Search results for: oil droplet size

Authors: A. Y. Purnama, N. Yasufuku

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The bridge structure is a building that has to be maintained, especially for the elastomeric bearing. The girder of the bridge needs to be lifted upward to maintain this elastomeric bearing, that needs high cost. Nowadays, integral abutment bridges are becoming popular. The integral abutment bridge is less costly because the elastomeric bearings are eliminated, which reduces the construction cost and maintenance costs. However, when this elastomeric bearing removed, the girder movement due to environmental thermal forces directly support by pile foundation, and it needs to be considered in the design. In case of pile foundation in a stiff soil, in the top area of the pile cannot move freely due to the fixed condition by soil stiffness. Pre-bored pile system can be used to increase the flexibility of pile foundation using a pre-bored hole that filled with elastic materials, but the behavior of soil-pile interaction and soil response due to this system is still rarely explained. In this paper, an experimental study using small-scale laboratory model test conducted in a half size model. Single flexible pile model embedded in sandy soil with the pre-bored ring, which filled with the filler material. The testing box made from an acrylic glass panel as observation area of the pile shaft to monitor the displacement of the pile during the lateral loading. The failure behavior of the soil inside the pre-bored ring and around the pile shaft was investigated to determine the point of pile rotation and the movement of this point due to the pre-bored ring system along the pile shaft. Digital images were used to capture the deformations of the soil and pile foundation during the loading from the acrylic glass on the side of the testing box. The results were presented in the form of lateral load resistance charts against the pile shaft displacement. The failure pattern result also established due to the cyclic lateral loading. The movement of the rotational point was measured due to the pre-bored system filled with appropriate filler material. Based on the findings, design considerations for pre-bored pile system due to cyclic lateral loading can be introduced.

Keywords: failure behavior, pre-bored pile system, cyclic lateral loading, sandy soil

Procedia PDF Downloads 233

Authors: Lina Ismail Jassim, Robiah Yunus

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To successfully drill oil or gas well, two main characteristics of numerous other tasks of an efficient drilling fluid are required, which are suspended and carrying cuttings from the beneath wellbore to the surface and managed between pore (formation) and hydrostatic pressure (mud pressure). Several factors like mud composition and its rheology, wellbore design, drilled cuttings characteristics and drilling string rotation contribute to drill wellbore successfully. Simulation model can support an appropriate indication on the drilling fluid performance in the real field as Genting Timur field, located in Pahang in Malaysia on 4295 m depth, held the world record in Sempah Muda 1 (Vertical). A detailed 3 dimensional CFD analysis of vertical, concentric annular two phase flow was developed to study and asses Herschel Bulkley drilling fluid. The effect of Hematite, Barite and calcium carbonates types and size of cutting rock particles on such flow is analyzed. The vertical flows are also associated with a good amount of temperature variation along the depth. This causes a good amount of change in viscosity of the fluid, which is non-Newtonian in nature. Good understanding of the nature of such flows is imperative in developing and maintaining successful vertical well systems. A detailed analysis of flow characteristics due to the drill pipe rotation is done in this work. The inner cylinder of the annulus gets different rotational speed, depending upon the operating conditions. This speed induces a good swirl on the particles and primary fluids which interpret in Ester based drilling fluid cleaning well ability, which in turn determines energy loss along the pipe. Energy loss is assessed in this work in terms of wall shear stress and pressure drop along the pipe. The flow is under an adverse pressure gradient condition, which causes chance of reversed flow and transfers the rock cuttings to the surface.

Keywords: concentric annulus, non-Newtonian, two phase, Herschel Bulkley

Procedia PDF Downloads 308

Authors: Alireza Monzavi Chaleshtari, Maryam Aliakbari

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Objective: The aim of this study was to investigate the prediction of child attachment style based on a positive and safe combination parenting method mediated by maternal attachment styles in children with attention deficit hyperactivity disorder. Method: The design of the present study was descriptive of correlation and structural equations and applied in terms of purpose. The population of this study includes all children with attention deficit hyperactivity disorder living in Chaharmahal and Bakhtiari province and their mothers. The sample size of the above study includes 165children with attention deficit hyperactivity disorder in Chaharmahal and Bakhtiari province with their mothers, who were selected by purposive sampling method based on the inclusion criteria. The obtained data were analyzed in two sections of descriptive and inferential statistics. In the descriptive statistics section, statistical indices of mean, standard deviation, frequency distribution table and graph were used. In the inferential section, according to the nature of the hypotheses and objectives of the research, the data were analyzed using Pearson correlation coefficient tests, Bootstrap test and structural equation model. findings:The results of structural equation modeling showed that the research models fit and showed a positive and safe combination parenting style mediated by the mother attachment style has an indirect effect on the child attachment style. Also, a positive and safe combined parenting style has a direct relationship with child attachment style, and She has a mother attachment style. Conclusion:The results and findings of the present study show that there is a significant relationship between positive and safe combination parenting methods and attachment styles of children with attention deficit hyperactivity disorder with maternal attachment style mediation. Therefore, it can be expected that parents using a positive and safe combination232 parenting method can effectively lead to secure attachment in children with attention deficit hyperactivity disorder.

Keywords: child attachment style, positive and safe parenting, maternal attachment style, ADHD

Procedia PDF Downloads 66

Authors: P. Dhesi, R. Burns

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Background: The UK has one of the largest immigration detention estates in Europe and is under increasing scrutiny, particularly regarding the lack of transparency over the use of detention and the conditions. Therefore, this research seeks to explore the professional perceptions of the ability of immigration detention in the UK to promote health and dignity. Methods: A phenomenological approach to qualitative methods were used, with social constructivist theorisations of health and dignity. Seven semi-structured interviews were conducted using Microsoft Teams. Participants included a range of immigration detention stakeholders who have visited closed immigration detention centres in the UK in a professional capacity. Recorded interviews were transcribed verbatim, and analysis was data-driven through inductive reflexive thematic analysis of the entire data set to account for the small sample size. This study received ethical approval from University College London Research Ethics Committee. Results: Two global themes were created through analysis: apathetic place and hostile space. Apathetic place discusses the lack of concern for detainees' daily living and healthcare needs within immigration detention in the UK. This is explored through participants' perceptions of the lack of ability of monitoring and evaluation processes to ensure detainees are able to live with dignity and understand the unfulfilled duty of care that exists in detention. Hostile space discusses immigration detention in the UK as a wider system of hostility. This is explored through the disempowering impact on detainees, the perception of a failing system as a result of inadequate safeguarding procedures, and a belief that the intention of immigration detention is misaligned with its described purpose. Conclusion: This research explains why the current immigration detention system in the UK is unable to promote health and dignity, offering a social justice and action-orientated approach to research in this sphere. The findings strengthen the discourse against the use of detention as an immigration control tool in the UK. Implications for further research include a stronger emphasis on investigating alternatives to detention and culturally considerate opportunities for patient-centred healthcare.

Keywords: access to healthcare, dignity, health, immigration detention, migrant, refugee, UK

Procedia PDF Downloads 103

Authors: Anamika Sahu

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The Himalayas, like many mountainous regions, is susceptible to multiple hazards. In recent times, the frequency of such disasters is continuously increasing due to extreme weather phenomena. These natural hazards are responsible for irreparable human and economic loss. The Indian Himalayas has repeatedly been ruptured by great earthquakes in the past and has the potential for a future large seismic event as it falls under the seismic gap. Damages caused by earthquakes are different in different localities. It is well known that, during earthquakes, damage to the structure is associated with the subsurface conditions and the quality of construction materials. So, for sustainable mountain development, prior estimation of site characterization will be valuable for designing and constructing the space area and for efficient mitigation of the seismic risk. Both geotechnical and geophysical investigation of the subsurface is required to describe the subsurface complexity. In mountainous regions, geophysical methods are gaining popularity as areas can be studied without disturbing the ground surface, and also these methods are time and cost-effective. The MASW method is used to calculate the Vs30. Vs30 is the average shear wave velocity for the top 30m of soil. Shear wave velocity is considered the best stiffness indicator, and the average of shear wave velocity up to 30 m is used in National Earthquake Hazards Reduction Program (NEHRP) provisions (BSSC,1994) and Uniform Building Code (UBC), 1997 classification. Parameters obtained through geotechnical investigation have been integrated with findings obtained through the subsurface geophysical survey. Joint interpretation has been used to establish inter-relationships among mineral constituents, various textural parameters, and unconfined compressive strength (UCS) with shear wave velocity. It is found that results obtained through the MASW method fitted well with the laboratory test. In both conditions, mineral constituents and textural parameters (grain size, grain shape, grain orientation, and degree of interlocking) control the petrophysical and mechanical properties of rocks and the behavior of shear wave velocity.

Keywords: MASW, mechanical, petrophysical, site characterization

Procedia PDF Downloads 86

Authors: Mohamed Dhouibi, Bogdan Stirbu, Chabotier André, Marc Pirlot

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Internal barrel wear is a major factor affecting the performance of small caliber guns in their different life phases. Wear analysis is, therefore, a very important process for understanding how wear occurs, where it takes place, and how it spreads with the aim on improving the accuracy and effectiveness of small caliber weapons. This paper discusses the measurement and analysis of combustion chamber wear for a small-caliber gun using a Coordinate Measuring Machine (CMM). Initially, two different NATO small caliber guns: 5.56x45mm and 7.62x51mm, are considered. A Micura Zeiss Coordinate Measuring Machine (CMM) equipped with the VAST XTR gold high-end sensor is used to measure the inner profile of the two guns every 300-shot cycle. The CMM parameters, such us (i) the measuring force, (ii) the measured points, (iii) the time of masking, and (iv) the scanning velocity, are investigated. In order to ensure minimum measurement error, a statistical analysis is adopted to select the reliable CMM parameters combination. Next, two measurement strategies are developed to capture the shape and the volume of each gun chamber. Thus, a task-specific measurement uncertainty (TSMU) analysis is carried out for each measurement plan. Different approaches of TSMU evaluation have been proposed in the literature. This paper discusses two different techniques. The first is the substitution method described in ISO 15530 part 3. This approach is based on the use of calibrated workpieces with similar shape and size as the measured part. The second is the Monte Carlo simulation method presented in ISO 15530 part 4. Uncertainty evaluation software (UES), also known as the Virtual Coordinate Measuring Machine (VCMM), is utilized in this technique to perform a point-by-point simulation of the measurements. To conclude, a comparison between both approaches is performed. Finally, the results of the measurements are verified through calibrated gauges of several dimensions specially designed for the two barrels. On this basis, an experimental database is developed for further analysis aiming to quantify the relationship between the volume of wear and the muzzle velocity of small caliber guns.

Keywords: coordinate measuring machine, measurement uncertainty, erosion and wear volume, small caliber guns

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Authors: Nuri Balta, Ali Eryilmaz

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High-quality teachers are the key to improve student learning. Without a professional development of the teachers, the improvement of student success is difficult and incomplete. This study offers an in-service training course model for professional development of teachers (PD) entitled "teachers teaching teachers" (TTT). The basic premise of the PD program, designed for this study, was primarily aimed to increase the subject matter knowledge of high school physics teachers. The TTT course (the three hour long workshops), organized for this study, lasted for seven weeks with seventeen teachers took part in the TTT program at different amounts. In this study, the effect of the TTT program on teachers’ knowledge improvement was searched through the modern physics unit (MPU). The participating teachers taught the unit to one of their grade ten classes earlier, and they taught another equivalent class two months later. They were observed in their classes both before and after TTT program. The teachers were divided into placebo and the treatment groups. The aim of Solomon four-group design is an attempt to eliminate the possible effect of pre-test. However, in this study the similar design was used to eliminate the effect of pre teaching. The placebo group teachers taught their both classes as regular and the treatment group teachers had TTT program between the two teachings. The class observation results showed that the TTT program increased teachers’ knowledge and skills in teaching MPU. Further, participating in the TTT program caused teachers to teach the MPU in accordance with the requirements of the curriculum. In order to see any change in participating teachers’ success, an achievement test was applied to them. A large effect size (dCohen=.93) was calculated for the effect of TTT program on treatment group teachers’ achievement. The results suggest that staff developers should consider including topics, attractive to teachers, in-service training programs (a) to help teachers’ practice teaching the new topics (b) to increase the participation rate. During the conduction of the TTT courses, it was observed that teachers could not end some discussions and explain some concepts. It is now clear that teachers need support, especially when discussing counterintuitive concepts such as modern physics concepts. For this reason it is recommended that content focused PD programs be conducted at the helm of a scholarly coach.

Keywords: high school physics, in-service training course, modern physics unit, teacher professional development

Procedia PDF Downloads 197

Authors: L. Mentar, O. Baka, A. Azizi

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Zinc oxide as a wide band semiconductor materials, especially nanostructured materials, have potential applications in large-area such as electronics, sensors, photovoltaic cells, photonics, optical devices and optoelectronics due to their unique electrical and optical properties and surface properties. The feasibility of ZnO for these applications is due to the successful synthesis of diverse ZnO nanostructures, including nanorings, nanobows, nanohelixes, nanosprings, nanobelts, nanotubes, nanopropellers, nanodisks, and nanocombs, by different method. Among various synthesis methods, electrochemical deposition represents a simple and inexpensive solution based method for synthesis of semiconductor nanostructures. In this study, the electrodeposition method was used to produce zinc oxide (ZnO) nanostructures on fluorine-doped tin oxide (FTO)-coated conducting glass substrate as TCO from chloride bath. We present a systematic study on the effects of the concentration of chloride anion on the properties of ZnO. The influence of KCl concentrations on the electrodeposition process, morphological, structural and optical properties of ZnO nanostructures was examined. In this research electrochemical deposition of ZnO nanostructures is investigated using conventional electrochemical measurements (cyclic voltammetry and Mott-Schottky), scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. The potentials of electrodeposition of ZnO were determined using the cyclic voltammetry. From the Mott-Schottky measurements, the flat-band potential and the donor density for the ZnO nanostructure are determined. SEM images shows different size and morphology of the nanostructures and depends greatly on the KCl concentrations. The morphology of ZnO nanostructures is determined by the corporated action between [Zn(NO3)2] and [Cl-].Very netted hexagonal grains are observed for the nanostructures deposited at 0.1M of KCl. XRD studies revealed that the all deposited films were polycrystalline in nature with wurtzite phase. The electrodeposited thin films are found to have preferred oriented along (002) plane of the wurtzite structure of ZnO with c-axis normal to the substrate surface for sample at different concentrations of KCl. UV-Visible spectra showed a significant optical transmission (~80%), which decreased with low Cl-1 concentrations. The energy band gap values have been estimated to be between 3.52 and 3.80 eV.

Keywords: electrodeposition, ZnO, chloride ions, Mott-Schottky, SEM, XRD

Procedia PDF Downloads 290

Authors: O. Anwar Beg, Armghan Zubair, Sireetorn Kuharat, Meisam Babaie

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In this work, motivated by rocket channel cooling applications, we describe recent CFD simulations of turbulent convective heat transfer in mini-channels at different aspect ratios. ANSYS FLUENT software has been employed with a mean average error of 5.97% relative to Forrest’s MIT cooling channel study (2014) at a Reynolds number of 50,443 with a Prandtl number of 3.01. This suggests that the simulation model created for turbulent flow was suitable to set as a foundation for the study of different aspect ratios in the channel. Multiple aspect ratios were also considered to understand the influence of high aspect ratios to analyse the best performing cooling channel, which was determined to be the highest aspect ratio channels. Hence, the approximate 28:1 aspect ratio provided the best characteristics to ensure effective cooling. A mesh convergence study was performed to assess the optimum mesh density to collect accurate results. Hence, for this study an element size of 0.05mm was used to generate 579,120 for proper turbulent flow simulation. Deploying a greater bias factor would increase the mesh density to the furthest edges of the channel which would prove to be useful if the focus of the study was just on a single side of the wall. Since a bulk temperature is involved with the calculations, it is essential to ensure a suitable bias factor is used to ensure the reliability of the results. Hence, in this study we have opted to use a bias factor of 5 to allow greater mesh density at both edges of the channel. However, the limitations on mesh density and hardware have curtailed the sophistication achievable for the turbulence characteristics. Also only linear rectangular channels were considered, i.e. curvature was ignored. Furthermore, we only considered conventional water coolant. From this CFD study the variation of aspect ratio provided a deeper appreciation of the effect of small to high aspect ratios with regard to cooling channels. Hence, when considering an application for the channel, the geometry of the aspect ratio must play a crucial role in optimizing cooling performance.

Keywords: rocket channel cooling, ANSYS FLUENT CFD, turbulence, convection heat transfer

Procedia PDF Downloads 150

Authors: Dmitry Lukyanov, Sergey Shevchenko, Alexander Kukaev

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Modern MEMS gyroscopes have strengthened their position in motion control systems and have led to the creation of tactical grade sensors (better than 15 deg/h). This was achieved by virtue of the success in micro- and nanotechnology development, cooperation among international experts and the experience gained in the mass production of MEMS gyros. This production is knowledge-intensive, often unique and, therefore, difficult to develop, especially due to the use of 3D-technology. The latter is usually associated with manufacturing of inertial masses and their elastic suspension, which determines the vibration and shock resistance of gyros. Today, consumers developing highly dynamic objects or objects working under extreme conditions require the gyro shock resistance of up to 65 000 g and the measurement range of more than 10 000 deg/s. Such characteristics can be achieved by solid-state gyroscopes (SSG) without inertial masses or elastic suspensions, which, for example, can be constructed with molecular kinetics of bulk or surface acoustic waves (SAW). Excellent effectiveness of this sensors production and a high level of structural integration provides basis for increased accuracy, size reduction and significant drop in total production costs. Existing principles of SAW-based sensors are based on the theory of SAW propagation in rotating coordinate systems. A short introduction to the theory of a gyroscopic (Coriolis) effect in SAW is provided in the report. Nowadays more and more applications require passive and wireless sensors. SAW-based gyros provide an opportunity to create one. Several design concepts incorporating reflective delay lines were proposed in recent years, but faced some criticism. Still, the concept is promising and is being of interest in St. Petersburg Electrotechnical University. Several experimental models were developed and tested to find the minimal configuration of a passive and wireless SAW-based gyro. Structural schemes, potential characteristics and known limitations are stated in the report. Special attention is dedicated to a novel method of a FEM modeling with piezoelectric and gyroscopic effects simultaneously taken into account.

Keywords: FEM simulation, gyroscope, OOFELIE, surface acoustic wave, wireless sensing

Procedia PDF Downloads 365

Authors: Allan F. F. Alves, Fernando A. Bacchim Neto, Guilherme Giacomini, Marcela de Oliveira, Ana L. M. Pavan, Maria E. D. Rosa, Diana R. Pina

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Stroke is a worldwide concern, only in Brazil it accounts for 10% of all registered deaths. There are 2 stroke types, ischemic (87%) and hemorrhagic (13%). Early diagnosis is essential to avoid irreversible cerebral damage. Non-enhanced computed tomography (NECT) is one of the main diagnostic techniques used due to its wide availability and rapid diagnosis. Detection depends on the size and severity of lesions and the time spent between the first symptoms and examination. The Alberta Stroke Program Early CT Score (ASPECTS) is a subjective method that increases the detection rate. The aim of this work was to implement an image segmentation system to enhance ischemic stroke and to quantify the area of ischemic and hemorrhagic stroke lesions in CT scans. We evaluated 10 patients with NECT examinations diagnosed with ischemic stroke. Analyzes were performed in two axial slices, one at the level of the thalamus and basal ganglion and one adjacent to the top edge of the ganglionic structures with window width between 80 and 100 Hounsfield Units. We used different image processing techniques such as morphological filters, discrete wavelet transform and Fuzzy C-means clustering. Subjective analyzes were performed by a neuroradiologist according to the ASPECTS scale to quantify ischemic areas in the middle cerebral artery region. These subjective analysis results were compared with objective analyzes performed by the computational algorithm. Preliminary results indicate that the morphological filters actually improve the ischemic areas for subjective evaluations. The comparison in area of the ischemic region contoured by the neuroradiologist and the defined area by computational algorithm showed no deviations greater than 12% in any of the 10 examination tests. Although there is a tendency that the areas contoured by the neuroradiologist are smaller than those obtained by the algorithm. These results show the importance of a computer aided diagnosis software to assist neuroradiology decisions, especially in critical situations as the choice of treatment for ischemic stroke.

Keywords: ischemic stroke, image processing, CT scans, Fuzzy C-means

Procedia PDF Downloads 366

Authors: E. Kilicay, Z. Karahaliloglu, B. Hazer, E. B. Denkbas

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In this study, we have prepared concanavaline A (ConA) functionalized curcumin (CUR) loaded PHBHHx (poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)) nanoparticles as a novel and efficient drug delivery system. CUR is a promising anticancer agent for various cancer types. The aim of this study was to evaluate therapeutic potential of curcumin loaded PHBHHx nanoparticles (CUR-NPs) and concanavaline A conjugated curcumin loaded NPs (ConA-CUR NPs) for ovarian cancer treatment. ConA was covalently connected to the carboxylic group of nanoparticles by EDC/NHS activation method. In the ligand attachment experiment, the binding capacity of ConA on the surface of NPs was found about 90%. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis showed that the prepared nanoparticles were smooth and spherical in shape. The size and zeta potential of prepared NPs were about 228±5 nm and −21.3 mV respectively. ConA-CUR NPs were characterized by FT-IR spectroscopy which confirmed the existence of CUR and ConA in the nanoparticles. The entrapment and loading efficiencies of different polymer/drug weight ratios, 1/0.125 PHBHHx/CUR= 1.25CUR-NPs; 1/0.25 PHBHHx/CUR= 2.5CUR-NPs; 1/0.5 PHBHHx/CUR= 5CUR-NPs, ConA-1.25CUR NPs, ConA-2.5CUR NPs and ConA-5CUR NPs were found to be ≈ 68%-16.8%; 55%-17.7 %; 45%-33.6%; 70%-15.7%; 60%-17%; 51%-30.2% respectively. In vitro drug release showed that the sustained release of curcumin was observed from CUR-NPs and ConA-CUR NPs over a period of 19 days. After binding of ConA, the release rate was slightly increased due to the migration of curcumin to the surface of the nanoparticles and the matrix integrities was decreased because of the conjugation reaction. This functionalized nanoparticles demonstrated high drug loading capacity, sustained drug release profile, and high and long term anticancer efficacy in human cancer cell lines. Anticancer activity of ConA-CUR NPs was proved by MTT assay and reconfirmed by apoptosis and necrosis assay. The anticancer activity of ConA-CUR NPs was measured in ovarian cancer cells (SKOV-3) and the results revealed that the ConA-CUR NPs had better tumor cells decline activity than free curcumin. The nacked nanoparticles have no cytotoxicity against human ovarian carcinoma cells. Thus the developed functionalized nanoformulation could be a promising candidate in cancer therapy.

Keywords: curcumin, curcumin-PHBHHx nanoparticles, concanavalin A, concanavalin A-curcumin PHBHHx nanoparticles, PHBHHx nanoparticles, ovarian cancer cell

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Authors: Mohammad M. Khan, Gajendra Dixit

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Partially lubricated sliding wear behaviour of a zinc-based alloy reinforced with 10wt% SiC particles has been studied as a function of applied load and solid lubricant particle size and has been compared with that of matrix alloy and conventionally used grey cast iron. The wear tests were conducted at the sliding velocities of 2.1m/sec in various partial lubricated conditions using pin on disc machine as per ASTM G-99-05. Base oil (SAE 20W-40) or mixture of the base oil with 5wt% graphite of particle sizes (7-10 µm) and (100 µm) were used for creating lubricated conditions. The matrix alloy revealed primary dendrites of a and eutectoid a + h and Î phases in the Inter dendritic regions. Similar microstructure has been depicted by the composite with an additional presence of the dispersoid SiC particles. In the case of cast iron, flakes of graphite were observed in the matrix; the latter comprised of (majority of) pearlite and (limited quantity of) ferrite. Results show a large improvement in wear resistance of the zinc-based alloy after reinforcement with SiC particles. The cast iron shows intermediate response between the matrix alloy and composite. The solid lubrication improved the wear resistance and friction behaviour of both the reinforced and base alloy. Moreover, minimum wear rate is obtained in oil+ 5wt % graphite (7-10 µm) lubricated environment for the matrix alloy and composite while for cast iron addition of solid lubricant increases the wear rate and minimum wear rate is obtained in case of oil lubricated environment. The cast iron experienced higher frictional heating than the matrix alloy and composite in all the cases especially at higher load condition. As far as friction coefficient is concerned, a mixed trend of behaviour was noted. The wear rate and frictional heating increased with load while friction coefficient was affected in an opposite manner. Test duration influenced the frictional heating and friction coefficient of the samples in a mixed manner.

Keywords: solid lubricant, sliding wear, grey cast iron, zinc based metal matrix composites

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Authors: Raviv Harris, Maggie Levy

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Natural product-based pesticides may serve as an alternative to the traditional synthetic pesticides, which have a potentially damaging effect, both to human health and for the environment. Along with plants, microorganisms are a prospective source of such biological pesticides. A unique and active strain of P. aphidis (designated isolate L12, Israel 2004), an epiphytic and non-pathogenic basidiomycete yeast, was isolated in our lab from strawberry leaves. P. aphidis L12 secretions were found to inhibit broad range of plant pathogens. This work demonstrates that metabolites isolated from the biocontrol agent P. aphidis (isolate L12) can inhibit varied fungal and bacterial phytopathogens. Biologically active metabolites were extracted from P. aphidis biomass, using the organic solvent ethyl acetate. The antimicrobial activity of the extract was demonstrated, both in vitro and in planta. Using disk diffusion assays, the following inhibition zones were obtained: 43cm² for Pseudomonas syringae pv. tomato, 28.5cm² for Xanthomonas campestris pv. vesicatoria, 59cm² for Clavibacter michiganensis subsp. michiganensis, 34cm² for Erwinia amylovora and 34cm² for Agrobacterium tumefaciens. Additionally, strong inhibitory activity of the extract against fungi mycelial growth was established, with IC₅₀ values of 606µg ml⁻¹ for Botrytis cinerea, 221µg ml⁻¹ for Pythium spp., 519µg ml⁻¹ for Rhizoctonia solani, 455µg ml⁻¹ for Sclerotinia sclerotiorum, 2270µg ml⁻¹ for Fusarium oxysporum f. sp. lycopersici, and 2038µg ml⁻¹ for Alternaria alternata. The results of the in planta experiments demonstrated a dose-dependent reduction in disease infection. Significant inhibition of B. cinerea lesions on tomato plants was obtained when a spore suspension of this pathogen was treated with extract concentrations higher than 4.2mg ml⁻¹. Concentration of 7mg ml⁻¹ caused a reduction of over 95% in the lesion size of B. cinerea on tomato plants. The strong antimicrobial activity demonstrated both in vitro and in planta against varied phytopathogens, may indicate that the extracted antimicrobial metabolites have potential to serve as natural pesticides in the field.

Keywords: antimicrobial, B. cinerea, metabolites, natural pesticides, P. aphidis

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Authors: Guna Raj Dhungana, Roshan Nepal, Apshara Parajuli, , Archana Maharjan, Shyam K. Mishra, Pramod Aryal, Rajani Malla

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Introduction: Klebsiella pneumoniae is a well-known opportunistic human pathogen, primarily causing healthcare-associated infections. The global emergence of carbapenemase-producing K. pneumoniaeis a major public health burden, which is often extensively multidrug resistant.Thus, because of the difficulty to treat these ‘superbug’ and menace and some term as ‘apocalypse’ of post antibiotics era, an alternative approach to controlling this pathogen is prudent and one of the approaches is phage mediated control and/or treatment. Objective: In this study, we aimed to isolate novel bacteriophage against carbapenemase-producing K. pneumoniaeand characterize for potential use inphage therapy. Material and Methods: Twenty lytic phages were isolated from river water using double layer agar assay and purified. Biological features, physiochemical characters, burst size, host specificity and activity spectrum of phages were determined. One most potent phage: Phage TU_Kle10O was selected and characterized by electron microscopy. Whole genome sequences of the phage were analyzed for presence/absence of virulent factors, and other lysin genes. Results: Novel phage TU_Kle10O showed multiple host range within own genus and did not induce any BIM up to 5th generation of host’s life cycle. Electron microscopy confirmed that the phage was tailed and belonged to Caudovirales family. Next generation sequencing revealed its genome to be 166.2 Kb. bioinformatical analysis further confirmed that the phage genome ‘did not’ contain any ‘bacterial genes’ within phage genome, which ruled out the concern for transfer of virulent genes. Specific 'lysin’ enzyme was identified phages which could be used as 'antibiotics'. Conclusion: Extensively multidrug resistant bacteria like carbapenemase-producing K. pneumoniaecould be treated efficiently by phages.Absence of ‘virulent’ genes of bacterial origin and presence of lysin proteins within phage genome makes phages an excellent candidate for therapeutics.

Keywords: bacteriophage, Klebsiella pneumoniae, MDR, phage therapy, carbapenemase,

Procedia PDF Downloads 190

Authors: Tanios Saliba, Jad Wakim, Elie Awwad

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Clayey soils exhibit undesirable problems in civil engineering project: poor bearing soil capacity, shrinkage, cracking, …etc. On the other hand, the increasing production of bottom ash and its disposal in an eco-friendly manner is a matter of concern. Soil stabilization using bottom ash is a new technic in the geo-environmental engineering. It can be used wherever a soft clayey soil is encountered in foundations or road subgrade, instead of using old technics such as cement-soil mixing. This new technology can be used for road embankments and clayey foundations platform (shallow or deep foundations) instead of replacing bad soil or using old technics which aren’t eco-friendly. Moreover, applying this new technic in our geotechnical engineering projects can reduce the disposal of the bottom ash problem which is getting bigger day after day. The research consists of mixing clayey soil with different percentages of bottom ash at different values of water content, and evaluates the mechanical properties of every mix: the percentages of bottom ash are 10% 20% 30% 40% and 50% with values of water content of 25% 35% and 45% of the mix’s weight. Before testing the different mixes, clayey soil’s properties were determined: Atterbeg limits, soil’s cohesion and friction angle and particle size distribution. In order to evaluate the mechanical properties and behavior of every mix, different tests are conducted: -Direct shear test in order to determine the cohesion and internal friction angle of every mix. -Unconfined compressive strength (stress strain curve) to determine mix’s elastic modulus and compressive strength. Soil samples are prepared in accordance with the ASTM standards, and tested at different times, in order to be able to emphasize the influence of the curing period on the variation of the mix’s mechanical properties and characteristics. As of today, the results obtained are very promising: the mix’s cohesion and friction angle vary in function of the bottom ash percentage, water content and curing period: the cohesion increases enormously before decreasing for a long curing period (values of mix’s cohesion are larger than intact soil’s cohesion) while internal friction angle keeps on increasing even when the curing period is 28 days (the tests largest curing period), which give us a better soil behavior: less cracks and better soil bearing capacity.

Keywords: bottom ash, Clayey soil, mechanical properties, tests

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Authors: S. K. Verma, S. L. Sinha, D. K. Chandraker

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The Advanced Heavy Water Reactor (AHWR) is a vertical pressure tube type, heavy water moderated and boiling light water cooled natural circulation based reactor. The fuel bundle of AHWR contains 54 fuel rods arranged in three concentric rings of 12, 18 and 24 fuel rods. This fuel bundle is divided into a number of imaginary interacting flow passage called subchannels. Single phase flow condition exists in reactor rod bundle during startup condition and up to certain length of rod bundle when it is operating at full power. Prediction of the thermal margin of the reactor during startup condition has necessitated the determination of the turbulent mixing rate of coolant amongst these subchannels. Thus, it is vital to evaluate turbulent mixing between subchannels of AHWR rod bundle. With the remarkable progress in the computer processing power, the computational fluid dynamics (CFD) methodology can be useful for investigating the thermal–hydraulic characteristics phenomena in the nuclear fuel assembly. The present report covers the results of simulation of pressure drop, velocity variation and turbulence intensity on single rod bundle with 54 rods in circular arrays. In this investigation, 54-rod assemblies are simulated with ANSYS Fluent 15 using steady simulations with an ANSYS Workbench meshing. The simulations have been carried out with water for Reynolds number 9861.83. The rod bundle has a mean flow area of 4853.0584 mm2 in the bare region with the hydraulic diameter of 8.105 mm. In present investigation, a benchmark k-ε model has been used as a turbulence model and the symmetry condition is set as boundary conditions. Simulation are carried out to determine the turbulent mixing rate in the simulated subchannels of the reactor. The size of rod and the pitch in the test has been same as that of actual rod bundle in the prototype. Water has been used as the working fluid and the turbulent mixing tests have been carried out at atmospheric condition without heat addition. The mean velocity in the subchannel has been varied from 0-1.2 m/s. The flow conditions are found to be closer to the actual reactor condition.

Keywords: AHWR, CFD, single-phase turbulent mixing rate, thermal–hydraulic

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Authors: K. Tesfamariam, S. Gebreyesus, C. Lachat, P. Kolsteren, S. De Saeger, M. De Boevre, A. Argaw

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Aflatoxins are toxic secondary metabolites produced by Aspergillus fungi, which are ubiquitously present in the food supplies of low- and middle-income countries. Studies of maternal aflatoxin exposure and fetal outcomes are mainly focused on size at birth and the effect on intrauterine fetal growth has not been assessed using repeated longitudinal fetal biometry across gestation. Therefore, this study intends to assess the association between chronic aflatoxin exposure during pregnancy and fetal growth trajectories in a rural Ethiopian setting. In a prospective cohort study, we enrolled 492 pregnant women. A phlebotomist collected 5 mL of a venous blood sample from eligible women before 28 completed weeks of gestation and aflatoxin B1-lysine concentration was determined using liquid chromatography-tandem mass spectrometry. The mean (±SD) gestational age was 19.1 (3.71) weeks at enrollment, and 28.5 (3.51) and 34.5 (2.44) weeks of gestation at the second and third rounds of ultrasound measurements, respectively. Estimated fetal weight was expressed in centiles using the INTERGROWTH-21st reference. We fitted a multivariable linear mixed-effects model to estimate the rate of fetal growth between aflatoxin-exposed (i.e., aflatoxin B1-lysine concentration above or equal to the limit of detection) and non-exposed mothers in the study. Mothers had a mean (±SD) age of 26.0 (4.58) years. The median (P25, P75) serum AFB1-lysine concentration was 12.6 (0.93, 96.9) pg/mg albumin, and aflatoxin exposure was observed in 86.6% of maternal blood samples. Eighty-five percent of the women enrolled provided at least two ultrasound measurements for analysis. On average, the aflatoxin-exposed group had a significantly lower change over time in fetal weight-for-gestational age centile than the unexposed group (ß = -1.01 centiles/week, 95% CI: -1.87, -0.15, p = 0.02). Chronic maternal AF exposure is associated with lower fetal weight gain over time. Our findings emphasize the importance of nutrition-sensitive strategies to mitigate dietary aflatoxin exposure as well as adopting food safety measures in low-income settings, particularly during the fetal period of development.

Keywords: aflatoxin, fetal growth, low-income setting, mycotoxins

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Authors: Ardiana Murtezani, Ilirijana Dallku, Teuta Osmani Vllasolli, Sabit Sllamniku

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Background: The use of foot orthoses are always indicated when there are alterations of the optimal biomechanics' position of the foot. Orthotics are very effective and very suitable for the majority of patients with pain due to overload which can be related to biomechanical disorders. Aim: To assess the frequency of patients requiring foot orthoses, type of orthoses and analysis of their disease leading to the use of foot orthoses. Material and Methods: Our study included 128 patients with various foot pathologies, treated at the outpatient department of the Ortho-Prosthetic Center of Kosovo (OPCK) in Prishtina. Prospective-descriptive clinical method was used during this study. Functional status of patients was examined, and the following parameters are noted: range of motion measurements for the affected joints/lower extremities, manual test for muscular strength below the knee and foot of the affected extremity, perimeter measurements of the lower extremities, measurements of lower extremities, foot length measurement, foot width measurements and size. In order to complete the measurements the following instruments are used: plantogram, pedogram, meter and cork shoe lift appliances. Results: The majority of subjects in this study are male (60.2% vs. 39.8%), and the dominant age group was 0-9 (47.7%), 61 subjects respectively. Most frequent foot disorders were: congenital disease 60.1%, trauma cases 13.3%, consequences from rheumatologic disease 12.5%, neurologic dysfunctions 11.7%, and the less frequented are the infectious cases 1.6%. Congenital anomalies were the most frequent cases, and from this group majority of cases suffered from pes planovalgus (37.5%), eqinovarus (15.6%) and discrepancies between extremities (6.3%). Furthermore, traumatic amputations (2.3%) and arthritis (0.8%). As far as neurologic disease, subjects with cerebral palsy are represented with (3.1%), peroneal nerve palsy (2.3%) and hemiparesis (1.6%). Infectious disease osteomyelitis sequels are represented with (1.6%). Conclusion: Based on our study results, we have concluded that the use of foot orthoses for patients suffering from rheumatoid arthritis and nonspecific arthropaty was effective treatment choice, leading to decrease of pain, less deformities and improves the quality of life.

Keywords: orthoses, epidemiological analysis, rheumatoid arthritis, rehabilitation

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Authors: Ezman Fitriansyah, Lestari Diah Restu, Wawan

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Adaro coal mine in South Kalimantan-Indonesia maintains catchment area of approximately 15,000 Ha for its mine operation. As an open pit surface coal mine with high erosion rate, the mine water in Adaro coal mine contains high TSS that needs to be treated before being released to rivers. For the treatment process, Adaro operates 21 Settling Ponds equipped with combination of physical and chemical system to separate solids and water to ensure the discharged water complied with regional environmental quality standards. However, the sludge created from the sedimentation process reduces the settling ponds capacity gradually. Therefore regular maintenance activities are required to recover and maintain the ponds' capacity. Trucking system and direct dredging had been the most common method to handle sludge in Adaro. But the main problem in applying these two methods is excessive area required for drying pond construction. To solve this problem, Adaro implements an alternative method called Geotube®. The principle of Geotube® method is the sludge contained in the Settling Ponds is pumped into Geotube® containers which have been designed to release water and retain mud flocks. During the pumping process, an amount of flocculants chemicals are injected into the sludge to form bigger mud flocks. Due to the difference in particle size, the mud flocks are settled in the container whilst the water continues to flow out through the container’s pores. Compared to the trucking system and direct dredging method, this method provides three advantages: space required to operate, increasing of overburden waste dump volume, and increasing of water treatment process speed and quality. Based on the evaluation result, Geotube® method only needs 1:8 of space required by the other methods. From the geotechnical assessment result conducted by Adaro, the potential loss of waste dump volume capacity prior to implementation of the Geotube® method was 26.7%. The water treatment process of TSS in well maintained ponds is 16% more optimum.

Keywords: geotube, mine water, settling pond, sludge handling, wastewater treatment

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Authors: Florenda B. Cardinoza

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This study was conducted to determine the determinants of Grade III and grade VI pupils’ performance in the National Achievement Test in the Division of Cavite City, School Year 2011-2012. Specifically, the research aimed to: (1) describe the demographic profile of the respondents in terms of age, sex, birth order, family size, family income, and occupation of parents; (2) determine the level of attitude towards NAT; and (3) describe the degree of relationship between the following variables: school support, teachers’ support, and lastly family support for the pupils’ performance in 2012 NAT. The study used the descriptive-correlation research method to investigate the determinants of pupils’ performance in the National Achievement Test of Public Elementary Schools in the Division of Cavite City. The instrument used in data gathering was a self-structured survey. The NAT result for SY 2011-2012 provided by NETRC and DepEd Cavite City was also utilized. The statistical tools used to process and analyze the data were frequency distribution, percentage, mean, standard deviation, Kruskall Wallis, Mann-Whitney, t-test for independent samples, One-way ANOVA, and Spearman Rank Correlational Coefficient. Results revealed that there were more female students than males in the Division of Cavite City; out of 659 respondents, 345 were 11 years old and above; 390 were females; 283 were categorized as first child in the family; 371 of the respondents were from small family; 327 had Php5000 and below family income; 450 of the fathers’ respondents were non professionals; and 431 of the mothers respondents had no occupation. The attitude towards NAT, with a mean of 1.65 and SD of .485, shows that respondents considered NAT important. The school support towards NAT, with a mean of 1.89 and SD of .520, shows that respondents received school support. The pupils had a very high attitude towards teachers’ support in NAT with a mean of 1.60 and SD of .572. Family support, with t-test of 16.201 with a p-value of 0.006, shows significant at 5 percent level. Thus, the determinants of pupils’ performance in NAT in terms of family support for NAT preparation is not significant according to their family income. The grade level, with the t-test is 4.420 and a p-value of 0.000, is significant at 5 percent level. Therefore, the determinants of pupils’ performance in NAT in terms of grade level for NAT preparation vary according to their grade level. For the determinants of pupils’ performance of NAT sample test for attitude towards NAT, school support, teachers’ support, and family support were noted highly significant with a p value of 0.000.

Keywords: achievement, determinants, national, performance, public, pupils', test

Procedia PDF Downloads 350

Authors: Solene Masloh, Anne Chevrel, Maxime Culot, Leonardo Scapozza, Magali Zeisser-Labouebe

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The limited stability of clinically proven therapeutic antibodies limits their administration by the parenteral route. However, oral administration remains the best alternative as it is the most convenient and less invasive one. Obtaining a targeted treatment based on biologics, which can be orally administered, would, therefore, be an ideal situation to improve patient adherence and compliance. Nevertheless, the delivery of macromolecules through the intestine remains challenging because of their sensitivity to the harsh conditions of the gastrointestinal tract and their low permeability across the intestinal mucosa. To address this challenge, this project aims to demonstrate that targeting receptor-mediated endocytosis followed by transcytosis could maximize the intestinal uptake and transport of large molecules, such as Nanofitins. These affinity proteins of 7 kDa with binding properties similar to antibodies have already demonstrated retained stability in the digestive tract and local efficiency. However, their size does not allow passive diffusion through the intestinal barrier. Nanofitins having a controlled affinity for membrane receptors involved in the transcytosis mechanism used naturally for the transport of large molecules in humans were generated. Proteins were expressed using ribosome display and selected based on affinity to the targeted receptor and other characteristics. Their uptake and transport ex vivo across viable porcine intestines were investigated using an Ussing chambers system. In this paper, we will report the results achieved while addressing the different challenges linked to this study. To validate the ex vivo model, first, we proved the presence of the receptors targeted in humans on the porcine intestine. Then, after the identification of an optimal way of detection of Nanofitins, transport experiments were performed on porcine intestines with viability followed during the time of the experiment. The results, showing that the physiological process of transcytosis is capable of being triggered by the binding of Nanofitins on their target, will be reported here. In conclusion, the results show that Nanofitins can be transported across the intestinal barrier by triggering the receptor-mediated transcytosis and that the ex vivo model is an interesting technique to assess biologics absorption through the intestine.

Keywords: ex-vivo, Nanofitins, oral administration, transcytosis

Procedia PDF Downloads 178

Authors: Henok Yebyo Henok, Araya Abrha Araya, Alemayehu Bayray Alemayehu, Gelila Goba Gelila

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Background: Every year, an estimated 19–20 million unsafe abortions take place, almost all in developing countries, leading to 68,000 deaths and millions more injured many permanently. Many women throughout the world, experience more than one abortion in their lifetimes. Repeat abortion is an indicator of the larger problem of unintended pregnancy. This study aimed to identify determinants of repeat abortion in Tigray Region, Ethiopia. Methods: Unmatched case-control study was conducted in hospitals in Tigray Region, Northern Ethiopia, from November 2014 to June 2015. The sample included 105 cases and 204 controls, recruited from among women seeking abortion care at public hospitals. Clients having two or more abortions (“repeat abortion”) were taken as cases, and those who had a total of one abortion were taken as controls (“single abortion”). Cases were selected consecutive based on proportional to size allocation while systematic sampling was employed for controls. Data were analyzed using SPSS version 20.0. Binary and multiple variable logistic regression analyses were calculated with 95% CI. Results: Mean age of cases was 24 years (±6.85) and 22 years (±6.25) for controls. 79.0% of cases had their sexual debut in less than 18 years of age compared to 57% of controls. 42.2% of controls and 23.8% of cases cited rape as the reason for having an abortion. Study participants who did not understand their fertility cycle and when they were most likely to conceive after menstruation (adjusted odds ratio [AOR]=2.0, 95% confidence interval [CI]: 1.1-3.7), having a previous abortion using medication(AOR=3.3, CI: 1.83, 6.11), having multiple sexual partners in the preceding 12 months (AOR=4.4, CI: 2.39,8.45), perceiving that the abortion procedure is not painful (AOR=2.3, CI: 1.31,4.26), initiating sexual intercourse before the age of 18 years (AOR=2.7, CI: 1.49, 5.23) and disclosure to a third-party about terminating the pregnancy (AOR=2.1, CI: 1.2,3.83) were independent predictors of repeat abortion. Conclusion: This study identified several factors correlated with women having repeat abortions. It may be helpful for the Government of Ethiopia to encourage women to delay sexual debut and decrease their number of sexual partners, including by promoting discussion within families about sexuality, to decrease the occurrence of repeated abortion.

Keywords: abortion, Ethiopia, repeated abortion, single abortion

Procedia PDF Downloads 286

Authors: Maatouk Khoukhi

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Nowadays the reduction of the energy consumed by buildings to achieve mainly the thermal comfort for the occupants represent the main concern for architects and building designers. The common and traditional solution to achieve this target is the design of a highly insulated envelope and reduce the opening and the transparent elements such windows. However, this will lead to the artificial lighting system to consume more energy to compensate the lack of natural lighting coming through the glazed parts of the building envelope. Therefore, a good balance between sufficient daylight and control thermal heat through the building envelope should be considered for energy saving purpose. To achieve a better indoor environment the windows size and spacing including the interior finishing and the location of the partition must be assessed accurately. Daylighting is the controlled admission of natural light into space through windows and transparent elements of the building envelope which helps create a visually stimulating and productive environment for building occupants. The main concern is not to provide enough daylight to an occupied space, but how to achieve this without any undesirable side effect. Indeed, the glare is a major problem in glazed façade buildings, and this could be reduced by using tinted windows. The main target of this research is to investigate the daylight adequacy of functional needs in old Omani Forts and how they have been designed and built to avoid glare and overheating with the appropriate window-to-floor ratio. Because more windows do not automatically result in more daylighting but that is natural light has been controlled and distributed properly throughout the space. Spaces from different Omani and Portuguese Forts under the same climate conditions are considered in order to compare the daylight illuminance levels and examine the similarities and differences in visual attributes between them. The result of this study indicates that lighting preference is not universal and people from different geographical locations are adapted to certain illuminance levels. Therefore, the standards could not be generalized for the entire world. This would be useful to practitioners who are designing to effectively address the diversity of user’s lighting levels preferences in our globally connected society.

Keywords: day lighting, energy, forts, thermal comfort

Procedia PDF Downloads 167

Authors: M. Areekijseree, W. Pongsawat, M. Pumipaiboon, C. Thepsithar, S. Sengsai, T. Chuen-Im

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Morphological interaction of porcine cumulus-oocyte complexes (pCOCs) was investigated on in vitro condition using electron microscope (SEM and TEM). The totals of 1,923 oocytes were round in shape, surrounded by zona pellucida with layer of cumulus cells ranging between 59.29-202.14 µm in size. They were classified into intact-, multi-, partial cumulus cell layer oocyte, and completely denuded oocyte, at the percentage composition of 22.80% 32.70%, 18.60%, and 25.90 % respectively. The pCOCs classified as intact- and multi cumulus cell layer oocytes were further culturing at 37°C with 5% CO2, 95% air atmosphere and high humidity for 44 h in M199 with Earle’s salts supplemented with 10% HTFCS, 2.2 mg/mL NaHCO3, 1 M Hepes, 0.25 mM pyruvate, 15 µg/mL porcine follicle-stimulating hormone, 1 µg/mL LH, 1µg/mL estradiol with ethanol, and 50 µg/mL gentamycin sulfate. On electron microscope study, cumulus cells were found to stick their processes to secrete substance from the sac-shape end into zona pellucida of the oocyte and also communicated with the neighboring cells through their microvilli on the beginning of incubation period. It is believed that the cumulus cells communicate with the oocyte by inserting the microvilli through this gap and embedded in the oocyte cytoplasm before secreting substance, through the sac-shape end of the microvilli, to inhibit primary oocyte development at the prophase I. Morphological changes of the complexes were observed after culturing for 24-44 h. One hundred percentages of the cumulus layers were expanded and cumulus cells were peeling off from the oocyte surface. In addition, the round-shape cumulus cells transformed themselves into either an elongate shape or a columnar shape, and no communication between cumulus neighboring cells. After 44 h of incubation time, diameter of oocytes surrounded by cumulus cells was larger than 0 h incubation. The effect of hormones in culture medium is exerted by their receptors present in porcine oocyte. It is likely that all morphological changes of the complexes after hormone treatment were to allow maturation of the oocyte. This study demonstrated that the association of hormones in M199 could promote porcine follicle activation in 44 h in vitro condition. This culture system should be useful for studying the regulation of early follicular growth and development, especially because these follicles represent a large source of oocytes that could be used in vitro for cell technology.

Keywords: cumulus cells, electron microscopy, in vitro, porcine oocyte

Procedia PDF Downloads 385

Authors: Minho Lee, Donghyun Back, Jaemoon Jung, Woojin Park

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The current 3-dimensional (3D) posture prediction models commonly provide only a few optimal postures to achieve a specific objective. The problem with such models is that they are incapable of rapidly providing several optimal posture candidates according to various situations. In order to solve this problem, this paper presents a 3D memory-based posture planning (3D MBPP) model, which is a new digital human model that can analyze the feasible postures in 3D space for reaching tasks that have postural constraints and specific reaching space. The 3D MBPP model can be applied to the types of works that are done with constrained working postures and have specific reaching space. The examples of such works include driving an excavator, driving automobiles, painting buildings, working at an office, pitching/batting, and boxing. For these types of works, a limited amount of space is required to store all of the feasible postures, as the hand reaches boundary can be determined prior to perform the task. This prevents computation time from increasing exponentially, which has been one of the major drawbacks of memory-based posture planning model in 3D space. This paper validates the utility of 3D MBPP model using a practical example of analyzing baseball batting posture. In baseball, batters swing with both feet fixed to the ground. This motion is appropriate for use with the 3D MBPP model since the player must try to hit the ball when the ball is located inside the strike zone (a limited area) in a constrained posture. The results from the analysis showed that the stored and the optimal postures vary depending on the ball’s flying path, the hitting location, the batter’s body size, and the batting objective. These results can be used to establish the optimal postural strategies for achieving the batting objective and performing effective hitting. The 3D MBPP model can also be applied to various domains to determine the optimal postural strategies and improve worker comfort.

Keywords: baseball, memory-based, posture prediction, reaching area, 3D digital human models

Procedia PDF Downloads 216

Authors: Estelle Démoulin, Dionysios Adamopoulos, Tornike Sologashvili, Mathieu Van Steenberghe, Jalal Jolou, Haran Burri, Christoph Huber, Mustafa Cikirikcioglu

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Background & objective: Mitral valve surgeries are mainly performed by median sternotomy with conventional direct atriotomy. Good exposure to the mitral valve is challenging, especially for acute pathologies, where left atrium dilation does not occur. Other atriotomies, such as transseptal or superior septal, are used as they allow better access and visualization. Peri- and postoperative outcomes of these three different left atriotomies were compared. Methods: Patients undergoing mitral valve surgery between January 2010 and December 2020 were included and divided into three groups: group 1 (conventional direct, n=115), group 2 (transseptal, n=33) and group 3 (superior septal, n=59). To improve the sampling size, all patients underwent mitral valve surgery with or without associated procedures (CABG, aortic-tricuspid surgery, Maze procedure). The study protocol was approved by SwissEthics. Results: No difference was shown for the etiology of mitral valve disease, except endocarditis, which was more frequent in group 3 (p = 0.014). Elective surgeries and isolated mitral valve surgery were more frequent in group 1 (p = 0.008, p = 0.011) and aortic clamping and cardiopulmonary bypass were shorter (p = 0.002, p<0.001). Group 3 had more emergency procedures (p = 0.011) and longer lengths of intensive care unit and hospital stay (p = 0.000, p = 0.003). There was no difference in permanent pacemaker implantation, postoperative complications and mortality between the groups. Conclusion: Mitral valve surgeries can be safely performed using those three left atriotomies. Conventional direct may lead to shorter aortic clamping and cardiopulmonary bypass times. Superior septal is mostly used for acute pathologies, and it does not increase postoperative arrhythmias and permanent pacemaker implantation. However, intensive care unit and hospital lengths of stay were found to be longer in this group. In our opinion, this outcome is more related to the pathology and type of surgery than the incision itself.

Keywords: Mitral valve surgery, cardiac surgery, atriotomy, Operative outcomes

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Authors: Anne Waithira Dormal

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Climate change is threatening pastoral livelihoods in Kajiado County, Kenya, through water shortages, livestock deaths, and increasing poverty. This study examines how these impacts differ for men and women within these communities. Limited access to resources, limited land and livestock rights, and limited decision-making power increase women's vulnerability, which is further burdened by traditional gender roles in water procurement. The research recognizes the complexity of climate change and emphasizes that factors such as wealth, family dynamics, and socioeconomic status also influence resilience. Effective adaptation strategies must address all genders. While livestock farming provides a safety net, socioeconomic empowerment through access to credit, healthcare, and education strengthens entire communities. An intersectional perspective that takes ethnicity, social status, and other factors into account is also crucial. This research, therefore, aims to examine how gender-specific adaptation strategies interact with gender and socioeconomic factors to determine the resilience of these Kenyan pastoralist communities. Such strategies, which address the specific needs and vulnerabilities of men and women, are expected to lead to increased resilience to climate change. The aim of the study is to identify effective, gender-specific adaptation strategies that can be integrated into climate change planning and implementation. Additionally, research awaits a deeper understanding of how socioeconomic factors interact with gender to influence vulnerability and resilience within these communities. The study uses a gender-sensitive qualitative approach with focus group discussions in four different pastoral and agropastoral communities. Both qualitative and demographic data are used to capture sources of income, education level, and household size of focus group respondents to increase the power of the analysis. While the research acknowledges the limitations of specific focus sites and potential biases in self-reporting, it offers valuable insights into gender and climate change in pastoral contexts. This study contributes to understanding gender-based vulnerabilities and building resilience in these communities.

Keywords: climate adaptation strategies, climate change, climate resilience, gendered vulnerability, pastoralism

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Authors: Eronini Iheanyi Umez-Eronini

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Most studies and existing implementations of compressed air energy storage (CAES) coupled with a wind farm to overcome intermittency and variability of wind power are based on bulk or centralized CAES plants. A dynamic model of a hybrid wind farm with wind turbines and distributed CAES, consisting of air storage tanks and compressor and expander trains at each wind turbine station, is developed and simulated in MATLAB. An ad hoc supervisory controller, in which the wind turbines are simply operated under classical power optimizing region control while scheduling power production by the expanders and air storage by the compressors, including modulation of the compressor power levels within a control range, is used to regulate overall farm power production to track minute-scale (3-minutes sampling period) TSO absolute power reference signal, over an eight-hour period. Simulation results for real wind data input with a simple wake field model applied to a hybrid plant composed of ten 5-MW wind turbines in a row and ten compatibly sized and configured Diabatic CAES stations show the plant controller is able to track the power demand signal within an error band size on the order of the electrical power rating of a single expander. This performance suggests that much improved results should be anticipated when the global D-CAES control is combined with power regulation for the individual wind turbines using available approaches for wind farm active power control. For standalone power plant fuel electrical efficiency estimate of up to 60%, the round trip electrical storage efficiency computed for the distributed CAES wherein heat generated by running compressors is utilized in the preheat stage of running high pressure expanders while fuel is introduced and combusted before the low pressure expanders, was comparable to reported round trip storage electrical efficiencies for bulk Adiabatic CAES.

Keywords: hybrid wind farm, distributed CAES, diabatic CAES, active power control, dynamic modeling and simulation

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Authors: E. T. Svahn

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Knowledge about the factors that influence the exchange between research and society is of the utmost importance for developing collaboration between different actors, especially in future science policy development and the creation of support structures for researchers. Among other things, how researchers look at the surrounding open science policy environment and what conditions and attitudes they have for interacting with it. This paper examines the Finnish researchers' attitudes towards open science policies in 2020. Open science is an integrated part of researchers' daily lives and supports not only the effectiveness of research outputs but also the quality of research. Open science policy in ideal situation is seen as a supporting structure that enables the exchange between research and society, but in other situation, it can end up being red tape generating obstacles and hindering possibilities of making science in an efficient way. Results of this study were carried out through focus group interviews. This qualitative research method was selected because it aims to understand the phenomenon under study. In addition, focus group interviews produce diverse and rich material that would not be available with other research methods. Focus group interviews have well-established applications in social science, especially in understanding the perspectives and experiences of research subjects. In this study, focus groups were used in studying the mindset and actions of researchers. Each group's size was between 4-10 people, and the aim was to bring out different perspectives on the subject. The interviewer enabled the presentation of different perceptions and opinions, and the focus group interviews were recorded and written as text. The material was analysed using grounded theory method. The results are presented as thematic areas, theoretical model, and as direct quotations. Attitudes towards open science policy can vary greatly depending on the research area. This study shows that the open science policy demands in medicine, technology, and natural sciences compared to social sciences, educational sciences, and the humanities, varies somewhat. The variation in attitudes between different research areas can thus be largely explained by the fact that the research output and ethical code vary significantly between certain subjects. This study aims to increase understanding of the nuances to what extent open science policies should be tailored for different disciplines and research areas.

Keywords: focus group interview, grounded theory, open science policy, science policy

Procedia PDF Downloads 155