Internal Pressure Changes Research Articles

Verification and spatial mapping of TRPV1 and TRPV4 expression in the embryonic and adult mouse lens

The transient receptor protein vanilloid channels, TRPV1 and TRPV4, have recently been shown to be mechanosensors in the ocular lens that act to transduce physical changes in lens volume and internal hydrostatic pressure into the activation of signalling pathways in lens epithelial cells. These pathways in turn regulate ion and water transport to ensure that the optical properties of the lens remain constant. Despite the functional evidence that implicate the roles of TRPV1 and TRPV4 in the lens, their respective cellular expression patterns in the different regions of the lens has to date not been fully characterised. Using Western blotting we have confirmed that TRPV1 and TRPV4 are expressed throughout all regions (epithelium, outer cortex, inner cortex/core) of the adult mouse lens. Subsequent immunolabeling of lens cryosections confirmed that TRPV1 and TRPV4 are expressed throughout all regions of the lens, but revealed differentiation-dependent differences in the subcellular expression of the two channels in the different regions. In the epithelium and outer cortex, intense TRPV1 and TRPV4 labeling was predominately associated with the cytoplasm. In a discrete zone in the inner cortex, labeling for both proteins was greatly diminished, but could be enhanced by incubating sections with the detergent Triton X-100 to reveal TRPV1 and TRPV4 labelling that was associated with the membrane. This suggests that in this region of the lens there is a potential interacting protein that masks the binding of the TRPV1 and TRPV4 antibodies to their respective epitopes in the lens inner cortex. In the core of the lens, which contains the embryonic nucleus, TRPV1 and TRPV4 labelling was associated exclusively with fibre cell membranes. This labelling in the lens core of the adult mouse lens appeared to originate in early development as a similar membrane labelling was observed at embryonic day 10 (E10) of the cells in the lens vesicle that subsequently forms the embryonic nucleus in the adult lens. During subsequent stages of embryonic development TRPV1 and TRPV4 remained membranous in the inner cortex and core, while showing labelling that was associated with the cytoplasm in the superficial outer cortical region. The extent of cytoplasmic labelling for TRPV4, but not TRPV1, in this cortical region could however be dynamically regulated by cutting the zonules that normally attach the lens to the ciliary body. We have shown an early onset and continuous expression of TRPV1 and TRPV4 across all lens regions, and that TRPV4 can be dynamically trafficked into the membranes of differentiating fibre cells, results that suggests that these mechanosensitive channels may also be functionally active in lens fibre cells.

Optical microresonator in form of hollow bottle for the measurement of hydrostatic pressure: A theoretical study of its sensitivity

In this research, we report the theoretical study of an optical microresonator in form of hollow bottle for the measurement of hydrostatic pressure in microfluidics. The proposed device bases its operating principle on the excitation of the resonant modes WGMs that are confined to the interior of the optical cavity through the evanescent coupling of the light from the outside. The analytical study developed to determine the sensitivity of the device to changes in internal pressure in the hollow micro-bottle, is developed from a layer model with application of boundary conditions in the problem, where it is necessary to consider the excitation of the transverse modes WGMs and the elastic-optical effect produced by the internal pressurization of the resonant cavity. In the investigation we have concluded that the theoretical results present a good approximation with the experimental results using the layer model with which it is possible to optimize the design of this type of devices to improve the sensitivity for the measurement of the hydrostatic pressure in microfluidics.

On Gas Ingression of Hermetic Packages

In this paper, a closed-form mathematic equation that governs gas ingression of hermetic packages is derived from first principles and applied to moist air and water vapor ingression conditions. The equation models internal gas partial pressure change as a function of time, external conditions, and package characteristics. The equation provides the theoretical basis for direct comparisons of ingression behaviors of different gases into hermetic packages. Comparing the rates of internal air pressure increase due to air ingression and water vapor partial pressure buildup due to water vapor ingression, the authors theorize that vacuum decay may present a greater challenge to the performance of microelectromechanical systems (MEMS) devices within hermetic packages than that of water vapor content induced corrosion failures. This paper also examines gas ingression of hermetic enclosures with multiple layers of seals.

Springback Coefficient Research of API X60 Pipe with Dent Defect

Dent is a common form of defect on oil and gas pipeline. Some dents will undergo elastic or plastic recovery due to changes in internal pressure, also known as springback. To analyze the springback law of an API X60 pipeline with a dent defect, the secondary development technology of finite element software ABAQUS was used for parametric modeling of a dented pipeline. Using this model, the effects of various factors (wall thickness, internal pressure, indenter size, dent location, and dent depth) on the springback coefficient of a dented pipeline were analyzed. The significance of each factor was analyzed by combining an orthogonal experimental design with the Grey correlation degree. Finally, nonlinear regression analysis was used to obtain formulas for the springback coefficient as a function of the influential factors. The results show that the springback coefficient of the dented pipeline after pressurization was between 0.15 and 0.65, and the factor that had the largest effect on the springback coefficient was the dent location. The springback coefficient of the dented pipeline after de-pressurization was between 1.1 and 1.5, and the factor that had the largest effect on the springback coefficient was the internal pressure. The formulas that relate the springback coefficient and various influential factors can be used as a reference for estimating the springback of dented pipelines.

Flow transportation inside shale rocks at low-temperature combustion condition: A simple scaling law

The gas flow inside the shale undergoes a complicated process from continuum-flow to Knudsen diffusion during combustion. In this study, a shale sample obtained from Shanxi province with burial depth of 643 m was combusted at a constant temperature to study the transient internal pressure variation. In the beginning, a cylinder-shaped shale was combusted above an electric heater at a constant temperature 450 °C. The transient internal pressures and surface temperatures of the shale sample were recorded every 15 s. With the thermal wave propagating from the electric heater to the top of shale, the shale surface temperature gradually increased. The pressure inside the sample was quickly built up because of the thermal cracking of kerogen. It reached a peak value of 12,000 Pa. Afterwards, the pressure gradually declined with the improvement of the permeability of the shale. By the observations during the experiment, a combustion model based on the scaling power law was used to simulate the transient internal pressure changes of a cylinder shaped shale sample during the combustion process. The simulated results showed a good agreement with experimental data. Based on the pressure variation data, it was found that not only the original trapped/storage gas (free state gas, adsorbed state gas, and dissolved state gas) but also the thermal cracking hydrocarbon gases produced from kerogen could be extracted from tight shale formation for gas recovery. Thus, combustion can further improve the production rate of gas from shale reservoirs.

Solitary Waves to Assess the Internal Pressure and the Rubber Degradation of Tennis Balls

Rubber is a material present in many commodities, including tennis balls. The characteristics of tennis balls are specified by the International Tennis Federation and are evaluated using standard tests that are too cumbersome to be staged easily and quickly. In this article we present an experimental method based on the propagation of highly nonlinear solitary waves (HNSWs) to determine the internal pressure of tennis balls and to estimate rubber degradation. HNSWs are compact waves that can form and travel in a closely-packed assembly of systematically arranged particles that generally interact according to the Hertz contact law. In the study presented here, we developed a model that predicts the internal pressure of tennis balls and estimates rubber degradation by observing the waves propagating within a chain in contact with the ball to be estimated. The model was validated experimentally, by testing 18 identical balls played over a few weeks period. We found that the dynamic interaction between the waves and the rubber can successfully detect changes in internal pressure and bouncing characteristics and that these changes were barely detected using a conventional rebound test. In the future, the findings of this study may be expanded to characterize any rubber of any shape.

Precise application of Traditional Chinese Medicine in minimally-invasive techniques

Precise application of Traditional Chinese Medicine in minimally-invasive techniques

Heat and mass transfer, shrinkage, and thermal protein denaturation of kuruma prawn (Marsupenaeus japonicas) during water bath treatment: A computational study with experimental validation

Excessive shrinkage of processed food lowers its perceived quality by consumers, and therefore should be avoided. This study aims to clarify the multiphysics involved in the shrinkage of prawn during heating. A model that describes changes in moisture content of prawn due to pressure-driven water transport was reported according to Darcy's law. The transport model for the heating process included a stress-strain analysis (a structural mechanics model) coupled to a virtual work principle, which is applicable to a body undergoing shrinkage in two dimensions. Simultaneous calculation of changes in internal pressure and thermal protein denaturation (TPD, using a non-isothermal kinetics method) was used to describe the physics behind shrinkage. Temperature, moisture, pressure, as well as TPD profiles and distributions were calculated, and were validated with measured results. Results indicated that shrinkage was delayed due to slow rate of water release, which promoted the increment in internal pressure. This phenomenon, in combination with actin denaturation, resulted in dramatic water release and volumetric shrinkage. The proposed model improves the understanding of the shrinkage phenomena of prawn during heating and has the potential to contribute in the reduction of food quality losses associated with shrinkage and water release.

Pressure measurement as a tool to identify moisture transport mechanisms in convective drying of non-shrinking material

The drying process is one of the most important stages in the production of building materials. The choice of the drying method affects the chemical and physical properties of the final product. The aim of this research is to measure and analyze the dynamic changes of internal pressure in non-shrinking, porous material during convective drying. In this work the problem will be discussed with special attention to the behavior of rewetted plaster. A commercial gypsum of company PIOTROWICE II (Alpol brand), typically used in construction and decorative plastering was applied. Gypsum was mixed with water in recommended proportion of 0.6 water/gypsum and drying experiments were performed at 50°C. The changes in sample overall mass as well as pressure and material temperature on the midpoint of sample axis were monitored. On the basis of the obtained experimental data of axial pressure, it is possible to perform a more detailed analysis of mass and heat transfer mechanisms than based on the drying kinetics alone. The pressure trends in the sample allow one to determine the moment of transition from the first to the second drying period, without the need to determine the kinetics of drying. The element of novelty consists of using a direct internal pressure measurement to provide information on the variation of the actual drying rate and mass transfer mechanisms.

Finite Difference Simulation of Implosive Collapsing for Aluminum Spherical Shell

Implosive collapsing for spherical metal shells is a kind of dynamic compressing method, in which high pressure and high compression degree of materials can be attained. In present work, the dynamic process of implosive collapsing for spherical metal shells was regard as spherical symmetry ideally, so one-dimensional spherical symmetric fluid dynamics conservation equations were established, and the finite difference schemes for solving these equations were given. An aluminum spherical shell was assumed, whose inner radius is 4cm and thickness is 2 cm. In numerical simulation, initial centripetal velocities (800, 1000 and 1200 m/s) were used to make aluminum spherical shell collapse. The simulation results show that during the process of implosive collapsing, the material exhibits a compression-expansion-compression pulsation process, and the internal pressure changes and distribution are consistent with the theoretical expectations. The simulation results can be used as a reference for relevant analysis.

Evaluation of Building Internal Pressure Change Caused by Tornado Approach

Evaluation of Building Internal Pressure Change Caused by Tornado Approach

Ground deformation source model at Kuchinoerabu-jima volcano during 2006\u20132014 as revealed by campaign GPS observation

We analyzed campaign Global Positioning System observation data in Kuchinoerabu-jima during 2006–2014. Most benchmarks located around Shin-dake crater showed crater-centered radial horizontal displacements. Horizontal displacements at western rim of the Shin-dake crater were tended to be larger compared to those at eastern rim. In addition, benchmark KUC14 which locates near the cliff at Furu-dake showed westward horizontal displacement rather than crater-centered radial (southward) one. Meanwhile, small displacements were detected at the benchmarks located at the foot of Kuchinoerabu-jima. We modeled the observed displacements applying a finite element method. We set entire FE domain as 100 × 100 × 50 km3. We set top of the domain as a free surface, and sides and bottom to be fixed boundaries. Topography was introduced in the area within Kuchinoerabu-jima using digital elevation model data provided by Kagoshima prefecture and elevation information from Google earth, and elevation of the outside area was assumed to be sea level. We assumed a stratified structure based on a one-dimensional P-wave velocity structure. We applied a vertical spheroid source model and searched optimal values of horizontal location, depth, equatorial and polar radiuses, and internal pressure change of the source using the forward modeling method. A spherical source with a radius of 50 m was obtained beneath the Shin-dake crater at a depth of 400 m above sea level. The internal pressure increase of 361 MPa yields its volume increase of 31,700 m3. Taking effects of topography and heterogeneity of ground into account allowed reproduction of overall deformation in Kuchinoerabu-jima. The location of deformation source coincides with hypocenters of shallow volcano-tectonic (VT) earthquakes and the aquifer estimated from a two-dimensional resistivity model by audio-frequency magnetotellurics method. The obtained deformation source may be corresponding to the pressurized aquifer, and shallow VT earthquakes and demagnetization may be caused by pressure and strain accumulation in the rocks around the aquifer. Applying the obtained spherical source to the tilt change before August 3, 2014 eruption, we found that 520 m3 of volcanic materials were supplied toward shallower in 1.5 h before the eruption. The depth and volume change of deformation source before May 2015 eruption detected by precise leveling surveys is deeper and two orders of magnitude greater compared to that before August 2014 eruption.

Fabrication of Hollow Silica Microspheres with Orderly Hemispherical Protrusions and Capability for Heat-Induced Controlled Cracking.

Hollow silica microspheres with orderly protrusions on their outer and inner surfaces were fabricated in three simple steps: (1) suspension polymerization of a polymerizable monomer containing silica nanoparticles to obtain polymeric microspheres with a layered shell of silica particles; (2) sol-gel reaction of tetraethoxysilane (TEOS) on the surface of the microspheres to connect the silica nanoparticles; (3) removal of polymer core by calcination. The shell composed of silica-connected silica nanoparticles remained spherical even after calcination, and the characteristic surface morphology with protrusions were obtained on both inner and outer surfaces. Measurements of the mechanical strength revealed that the compression modulus of the hollow microspheres increased with increasing thickness of the silica layer, which could be controlled by changing the concentration of TEOS in the sol-gel reaction. Rapid heating of the hollow silica microspheres with the thin silica-connected layer led to silica shell cracking, and the cracks were mostly observed in the connecting layer between the silica nanoparticles. The stress was probably concentrated in the connecting layer because of its lower thickness than the nanoparticles. Such characteristic of the hollow microspheres is useful for a capsule with capability for heat-induced controlled cracking caused by internal pressure changes.

Problems in the implementation of the control system for vertical reactions of vehicle wheels

One of the new active safety systems of the automobile is a system for stabilizing the vertical reactions of the wheels when moving along a periodic profile. The effectiveness of this system largely depends on the success of measuring the values of the vertical reactions of the wheels of the vehicle in motion. The possibility of solving this problem is considered in the article. As a first method for determining the radial reaction in a tire, the method for estimating the radial force from the change in internal pressure in it is considered. Theoretical analysis of this problem based on solving the simplest models, as well as more advanced models using the finite element method, is presented in the article. Another method for determining the radial force in the tire is to measure the radial deformation of the tire in the area of the contact spot. Two methods for determining radial deformation of a tire are considered in the article. One way is to use laser technology. The laser sensor is fixed to the rim of the vehicle wheel, which ensures a constant measurement of radial deformation at one point of the rotating tire. The use of such a device in the system of stabilizing the vertical reactions of the wheels of the automobile is almost impossible, because the frequency of the desired signal is too small. A more advanced version of the measuring device with a gyroscope ensures the continuity of the direction of the laser beam at one point - the center of the contact spot. This ensures the continuity of measuring the radial deformation of the tire during the movement. Another way is to use an annular chamber with a fluid supported on a ring like a ring fixed on the rim of a so-called “safe” wheel. Increasing the pressure in the chamber during radial deformation of the tire makes it possible to evaluate it. Another method of continuous measurement of radial force on the wheel is associated with performing measurements of the vertical acceleration of the center of the wheel and the total force transferred by the suspension to the wheel of the vehicle.

Experimental Analysis of Thermal Runaway in 18650 Cylindrical Li-Ion Cells Using an Accelerating Rate Calorimeter

In this work, commercial 18650 lithium-ion cells with LiMn2O4, LiFePO4, and Li(Ni0.33Mn0.33Co0.33)O2 cathodes were exposed to external heating in an accelerating rate calorimeter (es-ARC, Thermal Hazard Technology (THT), Bletchley, UK), to investigate the thermal behavior under abuse conditions. New procedures for measuring the external and internal pressure change of cells were developed. The external pressure was measured utilizing a gas-tight cylinder inside the calorimeter chamber, in order to detect the venting of the cells. For internal pressure measurements, a pressure line connected to a pressure transducer was directly inserted into the cell. During the thermal runaway experiments, three stages (low rate, medium rate, and high rate reactions) were observed. Both the pressure and temperature change indicated different stages of exothermic reactions, which produced gases or/and heat. The onset temperature of the thermal runaway was estimated according to the temperature and pressure changes. Moreover, the different activation energies for the exothermic reactions could be derived from Arrhenius plots.

Temperature Induced Fracturing of Rock Salt Mass

During the operation of gas storage caverns in rock salt mass the internal pressure changes during filling and withdrawal phases. Additionally temperature variations occur versus operation time. During withdrawal phases the temperature decreases which can lead to stress states in tensile regions at the cavern wall. Because the tensile strength of rock salt is relatively low compared to its compressive strength it is likely that tensile stresses lead to discrete fractures orthogonal to the direction of the tensile stresses.If fractures of this kind are created – whether vertical or horizontal – the gas will penetrate into the fracture at the relevant pressure and further extend the length of the fractures under certain circumstances. There are currently no theoretical approaches describing the manner in which the fractures might propagate into the not by temperature changes influenced rock salt mass during repeated cyclic pressure changes. This aspect is topic of prospective research.Salt caverns cannot be entered but only explored by sonar measurements, with which it is not possible to detect tensile fractures at the cavern wall. Within this paper examples from mining configurations will be shown where temperature changes lead to tensile fractures in the surrounding rock salt. These fractures have been well mapped while the temperature development is well documented.The paper deals with recalculations under consideration of different salt properties of the temperature distributions and the resulting stress state in the surrounding rock salt mass. The stress calculation results and the consequences for the dimensioning of natural gas caverns are going to be discussed and assessed.

The Research on the New Type of Belt Conveyor Barometric Real-time Detection Device Based on the SQL Server

This paper analyzes the causes of the belt conveyor tear accident and the application of the existing laceration resistant real-time monitoring technology. A new real-time detection scheme is put forward as a result of the application of wireless information transmission based on zigbee technology, and the improvement of the conveyer belt structure. The working condition of belt conveyor can be judged by the detection of conveyor belt gasbag internal pressure changes with the database default values in the SQL Server database. The results show that with the ability of data-collection and analysis as well as the management of the data base, the system can work efficiently when running deviation, puncture or tear happens.

Evaluating the Effect of Micropump© Position, Internal Pressure and Doxorubicin Dosage on Efficacy of Pressurized Intra-peritoneal Aerosol Chemotherapy (PIPAC) in an Ex Vivo Model.

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a novel clinical approach to the treatment of peritoneal carcinomatosis. A well-established, not anatomic ex vivo PIPAC model was used to investigate the influence of changes in internal pressure, distance of the Micropump(©) (MIP) to the distributing surface and the drug concentration on the penetration depth of doxorubicin in the target tissue. Doxorubicin was aerosolized in an ex vivo PIPAC model using a hermetic container system mimicking the abdominal cavity. Fresh post-mortem swine peritoneum was cut into proportional samples. Tissue specimens were spatially placed at 4 different spots within the box: P1, on the distributing surface of the box, directly opposite to MIP; P2, on the side wall of the box; P3, on the ceiling of the box; P4, on the distributing surface with a partial cover. Impact of changes in the following parameters were analyzed and compared with clinically established values (CEVs) at our center: pressure (CEV=12 mmHg), distance of the MIP from the distributing surface (CEV=8 cm) and doxorubicin concentration (CEV=3 mg/50 ml). In-tissue doxorubicin penetration depth was measured using fluorescence microscopy on frozen thin sections. Tissue positioning in the box had a significant impact on drug penetration after PIPAC with CEV. Under CEV conditions, the highest drug penetration depth was observed in the tissue placed on the distributing surface directly opposite to the MIP (P1: 351 μm, P2: 77 μm, P3: 66 μm, P4: 34 μm). A closer positioning of the MIP lead to a significantly higher mean depth penetration of doxorubicin in the P1 in contrast to other samples in which a reduced drug penetration was observed (1 cm vs. 8 cm distance from MIP to the distributing surface, P1 at 1 cm: 469 μm vs. P1 at 8 cm: 351 μm, p<0.0001; P2 at 1 cm: 25 μm vs. P2 at 8 cm: 77 μm, p<0.0001; P3 at 1 cm: 21 μm vs. P3 at 8 cm: 66 μm, p<0.001; P4 at 1 cm: 13 μm vs. P4 at 8 cm: 39 μm, p=0.021). Higher doxorubicin concentrations led to a highly significant increase of drug penetration in P1 (1 cm vs. 8 cm, p<0.0001), but only a little significant increase in other samples. An increase of internal pressure did not show a significant increase in penetration depth of doxorubicin. Our ex vivo data suggest that a higher pressure does not increase the penetration deepness of doxorubicin. Higher drug dosage and a closer positioning of the MIP toward the target lead to a higher penetration of doxorubicin within the samples. A more homogeneous penetration within all targets cannot be achieved by changing drug concentration, position of the nozzle or pressure increase.

밸브시험기의 구조개선 및 신제품 개발

This research aims to evaluated the structure improvement and new product development of valve tester. A valve tester was redesigned for structure improvement and new product development using 3-D design program CATIA. In addition, behavior analysis was conducted on the modeled valve tester using the ANSYS program. The total deformation, stress and strain were obtained by the internal pressure change. This result was applied to the new product development of valve tester.

Experimental Analysis of Thermal Runaway in 18650 Cylindrical Li-Ion Cells Using an Accelerating Rate Calorimeter

In this work commercial 18650 lithium ion cells with LiCoO2 and LiMn2O4 cathodes were exposed to external heating in an Accelerating Rate Calorimeter (es-ARC, THT Company) in order to investigate the thermal behavior under abuse conditions. During the experiments the temperature and the internal pressure changes of the cells were measured in the ARC. Furthermore, external pressure changes were measured in order to detect venting of the cells. Before the measurement the cells were fully charged and the so-called Heat-Wait-Seek method was applied. This procedure starts by heating the sample in small incremental steps. At the end of each step the calorimeter “waits” if the battery is generating heat that can be measured by a temperature rise (so called "seek" step). When self-heating of the cell is detected, the ARC switches to the adiabatic mode in which the temperature of the calorimeter follows instantaneously the surface temperature of the cell, i.e. the cell cannot exchange heat with the surroundings anymore. This procedure is repeated until a thermal runaway occurs. For the external pressure measurements, the cell was placed in a gas-tight cylindrical compartment inside the calorimeter chamber. This compartment was equipped with an outlet where a pressure line is connected with a pressure sensor. In contrast to the external pressure measurement for internal pressure measurements this pressure line was directly inserted into the cell. Therefore, a suitable place had to be found by using images from X-Ray Tomography. In a second experiment a current profile was applied to the cell with maximal C-rate and cycled until a thermal runaway occurs. During these experiments again the internal and external pressure was measured as well as the cell temperature. In addition the heat capacity was measured to calculate the heat of reaction. From the results of the thermal runaway experiments, three stages (low rate reactions stage, medium rate reactions stage and high rate reactions stage) have been observed. Both pressure and temperature change indicated different stages of exothermic reactions, which would produce gases or/and heat. The onset temperature of thermal runaway was estimated according to temperature and pressure changes in the measurements. Moreover, the different activation energies for the exothermic reactions could be derived from Arrhenius plots. Finally, the experimental data were compared with the results of numerical simulations based on an electrochemical-thermal model which was extended with additional source terms in order to describe the exothermic reactions inside the cell during thermal runaway. The experimentally determined activation energies have been used as input parameters for these simulations. It could be shown that the above mentioned reactions stages can also be found in the simulations.