Search results for: important feature points

Authors: Shlomit Hon-Snir, Sharon Teitler-Regev, Anabel Lifszyc Friedlander

Abstract:

Tourism, one of the world's largest and fastest growing industries, exerts a major economic influence. The number of international tourists is growing every year, and the relative portion of independent (FIT) tourists is growing as well. The characteristics of independent tourists differ from those of tourists who travel in organized trips. The purpose of the research is to identify the factors that affect the individual tourist's expenses in Israel: total expenses, expenses per day, expenses per tourist, expenses per day per tourist, accommodation expenses, dining expenses and transportation expenses. Most of the research analyzed the total expenses using OLS regression. The determinants influencing expenses were divided into four groups: budget constraints, socio-demographic data, psychological characteristics and travel-related characteristics. Since the effect of each variable may change over different levels of total expenses the quantile regression (QR) theory will be applied. The current research will use data collected by the Israeli Ministry of Tourism in 2015 from individual independent tourists at the end of their visit to Israel. Preliminary results show that: At lower levels of expense, only income has a (positive) effect on total expenses, while at higher levels of expense, both income and length of stay have (positive) effects. -The effect of income on total expenses is higher for higher levels of expenses than for lower level of expenses. -The number of sites visited during the trip has a (negative) effect on tourist accommodation expenses only for tourists with a high level of total expenses. Due to the increasing share of independent tourism in Israel and around the world and due to the importance of tourism to Israel, it is very important to understand the factors that influence the expenses and behavior of independent tourists. Understanding the factors that affect independent tourists' expenses in Israel can help Israeli policymakers in their promotional efforts to attract tourism to Israel.

Keywords: independent tourist, quantile regression theory, tourism expenses, tourism

Procedia PDF Downloads 268

Authors: Sanela Slavkovic, Congor Nad, Spela Golubovic

Abstract:

Background: The diagnosis of multiple sclerosis (MS) is a major life challenge and has repercussions on all aspects of the daily functioning of those attained by it – personal activities, social participation, and quality of life. Regular follow-up of only the neurological status is not informative enough so that it could provide data on the sort of support and rehabilitation that is required. Objective: The aim of this study was to establish the current level of functioning of persons attained by MS and the factors that influence it. Methods: The study was conducted in Serbia, on a sample of 108 persons with relapse-remitting form of MS, aged 20 to 53 (mean 39.86 years; SD 8.20 years). All participants were fully ambulatory. Methods applied in the study include Expanded Disability Status Scale-EDSS and World Health Organization Disability Assessment Schedule, WHODAS 2.0 (36-item version, self-administered). Results: Participants were found to experience the most problems in the domains of Participation, Mobility, Life activities and Cognition. The least difficulties were found in the domain of Self-care. Symptom duration was the only control variable with a significant partial contribution to the prediction of the WHODAS scale score (β=0.30, p < 0.05). The total EDSS score correlated with the total WHODAS 2.0 score (r=0.34, p=0.00). Statistically significant differences in the domain of EDSS 0-5.5 were found within categories (0-1.5; 2-3.5; 4-5.5). The more pronounced a participant’s EDSS score was, although not indicative of large changes in the neurological status, the more apparent the changes in the functional domain, i.e. in all areas covered by WHODAS 2.0. Pyramidal (β=0.34, p < 0.05) and Bowel and bladder (β=0.24, p < 0.05) functional systems were found to have a significant partial contribution to the prediction of the WHODAS score. Conclusion: Measuring functioning and disability is important in the follow-up of persons suffering from MS in order to plan rehabilitation and define areas in which additional support is needed.

Keywords: disability, functionality, multiple sclerosis, rehabilitation

Procedia PDF Downloads 107

Authors: Omotoyosi Bilikies Ilori, Adekunle Saheed Ajisebiyawo

Abstract:

After the Second World War, there was an emergence of a new stage of capitalist globalization with its Neo-liberal ideology. There were global economic and political restructurings that affected third-world countries like Nigeria. Neo-liberalism is the driving force of globalization, which is the latest manifestation of imperialism that engenders endemic poverty in Nigeria. Poverty is severe and widespread in Nigeria. Poverty entails a situation where a person lives on less than one dollar per day and has no access to basic necessities of life. Poverty is inhuman and a breach of human rights. The Nigerian government initiated some strategies in the past to help in poverty reduction. Neo-liberalism manifested in the Third World, such as Nigeria, through the privatization of public enterprises, trade liberalization, and the rollback of the state investments in providing important social services. These main ideas of Neo-liberalism produced poverty in Nigeria and also encouraged the abandonment of the social contract between the government and the people. There is thus a gap in the provision of social services and subsidies for the masses, all of which Neo-liberal ideological positions contradict. This paper is a qualitative study which draws data from secondary sources. The theoretical framework is anchored on the market theory of capitalist globalization and public choice theory. The objectives of this study are to (i) examine the impacts of Neo-liberalism on poverty in Nigeria as a typical example of a Third World country and (ii) find out the effects of Neo-liberalism on the provision of social services and subsidies and employment. The findings from this study revealed that (i) the adoption of the Neo-liberal ideology by the Nigerian government has led to increased poverty and poor provision of social services and employment in Nigeria; and (ii) there is an increase in foreign debts which compounds poverty situation in Nigeria. This study makes the following recommendations: (i) Government should adopt strategies that are pro-poor to eradicate poverty; (ii) The Trade Unions and the masses should develop strategies to challenge Neo-liberalism and reject Neo-liberal ideology.

Keywords: neo-liberalism, poverty, employment, poverty reduction, structural adjustment programme

Procedia PDF Downloads 71

Authors: Gheyder Concha Bendezu, Rodrigo Lescano Loli, Aldo Bravo Lizano

Abstract:

In big urbanized cities of Latin America, motor vehicles have priority over non-motor vehicles and pedestrians. There is an important problem that affects people's health and quality of life; lack of inclusion towards pedestrians makes it difficult for them to move smoothly and safely since the city has been planned for the transit of motor vehicles. Faced with the new trend for sustainable and economical transport, the city is forced to develop infrastructure in order to incorporate pedestrians and users with non-motorized vehicles in the transport system. The present research aims to study the influence of non-motorized vehicles on an avenue, the optimization of a cycle using traffic lights based on simulation in Synchro software, to improve the flow of non-motor vehicles. The evaluation is of the microscopic type; for this reason, field data was collected, such as vehicular, pedestrian, and non-motor vehicle user demand. With the values of speed and travel time, it is represented in the current scenario that contains the existing problem. These data allow to create a microsimulation model in Vissim software, later to be calibrated and validated so that it has a behavior similar to reality. The results of this model are compared with the efficiency parameters of the proposed model; these parameters are the queue length, the travel speed, and mainly the travel times of the users at this intersection. The results reflect a reduction of 27% in travel time, that is, an improvement between the proposed model and the current one for this great avenue. The tail length of motor vehicles is also reduced by 12.5%, a considerable improvement. All this represents an improvement in the level of service and in the quality of life of users.

Keywords: bikeway, microsimulation, pedestrians, queue length, traffic light cycle, travel time

Procedia PDF Downloads 151

Authors: Mardiati Zain, Elihasridas, Yolani Utami, Bima Bagaskara, Muhammad Taufic

Abstract:

The purpose of this study is to formulated a ration that can increased concentration of bioactive compounds in the form of conjugated linoleic acid (CLA) and polyunsaturated fatty acids acid (PUFA) in milk to produce functional milk that is beneficial for health. It has been proven that forage-based feeds (grass and legumes) are able to increased the presence of polyunsaturated fatty acids and in particular conjugated linoleic acid CLA in milk. Presence of bioactive compounds in product fat of ruminant origin these have generated great interest because they are associated with their potential as anti carcinogenic, anti diabetogenic and stimulant of the immune response. PUFA and CLA and especially n-3 fatty acids, only 4% of the fatty acids present in milk. For that, efforts need to be made to change the fatty acid composition of milk to increase the nutritional value for consumers through increasing the concentration of PUFA and CLA This is very important in the midst of the covid pandemic 19 which is increasing, it is necessary to drink and food that can improve the system body immunity. . The study was conducted in vivo using a randomized block design with 4 treatments and 4 replications. This experiment used 16 heads of 40-55 kg lactating goats. Goat were fed a basal diet containing (dry matter basis) 60% native grass and 40% concentrate. The treatment was A. 60% native grass + 40% concentrate, B. 60% native grass + 30% concentrate + 10% I. zollengeriana C. 60% native grass + 20% concentrate + 20% I. zollengeriana, D, 60% native grass + 10% concentrate + 30% I. zollengeriana.The results showed that the using of I. zollengeriana until 30% in ration gave the same result with using concentrate of nutrien intake, and milk production but increased the CLA dan PUFA content in milk. The results of this study concluded that I. zollengeriana can increased the content of CLA and PUFA at the use of 75% substitute concentrate in the diet of lactating goats.

Keywords: Indigofera zollengeriana, lactation goat, milk production, CLA, PUFA

Procedia PDF Downloads 232

Authors: Madhura Bandyopadhyay

Abstract:

Teaching writing within multicultural and multiethnic communities poses many unique challenges not the least of which is that of intercultural communication. When the writing is in English, pedagogical imperatives often encounter the universalizing tendencies of standardization of both language use and structural parameters which are often at odds with maintaining local practices which preserve cultural pluralism. English often becomes the contact zone within which individual identities of students play out against the standardization imperatives of the larger world. Writing classes can serve as places which become instruments of assimilation of ethnic minorities to a larger globalizing or nationalistic agenda. Hence, for those outside of the standard practices of writing English, adaptability towards a mastery of those practices valued as standard become the focus of teaching taking away from diversity of local English use and other modes of critical thinking. In a very multicultural and multiethnic context such as the US or Singapore, these dynamics become very important. This paper will argue that multiethnic writing classrooms can greatly benefit from taking up a cultural studies approach whereby the students’ lived environments and experiences are analyzed as cultural texts to produce writing. Such an approach eliminates limitations of using both literary texts as foci of discussion as in traditional approaches to teaching writing and the current trend in teaching composition without using texts at all. By bringing in students’ lived experiences into the classroom and analyzing them as cultural compositions stressing the ability to communicate across cultures, cultural competency is valued rather than adaptability while privileging pluralistic experiences as valuable even as universal shared experience are found. Specifically, while teaching writing in English in a multicultural classroom, a cultural studies approach makes both teacher and student aware of the diversity of the English language as it exists in our global context in the students’ experience while making space for diversity in critical thinking, structure and organization of writing effective in an intercultural context.

Keywords: English, multicultural, teaching, writing

Procedia PDF Downloads 496

Authors: Yu-Sheng Lin, Sheng-Teng Huang

Abstract:

In recent years, the issue of corporate social responsibility has become an enthusiastic discussion and hottest issue around the world. To make the enterprises be sustainable management and sustainable development, more and more enterprises realize that fulfill its corporate social responsibility is the good choice. It is an essential, important issue that the leader needs know how to lead the staff in balance benefit, also emphasize on economic, social and environmental aspects to impact the company, then enhance the consensus. The leader needs to improve cohesion of personnel, and implement the corporate social responsibility in staff behavior, in order to show a performance in the effort of corporate social responsibility of enterprises. The previous literature mostly is committed to comparison of corporate social responsibility in the industry and service industry, regarding to literature of shipping companies were relatively rare. This paper aims to take the domestic and foreign shipping companies of corporate social responsibility reports as the data analysis, and refer to the international convention (GRI) such as association and organization of CSR standard values. Overall comparison with shipping companies of CSR reports, annual reports and other public information, and taking Taiwan shipping companies as the target, respectively, with the international conventions and the world's top ten leading shipping companies to do the comparison and analysis. Shipping companies in Taiwan are bound to the standard that set by the international convention for the first goal diligently and following step is contend with the world's top ten leading shipping companies. There are 3 ~ 5 experts to be involved in interview after the result is completed. They will indicate the superiority and inferiority then provide the opinion, recommendation in the needed action. Through this study, we can explore the importance of corporate social responsibility report for shipping companies, and also provide the clear orientation to external providers to improve corporate social responsibility. In addition, it can provide the academic research and business experts as a reference; finally, serving shipping companies to complete another contribution.

Keywords: Corporate social responsibility (CSR), CSR reports, statistical methods, expert interview method

Procedia PDF Downloads 280

Authors: Akanji Kayode Ayanwusi., Akanji Elizabeth Nike, Bidmos Fuad Adetunji, Oladapo Olufemi Stephen

Abstract:

This experiment was conducted in Igboora, southwest Nigeria during the year 2022 planting season to determine the bio-efficacy of plant extracts (Jatropha curcas and Petiveria alliacea) and synthetic (Cypermethrin) insecticides against the insect pest of cowpea (Vigna unguiculata L.) and to determine its effect on the growth and yield of cowpea in the study area. Cowpea is one of the most important food and forage legumes in the semi-arid tropics. It is grown in 45 countries worldwide, including parts of Africa, Asia, Southern Europe, the Southern United States, and Central and South America. Cowpea production is considered too risky an enterprise by many growers because of its numerous pest problems. The treatments for the experiment consisted of two aqueous plant extracts (J.curcas and P. alliacea) at 50 /0 w/v and Cypermethrin 400 EC replicated three times including control in a randomized complete block design. Each plot measured 2.0 m by 2.0 m with 1.0 m inter-spaced per adjacent plot. The results from the study showed that different insect pests attack cowpea at different stages of growth. The insects observed were Bemisa tabaci, Callosobruchus maculatus, Megalurothrips sjostedti, and Maruca vitrata. High yields were obtained from plots treated with P. alliacea and synthetic insecticide (cypermethrin). J. curcas also produced optimum yield but lower than P. alliacea also P. alliacea treated plots had the least damaged pods while the untreated plots had the highest damaged pods, the plants extracts exhibited high insecticidal activities in this study, therefore P. alliacea leaves formulated as an insecticide is recommended for the control of insect pests of cowpea in the study area.

Keywords: plant extracts, yield, cypermethrin., cowpea

Procedia PDF Downloads 71

Authors: Bahram Soltani, Louai Ghazieh

Abstract:

The responsibility has a big importance further to the financial crisis and the various pressures, which companies face their duties. The main objective of this study is to explain the variation of mechanisms of the responsibility of the manager in the company among the advanced capitalist economies. Then we study the impact of these mechanisms on the performance and the value creation in European companies. To reach our goal, we established a final sample composed on average of 284 French, British and German companies quoted in stock exchanges with 2272 annual reports examined during the period from 2005 to 2012. We examined at first the link of causalities between the determining-mechanisms bound to the company such as the characteristics of the board of directors, the composition of the shareholding and the ethics of the company on one side and the profitability of the company on the other side. The results show that the smooth running of the board of directors and its specialist committees are very important determinants of the responsibility of the managers who impact positively the performance and the value creation in the company. Furthermore, our results confirm that the presence of a solid ethical environment within the company will be effective to increase the probability that the managers realize ethical choices in the organizational decision-making. At the second time, we studied the impact of the determining mechanisms bound to the function and to the profile of manager to know its relational links, his remuneration, his training, his age and his experiences about the performance and the value creation in the company. Our results highlight the existence of a negative relation between the relational links of the manager, his very high remuneration and the general profitability of the company. This study is a contribution to the literature on the determining mechanisms of company director's responsibility (Accountability). It establishes an empirical and comparative analysis between three influential countries of Europe, to know France, the United Kingdom and Germany.

Keywords: leaders, company’s performance, accountability mechanisms, corporate governance, value creation of firm, financial crisis

Procedia PDF Downloads 369

Authors: Kgopa Bontle, Tholen Sodi

Abstract:

Climate change poses a major threat to the well-being of both people and the environment, with subsistence farmers most affected as they rely on local supply systems that are sensitive to climate variation. This study documented psychological resilience factors associated with climate change adaptations by subsistence farmers in Maruleng Municipality, Limpopo Province. A qualitative study was conducted to examine the notions of climate change by subsistence farmers, the psychological resilience factors, the strategies to cope with climate change, adaptation methods, and the development of subsistence farmers’ psychological resilience factors model. Data were collected through direct interactions with participants using a grounded theory research design. An open-ended interview was used to collect data with a sample of 15 participants selected through theoretical sampling in Maruleng Municipality. The participants were both Sepedi and Xitsonga speaking from 2 villages, mostly unemployed, pensioners and dependent on social grants. The study included both males and females who were predominately the elderly. The research findings indicate that farmers have limited knowledge of what climate change is and what causes it. Furthermore, the research reflects that although their responses were non-scientific but sensible enough to know what they were dealing with. They mentioned extreme weather, which includes hot days and less rainfall and changes in seasons, as some of the impacts brought by climate change. The results also indicated that participants have learned to adapt through several adaptation strategies, including mulching, changes in irrigation time slots and being innovative. The resilience factors that emerged from the study were a passion for farming, hope, enthusiasm, courage, acceptance/tolerance, livelihood and belief systems. Looking at the socio-economic factors of the current study setting argumentation leads to the conclusion that it is important that government should assist the subsistence farmers as it was observed from the participants that they felt neglected by the government and policymakers as they are small scale farmers and are not included like commercial farmers.

Keywords: climate change, psychological resilience factors, human adaptation, subsistence farmers

Procedia PDF Downloads 112

Authors: Shuofen Hsu, Ya-Yi Chao, Chao-Wei Li

Abstract:

This paper investigates the relationship between voluntary audit (hereafter, VA) of semi-annual consolidated financial statements decision and accounting conservatism. In general, there are four kinds of auditors' assurance services, which include audit, review, agreed-upon procedure and compliance engagements base on degree of assurance. The VA work by auditors may not only have the higher audit quality but an important signal of more reliable information than the review work. In Taiwan, The listed companies must prepare the semi-annual consolidated financial statements and with auditors' review before 2012, but some of the listed companies choose the assurance work from review to audit voluntarily. Due to the adoption of International Financial Reporting Standards, the listed companies were required to prepare the second quarterly consolidated financial statements which should be reviewed by auditors since 2013. This rule will change some of the assurance work from audit to review by auditors, and the information asymmetry maybe increased. To control the selection bias, we use two-stage model to test the relationship between VA decision and accounting conservatism. Our empirical results indicate that the VA decision and accounting conservatism have a significant positive relationship in firms with family-controlled. That is, firms with family-controlled are more likely to do VA and to prepare more conservative consolidated financial statements to reduce the information asymmetry, meaning that there is a complementary effect between VA and accounting conservatism for firms with more information asymmetry. But on the contrary, we find that the VA decision and accounting conservatism have a significant negative relationship in firms with professional managers-controlled, meaning that there is a substitution effect between VA and accounting conservatism for firms with less information asymmetry. Finally, the accounting conservatism of consolidated financial statements decrease after the adoption of IFRSs (International Financial Reporting Standards) in Taiwan. It means that the disclosure and transparency of consolidated financial statements had be improved.

Keywords: voluntary audit, accounting conservatism, audit quality, information asymmetry

Procedia PDF Downloads 217

Authors: Vincent Murray

Abstract:

The glycopeptide bleomycin is used in the treatment of testicular cancer, Hodgkin's lymphoma, and squamous cell carcinoma. Bleomycin damages and cleaves DNA in human cells, and this is considered to be the main mode of action for bleomycin's anti-tumor activity. In particular, double-strand breaks are thought to be the main mechanism for the cellular toxicity of bleomycin. Using Illumina next-generation DNA sequencing techniques, the genome-wide sequence specificity of bleomycin-induced double-strand breaks was determined in human cells. The degree of bleomycin cleavage was also assessed at the transcription start sites (TSSs) of actively transcribed genes and compared with non-transcribed genes. It was observed that bleomycin preferentially cleaved at the TSSs of actively transcribed human genes. There was a correlation between the degree of this enhanced cleavage at TSSs and the level of transcriptional activity. Bleomycin cleavage is also affected by chromatin structure and at TSSs, the peaks of bleomycin cleavage were approximately 200 bp apart. This indicated that bleomycin was able to detect phased nucleosomes at the TSSs of actively transcribed human genes. The genome-wide cleavage pattern of the bleomycin analogues 6′-deoxy-BLM Z and zorbamycin was also investigated in human cells. As found for bleomycin, these bleomycin analogues also preferentially cleaved at the TSSs of actively transcribed human genes. The cytotoxicity (IC₅₀ values) of these bleomycin analogues was determined. It was found that the degree of enhanced cleavage at TSSs was inversely correlated with the IC₅₀ values of the bleomycin analogues. This suggested that the level of cleavage at the TSSs of actively transcribed human genes was important for the cytotoxicity of bleomycin and analogues. Hence this study provided a deeper understanding of the cellular processes involved in the cancer chemotherapeutic activity of bleomycin.

Keywords: anti-tumour activity, bleomycin analogues, chromatin structure, genome-wide study, Illumina DNA sequencing

Procedia PDF Downloads 109

Authors: Jotham Mazhura

Abstract:

Floriculture production is an ideal project for sustainable horticultural production in Masvingo city.Gender links in collaboration with the embasy of Sweedenare supporting the floriculture project with the aim of improving residents livelihoods in the city.World trade in floriculture such as cut flowers,live ornamental plants and foliage continue to increase and there are recognised markets opportunities across the globe.Some specific opportunitiesin an interview discussion by the consultant appointed by gender links and embasy of Sweeden highlightedsome constraints and opportunities in the project of floriculture in Masvingo city.Based on the outcome of the scoping studies this research project developed and evaluated strategies for enhancing floriculture production in Masvingo city. A survey was therefore carried out by the researcher among the existing florists farmers in the city to determine strategies to be employed to improve floriculture production.The survey was conducted to twenty florists in the city.The sample was taken by using purposive sampling which is a sampling technique based on the certain considerations, hence there were some basic creteria in selecting samples. A questionnaire in this aspect was administered to the 20 florists to determine the essential strategies to be employed to enhance floriculture production.Each respondent was given data for the business strategies and asked to rank those strategies from the most to the least important.From the research findings the following were revealed out by the respondents that is capturing marketshare,establishment of of ownership of the project,the project manager to be innovative,the business should gain competitive strategic through generic strategies market development strategy and product development strategy. Based on the observation and structured interview with respondents the average of floriculture owners had similar strategies implemented on their business.The research proved that floriculture farmers use various strategies to keep their businesses running and succeding in achieving set goals.Therefore the ressearche who happens to be the project focal person became certain that it is edeal to emply a variety of of strategies to improve floriculture oproduction

Keywords: florist, floriculture, strategy, livelihoods

Procedia PDF Downloads 66

Authors: Laura Sour

Abstract:

Government accounting is an essential instrument of transparency and accountability in public administration, which allows connecting internal management with the implementation of policies and their evaluation by third parties through the construction of indicators on the cost of government. Several countries have adopted the International Public Sector Accounting Standards (IPSAS) as part of their modernization strategy. This document will evaluate the quantity and harmonization of the financial information published in the financial statements of 12 Latin American countries based on what is established in IPSAS 1, 2 and 17. For this, seven types of financial statements are analyzed. published during the period from 2015 to 2019. Based on this information, it will be possible to describe the evolution in the government financial publication to carry out a detailed analysis of the items that have been most transparent in these countries. Finally, the level of harmonization of the financial statements will be studied using the Herfindahl-Hirschman index (IHH) to determine the degree of comparability of the information. To date, the results indicate that the public sector has increased the quantity and harmonization of the financial information published during the study period, but in a heterogeneous way: From the data collected, it has been found that the financial statement published with greater frequency and quantity is the Income Statement (classification of expenses by nature). On the other hand, the most complete reports were published by Costa Rica (2017 to 2019) and Mexico (2016 to 2018), periods during which these countries complied with 92.9 percent of the items analyzed. Although 2017 and 2018 are the years in which the most financial statements were reported, it is important to mention that Mexico is the country that has published the most financial information throughout the entire study period. The use of the IHH is expected to provide accurate information on the quality with which countries have adopted IPSAS within their government accounting systems to promote transparency and accountability in the continent.

Keywords: accounting and auditing, government policy and regulation, harmonization, public sector accounting and audits IPSAS

Procedia PDF Downloads 80

Authors: Mahsa Shafaei Bajestani, Mahmoud Yazdani, Aliakbar Golshani

Abstract:

Artificial lightweight aggregates have a wide range of applications in industry and engineering. Nowadays, the usage of this material in geotechnical activities, especially as backfill in retaining walls has been growing due to the specific characteristics which make it a competent alternative to the conventional geotechnical materials. In practice, a material with lower weight but higher shear strength parameters would be ideal as backfill behind retaining walls because of the important roles that these parameters play in decreasing the overall active lateral earth pressure. In this study, two types of Light Expanded Clay Aggregates (LECA) produced in the Leca factory are investigated. LECA is made in a rotary kiln by heating natural clay at different temperatures up to 1200 °C making quasi-spherical aggregates with different sizes ranged from 0 to 25 mm. The loose bulk density of these aggregates is between 300 and 700 kN/m³. The purpose of this research is to determine the stress-strain behavior, shear strength parameters, and the energy absorption of LECA materials. Direct shear tests were conducted at five normal stresses of 25, 50, 75, 100, and 200 kPa. In addition, conventional triaxial compression tests were operated at confining pressures of 50, 100, and 200 kPa to examine stress-strain behavior. The experimental results show a high internal angle of friction and even a considerable amount of nominal cohesion despite the granular structure of LECA. These desirable properties along with the intrinsic low density of these aggregates make LECA as a very proper material in geotechnical applications. Furthermore, the results demonstrate that lightweight aggregates may have high energy absorption that is excellent alternative material in seismic isolations.

Keywords: expanded clay, direct shear test, triaxial test, shear properties, energy absorption

Procedia PDF Downloads 150

Authors: A. Kumar, D. Himanshu, Ak Vaish, K. Usman , A. Singh, R. Misra, V. Atam, S. P. Verma, S. Singhal

Abstract:

Introduction: Resistant and uncontrolled hypertension offer great challenge, in terms of higher risk of morbidity, mortality and not the least, difficulty in diagnosis and management. Our study tries to identify the importance of two crucial aspects of hypertension management, i.e. drug compliance and optimum dosing and also the effect of spironolactone on blood pressure in cases of resistant hypertension. Methodology: A prospective study was carried out among patients, who were referred as case of resistant hypertension to Hypertension Clinic at Gandhi memorial and associated hospital, Lucknow, India from August, 2013 to July 2014. A total of 122 Subjects having uncontrolled BP with ≥3 antihypertensives were selected. After ruling out secondary resistance and with appropriate lifestyle modifications, effect of adherence and optimum doses was seen with monitoring of BP. Only those having blood pressure still uncontrolled were true resistant. These patients were given spironolactone to see its effect on BP over next 12 weeks. Results: Mean baseline BP of all (n=122) patients was 150.4±7.2 mmHg systolic and 92.1±5.7 mmHg diastolic. After promoting adherence to the regimen, there was reduction of 4.20±3.65 mmHg systolic and 2.08±4.74 mmHg Diastolic blood pressure, with 26 patients achieving target blood pressure goal. Further reduction of 6.66±5.99 mmHg in systolic and 2.59±3.67 mmHg in diastolic BP was observed after optimizing the drug doses with another 66 patients achieving target blood pressure goal. Only 30 patients were true resistant hypertensive and prescribed spironolactone. Over 12 weeks, mean reduction of 20.62±3.65 mmHg in systolic and 10.08 ± 6.46 mmHg in diastolic BP was observed. Out of these 30, BP was controlled in 24 patients. Side effects observed were hyperkalemia in 2 patients and breast tenderness in 2 patients. Conclusion: Improper adherence and suboptimal regimen appear to be the important reasons for uncontrolled hypertension. By virtue of maintaining proper adherence to an optimum regimen, target BP goal can be reached in many without adding much to the regimen. Spironolactone is effective in patients with resistant hypertension, in terms of blood pressure reduction with minimal side effects.

Keywords: resistant, hypertension, spironolactone, blood pressure

Procedia PDF Downloads 267

Authors: A. N. Ghafar, O. A. Chaudhari, W. Oettel, P. Fontana

Abstract:

This study is a part of the EU project GEOCOND-Advanced materials and processes to improve performance and cost-efficiency of shallow geothermal systems and underground thermal storage. In heat exchange boreholes, to improve the heat transfer between the pipes and the surrounding ground, the space between the pipes and the borehole wall is normally filled with geothermal grout. Traditionally, bentonite has been a crucial component in most commercially available geothermal grouts to assure the required stability and impermeability. The investigations conducted in the early stage of this project during the benchmarking tests on some commercial grouts showed considerable sensitivity of the rheological properties of the tested grouts to the mixing parameters, i.e., mixing time and velocity. Further studies on this matter showed that bentonite, which has been one of the important constituents in most grout mixes, was probably responsible for such behavior. Apparently, proper amount of shear should be applied during the mixing process to sufficiently activate the bentonite. The higher the amount of applied shear the more the activation of bentonite, resulting in change in the grout rheology. This explains why, occasionally in the field applications, the flow properties of the commercially available geothermal grouts using different mixing conditions (mixer type, mixing time, mixing velocity) are completely different than expected. A series of tests were conducted on the grout mixes, with and without bentonite, using different mixing protocols. The aim was to eliminate/reduce the sensitivity of the rheological properties of the geothermal grouts to the mixing parameters by replacing bentonite with polymeric (non-clay) stabilizers. The results showed that by replacing bentonite with a proper polymeric stabilizer, the sensitivity of the grout mix on mixing time and velocity was to a great extent diminished. This can be considered as an alternative for the developers/producers of geothermal grouts to provide enhanced materials with less uncertainty in obtained results in the field applications.

Keywords: flow properties, geothermal grout, mixing time, mixing velocity, rheological properties

Procedia PDF Downloads 115

Authors: Nawt Almutairi, Ramzi El-Haddadeh

Abstract:

With the extensive increase in the number of online shops, loyalty becomes the most purpose for e-retailers by which they can maintain their exit customers and regular income instead of spending large deal of money to target new segmentation. To obtain customers’ loyalty e-marketers should firstly satisfy customers by providing a high quality of services that could fulfil their demand. They have to satisfy them to trust the web-site then increase their intention to re-visit it. This study intends to investigate to what extend the elements of e-service quality presented in the literature affect customers’ satisfaction and how these influences contribute to customers’ trust and loyalty. Three dimensions of service quality are estimated. The first element is web-site interactivity, which is perceived the quality of interactive support and the accessible communications-tool. The second aspect is security/privacy, which is perceived the quality of controlling security and privacy while transaction over the web-site. The third element is web-design that perceived a pleasant user interface with visual appealing. These elements present positive effects on shoppers’ satisfaction. Thus, To examine the proposed constructs of this research, some measurements scale-items adapted from similar prior studies. Survey data collected online from Saudi customers (n=106) were utilized to test the research hypotheses. After that, the hypotheses were analyzed by using a variety of regression tools. The analytical results of this study propose that perceived quality of interactivity and security/privacy affects customers’ satisfaction. As well as trust seems to be a substantial construct that highly affects loyalty in online shopping. This study provides a developed model to obtain a simple understanding of the series of customers’ loyalty in online shopping. One construct presenting in the research model is web-design appears to be not important antecedent of satisfaction (the path to loyalty) in online shopping.

Keywords: e-service, satisfaction, trust, loyalty

Procedia PDF Downloads 245

Authors: Himanshu Lal, Bipasha Ghosh, Arun Srivastava

Abstract:

A pilot study of indoor air quality in terms of bioaerosol (fungus and bacteria) and few selective microbial volatile organic compounds (MVOCs) was carried out in different indoor sections of a library for two seasons, namely monsoon and post monsoon. Bioaerosol sampling was carried out using Anderson six stage viable sampler at a flow rate of 28.3 L/min while MVOCs were collected on activated charcoal tubes ORBOTM 90 Carboxen 564.Collected MVOCs were desorbed using carbon disulphide (CS2) and analysed by GC-FID. Microscopic identification for fungus was only carried out. Surface dust was collected by sterilised buds and cultured to identify fungal contaminants. Unlike bacterial size distribution, fungal bioaerosol concentration was found to be highest in the fourth stage in different sections of the library. In post monsoon season both fungal bioaerosol (710 to 3292cfu/m3) and bacterial bioaerosol (298 to 1475cfu/m3) were fund at much greater concentration than in monsoon. In monsoon season unlike post monsoon, I/O ratio for both the bioaerosol fractions was more than one. Rain washout could be the reason of lower outdoor concentration in monsoon season. On the contrary most of the MVOCs namely 1-hexene, 1-pentanol and 1-octen-3-ol were found in the monsoon season instead of post monsoon season with the highest being 1-hexene with 7.09µg/m3 concentration. Among the six identified fungal bioaerosol Aspergillus, Cladosporium and Penicillium were found in maximum concentration while Aspergillus niger, Curvuleria lunata, Cladosporium cladosporioides and Penicillium sp., was indentified in surface dust samples. According to regression analysis apart from environmental factors other factors also played an important role. Thus apart from outdoor infiltration and human sources, accumulated surface dust mostly on organic materials like books, wooden furniture and racks can be attributed to being one of the major sources of both fungal bioaerosols as well as MVOCs found in the library.

Keywords: bacteria, Fungi, indoor air, MVOCs

Procedia PDF Downloads 303

Authors: Mehrak Zargaryaeghoubi, Masood Hajali

Abstract:

Drilled shafts are the most popular of deep foundations, because they have the capability that one single shaft can easily carry the entire load of a large column from a bridge or tall building. Drilled shaft may be an economical alternative to pile foundations because a pile cap is not needed, which not only reduces that expense, but also provides a rough surface in the border of soil and concrete to carry a more axial load. Due to the larger construction sizes of drilled shafts, they have an excellent axial load carrying capacity. Part of the axial load carrying capacity of the drilled shaft is resisted by the soil below the tip of the shaft which is tip resistance and the other part is resisted by the friction developed around the drilled shaft which is side resistance. The condition at the bottom of the excavation can affect the end bearing capacity of the drilled shaft. Also, type of the soil and size of the drilled shaft can affect the frictional resistance. The main loads applied on the drilled shafts are axial compressive loads. It is important to know how many percent of the maximum applied load will be shed inside friction and how much will be transferred to the base. The axial capacity of the drilled shaft foundation is influenced by the size of the drilled shaft, and soil characteristics. In this study, the effect of the size and soil characteristic will be investigated on the contribution of side resistance and end-bearing capacity. Also, the study presents a three-dimensional finite element modeling of a drilled shaft subjected to axial load using ANSYS. The top displacement and settlement of the drilled shaft are verified with analytical results. The soil profile is considered as Table 1 and for a drilled shaft with 7 ft diameter and 95 ft length the stresses in z-direction are calculated through the length of the shaft. From the stresses in z-direction through the length of the shaft the side resistance can be calculated and with the z-direction stress at the tip, the tip resistance can be calculated. The result of the side and tip resistance for this drilled shaft are compared with the analytical results.

Keywords: Drilled Shaft Foundation, size and soil characteristic, axial load capacity, Finite Element

Procedia PDF Downloads 371

Authors: Ayman M. Mansour, Bilal Hawashin, Hesham Alsalem

Abstract:

Faster delivery of laboratory test results is one of the most noticeable signs of good laboratory service and is often used as a key performance indicator of laboratory performance. Despite the availability of technology, the delivery time of clinical laboratory test results continues to be a cause of customer dissatisfaction which makes patients feel frustrated and they became careless to get their laboratory test results. The Medical Clinical Laboratory test results are highly sensitive and could harm patients especially with the severe case if they deliver in wrong time. Such results affect the treatment done by physicians if arrived at correct time efforts should, therefore, be made to ensure faster delivery of lab test results by utilizing new trusted, Robust and fast system. In this paper, we proposed a distributed Multi-Agent System to enhance and faster the process of laboratory test results delivery using SMS. The developed system relies on SMS messages because of the wide availability of GSM network comparing to the other network. The software provides the capability of knowledge sharing between different units and different laboratory medical centers. The system was built using java programming. To implement the proposed system we had many possible techniques. One of these is to use the peer-to-peer (P2P) model, where all the peers are treated equally and the service is distributed among all the peers of the network. However, for the pure P2P model, it is difficult to maintain the coherence of the network, discover new peers and ensure security. Also, security is a quite important issue since each node is allowed to join the network without any control mechanism. We thus take the hybrid P2P model, a model between the Client/Server model and the pure P2P model using GSM technology through SMS messages. This model satisfies our need. A GUI has been developed to provide the laboratory staff with the simple and easy way to interact with the system. This system provides quick response rate and the decision is faster than the manual methods. This will save patients life.

Keywords: multi-agent system, delivery process, GSM technology, clinical laboratory results

Procedia PDF Downloads 241

Authors: Jakia Rajoana

Abstract:

The aim of this paper is to examine the role of women entrepreneurs in bringing about sustainable rural tourism (SRT) development in Sundarbans area of Bangladesh. Theoretically, it draws upon empowerment and entrepreneurial marketing concepts. Women entrepreneurship development and lack of empowered women as role models is an important issue for developing economies in South Asia. Despite the substantial role women play in rural economy of Sundarbans, their contribution remains overlooked as enterprises led by them are run on an informal basis and their business acumen is not taken seriously both by their families and society at large. Studies on SRT fail to engage in sufficient depth with the term applied in this paper as ‘invisible women on the margins’ who run their enterprises with no formal training or societal/familial support. Moreover, the link between their (non) tourism enterprise and their empowerment remains under-theorized. Thus empirically, this research seeks to fill a significant gap by focusing on a considerably under-researched Sundarbans region. Methodologically, this study follows a qualitative research design using visual ethnographic approach. Participant observation, semi-structured interviews, and documentation are the primary data collection instruments in three coastal communities – Munshigonj, Burigoalini and Gabura – in the Sundarbans area. By focusing on the narratives of these under-investigated women, this work aims to provide in-depth and nuanced insights into salient issues on marginal communities experience from rural women’s perspectives. Initial findings illustrate that the Sundarbans women have low income due to no or little education. In addition, socio-cultural and religious factors also restrict the scope of their extensive contribution to workplace. In addition, physical and social violence which is a common occurrence for these women inhibits their agency and contributes to their disempowerment.

Keywords: gender, empowerment, entrepreneurial marketing, sustainable rural tourism, Sundarbans

Procedia PDF Downloads 279

Authors: Giorgi Bregadze

Abstract:

Tourism is the most viable and sustainable economic development option for Georgia and one of the main sources of foreign exchange earnings. Events are considered as one of the most effective ways to attract foreign visitors to the country, and, recently, the government of Georgia has begun investing in this sector very actively. This article stresses the necessity of research based economic policy in the tourism sector. In this regard, it is of paramount importance to measure the economic effects of the events which are subsidized by taxpayers’ money. The economic effect of events can be analyzed from two perspectives; financial perspective of the government and perspective of economic effects of the tourism administration. The article emphasizes more realistic and all-inclusive focus of the economic effect analysis of the tourism administration as it concentrates on the income of residents and local businesses, part of which generate tax revenues for the government. The public would like to know what the economic returns to investment are. In this article, the methodology used to describe the economic effects of UEFA Super Cup held in Tbilisi, will help to answer this question. Methodology is based on three main principles and covers three stages. Using the suggested methodology article estimates the direct economic effect of UEFA Super cup on Georgian economy. Although the attempt to make an economic effect analysis of the event was successful in Georgia, some obstacles and insufficiencies were identified during the survey. The article offers several recommendations that will help to refine methodology and improve the accuracy of the data. Furthermore, it is very important to receive the correct standard of measurement of events in Georgia. In this caseü non-ethical acts of measurement which are widely utilized by different research companies will not trigger others to show overestimated effects. It is worth mentioning that to author’s best knowledge, this is the first attempt to measure the economic effect of an event held in Georgia.

Keywords: biased economic effect analysis, expenditure of local citizens, time switchers and casuals, UEFA super cup

Procedia PDF Downloads 143

Authors: Ola Jon Mork, Irina Emily Hansen

Abstract:

The European Growth Strategy Program calls for more efficient methods for knowledge creation and innovation. This study contributes with new insights into the Singapore Innovation System; more precisely how knowledge processes are facilitated. The research material is collected by visiting the different innovation locations in Singapore and depth interview with key persons. The different innovation actors web sites and brochures have been studied. Governmental reports and figures have also been studied. The findings show that facilitation of Knowledge Processes in the Singapore Innovation System has a basic structure with three processes, which is 1) Idea capturing – 2)Technology and Business Execution – 3)Idea Realization. Dedicated innovation parks work with the most promising entrepreneurs; more precisely: finding the persons with the motivation to 'change the world'. The innovation park will facilitate these entrepreneurs for 100 days, where they also will be connected to a global network of venture capital. And, the entrepreneurs will have access to mentors from these venture companies. Research institutes parks work with the development of world leading technology. To facilitate knowledge development they connect with industrial companies which are the most promising applicators of their technology. Knowledge facilitation is the main purpose, but this cooperation/testing is also serving as a platform for funding. Probably this is cooperation is also attractive for world leading companies. Dedicated innovation parks work with facilitation of innovators of new applications and perfection of products for the end- user. These parks can be specialized in special areas, like health products and life science products. Another example of this is automotive companies giving research call for these parks to develop and innovate new products and services upon their technology. Common characteristics for the knowledge facilitation in the Singapore Innovation System are a short trial period for promising actors, normally 100 days. It is also a strong focus on training of the entrepreneurs. Presentations and diffusion of knowledge is an important part of the facilitation. Funding will be available for the most successful entrepreneurs and innovators.

Keywords: knowledge processes, facilitation, innovation, Singapore innovation web

Procedia PDF Downloads 290

Authors: Vasileiou Apostolos, Theodosiou Chrysa, Tsitroulis Ioannis, Maris Fotios

Abstract:

The severity of extreme phenomena is due to their ability to cause severe damage in a small amount of time. It has been observed that floods affect the greatest number of people and induce the biggest damage when compared to the total of annual natural disasters. The detection of potential flood-prone areas constitutes one of the fundamental components of the European Natural Disaster Management Policy, directly connected to the European Directive 2007/60. The aim of the present paper is to develop a new methodology that combines geographical information, fuzzy logic and multi-criteria evaluation methods so that the most vulnerable areas are defined. Therefore, ten factors related to geophysical, morphological, climatological/meteorological and hydrological characteristics of the basin were selected. Afterwards, two models were created to detect the areas pronest to flooding. The first model defined the gravitas of each factor using Analytical Hierarchy Process (AHP) and the final map of possible flood spots were created using GIS and Boolean Algebra. The second model made use of the fuzzy logic and GIS combination and a respective map was created. The application area of the aforementioned methodologies was in Ardas basin due to the frequent and important floods that have taken place these last years. Then, the results were compared to the already observed floods. The result analysis shows that both models can detect with great precision possible flood spots. As the fuzzy logic model is less time-consuming, it is considered the ideal model to apply to other areas. The said results are capable of contributing to the delineation of high risk areas and to the creation of successful management plans dealing with floods.

Keywords: analytical hierarchy process, flood prone areas, fuzzy logic, geographic information system

Procedia PDF Downloads 366

Authors: Juliana A. Galhardi, Daniel M. Bonotto

Abstract:

Coal is an important non-renewable energy source of and can be associated with radioactive elements. In Figueira city, Paraná state, Brazil, it was recorded high uranium activity near the coal mine that supplies a local thermoelectric power plant. In this context, the radon activity (Rn-222, produced by the Ra-226 decay in the U-238 natural series) was evaluated in groundwater, river water and effluents produced from the acid mine drainage in the coal reject dumps. The samples were collected in August 2013 and in February 2014 and analyzed at LABIDRO (Laboratory of Isotope and Hydrochemistry), UNESP, Rio Claro city, Brazil, using an alpha spectrometer (AlphaGuard) adjusted to evaluate the mean radon activity concentration in five cycles of 10 minutes. No radon activity concentration above 100 Bq.L-1, which was a previous critic value established by the World Health Organization. The average radon activity concentration in groundwater was higher than in surface water and in effluent samples, possibly due to the accumulation of uranium and radium in the aquifer layers that favors the radon trapping. The lower value in the river waters can indicate dilution and the intermediate value in the effluents may indicate radon absorption in the coal particles of the reject dumps. The results also indicate that the radon activities in the effluents increase with the sample acidification, possibly due to the higher radium leaching and the subsequent radon transport to the drainage flow. The water samples of Laranjinha River and Ribeirão das Pedras stream, which, respectively, supply Figueira city and receive the mining effluent, exhibited higher pH values upstream the mine, reflecting the acid mine drainage discharge. The radionuclides transport indicates the importance of monitoring their activity concentration in natural waters due to the risks that the radioactivity can represent to human health.

Keywords: radon, radium, acid mine drainage, coal

Procedia PDF Downloads 421

Authors: Dipak Sen, Rajdeep Ghosh

Abstract:

This paper presents a computational study of steady state three dimensional very high turbulent flow and heat transfer characteristics in a constant temperature-surfaced circular duct fitted with 900 hemispherical inline baffles. The computations are based on realizable k-ɛ model with standard wall function considering the finite volume method, and the SIMPLE algorithm has been implemented. Computational Study are carried out for Reynolds number, Re ranging from 80000 to 120000, Prandtl Number, Pr of 0.73, Pitch Ratios, PR of 1,2,3,4,5 based on the hydraulic diameter of the channel, hydrodynamic entry length, thermal entry length and the test section. Ansys Fluent 15.0 software has been used to solve the flow field. Study reveals that circular pipe having baffles has a higher Nusselt number and friction factor compared to the smooth circular pipe without baffles. Maximum Nusselt number and friction factor are obtained for the PR=5 and PR=1 respectively. Nusselt number increases while pitch ratio increases in the range of study; however, friction factor also decreases up to PR 3 and after which it becomes almost constant up to PR 5. Thermal enhancement factor increases with increasing pitch ratio but with slightly decreasing Reynolds number in the range of study and becomes almost constant at higher Reynolds number. The computational results reveal that optimum thermal enhancement factor of 900 inline hemispherical baffle is about 1.23 for pitch ratio 5 at Reynolds number 120000.It also shows that the optimum pitch ratio for which the baffles can be installed in such very high turbulent flows should be 5. Results show that pitch ratio and Reynolds number play an important role on both fluid flow and heat transfer characteristics.

Keywords: friction factor, heat transfer, turbulent flow, circular duct, baffle, pitch ratio

Procedia PDF Downloads 364

Authors: Azzah Alghamdi

Abstract:

The Interactive White Boards (IWBs) as one of the innovative educational technologies have been extensively investigated in advanced countries such as the UK, US, and Australia. However, there is a significant lack of research studies, which mainly examine the use of IWBs in Saudi Arabia. Therefore, this study aims to investigate the attitudes of primary teachers towards using IWBs in both the teaching and learning processes. Moreover, it aims to investigate if there is any significant difference between male teachers and females regarding their attitudes towards using this technology. This study concentrated on teachers in primary schools, which participated in Tatweer project in the city of Jeddah, in Saudi Arabia. Mixed methods approach was employed in this study using a designed questionnaire, classroom observations, and a semi-structured interview. 587 teachers (286 men and 301 women) from Tatweer primary schools were completed the questionnaire as well as twenty teachers were interviewed including seven female teachers were observed in their classrooms. The findings of this study indicated that approximately 11% of the teachers within the sample (n=587) had negative attitudes towards the use of IWBs in the teaching and learning processes. However, the majority of them nearly 89% agreed about the benefits of using IWBs in their classrooms. Additionally, all the twenty teachers who were interviewed (including the seven observed female teachers) had positive attitudes towards the use of these technologies. Moreover, 87% of male teachers and 91% of female teachers who completed the questionnaire accepted the usefulness of using IWBs in improving their teaching and students' learning. Thus, this indicates that there was no significant difference between male and female teachers in Tatweer primary schools in terms of their views about using these innovative technologies in their lessons. The findings of the current study will help the Ministry of Education to improve the policies of using IWBs in Saudi Arabia. Indeed, examining teachers’ attitudes towards IWBs is a very important issue because they are the main users in classrooms. Hence, their views should be considered to addressing the powers and boundaries of using IWBs. Moreover, students will feel comfortable to use IWBs if their teachers accept and use them well.

Keywords: IWBs, Saudi teachers’ views, Tatweer schools, teachers' gender

Procedia PDF Downloads 223

Authors: Umit Cali

Abstract:

The integration of intermittent energy sources like wind farms into the electricity grid has become an important challenge for the utilization and control of electric power systems, because of the fluctuating behaviour of wind power generation. Wind power predictions improve the economic and technical integration of large amounts of wind energy into the existing electricity grid. Trading, balancing, grid operation, controllability and safety issues increase the importance of predicting power output from wind power operators. Therefore, wind power forecasting systems have to be integrated into the monitoring and control systems of the transmission system operator (TSO) and wind farm operators/traders. The wind forecasts are relatively precise for the time period of only a few hours, and, therefore, relevant with regard to Spot and Intraday markets. In this work predictive data mining techniques are applied to identify a statistical and neural network model or set of models that can be used to predict wind power output of large onshore and offshore wind farms. These advanced data analytic methods helps us to amalgamate the information in very large meteorological, oceanographic and SCADA data sets into useful information and manageable systems. Accurate wind power forecasts are beneficial for wind plant operators, utility operators, and utility customers. An accurate forecast allows grid operators to schedule economically efficient generation to meet the demand of electrical customers. This study is also dedicated to an in-depth consideration of issues such as the comparison of day ahead and the short-term wind power forecasting results, determination of the accuracy of the wind power prediction and the evaluation of the energy economic and technical benefits of wind power forecasting.

Keywords: renewable energy sources, wind power, forecasting, data mining, big data, artificial intelligence, energy economics, power trading, power grids

Procedia PDF Downloads 505

Authors: Alper Cumhur, Hasan Baylavlı, Eren Gödek

Abstract:

Use of superplasticity chemical admixtures in concrete production is widespread all over the world and has become almost inevitable. Super-plasticizers (SPA), extend the setting time of concrete by adsorbing onto cement particles and provide concrete to preserve its fresh state workability properties. Hyper-plasticizers (HPA), as a special type of superplasticizer, provide the production of qualified concretes by increasing the workability properties of concrete, effectively. However, compatibility of cement with super and hyper-plasticizers is quite important for achieving efficient workability in order to produce qualified concretes. In 2011, the EN 197-1 standard is edited and cement classifications were updated. In this study, the compatibility of hyper-plasticizer and CEM I SR0 type sulphate resisting cement (SRC) that firstly classified in EN 197-1 is investigated. Within the scope of the experimental studies, a reference cement mortar was designed with a water/cement ratio of 0.50 confirming to EN 196-1. Fresh unit density of mortar was measured and spread diameters (at 0, 60, 120 min after mix preparation) and setting time of reference mortar were determined with flow table and Vicat tests, respectively. Three mortars are being re-prepared with using both super and hyper-plasticizer confirming to ASTM C494 by 0.50, 0.75 and 1.00% of cement weight. Fresh unit densities, spread diameters and setting times of super and hyper plasticizer added mortars (SPM, HPM) will be determined. Theoretical air-entrainment values of both SPMs and HPMs will be calculated by taking the differences between the densities of plasticizer added mortars and reference mortar. The flow table and Vicat tests are going to be repeated to these mortars and results will be compared. In conclusion, compatibility of SRC with SPA and HPA will be investigated. It is expected that optimum dosages of SPA and HPA will be determined for providing the required workability and setting conditions of SRC mortars, and the advantages/disadvantages of both SPA and HPA will be discussed.

Keywords: CEM I SR0, hyper-plasticizer, setting time, sulphate resisting cement, super-plasticizer, workability

Procedia PDF Downloads 209