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Compared with the use of expensive pressure-compensating drip tapes, installing pressure regulators (PRs) at the inlet of cost-effective non-pressure-compensating drip tapes is obviously a more economical technology to achieve precision agriculture. However, most drip lateral PRs may not meet the requirements of the design and use of complex drip irrigation systems (hilly or large-scale systems), and there is seldom research on their application in drip irrigation systems, both restricting the promotion of this precision agriculture technology. In this paper, two types of PRs (A- and B-type) for complex drip irrigation systems are proposed, and compared with two conventional PRs (C- and D-type) under 9 different pressure and flow conditions of the drip irrigation system. The main advantage of A- and B-type PRs over conventional PRs is that their outlet pressures are scarcely affected by inlet pressure and flow. Therefore, A- and B-type PRs not only cope with large submain pressure differences, but also guarantee irrigation uniformity CU up to 90% in drip irrigation systems with different drip-tape lengths (flow range: 350-1400 L/h), while CU can be lower than 80% under the same conditions without PRs or using conventional PRs. When designing drip irrigation systems, the use of A- and B-type PRs can allocate greater pressure deviation to the laterals (hv2) to increase the lateral laying length, thus further reducing pipeline network investment. Under the requirements of maximum pressure deviation hv<40%o and submain pressure deviation hv1<20%, the results of hv2 with A-, B-, C-, and D-type PRs were 30%-35%, 30%-37%, 33%-35%, and 21%-27%, respectively. This research provides a device and method that can improve the irrigation uniformity of drip irrigation systems across a wider application range. Based on this research, users can reasonably select the PRs according to different design standards, significantly enhancing the irrigation uniformity of the system in a cost-effective manner. [ABSTRACT FROM AUTHOR]

Abstract Glaucoma, a blinding eye disease with optic neuropathy, is usually associated with elevated intraocular pressure (IOP). The currently available pharmacological and surgical treatments for glaucoma have significant limitations and side effects, which include systemic reactions to medications, patient non-compliance, eye infections, surgical device failure, and damage to the eye. Here, we present Sensor-Actuator-Modulator (SAM), an engineered double mutant version of the bacterial stretch-activated mechanosensitive channel of large conductance (MscL) that directly senses tension in the membrane lipid bilayer of cells and in response, transiently opens its large nonspecific pore to release cytoplasmic fluid. The heterologously expressed mechanosensitive SAM channel acts as a tension-activated pressure release valve in trabeculocytes. In the trabecular meshwork (TM), SAM is activated by membrane stretch caused by elevated IOP. We have identified several SAM variants that are activated at physiologically relevant pressures. Using this barogenetic technology, we have demonstrated that SAM is functional in cultured TM cells, and successfully transduced in vivo in TM cells by use of AAV2/8. Further, it is effective in enhancing aqueous humor outflow facility leading to lowering the IOP in a mouse model of ocular hypertension.

Glaucoma, a blinding eye disease with optic neuropathy, is usually associated with elevated intraocular pressure (IOP). The currently available pharmacological and surgical treatments for glaucoma have significant limitations and side effects, which include systemic reactions to medications, patient non-compliance, eye infections, surgical device failure, and damage to the eye. Here, we present Sensor-Actuator-Modulator (SAM), an engineered double mutant version of the bacterial stretch-activated mechanosensitive channel of large conductance (MscL) that directly senses tension in the membrane lipid bilayer of cells and in response, transiently opens its large nonspecific pore to release cytoplasmic fluid. The heterologously expressed mechanosensitive SAM channel acts as a tension-activated pressure release valve in trabeculocytes. In the trabecular meshwork (TM), SAM is activated by membrane stretch caused by elevated IOP. We have identified several SAM variants that are activated at physiologically relevant pressures. Using this barogenetic technology, we have demonstrated that SAM is functional in cultured TM cells, and successfully transduced in vivo in TM cells by use of AAV2/8. Further, it is effective in enhancing aqueous humor outflow facility leading to lowering the IOP in a mouse model of ocular hypertension. [ABSTRACT FROM AUTHOR]

The present paper provides a brief overview of the existing methods for energy separation and an analysis of the possibility of the practical application of the Hartmann–Sprenger effect to provide quasi-isothermal pressure reduction of natural gas at the facilities within a gas transmission system. The recommendations of external authors are analyzed. A variant of a quasi-isothermal pressure regulator is proposed, which assumes the mixing of flows after energy separation. Using a numerical simulation of gas dynamics, it is demonstrated that the position of the resonators can be determined on the basis of calculations of the structure of the underexpanded jet without taking into account the resonator and, accordingly, without the need for time-consuming calculations of the dynamics of the processes. Based on the results of simulating the gas dynamics of two nozzle–resonator pairs installed in a single flow housing, it is shown that, in order to optimize the regulator length, the width of the passage between the two nearest resonators should be greater than or equal to the sum of diameters of the critical sections of the nozzles. Numerical vibroacoustic analysis demonstrated that the most dangerous part of the resonator is the frequency of its natural oscillations. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cells from different organs in the body experience a range of mechanical and osmotic pressures that change in various diseases, including neurological, cardiovascular, ophthalmological, and renal diseases. Here, we demonstrate the use of an engineered Sensor-Actuator-Modulator (SAM) of microbial origin derived from a mechanosensitive channel of large conductance (MscL) for sensing external mechanical stress and modulating activities of mammalian cells. SAM is reliably expressed in the mammalian cell membrane and acts as a tension-activated pressure release valve. Further, the activities of heterologously expressed SAM in mammalian cells could be modulated by osmotic pressure. A comparison of the mechanosensitive activities of SAM-variants from different microbial origins shows differential inward current and dye uptake in response to mechanical stress exerted by hypo-osmotic shock. The use of SAM channels as mechanical stress-activated modulators in mammalian cells could provide new therapeutic approaches for treating disorders related to mechanical or osmotic pressure.

Currently, when creating the actuators of deep-sea vehicles and other technical facilities, there is a tendency to accommodate the elements of the hydraulic drive outside the durable housing. Such hydraulic systems are subject to the risk of depressurization, which leads to the ingress of working fluid (mineral oils or synthetic working fluids) into seawater and flooding of the hydraulic system's working fluid with seawater. The ingress of the working fluid into seawater leads to the violation of environmental safety, and if seawater enters the internal cavities of the hydraulic system, they may be damaged, which will require long and expensive repair in the future. One of the possible ways to eliminate the listed consequences of depressurization of outboard hydraulic systems is the creation of hydraulic equipment using seawater as a working fluid. The cheapest design of such a regulatory body is the use of shut-off valves with elastic tubular control elements. The research carried out confirmed the possibility of creating low-noise regulators with elastic control elements. These regulators have better vibroacoustic characteristics than spool-type throttles with similar functional characteristics. Preservation of the operating characteristics of regulators with elastic regulating elements when working with working fluids of different viscosities (PGV liquid, mineral oil, tap water) was confirmed. Survivability of a regulator with elastic control elements during long-term tests was confirmed. As a result of the work carried out, research and technological groundwork was obtained that allows creating a device with elastic regulating elements, having a flow differential characteristic that meets modern requirements, a vibroacoustic characteristic that meets advanced requirements and sufficient reliability when working on clean working fluids.

This study is focused on energy harvesting. The goal was to develop a new energy-harvesting system using a pressure regulator and establish an efficient energy flow model within it. The harvested electrical energy can be used as a power source for devices around the regulator, such as primary battery-powered gas meters, thereby enabling battery-free operation. Here, we focus on pressure regulators for LP and city gases, which are used by a vast number of consumers. We systematically modeled complicated energy-conversion processes using the transfer matrix method to maximize the recovered electrical energy. Under normal gas usage conditions, the gas flow is low, and the harvested energy is limited. However, it surpasses the energy supplied by the primary batteries. The results obtained under the actual operational conditions were compared with those calculated using a theoretical model. Within the system, a DC motor and an AC motor were used as generators, and the results were compared. When a DC motor was used as the generator under 0.05 MPa, 0.8 L/m, and maximum power-harvesting load conditions, the harvested power was 0.237 W, which is sufficient to drive the meters. Additionally, the error between the experimental and theoretical results ranged from 2.6% to 4.6%. When an AC motor was used as a generator, the harvested energy was 0.015 W and the error was −14.7%. Utilizing this theoretical model allows for the calculation of the optimal conditions for energy harvesting from various pressure regulators, thereby offering design guidelines for energy-harvesting systems.

The article shows the areas of use of pneumatic protective and regulating devices in the enrichment of gas concentrates. Examples of technological schemes based on the application of pneumatic regulators are given. Reducers of the "after itself" type serve to reduce the pressure of gas supplied from highpressure receivers, a group of cylinders and receivers. The inclusion of such regulators allows you to reduce the inlet pressure to a level corresponding to the characteristics of the compressors or the technological modes of the units. Reducers "to itself" serve to stabilize the pressure in the devices-sources of gas concentrates. When selecting a Ne-He mixture from a number of different types of air separation units into the phase separator (dephlegmator), such regulators are able to ensure the coordinated operation of several units and eliminate the overflow of the mixture and violation of air separation. Reducers "to itself" can perform the functions of preventive protective valves along with typical safety valves. Unlike the latter, regulators "to itself" have greater sensitivity and are able to reduce the pressure in the installation smoothly, without disrupting the technological process. In this case, the regulators are adjusted to 0.2...0.3 MPa below the pressure of the main safety valve. Examples of circuits based on the use of pneumatic regulators in inert gas enrichment systems are given. The case of sampling the mixture directly from the source and feeding it uniformly into the column with increased (relative to the source) pressure is considered. This option involves matching the compressor flow rate with the column performance through the use of periodic compression and receivers. Calculation models allow predicting the change in pressure during the cycle. Depending on the performance of the unit, the minimum volume of the receiver is calculated, which ensures the continuity of the mixture supply to the column. The proposed schematic solutions allow for stable operation of units for the enrichment of inert gas concentrates. [ABSTRACT FROM AUTHOR]

The present paper provides a brief overview of the existing methods for energy separation and an analysis of the possibility of the practical application of the Hartmann–Sprenger effect to provide quasi-isothermal pressure reduction of natural gas at the facilities within a gas transmission system. The recommendations of external authors are analyzed. A variant of a quasi-isothermal pressure regulator is proposed, which assumes the mixing of flows after energy separation. Using a numerical simulation of gas dynamics, it is demonstrated that the position of the resonators can be determined on the basis of calculations of the structure of the underexpanded jet without taking into account the resonator and, accordingly, without the need for time-consuming calculations of the dynamics of the processes. Based on the results of simulating the gas dynamics of two nozzle–resonator pairs installed in a single flow housing, it is shown that, in order to optimize the regulator length, the width of the passage between the two nearest resonators should be greater than or equal to the sum of diameters of the critical sections of the nozzles. Numerical vibroacoustic analysis demonstrated that the most dangerous part of the resonator is the frequency of its natural oscillations.

Abstract The pneumatic vibration isolator (PVI) plays an increasingly important role in precision manufacturing. In this paper, aiming to detect the performance of the pressure regulator in the PVI system, a PVI testing system with a pressure regulator is designed and developed. Firstly, the structure of the pneumatic spring is presented and analyzed, and the nonlinear stiffness is obtained based on the ideal gas model and material mechanics. Then, according to the working principle and continuity equations of ideal airflow, a dynamic model of the PVI system with a pressure regulator is established. Through the simulation analysis, the vibration isolation performance is improved with the efficient and precise pressure regulator. The average values of both the vibration velocity and transmission rate decrease when the vibration is set to 4, 10, 20 and 40 Hz, respectively. The experiments demonstrate the reliability and effectiveness of the pressure regulator. This achievement will become an important basis for future research concerning precision manufacturing.

Among the alternative fuels enabling the energy transition, hydrogen-based transportation is a sustainable and efficient choice. It finds application both in light-duty and heavy-duty mobility. However, hydrogen gas has unique qualities that must be taken into account when employed in such vehicles: high-pressure levels up to 900 bar, storage in composite tanks with a temperature limit of 85 °C, and a negative Joule–Thomson coefficient throughout a wide range of operational parameters. Moreover, to perform a refueling procedure that is closer to the driver's expectations, a fast process that requires pre-cooling the gas to −40 °C is necessary. The purpose of this work is to examine the major phenomena that occur during the hydrogen refueling process by analyzing the relevant theory and existing modeling methodologies. [ABSTRACT FROM AUTHOR]

Here, we describe the development of an organ-on-a-chip platform that enables ex vivo studies under active physio-mechanical stress by applying hydrodynamic and mechanical forces to vascular endothelial cells. Access to current platforms for such studies is hampered by the need for advanced fabrication techniques to create these platforms, and the need for extensive ancillary equipment for their operation. The platform design and fabrication approach reported here aims to improve accessibility of microfluidic technology for ex vivo mechanobiology studies to the broader biomedical research community. Dual-layer lithography was used to significantly reduce the technical expertise and equipment required to create porous, stretchable membranes that serve as the substrate for cells. A cost-effective, portable pressure regulator was created to apply physiologically relevant cyclic stretch (to resemble breathing) across pulmonary endothelial cells grown on the porous membrane. The use of cyclic olefin copolymer sheets helped reduce the total thickness of the microfluidic platform to about 3 mm, enabling fluorescence imaging 'on-chip'. Furthermore, the reversible bond between the cyclic olefin copolymer lid and the rest of the platform allows for exposure of the cells to aerosolized particulates. To validate the capacity to image cells in situ, we obtained subcellular actin images of bovine aortic endothelial cells and human pulmonary aortic endothelial cells 'on-chip'. Overall, we present an accessible microfluidic platform that exposes endothelial cells to physiologically relevant shear and/or cyclic stretch, and allows for post exposure 'on-chip' cell imaging. [ABSTRACT FROM AUTHOR]

The application of expansion turbines at natural gas pressure reduction stations (PRS) is considered in order to recover energy contained in the natural gas. This energy is irretrievably lost at the reduction stations which use the traditional pressure reducer. Expanders allow for the electricity production for PRS own needs and for resale. The paper presents an analysis of the possibility of using turboexpanders at PRS in Poland. Authors performed static simulations for the assumed data sets and dynamic simulations for annual data from selected representative natural gas reduction and measurement stations. Energy balances are presented for the discussed scenarios that compare the energy requirements of natural gas pressure reduction stations which use a classic pressure reducer or turboexpander (TE). Using static simulations, authors investigated whether the use of a turboexpander is economically justified for the case if it is used only to supply the reduction station with electricity. Dynamic analyses were carried out using real data. In addition, static analyses were performed for a natural gas reduction and measurement station using a PEM fuel cell for the production of electricity in a combined gas heating system. At higher inlet temperatures and pressures, the expansion process was more economical due to the lower heat power requirement and the greater amount of produced electricity. The PRS with the turboexpander compared to the PRS with the reducer required the supply of thermal energy which did not allow the PRS to lower operating costs for the assumed prices of heat and electricity. The reduction system with the PEM fuel cell in the combined heating system positively achieved lower operating costs of the PRS (without taking into account the investment costs). Total annual costs for PRS with a reducer was PLN 1,593,167.04, and for PRS with TE + PEM PLN 1,430,595.60—the difference was PLN 108,571.44 in favor of the arrangement with TE and PEM. The payback time should be investigated, although the use of such a system gives the impression of oversizing. An increase in the electricity purchase price and a decrease in the natural gas purchase price may contribute to the investment in the future. [ABSTRACT FROM AUTHOR]

The pneumatic vibration isolator (PVI) plays an increasingly important role in precision manufacturing. In this paper, aiming to detect the performance of the pressure regulator in the PVI system, a PVI testing system with a pressure regulator is designed and developed. Firstly, the structure of the pneumatic spring is presented and analyzed, and the nonlinear stiffness is obtained based on the ideal gas model and material mechanics. Then, according to the working principle and continuity equations of ideal airflow, a dynamic model of the PVI system with a pressure regulator is established. Through the simulation analysis, the vibration isolation performance is improved with the efficient and precise pressure regulator. The average values of both the vibration velocity and transmission rate decrease when the vibration is set to 4, 10, 20 and 40 Hz, respectively. The experiments demonstrate the reliability and effectiveness of the pressure regulator. This achievement will become an important basis for future research concerning precision manufacturing. [ABSTRACT FROM AUTHOR]

The impact of two parameters - the pressure regulator X1 at the nozzle and the speed of the machine X2 for the amount of water flow through the sprinkler (Y, mm) experiment were determined by 8 mm diameter nozzles. The experiment was carried out in the laboratory of “Design of Irrigation and Equipment” used by “Sprinkler’s uniformity distribution measuring equipment” at the School of Engineering and Technology of MULS. In order to determine the rain intensity of low pressure sprinkler nozzle, mathematical statistical methods was used and it was found that the maximum amount of water supplied by the sprinkler nozzle is 1.727 mm/min with a maximum pressure of 30 PSI and a minimum speed is 1 m / min with a minimum flow rate of 0.313 mm/min. At a pressure regulator value of 20 PSI, the speed was a maximum of 3 m/min.

The application of expansion turbines at natural gas pressure reduction stations (PRS) is considered in order to recover energy contained in the natural gas. This energy is irretrievably lost at the reduction stations which use the traditional pressure reducer. Expanders allow for the electricity production for PRS own needs and for resale. The paper presents an analysis of the possibility of using turboexpanders at PRS in Poland. Authors performed static simulations for the assumed data sets and dynamic simulations for annual data from selected representative natural gas reduction and measurement stations. Energy balances are presented for the discussed scenarios that compare the energy requirements of natural gas pressure reduction stations which use a classic pressure reducer or turboexpander (TE). Using static simulations, authors investigated whether the use of a turboexpander is economically justified for the case if it is used only to supply the reduction station with electricity. Dynamic analyses were carried out using real data. In addition, static analyses were performed for a natural gas reduction and measurement station using a PEM fuel cell for the production of electricity in a combined gas heating system. At higher inlet temperatures and pressures, the expansion process was more economical due to the lower heat power requirement and the greater amount of produced electricity. The PRS with the turboexpander compared to the PRS with the reducer required the supply of thermal energy which did not allow the PRS to lower operating costs for the assumed prices of heat and electricity. The reduction system with the PEM fuel cell in the combined heating system positively achieved lower operating costs of the PRS (without taking into account the investment costs). Total annual costs for PRS with a reducer was PLN 1,593,167.04, and for PRS with TE + PEM PLN 1,430,595.60—the difference was PLN 108,571.44 in favor of the arrangement with TE and PEM. The payback time should be investigated, although the use of such a system gives the impression of oversizing. An increase in the electricity purchase price and a decrease in the natural gas purchase price may contribute to the investment in the future.

High-pressure pumps for microfluidic systems typically require high power and have large sizes, which hinder portability of otherwise miniaturized HPLC systems. To solve this, a battery-powered, pneumatic system for pressure-driven chromatography is presented. The system utilizes the stored energy in pressurized gas without consuming any of the gas. As the chromatography liquid flows, the gas in the pressure container expands and its pressure reduces. To compensate for this, a solution is presented with an on-chip microfluidic pressure regulator. The chip contains a microfluidic restrictor where fluid is heated by Joule heating to decrease viscosity, and thus reduce the pressure drop over the restrictor. An 18 V battery driven system with 50 ml N 2 at 51 bar could provide a water flow rate of 55 μ l /min at 32 bar for 67 min with a mean power consumption of 0.2 W. With the regulating microfluidic chip, the pressure stability was 2 mbar, i.e., on pair with high-quality high-pressure syringe pumps. The required gas volume, and hence the total size, is scalable with the desired liquid volume, which makes it suitable for miniaturized systems. [Display omitted] • Battery-powered pump system only requiring 0.3 W. • On-chip pressure regulator compensates for decreasing gas pressure. • Piston separates gas and liquid avoiding any chemical interaction. • Gas does not get consumed and can be reused multiple times. [ABSTRACT FROM AUTHOR]

The impact of two parameters - the pressure regulator X1 at the nozzle and the speed of the machine X2 for the amount of water flow through the sprinkler (Y, mm) experiment were determined by 8 mm diameter nozzles. The experiment was carried out in the laboratory of "Design of Irrigation and Equipment" used by "Sprinkler's uniformity distribution measuring equipment" at the School of Engineering and Technology of MULS. In order to determine the rain intensity of low pressure sprinkler nozzle, mathematical statistical methods was used and it was found that the maximum amount of water supplied by the sprinkler nozzle is 1.727 mm/min with a maximum pressure of 30 PSI and a minimum speed is 1 m / min with a minimum flow rate of 0.313 mm/min. At a pressure regulator value of 20 PSI, the speed was a maximum of 3 m/min. [ABSTRACT FROM AUTHOR]

The expediency of replacement of throttling devices used for low-pressure gas (fuel, starting, etc.) treatment to meet self-needs of plants treating gas for transportation with expansion units was examined as a part of the PJSC Gazprom's energy saving policy of improving energy efficiency of subsidiary companies and organization based on application of innovative technologies and energy-generating equipment. The proposed fuel gas treatment technique will able production of additional amount of eco-friendly "green" energy and reduce thereby the operating cost and enhance energy efficiency of the whole plant. The paper presents a comparative analysis of isenthalpic and isentropic gas expansion by various devices. The proposed gas expansion models were constructed using specialized HYSYS (Aspen Tech) software package for modeling chemical engineering system and allow quantitative estimation of the energy of gas pressure drop. [ABSTRACT FROM AUTHOR]

A pressure regulator in a system of the base shroud failed during service. The pressure regulator is intended to regulate the inlet pressure of 275 to 50 kg/cm2 outlet pressure. The working medium is stated to be nitrogen gas. On disassembly of the system, a brown layer was observed on the seating surface of poppet of the main regulator. A brown layer was also observed on the spring pocket and on the spring end surface which was in contact with the poppet. Metallographic tests and hardness measurement were carried out on the components to reach to the cause of failure. The poppet of the pressure regulator failed to function in service due to rusting of its seating surface by crevice corrosion and partial closure of the holes. The crevices at contact surface between the poppet and the spring seems to have formed by settlement of a stagnant condensed moisture along the surface. Partial closure of the holes was due to the presence of condensed moisture as well as rust. Spring made of AISI 302 austenitic stainless steel did not corrode at all, while poppet made of AISI 420 martensitic stainless steel corroded heavily. [ABSTRACT FROM AUTHOR]

Copyright of Computer Measurement & Control is the property of Magazine Agency of Computer Measurement & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Long-distance gas transfer requires high pressure, which has to be reduced before the gas is conveyed to the customers. This pressure reduction takes place at natural gas pressure reduction stations, where gas pressure is decreased by using gas flow energy for overcoming local resistance, represented by a throttling valve. This pressure energy can be reused, but it is difficult to implement it at small pressure reduction stations, as the values of unsteadiness significantly increase when the gas approaches consumers, whereas gas flow rate and pressure decrease. This work suggests replacing throttling valves at small pressure reduction stations for expander-generator units, based on volumetric expanders. Two implementations are proposed. A mathematical model of gas-dynamic processes, which take place in expander-generator units, was developed using math equations. With its help, a comparison was made of the stability of the operation of two possible control schemes in non-stationary conditions, and the feasibility of using an expander-generator regulator as a primary one for a small natural gas pressure reduction station was confirmed.

Oxygen production centers produce oxygen in high pressure that needs to be defused. A regulator is designed and analyzed in the current paper for medical use in oxygen production centers. This study aims to design a new oxygen pressure regulator and perform an analysis using Finite Element Modeling in order to evaluate its working principle. In the design procedure,the main elements and the operating principles of a pressure regulator are taking into account. The regulator is designed and simulations take place in order to assessthe proposed design. Stress analysis results are presented for the main body of the regulator, as well as, flow analysis to determine some important flow characteristics in the inlet and outlet of the regulator.

Cells from different organs in the body experience a range of mechanical and osmotic pressures that change in various diseases, including neurological, cardiovascular, ophthalmological, and renal diseases. Here, we demonstrate the use of an engineered Sensor-Actuator-Modulator (SAM) of microbial origin derived from a mechanosensitive channel of large conductance (MscL) for sensing external mechanical stress and modulating activities of mammalian cells. SAM is reliably expressed in the mammalian cell membrane and acts as a tension-activated pressure release valve. Further, the activities of heterologously expressed SAM in mammalian cells could be modulated by osmotic pressure. A comparison of the mechanosensitive activities of SAM-variants from different microbial origins shows differential inward current and dye uptake in response to mechanical stress exerted by hypo-osmotic shock. The use of SAM channels as mechanical stress-activated modulators in mammalian cells could provide new therapeutic approaches for treating disorders related to mechanical or osmotic pressure., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

The primary objective of the present study was to identify the problems experienced by agricultural enterprises in Çumra town of Konya province in utilization of PTO shaft-driven field sprayers. Data were gathered through face-to-face questionnaires applied to 119 agricultural enterprises selected by stratified randomized sampling procedure from the town. Present findings revealed that 50.4% of sprayers had a tank capacity of 600 L, 89.9% of tanks were made of plastic material and 26.9% of the sprayers had an operational width of 10 m. Cracks or fractures were reported on boom by 31.9% and on both boom and chassis by 46.2%. About 24.4% indicated that they replaced the nozzles in case of a plug, 52.1% indicated regulator problems on rod, 26% indicated pump problems on pump lid and 91.6% indicated that they replaced at least one part. It was concluded based on present findings that farmers should be trained about utilization of sprayers to change their routines on sprayers. They should perform sprayer maintenance and repairs in accordance with user manual. [ABSTRACT FROM AUTHOR]

• The pressure wave propagation in pressurized thin-walled tubes were investigated. • Numerical models include modeling approach of fluid-structure interaction (FSI). • ALE models validated by experiments were used to examine impact wave propagation. • The results show a complex pressure wave propagation occurs in pressurized tubes. • The finding promotes the ALE should be used for a realistic modeling of the air. The pressurized thin-walled tubes are called as a member of adaptive energy absorbers of which energy absorbing performance can be controlled by variation of internal pressure. In this context, this study numerically investigates the axial impact performance of pressurized thin-walled circular tubes. For the realistic modeling of the compressed air, the ALE model was developed in LS-DYNA, which enabled an opportunity to investigate both pressure wave propagation in pressurized air and fluid-structure interaction effects between tube-wall and air. In addition, the models were run by taking into account both states, whether pressure regulator, which is an adjustable valve to control internal pressure value, was active. To validate the numerical models, the axial impact tests on Aluminum Aerosol cans were carried out using a light gas gun set-up. The results showed that at the onset of impact, a radial pressure wave, as well as an axial pressure one, simultaneously emerged. Whereas a radial pressure wave propagated towards the center from the tube-wall, the other one propagated along the centerline of the tube. Therefore, a complex pressure distribution and wave propagation occurred in the pressurized tubes. The pressure distribution obtained in the model with a pressure regulator revealed different behavior from the corresponding one obtained without pressure regulator. Also, the results showed that there is no distinct interaction between strain energy absorbed by tube-wall and pressure wave propagation although the total absorbed energy of pressurized tubes increases to some extent with the effects of wave propagation in the pressurized medium. [ABSTRACT FROM AUTHOR]

A mathematical model for reducing the pressure of natural gas in a direct acting pressure regulator is developed. It is shown that, if an outlet-inlet pressure ratio typical for practice is lower than a critical value, the pressure reduction process comes down to two stages: partial expansion of gas with throttling in the orifice plate of the pressure regulator and subsequent expansion in its body. The values of the gas temperature in the characteristic sections of the pressure regulator are determined. It is established that the temperature drops at the first stage of pressure reduction and rises as the flow in the pressure regulator body expands and decelerates. A method for minimizing the possibility of formation of gas hydrates in the pressure regulator is proposed. [ABSTRACT FROM AUTHOR]

Abstract Fuel cell vehicles offer significant sustainability benefits by eliminating tailpipe emissions, increasing powertrain efficiency, and utilizing hydrogen that can be supplied from various sources including renewables. A pressure regulator in the hydrogen storage system on a fuel cell vehicle is an important component to ensure that the hydrogen delivery to the fuel cell stack meets the pressure and temperature requirements. A validated model of the regulator can be used to support the product design and optimization of the operating strategy. In this work, a pressure regulator model has been developed to capture the hydrogen discharge behaviors from the compressed hydrogen tank to the fuel cell stack. The focus of the model is to develop the pressure and temperature relationship at the regulator outlet given the inlet conditions from the storage tank. Besides the ideal-gas based derivation for pressure response, the model has used a constant-enthalpy approach to capture the hydrogen temperature increase associated with the pressure drop due to the Joule–Thomson effect. The model was validated with various testing data including hysteresis and dynamic flow conditions, showing satisfactory agreement. The validated model was then used for parametric studies. The modeling results concluded that the regulator inlet temperature has the strongest influence on raising the outlet temperature, while the regulator inlet pressure is an important factor although secondary to the inlet temperature. The comprehensive regulator modeling developed in this work provides the foundation for assessing and optimizing a key dynamic component in the hydrogen storage system. Highlights • A pressure regulator model has been developed to capture the hydrogen discharge behaviors. • The hydrogen temperature increase due to Joule–Thomson effect has been captured. • The model was validated with various hysteresis and dynamic flow conditions. • The regulator inlet temperature has a significant influence on the outlet temperature. [ABSTRACT FROM AUTHOR]

During the natural gas pipeline transportation process, gas stream pressure is reduced at natural gas regulation stations (GRS). Natural gas pressure reduction is accompanied by energy dissipation which results in irreversible exergy losses in the gas stream. Energy loss depends on the thermodynamic parameters of the natural gas stream on inlet and outlet gas pressure regulation and metering stations. Recovered energy can be used for electricity generation when the pressure regulator is replaced with an expander to drive electric energy generation. To ensure the correct operation of the system, the natural gas stream should be heated, on inlet to expander. This temperature should be higher than the gas stream during choking in the pressure regulator. The purpose of this research was to investigate GRS operational parameters which influence the efficiency of the gas expansion process and to determine selection criteria for a cost-effective application of turboexpanders at selected GRS, instead of pressure regulators. The main novelty presented in this paper shows investigation on discounted payback period (DPP) equation which depends on the annual average natural gas flow rate through the analyzed GRS, average annual level of gas expansion, average annual natural gas purchase price, average annual produced electrical energy sale price and CAPEX.

Orbitofrontal foreign-body injuries comprise a major cause of all facial injuries referred to a neurosurgeon. The authors hereby present an unusual case of a pressure regulator of a domestic pressure cooker impacted into the orbit and extending through the orbital roof into the basifrontal cortex. The globe was intact externally with no obvious sign of such a large object impacted behind the globe. On imaging, the foreign body was found to have fractured the orbital roof with one end protruding into the basifrontal cortex. A transcranial approach was taken to remove the object with removal of the orbital rim and roof to reach the object. After successful retrieval of the metallic body, all displaced bone fragments were removed and the dural closure was done in a watertight manner. The vision could not be salvaged, most likely due to damage to the optic nerve. However, the globe was left intact and the ocular movements were normal. An important factor to consider in removal of such foreign bodies is that the bone fragments that get impacted should be meticulously removed and the dural tears should be sealed to prevent any intracranial infections and cerebrospinal fluid leaks. Removal of the orbital rim helps in adequate exposure of the retro-orbital space and the basifrontal dura. [ABSTRACT FROM AUTHOR]

The pressure regulator is a critically important element in a pneumatic system. It reduces the pressure of a high-pressure air source to the required level for a given pneumatic load and maintains it at a steady level. However, the pressure reduction between the inlet and outlet of a pressure regulator results in a significant power loss, especially when the pneumatic load requires only a low pressure but a large flowrate. In this paper, a design for a new pressure regulator that is capable of reducing this power loss is proposed. Compared to a traditional regulator, the new regulator design adds a component (a vacuum ejector) to draw in additional gas, resulting in an entrainment ratio. This entrainment ratio can reduce the flowrate through the inlet of a regulator. Thus, the power loss incurred by our new regulator is much smaller than that of a traditional design. This paper describes the design and operating principle of the new regulator in detail and evaluates its performance in terms of suction flow, energy-saving, and pressure-stabilization, etc. [ABSTRACT FROM AUTHOR]

A regulator is designed and analyzed in the current paper for medical use in oxygen production centers. The conceptual design procedure starts with a research in the main elements, the operating principles of a pressure regulator and the existed technologies. The sizing guidelines and the important calculations that have to be made are also discussed. The regulator is designed and simulations take place in order optimize the design of the regulator. Stress analysis results are presented for the main body of the regulator, as well as, flow analysis to determine some important flow characteristics in the inlet and outlet of the regulator. Experimental validation takes place in order to monitor the specifications of the regulator in real time working conditions and compare them with the simulation results. [ABSTRACT FROM AUTHOR]

Natural gas in Poland is transported by onshore pipelines with a maximum operating pressure of up to 8.4 MPa. The gas pressure is then reduced to 1.6 MPa or 0.4 MPa for delivery to regional/local distribution networks or to end-user installations. The pressure reduction is usually performed by a pressure regulator. Pressure reduction can also be achieved through expansion of the gas at the turboexpander, which can be harnessed to produce electricity from the recovered mechanical energy of the gas. The main objective of this study is to investigate the factors influencing the efficiency of the gas expansion process and to carry out a feasibility study involving the application of turboexpanders at selected natural gas pressure regulator stations belonging to the Polish transmission system operator Gaz System S.A. [ABSTRACT FROM AUTHOR]

Oxygen production centers produce oxygen in high pressure that needs to be defused. A regulator is designed and analyzed in the current paper for medical use in oxygen production centers. This study aims to design a new oxygen pressure regulator and perform an analysis using Finite Element Modeling in order to evaluate its working principle. In the design procedure,the main elements and the operating principles of a pressure regulator are taking into account. The regulator is designed and simulations take place in order to assessthe proposed design. Stress analysis results are presented for the main body of the regulator, as well as, flow analysis to determine some important flow characteristics in the inlet and outlet of the regulator. [ABSTRACT FROM AUTHOR]

A 50-litre standard hydrogen gas cylinder was temporarily placed in a laboratory to supply hydrogen gas to a flame ionization detector (FID) for use in gas chromatography (GC). On 20 January 2015, the safety relief valve on the pressure regulator failed and released about 0.34 kg of hydrogen into the laboratory. The gas cloud did not ignite so there was no injury or damage. The results of a full investigation with a complete course of action and reconstruction are presented that verify the cause of the leakage and estimate the gas concentration of the dispersion and gas cloud. A preliminary simulation of the likely explosion is provided. If the gas cloud had ignited, the explosion would most likely have caused significant structural damage to doors, windows, and possibly the walls. [ABSTRACT FROM AUTHOR]

Automatic and programmable pressure controllers are critical to miniature pneumatic systems employing pressurized air to transport and manipulate fluidic samples. We have successfully demonstrated (1) a digital pressure control scheme containing active converters and passive regulators that can be readily miniaturized and automated, (2) a 3D PDMS fabrication and integration scheme that can realize on-chip and self-contained pressure controllers for miniature pneumatic systems, and (3) pressure controllers that can switch downstream air pressure between specific levels on demand. In the proposed pressure controller, a regulator is utilized to yield a steady air output, whose pressure is determined by a serial digital-to-analog converter and switched between specific levels on demand. More specifically, a converter guided diaphragm bypasses a certain portion of the input air to reduce and stabilize the output pressure. In the prototype demonstration, PDMS structures were duplicated using 3D-printed molds, bonded and integrated on chip or into self-contained pressure controllers of 25 cm3 in volume. Four-digit converters were employed to realize pressure output at 16 evenly spaced levels. The errors of the measured output pressure were less than 2.4 % of the target pressure while the fluctuations were below 1.2 %. It was also demonstrated that the switching time between pressure levels was less than 0.3 s when digital valves operating at 10 Hz were utilized. As such, the demonstrated miniature pressure controllers could replace their bulky/costly counterparts, and automatic and programmable control of pneumatically driven systems could potentially be realized. [Display omitted] [ABSTRACT FROM AUTHOR]

This article is devoted to the development of a combined method for working processes calculation in pneudraulic devices. The method is based on execution of interrelation between the mathematical models of the work processes in approximation of lumped and distributed medium thermodynamic state parameters and makes it possible to take into account irregularity of the pressure distribution inside a vessel. In the article this method is implemented on the basis of the low-end gas pressure regulator and the basic results of the computation and their concise analysis are presented. [ABSTRACT FROM AUTHOR]

Direct acting pressure regulator is widely used for ensuring high uniformity and security for irrigation system. This research is aimed to investigate the effect of geometric and spring parameters of the pressure regulator on its regulating performance. For this purpose, an improved numerical simulation method was presented to obtain the entire characteristic curves including both the performance line of unregulated segment and performance curve of regulated segment. The modification of partial boundary conditions and calculating process of the dynamic model which was established in a previous study were carried out. The flow rate of pressure regulator calculation domain was controlled by a further downstream orifice along with the appropriate pipe length before and after the orifice, instead of directly setting the flow rate on the regulator outlet boundary. The cross section area of the orifice increased or decreased by its boundary moving till the desired flow rate obtained. The technique of layering dynamic mesh was employed for the movement of the orifice and the regulating plunger boundaries and mesh deformation of surrounding flow domain. The velocity of the orifice boundary, the calculation process of dynamic equilibrium of the regulating plunger, and the spring stiffness were carried out using a special user defined functions developed to couple with ANSYS Fluent code in every time step. Results of numerical simulations under inlet pressure ranging from 0.025 to 0.4 MPa and different flow rate conditions were verified by laboratory measurements. The influence of the geometric and spring parameters of the pressure regulator on its preset pressure and initial regulating pressure was investigated using the validated numerical simulation method by single-factor and five-level experiment design. The results shown that the relative deviation between numerical preset pressure and slope of performance line of unregulated segment and test values lay within-19.3 and 9.4 %, respectively. Numerically predicted performance indexes were in reasonable agreement with those obtained by experimental tests, which verified the reliability and calculation accuracy of the proposed numerical simulation method. The preset pressure dropped nonlinearly as the increase of two parameters affecting the force induced by water pressure difference of the regulating plunger which were the sectional areas of plunger upstream face and downstream face. The preset pressure rose proportionally with the increase of three parameters affecting the spring force that were the height of the flow orifice of the seat, the spring stiffness, and the pre-stressed spring length. The initial regulating pressure reduced with increase in the sectional area of plunger upstream face, the height of the flow orifice of the seat, the spring stiffness, and pre-stressed spring length respectively, whereas with a decrease in the sectional area of plunger downstream face. Effects of geometrical and spring parameters on regulating performance are successfully revealed thought the computational fluid dynamics analysis which forms the theoretical basis for future design and optimization of pressure regulator. [ABSTRACT FROM AUTHOR]

Alternative fuels such as compressed natural gas (CNG) have lately gained an increasing interest due to the even more stringent emission regulations and environmental policies. Considerable R&D activity has been carried out in order to enhance the mixture formation and to improve the after treatment efficiency. The achievement of these goals cannot disregard the importance of the injection system and of its component (common rail, injectors and pressure reducing valve) on the air-to-fuel mixing. The amount of injected fuel should in fact be properly targeted by the ECU basing on the estimation of the induced air and accounting for the embedded closed-loop strategies. Still, these latter are normally derived from engine-base routines and totally ignore the injection system dynamics. The present paper aims at developing a thorough model of the injection system with specific attention to the one component which significantly contributes to fully defining its dynamic response, i.e. the pressure reducing valve. The pressure reducer is made up of various elements that retain diverse weights on the valve behavior and should consequently be differently addressed to. The research has been focused on defining the set of parameters to be precisely reproduced in the 0D-1D simulation so as to match the injection system experimental behavior. A refined model of the pressure reducer has hence been proposed and the model has been calibrated, tested and run under various operating conditions so as to assess for the set-up validity. Comparisons have been carried out on steady state points as well as through out a vehicle driving cycle and the model capability to properly reproduce the real system characteristic has been investigated into. The proposed valve model has proved to consistently replicate the injection system response for different speed and load conditions. A few methodological indications concerning modeling aspects of a pressure regulator can be drawn from the present study. Finally, the model has been run in a predictive mode so as to inquiry into the response of the system to fast transient operations, both in terms of speed and load. The model outputs have highlighted mismatches between the ECU target mass and the actually injected one and have hinted at the need for dedicated and refined control strategies capable of preventing anomalies in the mixture formation and hence in the engine functioning. [ABSTRACT FROM AUTHOR]

The main tasks and challenges for pressure regulation in the drum-separators of RBMK-1000 reactors are described. New approaches to constructing algorithms for pressure control in drum-separators by electro-hydraulic turbine control systems are discussed. Results are provided from tests of the operation of modernized pressure regulators during fast transients with reductions in reactor power. [ABSTRACT FROM AUTHOR]

This paper proposed a modified three-stage auto-cascade refrigeration cycle (MTARC) associated with an intermediate pressure regulator. The energy and exergy analyses indicate that the MTARC can acquire lower evaporating temperature, greater cooling capacity and higher COP. Under a typical operating condition, the MTARC using the alternative ternary zeotropic mixture of R1234yf/R41/R14(0.66/0.17/0.17) has an evaporator inlet temperature of −90.90 °C, COP of 0.4509 and exergy efficiency of 40.67%, which are 4.63 °C lower, 32.93% and 15.38% higher than those of the conventional three-stage ARC, respectively. Further research shows that with the decreasing intermediate pressure, the thermodynamic performance of the MARC can be improved significantly, but the compressor exhaust temperature also increases. When the intermediate pressure decreases from 1.8 MPa to 1 MPa, the cooling capacity, COP and exergy efficiency of the MTARC increase by 30.34%, 22.10% and 13.79% respectively, while the exhaust temperature increases 18.59 °C from 116.66 °C to 135.25 °C, which indicates that the selection of intermediate pressure needs to be comprehensively considered. The proposed new approach is valuable for optimizing the design and application of the refrigerator at an ultra-low temperature level of −80 °C. • A modified three-stage auto-cascade refrigeration cycle with a pressure regulator is proposed. • The alternative ternary zeotropic mixture of R1234yf/R41/R14 is adopted. • The modified cycle has a 32.93% improvement in COP. • The improvement in the exergy efficiency is mainly contributed by the compressor. [ABSTRACT FROM AUTHOR]

Water consumption at different time of the day is uneven. The model of steady flow distribution in water-supply networks is calculated for maximum consumption and effectively used in the network design and reconstruction. Quasi-stationary modes, in which the parameters are random variables and vary relative to their mean values are more suitable for operational management and planning of rational network operation modes. Leaks, which sometimes exceed 50% of the volume of water supplied, are one of the problems in water-supply systems. One of the ways to reduce leaks is zoning (overpressure zone definition) and pressure regulators installation. The method of reengineering water networks by their zoning and pressure regulators installation was developed in the paper. Its implementation provides a significant reduction of the total overpressure in the water network nodes, water leak volumes and saving material and energy resources. The improved method for zoning the water network is based on the stochastic model of quasi-stationary modes in the water supply and distribution systems, and pressure regulators parameters optimization for each determined zone. [ABSTRACT FROM AUTHOR]

This study investigates characteristics of transient flow and the possibility of freezing in a pressure regulator and the rear connecting pipe of the pressure regulator during the closing process of the pressure control valve (PCV), which is an essential element in the operation of a natural gas pipeline network. For this purpose, the study develops a numerical model for the PCV and its rear connecting pipe by applying computational fluid dynamics method. The analysis is conducted in each of two cases: (1) a steady-state analysis in the case of normal operation and (2) an unsteady-state analysis in the case of emergency closure in problematic situations. First, we closely examine characteristics of internal flow in the pressure regulator and the rear connecting pipe when the PCV operates regularly with a 50% opening ratio in a steady state. Afterwards, unsteady-state analysis examines characteristics of transient flow, such as lowered pressure and temperature, velocity change, etc., of rear flow in the pressure regulator when the PCV is closed because of trouble in the pressure control system. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes a scheme for electronically regulating the flow of propellant to the thruster from a high-pressure storage tank used in spacecraft application. Precise flow delivery of propellant to thrusters ensures propulsion system operation at best efficiency by maximizing the propellant and power utilization for the mission. The proposed field programmable gate array (FPGA) based electronic flow regulator (EFR) is used to ensure precise flow of propellant to the thrusters from a high-pressure storage tank used in spacecraft application. This paper presents hardware and software design of electronic flow regulator and implementation of the regulation logic onto an FPGA. Motivation for proposed FPGA-based electronic flow regulation is on the disadvantages of conventional approach of using analog circuits. Digital flow regulation overcomes the analog equivalent as digital circuits are highly flexible, are not much affected due to noise, accurate performance is repeatable, interface is easier to computers, storing facilities are possible and finally failure rate of digital circuits is less. FPGA has certain advantages over ASIC and microprocessor/micro-controller that motivated us to opt for FPGA-based electronic flow regulator. Also the control algorithm being software, it is well modifiable without changing the hardware. This scheme is simple enough to adopt for a wide range of applications, where the flow is to be regulated for efficient operation. The proposed scheme is based on a space-qualified re-configurable field programmable gate arrays (FPGA) and hybrid micro circuit (HMC). A graphical user interface (GUI) based application software is also developed for debugging, monitoring and controlling the electronic flow regulator from PC COM port. [ABSTRACT FROM AUTHOR]

Pressure-driven flow control systems are a critical component in many microfluidic devices. Compartmentalization of this functionality into a stand-alone module possessing a simple interface would allow reduction of the number of pneumatic interconnects required for fluidic control. Ideally, such a module would also be sufficiently compact for implementation in portable platforms. In our current work, we show the feasibility of using a modular array of Venturi pressure microregulators for coordinated droplet manipulation. The arrayed microregulators share a single pressure input and are capable of outputting electronically controlled pressures that can be independently set between ±1.3 kPa. Because the Venturi microregulator operates by thermal perturbation of a choked gas flow, this output range corresponds to a temperature variation between 20 and 95°C. Using the array, we demonstrate loading, splitting, merging, and independent movement of multiple droplets in a valveless microchannel network. [ABSTRACT FROM AUTHOR]

Abstract: Pressure regulators are important elements in pneumatic systems. Relief-type precision pressure regulators are commonly used to control the supply pressure to actively controlled pneumatic vibration isolators. Herein, a high precision, quick response pneumatic pressure regulator is proposed. This consists of an isothermal chamber, a servo valve, a pressure sensor, a quick response laminar flow sensor (QFS), and a pressure differential sensor (PD sensor) as developed by the authors. Slight changes of pressure in the chamber can be detected by the PD sensor and are fed back to the servo valve to maintain the pressure at a desired value. The performance of this regulator was confirmed experimentally in comparison with one available commercially. The regulator was then applied to the supply pressure regulation of an actively controlled pneumatic vibration isolation table. The superior performance of the regulator is clearly shown in the experimental results, especially in terms of avoiding effects from upstream or downstream disturbances. [Copyright &y& Elsevier]

The dynamics of an indirect pressure regulator in which the primary valve is a toroidal elastic element is considered. A mathematical model of its transfer function is derived. [ABSTRACT FROM AUTHOR]

Long-distance gas transfer requires high pressure, which has to be reduced before the gas is conveyed to the customers. This pressure reduction takes place at natural gas pressure reduction stations, where gas pressure is decreased by using gas flow energy for overcoming local resistance, represented by a throttling valve. This pressure energy can be reused, but it is difficult to implement it at small pressure reduction stations, as the values of unsteadiness significantly increase when the gas approaches consumers, whereas gas flow rate and pressure decrease. This work suggests replacing throttling valves at small pressure reduction stations for expander-generator units, based on volumetric expanders. Two implementations are proposed. A mathematical model of gas-dynamic processes, which take place in expander-generator units, was developed using math equations. With its help, a comparison was made of the stability of the operation of two possible control schemes in non-stationary conditions, and the feasibility of using an expander-generator regulator as a primary one for a small natural gas pressure reduction station was confirmed. [ABSTRACT FROM AUTHOR]

Abstract: Gas pressure regulators are widely used in both commercial and residential applications to control the operational pressure of the gas. One common problem in these systems is the tendency for the regulating apparatus to vibrate in an unstable manner during operation. These vibrations tend to cause an auditory hum in the unit, which may cause fatigue damage and failure if left unchecked. This work investigates the stability characteristics of a specific type of hardware and shows the cause of the vibration and possible design modifications that eliminate the unstable vibration modes. A dynamic model of a typical pressure regulator is developed, and a linearized model is then used to investigate the sensitivity of the most important governing parameters. The values of the design parameters are optimized using root locus techniques, and the design trade-offs are discussed. [Copyright &y& Elsevier]