pertanika journal of science and technology 

About: pertanika journal of science and technology is an academic journal published by University of Putra Malaysia. The journal publishes majorly in the area(s): Materials science & Computer science. It has an ISSN identifier of 0128-7680. Over the lifetime, 787 publications have been published receiving 1962 citations.

Feature selection methods: case of filter and wrapper approaches for maximising classification accuracy

Abstract: Feature selection has been widely applied in many areas such as classification of spam emails, cancer cells, fraudulent claims, credit risk, text categorisation and DNA microarray analysis. Classification involves building predictive models to predict the target variable based on several input variables (features). This study compares filter and wrapper feature selection methods to maximise the classifier accuracy. The logistic regression was used as a classifier while the performance of the feature selection methods was based on the classification accuracy, Akaike information criteria (AIC), Bayesian information criteria (BIC), Area Under Receiver operator curve (AUC), as well as sensitivity and specificity of the classifier. The simulation study involves generating data for continuous features and one binary dependent variable for different sample sizes. The filter methods used are correlation based feature selection and information gain, while the wrapper methods are sequential forward and sequential backward elimination. The simulation was carried out using R, an open-source programming language. Simulation results showed that the wrapper method (sequential forward selection and sequential backward elimination) methods were better than the filter method in selecting the correct features.

Properties of laterite brick reinforced with oil palm empty fruit bunch fibres

Abstract: The development of a new, low-cost building material that is composed of non-fired, pressed laterite bricks incorporating oil palm empty fruit bunches (OPEFB) fibre was investigated in this study. The main aim of this research was to study the physical and mechanical properties of laterite brick reinforced with OPEFB fibre, including dimensions, weight, density, water absorption and compressive strength. The tests were carried out according to BS 3921:1985 for water absorption and compressive strength tests. The mix proportion of the control bricks was 70% soil, 24% sand, and 6% cement. Meanwhile, the OPEFB fibre contents ranged from 1% to 5% by weight of cement. The specimens were taken from a total of 120 bricks. The findings withdrawn from this research were: firstly, the density of laterite bricks was decreased with the increase in the OPEFB fibre content of the bricks. Secondly, it was found that the addition of the OPEFB fibres improved the compressive strength of the bricks, and the maximum compressive strength determined in this study for bricks was with 3% fibre content. Finally, the water absorption results indicated a small increase in water absorption with the increase in the OPEFB fibre content in laterite bricks.

A Review of Farm Tractor Overturning Accidents and Safety

Abstract: Tractor rollover occurs when a tractor tips sideways or backwards and overturns, potentially crushing the operator. Rollovers are typically considered to occur more frequently during a sharp turn at a high speed on sloping terrains, although data show that rollovers do occur on flat land after hitting obstacles or through inappropriate use and hitching of implements. It is important to highlight that tractor overturns are the major cause of death in farm operations. The overturns are as a result of interactions between the tractor operator, the tractor and the environment. A review of the relevant literature reveals that more than 800 people are killed each year in tractor accidents, and for every person killed, at least 40 others are injured. This paper focuses on tractor overturns because they account for more than half of all the tractor-related deaths. In addition, farm tractor operational safety principles are also highlighted.

A review: Fibres, polymer matrices and composites

Abstract: The growing interest, environmental consciousness and high performance demands on engineering have led to extensive research and development of new and improved materials. Among the most commonly used natural fibres are kenaf, oil palm, sugar palm, pineapple leaf fibre, flax, hemp, sisal, coir and jute. These fibres are used to reinforce thermoplastic polymer matrices such as polystyrene (PS), polypropylene (PP), polyethylene (PE) and polyvinyl chloride (PVC). Meanwhile, phenolic, unsaturated polyester vinyl ester and epoxy resin are for thermosetting polymer matrices. The objective of this paper is to solicit works that cover major class of natural fibres, thermosetting polymers matrices, which detail about unsaturated polyester resin and hybrid biocomposites industry.

Factors affecting the cold flow behaviour of biodiesel and methods for improvement - a review.

Abstract: Biodiesel is an attractive renewable energy source, which is suitable as a substitute to the non renewable petroleum diesel. However, it is plagued by its relatively bad cold flow behaviour. In this review, the factors affecting the cold flow of biodiesel, vis-a-vis the contradicting requirement of good cold flow and good ignition properties, are discussed. Fuel filter plugging, and crystallization of biodiesel are considered, together with the cold flow properties such as Pour Point (PP), Cloud Point (CP), Cold Filter Plugging Point (CFPP) and Low Temperature Filterability Test (LTFT). In addition, various methods used to improve the cold flow of biodiesel are also presented, with a special emphasis laid on the effects of these methods in reducing the Cloud Point. Strategies to improve cold flow, and yet maintaining the good ignition quality of biodiesel, are also proposed. As far as the cold flow of biodiesel is concerned, desirable attributes of its esters are short, unsaturated and branched carbon chains. However, these desirable attributes present opposing properties in terms of ignition quality and oxidation stability. This is because esters with short, unsaturated and branched carbon chains possess very good cold flow but poor ignition quality and oxidation stability. The target is therefore to produce biodiesel with good cold flow, sufficient ignition quality, and good oxidation stability. This target proves to be quite difficult and is a major problem in biodiesel research. New frontiers in this research might be the design of the new cold flow improvers that is similar to those used in the petroleum diesel but is tailored for biodiesel. Genetic modifications of the existing feedstock are also desirable but the food uses of this particular feedstock should always be taken into consideration.