Search results for: runoff coefficient

Authors: Sara Taghdisi, M. Mirmohammadi, M. Mokhtarian

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In 2013, the World Health Organization announced the cases of Cutaneous leishmaniasis infection in Iran between 69,000 to 113,000. The most common chemical drugs for Cutaneous leishmaniasis treatment are sodium stibogluconate, and meglumine antimonate, which not only have relatively many side effects, but also some species of the Leishmania genus have become resistant to them .The most prominent compound existing in different parts of the cotton plant is a yellow polyphenol called Gossypol. Gossypol is an extremely valuable compound and has anti-cancer properties. In the current project, Gossypol was extracted with a liquid-liquid extraction method in 120 minutes in the presence of Phosphoric acid from the cotton seed oil of Golestan beach varieties, then got crystallized in darkness using Acetic acid and isolated as Gossypol Acetic acid. The efficiency of the extracted crystal was obtained at 0.12+- 1.28. the cotton plant could be efficient in the treatment of Cutaneous leishmaniasis. The extract of the green-leaf cotton boll of Jargoyeh varieties was tested as an ointment on the target group of patients suffering from Cutaneous leishmaniasis resistant to drugs esistant to drugs by our colleagues in the research team. The results showed the Pearson's correlation coefficient of 0.72 between the two variables of wound diameter and the extract use over time which indicated the positive effect of this extract on the treatment of Cutaneous leishmaniasis was resistant to drugs.

Keywords: cottonseed oil, crystallization, gossypol, green-leaf

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Authors: Atwari Rawani, Suresh Prasad Sharma, K. D. P. Singh

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In this paper, an analytical investigation based on energy and exergy analysis of the parabolic trough collector (PTC) with alternate clockwise and counter-clockwise twisted tape inserts in the absorber tube has been presented. For fully developed flow under quasi-steady state conditions, energy equations have been developed in order to analyze the rise in fluid temperature, thermal efficiency, entropy generation and exergy efficiency. Also the effect of system and operating parameters on performance have been studied. A computer program, based on mathematical models is developed in C++ language to estimate the temperature rise of fluid for evaluation of performances under specified conditions. For numerical simulations four different twist ratio, x = 2,3,4,5 and mass flow rate 0.06 kg/s to 0.16 kg/s which cover the Reynolds number range of 3000 - 9000 is considered. This study shows that twisted tape inserts when used shows great promise for enhancing the performance of PTC. Results show that for x=1, Nusselt number/heat transfer coefficient is found to be 3.528 and 3.008 times over plain absorber of PTC at mass flow rate of 0.06 kg/s and 0.16 kg/s respectively; while corresponding enhancement in thermal efficiency is 12.57% and 5.065% respectively. Also the exergy efficiency has been found to be 10.61% and 10.97% and enhancement factor is 1.135 and 1.048 for same set of conditions.

Keywords: exergy efficiency, twisted tape ratio, turbulent flow, useful heat gain

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Authors: Jitendra Narayan Panda, Jayashree Bijwe, Raj K. Pandey

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PAEK (Polyaryl ether ketone) being a high-performance polymer, is currently being explored for its tribo-potential by incorporating various fibers, solid lubricants. In this work, influence of amount (30 and 40 %) of short glass fibers (GF) in two composites containing PAEK (60 and 50 %) and synthetic graphite (10 %) on mechanical and tribological behaviour was studied. The composites were developed by injection molding and evaluated in adhesive wear mode (pin on disc configuration) against mild steel disc. The load and speed were selected as variable input parameters while coefficient of friction (µ), specific wear rate (K0) and PVlimit (pressure × velocity) values were selected as output parameters for performance evaluation. Although higher amount of GF lead to better mechanical properties, tribological properties were not in tune to this. Overall, µ and K0 for both composites were in the range 0.04-0.08 and 3-8x 10-16 m3/Nm respectively and decreased with increase in applied PV values till failure was observed. PVlimit was indicated by 112 and 100 MPa m/s. Such high PVlimit values are not reported for any polymer composites running in dry conditions in the literature. The mechanical properties of the C40 composite (40 % GF) proved superior to C30 composite (30 % GF). However, all tribological properties of C40 were inferior to C30. It exhibited higher µ, higher K0 and slightly lower PVlimit value. The higher % fibers proved detrimental for tribo-performance and worn surface analysis by SEM & EDAX was done on the discs & pins to understand wear mechanisms.

Keywords: PAEK composites, pin-on-disk, PV limit, friction

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Authors: S. Jain, R. Savalia, V. Saini

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A simple, accurate, precise, sensitive and specific RP-HPLC method was developed and validated for simultaneous estimation of Metoprolol Succinate and Olmesartan Medoxomil in bulk and tablet dosage form. The RP-HPLC method has shown adequate separation for Metoprolol Succinate and Olmesartan Medoxomil from its degradation products. The separation was achieved on a Phenomenex luna ODS C18 (250mm X 4.6mm i.d., 5μm particle size) with an isocratic mixture of acetonitrile: 50mM phosphate buffer pH 4.0 adjusted with glacial acetic acid in the ratio of 55:45 v/v. The mobile phase at a flow rate of 1.0ml/min, Injection volume 20μl and wavelength of detection was kept at 225nm. The retention time for Metoprolol Succinate and Olmesartan Medoxomil was 2.451±0.1min and 6.167±0.1min, respectively. The linearity of the proposed method was investigated in the range of 5-50μg/ml and 2-20μg/ml for Metoprolol Succinate and Olmesartan Medoxomil, respectively. Correlation coefficient was 0.999 and 0.9996 for Metoprolol Succinate and Olmesartan Medoxomil, respectively. The limit of detection was 0.2847μg/ml and 0.1251μg/ml for Metoprolol Succinate and Olmesartan Medoxomil, respectively and the limit of quantification was 0.8630μg/ml and 0.3793μg/ml for Metoprolol and Olmesartan, respectively. Proposed methods were validated as per ICH guidelines for linearity, accuracy, precision, specificity and robustness for estimation of Metoprolol Succinate and Olmesartan Medoxomil in commercially available tablet dosage form and results were found to be satisfactory. Thus the developed and validated stability indicating method can be used successfully for marketed formulations.

Keywords: metoprolol succinate, olmesartan medoxomil, RP-HPLC method, validation, ICH

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Authors: E. O. Echeweozo

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This study evaluated radiation shielding and interaction characteristics of polyvinyl alcohol (PVA) polymer separately doped with 10% and 20% nanoscale Bi₂O₃, respectively, for medical apron design and shielding special electronic installations. Prepared samples were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS). The EDS results showed that Carbon (C), Oxygen (O), and bismuth (Bi) elements were the predominant elements present in the prepared samples. The SEM result displaced surface irregularities due to a special bonding matrix between PVA and Bi₂O₃. Mass attenuation coefficient (MAC), effective atomic number (Zeff), Half value layer (HVL), Mean free path (MFP), Fast neutron removal cross-section (R), Total Mass Stopping Power (TSP), and photon Range (R) of the prepared polymer composites (PV-1Bi and PV-2Bi) were evaluated with XCOM and PHITS computer programs. Results showed that the MAC of the prepared polymer samples was significantly higher than some recently developed composites at 0.662MeV and 1.25MeV gamma energy. Therefore, polyvinyl alcohol (PVA) polymer doped with Bi₂O₃ should be deployed in medical apron design and shielding special electronic installations where flexibility and high adhesion ability are crucial.

Keywords: polyvinyl alcohol (PVA);, polymer composite, gamma-rays, charged particles

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Authors: Mamta Rana, K. K. Singh, Nisha Kumari

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The simulation models with its soil-weather-plant atmosphere interacting system are important tools for assessing the crops in changing climate conditions. The CERES-Wheat & Rice vs. 4.6 DSSAT was calibrated and evaluated for one of the major producers of wheat and rice state- Haryana, India. The simulation runs were made under irrigated conditions and three fertilizer applications dose of N-P-K to estimate crop yield and other growth parameters along with the phenological development of the crop. The genetic coefficients derived by iteratively manipulating the relevant coefficients that characterize the phenological process of wheat and rice crop to the best fit match between the simulated and observed anthesis, physological maturity and final grain yield. The model validated by plotting the simulated and remote sensing derived LAI. LAI product from remote sensing provides the edge of spatial, timely and accurate assessment of crop. For validating the yield and yield components, the error percentage between the observed and simulated data was calculated. The analysis shows that the model can be used to simulate crop yield and yield components for wheat and rice cultivar under different management practices. During the validation, the error percentage was less than 10%, indicating the utility of the calibrated model for climate risk assessment in the selected region.

Keywords: simulation model, CERES-wheat and rice model, crop yield, genetic coefficient

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Authors: Esmail Sadipour

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The use of social networks is increasing day by day in all societies. The purpose of this research was to know the relationship between the use of social networks (Instagram, WhatsApp, and Telegram) with executive functions and academic performance in first-year female high school students. This research was applied in terms of purpose, quantitative in terms of data type, and correlational in terms of technique. The population of this research consisted of all female high school students in the first year of district 2 of Tehran. Using Green's formula, the sample size of 150 people was determined and selected by cluster random method. In this way, from all 17 high schools in district 2 of Tehran, 5 high schools were selected by a simple random method and then one class was selected from each high school, and a total of 155 students were selected. To measure the use of social networks, a researcher-made questionnaire was used, the Barclay test (2012) was used for executive functions, and last semester's GPA was used for academic performance. Pearson's correlation coefficient and multivariate regression were used to analyze the data. The results showed that there is a negative relationship between the amount of use of social networks and self-control, self-motivation and time self-management. In other words, the more the use of social networks, the fewer executive functions of students, self-control, self-motivation, and self-management of their time. Also, with the increase in the use of social networks, the academic performance of students has decreased.

Keywords: social networks, executive function, academic performance, working memory

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Authors: N. K. Ambujam, V. Sudha

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Reservoirs are being contaminated all around the world with point source and Non-Point Source (NPS) pollution. The most common NPS pollutants are sediments and nutrients. Krishnagiri Reservoir (KR) has been chosen for the present case study, which is located in the tropical semi-arid climatic zone of Tamil Nadu, South India. It is the main source of surface water in Krishnagiri district to meet the freshwater demands. The reservoir has lost about 40% of its water holding capacity due to sedimentation over the period of 50 years. Hence, from the research and management perspective, there is a need for a sound knowledge on the spatial and seasonal variations of KR water quality. The present study encompasses the specific objectives as (i) to investigate the longitudinal heterogeneity and seasonal variations of physicochemical parameters, nutrients and biological characteristics of KR water and (ii) to examine the extent of degradation of water quality in KR. 15 sampling points were identified by uniform stratified method and a systematic monthly sampling strategy was selected due to high dynamic nature in its hydrological characteristics. The physicochemical parameters, major ions, nutrients and Chlorophyll a (Chl a) were analysed. Trophic status of KR was classified by using Carlson's Trophic State Index (TSI). All statistical analyses were performed by using Statistical Package for Social Sciences programme, version-16.0. Spatial maps were prepared for Chl a using Arc GIS. Observations in KR pointed out that electrical conductivity and major ions are highly variable factors as it receives inflow from the catchment with different land use activities. The study of major ions in KR exhibited different trends in their values and it could be concluded that as the monsoon progresses the major ions in the water decreases or water quality stabilizes. The inflow point of KR showed comparatively higher concentration of nutrients including nitrate, soluble reactive phosphorus (SRP), total phosphors (TP), total suspended phosphorus (TSP) and total dissolved phosphorus (TDP) during monsoon seasons. This evidently showed the input of significant amount of nutrients from the catchment side through agricultural runoff. High concentration of TDP and TSP at the lacustrine zone of the reservoir during summer season evidently revealed that there was a significant release of phosphorus from the bottom sediments. Carlson’s TSI of KR ranged between 81 and 92 during northeast monsoon and summer seasons. High and permanent Cyanobacterial bloom in KR could be mainly due to the internal loading of phosphorus from the bottom sediments. According to Carlson’s TSI classification Krishnagiri reservoir was ranked in the hyper-eutrophic category. This study provides necessary basic data on the spatio-temporal variations of water quality in KR and also proves the impact of point and NPS pollution from the catchment area. High TSI warrants a greater threat for the recovery of internal P loading and hyper-eutrophic condition of KR. Several expensive internal measures for the reduction of internal loading of P were introduced by many scientists. However, the outcome of the present research suggests for the innovative algae harvesting technique for the removal of sediment nutrients.

Keywords: NPS pollution, nutrients, hyper-eutrophication, krishnagiri reservoir

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Authors: Nikhil S. Mane, Mukund L. Harugade, Narayan V. Hargude, Vishal P. Patil

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The fluids exposed to magnetic field can enhance the convective heat transfer by inducing secondary convection currents due to Lorentz force. The use of magnetohydrodynamic (MHD) forces in power generation and mass transfer is increasing steadily but its application to enhance the convective currents in fluids needed to be explored. The enhancement in convective heat transfer using MHD forces can be employed in heat exchangers, cooling of molten metal, vapour compression refrigeration (VCR) systems etc. The effective increase in the convective heat transfer without any additional energy consumption will lead to the energy efficient heat exchanging devices. In this work, the effect of MHD forces on the performance of air conditioning system working on the VCR system is studied. The refrigerant in VCR system is exposed to the magnetic field which influenced the flow of refrigerant. The different intensities of magnets are used on the different liquid refrigerants and investigation on performance of split air conditioning system is done under different loading conditions. The results of this research work show that the application of magnet on refrigerant flow has positive influence on the coefficient of performance (COP) of split air conditioning system. It is also observed that with increasing intensity of magnetic force the COP of split air conditioning system also increases.

Keywords: magnetohydrodynamics, heat transfer enhancement, VCRS, air conditioning, refrigeration

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Authors: Tesfay Mekonnen Weldegerima

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Analysis of precipitation time series is a fundamental undertaking in meteorology and hydrology. The extreme precipitation scenario of the Kulfo River watershed is studied using wavelet analysis and atmospheric transport, a lagrangian trajectory model. Daily rainfall data for the 1991-2020 study periods are collected from the office of the Ethiopian Meteorology Institute. Meteorological fields on a three-dimensional grid at 0.5o x 0.5o spatial resolution and daily temporal resolution are also obtained from the Global Data Assimilation System (GDAS). Wavelet analysis of the daily precipitation processed with the lag-1 coefficient reveals some high power recurred once every 38 to 60 days with greater than 95% confidence for red noise. The analysis also identified inter-annual periodicity in the periods 2002 - 2005 and 2017 - 2019. Back trajectory analysis for 3-day periods up to May 19/2011, indicates the Indian Ocean source; trajectories crossed the eastern African escarpment to arrive at the Kulfo watershed. Atmospheric flows associated with the Western Indian monsoon redirected by the low-level Somali winds and Arabian ridge are responsible for the moisture supply. The time-localization of the wavelet power spectrum yields valuable hydrological information, and the back trajectory approaches provide useful characterization of air mass source.

Keywords: extreme precipitation events, power spectrum, back trajectory, kulfo watershed

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Authors: Sanjeet Kumar Singh, Shantanu Bhatacharya

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Design of high-efficiency low, frequency (<1000Hz) soundproof window or wall absorber which is transparent to airflow is presented. Due to the massive rise in human population and modernization, environmental noise has significantly risen globally. Prolonged noise exposure can cause severe physiological and psychological symptoms like nausea, headaches, fatigue, and insomnia. There has been continuous growth in building construction and infrastructure like offices, bus stops, and airports due to the urban population. Generally, a ventilated window is used for getting fresh air into the room, but at the same time, unwanted noise comes along. Researchers used traditional approaches like noise barrier mats in front of the window or designed the entire window using sound-absorbing materials. However, this solution is not aesthetically pleasing, and at the same time, it's heavy and not adequate for low-frequency noise shielding. To address this challenge, we design a transparent hexagonal panel based on the Sierpiński fractal triangle, which is aesthetically pleasing and demonstrates a normal incident sound absorption coefficient of more than 0.96 around 700 Hz and transmission loss of around 23 dB while maintaining e air circulation through the triangular cutout. Next, we present a concept of fabrication of large acoustic panels for large-scale applications, which leads to suppressing urban noise pollution.

Keywords: acoustic metamaterials, ventilation, urban noise pollution, noise control

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Authors: Franklin Nantui Mabe, Gideon Danso-Abbeam, Dennis Sedem Ehiakpor

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In order for the government of Ghana through the Ministry of Food and Agriculture to motivate farmers to adopt improved agricultural technologies, expand their farms and encourage youth to enter into agricultural production so as to increase crop productivity, “Planting for Food and Jobs” (PFJ) programme was launched in April 2017. The PFJ programme covers five pillars, namely, provision of subsidized and improved seeds; subsidized fertilizer; agricultural extension services; establishment of markets; and e-agriculture. This study assesses the awareness of farmers about the packages of these pillars using the Likert scale, paired t-test and Spearman’s rank correlation coefficient. The study adopted a mixed research design. A semi-structured questionnaire and checklist were used to collect data. The data collection was done using interviews and focus group discussions. The PFJ pillar farmers are much aware is a subsidy on fertilizer followed by a subsidy on improved seeds. Electronic agriculture is a pillar with the lowest level of awareness. There is a strong positive correlation between awareness of fertilizer and seed packages suggestion their complementarities. Lack of information/awareness of the packages of the programme can affect farmers’ participation in all the pillars. Farmers, in particular, should be educated for them to know what they are entitled to in each of the pillars. The programme implementation plan should also be made available to farmers as a guide.

Keywords: awareness, planting for food and jobs, programme, farmers, likert scale

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Authors: Azita Behbahaninia

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This research has been carried out to determine the water quality and physico-chemical properties Polour River, one of the most branch of Haraz River. Polour River was studied for a period of one year Samples were taken from different stations along the main branch of River polour. In water samples determined pH, DO, SO4, Cl, PO4, NO3, EC, BOD, COD, Temprature, color and number of Caliform per liter. ArcGIS was used for the zoning of phosphate concentration in the polour River basin. The results indicated that the river is polluted in polour village station, because of discharge domestic wastewater and also river is polluted in Ziar village station, because of agricultural wastewater and water is contaminated in aquaculture station, because of fish ponds wastewater. Statistical analysis shows that between independent traits and coliform regression relationship is significant at the 1% level. Coefficient explanation index indicated independent traits control 80% coliform and 20 % is for unknown parameters. The causality analysis showed Temperature (0.6) has the most positive and direct effect on coliform and sulfate has direct and negative effect on coliform. The results of causality analysis and the results of the regression analysis are matched and other forms direct and indirect effects were negligible and ignorable. Kruskal-Wallis test showed, there is different between sampling stations and studied characters. Between stations for temperature, DO, COD, EC, sulfate and coliform is at 1 % and for phosphate 5 % level of significance.

Keywords: coliform, GIS, pollution, phosphate, river

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Authors: Ould Mohamed Cheikh, Mounir Chaik, Hind El Aakib, Mohamed Aggour, Abdelkader Outzourhit

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Zinc sulfide [ZnS] and oxygenated zinc sulfide Zn(O,S) thin films were deposited on glass substrates, by reactive cathodic radio-frequency (RF) sputtering. The substrates power and percentage of oxygen were varied in the range of 100W to 250W and from 5% to 20% respectively. The structural, morphological and optical properties of these thin films were investigated. The optical properties (mainly the refractive index, absorption coefficient and optical band gap) were examined by optical transmission measurements in the ultraviolet-visible-near Infrared wavelength range. XRD analysis indicated that all sputtered ZnS films were a single phase with a preferential orientation along the (111) plane of zinc blend (ZB). The crystallite size was in the range of 19.5 nm to 48.5 nm, the crystallite size varied with RF power reaching a maximum at 200 W. The Zn(O,S) films, on the other hand, were amorphous. UV-Visible, measurements showed that the ZnS film had more than 80% transmittance in the visible wavelength region while that of Zn(O,S is 85%. Moreover, it was observed that the band gap energy of the ZnS films increases slightly from 3.4 to 3.52 eV as the RF power was increased. The optical band gap of Zn(O,S), on the other hand, decreased from 4.2 to 3.89 eV as the oxygen partial pressure is increased in the sputtering atmosphere at a fixed RF-power. Scanning electron microscopy observations revealed smooth surfaces for both type of films. The X-ray reflectometry measurements on the ZnS films showed that the density of the films (3.9 g/cm3) is close that of bulk ZnS.

Keywords: thin films Zn(O, S) properties, Zn(O, S) by Rf-sputtering, ZnS for solar cells, thin films for renewable energy

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Authors: C. J. Coetzee, E. Horn

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One of the main challenges in using the Discrete Element Method (DEM) is to specify the correct input parameter values. In general, the models are sensitive to the input parameter values and accurate results can only be achieved if the correct values are specified. For the linear contact model, micro-parameters such as the particle density, stiffness, coefficient of friction, as well as the particle size and shape distributions are required. There is a need for a procedure to accurately calibrate these parameters before any attempt can be made to accurately model a complete bulk materials handling system. Since DEM is often used to model applications in the mining and quarrying industries, a calibration procedure was developed for materials that consist of relatively large (up to 40 mm in size) particles. A coarse crushed aggregate was used as the test material. Using a specially designed large shear box with a diameter of 590 mm, the confined Young’s modulus (bulk stiffness) and internal friction angle of the material were measured by means of the confined compression test and the direct shear test respectively. DEM models of the experimental setup were developed and the input parameter values were varied iteratively until a close correlation between the experimental and numerical results was achieved. The calibration process was validated by modelling the pull-out of an anchor from a bed of material. The model results compared well with experimental measurement.

Keywords: Discrete Element Method (DEM), calibration, shear box, anchor pull-out

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Authors: Magdalena Suśniak, Joanna Karwan-Baczewska

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Microstructure and tribological properties of AlSi5Cu2 matrix composite reinforced with SiC have been studied by microscopic examination and basic tribological properties. Composite material was produced by the mechanical alloying and spark plasma sintering (SPS) technique. The mixture of AlSi5Cu2 chips with 0, 10, 15 wt. % of SiC powder were placed in 250 ml mixing jar and milled 40 hours. To prevent the extreme cold welding the 1 wt. % of stearic acid was added to the powder mixture as a process control agent. Mechanical alloying provide to obtain composites powder with uniform distribution of SiC in matrix. Composite powders were poured into a graphite and a pulsed electric current was passed through powder under vacuum to consolidate material. Processing conditions were: sintering temperature 450°C, uniaxial pressure 32MPa, time of sintering 5 minutes. After SPS process composite samples indicate higher hardness values, lower weight loss, and lower coefficient of friction as compared with the unreinforced alloy. Light microscope micrograph of the worn surfaces and wear debris revealed that in the unreinforced alloy the prominent wear mechanism was the adhesive wear. In the AlSi5Cu2/SiC composites, by increasing of SiC the wear mechanism changed from adhesive and micro-cutting to abrasive and delamination for composite with 20 SiC wt. %. In all the AlSi5Cu2/SiC composites, abrasive wear was the main wear mechanism.

Keywords: aluminum matrix composite, mechanical alloying, spark plasma sintering, AlSi5Cu2/SiC composite

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Authors: B. Moaveni, S. Morovati

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In recent years, increasing the usage of railway transportations especially in developing countries caused more attention to control systems railway vehicles. Consequently, designing and implementing the modern control systems to improve the operating performance of trains and locomotives become one of the main concerns of researches. Dynamic braking systems is an important safety system which controls the amount of braking torque generated by traction motors, to keep the adhesion coefficient between the wheel-sets and rail road in optimum bound. Adhesion force has an important role to control the braking distance and prevent the wheels from slipping during the braking process. Cascade control structure is one of the best control methods for the wide range of industrial plants in the presence of disturbances and errors. This paper presents cascade control structure based on two forward simple controllers with two feedback loops to control the slip ratio and braking torque. In this structure, the inner loop controls the angular velocity and the outer loop control the longitudinal velocity of the locomotive that its dynamic is slower than the dynamic of angular velocity. This control structure by controlling the torque of DC traction motors, tries to track the desired velocity profile to access the predefined braking distance and to control the slip ratio. Simulation results are employed to show the effectiveness of the introduced methodology in dynamic braking system.

Keywords: cascade control, dynamic braking system, DC traction motors, slip control

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Authors: J. S. Rudas, J. M. Gutiérrez Cabeza, A. Corz Rodríguez, L. M. Gómez, A. O. Toro

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The prediction of the wear rate of rubbing pairs has attracted the interest of many researchers for years. It has been recently proposed that the sliding wear rate can be inferred from the calculation of the energy rate dissipated by the tribological pair. In this paper some of the dissipative mechanisms present in a pin-on-disc configuration are discussed and both analytical and numerical calculations are carried out. Three dissipative mechanisms were studied: First, the energy release due to temperature gradients within the solid; second, the heat flow from the solid to the environment, and third, the energy loss due to abrasive damage of the surface. The Finite Element Method was used to calculate the dynamics of heat transfer within the solid, with the aid of commercial software. Validation the FEM model was assisted by virtual and laboratory experimentation using different operating points (sliding velocity and geometry contact). The materials for the experiments were Ti6Al4V alloy and Tungsten Carbide (WC-Co). The results showed that the sliding wear rate has a linear relationship with the energy dissipation flow. It was also found that energy loss due to micro-cutting is relevant for the system. This mechanism changes if the sliding velocity and pin geometry are modified though the degradation coefficient continues to present a linear behavior. We found that the less relevant dissipation mechanism for all the cases studied is the energy release by temperature gradients in the solid.

Keywords: degradation, dissipative mechanism, dry sliding, entropy, friction, wear

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Authors: Daodu Joshua Rotimi

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This study investigated the Efficacy of Self-Assessment Metacognitive Strategy on Academic performance in Energy Concepts among Upper Basic Science Students in Ankpa, Kogi State, Nigeria. The research design adopted for the study was a Quasi-experimental control group design which employed a pretest, posttest of the experimental and control groups. The population of the study consisted of one hundred and twenty-four (124) JSSII Students; sixty-five (65) for the experimental group and (59) for the control group. The instrument used for the study was the Energy Concept Performance Test (ECPT), with a reliability coefficient of 0.80. Two research questions were answered using descriptive statistics of mean and standard deviation, while two hypotheses were tested using a t-test at P≤0.05 level of significance. The findings of the study revealed that the use of the Self-Assessment Metacognitive Strategy has a positive effect on students’ performance in energy concepts among upper Basic Science Students leading to high academic performance; also, there is no significant difference in the mean Academic Performance scores between Male and Female students taught Energy Concept using Self-Assessment Metacognitive Strategy. Based on the research findings, recommendations were made, which include that Secondary school teachers should be encouraged the use Self-Assessment Metacognitive strategy so as to make the learning process attractive, interactive and enriching to the learners.

Keywords: metacognition, self-assessment, performance, efficacy

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Authors: Priyanka Sharma, Tarkewshwar Dubey, Hemalatha Siva

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Hemorrhoids are one of the most common anorectal diseases around the world. Severalfactors are involved in causing hemorrhoids including irregularbowel function (constipation, diarrhea), exercise, gravity, low fiberdiet, pregnancy, obesity, high abdominal pressure, prolongedsitting, genetic factors, and aging. Pain, bleeding, itching,swelling and anal discharge are the symptoms of the disease. Due to limitedmodern pharmacotherapeutic options available for treatment, theherbal medicines remain the choice of therapy. Blumea lacera (Burm f.) DC. belonging to the Asteraceae family is a common plain land weed of Bangladesh. Traditionally it has been used for treatment of hemorrhoids.Considering the above fact, present study was aimed to validate the ethnomedicinal use of B. lacera leaves on experimental hemorrhoids in rats. The anti-hemorrhoid activity was performed by using croton oil induced rat models. The parameters studied were assessment of TNF-α and IL-6, Evans blue exudation, macroscopic severity score, recto-anal coefficient, histomorphological scores. Also, in vivo antioxidant parameters and histopathological studies were also performed. All paramaters exhibited significant anti-hemorrhoid activity. Moreover ethanolic extract of B. lacera (EBL) leaves 400mg/kg showed ameliorative effect oncroton oil induced hemorrhoids.In conclusion, EBL exhibitedbeneficial effect on croton oil- induced hemorrhoids and validates its ethnomedicinal use in treatment of piles.

Keywords: haemorrhoids, IL-6, piles, TNF-α

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Authors: Siphat Lim

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This study used Autoregressive Distributed Lag (ARDL) approach to cointegration. In the long-run the general price level and exchange rate have a positively significant effect on domestic output. The estimated result further revealed that fiscal stimulus help stimulate domestic output in the long-run, but not in the short-run, while monetary expansion help to stimulate output in both short-run and long-run. The result is complied with the theory which is the macroeconomic policies, fiscal and monetary policy; help to stimulate domestic output in the long-run. The estimated result of the Vector Error Correction Model (VECM) has indicated more clearly that the consumer price index has a positive effect on output with highly statistically significant. Increasing in the general price level would increase the competitiveness among producers than increase in the output. However, the exchange rate also has a positive effect and highly significant on the gross domestic product. The exchange rate depreciation might increase export since the purchasing power of foreigners has increased. More importantly, fiscal stimulus would help stimulate the domestic output in the long-run since the coefficient of government expenditure is positive. In addition, monetary expansion would also help stimulate the output and the result is highly significant. Thus, fiscal stimulus and monetary expansionary would help stimulate the domestic output in the long-run in Cambodia.

Keywords: fiscal policy, monetary policy, ARDL, VECM

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Authors: Shahrzad Yektatalab, Agrin Mohammadi, Ladan Zarshenas

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Background: Misophonia is a severe emotional response to repetitive sounds. This disorder may limit a person's communication, reduce their ability, or disrupt their social and personal life. This study aims to determine the prevalence of Misophonia and its relationship with obsessive-compulsive disorder, anxiety, and depression in undergraduate students of XXX University of Medical Sciences. Methods: The present study is an analytical descriptive study conducted in October 2020. The study samples are 390 undergraduate students of XXX University of medical sciences. A relative and systematic sampling method was used. In this study, a demographic questionnaire, misophonia questionnaire (A score of 7 or higher is considered as misophonia), Beck anxiety questionnaire, Beck depression questionnaire, and Maudsley questionnaire were used, and the data were analyzed using SPSS 24 software. Due to the non-normality of the data, the Spearman correlation coefficient was used for analyzing data. The significance level was considered less than 0.05. Results: 23.8% of students have misophonia. Of the 390 participants in the study, 93 had experienced misophonia. Among these 93 students, 37 (39.8%) had obsessive-compulsive disorder, 8 (8.6%) had anxiety and 9 (9.7%) had depression. There was a significant and direct relationship between all variables (p <0.001), which means that with the increase of each disorder, the probability of an increase in other disorders increases. Conclusion: Due to the high prevalence of misophonia in students and its direct relationship with obsessive-compulsive disorder, anxiety, and depression, It is recommended that future studies be conducted to identify ways to prevent and reduce the incidence of misophonia.

Keywords: misophonia, obsessive-compulsive disorder, anxiety, depression

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Authors: Ouahiba Taamallah, Tarek Litim

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The study deals with the burnishing effect of AISI 52100 steel and parameters influence (Py, i and f on surface integrity. The results show that the optimal effects are closely related to the treatment parameters. With a 92% improvement in roughness, SB can be defined as a finishing operation within the machining range. Due to 85% gain in consolidation rate, this treatment constitutes an efficient process for work-hardening of material. In addition, a statistical study based on regression and Taguchi's design has made it possible to develop mathematical models to predict output responses according to the studied burnishing parameters. Response Surface Methodology RSM showed a simultaneous influence of the burnishing parameters and to observe the optimal parameters of the treatment. ANOVA Analysis of results led to validate the prediction model with a determination coefficient R2=94.60% and R2=93.41% for surface roughness and micro-hardness, respectively. Furthermore, a multi-objective optimization allowed to identify a regime characterized by P=20 Kgf, i=5 passes and f=0.08 mm.rev-1, which favors minimum surface roughness and a maximum of micro-hardness. The result was validated by a composite desirability D_i=1 for both surface roughness and microhardness, respectively. Applying optimal parameters, burnishing showed its beneficial effects in fatigue resistance, especially for imposed loading in the low cycle fatigue of the material where the lifespan increased by 90%.

Keywords: AISI 52100 steel, burnishing, Taguchi, fatigue

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Authors: P. Sam Vimal Rajkumar, K. Priyanga

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Acoustics is the scientific study of sound which includes the effect of reflection, refraction, absorption, diffraction and interference. Sound can be considered as a wave phenomenon. A sound wave is a longitudinal wave where particles of the medium are temporarily displaced in a direction parallel to energy transport and then return to their original position. The vibration in a medium produces alternating waves of relatively dense and sparse particles –compression and rarefaction respectively. The resultant variation to normal ambient pressure is translated by the ear and perceived as sound. Today much importance is given to the acoustical environment. The noise sources are increased day by day and annoying level is strongly violated in different locations by traffic, sound systems, and industries. There is simple evidence showing that the high noise levels cause sleep disturbance, hearing loss, decrease in productivity, learning disability, lower scholastic performance and increase in stress related hormones and blood pressure. Therefore, achieving a pleasing and noise free environment is one of the endeavours of many a research groups. This can be obtained by using various techniques. One such technique is by using suitable materials with good sound absorbing properties. The conventionally used materials that possess sound absorbing properties are rock wool or glass wool. In this work, an attempt is made to use synthetic material in both fibrous and sheet form and use it for manufacturing of non-woven for sound absorption.

Keywords: acoustics, fibre, non-woven, noise, sound absorption properties, sound absorption coefficient

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Authors: Mamadou Sileye Niang

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The study is a contribution to the development of a feed for juvenile tilapia Oreochromis niloticus, from local raw materials in order to reduce the cost of feeding farmed tilapia in Senegal. Three feeds were formulated from local raw materials. The basic composition of the tested feeds is as follows: A1 (peanut meal, rice bran, millet bran, maize meal and no fish meal); A2 (peanut meal, rice bran, millet bran, maize meal and 10% fish meal) and A3 (peanut meal, rice bran, millet bran, maize meal and 25% fish meal). All feeds contain 31% protein. The trial compared three batches, in 2 replicates, with different diets. The initial weight of the juveniles was 0.37± 0.5g. The daily ration was distributed at 9 am and 4 pm. After 90 days of the experiment, the final mean weights were 2.45 ± 0.5g; 2.75±0.5g; and 4.67 ± 0.5g for A1, A2, and A3, respectively. A performance test, of which the objective was to compare growth parameters, was conducted. The results of the growth parameters of juveniles fed A3 were significantly higher (p < 0.05) than those fed A1 and A2. The weight growth study shows similar growth during the first month. However, from this date onwards, juveniles fed A3 show a faster growth, which is maintained throughout the experiment. On the other hand, the Protein Efficiency Coefficient and the Survival Rate showed no significant difference. The zootechnical parameters are not significantly different (p > 0.05) between the two tanks for the same feed treatment.

Keywords: nutrition, feed, fingerlings, Oreochromis, local raw materials, feed cost

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Authors: Ranjith Maniyeri, Ahamed C. Saleel

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Two-dimensional fluid flow over a stationary circular cylinder is one of the bench mark problem in the field of fluid-structure interaction in computational fluid dynamics (CFD). Motivated by this, in the present work, a two-dimensional computational model is developed using an improved version of immersed boundary method which combines the feedback forcing scheme of the virtual boundary method with Peskin’s regularized delta function approach. Lagrangian coordinates are used to represent the cylinder and Eulerian coordinates are used to describe the fluid flow. A two-dimensional Dirac delta function is used to transfer the quantities between the sold to fluid domain. Further, continuity and momentum equations governing the fluid flow are solved using fractional step based finite volume method on a staggered Cartesian grid system. The developed code is validated by comparing the values of drag coefficient obtained for different Reynolds numbers with that of other researcher’s results. Also, through numerical simulations for different Reynolds numbers flow behavior is well captured. The stability analysis of the improved version of immersed boundary method is tested for different values of feedback forcing coefficients.

Keywords: Feedback Forcing Scheme, Finite Volume Method, Immersed Boundary Method, Navier-Stokes Equations

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Authors: Stefanos Karanasios, Charkleia Koutri, Maria Moutzouri, Sofia A. Xergia, Vasiliki Sakellari, George Gioftsos

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The precise calculation of arterial occlusive pressure (AOP) is a critical step to accurately prescribe individualized pressures during blood flow restriction training (BFRT). AOP is usually measured in a supine position before training; however, previous reports suggested a significant influence in lower limb AOP across different body positions. The aim of the study was to investigate the effect of three different body positions on upper limb AOP and the reliability of the method for its standardization in clinical practice. Forty-two healthy participants (Mean age: 28.1, SD: ±7.7) underwent measurements of upper limb AOP in supine, seated, and standing positions by three blinded raters. A cuff with a manual pump and a pocket doppler ultrasound were used. A significantly higher upper limb AOP was found in seated compared with supine position (p < 0.031) and in supine compared with standing position (p < 0.031) by all raters. An excellent intraclass correlation coefficient (0.858- 0.984, p < 0.001) was found in all positions. Upper limb AOP is strongly dependent on body position changes. The appropriate measurement position should be selected to accurately calculate AOP before BFRT. The excellent inter-rater reliability and repeatability of the method suggest reliable and consistent results across repeated measurements.

Keywords: Kaatsu training, blood flow restriction training, arterial occlusion, reliability

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Authors: Kiurski S. Jelena, Kecić S. Vesna, Aksentijević M. Snežana

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Samples of tap and wastewater were collected in three offset printing facilities in Novi Sad, Serbia. Ten physicochemical parameters were analyzed within all collected samples: pH, conductivity, m - alkalinity, p - alkalinity, acidity, carbonate concentration, hydrogen carbonate concentration, active oxygen content, chloride concentration and total alkali content. All measurements were conducted using the standard analytical and instrumental methods. Comparing the obtained results for tap water and wastewater, a clear quality difference was noticeable, since all physicochemical parameters were significantly higher within wastewater samples. The study also involves the application of simple linear regression analysis on the obtained dataset. By using software package ORIGIN 5 the pH value was mutually correlated with other physicochemical parameters. Based on the obtained values of Pearson coefficient of determination a strong positive correlation between chloride concentration and pH (r = -0.943), as well as between acidity and pH (r = -0.855) was determined. In addition, statistically significant difference was obtained only between acidity and chloride concentration with pH values, since the values of parameter F (247.634 and 182.536) were higher than F_critical (5.59). In this way, results of statistical analysis highlighted the most influential parameter of water contamination in offset printing, in the form of acidity and chloride concentration. The results showed that variable dependence could be represented by the general regression model: y = a₀ + a₁x+ k, which further resulted with matching graphic regressions.

Keywords: pollution, printing industry, simple linear regression analysis, wastewater

Procedia PDF Downloads 235

Authors: Haggay Etkes

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This study provides evidence for the impact of monthly interviews conducted for the Israeli Labor Force Surveys (LFSs) on estimated flows between labor force (LF) statuses and on coefficients in fixed-effects estimations. The study uses the natural experiment of parallel interviews for the quarterly and the monthly LFSs in Israel in 2011 for demonstrating that the Labor Force Participation (LFP) rate of Jewish persons who participated in the monthly LFS increased between interviews, while in the quarterly LFS it decreased. Interestingly, the estimated impact on the LFP rate of self-reporting individuals is 2.6–3.5 percentage points while the impact on the LFP rate of individuals whose data was reported by another member of their household (a proxy), is lower and statistically insignificant. The relative increase of the LFP rate in the monthly survey is a result of a lower rate of exit from the LF and a somewhat higher rate of entry into the LF relative to these flows in the quarterly survey. These differing flows have a bearing on labor search models as the monthly survey portrays a labor market with less friction and a “steady state” LFP rate that is 5.9 percentage points higher than the quarterly survey. The study also demonstrates that monthly interviews affect a specific group (45–64 year-olds); thus the sign of coefficient of age as an explanatory variable in fixed-effects regressions on LFP is negative in the monthly survey and positive in the quarterly survey.

Keywords: measurement error, surveys, search, LFSs

Procedia PDF Downloads 270

Authors: Hernan D. Mejia, Gilberto B. Gaitan, Mauricio A. Franco

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420 steel is normally used in the manufacture of dental and surgical instrumentation, as well as parts in the chemical, pharmaceutical, and food industries, among others, where they must withstand heavy loads and often be in contact with corrosive environments, which leads to wear and deterioration of these steels in relatively short times. In the case of medical applications, the instruments made of this steel also suffer wear and corrosion during the repetitive sterilization processes due to the relatively low achievable hardness of just 50 HRC and its hardly acceptable resistance to corrosion. In order to improve the wear resistance of 420 steel, TiAlN coatings were deposited, increasing the aluminum content in the alloy by varying the power applied to the aluminum target of 900, 1100, and 1300 W. Evaluations using XRD, Micro Raman, XPS, AFM, SEM, and TEM showed a columnar growth crystal structure with an average thickness of 2 microns and consisting of the TiN and TiAlN phases, whose roughness and grain size decrease with a higher Al content. The AlN phase also appears in the sample deposited at 1300W. The hardness, determined by nanoindentation, initially increases with the aluminum content from 9.7 GPa to 17.1 GPa, but then decreases to 15.4 GPa for the sample with the highest aluminum content due to the appearance of hexagonal AlN and a decrease of harder TiN and TiAlN phases. It was observed that the wear coefficient had a contrary behavior, which took values of 2.7; 1.7 and 6.6x10⁻⁶ mm³/N.m, respectively. All the coated samples significantly improved the wear resistance of the uncoated 420 steel.

Keywords: hard coatings, magnetron sputtering, TiAlN coatings, surgical instruments, wear resistance

Procedia PDF Downloads 124