Abstract For the design and operation of a floating bridge, the understanding of its hydroelastic behavior in waves is of great importance. This paper investigated the hydroelastic performances of a ribbon bridge under wave action. A... more
Abstract For the design and operation of a floating bridge, the understanding of its hydroelastic behavior in waves is of great importance. This paper investigated the hydroelastic performances of a ribbon bridge under wave action. A brief introduction on ...
Abstrak—Telah dilakukan percobaan berjudul Cincin Newton yang berprinsip pada sifat interferensi cahaya dan bertujuan untuk memelajari eristiwa interferensi pada percobaan Cincin Newton, menjelaskan fungsi-fungsi alat pada Cincin Newton,... more
Abstrak—Telah dilakukan percobaan berjudul Cincin Newton yang berprinsip pada sifat interferensi cahaya dan bertujuan untuk memelajari eristiwa interferensi pada percobaan Cincin Newton, menjelaskan fungsi-fungsi alat pada Cincin Newton, Mengukur panjang gelombang dari lampu halogen dengan menggunakan metode Cincin Newton, serta mencari keseksamaan panjang gelombang yang terukur dengan panjang gelombang yang sebenarnya. Dari percobaan ini, dapat ditarik kesimpulan bahwa Interferensi pada Cincin Newton terbentuk dari satu celah. Dalam Cincin Newton tersebut, beberapa macam alat, seperti lensa okuler yang berfungsi untuk melihat objek dari mata pengamat. Terdapat pula lensa objektif yang berfungsi untuk mengamati objek dengan perbesaran tertentu. Cahaya Halogen yang berfungsi sebagai sumber cahaya, Mikrometer sekrup yang berfungsi pengukur jari-jari yang didapat dari pengamatan. Selain itu terdapat reflektor yang berfungsi untuk memantulkan sinar halogen agar sampai ke lensa bikonfeks secara sempurna. Lensa bikonfeks berfungsi untuk mengumpulkan cahaya dan membentuk pola terang gelap dengan gelas kaca yang ada di bawahnya. Panjang gelombang untuk orde di atas diameter adalah 0.00027mm, sedangkan di bawah diameter adalah 0.00048mm, dan nilai error yang didapatkan untuk pengukuran di atas dimeter adalah 58.25% dan di bawah diameter adalah 27.06%.
The actin cytoskeleton is a primary determinant of cell shape and motility. Studies on actin regulatory proteins are now coupled with studies of the signal transduction that directs actin cytoskeleton reorganization, and we have gained... more
The actin cytoskeleton is a primary determinant of cell shape and motility. Studies on actin regulatory proteins are now coupled with studies of the signal transduction that directs actin cytoskeleton reorganization, and we have gained insights into how external stimuli such as chemoattractants drive changes in actin cytoskeleton. Chemoattractants regulate actin regulatory proteins such as the Arp2⧸3 complex through WASP family proteins, ADF⧸cofilin downstream of LIM-kinase, and various other phosphoinositide-dependent or -independent pathways. Through branching of actin filaments, Arp2⧸3 complex-dependent actin polymerization is suffcient to generate the force necessary for protrusion.
The role of mangrove trees in reducing the tsunami waves during the tragedy of Andaman tsunami occurred on December 26, 2004, has been credited and these indirectly raise awareness about the role of mangroves forest as a natural... more
The role of mangrove trees in reducing the tsunami waves during the tragedy of Andaman tsunami occurred on December 26, 2004, has been credited and these indirectly raise awareness about the role of mangroves forest as a natural breakwater on the beach. This paper will focus on the mangrove trees from Avicennia and Rhizophora species in order to identify the methods of breaking wave energy that has been carried out by the mangrove roots and stems. Analysis of the mangrove roots coordination pattern had been conducted by gathering data at study site located at Kemaman, Terengganu and the data had been plotted in Gambit software for simulation purpose in Fluent Inc software. Hence, the simulation result showed that the ratio of wave height and velocity reduction may vary depending on factors such as the species of the mangrove trees and density of the roots that grow around the tree. Consequently, the study will be examining the waveform that is mitigated by the both species Avicennia...
The effects of waves occurring on a falling condensate film on heat transfer have been studied by direct computer simulation. The time-dependent Navier-Stokes and energy equations, as well as the Poisson equation for pressure, have been... more
The effects of waves occurring on a falling condensate film on heat transfer have been studied by direct computer simulation. The time-dependent Navier-Stokes and energy equations, as well as the Poisson equation for pressure, have been solved for a ...
The world is heavily dependent on fossil fuels since most of its energy requirements are fulfilled by conventional methods of burning these fuels. The energy demand is increasing by day with growing population. The energy production by... more
The world is heavily dependent on fossil fuels since most of its energy requirements are fulfilled by conventional methods of burning these fuels. The energy demand is increasing by day with growing population. The energy production by fossil fuels is devastating the environment and survival of life on globe is endangered. The renewal energy technologies are vital to ensure future energy sustenance and environmental issues. Ocean is a vast resource of renewable energy. The technology today makes it possible to extract energy from tides. The growing interest in exploring tidal current technologies has compelling reasons such as security and diversity of supply, intermittent but predictable and limited social and environmental impacts. The purpose of this study is to present a comprehensive review of tidal current technologies to harness ocean energy. The ocean energy resources are presented. The author discusses tidal energy technologies. The tidal current turbines are discussed in d...
Abstract: The renewal energy technologies are increasingly popular to ensure future energy sustenance and address environmental issues. The tides are enormous and consistent untapped resource of renewable energy. The growing interest in... more
Abstract: The renewal energy technologies are increasingly popular to ensure future energy sustenance and address environmental issues. The tides are enormous and consistent untapped resource of renewable energy. The growing interest in exploring tidal energy has compelling reasons such as security and diversity of supply, intermittent but predictable and limited social and environmental impacts. The tidal energy industry is undergoing an increasing shift towards diffuser augmented turbines. The reason is the higher power ...
Vehicular mobile communications are attracting much attention in wireless communications field. In this paper a new routing protocol for the reduction of interference level during mobile transmissions in VANET environment is proposed,... more
Vehicular mobile communications are attracting much attention in wireless communications field. In this paper a new routing protocol for the reduction of interference level during mobile transmissions in VANET environment is proposed, considering the availability of different channels in the DSRC spectrum. The attention is mainly focused on the routing level of VANET and we propose an interference aware routing scheme for multi-radio vehicular networks based on a new metric, for the maximization of the average SIR level of the connection between source and destination. The proposed idea has been integrated with the AODV routing protocol to design an enhanced Dynamic-Frequency-Interference-Aware-AODV (DFIA-AODV). The proposed idea has been tested and significant performance enhancements were obtained.
The world is heavily dependent on fossil fuels since most of its energy requirements are fulfilled by conventional methods of burning these fuels. The energy demand is increasing by day with growing population. The energy production by... more
The world is heavily dependent on fossil fuels since most of its energy requirements are fulfilled by conventional methods of burning these fuels. The energy demand is increasing by day with growing population. The energy production by fossil fuels is devastating the environment and survival of life on globe is endangered. The renewal energy technologies are vital to ensure future energy sustenance and environmental issues. Ocean is a vast resource of renewable energy. The technology today makes it possible to extract energy from tides. The growing interest in exploring tidal current technologies has compelling reasons such as security and diversity of supply, intermittent but predictable and limited social and environmental impacts. The purpose of this study is to present a comprehensive review of tidal current technologies to harness ocean energy. The ocean energy resources are presented. The author discusses tidal energy technologies. The tidal current turbines are discussed in detail. The author reviews today’s popular tidal current technologies. The present status of ocean energy development is also reported.
Researchers and engineers around the globe are striving to improve green energy technologies. Among green energy technologies, diffuser augmented tidal turbines are attracting focus due to enormous potential for producing energy. The... more
Researchers and engineers around the globe are striving to improve green energy technologies. Among green energy technologies, diffuser augmented tidal turbines are attracting focus due to enormous potential for producing energy. The power output by a tidal turbine is directly proportional to the cube of velocity of incoming fluid flow. Thus, even a minor increase in velocity considerably increases the power output. The diffuser helps accelerate the velocity of incoming fluid flow. Hence, the efficiency of the turbine is significantly increased by using a diffuser. It is challenging to accelerate the incoming flow by a diffuser due to its shape, geometry and fabrication limitations. The diffuser design requires great deal of innovation and time investment. The research community is investing considerable time and financial resources in this arena. However, limited research results are available for diffuser augmented tidal turbines due to their emerging nature, large and costly research & development setup, startup cost and proprietary issues. The purpose of this paper is to present the numerical simulation of 2D model of diffuser for tidal turbine. Numerical simulation results of velocity profile for fifteen models with different mesh sizes is presented in detail. The effect of mesh density on coefficient of velocity is discussed. Predicted results are then compared to experimental results and found in reasonable agreement. The research is essential for utilizing CFD tools for diffuser design for tidal turbine.
In this article, we show the results of a qualitative exploratory researching whose objective was identify and investigate occurrence of representation and mental models (Johnson-Laird, 1983), used for students in the second grade of the... more
In this article, we show the results of a qualitative exploratory researching whose objective was identify and investigate occurrence of representation and mental models (Johnson-Laird, 1983), used for students in the second grade of the high school when asked them to explain, according their perceptions, the production and propagation of waves. The results demonstrate use built analogical representation or their daily perceptions. Include meaning influenced to the ambient and relation with it observed in the answers and illustrations elaborate to the students to explain the waves known by them.
Satellite communication systems play an important role in the deployment of a global communication infrastructure, and the increasing demand for frequency bands with large bandwidth availability to satisfy satellite communications... more
Satellite communication systems play an important role in the deployment of a global communication infrastructure, and the increasing demand for frequency bands with large bandwidth availability to satisfy satellite communications applications requirements makes the exploration of higher and higher frequency ranges of a vital importance. In this paper, an introduction to the WAVE (W-Band Analysis and VErification) mission is presented, in addition to a general overview of the payload architecture and the related perspective applications and services. WAVE is a new project proposed for the Italian Space Agency (ASI) to design and develop a W-band geostationary payload with the aim of performing the experimental studies of the W-band channel and possible utilization in satellite data communications.
Recientes esfuerzos de investigación de la academia, la industria automotriz y el sector gubernamental de transporte señalan a los sistemas de transporte inteligente (STI) como la tecnología clave tanto en el mejoramiento de la seguridad... more
Recientes esfuerzos de investigación de la academia, la industria automotriz y el sector gubernamental de transporte señalan a los sistemas de transporte inteligente (STI) como la tecnología clave tanto en el mejoramiento de la seguridad en las carreteras, como en la eficiencia en el tráfico y el confort al conducir. Las redes vehiculares ad hoc (VANET) tienen un gran potencial para generar aplicaciones dirigidas a aumentar la seguridad en el tráfico. La interacción entre los vehículos y la infraestructura permite la comunicación en tiempo real, lo que a su vez permite proveer información a los conductores en situaciones peligrosas y evitar accidentes. Este artículo provee una visión general de las redes vehiculares Ad-hoc, describe sus conceptos fundamentales, los estándares de comunicación y las aplicaciones vehiculares, y presenta además, una evaluación de simuladores VANET.
The wave-induced dynamic load is one of the most important excitations to be dealt with in the design of offshore structures and the platforms. In order to perform a reliable design of an offshore structure, it is important to obtain an... more
The wave-induced dynamic load is one of the most important excitations to be dealt with in the design of offshore structures and the platforms. In order to perform a reliable design of an offshore structure, it is important to obtain an exact evaluation of its dynamic response to wave load but also to examine the ways of reducing the response. The work analyzed the effects of wave load on periodic support of isolation system of jacket offshore platform. The platform considered herein as an example to examine the effectiveness of the proposed vibration control strategy for offshore structures. In this section, a parametric study for the jacket offshore platform with installation of the periodic support to enhance isolation system due to its attenuations ability over broad frequencies and the effects of wave load on offshore jacket platforms installed with energy dissipation devices such as periodic support were presented. The offshore jacket platforms are modeled as multi-degrees-of-freedom and the general equation for fluid forces acting on a cylinder, considering the relative motion of the body in the fluid as per the Morison's equation was applied to form the basis of modeling of the wave load and supports. The analyzes of the effects of wave load on the offshore platform especially with periodic support was considered due to its attenuations over broad frequencies. It could be realized from the result that increase in waves load varies the increase in frequency domain of the system which enhances subjection to vibration.
[1] A regional ocean circulation model (ROMS) is used to simulate the Chinese land-derived sediment transport in the Bohai Sea, Yellow Sea, and East China Sea (BYECS). The model includes the effect of currents, tides, and waves on the... more
[1] A regional ocean circulation model (ROMS) is used to simulate the Chinese land-derived sediment transport in the Bohai Sea, Yellow Sea, and East China Sea (BYECS). The model includes the effect of currents, tides, and waves on the sediment transport and is used to study the pathway and dynamic mechanisms of the fine-grain sediment transport from the Huanghe River (Yellow River), the Old Huanghe Delta, and the Changjiang River (Yangtze River) in the BYECS. The seasonal variability of the sediment transport in the BYECS and the sources of the Yellow Sea Trough mud patch, the mud patch southwest of Cheju Island, the mud patch offshore from the Zhejiang and Fujian provinces and the Okinawa Trough mud patch are discussed. The results show that the Huanghe River sediment can be transported to the Yellow Sea Trough, but little makes it to the outer shelf while the Old Huanghe Delta sediment is mainly transported to the Yellow Sea Trough. Most of the sediment from the Changjiang River m...
