Search results for: sustained loading.

Authors: K. Nikovics, D. Riccobono, M. Oger, H. Morin, L. Barbier, T. Poyot, X. Holy, A. Bendahmane, M. Drouet, A. L. Favier

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Muscle regeneration after injury (as irradiation) is of great importance. However, the molecular and cellular mechanisms are still unclear. Cytokines are believed to play fundamental role in the different stages of muscle regeneration. They are secreted by many cell populations, but the predominant producers are macrophages and helper T cells. On the other hand, it has been shown that adipose tissue derived stromal/stem cell (ASC) injection could improve muscle regeneration. Stem cells probably induce the coordinated modulations of gene expression in different macrophage cells. Therefore, we investigated the patterns and timing of changes in gene expression of different cytokines occurring upon stem cells loading. Muscle regeneration was studied in an irradiated muscle of minipig animal model in presence or absence of ASC treatment (irradiated and treated with ASCs, IRR+ASC; irradiated not-treated with ASCs, IRR; and non-irradiated no-IRR). We characterized macrophage populations by immunolabeling in the different conditions. In our study, we found mostly M2 and a few M1 macrophages in the IRR+ASC samples. However, only few M2b macrophages were noticed in the IRR muscles. In addition, we found intensive fibrosis in the IRR samples. With in situ hybridization and immunolabeling, we analyzed the cytokine expression of the different macrophages and we showed that M2d macrophage are the most abundant in the IRR+ASC samples. By in situ hybridization, strong expression of the transforming growth factor β (TGF-β) was observed in the IRR+ASC but very week in the IRR samples. But when we analyzed TGF-β level with immunolabeling the expression was very different: many M2 macrophages showed week expression in IRR+ASC and few cells expressing stronger level in IRR muscles. Therefore, we investigated the MMP expressions in the different muscles. Our data showed that the M2 macrophages of the IRR+ASC muscle expressed MMP2 proteins. Our working hypothesis is that MMP2 expression of the M2 macrophages can decrease fibrosis in the IRR+ASC muscle by capturing TGF-β.

Keywords: adipose tissue derived stromal/stem cell, cytokine, macrophage, muscle regeneration

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Authors: Hanan Algarni

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Background: Impairment of walking and balance skills has negative impact on functional independence and community participation after stroke. Gait recovery is considered a primary goal in rehabilitation by both patients and physiotherapists. Treadmill training coupled with virtual reality technology is a new emerging approach that offers patients with feedback, open and random skills practice while walking and interacting with virtual environmental scenes. Objectives: To synthesize the evidence around the effects of the VR treadmill training on gait speed and balance primarily, functional independence and community participation secondarily in stroke patients. Methods: Systematic review was conducted; search strategy included electronic data bases: MEDLINE, AMED, Cochrane, CINAHL, EMBASE, PEDro, Web of Science, and unpublished literature. Inclusion criteria: Participant: adult >18 years, stroke, ambulatory, without severe visual or cognitive impartments. Intervention: VR treadmill training alone or with physiotherapy. Comparator: any other interventions. Outcomes: gait speed, balance, function, community participation. Characteristics of included studies were extracted for analysis. Risk of bias assessment was performed using Cochrane's ROB tool. Narrative synthesis of findings was undertaken and summary of findings in each outcome was reported using GRADEpro. Results: Four studies were included involving 84 stroke participants with chronic hemiparesis. Interventions intensity ranged (6-12 sessions, 20 minutes-1 hour/session). Three studies investigated the effects on gait speed and balance. 2 studies investigated functional outcomes and one study assessed community participation. ROB assessment showed 50% unclear risk of selection bias and 25% of unclear risk of detection bias across the studies. Heterogeneity was identified in the intervention effects at post training and follow up. Outcome measures, training intensity and durations also varied across the studies, grade of evidence was low for balance, moderate for speed and function outcomes, and high for community participation. However, it is important to note that grading was done on few numbers of studies in each outcome. Conclusions: The summary of findings suggests positive and statistically significant effects (p<0.05) of VR treadmill training compared to other interventions on gait speed, dynamic balance skills, function and participation directly after training. However, the effects were not sustained at follow up in two studies (2 weeks-1 month) and other studies did not perform follow up measurements. More RCTs with larger sample sizes and higher methodological quality are required to examine the long term effects of VR treadmill effects on function independence and community participation after stroke, in order to draw conclusions and produce stronger robust evidence.

Keywords: virtual reality, treadmill, stroke, gait rehabilitation

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Authors: Rachmat Mauludin, Novita R. Kusuma, Diky Mudhakir

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Famotidine (FMT) is one of used substances in the treatment of hiperacidity and peptic ulcer, administered orally and parenterally via intravenous injection. Oral administration, which is more favorable, has been reported to have many obstacles in the process of the treatment, includes decreasing the bioavailability of FMT. This research was aimed to prepare FMT in form of solid lipid nanoparticles (SLN) with size ranging between 100-200 nm. The research was carried out also by optimizing factors that may affect physical stability of SLN. Formulation of Famotidine SLN was carried out by optimizing factors, such as duration of homogenization and sonication, lipid concentration, stabilizer composition and stabilizer concentration. SLN physical stability was evaluated (particle size distribution) for 42 days in 3 diferent temperatures. Entrapment efficiency and drug loading was determined indirectly and directly. The morphology of SLN was visualized by transmission electron microscope (TEM). In vitro release study of FMT was conducted in 2 mediums, at pH of 1.2 and 7.4. Chemical stability of FMT was determined by quantifying the concentration of FMT within 42 days. Famotidin SLN consisted of GMS as lipid and poloxamer 188, lecithin, and polysorbate 80 as stabilizers. Homogenization and sonication was performed for 5 minutes and 10 minutes. Physyical stability of nanoparticles at 3 different temperatures was no significant difference. The best formula was physically stable until 42 days with mean particle size below 200 nm. Nanoparticles produced was able to entrap FMT until 86.6%. Evaluation by TEM showed that nanoparticles was spherical and solid. In medium pH of 1.2, FMT was released only 30% during 4 hour. On the other hand, within 4 hours SLN could release FMT completely in medium pH of 7.4. The FMT concentration in nanoparticles dispersion was maintained until 95% in 42 days (40oC, RH 75%). Famotidine SLN was able to be produced with mean particle size ranging between 100-200 nm and physically stable for 42 days. SLN could be loaded by 86,6% of FMT. Morphologically, obtained SLN was spheric and solid. During 4 hours in medium pH of 1.2 and 7.4, FMT was released until 30% and 100%, respectively.

Keywords: solid lipid nanoparticle (SLN), famotidine (FMT), physicochemical properties, release study

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Authors: Nagui A. Abdel-Khalek, Khaled A. Selim, Ahmed Hamdy

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Kaolin is naturally occurring ore predominantly containing kaolinite mineral in addition to some gangue minerals. Typical impurities present in kaolin ore are quartz, iron oxides, titanoferrous minerals, mica, feldspar, organic matter, etc. The main coloring impurity, particularly in the ultrafine size range, is titanoferrous minerals. Kaolin is used in many industrial applications such as sanitary ware, table ware, ceramic, paint, and paper industries, each of which should be of certain specifications. For most industrial applications, kaolin should be processed to obtain refined clay so as to match with standard specifications. For example, kaolin used in paper and paint industries need to be of high brightness and low yellowness. Egyptian kaolin is not subjected to any beneficiation process and the Egyptian companies apply selective mining followed by, in some localities, crushing and size reduction only. Such low quality kaolin can be used in refractory and pottery production but not in white ware and paper industries. This paper aims to study the amenability of beneficiation of an Egyptian kaolin ore of El-Teih locality, Sinai, to be suitable for different industrial applications. Attrition scrubbing and classification followed by magnetic separation are applied to remove the associated impurities. Attrition scrubbing and classification are used to separate the coarse silica and feldspars. Wet high intensity magnetic separation was applied to remove colored contaminants such as iron oxide and titanium oxide. Different variables affecting of magnetic separation process such as solid percent, magnetic field, matrix loading capacity, and retention time are studied. The results indicated that substantial decrease in iron oxide (from 1.69% to 0.61% ) and TiO2 (from 3.1% to 0.83%) contents as well as improving iso-brightness (from 63.76% to 75.21% and whiteness (from 79.85% to 86.72%) of the product can be achieved.

Keywords: Kaolin, titanoferrous minerals, beneficiation, magnetic separation, attrition scrubbing, classification

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Authors: Moen Torill, Rismark Marit, Astrid M. Solvberg

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In Norway, every municipality shall provide an educational psychological service, EPS, to support kindergartens and schools in their work with children and youths with special needs. The EPS focus its work on individuals, aiming to identify special needs and to give advice to teachers and parents when they ask for it. In addition, the service also give priority to prevention and system intervention in kindergartens and schools. To master these big tasks university courses are established to support EPS counsellors' continuous learning. There is, however, a need for more in-depth and systematic knowledge on how they experience the courses they attend. In this study, EPS counsellors’ reflection logs during a particular course are investigated. The research question is: what are the content and priorities of the reflections that are communicated in the logs produced by the educational psychological counsellors during a post-graduate course? The investigated course is a credit course organized over a one-year period in two one-semester modules. The altogether 55 students enrolled in the course work as EPS counsellors in various municipalities across Norway. At the end of each day throughout the course period, the participants wrote reflection logs about what they had experienced during the day. The data material consists of 165 pages of typed text. The collaborating researchers studied the data material to ascertain, differentiate and understand the meaning of the content in each log. The analysis also involved the search for similarity in content and development of analytical categories that described the focus and primary concerns in each of the written logs. This involved constant 'critical and sustained discussions' for mutual construction of meaning between the co-researchers in the developing categories. The process is inspired by Grounded Theory. This means that the concepts developed during the analysis derived from the data material and not chosen prior to the investigation. The analysis revealed that the concept 'Useful' frequently appeared in the participants’ reflections and, as such, 'Useful' serves as a core category. The core category is described through three major categories: (1) knowledge sharing (concerning direct and indirect work with students with special needs) with colleagues is useful, (2) reflections on models and theoretical concepts (concerning students with special needs) are useful, (3) reflection on the role as EPS counsellor is useful. In all the categories, the notion of useful occurs in the participants’ emphasis on and acknowledgement of the immediate and direct link between the university course content and their daily work practice. Even if each category has an importance and value of its own, it is crucial that they are understood in connection with one another and as interwoven. It is the connectedness that gives the core category an overarching explanatory power. The knowledge from this study may be a relevant contribution when it comes to designing new courses that support continuing professional development for EPS counsellors, whether for post-graduate university courses or local courses at the EPS offices or whether in Norway or other countries in the world.

Keywords: constructing and circulating knowledge, educational-psychological counsellor, higher education, professional development

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Authors: E. Faizan, Wahab Abdul Ghafar, Tao Zhong

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Steel plate shear walls (SPSWs) are a robust lateral load resistance structure because of their high flexibility and efficient energy dissipation when subjected to seismic loads. This research investigates the seismic performance of an innovative infill web strip (IWS-SPSW) and a typical unstiffened steel plate shear wall (USPSW). As a result, two 1:3 scale specimens of an IWS-SPSW and USPSW with a single story and a single bay were built and subjected to a cyclic lateral loading methodology. In the prototype, the beam-to-column connections were accomplished with the assistance of semi-rigid end-plate connectors. IWS-SPSW demonstrated exceptional ductility and shear load-bearing capacity during the testing process, with no cracks or other damage occurring. In addition, the IWS-SPSW could effectively dissipate energy without causing a significant amount of beam-column connection distortion. The shear load-bearing capacity of the USPSW was exceptional. However, it exhibited low ductility, severe infill plate corner ripping, and huge infill web plate cracks. The FE models were created and then confirmed using the experimental data. It has been demonstrated that the infill web strips of an SPSW system can affect the system's high performance and total energy dissipation. In addition, a parametric analysis was carried out to evaluate the material qualities of the IWS, which can considerably improve the system's seismic performances. These properties include the steel's strength as well as its thickness.

Keywords: steel shear walls, seismic performance, failure mode, hysteresis response, nonlinear finite element analysis, parametric study

Procedia PDF Downloads 56

Authors: Ferruh Taspinar, Ismail Saracoglu, Emrah Afsar, Eda O. Okur, Gulce K. Seyyar, Gamze Kurt, Betul Taspinar

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Although it is thought that abdominal adiposity is one of the risk factor for postural deviation, such as increased lumbar lordosis, the body mass index is not sufficient to indicate effects of abdominal adiposity on spinal alignment and postural changes. The aim of this study was to investigate the correlation with detailed body composition and spine alignment in healthy young adults. This cross-sectional study was conducted with sixty seven healthy volunteers (37 men and 30 women) whose ages ranged between 19 and 27 years. All participants’ sagittal spinal curvatures of lumbar and thoracic region were measured via Spinal mouse® (Idiag, Fehraltorf, Switzerland). Also, body composition analysis (whole body fat ratio, whole body muscle ratio, abdominal fat ratio, and trunk muscle ratio) estimation by means of bioelectrical impedance was evaluated via Tanita Bc 418 Ma Segmental Body Composition Analyser (Tanita, Japan). Pearson’s correlation was used to analysis among the variables. The mean lumbar lordosis and thoracic kyphosis angles were 21.02°±9.39, 41.50°±7.97, respectively. Statistically analysis showed a significant positive correlation between whole body fat ratio and lumbar lordosis angle (r=0.28, p=0.02). Similarly, there was a positive correlation between abdominal fat ratio and lumbar lordosis angle (r=0.27, p=0.03). The thoracic kyphosis angle showed also positive correlation with whole body fat ratio (r=0.33, p=0.00) and abdominal fat ratio (r=0.40, p=0.01). The whole body muscle ratio showed negative correlation between lumbar lordosis (r=-0.28, p=0.02) and thoracic kyphosis angles (r=-0.33, p=0.00), although there was no statistically correlation between trunk muscle ratio, lumbar and thoracic curvatures (p>0.05). The study demonstrated that an increase of fat ratio and decrease of muscle ratio in abdominal region or whole body shifts the spinal alignment which may adversely affect the spinal loading. Therefore, whole body composition should be taken into account in spine rehabilitation.

Keywords: body composition, lumbar lordosis, spinal alignment, thoracic kyphosis

Procedia PDF Downloads 365

Authors: Zineb Kassab, Nassima El Miri, A. Aboulkas, Abdellatif Barakat, Mounir El Achaby

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Recently, more attention has been given to biopolymers with a focus on sustainable development and environmental preservation. Following this tendency, the attempt has been made to replace polymers derived from petroleum with superior biodegradable polymers (biopolymers). In this context, biopolymers are considered potential replacements for conventional plastic materials. However, some of their properties must be improved for better competitiveness, especially regarding their mechanical, thermal and barrier properties. Bio-nanocomposite technology using nanofillers has already been proven as an effective way to produce new materials with specific properties and high performances. With the emergence of nanostructured bio-composite materials, incorporating elongated rod-like cellulose nanocrystals (CNC) has attracted more and more attention in the field of nanotechnology. This study is aimed to develop bio-composite films of biopolymer matrices [Carboxymethyle cellulose (CMC), Starch (ST), Chitosan (CS) and Polyvinyl alcohol (PVA)] reinforced with cellulose nanocrystals (CNC) using the solution casting method. The CNC were extracted at a nanometric scale from lignocellulosic fibers via sulfuric acid hydrolysis and then characterized using X-ray diffraction (XRD), thermogravimetric analysis (TGA), confocal microscopy, infrared spectroscopy (IR), atomic force and transmission electron microscopies (AFM and TEM) techniques. The as extracted CNC were used as a reinforcing phase to produce a variety of bio-composite films at different CNC loading (0.5-10 wt %) with specific properties. The rheological properties of film-forming solutions (FFS) of bio-composites were studied, and their relation to the casting process was evaluated. Then, the structural, optical transparency, water vapor permeability, thermal stability and mechanical properties of all prepared bio-composite films were evaluated and studied in this report. The high performances of these bio-composite films are expected to have potential in biomaterials or packaging applications.

Keywords: biopolymer composites, cellulose nanocrystals, food packaging, lignocellulosic fibers

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Authors: Adeiza Matthew, Oluwadamilola Abubakar

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Wood energy, also known as wood fuel, is a renewable energy source that is derived from woody biomass, which is organic matter that is harvested from forests, woodlands, and other lands. Woody biomass includes trees, branches, twigs, and other woody debris that can be used as fuel. Wood energy can be classified based on its sources, such as trees outside forests, residues from wood harvesting and conversion, and energy plantations. There are several policy frameworks that support the use of wood energy, including participatory forest management and agroforestry. These policies aim to promote the sustainable use of woody biomass as a source of energy while also protecting forests and wildlife habitats. There are several options for using wood as a fuel, including central heating systems, pellet-based systems, wood chip-based systems, log boilers, fireplaces, and stoves. Each of these options has its own benefits and drawbacks, and the most appropriate option will depend on factors such as the availability of woody biomass, the heating needs of the household or facility, and the local climate. In order to use wood as a fuel, it must be harvested and stored properly. Hardwood or softwood can be used as fuel, and the heating value of firewood depends on the species of tree and the degree of moisture content. Proper harvesting and storage of wood can help to minimize environmental impacts and improve wildlife habitats. The use of wood energy has several environmental impacts, including the release of greenhouse gases during combustion and the potential for air pollution from combustion by-products. However, wood energy can also have positive environmental impacts, such as the sequestration of carbon in trees and the reduction of reliance on fossil fuels. The regulation and legislation of wood energy vary by country and region, and there is an ongoing debate about the potential use of wood energy in renewable energy technologies. Wood energy is a renewable energy source that can be used to generate electricity, heat, and transportation fuels. Woody biomass is abundant and widely available, making it a potentially significant source of energy for many countries. The use of wood energy can create local economic and employment opportunities, particularly in rural areas. Wood energy can be used to reduce reliance on fossil fuels and reduce greenhouse gas emissions. Properly managed forests can provide a sustained supply of woody biomass for energy, helping to reduce the risk of deforestation and habitat loss. Wood energy can be produced using a variety of technologies, including direct combustion, co-firing with fossil fuels, and the production of biofuels. The environmental impacts of wood energy can be minimized through the use of best practices in harvesting, transportation, and processing. Wood energy is regulated and legislated at the national and international levels, and there are various standards and certification systems in place to promote sustainable practices. Wood energy has the potential to play a significant role in the transition to a low-carbon economy and the achievement of climate change mitigation goals.

Keywords: biomass, timber, charcoal, firewood

Procedia PDF Downloads 78

Authors: Arwin Malabanan, Carl Chester Ragudo, Jerome Tadiosa, John Dee Mangoba, Eric Augustus Tingatinga, Romeo Eliezer Longalong

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Concrete hollow blocks (CHB) are the most commonly used masonry block for walls in residential houses, school buildings and public buildings in the Philippines. During the recent 2013 Bohol earthquake (Mw 7.2), it has been proven that CHB walls are very vulnerable to severe external action like strong ground motion. In this paper, a numerical model of CHB structures is proposed, and seismic behavior of CHB houses is presented. In modeling, the Rigid Body Spring-Discrete Element method (RBS-DEM)) is used wherein masonry blocks are discretized into rigid elements and connected by nonlinear springs at preselected contact points. The shear and normal stiffness of springs are derived from the material properties of CHB unit incorporating the grout and mortar fillings through the volumetric transformation of the dimension using material ratio. Numerical models of reinforced and unreinforced walls are first subjected to linearly-increasing in plane loading to observe the different failure mechanisms. These wall models are then assembled to form typical model masonry houses and then subjected to the El Centro and Pacoima earthquake records. Numerical simulations show that the elastic, failure and collapse behavior of the model houses agree well with shaking table tests results. The effectiveness of the method in replicating failure patterns will serve as a basis for the improvement of the design and provides a good basis of strengthening the structure.

Keywords: concrete hollow blocks, discrete element method, earthquake, rigid body spring model

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Authors: Eun-Seop Kim, Eun-Ha Jang, Rana R. Kim, Sae-Byul Jang

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Objective: Preterm labor is the most common antecedent of preterm birth(PTB), which is characterized by regular uterine contraction before 37 weeks of pregnancy and cervical change. In acute preterm labor, tocolytics are administered as the first-line medication to suppress uterine contractions but rarely delay pregnancy to 37 weeks of gestation. On the other hand, according to the Korean Traditional Medicine, PTB is caused by the deficiency of Qi and unnecessary energy in the body of the mother. The aim of this study was to demonstrate the benefit of Traditional Korean Medicine as an adjuvant therapy in management of early uterine contractions and the prevention of PTB. Methods: It is a case report of a 38-year-old woman (0-0-6-0) hospitalized for irregular uterine contractions and cervical change at 33+3/7 weeks of gestation. Past history includes chemical pregnancies achieved by Artificial Rroductive Technology(ART), one stillbirth (at 7 weeks) and a laparoscopic surgery for endometriosis. After seven trials of IVF and articificial insemination, she had succeeded in conception via in-vitro fertilization (IVF) with help of Traditional Korean Medicine (TKM) treatments. Due to irregular uterine contractions and cervical changes, 2 TKM were prescribed: Gami-Dangguisan, and Antae-eum, known to nourish blood and clear away heat. 120ml of Gami-Dangguisan was given twice a day monring and evening along with same amount of Antae-eum once a day from 31 August 2013 to 28 November 2013. Tocolytics (Ritodrine) was administered as a first aid for maintenance of pregnancy. Information regarding progress until the delivery was collected during the patient’s visit. Results: On admission, the cervix of 15mm in length and cervical os with 0.5cm-dilated were observed via ultrasonography. 50% cervical effacement was also detected in physical examination. Tocolysis had been temporarily maintained. As a supportive therapy, TKM herbal preparations(gami-dangguisan and Antae-eum) were concomitantly given. As of 34+2/7 weeks of gestation, however intermittent uterine contractions appeared (5-12min) on cardiotocography and vaginal bleeding was also smeared at 34+3/7 weeks. However, enhanced tocolytics and continuous administration of herbal medicine sustained the pregnancy to term. At 37+2/7 weeks, no sign of labor with restored cervical length was confirmed. The woman gave a term birth to a healthy infant via vaginal delivery at 39+3/7 gestational weeks. Conclusions: This is the first successful case report about a preter labor patient administered with conventional tocolytic agents as well as TKM herbal decoctions, delaying delivery to term. This case deserves attention considering it is rare to maintain gestation to term only with tocolytic intervention. Our report implies the potential of herbal medicine as an adjuvant therapy for preterm labor treatment. Further studies are needed to assess the safety and efficacy of TKM herbal medicine as a therapeutic alternative for curing preterm birth.

Keywords: preterm labor, traditional Korean medicine, herbal medicine, integrative treatment, complementary and alternative medicine

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Authors: Sudhir Kumar Tewatia, Kanishck Tewatia, Anttriksh Tewatia

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Advancements in soil consolidation are discussed, and further improvements are proposed with particular reference to Tewatia’s Y-Y’ Approach, which is called the Settlement versus Rate of Settlement Approach in consolidation. A branch of calculus named Y-Y' (or y versus dy/dx) is suggested (as compared to the common X-Y', x versus dy/dx, dy/dx versus x or Newton-Leibniz branch) that solves some complicated/unsolved theoretical and practical problems in physical sciences (Physics, Chemistry, Mathematics, Biology, and allied sciences) and engineering in an amazingly simple and short manner, particularly when independent variable X is unknown and X-Y' Approach can’t be used. Complicated theoretical and practical problems in 1D, 2D, 3D Primary and Secondary consolidations with non-uniform gradual loading and irregularly shaped clays are solved with elementary school level Y-Y' Approach, and it is interesting to note that in X-Y' Approach, equations become more difficult while we move from one to three dimensions, but in Y-Y' Approach even 2D/3D equations are very simple to derive, solve, and use; rather easier sometimes. This branch of calculus will have a far-reaching impact on understanding and solving the problems in different fields of physical sciences and engineering that were hitherto unsolved or difficult to be solved by normal calculus/numerical/computer methods. Some particular cases from soil consolidation that basically creeps and diffusion equations in isolation and in combination with each other are taken for comparison with heat transfer. The Y-Y’ Approach can similarly be applied in wave equations and other fields wherever normal calculus works or fails. Soil mechanics uses mathematical analogies from other fields of physical sciences and engineering to solve theoretical and practical problems; for example, consolidation theory is a replica of the heat equation from thermodynamics with the addition of the effective stress principle. An attempt is made to give them mathematical analogies.

Keywords: calculus, clay, consolidation, creep, diffusion, heat, settlement

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Authors: Marta Kozuń, Krystian Toczewski, Sylwester Gerus, Justyna Wolicka, Kamila Boberek, Jarosław Filipiak, Dariusz Patkowski

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Long gap esophageal atresia is a congenital defect and is a challenge for pediatric surgeons all over the world. There are different surgical techniques in use to treat atresia. One of them is esophageal elongation but the optimal suture placement technique to achieve maximum elongation with low-risk complications is still unknown. The aim of the study was to characterize the process of esophageal elongation from the biomechanical point of view. Esophagi of white Pekin Duck was used as a model based on the size of this animal which is similar to a newborn (2.5-4kg). The specimens were divided into two groups: the control group (CG) and the group with sutures (SG). The esophagi of the control group were mounted in the grips of the MTS Tytron 250 testing machine and tensile test until rupture was performed. The loading speed during the test was 10mm/min. Then the SG group was tested. Each esophagus was cut into two equal parts and that were fused together using surgical sutures. The distance between both esophagus parts was 20mm. Ten both ends were mounted on the same testing machine and the tensile test with the same parameters was conducted. For all specimens, force and elongation were recorded. The biomechanical properties, i.e., the maximal force and maximal elongation, were determined on the basis of force-elongation curves. The maximal elongation was determined at the point of maximal force. The force achieved with the suture group was 10.1N±1.9N and 50.3N±11.6N for the control group. The highest elongation was also obtained for the control group: 18mm±3mm vs. 13.5mm ±2.4mm for the suture group. The presented study expands the knowledge of elongation of esophagi. It is worth emphasizing that the duck esophagus differs from the esophagus of a newborn, i.e., its wall lacks striated muscle cells. This is why the parts of animal esophagi used in the research are may characterized by different biomechanical properties in comparison with newborn tissue.

Keywords: long gap atresia treatment, esophageal elongation, biomechanical properties, soft tissue

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Authors: Ali Akbar, Seungho Shin, Sukkee Um

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The composition of catalyst layers (CLs) plays an important role in the overall performance and cost of the proton exchange membrane fuel cells (PEMFCs). Low platinum loading, high utilization, and more durable catalyst still remain as critical challenges for PEMFCs. In this study, a three-dimensional material network model is developed to visualize the nanostructure of carbon supported platinum Pt/C and Pt/VACNT catalysts in pursuance of maximizing the catalyst utilization. The quadruple-phase randomly generated CLs domain is formulated using quasi-random stochastic Monte Carlo-based method. This unique statistical approach of four-phase (i.e., pore, ionomer, carbon, and platinum) model is closely mimic of manufacturing process of CLs. Various CLs compositions are simulated to elucidate the effect of electrons, ions, and mass transport paths on the catalyst utilization factor. Based on simulation results, the effect of key factors such as porosity, ionomer contents and Pt weight percentage in Pt/C catalyst have been investigated at the represented elementary volume (REV) scale. The results show that the relationship between ionomer content and Pt utilization is in good agreement with existing experimental calculations. Furthermore, this model is implemented on the state-of-the-art Pt/VACNT CLs. The simulation results on Pt/VACNT based CLs show exceptionally high catalyst utilization as compared to Pt/C with different composition ratios. More importantly, this study reveals that the maximum catalyst utilization depends on the distance spacing between the carbon nanotubes for Pt/VACNT. The current simulation results are expected to be utilized in the optimization of nano-structural construction and composition of Pt/C and Pt/VACNT CLs.

Keywords: catalyst layer, platinum utilization, proton exchange membrane fuel cell, stochastic modeling

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Authors: Sharif Abdelghany

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Polymeric nanoparticles have been widely investigated as a controlled release drug delivery platform for the treatment of tuberculosis (TB). These nanoparticles were also readily internalised into macrophages, leading to high intracellular drug concentration. In this study two anti-TB drugs, amikacin and moxifloxacin were encapsulated into PLGA nanoparticles. The novelty of this work appears in: (1) the efficient encapsulation of two hydrophilic second-line anti-TB drugs, and (2) intramacrophage delivery of this synergistic combination potentially for rapid treatment of multi-drug resistant TB (MDR-TB). Two water-oil-water (w/o/w) emulsion strategies were employed in this study: (1) alginate coated PLGA nanoparticles, and (2) alginate entrapped PLGA nanoparticles. The average particle size and polydispersity index (PDI) of the alginate coated PLGA nanoparticles were found to be unfavourably high with values of 640 ± 32 nm and 0.63 ± 0.09, respectively. In contrast, the alginate entrapped PLGA nanoparticles were within the desirable particle size range of 282 - 315 nm and the PDI was 0.08 - 0.16, and therefore were chosen for subsequent studies. Alginate entrapped PLGA nanoparticles yielded a drug loading of over 10 µg/mg powder for amikacin, and more than 5 µg/mg for moxifloxacin and entrapment efficiencies range of approximately 25-31% for moxifloxacin and 51-59% for amikacin. To study macrophage uptake efficiency, the nanoparticles of alginate entrapped nanoparticle formulation were loaded with acridine orange as a marker, seeded to THP-1 derived macrophages and viewed under confocal microscopy. The particles were readily internalised into the macrophages and highly concentrated in the nucleus region. Furthermore, the anti-mycobacterial activity of the drug-loaded particles was evaluated using M. tuberculosis-infected macrophages, which revealed a significant reduction (4 log reduction) of viable bacterial count compared to the untreated group. In conclusion, the amikacin-moxifloxacin alginate entrapped PLGA nanoparticles are promising for further in vivo studies.

Keywords: moxifloxacin and amikacin, nanoparticles, multidrug resistant TB, PLGA

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Authors: Aniruddha Mitra, Abbas Rashidi, Shane Lewis, Jefferson Doehling, Alexis Pawlak, Jacob Schwartz, Imaobong Ekpo, Atin Adhikari

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Working or living close to demolition sites can increase risks of dust-related health problems. Demolition of concrete buildings may produce crystalline silica dust, which can be associated with a broad range of respiratory diseases including silicosis and lung cancers. Previous studies demonstrated significant associations between demolition dust exposure and increase in the incidence of mesothelioma or asbestos cancer. Dust is a generic term used for minute solid particles of typically <500 µm in diameter. Dust particles in demolition sites vary in a wide range of sizes. Larger particles tend to settle down from the air. On the other hand, the smaller and lighter solid particles remain dispersed in the air for a long period and pose sustained exposure risks. Submicron ultrafine particles and nanoparticles are respirable deeper into our alveoli beyond our body’s natural respiratory cleaning mechanisms such as cilia and mucous membranes and are likely to be retained in the lower airways. To our knowledge, how various demolition tasks release nanoparticles are largely unknown and previous studies mostly focused on course dust, PM2.5, and PM10. General belief is that the dust generated during demolition tasks are mostly large particles formed through crushing, grinding, or sawing of various concrete and wooden structures. Therefore, little consideration has been given to the generated submicron ultrafine and nanoparticles and their exposure levels. These data are, however, critically important because recent laboratory studies have demonstrated cytotoxicity of nanoparticles on lung epithelial cells. The above-described knowledge gaps were addressed in this study by a novel newly developed nanoparticle monitor, which was used for nanoparticle monitoring at two adjacent indoor and outdoor building demolition sites in southern Georgia. Nanoparticle levels were measured (n = 10) by TSI NanoScan SMPS Model 3910 at four different distances (5, 10, 15, and 30 m) from the work location as well as in control sites. Temperature and relative humidity levels were recorded. Indoor demolition works included acetylene torch, masonry drilling, ceiling panel removal, and other miscellaneous tasks. Whereas, outdoor demolition works included acetylene torch and skid-steer loader use to remove a HVAC system. Concentration ranges of nanoparticles of 13 particle sizes at the indoor demolition site were: 11.5 nm: 63 – 1054/cm³; 15.4 nm: 170 – 1690/cm³; 20.5 nm: 321 – 730/cm³; 27.4 nm: 740 – 3255/cm³; 36.5 nm: 1,220 – 17,828/cm³; 48.7 nm: 1,993 – 40,465/cm³; 64.9 nm: 2,848 – 58,910/cm³; 86.6 nm: 3,722 – 62,040/cm³; 115.5 nm: 3,732 – 46,786/cm³; 154 nm: 3,022 – 21,506/cm³; 205.4 nm: 12 – 15,482/cm³; 273.8 nm: Keywords: demolition dust, industrial hygiene, aerosol, occupational exposure

Procedia PDF Downloads 405

Authors: Edwin Lerch, Dirk Audring, Cuong Nguyen Mau, Duc Ninh Nguyen, The Cuong Nguyen, The Van Nguyen

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The National Load Dispatch Centre of Electricity Vietnam (EVNNLDC) and Siemens PTI investigated the stability of the electrical 500/220 kV transportation system of Vietnam. The general scope of the investigations is improving the stability of the Vietnam power system and giving the EVNNLDC staff the capability to decide how to deal with expected stability challenges in the future, which are related to the very fast growth of the system. Rapid system growth leads to a very high demand of power transmission from North to South. This was investigated by stability studies of interconnected power system with neighboring countries. These investigations are performed in close cooperation and coordination with the EVNNLDC project team. This important project includes data collection, measurement, model validation and investigation of relevant stability phenomena as well as training of the EVNNLDC staff. Generally, the power system of Vietnam has good voltage and dynamic stability. The main problems are related to the longitudinal system with more power generation in the North and Center, especially hydro power, and load centers in the South of Vietnam. Faults on the power transmission system from North to South risks the stability of the entire system due to a high power transfer from North to South and high loading of the 500 kV backbone. An additional problem is the weak connection to Cambodia power system which leads to interarea oscillations mode. Therefore, strengthening the power transfer capability by new 500kV lines or HVDC connection and balancing the power generation across the country will solve many challenges. Other countermeasures, such as wide area load shedding, PSS tuning and correct SVC placement will improve and stabilize the power system as well. Primary frequency reserve should be increased.

Keywords: dynamic power transmission system studies, blackout prevention, power system interconnection, stability

Procedia PDF Downloads 332

Authors: Sirajo Abubakar, Ismail Ahmad Abir, Muhammad Sabiu Bala, Muhammad Mustapha Adejo, Aravind Shanmugaveloo

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Over the years, land subsidence has been a serious threat mostly to urban areas. Land subsidence is the sudden sinking or gradual downward settling of the ground’s surface with little or no horizontal motion. In most areas, land subsidence is a slow process that covers a large area; therefore, it is sometimes left unnoticed. South of Johor is the area of interest for this project because it is going through rapid urbanization. The objective of this research is to evaluate and identify potential deformations in the south of Johor using integrated remote sensing and 2D resistivity methods. Synthetic aperture radar interferometry (InSAR) which is a remote sensing technique has the potential to map coherent displacements at centimeter to millimeter resolutions. Persistent scatterer interferometry (PSI) stacking technique was applied to Sentinel-1 data to detect the earth deformation in the study area. A dipole-dipole configuration resistivity profiling was conducted in three areas to determine the subsurface features in that area. This subsurface features interpreted were then correlated with the remote sensing technique to predict the possible causes of subsidence and uplifts in the south of Johor. Based on the results obtained, West Johor Bahru (0.63mm/year) and Ulu Tiram (1.61mm/year) are going through uplift due to possible geological uplift. On the other end, East Johor Bahru (-0.26mm/year) and Senai (-1.16mm/year) undergo subsidence due to possible fracture and granitic boulders loading. Land subsidence must be taken seriously as it can cause serious damages to infrastructures and human life. Monitoring land subsidence and taking preventive actions must be done to prevent any disasters.

Keywords: interferometric synthetic aperture radar, persistent scatter, minimum spanning tree, resistivity, subsidence

Procedia PDF Downloads 126

Authors: Afnan Ahmad, Shahid Ali, Mujahid Khan

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This research presents the parametric study of an existing earth fill dam located at Latamber, Karak city, Pakistan. The study consists of carrying out seepage analysis, slope stability analysis, and Earthquake analysis of the dam for the existing dam geometry and do the same for modified geometry. Dams are massive as well as expensive hydraulic structure, therefore it needs proper attention. Additionally, this dam falls under zone 2B region of Pakistan, which is an earthquake-prone area and where ground accelerations range from 0.16g to 0.24g peak. So it should be deal with great care, as the failure of any dam can cause irreparable losses. Similarly, seepage as well as slope failure can also cause damages which can lead to failure of the dam. Therefore, keeping in view of the importance of dam construction and associated costs, our main focus is to carry out parametric study of newly constructed dam. GeoStudio software is used for this analysis in the study in which Seep/W is used for seepage analysis, Slope/w is used for Slope stability analysis and Quake/w is used for earthquake analysis. Based on the geometrical, hydrological and geotechnical data, Seepage and slope stability analysis of different proposed geometries of the dam are carried out along with the Seismic analysis. A rigorous analysis was carried out in 2-D limit equilibrium using finite element analysis. The seismic study began with the static analysis, continuing by the dynamic response analysis. The seismic analyses permitted evaluation of the overall patterns of the Latamber dam behavior in terms of displacements, stress, strain, and acceleration fields. Similarly, the seepage analysis allows evaluation of seepage through the foundation and embankment of the dam, while slope stability analysis estimates the factor of safety of the upstream and downstream of the dam. The results of the analysis demonstrate that among multiple geometries, Latamber dam is secure against seepage piping failure and slope stability (upstream and downstream) failure. Moreover, the dam is safe against any dynamic loading and no liquefaction has been observed while changing its geometry in permissible limits.

Keywords: earth-fill dam, finite element, liquefaction, seepage analysis

Procedia PDF Downloads 148

Authors: Mariem Meddeb Sidhom, Souhayel Hedfi, Rjaibia Houda, Mehdi Dridi, Mohamed Ali Yousfi, Sâadia Gargouri

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Considering the important increase in costs of caspofungin treatments and ahead the evolution of its indication, pharmacy department was prompted to realize a review of the adequacy of prescriptions in the medical intensive care units (ICU). A retrospective observational study was conducted in Tunis military hospital concerning ICU prescriptions of caspofungin from 2008 until 2013. A pharmacist had returned to the patient’s medical records to collect data and to the microbiology department for parasitological results. The adequacy of prescriptions was evaluated by a pharmacist and an infectiologist parasitologist, referring to predefined scale of criteria resuming the indications of the marketing authorization (MA) and grade AI-AII of the guidelines of the Infectious Diseases Society of America (IDSA). Sixty two ICU patients have been treated with caspofungin during the period of study; however, 8 files were lost. Thus, 54 patients were included in the study having received 55 prescriptions of caspofungin. Males were a majority with 64.8% of the population. Mean age was 51 years. Caspofungin was indicated in accordance with the IDSA recommendations in 43.6% of the cases. The most case of non respect to the guidelines was the indication of caspofungin as empirical treatment in non neutropenic patients. Caspofungin was utilized as a first line treatment in 9 cases where it was possible to give fluconazole first, as germs were fluconazole- sensitive. Caspofungin was indicated in 2 patients with good renal function and in which nor amphotericin B, liposomal ampho B neither itraconazole had been previously used, as indicates the MA. The posology of caspofungin was respected in all prescriptions with a loading dose of 70 mg in the first day and a maintenance dose of 50 mg daily. Seven patients had received a daily dose of 70 mg, the recommended dose for people weighing more than 80 Kg. Caspofungin prescriptions are far to be adequately done. There is a clear need of optimization in indicating this molecule and that must be done in collaboration between the pharmacy department, the ICUs and parasitology department.

Keywords: caspofungin, prescription, intensive care units, marketing authorization, Tunisian hospital cohort

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Authors: Adu-Ampomah Yaw Junior

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Local procurement has become one of the latest trends in the discourse of sustainable tourism due to the economic benefits it generates for tourist destinations in developing countries. Local procurement helps in creating jobs which consequently helps in alleviating poverty. However, there have been limited studies on local procurement patterns in developing countries. Research on hotel procurement practices has mainly emphasized the challenges that hoteliers face when procuring locally, leaving questions regarding their motivations to engage in local procurement unanswered. The institutional theory provides a suitable framework to better understand these motivations as it underlines the importance of individual cognitive perceptions on issues in shaping organizational response strategies. More specifically, the extent to which an issue is perceived to belong to the organization’s responsibility. Also the organizational actors’ belief of losses or gains resultant from acting or not acting on an issue (degree of importance). Furthermore the organizational actors’ belief of the probability of resolving an issue (degree of feasibility). These factors influence how an organization will act on this issue. Hence, this paper adopts an institutional perspective to examine local procurement patterns of food by hoteliers in Ghana. Qualitative interviews with 20 procurement managers about their procurement practices and motivations, as well as interviews with different stakeholders for data triangulation purposes, indicated that most hotels sourced their food from middlemen who imported most of their products. However, direct importation was more prevalent foreign owned hotels as opposed to locally owned ones. Notwithstanding, the importation and the usage of foreign foods as opposed to local ones can be explained by the lack of pressure from NGOs and trade associations on hotels to act responsibly. Though guests’ menu preferences were perceived as important to hoteliers business operations, western tourists demand foreign food primarily with the foreign owned hotels make it less important to procure local produce. Lastly hoteliers, particularly those in foreign owned ones, perceive local procurement to be less feasible, raising concerns about quality and variety of local produce. The paper outlines strategies to improve the perception and degree of local Firstly, there is the need for stakeholder engagement in order to make hoteliers feel responsible for acting on the issue.Again it is crucial for Ghana government to promote and encourage hotels to buy local produce. Also, the government has to also make funds and storage facilities available for farmers to impact on the quality and quantity of local produce. Moreover, Sites need to be secured for farmers to engage in sustained farming.Furthermore, there is the need for collaborations between various stakeholders to organize training programs for farmers. Notwithstanding hotels need to market local produce to their guests. Finally, the Ghana hotels association has to encourage hotels to indulge in local procurement.

Keywords: sustainable tourism, feasible, important, local procurement

Procedia PDF Downloads 174

Authors: Wei Zhao, Yuxuan Yao, Hao Chen

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In order to find out the mechanical properties and failure behavior of lithium-ion batteries, drop hammer impact experiments and finite element simulations are carried out on batteries with different packed angles. Firstly, a drop hammer impact experiment system, which is based on the DHR-1808 drop hammer and oscilloscope, is established, and then a drop test of individual batteries and packed angles of 180 ° and 120 ° are carried out. The image of battery deformation, force-time curve and voltage-time curve are recorded. Secondly, finite element models of individual batteries and two packed angles are established, and the results of the test and simulation are compared. Finally, the mechanical characteristics and failure behavior of lithium-ion battery modules with the packed arrangement of 6 * 6 and packing angles of 180 °, 120 °, 90 ° and 60 ° are analyzed under the same velocity with different battery packing angles, and the same impact energy with different impact velocity and different packing angles. The result shows that the individual battery is destroyed completely in the drop hammer impact test with an initial impact velocity of 3m/s and drop height of 459mm, and the voltage drops to close to 0V when the test ends. The voltage drops to 12V when packed angle of 180°, and 3.6V when packed angle of 120°. It is found that the trend of the force-time curve between simulation and experiment is generally consistent. The difference in maximum peak value is 3.9kN for a packing angle of 180° and 1.3kN for a packing angle of 120°. Under the same impact velocity and impact energy, the strain rate of the battery module with a packing angle of 180° is the lowest, and the maximum stress can reach 26.7MPa with no battery short-circuited. The research under our experiment and simulation shows that the lithium-ion battery module with a packing angle of 180 ° is the least likely to be damaged, which can sustain the maximum stress under the same impact load.

Keywords: battery module, finite element simulation, power battery, packing angle

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Authors: Guillaume Mullier, Jean François Chatelain

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Carbon Fiber Reinforced Plastics (CFRPs) are widely used for advanced applications, in particular in aerospace, automotive and wind energy industries. Once cured to near net shape, CFRP parts need several finishing operations such as trimming, milling or drilling in order to accommodate fastening hardware and meeting the final dimensions. The present research aims to study the effect of the cutting temperature in trimming on the mechanical strength of high performance CFRP laminates used for aeronautics applications. The cutting temperature is of great importance when dealing with trimming of CFRP. Temperatures higher than the glass-transition temperature (Tg) of the resin matrix are highly undesirable: they cause degradation of the matrix in the trimmed edges area, which can severely affect the mechanical performance of the entire component. In this study, a 9.50 mm diameter CVD diamond coated carbide tool with six flutes was used to trim 24-plies CFRP laminates. A 300 m/min cutting speed and 1140 mm/min feed rate were used in the experiments. The tool was heated prior to trimming using a blowtorch, for temperatures ranging from 20°C to 300°C. The temperature at the cutting edge was measured using embedded K-Type thermocouples. Samples trimmed for different cutting temperatures, below and above Tg, were mechanically tested using three-points bending short-beam loading configurations. New cutting tools as well as worn cutting tools were utilized for the experiments. The experiments with the new tools could not prove any correlation between the length of cut, the cutting temperature and the mechanical performance. Thus mechanical strength was constant, regardless of the cutting temperature. However, for worn tools, producing a cutting temperature rising up to 450°C, thermal damage of the resin was observed. The mechanical tests showed a reduced mean resistance in short beam configuration, while the resistance in three point bending decreases with increase of the cutting temperature.

Keywords: composites, trimming, thermal damage, surface quality

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Authors: Titin Handayani, Adi Mulyanto, Fajar Eko Priyanto

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It is generally recognized, that algae could be an interesting option for reducing CO₂ emissions. Based on light and CO₂, algae can be used for the production various economically interesting products. Current algae cultivation techniques, however, still present a number of limitations. Efficient feeding of CO₂, especially on a large scale, is one of them. Current methods for CO₂ feeding to algae cultures rely on the sparging pure CO₂ or directly from flue gas. The limiting factor in this system is the solubility of CO₂ in water, which demands a considerable amount of energy for an effective gas to liquid transfer and leads to losses to the atmosphere. Due to the current ineffective methods for CO₂ introduction into algae ponds very large surface areas would be required for enough ponds to capture a considerable amount of the CO₂. The purpose of this study is to assess technology to capture carbon dioxide (CO₂) emissions generated by industry by utilizing of microalgae Chlorella sp. The microalgae were cultivated in a bioreactor culture pond raceway type. The result is expected to be useful in mitigating the effects of greenhouse gases in reducing the CO₂ emissions. The research activities include: (1) Characterization of boiler flue gas, (2) Operation of culture pond, (3) Sampling and sample analysis. The results of this study showed that the initial assessment absorption of the flue gas by microalgae using 1000 L raceway pond completed by heat exchanger were quite promising. The transfer of CO₂ into the pond culture system was run well. This identified from the success of cooling the boiler flue gas from the temperature of about 200 °C to below ambient temperature. Except for the temperature, the gas bubbles into the culture media were quite fine. Therefore, the contact between the gas and the media was well performed. The efficiency of CO₂ absorption by Chlorella sp reached 6.68 % with an average CO₂ loading of 0.29 g/L/day.

Keywords: Chlorella sp., CO2 emission, heat exchange, microalgae, milk industry, raceway pond

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Authors: Kennedy Zinn, Chris Anderson

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Chronic Covid syndrome (CCS) is a condition in which individuals who test positive for Covid-19 experience persistent symptoms after recovering from the virus. CCS affects every organ system, including the central nervous system. Neurological “long-haul” symptoms last from a few weeks to several months and include brain fog, chronic fatigue, dyspnea, mood dysregulation, and headaches. Data suggest that 10-30% of individuals testing positive for Covid-19 develop CCS. Current literature indicates a decreased quality of life in persistent symptoms. CCS is a pervasive and pernicious COVID-19 sequelae. More research is needed to understand risk factors, impact, and possible interventions. Research frequently cites cytokine storming as noteworthy etiology in CCS. Cytokine storming is a malfunctional immune response and facilitates multidimensional interconnected physiological responses. The most prominent responses include abnormal blood flow, hypoxia/hypoxemia, inflammation, and endothelial damage. Neurological impairments and pathogenesis in CCS parallel that of traumatic brain injury (TBI). Both exhibit impairments in memory, cognition, mood, sustained attention, and chronic fatigue. Evidence suggests abnormal blood flow, inflammation, and hypoxemia as shared causal factors. Cytokine storming is also typical in mTBI. The shared characteristics in symptoms and etiology suggest potential parallel routes of investigation that allow for better understanding of CCS. Research on the effect of altitude in mTBI varies. Literature finds decreased rates of concussions at higher altitudes. Other studies suggest that at a higher altitude, pre-existing mTBI symptoms are exacerbated. This may mean that in CCS, the geographical location where individuals live and the location where individuals experienced acute Covid-19 symptoms may influence the severity and risk of developing CCS. It also suggests that clinics which treat mTBI patients could also provide benefits for those with CCS. This study aims to examine the relationships between altitude and CCS as a risk factor and investigate the longevity and severity of symptoms in different altitudes. Existing patient data from a concussion clinic using fMRI scans and self-reported symptoms will be used for approximately 30 individuals with CCS symptoms. The association between acclimated altitude and CCS severity will be analyzed. Patients will be classified into low, medium, and high altitude groups and compared for differences on fMRI severity scores and self-reported measures. It is anticipated that individuals living in lower altitudes are at higher risk of developing more severe neuropsychological symptoms in CCS. It is also anticipated that a treatment approach for mTBI will also be beneficial to those with CCS.

Keywords: altitude, chronic covid syndrome, concussion, covid brain, EPIC treatment, fMRI, traumatic brain injury

Procedia PDF Downloads 114

Authors: Harsha Nagar, Vineet Aniya, Alka Kumari, Satyavathi B.

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In the present study, engineered bio-coal was produced from pressed seed cake, which otherwise is non-edible in origin. The production process involves a slow pyrolysis wherein, based on the optimization of process parameters; a substantial reduction in H/C and O/C of 77% was achieved with respect to the original ratio of 1.67 and 0.8, respectively. The bio-coal, so the product was found to have a higher heating value of 29899 kJ/kg with surface area 17 m²/g and pore volume of 0.002 cc/g. The functional characterization of bio-coal and its subsequent modification was carried out to enhance its active sites, which were further used as an adsorbent material for removal of 2,4,6-Trichlorophenol (2,4,6-TCP) herbicide from the aqueous stream. The point of zero charge for the bio-coal was found to be pH < 3 where its surface is positively charged and attracts anions resulting in the maximum 2, 4, 6-TCP adsorption at pH 2.0. The parametric optimization of the adsorption process was studied based on the Box-Behken design with the desirability approach. The results showed optimum values of adsorption efficiency of 74.04% and uptake capacity of 118.336 mg/g for an initial metal concentration of 250 mg/l and particle size of 0.12 mm at pH 2.0 and 1 g/L of bio-coal loading. Negative Gibbs free energy change values indicated the feasibility of 2,4,6-TCP adsorption on biochar. Decreasing the ΔG values with the rise in temperature indicated high favourability at low temperatures. The equilibrium modeling results showed that both isotherms (Langmuir and Freundlich) accurately predicted the equilibrium data, which may be attributed to the different affinity of the functional groups of bio-coal for 2,4,6-TCP removal. The possible mechanism for 2,4,6-TCP adsorption is found to be physisorption (pore diffusion, p*_p electron donor-acceptor interaction, H-bonding, and van der Waals dispersion forces) and chemisorption (phenolic and amine groups chemical bonding) based on the kinetics data modeling.

Keywords: engineered biocoal, 2, 4, 6-trichlorophenol, box behnken design, biosorption

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Authors: Esmeralda Hysenbelliu

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The aim of this paper is to present the QoE (Quality of Experience) IPTV SDN-based media streaming server enhanced architecture for configuring, controlling, management and provisioning the improved delivery of IPTV service application with low cost, low bandwidth, and high security. Furthermore, it is given a virtual QoE IPTV SDN-based topology to provide an improved IPTV service based on QoE Control and Management of multimedia services functionalities. Inside OpenFlow SDN Controller there are enabled in high flexibility and efficiency Service Load-Balancing Systems; based on the Loading-Balance module and based on GeoIP Service. This two Load-balancing system improve IPTV end-users Quality of Experience (QoE) with optimal management of resources greatly. Through the key functionalities of OpenFlow SDN controller, this approach produced several important features, opportunities for overcoming the critical QoE metrics for IPTV Service like achieving incredible Fast Zapping time (Channel Switching time) < 0.1 seconds. This approach enabled Easy and Powerful Transcoding system via FFMPEG encoder. It has the ability to customize streaming dimensions bitrates, latency management and maximum transfer rates ensuring delivering of IPTV streaming services (Audio and Video) in high flexibility, low bandwidth and required performance. This QoE IPTV SDN-based media streaming architecture unlike other architectures provides the possibility of Channel Exchanging between several IPTV service providers all over the word. This new functionality brings many benefits as increasing the number of TV channels received by end –users with low cost, decreasing stream failure time (Channel Failure time < 0.1 seconds) and improving the quality of streaming services.

Keywords: improved quality of experience (QoE), OpenFlow SDN controller, IPTV service application, softwarization

Procedia PDF Downloads 130

Authors: Fernanda Mary R. G. Da Silva, Adriana C. F. Mozzambani, Marcelo F. Mello

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Introduction: Sexual assault against children and adolescents is a public health problem with serious consequences on their quality of life, especially for those who develop post-traumatic stress disorder (PTSD). The broad literature in this research area points to greater losses in verbal learning, explicit memory, speed of information processing, attention and executive functioning in PTSD. Objective: To compare the neuropsychological functions of adolescents from 14 to 17 years of age, victims of sexual violence with PTSD with those of healthy controls. Methodology: Application of a neuropsychological battery composed of the following subtests: WASI vocabulary and matrix reasoning; Digit subtests (WISC-IV); verbal auditory learning test RAVLT; Spatial Span subtest of the WMS - III scale; abbreviated version of the Wisconsin test; concentrated attention test - D2; prospective memory subtest of the NEUPSILIN scale; five-digit test - FDT and the Stroop test (Trenerry version) in adolescents with a history of sexual violence in the previous six months, referred to the Prove (Violence Care and Research Program of the Federal University of São Paulo), for further treatment. Results: The results showed a deficit in the word coding process in the RAVLT test, with impairment in A3 (p = 0.004) and A4 (p = 0.016) measures, which compromises the verbal learning process (p = 0.010) and the verbal recognition memory (p = 0.012), seeming to present a worse performance in the acquisition of verbal information that depends on the support of the attentional system. A worse performance was found in list B (p = 0.047), a lower priming effect p = 0.026, that is, lower evocation index of the initial words presented and less perseveration (p = 0.002), repeated words. Therefore, there seems to be a failure in the creation of strategies that help the mnemonic process of retention of the verbal information necessary for learning. Sustained attention was found to be impaired, with greater loss of setting in the Wisconsin test (p = 0.023), a lower rate of correct responses in stage C of the Stroop test (p = 0.023) and, consequently, a higher index of erroneous responses in C of the Stroop test (p = 0.023), besides more type II errors in the D2 test (p = 0.008). A higher incidence of total errors was observed in the reading stage of the FDT test p = 0.002, which suggests fatigue in the execution of the task. Performance is compromised in executive functions in the cognitive flexibility ability, suggesting a higher index of total errors in the alternating step of the FDT test (p = 0.009), as well as a greater number of persevering errors in the Wisconsin test (p = 0.004). Conclusion: The data from this study suggest that sexual violence and PTSD cause significant impairment in the neuropsychological functions of adolescents, evidencing risk to quality of life in stages that are fundamental for the development of learning and cognition.

Keywords: adolescents, neuropsychological functions, PTSD, sexual violence

Procedia PDF Downloads 114

Authors: Panagiotis Lemonakis, Nikolaos Moisiadis, Andromachi Gkoutzini, George Kaliabetsos, Nikos Eliou

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The proper surface water drainage not only affects vehicle movement dynamics but also increases the likelihood of an accident due to the fact that inadequate drainage is associated with potential hydroplaning and splash and spray driving conditions. Nine solutions have been proposed to address hydroplaning in sections with inadequate drainage, e.g., augmented superelevation and longitudinal rates, reduction of runoff length, and skew superelevation. The latter has been extensively implemented in highways recently, enhancing the safety level in the applied road segments in regards to the effective drainage of the rainwater. However, the concept of the skew superelevation has raised concerns regarding the driver’s comfort when traveling over skew superelevation sections, particularly at high speeds. These concerns alleviated through the concept of the round-up skew superelevation, which reduces both the lateral and the vertical acceleration imposed to the drivers and hence, improves comfort and traffic safety. Various research studies aimed at investigating driving comfort by evaluating the lateral and vertical accelerations sustained by the road users and vehicles. These studies focused on the influence of the skew superelevation to passenger cars, buses and trucks, and the drivers themselves, traveling at a certain range of speeds either below or above the design speed. The outcome of these investigations which based on the use of simulations, revealed that the imposed accelerations did not exceed the statutory thresholds even when the travelling speed was significantly greater than the design speed. Nevertheless, the effect of the skew superelevation to other vehicle types for instance, motorcycles, has not been investigated so far. The present research study aims to bridge this gap by investigating the impact of skew superelevation on the motorcycle rider’s comfort. Power two-wheeler riders are susceptible to any changes on the pavement surface and therefore a comparison between the traditional superelevation practice and the skew superelevation concept is of paramount importance. The methodology based on the utilization of sophisticated software in order to design the model of the road for several values of the longitudinal slope. Based on the values of the slopes and the use of a mathematical equation, the accelerations imposed on the wheel of the motorcycle were calculated. Due to the fact that the final aim of the study is the influence of the skew superelevation to the rider, it was deemed necessary to convey the calculated accelerations from the wheel to the rider. That was accomplished by implementing the quarter car suspension model adjusted to the features of two-wheeler vehicles. Finally, the accelerations derived from this process evaluated according to specific thresholds originated from the International Organization for Standardization, which correspond to certain levels of comfort. The most important conclusion drawn is that the comfort of the riders is not dependent on the form of road gradient to a great extent due to the fact that the vertical acceleration imposed to the riders took similar values regardless of the value of the longitudinal slope.

Keywords: acceleration, comfort, motorcycle, safety, skew superelevation

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Authors: Wen-Chyan Tsai, Syed S. H. Rizvi

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Organic solvent residues are always associated with liposomes produced by the traditional techniques like the thin film hydration and reverse phase evaporation methods, which limit the applications of these vesicles in the pharmaceutical, food and cosmetic industries. Our objective was to develop a novel and benign process of liposomal microencapsulation by using supercritical carbon dioxide (SC-CO2) as the sole phospholipid-dissolving medium and a green substitute for organic solvents. This process consists of supercritical fluid extraction followed by rapid expansion via a nozzle and automatic cargo suction. Lecithin and cholesterol mixed in 10:1 mass ratio were dissolved in SC-CO2 at 20 ± 0.5 MPa and 60 oC. After at least two hours of equilibrium, the lecithin/cholesterol-laden SC-CO2 was passed through a 1000-micron nozzle and immediately mixed with the cargo solution to form liposomes. Liposomal micro-encapsulation was conducted at three pressures (8.27, 12.41, 16.55 MPa), three temperatures (75, 83 and 90 oC) and two flow rates (0.25 ml/sec and 0.5 ml/sec). Liposome size, zeta potential and encapsulation efficiency were characterized as functions of the operating parameters. The average liposomal size varied from 400-500 nm to 1000-1200 nm when the pressure was increased from 8.27 to 16.55 MPa. At 12.41 MPa, 90 oC and 0.25 ml per second of 0.2 M glucose cargo loading rate, the highest encapsulation efficiency of 31.65 % was achieved. Under a confocal laser scanning microscope, large unilamellar vesicles and multivesicular vesicles were observed to make up a majority of the liposomal emulsion. This new approach is a rapid and continuous process for bulk production of liposomes using a green solvent. Based on the results to date, it is feasible to apply this technique to encapsulate hydrophilic compounds inside the aqueous core as well as lipophilic compounds in the phospholipid bilayers of the liposomes for controlled release, solubility improvement and targeted therapy of bioactive compounds.

Keywords: liposome, micro encapsulation, supercritical carbon dioxide, non-toxic process

Procedia PDF Downloads 413