Finite Element Simulation of a Steady-State Stress Distribution in a Four Stroke Compressed Natural Gas-Direct Injection Engine Cylinder Head

The main aim of this work is to predict the design performance based on the stress/strain and thermal stress behaviour of cylinder head under various operating conditions. The effects of engine operating conditions such as combustion gas temperature and maximum internal pressure, components initial temperature and engine speed on the stress and thermal stress behaviour of the cylinder head have been analyzed. The analysis was carried out using a finite element analysis (FEA) software package, MSC.NASTRAN which is use to simulate and predict the von-Mises stress and strain pattern and thermal distribution of the cylinder head structure during the combustion process in the engine and the geometry modelling was carried out using a popular computeraided engineering tool, CATIA V5. The result can be used to determine the quality of the design as well as identify areas which require further improvement. In this investigation, structural analyses of the cylinder head highlight several areas of interest. The maximum stress is found not exceeding the material strength of cylinder head, and thus the basic design criteria, namely no yielding and no structural failure under firing load case, can be satisfied. In addition, the effect of thermal stress/strain provides a good indication on structural integrity and reliability of the cylinder head, which can be improved in the early stages of design. This steadystate finite element method (FEM) stress analysis can play a very effective role in the rapid prototyping of the cylinder head

Baru-baru ini Gustav Grob (1996) Mengingatkan Lagi Prediksi Club Of Rome di Awal Tahun 1970-an Bahwa Bahan Bakar Fossil, yang Sifatnya Meneemarkan Lingkungan, dan Tak Terbarukan Kian Berkurang Keberadaannya dan dalam Waktu Dekat Harus Diganti dengan Sumber Energi Terbarukan yang Lebih Bersahabat dengan Lingkungan Seperti Sumber-sumber Energi Surya, Biomassa, Angin, Hidro, Dll. Ketergantungan Kita Atas Bahan Bakar Fosil Mungkin Akan Berlanjut Sampai Beberapa Dekade Lagi Tetapi dalam Jumlah Yang

Baru-baru ini Gustav Grob (1996) mengingatkan lagi prediksi Club of Rome di awal tahun 1970-an bahwa bahan bakar fossil, yang sifatnya meneemarkan lingkungan, dan tak terbarukan kian berkurang keberadaannya dan dalam waktu dekat harus diganti dengan sumber energi terbarukan yang lebih bersahabat dengan lingkungan seperti sumber-sumber energi surya, biomassa, angin, hidro, dll. Ketergantungan kita atas bahan bakar fosil mungkin akan berlanjut sampai beberapa dekade lagi tetapi dalam jumlah yang jauh lebih kecil dari apa yang di konsumsikan sebelum tahun 2000 seperti terlihat pada Gambar 1 (Grob, 1996

Beaconless Packet Forwarding Approach for Vehicular Urban Environment

Existing wireless technologies provide communication and information services to all fields of life. The one of the emerging and popular field is vehicular ad hoc networks, with its unique characteristics and highly mobile environment. Different types of routing protocols have been proposed to address the routing issues in network and one of the most efficient types is geographical routing. In this type of protocols, the beacon messages are using to update the node locations and positions. However, these protoocls have been suffered with high channel congestion issue in the network. To this end, we propose a beaconless packet forwarding strategy based on modified handshake messages mechanism. The protocol uses some realistic metrics to select the next forwarder node such as forward progresss and link quality. The protocol performance is evaluated with existing beacon and beaconless geographical routing protocols. The simulation results showed the better performance of the proposed protocol in terms of packet delay and data delivery ratio in realistic wireless channel conditions

Luminescent Polymer Electrolyte Composites Using Silica Coated-Y2O3:Eu as Fillers

Luminescent polymer electrolyte composites composed of silica coated Y2O3:Eu in polyethylene glycol (PEG) matrix has been produced by initially synthesizing silica coated Y2O3:Eu and mixing with polyethylene glycol in a lithium salt solution. High luminescence intensity at round 600 nm contributed by electron transitions in Eu3+ (5D0 → 7F0, 5D0 → 7F1, and 5D0 → 7F3 transitions) were observed. The measured electrical conductivity was comparable to that reported for polymer electrolyte composites prepared using passive fillers (non luminescent). This approach is therefore promising for production of high intensity luminescent polymer electrolyte composites for use in development of hybrid battery/display