Effect Of Pressure Research Articles

Effects of temperature and pressure on the limiting current density of PEM electrolysis cells based on a theoretical prediction model and experiments

Operation at high current density of polymer electrolyte membrane electrolysis cell (PEMEC) can reduce its electrode area and capital expense. The high current density operation is limited by the limiting current density (LCD), where electrolysis voltage abruptly increases. Effects of operating temperature and pressure on the LCD were evaluated in a lab-scale PEMEC within a range from 70 to 90 °C and from 0.1 to 0.3 MPa. Also, a theoretical model was developed to predict the LCD, and to clarify what determines LCD and how the operating conditions influence the LCD. The theoretical analysis suggests that when current density is close to the LCD, water mass transport at anode reaches a limitation, which indicates that water saturation reaches almost zero at anodic catalyst layer. The analysis also finds that lower operating temperature and higher operating pressure can reduce oxygen gas saturation and raise the water saturation in porous transport layer at anode, and finally enlarge the LCD.

Effect of perineal massage and gentle techniques on perineal rupture in primigravida maternity mothers

Background: Perineal rupture is a tear that occurs when a baby is born, either spontaneously or by using tools/actions. Preventive efforts can be made to reduce the risk of perineal rupture by massaging the perineum and using good pressure techniques during labor. Objective: To determine the effect of perineal massage techniques and pressure on perineal rupture in primigravida mothers who give birth. Method: This research uses experimental research methods; this type of research is quantitative with a pretest-posttest research design with a control group and an analytical study design with a retrospective approach. The total research sample required was 30 primigravidas, with details, namely 15 people from the perineal massage group and 15 from the gentle technique. Sampling was taken using an accidental sampling technique, where subjects were selected as research samples based on cases/respondents who happened to be available in a place according to the context. Results: research results of primigravid mothers who experienced perineal rupture in the perineal massage group were two people (20%), and in the menstrual technique group, there were eight people (80%), based on the results of data analysis using the Wilcoxon test, the p-value was obtained. In the perineal massage group, it was 0.000; in the gentle technique group, it was 0.005. Conclusion: It can be concluded that perineal massage is more effective than gentle techniques in preventing perineal rupture in primigravida mothers. To ensure the effectiveness of the chosen method, it is advisable to consult with medical personnel experienced in this field and follow the recommendations and protocols approved by the relevant health authorities. In addition, careful monitoring and care during labor is also essential to minimize the risk of perineal rupture.

Finite element analysis of a generalized rotating FGM vessel subjected to thermo-mechanical loadings: Effect of Poisson ratio and inhomogeneity parameters.

Cylinders and thick walled cylindrical shells are commonly utilized in several industries to transport and store fluids under certain pressure and temperature conditions. In the present paper, a numerical solution is developed in order to investigate displacement, temperature and stress fields in a rotating pressure vessel made of generalized functionally graded material (FGM) subjected to different thermo-mechanical boundary conditions. The aim is to investigate the effect of Poisson ratio, internal pressure and temperature and inhomogeneity parameters on the stress and deformation distributions of the rotating pressure vessel. The material is considered isotropic nonhomogeneous and linearly elastic with its properties varying along the radial direction. Additionally, certain conditions, such as exterior or interior problems where r → ∞ or r → 0, respectively, are impossible to resolve using the variation of attributes as a power-law distribution. An approach to the spatial Young modulus distribution that is more broad has been suggested in the literature which can be applied to such physical challenges. The rotation of the pressure vessel is considered in the analysis, and the temperature distribution is assumed to be non-uniform. Since an analytical solution to the differential equation is not accessible, the conventional Galerkin discretization approach of the Finite Element Method (FEM) is applied, nowadays is considered one of the main numerical tools for solving Boundary Value Problems (BVP). It is addressed how stress, strain, and displacement are affected by the inhomogeneity parameter, rotation speed, pressure, temperature, and Poisson ratio. The examination of the various findings indicates that changes in the temperature profile, rotation, and inhomogeneity parameter on the thermoelastic field have a substantial impact on the stress and strain in the FGM cylinder. The findings indicate that the Poisson ratio and inhomogeneity parameters have a significant impact on the stress and deformation distributions. According to the results, the above-mentioned parameters can be adapted to control the thermoelastic filed in a FGM cylinder. The present research offers significant perspectives on the development and enhancement of rotating FGM pressure vessels intended for high-temperature applications.

Arachnoid Cyst Burst in Presence of Contralateral Nomura IV Subdural Hematoma: After Effects of Traumatic Kickback and Intracranial Pressure

Intracranial arachnoid cysts are benign fluid-filled sacs located between the brain and the arachnoid membrane. Their rupture is an uncommon event, often associated with trauma or an underlying pathology. Here, we present a case of a 61-year-old woman with a ruptured arachnoid cyst coinciding with a contralateral subdural hematoma. The patient manifested a persistent headache, balance disorders and right facial paresthesia. Brain CT study showed a right temporo-polar cyst (known to the patient) and a right parietal chronic Subdural Hematoma (cSDH). Although the kickback may contribute to bursting or weakening of cyst integrity, the CT-density pattern of the cSDH, according to Nomura classification is to be considered associated with increased fibrinolysis activity and potentially with parenchyma compression. This case highlights the importance of considering arachnoid cyst rupture as a potential indirect consequence of head trauma kickback, particularly in the presence of contralateral intracranial hemorrhage.

Arachnoid Cyst Burst in Presence of Contralateral Nomura IV Subdural Hematoma: After Effects of Traumatic Kickback and Intracranial Pressure

Intracranial arachnoid cysts are benign fluid-filled sacs located between the brain and the arachnoid membrane. Their rupture is an uncommon event, often associated with trauma or an underlying pathology. Here, we present a case of a 61-year-old woman with a ruptured arachnoid cyst coinciding with a contralateral subdural hematoma. The patient manifested a persistent headache, balance disorders and right facial paresthesia. Brain CT study showed a right temporo-polar cyst (known to the patient) and a right parietal chronic Subdural Hematoma (cSDH). Although the kickback may contribute to bursting or weakening of cyst integrity, the CT-density pattern of the cSDH, according to Nomura classification is to be considered associated with increased fibrinolysis activity and potentially with parenchyma compression. This case highlights the importance of considering arachnoid cyst rupture as a potential indirect consequence of head trauma kickback, particularly in the presence of contralateral intracranial hemorrhage.

Shallow-donor impurity states in type-II InGaN-ZnSnN2/GaN quantum wells under hydrostatic pressure effect

Shallow-donor impurity states in type-II InGaN-ZnSnN2/GaN quantum wells under hydrostatic pressure effect

The Double-Edged Sword Effect of Performance Pressure on Employee Boundary-Spanning Behavior

The Double-Edged Sword Effect of Performance Pressure on Employee Boundary-Spanning Behavior

Erratum to: Effect of ambient pressures on laser-induced breakdown spectroscopy signals

Erratum to: Effect of ambient pressures on laser-induced breakdown spectroscopy signals

Impact of pressure on coking of vacuum residue

AbstractThermal conversion of vacuum tower bottoms (VTB) and its narrow‐cut distillation fractions were studied at 530°C between 0.1 and 2 MPa pressure to assess the effect of the reaction pressure on coking. Coke yield in the VTB conversion increased with pressure, which was found to be mostly due to the enhanced coking of the 700°C+ narrow cut. The microcarbon residue in the liquid remained unaffected. The yield of products with a boiling point below 510°C, including distillate and by‐product lights, decreased with the pressure increase. The trend was a cumulative effect of the increased yields from the VTB cuts boiling below 635°C and the decreased yields from the heavier cuts. Admixing different VTB cuts into the VTB feed resulted in the weighted average changes with no synergistic or antagonistic effects.

Effect of continuous positive airway pressure helmet on respiratory function following surgical procedures in brachycephalic dogs: A randomized controlled trial.

To evaluate the effect of continuous positive airway pressure (CPAP) on respiratory function in the early postoperative period of brachycephalic dogs. Prospective, randomized clinical trial. A total of 32 dogs. Dogs were assigned to recover with or without CPAP (control) and assessed at specific time points over 1 h. Treatment was discontinued for dogs with a CPAP tolerance score of 3 or more (from a range of 0-4). The primary outcome was pulse oximetry (SpO2). Secondary outcomes were arterial O2 pressure (PaO2)/FiO2 ratio (PaO2/FiO2), arterial CO2 pressure (PaCO2), and rectal temperature. For dogs that reached a CPAP tolerance score of 3 or more, only the data collected up to the time point before discontinuation were included in the analysis.The treatment effect (β) was analyzed using random effects models and the results were reported with 95% confidence intervals. Dogs were assigned randomly to each protocol. Baseline characteristics in both groups were comparable. Arterial blood gases were obtained in seven control group dogs and nine CPAP group dogs. Treatment did not affect SpO2 (β = -0.1, -2.1 to 2.0) but affected the PaO2/FiO2 ratio (β = 58.1, 2.6 to 113.6), with no effects on PaCO2 (β = -4.3, -10.5 to 1.9) or temperature (β = 0.4, -0.8 to 1.6). In postoperative brachycephalic dogs, CPAP had no effect on SpO2 but improved the PaO2/FiO2 ratio in brachycephalic dogs postoperatively. Continuous positive airway pressure offers a valuable solution to improve gas exchange efficiency, a prevalent concern in postoperative brachycephalic dogs, with the potential to enhance overall outcomes.

Fluid Structure Interaction Analyses of Elevated Storage Tank under Seismic Load

Elevated storage tanks are used to store fresh and waste water, cereal, oil and petrochemical materials. Therefore they serve in a wide area of utilization in this day and age. Analysis of a half full with water elevated storage tank is performed in the scope of this study. The structure is composed of a steel circular storage tank and frame typed steel stager. The structure is under the effect of earthquake loads as well as operational ones. Numerical model is generated by Finite Elements Analysis (FEA) software including fluid and structure parts. The interaction of the parts is provided by Coupled Eulerian Lagrangian (CEL) technique. While the structure constitutes the Lagrangian part, the fluid constitutes the Eulerian part. Interaction of Eulerian and Lagrangian parts are provided by general contact algorithms. Free surface movement of the water, maximum displacements and natural frequency values with related mode shapes of the structure are obtained after numerical analysis. Numerical results are verified by semi-analytical model, where the structure is modelled as single degree of freedom system. The accordance between results is numerically and visually obtained. The turbulent movement of water under the influence of an earthquake is modelled by utilizing the CEL technique. So, the effect of the dynamic pressure induced by the turbulence on the tank and the structural system has been taken into consideration.

Coarse-grained force field for ZIF-8: A study on adsorption, diffusion, and structural properties.

Metal-organic frameworks (MOFs) are revolutionizing a spectrum of industries, from groundbreaking gas storage solutions to transformative biological system applications. The intricate architecture of these materials necessitates the use of advanced computational techniques for a comprehensive understanding of their molecular structure and prediction of their physical properties. Coarse-grained (CG) simulations shine a spotlight on the often-neglected influences of defects, pressure effects, and spatial disorders on the performance of MOFs. These simulations are not just beneficial but indispensable for high-demand applications, such as mixed matrix membranes and intricate biological system interfaces. In this work, we propose an optimized CG force field tailored for ZIF-8. Our work provides a deep dive into sorption isotherms and diffusion coefficients of small molecules. We demonstrate the structural dynamics of ZIF-8, particularly how it responds to pressurization, which affects its crystal structure and leads to local changes in aperture size and area. Emphasizing the game-changing potential of CG simulations, we explore the characteristics of amorphization in ZIF-8. Through computational exploration, we aim to bridge the knowledge gap, enhancing the potential applications of nanoporous materials for various applications.

Mechanical Modeling of Viscous Fluid Damper with Temperature and Pressure Coupling Effects

During long-duration dynamic loads, such as wind loads or seismic effects, the internal temperature and pressure of a damping cylinder escalate rapidly, which induce shifts in the mechanical attributes of viscous fluid dampers (VFDs). This study investigated the mechanical performance of VFD considering the coupling effects of temperature and pressure under long-duration loads. First, we analyzed the mechanical and energy-dissipation performances of the dampers based on the dynamic mechanical tests considering different loading frequencies, displacement amplitude, and loading cycles. The experimental results indicated that both temperature and pressure influenced the output of the dampers, and in the sealed environment of the damper pip, temperature and pressure exerted mutual influence. Furthermore, the relationship between the damping coefficient and temperature–pressure coupling effects was obtained. Subsequently, an improved mathematical model for the mechanical performance of a gap-type VFD was proposed by considering the macroscopic energy balance of the entire fluid within the damper. Finally, the accuracy of the mathematical model for VFD under long-duration dynamic loads was validated by comparing the computational results with the experimental data.

Impact of regulatory, normative and cognitive institutional pressures on rural agribusiness entrepreneurial opportunities and performance: empirical evidence from Ghana

Abstract Entrepreneurs in the agribusiness sector in Ghana encounter numerous challenges due to the weak institutional framework in the country. This often leads to business failure and poor performance of agribusiness ventures. In this paper, we aim to highlight the significance of institutional support for agribusiness entrepreneurs and its crucial role in creating more opportunities for farm entrepreneurs and ensuring the success of farm ventures. The study analyzes empirical data collected from 246 maize farm entrepreneurs in Ghana using the Structural Equation Modelling technique (PLS-SEM). The findings show that regulatory and cognitive institutions have a more positive significant influence on the opportunity recognition and exploitation strategies of maize farm entrepreneurs. Both opportunity recognition and exploitation partially mediate the effects of regulatory, normative and cognitive institutional pressures and farm business performance. The study suggests that maize farm entrepreneurs appear to benefit from regulatory and cognitive institutions. The findings, therefore, have strong policy relevance. The results of this study contribute significantly to food policy aimed at boosting maize supply chain business and food security.

Study on the ceiling gas temperature distribution, fire merging, and flame length induced by twin tunnel fires under reduced pressures

A comprehensive understanding of the development characteristics of multiple fires in tunnels holds significant importance in estimating the thermal safe distance required for both people and facilities. In this paper, a series of numerical and experimental works are performed to examine the ceiling gas temperature, fire merging, and flame length of twin fires in a tunnel. Varied thermal hazard scenarios were simulated by altering the ambient pressure, heat release rate, and pool spacing. The findings indicate that as the ambient pressure reduces, the air entrainment coefficient decreases, resulting in a higher ceiling gas temperature. Large pool spacings demonstrate two peak impact points in ceiling gas temperature. However, as the pool spacings decrease further, only one peak impact point appears above the center of two fire sources. As pressure mounts, the low-oxygen zone at the tunnel ceiling contracts progressively, and it primarily appears in the additional region between two fire sources. The temperature processing method is adopted to determine the fire merging and flame length. The fire merging probability is predicted by introducing a piecewise model. Furthermore, a physical model is proposed based on the air entrainment theory to establish the relationship between flame length and the effects of pool spacing, ambient pressure, and heat release rate, which can be applied to both open spaces and tunnels.

Recovery and immune function after low pressure pneumoperitoneum during robot-assisted radical prostatectomy: a randomised controlled trial.

To compare the effectiveness of low intra-abdominal pressure (IAP) facilitated by deep neuromuscular block (NMB) to standard practice in improving the quality of recovery, preserving immune function, and enhancing parietal perfusion during robot-assisted radical prostatectomy (RARP). In this blinded, randomised controlled trial, 96 patients were randomised to the experimental group with low IAP (8 mmHg) facilitated by deep NMB (post-tetanic count 1-2) or the control group with standard IAP (14 mmHg) and moderate NMB (train-of-four 1-2). Recovery was measured using the 40-item Quality of Recovery questionnaire and 36-item Short-Form Health survey. Immune function was evaluated by plasma damage-associated molecular patterns, cytokines, and ex vivo lipopolysaccharide-stimulated cytokine production. Parietal peritoneum perfusion was measured by analysing the recordings of indocyanine-green injection. Quality of recovery was not superior in the experimental group (n = 46) compared to the control group (n = 50). All clinical outcomes, including pain scores, postoperative nausea and vomiting, and hospital stay were similar. There were no significant differences in postoperative plasma concentrations of damage-associated molecular patterns, cytokines, and ex vivo cytokine production capacity. The use of low IAP resulted in better parietal peritoneum perfusion. Despite better perfusion of the parietal peritoneum, low IAP facilitated by deep NMB did not improve the quality of recovery or preserve immune function compared to standard practice in patients undergoing RARP.

#621 The effect of intra-operative mean arterial pressure on early graft function in deceased donor kidney transplantation

Abstract Background and Aims The adequate perfusion pressure to the graft is essential for proper graft function in kidney transplantation, especially in deceased donor kidney transplantation. In particular, Mean arterial pressure (MAP) during operation can affect early graft function because MAP is associated with renal blood flow and glomerular filtration rate. Therefore, the analysis of intra-operative parameters are necessary to evaluate adequate graft perfusion. The aim of this study is to investigate the relationship between intra-operative parameters including MAP and early graft function in deceased donor kidney transplantation. Method We retrospectively analyzed 363 recipients who underwent deceased donor kidney transplantation from March 2010 to December 2020. Anesthetic monitoring data during intraoperative period was analyzed and basic clinical parameters were evaluated. Results In total 363 recipients, the mean recipient age was 48.9 ± 10.3 and mean donor age was 48.2 ± 15.2. Anesthetic time was mean 285.9 ± 63.8 (min) and operation time was 226.4 ± 48.7 (min). Median value of baseline MAP and MAP at reperfusion were 124 mmHg and 88 mmHg. After initial analysis, the recipients were divided into two groups, high MAP group (n = 185) and low MAP group (n = 178), according to median value of baseline MAP (124 mmHg) and these two groups were analyzed. High MAP group showed higher estimated glomerular filtration rate (eGFR) and urine output compared to low MAP group during immediate postoperative 1 week. At postoperative day 5, eGFRs were 43.4 ± 26.7 and 37.3 ± 24.2 mL/min/1.73 m2 respectively (p = 0.022) and urine outputs were 2942.6 ± 1368.6 and 2474.3 ± 1199.1 mL respectively (p = 0.001). The incidences of delayed graft function showed no significant difference between two groups (2.2% vs 6.2%, p = 0.066). We additionally analyzed the effect of MAP at reperfusion, and the result showed that there was no significant relationship between MAP at reperfusion and early graft function. Conclusion In this retrospective study, MAP at reperfusion was not significantly related to early graft function and incidence of delayed graft function. In baseline MAP analysis, high baseline MAP group showed early recovery of eGFR and more urine output than low baseline MAP group. As a result, the recipients with high baseline MAP were related to early recovery of graft function in deceased donor kidney transplantation.

Can Pressure be a Good Strategy for Optimizing Thermoelectric Performance of SnPS3${\rm SnPS}_3$?

AbstractExternal pressure can significantly alter the transport coefficients, power factor, and figure of merit because of its direct influence on the electronic structure, electron–phonon, and phonon–phonon couplings. This study delves into the electronic and thermal transport properties of at external pressures up to 30 GPa using first‐principles calculations and Boltzmann transport theory. The electron–phonon relaxation time is computed within the electron–phonon‐averaged (EPA) approximation, enabling exploration beyond the constant relaxation time approximation. The first‐principles calculations reveal an indirect bandgap of 1.76 (without pressure) and 0.12 eV (30 GPa). The density functional perturbation theory calculations confirm the dynamic stability of at external pressure up to 30 GPa. The electronic transport properties are improved by more than one order of magnitude at 30 GPa, consistent with experimental observations. The Peierls–Boltzmann transport calculations demonstrate the room temperature lattice thermal conductivity of 0.22 (without pressure) and 7.4 (at 30 GPa). The results emanate that exhibits of 0.71 at 900 K at a hole doping of 2 at zero pressure, which decreases with increasing pressure. The findings explore the effect of external pressure on both electronic and thermal transport properties of , warranting further experimental exploration of thermal transport properties at higher pressures.

#1105 Prognosis of dialysis patients with obstructive sleep apnea syndrome diagnosed by polysomnography

Abstract Background and Aims Obstructive Sleep Apnea Syndrome (OSA) is common among CKD, in particular dialysis patients. However, it is not yet studied in a large polysomnography (PSG) database. Randomized controlled trials (RCTs) proved the effectiveness of continuous positive airway pressure (CPAP) for the SAS-related symptoms, but not for lowering the mortality risk of all-cause and cardiovascular disease. However, the effect of CPAP on mortality risk is not examined among dialysis patents. Method We identified dialysis patients by reviewing medical records in the Okinawa Nakamura Clinic (ONSLEEP). (J Clin Sleep Med 2021). In the ONSLEEP, a total of 10,856 Japanese patients received PSG from September 1990 to December 2010. We defined patients who were on CPAP more than one month as CPAP user. Patients qualified and eligible for CPAP but refused it were assigned as CPAP non-users. Median observation was 6.6 years. We studied 9,841 PSG patients after excluding those with insufficient data, age<20 years, and central SAS. Among them, we found 195 dialysis patients: 16 (1.0%) dialysis patients with AHI<5/hour in 1,665 subjects and 164 (2.5%) in 8,176 OSA patients. Mortality rate was compared between CPAP users and nonusers by multivariate logistic analysis adjusted for age, gender, body mass index (BMI), and apnea hypopnea index (AHI). Results Among the OSA dialysis patients (men 127, women 37), there were 116 (2.6%) in the CPAP users and 48 (2.2%) in the CPAP non-users, respectively. Number of deaths was 65 (39 CPAP users, 26 CPAP non-users) during the follow-up. The death rate was 33.6% in the CPAP users and 54.2% in the CPAP non-users, respectively. CPAP users showed better survival after starting dialysis; hazard ratio (HR) 0.52 and 95% confidence interval (CI) of 0.31 to 0.88 (P = 0.015). Age was also a significant predictor of death; HR (95% CI) 1.04 (1.02-1.06, P < 0.0001). Conclusion Dialysis patients with OSA showed better survival by use of CPAP. In dialysis patients, screening of OSA is recommended if they complained sleep problems such as insomnia, daytime sleepiness, headache, and fatigue. Also, we need further study for those CPAP nonusers.

Crystallization of Y3Fe5O12 thin films on silicon photonic waveguides using CO2 laser annealing

We report the local crystallization of Y3Fe5O12 (YIG) thin films grown on Si substrates, and SOI waveguides by CO2 laser annealing (LA). The effect of laser power and oxygen pressure on the crystal structure of YIG films was systematically studied. Laser power dominated the YIG film crystallinity, while oxygen partial pressure during LA strongly influenced the crystal grain size and magnetic anisotropy. Fully crystallized YIG thin films with pure garnet phases were fabricated by LA. The refractive index n and extinction coefficient k were comparable to thin films fabricated by rapid thermal annealing (RTA). Propagation loss measured at 1550 nm wavelength on YIG/SOI waveguides and YIG/SiN ring resonators were comparable to RTA annealed films, promising device development for silicon photonics.