Effects of Cross-Section Geometry of Capillary on the Evaporation From the Meniscus

Author(s):  
Songwan Jin ◽  
Choonghyo Choi ◽  
Kenneth S. Breuer ◽  
Jung Yul Yoo

Effects of cross-section geometry of capillary on the evaporation from the meniscus have been investigated by adopting several circular and rectangular capillaries. The evaporating meniscus shape, evaporation rate and flow near the evaporating meniscus of various liquids such as water, ethanol and methanol are determined. The shapes of water and ethanol menisci in circular capillary are quite different from each other due to the difference in surface tension. But the difference in meniscus shapes is relatively small in rectangular channel. The averaged evaporation fluxes in rectangular channel are much larger than that in circular capillary. The rotating vortex motion is observed near the evaporating menisci of ethanol and methanol except for the case of methanol in 200 × 20-μm capillary. The reason for this is considered to be the existence of the corner menisci at the four corners.

2017 ◽  
Vol 830 ◽  
pp. 369-386 ◽  
Author(s):  
Stoffel D. Janssens ◽  
Vikash Chaurasia ◽  
Eliot Fried

We perform a static analysis of a circular cylinder that forms a barrier between surfactant-laden and surfactant-free portions of a liquid–gas interface. In addition to determining the general implications of the balances for forces and torques, we quantify how the imbalance $\unicode[STIX]{x0394}\unicode[STIX]{x1D6FE}=\unicode[STIX]{x1D6FE}_{a}-\unicode[STIX]{x1D6FE}_{b}$ between the uniform surface tension $\unicode[STIX]{x1D6FE}_{a}$ of the surfactant-free portion of the interface and the uniform surface tension $\unicode[STIX]{x1D6FE}_{b}$ of the surfactant-laden portion of the interface influences the load-bearing capacity of a hydrophobic cylinder. Moreover, we demonstrate that the difference between surface tensions on either side of a cylinder with a cross-section of arbitrary shape induces a horizontal force component $f^{h}$ equal to $\unicode[STIX]{x0394}\unicode[STIX]{x1D6FE}$ in magnitude, when measured per unit length of the cylinder. With an energetic argument, we show that this relation also applies to a rod-like barrier with cross-sections of variable shape. In addition, we apply our analysis to amphiphilic Janus cylinders and we discuss practical implications of our findings for Marangoni propulsion and surface pressure measurements.


KREATOR ◽  
2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Mawan Nugraha ◽  
Murdani Murdani

One of the main components of the fountain solution used for the offset printing technique is isoprophil alcohol (IPA), which is related to its function as a surface tension reducing agent, cooling agent for printing plates and at the same time having anti-bioorganic function. However, complaints have also been made about the weaknesses in the use of IPA related to odor, toxicity and too high evaporation rate during its use. Therefore, in this article, IPA is compared to the "alcohol-free" type when used in the field as a wetting solution mixture using a KBK offset printing machine to produce magazines using of AP 115 paper. The difference in the use of the two surfaces the tension reducing agents are identified by the waste parameters that are used, generated during consistent printing under controlled process conditions. The results obtained indicate that the use of IPA is always higher, but the use of `` non alcoholic '' tends to be more stable in controling the process.Keywords—Isoprophil Alcohol (IPA), alcohol-free fontain solution, offset printing


2012 ◽  
Vol 27 (2) ◽  
pp. 264-269 ◽  
Author(s):  
Christian Lorbach ◽  
Ulrich Hirn ◽  
Johannes Kritzinger ◽  
Wolfgang Bauer

Abstract We present a method for 3D measurement of fiber cross sectional morphology from handsheets. An automated procedure is used to acquire 3D datasets of fiber cross sectional images using an automated microtome and light microscopy. The fiber cross section geometry is extracted using digital image analysis. Simple sample preparation and highly automated image acquisition and image analysis are providing an efficient tool to analyze large samples. It is demonstrated that if fibers are tilted towards the image plane the images of fiber cross sections are always larger than the true fiber cross section geometry. In our analysis the tilting angles of the fibers to the image plane are measured. The resulting fiber cross sectional images are distorted to compensate the error due to fiber tilt, restoring the true fiber cross sectional shape. We use an approximated correction, the paper provides error estimates of the approximation. Measurement results for fiber wall thickness, fiber coarseness and fiber collapse are presented for one hardwood and one softwood pulp.


2021 ◽  
Vol 57 (35) ◽  
pp. 4287-4290
Author(s):  
Ryohei Yamakado ◽  
Issei Kitamura ◽  
Mitsuo Hara ◽  
Shusaku Nagano ◽  
Takahiro Seki ◽  
...  

Large mass transport driven by the difference in the photoisomerization-induced surface tension was demonstrated in ion pairs, enabling fluorescence patterning using a trace amount of photoisomerized anions in complexation with a π-electronic system.


2021 ◽  
Vol 11 (12) ◽  
pp. 5597
Author(s):  
Hussein A. Z. AL-bonsrulah ◽  
Mohammed J. Alshukri ◽  
Ammar I. Alsabery ◽  
Ishak Hashim

Proton exchange membrane fuel cell (PEM-FC) aggregation pressure causes extensive strains in cell segments. The compression of each segment takes place through the cell modeling method. In addition, a very heterogeneous compressive load is produced because of the recurrent channel rib design of the dipole plates, so that while high strains are provided below the rib, the domain continues in its initial uncompressed case under the ducts approximate to it. This leads to significant spatial variations in thermal and electrical connections and contact resistances (both in rib–GDL and membrane–GDL interfaces). Variations in heat, charge, and mass transfer rates within the GDL can affect the performance of the fuel cell (FC) and its lifetime. In this paper, two scenarios are considered to verify the performance and lifetime of the PEM-FC using different innovative channel geometries. The first scenario is conducted by adopting a constant channel height (H = 1 mm) for all the differently shaped channels studied. In contrast, the second scenario is conducted by taking a constant channel cross-sectional area (A = 1 mm2) for all the studied channels. Therefore, a computational fluid dynamics model (CFD) for a PEM fuel cell is formed through the assembly of FC to simulate the pressure variations inside it. The simulation results showed that a triangular cross-section channel provided the uniformity of the pressure distribution, with lower deformations and lower mechanical stresses. The analysis helped gain insights into the physical mechanisms that lead to the FC’s durability and identify important parameters under different conditions. The model shows that it can assume the intracellular pressure configuration toward durability and appearance containing limited experimental data. The results also proved that the better cell voltage occurs in the case of the rectangular channel cross-section, and therefore, higher power from the FC, although its durability is much lower compared to the durability of the triangular channel. The results also showed that the rectangular channel cross-section gave higher cell voltages, and therefore, higher power (0.63 W) from the fuel cell, although its durability is much lower compared to the durability of the triangular channel. Therefore, the triangular channel gives better performance compared to other innovative channels.


2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Giselle Nevares ◽  
Felipe Xavier ◽  
Luciana Gominho ◽  
Flávia Cavalcanti ◽  
Marcely Cassimiro ◽  
...  

This study aimed to analyse and compare apical extrusion of debris in canals instrumented with systems used in reciprocating and continuous motion. Sixty mandibular premolars were randomly divided into 3 groups (n=20): the Reciproc (REC), WaveOne (WO), and HyFlex CM (HYF) groups. One Eppendorf tube per tooth was weighed in advance on an analytical balance. The root canals were instrumented according to the manufacturer’s instructions, and standardised irrigation with 2.5% sodium hypochlorite was performed to a total volume of 9 mL. After instrumentation, the teeth were removed from the Eppendorf tubes and incubated at 37°C for 15 days to evaporate the liquid. The tubes were weighed again, and the difference between the initial and final weight was calculated to determine the weight of the debris. The data were statistically analysed using the Shapiro-Wilk, Wilcoxon, and Mann-Whitney tests (α=5%). All systems resulted in the apical extrusion of debris. Reciproc produced significantly more debris than WaveOne (p<0.05), and both systems produced a greater apical extrusion of debris than HyFlex CM (p<0.001). Cross section and motion influenced the results, despite tip standardization.


Author(s):  
A Jodat ◽  
M Moghiman

In the present study, the applicability of widely used evaporation models (Dalton approach-based correlations) is experimentally investigated for natural, forced, and combined convection regimes. A series of experimental measurements are carried out over a wide range of water temperatures and air velocities for 0.01 ≤ Gr/Re2 ≤ 100 in a heated rectangular pool. The investigations show that the evaporation rate strongly depends on the convection regime's Gr/ Re2 value. The results show that the evaporation rate increases with the difference in vapour pressures over both forced convection (0.01 ≤ Gr/Re2 ≤ 0.1) and turbulent mixed convection regimes (0.15 ≤ Gr/Re2 ≤ 25). However, the escalation rate of evaporation decreases with Gr/ Re2 in the forced convection regime whereas in the turbulent mixed convection it increases. In addition, over the range of the free convection regime ( Gr/Re2 ≥ 25), the evaporation rate is affected not only by the vapour pressure difference but also by the density variation. A dimensionless correlation using the experimental data of all convection regimes (0.01 ≤ Gr/Re2 ≤ 100) is proposed to cover different water surface geometries and airflow conditions.


2012 ◽  
Vol 223 (6) ◽  
pp. 1119-1136 ◽  
Author(s):  
Jan Awrejcewicz ◽  
Valeriy Storozhev ◽  
Vladimir Puzyrev

Author(s):  
Hareesh K. R. Kommepalli ◽  
Andrew D. Hirsh ◽  
Christopher D. Rahn ◽  
Srinivas A. Tadigadapa

This paper introduces a novel T-beam actuator fabricated by a piezoelectric MEMS fabrication process. ICP-RIE etching from the front and back of a bulk PZT chip is used to produce stair stepped structures through the thickness with complex inplane shapes. Masked electrode deposition creates active and passive regions in the PZT structure. With a T-shaped crosssection, and bottom and top flange and web electrodes, a cantilevered beam can bend in-plane and out-of-plane with bimorph actuation in both directions. One of these T-beam actuators is fabricated and experimentally tested. An experimentally validated model predicts that the cross-section geometry can be optimized to produce higher displacement and blocking force.


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