Analysis of Organic Matter in Sediments and Macrozoobenthos From Coastal Waters of Hurun Bay of Lampung

This study was conducted in July 2015 with the aim to observe the macrozoobenthospopulation and organic matter content in the sediment. The samples were collected from HurunBay in Lampung Province with using survey method. Samples were analyzed in the Laboratoryof Water Quality BBPPL Lampung and Chemistry Laboratory, Faculty of Fisheries and MarineSciences University of Riau. The study showed that the organic content in the sediment between22.88 - 54.91%, while the abundance of macrozoobenthos was between 20.29 - 66.67 ind / m2.Macrozoobenthos identified in Hurun Bay 8 species, 3 classes and 2 phylua. From the phylum ofMollusca there were Gastropod i.e. which had 5 species and from the classes of bivalves thestudy also found two species. From the phylum annelid there was one class, Polychaeta and onespecies, i.e. Nereis sp. The relationship between macrozoobenthos and organic content wasexpressed with the equation of Y = 9,411 + 0,6268X that the relationship of organic matter withmacrozoobenthos abundance was weak

Experimental and Numerical Investigation of SUP12 Steel Coil Spring

Coil springs made of spring steel often have high yield strength which enables them to return to their original form after a significant force is applied. Specific application of steel springin automotive is ruled by industrial guideline, for example, Japanese Industrial Standard (JIS), Daewoo Engineering Standard (EDS) and Daihatsu Technical Standards (DTS). This study attempt to investigate the characteristics of a coil spring type used in automotive i.e. SUP12 where the analysis approach was done systematically using experimental and numerical methods. The experimental part was intended to verify the SUP12 springs material properties (spring constant, yield strength and tensile strength) are within standard for spring steels, JIS G 4801(1984). The SUP12 spring underwent tensile testing in accordance to JIS Z 2201(2010). Later, finite element simulation was performed using HYPERWORKS (Ver. 11) software to predict the steel spring under displacement conditions as per specific customer requirement i.e. at full rebound, curb length and full bump. The resulting experimental data indicates that the tested SUP12 passed the minimum requirement as per standard. On the other hand, finite element results show that the spring meets the customer requirement within small deviation. This suggested that the systematic verification by experiment and numerical analysis approach on such spring is practical by spring maker

Fracture mechanisms and failure analysis of carbon fibre/toughened epoxy composites subjected to compressive loading

This study investigates the failure mechanisms of unidirectional (UD) HTS40/977-2 toughened resin composites subjected to longitudinal compressive loading. A possible sequence of failure initiation and propagation was proposed based on SEM and optical microscopy observations of failed specimens. The micrographs revealed that the misaligned fibres failed in two points upon reaching maximum micro-bending deformation and two planes of fracture were created to form a kink band. Therefore, fibre microbuckling and fibre kinking models were implemented to predict the compressive strength of LID HTS40/977-2 composite laminate. The analysis identified several parameters that were responsible for the microbuckling and kinking failure mechanisms. The effects of these parameters on the compressive strength of the LID HTS40/977-2 composite systems were discussed. The predicted compressive strength using a newly developed combined modes model showed a very good agreement to the measured value (c) 2009 Elsevier Ltd. All rights reserve

The Novel Digital Image Correlation Technique in Predicting Behaviour and Failure of Hybrid Composite

This paper presents a technique in measuring deformation occurs on in-plane hybrid composite CFRP/GFRP. The challenging task of extracting mechanical properties of the hybrid composite is assisted with the use of Digital Image Correlation (DIC) technique. DIC is an innovative technique which able to capture full field deformation of tensile deformation. The complex deformation captured for hybrid composite in-plane tensile deformation and behavior using Digital Image Correlation (DIC) under static loading is a new area of study in literature. Generally, hybrid composite consists of more than one reinforcing sections or multiple reinforcing or multiple matrix sections or single reinforcing phase with multiple matrix phases. As a result of a compromise between the materials within the hybrid composite, the deformation and stress analysis are to be evaluated and tailored as each constituent of material carry their own desired mechanical properties according to a performance requirement. It is found in relation of stress-strain relationship of hybrid composite under tensile loading via DIC, the modulus of elasticity is found to record value around 92-97GPa which in theoretical benchmark located in between value of Modulus of Elasticity, E1 for CFRP(120GPa) and GFRP(42GPa) which proves the occurrence of the hybrid effect. It is a new research area in utilizing digital image correlation (DIC) technique on hybrid composite rather than conventional composite in material characterization

Aptness of kenaf powder as a friction modifier in the fabrication of brake friction material by powder metallurgy route

Braking system is one of the important passive safety features for sustaining the vehicle’s speed while driving downhill, to decelerate the motorcycle and completely stop the moving vehicle. Brake friction materials play an important role in resisting the movement of vehicle and composed of four components (binder, reinfored materials, friction modifier materials and filler materials). This work is to investigate the effect of the kenaf powder as a friction modifier on mechanical and tribological properties. Four brake friction material formulations (K, KA, KB and KC) have been prepared through powder metallurgy route. The samples were examined for their porosity, hardness, COF and thicknes loss properties. Sample KA, KB, KC which composed of kenaf powders had a higher COF than sample K, without composed of kenaf powders. Test results show that sample KB which was composed of 10 volume percentage of kenaf powders is the best formulation based on COF and thickness loss results. Thus, it could be concluded that kenaf powders can be used as a friction modifer in brake friction material formulations

The Effects of Surface Curvature on Cartilage Behaviour in Indentation Test: A Finite Element Study

Computational modelling of the behaviour of articular cartilage is important in order to improve the understanding of disease processes such as arthritis, and the suitability of biomaterials in surgical treatment. In previous computational studies, the cartilage surface of axisymmetric models was assumed to be flat in order to evaluate the cartilage behaviour. This assumption was inappropriate since the synovial joint possessed curvature geometrical shape and may contribute to inaccurate results. Therefore, this study aims to examine the effects of the cartilage surface curvature to the cartilage behavior in indentation test using finite element analysis. Axisymmetric biphasic poroelastic finite element models of flat and various cartilage surface radii, including both concave and convex shapes of the curve, were generated to simulate creep indentation test in order to investigate possible effect to the contact stress and pore pressure of the cartilage. Based on the results, the smaller cartilage surface of 10 mm radius produced higher difference of the cartilage behaviour where it generated 39% difference in pore pressure and 6% difference in contact stress, compared to the flat cartilage. This could indicate that the cartilage curvature does affect the cartilage behavior in indentation test particularly the pore pressure of cartilage

A cross-sectional study on level of knowledge and level of attitude towards asthma among the sampled population aged 13 years and above of Rumah Uming and Rumah Cherida, Meradong, from 20th November 2006 to 26th January 2007

Introduction: Asthma is a chronic inflammatory disorder of the airways characterized by wheezing, breathlessness, chest tightness and cough. Asthma affects people of all ages. In Malaysia, asthma was among the commonest conditions that accounted for outpatient department attendance. Asthma is not curable, yet an asthmatic patient can live a normal life ifit is well-controlled. Objectives: The objective of this study is to study the level of knowledge and level of attitude towards asthma among the sampled population aged 13 years and above in Rumah Uming and Rumah Cherida from 20th November 2006 to 26th January 2007. Methodology: A cross-sectional study on level of knowledge and level of attitude towards asthma was carried out. The sample size of 90 respondents was chosen using a simple random sampling method. Data collection was done by means of interview-guided questionnaire, and all collected data was entered and analysed using SPSS software version 13. The statistical tests that were used include Pearson correlation test, chi-square test, independent sample t-test, ANOV A test, Spearman rho test, Mann-Whitney U test and Kruskal-Wallis test. Results: The main source of information regarding asthma was obtained from mass media. The study showed more than half of the respondents had poor level of knowledge in terms of general knowledge and signs and symptoms (62.2%), risk factor and triggering factor (55.6%), and treatment and prevention of asthma (60.0%). However, 56.7% of respondents had good knowledge about complications of asthma. There was a significant relationship between total level of knowledge with gender (p = 0.034), household income (p = 0.018), and personal and family history of asthma (p = 0.008). Females, higher income group and respondents with personal and family history of asthma showed better score of knowledge. Most of the respondents had good attitude in terms of seeking knowledge (65.6%) and prevention of asthma (53.3%), however 55.6% showed poor attitude in terms of the treatment of asthma. Significant association was found between total level of attitude and level of education (p = 0.042). There was also a positive relationship between the total level of knowledge and the total level of attitude towards asthma among the respondents (p = 0.023). Conclusion: The study revealed a significantly higher level of knowledge among the respondents who were female, with higher household income and with personal and family history of asthma