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In response to improve the quality and level of hydrostatic transmission (HST) products for modern mobile machineries, the closed-loop transfer functions of a HST are established by mathematical modeling, a comprehensive testing equipment is developed employing a proportional relief valve for automatic program loading and fuzzy-PID oil temperature control, the testing equipment is capable of conducting various performance tests for various models of HST integrated pump-motor products, including factory and type tests, especially continuous impact and endurance performance tests under high temperature and high-speed conditions. Comprehensive performance test of the above test sample is carried out using the developed equipment, that the test results agree well with the previous simulation results verifies the correctness of the established theoretical analysis model. The obtained theory and equipment from this work provide theoretical and experimental technical support for improving design and development of high-end fluid components for modern mobile machinery HST. [ABSTRACT FROM AUTHOR]

• A path integration method is proposed for Markovian jump stochastic systems. • The augmented system and its stochastic source are created. • A probability mapping about the stochastic source and system evolution is derived. • The transition probability density function of the augmented system is obtained. • The stochastic hydraulic relief valve model with Markovian jumps is developed. A path integration method for solving Markovian jump stochastic dynamical systems is presented. The Markovian jump process and the state vector of the system are combined into a new augmented state vector. The randomness of the Markovian jump is modeled by a stochastic process, which is merged with the stochastic perturbations to form the stochastic source affecting the evolution of the augmented system. Then a probability mapping is constructed, mapping the probability space of the stochastic source to the short-time transition probability density function of the augmented system. By solving this probability mapping, the short-time transition probability density function of the path integration method is obtained, thus a path integration method is customized for Markovian jump stochastic systems. Finally, a hydraulic relief valve system is used as an application example to demonstrate the availability of the path integration algorithm. The results suggest that the pre-compression parameters and coefficient of restitution of the plug can induce stochastic P-bifurcation phenomena. When the above two parameters are small, the system becomes unstable with the parameters taken in this example. Monte Carlo simulations prove that the proposed method effectively captures the transient and stationary responses of Markovian jump systems. [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.)

A faulty voltage measurement can lead to the overcharging of a Li-Ion cell, resulting in gas formation and heating inside the cell, which can trigger thermal runaway. To mitigate this risk, cylindrical cells are equipped with a Current Interrupt Device (CID), which functions as a pressure relief valve, disconnecting the electrical circuit within the cell when internal pressure rises. However, this disconnection causes the cell to suddenly become highly resistant, posing a significant issue in series-connected cells. In such configurations, a portion or even the entire system voltage may drop across the disconnected cell, substantially increasing the likelihood of an electric arc. This arc could ignite any escaping flammable gases, leading to catastrophic failures. In a series of tests conducted on three different cell chemistries—NMC (Nickel Manganese Cobalt), NCA (Nickel Cobalt Aluminum), and LFP (Lithium Iron Phosphate)—it was found that the safe operation of the CID cannot be guaranteed for system voltages exceeding 120 V. Although comparative tests at double the nominal cell voltage did not exhibit the same behavior, these findings suggest that current safety standards, which recommend testing at double the nominal voltage, may not adequately address the risks involved. The tests further revealed that series connections of cells with CIDs are inherently dangerous, as, in the worst-case scenario, the entire system voltage can be concentrated across a single cell, leading to potential system failure. [ABSTRACT FROM AUTHOR]

High voltage circuit breakers are important equipment in power systems, and the valve motion of the chambers plays a role in the arc extinguishing performance of high-voltage circuit breakers. Therefore, in this paper, a 145 kV auto-expansion SF6 circuit breaker is taken as the research object, and a two-dimensional axisymmetric magnetohydrodynamic arc model considering valve motion process is established. The influence of different short circuit breaking conditions on the valve motion was studied. The results show that the backflow phenomenon of ablated steam is the main reason for the closure of the non-return valve, which plays an important role in opening the pressure relief valve. The closing time of the non-return valve is about 0.4 ms faster at a short circuit current of 40 kA than at a short circuit current of 36 kA. [ABSTRACT FROM AUTHOR]

This work provides novel insights into the uncertainty quantification and reliability sensitivity analysis of a direct-operated relief valve undergoing vibration. A reliability model for pressure tolerance failure of the relief valve is developed based on the criterion that the pressure tolerance exceeded the allowable value, incorporating the vibration and multiparameter uncertainty. The Simulink simulation is employed to analyze the nonlinear behaviors of the valve. To avoid excessive nonlinear calculations, a Kriging-based strategy is adopted for reliability sensitivity analysis, allowing for rapid estimation of nonlinear responses. The results are compared with those obtained by MCS to verify the performance of the proposed method. The sensitivity results indicate that the proposed method saves 98 % of computational time without much loss of accuracy. Furthermore, more attention should be paid to the spring stiffness, valve element mass, and controlled chamber volume in the structural reliability design of relief valves. [ABSTRACT FROM AUTHOR]

The Bhopal Gas Tragedy, considered the worst industrial disaster in history, occurred in 1984 at a chemical plant in Bhopal, India. Water entered a storage tank containing methyl isocyanate (MIC), causing a release of toxic gas that resulted in numerous deaths and injuries. The incident led to the establishment of the Center for Chemical Process Safety (CCPS) to promote process safety management. The article emphasizes the importance of process safety culture in preventing chemical accidents and discusses the hazards of MIC and the need for refrigeration systems. It also highlights the failure of the high-temperature alarm system and the importance of addressing equipment reliability and process safety culture. The article concludes by suggesting that organizations prioritize equipment performance and avoid accepting equipment failures. [Extracted from the article]

Copyright of Journal of South China University of Technology (Natural Science Edition) is the property of South China University of Technology 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.)

Thermal runaway characteristics and hazards of lithium-ion batteries under low ambient pressure in-flight conditions are studied in a dynamic pressure chamber. The influence of ambient pressures (95 kPa and 20 kPa) and packaging forms (cylindrical and pouch commercial batteries) were especially investigated. The results show that the values of heat release, temperature, and C O 2 concentration decrease with the reduction in pressure from 95 kPa to 20 kPa, while the total hydrocarbon and C O   increase. Without violent fire, explosion, and huge jet flames, the thermal hazards of TR fire under 20 kPa are lower, but the amount of toxic/flammable gas emissions increases greatly. The amount of C O and hydrocarbons varies inversely with the thermal hazards of fire. Under low-pressure environments of cruise altitude, the thermal hazards of TR fire for pouch cells and the toxic/potentially explosive hazards of gas emissions of cylindrical cells need more attention. The performance of TR hazards for two packaging types of battery is also different. Pouch cells have higher thermal hazards of fire and lower combustible/toxic emitted gases than cylindrical cells. The thermal runaway intensity of individual cells decreases under lower ambient pressure, but the burning intensity increases dramatically when thermal runaway occurs in a battery pack. The open time of a safety valve (rupture of the bag) is shortened, but the trigger time for a thermal runaway varies for different formats of batteries under 20 kPa. Those results may be helpful for the safety warning and hazard protection design of Li batteries under low-pressure conditions. [ABSTRACT FROM AUTHOR]

Julia Prest's book, "Public Theatre and the Enslaved People of Colonial Saint-Domingue," provides a comprehensive examination of the history of theater in eighteenth-century Saint-Domingue. By analyzing local newspaper theater announcements, Prest uncovers the involvement of enslaved people, particularly urban domestics, in theater production. The book delves into the complexities of race and power dynamics within performances, highlighting the limits of speculation and the ethical responsibilities of historians. Additionally, the text explores the concept of mitigation and challenges assumptions about the homogeneity of the theater audience, while also examining the role of disability in the archives and its connection to violence and oppression. The author suggests that the public theater may have served as a means to alleviate societal tensions and reinforce hierarchies of ability. [Extracted from the article]

This article focuses on the safety valve of pressure vessels, and a new ferrofluid sealing device for pressure vessel safety valves is developed based on a special magnetic circuit. A combined method of numerical calculation and experimental analysis is used to study the relationship between seal clearance, number of seals, pole slot width, pole tooth height, pole tooth width, and the sealing pressure of the ferrofluid sealing device. The research results show that seal clearance and pole tooth width have a significant impact on the sealing performance, and as the dimensions increase, the sealing pressure decreases. As the number of seals, pole tooth height, and slot width increase, the sealing performance initially improves and then decreases. This phenomenon is attributed to the increase in magnetic reluctance in the magnetic circuit. In experimental studies, when the excitation current of the electromagnet is 240 mA and the coil turns number 30, the sealing capacity is 61.22 kPa. When the excitation current is 200 mA and the coil turns number 80, the sealing capacity is 168.24 kPa. The experiments demonstrate the compensating ability of magnetic fluid seals in combination with safety valve seals, confirming that combined seals have higher reliability compared to conventional mechanical seals. [ABSTRACT FROM AUTHOR]

Programmable variable pressure valves were introduced in the 1980s, providing a non-invasive solution to post-operative alterations of the valve opening pressure to address problems of under or overdrainage. Since their increased use in the treatment of hydrocephalus, there have been case reports of unintentional alterations of the valve opening pressure following exposure to magnetic fields in everyday environments, from televisions to rollercoasters. Here we describe two cases of patients' programmable valves being altered following audiology assessments. We subsequently discuss some of the available research on the safety of these valves in various magnetic field strengths, alongside interim and updated recommendations made by the British Society of Audiologists with regards to testing of children with programmable shunts in place. [ABSTRACT FROM AUTHOR]

This paper critically reviews various energy-saving models used for enhancing the energy efficiency of hydrostatic power transmission drives. The system layout, component design, and controllers used are discussed in detail in its sub-category. Based on the detailed review of various energy-saving models, a novel energy-efficient hydrostatic power transmission drive of the chairlift transport system (CTS) is proposed. The rise in fluid temperature in the existing hydraulic arrangement of the CTS, owing to its continuous recirculation, is controlled by incorporating the flushing valve, while the boost pump replenishes the fluid volume loss. However, because of its loading nature, the CTS's existing power transmission drive encounters energy losses and uncontrolled fluid cooling. In the present study, the hydraulic circuit design of the existing power transmission drive of the CTS is modified to reduce energy losses. Using a variable displacement auxiliary pump in the system helps minimize the energy losses through the pressure relief valve. Also, the proposed design enhances the cooling efficiency of the flushing valve unit controlled through a suitably designed Fuzzy logic controller having a dependency on fluid temperature. The simulation model is made in MATLAB/ Simulink® environment, and the result shows that, with the increase in speed, the orifice area opening of the proportional flow control valve increases to prevent oil temperature from exceeding the operating range and the same decreases for a reduced speed. Furthermore, the proposed system exhibits a significant energy saving of 32 kJ over 300 s, demonstrating its improved efficiency compared to the existing system. [ABSTRACT FROM AUTHOR]

[Objective] To reduce the adverse effects of water hammer on the buildings in long-distance high-lift water conveyance projects, and to ensure the safety of pipelines buildings. [Method] Based on the transient flow theory and the characteristic line method combined with the mathematical model of water column separation, and considering the boundary conditions of water hammer protection equipment, the hydraulic simulation software was used to calculate the water hammer hydraulic. The traditional "one-way surge tank + air valve" and "water hammer relief valve + axial flow check valve + air valve" two water hammer protection measures were numerically calculated and compared to verify the protection effect of the water hammer protection system combined with the axial flow check valve and the water hammer relief valve. [Result] After calculation and verification of many years of operation in the later actual project, it was shown that in the long-distance high-lift water conveyance project, the two water hammer protection schemes have certain protective effects on the high-pressure and negative-pressure water hammer of the pipeline under the accident pump shutdown. The protective measures of "one-way surge tank + air valve" can reduce the negative pressure in the pipeline from the vaporized negative pressure -8.4 m to the head pressure of -6.9 m, and the maximum positive pressure of the pipeline is reduced from 4.25 Mpa to 2.98 Mpa. However, if we want to continue to reduce the negative pressure of the pipeline, we need to increase the number of surge tanks and increase the project investment, and there is no economic advantage. The water hammer protection measures of "water hammer relief valve + axial flow check valve + air valve" can effectively protect the high and low pressure water hammer and pump backflow caused by pump stoppage. The negative pressure in the pipeline is reduced from the vaporized negative pressure to the -5 m head pressure, so that the maximum pressure in the system is reduced from 4.25 Mpa to 3.0 Mpa, and the maximum pressure in the pipeline is controlled within 1.2 times of the steady-state pressure. [Conclusion] Years of operation after the completion of the project has verified that the water hammer protection system only needs to set up a water hammer relief valve and an axial flow check valve in the water conveyance system to achieve effective protection against high and low pressure water hammer caused by pump shutdown and pump backflow and other issues. It has the same reliability and higher economy, and can provide a basis for the design of water hammer in similar projects. [ABSTRACT FROM AUTHOR]

Ternary lithium batteries have been widely used in transportation and energy storage due to their high energy density and long cycle life. However, safety issues arising from thermal runaway (TR) need urgent resolution. Current research on thermal runaway in large-capacity ternary lithium batteries is limited, making the study of hazard indicators during the thermal runaway ejection process crucial. This study places a commercial 156 Ah prismatic battery (positive electrode material: Li(Ni0.8Mn0.1Co0.1)O2, negative electrode material: graphite) in a nitrogen-filled sealed container, triggering thermal runaway through lateral heating. The experimental results show that the battery's maximum surface temperature can reach 851.8–943.7 °C, exceeding the melting point of aluminum. Temperature surge inflection points at the battery's bottom and near the small side of the negative electrode coincide with the inflection point on the heated surface. The highest jet temperatures at three monitoring points 50 mm, 150 mm, and 250 mm above the safety valve are 356.9 °C, 302.7 °C, and 216.5 °C, respectively. Acoustic signals reveal two ejection events. The average gas production of the battery is 0.089 mol/Ah, and the jet undergoes three stages: ultra-fast ejection (2 s), rapid ejection (32 s), and slow ejection (47 s). Post-thermal runaway remnants indicate that grooves from internal jet impacts are mainly located at ±45° positions. This study provides valuable insights for the safety design of batteries and the suppression of thermal runaway propagation. [ABSTRACT FROM AUTHOR]

With the widespread application of lithium-ion batteries (LIBs) energy storage stations in high-altitude areas, the impact of ambient pressure on battery thermal runaway (TR) behavior and venting flow characteristics have aroused wide research attention. This paper conducts a lateral heating experiment on 280 Ah lithium iron phosphate batteries (LFPs) and proposes a method for testing battery internal pressure using an embedded pressure sensor. This paper analyzes the battery characteristic temperature, internal pressure, chamber pressure, and gas components under different chamber pressures. The experiment is carried out in a N2 atmosphere using a 1000 L insulated chamber. At 40 kPa, the battery experiences two instances of venting, with a corresponding peak in temperature on the battery's side of 136.3 °C and 302.8 °C, and gas generation rates of 0.14 mol/s and 0.09 mol/s, respectively. The research results indicate that changes in chamber pressure significantly affect the center temperature of the battery side (Ts), the center temperature of the chamber (Tc), the opening time of the safety valve (topen), the triggering time of TR (tTR), the time difference (Δt), venting velocity, gas composition, and flammable limits. However, the internal pressure and gas content of the battery are apparently unaffected. Considering the TR characteristics mentioned above, a safety assessment method is proposed to evaluate the TR behavior and gas hazard of the battery. The results indicate that the risk at 40 kPa is much higher than the other three chamber pressures. This study provides theoretical references for the safe use and early warning of energy storage LIBs in high-altitude areas. [ABSTRACT FROM AUTHOR]

Innate immune cells play a key role in inflammation as a source of proinflammatory cytokines. However, it remains unclear how innate immunitymediated inflammation is fine-tuned to minimize tissue damage and assure the host's survival at the early phase of systemic inflammation. The results of this study with mouse models demonstrate that the supply of monocytes is restricted depending on the magnitude of inflammation. During the acute phase of severe inflammation, monocytes, but not neutrophils, were substantially reduced by apoptosis and the remaining monocytes were dysfunctional in the bone marrow. Monocyte-specific ablation of Casp3/7 prevented monocyte apoptosis but promoted monocyte necrosis in the bone marrow, leading to elevated levels of pro-inflammatory cytokines and the increased mortality of mice during systemic inflammation. Importantly, the limitation of monocyte supply was dependent on pro-inflammatory cytokines in vivo. Consistently, a reduction of monocytes was observed in the peripheral blood during cytokine-release syndrome (CRS) patients, a pathogen-unrelated systemic inflammation induced by chimeric antigen receptor-T cell (CAR-T cell) therapy. Thus, monocytes act as a safety valve to alleviate tissue damage caused by inflammation and ensure host survival, which may be responsible for a primitive immune-control mechanism that does not require intervention by acquired immunity. [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.)

This paper presents an experimental investigation into shockwave and flame characteristics of compressed hydrogen released through various types of pressure relief devices (PRDs) for which data have not been previously reported. Burst disks and safety valves with different set pressure (P0) of 22–140 MPa were tested. Shockwave intensity/velocity spontaneous ignition/flame behavior was monitored by in-situ pressure/light sensors, respectively. Previous works have mostly focused on burst disks with low P0 (under 10 MPa), leaving safety valves and high-pressure burst disks uninvestigated. It was found that shockwave/spontaneous ignition behavior differs with PRD types. Spontaneous ignition occurs in all burst disk cases, along with an ignition/self-extinguishment/reignition process with relatively low P0, which has not been revealed previously. In contrast, none of the safety valves cause spontaneous ignition, resulting from the absence of shockwave due to lower overpressure values/rise rate during release. This suggests that shockwave formed by sudden release is the most dominant factor in spontaneous ignition. Also, the occurrence of self-extinguishment does not guarantee the absence of jet flame. This work provides a comprehensive database revealing shockwave and flame characteristics of hydrogen released through different PRDs, which offers basic data and theoretical support for the safety and risk assessment of high-pressure hydrogen facilities. [ABSTRACT FROM AUTHOR]

As China's power grows, a widespread perception is that China is more willing to respond to nationalist demands and act assertively in international incidents. In reality, China has not supported and accommodated nationalism in all events but has cooled down nationalism in some cases. An important unanswered question is, why does the Chinese government demonstrate selectivity when responding to nationalism and take different foreign policies concerning nationalism in various incidents? This article provides a coherent and testable framework to answer this question and uses five cases to test the congruence and validity of the analytical framework. The core argument is that the primary concern of the Chinese government in dealing with nationalism is its legitimacy. When policymakers perceive severe threats to China's regime security and stability, they will open a 'safety valve' to embrace nationalism, allowing nationalism to unleash its anger under the government's monitor and escalating disputes to defend national interests and appease nationalism. When there are few threats to the regime, three factors will affect China's choice: the economic value of the diplomatic relationship, elements of China's core interests, and the viability of reaching an agreement that sets aside the dispute. [ABSTRACT FROM AUTHOR]

Copyright of Humanities & Educational Sciences Journal is the property of Humanities & Educational Sciences Journal 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.)

Direct-acting relief valves are important pressure-control components in hydraulic systems; however, noise problems are now common. This study aimed to reduce and numerically analyze the valve cavitation and noise using the Zwart–Gerber–Belamri (ZBG) model with the Ffowcs Williams and Hawkings (FW–H) model to optimize the design based on the sound field perspective. First, a direct-acting relief valve flow field model was established to determine the relationship between the seat structure and the degree of cavitation through a CFD (Computational Fluid Dynamics) simulation. Second, sound field analysis was conducted based on the cavitation and non-cavitation flow fields, respectively, and the resulting noise levels were compared. Finally, prototypes of the relief valve were manufactured, and noise levels between the original and optimized valves were compared. The results revealed that cavitation within the relief valve generated noise while optimizing the valve seat cone angle suppressed this phenomenon, thereby reducing the noise emitted by the optimized valve by 18.2 dB compared to the original valve. These findings can serve as a guide for designing and optimizing direct-acting relief valves. [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.)

In Nuclear Power Plants (NPPs), online condition monitoring and the fault detection of structures, systems and components (SSCs) can aid in guaranteeing safe operation. The use of data-driven methods for these tasks is limited by the requirement of physically consistent outcomes, particularly in safety-critical systems. Considering the importance of regulating valves (e.g., safety relief valves and main steam isolation valves), this work proposes a multistage Physics-Informed Neural Network (PINN) for fault detection in such components. Two stages of the PINN are built by developing the process model of the regulating valve, which integrates the basic valve sizing equation into the loss function to jointly train the two stages of the PINN. In the 1st stage, a shallow Neural Network (NN) with only one hidden layer is developed to estimate the equivalent flow coefficient (a key performance indicator of regulating valves) using the displacement of the valve as input. In the 2nd stage, a Deep Neural Network (DNN) is developed to estimate the flow rate expected in normal conditions using inputs such as the estimated flow coefficient from the 1st stage, the differential pressure, and the fluid temperature. Then, the residual, i.e., the difference between the estimated and measured flow rates, is fed into a Deep Support Vector Data Description (DeepSVDD) to detect the occurrence of faults. Moreover, the deviation between the estimated flow coefficients of normal and faulty conditions is used to interpret the consistency of the detection result with physics. The proposed method is, first, applied to a simulation case implemented to emulate the operating characteristics of regulating the valves of NPPs and then validated on a real-world case study based on the DAMADICS benchmark. Compared to state-of-the-art fault detection methods, the obtained results from the proposed method show effective fault detection performance and reasonable flow coefficient estimation, thus guaranteeing the physical consistency of the detection results. [ABSTRACT FROM AUTHOR]

Plants have evolved multiple regulatory mechanisms to cope with natural light fluctuations. The interplay between these mechanisms leads presumably to the resilience of plants in diverse light patterns. We investigated the energy‐dependent nonphotochemical quenching (qE) and cyclic electron transports (CET) in light that oscillated with a 60‐s period with three different amplitudes. The photosystem I (PSI) and photosystem II (PSII) function‐related quantum yields and redox changes of plastocyanin and ferredoxin were measured in Arabidopsis thaliana wild types and mutants with partial defects in qE or CET. The decrease in quantum yield of qE due to the lack of either PsbS‐ or violaxanthin de‐epoxidase was compensated by an increase in the quantum yield of the constitutive nonphotochemical quenching. The mutant lacking NAD(P)H dehydrogenase (NDH)‐like‐dependent CET had a transient significant PSI acceptor side limitation during the light rising phase under high amplitude of light oscillations. The mutant lacking PGR5/PGRL1‐CET restricted electron flows and failed to induce effective photosynthesis control, regardless of oscillation amplitudes. This suggests that PGR5/PGRL1‐CET is important for the regulation of PSI function in various amplitudes of light oscillation, while NDH‐like‐CET acts' as a safety valve under fluctuating light with high amplitude. The results also bespeak interplays among multiple photosynthetic regulatory mechanisms. Summary statement: PGR5/PGRL1‐dependent cyclic electron transports (CET) protect photosystems against light fluctuations of varying amplitudes, while NDH‐like‐dependent CET acts as a safety valve to optimise photosynthesis in high amplitude light fluctuations. Interplays may exist among multiple regulatory mechanisms, including quenching and CET. [ABSTRACT FROM AUTHOR]

Research aimed at hydrogen fuel cells (HFC) has increased recently, driven by the need for viable alternative methods to generate energy for automotive vehicles, aside from fossil fuels. Before implementing hydrogen systems in vehicles, it is necessary to conduct comprehensive tests in a bench setup to ensure maximum efficiency before scaling up the system. Therefore, it is often essential to make modifications to the bench system to improve it. This paper aims to document the use of Management of Change (MOC) reviews to modify a proton-exchange membrane fuel cell (PEMFC) bench system. The previous layout included a hydrogen cylinder and three valves before the PEMFC: a pressure reduction valve, a pressure relief valve, and a shutoff valve. After the HFC, the non-reacted hydrogen and water produced during the reaction were eliminated through a purge valve. In the modified setup, an accumulator was added before the PEMFC, along with a non-reacted hydrogen reuse system that redirects the product exit of the HFC back to the accumulator. This change aimed to enhance the efficiency of electrical current production per mole and improve the process's safety by preventing hydrogen release into the atmosphere. To ensure the process's integrity and safety, MOC reviews were implemented, covering maintenance, operational, technical, and security aspects. This improvement enhances the system used by the team. MOC reviews are an essential engineering tool that increases the success rate of improvements in functioning processes, even minor ones. Additionally, the modifications to the PEMFC feed system have reduced operational costs and increased the bench's viability for use. [ABSTRACT FROM AUTHOR]

The paper is dedicated to the multi-criteria choice of an optimal variant of a pressure relief valve with a nominal pressure of 3 bar, manufactured from four different materials. The paper includes the usage of a number of existing methods that are combined in an appropriate way to solve a specific practical problem, and a sequence of steps for their effective application is formulated. The optimization is defined and analyzed, and a seven-stage solution approach is developed. A list of requirements for the product is composed. The requirements are organized into objective groups, and an objective tree is developed. Metrics for measuring the requirements are defined. The "House of Quality" tool is used for correlating the metrics and requirements. Based on these correlations, criteria are selected for the evaluation of alternative variants. A mathematical model of the problem is built, and the evaluation criteria are defined in terms of concrete values for the variants, transforming the criteria into objective functions. A normalization method for the objective functions is selected and a principle of optimality is chosen. Using a known method for defining objective functions' priorities, the weighting factors for different priority scenarios are obtained. The results of the optimization are shown for the different scenarios in relation to the different priorities (importances) of the selected criteria. Seven optimization problems are solved, and three different solutions are found. The solutions are graphically represented on a radar chart. All solutions found are optimal according to the selected criterion for optimality and calculated weight vectors. The final solution, chosen among the optimal ones found, is selected on the basis of additional decision makers' considerations. [ABSTRACT FROM AUTHOR]

The purpose of this research is to solve the complex long-distance and high-lift water supply engineering accident water hammer protection problem. Taking the Zhaojinzhuang water supply project as an example, based on the method of characteristics (MOC), the water hammer of the pumping station under the combined action of a water hammer relief valve, hydraulic-control butterfly valve, air vessel, air valve, and other water hammer protection measures is numerically simulated and calculated, and the effectiveness of the range method is analyzed, to ensure a waterproof hammer in pump stop accidents. The results show that the main factors affecting the effect of water hammer protection under the two-stage valve-closing parameters of the hydraulic-control butterfly valve are the fast-closing angle and the slow-closing time. The arrangement of the air vessel behind the pump can effectively increase the minimum water hammer pressure in the climbing section, and with the increase of the volume of the air vessel, the pump reverse speed and the maximum positive pressure increase slightly, but the overall water hammer protection effect is better. With the increase of the moment of inertia of the motor, the maximum positive pressure and minimum negative pressure of the pipeline still do not meet the requirements of the specification, and the modification cost is relatively large. The combination of the one-stage hydraulic-control butterfly valve, the air valve, the air vessel, and the water hammer relief valve can effectively reduce the volume of the air vessel. Under the optimal method, the maximum positive pressure head is 236.61 m, and the minimum negative pressure head is −3.18 m. Compared with the original method, the maximum positive pressure head is increased by 1.18%, the minimum negative pressure head is reduced by 95.78%, the maximum reverse speed of the pump is reduced by 100%, and the maximum reverse flow of the pump is reduced by 70.27%, meeting the requirements of water hammer protection. This is a safe and economical protection method. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic highlighted the need for agile governance to effectively address and prevent future global crises. Scholars have examined China's grid system and its application by local governments in controlling the spread of COVID-19. Our research supports these findings, and we further argue that the grid system enhances responsiveness, inclusiveness, and transparency in governance, thereby benefiting both the government and its citizens. Through a detailed case study of grid governance in the M District of Shanghai from July 2020 to August 2022, we explore the operational mechanisms of the grid system. By incorporating the safety valve theory, we propose that the community grid, the smallest administrative unit in China, functions as an institution to issue pre-emptive warnings, integrate communities, and alleviate pressures during times of crisis, contributing to governance agility. As grid governance has constantly been strengthened, this research not only advances our comprehension of the effectiveness of grassroots governance in China, but also offers valuable insights pertaining to crisis management in mega-cities worldwide. [ABSTRACT FROM AUTHOR]

The paper presents an overview of the efficiency for a hydraulic circuit with 4/2-way hand-lever valves. Thereby in this article we are studying three hydraulic circuits which contain 4/2-way hand-lever valves. The first hydraulic circuit contains the following devices: pump unit, tank, 4/2-way hand-lever valve, throttle valve, double acting cylinder (Dou 1-1). The second hydraulic circuit contains the following components: pump unit, tank, 4/2-way hand-lever valve, pressure relief valve, double acting cylinder (Dou 2- 1), and 2-way flow control valve. The last circuit, which is actually a hydraulic system, contains the following components: pump unit, tank, 4/2-way hand-lever valve, non-return valves, 2-way flow control valve, double acting cylinders (Dou 3-1 and Dou 3-2). [ABSTRACT FROM AUTHOR]

Electron flow through the electron transport chain (ETC) is essential for oxidative phosphorylation in mitochondria and photosynthesis in chloroplasts. Electron fluxes depend on environmental parameters, e.g., ionic and osmotic conditions and endogenous factors, and this may cause severe imbalances. Plants have evolved alternative sinks to balance the reductive load on the electron transport chains in order to avoid overreduction, generation of reactive oxygen species (ROS), and to cope with environmental stresses. These sinks act primarily as valves for electron drainage and secondarily as regulators of tolerance‐related metabolism, utilizing the excess reductive energy. High salinity is an environmental stressor that stimulates the generation of ROS and oxidative stress, which affects growth and development by disrupting the redox homeostasis of plants. While glycophytic plants are sensitive to high salinity, halophytic plants tolerate, grow, and reproduce at high salinity. Various studies have examined the ETC systems of glycophytic plants, however, information about the state and regulation of ETCs in halophytes under non‐saline and saline conditions is scarce. This review focuses on alternative electron sinks in chloroplasts and mitochondria of halophytic plants. In cases where information on halophytes is lacking, we examined the available knowledge on the relationship between alternative sinks and gradual salinity resilience of glycophytes. To this end, transcriptional responses of involved components of photosynthetic and respiratory ETCs were compared between the glycophyte Arabidopsis thaliana and the halophyte Schrenkiella parvula, and the time‐courses of these transcripts were examined in A. thaliana. The observed regulatory patterns are discussed in the context of reactive molecular species formation in halophytes and glycophytes. [ABSTRACT FROM AUTHOR]

In recent literature, aqueous formate/bicarbonate has been proposed as a safer alternative hydrogen storage system under normal operating conditions. In the present work, a preliminary quantitative risk assessment is presented for the first time on a standard tank for hydrogen storage containing aqueous formate mixture invested by an external fire. The results are compared to compressed hydrogen tanks at 350 bar as a benchmark. Frequency and consequence analysis were used to build risk maps. Results show that aqueous formate storage is intrinsically safer in the case of catastrophic failure of the vessel, due to the presence of water in the system as well as in the case of continuous release from safety valves, because of the lower operating pressure required in the storage vessel. [Display omitted] • Aqueous formate mixtures are an intrinsically safer hydrogen storage technology. • Water can prevent ignition and reduce thermal radiation in case of fires. • Smaller areas are affected by accidents compared to traditional pressurized H 2. • Water can also drastically reduce risks in the case of confined explosions. [ABSTRACT FROM AUTHOR]

A spillway is a significant structure that releases the exceeded water during extreme flood events. It is considered as a safety valve during dams operating. Spillway location at dam body is one of the most important requirements of dam design. Different locations may influence the flow patterns which lead to change in the hydraulic performance of the spillway. In this paper, a numerical model was presented utilizing the Ansys fluent software using the realizable k-ɛ turbulence model to investigate the flow patterns of Mandali Dam's spillway at different locations. The interaction between air and water phases was simulated by using volume of fluid (VOF) model. Moreover, cavitation damage was studied for different flow discharges values. the validation of the numerical model was executed in compression with the measurement of the physical model. A discharge of 1800 m3/s was utilized for validation, while five different discharges; 1800, 1300, 1040, 440, and 67 m3/s were employed to investigate the hydraulic properties. The results show an agreement between numerical model and the physical model. According to the hydraulic properties, the spillway location at the center of the dam is better than its location at the edge of the dam. The discharge coefficient value in scenario one was found to be closer to the physical model value compared to the second scenario. At discharge 1800 and 1300, the discharge coefficient was 2.02 and 1.72, while in scenario two it was 1.46 and 1.21 in comparison with physical model which was 2.06 and 1.99. For cavitation investigations, the numerical model shows that the spillway is safe with no cavitation effects for the whole applied discharge values. [ABSTRACT FROM AUTHOR]

Non-photochemical quenching (NPQ) is a protective mechanism used by plants to safely dissipate excess absorbed light energy as heat, minimizing photooxidative damage. Although the importance of NPQ as a safety valve for photosynthesis is well-known, the physiological and environmental effects of the heat produced remain unclear because the amount of heat produced by NPQ is considered negligible, and its physiological effects have not been directly observed. Here, we calculated the heat produced by NPQ and evaluated its impact on the leaf and global warming based on simplified models. Our evaluation showed that the heat produced by NPQ in a given leaf area is 63.9 W m-2 under direct sunlight. Under the standard condition, NPQ warms up the leaf at less than 0.1°C, but it could be 1°C under particular conditions with low thermal conductance. We also estimated the thermal radiation of vegetation's NPQ to be 2.2 W m-2 par global averaged surface area. It is only 0.55% of the thermal radiation by the Earth's surface, but still significant in the current climate change response. We further discuss the possible function of NPQ to plant physiology besides the safety valve and provide strategies with artificial modification of the NPQ mechanism to increase food production and mitigate global warming. [ABSTRACT FROM AUTHOR]

This study proposes an innovation, which is to use a non-circular and bio-inspired forced conduit (a new penstock with a cross section inspired by a tree trunk), to control the effects of hydraulic transients in Brazilian small hydropower plants (SHPs). The aim is to demonstrate that natural structures, adapted to periodic environmental disturbances, are better at hydraulic transient control than traditional conduits. The proposed methodology includes the following steps: (1) problem identification; (2) potential biological model identification; (3) development of alternatives; (4) implementation and testing; and (5) solution selection. This research was conducted at the São Tadeu I SHP, in the city of Santo Antônio de Leverger/MT, Brazil. The following tree biological models from the Brazilian savannah (Cerrado) were used: Handroanthus capitatus and Strychnos pseudoquina. The proposed innovation improves the conduit of the traditional circular section and the relief valve solution of the criteria studied. The reason for this improvement was the reduction of wave speed in the non-circular section (from 1126 to 583 m s−1). [ABSTRACT FROM AUTHOR]

Teagasc, the state agency for research, training and advice, and the Department of Agriculture, Food and the Marine (DAFM) have collaborated on the development of a testing protocol for <3m boom sprayers in Ireland. An informal survey indicated that there was an array of <3m boom sprayers on the Irish markket with varying specifications. From that survey and examination of sprayers with varying specifications, this paper presents the range of equipment and some of the problems encountered. The issues varied from basic like no basket filter, but some were more complex like the layout of the plumbing systems, the type and size of pumps, the lack of control, pressure adjustment, relief valves etc. A challenging factor for testing is that frequently these sprayers when sold for mounting on a Quad type ATV are sold as two seperate parts. The units are not that expensive so the test cost needs to be pitched so that it does not encourage immediate replacement with a new sprayer, which could result in new sprayers that would not pass a test continually replacing older models avoiding the test procedure. Also the sprayer and the boom are not being sold as one unit. One box contains the spray tank and lance, and as this is not a boom sprayer is does not require to be tested. The second item is a boom which can be attached to the spray tank and lance, and it is only when the boom is attached that the unit falls into the requirement for a test. So if a farmer only requires to have his machine tested after 3 years can he buy a new boom or alternatively a new spray tank unit and then exempt himself from the test. [ABSTRACT FROM AUTHOR]

Pulsing emanations of native hydrogen (H 2) have been observed at the surface of emitting structures, specifically "Fairy circles" in Minas Gerais State, Brazil. However, the underlying cause of these H 2 pulses remains unclear. Possible controlling factors include deep migration processes, interactions with the atmosphere and near-surface conditions. In this study, we examine the mechanisms that may trigger pulsating fluid migration and the resulting periodicity, with particular attention to the influence of deep geological processes. We employed a numerical model to simulate the migration of a constant deep fluid flow. To ensure the accuracy of the model in solving complex fluid flows, we conducted initial simulations to compare the morphology and amplitude of 2D thermal anomalies induced by buoyancy-driven water flow within a fault zone with another numerical model. Following the validation of our model in capturing complex fluid flows, we proceeded to model the H 2 gas flow along a 1-km draining fault, intersected by a low permeable rock layer acting as a "pressure relief valve" system. Our objective is to investigate the conditions that give rise to a pulsing regime. Our results indicate that sustained surface bursts in the model only occur if: (I) a permeability with an effective-stress dependency is considered, (II) a significant contrast in permeability exists between different zones, (III) an adequately high initial effective stress state is present at the base of the low-permeability layer, and (IV) the incoming and continuous fluid flow of H 2 at depth is sufficiently low to prevent instant "opening" of the low-permeability layer due to overpressure. The predicted periodicity for surface H 2 pulses regulated by the fault-valve mechanisms is expected to range from 100 to 300 days, representing a considerably longer duration compared to the measurements observed up to now in Brazilian Fairy circles. • Examined natural H 2 pulsing flow along a fault via numerical simulation. • H 2 pulse generation linked to stress-dependent deep permeability zones. • H 2 pulse intervals span months, longer than prior São Francisco basin data. [ABSTRACT FROM AUTHOR]

Layered ternary materials with high nickel content are regarded as the most promising cathode materials for high-energy-density lithium-ion batteries, owing to their advantages of high capacity, low cost, and relatively good safety. However, as the nickel content increases in ternary layered materials, their thermal stability noticeably decreases. It is of paramount importance to explore the characteristics of thermal runaway for lithium-ion batteries. In this study, two high-nickel LiNi0.9Co0.05Mn0.05O2 batteries were laterally heated to thermal runaway in a sealed chamber filled with nitrogen to investigate the thermal characteristics and gas compositions. The temperature of the battery tabs was measured, revealing that both batteries were in a critical state of thermal runaway near 120 degrees Celsius. A quantitative analysis method was employed during the eruption process, dividing it into three stages: ultra-fast, fast, and slow; the corresponding durations for the two batteries were 3, 2, 27 s and 3, 3, 26 s. By comparing the changes in chamber pressure, it was observed that both batteries exhibited a similar continuous venting duration of 32 s. However, the pressure fluctuation ranges of the two samples were 99.5 and 68.2 kPa·m·s−1. Compared to the other sample, the 211 Ah sample exhibited larger chamber pressure fluctuations and reached higher peak pressures, indicating a higher risk of explosion. In the experimental phenomenon captured by a high-speed camera, it took only 1 s for the sample to transition from the opening of the safety valve to filling the experimental chamber with smoke. The battery with higher energy density exhibited more intense eruption during thermal runaway, resulting in more severe mass loss. The mass loss of the two samples is 73% and 64.87%. The electrolyte also reacted more completely, resulting in a reduced number of measured exhaust components. The main components of gaseous ejections are CO, CO2, H2, C2H4, and CH4. For the 211 Ah battery, the vented gases were mainly composed of CO (41.3%), CO2 (24.8%), H2 (21%), C2H4 (7.4%) and CH4 (3.9%), while those for the other 256 Ah battery were mainly CO (30.6%), CO2 (28.5%), H2 (21.7%), C2H4 (12.4%) and CH4 (5.8%). Comparatively, the higher-capacity battery produced more gases. The gas volumes, converted to standard conditions (0 °C, 101 kPa) and normalized, resulted in 1.985 L/Ah and 2.182 L/Ah, respectively. The results provide valuable guidance for the protection of large-capacity, high-energy-density battery systems. The quantitative analysis of the eruption process has provided assistance to fire alarm systems and firefighting strategies. [ABSTRACT FROM AUTHOR]

The article discusses the challenges faced by researchers studying the decision-making processes within the British government during the Edwardian era and the early years of World War I. The lack of available cabinet meeting minutes and the limited information provided in the prime minister's correspondence with the monarch have hindered scholars' understanding of this period. However, the private papers and diaries of government ministers, particularly those of J.A. Pease, have provided valuable insights. The article praises the comprehensive and reliable account of Asquith's Liberal government presented in the recently published diaries of Pease, highlighting the editors' meticulous research and the wealth of primary sources used. The article concludes by calling for assistance in furthering the work of the Liberal Democrat History Group. [Extracted from the article]