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In this paper, we examine a steady laminar flow for an incompressible fluid located in a semi porous annular pipe and subjected to a favorable constant pressure gradient applied between the two borders of the pipe. The inner wall is impermeable and the fluid is sucked or injected at the outer wall at constant and uniform velocity, orthogonally to the wall. The problem under study depends on three parameters: the pipe gap ratio, the dimensionless external pressure gradient, and the Reynolds number defined from the sum of the suction or injection velocity and the maximum Hagen–Poiseuille velocity. The conservation of mass induces the zero-divergence velocity field which allows replacing the steady-flow Navier–Stokes equations with a single equation satisfied by the stream function and called the vorticity equation. Assuming the similarity-solution hypothesis, the problem under consideration is reduced to a fourth-order nonlinear ordinary differential equation with two boundary conditions at each wall. The numerical shooting technique including the Runge–Kutta algorithm and the Newton–Raphson optimization method is applied to obtain the solution for the steady flow. For various values of the dimensionless external pressure gradient, the profiles of the velocity components are found and investigations on the wall shear stress for both walls are performed. The results obtained are discussed and physical understandings for the problem studied are derived.

Researchers are under constant pressure to publish high-quality research. What, however, constitutes high-quality research? Most universities use accepted lists of top-tier journals, citation counts, or other metrics to assess the value of research contributions. We first explore the metrics by which research contributions are evaluated. These metrics provide at least some indication of the impact and value of an academic's stream of research.We then consider the issue of value beyond the commonly accepted metrics of article counts and citations. Should high-quality research create value for students and, especially in the case of business academics, for managers and practitioners? If so, rather than focusing exclusively on theoretical contributions, researchers should demonstrate the value-in-use of the research stream to the broader community. We present a set of conditions to support a research stream that delivers value-in-use to students and practitioners.We then turn to whether high-quality research implies finding solutions to societal challenges and problems. This would require a rethinking of the traditional views on the university's relationship with society at large. We explore issues of research concerning its contribution to society. We conclude by distilling these issues into several pieces of advice to new and mid-career academics regarding strategies and challenges in developing high-quality research.

The occurrence of bedsores in Ghanaian hospitals, elderly homes or care homes is especially high among patients or people who are incapacitated and cannot move or turn on their own, and who happen to remain in a particular posture for a very long time. Patients in coma, those operated on and for that matter in critical state, and patients confined to wheelchairs are primary examples. Constant pressure on some parts of the body leads to the occurrence of pressure sores or ulcers. This paper seeks to implement a Bedsore Easing System (BeSoSys) that integrate several embedded hardware components, a database and software to reduce the occurrence of bedsores. These embedded hardware components include the Bed Device Unit (BDU), the Pocket Device Unit (PDU), a pressure or weight sensor, a temperature sensor, and an inflation-deflation device. The BDU is fitted into the bed of the patient or on the surface of skin contact of the patient. The PDU is assigned to nurses or caretakers to serve as an alarm system for patient repositioning depending on situation. All activities in the Bedsore Easing System are logged into a database for future references. A bedridden patient exerts constant pressure on the bony protrusions of the body, and this causes bedsores. It was found out during the research that in Ghana, the nurses or caretakers used to turn and massage patients at some random time intervals as a way of preventing bedsores. This traditional way of turning and massaging patients is not only tedious but also ineffective. This paper seeks to provide easy, better, and effective solution to ease bedsores. The BeSoSys intends to prevent the occurrence of bedsores hence the alleviation of bedsore complications

Typically, unit discharge of slowly adapting receptors (SARs) declines slowly when lung inflation pressure is constant, although in some units it increases instead—a phenomenon hereinafter referred to as creeping. These studies characterize creeping behavior observed in 62 of 137 SAR units examined in anesthetized, open-chest, and mechanically ventilated rabbits. SAR units recorded from the cervical vagus nerve were studied during 4 s of constant lung inflation at 10, 20, and 30 cmH2O. Affected SAR units creep more quickly as inflation pressure increases. SAR units also often deactivate after creeping, i.e., their activity decreases or stops completely. Creeping likely results from encoder switching from a low discharge to a high discharge SAR, because it disappears in SAR units with multiple receptive fields after blocking a high discharge encoder in one field leaves low discharge encoders intact. The results support that encoder switching is a common mechanism operating in lung mechanosensory units.

In the event of a pandemic, the priorities for any commander must be focused on protecting their own personnel, maintaining combat capability and carrying out the missions. The personnel protection measures are implemented in a unitary and gradual conception depending on the pandemic evolution in the area of responsibility. The appearance of increasingly contagious viruses and the promotion of their rapid spread globally through the diversity and complexity of land, air and naval transport, forces us to reconsider our position on the following issues: training and recruitment of staff; making stocks; adaptation of protection measures, in particular of personnel; optimization of operating procedures based on clearly defined principles. Keywords: military centers; planning; personnel protection; protection measures; circuits; risk areas.

The present work introduces a numerical investigation of steam ejector optimum performance at constant pressure ratio used in many applications. The present study aims to maximize the ejector efficiency by optimizing the ejector mass ratio. The effect of geometrical parameters on ejector mass ratio and its efficiency is investigated at constant operating conditions. These parameters are the ejector convergent section angle, the constant area mixing chamber length and the angle of the ejector divergent section. The results showed that the ejector wall static pressure distributions were greatly affected by the investigated geometrical parameters. Furthermore, In order to avoid separation, the ejector divergent section angle must be selected carefully together with the operating conditions. The ejector mass ratio and efficiency increased with increasing the previously stated three geometrical parameters to gain their upper limit values, subsequent to that, the efficiency and mass ratio decreased with increasing these geometrical parameters. Moreover, there are certain optimum ejector convergent, divergent angles and the constant area mixing chamber length in order to optimize the ejector mass ratio and consequently its efficiency at given constant operating condition.

The effect of barothermal (HPHT) treatment on the structure and properties of carbides of refractory metals and their alloys is considered. The principal directions of studies are determined. The comparative analysis of data measured in studying the mechanical properties of WC–Co hard alloys after sintering at high pressures and temperatures is performed. It has been established that the crucial role in the formation of the structure and mechanical properties of WC–Co alloys in the process of HPHT treatment is played by the process temperature under constant pressure conditions.

To control the roof during gob-side entry retaining by roof cutting in inclined coal seams, the retained gob-side roadway is zoned based on the mechanical principle and technological process of no-pillar mining with gob-entry retention. A simplified mechanical model for surrounding rocks in different subzones was established by using theoretical analysis and numerical simulation to attain the demand for the support resistance and deformation of the roof in different subzones. According to load and deformation characteristics of the roof and mechanical characteristics of NPR cables, single props, and a sliding-type gangue-retaining structure formed by U-shaped steel inserts, the supporting systems for roadways in different subzones and the constitutive model thereof were established. On this basis, the action of the supporting system was analysed and a field test was performed. The results show that the supporting system undergoes three stages of behaviour, i.e., pressure growth, yielding under constant pressure, and stabilisation during whole entry retention. It can guarantee the collaborative deformation of the supporting systems with the roof on the premise of constant support resistance, thus satisfying the requirement for roadway protection. The roadway 150 m back from the working face is stable, and the final convergence between the roof and floor of the retained entry is 257 mm, showing a favourable entry-retention effect.

One of the renewable energy sources that can be used for electricity generation is the Pelton turbine. The purpose of this study was to determine the effect of the number of blades on the efficiency of a Pelton turbine with constant pressure. This research was conducted at the Unihaz mechanical engineering laboratory by varying the number of blades, namely 9 blade turbines and 12 blades. Tests were carried out by giving load gradually to the turbine until the turbine rotor rotation stopped rotating. The results show that in the turbine test with blades 9 the maximum rotation achieved is 698.2 rpm and the maximum rotor rotation is 714.5 rpm at blade 12. Likewise, the torque coefficient and power coefficient achieved by the turbine with 12 are greater when compared to the 9 blades. Meanwhile, the efficiency that can be achieved by turbines with 9 blades is 71% and at 12 blades is 79%. From this it can be concluded that the number of blades affects the rotation, torque coefficient, power coefficient and efficiency of the Pelton turbine with constant pressure.

The effect of employing four different reactor models, Zeldovich–von Neumann–Doring (ZND), constant volume (CV), constant pressure (CP), and the Shock routine from Chemkin, to perform detonation-relevant chemical modeling was assessed. The simulation results were compared in terms of characteristic length scales and chemical analyses with four representative mixtures: $$\hbox {H}_{2}{-}\hbox {O}_{2}{-}\hbox {N}_{2}$$ , $$\hbox {H}_{2}{-}\hbox {NO}_{2}/{\hbox {N}_{2}}{\hbox {O}_{4}}$$ , $${\hbox {C}_{3}}{\hbox {H}_{8}}{-}\hbox {O}_{2}{-}\hbox {N}_{2}$$ , and dimethyl ether (DME)– $$\hbox {O}_{2}{-}\hbox {CO}_{2}$$ . The following conclusions were drawn: (i) CV and CP reactor models shorten the induction zone length and strengthen the energy release rate in most mixtures. In terms of chemical kinetics, the impact of CP and CV reactor models is quite limited for $$\hbox {H}_{2}{-}\hbox {O}_{2}{-}\hbox {N}_{2}$$ and $$\hbox {H}_{2}{-}\hbox {NO}_{2}/{\hbox {N}_{2}}{\hbox {O}_{4}}$$ mixtures. However, the C2 branch is enhanced in CV and CP reactor models for $${\hbox {C}_{3}}{\hbox {H}_{8}}{-}\hbox {O}_{2}{-}\hbox {N}_{2}$$ mixture. Moreover, both reactor models weaken the intermediate-temperature chemistry and promote the high-temperature chemistry for DME– $$\hbox {O}_{2}{-}\hbox {CO}_{2}$$ mixtures; (ii) the Shock module can be employed to perform detonation modeling, as it provided similar results to the ZND simulations for all investigated mixtures; and (iii) the ZND reactor model is preferred over the zero-dimensional reactor models, while the Shock module of ANSYS is equivalent to the ZND reactor.

A large-capacity hydrogen storage system, which is also able to purify the hydrogen during storage, is appealing and bears significance for the mobile hydrogen use systems which require highly pure...

Firms are under constant pressure to minimize negative externalities and increase positive externalities. These pressures are translating into the corporate social responsibility (CSR) activities by firms. CSR is emerging as a widespread business activity, and firms are undertaking CSR voluntarily. This case provides a brief discussion of the scenario of CSR in India. It goes on to discuss the educational activities undertaken by firms under their CSR programmes. Brillio Technologies is one such company that has adopted CSR voluntarily, from the very first year of operations, in 2015. CSR actions of Brillio go beyond the legal requirements as it achieved remarkable results in community engagement and employee engagement. CSR activities of companies are internal to the organization, such as reducing and recycling waste, or external to the organization, such as reducing its carbon footprint. While Brillio undertook numerous internal activities, its focus was on external activities through its flagship programme ‘Bringing Smiles’. The programme successfully reached 100,000 underserved students through STEM education by 2020—the company partnered with NGOs and schools to achieve its social goals. Participants need to evaluate the existing programme and strategize for achieving the goals. They are posed with three choices: (a) increase employee volunteering hours, (b) partner with more NGOs and (c) recommend a foundation for taking up CSR activities. These strategies could be a huge drain on the resources, hence there is need for a cost-benefit analysis of the alternatives.

This work is focused on a quantitative procedure for estimating the generally unfavourable effects that incorrectly drilled holes, characterized by the initial clearance between a rivet and a hole, have on the fatigue life of riveted joints. The solution is based on an analytical approach using the stress-severity-factor concept. An experimental programme with riveted-joint specimens characterized by low-load transfer factors was realized in the Czech Aerospace Research Centre (VZLU) test lab under constant amplitude loading. The holes for rivet joints with 4-mm diameters were prepared with the clearance in a range of 0.0–0.16 mm. Force-controlled riveting was applied using a constant pressure force to form the driven head. To prevent fretting events between the joined parts, their anodized contact surfaces were lubricated with MOLYKA, plastic grease with molybdenum disulphide and graphite. The experimental data showed that the load-transfer factor and the fatigue life depend on the initial clearance between a rivet and a hole. The presented procedure introduced the hole-filling factor, integrated in the stress-severity-factor concept as a function of the initial clearance between a rivet and a hole.

The preservation of foods at low temperatures is a well-established concept. While conventional methods of food freezing rely on the isobaric (constant pressure) approach, they often result in a series of irreversible changes that can significantly hamper the quality of frozen foods. In recent years, taking its roots from the biomedical industry, isochoric (constant volume) freezing is gaining both research and commercial interest as an effective method of food preservation. The focus of this review is to present the state of the art of isochoric freezing of foods, highlighting the underlying mechanisms that make it unique, and understanding its impact on food quality, considering reports published in the past decade. An exclusive section is dedicated to its non-food applications, and this work also provides insights into the costs and economics of the process. Importantly, as this is an emerging area, the review concludes by highlighting the challenges and provides perspectives on the directions for future research.

The distinctions of dendritic morphology and sidebranching behavior when solidified under atmosphere pressure, constant pressure which is higher than atmosphere pressure (hereinafter referred to as constant pressure) and periodic pressure were investigated using 3-D phase field method. When growing at atmosphere pressure, side branches (secondary dendritic arms) are irregular. When solidified under constant pressure with a relatively high value, side branches are much more luxuriant, with more developed high-order side branches. When applied with periodic pressure, resonant sidebranching happens, leading to many more regular side branches and the smallest secondary dendritic arm spacing (SDAS) in the three cases. The significant difference in dendritic morphology is associated with tip velocity modulated by total undercooling including pressure and temperature undercooling. In the case of constant pressure, tip velocity increases linearly with total undercooling, and it varies periodically in periodic pressure case. The different variation trend in tip velocity is the reason for the distinct dendrite growth behavior in different cases. Unlike the phenomenon in constant pressure case where the dendrite grows faster with higher pressure, the dendrite grows slower under periodic pressure with higher amplitude, resulting in less developed primary dendrite and side branches. This is influenced by tip remelting due to low undercooling or even negative undercooling. It is revealed that the accelerated velocity of tip remelting increases with the decline of undercooling. The greater the amplitude of periodic pressure, the faster the tip remelting velocity during one period. This is the reason why the average tip velocity decreases with the rise of amplitude of periodic pressure.

The best recognized and also the most widespread example of tissue necrosis is bedsore. A bedsore is localized damage to the skin and other underlying tissue, usually over a bony prominence, as a result of prolonged, unrelieved pressure. The cause of bedsore is shearing forces; friction, moisture, and constant pressure contribute to the development of bedsore. Hospital research shows that bedsores develop from 3% to 4.5% of patients during prolonged hospitalization and Sores develop from 25% to 85% of patients with spinal cord injury. The doctor and nurses will regularly examine the patient who is at risk of developing bedsore and inspect each pressure sites at least twice a day. Doctors and nurses are important warriors who manage bedsore treatment effectively. This review describes the new strategies have been used to prevent and management of bedsore such as inexpensive foam devices, anti-pressure devices, air-filled equipment, a sheet of hydrogels, wound vacuum-assisted closer, skin bioprinting, and Lab VIEW virtual instrument.

This paper studies the problem of the constant pressure control for high pressure tubing. The main factors affecting the pressure change in high pressure oil pipe are the opening time of check valv...

Net importing countries are very susceptible to changes in the value of their currency. Pakistan, being a small open economy, faces a constant pressure in its current account and BOP, which leads to unavoidable stress on its exchange rate. Exchange rate movements affect the cost of imports directly which have been studied extensively in empirical literature. However, these studies ignore the possibility of asymmetric effects of exchange rate and its impact on import demand in Pakistan. An appreciation in exchange rate may have a different impact on demand for imports than depreciations depending upon the level of rigidity in consumer preferences as well as the availability of substitutes for consumer goods, capital goods and raw materials. We use quarterly data of Pakistan’s consumer goods, capital goods and raw material imports from 2005:Q1 to 2018:Q4 and employ a relatively recent econometric methodology, namely, Nonlinear Autoregressive Distributed Lag (NARDL) technique. The results confirm the existence of asymmetric impact of exchange rate in the long-run. The appreciation of currency has more pronounced impact in increasing imports relative to the depreciation of it in decreasing imports. There are further differences of this effect within imports across consumer goods, capital goods and raw materials. We present policy implications of this asymmetric effect of exchange rate on disaggregated consumer imports.

The oral environment is highly altered when a removable dental prosthesis is inserted. This further causes adverse effects on the integrity of the oral tissues. A rough surface on a denture may cause mechanical irritation resulting in a mucosal reaction, surface irregularities or porosities may result in accumulation of microbial plaque on the dentures, sometimes the constituents of the dental materials itself may induce an allergic reaction. A constant pressure on the bony ridge results in residual ridge resorption. Wearing complete denture significantly alter the masticatory function, indirectly resulting in nutritional deficiency. The sequelae of wearing complete denture reaction may be a direct or an indirect one. Keywords: Mucosal reaction, Mechanical irritation, Resorption, Sequelae.

For the first time, the solubility of β-carotene in pure and ethanol-modified subcritical water (SW) using the static method was determined. The experimental runs were performed at a temperature ranging from 298.15 to 403.15 K and 0–10% (w/w) of ethanol as a modifier at a constant pressure of 5 MPa. Samples were analyzed by UV–vis spectrophotometer. The solubility of β-carotene was found to range from 1.084 × 10−8 to 227.1 × 10−8 mol fractions in the subcritical water in above mentioned conditions. The obtained β-carotene solubility data were correlated using the linear model and modified Apelblat model. The obtained results showed the modified Apelblat model was better for estimating the solubility of β-carotene in SW. The values of the root-mean-square deviation (RMSD) between experimental and correlated data were calculated and used as the index of validity and accuracy for the model. Also, thermodynamic properties of the solution such as the Gibbs free energy of solution, enthalpy, and entropy of solution were estimated.

In the article we consider the flow of viscous compressible fluid in a channel with oscillating walls. The obtained solutions of linearized Navier–Stokes equations suggest that resonance phenomena are possible under certain conditions, namely, under the particular relation between the frequency of wall vibration, the geometrical characteristics of a channel and speed of sound in the fluid. Resonance phenomena result in the periodical changes of flow parameters with maximum amplitude. The numerical simulations based on full Navier–Stokes equations show that great increase in the mass rate of the flow can occur even if fluid is pumped at constant pressure gradient.

This work presents and validates a new methodology that determines the adiabatic ignition delay of a hydrocarbon-based fuel using several non-adiabatic ignition delay measurements. The new methodol...

In this paper, the unsteady MHD Couette flow through a porous medium of a viscous incompressible fluid bounded by two parallel porous plates under the influence of thermal radiation and chemical reaction is investigated. A uniform suction and injection are applied perpendicular to the plates while the fluid motion is subjected to the constant pressure gradient. The transformed conservation equations are solved analytically subject to physically appropriate boundary conditions by using the Eigenfunction expansion technique. The influence of some emerging non-dimensional parameters namely, pressure gradient, suction parameter, radiation parameter, and Hartman number are examined in detail. It is observed that the primary velocity is increased with increasing pressure gradient while the increase in radiation parameter leads to adecrease in the thermal profile of the flow.

Amióta a főiskolai, egyetemi szakzáró dolgozatokat és a doktori disszertációkat kitalálták, az ezek születése körüli szakmai bábáskodás szinte külön mesterséggé nőtte ki magát. Nem feltétlenül könnyű folyamatos és színvonalas kutatómunkára és írásra motiválni és szellemileg inspirálni a hallgatókat, különösen a növekvő tudományos elvárások és a határidők állandó szorításában. A szerző e téren szerzett tizenkét éves konzulensi és témavezetői tapasztalatairól, a tudományos írás műhelytitkairól, az ott alkalmazható technikákról és e munka néhány szép eredményéről szól ez a rövid tanulmány.

We analyze numerical methods for the determination of the adiabatic compressibility of fluids in computer experiments. Some of them like the Monte-Carlo (MC) method in constant pressure ensembles c...

International audience; This work is related to the determination of the local thermodynamic equilibrium (LTE) data of 90.5% air and 9.5% CH 4 mixture. The results of chemical composition, thermodynamic properties and transport coefficients are presented for temperatures (300 K to 30 kK) and pressure (1 and 10 bars) or mass density (0.1481 and 1.111 kg.m −3). The chemical composition is determined using the mass action law. Input data come from the NIST and JANAF sites. For pressure equation, Debye-Huckel's first order and virial's second order corrections are used in the equation system to take into account the different particle interactions. For the considered mixture (90.5% air and 9.5% CH 4) the properties are compared to those of pure air.

Copyright law is under constant pressure to evolve. Since the Copyright Act of 1790, which protected only maps, charts and books from unauthorized copying, 1 the law has grown to cover dramatic and...

Following a patented solution, a seat which is possible to change its stiffness was created. The seat contains an actively controlled pneumatic spring element (the PSE). For the requirement of working faster and more precisely, an improvement was applied. This article deals with derivation of mathematical model of the improved PSE system used for subsequent analysis. The model is considered as a mixed model which is a combination of single-discipline subsystems as mechanical, electrical, fluid and control ones. The simulations are carried out for varied input parameters and both the system parameters and system characteristics are calculated. The results describe the behavior of the improved system in two modes of controller setup: constant pressure and constant stiffness under static and dynamic conditions