32 research outputs found
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Systems and methods of continuously producing encapsulated liquid water
Disclosed are systems and methods for continuously producing dry water from silica and water and from silica, sodium bicarbonate, and water.Board of Regents, University of Texas Syste
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Systems and methods of continuously producing encapsulated liquid water
Disclosed are systems and methods for continuously producing dry water from silica and water and from silica, sodium bicarbonate, and water.Board of Regents, University of Texas Syste
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Portable fluid warming system
The present invention relates to a portable apparatus for warming biocompatible fluids for use in the treatment of injured patients and a method of heating a biocompatible fluid to treat a patient experiencing hypothermia. The present invention may be used to warm intravenous fluids for trauma resuscitation or to warm air from a ventilator circuit. The portable nature of the present invention makes it highly suitable for field applications, such as a forward surgical hospital near a combat zone.Board of Regents, University of Texas Syste
ICES 2005-1031 RAILPLUG DESIGN OPTIMIZATION TO IMPROVE LARGE-BORE NATURAL GAS ENGINE PERFORMANCE
ABSTRACT It is a very challenging problem to reliably ignite extremely lean mixtures, especially for the low speed, high load conditions of stationary large-bore natural gas engines. If these engines are to be used for the distributed power generation market, it will require operation with higher boost pressures and even leaner mixtures. Both place greater demands on the ignition system. The railplug is a very promising ignition system for lean burn natural gas engines with its high-energy deposition and high velocity plasma jet. High-speed photography was used to study the dis charge process. A heat transfer model is proposed to aid the railplug design. A parameter study was performed both in a constant volume bomb and in an operating natural gas engine to improve and optimize the railplug designs. The engine test results show that the newly designed railplugs can ensure the ignition of very lean natural gas mixtures and extend the lean stability limit significantly. The new railplug designs also improve durability. INTRODUCTION Over the past few years, industry and government have jointed together to develop high efficiency, low emissions, large-bore natural gas fueled stationary engines for either natural gas transportation or power generation. They have targeted fuel efficiency at over 50%, NO x emissions as low as 0.01 gm/BHP-hr, and decreasing maintenance costs by 10% [1]. This will require operation with higher boost pressures and even leaner mixtures. Both place greater demands on the ignition system
Hakan Ertürk The Application of an Inverse Formulation in the Design of Boundary Conditions for Transient Radiating Enclosures
This study considers the design of thermal systems that are built to radiatively heat objects from a specified initial condition to a specified steady state following a prescribed temperature history
Treatment of Design Fire Uncertainty using Quadrature Method of Moments
The use of a single design fire in a performance based fire design code typically fails to
account for the inherent uncertainty in knowledge of the future use of the space.
Uncertainties in knowledge of intended use and the implications in terms of fuel loading
and potential heat release rate can be bounded using probabilistic methods. Use of a
cumulative distribution function (CDF) and the related probability density function (PDF)
specify the best available estimate of the probability (likelihood) of a fire of given size to
take place in a compartment. Monte Carlo simulation is a widely used computational
method for treating uncertainty that might be described by a PDF . In this technique, one
samples the uncertain variables from their underlying PDFs and runs a fire model for
each sample. For complex fire models, this approach may be computationally intractable.
In this work we present a computationally efficient technique called the Quadrature
Method of Moments (QMOM) for propagating uncertainty bound in distributions. In
QMOM one solves for only the moments of a relevant uncertain parameter. The
cumulative distribution function (CDF) of the uncertain parameter provides all the
statistical information required for risk assessments. We consider a simplified
propagation of uncertainty problem. Results using both the ASET and CFAST fire
models indicate that computation of the moments of the PDF using QMOM and the
reconstruction of the CDF by matching the moments with those of a 4-parameter
Generalized Lambda Distribution (GLD) give accurate results at a significantly smaller
computational cost
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EMSP Final Report: Electrically Driven Technologies for Radioactive Aerosol Abatement
The purpose of this research project was to develop an improved understanding of how electrically driven processes, including electrocoalescence, acoustic agglomeration, and electric filtration, may be employed to efficiently treat problems caused by the formation of aerosols during DOE waste treatment operations. The production of aerosols during treatment and retrieval operations in radioactive waste tanks and during thermal treatment operations such as calcination presents a significant problem of cost, worker exposure, potential for release, and increased waste volume. There was anecdotal evidence in the literature that acoustic agglomeration and electrical coalescence could be used together to change the size distribution of aerosol particles in such a way as to promote easier filtration and less frequent maintenance of filtration systems. As such, those electrically driven technologies could potentially be used as remote technologies for improved treatment; however, existing theoretical models are not suitable for prediction and design. To investigate the physics of such systems, and also to prototype a system for such processes, a collaborative project was undertaken between Oak Ridge National Laboratory (ORNL) and the University of Texas at Austin (UT). ORNL was responsible for the larger-scale prototyping portion of the project, while UT was primarily responsible for the detailed physics in smaller scale unit reactors. It was found that both electrical coalescence and acoustic agglomeration do in fact increase the rate of aggregation of aerosols. Electrical coalescence requires significantly less input power than acoustic agglomeration, but it is much less effective in its ability to aggregate/coalesce aerosols. The larger-scale prototype showed qualitatively similar results as the unit reactor tests, but presented more difficulty in interpretation of the results because of the complex multi-physics coupling that necessarily occur in all larger-scale system tests. An additional finding from this work is that low-amplitude oscillation may provide an alternative, non-invasive, non-contact means of controlling settling and/or suspension of solids. Further investigation would be necessary to evaluate its utility for radioactive waste treatment applications. This project did not uncover a new technology for radioactive waste treatment. While it may be possible that an efficient electrically driven technology for aerosol treatment could be developed, it appears that other technologies, such as steel and ceramic HEPA filters, can suitably solve this problem. If further studies are to be undertaken, additional fundamental experimentation and modeling is necessary to fully capture the physics; in addition, larger-scale tests are needed to demonstrate the treatment of flowing gas streams through the coupling of acoustic agglomeration with electrocoalescence
Extension of the PECOS Quasi-steady Ablation Toolkit for Uncertainty Propagation
Low-order models are quite useful for sensitivity analysis and design. This work details work done on adding complementary pieces to the PECOS low-order, quasi-steady-state ablation model to facilitate uncertainty propagation. The PECOS quasi-steady state ablation model is a one-dimensional, quasi-steady-state, algebraic ablation model that uses finite-rate surface chemistry and equilibrium pyrolysis-gas-production submodels to predict surface recession rate. The material response model is coupled to a film-transfer boundary layer model to enable the computation of heat and mass transfer from an ablating surface. For comparison to arc jet data, a simple shock heated gas model is coupled. A coupled model consisting of submodels for the shock heated gases, film heat and mass transfer, and material response is exercised against recession rate data for surface and in-depth ablators. Comparisons are made between the quasi-state-state ablation model and the unsteady ablation code, Chaleur, as well as to other computations for a graphite ablator in arcjet facilities. The simple models are found to compare reasonably well to both the experimental results and the other calculations. Uncertainty propagation using a moment based methods is presented. The method is applied to a number of simplified sample problems, for both univariate and multivariate scenarios. The results of this study are discussed, and conclusions about the utility of the method as well as the properties of the ablation code are drawn
Thermoplastic Polyurethane Elastomer Nanocomposites: Morphology, Thermophysical, and Flammability Properties
Novel materials based on nanotechnology creating nontraditional ablators are rapidly changing the technology base for thermal protection systems. Formulations with the addition of nanoclays and carbon nanofibers in a neat thermoplastic polyurethane elastomer (TPU) were melt-compounded using twin-screw extrusion. The TPU nanocomposites (TPUNs) are proposed to replace Kevlar-filled ethylene-propylene-diene-monomer rubber, the current state-of-the-art solid rocket motor internal insulation. Scanning electron microscopy analysis was conducted to study the char characteristics of the TPUNs at elevated temperatures. Specimens were examined to analyze the morphological microstructure during the pyrolysis reaction and in fully charred states. Thermophysical properties of density, specific heat capacity, thermal diffusivity, and thermal conductivity of the different TPUN compositions were determined. To identify dual usage of these novel materials, cone calorimetry was employed to study the flammability properties of these TPUNs