Response analyzers for sensors Patent

Response analyzing apparatus for liquid vapor interface sensor of sloshing rocket propellan

Investigation of the Coupled Nuclear, Thermal-Hydraulic, and Thermomechanical Response of a Natural Circulation Research Reactor Under Severe Reactivity-Initiated Accident Transients

Research reactors play an important role in higher education, scientific research, and medical radioisotope production around the world. It is thus important to ensure the safety of facility workers and the public. This work presents a new reactor transient analysis code, referred to as Razorback, which computes the coupled reactor kinetics, fuel element heat transfer, fuel element thermal expansion and thermal stress, and thermal-hydraulic response of a natural circulation research reactor. The code was developed for the evaluation of large rapid reactivity addition in research reactors, with an initial focus on the Annular Core Research Reactor (ACRR) at Sandia National Laboratories. Razorback has been validated using ACRR pulse operations, and the simulation results are shown to agree very well with measured reactor data. Razorback is also used to examine the response of a natural circulation research reactor (i.e., the ACRR) to large rapid reactivity additions. The reactor kinetic response, the thermal-hydraulic response of the fuel and coolant, and the thermomechanical response of the fuel element materials are each examined separately. Safety analysis and operational implications are discussed

Fundamental rocket injector/spray programs at the Phillips Laboratory

The performance and stability of liquid rocket engines is determined to a large degree by atomization, mixing, and combustion processes. Control over these processes is exerted through the design of the injector. Injectors in liquid rocket engines are called upon to perform many functions. They must first of all mix the propellants to provide suitable performance in the shortest possible length. For main injectors, this is driven by the tradeoff between the combustion chamber performance, stability, efficiency, and its weight and cost. In gas generators and preburners, however, it is also driven by the possibility of damage to downstream components, for example piping and turbine blades. This can occur if unburned fuel and oxidant later react to create hot spots. Weight and cost considerations require that the injector design be simple and lightweight. For reusable engines, the injectors must also be durable and easily maintained. Suitable atomization and mixing must be produced with as small a pressure drop as possible, so that the size and weight of pressure vessels and turbomachinery can be minimized. However, the pressure drop must not be so small as to promote feed system coupled instabilities. Another important function of the injectors is to ensure that the injector face plate and the chamber and nozzle walls are not damaged. Typically this requires reducing the heat transfer to an acceptable level and also keeping unburned oxygen from chemically attacking the walls, particularly in reusable engines. Therefore the mixing distribution is often tailored to be fuel-rich near the walls. Wall heat transfer can become catastrophically damaging in the presence of acoustic instabilities, so the injector must prevent these from occurring at all costs. In addition to acoustic stability (but coupled with it), injectors must also be kinetically stable. That is, the flame itself must maintain ignition in the combustion chamber. This is not typically a problem with main injectors, but can be a consideration in preburners, where the desire to keep turbine inlet temperatures as cool as possible can make it advantageous for the preburners to operate as far from stoichiometry as can be tolerated. For some missions such as single stage to orbit, all of the above requirements must be maintained over a throttleable range, for example 5:1 to 10:1. Finally, the injectors must be ignitable during startup where pressures and temperatures are far from design conditions, and ignition transients must be minimized in order to avoid damage to engine components. In order to satisfy these various constraints, the injector designer must be able to perform design tradeoff studies, and it is important that this be done with minimal time and costs. In fact, it can easily be argued that reducing engine development time and costs is essential to maintaining U.S. competitiveness in space. The Propulsion Directorate of the Phillips Laboratory has invested in a number of programs to advance liquid rocket engine technology, and several of these are directed at improving design tools for liquid rocket injectors. The purpose of the presentation will be to describe some of these latter programs

Some properties of nearly premixed laminar flame propagation along weakly stratified layers in combustible gas mixtures

Nearly premixed laminar flame propagation along weakly stratified layers in combustible gas mixtures is examined theoretically in the limit of weak flame stretch, high activation energy, and unity Lewis number. The stratification is represented by the variation in flame temperature along the reaction zone. Stratification is shown to affect the propagation velocity by a convective loss mechanism and by a diffusive mechanism that could be termed flame thickening. Whether a given amount of stratification should be expected to increase or decrease the propagation velocity compared with that of a nonstratified mixture depends on the angle the flame makes to the flow. The propagation velocity is most sensitive to the stratification for small flame angles.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28735/1/0000562.pd

Detection of Bound Polycyclic Aromatic Hydrocarbon Residuals in Soils Through Direct Immunoassay: A Feasibility Study

Environmental immunoassay is the use of animal-derived antibodies that will specifically bind with targeted analytes, called antigens, to quantitatively measure levels of contamination of the analyte in the environment. Most commercially available forms of immunoassays require the analyte to be in solution. Therefore, for soil contaminants, the analyte must be extracted from the soil, usually by a strong solvent, prior to analysis. The potential inefficiency of the extraction process has led to the investigation of a method for direct detection in the solid phase. This project deals strictly with testing potential assay procedures using monoclonal antibodies specific to naphthalene and polyclonal antibodies specific to pyrene. These antibodies were developed by Strategic Diagnostics, Inc. (SDI) under ajoint agreement with Amoco Production Co. (APC). The testing of the antibodies for their ability to bind to the targeted analyte in solution and their cross reactivity, or ability to bind with other similar polycyclic aromatic hydrocarbons (PAR's), were tested exclusively by SDI, and only the results of these tests are discussed in this thesis. Dextran, a chain of sugar molecules, was used as a surrogate antibody in establishing procedures. This was done because the newly developed antibodies used in this study were available in very small quantities. There would be few chances for adjusting procedures and re-testing, and careful preparation for testing was crucial

Reduce Avoidable Hospitalisations: A Policy to Increase Value from Health Care Expenditures

An interdisciplinary examination of rates of avoidable hospitalizations in France and England to evaluate access to primary care and identify the extent to which these countries may be able to reduce hospital costs by investing in disease management and primary care

Shadowgraphy of transcritical cryogenic fluids

The future of liquid-rocket propulsion depends heavily on continued development of high pressure liquid oxygen/hydrogen systems that operate near or above the propellant critical states; however, current understanding of transcritical/supercritical injection and combustion is yet lacking. The Phillips Laboratory and the United Technologies Research Center are involved in a collaborative effort to develop diagnostics for and make detailed measurements of transcritical droplet vaporization and combustion. The present shadowgraph study of transcritical cryogenic fluids is aimed at providing insight into the behavior of liquid oxygen or cryogenic stimulants as they are injected into a supercritical environment of the same or other fluids. A detailed history of transcritical injection of liquid nitrogen into gaseous nitrogen at reduced pressures of 0.63 (subcritical) to 1.05 (supercritical) is provided. Also, critical point enhancement due to gas phase solubility and mixture effects is investigated by adding helium to the nitrogen system, which causes a distinct liquid phase to re-appear at supercritical nitrogen pressures. Liquid oxygen injection into supercritical argon or nitrogen, however, does not indicate an increase in the effective critical pressure of the system

Stabilization zone structure in jet diffusion flames from liftoff toblowout

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/77310/1/AIAA-1989-153-230.pd

Targeting Mitochondrial Dysfunction in CNS Injury Using Methylene Blue; Still a Magic Bullet?

Complex, multi-factorial secondary injury cascades are initiated following traumatic brain injury, which makes this a difficult disease to treat. The secondary injury cascades following the primary mechanical tissue damage, are likely where effective therapeutic interventions may be targeted. One promising therapeutic target following brain injury are mitochondria. Mitochondria are complex organelles found within the cell, which act as powerhouses within all cells by supplying ATP. These organelles are also necessary for calcium cycling, redox signaling and play a major role in the initiation of cell death pathways. When mitochondria become dysfunctional, there is a tendency for the cell to loose cellular homeostasis and can lead to eventual cell death. Targeting of mitochondrial dysfunction in various diseases has proven a successful approach, lending support to mitochondria as a pivotal player in TBI cell death and loss of behavioral function. Within this mixed mini review/research article there will be a general discussion of mitochondrial bioenergetics, followed by a brief discussion of traumatic brain injury and how mitochondria play an integral role in the neuropathological sequelae following an injury. We will also give an overview of one relatively new TBI therapeutic approach, Methylene Blue, currently being studied to ameliorate mitochondrial dysfunction following brain injury. We will also present novel experimental findings, that for the first time, characterize the ex vivo effect of Methylene Blue on mitochondrial function in synaptic and non-synaptic populations of mitochondria