms with integrated obstacles.

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Etching of Uncompensated Convex Corners with Sides along and in 25 wt% TMAH at 80 °C

Micromachines ◽

10.3390/mi11030253 ◽

2020 ◽

Vol 11 (3) ◽

pp. 253 ◽

Cited By ~ 2

Author(s):

Milče M. Smiljanić ◽

Žarko Lazić ◽

Vesna Jović ◽

Branislav Radjenović ◽

Marija Radmilović-Radjenović

Keyword(s):

Level Set Method ◽

Level Set ◽

Water Solution ◽

Wet Etching ◽

Tetramethylammonium Hydroxide ◽

Convex Corner ◽

Crystallographic Planes ◽

Good Agreement

This paper presents etching of convex corners with sides along <n10> and <100> crystallographic directions in a 25 wt% tetramethylammonium hydroxide (TMAH) water solution at 80 °C. We analyzed parallelograms as the mask patterns for anisotropic wet etching of Si (100). The sides of the parallelograms were designed along <n10> and <100> crystallographic directions (1 < n < 8). The acute corners of islands in the masking layer formed by <n10> and <100> crystallographic directions were smaller than 45°. All the crystallographic planes that appeared during etching in the experiment were determined. We found that the obtained types of 3D silicon shape sustain when n > 2. The convex corners were not distorted during etching. Therefore, no convex corner compensation is necessary. We fabricated three matrices of parallelograms with sides along crystallographic directions <310> and <100> as examples for possible applications. Additionally, the etching of matrices was simulated by the level set method. We obtained a good agreement between experiments and simulations.

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OPTIMIZATION OF LEVOFLOXACIN REMOVAL FROM AQUEOUS SOLUTION USING ELECTROCOAGULATION PROCESS BY RESPONSE SURFACE METHODOLOGY

IRAQI JOURNAL OF AGRICULTURAL SCIENCES ◽

10.36103/ijas.v52i1.1252 ◽

2021 ◽

Vol 52 (1) ◽

pp. 204-217

Author(s):

Mohammed & Mohammed-Ridha

Keyword(s):

Aqueous Solution ◽

Response Surface Methodology ◽

Response Surface ◽

Correlation Coefficient ◽

Iron Hydroxide ◽

Second Order ◽

Experimental Results ◽

Order Kinetic ◽

Experimental Conditions ◽

Good Agreement

This study was aimed to investigate the response surface methodology (RSM) to evaluate the effects of various experimental conditions on the removal of levofloxacin (LVX) from the aqueous solution by means of electrocoagulation (EC) technique with stainless steel electrodes. The EC process was achieved successfully with the efficiency of LVX removal of 90%. The results obtained from the regression analysis, showed that the data of experiential are better fitted to the polynomial model of second-order with the predicted correlation coefficient (pred. R2) of 0.723, adjusted correlation coefficient (Adj. R2) of 0.907 and correlation coefficient values (R2) of 0.952. This shows that the predicted models and experimental values are in good agreement. The results of the kinetic study showed that the second-order kinetic model was in good agreement with the experimental results and suggested that the mechanism of chemisorption controlled the LVX adsorption. The experimental results indicated that the adsorption of LVX on iron hydroxide flocs follows Sips isotherm with the value of the correlation coefficient (R2) of 0.937. Sips isotherm shows that both homogenous and heterogeneous adsorption can occur.

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An improved transmitter system to accurately measure wet-bulb temperature of air

Measurement and Control ◽

10.1177/0020294019858092 ◽

2019 ◽

Vol 52 (7-8) ◽

pp. 1002-1007

Author(s):

Liangwen Yan ◽

Peng Yu ◽

Sijung Hu ◽

Qiu Gao ◽

Wei Li ◽

...

Keyword(s):

Real Time ◽

Latent Heat ◽

Measurement Accuracy ◽

Cost Effective ◽

Mean Value ◽

Experimental Results ◽

Iteration Algorithm ◽

Good Consistency ◽

The Mean ◽

Good Agreement

A cost-effective measurement of wet-bulb temperature of air has great benefits to fulfill a growing demand of industry, cultivation agriculture, and medication. Applying an appropriate algorithm to wet-bulb temperature of air measurement can effectively improve the accuracy and speed of its measurement. The study aims to research how an improved transmitter system along with the latent heat–based iteration algorithm is used to precisely measure wet-bulb temperature of air. The work consists of (1) simulation of the iteration algorithm and (2) validation via experimental protocol. The simulation results through latent heat–based iteration algorithm were in good agreement ( R2≥ 0.99) with the reference. The performance of the improved wet-bulb temperature of air transmitter system was tested by a latent heat–based iteration algorithm experimental setup. The experimental results demonstrate that the improved wet-bulb temperature of air in a good consistency with commercial wet-bulb temperature of air in a range of temperature (15°C–34°C) and relative humidity (28.8%–76.2%). The Bland–Altman plot also shows that the mean value and the standard deviation of the differences between these two systems are 0.14°C and 0.29°C, respectively, which indicates that the improved wet-bulb temperature of air has a good agreement as well. Compared with the commercial wet-bulb temperature of air transmitter system, an advanced processor (STM32F103C8T6) and real-time operating system was applied in the improved wet-bulb temperature of air transmitter system. The experimental results show that its measurement accuracy is closer to the previous study. This study provides an alternative and cost-effective solution to accurately and real-time measure wet-bulb temperature of air.

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Computation of a Propagating Interface in Multiphase Flows Using an Adaptive Coupled Level Set Method

5th International Symposium on Fluid Structure International, Aeroeslasticity, and Flow Induced Vibration and Noise ◽

10.1115/imece2002-39044 ◽

2002 ◽

Author(s):

Ruquan Liang ◽

Satoru Komori

Keyword(s):

Surface Tension ◽

Level Set Method ◽

Level Set ◽

Multiphase Flows ◽

Surface Tension Force ◽

Numerical Results ◽

Passive Transport ◽

Effect Of Surface ◽

Good Agreement ◽

Numerical Strategy

We present a numerical strategy for a propagating interface in multiphase flows using a level set method combined with a local mesh adaptative technique. We use the level set method to move the propagating interface in multiphase flows. We also use the local mesh adaptative technique to increase the grid resolution at regions near the propagating interface and additionally at the regions near points of high curvature with a minimum of additional expense. For illustration, we apply the adaptive coupled level set method to a collection of bubbles moving under passive transport. Good agreement has been obtained in the comparision of the numerical results for the collection of bubbles using an adaptative grid with those using a single grid. We also apply the adaptive coupled level set method to a droplet falling on a step where it is important to accurately model the effect of surface tension force and the motion of the free-surface, and the numerical results agree very closely with available data.

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Competing Front for Directed Surface Extraction from CT Images

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.195-196.534 ◽

2012 ◽

Vol 195-196 ◽

pp. 534-538

Author(s):

Xue Shu Liu

Keyword(s):

Level Set Method ◽

Level Set ◽

Ct Images ◽

Experimental Results ◽

Second Step ◽

Simple Method ◽

Zero Level ◽

Interior Surface ◽

Surface Extraction ◽

Speed Function

Outward directed surface extraction from imaging modalities is the first task in the design of implants. In this paper a method based on level set method is proposed to extract the directed surface from CT images. The process is composed of two steps. In the first step, Level Set method with a new speed function is employed to evolve zero level set to its destination and used to cut the desired bone part from the input CT images. In the second step, a simple method is used to extract the directed surface, usually the outward surface, from the separated bone part by removing the interior surface. The experimental results show the proposed method works well.

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A Novel Multiphase Level Set Method to Image Segmentation Combined with Edge-Link Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.850-851.839 ◽

2013 ◽

Vol 850-851 ◽

pp. 839-843

Author(s):

Hong Jiang Wu ◽

Hai Yan Zhao ◽

Jin Meng ◽

Jing Zhao

Keyword(s):

Image Segmentation ◽

Level Set Method ◽

Level Set ◽

Human Motion ◽

Experimental Results ◽

Zero Level ◽

Level Set Segmentation ◽

Initial Zero

An improved level set PDE based on the Chan-Vese multiphase level set method is proposed. Because the segmentation results is well influenced by the initial zero level set, we use the method based on Edge-Link to obtain initial zero level set of the proposed multiphase level set segmentation model. Experimental results of ambiguous edges in human motion image suggest the efficiency and accuracy of the algorithm in its segmentation operations.

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Optimization of Level Set Segmentation with Nonlinear Coherent Diffusion

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.787.896 ◽

2013 ◽

Vol 787 ◽

pp. 896-901

Author(s):

Yong Hui Gao ◽

Sheng Zheng Wang ◽

Jie Yang

Keyword(s):

Image Segmentation ◽

Level Set Method ◽

Level Set ◽

Experimental Results ◽

Segmentation Result ◽

Gaussian Filter ◽

Robust Method ◽

Level Set Segmentation ◽

Fine Structures ◽

Spatially Varying

Level set method is convenient in image segmentation for the stabilization and veracity. Gaussian filter is usually taken as a preprocess to reduce the influence of weak edges due to noises, but the disadvantage is obvious: blur fine structures specially the important boundaries and lead to inaccurate segmentation result. This paper introduces a robust method which filters the images with a Nonlinear Coherent Diffusion (NCD) to accelerate the evolution of level set in a spatially varying manner. Experimental results show the performance of the proposed method in improving precision of segmentation.

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A description of crevasse formation using continuum damage mechanics

Annals of Glaciology ◽

10.3189/172756403781816077 ◽

2003 ◽

Vol 37 ◽

pp. 77-82 ◽

Cited By ~ 31

Author(s):

Antoine Pralong ◽

Martin Funk ◽

Martin P. Lüthi

Keyword(s):

Level Set Method ◽

Level Set ◽

Damage Mechanics ◽

Continuum Damage Mechanics ◽

Continuum Damage ◽

Interface Motion ◽

Glacier Surface ◽

Polycrystalline Ice ◽

Isotropic Damage ◽

Good Agreement

AbstractContinuum damage mechanics describes the progressive deterioration of material subjected to loading. Jointly used with a level-set method, it proves to be a promising approach to computing the interface motion of a damaged material. For polycrystalline ice, a local isotropic damage evolution law (generalized Kachanow’s law) applied to Glen’s flow law allows the description of tertiary creep and facilitates the modeling of crevasse opening using a failure criterion based on damage accumulation. The use of a level-set method permits the description, in a continuum approach, of the motion of a fractured glacier surface. Using these methods, a model is developed. The ability of this model to describe phenomena connected to crevasse opening is presented. The rupture of a large ice block from a hanging glacier is computed and analyzed. The regular acceleration of such an unstable ice block prior to its collapse is calculated and compared to the acceleration function obtained from observations. A good agreement between the two acceleration functions was found.

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Numerical Simulation of Film Boiling Near Critical Pressures With a Level Set Method

Journal of Heat Transfer ◽

10.1115/1.2830042 ◽

1998 ◽

Vol 120 (1) ◽

pp. 183-192 ◽

Cited By ~ 196

Author(s):

G. Son ◽

V. K. Dhir

Keyword(s):

Experimental Data ◽

Numerical Simulation ◽

Level Set Method ◽

Level Set ◽

Vapor Phase ◽

Film Boiling ◽

Release Pattern ◽

Wall Superheat ◽

Change Effect ◽

Good Agreement

Attempts have recently been made to numerically simulate film boiling on a horizontal surface. It has been observed from experiments and numerical simulations that during film boiling the bubbles are released alternatively at the nodes and antinodes of a Taylor wave. Near the critical state, however, hydrodynamic transition in bubble release pattern has been reported in the literature. The purpose of this work is to understand the mechanism of the transition in bubble release pattern through complete numerical simulation of the evolution of the vapor-liquid interface. The interface is captured by a level set method which is modified to include the liquid-vapor phase change effect. It is found from the numerical simulation that at low wall superheats the interface moves upwards, bubbles break off, and the interface drops down alternatively at the nodes and antinodes. However, with an increase in wall superheat, stable vapor jets are formed on both the nodes and antinodes and bubbles are released from the top of the vapor columns. The numerical results are compared with the experimental data, and visual observations reported in the literature are found to be in good agreement with the data.

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Evolution of Si Crystallographic Planes-Etching of Square and Circle Patterns in 25 wt % TMAH

Micromachines ◽

10.3390/mi10020102 ◽

2019 ◽

Vol 10 (2) ◽

pp. 102 ◽

Cited By ~ 3

Author(s):

Milče Smiljanić ◽

Žarko Lazić ◽

Branislav Radjenović ◽

Marija Radmilović-Radjenović ◽

Vesna Jović

Keyword(s):

Level Set Method ◽

Level Set ◽

Silicon Substrate ◽

Water Solution ◽

Three Dimensional ◽

Silicon Etching ◽

3D Simulations ◽

Circle Patterns ◽

Crystallographic Planes ◽

Good Agreement

Squares and circles are basic patterns for most mask designs of silicon microdevices. Evolution of etched Si crystallographic planes defined by square and circle patterns in the masking layer is presented and analyzed in this paper. The sides of square patterns in the masking layer are designed along predetermined <n10> crystallographic directions. Etching of a (100) silicon substrate is performed in 25 wt % tetramethylammonium hydroxide (TMAH) water solution at the temperature of 80 °C. Additionally, this paper presents three-dimensional (3D) simulations of the profile evolution during silicon etching of designed patterns based on the level-set method. We analyzed etching of designed patterns in the shape of square and circle islands. The crystallographic planes that appear during etching of 3D structures in the experiment and simulated etching profiles are determined. A good agreement between dominant crystallographic planes through experiments and simulations is obtained. The etch rates of dominant exposed crystallographic planes are also analytically calculated.

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