We designed a high sensitivity optical biosensor based on Mach-zehnder Interferometer (MZI) by covering the silica waveguide with single atomic layer of graphene material. Graphene was applied to the arm of MZI in certain length. The upper arm was set an important key as the reference signal. The sensor sensitivity was determined mathematically from the power difference launched at the output ports. Our results shows novel optical absorption of hybrid waveguide applied in MZI arm. The presence of sample, which induces the effective index of the hybrid waveguide, significantly changes the phase of light propagation and the power ratio at the output ports which determines the sensitivity. Finally, we showed the effect of the distance between the graphene to the core and the length of graphene on waveguide of MZI.
Faculty of Science and Technology, State Islamic University of Riau, Pekanbaru 28282, Indonesia
Lately, a climatic change has affected the uncertain occurrence of the rain process that implicates several difficulties in estimating flood disaster. The matter will certainly give the big problem to urban areas. Two stochastic-rain models which use the hourly rainfall data, Neyman-Scott Rectangular Pulse (NSRP) and Bartlett-Lewis Rectangular Pulse (BLRP), are a better way to identify the pattern of the rain events. Five rain characteristics represented by NSRP model’s parameter and six characteristics represented by BLRP model’s parameter will be used in identifying the rain pattern which is represented by the some rain statistics such as the probability and average of the hourly and daily rainfall. Two statistical rain models will predict the statistical value. This research using the data on 39-year rainfall per hour (1970-2008) from Alorsetar rain station has showed. It has been proved that some statistic models such as the statistical values which are generated by both models are very similar to those of observation statistics or statistics values which are generated from data.
Department of Mathematics, Faculty of Science and Technology, State Islamic University of Sultan Syarif Kasin, Riau, Indonesia
Turn-milling is a machining method with a system of merging turning and milling operations, which the workpieces and cutting tool perform rotary motion synchronously to optimize the disposal process of chip materials. Development of turn-milling can be done on the lathe and milling conventional machining. The purpose of this study is to modify a conventional lathe with a stationary cutting tool and use a single cutting edge into a rotary tool using 4 (four) cutting sides (multy point cutting). In the manufacture and installation of rotary tool on conventional lathes, tools are made portable and can work on tangential, orthogonal and co-axial turn-milling systems. For the orthogonal and co-axial operating system of the turn-milling are divided into up and down operating systems. In this research the phenomenon of material disposal process of the work-piece surface was investigated. In the process of turn-milling test, the chip was removed automatically as the turn of the cutting edge of the endmill cutting tool. The high decreasing of cutting knife rotation during testing was resulted a space during the process of disposal of material. Sequence, it was occurred pores or cavities in the work-piece.
Laboratory of Technology Production, Department of Mechanical Engineering, Faculty of Engineering, Universitas Riau, Indonesia
