Search results for: alternative phase opposition disposition (APOD)
7561 Analysis of Two-Phase Flow Instabilities in Conventional Channel of Nuclear Power Reactor
Authors: M. Abdur Rashid Sarkar, Riffat Mahmud
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Boiling heat transfer plays a crucial role in cooling nuclear reactor for safe electricity generation. A two phase flow is susceptible to thermal-hydrodynamic instabilities, which may cause flow oscillations of constant amplitude or diverging amplitude. These oscillations may induce boiling crisis, disturb control systems, or cause mechanical damage. Based on their mechanisms, various types of instabilities can be classified for a nuclear reactor. From a practical engineering point of view one of the major design difficulties in dealing with multiphase flow is that the mass, momentum, and energy transfer rates and processes may be quite sensitive to the geometric configuration of the heat transfer surface. Moreover, the flow within each phase or component will clearly depend on that geometric configuration. The complexity of this two-way coupling presents a major challenge in the study of multiphase flows and there is much that remains to be done. Yet, the parametric effects on flow instability such as the effect of aspect ratio, pressure drop, channel length, its orientation inlet subcooling and surface roughness etc. have been analyzed. Another frequently occurring instability, known as the Kelvin–Helmholtz instability has been briefly reviewed. Various analytical techniques for predicting parametric effect on the instability are analyzed in terms of their applicability and accuracy.Keywords: two phase flows, boiling crisis, thermal-hydrodynamic instabilities, water cooled nuclear reactors, kelvin–helmholtz instability
Procedia PDF Downloads 3997560 Coarse-Grained Molecular Simulations to Estimate Thermophysical Properties of Phase Equilibria
Authors: Hai Hoang, Thanh Xuan Nguyen Thi, Guillaume Galliero
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Coarse-Grained (CG) molecular simulations have shown to be an efficient way to estimate thermophysical (static and dynamic) properties of fluids. Several strategies have been developed and reported in the literature for defining CG molecular models. Among them, those based on a top-down strategy (i.e. CG molecular models related to macroscopic observables), despite being heuristic, have increasingly gained attention. This is probably due to its simplicity in implementation and its ability to provide reasonable results for not only simple but also complex systems. Regarding simple Force-Fields associated with these CG molecular models, it has been found that the four parameters Mie chain model is one of the best compromises to describe thermophysical static properties (e.g. phase diagram, saturation pressure). However, parameterization procedures of these Mie-chain GC molecular models given in literature are generally insufficient to simultaneously provide static and dynamic (e.g. viscosity) properties. To deal with such situations, we have extended the corresponding states by using a quantity associated with the liquid viscosity. Results obtained from molecular simulations have shown that our approach is able to yield good estimates for both static and dynamic thermophysical properties for various real non-associating fluids. In addition, we will show that on simple (e.g. phase diagram, saturation pressure) and complex (e.g. thermodynamic response functions, thermodynamic energy potentials) static properties, results of our scheme generally provides improved results compared to existing approaches.Keywords: coarse-grained model, mie potential, molecular simulations, thermophysical properties, phase equilibria
Procedia PDF Downloads 3367559 Energy Conservation and H-Theorem for the Enskog-Vlasov Equation
Authors: Eugene Benilov, Mikhail Benilov
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The Enskog-Vlasov (EV) equation is a widely used semi-phenomenological model of gas/liquid phase transitions. We show that it does not generally conserve energy, although there exists a restriction on its coefficients for which it does. Furthermore, if an energy-preserving version of the EV equation satisfies an H-theorem as well, it can be used to rigorously derive the so-called Maxwell construction which determines the parameters of liquid-vapor equilibria. Finally, we show that the EV model provides an accurate description of the thermodynamics of noble fluids, and there exists a version simple enough for use in applications.Keywords: Enskog collision integral, hard spheres, kinetic equation, phase transition
Procedia PDF Downloads 1557558 Temperature Control and Thermal Management of Cylindrical Lithium Batteries Using Phase Change Materials (PCMs)
Authors: S. M. Sadrameli, Y. Azizi
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Lithium-ion batteries (LIBs) have shown to be one of the most reliable energy storage systems for electric cars in the recent years. Ambient temperature has a significant impact on the performance, lifetime, safety and cost of such batteries. Increasing the temperature degrade the lithium batteries more quickly while working at low-temperature environment results reducing the power and energy capability of the system. A thermal management system has been designed and setup in laboratory scale for controlling the temperature at optimum conditions using PEG-1000 with the melting point in the range of 33-40 oC as a phase change material. Aluminum plates have been installed in the PCM to increase the thermal conductivity and increasing the heat transfer rate. Experimental tests have been run at different discharge rates and ambient temperatures to investigate the effects of temperature on the efficiency of the batteries. The comparison has been made between the system of 6 batteries with and without PCM and the results show that PCM with aluminum plates decrease the surface temperature of the batteries that would result better performance and longer lifetime of the batteries.Keywords: lithium-ion batteries, phase change materials, thermal management, temperature control
Procedia PDF Downloads 3427557 Computational Fluid Dynamics Simulation of Gas-Liquid Phase Stirred Tank
Authors: Thiyam Tamphasana Devi, Bimlesh Kumar
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A Computational Fluid Dynamics (CFD) technique has been applied to simulate the gas-liquid phase in double stirred tank of Rushton impeller. Eulerian-Eulerian model was adopted to simulate the multiphase with standard correlation of Schiller and Naumann for drag co-efficient. The turbulence was modeled by using standard k-ε turbulence model. The present CFD model predicts flow pattern, local gas hold-up, and local specific area. It also predicts local kLa (mass transfer rate) for single impeller. The predicted results were compared with experimental and CFD results of published literature. The predicted results are slightly over predicted with the experimental results; however, it is in reasonable agreement with other simulated results of published literature.Keywords: Eulerian-Eulerian, gas-hold up, gas-liquid phase, local mass transfer rate, local specific area, Rushton Impeller
Procedia PDF Downloads 2367556 Defects Classification of Stator Coil Generators by Phase Resolve Partial Discharge
Authors: Chun-Yao Lee, Nando Purba, Benny Iskandar
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This paper proposed a phase resolve partial discharge (PRPD) shape method to classify types of defect stator coil generator by using off-line PD measurement instrument. The recorded PRPD, by using the instruments MPD600, can illustrate the PRPD patterns of partial discharge of unit’s defects. In the paper, two of large units, No.2 and No.3, in Inalum hydropower plant, North Sumatera, Indonesia is adopted in the experimental measurement. The proposed PRPD shape method is to mark auxiliary lines on the PRPD patterns. The shapes of PRPD from two units are marked with the proposed method. Then, four types of defects in IEC 60034-27 standard is adopted to classify the defect types of the two units, which types are microvoids (S1), delamination tape layer (S2), slot defect (S3) and internal delamination (S4). Finally, the two units are actually inspected to validate the availability of the proposed PRPD shape method.Keywords: partial discharge (PD), stator coil, defect, phase resolve pd (PRPD)
Procedia PDF Downloads 2647555 Representation of the Kurdish Opposition: From Periphery to Center
Authors: Songul Miftakhov
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This study explores political representation and engagement of Eastern and Southeastern Anatolia regions, known to have dense Kurdish population and referred further to as Eastern region, in the Turkish parliament between 1946 and 1980. Traditional local notables had most of the privileges to be represented given their connectedness with political parties. Traditional local notables integrated into right-wing parties considering political and economic aspects. At the same time, they kept control over local political involvement channels. As a result, political representation and presence were monopolized at central, local and civil society levels. One part of Kurdish intellectuals was marginalized from the parliament after addressing issues in Eastern Anatolia and trying to develop solutions apart from the mainstream. Some of them took part in Kurdish oppositional left wing in the 1960s and jounced power of settled notables in 1970s in local administrations or as independent members of the parliament.Keywords: Kurdish representation, parliament, local nobles, Eastern and Southeastern Anatolia
Procedia PDF Downloads 1537554 Study Technical Possibilities of Agricultural Reuse of by-Products from Treatment Plant of Boumerdes, Algeria
Authors: Kadir Mokrane, Souag Doudja
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In Algeria, one of the Mediterranean countries, water resources are limited and unevenly distributed in space and in time. Boumerdes, coastal town of Algeria, known for its farming and fishing activities. The region is also known for its semi-arid climate and a large water deficit. In order to preserve the quality of water bodies and to reduce withdrawals in the natural environment, it is necessary to seek alternative supplies. The reuse of treated wastewater seems to be a good alternative, especially for irrigation. In the framework of sustainable development, it is imperative to rationalize the use of water resources conventional and unconventional. That is why the re-use agricultural of by-products of the treatment is an alternative expected to preserve the environment and promotion of the agricultural sector. The present work aims, to search for the possibility of reuse of treated wastewater, and sludge resulting from treatment plant of the city of Boumerdes in agriculture, through the analysis of physical, chemical and bacteriological on the samples, and the continuous monitoring of the evolution of several elements during the period of study extended over 12 months, and then, the comparison of these test results to standards and guidelines established in the framework of irrigation and land application.Keywords: treated water, sewage sludge, recycling, agriculture
Procedia PDF Downloads 2497553 2D CFD-PBM Coupled Model of Particle Growth in an Industrial Gas Phase Fluidized Bed Polymerization Reactor
Authors: H. Kazemi Esfeh, V. Akbari, M. Ehdaei, T. N. G. Borhani, A. Shamiri, M. Najafi
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In an industrial fluidized bed polymerization reactor, particle size distribution (PSD) plays a significant role in the reactor efficiency evaluation. The computational fluid dynamic (CFD) models coupled with population balance equation (CFD-PBM) have been extensively employed to investigate the flow behavior in the poly-disperse multiphase fluidized bed reactors (FBRs) utilizing ANSYS Fluent code. In this study, an existing CFD-PBM/ DQMOM coupled modeling framework has been used to highlight its potential to analyze the industrial-scale gas phase polymerization reactor. The predicted results reveal an acceptable agreement with the observed industrial data in terms of pressure drop and bed height. The simulated results also indicate that the higher particle growth rate can be achieved for bigger particles. Hence, the 2D CFD-PBM/DQMOM coupled model can be used as a reliable tool for analyzing and improving the design and operation of the gas phase polymerization FBRs.Keywords: computational fluid dynamics, population balance equation, fluidized bed polymerization reactor, direct quadrature method of moments
Procedia PDF Downloads 3687552 Analysis of an Alternative Data Base for the Estimation of Solar Radiation
Authors: Graciela Soares Marcelli, Elison Eduardo Jardim Bierhals, Luciane Teresa Salvi, Claudineia Brazil, Rafael Haag
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The sun is a source of renewable energy, and its use as both a source of heat and light is one of the most promising energy alternatives for the future. To measure the thermal or photovoltaic systems a solar irradiation database is necessary. Brazil still has a reduced number of meteorological stations that provide frequency tests, as an alternative to the radio data platform, with reanalysis systems, quite significant. ERA-Interim is a global fire reanalysis by the European Center for Medium-Range Weather Forecasts (ECMWF). The data assimilation system used for the production of ERA-Interim is based on a 2006 version of the IFS (Cy31r2). The system includes a 4-dimensional variable analysis (4D-Var) with a 12-hour analysis window. The spatial resolution of the dataset is approximately 80 km at 60 vertical levels from the surface to 0.1 hPa. This work aims to make a comparative analysis between the ERA-Interim data and the data observed in the Solarimmetric Atlas of the State of Rio Grande do Sul, to verify its applicability in the absence of an observed data network. The analysis of the results obtained for a study region as an alternative to the energy potential of a given region.Keywords: energy potential, reanalyses, renewable energy, solar radiation
Procedia PDF Downloads 1647551 Optimization Model for Identification of Assembly Alternatives of Large-Scale, Make-to-Order Products
Authors: Henrik Prinzhorn, Peter Nyhuis, Johannes Wagner, Peter Burggräf, Torben Schmitz, Christina Reuter
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Assembling large-scale products, such as airplanes, locomotives, or wind turbines, involves frequent process interruptions induced by e.g. delayed material deliveries or missing availability of resources. This leads to a negative impact on the logistical performance of a producer of xxl-products. In industrial practice, in case of interruptions, the identification, evaluation and eventually the selection of an alternative order of assembly activities (‘assembly alternative’) leads to an enormous challenge, especially if an optimized logistical decision should be reached. Therefore, in this paper, an innovative, optimization model for the identification of assembly alternatives that addresses the given problem is presented. It describes make-to-order, large-scale product assembly processes as a resource constrained project scheduling (RCPS) problem which follows given restrictions in practice. For the evaluation of the assembly alternative, a cost-based definition of the logistical objectives (delivery reliability, inventory, make-span and workload) is presented.Keywords: assembly scheduling, large-scale products, make-to-order, optimization, rescheduling
Procedia PDF Downloads 4597550 3D CFD Model of Hydrodynamics in Lowland Dam Reservoir in Poland
Authors: Aleksandra Zieminska-Stolarska, Ireneusz Zbicinski
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Introduction: The objective of the present work was to develop and validate a 3D CFD numerical model for simulating flow through 17 kilometers long dam reservoir of a complex bathymetry. In contrast to flowing waters, dam reservoirs were not emphasized in the early years of water quality modeling, as this issue has never been the major focus of urban development. Starting in the 1970s, however, it was recognized that natural and man-made lakes are equal, if not more important than estuaries and rivers from a recreational standpoint. The Sulejow Reservoir (Central Poland) was selected as the study area as representative of many lowland dam reservoirs and due availability of a large database of the ecological, hydrological and morphological parameters of the lake. Method: 3D, 2-phase and 1-phase CFD models were analysed to determine hydrodynamics in the Sulejow Reservoir. Development of 3D, 2-phase CFD model of flow requires a construction of mesh with millions of elements and overcome serious convergence problems. As 1-phase CFD model of flow in relation to 2-phase CFD model excludes from the simulations the dynamics of waves only, which should not change significantly water flow pattern for the case of lowland, dam reservoirs. In 1-phase CFD model, the phases (water-air) are separated by a plate which allows calculations of one phase (water) flow only. As the wind affects velocity of flow, to take into account the effect of the wind on hydrodynamics in 1-phase CFD model, the plate must move with speed and direction equal to the speed and direction of the upper water layer. To determine the velocity at which the plate will move on the water surface and interacts with the underlying layers of water and apply this value in 1-phase CFD model, the 2D, 2-phase model was elaborated. Result: Model was verified on the basis of the extensive flow measurements (StreamPro ADCP, USA). Excellent agreement (an average error less than 10%) between computed and measured velocity profiles was found. As a result of work, the following main conclusions can be presented: •The results indicate that the flow field in the Sulejow Reservoir is transient in nature, with swirl flows in the lower part of the lake. Recirculating zones, with the size of even half kilometer, may increase water retention time in this region •The results of simulations confirm the pronounced effect of the wind on the development of the water circulation zones in the reservoir which might affect the accumulation of nutrients in the epilimnion layer and result e.g. in the algae bloom. Conclusion: The resulting model is accurate and the methodology develop in the frame of this work can be applied to all types of storage reservoir configurations, characteristics, and hydrodynamics conditions. Large recirculating zones in the lake which increase water retention time and might affect the accumulation of nutrients were detected. Accurate CFD model of hydrodynamics in large water body could help in the development of forecast of water quality, especially in terms of eutrophication and water management of the big water bodies.Keywords: CFD, mathematical modelling, dam reservoirs, hydrodynamics
Procedia PDF Downloads 4017549 Epileptic Seizure Prediction by Exploiting Signal Transitions Phenomena
Authors: Mohammad Zavid Parvez, Manoranjan Paul
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A seizure prediction method is proposed by extracting global features using phase correlation between adjacent epochs for detecting relative changes and local features using fluctuation/deviation within an epoch for determining fine changes of different EEG signals. A classifier and a regularization technique are applied for the reduction of false alarms and improvement of the overall prediction accuracy. The experiments show that the proposed method outperforms the state-of-the-art methods and provides high prediction accuracy (i.e., 97.70%) with low false alarm using EEG signals in different brain locations from a benchmark data set.Keywords: Epilepsy, seizure, phase correlation, fluctuation, deviation.
Procedia PDF Downloads 4677548 Dripping Modes of Newtonian Liquids: The Effect of Nozzle Inclination
Authors: Amaraja Taur, Pankaj Doshi, Hak Koon Yeoh
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The dripping modes for a Newtonian liquid of viscosity µ emanating from an inclined nozzle at flow rate Q is investigated experimentally. As the liquid flow rate Q increases, starting with period-1 with satellite drops, the system transitions to period-1 dripping without satellite, then to limit cycle before showing chaotic responses. Phase diagrams shows the changes in the transitions between the different dripping modes for different nozzle inclination angle θ is constructed in the dimensionless (Q, µ) space.Keywords: dripping, inclined nozzle, phase diagram, satellite
Procedia PDF Downloads 2907547 Chemical and Physical Properties and Biocompatibility of Ti–6Al–4V Produced by Electron Beam Rapid Manufacturing and Selective Laser Melting for Biomedical Applications
Authors: Bing–Jing Zhao, Chang-Kui Liu, Hong Wang, Min Hu
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Electron beam rapid manufacturing (EBRM) or Selective laser melting is an additive manufacturing process that uses 3D CAD data as a digital information source and energy in the form of a high-power laser beam or electron beam to create three-dimensional metal parts by fusing fine metallic powders together.Object:The present study was conducted to evaluate the mechanical properties ,the phase transformation,the corrosivity and the biocompatibility of Ti-6Al-4V by EBRM,SLM and forging technique.Method: Ti-6Al-4V alloy standard test pieces were manufactured by EBRM, SLM and forging technique according to AMS4999,GB/T228 and ISO 10993.The mechanical properties were analyzed by universal test machine. The phase transformation was analyzed by X-ray diffraction and scanning electron microscopy. The corrosivity was analyzed by electrochemical method. The biocompatibility was analyzed by co-culturing with mesenchymal stem cell and analyzed by scanning electron microscopy (SEM) and alkaline phosphatase assay (ALP) to evaluate cell adhesion and differentiation, respectively. Results: The mechanical properties, the phase transformation, the corrosivity and the biocompatibility of Ti-6Al-4V by EBRM、SLM were similar to forging and meet the mechanical property requirements of AMS4999 standard. aphase microstructure for the EBM production contrast to the a’phase microstructure of the SLM product. Mesenchymal stem cell adhesion and differentiation were well. Conclusion: The property of the Ti-6Al-4V alloy manufactured by EBRM and SLM technique can meet the medical standard from this study. But some further study should be proceeded in order to applying well in clinical practice.Keywords: 3D printing, Electron Beam Rapid Manufacturing (EBRM), Selective Laser Melting (SLM), Computer Aided Design (CAD)
Procedia PDF Downloads 4557546 Control of Photovoltaic System Interfacing Grid
Authors: Zerzouri Nora
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In this paper, author presented the generalities of a photovoltaic system study and simulation. Author inserted the DC-DC converter to raise the voltage level and improve the operation of the PV panel by continuing the operating point at maximum power by using the Perturb and Observe technique (P&O). The connection to the network is made by inserting a three-phase voltage inverter allowing synchronization with the network the inverter is controlled by a PWM control. The simulation results allow the author to visualize the operation of the different components of the system, as well as the behavior of the system during the variation of meteorological values.Keywords: photovoltaic generator PV, boost converter, P&O MPPT, PWM inverter, three phase grid
Procedia PDF Downloads 1217545 Suitability of Alternative Insulating Fluid for Power Transformer: A Laboratory Investigation
Authors: S. N. Deepa, A. D. Srinivasan, K. T. Veeramanju, R. Sandeep Kumar, Ashwini Mathapati
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Power transformer is a vital element in a power system as it continuously regulates power flow, maintaining good voltage regulation. The working of transformer much depends on the oil insulation, the oil insulation also decides the aging of transformer and hence its reliability. The mineral oil based liquid insulation is globally accepted for power transformer insulation; however it is potentially hazardous due to its non-biodegradability. In this work efficient alternative biodegradable insulating fluid is presented as a replacement to conventional mineral oil. Dielectric tests are performed as distinct alternating fluid to evaluate the suitability for transformer insulation. The selection of the distinct natural esters for an insulation system is carried out by the laboratory investigation of Breakdown voltage, Oxidation stability, Dissipation factor, Permittivity, Viscosity, Flash and Fire point. It is proposed to study and characterize the properties of natural esters to be used in power transformer. Therefore for the investigation of the dielectric behavior rice bran oil, sesame oil, and sunflower oil are considered for the study. The investigated results have been compared with the mineral oil to validate the dielectric behavior of natural esters.Keywords: alternative insulating fluid, dielectric properties, natural esters, power transformers
Procedia PDF Downloads 1437544 Application of Lean Manufacturing Tools in Hot Asphalt Production
Authors: S. Bayona, J. Nunez, D. Paez, C. Diaz
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The application of Lean manufacturing tools continues to be an effective solution for increasing productivity, reducing costs and eliminating waste in the manufacture of goods and services. This article analyzes the production process of a hot asphalt manufacturing company from an administrative and technical perspective. Three main phases were analyzed, the first phase was related to the determination of the risk priority number of the main operations in asphalt mix production process by an FMEA (Failure Mode Effects Analysis), in the second phase the Value Stream Mapping (VSM) of the production line was performed and in the third phase a SWOT (Strengths, Weaknesses Opportunities, Threats) matrix was constructed. Among the most valued failure modes were the lack training of workers in occupational safety and health issues, the lack of signaling and classification of granulated material, and the overweight of vehicles loaded. The analysis of the results in the three phases agree on the importance of training operational workers, improve communication with external actors in order to minimize delays in material orders and strengthen control suppliers.Keywords: asphalt, lean manufacturing, productivity, process
Procedia PDF Downloads 1187543 Development of Stability Indicating Method and Characterization of Degradation Impurity of Nirmaltrelvir in Its Self-Emulsifying Drug Delivery System
Authors: Ravi Patel, Ravisinh Solanki, Dignesh Khunt
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A stability-indicating reverse phase high performance liquid chromatography (RP-HPLC) method was developed and validated for estimating Nirmatrelvir in its self-emulsifying drug delivery system (SEDDS). The separation of Nirmatrelvir and its degradation products was accomplished by employing an Agilent Zorbax Eclipse plus C18 (250 mm x 4.6 mm, 5 µm) column, through which the mobile phase 5 mM phosphate buffer (pH 4.0) as mobile phase A and Acetonitrile as mobile phase B in a ratio of (40:60 % v/v) was pumped at a flow rate of 1.0 mL/min, through the HPLC system. Chromatographic separation and elution were monitored by a photo-diode array detector at 210 nm. Stress studies have been employed to evaluate this method's ability to indicate stability. Nirmatrelvir was exposed to several stress conditions, such as acid, alkali, oxidative, photolytic, and thermal degradations. Significant degradation was observed during acid and alkali hydrolysis, and the resulting degradation product was successfully separated from the Nirmatrelvir peak, preventing any interference. Furthermore, the primary degradant produced under alkali degradation conditions was identified using UPLC-ESI-TQ-MS/MS. The method was validated in accordance with the International Council on Harmonization (ICH) and found to be selective, precise, accurate, linear, and robust. The apparent permeability of Nirmatrelvir SEDDS was 4.20 ± 0.21×10-6 cm/sec, and the average proportion of free drug recovered was 0.5%. The method developed in this study was feasible and accurate for routine quality control evaluation of Nirmatrelvir SEDDS.Keywords: Nirmatrelvir, SEDDS, degradation study, HPLC, LC-MS/MS
Procedia PDF Downloads 207542 Estimation and Validation of Free Lime Analysis of Clinker by Quantitative Phase Analysis Using X ray diffraction
Authors: Suresh Palla, Kalpna Sharma, Gaurav Bhatnagar, S. K. Chaturvedi, B. N. Mohapatra
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Determining the content of free lime is especially important to judge reactivity of the raw materials and clinker quality. The free lime limit isn’t the same for all cements; it depends on several factors, especially the temperature reached during the cooking and the grain size distribution in cement after grinding. Estimation of free lime by conventional method is influenced by the presence of portlandite and misleads the actual free lime content in the clinker for quality check up conditions. To ensure the product quality according to the standard specifications in terms of within the quality limits or not, a reliable, precise, and very reproducible method to quantify the relative phase abundances in the Portland Cement clinker and Portland Cements is to use X-ray diffraction (XRD) in combination with the Rietveld method. In the present study, a methodology was proposed using XRD to validate the obtained results of free lime by conventional method. The XRD and TG/DTA results confirm the presence of portlandite in the clinker to take the decision on the obtained free lime results through conventional method.Keywords: free lime, quantitative phase analysis, conventional method, x ray diffraction
Procedia PDF Downloads 1387541 Study of the Influence of Nozzle Length and Jet Angles on the Air Entrainment by Plunging Water Jets
Authors: José Luis Muñoz-Cobo González, Sergio Chiva Vicent, Khaled Harby Mohamed
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When a vertical liquid jet plunges into a liquid surface, after passing through a surrounding gas phase, it entrains a large amount of gas bubbles into the receiving pool, and it forms a large submerged two-phase region with a considerable interfacial area. At the intersection of the plunging jet and the liquid surface, free-surface instabilities are developed, and gas entrainment may be observed. If the jet impact velocity exceeds an inception velocity that is a function of the plunging flow conditions, the gas entrainment takes place. The general goal of this work is to study the effect of nozzle parameters (length-to-diameter ratio (lN/dN), jet angle (α) with the free water surface) and the jet operating conditions (initial jet diameters dN, initial jet velocity VN, and jet length x1) on the flow characteristics such as: inception velocity of the gas entrainment Ve, bubble penetration depth Hp, gas entrainment rate, Qa, centerline jet velocity Vc, and the axial jet velocity distribution Vx below the free water surface in a plunging liquid jet system.Keywords: inclined plunging water jets, entrainment, two phase flow, nozzle length
Procedia PDF Downloads 4697540 “Chasing Hope”: Parents’ Perspectives on Complementary and Alternative Interventions for Autism Spectrum Disorder Children in Kazakhstan
Authors: Sofiya An, Akbota Kanderzhanova, Assel Akhmetova, Faye Foster, Chee K. Chan
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Healthcare, education and social support for children with autism in Kazakhstan has been evolving and transforming over the last three decades. There is still limited knowledge of the use of complementary and alternative medicine by families caring for autistic children in this post-Soviet region. An exploratory qualitative focus group study of Kazakhstani families was carried out to capture and understand their experiences of using complementary and alternative (CAM) medicine. A total of six focus groups were conducted in five cities across the country including Nur-Sultan, Almaty, Kyzylorda, Karaganda and Taraz. The perceived factors driving the availability, choice, and use of complementary and alternative medicine by families of autistic children in the country were distilled and evaluated. The data collected was analyzed using a framework analysis and themes and subthemes were developed. Two major themes stood out. The first was the “unmet needs”, which relates to the predisposing factors that motivate parents to CAM uptake, and the second was the “chasing hope”, which relates to the enabling factors that facilitate parents’ uptake of CAM. Fear of missing out (FOMO) is a latent underlying motivation underscoring these two themes as well. Parents of autism spectrum disorder (ASD) children in Kazakhstan have to deal with many challenges when seeking treatment for their children with ASD. They are prepared and resort to try out whatever CAM interventions available. The motivation and rationale of choice of use is driven by the lack of options and the hope of any potential positive outcome rather than from rational decisions based on efficacy or the evidence-based data of CAM. Parents get desperate and are willing to try CAM regardless of and independent of their cultural and belief systems and they do not want to miss out just in case it might work. This study also gives an international and cross-cultural perspective on the motives, choice and practice of parents with ASD children using CAM in Kazakhstan, a Central Asian country.Keywords: autism spectrum disorder, Central Asia, complementary and alternative medicine, cross-cultural perspective, qualitative research
Procedia PDF Downloads 1467539 Development and Characterization of a Bio-Sourced Composite Material Based on Phase Change Material and Hemp Shives
Authors: Hachmi Toifane, Pierre Tittelein, Anh Dung Tran Le, Laurent Zalewsi
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This study introduces a composite material composed of bio-sourced phase-change material (PCM) of plant origin combined with hemp shives, developed in response to environmental challenges in the construction sector. The state of the art emphasizes the low thermal storage capacity of bio-based materials and highlights increasing need for developing sustainable materials that offer optimal thermal, mechanical, and hydric performances. The combining of PCM's thermal properties and hygric properties of hemp shives results in a material that combines lightness, strength, and hygrothermal regulation. Various formulations are being assessed and compared to conventional hemp concrete. Thermal characterization includes the measurements of thermal conductivity and numerical simulations to evaluate the thermal storage capacity. The results indicate that the addition of PCM significantly enhances the material's thermal storage capacity, positioning this one as a promising, eco-friendly solution for sustainable construction and for improving the energy efficiency of buildings.Keywords: hemp composite, bio-sourced phase change material, thermal storage, hemp shives
Procedia PDF Downloads 467538 Effect of Building Construction Sizes on Project Delivery Methods in Nigeria
Authors: Nuruddeen Usman, Mohammad Sani
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The performance of project delivery methods has been an issue of concern to various stakeholders in the construction industry. The contracting system of project delivery is the traditional system used in the delivery of most public projects in Nigeria. The direct labor system is used most times as an alternative to the traditional system. There were so many complain about the performance of contracting system and the suitability of direct labor as an alternative to the delivery of public projects. Therefore, this paper is aimed at investigating the effect of project size on the project delivery methods in the completed public buildings. Questionnaires were self-administered to managerial staff in the study area and analyzed using descriptive statistics. The findings reveals that contracting system was choosing for large size building construction project delivery with higher frequency (F) of 40 (76.9%) against direct labor with 12 (23.1%). While the small size project, the result revealed a frequency (F) of 26 (50%) for contracting system and direct labor system respectively. Base on the research findings, the contracting system, was recommended for all sizes of building construction project delivery while direct labor system can only use as an alternative for small size building construction projects delivery.Keywords: construction size, contracting system, direct labour, effect
Procedia PDF Downloads 4597537 Laboratory Measurement of Relative Permeability of Immiscible Fluids in Sand
Authors: Khwaja Naweed Seddiqi, Shigeo Honma
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Relative permeability is the important parameter controlling the immiscible displacement of multiphase fluids flow in porous medium. The relative permeability for immiscible displacement of two-phase fluids flow (oil and water) in porous medium has been measured in this paper. As a result of the experiment, irreducible water saturation, Swi, residual oil saturation, Sor, and relative permeability curves for Kerosene, Heavy oil and Lubricant oil were determined successfully.Keywords: relative permeability, two-phase flow, immiscible displacement, porous medium
Procedia PDF Downloads 3107536 Large Eddy Simulations for Flow Blurring Twin-Fluid Atomization Concept Using Volume of Fluid Method
Authors: Raju Murugan, Pankaj S. Kolhe
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The present study is mainly focusing on the numerical simulation of Flow Blurring (FB) twin fluid injection concept was proposed by Ganan-Calvo, which involves back flow atomization based on global bifurcation of liquid and gas streams, thus creating two-phase flow near the injector exit. The interesting feature of FB injector spray is an insignificant effect of variation in atomizing air to liquid ratio (ALR) on a spray cone angle. Besides, FB injectors produce a nearly uniform spatial distribution of mean droplet diameter and are least susceptible to variation in thermo-physical properties of fuels, making it a perfect candidate for fuel flexible combustor development. The FB injector working principle has been realized through experimental flow visualization techniques only. The present study explores potential of ANSYS Fluent based Large Eddy Simulation(LES) with volume of fluid (VOF) method to investigate two-phase flow just upstream of injector dump plane and spray quality immediate downstream of injector dump plane. Note that, water and air represent liquid and gas phase in all simulations and ALR is varied by changing the air mass flow rate alone. Preliminary results capture two phase flow just upstream of injector dump plane and qualitative agreement is observed with the available experimental literature.Keywords: flow blurring twin fluid atomization, large eddy simulation, volume of fluid, air to liquid ratio
Procedia PDF Downloads 2147535 Exploring Spiritual Needs of Taiwanese Inpatients with Advanced Cancer and Their Family Caregivers
Authors: Szu Mei Hsiao
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This study explores the spiritual needs of inpatients with advanced cancer and their family caregivers in one southern regional teaching hospital in Taiwan and elucidates the differences and similarities of spiritual needs between them. Little research reports the different phases of spiritual needs and the potential impact of Chinese cultural values on the spiritual needs. Qualitative inquiry was used. Twenty-one patients with advanced cancer and twenty-two family caregivers were recruited. During hospitalization, all participants identified spiritual needs both the palliative phase and the dying phase: (a) the need to foster faith/confidence and hope for medicine and/or God; (b) to understand the meaning and values of life; (c) to experience more reciprocal human love and forgiveness; and (d) to obey God’s/Heaven will. Furthermore, the differences of spiritual needs between patients with advanced cancer and their family caregivers are as follows: (a) family caregivers emphasized the need to inform relatives and say goodbye in order to die peacefully; (b) patients highlighted a need to maintain a certain physical appearance in order to preserve their dignity; nurture one’s willpower; learn about the experiences of cancer survivors; and identify one’s own life experience for understanding the meaning and values of life. Moreover, the dissimilarity of spiritual needs is that the patients pointed out the need to understand God’s will during the palliative treatment phase. However, the family caregivers identified the need to forgive each other, and inform relatives and say goodbye to patients in the dying phase. This research has shown that the needs of meaning/values of life and facing death peacefully are different between two groups. Health professionals will be encouraged to detect and to develop individualized care strategies to meet spiritual needs.Keywords: advanced cancer, Chinese culture, family caregivers, qualitative research, spiritual needs
Procedia PDF Downloads 3357534 Performance and Emission Characteristics of Spark Ignition Engine Running with Gasoline, Blends of Ethanol, and Blends of Ethiopian Arekie
Authors: Mengistu Gizaw Gawo, Bisrat Yoseph Gebrehiwot
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Petroleum fuels have become a threat to the world because of their toxic emissions. Besides, it is unknown how long they will last. The only known fact is that they are depleting rapidly and will not last long. So the world’s concern about finding environmentally friendly alternative fuels has increased recently. Hence alcohol fuels are found to be the most convenient alternatives to use in internal combustion engines. This research intends to introduce Ethiopian locally produced alcohol as an alternative in the blended form with gasoline to use in spark ignition engines. The traditionally distilled Arekie was purchased from a local producer and purified using fractional distillation. Then five Arekie-gasoline blends were prepared with the proportion of 5,10,15,20 and 25%v/v (A5, A10, A15, A20, and A25, respectively). Also, absolute ethanol was purchased from a local supplier, and ethanol-gasoline blends were prepared with a similar proportion as Arekie-gasoline blends (E5, E10, E15, E20, and E25). Then an experiment was conducted on a single-cylinder, 4-stroke, spark-ignition engine running at a constant speed of 2500 rpm and variable loads to investigate the performance and emission characteristics. Results showed that the performance and emission parameters are significantly improved as the ratio of Arekie and ethanol in gasoline increases at all loads. Among all tested fuels, E20 exhibited better performance, and E25 exhibited better emission. A20 provided a slightly lower performance than E20 but was much improved compared to pure gasoline. A25 provided comparable emissions with E25 and was much better than pure gasoline. Generally, adding up to 20%v/v Ethiopian Arekie in gasoline could make a better, renewable alternative to spark ignition engines.Keywords: alcohol fuels, alternative fuels, pollutant emissions, spark-ignition engine, Arekie-gasoline blends
Procedia PDF Downloads 1217533 Factors Associated with Weight Loss Maintenance after an Intervention Program
Authors: Filipa Cortez, Vanessa Pereira
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Introduction: The main challenge of obesity treatment is long-term weight loss maintenance. The 3 phases method is a weight loss program that combines a low carb and moderately high-protein diet, food supplements and a weekly one-to-one consultation with a certified nutritionist. Sustained weight control is the ultimate goal of phase 3. Success criterion was the minimum loss of 10% of initial weight and its maintenance after 12 months. Objective: The aim of this study was to identify factors associated with successful weight loss maintenance after 12 months at the end of 3 phases method. Methods: The study included 199 subjects that achieved their weight loss goal (phase 3). Weight and body mass index (BMI) were obtained at the baseline and every week until the end of the program. Therapeutic adherence was measured weekly on a Likert scale from 1 to 5. Subjects were considered in compliance with nutritional recommendation and supplementation when their classification was ≥ 4. After 12 months of the method, the current weight and number of previous weight-loss attempts were collected by telephone interview. The statistical significance was assumed at p-values < 0.05. Statistical analyses were performed using SPSS TM software v.21. Results: 65.3% of subjects met the success criterion. The factors which displayed a significant weight loss maintenance prediction were: greater initial percentage weight loss (OR=1.44) during the weight loss intervention and a higher number of consultations in phase 3 (OR=1.10). Conclusion: These findings suggest that the percentage weight loss during the weight loss intervention and the number of consultations in phase 3 may facilitate maintenance of weight loss after the 3 phases method.Keywords: obesity, weight maintenance, low-carbohydrate diet, dietary supplements
Procedia PDF Downloads 1517532 Effectiveness of Homoeopathic Medicine Conium Maculatum 200 C for Management of Pyuria
Authors: Amir Ashraf
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Homoeopathy is an alternative system of medicine discovered by German physician Samuel Hahnemann in 1796. It has been used by several people for various health conditions globally for more than last 200 years. In India, homoeopathy is considered as a major system of alternative medicine. Homoeopathy is found effective in various medical conditions including Pyuria. Pyuria is the condition in which pus cells are found in urine. Homoeopathy is very useful for reducing pus cells, and homeopathically potentized Conium Mac (Hemlock) is an important remedy commonly used for reducing pyuria. Aim: To reduce the amount pus cells found in urine using Conium Mac 200C. Methods: Design. Small N Design. Samples: Purposive Sampling with 5 cases diagnosed as pyuria. Tools: Personal Data Schedule and ICD-10 Criteria for Pyuria. Techniques: Potentized homoeopathic medicine, Conium Mac 200th potency is used. Statistical Analysis: The statistical analyses were done using non-parametric tests. Results: There is significant pre/post difference has been identified. Conclusion: Homoeopathic potency, Conium Mac 200 C is effective in reducing the increased level of pus cells found in urine samples.Keywords: homoeopathy, alternative medicine, Pyuria, Conim Mac, small N design, non-parametric tests, homeopathic physician, Ashirvad Hospital, Kannur
Procedia PDF Downloads 336