Search results for: microencapsulated phase change materials

Authors: Mario Chiasson, Monique Boudreau

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Problem statement: Innovation in education has become a central topic of discussion at various levels, including schools and scholarly literature, driven by the global technological advancements of Industry 4.0. This study aims to contribute to the ongoing dialogue by examining the role of innovation in transforming school culture through the reimagination of traditional structures. The study argues that such a transformation necessitates an understanding and experience of systems leadership. This paper presents the case of the Francophone South School District, where a transformative initiative created an innovative learning environment by engaging students, teachers, and community members collaboratively through eco-communities. Traditional barriers and structures in education were dismantled to facilitate this process. The research component of this paper focuses on the Intr’Appreneur project, a unique initiative launched by the district team in the New Brunswick, Canada to support a system-wide transformation towards progressive and innovative organizational models. Methods This study is part of a larger research project that focuses on the transformation of educational systems in six pilot schools involved in the Intr’Appreneur project. Due to COVID-19 restrictions, the project was downscaled to three schools, and virtual qualitative interviews were conducted with volunteer teachers and administrators. Data was collected from students, teachers, and principals regarding their perceptions of the new learning environment and experiences. The analysis process involved developing categories, establishing codes for emerging themes, and validating the findings. The study emphasizes the importance of system leadership in achieving successful transformation. Results: The findings demonstrate that school principals played a vital role in enabling system-wide change by fostering a dynamic, collaborative, and inclusive culture, coordinating and mobilizing community members, and serving as educational role models who facilitated active and personalized pedagogy among the teaching staff. These qualities align with the characteristics of Leadership 4.0 and are crucial for successful school system transformations. Conclusion: This paper emphasizes the importance of systems leadership in driving educational transformations that extend beyond pedagogical and technological advancements. The research underscores the potential impact of such a leadership approach on teaching, learning, and leading processes in Education 4.0.

Keywords: leadership, system transformation, innovation, innovative learning environment, Education 4.0, system leadership

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Authors: Naufal Ahmed, Michael Lwin

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Background: MPFL reconstructions are ideally performed with au-tografts like gracilis semitendinosus tendon, which may be associated with donor site morbidity and complications. In this case series, we have tried to use fiber tape, which avoids the above complications and also keeps the graft virgin. This kind of synthetic graft has been used successfully in rotator cuffs and ACJ reconstructions with good results. Materials and methods: It was a retrospective data analysis of 45 patients who underwent this procedure from 2014-2020 under a single consultant in a DGH . These patiens have been followed up at 6 weeks, 6 months, 1 year, and 1 ½ years with clinical assessment and KOOS scores. We compared the results with the NJR and also with the Belgium report and was found to be satisfactory and comparable with them. Surgical technique : We used Arthrex fiber tape for the reconstruction of MPFL . Initially, two parallel holes drilled over sup aspect of the patella with help of an image intensifier, and then fiber wire passed through them from the medial to the lateral side and back to the medial side. The fiber wire was attached to the schottle point on the femoral side, giving a good extra articular internal brac-ing to the MPFL. All patients were scoped before the procedure, and the final tightening over the femoral side was done directly under vision to see the position of the patella. Results: We had 45 MPFL reconstructions along with 4 additional procedures 1 ACLR, 2 ACL REPAIR, 1 TTT advancement ( revision MPFL ). There were 14 males and 31 females, and their average age was 25 (13-55 ). We did not have any donor site morbidity, no infection, no fractures, no recurrent dislocations, no reoperations yet. Conclusion: Fiber tape is a feasible and appropriate option for MPFL reconstruction. We haven’t seen any re -operation in our 5 year follow up. This technique avoids the use of autograft, which can be used in the future if needed for revision surgeries. We don’t lose anything by following this simple novel technique.

Keywords: arthroscopy, fibertape, MPFL reconstruction, recurrent patella dislocation

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Authors: Iyd Eqqab Maree, Habil Jurgen Bast

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Vibration control of machines and structures incorporating viscoelastic materials in suitable arrangement is an important aspect of investigation. The use of viscoelastic layers constrained between elastic layers is known to be effective for damping of flexural vibrations of structures over a wide range of frequencies. The energy dissipated in these arrangements is due to shear deformation in the viscoelastic layers, which occurs due to flexural vibration of the structures. Multilayered cantilever sandwich beam like structures can be used in aircrafts and other applications such as robot arms for effective vibration control. These members may experience parametric instability when subjected to time dependant forces. The theory of dynamic stability of elastic systems deals with the study of vibrations induced by pulsating loads that are parametric with respect to certain forms of deformation. The purpose of the present work is to investigate the dynamic stability of a three layered symmetric sandwich beam (Drone Aircraft wings ) subjected to an end periodic axial force . Equations of motion are derived using finite element method (MATLAB software). It is observed that with increase in core thickness parameter fundamental buckling load increases. The fundamental resonant frequency and second mode frequency parameter also increase with increase in core thickness parameter. Fundamental loss factor and second mode loss factor also increase with increase in core thickness parameter. Increase in core thickness parameter enhances the stability of the beam. With increase in core loss factor also the stability of the beam enhances. There is a very good agreement of the experimental results with the theoretical findings.

Keywords: steel cantilever beam, viscoelastic material core, loss factor, transition region, MATLAB R2011a

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Authors: David Tennison

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In the wake of the Covid-19 pandemic, a new chronic illness emerged onto the global stage: Long Covid. Long Covid presents with several symptoms commonly seen in other poorly-understood illnesses, such as fibromyalgia (FM) and myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS). However, while Long Covid has swiftly become a recognised illness, FM and ME/CFS are still seen as contested, which impacts patient care and healthcare experiences. This study aims to examine what the differences are between Long Covid and FM; and if the Long Covid case can provide guidance for how to address the healthcare challenge of contested illnesses. To address this question, this study performed comprehensive research into the history of FM; our current biomedical understanding of it; and available healthcare interventions (within the context of the UK NHS). Analysis was undertaken of the stigma and stereotypes around FM, and a comparison made between FM and the emerging Long Covid literature, along with the healthcare response to Long Covid. This study finds that healthcare for chronic contested illnesses in the UK is vastly insufficient - in terms of pharmaceutical and holistic interventions, and the provision of secondary care options. Interestingly, for Long Covid, many of the treatment suggestions are pulled directly from those used for contested illnesses. The key difference is in terms of funding and momentum – Long Covid has generated exponentially more interest and research in a short time than there has been in the last few decades of contested illness research. This stands to help people with FM and ME/CFS – for example, research has recently been funded into “brain fog”, a previously elusive and misunderstood symptom. FM is culturally regarded as a “women’s disease” and FM stigma stems from notions of “hysteria”. A key finding is that the idea of FM affecting women disproportionally is not reflected in modern population studies. Emerging data on Long Covid also suggests a slight leaning towards more female patients, however it is less feminised, potentially due to it emerging in the global historical moment of the pandemic. Another key difference is that FM is rated as an extremely low-prestige illness by healthcare professionals, while it was in large part due to the advocacy of affected healthcare professionals that Long Covid was so quickly recognised by science and medicine. In conclusion, Long Covid (and the risk of future pandemics and post-viral illnesses) highlight a crucial need for implementing new, and reinforcing existing, care networks for chronic illnesses. The difference in how contested illnesses like FM, and new ones like Long Covid are treated have a lot to do with the historical moment in which they emerge – but cultural stereotypes, from within and without medicine, need updating. Particularly as they contribute to disease stigma that causes genuine harm to patients. However, widespread understanding and acceptance of Long Covid could help fight contested illness stigma, and the attention, funding and research into Long Covid may actually help raise the profile of contested illnesses and uncover answers about their symptomatology.

Keywords: long COVID, fibromyalgia, myalgic encephalomyelitis, chronic fatigue syndrome, NHS, healthcare, contested illnesses, chronic illnesses, COVID-19 pandemic

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Authors: Shabnam Najafi, Metin Turkay

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Network design problem (NDP) is used to determine the set of optimal values for certain pre-specified decision variables such as capacity expansion of nodes and links by optimizing various system performance measures including safety, congestion, and accessibility. The designed transportation network should improve objective functions defined for the system by considering the route choice behaviors of network users at the same time. The NDP studies mostly investigated the random demand and route selection constraints separately due to computational challenges. In this work, we consider both random demand and route selection constraints simultaneously. This work presents a nonlinear stochastic model for land use and road network design problem to address the development of different functional zones in urban areas by considering both cost function and air pollution. This model minimizes cost function and air pollution simultaneously with random demand and stochastic route selection constraint that aims to optimize network performance via road capacity expansion. The Bureau of Public Roads (BPR) link impedance function is used to determine the travel time function in each link. We consider a city with origin and destination nodes which can be residential or employment or both. There are set of existing paths between origin-destination (O-D) pairs. Case of increasing employed population is analyzed to determine amount of roads and origin zones simultaneously. Minimizing travel and expansion cost of routes and origin zones in one side and minimizing CO emission in the other side is considered in this analysis at the same time. In this work demand between O-D pairs is random and also the network flow pattern is subject to stochastic user equilibrium, specifically logit route choice model. Considering both demand and route choice, random is more applicable to design urban network programs. Epsilon-constraint is one of the methods to solve both linear and nonlinear multi-objective problems. In this work epsilon-constraint method is used to solve the problem. The problem was solved by keeping first objective (cost function) as the objective function of the problem and second objective as a constraint that should be less than an epsilon, where epsilon is an upper bound of the emission function. The value of epsilon should change from the worst to the best value of the emission function to generate the family of solutions representing Pareto set. A numerical example with 2 origin zones and 2 destination zones and 7 links is solved by GAMS and the set of Pareto points is obtained. There are 15 efficient solutions. According to these solutions as cost function value increases, emission function value decreases and vice versa.

Keywords: epsilon-constraint, multi-objective, network design, stochastic

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Authors: Tahani Amutairi, Paul May, Neil Allan

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Many properties of semiconductor materials (mechanical, electronic, magnetic, and optical) can be significantly modified by introducing a point defect. Diamond offers extraordinary properties as a semiconductor, and doping seems to be a viable method of solving the problem associated with the fabrication of diamond-based electronic devices in order to exploit those properties. The dopants are believed to play a significant role in reducing the energy barrier to conduction and controlling the mobility of the carriers and the resistivity of the film. Although it has been proven that the n-type diamond semiconductor can be obtained with phosphorus doping, the resulting ionisation energy and mobility are still inadequate for practical application. Theoretical studies have revealed that this is partly because the effects of the many phosphorus atoms incorporated in the diamond lattice are compensated by acceptor states. Using spin-polarised hybrid density functional theory and a supercell approach, we explored the effects of bonding one N atom to a P in adjacent substitutional sites in diamond. A range of hybrid functional, including HSE06, B3LYP, PBE0, PBEsol0, and PBE0-13, were used to calculate the formation, binding, and ionisation energies, in order to explore the solubility and stability of the point defect. The equilibrium geometry and the magnetic and electronic structures were analysed and presented in detail. The defect introduces a unique reconstruction in a diamond where one of the C atoms coordinated with the N atom involved in the elongated C-N bond and creates a new bond with the P atom. The simulated infrared spectra of phosphorus-nitrogen defects were investigated with different supercell sizes and found to contain two sharp peaks at the edges of the spectrum, one at a high frequency 1,379 cm⁻¹ and the second appearing at the end range, 234 cm⁻¹, as obtained with the largest supercell (216).

Keywords: DFT, HSE06, B3LYP, PBE0, PBEsol0, PBE0-13

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Authors: Mohammed Ghazwani, Shyma Ali Alshahrani, Zahra Abdu Yousef, Taif Torki Asiri, Ghofran Abdur Rahman, Asma Ali Alshahrani, Umme Hani

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Background and introduction: Piroxicam is a nonsteroidal anti-inflammatory drug characterized by low solubility-high permeability used to reduce pain, swelling, and joint stiffness from arthritis. Hydrotropes are a class of compounds that normally increase the aqueous solubility of insoluble solutes. Aim: The objective of the present research study was to formulate and optimize Piroxicam hydrotropic starch gel using sodium salicylate, sodium benzoate as hydrotropic salts, and potato starch for topical application. Materials and methods: The prepared Piroxicam hydrotropic starch gel was characterized for various physicochemical parameters like drug content estimation, pH, tube extrudability, and spreadability; all the prepared formulations were subjected to in-vitro diffusion studies for six hours in 100 ml phosphate buffer (pH 7.4) and determined gel strength. Results: All formulations were found to be white opaque in appearance and have good homogeneity. The pH of formulations was found to be between 6.9-7.9. Drug content ranged from 96.8%-99.4.5%. Spreadability plays an important role in patient compliance and helps in the uniform application of gel to the skin as gels should spread easily; F4 showed a spreadability of 2.4cm highest among all other formulations. In in vitro diffusion studies, extrudability and gel strength were good with F4 in comparison with other formulations; hence F4 was selected as the optimized formulation. Conclusion: Isolated potato starch was successfully employed to prepare the gel. Hydrotropic salt sodium salicylate increased the solubility of Piroxicam and resulted in a stable gel, whereas the gel prepared using sodium benzoate changed its color after one week of preparation from white to light yellowish. Hydrotropic potato starch gel proposed a suitable vehicle for the topical delivery of Piroxicam.

Keywords: Piroxicam, potato starch, hydrotropic salts, hydrotropic starch gel

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Authors: Shu-Lien Chou, Chung-Feng Liu

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Self-health management of chronic illnesses plays an important part in chronic illness treatments. However, various kinds of health information (health education materials) which government or healthcare institutions provide for patients may not achieve the expected outcome. One of the critical reasons affecting patients’ use intention could be patients’ perceived Information overload regarding the health information. This study proposed an extended model of Theory of Planned Behavior, which integrating perceived information overload as another construct to explore patients’ use intention of the health information for self-health management. The independent variables are attitude, subject norm, perceived behavior control and perceived information overload while the dependent variable is behavior intention to use the health information. The cross-sectional study used a structured questionnaire for data collection, focusing on the chronic patients with coronary artery disease (CAD), who are the potential users of the health information, in a medical center in Taiwan. Data were analyzed using descriptive statistics of the basic information distribution of the questionnaire respondents, and the Partial Least Squares (PLS) structural equation model to study the reliability and construct validity for testing our hypotheses. A total of 110 patients were enrolled in this study and 106 valid questionnaires were collected. The PLS analysis result indicates that the patients’ perceived information overload of health information contributes the most critical factor influencing the behavioral intention. Subjective norm and perceived behavioral control of TPB constructs had significant effects on patients’ intentions to use health information also, whereas the attitude construct did not. This study demonstrated a comprehensive framework, which extending perceived information overload into TPB model to predict patients’ behavioral intention of using heath information. We expect that the results of this study will provide useful insights for studying health information from the perspectives of academia, governments, and healthcare providers.

Keywords: chronic patients, health information, information overload, theory of planned behavior

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Authors: Saeideh Soltanmohammadlou, Pilar M Guerrieri, Amir Kianfar, Sara Sadeghian, Yasaman Nafezi, Emily Irvin

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Architecture is rooted in the experiences of the residents in a place. Its foundations are based on needs and circumstances of each territory in terms of climate, available materials, economics and governmental policies, and cultural ideals and ideas of the people that live there. The architectural history of Iran echoes these architectural origins and has revealed certain trends reflecting this territory and culture. However, in recent years, new architectural patterns are developing that diverge from what has previously been considered classic forms of Iranian architecture. This article investigates architectural elements that make up the architecture created by religious minorities after the Safavid dynasty (one of the most significant ruling dynasties of Iran (from 1501 to 1736) in Iranian cities: Isfahan, Tabriz, Kerman, and Uremia. Similarities and differences are revealed between the architecture that composes neighborhoods of religious minorities in Iran and common national architectural trends in each era after this dynasty. This dynasty is specific as a point of reference in this article because Islam was identified as the state religion of Iran during this era. This decision changed the course of architecture in the country to incorporate religious motifs and meanings. The study associated with this article was conducted as a survey that sought to find links between architecture of religious minorities with Iranian national architecture. Interestingly, a merging of architectural forms and trends occur as immigrants interact with Iranian Islamic meanings. These observations are significant within the context of modern architecture around the world and within Western discourse because what are considered religious minorities in Iran are the dominant religions in Western nations. This makes Iran’s architecture particularly unique as it creates a kind of inverse relationship, than that of Western nations, to the ways in which religion influences architectural history.

Keywords: architecture, ethnic architecture, national architecture, religion architecture

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Authors: Elizabeth Crafton, Donald Ott, Teresa Cutright

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Harmful algal blooms (HABs), more notably cyanobacteria-dominated HABs, compromise water quality, jeopardize access to drinking water and are a risk to public health and safety. HABs are representative of ecosystem imbalance largely caused by environmental changes, such as eutrophication, that are associated with the globally expanding human population. Cyanobacteria-dominated HABs are anticipated to increase in frequency, magnitude, and are predicted to plague a larger geographical area as a result of climate change. The weather pattern is important as storm-driven, pulse-input of nutrients have been correlated to cyanobacteria-dominated HABs. The mobilization of aqueous and particulate nutrients and the response of the phytoplankton community is an important relationship in this complex phenomenon. This relationship is most apparent in high-impact areas of adequate sunlight, > 20ᵒC, excessive nutrients and quiescent water that corresponds to ideal growth of HABs. Typically the impact of particulate phosphorus is dismissed as an insignificant contribution; which is true for areas that are not considered high-impact. The objective of this study was to assess the impact of a simulated storm-driven, pulse-input of reactive phosphorus and the response of three different cyanobacteria assemblages (~5,000 cells/mL). The aqueous and particulate sources of phosphorus and changes in HAB were tracked weekly for 4 weeks. The first cyanobacteria composition consisted of Planktothrix sp., Microcystis sp., Aphanizomenon sp., and Anabaena sp., with 70% of the total population being non-diazotrophic and 30% being diazotrophic. The second was comprised of Anabaena sp., Planktothrix sp., and Microcystis sp., with 87% diazotrophic and 13% non-diazotrophic. The third composition has yet to be determined as these experiments are ongoing. Preliminary results suggest that both aqueous and particulate sources are contributors of total reactive phosphorus in high-impact areas. The results further highlight shifts in the cyanobacteria assemblage after the simulated pulse-input. In the controls, the reactors dosed with aqueous reactive phosphorus maintained a constant concentration for the duration of the experiment; whereas, the reactors that were dosed with aqueous reactive phosphorus and contained soil decreased from 1.73 mg/L to 0.25 mg/L of reactive phosphorus from time zero to 7 days; this was higher than the blank (0.11 mg/L). Suggesting a binding of aqueous reactive phosphorus to sediment, which is further supported by the positive correlation observed between total reactive phosphorus concentration and turbidity. The experiments are nearly completed and a full statistical analysis will be completed of the results prior to the conference.

Keywords: Anabaena, cyanobacteria, harmful algal blooms, Microcystis, phosphorous, response surface methodology

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Authors: Diego Romero, Fabio Rojas, J. Alejandro Urrego

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The sounding rockets are aerospace vehicles that were developed in the mid-20th century, and Colombia has been involved in research that was carried out with the aim of innovating with this technology. The rockets are university research programs with the collaboration of the local government, with a simple strategy, develop and reduce the greatest costs associated with the production of a kind type of technology. In this way, in this document presents the failure analysis of a solid rocket motor, with the real compatibly to reach the thermosphere with a low-cost fuel. This solid rocket motor is the latest development of the Uniandes Aerospace Project (PUA for its Spanish acronym), an undergraduate and postgraduate research group at Universidad de los Andes (Bogotá, Colombia), dedicated to incurring in this type of technology. This motor has been carried out on Candy-type solid fuel, which is a compound of potassium nitrate and sorbitol, and the investigation has allowed the production of solid motors powerful enough to reach space, and which represents a unique technological advance in Latin America and an important development in experimental rocketry.To outline the main points the explosion in a static test is an important to explore and demonstrate the ways to develop technology, methodologies, production and manufacturing, being a solid rocket motor with 30 kN of thrust. In conclusion, this analysis explores different fields such as: design, manufacture, materials, production, first fire and more, with different engineering tools with principal objective find root failure. Following the engineering analysis methodology, was possible to design a new version of motor, with learned lessons new manufacturing specification, therefore, when publishing this project, it is intended to be a reference for future research in this field and benefit the industry.

Keywords: candy propellant, candy rockets, explosion, failure analysis, static test, solid rocket motor

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Authors: Rommila Chandra, Harshika Choudhary

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The value of integrated, participatory, and community based sustainable development strategies is eminent, but in practice, it still remains fragmentary and often leads to short-lived results. Despite the global presence of climate change, its impacts are felt differently by different communities based on their vulnerability. The developing countries have the low adaptive capacity and high dependence on environmental variables, making them highly susceptible to outmigration and poverty. We need to understand how to enable these approaches, taking into account the various governmental and non-governmental stakeholders functioning at different levels, to deliver long-term socio-economic and environmental well-being of local communities. The research assessed the financial and natural vulnerability of Himalayan networks, focusing on their potential to adapt to various changes, through accessing their perceived reactions and local knowledge. The evaluation was conducted by testing indices for vulnerability, with a major focus on indicators for adaptive capacity. Data for the analysis were collected from the villages around Govind National Park and Wildlife Sanctuary, located in the Indian Himalayan Region. The villages were stratified on the basis of connectivity via road, thus giving two kinds of human settlements connected and isolated. The study focused on understanding the complex relationship between outmigration and the socio-cultural sentiments of local people to not abandon their land, assessing their adaptive capacity for livelihood opportunities, and exploring their contribution that integrated participatory methodologies can play in delivering sustainable development. The result showed that the villages having better road connectivity, access to market, and basic amenities like health and education have a better understanding about the climatic shift, natural hazards, and a higher adaptive capacity for income generation in comparison to the isolated settlements in the hills. The participatory approach towards environmental conservation and sustainable use of natural resources were seen more towards the far-flung villages. The study helped to reduce the gap between local understanding and government policies by highlighting the ongoing adaptive practices and suggesting precautionary strategies for the community studied based on their local conditions, which differ on the basis of connectivity and state of development. Adaptive capacity in this study has been taken as the externally driven potential of different parameters, leading to a decrease in outmigration and upliftment of the human environment that could lead to sustainable livelihood development in the rural areas of Himalayas.

Keywords: adaptive capacity, Indian Himalayan region, participatory, sustainable livelihood development

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Authors: Alina Smalinskiene Janina Petkeviciene, Jurate Klumbiene, Vilma Kriaucioniene, Vaiva Lesauskaite

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The worldwide prevalence of obesity has been increasing dramatically in the last few decades, and Lithuania is no exception. In 2012, every fifth adult (19% of men and 20.5 % of women) was obese and every third was overweight Association studies have highlighted the influence of SNPs in obesity, with particular focus on FTO rs9939609. Thus far, no data on the possible association of this SNP to obesity in the adult Lithuanian population has been reported. Here, for the first time, we demonstrate an association between the FTO rs9939609 homozygous AA genotype and increased BMI when compared to homozygous TT. Furthermore, a positive association was determined between the FTO rs9939609 variant and risk of metabolic syndrome. Background: This study aimed to examine the associations between the fat mass and obesity associated (FTO) gene rs9939609 variant with obesity and metabolic syndrome in Lithuanian adult population. Materials and Methods: A cross-sectional health survey was carried out in randomly selected municipalities of Lithuania. The random sample was obtained from lists of 25–64 year-old inhabitants. The data from 1020 subjects were analysed. The rs9939609 SNP of the FTO gene was assessed using TaqMan assays (Applied Biosystems, Foster City, CA, USA). The Applied Biosystems 7900HT Real-Time Polymerase Chain Reaction System was used for detecting the SNPs. Results: The carriers of the AA genotype had the highest mean values of BMI and waist circumference (WC) and the highest risk of obesity. Interactions ‘genotype x age’ and ‘genotype x physical activity’ in determining BMI and WC were shown. Neither lipid and glucose levels, nor blood pressure were associated with the rs9939609 independently of BMI. In the age group of 25-44 years, association between the FTO genotypes and metabolic syndrome was found. Conclusion: The FTO rs9939609 variant was significantly associated with BMI and WC, and with the risk of obesity in Lithuanian population. The FTO polymorphism might have a greater influence on weight status in younger individuals and in subjects with a low level of physical activity.

Keywords: obesity metabolic syndrome, FTO gene, polymorphism, Lithuania

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Authors: Abdulfattah A. Q. Alwah, Amal Al‑Attar, Sumyah M. Al-Fanini, Ellen Fetzer

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Cultural landscapes enhance the spiritual relationship between people and their environment. They represent civilized evidence of peoples' interaction with nature and the exploitation of its resources to build their civilization. Yemeni urban and rural environments are rich in many cultural landscape elements that reflect the ingenuity of Yemeni people in interacting with nature. Yemen's mountain cities and villages appear in harmony with mountains, with vertical tower building patterns, local building materials, and unique architectural and urban elements and features. Such cities and villages are still full of life today, such as the cities of Taiz, Ibb, Lahj, and historical Jableh and hundreds of mountain villages in the provinces of the mountainous highlands. The cultivated mountain terraces reflect the ability of Yemenis to create arable areas in the tall mountains and to use successful means of irrigation and rainwater drainage. Unfortunately, there is a severe shortage of research studies that discuss the cultural landscapes in Yemen and the mechanisms for their preservation. Therefore, this study aimed to shed light on the types of mountain cultural landscapes in Yemen and discuss the means of their preservation. The study achieved its objectives through a theoretical review of available studies and field visits to some sites in Ibb, Jableh, and Taiz cities. The study highlighted the human contribution to these sites and elements and showed the Yemenis’ skills in adapting to nature and benefiting from it ideally. This study can guide the competent authorities to assess, develop, and protect cultural landscape sites in Yemen.

Keywords: civilization, urban environment, Yemeni mountain architecture, human heritage conservation, cultural identity

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Authors: Qian Yi Ooi

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At present, airfoil parameters are still designed and optimized according to the scale of conventional aircraft, and there are still some slight deviations in terms of scale differences. However, insufficient parameters or poor surface mesh quality is likely to occur if these small deviations are embedded in a future civil aircraft with a size that is quite different from conventional aircraft, such as a blended-wing-body (BWB) aircraft with future potential, resulting in large deviations in geometric similarity in computational fluid dynamics (CFD) simulations. To avoid this situation, the study on the CFD calculation on the geometric similarity of airfoil parameters and the quality of the surface mesh is conducted to obtain the ability of different parameterization methods applied on different airfoil scales. The research objects are three airfoil scales, including the wing root and wingtip of conventional civil aircraft and the wing root of the giant hybrid wing, used by three parameterization methods to compare the calculation differences between different sizes of airfoils. In this study, the constants including NACA 0012, a Reynolds number of 10 million, an angle of attack of zero, a C-grid for meshing, and the k-epsilon (k-ε) turbulence model are used. The experimental variables include three airfoil parameterization methods: point cloud method, B-spline curve method, and class function/shape function transformation (CST) method. The airfoil dimensions are set to 3.98 meters, 17.67 meters, and 48 meters, respectively. In addition, this study also uses different numbers of edge meshing and the same bias factor in the CFD simulation. Studies have shown that with the change of airfoil scales, different parameterization methods, the number of control points, and the meshing number of divisions should be used to improve the accuracy of the aerodynamic performance of the wing. When the airfoil ratio increases, the most basic point cloud parameterization method will require more and larger data to support the accuracy of the airfoil’s aerodynamic performance, which will face the severe test of insufficient computer capacity. On the other hand, when using the B-spline curve method, average number of control points and meshing number of divisions should be set appropriately to obtain higher accuracy; however, the quantitative balance cannot be directly defined, but the decisions should be made repeatedly by adding and subtracting. Lastly, when using the CST method, it is found that limited control points are enough to accurately parameterize the larger-sized wing; a higher degree of accuracy and stability can be obtained by using a lower-performance computer.

Keywords: airfoil, computational fluid dynamics, geometric similarity, surface mesh quality

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Authors: Oyetunji John Adenuga

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This study on the comparative analysis of the performance of teachers in private and public schools was carried out in Ibadan North West Local Government Area of Oyo State. This study examined the justification for the claim that there is difference in the performance of teachers in private and public primary schools and at the same time identified factors responsible for the difference in the performance of these teachers. A descriptive survey research design was used for the study. Data generated were analysed using t-test and regression analysis. The findings of the study revealed that there is significant difference in the performance of teachers in private and private primary schools in Ibadan North West Local Government Area of Oyo State (t=64.09; df=459; p,.05). The findings also revealed that the method of teaching in private primary schools is significantly different from the method of teaching in public primary schools in Ibadan North West Local Government Area of Oyo State (t=73.08; df=459; p,.05). Findings revealed that school leadership and management have significant contribution on the performance of private and public primary school teachers in Ibadan North West Local Area of Oyo State. Based on the finding, the following recommendations were made: Primary school teachers need to be motivated and rewarded for excellent performance. Primary schools should be properly equipped with teaching-aid facilities, laboratories and libraries. Government should use the findings of this study to improve on teaching materials provided to the primary school teachers in Nigeria. Public primary schools should be designed by education planners, administrators and government. Headmasters, proprietors and teachers of primary schools should look inward and give a performance appraisal and evaluation of themselves form time to time based on subject they taught. Finally, school administrators should be conscious of the way they manage the teachers in schools not only in informal situations but also in formal settings.

Keywords: private education, public education, school leadership, school management, teachers performance

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Authors: Shoba Bandi-Rao

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The lack of college readiness is one of the major contributors to low graduation rates at community colleges, especially among educationally and financially disadvantaged students. About 45% of underprepared high school graduates are required to complete ‘remedial’ reading/writing courses before they can begin taking college-level courses. Mobile apps present ‘bite-size’ learning materials that can be useful for practicing certain literacy skills, such as vocabulary learning. The convenience of mobile phones is ideal for a majority of students at community colleges who hold full or part-time jobs. Mobile apps allow students to learn during small ‘chunks’ of time available to them outside of the class—during subway commute, between classes, etc. Learning with mobile apps is a relatively new area in research, and their effectiveness for learning new words has been inconclusive. Using Mishra & Koehler’s TPCK theoretical framework, this study explored the effectiveness of the mobile app (Quizlet) for learning one hundred common college-level words in ‘remedial’ writing class over one semester. Each week, before coming to class, students studied a list of 10-15 words presented in context within sentences. Students came across these words in the article they read in class making their learning more meaningful. A pre and post-test measured the number of words students knew, learned and remembered. Statistical analysis shows that students performed better by 41% on the post-test indicating that the mobile app was helpful for learning words. Students also completed a short survey each week that sought to determine the amount of time students spent on the vocabulary app. A positive correlation was found between the amount of time spent on the mobile app and the number of words learned. The goal of this research is to capitalize on the convenience of smartphones to (1) better prepare them for college-level course work, and (2) contribute to current literature on mobile learning.

Keywords: mobile learning, vocabulary learning, literacy skills, Quizlet

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Authors: Athanasia Eirini Zarkadi, Despoina Balli, Olga Elpis Kolokitha

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Objective: Impacted maxillary canines are a frequent condition and a common reason for patients seeking orthodontic treatment. Their simultaneous presence with dental anomalies raises a question about their possible connection. The aim of this study was to investigate the association of maxillary impacted canines with dental anomalies. Materials and Methods: Files of 874 patients from an orthodontic private practice in Greece were evaluated for the presence of maxillary impacted canines. From this sample, a group of 97 patients (39 males and 58 females) with at least one impacted maxillary canine were selected and consisted of the study group (canine impaction group) of this study. This group was compared to a control group of 97 patients (42 males and 55 females) that was created by random selection from the initial sample without maxillary canine impaction. The impaction diagnosis was made from the panoramic radiographs and confirmed from the surgery. The association between maxillary canine impaction and dental anomalies was examined with the chi-square test. A classification tree was created to further investigate the relations between impaction and dental anomalies. The reproducibility of diagnoses was assessed by re-examining the records of 25 patients two weeks after the first examination. Results: The found associated anomalies were cone-shaped upper lateral incisors and infraocclusion of deciduous molars. There is a significant increase in the prevalence of 12,4% of distal displacement of the unerupted mandibular second premolar in the canine impaction group compared to the control group that was 7,2%. The classification tree showed that the presence of a cone-shaped maxillary lateral incisor gave rise to the probability of an impacted canine to 83,3%. Conclusions: The presence of cone-shaped maxillary lateral incisors and infraocclusion of deciduous molars can be considered valuable early risk indicators for maxillary canine impaction.

Keywords: cone-shaped maxillary lateral incisors, dental anomalies, impacted canines, infraoccluded deciduous molars

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Authors: Narjis Kahtoon

Abstract:

The issue of the wage discrimination on the basis of gender and social problem has been a significant research problem for several decades. Whereas lots of have explored reasons for the persistence of an inequality in the wages of male and female, none has successfully explained away the entire differentiation. The wage discrimination on the basis of gender and social problem of working women is a global issue. Although inequality in political and economic and social make-up of countries all over the world, the gender wage discrimination, and social constraint is present. The aim of the research is to examine the gender wage discrimination and social constraint from an international perspective and to determine whether any pattern exists among cultural dimensions of a country and the man and women remuneration gap in Readymade Garment Sector of Pakistan. Population growth rate is significant indicator used to explain the change in population and play a crucial point in the economic development of a country. In Pakistan, readymade garment sector consists of small, medium and large sized firms. With an estimated 30 percent of the workforce in textile- Garment is females’. Readymade garment industry is a labor intensive industry and relies on the skills of individual workers and provides highest value addition in the textile sector. In the Garment sector, female workers are concentrated in poorly paid, labor-intensive down-stream production (readymade garments, linen, towels, etc.), while male workers dominate capital- intensive (ginning, spinning and weaving) processes. Gender wage discrimination and social constraint are reality in Pakistan Labor Market. This research allows us not only to properly detect the size of gender wage discrimination and social constraint but to also fully understand its consequences in readymade garment sector of Pakistan. Furthermore, research will evaluated this measure for the three main clusters like Lahore, Karachi, and Faisalabad. These data contain complete details of male and female workers and supervisors in the readymade garment sector of Pakistan. These sources of information provide a unique opportunity to reanalyze the previous finding in the literature. The regression analysis focused on the standard 'Mincerian' earning equation and estimates it separately by gender, the research will also imply the cultural dimensions developed by Hofstede (2001) to profile a country’s cultural status and compare those cultural dimensions to the wage inequalities. Readymade garment of Pakistan is one of the important sectors since its products have huge demand at home and abroad. These researches will a major influence on the measures undertaken to design a public policy regarding wage discrimination and social constraint in readymade garment sector of Pakistan.

Keywords: gender wage differentials, decomposition, garment, cultural

Procedia PDF Downloads 195

Authors: A. Aboubakr, E. Fehling, S. A. Mourad, M. Omar

Abstract:

Wind energy is one of the most effective renewable sources especially offshore wind energy although offshore wind technology is more costly to produce. It is well known that offshore wind energy can potentially be very cheap once infrastructure and researches improve. Laterally, the trend is to construct offshore wind energy to generate the electricity form wind. This leads to intensive research in order to improve the infrastructures. Offshore wind energy is the construction of wind farms in bodies of water to generate electricity from wind. The most important part in offshore wind turbine structure is the foundation and its connection with the wind tower. This is the main difference between onshore and offshore structures. Grouted connection between the foundation and the wind tower is the most important part of the building process when constructing wind offshore turbines. Most attention should be paid to the actual grout connection as this transfers the loads safely from tower to foundations and the soil also. In this paper, finite element analyses have been carried out for studying the behaviour of offshore grouted connection for wind turbine structures. ATENA program have been used for non-linear analysis simulation of the real structural behavior thus demonstrating the crushing, cracking, contact between the two materials and steel yielding. A calibration of the material used in the simulation has been carried out assuring an accurate model of the used material by ATENA program. This calibration was performed by comparing the results from the ATENA program with experimental results to validate the material properties used in ATENA program. Three simple patch test models with different properties have been performed. The research is concluded with a result that the calibration showing a good agreement between the ATENA program material behaviors and the experimental results.

Keywords: grouted connection, 3D modeling, finite element analysis, offshore wind energy turbines, stresses

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Authors: Muhammed Jamiu Mustapha, Jamiu Folarin, Stephen Obiri Agyei, Rasheed Ademola Adebiyi, Mutiu Iyanda Lasisi

Abstract:

The role of the media in political discourse cannot be overemphasized as they form an important part of societal development. The media institution is considered the fourth estate of the realm because it serves as a check and balance to the arms of government (Executive, Legislature and Judiciary) especially in a democratic setup, and makes public office holders accountable to the people. They scrutinize the political candidates and conduct a holistic analysis of the achievement of the government in order to make the people’s representative accountable to the electorates. The media in Nigeria play a seminal role in shaping how people vote during elections. Newspaper headlines are catchy phrases that easily capture the attention of the audience and call them (audience) to action. Research conducted on newspaper headlines looks at the linguistic aspect and how the tenses used has a resultant effect on peoples’ attitude and behaviour. Communication scholars have also conducted studies that interrogate whether newspaper headlines influence peoples' voting patterns and decisions. Propaganda and negative stories about political opponents are stapling features in electioneering campaigns. Nigerian newspaper readers have the characteristic of scanning newspaper headlines. And the question is whether politicians effectively have played into this tendency to brand opponents negatively, based on half-truths and inadequate information. This study illustrates major trends in the Nigerian political landscape looking at the past four presidential elections and frames the progress of the research in the extant body of political propaganda research in Africa. The study will use the quantitative content analysis of newspaper headlines from 2007 to 2019 to be able to ascertain whether newspaper headlines had any effect on the election results of the presidential elections during these years. This will be supplemented by Key Informant Interviews of political scientists or experts to draw further inferences from the quantitative data. Drawing on newspaper headlines of selected newspapers in Nigeria that have a political propaganda angle for the presidential elections, the analysis will correspond to and complements extant descriptions of how the field of political propaganda has been developed in Nigeria, providing evidence of four presidential elections that have shaped Nigerian politics. Understanding the development of the behavioural change of the electorates provide useful context for trend analysis in political propaganda communication. The findings will contribute to how newspaper headlines are used partly or wholly to decide the outcome of presidential elections in Nigeria.

Keywords: newspaper headlines, political propaganda, presidential elections, trend analysis

Procedia PDF Downloads 217

Authors: Neal Rupani

Abstract:

Background: A surgical trainee has limited learning opportunities in the operating room in order to gain an ever-increasing standard of surgical skill, competency, and proficiency. These opportunities continue to decline due to numerous factors such as the European Working Time Directive and increasing requirement for service provision. It is therefore imperative to obtain the highest educational value from each educational opportunity. A measure that has yet to be validated in England on surgical trainees called the Operating Room Educational Environment Measure (OREEM) has been developed to identify and evaluate each component of the educational environment with a view to steer future change in optimising educational events in theatre. Aims: The aims of the study are to assess the reliability of the OREEM within England and to evaluate the surgical trainee’s objective perspective of the current operating room educational environment within one region within England. Methods: Using a quantitative study approach, data was collected over one month from surgical trainees within Health Education Thames Valley (Oxford) using an online questionnaire consisting of demographic data, the OREEM, a global satisfaction score. Results: 140 surgical trainees were invited to the study, with an online response of 54 participants (response rate = 38.6%). The OREEM was shown to have good internal consistency (α = 0.906, variables = 40) and unidimensionality, along with all four of its subgroups. The mean OREEM score was 79.16%. The areas highlighted for improvement predominantly focused on improving learning opportunities (average subscale score = 72.9%) and conducting pre- and post-operative teaching (average score = 70.4%). The trainee perception is most satisfactory for the level of supervision and workload (average subscale score = 82.87%). There was no differences found between gender (U = 191.5, p = 0.535) or type of hospital (U = 258.0, p = 0.099), but the learning environment was favoured towards senior trainees (U = 223.5, p = 0.017). There was strong correlation between OREEM and the global satisfaction score (r = 0.755, p<0.001). Conclusions: The OREEM was shown to be reliable in measuring the educational environment in the operating room. This can be used to identify potentially modifiable components for improvement and as an audit tool to ensure high standards are being met. The current perception of the education environment in Health Education Thames Valley is satisfactory, and modifiable internal and external factors such as reducing service provision requirements, empowering trainees to plan lists, creating a team-working ethic between all personnel, and using tools that maximise learning from each operation have been identified to improve learning in the future. There is a favourable attitude to use of such improvement tools, especially for those currently dissatisfied.

Keywords: education environment, surgery, post-graduate education, OREEM

Procedia PDF Downloads 170

Authors: Suresh Kumar Verma, Jugal Kishore Das, Ealisha Jha, Mrutyunjay Suar, SKS Parashar

Abstract:

In recent years nanoforms of inorganic metallic oxides has attracted a lot of interest due to their small size and significantly improved physical, chemical and biological properties compared to their molecular precursor. Some of the inorganic materials such as TiO2, ZnO, MgO, CaO, Al2O3 have been extensively used in biological applications. Zinc Oxide is a Wurtzite-type semiconductor and piezo-electric material exhibiting excellent electrical, optical and chemical properties with a band energy gap of 3.1-3.4 eV. Nanoforms of Zinc Oxide (ZnO) are increasingly recognised for their utility in biological application. The significant physical parameters such as surface area, particle size, surface charge and Zeta potential of Zinc Oxide (ZnO) nanoparticles makes it suitable for the uptake, persistance, biological, and chemical activities inside the living cells. The present study shows the effect of intrinsic defects of ZnO nanocrystals synthesized by high energy ball milling (HEBM) technique in their antibacterial activities. Bulk Zinc oxide purchased from market were ball milled for 7 h, 10 h, and 15 h respectively to produce nanosized Zinc Oxide. The structural and optical modification of such synthesized particles were determined by X-ray diffraction (XRD), Scanning Electron Microscopy and Electron Paramagnetic Resonance (EPR). The antibacterial property of synthesized Zinc Oxide nanoparticles was tested using well diffusion, minimum inhibitory Concentration, minimum bacteriocidal concentration, reactive oxygen species (ROS) estimation and membrane potential determination methods. In this study we observed that antibacterial activity of ZnO nanoparticles is because of the intrinsic defects that exist as a function of difference in size and milling time.

Keywords: high energy ball milling, ZnO nanoparticles, EPR, Antibacterial properties

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Authors: A. I. Dovgjallo, A. B. Tsapkova, A. A. Shimanov

Abstract:

The paper is devoted to one of engine types with external heating – a thermoacoustic engine. In thermoacoustic engine heat energy is converted to an acoustic energy. Further, acoustic energy of oscillating gas flow must be converted to mechanical energy and this energy in turn must be converted to electric energy. The most widely used way of transforming acoustic energy to electric one is application of linear generator or usual generator with crank mechanism. In both cases, the piston is used. Main disadvantages of piston use are friction losses, lubrication problems and working fluid pollution which cause decrease of engine power and ecological efficiency. Using of a bidirectional impulse turbine as an energy converter is suggested. The distinctive feature of this kind of turbine is that the shock wave of oscillating gas flow passing through the turbine is reflected and passes through the turbine again in the opposite direction. The direction of turbine rotation does not change in the process. Different types of bidirectional impulse turbines for thermoacoustic engines are analyzed. The Wells turbine is the simplest and least efficient of them. A radial impulse turbine has more complicated design and is more efficient than the Wells turbine. The most appropriate type of impulse turbine was chosen. This type is an axial impulse turbine, which has a simpler design than that of a radial turbine and similar efficiency. The peculiarities of the method of an impulse turbine calculating are discussed. They include changes in gas pressure and velocity as functions of time during the generation of gas oscillating flow shock waves in a thermoacoustic system. In thermoacoustic system pressure constantly changes by a certain law due to acoustic waves generation. Peak values of pressure are amplitude which determines acoustic power. Gas, flowing in thermoacoustic system, periodically changes its direction and its mean velocity is equal to zero but its peak values can be used for bi-directional turbine rotation. In contrast with feed turbine, described turbine operates on un-steady oscillating flows with direction changes which significantly influence the algorithm of its calculation. Calculated power output is 150 W with frequency 12000 r/min and pressure amplitude 1,7 kPa. Then, 3-d modeling and numerical research of impulse turbine was carried out. As a result of numerical modeling, main parameters of the working fluid in turbine were received. On the base of theoretical and numerical data model of impulse turbine was made on 3D printer. Experimental unit was designed for numerical modeling results verification. Acoustic speaker was used as acoustic wave generator. Analysis if the acquired data shows that use of the bi-directional impulse turbine is advisable. By its characteristics as a converter, it is comparable with linear electric generators. But its lifetime cycle will be higher and engine itself will be smaller due to turbine rotation motion.

Keywords: acoustic power, bi-directional pulse turbine, linear alternator, thermoacoustic generator

Procedia PDF Downloads 361

Authors: Rachid Essamoud, Abdelkrim Afenzar, Ahmed Belqadi

Abstract:

During the Early Mesozoic, the northwestern part of the African continent was affected by initial fracturing associated with the early stages of the opening of the Central Atlantic (Atlantic Rift). During this rifting phase, the Moroccan Meseta experienced an extensive tectonic regime. This extension favored the formation of a set of rift-type basins, including the Mohammedia-Benslimane-ElGara-Berrechid basin. Thus, it is essential to know the nature of the deposits in this basin and their evolution over time as well as their relationship with the basaltic effusion of the Central Atlantic Magmatic Province (CAMP). These deposits are subdivided into two large series: The Lower clay-salt series attributed to the Triassic and the Upper clay-salt series attributed to the Liassic. The two series are separated by the Upper Triassic-Lower Liassic basaltic complex. The detailed sedimentological analysis made it possible to characterize four mega-sequences, fifteen types of facies and eight architectural elements and facies associations in the Triassic series. A progressive decrease observed in paleo-slope over time led to the evolution of the paleoenvironment from a proximal system of alluvial fans to a braided fluvial style, then to an anastomosed system. These environments eventually evolved into an alluvial plain associated with a coastal plain where playa lakes, mudflats and lagoons had developed. The pure and massive halitic facies at the top of the series probably indicate an evolution of the depositional environment towards a shallow subtidal environment. The presence of these evaporites indicates a climate that favored their precipitation, in this case, a fairly hot and humid climate. The sedimentological analysis of the supra-basaltic part shows that during the Lower Liassic, the paleopente after basaltic effusion remained weak with distal environments. The faciological analysis revealed the presence of four major sandstone, silty, clayey and evaporitic lithofacies organized in two mega-sequences: the sedimentation of the first rock-salt mega-sequence took place in a brine depression system free, followed by saline mudflats under continental influences. The upper clay mega-sequence displays facies documenting sea level fluctuations from the final transgression of the Tethys or the opening Atlantic. Saliferous sedimentation is therefore favored from the Upper Triassic, but experienced a sudden rupture by the emission of basaltic flows which are interstratified in the azoic salt clays of very shallow seas. This basaltic emission which belongs to the CAMP would come from a fissural volcanism probably carried out through transfer faults located in the NW and SE of the basin. Their emplacement is probably subaquatic to subaerial. From a chronological and paleogeographic point of view, this main volcanism, dated between the Upper Triassic and the Lower Liassic (180-200 MA), is linked to the fragmentation of Pangea and managed by a progressive expansion triggered in the West in close relation with the initial phases of Central Atlantic rifting and seems to coincide with the major mass extinction at the Triassic-Jurassic boundary.

Keywords: Basalt, CAMP, Liassic, sedimentology, Triassic, Morocco

Procedia PDF Downloads 57

Authors: Sh. Sousani, Z. Shadrokh, M. Hofbauerová, J. Kollár, M. Jergel, P. Nádaždy, M. Omastová, E. Majková

Abstract:

Perovskite quantum dots (PQDs) have the potential to increase the performance of the perovskite solar cell (PSCs). The integration of PQDs into PSCs can extend the absorption range and enhance photon harvesting and device efficiency. In addition, PQDs can stabilize the device structure by passivating surface defects and traps in the perovskite layer and enhance its stability. The integration of PQDs into PSCs is strongly affected by the type of ligands on the surface of PQDs. The ligands affect the charge transport properties of PQDs, as well as the formation of well-defined interfaces and stability of PSCs. In this work, the CsPbBr₃ QDs were synthesized by the conventional hot-injection method using cesium oleate, PbBr₂ and two different ligands, namely oleic acid (OA) oleylamine (OAm) and didodecyldimethylammonium bromide (DDAB). The STEM confirmed regular shape and relatively monodisperse cubic structure with an average size of about 10-14 nm of the prepared CsPbBr₃ QDs. Further, the photoluminescent (PL) properties of the PQDs/perovskite bilayer with the ligand OA, OAm and DDAB were studied. For this purpose, ITO/PQDs as well as ITO/PQDs/MAPI perovskite structures were prepared by spin coating and the effect of the ligand and oxygen plasma treatment was analyzed. The plasma treatment of the PQDs layer could be beneficial for the deposition of the MAPI perovskite layer and the formation of a well-defined PQDs/MAPI interface. The absorption edge in UV-Vis absorption spectra for OA, OAm CsPbBr₃ QDs is placed around 513 nm (the band gap 2.38 eV); for DDAB CsPbBr₃ QDs, it is located at 490 nm (the band gap 2.33 eV). The photoluminescence (PL) spectra of CsPbBr₃ QDs show two peaks located around 514 nm (503 nm) and 718 nm (708 nm) for OA, OAm (DDAB). The peak around 500 nm corresponds to the PL of PQDs, and the peak close to 710 nm belongs to the surface states of PQDs for both types of ligands. These surface states are strongly affected by the O₃ plasma treatment. For PQDs with DDAB ligand, the O₃ exposure (5, 10, 15 s) results in the blue shift of the PQDs peak and a non-monotonous change of the amplitude of the surface states' peak. For OA, OAm ligand, the O₃ exposition did not cause any shift of the PQDs peak, and the intensity of the PL peak related to the surface states is lower by one order of magnitude in comparison with DDAB, being affected by O₃ plasma treatment. The PL results indicate the possibility of tuning the position of the PL maximum by the ligand of the PQDs. Similar behavior of the PQDs layer was observed for the ITO/QDs/MAPI samples, where an additional strong PL peak at 770 nm coming from the perovskite layer was observed; for the sample with PQDs with DDAB ligands, a small blue shift of the perovskite PL maximum was observed independently of the plasma treatment. These results suggest the possibility of affecting the PL maximum position and the surface states of the PQDs by the combination of a suitable ligand and the O₃ plasma treatment.

Keywords: perovskite quantum dots, photoluminescence, O₃ plasma., Perovskite Solar Cells

Procedia PDF Downloads 51

Authors: Sh. Sousani, Z. Shadrokh, M. Hofbauerová, J. Kollár, M. Jergel, P. Nádaždy, M. Omastová, E. Majková

Abstract:

Perovskite quantum dots (PQDs) have the potential to increase the performance of the perovskite solar cells (PSCs). The integration of PQDs into PSCs can extend the absorption range and enhance photon harvesting and device efficiency. In addition, PQDs can stabilize the device structure by passivating surface defects and traps in the perovskite layer and enhance its stability. The integration of PQDs into PSCs is strongly affected by the type of ligands on the surface of PQDs. The ligands affect the charge transport properties of PQDs, as well as the formation of well-defined interfaces and stability of PSCs. In this work, the CsPbBr₃ QDs were synthesized by the conventional hot-injection method using cesium oleate, PbBr₂, and two different ligands, namely oleic acid (OA)@oleylamine (OAm) and didodecyldimethylammonium bromide (DDAB). The STEM confirmed regular shape and relatively monodisperse cubic structure with an average size of about 10-14 nm of the prepared CsPbBr₃ QDs. Further, the photoluminescent (PL) properties of the PQDs/perovskite bilayer with the ligand OA@OAm and DDAB were studied. For this purpose, ITO/PQDs, as well as ITO/PQDs/MAPI perovskite structures, were prepared by spin coating, and the effect of the ligand and oxygen plasma treatment was analysed. The plasma treatment of the PQDs layer could be beneficial for the deposition of the MAPI perovskite layer and the formation of a well-defined PQDs/MAPI interface. The absorption edge in UV-Vis absorption spectra for OA@OAm CsPbBr₃ QDs is placed around 513 nm (the band gap 2.38 eV); for DDAB CsPbBr₃ QDs, it is located at 490 nm (the band gap 2.33 eV). The photoluminescence (PL) spectra of CsPbBr₃ QDs show two peaks located around 514 nm (503 nm) and 718 nm (708 nm) for OA@OAm (DDAB). The peak around 500 nm corresponds to the PL of PQDs, and the peak close to 710 nm belongs to the surface states of PQDs for both types of ligands. These surface states are strongly affected by the O₃ plasma treatment. For PQDs with DDAB ligand, the O₃ exposure (5, 10, 15 s) results in the blue shift of the PQDs peak and a non-monotonous change of the amplitude of the surface states' peak. For OA@OAm ligand, the O₃ exposition did not cause any shift of the PQDs peak, and the intensity of the PL peak related to the surface states is lower by one order of magnitude in comparison with DDAB, being affected by O₃ plasma treatment. The PL results indicate the possibility of tuning the position of the PL maximum by the ligand of the PQDs. Similar behaviour of the PQDs layer was observed for the ITO/QDs/MAPI samples, where an additional strong PL peak at 770 nm coming from the perovskite layer was observed; for the sample with PQDs with DDAB ligands, a small blue shift of the perovskite PL maximum was observed independently of the plasma treatment. These results suggest the possibility of affecting the PL maximum position and the surface states of the PQDs by the combination of a suitable ligand and the O₃ plasma treatment.

Keywords: perovskite quantum dots, photoluminescence, O₃ plasma., perovskite solar cells

Procedia PDF Downloads 54

Authors: George Kyriakopoulos, Photini Pazartzis, Anthi Koskina, Crystalie Bourcha

Abstract:

The need for securing safe access to and return from outer space, as well as ensuring the viability of outer space operations, maintains vivid the debate over the promotion of organization of space traffic through a Space Traffic Management System (STM). The proliferation of outer space activities in recent years as well as the dynamic emergence of the private sector has gradually resulted in a diverse universe of actors operating in outer space. The said developments created an increased adverse impact on outer space sustainability as the case of the growing number of space debris clearly demonstrates. The above landscape sustains considerable threats to outer space environment and its operators that need to be addressed by a combination of scientific-technological measures and regulatory interventions. In this context, recourse to recent technological advancements and, in particular, to Artificial Intelligence (AI) and machine learning systems, could achieve exponential results in promoting space traffic management with respect to collision avoidance as well as launch and re-entry procedures/phases. New technologies can support the prospects of a successful space traffic management system at an international scale by enabling, inter alia, timely, accurate and analytical processing of large data sets and rapid decision-making, more precise space debris identification and tracking and overall minimization of collision risks and reduction of operational costs. What is more, a significant part of space activities (i.e. launch and/or re-entry phase) takes place in airspace rather than in outer space, hence the overall discussion also involves the highly developed, both technically and legally, international (and national) Air Traffic Management System (ATM). Nonetheless, from a regulatory perspective, the use of AI for the purposes of space traffic management puts forward implications that merit particular attention. Key issues in this regard include the delimitation of AI-based activities as space activities, the designation of the applicable legal regime (international space or air law, national law), the assessment of the nature and extent of international legal obligations regarding space traffic coordination, as well as the appropriate liability regime applicable to AI-based technologies when operating for space traffic coordination, taking into particular consideration the dense regulatory developments at EU level. In addition, the prospects of institutionalizing international cooperation and promoting an international governance system, together with the challenges of establishment of a comprehensive international STM regime are revisited in the light of intervention of AI technologies. This paper aims at examining regulatory implications advanced by the use of AI technology in the context of space traffic management operations and its key correlating concepts (SSA, space debris mitigation) drawing in particular on international and regional considerations in the field of STM (e.g. UNCOPUOS, International Academy of Astronautics, European Space Agency, among other actors), the promising advancements of the EU approach to AI regulation and, last but not least, national approaches regarding the use of AI in the context of space traffic management, in toto. Acknowledgment: The present work was co-funded by the European Union and Greek national funds through the Operational Program "Human Resources Development, Education and Lifelong Learning " (NSRF 2014-2020), under the call "Supporting Researchers with an Emphasis on Young Researchers – Cycle B" (MIS: 5048145).

Keywords: artificial intelligence, space traffic management, space situational awareness, space debris

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Authors: Kasra Afsahi, Maryam Soheilifar, S. Hossein Hosseini, Omid Seyed Esmaeili, Rouzbeh Kezemi, Noushin Mehrbod, Nazanin Vahed, Tahereh Hajiahmad, Noureddin Nakhostin Ansari

Abstract:

Background: Stroke is a disabling neurological disease. Rehabilitative therapies are important treatment methods. This clinical trial was done to compare the effects of VR beside conventional rehabilitation versus conventional rehabilitation alone on spasticity and motor function in stroke patients. Materials and Methods: In this open-label randomized controlled clinical trial, 40 consecutive patients with stable first-ever ischemic stroke in the past three to 12 months that were referred to a rehabilitation clinic in Tehran, Iran, in 2020 were enrolled. After signing the informed written consent form, subjects were randomly assigned by block randomization of five in each block as cases with 1:1 into two groups of 20 cases; conventional plus VR therapy group: 45-minute conventional therapy session plus 15-minute VR therapy, and conventional group: 60-minute conventional therapy session. VR rehabilitation is designed and developed with different stages. Outcomes were modified Ashworth scale, recovery stage score for motor function, range of motion (ROM) of shoulder abduction/wrist extension, and patients’ satisfaction rate. Data were compared after study termination. Results: The satisfaction rate among the patients was significantly better in the combination group (P=0.003). Only wrist extension was varied between groups and was better in the combination group. The variables generally had a statistically significant difference (P < 0.05). Conclusion: Virtual reality plus conventional rehabilitation therapy is superior versus conventional rehabilitation alone on the wrist and elbow spasticity and motor function in patients with stroke.

Keywords: stroke, virtual therapy, rehabilitation, treatment

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Authors: A. Drapeaux, S. Aviles, E. Garfoot

Abstract:

Stem cell injections are a promising alternative treatment for hip osteoarthritis. Current literature has focused on short-term outcomes for both knee and hip osteoarthritis; however, there is a significant gap for longitudinal benefits for hip OA and limited firm conclusions due to small sample sizes. The purpose of this prospective study was to determine longitudinal changes in pain, function, and radiographs following bone marrow concentrate injection (BMAC) into the osteoarthritic hip joint. Methods: A prospective, cross-sectional study was conducted over the course of 12 months at an orthopedic practice. The study recruited 15 osteoarthritic pre-surgical hips with mild to moderate osteoarthritic severity who were scheduled to undergo hip arthroscopy. Data was collected at both pre-operative and post-operative time frames. Data collected included: hip radiographs, i-HOT-33 questionnaire data, BMAC autologous volume, and demographics. Questionnaire data was captured using Qualtrics XM software, and participants were sent an anonymous link at the following time frames: pre-operative, 2 weeks, 6 weeks, 12 weeks, 6 months, 12 months, and 24 months. Radiographic changes and BMAC volume were collected and reviewed by an orthopedic surgeon and sent to the primary investigator. Data was exported and analyzed in IBM-SPSS. Results: A total of 15 hips from 15 participants (mean age: 49, gender: 50% males, 50% females, BMI: 29.7) were used in the final analysis. Summative i-HOT 33 mean scores significantly changed between pre-operative status and 2-6 weeks post-operative status (p <.001) and pre-operative status and 3-6 months post-operative status (p <.001). There were no significant changes between other post-operative phases or between pre-operative status and 12 months post-operative. Significant improvements were found between summative i-HOT 33 mean (p<.001), daily pain (p<.001), daily sitting (p=.02), daily distance walked (p =.003), and daily limp (p=0.03) and post-operative status (2-6 weeks). No significant differences between demographic variables (gender, age, tobacco use, or diabetes) and i-HOT 33 summative mean scores. Discussion/Implications: The purpose of this study was to determine longitudinal changes in pain and function following a hip joint bone marrow concentrate injection. Results indicate that participants experience a significant improvement in pain and function between pre-operative and 2-6 weeks and 3-6 months post-injection. Participants also self-reported a significant change in average daily pain with sitting and walking between pre-operation and 2-6 weeks post-operative. This study includes a larger sample size of hip osteoarthritis cases; however, future research is warranted to include random controlled trials with a larger sample size.

Keywords: adult stem cell, orthopedics, osteoarthritis (hip), patient outcome assessment

Procedia PDF Downloads 46