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Margaretta D.O.,Bandung Institute of Technology | Lestari M.S.,Bandung Institute of Technology | Nuryadin B.W.,State Islamic University Sunan Gunung Djati | Abdullah M.,Bandung Institute of Technology
European Physical Journal B | Year: 2016

We introduce a new and general criterion for melting as an alternative to the commonly used Lindemann criterion. Nanostructures are modeled using a zipper model and the melting process is assumed to start from the outer layer and develop towards the center layer. Melting occurs when the logarithm of the partition function per number of layers is zero. The equation shows good consistency with experimental data for the melting of thin films, nanoparticles, and nanowires. We also introduce a degree-of-freedom parameter which seems to be universal for most metals. © 2016, EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.


Salleh Z.,University of Malaysia, Terengganu | Mada Sanjaya W.S.,University of Malaysia, Terengganu | Mada Sanjaya W.S.,State Islamic University Sunan Gunung Djati | Mamat M.,University of Malaysia, Terengganu | Noor N.M.M.,University of Malaysia, Terengganu
Journal of Sustainability Science and Management | Year: 2011

In this paper, we study an ecological model with a tritrophic food chain composed of a classical Lotka-Volterra functional response for prey and predator, and a Michaelis-Menten-type functional response for predator and top predator. There are two equilibrium points of the system. In the parameter space, there are passages from instability to stability, which are called Hopf bifurcation points. For the first equilibrium point, it is possible to find bifurcation points analytically and to prove that the system has periodic solutions around these points. Furthermore the dynamical behaviours of this model are investigated. The dynamical behaviour is found to be very sensitive to parameter values as well as the parameters of the practical life. Computer simulations are carried out to explain the analytical findings. © Universiti Malaysia Terengganu Publisher.


Sunaryo M.S.W.,State Islamic University Sunan Gunung Djati | Salleh Z.,University of Malaysia, Terengganu | Mamat M.,University of Malaysia, Terengganu
International Journal of Pure and Applied Mathematics | Year: 2013

In this paper, we study ecological model with a tritrophic food chain composed of a classical Lotka-Volterra functional response for prey and predator, and a Holling type-III functional response for predator and superpredator. There are two equilibrium points of the system. In the parameter space, there are passages from instability to stability, which are called Hopf bifurcation points. For the first equilibrium point, it is possible to find bifurcation points analytically and to prove that the system has periodic solutions around these points. Furthermore the dynamical behavior of this models are investigated. The dynamical behavior is found to be very sensitive to parameter values as well as the parameters of the practical life. Computer simulations are carried out to explain the analytical findings. © 2013 Academic Publications, Ltd.


Eka Putra R.,Bandung Institute of Technology | Kinasih I.,State Islamic University Sunan Gunung Djati
Pakistan Journal of Biological Sciences | Year: 2013

Tomato (Lycopersicon esculentum Mill.) is considered as one of major agricultural commodity of Indonesia farming. However, monthly production is unstable due to lack of pollination services. Common pollinator agent of tomatoes is bumblebees which is unsuitable for tropical climate of Indonesia and the possibility of alteration of local wild plant interaction with their pollinator. Indonesia is rich with wild bees and some of the species already domesticated for years with prospect as pollinating agent for tomatoes. This research aimed to assess the efficiency of local honey bee (Apis cerana L.) and stingless bee (Trigona iridipennis), as pollinator of tomato. During this research, total visitation rate and total numbers of pollinated flowers by honey bee and stingless bee were compared between them with bagged flowers as control. Total fruit production, average weight and size also measured in order to correlated pollination efficiency with quantity and quality of fruit produced. Result of this research showed that A. cerana has slightly higher rate of visitation (p>0.05) and significantly shorter handling time (p<0.05) than T. iridipennis due to their larger colony demand and low reward provide by tomato flowers. However, honey bee pollinated tomato flowers more efficient pollinator than stingless bee (80.3 and 70.2% efficiency, respectively; p<0.05) even though the average weight and size of tomatoes were similar (p>0.05). Based on the results, it is concluded that the use of Apis cerana and Trigona spp., for pollinating tomatoes in tropical climates could be an alternative to the use of non-native Apis mettifera and bumblebees (Bombus spp.). However, more researches are needed to evaluate the cost/benefit on large-scale farming and greenhouse pollination using both bees against other bee species and pollination methods. © 2014 Asian Network for Scientific Information.


Mamat M.,University of Malaysia, Terengganu | Sanjaya W.S.M.,University of Malaysia, Terengganu | Sanjaya W.S.M.,State Islamic University Sunan Gunung Djati | Salleh Z.,University of Malaysia, Terengganu | Ahmad M.F.,University of Malaysia, Terengganu
Journal of Sustainability Science and Management | Year: 2011

In this paper, we study an ecological model with a tritrophic food chain with a classical Lotka-Volterra functional response. There are three equilibrium points of the system. In the parameter space, there are passages from instability to stability, which are called Hopf bifurcation points. For the equilibrium point, it is possible to find bifurcation points analytically and to prove that the system has periodic solutions around these points. Furthermore, the dynamical behaviours of this model are investigated. It has been found that the extinction of the predator depends on the prey-predator parameter in the equation. The dynamical behaviour is found to be very sensitive to the parameter values and the initial condition as well as the parameters of the practical life. Computer simulations are carried out to explain the analytical findings. © Universiti Malaysia Terengganu Publisher.

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