Search results for: cubic normal distribution
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 7778

Search results for: cubic normal distribution

5708 A Superposition Method in Analyses of Clamped Thick Plates

Authors: Alexander Matrosov, Guriy Shirunov

Abstract:

A superposition method based on Lame's idea is used to get a general analytical solution to analyze a stress and strain state of a rectangular isotropjc elastic thick plate. The solution is built by using three solutions of the method of initial functions in the form of double trigonometric series. The results of bending of a thick plate under normal stress on its top face with two opposite sides clamped while others free of load are presented and compared with FEM modelling.

Keywords: general solution, method of initial functions, superposition method, thick isotropic plates

Procedia PDF Downloads 593
5707 Two-Dimensional CFD Simulation of the Behaviors of Ferromagnetic Nanoparticles in Channel

Authors: Farhad Aalizadeh, Ali Moosavi

Abstract:

This paper presents a two-dimensional Computational Fluid Dynamics (CFDs) simulation for the steady, particle tracking. The purpose of this paper is applied magnetic field effect on Magnetic Nanoparticles velocities distribution. It is shown that the permeability of the particles determines the effect of the magnetic field on the deposition of the particles and the deposition of the particles is inversely proportional to the Reynolds number. Using MHD and its property it is possible to control the flow velocity, remove the fouling on the walls and return the system to its original form. we consider a channel 2D geometry and solve for the resulting spatial distribution of particles. According to obtained results when only magnetic fields are applied perpendicular to the flow, local particles velocity is decreased due to the direct effect of the magnetic field return the system to its original fom. In the method first, in order to avoid mixing with blood, the ferromagnetic particles are covered with a gel-like chemical composition and are injected into the blood vessels. Then, a magnetic field source with a specified distance from the vessel is used and the particles are guided to the affected area. This paper presents a two-dimensional Computational Fluid Dynamics (CFDs) simulation for the steady, laminar flow of an incompressible magnetorheological (MR) fluid between two fixed parallel plates in the presence of a uniform magnetic field. The purpose of this study is to develop a numerical tool that is able to simulate MR fluids flow in valve mode and determineB0, applied magnetic field effect on flow velocities and pressure distributions.

Keywords: MHD, channel clots, magnetic nanoparticles, simulations

Procedia PDF Downloads 365
5706 Studying the Value-Added Chain for the Fish Distribution Process at Quang Binh Fishing Port in Vietnam

Authors: Van Chung Nguyen

Abstract:

The purpose of this study is to study the current status of the value chain for fish distribution at Quang Binh Fishing Port with 360 research samples in which the research subjects are fishermen, traders, retailers, and businesses. The research uses the approach of applying the value chain theoretical framework of Kaplinsky and Morris to quantify and describe market channels and actors participating in the value chain and analyze the value-added process of these companies according to market channels. The analysis results show that fishermen directly catch fish with high economic efficiency, but processing enterprises and, especially retailers, are the agents to obtain higher added value. Processing enterprises play a role that is not really clear due to outdated processing technology; in contrast, retailers have the highest added value. This shows that the added value of the fish supply chain at Quang Binh fishing port is still limited, leading to low output quality. Therefore, the selling price of fish to the market is still high compared to the abundant fish resources, leading to low consumption and limiting exports due to the quality of processing enterprises. This reduces demand and fishing capacity, and productivity is lower than potential. To improve the fish value chain at fishing ports, it is necessary to focus on improving product quality, strengthening linkages between actors, building brands and product consumption markets at the same time, improving the capacity of export processing enterprises.

Keywords: Quang Binh fishing port, value chain, market, distributions channel

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5705 Pharmacokinetic and Tissue Distribution of Etoposide Loaded Modified Glycol Chitosan Nanoparticles

Authors: Akhtar Aman, Abida Raza, Shumaila Bashir, Mehboob Alam

Abstract:

The development of efficient delivery systems remains a major concern in cancer chemotherapy as many efficacious anticancer drugs are hydrophobic and difficult to formulate. Nanomedicines based on drug-loaded amphiphilic glycol chitosan micelles offer potential advantages for the formulation of drugs such as etoposide that may improve the pharmacokinetics and reduce the formulation-related adverse effects observed with current formulations. Amphiphilic derivatives of glycol chitosan were synthesized by chemical grafting of palmitic acid N-hydroxysuccinimide and quaternization to glycol chitosan backbone. To this end, a 7.9 kDa glycol chitosan was modified by palmitoylation and quaternization, yielding a 13 kDa amphiphilic polymer. Micelles prepared from this amphiphilic polymer had a size of 162nm and were able to encapsulate up to 3 mg/ml etoposide. Pharmacokinetic results indicated that the GCPQ micelles transformed the biodistribution pattern and increased etoposide concentration in the brain significantly compared to free drugs after intravenous administration. AUC 0.5-24h showed statistically significant difference in ETP-GCPQ vs. Commercial preparation in liver (25 vs.70, p<0.001), spleen (27 vs.36, p<0.05), lungs (42 vs.136,p<0.001),kidneys(25 vs.70,p< 0.05),and brain(19 vs.9,p<0.001). ETP-GCPQ crossed the blood-brain barrier, and 4, 3.5, 2.6, 1.8, 1.7, 1.5, and 2.5 fold higher levels of etoposide were observed at 0.5, 1, 2, 4, 6, 12, and 24hrs; respectively suggesting these systems could deliver hydrophobic anticancer drugs such as etoposide to tumors but also increased their transport through the biological barriers, thus making it a good delivery system

Keywords: glycol chitosan, micelles, pharmacokinetics, tissue distribution

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5704 Self-Assembly of TaC@Ta Core-Shell-Like Nanocomposite Film via Solid-State Dewetting: Toward Superior Wear and Corrosion Resistance

Authors: Ping Ren, Mao Wen, Kan Zhang, Weitao Zheng

Abstract:

The improvement of comprehensive properties including hardness, toughness, wear, and corrosion resistance in the transition metal carbides/nitrides TMCN films, especially avoiding the trade-off between hardness and toughness, is strongly required to adapt to various applications. Although incorporating ductile metal DM phase into the TMCN via thermally-induced phase separation has been emerged as an effective approach to toughen TMCN-based films, the DM is just limited to some soft ductile metal (i.e. Cu, Ag, Au immiscibility with the TMCN. Moreover, hardness is highly sensitive to soft DM content and can be significantly worsened. Hence, a novel preparation method should be attempted to broaden the DM selection and assemble much more ordered nanocomposite structure for improving the comprehensive properties. Here, we provide a new strategy, by activating solid-state dewetting during layered deposition, to accomplish the self-assembly of ordered TaC@Ta core-shell-like nanocomposite film consisting of TaC nanocrystalline encapsulated with thin pseudocrystal Ta tissue. That results in the superhard (~45.1 GPa) dominated by Orowan strengthening mechanism and high toughness attributed to indenter-induced phase transformation from the pseudocrystal to body-centered cubic Ta, together with the drastically enhanced wear and corrosion resistance. Furthermore, very thin pseudocrystal Ta encapsulated layer (~1.5 nm) in the TaC@Ta core-shell-like structure helps for promoting the formation of lubricious TaOₓ Magnéli phase during sliding, thereby further dropping the coefficient of friction. Apparently, solid-state dewetting may provide a new route to construct ordered TMC(N)@TM core-shell-like nanocomposite capable of combining superhard, high toughness, low friction, superior wear with corrosion resistance.

Keywords: corrosion, nanocomposite film, solid-state dewetting, tribology

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5703 Experiment-Based Teaching Method for the Varying Frictional Coefficient

Authors: Mihaly Homostrei, Tamas Simon, Dorottya Schnider

Abstract:

The topic of oscillation in physics is one of the key ideas which is usually taught based on the concept of harmonic oscillation. It can be an interesting activity to deal with a frictional oscillator in advanced high school classes or in university courses. Its mechanics are investigated in this research, which shows that the motion of the frictional oscillator is more complicated than a simple harmonic oscillator. The physics of the applied model in this study seems to be interesting and useful for undergraduate students. The study presents a well-known physical system, which is mostly discussed theoretically in high school and at the university. The ideal frictional oscillator is normally used as an example of harmonic oscillatory motion, as its theory relies on the constant coefficient of sliding friction. The structure of the system is simple: a rod with a homogeneous mass distribution is placed on two rotating identical cylinders placed at the same height so that they are horizontally aligned, and they rotate at the same angular velocity, however in opposite directions. Based on this setup, one could easily show that the equation of motion describes a harmonic oscillation considering the magnitudes of the normal forces in the system as the function of the position and the frictional forces with a constant coefficient of frictions are related to them. Therefore, the whole description of the model relies on simple Newtonian mechanics, which is available for students even in high school. On the other hand, the phenomenon of the described frictional oscillator does not seem to be so straightforward after all; experiments show that the simple harmonic oscillation cannot be observed in all cases, and the system performs a much more complex movement, whereby the rod adjusts itself to a non-harmonic oscillation with a nonzero stable amplitude after an unconventional damping effect. The stable amplitude, in this case, means that the position function of the rod converges to a harmonic oscillation with a constant amplitude. This leads to the idea of a more complex model which can describe the motion of the rod in a more accurate way. The main difference to the original equation of motion is the concept that the frictional coefficient varies with the relative velocity. This dependence on the velocity was investigated in many different research articles as well; however, this specific problem could demonstrate the key concept of the varying friction coefficient and its importance in an interesting and demonstrative way. The position function of the rod is described by a more complicated and non-trivial, yet more precise equation than the usual harmonic oscillation description of the movement. The study discusses the structure of the measurements related to the frictional oscillator, the qualitative and quantitative derivation of the theory, and the comparison of the final theoretical function as well as the measured position-function in time. The project provides useful materials and knowledge for undergraduate students and a new perspective in university physics education.

Keywords: friction, frictional coefficient, non-harmonic oscillator, physics education

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5702 Comprehensive Analysis of RNA m5C Regulator ALYREF as a Suppressive Factor of Anti-tumor Immune and a Potential Tumor Prognostic Marker in Pan-Cancer

Authors: Yujie Yuan, Yiyang Fan, Hong Fan

Abstract:

Objective: The RNA methylation recognition protein Aly/REF export factor (ALYREF) is considered one type of “reader” protein acting as a recognition protein of m5C, has been reported involved in several biological progresses including cancer initiation and progression. 5-methylcytosine (m5C) is a conserved and prevalent RNA modification in all species, as accumulating evidence suggests its role in the promotion of tumorigenesis. It has been claimed that ALYREF mediates nuclear export of mRNA with m5C modification and regulates biological effects of cancer cells. However, the systematical regulatory pathways of ALYREF in cancer tissues have not been clarified, yet. Methods: The expression level of ALYREF in pan-cancer and their normal tissues was compared through the data acquired from The Cancer Genome Atlas (TCGA). The University of Alabama at Birmingham Cancer data analysis Portal UALCAN was used to analyze the relationship between ALYREF and clinical pathological features. The relationship between the expression level of ALYREF and prognosis of pan-cancer, and the correlation genes of ALYREF were figured out by using Gene Expression Correlation Analysis database GEPIA. Immune related genes were obtained from TISIDB (an integrated repository portal for tumor-immune system interactions). Immune-related research was conducted by using Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data (ESTIMATE) and TIMER. Results: Based on the data acquired from TCGA, ALYREF has an obviously higher-level expression in various types of cancers compared with relevant normal tissues excluding thyroid carcinoma and kidney chromophobe. The immunohistochemical images on The Human Protein Atlas showed that ALYREF can be detected in cytoplasm, membrane, but mainly located in nuclear. In addition, a higher expression level of ALYREF in tumor tissue generates a poor prognosis in majority of cancers. According to the above results, cancers with a higher expression level of ALYREF compared with normal tissues and a significant correlation between ALYREF and prognosis were selected for further analysis. By using TISIDB, we found that portion of ALYREF co-expression genes (such as BIRC5, H2AFZ, CCDC137, TK1, and PPM1G) with high Pearson correlation coefficient (PCC) were involved in anti-tumor immunity or affect resistance or sensitivity to T cell-mediated killing. Furthermore, based on the results acquired from GEPIA, there was significant correlation between ALYREF and PD-L1. It was exposed that there is a negative correlation between the expression level of ALYREF and ESTIMATE score. Conclusion: The present study indicated that ALYREF plays a vital and universal role in cancer initiation and progression of pan-cancer through regulating mitotic progression, DNA synthesis and metabolic process, and RNA processing. The correlation between ALYREF and PD-L1 implied ALYREF may affect the therapeutic effect of immunotherapy of tumor. More evidence revealed that ALYREF may play an important role in tumor immunomodulation. The correlation between ALYREF and immune cell infiltration level indicated that ALYREF can be a potential therapeutic target. Exploring the regulatory mechanism of ALYREF in tumor tissues may expose the reason for poor efficacy of immunotherapy and offer more directions of tumor treatment.

Keywords: ALYREF, pan-cancer, immunotherapy, PD-L1

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5701 Effects of Exercise in the Cold on Glycolipid Metabolism and Insulin Sensitivity in Obese Rats

Authors: Chaoge Wang, Xiquan Weng, Yan Meng, Wentao Lin

Abstract:

Objective: Cold exposure and exercise serve as two physiological stimuli to glycolipid metabolism and insulin sensitivity. So far, it remains to be elucidated whether exercise plus cold exposure can produce an addictive effect on promoting glycolipid metabolism and insulin sensitivity. Methods: 64 SD rats were subjected to high-fat and high-sugar diets for 9-week and sucessfully to establish an obesity model. They were randomly divided into 8 groups: normal control group (NC), normal exercise group (NE), continuous cold control group (CC), continuous cold exercise group (CE), acute clod control group (AC), acute cold exercise group (AE), intermittent cold control group (IC) and intermittent cold exercise group (IE). For continuous cold exposure, the rats stayed in a cold environment all day; for acute cold exposure, the rats were exposed to cold for only 4h before the end of the experiment; for intermittent cold exposure, the rats were exposed to cold for 4h per day. The protocol for treadmill runnings were as follows: 25m/min (speed), 0°C (slope), 30 mins each time, an interval for 10 mins between two runnings, twice/two days, lasting for 5 weeks. Sampling were conducted on the 5th weekend. Blood lipids, free fatty acids, blood glucose (FBG), and serum insulin (FINS) were examined, and the insulin resistance index (HOMA-IR = FBG (mmol/L)×FINS(mIU/L)/22.5) was calculated. SPSS 22.0 was used for statistical analysis of the experimental results, and the ANOVA analysis was performed between groups (p < 0.05 was significant). Results: (1) Compared with the NC group, the FBG of the rats was significantly declined in the NE, CE, AC, AE, and IE groups (p < 0.05), the FINS of the rats was significantly declined in the AE group (p < 0.05), the HOMA-IR of the rats was significantly declined in the NE, CE, AC, AE and IE groups (p < 0.05). Compared with the NE group, the FBG of the rats was significantly declined in the CE, AE, and IE groups (p < 0.05), the FINS and HOMA-IR of the rats were significantly declined in the AE group (p < 0.05). (2) Compared with the NC group, the CHO, TG, LDL-C, and FFA of the rats were significantly declined in CE and IE groups (p < 0.05), the HDL-C of the rats was significantly higher in NE, CC, CE, AE, and IE groups (p < 0.05). Compared with the NE group, the HDL-C of the rats was significantly higher in the CE and IE groups (p < 0.05). Conclusions: Sedentariness or exercise in the acute cold doesn't make sense in the treatment of type 2 diabetes, which led to one-off increases of the body's insulin sensitivity. Exercise in the continuous and intermittent cold can effectively decline the FBG, TC, TG, LDL-C, and FFA levels and increase the HDL-C level and insulin sensitivity in obese rats. These results can impact the prevention and treatment of type 2 diabetes.

Keywords: cold, exercise, insulin sensitivity, obesity

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5700 Optimization of Bifurcation Performance on Pneumatic Branched Networks in next Generation Soft Robots

Authors: Van-Thanh Ho, Hyoungsoon Lee, Jaiyoung Ryu

Abstract:

Efficient pressure distribution within soft robotic systems, specifically to the pneumatic artificial muscle (PAM) regions, is essential to minimize energy consumption. This optimization involves adjusting reservoir pressure, pipe diameter, and branching network layout to reduce flow speed and pressure drop while enhancing flow efficiency. The outcome of this optimization is a lightweight power source and reduced mechanical impedance, enabling extended wear and movement. To achieve this, a branching network system was created by combining pipe components and intricate cross-sectional area variations, employing the principle of minimal work based on a complete virtual human exosuit. The results indicate that modifying the cross-sectional area of the branching network, gradually decreasing it, reduces velocity and enhances momentum compensation, preventing flow disturbances at separation regions. These optimized designs achieve uniform velocity distribution (uniformity index > 94%) prior to entering the connection pipe, with a pressure drop of less than 5%. The design must also consider the length-to-diameter ratio for fluid dynamic performance and production cost. This approach can be utilized to create a comprehensive PAM system, integrating well-designed tube networks and complex pneumatic models.

Keywords: pneumatic artificial muscles, pipe networks, pressure drop, compressible turbulent flow, uniformity flow, murray's law

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5699 Study on the Relative Factors of Introducing Table Vinegar in Reducing Urinary Tract Infection in Patients with Long-Term Indwelling Catheter

Authors: Yu-Ju Hsieh, Lin-Hung Lin, Wen-Hui Chang

Abstract:

This study was designed as an interventional research and intended to validate whether the introduction of drinking vinegar every day can reduce and even prevent urinary tract infection in Taiwan home stayed disabilities who using indwelling catheter. The data was collected from the subjects who have received home care case at northern Taiwan, according to the questionnaire and a medical records retroactive methodology, the subjects were informed and consent to drink 15ml of table vinegar in a daily diet, and through routine urine testing and culture study. Home care nurses would assist collecting urine at the point of before and after a meal from total 35 studied subjects per month, and total collected 4 times for testing. The results showed that when the average age of study subjects was 65.46 years and catheter indwelling time was 15 years, drinking table vinegar could inhibit the activity of E. coli O157: H7 and reduce its breeding. Before drinking table vinegar daily, the subjects’ urine pH value was 7.0-8.0, and the average was 7.5, and the urine PH value dropped to 6.5 after drinking table vinegar for a month. There were two purple urine cases whose urine were changed from purple to normal color after two weeks of drinking, and the protein and bacteria values of urine gradually improved. Urine smell unpleasant before attending to this study, and the symptom improved significantly only after 1 week, and the urine smell returned to normal ammonia and became clean after 1 month later. None of these subjects received treatment in a hospital due to urinary tract infection, and there were no signs of bleeding in all cases during this study. The subjects of this study are chronic patients with a long-term bedridden catheterization; drinking cranberry juice is an economic burden for them, and also highly prohibited for diabetes patients. By adapting to use cheaper table vinegar to acidified urine and improve its smell and ease Purple Urine Syndrome, to furthermore, proven urinary tract infection, it can also to reduce the financial burden on families, the cost of social resources and the rate of re-admission.

Keywords: table vinegar, urinary tract infection, disability patients, long-term indwelling catheter

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5698 Reorientation of Anisotropic Particles in Free Liquid Microjets

Authors: Mathias Schlenk, Susanne Seibt, Sabine Rosenfeldt, Josef Breu, Stephan Foerster

Abstract:

Thin liquid jets on micrometer scale play an important role in processing such as in fiber fabrication, inkjet printing, but also for sample delivery in modern synchrotron X-ray devices. In all these cases the liquid jets contain solvents and dissolved materials such as polymers, nanoparticles, fibers pigments or proteins. As liquid flow in liquid jets differs significantly from flow in capillaries and microchannels, particle localization and orientation will also be different. This is of critical importance for applications, which depend on well-defined homogeneous particle and fiber distribution and orientation in liquid jets. Investigations of particle orientation in liquid microjets of diluted solutions have been rare, despite their importance. With the arise of micro-focused X-ray beams it has become possible to scan across samples with micrometer resolution to locally analyse structure and orientation of the samples. In the present work, we used this method to scan across liquid microjets to determine the local distribution and orientation of anisotropic particles. The compromise wormlike block copolymer micelles as an example of long flexible fibrous structures, hectorite materials as a model of extended nanosheet structures, and gold nanorods as an illustration of short stiff cylinders to comprise all relevant anisotropic geometries. We find that due to the different velocity profile in the liquid jet, which resembles plug flow, the orientation of the particles which was generated in the capillary is lost or changed into non-oriented or bi-axially orientations depending on the geometrical shape of the particle.

Keywords: anisotropic particles, liquid microjets, reorientation, SAXS

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5697 Examining Litter Distributions in Lethbridge, Alberta, Canada, Using Citizen Science and GIS Methods: OpenLitterMap App and Story Maps

Authors: Tali Neta

Abstract:

Humans’ impact on the environment has been incredibly brutal, with enormous plastic- and other pollutants (e.g., cigarette buds, paper cups, tires) worldwide. On land, litter costs taxpayers a fortune. Most of the litter pollution comes from the land, yet it is one of the greatest hazards to marine environments. Due to spatial and temporal limitations, previous litter data covered very small areas. Currently, smartphones can be used to obtain information on various pollutants (through citizen science), and they can greatly assist in acknowledging and mitigating the environmental impact of litter. Litter app data, such as the Litterati, are available for study through a global map only; these data are not available for download, and it is not clear whether irrelevant hashtags have been eliminated. Instagram and Twitter open-source geospatial data are available for download; however, these are considered inaccurate, computationally challenging, and impossible to quantify. Therefore, the resulting data are of poor quality. Other downloadable geospatial data (e.g., Marine Debris Tracker8 and Clean Swell10) are focused on marine- rather than terrestrial litter. Therefore, accurate terrestrial geospatial documentation of litter distribution is needed to improve environmental awareness. The current research employed citizen science to examine litter distribution in Lethbridge, Alberta, Canada, using the OpenLitterMap (OLM) app. The OLM app is an application used to track litter worldwide, and it can mark litter locations through photo georeferencing, which can be presented through GIS-designed maps. The OLM app provides open-source data that can be downloaded. It also offers information on various litter types and “hot-spots” areas where litter accumulates. In this study, Lethbridge College students collected litter data with the OLM app. The students produced GIS Story Maps (interactive web GIS illustrations) and presented these to school children to improve awareness of litter's impact on environmental health. Preliminary results indicate that towards the Lethbridge Coulees’ (valleys) East edges, the amount of litter significantly increased due to shrubs’ presence, that acted as litter catches. As wind generally travels from west to east in Lethbridge, litter in West-Lethbridge often finds its way down in the east part of the coulees. The students’ documented various litter types, while the majority (75%) included plastic and paper food packaging. The students also found metal wires, broken glass, plastic bottles, golf balls, and tires. Presentations of the Story Maps to school children had a significant impact, as the children voluntarily collected litter during school recess, and they were looking into solutions to reduce litter. Further litter distribution documentation through Citizen Science is needed to improve public awareness. Additionally, future research will be focused on Drone imagery of highly concentrated litter areas. Finally, a time series analysis of litter distribution will help us determine whether public education through Citizen Science and Story Maps can assist in reducing litter and reaching a cleaner and healthier environment.

Keywords: citizen science, litter pollution, Open Litter Map, GIS Story Map

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5696 The Potential Involvement of Platelet Indices in Insulin Resistance in Morbid Obese Children

Authors: Orkide Donma, Mustafa M. Donma

Abstract:

Association between insulin resistance (IR) and hematological parameters has long been a matter of interest. Within this context, body mass index (BMI), red blood cells, white blood cells and platelets were involved in this discussion. Parameters related to platelets associated with IR may be useful indicators for the identification of IR. Platelet indices such as mean platelet volume (MPV), platelet distribution width (PDW) and plateletcrit (PCT) are being questioned for their possible association with IR. The aim of this study was to investigate the association between platelet (PLT) count as well as PLT indices and the surrogate indices used to determine IR in morbid obese (MO) children. A total of 167 children participated in the study. Three groups were constituted. The number of cases was 34, 97 and 36 children in the normal BMI, MO and metabolic syndrome (MetS) groups, respectively. Sex- and age-dependent BMI-based percentile tables prepared by World Health Organization were used for the definition of morbid obesity. MetS criteria were determined. BMI values, homeostatic model assessment for IR (HOMA-IR), alanine transaminase-to-aspartate transaminase ratio (ALT/AST) and diagnostic obesity notation model assessment laboratory (DONMA-lab) index values were computed. PLT count and indices were analyzed using automated hematology analyzer. Data were collected for statistical analysis using SPSS for Windows. Arithmetic mean and standard deviation were calculated. Mean values of PLT-related parameters in both control and study groups were compared by one-way ANOVA followed by Tukey post hoc tests to determine whether a significant difference exists among the groups. The correlation analyses between PLT as well as IR indices were performed. Statistically significant difference was accepted as p-value < 0.05. Increased values were detected for PLT (p < 0.01) and PCT (p > 0.05) in MO group compared to those observed in children with N-BMI. Significant increases for PLT (p < 0.01) and PCT (p < 0.05) were observed in MetS group in comparison with the values obtained in children with N-BMI (p < 0.01). Significantly lower MPV and PDW values were obtained in MO group compared to the control group (p < 0.01). HOMA-IR (p < 0.05), DONMA-lab index (p < 0.001) and ALT/AST (p < 0.001) values in MO and MetS groups were significantly increased compared to the N-BMI group. On the other hand, DONMA-lab index values also differed between MO and MetS groups (p < 0.001). In the MO group, PLT was negatively correlated with MPV and PDW values. These correlations were not observed in the N-BMI group. None of the IR indices exhibited a correlation with PLT and PLT indices in the N-BMI group. HOMA-IR showed significant correlations both with PLT and PCT in the MO group. All of the three IR indices were well-correlated with each other in all groups. These findings point out the missing link between IR and PLT activation. In conclusion, PLT and PCT may be related to IR in addition to their identities as hemostasis markers during morbid obesity. Our findings have suggested that DONMA-lab index appears as the best surrogate marker for IR due to its discriminative feature between morbid obesity and MetS.

Keywords: children, insulin resistance, metabolic syndrome, plateletcrit, platelet indices

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5695 Dry Sliding Wear Behaviour of Ti3SiC2 and the Effect of TiC on Its

Authors: Bendaoudi Seif-Eddine, Bounazef Mokhtar

Abstract:

Wear behaviour of Ti3SiC2 coating in contact sliding under dry condition have been investigated on different pressures (0.1-0.8 MPa) at various speeds from 5 to 60 m/s. The ball-on-disc sliding-wear test was performed in ambient air with a relative humidity of 20%. An equation has been proposed to predict wear rates and describe sliding wear caused by Corundum ball on the studied material. The results show how the wear rate, measured by mass loss, varies in the range of (0.6 – 3.8 x E-6 mm3/Nm) with normal sliding distance under various test conditions; it increases with increasing load and rapidly with speed. The influence of TiC impurities on the wear behaviours was also investigated.

Keywords: ball-on-disc, dry-sliding, Ti3SiC2, wear

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5694 Power Production Performance of Different Wave Energy Converters in the Southwestern Black Sea

Authors: Ajab G. Majidi, Bilal Bingölbali, Adem Akpınar

Abstract:

This study aims to investigate the amount of energy (economic wave energy potential) that can be obtained from the existing wave energy converters in the high wave energy potential region of the Black Sea in terms of wave energy potential and their performance at different depths in the region. The data needed for this purpose were obtained using the calibrated nested layered SWAN wave modeling program version 41.01AB, which was forced with Climate Forecast System Reanalysis (CFSR) winds from 1979 to 2009. The wave dataset at a time interval of 2 hours was accumulated for a sub-grid domain for around Karaburun beach in Arnavutkoy, a district of Istanbul city. The annual sea state characteristic matrices for the five different depths along with a vertical line to the coastline were calculated for 31 years. According to the power matrices of different wave energy converter systems and characteristic matrices for each possible installation depth, the probability distribution tables of the specified mean wave period or wave energy period and significant wave height were calculated. Then, by using the relationship between these distribution tables, according to the present wave climate, the energy that the wave energy converter systems at each depth can produce was determined. Thus, the economically feasible potential of the relevant coastal zone was revealed, and the effect of different depths on energy converter systems is presented. The Oceantic at 50, 75 and 100 m depths and Oyster at 5 and 25 m depths presents the best performance. In the 31-year long period 1998 the most and 1989 is the least dynamic year.

Keywords: annual power production, Black Sea, efficiency, power production performance, wave energy converter

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5693 CAD Tool for Parametric Design modification of Yacht Hull Surface Models

Authors: Shahroz Khan, Erkan Gunpinar, Kemal Mart

Abstract:

Recently parametric design techniques became a vital concept in the field of Computer Aided Design (CAD), which helps to provide sophisticated platform to the designer in order to automate the design process in efficient time. In these techniques, design process starts by parameterizing the important features of design models (typically the key dimensions), with the implementation of design constraints. The design constraints help to retain the overall shape of the model while modifying its parameters. However, the process of initializing an appropriate number of design parameters and constraints is the crucial part of parametric design techniques, especially for complex surface models such as yacht hull. This paper introduces a method to create complex surface models in favor of parametric design techniques, a method to define the right number of parameters and respective design constraints, and a system to implement design parameters in contract to design constraints schema. For this, in our proposed approach the design process starts by dividing the yacht hull into three sections. Each section consists of different shape lines, which form the overall shape of yacht hull. The shape lines are created using Cubic Bezier Curves, which allow larger design flexibility. Design parameters and constraints are defined on the shape lines in 3D design space to facilitate the designers for better and individual handling of parameters. Afterwards, shape modifiers are developed, which allow the modification of each parameter while satisfying the respective set of criteria and design constraints. Such as, geometric continuities should be maintained between the shape lines of the three sections, fairness of the hull surfaces should be preserved after modification and while design modification, effect of a single parameter should be negligible on other parameters. The constraints are defined individually on shape lines of each section and mutually between the shape lines of two connecting sections. In order to validate and visualize design results of our shape modifiers, a real time graphic interface is created.

Keywords: design parameter, design constraints, shape modifies, yacht hull

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5692 Modeling Core Flooding Experiments for Co₂ Geological Storage Applications

Authors: Avinoam Rabinovich

Abstract:

CO₂ geological storage is a proven technology for reducing anthropogenic carbon emissions, which is paramount for achieving the ambitious net zero emissions goal. Core flooding experiments are an important step in any CO₂ storage project, allowing us to gain information on the flow of CO₂ and brine in the porous rock extracted from the reservoir. This information is important for understanding basic mechanisms related to CO₂ geological storage as well as for reservoir modeling, which is an integral part of a field project. In this work, a different method for constructing accurate models of CO₂-brine core flooding will be presented. Results for synthetic cases and real experiments will be shown and compared with numerical models to exhibit their predictive capabilities. Furthermore, the various mechanisms which impact the CO₂ distribution and trapping in the rock samples will be discussed, and examples from models and experiments will be provided. The new method entails solving an inverse problem to obtain a three-dimensional permeability distribution which, along with the relative permeability and capillary pressure functions, constitutes a model of the flow experiments. The model is more accurate when data from a number of experiments are combined to solve the inverse problem. This model can then be used to test various other injection flow rates and fluid fractions which have not been tested in experiments. The models can also be used to bridge the gap between small-scale capillary heterogeneity effects (sub-core and core scale) and large-scale (reservoir scale) effects, known as the upscaling problem.

Keywords: CO₂ geological storage, residual trapping, capillary heterogeneity, core flooding, CO₂-brine flow

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5691 Experimental Investigation of Bituminous Roads with Waste Plastic

Authors: Arjita Biswas, Sandeep Potnis

Abstract:

Plastic roads (bituminous roads using waste plastic in the wearing course ) have now become familiar in the Road Construction Sector in India. With the Indian Road Congress Code (IRC SP: 98 -2013), many agencies are coming forward to implement Plastic Roads in India. This paper discuss and compare about the various properties of bituminous mix with 8% waste plastic and normal bituminous mix. This paper also signifies the performance of both the types of roads after 4 months of age under loading conditions. Experiments were carried out to evaluate its performance. The result shows improved performance of plastic roads.

Keywords: bituminous roads, experiments, performance, plastic roads

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5690 Diversity and Distribution of Butterflies (Lepidoptera-Rhopalocera) along with Altitudinal Gradient and Vegetation Types at Lahoul Valley, Trans-Himalaya Region, India

Authors: Saveena Bogtapa, Jagbir Singh Kirti

Abstract:

Himalaya is one of the most fascinating ranges in the world. In India, it comprises 18 percent of the land area. Lahoul valley which is a part of Trans-Himalaya region is well known for its unique, diverse flora and fauna. It lies in the North-Eastern corner of the state Himachal Pradesh where its altitude ranges between 2500m to 5000m. Vegetation of this region is dry-temperate to alpine type. The diversity of the area is very less, rare, unique and highly endemic. But today, as a lot of environmental degradation has taken place in this hot spot of biodiversity because of frequent developmental and commercial activities which lead to the diversity of this area comes under a real threat. Therefore, as part of the research, butterflies which are known for their attractiveness as well as usefulness to the ecosystem, are used for the study. The diversity of butterflies of a particular area not only provides a healthy environment but also serves as the first step of conservation to the biodiversity. Their distribution in different habitats and altitude type helps us to understand the species richness and abundance in an area. Moreover, different environmental parameters which affect the butterfly community has also recorded. Hence, the present study documents the butterfly diversity in an unexplored habitat and altitude types at Lahoul valley. The valley has been surveyed along with altitudinal gradients (from 2500m to 4500m) and in various habitats like agriculture land, grassland, scrubland, riverine and in different types of forests. Very rare species of butterflies have been explored, and these will be discussed along with different parameters during the presentation.

Keywords: butterflies, diversity, Lahoul valley, altitude, vegetation

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5689 Scientific Expedition to Understand the Crucial Issues of Rapid Lake Expansion and Moraine Dam Instability Phenomena to Justify the Lake Lowering Effort of Imja Lake, Khumbu Region of Sagarmatha, Nepal

Authors: R. C. Tiwari, N. P. Bhandary, D. B. Thapa Chhetri, R. Yatabe

Abstract:

The research enlightens the various issues of lake expansion and stability of the moraine dam of Imja lake. The Imja lake considered that the world highest altitude lake (5010m from m.s.l.), located in the Khumbu, Sagarmatha region of Nepal (27.90 N and 86.90 E) was reported as one of the fast growing glacier lakes in the Nepal Himalaya. The research explores a common phenomenon of lake expansion and stability issues of moraine dam to justify the necessity of lake lowering efforts if any in future in other glacier lakes in Nepal Himalaya. For this, we have explored the root causes of rapid lake expansion along with crucial factors responsible for the stability of moraine mass. This research helps to understand the structure of moraine dam and the ice, water and moraine interactions to the strength of moraine dam. The nature of permafrost layer and its effects on moraine dam stability is also studied here. The detail Geo-Technical properties of moraine mass of Imja lake gives a clear picture of the strength of the moraine material and their interactions. The stability analysis of the moraine dam under the consideration of strong ground motion of 7.8Mw 2015 Barpak-Gorkha and its major aftershock 7.3Mw Kodari, Sindhupalchowk-Dolakha border, Nepal earthquakes have also been carried out here to understand the necessity of lake lowering efforts. The lake lowering effort was recently done by Nepal Army by constructing an open channel and lowered 3m. And, it is believed that the entire region is now safe due to continuous draining of lake water by 3m. But, this option does not seem adequate to offer a significant risk reduction to downstream communities in this much amount of volume and depth, lowering as in the 75 million cubic meter water impounded with an average depth of 148.9m.

Keywords: finite element method, glacier, moraine, stability

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5688 Evaluation of Percutaneous Tube Thoracostomy Performed by Trainee in Both Trauma and Non-Trauma Patients

Authors: Kulsum Maula, Md Kamrul Alam, Md Ibrahim Khalil, Md Nazmul Hasan, Mohammad Omar Faruq

Abstract:

Background: Percutaneous Tube Thoracostomy (PTT) is an invasive procedure that can save a life now and then in different traumatic and non-traumatic conditions. But still, it is an enigma; how our trainee surgeons are at home in this procedure. Objectives: To evaluate the outcome of the percutaneous tube thoracostomy performed by trainees in both trauma and non-trauma patients. Study design: Prospective, Observational Study. The duration of the study was September 2018 to February 2019. Methods: All patients who need PTT in traumatic and non-traumatic conditions were selected by purposive sampling. Thereafter, they were scrutinized according to eligibility criteria and 96 patients were finalized. A pre-tested, observation-based, peer-reviewed data collection sheet was prepared before the study. Data regarding clinical and surgical outcome profiles were recorded. Data were compiled, edited, and analyzed. Results: Among 96 patients, the highest 32.29% belonged to age group 31-40 years and the lowest 9.37% belonged to the age group ≤20. The mean age of the respondents was 29.19±9.81. We found out of 96 patients, 70(72.91%) were indicated PTT for traumatic conditions and the rest 26(27.08%) were indicated PTT for non-traumatic chest conditions, where 36(37.5%) had simple penumothorax, 21(21.87%) haemothorax, 14(14.58%) massive pleural effusion, 13(13.54%) tension pneumothorax, 10(10.41%) haemopneumothorax, and 2(2.08%) had pyothorax respectively. In 53.12% of patients had right-sided intercostal chest tube (ICT) insertion, whereas 46.87% had left-sided ICT insertion. In our study, 89.55 % of the tube was placed at the normal anatomical position. Besides, 10.41% of tube thoracostomy were performed deviated from anatomical site. Among 96 patients 62.5% patients had length of incision 2-3cm, 35.41% had >3cm and 2.08% had <2cm respectively. Out of 96 patients, 75(78.13%) showed uneventful outcomes, whereas 21(21.87%) had complications, including 11.15%(11) each had wound infection, 4.46%(4) subcutaneous emphysema, 4.28%(3) drain auto expulsion, 2.85%(2) hemorrhage, 1.45%(1) had a non-functioning drain and empyema with ascending infection respectively (p=<0.05). Conclusion: PTT is a life-saving procedure that is most frequently implemented in chest trauma patients in our country. In the majority of cases, the outcome of PTT was uneventful (78.13). Besides this, more than one-third of patients had a length of incision more than 3 cm that needed extra stitches and 10.41% of cases of PTT were placed other than the normal anatomical site. Trainees of Dhaka Medical College Hospitals are doing well in their performance of PTT insertion, but still, some anatomical orientations are necessary to avoid operative and post-operative complications.

Keywords: PTT, trainee, trauma, non-chest trauma patients

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5687 Analysis of Productivity and Poverty Status among Users of Improved Sorghum Varieties in Kano State, Nigeria

Authors: Temitope Adefunsho Olatoye, Julius Olabode Elega

Abstract:

Raising agricultural productivity is an important policy goal for governments and development agencies, and this is central to growth, income distribution, improved food security, and poverty alleviation among practitioners. This study analyzed the productivity and poverty status among users of improved sorghum varieties in Kano State, Nigeria. A multistage sampling technique was adopted in the selection of 131 sorghum farmers who were users of improved sorghum varieties. Data collected were analyzed using both descriptive (frequency distribution and percentage) and inferential (productivity index and FGT model) statistics. The result of the socioeconomic characteristics of the sorghum farmers showed a mean age of 40 years, with about 93.13% of the sorghum farmers being male. Also, as indicated by the result, the majority (82.44%) of the farmers were married, with most of them having qur’anic education with a mean farm size of 3.6 ha, as reported in the study area. Furthermore, the result showed that the mean farming experience of the sorghum farmers in the study area was 19 years, with an average monthly income of about ₦48,794, as reported in the study area. The result of the productivity index showed a ratio of 192,977kg/ha, while the result of poverty status shows that 62.88% were in the non-poor category, 21.21% were poor, and 15.91% were very poor, respectively. The result also showed that the incidence of poverty for sorghum farmers was 16%, indicating that the incidence of poverty was prevalent in the study area. Based on the findings of this study, it was therefore recommended that seed companies should facilitate the spread of improved sorghum varieties as it has an impact on the productivity and poverty status of sorghum farmers in the study area.

Keywords: Foster Greer Thorbecke model, improved sorghum varieties, productivity, poverty status

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5686 Analysis and Design of Irregular Large Cantilever Structure of Statue

Authors: Pan Rui, Ma Jun, Zhao Caiqi, Wang Guangda

Abstract:

With the development of the tourism and religion,more and more large statue structures are adopted to build all over the world.For instance,the GuanYin statue with three plane reaches 108 meters high in HaiNan province in China.These statue structures belong to typical high-rise Building. However,the geometry sculpt of statues are complicated .The irregular shape makes these structures more complicated in force analysis than those normal standard tall buildings.In this paper,the Liu Bang Statue which is located at XuZhou in China.

Keywords: large statue structure, special-shaped steel, GuanYin statue, China

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5685 Burnout and Salivary Cortisol Among Laboratory Personnel in Klang Valley, Malaysia During COVID-19 Pandemic

Authors: Maznieda Mahjom, Rohaida Ismail, Masita Arip, Mohd Shaiful Azlan, Nor’Ashikin Othman, Hafizah Abdullah, nor Zahrin Hasran, Joshita Jothimanickam, Syaqilah Shawaluddin, Nadia Mohamad, Raheel Nazakat, Tuan Mohd Amin, Mizanurfakhri Ghazali, Rosmanajihah Mat Lazim

Abstract:

COVID-19 outbreak is particularly detrimental to the mental health of everyone as well as leaving a long devastating crisis in the healthcare sector. Daily increment of COVID-19 cases and close contact, necessitating the testing of a large number of samples, thus increasing the workload and burden to laboratory personnel. This study aims to determine the prevalence of personal-, work- and client-related burnout as well as to measure the concentration of salivary cortisol among laboratory personnel in the main laboratories in Klang Valley, Malaysia. This cross-sectional study was conducted in late 2021 and recruited a total of 404 respondents from three laboratories in Klang Valley, Malaysia. The level of burnout was assessed using Copenhagen Burnout Inventory (CBI) comprising three sub-dimensions of personal-, work- and client-related burnout. The cut-off score of 50% and above indicated possible burnout. Meanwhile, salivary cortisol was measured using a competitive enzyme immunoassay kit (Salimetrics, State College, PA, USA). Normal levels of salivary cortisol concentration in adults are within 0.094 to 1.551 μg/dl (morning) and can be none detected to 0.359 μg/dl (evening). The prevalence of personal-, work- and client-related burnout among laboratory personnel were 36.1%, 17.8% and 7.2% respectively. Meanwhile, the abnormal morning and evening cortisol concentration recorded were 29.5% and 21.8% excluding 6.9%-7.4% missing data. While the IgA level is normal for most of the respondents, which recorded at 95.53%. Laboratory personnel were at risk of suffering burnout during the COVID-19 pandemic. Thus, mental health programs need to be addressed at the department and hospital level by regularly screening healthcare workers and designing an intervention program. It is also vital to improve the coping skills of laboratory personnel by increasing the awareness of good coping skill techniques. The training must be in an innovative way to ensure that the lab personnel can internalise the technique and practise it in real life.

Keywords: burnout, COVID-19, laborotary personnel, salivary cortisol

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5684 An Empirical Investigation of Uncertainty and the Lumpy Investment Channel of Monetary Policy

Authors: Min Fang, Jiaxi Yang

Abstract:

Monetary policy could be less effective at stimulating investment during periods of elevated volatility than during normal times. In this paper, we argue that elevated volatility leads to a decrease in extensive margin investment incentive so that nominal stimulus generates less aggregate investment. To do this, we first empirically document that high volatility weakens firms’ investment responses to monetary stimulus. Such effects depend on the lumpiness nature of the firm-level investment. The findings are that the channel exists for all of the physical investment, innovation investment, and organization investment.

Keywords: investment, irreversibility, volatility, uncertainty, firm heterogeneity, monetary policy

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5683 Sequence Polymorphism and Haplogroup Distribution of Mitochondrial DNA Control Regions HVS1 and HVS2 in a Southwestern Nigerian Population

Authors: Ogbonnaya O. Iroanya, Samson T. Fakorede, Osamudiamen J. Edosa, Hadiat A. Azeez

Abstract:

The human mitochondrial DNA (mtDNA) is about 17 kbp circular DNA fragments found within the mitochondria together with smaller fragments of 1200 bp known as the control region. Knowledge of variation within populations has been employed in forensic and molecular anthropology studies. The study was aimed at investigating the polymorphic nature of the two hypervariable segments (HVS) of the mtDNA, i.e., HVS1 and HVS2, and to determine the haplogroup distribution among individuals resident in Lagos, Southwestern Nigeria. Peripheral blood samples were obtained from sixty individuals who are not related maternally, followed by DNA extraction and amplification of the extracted DNA using primers specific for the regions under investigation. DNA amplicons were sequenced, and sequenced data were aligned and compared to the revised Cambridge Reference Sequence (rCRS) GenBank Accession number: NC_012920.1) using BioEdit software. Results obtained showed 61 and 52 polymorphic nucleotide positions for HVS1 and HVS2, respectively. While a total of three indels mutation were recorded for HVS1, there were seven for HVS2. Also, transition mutations predominate nucleotide change observed in the study. Genetic diversity (GD) values for HVS1 and HVS2 were estimated to be 84.21 and 90.4%, respectively, while random match probability was 0.17% for HVS1 and 0.89% for HVS2. The study also revealed mixed haplogroups specific to the African (L1-L3) and the Eurasians (U and H) lineages. New polymorphic sites obtained from the study are promising for human identification purposes.

Keywords: hypervariable region, indels, mitochondrial DNA, polymorphism, random match probability

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5682 Solanum Nigrum Show Anti-Obesity Effects on High Fat Diet Fed Sprague Dawley Rats

Authors: Kathryn Nderitu, Atunga Nyachieo, Ezekiel Mecha

Abstract:

Introduction: Solanum nigrum , also known as black nightshade, biosynthesizes various phytochemical compounds with various pharmacological activities, including treating cardiovascular diseases and type 2 diabetes, among others. Materials and Methods: To assess the anti-obesity effects of Solanum nigrum using high-fat-fed diet rats, Sprague Dawley male rats (n = 35) of weights 160–180 g were assigned randomly into seven groups comprising n = 5 rats each. Each group was fed for 11 weeks as follows: normal group (normal chow rat feed); high-fat diet control (HFD); HFD and standard drug (Orlistat 30 mg/kg bw); HFD and methanolic extract 150 mg/kgbw; HFD and methanolic extract 300 mg/kgbw; HFD and dichloromethane extract 150 mg/kgbw; HFD and dichloromethane extract 300 mg/kgbw. Body mass index and food intake were monitored per week, and an oral glucose tolerance test was measured in weeks 5 and 10. Lipid profiles, liver function tests, adipose tissue, liver weights, and phytochemical analysis of Solanum nigrum were later carried out. Results: High-fat diet control group rats exhibited a significant increase in body mass index (BMI), while rats administered with leaf extracts of Solanum nigrum showed a reduction in BMI. Both low doses of dichloromethane (150 mg/kgbw) and high doses of methanol extracts (300 mg/kgbw) showed a better reduction in BMI than the other treatment groups. A significant decrease (p <0.05) in low-density lipoprotein-cholesterol, triglycerides, and cholesterol was observed among the rats administered with Solanum nigrum extracts compared to those of HFD control. Moreover, the HFD control group significantly increased liver and adipose tissue weights compared to other treatment groups (p<0.05). Solanum nigrum also decreased glycemic levels and normalized the hepatic enzymes of HFD control. However, food intake among the groups showed no significant difference (p>0.05). Qualitative analysis of Solanum nigrum leaf extracts indicated the presence of various bioactive compounds associated with anti-obesity. Conclusion: These results validate the use of Solanum nigrum in controlling obesity.

Keywords: solanum nigrum, High fat diet, phytocompounds, obesity

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5681 Biaxial Fatigue Specimen Design and Testing Rig Development

Authors: Ahmed H. Elkholy

Abstract:

An elastic analysis is developed to obtain the distribution of stresses, strains, bending moment and deformation for a thin hollow, variable thickness cylindrical specimen when subjected to different biaxial loadings. The specimen was subjected to a combination of internal pressure, axial tensile loading and external pressure. Several axial to circumferential stress ratios were investigated in detail. The analytical model was then validated using experimental results obtained from a test rig using several biaxial loadings. Based on the preliminary results obtained, the specimen was then modified geometrically to ensure uniform strain distribution through its wall thickness and along its gauge length. The new design of the specimen has a higher buckling strength and a maximum value of equivalent stress according to the maximum distortion energy theory. A cyclic function generator of the standard servo-controlled, electro-hydraulic testing machine is used to generate a specific signal shape (sine, square,…) at a certain frequency. The two independent controllers of the electronic circuit cause an independent movement to each servo-valve piston. The movement of each piston pressurizes the upper and lower sides of the actuators alternately. So, the specimen will be subjected to axial and diametral loads independent of each other. The hydraulic system has two different pressures: one pressure will be responsible for axial stress produced in the specimen and the other will be responsible for the tangential stress. Changing the two pressure ratios will change the stress ratios accordingly. The only restriction on the maximum stress obtained is the capacity of the testing system and specimen instability due to buckling.

Keywords: biaxial, fatigue, stress, testing

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5680 Numerical Study on Response of Polymer Electrolyte Fuel Cell (PEFCs) with Defects under Different Load Conditions

Authors: Muhammad Faizan Chinannai, Jaeseung Lee, Mohamed Hassan Gundu, Hyunchul Ju

Abstract:

Fuel cell is known to be an effective renewable energy resource which is commercializing in the present era. It is really important to know about the improvement in performance even when the system faces some defects. This study was carried out to analyze the performance of the Polymer electrolyte fuel cell (PEFCs) under different operating conditions such as current density, relative humidity and Pt loadings considering defects with load changes. The purpose of this study is to analyze the response of the fuel cell system with defects in Balance of Plants (BOPs) and catalyst layer (CL) degradation by maintaining the coolant flow rate as such to preserve the cell temperature at the required level. Multi-Scale Simulation of 3D two-phase PEFC model with coolant was carried out under different load conditions. For detailed analysis and performance comparison, extensive contours of temperature, current density, water content, and relative humidity are provided. The simulation results of the different cases are compared with the reference data. Hence the response of the fuel cell stack with defects in BOP and CL degradations can be analyzed by the temperature difference between the coolant outlet and membrane electrode assembly. The results showed that the Failure of the humidifier increases High-Frequency Resistance (HFR), air flow defects and CL degradation results in the non-uniformity of current density distribution and high cathode activation overpotential, respectively.

Keywords: PEM fuel cell, fuel cell modeling, performance analysis, BOP components, current density distribution, degradation

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5679 Synthesis of Na-LSX Zeolite and Hydrosodalite from Polish Fly Ashes

Authors: Barbara Bialecka, Zdzislaw Adamczyk, Magdalena Cempa

Abstract:

In the work, the results of investigations into the hydrothermal zeolitization of fly ash from hard coal combustion in one of Polish Power Station have been presented. The chemical composition of the ash was determined by the method of X-ray fluorescence (XRF), whereas the phases of both fly ash and the products after synthesis were identified using microscopic observations, X-ray diffraction analysis (XRD) as well as electron scanning microscopy with measurements of the chemical compositions in micro areas (SEM/EDS). The synthesis was carried out with various concentrations of NaOH solution (3M, 4M and 6M) in the following conditions: synthesis temperature – 80ᵒC, synthesis time – 16 hours, volume of NaOH solution – 350ml, fly ash mass – 14g. The main chemical components of fly ash were SiO₂ and Al₂O₃, the contents of which reached 51.62 and 28.14%mas., respectively. The input ash contained mainly such phases as mullite, quarz, magnetite, and glass. The research results indicate that the phase composition of products after zeolitization was differentiated. The material after synthesis in 3M NaOH solution was found to contain mullite, quarz, magnetite, and Na-LSX zeolite. The products of synthesis in 4M NaOH solution were very similar to those in 3M solution (mullite, quarz, magnetite, Na-LSX zeolite), but they additionally contained hydrosodalite. The material after synthesis in 6M NaOH solution contains mullite, quarz, magnetite (similarly to synthesis in 3M and 4M NaOH solition) and additionally hydrosodalite. Therefore, the products of synthesis contain relic components from the fly ash input sample in the form of mullite, quarz, and magnetite, as well as new phases, which are Na-LSX zeolite and hydrosodalite. It should be noted that the products of synthesis in the case of 4M NaOH solution contained both new phases (Na-LSX zeolite and hydrosodalite), while the products from the extreme concentration of NaOH solutions (3M and 6M) contained only one of them. Observations in the scanning electron microscope revealed the new phases’ morphology. It was found that Na-LSX zeolite formed cubic crystals, whereas hydrosodalite formed characteristic aggregations. The results of investigations into the chemical composition in the micro area of phase grains in the products after synthesis reveal some dependencies, among others a characteristic increase in the content of sodium, related to the increased concentration of NaOH solution.

Keywords: Na-LSX, fly ash, hydrosodalite, zeolite

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