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The use of biodiesel in conventional diesel engines results in increased NOx emissions; this presents a barrier to the widespread use of biodiesel. The origins of this phenomenon were investigated using the CFD KIVA3V code, which was modified to account for the physical properties of biodiesel and to incorporate semi-detailed mechanisms for its combustion and the formation of emissions. Parametric φ-T maps and 3D engine simulations were used to assess the impact of using oxygen-containing fuels on the rate of NO formation. It was found that using oxygen-containing fuels allows more O₂ molecules to present in the engine cylinder during the combustion of biodiesel, and this may be the cause of the observed increase in NO emissions.

In this study, an optimization-based approach for simulating the walking motion of a digital human model is presented. A spatial skeletal model having 55 degrees of freedom is used to demonstrate the approach. Design variables are the joint angle profiles. Walking motion is generated by minimizing the mechanical energy subjected to basic physical and kinematical constraints. A formulation for symmetric and periodic normal walking is developed and results are presented. Backpack and ground reaction forces are taken into account in the current formulation, and the effects of the backpack on normal walking are discussed.

This paper presents new capabilities of the virtual-human Santos™ introduced last year. Santos™ is an avatar that has extensive modeling and simulation features. It is a digital human model with over 100 degrees-of-freedom (DOF), where the hand model has 25 DOF, direct optimization-based method, and real-human like appearance. The newly developed analysis includes (1) a 25-DOF hand model that is the first step to study hand grasping; (2) posture prediction advances such as multiple end-effectors (two arms, two arms + head + legs), real-time inverse kinematics for posture prediction for any points, vision functionality; (3) dynamic motion prediction with external loads; and (4) musculosteletal modeling that includes determining muscle forces, and muscle stress.

A three phase catalytic mathematical model was developed for analysis and optimization of the volatile reactor assembly (VRA) used on International Space Station (ISS) Water Processor. The Langmuir-Hinshelwood Hougen-Watson (L-H) expression was used to describe the surface reaction rate. Small column experiments were used to determine the L-H rate parameters. The test components used in the experiments were acetic acid, acetone, ethanol, 1-propanol, 2-propanol and propionic acid. These compounds are the most prevalent ones found in the influent to the VRA reactor. The VRA model was able to predict performance of small column data and experimental data from the VRA flight experiment.

The constellation of satellites to be launched in the next few years to provide rapid global access to information needs low-cost and lightweight solar arrays. Multijunction thin-film amorphous silicon (a-Si) alloy solar cells deposited on lightweight and flexible substrates are ideal to meet this challenge. a-Si alloy is radiation hard, and has superior high temperature performance. We present results on fabrication of a-Si alloy solar cells on 0.5-mil-thick stainless steel using a low-cost production technology to achieve high efficiency under AM0 condition and their space qualification.

An investigation on the sequential turbocharging (ST) of a Kelvin TFSC6 medium speed diesel engine developing 320 kW at 1200 r/min is reported in this paper. The sequential turbocharging (ST) system, utilising turbochargers of unequal size, resulted in significant improvement when compared with previously designed systems. The engine test results show that the new ST system improves the engine performance at both high and low speeds except, at or near to, the ‘transfer’ speed. The engine low speed performance is improved with fuel saving of up to 7 g/kwh for the 1st sequence. However, the improvement of the high engine speed performance at the 2nd sequence was limited by some boost air leakage from a flexible connecting pipe from the peak unit compressor outlet to the intercooler inlet. An optimised sequence transfer control mode is also proposed in this research.

A computer based data acquisition and control system has been developed for IC engine research at Kelvin Engine Technology Unit (KETU). A computer program was designed and compiled using a graphical programming language known as LabVIEW for engine experimental studies and monitoring. A self-adaptive auto-load setting, specifically designed for an early type of dynamometer, is presented for engine operational control by computer. Both engine overall performance and dynamic pressure measurement results can be processed, analysed and displayed graphically during the engine test period. These methods have resulted in a compact and effective engine experimental study system.

Direct-injection spark-ignition (DISI) engines have been investigated for many years but only recently have shown promise as a next generation gasoline engine technology. Much of this new enthusiasm is due to advances in the fuel injection system, which is now capable of producing a well-controlled spray with small droplets. A physical understanding of new combustion systems utilizing this technology is just beginning to occur. This analytical and experimental investigation with a research single-cylinder combustion system shows the benefits of in-cylinder gasoline injection versus injection of fuel into the intake port. Charge cooling with direct injection is shown to improve volumetric efficiency and reduce the mixture temperature at the time of ignition allowing operation with a higher compression ratio which improves the thermodynamic cycle efficiency.