Mechanical properties and thermal behaviour of two-stage concrete containing palm oil fuel ash

Two-stage concrete (TSC) is a special type of concrete which is made by placing coarse aggregate in a formwork and injecting a grout either by pump or under the gravity force to fill the voids. Over the decades, the application of supplementary cementing materials in conventional concrete has become widespread, and this trend is expected to continue in TSC as well. Palm oil fuel ash (POFA) is one of the ashes which has been recognized as a good pozzolanic material. This paper presents the experimental results on the performance behaviour of POFA in developing physical and mechanical properties of two-stage concrete. Four concrete mixes namely, TSC with 100% OPC as a control, and TSC with 10, 20 and 30% POFA were cast, and the temperature growth due to heat of hydration and heat transfer in the mixes was recorded. It has been found that POFA significantly reduced the temperature rise in two-stage aggregate concrete and delayed the transfer of heat to the mass of concrete. The compressive and tensile strengths, however, increased with the replacement of up to 20% POFA. The results obtained and the observation made in this study suggest that the substitution of OPC by POFA is beneficial, particularly for prepacked mass concrete where thermal cracking due to extreme heat rise is of great importance

Factors Affecting the Effectiveness of Social Media for Recruitment: An Exploratory Factor Analysis Approach on Private Universities in Bangladesh

Social media are crucial weapons which are used as online recruitment tool at present time.  The study is designed to explore the most crucial factors which affect the effectiveness of social media for recruitment. This paper is basically prepared based on 50 respondents from 10 private universities of Bangladesh to understand the cost and time effectiveness of social media for recruitment. Data used for this study have been collected by using a structured questionnaire of 5 point Likert scale which consists of 15 specific questions. The study is conducted by factor analysis and attained 4 factors including Information Quality, Privacy & Security, Cost & Time and User Friendly that influence the effectiveness of social media for recruitment.  Another statistical tool t-test has been also used to prove the hypothesis. The study also reveals that these four factors are in satisfactory level. From the study concerned people in this arena can get a specific view about the factors that directly influence the effectiveness of social media for recruitment and take corrective actions to improve the present situation. Keywords: Social Media, Social Media Recruitment, Benefits of Social Media Recruitment, Factor Analysis and T-test