Search results for: material handling equipment

Authors: Y. R. Adullayev, О. О. Karimzada

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Analytical expressions for inductances, current, ampere-turns, excitation winding, maximum width, coordinates of the levitation screen (LS) are derived for the calculation of electromagnetic devices based on tracking systems with levitation elements (TS with LS). Taking into account the expression of the complex magnetic resistance of the screen, the dependence of the screen width on the heating temperature of the physical and technical characteristics of the screen material and the relationship of the geometric dimensions of the magnetic circuit is established. Analytic expressions for a number of functional dependencies characterizing complex parameter relationships in explicit form are obtained and analyzed.

Keywords: tracking systems, levitation screens, electromagnetic levitation, excitation windings, magnetic cores, defining converter, receiving converter, electromagnetic force, electrical and magnetic resistance

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Authors: D. Korsacilar, C. Atas

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In this study, first thermoplastic composite materials/plates that have high ballistic impact resistance were produced. For this purpose, the thermoplastic prepreg and the vacuum bagging technique were used to produce a composite material. Thermoplastic prepregs (resin-impregnated fiber) that are supplied ready to be used, namely high-density polyethylene (HDPE) was chosen as matrix and unidirectional glass fiber was used as reinforcement. In order to compare the fiber configuration effect on mechanical properties, unidirectional and biaxial prepregs were used. Then the microstructural properties of the composites were investigated with scanning electron microscopy (SEM) analysis. Impact properties of the composites were examined by Charpy impact test and tensile mechanical tests and then the effects of ultraviolet irradiation were investigated on mechanical performance.

Keywords: ballistic, composite, thermoplastic, prepreg

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Authors: Muhammad Kashif Fida

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In the bank, teller’s job (cash officer) is highly important and critical as at one end it requires soft and brisk customer services and on the other side, handling cash with integrity. It is always challenging for recruiters to hire competent and trustworthy tellers. According to author’s knowledge, there is no comprehensive test available that may provide assistance in recruitment in Pakistan. So there is a dire need of a psychometric battery that could provide support in recruitment of potential candidates for the teller’ position. So, the aim of the present study was to construct ABL-Teller Aptitude Test (ABL-TApT). Three major phases have been designed by following American Psychological Association’s guidelines. The first phase was qualitative, indicators of the test have been explored by content analysis of the a) teller’s job descriptions (n=3), b) interview with senior tellers (n=6) and c) interview with HR personals (n=4). Content analysis of above yielded three border constructs; i). Personality, ii). Integrity/honesty, iii). Professional Work Aptitude. Identified indicators operationalized and statements (k=170) were generated using verbatim. It was then forwarded to the five experts for review of content validity. They finalized 156 items. In the second phase; ABL-TApT (k=156) administered on 323 participants through a computer application. The overall reliability of the test shows significant alpha coefficient (α=.81). Reliability of subscales have also significant alpha coefficients. Confirmatory Factor Analysis (CFA) performed to estimate the construct validity, confirms four main factors comprising of eight personality traits (Confidence, Organized, Compliance, Goal-oriented, Persistent, Forecasting, Patience, Caution), one Integrity/honesty factor, four factors of professional work aptitude (basic numerical ability and perceptual accuracy of letters, numbers and signature) and two factors for customer services (customer services, emotional maturity). Values of GFI, AGFI, NNFI, CFI, RFI and RMSEA are in recommended range depicting significant model fit. In third phase concurrent validity evidences have been pursued. Personality and integrity part of this scale has significant correlations with ‘conscientiousness’ factor of NEO-PI-R, reflecting strong concurrent validity. Customer services and emotional maturity have significant correlations with ‘Bar-On EQI’ showing another evidence of strong concurrent validity. It is concluded that ABL-TAPT is significantly reliable and valid battery of tests, will assist in objective recruitment of tellers and help recruiters in finding a more suitable human resource.

Keywords: concurrent validity, construct validity, content validity, reliability, teller aptitude test, objective recruitment

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Authors: Pakize Neslihan Taslı, Alev Cumbul, Gul Merve Yalcın, Fikrettin Sahin

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A key experimental trial in the regeneration of large oral and craniofacial defects is the neogenesis of osseous and ligamentous interfacial structures. Currently, oral regenerative medicine strategies are unpredictable for repair of tooth supporting tissues destroyed as a consequence of trauma, chronic infection or surgical resection. A different approach combining the gel-casting method with Hydroxy Apatite HA-based scaffold and different cell lineages as a hybrid system leads to successively mimic the early stage of tooth development, in vitro. HA is widely accepted as a bioactive material for guided bone and tooth regeneration. In this study, it was reported that, HA porous scaffold preparation, characterization and evaluation of structural and chemical properties. HA is the main factor that exists in tooth and it is in harmony with structural, biological, and mechanical characteristics. Here, this study shows mimicking immature tooth at the late bell stage design and construction of HA scaffolds for cell transplantation of human Adipose Stem Cells (hASCs), human Bone Marrow Stem Cells (hBMSCs) and Gingival Epitelial cells for the formation of human tooth dentin-pulp-enamel complexes in vitro. Scaffold characterization was demonstrated by SEM, FTIR and pore size and density measurements. The biological contraction of dental tissues against each other was demonstrated by mRNA gene expressions, histopatologic observations and protein release profile by ELISA tecnique. The tooth shaped constructs with a pore size ranging from 150 to 300 µm arranged by gathering right amounts of materials provide interconnected macro-porous structure. The newly formed tissue like structures that grow and integrate within the HA designed constructs forming tooth cementum like tissue, pulp and bone structures. These findings are important as they emphasize the potential biological effect of the hybrid scaffold system. In conclusion, this in vitro study clearly demonstrates that designed 3D scaffolds shaped as a immature tooth at the late bell stage were essential to form enamel-dentin-pulp interfaces with an appropriate cell and biodegradable material combination. The biomimetic architecture achieved here is providing a promising platform for dental tissue engineering.

Keywords: tooth regeneration, tissue engineering, adipose stem cells, hydroxyapatite tooth engineering, porous scaffold

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Authors: M. Hadji, A. Haddad, Y. Hadji

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The effects of boronizing treatment on the friction coefficient and wear behavior of Ti2AlC were investigated. In order to modify the surface properties of Ti2AlC, boronizing treatment was carried out through powder pack cementation in the 1150-1350 °C temperature range. After boronizing treatment, one mixture layer, composed of TiB2 and SiC, forms on the surface of Ti2AlC. The growth of the coating is processed by inward diffusion of Boron and obeys a linear rule. The Boronizing treatment increases the hardness of Ti2AlC from 6 GPa to 13GPa. In the pin-on-disc test, it was found that the material undergoes a steady-state coefficient of friction of around 0.8 and 0.45 in case of Ti2AlC/Al2O3 tribocouple under 7N load for the non treated and the boronized samples, respectively. The wear resistance of Ti2AlC under Al2O3 ball sliding has been significantly improved, which indicated that the boronizing treatment is a promising surface modification way of Ti2AlC.

Keywords: MAX phase, wear, hardness, boronizing

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Authors: R. Conde

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The Brazilian economic projections and social indicators show a future of crisis for the country. Solutions to avoid this crisis scenario are necessary. Several developed countries implement initiatives linked to sustainability, mainly related to the circular economy, to solve their crises quickly - green recovery. This article aims to assess social gains if Brazil followed the same recovery strategy. Furthermore, with the use of data presented and recognized in the international academic society, the number of jobs that can be created, if Brazil took the first steps towards a more circular economy, was found. Moreover, in addition to the gross value in the number of jobs created, this article also detailed the number of these jobs by type of activity (collection, processing, and manufacturing) and by type of material.

Keywords: circular economy, green recovery, job creation, social gains

Procedia PDF Downloads 134

Authors: Ivonete Teresinha Schulter Buss Heidemann, Michelle Kuntz Durand, Aline Megumi Arakawa-Belaunde, Sandra Mara Corrêa, Leandro Martins Costa Do Araujo, Kamila Soares Maciel

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Primary Health Care is defined as the level of a system of services that enables the achievement of answers to health needs. This level of care produces services and actions of attention to the person in the life cycle and in their health conditions or diseases. Primary Health Care refers to a conception of care model and organization of the health system that in Brazil seeks to reorganize the principles of the Unified Health System. This system is based on the principle of health as a citizen's right and duty of the State. Primary health care has family health as a priority strategy for its organization according to the precepts of the Unified Health System, structured in the logic of new sectoral practices, associating clinical work and health promotion. Thus, this study seeks to know the possibilities and limits of the care developed by professionals working in Primary Health Care. It was conducted by a qualitative approach of the participant action type, based on Paulo Freire's Research Itinerary, which corresponds to three moments: Thematic Investigation; Encoding and Decoding; and, Critical Unveiling. The themes were investigated in a health unit with the development of a culture circle with 20 professionals, from a municipality in southern Brazil, in the first half of 2021. The participants revealed as possibilities the involvement, bonding and strengthening of the interpersonal relationships of the professionals who work in the context of primary care. Promoting welcoming in primary care has favoured care and teamwork, as well as improved access. They also highlighted that care planning, the use of technologies in the process of communication and the orientation of the population enhances the levels of problem-solving capacity and the organization of services. As limits, the lack of professional recognition and the scarce material and human resources were revealed, conditions that generate tensions for health care. The reduction in the number of professionals and the low salary are pointed out as elements that boost the motivation of the health team for the development of the work. The participants revealed that due to COVID-19, the flow of care had as a priority the pandemic situation, which affected health care in primary care, and prevention and health promotion actions were canceled. The study demonstrated that empowerment and professional involvement are fundamental to promoting comprehensive and problem-solving care. However, limits of the teams are observed when exercising their activities, these are related to the lack of human and material resources, and the expansion of public health policies is urgent.

Keywords: health promotion, primary health care, health professionals, welcoming.

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Authors: Angelo Lerro, Manuela Battipede, Piero Gili, Alberto Brandl

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Redundancy requirements for UAV (Unmanned Aerial Vehicle) are hardly faced due to the generally restricted amount of available space and allowable weight for the aircraft systems, limiting their exploitation. Essential equipment as the Air Data, Attitude and Heading Reference Systems (ADAHRS) require several external probes to measure significant data as the Angle of Attack or the Sideslip Angle. Previous research focused on the analysis of a patented technology named Smart-ADAHRS (Smart Air Data, Attitude and Heading Reference System) as an alternative method to obtain reliable and accurate estimates of the aerodynamic angles. This solution is based on an innovative sensor fusion algorithm implementing soft computing techniques and it allows to obtain a simplified inertial and air data system reducing external devices. In fact, only one external source of dynamic and static pressures is needed. This paper focuses on the benefits which would be gained by the implementation of this system in UAV applications. A simplification of the entire ADAHRS architecture will bring to reduce the overall cost together with improved safety performance. Smart-ADAHRS has currently reached Technology Readiness Level (TRL) 6. Real flight tests took place on ultralight aircraft equipped with a suitable Flight Test Instrumentation (FTI). The output of the algorithm using the flight test measurements demonstrates the capability for this fusion algorithm to embed in a single device multiple physical and virtual sensors. Any source of dynamic and static pressure can be integrated with this system gaining a significant improvement in terms of versatility.

Keywords: aerodynamic angles, air data system, flight test, neural network, unmanned aerial vehicle, virtual sensor

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Authors: Rajnish Shrivastava, Y. R. Sood, Priti Pundir, Rahul Srivastava

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Power transformer is one of the most important devices that are used in power station. Due to several fault impending upon it or due to ageing, etc its life gets lowered. So, it becomes necessary to have diagnosis of oil for fault analysis. Due to the chemical, electrical, thermal and mechanical stress the insulating material in the power transformer degraded. It is important to regularly assess the condition of oil and the remaining life of the power transformer. In this paper UV-VIS absorption graph area is correlated with moisture content, Flash point, IFT and Density of Transformer oil. Since UV-VIS absorption graph area varies accordingly with the variation in different transformer parameters. So by obtaining the correlation among different oil parameters for oil with respect to UV-VIS absorption area, decay contents of transformer oil can be predicted

Keywords: breakdown voltage (BDV), interfacial Tension (IFT), moisture content, ultra violet-visible rays spectroscopy (UV-VIS)

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Authors: Musa Alhassan, Alhaji Mohammed Mustapha

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Review of studies carried out on the use of bagasse ash in the improvement of deficient soils in Nigeria, with emphasis on lateritic and black cotton soils is presented. Although, the bagasse ash is mostly used as additive to the conventional soil stabilizer (cement and lime), the studies generally showed improvement of geotechnical properties of the soils either modified or stabilized with the ash. This showed the potentials of using this agricultural waste (bagasse ash) in the improvement of geotechnical properties of deficient soils. Thus suggesting that using this material at large scale level, in geotechnical engineering practice could help in the provision of stable and durable structures, reduce cost of soil improvement and also reduces environmental nuisance caused by the unused waste in Nigeria

Keywords: bagasse ash, black cotton soil, deficient soil, laterite, soil improvement

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Authors: Ramezani M., Neitzert T.

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This paper investigates mechanical properties and formability of the AZ61 magnesium alloy at high temperatures. Tensile tests were performed at elevated temperatures of up to 400ºC. The results showed that as temperature increases, yield strength and ultimate tensile strength decrease significantly, while the material experiences an increase in ductility (maximum elongation before break). A finite element model has been developed to further investigate the formability of the AZ61 alloy by deep drawing a square cup. Effects of different process parameters such as punch and die geometry, forming speed and temperature as well as blank-holder force on deep drawability of the AZ61 alloy were studied and optimum values for these parameters are achieved which can be used as a design guide for deep drawing of this alloy.

Keywords: AZ61, formability, magnesium, mechanical properties

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Authors: Dial Tassadit Rania, Figueiredo De Oliveira Gabriel

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In this paper, we investigate the relationship between ports and their hinterland and foreland environments and the competitive relationship between the ports themselves. These two environments are changing, evolving and introducing new challenges for commercial and economic development at the regional, national and international levels. Because of the rise of the containerization phenomenon, shipping costs and port handling costs have considerably decreased due to economies of scale. The volume of maritime trade has increased substantially and the markets served by the ports have expanded. On these bases, overlapping hinterlands can give rise to the phenomenon of competition between ports. Our main contribution comparing to the existing literature on this issue, is to build a set of hinterland, foreland and competition indicators. Using these indicators? we investigate the effect of hinterland accessibility, foreland connectivity and inter-ports competition on containerized traffic of Europeans ports. For this, we have a 10-year panel database from 2004 to 2014. Our hinterland indicators are given by two indicators of accessibility; they describe the market potential of a port and are calculated using information on population and wealth (GDP). We then calculate population and wealth for different neighborhoods within a distance from a port ranging from 100 to 1000km. For the foreland, we produce two indicators: port connectivity and number of partners for each port. Finally, we compute the two indicators of inter-port competition and a market concentration indicator (Hirshmann-Herfindhal) for different neighborhood-distances around the port. We then apply a fixed-effect model to test the relationship above. Again, with a fixed effects model, we do a sensitivity analysis for each of these indicators to support the results obtained. The econometric results of the general model given by the regression of the accessibility indicators, the LSCI for port i, and the inter-port competition indicator on the containerized traffic of European ports show a positive and significant effect for accessibility to wealth and not to the population. The results are positive and significant for the two indicators of connectivity and competition as well. One of the main results of this research is that the port development given here by the increase of its containerized traffic is strongly related to the development of its hinterland and foreland environment. In addition, it is the market potential, given by the wealth of the hinterland that has an impact on the containerized traffic of a port. However, accessibility to a large population pool is not important for understanding the dynamics of containerized port traffic. Furthermore, in order to continue to develop, a port must penetrate its hinterland at a deep level exceeding 100 km around the port and seek markets beyond this perimeter. The port authorities could focus their marketing efforts on the immediate hinterland, which can, as the results shows, not be captive and thus engage new approaches of port governance to make it more attractive.

Keywords: accessibility, connectivity, European containerization, European hinterland and foreland, inter-port competition

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Authors: Somnath Karmakar, S. Chakraverty

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This work investigates the vibration of nonhomogeneous Timoshenko nanobeam resting on the Winkler-Pasternak foundation. Eringen’s nonlocal theory has been used to investigate small-scale effects. The Differential Quadrature method is used to obtain the frequency parameters with various classical boundary conditions. The nonhomogeneous beam model has been considered, where Young’s modulus and density of the beam material vary linearly and quadratically. Convergence of frequency parameters is also discussed. The influence of mechanical properties and scaling parameters on vibration frequencies are investigated for different boundary conditions.

Keywords: Timoshenko beam, Eringen's nonlocal theory, differential quadrature method, nonhomogeneous nanobeam

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Authors: Tao Qu, Chandra Prakash, Vikas Tomar

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The interfaces between organic and inorganic phases in natural materials have been shown to be a key factor contributing to their high performance. This work analyzes crack propagation in a 2-ply laminate subjected to uniaxial tensile mode-I crack propagation loading that has laminate properties derived based on biological material constituents (marine exoskeleton- chitin and calcite). Interfaces in such laminates are explicitly modeled based on earlier molecular simulations performed by authors. Extended finite element method and cohesive zone modeling based simulations coupled with theoretical analysis are used to analyze crack propagation. Analyses explicitly quantify the effect that interface mechanical property variation has on the delamination as well as the transverse crack propagation in examined 2-ply laminates.

Keywords: chitin, composites, interfaces, fracture

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Authors: Edoardo Schinco

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Studying the Marxist intellectual tradition, it is possible to verify that there were numerous cases of philosophical regression, in which the important achievements of detailed studies have been replaced by naïve ideas and previous misunderstandings: one of most important example of this tendency is related to the question of ideology. According to a common Enlightenment approach, the ideology is essentially not a reality, i.e., a factor capable of having an effect on the reality itself; in other words, the ideology is a mere error without specific historical meaning, which is only due to ignorance or inability of subjects to understand the truth. From this point of view, the consequent and immediate practice against every form of ideology are the rational dialogue, the reasoning based on common sense, in order to dispel the obscurity of ignorance through the light of pure reason. The limits of this philosophical orientation are however both theoretical and practical: on the one hand, the Enlightenment criticism of ideology is not an historicistic thought, since it cannot grasp the inner connection that ties an historical context and its peculiar ideology together; moreover, on the other hand, when the Enlightenment approach fails to release people from their illusions (e.g., when the ideology persists, despite the explanation of its illusoriness), it usually becomes a racist or elitarian thought. Unlike this first conception of ideology, Gramsci attempts to recover Marx’s original thought and to valorize its dialectical methodology with respect to the reality of ideology. As Marx suggests, the ideology – in negative meaning – is surely an error, a misleading knowledge, which aims to defense the current state of things and to conceal social, political or moral contradictions; but, that is precisely why the ideological error is not casual: every ideology mediately roots in a particular material context, from which it takes its reason being. Gramsci avoids, however, any mechanistic interpretation of Marx and, for this reason; he underlines the dialectic relation that exists between material base and ideological superstructure; in this way, a specific ideology is not only a passive product of base but also an active factor that reacts on the base itself and modifies it. Therefore, there is a considerable revaluation of ideology’s role in maintenance of status quo and the consequent thematization of both ideology as objective force, active in history, and ideology as cultural hegemony of ruling class on subordinate groups. Among the Marxists, the French philosopher Louis Althusser also gives his contribution to this crucial question; as follower of Gramsci’s thought, he develops the idea of ideology as an objective force through the notions of Repressive State Apparatus (RSA) and Ideological State Apparatuses (ISA). In addition to this, his philosophy is characterized by the presence of structuralist elements, which must be studied, since they deeply change the theoretical foundation of his Marxist thought.

Keywords: Althusser, enlightenment, Gramsci, ideology

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Authors: Hasan Husnu Korkmaz, Serra Zerrin Korkmaz

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Earthquakes are the natural disasters that threat several countries. Turkey is situated on a very active earthquake zone. During the recent earthquakes, thousands of people died due to failure of reinforced concrete structures. Although Turkey has a very sufficient earthquake code, the design and construction mistakes were repeated for old structures. Lack of the control mechanism during the construction process may be the most important reason of failure. The quality of the concrete and poor detailing of steel or reinforcement is the most important headings. In this paper, the reasons of failure of reinforced concrete structures were summarized with relevant photos. The paper is beneficial for civil engineers as well as architect who are in the process of construction and design of structures in earthquake zones.

Keywords: earthquake, reinforced concrete structure, failure, material

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Authors: Viktor R. Stoynov, Zlatka V. Valkova-Jarvis

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The intelligent management and optimisation of radio resource technologies will lead to a considerable improvement in the overall performance in Next Generation Networks (NGNs). Carrier Aggregation (CA) technology, also known as Spectrum Aggregation, enables more efficient use of the available spectrum by combining multiple Component Carriers (CCs) in a virtual wideband channel. LTE-A (Long Term Evolution–Advanced) CA technology can combine multiple adjacent or separate CCs in the same band or in different bands. In this way, increased data rates and dynamic load balancing can be achieved, resulting in a more reliable and efficient operation of mobile networks and the enabling of high bandwidth mobile services. In this paper, several distinct CA deployment strategies for the utilisation of spectrum bands are compared in indoor-outdoor scenarios, simulated via the recently-developed Realistic Indoor Environment Generator (RIEG). We analyse the performance of the User Equipment (UE) by integrating the average throughput, the level of fairness of radio resource allocation, and other parameters, into one summative assessment termed a Comparative Factor (CF). In addition, comparison of non-CA and CA indoor mobile networks is carried out under different load conditions: varying numbers and positions of UEs. The experimental results demonstrate that the CA technology can improve network performance, especially in the case of indoor scenarios. Additionally, we show that an increase of carrier frequency does not necessarily lead to improved CF values, due to high wall-penetration losses. The performance of users under bad-channel conditions, often located in the periphery of the cells, can be improved by intelligent CA location. Furthermore, a combination of such a deployment and effective radio resource allocation management with respect to user-fairness plays a crucial role in improving the performance of LTE-A networks.

Keywords: comparative factor, carrier aggregation, indoor mobile network, resource allocation

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Authors: Abdelsalam Elawwad, Mostafa Ragab, Hisham Abdel-Halim

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Leakage in sewerage system can cause groundwater and soil contamination in urban areas, especially in area with a high groundwater table. This is a serious problem in small villages in developing countries that rely on ground water as a source for irrigation and drinking purposes. In the developed countries, the recent trend in areas with low population densities is vacuum sewerage system, which is environmentally safer than conventional gravity system, protecting public health, preventing exfiltration to the ground water, very easily applied in a relatively short time and can cope with a faster expansion of the urbanized areas. The aim of this work is to assess the feasibility of using vacuum sewerage in developing country, such as Egypt. Knowledge of local conditions can determine the most suitable sewer system for a specific region. Technical, environmental and financial comparisons between conventional sewerage system and vacuum sewerage system were held using statistical analysis. Different conditions, such as population densities, geometry of area, and ground water depths were evaluated. Sample comprising of 30 Egyptian villages was selected, where a complete design for conventional sewerage system and vacuum sewerage system was done. Based on this study, it is recommended from the environmental point of view to construct the vacuum sewerage system in such villages with low population densities; however, it is not economic for all cases. From financial point of view, vacuum sewerage system was a good competitor to conventional systems in flat areas and areas with high groundwater table. The local market supplying of the construction equipment especially collection chambers will greatly affect the investment cost. Capacity building and social mobilization will also play a great role in sustainability of this system. At the end, it is noteworthy that environmental sustainability and public health are more important than the financial aspects.

Keywords: ground water, conventional system, vacuum system, statistics, cost, density, terrain

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Authors: S. M. Mabandla, P. Loveday, C. Gomes, D. T. Maiga, T. T. Phadi

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Lead zirconate titanate (PZT) piezoelectric ceramics are widely used in ultrasonic applications due to their ability to effectively convert electrical energy into mechanical vibrations and vice versa. This paper presents a study on the behaviour of various combinations of pairs of PZT piezoelectric ceramic materials positioned adjacent to each other with an intermediate gap submerged in water, where one piezoelectric ceramic material is excited by a cyclic electric field with constant frequency and amplitude displacement. The transmitted ultrasonic sound propagates through the medium and is received by the PZT ceramic at the other end, the ultrasonic sound signal amplitude displacement experiences attenuation during propagation due to acoustic impedance. The investigation focuses on understanding the causes of extremely high amplitude displacement attenuation that have been observed in various combinations of piezoelectric ceramic pairs that are submerged in water arranged in a manner stipulated earlier. by examining various combinations of pairs of these piezoelectric ceramics, their physical, electrical, and acoustic properties, and behaviour and attributing them to the observed significant signal attenuation. The experimental setup involves exciting one piezoelectric ceramic material at one end with a burst square cyclic electric field signal of constant frequency, which generates a burst of ultrasonic sound that propagates through the water medium to the adjacent piezoelectric ceramic at the other end. Mechanical vibrations of a PZT piezoelectric ceramic are measured using a double-beam laser Doppler vibrometer to mimic the incident ultrasonic waves generated and received ultrasonic waves on the other end due to mechanical vibrations of a PZT. The measured ultrasonic sound wave signals are continuously compared to the applied cyclic electric field at both ends. The impedance matching networks are continuously tuned at both ends to eliminate electromechanical impedance mismatch to improve ultrasonic transmission and reception. The study delves into various physical, electrical, and acoustic properties of the PZT piezoelectric ceramics, such as the electromechanical coupling factor, acoustic coupling, and elasticity, among others. These properties are analyzed to identify potential factors contributing to the unusually high acoustic impedance in the water medium between the ceramics. Additionally, impedance-matching networks are investigated at both ends to offset the high signal attenuation and improve overall system performance. The findings will be reported in this paper.

Keywords: acoustic impedance, impedance mismatch, piezoelectric ceramics, ultrasonic sound

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Authors: Pedro G. Morouço

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One utmost challenge in Tissue Engineering is the production of 3D constructs capable of mimicking the functional hierarchy of native tissues. This is well stated for osteochondral tissue due to the complex mechanical functional unit based on the junction of articular cartilage and bone. Thus, the aim of the present study was to develop a new additive manufacturing system coupling micro-extrusion with hydrogels printing. An integrated system was developed with 2 main features: (i) the printing of up to three distinct hydrogels; (ii) in coordination with the printing of a thermoplastic structural support. The hydrogel printing module was projected with a ‘revolver-like’ system, where the hydrogel selection was made by a rotating mechanism. The hydrogel deposition was then controlled by pressured air input. The use of specific components approved for medical use was incorporated in the material dispensing system (Nordson EDF Optimum® fluid dispensing system). The thermoplastic extrusion modulus enabled the control of required extrusion temperature through electric resistances in the polymer reservoir and the extrusion system. After testing and upgrades, a hydrogel modulus with 3 syringes (3cm3 capacity each), with a pressure range of 0-2.5bar, a rotational speed of 0-5rpm, and working with needles from 200-800µm was obtained. This modulus was successfully coupled to the extrusion system that presented a temperature up to 300˚C, a pressure range of 0-12bar, and working with nozzles from 200-500µm. The applied motor could provide a velocity range 0-2000mm/min. Although, there are distinct printing requirements for hydrogels and polymers, the novel system could develop hybrid scaffolds, combining the 2 moduli. The morphological analysis showed high reliability (n=5) between the theoretical and obtained filament and pore size (350µm and 300µm vs. 342±4µm and 302±3µm, p>0.05, respectively) of the polymer; and multi-material 3D constructs were successfully obtained. Human tissues present very distinct and complex structures regarding their mechanical properties, organization, composition and dimensions. For osteochondral regenerative medicine, a multiphasic scaffold is required as subchondral bone and overlying cartilage must regenerate at the same time. Thus, a scaffold with 3 layers (bone, intermediate and cartilage parts) can be a promising approach. The developed system may give a suitable solution to construct those hybrid scaffolds with enhanced properties. The present novel system is a step-forward regarding osteochondral tissue engineering due to its ability to generate layered mechanically stable implants through the double-printing of hydrogels with thermoplastics.

Keywords: 3D bioprinting, bone regeneration, cartilage regeneration, regenerative medicine, tissue engineering

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Authors: Naava Dihi, Jon Anson

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Love, so it appears, is not socially blind. We show that partner selection is socially constrained, and the freedom to choose is limited by at least two major factors or capitals: on the one hand, material resources and education, locating the partners on a scale of personal achievement and economic independence. On the other, the partners' ascriptive belonging to particular ethnic, or origin, groups, differentiated by the groups' social prestige, as well as by their culture, history and even physical characteristics. However, the relative importance of achievement and ascriptive factors, as well as the overlap between them, varies from society to society, depending on the society's structure and the factors shaping it. Israeli social structure has been shaped by the waves of new immigrants who arrived over the years. The timing of their arrival, their patterns of physical settlement and their occupational inclusion or exclusion have together created a mosaic of social groups whose principal common feature has been the country of origin from which they arrived. The analysis of marriage patterns helps illuminate the social meanings of the groups and their borders. To the extent that ethnic group membership has meaning for individuals and influences their life choices, the ascriptive factor will gain in importance relative to the achievement factor in their choice of marriage partner. In this research, we examine Jewish Israeli marriage patterns by looking at the marriage choices of 5,041 women aged 15 to 49 who were single at the census in 1983, and who were married at the time of the 1995 census, 12 years later. The database for this study was a file linking respondents from the 1983 and the 1995 censuses. In both cases, 5 percent of household were randomly chosen, so that our sample includes about 4 percent of women in Israel in 1983. We present three basic analyses: (1) Who was still single in 1983, using personal and household data from the 1983 census (binomial model), (2) Who married between 1983 and a1995, using personal and household data from the 1983 census (binomial model), (3) What were the personal characteristics of the womens’ partners in 1995, using data from the 1995 census (loglinear model). We show (i) that material and cultural capital both operate to delay marriage and to increase the probability of remaining single; and (ii) while there is a clear association between ethnic group membership and education, endogamy and homogamy both operate as separate forces which constraint (but do not determine) the choice of marriage partner, and thus both serve to reproduce the current pattern of relationships, as well as identifying patterns of proximity and distance between the different groups.

Keywords: Israel, nuptiality, ascription, achievement

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Authors: Cheng-Chi Yu, Yu-Shiue Wang, Kei-Lin Kuo

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Active Independent Front Steering system is a steering system which can according to vehicle driving situation adjusts the relation of steering angle between inner wheel and outer wheel. In low-speed cornering, AIFS sets the steering angles of inner and outer wheel into Ackerman steering geometry to make vehicle has less cornering radius. Besides, AIFS changes the steering geometry to parallel or even anti-Ackerman steering geometry to keep vehicle stability in high-speed cornering. Therefore, based on the analysis of the vehicle steering behavior from different steering geometries, this study develops a new screw type of active independent front steering system to make vehicles best cornering performance at any speeds. The screw type of active independent front steering system keeps the pinion and separates the rack into main rack and second rack. Two racks connect by a screw. Extra screw rotated motion powered by assistant motor through coupler makes second rack move relative to main rack, which can adjust both steering ratio and steering geometry. First of all, this study distinguishes the steering geometry by using Ackerman percentage and utilizes the software of ADAMS/Car to construct diverse steering geometry models. The different steering geometries are compared at low-speed and high-speed cornering, and then control strategies of the active independent front steering systems could be formulated. Secondly, this study applies closed loop equation to analyze tire steering angles and carries out optimization calculations to make the steering geometry from traditional rack and pinion steering system near to Ackerman steering geometry. Steering characteristics of the optimum steering mechanism and motion characteristics of vehicle installed the steering mechanism are verified by ADAMS/Car models of front suspension and full vehicle respectively. By adding dual auxiliary rack and dual motor to the optimum steering mechanism, the active independent front steering system could be developed to achieve the functions of variable steering ratio and variable steering geometry. At last, this study uses ADAMS/Car and Matlab/Simulink to co-simulate the cornering motion of vehicles confirms the vehicle installed the Active Independent Front Steering (AIFS) system has better handling performance than that with Active Independent Steering (AFS) system or with Electric Power Steering (EPS) system. At low-speed cornering, the vehicles with AIFS system and with AFS system have better maneuverability, less cornering radius, than the traditional vehicle with EPS system because that AIFS and AFS systems both provide function of variable steering ratio. However, there is a slight penalty in the motor(s) power consumption. In addition, because of the capability of variable steering geometry, the vehicle with AIFS system has better high-speed cornering stability, trajectory keeping, and even less motor(s) power consumption than that with EPS system and also with AFS system.

Keywords: active front steering system, active independent front steering system, steering geometry, steering ratio

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Authors: Thierry Sammour Sawaya, Heikki Deschacht

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In commercial aircraft operations, almost half of the accidents happen during approach or landing phases. Automatic guidance and automatic landings have proven to bring significant safety value added for this challenging landing phase. This is why Airbus and ScioTeq have decided to work together to explore the capability of image-based landing solutions as additional landing aids to further expand the possibility to perform automatic approach and landing to runways where the current guiding systems are either not fitted or not optimum. Current systems for automated landing often depend on radio signals provided by airport ground infrastructure on the airport or satellite coverage. In addition, these radio signals may not always be available with the integrity and performance required for safe automatic landing. Being independent from these radio signals would widen the operations possibilities and increase the number of automated landings. Airbus and ScioTeq are joining their expertise in the field of Computer Vision in the European Program called Clean Sky 2 Large Passenger Aircraft, in which they are leading the IMBALS (IMage BAsed Landing Solutions) project. The ultimate goal of this project is to demonstrate, develop, validate and verify a certifiable automatic landing system guiding an airplane during the approach and landing phases based on an onboard camera system capturing images, enabling automatic landing independent from radio signals and without precision instrument for landing. In the frame of this project, ScioTeq is responsible for the development of the Image Processing Platform (IPP), while Airbus is responsible for defining the functional and system requirements as well as the testing and integration of the developed equipment in a Large Passenger Aircraft representative environment. The aim of this paper will be to describe the system as well as the associated methods and tools developed for validation and verification.

Keywords: aircraft landing system, aircraft safety, autoland, avionic system, computer vision, image processing

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Authors: Daniel F. Bohorquez, Luis M. Agudelo, Henry H. León

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Heart rate variability (HRV) is defined as the temporary variation between heartbeats or RR intervals (distance between R waves in an electrocardiographic signal). This distance is currently a recognized biomarker. With the analysis of the distance, it is possible to assess the sympathetic and parasympathetic nervous systems. These systems are responsible for the regulation of the cardiac muscle. The analysis allows health specialists and researchers to diagnose various pathologies based on this variation. For the acquisition and analysis of HRV taken from a cardiac electrical signal, electronic equipment and analysis software that work independently are currently used. This complicates and delays the process of interpretation and diagnosis. With this delay, the health condition of patients can be put at greater risk. This can lead to an untimely treatment. This document presents a single portable device capable of acquiring electrocardiographic signals and calculating a total of 19 HRV metrics. This reduces the time required, resulting in a timelier intervention. The device has an electrocardiographic signal acquisition card attached to a microcontroller capable of transmitting the cardiac signal wirelessly to a mobile device. In addition, a mobile application was designed to analyze the cardiac waveform. The device calculates the RR and different metrics. The application allows a user to visualize in real-time the cardiac signal and the 19 metrics. The information is exported to a cloud database for remote analysis. The study was performed under controlled conditions in the simulated hospital of the Universidad de la Sabana, Colombia. A total of 60 signals were acquired and analyzed. The device was compared against two reference systems. The results show a strong level of correlation (r > 0.95, p < 0.05) between the 19 metrics compared. Therefore, the use of the portable system evaluated in clinical scenarios controlled by medical specialists and researchers is recommended for the evaluation of the condition of the cardiac system.

Keywords: biological signal análisis, heart rate variability (HRV), HRV metrics, mobile app, portable device.

Procedia PDF Downloads 173

Authors: Bekir Mugayitoglu

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This work shares pre-service teachers' experiences with the Book Creator application during the face-to-face class. Participants for this work were pre-service teachers in a semester-long instructional technology course who developed their own e-books. The work was conducted during the Fall of 2023. Eleven pre-service teachers completed the project, producing books appropriate to their area of concentration. Analysis of participant progress reports shows, that Exemplars showcase creative ways to prepare pre-service teachers to design their own books and have an opportunity to use mobile apps to create a variety of e-material options. The findings support future opportunities for pre-service teachers to design and implement technology-supported literacy applications to integrate into their own classroom pedagogy.

Keywords: scaffolding, e-book, classroom pedagogy, face-to-face class

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Authors: Ali Saeed Alghamdi, Basel Mazen Alsolami, Basel Saeed Alghamdi, Muhanad Saleh Alzahrani Alamri, Salman Anwar Thabet, Abdulhalim J. Kinsara

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Objectives: This study measures the knowledge of the cardiovascular disease among the general population in western regions of Saudi Arabia, and it aimed to increase the level of awareness about cardiovascular diseases among the general population by providing an awareness lecture that included information about the risk factors, major symptoms, and prevention of cardiovascular diseases. The lecture has been attached at the end of the questionnaire. Setting: This study was conducted through an online questionnaire that included our aim and main objectives that targeted the general population in the Western regions of Saudi Arabia (Makkah and Madinah regions). Participants: This study participants were 460 collected through an online questionnaire. Methods: All Saudi citizens and residents who live in the western region of Saudi Arabia aged 18 years and above will be invited to participate voluntarily. A pre-structured questionnaire was designed to collect data on age, gender, marital status, education level, occupation, lifestyle habits, and history of heart diseases, with cardiac symptoms and risk factors sections. Results: The majority of respondents were females (74.8%) and Saudis. The knowledge about cardiovascular disease risk factors was weak. Only (18.5%) scores an excellent response regarding risk factors awareness. Lack of exercise, stress, and obesity were the most known risk factors. Regarding cardiovascular disease symptoms, chest pain scores the highest symptom (87.6%) among other symptoms like dyspnea, syncope, and excessive sweating. Participants revealed a poor awareness regarding cardiovascular disease symptoms also (0.9%). However, preventable factors for cardiovascular diseases were more knowledgeable than others categories in this study (60% fall into excellent knowledge). Smoking cessation, normal cholesterol level, and normal blood pressure score the highest preventable methods (92.2%), (88.6%), and (78.7%) respectively. 83.7% of the participant have attended the awareness lecture, and 99 of the attendees reported that the lecture increased their knowledge about cardiovascular disease. Conclusion: This study discussed the level of community awareness of cardiovascular disease in terms of symptoms, risk factors, and protective factors. We found a huge lack of the participant's level of knowledge about the disease and how to prevent it. Moreover, we measure the prevalence of the comorbidities among our participants (diabetes, hypertension, hypercholesterolemia/ hypertriglyceridemia) and their extent of adherence to their medication. In conclusion, this study not only demonstrates awareness of cardiovascular disease risk factors, symptoms, management, and the association between each domain but also provides educational material. Further educational material and campaigns are required to increase awareness and knowledge about cardiovascular diseases.

Keywords: awareness, cardiovascular diseases, education, prevention, risk factors

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Authors: Shiva Abdoli, Daniel T.Semere

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Several researches have been conducted to study consumption of energy in cutting process. Most of these researches are focusing to measure the consumption and propose consumption reduction methods. In this work, the relation between the cutting parameters and the consumption is investigated in order to establish a generalized energy consumption model that can be used for process and production planning in real production lines. Using the generalized model, the process planning will be carried out by taking into account the energy as a function of the selected process parameters. Similarly, the generalized model can be used in production planning to select the right operational parameters like batch sizes, routing, buffer size, etc. in a production line. The description and derivation of the model as well as a case study are given in this paper to illustrate the applicability and validity of the model.

Keywords: process parameters, cutting process, energy efficiency, Material Removal Rate (MRR)

Procedia PDF Downloads 483

Authors: Lori L. Scarlatos, Ryan Courtney

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This paper explores the impact that playing a casual game can have on a player's learning and subsequent behavior. A casual mobile game, Container Chaos, was created to teach undergraduate students about the carbon footprint of various disposable beverage containers. Learning was tested with a short quiz, and behavior was tested by observing which beverage containers players choose when offered a drink and a snack. The game was tested multiple times, under a variety of different circumstances. Findings of these tests indicate that, with extended play over time, players can learn new information and sometimes even change their behavior as a result. This has implications for how other casual games can be used to teach concepts and possibly modify behavior.

Keywords: behavior, carbon footprint, casual games, environmental impact, material sciences

Procedia PDF Downloads 139

Authors: Ahmed El Naggar, Homyan Saleh

Abstract:

Dams are crucial for flood control, water supply, and the creation of hydroelectric power. Every dam has a water conveyance system, such as a spillway, providing the safe discharge of catastrophic floods when necessary. Spillway design has historically been investigated in laboratory research owing to the absence of suitable full-scale flow monitoring equipment and safety problems. Prototype measurements of aerated flows are urgently needed to quantify projected scale effects and provide missing validation data for design guidelines and numerical simulations. In this work, an image-based investigation of free-surface flows on a tiered spillway was undertaken at the laboratory (fixed camera installation) and prototype size (drone video) (drone footage) (drone footage). The drone videos were generated using data from citizen science. Analyses permitted the measurement of the free-surface aeration inception point, air-water surface velocities, fluctuations, and residual energy at the chute's downstream end from a remote site. The prototype observations offered full-scale proof of concept, while laboratory results were efficiently confirmed against invasive phase-detection probe data. This paper stresses the efficacy of image-based analyses at prototype spillways. It highlights how citizen science data may enable academics better understand real-world air-water flow dynamics and offers a framework for a small collection of long-missing prototype data.

Keywords: remote sensing, aerated flows, large dams, proof of concept, dam spillways, air-water flows, prototype operation, remote sensing, inception point, optical flow, turbulence, residual energy

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Authors: Amgad Rezk, Heba Ahmed, Leslie Yeo

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Ultrasound presents a powerful means for material synthesis. In this talk, we showcase a new field demonstrating the possibility for harnessing sound energy sources at considerably higher frequencies (10 MHz to 1 GHz) compared to conventional ultrasound (kHz and up to ~2 MHz) for crystalising and manipulating a variety of nanoscale materials. At these frequencies, cavitation—which underpins most sonochemical processes—is largely absent, suggesting that altogether fundamentally different mechanisms are at dominant. Examples include the crystallization of highly oriented structures, quasi-2D metal-organic frameworks and nanocomposites. These fascinating examples reveal how the highly nonlinear electromechanical coupling associated with high-frequency surface vibration gives rise to molecular ordering and assembly on the nano and microscale.

Keywords: high-frequency acoustics, microfluidics, crystallisation, composite nanomaterials

Procedia PDF Downloads 106