scholarly journals A Molecular Dynamics Study of Heat Transfer Enhancement during Phase Change from a Nanoengineered Solid Surface

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 715
Author(s):  
A. K. M. Monjur Morshed ◽  
Muhammad Rubayat Bin Shahadat ◽  
Md. Rakibul Hasan Roni ◽  
Ahmed Shafkat Masnoon ◽  
Saif Al-Afsan Shamim ◽  
...  
Keyword(s):  
Surface Area ◽  
Solid Surface ◽  
Solid Wall ◽  
Liquid Argon ◽  
Level Surface ◽  
Solid Base ◽  
Effective Surface Area ◽  
Effective Surface ◽  
Transportation Behavior ◽  
Rate Of Evaporation

This study investigates the enhancement of the rate of evaporation from a nanoengineered solid surface using non-equilibrium molecular dynamics simulation. Four different types of surface modifications were introduced to examine the thermal transportation behavior. The surface modification includes: (1) transformation of surface wetting condition from hydrophobic to hydrophilic, (2) implementing nanostructures on the smooth surface, (3) cutting nano slots on the smooth surface and (4) introducing nano-level surface roughness. Evaporation behavior from the same effective surface area was also studied. The simulation domain consisted of three distinct zones: solid base wall made of copper, a few layers of liquid argon, and a vapor zone made of argon. All the nano-level surface modifications were introduced on the solid base surface. The few layers of liquid argon representing the liquid zone of the domain take heat from the solid surface and get evaporated. Outside this solid and liquid zone, there is argon vapor. The simulation began at the initial time t = 0 ns and then was allowed to reach equilibrium. Immediately after equilibrium was achieved on all three-phase systems, the temperature of the solid wall was raised to a higher value. In this way, thermal transportation from the solid wall to liquid argon was established. As the temperature of the solid wall was high enough, the liquid argon tended to evaporate. From the simulation results, it is observed that during the transformation from hydrophobic to hydrophilic conditions, enhancement of evaporation takes place due to the improvement of thermal transportation behavior. At the nanostructure surface, the active nucleation sites and effective surface area increase which results in evaporation enhancement. With nano slots and nano-level surface roughness, the rate of evaporation increases due to the increase of solid-liquid contact area and effective surface area.

scholarly journals Surface characteristics influencing bacterial adhesion to polymeric substrates

RSC Advances ◽  
2017 ◽  
Vol 7 (23) ◽  
pp. 14254-14261 ◽  
Author(s):  
Yue Yuan ◽  
Michael P. Hays ◽  
Philip R. Hardwidge ◽  
Jooyoun Kim
Keyword(s):  
Surface Area ◽  
Solid Surface ◽  
Bacterial Adhesion ◽  
Surface Characteristics ◽  
Area Fraction ◽  
Effective Surface Area ◽  
Effective Surface ◽  
Polymeric Substrates ◽  
Solid Area

Effective surface area on rough substrates for bacterial adhesion is examined by analyzing the solid area fraction of surfaces, where the bacterial medium is in contact with the solid surface.

scholarly journals Synthesis of a hierarchical nanoporous carbon material with controllable pore size and effective surface area for high-performance electrochemical capacitors

RSC Advances ◽  
2017 ◽  
Vol 7 (24) ◽  
pp. 14516-14527 ◽  
Author(s):  
Bing Hu ◽  
Ling-Bin Kong ◽  
Long Kang ◽  
Kun Yan ◽  
Tong Zhang ◽  
...  
Keyword(s):  
Pore Size ◽  
Linear Relationship ◽  
Specific Capacitance ◽  
Surface Area ◽  
Carbon Material ◽  
High Performance ◽  
Electrode Materials ◽  
Effective Surface Area ◽  
Effective Surface ◽  
Nanoporous Carbon Material

There is an excellent linear relationship between E-SSA and specific capacitance of HNC-IPNs as electrode materials for EDLCs.

Microstructure and Gas Sensing Property of Porous SnO2 Sputtered Films

2007 ◽  
Vol 539-543 ◽  
pp. 3508-3513 ◽  
Author(s):  
Toshinari Yamazaki ◽  
Cheng Ji Jin ◽  
Yan Bai Shen ◽  
Toshio Kikuta ◽  
Noriyuki Nakatani
Keyword(s):  
Surface Area ◽  
Gas Sensing ◽  
Columnar Structure ◽  
Oxide Semiconductor ◽  
Bet Surface Area ◽  
Semiconductor Film ◽  
Effective Surface Area ◽  
Effective Surface ◽  
Discharge Gas ◽  
Film Porosity

It is often said that the sensitivity of a gas sensor made of an oxide semiconductor film is enhanced by making the film porous. However, the porosity of sensor films has not been sufficiently examined. In this study, SnO2 films were deposited using DC magnetron sputtering under various substrate temperatures and discharge gas pressures. In addition to the structural analysis by means of X-ray diffraction and scanning electron microscopy, the density and the BET surface area were measured to clarify the film porosity. The sensitivity to H2 gas of undoped and Pd-doped SnO2 films upon exposure to 1000 ppm H2 was measured at 300 . SnO2 films generally showed a columnar structure. The film deposited at a low temperature and a high pressure showed a low density and a large effective surface area. The H2 sensitivity increased as the density decreased, that is, as the effective surface area increased.

Day-To-Day Variability of Protein Transport Used as a Method for Analyzing Peritoneal Permeability in CAPD

1991 ◽  
Vol 11 (3) ◽  
pp. 217-223 ◽  
Author(s):  
Désirée Zemel ◽  
Raymond T. Krediet ◽  
Gerardus C.M. Koomen ◽  
Dirk G. Struijk ◽  
Lambertus Arisz
Keyword(s):  
Surface Area ◽  
Structural Changes ◽  
Protein Transport ◽  
Intrinsic Permeability ◽  
Effective Surface Area ◽  
Intraindividual Variation ◽  
Effective Surface ◽  
Peritoneal Surface ◽  
Beta 2 ◽  
Beta 2 Microglobulin

The transperitoneal transport of macromolecules is dependent on both effective peritoneal surface area and intrinsic permeability of the peritoneum. For passage of small solutes, the effective surface area is the main determinant. We hypothesized that day-to-day variations in peritoneal clearances are caused by changes in the effective surface area and not in the intrinsic permeability. Four CAPD {continuous ambulatory peritoneal dialysis) patients without peritonitis were investigated on 28 consecutive days. Concentrations of beta-2-microglobulin, albumin, IgG, and alpha-2-macroglobulin were determined daily in dialysate {night bags) and weekly in serum. Clearances and their coefficients of variation were calculated. Mean coefficients of the intraindividual variation of protein clearances increased, the higher the molecular weight: they ranged from 12% for beta-2microglobulin clearance to 22% for alpha-2-macroglobulin clearance. Correlations were present between the clearances of albumin, IgG, and alpha-2-macroglobulin, but not between any of these and beta-2-microglobulin clearance. In all patients, protein clearance {C) was a power function of the free diffusion coefficient in water {D) according to the equation: C=a. Db in which b represents the restriction coefficient of the peritoneum, and thus intrinsic permeability. The coefficient of variation of the restriction coefficient was low (range 4–6%). This supports our assumption that the intrinsic permeability is fairly constant on the short term. Day-to-day variations in protein clearances are thus mainly caused by alterations in the effective peritoneal surface area. Longterm follow-up of the restriction coefficient in individual patients might identify those at risk for the development of structural changes in the peritoneal membrane.

Molecular Dynamics Study on Explosive Boiling of Thin Liquid Argon Film on Nanostructured Surface Under Different Wetting Conditions

2015 ◽  
Author(s):  
Sheikh Mohammad Shavik ◽  
Mohammad Nasim Hasan ◽  
A. K. M. Monjur Morshed
Keyword(s):  
Molecular Dynamics ◽  
Liquid Film ◽  
Solid Surface ◽  
Solid Wall ◽  
Thin Liquid Film ◽  
Liquid Argon ◽  
Spatial And Temporal Variation ◽  
Phase System ◽  
Explosive Boiling ◽  
System Pressure

Molecular dynamics (MD) simulations have been performed to investigate the boiling phenomena of thin liquid film adsorbed on a nanostructured solid surface with particular emphasis on the effect of wetting condition of the solid surface. The molecular system consists of liquid and vapor argon, and solid platinum wall. The nanostructures which reside on top of the solid wall have shape of rectangular block. The solid-liquid interfacial wettability, in other words whether the solid surface is hydrophilic or hydrophobic has been altered for different cases to examine its effect on boiling phenomena. The initial configuration of the simulation domain comprised a three phase system (solid platinum, liquid argon and vapor argon) which was equilibrated at 90 K. After equilibrium period, the wall temperature was suddenly increased from 90 K to 250 K which is far above the critical point of argon and this initiates rapid or explosive boiling. The spatial and temporal variation of temperature and density as well as the variation of system pressure with respect to time were closely monitored for each case. The heat flux normal to the solid surface was also calculated to illustrate the effectiveness of heat transfer for different cases of wetting conditions of solid surface. The results show that the wetting condition of surface has significant effect on explosive boiling of the thin liquid film. The surface with higher wettability (hydrophilic) provides more favorable conditions for boiling than the low-wetting surface (hydrophobic) and therefore, liquid argon responds quickly and shifts from liquid to vapor phase faster in case of hydrophilic surface.

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