University of Malaya

About: University of Malaya is a education organization based out in Kuala Lumpur, Malaysia. It is known for research contribution in the topics: Population & Fiber laser. The organization has 25087 authors who have published 51491 publications receiving 1036791 citations. The organization is also known as: UM & Universiti Malaya.

Measurement of the differential cross section for top quark pair production in pp collisions at √s=8 TeV

Abstract: The normalized differential cross section for top quark pair (tt) production is measured in pp collisions at a centre-of-mass energy of 8TeV at the CERN LHC using the CMS detector in data corresponding to an integrated luminosity of 19.7fb^(−1). The measurements are performed in the lepton+jets (e/μ +jets) and in the dilepton (e^+e^−, μ^+μ^−, and e^±μ^∓) decay channels. The tt cross section is measured as a function of the kinematic properties of the charged leptons, the jets associated to b quarks, the top quarks, and the tt system. The data are compared with several predictions from perturbative quantum chromodynamic up to approximate next-to-next-to-leading-order precision. No significant deviations are observed relative to the standard model predictions.

Applications of Lignocellulosic Fibers and Lignin in Bioplastics: A Review

Abstract: Lignocellulosic fibers and lignin are two of the most important natural bioresources in the world. They show tremendous potential to decrease energy utilization/pollution and improve biodegradability by replacing synthetic fibers in bioplastics. The compatibility between the fiber-matrix plays an important part in the properties of the bioplastics. The improvement of lignocellulosic fiber properties by most surface treatments generally removes lignin. Due to the environmental pollution and high cost of cellulose modification, focus has been directed toward the use of lignocellulosic fibers in bioplastics. In addition, lignin-reinforced bioplastics are fabricated with varying success. These applications confirm there is no need to remove lignin from lignocellulosic fibers when preparing the bioplastics from a technical point of view. In this review, characterizations of lignocellulosic fibers and lignin related to their applications in bioplastics are covered. Then, we generalize the developments and problems of lignin-reinforced bioplastics and modification of lignin to improve the interaction of lignin-matrix. As for lignocellulosic fiber-reinforced bioplastics, we place importance on the low compatibility of the lignocellulosic fiber–matrix. The applications of lignin-containing cellulose and lignocellulosic fibers without delignification in the bioplastics are reviewed. A comparison between lignocellulosic fibers and lignin in the bioplastics is given.

Feasibility of diesel–biodiesel–ethanol/bioethanol blend as existing CI engine fuel: An assessment of properties, material compatibility, safety and combustion

Abstract: The global fossil fuel crisis and emission problems lead to investigations on alternative fuels. In this quest, a successful finding is the partial substitution of diesel with ethanol/bioethanol rather than completely replacing it. These blends of diesel and ethanol/bioethanol can be used in the existing CI engines without any major modifications and the most significant result of using this blend is the lower emission with almost the same performance as of diesel fuel alone. Two major drawbacks of using this blend are low miscibility of ethanol/bioethanol in diesel and low temperature instability of produced blend. However, biodiesel can be successfully added to prevent the phase separation of diesel–ethanol/bioethanol blend. Thus, this blend becomes stable even at lower temperatures and more amount of ethanol/bioethanol can be added to them. It is found that a maximum of 25% biodiesel and 5% of ethanol/bioethanol can be added to the diesel fuel effectively. Adding ethanol/bioethanol to diesel fuel alters the properties of the blend, which does not meet some of the standards. Biodiesel addition to this blend helps in regaining the fuel properties to the standard values and thus the blend can be efficiently used in the existing diesel engines. From the review, it can be said that, the use of diesel–biodiesel–ethanol/bioethanol blend can minimize the use of diesel fuel by approximately 25–30%.

Conservation value of degraded habitats for forest birds in southern Peninsular Malaysia

Abstract: Clearance of tropical forest for agricultural purposes is generally assumed to seriously threaten the survival of forest species. In this study, we quantified the conservation value, for forest bird species, of three degraded habitat types in Peninsular Malaysia, namely rubber tree plantations, oil palm plantations, and open areas. We surveyed these degraded habitats using point counts to estimate their forest bird species richness and abundance. We assessed whether richness, abundance, and activities of different avian dietary groups (i.e. insectivores and frugivores) varied among the habitats. We identified the critical habitat elements that accounted for the distribution of forest avifauna in these degraded habitats. Our results showed that these habitats harboured a moderate fraction of forest avifauna (approximately 46 ‐76 species) and their functions were complementary (i.e. rubber tree plantations for moving; open habitats for perching; shrubs in oil palm plantations for foraging). In terms of species richness and abundance, rubber tree plantations were more important than oil palm plantations and open habitats. The relatively high species richness of this agricultural landscape was partly due to the contiguity of our study areas with extensive forest areas. Forecasts of forest-species presence under various canopy cover scenarios suggest that leaving isolated trees among non-arboreal crops could greatly attract relatively tolerant species that require tree canopy. The conservation value of degraded habitats in agricultural landscapes seems to depend on factors such as the type of crops planted and distance to primary forest remnants.