Search results for: thermal influence of boundary parameters

Authors: Kalsoom Shaikh, Saima Memon, Riffat Sultana

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Water pollution affects amphibians because they are intimately water dependent. The permeable skin makes amphibians very sensitive to the physico-chemical parameters of their aquatic environment. They spawn in water bodies where quality of water can affect the growth, development, and survival of their eggs which may die even before hatching into larvae or developing into adults due to water contamination. Considering the importance of amphibians in agriculture, food web, ecosystem and pharmaceutics as well as adverse impact of environmental degradation on them, present study was proposed to comprehensively determine the status of their diversity and habitats in Sindh province of Pakistan so as to execute monitoring for their conservation in future. Physico-chemical parameters including pH, EC (electric conductivity), TDS (total dissolved solids), T-Hard (total hardness), T-Alk (total alkalinity), Cl (chloride), CO₂ (carbon dioxide), SO₄ (sulphate), PO₄ (phosphate), NO₂ (nitrite) and NO₃ (nitrate) were analyzed from amphibian habitats using instruments and methodology of analytical grade. The results of present study after being compared with scientific data provided by different researchers and EPA (environmental protection agency), it was concluded that amphibian habitats consisted of high values of analyzed parameters except pH and CO₂. Entire study area required an urgent implementation of conservation actions for saving amphibians.

Keywords: amphibians, diversity, habitats, physico-chemical parameters, water quality, Pakistan, Sindh Province

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Authors: Asma Perveen, M. P. Jahan

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Ni alloys have managed to cover wide range of applications such as automotive industries, oil gas industries, and aerospace industries. However, these alloys impose challenges while using conventional machining technologies. On the other hand, Micro-Electro-Discharge machining (micro-EDM) is a non-conventional machining method that uses controlled sparks energy to remove material irrespective of the materials hardness. There has been always a huge interest from the industries for developing optimum methodology and parameters in order to enhance the productivity of micro-EDM in terms of reducing machining time and tool wear for different alloys. Therefore, the aims of this study are to investigate the effects of the micro-EDM process parameters, in order to find their optimal values. The input process parameters include voltage, capacitance, and electrode rotational speed, whereas the output parameters considered are machining time, entrance diameter of hole, overcut, tool wear, and crater size. The surface morphology and element characterization are also investigated with the use of SEM and EDX analysis. The experimental result indicates the reduction of machining time with the increment of discharge energy. Discharge energy also contributes to the enlargement of entrance diameter as well as overcut. In addition, tool wears show reduction with the increase of discharge energy. Moreover, crater size is found to be increased in size along with the increment of discharge energy.

Keywords: micro holes, micro EDM, Ni Alloy, discharge energy

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Authors: Vivek Vaishnav, Shamim Akhtar Ansari

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Teak (Tectona grandis L.f.) belonging to plant family Lamiaceae and the most commercialized timber species is endemic to South-Asia. The adaptive fitness of the species metapopulation was evaluated through its genetic differentiation and assessing the influence of geo-climatic conditions. 290 genotypes were sampled from 29 locations of its natural distribution and the genetic data was incorporated with geo-climatic parameters. Through Bayesian approach based analysis of 43 highly polymorphic ISSR markers, six homogeneous clusters (0.8% genetic variability) were identified. The six clusters were found with the various regimes of the temperature range, i.e., I - 9.10±1.35⁰C, II -6.35±0.21⁰C, III -12.21±0.43⁰C, IV - 10.8±1.06⁰C, V - 11.67±3.04⁰C, and VI - 12.35±0.21⁰C. The population had a very high percentage of LD (21.48%) among the amplified loci possibly due to experiencing restricted gene flow as well as co-adaptation and association of distant/diverse loci/alleles as a result of the stabilized climatic conditions and countless cycles of historical recombination events on a large geological timescale. The same possibly accounts for the narrow distribution of teak as a climax species in the tropical deciduous forests of the country. The regions of strong LD in teak genome significantly associated with climatic parameters also reflect that the species is tolerant to the wide regimes of the temperature range and may possibly withstand global warming and climate change in the coming millennium.

Keywords: Bayesian analysis, inter simple sequence repeat, linkage disequilibrium, marker-geoclimatic association

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Authors: Han-Woong Ahn, In-Gun Kim, Hyun-Seok Hong, Dong-Woo Kang, Ju Lee

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It is important to accurately identify machine parameters for direct vector control. To obtain the parameter values, traditional methods can be used such as no-load and rotor locked tests. However, there are many differences between values obtained from the traditional tests and actual values. In addition, there are drawbacks that additional equipment and cost are required for the experiment. Therefore, it is hard to temporary operation to estimate induction motor parameters. Therefore, this paper deals with the estimation algorithm of induction motor parameters without a motor operation and the measurement from additional equipment such as sensors and dynamometer. The validity and usefulness of the estimation algorithm considering inverter nonlinearity is verified by comparing the conventional method with the proposed method.

Keywords: induction motor, parameter, off-line estimation, inverter nonlinearity

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Authors: M. Veeresham

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The microstructure, texture, phase stability, and tensile properties of annealed Ta_0.5Nb_0.5Hf_0.5ZrTi_1.5 alloy have been investigated in the present research. The alloy was severely hybrid-rolled up to 93.5% thickness reduction, subsequently rolled samples subjected to an annealing treatment at 800 °C and 1000 °C temperatures for 1 h. Consequently, the rolled condition and both annealed temperatures have a body-centered cubic (BCC) structure. Furthermore, quantitative texture measurements (orientation distribution function (ODF) analysis) and microstructural examinations (analytical electron backscatter diffraction (EBSD) maps) permitted to establish a good relationship between annealing texture and microstructure and universal testing machine (UTM) utilized for obtaining the mechanical properties. Impressive room temperature tensile properties combination with the tensile strength (1380 MPa) and (24.7%) elongation is achieved for the 800 °C heat-treated condition. The evolution of the coarse microstructure featured in the case of 1000 °C annealed temperature ascribed to the influence of high thermal energy.

Keywords: refractory high entropy alloys, hybrid-rolling, recrystallization, microstructure, tensile properties

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Authors: P. Sathyathas, H. M. I. S. W. Herath, T. Amalraj, U. J. M. A. L. Jayasinghe

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Over two thirds of medical radiation can now be attributed to Computed Tomography (CT). There is little information on amount of radiation received from multiphase CT scan of abdomen- pelvic region in clinical practice. We sought to estimate the radiation dose and associated exposure parameters in the multiphase abdomen - pelvic scan of Multideteror Computed Tomography (MDCT) studies in clinical practice. This was a retrospective cross sectional studies describing radiation dose associated with main exposure parameters in diagnostic multiphase abdomen - pelvic scans performed on 152 consecutive patients by two different sixteen slice CT scanners. Patient information, exposure parameters of CTDI (volume), DLP, kVp, mAs and pitch were recorded for every phases of abdomen- a pelvic study from dose report of MDCT scanners (MDCTs). Age of patients range from 14 years to 87 years in both MDCT scanners. Overall CTDI (volume) median was 63.8 (±10.4) mGy for a multiphase abdominal-pelvic scan with scanner A while it was 35.4 (±15.6) mGy for scanner B. Patients' effective dose for multiphase abdomen - pelvic CT scan range from 8.2 mSv to 58 mSv. Median effective dose for patients, who underwent multiphase abdomen- pelvis scan with scanner A and B were 38.5 (± 8.2) mSv and 21.3 (± 8.6) mSv respectively. Median value of exposure parameters of mAs, kVp and pitch, were 150 (±29.7), 130 (±15.3) and 1.3 (±0.1) respectively in scanner A. In scanner B; they were 60 (±14.5), 120 and 1. The median effective dose for patients between multiphase abdomen-pelvic scan of both MDCT, a significant different (P<0.05) was observed. Multiphase abdomen – pelvic scan of clinical study shows significant different of effective dose with reference level of phantom studies (8-14mSv) and it depends on the type of vendors.

Keywords: abdomen-pelvic region, computed tomography, exposure parameters, radiation dose

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Authors: Hua Li, Hongwu Deng

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The turbine blade's leading edge is usually cooled by jet impingement cooling technology due to the heaviest heat load. For a rotating turbine blade, however, the channel orientation (β, the angle between the jet direction and the rotating plane) could play an important role in influencing the flow field and heat transfer. Therefore, in this work, the effects of channel orientation (from 90° to 180°) on heat transfer in a jet impingement cooling channel are experimentally investigated. Furthermore, the investigations are conducted under an isothermal boundary condition. Both the jet-to-target surface distance and jet-to-jet spacing are three times the jet hole diameter. The jet Reynolds number is 5,000, and the maximum jet rotation number reaches 0.24. The results show that the rotation-induced variations of heat transfer are different in each channel orientation. In the cases of 90°≤β≤135°, a vortex generated in the low-radius region of the supply channel changes the mass-flowrate distribution in each jet hole. Therefore, the heat transfer in the low-radius region decreases with the rotation number, whereas the heat transfer in the high-radius region increases, indicating that a larger temperature gradient in the radial direction could appear in the turbine blade's leading edge. When 135°<β≤180°; however, the heat transfer of the entire stagnant zone decreases with the rotation number. The rotation-induced jet deflection is the primary factor that weakens the heat transfer, and jets cannot reach the target surface at high rotation numbers. For the downstream regions, however, the heat transfer is enhanced by 50%-80% in every channel orientation because the dead zone is broken by the rotation-induced secondary flow in the impingement channel.

Keywords: heat transfer, jet impingement cooling, channel orientation, high rotation number, isothermal boundary

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Authors: Manoj Kumar, Rajesh Kumar

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With the favourable geographical conditions at Indian-subcontinent, it is suitable for flourishing renewable energy. Increasing amount of dependence on coal and other conventional sources is driving the world into pollution and depletion of resources. This paper presents the statistics of energy consumption and energy generation in Indian Sub-continent, which notifies us with the increasing energy demands surpassing energy generation. With the aggrandizement in demand for energy, usage of coal has increased, since the major portion of energy production in India is from thermal power plants. The increase in usage of thermal power plants causes pollution and depletion of reserves; hence, a paradigm shift to renewable sources is inevitable. In this work, the capacity and potential of renewable sources in India are analyzed. Based on the analysis of this work, future potential of these sources is estimated.

Keywords: depletion of reserves, energy consumption and generation, emmissions, global warming, renewable sources

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Authors: Lingaraju Dumpala, Narasa Raju Gosangi

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Friction Stir Welding (FSW) is relatively new, environmentally friendly, versatile, and widely used joining technique for soft materials such as aluminum. FSW has got a lot of attention as a solid-state joining method which avoids many common problems of fusion welding and provides an improved way of producing aluminum joints in a faster way. FSW can be used for various aerospace, defense, automotive and transportation applications. It is necessary to understand the friction stir welded joints and its characteristics to use this new joining technique in critical applications. This study investigated the mechanical properties of friction stir welded aluminum 6063 alloys. FSW is carried out based on the design of experiments using L16 mixed level array by considering tool rotational speeds, tool feed rate and tool tilt angles as process parameters. The optimization of process parameters is carried by Taguchi based regression analysis and the significance of process parameters is analyzed using ANOVA. It is observed that the considered process parameters are high influences the mechanical properties of Al6063.

Keywords: FSW, aluminum alloy, mechanical properties, optimization, Taguchi, ANOVA

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Authors: Mubarek Alpkiray, Tan Nguyen, Arild Saasen

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Geothermal drilling operations contain numerous challenges that are encountered to increase the well cost and nonproductive time. Fluid loss is one of the most undesirable troublesome that can cause well abandonment in geothermal drilling. Lost circulation can be seen due to natural fractures, high mud weight, and extremely high formation temperatures. This challenge may cause wellbore stability problems and lead to expensive drilling operations. Wellbore stability is the main domain that should be considered to mitigate or prevent fluid loss into the formation. This paper describes the causes of fluid loss in the Pamukoren geothermal field in Turkey. A geomechanics approach integration and assessment is applied to help the understanding of fluid loss problems. In geothermal drillings, geomechanics is primarily based on rock properties, in-situ stress characterization, the temperature of the rock, determination of stresses around the wellbore, and rock failure criteria. Since a high-temperature difference between the wellbore wall and drilling fluid is presented, temperature distribution through the wellbore is estimated and implemented to the wellbore stability approach. This study reviewed geothermal drilling data to analyze temperature estimation along the wellbore, the cause of fluid loss and stored electric capacity of the reservoir. Our observation demonstrates the geomechanical approach's significant role in understanding safe drilling operations on high-temperature wells. Fluid loss is encountered due to thermal stress effects around the borehole. This paper provides a wellbore stability analysis for a geothermal drilling operation to discuss the causes of lost circulation resulting in nonproductive time and cost.

Keywords: geothermal wells, drilling, wellbore stresses, drilling fluid loss, thermal stress

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Authors: Kazuyoshi Mori

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In this paper, we consider the parametrization of the discrete-time systems without the unit-delay element within the framework of the factorization approach. In the parametrization, we investigate the number of required parameters. We consider single-input single-output systems in this paper. By the investigation, we find, on the discrete-time systems without the unit-delay element, three cases that are (1) there exist plants which require only one parameter and (2) two parameters, and (3) the number of parameters is at most three.

Keywords: factorization approach, discrete-time system, parameterization of stabilizing controllers, system without unit-delay

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Authors: Manoj Malviya, Shubham Shinde

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The present study focuses on the determination of torsional stiffness of a space frame chassis and comparison of elements used in the Finite Element Analysis of frame. The study also discusses various concepts and design aspects of a space frame chassis with the emphasis on their applicability in BAJA SAE vehicles. Torsional stiffness is a very important factor that determines the chassis strength, vehicle control, and handling. Therefore, it is very important to determine the torsional stiffness of the vehicle before designing an optimum chassis so that it should not fail during extreme conditions. This study determines the torsional stiffness of frame with respect to suspension shocks, roll-stiffness and anti-roll bar rates. A spring model is developed to study the effects of suspension parameters. The engine greatly contributes to torsional stiffness, and therefore, its effects on torsional stiffness need to be considered. Deflections in the tire have not been considered in the present study. The proper element shape should be selected to analyze the effects of various loadings on chassis while implementing finite element methods. The study compares the accuracy of results and computational time for different element types. Shape functions of these elements are also discussed. Modelling methodology is discussed for the multibody analysis of chassis integrated with suspension arms and engine. Proper boundary conditions are presented so as to replicate the real life conditions.

Keywords: space frame chassis, torsional stiffness, multi-body analysis of chassis, element selection

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Authors: A. A. A. Aboalnour, Ahmed M. Amasaib, Mohammed-Almujtaba A. Mohammed-Farah, Abdelhakam, A. Noreldien

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This paper presents a design and study of Parabolic Trough Solar Collector (PTC). Mathematical models were used in this work to find the direct and reflected solar radiation from the air layer on the surface of the earth per hour based on the total daily solar radiation on a horizontal surface. Also mathematical models had been used to calculate the radiation of the tilted surfaces. Most of the ingredients used in this project as previews data required on several solar energy applications, thermal simulation, and solar power systems. In addition, mathematical models had been used to study the flow of the fluid inside the tube (receiver), and study the effect of direct and reflected solar radiation on the pressure, temperature, speed, kinetic energy and forces of fluid inside the tube. Finally, the mathematical models had been used to study the (PTC) performances and estimate its thermal efficiency.

Keywords: CFD, experimental, mathematical models, parabolic trough, radiation

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Authors: A. Mohammadi, S. Asghari, M. Aien, M. Rashidinejad

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After emergent of alternative current networks and their popularity, asynchronous motors became more widespread than other kinds of industrial motors. In order to control and run these motors efficiently, an accurate estimation of motor parameters is needed. There are different methods to obtain these parameters such as rotor locked test, no load test, DC test, analytical methods, and so on. The most common drawback of these methods is their inaccuracy in estimation of some motor parameters. In order to remove this concern, a novel method for parameter estimation of induction motors using particle swarm optimization (PSO) algorithm is proposed. In the proposed method, transient state of motor is used for parameter estimation. Comparison of the simulation results purtuined to the PSO algorithm with other available methods justifies the effectiveness of the proposed method.

Keywords: induction motor, motor parameter estimation, PSO algorithm, analytical method

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Authors: Y. Laib Dit Leksir, S. Bouhouche

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Analysis and processing of data bases resulting from infrared thermal measurements made on the electrical installation requires the development of new tools in order to obtain correct and additional information to the visual inspections. Consequently, the methods based on the capture of infrared digital images show a great potential and are employed increasingly in various fields. Although, there is an enormous need for the development of effective techniques to analyse these data base in order to extract relevant information relating to the state of the equipments. Our goal consists in introducing recent techniques of modeling based on new methods, image and signal processing to develop mathematical models in this field. The aim of this work is to capture the anomalies existing in electrical equipments during an inspection of some machines using A40 Flir camera. After, we use binarisation techniques in order to select the region of interest and we make comparison between these methods of thermal images obtained to choose the best one.

Keywords: infrared thermography, defect detection, troubleshooting, electrical equipment

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Authors: S. Nishat Fatima Rizvi, Tulika Chandra, Abbas Ali Mahdi, Devisha Agarwal

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Introduction: Blood components are an unexplored area prone to numerous discoveries which influence patient’s care. Experiments at different levels will further change the present concept of blood banking. Hyperlipidemia is a condition of elevated plasma level of low-density lipoprotein (LDL) as well as decreased plasma level of high-density lipoprotein (HDL). Studies show that platelets play a vital role in the progression of atherosclerosis and thrombosis, a major cause of death worldwide. They are activated by many triggers like elevated LDL in the blood resulting in aggregation and formation of plaques. Hyperlipidemic platelets are frequently transfused to patients with various disorders. Screening the random donor platelets for hyperlipidemia and correlating the condition with other donor criteria such as lipid rich diet, oral contraceptive pills intake, weight, alcohol intake, smoking, sedentary lifestyle, family history of heart diseases will lead to further deciding the exclusion criteria for donor selection. This will help in making the patients safe as well as the donor deferral criteria more stringent to improve the quality of blood supply. Technical evaluation and assessment will enable blood bankers to supply safe blood and improve the guidelines for blood safety. Thus, we try to study the correlation between hyperlipidemic platelets with platelets parameters, weight, and specific history of the donors. Methodology: This case control study included 100 blood samples of Blood donors, out of 100 only 30 samples were found to be hyperlipidemic and were included as cases, while rest were taken as controls. Lipid Profile were measured by fully automated analyzer (TRIGL:triglycerides),(LDL-C:LDL –Cholesterol plus 2nd generation),CHOL 2: Cholesterol Gen 2), HDL C 3: HDL-Cholesterol plus 3rdgeneration)-(Cobas C311-Roche Diagnostic).And Platelets parameters were analyzed by the Sysmex KX21 automated hematology analyzer. Results: A significant correlation was found amongst hyperlipidemic level in single time donor. In which 80% donors have history of heart disease, 66.66% donors have sedentary life style, 83.3% donors were smokers, 50% donors were alcoholic, and 63.33% donors had taken lipid rich diet. Active physical activity was found amongst 40% donors. We divided donors sample in two groups based on their body weight. In group 1, hyperlipidemic samples: Platelet Parameters were 75% in normal 25% abnormal in >70Kg weight while in 50-70Kg weight 90% were normal 10% were abnormal. In-group 2, Non Hyperlipidemic samples: platelet Parameters were 95% normal and 5% abnormal in >70Kg weight, while in 50-70Kg Weight, 66.66% normal and 33.33% abnormal. Conclusion: The findings indicate that Hyperlipidemic status of donors may affect the platelet parameters and can be distinguished on history by their weight, Smoking, Alcoholic intake, Sedentary lifestyle, Active physical activity, Lipid rich diet, Oral contraceptive pills intake, and Family history of heart disease. However further studies on a large sample size will affirm this finding.

Keywords: blood donors, hyperlipidemia, platelet, weight

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Authors: Hanan, S. Siam, Safaa A. Mahmoud, A. S. Taalab

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A pot experiment was conducted in greenhouse of NRC, Dokki, Cairo, Egypt to study the response of wheat plants to different levels of superphosphate at (60kg P2O5 or 30 kg P2O5) with or without potassium silicate or chicken compost (2.5 ton/fed.) on growth yield and nutrients status especially, and phosphorus and silica availability. Data reveal that the addition either chicken or compost increased significantly affected on all the growth and yield parameters as well as nutrients status and protein of the different parts of wheat plants if compared with control (60kg P2O5 or 30 kg P2O5). Data also reveal that the highest mean values were obtained when potassium silicate with was added to 60 kg P2O5, while the lowest values of the previous parameters were obtained when 30 kg P2O5 alone was added to plants. Furthermore, data indicated that the highest mean values of all mentioned parameters were obtained when chicken compost was applied with any rate of P as compared with silica addition at the same rates of P. According to the results, the highest values of all mentioned parameters were obtained when addition of chicken compost and potassium silicate including the high rate of P at (60 kg P2O5) while the lowest values of the previous parameters were obtained when plants received of phosphorus (30 kg P2O5) alone.

Keywords: wheat, yield, chicken compost, potassium, phosphorus, silicate, nutrients status

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Authors: Syed Faizan Hassan Shah

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Introduction: Burn injuries are among the most devastating of all injuries. Burns is the fourth most common type of trauma worldwide. Ap?proximately 90 percent of burns occur in low to middle-income countries. Nearly half a million Americans each year, with approximately 40,000 hospitalizations and 3,400 deaths annually, suffer burns. The survival rate for admitted burn patients has improved consistently over the past four decades, largely attributed to national decreases in burn size, improvements in burn critical care, and advancements in burn wound care. Objectives: The present study was conducted to compare the efficacy of Honey dressing versus Silver Sulfadiazine dressing for complete wound healing in the 2nd-degree thermal burn. Study Design: A Randomized controlled trial was carried out in the Department of General Surgery/burn unit of Ayub Teaching Hospital Abbottabad from July to December 2018. The study population included thermal burn patients presenting with ASA-I, ASA-II, and body surface area less than 50% of the age group above 12 to 60 years of either gender. All the patients were randomly divided into two equal groups of patients by blocked randomization using permuted block g 6. In group ‘A,’ patients underwent dressing by honey method, and patients in group ‘B’ had silver sulfadiazine dressing. The dressing was changed every 48 hours by a senior sur?geon, and the condition of the wound was observed. Time duration till complete wound healing was noted in the Proforma. Results: A total of 100 patients were selected and divided into two groups of 50 patients in each two groups. The mean age of the patients was 27.66±13.388 ran?ging from 12 to 60 years of age, and the mean duration of complete healing of wound in days was 20.20±6.251, ranging from 2 to 30 days. Mean comparison of age with both groups, age of the patients was 21.24±3.761 (n=50) in group ‘A,’ i.e., honey dressing, and 19.16±7.911 (n=50) was in group ‘B,’ i.e., silver sulfadiazine dressing. Efficacy in the honey dressing group was found effective in 48(75.0%) and ineffect? ive in 2(5.6%) out of 50 patients. Efficacy in silver sulfadiazine dressing group 16(25.0%) was three found effective and in 34(94.4%) was inef?fective out of 50 patients. There was a statistically significant difference between both groups. (P=0.000) . Conclusion: honey dressing is more effective as compared to silver sulfadiazine dressing in terms of complete wound healing in second-degree thermal burn patients; our study also concluded the same.

Keywords: efficacy, honey dressing, silver sulfadiazine dressing, wound healing

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Authors: Oscar Bautista, Jose Arcos

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In this work, we conduct a theoretical analysis of an oscillatory electroosmotic flow in a parallel-plate microchannel taking into account slippage at the microchannel walls. The governing equations given by the Poisson-Boltzmann (with the Debye-Huckel approximation) and momentum equations are nondimensionalized from which four dimensionless parameters appear; a Reynolds angular number, the ratio between the zeta potentials of the microchannel walls, the electrokinetic parameter and the dimensionless slip length which measures the competition between the Navier slip length and the half height microchannel. The principal results indicate that the slippage has a strong influence on the magnitude of the oscillatory electroosmotic flow increasing the velocity magnitude up to 50% for the numerical values used in this work.

Keywords: electroosmotic flows, oscillatory flow, slippage, microchannel

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Authors: Victor Mantilla, Romeu Vicente, António Figueiredo, Victor Ferreira, Sandra Sorte

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Integrating dynamic facades into contemporary building design is shaping a new era of energy efficiency and user comfort. These innovative facades, often constructed using lightweight construction systems and materials, offer an opportunity to have a responsive and adaptive nature to the dynamic behavior of the outdoor climate. Therefore, in regions characterized by high fluctuations in daily temperatures, the ability to adapt to environmental changes is of paramount importance and a challenge. This paper presents a thorough review of the state of the art on double-skin facades (DSF), focusing on lightweight solutions for the external envelope. Dynamic facades featuring elements like movable shading devices, phase change materials, and advanced control systems have revolutionized the built environment. They offer a promising path for reducing energy consumption while enhancing occupant well-being. Lightweight construction systems are increasingly becoming the choice for the constitution of these facade solutions, offering benefits such as reduced structural loads and reduced construction waste, improving overall sustainability. However, the performance of dynamic facades based on low thermal inertia solutions in climatic contexts with high thermal amplitude is still in need of research since their ability to adapt is traduced in variability/manipulation of the thermal transmittance coefficient (U-value). Emerging technologies can enable such a dynamic thermal behavior through innovative materials, changes in geometry and control to optimize the facade performance. These innovations will allow a facade system to respond to shifting outdoor temperature, relative humidity, wind, and solar radiation conditions, ensuring that energy efficiency and occupant comfort are both met/coupled. This review addresses the potential configuration of double-skin facades, particularly concerning their responsiveness to seasonal variations in temperature, with a specific focus on addressing the challenges posed by winter and summer conditions. Notably, the design of a dynamic facade is significantly shaped by several pivotal factors, including the choice of materials, geometric considerations, and the implementation of effective monitoring systems. Within the realm of double skin facades, various configurations are explored, encompassing exhaust air, supply air, and thermal buffering mechanisms. According to the review places a specific emphasis on the thermal dynamics at play, closely examining the impact of factors such as the color of the facade, the slat angle's dimensions, and the positioning and type of shading devices employed in these innovative architectural structures.This paper will synthesize the current research trends in this field, with the presentation of case studies and technological innovations with a comprehensive understanding of the cutting-edge solutions propelling the evolution of building envelopes in the face of climate change, namely focusing on double-skin lightweight solutions to create sustainable, adaptable, and responsive building envelopes. As indicated in the review, flexible and lightweight systems have broad applicability across all building sectors, and there is a growing recognition that retrofitting existing buildings may emerge as the predominant approach.

Keywords: adaptive, control systems, dynamic facades, energy efficiency, responsive, thermal comfort, thermal transmittance

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Authors: Rajaian Hoonejani Mohammad, Eshraghi Pegah, Zomorodian Zahra Sadat, Tahsildoost Mohammad

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Over the past decade, energy consumption in educational buildings has steadily increased. The purpose of this research is to provide a method to quickly predict the energy consumption of buildings using separate evaluation of zones and decomposing the building to eliminate the complexity of geometry at the early design stage. To produce this framework, machine learning algorithms such as Support vector regression (SVR) and Artificial neural network (ANN) are used to predict energy consumption and thermal comfort metrics in a school as a case. The database consists of more than 55000 samples in three climates of Iran. Cross-validation evaluation and unseen data have been used for validation. In a specific label, cooling energy, it can be said the accuracy of prediction is at least 84% and 89% in SVR and ANN, respectively. The results show that the SVR performed much better than the ANN.

Keywords: early stage of design, energy, thermal comfort, validation, machine learning

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Authors: Bader Alkandari, Jamal Y. Madouh, Ahmad M. Alkandari, Anwar A. Alnaqi

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A new formulation of fuzzy linear estimation problem is presented. It is formulated as a linear programming problem. The objective is to minimize the spread of the data points, taking into consideration the type of the membership function of the fuzzy parameters to satisfy the constraints on each measurement point and to insure that the original membership is included in the estimated membership. Different models are developed for a fuzzy triangular membership. The proposed models are applied to different examples from the area of fuzzy linear regression and finally to different examples for estimating the electrical load on a busbar. It had been found that the proposed technique is more suited for electrical load estimation, since the nature of the load is characterized by the uncertainty and vagueness.

Keywords: fuzzy regression, load estimation, fuzzy linear parameters, electrical load estimation

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Authors: Omar M. Ben-Sasi

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Ductility of slab-column connections of flat slab structures is a desirable property that should be considered when designing such connections which are susceptible to punching failure around their columns. Tests to failure on six half-scale specimens were conducted for slab-interior column connections transferring shear force and unbalanced moment. The influences on connection ductility of four parameters; namely, the moment to shear force ratio, the ratio of column side length to slab effective depth, the aspect ratio of the column cross section, and the presence of four square openings located next to column corners were investigated. The study revealed marked effects of these parameters on connection ductility. Increasing the first and second parameters, were found to be in favor of increasing connection ductility, while the third and fourth parameters were found to have negative effects on the connection ductility. These findings should, hopefully, help in designing interior connections of flat slab structures.

Keywords: ductility, flat slab, failure, shear force, moment, unbalanced moment, punching failure, connection, interior-column connection

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Authors: S. Khardazi, H. Zaitouni, A. Neqali, S. Lyubchyk, D. Mezzane, M. Amjoud, E. Choukri, S. Lyubchyk, Z. Kutnjak

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In the present paper, structural, dielectric, ferroelectric, and energy storage properties of pure perovskite lead-free BCZT, BTSn, and BTSn-BCZT ferroelectric ceramics have been investigated. Rietveld refinement of XRD data confirms the coexistence of the rhombohedral and orthorhombic phases at room temperature in the composite BCZT–BTSn ceramic. Remarkably, an improved recoverable energy density of 137.86 mJ/cm³ and a high energy storage efficiency of 86.19 % at 80°C under a moderate applied electric field of 30 kV/cm were achieved in the designed BCZT–BTSn ceramic. Besides, the sample exhibits excellent thermal stability of the energy storage efficiency (less than 3%) in the temperature range of 70 to 130 °C under 30 kV/cm. Such results make the pb-free BCZT–BTSn ferroelectric ceramic a very promising potential matrix for energy storage capacitor applications.

Keywords: sol-gel, ferroelectrics, lead-free, perovskites, energy storage

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Authors: Merouane Salhi, Toufik Zebbiche

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When the stagnation pressure of perfect gas increases, the specific heat and their ratio do not remain constant anymore and start to vary with this pressure. The gas doesn’t remain perfect. Its state equation change and it becomes for a real gas. In this case, the effects of molecular size and intermolecular attraction forces intervene to correct the state equation. The aim of this work is to show and discuss the effect of stagnation pressure on supersonic thermodynamical, physical and geometrical flow parameters, to find a general case for real gas. With the assumptions that Berthelot’s state equation accounts for the molecular size and intermolecular force effects, expressions are developed for analyzing supersonic flow for thermally and calorically imperfect gas lower than the dissociation molecules threshold. The designs parameters for supersonic nozzle like thrust coefficient depend directly on stagnation parameters of the combustion chamber. The application is for air. A computation of error is made in this case to give a limit of perfect gas model compared to real gas model.

Keywords: supersonic flow, real gas model, Berthelot’s state equation, Simpson’s method, condensation function, stagnation pressure

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Authors: K. Y. S. Putri, Heri Fathurahman, Yuki Surisita, Widi Sagita, Kiki Dwi Arviani

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Society needs the assistance of academics in understanding and being skilled in health communication literacy. Information technology runs very fast while health communication literacy skills in getting health communication information during the pandemic are not as fast as the development of information technology. The research question is whether there is an influence of health communication on information technology in health information during the pandemic in Indonesia. The purpose of the study is to find out the influence of health communication on information technology in health information during the pandemic in Indonesia. The concepts of health communication literacy and information technology are used this study. Previous research is in support of this study. Quantitative research methods by disseminating questionnaires in this study. The validity and reliability test of this study is positive, so it can proceed to the next statistical analysis. Descriptive results of variable health communication literacy are of positive value in all dimensions. All dimensions of information technology are of positive value. Statistical tests of the influence of health communication literacy on information technology are of great value. Discussion of both variables in the influence of health communication literacy and high-value information technology because health communication literacy has a high effect in information technology. Respondents to this study have high information technology skills. So that health communication literacy in obtaining health information during the 2019-2022 pandemic is needed. Research advice is that academics are still very much needed by the community in the development of society during the pandemic.

Keywords: health information, health information needs, literacy health communication, information technology

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Authors: Jaqueline G. L. Cosme, Paulo H. S. Picciani, Regina C. R. Nunes

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Electrospinning is a technique for the fabrication of nanoscale fibers. The general electrospinning system consists of a syringe filled with polymer solution, a syringe pump, a high voltage source and a grounded counter electrode. During electrospinning a volumetric flow is set by the syringe pump and an electric voltage is applied. This forms an electric potential between the needle and the counter electrode (collector plate), which results in the formation of a Taylor cone and the jet. The jet is moved towards the lower potential, the counter electrode, wherein the solvent of the polymer solution is evaporated and the polymer fiber is formed. On the way to the counter electrode, the fiber is accelerated by the electric field. The bending instabilities that occur form a helical loop movements of the jet, which result from the coulomb repulsion of the surface charge. Trough bending instabilities the jet is stretched, so that the fiber diameter decreases. In this study, a thermoplastic/elastomeric binary blend of non-vulcanized epoxidized natural rubber (ENR) and poly(latic acid) (PLA) was electrospun using polymer solutions consisting of varying proportions of PCL and NR. Specifically, 15% (w/v) PLA/ENR solutions were prepared in /chloroform at proportions of 5, 10, 25, and 50% (w/w). The morphological and thermal properties of the electrospun mats were investigated by scanning electron microscopy (SEM) and differential scanning calorimetry analysis. The SEM images demonstrated the production of micrometer- and sub-micrometer-sized fibers with no bead formation. The blend miscibility was evaluated by thermal analysis, which showed that blending did not improve the thermal stability of the systems.

Keywords: epoxidized natural rubber, poly(latic acid), electrospinning, chemistry

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Authors: Yuchen Yang, Zhenming Wang, Jun Zhu, Ning Zhao

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An easy-to-implement and robust finite volume multi-resolution Weighted Essentially Non-Oscillatory (WENO) scheme is proposed on adaptive cartesian grids in this paper. Such a multi-resolution WENO scheme is combined with the ghost cell immersed boundary method (IBM) and wall-function technique to solve Navier-Stokes equations. Unlike the k-exact finite volume WENO schemes which involve large amounts of extra storage, repeatedly solving the matrix generated in a least-square method or the process of calculating optimal linear weights on adaptive cartesian grids, the present methodology only adds very small overhead and can be easily implemented in existing edge-based computational fluid dynamics (CFD) codes with minor modifications. Also, the linear weights of this adaptive finite volume multi-resolution WENO scheme can be any positive numbers on condition that their sum is one. It is a way of bypassing the calculation of the optimal linear weights and such a multi-resolution WENO scheme avoids dealing with the negative linear weights on adaptive cartesian grids. Some benchmark viscous problems are numerical solved to show the efficiency and good performance of this adaptive multi-resolution WENO scheme. Compared with a second-order edge-based method, the presented method can be implemented into an adaptive cartesian grid with slight modification for big Reynolds number problems.

Keywords: adaptive mesh refinement method, finite volume multi-resolution WENO scheme, immersed boundary method, wall-function technique.

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Authors: Haibo Sheng, Yuan Hu

Abstract:

Spinel structure Zinc stannate (Zn2SnO4, ZS)/Graphene was successfully synthesized by a simple in situ hydrothermal route. Morphological study and structure analysis confirmed the homogenously loading of ZS on the graphene sheets. Then, the resulted ZS/graphene hybrids were incorporated into epoxy resin to form EP/ZS/graphene composites by a solvent dispersion method. Improved thermal stability was investigated by Thermogravimetric Analysis (TGA). Cone calorimeter result showed low peak heat release rate (PHRR). Toxical gases release during combustion was evaluated by a facile device organized in our lab. The results showed that the release of NOx, HCN decrease of about 55%. Also, TG-IR technology was used to investigate the gas release during the EP decomposition process. The CO release had decreased about 80%.The EP/G/ZS showed lowest hazards during combustion (including flame retardancy, thermal stability, lower toxical gases release and so on) than pure EP.

Keywords: fire hazards, zinc stannate, epoxy resin, toxical gas hazards

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Authors: Pranudda Pimsee, Caroline Sablayrolles, Pascale De Caro, Julien Guyomarch, Nicolas Lesage, Mireille Montréjaud-Vignoles

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The MIGR’HYCAR research project was initiated to provide decisional tools for risks connected to oil spill drifts in continental waters. These tools aim to serve in the decision-making process once oil spill pollution occurs and/or as reference tools to study scenarios of potential impacts of pollutions on a given site. This paper focuses on the study of the distribution of polycyclic aromatic hydrocarbons (PAHs) and derivatives from oil spill in water as function of environmental parameters. Eight petroleum oils covering a representative range of commercially available products were tested. 41 Polycyclic Aromatic Hydrocarbons (PAHs) and derivate, among them 16 EPA priority pollutants were studied by dynamic tests at laboratory scale. The chemical profile of the water soluble fraction was different from the parent oil profile due to the various water solubility of oil components. Semi-volatile compounds (naphtalenes) constitute the major part of the water soluble fraction. A large variation in composition of the water soluble fraction was highlighted depending on oil type. Moreover, four environmental parameters (temperature, suspended solid quantity, salinity, and oil: water surface ratio) were investigated with the Taguchi experimental design methodology. The results showed that oils are divided into three groups: the solubility of Domestic fuel and Jet A1 presented a high sensitivity to parameters studied, meaning they must be taken into account. For gasoline (SP95-E10) and diesel fuel, a medium sensitivity to parameters was observed. In fact, the four others oils have shown low sensitivity to parameters studied. Finally, three parameters were found to be significant towards the water soluble fraction.

Keywords: mornitoring, PAHs, water soluble fraction, SBSE, Taguchi experimental design

Procedia PDF Downloads 305