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July/August 2002

The Laboratory
in the News

Commentary by
C. K. Chou

The Outlook Is for Warming, with Measurable Local Effects

How Metals Fail

Converting Data to Decisions

Knowing the Enemy, Knowing the Threat





Steven L. Hunter
Self Adjusting Inclinometer
U.S. Patent 6,349,477 B1
February 26, 2002
An inclinometer using synchronous demodulation for high resolution and electronic offset adjustment provides a wide dynamic range without any moving components. A device encompassing a tiltmeter and accompanying electronic circuitry provides quasi-leveled tilt sensors that detect highly resolved tilt change without signal saturation.

Steven R. Visuri, Luiz B. Da Silva, Peter M. Celliers, Richard A. London, William Benett, Kathryn Broughton, Victor Esch
Opto-Acoustic Recanilization Delivery System
U.S. Patent 6,368,318 B1
April 9, 2002
Fiber-delivered laser pulses emulsify a thrombus by mechanical stresses that include a combination of pressure, tension, and shear stress. Laser radiation is delivered to the locality of a thrombus, and the radiation is absorbed by blood, blood clots, or other materials present. The combination of a leading pressure wave and subsequent vapor bubble causes efficient emulsification of the thrombus. Operating the laser in a low-average-power mode alleviates potential thermal complications. The laser is operated in a high-repetition-rate mode to take advantage of ultrasound frequency effects of thrombus dissolution as well as to decrease the total procedure time. The device includes optical fibers surrounding a lumen intended for flow of a cooling agent. The fibers may be arranged concentrically around the lumen to deliver radiation and heat over as large an area as possible. An alternative design approach incorporates the optical fibers into the wall of the guiding catheter and uses the catheter lumen as the cooling channel. An eccentric tip enables rotation of the device to address all parts of the vasculature. The eccentricity can be provided via a variety of means, including spring dip, balloon, and protrusion.

Bernardino M. Penetrante, George E. Vogtlin, Bernard T. Merritt, Raymond M. Brusasco
Plasma-Assisted Catalytic Storage Reduction System
U.S. Patent 6,374,595 B1
April 23, 2002
A two-stage method for reducing oxides of nitrogen (NOx) in an oxygen-rich engine exhaust comprises a plasma oxidative stage and a storage reduction stage. The first stage employs a nonthermal plasma treatment of NOx gases in an oxygen-rich exhaust and is intended to convert nitrogen oxide (NO) to nitrogen dioxide (NO2) in the presence of oxygen (O2) and hydrocarbons. The second stage employs a lean NOx trap to convert such NO2 to environmentally benign gases that include nitrogen (N2), carbon dioxide (CO2), and water (H2O). By preconverting NO to NO2 in the first stage with a plasma, the efficiency of the second stage for NOx reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber in which a nonthermal plasma converts NO to NO2 in the presence of O2 and hydrocarbons such as propene. A flow of such hydrocarbons (CxHy) is input usually from a second pipe into at least a portion of the first chamber. The NO2 from the plasma treatment proceeds to a storage reduction catalyst (lean NOx trap) that converts NO2 to N2, CO2, and H2O and includes a nitrate-forming catalytic site. The hydrocarbons and NOx are simultaneously reduced while passing through the lean NOx trap catalyst. The method allows for enhanced NOx reduction in vehicular engine exhausts, particularly those having relatively high sulfur contents.

Greg C. Burnett, John F. Holzrichter, Lawrence C. Ng
System and Method for Characterizing Voiced Excitations of Speech and Acoustic Signals, Removing Acoustic Noise from Speech, and Synthesizing Speech
U.S. Patent 6,377,919 B1
April 23, 2002
Low-power electromagnetic waves are used to detect motions of vocal tract tissues of the human speech system before, during, and after voiced speech. A voiced excitation function is derived. The excitation function provides speech production information to enhance speech characterization and to enable noise removal from human speech.

Timothy P. Weihs, Troy W. Barbee, Jr.
Low Resistance Barrier Layer for Isolating, Adhering, and Passivating Copper Metal in Semiconductor Fabrication
U.S. Patent 6,380,627 B1
April 30, 2002
Cubic or metastable cubic refractory metal carbides act as barrier layers to isolate, adhere, and passivate copper in semiconductor fabrication. One or more barrier layers of the metal carbide are deposited in conjunction with copper metallizations to form a multilayer characterized by a cubic crystal structure with a strong (100) texture. Suitable barrier layer materials include refractory transition metal carbides such as vanadium carbide, niobium carbide, tantalum carbide, chromium carbide, tungsten carbide, and molybdenum carbide.

Steven L. Hunter
Rotational Rate Sensor
U.S. Patent 6,382,025 B1
May 7, 2002
A rate sensor for angular/rotational acceleration includes a housing that defines a fluid cavity that is essentially completely filled with an electrolyte fluid. Within the housing, such as a toroid, ions in the fluid are swept during the movement from an excitation electrode toward one of two output electrodes to provide a signal for directional rotation. One or more ground electrodes within the housing serve to neutralize ions, thus preventing any effect at the other output electrode.

Paula A. W. Krauter, Gordon W. Krauter
Water Treatment Process and System for Metals Removal Using Saccharomyces Cerevisiae
U.S. Patent 6,383,388 B1
May 7, 2002
A process and a system for removing metals from groundwater or soil by bioreducing or bioaccumulating the metals with metal-tolerant microorganisms Saccharomyces cerevisiae. S. cerevisiae are tolerant to the metals, able to bioreduce them to a less toxic state, and accumulate them. The process and the system are useful for removal or substantial reduction of levels of chromium, molybdenum, cobalt, zinc, nickel, calcium, strontium, mercury, and copper in water.



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