Surface Treated PDMS by UV-Vis Light for Microfluidic Device

AbstractHydrophobic property of PDMS surface was improved by the 400 W UV-Vis lamp light irradiation in the atmospheric condition for several ten minutes. As a result of this surface treatment, the surface became to hydrophilic character for one month long. This surface treatment technique applied to PDMS micro-fluidic device and verified valve-less switching. The UV-Vis light irradiated to PDMS micro fluidic pattern with partly covered by aluminum foil. Finally inlet and outlets were connected 0.5 mm diameter tubes. The syringe pumps injected the distilled water into the inlet of the PDMS micro channel at the flow rates of 0.5, 5.0, and 50 μl/min for the both width channel. As results of water injection water flowed only the UV-Vis treated channel at the flow rates of 0.5 and 5.0 μl/min. On the other hand, the water flowed for all channels at the flow rate of 50 μl/min. This result was observed from 5.0 μl/min flow again for both width devices which dried by air. These results were occurred by the difference of the flow conductance and wettability. The mechanism of this hyrophilicity of PDMS was reported to form Si-O in the surface by means of glassy surface. From the IR spectra, the Si-O-Si peak shifted to higher wave number for UV-Vis irradiated PDMS than the untreated PDMS comparing with the other IR peaks. This result showed that the Si-O-Si network bonding of PDMS changed to the O-Si-O bonding around the surface.

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Stable Deposition and Patterning of Metal Layers on the PDMS Substrate and Characterization for the Development of the Flexible and Implantable Micro Electrode

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.124-126.165 ◽

2007 ◽

Vol 124-126 ◽

pp. 165-168 ◽

Cited By ~ 13

Author(s):

Ju Yeoul Baek ◽

Gu Han Kwon ◽

Jeong Yun Kim ◽

Jin Ho Cho ◽

Seung Ha Lee ◽

...

Keyword(s):

Surface Treatment ◽

Oxygen Plasma ◽

Metal Layer ◽

The Other ◽

Pdms Substrate ◽

Pdms Surface ◽

Plasma Ions ◽

Implantable Electrodes ◽

Layer Deposition ◽

Metal Layers

PDMS(polydimethylsiloxane) is a flexible and biocompatible material and is widely used in bio- or medical-related fields. Recently, PDMS has been used as a substrate of implantable electrodes but has exhibited limits in stable metal layer deposition and patterning. In this paper, we have developed processes for both the stable metallization of PDMS surface and the selective patterning of conductive elements. The surface treatment via the oxygen plasma ions significantly affects the adhesion of metal layers to the PDMS surface, while the other factors exhibited no significant relations. On the basis of our procedure resulted in the effective production of the stable and fine (line width: 20 ) electrode patterns on the PDMS substrate. Finally, we fabricated PDMS-based flexible and implantable micro electrode for the subretinal prosthesis.

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A new algorithm for finding CRM-model coefficients

Tyumen State University Herald Physical and Mathematical Modeling Oil Gas Energy ◽

10.21684/2411-7978-2019-5-3-164-185 ◽

2019 ◽

Vol 5 (3) ◽

pp. 164-185 ◽

Cited By ~ 1

Author(s):

Alexander D. Bekman ◽

Sergey V. Stepanov ◽

Alexander A. Ruchkin ◽

Dmitry V. Zelenin

Keyword(s):

Approximate Solution ◽

Optimization Problem ◽

Optimal Solution ◽

Complex Form ◽

Approximate Solutions ◽

The Other ◽

Programming Algorithm ◽

Stochastic Algorithms ◽

Large Set ◽

Flow Rates

The quantitative evaluation of producer and injector well interference based on well operation data (profiles of flow rates/injectivities and bottomhole/reservoir pressures) with the help of CRM (Capacitance-Resistive Models) is an optimization problem with large set of variables and constraints. The analytical solution cannot be found because of the complex form of the objective function for this problem. Attempts to find the solution with stochastic algorithms take unacceptable time and the result may be far from the optimal solution. Besides, the use of universal (commercial) optimizers hides the details of step by step solution from the user, for example — the ambiguity of the solution as the result of data inaccuracy.<br> The present article concerns two variants of CRM problem. The authors present a new algorithm of solving the problems with the help of “General Quadratic Programming Algorithm”. The main advantage of the new algorithm is the greater performance in comparison with the other known algorithms. Its other advantage is the possibility of an ambiguity analysis. This article studies the conditions which guarantee that the first variant of problem has a unique solution, which can be found with the presented algorithm. Another algorithm for finding the approximate solution for the second variant of the problem is also considered. The method of visualization of approximate solutions set is presented. The results of experiments comparing the new algorithm with some previously known are given.

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Effect of surface treatments on push-out bond strength of calcium silicate-based cements to fiber posts

BMC Oral Health ◽

10.1186/s12903-021-01518-y ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Amr M. Elnaghy ◽

Ayman Mandorah ◽

Ali H. Hassan ◽

Alaa Elshazli ◽

Shaymaa Elsaka

Keyword(s):

Bond Strength ◽

Surface Treatment ◽

Glass Fiber ◽

Calcium Silicate ◽

Surface Treatments ◽

The Other ◽

Fiber Posts ◽

Glass Fiber Posts ◽

Push Out ◽

Effect Of Surface

Abstract Background To evaluate the effect of surface treatments on the push-out bond strength of Biodentine (BD) and white mineral trioxide aggregate (WMTA) to fiber posts. Methods Two brands of fiber posts were used: Reblida post; RP and RelyX post; RX. Each type of post (n = 80/group) was divided into four groups (n = 20/group) and exposed to surface treatment as follows: Control (no treatment), sandblasting (SB), hydrofluoric acid (HF), and TiF4 4 wt/v%. Each group was further subdivided into two subgroups (n = 10/subgroup) based on the type of CSCs used as follows: Subgroup A: BD and Subgroup B: WMTA. Push-out bond strength of BD and WMTA to glass fiber posts was assessed. Data were statistically analyzed using three-way ANOVA and Tukey’s test. A Weibull analysis was performed on the push-out bond strength data. Results BD showed higher bond strength than WMTA (P < 0.001). The push-out bond strength for posts treated with TiF4 4 wt/v% showed greater bond strength than the other surface treatments (P < 0.05). The BD/RP-TiF4 4 wt/v% showed the greater characteristic bond strength (σ0) (15.93) compared with the other groups. Surface treatments modified the surface topography of glass fiber posts. Conclusions The BD/RP-TiF4 4 wt/v% showed greater bond strength compared with the other groups. The TiF4 4 wt/v% surface treatment enhanced the bond strength of BD and WMTA to glass fiber posts than the other treatments. Surface treatment of fiber post with TiF4 4 wt/v% could be used to improve the bond strength with calcium silicate-based cements.

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Optimization of Inlet Ring Groove Arrangement for Suppression of Unstable Flow in a Centrifugal Impeller

Volume 6: Turbo Expo 2005, Parts A and B ◽

10.1115/gt2005-68675 ◽

2005 ◽

Cited By ~ 3

Author(s):

Masahiro Ishida ◽

Daisaku Sakaguchi ◽

Hironobu Ueki

Keyword(s):

Flow Rate ◽

The Other ◽

Centrifugal Impeller ◽

Shape Parameters ◽

Unstable Flow ◽

Ring Groove ◽

Flow Rates ◽

Small Flow ◽

Specific Speed ◽

Large Flow

An optimization of the inlet ring groove arrangement has been pursued in the present study for obtaining better impeller characteristics and a wider operation range at both small and large flow rates in a high specific speed type centrifugal impeller with inducer. The effects of the shape parameters with respect to the inlet ring groove on the impeller characteristic and the flow incidence were analyzed mainly based on numerical simulations, but also compared to the experimental results. At small flow rates, a significant improvement in the impeller characteristic is achieved due to reduction in the excessive-positive flow incidence by optimizing both location and width of the rear groove near the inducer tip throat. On the other hand, the impeller characteristic is improved at large flow rates by implementing the corner radius at the rear groove edge and by placing another front ring groove in the suction pipe. As a result, by the optimized configuration of the front and rear ring grooves, the unstable flow range of the test impeller can be reduced by about 50% without deterioration of the impeller characteristic even at the 125% flow rate.

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Numerical Study on Flow and Heat Transfer of a Cooled First Stage Vane of a Gas Turbine

Volume 5A: Heat Transfer ◽

10.1115/gt2016-57977 ◽

2016 ◽

Author(s):

Lv Ye ◽

Zhao Liu ◽

Xiangyu Wang ◽

Zhenping Feng

Keyword(s):

Heat Transfer ◽

Gas Turbine ◽

Film Cooling ◽

Numerical Study ◽

Coolant Flow ◽

The Other ◽

Edge Region ◽

Flow Rates ◽

Flow And Heat Transfer ◽

Film Cooling Holes

This paper presents a numerical simulation of composite cooling on a first stage vane of a gas turbine, in which gas by fixed composition mixture is adopted. To investigate the flow and heat transfer characteristics, two internal chambers which contain multiple arrays of impingement holes are arranged in the vane, several arrays of pin-fins are arranged in the trailing edge region, and a few arrays of film cooling holes are arranged on the vane surfaces to form the cooling film. The coolant enters through the shroud inlet, and then divided into two parts. One part is transferred into the chamber in the leading edge region, and then after impinging on the target surfaces, it proceeds further to go through the film cooling holes distributed on the vane surface, while the other part enters into the second chamber immediately and then exits to the mainstream in two ways to effectively cool the other sections of the vane. In this study, five different coolant flow rates and six different inlet pressure ratios were investigated. All the cases were performed with the same domain grids and same boundary conditions. It can be concluded that for the internal surfaces, the heat transfer coefficient changes gradually with the coolant flow rate and the inlet total pressure ratio, while for the external surfaces, the average cooling effectiveness increases with the increase of coolant mass flow rates while decreases with the increase of the inlet stagnation pressure ratios within the study range.

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Preliminary Investigation on the Effect of the Modification of the Sweep Angle at the Blade Tip of Forward Swept Axial Fans

Volume 1: Aircraft Engine; Fans and Blowers; Marine; Honors and Awards ◽

10.1115/gt2017-63795 ◽

2017 ◽

Author(s):

Massimo Masi ◽

Andrea Lazzaretto

Keyword(s):

Preliminary Investigation ◽

Suction Side ◽

The Other ◽

Axial Fan ◽

Sweep Angle ◽

End Effects ◽

Flow Rates ◽

Stall Margin ◽

Other Hand ◽

Blade Tip

The flow path close to the suction side of fan rotor blades mostly affects the overall drag of the blading. The blade lift is affected as well because of the separation of the low energy boundary layer that drives the blade into stall at low fan flow rates. Forward sweep allows to position the airfoil sections of blades featuring a positive circulation gradient along the span so that they “accompany” the near-wall flow trajectories at the blade suction side. So, rotor efficiency and stall margin of the fan can be improved. On the other hand, blade end effects play a relevant role in high hub-to-tip and low aspect ratio rotors and may compromise the effectiveness of forward sweep. Nevertheless, some authors in the literature stated the beneficial contribution of changing the sweep angle at the ends of the blade both at design and off-design conditions. The paper studies the end effects on constant-swirl design rotors by means of CFD simulations focusing on the distribution of blade sweep in the near-tip region. In particular, the performance and efficiency calculated for a forward swept tube-axial fan featuring a hub-to-tip ratio equal to 0.4 are compared with those estimated for the corresponding unswept fan at equal duty point. Several modifications of the sweep distribution in the blade tip region are considered in the swept fan to quantify their effect on performance, efficiency and stall margin. Results show that the addition of up to 6 degrees of local forward sweep at the blade tip to the unswept blading does not affect fan pressure at design operation. On the other hand, this local increase of the sweep angle allows for a very notable increase of the peak pressure and efficiency at flow rates close to stall inception.

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New Surface-Treatment Technique of Concrete Structures Using Crack Repair Stick with Healing Ingredients

Materials ◽

10.3390/ma9080654 ◽

2016 ◽

Vol 9 (8) ◽

pp. 654 ◽

Cited By ~ 3

Author(s):

Tae-Ho Ahn ◽

Hong-gi Kim ◽

Jae-Suk Ryou

Keyword(s):

Surface Treatment ◽

Concrete Structures ◽

Treatment Technique ◽

Crack Repair

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Increased take-off level in automatic milking systems – effects on milk flow, milk yield and milking efficiency at the quarter level

Journal of Dairy Research ◽

10.1017/s002202991800078x ◽

2018 ◽

Vol 86 (1) ◽

pp. 85-87 ◽

Cited By ~ 1

Author(s):

Sabine Ferneborg ◽

Måns Thulin ◽

Sigrid Agenäs ◽

Kerstin Svennersten-Sjaunja ◽

Peter Krawczel ◽

...

Keyword(s):

Flow Rate ◽

The Other ◽

Mean Flow ◽

Flow Rates ◽

Decline Phase ◽

Flow Profiles ◽

Milk Flow ◽

Automatic Milking ◽

Automatic Milking Systems ◽

Time Required

AbstractThis research communication describes how different detachment levels (0.48, 0.3 and 0.06 kg milk/min) at the quarter-level affect milk flow profiles and overall milking efficiency in automatic milking systems. We hypothesized a higher detachment level would result in greater mean flow rates without affecting the volume of harvested milk per cow during 24 h compared to lower detachment levels. The data suggest milk flow decreased to a rate below the overmilking limit within the 6-s delay time required for termination in all treatments, but the duration of overmilking was shorter for the greatest detachment level compared to the other treatments. We conclude that setting a detachment level at a greater milk flow rate reduces the duration of overmilking without affecting the amount of milk harvested when applied to cows in mid-lactation during quarter-level milking. We also suggest that the steepness of the decline phase of the milk flow curve might have a larger effect than the actual detachment level on the duration of overmilking.

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