The influence of yttrium oxide coating processed by the sol-gel method on the oxidation behaviour of a commercial FeCrAl alloy Kanthal A1 has been investigated during isothermal exposures in air at K. The scale growth kinetics of the uncoated alloy obey a parabolic rate law during the whole oxidation test, whereas the kinetic curves of the Y-coated specimen exhibit an initial transient stage for the first few hours, followed by a parabolic regime.
The yttrium sol-gel coating deposited on the bare alloy does not provide the beneficial effect usually ascribed to reactive elements. No oxidation rate improvement of the coated alloy is observed, the parabolic rate constant values are strictly identical for both specimens. In situ X-ray diffraction reveals a marked influence of the reactive element on the composition of the oxide scale.
High temperature strain gages. A ceramic strain gage based on reactively sputtered indium-tin-oxide ITO thin films is used to monitor the structural integrity of components employed in aerospace propulsion systems operating at temperatures in excess of A scanning electron microscopy SEM of the thick ITO sensors reveals a partially sintered microstructure comprising a contiguous network of submicron ITO particles with well defined necks and isolated nanoporosity.
Densification of the ITO particles was retarded during high temperature exposure with nitrogen thus stabilizing the nanoporosity. Under these conditions, sintering and densification of the ITO particles containing these nitrogen rich grain boundaries was retarded and a contiguous network of nano-sized ITO particles was established.
Reactive high power impulse magnetron sputtering. The discharge current waveform is highly dependent on both the pulse repetition frequency and discharge voltage. The discharge current increases with decreasing frequency or voltage.
This we attribute to an increase in the secondary electron emission yield during the self-sputtering phase of the pulse, as nitride  or oxide  forms on the target. The HiPIMS process produces denser films at lower growth temperature and the surface is much smoother and have a significantly lower resistivity than dc magnetron sputtered films on SiO2 at all growth temperatures due to reduced grain boundary scattering .
Gudmundsson, N. Brenning, D. Lundin and U. Helmersson, J. A, 30 [0pt]  F. Magnus, O. Sveinsson, S. Olafsson and J. Gudmundsson, J. Magnus, T. Tryggvason, S. Magnus, A. Ingason, S. High temperature furnace. A high temperature furnace for use above C is provided that features fast initial heating and low power consumption at the operating temperature.
The cathode is initially heated by joule heating followed by electron emission heating at the operating temperature. The cathode is designed for routine large temperature excursions without being subjected to high thermal stresses. A further characteristic of the device is the elimination of any ceramic components from the high temperature zone of the furnace. High Temperature Aquifer Storage. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant.
It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Apart from the hydrogeological conditions, high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer.
After one year of planning, construction, and the successful drilling of a research well to m b. About 4 TJ of heat energy were necessary to achieve the desired water temperatures. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for the analysis of the concentration of the tracers and the cation concentrations at sampling intervals of down to 15 minutes.
Additional water samples were taken and analyzed for major ions and trace elements in the laboratory. The disassembled heat exchanger proved that precipitation was successfully prevented by adding CO2 to the water before heating. High temperature sensor. A high temperature sensor includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range 1, to 2, K.
When required, the sensor can be encased within a ceramic protective coating. Apart from high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. To achieve the desired water temperatures , about 4 TJ of heat energy were necessary. A laboratory container at the drilling site was equipped for analysing the concentration of the dyes and the major cations at sampling intervals of down to 15 minutes.
Additional water samples were taken and analysed in the laboratory. The disassembled heat exchanger prooved that precipitation was successfully prevented by adding CO2 to the water before heating. Nevertheless, hydrochemical data proved both, dissolution and precipitation processes in the aquifer. This was also suggested by the hydrochemical modelling with PhreeqC and is traced back to mixture dissolution and changing.
Materials for high -pressure turbine blades must be able to operate in the high-temperature gases above C emerging from the combustion chamber. However, the melting point of nickel C provides a natural ceiling for the temperature capability of nickel-based superalloys.
It was. High temperature refrigerator. A high temperature magnetic refrigerator which uses a Stirling-like cycle in which rotating magnetic working material is heated in zero field and adiabatically magnetized, cooled in high field, then adiabatically demagnetized. During this cycle said working material is in heat exchange with a pumped fluid which absorbs heat from a low temperature heat source and deposits heat in a high temperature reservoir.
High temperature measuring device. A temperature measuring device for very high design temperatures to 2, The device comprises a homogenous base structure preferably in the form of a sphere or cylinder. The base structure contains a large number of individual walled cells.
The base structure has a decreasing coefficient of elasticity within the temperature range being monitored. A predetermined quantity of inert gas is confined within each cell. The cells are dimensionally stable at the normal working temperature of the device. Increases in gaseous pressure within the cells will permanently deform the cell walls at temperatures within the high temperature range to be measured.
Such deformation can be correlated to temperature by calibrating similarly constructed devices under known time and temperature conditions. High-temperature sensor. A high temperature sensor is described which includes a pair of electrical conductors separated by a mass of electrical insulating material. High temperature alloy. Molybdenum is substituted for tungsten on an atomic basis in a cobalt-based alloy, S-1, thus enabling the alloy to be formed into various mill products, such as tubing and steels.
The alloy is weldable, has good high temperature strength and is not subject to embrittlement produced by high temperature aging. Consequently, the chromium—iron oxide catalyst surface is dominated by FeO x sites, but some minor reduced surface chromia sites are also retained.
The Fe 3—-xCr xO 4 solid solution stabilizes the iron oxide phase from reducing to metallic Fe0 and imparts an enhanced surface area to the catalyst. Safe Disposal of Highly Reactive Chemicals. Provides specific procedures for the disposal of a variety of highly reactive chemicals and reports the results of a study of their safe disposal.
Disposal of some problematic sulfur-containing compounds are included. Procedures are based on a combination of literature review and author development. High Temperature Semiconductor Process. A sputtering deposition system capable of depositing large areas of high temperature superconducting materials was developed by CVC Products, Inc.
The system was devleoped for NASA to produce high quality films of high temperature superconducting material for microwave communication system components. The system is also being used to deposit ferroelectric material for capacitors and the development of new electro-optical materials. High-temperature electronics. To meet the needs of the aerospace propulsion and space power communities, the high temperature electronics program at the Lewis Research Center is developing silicon carbide SiC as a high temperature semiconductor material.
This program supports a major element of the Center's mission - to perform basic and developmental research aimed at improving aerospace propulsion systems. Research is focused on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of SiC devices.
High temperature pressure gauge. A high temperature pressure gauge comprising a pressure gauge positioned in fluid communication with one end of a conduit which has a diaphragm mounted in its other end. The conduit is filled with a low melting metal alloy above the diaphragm for a portion of its length with a high temperature fluid being positioned in the remaining length of the conduit and in the pressure gauge.
High temperature probe. A high temperature probe for sampling, for example, smokestack fumes, and is able to withstand temperatures of The probe is constructed so as to prevent leakage via the seal by placing the seal inside the water jacket whereby the seal is not exposed to high temperature , which destroys the seal.
The sample inlet of the probe is also provided with cooling fins about the area of the seal to provide additional cooling to prevent the seal from being destroyed. Also, a heated jacket is provided for maintaining the temperature of the gas being tested as it passes through the probe.
The probe includes pressure sensing means for determining the flow velocity of an efficient being sampled. In addition, thermocouples are located in various places on the probe to monitor the temperature of the gas passing there through.
In situ X-ray diffraction contribution to the study of reactive element oxide coating effect on the high temperature oxidation behaviour of FeCrAl alloys. The influence of yttrium oxide coating processed by sol-gel method on the oxidation behaviour of a commercial FeCrAl alloy Kanthal A1 has been investigated during isothermal exposures in air at K.
The scale growth kinetic of the uncoated alloy obeys a parabolic rate law during the whole oxidation test whereas the kinetic curve of the Y-coated specimen exhibits an initial transient stage during the first hours, followed by a parabolic regime. The yttrium sol-gel coating deposited on the bare alloy does not conduct to the beneficial effect usually ascribed to the reactive elements. No oxidation rate improvement of the coated alloy is observed, the parabolic rate constants values are strictly identical for the both specimens.
High Temperature Piezoelectric Drill. The Venus environment represents several extremes including high temperature deg C , high pressure 9 MPa , and potentially corrosive condensed sulfuric acid droplets that adhere to surfaces during entry environments. This technology challenge requires new rock sampling tools for these extreme conditions. Piezoelectric materials can potentially operate over a wide temperature range. Single crystals, like LiNbO3, have a Curie temperature that is higher than deg C and the piezoelectric ceramics Bismuth Titanate higher than deg C.
A study of the feasibility of producing piezoelectric drills that can operate in the temperature range up to deg C was conducted. The study includes the high temperature properties investigations of engineering materials and piezoelectric ceramics with different formulas and doping. The detailed results of our study and a discussion of the future work on performance improvements are presented in this paper. High temperature solar receiver.
The development of a high temperature solar thermal receiver is described. A prototype receiver and associated test support auxiliary hardware was fabricated. Shakedown and initial performance tests of the prototype receiver were performed. The window retaining assembly was modified to improve its tolerance for thermal distortion of the flanges. It is shown that cost effective receiver designs can be implemented within the framework of present materials technology.
High Temperature Structural Foam. The Aerospace Industry is experiencing growing demand for high performance polymer foam. The X program needs structural foam insulation capable of retaining its strength over a wide range of environmental conditions. The High Speed Research Program has a need for low density core splice and potting materials. This paper reviews the state of the art in foam materials and describes experimental work to fabricate low density, high shear strength foam which can withstand temperatures from C to C.
Commercially available polymer foams exhibit a wide range of physical properties. Some with densities as low as 0. Rohacell foams can be resin transfer molded at temperatures up to C. They have moduli of elasticity of 0. The Rohacell foams cannot withstand liquid hydrogen temperatures , however Imi-Tech markets Solimide trademark foams which withstand temperatures from C to C, but they do not have the required structural integrity.
The research activity at NASA Langley Research Center focuses on using chemical blowing agents to produce polyimide thermoplastic foams capable of meeting the above performance requirements. The combination of blowing agents that decompose at the minimum melt viscosity temperature together with plasticizers to lower the viscosity has been used to produce foams by both extrusion and oven heating.
The foams produced exhibit good environmental stability while maintaining structural properties. High-Temperature Superconductivity. This invention contemplates a high temperature thermocouple for use in an inert or a reducing atmosphere. The thermocouple limbs are made of rhenium and graphite and these limbs are connected at their hot ends in compressed removable contact.
The rhenium and graphite are of high purity and are substantially stable and free from diffusion into each other even without shielding. Also, the graphite may be thick enough to support the thermocouple in a gas stream.
High temperature thermometric phosphors. A high temperature phosphor consists essentially of a material having the general formula LuPO. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined.
The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopent. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions.
The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopant. In recent years, there was a growing need for electronics capable of sustained high-temperature operation for aerospace propulsion system instrumentation, control and condition monitoring, and integrated sensors.
The desired operating temperature in some applications exceeds C, which is well beyond the capability of currently available semiconductor devices. Silicon carbide displays a number of properties which make it very attractive as a semiconductor material, one of which is the ability to retain its electronic integrity at temperatures well above C.
An IR award was presented to NASA Lewis in for developing a chemical vapor deposition process to grow single crystals of this material on standard silicon wafers. Silicon carbide devices were demonstrated above C, but much work remains in the areas of crystal growth, characterization, and device fabrication before the full potential of silicon carbide can be realized. The presentation will conclude with current and future high-temperature electronics program plans. Although the development of silicon carbide falls into the category of high -risk research, the future looks promising, and the potential payoffs are tremendous.
Borylnitrenes: electrophilic reactive intermediates with high reactivity towards C-H bonds. The present article summarizes the matrix isolation investigations that were aimed at identifying, characterizing and investigating the chemical behaviour of 3a by spectroscopic means, and of the experiments in solution and in the gas phase that were performed with 3b. Comparison with the reactivity reported for difluorovinylidene 1a in solid argon indicates that 3a shows by and large similar reactivity , but only after photochemical excitation.
The derivative 3b inserts into the C-H bonds of hydrocarbon solvents in high yields and thus allows the formation of primary amines, secondary amines, or amides from "unreactive" hydrocarbons. It can also be used for generation of methylamine or methylamide from methane in the gas phase at room temperature. Remaining challenges in the chemistry of borylnitrenes are briefly summarized.
High temperature materials characterization. A lab facility for measuring elastic moduli up to C was constructed and delivered. It was shown that the ultrasonic method can be used to determine elastic constants of materials from room temperature to their melting points.
The ease in coupling high frequency acoustic energy is still a difficult task. Even now, new coupling materials and higher power ultrasonic pulsers are being suggested. The surface was only scratched in terms of showing the full capabilities of either technique used, especially since there is such a large learning curve in developing proper methodologies to take measurements into the high temperature region.
The laser acoustic system does not seem to have sufficient precision at this time to replace the normal buffer rod methodology. High Temperature Thermosets. A thermoset or network polymer is an organic material where the molecules are tied together through chemical bonds crosslinks and therefore they cannot move past one another. As a result, these materials exhibit a certain degree of dimensional stability.
The chemical composition and the degree of crosslink density of the thermoset have a pronounced effect upon the properties. High temperature thermosets offer a favorable combination of properties that makes them attractive for many applications. Their most important features are the excellent processability particularly of the low molecular weight precusor forms, the chemical and solvent resistance and the dimensional stability.
The market for high temperature thermosets will increase as new uses for them are uncovered and new thermosets with better combinations of properties are developed. High temperature adhesives. The aerospace and electronics industries have an ever increasing need for higher performance materials. In recent years, linear aromatic polyimides have been proven to be a superior class of materials for various applications in these industries.
The use of this class of polymers as adhesives is continuing to increase. An apparatus of the stellarator type for heating a plasma to high temperatures is designed. Circularizers at the end of then helical windings produce a circular magnetic surface and provide improved confining and heating of the plasma. Reverse curvature sections formed in the end loops of the reaction tube provide increased plasma pressure for a given magnetic field pressure and thereby minimize the current flow in the helical windings.
Venus is one of the planets in the solar systems that are considered for potential future exploration missions. It has extreme environment where the average temperature is deg C and its ambient pressure is about 90 atm. Since the existing actuation technology cannot maintain functionality under the harsh conditions of Venus, it is a challenge to perform sampling and other tasks that require the use of moving parts.
Specifically, the currently available electromagnetic actuators are limited in their ability to produce sufficiently high stroke, torque, or force. In contrast, advances in developing electro-mechanical materials such as piezoelectric and electrostrictive have enabled potential actuation capabilities that can be used to support such missions. The detailed results of our study are presented in this paper. High temperature acoustic levitator.
A system is described for acoustically levitating an object within a portion of a chamber that is heated to a high temperature , while a driver at the opposite end of the chamber is maintained at a relatively low temperature. The cold end of the chamber is constructed so it can be telescoped to vary the length L sub 1 of the cold end portion and therefore of the entire chamber, so that the chamber remains resonant to a normal mode frequency, and so that the pressure at the hot end of the chamber is maximized.
The precise length of the chamber at any given time, is maintained at an optimum resonant length by a feedback loop. The feedback loop includes an acoustic pressure sensor at the hot end of the chamber, which delivers its output to a control circuit which controls a motor that varies the length L of the chamber to a level where the sensed acoustic pressure is a maximum.
High temperature detonator. A detonator assembly is provided which is usable at high temperatures about A detonator body is provided with an internal volume defining an anvil surface. A first acceptor explosive is disposed on the anvil surface. A donor assembly having an ignition element, an explosive material, and a flying plate, are placed in the body effective to accelerate the flying plate to impact the first acceptor explosive on the anvil for detonating the first acceptor explosive.
A second acceptor explosive is eccentrically located in detonation relationship with the first acceptor explosive to thereafter effect detonation of a main charge. Ceramics at High Temperatures. With increasing sintering temperature , the Seebeck coefficient decreases while the electrical conductivity increases. The temperature dependence of the electrical conductivity follows the rule of adiabatic hopping conduction of small polarons.
The calculated density of states of CCTO indicates that the conduction band is mainly contributed by the antibonding states of Cu 3 d electrons, therefore small-polaron hopping between CuO4 square planar clusters was proposed. Possible ways to further improve the thermoelectric properties of CCTO are also discussed. Measurements of Venus surface chemistry suggest a basaltic composition with a predominantly CO2 atmosphere. In order to understand the reactivity of certain possible mineral species on the surface, previous simulation chambers conduct experiments at 1 atmosphere with a simplified CO2 atmosphere.
Following this procedure, pyrite FeS2 samples are used to estimate the reactivity of sulfide minerals under a Venusian atmosphere and climate. Sulfurous gas species have been identified and quantified in the Venusian atmosphere, and sulfurous gas and mineral species are known to be created through volcanism, which is suggested to still occur on the surface of Venus. This experimentation is necessary to constrain reactions that could occur between the surface and atmosphere of Venus to understand terrestrial geology in a thick and hot greenhouse atmosphere.
Quantifying this reaction can lead to approximations necessary for further experimentation in more complex environments such as those in the GEER chamber at Glenn Research Center that can simulate pressure along with temperature and a more inclusive and representative Venusian atmosphere.
High Temperature Protonic Conductors. High Temperature Protonic Conductors HTPC with the perovskite structure are envisioned for electrochemical membrane applications such as H2 separation, H2 sensors and fuel cells.
Successive membrane commercialization is dependent upon addressing issues with H2 permeation rate and environmental stability with CO2 and H2O. HTPC membranes are conventionally fabricated by solid-state sintering. Grain boundaries and the presence of intergranular second phases reduce the proton mobility by orders of magnitude than the bulk crystalline grain. To enhanced protonic mobility, alternative processing routes were evaluated.
A laser melt modulation LMM process was utilized to fabricate bulk samples, while pulsed laser deposition PLD was utilized to fabricate thin film membranes. Thin film BaCe 0. Electron microscopy with chemical mapping was done to characterize the resultant microstructures. High temperature protonic conduction was measured by impedance spectroscopy in wet air or H2 environments. The results demonstrate the advantage of thin film membranes to thick membranes but also reveal the negative impact of defects or nanoscale domains on protonic conductivity.
High temperature ablative foam. An ablative foam composition is formed of approximately to parts by weight polymeric isocyanate having an isocyanate functionality of 2. High temperature polymer concrete. This invention is concerned with a polymer concrete composition, which is a two-component composition useful with many bases including metal.
Component A, the aggregate composition, is broadly composed of silica, silica flour, portland cement, and acrylamide, whereas Component B, which is primarily vinyl and acrylyl reactive monomers, is a liquid system. In this study, SiCNTs were investigated for use in strengthening high temperature silicate and oxide materials for high performance ceramic nanocomposites and environmental barrier coating bond coats. The SiCNTs were synthesized by a direct reactive conversion process of multiwall carbon nanotubes and silicon at high temperature.
The specific oxidation mechanisms were also investigated. High-temperature resins. The basic chemistry, cure processes, properties, and applications of high temperature resins known as polyimides are surveyed. Condensation aromatic polymides are prepared by reacting aromatic diamines with aromatic dianhydrides, aromatic tetracarboxylic acids, or with dialkyl esters of aromatic tetracarboxylic acids, depending on the intended end use. The first is for coatings or films while the latter two are more suitable for polyimide matrix resins.
Prepreg solutions are made by dissolving reactants in an aprotic solvent, and advances in the addition of a diamine on the double bond and radical polymerization of the double bond are noted to have yielded a final cure product with void-free characteristics. Attention is given to properties of the Skybond, Pyralin, and NRB polyimide prepreg materials and characteristics of aging in the NP polyimides.
High temperature interfacial superconductivity. High-temperature superconductivity confined to nanometer-scale interfaces has been a long standing goal because of potential applications in electronic devices. The spontaneous formation of a superconducting interface in bilayers consisting of an insulator La.
Depending upon the layering sequence of the bilayers, T. This highly robust phenomenon is confined to within nm around the interface. After exposing the bilayer to ozone, T. The results demonstrate that engineering artificial heterostructures provides a novel, unconventional way to fabricate stable, quasi two-dimensional high T. As a part of the solution searching for possibility to control the plutonium, a current effort is focused on mechanisms to maximize consumption of plutonium.
Plutonium core solution is a unique case in the high temperature reactor which is intended to reduce the accumulation of plutonium. However, the safety performance of the plutonium core which tends to produce a positive temperature coefficient of reactivity should be examined. The pebble bed inherent safety features which are characterized by a negative temperature coefficient of reactivity must be maintained under any circumstances.
The purpose of this study is to investigate the characteristic of temperature coefficient of reactivity for plutonium core of pebble bed reactor. A series of calculations with plutonium loading varied from 0. The calculation results show that the k eff curve of 0. The fuel with high Pu content per pebble may reach long burnup cycle.
From the temperature coefficient point of view, it is concluded that the reactor containing 0. The use of fuel with Pu content of 1. Self- reactive materials which require temperature High Temperature Superconducting Materials Database.
Collisional quenching dynamics and reactivity of highly vibrationally excited molecules. Lower limits to the overall collision rate are directly determined from experimental measurements and compared to Lennard-Jones models which underestimate the collision rate for highly vibrationally excited azabenzenes with HOD.
The fourth study explores reactive collisions of highly vibrationally excited pyridine molecules. A single quantum of C-D stretching vibration is observed to be used for the vibrational driven reaction. Reactions of 2-picoline-d3 with chlorine radical do not show a similar enhancement.
For this case, the fast rotation of --CD3 group in highly vibrationally excited 2-picoline-d3 inhibits the D-atom abstraction. High temperature lubricating process. The process comprises contacting and maintaining the following steps: a gas phase is provided which includes at least one component reactable in a temperature dependent reaction to form a solid lubricant; the gas phase is contacted with the load bearing surface; the load bearing surface is maintained at a temperature which causes reaction of the gas phase component and the formation of the solid lubricant; and the solid lubricant is formed directly on the load bearing surface.
The method is particularly suitable for use with ceramic engines. It has been difficult to provide adaquate lubrication for load bearing, engine components when such engines are operating in excess of about The present invention is a process for providing a solid lubricant on a load bearing, solid surface 14 , such as in an engine 10 being operated at temperatures in excess of about The process comprises contacting and maintaining steps.
A gas phase 42 is provided which includes at least one component reactable in a temperature dependent reaction to form a solid lubricant. The gas phase is contacted with the load bearing surface. The load bearing surface is maintained at a temperature which causes reaction of the gas phase component and the formation of the solid lubricant.
The solid lubricant is formed directly on the load bearing surface. High-Temperature Piezoelectric Sensing. Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques.
Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented. The evolution of the temperature field during cavity collapse in liquid nitromethane. Part II: reactive case. This work is concerned with the effect of cavity collapse in non-ideal explosives as a means of controlling their sensitivity.
The main objective is to understand the origin of localised temperature peaks hot spots which play a leading order role at the early stages of ignition. To this end, we perform two- and three-dimensional numerical simulations of shock-induced single gas-cavity collapse in liquid nitromethane. Ignition is the result of a complex interplay between fluid dynamics and exothermic chemical reaction.
In the first part of this work, we focused on the hydrodynamic effects in the collapse process by switching off the reaction terms in the mathematical formulation. In this part, we reinstate the reactive terms and study the collapse of the cavity in the presence of chemical reactions. By using a multi-phase formulation which overcomes current challenges of cavity collapse modelling in reactive media, we account for the large density difference across the material interface without generating spurious temperature peaks, thus allowing the use of a temperature -based reaction rate law.
The mathematical and physical models are validated against experimental and analytic data. In Part I, we demonstrated that, compared to experiments, the generated hot spots have a more complex topological structure and that additional hot spots arise in regions away from the cavity centreline. Here, we extend this by identifying which of the previously determined high-temperature regions in fact lead to ignition and comment on the reactive strength and reaction growth rate in the distinct hot spots.
We demonstrate and quantify the sensitisation of nitromethane by the collapse of the isolated cavity by comparing the ignition times of nitromethane due to cavity collapse and the ignition time of the neat material. The ignition in both the centreline hot spots and the hot spots generated by Mach stems occurs in less than half the ignition time of the neat material. We compare. Fast screening of analytes for chemical reactions by reactive low- temperature plasma ionization mass spectrometry.
Approaches for analyte screening have been used to aid in the fine-tuning of chemical reactions. Herein, we present a simple and straightforward analyte screening method for chemical reactions via reactive low- temperature plasma ionization mass spectrometry reactive LTP-MS. Solution-phase reagents deposited on sample substrates were desorbed into the vapor phase by action of the LTP and by thermal desorption. Products from the imine formation reaction with reagents substituted with different functional groups 26 out of 28 trials were successfully screened in a time of 30 s each.
Besides, two short-lived reactive intermediates of Eschweiler-Clarke methylation were also detected. The present reactive LTP-MS method enables fast screening for several analytes from several chemical reactions, which possesses good reagent compatibility and the potential to perform high -throughput analyte screening.
In addition, with the detection of various reactive intermediates intermediates I and II of Eschweiler-Clarke methylation , the present method would also contribute to revealing and elucidating reaction mechanisms. High Temperature Electronics Technology. Since tape tests removed almost none of the This refers to the undoped no nitrogen stuffing variety not the Ti-W diffusion High-temperature -measuring device.
The cells are dimensonally stable at the normal working temperature of the device. Temperature effect on phase state and reactivity controls atmospheric multiphase chemistry and transport of PAHs. Polycyclic aromatic hydrocarbons like benzo a pyrene BaP in atmospheric particulate matter pose a threat to human health because of their high carcinogenicity.
In the atmosphere, BaP is mainly degraded through a multiphase reaction with ozone, but the fate and atmospheric transport of BaP are poorly characterized. Moreover, the effects of diffusion on the particle bulk are not well constrained, leading to large discrepancies between model results and observations.
We show how regional and global distributions and transport of BaP can be explained by a new kinetic scheme that provides a realistic description of the temperature and humidity dependence of phase state, diffusivity, and reactivity of BaP-containing particles.
Low temperature and humidity can substantially increase the lifetime of BaP and enhance its atmospheric dispersion through both the planetary boundary layer and the free troposphere. The new scheme greatly improves the performance of multiscale models, leading to better agreement with observed BaP concentrations in both source regions and remote regions Arctic , which cannot be achieved by less-elaborate degradation schemes deviations by multiple orders of magnitude. Our results highlight the importance of considering temperature and humidity effects on both the phase state of aerosol particles and the chemical reactivity of particulate air pollutants.
Cystic fibrosis transmembrane conductance regulator: temperature -dependent cysteine reactivity suggests different stable conformers of the conduction pathway. Cysteine scanning has been widely used to identify pore-lining residues in mammalian ion channels, including the cystic fibrosis transmembrane conductance regulator CFTR. These studies, however, have been typically conducted at room temperature rather than human body temperature.
Reports of substantial effects of temperature on gating and anion conduction in CFTR channels as well as an unexpected pattern of cysteine reactivity in the sixth transmembrane segment TM6 prompted us to investigate the effect of temperature on the reactivity of cysteines engineered into TM6 of CFTR. The results indicate that the reactivity of cysteines at three positions extracellular to the position of the accessibility barrier, , , and , is highly temperature -dependent.
However, the position of the accessibility barrier defined empirically by applying channel-permeant and channel-impermeant reagents to the extracellular aspect of the pore is not altered. The results illuminate previous scanning results and indicate that the assay temperature is a critical variable in studies designed to use chemical modification to test structural models for the CFTR anion conduction pathway.
High temperature interface superconductivity. High -T c superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals.
Highly reactive light-dependent monoterpenes in the Amazon. Jardine, A. Despite orders of magnitude difference in atmospheric reactivity and great diversity in biological functioning, little is known about monoterpene speciation in tropical forests. All 12 monoterpenes showed a mixing ratio peak in the upper canopy, with three demonstrating subcanopy peaks in 7 of 11 profiles. Leaf level emissions of highly reactive monoterpenes accounted for up to 1.
These results suggest that highly reactive monoterpenes play important antioxidant roles during photosynthesis in plants and serve as near-canopy sources of secondary organic aerosol precursors through atmospheric photooxidation via ozonolysis.
High temperature ion channels and pores. The present invention includes an apparatus, system and method for stochastic sensing of an analyte to a protein pore. The protein pore may be an engineer protein pore, such as an ion channel at temperatures above The analyte may be any reactive analyte, including chemical weapons, environmental toxins and pharmaceuticals.
The analyte covalently bonds to the sensor element to produce a detectable electrical current signal. Possible signals include change in electrical current. Detection of the signal allows identification of the analyte and determination of its concentration in a sample solution. Multiple analytes present in the same solution may also be detected. High temperature surface protection. Alloys of the MCrAlX type are the basis for high temperature surface protection systems in gas turbines.
M can be one or more of Ni, Co, or Fe and X denotes a reactive metal added to enhance oxide scale adherence. The selection and formation as well as the oxidation, hot corrosion and thermal fatigue performance of MCrAlX coatings are discussed. Coatings covered range from simple aluminides formed by pack cementation to the more advanced physical vapor deposition overlay coatings and developmental plasma spray deposited thermal barrier coatings. Advanced High Temperature Structural Seals. This program addresses the development of high temperature structural seals for control surfaces for a new generation of small reusable launch vehicles.
Successful development will contribute significantly to the mission goal of reducing launch cost for small, to pound payloads. Development of high temperature seals is mission enabling. For instance, ineffective control surface seals can result in high temperature F flows in the elevon area exceeding structural material limits. Longer sealing life will allow use for many missions before replacement, contributing to the reduction of hardware, operation and launch costs.
High temperature turbine engine structure. The disclosed joint is able to endure higher temperatures than previously possible, and aids in controlling heat transfer in the rotor member. Ceramic Adhesive for High Temperatures. New adhesive unaffected by extreme temperatures and vibrations. Assuring direct bonding of gap filters to tile sidewalls, adhesive obviates expensive and time-consuming task of removal, treatment, and replacement of tiles.
Development of high strength, high temperature ceramics. Improvement in the high -pressure turbopumps, both fuel and oxidizer, in the Space Shuttle main engine were considered. The operation of these pumps is limited by temperature restrictions of the metallic components used in these pumps.
Ceramic materials that retain strength at high temperatures and appear to be promising candidates for use as turbine blades and impellers are discussed. These high strength materials are sensitive to many related processing parameters such as impurities, sintering aids, reaction aids, particle size, processing temperature , and post thermal treatment. The specific objectives of the study were to: 1 identify and define the processing parameters that affect the properties of Si3N4 ceramic materials, 2 design and assembly equipment required for processing high strength ceramics, 3 design and assemble test apparatus for evaluating the high temperature properties of Si3N4, and 4 conduct a research program of manufacturing and evaluating Si3N4 materials as applicable to rocket engine applications.
High temperature structural insulating material. A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature above about The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about Newquist, Charles W. Successful development will contribute significantly to the mission goal of reducing launch cost for small, to lb payloads.
During the first phase of this program the existing launch vehicle control surface sealing concepts were reviewed, the aerothermal environment for a high temperature seal design was analyzed and a mock up of an arc-jet test fixture for evaluating seal concepts was fabricated. High temperature current mirror amplifier. A high temperature current mirror amplifier having biasing means in the transdiode connection of the input transistor for producing a voltage to maintain the base-collector junction reversed-biased and a current means for maintaining a current through the biasing means at high temperatures so that the base-collector junction of the input transistor remained reversed-biased.
For accuracy, a second current mirror is provided with a biasing means and current means on the input leg. Gallium phosphide high temperature diodes. High temperature C diodes for geothermal and other energy applications were developed. Diodes made from GaP should be usable to C. This process uses low vapor pressure Mg as a dopant which allows multiple boat growth in the same LPE run.
These LPE wafers were cut into die and metallized to make the diodes. High temperature life test data is presented which shows exceptional stability of the V-I characteristics. High temperature lightweight foamed cements. Cement slurries are disclosed which are suitable for use in geothermal wells since they can withstand high temperatures and high pressures.
The formulation consists of cement, silica flour, water, a retarder, a foaming agent, a foam stabilizer, and a reinforcing agent. A process for producing these cements is also disclosed. High temperature electronic gain device. An integrated thermionic device suitable for use in high temperature , high radiation environments. Cathode and control electrodes are deposited on a first substrate facing an anode on a second substrate.
The substrates are sealed to a refractory wall and evacuated to form an integrated triode vacuum tube. Temperature controlled high voltage regulator. A temperature controlled high voltage regulator for automatically adjusting the high voltage applied to a radiation detector is described. The regulator is a solid state device that is independent of the attached radiation detector, enabling the regulator to be used by various models of radiation detectors, such as gas flow proportional radiation detectors.
HIgh Temperature Photocatalysis over Semiconductors. Due in large part to in prevalence of solar energy, increasing demand of energy production from all sources , and the uncertain future of petroleum energy feedstocks, solar energy harvesting and other photochemical systems will play a major role in the developing energy market. This dissertation focuses on a novel photochemical reaction process: high temperature photocatalysis i.
J Intensive Care Soc. Published online Sep Author information Copyright and License information Disclaimer. Email: moc. Abstract The global incidence of invasive meningococcal disease due to serogroup W MenW has risen over the last decade. Keywords: Myocarditis, Neisseria meningitidis , serogroup W, bacteraemia, magnetic resonance imaging.
Case report A year-old woman presented to the Emergency Department by ambulance, with a 5-h history of progressively worsening pleuritic chest pain and dyspnoea. Open in a separate window. Figure 1. Discussion This case highlights the following: Patients with MenW infection may present to clinicians in atypical ways. Myopericarditis can, rarely, be a dominant feature of MenW sepsis. Consent This report is published with the written consent of the patient. References 1.
Global epidemiology of capsular group W meningococcal disease : multifocal emergence and persistence of hypervirulent sequence type ST clonal complex. Vaccine ; 34 : — Department of Health. Invasive meningococcal disease national surveillance report with a focus on MenW , www.
Tapsall J. Members of the National Neisseria Network of Australia. Antimicrobial susceptibility testing methods and practice with an Australian perspective. In: Merlino J. Meningococcal disease. N Engl J Med ; : — The changing and dynamic epidemiology of meningococcal disease.
Vaccine ; 30 : B26—B Increase in meningococcal serogroup W disease, Victoria, Australia, Emerg Infect Dis ; 22 : — Presentation with gastrointestinal symptoms and high case fatality associated with group W meningococcal disease MenW in teenagers, England, July to January Euro Surveill ; 21 : 11— Increase in endemic Neisseria meningitidis capsular group W sequence type 11 complex associated with severe invasive disease in England and Wales.
Clin Infect Dis ; 60 : — Hajj-associated outbreak strain of Neisseria meningitidis serogroup W estimates of the attack rate in a defined population and the risk of invasive disease developing in carriers. Clin Infect Dis ; 36 : — Meningococcal disease, a clinical and epidemiological review. Asian Pac J Trop Med ; 10 : — Clinical characteristics and public health management of invasive meningococcal group W disease in the East Midlands region of England, United Kingdom, to Euro Surveill ; 21 : 12— The role of particular strains of Neisseria meningitidis in meningococcal arthritis, pericarditis, and pneumonia.
Clin Infect Dis ; 37 : — Australian Meningococcal Surveillance Programme annual report, Duration of hypotension before initiation of effective antimicrobial therapy is the critical determinant of survival in human septic shock. Crit Care Med ; 34 : — Myopericarditis as an initial presentation of meningococcemia. Unusual manifestation of infection with serotype W Am J Med ; 82 : — Myopericarditis with cardiac tamponade caused by Neisseria meningitidis serogroup W Frequency of myocarditis in cases of fatal meningococcal infection in children: observations on 31 cases studied at autopsy.
Rev Soc Bras Med Trop ; 32 : — Acute right-sided heart failure caused by Neisseria meningitidis. J Clin Microbiol ; 51 : — Neisseria meningitidis. Clonal expansion of new penicillin-resistant clade of Neisseria meningitidis serogroup W clonal complex 11, Australia.
Emerg Infect Dis ; 23 : — Invasive meningococcal disease-induced myocarditis in critically ill adult patients: initial presentation and long-term outcome. Intensive Care Med ; — Importance of early diagnosis and therapy of acute meningococcal myocarditis: a case report with review of literature.
Am J Ther ; 12 : — Support Center Support Center.
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