Search results for: raised intraocular pressure
3831 The Determination of Sodium/Potassium Ion Ratio in Selected Edible Leafy Vegetables in North-Eastern Nigeria
Authors: Raymond D. Uzoh, Philip K. Shallsuku, Christopher S. Vaachia
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Selected edible leafy vegetables from North-eastern Nigeria were analysed for their sodium and potassium content in mg/100 g and the ratio Na+/K+ worked out. From experimental results, Venonia amydalina (bitter leaf) contained 150 mg (0.15 g) of sodium and 20500 mg (20.5 g) potassium with a ratio of 0.007, Brassica oleracea var capitata (cabbage) contained 300 mg (0.3 g) of sodium and 19000 mg (19 g) of potassium with a ration of 0.012. Others are Telfairia occidentalis (fluted pumpkin) with 400 mg (0.45 g) of sodium and 19500 mg (19.5 g) of potassium with a ratio of 0.020; Hibiscus sabdriffa (sorrel) has 200 mg (0.2 g) of sodium and 600 mg (0.6 g) of potassium with a ratio of 0.300; and Amarantus caudatus (spinach) contained 450 mg (0.45 g) of sodium and 23000 mg (23 g) of potassium with a ratio of 0.020. The presence of sodium and potassium in foods has become increasingly important as recent studies and dietary information gathered in this research has shown that sodium intake is not the sole consideration in elevated blood pressure but its considered as a ratio Na+/K+ fixed at 0.6. This ratio has been found to be a more important factor, suggesting that our diet should contain 67 % more potassium than sodium.Keywords: vegetables, sodium, potassium, blood pressure, diet, foods
Procedia PDF Downloads 4683830 Optimizing 3D Shape Parameters of Sports Bra Pads in Motion by Finite Element Dynamic Modelling with Inverse Problem Solution
Authors: Jiazhen Chen, Yue Sun, Joanne Yip, Kit-Lun Yick
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The design of sports bras poses a considerable challenge due to the difficulty in accurately predicting the wearing result after computer-aided design (CAD). It needs repeated physical try-on or virtual try-on to obtain a comfortable pressure range during motion. Specifically, in the context of running, the exact support area and force exerted on the breasts remain unclear. Consequently, obtaining an effective method to design the sports bra pads shape becomes particularly challenging. This predicament hinders the successful creation and production of sports bras that cater to women's health needs. The purpose of this study is to propose an effective method to obtain the 3D shape of sports bra pads and to understand the relationship between the supporting force and the 3D shape parameters of the pads. Firstly, the static 3D shape of the sports bra pad and human motion data (Running) are obtained by using the 3D scanner and advanced 4D scanning technology. The 3D shape of the sports bra pad is parameterised and simplified by Free-form Deformation (FFD). Then the sub-models of sports bra and human body are constructed by segmenting and meshing them with MSC Apex software. The material coefficient of sports bras is obtained by material testing. The Marc software is then utilised to establish a dynamic contact model between the human breast and the sports bra pad. To realise the reverse design of the sports bra pad, this contact model serves as a forward model for calculating the inverse problem. Based on the forward contact model, the inverse problem of the 3D shape parameters of the sports bra pad with the target bra-wearing pressure range as the boundary condition is solved. Finally, the credibility and accuracy of the simulation are validated by comparing the experimental results with the simulations by the FE model on the pressure distribution. On the one hand, this research allows for a more accurate understanding of the support area and force distribution on the breasts during running. On the other hand, this study can contribute to the customization of sports bra pads for different individuals. It can help to obtain sports bra pads with comfortable dynamic pressure.Keywords: sports bra design, breast motion, running, inverse problem, finite element dynamic model
Procedia PDF Downloads 483829 Clinical and Etiological Particularities of Infectious Uveitis in HIV+ and HIV- Patients in the Internal Medicine Department
Authors: N. Jait, M. Maamar, H. Khibri, H. Harmouche, N. Mouatssim, W. Ammouri, Z. Tazimezaelek, M. Adnaoui
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Introduction: Uveitis presents with inflammation of the uvea, intraocular, of heterogeneous etiology and presentation. The objective of our study is to describe the clinical and therapeutic characteristics of infectious uveitis in HIV+ and HIV- patients. Patients and Methods: This is a retrospective study conducted at the internal medicine department of CHU Ibn Sina in Rabat over a period of 12 years (2010–2021), collecting 42 cases of infectious uveitis. Results: 42 patients were identified. 34% (14 cases) had acquired immunosuppression (9 cases: 22% had HIV infection and 12% were on chemotherapy), and 66% were immunocompetent. The M/F sex ratio was 1.1. The average age was 39 years old. Uveitis revealed HIV in a single case; 8/9 patients have already been followed, their average viral load is 3.4 log and an average CD4 count is 356/mm³. The revealing functional signs were: ocular redness (27%), decreased visual acuity (63%), visual blurring (40%), ocular pain (18%), scotoma (13%), and headaches (4%). The uveitis was site: anterior (30%), intermediate (6%), posterior (32%), and pan-uveitis (32%); unilateral in 80% of patients and bilateral in 20%. The etiologies of uveitis in HIV+ were: 3 cases of CMV, 2 cases of toxoplasmosis, 1 case of tuberculosis, 1 case of HSV, 1 case of VZV, and 1 case of syphilis. Etiologies of immunocompetent patients: tuberculosis (41%), toxoplasmosis (18%), syphilis (15%), CMV infection (4 cases: 10%), HSV infection (4 cases: 10%) , lepromatous uveitis (1 case: 2%), VZV infection (1 case: 2%), a locoregional infectious cause such as dental abscess (1 case: 2%), and one case of borreliosis (3% ). 50% of tuberculous uveitis was of the pan-uveitis type, 75% of the uveitis by toxoplasmosis was of the posterior type. Uveitis was associated with other pathologies in 2 seropositive cases (cerebral vasculitis, multifocal tuberculosis). A specific treatment was prescribed in all patients. The initial evolution was favorable in 67%, including 12% HIV+. 11% presented relapses of the same seat during uveitis of the toxoplasmic, tuberculous and herpetic type. 47% presented complications, of which 4 patients were HIV+: 3 retinal detachments; 7 Retinal hemorrhages. 6 unilateral blindness (including 2 HIV+ patients). Conclusion: In our series, the etiologies of infectious uveitis differ between HIV+ and HIV- patients. In HIV+ patients most often had toxoplasmosis and CMV, while HIV - patients mainly presented with tuberculosis and toxoplasmosis. The association between HIV and uveitis is undetermined, but HIV infection was an independent risk factor for uveitis.Keywords: uveitis, HIV, immunosuppression, infection
Procedia PDF Downloads 853828 Characterization of Oxide Layer Developed during Tribo-Interaction of Zircaloys
Authors: Bharat Kumar, Deepak Kumar, Vijay Chaudhry
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Zirconium alloys are used as core components of nuclear reactors due to their high wear resistance, good corrosion properties, and good mechanical stability at high temperatures. The present work simulates the contact between the calandria tube and the liquid injection shutdown system (LISS) nozzle. The Calandria tube is the outer covering of the pressure tube. Water flows inside the pressure tube through fuel claddings which produces vibration in the pressure tube along with vibration in the calandria tube. Fretting wear takes place at the point of contact between the calandria tube and the LISS nozzle. Fretting tests were performed under different conditions, such as; varying fretting duration (i.e., 1 to 4 hours), varying frequency (i.e., 5 to 6.5 Hz), and varying amplitude (100 to 400 µm). The formation of the oxide layer was observed during the fretting wear test; as a result, the worn product. The worn surfaces were analyzed with scanning electron microscopy (SEM) to analyze the wear mechanism involved in the fretting test, and Energy dispersive x-ray spectroscopy (EDS) and Raman spectroscopy were used to confirm the presence of an oxide layer on the worn surface. The oxide layer becomes more uniform with fretting duration in case of water submerged condition as compared to dry contact condition. The oxide layer is deeply removed at high amplitude due to the change of wear mechanism from adhesion to abrasion, as confirmed by the presence of micro ploughing and micro cutting. Low amplitude fretting favors the formation of the tribo-oxide layer.Keywords: tribo-oxide layer, wear, mechanically mixed layer, zircaloy
Procedia PDF Downloads 723827 Association between Eating Behavior in Children Aged 7-10 Years Old and Their Mother’s Feeding Practice: A Study among the Families in Isfahan, Iran
Authors: Behnaz Farahani, Razieh Sotoudeh, Ali Vahdani, Hamed Abdi
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Individual differences in eating behavior can cause underweight or overweight and obesity. Thus influencing factors on children’s eating behavior such as mothers’ feeding practices are needed to be more investigated. The goals of this survey are to evaluate the association of (i) parental pressure and children’s food avoidant tendency, (ii) parental restriction and children’s food approach tendency, (iii) modeling of healthy eating in front of children and their children’s eating behavior. 760 mothers of children aged 7-10 from schools in Isfahan were asked to complete questionnaires including Child Feeding Questionnaire, Children’s Eating Behavior Questionnaire, Modeling Questionnaire, and self-administered demographic questionnaire in which mothers reported their children’s height and weight as well. Of those mothers, 745 completed the questionnaires for the children’s index (mean age: 8.513±1.112) during the 2011-2012 school year. The results of this quantitative, descriptive, cross-sectional analysis indicated that “parental restriction” was positively associated with child food responsiveness (P,0.000) and food enjoyment (P,0.000) and surprisingly, it was positively associated with Food Fussiness(0.000) .Parental pressure to eat was positively associated with child satiety responsiveness (P,0.000), slowness (P,0.000), and fussiness (P,0.00) and negatively associated with Food responsiveness(p,0.000)and Enjoyment of food (p,0.002), modeling of healthy eating were positively associated with Enjoyment of food / q (p,0.000) and negatively with food fussiness (P,0.000). The results of this survey will improve interventions and maternal guidance on their feeding practices and their association with children’s eating behavior and weight.Keywords: feeding practices, eating behavior, pressure to eat, restriction, modeling, satiety responsiveness, slowness in eating, food fussiness, food responsiveness, enjoyment of food
Procedia PDF Downloads 6103826 Study on the Thermal Mixing of Steam and Coolant in the Hybrid Safety Injection Tank
Authors: Sung Uk Ryu, Byoung Gook Jeon, Sung-Jae Yi, Dong-Jin Euh
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In such passive safety injection systems in the nuclear power plant as Core Makeup Tank (CMT) and Hybrid Safety Injection Tank, various thermal-hydraulic phenomena including the direct contact condensation of steam and the thermal stratification of coolant occur. These phenomena are also closely related to the performance of the system. Depending on the condensation rate of the steam injected to the tank, the injection of the coolant and pressure equalizing timings of the tank are decided. The steam injected to the tank from the upper nozzle penetrates the coolant and induces a direct contact condensation. In the present study, the direct contact condensation of steam and the thermal mixing between the steam and coolant were examined by using the Particle Image Velocimetry (PIV) technique. Especially, by altering the size of the nozzle from which the steam is injected, the influence of steam injection velocity on the thermal mixing with coolant and condensation shall be comprehended, while also investigating the influence of condensation on the pressure variation inside the tank. Even though the amounts of steam inserted were the same in three different nozzle size conditions, it was found that the velocity of pressure rise becomes lower as the steam injection area decreases. Also, as the steam injection area increases, the thickness of the zone within which the coolant’s temperature decreases. Thereby, the amount of steam condensed by the direct contact condensation also decreases. The results derived from the present study can be utilized for the detailed design of a passive safety injection system, as well as for modeling the direct contact condensation triggered by the steam jet’s penetration into the coolant.Keywords: passive safety injection systems, steam penetration, direct contact condensation, particle image velocimetry
Procedia PDF Downloads 3873825 A Concept of Data Mining with XML Document
Authors: Akshay Agrawal, Anand K. Srivastava
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The increasing amount of XML datasets available to casual users increases the necessity of investigating techniques to extract knowledge from these data. Data mining is widely applied in the database research area in order to extract frequent correlations of values from both structured and semi-structured datasets. The increasing availability of heterogeneous XML sources has raised a number of issues concerning how to represent and manage these semi structured data. In recent years due to the importance of managing these resources and extracting knowledge from them, lots of methods have been proposed in order to represent and cluster them in different ways.Keywords: XML, similarity measure, clustering, cluster quality, semantic clustering
Procedia PDF Downloads 3703824 Application of Electro-Optical Hybrid Cables in Horizontal Well Production Logging
Authors: Daofan Guo, Dong Yang
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For decades, well logging with coiled tubing has relied solely on surface data such as pump pressure, wellhead pressure, depth counter, and weight indicator readings. While this data serves the oil industry well, modern smart logging utilizes real-time downhole information, which automatically increases operational efficiency and optimizes intervention qualities. For example, downhole pressure, temperature, and depth measurement data can be transmitted through the electro-optical hybrid cable in the coiled tubing to surface operators on a real-time base. This paper mainly introduces the unique structural features and various applications of the electro-optical hybrid cables which were deployed into downhole with the help of coiled tubing technology. Fiber optic elements in the cable enable optical communications and distributed measurements, such as distributed temperature and acoustic sensing. The electrical elements provide continuous surface power for downhole tools, eliminating the limitations of traditional batteries, such as temperature, operating time, and safety concerns. The electrical elements also enable cable telemetry operation of cable tools. Both power supply and signal transmission were integrated into an electro-optical hybrid cable, and the downhole information can be captured by downhole electrical sensors and distributed optical sensing technologies, then travels up through an optical fiber to the surface, which greatly improves the accuracy of measurement data transmission.Keywords: electro-optical hybrid cable, underground photoelectric composite cable, seismic cable, coiled tubing, real-time monitoring
Procedia PDF Downloads 1313823 In the Study of Co₂ Capacity Performance of Different Frothing Agents through Process Simulation
Authors: Muhammad Idrees, Masroor Abro, Sikandar Almani
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Presently, the increasing CO₂ concentration in the atmosphere has been taken as one of the major challenges faced by the modern world. The average CO₂ in the atmosphere reached the highest value of 414.72 ppm in 2021, as reported in a conference of the parties (COP26). This study focuses on (i) the comparative study of MEA, NaOH, Acetic acid, and Na₂CO₃ in terms of their CO₂ capture performance, (ii) the significance of adding various frothing agents achieving improved absorption capacity of Na₂CO₃ and (iii) the overall economic evaluation of process with the help of Aspen Plus. The results obtained suggest that the addition of frothing agents significantly increased the absorption rate of dilute sodium carbonate such that from 45% to 99.9%. The effect of temperature, pressure and flow rate of liquid and flue gas streams on CO₂ absorption capacity was also investigated. It was found that the absorption capacity of Na₂CO₃ decreased with increasing temperature of the liquid stream and decreasing flow rate of the liquid stream and pressure of the gas stream.Keywords: CO₂, absorbents, frothing agents, process simulation
Procedia PDF Downloads 693822 Fabrication of Uniform Nanofibers Using Gas Dynamic Virtual Nozzle Based Microfluidic Liquid Jet System
Authors: R. Vasireddi, J. Kruse, M. Vakili, M. Trebbin
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Here we present a gas dynamic virtual nozzle (GDVN) based microfluidic jetting devices for spinning of nano/microfibers. The device is fabricated by soft lithography techniques and is based on the principle of a GDVN for precise three-dimensional gas focusing of the spinning solution. The nozzle device is used to produce micro/nanofibers of a perfluorinated terpolymer (THV), which were collected on an aluminum substrate for scanning electron microscopy (SEM) analysis. The influences of air pressure, polymer concentration, flow rate and nozzle geometry on the fiber properties were investigated. It was revealed that surface properties are controlled by air pressure and polymer concentration while the diameter and shape of the fibers are influenced mostly by the concentration of the polymer solution and pressure. Alterations of the nozzle geometry had a negligible effect on the fiber properties, however, the jetting stability was affected. Round and flat fibers with differing surface properties from craters, grooves to smooth surfaces could be fabricated by controlling the above-mentioned parameters. Furthermore, the formation of surface roughness was attributed to the fast evaporation rate and velocity (mis)match between the polymer solution jet and the surrounding air stream. The diameter of the fibers could be tuned from ~250 nm to ~15 µm. Because of the simplicity of the setup, the precise control of the fiber properties, access to biocompatible nanofiber fabrication and the easy scale-up of parallel channels for high throughput, this method offers significant benefits compared to existing solution-based fiber production methods.Keywords: gas dynamic virtual nozzle (GDVN) principle, microfluidic device, spinning, uniform nanofibers
Procedia PDF Downloads 1473821 Realization of Sustainable Urban Society by Personal Electric Transporter and Natural Energy
Authors: Yuichi Miyamoto
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In regards to the energy sector in the modern period, two points were raised. First is a vast and growing energy demand, and second is an environmental impact associated with it. The enormous consumption of fossil fuel to the mobile unit is leading to its rapid depletion. Nuclear power is not the only problem. A modal shift that utilizes personal transporters and independent power, in order to realize a sustainable society, is very effective. The paper proposes that the world will continue to work on this. Energy of the future society, innovation in battery technology and the use of natural energy is a big key. And it is also necessary in order to save on energy consumption.Keywords: natural energy, modal shift, personal transportation, battery
Procedia PDF Downloads 3993820 Implementation of a Low-Cost Instrumentation for an Open Cycle Wind Tunnel to Evaluate Pressure Coefficient
Authors: Cristian P. Topa, Esteban A. Valencia, Victor H. Hidalgo, Marco A. Martinez
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Wind tunnel experiments for aerodynamic profiles display numerous advantages, such as: clean steady laminar flow, controlled environmental conditions, streamlines visualization, and real data acquisition. However, the experiment instrumentation usually is expensive, and hence, each test implies a incremented in design cost. The aim of this work is to select and implement a low-cost static pressure data acquisition system for a NACA 2412 airfoil in an open cycle wind tunnel. This work compares wind tunnel experiment with Computational Fluid Dynamics (CFD) simulation and parametric analysis. The experiment was evaluated at Reynolds of 1.65 e5, with increasing angles from -5° to 15°. The comparison between the approaches show good enough accuracy, between the experiment and CFD, additional parametric analysis results differ widely from the other methods, which complies with the lack of accuracy of the lateral approach due its simplicity.Keywords: wind tunnel, low cost instrumentation, experimental testing, CFD simulation
Procedia PDF Downloads 1733819 Considerations When Using the Beach Chair Position for Surgery
Authors: Aniko Babits, Ahmad Daoud
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Introduction: The beach chair position (BCP) is a good approach to almost all types of shoulder procedures. However, moving an anaesthetized patient from the supine to sitting position may pose a risk of cerebral hypoperfusion and potential cerebral ischaemia as a result of significant reductions in blood pressure and cardiac output. Hypocapnia in ventilated patients and impaired blood flow to the vertebral artery due to hyperextension, rotation, or tilt of the head may have an impact too. Co-morbidities that may increase the risk of cerebral ischaemia in the BCP include diabetes with autonomic neuropathy, cerebrovascular disease, cardiac disease, severe hypertension, generalized vascular disease, history of fainting, and febrile conditions. Beach chair surgery requires a careful anaesthetic and surgical management to optimize patient safety and minimize the risk of adverse outcomes. Methods: We describe the necessary steps for optimal patient positioning and the aims of intraoperative management, including anaesthetic techniques to ensure patient safety in the BCP. Results: Regardless of the anaesthetic technique, adequate patient positioning is paramount in the BCP. The key steps to BCP are aimed at optimizing surgical success and minimizing the risk of severe neurovascular complications. The primary aim of anaesthetic management is to maintain cardiac output and mean arterial pressure (MAP) to protect cerebral perfusion. Blood pressure management includes treating a fall in MAP of more than 25% from baseline or a MAP less than 70 mmHg. This can be achieved by using intravenous fluids or vasopressors. A number of anaesthetic techniques could also improve cerebral oxygenation, including avoidance of intermittent positive pressure ventilation (IPPV) with general anaesthesia (GA), using regional anaesthesia, maintaining normocapnia and normothermia, and the application of compression stockings. Conclusions: In summary, BCP is a reliable and effective position to perform shoulder procedures. Simple steps to patient positioning and careful anaesthetic management could maximize patient safety and avoid unwanted adverse outcomes in patients undergoing surgery in BCP.Keywords: beach chair position, cerebral oxygenation, cerebral perfusion, sitting position
Procedia PDF Downloads 833818 Synthesis of High-Pressure Performance Adsorbent from Coconut Shells Polyetheretherketone for Methane Adsorption
Authors: Umar Hayatu Sidik
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Application of liquid base petroleum fuel (petrol and diesel) for transportation fuel causes emissions of greenhouse gases (GHGs), while natural gas (NG) reduces the emissions of greenhouse gases (GHGs). At present, compression and liquefaction are the most matured technology used for transportation system. For transportation use, compression requires high pressure (200–300 bar) while liquefaction is impractical. A relatively low pressure of 30-40 bar is achievable by adsorbed natural gas (ANG) to store nearly compressed natural gas (CNG). In this study, adsorbents for high-pressure adsorption of methane (CH4) was prepared from coconut shells and polyetheretherketone (PEEK) using potassium hydroxide (KOH) and microwave-assisted activation. Design expert software version 7.1.6 was used for optimization and prediction of preparation conditions of the adsorbents for CH₄ adsorption. Effects of microwave power, activation time and quantity of PEEK on the adsorbents performance toward CH₄ adsorption was investigated. The adsorbents were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric (TG) and derivative thermogravimetric (DTG) and scanning electron microscopy (SEM). The ideal CH4 adsorption capacities of adsorbents were determined using volumetric method at pressures of 5, 17, and 35 bar at an ambient temperature and 5 oC respectively. Isotherm and kinetics models were used to validate the experimental results. The optimum preparation conditions were found to be 15 wt% amount of PEEK, 3 minutes activation time and 300 W microwave power. The highest CH4 uptake of 9.7045 mmol CH4 adsorbed/g adsorbent was recorded by M33P15 (300 W of microwave power, 3 min activation time and 15 wt% amount of PEEK) among the sorbents at an ambient temperature and 35 bar. The CH4 equilibrium data is well correlated with Sips, Toth, Freundlich and Langmuir. Isotherms revealed that the Sips isotherm has the best fit, while the kinetics studies revealed that the pseudo-second-order kinetic model best describes the adsorption process. In all scenarios studied, a decrease in temperature led to an increase in adsorption of both gases. The adsorbent (M33P15) maintained its stability even after seven adsorption/desorption cycles. The findings revealed the potential of coconut shell-PEEK as CH₄ adsorbents.Keywords: adsorption, desorption, activated carbon, coconut shells, polyetheretherketone
Procedia PDF Downloads 633817 Biosensors as Analytical Tools in Legume Processing
Authors: S. V. Ncube, A. I. O. Jideani, E. T. Gwata
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The plight of food insecurity in developing countries has led to renewed interest in underutilized legumes. Their nutritional versatility, desirable functionality, pharmaceutical value and inherent bioactive compounds have drawn the attention of researchers. This has provoked the development of value added products with the aim of commercially exploiting their full potential. However processing of these legumes leads to changes in nutritional composition as affected by processing variables like pH, temperature and pressure. There is therefore a need for process control and quality assurance during production of the value added products. However, conventional methods for microbiological and biochemical identification are labour intensive and time-consuming. Biosensors offer rapid and affordable methods to assure the quality of the products. They may be used to quantify nutrients and anti-nutrients in the products while manipulating and monitoring variables such as pH, temperature, pressure and oxygen that affect the quality of the final product. This review gives an overview of the types of biosensors used in the food industry, their advantages and disadvantages and their possible application in processing of legumes.Keywords: legume processing, biosensors, quality control, nutritional versatility
Procedia PDF Downloads 4843816 Optimization of Supercritical CO2 Power Cycle for Waste Heat Recovery from Gas Turbine with Respect to Cooling Condition
Authors: Young Min Kim, Jeong Lak Sohn, Eui Soo Yoon
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This study describes the optimization of supercritical carbon dioxide (S-CO2) power cycle for recovering waste heat from a gas turbine. An S-CO2 cycle that recovers heat from small industrial and aeroderivative gas turbines can outperform a steam-bottoming cycle despite its simplicity and compactness. In using S-CO2 power cycles for waste heat recovery, a split cycle was studied to maximize the net output power by incorporating the utilization efficiency of the waste heat (lowering the temperature of the exhaust gas through the heater) along with the thermal efficiency of the cycle (minimizing the temperature difference for the heat transfer, exergy loss). The cooling condition of the S-CO2 WHR system has a great impact on the performance and the optimum low pressure of the system. Furthermore, the optimum high pressure of the S-CO2 WHR systems for the maximum power from the given heat sources is dependent on the temperature of the waste heat source.Keywords: exergy loss, gas turbine, optimization, supercritical CO2 power cycle, split cycle, waste heat recovery
Procedia PDF Downloads 3423815 Modeling Loads Applied to Main and Crank Bearings in the Compression-Ignition Two-Stroke Engine
Authors: Marcin Szlachetka, Mateusz Paszko, Grzegorz Baranski
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This paper discusses the AVL EXCITE Designer simulation research into loads applied to main and crank bearings in the compression-ignition two-stroke engine. There was created a model of engine lubrication system which covers the part of this system related to particular nodes of a bearing system, i.e. a connection of main bearings in an engine block with a crankshaft, a connection of crank pins with a connecting rod. The analysis focused on the load given as a distribution of hydrodynamic oil film pressure corresponding different values of radial internal clearance. There was also studied the impact of gas force on minimal oil film thickness in main and crank bearings versus crankshaft rotational speed. Our model calculates oil film parameters, an oil film pressure distribution, an oil temperature change and dimensions of bearings as well as an oil temperature distribution on surfaces of bearing seats. Accordingly, it was possible to select, for example, a correct clearance for each of the node bearings. The research was performed for several values of engine crankshaft speed ranging from 800 RPM to 4000 RPM. Bearing oil pressure was changed according to engine speed ranging between 1 bar and 5 bar and an oil temperature of 90°C. The main bearing clearances made initially for the calculation and research were: 0.015 mm, 0.025 mm, 0.035 mm, 0.05 mm, 0.1 mm. The oil used for the research corresponded the SAE 5W-40 classification. The paper presents the selected research results referring to certain specific operating points and bearing radial internal clearances. Acknowledgement: This work has been realized in the cooperation with The Construction Office of WSK ‘PZL-KALISZ’ S.A. and is part of Grant Agreement No. POIR.01.02.00-00-0002/15 financed by the Polish National Centre for Research and Development.Keywords: crank bearings, diesel engine, oil film, two-stroke engine
Procedia PDF Downloads 2063814 Flow of a Second Order Fluid through Constricted Tube with Slip Velocity at Wall Using Integral Method
Authors: Nosheen Zareen Khan, Abdul Majeed Siddiqui, Muhammad Afzal Rana
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The steady flow of a second order fluid through constricted tube with slip velocity at wall is modeled and analyzed theoretically. The governing equations are simplified by implying no slip in radial direction. Based on Karman Pohlhausen procedure polynomial solution for axial velocity profile is presented. An expressions for pressure gradient, shear stress, separation and reattachment points and radial velocity are also calculated. The effect of slip and no slip velocity on velocity, shear stress, pressure gradient are discussed and depicted graphically. It is noted that when Reynolds number increases velocity of the fluid decreases in both slip and no slip conditions. It is also found that the wall shear stress, separation and reattachment points are strongly effected by Reynolds number.Keywords: approximate solution, constricted tube, non-Newtonian fluids, Reynolds number
Procedia PDF Downloads 3893813 Probabilistic and Stochastic Analysis of a Retaining Wall for C-Φ Soil Backfill
Authors: André Luís Brasil Cavalcante, Juan Felix Rodriguez Rebolledo, Lucas Parreira de Faria Borges
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A methodology for the probabilistic analysis of active earth pressure on retaining wall for c-Φ soil backfill is described in this paper. The Rosenblueth point estimate method is used to measure the failure probability of a gravity retaining wall. The basic principle of this methodology is to use two point estimates, i.e., the standard deviation and the mean value, to examine a variable in the safety analysis. The simplicity of this framework assures to its wide application. For the calculation is required 2ⁿ repetitions during the analysis, since the system is governed by n variables. In this study, a probabilistic model based on the Rosenblueth approach for the computation of the overturning probability of failure of a retaining wall is presented. The obtained results have shown the advantages of this kind of models in comparison with the deterministic solution. In a relatively easy way, the uncertainty on the wall and fill parameters are taken into account, and some practical results can be obtained for the retaining structure design.Keywords: retaining wall, active earth pressure, backfill, probabilistic analysis
Procedia PDF Downloads 4093812 Solar Aided Vacuum Desalination of Sea-Water
Authors: Miraz Hafiz Rossy
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As part of planning to address shortfalls in fresh water supply for the world, Sea water can be a huge source of fresh water. But Desalinating sea water to get fresh water could require a lots of fossil fuels. To save the fossil fuel in terms of save the green world but meet the up growing need for fresh water, a very useful but energy efficient method needs to be introduced. Vacuum desalination of sea water using only the Renewable energy can be an effective solution to this issue. Taking advantage of sensitivity of water's boiling point to air pressure a vacuum desalination water treatment plant can be designed which would only use sea water as feed water and solar energy as fuel to produce fresh drinking water. The study indicates that reducing the air pressure to a certain value water can be boiled at very low temperature. Using solar energy to provide the condensation and the vacuum creation would be very useful and efficient. Compared to existing resources, desalination is considered to be expensive, but using only renewable energy the cost can be reduced significantly. Despite its very few drawbacks, it can be considered a possible solution to the world's fresh water shortages.Keywords: desalination, scarcity of fresh water, water purification, water treatment
Procedia PDF Downloads 3783811 Analysis of Wall Deformation of the Arterial Plaque Models: Effects of Viscoelasticity
Authors: Eun Kyung Kim, Kyehan Rhee
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Viscoelastic wall properties of the arterial plaques change as the disease progresses, and estimation of wall viscoelasticity can provide a valuable assessment tool for plaque rupture prediction. Cross section of the stenotic coronary artery was modeled based on the IVUS image, and the finite element analysis was performed to get wall deformation under pulsatile pressure. The effects of viscoelastic parameters of the plaque on luminal diameter variations were explored. The result showed that decrease of viscous effect reduced the phase angle between the pressure and displacement waveforms, and phase angle was dependent on the viscoelastic properties of the wall. Because viscous effect of tissue components could be identified using the phase angle difference, wall deformation waveform analysis may be applied to predict plaque wall composition change and vascular wall disease progression.Keywords: atherosclerotic plaque, diameter variation, finite element method, viscoelasticity
Procedia PDF Downloads 2113810 Non-Linear Transformation of Bulk Acoustic Waves at Oblique Incidence on Plane Solid Boundary
Authors: Aleksandr I. Korobov, Natalia V. Shirgina, Aleksey I. Kokshaiskiy
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The transformation of two types of acoustic waves can occur on a flat interface between two solids at oblique incidence of longitudinal and shear bulk acoustic waves (BAW). This paper presents the results of experimental studies of the properties of reflection and propagation of longitudinal wave and generation of second and third longitudinal and shear harmonics of BAW at oblique incidence of longitudinal BAW on a flat rough boundary between two solids. The experimental sample was a rectangular isosceles pyramid made of D16 aluminum alloy with the plane parallel bases cylinder made of D16 aluminum alloy pressed to the base. The piezoelectric lithium niobate transducer with a resonance frequency of 5 MHz was secured to one face of the pyramid to generate a longitudinal wave. Longitudinal waves emitted by this transducer felt at an angle of 45° to the interface between two solids and reflected at the same angle. On the opposite face of the pyramid, and on the flat side of the cylinder was attached longitudinal transducer with resonance frequency of 10 MHz or the shear transducer with resonance frequency of 15 MHz. These transducers also effectively received signal at a frequency of 5 MHz. In the spectrum of the transmitted and reflected BAW was observed shear and longitudinal waves at a frequency of 5 MHz, as well as longitudinal harmonic at a frequency harmonic of 10 MHz and a shear harmonic at frequency of 15 MHz. The effect of reversing changing of external pressure applied to the rough interface between two solids on the value of the first and higher harmonics of the BAW at oblique incidence on the interface of the longitudinal BAW was experimentally investigated. In the spectrum of the reflected signal from the interface, there was a decrease of amplitudes of the first harmonics of the signal, and non-monotonic dependence of the second and third harmonics of shear wave with an increase of the static pressure applied to the interface. In the spectrum of the transmitted signal growth of the first longitudinal and shear harmonic amplitude and non-monotonic dependence - first increase and then decrease in the amplitude of the second and third longitudinal shear harmonic with increasing external static pressure was observed. These dependencies were hysteresis at reversing changing of external pressure. When pressure applied to the border increased, acoustic contact between the surfaces improves. This increases the energy of the transmitted elastic wave and decreases the energy of the reflected wave. The second longitudinal acoustic harmonics generation was associated with the Hertz nonlinearity on the interface of two pressed rough surfaces, the generation of the third harmonic was caused by shear hysteresis nonlinearity due to dry friction on a rough interface. This study was supported by the Russian Science Foundation (project №14-22-00042).Keywords: generation of acoustic harmonics, hysteresis nonlinearity, Hertz nonlinearity, transformation of acoustic waves
Procedia PDF Downloads 3743809 Computational Fluids Dynamics Investigation of the Effect of Geometric Parameters on the Ejector Performance
Authors: Michel Wakim, Rodrigo Rivera Tinoco
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Supersonic ejector is an economical device that use high pressure vapor to compress a low pressure vapor without any rotating parts or external power sources. Entrainment ratio is a major characteristic of the ejector performance, so the ejector performance is highly dependent on its geometry. The aim of this paper is to design ejector geometry, based on pre-specified operating conditions, and to study the flow behavior inside the ejector by using computational fluid dynamics ‘CFD’ by using ‘ANSYS FLUENT 15.0’ software. In the first section; 1-D mathematical model is carried out to predict the ejector geometry. The second part describes the flow behavior inside the designed model. CFD is the most reliable tool to reveal the mixing process at different parts of the supersonic turbulent flow and to study the effect of the geometry on the effective ejector area. Finally, the results show the effect of the geometry on the entrainment ratio.Keywords: computational fluids dynamics, ejector, entrainment ratio, geometry optimization, performance
Procedia PDF Downloads 2683808 The Situation in Afghanistan as a Step Forward in Putting an End to Impunity
Authors: Jelena Radmanovic
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On 5 March 2020, the International Criminal Court has decided to authorize the investigation into the crimes allegedly committed on the territory of Afghanistan after 1 May 2003. The said determination has raised several controversies, including the recently imposed sanctions by the United States, furthering the United States' long-standing rejection of the authority of the International Criminal Court. The purpose of this research is to address the said investigation in light of its importance for the prevention of impunity in the cases where the perpetrators are nationals of Non-Party States to the Rome Statute. Difficulties that the International Criminal Court has been facing, concerning the establishment of its jurisdiction in those instances where an involved state is not a Party to the Rome Statute, have become the most significant stumbling block undermining the importance, integrity, and influence of the Court. The Situation in Afghanistan raises even further concern, bearing in mind that the Prosecutor’s Request for authorization of an investigation pursuant to article 15 from 20 November 2017 has initially been rejected with the ‘interests of justice’ as an applied rationale. The first method used for the present research is the description of the actual events regarding the aforementioned decisions and the following reactions in the international community, while with the second method – the method of conceptual analysis, the research will address the decisions pertaining to the International Criminal Court’s jurisdiction and will attempt to address the mentioned Decision of 5 March 2020 as an example of good practice and a precedent that should be followed in all similar situations. The research will attempt parsing the reasons used by the International Criminal Court, giving rather greater attention to the latter decision that has authorized the investigation and the points raised by the officials of the United States. It is a find of this research that the International Criminal Court, together with other similar judicial instances (Nuremberg and Tokyo Tribunals, The International Criminal Tribunal for the former Yugoslavia, The International Criminal Tribunal for Rwanda), has presented the world with the possibility of non-impunity, attempting to prosecute those responsible for the gravest of crimes known to the humanity and has shown that such persons should not enjoy the benefits of their immunities, with its focus primarily on the victims of such crimes. Whilst it is an issue that will most certainly be addressed further in the future, with the situations that will be brought before the International Criminal Court, the present research will make an attempt at pointing to the significance of the situation in Afghanistan, the International Criminal Court as such and the international criminal justice as a whole, for the purpose of putting an end to impunity.Keywords: Afghanistan, impunity, international criminal court, sanctions, United States
Procedia PDF Downloads 1183807 Performance Analysis of a Shell and Tube Heat Exchanger in the Organic Rankine Cycle Power Plant
Authors: Yogi Sirodz Gaos, Irvan Wiradinata
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In the 500 kW Organic Rankine Cycle (ORC) power plant in Indonesia, an AFT (according to the Tubular Exchanger Manufacturers Association – TEMA) type shell and tube heat exchanger device is used as a pre-heating system for the ORC’s hot water circulation system. The pre-heating source is a waste heat recovery of the brine water, which is tapped from a geothermal power plant. The brine water itself has 5 MWₜₕ capacities, with average temperature of 170ᵒC, and 7 barg working pressure. The aim of this research is to examine the performance of the heat exchanger in the ORC system in a 500 kW ORC power plant. The data for this research were collected during the commissioning on the middle of December 2016. During the commissioning, the inlet temperature and working pressure of the brine water to the shell and tube type heat exchanger was 149ᵒC, and 4.4 barg respectively. Furthermore, the ΔT for the hot water circulation of the ORC system to the heat exchanger was 27ᵒC, with the inlet temperature of 140ᵒC. The pressure in the hot circulation system was dropped slightly from 7.4ᵒC to 7.1ᵒC. The flow rate of the hot water circulation was 80.5 m³/h. The presentation and discussion of a case study on the performance of the heat exchanger on the 500 kW ORC system is presented as follows: (1) the heat exchange duty is 2,572 kW; (2) log mean temperature of the heat exchanger is 13.2ᵒC; (3) the actual overall thermal conductivity is 1,020.6 W/m².K (4) the required overall thermal conductivity is 316.76 W/m².K; and (5) the over design for this heat exchange performance is 222.2%. An analysis of the heat exchanger detailed engineering design (DED) is briefly discussed. To sum up, this research concludes that the shell and tube heat exchangers technology demonstrated a good performance as pre-heating system for the ORC’s hot water circulation system. Further research need to be conducted to examine the performance of heat exchanger system on the ORC’s hot water circulation system.Keywords: shell and tube, heat exchanger, organic Rankine cycle, performance, commissioning
Procedia PDF Downloads 1403806 An Improved Single Point Closure Model Based on Dissipation Anisotropy for Geophysical Turbulent Flows
Authors: A. P. Joshi, H. V. Warrior, J. P. Panda
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This paper is a continuation of the work carried out by various turbulence modelers in Oceanography on the topic of oceanic turbulent mixing. It evaluates the evolution of ocean water temperature and salinity by the appropriate modeling of turbulent mixing utilizing proper prescription of eddy viscosity. Many modelers in past have suggested including terms like shear, buoyancy and vorticity to be the parameters that decide the slow pressure strain correlation. We add to it the fact that dissipation anisotropy also modifies the correlation through eddy viscosity parameterization. This recalibrates the established correlation constants slightly and gives improved results. This anisotropization of dissipation implies that the critical Richardson’s number increases much beyond unity (to 1.66) to accommodate enhanced mixing, as is seen in reality. The model is run for a couple of test cases in the General Ocean Turbulence Model (GOTM) and the results are presented here.Keywords: Anisotropy, GOTM, pressure-strain correlation, Richardson critical number
Procedia PDF Downloads 1633805 Microfluidic Method for Measuring Blood Viscosity
Authors: Eunseop Yeom
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Many cardiovascular diseases, such as thrombosis and atherosclerosis, can change biochemical molecules in plasma and red blood cell. These alterations lead to excessive increase of blood viscosity contributing to peripheral vascular diseases. In this study, a simple microfluidic-based method is used to measure blood viscosity. Microfluidic device is composed of two parallel side channels and a bridge channel. To estimate blood viscosity, blood samples and reference fluid are separately delivered into each inlet of two parallel side channels using pumps. An interfacial line between blood samples and reference fluid occurs by blocking the outlet of one side-channel. Since width for this interfacial line is determined by pressure ratio between blood and reference flows, blood viscosity can be estimated by measuring width for this interfacial line. This microfluidic-based method can be used for evaluating variations in the viscosity of animal models with cardiovascular diseases under flow conditions.Keywords: blood viscosity, microfluidic chip, pressure, shear rate
Procedia PDF Downloads 3623804 Experimental Study on Hardness and Impact Strength of Polyethylene/Carbon Composites
Authors: Armin Najipour, A. M. Fattahi
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The aim of this research was to investigate the effect of the addition of multi walled carbon nanotubes on the mechanical properties of polyethylene/carbon nanotube nanocomposites. To do so, polyethylene and carbon nanotube were mixed in different weight percentages containing 0, 0.5, 1, and 1.5% carbon nanotube in two screw extruder apparatus by fusion. Then the nanocomposite samples were molded in injection apparatus according to ASTM: D6110 standard. The effects of carbon nanotube addition in 4 different levels and injection pressure in 2 levels on the hardness and impact strength of the nanocomposite samples were investigated. The results showed that the addition of carbon nanotube had a significant effect on improving hardness and impact strength of the nanocomposite samples such that by adding 1% w/w carbon nanotube, the impact strength and hardness of the samples improved to 74% and 46.7% respectively. Also, according to the results, the effect of injection pressure on the results was much less than that of carbon nanotube weight percentage.Keywords: carbon nanotube, injection molding, mechanical properties, nanocomposite, polyethylene
Procedia PDF Downloads 3113803 Experimental Study on the Preparation of Pelletizing of the Panzhihua's Fine Ilmenite Concentrate
Authors: Han Kexi, Lv Xuewei, Song Bing
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This paper focuses on the preparation of pelletizing with the Panzhihua ilmenite concentrate to satisfy the requirement of smelting titania slag. The effects of the moisture content, mixing time of raw materials, pressure of pellet, roller rotating speed of roller, drying temperature and time on the pelletizing yield and compressive strength were investigated. The experimental results show that the moister content was controlled at 2.0%~2.5%, mixing time at 20 min, the pressure of the ball forming machine at 13~15 mpa, the pelletizing yield can reach up 85%. When the roller rotating speed is 6~8 r/min while the drying temperature and time respectively is 350 ℃ and 40~60 min, the compressive strength of pelletizing more than 1500 N. The preparation of pelletizing can meet the requirement of smelting titania slag.Keywords: Panzhihua fine ilmenite concentrate, pelletizing, pelletizing yield, compressive strength, drying
Procedia PDF Downloads 2123802 Effect pH on Chemical and Physical Properties of Iranian Fetta Cheese
Authors: M. Dezyani, R. Ezzati, H. Mirzaei
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The objectives of this study were to determine the effect of pH on chemical, structural, and functional properties of Fetta cheese, and to relate changes in structure to changes in cheese unctionality. Fetta cheese was obtained from a cheese-production facility and stored at 4°C. Ten days after manufacture, the cheese was cut into blocks that were vacuum-packaged and stored for 4 d at 4°C. Cheese blocks were then high-pressure injected one, three, or five times with a 20% (wt/wt) glucono-δ-lactone solution. Successive injections were performed 24 h apart. Cheese blocks were then analyzed after 40 d of storage at 4°C. Acidulant injection decreased cheese pH from 5.3 in the uninjected cheese to 4.7 after five injections. Decreased pH increased the content of soluble calcium and slightly decreased the total calcium content of cheese. At the highest level, injection of acidulant promoted syneresis. Thus, after five injections, the moisture content of cheese decreased from 34 to 31%, which esulted in decreased cheese weight. Lowered cheese pH, 4.7 compared with 5.3, also resulted in contraction of the protein matrix. Acidulant injection decreased cheese hardness and cohesiveness, and the cheese became more crumbly.Keywords: calcium, high-pressure injection, protein matrix, syneresis
Procedia PDF Downloads 471