Search results for: oblique angle

Authors: Gongbing Shan, Shiming Li, Zhao Zhang, Bingjun Wan

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Badminton originated in ancient civilizations in Europe and Asia more than 2000 years ago. Presently, it is played almost everywhere with estimated 220 million people playing badminton regularly, ranging from professionals to recreational players; and it is the second most played sport in the world after soccer. In Asia, the popularity of badminton and involvement of people surpass soccer. Unfortunately, scientific researches on badminton skills are hardly proportional to badminton’s popularity. A search of literature has shown that the literature body of biomechanical investigations is relatively small. One of the dominant skills in badminton is the forehand overhead smash, which consists of 1/5 attacks during games. Empirical evidences show that one has to adjust the body position in relation to the coming shuttlecock to produce a powerful and accurate smash. Therefore, positioning is a fundamental aspect influencing smash quality. A search of literature has shown that there is a dearth/lack of study on this fundamental aspect. The goals of this study were to determine the influence of positioning and training experience on smash quality in order to discover information that could help learn/acquire the skill. Using a 10-camera, 3D motion capture system (VICON MX, 200 frames/s) and 15-segment, full-body biomechanical model, 14 skilled and 15 novice players were measured and analyzed. Results have revealed that the body positioning has direct influence on the quality of a smash, especially on shuttlecock release angle and clearance height (passing over the net) of offensive players. The results also suggest that, for training a proper positioning, one could conduct a self-selected comfort position towards a statically hanged shuttlecock and then step one foot back – a practical reference marker for learning. This perceptional marker could be applied in guiding the learning and training of beginners. As one gains experience through repetitive training, improved limbs’ coordination would increase smash quality further. The researchers hope that the findings will benefit practitioners for developing effective training programs for beginners.

Keywords: 3D motion analysis, biomechanical modeling, shuttlecock release speed, shuttlecock release angle, clearance height

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Authors: Yuanrui Xu, Zailin Yang, Yunqiu Song, Guanxixi Jiang

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It is an important subject of seismology on the influence of local topography on ground motion during earthquake. In mountainous areas with complex terrain, the construction of the tunnel is often the most effective transportation scheme. In these projects, the local terrain can be simplified into hills with different shapes, and the underground tunnel structure can be regarded as a subsurface cavity. The presence of the subsurface cavity affects the strength of the rock mass and changes the deformation and failure characteristics. Moreover, the scattering of the elastic waves by underground structures usually interacts with local terrains, which leads to a significant influence on the surface displacement of the terrains. Therefore, it is of great practical significance to study the surface displacement of local terrains with underground tunnels in earthquake engineering and seismology. In this work, the region is divided into three regions by the method of region matching. By using the fractional Bessel function and Hankel function, the complex function method, and the wave function expansion method, the wavefield expression of SH waves is introduced. With the help of a constitutive relation between the displacement and the stress components, the hoop stress and radial stress is obtained subsequently. Then, utilizing the continuous condition at different region boundaries, the undetermined coefficients in wave fields are solved by the Fourier series expansion and truncation of the finite term. Finally, the validity of the method is verified, and the surface displacement amplitude is calculated. The surface displacement amplitude curve is discussed in the numerical results. The results show that different parameters, such as radius and buried depth of the tunnel, wave number, and incident angle of the SH wave, have a significant influence on the amplitude of surface displacement. For the underground tunnel, the increase of buried depth will make the response of surface displacement amplitude increases at first and then decreases. However, the increase of radius leads the response of surface displacement amplitude to appear an opposite phenomenon. The increase of SH wave number can enlarge the amplitude of surface displacement, and the change of incident angle can obviously affect the amplitude fluctuation.

Keywords: method of region matching, scattering of SH wave, subsurface cavity, trapezoidal hill

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Authors: Amaraja Taur, Pankaj Doshi, Hak Koon Yeoh

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The dripping modes for a Newtonian liquid of viscosity µ emanating from an inclined nozzle at flow rate Q is investigated experimentally. As the liquid flow rate Q increases, starting with period-1 with satellite drops, the system transitions to period-1 dripping without satellite, then to limit cycle before showing chaotic responses. Phase diagrams shows the changes in the transitions between the different dripping modes for different nozzle inclination angle θ is constructed in the dimensionless (Q, µ) space.

Keywords: dripping, inclined nozzle, phase diagram, satellite

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Authors: A. Bhandari, S. Mukherjee

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Two frames in a Hilbert space are called woven or weaving if all possible merge combinations between them generate frames of the Hilbert space with uniform frame bounds. Weaving frames are powerful tools in wireless sensor networks which require distributed data processing. Considering the practical applications, this article deals with finite woven frames. We provide methods of constructing finite woven frames, in particular, bounded linear operators are used to construct woven frames from a given frame. Several examples are discussed. We also introduce the notion of woven frame sequences and characterize them through the concepts of gaps and angles between spaces.

Keywords: frames, woven frames, gap, angle

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Authors: Edith Podhovnik

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Cultures play a role in business communication and in research. At the example of language in international business, this paper addresses the issue of how the research cultures of management research and linguistics as well as cultures as such can be linked. After looking at existing research on language in international business, this paper approaches communication in international business from a linguistic angle and attempts to explain communication issues in businesses based on linguistic research. Thus, the paper makes a step into cross-disciplinary research combining management research with linguistics.

Keywords: language in international business, sociolinguistics, ethnopragmatics, cultural scripts

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Authors: Viktor Kochkodan

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The main problem arising upon water treatment and desalination using pressure driven membrane processes such as microfiltration, ultrafiltration, nanofiltration and reverse osmosis is membrane fouling that seriously hampers the application of the membrane technologies. One of the main approaches to mitigate membrane fouling is to minimize adhesion interactions between a foulant and a membrane and the surface coating of the membranes with polyelectrolytes seems to be a simple and flexible technique to improve the membrane fouling resistance. In this study composite polyamide membranes NF-90, NF-270, and BW-30 were modified using electrostatic deposition of polyelectrolyte multilayers made from various polycationic and polyanionic polymers of different molecular weights. Different anionic polyelectrolytes such as: poly(sodium 4-styrene sulfonate), poly(vinyl sulfonic acid, sodium salt), poly(4-styrene sulfonic acid-co-maleic acid) sodium salt, poly(acrylic acid) sodium salt (PA) and cationic polyelectrolytes such as poly(diallyldimethylammonium chloride), poly(ethylenimine) and poly(hexamethylene biguanide were used for membrane modification. An effect of deposition time and a number of polyelectrolyte layers on the membrane modification has been evaluated. It was found that degree of membrane modification depends on chemical nature and molecular weight of polyelectrolytes used. The surface morphology of the prepared composite membranes was studied using atomic force microscopy. It was shown that the surface membrane roughness decreases significantly as a number of the polyelectrolyte layers on the membrane surface increases. This smoothening of the membrane surface might contribute to the reduction of membrane fouling as lower roughness most often associated with a decrease in surface fouling. Zeta potentials and water contact angles on the membrane surface before and after modification have also been evaluated to provide addition information regarding membrane fouling issues. It was shown that the surface charge of the membranes modified with polyelectrolytes could be switched between positive and negative after coating with a cationic or an anionic polyelectrolyte. On the other hand, the water contact angle was strongly affected when the outermost polyelectrolyte layer was changed. Finally, a distinct difference in the performance of the noncoated membranes and the polyelectrolyte modified membranes was found during treatment of seawater in the non-continuous regime. A possible mechanism of the higher fouling resistance of the modified membranes has been discussed.

Keywords: contact angle, membrane fouling, polyelectrolytes, surface modification

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Authors: Laura A. Rodriguez-Villamizar, Alvaro Osornio-Vargas, Brian H. Rowe, Rhonda J. Rosychuk

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Introduction/Objectives: The Census Metropolitan Area of Edmonton (CMAE) has important industrial emissions to the air from the Industrial Heartland Alberta (IHA) at the Northeast and the coal-fired power plants (CFPP) at the West. The objective of the study was to explore the presence of clusters of children asthma ED visits in the areas around the IHA and the CFPP. Methods: Retrospective data on children asthma ED visits was collected at the dissemination area (DA) level for children between 2 and 14 years of age, living in the CMAE between April 1, 2004, and March 31, 2010. We conducted a spatial analysis of disease clusters around putative sources with count (ecological) data using descriptive, hypothesis testing, and multivariable modeling analysis. Results: The mean crude rate of asthma ED visits was 9.3/1,000 children population per year during the study period. Circular spatial scan test for cases and events identified a cluster of children asthma ED visits in the DA where the CFPP are located in the Wabamum area. No clusters were identified around the IHA area. The multivariable models suggest that there is a significant decline in risk for children asthma ED visits as distance increases around the CFPP area this effect is modified at the SE direction with mean angle 125.58 degrees, where the risk increases with distance. In contrast, the regression models for IHA suggest that there is a significant increase in risk for children asthma ED visits as distance increases around the IHA area and this effect is modified at SW direction with mean angle 216.52 degrees, where the risk increases at shorter distances. Conclusions: Different methods for detecting clusters of disease consistently suggested the existence of a cluster of children asthma ED visits around the CFPP but not around the IHA within the CMAE. These results are probably explained by the direction of the air pollutants dispersion caused by the predominant and subdominant wind direction at each point. The use of different approaches to detect clusters of disease is valuable to have a better understanding of the presence, shape, direction and size of clusters of disease around pollution sources.

Keywords: air pollution, asthma, disease cluster, industry

Procedia PDF Downloads 267

Authors: Mauricio A. Sarabia-Vallejos, Carmen M. Gonzalez-Henriquez, Adolfo Del Campo-Garcia, Aitzibier L. Cortajarena, Juan Rodriguez-Hernandez

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In this study, it was explored the formation and the morphological differences between wrinkled hydrogel patterns obtained via generation of surface instabilities. The slight variations in the polymerization conditions produce important changes in the material composition and pattern structuration. The compounds were synthesized using three main components, i.e. an amphiphilic monomer, hydroxyethyl methacrylate (HEMA), a hydrophobic monomer, trifluoroethyl methacrylate (TFMA), and a hydrophilic crosslinking agent, poly(ethylene glycol) diacrylate (PEGDA). The first part of this study was related to the formation of wrinkled surfaces using only HEMA and PEGDA and varying the amount of water added in the reaction. The second part of this study involves the gradual insertion of TFMA into the hydrophilic reaction mixture. Interestingly, the manipulation of the chemical composition of this hydrogel affects both surface morphology and physicochemical characteristics of the patterns, inducing transitions from one particular type of structure (wrinkles or ripples) to different ones (creases, folds, and crumples). Contact angle measurements show that the insertion of TFMA produces a slight decrease in surface wettability of the samples, remaining however highly hydrophilic (contact angle below 45°). More interestingly, by using confocal Raman spectroscopy, important information about the wrinkle formation mechanism is obtained. The procedure involving two consecutive thermal and photopolymerization steps lead to a “pseudo” two-layer system. Thus, upon photopolymerization, the surface is crosslinked to a higher extent than the bulk and water evaporation drives the formation of wrinkled surfaces. Finally, cellular, and bacterial proliferation studies were performed to the samples, showing that the amount of TFMA included in each sample slightly affects the proliferation of both (bacteria and cells), but in the case of bacteria, the morphology of the sample also plays an important role, importantly reducing the bacterial proliferation.

Keywords: antibiofouling properties, hydrophobic/hydrophilic balance, morphologic characterization, wrinkled hydrogel patterns

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Authors: Himalaya Patir, Bitupon Baruah, Sanjay Gayary, Subhajit Ray

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In recent age significant importance is given for the development of nutritious and health beneficial foods. Fruit juices collected from different fruits when blended that improves not only the physicochemical and nutritional properties but also enhance the sensorial or organoleptic properties. The study was carried out to determine the physico-chemical, nutritional, microbiological analysis and sensory evaluation of mixed fruit juice blend. Juice of orange (Citrus sinensis), apple (Malus domestica), mosambi (Citrus limetta) were blended in the ratio of sample-I (30% apple:30% orange:40% mosambi), sample-II ( 40% apple :30% orange :30% mosambi), sample-III (30% apple :40% orange :30% mosambi) , sample-IV (50% apple :30% orange :20% mosambi), sample-V (30% apple:20% orange:50% mosambi), sample-VI (20% apple :50% orange :30% mosambi) to evaluate all quality characteristics. Their colour characteristics in terms of hue angle, chroma and colour difference (∆E) were evaluated. The physico-chemical parameters analysis carried out were total soluble solids (TSS), total titratable acidity (TTA), pH, acidity (FA), volatile acidity (VA), pH, and vitamin C. There were significant differences (p˂0.05) in the TSS of the samples. However, sample-V (30% apple: 20% orange: 50% mosambi) provides the highest TSS of 9.02gm and significantly differed from other samples (p˂0.05). Sample-IV (50% apple: 30% orange: 20% mosambi) was shown the highest titratable acidity (.59%) in comparison to other samples. The highest value of pH was found as 5.01 for sample-IV (50% apple: 30% orange: 20% mosambi). Sample-VI (20% apple: 50% orange :30% mosambi) blend has the highest hue angle, chroma and colour changes of 72.14,25.29 and 54.48 and vitamin C, i.e. Ascorbic acid (.33g/l) content compared to other samples. The nutritional compositions study showed that, sample- VI (20% apple: 50% orange: 30% mosambi) has the significantly higher carbohydrate (51.67%), protein (.78%) and ash (1.24%) than other samples, while sample-V (30% apple: 20% orange: 50% mosambi) has higher dietary fibre (12.84%) and fat (2.82%) content. Microbiological analysis of all samples in terms of total plate count (TPC) ranges from 44-60 in 101 dilution and 4-5 in 107 dilutions and was found satisfactory. Moreover, other pathogenic bacterial count was found nil. The general acceptability of the mixed fruit juice blend samples were moderately liked by the panellists, and sensorial quality studies showed that sample-V (30% apple: 20% orange: 50% mosambi) contains highest overall acceptability of 8.37 over other samples and can be considered good for consumption.

Keywords: microbiological, nutritional, physico-chemical, sensory properties

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Authors: Emigdio Mendoza, Patricia Fernandez, Cristian Gomez

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Magnesium alloys have generated great interest for several industrial applications because their high specific strength and low density make them a very attractive alternative for the manufacture of various components; however, these alloys present a limitation with their hexagonal crystal structure that limits the deformation mechanisms at room temperature likewise the molding components alternatives, it is for this reason that severe plastic deformation processes have taken a huge relevance recently because these, allow high deformation rates to be applied that induce microstructural changes where the deficiency in the sliding systems is compensated with crystallographic grains reorientations or crystal twinning. The present study reports a statistical analysis of process temperature, number of passes and shear angle with respect to the shear stress in severe plastic deformation process denominated 'Equal Channel Angular Sheet Drawing (ECASD)' applied to the magnesium alloy AZ31B through Python Statsmodels libraries, additionally a Post-Hoc range test is performed using the Tukey statistical test. Statistical results show that each variable has a p-value lower than 0.05, which allows comparing the average values of shear stresses obtained, which are in the range of 7.37 MPa to 12.23 MPa, lower values in comparison to others severe plastic deformation processes reported in the literature, considering a value of 157.53 MPa as the average creep stress for AZ31B alloy. However, a higher stress level is required when the sheets are processed using a shear angle of 150°, due to a higher level of adjustment applied for the shear die of 150°. Temperature and shear passes are important variables as well, but there is no significant impact on the level of stress applied during the ECASD process. In the processing of AZ31B magnesium alloy sheets, ECASD technique is evidenced as a viable alternative in the modification of the elasto-plastic properties of this alloy, promoting the weakening of the basal texture, which means, a better response to deformation, whereby, during the manufacture of parts by drawing or stamping processes the formation of cracks on the surface can be reduced, presenting an adequate mechanical performance.

Keywords: plastic deformation, strain, sheet drawing, magnesium

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Authors: E. Kaygan, A. Gatto

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An investigation of adaptable winglets for morphing aircraft control and performance is described in this paper. The concepts investigated consist of various winglet configurations fundamentally centred on a baseline swept wing. The impetus for the work was to identify and optimize winglets to enhance controllability and the aerodynamic efficiency of a small unmanned aerial vehicle. All computations were performed with Athena Vortex Lattice modelling with varying degrees of twist, swept, and dihedral angle considered. The results from this work indicate that if adaptable winglets were employed on small scale UAV’s improvements in both aircraft control and performance could be achieved.

Keywords: aircraft, rolling, wing, winglet

Procedia PDF Downloads 444

Authors: Muhammad Naveed Ali, Hamad Bin Rashid, Muhammad Arif Khan, Abdul Basit, Hafiz Muhammad Arshad

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Abdominal defects are very common in pigeons. A new technique is known as intraabdominal mesh transplant that give better protection for herniorrhaphy. The aim of this study was to determine the performance of hernia mesh. In this study, an efficacy of two synthetic hernia mesh implants viz. conventional Prolene and a lightweight mesh monofilament polyester were assessed for the abdominal wall repair in pigeons. Twenty four healthy pigeons were selected and randomly distributed into three groups, A, B and C (n=8). In all groups, experimental laparotomy was performed; thereafter, abdominal muscles and peritoneum were sutured together, while, a 2 x 2 cm defect was created in the abdominal muscles. For onlay hernioplasty, the hernia mesh (Prolene mesh: group A; Polyester mesh: group B) was implanted over the external oblique muscles of the abdomen. In group C (control), the mesh was not implanted; instead, the laparotomy incision was closed after a herniorrhaphy. Post-operative pain wound healing, adhesion formation, histopathological findings and formation of hematoma, abscess and seroma were assessed as short-term complications. Post-operatively, pain at surgical site was significantly less (P < 0.001) in group B (Polyester mesh); wound healing was also significantly better and rapid in group B (P < 0.05) than in group A (Prolene mesh). Group B (Polyester mesh) also depicted less than 25% adhesions when assessed on the basis of a Quantitative Modified Diamond scale; a Qualitative Adhesion Tenacity scale also depicted either no adhesions or flimsy adhesions (n=2) in group B (Polyester mesh), in contrast to group A (Prolene), which manifested greater adhesion formation and presence of dense adhesions requiring blunt dissection. There were observed hematoma, seroma and abscess formations in birds treated by Prolene mesh only. Conclusively, the polyester mesh proved superior to the Prolene mesh regarding lesser adhesion, better in wound healing, and no short-term follow-up complications.

Keywords: adhesion, mesh, polyester, prolene

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Authors: Mehdi Homayouni, Karim Adinehvand, Bakhtiar Azadbakht

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In this study, we used Monte Carlo code (MCNP4C) that is a general method, for simulation, electron source and electric field, a disc source with 0.05 cm radius in direct of anode are used, radius of disc source show focal spot of X-ray tube that here is 0.05 cm. In this simulation, the anode is from tungsten with 18.9 g/cm3 density and angle of the anode is 18°. We simulated X-ray tube for 140 kv. For increasing of speed data acquisition, we use F5 tally. With determination the exact position of F5 tally in the program, outputs are acquired. In this spectrum the start point is about 0.02 Mev, the absorption edges are about 0.06 Mev and 0.07 Mev, and average energy is about 0.05 Mev.

Keywords: X-spectrum, simulation, Monte Carlo, tube

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Authors: Chalise Kiran

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The learning difficulties of children with disabilities are always a matter of concern when we talk about educational needs and quality education of children with disabilities. This paper is the outcome of the review of the literatures based on the literatures on the educational needs and learning difficulties of children with disabilities. For the paper, different studies written on children with disabilities and their education were collected through search engines. The literature put together was analyzed from the angle of learning difficulties faced by children with disabilities and the same were used as a precursor to arrive at the findings on the learning of the children. The analysis showed that children with disabilities face learning difficulties. The reasons for these difficulties could be attributed to factors in terms of authority, structure, school environment, and behaviors of teachers and parents, and the society as a whole.

Keywords: children with disabilities, learning difficulties, education, disabled children

Procedia PDF Downloads 95

Authors: Amin Sahebnasagh, Karim Adinehvand, Bakhtiar Azadbakht

Abstract:

In this study, we used Monte Carlo code (MCNP4C) that is a general method, for simulation, electron source and electric field, a disc source with 0.05 cm radius in direct of anode are used, radius of disc source show focal spot of x-ray tube that here is 0.05 cm. In this simulation, anode is from tungsten with 18.9 g/cm3 density and angle of anode is 180. we simulated x-ray tube for 140 kv. For increasing of speed data acquisition we use F5 tally. With determination the exact position of F5 tally in program, outputs are acquired. In this spectrum the start point is about 0.02 Mev, the absorption edges are about 0.06 Mev and 0.07 Mev and average energy is about 0.05 Mev.

Keywords: x-spectrum, simulation, Monte Carlo, MCNP4C code

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Authors: Y. Galerkin, L. Marenina

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Stator elements «Vane diffuser + crossover + return channel» of stages with different specific speed were investigated by CFD calculations. The regime parameter was introduced to present efficiency and loss coefficient performance of all elements together. Flow structure demonstrated advantages and disadvantages of design. Flow separation in crossovers was eliminated by its shape modification. Efficiency increased visibly. Calculated CFD performances are in acceptable correlation with predicted ones by engineering design method. The information obtained is useful for design method better calibration.

Keywords: vane diffuser, return channel, crossover, efficiency, loss coefficient, inlet flow angle

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Authors: Himani Sharma, Amit Agrawal

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Stability of the Cassie and Wenzel wetting states depends on intrinsic contact angle and geometric features on a surface that was exploited in capturing biofluids in microwells. However, the mechanism of imbibition of biofluids in the microwells is not well implied in terms of wettability of a substrate. In this work, we experimentally demonstrated filling dynamics in hydrophilic and hydrophobic microwells by protein solutions. Towards this, we utilized lotus leaf as a mold to fabricate microwells on a Polydimethylsiloxane (PDMS) surface. Lotus leaf containing micrometer-sized blunt-conical shaped pillars with a height of 8-15 µm and diameter of 3-8 µm were transferred on to PDMS. Furthermore, PDMS surface was treated with oxygen plasma to render the hydrophilic nature. A 10µL droplets containing fluorescein isothiocyanate (FITC) - labelled bovine serum albumin (BSA) were rested on both hydrophobic (θa = 108o, where θa is the apparent contact angle) and hydrophilic (θa = 60o) PDMS surfaces. A time-dependent fluorescence microscopy was conducted on these modified PDMS surfaces by recording the fluorescent intensity over a 5 minute period. It was observed that, initially (at t=1 min) FITC-BSA was accumulated on the periphery of both hydrophilic and hydrophobic microwells due to incomplete penetration of liquid-gas meniscus. This deposition of FITC-BSA on periphery of microwell was not changed with time for hydrophobic surfaces, whereas, a complete filling was occurred in hydrophilic microwells (at t=5 mins). This attributes to a gradual movement of three-phase contact line along the vertical surface of the hydrophilic microwells as compared to stable pinning in the hydrophobic microwells as confirmed by Surface Evolver simulations. In addition, if the cavities are presented on hydrophobic surfaces, air bubbles will be trapped inside the cavities once the aqueous solution is placed over these surfaces, resulting in the Cassie-Baxter wetting state. This condition hinders trapping of proteins inside the microwells. Thus, it is necessary to impart hydrophilicity to the microwell surfaces so as to induce the Wenzel state, such that, an entire solution will be fully in contact with the walls of microwells. Imbibition of microwells by protein solutions was analyzed in terms fluorescent intensity versus time. The present work underlines the importance of geometry of microwells and surface wettability of substrate in wetting and effective capturing of solid sub-phases in biofluids.

Keywords: BSA, microwells, surface evolver, wettability

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Authors: A. Mostaani, M. P. Pereira, B. F. Rolfe

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The increasing application of Advanced High Strength Steel (AHSS) in the automotive industry to fulfill crash requirements has introduced higher levels of wear in stamping dies and parts. Therefore, understanding wear behaviour in sheet metal forming is of great importance as it can help to reduce the high costs currently associated with tool wear. At the contact between the die and the sheet, the tips of hard tool asperities interact with the softer sheet material. Understanding the deformation that occurs during this interaction is important for our overall understanding of the wear mechanisms. For these reasons, the scratching of a perfectly plastic material by a rigid indenter has been widely examined in the literature; with finite element modelling (FEM) used in recent years to further understand the behaviour. The ‘wear mode diagram’ has been commonly used to classify the deformation regime of the soft work-piece during scratching, into three modes: ploughing, wedge formation, and cutting. This diagram, which is based on 2D slip line theory and upper bound method for perfectly plastic work-piece and rigid indenter, relates different wear modes to attack angle and interfacial strength. This diagram has been the basis for many wear studies and wear models to date. Additionally, it has been concluded that galling is most likely to occur during the wedge formation mode. However, there has been little analysis in the literature of how the material behaviour and deformation conditions associated with metal forming processes influence the wear behaviour. Therefore, the first aim of this work is first to use a commercial FEM package (Abaqus/Explicit) to build a 3D model to capture wear modes during scratching with indenters with different attack angles and different interfacial strengths. The second goal is to utilise the developed model to understand how wear modes might change in the presence of bulk deformation of the work-piece material as a result of the metal forming operation. Finally, the effect of the work-piece material properties, including strain hardening, will be examined to understand how these influence the wear modes and wear behaviour. The results show that both strain hardening and substrate deformation can change the critical attack angle at which the wedge formation regime is activated.

Keywords: finite element, pile-up, scratch test, wear mode

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Authors: Mirjana Ilic, Dragan Zivotic, Aleksandra Perovic, Predrag Gavrilovic

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The service quality perception depends on many factors, such as the area in which the services are provided, socioeconomic status, educational status, experience, age and gender of consumers, as well as many others. For this reason, it is not possible to apply instrument for establishing the service quality perception that is developed in other areas and in other populations. The aim of the research was to form an instrument for assessing the quality perception in the field of fitness in Serbia. After analyzing the available literature and conducting a pilot research, there were 15 isolated areas in which it was possible to observe the service quality perception. The areas included: material and technical basis, secondary facilities, coaches, programs, reliability, credibility, security, rapid response, compassion, communication, prices, satisfaction, loyalty, quality outcomes and motives. These areas were covered by a questionnaire consisted of 100 items where the number of items varied from area to area from 3 up to 11. The questionnaire was administered to 350 subjects of both genders (174 men and 176 women) aged from 18 to 68 years, being beneficiaries of fitness services for at least 1 year. In each of the areas was conducted a factor analysis in its exploratory form by principal components method. The number of significant factors has been determined in accordance with the Kaiser Guttman criterion. The initial factor solutions were simplified using the Varimax rotation. Analyses per areas have produced from 1 to 4 factors. Afterward, the factor analysis of factor scores on the first principal component of each of the respondents in each of the analyzed area was performed, and the factor structure was obtained with four latent dimensions interpreted as offer, the relationship with the coaches, the experience of quality and the initial impression. This factor structure was analysed by hierarchical analysis of Oblique factors, which in the second order space produced single factor interpreted as a general factor of the service quality perception. The resulting questionnaire represents an instrument which can serve managers in the field of fitness to optimize the centers development, raising the quality of services in line with consumers needs and expectations.

Keywords: fitness, hierarchical model, quality perception, factor analysis

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Authors: Abdi Ismail, Zain Amarta, Riza Rifaldy Argaputra

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The Helical Turbine has the highest efficiency in comparison with the other hydrokinetic turbines. However, the potential of the Helical Turbine efficiency can be further improved so that the kinetic energy of a water current can be converted into mechanical energy as much as possible. This paper explains the effects by adding a Movable Airfoil Arm (MAA) and ducting on a Helical Turbine. The first research conducted an analysis of the efficiency comparison between a Plate Arm Helical Turbine (PAHT) versus a Movable Arm Helical Turbine Airfoil (MAAHT) at various water current velocities. The first step is manufacturing a PAHT and MAAHT. The PAHT and MAAHT has these specifications (as a fixed variable): 80 cm in diameter, a height of 88 cm, 3 blades, NACA 0018 blade profile, a 10 cm blade chord and a 60o inclination angle. The MAAHT uses a NACA 0012 airfoil arm that can move downward 20o, the PAHT uses a 5 mm plate arm. At the current velocity of 0.8, 0.85 and 0.9 m/s, the PAHT respectively generates a mechanical power of 92, 117 and 91 watts (a consecutive efficiency of 16%, 17% and 11%). At the same current velocity variation, the MAAHT respectively generates 74, 60 and 43 watts (a consecutive efficiency of 13%, 9% and 5%). Therefore, PAHT has a better performance than the MAAHT. Using analysis from CFD (Computational Fluid Dynamics), the drag force of MAA is greater than the one generated by the plate arm. By using CFD analysis, the drag force that occurs on the MAA is more dominant than the lift force, therefore the MAA can be called a drag device, whereas the lift force that occurs on the helical blade is more dominant than the drag force, therefore it can be called a lift device. Thus, the lift device cannot be combined with the drag device, because the drag device will become a hindrance to the lift device rotation. The second research conducted an analysis of the efficiency comparison between a Ducted Helical Turbine (DHT) versus a Helical Turbine (HT) through experimental studies. The first step is manufacturing the DHT and HT. The Helical turbine specifications (as a fixed variable) are: 40 cm in diameter, a height of 88 cm, 3 blades, NACA 0018 blade profile, 10 cm blade chord and a 60o inclination angle. At the current speed of 0.7, 0.8, 0.9 and 1.1 m/s, the HT respectively generates a mechanical power of 72, 85, 93 and 98 watts (a consecutive efficiency of 38%, 30%, 23% and 13%). At the same current speed variation, the DHT generates a mechanical power of 82, 98, 110 and 134 watts (a consecutive efficiency of 43%, 34%, 27% and 18%), respectively. The usage of ducting causes the water current speed around the turbine to increase.

Keywords: hydrokinetic turbine, helical turbine, movable airfoil arm, ducting

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Authors: Lopez J., Mehrvar M., Quinones E., Suarez A., RomeroC.

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The Silver Nanoparticles (AgNP) are used as deliver of heat on surface of Membrane Distillation in order to fight against Thermal Polarization and improving the Desalination Process. In this study AgNPwere deposited by dip coating process over PVDF, FG hydrophilic, and PTFE hydrophobic commercial membranes as substrate. Membranes were characterized by SEM, EDS, contact angle, Pore size distributionand using a UV lamp and a thermal camera were measured the performance of heat deliver. The presence of AgNP 50 – 150 nm and the increase in absorption of energy over membrane were verified.

Keywords: silver nanoparticles, membrane distillation, plasmon effect, heat deliver

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Authors: L. P. L. Nguyen, G. Hitka, T. Zsom, Z. Kókai

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This study is aimed to investigate the influence of postharvest delays of 1-Methylcyclopropene (1-MCP) treatment on prolonging the storage potential of melon. Melons were treated with 625-650 ppb 1-MCP at 10 °C for 24 hours on the 1st, 3rd and 5th day after harvest. Decreased ethylene production and retarded softening of melon fruits after 7 days of storage at 10 °C plus 3 days of shelflife were obtained by 1-MCP applications. 1-MCP strongly affected the chlorophyll fluorescence characteristics and hue angle values of melon. After shelf-life, the peel color of treated melon was slow in turning to yellow compared to the control. Additionally, firmness of melons treated on the first day after harvest was 38% higher than that of the control fruit. Results showed that fruits treated on the 1st and the 3rd day after harvest could maintain the quality of melon.

Keywords: 1-MCP, muskmelon, storage, treatment.

Procedia PDF Downloads 211

Authors: Ahmed R. Abdelaziz, Zaki M. I. Osha

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Solar radiation data are of great significance for solar energy system design. This study aims at developing and calibrating new empirical models for estimating monthly mean daily global solar radiation on a horizontal surface in Alexandria, Egypt. Day length hours, sun height, day number, and declination angle calculated data are used for this purpose. A comparison between measured and calculated values of solar radiation is carried out. It is shown that all the proposed correlations are able to predict the global solar radiation with excellent accuracy in Alexandria.

Keywords: solar energy, global solar radiation, model, regression coefficient

Procedia PDF Downloads 385

Authors: Pooja Verma, Rajnesh Tyagi, Sunil Mohan

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Al-Si alloys are widely used in various components such as liner-less engine blocks, piston, compressor bodies and pumps for automobile sector and aerospace industries due to their excellent combination of properties like low thermal expansion coefficient, low density, excellent wear resistance, high corrosion resistance, excellent cast ability, and high hardness. The low density and high hardness of primary Si phase results in significant reduction in density and improvement in wear resistance of hypereutectic Al-Si alloys. Keeping in view of the industrial importance of the alloys, hypereutectic Al-Si alloys containing 14, 16, 18 and 20 wt. % of Si were prepared in a resistance furnace using adequate amount of deoxidizer and degasser and their erosion behavior was evaluated by conducting tests at impingement angles of 30°, 60°, and 90° with an erodent discharge rate of 7.5 Hz, pressure 1 bar using erosion test rig. Microstructures of the cast alloys were examined using Optical microscopy (OM) and scanning electron microscopy (SEM) and the presence of Si particles was confirmed by x-ray diffractometer (XRD). The mechanical properties and hardness were measured using uniaxial tension tests at a strain rate of 10-3/s and Vickers hardness tester. Microstructures of the alloys and X-ray examination revealed the presence of primary and eutectic Si particles in the shape of cuboids or polyhedral and finer needles. Yield strength (YS), ultimate tensile strength (UTS), and uniform elongation of the hypereutectic Al-Si alloys were observed to increase with increasing content of Si. The optimal strength and ductility was observed for Al-20 wt. % Si alloy which is significantly higher than the Al-14 wt. % Si alloy. The increased hardness and the strength of the alloys with increasing amount of Si has been attributed presence of Si in the solid solution which creates strain, and this strain interacts with dislocations resulting in solid-solution strengthening. The interactions between distributed primary Si particles and dislocations also provide Orowan strengthening leading to increased strength. The steady state erosion rate was found to decrease with increasing angle of impact as well as Si content for all the alloys except at 900 where it was observed to increase with the increase in the Si content. The minimum erosion rate is observed in Al-20 wt. % Si alloy at 300 and 600 impingement angles because of its higher hardness in comparison to other alloys. However, at 90° impingement angle the wear rate for Al-20 wt. % Si alloy is found to be the minimum due to deformation, subsequent cracking and chipping off material.

Keywords: Al-Si alloy, erosion wear, cast alloys, dislocation, strengthening

Procedia PDF Downloads 51

Authors: Arya Pirooz

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Air and fuel must be mixed correctly so that there is perfect combustion, which calls for fuel atomization by injection. In this study, the effects of different parameters such as number of orifices, length and diameter of orifices, diameter of nozzle sac and the angle of needle seat in injectors were investigated with the use of rate of injection and sac pressure. The unit pump of the OM-457 diesel engine was modelled on Avl-Hydsim. The results illustrate that the sac pressure decreased by 46% when the number of holes were doubled, although the rate of injection had an immense change. Also, the sac pressure increased up to 60% when the diameter of orifices decreased by 40% in spite of the semi-constant injection rate.

Keywords: injection, OM-457 engine, nozzle geometry, atomization

Procedia PDF Downloads 483

Authors: Zahra Kazemi Saleh, Bénédicte Poulin-Charronnat, Annie Vinter

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This study examines the effects of aging on visual statistical learning, using eye-tracking techniques to investigate this cognitive phenomenon. Visual statistical learning is a fundamental brain function that enables the automatic and implicit recognition, processing, and internalization of environmental patterns over time. Some previous research has suggested the robustness of this learning mechanism throughout the aging process, underscoring its importance in the context of education and rehabilitation for the elderly. The study included three distinct groups of participants, including 21 young adults (Mage: 19.73), 20 young-old adults (Mage: 67.22), and 17 old-old adults (Mage: 79.34). Participants were exposed to a series of 12 arbitrary black shapes organized into 6 pairs, each with different spatial configurations and orientations (horizontal, vertical, and oblique). These pairs were not explicitly revealed to the participants, who were instructed to passively observe 144 grids presented sequentially on the screen for a total duration of 7 min. In the subsequent test phase, participants performed a two-alternative forced-choice task in which they had to identify the most familiar pair from 48 trials, each consisting of a base pair and a non-base pair. Behavioral analysis using t-tests revealed notable findings. The mean score for the first group was significantly above chance, indicating the presence of visual statistical learning. Similarly, the second group also performed significantly above chance, confirming the persistence of visual statistical learning in young-old adults. Conversely, the third group, consisting of old-old adults, showed a mean score that was not significantly above chance. This lack of statistical learning in the old-old adult group suggests a decline in this cognitive ability with age. Preliminary eye-tracking results showed a decrease in the number and duration of fixations during the exposure phase for all groups. The main difference was that older participants focused more often on empty cases than younger participants, likely due to a decline in the ability to ignore irrelevant information, resulting in a decrease in statistical learning performance.

Keywords: aging, eye tracking, implicit learning, visual statistical learning

Procedia PDF Downloads 60

Authors: Fossarello Maurizio, Mattana Giorgio, Tatti Filippo.

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The most widely performed surgical procedure in Open-Angle Glaucoma (OAG) is trabeculectomy. Although this filtering procedure is extremely effective, surgical failure and postoperative complications are reported. Due to the its invasive nature and possible complications, trabeculectomy is usually reserved, in practice, for patients who are refractory to medical and laser therapy. Recently, a number of micro-invasive surgical techniques (MIGS: Micro-Invasive Glaucoma Surgery), have been introduced in clinical practice. They meet the criteria of micro-incisional approach, minimal tissue damage, short surgical time, reliable IOP reduction, extremely high safety profile and rapid post-operative recovery. Xen45 Gel Implant (Allergan, Dublin, Ireland) is one of the MIGS alternatives, and consists in a porcine gelatin tube designed to create an aqueous flow from the anterior chamber to the subconjunctival space, bypassing the resistance of the trabecular meshwork. In this study we report the results of this technique as a favorable option in the treatment of OAG for its benefits in term of efficacy and safety, either alone or in combination with cataract surgery. This is a retrospective, single-center study conducted in consecutive OAG patients, who underwent Xen45 Gel Stent implantation alone or in combination with phacoemulsification, from October 2018 to June 2019. The primary endpoint of the study was to evaluate the reduction of both IOP and number of antiglaucoma medications at 12 months. The secondary endpoint was to correlate filtering bleb morphology evaluated by means of anterior segment OCT with efficacy in IOP lowering and eventual further procedures requirement. Data were recorded on Microsoft Excel and study analysis was performed using Microsoft Excel and SPSS (IBM). Mean values with standard deviations were calculated for IOPs and number of antiglaucoma medications at all points. Kolmogorov-Smirnov test showed that IOP followed a normal distribution at all time, therefore the paired Student’s T test was used to compare baseline and postoperative mean IOP. Correlation between postoperative Day 1 IOP and Month 12 IOP was evaluated using Pearson coefficient. Thirty-six eyes of 36 patients were evaluated. As compared to baseline, mean IOP and the mean number of antiglaucoma medications significantly decreased from 27,33 ± 7,67 mmHg to 16,3 ± 2,89 mmHg (38,8% reduction) and from 2,64 ± 1,39 to 0,42 ± 0,8 (84% reduction), respectively, at 12 months after surgery (both p < 0,001). According to bleb morphology, eyes were divided in uniform group (n=8, 22,2%), subconjunctival separation group (n=5, 13,9%), microcystic multiform group (n=9, 25%) and multiple internal layer group (n=14, 38,9%). Comparing to baseline, there was no significative difference in IOP between the 4 groups at month 12 follow-up visit. Adverse events included bleb function decrease (n=14, 38,9%), hypotony (n=8, 22,2%) and choroidal detachment (n=2, 5,6%). All eyes presenting bleb flattening underwent needling and MMC injection. The higher percentage of patients that required secondary needling was in the uniform group (75%), with a significant difference between the groups (p=0,03). Xen45 gel stent, either alone or in combination with phacoemulsification, provided a significant lowering in both IOP and medical antiglaucoma treatment and an elevated safety profile.

Keywords: anterior segment OCT, bleb morphology, micro-invasive glaucoma surgery, open angle glaucoma, Xen45 gel implant

Procedia PDF Downloads 126

Authors: Salomão Manuel Francisco, Manuel António Salgueiro Da Silva, Bento Filipe Barreiras Pinto Cavadas, Teresa Monteiro Seixas

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In bachelor's degrees in Physics Education framework in Angola, and to a certain extent, within the community of Portuguese language countries (CPLP), teaching methodologies rely heavily on theoretical memorization and mathematical demonstrations. This approach often discourages students, particularly the female population, as the reliance on theoretical mathematical demonstrations generates the perception of Physics as an arduous, challenging discipline. To address this challenge and recognize the value of practical application as an evaluative criterion of material truth, we propose a practical activity in Environmental Physics that will be shared with Angolan higher education teachers, who will receive full scaffolding and support from the authors. These teachers, adopting and developing similar activities in a classroom setting, will contribute to the environmental education framework as well. Additionally, this work aligns with different goals of UNESCO's 2030 agenda, namely, specifically, goals 4, 5, 7, 11, 13, and 17. The experimental activity developed in this work is centered around the demonstration of the photovoltaic effect and its application for renewable energy production. The first objective of the activity is to study the variation of electrical power supplied by a photovoltaic system (PV) to an electrical circuit as the angle of light incidence changes. Students can observe that the power supplied to the circuit is greater when light rays fall perpendicularly on the PV. However, as the angle of incidence increases, resulting in a larger area covered by the light rays, the power supplied to the circuit decreases due to lower irradiance. The second objective is to demonstrate that the power output can be maximized by adjusting the circuit load resistance at each irradiance value. In these two parts of the activity, students can analyze experimental data taking into account the irradiance law and the equivalent circuit description of a PV cell. Through detailed data analysis, students are also expected to assess the effects of temperature on PV efficiency degradation and the efficiency enhancement provided by light concentration mechanisms. As a third objective, students can explore how the color of incident light affects the PV output power, considering the quantum nature of light and its interaction with the PV system.

Keywords: experiments, irradiation law, physic teaching, photovoltaic effect

Procedia PDF Downloads 67

Authors: Kim Ji-Hyun, Jeon Hye-Seon, Kwon Oh-Yun, Park Eun-Young, Hwang Ui-Jae, Gwak Gyeong-Tae, Yoon Hyeo-Bin

Abstract:

Stress urinary incontinence (SUI), a common women health problem, is an involuntary leakage of urine while sneezing, coughing, or physical exertion caused by insufficient strength of the pelvic floor and sphincter muscles. SUI also leads to decrease in quality of life and limits sexual activities. SUI is related to the increased bladder neck angle, bladder neck movement, funneling index, urethral width, and decreased urethral length. Various pelvic floor muscle electrical stimulation (ES) interventions have been applied to improve the symptoms of the people with SUI. ES activates afferent fibers of pudendal nerve and smoothly induces contractions of the pelvic floor muscles such as striated periurethral muscles and striated pelvic floor muscles. ES via intravaginal electrodes are the most frequently used types of the pelvic floor muscle ES for the female SUI. However, inserted electrode is uncomfortable and it increases the risks of infection. The purpose of this preliminary study was to determine if the 8-week transcutaneous pelvic floor ES would be effective to improve the symptoms and satisfaction of the females with SUI. Easy-K, specially designed ES equipment for the people with SUI, was used in this study. The oval shape stimulator can be placed on a toilet seat, and the surface has invaded electrode fit to contact with the entire vulva area while users are sitting on the stimulator. Five women with SUI were included in this experiment. Prior to the participation, subjects were instructed about procedures and precautions in using the ES. They have used the stimulator once a day for 20 minutes for each session at home. Outcome data was collected 3 times at the baseline, 4 weeks and 8 weeks after the intervention. Intravaginal sonography was used to measure the bladder neck angle, bladder neck movement, funneling index, thickness of an anterior rhabdosphincter and a posterior rhabdosphincter, urethral length, and urethral width. Leavator ani muscle (LAM) contraction strength was assessed by manual palpation according to the oxford scoring system. In addition, incontinence quality of life (IQOL) and female sexual function index (FSFI) questionnaires were used to obtain addition subjective information. Friedman test, a nonparametric statistical test, was used to determine the effectiveness of the ES. The Wilcoxon test was used for the post-hoc analysis and the significance level was set at .05. The bladder neck angle, funneling index and urethral width were significantly decreased after 8-weeks of intervention (p<.05). LAM contraction score, urethral length and anterior and posterior rhabdosphicter thickness were statistically increased by the intervention (p<.05). However, no significant change was found in the bladder neck movement. Although total score of the IQOL did not improve, the score of the ‘avoidance’ subscale of IQOL had significant improved (p<.05). FSFI had statistical difference in FSFI total score and ‘desire’ subscale (p<.05). In conclusion, 8-week use of a transcutaneous ES on peri-vulva area improved dynamic mechanical structures of the pelvic floor musculature as well as IQOL and conjugal relationship.

Keywords: electrical stimulation, Pelvic floor muscle, sonography, stress urinary incontinence, women health

Procedia PDF Downloads 135

Authors: Emin Gundogar, Burak Erkayman, Nusret Sazak

Abstract:

Providing effective management performance through the whole supply chain is critical issue and hard to applicate. The proper evaluation of integrated data may conclude with accurate information. Analysing the supply chain data through OLAP (On-Line Analytical Processing) technologies may provide multi-angle view of the work and consolidation. In this study, association rules and classification techniques are applied to measure the supply chain performance metrics of an automotive manufacturer in Turkey. Main criteria and important rules are determined. The comparison of the results of the algorithms is presented.

Keywords: supply chain performance, performance measurement, data mining, automotive

Procedia PDF Downloads 492