Search results for: creep mechanisms

Authors: Wenjun Zhang, Yunqing Du, Steven W. Cranford, Ming L. Wang

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The beginning of 21st century has witnessed new advancements in the design and use of new materials for biosensing applications, from nano to macro, protein to tissue. Traditional analytical methods lack a complete toolset to describe the complexities introduced by living systems, pathological relations, discrete hierarchical materials, cross-phase interactions, and structure-property dependencies. Materiomics – via systematic molecular dynamics (MD) simulation – can provide structure-process-property relations by using a materials science approach linking mechanisms across scales and enables oriented biosensor design. With this approach, DNA biosensors can be utilized to detect disease biomarkers present in individuals’ breath such as acetone for diabetes. Our wireless sensor array based on single-stranded DNA (ssDNA)-decorated single-walled carbon nanotubes (SWNT) has successfully detected trace amount of various chemicals in vapor differentiated by pattern recognition. Here, we present how MD simulation can revolutionize the way of design and screening of DNA aptamers for targeting biomarkers related to oral diseases and oral health monitoring. It demonstrates great potential to be utilized to build a library of DNDA sequences for reliable detection of several biomarkers of one specific disease, and as well provides a new methodology of creating, designing, and applying of biosensors.

Keywords: biosensor, DNA, biomarker, molecular dynamics simulation

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Authors: H. C. Woo, F. Bouanis, C. S. Cojocaur

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Graphene, which consists of a single layer of carbon atoms in a honeycomb lattice, is an interesting potential optoelectronic material because of graphene’s high carrier mobility, zero bandgap, and electron–hole symmetry. Graphene can absorb light and convert it into a photocurrent over a wide range of the electromagnetic spectrum, from the ultraviolet to visible and infrared regimes. Over the last several years, a variety of graphene-based photodetectors have been reported, such as graphene transistors, graphene-semiconductor heterojunction photodetectors, graphene based bolometers. It is also reported that there are several physical mechanisms enabling photodetection: photovoltaic effect, photo-thermoelectric effect, bolometric effect, photogating effect, and so on. In this work, we report a simple approach for the realization of graphene based resistive photo-detection devices and the measurements of their photoelectrical response. The graphene were synthesized directly on the glass substrate by novel growth method patented in our lab. Then, the metal electrodes were deposited by thermal evaporation on it, with an electrode length and width of 1.5 mm and 300 μm respectively, using Co to fabricate simple graphene based resistive photosensor. The measurements show that the graphene resistive devices exhibit a photoresponse to the illumination of visible light. The observed re-sistance response was reproducible and similar after many cycles of on and off operations. This photoelectrical response may be attributed not only to the direct photocurrent process but also to the desorption of oxygen. Our work shows that the simple graphene resistive devices have potential in photodetection applications.

Keywords: graphene, resistive sensor, optoelectronics, photoresponse

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Authors: Khaleed Alsufyyan

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This doctoral research has been successfully approved by a specialist upgrade panel, and it presents the proposition that the KSA policy for combating maritime terrorism is inadequate and current governance frameworks, including laws, are insufficiently developed to respond effectively and fairly to maritime terrorism. It will examine the legal system in the KSA in terms of effectiveness fairness, as well as investigate this proposition to determine what factors have contributed to such a deficiency. The main focus of this research will draw upon the policies, laws, and practices of the KSA, as well as UK and international laws and policies, to assess whether it is feasible to apply them in the context of the KSA. This thesis will recommend strategies regarding maritime terrorism to enrich the legal and policy frameworks and address the current and future dynamics of maritime terrorism adequately. To derive suitable improvements, UK policies, laws, and practices will be considered for policy transfer purposes. As for studies focused on the KSA, since the KSA is a Muslim state, it will be important to assess the impact of Islamic Law or Sharia Law subject to the doctrines of fairness and effectiveness to comprehend how the KSA’s legal system operates and determine the boundaries it sets for the response to maritime terrorism. This thesis will propose that more reforms are needed to effectively and fairly deal with maritime terrorism based on the prevailing understanding of Sharia law. The research will address the international perspectives on the problem of maritime terrorism and international cooperation of the KSA regarding maritime terrorism and consider the need for further developments.

Keywords: maritime terrorism, maritime security, combat maritime terrorism in the KSA, protecting maritime transport against terrorism

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Authors: Jitendra Narayan Panda, Jayashree Bijwe, Raj K. Pandey

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PAEK (Polyaryl ether ketone) being a high-performance polymer, is currently being explored for its tribo-potential by incorporating various fibers, solid lubricants. In this work, influence of amount (30 and 40 %) of short glass fibers (GF) in two composites containing PAEK (60 and 50 %) and synthetic graphite (10 %) on mechanical and tribological behaviour was studied. The composites were developed by injection molding and evaluated in adhesive wear mode (pin on disc configuration) against mild steel disc. The load and speed were selected as variable input parameters while coefficient of friction (µ), specific wear rate (K0) and PVlimit (pressure × velocity) values were selected as output parameters for performance evaluation. Although higher amount of GF lead to better mechanical properties, tribological properties were not in tune to this. Overall, µ and K0 for both composites were in the range 0.04-0.08 and 3-8x 10-16 m3/Nm respectively and decreased with increase in applied PV values till failure was observed. PVlimit was indicated by 112 and 100 MPa m/s. Such high PVlimit values are not reported for any polymer composites running in dry conditions in the literature. The mechanical properties of the C40 composite (40 % GF) proved superior to C30 composite (30 % GF). However, all tribological properties of C40 were inferior to C30. It exhibited higher µ, higher K0 and slightly lower PVlimit value. The higher % fibers proved detrimental for tribo-performance and worn surface analysis by SEM & EDAX was done on the discs & pins to understand wear mechanisms.

Keywords: PAEK composites, pin-on-disk, PV limit, friction

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Authors: Sandor Levai, Valentin Juhasz, Miklos Gasz

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Rising damp is an extremely complex phenomenon that is of great practical interest to the field of building conservation due to the irreversible damages it can make to old and historic structures. The electrical effects occurring in damp masonry have been scarcely researched and are a largely unknown aspect of rising damp. Present paper describes the typical electrical patterns occurring in porous brickwork during a wetting and drying cycle. It has been found that in contrast with dry masonry, where electrical phenomena are virtually non-existent, damp masonry exhibits a wide array of electrical effects. Long-term real-time measurements performed in the lab on small-scale brick structures, using an array of embedded micro-sensors, revealed significant voltage, current, capacitance and resistance variations which can be linked to the movement of moisture inside porous materials. The same measurements performed on actual old buildings revealed a similar behaviour, the electrical effects being more significant in areas of the brickwork affected by rising damp. Understanding these electrical phenomena contributes to a better understanding of the driving mechanisms of rising damp, potentially opening new avenues of dealing with it in a less invasive manner.

Keywords: brick masonry, electrical phenomena in damp brickwork, porous building materials, rising damp, spontaneous electrical potential, wetting-drying cycle

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Authors: Dong Il Shim, Geehong Choi, Donghwi Lee, Namkyu Lee, Hyung Hee Cho

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Effective cooling technology is required to secure thermal stability in extreme heat generated systems such as integrated electronic devices and power generated systems. Pool boiling heat transfer is one of the powerful cooling mechanisms using phase change phenomena. Critical heat flux (CHF) and heat transfer coefficient (HTC) are main factors to evaluate the performance of boiling heat transfer. CHF is the limitation of boiling heat transfer before film boiling which occurs thermal failure. Surface wettability is an important surface characteristic of boiling heat transfer. A hydrophilic surface has higher CHF through effective working fluid supply to local hot spots. A hydrophobic surface promotes the onset of nucleate boiling (ONB) to enhance HTC. In this study, superbiphilic surfaces, which is combined with superhydrophillic and superhydrophobic, are applied on boiling experiments to maximize boiling performance. We conducted pool boiling heat transfer using DI water at a saturated temperature and recorded bubble dynamics using a high-speed camera with 2000 fps. As a result, superbiphilic patterned surfaces promote ONB and enhance both CHF and HTC. This study demonstrates the enhanced boiling performance using superbiphilic surfaces by effective nucleation and separation of liquid/vapor pathway. We expect that further enhancement of heat transfer could be achieved in future work using optimized patterned surfaces.

Keywords: boiling heat transfer, wettability, critical heat flux, heat transfer coefficient

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Authors: Jie Chen, Chris Cheng, Kai Zhang

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Polycrystalline diamond compact (PDC) cutters with a polycrystalline diamond (PCD) table supported by a cemented tungsten carbide substrate have been widely used for earth-drilling tools in the oil and gas industry. Both wear and impact resistances are key figure of merits of PDC cutters, and they are closely related to the microstructure of the PCD table. As oil and gas exploration enters deeper, harder, and more complex formations, plus increasing requirement of accelerated downhole drilling speed and drilling cost reduction, current PDC cutters face unprecedented challenges for maintaining a longer drilling life than ever. Excessive wear on uneven hard formations, spalling, chipping, and premature fracture due to impact loads are common failure modes of PDC cutters in the field. Tailoring microstructure of the PCD table is one of the effective approaches to improve the wear and impact resistances of PDC cutters, along with other factors such as cutter geometry and bit design. In this research, cross-sectional microstructure, fracture surface, wear surface, and elemental composition of PDC cutters were analyzed using scanning electron microscopy (SEM) with both backscattered electron and secondary electron detectors, and energy dispersive X-ray spectroscopy (EDS). The microstructure and elemental composition were further correlated with the wear and impact resistances of corresponding PDC cutters. Wear modes and impact toughening mechanisms of state-of-the-art PDCs were identified. Directions to further improve the wear and impact resistances of PDC cutters were proposed.

Keywords: fracture surface, microstructure, polycrystalline diamond, PDC, wear surface

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Authors: Zuxinsun, Samuel Eyley, Yongjian Guo, Reeta Salminen, Wim Thielemans

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Polypyrrole(PPy), as one of the most promising pseudocapacitor electrode materials, has attracted large research interest due to its low cost, high electrical conductivity and easy fabrication, limited capacitance, and cycling stability of PPy films hinder their practical applications. In this study, through adding different amounts of KCl into the pyrrole and CNC-COO⁻ system, three-dimensional, porous, and reticular PPy films were electropolymerized at last without the assistance of any template or substrate. Replacing KCl with NaCl, KBr, and NaClO4, the porous PPy films were still obtained rather than relatively dense PPy films which were deposited with pyrrole and CNC-COO⁻ or pyrrole and KCl. The nucleation and growth mechanisms of PPy films were studied in the deposited electrolyte with or without salts to illustrate the evolution of morphology from relatively dense to porous structure. The capacitance of PPy/CNC-COO⁻-Cl-(ClO4-)_0.5 films increased from 160.6 to 183.4 F g⁻¹ at 0.2 A g⁻¹. More importantly, at a high current density of 2.0 A g⁻¹ (20 mA cm⁻²), the PPy/CNC-COO⁻-Cl-(ClO4-)_0.5 films exhibited an excellent capacitance of 125.0 F g⁻¹ (1.19 F cm⁻²), increasing about 203.7 % over PPy/CNC-COO- films. 103.3 % of its initial capacitance was retained after 5000 cycles at 2 A g⁻¹ (20 mA cm⁻²) for the PPy/CNC-COO⁻-Cl-(ClO4-)_0.5 supercapacitor. The analyses reveal that the porous and reticular PPy/CNC-COO⁻-salts films open up more active reaction areas to store charges. The stiff and ribbonlike CNC-COO⁻ as the permanent dopants improve strength and stability of PPy/CNC-COO⁻-salts films. Our demonstration provides a simple and practical way to deposit PPy-based supercapacitors with high capacitance and cycling ability.

Keywords: polypyrrole, supercapacitors, cellulose nanocrystals, porous and reticular structure, inorganic salts

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Authors: Mian Adnan Kakakhel, NIshita Narwal, Majid Rasta, Shi Xiaotao

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The widespread use of nanoparticles means that they are significantly increasing in the aquatic ecosystem, where they are likely to pose threat to aquatic organism. In particular, the influence of nanoparticles exposure combined with varying water velocities on fish behavior remain poorly understood. Emerging evidences suggested a probable correlation between fish swimming behavior and gut bacterial dysbiosis. Therefore, the current study aimed to investigate the effects of nanomaterials in different water velocities on fish gut bacterial composition, which in results change in fish swimming behavior. The obtained findings showed that the contamination of nanoparticles was reduced as the velocity increased. However, the synergetic effects of nanoparticles and water velocity significantly (p < 0.05) decreased the bacterial composition, which plays a critical role in fish development, metabolism, digestion, enzymes production, and energy production such as Bacteroidetes and Firmicutes. This group of bacterial also support fish in swimming behavior by providing them a significant energy during movement. The obtained findings of this study suggested that the presence of nanoparticles in different water velocities have had a significant correlation with fish gut bacterial dysbiosis, as results the gut dysbiosis had been linked to the change in fish behavior. The study provides an important insight into the mechanisms by which the nanoparticles possibly affect the fish behavior.

Keywords: water velocities, fish behavior, gut bacteria, secondary metabolites, regulation

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Authors: Guliz Kolburan

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Juvenile delinquency studies has a special place and importance in criminality researches. Young adolescents, have not reached psychological, mental and physical maturity, and they cannot understand their roles and duties in society. In this case, if such an adolescent turns into a crime machine as a gang leader, he has the least responsibility of this result. All institutions, like family, school, community and the state as a whole have duties and responsibilities in this regard. While planning the studies about prevention of juvenile delinquency, all institutions related with the development of the children, should be involved in the center of the study. So that effective goals for prevention studies can be determined only in this way. Most of youth who commit homicide feel no attachment to anybody or society except for themselves. Children who committed homicide generally developed defense mechanisms about their guilt, sadness, fear and anger. For this reason, treatment of these children should be based on the awareness of these feelings and copying with them. In the movie, events making the youth realize his own feelings and responsibilities were studied from a theoretical perspective. In this study, some of the dialogs and the scenes in the movie were analyzed and the factors cause the young gang leader to be drawn to crime were evaluated in terms of the science of psychology. The aim of this study is to analyze the process of the youth to being drawn into criminal behavior in terms of social and emotional developmental phases in a theoretical perspective via the movie produced in 2005 (94. Min.). The method of this study is discourse analysis.

Keywords: crime, child, evaluation (development), psychology

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Authors: Farshad Amini, Kejun Wen

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The formation of reflective cracking of pavement overlays has confronted highway engineers for many years. Stress-relieving interlayers, such as paving fabrics, have been used in an attempt to reduce or delay reflective cracking. The effectiveness of paving fabrics in reducing reflection cracking is related to joint or crack movement in the underlying pavement, crack width, overlay thickness, subgrade conditions, climate, and traffic volume. The nonwoven geotextiles are installed between the old and new asphalt layers. Paving fabrics enhance performance through two mechanisms: stress relief and waterproofing. Several factors including proper installation, remedial work performed before overlay, overlay thickness, variability of pavement strength, existing pavement condition, base/subgrade support condition, and traffic volume affect the performance. The primary objective of this study was to conduct a long-term monitoring of the paving fabric interlayer systems to evaluate its effectiveness and performance. A comprehensive testing, monitoring, and analysis program were undertaken, where twelve 500-ft pavement sections of a four-lane highway were rehabilitated, and then monitored for seven years. A comparison between the performance of paving fabric treatment systems and control sections is reported. Lessons learned, and the various factors are discussed.

Keywords: monitoring, paving fabrics, performance, reflective cracking

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Authors: Lynne Soon-Chean Park

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Critical Realism (CR) has emerged as an alternative to both the positivist and constructivist perspectives that have long dominated social work research. By unpacking the epistemic weakness of two dogmatic perspectives, CR provides a useful philosophical approach that incorporates the ontological objectivist and subjectivist stance. The CR perspective suggests an alternative approach for social work researchers who have long been looking to engage in the complex interplay between perceived reality at the empirical level and the objective reality that lies behind the empirical event as a causal mechanism. However, despite the usefulness of CR in informing social work research, little practical guidance is available about how CR can inform methodological considerations in social work research studies. This presentation aims to provide a detailed description of CR-informed thematic analysis by drawing examples from a social work doctoral research of Korean migrants’ experiences and understanding of trust associated with their settlement experience in New Zealand. Because of its theoretical flexibility and accessibility as a qualitative analysis method, thematic analysis can be applied as a method that works both to search for the demi-regularities of the collected data and to identify the causal mechanisms that lay behind the empirical data. In so doing, this presentation seeks to provide a concrete and detailed exemplar for social work researchers wishing to employ CR in their qualitative thematic analysis process.

Keywords: critical Realism, data analysis, epistemology, research methodology, social work research, thematic analysis

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Authors: Hussain Hameed Mayuuf

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The study is an attempt to investigate the conceptual metonymies is used in political discourse about COVID-19. Thus, this study tries to analyze and investigate how the conceptual metonymies in Johnson's speech about coronavirus are constructed. This study aims at: Identifying how are metonymies relevant to understand the messages in Boris Johnson speeches and to find out how can conceptual blending theory help people to understand the messages in the political speech about COVID-19. Lastly, it tries to Point out the kinds of integration networks are common in political speech. The study is based on the hypotheses that conceptual blending theory is a powerful tool for investigating the intended messages in Johnson's speech and there are different processes of blending networks and conceptual mapping that enable the listeners to identify the messages in political speech. This study presents a qualitative and quantitative analysis of four speeches about COVID-19; they are said by Boris Johnson. The selected data have been tackled from the cognitive-semantic perspective by adopting Conceptual Blending Theory as a model for the analysis. It concludes that CBT is applicable to the analysis of metonymies in political discourse. Its mechanisms enable listeners to analyze and understand these speeches. Also the listener can identify and understand the hidden messages in Biden and Johnson's discourse about COVID-19 by using different conceptual networks. Finally, it is concluded that the double scope networks are the most common types of blending of metonymies in the political speech.

Keywords: cognitive, semantics, conceptual, metonymical, Covid-19

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Authors: Emmanuel Agunloye, Asterios Gavriilidis, Luca Mazzei

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Gold nanoparticles are commonly synthesized by reducing chloroauric acid with sodium citrate. This method, referred to as the citrate method, can produce spherical gold nanoparticles (NPs) in the size range 10-150 nm. Gold NPs of this size are useful in many applications. However, the NPs are usually polydisperse and irreproducible. A better understanding of the synthesis mechanisms is thus required. This work thoroughly investigated the only model that describes the synthesis. This model combines mass and population balance equations, describing the NPs synthesis through a sequence of chemical reactions. Chloroauric acid reacts with sodium citrate to form aurous chloride and dicarboxy acetone. The latter organizes aurous chloride in a nucleation step and concurrently degrades into acetone. The unconsumed precursor then grows the formed nuclei. However, depending on the pH, both the precursor and the reducing agent react differently thus affecting the synthesis. In this work, we investigated the model for different conditions of pH, temperature and initial reactant concentrations. To solve the model, we used Parsival, a commercial numerical code, whilst to test it, we considered various conditions studied experimentally by different researchers, for which results are available in the literature. The model poorly predicted the experimental data. We believe that this is because the model does not account for the acid-base properties of both chloroauric acid and sodium citrate.

Keywords: citrate method, gold nanoparticles, Parsival, population balance equations, Turkevich organizer theory

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Authors: Gheorghe Giurgiu, Manole Cojocaru, Mihnea Andrei Nicodin

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Background: Inflammation has the main role in the progression of endometriosis. The mechanisms by which endometriosis induces a chronic pain state remain poorly understood. Unfortunately, there is no known cure for endometriosis. But you can manage it with medication and at-home treatments. Some findings have highlighted the main role of inflammation in endometriosis by acting on proliferation, apoptosis, and angiogenesis. The introduction of new agents can be effective in improving the condition of patients; for example, plants are promising sources of bioactive natural components. Objectives: These natural compounds could be interesting strategies in therapy. While there is no absolute cure for this condition, some home remedies can relieve the pain and discomfort it brings. The purpose of this study is to summarize the potential action of Deniplant nutraceuticals in endometriosis by acting on inflammation. Materials and Methods: The primary symptoms of endometriosis are pelvic pain and infertility. The use of Deniplant nutraceuticals could be interesting in disease management for women. Results: Treating pain-related aspects of endometriosis would contribute to the improvement of mental health and daytime function. Because the microbiome can influence inflammation, new therapies can develop through its natural modulation. There are other options, including natural remedies, herbs like cinnamon twigs or licorice root, or supplements such as thiamine, magnesium, or omega-3 fatty acids. Conclusion: Deniplant nutraceuticals can downregulate inflammation in endometriosis. Nevertheless, the limited number of studies focusing on the different interactions of Deniplant nutraceuticals in endometriosis restricts its clear and immediate use in a therapeutic strategy.

Keywords: endometriosis, diet, Deniplant nutraceuticals, pain

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Authors: Mingjun Xu, Shouxiang Lu

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Understanding the interaction mechanism between the water droplet and pool fire has an important significance in engineering application of water sprinkle/spray/mist fire suppression. The micro impact process is unclear when the droplet impacts on the burning liquid surface at present. To deepen the understanding of the mechanisms of pool fire suppression with water spray/mist, dynamic processes of single water droplet impinging onto a hot heptane surface are visualized with the aid of a high-speed digital camera at 2000 fps. Each test is repeated 20 times. The water droplet diameter is around 1.98 mm, and the impact Weber number ranges from 30 to 695. The heptane is heated by a hot plate to mimic the burning condition, and the temperature varies from 30 to 90°C. The results show that three typical phenomena, including penetration, crater-jet and surface bubble, are observed, and the pool temperature has a significant influence on the critical condition for the appearance of each phenomenon. A global picture of different phenomena is built according to impact Weber number and pool temperature. In addition, the pool temperature and Weber number have important influences on the characteristic parameters including maximum crater depth, crown height and liquid column height. For a fixed Weber number, the liquid column height increases with pool temperature.

Keywords: droplet impact, fire suppression, hot surface, water spray

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Authors: Anwar Adem Shikur, Erhan Akkas

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Purpose: This study investigates the impact of Islamic microfinance services on poverty alleviation in Ethiopia. Methodology: Employing a binary logistic regression model, this research analyzes the relationship between poverty reduction and a range of variables—income, education, household size, age, and savings—among clients of Islamic microfinance services. Data was collected through a semi-structured questionnaire administered to a purposive sample and complemented by semi-structured interviews with senior officials from Islamic microfinance institutions. Findings: The study reveals that income, education, household size, and age of clients are primary determinants of poverty reduction within the context of Islamic microfinance services in Ethiopia. Practical Implications: The findings offer valuable insights for policymakers and government agencies seeking to enhance the livelihoods of Islamic microfinance clients and reduce poverty. Originality/Value: This research contributes to the existing literature by elucidating the specific mechanisms through which income, education, household size, and age influence poverty reduction among clients of Islamic microfinance services in Ethiopia. Furthermore, it provides a novel perspective on the role of Islamic microfinance in the country, including its challenges and opportunities. Social Implications: The study underscores the imperative for governments and institutions to prioritize financial inclusion as a means of addressing poverty and inequality across all socioeconomic strata.

Keywords: microfinance, binary logistic model, poverty reduction, Ethiopia.

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Authors: Federica Di Marcantonio, Antoine Leblois, Wolfgang Göbel, Hervè Kerdiles

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Weather-related shocks can threaten the ability of farmers to maintain their agricultural output and food security levels. Informal coping mechanisms (i.e. migration or community risk sharing) have always played a significant role in mitigating the negative effects of weather-related shocks in Ethiopia, but they have been found to be an incomplete strategy, particularly as a response to covariate shocks. Particularly, as an alternative to the traditional risk pooling products, an innovative form of insurance known as Index-based Insurance has received a lot of attention from researchers and international organizations, leading to an increased number of pilot initiatives in many countries. Despite the potential benefit of the product in protecting the livelihoods of farmers and pastoralists against climate shocks, to date there has been an unexpectedly low uptake. Using information from current pilot projects on index-based insurance in Ethiopia, this paper discusses the determinants of uptake that have so far undermined the scaling-up of the products, by focusing in particular on weather data availability, price affordability and willingness to pay. We found that, aside from data constraint issues, high price elasticity and low willingness to pay represent impediments to the development of the market. These results, bring us to rethink the role of index insurance as products for enhancing smallholders’ response to covariate shocks, and particularly for improving their food security.

Keywords: index-based insurance, willingness to pay, satellite information, Ethiopia

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Authors: Shubham Dwivedi, Raghavender Medishetti, Rita Rani, Aarti Sevilimedu, Pushkar Kulkarni, Yogeeswari Perumal

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Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder of early onset, characterized by impaired sociability, cognitive function and stereotypies. There is a significant urge to develop and establish new animal models with ASD-like characteristics for better understanding of underlying mechanisms. The aim of the present study was to develop a cost and time effective zebrafish model with quantifiable parameters to facilitate mechanistic studies as well as high-throughput screening of new molecules for autism. Zebrafish embryos were treated with valproic acid and a battery of behavioral tests (anxiety, inattentive behavior, irritability and social impairment) was performed on larvae at 7th day post fertilization, followed by study of molecular markers of autism. This model shows a significant behavioural impairment in valproic acid treated larvae in comparison to control which was again supported by alteration in few marker genes and proteins of autism. The model also shows a rescue of behavioural despair with positive control drugs. The model shows robust parameters to study behavior, molecular mechanism and drug screening approach in a single frame. Thus we postulate that our 7 days zebrafish larval model for autism can help in high throughput screening of new molecules on autism.

Keywords: autism, zebrafish, valproic acid, neurodevelopment, behavioral assay

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Authors: M. J. Pourvaghar, M. E. Bahram

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Obesity and overweight is one of the most common metabolic disorders in industrialized countries and in developing countries. One consequence of pathological obesity is cardiovascular disease and metabolic syndrome. Chemerin is an adipocyne that plays a role in the regulation of the adipocyte function and the metabolism of glucose in the liver and musculoskeletal system. Most likely, chemerin is involved in obesity-related disorders such as type 2 diabetes and cardiovascular disease. Aerobic exercises reduce the level of chemerin and cause macrophage penetration into fat cells and inflammatory factors. Several efforts have been made to clarify the cellular and molecular mechanisms of hypertrophy and muscular atrophy. Myostatin, a new member of the TGF-β family, is a transforming growth factor β that its expression negatively regulates the growth of the skeletal muscle; and the increase of this hormone has been observed in conditions of muscular atrophy. While in response to muscle overload, its levels decrease after the atrophy period, TGF-β is the most important cytokine in the development of skeletal muscle. Myostatin plays an important role in muscle control, and animal and human studies show a negative role of myostatin in the growth of skeletal muscle. Separation of myostatin from Golgi begins on the ninth day of the onset period and continues until birth at all times of muscle growth. Higher levels of myostatin are found in obese people. Resistance training for 10 weeks could reduce levels of plasma myostatin.

Keywords: chemerin, myostatin, obesity, physical activity

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Authors: Dina Mahmoud Hammouri

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The study investigates the Jordanian EFL learners’ pragmatic competence through their production of the speech acts of responding to requests, making suggestions, making threats and expressing farewells. The sample of the study consists of 130 Jordanian EFL learners and native speakers. 2600 responses were collected through a Discourse Completion Test (DCT). The findings of the study revealed that the tested students showed similarities and differences in performing the strategies of four speech acts. Differences in the students’ performances led to pragmatic failure instances. The pragmatic failure committed by students refers to a lack of linguistic competence (i.e., pragmalinguistic failure), sociocultural differences and pragmatic transfer (i.e., sociopragmatic failure). EFL learners employed many mechanisms to maintain their communicative competence; the analysis of the test on speech acts showed learners’ tendency towards using particular strategies, resorting to modify strategies and relating them to their grammatical competence, prefabrication, performing long forms, buffing and transfer. The results were also suggestive of the learners’ lack of pragmalinguistic and sociopragmatic knowledge. The implications of this study are for language teachers to teach interlanguage pragmatics explicitly in EFL contexts to draw learners’ attention to both pragmalinguistic and sociopragmatic features, pay more attention to these areas and allocate more time and practice to solve learners’ problems in these areas. The implication of this study is also for pedagogical material designers to provide sufficient and well-organized pragmatic input.

Keywords: pragmatic failure, Jordanian EFL learner, sociopragmatic competence, pragmalinguistic competence

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Authors: Neimenuo Kengurusie

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Human trafficking is considered a form of slavery in modern day era and a gross violation of human rights and one of the most organized crimes of the day transcending cultures, geography and time. Human trafficking is a highly complex phenomenon involving many actors like victims, survivors, their families, communities and third parties that recruit, transport and exploit the trafficked victims. It takes different forms such as child trafficking, trafficking for labour, trafficking for sexual exploitation, trafficking for organ transplantation etc. and affects virtually every corner of the world. This research draws on a variety of sources, including books, articles, journals, newspaper reports, human rights reports, online materials and interviews. In India, particularly the North East region, the issue of human trafficking has become a concern regionally, nationally and internationally. The focus of this paper is on the North Eastern part of India as it is a socially and economically backward region of the country which makes women and children susceptible to trafficking. Women and children from these regions are trafficked within and outside the state. Therefore, the paper seeks to explore the issue of human trafficking, especially trafficking of women and children in North East India, which receives insufficient attention in literature. The paper seeks to analyze and understand the trend and patterns of trafficking and the mechanisms that reinforces the process and perpetuates the phenomenon of trafficking considering the nature and scope of the problem. The paper also analyzes the anti-trafficking laws initiated by India and the North East states in particular for combating human trafficking in North East India.

Keywords: children, human trafficking, North East India, women

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Authors: Blanche Aguida, Marootpong Pooam, Nathalie Jourdan, Margaret Ahmad

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COVID-19-related morbidity is associated with exaggerated inflammation and cytokine production in the lungs, leading to acute respiratory failure. The cellular mechanisms underlying these so-called ‘cytokine storms’ are regulated through the Toll-like receptor 4 (TLR4) signaling pathway and by reactive oxygen species (ROS). Both light (photobiomodulation) and magnetic fields (e.g., pulsed electromagnetic field) stimulation are non-invasive therapies known to confer anti-inflammatory effects and regulate ROS signaling pathways. Here we show that daily exposure to two 10-minute intervals of moderate-intensity infra-red light significantly lowered the inflammatory response induced via the TLR4 receptor signaling pathway in human cell cultures. Anti-inflammatory effects were likewise achieved by electromagnetic field exposure of cells to daily 10-minute intervals of either pulsed electromagnetic fields (PEMF) or to low-level static magnetic fields. Because current illumination and electromagnetic field therapies have no known side effects and are already approved for some medical uses, we have here developed protocols for verification in clinical trials of COVID 19 infection. These treatments are affordable, simple to implement, and may help to resolve the acute respiratory distress of COVID 19 patients both in the home and in the hospital.

Keywords: COVID 19, electromagnetic fields therapy, inflammation, photobiomodulation therapy

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Authors: Jianfang Wang, Xianzhe Chen, Zhuoliang Liu, Cheng-An Tao, Yujiao Li

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Organophosphorus (OPs) pesticide used as insecticides are widely used in agricultural pest control, household and storage deworming. The detection of pesticides needs more simple and efficient methods. One of the best ways is to make electrochemical biosensors. In this paper, an electrochemical enzyme biosensor based on acetylcholine esterase (AChE) was constructed, and its sensing properties and sensing mechanisms were studied. Reduced graphene oxide-polydopamine complexes (RGO-PDA), gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) were prepared firstly and composited with AChE and chitosan (CS), then fixed on the glassy carbon electrode (GCE) surface to construct the biosensor GCE/RGO-PDA-AuNPs-AgNPs-AChE-CS by one-pot method. The results show that graphene oxide (GO) can be reduced by dopamine (DA) and dispersed well in RGO-PDA complexes. And the composites have a synergistic catalysis effect and can improve the surface resistance of GCE. The biosensor selectively can detect acetylcholine (ACh) and OPs pesticide with good linear range and high sensitivity. The performance of the biosensor is affected by the ratio and adding ways of AChE and the adding of AuNPs and AChE. And the biosensor can achieve a detection limit of 2.4 ng/L for methyl parathion and a wide linear detection range of 0.02 ng/L ~ 80 ng/L, and has excellent stability, good anti-interference ability, and excellent preservation performance, indicating that the sensor has practical value.

Keywords: acetylcholine esterase, electrochemical biosensor, nanoparticles, organophosphates, reduced graphene oxide

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Authors: Chien-Kuo Chang, You-Syuan Wu, Min-Chiu Wu, Bharath-Kumar Boyanapalli

Abstract:

The electrical treeing mechanism in epoxy resin insulation is a critical area of study concerning the degradation of high-voltage electrical equipment. In this study, we conducted pressure-induced degradation experiments on epoxy resin specimens using a needle-plane electrode structure to simulate electrical treeing. The specimens featured two different defect spacings, allowing for detailed observation facilitated by time-lapse photography. Our investigation revealed four distinct stages of insulation degradation: initial dark tree growth, filamentary tree growth, reverse tree growth, and eventual insulation breakdown. The initial dark treeing stage, though shortest in duration, exhibited a thicker main branch and shorter branching, ceasing upon the appearance of filamentary treeing. Filamentary treeing manifested in two forms: dark filamentary treeing during the resin's glassy state, characterized by branching structures, and fuzzy filamentary treeing during the rubbery state, resembling white feathers. The channels formed by filamentary treeing were observed to be as narrow as a few micrometers and continued to grow until the end of the experiment. Additionally, the transition to reverse treeing occurred when filamentary treeing reached the ground electrode, with the earliest manifestation being growth from the ground electrode towards the high-voltage end.

Keywords: epoxy resin insulation, high-voltage equipment, electrical treeing mechanism

Procedia PDF Downloads 75

Authors: L. Al Ahmad, C. Latrille, D. Hainos, D. Blanc, M. Clausse

Abstract:

A two-dimensional finite volume axisymmetric model is developed to predict the simultaneous heat and mass transfers during the drying of industrial sludge. The simulations were run using COMSOL-Multiphysics 3.5a. The input parameters of the numerical model were acquired from a preliminary experimental work. Results permit to establish correlations describing the evolution of the various parameters as a function of the drying temperature and the sludge water content. The selection and coupling of the equation are validated based on the drying kinetics acquired experimentally at a temperature range of 45-65 °C and absolute pressure range of 200-1000 mbar. The model, incorporating the heat and mass transfer mechanisms at different operating conditions, shows simulated values of temperature and water content. Simulated results are found concordant with the experimental values, only at the first and last drying stages where sludge shrinkage is insignificant. Simulated and experimental results show that sludge drying is favored at high temperatures and low pressure. As experimentally observed, the drying time is reduced by 68% for drying at 65 °C compared to 45 °C under 1 atm. At 65 °C, a 200-mbar absolute pressure vacuum leads to an additional reduction in drying time estimated by 61%. However, the drying rate is underestimated in the intermediate stage. This rate underestimation could be improved in the model by considering the shrinkage phenomena that occurs during sludge drying.

Keywords: industrial sludge drying, heat transfer, mass transfer, mathematical modelling

Procedia PDF Downloads 134

Authors: Ben Mansour Mouin, Elloumi Abdelkarim

Abstract:

We will discuss the problem of routing a fleet of different vehicles from a central depot to different types of infrastructure-defaults with dynamic maintenance requests, modified time windows, and control of default maintained. For this reason, we propose a modified metaheuristicto to solve our mathematical model. SVRDP-CMTW is a variant VRP of an optimal vehicle plan that facilitates the maintenance task of different types of infrastructure-defaults. This task will be monitored after the maintenance, based on its priorities, the degree of danger associated with each default, and the neighborhood at the black-spots. We will present, in this paper, a multidimensional genetic algorithm “MGA” by detailing its characteristics, proposed mechanisms, and roles in our work. The coding of this algorithm represents the necessary parameters that characterize each infrastructure-default with the objective of minimizing a combination of cost, distance and maintenance times while satisfying the priority levels of the most urgent defaults. The developed algorithm will allow the dynamic integration of newly detected defaults at the execution time. This result will be displayed in our programmed interactive system at the routing time. This multidimensional genetic algorithm replaces N genetic algorithm to solve P different type problems of infrastructure defaults (instead of N algorithm for P problem we can solve in one multidimensional algorithm simultaneously who can solve all these problemsatonce).

Keywords: mathematical model, VRP, multidimensional genetic algorithm, metaheuristics

Procedia PDF Downloads 196

Authors: A. M. Tiara, Sudipto Chakraborty, S. K. Pal

Abstract:

Impinging jets and their different configurations are important from the viewpoint of the fluid flow characteristics and their influence on heat transfer from metal surfaces due to their complex flow characteristics. Such flow characteristics results in highly variable heat transfer from the surface, resulting in varying cooling rates which affects the mechanical properties including hardness and strength. The overall objective of the current research is to conduct a fundamental investigation of the heat transfer mechanisms for an impinging coolant jet. Numerical simulation of the cooling process gives a detailed analysis of the different parameters involved even though employing Computational Fluid Dynamics (CFD) to simulate the real time process, being a relatively new research area, poses many challenges. The heat transfer mechanism in the current research is actuated by jet cooling. The computational tool used in the ongoing research for simulation of the cooling process is ANSYS Workbench software. The temperature and heat flux distribution along the steel strip with the effect of various flow parameters on the heat transfer rate can be observed in addition to determination of the jet impingement patterns, which is the major aim of the present analysis. Modelling both jet and air atomized cooling techniques using CFD methodology and validating with those obtained experimentally- including trial and error with different models and comparison of cooling rates from both the techniques have been included in this work. Finally some concluding remarks are made that identify some gaps in the available literature that have influenced the path of the current investigation.

Keywords: CFD, heat transfer, impinging jets, numerical simulation

Procedia PDF Downloads 235

Authors: Mennatallah M. Hussein, Olivier de Weck

Abstract:

The advancement of space exploration demands a robust space launch services program capable of reliably propelling payloads into orbit. Despite rigorous testing and quality assurance, launch failures still occur, leading to significant financial losses and jeopardizing mission objectives. Traditional failure prediction methods often lack the sophistication to account for multi-mode failure scenarios, as well as the predictive capability in complex dynamic systems. Traditional approaches also rely on expert judgment, leading to variability in risk prioritization and mitigation strategies. Hence, there is a pressing need for robust approaches that enhance launch vehicle reliability from lift-off until it reaches its parking orbit through comprehensive simulation techniques. In this study, the developed model proposes a multi-mode launch vehicle simulation framework for predicting failure scenarios when incorporating new technologies, such as new propulsion systems or advanced staging separation mechanisms in the launch system. To this end, the model combined a 6-DOF system dynamics with comprehensive data analysis to simulate multiple failure modes impacting launch performance. The simulator utilizes high-fidelity physics-based simulations to capture the complex interactions between different subsystems and environmental conditions.

Keywords: launch vehicle, failure prediction, propulsion anomalies, rocket launch simulation, rocket dynamics

Procedia PDF Downloads 31

Authors: Magdalena Blachnio, Viktor Bogatyrov, Mariia Galaburda, Anna Derylo-Marczewska

Abstract:

Agricultural waste materials from traditional oil mill and after extraction of natural raw materials in supercritical conditions were used for the preparation of carbon nanomaterials (activated carbons) by two various methods. Chemical activation using acetic acid and physical activation with a gaseous agent (carbon dioxide) were chosen as mild and environmentally friendly ones. The effect of influential factors: type of raw material, temperature and activation agent on the porous structure characteristics of the materials was discussed by using N₂ adsorption/desorption isotherms at 77 K. Furthermore scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were employed to examine the physicochemical properties of the obtained sorbents. Selection of a raw material and an optimization of the conditions of the synthesis process, allowed to obtain the cheap sorbents with a targeted distribution of pores enabling effective adsorption of the model organic pollutants carried out in the multicomponent systems. Adsorption behavior (capacity and rate) of the chosen activated carbons was estimated by utilizing Crystal violet (CV), 4-chlorophenoxyacetic acid (4-CPA), 2.4-dichlorophenoxyacetic acid (2.4-D) as the adsorbates. Both rate and adsorption capacity of the organics on the sorbents evidenced that the activated carbons could be effectively used in sewage treatment plants. The mechanisms of organics adsorption were studied and correlated with activated carbons properties.

Keywords: activated carbon, adsorption equilibrium, adsorption kinetics, organics adsorption

Procedia PDF Downloads 177