Search results for: convective mass transfer coefficient

Authors: Murat Sengoz, Mustafa Kemal Topcu

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This study aims to contribute to efforts of Turkey to increase research and development to overcome mid-income level trap by discussing regulations on patenting and licensing. Knowledge and technology transfer from universities to business world is attached great significance to increase innovation. Through literature survey, it is observed that the States accomplished to boost the economy and increase welfare by the Bayh-Dole Act enacted in 1980. Thus, this good practice is imitated by other nations to make technological developments. The Act allows universities to acquire patent right in research programs funded by government to increase technology transfer from universities whilst motivating real sector to use research pools in the universities. An act similar with Bayh-Dole could be beneficial to Turkey since efforts in Turkey are to promote research, development and innovation. Towards this end, the impact of Bayh-Dole Act on the patent system for universities in the Sates is deliberately examined, applicability in Turkey is discussed. However, it is conceded that success rate of applying Bayh-Dole Act in Turkey would be low once Turkey mainly differs from the States regarding social, economic and cultural traits.

Keywords: Bayh-Dole Act, knowledge transfer, license, patent, spin-off

Procedia PDF Downloads 280

Authors: Motahar Reza, Rajni Chahal, Neha Sharma

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This article addresses the boundary layer flow and heat transfer of Casson fluid over a nonlinearly permeable stretching surface with chemical reaction in the presence of variable magnetic field. The effect of thermal radiation is considered to control the rate of heat transfer at the surface. Using similarity transformations, the governing partial differential equations of this problem are reduced into a set of non-linear ordinary differential equations which are solved by finite difference method. It is observed that the velocity at fixed point decreases with increasing the nonlinear stretching parameter but the temperature increases with nonlinear stretching parameter.

Keywords: boundary layer flow, nonlinear stretching, Casson fluid, heat transfer, radiation

Procedia PDF Downloads 396

Authors: Sabrina Barsky, Ashley Monks

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In humans, exercise improves symptoms of various pathological states, although exercise adaptations seem to differ in response to sex. Skeletal muscle anabolism is thought to be regulated by androgen receptor (AR) through poorly specified mechanisms. Interactions of AR and exercise on muscle phenotype remain inconclusive in males, and undetermined in females. We hypothesized that sex differences in exercise adaptations are regulated by the androgenic system and the type of exercise performed. Here we examined interactions between a muscle-specific AR overexpression transgene (HSA-AR) and forced aerobic exercise paradigm on muscle and adipose exercise adaptation in male and female rats. We used dual-energy X-ray absorptiometry (DXA) to examine body composition adaptations post 9-week exercise protocol. We replicated the effects of HSA-AR on body composition, with males only having increased % lean mass and reduced % fat mass (P<0.05). Aerobic exercise improved lean body phenotype significantly, with lesser indices of total and % fat mass (P<0.01) in both sexes. Sex-specific effects of exercise included decreased total body mass (P<0.01) in males and increased lean mass % (P<0.001) in females. Surprisingly, neither AR manipulation nor exercise affected bone parameters in either sex. This varied response in total mass and lean mass according to exercise presents a sexually dimorphic response to exercise. Neither sex showed an interaction between HSA-AR and forced aerobic exercise on body composition. Future work is proposed to examine the effects of exercise type (aerobic versus resistance) and the role of gonadal androgens in sexually dimorphic exercise-mediated mitochondrial adaptations. This work implicates the development of sex-specific exercise therapies.

Keywords: androgen receptor, forced exercise, muscle physiology, sexual dimorphism

Procedia PDF Downloads 123

Authors: H. Shokouhmand, A. Ghanami

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Heat pipe is simple heat transfer device which combines the conduction and phase change phenomena to control the heat transfer without any need for external power source. At hot surface of heat pipe, the liquid phase absorbs heat and changes to vapor phase. The vapor phase flows to condenser region and with the loss of heat changes to liquid phase. Due to gravitational force the liquid phase flows to evaporator section.In HVAC systems the working fluid is chosen based on the operating temperature. The heat pipe has significant capability to reduce the humidity in HVAC systems. Each HVAC system which uses heater, humidifier or dryer is a suitable nominate for the utilization of heat pipes. Generally heat pipes have three main sections: condenser, adiabatic region and evaporator.Performance investigation and optimization of heat pipes operation in order to increase their efficiency is crucial. In present article, a parametric study is performed to improve the heat pipe performance. Therefore, the heat capacity of heat pipe with respect to geometrical and confining parameters is investigated. For the better observation of heat pipe operation in HVAC systems, a CFD simulation in Eulerian- Eulerian multiphase approach is also performed. The results show that heat pipe heat transfer capacity is higher for water as working fluid with the operating temperature of 340 K. It is also showed that the vertical orientation of heat pipe enhances it’s heat transfer capacity.

Keywords: heat pipe, HVAC system, grooved Heat pipe, heat pipe limits

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Authors: Majid Mohammadi, Mohammad Yosef Zadeh, Vahid Naderi Darshori

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The main purpose of this research is concreting of satisfaction literature for obtain index with online content in carmaker industry. The study measures customer satisfaction of online and collect from similar studies with reference to a model of online satisfaction, they are attempting to complete. Statistical communities of research are online customers' carmaker Iran Khodro has been buying the company's products in the last six months. One of the innovative measures in this study is that, customer reviews are obtained through an Internet site. Reliability of the data collected in this study, the Cronbach's alpha coefficient was approved. The coefficient of 0.828 was calculated for the questionnaire. To test the hypothesis, the Pearson correlation coefficient was used. To ensure the correctness of initial theoretical model, we used regression analyzes and structural equation weight and finally, the results obtained with little change to the basic model of research, are improved and completed. At last obtain the perceived value has most direct effect on online car customers satisfaction.

Keywords: customer satisfaction, online satisfaction, online customer, car

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Authors: Xiaohua Zhu, Lingling Ma, Yongguang Zhao

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Leaf Area Index (LAI) is a key structural characteristic of crops and plays a significant role in precision agricultural management and farmland ecosystem modeling. However, LAI retrieved from different resolution data contain a scaling bias due to the spatial heterogeneity and model non-linearity, that is, there is scale effect during multi-scale LAI estimate. In this article, a typical farmland in semi-arid regions of Chinese Inner Mongolia is taken as the study area, based on the combination of PROSPECT model and SAIL model, a multiple dimensional Look-Up-Table (LUT) is generated for multiple crops LAI estimation from unmanned aerial vehicle (UAV) hyperspectral data. Based on Taylor expansion method and computational geometry model, a scale transfer model considering both difference between inter- and intra-class is constructed for scale effect analysis of LAI inversion over inhomogeneous surface. The results indicate that, (1) the LUT method based on classification and parameter sensitive analysis is useful for LAI retrieval of corn, potato, sunflower and melon on the typical farmland, with correlation coefficient R2 of 0.82 and root mean square error RMSE of 0.43m2/m-2. (2) The scale effect of LAI is becoming obvious with the decrease of image resolution, and maximum scale bias is more than 45%. (3) The scale effect of inter-classes is higher than that of intra-class, which can be corrected efficiently by the scale transfer model established based Taylor expansion and Computational geometry. After corrected, the maximum scale bias can be reduced to 1.2%.

Keywords: leaf area index (LAI), scale effect, UAV-based hyperspectral data, look-up-table (LUT), remote sensing

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Authors: Hikari Ryu, Yuki Fukuda, Kento Oishi, Chiharu Igarashi, Shogo Kiryu

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Recently, wireless power transfer has been developed in various fields. Magnetic coupling is popular for feeding power at a relatively short distance and at a lower frequency. Electro-magnetic wave coupling at a high frequency is used for long-distance power transfer. The wireless power transfer has attracted attention in e-textile fields. Rigid batteries are required for many body-worn electric systems at the present time. The technology enables such batteries to be removed from the systems. Flexible coils have been studied for such applications. Coils with a high Q factor are required in the magnetic-coupling power transfer. Antennas with low return loss are needed for the electro-magnetic coupling. Litz wire is so flexible to fabricate coils and antennas sewn on fabric and has low resistivity. In this study, the electric characteristics of some coils and antennas fabricated with the Litz wire by using two sewing techniques are investigated. As examples, a coil and an antenna are described. Both were fabricated with 330/0.04 mm Litz wire. The coil was a planar coil with a square shape. The outer side was 150 mm, the number of turns was 15, and the pitch interval between each turn was 5 mm. The Litz wire of the coil was overstitched with a sewing machine. The coil was fabricated as a receiver coil for a magnetic coupled wireless power transfer. The Q factor was 200 at a frequency of 800 kHz. A wireless power system was constructed by using the coil. A power oscillator was used in the system. The resonant frequency of the circuit was set to 123 kHz, where the switching loss of power FETs was small. The power efficiencies were 0.44 – 0.99, depending on the distance between the transmitter and receiver coils. As an example of an antenna with a sewing technique, a fractal pattern antenna was stitched on a 500 mm x 500 mm fabric by using a needle punch method. The pattern was the 2nd-oder Vicsec fractal. The return loss of the antenna was -28 dB at a frequency of 144 MHz.

Keywords: e-textile, flexible coils and antennas, Litz wire, wireless power transfer

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Authors: Ahmed Al-Saadi, Ali Hassanpour, Tariq Mahmud

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The main objective of this study is to investigate ways to reduce the aerodynamic drag coefficient and to increase the stability of the full-size Sport Utility Vehicle using three-dimensional Computational Fluid Dynamics (CFD) simulation. The baseline model in the simulation was the Land Rover Discovery 4. Many aerodynamic devices and external design modifications were used in this study. These reduction aerodynamic techniques were tested individually or in combination to get the best design. All new models have the same capacity and comfort of the baseline model. Uniform freestream velocity of the air at inlet ranging from 28 m/s to 40 m/s was used. ANSYS Fluent software (version 16.0) was used to simulate all models. The drag coefficient obtained from the ANSYS Fluent for the baseline model was validated with experimental data. It is found that the use of modern aerodynamic add-on devices and modifications has a significant effect in reducing the aerodynamic drag coefficient.

Keywords: aerodynamics, RANS, sport utility vehicle, turbulent flow

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Authors: Avijit Datta

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We have presented a phase control scheme in population transfer using chirped laser fields. A chirped pulse can do population transfer from one level to another level via adiabatic rapid passage accessible by one photon dipole transition. We propose to use a pair of phase-locked chirped pulses of the same frequency w(t) instead of a singly chirped-pulse frequency w(t). Simultaneous action of phase controlled interference in addition to rapid adiabatic passages due to chirped pulses lead to phase control over this population transfer dynamics. We have demonstrated the proposed phase control scheme over the population distribution from the initial level X(v=0,j=0) to C(v=2,j=1) level of hydrogen molecule using a pair of phase-locked and similarly chirped laser pulses. We have extended this two-level system to three-level 1+1 ladder system of hydrogen molecule from X level to final J(v=2,j=2) level via C intermediate level using two pairs of laser pulses having frequencies w(t) and w'(t) respectively and obtained laudable control over the population distribution among three levels. We also have presented some results of interference effects of w₁(t) and its third harmonics w₃(t).

Keywords: phase control, population transfer, chirped laser pulses, rapid adiabatic passage, laser-molecule interaction

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Authors: Orkide Donma, Mustafa M. Donma

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Obesity is associated with increased fat mass as well as fat percentage. Minerals are the elements, which are of vital importance. In this study, the relationships between body as well as bone mineral profile and the percentage as well as mass values of fat, fat-free portion, protein, skeletal muscle were evaluated in adult men with normal body mass index (N-BMI), and those classified according to different stages of obesity. A total of 103 adult men classified into five groups participated in this study. Ages were within 19-79 years range. Groups were N-BMI (Group 1), overweight (OW) (Group 2), first level of obesity (FLO) (Group 3), second level of obesity (SLO) (Group 4) and third level of obesity (TLO) (Group 5). Anthropometric measurements were performed. BMI values were calculated. Obesity degree, total body fat mass, fat percentage, basal metabolic rate (BMR), visceral adiposity, body mineral mass, body mineral percentage, bone mineral mass, bone mineral percentage, fat-free mass, fat-free percentage, protein mass, protein percentage, skeletal muscle mass and skeletal muscle percentage were determined by TANITA body composition monitor using bioelectrical impedance analysis technology. Statistical package (SPSS) for Windows Version 16.0 was used for statistical evaluations. The values below 0.05 were accepted as statistically significant. All the groups were matched based upon age (p > 0.05). BMI values were calculated as 22.6 ± 1.7 kg/m², 27.1 ± 1.4 kg/m², 32.0 ± 1.2 kg/m², 37.2 ± 1.8 kg/m², and 47.1 ± 6.1 kg/m² for groups 1, 2, 3, 4, and 5, respectively. Visceral adiposity and BMR values were also within an increasing trend. Percentage values of mineral, protein, fat-free portion and skeletal muscle masses were decreasing going from normal to TLO. Upon evaluation of the percentages of protein, fat-free portion and skeletal muscle, statistically significant differences were noted between NW and OW as well as OW and FLO (p < 0.05). However, such differences were not observed for body and bone mineral percentages. Correlation existed between visceral adiposity and BMI was stronger than that detected between visceral adiposity and obesity degree. Correlation between visceral adiposity and BMR was significant at the 0.05 level. Visceral adiposity was not correlated with body mineral mass but correlated with bone mineral mass whereas significant negative correlations were observed with percentages of these parameters (p < 0.001). BMR was not correlated with body mineral percentage whereas a negative correlation was found between BMR and bone mineral percentage (p < 0.01). It is interesting to note that mineral percentages of both body as well as bone are highly affected by the visceral adiposity. Bone mineral percentage was also associated with BMR. From these findings, it is plausible to state that minerals are highly associated with the critical stages of obesity as prominent parameters.

Keywords: bone, men, minerals, obesity

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Authors: Jingjing Huang, Nengwei Li, Guanghua Wei, Jiabin You, Chao Wang, Junliang Zhang

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In this work, molecular dynamics (MD) simulation is applied to analyze the mass transport process in the cathode of proton exchange membrane fuel cell (PEMFC), of which all types of molecules situated in the cathode is considered. a reasonable and effective MD simulation process is provided, and models were built and compared using both Materials Studio and LAMMPS. The mass transport is one of the key issues in the study of proton exchange membrane fuel cells (PEMFCs). In this report, molecular dynamics (MD) simulation is applied to analyze the influence of Nafion ionomer distribution and Pt nano-particle size on mass transport process in the cathode. It is indicated by the diffusion coefficients calculation that a larger quantity of Nafion, as well as a higher equivalent weight (EW) value, will hinder the transport of oxygen. In addition, medium-sized Pt nano-particles (1.5~2nm) are more advantageous in terms of proton transport compared with other particle sizes (0.94~2.55nm) when the center-to-center distance between two Pt nano-particles is around 5 nm. Then mass transport channels are found to be formed between the hydrophobic backbone and the hydrophilic side chains of Nafion ionomer according to the radial distribution function (RDF) curves. And the morphology of these channels affected by the Pt size is believed to influence the transport of hydronium ions and, consequently the performance of PEMFC.

Keywords: cathode catalytic layer, mass transport, molecular dynamics, proton exchange membrane fuel cell

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Authors: Junting Xiang, Jörg Uwe Schlüter, Fei Duan

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The miniaturization of gas turbines promises many advantages. Miniature gas turbines can be used for local power generation or the propulsion of small aircraft, such as UAV and MAV. However, experience shows that the miniaturization of conventional gas turbines, which are optimized at their current large size, leads to a substantial loss of efficiency and performance at smaller scales. This may be due to a number of factors, such as the Reynolds-number effect, the increased heat transfer, and manufacturing tolerances. In the present work, we focus on computational investigations of the Reynolds number effect and the wall heat transfer on the performance of axial compressor during its size change. The NASA stage 35 compressors are selected as the configuration in this study and Computational Fluid Dynamics (CFD) is used to carry out the miniaturization process and simulations. We perform parameter studies on the effect of Reynolds number and wall thermal conditions. Our results indicate a decrease of efficiency, if the compressor is miniaturized based on its original geometry due to the increase of viscous effects. The increased heat transfer through wall has only a small effect and will actually benefit compressor performance based on our study.

Keywords: axial compressor, CFD, heat transfer, miniature gas turbines, Reynolds number

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Authors: Bae Doobyong, Yoo Jaejun, Park Ilgyu, Choi Seowon, Oh Chang Kook

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Variation of slip coefficient in slip-critical connections of curved plates. This paper presents the results of analytical investigations of slip coefficients in slip-critical bolted connections of curved plates. It may depend on the contact stress distribution at interface and the flexibility of spliced plate. Non-linear FEM analyses have been made to simulate the behavior of bolted connections of curved plates with various radiuses of curvature and thicknesses.

Keywords: slip coefficient, curved plates, slip-critical bolted connection, radius of curvature

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Authors: Danuta Barnat-Hunek

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The studies are devoted to assessing the effectiveness of hydrophobic and air entraining admixtures based on organ silicon compounds. Mortars with lightweight aggregate–perlite were the subjects of the investigation. The following laboratory tests were performed: density, open porosity, total porosity, absorptivity, capability to diffuse water vapour, compressive strength, flexural strength, frost resistance, sodium sulphate corrosion resistance and the thermal conductivity coefficient. The composition of the two mixtures of mortars was prepared: mortars without a hydrophobic admixture and mortars with cementitious waterproofing material. Surface hydrophobisation was produced on the mortars without a hydrophobic admixture using a methyl silicone resin, a water-based emulsion of methyl silicone resin in potassium hydroxide and alkyl-alkoxy-silane in organic solvents. The results of the effectiveness of hydrophobisation of mortars are the following: The highest absorption after 14 days of testing was shown by mortar without an agent (57.5%), while the lowest absorption was demonstrated by the mortar with methyl silicone resin (52.7%). After 14 days in water the hydrophobisation treatment of the samples proved to be ineffective. The hydrophobised mortars are characterized by an insignificant mass change due to freezing and thawing processes in the case of the methyl silicone resin – 1%, samples without hydrophobisation –5%. This agent efficiently protected the mortars against frost corrosion. The standard samples showed very good resistance to the pressure of sodium sulphate crystallization. Organosilicon compounds have a negative influence on the chemical resistance (weight loss about 7%). The mass loss of non-hydrophobic mortar was 2 times lower than mortar with the hydrophobic admixture. Hydrophobic and aeration admixtures significantly affect the thermal conductivity and the difference is mainly due to the difference in porosity of the compared materials. Hydrophobisation of the mortar mass slightly decreased the porosity of the mortar, and thus in an increase of 20% of its compressive strength. The admixture adversely affected the ability of the hydrophobic mortar – it achieved the opposite effect. As a result of hydrophobising the mass, the mortar samples decreased in density and had improved wettability. Poor protection of the mortar surface is probably due to the short time of saturating the sample in the preparation. The mortars were characterized by high porosity (65%) and water absorption (57.5%), so in order to achieve better efficiency, extending the time of hydrophobisation would be advisable. The highest efficiency was obtained for the surface hydrophobised with the methyl silicone resin.

Keywords: hydrophobisation, mortars, salt crystallization, frost resistance

Procedia PDF Downloads 207

Authors: A. S. Fetisova, M. N. Erofeeva, G. S. Alekseeva, K. A. Volobueva, M. D. Kim, S. V. Naidenko

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Weaning is characterized by the transition from milk to solid food. In some species, such changes in diet are fast and gradual in others. The reasons for the weaning start are understandable. Changes in milk composition and decrease in maternity behavior push cubs to search for additional sources of nutrients. In nature, females have many opportunities to wean offspring in case of a lack of resources. In contrast, in controlled conditions the possibility of delayed weaning exists. The delay of weaning can lead to overspending of maternal resources. In addition, the main causes of weaning end are not so obvious. Near the weaning end behavior of offspring depends on many factors: intensity of maternal behavior, reduction of milk abundance, brood size, physiological status, and body mass. During the pre-weaning period dynamic of body mass is strongly connected with milk intake. Based on that fact could body mass be one of the signals for end of milk feeding? It is known that some animals usually wean their offspring when juveniles achieved body mass in some proportion to the adult weight. In turn, we put forward the hypothesis that decrease in growth rates causes the delay of weaning in Eurasian lynxes (Lynx lynx). To explore the hypothesis, we compared the dynamic of body mass with duration of milk suckling. Firstly, to get information about duration of suckling we visually observed 8 lynx broods from 30 to 120 days postpartum. During each 4-hour observation we registered the start and the end of suckling acts and then calculate the total duration of this behavior. To get the dynamic of body mass kittens were weighed once a week. Duration of suckling varied from 3076,19 ± 1408,60 to 422,54 ± 285,38 seconds when body mass gain changed from 247,35 ± 26,49 to 289,41 ± 122,35 grams. Results of Kendall Tau correlation test (N= 96; p< 0,05) showed a negative correlation (τ= -0,36) between duration of suckling and body mass of lynx kittens. In general duration of suckling increases in response to decrease in body mass gain with slight delay. In early weaning from 30 to 58 days duration of suckling decreases gradually as does the body mass gain. During the weaning period the negative correlation between suckling time and body mass becomes tighter. Although throughout the weaning consumption of solid food begins to prevail over the milk intake, the correlation persists until the end of weaning (90-105 days) and after it. In that way weaning in Eurasian lynxes is not a part of ontogenesis controlled only by maternal behavior. It seems to be a flexible process influenced by various factors including changes in growth rates. It is necessary to continue investigations to determine the critical value of body mass which marks the safe moment to stop milk feeding. Understanding such details of ontogenesis is very important to organize procedures aimed at the reproduction of mammals ex situ and the conservation of endangered species.

Keywords: body mass, lynx, milk feeding, weaning

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Authors: Hisham Mousa Mohammed Ahmed, Ahmed Wali Mohamed Salad, Yousif Hamed Dldom Gomaa

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A drip or Trickle irrigation system is designed to apply a precise amount of water near the plant with a certain degree of uniformity. This study was conducted at the Experimental Farm of the Faculty of Agricultural Sciences, University of Gezira, in March 2018. The study aimed to design and evaluate the hydraulic performance of three drip emitter types using: average discharge (Qavg), discharge variation (Qvar %), coefficient of uniformity (CU %), coefficient of manufacturer variation (CV %), distribution uniformity (DU %), statistical uniformity (Us %), clogging (%) wetted diameter (cm) and wetted depth (cm). The emitter types used are regular gauges (RG), high compensating pressure (HCP) and low compensating pressure (LCP). The treatments were laid out in a randomized complete block design (RCBD) with four replications. Results showed that there were significant differences (P≤0.05) in all tested parameters except clogging, wetted diameter and wetted depth. Discharge variation (Qvar %) values were 12.71, 15.57 and 19.17 for RG, LCP, and HCP, respectively. The variation is quite good and within the acceptable range. Results of coefficient of manufacture variation (CV %) were 10.9, 27.8 and 52.7 for RG, LCP and HCP, respectively. It is considered within the unacceptable range except for RG type, which is excellent. Statistical uniformity (Us %) values were 89.1, 72.2 and 45.7 for RG, LCP and HCP, respectively. It is considered good, acceptable and unacceptable, respectively. Results of the coefficient of uniformity (CU %) were 91.3, 77.7 and 56.7 for RG, LCP and HCP, respectively. It is considered excellent, fair and unacceptable, respectively. Distribution uniformity (DU %) was 90.2, 67.9 and 36.5 for RG, LCP and HCP, respectively. It is considered excellent, poor and poor, respectively. The study recommended regular gauges (RG) type emitters under the heavy clay soil conditions of the Gezira State, Sudan.

Keywords: drip irrigation, uniformity, clogging, coefficient, performance

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Authors: Hongmei Gu, Shaobo Liang, Richard Bergman

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With current worldwide trend in designs to have net-zero emission buildings to mitigate climate change, widespread use of mass timber products, such as Cross Laminated Timber (CLT), or Nail Laminated Timber (NLT) or Dowel Laminated Timber (DLT) in buildings have been proposed as one approach in reducing Greenhouse Gas (GHG) emissions. Consequentially, mass timber building designs are being adopted more and more by architectures in North America, especially for mid- to high-rise buildings where concrete and steel buildings are currently prevalent, but traditional light-frame wood buildings are not. Wood buildings and their associated wood products have tended to have lower environmental impacts than competing energy-intensive materials. It is common practice to conduct life cycle assessments (LCAs) and life cycle cost analyses on buildings with traditional structural materials like concrete and steel in the building design process. Mass timber buildings with lower environmental impacts, especially GHG emissions, can contribute to the Net Zero-emission goal for the world-building sector. However, the economic impacts from CLT mass timber buildings still vary from the life-cycle cost perspective and environmental trade-offs associated with GHG emissions. This paper quantified the Total Life Cycle Cost and cradle-to-grave GHG emissions of a pre-designed CLT mass timber building and compared it to a functionally-equivalent concrete building. The Total life cycle Eco-cost-efficiency is defined in this study and calculated to discuss the trade-offs for the net-zero emission buildings in a holistic view for both environmental and economic impacts. Mass timber used in buildings for the United States is targeted to the materials from the nation’s sustainable managed forest in order to benefit both national and global environments and economies.

Keywords: GHG, economic impact, eco-cost-efficiency, total life-cycle costs

Procedia PDF Downloads 132

Authors: K. Abuzayan, H. Alabed, J. Ezarrugh, M. Agila

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Static and dynamic balance are essential in daily and sports life. Many factors have been identified as influencing static balance control. Therefore, the aim of this study was to apply the (XCoM) method and other relevant variables (CoP, CoM, Fh, KE, P, Q, and, AI) to investigate sport related activities such as hopping and jumping. Many studies have represented the CoP data without mentioning its accuracy, so several experiments were done to establish the agreement between the CoP and the projected CoM in a static condition. Five male healthy (Mean ± SD:- age 24.6 years ±4.5, height 177 cm ± 6.3, body mass 72.8 kg ± 6.6) participated in this study. Results found that The implementation of the XCoM method was found to be practical for evaluating both static and dynamic balance. The general findings were that the CoP, the CoM, the XCoM, Fh, and Q were more informative than the other variables (e.g. KE, P, and AI) during static and dynamic balance. The XCoM method was found to be applicable to dynamic balance as well as static balance.

Keywords: centre of mass, static balance, dynamic balance, extrapolated centre of mass

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Authors: Sergei P. Efimov

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The anomalous magnetic moment of the electron is calculated by introducing the effective mass of the virtual part of the electron structure. In this case, the anomalous moment is inversely proportional to the effective mass Meff, which is shown to be a linear combination of the neutron, proton, and electrostatic electron field masses. The spin of a rotating structure is assumed to be equal to 3/2, while the spin of a 'bare' electron is equal to unity, the resultant spin being 1/2. A simple analysis gives the coefficients for a linear combination of proton and electron masses, the approximation precision giving here nine significant digits after the decimal point. The summand proportional to α² adds four more digits. Thus, the conception of the effective mass Meff leads to the formula for the total magnetic moment of the electron, which is accurate to fourteen digits. Association with the virtual beta-decay reaction and possible reasons for simplicity of the derived formula are discussed.

Keywords: anomalous magnetic moment of electron, comparison with quantum electrodynamics. effective mass, fifteen significant figures, proton and neutron masses

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Authors: Radouane Elbahjaoui, Hamid El Qarnia

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The present work aims to investigate numerically the thermal and flow characteristics of a rectangular latent heat storage unit (LHSU) during the melting process of a phase change material (PCM). The LHSU consists of a number of vertical and identical plates of PCM separated by rectangular channels. The melting process is initiated when the LHSU is heated by a heat transfer fluid (HTF: water) flowing in channels in a downward or upward direction. The proposed study is motivated by the need to optimize the thermal performance of the LHSU by accelerating the charging process. A mathematical model is developed and a fixed-grid enthalpy formulation is adopted for modeling the melting process coupling with convection-conduction heat transfer. The finite volume method was used for discretization. The obtained numerical results are compared with experimental, analytical and numerical ones found in the literature and reasonable agreement is obtained. Thereafter, the numerical investigations were carried out to highlight the effects of the HTF flow direction and the aspect ratio of the PCM slabs on the heat transfer characteristics and thermal performance enhancement of the LHSU.

Keywords: PCM, TES, LHSU, melting

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Authors: Zainab Mohammed Shukur, Najlaa Ali Alboshmina, Ali Safa Alsaegh

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The project was investigated tribological behavior of polyether ether ketone (PEEK1000) against PEEK1000 rolling sliding (non-conformal) configuration with slip ratio 83.3%, were tested applications using a TE77 wear mechanisms and friction coefficient test rig. Under marginal lubrication conditions and the absence of film thick conditions, load 100 N was used to simulate the torque in gears 7 N.m. The friction coefficient and wear mechanisms of PEEK were studied under reciprocating roll/slide conditions with water, ethylene glycol, silicone, and base oil. Tribological tests were conducted on a TE77 high-frequency tribometer, with a disc-on-plate slide/roll (the energy pulse criterion) configuration. An Alicona G5 optical 3D micro-coordinate measurement microscope was used to investigate the surface topography and wear mechanisms. The surface roughness had been a significant effect on the friction coefficient for the PEEK/PEEK the rolling sliding contact test ethylene glycol and on the wear mechanisms. When silicone, ethylene glycol, and oil were used as a lubricant, the steady state of friction coefficient was reached faster than the other lubricant. Results describe the effect of the film thick with slip ratio of 83.3% on the tribological performance.

Keywords: polymer, rolling- sliding, energy pulse, gear contact

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Authors: M. Yousaf, S. Usman

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The present study focused on the investigation of the effects of roughness elements on heat transfer during natural convection in a rectangular cavity using a numerical technique. Roughness elements were introduced on the bottom hot wall with a normalized amplitude (A*/H) of 0.1. Thermal and hydrodynamic behavior was studied using a computational method based on Lattice Boltzmann method (LBM). Numerical studies were performed for a laminar natural convection in the range of Rayleigh number (Ra) from 103 to 106 for a rectangular cavity of aspect ratio (L/H) 2 with a fluid of Prandtl number (Pr) 1.0. The presence of the sinusoidal roughness elements caused a minimum to the maximum decrease in the heat transfer as 7% to 17% respectively compared to the smooth enclosure. The results are presented for mean Nusselt number (Nu), isotherms, and streamlines.

Keywords: natural convection, Rayleigh number, surface roughness, Nusselt number, Lattice Boltzmann method

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Authors: Ramli Nazir, Hossein Moayedi

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Soil confinement systems serve as effective solutions to any erosion control project. Various confinements systems, namely triangular, circular and rectangular with the size of 50, 100, and 150 mm, and with a depth of 10 mm, were embedded in soil samples at slope angle of 60°. The observed soil mass losses for the confined soil systems were much smaller than those from unconfined system. As a result, the size of confinement and rainfall intensity have a direct effect on the soil mass loss. The triangular and rectangular confinement systems showed the lowest and highest soil loss masses, respectively. The slopes also failed much faster in the unconfined system than in the confined slope.

Keywords: erosion control, soil confinement, soil erosion, slope stability

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Authors: Simran Baweja, Bhavika Kalal, Surajit Maity

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Photoinduced tautomerization reactions have been the centre of attention among the scientific community over the past several decades because of their significance in various biological systems. 7-azaindole (7AI) is considered a model system for DNA base pairing and to understand the role of such tautomerization reactions in mutations. To the best of our knowledge, extensive studies have been carried out on 7-azaindole and its solvent clusters exhibiting proton/ hydrogen transfer in both solution as well as gas phases. Derivatives of the above molecule, like 2,7- and 2,6-diazaindoles are proposed to have even better photophysical properties due to the presence of -aza group on the 2nd position. However, there are studies in the solution phase that suggest the relevance of these molecules, but there are no experimental studies reported in the gas phase yet. In our current investigation, we present the first gas phase spectroscopic data of 2,7-diazaindole (2,7-DAI) and its solvent cluster (2,7-DAI-H2O). In this, we have employed state-of-the-art laser spectroscopic methods such as fluorescence excitation (LIF), dispersed fluorescence (DF), resonant two-photon ionization-time of flight mass spectrometry (2C-R2PI), photoionization efficiency spectroscopy (PIE), IR-UV double resonance spectroscopy, i.e., fluorescence-dip infrared spectroscopy (FDIR) and resonant ion-dip infrared spectroscopy (IDIR) to understand the electronic structure of the molecule. The origin band corresponding to the S1 ← S0 transition of the bare 2,7-DAI is found to be positioned at 33910 cm-1, whereas the origin band corresponding to S1 ← S0 transition of the 2,7-DAI-H2O is positioned at 33074 cm-1. The red-shifted transition in the case of solvent cluster suggests the enhanced feasibility of excited state hydrogen/ proton transfer. The ionization potential for the 2,7-DAI molecule is found to be 8.92 eV which is significantly higher than the previously reported 7AI (8.11 eV) molecule, making it a comparatively complex molecule to study. The ionization potential is reduced by 0.14 eV in the case of 2,7-DAI-H2O (8.78 eV) cluster compared to that of 2,7-DAI. Moreover, on comparison with the available literature values of 7AI, we found the origin band of 2,7-DAI and 2,7-DAI-H2O to be red-shifted by -729 and -280 cm-1 respectively. The ground and excited state N-H stretching frequencies of the 27DAI molecule were determined using fluorescence-dip infrared spectra (FDIR) and resonant ion dip infrared spectroscopy (IDIR), obtained at 3523 and 3467 cm-1, respectively. The lower value of vNH in the electronically excited state of 27DAI implies the higher acidity of the group compared to the ground state. Moreover, we have done extensive computational analysis, which suggests that the energy barrier in the excited state reduces significantly as we increase the number of catalytic solvent molecules (S= H2O, NH3) as well as the polarity of solvent molecules. We found that the ammonia molecule is a better candidate for hydrogen transfer compared to water because of its higher gas-phase basicity. Further studies are underway to understand the excited state dynamics and photochemistry of such N-rich chromophores.

Keywords: excited state hydrogen transfer, supersonic expansion, gas phase spectroscopy, IR-UV double resonance spectroscopy, laser induced fluorescence, photoionization efficiency spectroscopy

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Authors: Wael Al-Kouz

Abstract:

Numerical simulations to study heat transfer and flow characteristics of mixed convection for rarefied gas in a square enclosure are utilized. Effect of the geometry in terms of the location of the inlet and exit openings are investigated. Moreover, effect of Knudsen number on the flow and heat transfer characteristics is illustrated and discussed. Results of the simulations show that there is a configuration that yields better heat transfer. This configuration is found to be the geometry in which the inlet opening is in the top left corner and the exit opening is at the bottom right corner. In addition, it is found that by increasing Knudsen number, Nusselt number will decrease.

Keywords: Knudsen number, mixed convection, rarefied gas, square enclosure

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Authors: S. S. Nafee, A. M. Al-Ramady, S. A. Shaheen

Abstract:

Evaluated nuclear decay data for the 217Po nuclide ispresented in the present work. These data include recommended values for the half-life T1/2, α-, β--, and γ-ray emission energies and probabilities. Decay data from 221Rn α and 217Bi β—decays are presented. Q(α) has been updated based on the recent published work of the Atomic Mass Evaluation AME2012. In addition, the logft values were calculated using the Logft program from the ENSDF evaluation package. Moreover, the total internal conversion electrons has been calculated using Bricc program. Meanwhile, recommendation values or the multi-polarities have been assigned based on recently measurement yield a better intensity balance at the 254 keV and 264 keV gamma transitions.

Keywords: nuclear decay data evaluation, mass evaluation, total converison coefficients, atomic mass evaluation

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Authors: Shokouh Momeni, Mohammad Reza Salamat, Ali Asghar Rastegari

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Background: Osteoporosis is the most prevalent metabolic bone disease in postmenopausal women associated with reduced bone mass and increased bone fracture. Measuring bone density in the lumbar spine and hip is a reliable measure of bone mass and can therefore specify the risk of fracture. Dual-energy X-ray absorptiometry(DXA) is an accurate non-invasive system measuring the bone density, with low margin of error and no complications. The present study aimed to investigate the relationship between biochemical parameters with bone density in postmenopausal women. Materials and methods: This cross-sectional study was conducted on 87 postmenopausal women referred to osteoporosis centers in Isfahan. Bone density was measured in the spine and hip area using DXA system. Serum levels of calcium, phosphorus, alkaline phosphatase and magnesium were measured by autoanalyzer and serum levels of vitamin D were measured by high-performance liquid chromatography(HPLC). Results: The mean parameters of calcium, phosphorus, alkaline phosphatase, vitamin D and magnesium did not show a significant difference between the two groups(P-value>0.05). In the control group, the relationship between alkaline phosphatase and BMC and BA in the spine was significant with a correlation coefficient of -0.402 and 0.258, respectively(P-value<0.05) and BMD and T-score in the femoral neck area showed a direct and significant relationship with phosphorus(Correlation=0.368; P-value=0.038). There was a significant relationship between the Z-score with calcium(Correlation=0.358; P-value=0.044). Conclusion: There was no significant relationship between the values ​​of calcium, phosphorus, alkaline phosphatase, vitamin D and magnesium parameters and bone density (spine and hip) in postmenopaus

Keywords: osteoporosis, menopause, bone mineral density, vitamin d, calcium, magnesium, alkaline phosphatase, phosphorus

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Authors: Akanksha Singh, Mahesh Kumar, Shailesh N. Sharma

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Semiconductor quantum dots (QDs) such as CdSe, CdS, InP, etc. have gained significant interest in the recent years due to its application in various fields such as LEDs, solar cells, lasers, biological markers, etc. The interesting feature of the QDs is their tunable band gap. The size of the QDs can be easily varied by varying the synthesis parameters which change the band gap. One of the limitations with II-VI semiconductor QDs is their biological application. The use of cadmium makes them unsuitable for biological applications. III-V QD such as InP overcomes this problem as they are structurally robust because of the covalent bonds which do not allow the ions to leak. Also, InP QDs has large Bohr radii which increase the window for the quantum confinement effect. The synthesis of InP QDs is difficult and time consuming. Authors have synthesized InP using a novel, quick synthesis method which utilizes trioctylphosphine as a source of phosphorus. In this work, authors have made InP composites with P3HT(Poly(3-hexylthiophene-2,5-diyl))polymer(organic-inorganic hybrid material) and gold nanoparticles(metal-semiconductor composites). InP-P3HT shows FRET phenomenon whereas InP-Au shows charge transfer mechanism. The synthesized InP QDs has an absorption band at 397 nm and PL peak position at 491 nm. The band gap of the InP QDs is 2.46 eV as compared to the bulk band gap of InP i.e. 1.35 eV. The average size of the QDs is around 3-4 nm. In order to protect the InP core, a shell of wide band gap material i.e. ZnS is coated on the top of InP core. InP-P3HT composites were made in order to study the charge transfer/energy transfer phenomenon between them. On adding aliquots of P3HT to InP QDs solution, the P3HT PL increases which can be attributed to the dominance of Förster energy transfer between InP QDs (donor) P3HT polymer (acceptor). There is a significant spectral overlap between the PL spectra of InP QDs and absorbance spectra of P3HT. But in the case of InP-Au nanocomposites, significant charge transfer was seen from InP QDs to Au NPs. When aliquots of Au NPs were added to InP QDs, a decrease in the PL of the InP QDs was observed. This is due to the charge transfer from the InP QDs to the Au NPs. In the case of metal semiconductor composites, the enhancement and quenching of QDs depend on the size of the QD and the distance between the QD and the metal NP. These two composites have different phenomenon between donor and acceptor and hence can be utilized for two different applications. The InP-P3HT composite can be utilized for LED devices due to enhancement in the PL emission (FRET). The InP-Au can be utilized efficiently for photovoltaic application owing to the successful charge transfer between InP-Au NPs.

Keywords: charge transfer, FRET, gold nanoparticles, InP quantum dots

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Authors: Ich Long Ngo, Dinh Tai Dang, Ngoc Tu Nguyen, Minh Duc Nguyen

Abstract:

This paper describes an investigation on designing and enhancing the performance of H-Darrieus wind turbine (HDWT) of 10kW at the medium wind speed. The aerodynamic characteristics of this turbine were investigated by both theoretical and numerical approaches. The optimal design procedure was first proposed to enhance the power coefficient under various effects, such as airfoil type, number of blades, solidity, aspect ratio, and tip speed ratio. As a result, the overall design of the 10kW HDWT was well achieved, and the power characteristic of this turbine was found by numerical approach. Additionally, the maximum power coefficient predicted is up to 0.41 at the tip speed ratio of 3.7 and wind speed of 8 m/s. Particularly, a generalized correlation of power coefficient with tip speed ratio and wind speed is first proposed. These results obtained are very useful for enhancing the performance of the HDWTs placed in a country with high wind power potential like Vietnam.

Keywords: computational fluid dynamics, double multiple stream tube, h-darrieus wind turbine, renewable energy

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Authors: Muslim Khan, Kenneth B. Jensen, Kevin A. Francesconi

Abstract:

Trace amounts (ca 1 µg/L, 13 nM) of arsenic are present in sea water mostly as the oxyanion arsenate. In contrast, arsenic is present in marine biota (animals and algae) at very high levels (up to100,000 µg/kg) a significant portion of which is present as lipid-soluble compounds collectively termed arsenolipids. The complex nature of sea water presents an analytical challenge to detect trace compounds and monitor their environmental path. We developed a simple method using liquid-liquid extraction combined with HPLC-High Resolution Mass Spectrometer capable of detecting trace of arsenolipids (99 % of the sample matrix while recovering > 80 % of the six target arsenolipids with limit of detection of 0.003 µg/L.)

Keywords: arsenolipids, sea water, HPLC-high resolution mass spectrometry

Procedia PDF Downloads 364