- Energy Find out what NIST is currently working on in Energy.
Jack Pevenstein
Technology Partnership Office
301-975-5519
nisttech@nist.gov
100 Bureau Drive, M/S 2200
Gaithersburg, MD, 20899
The method of the invention identifies damage to an in-service conductor associated with the delivery (transmission and distribution) of electric power. Electro-magnetic acoustic energy is generated in an in-service conductor associated with the delivery of electric power. Corresponding return electro-magnetic acoustic energy is then measured. Features are then extracted from the return electro-magnetic acoustic energy to characterize damage to the in-service conductor. The features may be extracted through a variety of signal processing techniques, such as wavelet signal processing. The extracted features may be classified using a neural network, fuzzy logic, or a combination of both.
A ultrasonic method for measuring wall thickness and detecting material flaws in natural-gas pipelines, risers, and similar structures. The method is inherently suitable for the task, because it relies on the use of the natural gas as the coupling fluid for transmitting the probing ultrasonic signals into and out of the pipe wall. Furthermore, the method facilitates the operation of the inspection from the inside of the pipe. An experimental apparatus used to demonstrate the technical feasibility of this approach and provide experimental and theoretical evidence that support the claims is described. Significantly, it is shown that by the use of a diplexer, the same transducer can be used to generate and detect the probing ultrasonic signals. The same configuration is used in commercial ultrasonic inspection of oil pipelines where oil is the coupling fluid; but until now this method could not be used in natural gas pipelines due to the low specific acoustic impedance of natural gas.
A thin-film thermocouple is provided which can be used at temperature of up to 900° C. The thin-film thermocouple includes: a silicon substrate; an SiO2 diffusion barrier layer formed on the substrate; a titanium oxide adhesion layer formed on the diffusion barrier layer; a palladium thin film formed on the diffusion barrier layer; and a platinum thin film formed on the diffusion barrier layer and overlapping a portion of the palladium thin film to form a thermocouple junction.
Multilayer, thin film multijunction integrated micropotentiometers are formed in an integral multifilm membrane form over a through opening in a nonmagnetic, dielectric substrate. Through the use of conventional photolithographic and etching techniques, integrated structures are formed to include either single elongate heater elements, bifilar heater elements, or trifilar heater elements with multiple return paths. Multijunction thermopiles and resistors are formed with the heater. The individual layers of silicon oxide or silicon nitride, are formed with conventional chemical vapor deposition, sputtering and other known techniques.
A pyroelectric detector with significantly reduced microphonic noise sensitivity that includes a pyroelectric detector element constructed from a z-cut LiNbO3 or LiTaO3 electret. Selective domain reversal is accomplished in the electret by applying an electric field. Electrodes are attached to either surface of the electret spanning the domain reversed region and a portion of the original domain region to create areas of equal and opposite sensitivity. The detector is mounted in an electrically grounded container or housing. The detector may also be constructed having multiple detector regions to accommodate resonant acoustic frequencies of the electret, to function as a position sensor, or both. In other words, the position sensor has multiple domain regions that also accommodate acoustic frequencies. The detector may also be constructed having domain reversed regions placed on the electret in a periodic pattern having a geometry and spacing that is related to the acoustic impulse response of the electret. Needle domains may also be interspersed in portions or throughout the electret to scatter acoustic waves and thereby reduce acoustic noise. Multiple detectors can be produced in a simple and inexpensive manner using shadow masking techniques.
A method for the removal of carbonyl sulfide from liquefied petroleum is disclosed. Removal of carbonyl sulfide is accomplished by contacting a liquid petroleum gas stream containing a carbonyl sulfide as an impurity with a calixarene complexing agent as the principal agent for the removal of the carbonyl sulfide.
This invention provides a mechanical support for a two-pill Adiabatic Demagnetization Refrigerator (ADR). The support utilizes a suspension of the two pills from one side of the magnet bore only. In the two pill ADR, the thermal ground is at 4K, a guard pill positioned in the front of the bore cools to 1K and a base pill positioned in the back of the bore cools to 50-100 mk. A connector rod of the base pill traverses the guard pill, and connector rods to both the guard pill and base pill exit through the front aperture. A preferred embodiment of the two-pill support for the front loaded magnet bore utilizes planar support modules comprising three members connected by Kevlar strings. Each member is thermally connected either to one of the pills or to thermal ground. The ground member, the guard member and the base member of the support module are strung with Kevlar threads, such that the base member is suspended only from the guard member, and the guard member only from the ground member. These planar support modules can be aligned and assembled prior to use in an assembly jig. The final assembly of the two-pill support structure using planar support modules is easy and fast.
A system for heating water using solar energy comprises a photovoltaic array, a water heater comprising a variable resistive load, and a controller for varying either the load characteristics of the resistive load or the power generating characteristics of the photovoltaic array, or both, to ensure maximum power transfer efficiency.
Multi-layer transition-edge sensors (TES) having improved performance, a method for preparing them and methods of using them. Specifically, the improvement lies in providing normal metal strips along the edges of the superconducting and normal metal layers parallel to the current flow in the TES during operation. These strips (referred to as "banks") provide for both improved detector performance and improved detector robustness against corrosion. This improvement is an important advance particularly for TES-based microcalorimeter detectors. The improved TESs also have many other applications based on the very precise thermometer function achieved by the TES.
Typical applications for switching power devices (e.g., IGBT or Power MOSFET) require reverse conduction for rectification or clamping by either an internal or external diode. Because Power MOSFETs have an inherent PiN diode within the structure, this internal diode must either be made to work effetely for the rectification and clamping, or must be bypassed by an external diode. Because the inherent internal PiN diode results in majority carrier injection from the drain-body junction (PN junction at Body-to-Drift-Layer interface) it has slow reverse recovery time and may result in SiC crystal degradation. The concept of inclusion of reverse conducting SIR junction shunts provides substantial benefits by: 1) bypassing current flow from the inherent internal drain-body junction preventing it from injecting majority carriers and thus preventing slow reverse recovery and crystal degradation, and 2) enabling current to flow for voltages lower than the drain-body junction built in potential (e.g., approximately 3 V for SiC) and thus provides lower on-state losses than a PiN diode for the lower current range condition.
A method of harvesting carbon nanotubes (CNTs) is provided. According to this method, CNT bundles, comprising CNTs associated with metallic catalysts and having amorphous carbon coatings are agitated in an aqueous liquid containing a dispersant with free-flowing grit particles to disassociate the CNTs from the metallic catalysts, remove the amorphous carbon of the amorphous carbon coatings and shorten the CNTs via shearing.
A National Institute of Standards and Technology (NIST) researcher has come up with a method designed to improve the energy efficiency of water chillers that cool the nation’s large commercial buildings. The NIST method, if confirmed through experiments with full-scale chiller systems, could save as much as 1 percent of the 320 billion kWh of electricity used annually by chillers or an equivalent 5.5 million barrels of oil per year, according to Mark Kedzierski, the NIST mechanical engineer who developed the technique.
A method and apparatus for detecting slow neutrons by monitoring Lyman alpha radiation produced by the .sup.3He(n,tp) nuclear reaction induced by neutrons incident on a gas cell containing .sup.3He or a mixture of .sup.3He and other atoms and/or molecules. Such a method and/or apparatus includes the use of, for example, liquid .sup.3He and .sup.4He mixtures as a scintillation counter for the sensitive detection of neutrons using Lyman alpha radiation produced by the .sup.3He(n,tp) reaction. The radiation can be detected with high efficiency with an appropriate photo-detector, or alternatively, it can be converted to radiation at longer wavelength by absorption in scintillation materials, with the radiation channeled to a photodetector. Because of the simplicity of the system and the fact that the radiation production mechanisms can be measured and/or calculated independently, the method and/or apparatus also has the potential for service as a calculable absolute detector.