Search results for: major shear

Authors: Ravinesh C. Deo

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This article investigates through experiments the flow characteristics of plane jets from sharp-edged orifice-plate, beveled-edge and radially contoured nozzle. The first two configurations exhibit saddle-backed velocity profiles while the third shows a top-hat. A vena contracta is found for the jet emanating from orifice at x/h = 3 while the contoured case displays a potential core extending to the range x/h = 5. A spurt in jet pressure on the centerline supports vena contracta for the orifice-jet. Momentum thicknesses and integral length scales elongate linearly with x although the growth of the shear-layer and large-scale eddies for the orifice are greater than the contoured case. The near-field spectrum exhibits higher frequency of the primary eddies that concur with enhanced turbulence intensity. Importantly, highly “turbulent” state of the orifice-jet prevails in the far-field where the spectra confirm more energetic secondary eddies associated with greater flapping amplitude of the orifice-jet.

Keywords: orifice, beveled-edge-orifice, radially contoured nozzle, plane jets

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Authors: Baha Vural Kök, Mehmet Yilmaz, Mustafa Akpolat, Cihat Sav

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Various types of additives are used frequently in order to improve the rheological and mechanical properties of bituminous mixtures. Small devices instead of full scale machines are used for bitumen modification in the laboratory. These laboratory scale devices vary in terms of their properties such as mixing rate, mixing blade and the amount of binder. In this study, the effect of mixing rate and time during the bitumen modification processes on conventional and rheological properties of pure and crumb rubber modified binder were investigated. Penetration, softening point, rotational viscosity (RV) and dynamic shear rheometer (DSR) tests were applied to pure and CR modified bitumen. It was concluded that the penetration and softening point test did not show the efficiency of CR obtained by different mixing conditions. Besides, oxidation that occurred during the preparation processes plays a great part in the improvement effects of the modified binder.

Keywords: bitumen, crumb rubber, modification, rheological properties

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Authors: Aleksander Nawrat, Karol Jędrasiak, Artur Ryt, Dawid Sobel

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The goal of the article is to present a novel Multimedia Firearms Training System. The system was developed in order to compensate for major problems of existing shooting training systems. The designed and implemented solution can be characterized by five major advantages: algorithm for automatic geometric calibration, algorithm of photometric recalibration, firearms hit point detection using thermal imaging camera, IR laser spot tracking algorithm for after action review analysis, and implementation of ballistics equations. The combination of the abovementioned advantages in a single multimedia firearms training system creates a comprehensive solution for detecting and tracking of the target point usable for shooting training systems and improving intervention tactics of uniformed services. The introduced algorithms of geometric and photometric recalibration allow the use of economically viable commercially available projectors for systems that require long and intensive use without most of the negative impacts on color mapping of existing multi-projector multimedia shooting range systems. The article presents the results of the developed algorithms and their application in real training systems.

Keywords: firearms shot detection, geometric recalibration, photometric recalibration, IR tracking algorithm, thermography, ballistics

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Authors: Sudhir Kumar Tiwari

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The paper demonstrates a methodology that can be used at an early design stage of any conventional aircraft. This research activity assesses the feasibility derivation of methodology for aircraft loads estimation during the various phases of design for a transport category aircraft by utilizing potential of using commercial finite element analysis software, which may drive significant time saving. Early Design phase have limited data and quick changing configuration results in handling of large number of load cases. It is useful to idealize the aircraft as a connection of beams, which can be very accurately modelled using finite element analysis (beam elements). This research explores the correct approach towards idealizing an aircraft using beam elements. FEM Techniques like inertia relief were studied for implementation during course of work. The correct boundary condition technique envisaged for generation of shear force, bending moment and torque diagrams for the aircraft. The possible applications of this approach are the aircraft design process, which have been investigated.

Keywords: multi-disciplinary optimization, aircraft load, finite element analysis, stick model

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Authors: Abdulkerim Ilgun, Ahmad Javid Zia

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In developing countries, the urban populations are increasing rapidly and with this increment the residential areas are experiencing major problems. Construction of high-rise buildings in confined spaces is one of the most practical solutions for this problem. However, by living in high-rise buildings and sharing common residential areas, residents will face many problems. Irritating sound problem which is known as noise is one of the major problems mentioned above. The second most important problem is the weight of the high-rise buildings which makes the structure more vulnerable to earthquakes. To decrease earthquake loads it’s very important to decrease the weight of the buildings. To solve the problem of noise and keep the building weight at minimum level, experimentally designed soundproof gypsum partition wall which has optimum thickness has been used in high-rise story building and the results have been compared with ordinary brick partition walls. In this compression the effect of weights of soundproof gypsum walls and ordinary brick walls in accordance to structural engineering have been investigated.

Keywords: cellubor, gypsum board, gypsum partition walls, light partition walls, noise, sound

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Authors: A. T. Muruviwa

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Empirical studies of the current CSR agenda have been dominated by literature from the North at the expense of the nations from the South where most TNCs are located. Therefore, owing to the limitations of the current discourse that is dominated by Western ideas such as voluntarism, philanthropy, business case and economic gains, scholars have been calling for a new CSR agenda that is South-centred and addresses the needs of developing nations. The development theme has dominated in the recent literature as scholars concerned with the relationship between business and society have tried to understand its relationship with CSR. Despite a plethora of literature on the roles of corporations in local communities and the impact of CSR initiatives, there is lack of adequate empirical evidence to help us understand the nexus between CSR and development. For all the claims made about the positive and negative consequences of CSR, there is surprisingly little information about the outcomes it delivers. This study is a response to these claims made about the developmental aspect of CSR in developing countries. It offers some empirical bases for assessing the major CSR projects that have been fulfilled by a major mining company, Zimplats in Mhondoro-Ngezi Zimbabwe. The neo-liberal idea of capitalism and market dominations has empowered TNCs to stamp their authority in the developing countries. TNCs have made their mark in developing nations as they stamp their global private authority, rivalling or implicitly challenging the state in many functions. This dominance of corporate power raises great concerns over their tendencies of abuses in terms of environmental, social and human rights concerns as well as how to make them increasingly accountable. The hegemonic power of TNCs in the developing countries has had a tremendous impact on the overall CSR practices. While TNCs are key drivers of globalization they may be acting responsibly in their Global Northern home countries where there is a combination of legal mechanisms and the fear of civil society activism associated with corporate scandals. Using a triangulated approach in which both qualitative and quantitative methods were used the study found out that most CSR projects in Zimbabwe are dominated and directed by Zimplats because of the power it possesses. Most of the major CSR projects are beneficial to the mining company as they serve the business plans of the mining company. What was deduced from the study is that the infrastructural development initiatives by Zimplats confirm that CSR is a tool to advance business obligations. This shows that although proponents of CSR might claim that business has a mandate for social obligations to society, we need not to forget the dominant idea that the primary function of CSR is to enhance the firm’s profitability.

Keywords: hegemonic power, projects, reciprocity, stakeholders

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Authors: S. M. Rifat, André L. Marchildon, Mark F. Tachie

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The effect of upstream surface roughness over a smooth forward facing step in an open channel was investigated using a particle image velocimetry technique. Three different upstream surface topographies consisting of hydraulically smooth wall, sandpaper 36 grit and sand grains were examined. Besides the wall roughness conditions, all other upstream flow characteristics were kept constant. It was also observed that upstream roughness decreased the approach velocity by 2% and 10% but increased the turbulence intensity by 14% and 35% at the wall-normal distance corresponding to the top plane of the step compared to smooth upstream. The results showed that roughness decreased the reattachment lengths by 14% and 30% compared to smooth upstream. Although the magnitudes of maximum positive and negative Reynolds shear stress in separated and reattached region were 0.02Ue for all the cases, the physical size of both the maximum and minimum contour levels were decreased by increasing upstream roughness.

Keywords: forward facing step, open channel, separated and reattached turbulent flows, wall roughness

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Authors: Lee Artz

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Based on content analyses of major US media, immediately following the George Floyd killing in May 2020, some mayors and local, state, and national officials offered favorable representations of protests against police violence. As the protest movement grew to historic proportions with 26 million joining actions in large cities and small towns, dominant representations of racism by elected officials and leading media shifted—replacing both the voices and demands of protestors with representations by elected officials. Major media quoted Black mayors and Congressional representatives who emphasized concerns about looting and the disruption of public safety. Media coverage privileged elected officials who criticized movement demands for defunding police and deplored isolated instances of property damaged by protestors. Subsequently, public opinion polls saw an increase in concern for law and order tropes and a decrease in support for protests against police violence. Black Lives Matter and local organizations had no coordinated response and no effective means of communication to counter dominant representations voiced by politicians and globally disseminated by major media. Politician and media-instigated public opinion shifts indicate that social movements need their own means of communication and collective decision-making--both of which were largely missing from Black Lives Matter leaders, leading to disaffection and a political split by more than 20 local affiliates. By itself, social media by myriad individuals and groups had limited purchase as a means for social movement communication and organization. Lacking a collaborative, coordinated strategy, organization, and independent media, the loose network of Black Lives Matter groups was unable to offer more accurate, democratic, and favorable representations of protests and their demands for more justice and equality. The fight for equality was diverted by the fight for representation.

Keywords: black lives matter, public opinion, racism, representations, social movements

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Authors: Mikhail Gritskevich, Sebastian Hohenstein

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The paper presents the results of a detailed assessment of several modern Reynolds Averaged Navier-Stokes (RANS) turbulence models for prediction of C3X vane film cooling at various injection regimes. Three models are considered, namely the Shear Stress Transport (SST) model, the modification of the SST model accounting for the streamlines curvature (SST-CC), and the Explicit Algebraic Reynolds Stress Model (EARSM). It is shown that all the considered models face with a problem in prediction of the adiabatic effectiveness in the vicinity of the cooling holes; however, accounting for the Reynolds stress anisotropy within the EARSM model noticeably increases the solution accuracy. On the other hand, further downstream all the models provide a reasonable agreement with the experimental data for the adiabatic effectiveness and among the considered models the most accurate results are obtained with the use EARMS.

Keywords: discrete holes film cooling, Reynolds Averaged Navier-Stokes (RANS), Reynolds stress tensor anisotropy, turbulent heat transfer

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Authors: Kanzumba Kusakana

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The Democratic Republic of Congo (DRC) is currently experiencing a general energy crisis due to lack of proper investment and management in the energy sector. 93, 6% of the country is highly dependent on wood fuels as main source of energy having severe impacts such as deforestation and general degradation of the environment. On the other hand, the major share of the electricity produced mainly from ill-conditioned hydro and thermal power stations is principally used to supply the industrial sector as well as very few urban areas. Nevertheless, DRC possesses huge potential in renewable resources such as hydropower, biomass, methane gas, solar geothermal and moderate wind potential that can be used for energy generation. Recently the country has initiated projects to build decentralized micro hydropower station to supply remotes and isolated areas; to rehabilitate its existent main hydropower plants and transmission lines as well as to extend its current generation capacity by building new hydropower stations able to respond to a major part of the African continent energy needs. This paper presents a comprehensive review of current energy resources as well as of the electricity situation in DRC. Recent energy projects, the energy policy as well as the energy challenges in the DRC are also presented.

Keywords: energy, biomass, hydro power, renewable energy, energy policy, Democratic Republic of Congo

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Authors: Debraj Adhikari, Resham Bahadur Thapa, Samudra Lal Joshi, Jason Jinping Du, Sundar Tiwari

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The purpose of this study was to keep a record of fruit fly species (Tephritidae: Diptera) in the sweet orange orchards of Sindhuli district, Nepal. Male fruit fly species were trapped and collected fortnightly using para-pheromone lures (methyl eugenol and cue lure) in Steiner traps at 25 orchards starting in March 2019 and continuing until February 2021. During the monitoring period, there was a significant variation in the occurrence of the fruit fly species. Fruit flies were captured in greater numbers during warm and rainy months (June, July, August, September) than during dry and winter months (December, January, February). Higher numbers of fruit flies were trapped in methyl eugenol than cue lure traps. Bactrocera dorsalis, B. zonata were major fruit fly species trapped in the methyl eugenol trap. Whereas, Zeugodacus tau, Z. cucurbitae, Z. scutellaris, and Dacus longicornis were major fruit fly species trapped in the cue lure trap. The findings of this study could be used to develop a long-term pest management strategy for the agro-ecological system.

Keywords: bactrocera, cue lure, methyl eugenol, monitoring, zeugodacus

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Authors: Ana Gavardashvili

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The field-and-scientific studies to evaluate the modern ecological state in the water area of the estuaries of the major water-abundant rivers in the coastal line of the Black Sea (Chorokhi, Kintrishi, Natanebi, Supsa, Khobistskali, Rioni and Enguri) and sea ports (Batumi, Poti) and sea terminals of the oil pipeline (Baku-Tbilisi-Supsa, Kulevi) were accomplished in the months of June and July of 2015. GPS coordinates and GIS programs were used to fix the areas of the estuaries of the above-listed rivers on a digital map, with their values varying within the limits of 0,861 and 20,390 km2. Water samples from the Black Sea were taken from the river estuaries and sea ports during the field works, with their statistical series of 125 points. The temperatures of air (t2) and water in the Black Sea (t1) were measured locally, and their relative value is (t1 /t2 ) = 0,69 – 0,92. 125 water samples taken from the study object in the Black Sea coastal line were subject to laboratory analysis, and it was established that the Black Sea acidity (pH) changes within the limits of 7,71 – 8,22 in the river estuaries and within 8,42 - 8,65 in the port water areas and at oil terminals. As for the Sea water salinity index (TDS), it changes within the limits of 6,15 – 12,67 in the river estuaries, and (TDS) = 11,80 – 13,67 in the port water areas and at oil terminals. By taking the gained data and climatic changes into account, by using the theories of reliability and risk at the following stage, the nature of the changes of the function of the Black Sea ecological parameters will be established.

Keywords: acidity, estuary, salinity, sea

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Authors: Mohamed Hussein

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This paper studies the effect of boundary retaining walls properties on the behavior of the raft foundation. Commercial software program Sap2000 was used in this study. The soil was presented as continuous media (follows the Winkler assumption). Shell elements were employed to model the raft plate. A parametric study has been carried out to examine the effect of boundary retaining walls properties on the behavior of raft plate. These parameters namely, height of the boundary retaining walls, thickness of the boundary retaining walls, flexural rigidity of raft plate, bearing capacity of supporting soil and the earth pressure of boundary soil. The main results which were obtained from this study are positive, negative bending moment, shear stress and deflection in raft plate, where these parameters are considered the main parameters used in design of raft foundation. It was concluded that the boundary retaining walls have a significant effect on the straining actions in raft plate.

Keywords: Sap2000, boundary retaining walls, raft foundations, Winkler model, flexural rigidity

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Authors: Seok-In Bae, Young-Hoon Lee, Ji-Hwan Kim

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Due to the asymmetry of the material properties of the Functionally Graded Materials(FGMs) in the thickness direction, neutral surface of the model is not the same as the mid-plane of the symmetric structure. In order to investigate the thermal bucking behavior of FGMs, neutral surface is chosen as a reference plane. In the model, material properties are assumed to be temperature dependent, and varied continuously in the thickness direction of the plate. Further, the effective material properties such as Young’s modulus and Poisson’s ratio are homogenized using Mori-Tanaka scheme which considers the interaction among adjacent inclusions. In this work, the finite element methods are used, and the first-order shear deformation theory of plate are accounted. The thermal loads are assumed to be uniform, linear and non-linear distribution through the thickness directions, respectively. Also, the effects of various parameters for thermal buckling behavior of FGM panel are discussed in detail.

Keywords: functionally graded plate, thermal buckling analysis, neutral surface

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Authors: Vladimir Stojanović, Marko D. Petković

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The vibration of a complex bogie system that moves on along the high order shear deformable beam on a viscoelastic foundation is studied. The complex bogie system has been modeled by elastically connected rigid bars on an identical supports. Elastic coupling between bars is introduced to simulate rigidly or flexibly (transversal or/and rotational) connection. Identical supports are modeled as a system of attached spring and dashpot to the bar on one side and interact with the beam through the concentrated mass on the other side. It is assumed that the masses and the beam are always in contact. New analytically determined critical velocity of the system is presented. It is analyzed the case when the complex bogie system exceeds the minimum phase velocity of waves in the beam when the vibration of the system may become unstable. Effect of an elastic coupling between bars on the stability of the system has been analyzed. The instability regions are found for the complex bogie system by applying the principle of the argument and D-decomposition method.

Keywords: Reddy-Bickford beam, D-decomposition method, principle of argument, critical velocity

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Authors: Alvaro Quino, Roger Trejo, Gary Duran, Jordy Viso

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This article presents a study on the lightening and improvement of properties of soil extracted in the province of Talara in the department of Piura -Peru, to be used in filling in the construction of embankments for roads. This soft soil has a high percentage of elastic settlement and consolidation settlement. Currently, there are different methods that seek to mitigate the impact of this problem, which have achieved favorable results. As a contribution to these investigations, we propose the use of two lightening materials to be used in the filling of embankments; these materials are expanded polystyrene beads (EPS) and rice husk ash (RHA). Favorable results were obtained, such as a reduction of 14.34% of the volumetric weight, so the settlement will be reduced. In addition, it is observed that as the RHA dosage increases, the shear resistance increases. In this article, soil mechanics tests were performed to determine the effectiveness of this method in lightening and improving properties for the soil under study.

Keywords: sandy clay soils, rice husk ash, expanded polystyrene, soft soils

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Authors: Bao Thach Nguyen, Abbas Mohajerani

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The California bearing ratio (CBR) has been acknowledged as an important parameter to characterize the bearing capacity of earth structures, such as earth dams, road embankments, airport runways, bridge abutments, and pavements. Technically, the CBR test can be carried out in the laboratory or in the field. The CBR test is time-consuming and is infrequently performed due to the equipment needed and the fact that the field moisture content keeps changing over time. Over the years, many correlations have been developed for the prediction of CBR by various researchers, including the dynamic cone penetrometer, undrained shear strength, and Clegg impact hammer. This paper reports and discusses some of the results from a study on the prediction of CBR. In the current study, the CBR test was performed in the laboratory on some fine-grained subgrade soils collected from various locations in Victoria. Based on the test results, a satisfactory empirical correlation was found between the CBR and the physical properties of the experimental soils.

Keywords: California bearing ratio, fine-grained soils, soil physical properties, pavement, soil test

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Authors: Hisham Elmouazen, Xiaobing Zhang

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In regenerative-cooled rocket engines, understanding the coolant behaviour within cooling channels is essential to enhance engine performance and maintain chamber walls at low temperatures. However, modelling and testing the rocket engine's cooling channels is challenging due to the high temperature of the chamber walls, supercritical flow, and high Reynolds number. Therefore, a numerical analysis of five different V-rib cross-sections to optimize rocket engine cooling channels' performance is developed and validated in this work. Three-dimensional CFD simulations are employed by the Shear Stress Transport (k- ω) turbulent model at Reynolds number 42,500. The study findings illustrate that the V-ribbed channel performance is optimized by 59.5% relative to the plain/flat channel. Additionally, the chamber wall temperature is decreased to 726.4 K, and the right-angle trapezoidal V-rib (Case 4) improves thermal augmentation up to 74.3 % with a slightly high friction factor.

Keywords: computational fluid dynamics CFD, regenerative-cooled system, thermal performance, V-rib cross-sections

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Authors: Gehan Hussein, Hala Agha, Rasha Abdelraof, Marina George, Antoine Fakhri

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Background: β-Thalassemia major (TM) and sickle cell disease (SCD) are inherited hemoglobin disorders resulting in chronic hemolytic anemia. Cardiovascular involvement is an important cause of morbidity and mortality in these groups of patients. The narrow border is between overt myocardial dysfunction and clinically silent left ventricular (LV) and / or right ventricular (RV) dysfunction in those patients. 3 D Speckle tracking echocardiography (3D STE) is a novel method for the detection of subclinical myocardial involvement. We aimed to study myocardial affection in SCD and TM using 3D STE, comparing it with conventional echocardiography, correlate it with serum ferritin level and lactate dehydrogenase (LDH). Methodology: Thirty SCD and thirty β TM patients, age range 4-18 years, were compared to 30 healthy age and sex matched control group. Cases were subjected to clinical examination, laboratory measurement of hemoglobin level, serum ferritin, and LDH. Transthoracic color Doppler echocardiography, 3D STE, tissue Doppler echocardiography, and aortic speckle tracking were performed. Results: significant reduction in global longitudinal strain (GLS), global circumferential strain (GCS), and global area strain (GAS) in SCD and TM than control (P value <0.001) there was significantly lower aortic speckle tracking in patients with TM and SCD than control (P value< 0.001). LDH was significantly higher in SCD than both TM and control and it correlated significantly positive mitral inflow E, (p value:0.022 and 0.072. r: 0.416 and -0.333 respectively) lateral E/E’ (p value.<0.001and 0.818. r. 0.618 and -0. 044.respectively) and septal E/E’ (p value 0.007 and 0.753& r value 0.485 and -0.060 respectively) in SCD but not TM and significant negative correlation between LDH and aortic root speckle tracking (value 0.681& r. -0.078.). The potential diagnostic accuracy of LDH in predicting vascular dysfunction as represented by aortic root GCS with a sensitivity 74% and aortic root GCS was predictive of LV dysfunction in SCD patients with sensitivity 100% Conclusion: 3D STE LV and RV systolic dysfunction in spite of their normal values by conventional echocardiography. SCD showed significantly lower right ventricular dysfunction and aortic root GCS than TM and control. LDH can be used to screen patients for cardiac dysfunction in SCD, not in TM

Keywords: thalassemia major, sickle cell disease, 3d speckle tracking echocardiography, LDH

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Authors: Tsung-Lin Hsieh, Jiun-Jen Chen, Yuhao Kang

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Metal-organic frameworks (MOFs) have drawn scientists’ attention for decades due to its high specific surface area, tunable pore size, and relatively low temperature for regeneration. Bearing with those mentioned properties, MOFs has been widely used in various applications, such as adsorption/separation and catalysis. However, the current challenge for practical use of MOFs is to effectively shape these crystalline powder material into controllable forms such as pellets, granules, and monoliths with sufficient mechanical and chemical stability, while maintaining the excellent properties of MOFs powders. Herein, we have successfully synthesized an Al-based MOF powder which exhibits a high water capacity at relatively low humidity conditions and relatively low temperature for regeneration. Then the synthesized Al-MOF was shaped into granules with particle size of 2-4 mm by (1) tumbling granulation, (2) High shear mixing granulation, and (3) Extrusion techniques. Finally, the water vapor adsorption rate and crush strength of Al-MOF granules by different shaping techniques were measured and compared.

Keywords: granulation, granules, metal-organic frameworks, water vapor adsorption

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Authors: R. I. Liban, N. Tayşi

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This paper deals with a nonlinear finite element analysis to examine the behavior up to failure of cantilever composite steel-concrete beams which are prestressed externally. 'Pre-' means stressing the high strength external tendons in the steel beam section before the concrete slab is added. The composite beam contains a concrete slab which is connected together with steel I-beam by means of perfect shear connectors between the concrete slab and the steel beam which is subjected to static loading. A finite element analysis will be done to study the effects of external prestressed tendons on the composite steel-concrete beams by locating the tendons in different locations (profiles). ANSYS version 12.1 computer program is being used to analyze the represented three-dimensional model of the cantilever composite beam. This model gives all these outputs, mainly load-displacement behavior of the cantilever end and in the middle span of the simple support part.

Keywords: composite steel-concrete beams, external prestressing, finite element analysis, ANSYS

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Authors: Berkay Ergene, Çağın Bolat

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In this study, we mainly focused on a simulation study regarding composite footbed in order to contribute to shoe industry. As a footbed, e-glass fiber reinforced polyurethane was determined since polyurethane based materials are already used for footbed in shoe manufacturing frequently. Flat, elliptical and rectangular grooved shoe soles were modeled and analyzed separately as TPU, 10% glass fiber reinforced, 30% glass fiber reinforced and 50% glass fiber reinforced materials according to their properties under three point bending and compression situations to determine the relationship between model, material type and mechanical behaviours of composite model. ANSYS 14.0 APDL mechanical structural module is utilized in all simulations and analyzed stress and strain distributions for different footbed models and materials. Furthermore, materials constants like young modulus, shear modulus, Poisson ratio and density of the composites were calculated theoretically by using composite mixture rule and interpreted for mechanical aspects.

Keywords: composite, elastic behaviour, footbed, simulation

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Authors: Nabila Jaman, K. E. Hoque, S. Sawall, M. Ferdows

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Coronary artery disease (CAD) is one of the most lethal diseases of the cardiovascular diseases. Coronary arteries stenosis and bifurcation angles closely interact for myocardial infarction. We want to use computer-aided design model coupled with computational hemodynamics (CHD) simulation for detecting several types of coronary artery stenosis with different locations in an idealized model for identifying virtual fractional flow reserve (vFFR). The vFFR provides us the information about the severity of stenosis in the computational models. Another goal is that we want to imitate patient-specific computed tomography coronary artery angiography model for constructing our idealized models with different left anterior descending (LAD) and left circumflex (LCx) bifurcation angles. Further, we want to analyze whether the bifurcation angles has an impact on the creation of narrowness in coronary arteries or not. The numerical simulation provides the CHD parameters such as wall shear stress (WSS), velocity magnitude and pressure gradient (PGD) that allow us the information of stenosis condition in the computational domain.

Keywords: CAD, CHD, vFFR, bifurcation angles, coronary stenosis

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Authors: Ghusen al-Kafri, Mohammed Ali Abdallah Elsageer, Ahmed Mohamed Hadya Alsdaai, Abdeimanam Salhien Salih Khalifa

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In this paper, external reinforcement to enhance a reinforced concrete structure performance has been done using externally bonded steel plate. This technique has been reported effective in enhancing the strength of reinforced concrete beam, a study to determine the effectiveness of steel plate as an external reinforcement was carried out. A total of two groups of beams and one group content five beams, each 750 mm long, 150 mm wide, and 150 mm deep were cast, strengthened and tested till failure under two point loads. One beam was act as a control beam without strengthening and other four beams were strengthened with steel plate at a different arrangement. Other group beams were strengthened with steel plate in shear zone and also strengthened at bottom as first group. The behaviours of the strengthened beams were studied through their load-deflection characteristic upon bending, cracking and mode of failure. The results confirmed that all steel plate arrangements enhanced the strength of the reinforced concrete beam, the positioning of the steel plate affect the moment carrying capacity of the beam.

Keywords: beams, bending, beflection, steel plates

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Authors: Wenpeng You, Maciej Henneberg

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Background: Sugar consumption has been overwhelmingly advocated as a major dietary offender to obesity prevalence. Meat intake has been hypothesized as an obesity contributor in previous publications, but a moderate amount of meat to be included in our daily diet still has been suggested in many dietary guidelines. Comparable sugar and meat exposure data were obtained to assess the difference in relationships between the two major food groups and obesity prevalence at population level. Methods: Population level estimates of obesity and overweight rates, per capita per day exposure of major food groups (meat, sugar, starch crops, fibers, fats and fruits) and total calories, per capita per year GDP, urbanization and physical inactivity prevalence rate were extracted and matched for statistical analysis. Correlation coefficient (Pearson and partial) comparisons with Fisher’s r-to-z transformation and β range (β ± 2 SE) and overlapping in multiple linear regression (Enter and Stepwise) were used to examine potential differences in the relationships between obesity prevalence and sugar exposure and meat exposure respectively. Results: Pearson and partial correlations (controlled for total calories, physical inactivity prevalence, GDP and urbanization) analyses revealed that sugar and meat exposures correlated to obesity and overweight prevalence significantly. Fisher's r-to-z transformation did not show statistically significant difference in Pearson correlation coefficients (z=-0.53, p=0.5961) or partial correlation coefficients (z=-0.04, p=0.9681) between obesity prevalence and both sugar exposure and meat exposure. Both Enter and Stepwise models in multiple linear regression analysis showed that sugar and meat exposure were most significant predictors of obesity prevalence. Great β range overlapping in the Enter (0.289-0.573) and Stepwise (0.294-0.582) models indicated statistically sugar and meat exposure correlated to obesity without significant difference. Conclusion: Worldwide sugar and meat exposure correlated to obesity prevalence at the same extent. Like sugar, minimal meat exposure should also be suggested in the dietary guidelines.

Keywords: meat, sugar, obesity, energy surplus, meat protein, fats, insulin resistance

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Authors: Abdulaziz Almustafa

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Considering the critical role permanence has on predictions related to the contextual interference effect on laboratory and field research, this study sought to determine whether the paradigm of the effect depends on the complexity of the skill during the acquisition and transfer phases. The purpose of the present study was to investigate the effects of contextual interference CI by extending previous laboratory and field research with adult athletes through the acquisition and transfer phases. Male (n=60) athletes age 18-22 years-old, were chosen randomly from Eastern Province Clubs. They were assigned to complete blocked, random, or serial practices. Analysis of variance with repeated measures MANOVA indicated that, the results did not support the notion of CI. There were no significant differences in acquisition phase between blocked, serial and random practice groups. During the transfer phase, there were no major differences between the practice groups. Apparently, due to the task complexity, participants were probably confused and not able to use the advantages of contextual interference. This is another contradictory result to contextual interference effects in acquisition and transfer phases in sport settings. One major factor that can influence the effect of contextual interference is task characteristics as the nature of level of difficulty in sport-related skill.

Keywords: contextual interference, acquisition, transfer, task difficulty

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Authors: Geumchan Hwang

Abstract:

Professional sport leagues in Europe and North America are shut down due to novel coronavirus disease (COVID-19) outbreak. Football leagues in Europe (e.g., La Liga, English Premier League, Bundesliga, Serie A, and Ligue 1) and big four professional sport leagues in North America (e.g., National Football League, Major League Baseball, National Basketball Association, and National Hockey League) are indefinitely suspended or delayed. COVID-19 outbreak has a growing negative impact on economics of sport leagues. For example, loss of revenue in Europe’s top five leagues due to the COVID-19 pandemic was estimated at € 4 billion and loss of revenue in the NBA was estimated at $650 million as of March 2020. In the unprecedented difficult situation, sport teams and leagues try to communicate with sport fans through diverse media platforms. In sport, however, very few studies have been done regarding how sport organizations effectively communicate with sport fans during pandemics, such as COVID-19 outbreak. Understanding sport organizations’ crisis communication is important to develop effective crisis management strategies for sport organizations. Therefore, the purpose of the study is to examine how sport organizations communicate with sport fans via online platforms in COVID-19 outbreak and how sport fans evaluate their communication strategies. 9 official sport league sites (i.e., five major football leagues in Europe and four major sport leagues in North America) and COVID-19 news articles published between January and June in 2020 will be analyzed in terms of coronavirus information, teams and players’ live update, fan interaction, fan support, and community engagement. In addition, comments posted on social media sites (i.e., Facebook and Twitter) of major sport leagues will be also analyzed to examine how sport fans perceive online messages provided by sport leagues as an effective communication strategy. To measure the effectiveness of crisis communication performance, five components (i.e., prompt, compassionate, honest, informative, and interactive) of crisis communication will be collected from leagues’ official websites information and social media posts. Upon completing data collection, content analysis method will be used to evaluate effectiveness of crisis communication among 9 professional sport leagues. The results of the study will provide athletic directors, administrators, and public relations managers in sport organizations with practical information regarding how athlete celebrities and sport organizations should interact with their fans in pandemic situations. In particular, this study will contribute to developing specific crisis management plan for sport organizations. For instance, football teams and leagues in Europe will be able to create standard manuals to minimize damages caused by disease outbreak, such as COVID-19 outbreak.

Keywords: COVID-19, communication, sport leagues, fans

Procedia PDF Downloads 145

Authors: Ratul Das

Abstract:

The present experimental study insights the decontamination of instantaneous velocity fluctuations captured by Acoustic Doppler Velocimeter (ADV) in gravel-bed streams to ascertain near-bed turbulence for low Reynolds number. The interference between incidental and reflected pulses produce spikes in the ADV data especially in the near-bed flow zone and therefore filtering the data are very essential. Nortek’s Vectrino four-receiver ADV probe was used to capture the instantaneous three-dimensional velocity fluctuations over a non-cohesive bed. A spike removal algorithm based on the acceleration threshold method was applied to note the bed roughness and its influence on velocity fluctuations and velocity power spectra in the carrier fluid. The velocity power spectra of despiked signals with a best combination of velocity threshold (VT) and acceleration threshold (AT) are proposed which ascertained velocity power spectra a satisfactory fit with the Kolmogorov “–5/3 scaling-law” in the inertial sub-range. Also, velocity distributions below the roughness crest level fairly follows a third-degree polynomial series.

Keywords: acoustic doppler velocimeter, gravel-bed, spike removal, reynolds shear stress, near-bed turbulence, velocity power spectra

Procedia PDF Downloads 303

Authors: F. Atheer, Al-Saoudi, Robin Kalfat, Riadh Al-Mahaidi

Abstract:

Over the last two decades, externally bonded fiber reinforced polymer (FRP) composites bonded to concrete substrates has become a popular method for strengthening reinforced concrete (RC) highway and railway bridges. Such structures are exposed to severe cyclic loading throughout their lifetime often resulting in fatigue damage to structural components and a reduction in the service life of the structure. Since experimental and numerical results on the fatigue performance of FRP-to-concrete joints are still limited, the current research focuses on assessing the fatigue performance of externally bonded FRP-to-concrete joints using a direct shear test. Some early results indicate that the stress ratio and the applied cyclic stress level have a direct influence on the fatigue life of the externally bonded FRP. In addition, a calibrated finite element model is developed to provide further insight into the influence of certain parameters such as: concrete strength, FRP thickness, number of cycles, frequency and stiffness on the fatigue life of the FRP-to-concrete joints.

Keywords: FRP, concrete bond, control, fatigue, finite element model

Procedia PDF Downloads 452

Authors: Mohamed N. Al-Arifi, Hessa Othman Al-Husein, Mostafa Q. Al Shamiri, Ragab Said, Syed Wajid, Salmeen D. Babelghaith

Abstract:

Polypharmacy was defined as a taking more than 4 medications per single patients (minor polypharmacy), patients who are taking more than 10 medications we considered as a major polypharmacy. This study was aimed to evaluate the prevalence of polypharmacy in elderly Saudi cardiac patient. A retrospective observational study was carried out at the department of CCU and cardiology unit of the King Fahad cardiac centre (KFCC) in King Khalid university hospital from May 2012 to October 2012. All Parameters was analyzed by using Statistical Packages for Social Science (SPSS) to conclude the result; tests of association were performed using the chi-square statistic. The mean age of patients was 70.1 ± 7.75 years, more than half 83 (51.6%) were males. The highest frequency of chronic diseases found were hypertension (91.0%) followed by, dyslipidemia (74.9%), and diabetes mellitus. Results showed that 82% had polypharmacy (>4 drugs) during the study period, and 47.9% had major polypharmacy. The incidence of inappropriate drug use was found to be higher with men than female (p = 0.984). In conclusion, this study revealed that high prevalence of polypharmacy and potentially inappropriate medications in elderly Saudi cardiac inpatients.

Keywords: cardiac inpatients, medications, polypharmacy, prevalence

Procedia PDF Downloads 739