2,442 research outputs found

    Deep tillage tool optimization by means of finite element method: Case study for a subsoiler tine

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    Technologies and computer capacity currently available allow us to employ design software and numerical methods to solve complicated problems in very wide disciplines of engineering. It is also important for researches in agriculture. This study focused on obtaining optimum geometry parameters of a subsoiler tine by using computer aided engineering (CAE) applications. A field experiment was conducted to determine draft force of the subsoiler. The results from the experimental study were used in the finite element analysis (FEA) to simulate stress distributions on the subsoiler tine. The maximum equivalent stress of 432.49 MPa was obtained in the FEA. Visual investigations and FEA results showed that according to the tine’s material yield stress point of 355 MPa, plastic deformation was evident. Based on the FEA results, an optimization study was undertaken to obtain optimum geometry parameters without the occurrence of plastic deformation. According to the optimization study results, the optimum parameters of the tine geometry and maximum equivalent stress of 346.61 MPa were obtained. In addition to this, the total mass of the tine was reduced by about 0.367 kg

    Peridynamic simulations of nanoindentation tests to determine elastic modulus of polymer thin films

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    This study combines atomic force microscope (AFM) nanoindentation tests and peridynamic (PD) simulations to extract the elastic moduli of polystyrene (PS) films with varying thicknesses. AFM nanoindentation tests are applied to relatively hard PS thin films deposited on soft polymer (polydimethylsiloxane (PDMS)) substrates. Linear force versus deformation response was observed in nanoindentation experiments and numerical simulations since the soft PDMS substrate under the stiff PS films allowed bending of thin PS films instead of penetration of AFM tip towards the PS films. The elastic moduli of PS thin films are found to be increasing with increasing film thickness. The validity of both the simulation and experimental results is established by comparison against those previously published in the literature

    Teaching Approaches and Practices of Student Teachers in Early Childhood Education: A Convergent Mixed Methods Study

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    This study examined the teaching approaches and practices of student teachers in early childhood education using a convergent parallel mixed methods design. The participants were 112 student teachers for the quantitative strand and 29 randomly selected student teachers for the qualitative strand of the study. Participants reported on their teaching approaches in the quantitative strand, and video recordings of teaching practices of student teachers were used in the qualitative strand of the study. Quantitative data were analyzed using cluster analyses, and qualitative data were analyzed using an observational coding of behaviors, following that which the quantitative and qualitative results were merged. Cluster analyses showed that student teachers to be categorized into three groups (traditional, constructivist, and mixed) that reflect their teaching approaches. The qualitative analyses from the video recordings consistently showed that student teachers reflected their perceptions of teaching approaches in their practice. Findings from the current study highlight the importance of understanding student teachers’ teaching approaches and practices in early childhood

    A Potential Research Area Under Shadow In Engineering:Agricultural Machinery Design and Manufacturing

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    As a branch of the global machinery industry, the agricultural (farm) machinery design and manufacturing or agricultural engineering industry has become one of the most important industries to be supported and focussed on in the era of hunger threats foreseen in the World’s future. In order to produce sufficient volumes of food from current limited agricultural land, well-designed machinery and high technology-supported mechanisation of the agricultural production processes is a vital necessity. However, although novel improvements are observed in this area, they are very limited. There is a lack of implementation of advanced engineering design and manufacturing technologies in this industry, therefore agricultural engineering could be considered a potential engineering research area with this in mind. This study aims to highlight the potential, gaps, sector specific challenges and limitations of the agricultural engineering research area at a macro level. Under consideration of the sector-specific indicators, the study revealed a major result: there is an insufficient level of sector-specific research on implementation strategies for up-to-date design and manufacturing technologies

    Design and structural optimisation of a tractor mounted telescopic boom crane

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    In this research, an application algorithm, which can be used in computer-aided design/engineering (CAD/CAE) and structural optimisation-based design studies of agricultural machineries, is introduced. This developed algorithm has been put in practice in a case study for a tractor mounted telescopic boom crane. The algorithm consists of both numerical and experimental methods and it includes material testing, three-dimensional (3D) computer-aided design and finite-element method (FEM)-based analysis procedures, structural optimisation strategy, physical prototyping, physical testing and design validation procedures. Following the visual and physical validation procedures carried out in the case study, the crane’s physical prototype was manufactured and the optimised design was approved for ongoing production. The study provides a unique CAD/CAE and experimentally driven total design pathway for similar products, which contributes to further research into the utilisation of engineering simulation technology for agricultural machinery design, analysis and related manufacturing subjects

    Prevalence and antibiotic susceptibility of Mycoplasma hominis and Ureaplasma urealyticum in pregnant women

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    SummaryBackgroundMycoplasma hominis and Ureaplasma urealyticum are important opportunistic pathogens implicated in urogenital infections and complicated pregnancy. We aimed to study the role of these pathogens in symptomatic and asymptomatic pregnant women and determine their clinical significance and antibiotic susceptibility.MethodsOne hundred pregnant women were included in the study, 50 symptomatic patients and 50 asymptomatic controls. Duplicate endocervical samples were taken from each individual and analyzed using the Mycoplasma IST-2 kit and A7 agar medium. Antimicrobial susceptibility was tested against doxycycline, josamycin, ofloxacin, erythromycin, tetracycline, ciprofloxacin, azithromycin, clarithromycin, and pristinamycin using the Mycoplasma IST-2 kit.ResultsTwelve symptomatic pregnant women had spontaneous abortions. Of these, eight (66.7%) cases had been colonized with M. hominis and/or U. urealyticum. Of the pregnant women infected with M. hominis and/or U. urealyticum, 40.7% delivered a low birth weight infant. M. hominis was successfully cultured in five women (5%) and U. urealyticum in 27 (27%). Among positive cultures, 15.6% and 84.4% of isolates were M. hominis and U. urealyticum, respectively. M. hominis and U. urealyticum were uniformly susceptible to doxycycline, tetracycline, and pristinamycin, which may be successfully used in the empirical therapy of infected individuals.ConclusionsIt can be concluded that genital colonization with M. hominis and U. urealyticum may predispose to spontaneous abortion and low birth weight

    Genome-wide SNP discovery and QTL mapping for fruit quality traits in inbred backcross lines (IBLs) of solanum pimpinellifolium using genotyping by sequencing

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    Background: Solanum pimpinellifolium has high breeding potential for fruit quality traits and has been used as a donor in tomato breeding programs. Unlocking the genetic potential of S. pimpinellifolium requires high-throughput polymorphism identification protocols for QTL mapping and introgression of favourable alleles into cultivated tomato by both positive and background selection. Results: In this study we identified SNP loci using a genotyping by sequencing (GBS) approach in an IBL mapping population derived from the cross between a high yielding fresh market tomato and S. pimpinellifolium (LA1589) as the recurrent and donor parents, respectively. A total of 120,983,088 reads were generated by the Illumina HiSeq next-generation sequencing platform. From these reads 448,539 sequence tags were generated. A majority of the sequence tags (84.4%) were uniquely aligned to the tomato genome. A total of 3.125 unique SNP loci were identified as a result of tag alignment to the genome assembly and were used in QTL analysis of 11 fruit quality traits. As a result, 37 QTLs were identified. S. pimpinellifolium contributed favourable alleles for 16 QTLs (43.2%), thus confirming the high breeding potential of this wild species. Conclusions: The present work introduced a set of SNPs at sufficiently high density for QTL mapping in populations derived from S. pimpinellifolium (LA1589). Moreover, this study demonstrated the high efficiency of the GBS approach for SNP identification, genotyping and QTL mapping in an interspecific tomato population.Scientific and Technological Research Council of Turkey (TUBITAK 114Z116

    Examining the environmental aspect of economic complexity outlook and environmental-related technologies in the Nordic states

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    Understanding the outlook of countries’ economic complexity is vital for assessing the future of industries’ product characterization. It provides opportunity and insight on how to mitigate the negative externalities that arises from the increasing pressure on the ecosystem. Based on this account, the effect of economic complexity and the corresponding outlook on environmental degradation vis-a-vis greenhouse gas (GHG) emissions alongside other environmental indicators are examined for the panel of Denmark, Finland, Norway, and Sweden for the period 1995 to 2020. After employing Driscoll- Kraay’s standard errors for random effect (RE) with individual effects for the examination, the results indicate that the region’s level of economic complexity favors environmental sustainability. Contrarily, the economic complexity outlook spurs GHG emissions, thus suggesting that future performance of the region’s economic complexity could be detrimental to its ecosystem. Another similar, and undesirable observation is that the increase in urban population hampers environmental quality as it causes a surge in GHG emissions. Meanwhile, the results then conclude that economic growth, economic complexity, and environmental-related technologies are found to be potent drivers of environmental sustainability as the indicators exert negative pressure on GHG emissions in the Nordic region. Important policies that potentially guide immediate, and future sector-wide activities toward enhancing the region’s sustainable development programs are posited through the study outcome.publishedVersio

    Use of Shear Wave Elastography in Pediatric Musculoskeletal Disorders

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    Muscle shear-wave elastography (SWE) is an exciting and rapidly evolving ultrasound technique that allows quantification of muscle stiffness with a non-invasive, non-painful and non-irradiating examination. It has the potential of wider clinical use due to relatively low-cost, providing real-time measurement and, especially for the pediatric population, taking less time and sedation/anesthesia-free. Research indicate that muscle SWE shows promise as an adjunct clinical tool for differentiating between a normal and an abnormal muscle, monitoring the effectiveness of therapeutic interventions, altering the therapeutic intervention, or deciding treatment duration. This chapter will aim to provide an overview of the knowledge about the using of muscle SWE in common pediatric musculoskeletal disorders such as Duchenne Muscular Dystrophy, Cerebral Palsy, Adolescent Idiopathic Scoliosis, and Congenital Muscular Torticollis in the light of current evidence

    Design and Additive Manufacturing of a Medical Face Shield for Healthcare Workers Battling Coronavirus (COVID-19)

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    During the coronavirus disease-19 pandemic, the demand for specific medical equipment such as personal protective equipment has rapidly exceeded the available supply around the world. Specifically, simple medical equipment such as medical gloves, aprons, goggles, surgery masks, and medical face shields have become highly in demand in the health-care sector in the face of this rapidly developing pandemic. This difficult period strengthens the social solidarity to an extent parallel to the escalation of this pandemic. Education and government institutions, commercial and noncommercial organizations and individual homemakers have produced specific medical equipment by means of additive manufacturing (AM) technology, which is the fastest way to create a product, providing their support for urgent demands within the health-care services. Medical face shields have become a popular item to produce, and many design variations and prototypes have been forthcoming. Although AM technology can be used to produce several types of noncommercial equipment, this rapid manufacturing approach is limited by its longer production time as compared to conventional serial/mass production and the high demand. However, most of the individual designer/maker-based face shields are designed with little appreciation of clinical needs and nonergonomic. They also lack of professional product design and are not designed according to AM (Design for AM [DfAM]) principles. Consequently, the production time of up to 4 – 5 h for some products of these designs is needed. Therefore, a lighter, more ergonomic, single frame medical face shield without extra components to assemble would be useful, especially for individual designers/makers and noncommercial producers to increase productivity in a shorter timeframe. In this study, a medical face shield that is competitively lighter, relatively more ergonomic, easy to use, and can be assembled without extra components (such as elastic bands, softening materials, and clips) was designed. The face shield was produced by AM with a relatively shorter production time. Subsequently, finite element analysis-based structural design verification was performed, and a three-dimensional (3D) prototype was produced by an original equipment manufacturer 3D printer (Fused Deposition Modeling). This study demonstrated that an original face shield design with <10 g material usage per single frame was produced in under 45 min of fabrication time. This research also provides a useful product DfAM of simple medical equipment such as face shields through advanced engineering design, simulation, and AM applications as an essential approach to battling coronavirus-like viral pandemics
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