5 research outputs found
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Linescan Camera System for 100% Moisture Measurement
Lawrence Livermore National Laboratory (LLNL), in collaboration with ABB Industrial Systems, and under the sponsorship of the Department of Energy's (DOE) Office of Industrial Technologies (OIT), has developed a new method for measuring the moisture content of a paper web process on-line with 100% coverage of the sheet. The method uses InGaAs linear arrays with associated optics and electronics to continuously image the full width of the web and measure transmitted light at 1.45{micro} and another suitable reference wavelength between 1{micro} and 1.6{micro}. The method could also be used to measure paper basis weight, in addition to moisture, by adding additional hardware and optics to measure a third wavelength at 1.57{micro}. A patent (USP: 6355931), entitled ''System and method for 100% moisture and basis weight measurement of moving paper'', was granted by the US Patent Office on March 12, 2002 for this invention. A proof-of-concept prototype system was also developed and tested on several occasions at ABB's sensors development facility in Columbus, Ohio. Based on current experimental results, the system seems particularly suitable for detecting moisture variation on a paper web for medium and heavy weight products at the dry end as well as the press section of the machine. The prototype system was scheduled to be tested at a paper mill in the fall of 2001. The test had to be canceled as ABB was unable to provide the required field support for the test due to restructuring and down-sizing of their R&D organization
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Performance of a 500 watt Nd:GGG zigzag slab oscillator
Realization of practical multi-kilowatt Nd:garnet lasers will require the scale-up of crystal dimensions as well as more powerful pumping sources. A high average power zigzag slab crystal amplifier testing facility has been established at LLNL which employs two 100 kW{sub e} vortex stabilized arc lamps, cooled reflectors and a cooled, spectrally filtered, crystal slab mounting fixture. The operational characteristics of the first crystal laser to be tested in this setup, a Nd:GGG zigzag oscillator, are presented. A Nd:GGG crystal of dimensions 18 {times} 7 {times} 0.5 cm{sup 3}, doped at 2 {times} 10{sup 20} cm{sup {minus}3} Nd{sup 3+} atomic density, was pumped by up to 40 kW of filtered argon line emission. A small-signal single pass gain (losses excluded) of 1.09 was measured with a probe laser when the DC input to the lamps was 43 kW{sub e}. Our power supply was then modified to operate in a pulsed mode and provided one to three milliseconds pulses at 120 Hz. An average optical output power of 490 watts was obtained at a lamp input power of 93 kW{sub e} in an unoptimized resonator. The laser output power declined after a few tens of seconds since the slab tips were not properly cooled. A birdhouse specular lamp reflector and a contoured diffuse reflector were tested; in both cases the pump illuminated crystal surface was smaller than the total crystal face area. Fluorescence imaging of the zigzag amplifier's output aperture registered a smoother, more uniform pumping profile when the diffuse reflector was used. Uniformity of pumping results in decreased resonator loss and yields higher laser output power. Thermo-optic distortions observed in these preliminary tests are analyzed with the aid of computer simulations of the thermal fields, stresses, and surface displacements of our crystal slab. 3 refs., 12 figs
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Pulse-power circuit diagnostics for the Nova laser
The Nova laser will have a large pulse power system for driving laser amplifiers, incorporating approximately 1600 flashlamp circuits. An automated system has been designed for diagnosing the condition of these flashlamp circuits. It records digitized circuit current waveforms and detects current excursions above a given threshold. In addition, it is able to fire flashlamps at a low energy to ascertain the health of the system. Data from this system can be ploted for inspection by the operator, analyzed by the computer system and archived for future reference
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Microwave Hematoma Detector for the Rapid Assessment of Head Injuries
A non-invasive microwave device for the detection of epi/subdural hemorrhaging (hematoma) is under current development. The final device will be highly portable and allow real time assessment of head injuries, thereby satisfying early detection needs of the field technician as well as providing a tool for repetitious monitoring of high-risk individuals. The device will adopt the advanced technology of micropower impulse radar (MIR) which is a state of the art low cost ultra wide band (UWB) microwave radar developed here at LLNL. It will consist of a MIR transmitting and receiving module, a computer based signal processing module, and a device-to-patient signal coupling module--the UWB antenna. The prototype design is being guided by the needs of the patient and the practitioner along with the prerequisites of the technology including issues such as the specificity of the device, efficacy of diagnosis, accuracy, robustness, and patient comfort. The prototype development follows a concurrent approach which .includes experiments designed to evaluate requirements of the radar and antenna design, phantom development to facilitate laboratory investigations, and investigation into the limits of adapting pre-existing non-medical MIR devices to medical applications. This report will present the accomplishments and project highlights to date in the fiscal year 1999. Future project projections will also be discussed