Search results for: soil physical properties

Authors: Ryu Wonjin, Choi Hyeok, Park Joonhong

Abstract:

Overlay welding for improving surface properties is a method of the surface treatments which improve surface properties of material by welding materials of alloy having corrosion resistance on the basic material surface. Overlay welding affects contents of chemical components and weld hardness from different parts by dilution of the lamination layer thickness, and it determines surface properties. Therefore, overlay welding has to take into account thickness of the lamination layers with the process. As a result in this study examined contents of Fe, weldability of the base metal and monel materials, hardness and surface flatness from different parts according to each the lamination layer parameters by overlay welding monel materials with corrosion resources to the base material of carbon steel. Through this, evaluated effect by the lamination layer parameters of welding and presented decision methods of the lamination layer parameters of the overlay welding by the purpose of use.

Keywords: clad pipe, lamination layer parameters, monel, overlay welding

Procedia PDF Downloads 249

Authors: Bernd Engel, Hassan Raheem Hassan

Abstract:

Rotary draw bending is a method used for tube forming. During the tube bending process, the neutral axis moves towards the inner arc and the wall thickness changes in the cross section of the tube. Wall thinning of the tube takes place at the extrados, whereas wall thickening of the tube occurs at the intrados. This paper investigates the tube bending with rotary draw bending process using thick-walled tubes and different material properties (16Mo3 and 10CrMo9-10). The experimental tests and finite element simulations are used to calculate the variable characteristics (wall thickness distribution, neutral axis shifting and longitudinal strain distribution). These results are compared with results of a plasto-mechanical model. Moreover, the cross section distortion is investigated in this study. This study helped to get bends with smaller wall factor for different material properties.

Keywords: rotary draw bending, thick wall tube, material properties, material influence

Procedia PDF Downloads 591

Authors: O. Phewnil, S. Khowhit, W. Inkapatanakul, A. Boutson, K. Chunkao, O. Chueawong, T. Pattamapitoon, N. Chanwong, C. Nimpee

Abstract:

The King’s Royally Initiated Laem Phak Bia Environmental Research and Development Project (“the Royal LERD Project”) is located in Laem Phak Bia Sub-District, Ban Laem District, Phetchaburi Province, Thailand. Phetchaburi municipal wastewater was treated with a simple technology by using aquatic plants, constructed wetland, oxidation ponds through a nature-by-nature process. The effluent from the Royal LERD Project was discharged into Laem Phak Bia muddy beach. The soil sediment samples were collected from two zones (200 and 600 meters from the coast of the beach), and tested for cation-exchange capacity (CEC), pH and organic matter and soil particles content. The marine water samples were also collected from the beach in wet and dry seasons and analyzed for its quality and compositions, including but not limited to, biochemical oxygen demand (BOD), dissolved oxygen (DO), suspended solids (SS), nutrients, heavy metals (As, Cd, Cr, Hg, and Pb), and phytoplankton at high and low tides. The soil texture was sandy loam with high concentration of calcium and magnesium which showed a property of base (pH 8). The marine water was qualified with the standard limits of coastal water quality. A dominant species was Coscinodiscus sp. It was found approximately 70.46% of total phytoplankton species in Meretrix casta gastrointestinal tract. The concentration of the heavy metals (As, Cd, Cr, Hg, Ni and Pb) in the tissues and water content of two species of hard clams indicated that heavy metals in Meretrix casta were higher than those in Meretrix meretrix. However, the heavy metals in both species were under the standard limits and safe for consumption. It can be concluded that nutrients in effluent from the wastewater treatment systems play important role in promoting the growth of phytoplankton and generating abundance of hard clams on muddy beach.

Keywords: wastewater, phytoplankton, hard clam (Meretrix spp.), muddy beach

Procedia PDF Downloads 277

Authors: Omar bin Mihat

Abstract:

The number of sudden deaths is increasing over the past years. These deaths occur not during physical activities but upon cessation. Post-mortem confirms these deaths as cardiac arrest non-specifically. Congenital heart disease is a condition undiagnosed whereby only surface upon physical exertion leading to sudden death is unavoidable. Channelopathy, a condition that refers to any disease from the defect in iron-channel function, particularly the sodium-potassium pump, during the cessation of the exercise can be controlled. The derivation of heart rate return (HRrtn) is a procedure of a control cooling down process according to the heart rate (HR). Empirically, potassium rises linearly with intensity and falls sharply upon abrupt cessation of exertion, resulting in fatal arrhythmia due to hypokalaemia. It is vital that the flux of potassium should be maintained within the normal range during physical activities. To achieve this, the dosage of physical exertion (exercise) should be identified. Various percentages of the intensity of maximum heart rate (MHR) will precipitate different adaptations and remodeling of various organs. 70% of MHR will surface physiological adaptations, including enhancement of endurance, fitness level, and general health, and there was no significant rise of serum potassium (K+) during the entire phase of the treadmill brisk walk at a different rate of perceived exertion (RPE) from the subject of various fitness background. There was also no significant rise in blood pressure (BP) during the entire phase of the treadmill brisk walk, substantiating 70% MHR is the safe dosage across different parameters of health and fitness level.

Keywords: potassium, maximal heart rate, exercise dosage, fitness level

Procedia PDF Downloads 46

Authors: Alaa A. Ghanem, S. E. M. Desouky

Abstract:

Natural gas (NG) is considered one of the most essential global energy sources. NG fields are often far away from the market, and a long-distance transporting pipeline usually is required. Production of NG with high content of CO₂ leads to severe problems such as equipment corrosion along with the production line until refinery.in addition to a high level of toxicity and decreasing in calorific value of the NG. So it is recommended to remove or decrease the CO₂ percent to meet transport specifications. This can be reached using different removal techniques such as physical and chemical absorption, pressure swing adsorption, membrane separation, or low-temperature separation. Many solvents and chemicals are being used to capture carbon dioxide on a large scale; among them, Ionic liquids have great potential due to their tunable properties; low vapour pressure, low melting point, and sensible thermal stability. In this research, three modifiedimidazolium ionic liquids will be synthesized and characterized using different tools of analysis such as FT-IR, 1H NMR. Thermal stability and surface activity will be studied. The synthesized compounds will be evaluated as selective solvents for CO₂ removal from natural gas using PVT cell.

Keywords: natural gas, CO₂ capture, imidazolium ionic liquid, PVT cell

Procedia PDF Downloads 156

Authors: Julie Wittmannová, Petr Šeda

Abstract:

Quality of life measurements (QLF) help to evaluate interventions programs in different groups of persons with special needs. Our presentation deals with QLF of persons with addiction in relation to the physical activity (PA), type of addiction, age, gender and other variables. The aim of presentation is to summarize the basic findings and offer thoughts for questions arose. Methods: SQUALA (Subjective Quality of Life Analysis); SEIQoL (Schedule for the Evaluation of Individual Quality of Life); questionnaire of own construction. The results are evaluated by Mann­Whitney U test and Kruskall­Wallis ANOVA test (p ≤ 0,05). Sample of 64 participants – clients of aftercare center, aged 18 plus. Findings: Application of the methods SQUALA and SEIQoL in the chosen population seems appropriate, the obtaining information regarding the QLF correlate to intervention program topics, the need of an activelifestyle and health related topics in persons with addiction is visible. Conclusions or Implications: The subjective evaluation of quality of life of Aftercare clients is an important part of evaluation process, especially used to evaluate satisfaction with offered services and programs. Techniques SQUALA and SEIQoL gave us the desired outcomes.

Keywords: adapted physical activity, addiction, quality of life, physical activity, aftercare

Procedia PDF Downloads 309

Authors: Juan F. P. Ramírez, Jésica A. L. Isaza, Benjamín A. Rojano

Abstract:

This study proposes a novel use of a method to determine the mechanical properties of fruits by the use of the indentation tests. The method combines experimental results with a numerical finite elements model. The results presented correspond to a simplified numerical modeling of banana. The banana was assumed as one-layer material with an isotropic linear elastic mechanical behavior, the Young’s modulus found is 0.3Mpa. The method will be extended to multilayer models in further studies.

Keywords: finite element method, fruits, inverse analysis, mechanical properties

Procedia PDF Downloads 337

Authors: Mohd. Khaidir Abu Talib, Noriyuki Yasufuku, Ryohei Ishikura

Abstract:

It is well recognized that peat can impede the proper hydration of cement because of high organic content, presence of humic acid and less solid particles. That means the large amount of cement is required in order to neutralize the acids or otherwise the process of the peat stabilization remains retarded. Nevertheless, adding a great quantity of cement into the peat is absolutely an unfriendly and uneconomical solution. Sugarcane production is world number one commodities and produced a lot of bagasse. Bagasse is burnt to generate power required for diverse activities in the factory and leave bagasse ash as a waste. Increasing concern of disposal of bagasse residual creates interest to explore the potential application of this material. The objective of this study is to develop alternative binders that are environment friendly and contribute towards sustainable management by utilizing sugarcane bagasse ash (SCBA) in the stabilization of peat soil. Alongside SCBA, Ordinary Portland Cement (OPC), calcium chloride (CaCl2) and silica sand (K7) were used as additives to stabilize the peat that sampled from Hokkaido, Japan. In obtaining the optimal mix design, specimens of stabilized peat were tested in unconfined compression. It was found that stabilized peat comprising 20% and 5% (PCB1-20 and PCB2-5) partial replacement of OPC with SCBA 1 and SCBA 2 attain the maximum unconfined compressive strength (UCS) and discovered greater than untreated soil (P) and UCS of peat-cement (PC) specimen. At the optimal mix design, the UCS of the stabilized peat specimens increased with increasing of curing time, preloading during curing, OPC dosage and K7 dosage. For PCB1-20 mixture, inclusion of a minimum OPC dosage of 300 kg/m3 and K7 dosage of 500 kg/m3 along with curing under 20kPa pressure is recommendable for the peat stabilization to be effective. However for PCB2-5 mixture, it suggested to use more OPC and K7 dosage or alternatively increase the preloading during curing to 40kPa in order to achieve minimum strength target. It can be concluded that SCBA 1 has better quality than SCBA 2 in peat stabilization especially the contribution made by its fine particle size.

Keywords: peat stabilization, sugarcane bagasse ash utilization, partial cement replacement, unconfined strength

Procedia PDF Downloads 519

Authors: Ranadhir Roy

Abstract:

Inverse problems arise in medical (molecular) imaging. These problems are characterized by large in three dimensions, and by the diffusion equation which models the physical phenomena within the media. The inverse problems are posed as a nonlinear optimization where the unknown parameters are found by minimizing the difference between the predicted data and the measured data. To obtain a unique and stable solution to an ill-posed inverse problem, a priori information must be used. Mathematical conditions to obtain stable solutions are established in Tikhonov’s regularization method, where the a priori information is introduced via a stabilizing functional, which may be designed to incorporate some relevant information of an inverse problem. Effective determination of the Tikhonov regularization parameter requires knowledge of the true solution, or in the case of optical imaging, the true image. Yet, in, clinically-based imaging, true image is not known. To alleviate these difficulties we have applied the penalty/modified barrier function (PMBF) method instead of Tikhonov regularization technique to make the inverse problems well-posed. Unlike the Tikhonov regularization method, the constrained optimization technique, which is based on simple bounds of the optical parameter properties of the tissue, can easily be implemented in the PMBF method. Imposing the constraints on the optical properties of the tissue explicitly restricts solution sets and can restore uniqueness. Like the Tikhonov regularization method, the PMBF method limits the size of the condition number of the Hessian matrix of the given objective function. The accuracy and the rapid convergence of the PMBF method require a good initial guess of the Lagrange multipliers. To obtain the initial guess of the multipliers, we use a least square unconstrained minimization problem. Three-dimensional images of fluorescence absorption coefficients and lifetimes were reconstructed from contact and noncontact experimentally measured data.

Keywords: constrained minimization, ill-conditioned inverse problems, Tikhonov regularization method, penalty modified barrier function method

Procedia PDF Downloads 257

Authors: Hanna Faron, Wojciech Marcinkowski, Daniel Prusak, Władysław Hamiga

Abstract:

Interest in composite materials comes out of two basic premises: their supreme mechanical and strength properties,combined with a small specific weight. Origin and evolution of modern composite materials bonds with development of manufacturing of synthetic fibers, which have begun during Second World War. Main condition to achieve intended properties of composite materials is proper bonding of reinforcing layer with appropriate adhesive in manufacturing process. It is one of the fundamental quality evaluation criterion of fabrication processes.

Keywords: SAE, formula student, composite materials, carbon fiber, Aramid fiber, hot wire cutter

Procedia PDF Downloads 496

Authors: Sarah Nasser, Anne Moreau, Alain Hedoux, Romain Jeantet, Guillaume Delaplace

Abstract:

Background: Spray dryed powders containing some caseins are commonly produced in dairy industry. It is widely admitted that the structure of casein evolves during powder storage, inducing a loss of solubility. However few studies evaluate accurately the destabilization mechanisms at molecular and mesoscopic level, in particular for Native Phospho Casein powder (NPC). Consequently, at the state of the art, it is very difficult to assess which secondary structure change or crosslinks initiate insolubility during storage. To address this issue, controlled ageing conditions have been applied to a NPC powder (which was obtained by spray drying a concentrate containing a higher content of casein (90%), whey protein (8%) and lactose (few %)). Evolution of structure and loss of solubility, with the effects of temperature and time of storage were systematically reported. Methods: FTIR spectroscopy, Raman and Circular Dichroism were used to monitor changes of secondary structure in dry powder and in solution after rehydration. Besides, proteomic tools and electrophoresis have been performed after varying storage conditions for evaluating aggregation and post translational modifications, like lactosylation or phosphorylation. Finally, Tof Sims and MEB were used to follow in parallel evolution of structure in surface and skin formation due to storage. Results + conclusion: These results highlight the important role of storage temperature in the stability of NPC. It is shown that this is not lactosylation at the heart of formation of aggregates, as advanced in others publications This is almost the rise of multitude post translational modifications (chemical cross link), added to disulphide bridges (physical cross link) wich contribute to the destabilisation of structure and aggregation of casein. A relative quantification of each kind of cross link, source of aggregates, is proposed. In addition, it has been proved that migration of lipids and formation of skin in surface during the ageing also explains the evolution of structure casein and thus the alterations of functional properties of NPC powder.

Keywords: casein, cross link, powder, storage

Procedia PDF Downloads 363

Authors: P. G. Siddheshwar, B. N. Veena

Abstract:

Rayleigh-B´enard convection of a nanoliquid in shallow, square and tall enclosures is studied using the Khanafer-Vafai-Lightstone single-phase model. The thermophysical properties of water, copper, copper-oxide, alumina, silver and titania at 3000 K under stagnant conditions that are collected from literature are used in calculating thermophysical properties of water-based nanoliquids. Phenomenological laws and mixture theory are used for calculating thermophysical properties. Free-free, rigid-rigid and rigid-free boundary conditions are considered in the study. Intractable Lorenz model for each boundary combination is derived and then reduced to the tractable Ginzburg-Landau model. The amplitude thus obtained is used to quantify the heat transport in terms of Nusselt number. Addition of nanoparticles is shown not to alter the influence of the nature of boundaries on the onset of convection as well as on heat transport. Amongst the three enclosures considered, it is found that tall and shallow enclosures transport maximum and minimum energy respectively. Enhancement of heat transport due to nanoparticles in the three enclosures is found to be in the range 3% - 11%. Comparison of results in the case of rigid-rigid boundaries is made with those of an earlier work and good agreement is found. The study has limitations in the sense that thermophysical properties are calculated by using various quantities modelled for static condition.

Keywords: enclosures, free-free, rigid-rigid, rigid-free boundaries, Ginzburg-Landau model, Lorenz model

Procedia PDF Downloads 227

Authors: Ratchadaporn Kaewmuang, Hussaya Maneesuwan, Thanyalak Chaisuwan, Sujitra Wongkasemjit

Abstract:

Mesoporous materials have been used in many applications, such as adsorbent and catalyst. SBA-15, a 2D hexagonal ordered mesoporous silica material, has not only high specific surface area, but also thicker wall, larger pore size, better hydrothermal stability, and mechanical properties than M41s. However, pure SBA-15 still lacks of redox properties. Therefore, bimetallic incorporation into framework is of interest since it can create new active sites. In this work, Ti-Fe-SBA-15 is studied and successfully synthesized via sol-gel process, using silatrane, FeCl3, and titanium (VI) isopropoxide as silica, iron, and titanium sources, respectively. The products are characterized by SAXD, FE-SEM, and N2 adsorption/desorption, DR-UV, and XRF.

Keywords: SBA-15, mesoporous silica, bimetallic, titanium, iron, silatrane

Procedia PDF Downloads 357

Authors: Farhan Lafta Rashid, Khudhair Abass Dawood, Ahmed Hashim

Abstract:

Recent advancements in nanotechnology have originated the new emerging heat transfer fluids called nanofluids. Nanofluids are prepared by dispersing and stably suspending nanometer sized solid particles in conventional heat transfer fluids. Past researches have shown that a very small amount of suspending nano-particles have the potential to enhance the thermo physical, transport, and radiative properties of the base fluid. At this research adding very small quantities of nano particle (TiO2) to pure water with different weights percent ranged 0.1, 0.2, 0.3, and 0.4 wt.%, we found that the best weight percent is 0.2 that gave more heat absorbed. Then adding glass impurities ranged 10, 20, and 30 wt. Percentage to the nano-fluid in order to enhance the absorbed heat so energy storage. The best glass weights percent is 0.3.

Keywords: energy storage, enhancement absorbed heat, glass impurities, solar energy

Procedia PDF Downloads 418

Authors: Hassan. A. Abas, Saad A. Aiban

Abstract:

Soil improvement by means of stone column method is used to improve sabkha soils in order to limit total and differential settlement and to achieve the required bearing capacity. Full-scale plate test was performed on site to confirm the achievement of required bearing capacity at the specified settlement. Despite the fact that this technique is widely used to improve sabkha soils, there are no studies focusing on the behavior of stone columns in such problematic soils. Sabkha soils are known for its high compressibility, low strength and water sensitivity due to loss of salt cementation upon flooding during installation of stone columns. Numerical modeling of plate load test assist to understand complicated behavior of sabkha – stone column interaction. This paper presents a three-dimensional Finite element model, using PLAXIS 3D software, to simulate vertical plate load tests on a stone column installed in sabkha. The predicted settlement values are in reasonable agreement with the field measure values and the field load - settlement curve can be predicted with good accuracy.

Keywords: soil improvement, stone column, sabkha, PLAXIS 3D

Procedia PDF Downloads 365

Authors: Anamarija Kuhar, Veronika Kloboves Prevodnik, Nataša Nolde, Ulrika Klopčič

Abstract:

The decision for immunocytochemistry (ICC) is usually made in the basis of the findings in Giemsa- and/or Papanicolaou- smears. More demanding diagnostic cases require preparation of additional cytological preparations. Therefore, it is convenient to suspend cytological samples in a liquid based medium (LBM) that preserve antigen and morphological properties. However, the duration of these properties being preserved in the medium is usually unknown. Eventually, cell morphology becomes impaired and altered, as well as antigen properties may be lost or become diffused. In this study, the influence of cytological sample storage length in in-house liquid based medium on antigen properties and cell morphology is evaluated. The question is how long the cytological samples in this medium can be stored so that the results of immunocytochemical reactions are still reliable and can be safely used in routine cytopathological diagnostics. The stability of 6 ICC markers that are most frequently used in everyday routine work were tested; Cytokeratin AE1/AE3, Calretinin, Epithelial specific antigen Ep-CAM (MOC-31), CD 45, Oestrogen receptor (ER), and Melanoma triple cocktail were tested on methanol fixed cytospins prepared from fresh fine needle aspiration biopsies, effusion samples, and disintegrated lymph nodes suspended in in-house cell medium. Cytospins were prepared on the day of the sampling as well as on the second, fourth, fifth, and eight day after sample collection. Next, they were fixed in methanol and immunocytochemically stained. Finally, the percentage of positive stained cells, reaction intensity, counterstaining, and cell morphology were assessed using two assessment methods: the internal assessment and the UK NEQAS ICC scheme assessment. Results show that the antigen properties for Cytokeratin AE1/AE3, MOC-31, CD 45, ER, and Melanoma triple cocktail were preserved even after 8 days of storage in in-house LBM, while the antigen properties for Calretinin remained unchanged only for 4 days. The key parameters for assessing detection of antigen are the proportion of cells with a positive reaction and intensity of staining. Well preserved cell morphology is highly important for reliable interpretation of ICC reaction. Therefore, it would be valuable to perform a similar analysis for other ICC markers to determine the duration in which the antigen and morphological properties are preserved in LBM.

Keywords: cytology samples, cytospins, immunocytochemistry, liquid-based cytology

Procedia PDF Downloads 125

Authors: Nesrine Frifita, Mohamed Gharbi, Kevin Mickus

Abstract:

Physical methods based on gravity, seismic and seismological data were adopted to clarify the relationship between the distribution of seismicity and the crustal deformations under the chott belts and surrounding regions, in southern atlas of Tunisia. Gafsa and its surrounding were described as a moderate seismic zone, and the fault of Gafsa is one of most seismically active faults in Tunisia in general, and in the southern Atlas in particularly. The present work aims to prove a logical relationship between the distribution of seismicity and deformations which strongly related to thickness and density variations within the basement and sedimentary cover along the study area, through several physical methods; gravity, seismic and seismological data were interpreted to calculate physical propriety of the subsurface rocks, the depth and geometry of active faults and causatives bodies. Findings show that depths variation and mixed thin and thick skinned structural style characterizing the chott belts explain the moderate seismicity in the study area.

Keywords: potential fields, seismicity, Southern Atlas, Tunisia

Procedia PDF Downloads 97

Authors: Ankur Sachan

Abstract:

Carbon dioxide being the most anthropogenic greenhouse gas,it needs to be isolated from entering into atmosphere. Carbon capture and storage is process that captures CO2 emitted from various sources, separates it from other gases and stores it in a safe place preferably in underground geological formations for large period of time. It is then purified and monitored so that can be made to reuse. Monoethanolamine, zeolitic imidazolate framework, microalgae, membranes etc are utilized to capture CO2. Post-combustion, pre-combustion and oxyfuel combustion along with chemical looping combustion are technologies for scrubbing CO2. The properties of CO2 being easily miscible and readily dissolving in oil with impurities makes it capable for numerous applications such as in producing oil by enhanced oil recovery (EOR), Bio CCS Algal Synthesis etc. CO2-EOR operation is capable to produce million barrels of oil and extend the field's lifetime as in case of Weyburn Oil Field in Canada. The physical storage of CO2 is technically the most feasible direction provided that the associated safety and sustainability issues can be met and new materials for CCUS process at low cost are urgently found so that so that fossil based systems with carbon capture are cost competitive.

Keywords: carbon capture, CCUS, sustainability, oil

Procedia PDF Downloads 500

Authors: A. Khalina, K. Shaharuddin, M. S. Wahab, M. P. Saiman, H. A. Aisyah

Abstract:

This paper investigates the effect of alkali treatment and mechanical properties of kenaf (Hibiscus cannabinus) fibre for the development of yarn. Two different fibre sources are used for the yarn production. Kenaf fibres were treated with sodium hydroxide (NaOH) in the concentration of 3, 6, 9, and 12% prior to fibre opening process and tested for their tensile strength and Young’s modulus. Then, the selected fibres were introduced to fibre opener at three different opening processing parameters; namely, speed of roller feeder, small drum, and big drum. The diameter size, surface morphology, and fibre durability towards machine of the fibres were characterized. The results show that concentrations of NaOH used have greater effects on fibre mechanical properties. From this study, the tensile and modulus properties of the treated fibres for both types have improved significantly as compared to untreated fibres, especially at the optimum level of 6% NaOH. It is also interesting to highlight that 6% NaOH is the optimum concentration for the alkaline treatment. The untreated and treated fibres at 6% NaOH were then introduced to fibre opener, and it was found that the treated fibre produced higher fibre diameter with better surface morphology compared to the untreated fibre. Higher speed parameter during opening was found to produce higher yield of opened-kenaf fibres.

Keywords: alkaline treatment, kenaf fibre, tensile strength, yarn production

Procedia PDF Downloads 231

Authors: Bello Theodora O., Animola Odunayo V., Owoade Johnson T.

Abstract:

With the advent of Covid-19, online classroom instruction became a very important mode of instruction delivery during which learners were engaged in both collaborative and online interactive learning process, but along with it are challenges as well as its deliverables. This study therefore investigated the various online platform used by the students for learning among fresh undergraduate students of Obafemi Awolowo University, Ile-Ife, Osun Sate. It also assessed the student’s perception towards online learning in the university and examined the influence of collaborative learning among the students. Lastly, it examined the problems that are associated with collaborative online learning instruction in the university. These were with a view to providing empirical information on problems and prospects of online classroom instruction among fresh undergraduate physical science students of Obafemi Awolowo University, Ile-Ife. The study employed a descriptive survey research technique. The population comprised all the fresh undergraduates in physical science departments of Obafemi Awolowo University, Ile-Ife. The sample consisted two hundred freshmen in physical science departments of Obafemi Awolowo University, Ile-Ife, who were selected using simple random techniques. During the selection, a questionnaire was used to collect data from the respondents. The data were analyzed using appropriate descriptive of frequency, simple percentage, and mean. Results showed that Google Meet 149(74.5%), Telegram 120(60.0%), and Google Classroom 143(71.5%), are the prominent online classroom instruction used by the students in Obafemi Awolowo University, Ile-Ife. The results also showed that the freshmen’s perception towards online classroom instruction in Obafemi Awolowo University, Ile-Ife is low with cluster mean of 2.97. It further revealed that collaborative learning enhances the learning ability of below average learners more than that of the above average and average students (73.6%). Finally, the result showed that they are affirmative of the problems associated with online classroom instruction in Obafemi Awolowo University, Ile-Ife with cluster mean of 3.01. The result concluded that most Online platform used by the fresher’s students in Obafemi Awolowo University, Ile-Ife are Google Meet, Telegram and Google Classroom. The students have negatives perception towards online classroom instruction and the students are affirmative of the problems associated with online classroom instruction among physical science freshmen in Obafemi Awolowo University, Ile-Ife.

Keywords: online, instruction, freshmen, physical science, collaborative

Procedia PDF Downloads 40

Authors: E. I. Ugwu

Abstract:

Theoretical analysis of the optical and Solid State properties of ZnS thin film using beam propagation technique in which a scalar wave is propagated through the material thin film deposited on a substrate with the assumption that the dielectric medium is section into a homogenous reference dielectric constant term, and a perturbed dielectric term, representing the deposited thin film medium is presented in this work. These two terms, constitute arbitrary complex dielectric function that describes dielectric perturbation imposed by the medium of for the system. This is substituted into a defined scalar wave equation in which the appropriate Green’s Function was defined on it and solved using series technique. The green’s value obtained from Green’s Function was used in Dyson’s and Lippmann Schwinger equations in conjunction with Born approximation method in computing the propagated field for different input regions of field wavelength during which the influence of the dielectric constants and mesh size of the thin film on the propagating field were depicted. The results obtained from the computed field were used in turn to generate the data that were used to compute the band gaps, solid state and optical properties of the thin film such as reflectance, Transmittance and reflectance with which the band gap obtained was found to be in close approximate to that of experimental value.

Keywords: scalar wave, optical and solid state properties, thin film, dielectric medium, perturbation, Lippmann Schwinger equations, Green’s Function, propagation

Procedia PDF Downloads 421

Authors: Chung-Yang Chuang, Hui-Min Wang, Min-Yan Dong, Chang-Jung Chang

Abstract:

PET fiber is the most widely used fiber worldwide. This man-made fiber is prepared from petroleum chemicals, which may cause environmental pollution and resource exhausting issues, such as the use of non-renewable sources, greenhouse gas emission and discharge of wastewater. Therefore, the textile made by recycle-PET is the trend in the future. Recycle-PET fiber, compared with petroleum-made PET, shows lower carbon emissions and resource exhaustion. However, “fabric decoloring” is the key barrier to textile recycling. The dyes existing in the fabrics may cause PET chain degradation and appearance drawbacks during the textile recycling process. In this research, the water-based decoloring agent was used to remove the dispersed dye in the PET fabrics in order to obtain the colorless PET fabrics after the decoloring process. The decoloring rate of PET fabrics after the decoloring process was up to 99.0%. This research provides a better solution to resolve the issues of appearance and physical properties degradation of fabrics-recycle PET materials due to the residual dye. It may be possible to convert waste PET textiles into new high-quality PET fiber and build up the loop of PET textile recycling.

Keywords: PET, decoloring, disperse dye, textile recycle

Procedia PDF Downloads 118

Authors: Inayat Shah, Muhammad Omar Malik, Ghareeb Alshuwaier, Ronald H. Baxendale

Abstract:

Background: The balance between angiogenesis and angiostasis is important in growth and developmental processes in the body. Angiogenic and angiostatic mediators control this balance. Endostatin is one of the prominent angiostatic mediators. The marked angiostatic effect of endostatin includes inhibiting endothelial cell migration, proliferation and apoptosis. Physical activity decreases the risk and development of many angiogenesis related health problems including atherosclerosis and numerous cancers. Physiological influences of different physical activities on plasma endostatin concentration are controversial and not completely clear. Moreover, correlation of physical characteristics and metabolic predictors during physical activity on circulating endostatin is indistinct and poorly speculated. The study aimed to determine the effects of mild, moderate and vigorous exercise on the concentration of endostatin in plasma. Methodology: 22 participants, 16 males (age = 30.6 ± 7.8 years) and 6 females (age = 26.5 ± 5 years) were recruited. Weekly session of different intensities exercise based on the predicted maximum heart of the participants [60%(low), 70% (moderate) and 80% (vigorous)] were carried out. The duration and work rate for each participant was determined through sub-maximal exercise. Standardization of the session was done on total energy expenditure of the participants per session. One pre exercise and two post exercise samples were taken at intervals of 10 and 60 minutes. Results: Pre-exercise mean endostatin was 101 ± 20 ng/dl. Low intensity exercise insignificantly decreased the endostatin concentration in plasma at 10 and 60 minutes 97 ± 20 ng/dl (p= 0.5), 98 ± 23 ng/dl (p= 0.8)). However, moderate (p= 0.022, 0.004) and vigorous intensities (p ≤ 0.001, 0.02) increased the endostatin concentrations significantly at both 10 and 60 minutes intervals respectively. The effects were not significantly influenced by gender, exercise mode (walking vs. running), components of exercise (HR, Speed, Gradients, distance, duration) or metabolism during exercise (VO₂ max, VCO₂, RER, energy expenditure, rate of carbohydrate or fats oxidation). Conclusion: Low intensity exercises did not influence endostatin concentration. However, moderate to high intensity exercises significantly increase endostatin concentration and may have potential benefits.

Keywords: angiogenesis, exercise, endostatin, physical activity

Procedia PDF Downloads 211

Authors: Delele Worku Ayele, Bing-Joe Hwang

Abstract:

A method that does not employ hot injection techniques has been developed for the size-tunable synthesis of high-quality CdSe quantum dots (QDs) with a zinc blende structure. In this environmentally benign synthetic route, which uses relatively less toxic precursors, solvents, and capping ligands, CdSe QDs that absorb visible light are obtained. The size of the as-prepared CdSe QDs and, thus, their optical properties can be manipulated by changing the microwave reaction conditions. The QDs are characterized by XRD, TEM, UV-vis, FTIR, time-resolved fluorescence spectroscopy, and fluorescence spectrophotometry. In this approach, the reaction is conducted in open air and at a much lower temperature than in hot injection techniques. The use of microwaves in this process allows for a highly reproducible and effective synthesis protocol that is fully adaptable for mass production and can be easily employed to synthesize a variety of semiconductor QDs with the desired properties. The possible application of the as-prepared CdSe QDs has been also assessed using deposition on TiO2 films.

Keywords: CdSe QDs, Na2SeSO3, microwave (MW), oleic acid, mass production, average life time

Procedia PDF Downloads 691

Authors: Ahmet Koyuncu, Abdullah Berkan Erdogmus, Orkun Dogu, Sinan Uygur

Abstract:

Thermoelectric modules are integrated to electronic components to keep their temperature in specific values in electronic cooling applications. They can be used in different ambient temperatures. The cold side temperatures of thermoelectric modules depend on their hot side temperatures, operation currents, and heat loads. Performance curves of thermoelectric modules are given at most two different hot surface temperatures in product catalogs. Characteristic properties are required to select appropriate thermoelectric modules in thermal design phase of projects. Generally, manufacturers do not provide characteristic material property values of thermoelectric modules to customers for confidentiality. Common commercial software applied like ANSYS ICEPAK, FloEFD, etc., include thermoelectric modules in their libraries. Therefore, they can be easily used to predict the effect of thermoelectric usage in thermal design. Some software requires only the performance values in different temperatures. However, others like ICEPAK require three temperature-dependent equations for material properties (Seebeck coefficient (α), electrical resistivity (β), and thermal conductivity (γ)). Since the number and the variety of thermoelectric modules are limited in this software, definitions of characteristic material properties of thermoelectric modules could be required. In this manuscript, the method of derivation of characteristic material properties from the datasheet of thermoelectric modules is presented. Material characteristics were estimated from two different performance curves by experimentally and numerically in this study. Numerical calculations are accomplished in ICEPAK by using a thermoelectric module exists in the ICEPAK library. A new experimental setup was established to perform experimental study. Because of similar results of numerical and experimental studies, it can be said that proposed equations are approved. This approximation can be suggested for the analysis includes different type or brand of TEC modules.

Keywords: electrical resistivity, material characteristics, thermal conductivity, thermoelectric coolers, seebeck coefficient

Procedia PDF Downloads 161

Authors: K. Jankowski, M. Pawlikowski, A. Makuch, K. Skalski

Abstract:

Depth-sensing indentation (DSI) or nanoindentation is becoming a more and more popular method of measuring mechanical properties of various materials and tissues at a micro-scale. This technique allows measurements without complicated sample preparation procedures which makes this method very useful. As a result of measurement force and displacement of the intender are obtained. It is also possible to determine three measures of hardness i.e. Martens hardness (HM), nanohardness (HIT), Vickers hardness (HV) and Young modulus EIT. In this work trabecular bone mechanical properties were investigated. The bone samples were harvested from human femoral heads during hip replacement surgery. Patients were of different age, sexes and stages of tissue degeneration caused by osteoarthritis. The specimens were divided into three groups. Each group contained samples harvested from patients of different range of age. All samples were investigated with the same measurement conditions. The maximum load was Pmax=500 mN and the loading rate was 500 mN/min. The tests were held without hold at the peak force. The tests were conducted with indenter Vickers tip and spherical tip of the diameter 0.2 mm. Each trabecular bone sample was tested 7 times in a close area of the same trabecula. The measured loading P as a function of indentation depth allowed to obtain hysteresis loop and HM, HIT, HV, EIT. Results for arbitrarily chosen sample are HM=289.95 ± 42.31 MPa, HIT=430.75 ± 45.37 MPa, HV=40.66 ± 4.28 Vickers, EIT=7.37 ± 1.84 GPa for Vickers tip and HM=115.19 ± 15.03 MPa, HIT=165.80 ± 19.30 MPa, HV=16.90 ± 1.97 Vickers, EIT=5.30 ± 1.31 GPa for spherical tip. Results of nanoindentation tests show that this method is very useful and is perfect for obtaining mechanical properties of trabecular bone. Estimated values of elastic modulus are similar. The differences between hardness are significant but it is a result of using two different types of tips. However, it has to be emphasised that the differences in the values of elastic modulus and hardness result from different testing protocols, anisotropy and asymmetry of the micro-samples and the hydration of bone.

Keywords: human bone, mechanical properties, nano hardness nanoindentation, trabecular bone

Procedia PDF Downloads 261

Authors: W. F. Ribeiro, J. L. N. Góes

Abstract:

The industrial process adds to engineering wood products features absent in solid wood, with homogeneous structure and reduced defects, improved physical and mechanical properties, bio-deterioration, resistance and better dimensional stability, improving quality and increasing the reliability of structures wood. These features combined with using fast-growing trees, make them environmentally ecological products, ensuring a strong consumer market. The wood I-joists are manufactured by the industrial profiles bonding flange and web, an important aspect of the production of wooden I-beams is the adhesive joint that bonds the web to the flange. Adhesives can effectively transfer and distribute stresses, thereby increasing the strength and stiffness of the composite. The objective of this study is to evaluate different resins in a shear strain specimens with the aim of analyzing the most efficient resin and possibility of using national products, reducing the manufacturing cost. First was conducted a literature review, where established the geometry and materials generally used, then established and analyzed 8 national resins and produced six specimens for each.

Keywords: engineered wood products, structural resin, wood i-joist, Pinus taeda

Procedia PDF Downloads 259

Authors: Rehan Waheed, Abdul Shakoor

Abstract:

Distortion produced during welding of thin metal plates is a problem in many industries. The purpose of this research was to study distortion produced during welding in 2mm Mild Steel plate by simulating the welding process using Finite Element Analysis. Simulation of welding process requires a couple field transient analyses. At first a transient thermal analysis is performed and the temperature obtained from thermal analysis is used as input in structural analysis to find distortion. An actual weld sample is prepared and the weld distortion produced is measured. The simulated and actual results were in quite agreement with each other and it has been found that there is profound deflection at center of plate. Temperature dependent material properties play significant role in prediction of weld distortion. The results of this research can be used for prediction and control of weld distortion in large steel structures by changing different weld parameters.

Keywords: welding simulation, FEA, welding distortion, temperature dependent mechanical properties

Procedia PDF Downloads 372

Authors: K. S. Poutanen, P. Dussort, A. Erkner, S. Fiszman, K. Karnik, M. Kristensen, C. F. M. Marsaux, S. Miquel-Kergoat, S. Pentikäinen, P. Putz, R. E. Steinert, J. Slavin, D. J. Mela

Abstract:

Dietary fiber (DF) intake has been associated with lower body weight or less weight gain. These effects are generally attributed to putative effects of DF on appetite. Many intervention studies have tested the effect of DFs on appetite-related measures, with inconsistent results. However, DF includes a wide category of different compounds with diverse chemical and physical characteristics, and correspondingly diverse effects in human digestion. Thus, inconsistent results between DF consumption and appetite are not surprising. The specific contribution of different compounds with varying physico-chemical properties to appetite control and the mediating mechanisms are not well characterized. This systematic review aimed to assess the influence of specific DF characteristics, including viscosity, gel forming capacity, fermentability, and molecular weight, on appetite-related outcomes in healthy humans. Medline and FSTA databases were searched for controlled human intervention trials, testing the effects of well-characterized DFs on subjective satiety/appetite or energy intake outcomes. Studies were included only if they reported: 1) fiber name and origin, and 2) data on viscosity, gelling properties, fermentability, or molecular weight of the DF materials tested. The search generated 3001 unique records, 322 of which were selected for further consideration from title and abstract screening. Of these, 149 were excluded due to insufficient fiber characterization and 124 for other reasons (not original article, not randomized controlled trial, or no appetite related outcome), leaving 49 papers meeting all the inclusion criteria, most of which reported results from acute testing (<1 day). The eligible 49 papers described 90 comparisons of DFs in foods, beverages or supplements. DF-containing material of interest was efficacious for at least one appetite-related outcome in 51/90 comparisons. Gel-forming DF sources were most consistently efficacious but there were no clear associations between viscosity, MW or fermentability and appetite-related outcomes. A considerable number of papers had to be excluded from the review due to shortcomings in fiber characterization. To build understanding about the impact of DF on satiety/appetite specifically there should be clear hypotheses about the mechanisms behind the proposed beneficial effect of DF material on appetite, and sufficient data about the DF properties relevant for the hypothesized mechanisms to justify clinical testing. The hypothesized mechanisms should also guide the decision about relevant duration of exposure in studies, i.e. are the effects expected to occur during acute time frame (related to stomach emptying, digestion rate, etc.) or develop from sustained exposure (gut fermentation mediated mechanisms). More consistent measurement methods and reporting of fiber specifications and characterization are needed to establish reliable structure-function relationships for DF and health outcomes.

Keywords: appetite, dietary fiber, physico-chemical properties, satiety

Procedia PDF Downloads 218

Authors: A.I. Adeyemo

Abstract:

Ikogosi warm spring results from a complex mechanical and chemical forces that generates internal heat in the rocks forming a warm and cold water at the same geographical location at the same time. From time immemorial, the local community had thought, it to be the work of a deity, and they were worshipping the spring. This complex phenomenon has been a source of tourist attraction to both local and international tourists over the years. 450 copies of a structured questionnaire were given out, and a total of 500 respondents were interviewed. The result showed that ikogosi warm spring impacts the community positively by providing employment to the teeming youths, and it provides income to traders. The result shows that 66% of the respondents confirmed that it increased their income and that transportation business increased more than 73%.the level of enlightenment and socialization increased greatly in the community. However, it also impacted the community negatively as it increased crime rates such as stealing, kidnapping, prostitution, and unwanted pregnancy among the secondary school girls and the other teenagers. Generally, 50% of the respondents reported that tourism in the warm spring results in insecurity in the community. IT also increased environmental problems such as noise and waste pollutions; the continuous movement on the land results in soil compartment leading to erosion, and leaching, which also results in loss of soil fertility. It was concluded that if the potentials of the spring are fully tapped, it will be a good avenue for income generation to the country.

Keywords: community, Ikogosi, revenue, warm spring

Procedia PDF Downloads 139