Search results for: shape measure

Authors: Asma A. Ben Ahmed, Hajer M. Alborawy, Alaa A. Mashina, Pradeep K. Velautham, Abdulmonem Gobassa, Emhemmed Elgallal, Mohamed N. El Attug

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Generic medicines are those where patent protection has expired, and which may be produced by manufacturers other than the innovator company. Use of generic medicines has been increasing in recent years, primarily as a cost saving measure in healthcare provision. Generic medicines are typically 20 – 90 % cheaper than originator equivalents. Physicians often continue to prescribe brand-name drugs to their patients even when less expensive pharmacologically equivalent generic drugs are available. Because generics are less expensive than their brand-name counterparts, the cost-savings to the patient is not the only factor that physicians consider when choosing between generic and brand-name drugs. Unfortunately Physicians in general and Libyan Physicians in particular tend to prescribe brand-name drugs, even without evidence of their therapeutic superiority, because neither they nor their insured patients bear these drugs’ increased cost with respect to generic substitutes. This study is to compare the quality of five different prednisolone tablets of the same strength from different companies under different trade names: Julphar, October pharma, Akums, Actavis, Pfizer compared them with pure prednisolone reference (BPCRS).

Keywords: quality control, pharmaceutical analysis, generic medicines, prednisolone

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Authors: Prittesh Patel, Ramar Krishnamurthy

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In the present study, nine strains of C. falcatum obtained from different places and cultivars were characterized for sporulation, growth rate, and 18S rRNA gene sequence. All isolates had characteristic fast-growing sparse and fleecy aerial mycelia on potato dextrose agar with sickle shape conidia (length x width: varied from 20.0 X 3.89 to 25.52 X 5.34 μm) and blackish to orange acervuli with setae (length x width: varied from 112.37X 2.78 to 167.66 X 6.73 μm). They could be divided into two groups on the base of morphology; P1, dense mycelia with concentric growth and P2, sparse mycelia with uneven growth. Genomic DNA isolation followed by PCR amplification with ITS1 and ITS4 primer produced ~550bp amplicons for all isolates. Phylogeny generated by 18S rRNA gene sequence confirmed the variation in isolates and mainly grouped into two clusters; cluster 1 contained CoC671 isolates (cfNAV and cfPAR) and Co86002 isolate (cfTIM). Other isolates cfMAD, cfKAM, and cfMAR were grouped into cluster 2. Remaining isolates did not fall into any cluster. Isolate cfGAN, collected from Co86032 was found highly diverse of all the nine isolates. In a nutshell, we found considerable genetic divergence and morphological variation within C. falcatum accessions collected from different areas of south Gujarat, India and these can be used for the breeding program.

Keywords: Colletotrichum falcatum, ITS, morphology, red rot, sugarcane

Procedia PDF Downloads 114

Authors: Huijing Wen, Daibao Guo

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Writing is thought to be the most complex facet of language arts. Assessing writing is difficult and subjective, and there are few scientifically validated assessments exist. Research has proposed evaluating writing using a multidimensional approach, including both qualitative and quantitative measures of handwriting, spelling and prose. Given that narrative writing has historically been a staple of literacy instruction in primary grades and is one of the three major genres Common Core State Standards required students to acquire starting in kindergarten, it is essential for teachers to understand how to measure beginning writers writing development and sources of writing difficulties through narrative writing. Guided by the theoretical models of early written expression and using empirical data, this study examines ways teachers can enact a comprehensive approach to understanding beginning writer’s narrative writing through three writing rubrics developed for a Curriculum-based Measurement (CBM). The goal is to help classroom teachers structure a framework for assessing early writing in primary classrooms. Participants in this study included 380 first-grade students from 50 classrooms in 13 schools in three school districts in a Mid-Atlantic state. Three writing tests were used to assess first graders’ writing skills in relation to both transcription (i.e., handwriting fluency and spelling tests) and translational skills (i.e., a narrative prompt). First graders were asked to respond to a narrative prompt in 20 minutes. Grounded in theoretical models of earlier expression and empirical evidence of key contributors to early writing, all written samples to the narrative prompt were coded three ways for different dimensions of writing: length, quality, and genre elements. To measure the quality of the narrative writing, a traditional holistic rating rubric was developed by the researchers based on the CCSS and the general traits of good writing. Students' genre knowledge was measured by using a separate analytic rubric for narrative writing. Findings showed that first-graders had emerging and limited transcriptional and translational skills with a nascent knowledge of genre conventions. The findings of the study provided support for the Not-So-Simple View of Writing in that fluent written expression, measured by length and other important linguistic resources measured by the overall quality and genre knowledge rubrics, are fundamental in early writing development. Our study echoed previous research findings on children's narrative development. The study has practical classroom application as it informs writing instruction and assessment. It offered practical guidelines for classroom instruction by providing teachers with a better understanding of first graders' narrative writing skills and knowledge of genre conventions. Understanding students’ narrative writing provides teachers with more insights into specific strategies students might use during writing and their understanding of good narrative writing. Additionally, it is important for teachers to differentiate writing instruction given the individual differences shown by our multiple writing measures. Overall, the study shed light on beginning writers’ narrative writing, indicating the complexity of early writing development.

Keywords: writing assessment, early writing, beginning writers, transcriptional skills, translational skills, primary grades, simple view of writing, writing rubrics, curriculum-based measurement

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Authors: Chaithanya Pothuganti

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Open and semi-open spaces in educational buildings like corridors, mid landings, seating spaces, lobby, courtyards are traditionally have been the places of social communion and interaction which helps in promoting the knowledge, performance, activeness, and motivation in students. Factors like availability of land, commercialization, of educational facilities, especially in e-techno and smart schools, led to closed classrooms to accommodate students thereby lack quality open and semi-open spaces. This insufficient attention towards open space design which is a means of informal learning misses an opportunity to encourage the student’s skill development, behavior and learning skills. The core objective of this paper is to find the level of impact on student learning behavior and to identify the suitable proportions and configuration of spaces that shape the schools. In order to achieve this, different types of open spaces in schools and their impact on student’s performance in various existing models are analysed using case studies to draw some design principles. The study is limited to indoor open spaces like corridors, break out spaces and courtyards. The expected outcome of the paper is to suggest better design considerations for the development of semi-open and open spaces which functions as an element for informal learnings. Its focus is to provide further thinking on designing and development of open spaces in educational buildings.

Keywords: configuration of spaces and proportions, informal learning, open spaces, schools, student’s behavior

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Authors: N. Marzban, J. K. Heydarzadeh M. Pourmohammadbagher, M. H. Hatami, A. Samia

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A nano-alumina-zirconia composite catalyst was synthesized by a simple aqueous sol-gel method using AlCl₃.6H₂O and ZrCl₄ as precursors. Thermal decomposition of the precursor and subsequent formation of γ-Al₂O₃ and t-Zr were investigated by thermal analysis. XRD analysis showed that γ-Al₂O₃ and t-ZrO₂ phases were formed at 700 °C. FT-IR analysis also indicated that the phase transition to γ-Al₂O₃ occurred in corroboration with X-ray studies. TEM analysis of the calcined powder revealed that spherical particles were in the range of 8-12 nm. The nano-alumina-zirconia composite particles were mesoporous and uniformly distributed in their crystalline phase. In order to measure the catalytic activity, esterification reaction was carried out. Biodiesel, as a renewable fuel, was formed in a continuous packed column reactor. Free fatty acid (FFA) was esterified with ethanol in a heterogeneous catalytic reactor. It was found that the synthesized γ-Al₂O₃/ZrO₂ composite had the potential to be used as a heterogeneous base catalyst for biodiesel production processes.

Keywords: nano alumina-zirconia, composite catalyst, thin film, biodiesel

Procedia PDF Downloads 215

Authors: Jiří Kubásek, Peter Minárik, Klára Hosová, Stanislav Šašek, Jozef Veselý, Jitka Stráská, Drahomír Dvorský, Dalibor Vojtěch, Miloš Janeček

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Mg-2Y-2Gd-1Ca and Mg-4Y-4Gd-2Ca alloys were processed by extrusion or equal channel angular pressing (ECAP) to analyse the effect of the microstructure on ignition temperature, mechanical properties and corrosion resistance. The alloys are characterized by good mechanical properties and exceptionally high ignition temperature, which is a critical safety measure. The effect of extrusion and ECAP on the microstructure, mechanical properties and ignition temperature was studied. The obtained results indicated a substantial effect of the processing conditions on the average grain size, the recrystallized fraction and texture formation. Both alloys featured a high strength, depending on the composition and processing condition, and a high ignition temperature of ≈1100 °C (Mg-4Y-4Gd-2Ca) and ≈950 °C (Mg-2Y-2Gd-1Ca), which was attributed to the synergic effect of Y, Gd and Ca oxides, with the dominant effect of Y₂O₃. The achieved combination of enhanced mechanical properties and the ignition temperature makes these alloys a prominent candidate for aircraft applications.

Keywords: magnesium alloys, enhanced ignition temperature, mechanical properties, ECAP

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Authors: Ali A. Alshahrani

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This study aims to identify Saudi English as a Foreign Language (EFL) students' perspectives towards using the English language in their studies. The study explores students' self-confident and its association with students' actual performance in English courses in their different academic programs. A multimodal methodology was used to fulfill the research purpose and answer the research questions. A 25-item survey questionnaire and final examination grades were used to collect data. Two hundred forty-one students agreed to participate in the study. They completed the questionnaire and agreed to release their final grades to be a part of the collected data. The data were coded and analyzed by SPSS software. The findings indicated a significant difference in students' performance in English courses between participants' academic programs on the one hand. Students' self-confidence in their English language skills, on the other hand, was not significantly different between participants' academic programs. Data analysis also revealed no correlational relationship between students' self-confidence level and their language skills and their performance. The study raises more questions about other vital factors such as course instructors' views of the materials, faculty members of the target department, family belief in the usefulness of the program, potential employers. These views and beliefs shape the student's preparation process and, therefore, should be explored further.

Keywords: English language intensive program, language proficiency, performance, self-confidence

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Authors: Yasunori Kobori, Li Quan, Shu Wu, Nizam Mohyar, Zachary Nosker, Nobukazu Tsukiji, Nobukazu Takai, Haruo Kobayashi

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This paper proposes an electrolytic capacitor-less transformer-less AC-DC LED driver with a current ripple canceller. The proposed LED driver includes a diode bridge, a buck-boost converter, a negative feedback controller and a current ripple cancellation circuit. The current ripple canceller works as a bi-directional current converter using a sub-inductor, a sub-capacitor and two switches for controlling current flow. LED voltage is controlled in order to regulate LED current by the negative feedback controller using a current sense resistor. There are two capacitors which capacitance of 5 uF. We describe circuit topologies, operation principles and simulation results for our proposed circuit. In addition, we show the line regulation for input voltage variation from 85V to 130V. The output voltage ripple is 2V and the LED current ripple is 65 mA which is less than 20% of the typical current of 350 mA. We are now making the proposed circuit on a universal board in order to measure the experimental characteristics.

Keywords: LED driver, electrolytic, capacitor-less, AC-DC converter, buck-boost converter, current ripple canceller

Procedia PDF Downloads 454

Authors: A. Soualem

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The design of multi stage deep drawing processes requires the evaluation of many process parameters such as the intermediate die geometry, the blank shape, the sheet thickness, the blank holder force, friction, lubrication etc..These process parameters have to be determined for the optimum forming conditions before the process design. In general sheet metal forming may involve stretching drawing or various combinations of these basic modes of deformation. It is important to determine the influence of the process variables in the design of sheet metal working process. Especially, the punch and die corner for deep drawing will affect the formability. At the same time the prediction of sheet metals springback after deep drawing is an important issue to solve for the control of manufacturing processes. Nowadays, the importance of this problem increases because of the use of steel sheeting with high stress and also aluminum alloys. The aim of this paper is to give a better understanding of the springback and its effect in various sheet metals forming process such as expansion and restraint deep drawing in the cup drawing process, by varying radius die, lubricant for two commercially available materials e.g. galvanized steel and Aluminum sheet. To achieve these goals experiments were carried out and compared with other results. The original of our purpose consist on tests which are ensured by adapting a U-type stretching-bending device on a tensile testing machine, where we studied and quantified the variation of the springback.

Keywords: springback, deep drawing, expansion, restricted deep drawing

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Authors: Marwin M. Dela Cruz

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Aviation as a transport sector is supportive of the seventeen (17) Sustainable Goals espoused by the United Nations. Air Transport Action Group (ATAG) states that over 18.1 million indirect jobs globally were sustained through the purchase of goods and services by companies in the aviation industry. This supply chain activity contributed approximately $816.4 billion to global GDP. This was achieved through numerous actions to lessen economic uncertainty and challenges. Its impact is not just a by-product of economic activity but of the facilities it generates. As the aviation industry is unifying its efforts, education and training should also come with it. The need for aviation education and training and a well-crafted regulatory policy initiated by lawmakers can provide a better aviation education. The Philippine State College of Aeronautics (PhilSCA), being the only government Higher Education Institution (HEI) in the Philippines, is given a very distinct congressional mandate to offer aviation-related courses to afford those in the aviation industry the opportunity to pursue studies. Having this, the industry has become the precursor and venue of present-day communities. In addition, it becomes an essential measure of a better life.

Keywords: Philippine state college of aeronautics, aviation industry, sustainable goals, aviation education

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Authors: Nathakhun Wiroonsri

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There are various cluster validity measures used for evaluating clustering results. One of the main objectives of using these measures is to seek the optimal unknown number of clusters. Some measures work well for clusters with different densities, sizes and shapes. Yet, one of the weaknesses that those validity measures share is that they sometimes provide only one clear optimal number of clusters. That number is actually unknown and there might be more than one potential sub-optimal option that a user may wish to choose based on different applications. We develop two new cluster validity indices based on a correlation between an actual distance between a pair of data points and a centroid distance of clusters that the two points are located in. Our proposed indices constantly yield several peaks at different numbers of clusters which overcome the weakness previously stated. Furthermore, the introduced correlation can also be used for evaluating the quality of a selected clustering result. Several experiments in different scenarios, including the well-known iris data set and a real-world marketing application, have been conducted to compare the proposed validity indices with several well-known ones.

Keywords: clustering algorithm, cluster validity measure, correlation, data partitions, iris data set, marketing, pattern recognition

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Authors: Pramod Ghadge, Swadesh Srivastava

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Revenue generation of a logistics company depends on how the logistics cost of a shipment is calculated. Logistics cost of a shipment is a function of distance & speed of the shipment travel in a particular network, its volumetric size and dead weight. Logistics billing is based mainly on the consumption of the scarce resource (space or weight carrying capacity of a carrier). Shipment’s size or deadweight is a function of product and packaging weight, dimensions and flexibility. Hence, to arrive at a standard methodology to compute accurate cost to bill the customer, the interplay among above mentioned physical attributes along with their measurement plays a key role. This becomes even more complex for an ecommerce company, like Flipkart, which caters to shipments from both warehouse and marketplace in an unorganized non-standard market like India. In this paper, we will explore various methodologies to define a standard way of billing the non-standard shipments across a wide range of size, shape and deadweight. Those will be, usage of historical volumetric/dead weight data to arrive at a factor which can be used to compute the logistics cost of a shipment, also calculating the real/contour volume of a shipment to address the problem of irregular shipment shapes which cannot be solved by conventional bounding box volume measurements. We will also discuss certain key business practices and operational quality considerations needed to bring standardization and drive appropriate ownership in the ecosystem.

Keywords: contour volume, logistics, real volume, volumetric weight

Procedia PDF Downloads 251

Authors: Z. N. Haji, S. O. Oyadiji, H. Samami, O. Farrell

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The prediction of the vibration response of rubber products by analytical or numerical method depends mainly on the predefined intrinsic material properties such as Young’s modulus, damping factor and Poisson’s ratio. Such intrinsic properties are determined experimentally by subjecting a bonded rubber sample to compression tests. The compression tests on such a sample yield an apparent Young’s modulus which is greater in magnitude than the intrinsic Young’s modulus of the rubber. As a result, many analytical equations have been developed to determine Young’s modulus from an apparent Young’s modulus of bonded rubber materials. In this work, the applicability of some of these analytical equations is assessed via experimental testing. The assessment is based on testing of vulcanized nitrile butadiene rubber (NBR70) samples using tensile test and compression test methods. The analytical equations are used to determine the intrinsic Young’s modulus from the apparent modulus that is derived from the compression test data of the bonded rubber samples. Then, these Young’s moduli are compared with the actual Young’s modulus that is derived from the tensile test data. The results show significant discrepancy between the Young’s modulus derived using the analytical equations and the actual Young’s modulus.

Keywords: bonded rubber, quasi-static test, shape factor, apparent Young’s modulus

Procedia PDF Downloads 157

Authors: Karim Sobh, Khaled El-Ayat, Fady Morcos, Amr El-Kadi

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Distributed applications deployed on LEO satellites and ground stations require substantial communication between different members in a constellation to overcome the earth coverage barriers imposed by GEOs. Applications running on LEO constellations suffer the earth line-of-sight blockage effect. They need adequate lab testing before launching to space. We propose a scalable cloud-based net-work simulation framework to simulate problems created by the earth line-of-sight blockage. The framework utilized cloud IaaS virtual machines to simulate LEO satellites and ground stations distributed software. A factorial ANOVA statistical analysis is conducted to measure simulator overhead on overall communication performance. The results showed a very low simulator communication overhead. Consequently, the simulation framework is proposed as a candidate for testing LEO constellations with distributed software in the lab before space launch.

Keywords: LEO, cloud computing, constellation, satellite, network simulation, netfilter

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Authors: Annop Jaewisorn

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This study explores the relationship between natural disasters and inequalities -both income and expenditure inequality- at a micro-level of Thailand as the first study of this nature for this country. The analysis uses a unique panel and remote-sensing dataset constructed for the purpose of this research. It contains provincial inequality measures and other economic and social indicators based on the Thailand Household Survey during the period between 1992 and 2019. Meanwhile, the data on natural disasters, which are remote-sensing data, are received from several official geophysical or meteorological databases. Employing a panel fixed effects, the results show that natural disasters significantly reduce household income and expenditure inequality as measured by the Gini index, implying that rich people in Thailand bear a higher cost of natural disasters when compared to poor people. The effect on income inequality is mainly driven by droughts, while the effect on expenditure inequality is mainly driven by flood events. The results are robust across heterogeneity of the samples, lagged effects, outliers, and an alternative inequality measure.

Keywords: inequality, natural disasters, remote-sensing data, Thailand

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Authors: Rims Janeliukstis, Deniss Mironovs, Andrejs Kovalovs

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Operational Modal Analysis (OMA) is widely applied as a method for Structural Health Monitoring for structural damage identification and assessment by tracking the changes of the identified modal parameters over time. Unfortunately, modal parameters also depend on such external factors as temperature and loads. Any structural condition assessment using modal parameters should be done taking into consideration those external factors, otherwise there is a high chance of false positives. A method of structural reliability assessment based on anomaly detection technique called Machalanobis Squared Distance (MSD) is proposed. It requires a set of reference conditions to learn healthy state of a structure, which all future parameters are compared to. In this study, structural modal parameters (natural frequency and mode shape), as well as ambient temperature and loads acting on the structure are used as features. Numerical tests were performed on a finite element model of a carbon fibre reinforced polymer composite beam with delamination damage at various locations and of various severities. The advantages of the demonstrated approach include relatively few computational steps, ability to distinguish between healthy and damaged conditions and discriminate between different damage severities. It is anticipated to be promising in reliability assessment of massively produced structural parts.

Keywords: operational modal analysis, reliability assessment, anomaly detection, damage, mahalanobis squared distance

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Authors: Diego Roberto Goncalves De Pontes, Sergio Donizetti Zorzo

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Studies show that most users do not read privacy policies from the online services they use. Some authors claim that one of the main causes of this is that policies are long and usually hard to understand, which make users lose interest in reading them. In this scenario, users may agree with terms without knowing what kind of data is being collected and why. Given that, we aimed to develop a model that would present the privacy policies contents in an easy and graphical way for the user to understand. We call it the Privacy Label. Using information recovery techniques, we propose an architecture that is able to extract information about what kind of data is being collected and to what end in the policies and show it to the user in an automated way. To assess our model, we calculated the precision, recall and f-measure metrics on the information extracted by our technique. The results for each metric were 68.53%, 85.61% e 76,13%, respectively, making it possible for the final user to understand which data was being collected without reading the whole policy. Also, our proposal can facilitate the notice-and-choice by presenting privacy policy information in an alternative way for online users.

Keywords: privacy, policies, user behavior, computer human interaction

Procedia PDF Downloads 291

Authors: Ebru Acuner, Gulgun Kayakutlu, M. Ozgur Kayalica, Sermin Onaygil

Abstract:

In Turkey, emigration, especially from Syria, has been continuously increasing together with rapid urbanization. In parallel to this, total energy consumption has been growing, rapidly. Unfortunately, domestic energy sources could not meet this energy demand. Hence, there is a need for reliable predictions. For this reason, before making a survey study for the migrated people, an informative questionnaire was prepared to take the opinions of the experts on the main drivers that shape the energy consumption behavior of the migrated people. Totally, 17 experts were answered, and they were analyzed by means of Netica program considering Bayesian belief analysis method. In the analysis, factors affecting energy consumption behaviors as well as strategies, institutions, tools and financing methods to change these behaviors towards efficient consumption were investigated. On the basis of the results, it can be concluded that changing the energy consumption behavior of the migrated people is crucial. In order to be successful, electricity and natural gas prices and tariffs in the market should be arranged considering energy efficiency. In addition, support mechanisms by not only the government but also municipalities should be taken into account while preparing related policies. Also, electric appliance producers should develop and implement strategies and action in favor of the usage of more efficient appliances. Last but not least, non-governmental organizations should support the migrated people to improve their awareness on the efficient consumption for the sustainable future.

Keywords: Bayesian belief, behavior, energy consumption, energy efficiency, migrated people

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Authors: M. R. Abusrea, Shiyi Jiang, Dingding Chen, Kazuo Arakawa

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Novel wind-lens turbine designs can augment power output. Vacuum-Assisted Resin Transfer Molding (VARTM) is used to form large and complex structures from a Carbon Fiber Reinforced Polymer (CFRP) composite. Typically, wind-lens turbine structures are fabricated in segments, and then bonded to form the final structure. This paper introduces five new adhesive joints, divided into two groups: One is constructed between dry carbon and CFRP fabrics, and the other is constructed with two dry carbon fibers. All joints and CFRP fabrics were made in our laboratory using VARTM manufacturing techniques. Specimens were prepared for tensile testing to measure joint performance. The results showed that the second group of joints achieved a higher tensile strength than the first group. On the other hand, the tensile fracture behavior of the two groups showed the same pattern of crack originating near the joint ends followed by crack propagation until fracture.

Keywords: adhesive joints, CFRP, VARTM, resin transfer molding

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Authors: Seyed Reza Agha Seyed Hosseini, Nicolas Hamelin

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Many marketing executives are looking for a comprehensive plan for delivering quality services and products that will create a distinct and unforgettable long-term experience for customers in dealing with their brand. Various brand management experts believe that a company looking to enhance its brand experience in the minds of customers should have a plan to increase customer satisfaction as well as customer loyalty. The purpose of this research was to investigate the role of brand experience in customer satisfaction and customer loyalty in Ayandeh Bank branches in Tehran. The study employed a quantitative methodology. For data gathering, a questionnaire was utilised to measure all the variables of the research. The statistical population of the study consisted of all the customers of Ayandeh Bank branches in Tehran, and the study data was gathered from 400 respondents. The findings indicate that brand experience has a direct and meaningful impact on customer satisfaction and customer loyalty, and, furthermore, that customer satisfaction has a direct and significant effect on customer loyalty in the branches of Ayandeh Bank in Tehran.

Keywords: brand experience, customer satisfaction, customer loyalty, bank

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Authors: Mustapha Sadouk

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This study investigates the sensitivity of high-frequency acoustic parameters in a rigid air-saturated porous bilayer material within the framework of the equivalent fluid theory, a specific case of the Biot model. The study specifically focuses on the sensitivity analysis in the frequency domain. The interaction between the fluid and solid phases of the porous medium incorporates visco-inertial and thermal exchange, characterized by two functions: the dynamic tortuosity α(ω) proposed by Johnson et al. and the dynamic compressibility β(ω) proposed by Allard, refined by Sadouki for the low-frequency domain of ultrasound. The parameters under investigation encompass porosity, tortuosity, viscous characteristic length, thermal characteristic length, as well as viscous and thermal shape factors. A +30% variation in these parameters is considered to assess their impact on the transmitted wave amplitudes. By employing this larger variation, a more comprehensive understanding of the sensitivity of these parameters is obtained. The outcomes of this study contribute to a better comprehension of the high-frequency wave behavior in porous bilayer materials, providing valuable insights for the design and optimization of such materials across various applications.

Keywords: bilayer materials, ultrasound, sensitivity analysis, equivalent fluid theory, dynamic tortuosity., porous material

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Authors: Mbugua R. N., Salim R. W., Ndambuki J. M.

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Natural admixtures provide concrete with enhanced properties but their processing end up making them very expensive resulting in increase to cost of concrete. In this study the effect of Gum from Acacia Karroo (GAK) as set-retarding admixture in cement pastes was studied. The possibility of using GAK as water reducing admixture both in cement mortar concrete was also investigated. Cement pastes with different dosages of GAK were prepared to measure the setting time using different dosages. Compressive strength of cement mortars with 0.7, 0.8 and 0.9% weight of cement and w/c ratio of 0.5 were compared to those with water cement (w/c) ratio of 0.44 but same dosage of GAK. Concrete samples were prepared using higher dosages of GAK (1, 2 and 3\% wt of cement) and a water bidder (w/b) of 0.61 were compared to those with the same GAK dosage but with reduced w/b ratio. There was increase in compressive strength of 9.3% at 28 days for cement mortar samples with 0.9% dosage of GAK and reduced w/c ratio.

Keywords: compressive strength, Gum Acacia Karroo, retarding admixture, setting time, water-reducing admixture

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Authors: Moustafa Shawkey, Ahmed G. El-Deen, H. M. Mahmoud, M. M. Rashad

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Piezoelectric based cement nanocomposite is a promising technology for generating an electric charge upon mechanical stress of concrete structure. Moreover, piezoelectric nanomaterials play a vital role for providing accurate system of structural health monitoring (SHM) of the concrete structure. In light of increasing awareness of environmental protection and energy crises, generating renewable and green energy form cement based on piezoelectric nanomaterials attracts the attention of the researchers. Herein, we introduce a facial synthesis for bismuth ferrite nanoparticles (BiFeO3 NPs) as piezoelectric nanomaterial via sol gel strategy. The fabricated piezoelectric nanoparticles are uniformly distributed to cement-based nanomaterials with different ratios. The morphological shape was characterized by field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HR-TEM) as well as the crystal structure has been confirmed using X-ray diffraction (XRD). The ferroelectric and magnetic behaviours of BiFeO3 NPs have been investigated. Then, dielectric constant for the prepared cement samples nanocomposites (εr) is calculated. Intercalating BiFeO3 NPs into cement materials achieved remarkable results as piezoelectric cement materials, distinct enhancement in ferroelectric and magnetic properties. Overall, this present study introduces an effective approach to improve the electrical properties based cement applications.

Keywords: piezoelectric nanomaterials, cement technology, bismuth ferrite nanoparticles, dielectric

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Authors: Naghmeh M. Bandari, Javad Dargahi, Muthukumaran Packirisamy

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Robot-assisted minimally invasive surgery (RMIS) has been widely performed around the world during the last two decades. RMIS demonstrates significant advantages over conventional surgery, e.g., improving the accuracy and dexterity of a surgeon, providing 3D vision, motion scaling, hand-eye coordination, decreasing tremor, and reducing x-ray exposure for surgeons. Despite benefits, surgeons cannot touch the surgical site and perceive tactile information. This happens due to the remote control of robots. The literature survey identified the lack of force feedback as the riskiest limitation in the existing technology. Without the perception of tool-tissue contact force, the surgeon might apply an excessive force causing tissue laceration or insufficient force causing tissue slippage. The primary use of force sensors has been to measure the tool-tissue interaction force in real-time in-situ. Design of a tactile sensor is subjected to a set of design requirements, e.g., biocompatibility, electrical-passivity, MRI-compatibility, miniaturization, ability to measure static and dynamic force. In this study, a planar optical fiber-based sensor was proposed to mount at the surgical grasper. It was developed based on the light intensity modulation principle. The deflectable part of the sensor was a beam modeled as a cantilever Euler-Bernoulli beam on rigid substrates. A semi-cylindrical indenter was attached to the bottom surface the beam at the mid-span. An optical fiber was secured at both ends on the same rigid substrates. The indenter was in contact with the fiber. External force on the sensor caused deflection in the beam and optical fiber simultaneously. The micro-bending of the optical fiber would consequently result in light power loss. The sensor was simulated and studied using finite element methods. A laser light beam with 800nm wavelength and 5mW power was used as the input to the optical fiber. The output power was measured using a photodetector. The voltage from photodetector was calibrated to the external force for a chirp input (0.1-5Hz). The range, resolution, and hysteresis of the sensor were studied under monotonic and harmonic external forces of 0-2.0N with 0 and 5Hz, respectively. The results confirmed the validity of proposed sensing principle. Also, the sensor demonstrated an acceptable linearity (R2 > 0.9). A minimum external force was observed below which no power loss was detectable. It is postulated that this phenomenon is attributed to the critical angle of the optical fiber to observe total internal reflection. The experimental results were of negligible hysteresis (R2 > 0.9) and in fair agreement with the simulations. In conclusion, the suggested planar sensor is assessed to be a cost-effective solution, feasible, and easy to use the sensor for being miniaturized and integrated at the tip of robotic graspers. Geometrical and optical factors affecting the minimum sensible force and the working range of the sensor should be studied and optimized. This design is intrinsically scalable and meets all the design requirements. Therefore, it has a significant potential of industrialization and mass production.

Keywords: force sensor, minimally invasive surgery, optical sensor, robotic surgery, tactile sensor

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Authors: Shaibu Salifu, Ofori Boachie

Abstract:

Philanthropy is part and parcel of African identity; it is intrinsically embedded in the life of Africans where at any point in time people contribute to philanthropy through giving or receiving. Even though, research on corporate philanthropy has gained attention in the academic space of Ghana, little have been done on the effects of corporate foundation giving on female labour force participation in Ghana. We investigate the effects of corporate foundations giving on female labour force participation in Ghana. We applied convenient and purposive sampling techniques to collect qualitative data from thirty (30) women in Ghana through interviews and open-ended questionnaires. We used Nvivo to carryout analysis on the data and our results indicate that corporate foundation giving has significant effect on female labour force participation in Ghana. In addition, contrary to the feminization U-Shape Hypothesis, evidence suggest that, to a larger extent marriage and fertility (birth) of women positively contribute to the female labour force participation in Ghana. Nevertheless, the study was limited by the number of women who were interviewed, time constraints of women for elaborate discussions on the issues (constructs) of the study and fear of victimization by authorities on most of their responses to the interviews. The findings have implications for all stakeholders of philanthropy: academia, governments, civil society organizations, corporate foundations, women of Ghana and other relevant bodies.

Keywords: corporate philanthropy, corporate foundations, corporate foundation giving, female labour force participation, women, Ghana

Procedia PDF Downloads 68

Authors: Zaheer Ahmad, Afzal Shah

Abstract:

pH responsive block copolymers consist of mPEG and glutamic acid units were syntheiszed in different formulations. The synthesized polymers were structurally investigated. Doxorubicin Hydrocholide (DOX-HCl) as a chemotherapy medication for the treatment of cancer was selected. DOX-HCl was loaded and their drug loading content and drug loading efficiency were determined. The nanocarriers were obtained in small size, well shaped and slightly negative surface charge. The release study was carried out both at pH 7.4 and 5.5 and it was revealed that the release was sustained and in controlled manner and there was no initial burst release. The in vitro release study was further carried out for different formulations with different glutamic acid moieties. Time dependent cell proliferation inhibition of the free drug and drug loaded nanoparticles against human breast cancer cell lines MCF-7 and Zr-75-30 was observed. Cellular uptakes and endocytosis were investigated by confocal laser scanning microscopy (CLSM) and flow cytometery. The biocompatibility, optimum size, shape and surface charge of the developed nanoparticles make the nanoparticles an efficient drug delivery carrier.

Keywords: doxorubicin, glutamic acid, cell proliferation inhibition, breast cancer cell

Procedia PDF Downloads 126

Authors: W. H. Zheng, J. Li, F. J. Hong

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Thin liquid film evaporation in ultrathin nanoporous membranes, which reduce the viscous resistance while still maintaining high capillary pressure and efficient liquid delivery, is a promising thermal management approach for high-power electronic devices cooling. Given the challenges and technical limitations of experimental studies for accurate interface temperature sensing, complex manufacturing process, and short duration of membranes, a dimensionless lattice Boltzmann method capable of restoring thermophysical properties of working fluid is particularly derived. The evaporation of R134a to its pure vapour ambient in nanoporous membranes with the pore diameter of 80nm, thickness of 472nm, and three porosities of 0.25, 0.33 and 0.5 are numerically simulated. The numerical results indicate that the highest heat transfer coefficient is about 1740kW/m²·K; the highest heat flux is about 1.49kW/cm² with only about the wall superheat of 8.59K in the case of porosity equals to 0.5. The dissipated heat flux scaled with porosity because of the increasing effective evaporative area. Additionally, the self-regulation of the shape and curvature of the meniscus under different operating conditions is also observed. This work shows a promising approach to forecast the membrane performance for different geometry and working fluids.

Keywords: high heat flux, ultrathin nanoporous membrane, thin film evaporation, lattice Boltzmann method

Procedia PDF Downloads 149

Authors: Mohammad Javad Shariatzadeh, Dana Grecov

Abstract:

The tribological tests were performed on a new tribometer, in order to measure the coefficient of friction of a gland seal packing material on stainless steel shafts in presence of Cellulose Nanocrystal (CNC) suspension as a sustainable, environmentally friendly, water-based lubricant. To simulate the real situation from the slurry pumps, silica sands were used as slurry particles. The surface profiles after tests were measured by interferometer microscope to characterize the surface wear. Moreover, the coefficient of friction and surface wear were measured between stainless steel shaft and chrome steel ball to investigate the tribological effects of CNC in boundary lubrication region. Alignment of nanoparticles in the CNC suspensions are the main reason for friction and wear reduction. The homogeneous concentrated suspensions showed fingerprint patterns of a chiral nematic liquid crystal. These properties made CNC a very good lubricant additive in water.

Keywords: gland seal, lubricant additives, nanocrystalline cellulose, water-based lubricants

Procedia PDF Downloads 173

Authors: Ashwin Bala, K. Panthalaraja Kumaran, S. Prithviraj, R. Pradeep, J. Udhayakumar, S. Ajith

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In this paper, studies have been carried out for an in-house design of a waste heat recovery system for effectively utilizing the domestic air conditioner heat energy for producing hot water. Theoretical studies have been carried to optimizing the flow rate for getting maximum output with a minimum size of the heater. Critical diameter, wall thickness, and total length of the water pipeline have been estimated from the conventional heat transfer model. Several combinations of pipeline shapes viz., spiral, coil, zigzag wound through the radiator has been attempted and accordingly shape has been optimized using heat transfer analyses. The initial condition is declared based on the water flow rate and temperature. Through the parametric analytical studies we have conjectured that water flow rate, temperature difference between incoming water and radiator skin temperature, pipe material, radiator material, geometry of the water pipe viz., length, diameter, and wall thickness are having bearing on the lucrative design of a waste heat recovery system for air conditioners. Results generated through the numerical studies have been validated using an in-house waste heat recovery system for air conditioners.

Keywords: air conditioner design, energy conversion system, radiator design for energy recovery systems, waste heat recovery system

Procedia PDF Downloads 345

Authors: A. Bardey, P. James

Abstract:

With the rise of fast-fashion, over consumerism and overproduction, the fashion industry is believed to be one of the most polluting industry. It is a matter of importance today to further understand the factors involved in green consumerism to enhance sustainable fashion. One of the critical issues in also evaluating green consumerism, particularly in fashion, is the attitude-behaviour gap. Indeed, many consumers report a positive attitude towards sustainable fashion consumerism, but this attitude is not always actioned into behaviour. This study aims to further investigate the attitude-behaviour gap in sustainable fashion consumerism. S triangulation of qualitative and quantitative methods was used. Focus groups were used to gain opinions and understanding of the barriers to sustainable fashion consumption. A quantitative online questionnaire was then used to quantify the barriers identified in Study 1 and measure their influence on the attitude-behaviour gap. The results suggest that knowledge about sustainable fashion is the key factor in the attitude-behaviour gap in sustainable fashion consumerism. Accessibility was also identified as a factor, but this relationship is more complex. It is suggested that knowledge is the main factor in the attitude-behaviour gap and that once knowledge is controlled for, accessibility will become a main factor. The present study is the first one to identify the factors involved in sustainable fashion consumerism.

Keywords: fashion, consumer behaviour, sustainable consumerism, attitude-behavioural gap

Procedia PDF Downloads 168