Search results for: current density distribution

Authors: A. A. Purohit, A. Basu, K. A. Chavan, M. D. Kudale

Abstract:

Many estuarine harbours in the world are facing the problem of siltation in docks, channel entrances, etc. The harbours in India are not an exception and require maintenance dredging to achieve navigable depths for keeping them operable. Hence, dredging is inevitable and is a costly affair. The heavy siltation in docks in well mixed tide dominated estuaries is mainly due to settlement of cohesive sediments in suspension. As such there is a need to have a permanent solution for minimising the siltation in such docks to alter the hydrodynamic flow field responsible for siltation by constructing structures outside the dock. One of such docks on the west coast of India, wherein siltation of about 2.5-3 m/annum prevails, was considered to understand the hydrodynamic flow field responsible for siltation. The dock is situated in such a region where macro type of semi-diurnal tide (range of about 5m) prevails. In order to change the flow field responsible for siltation inside the dock, suitability of Current Deflecting Wall (CDW) outside the dock was studied, which will minimise the sediment exchange rate and siltation in the dock. The well calibrated physical tidal model was used to understand the flow field during various phases of tide for the existing dock in Mumbai harbour. At the harbour entrance where the tidal flux exchanges in/out of the dock, measurements on water level and current were made to estimate the sediment transport capacity. The distorted scaled model (1:400 (H) & 1:80 (V)) of Mumbai area was used to study the tidal flow phenomenon, wherein tides are generated by automatic tide generator. Hydraulic model studies carried out under the existing condition (without CDW) reveal that, during initial hours of flood tide, flow hugs the docks breakwater and part of flow which enters the dock forms number of eddies of varying sizes inside the basin, while remaining part of flow bypasses the entrance of dock. During ebb, flow direction reverses, and part of the flow re-enters the dock from outside and creates eddies at its entrance. These eddies do not allow water/sediment-mass to come out and result in settlement of sediments in dock both due to eddies and more retention of sediment. At latter hours, current strength outside the dock entrance reduces and allows the water-mass of dock to come out. In order to improve flow field inside the dockyard, two CDWs of length 300 m and 40 m were proposed outside the dock breakwater and inline to Pier-wall at dock entrance. Model studies reveal that, during flood, major flow gets deflected away from the entrance and no eddies are formed inside the dock, while during ebb flow does not re-enter the dock, and sediment flux immediately starts emptying it during initial hours of ebb. This reduces not only the entry of sediment in dock by about 40% but also the deposition by about 42% due to less retention. Thus, CDW is a promising solution to significantly reduce siltation in dock.

Keywords: current deflecting wall, eddies, hydraulic model, macro tide, siltation

Procedia PDF Downloads 299

Authors: Mehdi Shekarbeigi

Abstract:

The consolidation of loose substrates as well as substrate layers through promoting stabilizing materials is one of the most commonly used road construction techniques. Cement, lime, and flax, as well as asphalt emulsion, are common materials used for soil stabilization to enhance the soil’s strength and durability properties. Cement could be simply used to stabilize permeable materials such as sand in a relatively short time threshold. In this research, typical Portland cement is selected for the stabilization of isotropic sand; the effect of static and cyclic loading on the behavior of these soils has been examined with various percentages of Portland cement. Thus, firstly, a soil’s general features are investigated, and then static tests, including direct cutting, density and single axis tests, and California Bearing Ratio, are performed on the samples. After that, the dynamic behavior of cement on silica sand with the same grain size is analyzed. These experiments are conducted on cement samples of 3, 6, and 9 of the same rates and ineffective limiting pressures of 0 to 1200 kPa with 200 kPa steps of the face according to American Society for Testing and Materials D 3999 standards. Also, to test the effect of temperature on molds and frost samples, 0, 5, 10, and 20 are carried out during 0, 5, 10, and 20-second periods. Results of the static tests showed that increasing the cement percentage increases the soil density and shear strength. The single-axis compressive strength increase is higher for samples with higher cement content and lower densities. The results also illustrate the relationship between single-axial compressive strength and cement weight parameters. Results of the dynamic experiments indicate that increasing the number of loading cycles and melting and freezing cycles enhances permeability and decreases the applied pressure. According to the results of this research, it could be stated that samples containing 9% cement have the highest amount of shear modulus and, therefore, decrease the permeability of soil. This amount could be considered as the optimal amount. Also, the enhancement of effective limited pressure from 400 to 800kPa increased the shear modulus of the sample by an average of 20 to 30 percent in small strains.

Keywords: cement, isotropic sands, static load, three-axis cycle, melting and freezing cycles

Procedia PDF Downloads 82

Authors: Hwayeon Song

Abstract:

The long-term purpose of research and development (R&D) programs is to strengthen national competitiveness by developing new knowledge and technologies. Thus, it is important to determine a proper budget for government programs to maintain the vigor of R&D when the total funding is tight due to the national deficit. In this regard, a ripple effect analysis for the budgetary changes in R&D programs is necessary as well as an investigation of the current status. This study proposes a new approach using Artificial Neural Networks (ANN) for both tasks. It particularly focuses on R&D programs related to Construction and Transportation (C&T) technology in Korea. First, key factors in C&T technology are explored to draw impact indicators in three areas: economy, society, and science and technology (S&T). Simultaneously, ANN is employed to evaluate the relationship between data variables. From this process, four major components in R&D including research personnel, expenses, management, and equipment are assessed. Then the ripple effect analysis is performed to see the changes in the hypothetical future by modifying current data. Any research findings can offer an alternative strategy about R&D programs as well as a new analysis tool.

Keywords: Artificial Neural Networks, construction and transportation technology, Government Research and Development, Ripple Effect

Procedia PDF Downloads 251

Authors: Lingxiao Yang, Xin Wang, Bo Xu, Zhenqian Chen

Abstract:

Due to its outstanding environmental performance, higher heating temperature and excellent low-temperature performance, transcritical carbon dioxide (CO₂) heat pumps are receiving more and more attention. However, improperly set operating parameters have a serious negative impact on the performance of the transcritical CO₂ heat pump due to the properties of CO₂. In this study, the heat transfer characteristics of the gas cooler are studied based on the modified “three-stage” gas cooler, then the effect of three operating parameters, compressor speed, gas cooler water-inlet flowrate and gas cooler water-inlet temperature, on the heating process of the system are investigated from the perspective of thermal quality and heat capacity. The results shows that: In the heat transfer process of gas cooler, the temperature distribution of CO₂ and water shows a typical “two region” and “three zone” pattern; The rise in the cooling pressure of CO₂ serves to increase the thermal quality on the CO₂ side of the gas cooler, which in turn improves the heating temperature of the system; Nevertheless, the elevated thermal quality on the CO₂ side can exacerbate the mismatch of heat capacity on both sides of the gas cooler, thereby adversely affecting the system coefficient of performance (COP); Furthermore, increasing compressor speed mitigates the mismatch in heat capacity caused by elevated thermal quality, which is exacerbated by decreasing gas cooler water-inlet flowrate and rising gas cooler water-inlet temperature; As a delegate, the varying compressor speed results in a 7.1°C increase in heating temperature within the experimental range, accompanied by a 10.01% decrease in COP and an 11.36% increase in heating capacity. This study can not only provide an important reference for the theoretical analysis and control strategy of the transcritical CO₂ heat pump, but also guide the related simulation and the design of the gas cooler. However, the range of experimental parameters in the current study is small and the conclusions drawn are not further analysed quantitatively. Therefore, expanding the range of parameters studied and proposing corresponding quantitative conclusions and indicators with universal applicability could greatly increase the practical applicability of this study. This is also the goal of our next research.

Keywords: transcritical CO₂ heat pump, gas cooler, heat capacity, thermal quality

Procedia PDF Downloads 31

Authors: Monika Moggert

Abstract:

The aim of the research evaluates the local centers' development of Berlin, the capital of Germany. There are included studies of their potential, considers the possibility of applying different cultural influences and the issue of the current demographic transformation of Europe. The solution utilizes the analysis of historical, cultural, political and sociological changes after 2nd World War; the exploration of historical as well as strategic maps and personal evaluation of the current condition of selected boroughs – Berlin Neuköln, Kreuzberg and Wedding, where more than 30% of the inhabitants have a migration background. The research provides an example of the likely development of centers in urban agglomerations. It examines the issue of local centers with an inhumane scale in contrast to small-scale centering sites, mostly located in areas largely with immigrant communities. The research results enable a better understanding of the influence of different cultures and lifestyles on the appearance of the city and its local centers. We can use it as an inspiration for the new design of the Berlin centers. The results will be used for further research on urban space development in the cultural environment of Europe and the Middle East as well.

Keywords: Berlin, cultural environment, life in the city, public and urban space, the urban city centers development, town and society

Procedia PDF Downloads 201

Authors: Pavel Prochazka

Abstract:

The study deals with transducers for measuring vibration displacements of rotating blade tips in turbomachines. In order to prevent major accidents with extensive economic consequences, it shows an urgent need for every low-pressure steam turbine stage being equipped with modern non-contact measuring system providing information on blade loading, damage and residual lifetime under operation. The requirement of measuring vibration and static characteristics of steam turbine blades, therefore, calls for the development and operational verification of both new types of sensors and measuring principles and methods. The task is really demanding: to measure displacements of blade tips with a resolution of the order of 10 μm by speeds up to 750 m/s, humidity 100% and temperatures up to 200 °C. While in gas turbines are used primarily capacitive and optical transducers, these transducers cannot be used in steam turbines. The reason is moisture vapor, droplets of condensing water and dirt, which disable the function of sensors. Therefore, the most feasible approach was to focus on research of electromagnetic sensors featuring promising characteristics for given blade materials in a steam environment. Following types of sensors have been developed and both experimentally and theoretically studied in the Institute of Thermodynamics, Academy of Sciences of the Czech Republic: eddy-current, Hall effect, inductive and magnetoresistive. Eddy-current transducers demand a small distance of 1 to 2 mm and change properties in the harsh environment of steam turbines. Hall effect sensors have relatively low sensitivity, high values of offset, drift, and especially noise. Induction sensors do not require any supply current and have a simple construction. The magnitude of the sensors output voltage is dependent on the velocity of the measured body and concurrently on the varying magnetic induction, and they cannot be used statically. Magnetoresistive sensors are formed by magnetoresistors arranged into a Wheatstone bridge. Supplying the sensor from a current source provides better linearity. The MR sensors can be used permanently for temperatures up to 200 °C at lower values of the supply current of about 1 mA. The frequency range of 0 to 300 kHz is by an order higher comparing to the Hall effect and induction sensors. The frequency band starts at zero frequency, which is very important because the sensors can be calibrated statically. The MR sensors feature high sensitivity and low noise. The symmetry of the bridge arrangement leads to a high common mode rejection ratio and suppressing disturbances, which is important, especially in industrial applications. The MR sensors feature high sensitivity, high common mode rejection ratio, and low noise, which is important, especially in industrial applications. Magnetoresistive transducers provide a range of excellent properties indicating their priority for displacement measurements of rotating blades in turbomachines.

Keywords: turbines, blade vibration, blade tip timing, non-contact sensors, magnetoresistive sensors

Procedia PDF Downloads 132

Authors: Hanizam Awang, Muhammad Hafiz Ahmad

Abstract:

An experimental study was conducted on foamed concrete with synthetic and natural fibres consisting of AR-glass, polypropylene, steel, kenaf and oil palm fibre. The foamed concrete mixtures produced had a target density of 1000 kg/m3 and a mix ratio of (1:1.5:0.45). The fibres were used as additives. The inclusion of fibre was maintained at a volumetric fraction of 0.25 and 0.4 %. The water absorption, thermal and shrinkage were determined to study the effect of the fibre on the durability properties of foamed concrete. The results showed that AR-glass fibre has the lowest percentage value of drying shrinkage compared to others.

Keywords: foamed concrete, fibres, durability, construction, geological engineering

Procedia PDF Downloads 454

Authors: Natia Jalagonia, Jimsher Maisuradze, Karlo Barbakadze, Tinatin Kuchukhidze

Abstract:

At present intensive scientific researches of ceramics, cermets and metal alloys have been conducted for improving materials physical-mechanical characteristics. In purpose of increasing impact strength of ceramics based on alumina, simple method of graphene homogenization was developed. Homogeneous distribution of graphene (homogenization) in pressing composite became possible through the connection of functional groups of graphene oxide (-OH, -COOH, -O-O- and others) and alumina superficial OH groups with aluminum organic compounds. These two components connect with each other with -O-Al–O- bonds, and by their thermal treatment (300–500°C), graphene and alumina phase are transformed. Thus, choosing of aluminum organic compounds for modification is stipulated by the following opinion: aluminum organic compounds fragments fixed on graphene and alumina finally are transformed into an integral part of the matrix. By using of other elements as modifier on the matrix surface (Al2O3) other phases are transformed, which change sharply physical-mechanical properties of ceramic composites, for this reason, effect caused by the inclusion of graphene will be unknown. Fixing graphene fragments on alumina surface by alumoorganic compounds result in new type graphene-alumina complex, in which these two components are connected by C-O-Al bonds. Part of carbon atoms in graphene oxide are in sp3 hybrid state, so functional groups (-OH, -COOH) are located on both sides of graphene oxide layer. Aluminum organic compound reacts with graphene oxide at the room temperature, and modified graphene oxide is obtained: R2Al-O-[graphene]–COOAlR2. Remaining Al–C bonds also reacts rapidly with surface OH groups of alumina. In a result of these process, pressing powdery composite [Al2O3]-O-Al-O-[graphene]–COO–Al–O–[Al2O3] is obtained. For the purpose, graphene oxide suspension in dry toluene have added alumoorganic compound Al(iC4H9)3 in toluene with equimolecular ratio. Obtained suspension has put in the flask and removed solution in a rotary evaporate presence nitrogen atmosphere. Obtained powdery have been researched and used to consolidation of ceramic materials based on alumina. Ceramic composites are obtained in high temperature vacuum furnace with different temperature and pressure conditions. Received ceramics do not have open pores and their density reaches 99.5 % of TD. During the work, the following devices have been used: High temperature vacuum furnace OXY-GON Industries Inc (USA), device of spark-plasma synthesis, induction furnace, Electronic Scanning Microscopes Nikon Eclipse LV 150, Optical Microscope NMM-800TRF, Planetary mill Pulverisette 7 premium line, Shimadzu Dynamic Ultra Micro Hardness Tester DUH-211S, Analysette 12 Dynasizer and others.

Keywords: graphene oxide, alumo-organic, ceramic

Procedia PDF Downloads 310

Authors: Mustafa Eruyar, Ersoy Pehlivan, Fatih Kafalı, Fatih Gundogan

Abstract:

All megacities are not only under the pressure of common urbanization and growth problems but also dealing with different challenges according to their specific circumstances. However, the majority of cities focuses mainly on popular smart city projects, which are usually driven by strong private sector, regardless of their characteristics, each city needs to develop customized projects within a tailor-made smart city roadmap to be able to solve its own challenges. Smart city manifest, helps citizens to feel the action better than good reading smart city vision statements, which consists of five elements; namely purpose, values, mission, vision, and strategy. This study designs a methodology for smart city roadmap based on a top-down approach, breaking down of smart city manifest to feasible projects for a systematic smart city transformation. This methodology was implemented in Istanbul smart city transformation program which includes smart city literature review, current state analysis, roadmap, and architecture projects, respectively. Istanbul smart city roadmap project followed an extensive literature review of certain leading smart cities around the world and benchmarking of the city’s current state using well known smart city indices. In the project, needs of citizens and service providers of the city were identified via stakeholder, persona and social media analysis. The project aimed to develop smart city projects targeting fulfilling related needs by implementing a gap analysis between current state and foreseen plans. As a result, in 11 smart city domains and enablers; 24 strategic objectives, 50 programs, and 101 projects were developed with the support of 183 smart city stakeholder entities and based on 125 citizen persona profiles and last one-year social media analysis. In conclusion, the followed methodology helps cities to identify and prioritize their needs and plan for long-term sustainable development, despite limited resources.

Keywords: needs-based, manifest, roadmap, smart city, top-down approach

Procedia PDF Downloads 217

Authors: Titin Handayani, Adi Mulyanto, Fajar Eko Priyanto

Abstract:

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

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

Procedia PDF Downloads 219

Authors: Sabrina Ladjama, Aicha Rizi, Azzedine Abbaci

Abstract:

In this work, we use the crossover model to formulate a comprehensive fundamental equation of state for the thermodynamic properties for several n-alkanes in the critical region that extends to the classical region. This equation of state is constructed on the basis of comparison of selected measurements of pressure-density-temperature data, isochoric and isobaric heat capacity. The model can be applied in a wide range of temperatures and densities around the critical point for n-heptane. It is found that the developed model represents most of the reliable experimental data accurately.

Keywords: crossover model, critical region, fundamental equation, n-heptane

Procedia PDF Downloads 480

Authors: Bao Chen, Frederic Kuznik, Matthieu Horgnies, Kevyn Johannes, Vincent Morin, Edouard Gengembre

Abstract:

The contradiction between energy consumption, environment protection, and social development is increasingly intensified during recent decade years. At the same time, as avoiding fossil-fuels-thirsty, people turn their view on the renewable green energy, such as solar energy, wind power, hydropower, etc. However, due to the unavoidable mismatch on geography and time for production and consumption, energy storage seems to be one of the most reasonable solutions to enlarge the use of renewable energies. Thermal energy storage (TES), a branch of energy storage solution, mainly concerns the capture, storage and consumption of thermal energy for later use in different scales (individual house, apartment, district, and city). In TES research field, sensible heat and latent heat storage have been widely studied and presented at an advanced stage of development. Compared with them, thermochemical energy storage is still at initial phase but provides a relatively higher theoretical energy density and a long shelf life without heat dissipation during storage. Among thermochemical energy storage materials, inorganic pure or composite compounds like micro-porous silica gel, SrBr₂ hydrate and MgSO₄-Zeolithe have been reported as promising to be integrated into thermal energy storage systems. However, the cost of these materials, one of main obstacles, may hinder the wide use of energy storage systems in real application scales (individual house, apartment, district and even city). New studies on ettringite show promising application for thermal energy storage since its high energy density and large resource from cementitious materials. Ettringite, or calcium trisulfoaluminate hydrate, of which chemical formula is 3CaO∙Al₂O₃∙3CaSO₄∙32H₂O, or C₆AS̅₃H₃₂ as known in cement chemistry notation, is one of the most important members of AFt group. As a common compound in hydrated cements, ettringite has been widely studied for its performances in construction but barely known as a thermochemical material. For this study, we summarize available data about the structure and properties of ettringite and its metastable phase (meta-ettringite), including the processes of hydration, thermal conversion and carbonation durability for thermal energy storage.

Keywords: building materials, ettringite, meta-ettringite, thermal energy storage

Procedia PDF Downloads 216

Authors: Abdela Bulbula

Abstract:

Background: Marek’s disease virus is a devastating infection, causing high morbidity and mortality in chickens in Ethiopia. Methods: The current study was conducted from March to November, 2021 with the general objective of performing antemortem and postmortem, isolation, and molecular detection of Marek’s disease virus from outbreak cases in southwestern Ethiopia. Accordingly, based on outbreak information reported from the study sites namely, Bedelle, Yayo, and Bonga towns in southwestern Ethiopia, 50 sick chickens were sampled. The backyard and intensive farming systems of chickens were included in the sampling and priorities were given for chickens that showed clinical signs that are characteristics of Marek’s disease. Results: By clinical examinations, paralysis of legs and wings, gray eye, loss of weight, difficulty in breathing, and depression were recorded on all chickens sampled for this study and death of diseased chickens was observed. In addition, enlargement of the spleen and gross lesions of the liver and heart were recorded during postmortem examination. The death of infected chickens was observed in both vaccinated and non-vaccinated flocks. Out of 50 pooled feather follicle samples, Marek’s disease virus was isolated from 14/50 (28%) by cell culture method and out of six tissue samples, the virus was isolated from 5/6(83.30%). By Real time polymerization chain reaction technique, which was targeted to detect the Meq gene, Marek’s disease virus was detected from 18/50 feather follicles which accounts for 36% of sampled chickens. Conclusion: In general, the current study showed that the circulating Marek’s disease virus in southwestern Ethiopia was caused by the oncogenic Gallid herpesvirus-2 (Serotype-1). Further research on molecular characterization of revolving virus in current and other regions is recommended for effective control of the disease through vaccination.

Keywords: Ethioi, Marek's disease, isolation, molecular

Procedia PDF Downloads 76

Authors: N. Al-Orfi, M. S. El-Shahawi, A. S. Bashammakh

Abstract:

The electrochemical response of glassy carbon electrode (GCE) for the sensitive and selective determination of dianabol steroid (DS) in phosphate, Britton-Robinson (B-R) and HEPES buffers of pH 2.0 - 11, 2.0 - 11 and 6.2 - 8.0, respectively using cyclic voltammetry (CV) and differential pulse- adsorptive cathodic stripping voltammetry (DP-CSV) at bare GCE was studied. The dependence of the CV response of the developed cathodic peak potential (Ep, c), peak current (ip, c) and the current function (ip, c / υ1/2) on the scan rate (υ) at the bare GCE revealed the occurrence of electrode coupled chemical reaction of EC type mechanism. The selectivity of the proposed method was assessed in the presence of high concentrations of major interfering species e.g. uric acid, ascorbic acid, citric acid, glucose, fructose, sucrose, starch and ions Na+, K+, PO4-3, NO3- and SO42-. The recovery of the method was not significant where t(critical)=2.20 > texp=1.81-1.93 at 95% confidence. The analytical application of the sensor for the quantification of DS in biological fluids as urine was investigated. The results were demonstrated as recovery percentages in the range 95±2.5-97±4.7% with relative standard deviation (RSD) of 0.5-1.5%.

Keywords: dianabol, determination, modified electrode, urine

Procedia PDF Downloads 279

Authors: Ljiljana Stojković, Manja Zec, Maja Zivkovic, Maja Bundalo, Marija Glibetić, Dragan Alavantić, Aleksandra Stankovic

Abstract:

Cardiovascular disease (CVD) is associated with alterations in DNA methylation, the latter modulated by dietary polyphenols. The present pilot study (part of the original clinical study registered as NCT02800967 at www.clinicaltrials.gov) aimed to investigate the impact of 4-week daily consumption of polyphenol-rich Aronia melanocarpa juice on Long Interspersed Nucleotide Element-1 (LINE-1) methylation in peripheral blood leukocytes, in subjects (n=34, age of 41.1±6.6 years) at moderate CVD risk, including an increased body mass index, central obesity, high normal blood pressure and/or dyslipidemia. The goal was also to examine whether factors known to affect DNA methylation, such as folate intake levels, MTHFR C677T gene variant, as well as the anthropometric and metabolic parameters, modulated the LINE-1 methylation levels upon consumption of polyphenol-rich Aronia juice. The experimental analysis of LINE-1 methylation was done by the MethyLight method. MTHFR C677T genotypes were determined by the polymerase chain reaction-restriction fragment length polymorphism method. Folate intake was assessed by processing the data from the food frequency questionnaire and repeated 24-hour dietary recalls. Serum lipid profile was determined by using Roche Diagnostics kits. The statistical analyses were performed using the Statistica software package. In women, after vs. before the treatment period, a significant decrease in LINE-1 methylation levels was observed (97.54±1.50% vs. 98.39±0.86%, respectively; P=0.01). The change (after vs. before treatment) in LINE-1 methylation correlated directly with MTHFR 677T allele presence, average daily folate intake and the change in serum low-density lipoprotein cholesterol, while inversely with the change in serum triacylglycerols (R=0.72, R2=0.52, adjusted R2=0.36, P=0.03). The current results imply potential cardioprotective effects of habitual polyphenol-rich Aronia juice consumption achieved through the modifications of DNA methylation pattern in subjects at CVD risk, which should be further confirmed. Hence, the precision nutrition-driven modulations of DNA methylation may become targets for new approaches in the prevention and treatment of CVD.

Keywords: Aronia melanocarpa, cardiovascular risk, LINE-1, methylation, peripheral blood leukocytes, polyphenol

Procedia PDF Downloads 200

Authors: Abubakar Sadiq Mensah

Abstract:

The Knowledge of the population growth of a nation is paramount to national planning. The population of a place is studied and a model developed over a period of time, Matrices is used to form model for population growth. The eigenvalue ƛ of the matrix A and its corresponding eigenvector X is such that AX = ƛX is calculated. The stable age distribution of the population is obtained using the eigenvalue and the characteristic polynomial. Hence, estimation could be made using eigenvalues and eigenvectors.

Keywords: eigenvalues, eigenvectors, population, growth/stability

Procedia PDF Downloads 528

Authors: Piyawan Sunasuan, Thiranan Pansuppawat, Mananya Manaratchasak, Maream Nillapun

Abstract:

This research aims to guide the development of the intensive English program for graduate students. The objectives are 1) to study the English skills in which needed for the graduate students and 2) to study the potential of the current course with the expected proficiency level. The samples are 46 graduate students enrolled in the ENG 102 and ENG 103 courses of the school year of 2019/2020 in semester one from the Silpakorn University, Sanamchandra Palace Campus, and two teachers. The researchers use 1) student survey, 2) teacher interview, and 3) focus group discussion among selected students. The data is analyzed by calculating the mean (x̅), the standard deviation, and document analysis. The findings show that nine skills are in the need of the course development; 1) academic writing 2) occupational purpose writing 3) communicative reading 4) occupational purpose reading 5) academic speaking 6) occupational purpose speaking 7) occupational purpose listening 8) academic listening and 9) communicative listening. The current course does not meet the expectation on a high level but has potential.

Keywords: English for academic purposes, English for communication, English for occupational purposes, intensive English

Procedia PDF Downloads 151

Authors: Tsai Yu-hsin, Chung Yi-Hsin

Abstract:

The employment of an HSR system, resulting in elevation in the inter-city/-region accessibility, is likely to promote spatial interaction between places in the HSR and extended territory. The inter-city/-region travel via HSR could be, among others, affected by the land use, transportation, and location of the HSR station at both trip origin and destination ends. However, relatively few insights have been shed on these impacts and spatial patterns of the HSR travel. The research purposes, as phase one of a series of HSR related research, of this study are threefold: to analyze the general spatial patterns of HSR trips, such as the spatial distribution of trip origins and destinations; to analyze if specific land use, transportation characteristics, and trip characteristics affect HSR trips in terms of the use of HSR, the distribution of trip origins and destinations, and; to analyze the socio-economic characteristics of HSR travelers. With the Taiwan HSR starting operation in 2007, this study emphasizes on the intermediate-term impact of HSR, which is made possible with the population and housing census and industry and commercial census data and a station area intercept survey conducted in the summer 2014. The analysis will be conducted at the city, inter-city, and inter-region spatial levels, as necessary and required. The analysis tools include descriptive statistics and multivariate analysis with the assistance of SPSS, HLM and ArcGIS. The findings, on the one hand, can provide policy implications for associated land use, transportation plan and the site selection of HSR station. On the other hand, on the travel the findings are expected to provide insights that can help explain how land use and real estate values could be affected by HSR in following phases of this series of research.

Keywords: high speed rail, land use, travel, spatial pattern

Procedia PDF Downloads 465

Authors: Seyed Mehdi Razavi Khosroshahi

Abstract:

In recent years a great deal of efforts has been made to find natural derivative compounds to replace it's with synthetic drugs, herbicides or pesticides for management of human health and agroecosystem programs. This process can lead to a reduction in environmental harmful effects of synthetic chemicals. Xanthotoxin, as a furanocoumarin compound, found in some genera of the Apiaceae family of plants. The current work focuses on some xanthotoxin cytotoxicity and antipathogenic activities. The results indicated that xanthotoxin showed strong cytotoxic effects against LNCaP cell line with the IC₅₀ value of 0.207 mg/ml in a dose-dependent manner. After treatments of the cell line with 0.1 mg/ml of the compound, the viability of the cells was reached to zero. The current study revealed that xanthotoxin displayed strong antifungal activity against human or plant pathogen fungi, Aspergillus fumigatus, Aspegillusn flavus and Fusarum graminearum with minimum inhibitory concentration values of 52-68 µg/ml. The compound exhibited antibacterial effects on some Erwinia and Xanthomonas species of bacteria, as well

Keywords: Xanthomonas, cytotoxic, antipathogen, LNCaP, Aspergillus fumigatus, spegillusn flavus

Procedia PDF Downloads 143

Authors: Zhiwu Zheng, Prakhar Kumar, Sigurd Wagner, Naveen Verma, James C. Sturm

Abstract:

Soft robots have drawn great interest recently due to a rich range of possible shapes and motions they can take on to address new applications, compared to traditional rigid robots. Large-area electronics (LAE) provides a unique platform for creating soft robots by leveraging thin-film technology to enable the integration of a large number of actuators, sensors, and control circuits on flexible sheets. However, the rich shapes and motions possible, especially when interacting with complex environments, pose significant challenges to forming well-generalized and robust models necessary for robot design and control. In this work, we describe an analytical model for predicting the shape and locomotion of a flexible (steel-foil-based) piezoelectric-actuated 2D robot based on Euler-Bernoulli beam theory. It is nominally (unpowered) lying flat on the ground, and when powered, its shape is controlled by an array of piezoelectric thin-film actuators. Key features of the models are its ability to incorporate the significant effects of gravity on the shape and to precisely predict the spatial distribution of friction against the contacting surfaces, necessary for determining inchworm-type motion. We verified the model by developing a distributed discrete element representation of a continuous piezoelectric actuator and by comparing its analytical predictions to discrete-element robot simulations using PyBullet. Without gravity, predicting the shape of a sheet with a linear array of piezoelectric actuators at arbitrary voltages is straightforward. However, gravity significantly distorts the shape of the sheet, causing some segments to flatten against the ground. Our work includes the following contributions: (i) A self-consistent approach was developed to exactly determine which parts of the soft robot are lifted off the ground, and the exact shape of these sections, for an arbitrary array of piezoelectric voltages and configurations. (ii) Inchworm-type motion relies on controlling the relative friction with the ground surface in different sections of the robot. By adding torque-balance to our model and analyzing shear forces, the model can then determine the exact spatial distribution of the vertical force that the ground is exerting on the soft robot. Through this, the spatial distribution of friction forces between ground and robot can be determined. (iii) By combining this spatial friction distribution with the shape of the soft robot, in the function of time as piezoelectric actuator voltages are changed, the inchworm-type locomotion of the robot can be determined. As a practical example, we calculated the performance of a 5-actuator system on a 50-µm thick steel foil. Piezoelectric properties of commercially available thin-film piezoelectric actuators were assumed. The model predicted inchworm motion of up to 200 µm per step. For independent verification, we also modelled the system using PyBullet, a discrete-element robot simulator. To model a continuous thin-film piezoelectric actuator, we broke each actuator into multiple segments, each of which consisted of two rigid arms with appropriate mass connected with a 'motor' whose torque was set by the applied actuator voltage. Excellent agreement between our analytical model and the discrete-element simulator was shown for both for the full deformation shape and motion of the robot.

Keywords: analytical modeling, piezoelectric actuators, soft robot locomotion, thin-film technology

Procedia PDF Downloads 186

Authors: Shulamit Sternin

Abstract:

Athletes experience injuries that can have both a physical and psychological impact on the individual. In such instances, athletes are able to rely on the established field of sports psychology to facilitate holistic rehabilitation. Musicians, like athletes rely on their bodies to perform in much the same way athletes do and are also susceptible to injury. Due to the similar performative nature of succeeding as an athletes or a musician, these careers share many of the same primary psychological concerns and therefore it is reasonable that athletes and musicians may require similar rehabilitation post-injury. However, musicians face their own unique psychological challenges and understanding the needs of an injured athlete can serve as a foundation for understanding the injured musician but is not enough to fully rehabilitate an injured musician. The current research surrounding musicians and their injuries is primarily focused on physiological aspects of injury and rehabilitation; the psychological aspects have not yet received adequate attention resulting in poor musician rehabilitation post- injury. This review paper uses current models of psychological response to injury in athletes to draw parallels with the psychological response to injury in musicians. Search engines such as Medline and PsycInfo were systematically searched using specific key words, such as psychological response, injury, athlete, and musician. Studies that focused on post-injury psychology of either the musician or the athlete were included. Within the literature there is evidence to support psychological responses, unique to the musician, that are not accounted for by current models of response in athletes. The models of psychological response to injury in athletes are inadequate tools for application to the musician. Future directions for performance arts research that can fill the gaps in our understanding and modeling of musicians’ response to injury are discussed. A better understanding of the psychological impact of injuries on musicians holds significant implications for health care practitioners working with injured musicians. Understanding the unique barriers musicians face post-injury, and how support for this population must be tailored to properly suit musicians’ needs will aid in more holistic rehabilitation and a higher likelihood of musician’s returning to pre-injury performance levels.

Keywords: athlete, injury, musician, psychological response

Procedia PDF Downloads 209

Authors: Nasrin Nejatbakhsh, Anita Kaiser, Sander Hitzig, Colleen McGillivray

Abstract:

Following spinal cord injury (SCI), many individuals experience anxiety in adjusting to their lives, and its impacts on their sexuality. Research has demonstrated that regaining sexual function is a very high priority for individuals with SCI. Despite this, sexual health is one of the least likely areas of focus in rehabilitating individuals with SCI. There is currently a considerable gap in appropriate education and resources that address sexual health concerns and needs of people with spinal cord injury. Furthermore, the determinants of sexual health in individuals with SCI are poorly understood and thus poorly addressed. The purpose of this study was to improve current practices by informing a service delivery model that rehabilitation centers can adopt for appropriate delivery of their services. Methodology: We utilized qualitative methods in the form of a semi-structured interview containing open-ended questions to assess 1) sexual health concerns, 2) helpful strategies in current resources, 3) unhelpful strategies in current resources, and 4) Barriers to obtaining sexual health information. In addition to the interviews, participants completed surveys to identify socio-demographic factors. Data gathered was coded and evaluated for emerging themes and subthemes through a ‘code-recode’ technique. Results: We have identified several robust themes that are important for SCI sexual health resource development. Through analysis of these themes and their subthemes, several important concepts have emerged that could provide agencies with helpful strategies for providing sexual health resources. Some of the important considerations are that services be; anonymous, accessible, frequent, affordable, mandatory, casual and supported by peers. Implications: By incorporating the perspectives of individuals with SCI, the finding from this study can be used to develop appropriate sexual health services and improve access to information through tailored needs based program development.

Keywords: spinal cord injury, sexual health, determinants of health, resource development

Procedia PDF Downloads 255

Authors: Bihan Qaimari

Abstract:

In many areas of the world there are political conflicts the consequences of which have an inevitable impact on the educational system. Palestine is one such country where the experience of political conflict, going back over many years, has had a devastating effect on the development and maintenance of a stable educational environment for children and their teachers. Up to now there have been few studies that have focussed on the effects of living and working in a war zone on the professional identity of teachers. The aim of this study is to explore how the formation of Palestinian teachers’ professional identity is affected by their experience of the current political conflict its impact on the school social culture. In order to gain an in-depth understanding of the impact of political violence on the formation of the professional identity of Palestinian teachers, a qualitative multiple case-study approach was adopted which draws on sociocultural theories of identity formation. An initial study was first conducted in six schools and this was followed by an in-depth study of teachers working in three further primary schools. Data sources included participant observation, a research diary, semi-structured group and individual interviews. Grounded theory, constant-comparative methods, and discourse analysis procedures were used to interpret the data. The findings suggest that the Palestinian primary school teachers negotiate multiple conflicting identities through their every day experiences of political conflict and the schools’ social culture. This tension is formed as a result of the historical cultural meaning that teachers construct about themselves and within the current unstable and unsettling conditions that exist in their country. In addition, the data indicate that the geographical location of the schools in relation of their proximity to the events of the political conflict also had an influence on the degree of tension inherent in teachers’ professional identity. The study makes significant theoretical, practical, and methodical contributions to the study of the formation of teachers’ professional identity in countries affected by political conflict.

Keywords: identity, political conflict, Palestine, teacher's professional identity

Procedia PDF Downloads 414

Authors: Zi-Yan Chao

Abstract:

With the rapid development of urbanization and increasing demand for efficient transportation systems, the interaction between land use diversity and transportation resource allocation has become a critical issue in urban planning. Achieving a balance of land use types, such as residential, commercial, and industrial areas, is crucial role in ensuring social equity and sustainable urban development. Simultaneously, optimizing multimodal transportation networks, including bus, subway, and car routes, is essential for minimizing total travel time and costs, while ensuring fairness for all social groups, particularly in meeting the transportation needs of low-income populations. This study develops a bilevel programming model to address these challenges, with land use diversity as the foundation for measuring equity. The upper-level model maximizes land use diversity for balanced land distribution across regions. The lower-level model optimizes multimodal transportation networks to minimize travel time and costs while maintaining user equilibrium. The model also incorporates constraints to ensure fair resource allocation, such as balancing transportation accessibility and cost differences across various social groups. A solution approach is developed to solve the bilevel optimization problem, ensuring efficient exploration of the solution space for land use and transportation resource allocation. This study maximizes social equity by maximizing land use diversity and achieving user equilibrium with optimal transportation resource distribution. The proposed method provides a robust framework for addressing urban planning challenges, contributing to sustainable and equitable urban development.

Keywords: bilevel programming model, genetic algorithms, land use diversity, multimodal transportation optimization, social equity

Procedia PDF Downloads 28

Authors: M. Rahou, A. J. Andrews, G. Rosengarten

Abstract:

One of the main challenges in high-temperature solar thermal applications transfer concentrated solar radiation to the load with minimum energy loss and maximum overall efficiency. The use of a solar concentrator in conjunction with bundled optical fibres has potential advantages in terms of transmission energy efficiency, technical feasibility and cost-effectiveness compared to a conventional heat transfer system employing heat exchangers and a heat transfer fluid. In this paper, a theoretical and computer simulation method is described to estimate the net solar radiation transmission from a solar concentrator into and through optical fibres to a thermal application at the end of the fibres over distances of up to 100 m. A key input to the simulation is the angular distribution of radiation intensity at each point across the aperture plane of the optical fibre. This distribution depends on the optical properties of the solar concentrator, in this case, a parabolic mirror with a small secondary mirror with a common focal point and a point-focus Fresnel lens to give a collimated beam that pass into the optical fibre bundle. Since solar radiation comprises a broad band of wavelengths with very limited spatial coherence over the full range of spectrum only ray tracing models absorption within the fibre and reflections at the interface between core and cladding is employed, assuming no interference between rays. The intensity of the radiation across the exit plane of the fibre is found by integrating across all directions and wavelengths. Results of applying the simulation model to a parabolic concentrator and point-focus Fresnel lens with typical optical fibre bundle will be reported, to show how the energy transmission varies with the length of fibre.

Keywords: concentrated radiation, fibre bundle, parabolic dish, fresnel lens, transmission

Procedia PDF Downloads 570

Authors: Seyed Abolhasan Naeini, M. Mortezaee

Abstract:

Various factors such as the method of installation, the pile type, the pile material and the pile shape, can affect the final bearing capacity of a pile executed in the soil; among them, the method of installation is of special importance. The physical modeling is among the best options in the laboratory study of the piles behavior. Therefore, the current paper first presents and reviews the frustum confining vesel (FCV) as a suitable tool for physical modeling of deep foundations. Then, by describing the loading tests of two open-ended and closed-end steel piles, each of which has been performed in two methods, “with displacement" and "without displacement", the effect of end conditions and installation method on the final bearing capacity of the pile is investigated. The soil used in the current paper is silty sand of Firoozkooh. The results of the experiments show that in general the without displacement installation method has a larger bearing capacity in both piles, and in a specific method of installation the closed ended pile shows a slightly higher bearing capacity.

Keywords: physical modeling, frustum confining vessel, pile, bearing capacity, installation method

Procedia PDF Downloads 155

Authors: Ime R. Udotong, Ofonime U. M. John, Justina I. R. Udotong

Abstract:

Ibeno, Nigeria hosts the operational base of Mobil Producing Nigeria Unlimited (MPNU), a subsidiary of ExxonMobil and the current highest oil and condensate producer in Nigeria. Besides MPNU, other multinational oil companies like Shell Petroleum Development Company Ltd, Elf Petroleum Nigeria Ltd and Nigerian Agip Energy, a subsidiary of ENI E&P operate onshore, on the continental shelf and deep offshore of the Atlantic Ocean in Ibeno, Nigeria, respectively. This study was designed to carry out the survey of the oil impacted sites in Ibeno, Nigeria. A combinations of electrical resistivity (ER), ground penetrating radar (GPR) and physico-chemical as well as microbiological characterization of soils and water samples from the area were carried out. Results obtained revealed that there have been hydrocarbon contaminations of this environment by past crude oil spills as observed from significant concentrations of THC, BTEX and heavy metal contents in the environment. Also, high resistivity values and GPR profiles clearly showing the distribution, thickness and lateral extent of hydrocarbon contamination as represented on the radargram reflector tones corroborates previous significant oil input. Contaminations were of varying degrees, ranging from slight to high, indicating levels of substantial attenuation of crude oil contamination over time. Hydrocarbon pollution of the study area was confirmed by the results of soil and water physico-chemical and microbiological analysis. The levels of THC contamination observed in this study are indicative of high levels of crude oil contamination. Moreover, the display of relatively lower resistivities of locations outside the impacted areas compared to resistivity values within the impacted areas, the 3-D Cartesian images of oil contaminant plume depicted by red, light brown and magenta for high, low and very low oil impacted areas, respectively as well as the high counts of hydrocarbonoclastic microorganisms in excess of 1% confirmed significant recent pollution of the study area.

Keywords: oil-polluted sites, physico-chemical analyses, microbiological characterization, geotechnical investigations, total hydrocarbon content

Procedia PDF Downloads 391

Authors: Uma U. Uma, Uzoechi Laz

Abstract:

Protection of equipment insulation against lightning over voltages and selection of lightning arrester that will discharge at lower voltage level than the voltage required to breakdown the electrical equipment insulation is examined. The objectives of this paper are to design a computer based model using standard equations for the selection of appropriate lightning arrester with the lowest rated surge arrester that will provide adequate protection of equipment insulation and equally have a satisfactory service life when connected to a specified line voltage in power system network. The effectiveness and non-effectiveness of the earthing system of substation determine arrester properties. MATLAB program with GUI (graphic user interphase) its subprogram is used in the development of the model for the determination of required parameters like voltage rating, impulse spark over voltage, power frequency spark over voltage, discharge current, current rating and protection level of lightning arrester of a specified voltage level of a particular line.

Keywords: lightning arrester, GUIs, MatLab program, computer based model

Procedia PDF Downloads 422

Authors: Sunday Olufemi Adesogan

Abstract:

The supply of potable water at least is a very important index in national development. Water tariffs depend on the treatment cost which carries the highest percentage of the total operation cost in any water supply scheme. In order to keep water tariffs as low as possible, treatment costs have to be minimized. The University of Ibadan, Nigeria, water supply scheme consists of a treatment plant with three distribution stations (Amina way, Kurumi and Lander) and two raw water supply sources (Awba dam and Eleyele dam). An operational study of the scheme was carried out to ascertain the efficiency of the supply of potable water on the campus to justify the need for water supply schemes in tertiary institutions. The study involved regular collection, processing and analysis of periodic operational data. Data collected include supply reading (water production on daily basis) and consumers metered reading for a period of 22 months (October 2013 - July 2015), and also collected, were the operating hours of both plants and human beings. Applying the required mathematical equations, total loss was determined for the distribution system, which was translated into monetary terms. Adequacies of the operational functions were also determined. The study revealed that water supply scheme is justified in tertiary institutions. It was also found that approximately 10.7 million Nigerian naira (N) is lost to leakages during the 22-month study period; the system’s storage capacity is no longer adequate, especially for peak water production. The capacity of the system as a whole is insufficient for the present university population and that the existing water supply system is not being operated in an optimal manner especially due to personnel, power and system ageing constraints.

Keywords: development, panacea, supply, water

Procedia PDF Downloads 214

Authors: Fanyuan Shao, Wei Liu, Deli Gao

Abstract:

Polycrystalline diamond composite (PDC) cutter is made of diamond powder as raw material, cobalt metal or non-metallic elements as a binder, mixed with WC cemented carbide matrix assembly, through high temperature and high-pressure sintering. PDC bits with PDC cutters are widely used in oil and gas drilling because of their high hardness, good wear resistance and excellent impact toughness. And PDC cutter is the main cutting tool of bit, which seriously affects the service of the PDC bit. The wear resistance of the PDC cutter is measured by cutting granite with a vertical turret lathe (VTL). This experiment can achieve long-distance cutting to obtain the relationship between the wear resistance of the PDC cutter and cutting distance, which is more closely to the real drilling situation. Load cell and 3D optical profiler were used to obtain the value of cutting forces and wear area, respectively, which can also characterize the damage and wear of the PDC cutter. PDC cutters were cut via electrical discharge machining (EDM) and then flattened and polished. A scanning electron microscope (SEM) was used to observe the distribution of binder cobalt and the size of diamond particles in a diamond PDC cutter. The cutting experimental results show that the wear area of the PDC cutter has a good linear relationship with the cutting distance. Simultaneously, the larger the wear area is and the greater the cutting forces are required to maintain the same cutting state. The size and distribution of diamond particles in the polycrystalline diamond layer have a great influence on the wear resistance of the diamond layer. And PDC cutter with fine diamond grains shows more wear resistance than that with coarse grains. The deep leaching process is helpful to reduce the effect of binder cobalt on the wear resistance of the polycrystalline diamond layer. The experimental study can provide an important basis for the application of PDC cutters in oil and gas drilling.

Keywords: polycrystalline diamond compact, scanning electron microscope, wear resistance, cutting distance

Procedia PDF Downloads 201