Search results for: effect evaluation

Authors: Sally Hosny, Mona G. Ibrahim, N. K. Hassan

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Fiber reinforced polymers (FRP) is one of the most environmentally method for strengthening and retrofitting steel structure buildings. The behaviour of flexural strengthened steel I-beams using FRP was investigated. The finite element (FE) models were developed using ANSYS® as verification cases to simulate the experimental behaviour of using FRP strips to flexure strengthen steel I-beam. Two experimental studies were selected for verification; first examined the effect of different thicknesses and modulus of elasticity while the second studied the effect of applying different carbon fiber reinforced polymers (CFRP) bond lengths. The proposed FE models were in good agreement with the experimental results in terms of failure modes, load bearing capacities and strain distribution on CFRP strips. The verified FE models can be utilized to conduct a parametric study where various widths (40, 50, 60, 70 and 80 mm), thickness (1.2, 2 and 4 mm) and lengths (1500, 1700 and 1800 mm) of CFRP were analyzed. The results presented clearly revealed that the load bearing capacity was significantly increased (+7%) when the width and thickness were increased. However, load bearing capacity was slightly affected using longer CFRP strips. Moreover, applying another glass fiber reinforced polymers (GFRP) of 1500 mm in length, 50 mm in width and thicknesses of 1.2, 2 and 4 mm were investigated. Load bearing capacity of strengthened I-beams using GFRP is less than CFRP by average 8%. Statistical analysis has been conducted using Minitab®.

Keywords: FRP, strengthened steel I-beams, flexural, FEM, ANSYS

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Authors: Khalid. M. O. Elmabrok, M. L. Burby, G. G. Nasr

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Flow instability during gas lift operation is caused by three major phenomena – the density wave oscillation, the casing heading pressure and the flow perturbation within the two-phase flow region. This paper focuses on the causes and the effect of flow instability during gas lift operation and suggests ways to control it in order to maximise productivity during gas lift operations. A laboratory-scale two-phase flow system to study the effects of flow perturbation was designed and built. The apparatus is comprised of a 2 m long by 66 mm ID transparent PVC pipe with air injection point situated at 0.1 m above the base of the pipe. This is the point where stabilised bubbles were visibly clear after injection. Air is injected into the water filled transparent pipe at different flow rates and pressures. The behavior of the different sizes of the bubbles generated within the two-phase region was captured using a digital camera and the images were analysed using the advanced image processing package. It was observed that the average maximum bubbles sizes increased with the increase in the length of the vertical pipe column from 29.72 to 47 mm. The increase in air injection pressure from 0.5 to 3 bars increased the bubble sizes from 29.72 mm to 44.17 mm and then decreasing when the pressure reaches 4 bars. It was observed that at higher bubble velocity of 6.7 m/s, larger diameter bubbles coalesce and burst due to high agitation and collision with each other. This collapse of the bubbles causes pressure drop and reverse flow within two phase flow and is the main cause of the flow instability phenomena.

Keywords: gas lift instability, bubbles forming, bubbles collapsing, image processing

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Authors: T. J. Ellapen, N. Acampora, S. Dawson, J. Arling, C. Van Niekerk, H. J. Van Heerden

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Objectives: To determine the comparative proprioceptive performance of injured versus non-injured adolescent female hockey players when wearing an ankle brace. Methods: Data were collected from 100 high school players who belonged to the Highway Secondary School KZN Hockey league via voluntary parental informed consent and player assent. Players completed an injury questionnaire probing the prevalence and nature of hockey injuries (March-August 2013). Subsequently players completed a Biodex proprioceptive test with and without an ankle brace. Probability was set at p≤ 0.05. Results: Twenty-two players sustained ankle injuries within the six months (p<0.001). Injured players performed similarly without bracing Right Anterior Posterior Index (RAPI): 2.8±0.9; Right Medial Lateral Index (RMLI): 1.9±0.7; Left Anterior Posterior Index (LAPI) LAPI: 2.7; Left Medial Lateral Index (LMLI): 1.7±0.6) as compared to bracing (RAPI: 2.7±1.4; RMLI: 1.8±0.6; LAPI: 2.6±1.0; LMLI: 1.5±0.6) (p>0.05). However, bracing (RAPI: 2.2±0.8; RMLI: 1.5±0.5; LAPI: 2.4±0.9; MLI: 1.5±0.5) improved the ankle stability of the non-injured group as compared to their unbraced performance (RAPI: 2.5±1.0; RMLI: 1.8±0.8; LAPI: 2.8±1.1; LMLI: 1.8±0.6) (p<0.05). Conclusion: Ankle bracing did not enhance the stability of injured ankles. However ankle bracing has an ergogenic effect enhancing the stability of healthy ankles.

Keywords: hockey, proprioception, ankle, bracing

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Authors: Z. Chen, C. S. Poon

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In Hong Kong, about 1,000 tonnes of sewage sludge were produced every day in 2014 representing a major fraction of the total solid municipal waste. Traditionally, sewage sludge is disposed of at landfills. This disposal method causes environmental issues and uses up precious space in landfills which are becoming saturated one by one. To tackle the disposal problem, Hong Kong government has just built a sewage sludge incinerator. Through incineration the volume of waste can be reduced up to 90% by converting sewage sludge into ash. Whilst sewage sludge ash (SSA) still needs to be disposed of at landfills, research has been conducted at the Hong Kong Polytechnic University on using SSA to substitute cement for the production of construction materials. Results demonstrated that SSA contained many open and isolated pores and thus can reduce the cement dilution effect resulting in only slight decrease in the flexural and compressive strengths of cement mortar. The incorporation of SSA in cement mortar can be up to 20% of the binder, without too much worry about adverse effect on strength development of mortar. There was some enhancement in strength using ground SSA in comparison to the original SSA. The original SSA shortened the relative initial setting time of cement paste but ground SSA caused slight delay in the setting of cement paste. The research also found that increasing the percentage of SSA lead to decreasing workability of cement mortar with the same water/binder ratio, and ground SSA was beneficial to workability although grinding increased the surface area of SSA. This paper summarizes the major findings of the research.

Keywords: cement replacement, construction material, sewage sludge ash, waste recycling

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Authors: Asier Romero Andonegi, Irati De Pablo Delgado

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The objective of this study is to explore the different methodological procedures that are used to obtain information on the early linguistic development of children. To this end, two different methodological procedures were carried out on the same sample: on the one hand, the MacArthur-Bates Communicative Development Inventories, in its adaptations in Spanish and Basque; and on the other hand, longitudinal observation through professional software: ELAN and CHAT. The sample consists of 8 Basque children/ages 16 to 30 months with different mother tongue (L1). The results show the usefulness of inventories in obtaining information on the development of early communication and language skills, but also their limitations mostly focused on the interpretive overvaluation of their children’s lexical development.

Keywords: early language development, language evaluation, lexicon, MacArthur-Bates communicative development inventories

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Authors: Benjawan Saengwichian, Alasdair E. Charles, Philip J. Hyde

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Magnetically controlled growing rods (MCGRs) have been used to stabilise and correct spinal curvature in children to support non-invasive scoliosis adjustment. Although the encapsulated driving components are intended to be isolated from body fluid contact, in vivo corrosion was observed on these components due to sealing mechanism damage. Consequently, a corrosion circuit is created with the body fluids, resulting in malfunction of the lengthening mechanism. Particularly, the chloride ions in blood plasma or cerebrospinal fluid (CSF) may corrode the MCGR alloys, possibly resulting in metal ion release in long-term use. However, there is no data available on the corrosion resistance of spinal implant alloys in CSF. In this study, an in vitro immersion configuration was designed to simulate in vivo corrosion of 440C SS-Ti6Al4V couples. The 440C stainless steel (SS) was heat-treated to investigate the effect of tempering temperature on intergranular corrosion (IGC), while crevice and galvanic corrosion were studied by limiting the clearance of dissimilar couples. Tests were carried out in a neutral artificial cerebrospinal fluid (ACSF) and phosphate-buffered saline (PBS) under aeration and deaeration for 2 months. The composition of the passive films and metal ion release were analysed. The effect of galvanic coupling, pH, dissolved oxygen and anion species on corrosion rates and corrosion mechanisms are discussed based on quantitative and qualitative measurements. The results suggest that ACSF is more aggressive than PBS due to the combination of aggressive chlorides and sulphate anions, while phosphate in PBS acts as an inhibitor to delay corrosion. The presence of Vivianite on the SS surface in PBS lowered the corrosion rate (CR) more than 5 times for aeration and nearly 2 times for deaeration, compared with ACSF. The CR of 440C is dependent on passive film properties varied by tempering temperature and anion species. Although the CR of Ti6Al4V is insignificant, it tends to release more Ti ions in deaerated ACSF than under aeration, about 6 µg/L. It seems the crevice-like design has more effect on macroscopic corrosion than combining the dissimilar couple, whereas IGC is dominantly observed on sensitized microstructure.

Keywords: cerebrospinal fluid, crevice corrosion, intergranular corrosion, magnetically controlled growing rods

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Authors: İlhami Karahanoglu, Oguz Ceylan

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As its well-known definitions; systemic risk refers to whole economic system down-turn movement even collapse together in very severe cases. In fact, it points out the contagion effects of the defaults. Such a risk is can be depicted with the famous Chinese game of falling domino stones. During and after the Bear & Sterns and Lehman Brothers cases, it was well understood that there is a very strong effect of systemic risk in financial services sector. In this study, we concentrate on the existence of systemic risk in Turkish Banking Sector based upon the Halkbank Case during the end month of 2013; there was a political turmoil in Turkey in which the close relatives of the upper politicians were involved in illegal trading activities. In that operation, the CEO of Halkbank was also arrested and in investigation, Halkbank was considered as part of such illegal actions. That operation had an impact on Halkbanks stock value. The Halkbank stock value during that time interval decreased remarkably, the distributional profile of stock return changed and became more volatile as well as more skewed. In this study, the daily returns of 5 leading banks in Turkish banking sector were used to obtain 48 return distributions (for each month, 90-days-back stock value returns are used) of 5 banks for the period 12/2011-12/2013 (pre operation period) and 12/2013-12/2015 (post operation period). When those distributions are compared with timely manner, interestingly; the distribution of the 5 other leading banks in Turkey, public or private, had also distribution profiles which was different from the past 2011-2013 period just like Halkbank. Those 5 big banks, whose stock values are monitored with sub index in Istanbul stock exchange (BIST) as BN10, had more skewed distribution just following the Halkbank stock return movement during the post operation period, with lover mean value and as well higher volatility. In addition, the correlation between the stock value return distributions of the leading banks after Halkbank case, where the returns are more skewed to the left, increased (which is measured in monthly base before and after the operation). The dependence between those banks was stronger under the case where the stock values were falling compared with the normal market condition. Such distributional effect of stock returns between the leading banks in Turkey, which is valid for down sub-market (financial/banking sector) condition, can be evaluated as an evidence for the existence of contagious effect and systemic risk.

Keywords: financial risk, systemic risk, banking sector, return distribution, dependency structure

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Authors: Nassier A. Nassir, Robert Birch, D. Rico Sierra, S. P. Edwardson, G. Dearden, Zhongwei Guan

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The effect of laser surface treatment parameters on the residual strength of titanium alloy has been investigated. The influence of the laser surface treatment on the bonding strength between the titanium and poly-ether-ketone-ketone (PEKK) surfaces was also evaluated and compared to those offered by titanium foils without surface treatment to optimize the laser parameters. Material characterization using an optical microscope was carried out to study the microstructure and to measure the mean roughness value of the titanium surface. The results showed that the surface roughness shows a significant dependency on the laser power parameters in which surface roughness increases with the laser power increment. Moreover, the results of the tensile tests have shown that there is no significant dropping in tensile strength for the treated samples comparing to the virgin ones. In order to optimize the laser parameter as well as the corresponding surface roughness, single-lap shear tests were conducted on pairs of the laser treated titanium stripes. The results showed that the bonding shear strength between titanium alloy and PEKK film increased with the surface roughness increment to a specific limit. After this point, it is interesting to note that there was no significant effect for the laser parameter on the bonding strength. This evidence suggests that it is not necessary to use very high power of laser to treat titanium surface to achieve a good bonding strength between titanium alloy and the PEKK film.

Keywords: bonding strength, laser surface treatment, PEKK, poly-ether-ketone-ketone, titanium alloy

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Authors: S. Abbasi, M. R. Hadian, M. Abdolvahab, M. Jalili, S. H. Jalaei

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Background: Rehabilitation treatments have significant role in reducing the disabilities of Cerebro Vascular Accident (CVA). Due to great role of upper limb in the function of individuals particularly in Activity of Daily Living and the effect of stability of shoulder girdle on hand function, the aim of this study was to study the effects of Progressive Resistive Exercise on shoulder extensor and abductor muscles isometric strengths in adult hemiplegic. Methods: 17 adult hemiplegics patients (50-70 yrs., mean 60/52, SD7/22); with RT side dominancy and 6 months after stroke, participated in this study. All procedures were approved by ethical committee of TUMS and written consents were also taken. Patients were familiarized with the procedure and shoulder extensor and abductor muscles isometric strengths were measured by dynamometer. Results: according to result to our study, shoulder extensor and abductor muscles isometric strengths showed Significant differences between mean scores of pre and post intervention (P<0/05). Progressive Resistive Exercise improved 34% shoulder extensor muscles isometric strength and 27% shoulder abductor muscle isometric strength. Conclusion: Results of our research showed that progressive resistive exercise approach is a useful method for increasing the isometric strength of shoulder extensor and abductor muscles. Therefore, it might be concluded that improvement of strength of shoulder muscles could result in stability in shoulder girdle and consequently might effect on hand function in hemiplegic patients.

Keywords: shoulder extensor muscles isometric strength, shoulder abductor muscles isometric strength, hemiplegic, physical therapy

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Authors: Paata Sitchinava

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It has been studied phenomena subjected on the water physical (hydrophysical, mineralogy containing, specific hydrophysical) class of heavy clay soils of the Colchis lowland, according to various categories and forms of the porous water, which will be the base of the distributed used methods of the engineering practice and reclamation effectiveness evaluation. According to of clay grounds data, it has been chosen three research bases section in the central part of lowland, where has implemented investigation works by using a special program. It has been established, that three of cuts are somewhat identical, and by morphological grounds separated layers are the difference by Gallic quality. It has been implemented suitable laboratory experimental research at the samples taken from the cuts, at the base of these created classification mark of physical-technical characteristic, which is the base of suitable calculation of hydrophysical researches.

Keywords: Colchis lowland, drainage, water, soil-ground

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Authors: Jolanta Tamošaitienė

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The article focuses on a developed comprehensive model to be used in an agile environment for the risk assessment and selection based on multi-attribute methods. The model is based on a multi-attribute evaluation of risk in construction, and the determination of their optimality criterion values are calculated using complex Multiple Criteria Decision-Making methods. The model may be further applied to risk assessment in an agile construction environment. The attributes of risk in a construction project are selected by applying the risk assessment condition to the construction sector, and the construction process efficiency in the construction industry accounts for the agile environment. The paper presents the comprehensive risk assessment model in an agile construction environment. It provides a background and a description of the proposed model and the developed analysis of the comprehensive risk assessment model in an agile construction environment with the criteria.

Keywords: assessment, environment, agile, model, risk

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Authors: Agnese Natali, Francesco Morelli, Walter Salvatore, José Humberto Matias de Paula Filho, Patrick Pol

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In the framework of the evaluation of the applicability of high strength steel to produce thin-walled elements to be used in Automated Rack Supported Warehouses, an experimental campaign is carried outto evaluate the structural performance of typical profile shapes adopted for such purposes and made of high strength steel. Numerical models are developed to fit the observed failure modes, stresses, and deformation patterns, and proper directions are proposed to simplify the numerical simulations to be used in further applications and to evaluate the mechanical behavior and performance of profiles.

Keywords: Steel racks, Automated Rack Supported Warehouse, thin walled cold-formed elements, high strength steel.

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Authors: Ying-Chen Lin, Ching-Ting Hsu, Wei-Hua Ho

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The purpose of this study is to investigate the kinematic characteristics and differences of the snatch barbell trajectory of 53 kg class female weight lifters. We take the 2014 Taiwan College Cup players as examples, and tend to make kinematic applications through the proven weightlifting barbell track system. The competition videos are taken by consumer camcorder with a tripod which set up at the side of the lifter. The results will be discussed in three parts, the first part is various lifting phase, the second part is the compare lifting between success and unsuccessful, and the third part is the outstanding player compare with the general. Conclusion through the barbell can be used to observe the trajectories of our players cite the usual process cannot be observed in the presence of malfunction or habits, so that the coach can find the problem more accurately guide the players. Our system can be applied in practice and competition to increase the resilience of the lifter on the field.

Keywords: computer aided sport training, kinematic, trajectory, weightlifting

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Authors: Chang Liu, Nuria Fiol, Isabel Villaescusa, Jordi Poch

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Over the last decades, biosorption has been an alternative to costly wastewaters treatment for metal removal. Most of the literature on metal biosorption was devoted to studying of single metal ions but nowadays studies on multi-components biosorption are booming. Hexavalent chromium is usually found in mixtures with divalent metal ions in industries wastewaters. However, studies on the simultaneous removal of Cr(VI) and divalent metals are hardly found and the cooperative or competitive mechanism governing each metal ions sorption is still unclear. In this work, simultaneous sorption of Cr(VI) and Cu(II) from their binary mixtures by using sweet potato vine (SPV) was investigated. Sweet potato is one of the four major grain crops in China. Each year about 2000 tons of SPV are generated as by-products. SPV could be a low-cost biosorbent for metal ions due to its rich in cellulose and lignin. In this work, the sorption of Cr(VI) and Cu(II) from their binary mixtures solutions was studied by using SPV sorbent. Equilibrium studies were carried out in binary mixtures in which Cr(VI) and Cu(II) concentration was both varied between 0.1 mM and 0.3 mM, Cr(VI) and Cu(II) single solutions were also prepared as comparison. All the experiments were performed at pH 3±0.05 under 30±2°C for 7 days to make sure sorption achieved equilibrium. Results showed that (i) chromium was partially (10.93%-42.04%) eliminated under studied conditions through reduction and sorption of hexavalent and trivalent forms. The presence of Cu(II) exerts a synergistic effect on the overall sorption process in all the cases of the 0.1-0.3 mM binary mixtures concentration range. (ii) Cr(VI) removal by SPV is favoured by the presence of Cu(II) in solution, because more protons needed for Cr(VI) reduction are available due to Cu(II)-proton competition; however sorption of the formed Cr(III) is unfavoured as a result of the competition between Cr(III) and Cu(II) for protons and sorbent active sites. (iii) Copper was partially (9.26%-13.91%) sorbed onto SPV under studied conditions. The presence of Cr(VI) in binary mixtures also exerts a synergistic effect on the Cu(II) removal in all the cases of the 0.1-0.3 mM binary mixtures concentration range. The results of the present work indicate that sweet potato vine can be successfully employed for the simultaneously removal of Cr(VI) and Cu(II) in binary mixtures, taking advantage of the synergistic effect provoked by one of the metal ion to each other, even though the acquisition of higher removal yields has to be further investigated. Acknowledgements—This work has been financially supported by Ministry of Human Resources and Social Security of PRC (Anhui15), Education Department of Anhui Province (KJ2016A270) and Anhui Normal University (2015rcpy33, 2014bsqdjj53).

Keywords: sweet potato vine, chromium reduction, divalent metal, synergistic sorption

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Authors: Fatima M. Jadu, Asmaa A. Alzahrani, Maha A. Almutairi, Salma O. Al-Amoudi, Mawya A. Khafaji

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Introduction: Estimating the potential radiation risk for a widely used imaging technique such as cone beam CT (CBCT) is crucial. The aim of this study was to examine the effect of varying two CBCT technical factors, the voxel size (VOX) and the Field-of-View (FOV) centralization, on the radiation dose. Methodology: The head and neck slices of a RANDO® man phantom (Alderson Research Laboratories) were used with nanoDot™ OSLD dosimeters to measure the absorbed radiation dose at 25 predetermined sites. Imaging was done using the i-CAT® (Imaging Science International, Hatfield, PA, USA) CBCT unit. The VOX was changed for every three cycles of exposures from 0.2mm to 0.3mm and then 0.4mm. Then the FOV was centered on the maxilla and mandible alternatively while holding all other factors constant. Finally, the effective radiation dose was calculated for each view and voxel setting. Results: The effective radiation dose was greatest when the smallest VOX was chosen. When the FOV was centered on the maxilla, the highest radiation doses were recorded in the eyes and parotid glands. While on the mandible, the highest radiation doses were recorded in the sublingual and submandibular glands. Conclusion: Minor variations in the CBCT exposure factors significantly affect the effective radiation dose and thus the radiation risk to the patient. Therefore, extreme care must be taken when choosing these parameters especially for vulnerable patients such as children.

Keywords: CBCT, cone beam CT, effective dose, field of view, mandible, maxilla, resolution, voxel

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Authors: Arash Dara, Mahsa Mokhtari, Nafiseh Zamindar

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The aim of this study was to determine the effect of thermal resistance, temperature, voltage, and pH changes in an ohmic heating system on reducing the logarithmic number of Byssochlamys fulva species (PTCC 5062) in tomato juice water and to investigate the quantitative properties of tomato juice in the ohmic heating pasteurization system. The percentage of thermal degradation by ohmic heating was determined in tomato juice for the kinetics of Byssochlamys fulva in ohmic chamber at the temperatures of 88, 93, and 98°C, with two voltages of 30 and 40 volts and two pH levels of 3.5 and 4.5; this was done using Weibull frequency distribution model. Three different parameters (pH = 3.5, two voltages of 30 and 40, at three temperatures 88, 93, and 98) and (pH = 4.5, two voltages 30 and 40, at three temperatures 88, 93, and 98) in three replications were considered in the ohmic system. Heating time for the temperature of 88°C was 20 minutes once every 2 minutes, while for the temperature of 93°C, it was 10 minutes once every 1 minute. At the temperature of 98°C, the first time was 0.5 minutes, and for other times, sampling was done every 1 minute. In each condition, the qualitative characteristics, including acidity, Brix, and pH, were measured before and after the ohmic process in the tomato juice. This study demonstrates that the differences in pH and voltage due to different temperatures in the ohmic process can greatly affect the inactivation of Byssochlamys fulva fungus and the qualitative characteristics of the tomato juice. This is the first study using the Weibull frequency method to model the inactivation of Byssochlamys fulva in tomato juice. Variation in parameters such as temperature, voltage, and pH can prevent the presence of Byssochlamys fulva in the pasteurized juices.

Keywords: pasteurization, ohmic heating process, Byssochlamys fulva, tomato juice, heat resistance, voltage, pH

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Authors: Reza Ziaie Moayad, Azam Kouhpeyma

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In-situ testing is preferred to evaluate the liquefaction potential in cohesionless soils due to high disturbance during sampling. Although new in-situ methods with high accuracy have been developed, standard penetration test, the simplest and the oldest in-situ test, is still used due to the profusion of the recorded data. This paper reviews the Iranian standard of evaluating liquefaction potential in soils (codes 525) and compares the liquefaction assessment methods based on SPT results on cohesionless soil in this standard with the international standards. To this, methods for assessing liquefaction potential which are presented by Cetin et al. (2004), Boulanger and Idriss (2014) are compared with what is presented in standard 525. It is found that although the procedure used in Iranian standard of evaluating the potential of liquefaction has not been updated according to the new findings, it is a conservative procedure.

Keywords: cohesionless soil, liquefaction, SPT, standard 525

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Authors: Wai Keng Teng, Gek Cheng Ngoh, Rozita Yusoff, Mohamed Kheireddine Aroua

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As a by-product of the biodiesel industries, glycerol has been vastly generated which surpasses the market demand. It is imperative to develop an efficient glycerol valorization processes in minimizing the net energy requirement and intensifying the biodiesel production. In this study, base-catalyzed transesterification of glycerol with dimethyl carbonate using microwave irradiation as heating method to produce glycerol carbonate was conducted by varing grades of glycerol i.e. 70%, 86% and 99% purity that obtained from biodiesel plant. Metal oxide catalysts were used with varying operating parameters including reaction time, DMC/glycerol molar ratio, catalyst weight %, temperature and stirring speed. From the study on the effect of different operating parameters; it was found that the type of catalyst used has the most significant effect on the transesterification reaction. Admist the metal oxide catalysts examined, CaO gave the best performance. This study indicates the feasibility of producing glycerol carbonate using different grade of glycerol in both conventional thermal activation and microwave irradiation with CaO as catalyst. Microwave assisted transesterification (MAT) of glycerol into glycerol carbonate has demostrated itself as an energy efficient route by achieving 94.3% yield of GC at 65°C, 5 minutes reaction time, 1 wt% CaO and DMC/glycerol molar ratio of 2. The advantages of MAT transesterification route has made the direct utilization of bioglycerol from biodiesel production without the need of purification. This has marked a more economical and less-energy intensive glycerol carbonate synthesis route.

Keywords: base-catalyzed transesterification, glycerol, glycerol carbonate, microwave irradiation

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Authors: Hossein Arzani, Masoud Jafari Shalamzari, Z. Arzani

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This paper follows FAO model of suitability analysis. Influential factors affecting extensive grazing were determined and converted into a model. Taleghan rangelands were examined for common types of grazing animals as an example. Advantages and limitations were elicited. All range ecosystems’ components affect range suitability but due to the time and money restrictions, the most important and feasible elements were investigated. From which three sub-models including water accessibility, forage production and erosion sensitivity were considered. Suitable areas in four levels of suitability were calculated using GIS. This suitability modeling approach was adopted due to its simplicity and the minimal time that is required for transforming and analyzing the data sets. Managers could be benefited from the model to devise the measures more wisely to cope with the limitations and enhance the rangelands health and condition.

Keywords: range suitability, land-use, extensive grazing, modeling, land evaluation

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Authors: Nebi Gedik

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One of the significant and continual public health problems in the world is breast cancer. Early detection is very important to fight the disease, and mammography has been one of the most common and reliable methods to detect the disease in the early stages. However, it is a difficult task, and computer-aided diagnosis (CAD) systems are needed to assist radiologists in providing both accurate and uniform evaluation for mass in mammograms. In this study, a multiresolution statistical method to classify mammograms as normal and abnormal in digitized mammograms is used to construct a CAD system. The mammogram images are represented by wave atom transform, and this representation is made by certain groups of coefficients, independently. The CAD system is designed by calculating some statistical features using each group of coefficients. The classification is performed by using support vector machine (SVM).

Keywords: wave atom transform, statistical features, multi-resolution representation, mammogram

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Authors: Selamawit Dires, Solomon Tesfamariam, Thomas Tannert

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Modern earthquake engineering and design encompass performance-based design philosophy. The main objective in performance-based design is to achieve a system performing precisely to meet the design objectives so to reduce unintended seismic risks and associated losses. Energy-based earthquake-resistant design is one of the design methodologies that can be implemented in performance-based earthquake engineering. In energy-based design, the seismic demand is usually described as the ratio of the hysteretic to input energy. Once the hysteretic energy is known as a percentage of the input energy, it is distributed among energy-dissipating components of a structure. The hysteretic to input energy ratio is highly dependent on the inherent damping of a structural system. In numerical analysis, damping can be modeled as stiffness-proportional, mass-proportional, or a linear combination of stiffness and mass. In this study, the effect of mathematical modeling of damping on the estimation of seismic energy demands is investigated by considering elastic-perfectly-plastic single-degree-of-freedom systems representing short to long period structures. Furthermore, the seismicity of Vancouver, Canada, is used in the nonlinear time history analysis. According to the preliminary results, the input energy demand is not sensitive to the type of damping models deployed. Hence, consistent results are achieved regardless of the damping models utilized in the numerical analyses. On the other hand, the hysteretic to input energy ratios vary significantly for the different damping models.

Keywords: damping, energy-based seismic design, hysteretic energy, input energy

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Authors: Murat Toren, Mehmet Çelebi

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Reducing the weight of transformers while providing good performance, cost reduction and increased efficiency is important. Weight is one of the most significant factors in all electrical machines, and as such, many transformer design parameters are related to weight calculations. This study presents a comparison of the weight of oil type transformers and dry type transformer weight. Oil type transformers are mainly used in industry; however, dry type transformers are becoming more widespread in recent years. MATLAB is typically used for designing transformers and design parameters (rated voltages, core loss, etc.) along with design in ANSYS Maxwell. Similar to other studies, this study presented that the dry type transformer option is limited. Moreover, the commonly-used 50 kVA distribution transformers in the industry are oil type and dry type transformers are designed and considered in terms of weight. Currently, the preference for low-cost oil-type transformers would change if costs for dry-type transformer were more competitive. The aim of this study was to compare the weight of transformers, which is a substantial cost factor, and to provide an evaluation about increasing the use of dry type transformers.

Keywords: weight, optimization, oil-type transformers, dry-type transformers

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Authors: Nurlisa Uke Dessy, Dwi Septian Erwinsyah, Zuprizal

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This experiment was aimed to investigate the effect of rosella flower flour in diet on broiler chicken Performace. The materials used in this experiment were 72 broiler chickens and were divided into six treatments, those were R0 = without rosella flower flour addition, R1 = 0.5% rosella flower flour addition, R2 = 1.0% rosella flower flour addition, R3 = 1.5% rosella flower flour addition, R4 = 2.0% rosella flower flour addition, and R5 = 2.5% rosella flower flour addition. Each treatment consisted of three replications and each replication consisted of four broiler chickens. This research took 35 days to collect the data. Parameters measured were feed intake, rosella flower flour consumption, body weight gain, feed conversion and mortality. The collected data were analyzed using Completely Randomized Design (CRD) and the differences of mean were tested by Duncan’s New Multiple Range Test (DMRT). The result showed the average of feed consumption were 2154; 2154; 2034; 2154; 2034 and 2154 g/bird on broiler chicken that were feed respectively by 0.0; 0.5; 1.0; 1.5; 2.0; and 2.5% rosella flower flour level. The average consumptions of rosella flower flour respectively were 0; 10.77; 20.34; 32.31; 40.68; and 53.85 g/bird. The body weight gains were 1263.33±70.40; 1422.42±36.33; 1443.75±30.00; 1387.42± 35.30; 1411.17±29.58 and 1457.08±40.75 g/bird. Feed conversion results were 1.71±0.94; 1.51±0.37; 1.47±0.62; 1.55±0.40; 1.53±0.30 and 1.48±0.40. The conclusion of the experiment was known that using rosella flower flour until 2.5% level in diet was able to increase broiler chicken performance, and also to decrease broiler chicken feed conversion.

Keywords: feed intake, consumptions rosella flower flour, broiler chickens, body weight gain, feed conversion

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Authors: Matthew J. Zagumny

Abstract:

The current study reports an examination of the QUEST-25 (Q-Assessment of Undergraduate Epistemology and Scientific Thinking) online version for assessing the dispositional attitudes toward scientific thinking and intellectual curiosity among undergraduate students. The QUEST-25 consists of scientific thinking (SIQ-25) and intellectual curiosity (ICIQ-25), which were correlated in hypothesized directions with the Religious Commitment Inventory, Curiosity and Exploration Inventory, Belief in Science scale, and measures of academic self-efficacy. Additionally, concurrent validity was established by the resulting significant differences between those identifying the centrality of religious belief in their lives and those who do not self-identify as being guided daily by religious beliefs. This study demonstrates the utility of the QUEST-25 for research, evaluation, and theory development.

Keywords: guided-inquiry learning, intellectual curiosity, psychometric assessment, scientific thinking

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Authors: Bet El Silisna Lagarense, Agustinus Walansendow

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Manado Waterfront Development (MWD) occurs along the coastline of the city to meet the communities’ various needs and interests. Manado waterfront, with its various kinds of tourist attractions, is being developed to strengthen opportunities for both tourism and other businesses. There are many buildings that are used for trade and business purposes. The spatial distributions of tourism, commercial and residential land uses overlap. Field research at the study site consisted desktop scan, questionnaire-based survey, observation and in-depth interview with key informants and Focus Group Discussion (FGD) identified how MWD was initially planned and designed in the whole process of decision making in terms of resource and environmental management particularly for the waterfront tourism development in the long run. The study developed a clustered-based model for waterfront urban tourism in Manado through evaluation of spatial distribution of tourism uses along the waterfront.

Keywords: clustered-based model, Manado, urban tourism, waterfront

Procedia PDF Downloads 286

Authors: Hadi Rad

Abstract:

Unrestricted somatic stem cells (USSCs) loaded in nanofibrous PHBV scaffold can be used for skin regeneration when grafted into full-thickness skin defects of rats. Nanofibrous PHBV scaffolds were designed using electrospinning method and then, modified with the immobilized collagen via the plasma method. Afterward, the scaffolds were evaluated using scanning electron microscopy, physical and mechanical assays. In this study; nanofibrous PHBV scaffolds loaded with and without USSCs were grafted into the skin defects. The wounds were subsequently investigated at 21 days after grafting. Results of mechanical and physical analyses showed good resilience and compliance to movement as a skin graft. In animal models; all study groups excluding the control group exhibited the most pronounced effect on wound closure, with the statistically significant improvement in wound healing being seen on post-operative Day 21. Histological and immunostaining examinations of healed wounds from all groups, especially the groups treated with stem cells, showed a thin epidermis plus recovered skin appendages in the dermal layer. Thus, the graft of collagen-coated nanofibrous PHBV scaffold loaded with USSC showed better results during the healing process of skin defects in rat model.

Keywords: collagen, nanofibrous PHBV scaffold, unrestricted somatic stem cells, wound healing.

Procedia PDF Downloads 349

Authors: Hatem Radwan Ibrahim Radwan

Abstract:

Leadership is crucial for hotel survival and success. It enables hotels to develop and compete effectively. This research intends to explore the implementation of six leadership styles by frontline hotel managers in four star hotels in Cairo and assess its impact on employees’ creativity and organizational commitment. The leadership patterns considered in this study includes: democratic, autocratic, laissez-faire, transformational, transactional, and ethical leaderships. Questionnaire was used as a research method to gather data. A structured survey was established and distributed on employees in Cairo’s four star hotels. A total of 284 questionnaire forms were returned and usable for statistical analysis. The results of this study identified that transactional and autocratic leadership were the prevalent styles used in four star hotels in Cairo. Two leadership styles proved to have significant high correlation and impact on employees’ creativity and organizational commitment including: transformational and democratic leadership. Besides, laissez-faire leadership was found had a smaller effect on employees’ creativity and ethical leadership had a lesser influence on employees’ commitment. The autocratic leadership had strong negative correlation and significant impact on both dependent variables. This research concludes that frontline hotel managers should adopt transformational and/or democratic leadership style in managing their subordinates.

Keywords: creativity, hotels, leadership styles, organizational commitment

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Authors: Mlk. Khouadjia, B. Mezghiche

Abstract:

The environment protection has led to a growing interest in the use of crushed sand, which is not correctly exploited due to the high rate of fine particles that it contains and which affect concrete properties. This study will examine the variation of the compressive strength of concrete with several local areas of sand exposed to freeze-thaw cycles and chemical solutions. The experiments have been realized on crushed, river, and dune sands. We use software (MATLAB) to find the coefficient of particle shape. Finally, we have found a relationship between the reference concrete without modification and concrete modified with river and dune sands to predict the variations of resistance after curing in different environments. The results showed that the behavior of concrete is different according to the types of sand and the environment of exposition.

Keywords: crushed sand, compressive strength, freeze-thaw, MATLAB, dune sand, river sand

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Authors: Supriya Patibanda, Xiaopeng Gong, Krishna N. Jonnalagadda, Ralph Abrahams

Abstract:

Yttria stabilized zirconia (YSZ) is used as a top coat in thermal barrier coatings in high-temperature turbine/jet engine applications. The mechanical behaviour of YSZ depends on the microstructural features like crack density and porosity, which are a result of coating method. However, experimentally ascertaining their individual effect is difficult due to the inherent challenges involved like material synthesis and handling. The current work deals with the development of a phenomenological model to replicate the tensile behavior of air plasma sprayed YSZ obtained from experiments. Initially, uniaxial tensile experiments were performed on freestanding YSZ coatings of ~300 µm thick for different crack densities and porosities. The coatings exhibited a nonlinear behavior and also a huge variation in strength values. With the obtained experimental tensile curve as a base and crack density and porosity as prime variables, a phenomenological model was developed using ABAQUS interface with new user material defined employing VUMAT sub routine. The relation between the tensile stress and the crack density was empirically established. Further, a parametric study was carried out to investigate the effect of the individual features on the non-linearity in these coatings. This work enables to generate new coating designs by varying the key parameters and predicting the mechanical properties with the help of a simulation, thereby minimizing experiments.

Keywords: crack density, finite element method, plasma sprayed coatings, VUMAT

Procedia PDF Downloads 135

Authors: Hussein Abbas Jebur, Yasir Abd Ulrazzaq

Abstract:

This study was carried out at the farm of El-Gemmaiza Agriculture Research Station, El-Garbia Governorate Egypt, to determine the performance characteristics of an agricultural transport. The performance of this transportation was compared between three surfaces (asphalt, dusty and field). The study was concentrated on the rate of drawbar pull, slip ratio, tractive efficiency and specific energy per unit area. The comparison was made under three different surfaces (asphalt, dusty and field), different traveling speeds from (3.38 to 6.55 km/h) and variable weights (0 and 300 kg). The results showed that the highest value of the tractive efficiency 60.20% was obtained at traveling speed 4.00 km/h with weight on the rear wheel on the asphalt surface. The highest value of specific energy 1.93 kW.h/ton during use of ballast on rear tractor wheels at traveling speed 3.38 km/h on the field surface.

Keywords: tractor, energy, transportation, weight, power

Procedia PDF Downloads 273