Search results for: aspect ratio (L/b)
5238 Disclosure Experience of Working People Living with HIV/AIDS in Nigeria: A Qualitative Research
Authors: Dorcas I. Adeoye
Abstract:
Disclosure experience of people living with HIV/AIDS has been a public health concern, it has also been attributed to effective way of limiting the spread of the disease. However, among working people living with HIV, it is a great issue that attracts several consequences, it is also a way of managing HIV and balancing their emotional, physical and social aspect of life. The economic, social and political aspect has been affected since the emergent of HIV. It is also not a medical problem that only needs a medical approach; it is a psychological problem that needs not to be ignored. Work attitude model and consequential theory were used to understanding the experience of disclosure or non-disclosure in the workplace. Work attitude model explains the job satisfaction and the organisational commitment of an employee that have effect on the decision and well-being in the workplace; it can also influence a decision to disclosure one’s health condition, however, consequential theory comes to play when a decision is being made, either to disclose or not, and that will attract consequences (either negative or positive) in which ever decision made. A phenomenological study was conducted among employed people that are infected with HIV/AIDS in a south-eastern region of Nigeria where unemployment rate is high. A one-to-one semi-structured interview was used to gather in-depth information about the experience of 20 working people living with HIV. Participants were recruited in a hospital and for some, hospital serves as their workplace. The outcome of the research shows that participants’ experiences vary. One thing that stood out and was found similar among all participants including participants that have disclosed, planning to disclose, or never intended to disclose, is that workplace is a place not to be trusted despite the positive outcomes disclosure could give in the workplace, and disclosure decision needs to be carefully taken. The study was concluded with recommendations that cover various aspects; however, clearer policies should be followed by all organisations to protect people living with HIV in the workplace.Keywords: disclosure, employment, HIV/AIDS, Nigeria, workplace
Procedia PDF Downloads 2975237 A Study on the Effect of Cod to Sulphate Ratio on Performance of Lab Scale Upflow Anaerobic Sludge Blanket Reactor
Authors: Neeraj Sahu, Ahmad Saadiq
Abstract:
Anaerobic sulphate reduction has the potential for being effective and economically viable over conventional treatment methods for the treatment of sulphate-rich wastewater. However, a major challenge in anaerobic sulphate reduction is the diversion of a fraction of organic carbon towards methane production and some minor problem such as odour problems, corrosion, and increase of effluent chemical oxygen demand. A high-rate anaerobic technology has encouraged researchers to extend its application to the treatment of complex wastewaters with relatively low cost and energy consumption compared to physicochemical methods. Therefore, the aim of this study was to investigate the effects of COD/SO₄²⁻ ratio on the performance of lab scale UASB reactor. A lab-scale upflow anaerobic sludge blanket (UASB) reactor was operated for 170 days. In which first 60 days, for successful start-up with acclimation under methanogenesis and sulphidogenesis at COD/SO₄²⁻ of 18 and were operated at COD/SO₄²⁻ ratios of 12, 8, 4 and 1 to evaluate the effects of the presence of sulfate on the reactor performance. The reactor achieved maximum COD removal efficiency and biogas evolution at the end of acclimation (control). This phase lasted 53 days with 89.5% efficiency. The biogas was 0.6 L/d at (OLR) of 1.0 kg COD/m³d when it was treating synthetic wastewater with effective volume of reactor as 2.8 L. When COD/SO₄²⁻ ratio changed from 12 to 1, slight decrease in COD removal efficiencies (76.8–87.4%) was observed, biogas production decreased from 0.58 to 0.32 L/d, while the sulfate removal efficiency increased from 42.5% to 72.7%.Keywords: anaerobic, chemical oxygen demand, organic loading rate, sulphate, up-flow anaerobic sludge blanket reactor
Procedia PDF Downloads 2135236 Development of Standard Thai Appetizer in Rattanakosin Era‘s Standard: Case Study of Thai Steamed Dumpling
Authors: Nunyong Fuengkajornfung, Pattama Hirunyophat, Tidarat Sanphom
Abstract:
The objectives of this research were: To study of the recipe standard of Thai steamed dumpling, to study the ratio of modified starch in Thai steamed dumpling, to study chemical elements analyzing and Escherichia coli in Thai steamed dumpling. The experimental processes were designed in two stages as follows: To study the recipe standard of Thai steamed dumpling and to study the ratio of rice flour: modify starch by three levels 90:10, 73:30, and 50:50. The evaluation test used 9 Points Hedonic Scale method by the sensory evaluation test such as color, smell, taste, texture and overall liking. An experimental by Randomized Complete Block Design (RCBD). The statistics used in data analyses were means, standard deviation, one-way ANOVA and Duncan’s New Multiple Range Test. Regression equation, at a statistically significant level of .05. The results showed that the recipe standard was studied from three recipes by the sensory evaluation test such as color, odor, taste, spicy, texture and total acceptance. The result showed that the recipe standard of second was suitably to development. The ratio of rice flour: modified starch had 3 levels 90:10, 73:30, and 50:50 which the process condition of 50:50 had well scores (like moderately to like very much; used 9 Points Hedonic Scale method for the sensory test). Chemical elements analyzing, it showed that moisture 58.63%, fat 5.45%, protein 4.35%, carbohydrate 30.45%, and Ash 1.12%. The Escherichia coli is not found in lab testing.Keywords: Thai snack in Rattanakosin era, Thai steamed dumpling, modify starch, recipe standard
Procedia PDF Downloads 3205235 Impact of Risk Management Practices on Company Performance
Authors: Syed Atif Ali, Farzan Yahya
Abstract:
This research paper covers the issue of risk management impact on the company performance. Degree of financial leverage (DFL), degree of operating leverage (DOL) and the working capital ratio (WCR) are taken as independent variables which are the representative of risk and the earning price per share (EPS), return on assets (ROA), return on equity (ROE), Sales and Net profits which are the representative of performance. Last 10 years (2004-2013) of Cement sector of Pakistan data is chosen as sample for analyze their relations by multiple regression technique. Through analyses, it is found that WCR impact adequately on the company performance because if company has enough liquidity than it perform its operations smoothly and enhance its performance very well. DFL should be control moderately because enough DFL leads performance of company downward. On the other hand, the DOL should be less because it causes the less profitability for a company from its operations.Keywords: degree of financial leverage (DFL), degree of operating leverage (DOL), working capital ratio (WCR), earning per share (EPS), return on equity (ROE), return on assets (ROA)
Procedia PDF Downloads 4455234 Effect of Soaking Period of Clay on Its California Bearing Ratio Value
Authors: Robert G. Nini
Abstract:
The quality of road pavement is affected mostly by the type of sub-grade which is acting as road foundation. The roads degradation is related to many factors especially the climatic conditions, the quality, and the thickness of the base materials. The thickness of this layer depends on its California Bearing Ratio (CBR) test value which by its turn is highly affected by the quantity of water infiltrated under the road after heavy rain. The capacity of the base material to drain out its water is predominant factor because any change in moisture content causes change in sub-grade strength. This paper studies the effect of the soaking period of soil especially clay on its CBR value. For this reason, we collected many clayey samples in order to study the effect of the soaking period on its CBR value. On each soil, two groups of experiments were performed: main tests consisting of Proctor and CBR test from one side and from other side identification tests consisting of other tests such as Atterberg limits tests. Each soil sample was first subjected to Proctor test in order to find its optimum moisture content which will be used to perform the CBR test. Four CBR tests were performed on each soil with different soaking period. The first CBR was done without soaking the soil sample; the second one with two days soaking, the third one with four days soaking period and the last one was done under eight days soaking. By comparing the results of CBR tests performed with different soaking time, a more detailed understanding was given to the role of the water in reducing the CBR of soil. In fact, by extending the soaking period, the CBR was found to be reduced quickly the first two days and slower after. A precise reduction factor of the CBR in relation with soaking period was found at the end of this paper.Keywords: California Bearing Ratio, clay, proctor test, soaking period, sub-grade
Procedia PDF Downloads 1275233 Sleep Disturbance in Indonesian School-Aged Children and Its Relationship to Nutritional Aspect
Authors: William Cheng, Rini Sekartini
Abstract:
Background: Sleep is essential for children because it provides enhancement for the neural system activities that give physiologic effects for the body to support growth and development. One of the modifiable factors that relates with sleep is nutrition, which includes nutritional status, iron intake, and magnesium intake. Nutritional status represents the balance between nutritional intake and expenditure, while iron and magnesium are micronutrients that are related to sleep regulation. The aim of this study is to identify prevalence of sleep disturbance among Indonesian children and to evaluate its relation with aspect to nutrition. Methods : A cross-sectional study involving children aged 5 to 7-years-old in an urban primary health care between 2012 and 2013 was carried out. Related data includes anthropometric status, iron intake, and magnesium intake. Iron and magnesium intake was obtained by 24-hours food recall procedure. Sleep Disturbance Scale for Children (SDSC) was used as the diagnostic tool for sleep disturbance, with score under 39 indicating presence of problem. Results: Out of 128 school-aged children included in this study, 28 (23,1%) of them were found to have sleep disturbance. The majority of children had good nutritional status, with only 15,7% that were severely underweight or underweight, and 12,4% that were identified as stunted. On the contrary, 99 children (81,8%) were identified to have inadequate magnesium intake and 56 children (46,3%) with inadequate iron intake. Our analysis showed there was no significant relation between all of the nutritional status indicators and sleep disturbance (p>0,05%). Moreover, inadequate iron and magnesium intake also failed to prove significant relation with sleep disturbance in this population. Conclusion: Almost fourth of school-aged children in Indonesia were found to have sleep disturbance and further study are needed to overcome this problem. According to our finding, there is no correlation between nutritional status, iron intake, magnesium intake, and sleep disturbance.Keywords: iron intake, magnesium intake, nutritional status, school-aged children, sleep disturbance
Procedia PDF Downloads 4595232 Investigating Secondary Students’ Attitude towards Learning English
Authors: Pinkey Yaqub
Abstract:
The aim of this study was to investigate secondary (grades IX and X) students’ attitudes towards learning the English language based on the medium of instruction of the school, the gender of the students and the grade level in which they studied. A further aim was to determine students’ proficiency in the English language according to their gender, the grade level and the medium of instruction of the school. A survey was used to investigate the attitudes of secondary students towards English language learning. Simple random sampling was employed to obtain a representative sample of the target population for the research study as a comprehensive list of established English medium schools, and newly established English medium schools were available. A questionnaire ‘Attitude towards English Language Learning’ (AtELL) was adapted from a research study on Libyan secondary school students’ attitudes towards learning English language. AtELL was reviewed by experts (n=6) and later piloted on a representative sample of secondary students (n= 160). Subsequently, the questionnaire was modified - based on the reviewers’ feedback and lessons learnt during the piloting phase - and directly administered to students of grades 9 and 10 to gather information regarding their attitudes towards learning the English language. Data collection spanned a month and a half. As the data were not normally distributed, the researcher used Mann-Whitney tests to test the hypotheses formulated to investigate students’ attitudes towards learning English as well as proficiency in the language across the medium of instruction of the school, the gender of the students and the grade level of the respondents. Statistical analyses of the data showed that the students of established English medium schools exhibited a positive outlook towards English language learning in terms of the behavioural, cognitive and emotional aspects of attitude. A significant difference was observed in the attitudes of male and female students towards learning English where females showed a more positive attitude in terms of behavioural, cognitive and emotional aspects as compared to their male counterparts. Moreover, grade 10 students had a more positive attitude towards learning English language in terms of behavioural, cognitive and emotional aspects as compared to grade 9 students. Nonetheless, students of newly established English medium schools were more proficient in English as gauged by their examination scores in this subject as compared to their counterparts studying in established English medium schools. Moreover, female students were more proficient in English while students studying in grade 9 were less proficient in English than their seniors studying in grade 10. The findings of this research provide empirical evidence to future researchers wishing to explore the relationship between attitudes towards learning language and variables such as the medium of instruction of the school, gender and the grade level of the students. Furthermore, policymakers might revisit the English curriculum to formulate specific guidelines that promote a positive and gender-balanced outlook towards learning English for male and female students.Keywords: attitude, behavioral aspect of attitude, cognitive aspect of attitude, emotional aspect of attitude
Procedia PDF Downloads 2245231 Earthquakes' Magnitude and Density Controls by Mechanical Stratigraphy in the Zagros, Iran
Authors: Asaad Pireh
Abstract:
The Zagros fold and thrust belt is one of the most active seismic zones of Iran where hosts many people and considerable oil and gas resources. The Zagros fold and thrust belt, based on its stratigraphy has been divided into three provinces. Mechanical stratigraphy of these provinces is different together. Statistical analyses all of earthquakes which has happened in the Zagros fold and thrust belt from 1964 up to December 2014, shows that strong earthquakes have occurred within the southeastern part of these subdivisions which has a smaller ratio of incompetent to competent thickness and in the northwestern part of these subdivisions which has a greater ratio of incompetent to competent thickness has occurred the weakest earthquakes. The southeastern part of the Zagros has a higher seismic risk and northwestern part of these fold belt have a lower seismic risk.Keywords: earthquake, mechanical stratigraphy, seismic risk, Zagros
Procedia PDF Downloads 1415230 A Data-Driven Platform for Studying the Liquid Plug Splitting Ratio
Authors: Ehsan Atefi, Michael Grigware
Abstract:
Respiratory failure secondary to surfactant deficiency resulting from respiratory distress syndrome is considered one major cause of morbidity in preterm infants. Surfactant replacement treatment (SRT) is considered an effective treatment for this disease. Here, we introduce an AI-mediated approach for estimating the distribution of surfactant in the lung airway of a newborn infant during SRT. Our approach implements machine learning to precisely estimate the splitting ratio of a liquid drop during bifurcation at different injection velocities and patient orientations. This technique can be used to calculate the surfactant residue remaining on the airway wall during the surfactant injection process. Our model works by minimizing the pressure drop difference between the two airway branches at each generation, subject to mass and momentum conservation. Our platform can be used to generate feedback for immediately adjusting the velocity of injection and patient orientation during SRT.Keywords: respiratory failure, surfactant deficiency, surfactant replacement, machine learning
Procedia PDF Downloads 1185229 Performance of Armchair Graphene Nanoribbon Resonant Tunneling Diode under Uniaxial Strain
Authors: Milad Zoghi, M. Zahangir Kabir
Abstract:
Performance of armchair graphene nanoribbon (AGNR) resonant tunneling diodes (RTD) alter if they go under strain. This may happen due to either using stretchable substrates or real working conditions such as heat generation. Therefore, it is informative to understand how mechanical deformations such as uniaxial strain can impact the performance of AGNR RTDs. In this paper, two platforms of AGNR RTD consist of width-modified AGNR RTD and electric-field modified AGNR RTD are subjected to both compressive and tensile uniaxial strain ranging from -2% to +2%. It is found that characteristics of AGNR RTD markedly change under both compressive and tensile strain. In particular, peak to valley ratio (PVR) can be totally disappeared upon strong enough strain deformation. Numerical tight binding (TB) coupled with Non-Equilibrium Green's Function (NEGF) is derived for this study to calculate corresponding Hamiltonian matrices and transport properties.Keywords: armchair graphene nanoribbon, resonant tunneling diode, uniaxial strain, peak to valley ratio
Procedia PDF Downloads 1735228 The Effect of Saccharomyces cerevisiae Live Yeast Culture on Microbial Nitrogen Supply to Small Intestine in Male Kivircik Yearlings Fed with Different Ratio of Forage and Concentrate
Authors: Nurcan Cetinkaya, Nadide Hulya Ozdemir
Abstract:
The aim of the study was to investigate the effect of Saccharomyces cerevisiae (SC) live yeast culture on microbial protein supply to the small intestine in Kivircik male yearlings when fed with different ratio of forage and concentrate diets. Four Kivircik male yearlings with permanent rumen canula were used in the experiment. . The treatments were allocated to a 4x4 Latin square design. Diet I consisted of 70% alfalfa hay and 30% concentrate, Diet II consisted of 30% alfalfa hay and 70% concentrate, Diet I and II were supplemented with a SC. Daily urine was collected and stored at -20°C until analysis. Calorimetric methods were used for the determination of urinary allantoin and creatinin levels. The estimated microbial N supply to small intestine for Diets I, I+SC, II and II+SC were 2.51, 2.64, 2.95 and 3.43 g N/d respectively. Supplementation of Diets I and II with SC significantly affected the allantoin levels in µmol/W0. 75 (p<0.05). Mean creatinine values in µmol/W0. 75 and allantoin:creatinin ratios were not significantly different among diets. In conclusion, supplementation with SC live yeast culture had a significant effect on urinary allantoin excretion and microbial protein supply to small intestine in Kivircik yearlings fed with high concentrate Diet II (P<0.05). Hence urinary allantoin excretion may be used as a tool for estimating microbial protein supply in Kivircık yearlings. However, further studies are necessary to understand the metabolism of Saccharomyces cerevisiae live yeast culture with different forage: concentrate ratio in Kıvırcık Yearlings.Keywords: allantoin, creatinin, Kivircik yearling, microbial nitrogen, Saccharomyces cerevisia
Procedia PDF Downloads 4075227 Practical Ways to Acquire the Arabic Language through Electronic Means
Authors: Hondozi Jahja
Abstract:
There is an obvious need to learn Arabic language and teach it to other speakers through the new curricula. The idea is to bridge the gap between theory and practice. To that end, we have sought to offer some means of help to master the Arabic language, in addition to our efforts to apply these means, enriching the culture of the student and develop his vocabulary. There is no doubt that taking care of the practical aspect of the grammar was our constant goal, and this particular aspect is what builds the student’s positive values and refine his taste and develop his language. In addressing these issues, we have adopted a school-based approach based primarily on the active and positive participation of the student. The theoretical linguistic issues - in our opinion - are not a primary goal, but the goal is to be used them by students through speaking and applying them. Among the objectives of this research is to establish the basic language skills of the students using new means that help the student to acquire these skills and apply them in various subjects of interest in his progress and development. Unfortunately, some of our students consider the grammar as ‘difficult’, ‘complex’ and ‘heavy’ in itself. This is one of the obstacles that stand in the way of their desired results. As a consequence, they end up talking – mumbling - about the difficulties they face in applying those rules. Therefore, some of our students finish their university studies and are unable to express what they feel using language correctly. For this purpose, we have sought in this research to follow a new integrated approach, which is to study the grammar of the language through modern means of the consolidation of the principle of functional language, and that the rule implies to control tongues and linguistic expressions properly. This research is a result of a practical experience as a teacher of Arabic language for non-native speakers at the ‘Hassan Pristina’ University, located in Pristina, the capital of Kosovo and at the Qatar Training Center since its establishment in 2012.Keywords: arabic, applied methods, acquire, learning
Procedia PDF Downloads 1495226 First Formaldehyde Retrieval Using the Raw Data Obtained from Pandora in Seoul: Investigation of the Temporal Characteristics and Comparison with Ozone Monitoring Instrument Measurement
Abstract:
In this present study, for the first time, we retrieved the Formaldehyde (HCHO) Vertical Column Density (HCHOVCD) using Pandora instruments in Seoul, a megacity in northeast Asia, for the period between 2012 and 2014 and investigated the temporal characteristics of HCHOVCD. HCHO Slant Column Density (HCHOSCD) was obtained using the Differential Optical Absorption Spectroscopy (DOAS) method. HCHOSCD was converted to HCHOVCD using geometric Air Mass Factor (AMFG) as Pandora is the direct-sun measurement. The HCHOVCDs is low at 12:00 Local Time (LT) and is high in the morning (10:00 LT) and late afternoon (16:00 LT) except for winter. The maximum (minimum) values of Pandora HCHOVCD are 2.68×1016 (1.63×10¹⁶), 3.19×10¹⁶ (2.23×10¹⁶), 2.00×10¹⁶ (1.26×10¹⁶), and 1.63×10¹⁶ (0.82×10¹⁶) molecules cm⁻² in spring, summer, autumn, and winter, respectively. In terms of seasonal variations, HCHOVCD was high in summer and low in winter which implies that photo-oxidation plays an important role in HCHO production in Seoul. In comparison with the Ozone Monitoring Instrument (OMI) measurements, the HCHOVCDs from the OMI are lower than those from Pandora. The correlation coefficient (R) between monthly HCHOVCDs values from Pandora and OMI is 0.61, with slop of 0.35. Furthermore, to understand HCHO mixing ratio within Planetary Boundary Layer (PBL) in Seoul, we converted Pandora HCHOVCDs to HCHO mixing ratio in the PBL using several meteorological input data from the Atmospheric InfraRed Sounder (AIRS). Seasonal HCHO mixing ratio in PBL converted from Pandora (OMI) HCHOVCDs are estimated to be 6.57 (5.17), 7.08 (6.68), 7.60 (4.70), and 5.00 (4.76) ppbv in spring, summer, autumn, and winter, respectively.Keywords: formaldehyde, OMI, Pandora, remote sensing
Procedia PDF Downloads 1475225 Analyzing the Impact of Board Diversity on Firm Performance: Case Study of the Nigerian Banking Sector
Authors: Data Collete Bob-Manuel
Abstract:
In light of global financial crisis in 2007-2008 various factors including board diversity, succession planning and board evaluation have been identified as essential ingredients in ensuring board effectiveness. The composition and structure of the board is of outmost importance in assessing a board’s ability and success in achieving its objectives. Following the corporate frauds and accounting scandals such as Enron, WorldCom, Parmalat, Oceanic Bank Nigeria and AfriBank Nigeria, there has been a notable amount of research about the effectiveness of the board of directors in the corporate governance of firms. The need to have an effective board cannot be over emphasized as it results in a more stable and thriving company. There has been an overarching need in the business world for a more diverse workforce and board of directors. Big corporations like Texaco, Ford Motors and DuPont have stated how diversity at every level of the workforce including the board of directors has been cited as a vital element for a company to succeed. Developed countries are also seeking for companies to have a more diverse board. For instance Norway has implemented a 60:40 board ratio to all companies. In West Africa, particularly Nigeria, the topic of diversity has received little attention as most studies conducted have focused on the gender aspect of diversity, which results found to have a negative impact on firm performance. This paper seeks to examine four variables of diversity; age, ethnicity, gender and skills to weigh the positive or negative impact the variables have on firm performance, based on evidence from the Nigerian Financial sector. Information used for this study will be gathered from financial statements and annual reports so as to enable the researcher to reflect on past years to know what is being done differently today. The findings of this study will help the researcher to develop a working definition for ethnicity with regards to the West African context where the issue of “tribe” is a sensitive topic.Keywords: Board of Directors, Board Diversity, Firm Performance, Nigeria
Procedia PDF Downloads 3775224 Dynamic Behavior of the Nanostructure of Load-Bearing Biological Materials
Authors: Mahan Qwamizadeh, Kun Zhou, Zuoqi Zhang, Yong Wei Zhang
Abstract:
Typical load-bearing biological materials like bone, mineralized tendon and shell, are biocomposites made from both organic (collagen) and inorganic (biomineral) materials. This amazing class of materials with intrinsic internally designed hierarchical structures show superior mechanical properties with regard to their weak components from which they are formed. Extensive investigations concentrating on static loading conditions have been done to study the biological materials failure. However, most of the damage and failure mechanisms in load-bearing biological materials will occur whenever their structures are exposed to dynamic loading conditions. The main question needed to be answered here is: What is the relation between the layout and architecture of the load-bearing biological materials and their dynamic behavior? In this work, a staggered model has been developed based on the structure of natural materials at nanoscale and Finite Element Analysis (FEA) has been used to study the dynamic behavior of the structure of load-bearing biological materials to answer why the staggered arrangement has been selected by nature to make the nanocomposite structure of most of the biological materials. The results showed that the staggered structures will efficiently attenuate the stress wave rather than the layered structure. Furthermore, such staggered architecture is effectively in charge of utilizing the capacity of the biostructure to resist both normal and shear loads. In this work, the geometrical parameters of the model like the thickness and aspect ratio of the mineral inclusions selected from the typical range of the experimentally observed feature sizes and layout dimensions of the biological materials such as bone and mineralized tendon. Furthermore, the numerical results validated with existing theoretical solutions. Findings of the present work emphasize on the significant effects of dynamic behavior on the natural evolution of load-bearing biological materials and can help scientists to design bioinspired materials in the laboratories.Keywords: load-bearing biological materials, nanostructure, staggered structure, stress wave decay
Procedia PDF Downloads 4475223 Study of Bored Pile Retaining Wall Using Physical Modeling
Authors: Amin Eslami, Jafar Bolouri Bazaz
Abstract:
Excavation and retaining walls are of challenging issues in civil engineering. In this study, the behavior of one the important type of supporting systems called Contiguous Bored Pile (CBP) retaining wall is investigated using a physical model. Besides, a comparison is made between two modes of free end piles(soft bed) and fixed end piles (stiff bed). Also a back calculation of effective length (the real free length of pile) is done by measuring lateral deflection of piles in different stages of excavation in both a forementioned cases. Based on observed results, for the fixed end mode, the effective length to free length ratio (Leff/L0) is equal to unity in initial stages of excavation and less than 1 in its final stages in a decreasing manner. While this ratio for free end mode, remains constant during all stages of excavation and is always less than unity.Keywords: contiguous bored pile wall, effective length, fixed end, free end, free length
Procedia PDF Downloads 3935222 Chi Square Confirmation of Autonomic Functions Percentile Norms of Indian Sportspersons Withdrawn from Competitive Games and Sports
Authors: Pawan Kumar, Dhananjoy Shaw, Manoj Kumar Rathi
Abstract:
Purpose of the study were to compare between (a) frequencies among the four quartiles of percentile norms of autonomic variables from power events and (b) frequencies among the four quartiles percentile norms of autonomic variables from aerobic events of Indian sportspersons withdrawn from competitive games and sports in regard to number of samples falling in each quartile. The study was conducted on 430 males of 30 to 35 years of age. Based on the nature of game/sports the retired sportspersons were classified into power events (throwers, judo players, wrestlers, short distance swimmers, cricket fast bowlers and power lifters) and aerobic events (long distance runners, long distance swimmers, water polo players). Date was collected using ECG polygraphs. Data were processed and extracted using frequency domain analysis and time domain analysis. Collected data were computed with frequency, percentage of each quartile and finally the frequencies were compared with the chi square analysis. The finding pertaining to norm reference comparison of frequencies among the four quartiles of Indian sportspersons withdrawn from competitive games and sports from (a) power events suggests that frequency distribution in four quartile namely Q1, Q2, Q3, and Q4 are significantly different at .05 level in regard to variables namely, SDNN, Total Power (Absolute Power), HF (Absolute Power), LF (Normalized Power), HF (Normalized Power), LF/HF ratio, deep breathing test, expiratory respiratory ratio, valsalva manoeuvre, hand grip test, cold pressor test and lying to standing test, whereas, insignificantly different at .05 level in regard to variables namely, SDSD, RMSSD, SDANN, NN50 Count, pNN50 Count, LF (Absolute Power) and 30: 15 Ratio (b) aerobic events suggests that frequency distribution in four quartile are significantly different at .05 level in regard to variables namely, SDNN, LF (Normalized Power), HF (Normalized Power), LF/HF ratio, deep breathing test, expiratory respiratory ratio, hand grip test, cold pressor test, lying to standing test and 30: 15 ratio, whereas, insignificantly different at .05 level in regard to variables namely, SDSD, RMSSD. SDANN, NN50 count, pNN50 count, Total Power (Absolute Power), LF(Absolute Power) HF(Absolute Power), and valsalva manoeuvre. The study concluded that comparison of frequencies among the four quartiles of Indian retired sportspersons from power events and aerobic events are different in four quartiles in regard to selected autonomic functions, hence the developed percentile norms are not homogenously distributed across the percentile scale; hence strengthen the percentage distribution towards normal distribution.Keywords: power, aerobic, absolute power, normalized power
Procedia PDF Downloads 3495221 Assessment of Power Formation in Gas Turbine Power Plants Using Different Inlet Air Cooling Systems
Authors: Nikhil V. Nayak
Abstract:
In this paper, the influence of air cooling intake on the gas turbine performance is presented. A comparison among different cooling systems, i.e., evaporative and cooling coil, is performed. A computer simulation model for the employed systems is developed in order to evaluate the performance of the studied gas turbine unit, at Marka Power Station, Amman, Bangalore. The performance characteristics are examined for a set of actual operational parameters including ambient temperature, relative humidity, turbine inlet temperature, pressure ratio, etc. The obtained results showed that the evaporative cooling system is capable of boosting the power and enhancing the efficiency of the studied gas turbine unit in a way much cheaper than cooling coil system due to its high power consumption required to run the vapor-compression refrigeration unit. Nevertheless, it provides full control on the temperature inlet conditions regardless of the relative humidity ratio.Keywords: power augmentation, temperature control, evaporative cooling, cooling coil, gas turbine
Procedia PDF Downloads 3795220 Simulation Study on Vehicle Drag Reduction by Surface Dimples
Authors: S. F. Wong, S. S. Dol
Abstract:
Automotive designers have been trying to use dimples to reduce drag in vehicles. In this work, a car model has been applied with dimple surface with a parameter called dimple ratio DR, the ratio between the depths of the half dimple over the print diameter of the dimple, has been introduced and numerically simulated via k-ε turbulence model to study the aerodynamics performance with the increasing depth of the dimples The Ahmed body car model with 25 degree slant angle is simulated with the DR of 0.05, 0.2, 0.3 0.4 and 0.5 at Reynolds number of 176387 based on the frontal area of the car model. The geometry of dimple changes the kinematics and dynamics of flow. Complex interaction between the turbulent fluctuating flow and the mean flow escalates the turbulence quantities. The maximum level of turbulent kinetic energy occurs at DR = 0.4. It can be concluded that the dimples have generated extra turbulence energy at the surface and as a result, the application of dimples manages to reduce the drag coefficient of the car model compared to the model with smooth surface.Keywords: aerodynamics, boundary layer, dimple, drag, kinetic energy, turbulence
Procedia PDF Downloads 3115219 Stream Channel Changes in Balingara River, Sulawesi Tengah
Authors: Muhardiyan Erawan, Zaenal Mutaqin
Abstract:
Balingara River is one of the rivers with the type Gravel-Bed in Indonesia. Gravel-Bed Rivers easily deformed in a relatively short time due to several variables, that are climate (rainfall), river discharge, topography, rock types, and land cover. To determine stream channel changes in Balingara River used Landsat 7 and 8 and analyzed planimetric or two dimensions. Parameters to determine changes in the stream channel are sinuosity ratio, Brice Index, the extent of erosion and deposition. Changes in stream channel associated with changes in land cover then analyze with a descriptive analysis of spatial and temporal. The location of a stream channel has a low gradient in the upstream, and middle watershed with the type of rock in the form of gravel is more easily changed than other locations. Changes in the area of erosion and deposition influence the land cover changes.Keywords: Brice Index, erosion, deposition, gravel-bed, land cover change, sinuosity ratio, stream channel change
Procedia PDF Downloads 3245218 Simulation of the Performance of the Reforming of Methane in a Primary Reformer
Authors: A. Alkattib, M. Boumaza
Abstract:
Steam reforming is industrially important as it is incorporated in several major chemical processes including the production of ammonia, methanol, hydrogen and ox alcohols. Due to the strongly endothermic nature of the process, a large amount of heat is supplied by fuel burning (commonly natural gas) in the furnace chamber. Reaction conversions, tube catalyst life, energy consumption and CO2 emission represent the principal factors affecting the performance of this unit and are directly influenced by the high operating temperatures and pressures. This study presents a simulation of the performance of the reforming of methane in a primary reformer, through a developed empirical relation which enables to investigate the effects of operating parameters such as the pressure, temperature, steam to carbon ratio on the production of hydrogen, as well as the fraction of non-converted methane. It appears from this analysis that the exit temperature Te, the operating pressure as well the steam to carbon ratio has an important effect on the reforming of methane.Keywords: reforming, methane, performance, hydrogen, parameters
Procedia PDF Downloads 2205217 DC-to-DC Converters for Low-Voltage High-Power Renewable Energy Systems
Authors: Abdar Ali, Rizwan Ullah, Zahid Ullah
Abstract:
This paper focuses on the study of DC-to-DC converters, which are suitable for low-voltage high-power applications. The output voltages generated by renewable energy sources such as photovoltaic arrays and fuel cell stacks are generally low and required to be increased to high voltage levels. Development of DC-to-DC converters, which provide high step-up voltage conversion ratios with high efficiencies and low voltage stresses is one of the main issues in the development of renewable energy systems. A procedure for three converters-conventional DC-to-DC converter, interleaved boost converter, and isolated flyback based converter, is illustrated for a given set of specifications. The selection among the converters for the given application is based on the voltage conversion ratio, efficiency, and voltage stresses.Keywords: flyback converter, interleaved boost, photovoltaic array, fuel cell, switch stress, voltage conversion ratio, renewable energy
Procedia PDF Downloads 5895216 Shielding Effectiveness of Rice Husk and CNT Composites in X-Band Frequency
Authors: Y. S. Lee, F. Malek, E. M. Cheng, W. W. Liu, F. H. Wee, M. N. Iqbal, Z. Liyana, B. S. Yew, F. S. Abdullah
Abstract:
This paper presents the electromagnetic interference (EMI) shielding effectiveness of rice husk and carbon nanotubes (RHCNTs) composites in the X-band region (8.2-12.4 GHz). The difference weight ratio of carbon nanotubes (CNTs) were mix with the rice husk. The rectangular wave guide technique was used to measure the complex permittivity of the RHCNTs composites materials. The complex permittivity is represented in terms of both the real and imaginary parts of permittivity in X-band frequency. The conductivity of RHCNTs shows increasing when the ratio of CNTs mixture increases. The composites materials were simulated using Computer Simulation Technology (CST) Microwave Studio simulation software. The shielding effectiveness of RHCNTs and pure rice husk was compared. The highest EMI SE of 30 dB is obtained for RHCNTs composites of 10 wt % CNTs with 10 mm thick.Keywords: EMI shielding effectiveness, carbon nanotube, composite materials wave guide, x-band
Procedia PDF Downloads 4015215 Exploratory Study to Obtain a Biolubricant Base from Transesterified Oils of Animal Fats (Tallow)
Authors: Carlos Alfredo Camargo Vila, Fredy Augusto Avellaneda Vargas, Debora Alcida Nabarlatz
Abstract:
Due to the current need to implement environmentally friendly technologies, the possibility of using renewable raw materials to produce bioproducts such as biofuels, or in this case, to produce biolubricant bases, from residual oils (tallow), originating has been studied of the bovine industry. Therefore, it is hypothesized that through the study and control of the operating variables involved in the reverse transesterification method, a biolubricant base with high performance is obtained on a laboratory scale using animal fats from the bovine industry as raw materials, as an alternative for material recovery and environmental benefit. To implement this process, esterification of the crude tallow oil must be carried out in the first instance, which allows the acidity index to be decreased ( > 1 mg KOH/g oil), this by means of an acid catalysis with sulfuric acid and methanol, molar ratio 7.5:1 methanol: tallow, 1.75% w/w catalyst at 60°C for 150 minutes. Once the conditioning has been completed, the biodiesel is continued to be obtained from the improved sebum, for which an experimental design for the transesterification method is implemented, thus evaluating the effects of the variables involved in the process such as the methanol molar ratio: improved sebum and catalyst percentage (KOH) over methyl ester content (% FAME). Finding that the highest percentage of FAME (92.5%) is given with a 7.5:1 methanol: improved tallow ratio and 0.75% catalyst at 60°C for 120 minutes. And although the% FAME of the biodiesel produced does not make it suitable for commercialization, it does ( > 90%) for its use as a raw material in obtaining biolubricant bases. Finally, once the biodiesel is obtained, an experimental design is carried out to obtain biolubricant bases using the reverse transesterification method, which allows the study of the effects of the biodiesel: TMP (Trimethylolpropane) molar ratio and the percentage of catalyst on viscosity and yield as response variables. As a result, a biolubricant base is obtained that meets the requirements of ISO VG (Classification for industrial lubricants according to ASTM D 2422) 32 (viscosity and viscosity index) for commercial lubricant bases, using a 4:1 biodiesel molar ratio: TMP and 0.51% catalyst at 120°C, at a pressure of 50 mbar for 180 minutes. It is necessary to highlight that the product obtained consists of two phases, a liquid and a solid one, being the first object of study, and leaving the classification and possible application of the second one incognito. Therefore, it is recommended to carry out studies of the greater depth that allows characterizing both phases, as well as improving the method of obtaining by optimizing the variables involved in the process and thus achieving superior results.Keywords: biolubricant base, bovine tallow, renewable resources, reverse transesterification
Procedia PDF Downloads 1125214 Groundwater Quality and Its Suitability for Agricultural Use in the Jeloula Basin, Tunisia
Authors: Intissar Farid
Abstract:
Groundwater quality assessment is crucial for sustainable water use, especially in semi-arid regions like the Jeloula basin in Tunisia, where groundwater is essential for domestic and agricultural needs. The present research aims to characterize the suitability of groundwater for irrigational purposes by considering various parameters: total salt concentration as measured by Electrical Conductivity EC, relative proportions of Na⁺ as expressed by %Na and SAR, Kelly’s ratio, Permeability Index, Magnesium hazard and Residual Sodium chloride. Chemical data indicate that the percent sodium (%Na) in the study area ranged from 26.3 to 45.3%. According to the Wilcox diagram, the quality classification of irrigation water suggests that analyzed groundwaters are suitable for irrigation purposes. The SAR values vary between 2.1 and 5. Most of the groundwater samples plot in the Richards’C3S1 water class and indicate little danger from sodium content to soil and plant growth. The Kelly’s ratio of the analyzed samples ranged from 0.3 to 0.8. These values indicate that the waters are fit for agricultural purposes. Magnesium hazard (MH) values range from 27.5 to 52.6, with an average of 38.9 in the analyzed waters. Hence, the Mg²⁺ content of the groundwater from the shallow aquifer cannot cause any problem to the soil permeability. Permeability index (PI) values computed for the area ranged from 33.6 to 52.7%. The above result, therefore, suggests that most of the water samples fall within class I of the Doneen chart and can be categorized as good irrigation water. The groundwaters collected from the Jeloula shallow aquifer were found to be within the safe limits and thus suitable for irrigation purposes.Keywords: Kelly's ratio, magnesium hazard, permeability index, residual sodium chloride
Procedia PDF Downloads 95213 Transient Electrical Resistivity and Elastic Wave Velocity of Sand-Cement-Inorganic Binder Mixture
Authors: Kiza Rusati Pacifique, Ki-il Song
Abstract:
The cement milk grout has been used for ground improvement. Due to the environmental issues related to cement, the reduction of cement usage is requesting. In this study, inorganic binder is introduced to reduce the use of cement contents for ground improvement. To evaluate transient electrical and mechanical properties of sand-cement-inorganic binder mixture, two non-destructive testing (NDT) methods, Electrical Resistivity (ER) and Free Free Resonant Column (FFRC) tests were adopted in addition to unconfined compressive strength test. Electrical resistivity, longitudinal wave velocity and damping ratio of sand-cement admixture samples improved with addition of inorganic binders were measured. Experimental tests were performed considering four different mixing ratios and three different cement contents depending on the curing time. Results show that mixing ratio and curing time have considerable effects on electrical and mechanical properties of mixture. Unconfined compressive strength (UCS) decreases as the cement content decreases. However, sufficient grout strength can be obtained with increase of content of inorganic binder. From the results, it is found that the inorganic binder can be used to enhance the mechanical properties of mixture and reduce the cement content. It is expected that data and trends proposed in this study can be used as reference in predicting grouting quality in the field.Keywords: damping ratio, electrical resistivity, ground improvement, inorganic binder, longitudinal wave velocity, unconfined compression strength
Procedia PDF Downloads 3375212 A High Step-Up DC-DC Converter for Renewable Energy System Applications
Authors: Sopida Vacharasukpo, Sudarat Khwan-On
Abstract:
This paper proposes a high step-up DC-DC converter topology for renewable energy system applications. The proposed converter employs only a single power switch instead of using several switches. Compared to the conventional DC-DC step-up converters the higher voltage gain with small output ripples can be achieved by using the proposed high step-up DC-DC converter topology. It can step up the low input voltage (20-50Vdc) generated from the photovoltaic modules to the high output voltage level approximately 600Vdc in order to supply the three-phase inverter fed the three-phase motor drive. In this paper, the operating principle of the proposed converter topology and its control strategy under the continuous conduction mode (CCM) are described. Finally, simulation results are shown to demonstrate the effectiveness of the proposed high step-up DC-DC converter with its control strategy to increase the voltage step-up conversion ratio.Keywords: DC-DC converter, high step-up ratio, renewable energy, single switch
Procedia PDF Downloads 11825211 Impact of Fluid Flow Patterns on Metastable Zone Width of Borax in Dual Radial Impeller Crystallizer at Different Impeller Spacings
Authors: A. Čelan, M. Ćosić, D. Rušić, N. Kuzmanić
Abstract:
Conducting crystallization in an agitated vessel requires a proper selection of mixing parameters that would result in a production of crystals of specific properties. In dual impeller systems, which are characterized by a more complex hydrodynamics due to the possible fluid flow interactions, revealing a clear link between mixing parameters and crystallization kinetics is still an open issue. The aim of this work is to establish this connection by investigating how fluid flow patterns, generated by two impellers mounted on the same shaft, reflect on metastable zone width of borax decahydrate, one of the most important parameters of the crystallization process. Investigation was carried out in a 15-dm3 bench scale batch cooling crystallizer with an aspect ratio (H/T) equal to 1.3. For this reason, two radial straight blade turbines (4-SBT) were used for agitation. Experiments were conducted at different impeller spacings at the state of complete suspension. During the process of an unseeded batch cooling crystallization, solution temperature and supersaturation were continuously monitored what enabled a determination of the metastable zone width. Hydrodynamic conditions in the vessel achieved at different impeller spacings investigated were analyzed in detail. This was done firstly by measuring the mixing time required to attain the desired level of homogeneity. Secondly, fluid flow patterns generated in a described dual impeller system were both photographed and simulated by VisiMix Turbulent software. Also, a comparison of these two visualization methods was performed. Experimentally obtained results showed that metastable zone width is definitely affected by the hydrodynamics in the crystallizer. This means that this crystallization parameter can be controlled not only by adjusting the saturation temperature or cooling rate, as is usually done, but also by choosing a suitable impeller spacing that will result in a formation of crystals of wanted size distribution.Keywords: dual impeller crystallizer, fluid flow pattern, metastable zone width, mixing time, radial impeller
Procedia PDF Downloads 1895210 An Alternative to Problem-Based Learning in a Post-Graduate Healthcare Professional Programme
Authors: Brogan Guest, Amy Donaldson-Perrott
Abstract:
The Master’s of Physician Associate Studies (MPAS) programme at St George’s, University of London (SGUL), is an intensive two-year course that trains students to become physician associates (PAs). PAs are generalized healthcare providers who work in primary and secondary care across the UK. PA programmes face the difficult task of preparing students to become safe medical providers in two short years. Our goal is to teach students to develop clinical reasoning early on in their studies and historically, this has been done predominantly though problem-based learning (PBL). We have had an increase concern about student engagement in PBL and difficulty recruiting facilitators to maintain the low student to facilitator ratio required in PBL. To address this issue, we created ‘Clinical Application of Anatomy and Physiology (CAAP)’. These peer-led, interactive, problem-based, small group sessions were designed to facilitate students’ clinical reasoning skills. The sessions were designed using the concept of Team-Based Learning (TBL). Students were divided into small groups and each completed a pre-session quiz consisting of difficult questions devised to assess students’ application of medical knowledge. The quiz was completed in small groups and they were not permitted access of external resources. After the quiz, students worked through a series of openended, clinical tasks using all available resources. They worked at their own pace and the session was peer-led, rather than facilitator-driven. For a group of 35 students, there were two facilitators who observed the sessions. The sessions utilised an infinite space whiteboard software. Each group member was encouraged to actively participate and work together to complete the 15-20 tasks. The session ran for 2 hours and concluded with a post-session quiz, identical to the pre-session quiz. We obtained subjective feedback from students on their experience with CAAP and evaluated the objective benefit of the sessions through the quiz results. Qualitative feedback from students was generally positive with students feeling the sessions increased engagement, clinical understanding, and confidence. They found the small group aspect beneficial and the technology easy to use and intuitive. They also liked the benefit of building a resource for their future revision, something unique to CAAP compared to PBL, which out students participate in weekly. Preliminary quiz results showed improvement from pre- and post- session; however, further statistical analysis will occur once all sessions are complete (final session to run December 2022) to determine significance. As a post-graduate healthcare professional programme, we have a strong focus on self-directed learning. Whilst PBL has been a mainstay in our curriculum since its inception, there are limitations and concerns about its future in view of student engagement and facilitator availability. Whilst CAAP is not TBL, it draws on the benefits of peer-led, small group work with pre- and post- team-based quizzes. The pilot of these sessions has shown that students are engaged by CAAP, and they can make significant progress in clinical reasoning in a short amount of time. This can be achieved with a high student to facilitator ratio.Keywords: problem based learning, team based learning, active learning, peer-to-peer teaching, engagement
Procedia PDF Downloads 775209 The Value of Study Abroad for Māori and Pasifika Learners: In Relation to the Tertiary Education Strategy in New Zealand
Authors: Easter Faasoo-Tuilagi
Abstract:
Study abroad has become a significant aspect of the tertiary system for New Zealand tertiary institutions and has been having a valuable contribution to student achievement and completion rate. The purpose of this doctoral study was to explore the significance and value of study abroad at an individual (learner), institutional (university), and national (government) level, with a focus on Māori and Pasifika learners. Previous research had conducted on the values and benefits of study abroad; however, there is a gap in knowledge on how study abroad can contribute to the educational experience of Māori and Pasifika students in tertiary studies in New Zealand. This study’s main focus aimed to explore the current participation and history of involvement of Māori and Pasifika students with study abroad using the University of Auckland and the University of Otago as case studies. It analysed the experiences of Māori and Pasifika students who were interested in study abroad or have returned from a study abroad. This research also explored how study abroad had become a significant aspect of the tertiary system in New Zealand, focusing on Tertiary Education Strategies. These questions were analysed using a range of methodologies, including a literature review to review how various institutions and nations, in particular New Zealand, were approaching study abroad, semi-structured interviews with Māori and Pasifika students on their experiences expressing interest in study abroad, and case studies of current/ returning Māori and Pasifika students who have had a study abroad experience. The anticipated results from this research will address several gaps in the existing literature and provide ways to better support Māori and Pasifika students who want to have a study abroad experience. This study will also inform education policy at an institutional and national level to boost the achievement of Māori and Pasifika students aligning with the Tertiary Education Strategy priorities.Keywords: study abroad, Māori and Pasifika learners, international education, tertiary education strategy
Procedia PDF Downloads 71