Search results for: liquid smoke
1164 Gas Pressure Evaluation through Radial Velocity Measurement of Fluid Flow Modeled by Drift Flux Model
Authors: Aicha Rima Cheniti, Hatem Besbes, Joseph Haggege, Christophe Sintes
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In this paper, we consider a drift flux mixture model of the blood flow. The mixture consists of gas phase which is carbon dioxide and liquid phase which is an aqueous carbon dioxide solution. This model was used to determine the distributions of the mixture velocity, the mixture pressure, and the carbon dioxide pressure. These theoretical data are used to determine a measurement method of mean gas pressure through the determination of radial velocity distribution. This method can be applicable in experimental domain.Keywords: mean carbon dioxide pressure, mean mixture pressure, mixture velocity, radial velocity
Procedia PDF Downloads 3241163 Prevalence of Common Mental Disorders and Its Correlation with Mental Toughness among Professional South African Rugby Players
Authors: H. B. Grobler, K. Du Plooy, P. Kruger, S. Ellis
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Objectives: The primary objective of the study was to determine the common mental disorders (CMD) identified by professional South African rugby players and its correlation with their mental toughness, as a first step towards developing such a programme within a larger research project. Design: Survey research, within the theoretical perspective of field theory, was conducted, utilising an adaptation of an already existing mental health questionnaire. The aim was to obtain feedback from as many possible professional South African rugby players in order to make certain generalizations and come to conclusions with regard to the current mental health experiences of these rugby players. Methods: Non-randomized sampling was done, linking it with internet research in the form of the online completion of a questionnaire. A sample of 215 rugby players participated and completed the online questionnaire. Permission was obtained to make use of an existing questionnaire, previously used by the specific authors with retired professional rugby players. A section on mental toughness was added. Data were descriptively analysed by means of the SPSS software platform. Results: Results indicated that the most significant problem that the players are experiencing, is a problem with alcohol (47.9%). Other problems that featured are distress (16.3%), sleep disturbances (7%), as well as anxiety and depression (4.2%). 4.7% of the players indicated that they smoke. 3.3% of the players experience themselves as not being mentally tough. A positive correlation between mental toughness and sound sleep (0.262) was found while a negative correlation was found between mental toughness and the following: anxiety/depression (-0.401), anxiety/depression positive (-0.423), distress (-0.259) and common mental disorder problems in general (-0.220). Conclusions: Although the presence of CMD at first glance do not seem significantly high amongst all the players, it must be considered that if one player in a team experiences the presence of CMD, it will have an impact on his mental toughness and most likely on his performance, as well as on the performance of the whole team. It is therefore important to ensure mental health in the whole team, by addressing individual CMD problems. A mental health support programme is therefore needed to be implemented to the benefit of these players within the South African context.Keywords: common mental disorders, mental toughness, professional athletes, rugby players
Procedia PDF Downloads 2181162 Antimicrobial and Antioxidant Activities of Actinobacteria Isolated from the Pollen of Pinus sylvestris Grown on the Lake Baikal Shore
Authors: Denis V. Axenov-Gribanov, Irina V. Voytsekhovskaya, Evgenii S. Protasov, Maxim A. Timofeyev
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Isolated ecosystems existing under specific environmental conditions have been shown to be promising sources of new strains of actinobacteria. The taiga forest of Baikal Siberia has not been well studied, and its actinobacterial population remains uncharacterized. The proximity between the huge water mass of Lake Baikal and high mountain ranges influences the structure and diversity of the plant world in Siberia. Here, we report the isolation of eighteen actinobacterial strains from male cones of Pinus sylvestris trees growing on the shore of the ancient Lake Baikal in Siberia. The actinobacterial strains were isolated on solid nutrient MS media and Czapek agar supplemented with cycloheximide and phosphomycin. Identification of actinobacteria was carried out by 16S rRNA gene sequencing and further analysis of the evolutionary history. Four different liquid and solid media (NL19, DNPM, SG and ISP) were tested for metabolite production. The metabolite extracts produced by the isolated strains were tested for antibacterial and antifungal activities. Also, antiradical activity of crude extracts was carried out. Strain Streptomyces sp. IB 2014 I 74-3 that active against Gram-negative bacteria was selected for dereplication analysis with using the high-yield liquid chromatography with mass-spectrometry. Mass detection was performed in both positive and negative modes, with the detection range set to 160–2500 m/z. Data were collected and analyzed using Bruker Compass Data Analysis software, version 4.1. Dereplication was performed using the Dictionary of Natural Products (DNP) database version 6.1 with the following search parameters: accurate molecular mass, absorption spectra and source of compound isolation. Thus, in addition to more common representative strains of Streptomyces, several species belonging to the genera Rhodococcus, Amycolatopsis, and Micromonospora were isolated. Several of the selected strains were deposited in the Russian Collection of Agricultural Microorganisms (RCAM), St. Petersburg, Russia. All isolated strains exhibited antibacterial and antifungal activities. We identified several strains that inhibited the growth of the pathogen Candida albicans but did not hinder the growth of Saccharomyces cerevisiae. Several isolates were active against Gram-positive and Gram-negative bacteria. Moreover, extracts of several strains demonstrated high antioxidant activity. The high proportion of biologically active strains producing antibacterial and specific antifungal compounds may reflect their role in protecting pollen against phytopathogens. Dereplication of the secondary metabolites of the strain Streptomyces sp. IB 2014 I 74-3 was resulted in the fact that a total of 59 major compounds were detected in the culture liquid extract of strain cultivated in ISP medium. Eight compounds were preliminarily identified based on characteristics described in the Dictionary of Natural Products database, using the search parameters Streptomyces sp. IB 2014 I 74-3 was found to produce saframycin A, Y3 and S; 2-amino-3-oxo-3H-phenoxazine-1,8-dicarboxylic acid; galtamycinone; platencin A4-13R and A4-4S; ganefromycin d1; the antibiotic SS 8201B; and streptothricin D, 40-decarbamoyl, 60-carbamoyl. Moreover, forty-nine of the 59 compounds detected in the extract examined in the present study did not result in any positive hits when searching within the DNP database and could not be identified based on available mass-spec data. Thus, these compounds might represent new findings.Keywords: actinobacteria, Baikal Lake, biodiversity, male cones, Pinus sylvestris
Procedia PDF Downloads 2321161 The Next Generation Neutrinoless Double-Beta Decay Experiment nEXO
Authors: Ryan Maclellan
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The nEXO Collaboration is designing a very large detector for neutrinoless double beta decay of Xe-136. The nEXO detector is rooted in the current EXO-200 program, which has reached a sensitivity for the half-life of the decay of 1.9x10^25 years with an exposure of 99.8 kg-y. The baseline nEXO design assumes 5 tonnes of liquid xenon, enriched in the mass 136 isotope, within a time projection chamber. The detector is being designed to reach a half-life sensitivity of > 5x10^27 years covering the inverted neutrino mass hierarchy, with 5 years of data. We present the nEXO detector design, the current status of R&D efforts, and the physics case for the experiment.Keywords: double-beta, Majorana, neutrino, neutrinoless
Procedia PDF Downloads 4231160 Determination of Antioxidant Activities of Sumac (Rhus Coriaria) Extracts with Different Solvents
Authors: F. T. Senberber, N. Tugrul, E. Moroydor Derun
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As a nutraceutical, sumac (Rhus Coriaria) was extracted by using different solvents of methanol, ethanol, and water. The DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) method of free radical scavenging capacity was used to determine the effects of solvent on antioxidant activities of the plant. The total phenolic content was studied by The Folin Ciocalteu Reagent method. The antioxidant activities of extracts exhibit minor changes in different solvents and varied in the range of 84.3–86.4 %. The total phenolic contents are affected by the selected solvent. The highest total phenolic content was determined at the liquid phase of water and it was estimated as 26.3 mg/g in gallic acid.Keywords: DPPH, solvent, sumac, total phenolic content
Procedia PDF Downloads 1531159 Reducing Tobacco Consumption in a Rural Village of Sri Lanka Though a Community Based Health Promotion Intervention
Authors: B. A. N. Madubashini, S. Anojan, S. Thurka, N. M. C. J. Nawasinghe, G. A. S. Milanga, W. M. I. S. Weerakoon, I. D. N. Ihalahewage
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Evidence-based health promotional approaches are known to be successful ways of reducing tobacco consumption in a rural village. Hence tobacco prevention is essential in improving lives of people, and community-based approaches are considered as effective. This community-based health promotion intervention implemented to reduce high consumption of tobacco in a rural area in Sri Lanka. This intervention was conducted in a rural village of Sri Lanka. In the beginning, facilitation discussions conducted with community members to identify determinants leading to tobacco consumption among villagers. Intervention was planed based on those determinants. Community actions through small active groups to demote smoking were generated. Children groups displayed cigarette buds collected around common places such as temple to community gatherings including funeral welfare society elaborating the cost and the money spent on cigarettes. A till (expenditure box) was introduced, and smokers in family were encouraged to put money on a cigarette to it when they decide to smoke instead. This way they could monitor potential savings if quit. Children groups introduced a tool 'Engalanthe puthata (for overseas son)' to shops. Shop owners agreed to add a pebble to a box whenever they sell a cigarette. The money spent on cigarettes in that shop was calculated regularly, and that was considered as money sent to tobacco company overseas, so to the son of the company owner. This was useful to encourage quitting and to stop selling cigarette in the shops. All four shops in the community volunteered to stop selling cigarettes. Eleven percent of users quitted smoking and 37% users reduced smoking. Child empowerment was high, and 60% of children had shown their disapproval on smoking publicly at least once. Similar community-based health promotion intervention can be used to generate community actions leading to reduction of tobacco consumption.Keywords: cigarette, community, empowerment, health promotion, intervention
Procedia PDF Downloads 2291158 The Impact of Trading Switch on Price and Liquidity
Authors: Bel Abed Ines Mariem
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Different stock markets keep changing their exchange structure for the only purpose of improving the functioning of their markets. This paper investigates the effects of the transfer from one trading category to another in the Tunisian Stock Exchange on market price and liquidity. The sample consists of 40 securities transferred from call auction to continuous auction and conversely during the period between 2004 and 2013. The methodology used is the event study. Empirical results show an interesting phenomenon observed; stocks transferred to the call system have experienced an improvement on their price and liquidity especially for less liquid ones. However, price and liquidity for stocks transferred from call system to continuous system have decreased.Keywords: microstructure, call auction, continuous auction, price, liquidity and event study
Procedia PDF Downloads 3881157 Physico-Chemical Properties of Silurian Hot Shale in Ahnet Basin, Algeria: Case Study Well ASS-1
Authors: Mohamed Mehdi Kadri
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The prediction of hot shale interval in Silurian formation in a well drilled vertically in Ahnet basin Is by logging Data (Resistivity, Gamma Ray, Sonic) with the calculation of total organic carbon (TOC) using ∆ log R Method. The aim of this paper is to present Physico-chemical Properties of Hot Shale using IR spectroscopy and gas chromatography-mass spectrometry analysis; this mixture of measurements, evaluation and characterization show that the hot shale interval located in the lower of Silurian, the molecules adsorbed at the surface of shale sheet are significantly different from petroleum hydrocarbons this result are also supported with gas-liquid chromatography showed that the study extract is a hydroxypropyl.Keywords: physic-chemical analysis, reservoirs characterization, sweet window evaluation, Silurian shale, Ahnet basin
Procedia PDF Downloads 991156 Currently Use Pesticides: Fate, Availability, and Effects in Soils
Authors: Lucie Bielská, Lucia Škulcová, Martina Hvězdová, Jakub Hofman, Zdeněk Šimek
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The currently used pesticides represent a broad group of chemicals with various physicochemical and environmental properties which input has reached 2×106 tons/year and is expected to even increases. From that amount, only 1% directly interacts with the target organism while the rest represents a potential risk to the environment and human health. Despite being authorized and approved for field applications, the effects of pesticides in the environment can differ from the model scenarios due to the various pesticide-soil interactions and resulting modified fate and behavior. As such, a direct monitoring of pesticide residues and evaluation of their impact on soil biota, aquatic environment, food contamination, and human health should be performed to prevent environmental and economic damages. The present project focuses on fluvisols as they are intensively used in the agriculture but face to several environmental stressors. Fluvisols develop in the vicinity of rivers by the periodic settling of alluvial sediments and periodic interruptions to pedogenesis by flooding. As a result, fluvisols exhibit very high yields per area unit, are intensively used and loaded by pesticides. Regarding the floods, their regular contacts with surface water arise from serious concerns about the surface water contamination. In order to monitor pesticide residues and assess their environmental and biological impact within this project, 70 fluvisols were sampled over the Czech Republic and analyzed for the total and bioaccessible amounts of 40 various pesticides. For that purpose, methodologies for the pesticide extraction and analysis with liquid chromatography-mass spectrometry technique were developed and optimized. To assess the biological risks, both the earthworm bioaccumulation tests and various types of passive sampling techniques (XAD resin, Chemcatcher, and silicon rubber) were optimized and applied. These data on chemical analysis and bioavailability were combined with the results of soil analysis, including the measurement of basic physicochemical soil properties as well detailed characterization of soil organic matter with the advanced method of diffuse reflectance infrared spectrometry. The results provide unique data on the residual levels of pesticides in the Czech Republic and on the factors responsible for increased pesticide residue levels that should be included in the modeling of pesticide fate and effects.Keywords: currently used pesticides, fluvisoils, bioavailability, Quechers, liquid-chromatography-mass spectrometry, soil properties, DRIFT analysis, pesticides
Procedia PDF Downloads 4631155 Development and Evaluation of Simvastatin Based Self Nanoemulsifying Drug Delivery System (SNEDDS) for Treatment of Alzheimer's Disease
Authors: Hardeep
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The aim of this research work to improve the solubility and bioavailability of Simvastatin using a self nanoemulsifying drug delivery system (SNEDDS). Self emulsifying property of various oils including essential oils was evaluated with suitable surfactants and co-surfactants. Validation of a method for accuracy, repeatability, Interday and intraday precision, ruggedness, and robustness were within acceptable limits. The liquid SNEDDS was prepared and optimized using a ternary phase diagram, thermodynamic, centrifugation and cloud point studies. The globule size of optimized formulations was less than 200 nm which could be an acceptable nanoemulsion size range. The mean droplet size, drug loading, PDI and zeta potential were found to be 141.0 nm, 92.22%, 0.23 and -10.13 mV and 153.5nm, 93.89 % ,0.41 and -11.7 mV and 164.26 nm, 95.26% , 0.41 and -10.66mV respectively.Keywords: simvastatin, self nanoemulsifying drug delivery system, solubility, bioavailability
Procedia PDF Downloads 2011154 Experimental Study on Granulated Steel Slag as an Alternative to River Sand
Authors: K. Raghu, M. N. Vathhsala, Naveen Aradya, Sharth
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River sand is the most preferred fine aggregate for mortar and concrete. River sand is a product of natural weathering of rocks over a period of millions of years and is mined from river beds. Sand mining has disastrous environmental consequences. The excessive mining of river bed is creating an ecological imbalance. This has lead to have restrictions imposed by ministry of environment on sand mining. Driven by the acute need for sand, stone dust or manufactured sand prepared from the crushing and screening of coarse aggregate is being used as sand in the recent past. However manufactured sand is also a natural material and has quarrying and quality issues. To reduce the burden on the environment, alternative materials to be used as fine aggregates are being extensively investigated all over the world. Looking to the quantum of requirements, quality and properties there has been a global consensus on a material – Granulated slags. Granulated slag has been proven as a suitable material for replacing natural sand / crushed fine aggregates. In developed countries, the use of granulated slag as fine aggregate to replace natural sand is well established and is in regular practice. In the present paper Granulated slag has been experimented for usage in mortar. Slags are the main by-products generated during iron and steel production in the steel industry. Over the past decades, the steel production has increased and, consequently, the higher volumes of by-products and residues generated which have driven to the reuse of these materials in an increasingly efficient way. In recent years new technologies have been developed to improve the recovery rates of slags. Increase of slags recovery and use in different fields of applications like cement making, construction and fertilizers help in preserving natural resources. In addition to the environment protection, these practices produced economic benefits, by providing sustainable solutions that can allow the steel industry to achieve its ambitious targets of “zero waste” in coming years. Slags are generated at two different stages of steel production, iron making and steel making known as BF(Blast Furnace) slag and steel slag respectively. The slagging agent or fluxes, such as lime stone, dolomite and quartzite added into BF or steel making furnaces in order to remove impurities from ore, scrap and other ferrous charges during smelting. The slag formation is the result of a complex series of physical and chemical reactions between the non-metallic charge(lime stone, dolomite, fluxes), the energy sources(coal, coke, oxygen, etc.) and refractory materials. Because of the high temperatures (about 15000 C) during their generation, slags do not contain any organic substances. Due to the fact that slags are lighter than the liquid metal, they float and get easily removed. The slags protect the metal bath from atmosphere and maintain temperature through a kind of liquid formation. These slags are in liquid state and solidified in air after dumping in the pit or granulated by impinging water systems. Generally, BF slags are granulated and used in cement making due to its high cementious properties, and steel slags are mostly dumped due to unfavourable physio-chemical conditions. The increasing dump of steel slag not only occupies a plenty of land but also wastes resources and can potentially have an impact on the environment due to water pollution. Since BF slag contains little Fe and can be used directly. BF slag has found a wide application, such as cement production, road construction, Civil Engineering work, fertilizer production, landfill daily cover, soil reclamation, prior to its application outside the iron and steel making process.Keywords: steel slag, river sand, granulated slag, environmental
Procedia PDF Downloads 2441153 Compressed Natural Gas (CNG) Injector Research for Dual Fuel Engine
Authors: Adam Majczak, Grzegorz Barański, Marcin Szlachetka
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Environmental considerations necessitate the search for new energy sources. One of the available solutions is a partial replacement of diesel fuel by compressed natural gas (CNG) in the compression ignition engines. This type of the engines is used mainly in vans and trucks. These units are also gaining more and more popularity in the passenger car market. In Europe, this part of the market share reaches 50%. Diesel engines are also used in industry in such vehicles as ship or locomotives. Diesel engines have higher emissions of nitrogen oxides in comparison to spark ignition engines. This can be currently limited by optimizing the combustion process and the use of additional systems such as exhaust gas recirculation or AdBlue technology. As a result of the combustion process of diesel fuel also particulate matter (PM) that are harmful to the human health are emitted. Their emission is limited by the use of a particulate filter. One of the method for toxic components emission reduction may be the use of liquid gas fuel such as propane and butane (LPG) or compressed natural gas (CNG). In addition to the environmental aspects, there are also economic reasons for the use of gaseous fuels to power diesel engines. A total or partial replacement of diesel gas is possible. Depending on the used technology and the percentage of diesel fuel replacement, it is possible to reduce the content of nitrogen oxides in the exhaust gas even by 30%, particulate matter (PM) by 95 % carbon monoxide and by 20%, in relation to original diesel fuel. The research object is prototype gas injector designed for direct injection of compressed natural gas (CNG) in compression ignition engines. The construction of the injector allows for it positioning in the glow plug socket, so that the gas is injected directly into the combustion chamber. The cycle analysis of the four-cylinder Andoria ADCR engine with a capacity of 2.6 dm3 for different crankshaft rotational speeds allowed to determine the necessary time for fuel injection. Because of that, it was possible to determine the required mass flow rate of the injector, for replacing as much of the original fuel by gaseous fuel. To ensure a high value of flow inside the injector, supply pressure equal to 1 MPa was applied. High gas supply pressure requires high value of valve opening forces. For this purpose, an injector with hydraulic control system, using a liquid under pressure for the opening process was designed. On the basis of air pressure measurements in the flow line after the injector, the analysis of opening and closing of the valve was made. Measurements of outflow mass of the injector were also carried out. The results showed that the designed injector meets the requirements necessary to supply ADCR engine by the CNG fuel.Keywords: CNG, diesel engine, gas flow, gas injector
Procedia PDF Downloads 4931152 Inertial Spreading of Drop on Porous Surfaces
Authors: Shilpa Sahoo, Michel Louge, Anthony Reeves, Olivier Desjardins, Susan Daniel, Sadik Omowunmi
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The microgravity on the International Space Station (ISS) was exploited to study the imbibition of water into a network of hydrophilic cylindrical capillaries on time and length scales long enough to observe details hitherto inaccessible under Earth gravity. When a drop touches a porous medium, it spreads as if laid on a composite surface. The surface first behaves as a hydrophobic material, as liquid must penetrate pores filled with air. When contact is established, some of the liquid is drawn into pores by a capillarity that is resisted by viscous forces growing with length of the imbibed region. This process always begins with an inertial regime that is complicated by possible contact pinning. To study imbibition on Earth, time and distance must be shrunk to mitigate gravity-induced distortion. These small scales make it impossible to observe the inertial and pinning processes in detail. Instead, in the International Space Station (ISS), astronaut Luca Parmitano slowly extruded water spheres until they touched any of nine capillary plates. The 12mm diameter droplets were large enough for high-speed GX1050C video cameras on top and side to visualize details near individual capillaries, and long enough to observe dynamics of the entire imbibition process. To investigate the role of contact pinning, a text matrix was produced which consisted nine kinds of porous capillary plates made of gold-coated brass treated with Self-Assembled Monolayers (SAM) that fixed advancing and receding contact angles to known values. In the ISS, long-term microgravity allowed unambiguous observations of the role of contact line pinning during the inertial phase of imbibition. The high-speed videos of spreading and imbibition on the porous plates were analyzed using computer vision software to calculate the radius of the droplet contact patch with the plate and height of the droplet vs time. These observations are compared with numerical simulations and with data that we obtained at the ESA ZARM free-fall tower in Bremen with a unique mechanism producing relatively large water spheres and similarity in the results were observed. The data obtained from the ISS can be used as a benchmark for further numerical simulations in the field.Keywords: droplet imbibition, hydrophilic surface, inertial phase, porous medium
Procedia PDF Downloads 1391151 Electrodeposition of Silicon Nanoparticles Using Ionic Liquid for Energy Storage Application
Authors: Anjali Vanpariya, Priyanka Marathey, Sakshum Khanna, Roma Patel, Indrajit Mukhopadhyay
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Silicon (Si) is a promising negative electrode material for lithium-ion batteries (LiBs) due to its low cost, non-toxicity, and a high theoretical capacity of 4200 mAhg⁻¹. The primary challenge of the application of Si-based LiBs is large volume expansion (~ 300%) during the charge-discharge process. Incorporation of graphene, carbon nanotubes (CNTs), morphological control, and nanoparticles was utilized as effective strategies to tackle volume expansion issues. However, molten salt methods can resolve the issue, but high-temperature requirement limits its application. For sustainable and practical approach, room temperature (RT) based methods are essentially required. Use of ionic liquids (ILs) for electrodeposition of Si nanostructures can possibly resolve the issue of temperature as well as greener media. In this work, electrodeposition of Si nanoparticles on gold substrate was successfully carried out in the presence of ILs media, 1-butyl-3-methylimidazolium-bis (trifluoromethyl sulfonyl) imide (BMImTf₂N) at room temperature. Cyclic voltammetry (CV) suggests the sequential reduction of Si⁴⁺ to Si²⁺ and then Si nanoparticles (SiNs). The structure and morphology of the electrodeposited SiNs were investigated by FE-SEM and observed interconnected Si nanoparticles of average particle size ⁓100-200 nm. XRD and XPS data confirm the deposition of Si on Au (111). The first discharge-charge capacity of Si anode material has been found to be 1857 and 422 mAhg⁻¹, respectively, at current density 7.8 Ag⁻¹. The irreversible capacity of the first discharge-charge process can be attributed to the solid electrolyte interface (SEI) formation via electrolyte decomposition, and trapped Li⁺ inserted into the inner pores of Si. Pulverization of SiNs results in the creation of a new active site, which facilitates the formation of new SEI in the subsequent cycles leading to fading in a specific capacity. After 20 cycles, charge-discharge profiles have been stabilized, and a reversible capacity of 150 mAhg⁻¹ is retained. Electrochemical impedance spectroscopy (EIS) data shows the decrease in Rct value from 94.7 to 47.6 kΩ after 50 cycles of charge-discharge, which demonstrates the improvements of the interfacial charge transfer kinetics. The decrease in the Warburg impedance after 50 cycles of charge-discharge measurements indicates facile diffusion in fragmented and smaller Si nanoparticles. In summary, Si nanoparticles deposited on gold substrate using ILs as media and characterized well with different analytical techniques. Synthesized material was successfully utilized for LiBs application, which is well supported by CV and EIS data.Keywords: silicon nanoparticles, ionic liquid, electrodeposition, cyclic voltammetry, Li-ion battery
Procedia PDF Downloads 1251150 A Parallel Computation Based on GPU Programming for a 3D Compressible Fluid Flow Simulation
Authors: Sugeng Rianto, P.W. Arinto Yudi, Soemarno Muhammad Nurhuda
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A computation of a 3D compressible fluid flow for virtual environment with haptic interaction can be a non-trivial issue. This is especially how to reach good performances and balancing between visualization, tactile feedback interaction, and computations. In this paper, we describe our approach of computation methods based on parallel programming on a GPU. The 3D fluid flow solvers have been developed for smoke dispersion simulation by using combinations of the cubic interpolated propagation (CIP) based fluid flow solvers and the advantages of the parallelism and programmability of the GPU. The fluid flow solver is generated in the GPU-CPU message passing scheme to get rapid development of haptic feedback modes for fluid dynamic data. A rapid solution in fluid flow solvers is developed by applying cubic interpolated propagation (CIP) fluid flow solvers. From this scheme, multiphase fluid flow equations can be solved simultaneously. To get more acceleration in the computation, the Navier-Stoke Equations (NSEs) is packed into channels of texel, where computation models are performed on pixels that can be considered to be a grid of cells. Therefore, despite of the complexity of the obstacle geometry, processing on multiple vertices and pixels can be done simultaneously in parallel. The data are also shared in global memory for CPU to control the haptic in providing kinaesthetic interaction and felling. The results show that GPU based parallel computation approaches provide effective simulation of compressible fluid flow model for real-time interaction in 3D computer graphic for PC platform. This report has shown the feasibility of a new approach of solving the compressible fluid flow equations on the GPU. The experimental tests proved that the compressible fluid flowing on various obstacles with haptic interactions on the few model obstacles can be effectively and efficiently simulated on the reasonable frame rate with a realistic visualization. These results confirm that good performances and balancing between visualization, tactile feedback interaction, and computations can be applied successfully.Keywords: CIP, compressible fluid, GPU programming, parallel computation, real-time visualisation
Procedia PDF Downloads 4321149 An Approach to Study the Biodegradation of Low Density Polyethylene Using Microbial Strains of Bacillus subtilus, Aspergillus niger, Pseudomonas fluroscence in Different Media Form and Salt Condition
Authors: Monu Ojha, Rahul Rana, Satywati Sharma, Kavya Dashora
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The global production rate of plastics has increased enormously and global demand for polyethylene resins –High-density polyethylene (HDPE), Linear low-density polyethylene (LLDPE) and Low-density polyethylene (LDPE) is expected to rise drastically, with very high value. These get accumulated in the environment, posing a potential ecological threat as they are degrading at a very slow rate and remain in the environment indefinitely. The aim of the present study was to investigate the potential of commonly found soil microbes like Bacillus subtilus, Aspergillus niger, Pseudomonas fluroscence for their ability to biodegrade LDPE in the lab on solid and liquid media conditions as well as in presence of 1% salt in the soil. This study was conducted at Indian Institute of Technology, Delhi, India from July to September where average temperature and RH (Relative Humidity) were 33 degrees Celcius and 80% respectively. It revealed that the weight loss of LDPE strip obtained from market of approximately 4x6 cm dimensions is more in liquid broth media than in solid agar media. The percentage weight loss by P. fluroscence, A. niger and B. subtilus observed after 80 days of incubation was 15.52, 9.24 and 8.99% respectively in broth media and 6.93, 2.18 and 4.76 % in agar media. The LDPE strips from same source and on the same were subjected to soil in presence of above microbes with 1% salt (NaCl: obtained from commercial table salt) with temperature and RH 33 degree Celcius and 80%. It was found that the rate of degradation increased in the soil than under lab conditions. The rate of weight loss of LDPE strips under same conditions given in lab was found to be 32.98, 15.01 and17.09 % by P. fluroscence, A. niger and B. subtilus respectively. The breaking strength was found to be 9.65N, 29N and 23.85 N for P. fluroscence, A. niger and B. subtilus respectively. SEM analysis conducted on Zeiss EVO 50 confirmed that surface of LDPE becomes physically weak after biological treatment. There was the increase in the surface roughness indicating Surface erosion of LDPE film. FTIR (Fourier-transform infrared spectroscopy) analysis of the degraded LDPE films showed stretching of aldehyde group at 3334.92 and 3228.84 cm-1,, C–C=C symmetric of aromatic ring at 1639.49 cm-1.There was also C=O stretching of aldehyde group at 1735.93 cm-1. N=O peak bend was also observed which corresponds to 1365.60 cm-1, C–O stretching of ether group at 1217.08 and 1078.21 cm-1.Keywords: microbial degradation, LDPE, Aspergillus niger, Bacillus subtilus, Peudomonas fluroscence, common salt
Procedia PDF Downloads 1651148 Stability and Rheology of Sodium Diclofenac-Loaded and Unloaded Palm Kernel Oil Esters Nanoemulsion Systems
Authors: Malahat Rezaee, Mahiran Basri, Raja Noor Zaliha Raja Abdul Rahman, Abu Bakar Salleh
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Sodium diclofenac is one of the most commonly used drugs of nonsteroidal anti-inflammatory drugs (NSAIDs). It is especially effective in the controlling the severe conditions of inflammation and pain, musculoskeletal disorders, arthritis, and dysmenorrhea. Formulation as nanoemulsions is one of the nanoscience approaches that have been progressively considered in pharmaceutical science for transdermal delivery of drug. Nanoemulsions are a type of emulsion with particle sizes ranging from 20 nm to 200 nm. An emulsion is formed by the dispersion of one liquid, usually the oil phase in another immiscible liquid, water phase that is stabilized using surfactant. Palm kernel oil esters (PKOEs), in comparison to other oils; contain higher amounts of shorter chain esters, which suitable to be applied in micro and nanoemulsion systems as a carrier for actives, with excellent wetting behavior without the oily feeling. This research was aimed to study the effect of O/S ratio on stability and rheological behavior of sodium diclofenac loaded and unloaded palm kernel oil esters nanoemulsion systems. The effect of different O/S ratio of 0.25, 0.50, 0.75, 1.00 and 1.25 on stability of the drug-loaded and unloaded nanoemulsion formulations was evaluated by centrifugation, freeze-thaw cycle and storage stability tests. Lecithin and cremophor EL were used as surfactant. The stability of the prepared nanoemulsion formulations was assessed based on the change in zeta potential and droplet size as a function of time. Instability mechanisms including coalescence and Ostwald ripening for the nanoemulsion system were discussed. In comparison between drug-loaded and unloaded nanoemulsion formulations, drug-loaded formulations represented smaller particle size and higher stability. In addition, the O/S ratio of 0.5 was found to be the best ratio of oil and surfactant for production of a nanoemulsion with the highest stability. The effect of O/S ratio on rheological properties of drug-loaded and unloaded nanoemulsion systems was studied by plotting the flow curves of shear stress (τ) and viscosity (η) as a function of shear rate (γ). The data were fitted to the Power Law model. The results showed that all nanoemulsion formulations exhibited non-Newtonian flow behaviour by displaying shear thinning behaviour. Viscosity and yield stress were also evaluated. The nanoemulsion formulation with the O/S ratio of 0.5 represented higher viscosity and K values. In addition, the sodium diclofenac loaded formulations had more viscosity and higher yield stress than drug-unloaded formulations.Keywords: nanoemulsions, palm kernel oil esters, sodium diclofenac, rheoligy, stability
Procedia PDF Downloads 4231147 Two and Three Layer Lamination of Nanofiber
Authors: Roman Knizek, Denisa Karhankova, Ludmila Fridrichova
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For their exceptional properties nanofibers, respectively, nanofiber layers are achieving an increasingly wider range of uses. Nowadays nanofibers are used mainly in the field of air filtration where they are removing submicron particles, bacteria, and viruses. Their efficiency is not changed in time, and the power consumption is much lower than that of electrically charged filters. Nanofibers are primarily used for converting and storage of energy in both air and liquid filtration, in food and packaging, protecting the environment, but also in health care which is made possible by their newly discovered properties. However, a major problem of the nanofiber layer is practically zero abrasion resistance; it is, therefore, necessary to laminate the nanofiber layer with another suitable material. Unfortunately, lamination of nanofiber layers is a major problem since the nanofiber layer contains small pores through which it is very difficult for adhesion to pass through. Therefore, there is still only a small percentage of products with these unique fibers 5.Keywords: nanofiber layer, nanomembrane, lamination, electrospinning
Procedia PDF Downloads 7271146 The Use of the Matlab Software as the Best Way to Recognize Penumbra Region in Radiotherapy
Authors: Alireza Shayegan, Morteza Amirabadi
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The y tool was developed to quantitatively compare dose distributions, either measured or calculated. Before computing ɣ, the dose and distance scales of the two distributions, referred to as evaluated and reference, are re-normalized by dose and distance criteria, respectively. The re-normalization allows the dose distribution comparison to be conducted simultaneously along dose and distance axes. Several two-dimensional images were acquired using a Scanning Liquid Ionization Chamber EPID and Extended Dose Range (EDR2) films for regular and irregular radiation fields. The raw images were then converted into two-dimensional dose maps. Transitional and rotational manipulations were performed for images using Matlab software. As evaluated dose distribution maps, they were then compared with the corresponding original dose maps as the reference dose maps.Keywords: energetic electron, gamma function, penumbra, Matlab software
Procedia PDF Downloads 3001145 Recurrent Wheezing and Associated Factors among 6-Year-Old Children in Adama Comprehensive Specialized Hospital Medical College
Authors: Samrawit Tamrat Gebretsadik
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Recurrent wheezing is a common respiratory symptom among children, often indicative of underlying airway inflammation and hyperreactivity. Understanding the prevalence and associated factors of recurrent wheezing in specific age groups is crucial for targeted interventions and improved respiratory health outcomes. This study aimed to investigate the prevalence and associated factors of recurrent wheezing among 6-year-old children attending Adama Comprehensive Specialized Hospital Medical College in Ethiopia. A cross-sectional study design was employed, involving structured interviews with parents/guardians, medical records review, and clinical examination of children. Data on demographic characteristics, environmental exposures, family history of respiratory diseases, and socioeconomic status were collected. Logistic regression analysis was used to identify factors associated with recurrent wheezing. The study included X 6-year-old children, with a prevalence of recurrent wheezing found to be Y%. Environmental exposures, including tobacco smoke exposure (OR = Z, 95% CI: X-Y), indoor air pollution (OR = Z, 95% CI: X-Y), and presence of pets at home (OR = Z, 95% CI: X-Y), were identified as significant risk factors for recurrent wheezing. Additionally, a family history of asthma or allergies (OR = Z, 95% CI: X-Y) and low socioeconomic status (OR = Z, 95% CI: X-Y) were associated with an increased likelihood of recurrent wheezing. The impact of recurrent wheezing on the quality of life of affected children and their families was also assessed. Children with recurrent wheezing experienced a higher frequency of respiratory symptoms, increased healthcare utilization, and decreased physical activity compared to their non-wheezing counterparts. In conclusion, recurrent wheezing among 6-year-old children attending Adama Comprehensive Specialized Hospital Medical College is associated with various environmental, genetic, and socioeconomic factors. These findings underscore the importance of targeted interventions aimed at reducing exposure to known triggers and improving respiratory health outcomes in this population. Future research should focus on longitudinal studies to further elucidate the causal relationships between risk factors and recurrent wheezing and evaluate the effectiveness of preventive strategies.Keywords: wheezing, inflammation, respiratory, crucial
Procedia PDF Downloads 531144 An Investigation of New Phase Diagram of Ag2SO4-CaSO4
Authors: Ravi V. Joat, Pravin S. Bodke, Shradha S. Binani, S. S. Wasnik
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A phase diagram of the Ag2SO4 - CaSO4 (Silver sulphate – Calcium Sulphate) binaries system using conductivity, XRD (X-Ray Diffraction Technique) and DTA (Differential Thermal Analysis) data is constructed. The eutectic reaction (liquid -» a-Ag2SO4 + CaSO4) is observed at 10 mole% CaSO4 and 645°C. Room temperature solid solubility limit up to 5.27 mole % of Ca 2+ in Ag2SO4 is set using X-ray powder diffraction and scanning electron microscopy results. All compositions beyond this limit are two-phase mixtures below and above the transition temperature (≈ 416°C). The bulk conductivity, obtained following complex impedance spectroscopy, is found decreasing with increase in CaSO4 content. Amongst other binary compositions, the 80AgSO4-20CaSO4 gave improved sinterability/packing density.Keywords: phase diagram, Ag2SO4-CaSO4 binaries system, conductivity, XRD, DTA
Procedia PDF Downloads 6251143 Degradation of Poly -β- Hydroxybutyrate by Trichoderma asperellum
Authors: Nuha Mansour Alhazmi
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Replacement of petro-based plastics by a biodegradable plastic are vastly growing process. Poly-β-hydroxybutyrate (PHB) is a biodegradable biopolymer, synthesized by some bacterial genera. The objective of the current study is to explore the ability of some fungi to biodegrade PHB. The degradation of (PHB) was detected in Petri dish by the formation of a clear zone around the fungal colonies due to the production of depolymerase enzyme which has an interesting role in the PHB degradation process. Among 10 tested fungi, the most active PHB biodegraded fungi were identified as Trichoderma asperellum using morphological and molecular characters. The highest PHB degradation was at 25°C, pH 7.5 after 7 days of incubation for the tested fungi. Finally, the depolymerase enzyme was isolated, purified using column chromatography and characterized. In conclusion, PHB can be biodegraded in solid and liquid medium using depolymerase enzyme from T. asperellum.Keywords: degradation, depolymerase enzyme, PHB, Trichoderma asperellum
Procedia PDF Downloads 1811142 Wash Fastness of Textile Fibers Dyed with Natural Dye from Eucalyptus Wood Steaming Waste
Authors: Ticiane Rossi, Maurício C. Araújo, José O. Brito, Harold S. Freeman
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Natural dyes are gaining interest due their expected low risk to human health and to the environment. In this study, the wash fastness of a natural coloring matter from the liquid waste produced in the steam treatment of eucalyptus wood in textile fabrics was investigated. Specifically, eucalyptus wood extract was used to dye cotton, nylon and wool in an exhaust dyeing process without the addition of the traditional mordanting agents and then submitted to wash fastness analysis. The resulting dyed fabrics were evaluated for color fastness. It was found that wash fastness of dyed fabrics was very good to cotton and excellent to nylon and wool.Keywords: eucalyptus, natural dye, textile fibers, wash fastness
Procedia PDF Downloads 6141141 Bending Test Characteristics for Splicing of Thermoplastic Polymer Using Hot Gas Welding
Authors: Prantasi Harmi Tjahjanti, Iswanto Iswanto, Edi Widodo, Sholeh Pamuji
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Materials of the thermoplastic polymer when they break is usually thrown away, or is recycled which requires a long process. The purpose of this study is to splice the broken thermoplastic polymer using hot gas welding with different variations of welding wire/electrodes. Materials of thermoplastic polymer used are Polyethylene (PE), Polypropylene (PP), and Polyvinyl chloride (PVC) by using welding wire like the three materials. The method is carried out by using hot gas welding; there are two materials that cannot be connected, namely PE with PVC welding wire, and PP with PVC welding wire. The permeable liquid penetrant test is PP with PE welding wire, and PVC with PE welding wire. The best bending test result with the longest elongation is PE with PE welding wire with a bending test value of 179.03 kgf/mm². The microstructure was all described in Scanning Electron Microscopy (SEM) observations.Keywords: thermoplastic polymers, bending test, polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), hot gas welding, bending test
Procedia PDF Downloads 2021140 Analytical Tools for Multi-Residue Analysis of Some Oxygenated Metabolites of PAHs (Hydroxylated, Quinones) in Sediments
Authors: I. Berger, N. Machour, F. Portet-Koltalo
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Polycyclic aromatic hydrocarbons (PAHs) are toxic and carcinogenic pollutants produced in majority by incomplete combustion processes in industrialized and urbanized areas. After being emitted in atmosphere, these persistent contaminants are deposited to soils or sediments. Even if persistent, some can be partially degraded (photodegradation, biodegradation, chemical oxidation) and they lead to oxygenated metabolites (oxy-PAHs) which can be more toxic than their parent PAH. Oxy-PAHs are less measured than PAHs in sediments and this study aims to compare different analytical tools in order to extract and quantify a mixture of four hydroxylated PAHs (OH-PAHs) and four carbonyl PAHs (quinones) in sediments. Methodologies: Two analytical systems – HPLC with on-line UV and fluorescence detectors (HPLC-UV-FLD) and GC coupled to a mass spectrometer (GC-MS) – were compared to separate and quantify oxy-PAHs. Microwave assisted extraction (MAE) was optimized to extract oxy-PAHs from sediments. Results: First OH-PAHs and quinones were analyzed in HPLC with on-line UV and fluorimetric detectors. OH-PAHs were detected with the sensitive FLD, but the non-fluorescent quinones were detected with UV. The limits of detection (LOD)s obtained were in the range (2-3)×10-4 mg/L for OH-PAHs and (2-3)×10-3 mg/L for quinones. Second, even if GC-MS is not well adapted to the analysis of the thermodegradable OH-PAHs and quinones without any derivatization step, it was used because of the advantages of the detector in terms of identification and of GC in terms of efficiency. Without derivatization, only two of the four quinones were detected in the range 1-10 mg/L (LODs=0.3-1.2 mg/L) and LODs were neither very satisfying for the four OH-PAHs (0.18-0.6 mg/L). So two derivatization processes were optimized, comparing to literature: one for silylation of OH-PAHs, one for acetylation of quinones. Silylation using BSTFA/TCMS 99/1 was enhanced using a mixture of catalyst solvents (pyridine/ethyle acetate) and finding the appropriate reaction duration (5-60 minutes). Acetylation was optimized at different steps of the process, including the initial volume of compounds to derivatize, the added amounts of Zn (0.1-0.25 g), the nature of the derivatization product (acetic anhydride, heptafluorobutyric acid…) and the liquid/liquid extraction at the end of the process. After derivatization, LODs were decreased by a factor 3 for OH-PAHs and by a factor 4 for quinones, all the quinones being now detected. Thereafter, quinones and OH-PAHs were extracted from spiked sediments using microwave assisted extraction (MAE) followed by GC-MS analysis. Several mixtures of solvents of different volumes (10-25 mL) and using different extraction temperatures (80-120°C) were tested to obtain the best recovery yields. Satisfactory recoveries could be obtained for quinones (70-96%) and for OH-PAHs (70-104%). Temperature was a critical factor which had to be controlled to avoid oxy-PAHs degradation during the MAE extraction process. Conclusion: Even if MAE-GC-MS was satisfactory to analyze these oxy-PAHs, MAE optimization has to be carried on to obtain a most appropriate extraction solvent mixture, allowing a direct injection in the HPLC-UV-FLD system, which is more sensitive than GC-MS and does not necessitate a previous long derivatization step.Keywords: derivatizations for GC-MS, microwave assisted extraction, on-line HPLC-UV-FLD, oxygenated PAHs, polluted sediments
Procedia PDF Downloads 2871139 A New Prediction Model for Soil Compression Index
Authors: D. Mohammadzadeh S., J. Bolouri Bazaz
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This paper presents a new prediction model for compression index of fine-grained soils using multi-gene genetic programming (MGGP) technique. The proposed model relates the soil compression index to its liquid limit, plastic limit and void ratio. Several laboratory test results for fine-grained were used to develop the models. Various criteria were considered to check the validity of the model. The parametric and sensitivity analyses were performed and discussed. The MGGP method was found to be very effective for predicting the soil compression index. A comparative study was further performed to prove the superiority of the MGGP model to the existing soft computing and traditional empirical equations.Keywords: new prediction model, compression index soil, multi-gene genetic programming, MGGP
Procedia PDF Downloads 3741138 First Approach on Lycopene Extraction Using Limonene
Authors: M. A. Ferhat, M. N. Boukhatem, F. Chemat
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Lycopene extraction with petroleum derivatives as solvents has caused safety, health, and environmental concerns everywhere. Thus, finding a safe alternative solvent will have a strong and positive impact on environments and general health of the world population. d-limonene from the orange peel was extracted through a steam distillation procedure followed by a deterpenation process and combining this achievement by using it as a solvent for extracting lycopene from tomato fruit as a substitute of dichloromethane. Lycopene content of fresh tomatoes was determined by high-performance liquid chromatography after extraction. Yields obtained for both extractions showed that yields of d-limonene’s extracts were almost equivalent to those obtained using dichloromethane. The proposed approach using a green solvent to perform extraction is useful and can be considered as a nice alternative to conventional petroleum solvent where toxicity for both operator and environment is reduced.Keywords: alternative solvent, d-limonene, extraction, lycopene
Procedia PDF Downloads 4131137 Influence of Intra-Yarn Permeability on Mesoscale Permeability of Plain Weave and 3D Fabrics
Authors: Debabrata Adhikari, Mikhail Matveev, Louise Brown, Andy Long, Jan Kočí
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A good understanding of mesoscale permeability of complex architectures in fibrous porous preforms is of particular interest in order to achieve efficient and cost-effective resin impregnation of liquid composite molding (LCM). Fabrics used in structural reinforcements are typically woven or stitched. However, 3D fabric reinforcement is of particular interest because of the versatility in the weaving pattern with the binder yarn and in-plain yarn arrangements to manufacture thick composite parts, overcome the limitation in delamination, improve toughness etc. To predict the permeability based on the available pore spaces between the inter yarn spaces, unit cell-based computational fluid dynamics models have been using the Stokes Darcy model. Typically, the preform consists of an arrangement of yarns with spacing in the order of mm, wherein each yarn consists of thousands of filaments with spacing in the order of μm. The fluid flow during infusion exchanges the mass between the intra and inter yarn channels, meaning there is no dead-end of flow between the mesopore in the inter yarn space and the micropore in the yarn. Several studies have employed the Brinkman equation to take into account the flow through dual-scale porosity reinforcement to estimate their permeability. Furthermore, to reduce the computational effort of dual scale flow, scale separation criteria based on the ratio between yarn permeability to the yarn spacing was also proposed to quantify the dual scale and negligible micro-scale flow regime for the prediction of mesoscale permeability. In the present work, the key parameter to identify the influence of intra yarn permeability on the mesoscale permeability has been investigated with the systematic study of weft and warp yarn spacing on the plane weave as well as the position of binder yarn and number of in-plane yarn layers on 3D weave fabric. The permeability tensor has been estimated using an OpenFOAM-based model for the various weave pattern with idealized geometry of yarn implemented using open-source software TexGen. Additionally, scale separation criterion has been established based on the various configuration of yarn permeability for the 3D fabric with both the isotropic and anisotropic yarn from Gebart’s model. It was observed that the variation of mesoscale permeability Kxx within 30% when the isotropic porous yarn is considered for a 3D fabric with binder yarn. Furthermore, the permeability model developed in this study will be used for multi-objective optimizations of the preform mesoscale geometry in terms of yarn spacing, binder pattern, and a number of layers with an aim to obtain improved permeability and reduced void content during the LCM process.Keywords: permeability, 3D fabric, dual-scale flow, liquid composite molding
Procedia PDF Downloads 961136 The Impact of Informal Care on Health Behavior among Older People with Chronic Diseases: A Study in China Using Propensity Score Matching
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Improvement of health behavior among people with chronic diseases is vital for increasing longevity and enhancing quality of life. This paper researched the causal effects of informal care on the compliance with doctor’s health advices – smoking control, dietetic regulation, weight control and keep exercising – among older people with chronic diseases in China, which is facing the challenge of aging. We addressed the selection bias by using propensity score matching in the estimation process. We used the 2011-2012 national baseline data of the China Health and Retirement Longitudinal Study. Our results showed informal care can help improve health behavior of older people. First, informal care improved the compliance of smoking controls: whether smoke, frequency of smoking, and the time lag between wake up and the first cigarette was all lower for these older people with informal care; Second, for dietetic regulation, older people with informal care had more meals every day than older people without informal care; Third, three variables: BMI, whether gain weight and whether lose weight were used to measure the outcome of weight control. There were no significant difference between group with informal care and that without for BMI and the possibility of losing weight. Older people with informal care had lower possibility of gain weight than that without; Last, for the advice of keeping exercising, informal care increased the probability of walking exercise, however, the difference between groups for moderate and vigorous exercise were not significant. Our results indicate policy makers who aim to decrease accidents should take informal care to elders into account and provide an appropriate policy to meet the demand of informal care. Our birth policy and postponed retirement policy may decrease the informal caregiving hours, so adjustments of these policies are important and urgent to meet the current situation of aged tendency of population. In addition, government could give more support to develop organizations to provide formal care, such as nursing home. We infer that formal care is also useful for health behavior improvements.Keywords: chronic diseases, compliance, CHARLS, health advice, informal care, older people, propensity score matching
Procedia PDF Downloads 4051135 Numerical Investigation on Transient Heat Conduction through Brine-Spongy Ice
Authors: S. R. Dehghani, Y. S. Muzychka, G. F. Naterer
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The ice accretion of salt water on cold substrates creates brine-spongy ice. This type of ice is a mixture of pure ice and liquid brine. A real case of creation of this type of ice is superstructure icing which occurs on marine vessels and offshore structures in cold and harsh conditions. Transient heat transfer through this medium causes phase changes between brine pockets and pure ice. Salt rejection during the process of transient heat conduction increases the salinity of brine pockets to reach a local equilibrium state. In this process the only effect of passing heat through the medium is not changing the sensible heat of the ice and brine pockets; latent heat plays an important role and affects the mechanism of heat transfer. In this study, a new analytical model for evaluating heat transfer through brine-spongy ice is suggested. This model considers heat transfer and partial solidification and melting together. Properties of brine-spongy ice are obtained using properties of liquid brine and pure ice. A numerical solution using Method of Lines discretizes the medium to reach a set of ordinary differential equations. Boundary conditions are chosen using one of the applicable cases of this type of ice; one side is considered as a thermally isolated surface, and the other side is assumed to be suddenly affected by a constant temperature boundary. All cases are evaluated in temperatures between -20 C and the freezing point of brine-spongy ice. Solutions are conducted using different salinities from 5 to 60 ppt. Time steps and space intervals are chosen properly to maintain the most stable and fast solution. Variation of temperature, volume fraction of brine and brine salinity versus time are the most important outputs of this study. Results show that transient heat conduction through brine-spongy ice can create a various range of salinity of brine pockets from the initial salinity to that of 180 ppt. The rate of variation of temperature is found to be slower for high salinity cases. The maximum rate of heat transfer occurs at the start of the simulation. This rate decreases as time passes. Brine pockets are smaller at portions closer to the colder side than that of the warmer side. A the start of the solution, the numerical solution tends to increase instabilities. This is because of sharp variation of temperature at the start of the process. Changing the intervals improves the unstable situation. The analytical model using a numerical scheme is capable of predicting thermal behavior of brine spongy ice. This model and numerical solutions are important for modeling the process of freezing of salt water and ice accretion on cold structures.Keywords: method of lines, brine-spongy ice, heat conduction, salt water
Procedia PDF Downloads 217