Measurement of the thermal conductivity of thin solid films with a thermal comparator

A direct-reading thermal comparator was used to measure the thermal conductivities of several thin solid films. This new application of the thermal comparator was based on heat flow modelling using the thermal constriction resistance, generalized here for the case of a film on the surface of an infinite half-space. Four dielectric optical coating materials were tested, and found to have thermal conductivities significantly lower than those for the same material in bulk form. The finite element method was used to estimate the minimum sample dimensions required for accurate results, and the variation of the thermal constriction resistance with the assumed mode of heat flow between the comparator probe tip and the test specimen

KIVA-3V: A block-structured KIVA program for engines with vertical or canted valves

This report describes an extended version of KIVA-3, known as KIVA-3V, that can model any number of vertical or canted valves in the cylinder head of an internal combustion (IC) engine. The valves are treated as solid objects that move through the mesh using the familiar snapper technique used for piston motion in KIVA-3. Because the valve motion is modeled exactly, and the valve shapes are as exact as the grid resolution will allow, the accuracy of the valve model is commensurate with that of the rest of the program. Other new features in KIVA-3V include a particle-based liquid wall film model, a new sorting subroutine that is linear in the number of nodes and preserves the original storage sequence, a mixing-controlled turbulent combustion model, and an optional RNG {kappa}-{epsilon} turbulence model. All features and capabilities of the original KIVA-3 have been retained. The grid generator, K3PREP, has been expanded to support the generation of grids with valves, along with the shaping of valve ports and runners. Graphics output options have also been expanded. The report discusses the new features, and includes four examples of grids with vertical and canted valves that are representative of IC engines in use today

Three dimensional numerical simulations of the UPS-292-SC engine

We present and analyze three-dimensional calculations of the spray, mixing and combustion in the UPS-292 stratified charge engine for three different operating conditions, corresponding to overall air-fuel ratios between 22.4 and 61.0. The numerical calculations are performed with KIVA, a multidimensional arbitrary-mesh, finite-difference hydrodynamics program for internal combustion engine applications. The calculations use a mesh of 10,000 computational cells, which conform to the shape of the piston bowl and cylinder and move to follow piston motion. Each operating condition is calculated from intake valve closure at 118/sup 0/ BTDC to 90/sup 0/ ATDC and requires approximately three hours of CRAY-XMP computer time

Surface tension implementation for Gensmac 2D

In the present work we describe a method which allows the incorporation of surface tension into the GENSMAC2D code. This is achieved on two scales. First on the scale of a cell, the surface tension effects are incorporated into the free surface boundary conditions through the computation of the capillary pressure. The required curvature is estimated by fitting a least square circle to the free surface using the tracking particles in the cell and in its close neighbors. On a sub-cell scale, short wavelength perturbations are filtered out using a local 4-point stencil which is mass conservative. An efficient implementation is obtained through a dual representation of the cell data, using both a matrix representation, for ease at identifying neighbouring cells, and also a tree data structure, which permits the representation of specific groups of cells with additional information pertaining to that group. The resulting code is shown to be robust, and to produce accurate results when compared with exact solutions of selected fluid dynamic problems involving surface tension

East Asia and the global/transatlantic/Western crisis

This paper introduces the special collection on East Asia and the Global Crisis. After justifying why a focus on East Asia is appropriate, it draws out the main themes that run through the individual contributions. These are the extent to which the region is decoupling from the global economy (or the West), the increasing legitimacy of statist alternatives to neoliberal development strategies, and the impact of crises on the definition of ―region‖ and the functioning of regional institutions and governance mechanisms

Hydrodynamic modeling of deconfinement phase transition in nuclear collisions

The (3+1)-dimensional ideal hydrodynamics is used to simulate collisions of gold nuclei with bombarding energies from 1 to 160 GeV per nucleon. The initial state is represented by two cold Lorentz-boosted nuclei. Two equations of state: with and without the deconfinement phase transition are used. We have investigated dynamical trajectories of compressed baryon-rich matter as functions of various thermodynamical variables. The parameters of collective flow and hadronic spectra are calculated. It is shown that presence of the deconfinement phase transition leads to increase of the elliptic flow and to flattening of proton rapidity distributions.Comment: 11 pages, 6 figure

The Middle-Income Trap: Issues for Members of the Association of Southeast Asian Nations

The problem faced by many of the economies making up the Association of Southeast Asian Nations (ASEAN) is whether they can avoid the middle-income trap and advance to the high-income level. What is needed for them to avoid the middle-income trap? This paper attempts to answer this question by building an analytical framework based on the factors that determine each development stage of an economy, and by comparing the current situation of four ASEAN middle-income countries with the experience of the Republic of Korea, a country that managed to overcome the middle-income trap and reach the high-income level in the late 1990s. The paper concludes that for ASEAN middle-income countries (Indonesia, Malaysia, the Philippines, and Thailand) to avoid the trap, they should strengthen research and development capability, emphasize the quality and appropriateness of human resources, and improve the institutional system for nourishing a dynamic private sector. These efforts can be expected to result in dynamic changes in the structure of comparative advantage toward higher skill and more innovation-intensive contents of products. For a low middle-income country such as Viet Nam, reforms and policies to increase the productivity of capital, land, and other resources are essential to avoid the early appearance of the trap

Progress toward an optimized hydrogen series hybrid engine

The design considerations and computational fluid dynamics (CFD) modeling of a high efficiency, low emissions, hydrogen-fueled engine for use as the prime mover of a series hybrid automobile is described. The series hybrid automobile uses the engine to generate electrical energy via a lightweight generator, the electrical energy is stored in a power peaking device (like a flywheel or ultracapacitor) and used as required to meet the tractive drive requirements (plus accessory loads) through an electrical motor. The engine/generator is stopped whenever the energy storage device is fully charged. Engine power output required was determined with a vehicle simulation code to be 15 to 20 kW steady state with peak output of 40 to 45 kW for hill climb. Combustion chamber and engine geometry were determined from a critical review of the hydrogen engine experiments in the literature combined with a simplified global engine model. Two different engine models are employed to guide engine design. The models are a simplified global engine performance model that relies strongly on correlations with literature data for heat transfer and friction losses, and a state-of-the-art CFD combustion model, KIVA-3, to elucidate fluid mechanics and combustion details through full three-dimensional modeling. Both intake and exhaust processes as well as hydrogen combustion chemistry and thermal NO{sub x} production are simulated. Ultimately, a comparison between the simulation and experimental results will lead to improved modeling and will give guidance to changes required in the next generation engine to achieve the goal of 45% brake thermal efficiency