Search results for: focal loss

Authors: Mohammad Ebrahim Kianifar, Ehsan Ahmadi

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Reinforced concrete structures experience local defects such as cracks over their lifetime under various environmental loadings. Consequently, they are repaired by mortars to avoid detrimental effects such as corrosion of reinforcement, which in long-term may lead to strength loss of a member or collapse of structures. However, repaired structures may need multiple repairs due to changes in load distribution, and thus, lack of compatibility between mortar and substrate concrete. On the other hand, waste tire rubber alkali-activated (WTRAA)-based materials have very high potential to be used as repair mortars because of their ductility and flexibility, which may delay the failure of repair mortar and thus, provide sufficient compatibility. Hence, this work presents a pioneering study on suitability of WTRAA-based materials as mortars for the repair of concrete structures through an experimental program. To this end, WTRAA mortars with 15% aggregate replacement, alkali-activated (AA) mortars, and ordinary mortars are made to repair a number of concrete beams. The WTRAA mortars are composed of slag as base material, sodium hydroxide as an alkaline activator, and different gradations of waste tire rubber (fine and coarse gradations). Flexural tests are conducted on the concrete beams repaired by the ordinary, AA, and WTRAA mortars. It is found that, despite having lower compressive strength and modulus of elasticity, the WTRAA and AA mortars increase the flexural strength of the repaired beams, give compatible failures, and provide sufficient mortar-concrete interface bondings. The ordinary mortars, however, show incompatible failure modes. This study demonstrates the promising application of WTRAA mortars in the practical repairs of concrete structures.

Keywords: alkali-activated mortars, concrete repair, mortar compatibility, flexural strength, waste tire rubber

Procedia PDF Downloads 155

Authors: Solange Adechian, Michèle Balage, Didier Remond, Carole Migné, Annie Quignard-Boulangé, Agnès Marset-Baglieri, Sylvie Rousset, Yves Boirie, Claire Gaudichon, Dominique Dardevet, Laurent Mosoni

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Studies have shown that timing of protein intake, leucine content, and speed of digestion significantly affect postprandial protein utilization. Our aim was to determine if one can spare lean body mass during energy restriction by varying the quality and the timing of protein intake. Obese volunteers followed a 6-wk restricted energy diet. Four groups were compared: casein pulse, casein spread, milk-soluble protein (MSP, = whey) pulse, and MSP spread (n = 10-11 per group). In casein groups, caseins were the only protein source; it was MSP in MSP groups. Proteins were distributed in four meals per day in the proportion 8:80:4:8% in the pulse groups; it was 25:25:25:25% in the spread groups. We measured weight, body composition, nitrogen balance, 3-methylhistidine excretion, perception of hunger, plasma parameters, adipose tissue metabolism, and whole body protein metabolism. Volunteers lost 7.5 ± 0.4 kg of weight, 5.1 ± 0.2 kg of fat, and 2.2 ± 0.2 kg of lean mass, with no difference between groups. In adipose tissue, cell size and mRNA expression of various genes were reduced with no difference between groups. Hunger perception was also never different between groups. In the last week, due to a higher inhibition of protein degradation and despite a lower stimulation of protein synthesis, postprandial balance between whole body protein synthesis and degradation was better with caseins than with MSP. It seems likely that the positive effect of caseins on protein balance occurred only at the end of the experiment.

Keywords: lean body mass, fat mass, casein, whey, protein metabolism

Procedia PDF Downloads 72

Authors: Luanna B. Prevost, Kelli Carter, Margaurete Romero, Kirsti Martinez

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Writing is an essential scientific practice, yet, in several countries, the increasing university science class-size limits the use of written assessments. Written assessments allow students to demonstrate their learning in their own words and permit the faculty to evaluate students’ understanding. However, the time and resources required to grade written assessments prohibit their use in large-enrollment science courses. This study examined the use of machine learning algorithms to automatically analyze student writing and provide timely feedback to the faculty about students' writing in biology. Written responses to questions about matter and energy transformation were collected from large-enrollment undergraduate introductory biology classrooms. Responses were analyzed using the LightSide text mining and classification software. Cohen’s Kappa was used to measure agreement between the LightSide models and human raters. Predictive models achieved agreement with human coding of 0.7 Cohen’s Kappa or greater. Models captured that when writing about matter-energy transformation at the ecosystem level, students focused on primarily on the concepts of heat loss, recycling of matter, and conservation of matter and energy. Models were also produced to capture writing about processes such as decomposition and biochemical cycling. The models created in this study can be used to provide automatic feedback about students understanding of these concepts to biology faculty who desire to use formative written assessments in larger enrollment biology classes, but do not have the time or personnel for manual grading.

Keywords: machine learning, written assessment, biology education, text mining

Procedia PDF Downloads 281

Authors: Sara A. Al-Jaberi, Salma Ben-Salem, Meriam Messedi, Fatma Ayadi, Lihadh Al-Gazali, Bassam R. Ali

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Background: The chemokine receptor components play crucial roles in the immune system and some of them serve as co-receptors for the HIV virus. Several studies have documented those variants in chemokine receptors are correlated with susceptibility and resistance to infection with HIV virus. For example, mutations in the chemokine receptor 5 gene (CCR5) resulting in loss-of-function (such as the homozygous CCR5Δ32) confer high degree of resistance to HIV infection. Heterozygotes for these variants exhibit slow progression to AIDS. The prevalence of CCR5 polymorphisms varies among ethnic and geographical groups. For example, the CCR5 Δ32 variant is present in 10–15% of north Europeans but is rarely encountered among Africans. This study aims to identify the prevalence of some CCR5 variants in two geographically distant Arab populations (namely Emiratis and Tunisians). Methodology: The prevalence of CCR5 gene variants including CCR5Δ32, FS299, C101X, A29S and C178R has been determined using PCR and direct DNA sequencing. A total of 403 unrelated healthy individuals (253 Emiratis and 150 Tunisians) were genotyped for the CCR5Δ32 variant using PCR amplification and gel electrophoresis. In addition, 200 Emiratis have been screened for other SNPs using Sanger DNA sequencing. Results: Among Emiratis, the allele frequency of the CCR5Δ32 variant has been found to be 0.002. In addition, two variants L55Q and A159 were found at a frequency of 0.002.Moreover, the prevalence of the CCR5Δ32 variant in Tunisians was estimated to be 0.013 which is relatively higher than its frequency in Emiratis but lower than Europeans. Conclusion: We conclude that the allele frequency of the most critical CCR5 polymorphism (Δ32) is extremely low among Emiratis compared to other Arabs and North Europeans. In addition, very low allele frequencies of other CCR5 polymorphisms have been detected among Emiratis.

Keywords: chemokine receptors, CCR5Δ32, CCR5 polymorphisms, Emiratis, Arab populations

Procedia PDF Downloads 378

Authors: Hyun Lim, Dong Sook Min, Han Eul Yun, Kil Tae Kim, Ya Nan Sun, Young Ho Kim, Hyun Pyo Kim

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Matrix metalloproteinase (MMP)-13 has an important role for degrading cartilage materials under inflammatory conditions such as arthritis. Since the 70% ethanol extract of Acanthopanax koreanum inhibited MMP-13 expression in IL-1β-treated human chondrocyte cell line, SW1353, two major constituents including acanthoic acid and impressic acid were initially isolated from the same plant materials and their MMP-13 down-regulating capacity was examined. In IL-1β-treated SW1353 cells, acanthoic acid and impressic acid significantly and concentration-dependently inhibited MMP-13 expression at 10 – 100 μM and 0.5 – 10 μM, respectively. The potent one, impressic acid, was found to inhibit MMP-13 expression by blocking the phosphorylation of signal transducer and activator of transcription-1/-2 (STAT-1/-2) and activation of c-Jun and c-Fos among cellular signaling pathway involved, but did not affect the activation of mitogen-activated protein kinases (MAPKs) and nuclear transcription factor-κB (NF-κB). Further, impressic acid was also found to inhibit the expression of MMP-13 mRNA (47.7% inhibition at 10 μM), the glycosaminoglycan release (42.2% reduction at 10 μM) and proteoglycan loss in IL-1-treated rabbit cartilage explants culture. For a further study, 21 impressic acid derivatives were isolated from the same plant materials and their suppressive activities against MMP-13 expression were examined. Among the derivatives, 3α-hydroxy-lup-20(29)-en-23-oxo,28-oic acid, (20R)-3α-hydroxy-29-dimethoxylupan-23,28-dioic acid, acankoreoside F and acantrifoside A clearly down-regulated MMP-13 expression, but impressic acid being most potent. All these results suggest that impressic acid, 3α-hydroxy-lup-20(29)-en-23-oxo,28-oic acid, (20R)-3α-hydroxy-29-dimethoxylupan-23,28-dioic acid, acankoreoside F, acantrifoside A and A. koreanum may have a potential for therapeutic agents to prevent cartilage degradation possibly by inhibiting matrix protein degradation.

Keywords: acanthoic acid, Acanthopanax koreanum, cartilage, impressic acid, matrix metalloproteinase

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Authors: P. van Tonder, U. Bagdadi, B. M. D. Lario, Z. Masina, T. R. Motshwari

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This paper analyses how concrete reinforcing steel bars corrode and how it can be minimised through the use of various protection methods against corrosion, such as metal-based paint, alloying, cathodic protection and electroplating. Samples of carbon steel bars were protected, using these four methods. Tests performed on the samples included durability, electrical resistivity and bond strength. Durability results indicated relatively low corrosion rates for alloying, cathodic protection, electroplating and metal-based paint. The resistivity results indicate all samples experienced a downward trend, despite erratic fluctuations in the data, indicating an inverse relationship between electrical resistivity and corrosion rate. The results indicated lowered bond strengths when the reinforced concrete was cured in seawater compared to being cured in normal water. It also showed that higher design compressive strengths lead to higher bond strengths which can be used to compensate for the loss of bond strength due to corrosion in a real-world application. In terms of implications, all protection methods have the potential to be effective at resisting corrosion in real-world applications, especially the alloying, cathodic protection and electroplating methods. The metal-based paint underperformed by comparison, most likely due to the nature of paint in general which can fade and chip away, revealing the steel samples and exposing them to corrosion. For alloying, stainless steel is the suggested material of choice, where Y-bars are highly recommended as smooth bars have a much-lowered bond strength. Cathodic protection performed the best of all in protecting the sample from corrosion, however, its real-world application would require significant evaluation into the feasibility of such a method.

Keywords: protection methods, corrosion, concrete, reinforcing steel bars

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Authors: Yi-Guang Li, Suresh Sampath

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Gas turbine performance degrades over time, and the degradation is greatly affected by environmental, ambient, and operating conditions. The engines may degrade slowly under favorable conditions and result in a waste of engine life if a scheduled maintenance scheme is followed. They may also degrade fast and fail before a scheduled overhaul if the conditions are unfavorable, resulting in serious secondary damage, loss of engine availability, and increased maintenance costs. To overcome these problems, gas turbine owners are gradually moving from scheduled maintenance to condition-based maintenance, where condition monitoring is one of the key supporting technologies. This paper presents an integrated adaptive GPA diagnostics and performance monitoring system developed at Cranfield University for gas turbine gas path condition monitoring. It has the capability to predict the performance degradation of major gas path components of gas turbine engines, such as compressors, combustors, and turbines, using gas path measurement data. It is also able to predict engine key performance parameters for condition monitoring, such as turbine entry temperature that cannot be directly measured. The developed technology has been implemented into digital twin computer Software, Pythia, to support the condition monitoring of gas turbine engines. The capabilities of the integrated GPA condition monitoring system are demonstrated in three test cases using a model gas turbine engine similar to the GE aero-derivative LM2500 engine widely used in power generation and marine propulsion. It shows that when the compressor of the model engine degrades, the Adaptive GPA is able to predict the degradation and the changing engine performance accurately using gas path measurements. Such a presented technology and software are generic, can be applied to different types of gas turbine engines, and provide crucial engine health and performance parameters to support condition monitoring and condition-based maintenance.

Keywords: gas turbine, adaptive GPA, performance, diagnostics, condition monitoring

Procedia PDF Downloads 88

Authors: Hsiao-Tien Pao, Yi-Ying Li, Hsin-Chia Fu

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This paper addressed the impacts of energy consumption, economic growth, financial development, and population size on environmental degradation using grey relational analysis (GRA) for China, where foreign direct investment (FDI) inflows is the proxy variable for financial development. The more recent historical data during the period 2004–2011 are used, because the use of very old data for data analysis may not be suitable for rapidly developing countries. The results of the GRA indicate that the linkage effects of energy consumption–emissions and GDP–emissions are ranked first and second, respectively. These reveal that energy consumption and economic growth are strongly correlated with emissions. Higher economic growth requires more energy consumption and increasing environmental pollution. Likewise, more efficient energy use needs a higher level of economic development. Therefore, policies to improve energy efficiency and create a low-carbon economy can reduce emissions without hurting economic growth. The finding of FDI–emissions linkage is ranked third. This indicates that China do not apply weak environmental regulations to attract inward FDI. Furthermore, China’s government in attracting inward FDI should strengthen environmental policy. The finding of population–emissions linkage effect is ranked fourth, implying that population size does not directly affect CO₂ emissions, even though China has the world’s largest population, and Chinese people are very economical use of energy-related products. Overall, the energy conservation, improving efficiency, managing demand, and financial development, which aim at curtailing waste of energy, reducing both energy consumption and emissions, and without loss of the country’s competitiveness, can be adopted for developing economies. The GRA is one of the best way to use a lower data to build a dynamic analysis model.

Keywords: China, CO₂ emissions, foreign direct investment, grey relational analysis

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Authors: Abolghasem Yousefi-Babadi, Ali Bozorgi-Amiri, Aida Kazempour, Reza Tavakkoli-Moghaddam, Maryam Irani

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All over the world, natural disasters (e.g., earthquakes, floods, volcanoes and hurricanes) causes a lot of deaths. Earthquakes are introduced as catastrophic events, which is accident by unusual phenomena leading to much loss around the world. Such could be replaced by disasters or any other synonyms strongly demand great long-term help and relief, which can be hard to be managed. Supplies and facilities are very important challenges after any earthquake which should be prepared for the disaster regions to satisfy the people's demands who are suffering from earthquake. This paper proposed disaster response facility allocation problem for disaster relief operations as a mathematical programming model. Not only damaged people in the earthquake victims, need the consumable commodities (e.g., food and water), but also they need non-consumable commodities (e.g., clothes) to protect themselves. Therefore, it is concluded that paying attention to disaster points and people's demands are very necessary. To deal with this objective, both commodities including consumable and need non-consumable commodities are considered in the presented model. This paper presented the multi-objective multi-period mathematical programming model regarding the minimizing the average of the weighted response times and minimizing the total operational cost and penalty costs of unmet demand and unused commodities simultaneously. Furthermore, a Chebycheff multi-objective solution procedure as a powerful solution algorithm is applied to solve the proposed model. Finally, to illustrate the model applicability, a case study of the Tehran earthquake is studied, also to show model validation a sensitivity analysis is carried out.

Keywords: facility location, multi-objective model, disaster response, commodity

Procedia PDF Downloads 257

Authors: Asad Iqbal, Feixiang Zan, Xiaoming Liu, Guang-Hao Chen

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Water, food, and energy nexus is a vital subject to achieve sustainable development goals worldwide. Wastewater (WW) and food waste (FW) from municipal sources are primary contributors to their respective wastage sum from a country. Along with the loss of these invaluable natural resources, their treatment systems also consume a lot of abiotic energy and resources input with a perceptible contribution to global warming. Hence, the global paradigm has evolved from simple pollution mitigation to a resource recovery system (RRS). In this study, the prospects of six alternative FW treatment scenarios are quantitatively evaluated for Hong Kong in terms of energy use and greenhouse emissions (GHEs) potential, using life cycle assessment (LCA). Considered scenarios included: aerobic composting, anaerobic digestion (AD), combine AD and composting (ADC), co-disposal, and treatment with wastewater (CoD-WW), incineration, and conventional landfilling as base-case. Results revealed that in terms of GHEs saving, all-new scenarios performed significantly better than conventional landfilling, with ADC scenario as best-case and incineration, AD alone, CoD-WW ranked as second, third, and fourth best respectively. Whereas, composting was the worst-case scenario in terms of energy balance, while incineration ranked best and AD alone, ADC, and CoD-WW ranked as second, third, and fourth best, respectively. However, these results are highly sensitive to boundary settings, e.g., the inclusion of the impact of biogenic carbon emissions and waste collection and transportation, and several other influential parameters. The study provides valuable insights and policy guidelines for the decision-makers locally and a generic modelling template for environmental impact assessment.

Keywords: food waste, resource recovery, greenhouse emissions, energy balance

Procedia PDF Downloads 107

Authors: Kamilya Khamitova

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This study analyzes the overarching theme of obsession as portrayed through the two protagonists, Humbert Humbert and Kemal, in Vladimir Nabokov's Lolita and Orhan Pamuk's The Museum of Innocence through the lens of Freudian psychoanalytical theory of “transference.” Their obsessions are channeled into various forms of artistic expression following the loss of their beloved Lolita and Füsun. Employing psychoanalytical literary criticism, firmly grounded in the classical era of psychoanalysis, as pioneered by Sigmund Freud, this research explores the characters' psyches, revealing the concealed desires, conflicts, and symbolic manifestations within their relentless obsessions. The aim of this study is to unravel the psychological complexities of obsession, shedding light on the motivations and behaviors of Humbert and Kemal within the context of their respective narratives. Methodologically, this research employs close textual analysis of the novels, dissecting the protagonists' thoughts, actions, and artistic expressions. Through the lens of Freud's fundamental concept of “transference,” this analysis uncovers the protagonists' mechanisms of projecting their desires onto unattainable objects of desire—Lolita and Füsun. Humbert's pursuit of Lolita mirrors his unresolved emotional traumas and attempts to recapture the lost object of his childhood. In contrast, Kemal's fixation on Füsun is a desperate desire to fill an existential void, address a sense of inadequacy, and construct a semblance of immortality through the meticulous preservation of his memories with her. By adopting a psychoanalytic lens, this research provides a richer understanding of the characters, themes, and symbolism inherent in their artistic expressions of devotion.

Keywords: artistic expression, psychoanalysis of obsession, Sigmund Freud, transference

Procedia PDF Downloads 160

Authors: Dawid Stawski, Silviya Halacheva, Dorota Zielińska

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The surface properties of many materials can be readily and predictably modified by the controlled deposition of thin layers containing appropriate functional groups and this research area is now a subject of widespread interest. The layer-by-layer (lbl) method involves depositing oppositely charged layers of polyelectrolytes onto the substrate material which are stabilized due to strong electrostatic forces between adjacent layers. This type of modification affords products that combine the properties of the original material with the superficial parameters of the new external layers. Through an appropriate selection of the deposited layers, the surface properties can be precisely controlled and readily adjusted in order to meet the requirements of the intended application. In the presented paper a variety of anionic (poly(acrylic acid)) and cationic (linear poly(ethylene imine), polymers were successfully deposited onto the polypropylene nonwoven using the lbl technique. The chemical structure of the surface before and after modification was confirmed by reflectance FTIR spectroscopy, volumetric analysis and selective dyeing tests. As a direct result of this work, new materials with greatly improved properties have been produced. For example, following a modification process significant changes in the electrostatic activity of a range of novel nanocomposite materials were observed. The deposition of polyelectrolyte nanolayers was found to strongly accelerate the loss of electrostatically generated charges and to increase considerably the thermal resistance properties of the modified fabric (the difference in T50% is over 20°C). From our results, a clear relationship between the type of polyelectrolyte layer deposited onto the flat fabric surface and the properties of the modified fabric was identified.

Keywords: layer-by-layer technique, polypropylene nonwoven, surface modification, surface properties

Procedia PDF Downloads 435

Authors: Malay K. Pramanik

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Climate change is continuously affecting the ecosystem, species distribution as well as global biodiversity. The assessment of the species potential distribution and the spatial changes under various climate change scenarios is a significant step towards the conservation and mitigation of habitat shifts, and species' loss and vulnerability. In this context, the present study aimed to predict the influence of current and future climate on an ecologically vulnerable medicinal species, Garcinia gummi-gutta, of the southern Western Ghats using Maximum Entropy (MaxEnt) modeling. The future projections were made for the period of 2050 and 2070 with RCP (Representative Concentration Pathways) scenario of 4.5 and 8.5 using 84 species occurrence data, and climatic variables from three different models of Intergovernmental Panel for Climate Change (IPCC) fifth assessment. Climatic variables contributions were assessed using jackknife test and AOC value 0.888 indicates the model perform with high accuracy. The major influencing variables will be annual precipitation, precipitation of coldest quarter, precipitation seasonality, and precipitation of driest quarter. The model result shows that the current high potential distribution of the species is around 1.90% of the study area, 7.78% is good potential; about 90.32% is moderate to very low potential for species suitability. Finally, the results of all model represented that there will be a drastic decline in the suitable habitat distribution by 2050 and 2070 for all the RCP scenarios. The study signifies that MaxEnt model might be an efficient tool for ecosystem management, biodiversity protection, and species re-habitation planning under climate change.

Keywords: Garcinia gummi gutta, maximum entropy modeling, medicinal plants, climate change, western ghats, MaxEnt

Procedia PDF Downloads 392

Authors: Saida Haider, Syeda Madiha

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Parkinson’s disease (PD) is a common neurological disorder characterized by motor deficits and loss of dopaminergic neurons. Oxidative stress is said to play a pivotal role in the pathophysiology of the disease. In the present study, PD was induced by injection of rotenone (1.5 mg/kg/day, s.c.) for eight days. Pistachio (800 mg/kg/day, p.o.) was given for two weeks. At the end of treatment brains were dissected out and striatum was isolated for biochemical and neurochemical analysis. Morris water maze (MWM) test and novel object recognition (NOR) task was used to test the memory function while motor behavior was determined by open field test (OFT), Kondziela inverted screen test (KIST), pole test (PT), beam walking test (BWT), inclined plane test (IPT) and footprint (FP) test. Several dietary components have been evaluated as potential therapeutic compounds in many neurodegenerative diseases. Increasing evidence shows that nuts have protective effects against various diseases by improving the oxidative status and reducing lipid peroxidation. Pistachio is the only nut that contains anthocyanin, a potent antioxidant having neuroprotective properties. Results showed that pistachio supplementation significantly restored the rotenone-induced motor deficits and improved the memory performance. Moreover, rats treated with pistachio also exhibited enhanced oxidative status and increased dopamine (DA) and 5-hydroxytryptamine (5-HT) concentration in striatum. In conclusion, to our best knowledge, we have for the first time shown that pistachio nut possesses neuroprotective effects against rotenone-induced motor and cognitive deficits. These beneficial effects of pistachio may be attributed to its high content of natural antioxidant and phenolic compounds. Hence, consumption of pistachio regularly as part of a daily diet can be beneficial in the prevention and treatment of PD.

Keywords: rotenone, pistachio, oxidative stress, Parkinson’s disease

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Authors: Maryam Nazari, Atefeh Ghanbari, Saghar Noorinia

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Obesity, as an abnormal or excessive accumulation of fat, is caused by genetic, behavioral and environmental factors. Recently, obesity surgeries, such as bariatric surgery, as the last measure to control obesity, have attracted experts and society, especially women, attention, so knowing the possible complications of this major surgery and their control in reproductive age is of particular importance due to its effects on pregnancy outcomes. Bariatric surgery reduces the risk of diabetes and high blood pressure associated with pregnancy, premature birth, macrosomia, stillbirth and dumping syndrome. Although in the first months after surgery, nausea and vomiting caused by changes in intra-abdominal pressure are associated with an increased risk of malabsorption of micronutrients such as folic acid, iron, vitamin B1, D, calcium, selenium and phosphorus and finally, fetal growth disorder. Moreover, serum levels of micronutrients such as vitamin D, calcium, and iron in mothers who used to have bariatric surgery and their babies have been shown to be lower than in mothers without a history of bariatric surgery. Moreover, vitamin A deficiency is shown to be more widespread in pregnancies after bariatric surgery, which leads to visual problems in newborns and premature delivery. However, complications such as the duration of hospitalization of newborns in the NICU, disease rate in the first 28 days of life and congenital anomalies are not significantly different in babies born to mothers undergoing bariatric surgery compared to the control group. In spite of the vast advantages following obesity surgeries, due to the catabolic conditions and severe weight loss followed by such major intervention and the probability of nutrients malnutrition in a pregnant woman and her baby, after having surgery, at least 12 to 18 months should be considered to get pregnant as a recovery period. In addition, taking essential supplements before and at least 6 months after this approach is recommended.

Keywords: bariatric surgery, pregnancy, malnutrition, vitamin and mineral deficiency

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Authors: Mihail Nagea, Olivera Lupescu, Nicolae Ciurea, Alexandru Dimitriu, Alina Grosu

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Introduction: As severe open injuries are more and more frequent in modern traumatology, threatening not only the integrity of the affected limb but even the life of the patients, new methods desired to cope with the consequences of these traumas were described. Vacuum therapy is one such method which has been described as enhancing healing in trauma with extensive soft-tissue injuries, included those with septic complications. Material and methods: Authors prospectively analyze 15 patients with severe lower limb trauma with MESS less than 6, with considerable soft tissue loss following initial debridement and fracture fixation. The patients needed serial debridements and vacuum therapy was applied after delayed healing due to initial severity of the trauma, for an average period of 12 days (7 - 23 days).In 7 cases vacuum therapy was applied for septic complications. Results: Within the study group, there were no local complications; secondary debridements were performed for all the patients and vacuum system was re-installed after these debridements. No amputations were needed. Medical records were reviewed in order to compare the outcome of the patients: the hospital stay, anti-microbial therapy, time to healing of the bone and soft tissues (there is no standard group to be compared with) and the result showed considerable improvements in the outcome of the patients. Conclusion: Vacuum therapy improves healing of the soft tissues, including those infected; hospital stay and the number of secondary necessary procedures are reduced. Therefore it is considered a valuable support in treating trauma of the limbs with severe soft tissue injuries.

Keywords: complex injuries, negative pressure, open fractures, wound therapy

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Authors: Yahya Asanoglu, Celaletdin Ergun

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Ceramic-matrix composites (CMC) have significant prominence in various engineering applications because of their heat resistance associated with an ability to withstand the brittle type of catastrophic failure. In this study, specific raw materials have been chosen for the purpose of having suitable CMC material for high-temperature dielectric applications. CMC material will be manufactured through the polymer infiltration and pyrolysis (PIP) method. During the manufacturing process, vacuum infiltration and autoclave will be applied so as to decrease porosity and obtain higher mechanical properties, although this advantage leads to a decrease in the electrical performance of the material. Time and temperature adjustment in pyrolysis parameters provide a significant difference in the properties of the resulting material. The mechanical and thermal properties will be investigated in addition to the measurement of dielectric constant and tangent loss values within the spectrum of Ku-band (12 to 18 GHz). Also, XRD, TGA/PTA analyses will be employed to prove the transition of precursor to ceramic phases and to detect critical transition temperatures. Additionally, SEM analysis on the fracture surfaces will be performed to see failure mechanism whether there is fiber pull-out, crack deflection and others which lead to ductility and toughness in the material. In this research, the cost-effectiveness and applicability of the PIP method will be proven in the manufacture of CMC materials while optimization of pyrolysis time, temperature and cycle for specific materials is detected by experiment. Also, several resins will be shown to be a potential raw material for CMC radome and antenna applications. This research will be distinguished from previous related papers due to the fact that in this research, the combination of different precursors and fabrics will be experimented with to specify the unique cons and pros of each combination. In this way, this is an experimental sum of previous works with unique PIP parameters and a guide to the manufacture of CMC radome and antenna.

Keywords: CMC, PIP, precursor, quartz

Procedia PDF Downloads 160

Authors: Mohammad Yousaf Safi Mohibullah Afghan

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The study made on Islamic and conventional banks scrutinizes the risks interconnected with credit and liquidity on the productivity performance of Islamic and conventional banks that operate in Pakistan. Among the banks, only 4 Islamic and 18 conventional banks have been selected to enrich the result of our study on Islamic banks performance in connection to conventional banks. The selection of the banks to the panel is based on collecting quarterly unbalanced data ranges from the first quarter of 2007 to the last quarter of 2017. The data are collected from the Bank’s web sites and State Bank of Pakistan. The data collection is carried out based on Delta-method test. The mentioned test is used to find out the empirical results. In the study, while collecting data on the banks, the return on assets and return on equity have been major factors that are used assignificant proxies in determining the profitability of the banks. Moreover, another major proxy is used in measuring credit and liquidity risks, the loan loss provision to total loan and the ratio of liquid assets to total liability. Meanwhile, with consideration to the previous literature, some other variables such as bank size, bank capital, bank branches, and bank employees have been used to tentatively control the impact of those factors whose direct and indirect effects on profitability is understood. In conclusion, the study emphasizes that credit risk affects return on asset and return on equity positively, and there is no significant difference in term of credit risk between Islamic and conventional banks. Similarly, the liquidity risk has a significant impact on the bank’s profitability, though the marginal effect of liquidity risk is higher for Islamic banks than conventional banks.

Keywords: islamic & conventional banks, performance return on equity, return on assets, pakistan banking sectors, profitibility

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Authors: Lucky Malise, Hilary Rutto, Tumisang Seodigeng

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The use of tires in automobiles is very important in the automobile industry. However, there is a serious environmental problem concerning the disposal of these rubber tires once they become worn out. The main aim of this study was to prepare activated carbon from waste tire pyrolysis char by impregnating KOH on pyrolytic char. Adsorption studies on lead onto chemically activated carbon was carried out using response surface methodology. The effect of process parameters such as temperature (°C), adsorbent dosage (g/1000ml), pH, contact time (minutes) and initial lead concentration (mg/l) on the adsorption capacity were investigated. It was found that the adsorption capacity increases with an increase in contact time, pH, temperature and decreases with an increase in lead concentration. Optimization of the process variables was done using a numerical optimization method. Fourier Transform Infrared Spectra (FTIR) analysis, XRay diffraction (XRD), Thermogravimetric analysis (TGA) and scanning electron microscope was used to characterize the pyrolytic carbon char before and after activation. The optimum points 1g/ 100 ml for adsorbent dosage, 7 for pH value of the solution, 115.2 min for contact time, 100 mg/l for initial metal concentration, and 25°C for temperature were obtained to achieve the highest adsorption capacity of 93.176 mg/g with a desirability of 0.994. Fourier Transform Infrared Spectra (FTIR) analysis and Thermogravimetric analysis (TGA) show the presence of oxygen-containing functional groups on the surface of the activated carbon produced and that the weight loss taking place during the activation step is small.

Keywords: waste tire pyrolysis char, chemical activation, central composite design (CCD), adsorption capacity, numerical optimization

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Authors: Catarina Cruz, Ana Breda

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Tiling problems have been capturing the attention of many mathematicians due to their real-life applications. In this study, we deal with tilings of Zⁿ by Lee spheres, where n is a positive integer number, being these tilings related with error correcting codes on the transmission of information over a noisy channel. We focus our attention on the question ‘for what values of n and r does the n-dimensional Lee sphere of radius r tile Zⁿ?’. It seems that the n-dimensional Lee sphere of radius r does not tile Zⁿ for n ≥ 3 and r ≥ 2. Here, we prove that is not possible to tile Z⁷ with Lee spheres of radius 2 presenting a proof based on a combinatorial method and faithful to the geometric idea of the problem. The non-existence of such tilings has been studied by several authors being considered the most difficult cases those in which the radius of the Lee spheres is equal to 2. The relation between these tilings and error correcting codes is established considering the center of a Lee sphere as a codeword and the other elements of the sphere as words which are decoded by the central codeword. When the Lee spheres of radius r centered at elements of a set M ⊂ Zⁿ tile Zⁿ, M is a perfect r-error correcting Lee code of word length n over Z, denoted by PL(n, r). Our strategy to prove the non-existence of PL(7, 2) codes are based on the assumption of the existence of such code M. Without loss of generality, we suppose that O ∈ M, where O = (0, ..., 0). In this sense and taking into account that we are dealing with Lee spheres of radius 2, O covers all words which are distant two or fewer units from it. By the definition of PL(7, 2) code, each word which is distant three units from O must be covered by a unique codeword of M. These words have to be covered by codewords which dist five units from O. We prove the non-existence of PL(7, 2) codes showing that it is not possible to cover all the referred words without superposition of Lee spheres whose centers are distant five units from O, contradicting the definition of PL(7, 2) code. We achieve this contradiction by combining the cardinality of particular subsets of codewords which are distant five units from O. There exists an extensive literature on codes in the Lee metric. Here, we present a new approach to prove the non-existence of PL(7, 2) codes.

Keywords: Golomb-Welch conjecture, Lee metric, perfect Lee codes, tilings

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Authors: Van-Thanh Ho, Jaiyoung Ryu

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In soft robotics, the optimization of fluid dynamics through pneumatic methods plays a pivotal role in enhancing operational efficiency and reducing energy loss. This is particularly crucial when replacing conventional techniques such as cable-driven electromechanical systems. The pneumatic model employed in this study represents a sophisticated framework designed to efficiently channel pressure from a high-pressure reservoir to various muscle locations on the robot's body. This intricate network involves a branching system of tubes. The study introduces a comprehensive pneumatic model, encompassing the components of a reservoir, tubes, and Pneumatically Actuated Muscles (PAM). The development of this model is rooted in the principles of shock tube theory. Notably, the study leverages experimental data to enhance the understanding of the interplay between the PAM structure and the surrounding fluid. This improved interactive approach involves the use of morphing motion, guided by a contraction function. The study's findings demonstrate a high degree of accuracy in predicting pressure distribution within the PAM. The model's predictive capabilities ensure that the error in comparison to experimental data remains below a threshold of 10%. Additionally, the research employs a machine learning model, specifically a surrogate model based on the Kriging method, to assess and quantify uncertainty factors related to the initial reservoir pressure and tube diameter. This comprehensive approach enhances our understanding of pneumatic soft robotics and its potential for improved operational efficiency.

Keywords: pneumatic artificial muscles, pressure drop, morhing motion, branched network, surrogate model

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Authors: Radka Obořilová, Hana Šimečková, Matěj Pastucha, Jan Přibyl, Petr Skládal, Ivana Mašlaňová, Zdeněk Farka

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Due to the spreading of antimicrobial resistance, alternative approaches to combat superinfections are being sought, both in the field of lysing agents and methods for studying bacterial lysis. A suitable alternative to antibiotics is phage therapy and enzybiotics, for which it is also necessary to study the mechanism of their action. Biosensor-based techniques allow rapid detection of pathogens in real time, verification of sensitivity to commonly used antimicrobial agents, and selection of suitable lysis agents. The detection of lysis takes place on the surface of the biosensor with immobilized bacteria, which has the potential to be used to study biofilms. An example of such a biosensor is surface plasmon resonance (SPR), which records the kinetics of bacterial lysis based on a change in the resonance angle. The bacteria are immobilized on the surface of the SPR chip, and the action of phage as the mass loss is monitored after a typical lytic cycle delay. Atomic force microscopy (AFM) is a technique for imaging of samples on the surface. In contrast to electron microscopy, it has the advantage of real-time imaging in the native conditions of the nutrient medium. In our case, Staphylococcus aureus was lysed using the enzyme lysostaphin and phage P68 from the familyPodoviridae at 37 ° C. In addition to visualization, AFM was used to study changes in mechanical properties during lysis, which resulted in a reduction of Young’s modulus (E) after disruption of the bacterial wall. Changes in E reflect the stiffness of the bacterium. These advanced methods provide deeper insight into bacterial lysis and can help to fight against bacterial diseases.

Keywords: biosensors, atomic force microscopy, surface plasmon resonance, bacterial lysis, staphylococcus aureus, phage P68

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Authors: Kamille Beye

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Critical thinking is a topic that has been disputed in the field of education for decades, but many resulting debates have centered around strengthening critical thinking capabilities in the societies, workforces, and educational centers of the global north. In contrast, this paper provides an analysis of the teaching of critical thinking in Liberia, which has been ravaged by years of war and a recent Ebola outbreak. These crises have decimated the Liberian education sector, leading to a loss of teaching capacities that are essential to providing critical thinking education. Until recently, critical thinking had no seat at the table when the future needs of the country were discussed by the government and non-governmental agencies. Now, the University of Liberia has a bold goal to become one of the top twenty universities in West Africa in the next seven years, which has led to a focus on teaching critical thinking skills to improve learning. This paper argues that critical thinking is essential to strengthening not only the Liberian education system, but for promoting peace amongst community members, and yet it suggests that commitments to the teaching of critical thinking in Liberia have hitherto been overly superficial. Based on an initial scoping study, this paper will examine the potential impacts of teaching critical thinking skills to undergraduate students in the William V. S. Tubman School of Education at the University of Liberia on continued peacebuilding and reconstruction efforts of the country. The research contends that if critical thinking skills are taught, practiced and continually utilized, teachers and students will have the ability to engage with information and negotiate challenges to solutions in ways that are beneficial to the communities in which they live. The research will use a variety of methods, that include the California Critical Thinking Disposition Inventory. This research will demonstrate that critical thinking skills are not only needed for entering the workforce, but necessary for negotiating and expressing the needs and desires of local communities in a peaceful way.

Keywords: critical thinking, higher education, Liberia, peacebuilding, post-conflict

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Authors: Foad Hassaninejadafarahani, Scott Ormiston

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Reflux condensation occurs in a vertical channels and tubes when there is an upward core flow of vapor (or gas-vapor mixture) and a downward flow of the liquid film. The understanding of this condensation configuration is crucial in the design of reflux condensers, distillation columns, and in loss-of-coolant safety analyses in nuclear power plant steam generators. The unique feature of this flow is the upward flow of the vapor-gas mixture (or pure vapor) that retards the liquid flow via shear at the liquid-mixture interface. The present model solves the full, elliptic governing equations in both the film and the gas-vapor core flow. The computational mesh is non-orthogonal and adapts dynamically the phase interface, thus produces sharp and accurate interface. Shear forces and heat and mass transfer at the interface are accounted for fundamentally. This modeling is a big step ahead of current capabilities by removing the limitations of previous reflux condensation models which inherently cannot account for the detailed local balances of shear, mass, and heat transfer at the interface. Discretisation has been done based on a finite volume method and a co-located variable storage scheme. An in-house computer code was developed to implement the numerical solution scheme. Detailed results are presented for laminar reflux condensation from steam-air mixtures flowing in vertical parallel plate channels. The results include velocity and pressure profiles, as well as axial variations of film thickness, Nusselt number and interface gas mass fraction.

Keywords: Reflux, Condensation, CFD-Two Phase, Nusselt number

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Authors: Camelia Porey, Binaya Kumar Jaiswal

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BACKGROUND: Antiphospholipid antibody (APLA) syndrome is an autoimmune disorder predisposing to thrombotic complications affecting CNS either by arterial vasooclusion or venous thrombosis. Cerebral venous sinus thrombosis (CVST) secondarily causes raised intracranial pressure (ICP). However, intracranial hypertension without evidence of CVST is a rare entity. Here we present two cases of elevated ICP with absence of identifiable CVST. CASE SUMMARY: Case 1, 28-year female had a 2 months history of holocranial headache followed by bilateral painless vision loss reaching lack of light perception over 20 days. CSF opening pressure was elevated. Fundoscopy showed bilateral grade 4 papilledema. MRI revealed a partially empty sella with bilateral optic nerve tortuosity. Idiopathic intracranial hypertension (IIH) was diagnosed. With acetazolamide, there was complete resolution of the clinical and radiological abnormalities. 5 months later she presented with acute onset right-sided hemiparesis. MRI was suggestive of acute left MCA infarct.MR venogram was normal. APLA came positive with high titres of Anticardiolipin and Beta 2 glycoprotein both IgG and IgM. Case 2, 23-year female, presented with headache and diplopia of 2 months duration. CSF pressure was elevated and Grade 3 papilledema was seen. MRI showed bilateral optic nerve hyperintensities with nerve head protrusion with normal MRV. APLA profile showed elevated beta 2 glycoprotein IgG and IgA. CONCLUSION: This is an important non thrombotic complication of APLA syndrome and requires further large-scale study for insight into the pathogenesis and early recognition to avoid future complications.

Keywords: APLA syndrome, idiopathic intracranial hypertension, MR venogram, papilledema

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Authors: Bradley Fevrier

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Background: Type 2 diabetes mellitus, a non-communicable metabolic disorder, is a fast-growing problem for health, as it presents numerous complications and death worldwide. St. Lucia, much like most other emerging nation in the Caribbean, struggles with the management of type 2 diabetes mellitus (T2DM) among its populace. Good knowledge, attitude, and practices [KAP] of T2DM are essential in the prevention and management of this disease.Lifestyle adaptation, including increased knowledge, positive attitude, and efficient practice towards lifestyle modifications, can avert the advancement of difficulties associated with diabetes. Methods: An institutional-based cross-sectional study was conducted during the period June 15, 2022, to July15 2022. Data were collected by using the self-administered questionnaire designed to collect the required information from participants, and the data wasanalyzed using the statistical package for social science (SPSS) version 26. Knowledge, attitude, and practice of lifestyle modification among participants were determined using descriptive statistics. Results: A total of 402 participants completed the study, fully yielding an 84% response rate. Overall, the assessed levels of KAP relating to the life-threatening complications of T2DM were moderate. Results further indicated that women outnumbered men 68.4% to 31.6%, respectively. Significant positive correlation (r= 0.244, p<0.001) and (r=.203, p<0.001) were found between the knowledge level as well as the attitude level of study respondents. Conclusion: The overall study findings regarding the level of knowledge and attitude concerning lifestyle modifications among study participants were interpreted as generally high. However, the practice of healthy lifestyle modification habits was poor. The current findings suggest a need for structured educational campaigns prioritizing the importance of lifestyle modifications (weight loss, smoking cessation, physical exercise) to the general population.

Keywords: Diabetes, knowledge, lifestyle, survey

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Authors: Fatemeh Rezaei, Mohammad H. Yarmohammadian, Masoud Ferdosi, Abbas Haghshnas

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Background: Failure Modes and Effect Analysis is now having known as the main methods of risk assessment and the accreditation requirements for many organizations. The Risk Priority Number (RPN) approach is generally preferred, especially for its easiness of use. Indeed it does not require statistical data, but it is based on subjective evaluations given by the experts about the Occurrence (O i), the Severity (Si) and the Detectability (D i) of each cause of failure. Methods: This study is a quantitative – qualitative research. In terms of qualitative dimension, method of focus groups with inductive approach is used. To evaluate the results of the qualitative study, quantitative assessment was conducted to calculate RPN score. Results; We have studied patient’s journey process in surgery ward and the most important phase of the process determined Transport of the patient from the holding area to the operating room. Failures of the phase with the highest priority determined by defining inclusion criteria included severity (clinical effect, claim consequence, waste of time and financial loss), occurrence (time- unit occurrence and degree of exposure to risk) and preventability (degree of preventability and defensive barriers) and quantifying risks priority criteria in the context of RPN index. Ability of improved RPN reassess by root cause (RCA) analysis showed some variations. Conclusions: Finally, It could be concluded that understandable criteria should have been developed according to personnel specialized language and communication field. Therefore, participation of both technical and clinical groups is necessary to modify and apply these models.

Keywords: failure mode, effects analysis, risk priority number(RPN), health system, risk assessment

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Authors: Meseret Gebeyehu Yehuala

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Women represent the majority of urban farmers engaged in vegetable and fruit production in Bahir Dar, Ethiopia. We examine urban agriculture in Bahir Dar city in the context of disruptions caused by the civil war and COVID-19. The Sustainable Livelihoods Framework serves as a conceptual frame to explore the vulnerability context, the structural and institutional challenges faced by women, and how this impacts their livelihoods. A total of 25 urban women farmers and 6 key informants were involved in the study through explorative and structured interviews conducted in 2021. Observations and informal conversations during repeated visits provided deeper insights. In addition, key informants employed in civil service institutions and experts were interviewed. Data were analysed by applying qualitative content analysis by using Atlas tia software. Women report that they experience a lack of access to land, insecurity of tenure, irregular technical support and input provision by agricultural extension services, and lack of access to credit and formal marketplaces. The COVID-19 pandemic restrictions aggravated this situation by delaying agricultural extension offices’ provision of necessary inputs and disrupting food handling and storage leading to the loss of perishable products. Bombing in relation to the civil war has destroyed harvests and left women in fear of returning to their fields. Women stated that vegetable and fruit production could contribute to their incomes, household food supplies, and more diversified diets. However, the city municipal office has, so far, not committed to supporting urban agriculture as a livelihood strategy.

Keywords: urban agriculture, institutional challenges, Bahir Dar, sustainable livelihood framework

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Authors: Sang Koo Jeon, Seung Hoon Nahm, Oh Heon Kwon

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The unit cell of solid oxide fuel cell (SOFC) must be stacked as several layers type to obtain the high power. The most of researcher have concerned about the performance of stacked SOFC rather than the structural stability of stacked SOFC and especially interested how to design for reducing the electrical loss and improving the high efficiency. Consequently, the stacked SOFC able to produce the electrical high power and related parts like as manifold, gas seal, bipolar plate were developed to optimize the stack design. However, the unit cell of SOFC was just layered on the interconnector without the adhesion and the hydrogen and oxygen were injected to the interfacial layer in the high temperature. On the operating condition, the interfacial layer can be the one of the weak point in the stacked SOFC. Therefore the evaluation of the structural safety for the failure is essentially needed. In this study, interfacial adhesion between SOFC and metal adhesive was estimated in the high temperature environment. The metal adhesive was used to strongly connect the unit cell of SOFC with interconnector and provide the electrical conductivity between them. The four point bending test was performed to measure the interfacial adhesion. The unit cell of SOFC and SiO2 wafer were diced and then attached by metal adhesive. The SiO2 wafer had the center notch to initiate a crack from the tip of the notch. The modified stereomicroscope combined with the CCD camera and system for measuring the length was used to observe the fracture behavior. Additionally, the interfacial adhesion was evaluated in the high temperature condition because the metal adhesive was affected by high temperature. Also the specimen was exposed in the furnace during several hours and then the interfacial adhesion was evaluated. Finally, the interfacial adhesion energy was quantitatively determined and compared in the each condition.

Keywords: solid oxide fuel cell (SOFC), metal adhesive, adhesion, high temperature

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Authors: Hussain Sajid, Jung-Hun Shin, Kum-Won Cho

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Image super-resolution is the most common computer vision problem with many important applications. Generative adversarial networks (GANs) have promoted remarkable advances in single-image super-resolution (SR) by recovering photo-realistic images. However, high memory requirements of GAN-based SR (mainly generators) lead to performance degradation and increased energy consumption, making it difficult to implement it onto resource-constricted devices. To relieve such a problem, In this paper, we introduce an optimized and highly efficient architecture for SR-GAN (generator) model by utilizing model compression techniques such as Knowledge Distillation and pruning, which work together to reduce the storage requirement of the model also increase in their performance. Our method begins with distilling the knowledge from a large pre-trained model to a lightweight model using different loss functions. Then, iterative weight pruning is applied to the distilled model to remove less significant weights based on their magnitude, resulting in a sparser network. Knowledge Distillation reduces the model size by 40%; pruning then reduces it further by 18%. To accelerate the learning process, we employ the Horovod framework for distributed training on a cluster of 2 nodes, each with 8 GPUs, resulting in improved training performance and faster convergence. Experimental results on various benchmarks demonstrate that the proposed compressed model significantly outperforms state-of-the-art methods in terms of peak signal-to-noise ratio (PSNR), structural similarity index measure (SSIM), and image quality for x4 super-resolution tasks.

Keywords: single-image super-resolution, generative adversarial networks, knowledge distillation, pruning

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