Search results for: composite section

Authors: Mairaj Salim, Asma Zaheer

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Oman has accomplished as much or more than its fellow Gulf monarchies, despite starting from scratch considerably later, having less oil income to utilize, dealing with a larger and more rugged geography, and resolving a bitter civil war along the way. Of course, Oman's progress in the past 30-plus years has not been without problems and missteps, but the balance is squarely on the positive side of the ledger. Oil has been the driving force of the Omani economy since Oman began commercial production in 1967. The oil industry supports the country’s high standard of living and is primarily responsible for its modern and expansive infrastructure, including electrical utilities, telephone services, roads, public education and medical services. In addition to extensive oil reserves, Oman also has substantial natural gas reserves, which are expected to play a leading role in the Omani economy in the Twenty-first Century. To reduce the country’s dependence on oil revenues, the government is restructuring the economy by directing investment to non-oil activities. Since the 21st century IT has changed the performing tasks. To manage the affairs for the benefits of organizations and economy, the Omani government has adopted E-Business technologies for the development. E-Business is important because it allows • Transformation of old economy relationships (vertical/linear relationships) to new economy relationships characterized by end-to-end relationship management solutions (integrated or extended relationships) • Facilitation and organization of networks, small firms depend on ‘partner’ firms for supplies and product distribution to meet customer demands • SMEs to outsource back-end process or cost centers enabling the SME to focus on their core competence • ICT to connect, manage and integrate processes internally and externally • SMEs to join networks and enter new markets, through shortened supply chains to increase market share, customers and suppliers • SMEs to take up the benefits of e-business to reduce costs, increase customer satisfaction, improve client referral and attract quality partners • New business models of collaboration for SMEs to increase their skill base • SMEs to enter virtual trading arena and increase their market reach A national strategy for the advancement of information and communication technology (ICT) has been worked out, mainly to introduce e-government, e-commerce, and a digital society. An information technology complex KOM (Knowledge Oasis Muscat) had been established, consisting of section for information technology, incubator services, a shopping center of technology software and hardware, ICT colleges, E-Government services and other relevant services. So, all these efforts play a vital role in the development of Oman economy.

Keywords: ICT, ITA, CRM, SCM, ERP, KOM, SMEs, e-commerce and e-business

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Authors: Neeraj Vij, Christian Leber, Kenneth Schmidt

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Introduction: Total knee arthroplasty is a common procedure. It is well known that the biomechanics of the knee do not fully return to their normal state. Motion analysis has been used to study the biomechanics of the knee after total knee arthroplasty. The purpose of this scoping review is to summarize the current use of gait analysis in total knee arthroplasty and to identify the preoperative motion analysis parameters for which a systematic review aimed at determining the reliability and validity may be warranted. Materials and Methods: This IRB-exempt scoping review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist strictly. Five search engines were searched for a total of 279 articles. Articles underwent a title and abstract screening process followed by full-text screening. Included articles were placed in the following sections: the role of gait analysis as a research tool for operative decisions, other research applications for motion analysis in total knee arthroplasty, gait analysis as a tool in predicting radiologic outcomes, gait analysis as a tool in predicting clinical outcomes. Results: Eleven articles studied gait analysis as a research tool in studying operative decisions. Motion analysis is currently used to study surgical approaches, surgical techniques, and implant choice. Five articles studied other research applications for motion analysis in total knee arthroplasty. Other research applications for motion analysis currently include studying the role of the unicompartmental knee arthroplasty and novel physical therapy protocols aimed at optimizing post-operative care. Two articles studied motion analysis as a tool for predicting radiographic outcomes. Preoperative gait analysis has identified parameters than can predict postoperative tibial component migration. 15 articles studied motion analysis in conjunction with clinical scores. Conclusions: There is a broad range of applications within the research domain of total knee arthroplasty. The potential application is likely larger. However, the current literature is limited by vague definitions of ‘gait analysis’ or ‘motion analysis’ and a limited number of articles with preoperative and postoperative functional and clinical measures. Knee adduction moment, knee adduction impulse, total knee range of motion, varus angle, cadence, stride length, and velocity have the potential for integration into composite clinical scores. A systematic review aimed at determining the validity, reliability, sensitivities, and specificities of these variables is warranted.

Keywords: motion analysis, joint replacement, patient-reported outcomes, knee surgery

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Authors: Lenuta Kloetzer, Alexandra C. Blaga, Dan Cascaval, Alexandra Tucaliuc, Anca I. Galaction

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Rosmarinic acid, an ester of caffeic acid and 3-(3,4-dihydroxyphenyl) lactic acid, is considered a valuable compound for the pharmaceutical and cosmetic industries due to its antimicrobial, antioxidant, antiviral, anti-allergic, and anti-inflammatory effects. It can be obtained by extraction from vegetable or animal materials, by chemical synthesis and biosynthesis. Indifferent of the method used for rosmarinic acid production, the separation and purification process implies high amount of raw materials and laborious stages leading to high cost for and limitations of the separation technology. This study focused on separation of rosmarinic acid by synergic reactive extraction with a mixture of two extractants, one acidic (acid di-(2ethylhexyl) phosphoric acid, D2EHPA) and one with basic character (Amberlite LA-2). The studies were performed in experimental equipment consisting of an extraction column where the phases’ mixing was made by mean of a perforated disk with 45 mm diameter and 20% free section, maintained at the initial contact interface between the aqueous and organic phases. The vibrations had a frequency of 50 s⁻¹ and 5 mm amplitude. The extraction was carried out in two solvents with different dielectric constants (n-heptane and dichloromethane) in which the extractants mixture of varying concentration was dissolved. The pH-value of initial aqueous solution was varied between 1 and 7. The efficiency of the studied extraction systems was quantified by distribution and synergic coefficients. For calculating these parameters, the rosmarinic acid concentration in the initial aqueous solution and in the raffinate have been measured by HPLC. The influences of extractants concentrations and solvent polarity on the efficiency of rosmarinic acid separation by synergic extraction with a mixture of Amberlite LA-2 and D2EHPA have been analyzed. In the reactive extraction system with a constant concentration of Amberlite LA-2 in the organic phase, the increase of D2EHPA concentration leads to decrease of the synergic coefficient. This is because the increase of D2EHPA concentration prevents the formation of amine adducts and, consequently, affects the hydrophobicity of the interfacial complex with rosmarinic acid. For these reasons, the diminution of synergic coefficient is more important for dichloromethane. By maintaining a constant value of D2EHPA concentration and increasing the concentration of Amberlite LA-2, the synergic coefficient could become higher than 1, its highest values being reached for n-heptane. Depending on the solvent polarity and D2EHPA amount in the solvent phase, the synergic effect is observed for Amberlite LA-2 concentrations over 20 g/l dissolved in n-heptane. Thus, by increasing the concentration of D2EHPA from 5 to 40 g/l, the minimum concentration value of Amberlite LA-2 corresponding to synergism increases from 20 to 40 g/l for the solvent with lower polarity, namely, n-heptane, while there is no synergic effect recorded for dichloromethane. By analysing the influences of the main factors (organic phase polarity, extractant concentration in the mixture) on the efficiency of synergic extraction of rosmarinic acid, the most important synergic effect was found to correspond to the extractants mixture containing 5 g/l D2EHPA and 40 g/l Amberlite LA-2 dissolved in n-heptane.

Keywords: Amberlite LA-2, di(2-ethylhexyl) phosphoric acid, rosmarinic acid, synergic effect

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Authors: Alexandru Achim, Tamás Szűcsborus, Viktor Sasi, Ferenc Nagy, Zoltán Jambrik, Attila Nemes, Albert Varga, Călin Homorodean, Olivier F. Bertrand, Zoltán Ruzsa

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Aim: Our study aimed to establish the safety and the technical success of distal radial access for balloon aortic valvuloplasty (DR-BAV). The secondary objective was to determine the effectiveness and appropriate role of DR-BAV within half year follow-up. Methods: Clinical and angiographic data from 32 consecutive patients with symptomatic aortic stenosis were evaluated in a prospective pilot single-center study. Between 2020 and 2021, the patients were treated utilizing dual distal radial access with 6-10F compatible balloons. The efficacy endpoint was divided into technical success (successful valvuloplasty balloon inflation at the aortic valve and absence of intra- or periprocedural major complications), hemodynamic success (a reduction of the mean invasive gradient >30%), and clinical success (an improvement of at least one clinical category in the NYHA classification). The safety endpoints were vascular complications (major and minor Valve Academic Research Consortium (VARC)-2 bleeding, diminished or lost arterial pulse or the presence of any pseudo-aneurysm or arteriovenous fistula during the clinical follow-up) and major adverse events, MAEs (the composite of death, stroke, myocardial infarction, and urgent major aortic valve replacement or implantation during the hospital stay and or at one-month follow-up). Results: 32 patients (40 % male, mean age 80 ± 8,5) with severe aortic valve stenosis were included in the study and 4 patients were excluded. Technical success was achieved in all patients (100%). Hemodynamic success was achieved in 30 patients (93,75%). Invasive max and mean gradients were reduced from 73±22 mm Hg and 49±22 mm Hg to 49±19 mm Hg and 20±13 mm Hg, respectively (p = <.001). Clinical success was achieved in 29 patients (90,6%). In total, no major adverse cardiac or cerebrovascular event nor vascular complications (according to VARC 2 criteria) occurred during the intervention. All-cause death at 6 months was 12%. Conclusion: According to our study, dual distal radial artery access is a safe and effective option for balloon aortic valvuloplasty in patients with severe aortic valve stenosis and can be performed in all patients with sufficient lumen diameter. Future randomized studies are warranted to investigate whether this technique is superior to other approaches.

Keywords: mean invasive gradient, distal radial access for balloon aortic valvuloplasty (DR-BAV), aortic valve stenosis, pseudo-aneurysm, arteriovenous fistula, valve academic research consortium (VARC)-2

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Authors: Mohammad R. Bhuyan, Mohammad J. Khattak

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Deterioration of flexible pavements due to crack reflection from its soil-cement base layer is a major concern around the globe. The service life of flexible pavement diminishes significantly because of the reflective cracks. Highway agencies are struggling for decades to prevent or mitigate these cracks in order to increase pavement service lives. The root cause of reflective cracks is the shrinkage crack which occurs in the soil-cement bases during the cement hydration process. The primary factor that causes the shrinkage is the cement content of the soil-cement mixture. With the increase of cement content, the soil-cement base gains strength and durability, which is necessary to withstand the traffic loads. But at the same time, higher cement content creates more shrinkage resulting in more reflective cracks in pavements. Historically, various states of USA have used the soil-cement bases for constructing flexile pavements. State of Louisiana (USA) had been using 8 to 10 percent of cement content to manufacture the soil-cement bases. Such traditional soil-cement bases yield 2.0 MPa (300 psi) 7-day compressive strength and are termed as cement stabilized design (CSD). As these CSD bases generate significant reflective cracks, another design of soil-cement base has been utilized by adding 4 to 6 percent of cement content called cement treated design (CTD), which yields 1.0 MPa (150 psi) 7-day compressive strength. The reduction of cement content in the CTD base is expected to minimize shrinkage cracks thus increasing pavement service lives. Hence, this research study evaluates the long-term field performance of CTD bases with respect to CSD bases used in flexible pavements. Pavement Management System of the state of Louisiana was utilized to select flexible pavement projects with CSD and CTD bases that had good historical record and time-series distress performance data. It should be noted that the state collects roughness and distress data for 1/10th mile section every 2-year period. In total, 120 CSD and CTD projects were analyzed in this research, where more than 145 miles (CTD) and 175 miles (CSD) of roadways data were accepted for performance evaluation and benefit-cost analyses. Here, the service life extension and area based on distress performance were considered as benefits. It was found that CTD bases increased 1 to 5 years of pavement service lives based on transverse cracking as compared to CSD bases. On the other hand, the service lives based on longitudinal and alligator cracking, rutting and roughness index remain the same. Hence, CTD bases provide some service life extension (2.6 years, on average) to the controlling distress; transverse cracking, but it was inexpensive due to its lesser cement content. Consequently, CTD bases become 20% more cost-effective than the traditional CSD bases, when both bases were compared by net benefit-cost ratio obtained from all distress types.

Keywords: cement treated base, cement stabilized base, reflective cracking , service life, flexible pavement

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Authors: Giovana Vesentini, Fernanda Piculo, Gabriela Marini, Debora Damasceno, Angelica Barbosa, Selma Martheus, Marilza Rudge

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Problem statement: Skeletal muscle is highly adaptable, muscle fiber composition and size can respond to a variety of stimuli, such physiologic, as pregnancy, and metabolic abnormalities, as Diabetes mellitus. This study aimed to analyze the effects of pregnancy-associated diabetes on the rectus abdominis muscle (RA), and to compare this changes in rats and women. Methods: Female Wistar rats were maintained under controlled conditions and distributed in Pregnant (P) and Long-term mild pregnant diabetic (LTMd) (n=3 r/group). Diabetes in rats was induced by streptozotocin (100mg/Kg, sc) on the first day of life, for a hyperglycemic state between 120-300 mg/dL in adult life. Female rats were mated overnight, at day 21 of pregnancy were anesthetized, and killed for the harvesting of maternal RA. Pregnant women who attended the Diabetes Prenatal Care Clinic of Botucatu Medical School were distributed in Pregnant non-diabetic (Pnd) and Gestational Diabetic (GDM) (n=3 w/group). The diagnosis of GDM was established according to ADA’s criteria (2016). The harvesting of RA was during the cesarean section. Transversal cross-sections of the RA of both women and rats were analyzed by transmission electron microscopy. All procedures were approved by the Ethics Committee on Animal Experiments of the Botucatu Medical School (Protocol Number 1003/2013) and by the Botucatu Medical School Ethical Committee for Human Research in Medical Sciences (CAAE: 41570815.0.0000.5411). Results: The photomicrographs of the RA of rats revealed disorganized Z lines, thinning sarcomeres, and a usual quantity of intermyofibrillar mitochondria in the P group. The LTMd group showed swollen sarcoplasmic reticulum, dilated T tubes and areas with sarcomere disruption. The ultrastructural analysis of Pnd non-diabetic women in the RA showed well-organized myofibrils forming intact sarcomeres, organized Z lines and a normal distribution of intermyofibrillar mitochondria. The GDM group revealed increase in intermyofibrillar mitochondria, areas with sarcomere disruption and increased lipid droplets. Conclusion: Pregnancy and diabetes induce adaptations in the ultrastructure of the rectus abdominis muscle for both women and rats, changing the architectural design of these tissues. However, in rats these changes are more severe maybe because, besides the high blood glucose levels, the quadrupedal animal may suffer an excessive mechanical tension during pregnancy by gravity. Probably, these findings may suggest that these alterations are a risk factor that contributes to the development of muscle dysfunction in women with GDM and may motivate treatment strategies in these patients.

Keywords: gestational diabetes, muscle dysfunction, pregnancy, rectus abdominis

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Authors: Soma Kanta Baral

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Background: Since 1981, when the first AIDS case was reported, worldwide, more than 34 million people have been infected with HIV. Almost 95 percent of the people infected with HIV live in developing countries. As HBV & HIV share similar routes of transmission by sexual intercourse or drug use by parenteral injection, co-infection is common. Because of the limited access to healthcare & HIV treatment in developing countries, HIV-infected individuals are present late for care. Enumeration of CD4+ T cell count at the time of diagnosis has been useful to initiate the therapy in HIV infected individuals. The baseline CD4+ T cell count shows high immunological variability among patients. Methods: This prospective study was done in the serology section of the Department of Microbiology over a period of one year from august 2012 to July 2013. A total of 13037 individuals subjected for HIV test were included in the study comprising of 4982 males & 8055 females. Blood sample was collected by vein puncture aseptically with standard operational procedure in clean & dry test-tube. All blood samples were screened for HIV as described by WHO algorithm by Immuno-chromatography rapid kits. Further confirmation was done by biokit ELISA method as per the manufacturer’s guidelines. After informed consent, HIV positive individuals were screened for HBsAg by Immuno-chromatography rapid kits (Hepacard). Further confirmation was done by biokit ELISA method as per the manufacturer’s guidelines. EDTA blood samples were collected from the HIV sero-positive individuals for baseline CD4+ T count. Then, CD4+ T cells count was determined by using FACS Calibur Flow Cytometer (BD). Results: Among 13037 individuals screened for HIV, 104 (0.8%) were found to be infected comprising of 69(66.34%) males & 35 (33.65%) females. The study showed that the high infection was noted in housewives (28.7%), active age group (30.76%), rural area (56.7%) & in heterosexual route (80.9%) of transmission. Out of total HIV infected individuals, distribution of HBV co-infection was found to be 6(5.7%). All co- infected individuals were married, male, above the age of 25 years & heterosexual route of transmission. Baseline CD4+ T cell count of HIV infected patient was found higher (mean CD4+ T cell count; 283cells/cu.mm) than HBV co-infected patients (mean CD4+ T cell count; 91 cells/cu.mm). Majority (77.2%) of HIV infected & all co-infected individuals were presented in our center late (CD4+ T cell count;< 350/cu. mm) for diagnosis and care. Majority of co- infected 4 (80%) were late presented with advanced AIDS stage (CD4+ count; <200/cu.mm). Conclusions: The study showed a high percentage of HIV sero-positive & co- infected individuals. Baseline CD4+ T cell count of majority of HIV infected individuals was found to be low. Hence, more sustained and vigorous awareness campaigns & counseling still need to be done in order to promote early diagnosis and management.

Keywords: HIV/AIDS, HBsAg, co-infection, CD4+

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Authors: Victoria Brennan, Andrea Mallaburn, Linda Seton

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Science outreach programmes connect school pupils with external agencies to provide activities and experiences that enhance their exposure to science. It can be argued that these programmes not only aim to support teachers with curriculum engagement and promote scientific literacy but also provide pivotal opportunities to spark scientific interest in students. In turn, a further objective of these programmes is to increase awareness of career opportunities within this field. Although outreach work is also often described as a fun and satisfying venture, a plethora of researchers express caution to how successful the processes are to increases engagement post-16 in science. When researching the impact of outreach programmes, it is often student feedback regarding the activities or enrolment numbers to particular science courses post-16, which are generated and analysed. Although this is informative, the longevity of the programme’s impact could be better informed by the teacher’s perceptions; the evidence of which is far more limited in the literature. In addition, there are strong suggestions that teachers can have an indirect impact on a student’s own self-concept. These themes shape the focus and importance of this ongoing research project as it presents the rationale that teachers are under-used resources when it comes to considering the design of science outreach programmes. Therefore, the end result of the research will consist of a presentation of an ‘optimum’ model of outreach. The result of which should be of interest to the wider stakeholders such as universities or private or government organisations who design science outreach programmes in the hope to recruit future scientists. During phase one, questionnaires (n=52) and interviews (n=8) have generated both quantitative and qualitative data. These have been analysed using the Wilcoxon non-parametric test to compare teachers’ perceptions of science outreach interventions and thematic analysis for open-ended questions. Both of these research activities provide an opportunity for a cross-section of teacher opinions of science outreach to be obtained across all educational levels. Therefore, an early draft of the ‘optimum’ model of science outreach delivery was generated using both the wealth of literature and primary data. This final (ongoing) phase aims to refine this model using teacher focus groups to provide constructive feedback about the proposed model. The analysis uses principles of modified Grounded Theory to ensure that focus group data is used to further strengthen the model. Therefore, this research uses a pragmatist approach as it aims to focus on the strengths of the different paradigms encountered to ensure the data collected will provide the most suitable information to create an improved model of sustainable outreach. The results discussed will focus on this ‘optimum’ model and teachers’ perceptions of benefits and drawbacks when it comes to engaging with science outreach work. Although the model is still a ‘work in progress’, it provides both insight into how teachers feel outreach delivery can be a sustainable intervention tool within the classroom and what providers of such programmes should consider when designing science outreach activities.

Keywords: educational partnerships, science education, science outreach, teachers

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Authors: Cemil Atakara, Hüseyin Eryaman

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The use of glass as an envelope of a building has been increasing in the twentieth century. For more transparency and dematerialization new glass facade types have emerged in the past two decades which depends on point fixed glazing system (PFGS). The aim of this study is to analyze of the PFGS systems which are used on the glass curtain wall according to their types, degree, architectural and structural effects. This new system is desired because it enhances the transparency of the façade and it minimizes the component of the frames or of the profiles. This PFGS led to new structural elements which use cables, rods, trusses when designing a glass building facades, this structural element called the suspended glass system with pre-stressed cable truss (SGSPCT) which has been used for the first time in 1980 in Serres building. The twenty glass buildings which are designed in different systems have been analyzed during this study. After these analyses five selected SGSPCT building analyzed deeply and one skeletal frame building selected from Lefkosa redesigned according to the analysis results. These selected buildings have been included of various cable-truss system typologies and degree. The methodology of this study is building analysis method and literature survey with the help of books, articles, magazines, drawings, internet sources and applied connection details of the glass buildings. The selected five glass buildings and case building have been detailed analyzed with their architectural drawings, photographs and details. A gridshell structure can be compared with a shell structure; it consists of discrete members connecting nodal points. As these nodal points lie on the surface of an imaginary shell, their shapes function almost identically. Difference between shell and gridshell structures can be found in the fact that, due to their free-form and thus, due to the presence of bending forces, gridshells are required to resist loading through their cross-section. This research is divided into parts. A general study about the glass building and cable-glass and grid shell system will be done in the first chapters. Structural analyses and detailed analyses with schematic drawings with the plans, sections of the selected buildings will be explained in the second part. The third part it consists of the advantages and disadvantages of the use of the SGSPCT and Grid Shell in architecture. The study consists of four chapters including the introduction chapter. The general information of the SGSPCT and glazing system has been mentioned in the first chapter. Structural features, typologies, transparency principle and analytical information on systems have been explained of the selected buildings in the second chapter. The detailed analyses of case building have been done according to their schematic drawings with the plans, sections in the third chapter. After third chapter SGSPCT discussed on to the case building and selected buildings. SGSPCT systems have been compared with their advantages and disadvantages to the other systems. Advantages of cable-truss systems and SGSPCT have been concluded that the use of glass substrates in the last chapter.

Keywords: cable truss, glass, grid shell, transparency

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Authors: George R. Puno, Eric N. Bruno

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The natural landscape of the Philippine archipelago plus the current realities of climate change make the country vulnerable to flood hazards. Flooding becomes the recurring natural disaster in the country resulting to lose of lives and properties. Musimusi is among the rivers which exhibited inundation particularly at the inhabited floodplain portion of its watershed. During the event, rescue operations and distribution of relief goods become a problem due to lack of high resolution flood maps to aid local government unit identify the most affected areas. In the attempt of minimizing impact of flooding, hydrologic modelling with high resolution mapping is becoming more challenging and important. This study focused on the analysis of flood extent as a function of different geomorphologic characteristics of Musimusi watershed. The methods include the delineation of morphometric parameters in the Musimusi watershed using Geographic Information System (GIS) and geometric calculations tools. Digital Terrain Model (DTM) as one of the derivatives of Light Detection and Ranging (LiDAR) technology was used to determine the extent of river inundation involving the application of Hydrologic Engineering Center-River Analysis System (HEC-RAS) and Hydrology Modelling System (HEC-HMS) models. The digital elevation model (DEM) from synthetic Aperture Radar (SAR) was used to delineate watershed boundary and river network. Datasets like mean sea level, river cross section, river stage, discharge and rainfall were also used as input parameters. Curve number (CN), vegetation, and soil properties were calibrated based on the existing condition of the site. Results showed that the drainage density value of the watershed is low which indicates that the basin is highly permeable subsoil and thick vegetative cover. The watershed’s elongation ratio value of 0.9 implies that the floodplain portion of the watershed is susceptible to flooding. The bifurcation ratio value of 2.1 indicates higher risk of flooding in localized areas of the watershed. The circularity ratio value (1.20) indicates that the basin is circular in shape, high discharge of runoff and low permeability of the subsoil condition. The heavy rainfall of 167 mm brought by Typhoon Seniang last December 29, 2014 was characterized as high intensity and long duration, with a return period of 100 years produced 316 m3s-1 outflows. Portion of the floodplain zone (1.52%) suffered inundation with 2.76 m depth at the maximum. The information generated in this study is helpful to the local disaster risk reduction management council in monitoring the affected sites for more appropriate decisions so that cost of rescue operations and relief goods distribution is minimized.

Keywords: flooding, geomorphology, mapping, watershed

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Authors: S. S. Sharma, P. R. Prabhu, K. Jagannath, Achutha Kini U., Gowri Shankar M. C.

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In present global scenario, aluminum alloys are coining the attention of many innovators as competing structural materials for automotive and space applications. Comparing to other challenging alloys, especially, 7xxx series aluminum alloys have been studied seriously because of their benefits such as moderate strength; better deforming characteristics, excellent chemical decay resistance, and affordable cost. 7075 Al-alloys have been used in the transportation industry for the fabrication of several types of automobile parts, such as wheel covers, panels and structures. It is expected that substitution of such aluminum alloys for steels will result in great improvements in energy economy, durability and recyclability. However, it is necessary to improve the strength and the formability levels at low temperatures in aluminium alloys for still better applications. Aluminum–Zinc–Magnesium with or without other wetting agent denoted as 7XXX series alloys are medium strength heat treatable alloys. Cu, Mn and Si are the other solute elements which contribute for the improvement in mechanical properties achievable by selecting and tailoring the suitable heat treatment process. On subjecting to suitable treatments like age hardening or cold deformation assisted heat treatments, known as low temperature thermomechanical treatments (LTMT) the challenging properties might be incorporated. T6 is the age hardening or precipitation hardening process with artificial aging cycle whereas T8 comprises of LTMT treatment aged artificially with X% cold deformation. When the cold deformation is provided after solution treatment, there is increase in hardness related properties such as wear resistance, yield and ultimate strength, toughness with the expense of ductility. During precipitation hardening both hardness and strength of the samples are increasing. Decreasing peak hardness value with increasing aging temperature is the well-known behavior of age hardenable alloys. The peak hardness value is further increasing when room temperature deformation is positively supported with age hardening known as thermomechanical treatment. Considering these aspects, it is intended to perform heat treatment and evaluate hardness, tensile strength, wear resistance and distribution pattern of reinforcement in the matrix. 2 to 2.5 and 3 to 3.5 times increase in hardness is reported in age hardening and LTMT treatments respectively as compared to as-cast composite. There was better distribution of reinforcements in the matrix, nearly two fold increase in strength levels and upto 5 times increase in wear resistance are also observed in the present study.

Keywords: reinforcement, precipitation, thermomechanical, dislocation, strain hardening

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Authors: Anukul K. Thakur, Ram Bilash Choudhary, Mandira Majumder

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In this technologically driven world, it is requisite to develop better, faster and smaller electronic devices for various applications to keep pace with fast developing modern life. In addition, it is also required to develop sustainable and clean sources of energy in this era where the environment is being threatened by pollution and its severe consequences. Supercapacitor has gained tremendous attention in the recent years because of its various attractive properties such as it is essentially maintenance-free, high specific power, high power density, excellent pulse charge/discharge characteristics, exhibiting a long cycle-life, require a very simple charging circuit and safe operation. Binary and ternary composites of conducting polymers with carbon and other layered transition metal dichalcogenides have shown tremendous progress in the last few decades. Compared with bulk conducting polymer, these days conducting polymers have gained more attention because of their high electrical conductivity, large surface area, short length for the ion transport and superior electrochemical activity. These properties make them very suitable for several energy storage applications. On the other hand, carbon materials have also been studied intensively, owing to its rich specific surface area, very light weight, excellent chemical-mechanical property and a wide range of the operating temperature. These have been extensively employed in the fabrication of carbon-based energy storage devices and also as an electrode material in supercapacitors. Incorporation of carbon materials into the polymers increases the electrical conductivity of the polymeric composite so formed due to high electrical conductivity, high surface area and interconnectivity of the carbon. Further, polymeric composites based on layered transition metal dichalcogenides such as molybdenum disulfide (MoS2) are also considered important because they are thin indirect band gap semiconductors with a band gap around 1.2 to 1.9eV. Amongst the various 2D materials, MoS2 has received much attention because of its unique structure consisting of a graphene-like hexagonal arrangement of Mo and S atoms stacked layer by layer to give S-Mo-S sandwiches with weak Van-der-Waal forces between them. It shows higher intrinsic fast ionic conductivity than oxides and higher theoretical capacitance than the graphite.

Keywords: supercapacitor, layered transition-metal dichalcogenide, conducting polymer, ternary, carbon

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Authors: Priyanka Dutta Chowdhury

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A globalized connected world, calling loud for a composite culture, was still not able to erase the pain of a desired nationalism based on cultural identity. In the South Asian region, the random drawing of the boundaries without taking the ethnic aspect into consideration have always challenged the very basis of the existence of certain groups. The urge to reunify with the fellow brothers on both sides of the border have always called for a chaos and schism in the countries of this region. Sometimes this became a tool to bargain with the state and find a favorable position in the power structure on the basis of cultural identity. In Pakistan and Afghanistan, the Pakhtuns who are divided across the border of the two countries, from the inception of creation of Pakistan have posed various challenges and hampered the growth of a consolidated nation. The Pakhtuns or Pashtuns of both Pakistan and Afghanistan have a strong cultural affinity which blurs their physical distancing and calls for a nationalism based on this ethnic affiliation. Both the sides wanted to create Pakhtunistan unifying all the Pakhtuns of the region. For long, this group have denied to accept the Durand line separating the two. This was an area of concern especially for the Pakhtuns of Pakistan torn between the decision either to join Afghanistan, create a nation of their own or be a part of Pakistan. This ethnic issue became a bone of contention between the two countries. Later, though well absorbed and recognized in the respective countries, they have fought for their identity and claimed for a dominant position in the politics of the nations. Because of the porous borders often influx of refugees was seen especially during Afghan Wars and later many extremists’ groups were born from them especially the Taliban. In the recent string of events, when the Taliban, who are mostly Pakhtuns ethnically, came in power in Afghanistan, a wave of sympathy arose in Pakistan. This gave a strengthening position to the religious Pakhtuns across the border. It is to be noted here that a fragmented Pakhtun identity between the religious and seculars were clearly visible, voicing for their place in the political hierarchy of the country with a vision distinct from each other especially in Pakistan. In this context the paper tries to evaluate the reasons for this cultural turmoil between the countries and this ethnic group. It also aims to analyze the concept of how the identity politics still holds its relevance in the contemporary world. Additionally, the recent trend of fragmented identity points towards instrumentalization of this ethnic groups, who are engaged in the bargaining process with the state for a robust position in the power structure. In the end, the paper aims to deduct from the theoretical conditions of identity politics, whether this is a primordial or a situational tool to have a visibility in the power structure of the contemporary world.

Keywords: cultural identity, identity politics, instrumentalization of identity pakhtuns, power structure

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Authors: Ayoola Adekunle Dada, Tolulope Omolola Fateropa

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There is no gain saying the fact that the Nigerian correctional services lack rehabilitation reformation. Owing to this, some so many inmates, including the female, become more emotionally bruised and hardened instead of coming out of the prison reformed. Although female inmates constitute only a small percentage worldwide, the challenges resulting from women falling under the provision of the penal system have prompted ficial and humanitarian bodies to consider female inmateas as vulnerable persons who need particular social work measures that meet their specific needs. Female inmates’condition may become worseinprisondue to the absence of the standard living condition. A survey of 100 female inmates will be used to determine the assessment of the living condition of the female inmates within the contexts in which they occur. Employing field methods from Medical Sociology and Law, the study seeks to make use of the collaboration of both disciplines for a comprehensive understanding of the scenario. Its specific objectives encompassed: (1) To examine access and use of health facilities among the female inmates;(2) To examine the effect of officers/warders attitude towards female inmates;(3)To investigate the perception of the female inmates towards the housing facilities in the centre and; (4) To investigate the feeding habit of the female inmates. Due to the exploratory nature of the study, the researchers will make use of mixed-method, such qualitative methods as interviews will be undertaken to complement survey research (quantitative). By adopting the above-explained inter-method triangulation, the study will not only ensure that the advantages of both methods are exploited but will also fulfil the basic purposes of research. The sampling for this study will be purposive. The study aims at sampling two correctional centres (Ado Ekiti and Akure) in order to generate representative data for the female inmates in South West Nigeria. In all, the total number of respondents will be 100. A cross-section of female inmates will be selected as respondents using a multi-stage sampling technique. 100 questionnaires will be administered. A semi structured (in-depth) interviews will be conducted among workers in the two selected correctional centres, respectively, to gain further insight on the living conditions of female inmates, which the survey may not readily elicit. These participants will be selected purposively in respect to their status in the organisation. Ethical issues in research on human subjects will be given due consideration. Such issues rest on principles of beneficence, non-maleficence, autonomy/justice and confidentiality. In the final analysis, qualitative data will be analyzed using manual content analysis. Both the descriptive and inferential statistics will be used for analytical purposes. Frequency, simple percentage, pie chart, bar chart, curve and cross-tabulations will form part of the descriptive analysis.

Keywords: assessment, health facilities, inmates, perception, living conditions

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Authors: J. T. Pitale, S. Ghassab, H. Ay, N. Berme

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Biomechanics researchers commonly use marker-based optical motion capture (MoCap) systems to extract human body kinematic data. These systems use cameras to detect passive or active markers placed on the subject. The cameras use triangulation methods to form images of the markers, which typically require each marker to be visible by at least two cameras simultaneously. Cameras in a conventional optical MoCap system are mounted at a distance from the subject, typically on walls, ceiling as well as fixed or adjustable frame structures. To accommodate for space constraints and as portable force measurement systems are getting popular, there is a need for smaller and smaller capture volumes. When the efficacy of a MoCap system is investigated, it is important to consider the tradeoff amongst the camera distance from subject, pixel density, and the field of view (FOV). If cameras are mounted relatively close to a subject, the area corresponding to each pixel reduces, thus increasing the image resolution. However, the cross section of the capture volume also decreases, causing reduction of the visible area. Due to this reduction, additional cameras may be required in such applications. On the other hand, mounting cameras relatively far from the subject increases the visible area but reduces the image quality. The goal of this study was to develop a quantitative methodology to investigate marker occlusions and optimize camera placement for a given capture volume and subject postures using three-dimension computer-aided design (CAD) tools. We modeled a 4.9m x 3.7m x 2.4m (LxWxH) MoCap volume and designed a mounting structure for cameras using SOLIDWORKS (Dassault Systems, MA, USA). The FOV was used to generate the capture volume for each camera placed on the structure. A human body model with configurable posture was placed at the center of the capture volume on CAD environment. We studied three postures; initial contact, mid-stance, and early swing. The human body CAD model was adjusted for each posture based on the range of joint angles. Markers were attached to the model to enable a full body capture. The cameras were placed around the capture volume at a maximum distance of 2.7m from the subject. We used the Camera View feature in SOLIDWORKS to generate images of the subject as seen by each camera and the number of markers visible to each camera was tabulated. The approach presented in this study provides a quantitative method to investigate the efficacy and efficiency of a MoCap camera setup. This approach enables optimization of a camera setup through adjusting the position and orientation of cameras on the CAD environment and quantifying marker visibility. It is also possible to compare different camera setup options on the same quantitative basis. The flexibility of the CAD environment enables accurate representation of the capture volume, including any objects that may cause obstructions between the subject and the cameras. With this approach, it is possible to compare different camera placement options to each other, as well as optimize a given camera setup based on quantitative results.

Keywords: motion capture, cameras, biomechanics, gait analysis

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Authors: Yau-Luen Ng, Nathan Banka, Santosh Devasia

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In this paper, a method based on soft artificial cilia is introduced to separate particles based on size and mass. In nature, cilia are used for fluid propulsion in the mammalian circulatory system, as well as for swimming and size-selective particle entrainment for feeding in microorganisms. Inspired by biological cilia, an array of artificial cilia was fabricated using Polydimethylsiloxane (PDMS) to simulate the actual motion. A row of four individually-controlled magnetic artificial cilia in a semi-circular channel are actuated by the magnetic fields from four permanent magnets. Each cilium is a slender rectangular cantilever approximately 13mm long made from a composite of PDMS and carbonyl iron particles. A time-varying magnetic force is achieved by periodically varying the out-of-plane distance from the permanent magnets to the cilia, resulting in large-amplitude deflections of the cilia that can be used to drive fluid motion. Previous results have shown that this system of individually-controlled magnetic cilia can generate effective mixing flows; the purpose of the present work is to apply the individual cilia control to a particle separation task. Based on the observed beating patterns of cilia arrays in nature, the experimental beating patterns were selected as a metachronal wave, in which a fixed phase lead or lag is imposed between adjacent cilia. Additionally, the beating frequency was varied. For each set of experimental parameters, the channel was filled with water and polyethylene microspheres introduced at the center of the cilia array. Two types of particles were used: large red microspheres with density 0.9971 g/cm³ and 850-1000 μm avg. diameter, and small blue microspheres with density 1.06 g/cm³ and diameter 30 μm. At low beating frequencies, all particles were propelled in the mean flow direction. However, the large particles were observed to reverse directions above about 4.8 Hz, whereas reversal of the small particle transport direction did not occur until 6 Hz. Between these two transition frequencies, the large and small particles can be separated as they move in opposite directions. The experimental results show that selecting an appropriate cilia beating pattern can lead to selective transport of neutrally-buoyant particles based on their size. Importantly, the separation threshold can be chosen dynamically by adjusting the actuation frequency. However, further study is required to determine the range of particle sizes that can be effectively separated for a given system geometry.

Keywords: magnetic cilia, particle separation, tunable separation, soft actutors

Procedia PDF Downloads 199

Authors: Angela T. H. Kwan, Saman Arfaie, Joseph Therriault, Zahra Azizi, Firoza Z. Lussier, Cecile Tissot, Mira Chamoun, Gleb Bezgin, Stijn Servaes, Jenna Stevenon, Nesrine Rahmouni, Vanessa Pallen, Serge Gauthier, Pedro Rosa-Neto

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Alzheimer’s disease (AD) can be detected in living people using in vivo biomarkers of amyloid-β (Aβ) and tau, even in the absence of cognitive impairment during the preclinical phase. [¹⁸F]-MK-6420 is a high affinity positron emission tomography (PET) tracer that quantifies tau neurofibrillary tangles, but its ability to predict cognitive changes associated with early AD symptoms, such as memory decline, is unclear. Here, we assess the prognostic accuracy of baseline [18F]-MK-6420 tau PET for predicting longitudinal memory decline in asymptomatic elderly individuals. In a longitudinal observational study, we evaluated a cohort of cognitively normal elderly participants (n = 111) from the Translational Biomarkers in Aging and Dementia (TRIAD) study (data collected between October 2017 and July 2020, with a follow-up period of 12 months). All participants underwent tau PET with [¹⁸F]-MK-6420 and Aβ PET with [¹⁸F]-AZD-4694. The exclusion criteria included the presence of head trauma, stroke, or other neurological disorders. There were 111 eligible participants who were chosen based on the availability of Aβ PET, tau PET, magnetic resonance imaging (MRI), and APOEε4 genotyping. Among these participants, the mean (SD) age was 70.1 (8.6) years; 20 (18%) were tau PET positive, and 71 of 111 (63.9%) were women. A significant association between baseline Braak I-II [¹⁸F]-MK-6240 SUVR positivity and change in composite memory score was observed at the 12-month follow-up, after correcting for age, sex, and years of education (Logical Memory and RAVLT, standardized beta = -0.52 (-0.82-0.21), p < 0.001, for dichotomized tau PET and -1.22 (-1.84-(-0.61)), p < 0.0001, for continuous tau PET). Moderate cognitive decline was observed for A+T+ over the follow-up period, whereas no significant change was observed for A-T+, A+T-, and A-T-, though it should be noted that the A-T+ group was small.Our results indicate that baseline tau neurofibrillary tangle pathology is associated with longitudinal changes in memory function, supporting the use of [¹⁸F]-MK-6420 PET to predict the likelihood of asymptomatic elderly individuals experiencing future memory decline. Overall, [¹⁸F]-MK-6420 PET is a promising tool for predicting memory decline in older adults without cognitive impairment at baseline. This is of critical relevance as the field is shifting towards a biological model of AD defined by the aggregation of pathologic tau. Therefore, early detection of tau pathology using [¹⁸F]-MK-6420 PET provides us with the hope that living patients with AD may be diagnosed during the preclinical phase before it is too late.

Keywords: alzheimer’s disease, braak I-II, in vivo biomarkers, memory, PET, tau

Procedia PDF Downloads 76

Authors: Lorena C. Cintra, Izadora M. De Oliveira, Amanda G. Fernandes, Francieli Colussi, Rosália S. A. Jesuíno, Fabrícia P. Faria, Cirano J. Ulhoa

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Xylan is the main component of hemicellulose and for its complete degradation is required cooperative action of a system consisting of several enzymes including endo-xylanases (XYN), β-xylosidases (XYL) and α-L-arabinofuranosidases (ABF). The recombinant hemicellulolytic enzymes an endoxylanase (HXYN2), β-xylosidase (HXYLA), and an α-L-arabinofuranosidase (ABF3) were used in hydrolysis tests. These three enzymes are produced by filamentous fungi and were expressed heterologously and produced in Pichia pastoris previously. The aim of this work was to evaluate the effect of recombinant hemicellulolytic enzymes on the enzymatic hydrolysis of sugarcane bagasse (SCB). The interaction between the three recombinant enzymes during SCB pre-treated by steam explosion hydrolysis was performed with different concentrations of HXYN2, HXYLA and ABF3 in different ratios in according to a central composite rotational design (CCRD) 23, including six axial points and six central points, totaling 20 assays. The influence of the factors was assessed by analyzing the main effects and interaction between the factors, calculated using Statistica 8.0 software (StatSoft Inc. Tulsa, OK, USA). The Pareto chart was constructed with this software and showed the values of the Student’s t test for each recombinant enzyme. It was considered as response variable the quantification of reducing sugars by DNS (mg/mL). The Pareto chart showed that the recombinant enzyme ABF3 exerted more significant effect during SCB hydrolysis, with higher concentrations and with the lowest concentration of this enzyme. It was performed analysis of variance according to Fisher method (ANOVA). In ANOVA for the release of reducing sugars (mg/ml) as the variable response, the concentration of ABF3 showed significance during hydrolysis SCB. The result obtained by ANOVA, is in accordance with those presented in the analysis method based on the statistical Student's t (Pareto chart). The degradation of the central chain of xylan by HXYN2 and HXYLA was more strongly influenced by ABF3 action. A model was obtained, and it describes the performance of the interaction of all three enzymes for the release of reducing sugars, and can be used to better explain the results of the statistical analysis. The formulation capable of releasing the higher levels of reducing sugars had the following concentrations: HXYN2 with 600 U/g of substrate, HXYLA with 11.5 U.g-1 and ABF3 with 0.32 U.g-1. In conclusion, the recombinant enzyme that has a more significant effect during SCB hydrolysis was ABF3. It is noteworthy that the xylan present in the SCB is arabinoglucoronoxylan, due to this fact debranching enzymes are important to allow access of enzymes that act on the central chain.

Keywords: experimental design, hydrolysis, recombinant enzymes, sugar cane bagasse

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Authors: A. D'Alessandro, F. Ubertini, A. L. Materazzi

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In the field of civil engineering, Structural Health Monitoring is a topic of growing interest. Effective monitoring instruments permit the control of the working conditions of structures and infrastructures, through the identification of behavioral anomalies due to incipient damages, especially in areas of high environmental hazards as earthquakes. While traditional sensors can be applied only in a limited number of points, providing a partial information for a structural diagnosis, novel transducers may allow a diffuse sensing. Thanks to the new tools and materials provided by nanotechnology, new types of multifunctional sensors are developing in the scientific panorama. In particular, cement-matrix composite materials capable of diagnosing their own state of strain and tension, could be originated by the addition of specific conductive nanofillers. Because of the nature of the material they are made of, these new cementitious nano-modified transducers can be inserted within the concrete elements, transforming the same structures in sets of widespread sensors. This paper is aimed at presenting the results of a research about a new self-sensing nanocomposite and about the implementation of smart sensors for Structural Health Monitoring. The developed nanocomposite has been obtained by inserting multi walled carbon nanotubes within a cementitious matrix. The insertion of such conductive carbon nanofillers provides the base material with piezoresistive characteristics and peculiar sensitivity to mechanical modifications. The self-sensing ability is achieved by correlating the variation of the external stress or strain with the variation of some electrical properties, such as the electrical resistance or conductivity. Through the measurement of such electrical characteristics, the performance and the working conditions of an element or a structure can be monitored. Among conductive carbon nanofillers, carbon nanotubes seem to be particularly promising for the realization of self-sensing cement-matrix materials. Some issues related to the nanofiller dispersion or to the influence of the nano-inclusions amount in the cement matrix need to be carefully investigated: the strain sensitivity of the resulting sensors is influenced by such factors. This work analyzes the dispersion of the carbon nanofillers, the physical properties of the fresh dough, the electrical properties of the hardened composites and the sensing properties of the realized sensors. The experimental campaign focuses specifically on their dynamic characterization and their applicability to the monitoring of full-scale elements. The results of the electromechanical tests with both slow varying and dynamic loads show that the developed nanocomposite sensors can be effectively used for the health monitoring of structures.

Keywords: carbon nanotubes, self-sensing nanocomposites, smart cement-matrix sensors, structural health monitoring

Procedia PDF Downloads 227

Authors: Chaitanya H. Acharya, Pavan Kumar P., Gopalakrishna Narayana

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In the realm of aerodynamics, numerous vehicles incorporate moving components to enhance their performance. For instance, airliners deploy hydraulically operated flaps and ailerons during take-off and landing, while Formula 1 racing cars utilize hydraulic tubes and actuators for various components, including the Drag Reduction System (DRS). The DRS, consisting of a rear wing and adjustable flaps, plays a crucial role in overtaking manoeuvres. The DRS has two positions: the default position with the flaps down, providing high downforce, and the lifted position, which reduces drag, allowing for increased speed and aiding in overtaking. Swift deployment of the DRS during races is essential for overtaking competitors. The fluid flow over the rear wing flap becomes intricate during deployment, involving flow reversal and operational changes, leading to unsteady flow physics that significantly influence aerodynamic characteristics. Understanding the drag and downforce during DRS deployment is crucial for determining race outcomes. While experiments can yield accurate aerodynamic data, they can be expensive and challenging to conduct across varying speeds. Computational Fluid Dynamics (CFD) emerges as a cost-effective solution to predict drag and downforce across a range of speeds, especially with the rapid deployment of the DRS. This study employs the finite volume-based solver Ansys Fluent, incorporating dynamic mesh motions and a turbulent model to capture the complex flow phenomena associated with the moving rear wing flap. A dedicated section for the rare wing-flap is considered in the present simulations, and the aerodynamics of these sections closely resemble S1223 aerofoils. Before delving into the simulations of the rare wing-flap aerofoil, numerical results undergo validation using experimental data from an NLR flap aerofoil case, encompassing different flap angles at two distinct angles of attack was carried out. The increase in flap angle as increase in lift and drag is observed for a given angle of attack. The simulation methodology for the rare-wing-flap aerofoil case involves specific time durations before lifting the flap. During this period, drag and downforce values are determined as 330 N and 1800N, respectively. Following the flap lift, a noteworthy reduction in drag to 55 % and a decrease in downforce to 17 % are observed. This understanding is critical for making instantaneous decisions regarding the deployment of the Drag Reduction System (DRS) at specific speeds, thereby influencing the overall performance of the Formula 1 racing car. Hence, this work emphasizes the utilization of dynamic mesh motion methodology to predict the aerodynamic characteristics during the deployment of the DRS in a Formula 1 racing car.

Keywords: DRS, CFD, drag, downforce, dynamics mesh motion

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Authors: Shilpa Sahoo, Michel Louge, Anthony Reeves, Olivier Desjardins, Susan Daniel, Sadik Omowunmi

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The microgravity on the International Space Station (ISS) was exploited to study the imbibition of water into a network of hydrophilic cylindrical capillaries on time and length scales long enough to observe details hitherto inaccessible under Earth gravity. When a drop touches a porous medium, it spreads as if laid on a composite surface. The surface first behaves as a hydrophobic material, as liquid must penetrate pores filled with air. When contact is established, some of the liquid is drawn into pores by a capillarity that is resisted by viscous forces growing with length of the imbibed region. This process always begins with an inertial regime that is complicated by possible contact pinning. To study imbibition on Earth, time and distance must be shrunk to mitigate gravity-induced distortion. These small scales make it impossible to observe the inertial and pinning processes in detail. Instead, in the International Space Station (ISS), astronaut Luca Parmitano slowly extruded water spheres until they touched any of nine capillary plates. The 12mm diameter droplets were large enough for high-speed GX1050C video cameras on top and side to visualize details near individual capillaries, and long enough to observe dynamics of the entire imbibition process. To investigate the role of contact pinning, a text matrix was produced which consisted nine kinds of porous capillary plates made of gold-coated brass treated with Self-Assembled Monolayers (SAM) that fixed advancing and receding contact angles to known values. In the ISS, long-term microgravity allowed unambiguous observations of the role of contact line pinning during the inertial phase of imbibition. The high-speed videos of spreading and imbibition on the porous plates were analyzed using computer vision software to calculate the radius of the droplet contact patch with the plate and height of the droplet vs time. These observations are compared with numerical simulations and with data that we obtained at the ESA ZARM free-fall tower in Bremen with a unique mechanism producing relatively large water spheres and similarity in the results were observed. The data obtained from the ISS can be used as a benchmark for further numerical simulations in the field.

Keywords: droplet imbibition, hydrophilic surface, inertial phase, porous medium

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Authors: Lana Damaj, Vincent Laur, Azar Maalouf, Alexis Chevalier

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Matched termination is an important part of the passive waveguide components. It is typically used at the end of a waveguide transmission line to prevent reflections and improve signal quality. Waveguide terminations (loads) are commonly used in microwave and RF applications. In traditional microwave architectures, usually, waveguide termination consists of a standard rectangular waveguide made by a lossy resistive material, and ended by shorting metallic plate. These types of terminations are used, to dissipate the energy as heat. However, these terminations may increase the size and the weight of the overall system. New alternative solution consists in developing terminations based on 3D-printing of materials. Designing such terminations is very challenging since it should meet the requirements imposed by the system. These requirements include many parameters such as the absorption, the power handling capability in addition to the cost, the size and the weight that have to be minimized. 3D-printing is a shaping process that enables the production of complex geometries. It allows to find best compromise between requirements. In this paper, a comparison study has been made between different existing and new shapes of waveguide terminations. Indeed, 3D printing of absorbers makes it possible to study not only standard shapes (wedge, pyramid, tongue) but also more complex topologies such as exponential ones. These shapes have been designed and simulated using CST MWS®. The loads have been printed using the carbon-filled PolyLactic Acid, conductive PLA from ProtoPasta. Since the terminations has been characterized in the X-band (from 8GHz to 12GHz), the rectangular waveguide standard WR-90 has been selected. The classical wedge shape has been used as a reference. First, all loads have been simulated with the same length and two parameters have been compared: the absorption level (level of |S11|) and the dissipated power density. This study shows that the concave exponential pyramidal shape has the better absorption level and the convex exponential pyramidal shape has the better dissipated power density level. These two loads have been printed in order to measure their properties. A good agreement between the simulated and measured reflection coefficient has been obtained. Furthermore, a study of material structuring based on the honeycomb hexagonal structure has been investigated in order to vary the effective properties. In the final paper, the detailed methodology and the simulated and measured results will be presented in order to show how 3D-printing can allow controlling mass, weight, absorption level and power behaviour.

Keywords: additive manufacturing, electromagnetic composite materials, microwave measurements, passive components, power handling capacity (PHC), 3D-printing

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Authors: Belen Montero, Carmen Ramirez, Maite Rico, Rebeca Bouza, Irene Derungs

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Starch is a promising polymer for producing biocomposite materials because it is renewable, completely biodegradable and easily available at a low cost. Thermoplastic starches (TPS) can be obtained after the disruption and plasticization of native starch with a plasticizer. In this work, the solvent casting method was used to obtain TPS films from wheat starch plasticized with glycerol and reinforced with nanocellulose (CNC). X-ray diffraction analysis was used to follow the evolution of the crystallinity. The native wheat starch granules have shown a profile corresponding to A-type crystal structures typical for cereal starches. When TPS films are analyzed a high amorphous halo centered on 19º is obtained, indicating the plasticization process is completed. SEM imaging was made in order to analyse the morphology. The image from the raw wheat starch granules shows a bimodal granule size distribution with some granules in large round disk-shape forms (A-type) and the others as smaller spherical particles (B-type). The image from the neat TPS surface shows a continuous surface. No starch aggregates or swollen granules can be seen so, the plasticization process is complete. In the surfaces of reinforced TPS films aggregates are seen as the CNC concentration in the matrix increases. The CNC influence on the mechanical properties of TPS films has been studied by dynamic mechanical analysis. A direct relation exists between the storage modulus values, E’, and the CNC content in reinforced TPS films: higher is the content of nanocellulose in the composite, higher is the value of E’. This reinforcement effect can be explained by the appearance of a strong and crystalline nanoparticle-TPS interphase. Thermal stability of films was analysed by TGA. It has not observed any influence on the behaviour related to the thermal degradation of films with the incorporation of the CNC. Finally, the resistance to the water absorption films was analysed following the standard UNE-EN ISO 1998:483. The percentage of water absorbed by the samples at each time was calculated. The addition of 5 wt % of CNC to the TPS matrix leads to a significant improvement in the moisture resistance of the starch based material decreasing their diffusivity. It has been associated to the formation of a nanocrystal network that prevents swelling of the starch and therefore water absorption and to the high crystallinity of cellulose compared to starch. As a conclusion, the wheat film reinforced with 5 wt % of cellulose nanocrystals seems to be a good alternative for short-life applications into the packaging industry, because of its greatest rigidity, thermal stability and moisture sorption resistance.

Keywords: biocomposites, nanocellulose, starch, wheat

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Authors: Vibha Devi, Shabina Khanam

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Hemp (Cannabis sativa) possesses a rich content of ω-6 linoleic and ω-3 linolenic essential fatty acid in the ratio of 3:1, which is a rare and most desired ratio that enhances the quality of hemp oil. These components are beneficial for the development of cell and body growth, strengthen the immune system, possess anti-inflammatory action, lowering the risk of heart problem owing to its anti-clotting property and a remedy for arthritis and various disorders. The present study employs supercritical fluid extraction (SFE) approach on hemp seed at various conditions of parameters; temperature (40 - 80) °C, pressure (200 - 350) bar, flow rate (5 - 15) g/min, particle size (0.430 - 1.015) mm and amount of co-solvent (0 - 10) % of solvent flow rate through central composite design (CCD). CCD suggested 32 sets of experiments, which was carried out. As SFE process includes large number of variables, the present study recommends the application of resampling techniques for cross-validation of the obtained data. Cross-validation refits the model on each data to achieve the information regarding the error, variability, deviation etc. Bootstrap and jackknife are the most popular resampling techniques, which create a large number of data through resampling from the original dataset and analyze these data to check the validity of the obtained data. Jackknife resampling is based on the eliminating one observation from the original sample of size N without replacement. For jackknife resampling, the sample size is 31 (eliminating one observation), which is repeated by 32 times. Bootstrap is the frequently used statistical approach for estimating the sampling distribution of an estimator by resampling with replacement from the original sample. For bootstrap resampling, the sample size is 32, which was repeated by 100 times. Estimands for these resampling techniques are considered as mean, standard deviation, variation coefficient and standard error of the mean. For ω-6 linoleic acid concentration, mean value was approx. 58.5 for both resampling methods, which is the average (central value) of the sample mean of all data points. Similarly, for ω-3 linoleic acid concentration, mean was observed as 22.5 through both resampling. Variance exhibits the spread out of the data from its mean. Greater value of variance exhibits the large range of output data, which is 18 for ω-6 linoleic acid (ranging from 48.85 to 63.66 %) and 6 for ω-3 linoleic acid (ranging from 16.71 to 26.2 %). Further, low value of standard deviation (approx. 1 %), low standard error of the mean (< 0.8) and low variance coefficient (< 0.2) reflect the accuracy of the sample for prediction. All the estimator value of variance coefficients, standard deviation and standard error of the mean are found within the 95 % of confidence interval.

Keywords: resampling, supercritical fluid extraction, hemp oil, cross-validation

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Authors: Kaushiki Sanyal, Rajesh Chakrabarti

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In India, on average, about 60 Bills are passed every year in both Houses of Parliament – Lok Sabha and Rajya Sabha (calculated from information on websites of both Houses). These are debated in both Lok Sabha (House of Commons) and Rajya Sabha (Council of States) before they are passed. However, lawmakers rarely use empirical evidence to make a case for a law. Most of the time, they support a law on the basis of anecdote, intuition, and common sense. While these do play a role in law-making, without the necessary empirical evidence, laws often fail to achieve their desired results. The quality of legislative debates is an indicator of the efficacy of the legislative process through which a Bill is enacted. However, the study of legislative debates has not received much attention either in India or worldwide due to the difficulty of objectively measuring the quality of a debate. Broadly, three approaches have emerged in the study of legislative debates. The rational-choice or formal approach shows that speeches vary based on different institutional arrangements, intra-party politics, and the political culture of a country. The discourse approach focuses on the underlying rules and conventions and how they impact the content of the debates. The deliberative approach posits that legislative speech can be reasoned, respectful, and informed. This paper aims to (a) develop a framework to judge the quality of debates by using the deliberative approach; (b) examine the legislative debates of three Bills passed in different periods as a demonstration of the framework, and (c) examine the broader structural issues that disincentive MPs from scrutinizing Bills. The framework would include qualitative and quantitative indicators to judge a debate. The idea is that the framework would provide useful insights into the legislators’ knowledge of the subject, the depth of their scrutiny of Bills, and their inclination toward evidence-based research. The three Bills that the paper plans to examine are as follows: 1. The Narcotics Drugs and Psychotropic Substances Act, 1985: This act was passed to curb drug trafficking and abuse. However, it mostly failed to fulfill its purpose. Consequently, it was amended thrice but without much impact on the ground. 2. The Criminal Laws (Amendment) Act, 2013: This act amended the Indian Penal Code to add a section on human trafficking. The purpose was to curb trafficking and penalise traffickers, pimps, and middlemen. However, the crime rate remains high while the conviction rate is low. 3. The Surrogacy (Regulation) Act, 2021: This act bans commercial surrogacy allowing only relatives to act as surrogates as long as there is no monetary payment. Experts fear that instead of preventing commercial surrogacy, it would drive the activity underground. The consequences would be borne by the surrogate, who would not be protected by law. The purpose of the paper is to objectively analyse the quality of parliamentary debates, get insights into how MPs understand the evidence and deliberate on steps to incentivise them to use empirical evidence.

Keywords: legislature, debates, empirical, India

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Authors: Gabriel Acha Ekobi

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Fathers play a crucial role in meeting family needs such as affection, protection, and socio-economic needs of children in the world in general and South Africa in particular. Fathers’ role in children’s lives is important in providing socialization, leadership skills, and teaching societal norms. Fathers influence is very significant for children’s well-being and development as it provides the child with moral lessons, guidance, and economic support. However, there is a paucity of information regarding the effects of fathers on children. In addition, despite legal frameworks such as the African Charter on the Rights and Welfare of the child (1999) introduced by the African Union to promote child rights nevertheless, it appears maltreatment, abuse, and poor health care continue to face children. Also, the Constitution of 1996 of the Republic of South Africa (Section 28 of the Bill of Rights) and the Children’s Act 38 of 2005 were introduced by the South African government to foster the rights of children. Nevertheless, these legal frameworks remain ineffective as children’s rights are still neglected by resident fathers. This paper explores the impact of resident fathers on children in the Golf View, Alice town of the Eastern Cape Province, South Africa. A qualitative research method and an exploratory research design were utilized, and 30 participants took part in the study. The participants comprised of single mothers or caregivers of children, resident fathers and social workers. Eighteen (18) single mothers or caregivers, 10 resident fathers, and two (2) social workers participated in the study. Data was collected using semi-structured and unstructured interviews and analysed thematically. Two main themes were identified: the role of fathers on children and the effects of resident fathers on children. The study found that the presence of fathers in the lives of children prevented psychosocial issues such as stress, depression, violence, and substance abuse. A father’s presence in a household was crucial in instilling moral values in children. This allowed them to build positive characters such as respect, kindness, humility, and compassion. Children with more involved fathers tend to have fewer impulse control problems, longer attention spans, and a higher level of sociability. The study concludes that the fathers’ role prevented anxiety, depression, and stress and led to the improvement of children’s education performance. Nevertheless, the absence of a father as a role model to act as a leader by instilling moral values hinders positive behaviours in children. This study recommended that occupational training and life skills programmes should be introduced by the government and other stakeholders to empower the fathers as this might provide the platform for them to bring up their children properly.

Keywords: children, fathering, household, resident, single parent

Procedia PDF Downloads 52

Authors: Priyanka Gupta, Nilanjana Bairagi, Deepti Gupta

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New pathogenic strains of microbes are continually emerging and resistance of bacteria to antibiotics is growing. Hospitals in India have a high burden of infections in their intensive care units and general wards. Rising incidence of hospital infections is a matter of great concern in India. This growth is often attributed to the absence of effective infection control strategies in healthcare facilities. Government, therefore, is looking for cost effective strategies that are effective against HAIs. One possible method is by application of an antimicrobial finish on the uniform. But there are limited studies to show the effect of antimicrobial activity of antimicrobial finish treated nurses’ uniforms in a real hospital set up. This paper proposes a prospective non-destructive sampling technique, based on the use of a detachable fabric patch, to assess the effectiveness of silver based antimicrobial agent across five wards in a tertiary care government hospital in Delhi, India. Fabrics like polyester and polyester cotton blend fabric which are more prevalent for making coats were selected for the study. Polyester and polyester cotton blend fabric was treated with silver based antimicrobial (AM) finish. At the beginning of shift, a composite patch of untreated and treated fabric respectively was stitched on the abdominal region on the left and right side of the washed white coat of participating nurse. At the end of the shift, the patch was removed and taken for bacterial sampling on Brain Heart Infusion (BHI) plates. Microbial contamination on polyester and blend fabrics after 6 hours shift was compared in Brain Heart Infusion broth (BHI). All patches treated with silver based antimicrobial agent showed decreased bacterial counts. Percent reduction in the bacterial colonies after the antimicrobial treatment in both fabrics was 81.0 %. Antimicrobial finish was equally effective in reducing microbial adhesion on both fabric types. White coats of nurses become progressively contaminated during clinical care. Type of fabric used to make the coat can affect the extent of contamination which is higher on polyester cotton blend as compared to 100% polyester. The study highlights the importance of silver based antimicrobial finish in the area of uniform hygiene. Bacterial load can be reduced by using antimicrobial finish on hospital uniforms. Hospital staff uniforms endowed with antimicrobial properties may be of great help in reducing the occurrence and spread of infections.

Keywords: antimicrobial finish, bacteria, infection control, silver, white coat

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Authors: Ladda Thiamwong, Renata Komalasari

Abstract:

Falls are the leading cause of disability and hospitalization in low-income older adults. Fear of falling is present in 20% to 85 % of older adults and has been identified as an independent risk factor of fall risk, activity restriction, and loss of independence. About 12% of American older adults have subjective cognitive decline. Cognitive impairment is also an established factor of fall risk. However, it is unclear whether measures of fear of falling and subjective cognitive decline have the greatest association with fall risk in low-income older adults. The aim of this study was to evaluate the association between fear of falling, subjective cognitive decline-functional performance (SCD-FP), and fall risk using simple screening tools. In this cross-section study, we collected data from community-dwelling older adults 60 years or older in low-income settings in Central Florida, and 86 participants were included in the data analysis. Fear of falling was assessed by the Short Fall Efficacy Scale- International (Short FES-I) with seven items. Subjective cognitive decline-functional performance (SCD-FP) was assessed by a self-reported experience of worsening or more frequent confusion or memory loss in the past 12 months and its functional implications. Fall risk was evaluated by the Centers for Disease Control and Prevention (CDC)'s Stay Independent checklist with 12 items. The majority of participants were female, and more than half of the participants were African American. More than half of the participants had a higher school degree or higher, and less than 20% had no financial problems. Less than 30% of the participants perceived their general health as very good- excellent. More than half of the participants lived alone, and less than 15% lived with a partner or spouse. About 60% of the participants had hypertension, 40% had diabetes, 16% had cancer, and 50% had arthritis. About 30% of the participants had difficulty walking up ten steps without resting, more than 40% felt unsteady when walking, and 30% had been advised to use a cane or walker to get around safely. Regression analysis showed that fall risk was associated with fear of falling ( = .524, p <.001) and subjective cognitive decline-functional performance ( = .465, p =.027). The structure coefficient showed that fear of falling (rs2 = .922) was a stronger predictor of fall risk than subjective cognitive decline-functional performance (rs2= .200). Fear of falling and subjective cognitive decline-functional performance are growing public health issues, and addressing those issues is a public priority. Proactive screening for fear of falling and subjective cognitive decline-functional performance is critical in fall prevention. A combination of all three self-reported tools (Short FES-I, SCD-FP, and CDC's Stay Independent checklist) takes less than 5 minutes to complete. Primary care providers or public health professionals should consider including these tools to screen fear of falling and subjective cognitive decline-functional performance as part of fall risk assessment, especially in low-income settings. Thus, encouraging older adults and healthcare professionals to discuss fear of falling, subjective cognitive decline, and fall risk during routine medical office visits.

Keywords: falls, fall risk, fear of falling, cognition, subjective cognitive decline, low-income, older adults, community, screening, nursing, primary care

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Authors: Gaëtan Calvar, Christophe Bouvier, Alexis Blasselle

Abstract:

This paper presents the Sea Striker, a compact hydrofoil designed with the goal to address some of the issues raised by the recent evolutions of naval missions, threats and operation theatres in modern warfare. Able to perform a wide range of operations, the Sea Striker is a 40-meter stealth surface combatant equipped with a gas turbine and aft and forward foils to reach high speeds. The Sea Striker's stealthiness is enabled by the combination of composite structure, exterior design, and the advanced integration of sensors. The ship is fitted with a powerful and adaptable combat system, ensuring a versatile and efficient response to modern threats. Lightly Manned with a core crew of 10, this hydrofoil is highly automated and can be remoted pilote for special force operation or transit. Such a kind of ship is not new: it has been used in the past by different navies, for example, by the US Navy with the USS Pegasus. Nevertheless, the recent evolutions in science and technologies on the one hand, and the emergence of new missions, threats and operation theatres, on the other hand, put forward its concept as an answer to nowadays operational challenges. Indeed, even if multiples opinions and analyses can be given regarding the modern warfare and naval surface operations, general observations and tendencies can be drawn such as the major increase in the sensors and weapons types and ranges and, more generally, capacities; the emergence of new versatile and evolving threats and enemies, such as asymmetric groups, swarm drones or hypersonic missile; or the growing number of operation theatres located in more coastal and shallow waters. These researches were performed with a complete study of the ship after several operational performance computations in order to justify the relevance of using ships like the Sea Striker in naval surface operations. For the selected scenarios, the conception process enabled to measure the performance, namely a “Measure of Efficiency” in the NATO framework for 2 different kinds of models: A centralized, classic model, using large and powerful ships; and A distributed model relying on several Sea Strikers. After this stage, a was performed. Lethal, agile, stealth, compact and fitted with a complete set of sensors, the Sea Striker is a new major player in modern warfare and constitutes a very attractive response between the naval unit and the combat helicopter, enabling to reach high operational performances at a reduced cost.

Keywords: surface combatant, compact, hydrofoil, stealth, velocity, lethal

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Authors: V. Samulionis, J. Banys, A. Sánchez-Ferrer

Abstract:

Inorganic nanoparticles are used for fabrication of various composites based on polymer materials because they exhibit a good homogeneity and solubility of the composite material. Multifunctional materials based on composites of a polymer containing inorganic nanotubes are expected to have a great impact on industrial applications in the future. An emerging family of such composites are polyurea elastomers with inorganic MoS2 nanotubes or MoSI nanowires. Polyurea elastomers are a new kind of materials with higher performance than polyurethanes. The improvement of mechanical, chemical and thermal properties is due to the presence of hydrogen bonds between the urea motives which can be erased at high temperature softening the elastomeric network. Such materials are the combination of amorphous polymers above glass transition and crosslinkers which keep the chains into a single macromolecule. Polyurea exhibits a phase separated structure with rigid urea domains (hard domains) embedded in a matrix of flexible polymer chains (soft domains). The elastic properties of polyurea can be tuned over a broad range by varying the molecular weight of the components, the relative amount of hard and soft domains, and concentration of nanoparticles. Ultrasonic methods as non-destructive techniques can be used for elastomer composites characterization. In this manner, we have studied the temperature dependencies of the longitudinal ultrasonic velocity and ultrasonic attenuation of these new polyurea elastomers and composites with inorganic nanoparticles. It was shown that in these polyurea elastomers large ultrasonic attenuation peak and corresponding velocity dispersion exists at 10 MHz frequency below room temperature and this behaviour is related to glass transition Tg of the soft segments in the polymer matrix. The relaxation parameters and Tg depend on the segmental molecular weight of the polymer chains between crosslinking points, the nature of the crosslinkers in the network and content of MoS2 nanotubes or MoSI nanowires. The increase of ultrasonic velocity in composites modified by nanoparticles has been observed, showing the reinforcement of the elastomer. In semicrystalline polyurea elastomer matrices, above glass transition, the first order phase transition from quasi-crystalline to the amorphous state has been observed. In this case, the sharp ultrasonic velocity and attenuation anomalies were observed near the transition temperature TC. Ultrasonic attenuation maximum related to glass transition was reduced in quasicrystalline polyureas indicating less influence of soft domains below TC. The first order phase transition in semicrystalline polyurea elastomer samples has large temperature hysteresis (> 10 K). The impact of inorganic MoS2 nanotubes resulted in the decrease of the first order phase transition temperature in semicrystalline composites.

Keywords: inorganic nanotubes, polyurea elastomer composites, ultrasonic velocity, ultrasonic attenuation

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