Search results for: magnetic circuit material

Authors: Willem J. A. Louw

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The wave of new advanced computing technology that has been developed during the recent past has significantly changed the way we communicate, collaborate and collect information. It has created a new technology environment and paradigm in which our children and students grow-up and this impacts on their learning. Research confirmed that Generation Y students have a preference for learning in the new technology environment. The challenge or question is: How do we adjust our teaching and learning to make the most of these changes. The complexity of effective and efficient teaching and learning must not be underestimated and changes must be preceded by proper objective research to prevent any haphazard developments that could do more harm than benefit. A blended learning approach has been used in the Forestry department for a few numbers of years including the use of electronic-peer assisted learning (e-pal) in a fixed-computer set-up within a learning management system environment. It was decided to extend the investigation and do some exploratory research by using a range of different Tablet devices. For this purpose, learning activities or assignments were designed to cover aspects of communication, collaboration and collection of information. The Moodle learning management system was used to present normal module information, to communicate with students and for feedback and data collection. Student feedback was collected by using an online questionnaire and informal discussions. The research project was implemented in 2013, 2014 and 2015 amongst first and third-year students doing a forestry three-year technical tertiary qualification in commercial plantation management. In general, more than 80% of the students alluded to that the device was very useful in their learning environment while the rest indicated that the devices were not very useful. More than ninety percent of the students acknowledged that they would like to continue using the devices for all of their modules whilst the rest alluded to functioning efficiently without the devices. Results indicated that information collection (access to resources) was rated the highest advantageous factor followed by communication and collaboration. The main general advantages of using Tablets were listed by the students as being mobility (portability), 24/7 access to learning material and information of any kind on a user friendly device in a Wi-Fi environment, fast computing process speeds, saving time, effort and airtime through skyping and e-mail, and use of various applications. Ownership of the device is a critical factor while the risk was identified as a major potential constraint. Significant differences were reported between the different types and quality of Tablets. The preferred types are those with a bigger screen and the ones with overall better functionality and quality features. Tablets significantly increase the collaboration, communication and information collection needs of the students. It does, however, not replace the need of a computer/laptop because of limited storage and computation capacity, small screen size and inefficient typing.

Keywords: tablets, teaching, blended learning, tablet quality

Procedia PDF Downloads 248

Authors: Gilda Santos, Rita Marques, Francisca Marques, João Ribeiro, André Fonseca, João M. Miranda, João B. L. M. Campos, Soraia F. Neves

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Every year, an unacceptable number of firefighters are seriously burned during firefighting operations, with some of them eventually losing their life. Although thermal protective clothing research and development has been searching solutions to minimize firefighters heat load and skin burns, currently commercially available solutions focus in solving isolated problems, for example, radiant heat or water-vapor resistance. Therefore, episodes of severe burns and heat strokes are still frequent. Taking this into account, a consortium composed by Portuguese entities has joined synergies to develop an innovative protective clothing system by following a procedure based on the application of numerical models to optimize the design and using a combinationof protective clothing components disposed in different layers. Recently, it has been shown that Phase Change Materials (PCMs) can contribute to the reduction of potential heat hazards in fire extinguish operations, and consequently, their incorporation into firefighting protective clothing has advantages. The greatest challenge is to integrate these materials without compromising garments ergonomics and, at the same time, accomplishing the International Standard of protective clothing for firefighters – laboratory test methods and performance requirements for wildland firefighting clothing. The incorporation of PCMs into the firefighter's protective jacket will result in the absorption of heat from the fire and consequently increase the time that the firefighter can be exposed to it. According to the project studies and developments, to favor a higher use of the PCM storage capacityand to take advantage of its high thermal inertia more efficiently, the PCM layer should be closer to the external heat source. Therefore, in this stage, to integrate PCMs in firefighting clothing, a mock-up of a vest specially designed to protect the torso (back, chest and abdomen) and to be worn over a fire-resistant jacketwas envisaged. Different configurations of PCMs, as well as multilayer approaches, were studied using suitable joining technologies such as bonding, ultrasound, and radiofrequency. Concerning firefighter’s protective clothing, it is important to balance heat protection and flame resistance with comfort parameters, namely, thermaland water-vapor resistances. The impact of the most promising solutions regarding thermal comfort was evaluated to refine the performance of the global solutions. Results obtained with experimental bench scale model and numerical simulation regarding the integration of PCMs in a vest designed as protective clothing for firefighters will be presented.

Keywords: firefighters, multilayer system, phase change material, thermal protective clothing

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Authors: Mursleen Yasin, Sunil Panchal, Michelle Mak, Zhonghua Chen

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“The use of agricultural and horticultural waste to obtain beneficial products. Thus reduce its environmental impact and help the general population.” Every year 20 billion dollars of food is wasted in the world. All the energy, resources, nutrients and metabolites are lost to the landfills as well. On farm production losses are a main issue in agriculture. Almost 25% vegetables never leave the farm because they are not considered perfect for supermarkets and treated as waste material along with the rest of the plant parts. For capsicums, this waste is 56% of the total crop. Capsicum genus is enriched with a group of compounds called capsaicinoids which are a source of spiciness of these fruits. Capsaicin and dihydrocapsaicin are the major members comprising almost 90% of this group. The major production and accumulation site is the non-edible part of fruit i.e., placenta. Other parts of the plant, like stem, leaves, pericarp and seeds, also contain these pungent compounds. Capsaicinoids are enriched with properties like analgesic, antioxidants, anti-inflammatory, antibacterial, anti-virulence anti-carcinogenic, chemo preventive, chemotherapeutic, antidiabetic etc. They are also effective in treating problems related to gastrointestinal tract, lowering cholesterol and triglycerides in obesity. The aim of the study is to develop a standardised technique for capsaicinoids extraction and to identify better nutrient treatment for fruit and capsaicinoids yield. For research 3 capsicum and 2 chilli varieties were grown in a high-tech glass house facility in Sydney, Australia. Plants were treated with three levels of nutrient treatments i.e., EC 1.8, EC 2.8 and EC 3.8 in order to check its effect on fruit yield and capsaicinoids concentration. Solvent extraction procedure is used with 75% ethanol to extract these secondary metabolites. Physiological, post-harvest and waste biomass measurement and metabolomic analysis are also performed. The results showed that EC 2.8 gave the better fruit yield of capsicums, and those fruits have the higher capsaicinoids concentration. For chillies, higher EC levels had better results than lower treatment. The UHPLC analysis is done to quantify the compounds, and a decrease in capsaicin concentration is observed with the crop maturation. The outcome of this project is a sustainable technique for extraction of capsaicinoids which can easily be adopted by farmers. In this way, farmers can help in value adding of waste by extracting and selling capsaicinoids to nutraceutical and pharmaceutical industries and also earn some secondary income from the 56% waste of capsicum crop.

Keywords: capsaicinoids, plant waste, capsicum, solvent extraction, waste biomass

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Authors: Amit Sarkar, Jayanta K. Mahato, Tushar Bhattacharya, Amrita Kundu, P. C. Chakraborti

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With increasing the demand for safety and fuel efficiency of automobiles, automotive manufacturers are looking for light weight, high strength steel with excellent formability and corrosion resistance. Dual-phase steel is finding applications in automotive sectors, because of its high strength, good formability, and high corrosion resistance. During service automotive components suffer from environmental attack and thereby gradual degradation of the components occurs reducing the service life of the components. The objective of the present investigation is to assess the effect of deformation on corrosion behaviour of DP590 grade dual phase steel which is used in automotive industries. The material was received from TATA Steel Jamshedpur, India in the form of 1 mm thick sheet. Tensile properties of the steel at strain rate of 10-3 sec-1: 0.2 % Yield Stress is 382 MPa, Ultimate Tensile Strength is 629 MPa, Uniform Strain is 16.30% and Ductility is 29%. Rectangular strips of 100x10x1 mm were machined keeping the long axis of the strips parallel to rolling direction of the sheet. These strips were longitudinally deformed at a strain rate at 10-3 sec-1 to a different percentage of strain, e.g. 2.5, 5, 7.5,10 and 12.5%, and then slowly unloaded. Small specimens were extracted from the mid region of the unclamped portion of these deformed strips. These small specimens were metallographic polished, and corrosion behaviour has been studied by potentiodynamic polarization, electrochemical impedance spectra, and cyclic polarization and potentiostatic tests. Present results show that among three different environments, the 3.5 pct NaCl solution is most aggressive in case of DP 590 dual-phase steel. It is observed that with the increase in the amount of deformation, corrosion rate increases. With deformation, the stored energy increases and leads to enhanced corrosion rate. Cyclic polarization results revealed highly deformed specimen are more prone to pitting corrosion as compared to the condition when amount of deformation is less. It is also observed that stability of the passive layer decreases with the amount of deformation. With the increase of deformation, current density increases in a passive zone and passive zone is also decreased. From Electrochemical impedance spectroscopy study it is found that with increasing amount of deformation polarization resistance (Rp) decreases. EBSD results showed that average geometrically necessary dislocation density increases with increasing strain which in term increased galvanic corrosion as dislocation areas act as the less noble metal.

Keywords: dual phase 590 steel, prestrain, potentiodynamic polarization, cyclic polarization, electrochemical impedance spectra

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Authors: Xianghe Dai, Dennis Lam, Therese Sheehan, Naveed Rehman, Jie Yang

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Concrete is one of the most used construction materials that may be made onsite as fresh concrete and then placed in formwork to produce the desired shapes of structures. It has been recognized that the raw materials and mix proportion of concrete dominate the mechanical characteristics of hardened concrete, and the curing method and environment applied to the concrete in early stages of hardening will significantly influence the concrete properties, such as compressive strength, durability, permeability etc. In construction practice, there are various curing methods to maintain the presence of mixing water throughout the early stages of concrete hardening. They are also beneficial to concrete in hot weather conditions as they provide cooling and prevent the evaporation of water. Such methods include ponding or immersion, spraying or fogging, saturated wet covering etc. Also there are various curing methods that may be implemented to decrease the level of water lost which belongs to the concrete surface, such as putting a layer of impervious paper, plastic sheeting or membrane on the concrete to cover it. In the concrete material laboratory, accelerated strength gain methods supply the concrete with heat and additional moisture by applying live steam, coils that are subject to heating or pads that have been warmed electrically. Currently when determining the mechanical parameters of a concrete, the concrete is usually sampled from fresh concrete on site and then cured and tested in laboratories where standardized curing procedures are adopted. However, in engineering practice, curing procedures in the construction sites after the placing of concrete might be very different from the laboratory criteria, and this includes some standard curing procedures adopted in the laboratory that can’t be applied on site. Sometimes the contractor compromises the curing methods in order to reduce construction costs etc. Obviously the difference between curing procedures adopted in the laboratory and those used on construction sites might over- or under-estimate the real concrete quality. This paper presents the effect of three typical curing methods (air curing, water immersion curing, plastic film curing) and of maintaining concrete in steel moulds on the compressive strength development of normal concrete. In this study, Portland cement with 30% fly ash was used and different curing periods, 7 days, 28 days and 60 days were applied. It was found that the highest compressive strength was observed from concrete samples to which 7-day water immersion curing was applied and from samples maintained in steel moulds up to the testing date. The research results implied that concrete used as infill in steel tubular members might develop a higher strength than predicted by design assumptions based on air curing methods. Wrapping concrete with plastic film as a curing method might delay the concrete strength development in the early stages. Water immersion curing for 7 days might significantly increase the concrete compressive strength.

Keywords: compressive strength, air curing, water immersion curing, plastic film curing, maintaining in steel mould, comparison

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Authors: Suteera Pradubwong, Pattama Surit, Sumalee Pongpagatip, Tharinee Pethchara, Bowornsilp Chowchuen

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Background: Cleft lip and palate (CLP) is a congenital anomaly of the lip and palate that is caused by several factors. It was found in approximately one per 500 to 550 live births depending on nationality and socioeconomic status. The Tawanchai Center and out-patients surgical room of Srinagarind Hospital are responsible for providing care to patients with CLP (starting from birth to adolescent) and their caregivers. From the observations and interviews with nurses working in these units, they reported that both patients and their caregivers confronted many problems which affected their physical and mental health. Based on the Soukup’s model (2000), the researchers used evidence triggers from clinical practice (practice triggers) and related literature (knowledge triggers) to investigate the problems. Objective: The purpose of this study was to investigate the problems of care for patients with CLP in the Tawanchai Center and out-patient surgical room of Srinagarind Hospital. Material and Method: The descriptive method was used in this study. For practice triggers, the researchers obtained the data from medical records of ten patients with CLP and from interviewing two patients with CLP, eight caregivers, two nurses, and two assistant workers. Instruments for the interview consisted of a demographic data form and a semi-structured questionnaire. For knowledge triggers, the researchers used a literature search. The data from both practice and knowledge triggers were collected between February and May 2016. The quantitative data were analyzed through frequency and percentage distributions, and the qualitative data were analyzed through a content analysis. Results: The problems of care gained from practice and knowledge triggers were consistent and were identified as holistic issues, including 1) insufficient feeding, 2) risks of respiratory tract infections and physical disorders, 3) psychological problems, such as anxiety, stress, and distress, 4) socioeconomic problems, such as stigmatization, isolation, and loss of income, 5)spiritual problems, such as low self-esteem and low quality of life, 6) school absence and learning limitation, 7) lack of knowledge about CLP and its treatments, 8) misunderstanding towards roles among the multidisciplinary team, 9) no available services, and 10) shortage of healthcare professionals, especially speech-language pathologists (SLPs). Conclusion: From evidence-triggers, the problems of care affect the patients and their caregivers holistically. Integrated long-term care by the multidisciplinary team is needed for children with CLP starting from birth to adolescent. Nurses should provide effective care to these patients and their caregivers by using a holistic approach and working collaboratively with other healthcare providers in the multidisciplinary team.

Keywords: evidence-triggers, cleft lip, cleft palate, problems of care

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Authors: Maryam Hasanali, Syed Mohammad Mojtabaei, Iman Hajirasouliha, G. Charles Clifton, James B. P. Lim

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Cold-formed steel (CFS) elements are increasingly being used as main load-bearing components in the modern construction industry, including low- to mid-rise buildings. In typical multi-storey buildings, CFS structural members act as beam-column elements since they are exposed to combined axial compression and bending actions, both in moment-resisting frames and stud wall systems. Current design specifications, including the American Iron and Steel Institute (AISI S100) and the Australian/New Zealand Standard (AS/NZS 4600), neglect the beneficial effects of warping-restrained boundary conditions in the design of beam-column elements. Furthermore, while a non-linear relationship governs the interaction of axial compression and bending, the combined effect of these actions is taken into account through a simplified linear expression combining pure axial and flexural strengths. This paper aims to evaluate the reliability of the well-known Direct Strength Method (DSM) as well as design proposals found in the literature to provide a better understanding of the efficiency of the code-prescribed linear interaction equation in the strength predictions of CFS beam columns and the effects of warping-restrained boundary conditions on their behavior. To this end, the experimentally validated finite element (FE) models of CFS elements under compression and bending were developed in ABAQUS software, which accounts for both non-linear material properties and geometric imperfections. The validated models were then used for a comprehensive parametric study containing 270 FE models, covering a wide range of key design parameters, such as length (i.e., 0.5, 1.5, and 3 m), thickness (i.e., 1, 2, and 4 mm) and cross-sectional dimensions under ten different load eccentricity levels. The results of this parametric study demonstrated that using the DSM led to the most conservative strength predictions for beam-column members by up to 55%, depending on the element’s length and thickness. This can be sourced by the errors associated with (i) the absence of warping-restrained boundary condition effects, (ii) equations for the calculations of buckling loads, and (iii) the linear interaction equation. While the influence of warping restraint is generally less than 6%, the code suggested interaction equation led to an average error of 4% to 22%, based on the element lengths. This paper highlights the need to provide more reliable design solutions for CFS beam-column elements for practical design purposes.

Keywords: beam-columns, cold-formed steel, finite element model, interaction equation, warping-restrained boundary conditions

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Authors: Ahlam Ali, Katrina Lappin, Jaine Blayney, Ken Mills

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Leukaemia is the most frequently (30%) occurring type of paediatric cancer. Of these, approximately 80% are acute lymphoblastic leukaemia (ALL) with acute myeloid leukaemia (AML) cases making up the remaining 20% alongside other leukaemias. Unfortunately, children with AML do not have promising prognosis with only 60% surviving 5 years or longer. It has been highlighted recently the need for age-specific therapies for AML patients, with paediatric AML cases having a different mutational landscape compared with AML diagnosed in adult patients. Drug Repurposing is a recognized strategy in drug discovery and development where an already approved drug is used for diseases other than originally indicated. We aim to identify novel combination therapies with the promise of providing alternative more effective and less toxic induction therapy options. Our in-silico analysis highlighted ‘cell death and survival’ as an aberrant, potentially targetable pathway in paediatric AML patients. On this basis, 83 apoptotic inducing compounds were screened. A preliminary single agent screen was also performed to eliminate potentially toxic chemicals, then drugs were constructed into a pooled library with 10 drugs per well over 160 wells, with 45 possible pairs and 120 triples in each well. Seven cell lines were used during this study to represent the clonality of AML in paediatric patients (Kasumi-1, CMK, CMS, MV11-14, PL21, THP1, MOLM-13). Cytotoxicity was assessed up to 72 hours using CellTox™ Green reagent. Fluorescence readings were normalized to a DMSO control. Z-Score was assigned to each well based on the mean and standard deviation of all the data. Combinations with a Z-Score <2 were eliminated and the remaining wells were taken forward for further analysis. A well was considered ‘successful’ if each drug individually demonstrated a Z-Score <2, while the combination exhibited a Z-Score >2. Each of the ten compounds in one well (155) had minimal or no effect as single agents on cell viability however, a combination of two or more of the compounds resulted in a substantial increase in cell death, therefore the ten compounds were de-convoluted to identify a possible synergistic pair/triple combinations. The screen identified two possible ‘novel’ drug pairing, with BCL2 inhibitor ABT-737, combined with either a CDK inhibitor Purvalanol A, or AKT/ PI3K inhibitor LY294002. (ABT-737- 100 nM+ Purvalanol A- 1 µM) (ABT-737- 100 nM+ LY294002- 2 µM). Three possible triple combinations were identified (LY2409881+Akti-1/2+Purvalanol A, SU9516+Akti-1/2+Purvalanol A, and ABT-737+LY2409881+Purvalanol A), which will be taken forward for examining their efficacy at varying concentrations and dosing schedules, across multiple paediatric AML cell lines for optimisation of maximum synergy. We believe that our combination screening approach has potential for future use with a larger cohort of drugs including FDA approved compounds and patient material.

Keywords: AML, drug repurposing, ABT-737, apoptosis

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Authors: Helene Jacobson Pettersson, Linda Lill

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Research that combines educational science, social work and migration studies shows that ethnic relations tend to be represented from various angles and with different content. As studied here, it is found in steering documents, literature, and teaching that the construction of ethnic relations related to social work varies in education over time. The study has its actuality in changed preconditions to social work education caused by the demographic development and the on-going globalization in the Swedish society. In this presentation we will explore strategies and experiences of teaching ethnic relations at social work educations in Sweden. The purpose is to investigate the strategies that are used and what content is given to ethnic relations in the social work education. University teachers are interviewed concerning their interpretation of steering documents related to the content and how they transform this in their teaching. Even though there has been a tradition to include aspects as intercultural relations and ethnicity, the norms of the welfare state has continued to be the basis for how to conceptualize people’s way of living and social problems. Additionally, the contemporary migration situation with a large number of refugees coming to Sweden peaking in 2015, dramatically changes the conditions for social work as a practice field. Increasing economic and social tensions in Sweden, becomes a challenge for the universities to support the students to achieve theoretical and critical knowledge and skills needed to work for social change, human rights and equality in the ethnic diverse Swedish society. The study raises questions about how teachers interpret the goals of the social work programs in terms of ethnic relations. How do they transform this into teaching? How are ethnic relations in social work described and problematized in lectures, cases and examinations? The empirical material is based on interviews with teachers involved in the social work education at four Swedish universities. The interviewees were key persons in the sense that they could influence the course content, and they were drawn from different semesters of the program. In depth interviews are made on the themes; personal entrance, description and understanding of ethnic relations in social work, teachers’ conception of students understanding of ethnic relations, and the content, form and strategies for teaching used by the teachers. The analysis is thematic and inspired from narrative analysis. The results show that the subject is relatively invisible in steering documents. The interviewees have experienced changes in the teaching over time, with less focus on intercultural relations and specific cultural competence. Instead ethnic relations are treated more contextually and interacting with categories as gender, class and age. The need of theoretical and critical knowledge of migration and ethnic relations in a broad sense but also for specific professional use is emphasized.

Keywords: ethnic relations, social work education, social change, human rights, equality, ethnic diversity in Sweden

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Authors: Susan E Orlovich

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Ongoing, effective teacher professional learning is acknowledged as a critical influence on teacher practice. However, it is unclear whether the elements of effective professional learning result in transformed teacher practice in the classroom. This research project is interested in 4C teacher professional learning. The professional learning practices to assist teachers in transforming their practice to integrate the 4C capabilities seldom feature in the academic literature. The 4Cs are a shorthand way of representing the concepts of communication, collaboration, creativity, and critical reflection and refer to the capabilities needed for deeper learning, personal growth, and effective participation in society. The New South Wales curriculum review (2020) acknowledges that identifying, teaching, and assessing the 4C capabilities are areas of challenge for teachers. However, it also recognises that it is essential for teachers to build the confidence and capacity to understand, teach and assess the capabilities necessary for learners to thrive in the 21st century. This qualitative research project explores the professional learning experiences of sixteen teachers in four different primaries (K-6) settings in Sydney, Australia, who are learning to integrate, teach and assess the 4Cs. The project draws on the Theory of Practice Architecture as a framework to analyse and interpret teachers' experiences in each site. The sixteen participants in the study are teachers from four primary settings and include early career, experienced, and teachers in leadership roles (including the principal). In addition, some of the participants are also teachers who are learning within a Community of Practice (CoP) as their school setting is engaged in a 4C professional learning, Community of Practice. Qualitative and arts-informed research methods are utilised to examine the cultural-discursive, social-political, and material-economic practice arrangements of the site, explore how these arrangements may have shaped the professional learning experiences of teachers, and in turn, influence the teaching practices of the 4Cs in the setting. The research is in the data analysis stage (October 2022), with preliminary findings pending. The research objective is to investigate the elements of the professional learning experiences undertaken by teachers to teach the 4Cs in the primary setting. The lens of practice architectures theory is used to identify the influence of the practice architectures on critical praxis in each site and examine how the practice arrangements enable or constrain the teaching of 4C capabilities. This research aims to offer deep insight into the practice arrangements which may enable or constrain teacher professional learning in the 4Cs. Such insight from this study may contribute to a better understanding of the practices that enable teachers to transform their practice to achieve the integration, teaching, and assessment of the 4C capabilities.

Keywords: 4Cs, communication, collaboration, creativity, critical reflection, teacher professional learning

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Authors: Vlad Andrei Raducanu, Mariana Lucia Angelescu, Ion Cinca, Vasile Danut Cojocaru, Doina Raducanu

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By using smart digital tools, such as generative design (GD) and digital fabrication (DF), problems of high actuality concerning resources optimization (materials, energy, time) can be solved and applications or products of free-form type can be created. In the new digital technology materials are active, designed in response to a set of performance requirements, which impose a total rethinking of old material practices. The article presents the design procedure key steps of a free-form architectural object - a column type one with connections to get an adaptive 3D surface, by using the parametric design methodology and by exploiting the properties of conventional metallic materials. In parametric design the form of the created object or space is shaped by varying the parameters values and relationships between the forms are described by mathematical equations. Digital parametric design is based on specific procedures, as shape grammars, Lindenmayer - systems, cellular automata, genetic algorithms or swarm intelligence, each of these procedures having limitations which make them applicable only in certain cases. In the paper the design process stages and the shape grammar type algorithm are presented. The generative design process relies on two basic principles: the modeling principle and the generative principle. The generative method is based on a form finding process, by creating many 3D spatial forms, using an algorithm conceived in order to apply its generating logic onto different input geometry. Once the algorithm is realized, it can be applied repeatedly to generate the geometry for a number of different input surfaces. The generated configurations are then analyzed through a technical or aesthetic selection criterion and finally the optimal solution is selected. Endless range of generative capacity of codes and algorithms used in digital design offers various conceptual possibilities and optimal solutions for both technical and environmental increasing demands of building industry and architecture. Constructions or spaces generated by parametric design can be specifically tuned, in order to meet certain technical or aesthetical requirements. The proposed approach has direct applicability in sustainable architecture, offering important potential economic advantages, a flexible design (which can be changed until the end of the design process) and unique geometric models of high performance.

Keywords: parametric design, algorithmic procedures, free-form architectural object, sustainable architecture

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Authors: Bruno C. Schimming, Leandro L. Martins, PatríCia F. F. Pinheiro, Raquel F. Domeniconi, FabríCio S. Oliveira

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The agouti is a wildlife rodent that can be used as an alternative source of animal protein and this species has been raised in captivity in Brazil with the aim of providing meat. Thus, the knowledge of their reproductive biology and morphology of the reproductive organs is important. The objective of this study was to describe the morphology of epididymis in the Azara’s agouti, by light microscopy. Samples of epididymis were obtained from five adult Azara’s agouti (Dasyprocta azarae) during castration surgery performed at the Municipal Zoo of Catanduva, Brazil. Fragments of the epididymal regions (initial segment, caput, corpus and cauda) were collected. The biological samples were immediately fixed in paraformaldehyde for 24 hours, followed by histologic procedures comprising embedding in ParaplastTM (Sigma, St. Louis, MO, USA), sections of 5 µm, and staining with HE and Masson’s trichrome. The epididymis was a highly convoluted tubule that links the testis to the vas deferens. The epithelium lining was pseudostratified columnar surrounded by a periductal stroma. The epithelium contains several cell types: principal, basal, apical, clear, and hallo cells. Principal cells were the most abundant cell type. There were observed also migratory cells named halo cells. The caput epididymis was divided into two different regions: initial segment and caput. The initial segment has a very wide lumen, a high epithelium with conspicuous microvilli and the lumen was wide with exfoliated material. The other region of the caput epididymis, showed a lower epithelium when compared with the initial segment, large amounts of spermatozoa in the lumen, and a cytoplasmic vacuolization. This region presented many narrows cells. Many spermatozoa appeared in the lumen of corpus epididymis. The cauda region had a lower epithelium than the other epididymal regions in the agouti. The cauda epithelium presented plicae protruding into the lumen. Large amounts of spermatozoa are also present in the lumen. Small microvilli uniformly arranged so as to form a kind of “brush border” are observed on the apical surface of the cauda epithelium. The pattern of the epithelium lining the duct of the agouti epididymis does not differ greatly from that reported to other mammals, such as domestic and wildlife animals. These findings can cooperate with future investigations especially those related to rational exploration of these animals. All experimental procedures were approved by the institutional ethics committee (CEUA 796/2015). This study was supported by FAPESP (Grants 2015/23822-1).

Keywords: wildlife, testis excurrent ducts, epididymis, morphology

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Authors: Pushp Lata Sankhwar

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INTRODUCTION: Maternal Hypothyroidism is the most frequent endocrine disorder in pregnancy and varies from 2.5% in the west to 11.0% in India. Maternal Hypothyroidism can have detrimental maternal effects like increased risk of preterm labor, PPROM leading to increased maternal morbidity and also on the neonate in the form of prematurity and its complications, prolonged hospital stay, neurological developmental problems, delayed milestones and mental retardation etc. Henceforth, the study was planned to evaluate the role of Hypothyroidism in preterm labor and its effect on neonates. AIMS AND OBJECTIVES: To Correlate Overt Hypothyroidism, Subclinical Hypothyroidism and Isolated Hypothyroxinemia With Preterm Labor and the neonatal outcome. Material and Methods: A case-control study of singleton pregnancy was performed over a year, in which a total of 500 patients presenting in the emergency with preterm labor were enrolled. The thyroid profile of these patients was sent at the time of admission, on the basis of which they were divided into Cases – Hypothyroidic mothers and Controls – Euthyroid mothers. The cases were further divided into subclinical, overt Hypothyroidism and isolated hypothyroxinemia. The neonatal outcome of these groups was also compared on the basis of the incidence and severity of neonatal morbidity, neonatal respiratory distress, the incidence of neonatal Hypothyroidism and early complications. The feto-maternal data was collected and analysed. RESULTS: In the study, a total of 500 antenatal patients with a history of preterm labor were enrolled, out of which 67 (13.8%) patients were found to be hypothyroid. The majority of the mothers had Subclinical Hypothyroidism (12.2%), followed by Overt Hypothyroidism seen in 1% of the mothers and isolated hypothyroxinemia in 0.6% of cases. The neonates of hypothyroid mothers had higher levels of cord blood TSH, and the mean cord blood TSH levels were highest in the case of neonates of mothers with Overt Hypothyroidism. The need for resuscitation of the neonates at the time of birth was higher in the case of neonates of hypothyroid mothers, especially with Subclinical Hypothyroidism. Also, it was found that the requirement of oxygen therapy in the form of oxygen by nasal prongs, oxygen by a hood, CPAP, CPAP along with surfactant therapy and mechanical ventilation along with surfactant therapy was significantly higher in the case of neonates of hypothyroid mothers. CONCLUSION: The results of our study imply that uncontrolled and untreated maternal Hypothyroidism may also lead to preterm delivery. The neonates of mothers with Hypothyroidism have higher cord blood TSH levels. The study also shows that there is an increased incidence and severity of respiratory distress in the neonates of hypothyroid mothers with untreated subclinical Hypothyroidism. Hence, we propose that routine screening for thyroid dysfunction in pregnant women should be done to prevent thyroid-related feto-maternal complications.

Keywords: high-risk pregnancy, thyroid, dysfunction, hypothyroidism, Preterm labor

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Authors: Sukhdev Singh, Baljinder Singh Bal, Amandeep Singh, Kanchan Thappa

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A nation's future almost certainly rests on the future of its children, and a nation's wellbeing can be greatly improved by providing for the right upbringing of its children. Participating in physical education and sports programmes is crucial for reaching one's full potential. As we are all aware, sports have recently become incredibly popular on a global scale. Sports are continually becoming more and more popular, and this positive trend is probably going to last for some time to come. Motor abilities will provide more accurate information on the developmental process of children. Motor fitness is a component of physical fitness that includes strength, speed, flexibility, and agility, and is related to enhanced performance and the development of motor skills. In recent years, there has been increased interest in the differences in child growth between urban and rural environments. Differences in student growth, body dimensions, body composition, and fitness levels due to urban and rural environmental disparities have come into focus in recent years. The main aim of this study is to know the differentials of motor fitness components among the school children of rural and urban areas of the Jammu region. Material and Methods: In total, sixty male subjects (mean ± SD; age, 16.475 ± 1.0124 yrs.; height, 172.8 ± 2.0153 cm; Weight, 59.75 ± 3.628 kg) from the Jammu region took part in the study. A minimum sample size of 40 subjects was obtained and was derived from Rural (N1=20) and Urban (N2=20) school-going children. Statistical Applications: The Statistical Package for the Social Sciences (SPSS) version 14.0 was used for all analyses. The differences in the mean of each group for the selected variable were tested for the significance of difference by an independent samples t-test. For testing the hypotheses, the level of significance was set at 0.05. Results: Results revealed that there were significant differences of leg explosive strength (p=0.0040*), dynamic balance (p=0.0056*), and Agility (p=0.0176*) among the School Children of the rural and urban areas of the Jammu region. However, Results further revealed that there were not significant differences of cardio respiratory endurance (p=0.8612), speed (p=0.2231), Low Back/Hamstring Flexibility (p=0.6478), and Two Hand Coordination. (p= 0.0953) among the School Children of the rural and urban areas of the Jammu region. Conclusion: The results of study showed that there is significance difference between Rural and Urban School children of the Jammu region with regards to a variable," leg explosive strength, dynamic balance, Agility” and the there is no significance difference between Rural and Urban School children of the Jammu region with regards variable “cardio-respiratory endurance, speed, Low Back/Hamstring Flexibility, Two Hand Coordination”.

Keywords: motor fitness, rural areas, school children, urban areas

Procedia PDF Downloads 76

Authors: Tom Elias, Kiran G. Shirlal

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Coastal erosion is one of the major issue faced by maritime countries, globally. More than 1200 km stretch of Indian coastline is marked eroding. There have been numerous attempts to impede the erosion rate and to attain equilibrium beach profiles. High cost and unavailability of natural rocks forced coastal engineers to find alternatives for conventional hard options like seawalls and groynes. Geosynthetic containment systems, emerged in the mid 20th century proved promising in catering coastal protection in countries like Australia, Germany and United States. The present study aims at reviewing Indian timeline of protection works that uses geosynthetic containment systems. Indian exploration regarding geosynthetic containment system dates back to early 2000s. Generally, protection structures use geosynthetics in the form of Geotubes, Geocontainers, and Geobags with Geotubes being most widely used in the form of submerged reefs, seawalls, groynes and breakwaters. Sand and dredged waste are used to fill these containment systems with calculated sand fill ratio. Reviewing the prominent protection works constructed in the east and west coast of India provides an insight into benefits and the difficulties faced by the practical installation. Initially, geosynthetic structures were considered as a temporary protection method prior to the construction of some other hard structure. Later Dahanu, Hamala and Pentha experiences helped in establishing geotubes as an alternative to conventional structures. Nearshore geotubes reefs aimed to attain equilibrium beach served its purpose in Hamala and Dahanu, Maharashtra, while reef constructed at Candolim, Goa underwent serious damage due to Toe Scour. In situ filling by pumping of sand slurry as in case of Shankarpur Seawall, West Bengal remains as a major concern. Geosynthetic systems supplemented by gabions and rock armours improves the wave dissipation, stability and reflection characteristics as implied in Pentha Coast, Odisha, Hazira, Gujarat and Uppada, Andhra Pradesh. Keeping improper design and deliberate destruction by vandals apart, geosynthetic containment systems offer a cost-effective alternative to conventional coastal protection methods in India. Additionally, geosynthetics supports marine growth in its surface which enhances its demand as an eco-friendly material and encourages usage.

Keywords: coastal protection, geotubes, geobags, geocontainers

Procedia PDF Downloads 151

Authors: Pantea Salehizadeh, Martin P. Bucknall, Robert Driscoll, Jayashree Arcot, George Srzednicki

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Banana is one of the most important crops produced in large quantities in tropical and sub-tropical countries. Of the total plant material grown, approximately 40% is considered waste and left in the field to decay. This practice allows fungal diseases such as Sigatoka Leaf Spot to develop, limiting plant growth and spreading spores in the air that can cause respiratory problems in the surrounding population. The pseudostem is considered a waste residue of production (60 to 80 tonnes/ha/year), although it is a good source of dietary fiber and volatile organic compounds (VOC’s). Strategies to process banana pseudostem into palatable, nutritious and marketable food materials could provide significant social and economic benefits. Extraction of VOC’s with desirable odor from dried and fresh pseudostem could improve the smell of products from the confectionary and bakery industries. Incorporation of banana pseudostem flour into bakery products could provide cost savings and improve nutritional value. The aim of this study was to determine the effects of drying methods and different banana species on the profile of volatile aroma compounds in dried banana pseudostem. The banana species analyzed were Musa acuminata and Musa balbisiana. Fresh banana pseudostem samples were processed by either freeze-drying (FD) or heat pump drying (HPD). The extraction of VOC’s was performed at ambient temperature using vacuum distillation and the resulting, mostly aqueous, distillates were analyzed using headspace solid phase microextraction (SPME) gas chromatography – mass spectrometry (GC-MS). Optimal SPME adsorption conditions were 50 °C for 60 min using a Supelco 65 μm PDMS/DVB Stableflex fiber1. Compounds were identified by comparison of their electron impact mass spectra with those from the Wiley 9 / NIST 2011 combined mass spectral library. The results showed that the two species have notably different VOC profiles. Both species contained VOC’s that have been established in literature to have pleasant appetizing aromas. These included l-Menthone, D-Limonene, trans-linlool oxide, 1-Nonanol, CIS 6 Nonen-1ol, 2,6 Nonadien-1-ol, Benzenemethanol, 4-methyl, 1-Butanol, 3-methyl, hexanal, 1-Propanol, 2-methyl- acid، 2-Methyl-2-butanol. Results show banana pseudostem VOC’s are better preserved by FD than by HPD. This study is still in progress and should lead to the optimization of processing techniques that would promote the utilization of banana pseudostem in the food industry.

Keywords: heat pump drying, freeze drying, SPME, vacuum distillation, VOC analysis

Procedia PDF Downloads 334

Authors: Mustafa Var, Yasin Kültiğin Yaman, Elif Berna Var, Müberra Pulatkan

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This study deals with real application of an urban transformation project in Trabzon, Turkey. It aims to highlight the significance of using native species in terms of planting design of transformation projects which will also promote sustainability of urban identity. Urban identity is a phenomenon shaped not only by physical, but also by natural, spatial, social, historical and cultural factors. Urban areas face with continuous change which can be whether positive or negative way. If it occurs in a negative way that may have some destructive effects on urban identity. To solve this problematic issue, urban renewal movements initally started after 1840s around the world especially in the cities with ports. This process later followed by the places where people suffered a lot from fires and has expanded to all over the world. In Turkey, those processes have been experienced mostly after 1980s as country experienced the worst effects of unplanned urbanization especially in 1950-1990 period. Also old squares, streets, meeting points, green areas, Ottoman bazaars have changed slowly. This change was resulted in alienation of inhabitants to their environments. As a solution, several actions were taken like Mass Housing Laws which was enacted in 1981 and 1984 or urban transformation projects. Although projects between 1990-2000 were tried to satisfy the expectations of local inhabitants by the help of several design solutions to promote cultural identity; unfortunately those modern projects has also been resulted in alienation of urban environments to the inhabitants. Those projects were initially done by TOKI (Housing Development Administration of Turkey) and later followed by the Ministry of Environment and Urbanization after 2011. Although they had significant potentials to create healthy urban environments, they could not use this opportunity in an effective way. The reason for their failure is that their architectural styles and planting designs are unrespectful to local identity and environments. Generally, it can be said that the most of the urban transformation projects implementing in Turkey nearly have no concerns about the locality. However, those projects can be used as a positive tool for enhanching the urban identity of cities by means of local planting material. For instance, Kyoto can be identified by Japanese Maple trees or Seattle can be specified by Dahlia. In the same way, in Turkey, Istanbul city can be identified by Judas and Stone Pine trees or Giresun city can be identified by Cherry trees. Thus, in this paper, the importance of conserving urban identity is discussed specificly with the help of using local planting elements. After revealing the mistakes that are made during urban transformation projects, the techniques and design criterias for preserving and promoting urban identity are examined. In the end, it is emphasized that every city should have their own original, local character and specific planting design which can be used for highlighting its identity as well as architectural elements.

Keywords: urban identity, urban transformation, planting design, landscape architecture

Procedia PDF Downloads 546

Authors: Dinesh Munjurulimana, Anil Tiwari, Tingwen Li, Carlos Pereira, Sreekanth Pannala, John Waters

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With the rapid transition to electric vehicles (EVs) across the globe, car manufacturers are in need of integrated and lightweight solutions for the battery packs of these vehicles. An integral part of a battery pack is the battery tray, which constitutes a significant portion of the pack’s overall weight. Based on the functional requirements, cost targets, and packaging space available, a range of materials –from metals, composites, and plastics– are often used to develop these battery trays. This paper considers the design and development of integrated thermoplastic-intensive battery trays, using the available packaging space from a representative EV battery pack. Presented as a proposed alternative are multiple concepts to integrate several connected systems such as cooling plates and underbody impact protection parts of a multi-piece incumbent battery pack. The resulting digital prototype was evaluated for several mechanical performance measures such as mechanical shock, drop, crush resistance, modal analysis, and torsional stiffness. The performance of this alternative design is then compared with the incumbent solution. In addition, insights are gleaned into how these novel approaches can be optimized to meet or exceed the performance of incumbent designs. Preliminary manufacturing feasibility of the optimal solution using injection molding and other commonly used manufacturing methods for thermoplastics is briefly explained. Then numerical and analytical evaluations are performed to show a representative Pareto front of cost vs. volume of the production parts. The proposed solution is observed to offer weight savings of up to 40% on a component level and part elimination of up to two systems in the battery pack of a typical battery EV while offering the potential to meet the required performance measures highlighted above. These conceptual solutions are also observed to potentially offer secondary benefits such as improved thermal and electrical isolations and be able to achieve complex geometrical features, thus demonstrating the ability to use the complete packaging space available in the vehicle platform considered. The detailed study presented in this paper serves as a valuable reference for researches across the globe working on the development of EV battery packs – especially those with an interest in the potential of employing alternate solutions as part of a mixed-material system to help capture untapped opportunities to optimize performance and meet critical application requirements.

Keywords: thermoplastics, lightweighting, part integration, electric vehicle battery packs

Procedia PDF Downloads 205

Authors: Benoit Atge, Alice Dhersin, Oscar Da Silva Cacao, Beatrice Martinez, Dominique Ducint, Catherine Verdun-Esquer, Isabelle Baldi, Mathieu Molimard, Antoine Villa, Mireille Canal-Raffin

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Introduction: Healthcare workers' exposure to antineoplastic drugs (AD) is a burning issue for occupational medicine practitioners. Biological monitoring of occupational exposure (BMOE) is an essential tool for assessing AD contamination of healthcare workers. In addition to BMOE, surface sampling is a useful tool in order to understand how workers get contaminated, to identify sources of environmental contamination, to verify the effectiveness of surface decontamination way and to ensure monitoring of these surfaces. The objective of this work was to develop a complete tool including a kit for surface sampling and a quantification analytical method for AD traces detection. The development was realized with the three following criteria: the kit capacity to sample in every professional environment (healthcare services, veterinaries, etc.), the detection of very low AD traces with a validated analytical method and the easiness of the sampling kit use regardless of the person in charge of sampling. Material and method: AD mostly used in term of quantity and frequency have been identified by an analysis of the literature and consumptions of different hospitals, veterinary services, and home care settings. The kind of adsorbent device, surface moistening solution and mix of solvents for the extraction of AD from the adsorbent device have been tested for a maximal yield. The AD quantification was achieved by an ultra high-performance liquid chromatography method coupled with tandem mass spectrometry (UHPLC-MS/MS). Results: With their high frequencies of use and their good reflect of the diverse activities through healthcare, 15 AD (cyclophosphamide, ifosfamide, doxorubicin, daunorubicin, epirubicin, 5-FU, dacarbazin, etoposide, pemetrexed, vincristine, cytarabine, methothrexate, paclitaxel, gemcitabine, mitomycin C) were selected. The analytical method was optimized and adapted to obtain high sensitivity with very low limits of quantification (25 to 5000ng/mL), equivalent or lowest that those previously published (for 13/15 AD). The sampling kit is easy to use, provided with a didactic support (online video and protocol paper). It showed its effectiveness without inter-individual variation (n=5/person; n= 5 persons; p=0,85; ANOVA) regardless of the person in charge of sampling. Conclusion: This validated tool (sampling kit + analytical method) is very sensitive, easy to use and very didactic in order to control the chemical risk brought by AD. Moreover, BMOE permits a focal prevention. Used in routine, this tool is available for every intervention of occupational health.

Keywords: surface contamination, sampling kit, analytical method, sensitivity

Procedia PDF Downloads 132

Authors: Sidharth Talan, Sanjay Kumar Sharma, Eoin Joseph Wallace, Nikita Agrawal

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Underground mining is at the core of rapidly evolving metals and minerals sector due to the increasing mineral consumption globally. Even though the surface mines are still more abundant on earth, the scales of industry are slowly tipping towards underground mining due to rising depth and complexities of orebodies. Thus, the efficient and productive functioning of underground operations depends significantly on the synchronized performance of key elements such as operating site, mining equipment, manpower and mine services. Production drilling is the process of conducting long hole drilling for the purpose of charging and blasting these holes for the production of ore in underground metal mines. Thus, production drilling is the crucial segment in the underground metal mining value chain. This paper presents the process mapping tool to evaluate the production drilling process in the underground metal mining operation by dividing the given process into three segments namely Input, Process and Output. The three segments are further segregated into factors and sub-factors. As per the study, the major input factors crucial for the efficient functioning of production drilling process are power, drilling water, geotechnical support of the drilling site, skilled drilling operators, services installation crew, oils and drill accessories for drilling machine, survey markings at drill site, proper housekeeping, regular maintenance of drill machine, suitable transportation for reaching the drilling site and finally proper ventilation. The major outputs for the production drilling process are ore, waste as a result of dilution, timely reporting and investigation of unsafe practices, optimized process time and finally well fragmented blasted material within specifications set by the mining company. The paper also exhibits the drilling loss matrix, which is utilized to appraise the loss in planned production meters per day in a mine on account of availability loss in the machine due to breakdowns, underutilization of the machine and productivity loss in the machine measured in drilling meters per unit of percussion hour with respect to its planned productivity for the day. The given three losses would be essential to detect the bottlenecks in the process map of production drilling operation so as to instigate the action plan to suppress or prevent the causes leading to the operational performance deficiency. The given tool is beneficial to mine management to focus on the critical factors negatively impacting the production drilling operation and design necessary operational and maintenance strategies to mitigate them. 

Keywords: process map, drilling loss matrix, SIPOC, productivity, percussion rate

Procedia PDF Downloads 215

Authors: Ikenna Stephen Ezennia, Sebnem Onal Hoscara

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Successive governments in Nigeria are faced with the pressing problem of how to house an ever-expanding urban population, usually low-income earners. The question of housing and affordability presents a complex challenge for these governments, as the commodification of housing links it inextricably to markets and capital flows. Therefore, placing it as at the center of the government’s agenda. However, the provision of decent and affordable housing for average Nigerians has remained an illusion, despite copious schemes, policies and programs initiated and carried out by various successive governments. Similarly, this phenomenon has also been observed in many countries of Africa, which is largely a result of economic unpredictability, lack of housing finance and insecurity, among other factors peculiar to a struggling economy. This study reviews recent dynamics and factors challenging the provision and development of affordable housing for the low income urban populace of Nigeria. Thus, the aim of the study is to present a comprehensive approach for understanding recent trends in the provision of affordable housing for Nigerians. The approach is based on a new paradigm of research: transdisciplinarity; a form of inquiry that crosses the boundaries of different disciplines. Therefore, the review takes a retrospective gaze at the various housing development programs/schemes/policies taken by successive governments of Nigeria within the last few decades and exams recent efforts geared towards eradicating the problems of housing delivery. Sources of data included relevant English language articles and the results of literature search of Elsevier Science Direct, ISI Web of Knowledge, Pro Quest Central, Scopus, and Google Scholar. The findings reveal that factors such as; rapid urbanization, inadequate planning and land use control, lack of adequate and favorable finance, high prices of land, high prices of building material, youth/touts harassment of developers, poor urban infrastructure, multiple taxation, and risk share are the major factors posing as a hindrance to adequate housing delivery. The results show that the majority of Nigeria’s affordable housing schemes, programs and policies are in most cases poorly implemented and abandoned without proper coordination. Consequently, the study concludes that the affordable housing delivery strategies in Nigeria are an epitome of lip service politics by successive governments; and the current trend of leaving housing provision to the vagaries of market forces cannot be expected to support affordable housing especially for the low income urban populace.

Keywords: affordable housing, housing delivery, national housing policy, urban poor

Procedia PDF Downloads 220

Authors: M. Kozłowski, M. Kadela

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Foamed concrete is known for its low self-weight and excellent thermal and acoustic properties. For many years, it has been used worldwide for insulation to foundations and roof tiles, as backfill to retaining walls, sound insulation, etc. However, in the last years it has become a promising material also for structural purposes e.g. for stabilization of weak soils. Due to favorable properties of foamed concrete, many interests and studies were involved to analyze its strength, mechanical, thermal and acoustic properties. However, these studies do not cover the investigation of fracture energy which is the core factor governing the damage and fracture mechanisms. Only limited number of publications can be found in literature. The paper presents the results of experimental investigation and numerical campaign of foamed concrete based on three-point bending test of beams with initial notch. First part of the paper presents the results of a series of static loading tests performed to investigate the fracture properties of foamed concrete of varying density. Beam specimens with dimensions of 100×100×840 mm with a central notch were tested in three-point bending. Subsequently, remaining halves of the specimens with dimensions of 100×100×420 mm were tested again as un-notched beams in the same set-up with reduced distance between supports. The tests were performed in a hydraulic displacement controlled testing machine with a load capacity of 5 kN. Apart from measuring the loading and mid-span displacement, a crack mouth opening displacement (CMOD) was monitored. Based on the load – displacement curves of notched beams the values of fracture energy and tensile stress at failure were calculated. The flexural tensile strength was obtained on un-notched beams with dimensions of 100×100×420 mm. Moreover, cube specimens 150×150×150 mm were tested in compression to determine the compressive strength. Second part of the paper deals with numerical investigation of the fracture behavior of beams with initial notch presented in the first part of the paper. Extended Finite Element Method (XFEM) was used to simulate and analyze the damage and fracture process. The influence of meshing and variation of mechanical properties on results was investigated. Numerical models simulate correctly the behavior of beams observed during three-point bending. The numerical results show that XFEM can be used to simulate different fracture toughness of foamed concrete and fracture types. Using the XFEM and computer simulation technology allow for reliable approximation of load–bearing capacity and damage mechanisms of beams made of foamed concrete, which provides some foundations for realistic structural applications.

Keywords: foamed concrete, fracture energy, three-point bending, XFEM

Procedia PDF Downloads 300

Authors: Fang Li, Jiazhao Wang, Jianmin Ma

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The practical application of Li-S batteries is hampered due to poor cycling stability caused by electrolyte-dissolved lithium polysulfides. Dual functionalities such as strong chemical adsorption stability and high conductivity are highly desired for an ideal host material for a sulfur-based cathode. Polypyrrole (PPy), as a conductive polymer, was widely studied as matrixes for sulfur cathode due to its high conductivity and strong chemical interaction with soluble polysulfides. Thus, a novel cathode structure consisting of a free-standing sulfur-polypyrrole cathode and a polypyrrole coated separator was designed for flexible Li-S batteries. The PPy materials show strong interaction with dissoluble polysulfides, which could suppress the shuttle effect and improve the cycling stability. In addition, the synthesized PPy film with a rough surface acts as a current collector, which improves the adhesion of sulfur materials and restrain the volume expansion, enhancing the structural stability during the cycling process. For further enhancing the cycling stability, a PPy coated separator was also applied, which could make polysulfides into the cathode side to alleviate the shuttle effect. Moreover, the PPy layer coated on commercial separator is much lighter than other reported interlayers. A soft-packaged flexible Li-S battery has been designed and fabricated for testing the practical application of the designed cathode and separator, which could power a device consisting of 24 light-emitting diode (LED) lights. Moreover, the soft-packaged flexible battery can still show relatively stable cycling performance after repeated bending, indicating the potential application in flexible batteries. A novel vapor phase deposition method was also applied to prepare uniform polypyrrole layer coated sulfur/graphene aerogel composite. The polypyrrole layer simultaneously acts as host and adsorbent for efficient suppression of polysulfides dissolution through strong chemical interaction. The density functional theory (DFT) calculations reveal that the polypyrrole could trap lithium polysulfides through stronger bonding energy. In addition, the deflation of sulfur/graphene hydrogel during the vapor phase deposition process enhances the contact of sulfur with matrixes, resulting in high sulfur utilization and good rate capability. As a result, the synthesized polypyrrole coated sulfur/graphene aerogel composite delivers a specific discharge capacity of 1167 mAh g⁻¹ and 409.1 mAh g⁻¹ at 0.2 C and 5 C respectively. The capacity can maintain at 698 mAh g⁻¹ at 0.5 C after 500 cycles, showing an ultra-slow decay rate of 0.03% per cycle.

Keywords: polypyrrole, strong chemical interaction, long-term stability, Li-S batteries

Procedia PDF Downloads 140

Authors: Ismatilla Mardanov

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There are three types of countries, the first of which is willing to attract foreign direct investment (FDI) in enormous amounts and do whatever it takes to make this happen. Therefore, FDI pours into such countries. In the second cluster of countries, even if the country is suffering tremendously from the shortage of investments, the governments are hesitant to attract investments because they are at the hands of local oligarchs/cartels. Therefore, FDI inflows are moderate to low in such countries. The third type is countries whose companies prefer investing in the most efficient locations globally and are hesitant to invest in the homeland. Sorting countries into such clusters, the present study examines the essential institutions and economic factors that make these countries different. Past literature has discussed various determinants of FDI in all kinds of countries. However, it did not classify countries based on government motivation, institutional setup, and economic factors. A specific approach to each target country is vital for corporate foreign direct investment risk analysis and decisions. The research questions are 1. What specific institutional and economic factors paint the pictures of the three clusters; 2. What specific institutional and economic factors are determinants of FDI; 3. Which of the determinants are endogenous and exogenous variables? 4. How can institutions and economic and political variables impact corporate investment decisions Hypothesis 1: In the first type, country institutions and economic factors will be favorable for FDI. Hypothesis 2: In the second type, even if country economic factors favor FDI, institutions will not. Hypothesis 3: In the third type, even if country institutions favorFDI, economic factors will not favor domestic investments. Therefore, FDI outflows occur in large amounts. Methods: Data come from open sources of the World Bank, the Fraser Institute, the Heritage Foundation, and other reliable sources. The dependent variable is FDI inflows. The independent variables are institutions (economic and political freedom indices) and economic factors (natural, material, and labor resources, government consumption, infrastructure, minimum wage, education, unemployment, tax rates, consumer price index, inflation, and others), the endogeneity or exogeneity of which are tested in the instrumental variable estimation. Political rights and civil liberties are used as instrumental variables. Results indicate that in the first type, both country institutions and economic factors, specifically labor and logistics/infrastructure/energy intensity, are favorable for potential investors. In the second category of countries, the risk of loss of assets is very high due to governmentshijacked by local oligarchs/cartels/special interest groups. In the third category of countries, the local economic factors are unfavorable for domestic investment even if the institutions are well acceptable. Cluster analysis and instrumental variable estimation were used to reveal cause-effect patterns in each of the clusters.

Keywords: foreign direct investment, economy, institutions, instrumental variable estimation

Procedia PDF Downloads 159

Authors: M. Beusink, E. W. C. Coenen

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The increased application of novel structural materials, such as high grade asphalt, concrete and laminated composites, has sparked the need for a better understanding of the often complex, non-linear mechanical behavior of such materials. The effective macroscopic mechanical response is generally dependent on the applied load path. Moreover, it is also significantly influenced by the microstructure of the material, e.g. embedded fibers, voids and/or grain morphology. At present, multiscale techniques are widely adopted to assess micro-macro interactions in a numerically efficient way. Computational homogenization techniques have been successfully applied over a wide range of engineering cases, e.g. cases involving first order and second order continua, thin shells and cohesive zone models. Most of these homogenization methods rely on Representative Volume Elements (RVE), which model the relevant microstructural details in a confined volume. Imposed through kinematical constraints or boundary conditions, a RVE can be subjected to a microscopic load sequence. This provides the RVE's effective stress-strain response, which can serve as constitutive input for macroscale analyses. Simultaneously, such a study of a RVE gives insight into fine scale phenomena such as microstructural damage and its evolution. It has been reported by several authors that the type of boundary conditions applied to the RVE affect the resulting homogenized stress-strain response. As a consequence, dedicated boundary conditions have been proposed to appropriately deal with this concern. For the specific case of a planar assumption for the analyzed structure, e.g. plane strain, axisymmetric or plane stress, this assumption needs to be addressed consistently in all considered scales. Although in many multiscale studies a planar condition has been employed, the related impact on the multiscale solution has not been explicitly investigated. This work therefore focuses on the influence of the planar assumption for multiscale modeling. In particular the plane stress case is highlighted, by proposing three different implementation strategies which are compatible with a first-order computational homogenization framework. The first method consists of applying classical plane stress theory at the microscale, whereas with the second method a generalized plane stress condition is assumed at the RVE level. For the third method, the plane stress condition is applied at the macroscale by requiring that the resulting macroscopic out-of-plane forces are equal to zero. These strategies are assessed through a numerical study of a thin walled structure and the resulting effective macroscale stress-strain response is compared. It is shown that there is a clear influence of the length scale at which the planar condition is applied.

Keywords: first-order computational homogenization, planar analysis, multiscale, microstrucutures

Procedia PDF Downloads 233

Authors: Esraa A. Khalil, Mohamed N. AbouZeid

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Building materials selection is critical for the sustainability of any project. The choice of building materials has a huge impact on the built environment and cost of projects. Building materials emit huge amount of carbon dioxide (CO₂) due to the use of cement as a basic component in the manufacturing process and as a binder, which harms our environment. Energy consumption from buildings has increased in the last few years; a huge amount of energy is being wasted from using unsustainable building and finishing materials, as well as from the process of heating and cooling of buildings. In addition, the construction sector in Egypt is taking a good portion of the economy; however, there is a lack of awareness of buildings environmental impacts on the built environment. Using advanced building materials and different wall systems can help in reducing heat consumption, the project’s initial and long-term costs, and minimizing the environmental impacts. Red Bricks is one of the materials that are being used widely in Egypt. There are many other types of bricks such as Autoclaved Aerated Concrete (AAC); however, the use of Red Bricks is dominating the construction industry due to its affordability and availability. This research focuses on the New Egyptian Administrative Capital as a case study to investigate the potential of the influence of using different wall systems such as AAC on the project’s cost and the environment. The aim of this research is to conduct a comparative analysis between the traditional and most commonly used bricks in Egypt, which is Red Bricks, and AAC wall systems. Through an economic and environmental study, the difference between the two wall systems will be justified to encourage the utilization of uncommon techniques in the construction industry to build more affordable, energy efficient and sustainable buildings. The significance of this research is to show the potential of using AAC in the construction industry and its positive influences. The study analyzes the factors associated with choosing suitable building materials for different projects according to the need and criteria of each project and its nature without harming the environment and wasting materials that could be saved or recycled. The New Egyptian Administrative Capital is considered as the country’s new heart, where ideas regarding energy savings and environmental benefits are taken into consideration. Meaning that, Egypt is taking good steps to move towards more sustainable construction. According to the analysis and site visits, there is a potential in reducing the initial costs of buildings by 12.1% and saving energy by using different techniques up to 25%. Interviews with the mega structures project engineers and managers reveal that they are more open to introducing sustainable building materials that will help in saving the environment and moving towards green construction as well as to studying more effective techniques for energy conservation.

Keywords: AAC blocks, building material, environmental impact, modern construction, new Egyptian administrative capital

Procedia PDF Downloads 121

Authors: Marc Romero-Estonllo, Judith Ramos-Castro, Yaiza San Miguel, Beatriz Rodríguez-Garrido, Carmela Monterroso

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Mining activity is among the main sources of trace and heavy metal(loid) pollution worldwide, which is a hazard to human and environmental health. That is why several projects have been emerging for the remediation of such polluted places. Phytomanagement strategies draw good performances besides big side benefits. In this work, a glasshouse assay with trace element polluted soils from an old Cu mine ore (NW of Spain) which forms part of the PhytoSUDOE network of phytomanaged contaminated field sites (PhytoSUDOE Project (SOE1/P5/E0189)) was set. The objective was to evaluate improvements induced by the following phytoremediation-related treatments. Three increasingly complex amendments alone or together with plant growth (Populus nigra L. alone and together with Tripholium repens L.) were tested. And three different rhizosphere bioinocula were applied (Plant Growth Promoting Bacteria (PGP), mycorrhiza (MYC), or mixed (PGP+MYC)). After 110 days of growth, plants were collected, biomass was weighed, and tree length was measured. Physical-chemical analyses were carried out to determine pH, effective Cation Exchange Capacity, carbon and nitrogen contents, bioavailable phosphorous (Olsen bicarbonate method), pseudo total element content (microwave acid digested fraction), EDTA extractable metals (complexed fraction), and NH4NO3 extractable metals (easily bioavailable fraction). On plant material, nitrogen content and acid digestion elements were determined. Amendment usage, plant growth, and bioinoculation were demonstrated to improve soil fertility and/or plant health within the time span of this study. Particularly, pH levels increased from 3 (highly acidic) to 5 (acidic) in the worst-case scenario, even reaching 7 (neutrality) in the best plots. Organic matter and pH increments were related to polluting metals’ bioavailability decrements. Plants grew better both with the most complex amendment and the middle one, with few differences due to bioinoculation. Using the less complex amendment (just compost) beneficial effects of bioinoculants were more observable, although plants didn’t thrive very well. On unamended soils, plants neither sprouted nor bloomed. The scheme assayed in this study is suitable for phytomanagement of these kinds of soils affected by mining activity. These findings should be tested now on a larger scale.

Keywords: aided phytoremediation, mine pollution, phytostabilization, soil pollution, trace elements

Procedia PDF Downloads 66

Authors: Andrey A. Lipovskii, Alexey V. Redkov, Vyacheslav V. Rusan, Dmitry K. Tagantsev, Valentina V. Zhurikhina

Abstract:

The presented research is related to the development of recently proposed technique of the formation of composite materials, like optical glass-ceramics, with predetermined structure and properties of the crystalline component. The technique is based on the control of the size and concentration of the crystalline grains using the phenomenon of glass-ceramics decrystallization (vitrification) induced by ion-exchange. This phenomenon was discovered and explained in the beginning of the 2000s, while related theoretical description was given in 2016 only. In general, the developed theory enables one to model the process and optimize the conditions of ion-exchange processing of glass-ceramics, which provide given properties of crystalline component, in particular, profile of the average size of the crystalline grains. The optimization is possible if one knows two dimensionless parameters of the theoretical model. One of them (β) is the value which is directly related to the solubility of crystalline component of the glass-ceramics in the glass matrix, and another (γ) is equal to the ratio of characteristic times of ion-exchange diffusion and crystalline grain dissolution. The presented study is dedicated to the development of experimental technique and simulation which allow determining these parameters. It is shown that these parameters can be deduced from the data on the space distributions of diffusant concentrations and average size of crystalline grains in the glass-ceramics samples subjected to ion-exchange treatment. Measurements at least at two temperatures and two processing times at each temperature are necessary. The composite material used was a silica-based glass-ceramics with crystalline grains of Li2OSiO2. Cubical samples of the glass-ceramics (6x6x6 mm3) underwent the ion exchange process in NaNO3 salt melt at 520 oC (for 16 and 48 h), 540 oC (for 8 and 24 h), 560 oC (for 4 and 12 h), and 580 oC (for 2 and 8 h). The ion exchange processing resulted in the glass-ceramics vitrification in the subsurface layers where ion-exchange diffusion took place. Slabs about 1 mm thick were cut from the central part of the samples and their big facets were polished. These slabs were used to find profiles of diffusant concentrations and average size of the crystalline grains. The concentration profiles were determined from refractive index profiles measured with Max-Zender interferometer, and profiles of the average size of the crystalline grains were determined with micro-Raman spectroscopy. Numerical simulation were based on the developed theoretical model of the glass-ceramics decrystallization induced by ion exchange. The simulation of the processes was carried out for different values of β and γ parameters under all above-mentioned ion exchange conditions. As a result, the temperature dependences of the parameters, which provided a reliable coincidence of the simulation and experimental data, were found. This ensured the adequate modeling of the process of the glass-ceramics decrystallization in 520-580 oC temperature interval. Developed approach provides a powerful tool for fine tuning of the glass-ceramics structure, namely, concentration and average size of crystalline grains.

Keywords: diffusion, glass-ceramics, ion exchange, vitrification

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Authors: Burçak Boztemur, Yue Xu, Laima Luo, M. Lütfi Öveçoğlu, Duygu Ağaoğulları

Abstract:

Tungsten (W) is used chiefly as plasma-facing material. However, it has some problems, such as brittleness after plasma exposure. High-entropy alloys (RHEAs) are a new opportunity for this deficiency. So, the neutron shielding behavior of WNbMoVTa and WNbMoVTaCr₀.₅Al compositions were examined against He⁺ irradiation in this study. The mechanical and irradiation properties of the WNbMoVTa base composition were investigated by adding the Al and Cr elements. The mechanical alloying (MA) for 6 hours was applied to obtain RHEA powders. According to the X-ray diffraction (XRD) method, the body-centered cubic (BCC) phase and NbTa phase with a small amount of WC impurity that comes from vials and balls were determined after 6 h MA. Also, RHEA powders were consolidated with the spark plasma sintering (SPS) method (1500 ºC, 30 MPa, and 10 min). After the SPS method, (Nb,Ta)C and W₂C₀.₈₅ phases were obtained with the decomposition of WC and stearic acid that is added during MA based on XRD results. Also, the BCC phase was obtained for both samples. While the Al₂O₃ phase with a small intensity was seen for the WNbMoVTaCr₀.₅Al sample, the Ta₂VO₆ phase was determined for the base sample. These phases were observed as three different regions according to scanning electron microscopy (SEM). All elements were distributed homogeneously on the white region by measuring an electron probe micro-analyzer (EPMA) coupled with a wavelength dispersive spectroscope (WDS). Also, the grey region of the WNbMoVTa sample was rich in Ta, V, and O elements. However, the amount of Al and O elements was higher for the grey region of the WNbMoVTaCr₀.₅Al sample. The high amount of Nb, Ta, and C elements were determined for both samples. Archimedes’ densities that were measured with alcohol media were closer to the theoretical densities of RHEAs. These values were important for the microhardness and irradiation resistance of compositions. While the Vickers microhardness value of the WNbMoVTa sample was measured as ~11 GPa, this value increased to nearly 13 GPa with the WNbMoVTaCr₀.₅Al sample. These values were compatible with the wear behavior. The wear volume loss was decreased to 0.16×10⁻⁴ from 1.25×10⁻⁴ mm³ by the addition of Al and Cr elements to the WNbMoVTa. The He⁺ irradiation was conducted on the samples to observe surface damage. After irradiation, the XRD patterns were shifted to the left because of defects and dislocations. He⁺ ions were infused under the surface, so they created the lattice expansion. The peak shifting of the WNbMoVTaCr₀.₅Al sample was less than the WNbMoVTa base sample, thanks to less impact. A small amount of fuzz was observed for the base sample. This structure was removed and transformed into a wavy structure with the addition of Cr and Al elements. Also, the deformation hardening was actualized after irradiation. A lower amount of hardening was obtained with the WNbMoVTaCr₀.₅Al sample based on the changing microhardness values. The surface deformation was decreased in the WNbMoVTaCr₀.₅Al sample.

Keywords: refractory high entropy alloy, microhardness, wear resistance, He⁺ irradiation

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Authors: Paulette Henry

Abstract:

If Caribbean Universities wish to remain sustainable in the global education market they must meet the new demands of the 21st Centuries learners. This means preparing the teaching and learning environment with the human and material and resources so that the University can blossom out into the entrepreneurial University. The entrepreneurial University prepares the learner to become a global citizen, one who is innovative and a critical thinker and has the competencies to create jobs. Entrepreneurship education provides more equitable access to university education building capacity for the local and global economy. The entrepreneurial thinking, the mindset, must therefore be among academic and support staff as well as students. In developing countries where resources are scarce, Universities are grappling with a myriad of financial and non-financial issues. These include increasing costs, Union demands for increased remuneration for staff and reduced subvention from governments which has become the norm. In addition, there is the political pressure against increasing tuition fees and the perceptions on the moral responsibilities of universities in national development. The question is how do small universities carve out their niche, meet both political and consumer demands for a high quality, low lost education, fulfil their development mandate and still remain not only viable but competitive. Themes which are central to this discourse on the transitions necessary for the entrepreneurial university are leadership, governance and staff well-being. This paper therefore presents a case study of a Caribbean University to show how transformational leadership and the change management framework propels change towards an entrepreneurial institution seeking to have a competitive advantage despite its low resourced context. Important to this discourse are the transformational approaches used by the University to prepare staff to move from their traditional psyche to embracing an entrepreneurial mindset whilst equipping students within the same mode to become work ready and creative global citizens. Using the mixed methods approach, opinions were garnered from both members of the University community as well as external stakeholder groups on their perception of the role of the University in the business arena and as a primary stakeholder in national development. One of the critical concepts emanating from the discourse was the need to change the mindset of the those in university governance as well as how national stakeholders engage the university. This paper shows how multiple non-financial factors can contribute to change. A combination of transformational and servant leadership, strengthened institutional structures and developing new ones, rebuilding institutional trust and pride have been among the strategies employed within the change management framework. The university is no longer limited by borders but through international linkages has transcended into a transnational stakeholder.

Keywords: competitiveness, context, entrepreneurial, leadership

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