Static Liquid Pressure Research Articles

Biocompatible bonding of a rigid off-stoichiometry thiol-ene-epoxy polymer microfluidic cartridge to a biofunctionalized silicon biosensor

Attachment of biorecognition molecules prior to microfluidic packaging is advantageous for many silicon biosensor-based lab-on-a-chip (LOC) devices. This necessitates biocompatible bonding of the microfluidic cartridge, which, due to thermal or chemical incompatibility, excludes standard microfabrication bonding techniques. Here, we demonstrate a novel processing approach for a commercially available, two-step curable polymer to obtain biocompatible ultraviolet initiated (UVA)-bonding of polymer microfluidics to silicon biosensors. Biocompatibility is assessed by UVA-bonding to antibody-functionalized ring resonator sensors and performing antigen capture assays while optically monitoring the sensor response. The assessments indicate normal biological function of the antibodies after UVA-bonding with selective binding to the target antigen. The bonding strength between polymer and silicon chips (non-biofunctionalized and biofunctionalized) is determined in terms of static liquid pressure. Polymer microfluidic cartridges are stored for more than 18 weeks between cartridge molding and cartridge-to-silicon bonding. All bonded devices withstand more than 2500 mbar pressure, far exceeding the typical requirements for LOC applications, while they may also be de-bonded after use. We suggest that these characteristics arise from bonding mainly through intermolecular forces, with a large extent of hydrogen bonds. Dimensional fidelity assessed by microscopy imaging shows less than 2% shrinkage through the molding process and the water contact angle is approximately 80°. As there is generally little absorption of UVA light (365 nm) in proteins and nucleic acids, this UVA-bonding procedure should be applicable for packaging a wide variety of biosensors into LOC systems.

Unidirectional transport of both wettable and nonwettable liquids on an asymmetrically concave structured surface

Unidirectional liquid transport (UDLT) has been widely used in various fields as an important process for transferring both mass and energy. However, UDLT driven by a structural gradient has been witnessed for a long time only in wettable liquids. For nonwettable liquids, UDLT can hardly proceed merely by a structural gradient. Herein, we propose an asymmetrically concave structured surface (AMC-surface), featuring tip-to-base periodically arranged pyramid-shaped concave structures with a certain degree of overlap, which enables the UDLT of both wettable and nonwettable liquids. For wettable liquids, the capillary force along each corner leads to the UDLT pointing toward the base side of the concave pyramid, while for nonwettable liquids, the UDLT is attributable to the static liquid pressure overwhelming the repulsive Laplace pressure induced by the asymmetric grooves and overlapping part. As a result, both wettable and nonwettable liquids transport spontaneously and unidirectionally on the AMC-surface with no energy input. Moreover, the concave structure endows good mechanical stability and can be easily prepared using a facile nail-punching approach over a large area. We also demonstrated its application in a continuous chemical reaction in a confined area. We envision that the unique UDLT behavior on the as-developed AMC-surface will shed new light on the programmable manipulation of various liquids.

The Effect of PhET Simulation in Science Learning of Static Fluid Pressure Topics towards Students’ Creative Thinking Skill

This study aims to see is there a significant effect of the use of PhET simulations in science learning of static liquid pressure topics towards creative thinking skill of middle school students. This research was conducted at SMPIT Al-Ghozali Jember in 8th grade of C class and D class where each class consisted of 21 female students. The design of this research is Control Group Pretest-Posttest in which the learning in experimental class uses the PhET simulation while in control class uses the experimental video. The results of Wilcoxon Signed-Rank Test on students' creative thinking skill test scores are differed significantly both in the experimental class and the control class. The results of Mann-Whitney test are the students' student worksheets in the experimental class differed significantly from the control class. It can be concluded that there is a significant effect of the use of PhET simulations in this study.

Cooling Rate and Microstructural Investigation of Rapidly Solidified Spherical Mono-Sized Copper Particles

Spherical copper particles with diameter ranging from 120.6 to 437.0 μm were prepared by the pulsated orifice ejection method (termed “POEM”). These spherical copper particles exhibit a good spherical shape and a narrow size distribution, suggesting that the liquid copper can completely break the balance between the surface tension and the liquid static pressure in the crucible micropores and accurately control the volume of the droplets. Furthermore, the relationship between cooling rate and microstructures of spherical copper particles was carried out with a specific focus on different cooling atmosphere and particle diameter during the rapid solidification. The cooling rate of spherical copper particles is evaluated by a Newton’s cooling model. It is revealed that the cooling rate was depended on cooling medium and particle diameter. The cooling rate decreases and the grain size increases with the increase of particle diameter during the rapid solidification, while the grain boundary of same particle diameter with larger cooling rate in argon gas is smaller, while the grain boundary of particles with smaller cooling rate in helium gas is larger. When the particle diameter is larger than 100 μm, the cooling rate of the cooper droplet in argon gas achieves 1.0×104 K/s. Meanwhile, the cooling rate decreases rapidly when the particle diameter increased between 70.6 and 149.6 μm. It is an effective route for fabrication of high-quality spherical copper particles.

Characterization of Cooling Rate and Microstructure of Rapidly Solidified Spherical Mono-Sized Sn-1.0Ag-0.5Cu Particles

Spherical mono-sized Sn-1.0Ag-0.5Cu (wt.%) particles with diameter ranging from 124.0 to 337.4μm were prepared by the pulsated orifice ejection method (termed “POEM”).These spherical Sn-1.0Ag-0.5Cu particles exhibit a good spherical shape and a narrow size distribution, suggesting that liquid Sn-1.0Ag-0.5Cu can completely break the balance between the surface tension and the liquid static pressure in the crucible micropores and accurately control the volume of the droplets. Furthermore, the relationship between cooling rate and microstructures of spherical Sn-1.0Ag-0.5Cu particles was studied with a specific focus on different particle diameter during the rapid solidification. The cooling rate of spherical Sn-1.0Ag-0.5Cu particles with different diameter was evaluated by the Newton’s cooling model. It is revealed that the cooling rate decreases gradually with the increase of particle size during the rapidly solidified process. When the particle diameter is equal to 75 μm, the cooling rate of the Sn-1.0Ag-0.5Cu particle achieves 4.30×103 K/s which indicates that smaller particles can rapidly solidified due to their higher cooling rate. Meanwhile, the cooling rate decreases rapidly when the particle diameter increases between 75 and 100 μm. Furthermore, the different particle diameter with different cooling rate has a great influence on the solidification microstructure of Sn-1.0Ag-0.5Cu particles. The cooling rate and grain boundary size decreases with the increase of particle diameter during the rapid solidification. In addition, the phase size of βSn increases with the decrease of particle size. Smaller particles have relatively high cooling rate and it gives less solidification time as compared to larger particles. It is an effective route for fabrication of high-quality spherical Sn-1.0Ag-0.5Cu particles. Keywords: Spherical Sn-1.0Ag-0.5Cu particles; Rapid solidification; Structural; Cooling rate

Preparation and characterization of monosized Cu–Sn spherical alloy particles by pulsated orifice ejection method

Abstract

A fiber bragg grating pressure sensor with temperature compensation based on diaphragm-cantilever structure

Pressure sensors are essential devices for pressure measurement and safety evaluation in modern industrial production and engineering application. According to the FBG sensing technology, this paper presents and studies a FBG pressure sensor that uses a diaphragm and a cantilever as a sensing unit. Two FBGs of this sensor are bonded on the top and bottom surfaces of the cantilever, respectively, and the center wavelength shift difference between the two FBGs is used as a measuring signal, thus improving the pressure measuring sensitivity and avoiding any effect of temperature cross-sensitivity. The measuring principle of this sensor is introduced, and the diaphragm structure of the sensor is analyzed through theoretical calculation and finite element analysis. Experimental results indicate that this sensor has a sensitivity of 339.956pm/MPa and a linear fitting coefficient of 99.997% in the pressure range from 0 to 10MPa, and the maximum pressure measuring error caused in the temperature range from 5 to 70°C is 0.93%, so the temperature compensation effects are remarkable. Such a FBG pressure sensor can be extensively used for quasi-distributed long-term online monitoring of the static or dynamic pressure of liquid or gas in industrial production.

Hydrodynamic interaction of weakly nonspherical gas bubbles in a liquid in the three-dimensional problem statement

The influence of the relative location of weakly nonspherical gas (air) bubbles in liquid (water) on their hydrodynamic interaction at the pressure antinode of an ultrasonic standing wave is studied. Three essentially different configurations of the mutual arrangement of the bubbles are considered: the linear, planar, and spatial ones. In the linear configuration, three bubbles are located on one straight line. In the planar configuration, five bubbles are situated on two mutually orthogonal straight lines. In the spatial configuration, seven bubbles are located on three mutually orthogonal straight lines. In all the cases, one of the bubbles is central, the others are equally-spaced from it on those lines. All the bubbles are initially spherical with a radius of 3 ?m. Room conditions are considered, the frequency of the wave is 20 kHz, its amplitude is 1.2 times the static liquid pressure. A mathematical model is used, in which the liquid is assumed weakly compressible, the bubbles being homobaric. It is shown that in each configuration of the bubbles the influence of their interaction on their radial dynamics is insignificant. In each configuration, the central bubble remains stationary, while the others move to it at a speed equal for a fixed configuration. At transition from a linear configuration to a planar one and from a planar configuration to a spatial one, the bubble motion speed increases. In all the cases, the deformations of the central stationary bubbles are smaller than those of the rest. Among the central bubbles, the bubble in a planar configuration is deformed most.

The influence of the surface tension of the liquid on bubble’s acoustic scattering

In this situation, the influence of surface tension of liquid on the bubble’s acoustic scattering is studied when the surface tension of liquid is equivalent to the static pressure of liquid. The continuity equation of velocity and pressure in the bubble’s surface is established, and the bubble’s surface tension of liquid is introduced into the continuity equation. We got the scattering coefficient and the scattering sound power of a single bubble in a symmetric vibration mode, and further deduced the equivalent incident sound field in the case of multi-bubble conditions. Numerical analysis shows that spherical bubble radius is about 10-6m when the surface tension equivalent to the liquid static pressure, in this case, the influence of bubble’s surface tension of liquid on the scattering coefficient and the scattering sound power of the single bubble can be shown when the angular frequency of the driving acoustic pressure is less than 105 rad/s. In the case of multiple bubbles, it will have a greater impact on the sound pressure amplitude of the equivalent incident sound field. While the influence will not appear clearly if the angular frequency of the driving acoustic pressure is bigger than 105 rad/s. For the acoustic scattering problem of bubbles, it bases on the specific issue to choose whether the surface tension of liquid should be taken into consideration.

Modeling of the influence of cavitation on petroleum hydrocarbon cracking

It is shown that axial, radial, and peripheral velocities of feed material in centrifugal vortex chamber pronouncedly differ in magnitude. The full velocity is high and attains 43 m/sec on the vortex surface. It is concluded that the cavitation region must be on the vortex surface itself, where indeed cracking of hydrocarbons intensifies. The parameters of the cavitaiton region are determined from the static liquid pressure at all points of the cavitation apparatus. The distribution of static pressure of the liquid in the centrifugal vortex chamber has a complicated pattern: the cavitation region represents a hollow truncated cone, inside which occurs a cylindrical steam vortex. Formation of a turbulent layer expands the cavitation region, the shape and size of which are calculated from the parameters of a real centrifugal chamber.

Bubble-Induced Water Hammer and Cavitation in Microchannel Flow Boiling

While microchannel flow boiling has received much research attention, past work has not considered the impact of acoustic waves generated by rapidly nucleating bubbles. The present work provides a theoretical framework for these pressure waves, which resembles classical “water hammer” theory and predicts a strong influence on bubble nucleation rates and effective convection coefficients. These pressure waves result directly from confinement in microchannel geometries, reflect from geometrical transitions, and superimpose to create large transients in the static liquid pressure. Feedback from the pressure waves inhibits bubble growth rates, reducing the effective heat transfer. Pressure depressions generated by the propagating pressure pulses can cause other bubbles to grow at lower than expected wall temperatures. The additional nucleation enhances heat transfer over short times but increased flow instability may inhibit heat transfer over longer periods. The limited quantitative measurements available in the literature indicate confined bubble growth rates in microchannels are significantly lower than those predicted by the classical Rayleigh–Plesset equation. The present model predicts confined bubble growth rates to within ± 20%. A nondimensional number indicative of the relative magnitude of the water hammer pressure to bubble pressure is proposed to characterize the transitions from conventional to microchannel flow boiling.

Gas−Liquid Mass Transfer in Benchscale Stirred TanksFluid Properties and Critical Impeller Speed for Gas Induction

This work is concerned with the gas−liquid mass transfer in stirred tanks with gas-inducing impellers. Experiments were performed to determine the critical impeller speed for the onset of gas induction and the mass-transfer group kLa, using water, n-hexadecane, toluene, acetone, and sunflower oil at various temperatures as liquids and hydrogen and nitrogen as gases. The use of different liquids and gases allowed the influence of fluid properties on the mass transfer to be studied. Special emphasis is on reducing the experimental effort in downscaling, i.e., the use of benchscale autoclaves to mimic industrial conditions. In benchscale tanks, the capillary pressure is significant, with respect to the static liquid pressure at the impeller, and must be taken into account to describe the critical impeller speed for gas induction. Downscaling implies relatively low mass-transfer rates, which can be achieved by operating close to the critical impeller speed. The critical impeller speed must be included in models for the mass-transfer rate. Our data set of kLa values was best described by a dimensionless correlation, in which a Froude group (based on the stirrer speed N and the critical stirrer speed Ncr) was used to account for the gas-induction rate, together with the Reynolds number and Schmidt number, to account for turbulence intensity and fluid properties.

Study on Dynamic Buckling Behavior of a Cylindrical Liquid Storage Tanks under Seismic Excitation (1st Report, Effects of Liquid Pressure on Elephant Foot Bulge)

When a thin walled cylindrical liquid storage tank is exposed to a very large seismic base excitation, buckling phenomena may be caused such as bending buckling where diamond buckling pattern or elephant foot bulge pattern will be found at the bottom portion, and shear buckling at the middle portion of the tank. In this study, dynamic buckling tests were performed using scale models of thin cylindrical liquid storage tanks for the nuclear power plants. The input seismic acceleration was increased until the elephant foot bulge occurred and the vibrational behavior before and after buckling was investigated. And the effects of static and dynamic liquid pressure on the bending buckling patterns and the buckling critical force was investigated by fundamental tests using small tank models.

Asymptotically exact dispersion relations for collective modes in a confined charged Fermi liquid

Using general local conservations laws we derive dispersion relations for edge modes in a slab of electron liquid confined by a symmetric potential. The dispersion relations are exact up to $\lambda^{2} q^{2}$, where $q$ is a wave vector and $\lambda$ is an effective screening length. For a harmonic external potential the dispersion relations are expressed in terms of the {\em exact} static pressure and dynamic shear modulus of a homogeneous liquid with the density taken at the slab core. We also derive a simple expression for the frequency shift of the dipole (Kohn) modes in nearly parabolic quantum dots in a magnetic field.

2026 地震荷重による座屈挙動における液圧の影響

It has been known that the buckling behaviors which occur at the lower part of tank depend on the ratio of hoop stress due to internal static liquid pressure to yield strength. The AIJ guideline for structural design of fluid storage tanks has considered this characteristics. We noticed dynamic effects of the internal liquid pressure on buckling behavior under seismic loading and performed static and dynamic experiments using thin-walled cylindrical tanks. We verified the effects of dynamic liquid pressure on the buckling behavior.

Nonlinear hydroelastic vibration of a cylindrical tank with an elastic bottom containing liquid-analysis using harmonic balance method

Theoretical analyses and experimental studies have been carried out on the non-linear hydroelastic vibration of a cylindrical tank with an elastic bottom. In this paper, nonlinear axisymmetric free vibration analysis of the bottom plate of the tank, coupled with that of the liquid contained within it, is presented by means of the harmonic balance method. In the analysis, the effect of an in-plane force in the plate due to static liquid pressure is taken into account. The effect of the liquid on the non-linearity of the backbone curve of the super-harmonic and the sub-harmonic resonances as well as the principal resonance of both sloshing- and bulging-type responses was clarified, and it was found that with an increase of liquid height, the non-linearity with a hard-spring type of the bottom plate decreased in degree, and became close to linear characteristics. The influence of the bottom plate motions on the free surface response amplitude in the first bulging-type resonance region was also investigated.

Mechanism of Wave Excitation on a Liquid Metal Surface Submerged in an Intermittent Alternating Magnetic Field.

In order to increase an interfacial area for the promotion of mass transfer in refining processes, a new method exciting surface wave on a molten metal has been proposed in the way introducing an intermittent alternating magnetic field with the stepwise change of amplitude. For estimating the mechanism of the wave excitation on a metal surface and the value of an excited interfacial area, the surface wave behavior on a liquid gallium was measured by use of a laser level sensor by changing intermittent frequency, f i , and duty, D. At lower intermittent frequency compared with the natural frequency of a liquid metal, the change in the magnetic amplitude excited surface motion on an equilibrium surface which could have been formed by the continuous imposition of each magnetic amplitude as a result of the balance between an electromagnetic pressure and a static liquid pressure. When the intermittent frequency is adjusted to the neighborhood of the natural frequency, descending of free surface in the wall vicinity takes place accompanying with increase in the magnetic amplitude and excites surface motion. When the intermittent frequency coincides with the natural one, a free surface area increases remarkably.

FREE VIBRATION ANALYSIS OF CYLINDRICAL TANKS PARTIALLY FILLED WITH LIQUID

A simple but effective modal solution based on the underlying ideas of the hierarchical finite element method is presented for evaluating the free vibration characteristics of vertical, thin, circular, cylindrical shells, partially or completely filled with liquid and subjected to any variationally consistent set of boundary conditions on the lower and upper boundaries. Effects of static liquid pressure, in-plane inertias and liquid free surface motions are taken into account. The solution of the shell problem is obtained through a procedure in which Sander's shell equations are transformed into a new system of first order ordinary differential equations which are solved by the Galerkin error-minimization procedure. The system variables are those quantities which appear in the boundary conditions on a rotationally symmetric edge of a cylindrical shell. The liquid is taken as non-viscous and incompressible, and the coupling between the deformable shell and this medium is taken into account. The solution for the liquid velocity potential is assumed as a sum of two sets of linear combinations of suitable harmonic functions which satisfy Laplace equation and the relevant boundary conditions. This procedure leads to a determinantal equation for the determination of the shell and liquid natural frequencies and the associated mode shapes. Application of the method to a few selected cases and comparisons of the numerical results with those obtained by other theories and from experiments are found to be good and demonstrate the effectiveness and accuracy of the present methodology.

Non-linear hydroelastic vibration of a cylindrical tank with an elastic bottom containing liquid-III. Non-linear analysis with Ritz averaging method

Theoretical analyses and experimental studies have been carried out on the non-linear hydroelastic vibration of a cylindrical tank with an elastic bottom. In this paper, non-linear axisymmetric free vibration analysis of the bottom plate of the tank, coupled with liquid contained, is presented by means of the Ritz averaging method. In the analysis, the effect of an in-plane force in the plate due to the static liquid pressure is taken into account. The effect of liquid contained on the non-linearity of the backbone curve of the principal resonance of both sloshing- and bulging-type responses was clarified, and it was found that with increase of the liquid height, the non-linearity with a hard-spring type of bottom plate decreased in degree, and in fact became close to linear characteristics. The effect of elastic stiffness of the foundation on the bottom plate response was also clarified.

Free vibration of a clamped-free circular cylindrical shell partially submerged in a liquid

Theoretical analysis and experimental study have been carried out on the free vibration of a thin cantilever cylindrical shell partially submerged in a liquid. In the analysis, the shell is assumed to be submerged in a rigid cylindrical container with finite diameter. Considering the effect of static liquid pressure, coupled bulging-type natural frequencies were calculated for various system parameters, i.e., thickness ratio, aspect ratio, density ratio, radius ratio, material parameter, and liquid height. The effect of liquid height outside the shell on the bulging-type natural frequency and on the mode shape of vibration was found to be remarkable for a thinner and longer shell. The results are summarized in the form of engineering design data from which one can easily presume the natural frequency of a given shell partially submerged in a liquid. To confirm the accuracy of the theoretical analysis, experimental study was conducted by using two test cylinders made of polyester film. Excellent agreement between theoretical results and experimental ones was demonstrated.