Search results for: secondary compression index
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 7182

Search results for: secondary compression index

6912 Research on the Teaching Quality Evaluation of China’s Network Music Education APP

Authors: Guangzhuang Yu, Chun-Chu Liu

Abstract:

With the advent of the Internet era in recent years, social music education has gradually shifted from the original entity education mode to the mode of entity plus network teaching. No matter for school music education, professional music education or social music education, the teaching quality is the most important evaluation index. Regarding the research on teaching quality evaluation, scholars at home and abroad have contributed a lot of research results on the basis of multiple methods and evaluation subjects. However, to our best knowledge the complete evaluation model for the virtual teaching interaction mode of the emerging network music education Application (APP) has not been established. This research firstly found out the basic dimensions that accord with the teaching quality required by the three parties, constructing the quality evaluation index system; and then, on the basis of expounding the connotation of each index, it determined the weight of each index by using method of fuzzy analytic hierarchy process, providing ideas and methods for scientific, objective and comprehensive evaluation of the teaching quality of network education APP.

Keywords: network music education APP, teaching quality evaluation, index and connotation

Procedia PDF Downloads 93
6911 Effect of Treated Peat Soil on the Plasticity Index and Hardening Time

Authors: Siti Nur Aida Mario, Farah Hafifee Ahmad, Rudy Tawie

Abstract:

Soil Stabilization has been widely implemented in the construction industry nowadays. Peat soil is well known as one of the most problematic soil among the engineers. The procedures need to take into account both physical and engineering properties of the stabilized peat soil. This paper presents a result of plasticity index and hardening of treated peat soil with various dosage of additives. In order to determine plasticity of the treated peat soil, atterberg limit test which comprises plastic limit and liquid limit test has been conducted. Determination of liquid limit in this experimental study is by using cone penetrometer. Vicat testing apparatus has been used in the hardening test which the penetration of the plunger is recorded every one hour for 24 hours. The results show that the plasticity index of peat soil stabilized with 80% FAAC and 20% OPC has the lowest plasticity index and recorded the fastest initial setting time. The significant of this study is to promote greener solution for future soil stabilization industry.

Keywords: additives, hardening, peat soil, plasticity index, soil stabilization

Procedia PDF Downloads 295
6910 Dynamic Compaction Assessment for Improving Pasdaran Highway

Authors: Alireza Motamadnia, Roohollah Zohdi Oliayi, Hümeyra Bolakar, Ahmet Tortum

Abstract:

Dynamic compression as a method of soil improvement in recent decades has been considered by engineers and experts. Three methods mainly, deep dynamic compaction, soil density, dynamic and rapid change have been proposed and implemented to improve subgrade conditions of highway road. Northern highway route in Tabriz (Pasdaran), Iran that was placed on the manual soil was the main concern. Engineering properties of soil have been investigated experimentally and theoretically. Among the three methods rapid dynamic compaction for highway has been suggested to improve the soil subgrade conditions.

Keywords: manual soil, subsidence, improvement, dynamic compression

Procedia PDF Downloads 558
6909 Collaborative Managerial Practices of Heads of Educational Institutions: Principals and Students Perspective

Authors: Nasir Ahmed

Abstract:

The study was designed to explore the managerial practices of secondary school principals in collaboration with different school stakeholder’s i.e. Teachers, students and school councils. The population of the study comprised 41 principals of government secondary schools, 249 Secondary school teachers (SSTs), 3360 students of 10th class and 300 members of the school councils of government secondary schools (both boys and girls) in Wazirabad, Pakistan. 50 percentage principals, 40 percentage SSTs, 3 percentage students and 15% members of the school councils were taken as a sample of the study. Data was collected through different four-questionnaire design on a five point rating scale. The questionnaires for teachers, students, and school councils were developed to see their involvement in school management. The questionnaire for the secondary school principals was designed to find out to see their perceptions about the involvement of these stakeholders in school’s management. The results of the students indicated that, the remaining stakeholders were not cooperating with the school management. It was recommended that all the stakeholders be provided equal opportunities to take an active part in the school management. This may be based on a formal mechanism for the collaborative efforts of all the stakeholders.

Keywords: collaboration, management, school stakeholders, school councils, managerial practices

Procedia PDF Downloads 252
6908 The Analysis of Secondary Case Studies as a Starting Point for Grounded Theory Studies: An Example from the Enterprise Software Industry

Authors: Abilio Avila, Orestis Terzidis

Abstract:

A fundamental principle of Grounded Theory (GT) is to prevent the formation of preconceived theories. This implies the need to start a research study with an open mind and to avoid being absorbed by the existing literature. However, to start a new study without an understanding of the research domain and its context can be extremely challenging. This paper presents a research approach that simultaneously supports a researcher to identify and to focus on critical areas of a research project and prevent the formation of prejudiced concepts by the current body of literature. This approach comprises of four stages: Selection of secondary case studies, analysis of secondary case studies, development of an initial conceptual framework, development of an initial interview guide. The analysis of secondary case studies as a starting point for a research project allows a researcher to create a first understanding of a research area based on real-world cases without being influenced by the existing body of theory. It enables a researcher to develop through a structured course of actions a firm guide that establishes a solid starting point for further investigations. Thus, the described approach may have significant implications for GT researchers who aim to start a study within a given research area.

Keywords: grounded theory, interview guide, qualitative research, secondary case studies, secondary data analysis

Procedia PDF Downloads 239
6907 Patella Proximo-Distal Displacement Following Modified Maquet Technique

Authors: T. Giansetto, E. Pierrot, P. Picavet, M. Lefebvre, S. Claeys, M. Balligand

Abstract:

Objective: To test the low sensitivity of the Allberg and Miles index to the stifle opening angle, to evaluate the displacement of the patella after a Modified Maquet Technique using this index, and to assess the incidence of patella luxation post-Modified Maquet Technique in dogs. Materials and methods: Medical records were reviewed from 2012 to 2017. Allberg Miles index was determined for each stifle pre and post-operatively, as well as the stifle joint opening of each case. The occurrence of patella luxation was recorded. Results: 137 stifles on 116 dogs were reviewed. The stifle opening angle did not influence the Allberg Miles index (p=0.41). Pre and post-operative index showed a distal displacement of the patella after a Modified Maquet Procedure, especially at a 90° of stifle opening angle. Only 1/137 cases demonstrated patella luxation after the surgery. Conclusion: The Allberg Miles radiographic index is largely independent of the stifle opening angle and can be used to assess the proximo-distal position of the patella in relation to the femoral trochlear groove. If patella baja is clearly induced by the Modified Maquet Technique, the latter does not seem to predispose patients to post-operative patella luxation in a large variety of dog breeds.

Keywords: rlca, modified Maquet technique, patella luxation, orthopedic

Procedia PDF Downloads 94
6906 Analysis of Enhanced Built-up and Bare Land Index in the Urban Area of Yangon, Myanmar

Authors: Su Nandar Tin, Wutjanun Muttitanon

Abstract:

The availability of free global and historical satellite imagery provides a valuable opportunity for mapping and monitoring the year by year for the built-up area, constantly and effectively. Land distribution guidelines and identification of changes are important in preparing and reviewing changes in the ground overview data. This study utilizes Landsat images for thirty years of information to acquire significant, and land spread data that are extremely valuable for urban arranging. This paper is mainly introducing to focus the basic of extracting built-up area for the city development area from the satellite images of LANDSAT 5,7,8 and Sentinel 2A from USGS in every five years. The purpose analyses the changing of the urban built-up area according to the year by year and to get the accuracy of mapping built-up and bare land areas in studying the trend of urban built-up changes the periods from 1990 to 2020. The GIS tools such as raster calculator and built-up area modelling are using in this study and then calculating the indices, which include enhanced built-up and bareness index (EBBI), Normalized difference Built-up index (NDBI), Urban index (UI), Built-up index (BUI) and Normalized difference bareness index (NDBAI) are used to get the high accuracy urban built-up area. Therefore, this study will point out a variable approach to automatically mapping typical enhanced built-up and bare land changes (EBBI) with simple indices and according to the outputs of indexes. Therefore, the percentage of the outputs of enhanced built-up and bareness index (EBBI) of the sentinel-2A can be realized with 48.4% of accuracy than the other index of Landsat images which are 15.6% in 1990 where there is increasing urban expansion area from 43.6% in 1990 to 92.5% in 2020 on the study area for last thirty years.

Keywords: built-up area, EBBI, NDBI, NDBAI, urban index

Procedia PDF Downloads 124
6905 Cloud Resources Utilization and Science Teacher’s Effectiveness in Secondary Schools in Cross River State, Nigeria

Authors: Michael Udey Udam

Abstract:

Background: This study investigated the impact of cloud resources, a component of cloud computing, on science teachers’ effectiveness in secondary schools in Cross River State. Three (3) research questions and three (3) alternative hypotheses guided the study. Method: The descriptive survey design was adopted for the study. The population of the study comprised 1209 science teachers in public secondary schools of Cross River state. Sample: A sample of 487 teachers was drawn from the population using a stratified random sampling technique. The researcher-made structured questionnaire with 18 was used for data collection for the study. Research question one was answered using the Pearson Product Moment Correlation, while research question two and the hypotheses were answered using the Analysis of Variance (ANOVA) statistics in the Statistical Package for Social Sciences (SPSS) at a 0.05 level of significance. Results: The results of the study revealed that there is a positive correlation between the utilization of cloud resources in teaching and teaching effectiveness among science teachers in secondary schools in Cross River state; there is a negative correlation between gender and utilization of cloud resources among science teachers in secondary schools in Cross River state; and that there is a significant correlation between teaching experience and the utilization of cloud resources among science teachers in secondary schools in Cross River state. Conclusion: The study justifies the effectiveness of the Cross River state government policy of introducing cloud computing into the education sector. The study recommends that the policy should be sustained.

Keywords: cloud resources, science teachers, effectiveness, secondary school

Procedia PDF Downloads 39
6904 Study the Efficiency of Some Homopolymers as Lube Oil Additives

Authors: Amal M. Nassar, Nehal S. Ahmed, Rasha S. Kamal

Abstract:

Some lube oil additives improve the base oil performance such as viscosity index improvers and pour point depressants which are the most important type of additives. In the present work, some homopolymeric additives were prepared by esterification of acrylic acid with different alcohols (1-dodecyl, 1-hexadecyl, and 1-octadecyl )and then homopolymerization of the prepared esters with different ratio of benzoyl peroxide catalyst (0.25%& 0.5 % and 1%). Structure of the prepared esters was confirmed by Infra-Red Spectroscopy. The molecular weights of the prepared homopolymers were determined by using Gel Permeation Chromatograph. The efficiency of the prepared homopolymers as viscosity index improvers and pour point depressants for lube oil was the investigation. It was found that all the prepared homopolymers are effective as viscosity index improvers and pour point depressants.

Keywords: lube oil additives, homopolymerization, viscosity index improver, pour point depressant

Procedia PDF Downloads 192
6903 A Qualitative Case Study Exploring Zambian Mathematics Teachers' Content Knowledge of Functions

Authors: Priestly Malambo, Sonja Van Putten, Hanlie Botha, Gerrit Stols

Abstract:

The relevance of what is content is taught in tertiary teacher training has long been in question. This study attempts to understand how advanced mathematics courses equip student teachers to teach functions at secondary school level. This paper reports on an investigation that was conducted in an African university, where preservice teachers were purposefully selected for participation in individual semi-structured interviews after completing a test on functions as taught at secondary school. They were asked to justify their reasoning in the test and to explain functions in a way that might bring about understanding of the topic in someone who did not know how functions work. These were final year preservice mathematics teachers who had studied advanced mathematics courses for three years. More than 50% of the students were not able to explain concepts or to justify their reasoning about secondary school functions in a coherent way. The results of this study suggest that the study of advanced mathematics does not automatically enable students to teach secondary school functions, and that, although these students were able to do advanced mathematics, they were unable to explain the working of functions in a way that would allow them to teach this topic successfully.

Keywords: secondary school, mathematical reasoning, student-teachers, functions

Procedia PDF Downloads 237
6902 Gender, Tutoring, and Track in Egyptian Education

Authors: Eman Shady, Ray Langsten

Abstract:

In Egypt, girls have traditionally been educationally disadvantaged. This disadvantage, however, has been focused on the failure to enter school. Increasingly it is recognized that girls who ever-enroll are at least as likely to complete primary and secondary education as boys. Still the belief persists that girls, especially those from poor families, will be disadvantaged in terms of school expenditures and the transitions to secondary and higher education. We use data from the 2005-06 Egypt Household Education Survey to examine expenditures on tutoring during the final year of preparatory school, and the transition to specific tracks of secondary education. Tests during the last year of preparatory largely determine a student’s educational future. Results show that girls, even girls from poor families, are not disadvantaged in terms of expenditures, whether for tutoring, fees or general expenses. Moreover, girls are more likely than boys to advance to general secondary education, the track that leads to higher education.

Keywords: gender, tutoring, track, Egypt

Procedia PDF Downloads 362
6901 Groundwater Quality Assessment Using Water Quality Index and Geographical Information System Techniques: A Case Study of Busan City, South Korea

Authors: S. Venkatramanan, S. Y. Chung, S. Selvam, E. E. Hussam, G. Gnanachandrasamy

Abstract:

The quality of groundwater was evaluated by major ions concentration around Busan city, South Korea. The groundwater samples were collected from 40 wells. The order of abundance of major cations concentration in groundwater is Na > Ca > Mg > K, in case of anions are Cl > HCO₃ > SO₄ > NO₃ > F. Based on Piper’s diagram Ca (HCO₃)₂, CaCl₂, and NaCl are the leading groundwater types. While Gibbs diagram suggested that most of groundwater samples belong to rock-weathering zone. Hydrogeochemical condition of groundwater in this city is influenced by evaporation, ion exchange and dissolution of minerals. Water Quality Index (WQI) revealed that 86 % of the samples belong to excellent, 2 % good, 4 % poor to very poor and 8 % unsuitable categories. The results of sodium absorption ratio (SAR), Permeability Index (PI), Residual Sodium Carbonate (RSC) and Magnesium Hazard (MH) exhibit that most of the groundwater samples are suitable for domestic and irrigation purposes.

Keywords: WQI (Water Quality Index), saturation index, groundwater types, ion exchange

Procedia PDF Downloads 231
6900 Application of Basic Principles of Educational Administration for the Enhancement of Senior Secondary School Principals in Kano State Nigeria

Authors: Ibrahim Auwal

Abstract:

This study focuses on senior secondary education towards the development of younger generation in general terms, and specifically for the enhancement of senior secondary school principals. Investigation was made to correlate between principals’ application of basic principles of educational administration and principals’ productivity in senior secondary schools in Kano State. The instrument used to collect relevant data was self designed Observation Inventory for School Principals (OISP). The observation inventory items were scrutinized by experts from the School of Education Federal College of Education Kano to ascertain the contents validity, and the reliability coefficient was 0.83. Using purposive sampling technique, 30 schools were chosen from 85 senior secondary schools in Kano state and 30 principals were deliberately sampled due to their small number. Pearson Product Moment Correlation (r) Coefficient was used to test the hypothesis generated for the study. The results of the analysis showed that principals’ application of basic principles of educational administration was significantly correlated with principals’ productivity and it promote the performance of the students. Based on the findings, it was recommended that, government should in as much as possible encourage school principals to obtain degrees in relevant and specialized areas in education specifically educational administration and planning so as to get all the necessary knowledge and skills of leader ship procedures that will definitely promote teachers morale, improve students’ academic performance and enhances principals’ productivity in senior secondary schools in Kano State.

Keywords: principles of educational administration, principals of senior secondary schools, Kano, educational sciences

Procedia PDF Downloads 459
6899 Communicative Language Teaching in English as a Foreign Language Classrooms: An Overview of Secondary Schools in Bangladesh

Authors: Saifunnahar

Abstract:

As a former English colony, the relationship of Bangladesh with the English language goes a long way back. English is taught as a compulsory subject in Bangladesh from an early age starting from grade 1 and continuing through the 12th, yet, students are not competent enough to communicate in English proficiently. To improve students’ English language competency, the Bangladesh Ministry of Education introduced communicative language teaching (CLT) methods in English classrooms in the 1990s. It has been decades since this effort was taken, but the students’ level of proficiency is still not satisfactory. The main reason behind this failure is that CLT-based teaching-learning methods have not been effectively implemented. Very little research has been conducted to address the issues English as a foreign language (EFL) classrooms are facing to carry out CLT methodologies in secondary schools (grades 6 to 10) in Bangladesh. Though the secondary level is crucial for students’ language learning and retention, EFL classrooms are marked with various issues that make teaching-learning harder for teachers and students. This study provides an overview of the status of CLT in EFL classrooms and the reasons behind failing to implement CLT in secondary schools in Bangladesh through an analysis of the qualitative data collected from different literature. Based on the findings, effective approaches have been recommended to employ CLT in EFL classrooms.

Keywords: Bangladesh, communicative language teaching, English as a foreign language, secondary schools, pedagogy

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6898 Effects of Cognitive Reframe on Depression among Secondary School Adolescents: The Moderating Role of Self-Esteem

Authors: Olayinka M. Ayannuga

Abstract:

This study explored the effect of cognitive reframe in reducing depression among Senior Secondary School Adolescents. It adopted a pre-test, post-test, control quasi-experimental research design with a 2x2 factorial matrix. Participants included 120 depressed adolescents randomly drawn from public Senior Secondary School Two (SSS.II) students in Lagos State, Nigeria. Sixty participants were randomly selected and assigned to the treatment and control groups. Participants in the Cognitive Reframe (CR) group were trained for 8 weeks, while those in the Control group were given a placebo. Two instruments were used for data collection namely: Self – Esteem Scale (SES: Rosenberg 1965: α = 0.85), and The Self Rating Depression Scale (SDS: Zung, 1972; α 0 = 0.87) were administered at pretest level. However, only the Self-Rating Depression Scale (SDS) was re-administered at post-test to measure the effect of the intervention. The results revealed that there was a significant effect of cognitive reframe training programmes on secondary school adolescents’ depression, also there were significant effects of self-esteem on secondary school adolescents’ depression. The study showed that the technique is capable of reducing depression among adolescents. It was recommended, amongst others, that Counselling psychologists, Curriculum planners and Teachers could explore incorporating the contents of cognitive reframe into the secondary school curriculum for students’ capacity building to reduce depression tendencies.

Keywords: adolescents, cognitive reframe, depression, self – esteem

Procedia PDF Downloads 221
6897 Constitutive Modeling of Different Types of Concrete under Uniaxial Compression

Authors: Mostafa Jafarian Abyaneh, Khashayar Jafari, Vahab Toufigh

Abstract:

The cost of experiments on different types of concrete has raised the demand for prediction of their behavior with numerical analysis. In this research, an advanced numerical model has been presented to predict the complete elastic-plastic behavior of polymer concrete (PC), high-strength concrete (HSC), high performance concrete (HPC) along with different steel fiber contents under uniaxial compression. The accuracy of the numerical response was satisfactory as compared to other conventional simple models such as Mohr-Coulomb and Drucker-Prager. In order to predict the complete elastic-plastic behavior of specimens including softening behavior, disturbed state concept (DSC) was implemented by nonlinear finite element analysis (NFEA) and hierarchical single surface (HISS) failure criterion, which is a failure surface without any singularity.

Keywords: disturbed state concept (DSC), hierarchical single surface (HISS) failure criterion, high performance concrete (HPC), high-strength concrete (HSC), nonlinear finite element analysis (NFEA), polymer concrete (PC), steel fibers, uniaxial compression test

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6896 Mechanical Response of Aluminum Foam Under Biaxial Combined Quasi-Static Compression-Torsional Loads

Authors: Solomon Huluka, Akrum Abdul-Latif, Rachid Baleh

Abstract:

Metal foams have been developed intensively as a new class of materials for the last two decades due to their unique structural and multifunctional properties. The aim of this experimental work was to characterize the effect of biaxial loading complexity (combined compression-torsion) on the plastic response of highly uniform architecture open-cell aluminum foams of spherical porous with a density of 80%. For foam manufacturing, the Kelvin cells model was used to generate the generally spherical shape with a cell diameter of 11 mm. A patented rig called ACTP (Absorption par Compression-Torsion Plastique), was used to investigate the foam response under quasi-static complex loading paths having different torsional components (i.e. 0°, 45° and 60°). The key mechanical responses to be examined are yield stress, stress plateau, and energy absorption capacity. The collapse mode was also investigated. It was concluded that the higher the loading complexity, the greater the yield strength and the greater energy absorption capacity of the foam. Experimentally, it was also noticed that there were large softening effects that occurred after the first pick stress for both biaxial-45° and biaxial-60° loading.

Keywords: aluminum foam, loading complexity, characterization, biaxial loading

Procedia PDF Downloads 95
6895 Air Classification of Dust from Steel Converter Secondary De-dusting for Zinc Enrichment

Authors: C. Lanzerstorfer

Abstract:

The off-gas from the basic oxygen furnace (BOF), where pig iron is converted into steel, is treated in the primary ventilation system. This system is in full operation only during oxygen-blowing when the BOF converter vessel is in a vertical position. When pig iron and scrap are charged into the BOF and when slag or steel are tapped, the vessel is tilted. The generated emissions during charging and tapping cannot be captured by the primary off-gas system. To capture these emissions, a secondary ventilation system is usually installed. The emissions are captured by a canopy hood installed just above the converter mouth in tilted position. The aim of this study was to investigate the dependence of Zn and other components on the particle size of BOF secondary ventilation dust. Because of the high temperature of the BOF process it can be expected that Zn will be enriched in the fine dust fractions. If Zn is enriched in the fine fractions, classification could be applied to split the dust into two size fractions with a different content of Zn. For this air classification experiments with dust from the secondary ventilation system of a BOF were performed. The results show that Zn and Pb are highly enriched in the finest dust fraction. For Cd, Cu and Sb the enrichment is less. In contrast, the non-volatile metals Al, Fe, Mn and Ti were depleted in the fine fractions. Thus, air classification could be considered for the treatment of dust from secondary BOF off-gas cleaning.

Keywords: air classification, converter dust, recycling, zinc

Procedia PDF Downloads 405
6894 A Method for Processing Unwanted Target Caused by Reflection in Secondary Surveillance Radar

Authors: Khanh D.Do, Loi V.Nguyen, Thanh N.Nguyen, Thang M.Nguyen, Vu T.Tran

Abstract:

Along with the development of Secondary surveillance radar (SSR) in air traffic surveillance systems, the Multipath phenomena has always been a noticeable problem. This following article discusses the geometrical aspect and power aspect of the Multipath interference caused by reflection in SSR and proposes a method to deal with these unwanted multipath targets (ghosts) by false-target position predicting and adaptive target suppressing. A field-experiment example is mentioned at the end of the article to demonstrate the efficiency of this measure.

Keywords: multipath, secondary surveillance radar, digital signal processing, reflection

Procedia PDF Downloads 120
6893 Exergy Analysis of Vapour Compression Refrigeration System Using R507A, R134a, R114, R22 and R717

Authors: Ali Dinarveis

Abstract:

This paper compares the energy and exergy efficiency of a vapour compression refrigeration system using refrigerants of different groups. In this study, five different refrigerants including R507A, R134a, R114, R22 and R717 have been studied. EES Program is used to solve the thermodynamic equations. The results of this analysis are shown graphically. Based on the results, energy and exergy efficiencies for R717 are higher than the other refrigerants. Also, the energy and exergy efficiencies will be decreased with increasing the condensing temperature and decreasing the evaporating temperature.

Keywords: Energy, Exergy, Refrigeration, thermodynamic, vapour

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6892 Enhancing the Performance of Vapor Compression Refrigeration Systems Using HFC134a by Nanoparticles Suspensions

Authors: Hafsi Khebab, Zirari Mounir, Mohamed Nadjib Bouaziz

Abstract:

High Global Warming Potential refrigerants (HydroFluroCarbons) are one of the worst greenhouse gases used in a wide variety of applications, including refrigeration and air-conditioning. Nanotechnology is a promising field in sustainable energy to reduce energy and ecological resource consumption for HVACR (heat, ventilation, air conditioning, and refrigeration) systems. Most researchers reported an improvement in heat transfer coefficient, Coefficient of performance. In this report, a brief summary has been done on the performance enhancement of the Vapor Compression Refrigeration system using HFC134a with nano refrigerants.

Keywords: nanorefrigerant, HFCs, greenhouse gases, GWP, HVACR systems, energy saving

Procedia PDF Downloads 51
6891 Influence of Pine Wood Ash as Pozzolanic Material on Compressive Strength of a Concrete

Authors: M. I. Nicolas, J. C. Cruz, Ysmael Verde, A.Yeladaqui-Tello

Abstract:

The manufacture of Portland cement has revolutionized the construction industry since the nineteenth century; however, the high cost and large amount of energy required on its manufacturing encouraged, from the seventies, the search of alternative materials to replace it partially or completely. Among the materials studied to replace the cement are the ashes. In the city of Chetumal, south of the Yucatan Peninsula in Mexico, there are no natural sources of pozzolanic ash. In the present study, the cementitious properties of artificial ash resulting from the combustion of waste pine wood were analyzed. The ash obtained was sieved through the screen and No.200 a fraction was analyzed using the technique of X-ray diffraction; with the aim of identifying the crystalline phases and particle sizes of pozzolanic material by the Debye-Scherrer equation. From the characterization of materials, mixtures for a concrete of f'c = 250 kg / cm2 were designed with the method ACI 211.1; for the pattern mixture and for partial replacements of Portland cement by 5%, 10% and 12% pine wood ash mixture. Simple resistance to axial compression of specimens prepared with each concrete mixture, at 3, 14 and 28 days of curing was evaluated. Pozzolanic activity was observed in the ash obtained, checking the presence of crystalline silica (SiO2 of 40.24 nm) and alumina (Al2O3 of 35.08 nm). At 28 days of curing, the specimens prepared with a 5% ash, reached a compression resistance 63% higher than design; for specimens with 10% ash, was 45%; and for specimens with 12% ash, only 36%. Compared to Pattern mixture, which after 28 days showed a f'c = 423.13 kg/cm2, the specimens reached only 97%, 86% and 82% of the compression resistance, for mixtures containing 5%, 10% ash and 12% respectively. The pozzolanic activity of pine wood ash influences the compression resistance, which indicates that it can replace up to 12% of Portland cement by ash without compromising its design strength, however, there is a decrease in strength compared to the pattern concrete.

Keywords: concrete, pine wood ash, pozzolanic activity, X-ray

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6890 Evaluation and Provenance Studies of Heavy Mineral Deposits in Recent Sediment of Ologe Lagoon, South Western, Nigeria

Authors: Mayowa Philips Ibitola, Akinade-Solomon Olorunfemi, Abe Oluwaseun Banji

Abstract:

Heavy minerals studies were carried out on eighteen sediment samples from Ologe lagoon located at Lagos Barrier complex, with the aim of evaluating the heavy mineral deposits and determining the provenance of the sediments. The samples were subjected to grain analysis techniques in order to collect the finest grain size. Separation of heavy minerals from the samples was done with the aid of bromoform to enable petrographic analyses of the heavy mineral suite, under the polarising microscope. The data obtained from the heavy mineral analysis were used in preparing histograms and pie chart, from which the individual heavy mineral percentage distribution and ZTR index were derived. The percentage composition of the individual heavy mineral analyzed are opaque mineral 63.92%, Zircon 12.43%, Tourmaline 5.79%, Rutile 13.44%, Garnet 1.74% and Staurolite 3.52%. The calculated zircon, tourmaline, rutile index in percentage (ZTR) varied between 76.13 -92.15%, average garnet-zircon index (GZI), average rutile-zircon index (RuZI) and average staurolite-zircon index values in all the stations are 16.18%, 54.33%, 25.11% respectively. The mean ZTR index percentage value is 85.17% indicates that the sediments within the lagoon are mineralogically matured. The high percentage of zircon, rutile, and tourmaline indicates an acid igneous rock source for the sediments. However, the low percentage of staurolite, rutile and garnet occurrence indicates sediment of metamorphic rock source input.

Keywords: lagoon, provenance, heavy mineral, ZTR index

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6889 Instability Index Method and Logistic Regression to Assess Landslide Susceptibility in County Route 89, Taiwan

Authors: Y. H. Wu, Ji-Yuan Lin, Yu-Ming Liou

Abstract:

This study aims to set up the landslide susceptibility map of County Route 89 at Ren-Ai Township in Nantou County using the Instability Index Method and Logistic regression. Seven susceptibility factors including Slope Angle, Aspect, Elevation, Distance to fold, Distance to River, Distance to Road and Accumulated Rainfall were obtained by GIS based on the Typhoon Toraji landslide area identified by Industrial Technology Research Institute in 2001. To calculate the landslide percentage of each factor and acquire the weight and grade the grid by means of Instability Index Method. In this study, landslide susceptibility can be classified into four grades: high, medium high, medium low and low, in order to determine the advantages and disadvantages of the two models. The precision of this model is verified by classification error matrix and SRC curve. These results suggest that the logistic regression model is a preferred method than instability index in the assessment of landslide susceptibility. It is suitable for the landslide prediction and precaution in this area in the future.

Keywords: instability index method, logistic regression, landslide susceptibility, SRC curve

Procedia PDF Downloads 259
6888 Perceptual Image Coding by Exploiting Internal Generative Mechanism

Authors: Kuo-Cheng Liu

Abstract:

In the perceptual image coding, the objective is to shape the coding distortion such that the amplitude of distortion does not exceed the error visibility threshold, or to remove perceptually redundant signals from the image. While most researches focus on color image coding, the perceptual-based quantizer developed for luminance signals are always directly applied to chrominance signals such that the color image compression methods are inefficient. In this paper, the internal generative mechanism is integrated into the design of a color image compression method. The internal generative mechanism working model based on the structure-based spatial masking is used to assess the subjective distortion visibility thresholds that are visually consistent to human eyes better. The estimation method of structure-based distortion visibility thresholds for color components is further presented in a locally adaptive way to design quantization process in the wavelet color image compression scheme. Since the lowest subband coefficient matrix of images in the wavelet domain preserves the local property of images in the spatial domain, the error visibility threshold inherent in each coefficient of the lowest subband for each color component is estimated by using the proposed spatial error visibility threshold assessment. The threshold inherent in each coefficient of other subbands for each color component is then estimated in a local adaptive fashion based on the distortion energy allocation. By considering that the error visibility thresholds are estimated using predicting and reconstructed signals of the color image, the coding scheme incorporated with locally adaptive perceptual color quantizer does not require side information. Experimental results show that the entropies of three color components obtained by using proposed IGM-based color image compression scheme are lower than that obtained by using the existing color image compression method at perceptually lossless visual quality.

Keywords: internal generative mechanism, structure-based spatial masking, visibility threshold, wavelet domain

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6887 Interaction of Local, Flexural-Torsional, and Flexural Buckling in Cold-Formed Steel Lipped-Angle Compression Members

Authors: K. C. Kalam Aswathy, M. V. Anil Kumar

Abstract:

The possible failure modes of cold-formed steel (CFS) lipped angle (LA) compression members are yielding, local, flexural-torsional, or flexural buckling, and any possible interaction between these buckling modes. In general, the strength estimated by current design guidelines is conservative for these members when flexural-torsional buckling (FTB) is the first global buckling mode, as the post-buckling strength of this mode is not accounted for in the global buckling strength equations. The initial part of this paper reports the results of an experimental and numerical study of CFS-LA members undergoing independent FTB. The modifications are suggested to global buckling strength equations based on these results. Subsequently, the reduction in the ultimate strength from strength corresponding to independent buckling modes for LA members undergoing interaction between buckling modes such as local-flexural torsional, flexural-flexural torsional, local-flexural, and local-flexural torsional-flexural are studied systematically using finite element analysis results. A simple and more accurate interaction equation that accounts for the above interactions between buckling modes in CFS-LA compression members is proposed.

Keywords: buckling interactions, cold-formed steel, flexural-torsional buckling, lipped angle

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6886 Analysis of Computer Science Papers Conducted by Board of Intermediate and Secondary Education at Secondary Level

Authors: Ameema Mahroof, Muhammad Saeed

Abstract:

The purpose of this study was to analyze the papers of computer science conducted by Board of Intermediate and Secondary Education with reference to Bloom’s taxonomy. The present study has two parts. First, the analysis is done on the papers conducted by Board of Intermediate of Secondary Education on the basis of basic rules of item construction especially Bloom’s (1956). And the item analysis is done to improve the psychometric properties of a test. The sample included the question papers of computer science of higher secondary classes (XI-XII) for the years 2011 and 2012. For item analysis, the data was collected from 60 students through convenient sampling. Findings of the study revealed that in the papers by Board of intermediate and secondary education the maximum focus was on knowledge and understanding level and very less focus was on the application, analysis, and synthesis. Furthermore, the item analysis on the question paper reveals that item difficulty of most of the questions did not show a balanced paper, the items were either very difficult while most of the items were too easy (measuring knowledge and understanding abilities). Likewise, most of the items were not truly discriminating the high and low achievers; four items were even negatively discriminating. The researchers also analyzed the items of the paper through software Conquest. These results show that the papers conducted by Board of Intermediate and Secondary Education were not well constructed. It was recommended that paper setters should be trained in developing the question papers that can measure various cognitive abilities of students so that a good paper in computer science should assess all cognitive abilities of students.

Keywords: Bloom’s taxonomy, question paper, item analysis, cognitive domain, computer science

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6885 Experimental Studies of Spiral-Confined HSCFST Columns under Uni-Axial Compression

Authors: Mianheng Lai, Johnny Ching Ming Ho, Hoat Joen Pam

Abstract:

Concrete-filled-steel-tube (CFST) columns are becoming increasingly popular owing to the superior behavior contributed by the composite action. However, this composite action cannot be fully developed because of different dilation properties between steel tube and concrete. During initial compression, there will be de-bonding between the constitutive materials. As a result, the strength, initial stiffness and ductility of CFST columns reduce significantly. To resolve this problem, external confinement in the form of spirals is proposed to improve the interface bonding. In this paper, a total of 14CFST columns with high-strength as well as ultra-high-strength concrete in-filled were fabricated and tested under uni-axial compression. From the experimental results, it can be concluded that the proposed spirals can improve the strength, initial stiffness, ductility and the interface bonding condition of CFST columns by restraining the lateral expansion of steel tube and core concrete. Moreover, the failure modes of confined core concrete change due to the strong confinement provided by spirals.

Keywords: concrete-filled-steel-tube, confinement, failure mode, high-strength concrete, spirals

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6884 Evaluation of Zooplankton Community and Saprobi Index of Carps Culture Ponds: Case Study on East of Golestan Province-Gonbade Kavous City

Authors: Mehrdad Kamali-Sanzighi, Maziar Kamali-Sanzighi

Abstract:

The aim of this research was to study zooplankton community density, diversity and Saprobi index in carp ponds at Golestan province, Gonbade Kavous city, Iran. Zooplankton sampling was done monthly in each pond during one carp culture time. Our analysis showed 27 genus from 4 groups (Protozoa 12, Rotatoria 8, Copepoda 4 and Cladocera 3). The highest and lowest frequency of zooplankton groups were belongs to Rotatoria, Copepoda, Cladocera and Protozoa with 46, 28, 23 and 3 percent, respectively. No significant differences between saprobi index of six carp ponds (P>0.05) were observed. Saprobi index indicated Class ßmesosaprob for six analysis ponds. There was a general tendency to decrease and significantly in the saprobi index with the value range of 1.52-1.70 from the beginning to end of the culture season (P<0.05). Also, gradual improvement of water quality observed toward the end of culture period and these reasons are partly a result of natural and management processed such as seasons changes (climate), water exchange (replacement of water) and pause of introduce of fertilizer materials to the ponds. According to the ability of saprobi index in monitoring of water quality condition and health of different water resources, focus to similar kind of effective research is necessary in future time.

Keywords: zooplankton, saprobi pollution index, water quality, fish pond, east of Golestan Province

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6883 Effect of Fines on Liquefaction Susceptibility of Sandy Soil

Authors: Ayad Salih Sabbar, Amin Chegenizadeh, Hamid Nikraz

Abstract:

Investigation of liquefaction susceptibility of materials that have been used in embankments, slopes, dams, and foundations is very essential. Many catastrophic geo-hazards such as flow slides, declination of foundations, and damage to earth structure are associated with static liquefaction that may occur during abrupt shearing of these materials. Many artificial backfill materials are mixtures of sand with fines and other composition. In order to provide some clarifications and evaluations on the role of fines in static liquefaction behaviour of sand sandy soils, the effect of fines on the liquefaction susceptibility of sand was experimentally examined in the present work over a range of fines content, relative density, and initial confining pressure. The results of an experimental study on various sand-fines mixtures are presented. Undrained static triaxial compression tests were conducted on saturated Perth sand containing 5% bentonite at three different relative densities (10, 50, and 90%), and saturated Perth sand containing both 5% bentonite and slag (2%, 4%, and 6%) at single relative density 10%. Undrained static triaxial tests were performed at three different initial confining pressures (100, 150, and 200 kPa). The brittleness index was used to quantify the liquefaction potential of sand-bentonite-slag mixtures. The results demonstrated that the liquefaction susceptibility of sand-5% bentonite mixture was more than liquefaction susceptibility of clean sandy soil. However, liquefaction potential decreased when both of two fines (bentonite and slag) were used. Liquefaction susceptibility of all mixtures decreased with increasing relative density and initial confining pressure.  

Keywords: liquefaction, bentonite, slag, brittleness index

Procedia PDF Downloads 193