Effect Of Pressure Research Articles

Study on the effect of geometry and material property on collapse pressure of a helical steam generator tube under external pressure

In this paper, a numerical study was conducted to analyze the effect of the geometry (tube thickness, ovality, and helical diameter) and material properties of once through steam generator tubes subjected to external pressure on collapse pressure. The outer diameter of the steam generator tube was fixed at 17 mm, and the tube thickness was changed to 2.5 mm, 2.29 mm, and 1.27 mm. Ovality was considered for three cases of 0 %, 4 %, and 8 %, and three cases for helical diameter were considered: 577 mm, 937 mm, and 1297 mm. As material properties, elastic perfectly plastic property that ignores plastic hardening and real material property that reflect plastic hardening were considered. At the helical diameter (Dm/do ≥ 34) considered in this paper, the effect of collapse pressure due to helical bending did not appear on ovalities and both material properties. On the other hand, the wall thickness affected the collapse pressures according to the material properties when ovality occurred (>0 %). This is explained because the collapse mechanism varies depending on the thickness.

The Response of the Earth Magnetosphere to Changes in the Solar Wind Dynamic Pressure: 1. Plasma and Magnetic Pressures

AbstractIn the present study, the influence of the solar wind dynamic pressure on the plasma and magnetic pressures of the magnetosphere is studied. We use 11‐year Time History of Events and Macroscale Interactions during Substorms (THEMIS) instruments for plasma and magnetic field measurements in the magnetosphere and the OMNI database for solar wind dynamic pressure and IMF data. We focus on the effects of the solar wind dynamic pressure (PSW) and consider only times in which the interplanetary magnetic field (IMF) components are within ±5 nT. We find that the plasma pressure inside the magnetosphere follows the solar wind dynamic pressure and that an increase in PSW also influence the day‐night pressure asymmetry. Our analysis also reveals the existence of ion and electron drifts from midnight toward the dusk and dawn sectors, respectively. We observe a local magnetic pressure minimum located near a plasma pressure maximum at around 11 RE on the nightside. Comparing the effect of PSW on both plasma and magnetic pressures, we observe trends which are consistent with the diamagnetic properties of plasmas. In general, the distribution of plasma pressure within the Earth's magnetosphere is an important criterion for evaluating the magnetostatic equilibrium and electric current system. The outcome of this study should provide additional methodologies for the characterization of key plasma characteristics within the magnetosphere.

Research on erosion wear law of four-way flow channel of wellhead fracturing in ultra-deep wells

Abstract This paper establishes a 1/2 three-dimensional finite element model that considers multiple factors affecting the erosion rate of the four-way fracturing structure on site. The model can simulate the effects of different inlet velocities, dynamic viscosities, outlet quantities, outlet pressures, and channel wall angles on the velocity and streamline distribution of the four-way channel. It is also possible to analyze the effects of different factors such as inlet velocity, sand carrying mass flow rate, inlet quantity, fluid dynamic viscosity, fracturing fluid particle density, fracturing fluid particle diameter, four-way wall hardness, and channel wall inclination angle on the erosion of the inner wall. Through the established model calculation, it was found that as the inlet flow velocity increases, the maximum flow velocity in the channel also increases, and the value is close to 1.8 times the inlet velocity, with the maximum value appearing at the inlet corner. When the inlet velocity of the four-way valve is low, a significant vortex-like flow field appears in the closed flow channel of the four-way valve, which will lead to the accumulation of particles in the fracturing fluid. The calculation shows that the number and velocity of sand containing fracturing fluid inlets have the greatest impact on the erosion rate of the four-way flow channel, and the optimal inclination angle of the flow channel is 9 degrees. Increasing the hardness of the four-way wall can improve the maximum erosion rate of the flow channel wall, but changing the sand particle density and diameter has little significance in reducing the erosion rate of the four-way flow channel. It is recommended to perform corresponding heat treatment on the inner wall of the four-way valve to reduce the impact of sand containing fracturing fluid on wall erosion. This article provides a theoretical basis and guidance for controlling or avoiding erosion and thinning failure of four-way valves and also provides a theoretical basis for the design of wellhead four-way valves and various safe construction operations.

Effectiveness of multimedia-based teaching on the learning rate of anesthesia technologist students in the field of central venous pressure monitoring: A comparative study

BACKGROUND: Traditional teaching methods alone are no longer sufficient to meet the needs of modern societies. This study aimed to compare the effectiveness of central venous pressure teaching through multimedia and lecture method on learning rate of anesthesia technologist students. MATERIALS AND METHODS: In this quasi-experimental study, 41 undergraduate students of anesthesia technologist were selected through the census method and randomly divided into two groups: multimedia- and lecture-based teaching. The educational content was the same for both groups and was taught by the same educator. A pre-test was administered to both groups, and a post-test was conducted two weeks after the intervention. The data were analyzed using descriptive statistics, independent t-test, and paired t-test with SPSS software version 26. RESULTS: Before the intervention, there was no significant difference in the mean scores between the two groups (P = 0.648). However, after the intervention, the learning rate significantly improved in both teaching methods (P < 0.001). Furthermore, the mean scores obtained from post-test increase in the multimedia-based group were significantly higher than the lecture-based group (P = 0.004). CONCLUSION: The results of this study indicate the effectiveness of both methods. However, considering the advantages of multimedia-based teaching, such as responding to various learning styles and higher mean scores obtained from post-test of the multimedia-based group compared to the lecture-based group, it is recommended to utilize this teaching method in medical science courses.

Flight behaviour diverges more between seasonal forms than between species in Pieris butterflies.

In flying animals, wing morphology is typically assumed to influence flight behaviours. Whether seasonal polymorphism in butterfly morphology is linked to adaptive flight behaviour remains unresolved. Here, we compare the flight behaviours and wing morphologies of the spring and summer forms of two closely related butterfly species, Pieris napi and P. rapae. We first quantify three-dimensional flight behaviour by reconstructing individual flight trajectories using stereoscopic high-speed videography in an experimental outdoor cage. We then measure wing size and shape, which are characteristics assumed to influence flight behaviours in butterflies. We show that seasonal, but not interspecific, differences in flight behaviour might be associated with divergent forewing shapes. During spring, Pieris individuals are small and have elongated forewings, and generally fly at low speed and acceleration, while having a high flight curvature. On the contrary, summer individuals are larger and exhibit rounded forewings. They fly at high speed and acceleration, while having high turning acceleration and advance ratio. Our study provides one of the first quantitative pieces of evidence of different flight behaviours between seasonal forms of two Pieris butterfly species. We discuss the possibility that this co-divergence in flight behaviour and morphology is an adaptation to distinct seasonal environments. Properly identifying the mechanisms underpinning such divergence, nonetheless, requires further investigations to disentangle the interacting effects of microhabitats, predator community, parasitoid pressure and behavioural differences between sexes.

The effect of hydrostatic pressure, temperature and impurity factor on linear and nonlinear optical properties of InxGa1-xAs tuned quantum dot with modified Gaussian potential under the action of a vertical magnetic field

This study presents a detailed theoretical analysis of the effects of hydrostatic pressure, temperature, impurity factors, and external electric fields on the optical properties of InxGa1-xAs tuned quantum dot. A uniform magnetic field, directed perpendicular to the quantum dot plane, is applied. The system is excited using a monochromatic electromagnetic field, considering electron intersubband transitions. Energy levels and wave functions are determined using the parabolic band approximation and effective mass approximation. The linear and nonlinear optical absorption coefficients and refractive index changes are computed using the compact-density matrix approach and the iterative method. Numerical results indicate that the peaks of the linear and nonlinear optical absorption coefficients and refractive index changes shift towards lower energies (red shift) and higher energies (blue shift) under varying hydrostatic pressure, temperature, and impurity factor strength. Additionally, the peak values of the absorption coefficients and refractive index changes increase or decrease based on these parameter variations. These results have significant implications for the design and optimization of quantum dot-based optoelectronic devices.

Effect of Ir growth pressure on the domain wall dynamics in Ta/Pt/Co/Ir/Ta stacks

Effect of Ir growth pressure on the domain wall dynamics in Ta/Pt/Co/Ir/Ta stacks

Effects of H2 on microstructures of Cr2O3 scales grown in water vapour and consequences for breakaway

Model alloy, Fe-20Cr (wt%), was exposed in Ar-(5, 20)H2O, Ar-(5, 20)H2O-5H2 and Ar-20O2 (vol%) at 750 and 850 °C. The alloy formed Cr2O3 scales plus Fe-rich oxide nodules in H2O-containing gases, but a Cr2O3 scale in Ar-20O2 at 750 °C. The alloy formed an outer (Cr,Fe)-rich oxide layer and an inner, porous Cr2O3 layer in Ar-5H2O-5H2, whereas a dense Cr2O3 scale grew in Ar-5H2O at 850 °C. Application of Wagner’s theory successfully differentiated effects of oxide grain sizes and oxygen partial pressures of gases on scaling rates. Chemically inert SiO2 markers showed that Cr2O3 scales grew by outward metal diffusion.

Crack layer modeling of butt-fusion joints induced slow crack growth in high-density polyethylene pipes

The design and reliability of high-density polyethylene (HDPE) pipes can be dictated by the damage tolerance of their butt-fusion joints. A slow crack growth (SCG) model based on the crack layer theory for HDPE pipes internal and external circumferential and butt-fusion joints cracks is developed to investigate the discontinuous SCG behavior and lifetime tf variations. Using the developed model, the discontinuous SCG patterns, jump lengths and lifetime tf can be accurately simulated. In addition, the effects of pipes standard dimension ratio, internal pressure, and temperature on the SCG behavior and tf are investigated. Compared to pipe cracks, it was found that butt-fusion induced SCG can reduce the pipe tf > 60 %. Unlike longitudinal cracks, tf of external circumferential cracks, were found shorter than the internal ones, mandating an earlier evaluation. The new SCG model shows good accuracy with the experimental results. The same substitute geometry approach used can be followed for othercomplex designs, which aids in establishing a fundamental methodology for more realistic lifetime predictions.

The effect of temperature, pressure, and grind size on Total Dissolved Solids (TDS) and extraction yield of semi-automatic espresso machines

The number of coffee shops in Indonesia has grown from 1,083 stalls in 2016 to over 2,937 booths in 2019, representing a threefold growth. Coffee shop establishments must provide two essential kinds of equipment: espresso machines, which use pressure, and filter machines, which employ infusion. The issue lies in the exorbitant cost and immense power requirements of semi-automatic and automated espresso machines, which necessitate the use of a manual espresso machine for commercial operations. The equipment can generate satisfactory espresso but encounters several challenges; specifically, the espresso generated is characterized by inconsistency, constantly varying in quality. This might arise due to the erratic nature of the manufacturing process. The two objectives of this study are: (1) to design an economically efficient semi-automatic espresso machine capable of producing products that meet the international quality standards set by the Specialty Coffee Association (SCA standard) and (2) to investigate the impact of critical factors such as pressure, temperature, and grind size, on the consistent quality of the resulting coffee (measured by Total Dissolved Solids (TDS) and extraction yield (EXT)). The research employs the Research and Development (RD) methodology. The research findings indicate that the optimal levels of Total Dissolved Solids (TDS) and extraction yield (EXT) may be attained by using a pressure setting of 8 bars, a temperature of 90ºC, and a grind size of 3.2 on the scale. The technique for optimizing the response resulted in Total Dissolved Solids (TDS) levels of 10.03% and extraction yield (EXT) values of 19.56%. The results have been deemed acceptable based on the criteria set by the global standards of Specialty Coffee Association (SCA).

Perturbation-tuned triple spiral metamagnetism and tricritical point in kagome metal ErMn6Sn6

Kagome materials are of topical interest for their diverse quantum properties linked with correlated magnetism and topology. Here, we report anomalous hydrostatic pressure (p) effect on ErMn6Sn6 through isobaric and isothermal-isobaric magnetization measurements. Magnetic field (H) suppresses antiferromagnetic TN while simultaneously enhancing the ferrimagnetic TC by exhibiting dual metamagnetic transitions, arising from the triple-spiral-nature of Er and Mn spins. Counter-intuitively, pressure enhances both TC and TN with a growth rate of 74.4 K GPa−1 and 14.4 K GPa−1 respectively. Pressure unifies the dual metamagnetic transitions as illustrated through p-H phase diagrams at 140 and 200 K. Temperature-field-pressure (T-H, T-p) phase diagrams illustrate distinct field- and pressure-induced critical points at (Tcr = 246 K, Hcr = 23.3 kOe) and (Tcr = 435.8 K, pcr = 4.74 GPa) respectively. An unusual increase of magnetic entropy by pressure around Tcr and a putative pressure-induced tricritical point pave a unique way of tuning the magnetic properties of kagome magnets through simultaneous application of H and p.

A data-driven approach for deducing process parameter influences on N2O selectivity for the Ostwald process

Nitrous oxide (N2O) represents one of the key chemicals regarding climate change due to the high global warming potential and significant annual emissions. The largest industrial contribution results from the catalytic oxidation of ammonia to nitric acid, known as the Ostwald process. Successful efforts to reduce the emissions have been made for decades, but mainly focus on secondary and tertiary reduction. However, due to the severe process parameters, only a few publications were able to study the primary reduction – minimizing the formation in the first place – under industrial conditions. Here we present a laboratory setup with an extended range of parameters reflecting and exceeding industrial conditions, while allowing for reproducibility of over 99.9 %. The reactor was successfully employed for process parameter analysis and optimization via a data-driven approach through statistical analysis within design of experiments. Increasing preheating temperature by 200 °C and ammonia volume fraction by 4 % L/L decreased nitrous oxide selectivity by a factor of 2.7 and 3.1 respectively, while an increase in pressure from 2.5 to 4.3 bar promoted laughing gas formation by 38 %. Additionally, the volume flow has been found to be statically insignificant. Furthermore, for the first time the non-linear and interaction effects of all process parameters have been deduced. The interaction between pressure and ammonia concentration, as well as pressure and preheating temperature decreases nitrous oxide formation and can even reverse the primary effect of pressure. These findings pave a path for an alternative way of optimization of the Ostwald process alongside the more common kinetic-based optimizations.

40Ar diffusion in phlogopite: [formula omitted] atomistic calibration and implications for Ar–melt–solid kinetic interactions and ascent dynamics of mantle xenoliths and kimberlites

40Ar/39Ar ages of phlogopite from kimberlite-hosted mantle xenoliths are commonly older than the kimberlite eruption, despite the fact that argon is supposed not to be retained by phlogopite at temperatures above hydrothermally-derived Ar closure temperatures (<500°C). Combining Molecular Dynamics (MD) with Nudged Elastic Band (NEB) and Transition State Theory (TST), we investigate 40Ar−PVT (Pressure−Volume−Temperature) relationships in pristine, defect-free, phlogopite and show that 40Ar diffusivity is several orders of magnitude slower than existing estimates with a strong effect of pressure on diffusion rates and retention of 40Ar at mantle conditions. These results imply to fundamentally revise residence- and transit-time estimates based on Ar kinetics in phlogopite assuming simple diffusive relaxation during upwelling. When accounting for pressure, 40Ar retention trends in phlogopite predict substantially slower kimberlite ascent rates than documented by independent chronometers, indicating that 40Ar resetting during ascent in phlogopite does not result from simple decompression-driven diffusive relaxation. We argue that 40Ar remobilization probably involves secondary structural–textural modifications induced by reaction-driven recrystallization or rim overgrowth. These findings have far-reaching consequences in terms of argon isotopic mobility at mantle depths as well as for dating and tracing metasomatic events during crust−mantle interactions in the evolution of the subcontinental mantle.

Fatigue behavior of polymethyl methacrylate/acrylonitrile butadiene styrene blends including blend composition, stress ratio, frequency, and holding pressure effects

In engineering applications, polymer materials are expected to exhibit superior fatigue life and balanced mechanical properties as essential performance criteria. The blending method is an important alternative in improving the performance criteria of ABS polymer in service. Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), and Dynamic Mechanical Analysis (DMA) methods were used for characterization. The effects of the PMMA fraction on the mechanical and fatigue behavior of PMMA/ABS blends were investigated by tensile and fatigue tests. Also, the influence of blend composition, stress amplitudes, stress ratio, holding pressure, and loading frequency on fatigue life is considered. The study improved yield strength, tensile strength, and elongation at break values of blends compared to ABS. In addition, 115 % and 75 % improvements were achieved in fatigue cycles at high and low-stress amplitudes with blends, respectively, for tension/tension loading. Similar improvements were obtained for fully reverse loading at 218 %. Thus, it was determined that the PMMA/ABS blend exhibited superior fatigue life in both tension/tension and fully reverse loading situations. Finally, it has been understood that PMMA/ABS blends can be designed to have mechanical properties and fatigue life behavior that can meet different requirements in conditions for engineering applications.

Pressure induced impact on mechanical, electrical, optical, and thermal properties of Li4OX2 (X = Cl, Br and I): DFT study

We investigate the pressure effect on Li4OX2 (X = Cl, Br, and I) for the first time using DFT simulation. Li4OCl2 shows mechanical stability up to 8 GPa, whereas Li4OBr2 has stability up to 30 GPa pressure according to the Born stability criteria. In contrast, Li4Ol2 becomes unstable above 3.0 GPa pressure. Hence, anomalies were observed for Li4OX2 (X = Cl, Br, and I) solid electrolyte for elastic parameters, Cij under pressure study. The elastic moduli are isotropic in the xy plane, conversely, along the xz and yz plane anisotropic behavior is observed. There is a band gap that exists at zero temperature and pressure. The contribution at the fermi level mainly comes from the O 2p states. The highest reflectivity (∼98 %) was observed for Li4OCl2 at ∼ 17 eV in the IR-visible-UV region showing that this material under study may be considered as a potential coating material to avoid solar heating. The smaller value of the volume thermal expansion coefficient for Li4OCl2 indicates stronger atomic bonding exists, which was also observed from the elastic parameter analysis.

부모의 성취압력과 아동의 행복감의 관계에서 자아탄력성과 미디어 중독의 매개효과

The purpose of this study was to examine how parents' achievement pressure affects children's happiness, and to examine the mediating effects of children's ego resilience and media device addiction in the relationship between parents' achievement pressure and children's happiness. To this end, the data of 1,393 people from the 12th (2019) Korean Children's Panel data of the Childcare Policy Research Institute were used. For data analysis, Cronbach's α, frequency and percentage, average analysis, correlation analysis, multiple regression analysis, three-step regression analysis, and Sobel test were performed using the SPSS 26.0 program. As a result of the study, first, parental achievement pressure was a factor that negatively affected children's happiness, and the higher the level of parental achievement pressure, the lower the child's happiness. Second, it was found that there was a partial mediating effect of children's self-resilience in the effect of parents' achievement pressure on children's happiness. Third, it was found that there was a partial mediating effect of children's addiction to media devices in the effect of parents' achievement pressure on children's happiness. Through this study, it was found that parents' achievement pressure negatively affects children's happiness, and in this relationship, children's high self-resilience has a positive partial mediating effect on children's happiness, and children's high media addiction has a negative partial mediating effect on children's happiness. These results are significant in that they give implications for important variables to consider when planning programs to improve children's happiness in the future

A case report of Giant Lipoma involving shoulder Joint

Giant lipomas involving shoulder joints are rare. They cause symptoms due to their pressure effects and compression of surrounding structures. Surgical excision remains only definite treatment.

Studies the Effect of Particle Size, Binder Ratio and Pressure on Compaction Energy of Water Hyacinth Briquettes

Studies the Effect of Particle Size, Binder Ratio and Pressure on Compaction Energy of Water Hyacinth Briquettes

How institutional pressures on green innovation are perceived by firms? The role of board social ties

AbstractInstitutional pressures are major driving forces for firms' green innovation. However, there is significant heterogeneity in firms' responses to these forces due to the complex information environment within the institutional field. Social ties are known to provide information and resources. This study explores how board social ties, including business and political ties, shape firms' responsiveness to formal and informal institutional forces related to green innovation. Using a dataset from Chinese listed companies in the manufacturing sector, we propose that firms' business ties strengthen the effects of various institutional pressures on green innovation. On the other hand, political ties strengthen the impact of environmental regulation on green innovation but weaken the influence of imitative pressure on green innovation. This suggests that political ties can be a double‐edged sword in firms' responses to institutional pressures. This research contributes to institutional theory and social capital theory, offering implications for green innovation strategies.

Effects of dynamic injection pressures on spray, combustion, and exhaust emission characteristics in a CRDI diesel engine with naval vessel fuel

Effects of dynamic injection pressures on spray, combustion, and exhaust emission characteristics in a CRDI diesel engine with naval vessel fuel