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Palm oil industry’s bi-products as coarse aggregate in structural lightweight concrete
Md. Nazmul Huda,Mohd Zamin Jumaat,A. B. M. Saiful Islam,Kh Mahfuz ud Darain,M. Obaydullah,Md. Akter Hosen 사단법인 한국계산역학회 2017 Computers and Concrete, An International Journal Vol.19 No.5
Recent trend is to use the lightweight concrete in the construction industry because it has several advantages over normal weight concrete. The Lightweight concrete can be produced from the industrial waste materials. In South East Asian region, researchers are very keen to use the waste materials such as oil palm shell (OPS) and palm oil clinker (POC) from the palm oil producing industries. Extensive research has been done on lightweight concrete using OPS or POC over the last three decades. In this paper the aggregate properties of OPS and POC are plotted in conjunction with mechanical and structural behavior of OPS concrete (OPSC) and POC concrete (POCC). Recent investigation on the use of crushed OPS shows that OPSC can be produced to medium and high strength concrete. The density of OPSC and POCC is around 20-25% lower than normal weight concrete. Generally, mechanical properties of OPSC and POCC are comparable with other types of lightweight aggregate concrete. It can be concluded from the previous study that OPSC and POCC have the noteworthy potential as a structural lightweight concrete.
A.B.M. Saiful Islam,University of MalayaMohd Zamin Jumaat,Raja Rizwan Hussain,Md. Akter Hosen,Md. Nazmul Huda 사단법인 한국계산역학회 2015 Computers and Concrete, An International Journal Vol.16 No.4
Traditionally, multi-story buildings are designed to provide stiffer structural support to withstand lateral earthquake loading. Introducing flexible elements at the base of a structure and providing sufficient damping is an alternative way to mitigate seismic hazards. These features can be achieved with a device known as an isolator. This paper covers the design of base isolators for multi-story buildings in medium-risk seismicity regions and evaluates the structural responses of such isolators. The well-known tower building for police personnel built in Dhaka, Bangladesh by the Public Works Department (PWD) has been used as a case study to justify the viability of incorporating base isolators. The objective of this research was to establish a simplified model of the building that can be effectively used for dynamic analysis, to evaluate the structural status, and to suggest an alternative option to handle the lateral seismic load. A finite element model was incorporated to understand the structural responses. Rubber-steel bearing (RSB) isolators such as Lead rubber bearing (LRB) and high damping rubber bearing (HDRB) were used in the model to insert an isolator link element in the structural base. The nonlinearities of rubber-steel bearings were considered in detail. Linear static, linear dynamic, and nonlinear dynamic analyses were performed for both fixed-based (FB) and base isolated (BI) buildings considering the earthquake accelerograms, histories, and response spectra of the geological sites. Both the time-domain and frequency-domain approaches were used for dynamic solutions. The results indicated that for existing multi-story buildings, RSB diminishes the muscular amount of structural response compared to conventional non-isolated structures. The device also allows for higher horizontal displacement and greater structural flexibility. The suggested isolation technique is able to mitigate the structural hazard under even strong earthquake vulnerability.
(Shaikh Mizanoor Rahman),(M. Nazmul Huda),(M. Nasir Uddin),(Sharif Akhteruzzaman) 생화학분자생물학회 2002 BMB Reports Vol.35 No.5
The present study explored the short-term effects of dietary conjugated-linoleic acid (CLA) on liver lipid metabolism in starved/refed Otsuka Long Evans Tokushima Fatty (OLETF) rats. Male OLETF rats (12 weeks old) were starved for 24 hours, then refed for 48 hours with either a CLA diet [7.5% CLA and 7.5% Safflower oil (SAF)] or a SAF control diet (15% SAF). The results demonstrated a 30% reduction of hepatic triglyceride (TG) concentration in the CLA group when compared to the control group. Liver cholesterol concentration was also 26% lower in the CLA fed rats. The activity of mitochondrial carnitine palmitoyltransferase, the rate-limiting enzyme of fatty acid oxidation, was moderately elevated by 1.2-fold in the livers of the CLA group when compared to the control. In contrast, phosphatidate phosphohydrolase, the ratelimiting enzyme for TG synthesis, was found to be 20% lower in the livers of the CLA-fed rats. Therefore, dietary CLA evidently lowers liver lipid concentrations through a reduced TG synthesis and enhanced fatty acid oxidation in starved/refed OLETF rats.
Rahman, Shaikh Mizanoor,Huda, M. Nazmul,Uddin, M. Nas,Akhteruzzaman, Sharif Korean Society for Biochemistry and Molecular Biol 2002 Journal of biochemistry and molecular biology Vol.35 No.5
The present study explored the short-term effects of dietary conjugated-linoleic acid (CLA) on liver lipid metabolism in starved/refed Otsuka Long Evans Tokushima Fatty (OLETF) rats. Male OLETF rats (12 weeks old) were starved for 24 hours, then refed for 48 hours with either a CLA diet [7.5% CLA and 7.5% Safflower oil (SAF)] or a SAF control diet (15% SAF). The results demonstrated a 30% reduction of hepatic triglyceride (TG) concentration in the CLA group when compared to the control group. Liver cholesterol concentration was also 26% lower in the CLA fed rats. The activity of mitochondrial carnitine palmitoyltransferase, the rate-limiting enzyme of fatty acid oxidation, was moderately elevated by 1.2-fold in the livers of the CLA group when compared to the control. In contrast, phosphatidate phosphohydrolase, the rate-limiting enzyme for TG synthesis, was found to be 20% lower in the livers of the CLA-fed rats. Therefore, dietary CLA evidently lowers liver lipid concentrations through a reduced TG synthesis and enhanced fatty acid oxidation in starved/refed OLETF rats.
Eliminating concrete cover separation of NSM strengthened beams by CFRP end anchorage
Md. Akter Hosen,Mohd Zamin Jumaat,A. B. M. Saiful Islam,Mohamed Kamruzzaman,Md. Nazmul Huda,Mahmudur Rahman Soeb 국제구조공학회 2015 Structural Engineering and Mechanics, An Int'l Jou Vol.56 No.6
Upgrading or strengthening of existing reinforced concrete (RC) infrastructure is an emerging demand nowadays. Near Surface Mounted (NSM) technique is very promising approach for flexural strengthening of RC members. However, premature failure such as concrete cover separation failure have been a main concern in utilizing this technique. In this study, U-wrap end anchorage with carbon fiber reinforced polymer (CFRP) fabrics is proposed to eliminate the concrete cover separation failure. Experimental programs were conducted to the consequence of U-wrap end anchorage on the flexurally strengthened RC beams with NSM- steel. A total of eight RC rectangular beam specimens were tested. One specimen was kept unstrengthened as a reference; three specimens were strengthened with NSM-steel bars and the remaining four specimens were strengthened with NSM-steel bars and U-wrap end anchorage using CFRP fabrics. A 3D non-linear finite element model (FEM) was developed to simulate the flexural response of the tested specimens. It is revealed that NSM-steel (with and without end-anchors) significantly improved the flexural strength; moreover decreased deflection and strains compared with reference specimen. Furthermore, NSM-steel with end anchorage strengthened specimens revealed the greater flexural strength and improve failure modes (premature to flexure) compared with the NSM-steel without end anchorage specimens. The results also ensured that the U-wrap end anchorage completely eliminate the concrete cover separation failure.