Search results for: contact voltage

Authors: Vixen Joshua Tan, Siyuan He

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Scanners have been implemented within single point laser rangefinders, to determine the ranges within an environment by sweeping the laser spot across the surface of interest. The research motivation is to exploit a smaller and cheaper alternative scanning component for the emitting portion within current designs of laser rangefinders. This research implements an FPCB (Flexible Programmable Circuit Board) Electromagnetic 1-Dimensional scanning micro-mirror as a scanning component for laser rangefinding by means of triangulation. The prototype uses a laser module, micro-mirror, and receiver. The laser module is infrared (850 nm) with a power output of 4.5 mW. The receiver consists of a 50 mm convex lens and a 45mm 1-dimensional PSD (Position Sensitive Detector) placed at the focal length of the lens at 50 mm. The scanning component is an elliptical Micro-Mirror attached onto an FPCB Structure. The FPCB structure has two miniature magnets placed symmetrically underneath it on either side, which are then electromagnetically actuated by small solenoids, causing the FPCB to mechanically rotate about its torsion beams. The laser module projects a laser spot onto the micro-mirror surface, hence producing a scanning motion of the laser spot during the rotational actuation of the FPCB. The receiver is placed at a fixed distance from the micro-mirror scanner and is oriented to capture the scanning motion of the laser spot during operation. The elliptical aperture dimensions of the micro-mirror are 8mm by 5.5 mm. The micro-mirror is supported by an FPCB with two torsion beams with dimensions of 4mm by 0.5mm. The overall length of the FPCB is 23 mm. The voltage supplied to the solenoids is sinusoidal with an amplitude of 3.5 volts and 4.5 volts to achieve optical scanning angles of +/- 10 and +/- 17 degrees respectively. The operating scanning frequency during experiments was 5 Hz. For an optical angle of +/- 10 degrees, the prototype is capable of detecting objects within the ranges from 0.3-1.2 meters with an error of less than 15%. As for an optical angle of +/- 17 degrees the measuring range was from 0.3-0.7 meters with an error of 16% or less. Discrepancy between the experimental and actual data is possibly caused by misalignment of the components during experiments. Furthermore, the power of the laser spot collected by the receiver gradually decreased as the object was placed further from the sensor. A higher powered laser will be tested to potentially measure further distances more accurately. Moreover, a wide-angled lens will be used in future experiments when higher scanning angles are used. Modulation within the current and future higher powered lasers will be implemented to enable the operation of the laser rangefinder prototype without the use of safety goggles.

Keywords: FPCB electromagnetic 1-D scanning micro-mirror, laser rangefinder, position sensitive detector, PSD, triangulation

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Authors: Vanda Ferreira Ribeiro, Daiane Tomacheski, Douglas Naue Simões, Michele Pitto, Ruth Marlene Campomanes Santana

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Indoor environments, such as car cabins and public transportation vehicles are places where users are subject to air quality. Microorganisms (bacteria, fungi, yeasts) enter these environments through windows, ventilation systems and may use the organic particles present as a growth substrate. In addition, atmospheric pollutants can act as potential carbon and nitrogen sources for some microorganisms. Compounds base SEBS copolymers, poly(styrene-b-(ethylene-co-butylene)-b-styrene, are a class of thermoplastic elastomers (TPEs), fully recyclable and largely used in automotive parts. Metals, such as cooper and silver, have biocidal activities and the production of the SEBS compounds by melting blending with these agents can be a good option for producing compounds for use in plastic parts of ventilation systems and automotive air-conditioning, in order to minimize the problems caused by growth of pathogenic microorganisms. In this sense, the aim of this work was to evaluate the effect of copper microparticles as antimicrobial agent in compositions based on SEBS/PP/oil/calcite. Copper microparticles were used in weight proportion of 0%, 1%, 2% and 4%. The compounds were prepared using a co-rotating double screw extruder (L/D ratio of 40/1 and 16 mm screw diameter). The processing parameters were 300 rpm of screw rotation rate, with a temperature profile between 150 to 190°C. SEBS based TPE compounds were injection molded. The compounds emission were characterized by gravimetric fogging test. Compounds were characterized by physical (density and staining by contact), mechanical (hardness and tension properties) and rheological properties (melt volume rate – MVR). Antibacterial properties were evaluated against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) strains. To avaluate the abilities toward the fungi have been chosen Aspergillus niger (A. niger), Candida albicans (C. albicans), Cladosporium cladosporioides (C. cladosporioides) and Penicillium chrysogenum (P. chrysogenum). The results of biological tests showed a reduction on bacteria in up to 88% in E.coli and up to 93% in S. aureus. The tests with fungi showed no conclusive results because the sample without copper also demonstrated inhibition of the development of these microorganisms. The copper addition did not cause significant variations in mechanical properties, in the MVR and the emission behavior of the compounds. The density increases with the increment of copper in compounds.

Keywords: air conditioner, antimicrobial, cooper, SEBS

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Authors: Kauser Jahan, Jason Halvorsen, Kara Banks, Kara Natoli, Elizabeth McWeeney, Brittany LeMasney, Nicole Caramanna, Justin Hillman, Christopher Hauske, Meghan Sparks

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The Virtual Engineers on Wheels (ViEW) is a revised version of our established mobile K-12 outreach program Engineers on Wheels in order to address the pandemic. The Virtual Engineers on Wheels' (VIEW) goal has stayed the same as in prior years: to provide K-12 students and educators with the necessary resources to peak interest in the expanding fields of engineering. With these trying times, the Virtual Engineers on Wheels outreach has adapted its medium of instruction to be more seamless with the online approach to teaching and outreach. In the midst of COVID-19, providing a safe transfer of information has become a constraint for research. The focus has become how to uphold a level of quality instruction without diminishing the safety of those involved by promoting proper health practices and giving hope to students as well as their families. Furthermore, ViEW has created resources on effective strategies that minimize risk factors of COVID-19 and inform families that there is still a promising future ahead. To obtain these goals while still maintaining true to the hands-on learning that is so crucial to young minds, the approach is online video lectures followed by experiments within different engineering disciplines. ViEW has created a comprehensive website that students can leverage to explore the different fields of study. One of the experiments entails teaching about drone usage and how it might play a factor in the future of unmanned deliveries. Some of the other experiments focus on the differences in mask materials and their effectiveness, as well as their environmental outlook. Having students perform from home enables them a safe environment to learn at their own pace while still providing quality instruction that would normally be achieved in the classroom. Contact information is readily available on the website to provide interested parties with a means to ask their inquiries. As it currently stands, the interest in engineering/STEM-related fields is underrepresented from women and certain minority groups. So alongside the desire to grow interest, helping balance the scales is one of the main priorities of VIEW. In previous years, VIEW surveyed students before and after instruction to see if their perception of engineering has changed. In general, it is the understanding that being exposed to engineering/STEM at a young age increases the chances that it will be pursued later in life.

Keywords: STEM, engineering outreach, teaching pedagogy, pandemic

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Authors: Harini Atturu, Divyani Byagari, Bindhu Rani Thumkunta, Sahitya Bammidi, Manasa Badveli

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Introduction: Biological, psychological and social domains influence the outcomes of pregnancy. The COVID19 pandemic had a significant effect on the psychological and social domains of pregnant women all over the world. Everyone has inherent coping mechanisms which ultimately determine the actual impact of such external stimulus on outcomes of pregnancy. This study aims to understand the coping strategies used by pregnant women to overcome the psychological impact of the first wave of the COVID 19 pandemic. Methods: Institutional ethics permission was sought. All pregnant women attending antenatal clinics in the institution during September 2020 were included in the study. Brief-COPE, a self-rated questionnaire, was provided to understand the coping strategies used by them. The Questionnaire consists of 28 questions that fall into 14 themes. These 14 themes were mapped into four domains consisting of Approaching coping (APC) styles, Avoidant Coping (AVC) styles, Humor and Religion. The results were analyzed using univariate and multivariate analysis. Factor analysis was performed to identify themes that are most frequently used. Results: 162 pregnant women were included in the study. The majority of the women were aged between 18 and 30 (90.1%). 60.9% of the respondents were having their first pregnancy and were in the 2nd trimester (59.6%). The majority of them were living in the city (74%), belonged to the middle class (77.6%) and were not working (70.1%). 56 respondents (34.6%) reported that they had contact with suspected or Covid positive patients. Many were worried that their pregnancy might be complicated (43%), their baby may contract COVID (45%) and their family members could get COVID during the hospital visits for antenatal check-ups. 33.6% of women admitted missing their regular antenatal check-ups because of the above concerns. All respondents used various coping strategies to overcome the psychological impact of COVID 19. Out of the 4 coping strategies, participants scored high on Religion with a mean of 5.471.45 followed by Approaching Coping (APC) styles (5.131.25), Humor (4.592.07) and Avoidant Coping (AVC) styles (4.130.88). Religion as a coping strategy scored high for all respondents irrespective of age, parity, trimester, social and employment status. Exploratory Factor analysis revealed two cluster groups that explained 68% of the variance, with Component 1 contributing to 58.9% and component 2 contributing 9.13% of the variance. Humor, Acceptance, Planning, and Religion were the top 4 factors that showed strong loadings. Conclusion: Most of the pregnant women were worried about the negative impact of COVID 19 on the outcomes of their pregnancy. Religion and Approaching coping styles seem to be the predominant coping strategies used by them. Interventionists and policymakers should consider these factors while providing support to such women.

Keywords: coping strategies, pregnancy, COVID-19, brief-COPE

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Authors: Kaushal Kishore, Suman Mukhopadhyay, Susovan Das, Manashi Adhikary, Sandip Bhattacharyya

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In integrated steel plants, conveyor belts are widely used for transferring raw materials from one location to another. An output pin bush coupling attached with a conveyor transferring iron ore fines and fluxes failed after two years of service life. This led to an operational delay of approximately 15 hours. This study is focused on failure analysis of the coupling and recommending counter-measures to prevent any such failures in the future. Investigation consisted of careful visual observation, checking of operating parameters, stress calculation and analysis, macro and micro-fractography, material characterizations like chemical and metallurgical analysis and tensile and impact testings. The fracture occurred from an unusually sharp double step. There were multiple corrosion pits near the step that aggravated the situation. Inner contact surface of the coupling revealed differential abrasion that created a macroscopic difference in the height of the component. This pointed towards misalignment of the coupling beyond a threshold limit. In addition to these design and installation issues, material of the coupling did not meet the quality standards. These were made up of grey cast iron having graphite morphology intermediate between random distribution (Type A) and rosette pattern (Type B). This manifested as a marked reduction in impact toughness and tensile strength of the component. These findings corroborated well with the brittle mode of fracture that might have occurred during minor impact loading while loading of conveyor belt with raw materials from height. Simulated study was conducted to examine the effect of corrosion pits on tensile and impact toughness of grey cast iron. It was observed that pitting marginally reduced tensile strength and ductility. However, there was marked (up to 45%) reduction in impact toughness due to pitting. Thus, it became evident that failure of the coupling occurred due to combination of factors like inferior material, misalignment, poor step design and corrosion pitting. Recommendation for life enhancement of coupling included the use of tougher SG 500/7 grade, incorporation of proper fillet radius for the step, correction of alignment and application of corrosion resistant organic coating to prevent pitting.

Keywords: brittle fracture, cast iron, coupling, double step, pitting, simulated impact tests

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Authors: Nabat Gojaeva, Mikayil Naghiyev, Sultan Jafarov, Gular Mikayilova

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Chovdar ore area is located in the contact of Dashkesan caldera and Shamkir horst-graben uplift, which comprises the central part of Lok-Karabakh Island arcs of South Caucasus metallogenic province in terms of regional tectonics. One of the main structural features of formation of the Mereh and Aghyokhush group of low sulfidation epithermal gold deposits, locating in the north peripheric part of the ore area, is involving the crossing areas of ore-hosting and ore-forming Pan-Caucasian-direction structurally-compound faults with the meridional, rhombically shaped faults. In addition, another significant feature is the temporally two- or three-stage ore formation. In the first stage -an early phase of Upper Bathonian age, sulfides are the dominant minerals, in the second stage- late ‘productive’ phase of Upper Bathonian age, mainly gold mineralization is formed. Also, in the Upper Jurassic – Lower Cretaceous ages, rarely-encountered Cu-polymetallic ore formations are documented. Finally, in the last stage, the re-dislocation of ore-formation is foreseen in the previously-formed mineralization areas. The faults in the strike and dip directions formed shearing, brecciation, sulfide mineralization aureoles, and hydrothermal alteration zones in the wall rocks along with the local depression blocks. The geological-structural analysis of the area shows that multiple and various morphogenetic volcano-tectonically fault systems have developed in the area. These fault systems have played a trap role for ore-formation in the intersected parts of faults mentioned above. Thus, in the referred parts, mostly predominance of felsic volcanism and metasomatic alteration (silicification, argillitic, etc.) of wall rocks, as well as the products of this volcanism, account for the inclusion of hydrothermal ore-forming fluids along these faults. It is possible to determine temporally and lithological-structural connection between the ore-formation along with local depression blocks and faults as borders for products of felsic volcanism of Upper Cretaceous-Lesser Jurassic ages, in the results of the replacement of hydrothermal alteration zones with relatively low-temperature metasomatic alterations while moving from the felsic parts to the margins, and due to being non-ore bearing intermediate and intermediate-felsic magmatic facies.

Keywords: Aghyokhush, fault, gold deposit, Mereh

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Authors: Ariadna Gassiot, Raquel Camprubi, Lluis Coromina

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Creative tourism involves the participation of tourists in the co-creation of their own experiences in a tourism destination. Consequently, creative tourists move from a passive behavior to an active behavior, and tourism destinations address this type of tourism by changing the scenario and making tourists learn and participate while they travel instead of merely offering tourism products and services to them. In creative tourism experiences, tourists are in close contact with locals and their culture. In destinations where culture (i.e. food, heritage, etc.) is the basis of their offer, such as Girona, Spain, tourism stakeholders must especially consider, analyze, and further foster the co-creation of authentic tourism experiences. They should focus on discovering more about these experiences, their main attributes, visitors’ opinions, etc. Creative tourists do not only participate while they travel around the world, but they also have and active post-travel behavior. They feel free to write about tourism experiences in different channels. User-generated content becomes crucial for any tourism destination when analyzing the market, making decisions, planning strategies, and when addressing issues, such as their reputation and performance. Sentiment analysis is a methodology used to automatically analyze semantic relationships and meanings in texts, so it is a way to extract tourists’ emotions and feelings. Tourists normally express their views and opinions regarding tourism products and services. They may express positive, neutral or negative feelings towards these products or services. For example, they may express anger, love, hate, sadness or joy towards tourism services and products. They may also express feelings through verbs, nouns, adverbs, adjectives, among others. Sentiment analysis may help tourism professionals in a range of areas, from marketing to customer service. For example, sentiment analysis allows tourism stakeholders to forecast tourism expenditure and tourist arrivals, or to analyze tourists’ profile. While there is an increasing presence of creativity in tourists’ experiences, there is also an increasing need to explore tourists’ expressions about these experiences. There is a need to know how they feel about participating in specific tourism activities. Thus, the main objective of this study is to analyze the meanings, emotions and feelings that tourists express about their creative experiences in Girona, Spain. To do so, sentiment analysis methodology is used. Results show the diversity of tourists who actively participate in tourism in Girona. Their opinions refer both to tangible aspects (e.g. food, museums, etc.) and to intangible aspects (e.g. friendliness, nightlife, etc.) of tourism experiences. Tourists express love, likeliness and other sentiments towards tourism products and services in Girona. This study can help tourism stakeholders in understanding tourists’ experiences and feelings. Consequently, they can offer more customized products and services and they can efficiently make them participate in the co-creation of their own tourism experiences.

Keywords: creative tourism, sentiment analysis, text mining, user-generated content

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Authors: Ilona Bontenbal

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In this research, the potential for societal change is researched through the idea of migrants as change agents. The viewpoint is on the potential that migrants have for affecting societal change in their country of origin through transmitting transnational peer-to-peer information. The focus is on the information that Russian migrants living in Finland transmit about their experiences and attitudes regarding the Nordic welfare state, its democratic foundation and the social rights embedded in it, to their family and friends in their country of origin. The welfare provision and level of democracy are very different in the two neighbouring countries of Finland and Russia. Finland is a Nordic welfare state with strong democratic institutions and a comprehensive actualizing of civil and social rights. In Russia, the state of democracy has on the other hand been declining, and the social and civil rights of its citizens are constantly undermined. Due to improvements in communications and travel technology, migrants can easily and relatively cheaply stay in contact with their family and friends in their country of origin. This is why it is possible for migrants to act as change agents. By telling about their experiences and attitudes about living in a democratic welfare state, migrants can affect what people in the country or origin know and think about welfare, democracy, and social rights. This phenomenon is approached through the concept of social remittances. Social remittances broadly stand for the ideas, know-how, world views, attitudes, norms of behavior, and social capital that flows through transnational networks from receiving- to sending- country communities and the other way around. The viewpoint is that historically and culturally formed democratic welfare models cannot be copied entirely nor that each country should achieve identical development paths, but rather that migrants themselves choose which aspects they see as important to remit to their acquaintances in their country of origin. This way the potential for social change and the agency of the migrants is accentuated. The empirical research material of this study is based on 30 qualitative interviews with Russian migrants living in Finland. Russians are the largest migrant group in Finland and Finland is a popular migration destination especially for individuals living in North-West Russia including the St. Petersburg region. The interviews are carried out in 2018-2019. The preliminary results indicate that Russian migrants discuss social rights and welfare a lot with their family members and acquaintances living in Russia. In general, the migrants feel that they have had an effect on the way that their friends and family think about Finland, the West, social rights and welfare provision. Democracy, on the other hand, is seen as a more difficult and less discussed topic. The transformative potential that the transmitted information and attitudes could have outside of the immediate circle of acquaintances on larger societal change is seen as ambiguous although not negligible.

Keywords: migrants as change agents, Russian migrants, social remittances, welfare and democracy

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Authors: Elena Petersen, Inna Kornienko, Svetlana Guryeva, Sergey Simakov

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In vitro organoid cultivation requires the simultaneous provision of necessary vascularization and nutrients perfusion of cells during organoid development. However, many aspects of this problem are still unsolved. The functionality of vascular network intergrowth is limited during early stages of organoid development since a function of the vascular network initiated on final stages of in vitro organoid cultivation. Therefore, a microchannel network should be created in early stages of organoid cultivation in hydrogel matrix aimed to conduct and maintain minimally required the level of nutrients perfusion for all cells in the expanding organoid. The network configuration should be designed properly in order to exclude hypoxic and necrotic zones in expanding organoid at all stages of its cultivation. In vitro vascularization is currently the main issue within the field of tissue engineering. As perfusion and oxygen transport have direct effects on cell viability and differentiation, researchers are currently limited only to tissues of few millimeters in thickness. These limitations are imposed by mass transfer and are defined by the balance between the metabolic demand of the cellular components in the system and the size of the scaffold. Current approaches include growth factor delivery, channeled scaffolds, perfusion bioreactors, microfluidics, cell co-cultures, cell functionalization, modular assembly, and in vivo systems. These approaches may improve cell viability or generate capillary-like structures within a tissue construct. Thus, there is a fundamental disconnect between defining the metabolic needs of tissue through quantitative measurements of oxygen and nutrient diffusion and the potential ease of integration into host vasculature for future in vivo implantation. A model is proposed for growth prognosis of the organoid perfusion based on joint simulations of general nutrient diffusion, nutrient diffusion to the hydrogel matrix through the contact surfaces and microchannels walls, nutrient consumption by the cells of expanding organoid, including biomatrix contraction during tissue development, which is associated with changed consumption rate of growing organoid cells. The model allows computing effective microchannel network design giving minimally required the level of nutrients concentration in all parts of growing organoid. It can be used for preliminary planning of microchannel network design and simulations of nutrients supply rate depending on the stage of organoid development.

Keywords: 3D model, consumption model, diffusion, spheroid, tissue organoid

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Authors: Fatima Zahra Mahjoubi, Abderrahim Khalidi, Mohamed Abdennouri, Omar Cherkaoui, Noureddine Barka

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Industrial effluents are one of the major causes of environmental pollution, especially effluents discharged from various dyestuff manufactures, plastic, and paper making industries. These effluents can give rise to certain hazards and environmental problems for their highly colored suspended organic solid. Dye effluents are not only aesthetic pollutants, but coloration of water by the dyes may affect photochemical activities in aquatic systems by reducing light penetration. It has been also reported that several commonly used dyes are carcinogenic and mutagenic for aquatic organisms. Therefore, removing dyes from effluents is of significant importance. Many adsorbent materials have been prepared in the removal of dyes from wastewater, including anionic clay or layered double hydroxyde. The zinc/aluminium (Zn-AlNO₃), magnesium/aluminium (Mg-AlNO₃) and nickel/aluminium (Ni-AlNO₃) layered double hydroxides (LDHs) were successfully synthesized via coprecipitation method. Samples were characterized by XRD, FTIR, TGA/DTA, TEM and pHPZC analysis. XRD patterns showed a basal spacing increase in the order of Zn-AlNO₃ (8.85Å)> Mg-AlNO₃ (7.95Å)> Ni-AlNO₃ (7.82Å). FTIR spectrum confirmed the presence of nitrate anions in the LDHs interlayer. The TEM images indicated that the Zn-AlNO3 presents circular to shaped particles with an average particle size of approximately 30 to 40 nm. Small plates assigned to sheets with hexagonal form were observed in the case of Mg-AlNO₃. Ni-AlNO₃ display nanostructured sphere in diameter between 5 and 10 nm. The LDHs were used as adsorbents for the removal of methyl orange (MO), as a model dye and for the treatment of an effluent generated by a textile factory. Adsorption experiments for MO were carried out as function of solution pH, contact time and initial dye concentration. Maximum adsorption was occurred at acidic solution pH. Kinetic data were tested using pseudo-first-order and pseudo-second-order kinetic models. The best fit was obtained with the pseudo-second-order kinetic model. Equilibrium data were correlated to Langmuir and Freundlich isotherm models. The best conditions for color and COD removal from textile effluent sample were obtained at lower values of pH. Total color removal was obtained with Mg-AlNO₃ and Ni-AlNO₃ LDHs. Reduction of COD to limits authorized by Moroccan standards was obtained with 0.5g/l LDHs dose.

Keywords: chemical oxygen demand, color removal, layered double hydroxides, textile wastewater treatment

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Authors: Jonathan Turner, Julie Doyle, Laura O’Philbin, Dympna O’Sullivan

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People living with dementia should be at the centre of decision-making regarding goals for daily living. These goals include basic activities (dressing, hygiene, and mobility), advanced activities (finances, transportation, and shopping), and meaningful activities that promote well-being (pastimes and intellectual pursuits). However, there is limited involvement of people living with dementia in the design of technology to support their goals. A project is described that is co-designing intelligent computer-based support for, and with, people affected by dementia and their carers. The technology will support self-management, empower participation in shared decision-making with carers and help people living with dementia remain healthy and independent in their homes for longer. It includes information from the patient’s care plan, which documents medications, contacts, and the patient's wishes on end-of-life care. Importantly for this work, the plan can outline activities that should be maintained or worked towards, such as exercise or social contact. The authors discuss how to integrate care goal information from such a care plan with data collected from passive sensors in the patient’s home in order to deliver individualized planning and interventions for persons with dementia. A number of scientific challenges are addressed: First, to co-design with dementia patients and their carers computerized support for shared decision-making about their care while allowing the patient to share the care plan. Second, to develop a new and open monitoring framework with which to configure sensor technologies to collect data about whether goals and actions specified for a person in their care plan are being achieved. This is developed top-down by associating care quality types and metrics elicited from the co-design activities with types of data that can be collected within the home, from passive and active sensors, and from the patient’s feedback collected through a simple co-designed interface. These activities and data will be mapped to appropriate sensors and technological infrastructure with which to collect the data. Third, the application of machine learning models to analyze data collected via the sensing devices in order to investigate whether and to what extent activities outlined via the care plan are being achieved. The models will capture longitudinal data to track disease progression over time; as the disease progresses and captured data show that activities outlined in the care plan are not being achieved, the care plan may recommend alternative activities. Disease progression may also require care changes, and a data-driven approach can capture changes in a condition more quickly and allow care plans to evolve and be updated.

Keywords: care goals, decision-making, dementia, self-care, sensors

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Authors: Hing Hao Chan, Thomas Richard, Masood Mostofi

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The mining industry relies on an estimate of rock strength at several stages of a mine life cycle: mining (excavating, blasting, tunnelling) and processing (crushing and grinding), both very energy-intensive activities. An effective comminution design that can yield significant dividends often requires a reliable estimate of the material rock strength. Common laboratory tests such as rod, ball mill, and uniaxial compressive strength share common shortcomings such as time, sample preparation, bias in plug selection cost, repeatability, and sample amount to ensure reliable estimates. In this paper, the authors present a methodology to derive an estimate of the rock strength from drilling data recorded while coring with a diamond core head. The work presented in this paper builds on a phenomenological model of the bit-rock interface proposed by Franca et al. (2015) and is inspired by the now well-established use of the scratch test with PDC (Polycrystalline Diamond Compact) cutter to derive the rock uniaxial compressive strength. The first part of the paper introduces the phenomenological model of the bit-rock interface for a diamond core head that relates the forces acting on the drill bit (torque, axial thrust) to the bit kinematic variables (rate of penetration and angular velocity) and introduces the intrinsic specific energy or the energy required to drill a unit volume of rock for an ideally sharp drilling tool (meaning ideally sharp diamonds and no contact between the bit matrix and rock debris) that is found well correlated to the rock uniaxial compressive strength for PDC and roller cone bits. The second part describes the laboratory drill rig, the experimental procedure that is tailored to minimize the effect of diamond polishing over the duration of the experiments, and the step-by-step methodology to derive the intrinsic specific energy from the recorded data. The third section presents the results and shows that the intrinsic specific energy correlates well to the uniaxial compressive strength for the 11 tested rock materials (7 sedimentary and 4 igneous rocks). The last section discusses best drilling practices and a method to estimate the rock strength from field drilling data considering the compliance of the drill string and frictional losses along the borehole. The approach is illustrated with a case study from drilling data recorded while drilling an exploration well in Australia.

Keywords: bit-rock interaction, drilling experiment, impregnated diamond drilling, uniaxial compressive strength

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Authors: Avtandil Okrostsvaridze, Salome Gogoladze

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In the light of exhaustion of hydrocarbon reserves of new energy resources, its search is of vital importance problem for the modern civilization. At the time of energy resource crisis, the radioactive element thorium (232Th) is considered as the main energy resource for the future of our civilization. Modern industry uses thorium in high-temperature and high-tech tools, but the most important property of thorium is that like uranium it can be used as fuel in nuclear reactors. However, thorium has a number of advantages compared to this element: Its concentration in the earth crust is 4-5 times higher than uranium; extraction and enrichment of thorium is much cheaper than of uranium; it is less radioactive; its waste products complete destruction is possible; thorium yields much more energy than uranium. Nowadays, developed countries, among them India and China, have started intensive work for creation of thorium nuclear reactors and intensive search for thorium reserves. It is not excluded that in the next 10 years these reactors will completely replace uranium reactors. Thorium ore mineralization is genetically related to alkaline-acidic magmatism. Thorium accumulations occur as in endogen marked as in exogenous conditions. Unfortunately, little is known about the reserves of this element in Georgia, as planned prospecting-exploration works of thorium have never been carried out here. Although, 3 ore occurrences of this element are detected: 1) In the Greater Caucasus Kakheti segment, in the hydrothermally altered rocks of the Lower Jurassic clay-shales, where thorium concentrations varied between 51 - 3882g/t; 2) In the eastern periphery of the Dzirula massif, in the hydrothermally alteration rocks of the cambrian quartz-diorite gneisses, where thorium concentrations varied between 117-266 g/t; 3) In active contact zone of the Eocene volcanites and syenitic intrusive in Vakijvari ore field of the Guria region, where thorium concentrations varied between 185 – 428 g/t. In addition, geological settings of the areas, where thorium occurrences were fixed, give a theoretical basis on possible accumulation of practical importance thorium ores. Besides, the Black Sea Guria region magnetite sand which is transported from Vakijvari ore field, should contain significant reserves of thorium. As the research shows, monazite (thorium containing mineral) is involved in magnetite in the form of the thinnest inclusions. The world class thorium deposit concentrations of this element vary within the limits of 50-200 g/t. Accordingly, on the basis of these data, thorium resources found in Georgia should be considered as perspective ore deposits. Generally, we consider that complex investigation of thorium should be included into the sphere of strategic interests of the state, because future energy of Georgia, will probably be thorium.

Keywords: future energy, Georgia, ore field, thorium

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Authors: Katharina Kargel, Frederic Vobbe

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Sexual online grooming is generally defined as digital interactions for the purpose of sexual exploitation of children or minors, i.e. as a process for preparing and framing sexual child abuse. Due to its conceptual history, sexual online grooming is often associated with perpetrators who are previously unknown to those affected. While the strategies of perpetrators and the perception of those affected are increasingly being investigated, the instrumentalisation of digital media has not yet been researched much. Therefore, the present paper aims at contributing to this research gap by examining in what kind of ways perpetrators instrumentalise digital media. Our analyses draw on 46 case documentations and 18 interviews with those affected. The cases and the partly narrative interviews were collected by ten cooperating specialist centers working on sexualized violence in childhood and youth. For this purpose, we designed a documentation grid allowing for a detailed case reconstruction i.e. including information on the violence, digital media use and those affected. By using Reflexive Grounded Theory, our analyses emphasize a) the subjective benchmark of professional practitioners as well as those affected and b) the interpretative implications resulting from our researchers’ subjective and emotional interaction with the data material. It should first be noted that sexualized online grooming can result in both online and offline sexualized violence as well as hybrid forms. Furthermore, the perpetrators either come from the immediate social environment of those affected or are unknown to them. The perpetrator-victim relationship plays a more important role with regard to the question of the instrumentalisation of digital media than the question of the space (on vs. off) in which the primary violence is committed. Perpetrators unknown to those affected instrumentalise digital media primarily to establish a sexualized system of norms, which is usually embedded in a supposed love relationship. In some cases, after an initial exchange of sexualized images or video recordings, a latent play on the position of power takes place. In the course of the grooming process, perpetrators from the immediate social environment increasingly instrumentalise digital media to establish an explicit relationship of power and dependence, which is directly determined by coercion, threats and blackmail. The knowledge of possible vulnerabilities is strategically used in the course of maintaining contact. The above explanations lead to the conclusion that the motive for the crime plays an essential role in the question of the instrumentalisation of digital media. It is therefore not surprising that it is mostly the near-field perpetrators without commercial motives who initiate a spiral of violence and stress by digitally distributing sexualized (violent) images and video recordings within the reference system of those affected.

Keywords: sexualized violence, children and youth, grooming, offender strategies, digital media

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Authors: Maksudur Rahman Khan, Kar Min Chan, Huei Ruey Ong, Chin Kui Cheng, Wasikur Rahman

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Microbial fuel cells (MFCs) represent a promising technology for simultaneous bioelectricity generation and wastewater treatment. Catalysts are significant portions of the cost of microbial fuel cell cathodes. Many materials have been tested as aqueous cathodes, but air-cathodes are needed to avoid energy demands for water aeration. The sluggish oxygen reduction reaction (ORR) rate at air cathode necessitates efficient electrocatalyst such as carbon supported platinum catalyst (Pt/C) which is very costly. Manganese oxide (MnO2) was a representative metal oxide which has been studied as a promising alternative electrocatalyst for ORR and has been tested in air-cathode MFCs. However, the single MnO2 has poor electric conductivity and low stability. In the present work, the MnO2 catalyst has been modified by doping Pt nanoparticle. The goal of the work was to improve the performance of the MFC with minimum Pt loading. MnO2 and Pt nanoparticles were prepared by hydrothermal and sol-gel methods, respectively. Wet impregnation method was used to synthesize Pt/MnO2 catalyst. The catalysts were further used as cathode catalysts in air-cathode cubic MFCs, in which anaerobic sludge was inoculated as biocatalysts and palm oil mill effluent (POME) was used as the substrate in the anode chamber. The as-prepared Pt/MnO2 was characterized comprehensively through field emission scanning electron microscope (FESEM), X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) where its surface morphology, crystallinity, oxidation state and electrochemical activity were examined, respectively. XPS revealed Mn (IV) oxidation state and Pt (0) nanoparticle metal, indicating the presence of MnO2 and Pt. Morphology of Pt/MnO2 observed from FESEM shows that the doping of Pt did not cause change in needle-like shape of MnO2 which provides large contacting surface area. The electrochemical active area of the Pt/MnO2 catalysts has been increased from 276 to 617 m2/g with the increase in Pt loading from 0.2 to 0.8 wt%. The CV results in O2 saturated neutral Na2SO4 solution showed that MnO2 and Pt/MnO2 catalysts could catalyze ORR with different catalytic activities. MFC with Pt/MnO2 (0.4 wt% Pt) as air cathode catalyst generates a maximum power density of 165 mW/m3, which is higher than that of MFC with MnO2 catalyst (95 mW/m3). The open circuit voltage (OCV) of the MFC operated with MnO2 cathode gradually decreased during 14 days of operation, whereas the MFC with Pt/MnO2 cathode remained almost constant throughout the operation suggesting the higher stability of the Pt/MnO2 catalyst. Therefore, Pt/MnO2 with 0.4 wt% Pt successfully demonstrated as an efficient and low cost electrocatalyst for ORR in air cathode MFC with higher electrochemical activity, stability and hence enhanced performance.

Keywords: microbial fuel cell, oxygen reduction reaction, Pt/MnO2, palm oil mill effluent, polarization curve

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Authors: David Sinfield, Thomas Cochrane, Marcos Steagall

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While there is much hype around the potential and development of mobile virtual reality (VR), the two key critical success factors are the ease of user experience and the development of a simple user-generated content ecosystem. Educational technology history is littered with the debris of over-hyped revolutionary new technologies that failed to gain mainstream adoption or were quickly superseded. Examples include 3D television, interactive CDROMs, Second Life, and Google Glasses. However, we argue that this is the result of curriculum design that substitutes new technologies into pre-existing pedagogical strategies that are focused upon teacher-delivered content rather than exploring new pedagogical strategies that enable student-determined learning or heutagogy. Visual Communication design based learning such as Graphic Design, Illustration, Photography and Design process is heavily based on the traditional forms of the classroom environment whereby student interaction takes place both at peer level and indeed teacher based feedback. In doing so, this makes for a healthy creative learning environment, but does raise other issue in terms of student to teacher learning ratios and reduced contact time. Such issues arise when students are away from the classroom and cannot interact with their peers and teachers and thus we see a decline in creative work from the student. Using AR and VR as a means of stimulating the students and to think beyond the limitation of the studio based classroom this paper will discuss the outcomes of a student project considering the virtual classroom and the techniques involved. The Atelier learning environment is especially suited to the Visual Communication model as it deals with the creative processing of ideas that needs to be shared in a collaborative manner. This has proven to have been a successful model over the years, in the traditional form of design education, but has more recently seen a shift in thinking as we move into a more digital model of learning and indeed away from the classical classroom structure. This study focuses on the outcomes of a student design project that employed Augmented Reality and Virtual Reality technologies in order to expand the dimensions of the classroom beyond its physical limits. Augmented Reality when integrated into the learning experience can improve the learning motivation and engagement of students. This paper will outline some of the processes used and the findings from the semester-long project that took place.

Keywords: augmented reality, blogging, design in community, enhanced learning and teaching, graphic design, new technologies, virtual reality, visual communications

Procedia PDF Downloads 238

Authors: Noriyuki Suyama

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This paper discusses purchasing behavior in retail stores, with a particular focus on the impact of weather changes on customers' purchasing behavior. Weather conditions are one of the factors that greatly affect the management and operation of retail stores. However, there is very little research on the relationship between weather conditions and marketing from an academic perspective, although there is some importance from a practical standpoint and knowledge based on experience. For example, customers are more hesitant to go out when it rains than when it is sunny, and they may postpone purchases or buy only the minimum necessary items even if they do go out. It is not difficult to imagine that weather has a significant impact on consumer behavior. To the best of the authors' knowledge, there have been only a few studies that have delved into the purchasing behavior of individual customers. According to Hirata (2018), the economic impact of weather in the United States is estimated to be 3.4% of GDP, or "$485 billion ± $240 billion per year. However, weather data is not yet fully utilized. Representative industries include transportation-related industries (e.g., airlines, shipping, roads, railroads), leisure-related industries (e.g., leisure facilities, event organizers), energy and infrastructure-related industries (e.g., construction, factories, electricity and gas), agriculture-related industries (e.g., agricultural organizations, producers), and retail-related industries (e.g., retail, food service, convenience stores, etc.). This paper focuses on the retail industry and advances research on weather. The first reason is that, as far as the author has investigated the retail industry, only grocery retailers use temperature, rainfall, wind, weather, and humidity as parameters for their products, and there are very few examples of academic use in other retail industries. Second, according to NBL's "Toward Data Utilization Starting from Consumer Contact Points in the Retail Industry," labor productivity in the retail industry is very low compared to other industries. According to Hirata (2018) mentioned above, improving labor productivity in the retail industry is recognized as a major challenge. On the other hand, according to the "Survey and Research on Measurement Methods for Information Distribution and Accumulation (2013)" by the Ministry of Internal Affairs and Communications, the amount of data accumulated by each industry is extremely large in the retail industry, so new applications are expected by analyzing these data together with weather data. Third, there is currently a wealth of weather-related information available. There are, for example, companies such as WeatherNews, Inc. that make weather information their business and not only disseminate weather information but also disseminate information that supports businesses in various industries. Despite the wide range of influences that weather has on business, the impact of weather has not been a subject of research in the retail industry, where business models need to be imagined, especially from a micro perspective. In this paper, the author discuss the important aspects of the impact of weather on marketing strategies in the non-food retail industry.

Keywords: consumer behavior, weather marketing, marketing science, big data, retail marketing

Procedia PDF Downloads 81

Authors: Panagiotis Lemonakis, Theodoros Αlimonakis, George Kaliabetsos, Nikos Eliou

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It is very well known that certain vertical and longitudinal slopes have to be assured in order to achieve adequate rainwater runoff from the pavement. The selection of longitudinal slopes, between the turning points of the vertical curves that meet the afore-mentioned requirement does not ensure adequate drainage because the same condition must also be applied at the transition curves. In this way none of the pavement edges’ slopes (as well as any other spot that lie on the pavement) will be opposite to the longitudinal slope of the rotation axis. Horizontal and vertical alignment must be properly combined in order to form a road which resultant slope does not take small values and hence, checks must be performed in every cross section and every chainage of the road. The present research investigates the rain water runoff from the road surface in order to identify the conditions under which, areas of inadequate drainage are being created, to analyze the rainwater behavior in such areas, to provide design examples of good and bad drainage zones and to track down certain motorcycle types which might encounter hazardous situations due to the presence of water film between the pavement and both of their tires resulting loss of traction. Moreover, it investigates the combination of longitudinal and cross slope values in critical pavement areas. It should be pointed out that the drainage gradient is analytically calculated for the whole road width and not just for an oblique slope per chainage (combination of longitudinal grade and cross slope). Lastly, various combinations of horizontal and vertical design are presented, indicating the crucial zones of bad pavement drainage. The key conclusion of the study is that any type of motorcycle will travel for some time inside the area of improper runoff for a certain time frame which depends on the speed and the trajectory that the rider chooses along the transition curve. Taking into account that on this section the rider will have to lean his motorcycle and hence reduce the contact area of his tire with the pavement it is apparent that any variations on the friction value due to the presence of a water film may lead to serious problems regarding his safety. The water runoff from the road pavement is improved when between reverse longitudinal slopes, crest instead of sag curve is chosen and particularly when its edges coincide with the edges of the horizontal curve. Lastly, the results of the investigation have shown that the variation of the longitudinal slope involves the vertical shift of the center of the poor water runoff area. The magnitude of this area increases as the length of the transition curve increases.

Keywords: drainage, motorcycle safety, superelevation, transition curves, vertical grade

Procedia PDF Downloads 100

Authors: Pin-Ling Yin, Dung-Ying Lin

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Satellites play an important role in our daily lives, from monitoring the Earth's environment and providing real-time disaster imagery to predicting extreme weather events. As technology advances and demands increase, the tasks undertaken by satellites have become increasingly complex, with more stringent resource management requirements. A common challenge in satellite mission scheduling is the limited availability of resources, including onboard memory, ground station accessibility, and satellite power. In this context, efficiently scheduling and managing the increasingly complex satellite missions under constrained resources has become a critical issue that needs to be addressed. The core of Satellite Onboard Activity Planning (SOAP) lies in optimizing the scheduling of the received tasks, arranging them on a timeline to form an executable onboard mission plan. This study aims to develop an optimization model that considers the various constraints involved in satellite mission scheduling, such as the non-overlapping execution periods for certain types of tasks, the requirement that tasks must fall within the contact range of specified types of ground stations during their execution, onboard memory capacity limits, and the collaborative constraints between different types of tasks. Specifically, this research constructs a mixed-integer programming mathematical model and solves it with a commercial optimization package. Simultaneously, as the problem size increases, the problem becomes more difficult to solve. Therefore, in this study, a heuristic algorithm has been developed to address the challenges of using commercial optimization package as the scale increases. The goal is to effectively plan satellite missions, maximizing the total number of executable tasks while considering task priorities and ensuring that tasks can be completed as early as possible without violating feasibility constraints. To verify the feasibility and effectiveness of the algorithm, test instances of various sizes were generated, and the results were validated through feedback from on-site users and compared against solutions obtained from a commercial optimization package. Numerical results show that the algorithm performs well under various scenarios, consistently meeting user requirements. The satellite mission scheduling algorithm proposed in this study can be flexibly extended to different types of satellite mission demands, achieving optimal resource allocation and enhancing the efficiency and effectiveness of satellite mission execution.

Keywords: mixed-integer programming, meta-heuristics, optimization, resource management, satellite mission scheduling

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Authors: Rabindranath Jana, Biswajit Maity, Keka Rana

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The most promising clean energy source is the fuel cell, since it does not generate toxic gases and other hazardous compounds. Again the direct methanol fuel cell (DMFC) is more user-friendly as it is easy to be miniaturized and suited as energy source for automobiles as well as domestic applications and portable devices. And unlike the hydrogen used for some fuel cells, methanol is a liquid that is easy to store and transport in conventional tanks. The most important part of a fuel cell is its membrane. Till now, an overall efficiency for a methanol fuel cell is reported to be about 20 ~ 25%. The lower efficiency of the cell may be due to the critical factors, e.g. slow reaction kinetics at the anode and methanol crossover. The oxidation of methanol is composed of a series of successive reactions creating formaldehyde and formic acid as intermediates that contribute to slow reaction rates and decreased cell voltage. Currently, the investigation of new anode catalysts to improve oxidation reaction rates is an active area of research as it applies to the methanol fuel cell. Surprisingly, there are very limited reports on nanostructured membranes, which are rather simple to manufacture with different tuneable compositions and are expected to allow only the proton permeation but not the methanol due to their molecular sizing effects and affinity to the membrane surface. We have developed a nanostructured fuel cell membrane from polydimethyl siloxane rubber (PDMS), ethylene methyl co-acrylate (EMA) and multi-walled carbon nanotubes (MWNTs). The effect of incorporating different proportions of f-MWNTs in polymer membrane has been studied. The introduction of f-MWNTs in polymer matrix modified the polymer structure, and therefore the properties of the device. The proton conductivity, measured by an AC impedance technique using open-frame and two-electrode cell and methanol permeability of the membranes was found to be dependent on the f-MWNTs loading. The proton conductivity of the membranes increases with increase in concentration of f-MWNTs concentration due to increased content of conductive materials. Measured methanol permeabilities at 60oC were found to be dependant on loading of f-MWNTs. The methanol permeability decreased from 1.5 x 10-6 cm²/s for pure film to 0.8 x 10-7 cm²/s for a membrane containing 0.5wt % f-MWNTs. This is due to increasing proportion of f-MWNTs, the matrix becomes more compact. From DSC melting curves it is clear that the polymer matrix with f-MWNTs is thermally stable. FT-IR studies show good interaction between EMA and f-MWNTs. XRD analysis shows good crystalline behavior of the prepared membranes. Significant cost savings can be achieved when using the blended films which contain less expensive polymers.

Keywords: fuel cell membrane, polydimethyl siloxane rubber, carbon nanotubes, proton conductivity, methanol permeability

Procedia PDF Downloads 413

Authors: Abdolrasoul Daneshjoo

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Soccer is a game which draws more attention in different countries especially in Brazil. Kicking among different skills in soccer and soccer players is an excellent role for the success and preference of a team. The way of point gaining in this game is passing the ball over the goal lines which are gained by shoot skill in attack time and or during the penalty kicks.Regarding the above assumption, identifying the effective factors in instep kicking in different distances shoot with maximum force and high accuracy or pass and penalty kick, may assist the coaches and players in raising qualitative level of performing the skill.The aim of the present study was to study of a few kinematical parameters in instep kicking from 5 and 7 meter distance among the male and female elite soccer players.24 right dominant lower limb subjects (12 males and 12 females) among Tehran elite soccer players with average and the standard deviation (22.5 ± 1.5) & (22.08± 1.31) years, height of (179.5 ± 5.81) & (164.3 ± 4.09) cm, weight of (69.66 ± 4.09) & (53.16 ± 3.51) kg, %BMI (21.06 ± .731) & (19.67 ± .709), having playing history of (4 ± .73) & (3.08 ± .66) years respectively participated in this study. They had at least two years of continuous playing experience in Tehran soccer league.For sampling player's kick; Kinemetrix Motion analysis with three cameras with 1000 Hz was used. Five reflective markers were placed laterally on the kicking leg over anatomical points (the iliac crest, major trochanter, lateral epicondyle of femur, lateral malleolus, and lateral aspect of distal head of the fifth metatarsus). Instep kick was filmed, with one step approach and 30 to 45 degrees angle from stationary ball. Three kicks were filmed, one kick selected for further analyses. Using Kinemetrix 3D motion analysis software, the position of the markers was analyzed. Descriptive statistics were used to describe the mean and standard deviation, while the analysis of variance, and independent t-test (P < 0.05) were used to compare the kinematic parameters between two genders.Among the evaluated parameters, the knee acceleration, the thigh angular velocity, the angle of knee proportionately showed significant relationship with consequence of kick. While company performance on 5m in 2 genders, significant differences were observed in internal – external displacement of toe, ankle, hip and the velocity of toe, ankle and the acceleration of toe and the angular velocity of pelvic, thigh and before time contact . Significant differences showed the internal – external displacement of toe, the ankle, the knee and the hip, the iliac crest and the velocity of toe, the ankle and acceleration of ankle and angular velocity of the pelvic and the knee.

Keywords: biomechanics, kinematics, instep kicking, soccer

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Authors: Lorenza Sganzetta, Nunzia Borrelli

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The research intends to reflect on the current mapping of the Food Strategies, on the reasons why in the planning objectives panorama, such sustainability priorities are located in those geographic areas and on the evolutions of these priorities of the Mediterranean planning dispositions. The whirling population growth that is affecting global cities is causing an enormous challenge to conventional resource-intensive food production and supply and the urgent need to face food safety, food security and sustainability concerns. Urban or Territorial Food Strategies can provide an interesting path for the development of this new agenda within the imperative principle of sustainability. In the specific, it is relevant to explore what ‘sustainability’ means within these policies. Most of these plans include actions related to four main components and interpretations of sustainability that are food security and safety, food equity, environmental sustainability itself and cultural identity and, at the designing phase, they differ slightly from each other according to the degree of approximation to one of these dimensions. Moving from these assumptions, the article would analyze some practices and policies representatives of different Food Strategies of the world and focus on the Mediterranean ones, on the problems and negative externalities from which they start, on the first interventions that are implementing and on their main objectives. We will mainly use qualitative data from primary and secondary collections. So far, an essential observation could have been made about the relationship between these sustainability dimensions and geography. In statistical terms, the US and Canadian policies tended to devote a large research space to health issues and access to food; those northern European showed a special attention to the environmental issues and the shortening of the chain; and finally the policies that, even in limited numbers, were being developed in the Mediterranean basin, were characterized by a strong territorial and cultural imprint and their major aim was to preserve local production and the contact between the productive land and the end consumer. Recently, though, Mediterranean food planning strategies are focusing more on health related and food accessibility issues and analyzing our diets not just as a matter of culture and territorial branding but as tools for reducing public health costs and accessibility to fresh food for everyone. The article would reflect then on how Food Safety, Food Security and Health are entering the new agenda of the Mediterranean Food Strategies. The research hypothesis suggests that the economic crisis that in the last years invested both producers and consumers had a significant impact on the nutrition habits and on the redefinition of food poverty, even in the fatherland of the healthy Mediterranean diet. This trend and other variables influenced the orientation and the objectives of the food strategies.

Keywords: food security, food strategy, health, sustainability

Procedia PDF Downloads 223

Authors: Augustus K. Lebechi, Kenneth I. Ozoemena

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Rechargeable zinc-air batteries (RZABs) have been described as one of the most viable next-generation ‘beyond-the-lithium-ion’ battery technologies with great potential for renewable energy storage. It is safe, with a high specific energy density (1086 Wh/kg), environmentally benign, and low-cost, especially in resource-limited African countries. For widespread commercialization, the sluggish oxygen reaction kinetics pose a major challenge that impedes the reversibility of the system. Hence, there is a need for low-cost and highly active bifunctional electrocatalysts. Manganese oxide catalysts on carbon conducting additives remain the best couple for the realization of such low-cost RZABs. In this work, hausmannite Mn₃O₄ nanoparticles were synthesized through the annealing method from commercial electrolytic manganese dioxide (EMD), multi-walled carbon nanotubes (MWCNTs) were synthesized via the chemical vapor deposition (CVD) method and carbon nanofibers (CNFs) were synthesized via the electrospinning process with subsequent carbonization. Both Mn₃O₄ catalysts and the carbon conducting additives (MWCNT and CNF) were thoroughly characterized using X-ray powder diffraction spectroscopy (XRD), scanning electron microscopy (SEM), thermogravimetry analysis (TGA) and X-ray photoelectron spectroscopy (XPS). Composite electrocatalysts (Mn₃O₄/CNT and Mn₃O₄/CNF) were investigated for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) in an alkaline medium. Using the established electrocatalytic modalities for evaluating the electrocatalytic performance of materials (including double layer, electrochemical active surface area, roughness factor, specific current density, and catalytic stability), CNFs proved to be the most efficient conducting additive material for the Mn₃O₄ catalyst. From the DFT calculations, the higher performance of the CNFs over the MWCNTs is related to the ability of the CNFs to allow for a more favorable distribution of the d-electrons of the manganese (Mn) and enhanced synergistic effect with Mn₃O₄ for weaker adsorption energies of the oxygen intermediates (O*, OH* and OOH*). In a proof-of-concept, Mn₃O₄/CNF was investigated as the air cathode for rechargeable zinc-air battery (RZAB) in a micro-3D-printed cell configuration. The RZAB showed good performance in terms of open circuit voltage (1.77 V), maximum power density (177.5 mW cm-2), areal-discharge energy and cycling stability comparable to Pt/C (20 wt%) + IrO2. The findings here provide fresh physicochemical perspectives on the future design and utility of CNFs for developing manganese-based RZABs.

Keywords: bifunctional electrocatalyst, oxygen evolution reaction, oxygen reduction reactions, rechargeable zinc-air batteries.

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Authors: Ainur Sharip, Jose E. Perez, Nouf Alsharif, Aldo I. M. Bandeas, Enzo D. Fabrizio, Timothy Ravasi, Jasmeen S. Merzaban, Jürgen Kosel

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Bone marrow-derived human mesenchymal stem cells (MSCs) are attractive candidates for tissue engineering and regenerative medicine, due to their ability to differentiate into osteoblasts, chondrocytes or adipocytes. Differentiation is influenced by biochemical and biophysical stimuli provided by the microenvironment of the cell. Thus, altering the mechanical characteristics of a cell culture scaffold can directly influence a cell’s microenvironment and lead to stem cell differentiation. Mesenchymal stem cells were cultured on densely packed, vertically aligned magnetic iron nanowires (NWs) and the effect of NWs on the cell cytoskeleton rearrangement and differentiation were studied. An electrochemical deposition method was employed to fabricate NWs into nanoporous alumina templates, followed by a partial release to reveal the NW array. This created a cell growth substrate with free-standing NWs. The Fe NWs possessed a length of 2-3 µm, with each NW having a diameter of 33 nm on average. Mechanical stimuli generated by the physical movement of these iron NWs, in response to a magnetic field, can stimulate osteogenic differentiation. Induction of osteogenesis was estimated using an osteogenic marker, osteopontin, and a reduction of stem cell markers, CD73 and CD105. MSCs were grown on the NWs, and fluorescent microscopy was employed to monitor the expression of markers. A magnetic field with an intensity of 250 mT and a frequency of 0.1 Hz was applied for 12 hours/day over a period of one week and two weeks. The magnetically activated substrate enhanced the osteogenic differentiation of the MSCs compared to the culture conditions without magnetic field. Quantification of the osteopontin signal revealed approximately a seven-fold increase in the expression of this protein after two weeks of culture. Immunostaining staining against CD73 and CD105 revealed the expression of antibodies at the earlier time point (two days) and a considerable reduction after one-week exposure to a magnetic field. Overall, these results demonstrate the application of a magnetic NW substrate in stimulating the osteogenic differentiation of MSCs. This method significantly decreases the time needed to induce osteogenic differentiation compared to commercial biochemical methods, such as osteogenic differentiation kits, that usually require more than two weeks. Contact-free stimulation of MSC differentiation using a magnetic field has potential uses in tissue engineering, regenerative medicine, and bone formation therapies.

Keywords: cell substrate, magnetic nanowire, mesenchymal stem cell, stem cell differentiation

Procedia PDF Downloads 196

Authors: Ali H. Daraji, Jack M. Hale, Ye Jianqiao

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With the extensive use of high specific strength structures to optimise the loading capacity and material cost in aerospace and most engineering applications, much effort has been expended to develop intelligent structures for active vibration reduction and structural health monitoring. These structures are highly flexible, inherently low internal damping and associated with large vibration and long decay time. The modification of such structures by adding lightweight piezoelectric sensors and actuators at efficient locations integrated with an optimal control scheme is considered an effective solution for structural vibration monitoring and controlling. The size and location of sensor and actuator are important research topics to investigate their effects on the level of vibration detection and reduction and the amount of energy provided by a controller. Several methodologies have been presented to determine the optimal location of a limited number of sensors and actuators for small-scale structures. However, these studies have tackled this problem directly, measuring the fitness function based on eigenvalues and eigenvectors achieved with numerous combinations of sensor/actuator pair locations and converging on an optimal set using heuristic optimisation techniques such as the genetic algorithms. This is computationally expensive for small- and large-scale structures subject to optimise a number of s/a pairs to suppress multiple vibration modes. This paper proposes an efficient method to determine optimal locations for a limited number of sensor/actuator pairs for active vibration reduction of a flexible structure based on finite element method and Hamilton’s principle. The current work takes the simplified approach of modelling a structure with sensors at all locations, subjecting it to an external force to excite the various modes of interest and noting the locations of sensors giving the largest average percentage sensors effectiveness measured by dividing all sensor output voltage over the maximum for each mode. The methodology was implemented for a cantilever plate under external force excitation to find the optimal distribution of six sensor/actuator pairs to suppress the first six modes of vibration. It is shown that the results of the optimal sensor locations give good agreement with published optimal locations, but with very much reduced computational effort and higher effectiveness. Furthermore, it is shown that collocated sensor/actuator pairs placed in these locations give very effective active vibration reduction using optimal linear quadratic control scheme.

Keywords: optimisation, plate, sensor effectiveness, vibration control

Procedia PDF Downloads 231

Authors: Mehran Nozari-Asbemarz, Italo Pisano, Simin Arshi, Edmond Magner, James J. Leahy

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Integrating electrolytic synthesis with renewable energy makes it feasible to address urgent environmental and energy challenges. Conventional water electrolyzers concurrently produce H₂ and O₂, demanding additional procedures in gas separation to prevent contamination of H₂ with O₂. Moreover, the oxygen evolution reaction (OER), which is sluggish and has a low overall energy conversion efficiency, does not deliver a significant value product on the electrode surface. Compared to conventional water electrolysis, integrating electrolytic hydrogen generation from water with thermodynamically more advantageous aqueous organic oxidation processes can increase energy conversion efficiency and create value-added compounds instead of oxygen at the anode. One strategy is to use renewable and sustainable carbon sources from biomass, which has a large annual production capacity and presents a significant opportunity to supplement carbon sourced from fossil fuels. Numerous catalytic techniques have been researched in order to utilize biomass economically. Because of its safe operating conditions, excellent energy efficiency, and reasonable control over production rate and selectivity using electrochemical parameters, electrocatalytic upgrading stands out as an appealing choice among the numerous biomass refinery technologies. Therefore, we propose a broad framework for coupling H2 generation from water splitting with oxidative biomass upgrading processes. Four representative biomass targets were considered for oxidative upgrading that used a hierarchically porous CoFe-MOF/LDH @ Graphite Paper bifunctional electrocatalyst, including glucose, ethanol, benzyl, furfural, and 5-hydroxymethylfurfural (HMF). The potential required to support 50 mA cm-2 is considerably lower than (~ 380 mV) the potential for OER. All four compounds can be oxidized to yield liquid byproducts with economic benefit. The electrocatalytic oxidation of glucose to the value-added products, gluconic acid, glucuronic acid, and glucaric acid, was examined in detail. The cell potential for combined H₂ production and glucose oxidation was substantially lower than for water splitting (1.44 V(RHE) vs. 1.82 V(RHE) for 50 mA cm-2). In contrast, the oxidation byproduct at the anode was significantly more valuable than O₂, taking advantage of the more favorable glucose oxidation in comparison to the OER. Overall, such a combination of HER and oxidative biomass valorization using electrocatalysts prevents the production of potentially explosive H₂/O₂mixtures and produces high-value products at both electrodes with lower voltage input, thereby increasing the efficiency and activity of electrocatalytic conversion.

Keywords: biomass, electrocatalytic, glucose oxidation, hydrogen evolution

Procedia PDF Downloads 96

Authors: Edward R. Moad

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Al-Ghazali’s Tahāfat al Falāsifa is widely construed as an attack on philosophy in favor of theological fideism. Consequently, he has been blamed for ‘death of philosophy’ in the Muslim world. ‘Falsifa’ however is not philosophy itself, but rather a range of philosophical doctrines mainly influenced by or inherited form Greek thought. In these terms, this work represents a defense of philosophy against what we could call ‘falsifical’ fideism. In the introduction, Ghazali describes his target audience as, not the falasifa, but a group of pretenders engaged in taqlid to a misconceived understanding of falasifa, including the belief that they were capable of demonstrative certainty in the field of metaphysics. He promises to use falsifa standards of logic (with which he independently agrees), to show that that the falasifa failed to demonstratively prove many of their positions. Whether or not he succeeds in that, the exercise of subjecting alleged proofs to critical scrutiny is quintessentially philosophical, while uncritical adherence to a doctrine, in the name of its being ‘philosophical’, is decidedly unphilosophical. If we are to blame the intellectual decline of the Muslim world on someone’s ‘bad’ way of thinking, rather than more material historical circumstances (which is already a mistake), then blame more appropriately rests with modernist Muslim thinkers who, under the influence of orientalism (and like Ghazali’s philosophical pretenders) mistook taqlid to the falasifa as philosophy itself. The discussion of the Tahāfut takes place in the context of an epistemic (and related social) hierarchy envisioned by the falasifa, corresponding to the faculties of the sense, the ‘estimative imagination’ (wahm), and the pure intellect, along with the respective forms of discourse – rhetoric, dialectic, and demonstration – appropriate to each category of that order. Al-Farabi in his Book of Letters describes a relation between dialectic and demonstration on the one hand, and theology and philosophy on the other. The latter two are distinguished by method rather than subject matter. Theology is that which proceeds dialectically, while philosophy is (or aims to be?) demonstrative. Yet, Al-Farabi tells us, dialectic precedes philosophy like ‘nourishment for the tree precedes its fruit.’ That is, dialectic is part of the process, by which we interrogate common and imaginative notions in the pursuit of clearly understood first principles that we can then deploy in the demonstrative argument. Philosophy is, therefore, something we aspire to through, and from a discursive condition of, dialectic. This stands in apparent contrast to the understanding of Ibn Sina, for whom one arrives at the knowledge of first principles through contact with the Active Intellect. It also stands in contrast to that of Ibn Rushd, who seems to think our knowledge of first principles can only come through reading Aristotle. In conclusion, based on Al-Farabi’s framework, Ghazali’s Tahafut is a truly an exercise in philosophy, and an effort to keep the door open for true philosophy in the Muslim mind, against the threat of a kind of developing theology going by the name of falsifa.

Keywords: philosophy, incoherence, theology, Tahafut

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Authors: E. G. Karvelas, C. Liosis, A. Theodorakakos, T. E. Karakasidis

Abstract:

Magnetic navigation of the drug inside the human vessels is a very important concept since the drug is delivered to the desired area. Consequently, the quantity of the drug required to reach therapeutic levels is being reduced while the drug concentration at targeted sites is increased. Magnetic navigation of drug agents can be achieved with the use of magnetic nanoparticles where anti-tumor agents are loaded on the surface of the nanoparticles. The magnetic field that is required to navigate the particles inside the human arteries is produced by a magnetic resonance imaging (MRI) device. The main factors which influence the efficiency of the usage of magnetic nanoparticles for biomedical applications in magnetic driving are the size and the magnetization of the biocompatible nanoparticles. In this study, a computational platform for the simulation of the optimal gradient magnetic fields for the navigation of magnetic nanoparticles inside a carotid artery is presented. For the propulsion model of the particles, seven major forces are considered, i.e., the magnetic force from MRIs main magnet static field as well as the magnetic field gradient force from the special propulsion gradient coils. The static field is responsible for the aggregation of nanoparticles, while the magnetic gradient contributes to the navigation of the agglomerates that are formed. Moreover, the contact forces among the aggregated nanoparticles and the wall and the Stokes drag force for each particle are considered, while only spherical particles are used in this study. In addition, gravitational forces due to gravity and the force due to buoyancy are included. Finally, Van der Walls force and Brownian motion are taken into account in the simulation. The OpenFoam platform is used for the calculation of the flow field and the uncoupled equations of particles' motion. To verify the optimal gradient magnetic fields, a covariance matrix adaptation evolution strategy (CMAES) is used in order to navigate the particles into the desired area. A desired trajectory is inserted into the computational geometry, which the particles are going to be navigated in. Initially, the CMAES optimization strategy provides the OpenFOAM program with random values of the gradient magnetic field. At the end of each simulation, the computational platform evaluates the distance between the particles and the desired trajectory. The present model can simulate the motion of particles when they are navigated by the magnetic field that is produced by the MRI device. Under the influence of fluid flow, the model investigates the effect of different gradient magnetic fields in order to minimize the distance of particles from the desired trajectory. In addition, the platform can navigate the particles into the desired trajectory with an efficiency between 80-90%. On the other hand, a small number of particles are stuck to the walls and remains there for the rest of the simulation.

Keywords: artery, drug, nanoparticles, navigation

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Authors: Isabel Brás, Artur Figueirinha, Bruno Esteves, Luísa P. Cruz-Lopes

Abstract:

The agriculture lignocellulosic by-products are receiving increased attention, namely in the search for filter materials that retain contaminants from water. These by-products, specifically almond and hazelnut shells are abundant in Portugal once almond and hazelnuts production is a local important activity. Hazelnut and almond shells have as main constituents lignin, cellulose and hemicelluloses, water soluble extractives and tannins. Along the adsorption of heavy metals from contaminated waters, water soluble compounds can leach from shells and have a negative impact in the environment. Usually, the chemical characterization of treated water by itself may not show environmental impact caused by the discharges when parameters obey to legal quality standards for water. Only biological systems can detect the toxic effects of the water constituents. Therefore, the evaluation of toxicity by biological tests is very important when deciding the suitability for safe water discharge or for irrigation applications. The main purpose of the present work was to assess the potential impacts of waters after been treated for heavy metal removal by hazelnut and almond shells adsorption systems, with short term acute toxicity tests. To conduct the study, water at pH 6 with 25 mg.L-1 of lead, was treated with 10 g of shell per litre of wastewater, for 24 hours. This procedure was followed for each bark. Afterwards the water was collected for toxicological assays; namely bacterial resistance, seed germination, Lemna minor L. test and plant grow. The effect in isolated bacteria strains was determined by disc diffusion method and the germination index of seed was evaluated using lettuce, with temperature and humidity germination control for 7 days. For aquatic higher organism, Lemnas were used with 4 days contact time with shell solutions, in controlled light and temperature. For terrestrial higher plants, biomass production was evaluated after 14 days of tomato germination had occurred in soil, with controlled humidity, light and temperature. Toxicity tests of water treated with shells revealed in some extent effects in the tested organisms, with the test assays showing a close behaviour as the control, leading to the conclusion that its further utilization may not be considered to create a serious risk to the environment.

Keywords: lignocellulosic wastes, adsorption, acute toxicity tests, risk assessment

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Authors: Fernando Araujo, Sandra Cardoso, Fátima Fonseca, Sandra Cavaca

Abstract:

A debureaucratization strategy for the Portuguese Health Service was assumed by the Executive Board of the SNS, in deep articulation with the Shared Services of the Ministry of Health. Two of the main dimensions were focused on sick leaves (SL), that transform primary health care (PHC) in administrative institutions, limiting access to patients. The self-declaration of illness (SDI) project, through the National Health Service Contact Centre (SNS24), began on May 1, 2023, and has already resulted in the issuance of more than 300,000 SDI without the need to allocate resources from the National Health Service (NHS). This political decision allows each citizen, in a maximum 2 times/year, and 3 days each time, if ill, through their own responsibility, report their health condition in a dematerialized way, and by this way justified the absence to work, although by Portuguese law in these first three days, there is no payment of salary. Using a digital approach, it is now feasible without the need to go to the PHC and occupy the time of the PHC only to obtain an SL. Through this measure, bureaucracy has been reduced, and the system has been focused on users, improving the lives of citizens and reducing the administrative burden on PHC, which now has more consultation times for users who need it. The second initiative, which began on March 1, 2024, allows the SL to be issued in emergency departments (ED) of public hospitals and in the health institutions of the social and private sectors. This project is intended to allow the user who has suffered a situation of acute urgent illness and who has been observed in an ED of a public hospital or in a private or social entity no longer need to go to PHC only to apply for the respective SL. Since March 1, 54,453 SLs have been issued, 242 in private or social sector institutions and 6,918 in public hospitals, of which 134 were in ED and 47,292 in PHC. This approach has proven to be technically robust, allows immediate resolution of problems and differentiates the performance of doctors. However, it is important to continue to qualify the proper functioning of the ED, preventing non-urgent users from going there only to obtain SL. Thus, in order to make better use of existing resources, it was operationalizing this extension of its issuance in a balanced way, allowing SL to be issued in the ED of hospitals only to critically ill patients or patients referred by INEM, SNS24, or PHC. In both cases, an intense public campaign was implemented to explain the way it works and the benefits for patients. In satisfaction surveys, more than 95% of patients and doctors were satisfied with the solutions, asking for extensions to other areas. The administrative simplification agenda of the NHS continues its effective development. For the success of this debureaucratization agenda, the key factors are effective communication and the ability to reach patients and health professionals in order to increase health literacy and the correct use of NHS.

Keywords: debureaucratization strategy, self-declaration of illness, sick leaves, SNS24

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