Search results for: high pressure zone

Authors: Radhe Tado, Ashish B. Deoghare, K. M. Pandey

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The aim of this study is to estimate the effect of blood flow through the coronary artery in human heart so as to assess the coronary artery disease.Velocity, wall shear stress (WSS), strain rate and wall pressure distribution are some of the important hemodynamic parameters that are non-invasively assessed with computational fluid dynamics (CFD). These parameters are used to identify the mechanical factors responsible for the plaque progression and/or rupture in left coronary arteries (LCA) in coronary arteries.The initial step for CFD simulations was the construction of a geometrical model of the LCA. Patient specific artery model is constructed using computed tomography (CT) scan data with the help of MIMICS Research 19.0. For CFD analysis ANSYS FLUENT-14.5 is used.Hemodynamic parameters were quantified and flow patterns were visualized both in the absence and presence of coronary plaques. The wall pressure continuously decreased towards distal segments and showed pressure drops in stenotic segments. Areas of high WSS and high flow velocities were found adjacent to plaques deposition.

Keywords: angiography, computational fluid dynamics (CFD), time-average wall shear stress (TAWSS), wall pressure, wall shear stress (WSS)

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Authors: Rifa’ah Mahmudah Bulu’

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MRSA is an important nosocomial pathogen in the world. Therefore, the prevention and effort to control MRSA is still very important to conduct. One of the preventions of MRSA, which have been reported by several studies, is Cefriaxone and Ethanol Extract of Ant Plant. This research is an experimental test to determine the potency of MRSA’s anti-bacterial with Cefriaxone (30 μg) and Ethanol Extract of Ant Plant (13 mg/ml) based on inhibition zone on LAB (Lempeng Agar Biasa). The size of inhibition zone that is formed on Cefriaxone is adjusted with CSLI criteria, which ≥ 21 mm of inhibition zone is called sensitive; ≤13 mm is called resistance and between 14-20 mm is called intermediate. This research is conducted three times. Comparative test between Cefriaxone and Ethanol Extract of Ant Plant is analyzed by Maan Whitney’s statistic method. The Result of Cefriaxone anti-bacterial potency shows the variety of inhibition zone. Cefriaxone forms approximately 16,5-20 mm with average 18,22mm of inhibition zone that make Cefriaxone’s criteria to MRSA’s inhibition is intermediate. Anti-bacterial potency of Ethanol Extract of Ant Plant is about 0,5-2 mm with average 1,17 mm of inhibition zone that prove MRSA is sensitive to Ant Plant. The conclusion of this research shows that Cefriaxone is intermediate to MRSA’s inhibition, while MRSA is sensitive to Ethanol Extract of Ant Plant, which at the end; it creates different potency of anti-bacterial between Cefriaxone and Ethanol Extract of Ant Plant.

Keywords: MRSA, cefriaxone, ant plant, CSLI, mann whitney

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Authors: Mahmoud Hassanin, Roshan Thawale, Kiran Yelamati

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Background: During current practice, intraoperative regular endotracheal cuff pressure monitoring is not routine, despite the significant number of clinicians interested in checking it after intubation to ensure a good seal and adequate ventilation. Aims and objectives: to highlight that the current practice has no guidance related to regular intra-operative monitoring of the endotracheal tube cuff pressure, which can improve patient safety and post-operative experience. Methods: local department survey was done targeting anaesthetists' current practice, measuring their knowledge and problem awareness to improve patient satisfaction and change the current approach. Results: The participants were not using the manometer, despite their interest in ensuring that the cuff pressure was high enough and there was a proper seal. More than 50% of the participant don't know the ideal range of the endotracheal tube cuff pressure range, and 32% don't know whether it is available or not in the theatre. Despite the previous finding, 100% of the participants used different methods to ensure adequate cuff pressure. The collected data revealed that at least 26% of the participant confirmed that they had seen patients having post-intubation complications. Conclusion: There is an increasing importance placed on quality assurance. Clinical practice varies widely among practitioners, with the only consistency being the omission of cuff manometers during routine intra-operative management, despite their proven benefit and efficacy. Encourage the anaesthetists and ODPs to use cuff pressure manometers. The availability of portable pressure manometers can help to maintain safe cuff pressures in patients requiring endotracheal intubation.

Keywords: endotracheal cuff pressure, intra-operative monitoring, current practice, patient satisfaction

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Authors: Bhanu Pant, Sanjay H. Upadhyay

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Frequently, the upper stage of high-performance launch vehicles utilizes cryogenic tank-submerged pressurization gas bottles with high volume-to-weight efficiency to achieve a direct gain in the satellite payload. Titanium alloys, owing to their high specific strength coupled with excellent compatibility with various fluids, are the materials of choice for these applications. Amongst the Titanium alloys, there are two alloys suitable for cryogenic applications, namely Ti6Al4V-ELI and Ti5Al2.5Sn-ELI. The two-phase alpha-beta alloy Ti6Al4V-ELI is usable up to LOX temperature of 90K, while the single-phase alpha alloy Ti5Al2.5Sn-ELI can be used down to LHe temperature of 4 K. The high-pressure gas bottles submerged in the LH2 (20K) can store more amount of gas in as compared to those submerged in LOX (90K) bottles the same volume. Thus, the use of these alpha alloy gas bottles stored at 20K gives a distinct advantage with respect to the need for a lesser number of gas bottles to store the same amount of high-pressure gas, which in turn leads to a one-to-one advantage in the payload in the satellite. The cost advantage to the tune of 15000$/ kg of weight is saved in the upper stages, and, thereby, the satellite payload gain is expected by this change. However, the processing of alpha Ti5Al2.5Sn-ELI alloy gas bottles poses challenges due to the lower forgeability of the alloy and mode of qualification for the critical severe application environment. The present paper describes the processing and challenges/ solutions during the development of these advanced gas bottles for LH2 (20K) applications.

Keywords: titanium alloys, cryogenic gas bottles, alpha titanium alloy, alpha-beta titanium alloy

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Authors: Cam Minh Tri Tien, Richard Fenrich, Tristan Shelley, Nam Mai-Duy, Allan Malano, Xuesen Zeng

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Since additive manufacturing is a layer-by-layer deposition approach, good bonding quality between adjacent layers is critically important to achieve optimal mechanical performance, including applications in pressure vessels. The need to enhance the strength of printed products, especially in the build direction where layup gaps and voids exist between the printed layers, has garnered significant attention. The proposed research will focus on improving the current Fused Deposition Modelling (FDM) process to produce polymers reinforced with chopped fibers, utilizing a controlled heat zone to enhance the adhesion between printed layers. Energy will be applied to both printed and printing layers to improve the bonding strength between adjacent layers. Through the enhanced FDM process, the mechanical performance of composite parts will experience a substantial improvement, particularly in the build direction, as compared to current FDM methods. A combination of experimental, numerical, and analytical methods will be employed to demonstrate the enhanced performance of heat-controlled 3D printed parts.

Keywords: 3D Printing, pressure vessels, interlayer bonding, controlled heat

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Authors: Y. H. Hwang, J. Won, Y. S. Kang

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Supported ionic liquid membranes (SILMs) have attracted due to the negligible vapor pressure of ionic liquids (ILs) as well as the high gas selectivity for specific gases such as CO2 or olefin. 1-ethyl-3-methylimidazolium tricyanomethanide ([EMIM][TCM]), 1-butyl-3-methylimidazolium tricyanomethanide ([BMIM][TCM]), show high CO2 solubility, CO2 absorption, rapid CO2 absorption rate and negligible vapor pressure, SILMs using these ILs have been good candidates as CO2 separation membranes. However, SILM has to be operated at a low differential pressure to prevent the solvent from being expelled from the pores of supported membranes. In this paper, we improve the mechanical strength by forming ion gels which provide the stability while it retains the diffusion properties of the liquid stage which affects the gas separation properties. The ion gel was created by the addition of tri-block copolymer, poly(styrene-ethylene oxide-b-styrene) in RTIL. SILM using five different RTILs, are investigated with and without ion gels. The gas permeance were measured and the gas performance with and without the SEOS were investigated.

Keywords: ion gel, ionic liquid, membrane, nanostructure

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Authors: Saumya R. Jha, Krishanu Biswas, Nilesh P. Gurao

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Several recent investigations have revealed medium entropy alloys exhibiting better mechanical properties than their high entropy counterparts. This clearly establishes that although a higher entropy plays a vital role in stabilization of particular phase over complex intermetallic phases, configurational entropy is not the primary factor responsible for the high inherent strengthening in these systems. Above and beyond a high contribution from friction stresses and solid solution strengthening, strain hardening is an important contributor to the strengthening in these systems. In this regard, researchers have developed severe plastic deformation (SPD) techniques like High Pressure Torsion (HPT) to incorporate very high shear strain in the material, thereby leading to ultrafine grained (UFG) microstructures, which cause manifold increase in the strength. The presented work demonstrates a meticulous study of the variation in mechanical properties at different radial displacements from the center of HPT tested equiatomic ternary FeMnNi synthesized by casting route, which is a low stacking fault energy FCC alloy that shows significantly higher toughness than its high entropy counterparts like Cantor alloy. The gradient in grain sizes along the radial direction of these specimens has been modeled using microstructure entropy for predicting the mechanical properties, which has also been validated by indentation tests. The dislocation density is computed by FEM simulations for varying strains and validated by analyzing synchrotron diffraction data. Thus, the proposed model can be utilized to predict the strengthening behavior of similar systems deformed by HPT subjected to varying loading conditions.

Keywords: high pressure torsion, severe plastic deformation, configurational entropy, dislocation density, FEM simulation

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Authors: Bachir Chemani, Rachid Halfaoui

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The aim of study was to evaluate pressure distribution characteristics of the elastic textile bandages using two instrumental techniques: a prototype Instrument and a load Transference. The prototype instrument which simulates shape of real leg has pressure sensors which measure bandage pressure. Using this instrument, the results show that elastic textile bandages presents different pressure distribution characteristics and none produces a uniform distribution around lower limb. The load transference test procedure is used to determine whether a relationship exists between elastic textile bandage structure and pressure distribution characteristics. The test procedure assesses degree of load, directly transferred through a textile when loads series are applied to bandaging surface. A range of weave fabrics was produced using needle weaving machine and a sewing technique. A textile bandage was developed with optimal characteristics far superior pressure distribution than other bandages. From results, we find that theoretical pressure is not consistent exactly with practical pressure. It is important in this study to make a practical application for specialized nurses in order to verify the results and draw useful conclusions for predicting the use of this type of elastic band.

Keywords: textile, cotton, pressure, venous ulcers, elastic

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Authors: M. M. Ubayo, U. S. Babuga, A. Garba

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The study examined the level of climate change awareness and perception by rice farmers in Jigawa State, Nigeria. A multi-stage and purposive sampling technique was used to select respondents. The state is divided into four agricultural zones namely Birninkudu zone, Gumel zone, Hadejia zone, and Kazaure zone. Two agricultural zones (Gumel zone and Hadejia zones) were purposively selected. Six Local Government Areas (LGAs) were randomly selected from the two zones. Also, twenty rice farmers were purposively selected from each of the LGAS. Data were analyzed using frequency and percentages. The result shows that 83.3% of the respondents are aware of the climate change impact on their rice output. Personal experience is the main sources of climate change information in the study area, another 45.6% adopted use of irrigation as the most effective measure to combating climate change, 25.5% use of early maturing variety. Further studies are needed on how to combat the threat and menace of the climate change in the study area.

Keywords: awareness, perception, climate, change, Jigawa

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Authors: Mandob Enyegue Damaris, Oko Ndjollo Viviane

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The prevalence of Metabolic Syndrome is increasing throughout the world. The etiology of the metabolic syndrome is dependent on different factors such as ethnic group. This study aimed to evaluate the metabolic syndrome among Mbo ethnic group people leaving in Yaounde, Cameroon. The study conducted on the hundred and thirty two people 40 men and 92 women aged between 18-60 years who were referred to the Andre Fouda Medical Fundation in Yaounde. Metabolic syndrome was diagnosed using Adult Treatment Panel-III (A.T.P-III) 2001 guidelines. The mean of age, high fasting blood glucose, triglycerides levels and total cholesterol levels were significantly (P<0.05) higher in women with metabolic syndrome. High blood pressure level (56.80%), high fasting glucose (20.45%) and high waist circumference (10.60%) were respectively the most frequent characteristics in comparison to others metabolic components. The overall prevalence of MetS was (4.55%) and higher in women (3.03%) than in men (1.52%). The prevalence of MetS is low in originates of Mbo ethnic group of Yaounde. High blood pressure is the most common abnormality.

Keywords: individual components, metabolic syndrome, Mbo ethnic group, Yaounde-Cameroon

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Authors: Deepa Shokeen, Bani Tamber Aeri

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Non-communicable diseases in general and cardiovascular diseases (CVD) in particular are a big cause of concern worldwide especially in fast growing economy like India. CVD is one of the leading causes of deaths in India. Risk factors for cardiovascular disease are now significant in all populations. At least one-third of all CVD is attributable to five risk factors: tobacco use, alcohol use, high blood pressure, high cholesterol and obesity. Methods: This article aspires to collate data gathered by relevant studies conducted after year 2000 and provide an overview of the prevalence of CVD in India and worldwide. Results: Studies show an increased prevalence of cardiovascular risk factors in India as compared to other developing and developed countries with recent trends showing incidence in younger age group. It is seen to affect almost all sections of the society from young to old and most affluent to least affluent. High blood pressure, high cholesterol, tobacco and alcohol use, as well as low vegetable and fruit intake, already figure among the top risk factors. Conclusion: The prevalence of risk factors associated with CVD has increased and will keep on increasing in India as indicated by studies in the last decade and as predicted by the projections for future estimates. Some major risks are modifiable in that they can be prevented, treated, and controlled. There are considerable health benefits at all ages, for both men and women, in stopping smoking, reducing cholesterol and blood pressure, eating a healthy diet and increasing physical activity.

Keywords: prevalence, cardiovascular disease, India, risk factors

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Authors: Matthias Banholzer, Hagen Müller, Michael Pfitzner

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Gas internal combustion engines are widely used as propulsion systems or in power plants to generate heat and electricity. While there are different types of injection methods including the manifold port fuel injection and the direct injection, the latter has more potential to increase the specific power by avoiding air displacement in the intake and to reduce combustion anomalies such as backfire or pre-ignition. During the opening process of the injector, multiple flow regimes occur: subsonic, transonic and supersonic. To cover the wide range of Mach numbers a compressible pressure-based solver is used. While the standard Pressure Implicit with Splitting of Operators (PISO) method is used for the coupling between velocity and pressure, a high-resolution non-oscillatory central scheme established by Kurganov and Tadmor calculates the convective fluxes. A blending function based on the local Mach- and CFL-number switches between the compressible and incompressible regimes of the developed model. As the considered operating points are well above the critical state of the used fluids, the ideal gas assumption is not valid anymore. For the real gas thermodynamics, the models based on the Soave-Redlich-Kwong equation of state were implemented. The caloric properties are corrected using a departure formalism, for the viscosity and the thermal conductivity the empirical correlation of Chung is used. For the injector geometry, the dimensions of a diesel injector were adapted. Simulations were performed using different nozzle and needle geometries and opening curves. It can be clearly seen that there is a significant influence of all three parameters.

Keywords: high pressure gas injection, hybrid solver, hydrogen injection, needle opening process, real-gas thermodynamics

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Authors: Keshav Raj Acharya, Thakur Silwal, Neelam C. Poudyal

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Buffer zones, the peripheral areas around the national parks and wildlife reserves, are available for the purpose of benefitting the local inhabitants by providing forest products for subsistence needs of basic forest products outside the protected areas. The forest area within the buffer zone has been managed as a buffer zone community forest (BZCF) for the last 25 years after the approval of the buffer zone management regulation 1996. With a case study of select BZCF in Bardia National Park, this study aims to analyze whether the benefit provided by BZCF is equally available to poor users among other socioeconomic classes of the users. The findings are based on the analysis of cross-sectional data involving household surveys (n=305) and key informants’ interviews (n=10) as well as office records available at different 5 buffer zone community forest user groups offices. Results indicate that despite the provisions of subsidized rates for poor; poor households were more deprived due to higher forest products price particularly, the timber price in buffer zone. Evidence also indicate that due to the increased forest coverage, the incidence of wildlife damage has also increased and impacted the poor more due to lack of land ownership as well as limited alternatives. Clear community forest management guidelines with equitable benefit sharing and compensatory mechanisms to the users of poor socioeconomic class have been identified as a solution to increase the benefit to poor users in BZCFUGs.

Keywords: crop depredation, forest products, users, wellbeing ranking

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Authors: Karen Louise Lacey, Dario Javier Pavon Vargas, Massimiliano Rinaldi, Luca Cattani, Sara Rainieri

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The effects of high-pressure processing (HPP) and thermal treatments (TT) on quality markers of strawberry nectar (12 °Brix, 3,3 pH) was studied before and after treatments. TT and HPP treatments ensured a 3-log aerobic bacteria inactivation. No significant difference was detected in terms of pH and °Brix. TT samples were less red (a* less positive) than all HPP treated samples, while all samples were less red than the control. Apparent viscosity was significantly increased in all the HPP treatments, at 10 1/s shear rate, control was 79.04±7.94 mPa•s and the 600 MPa-20 min treatment were 327.10±1.64 mPa•s. This work suggests that HPP treatments may maintain the quality markers of strawberry nectar better.

Keywords: HPP, strawberry nectar, colour , viscosity

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Authors: Desmond Appiah, Fan Zhang, Shouqi Yuan, Wei Xueyuan, Stephen N. Asomani

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The side channel pump has distinctive hydraulic performance characteristics over other vane pumps because of its generation of high pressure heads in only one impeller revolution. Hence, there is soaring utilization and application in the fields of petrochemical, food processing fields, automotive and aerospace fuel pumping where high heads are required at low flows. The side channel pump is characterized by unstable flow because after fluid flows into the impeller passage, it moves into the side channel and comes back to the impeller again and then moves to the next circulation. Consequently, the flow leaves the side channel pump following a helical path. However, the pressure fluctuation exhibited in the flow greatly contributes to the unwanted noise and vibration which is associated with the flow. In this paper, a side channel pump prototype was examined thoroughly through numerical calculations based on SST k-ω turbulence model to ascertain the pressure fluctuation behavior. The pressure fluctuation intensity of the 3D unstable flow dynamics were carefully investigated under different working conditions 0.8QBEP, 1.0 QBEP and 1.2QBEP. The results showed that the pressure fluctuation distribution around the pressure side of the blade is greater than the suction side at the impeller and side channel interface (z=0) for all three operating conditions. Part-load condition 0.8QBEP recorded the highest pressure fluctuation distribution because of the high circulation velocity thus causing an intense exchanged flow between the impeller and side channel. Time and frequency domains spectra of the pressure fluctuation patterns in the impeller and the side channel were also analyzed under the best efficiency point value, QBEP using the solution from the numerical calculations. It was observed from the time-domain analysis that the pressure fluctuation characteristics in the impeller flow passage increased steadily until the flow reached the interrupter which separates low-pressure at the inflow from high pressure at the outflow. The pressure fluctuation amplitudes in the frequency domain spectrum at the different monitoring points depicted a gentle decreasing trend of the pressure amplitudes which was common among the operating conditions. The frequency domain also revealed that the main excitation frequencies occurred at 600Hz, 1200Hz, and 1800Hz and continued in the integers of the rotating shaft frequency. Also, the mass flow exchange plots indicated that the side channel pump is characterized with many vortex flows. Operating conditions 0.8QBEP, 1.0 QBEP depicted less and similar vortex flow while 1.2Q recorded many vortex flows around the inflow, middle and outflow regions. The results of the numerical calculations were finally verified experimentally. The performance characteristics curves from the simulated results showed that 0.8QBEP working condition recorded a head increase of 43.03% and efficiency decrease of 6.73% compared to 1.0QBEP. It can be concluded that for industrial applications where the high heads are mostly required, the side channel pump can be designed to operate at part-load conditions. This paper can serve as a source of information in order to optimize a reliable performance and widen the applications of the side channel pumps.

Keywords: exchanged flow, pressure fluctuation, numerical simulation, side channel pump

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Authors: Yeganeh Attari, Gudmund Reidar Eiksund, Hans Peter Jostad

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In Geotechnical practice, there is no standard method recognized by the industry to account for the reduction of safety factor of a slope as an effect of soil displacement and pore pressure build-up during pile installation. Pile driving disturbs causes large strains and generates excess pore pressures in a zone that can extend many diameters from the installed pile, resulting in a decrease of the shear strength of the surrounding soil. This phenomenon may cause slope failure. Moreover, dissipation of excess pore pressure set-up may cause weakening of areas outside the volume of soil remoulded during installation. Because of complex interactions between changes in mean stress and shearing, it is challenging to predict installation induced pore pressure response. Furthermore, it is a complex task to follow the rate and path of pore pressure dissipation in order to analyze slope stability. In cohesive soils it is necessary to implement soil models that account for strain softening in the analysis. In the literature, several cases of slope failure due to pile driving activities have been reported, for instance, a landslide in Gothenburg that resulted in a slope failure destroying more than thirty houses and Rigaud landslide in Quebec which resulted in loss of life. Up to now, several methods have been suggested to predict the effect of pile driving on total and effective stress, pore pressure changes and their effect on soil strength. However, this is still not well understood or agreed upon. In Norway, general approaches applied by geotechnical engineers for this problem are based on old empirical methods with little accurate theoretical background. While the limitations of such methods are discussed, this paper attempts to capture the reduction in the factor of safety of a slope during pile driving, using coupled Finite Element analysis and cavity expansion method. This is demonstrated by analyzing a case of slope failure due to pile driving in Norway.

Keywords: cavity expansion method, excess pore pressure, pile driving, slope failure

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Authors: Shinji Sato, M. M. A. Alam, Manabu Takao

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In recent, investigation of an unsteady flow inside the resonance tube have become a strongly motivated research field for their potential application as high-frequency actuators. By generating a shock wave inside the resonance tube, a high temperature and pressure can be achieved inside the tube, and this high temperature can also be used to ignite a jet engine. In the present research, a computational fluid dynamics (CFD) analysis was carried out to investigate the flow inside the resonance tube. The density-based solver of rhoCentralFoam in OpenFOAM was used to numerically simulate the flow. The supersonic jet that was driven by a cylindrical nozzle with a nominal exit diameter of φd = 20.3 mm impinged onto the resonance tube. The jet pressure ratio was varied between 2.6 and 7.8. The gap s between the nozzle exit and tube entrance was changed between 1.5d and 3.0d. The diameter and length of the tube were taken as D = 1.25d and L=3.0D, respectively. As a result, when a supersonic jet has impinged onto the resonance tube, a compression wave was found generating inside the tube and propagating towards the tube end wall. This wave train resulted in a rise in the end wall gas temperature and pressure. While, in an outflow phase, the gas near tube enwall was found cooling back isentropically to its initial temperature. Thus, the compression waves repeated a reciprocating motion in the tube like a piston, and a fluctuation in the end wall pressures and temperatures were observed. A significant change was found in the end wall pressures and temperatures with a change of jet flow conditions. In this study, the highest temperature was confirmed at a jet pressure ratio of 4.2 and a gap of s=2.0d

Keywords: compressible flow, OpenFOAM, oscillations, a resonance tube, shockwave

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Authors: Imane Benghalia, Mohammed Zamoum, Rachid Boucetta

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Hydrodynamic cavitation is a complex physical phenomenon that appears in hydraulic systems (pumps, turbines, valves, Venturi tubes, etc.) when the fluid pressure decreases below the saturated vapor pressure. The works carried out in this study aimed to get a better understanding of the cavitating flow phenomena. For this, we have numerically studied a cavitating bubbly flow through a Venturi nozzle. The cavitation model is selected and solved using a commercial computational fluid dynamics (CFD) code. The obtained results show the effect of the inlet pressure (10, 7, 5, and 2 bars) of the Venturi on pressure, the velocity of the fluid flow, and the vapor fraction. We found that the inlet pressure of the Venturi strongly affects the evolution of the pressure, velocity, and vapor fraction formation in the cavitating flow.

Keywords: cavitating flow, CFD, phase change, venturi

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Authors: Diana Gibson

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Aim: The first aim of the study was to ascertain the percentage of people who had been diagnosed with High Blood Pressure and/ or Type2 Diabetes Mellitus in Matzikama municipal district, Western Cape, South Africa. These two conditions are reportedly very high in this particular province, even though few statistics are available. A second aim was to gain insight into the understanding of these two conditions among sufferers. A third aim was to determine their allopathic use as well as indigenous medicinal plants to manage these conditions. A fourth aim was to understand how users of medicinal plants attend to their materiality and relationality as a continuum between humans and plants. The final aim was to ascertain the conservation status of medicinal plants utilised. Methods: One thousand one hundred and eighty-four (1184) respondents were interviewed. Semi-structured surveys were utilised to gather data on the percentage of people who had been medically diagnosed with High Blood Pressure and/or Type 2 Diabetes Mellitus. Local healers and knowledgeable old people were subsequently selected through a non-probability snowball sampling method. They were helped with plant collection. The plants were botanically identified. Results: The study found that people who have been diagnosed with High Blood Pressure or Type 2 Diabetes Mellitus drew on and continuously moved between biomedical and local understandings of these conditions. While they followed biomedical treatment regimens as far as possible they also drew on alternative ways of managing it through the use of medicinal plants. The most commonly used plant species overall were Lessertia frutescens, Tulbaghia violacea, Artemisia afra and Leonotus leonurus. For the users, medicinal plants were not mere material entities, they were actants in social networks where knowledge was produced through particular practices in specific places. None of the identified plants are currently threatened. Significance: Sufferers had a good understanding of the symptoms of and biomedical treatment regime for both conditions, but in everyday life they adhered to their local understandings and medicinal plants for treatment. The majority used reportedly used prescribed medication as well as plant alternatives.

Keywords: diabetes, high blood pressure, medicine, plants

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Authors: Loonibha Manandhar, Rajendra Bhandari, Kumud Raj Kafle

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Nepal’s Terai region is a part of the Ganges river basin which is one of the most disaster-prone areas of the world, with recurrent monsoon flooding causing millions in damage and the death and displacement of hundreds of people and households every year. The vulnerability of human settlements to natural disasters such as floods is increasing, and mapping changes in land use practices and hydro-geological parameters is essential in developing resilient communities and strong disaster management policies. The objective of this study was to develop a flood hazard zonation map of Orai Khola watershed and map the decadal land use/land cover dynamics of the watershed. The watershed area was delineated using SRTM DEM, and LANDSAT images were classified into five land use classes (forest, grassland, sediment and bare land, settlement area and cropland, and water body) using pixel-based semi-automated supervised maximum likelihood classification. Decadal changes in each class were then quantified using spatial modelling. Flood hazard mapping was performed by assigning weights to factors slope, rainfall distribution, distance from the river and land use/land cover on the basis of their estimated influence in causing flood hazard and performing weighed overlay analysis to identify areas that are highly vulnerable. The forest and grassland coverage increased by 11.53 km² (3.8%) and 1.43 km² (0.47%) from 1996 to 2016. The sediment and bare land areas decreased by 12.45 km² (4.12%) from 1996 to 2016 whereas settlement and cropland areas showed a consistent increase to 14.22 km² (4.7%). Waterbody coverage also increased to 0.3 km² (0.09%) from 1996-2016. 1.27% (3.65 km²) of total watershed area was categorized into very low hazard zone, 20.94% (60.31 km²) area into low hazard zone, 37.59% (108.3 km²) area into moderate hazard zone, 29.25% (84.27 km²) area into high hazard zone and 31 villages which comprised 10.95% (31.55 km²) were categorized into high hazard zone area.

Keywords: flood hazard, land use/land cover, Orai river, supervised maximum likelihood classification, weighed overlay analysis

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Authors: Richard Chen

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The study is mainly focused on the influence of different kinds of friendships on the well being of Chinese high school students. The main objective is to find out whether friendship style focusing on depth rather than breadth and whether making friends based on similarities in personality and character rather than interests and hobbies improve students’ mental state. Overall, 262 high school participants completed our study by filling out questionnaires online across China. Data showed, unexpectedly, optimal combinations of friendship styles indicate that students who seek depth of connection in friendship benefit more by focusing more on hobbies than on personalities, and those aiming to expand their social connections would be happier and less stressed when they made friends with those who shared their personalities rather than hobbies. The relationship between stress and the frequency of self-talk was also investigated, and a positive correlation between the pressure a student felt, and the frequency of self-talk behavior was confirmed. The results shed light on relationship management and wellbeing among Chinese high school students and may be applied by counselors and teachers to improve the overall level of satisfaction for Chinese high school students.

Keywords: hobbies, personalities, happiness, pressure, self-talk

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Authors: Branimir Jurun, Elza Jurun

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The focus of this paper is the description of an instrument called 'Quattuor 45' and defining of wave pressure measurement. Special attention is given to measurement of wave pressure created by the wind speed increasing obtained with the instrument 'Quattuor 45' in the investigated area. The study begins with respect to theoretical attitudes and numerous up to date investigations related to the waves approaching the coast. The detailed schematic view of the instrument is enriched with pictures from ground plan and side view. Horizontal stability of the instrument is achieved by mooring which relies on two concrete blocks. Vertical wave peak monitoring is ensured by one float above the instrument. The synthesis of horizontal stability and vertical wave peak monitoring allows to create a representative database for wave pressure measuring. Instrument ‘Quattuor 45' is named according to the way the database is received. Namely, the electronic part of the instrument consists of the main chip ‘Arduino', its memory, four load cells with the appropriate modules and the wind speed sensor 'Anemometers'. The 'Arduino' chip is programmed to store two data from each load cell and two data from the anemometer on SD card each second. The next part of the research is dedicated to data processing. All measured results are stored automatically in the database and after that detailed processing is carried out in the MS Excel. The result of the wave pressure measurement is synthesized by the unit of measurement kN/m². This paper also suggests a graphical presentation of the results by multi-line graph. The wave pressure is presented on the left vertical axis, while the wind speed is shown on the right vertical axis. The time of measurement is displayed on the horizontal axis. The paper proposes an algorithm for wind speed measurements showing the results for two characteristic winds in the Adriatic Sea, called 'Bura' and 'Jugo'. The first of them is the northern wind that reaches high speeds, causing low and extremely steep waves, where the pressure of the wave is relatively weak. On the other hand, the southern wind 'Jugo' has a lower speed than the northern wind, but due to its constant duration and constant speed maintenance, it causes extremely long and high waves that cause extremely high wave pressure.

Keywords: instrument, measuring unit, waves pressure metering, wind seed measurement

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Authors: John Hardy, Paul Lushenko

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he twenty-first century international security order has been fraught with challenges to the credibility and stability of the post-Cold War status quo. Although the American-led international system has rarely been threatened directly by dissatisfied states, an underlying challenge to the international security order has emerged in the form of a slow-burning abnegation of small but significant aspects of the status quo. Meanwhile, those security challenges which have threatened to destabilize order in the international system have not clearly belonged to the traditional notions of diplomacy and armed conflict. Instead, the main antagonists have been both states and non-state actors, the issues have crossed national and international boundaries, and contestation has occurred in a ‘gray zone’ between peace and war. Gray zone conflicts are not easily categorized as military operations, national security policies or political strategies, because they often include elements of diplomacy, military operations, and statecraft in complex combinations. This study applies three approaches to conceptualizing the gray zone in which many contemporary conflicts take place. The first approach frames gray zone conflicts as a form of coercive diplomacy, in which armed force is used to add credibility and commitment to political threats. The second approach frames gray zone conflicts as a form of discrete military operation, in which armed force is used sparingly and is limited to a specific issue. The third approach frames gray zones conflicts as a form of proxy war, in which armed force is used by or through third parties, rather than directly between belligerents. The study finds that each approach to conceptualizing the gray zone accounts for only a narrow range of issues which fall within the gap between traditional notions of peace and war. However, in combination, all three approaches are useful in explicating the gray zone and understanding the character of contemporary security challenges which defy simple categorization. These findings suggest that coercive diplomacy, discrete military operations, and proxy warfare provide three overlapping lenses for conceptualizing the gray zone and for understanding the gray zone conflicts which threaten international security in the early twenty-first century.

Keywords: gray zone, international security, military operations, national security, strategy

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Authors: Ravi Gujjula, Chinna Eranna, Narasimha Mangadoddy

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Hydrodynamic study of gas and solid flow in an internally circulating fluidized bed with draft tube is made in this paper using high speed camera and pressure probes for the laboratory ICFB test rig 3.0 m X 2.7 m column having a draft tube located in the center of ICFB. Experiments were conducted using different sized sand particles with varying particle size distribution. At each experimental run the standard pressure-flow curves for both draft tube and annular region beds measured and the same time downward particles velocity in the annular bed region were also measured. The effect of superficial gas velocity, static bed height (40, 50 & 60 cm) and the draft tube gap height (10.5 & 14.5 cm) on pressure drop profiles, solid circulation pattern, and gas bypassing dynamics for the ICFB investigated extensively. The mechanism of governing solid recirculation and the pressure losses in an ICFB has been eluded based on gas and solid dynamics obtained from the experimental data. 3D ICFB CFD simulation runs conducted and extracted data validated with ICFB experimental data.

Keywords: icfb, cfd, pressure drop, solids recirculation, bed height, draft tube

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Authors: Adriana Hernandez-Martinez, Edgar D. Ramon-Raygoza

Abstract:

Currently, there has been a great interest, during the last years, on graphene due to its lubricant properties on friction and antiwear processes. Likewise, fluorographene has also been gaining renown due to its excellent chemical and physical properties which have been mostly applied in the electronics industry. Nevertheless, its tribological properties haven’t been analyzed thoroughly. In this paper, fluorographene was examined as an extreme pressure additive and the nano lubricant made with a cutting fluid and fluorographene in the range of 0.01-0.5% wt, which proved to withstand 53.78% more pounds than the conventional product and 7.12% more than the nano lubricant with graphene in a range between 0.01-0.5% wt. Said extreme pressure test was carried out with a Pin and Vee Block Tribometer following an ASTM D3233A test. The fluorographene used has a low C/F ratio, which reflects a greater presence of atomic fluorine and its low oxygen percentage, supports the substitution of oxygen-containing groups by fluorine. XPS Spectra shows high atomic fluorine content of 56.12%, and SEM analysis details the formation of long and clear crystalline structures, in the fluorographene used.

Keywords: extreme pressure additive, fluorographene, nanofluids, nanolubricant

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Authors: Jean De Dieu Ayabagabo, Paul A.Onjoro, Karubiu P. Migwi, Marie C. Dusingize

Abstract:

This study investigated the effects of feed on milk yield and quality through feed monitoring and quality assessment, and the consequent enteric methane gas emissions from smallholder dairy farms in drier areas of Rwanda, using the Tier II approach for four seasons in three zones, namely; Mayaga and peripheral Bugesera (MPB), Eastern Savanna and Central Bugesera (ESCB), and Eastern plateau (EP). The study was carried out using 186 dairy cows with a mean live weight of 292 Kg in three communal cowsheds. The milk quality analysis was carried out on 418 samples. Methane emission was estimated using prediction equations. Data collected were subjected to ANOVA. The dry matter intake was lower (p<0.05) in the long dry season (7.24 Kg), with the ESCB zone having the highest value of 9.10 Kg, explained by the practice of crop-livestock integration agriculture in that zone. The Dry matter digestibility varied between seasons and zones, ranging from 52.5 to 56.4% for seasons and from 51.9 to 57.5% for zones. The daily protein supply was higher (p<0.05) in the long rain season with 969 g. The mean daily milk production of lactating cows was 5.6 L with a lower value (p<0.05) during the long dry season (4.76 L), and the MPB zone having the lowest value of 4.65 L. The yearly milk production per cow was 1179 L. The milk fat varied from 3.79 to 5.49% with a seasonal and zone variation. No variation was observed with milk protein. The seasonal daily methane emission varied from 150 g for the long dry season to 174 g for the long rain season (p<0.05). The rain season had the highest methane emission as it is associated with high forage intake. The mean emission factor was 59.4 Kg of methane/year. The present EFs were higher than the default IPPC value of 41 Kg from developing countries in African, the Middle East, and other tropical regions livestock EFs using Tier I approach due to the higher live weight in the current study. The methane emission per unit of milk production was lower in the EP zone (46.8 g/L) due to the feed efficiency observed in that zone. Farmers should use high-quality feeds to increase the milk yield and reduce the methane gas produced per unit of milk. For an accurate assessment of the methane produced from dairy farms, there is a need for the use of the Life Cycle Assessment approach that considers all the sources of emissions.

Keywords: footprint, forage, girinka, tier

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Authors: Pardeep Bishnoi, Mayank Srivastava, Mrityunjay Kumar Sinha

Abstract:

This article represents the numerical investigation of the pressure and velocity field variation of the dynamics of pendant drop formation through a capillary tube. Numerical simulations are executed using volume of fluid (VOF) method in the computational fluid dynamics (CFD). In this problem, Non Newtonian fluid is considered as dispersed fluid whereas air is considered as a continuous fluid. Pressure contours at various time steps expose that pressure varies nearly hydrostatically at each step of the dynamics of drop formation. A result also shows the pressure variation of the liquid droplet during free fall in the computational domain. The evacuation of the fluid from the necking region is also shown by the contour of the velocity field. The role of surface tension in the Pressure contour of the dynamics of drop formation is also studied.

Keywords: pressure contour, surface tension, volume of fluid, velocity field

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Authors: Makhlouf Mourad, Medkour Mihoub, Bouchher Omar, Messabih Sidi Mohamed, Benrachedi Khaled

Abstract:

This work is the modeling and simulation of fluid flow (liquid) through porous media. This type of flow occurs in many situations of interest in applied sciences and engineering, fluid (oil) consists of several individual substances in pure, single-phase flow is incompressible and isothermal. The porous medium is isotropic, homogeneous optionally, with the rectangular format and the flow is two-dimensional. Modeling of hydrodynamic phenomena incorporates Darcy's law and the equation of mass conservation. Correlations are used to model the density and viscosity of the fluid. A finite volume code is used in the discretization of differential equations. The nonlinearity is treated by Newton's method with relaxation coefficient. The results of the simulation of the pressure and the mobility of liquid flowing through porous media are presented, analyzed, and illustrated.

Keywords: Darcy equation, middle porous, continuity equation, Peng Robinson equation, mobility

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Authors: Moiz S. Vohra, Nagalingam Arun Prasanth, Wei L. Tan, S. H. Yeo

Abstract:

The understanding of generation and collapse of acoustic cavitation bubbles are prerequisites for application of cavitation erosion. Microbubbles generated due to rapid fluctuation of pressure induced by propagation of ultrasonic wave lead to formation of high velocity microjets and or shock waves upon collapse. Due to vast application of ultrasonic, it is important to characterize and understand cavitation collapse pressure under the radiating surface at different conditions. A comparative investigation is carried out to determine impact load and dynamic pressure distribution exerted upon bubble collapse using thin film pressure sensors. Measurements were recorded at different input conditions such as amplitude, stand-off distance, insertion depth of the horn inside the liquid and pulse on-off time of acoustic vibrations. Impact force of 2.97 N is recorded at amplitude of 108 μm and stand-off distance of 1 mm from the sensor film, whereas impulsive force as low as 0.4 N is recorded at amplitude of 12 μm and stand-off distance of 5 mm from the sensor film. The results drawn from the investigation indicated that variety of impact loads can be achieved by controlling generation and collapse of bubbles, making it suitable to use for numerous application.

Keywords: ultrasonic cavitation, bubble collapse, pressure mapping sensor, impact load

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Authors: Antanas Žiliukas, Mindaugas Kukis

Abstract:

The work deals with cellular pressure vessels subjected to internal pressure. Their cellular insert can be used for placing liquids or gases, which is necessary to carry out technological processes, and the vessel itself has a good bearing capacity. Numerical calculations of the three core structures, which measure the influence of the inner cylinder thickness on maximum bearing capacity are presented. The calculations are compared using strength criteria and they show the different strength safety level.

Keywords: pressure, strength criterion, sandwich plate, cellular vessel

Procedia PDF Downloads 287