Chemical engineering design of CO oxidation catalysts

NASA Technical Reports Server (NTRS)

Herz, Richard K.

1987-01-01

How a chemical reaction engineer would approach the challenge of designing a CO oxidation catalyst for pulsed CO2 lasers is described. CO oxidation catalysts have a long history of application, of course, so it is instructive to first consider the special requirements of the laser application and then to compare them to the characteristics of existing processes which utilize CO oxidation catalysts. All CO2 laser applications require a CO oxidation catalyst with the following characteristics: (1) active at stoichiometric ratios of O2 and CO, (2) no inhibition by CO2 or other components of the laser environment, (3) releases no particulates during vibration or thermal cycling, and (4) long lifetime with a stable activity. In all applications, low consumption of power is desirable, a characteristic especially critical in aerospace applications and, thus, catalyst activity at low temperatures is highly desirable. High power lasers with high pulse repetition rates inherently require circulation of the gas mixture and this forced circulation is available for moving gas past the catalyst. Low repetition rate lasers, however, do not inherently require gas circulation, so a catalyst that did not require such circulation would be favorable from the standpoint of minimum power consumption. Lasers designed for atmospheric penetration of their infrared radiation utilize CO2 formed from rare isotopes of oxygen and this application has the additional constraint that normal abundance oxygen isotopes in the catalyst must not exchange with rare isotopes in the gas mixture.

Laser beam pulse formatting method

DOEpatents

Daly, T.P.; Moses, E.I.; Patterson, R.W.; Sawicki, R.H.

1994-08-09

A method for formatting a laser beam pulse using one or more delay loops is disclosed. The delay loops have a partially reflective beam splitter and a plurality of highly reflective mirrors arranged such that the laser beam pulse enters into the delay loop through the beam splitter and circulates therein along a delay loop length defined by the mirrors. As the laser beam pulse circulates within the delay loop a portion thereof is emitted upon each completed circuit when the laser beam pulse strikes the beam splitter. The laser beam pulse is thereby formatted into a plurality of sub-pulses. The delay loops are used in combination to produce complex waveforms by combining the sub-pulses using additive waveform synthesis. 8 figs.

In Vivo Fluorescence Imaging and Tracking of Circulating Cells and Therapeutic Nanoparticles

NASA Astrophysics Data System (ADS)

Markovic, Stacey

Noninvasive enumeration of rare circulating cells in small animals is of great importance in many areas of biomedical research, but most existing enumeration techniques involve drawing and enriching blood which is known to be problematic. Recently, small animal "in vivo flow cytometry" (IVFC) techniques have been developed, where cells flowing through small arterioles are counted continuously and noninvasively in vivo. However, higher sensitivity IVFC techniques are needed for studying low-abundance (<100/mL) circulating cells. To this end, we developed a macroscopic fluorescence imaging system and automated computer vision algorithm that allows in vivo detection, enumeration and tracking of circulating fluorescently labeled cells from multiple large blood vessels in the ear of a mouse. This technique ---"computer vision IVFC" (CV-IVFC) --- allows cell detection and enumeration at concentrations of 20 cells/mL. Performance of CV-IVFC was also characterized for low-contrast imaging scenarios, representing conditions of weak cell fluorescent labeling or high background tissue autofluorescence, and showed efficient tracking and enumeration of circulating cells with 50% sensitivity in contrast conditions degraded 2 orders of magnitude compared to in vivo testing supporting the potential utility of CV-IVFC in a range of biological models. Refinement of prior work in our lab of a separate rare-cell detection platform - "diffuse fluorescence flow cytometry" (DFFC) --- implemented a "frequency encoding" scheme by modulating two excitation lasers. Fluorescent light from both lasers can be simultaneously detected and split by frequency allowing for better discrimination of noise, sensitivity, and cell localization. The system design is described in detail and preliminary data is shown. Last, we developed a broad-field transmission fluorescence imaging system to observe nanoparticle (NP) diffusion in bulk biological tissue. Novel, implantable NP spacers allow controlled, long-term release of drugs. However, kinetics of NP (drug) diffusion over time is still poorly understood. Our imaging system allowed us to quantify diffusion of free dye and NPs of different sizes in vitro and in vivo. Subsequent analysis verified that there was continuous diffusion which could be controlled based on particle size. Continued use of this imaging system will aid optimization of NP spacers.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoder Jr, Graydon L; Heatherly, Dennis Wayne; Williams, David F

A small molten fluoride salt experiment has been constructed and tested to develop experimental techniques for application in liquid fluoride salt systems. There were five major objectives in developing this test apparatus: Allow visual observation of the salt during testing (how can lighting be introduced, how can pictures be taken, what can be seen) Determine if IR photography can be used to examine components submerged in the salt Determine if the experimental configuration provides salt velocity sufficient for collection of corrosion data for future experimentation Determine if a laser Doppler velocimeter can be used to quantify salt velocities. Acquire naturalmore » circulation heat transfer data in fluoride salt at temperatures up to 700oC All of these objectives were successfully achieved during testing with the exception of the fourth: acquiring velocity data using the laser Doppler velocimeter. This paper describes the experiment and experimental techniques used, and presents data taken during natural circulation testing.« less

Laser beam pulse formatting method

DOEpatents

Daly, Thomas P.; Moses, Edward I.; Patterson, Ralph W.; Sawicki, Richard H.

1994-01-01

A method for formatting a laser beam pulse (20) using one or more delay loops (10). The delay loops (10) have a partially reflective beam splitter (12) and a plurality of highly reflective mirrors (14) arranged such that the laser beam pulse (20) enters into the delay loop (10) through the beam splitter (12) and circulates therein along a delay loop length (24) defined by the mirrors (14). As the laser beam pulse (20) circulates within the delay loop (10) a portion thereof is emitted upon each completed circuit when the laser beam pulse (20) strikes the beam splitter (12). The laser beam pulse (20) is thereby formatted into a plurality of sub-pulses (50, 52, 54 and 56). The delay loops (10) are used in combination to produce complex waveforms by combining the sub-pulses (50, 52, 54 and 56) using additive waveform synthesis.

Measurement of Rubidium Number Density Under Optically Thick Conditions

DTIC Science & Technology

2010-11-15

for efficient, high-power laser systems . While these alkali metals offer great promise, there are several issues which need to be resolved. Two such...circulator. The pressure and composition of the diluent within the heat pipe could also be adjusted using the attached gas handling system . The gas...handling system consisted of a vacuum pump, 10 Torr and 1000 Torr baratrons, various valves and a line going to a regulated gas cylinder. The second

Photoacoustic imaging of single circulating melanoma cells in vivo

NASA Astrophysics Data System (ADS)

Wang, Lidai; Yao, Junjie; Zhang, Ruiying; Xu, Song; Li, Guo; Zou, Jun; Wang, Lihong V.

2015-03-01

Melanoma, one of the most common types of skin cancer, has a high mortality rate, mainly due to a high propensity for tumor metastasis. The presence of circulating tumor cells (CTCs) is a potential predictor for metastasis. Label-free imaging of single circulating melanoma cells in vivo provides rich information on tumor progress. Here we present photoacoustic microscopy of single melanoma cells in living animals. We used a fast-scanning optical-resolution photoacoustic microscope to image the microvasculature in mouse ears. The imaging system has sub-cellular spatial resolution and works in reflection mode. A fast-scanning mirror allows the system to acquire fast volumetric images over a large field of view. A 500-kHz pulsed laser was used to image blood and CTCs. Single circulating melanoma cells were imaged in both capillaries and trunk vessels in living animals. These high-resolution images may be used in early detection of CTCs with potentially high sensitivity. In addition, this technique enables in vivo study of tumor cell extravasation from a primary tumor, which addresses an urgent pre-clinical need.

Laser Gyro Attitude Control System Feasibility Study.

DTIC Science & Technology

1987-04-24

GYROS (Distinguishable by method used to circumvent lock-in phenomenon) M ECHANICAL DITHER ,. MAGNETIC MIRROR DILAG (MULTI-OSCILLATOR) Figure 1...by a multiple transit of a light beam within a closed optical cavity (a three- mirror system). The beam traverses the cavity continuously; after each...circulation a small fraction of the beam intensity is output at one of the mirrors . Each transit incurs a phase % %0 ? % o I" us ol *..~% % %~*,~*)*f

Immunodeficiency and laser magnetic therapy in urology

NASA Astrophysics Data System (ADS)

Maati, Moufagued; Rozanov, Vladimir V.; Avdoshin, V. P.

1996-11-01

The importance of immunodeficiency problem has increased last time not only due to AIDS appearance, but also to a great extent as a result of the development and active practical use of the methods of immunology parameters investigations. Al great pharmaceutical firms are organizing the process of creating the drugs, influencing on the different phases of immunity, but unfortunately, the problem of their adverse effect and connected complications is till today a milestone. A great number of investigations, proving a good effect of laser-magnetic therapy concerning immune system have been done today. There is, in particular, changing of blood counts and immunologic tests after intravenous laser irradiation of blood. Intravenous laser irradiation of blood results in increasing of lymphocytes, T-immuno stimulation, stabilization of t-lymphocyte subpopulation, increasing of t-lymphocyte helper activity and decreasing of suppressor one.Under this laser action number of circulating immune complexes is decreased, and blood serum bactericide activity and lisozyme number are increased.

Skin permeation and retention of topical bead formulation containing tranexamic acid.

PubMed

Vijayakumar, Ajay; Baskaran, Rengarajan; Yoo, Bong Kyu

2017-02-01

The objective of this study is to develop a topical bead formulation of tranexamic acid (TA) which can be used concomitantly with laser treatment. The bead formulation of TA (TAB) was successfully prepared by fluidized bed drying method. Physicochemical properties of the TAB were evaluated in terms of chemical stability of TA and differential scanning calorimetry. TA in the bead was stable up to six months at 25°C and existed as amorphous state. In vitro skin permeation and in vivo skin retention of TA in the beads were significantly higher compared to a commercial product. When the bead was dissolved into distilled water and applied concomitantly with laser treatment, the amount of TA retained in the skin in the in vivo study was inversely proportional to the energy levels of laser treatment, indicating absorption into subcutaneous tissue and drainage to systemic circulation. Therefore, when laser treatment is used concomitantly with TAB, energy level should be very carefully monitored to avoid possible adverse events associated with systemic side effects of TA.

Laser-induced disruption of systemically administered liposomes for targeted drug delivery

NASA Astrophysics Data System (ADS)

Mackanos, Mark A.; Larabi, Malika; Shinde, Rajesh; Simanovskii, Dmitrii M.; Guccione, Samira; Contag, Christopher H.

2009-07-01

Liposomal formulations of drugs have been shown to enhance drug efficacy by prolonging circulation time, increasing local concentration and reducing off-target effects. Controlled release from these formulations would increase their utility, and hyperthermia has been explored as a stimulus for targeted delivery of encapsulated drugs. Use of lasers as a thermal source could provide improved control over the release of the drug from the liposomes with minimal collateral tissue damage. Appropriate methods for assessing local release after systemic delivery would aid in testing and development of better formulations. We use in vivo bioluminescence imaging to investigate the spatiotemporal distribution of luciferin, used as a model small molecule, and demonstrate laser-induced release from liposomes in animal models after systemic delivery. These liposomes were tested for luciferin release between 37 and 45 °C in PBS and serum using bioluminescence measurements. In vivo studies were performed on transgenic reporter mice that express luciferase constitutively throughout the body, thus providing a noninvasive readout for controlled release following systemic delivery. An Nd:YLF laser was used (527 nm) to heat tissues and induce rupture of the intravenously delivered liposomes in target tissues. These data demonstrate laser-mediated control of small molecule delivery using thermally sensitive liposomal formulations.

Polarized 3He gas circulating technologies for neutron analyzers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watt, David W.

We outline our project to develop a circulating polarized helium-3 system for developing of large, quasi-continuously operating neutron analyzers. The project consisted of four areas: 1) Development of robust external cavity narrowed diode laser output with spectral line width < 0.17 nm and power of 2000 W. 2) Development of large glass polarizing cells using cell surface treatments to obtain long relaxation lifetimes. 3) Refinements of the circulation system with an emphasis on gas purification and materials testing. 4) Design/fabrication of a new polarizer system. 5) Preliminary testing of the new polarizer. 1. Developed Robust High-Power Narrowed Laser The opticalmore » configuration of the laser was discussed in the proposal and will be reviewed in the body of this report. The external cavity is configured to mutually lock the wavelength of five 10-bar laser stacks. All the logistical milestones were been met and critical subsystems- laser stack manifold and power divider, external laser cavity, and output telescope- were assembled and tested at low power. Each individual bar is narrowed to ~0.05 nm; when combined the laser has a cumulative spectral width of 0.17 nm across the entire beam due to variations of the bars central wavelength by +/- 0.1 nm, which is similar to that of Volume Bragg Grating narrowed laser bars. This configuration eliminates the free-running “pedestal” that occurs in other external cavity diode lasers. The full-scale laser was completed in 2016 and was used in both the older and newer helium polarizers. This laser was operated at 75% power for periods of up to 8 hours. Once installed, the spectrum became slightly broader (~.25 nm) at full power; this is likely due to very slight misalignments that occurred during handling. 2. Developed the processes to create uniform sintered sol-gel coatings. Our work on cell development comprised: 1) Production of large GE180 cells and explore different means of cell preparation, and 2) Development of apply sol-gel coatings to the interior of both borosilicate and aluminosilicate cells. We applied six sol-gel coatings. By modifying the mixture and developing procedures to drain and dry the cell, we produced visually uniform coatings on the interior of the cells. We now have perfected that process as described below in our report. We were able to accelerate the testing of cells using an ex situ method that avoids installing each cell into a polarizer. In the project’s last year, we conducted 38 external tests of 8 different cells. We also installed two sol-gel coated cells in our polarizers. We created cell with long ex situ relaxation lifetimes, one of which exceeded 40 hours. However, when installed in the polarizer the measured lifetime is 8 hours or less. 3. Demonstrated cycling of polarized gas and ex situ cell testing We are now cycling polarized gas from the polarizer to glass vessels and back. This has allowed us, for the first time, to make ex situ T1 measurements of polarizing cells without installing them into the polarizer itself. This has greatly improved our productivity in producing cells and evaluating our cell preparation processes. We continued development of the gas handling system in parallel with fabricating new polarizer. The integrated system was tested by the end of 2016. We now regularly cycle gas into and out of the polarizer. 4. Completed new polarizer infrastructure and control systems. We completed the new polarizer infrastructure in November 2016. The polarizer subsystems are 1) the frame, 2) the oil flow system, 3) the gas handling system, 4) the pressure vessel, with embedded solenoid, 5) cell mounting hardware with heat spreaders, and 6) electrical power and instrumentation. 5. Carried out initial tests of polarizer. We completed initial testing of the polarizer in April and May of 2017. These tests were carried out for periods up to 6 hours with laser power between 750 and 1300 Watts. The laser performed well and the polarization with asymptotic to 45 percent, which was below expectations. This low value resulted from a stationary thermal inversion in the cell that caused most of the laser power to be absorbed near the laser inlet window and deprived the lower portions of the cell of pumping laser light. Possible solutions to this problem include enhanced cooling of the cell near the laser entry and slight detuning of the laser. 6. Ongoing work. Our polarizer development efforts are ongoing to pursue our interest in neutron analyzers, nuclear targets, and providing helium for medical imaging. Current tests in the pipeline include: 1. Testing cooling enhancements to improve laser penetration of spectrally narrow lasers; 2. Testing of a cell with isolation valves that minimizes diffusive contact with gas handling hardware during polarization; 3. Testing of smaller hybrid cells with reduced alkali loading; 4. Producing polarized helium-3 for MRI imaging at the University of Missouri.« less

Blood flow measurement in extracorporeal circulation using self-mixing laser diode

NASA Astrophysics Data System (ADS)

Cattini, Stefano; Norgia, Michele; Pesatori, Alessandro; Rovati, Luigi

2010-02-01

To measure blood flow rate in ex-vivo circulation, we propose an optical Doppler flowmeter based on the self-mixing effect within a laser diode (SM-LD). Advantages in adopting SM-LD techniques derive from reduced costs, ease of implementation and limited size. Moreover, the provided contactless sensing allows sensor reuse, hence further cost reduction. Preliminary measurements performed on bovine blood are reported, thus demonstrating the applicability of the proposed measurement method.

Compact Storage Ring for an X-Ray Source

NASA Astrophysics Data System (ADS)

Ovchinnikova, L.; Shvedunov, V.; Ivanov, K.

2017-12-01

We propose a new design of a compact storage ring for a source of X-ray radiation on the basis of reverse Thomson scattering of laser radiation by electrons with the energy of 35-50 MeV, which has small number of optical elements and a significant clear space for the placement of a beam injection-extraction system and a RF cavity. The original laser cavity layout has been considered. The ring dynamic aperture after correction of chromaticity and a second-order dispersion function is sufficient for the injection and stable circulation of an electron bunch in the ring.

Generating and manipulating quantized vortices on-demand in a Bose-Einstein condensate: A numerical study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gertjerenken, B.; Kevrekidis, P. G.; Carretero-González, R.

Here, we numerically investigate an experimentally viable method for generating and manipulating on-demand several vortices in a highly oblate atomic Bose-Einstein condensate (BEC) in order to initialize complex vortex distributions for studies of vortex dynamics. The method utilizes moving laser beams to generate, capture, and transport vortices inside and outside the BEC. This methodology is examined in detail and shows a wide parameter range of applicability for the prototypical two-vortex case, as well as case examples of producing and manipulating several vortices for which there is no net circulation, corresponding to equal numbers of positive and negative circulation vortices, andmore » cases for which there is one net quantum of circulation. We also find that the presence of dissipation can help stabilize the pinning of the vortices on their respective laser beam pinning sites. Finally, we illustrate how to utilize laser beams as repositories that hold large numbers of vortices and how to deposit individual vortices in a sequential fashion in the repositories in order to construct superfluid flows about the repository beams with several quanta of circulation.« less

Generating and manipulating quantized vortices on-demand in a Bose-Einstein condensate: A numerical study

DOE PAGES

Gertjerenken, B.; Kevrekidis, P. G.; Carretero-González, R.; ...

2016-02-01

Here, we numerically investigate an experimentally viable method for generating and manipulating on-demand several vortices in a highly oblate atomic Bose-Einstein condensate (BEC) in order to initialize complex vortex distributions for studies of vortex dynamics. The method utilizes moving laser beams to generate, capture, and transport vortices inside and outside the BEC. This methodology is examined in detail and shows a wide parameter range of applicability for the prototypical two-vortex case, as well as case examples of producing and manipulating several vortices for which there is no net circulation, corresponding to equal numbers of positive and negative circulation vortices, andmore » cases for which there is one net quantum of circulation. We also find that the presence of dissipation can help stabilize the pinning of the vortices on their respective laser beam pinning sites. Finally, we illustrate how to utilize laser beams as repositories that hold large numbers of vortices and how to deposit individual vortices in a sequential fashion in the repositories in order to construct superfluid flows about the repository beams with several quanta of circulation.« less

[Changes in prostatic circulation in response to laser therapy and magnetic therapy in patients with benign prostatic hyperplasia].

PubMed

2005-01-01

The results of preoperative preparation were analysed in 59 patients with prostatic benign hyperplasia (PBH) subjected to TUR. Treatment outcomes were assessed by transrectal ultrasound (color Doppler mapping) in two groups of patients. Group 1 received combined therapy including transrectal laser radiation of the prostate, group 2--transrectal magnetotherapy. The analysis showed that laser radiation reduced insignificantly the size of the prostate and adenomatous node, improved microcirculation and circulation in the prostate. This resulted in relief of inflammation and reduction of the number of postoperative inflammatory complications. Transrectal magnetotherapy has a positive effect on vascularization and hemodynamics of the prostate, local immunity, contamination of the tissues with pathogenic flora.

Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression

NASA Astrophysics Data System (ADS)

Varshnay, N. K.; Singh, A.; Benerji, N. S.

2017-02-01

Performance characteristics of an excimer laser (XeCl) with single-stage magnetic pulse compression suitable for material processing applications are presented here. The laser incorporates in-built compact gas circulation and gas cooling to ensure fresh gas mixture between the electrodes for repetitive operation. A magnetically coupled tangential blower is used for gas circulation inside the laser chamber for repetitive operation. The exciter consists of C-C energy transfer circuit and thyratron is used as a high-voltage main switch with single-stage magnetic pulse compression (MPC) between thyratron and the laser electrodes. Low inductance of the laser head and uniform and intense pre-ionization are the main features of the electric circuit used in the laser. A 250 ns rise time voltage pulse was compressed to 100 ns duration with a single-stage magnetic pulse compressor using Ni-Zn ferrite cores. The laser can generate about 150 mJ at ˜100 Hz rep-rate reliably from a discharge volume of 100 cm 3. 2D spatial laser beam profile generated is presented here. The profile shows that the laser beam is completely filled with flat-top which is suitable for material processing applications. The SEM image of the microhole generated on copper target is presented here.

Geoscience Laser Altimetry System (GLAS) Loop Heat Pipe Anomaly and On Orbit Testing

NASA Technical Reports Server (NTRS)

Baker, Charles; Butler, Dan; Grob, Eric; Jester, Peggy

2011-01-01

The Geoscience Laser Altimetry System (GLAS) is the sole instrument on the ICESat Satellite. On day 230 of 2003, the GLAS Component Loop Heat Pipe (CLHP) entered a slow circulation mode that resulted in the main electronics box reaching its hot safing temperature, after which the entire instrument was turned off. The CLHP had a propylene working fluid and was actively temperature controlled via a heater on the compensation chamber. The slow circulation mode happened right after a planned propulsive yaw maneuver with the spacecraft. It took several days to recover the CLHP and ensure that it was still operational. The recovery occurred after the entire instrument was cooled to survival temperatures and the CLHP compensation chamber cycled on a survival heater. There are several theories as to why this slow circulation mode exhibited itself, including: accumulation of Non-Condensible Gas (NCG), the secondary wick being under designed or improperly implemented, or an expanded (post-launch) leak across the primary wick. Each of these is discussed in turn, and the secondary wick performance is identified as the most likely source of the anomalous behavior. After the anomaly, the CLHP was controlled to colder temperatures to improve its performance (as the surface tension increases with lower temperature, as does the volume of liquid in the compensation chamber) and only precursor pulses occurred later in the mission. After GLAS s last laser failed, in late 2009, a decision was made to conduct engineering tests of both LHPs to try and duplicate this flight anomaly. The engineering tests consisted of control setpoint changes, sink changes, and one similar propulsive Yaw maneuver. The only test that showed any similar anomaly precursors on the CLHP was the propulsive maneuver followed by a setpoint increase. The ICESat Satellite was placed in a decaying orbit and ended its mission on August 30, 2010 in Barents Sea.

A 532 nm Chaotic Fiber Laser Transmitter for Underwater Lidar

DTIC Science & Technology

2013-04-23

passes through unaffected. 3.1.1.2 Ring Lasers as Oscillators The simplest form of laser is a called a Fabry - Perot laser, in which two reflectors are...insufficient to drive the gain amplifier, and so the circulator-based design was scrapped in favor of the Fabry - Perot , whose efficiency was far better...Bidirectional Ring and Fabry - Perot Lasers The Fabry - Perot laser used two matched FBGs to create a wavelength-selective resonator cavity. First single- and

An experimental study of a turbulent boundary layer in the trailing edge region of a circulation-control airfoil

NASA Technical Reports Server (NTRS)

Heinemann, K.; Brown, Jeff

1992-01-01

This report discusses progress made on NASA Cooperative Agreement NCC2-545, 'An Experimental Study of a Turbulent Boundary Layer in the Trailing-Edge Region of a Circulation-Control Airfoil' during the period 9/1/91 through 9/30/92. The study features 2-component laser Doppler velocimeter (LDV) measurements in the trailing edge and wake regions of a generic 2-dimensional circulation-control model. The final experimental phase of the study will be carried out in the Ames High Reynolds Number Channel 2 (HRC2) transonic blow-down-facility. During the 13-month period covered by this report, work continued on the development of the near-wall laser Doppler velocimeter (LDV) described in previous reports.

Useful method to monitor the physiological effects of alcohol ingestion by combination of micro-integrated laser Doppler blood flow meter and arm-raising test.

PubMed

Iwasaki, Wataru; Nogami, Hirofumi; Ito, Hiroki; Gotanda, Takeshi; Peng, Yao; Takeuchi, Satoshi; Furue, Masutaka; Higurashi, Eiji; Sawada, Renshi

2012-10-01

Alcohol has a variety of effects on the human body, affecting both the sympathetic and parasympathetic nervous system. We examined the peripheral blood flow of alcohol drinkers using a micro-integrated laser Doppler blood flow meter (micro-electromechanical system blood flow sensor). An increased heart rate and blood flow was recorded at the earlobe after alcohol ingestion, and we observed strong correlation between blood flow, heart rate, and breath alcohol content in light drinkers; but not heavy drinkers. We also found that the amplitude of pulse waves measured at the fingertip during an arm-raising test significantly decreased on alcohol consumption, regardless of the individual's alcohol tolerance. Our micro-electromechanical system blood flow sensor successfully detected various physiological changes in peripheral blood circulation induced by alcohol consumption.

In vivo cell tracking and quantification method in adult zebrafish

NASA Astrophysics Data System (ADS)

Zhang, Li; Alt, Clemens; Li, Pulin; White, Richard M.; Zon, Leonard I.; Wei, Xunbin; Lin, Charles P.

2012-03-01

Zebrafish have become a powerful vertebrate model organism for drug discovery, cancer and stem cell research. A recently developed transparent adult zebrafish using double pigmentation mutant, called casper, provide unparalleled imaging power in in vivo longitudinal analysis of biological processes at an anatomic resolution not readily achievable in murine or other systems. In this paper we introduce an optical method for simultaneous visualization and cell quantification, which combines the laser scanning confocal microscopy (LSCM) and the in vivo flow cytometry (IVFC). The system is designed specifically for non-invasive tracking of both stationary and circulating cells in adult zebrafish casper, under physiological conditions in the same fish over time. The confocal imaging part in this system serves the dual purposes of imaging fish tissue microstructure and a 3D navigation tool to locate a suitable vessel for circulating cell counting. The multi-color, multi-channel instrument allows the detection of multiple cell populations or different tissues or organs simultaneously. We demonstrate initial testing of this novel instrument by imaging vasculature and tracking circulating cells in CD41: GFP/Gata1: DsRed transgenic casper fish whose thrombocytes/erythrocytes express the green and red fluorescent proteins. Circulating fluorescent cell incidents were recorded and counted repeatedly over time and in different types of vessels. Great application opportunities in cancer and stem cell researches are discussed.

Characteristics research on self-amplified distributed feedback fiber laser

NASA Astrophysics Data System (ADS)

Song, Zhiqiang; Qi, Haifeng; Guo, Jian; Wang, Chang; Peng, Gangding

2014-09-01

A distributed feedback (DFB) fiber laser with a ratio of the backward to forward output power of 1:100 was composed by a 45-mm-length asymmetrical phase-shifted fiber grating fabricated on the 50-mm erbium-doped photosensitive fiber. Forward output laser was amplified using a certain length of Nufern EDFL-980-Hp erbium-doped fiber to absorb the surplus pump power after the active phase-shifted fiber grating and get population inversion. By using OptiSystem software, the best fiber length of the EDFL to get the highest gain was simulated. In order to keep the amplified laser with the narrow line-width and low noise, a narrow-band light filter consisting of a fiber Bragg grating (FBG) with the same Bragg wavelength as the laser and an optical circulator was used to filter the amplified spontaneous emission (ASE) noise of the out-cavity erbium-doped fiber. The designed laser structure sufficiently utilized the pump power, and a DFB fiber laser with the 32.5-mW output power, 11.5-kHz line width, and -87-dB/Hz relative intensity noise (RIN) at 300 mW of 980 nm pump power was brought out.

Design and Performance of a Miniature Lidar Wind Profiler (MLWP)

NASA Technical Reports Server (NTRS)

Cornwell, Donald M., Jr.; Miodek, Mariusz J.

1998-01-01

The directional velocity of the wind is one of the most critical components for understanding meteorological and other dynamic atmospheric processes. Altitude-resolved wind velocity measurements, also known as wind profiles or soundings, are especially necessary for providing data for meteorological forecasting and overall global circulation models (GCM's). Wind profiler data are also critical in identifying possible dangerous weather conditions for aviation. Furthermore, a system has yet to be developed for wind profiling from the surface of Mars which could also meet the stringent requirements on size, weight, and power of such a mission. Obviously, a novel wind profiling approach based on small and efficient technology is required to meet these needs. A lidar system based on small and highly efficient semiconductor lasers is now feasible due to recent developments in the laser and detector technologies. The recent development of high detection efficiency (50%), silicon-based photon-counting detectors when combined with high laser pulse repetition rates and long receiver integration times has allowed these transmitter energies to be reduced to the order of microjoules per pulse. Aerosol lidar systems using this technique have been demonstrated for both Q-switched, diode-pumped solid-state laser transmitters (lambda = 523 nm) and semiconductor diode lasers (lambda = 830 nm); however, a wind profiling lidar based on this technique has yet to be developed. We will present an investigation of a semiconductor-laser-based lidar system which uses the "edge-filter" direct detection technique to infer Doppler frequency shifts of signals backscattered from aerosols in the planetary boundary layer (PBL). Our investigation will incorporate a novel semiconductor laser design which mitigates the deleterious effects of frequency chirp in pulsed diode lasers, a problem which has limited their use in such systems in the past. Our miniature lidar could be used on a future Mars lander and perhaps find its own niche in terrestrial applications due to its potential low cost an small size.

Elucidation of Free Radical and Optogalvanic Spectroscopy Associated with Microgravity Combustion via Conventional and Novel Laser Platforms

NASA Technical Reports Server (NTRS)

Misra, Prabhakar; She, Yong-Bo; Zhu, Xin-Ming; King, Michael

1997-01-01

Combustion studies under both normal gravity and microgravity conditions depend a great deal on the availability and quality of the diagnostic systems used for such investigations. Microgravity phenomena are specially susceptible to even small perturbations and therefore non-intrusive diagnostic techniques are of paramount importance for successful understanding of reduced-gravity combustion phenomena. Several non-intrusive diagnostic techniques are available for probing and delineating normal as well as reduced gravity combustion processes, such as Rayleigh scattering, Raman scattering, Mie scattering, velocimetry, interferometric and Schlieren techniques, emission and laser-induced fluorescence (LIF) spectroscopy. Our approach is to use the LIF technique as a non-intrusive diagnostic tool for the study of combustion-associated free radicals and use the concomitant optogalvanic transitions to accomplish precise calibration of the laser wavelengths used for recording the excitation spectra of transient molecular species. In attempting to perform spectroscopic measurements on chemical intermediates, we have used conventional laser sources as well as new and novel platforms employing rare-earth doped solid-state lasers. Conventional (commercially available) sources of tunable UV laser radiation are extremely cumbersome and energy-consuming devices that are not very suitable for either in-space or in-flight (or microgravity drop tower) experiments. Traditional LIF sources of tunable UV laser radiation involve in addition to a pump laser (usually a Nd:YAG laser with an attached frequency-doubling stage), a tunable dye laser. In turn, the dye laser has to be provided with a dye circulation system and a subsequent stage for frequency-doubling of the dye laser radiation, together with a servo-tuning system (termed the 'Autotracker') to follow the wavelength changes and also an optical system (called the 'Frequency Separator') for separation of the emanating visible and UV beams. In contrast to this approach, we have devised an alternate arrangement for recording LIF excitation spectra of free radicals (following appropriate precursor fragmentation) that utilizes a tunable rare-earth doped solid state laser system with direct UV pumping. We have designed a compact and portable tunable UV laser system incorporating features necessary for both in-space and in-flight spectroscopy experiments. For the purpose of LIF excitation, we have developed an all-solid-state tunable UV laser that employs direct pumping of the solid-state UV-active medium employing UV harmonics from a Nd:YAG laser. An optical scheme with counterpropagating photolysis and excitation beams focused by suitable lenses into a reaction vacuum chamber was employed.

Laser speckle contrast imaging of cerebral autoregulation in rats at a macro- and microcirculation level

NASA Astrophysics Data System (ADS)

Semyachkina-Glushkovskaya, O. V.; Abdurashitov, A. S.; Sindeev, S. S.; Tuchin, V. V.

2016-06-01

Using the method of laser speckle imaging for the simultaneous study of macro- and microcirculation in cerebral vessels of healthy rats, we show that the mechanisms underlying cerebral autoregulation depend on the initial condition of the organism and the sex of individual animals. The pharmacological dose-dependent stimulation of the peripheral arterial pressure increase is not accompanied by the cerebral circulation responses of analogous intensity, but manifests itself as 'compensating' reactions, namely, the redistribution of the blood flow at the level of macro- (in females) and microcirculation (in females and males). The obtained results extend our understanding of the capabilities of laser speckle imaging technique in neurophysiological studies of reserve abilities of cerebral circulation autoregulation under the conditions of hypertensive status formation.

A 4 U Laser Heterodyne Radiometer for Methane (CH4) and Carbon Dioxide (CO2) Measurements from an Occultation-Viewing CubSat

NASA Technical Reports Server (NTRS)

Wilson, Emily L.; DiGregorio, A. J.; Riot, Vincent J.; Ammons, Mark S.; Bruner, WIlliam W.; Carter, Darrell; Mao, Jianping; Ramanathan, Anand; Strahan, Susan E.; Oman, Luke D.;

Photon generator

DOEpatents

Srinivasan-Rao, Triveni

2002-01-01

A photon generator includes an electron gun for emitting an electron beam, a laser for emitting a laser beam, and an interaction ring wherein the laser beam repetitively collides with the electron beam for emitting a high energy photon beam therefrom in the exemplary form of x-rays. The interaction ring is a closed loop, sized and configured for circulating the electron beam with a period substantially equal to the period of the laser beam pulses for effecting repetitive collisions.

Fiber photo-catheters for laser treatment of atrial fibrillation

PubMed Central

Peshko, Igor; Rubtsov, Vladimir; Vesselov, Leonid; Sigal, Gennady; Laks, Hillel

2009-01-01

A fiber photo-catheter has been developed for surgical treatment of atrial fibrillation with laser radiation. Atrial fibrillation (AF) is a heart rhythm abnormality that involves irregular and rapid heartbeats. Recent studies demonstrate the superiority of treating AF disease with optical radiation of the near infrared region. To produce long continuous transmural lesions, solid-state lasers and laser diodes, along with end-emitting fiber catheters, have been used experimentally. The absence of side-emitting flexible catheters with the ability to produce long continuous lesions limits the further development of this technology. In this research, a prototype of an optical catheter, consisting of a flexible 10-cm fiber diffuser has been used to make continuous photocoagulation lesions for effective maze procedure treatments. The system also includes: a flexible optical reflector; a series of openings for rapid self-attachment to the tissue; and an optional closed-loop irrigating chamber with circulating saline to cool the optical diffuser and irrigate the tissue. PMID:19587838

Reviews of a Diode-Pumped Alkali Laser (DPAL): a potential high powered light source

NASA Astrophysics Data System (ADS)

Cai, He; Wang, You; Han, Juhong; An, Guofei; Zhang, Wei; Xue, Liangping; Wang, Hongyuan; Zhou, Jie; Gao, Ming; Jiang, Zhigang

2015-03-01

Diode pumped alkali vapor lasers (DPALs) were first developed by in W. F. Krupke at the beginning of the 21th century. In the recent years, DPALs have been rapidly developed because of their high Stokes efficiency, good beam quality, compact size and near-infrared emission wavelengths. The Stokes efficiency of a DPAL can achieve a miraculous level as high as 95.3% for cesium (Cs), 98.1% for rubidium (Rb), and 99.6% for potassium (K), respectively. The thermal effect of a DPAL is theoretically smaller than that of a normal diode-pumped solid-state laser (DPSSL). Additionally, generated heat of a DPAL can be removed by circulating the gases inside a sealed system. Therefore, the thermal management would be relatively simple for realization of a high-powered DPAL. In the meantime, DPALs combine the advantages of both DPSSLs and normal gas lasers but evade the disadvantages of them. Generally, the collisionally broadened cross sections of both the D1 and the D2 lines for a DPAL are much larger than those for the most conventional solid-state, fiber and gas lasers. Thus, DPALs provide an outstanding potentiality for realization of high-powered laser systems. It has been shown that a DPAL is now becoming one of the most promising candidates for simultaneously achieving good beam quality and high output power. With a lot of marvelous merits, a DPAL becomes one of the most hopeful high-powered laser sources of next generation.

Modular package for cooling a laser diode array

DOEpatents

Mundinger, David C.; Benett, William J.; Beach, Raymond J.

1992-01-01

A laser diode array is disclosed that includes a plurality of planar packages and active cooling. The laser diode array may be operated in a long duty cycle, or in continuous operation. A laser diode bar and a microchannel heat sink are thermally coupled in a compact, thin planar package having the laser diode bar located proximate to one edge. In an array, a number of such thin planar packages are secured together in a stacked configuration, in close proximity so that the laser diodes are spaced closely. The cooling means includes a microchannel heat sink that is attached proximate to the laser bar so that it absorbs heat generated by laser operation. To provide the coolant to the microchannels, each thin planar package comprises a thin inlet manifold and a thin outlet manifold connected to an inlet corridor and an outlet corridor. The inlet corridor comprises a hole extending through each of the packages in the array, and the outlet corridor comprises a hole extending through each of the packages in the array. The inlet and outlet corridors are connected to a conventional coolant circulation system. The laser diode array with active cooling has application as an optical pump for high power solid state lasers. Further, it can be incorporated in equipment such as communications devices and active sensors, and in military and space applications, and it can be useful in applications having space constraints and energy limitations.

State-of-the-art satellite laser range modeling for geodetic and oceanographic applications

NASA Technical Reports Server (NTRS)

Klosko, Steve M.; Smith, David E.

1993-01-01

Significant improvements have been made in the modeling and accuracy of Satellite Laser Range (SLR) data since the launch of LAGEOS in 1976. Some of these include: improved models of the static geopotential, solid-Earth and ocean tides, more advanced atmospheric drag models, and the adoption of the J2000 reference system with improved nutation and precession. Site positioning using SLR systems currently yield approximately 2 cm static and 5 mm/y kinematic descriptions of the geocentric location of these sites. Incorporation of a large set of observations from advanced Satellite Laser Ranging (SLR) tracking systems have directly made major contributions to the gravitational fields and in advancing the state-of-the-art in precision orbit determination. SLR is the baseline tracking system for the altimeter bearing TOPEX/Poseidon and ERS-1 satellites and thus, will play an important role in providing the Conventional Terrestrial Reference Frame for instantaneously locating the geocentric position of the ocean surface over time, in providing an unchanging range standard for altimeter range calibration, and for improving the geoid models to separate gravitational from ocean circulation signals seen in the sea surface. Nevertheless, despite the unprecedented improvements in the accuracy of the models used to support orbit reduction of laser observations, there still remain systematic unmodeled effects which limit the full exploitation of modern SLR data.

Application of long-circulating liposomes to cancer photodynamic therapy.

PubMed

Oku, N; Saito, N; Namba, Y; Tsukada, H; Dolphin, D; Okada, S

1997-06-01

Photodynamic therapy (PDT) as a cancer treatment is notable for its quite low side effects in comparison with those of chemotherapy and radiotherapy. However, the accumulation of porphyrin derivatives used in PDT into tumor tissues is rather low. Since long-circulating liposomes are known to accumulate passively into tumor tissues, we liposomalized a porphyrin derivative, benzoporphyrin derivative monoacid ring A (BPD-MA), and used these liposomes to investigate the usefulness of PDT for tumor-bearing mice. BPD-MA was liposomalized into glucuronate-modified liposomes, which are known to be long-circulating. These liposomes were injected i.v. into Balb/c mice bearing Meth A sarcoma, and tumor regression and survival time were monitored after irradiation with laser light. Tumor regression and complete curing of tumor (80% cure rate by the treatment with 6 mg/kg BPD-MA) were observed when long circulating liposomalized BPD-MA was injected and laser-irradiated. In contrast, only a 20% cure rate was obtained when the animals were treated with BPD-MA solution or BPD-MA entrapped in conventional liposomes. These results suggest that a long-circulating liposomal formulation of photo-sensitive agents is useful for PDT.

Thermographic and clinical evaluation of 808-nm laser photobiomodulation effects after third molar extraction.

PubMed

Pedreira, Amanda A; Wanderley, Flavia G; Sa, Maira F; Viena, Camila S; Perez, Adriano; Hoshi, Ryuichi; Leite, Marcia P; Reis, Silvia R; Medrado, Alena P

2016-08-01

A randomized, blind, controlled clinical study was conducted with a convenience sample of 24 patients to evaluate the effectiveness of an aluminum gallium arsenide (AlGaAs) infrared laser 808 nm after third molar extraction by the use of infrared thermography technique. Patients were divided into four groups: erupted third molars were extracted from the patients in Group I and Group II, and impacted third molars were extracted from the patients in Group III and Group IV. Group I and Group III received mock laser therapy in which the device was powered off, and Group II and Group IV were exposed to laser light. Postoperative clinical parameters related to the third molar extraction were evaluated; these parameters included pain, trismus and edema. Circulatory patterns were also evaluated by infrared thermography that exhibited local temperature coefficient at different postoperative periods. A slight improvement was observed for swelling, pain and trismus in patients who received laser irradiation, although the differences were not statistically significant (P>0.05). Laser therapy had a significant influence on the local circulation in the area near the temporomandibular joint, as determined by infrared thermography (P<0.05). Laser therapy was able to change the local circulation, although it did not significantly influence swelling, pain or trismus during the postoperative period.

Views on treatment of endometriosis by using laser acupuncture and moxibustion

NASA Astrophysics Data System (ADS)

Ye, Hongzheng

1993-03-01

This article emphasizes the treatment of endometriosis by using laser acupuncture and moxibustion which belongs to Shi Zhen. The major pathophysiology is that the circulation of the Qi and blood is obstructed. The obstruction of Qi leads to a block of blood and poor circulation which causes pain. The treatment should be introduced mainly by adjusting Qi and blood. We used an He-Ne low level laser instrument. Its export function is >= 20 mw, wavelength 6328 angstroms with a single-red light. By using a double tube fiber bundle it strikes directly on Liv. 3, Ren. 6, SP. 8. Each of the three points needs to be struck for five to ten minutes once a day. One therapy phase requires seven applications continually. This treatment results in cleaning the liver, adjusting the oxygen, and disencumbering the piles and the pain. When it makes the circulation of Qi free, the blood is normally transported and the pain disappears. After one or two phases of therapy, clinical re-examination indicated the disappearance of scleromata in the uterus. Five patients treated and continually re-checked recovered. Finally, their menses turned normal and clinical symptoms vanished within six months.

Laboratory studies of low temperature rate coefficients: The atmospheric chemistry of the outer planets

NASA Technical Reports Server (NTRS)

Leone, Stephen R.

1995-01-01

The objectives of the research are to measure low temperature laboratory rate coefficients for key reactions relevant to the atmospheres of Titan and Saturn. These reactions are, for example, C2H + H2, CH4, C2H2, and other hydrocarbons which need to be measured at low temperatures, down to approximately 150 K. The results of this work are provided to NASA specialists who study modeling of the hydrocarbon chemistry of the outer planets. The apparatus for this work consists of a pulsed laser photolysis system and a tunable F-center probe laser to monitor the disappearance of C2H. A low temperature cell with a cryogenic circulating fluid in the outer jacket provides the gas handling system for this work. These elements have been described in detail in previous reports. Several new results are completed and the publications are just being prepared. The reaction of C2H with C2H2 has been measured with an improved apparatus down to 154 K. An Arrhenius plot indicates a clear increase in the rate coefficient at the lowest temperatures, most likely because of the long-lived (C4H3) intermediate. The capability to achieve the lowest temperatures in this work was made possible by construction of a new cell and addition of a multipass arrangement for the probe laser, as well as improvements to the laser system.

Plasma Membrane Integrity and Survival of Melanoma Cells After Nanosecond Laser Pulses

PubMed Central

Pérez-Gutiérrez, Francisco G.; Camacho-López, Santiago; Evans, Rodger; Guillén, Gabriel; Goldschmidt, Benjamin S.; Viator, John A.

2010-01-01

Circulating tumor cells (CTCs) photoacoustic detection systems can aid clinical decision-making in the treatment of cancer. Interaction of melanin within melanoma cells with nanosecond laser pulses generates photoacoustic waves that make its detection possible. This study aims at: (1) determining melanoma cell survival after laser pulses of 6 ns at λ = 355 and 532 nm; (2) comparing the potential enhancement in the photoacoustic signal using λ = 355 nm in contrast with λ = 532 nm; (3) determining the critical laser fluence at which melanin begins to leak out from melanoma cells; and (4) developing a time-resolved imaging (TRI) system to study the intracellular interactions and their effect on the plasma membrane integrity. Monolayers of melanoma cells were grown on tissue culture-treated clusters and irradiated with up to 1.0 J/cm2. Surviving cells were stained with trypan blue and counted using a hemacytometer. The phosphate buffered saline absorbance was measured with a nanodrop spectrophotometer to detect melanin leakage from the melanoma cells post-laser irradiation. Photoacoustic signal magnitude was studied at both wavelengths using piezoelectric sensors. TRI with 6 ns resolution was used to image plasma membrane damage. Cell survival decreased proportionally with increasing laser fluence for both wavelengths, although the decrease is more pronounced for 355 nm radiation than for 532 nm. It was found that melanin leaks from cells equally for both wavelengths. No significant difference in photoacoustic signal was found between wavelengths. TRI showed clear damage to plasma membrane due to laser-induced bubble formation. PMID:20589533

Thin planar package for cooling an array of edge-emitting laser diodes

DOEpatents

Mundinger, David C.; Benett, William J.

1992-01-01

A laser diode array is disclosed that includes a plurality of planar assemblies and active cooling of each assembly. The laser diode array may be operated in a long duty cycle, or in continuous operation. A laser diode bar and a microchannel heat sink are thermally coupled in a compact, thin planar assembly having the laser diode bar located proximate to one edge. In an array, a number of such thin planar assemblies are secured together in a stacked configuration, in close proximity so that the laser diodes are spaced closely. The cooling means includes a microchannel heat sink proximate to the laser diode bar to absorb heat generated by laser operation. To provide the coolant to the microchannels, each thin planar assembly comprises passageways that connect the microchannels to inlet and outlet corridors. Each inlet passageway may comprise a narrow slot that directs coolant into the microchannels and increases the velocity of flow therethrough. The corridors comprises holes extending through each of the assemblies in the array. The inlet and outlet corridors are connected to a conventional coolant circulation system. The laser diode array with active cooling has applications as an optical pump for high power solid state lasers, or by mating the diodes with fiber optic lenses. Further, the arrays can be useful in applications having space constraints and energy limitations, and in military and space applications. The arrays can be incorporated in equipment such as communications devices and active sensors.

A 4 U laser heterodyne radiometer for methane (CH4) and carbon dioxide (CO2) measurements from an occultation-viewing CubeSat

NASA Astrophysics Data System (ADS)

Wilson, Emily L.; DiGregorio, A. J.; Riot, Vincent J.; Ammons, Mark S.; Bruner, William W.; Carter, Darrell; Mao, Jianping; Ramanathan, Anand; Strahan, Susan E.; Oman, Luke D.; Hoffman, Christine; Garner, Richard M.

2017-03-01

We present a design for a 4 U (20 cm  ×  20 cm  ×  10 cm) occultation-viewing laser heterodyne radiometer (LHR) that measures methane (CH4), carbon dioxide (CO2) and water vapor (H2O) in the limb that is designed for deployment on a 6 U CubeSat. The LHR design collects sunlight that has undergone absorption by the trace gas and mixes it with a distributive feedback (DFB) laser centered at 1640 nm that scans across CO2, CH4, and H2O absorption features. Upper troposphere/lower stratosphere measurements of these gases provide key inputs to stratospheric circulation models: measuring stratospheric circulation and its variability is essential for projecting how climate change will affect stratospheric ozone.

Intrapulpal Temperature Increases Caused by 445-nm Diode Laser-Assisted Debonding of Self-Ligating Ceramic Brackets During Simulated Pulpal Fluid Circulation.

PubMed

Stein, Steffen; Wenzler, Johannes; Hellak, Andreas; Schauseil, Michael; Korbmacher-Steiner, Heike; Braun, Andreas

2018-04-01

This study investigated temperature increases in dental pulp resulting from laser-assisted debonding of ceramic brackets using a 445-nm diode laser. Eighteen ceramic brackets were bonded in standardized manner to 18 caries-free human third molars. Pulpal fluid circulation was simulated by pumping distilled water at 37°C through the pulp chamber. The brackets were irradiated with a 445-nm diode laser. Temperatures were measured using a thermal camera at points P1 (center of the pulp) and P2 (in the hard dental tissue) at the baseline (T0), at the start and end of laser application (T1 and T2), and the maximum during the sequence (T max ). Significant differences in the temperatures measured at P1 and P2 were observed among T0, T1, T2, and T max . Significant increases in temperature were noted at points P1 and P2, between T1 and T2, T1 and T max , and T2 and T max . The maximum P2 values were significantly higher than at P1. The maximum temperature increase measured in the pulp was 2.23°C, lower than the critical threshold of 5.5°C. On the basis of the laser settings used, there is no risk to the vitality of dental pulp during laser-assisted debonding of ceramic brackets with a 445-nm diode laser.

Apparatus and method for measurement of weak optical absorptions by thermally induced laser pulsing

DOEpatents

Cremers, D.A.; Keller, R.A.

1982-06-08

The thermal lensing phenomenon is used as the basis for measurement of weak optical absorptions when a cell containing the sample to be investigated is inserted into a normally continuous-wave operation laser-pumped dye laser cavity for which the output coupler is deliberately tilted relative to intracavity circulating laser light, and pulsed laser output ensues, the pulsewidth of which can be rlated to the sample absorptivity by a simple algorithm or calibration curve. A minimum detection limit of less than 10/sup -5/ cm/sup -1/ has been demonstrated using this technique.

Apparatus and method for measurement of weak optical absorptions by thermally induced laser pulsing

DOEpatents

Cremers, D.A.; Keller, R.A.

1985-10-01

The thermal lensing phenomenon is used as the basis for measurement of weak optical absorptions when a cell containing the sample to be investigated is inserted into a normally continuous-wave operation laser-pumped dye laser cavity for which the output coupler is deliberately tilted relative to intracavity circulating laser light, and pulsed laser output ensues, the pulsewidth of which can be related to the sample absorptivity by a simple algorithm or calibration curve. A minimum detection limit of less than 10[sup [minus]5] cm[sup [minus]1] has been demonstrated using this technique. 6 figs.

Apparatus and method for measurement of weak optical absorptions by thermally induced laser pulsing

DOEpatents

Cremers, David A.; Keller, Richard A.

1985-01-01

The thermal lensing phenomenon is used as the basis for measurement of weak optical absorptions when a cell containing the sample to be investigated is inserted into a normally continuous-wave operation laser-pumped dye laser cavity for which the output coupler is deliberately tilted relative to intracavity circulating laser light, and pulsed laser output ensues, the pulsewidth of which can be related to the sample absorptivity by a simple algorithm or calibration curve. A minimum detection limit of less than 10.sup.-5 cm.sup.-1 has been demonstrated using this technique.

Femtosecond laser pulse optimization for multiphoton cytometry and control of fluorescence

NASA Astrophysics Data System (ADS)

Tkaczyk, Eric Robert

This body of work encompasses optimization of near infrared femtosecond laser pulses both for enhancement of flow cytometry as well as adaptive pulse shaping to control fluorescence. A two-photon system for in vivo flow cytometry is demonstrated, which allows noninvasive quantification of circulating cell populations in a single live mouse. We monitor fluorescently-labeled red blood cells for more than two weeks, and are also able to noninvasively measure circulation times of two distinct populations of breast cancer cells simultaneously in a single mouse. We build a custom laser excitation source in the form of an extended cavity mode-locked oscillator, which enables superior detection in whole blood or saline of cell lines expressing fluorescent proteins including the green fluorescent protein (GFP), tdTomato and mPlum. A mathematical model explains unique features of the signals. The ability to distinguish different fluorescent species is central to simultaneous measurement of multiple molecular targets in high throughput applications including the multiphoton flow cytometer. We demonstrate that two dyes which are not distinguishable to one-photon measurements can be differentiated and in fact quantified in mixture via phase-shaped two-photon excitation pulses found by a genetic algorithm. We also selectively enhance or suppress two-photon fluorescence of numerous common dyes with tailored pulse shapes. Using a multiplicative (rather than ratiometric) fitness parameter, we are able to control the fluorescence while maintaining a strong signal. With this method, we control the two-photon fluorescence of the blue fluorescent protein (BFP), which is of particular interest in investigations of protein-protein interactions, and has frustrated previous attempts of control. Implementing an acousto-optic interferometer, we use the same experimental setup to measure two-photon excitation cross-sections of dyes and prove that photon-photon interferences are the predominant mechanism of control. This research establishes the basis for molecularly tailored pulse shaping in multiphoton flow cytometry, which will advance our ability to probe the biology of circulating cells during disease progression and response to therapy.

Evaluation of laser radiation regimes at thermal tissue destruction

NASA Astrophysics Data System (ADS)

Ivanov, Anatoly; Kazaryan, Mishik A.; Molodykh, E. I.; Shchetinkina, T. A.

1996-01-01

The existing methods of laser destruction of biotissues, widely spread in surgery and coagulation action, are based on local heat emission in the tissues after light absorption. Here we present the results of the simulation of tissues heat destruction, taking into account the influence of blood and lymph circulation on the processes of heat transfer. The problem is adapted to the case of liver tissue with tumor. A liver is considered as a capillary-porous body with internal blood circulation. Heatconductivity and tissue-blood heat transfer are considered. Heat action is assumed to be implemented with contact laser scalpel. The mathematical model consists of two inhomogeneous nonlinear equations of heatconductivity with spherical symmetry. Nonstationary temperature fields of tissue and blood are determined and the main parameters are: (1) coefficients of heatconductivity and capacitance of blood and tissue, (2) blood and tissue density, (3) total metabolic energy, (4) volume coefficient accounting for heat-exchange between tissue and blood, and (5) blood circulation velocity. The power of laser radiation was taken into account in boundary conditions set for the center of coagulated tissue volume. We also took into account the process connected with changing of substance phase (vaporization). The original computer programs allow one to solve the problem varying in a wide range of the main parameters. Reasonable agreement was found between the calculation results and the experimental data for operations on microsamples and on test animals. It was demonstrated, in particular, that liver tissue coagulation regime is achieved at 10 W laser power during 25 s. The coagulation radius of 0.7 cm with the given tumor radius of 0.5 cm corresponds to the real clinical situation in case of metastasis liver affection.

Apparatus for improving the working time of the XeBr laser

DOEpatents

Sander, R.K.; Balog, G.; Seegmiller, E.T.

1980-03-04

In XeBr lasers which make use of HBr as the source of bromine, it has been found that the working life of the laser is limited because of dissociation of the HBr in the lasing region to form H/sub 2/ and Br/sub 2/. Accordingly, apparatus is disclosed for substantially improving the working time of the XeBr laser wherein means are provided for recombining H/sub 2/ and Br/sub 2/ into HBr and for continuously circulating the gaseous working medium from the lasing region through the recombination region.

Near-Millimeter Wave Technology Base Study: Volume I. Propagation and Target/Background Characteristics

DTIC Science & Technology

1979-11-01

diameter test cell used for laser propagation measurements is Path length-84 m to 2.0 km available and has been designed for circulating aerosols or...36- and 110-GHz and found an attenuation ratio of comparison measurements along a 4-km path with rain rate measured near the receiver end. a *02 They...time. Tipping-bucket systems . gauges are reliable, but become increasingly in- accurate at high rates . Flow gauges which The direct field measurement

Definition and Preliminary Design of the Laser Atmospheric Wind Sounder (LAWS) Phase 1. Volume 1: Executive Summary

NASA Technical Reports Server (NTRS)

1990-01-01

The laser atmospheric wind sounder (LAWS) is a facility instrument of the Earth Observing System (EOS) and is the culmination of over 20 years of effort in the field of laser Doppler wind sensing. LAWS will by the first instrument to fly in space with the capability of providing global-scale tropospheric wind profiles at high spatial resolutions. Global-scale wind profiles are necessary for: (1) more accurate diagnostics of large-scale circulation and climate dynamics; (2) improved numerical weather prediction; (3) improved understanding of mesoscale systems; (4) improved understanding of global biogeochemical and hydrologic cycles. The objective of phase 1 of the LAWS study was to evaluate competing concepts and develop a baseline configuration for the LAWS instrument. The first phase of the study consisted of identifying realistic concepts for LAWS and analyzing them in sufficient detail to be able to choose the most promising one for the LAWS application. System configurations were then developed for the chosen concept. The concept and subsequent configuration were to be compatible with two prospective platforms: the Japanese polar orbiting platform (JPOP) and the Space Station Freedom (as an attached payload). After an objective and comprehensive concept selection process, a heterodyne detection Doppler lidar using a CO2 laser transmitter operating at 9.1 microns over a 2.1 micron system with a solid state laser was chosen. The CO2 lidar concept was then analyzed in detail to arrive at a configuration for the instrument and its major subsystems. A configuration for LAWS was arrived at which meets the performance requirements, and this design is presented.

A Tester for Carbon Nanotube Mode Lockers

NASA Astrophysics Data System (ADS)

Song, Yong-Won; Yamashita, Shinji

2007-05-01

We propose and demonstrate a tester for laser pulsating operation of carbon nanotubes employing a circulator with the extra degree of freedom of the second port to access diversified nanotube samples. The nanotubes are deposited onto the end facet of a dummy optical fiber by spray method that guarantees simple sample loading along with the minimized perturbation of optimized laser cavity condition. Resultant optical spectra, autocorrelation traces and pulse train of the laser outputs with qualified samples are presented.

Apparatus for improving the working time of the XeBr laser

DOEpatents

Sander, Robert K.; Balog, George; Seegmiller, Emma T.

1982-01-01

In XeBr lasers which make use of HBr as the source of bromine, it has been found that the working life of the laser is limited because of dissociation of the HBr in the lasing region to form H.sub.2 and Br.sub.2. Accordingly, apparatus is disclosed for substantially improving the working time of the XeBr laser wherein means are provided for recombining H.sub.2 and Br.sub.2 into HBr and for continuously circulating the gaseous working medium from the lasing region through the recombination region. BACKGROUND OF THE INVENTION

Laser pointers: toys, nuisances, or significant eye hazards?

PubMed

Yolton, R L; Citek, K; Schmeisser, E; Reichow, A W; Griffith, T

1999-05-01

Laser pointers have been used inappropriately to harass and "dazzle" victims. Reports of retinal damage caused by pointers have also been circulated in the popular press. Information on pointer abuse was collected from the literature and through discussions with specialists. Few, if any, documented cases of permanent retinal damage caused by laser pointers could be found. For actual damage to occur, viewing, times need to exceed approximately 10 seconds. Exposures of this duration would require the person being lased to cooperate by holding fixation on the laser beam. Although the risk of permanent retinal damage from a laser-pointer beam is minimal, other risks include dazzle, annoyance, and concern that a weapon-aiming device rather than a pointer is generating the laser beam.

Integrated Device for Circulating Tumor Cell Capture, Characterization, and Lens-Free Microscopy

DTIC Science & Technology

2012-08-01

prototype consists of an Excelsior-532-200- CDRH laser (wavelength = 532 nm) as the light source, a simple Thorlabs Fig. 2.  (a) Wide FOV image of a...demonstration, as shown in Fig. 1(a), used a laser (Excelsior-532-200- CDRH , Spectra Physics, with wavelength of 532 nm and power of 200 mW) as light

Mode calculations in unstable resonators with flowing saturable gain. 1:hermite-gaussian expansion.

PubMed

Siegman, A E; Sziklas, E A

1974-12-01

We present a procedure for calculating the three-dimensional mode pattern, the output beam characteristics, and the power output of an oscillating high-power laser taking into account a nonuniform, transversely flowing, saturable gain medium; index inhomogeneities inside the laser resonator; and arbitrary mirror distortion and misalignment. The laser is divided into a number of axial segments. The saturated gain-and-index variation. across each short segment is lumped into a complex gain profile across the midplane of that segment. The circulating optical wave within the resonator is propagated from midplane to midplane in free-space fashion and is multiplied by the lumped complex gain profile upon passing through each midplane. After each complete round trip of the optical wave inside the resonator, the saturated gain profiles are recalculated based upon the circulating fields in the cavity. The procedure when applied to typical unstable-resonator flowing-gain lasers shows convergence to a single distorted steady-state mode of oscillation. Typical near-field and far-field results are presented. Several empirical rules of thumb for finite truncated Hermite-Gaussian expansions, including an approximate sampling theorem, have been developed as part of the calculations.

Application of intravenous helium-neon (He-Ne) laser therapy to patients with respiratory insufficiency: introductory report

NASA Astrophysics Data System (ADS)

Pisula, K.; Gaszynski, W.; Piotrowski, D.

1996-03-01

In this paper the authors present an unconventional method of intravenous laser therapy applied to nine patients treated in ICU for acute respiratory insufficiency. The laser therapy treatment was applied twice in 24 hours by introducing a quartz light pipe into a peripheral vein of the forearm connected to the He-Ne laser produced by Amber, Poland. In order to irradiate the whole circulating blood the procedure lasted twenty minutes. The initial observation showed the improvement of the respiratory parameters and the decrease of leucocytosis. During the intravenous laser therapy the ARDS was not observed in the patients, despite the existence of risk factors.

LAWS (Laser Atmospheric Wind Sounder) earth observing system

NASA Technical Reports Server (NTRS)

1988-01-01

Wind profiles can be measured from space using current technology. These wind profiles are essential for answering many of the interdisciplinary scientific questions to be addressed by EOS, the Earth Observing System. This report provides guidance for the development of a spaceborne wind sounder, the Laser Atmospheric Wind Sounder (LAWS), discussing the current state of the technology and reviewing the scientific rationale for the instrument. Whether obtained globally from the EOS polar platform or in the tropics and subtropics from the Space Station, wind profiles from space will provide essential information for advancing the skill of numerical weather prediction, furthering knowledge of large-scale atmospheric circulation and climate dynamics, and improving understanding of the global biogeochemical and hydrologic cycles. The LAWS Instrument Panel recommends that it be given high priority for new instrument development because of the pressing scientific need and the availability of the necessary technology. LAWS is to measure wind profiles with an accuracy of a few meters per second and to sample at intervals of 100 km horizontally for layers km thick.

Real-time photoacoustic flow cytography and photothermolysis of single circulating melanoma cells in vivo

NASA Astrophysics Data System (ADS)

He, Yun; Wang, Lidai; Shi, Junhui; Yao, Junjie; Li, Lei; Zhang, Ruiying; Huang, Chih-Hsien; Zou, Jun; Wang, Lihong V.

2017-03-01

Metastasis is responsible for as many as 90% of cancer-related deaths, and the deadliest skin cancer, melanoma, has a high propensity for metastasis. Since hematogenous spread of circulating tumor cells (CTCs) is cancer's main route of metastasis, detecting and destroying CTCs can impede metastasis and improve patients' prognoses. Extensive studies employing exogenous agents to detect tumor-specific biomarkers and guide therapeutics to CTCs have achieved promising results, but biosafety remains a critical concern. Taking another approach, physical detection and destruction of CTCs is a safer way to evaluate and reduce metastasis risks. Melanoma cells strongly express melanosomes, providing a striking absorption contrast with the blood background in the red to near-infrared spectrum. Exploiting this intrinsic optical absorption contrast of circulating melanoma cells, we coupled dual-wavelength photoacoustic flow cytography with a nanosecond-pulsed laser killing mechanism that specifically targets melanoma CTCs. We have successfully achieved in vivo label-free imaging of rare single CTCs and CTC clusters in mice. Further, the photoacoustic signal from a CTC immediately hardware-triggers a lethal pinpoint laser irradiation that lyses it on the spot in a thermally confined manner. Our technology can facilitate early inhibition of metastasis by clearing circulating tumor cells from vasculature.

A selective laser sintering guide for transferring a virtual plan to real time surgery in composite mandibular reconstruction with free fibula osseous flaps.

PubMed

Leiggener, C; Messo, E; Thor, A; Zeilhofer, H-F; Hirsch, J-M

2009-02-01

The free fibular flap is the standard procedure for reconstructing mandibular defects. The graft has to be contoured to fit the defect so preoperative planning is required. The systems used previously do not allow transfer of the surgical plan to the operation room in an optimal way. The authors present a method to bring the virtual plan to real time surgery using a rapid prototyping guide. Planning was conducted using the Surgicase CMF software simulating surgery on a workstation. The osteotomies were translated into a rapid prototyping guide, sterilised and applied during surgery on the fibula allowing for the osteotomies and osteosynthesis to be performed with intact circulation. During reconstruction the authors were able to choose the best site for the osteotomies regarding circulation and as a result increased the precision and speed of treatment.

Micromachined Active Magnetic Regenerator for Low-Temperature Magnetic Coolers

NASA Technical Reports Server (NTRS)

Chen, Weibo; Jaeger, Michael D.

2013-01-01

A design of an Active Magnetic Regenerative Refrigeration (AMRR) system has been developed for space applications. It uses an innovative 3He cryogenic circulator to provide continuous remote/distributed cooling at temperatures in the range of 2 K with a heat sink at about 15 K. A critical component technology for this cooling system is a highly efficient active magnetic regenerator, which is a regenerative heat exchanger with its matrix material made of magnetic refrigerant gadolinium gallium garnet (GGG). Creare Inc. is developing a microchannel GGG regenerator with an anisotropic structured bed for high system thermal efficiency. The regenerator core consists of a stack of thin, single-crystal GGG disks alternating with thin polymer insulating layers. The insulating layers help minimize the axial conduction heat leak, since GGG has a very high thermal conductivity in the regenerator s operating temperature range. The GGG disks contain micro channels with width near 100 micrometers, which enhance the heat transfer between the circulating flow and the refrigerant bed. The unique flow configuration of the GGG plates ensures a uniform flow distribution across the plates. The main fabrication challenges for the regenerator are the machining of high-aspect-ratio microchannels in fragile, single-crystal GGG disks and fabrication and assembly of the GGG insulation layers. Feasibility demonstrations to date include use of an ultrashort- pulse laser to machine microchannels without producing unacceptable microcracking or deposition of recast material, as shown in the figure, and attachment of a thin insulation layer to a GGG disk without obstructing the flow paths. At the time of this reporting, efforts were focused on improving the laser machining process to increase machining speed and further reduce microcracking.

[The optimization of an early rehabilitation program for cerebral stroke patients: the use of different methods of magneto- and laser therapy].

PubMed

Kochetkov, A V; Gorbunov, F E; Minenkov, A A; Strel'tsova, E N; Filina, T F; Krupennikov, A I

2000-01-01

Magnetotherapy and laser therapy were used in complex and complex-combined regimens in 75 patients after cerebral ischemic or hemorrhagic stroke starting on the poststroke week 4-5. Clinico-neurologic, neurophysiological and cerebrohemodynamic findings evidence for the highest effectiveness of neurorehabilitation including complex magneto-laser therapy in hemispheric ischemic and hemorrhagic stroke of subcortical location in the absence of marked clinico-tomographic signs of dyscirculatory encephalopathy. Complex-combined magneto-laser therapy is more effective for correction of spastic dystonia. Mutual potentiation of magnetotherapy and laser therapy results in maximal development of collateral circulation and cerebral hemodynamic reserve (84% of the patients). Complex effects manifest in arteriodilating and venotonic effects. Complex magneto-laser therapy is accompanied by reduction of hyperthrombocythemia and hyperfibrinogenemia.

15 CFR 908.3 - Activities subject to reporting.

Code of Federal Regulations, 2010 CFR

2010-01-01

... sources to influence convective circulation or to evaporate fog; (3) Modifying the solar radiation... artificial wind generation; or (8) Using lasers or other sources of electromagnetic radiation. (b) In...

Particle size distribution of typical ceramic raw materials by laser granulometry

NASA Technical Reports Server (NTRS)

Wojnarovitsne, I. H.; Lenkel, M.

1984-01-01

The principles of the method are explained and the working of the CILAS 715 laser granulometer is described. The particle size distributions of milled glazes, quartz, feldspar and china clay were determined by this instrument and by Andreasen sedimentation. The agreement was good for isometric particles, but the china clay appears finer by sedimentation, because the platelets arrange themselves horizontally during sedimentation, while in the laser granulometer preferred orientation is prevented by circulation between the sample holder and the vibrated and stirred reservoir of the slip.

Ultra Narrowband Optical Filters for Water Vapor Differential Absorption Lidar (DIAL) Atmospheric Measurements

NASA Technical Reports Server (NTRS)

Stenholm, Ingrid; DeYoung, Russell J.

2001-01-01

Differential absorption lidar (DIAL) systems are being deployed to make vertical profile measurements of atmospheric water vapor from ground and airborne platforms. One goal of this work is to improve the technology of such DIAL systems that they could be deployed on space-based platforms. Since background radiation reduces system performance, it is important to reduce it. One way to reduce it is to narrow the bandwidth of the optical receiver system. However, since the DIAL technique uses two or more wavelengths, in this case separated by 0.1 nm, a fixed-wavelength narrowband filter that would encompass both wavelengths would be broader than required for each line, approximately 0.02 nm. The approach employed in this project is to use a pair of tunable narrowband reflective fiber Bragg gratings. The Bragg gratings are germanium-doped silica core fiber that is exposed to ultraviolet radiation to produce index-of-refraction changes along the length of the fiber. The gratings can be tuned by stretching. The backscattered laser radiation is transmitted through an optical circulator to the gratings, reflected back to the optical circulator by one of the gratings, and then sent to a photodiode. The filter reflectivities were >90 percent, and the overall system efficiency was 30 percent.

Curriculum guidelines and standards for dental laser education

NASA Astrophysics Data System (ADS)

White, Joel M.; et al.

1993-07-01

The curriculum guidelines for dental laser education were developed through a consensus process with members from dental academia, industry and private practice. This document was developed at a workshop on the development of standards for dental laser education and laser instructor certification held at the University of California, San Francisco on July 25 and 26, 1992. A working draft is currently being circulated among dental laser educators, researchers, practitioners, organized dentistry and members of industry. After further discussion, modification and review, the final document will be widely distributed and updated annually. Any questions concerning the guidelines may be addressed to the authors of this document in care of the organizer. Suggestions for the improvement of this standard and endorsement of this document are invited.

Fiber laser with combined feedback of core and cladding modes assisted by an intracavity long-period grating.

PubMed

Sáez-Rodriguez, D; Cruz, J L; Díez, A; Andrés, M V

2011-05-15

We present a fiber laser made in a single piece of conventional doped-core fiber that operates by combined feedback of the fundamental core mode LP((0,1)) and the high-order cladding mode LP((0,10)). The laser is an all-fiber structure that uses two fiber Bragg gratings and a long-period grating to select the modes circulating in the cavity; the laser emits at the coupling wavelength between the core mode LP((0,1)) and the counterpropagating cladding mode LP((0,10)) in the Bragg gratings. This work demonstrates the feasibility of high-order mode fiber lasers assisted by long-period gratings. © 2011 Optical Society of America

Definition and preliminary design of the Laser Atmospheric Wind Sounder (LAWS) phase 1. Volume 2

NASA Technical Reports Server (NTRS)

1990-01-01

The steps and engineering trades and analyses used in establishing the initial requirements and in developing a concept and configuration for the laser atmospheric wind sounder (LAWS) instrument. A summary of the performance anticipated from the baseline configuration, and a bibliography are presented. LAWS, which is a facility instrument of the Earth observing system (EOS), is the culmination of over 20 years of effort in the field of laser Doppler wind sensing and will be the first instrument to fly in space capable of providing global-scale tropospheric wind profiles at high spatial resolutions. Global-scale wind profiles are necessary for: (1) more accurate diagnosis of large-scale circulation and climate dynamics; (2) improved numerical weather prediction; (3) improved understanding of mesoscale systems; and (4) improved understanding of global biogeochemical and hydrologic cycles. The objective of phase 1 was to define and perform a preliminary design for the LAWS instrument. The definition phase consisted of identifying realistic concepts for LAWS and analyzing them in sufficient detail to be able to choose the most promising one for the LAWS instrument. Systems and subsystems configurations were then developed for the chosen concept. The concept and subsequent configuration were to be compatible with two prospective platforms: the Japanese polar orbiting platform (JPOP) and as an attached payload on the Space Station Freedom. After a thorough and objective concept selection process, a heterodyne detection Doppler lidar using a CO2 laser transmitter operating a 9.1 micron over a 2.1 micron solid state system was chosen. A configuration for LAWS that meets the performance requirements was designed at the conclusion of phase 1.

Laser anemometry measurements of natural circulation flow in a scale model PWR reactor system. [Pressurized Water Reactor

NASA Technical Reports Server (NTRS)

Kadambi, J. R.; Schneider, S. J.; Stewart, W. A.

1986-01-01

The natural circulation of a single phase fluid in a scale model of a pressurized water reactor system during a postulated grade core accident is analyzed. The fluids utilized were water and SF6. The design of the reactor model and the similitude requirements are described. Four LDA tests were conducted: water with 28 kW of heat in the simulated core, with and without the participation of simulated steam generators; water with 28 kW of heat in the simulated core, with the participation of simulated steam generators and with cold upflow of 12 lbm/min from the lower plenum; and SF6 with 0.9 kW of heat in the simulated core and without the participation of the simulated steam generators. For the water tests, the velocity of the water in the center of the core increases with vertical height and continues to increase in the upper plenum. For SF6, it is observed that the velocities are an order of magnitude higher than those of water; however, the velocity patterns are similar.

Effect of flow velocity on the photoacoustic detection for glucose aqueous solutions

NASA Astrophysics Data System (ADS)

Ren, Zhong; Liu, Guodong; Ding, Yu; Yao, Qingkai

2018-01-01

The blood glucose non-invasive detection has become the research hot-spot. The photoacoustic spectroscopy is a well-promising, high-efficient and noninvasive detection method because it combines the advantages of the pure optic and pure ultrasonic. In practice, the photoacoustic detection of blood glucose is impacted by many factors because the human body is a complicated bio-system. To study the effect of flow velocity in the blood vessel on the photoacoustic detection of blood glucose, a photoacoustic detection system based on optical parameter oscillator (OPO) pulsed laser induced ultrasonic was established. In this system, a 532nm pumped Nd: YAG OPO pulsed laser was used as the excitation source, and the photoacoustic signals of glucose were captured by ultrasonic transducer. Moreover, a set of blood circulation system was built to simulate the real blood flow situation in the human body. The experiments of the photoacoustic detection of glucose aqueous solutions with different concentrations at different flow velocities were experimentally investigated. Experimental results show that the photoacoustic peak-to-peak value linearly increases with the glucose concentration, but it decreases with the increase of the flow velocity although the profiles of photoacoustic signals don't change.

Self-organizing phenomena induced by LLLT in Henoch-Schoenlein purpura

NASA Astrophysics Data System (ADS)

Ailioaie, Laura; Ailioaie, C.

2001-06-01

Henoch-Schoenlein purpura is characterized by vasculitis of small vessels, particularly those of the skin, gastrointestinal tract, and kidney. Patients have characteristic purpuric skin rash plus all or some of the following: migratory polyarthralgias or polyarthritis, colicky abdominal pain, nephritis. Because until now there is no satisfactory treatment, we applied low level laser therapy (LLLT) in order to compare it with the classical therapy. Twenty-three children (2-15 years of age) have been treated at debut of the disease. They were randomly divided: group A (11 children) received LLLT; group B (12 children) was administrated classical therapy. Two GaAlAs diode lasers (670 nm and 830 nm) were used. The density of energy (4-8 J/cm2), irradiating frequency (2.4 Hz) was applied one session daily, using scanning technique under a special treatment protocol on cutaneous purpuric areas (20 sessions). The best results were obtained in laser group. Despite the complex medication, some patients from group B fell back into the former state after apparent improvement, and two children developed nephritis. The results could be explained by self-organization. LLLT is acting as a trigger factor causing certain systemic effects through circulating blood and a response of the entire immune system, by way of synergetic mechanisms.

Scientific analysis of satellite ranging data

NASA Technical Reports Server (NTRS)

Smith, David E.

1994-01-01

A network of satellite laser ranging (SLR) tracking systems with continuously improving accuracies is challenging the modelling capabilities of analysts worldwide. Various data analysis techniques have yielded many advances in the development of orbit, instrument and Earth models. The direct measurement of the distance to the satellite provided by the laser ranges has given us a simple metric which links the results obtained by diverse approaches. Different groups have used SLR data, often in combination with observations from other space geodetic techniques, to improve models of the static geopotential, the solid Earth, ocean tides, and atmospheric drag models for low Earth satellites. Radiation pressure models and other non-conservative forces for satellite orbits above the atmosphere have been developed to exploit the full accuracy of the latest SLR instruments. SLR is the baseline tracking system for the altimeter missions TOPEX/Poseidon, and ERS-1 and will play an important role in providing the reference frame for locating the geocentric position of the ocean surface, in providing an unchanging range standard for altimeter calibration, and for improving the geoid models to separate gravitational from ocean circulation signals seen in the sea surface. However, even with the many improvements in the models used to support the orbital analysis of laser observations, there remain systematic effects which limit the full exploitation of SLR accuracy today.

Dual-wavelength, mode-locked erbium-doped fiber laser employing a graphene/polymethyl-methacrylate saturable absorber.

PubMed

Lau, K Y; Abu Bakar, M H; Muhammad, F D; Latif, A A; Omar, M F; Yusoff, Z; Mahdi, M A

2018-05-14

Mode-locked fiber laser incorporating a saturable absorber is an attractive configuration due to its stability and simple structure. In this work, we demonstrate a dual-wavelength passively mode-locked erbium-doped fiber laser employing a graphene/polymethyl-methacrylate saturable absorber. A laser resonator is developed based on dual cavity architecture with unidirectional signal oscillation, which is connected by a fiber branch sharing a common gain medium and saturable absorber. Dual wavelength mode-locked fiber lasers are observed at approximately 1530 and 1560 nm with 22.6 mW pump power threshold. Soliton pulse circulates in the laser cavity with pulse duration of 900 and 940 fs at shorter and longer wavelengths, respectively. This work presents a viable option in developing a low threshold mode-locked laser source with closely spaced dual wavelength femtosecond pulses in the C-band wavelength region.

Control of a laser inertial confinement fusion-fission power plant

DOEpatents

Moses, Edward I.; Latkowski, Jeffery F.; Kramer, Kevin J.

2015-10-27

A laser inertial-confinement fusion-fission energy power plant is described. The fusion-fission hybrid system uses inertial confinement fusion to produce neutrons from a fusion reaction of deuterium and tritium. The fusion neutrons drive a sub-critical blanket of fissile or fertile fuel. A coolant circulated through the fuel extracts heat from the fuel that is used to generate electricity. The inertial confinement fusion reaction can be implemented using central hot spot or fast ignition fusion, and direct or indirect drive. The fusion neutrons result in ultra-deep burn-up of the fuel in the fission blanket, thus enabling the burning of nuclear waste. Fuels include depleted uranium, natural uranium, enriched uranium, spent nuclear fuel, thorium, and weapons grade plutonium. LIFE engines can meet worldwide electricity needs in a safe and sustainable manner, while drastically shrinking the highly undesirable stockpiles of depleted uranium, spent nuclear fuel and excess weapons materials.

Feasibility and clinical utility of ultra-widefield indocyanine green angiography.

PubMed

Klufas, Michael A; Yannuzzi, Nicolas A; Pang, Claudine E; Srinivas, Sowmya; Sadda, Srinivas R; Freund, K Bailey; Kiss, Szilárd

2015-03-01

To evaluate the feasibility and clinical utility of a novel noncontact scanning laser ophthalmoscope-based ultra-widefield indocyanine green angiographic system. Ultra-widefield indocyanine green angiographic images were captured using a modified Optos P200Tx that produced high-resolution images of the choroidal vasculature with up to a 200° field. Ultra-widefield indocyanine green angiography was performed on patients with a variety of retinal conditions to assess utility of this imaging technique for diagnostic purposes and disease treatment monitoring. Ultra-widefield indocyanine green angiography was performed on 138 eyes of 69 patients. Mean age was 58 ± 16.9 years (range, 24-85 years). The most common ocular pathologies imaged included central serous chorioretinopathy (24 eyes), uveitis (various subtypes, 16 eyes), age-related macular degeneration (12 eyes), and polypoidal choroidal vasculopathy (4 eyes). In all eyes evaluated with ultra-widefield indocyanine green angiography, high-resolution images of choroidal and retinal circulation were obtained with sufficient detail out to 200° of the fundus. In this series of 138 eyes, scanning laser ophthalmoscope-based ultra-widefield indocyanine green angiography was clinically practical and provided detailed images of both the central and peripheral choroidal circulation. Future studies are needed to refine the clinical value of this imaging modality and the significance of peripheral choroidal vascular changes in the diagnosis, monitoring, and treatment of ocular diseases.

Clinical efficiency of applying low-intensity laser therapy in treating dyscirculatory encephalopathy

NASA Astrophysics Data System (ADS)

Putilina, M. V.; Kozlov, V. I.; Vakhtin, V. I.

2001-04-01

An investigation was made of applying laser therapy combined with drug preparations in treating 300 patients affected by dyscirculatory encephalopathy. Neurological and neuropsychological examinations together with electroencephalography, rheoencephalography, computerized tomography, and magnetic resonance imaging were used to assess the patients' states prior to and after the treatment. It was found that the combined application of laser therapy and drug preparations produced a more pronounced therapeutic effect as compared with that produced by the separate application of laser therapy and drug preparations. The results obtained allowed us to conclude that the 0.89 micrometers laser infrared radiation increased patients' susceptibility to drugs. Moreover, the combined laser therapy improved the cerebral bloodflow and activated the metabolic and plastic functions of neurons. This decreased or eliminated late complications provoked by the cerebral blood circulation insufficiency.

Behavior of platelets stained by 5,6-CF-encapsulated PEGylated liposomes after laser irradiation of vessel wall: an in-vivo model for studying site-selective delivery of diagnostic or therapeutic agents

NASA Astrophysics Data System (ADS)

Mordon, Serge R.; Begu, Sylvie; Buys, Bruno; Tourne-Peteilh, Corine; Devoisselle, Jean-Marie

2001-05-01

Vascular endothelium serves as an extensive interface between circulating blood and various tissues and organs of the body. As such, it offers an accessible target for blood-borne pharmacological and genetic manipulations that can mediate both local and systemic effects. Thus, targeting of liposomes to activated vascular endothelial cells may provide a strategy for site-selective delivery in the vascular system with broad therapeutic applicability. This study aimed to evaluate an intravital fluorescence imaging technique to visualize in-situ and in real-time the activation of platelets after staining by 5,6-CF- encapsulated PEGylated liposomes injected intravenously. The study was performed on skin by using a dorsal skin-fold chamber implanted in golden hamsters using intravital microscopy. The skin micro circulation was observed with an intravital microscope (using x25 and x40 magnification) fitted with a Xenon light source and an epi-fluorescence assembly. An ultra-high sensitivity video-camera mounted on the microscope projected the image onto a monitor, and the images were recorded for play-back analysis with a digital video cassette recorder. An inflammatory response was induced by an Argon laser emitting at 514.5nm. The 80micrometers laser beam was focused on a vessel and its position was controlled with the microscope imaging system, it was possible to see individual platelets flowing in blood vessels. As liposomes were labeled with a fluorescent probe which was hydrophilic (located in the aqueous phase), the fluorescence of platelets was due only to the uptake of liposomes. After laser irradiation, platelets activation at sites of vascular injury was obtained. Tethering, translocation of some platelets inside the irradiated zone were clearly seen. At last, detachment and extravasation of platelets were observed. A perivascular fluorescence confirmed that platelets migrated across the basal lamina into the dermal connective tissue. In conclusion, staining of platelets using 5,6-CF-encapsulated PEGylated liposomes injected intravenously presents the following advantages: i) in-situ labeling, ii) use of hydrophilic marker located in an aqueous compartment within the platelet, iii) as the release of the fluorescence marker is slow due to the formulation of liposomes, labeling of platelets could be observed during the whole experiment. Laser irradiation of blood vessels in vivo can induce the different phases of platelet activation: i) recruitment, ii) adhesion, iii) detachment, iv) transmigration. The combination of these techniques (platelet staining with PEGylated liposomes, intravital fluorescence microscopy, laser irradiation) provides a powerful tool to study local inflammation, platelet activation and behavior of liposomes in situ and in real time at an inflammation site. These observations could be considered as a preliminary approach to study the targeting of drugs to an endothelium under inflammation environment.

Outline of Toshiba Business Information Center

NASA Astrophysics Data System (ADS)

Nagata, Yoshihiro

Toshiba Business Information Center gathers and stores inhouse and external business information used in common within the Toshiba Corp., and provides companywide circulation, reference and other services. The Center established centralized information management system by employing decentralized computers, electronic file apparatus (30cm laser disc) and other office automation equipments. Online retrieval through LAN is available to search the stored documents and increasing copying requests are processed by electronic file. This paper describes the purpose of establishment of the Center, the facilities, management scheme, systematization of the files and the present situation and plan of each information service.

Experimental and numerical studies on three dimensional GTA weld pool convection: Non-axisymmetric effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joshi, Y.; Dutta, P.; Schupp, P.E.

1995-12-31

Observations of surface flow patterns of steel and aluminum GTAW pools have been made using a pulsed laser visualization system. The weld pool convection is found to be three dimensional, with the azimuthal circulation depending on the location of the clamp with respect to the torch. Oscillation of steel pools and undulating motion in aluminum weld pools are also observed even with steady process parameters. Current axisymmetric numerical models are unable to explain such phenomena. A three dimensional computational study is carried out in this study to explain the rotational flow in aluminum weld pools.

Experimental research of adaptive OFDM and OCT precoding with a high SE for VLLC system

NASA Astrophysics Data System (ADS)

Liu, Shuang-ao; He, Jing; Chen, Qinghui; Deng, Rui; Zhou, Zhihua; Chen, Shenghai; Chen, Lin

2017-09-01

In this paper, an adaptive orthogonal frequency division multiplexing (OFDM) modulation scheme with 128/64/32/16-quadrature amplitude modulation (QAM) and orthogonal circulant matrix transform (OCT) precoding is proposed and experimentally demonstrated for a visible laser light communication (VLLC) system with a cost-effective 450-nm blue-light laser diode (LD). The performance of OCT precoding is compared with conventional the adaptive Discrete Fourier Transform-spread (DFT-spread) OFDM scheme, 32 QAM OCT precoding OFDM scheme, 64 QAM OCT precoding OFDM scheme and adaptive OCT precoding OFDM scheme. The experimental results show that OCT precoding can achieve a relatively flat signal-to-noise ratio (SNR) curve, and it can provide performance improvement in bit error rate (BER). Furthermore, the BER of the proposed OFDM signal with a raw bit rate 5.04 Gb/s after 5-m free space transmission is less than 20% of soft-decision forward error correlation (SD-FEC) threshold of 2.4 × 10-2, and the spectral efficiency (SE) of 4.2 bit/s/Hz can be successfully achieved.

The photonic device for integrated evaluation of collateral circulation of lower extremities in patients with local hypertensive-ischemic pain syndrome

NASA Astrophysics Data System (ADS)

Pavlov, Volodymyr S.; Bezsmernyi, Yurii O.; Zlepko, Sergey M.; Bezsmertna, Halyna V.

2017-08-01

The given paper analyzes principles of interaction and analysis of the reflected optical radiation from biotissue in the process of assessment of regional hemodynamics state in patients with local hypertensive- ischemic pain syndrome of amputation stumps of lower extremities, applying the method of photoplethysmography. The purpose is the evaluation of Laser photoplethysmography (LPPG) diagnostic value in examination of patients with chronic ischemia of lower extremities. Photonic device is developed to determine the level of the peripheral blood circulation, which determines the basic parameters of peripheral blood circulation and saturation level. Device consists of two sensors: infrared sensor, which contains the infrared laser radiation source and photodetector, and red sensor, which contains the red radiation source and photodetector. LPPG method allows to determined pulsatility of blood flow in different areas of the foot and lower leg, the degree of compensation and conservation perspectives limb. Surgical treatment of local hypertensive -ischemic pain syndrome of amputation stumps of lower extremities by means of semiclosed fasciotomy in combination with revasculating osteotrepanation enabled to improve considerably regional hemodynamics in the tissues of the stump and decrease pain and hypostatic disorders.

Symmetry, stability, and computation of degenerate lasing modes

NASA Astrophysics Data System (ADS)

Liu, David; Zhen, Bo; Ge, Li; Hernandez, Felipe; Pick, Adi; Burkhardt, Stephan; Liertzer, Matthias; Rotter, Stefan; Johnson, Steven G.

2017-02-01

We present a general method to obtain the stable lasing solutions for the steady-state ab initio lasing theory (SALT) for the case of a degenerate symmetric laser in two dimensions (2D). We find that under most regimes (with one pathological exception), the stable solutions are clockwise and counterclockwise circulating modes, generalizing previously known results of ring lasers to all 2D rotational symmetry groups. Our method uses a combination of semianalytical solutions close to lasing threshold and numerical solvers to track the lasing modes far above threshold. Near threshold, we find closed-form expressions for both circulating modes and other types of lasing solutions as well as for their linearized Maxwell-Bloch eigenvalues, providing a simple way to determine their stability without having to do a full nonlinear numerical calculation. Above threshold, we show that a key feature of the circulating mode is its "chiral" intensity pattern, which arises from spontaneous symmetry breaking of mirror symmetry, and whose symmetry group requires that the degeneracy persists even when nonlinear effects become important. Finally, we introduce a numerical technique to solve the degenerate SALT equations far above threshold even when spatial discretization artificially breaks the degeneracy.

Development and analysis of closed cycle circulator elements. Final report 31 Jul 978-31 May 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shih, C.C.; Karr, G.R.; Perkins, J.F.

1980-05-01

A series of experiments with various flow rates of laser gas and coolants under several levels of energy inputs has been conducted on the Army Closed Cycle Circulator for pulsed EDL to collect sufficient data for flow calibration and coefficient determination. Verification of the theoretical models depicting the functions of the heat exchangers in maintaining the thermal balance in the flow through the steady and transient states are made through comparison with results of the experimental analysis.

Laser apparatus

DOEpatents

Lewis, Owen; Stogran, Edmund M.

1980-01-01

Laser apparatus is described wherein an active laser element, such as the disc of a face-pumped laser, is mounted in a housing such that the weight of the element is supported by glass spheres which fill a chamber defined in the housing between the walls of the housing and the edges of the laser element. The uniform support provided by the spheres enable the chamber and the pump side of the laser element to be sealed without affecting the alignment or other optical properties of the laser element. Cooling fluid may be circulated through the sealed region by way of the interstices between the spheres. The spheres, and if desired also the cooling fluid may contain material which absorbs radiation at the wavelength of parasitic emissions from the laser element. These parasitic emissions enter the spheres through the interface along the edge surface of the laser element and it is desirable that the index of refraction of the spheres and cooling fluid be near the index of refraction of the laser element. Thus support, cooling, and parasitic suppression functions are all accomplished through the use of the arrangement.

Sensitivity of a three-mirror cavity to thermal and nonlinear lensing: Gaussian-beam analysis.

PubMed

Anctil, G; McCarthy, N; Piché, M

2000-12-20

We consider a compact three-mirror cavity consisting of a flat output coupler, a curved folding mirror, and an active medium with one facet cut at the Brewster angle and the other facet coated for unit reflectivity. We examine the sensitivity to thermal lensing and to self-focusing in the active medium of the Gaussian beam that is circulating in that cavity. We use a simple thin-lens model; the astigmatism of the beam that is circulating in the cavity and the nonlinear coupling between the field distributions along the two orthogonal axes are taken into account. We find configurations in which beam ellipticity is compensated for at either end of the cavity in the presence of thermal lensing. We have derived an analytical criterion that predicts the sensitivity of the beam size to nonlinear lensing. The ability of the cavity to favor self-mode locking is found to be sensitive to the strength of thermal lensing. In the absence of thermal lensing, cavities operated as telescopic systems (C = 0) or self-imaging systems (B = 0) are most appropriate for achieving self-mode locking, with nonlinear mode selection accomplished through saturation of the spatially varying laser gain. We identify conditions for which self-mode locking can be produced by variable-reflectivity output couplers with either maximum or minimum reflectivity at the center of the coupler. We use our model to estimate the nonlinear gain produced in laser cavities equipped with such output couplers. We identify a cavity configuration for which nonlinear lensing can simultaneously produce mode locking and correction of beam ellipticity at the output coupler.

Sensitivity of a Three-Mirror Cavity to Thermal and Nonlinear Lensing: Gaussian-Beam Analysis

NASA Astrophysics Data System (ADS)

Anctil, Geneviève; McCarthy, Nathalie; Piché, Michel

2000-12-01

We consider a compact three-mirror cavity consisting of a flat output coupler, a curved folding mirror, and an active medium with one facet cut at the Brewster angle and the other facet coated for unit reflectivity. We examine the sensitivity to thermal lensing and to self-focusing in the active medium of the Gaussian beam that is circulating in that cavity. We use a simple thin-lens model; the astigmatism of the beam that is circulating in the cavity and the nonlinear coupling between the field distributions along the two orthogonal axes are taken into account. We find configurations in which beam ellipticity is compensated for at either end of the cavity in the presence of thermal lensing. We have derived an analytical criterion that predicts the sensitivity of the beam size to nonlinear lensing. The ability of the cavity to favor self-mode locking is found to be sensitive to the strength of thermal lensing. In the absence of thermal lensing, cavities operated as telescopic systems ( C 0 ) or self-imaging systems ( B 0 ) are most appropriate for achieving self-mode locking, with nonlinear mode selection accomplished through saturation of the spatially varying laser gain. We identify conditions for which self-mode locking can be produced by variable-reflectivity output couplers with either maximum or minimum reflectivity at the center of the coupler. We use our model to estimate the nonlinear gain produced in laser cavities equipped with such output couplers. We identify a cavity configuration for which nonlinear lensing can simultaneously produce mode locking and correction of beam ellipticity at the output coupler.

Microgravity

NASA Image and Video Library

2001-01-24

An artist's concept of the Primary Atomic Clock Reference System (PARCS) plarned to fly on the International Space Station (ISS). PARCS will make even more accurate atomic time available to everyone, from physicists testing Einstein's Theory of Relativity, to hikers using the Global Positioning System to find their way. In ground-based atomic clocks, lasers are used to cool and nearly stop atoms of cesium whose vibrations are used as the time base. The microgravity of space will allow the atoms to be suspended in the clock rather than circulated in an atomic fountain, as required on Earth. PARCS is being developed by the Jet Propulsion Laboratory with principal investigators at the National Institutes of Standards and Technology and the University of Colorado, Boulder. See also No. 0103191

Vortex Rings Generated by a Shrouded Hartmann-Sprenger Tube

NASA Technical Reports Server (NTRS)

DeLoof, Richard L. (Technical Monitor); Wilson, Jack

2005-01-01

The pulsed flow emitted from a shrouded Hartmann-Sprenger tube was sampled with high-frequency pressure transducers and with laser particle imaging velocimetry, and found to consist of a train of vortices. Thrust and mass flow were also monitored using a thrust plate and orifice, respectively. The tube and shroud lengths were altered to give four different operating frequencies. From the data, the radius, velocity, and circulation of the vortex rings was obtained. Each frequency corresponded to a different length to diameter ratio of the pulse of air leaving the driver shroud. Two of the frequencies had length to diameter ratios below the formation number, and two above. The formation number is the value of length to diameter ratio below which the pulse converts to a vortex ring only, and above which the pulse becomes a vortex ring plus a trailing jet. A modified version of the slug model of vortex ring formation was used to compare the observations with calculated values. Because the flow exit area is an annulus, vorticity is shed at both the inner and outer edge of the jet. This results in a reduced circulation compared with the value calculated from slug theory accounting only for the outer edge. If the value of circulation obtained from laser particle imaging velocimetry is used in the slug model calculation of vortex ring velocity, the agreement is quite good. The vortex ring radius, which does not depend on the circulation, agrees well with predictions from the slug model.

Laser, light, and energy devices for cellulite and lipodystrophy.

PubMed

Peterson, Jennifer D; Goldman, Mitchel P

2011-07-01

Cellulite affects all races, and it is estimated that 85% of women older than 20 years have some degree of cellulite. Many currently accepted cellulite therapies target deficiencies in lymphatic drainage and microvascular circulation. Devices using radiofrequency, laser, and light-based energies, alone or in combination and coupled frequently with tissue manipulation, are available for improving cellulite. Laser assisted liposuction may improve cellulite appearance. Although improvement using these devices is temporary, it may last several months. Patients who want smoother skin with less visible cellulite can undergo a series of treatments and then return for additional treatments as necessary. Copyright © 2011 Elsevier Inc. All rights reserved.

New photoacoustic platform for early detection of circulating clots to prevent stroke and other fatal thromboembolic complications (Conference Presentation)

NASA Astrophysics Data System (ADS)

Carey, Kai A.

2017-03-01

Nearly 800,000 people in the U.S. experience an incident of stroke each year; 80% of these are first time occurrences and 87% are ischemic in nature. Someone dies of a stroke every few minutes in the U.S. but despite its prevalence there have been minimal advances in the early detection and screening of thromboembolic events, especially during patient post-operative periods or in genetically predisposed individuals. Environmental or genetic factors may disrupt the balance between coagulation and lysis of micro-thrombi in circulation and increase the risk of stroke. We introduced here a novel in vivo multicolor negative-contrast photoacoustic (PA) flow cytometry (PAFC ) platform with many innovations including customized high pulse repetition rate 1064 laser from IPG Photonics Corporation, powerful laser diode array, multichannel optical schematic, and time-resolved recording system. Using animal models, we verified the potential of this technology to detect small clots in relatively large vessels in vivo. If future clinical trials using a cost-effective, easy-to-use, safe, watch-like, wearable PA probe are successful, PAFC could provide breakthroughs in early monitoring of the growth in size and number of small clots that may predict and potentially prevent fatal thromboembolic complications. We also believe that this technology could be utilized to assess therapeutic benefits of anticoagulants and develop more efficient dosage in treatments by analyzing changes in the composition and frequency of micro-thrombi

Photoacoustic monitoring of circulating tumor cells released during medical procedures

NASA Astrophysics Data System (ADS)

Juratli, Mazen A.; Sarimollaoglu, Mustafa; Nedosekin, Dmitry A.; Galanzha, Ekaterina; Suen, James Y.; Zharov, Vladimir P.

2013-03-01

Many cancer deaths are related to metastasis to distant organs due to dissemination of circulating tumor cells (CTCs) shed from the primary tumor. For many years, oncologists believed some medical procedures may provoke metastasis; however, no direct evidence has been reported. We have developed a new, noninvasive technology called in vivo photoacoustic (PA) flow cytometry (PAFC), which provides ultrasensitive detection of CTCs. When CTCs with strongly light-absorbing intrinsic melanin pass through a laser beam aimed at a peripheral blood vessel, laser-induced acoustic waves from CTCs were detected using an ultrasound transducer. We focused on melanoma as it is one of the most metastatically aggressive malignancies. The goal of this research was to determine whether melanoma manipulation, like compression, incisional biopsy, or tumor excision, could enhance penetration of cancer cells from the primary tumor into the circulatory system. The ears of nude mice were inoculated with melanoma cells. Blood vessels were monitored for the presence of CTCs using in vivo PAFC. We discovered some medical procedures, like compression of the tumor, biopsy, and surgery may either initiate CTC release in the blood which previously contained no CTCs, or dramatically increased (10-30-fold) CTC counts above the initial level. Our results warn oncologists to use caution during physical examination, and surgery. A preventive anti-CTC therapy during or immediately after surgery, by intravenous drug administration could serve as an option to treat the resulting release of CTCs.

Gaseous-fuel nuclear reactor research for multimegawatt power in space

NASA Technical Reports Server (NTRS)

Thom, K.; Schneider, R. T.; Helmick, H. H.

1977-01-01

In the gaseous-fuel reactor concept, the fissile material is contained in a moderator-reflector cavity and exists in the form of a flowing gas or plasma separated from the cavity walls by means of fluid mechanical forces. Temperatures in excess of structural limitations are possible for low-specific-mass power and high-specific-impulse propulsion in space. Experiments have been conducted with a canister filled with enriched UF6 inserted into a beryllium-reflected cavity. A theoretically predicted critical mass of 6 kg was measured. The UF6 was also circulated through this cavity, demonstrating stable reactor operation with the fuel in motion. Because the flowing gaseous fuel can be continuously processed, the radioactive waste in this type of reactor can be kept small. Another potential of fissioning gases is the possibility of converting the kinetic energy of fission fragments directly into coherent electromagnetic radiation, the nuclear pumping of lasers. Numerous nuclear laser experiments indicate the possibility of transmitting power in space directly from fission energy. The estimated specific mass of a multimegawatt gaseous-fuel reactor power system is from 1 to 5 kg/kW while the companion laser-power receiver station would be much lower in specific mass.

Library Circulation Systems -- An Overview.

ERIC Educational Resources Information Center

Surace, Cecily J.

The model circulation system outlined is an on-line real time system in which the circulation file is created from the shelf list and the terminal inquiry system includes the capability to query and browse through the bibliographic system and the circulation subsystem together to determine the availability for circulation of specific documents, or…

A gravity model for crustal dynamics (GEM-L2)

NASA Technical Reports Server (NTRS)

Lerch, F. J.; Klosko, S. M.; Patel, G. B.; Wagner, C. A.

1985-01-01

The Laser Geodynamics Satellite (Lageos) was the first NASA satellite which was placed into orbit exclusively for laser ranging applications. Lageos was designed to permit extremely accurate measurements of the earth's rotation and the movement of the tectonic plates. The Goddard earth model, GEM-L2, was derived mainly on the basis of the precise laser ranging data taken on many satellites. Douglas et al. (1984) have demonstrated the utility of GEM-L2 in detecting the broadest ocean circulations. As Lageos data constitute the most extensive set of satellite laser observations ever collected, the incorporation of 2-1/2 years of these data into the Goddard earth models (GEM) has substantially advanced the geodynamical objectives. The present paper discusses the products of the GEM-L2 solution.

A laser-based technology for fabricating a soda-lime glass based microfluidic device for circulating tumour cell capture.

PubMed

Nieto, Daniel; Couceiro, Ramiro; Aymerich, Maria; Lopez-Lopez, Rafael; Abal, Miguel; Flores-Arias, María Teresa

2015-10-01

We developed a laser-based technique for fabricating microfluidic microchips on soda-lime glass substrates. The proposed methodology combines a laser direct writing, as a manufacturing tool for the fabrication of the microfluidics structures, followed by a post-thermal treatment with a CO2 laser. This treatment will allow reshaping and improving the morphological (roughness) and optical qualities (transparency) of the generated microfluidics structures. The use of lasers commonly implemented for material processing makes this technique highly competitive when compared with other glass microstructuring approaches. The manufactured chips were tested with tumour cells (Hec 1A) after being functionalized with an epithelial cell adhesion molecule (EpCAM) antibody coating. Cells were successfully arrested on the pillars after being flown through the device giving our technology a translational application in the field of cancer research. Copyright © 2015 Elsevier B.V. All rights reserved.

Fast, label-free super-resolution live-cell imaging using rotating coherent scattering (ROCS) microscopy

NASA Astrophysics Data System (ADS)

Jünger, Felix; Olshausen, Philipp V.; Rohrbach, Alexander

2016-07-01

Living cells are highly dynamic systems with cellular structures being often below the optical resolution limit. Super-resolution microscopes, usually based on fluorescence cell labelling, are usually too slow to resolve small, dynamic structures. We present a label-free microscopy technique, which can generate thousands of super-resolved, high contrast images at a frame rate of 100 Hertz and without any post-processing. The technique is based on oblique sample illumination with coherent light, an approach believed to be not applicable in life sciences because of too many interference artefacts. However, by circulating an incident laser beam by 360° during one image acquisition, relevant image information is amplified. By combining total internal reflection illumination with dark-field detection, structures as small as 150 nm become separable through local destructive interferences. The technique images local changes in refractive index through scattered laser light and is applied to living mouse macrophages and helical bacteria revealing unexpected dynamic processes.

Fast, label-free super-resolution live-cell imaging using rotating coherent scattering (ROCS) microscopy

PubMed Central

Jünger, Felix; Olshausen, Philipp v.; Rohrbach, Alexander

2016-01-01

Living cells are highly dynamic systems with cellular structures being often below the optical resolution limit. Super-resolution microscopes, usually based on fluorescence cell labelling, are usually too slow to resolve small, dynamic structures. We present a label-free microscopy technique, which can generate thousands of super-resolved, high contrast images at a frame rate of 100 Hertz and without any post-processing. The technique is based on oblique sample illumination with coherent light, an approach believed to be not applicable in life sciences because of too many interference artefacts. However, by circulating an incident laser beam by 360° during one image acquisition, relevant image information is amplified. By combining total internal reflection illumination with dark-field detection, structures as small as 150 nm become separable through local destructive interferences. The technique images local changes in refractive index through scattered laser light and is applied to living mouse macrophages and helical bacteria revealing unexpected dynamic processes. PMID:27465033

Comparison of cerebral microcirculation of alloxan diabetes and healthy mice using laser speckle contrast imaging

NASA Astrophysics Data System (ADS)

Timoshina, Polina A.; Shi, Rui; Zhang, Yang; Zhu, Dan; Semyachkina-Glushkovskaya, Oxana V.; Tuchin, Valery V.; Luo, Qingming

2015-03-01

The study of blood microcirculation is one of the most important problems of the medicine. This paper presents results of experimental study of cerebral blood flow microcirculation in mice with alloxan-induced diabetes using Temporal Laser Speckle Imaging (TLSI). Additionally, a direct effect of glucose water solution (concentration 20% and 45%) on blood flow microcirculation was studied. In the research, 20 white laboratory mice weighing 20-30 g were used. The TLSI method allows one to investigate time dependent scattering from the objects with complex dynamics, since it possesses greater temporal resolution. Results show that in brain of animal diabetic group diameter of sagittal vein is increased and the speed of blood flow reduced relative to the control group. Topical application of 20%- or 45%-glucose solutions also causes increase of diameter of blood vessels and slows down blood circulation. The results obtained show that diabetes development causes changes in the cerebral microcirculatory system and TLSI techniques can be effectively used to quantify these alterations.

Laser mimicking mosquito bites for skin delivery of malaria sporozoite vaccines.

PubMed

Zhou, Chang; Chen, Xinyuan; Zhang, Qi; Wang, Ji; Wu, Mei X

2015-04-28

Immunization with radiation-attenuated sporozoites (RAS) via mosquito bites has been shown to induce sterile immunity against malaria in humans, but this route of vaccination is neither practical nor ethical. The importance of delivering RAS to the liver through circulation in eliciting immunity against this parasite has been recently verified by human studies showing that high-level protection was achieved only by intravenous (IV) administration of RAS, not by intradermal (ID) or subcutaneous (SC) vaccination. Here, we report in a murine model that ID inoculation of RAS into laser-illuminated skin confers immune protection against malarial infection almost as effectively as IV immunization. Brief illumination of the inoculation site with a low power 532 nm Nd:YAG laser enhanced the permeability of the capillary beneath the skin, owing to hemoglobin-specific absorbance of the light. The increased blood vessel permeability appeared to facilitate an association of RAS with blood vessel walls by an as-yet-unknown mechanism, ultimately promoting a 7-fold increase in RAS entering circulation and reaching the liver over ID administration. Accordingly, ID immunization of RAS at a laser-treated site stimulated much stronger sporozoite-specific antibody and CD8(+)IFN-γ(+) T cell responses than ID vaccination and provided nearly full protection against malarial infection, whereas ID immunization alone was ineffective. This novel, safe, and convenient strategy to augment efficacy of ID sporozoite-based vaccines warrants further investigation in large animals and in humans. Copyright © 2015 Elsevier B.V. All rights reserved.

Laser mimicking mosquito bites for skin delivery of malaria sporozoite vaccines

PubMed Central

Zhou, Chang; Chen, Xinyuan; Zhang, Qi; Wang, Ji; Wu, Mei X.

2015-01-01

Immunization with radiation-attenuated sporozoites (RAS) via mosquito bites has been shown to induce sterile immunity against malaria in humans, but this route of vaccination is neither practical nor ethical. The importance of delivering RAS to the liver through circulation in eliciting immunity against this parasite has been recently verified by human studies showing that high-level protection was achieved only by intravenous (IV) administration of RAS, but not by intradermal (ID) or subcutaneous (SC) vaccination. Here, we report in a murine model that ID inoculation of RAS into laser-illuminated skin confers immune protection against malarial infection almost as effectively as IV immunization. Brief illumination of the inoculation site with a low power 532 nm Nd:YAG laser enhanced the permeability of the capillary beneath the skin, owing to hemoglobin-specific absorbance of the light. The increased blood vessel permeability appeared to facilitate an association of RAS with blood vessel walls by an as-yet-unknown mechanism, ultimately promoting a 7-fold increase in RAS entering circulation and reaching the liver over ID administration. Accordingly, ID immunization of RAS at a laser-treated site stimulated much stronger sporozoite-specific antibody and CD8+IFN-γ+ T cell responses than ID vaccination and provided nearly full protection against malarial infection, whereas ID immunization alone was ineffective. This novel, safe, and convenient strategy to augment efficacy of ID sporozoite-based vaccines warrants further investigation in big animals and in humans. PMID:25725360

The e-beam sustained CO2 laser amplifier

NASA Technical Reports Server (NTRS)

Brown, M. J.; Shaw, S. R.; Evans, M. H.; Smith, I. M.; Holman, W.

1990-01-01

The design features of an e-beam sustained CO2 amplifier are described. The amplifier is designed specifically as a catalyst test-bed to study the performance of room temperature precious metal CO-oxidation catalysts under e-beam sustained operation. The amplifier has been designed to provide pulse durations of 30 microseconds in a discharge volume of 2 litres. With a gas flow velocity of 2 metres per second, operation at repetition rates of 10 Hz is accommodated. The system is designed for sealed-off operation and a catalyst bed is housed in the gas circulation system downstream from the discharge region. CO and oxygen monitors are used for diagnosis of gas composition in the amplifier so that catalyst performance can be monitored in situ during sealed lifetests.

Microscopic mechanism analyses on influence of metabolism of erythrocyte membrane-lipid etc. by LLLIB

NASA Astrophysics Data System (ADS)

Xu, Lin; Zhang, Canbang; Wen, Yuanbin; Liu, Shuxiao; Zhou, Lingyun

2009-08-01

Some cases with cerebral infarction were treated by He-Ne laser irradiation on blood. In the treatment before and after, membrane-cholesterol(C)/membrane-phosphatide(P), membrane fluidity(F) and deformability of erythrocyte were determined. The results showed that low level laser irradiation on blood (LLLIB) can sure reduce the ratio of (C)/(P), can heighten fluidity and improve deformability of erythrocyte .Thus the metabolism ability of erythrocyte membrane-lipid ,the blood circulation and the properties of hemorheology can be improved. In this paper, the microscopic mechanism of those aforesaid action effects by low level laser irradiation on blood were analyzed by means of Quantum theory and some corresponding models.

Real-Time Demonstration of Split Skin Graft Inosculation and Integra Dermal Matrix Neovascularization Using Confocal Laser Scanning Microscopy

PubMed Central

Greenwood, John; Amjadi, Mahyar; Dearman, Bronwyn; Mackie, Ian

2009-01-01

Objectives: During the first 48 hours after placement, an autograft “drinks” nutrients and dissolved oxygen from fluid exuding from the underlying recipient bed (“plasmatic imbibition”). The theory of inosculation (that skin grafts subsequently obtain nourishment via blood vessel “anastomosis” between new vessels invading from the wound bed and existing graft vessels) was hotly debated from the late 19th to mid-20th century. This study aimed to noninvasively observe blood flow in split skin grafts and Integra™ dermal regeneration matrix to provide further proof of inosculation and to contrast the structure of vascularization in both materials, reflecting mechanism. Methods: Observations were made both clinically and using confocal microscopy on normal skin, split skin graft, and Integra™. The VivaScope™ allows noninvasive, real-time, in vivo images of tissue to be obtained. Results: Observations of blood flow and tissue architecture in autologous skin graft and Integra™ suggest that 2 very different processes are occurring in the establishment of circulation in each case. Inosculation provides rapid circulatory return to skin grafts whereas slower neovascularization creates an unusual initial Integra™ circulation. Conclusions: The advent of confocal laser microscopy like the VivaScope 1500™, together with “virtual” journals such as ePlasty, enables us to provide exciting images and distribute them widely to a “reading” audience. The development of the early Integra™ vasculature by neovascularization results in a large-vessel, high-volume, rapid flow circulation contrasting markedly from the inosculatory process in skin grafts and the capillary circulation in normal skin and merits further (planned) investigation. PMID:19787028

Multi-Component, Multi-Point Interferometric Rayleigh/Mie Doppler Velocimeter

NASA Technical Reports Server (NTRS)

Danehy, Paul M.; Lee, Joseph W.; Bivolaru, Daniel

2012-01-01

An interferometric Rayleigh scattering system was developed to enable the measurement of multiple, orthogonal velocity components at several points within very-high-speed or high-temperature flows. The velocity of a gaseous flow can be optically measured by sending laser light into the gas flow, and then measuring the scattered light signal that is returned from matter within the flow. Scattering can arise from either gas molecules within the flow itself, known as Rayleigh scattering, or from particles within the flow, known as Mie scattering. Measuring Mie scattering is the basis of all commercial laser Doppler and particle imaging velocimetry systems, but particle seeding is problematic when measuring high-speed and high-temperature flows. The velocimeter is designed to measure the Doppler shift from only Rayleigh scattering, and does not require, but can also measure, particles within the flow. The system combines a direct-view, large-optic interferometric setup that calculates the Doppler shift from fringe patterns collected with a digital camera, and a subsystem to capture and re-circulate scattered light to maximize signal density. By measuring two orthogonal components of the velocity at multiple positions in the flow volume, the accuracy and usefulness of the flow measurement increase significantly over single or nonorthogonal component approaches.

Microgravity Diode Laser Spectroscopy Measurements in a Reacting Vortex Ring

NASA Technical Reports Server (NTRS)

Chen, Shin-Juh; Dahm, Werner J. A.; Silver, Joel A.; Piltch, Nancy D.; VanderWal, R. (Technical Monitor)

2001-01-01

The technique of Diode Laser Spectroscopy (DLS) with wavelength modulation is utilized to measure the concentration of methane in reacting vortex rings under microgravity conditions. From the measured concentration of methane, other major species such as water, carbon dioxide, nitrogen, and oxygen can be easily computed under the assumption of equilibrium chemistry with an iterative method called ITAC (Iterative Temperature with Assumed Chemistry). The conserved scalar approach in modelling the coupling between fluid dynamics and combustion is utilized to represent the unknown variables in terms of the mixture fraction and scalar dissipation rate in conjunction with ITAC. Post-processing of the DLS and the method used to compute the species concentration are discussed. From the flame luminosity results, ring circulation appears to increase the fuel consumption rate inside the reacting vortex ring and the flame height for cases with similar fuel volumes but different ring circulations. The concentrations of methane, water, and carbon dioxide agree well with available results from numerical simulations.

40nm tunable multi-wavelength fiber laser

NASA Astrophysics Data System (ADS)

Jia, Qingsong; Wang, Tianshu; Zhang, Peng; Dong, Keyan; Jiang, Huilin

2014-12-01

A Brillouin-Erbium multi-wavelength tunable fiber laser at C-band is demostrated. A 10 km long singlemode fiber(SMF), a 6 m long Erbium-doped fiber, two couplers, a wavelength division multiplexer, a isolator, an optical circulator, a 980nm pump laser and a narrow linewidth tunable laser are included in the structure. A segment of 10 km-long single-mode fiber (SMF) between the two ports of a 1×2 coupler is used as Brillouin gain. Ebiumdoped fiber amplifier (EDFA) consists of a segment of 6m er-doped fiber pumped by 980nm laser dioder . A narrow linewidth tunable laser from 1527 to 1607 nm as Brillouin bump, At the Brillouin pump power of 8mW and the 980 nm pump power of 400 mw, 16 output channels with 0.08 nm spacing and tuning range of 40 nm from 1527 nm to 1567 nm are achieved. We realize the tunable output of wavelength by adjusting the 980 nm pump power and the Brillouin pump wavelength. Stability of the multiwavelength fiber laser is also observed.

Perspective of laser-induced plasma ignition of hydrocarbon fuel in Scramjet engine

NASA Astrophysics Data System (ADS)

Yang, Leichao; Li, Xiaohui; Liang, Jianhan; Yu, Xin; Li, Xipeng

2016-01-01

Laser-induced plasma ignition of an ethylene fuelled cavity was successfully conducted in a model scramjet engine combustor. The ethylene was injected 10mm upstream of cavity flameholder from 3 orifices 60 degree inclined relative to freestream direction. The 1064nm laser beam, from a Q-switched Nd:YAG laser source running at 3Hz and 200mJ per pulse, was focused into cavity for ignition. High speed photography was used to capture the transient ignition process. The laser-induced gas breakdown, flame kernel generation and propagation were all recorded and ensuing stable supersonic combustion was established in cavity. The flame kernel is found rotating anti-clockwise and gradually moves upwards as the entrainment of circulation flow in cavity. The flame is then stretched from leading edge to trailing edge to fully fill the entire cavity. Eventually, a stable combustion is achieved roughly 900μs after the laser pulse. The results show promising potentials for practical application. The perspective of laser-induced plasma ignition of hydrocarbon fuel in scramjet engine is outlined.

Nd:YLF laser for airborne/spaceborne laser ranging

NASA Technical Reports Server (NTRS)

Dallas, Joseph L.; Selker, Mark D.

1993-01-01

In order to meet the need for light weight, long lifetime, efficient, short pulse lasers, a diode-pumped, Nd:YLF oscillator and regenerative amplifier is being developed. The anticipated output is 20 mJ per 10 picosecond pulse, running at a repetition rate of 40 Hz. The fundamental wavelength is at 1047 nm. The oscillator is pumped by a single laser diode bar and mode locked using an electro-optic, intra-cavity phase modulator. The output from the oscillator is injected as a seed into the regenerative amplifier. The regenerative amplifier laser crystal is optically pumped by two 60W quasi-cw laser diode bars. Each diode is collimated using a custom designed micro-lens bar. The injected 10 ps pulse from the oscillator is kept circulating within the regenerative amplifier until this nanojoule level seed pulse is amplified to 2-3 millijoules. At this point the pulse is ejected and sent on to a more standard single pass amplifier where the energy is boosted to 20 mJ. The footprint of the entire laser (oscillator-regenerative amplifier-amplifier) will fit on a 3 by 4 ft. optical pallet.

Quantification of wind flow in the European Mars Simulation Wind Tunnel Facility

NASA Astrophysics Data System (ADS)

Holstein-Rathlou, C.; Merrison, J. P.; Iversen, J. J.; Nornberg, P.

2012-04-01

We present the European Mars Simulation Wind Tunnel facility, a unique prototype facility capable of simulating a wide range of environmental conditions, such as those which can be found at the surface of Earth or Mars. The chamber complements several other large-scale simulation facilities at Aarhus University, Denmark. The facility consists of a 50 m3 environmental chamber capable of operating at low pressure (0.02 - 1000 mbar) and cryogenic temperatures (-130 °C up to +60 °C). This chamber houses a re-circulating wind tunnel capable of generating wind speeds up to 25 m/s and has a dust injection system that can produce suspended particulates (aerosols). It employs a unique LED based optical illumination system (solar simulator) and an advanced network based control system. Laser based optoelectronic instrumentation is used to quantify and monitor wind flow, dust suspension and deposition. This involves a commercial Laser Doppler Anemometer (LDA) and a Particle Dynamics Analysis receiver (PDA), which are small laser based instruments specifically designed for measuring wind speed and sizes of particles situated in a wind flow. Wind flow calibrations will be performed with the LDA system and presented. Pressure and temperature calibrations will follow in order to enable the facility to be used for the testing, development, calibration and comparison of e.g. meteorological sensors under a wide range of environmental conditions as well as multi-disciplinary scientific studies. The wind tunnel is accessible to international collaborators and space agencies for instrument testing, calibration and qualification. It has been financed by the European Space Agency (ESA) as well as the Aarhus University Science Faculty and the Villum Kann Rasmussen Foundation.

Comparison of four lasers (λ = 650, 808, 980, and 1075 nm) for noninvasive creation of deep subsurface lesions in tissue

NASA Astrophysics Data System (ADS)

Chang, Chun-Hung; Wilson, Christopher R.; Fried, Nathaniel M.

2015-07-01

Lasers have been used in combination with applied cooling methods to preserve superficial skin layers (100's μm's) during cosmetic surgery. Preservation of a thicker tissue surface layer (millimeters) may also allow development of other noninvasive laser procedures. We are exploring noninvasive therapeutic laser applications in urology (e.g. laser vasectomy and laser treatment of female stress urinary incontinence), which require surface tissue preservation on the millimeter scale. In this preliminary study, four lasers were compared for noninvasive creation of deep subsurface thermal lesions. Laser energy from three diode lasers (650, 808, and 980 nm) and a Ytterbium fiber laser (1075 nm) was delivered through a custom built, side-firing, laser probe with integrated cooling. An alcohol-based solution at -5 °C was circulated through a flow cell, cooling a sapphire window, which in turn cooled the tissue surface. The probe was placed in contact with porcine liver tissue, ex vivo, kept hydrated in saline and maintained at ~ 35 °C. Incident laser power was 4.2 W, spot diameter was 5.3 mm, and treatment time was 60 s. The optimal laser wavelength tested for creation of deep subsurface thermal lesions during contact cooling of tissues was 1075 nm, which preserved a surface layer of ~ 2 mm. The Ytterbium fiber laser provides a compact, low maintenance, and high power alternative laser source to the Neodymium:YAG laser for noninvasive thermal therapy.

Spanwise loading distribution and wake velocity surveys of a semi-span wing

NASA Technical Reports Server (NTRS)

Felker, F. F., III; Piziali, R. A.; Gall, J. K.

1982-01-01

The spanwise distribution of bound circulation on a semi-span wing and the flow velocities in its wake were measured in a wind tunnel. Particular attention was given to documenting the flow velocities in and around the development tip vortex. A two-component laser velocimeter was used to make the velocity measurements. The spanwise distribution of bound circulation, three components of the time-averaged velocities throughout the near wake their standard deviations, and the integrated forces and moments on a metric tip as measured by an internal strain gage balance are presented without discussion.

Multifunctional hyaluronic acid modified graphene oxide loaded with mitoxantrone for overcoming drug resistance in cancer

NASA Astrophysics Data System (ADS)

Hou, Lin; Feng, Qianhua; Wang, Yating; Yang, Xiaomin; Ren, Junxiao; Shi, Yuyang; Shan, Xiaoning; Yuan, Yujie; Wang, Yongchao; Zhang, Zhenzhong

2016-01-01

Multifunctional nanosheets (HA-GO/Pluronic) with targeted chemo-photothermal properties were successfully developed for controlled delivery of mitoxantrone (MIT) to overcome multidrug resistance (MDR). In vitro release profiles displayed that both an acidic environment and a NIR laser could trigger and accelerate the release of a drug, which ensured nanosheets were stable in blood circulation and released MIT within tumor cells under laser irradiation. HA-GO/Pluronic nanosheets were taken up into MCF-7/ADR cells via receptor-mediated endocytosis, which further facilitated escapement of P-gp efflux. Compared with MIT solution, MIT/HA-GO/Pluronic showed greater cytotoxicity and increase in cellular MIT accumulation in MCF-7/ADR cells. Cell apoptosis and cell cycle arrest studies also revealed that MIT/HA-GO/Pluronic was more potent than MIT/GO/Pluronic and MIT solution. The anticancer efficacy in vivo was evaluated in MCF-7 and MCF-7/ADR-bearing mice, and inhibition of tumors by MIT/HA-GO/Pluronic with NIR laser irradiation was the most effective among all MIT formulations. In summary, the MIT/HA-GO/Pluronic system had striking functions such as P-gp reversible inhibitor and anticancer efficacy, and could present a promising platform for drug-resistant cancer treatment.

Japanese vegetation lidar (MOLI) on ISS (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kimura, Toshiyoshi; Imai, Tadashi; Sakaizawa, Daisuke; Murooka, Junpei

2016-10-01

Multi-footprint Observation LIDAR and Imager (MOLI) is a candidate mission for International Space Station - Japanese Experiment Module. The mission objective MOLI is to manage forest and to be a good calibrator for evaluation of forest biomass using satellite instrument such as L-band SAR. SAR is the powerful tool to evaluate biomass globally. However it has some signal saturation over 100 t/ha biomass measurement, whereas Vegetation LIDAR is expected to measure higher mass precisely. MOLI is designed to evaluate forest biomass with high accuracy. An imager, that is equipped together in good registration with LIDAR, will help to understand the situation of target forest. Also two simultaneous Laser beams from MOLI will calibrate the relief effect, which affects the precision of canopy height extremely. Using together with L-band SAR observation data or multispectral image, it is expected to have a good "wall to wall" biomass map with its phonological information. Such MOLI observation capability is so important, because both quantity and quality evaluation of biomass are essential for carbon circulation system understandings. Currently, as a key technical development, LASER Transmitters for MOLI is under test in vacuum condition. Its power is 40mJ and PRF is 150Hz. Pressure vessel design for LIDAR transmitter is supressing Laser induced contamination effect. MOLI is now under study towards around 2020 operation.

Benefits of low-power lasers on oral soft tissue

NASA Astrophysics Data System (ADS)

Eduardo, Carlos d. P.; Cecchini, Silvia C. M.; Cecchini, Renata C.

1996-04-01

The last five years have represented a great advance in relation to laser development. Countries like Japan, United States, French, England, Israel and others, have been working on the association of researches and clinical applications, in the field of laser. Low power lasers like He-Ne laser, emitting at 632,8 nm and Ga-As-Al laser, at 790 nm, have been detached acting not only as a coadjutant but some times as an specific treatment. Low power lasers provide non thermal effect at wavelengths believed to stimulate circulation and cellular activity. These lasers have been used to promote wound healing and reduce inflammation edema and pain. This work presents a five year clinical study with good results related to oral tissue healing. Oral cavity lesions, like herpes and aphthous ulcers were irradiated with Ga-Al- As laser. In both cases, an excellent result was obtained. The low power laser application decrease the painful sintomatology immediately and increase the reparation process of these lesions. An excellent result was obtained with application of low power laser in herpetic lesions associated with a secondary infection situated at the lip commissure covering the internal tissue of the mouth. The healing occurred after one week. An association of Ga-Al-As laser and Nd:YAG laser have been also proven to be good therapy for these kind of lesions. This association of low and high power laser has been done since 1992 and it seems to be a complement of the conventional therapies.

Library Circulation Systems: An Overview

ERIC Educational Resources Information Center

Surace, Cecily J.

1972-01-01

The model circulation system outlined is an on-line real time system in which the circulation file is created from the shelf list. The model extends beyond the operational limits of most existing circulation systems and can be considered a reflection of the current state of the art. (36 references) (Author/NH)

Electrical Lumped Model Examination for Load Variation of Circulation System

NASA Astrophysics Data System (ADS)

Koya, Yoshiharu; Ito, Mitsuyo; Mizoshiri, Isao

Modeling and analysis of the circulation system enables the characteristic decision of circulation system in the body to be made. So, many models of circulation system have been proposed. But, they are complicated because the models include a lot of elements. Therefore, we proposed a complete circulation model as a lumped electrical circuit, which is comparatively simple. In this paper, we examine the effectiveness of the complete circulation model as a lumped electrical circuit. We use normal, angina pectoris, dilated cardiomyopathy and myocardial infarction for evaluation of the ventricular contraction function.

Intrapulpal Temperature Increase During Er:YAG Laser-Aided Debonding of Ceramic Brackets.

PubMed

Yilanci, Hilal; Yildirim, Zeynep Beyza; Ramoglu, Sabri Ilhan

2017-04-01

The purpose of this study was to evaluate the temperature changes in the pulp chamber while using a newly introduced application of Er:YAG laser to debond ceramic brackets in a study model with a pulpal circulation with and without thermocycled samples. An esthetic alternative to stainless steel brackets, ceramic brackets have been proposed. However, because of their low fracture resistance and high bond strengths, ceramic brackets can cause a problem when they are being removed using conventional techniques. Experimental Groups A and B were established for samples with or without thermocycling. The same 20 maxillary central incisor and 20 premolar teeth were used in both groups. Pulpal blood microcirculation was simulated using an apparatus described in a previous study. Monocrystalline brackets were bonded by using Transbond XT. In Group A, brackets were debonded using the Er:YAG laser (600 mJ, 2 Hz, long pulse, and no air or water spray) after being stored in distilled water for 24 h. In Group B, brackets were debonded using the same laser system as that used in Group A after being stored in distilled water for 24 h and then thermocycled for a total of 5000 cycles between 5°C and 55°C. The laser irradiation duration and intrapulpal temperature changes were measured. In Group B, the intrapulpal temperature increase of the central incisors was significantly higher than that of the premolar teeth. In the central incisor and premolar teeth groups, there were no statistically significant difference between Groups A and B (p > 0.05). A positive correlation was found between laser irradiation duration and temperature increase (p < 0.01). The use of Er:YAG laser is an effective method for debonding the monocrystalline ceramic brackets. This method can be used safely under the consideration of intrapulpal temperature changes.

Polymeric capsule-cushioned leukocyte cell membrane vesicles as a biomimetic delivery platform

NASA Astrophysics Data System (ADS)

Gao, Changyong; Wu, Zhiguang; Lin, Zhihua; Lin, Xiankun; He, Qiang

2016-02-01

We report a biomimetic delivery of microsized capsule-cushioned leukocyte membrane vesicles (CLMVs) through the conversion of freshly reassembled leukocyte membrane vesicles (LMVs), including membrane lipids and membrane-bound proteins onto the surface of layer-by-layer assembled polymeric multilayer microcapsules. The leukocyte membrane coating was verified by using electron microscopy, a quartz crystal microbalance, dynamic light scattering, and confocal laser scanning microscopy. The resulting CLMVs have the ability to effectively evade clearance by the immune system and thus prolong the circulation time in mice. Moreover, we also show that the right-side-out leukocyte membrane coating can distinctly improve the accumulation of capsules in tumor sites through the molecular recognition of membrane-bound proteins of CLMVs with those of tumor cells in vitro and in vivo. The natural cell membrane camouflaged polymeric multilayer capsules with the immunosuppressive and tumor-recognition functionalities of natural leukocytes provide a new biomimetic delivery platform for disease therapy.We report a biomimetic delivery of microsized capsule-cushioned leukocyte membrane vesicles (CLMVs) through the conversion of freshly reassembled leukocyte membrane vesicles (LMVs), including membrane lipids and membrane-bound proteins onto the surface of layer-by-layer assembled polymeric multilayer microcapsules. The leukocyte membrane coating was verified by using electron microscopy, a quartz crystal microbalance, dynamic light scattering, and confocal laser scanning microscopy. The resulting CLMVs have the ability to effectively evade clearance by the immune system and thus prolong the circulation time in mice. Moreover, we also show that the right-side-out leukocyte membrane coating can distinctly improve the accumulation of capsules in tumor sites through the molecular recognition of membrane-bound proteins of CLMVs with those of tumor cells in vitro and in vivo. The natural cell membrane camouflaged polymeric multilayer capsules with the immunosuppressive and tumor-recognition functionalities of natural leukocytes provide a new biomimetic delivery platform for disease therapy. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr08407e

Longitudinal studies on the microcirculation around the TheraCyte immunoisolation device, using the laser Doppler technique.

PubMed

Rafael, E; Gazelius, B; Wu, G S; Tibell, A

2000-01-01

Encapsulation of cellular grafts in an immunoisolation membrane device may make it possible to perform transplantation without having to give immunosuppressive drugs. A common problem is the development of an avascular fibrotic zone around the implants, leading to impaired graft survival. The TheraCyte macroencapsulation device has therefore been designed to facilitate neovascularization of the device's surface. In this study, we evaluated the microcirculation around empty TheraCyte devices implanted SC in rats at various times after implantation, using a laser Doppler probe introduced via the device port. Studies were performed on day 1 or at 1, 2, and 4 weeks or at 2, 3, and 12 months after implantation. The mean flow was 158+/-42, 148+/-50, 133+/-28, 72+/-17, 138+/-41, 165+/-43, and 160+/-29 perfusion units (PU), respectively. Thus, the microcirculation around the device was significantly reduced at 4 weeks after implantation (p < 0.01) while, from 2 months onwards the circulation had improved and did not differ significantly from that on day 1. The present study shows time-related changes in the microcirculatory flow around TheraCyte macroencapsulation devices that agree with our previous microdialysis studies on in vivo exchange of insulin and glucose between the device and the circulation. Laser Doppler flowmetry seems to provide a reliable technique for screening blood perfusion around macroencapsulation devices.

The effects of conventional extracorporeal circulation versus miniaturized extracorporeal circulation on microcirculation during cardiopulmonary bypass-assisted coronary artery bypass graft surgery.

PubMed

Yuruk, Koray; Bezemer, Rick; Euser, Mariska; Milstein, Dan M J; de Geus, Hilde H R; Scholten, Evert W; de Mol, Bas A J M; Ince, Can

2012-09-01

OBJECTIVES To reduce the complications associated with cardiopulmonary bypass (CPB) during cardiac surgery, many modifications have been made to conventional extracorporeal circulation systems. This trend has led to the development of miniaturized extracorporeal circulation systems. Cardiac surgery using conventional extracorporeal circulation systems has been associated with significantly reduced microcirculatory perfusion, but it remains unknown whether this could be prevented by an mECC system. Here, we aimed to test the hypothesis that microcirculatory perfusion decreases with the use of a conventional extracorporeal circulation system and would be preserved with the use of an miniaturized extracorporeal circulation system. METHODS Microcirculatory density and perfusion were assessed using sublingual side stream dark-field imaging in patients undergoing on-pump coronary artery bypass graft (CABG) surgery before, during and after the use of either a conventional extracorporeal circulation system (n = 10) or a miniaturized extracorporeal circulation system (n = 10). In addition, plasma neutrophil gelatinase-associated lipocalin and creatinine levels and creatinine clearance were assessed up to 5 days post-surgery to monitor renal function. RESULTS At the end of the CPB, one patient in the miniaturized extracorporeal circulation-treated group and five patients in the conventional extracorporeal circulation-treated group received one bag of packed red blood cells (300 ml). During the CPB, the haematocrit and haemoglobin levels were slightly higher in the miniaturized extracorporeal circulation-treated patients compared with the conventional extracorporeal circulation-treated patients (27.7 ± 3.3 vs 24.7 ± 2.0%; P = 0.03; and 6.42 ± 0.75 vs 5.41 ± 0.64 mmol/l; P < 0.01). The density of perfused vessels with a diameter <25 µm (i.e. perfused vessel density) decreased slightly in the conventional extracorporeal circulation-treated group from 16.4 ± 3.8 to 12.8 ± 3.3 mm/mm(2) (P < 0.01) and remained stable in the miniaturized extracorporeal circulation-treated group (16.3 ± 2.7 and 15.2 ± 2.9 mm/mm(2) before and during the pump, respectively). Plasma neutrophil gelatinase-associated lipocalin levels were increased following the use of extracorporeal circulation in both groups, and no differences were observed between the groups. Plasma creatinine levels and creatinine clearance were not affected by CABG surgery or CPB. CONCLUSIONS The results from this relatively small study suggest that the use of the miniaturized extracorporeal circulation system is associated with a statistically significant (but clinically insignificant) reduction in haemodilution and microcirculatory hypoperfusion compared with the use of the conventional extracorporeal circulation system.

10.1142/9781911299660_fmatter years Laser Interaction and Related Plasma Phenomena (lirpp Vol. 13)

NASA Astrophysics Data System (ADS)

Hora, Heinrich

2016-10-01

When these proceedings of 13th international conference LASER INTERACTION AND RELATED PLASMA PHENOMENA (LIRPP) will be circulated in 1998, it is just 30 years that this conference series began. Professor Miley asked me to present some thoughts at this occasion since I am involved from the beginning to 1991 a director and then as emeritus director. The conferences were in the following years 1969, 1971, 1973, 1976, 1979, 1982, 1985, 1987, 1989, 1991, 1993, 1995 and 1997 and reference to each of the conferences is simply given by the year in brackets...

Rapid multi-wavelength optical assessment of circulating blood volume without a priori data

NASA Astrophysics Data System (ADS)

Loginova, Ekaterina V.; Zhidkova, Tatyana V.; Proskurnin, Mikhail A.; Zharov, Vladimir P.

2016-03-01

The measurement of circulating blood volume (CBV) is crucial in various medical conditions including surgery, iatrogenic problems, rapid fluid administration, transfusion of red blood cells, or trauma with extensive blood loss including battlefield injuries and other emergencies. Currently, available commercial techniques are invasive and time-consuming for trauma situations. Recently, we have proposed high-speed multi-wavelength photoacoustic/photothermal (PA/PT) flow cytometry for in vivo CBV assessment with multiple dyes as PA contrast agents (labels). As the first step, we have characterized the capability of this technique to monitor the clearance of three dyes (indocyanine green, methylene blue, and trypan blue) in an animal model. However, there are strong demands on improvements in PA/PT flow cytometry. As additional verification of our proof-of-concept of this technique, we performed optical photometric CBV measurements in vitro. Three label dyes—methylene blue, crystal violet and, partially, brilliant green—were selected for simultaneous photometric determination of the components of their two-dye mixtures in the circulating blood in vitro without any extra data (like hemoglobin absorption) known a priori. The tests of single dyes and their mixtures in a flow system simulating a blood transfusion system showed a negligible difference between the sensitivities of the determination of these dyes under batch and flow conditions. For individual dyes, the limits of detection of 3×10-6 M‒3×10-6 M in blood were achieved, which provided their continuous determination at a level of 10-5 M for the CBV assessment without a priori data on the matrix. The CBV assessment with errors no higher than 4% were obtained, and the possibility to apply the developed procedure for optical photometric (flow cytometry) with laser sources was shown.

The microbiological quality of air improves when using air conditioning systems in cars.

PubMed

Vonberg, Ralf-Peter; Gastmeier, Petra; Kenneweg, Björn; Holdack-Janssen, Hinrich; Sohr, Dorit; Chaberny, Iris F

2010-06-01

Because of better comfort, air conditioning systems are a common feature in automobiles these days. However, its impact on the number of particles and microorganisms inside the vehicle--and by this its impact on the risk of an allergic reaction--is yet unknown. Over a time period of 30 months, the quality of air was investigated in three different types of cars (VW Passat, VW Polo FSI, Seat Alhambra) that were all equipped with a automatic air conditioning system. Operation modes using fresh air from outside the car as well as circulating air from inside the car were examined. The total number of microorganisms and the number of mold spores were measured by impaction in a high flow air sampler. Particles of 0.5 to 5.0 microm diameter were counted by a laser particle counter device. Overall 32 occasions of sampling were performed. The concentration of microorganisms outside the cars was always higher than it was inside the cars. Few minutes after starting the air conditioning system the total number of microorganisms was reduced by 81.7%, the number of mold spores was reduced by 83.3%, and the number of particles was reduced by 87.8%. There were no significant differences neither between the types of cars nor between the types of operation mode of the air conditioning system (fresh air vs. circulating air). All parameters that were looked for in this study improved during utilization of the car's air conditioning system. We believe that the risk of an allergic reaction will be reduced during use also. Nevertheless, we recommend regular maintenance of the system and replacement of older filters after defined changing intervals.

The microbiological quality of air improves when using air conditioning systems in cars

PubMed Central

2010-01-01

Background Because of better comfort, air conditioning systems are a common feature in automobiles these days. However, its impact on the number of particles and microorganisms inside the vehicle - and by this its impact on the risk of an allergic reaction - is yet unknown. Methods Over a time period of 30 months, the quality of air was investigated in three different types of cars (VW Passat, VW Polo FSI, Seat Alhambra) that were all equipped with a automatic air conditioning system. Operation modes using fresh air from outside the car as well as circulating air from inside the car were examined. The total number of microorganisms and the number of mold spores were measured by impaction in a high flow air sampler. Particles of 0.5 to 5.0 μm diameter were counted by a laser particle counter device. Results Overall 32 occasions of sampling were performed. The concentration of microorganisms outside the cars was always higher than it was inside the cars. Few minutes after starting the air conditioning system the total number of microorganisms was reduced by 81.7%, the number of mold spores was reduced by 83.3%, and the number of particles was reduced by 87.8%. There were no significant differences neither between the types of cars nor between the types of operation mode of the air conditioning system (fresh air vs. circulating air). All parameters that were looked for in this study improved during utilization of the car's air conditioning system. Conclusions We believe that the risk of an allergic reaction will be reduced during use also. Nevertheless, we recommend regular maintenance of the system and replacement of older filters after defined changing intervals. PMID:20515449

21 CFR 866.6020 - Immunomagnetic circulating cancer cell selection and enumeration system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Immunomagnetic circulating cancer cell selection... Associated Antigen immunological Test Systems § 866.6020 Immunomagnetic circulating cancer cell selection and enumeration system. (a) Identification. An immunomagnetic circulating cancer cell selection and enumeration...

21 CFR 866.6020 - Immunomagnetic circulating cancer cell selection and enumeration system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Immunomagnetic circulating cancer cell selection... Associated Antigen immunological Test Systems § 866.6020 Immunomagnetic circulating cancer cell selection and enumeration system. (a) Identification. An immunomagnetic circulating cancer cell selection and enumeration...

21 CFR 866.6020 - Immunomagnetic circulating cancer cell selection and enumeration system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Immunomagnetic circulating cancer cell selection... Associated Antigen immunological Test Systems § 866.6020 Immunomagnetic circulating cancer cell selection and enumeration system. (a) Identification. An immunomagnetic circulating cancer cell selection and enumeration...

21 CFR 866.6020 - Immunomagnetic circulating cancer cell selection and enumeration system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Immunomagnetic circulating cancer cell selection... Associated Antigen immunological Test Systems § 866.6020 Immunomagnetic circulating cancer cell selection and enumeration system. (a) Identification. An immunomagnetic circulating cancer cell selection and enumeration...

21 CFR 866.6020 - Immunomagnetic circulating cancer cell selection and enumeration system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Immunomagnetic circulating cancer cell selection... Associated Antigen immunological Test Systems § 866.6020 Immunomagnetic circulating cancer cell selection and enumeration system. (a) Identification. An immunomagnetic circulating cancer cell selection and enumeration...

Satellite Laser Ranging in the 1990s: Report of the 1994 Belmont Workshop

NASA Technical Reports Server (NTRS)

Degnan, John J. (Editor)

1994-01-01

An international network of 43 stations in 30 countries routinely collects satellite ranging data which is used to study the solid Earth and its interactions with the oceans, atmosphere, and Moon. Data products include centimeter accuracy site positions on a global scale, tectonic plate motions, regional crustal deformation, long wavelength gravity field and geoid, polar motion, and variations in the Earth's spin rate. By calibrating and providing precise orbits for spaceborne microwave altimeters, satellite laser ranging also enables global measurement of sea and ice surface topography, mean sea level, global ocean circulation, and short wavelength gravity fields and marine geoids. It provides tests of general relativity and a means or subnanosecond time transfer. This workshop was convened to define future roles and directions in satellite laser ranging.

SpaceX Dragon Air Circulation System

NASA Technical Reports Server (NTRS)

Hernandez, Brenda; Piatrovich, Siarhei; Prina, Mauro

2011-01-01

The Dragon capsule is a reusable vehicle being developed by Space Exploration Technologies (SpaceX) that will provide commercial cargo transportation to the International Space Station (ISS). Dragon is designed to be a habitable module while it is berthed to ISS. As such, the Dragon Environmental Control System (ECS) consists of pressure control and pressure equalization, air sampling, fire detection, illumination, and an air circulation system. The air circulation system prevents pockets of stagnant air in Dragon that can be hazardous to the ISS crew. In addition, through the inter-module duct, the air circulation system provides fresh air from ISS into Dragon. To utilize the maximum volume of Dragon for cargo packaging, the Dragon ECS air circulation system is designed around cargo rack optimization. At the same time, the air circulation system is designed to meet the National Aeronautics Space Administration (NASA) inter-module and intra-module ventilation requirements and acoustic requirements. A flight like configuration of the Dragon capsule including the air circulation system was recently assembled for testing to assess the design for inter-module and intra-module ventilation and acoustics. The testing included the Dragon capsule, and flight configuration in the pressure section with cargo racks, lockers, all of the air circulation components, and acoustic treatment. The air circulation test was also used to verify the Computational Fluid Dynamics (CFD) model of the Dragon capsule. The CFD model included the same Dragon internal geometry that was assembled for the test. This paper will describe the Dragon air circulation system design which has been verified by testing the system and with CFD analysis.

Autonomous Manoeuvring Systems for Collision Avoidance on Single Carriageway Roads

PubMed Central

Jiménez, Felipe; Naranjo, José Eugenio; Gómez, Óscar

2012-01-01

The accurate perception of the surroundings of a vehicle has been the subject of study of numerous automotive researchers for many years. Although several projects in this area have been successfully completed, very few prototypes have actually been industrialized and installed in mass produced cars. This indicates that these research efforts must continue in order to improve the present systems. Moreover, the trend to include communication systems in vehicles extends the potential of these perception systems transmitting their information via wireless to other vehicles that may be affected by the surveyed environment. In this paper we present a forward collision warning system based on a laser scanner that is able to detect several potential danger situations. Decision algorithms try to determine the most convenient manoeuvre when evaluating the obstacles’ positions and speeds, road geometry, etc. Once detected, the presented system can act on the actuators of the ego-vehicle as well as transmit this information to other vehicles circulating in the same area using vehicle-to-vehicle communications. The system has been tested for overtaking manoeuvres under different scenarios and the correct actions have been performed. PMID:23443391

Autonomous manoeuvring systems for collision avoidance on single carriageway roads.

PubMed

Jiménez, Felipe; Naranjo, José Eugenio; Gómez, Oscar

2012-11-29

The accurate perception of the surroundings of a vehicle has been the subject of study of numerous automotive researchers for many years. Although several projects in this area have been successfully completed, very few prototypes have actually been industrialized and installed in mass produced cars. This indicates that these research efforts must continue in order to improve the present systems. Moreover, the trend to include communication systems in vehicles extends the potential of these perception systems transmitting their information via wireless to other vehicles that may be affected by the surveyed environment. In this paper we present a forward collision warning system based on a laser scanner that is able to detect several potential danger situations. Decision algorithms try to determine the most convenient manoeuvre when evaluating the obstacles' positions and speeds, road geometry, etc. Once detected, the presented system can act on the actuators of the ego-vehicle as well as transmit this information to other vehicles circulating in the same area using vehicle-to-vehicle communications. The system has been tested for overtaking manoeuvres under different scenarios and the correct actions have been performed.

In-situ laser fenestration of endovascular stent-graft in abdominal aortic aneurysm repair (EVAR)

NASA Astrophysics Data System (ADS)

Micheletti, Filippo; Pini, Roberto; Piazza, Roberta; Ferrari, Vincenzo; Condino, Sara; Rossi, Francesca

2017-02-01

Endovascular abdominal aortic aneurysms repair (EVAR) involves the minimally invasive implantation of a stent-graft within the aorta to exclude the aneurysm from the circulation thus preventing its rupture. The feasibility of such operation is highly dependent on the aorta morphology and in general the presence of one/both renal arteries emerging from the aneurysm is the absolute limit for the implantation of a standard stent-graft. Consequently, classical intervention methods involve the implantation of a custom-made graft with fenestrations, leading to extremely complicated surgeries with high risks for the patient and high costs. Recent techniques introduced the use of standard grafts (i.e. without fenestrations) in association with mechanical in-situ fenestration, but this procedure is limited principally by the brittleness and low stability of the environment, in addition to the difficulty of controlling the guidance of the endovascular tools due to the temporarily block of the blood flow. In this work we propose an innovative EVAR strategy, which involves in-situ fenestration with a fiber guided laser tool, controlled via an electromagnetic navigation system. The fiber is sensorized to be tracked by means of the driving system and, using a 3D model of the patient anatomy, the surgeon can drive the fiber to the aneurysm, where the stent has been previously released, to realize the proper fenestration(s). The design and construction of the catheter laser tool will be presented, togheter with preliminary fenestration tests on graft-materials, including the effects due to the presence of blood and tissues.

Broadband terahertz generation of metamaterials

DOEpatents

Luo, Liang; Wang, Jigang; Koschny, Thomas; Wegener, Martin; Soukoulis, Costas M.

2017-06-20

Provided are systems and methods to generate single-cycle THz pulses from a few tens of nanometers thin layer of split ring resonators (SRRs) via optical rectification of femtosecond laser pulses. The emitted THz radiation, with a spectrum ranging from about 0.1 to 4 THz, arises exclusively from pumping the magnetic-dipole resonance of SRRs around 200 THz. This resonant enhancement, together with pump polarization dependence and power scaling of the THz emission, underpins the nonlinearity from optically induced circulating currents in SRRs, with a huge effective nonlinear susceptibility of 0.8.times.10.sup.-16 m.sup.2/V that far exceeds surface nonlinearities of both thin films and bulk organic/inorganic crystals and sheet nonlinearities of non-centrosymmetric materials such as ZnTe.

Circulation Systems on Microcomputers.

ERIC Educational Resources Information Center

Carlson, Gary

1984-01-01

Reports on the use of microcomputers in comprehensive library circulation systems. Topics covered include system requirements (reliability, completeness); determining circulation system needs (saving money, improving service, modernization); limitations of microcomputers (capacity, kinds of data stored, number of stations or terminals); system…

The effects of conventional extracorporeal circulation versus miniaturized extracorporeal circulation on microcirculation during cardiopulmonary bypass-assisted coronary artery bypass graft surgery

PubMed Central

Yuruk, Koray; Bezemer, Rick; Euser, Mariska; Milstein, Dan M.J.; de Geus, Hilde H.R.; Scholten, Evert W.; de Mol, Bas A.J.M.; Ince, Can

2012-01-01

OBJECTIVES To reduce the complications associated with cardiopulmonary bypass (CPB) during cardiac surgery, many modifications have been made to conventional extracorporeal circulation systems. This trend has led to the development of miniaturized extracorporeal circulation systems. Cardiac surgery using conventional extracorporeal circulation systems has been associated with significantly reduced microcirculatory perfusion, but it remains unknown whether this could be prevented by an mECC system. Here, we aimed to test the hypothesis that microcirculatory perfusion decreases with the use of a conventional extracorporeal circulation system and would be preserved with the use of an miniaturized extracorporeal circulation system. METHODS Microcirculatory density and perfusion were assessed using sublingual side stream dark-field imaging in patients undergoing on-pump coronary artery bypass graft (CABG) surgery before, during and after the use of either a conventional extracorporeal circulation system (n = 10) or a miniaturized extracorporeal circulation system (n = 10). In addition, plasma neutrophil gelatinase-associated lipocalin and creatinine levels and creatinine clearance were assessed up to 5 days post-surgery to monitor renal function. RESULTS At the end of the CPB, one patient in the miniaturized extracorporeal circulation-treated group and five patients in the conventional extracorporeal circulation-treated group received one bag of packed red blood cells (300 ml). During the CPB, the haematocrit and haemoglobin levels were slightly higher in the miniaturized extracorporeal circulation-treated patients compared with the conventional extracorporeal circulation-treated patients (27.7 ± 3.3 vs 24.7 ± 2.0%; P = 0.03; and 6.42 ± 0.75 vs 5.41 ± 0.64 mmol/l; P < 0.01). The density of perfused vessels with a diameter <25 µm (i.e. perfused vessel density) decreased slightly in the conventional extracorporeal circulation-treated group from 16.4 ± 3.8 to 12.8 ± 3.3 mm/mm2 (P < 0.01) and remained stable in the miniaturized extracorporeal circulation-treated group (16.3 ± 2.7 and 15.2 ± 2.9 mm/mm2 before and during the pump, respectively). Plasma neutrophil gelatinase-associated lipocalin levels were increased following the use of extracorporeal circulation in both groups, and no differences were observed between the groups. Plasma creatinine levels and creatinine clearance were not affected by CABG surgery or CPB. CONCLUSIONS The results from this relatively small study suggest that the use of the miniaturized extracorporeal circulation system is associated with a statistically significant (but clinically insignificant) reduction in haemodilution and microcirculatory hypoperfusion compared with the use of the conventional extracorporeal circulation system. PMID:22700685

Detection, isolation, and capture of circulating breast cancer cells with photoacoustic flow cytometry

NASA Astrophysics Data System (ADS)

Bhattacharyya, Kiran; Njoroge, Martin; Goldschmidt, Benjamin S.; Gaffigan, Brian; Rood, Kyle; Viator, John A.

2013-03-01

According to the CDC, breast cancer is the most common cancer and the second leading cause of cancer related deaths among women. Metastasis, or the presence of secondary tumors caused by the spread of cancer cells via the circulatory or lymphatic systems, significantly worsens the prognosis of any breast cancer patient. In this study, a technique is developed to detect circulating breast cancer cells in human blood using a photoacoustic flow cytometry method. A Q-switched laser with a 5 ns pulse at 532 nm is used to interrogate thousands of cells with one pulse as they flow through the beam path. Cells which are pigmented, either naturally or artificially, emit an ultrasound wave as a result of the photoacoustic (PA) effect. Breast cancer cells are targeted with chromophores through immunochemistry in order to provide pigment. After which, the device is calibrated to demonstrate a single-cell detection limit. Cultured breast cancer cells are added to whole blood to reach a biologically relevant concentration of about 25-45 breast cancer cells per 1 mL of blood. An in vitro photoacoustic flow cytometer is used to detect and isolate these cells followed by capture with the use of a micromanipulator. This method can not only be used to determine the disease state of the patient and the response to therapy, it can also be used for genetic testing and in vitro drug trials since the circulating cell can be captured and studied.

An approach enabling adaptive FEC for OFDM in fiber-VLLC system

NASA Astrophysics Data System (ADS)

Wei, Yiran; He, Jing; Deng, Rui; Shi, Jin; Chen, Shenghai; Chen, Lin

2017-12-01

In this paper, we propose an orthogonal circulant matrix transform (OCT)-based adaptive frame-level-forward error correction (FEC) scheme for fiber-visible laser light communication (VLLC) system and experimentally demonstrate by Reed-Solomon (RS) Code. In this method, no extra bits are spent for adaptive message, except training sequence (TS), which is simultaneously used for synchronization and channel estimation. Therefore, RS-coding can be adaptively performed frames by frames via the last received codeword-error-rate (CER) feedback estimated by the TSs of the previous few OFDM frames. In addition, the experimental results exhibit that over 20 km standard single-mode fiber (SSMF) and 8 m visible light transmission, the costs of RS codewords are at most 14.12% lower than those of conventional adaptive subcarrier-RS-code based 16-QAM OFDM at bit error rate (BER) of 10-5.

Athermal laser treatment of the diabetic leg

NASA Astrophysics Data System (ADS)

Ignat, P.; Suteanu, S.; Brojbeanu, Gabriela; Vasiliu, Virgil V.

1995-03-01

This work shows the result obtained in the medical clinic of the `Dr. I. Cantacuzino Hospital' on a lot of 43 diabetic patients using the `LASSIS' devices composed of a He-Ne laser and 4 semiconductor lasers. The 43 patients showed various clinic pictures of a diabetic leg (diabetic arteriopathy and neuropathy) 16 of the lot showed an arteriopathy with claudication and a decrease of pulses oscillometrically measurements, 15 had ulceration and a beginning of gangrene and the other 12 showed a plantary boring ill. There has been achieved an amelioration of the oscillometric index of the claudication while walking the amelioration of local circulation, together with the limitation of the necrosis. For the boring ill, there has been achieved the acceleration of the granulating and epithelization process avoiding surgeries, suppuration and cutaneous plasties. The response to the laser treatment was compared to the response to the classic treatment (vasodilatation surgery unstrapping, antibiotherapy) on a proving lot. We appreciated that the cicatrization and local vasodilatation with athermal laser treatment should be a hope for the treatment of patients suffering of diabetic arteriopathy and neuropathy.

Cavity-enhanced Raman spectroscopy with optical feedback cw diode lasers for gas phase analysis and spectroscopy.

PubMed

Salter, Robert; Chu, Johnny; Hippler, Michael

2012-10-21

A variant of cavity-enhanced Raman spectroscopy (CERS) is introduced, in which diode laser radiation at 635 nm is coupled into an external linear optical cavity composed of two highly reflective mirrors. Using optical feedback stabilisation, build-up of circulating laser power by 3 orders of magnitude occurs. Strong Raman signals are collected in forward scattering geometry. Gas phase CERS spectra of H(2), air, CH(4) and benzene are recorded to demonstrate the potential for analytical applications and fundamental molecular studies. Noise equivalent limits of detection in the ppm by volume range (1 bar sample) can be achieved with excellent linearity with a 10 mW excitation laser, with sensitivity increasing with laser power and integration time. The apparatus can be operated with battery powered components and can thus be very compact and portable. Possible applications include safety monitoring of hydrogen gas levels, isotope tracer studies (e.g., (14)N/(15)N ratios), observing isotopomers of hydrogen (e.g., radioactive tritium), and simultaneous multi-component gas analysis. CERS has the potential to become a standard method for sensitive gas phase Raman spectroscopy.

Cu(II)-Doped Polydopamine-Coated Gold Nanorods for Tumor Theranostics.

PubMed

Liu, Shuwei; Wang, Lu; Lin, Min; Wang, Dandan; Song, Ziqi; Li, Shuyao; Ge, Rui; Zhang, Xue; Liu, Yi; Li, Zhimin; Sun, Hongchen; Yang, Bai; Zhang, Hao

2017-12-27

Gold nanorods (AuNRs) are potentially useful in tumor theranostics, but the poor stability, high toxicity, and rapid removal by the immune system seriously limit their theranostic applications. In our study, we demonstrate the fabrication of Cu(II)-doped polydopamine-coated AuNR (AuNR@CuPDA), which significantly improves the potentials in tumor theranostics. Besides the improvement of physiological stability and biocompatibility, the PDA shell increases the photothermal performance and prolongs the blood circulation time of AuNRs. The half-life of AuNRs during blood circulation increases from 0.7 to 4.5 h after PDA coating, and the injected dose per gram of tumor tissue is 4.6% ID g -1 for AuNR@CuPDA. In addition to computer tomography imaging, the loading of Cu(II) in PDA shell endows AuNR@CuPDA with magnetic resonance imaging function. Cu(II) doped in PDA shell also exhibits chemotherapeutic behavior, and the tumor inhibitor rate is 31.2%. Further combining 808 nm laser-driven photothermal therapy, tumors were completely ablated, and no recurrence was observed. Liver and renal functions tests and histological analysis of major organs confirm that AuNR@CuPDA is in good safety.

The application of laser Doppler velocimetry to trailing vortex definition and alleviation

NASA Technical Reports Server (NTRS)

Orloff, K. L.; Grant, G. R.

1973-01-01

A laser Doppler velocimeter whose focal volume can be rapidly traversed through a flowfield has been used to overcome the problem introduced by excursions of the central vortex filament within a wind tunnel test section. The basic concepts of operation of the instrument are reviewed and data are presented which accurately define the trailing vortex from a square-tipped rectangular wing. Measured axial and tangential velocity distributions are given, both with and without a vortex dissipator panel installed at the wing tip. From the experimental data, circulation and vorticity distributions are obtained and the effect of turbulence injection into the vortex structure is discussed.

A Selective Stratistical Study of Transaction Activity in a Large On-Line Automated Circulation System. Final Report.

ERIC Educational Resources Information Center

Guthrie, Gerry D.

The objective of this study was to provide the library community with basic statistical data from on-line activity in the Ohio State University Libraries' Circulation System. Over 1.6 million archive records in the circulation system for 1972 were investigated to produce subject reports of circulation activity, activity reports by collection…

Precise Orbit Determination Of Low Earth Satellites At AIUB Using GPS And SLR Data

NASA Astrophysics Data System (ADS)

Jaggi, A.; Bock, H.; Thaller, D.; Sosnica, K.; Meyer, U.; Baumann, C.; Dach, R.

2013-12-01

An ever increasing number of low Earth orbiting (LEO) satellites is, or will be, equipped with retro-reflectors for Satellite Laser Ranging (SLR) and on-board receivers to collect observations from Global Navigation Satellite Systems (GNSS) such as the Global Positioning System (GPS) and the Russian GLONASS and the European Galileo systems in the future. At the Astronomical Institute of the University of Bern (AIUB) LEO precise orbit determination (POD) using either GPS or SLR data is performed for a wide range of applications for satellites at different altitudes. For this purpose the classical numerical integration techniques, as also used for dynamic orbit determination of satellites at high altitudes, are extended by pseudo-stochastic orbit modeling techniques to efficiently cope with potential force model deficiencies for satellites at low altitudes. Accuracies of better than 2 cm may be achieved by pseudo-stochastic orbit modeling for satellites at very low altitudes such as for the GPS-based POD of the Gravity field and steady-state Ocean Circulation Explorer (GOCE).

In vitro microfluidic circulatory system for circulating cancer cells

PubMed Central

wan, jiandi; Fan, Rong; Emery, Travis; Zhang, Yongguo; Xia, Yuxuan; Sun, Jun; Wan, Jiandi

2016-01-01

Circulating tumor cells (CTCs) experience hemodynamic shear stress in circulation and play critical roles in cancer metastasis. The effect of shear on CTCs, however, remains less studied. Here, we described a protocol to circulate HCT116 human colon cancer cells in a microfluidic circulatory system mimicking physiologically relevant circulating conditions. This protocol represents a useful scaffold to mimic the transportation of CTCs in circulation and thus provides an effective means to study the effect of shear on CTCs. We anticipate that future studies using the developed system will help us to further investigate the regulatory roles of shear in molecular responses of CTCs. PMID:28690779

Reactivation of a Tin-Oxide-Containing Catalyst

NASA Technical Reports Server (NTRS)

Hess, Robert; Sidney, Barry; Schryer, David; Miller, Irvin; Miller, George; Upchurch, Bill; Davis, Patricia; Brown, Kenneth

2010-01-01

The electrons in electric-discharge CO2 lasers cause dissociation of some CO2 into O2 and CO, and attach themselves to electronegative molecules such as O2, forming negative O2 ions, as well as larger negative ion clusters by collisions with CO or other molecules. The decrease in CO2 concentration due to dissociation into CO and O2 will reduce the average repetitively pulsed or continuous wave laser power, even if no disruptive negative ion instabilities occur. Accordingly, it is the primary object of this invention to extend the lifetime of a catalyst used to combine the CO and O2 products formed in a laser discharge. A promising low-temperature catalyst for combining CO and O2 is platinum on tin oxide (Pt/SnO2). First, the catalyst is pretreated by a standard procedure. The pretreatment is considered complete when no measurable quantity of CO2 is given off by the catalyst. After this standard pretreatment, the catalyst is ready for its low-temperature use in the sealed, high-energy, pulsed CO2 laser. However, after about 3,000 minutes of operation, the activity of the catalyst begins to slowly diminish. When the catalyst experiences diminished activity during exposure to the circulating gas stream inside or external to the laser, the heated zone surrounding the catalyst is raised to a temperature between 100 and 400 C. A temperature of 225 C was experimentally found to provide an adequate temperature for reactivation. During this period, the catalyst is still exposed to the circulating gas inside or external to the laser. This constant heating and exposing the catalyst to the laser gas mixture is maintained for an hour. After heating and exposing for an appropriate amount of time, the heated zone around the catalyst is allowed to return to the nominal operating temperature of the CO2 laser. This temperature normally resides in the range of 23 to 100 C. Catalyst activity can be measured as the percentage conversion of CO to CO2. In the specific embodiment described above, the initial steady-state conversion percentage was 70 percent. After four days, this conversion percentage decreased to 67 percent. No decrease in activity is acceptable because the catalyst must maintain its activity for long periods of time. After being subjected to the reactivation process of the present invention, the conversion percentage rose to 77 percent. Such a reactivation not only returned the catalyst to its initial steady state but resulted in a 10-percent improvement over the initial steady state value.

Environmental stability of actively mode locked fibre lasers

NASA Astrophysics Data System (ADS)

Hill, Calum H.; Lee, Stephen T.; Reid, Derryck T.; Baili, Ghaya; Davies, John

2016-10-01

Lasers developed for defence related applications typically encounter issues with reliability and meeting desired specification when taken from the lab to the product line. In particular the harsh environmental conditions a laser has to endure can lead to difficulties. This paper examines a specific class of laser, namely actively mode-locked fibre lasers (AMLFLs), and discusses the impact of environmental perturbations. Theoretical and experimental results have assisted in developing techniques to improve the stability of a mode-locked pulse train for continuous operation. Many of the lessons learned in this research are applicable to a much broader category of lasers. The AMLFL consists of a fibre ring cavity containing a semiconductor optical amplifier (SOA), an isolator, an output coupler, a circulator, a bandpass filter and a modulator. The laser produces a train of 6-ps pulses at 800 nm with a repetition rate in the GHz regime and a low-noise profile. This performance is realisable in a laboratory environment. However, even small changes in temperature on the order of 0.1 °C can cause a collapse of mode-locked dynamics such that the required stability cannot be achieved without suitable feedback. Investigations into the root causes of this failure were performed by changing the temperature of components that constitute the laser resonator and observing their properties. Several different feedback mechanisms have been investigated to improve laser stability in an environment with dynamic temperature changes. Active cavity length control will be discussed along with DC bias control of the Mach-Zehnder modulator (MZM).

Bucknell On-Line Circulation System; A Library Staff View.

ERIC Educational Resources Information Center

Rivoire, Helena

The Bucknell On-Line Circulation System (BLOCS) was designed to meet the requirements of a circulation system of the Ellen Clarke Bertrand Library of Bucknell University. The requirements for an automated system were, in sum: (1) a system whose operations were not only reliable but simple enough for student assistants (many of whom work only 10…

In vivo wide-field multispectral scanning laser ophthalmoscopy–optical coherence tomography mouse retinal imager: longitudinal imaging of ganglion cells, microglia, and Müller glia, and mapping of the mouse retinal and choroidal vasculature

PubMed Central

Zhang, Pengfei; Zam, Azhar; Jian, Yifan; Wang, Xinlei; Li, Yuanpei; Lam, Kit S.; Burns, Marie E.; Sarunic, Marinko V.; Pugh, Edward N.; Zawadzki, Robert J.

2015-01-01

Abstract. Scanning laser ophthalmoscopy (SLO) and optical coherence tomography (OCT) provide complementary views of the retina, with the former collecting fluorescence data with good lateral but relatively low-axial resolution, and the latter collecting label-free backscattering data with comparable lateral but much higher axial resolution. To take maximal advantage of the information of both modalities in mouse retinal imaging, we have constructed a compact, four-channel, wide-field (∼50  deg) system that simultaneously acquires and automatically coregisters three channels of confocal SLO and Fourier domain OCT data. The scanner control system allows “zoomed” imaging of a region of interest identified in a wide-field image, providing efficient digital sampling and localization of cellular resolution features in longitudinal imaging of individual mice. The SLO is equipped with a “flip-in” spectrometer that enables spectral “fingerprinting” of fluorochromes. Segmentation of retina layers and en face display facilitate spatial comparison of OCT data with SLO fluorescence patterns. We demonstrate that the system can be used to image an individual retinal ganglion cell over many months, to simultaneously image microglia and Müller glia expressing different fluorochromes, to characterize the distinctive spatial distributions and clearance times of circulating fluorochromes with different molecular sizes, and to produce unequivocal images of the heretofore uncharacterized mouse choroidal vasculature. PMID:26677070

Role of Endocannabinoids and Cannabinoid-1 Receptors in Cerebrocortical Blood Flow Regulation

PubMed Central

Horváth, Béla; Benkő, Rita; Lacza, Zsombor; Járai, Zoltán; Sándor, Péter; Di Marzo, Vincenzo; Pacher, Pál; Benyó, Zoltán

2013-01-01

Background Endocannabinoids are among the most intensively studied lipid mediators of cardiovascular functions. In the present study the effects of decreased and increased activity of the endocannabinoid system (achieved by cannabinoid-1 (CB1) receptor blockade and inhibition of cannabinoid reuptake, respectively) on the systemic and cerebral circulation were analyzed under steady-state physiological conditions and during hypoxia and hypercapnia (H/H). Methodology/Principal Findings In anesthetized spontaneously ventilating rats the CB1-receptor antagonist/inverse agonist AM-251 (10 mg/kg, i.v.) failed to influence blood pressure (BP), cerebrocortical blood flow (CoBF, measured by laser-Doppler flowmetry) or arterial blood gas levels. In contrast, the putative cannabinoid reuptake inhibitor AM-404 (10 mg/kg, i.v.) induced triphasic responses, some of which could be blocked by AM-251. Hypertension during phase I was resistant to AM-251, whereas the concomitant CoBF-increase was attenuated. In contrast, hypotension during phase III was sensitive to AM-251, whereas the concomitant CoBF-decrease was not. Therefore, CoBF autoregulation appeared to shift towards higher BP levels after CB1-blockade. During phase II H/H developed due to respiratory depression, which could be inhibited by AM-251. Interestingly, however, the concomitant rise in CoBF remained unchanged after AM-251, indicating that CB1-blockade potentially enhanced the reactivity of the CoBF to H/H. In accordance with this hypothesis, AM-251 induced a significant enhancement of the CoBF responses during controlled stepwise H/H. Conclusion/Significance Under resting physiological conditions CB1-receptor mediated mechanisms appear to have limited influence on systemic or cerebral circulation. Enhancement of endocannabinoid levels, however, induces transient CB1-independent hypertension and sustained CB1-mediated hypotension. Furthermore, enhanced endocannabinoid activity results in respiratory depression in a CB1-dependent manner. Finally, our data indicate for the first time the involvement of the endocannabinoid system and CB1-receptors in the regulation of the cerebral circulation during H/H and also raise the possibility of their contribution to the autoregulation of CoBF. PMID:23308211

[The present and future state of minimized extracorporeal circulation].

PubMed

Meng, Fan; Yang, Ming

2013-05-01

Minimized extracorporeal circulation improved in the postoperative side effects of conventional extracorporeal circulation is a kind of new extracorporeal circulation. This paper introduces the principle, characteristics, applications and related research of minimized extracorporeal circulation. For the problems of systemic inflammatory response syndrome and limited assist time, the article proposes three development direction including system miniaturization and integration, pulsatile blood pump and the adaptive control by human parameter identification.

Superconductor rotor cooling system

DOEpatents

Gamble, Bruce B.; Sidi-Yekhlef, Ahmed; Schwall, Robert E.; Driscoll, David I.; Shoykhet, Boris A.

2004-11-02

A system for cooling a superconductor device includes a cryocooler located in a stationary reference frame and a closed circulation system external to the cryocooler. The closed circulation system interfaces the stationary reference frame with a rotating reference frame in which the superconductor device is located. A method of cooling a superconductor device includes locating a cryocooler in a stationary reference frame, and transferring heat from a superconductor device located in a rotating reference frame to the cryocooler through a closed circulation system external to the cryocooler. The closed circulation system interfaces the stationary reference frame with the rotating reference frame.

Superconductor rotor cooling system

DOEpatents

Gamble, Bruce B.; Sidi-Yekhlef, Ahmed; Schwall, Robert E.; Driscoll, David I.; Shoykhet, Boris A.

2002-01-01

A system for cooling a superconductor device includes a cryocooler located in a stationary reference frame and a closed circulation system external to the cryocooler. The closed circulation system interfaces the stationary reference frame with a rotating reference frame in which the superconductor device is located. A method of cooling a superconductor device includes locating a cryocooler in a stationary reference frame, and transferring heat from a superconductor device located in a rotating reference frame to the cryocooler through a closed circulation system external to the cryocooler. The closed circulation system interfaces the stationary reference frame with the rotating reference frame.

RhoA-stimulated intra-capillary morphology switch facilitates the arrest of individual circulating tumor cells.

PubMed

Huang, Xi; Yang, Yu; Zhao, Yuwei; Cao, Dan; Ai, Xiaolin; Zeng, Anqi; Gou, Maling; Cai, Lulu; Yang, Hanshuo; Zhao, Chengjian

2018-05-15

Metastasis is the primary cause of death for most cancer patients. Hematogenous arrest of circulating tumor cells (CTCs) is an essential prerequisite for metastases formation. Using transparent transgenic zebrafish (kdrl:eGFP; Casper), together with resonant laser scanning confocal microscopy, we tracked the fate of CTCs in vivo in the blood circulation for days. We found the intra-capillary morphology-switch (ICMS) of individual CTCs from strip to sphere was necessary for their intravascular arrests. Further genetic and pharmacological inhibition experiments indicated that the RhoA signaling was necessary for ICMS and the arrest of CTCs. At last, we demonstrated that early treatment by a clinically approved RhoA/ROCK inhibitor, Fasudil, could efficiently inhibit the initial arrest of individual CTCs and reduce the incidence of tumor metastasis in both zebrafish and mouse models. These results together indicate that RhoA-stimulated ICMS represents a mechanism for the arrest of individual CTCs, providing a potential target for future treatments of hematogenous metastatic disease. © 2017 UICC.

Combination of Kinematics with Flow Visualization to Compute Total Circulation

NASA Technical Reports Server (NTRS)

Brasseur, J. G; Chang, I-Dee

1981-01-01

A method is described in which kinematics is exploited to compute the total circulation of a vortex from relatively simple flow visualization experiments. There are several advantages in the technique, including the newly acquired ability to calculate the changes in strength of a single vortex as it evolves. The main concepts and methodology are discussed in a general way for application to vortices which carry along with them definable regions of essentially irrotational fluid; however, the approach might be generalized to other flows which contain regions of concentrated vorticity. As an illustrative example, an application to the study of the transient changes in total circulation of individual vortex rings as they travel up a tube is described, taking into account the effect of the tube boundary. The accuracy of the method, assessed in part by a direct comparison with a laser Doppler measurement is felt to be well within experimental precision for vortex rings over a wide range of Reynolds numbers.

Reaction of cells to local, regional, and general low-intensive laser irradiation

NASA Astrophysics Data System (ADS)

Baibekov, Iskander M.; Kasymov, A. S.; Musaev, Erkin S.; Vorojeikin, V. M.; Artikov, S. N.

1993-07-01

Local influence of low intensive laser irradiation (LILI) of Helium-Neon (HNL), Copper vapor (CVL), Nitrogen (UVL) and Arsenic Gallium (AGL) lasers cause stimulation of processes of physiological and reparative regeneration in intact skin, and mucous membrane of stomach and duodenum, dermatome wounds and gastroduodenal ulcers. Structural bases of these effects are the acceleration of cell proliferation and differentiation and also the activation of intracellular structures and intensification of cell secretion. Regional influence of the pointed types of LILI on hepar in cirrhosis and hepatitis causes decreasing of the inflammatory and cirrhotic changes. After endo- and exo-vascular laser irradiations of blood the decreasing of the number of pathological forms of erythrocytes and the increasing of their catalase activity, are indicated. General (total) laser irradiation of the organism--laser shower, increases the bone marrow cells proliferation, especially myeloid series. It is accompanied with acceleration of their differentiation and migration in circulation. It was revealed, that HNL to a considerable extent influences the epithelial cells and CVL the connective tissue cells. UVL increases the amount of microorganisms on cell surfaces (membrane bound microorganisms). Regional irradiation of the LILI causes both direct and indirect influence of cells. Structural changes of bone marrow cells and gut mucous membrane cells indicate intersystemic interaction.

Aerodynamic Flow Field Measurements for Automotive Systems

NASA Technical Reports Server (NTRS)

Hepner, Timothy E.

1999-01-01

The design of a modern automotive air handling system is a complex task. The system is required to bring the interior of the vehicle to a comfortable level in as short a time as possible. A goal of the automotive industry is to predict the interior climate of an automobile using advanced computational fluid dynamic (CFD) methods. The development of these advanced prediction tools will enable better selection of engine and accessory components. The goal of this investigation was to predict methods used by the automotive industry. To accomplish this task three separate experiments were performed. The first was a laboratory setup where laser velocimeter (LV) flow field measurements were made in the heating and air conditioning unit of a Ford Windstar. The second involved flow field measurements in the engine compartment of a Ford Explorer, with the engine running idle. The third mapped the flow field exiting the center dashboard panel vent inside the Explorer, while the circulating fan operated at 14 volts. All three experiments utilized full-coincidence three-component LV systems. This enabled the mean and fluctuating velocities to be measured along with the Reynolds stress terms.

Development of a High-Average-Power Compton Gamma Source for Lepton Colliders

NASA Astrophysics Data System (ADS)

Pogorelsky, Igor; Polyanskiy, Mikhail N.; Yakimenko, Vitaliy; Platonenko, Viktor T.

2009-01-01

Gamma- (γ-) ray beams of high average power and peak brightness are of demand for a number of applications in high-energy physics, material processing, medicine, etc. One of such examples is gamma conversion into polarized positrons and muons that is under consideration for projected lepton colliders. A γ-source based on the Compton backscattering from the relativistic electron beam is a promising candidate for this application. Our approach to the high-repetition γ-source assumes placing the Compton interaction point inside a CO2 laser cavity. A laser pulse interacts with periodical electron bunches on each round-trip inside the laser cavity producing the corresponding train of γ-pulses. The round-trip optical losses can be compensated by amplification in the active laser medium. The major challenge for this approach is in maintaining stable amplification rate for a picosecond CO2-laser pulse during multiple resonator round-trips without significant deterioration of its temporal and transverse profiles. Addressing this task, we elaborated on a computer code that allows identifying the directions and priorities in the development of such a multi-pass picosecond CO2 laser. Proof-of-principle experiments help to verify the model and show the viability of the concept. In these tests we demonstrated extended trains of picosecond CO2 laser pulses circulating inside the cavity that incorporates the Compton interaction point.

Long axial imaging range using conventional swept source lasers in optical coherence tomography via re-circulation loops

NASA Astrophysics Data System (ADS)

Bradu, Adrian; Jackson, David A.; Podoleanu, Adrian

2018-03-01

Typically, swept source optical coherence tomography (SS-OCT) imaging instruments are capable of a longer axial range than their camera based (CB) counterpart. However, there are still various applications that would take advantage for an extended axial range. In this paper, we propose an interferometer configuration that can be used to extend the axial range of the OCT instruments equipped with conventional swept-source lasers up to a few cm. In this configuration, the two arms of the interferometer are equipped with adjustable optical path length rings. The use of semiconductor optical amplifiers in the two rings allows for compensating optical losses hence, multiple paths depth reflectivity profiles (Ascans) can be combined axially. In this way, extremely long overall axial ranges are possible. The use of the recirculation loops produces an effect equivalent to that of extending the coherence length of the swept source laser. Using this approach, the achievable axial imaging range in SS-OCT can reach values well beyond the limit imposed by the coherence length of the laser, to exceed in principle many centimeters. In the present work, we demonstrate axial ranges exceeding 4 cm using a commercial swept source laser and reaching 6 cm using an "in-house" swept source laser. When used in a conventional set-up alone, both these lasers can provide less than a few mm axial range.

46 CFR 56.50-45 - Circulating pumps.

Code of Federal Regulations, 2010 CFR

2010-10-01

... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-45 Circulating pumps. (a) A main circulating pump and emergency means for circulating water through the main condenser shall be provided. The... circulating pump and the condenser. (b) Independent sea suctions shall be provided for the main circulating...

Nanoshell-mediated targeted photothermal therapy of HER2 human breast cancer cells using pulsed and continuous wave lasers: an in vitro study.

PubMed

Khosroshahi, Mohammad E; Hassannejad, Zahra; Firouzi, Masoumeh; Arshi, Ahmad R

2015-09-01

In this study, we report the apoptosis induction in HER2 overexpressed breast cancer cells using pulsed, continuous wave lasers and polyvinylpyrrolidone (PVP)-stabilized magneto-plasmonic nanoshells (PVP-MPNS) delivered by immunoliposomes. The immunoliposomes containing PVP-MPNS were fabricated and characterized. Heating efficiency of the synthesized nanostructures was calculated. The effect of functionalization on cellular uptake of nanoparticles was assessed using two cell lines of BT-474 and Calu-6. The best uptake result was achieved by functionalized liposome (MPNS-LAb) and BT-474. Also, the interaction of 514 nm argon (Ar) and Nd/YAG second harmonic 532-nm lasers with nanoparticles was investigated based on the temperature rise of the nanoshell suspension and the release value of 5(6)-carboxyfluorescein (CF) from CF/MPNS-loaded liposomes. The temperature increase of the suspensions after ten consecutive pulses of 532 nm and 5 min of irradiation by Ar laser were measured approximately 2 and 12 °C, respectively. The irradiation of CF/MPNS-loaded liposomes by Ar laser for 3 min resulted in 24.3 % release of CF, and in the case of 532 nm laser, the release was laser energy dependent. Furthermore, the comparison of CF release showed a higher efficiency for the Ar laser than by direct heating of nanoshell suspension using circulating water. The percentage of cell apoptosis after irradiation by Ar and 532 nm lasers were 44.6 and 42.6 %, respectively. The obtained results suggest that controlling the NP-laser interaction using optical properties of nanoshells and the laser parameters can be used to develop a new cancer therapy modality via targeted nanoshell and drug delivery.

Performance of Control System Using Microcontroller for Sea Water Circulation

NASA Astrophysics Data System (ADS)

Indriani, A.; Witanto, Y.; Pratama, A. S.; Supriyadi; Hendra; Tanjung, A.

2018-02-01

Now a day control system is very important rule for any process. Control system have been used in the automatic system. Automatic system can be seen in the industrial filed, mechanical field, electrical field and etc. In industrial and mechanical field, control system are used for control of motion component such as motor, conveyor, machine, control of process made of product, control of system and soon. In electrical field, control system can met for control of electrical system as equipment or part electrical like fan, rice cooker, refrigerator, air conditioner and etc. Control system are used for control of temperature and circulation gas, air and water. Control system of temperature and circulation of water also can be used for fisher community. Control system can be create by using microcontroller, PLC and other automatic program [1][2]. In this paper we will focus on the close loop system by using microcontroller Arduino Mega to control of temperature and circulation of sea water for fisher community. Performance control system is influenced by control equipment, sensor sensitivity, test condition, environment and others. The temperature sensor is measured using the DS18S20 and the sea water clarity sensor for circulation indicator with turbidity sensor. From the test results indicated that this control system can circulate sea water and maintain the temperature and clarity of seawater in a short time.

Laser Initiated Ignition of Liquid Propellant

DTIC Science & Technology

1991-01-31

containers held in a water bath of constant temperature 70*C. A larger vessel containing approximately 2ml of propellant was also heated in each experiment and...controller. A stirrer and forced water circulation ensured that all samples were kept at the same temperature. The water wai first heated to the final 5... electrolysed samples. 3 .. .. ....... ......................... volume of 10 ....... . 5 ....... I • . ... .. . .... .. ...... .. . . .. . . ... . .61.8 2 22i

A simple method for in vivo labelling of infiltrating leukocytes in the mouse retina using indocyanine green dye.

PubMed

Sim, Dawn A; Chu, Colin J; Selvam, Senthil; Powner, Michael B; Liyanage, Sidath; Copland, David A; Keane, Pearse A; Tufail, Adnan; Egan, Catherine A; Bainbridge, James W B; Lee, Richard W; Dick, Andrew D; Fruttiger, Marcus

2015-11-01

We have developed a method to label and image myeloid cells infiltrating the mouse retina and choroid in vivo, using a single depot injection of indocyanine green dye (ICG). This was demonstrated using the following ocular models of inflammation and angiogenesis: endotoxin-induced uveitis, experimental autoimmune uveoretinitis and laser-induced choroidal neovascularization model. A near-infrared scanning ophthalmoscope was used for in vivo imaging of the eye, and flow cytometry was used on blood and spleen to assess the number and phenotype of labelled cells. ICG was administered 72 h before the induction of inflammation to ensure clearance from the systemic circulation. We found that in vivo intravenous administration failed to label any leukocytes, whereas depot injection, either intraperitoneal or subcutaneous, was successful in labelling leukocytes infiltrating into the retina. Progression of inflammation in the retina could be traced over a period of 14 days following a single depot injection of ICG. Additionally, bright-field microscopy, spectrophotometry and flow cytometric analysis suggest that the predominant population of cells stained by ICG are circulating myeloid cells. The translation of this approach into clinical practice would enable visualization of immune cells in situ. This will not only provide a greater understanding of pathogenesis, monitoring and assessment of therapy in many human ocular diseases but might also open the ability to image immunity live for neurodegenerative disorders, cardiovascular disease and systemic immune-mediated disorders. © 2015. Published by The Company of Biologists Ltd.

Monitoring global climate change using SLR data from LARES and other geodetic satellites

NASA Astrophysics Data System (ADS)

Paolozzi, Antonio; Paris, Claudio; Pavlis, Erricos C.; Sindoni, Giampiero; Ciufolini, Ignazio

2016-04-01

The Earth Orientation Parameters (EOP), i.e. the spin axis of the Earth, is influenced by the mass redistribution inside and on the surface of the Earth. On the Earth surface, global ice melting, sea level change and atmospheric circulation are the prime contributors. Recent studies have unraveled the majority of the mysteries behind the Chandler wobble, the annual motion and the secular motion of the pole. The differences from the motion of a pole for a rigid Earth is indeed due to the mass redistribution and transfer of angular momentum among the atmosphere, the oceans and solid Earth. The technique of laser ranging and the use of laser ranged satellites such as LARES along with other techniques such Very Long Baseline Interferometry (VLBI) allow to measure the EOP with accuracies at the level of ~200 μas which correspond to few millimeters at the Earth's surface, while the use of Global Navigation Satellite System (GNSS) data can reach an accuracy even below 100 μas. At these unprecedented high levels of accuracy, even tiny anomalous behavior in EOP can be observed and thus correlated to global environmental changes such as ice melting on Greenland and the polar caps, and extreme events that involve strong ocean-atmosphere coupling interactions such as the El Niño. The contribution of Satellite Laser Ranging (SLR) data such as from the LARES mission and similar satellites to this area is outlined in this paper.

Night and Day: The Opacity of Clouds Measured by the Mars Orbiter Laser Altimeter (MOLA)

NASA Technical Reports Server (NTRS)

Neumann, G. A.; Wilson, R. J.

2006-01-01

The Mars Orbiter Laser Altimeter (MOLA) [l] on the Mars Global Surveyor spacecraft ranged to clouds over the course of nearly two Mars years [2] using an active laser ranging system. While ranging to the surface, the instrument was also able to measure the product of the surface reflectivity with the two-way atmospheric transmission at 1064 nm. Furthermore, the reflectivity has now been mapped over seasonal cycles using the passive radiometric capability built into MOLA [3]. Combining these measurements, the column opacity may be inferred. MOLA uniquely provides these measurements both night and day. This study examines the pronounced nighttime opacity of the aphelion season tropical water ice clouds, and the indiscernibly low opacity of the southern polar winter clouds. The water ice clouds (Figure 1) do not themselves trigger the altimeter but have measured opacities tau > 1.5 and are temporally and spatially correlated with temperature anomalies predicted by a Mars Global Circulation Model (MGCM) that incorporates cloud radiative effects [4]. The south polar CO2 ice clouds trigger the altimeter with a very high backscatter cross-section over a thickness of 3-9 m and are vertically dispersed over several km, but their total column opacities lie well below the MOLA measurement limit of tau = 0.7. These clouds correspond to regions of supercooled atmosphere that may form either very large specularly reflecting particles [2] or very compact, dense concentrations (>5x10(exp 6)/cu m) of 100-p particles

The impact of the ocean observing system on estimates of the California current circulation spanning three decades

NASA Astrophysics Data System (ADS)

Moore, Andrew M.; Jacox, Michael G.; Crawford, William J.; Laughlin, Bruce; Edwards, Christopher A.; Fiechter, Jérôme

2017-08-01

Data assimilation is now used routinely in oceanography on both regional and global scales for computing ocean circulation estimates and for making ocean forecasts. Regional ocean observing systems are also expanding rapidly, and observations from a wide array of different platforms and sensor types are now available. Evaluation of the impact of the observing system on ocean circulation estimates (and forecasts) is therefore of considerable interest to the oceanographic community. In this paper, we quantify the impact of different observing platforms on estimates of the California Current System (CCS) spanning a three decade period (1980-2010). Specifically, we focus attention on several dynamically related aspects of the circulation (coastal upwelling, the transport of the California Current and the California Undercurrent, thermocline depth and eddy kinetic energy) which in many ways describe defining characteristics of the CCS. The circulation estimates were computed using a 4-dimensional variational (4D-Var) data assimilation system, and our analyses also focus on the impact of the different elements of the control vector (i.e. the initial conditions, surface forcing, and open boundary conditions) on the circulation. While the influence of each component of the control vector varies between different metrics of the circulation, the impact of each observing system across metrics is very robust. In addition, the mean amplitude of the circulation increments (i.e. the difference between the analysis and background) remains relatively stable throughout the three decade period despite the addition of new observing platforms whose impact is redistributed according to the relative uncertainty of observations from each platform. We also consider the impact of each observing platform on CCS circulation variability associated with low-frequency climate variability. The low-frequency nature of the dominant climate modes in this region allows us to track through time the impact of each observation on the circulation, and illustrates how observations from some platforms can influence the circulation up to a decade into the future.

Automated Circulation Systems as a Source of Secondary Information.

ERIC Educational Resources Information Center

Chapin, Giny Ziegler

This report looks at the use of public library online circulation systems for the generation of in-house secondary information--such as statistical reports and mailing lists--and also considers problems in maintaining confidentiality of patron records when using online circulation systems. Based on a survey of the literature, general information…

On-Line Circulation: University of Guelph Library. Report No. 8.

ERIC Educational Resources Information Center

Beckman, Margaret; And Others

This report describes the development, design, and evaluation of an online circulation system at the University of Guelph, Ontario. A 1976 study identified the specific problems or inadequacies of the existing circulation system and specified design requirements for a new online system. This 1978 report is divided into six parts: (1) historical…

78 FR 19606 - Energy Conservation Program for Consumer Products: Test Procedures for Residential Furnace Fans

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-02

... electrically-powered devices used in central HVAC systems for the purposes of circulating air through ductwork...- powered device used in a central HVAC system for the purpose of circulating air through ductwork. DOE... included single-phase, electrically-powered devices that circulate air through ductwork in HVAC systems...

A Low-Cost, Efficient, Machine-Assisted Manual Circulation System

ERIC Educational Resources Information Center

Stangl, Peter

1975-01-01

A circulation system uses plastic embossed user cards, an addressograph electric imprinter, a copy of the catalog card as a book card, and a pocket imprinted by the user's card and holding the book card during circulation. (LS)

Vector solitons with polarization instability and locked polarization in a fiber laser

NASA Astrophysics Data System (ADS)

Tang, Dingkang; Zhang, Jian-Guo; Liu, Yuanshan

2012-07-01

We investigate the characteristics of vector solitons with and without locked phase velocities of orthogonal polarization components in a specially-designed laser cavity which is formed by a bidirectional fiber loop together with a semiconductor saturable absorber mirror. The characteristics of the two states are compared in the temporal and spectrum domain, respectively. Both of the two states exhibit the characteristic of mode locking while the two orthogonal polarization components are not resolved. However, for the vector soliton with unlocked phase velocities, identical intensity varies after passing through a polarization beam splitter (PBS) outside the laser cavity. Contrary to the polarization rotation locked vector soliton, the intensity does not change periodically. For the polarization-locked vector soliton (PLVS), the identical pulse intensity is still obtained after passing through the PBS and can be observed on the oscilloscope screen after photodetection. A coupler instead of a circulator is integrated in the laser cavity and strong interaction on the polarization resolved spectra of the PLVS is observed. By comparing the two states, we conclude that interaction between the two orthogonal components contributes to the locked phase velocities.

Operation of a cascade air conditioning system with two-phase loop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Yinshan; Wang, Jinliang; Zhao, Futao

A method of operating a heat transfer system includes starting operation of a first heat transfer fluid vapor/compression circulation loop including a fluid pumping mechanism, a heat exchanger for rejecting thermal energy from a first heat transfer fluid, and a heat absorption side of an internal heat exchanger. A first conduit in a closed fluid circulation loop circulates the first heat transfer fluid therethrough. Operation of a second two-phase heat transfer fluid circulation loop is started after starting operation of the first heat transfer fluid circulation loop. The second heat transfer fluid circulation loop transfers heat to the first heatmore » transfer fluid circulation loop through the internal heat exchanger and includes a heat rejection side of the internal heat exchanger, a liquid pump, and a heat exchanger evaporator. A second conduit in a closed fluid circulation loop circulates a second heat transfer fluid therethrough.« less

Development of Laser Propulsion and Tracking System for Laser-Driven Micro-Airplane

NASA Astrophysics Data System (ADS)

Ishikawa, Hiroyasu; Kajiwara, Itsuro; Hoshino, Kentaro; Yabe, Takashi; Uchida, Shigeaki; Shimane, Yoshichika

2004-03-01

The purposes of this paper are to improve the control performance of the developed laser tracking system and to develop an integrated laser propulsion/tracking system for realizing a continuous flight and control of the micro-airplane. The laser propulsion is significantly effective to achieve the miniaturization and lightening of the micro-airplane. The laser-driven micro-airplane has been studied with a paper-craft airplane and YAG laser, resulting in a successful glide of the airplane. In the next stage of the laser-driven micro-airplane development, the laser tracking is expected as key technologies to achieve continuous propulsion. Furthermore, the laser propulsion system should be combined with the laser tracking system to supply continuous propulsion. Experiments are carried out to evaluate the performance of the developed laser tracking system and integrated laser propulsion/tracking system.

Future of laser biostimulation in America today: microlight 830

NASA Astrophysics Data System (ADS)

Smith, Chadwick F.; Vangsness, C. Thomas

1992-06-01

For the last two years we have been investigating the use of a 830 nanometer laser for low level laser therapy in chronic pain syndromes. This laser is of low energy and by definition is low level therapy (a laser output which does not exceed 100 milliwatts). This wave length has been carefully selected to be in the 'window' of wavelengths between 650 and 900 nanometers. At this level, the laser energy will penetrate the epidermis, the dermis and the subcutaneous layers to the deep tissue. The tissue effect of this laser energy is not thermal but rather a stimulation of micro-circulation with a secondary effect of blocking pain enzymes and activation of the synthesis of endorphin enzymes. We have experience with approximately 75 patients who have been treated with low level laser therapy. We have engaged in a double- blind study at several General Motors facilities in Michigan to determine the effectiveness of low level laser therapy in this inflammatory condition. Repetitive injuries in the work place have moved from 18% of industrial accidents in 1981 to 52% in 1989. Carpal Tunnel Syndrome is the number one economic problem in occupational medicine. It is true that 15% of the employees of American automotive plants have Carpal Tunnel Syndrome. This large number of patients have been treated in the past by standard physiotherapy treatment modalities and ultimately by surgery for failure of conservative therapy. Incidence of 'return to work activities' has been low. We intend to show that low level laser therapy may afford a positive solution to this problem not only therapeutically but prophylactically. Indications for treatment are Chronic Pain Syndrome and Carpal Tunnel Syndrome of mild to moderate degree.

System Analysis for Decay Heat Removal in Lead-Bismuth Cooled Natural Circulated Reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takaaki Sakai; Yasuhiro Enuma; Takashi Iwasaki

2002-07-01

Decay heat removal analyses for lead-bismuth cooled natural circulation reactors are described in this paper. A combined multi-dimensional plant dynamics code (MSG-COPD) has been developed to conduct the system analysis for the natural circulation reactors. For the preliminary study, transient analysis has been performed for a 100 MWe lead-bismuth-cooled reactor designed by Argonne National Laboratory (ANL). In addition, decay heat removal characteristics of a 400 MWe lead-bismuth-cooled natural circulation reactor designed by Japan Nuclear Cycle Development Institute (JNC) has been evaluated by using MSG-COPD. PRACS (Primary Reactor Auxiliary Cooling System) is prepared for the JNC's concept to get sufficient heatmore » removal capacity. During 2000 sec after the transient, the outlet temperature shows increasing tendency up to the maximum temperature of 430 Centigrade, because the buoyancy force in a primary circulation path is temporary reduced. However, the natural circulation is recovered by the PRACS system and the out let temperature decreases successfully. (authors)« less

System Analysis for Decay Heat Removal in Lead-Bismuth-Cooled Natural-Circulation Reactors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakai, Takaaki; Enuma, Yasuhiro; Iwasaki, Takashi

2004-03-15

Decay heat removal analyses for lead-bismuth-cooled natural-circulation reactors are described in this paper. A combined multidimensional plant dynamics code (MSG-COPD) has been developed to conduct the system analysis for the natural-circulation reactors. For the preliminary study, transient analysis has been performed for a 300-MW(thermal) lead-bismuth-cooled reactor designed by Argonne National Laboratory. In addition, decay heat removal characteristics of a 400-MW(electric) lead-bismuth-cooled natural-circulation reactor designed by the Japan Nuclear Cycle Development Institute (JNC) has been evaluated by using MSG-COPD. The primary reactor auxiliary cooling system (PRACS) is prepared for the JNC concept to get sufficient heat removal capacity. During 2000 smore » after the transient, the outlet temperature shows increasing tendency up to the maximum temperature of 430 deg. C because the buoyancy force in a primary circulation path is temporarily reduced. However, the natural circulation is recovered by the PRACS system, and the outlet temperature decreases successfully.« less

A blood circulation model for reference man

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leggett, R.W.; Eckerman, K.F.; Williams, L.R.

This paper describes a dynamic blood circulation model that predicts the movement and gradual dispersal of a bolus of material in the circulation after its intravascular injection into an adult human. The main purpose of the model is to improve the dosimetry of internally deposited radionuclides that decay in the circulation to a significant extent. The total blood volume is partitioned into the blood contents of 24 separate organs or tissues, right heart chambers, left heart chambers, pulmonary circulation, arterial outflow to the systemic tissues (aorta and large arteries), and venous return from the systemic tissues (large veins). As amore » compromise between physical reality and computational simplicity, the circulation of blood is viewed as a system of first-order transfers between blood pools, with the delay time depending on the mean transit time across the pool. The model allows consideration of incomplete, tissue-dependent extraction of material during passage through the circulation and return of material from tissues to plasma.« less

Evaluation of Laser Speckle Contrast Imaging for the Assessment of Oral Mucosal Blood Flow following Periodontal Plastic Surgery: An Exploratory Study

PubMed Central

Molnár, Eszter; Molnár, Bálint; Lohinai, Zsolt; Tóth, Zsuzsanna; Benyó, Zoltán; Hricisák, Laszló; Windisch, Péter

2017-01-01

The laser speckle contrast imaging (LSCI) is proved to be a reliable tool in flap monitoring in general surgery; however, it has not been evaluated in oral surgery yet. We applied the LSCI to compare the effect of a xenogeneic collagen matrix (Geistlich Mucograft®) to connective tissue grafts (CTG) on the microcirculation of the modified coronally advanced tunnel technique (MCAT) for gingival recession coverage. Gingival microcirculation and wound fluid were measured before and after surgery for six months at twenty-seven treated teeth. In males, the flap microcirculation was restored within 3 days for both grafts followed by a hyperemic response. During the first 8 days the blood flow was higher at xenogeneic graft comparing to the CTG. In females, the ischemic period lasted for 7–12 days depending on the graft and no hyperemic response was observed. Females had more intense and prolonged wound fluid production. The LSCI method is suitable to capture the microcirculatory effect of the surgical intervention in human oral mucosa. The application of xenogeneic collagen matrices as a CTG substitute does not seem to restrain the recovery of graft bed circulation. Gender may have an effect on postoperative circulation and inflammation. PMID:28232940

Evaluation of Laser Speckle Contrast Imaging for the Assessment of Oral Mucosal Blood Flow following Periodontal Plastic Surgery: An Exploratory Study.

PubMed

Molnár, Eszter; Molnár, Bálint; Lohinai, Zsolt; Tóth, Zsuzsanna; Benyó, Zoltán; Hricisák, Laszló; Windisch, Péter; Vág, János

2017-01-01

The laser speckle contrast imaging (LSCI) is proved to be a reliable tool in flap monitoring in general surgery; however, it has not been evaluated in oral surgery yet. We applied the LSCI to compare the effect of a xenogeneic collagen matrix (Geistlich Mucograft®) to connective tissue grafts (CTG) on the microcirculation of the modified coronally advanced tunnel technique (MCAT) for gingival recession coverage. Gingival microcirculation and wound fluid were measured before and after surgery for six months at twenty-seven treated teeth. In males, the flap microcirculation was restored within 3 days for both grafts followed by a hyperemic response. During the first 8 days the blood flow was higher at xenogeneic graft comparing to the CTG. In females, the ischemic period lasted for 7-12 days depending on the graft and no hyperemic response was observed. Females had more intense and prolonged wound fluid production. The LSCI method is suitable to capture the microcirculatory effect of the surgical intervention in human oral mucosa. The application of xenogeneic collagen matrices as a CTG substitute does not seem to restrain the recovery of graft bed circulation. Gender may have an effect on postoperative circulation and inflammation.

A spectroscopic tool for identifying sources of origin for materials of military interest

NASA Astrophysics Data System (ADS)

Miziolek, Andrzej W.; De Lucia, Frank C.

2014-05-01

There is a need to identify the source of origin for many items of military interest, including ammunition and weapons that may be circulated and traded in illicit markets. Both fieldable systems (man-portable or handheld) as well as benchtop systems in field and home base laboratories are desired for screening and attribution purposes. Laser Induced Breakdown Spectroscopy (LIBS) continues to show significant capability as a promising new tool for materials identification, matching, and provenance. With the use of the broadband, high resolution spectrometer systems, the LIBS devices can not only determine the elemental inventory of the sample, but they are also capable of elemental fingerprinting to signify sources of origin of various materials. We present the results of an initial study to differentiate and match spent cartridges from different manufacturers and countries. We have found that using Partial Least Squares Discriminant Analysis (PLS-DA) we are able to achieve on average 93.3% True Positives and 5.3% False Positives. These results add to the large body of publications that have demonstrated that LIBS is a particularly suitable tool for source of origin determinations.

Laser and solar-photovoltaic space power systems comparison. II.

NASA Technical Reports Server (NTRS)

De Young, R. J.; Stripling, J.; Enderson, T. M.; Humes, D. H.; Davis, W. T.

1984-01-01

A comparison of total system cost is made between solar photovoltaic and laser/receiver systems. The laser systems assume either a solar-pumped CO2 blackbody transfer laser with MHD receiver or a solar pumped liquid neodymium laser with a photovoltaic receiver. Total system costs are less for the laser systems below 300 km where drag is significant. System costs are highly dependent on altitude.

A compact Nd:YAG DPSSL using diamond-cooled technology

NASA Astrophysics Data System (ADS)

Chou, Hsian P.; Wang, Yu-Lin; Hasson, Victor H.; Trainor, Daniel W.

2005-03-01

In our diamond-cooled approach, thin disks of laser gain material, e.g., Nd:YAG, are alternated between thin disks of single crystal synthetic diamond whose heat conductivity is over 2000 W/m-°K. The gain medium is face-pumped (along the optical axis) by the output of laser diode arrays. This optical configuration produces heat transfer from Nd:YAG to the diamond, in the direction of the optical axis, and then heat is rapidly conducted radially outward through the diamond to the cooling fluid circulating at the circumference of the diamond/YAG assembly. This geometry effectively removes the heat from the gain material in a manner that permits the attainment of high power output with excellent beam quality.

High pumping-power fiber combiner for double-cladding fiber lasers and amplifiers

NASA Astrophysics Data System (ADS)

Zheng, Jinkun; Zhao, Wei; Zhao, Baoyin; Li, Zhe; Chang, Chang; Li, Gang; Gao, Qi; Ju, Pei; Gao, Wei; She, Shengfei; Wu, Peng; Hou, Chaoqi; Li, Weinan

2018-03-01

A high pumping-power fiber combiner for backward pumping configurations is fabricated and demonstrated by manufacturing process refinement. The pump power handling capability of every pump fiber can extend to 600 W, corresponding to the average pump coupling efficiency of 94.83%. Totally, 2.67-kW output power with the beam quality factor M2 of 1.41 was obtained, using this combiner in the fiber amplifier experimental setup. In addition, the temperature of the splicing region was less than 50.0°C in the designed combiner under the action of circulating cooling water. The experimental results prove that the designed combiner is a promising integrated all-fiber device for multikilowatt continuous-wave fiber laser with excellent beam quality.

Solar-pumped laser for free space power transmission

NASA Technical Reports Server (NTRS)

Lee, Ja H.

1989-01-01

Laser power transmission; laser systems; space-borne and available lasers; 2-D and 1 MW laser diode array systems; technical issues; iodine solar pumped laser system; and laser power transmission applications are presented. This presentation is represented by viewgraphs only.

Proceedings of the 2004 NASA/ONR Circulation Control Workshop, Part 1

NASA Technical Reports Server (NTRS)

Jones, Gregory S. (Editor); Joslin, Ronald D. (Editor)

2005-01-01

As technological advances influence the efficiency and effectiveness of aerodynamic and hydrodynamic applications, designs and operations, this workshop was intended to address the technologies, systems, challenges and successes specific to Coanda driven circulation control in aerodynamics and hydrodynamics. A major goal of this workshop was to determine the 2004 state-of-the-art in circulation control and understand the roadblocks to its application. The workshop addressed applications, CFD, and experiments related to circulation control, emphasizing fundamental physics, systems analysis, and applied research. The workshop consisted of 34 single session oral presentations and written papers that focused on Naval hydrodynamic vehicles (e.g. submarines), Fixed Wing Aviation, V/STOL platforms, propulsion systems (including wind turbine systems), ground vehicles (automotive and trucks) and miscellaneous applications (e.g., poultry exhaust systems and vacuum systems). Several advanced CFD codes were benchmarked using a two-dimensional NCCR circulation control airfoil. The CFD efforts highlighted inconsistencies in turbulence modeling, separation and performance predictions.

Slip stream apparatus and method for treating water in a circulating water system

DOEpatents

Cleveland, J.R.

1997-03-18

An apparatus is described for treating water in a circulating water system that has a cooling water basin which includes a slip stream conduit in flow communication with the circulating water system, a source of acid solution in flow communication with the slip stream conduit, and a decarbonator in flow communication with the slip stream conduit and the cooling water basin. In use, a slip stream of circulating water is drawn from the circulating water system into the slip stream conduit of the apparatus. The slip stream pH is lowered by contact with an acid solution provided from the source thereof. The slip stream is then passed through a decarbonator to form a treated slip stream, and the treated slip stream is returned to the cooling water basin. 4 figs.

Public Library Automation Report: Circulation [and] Appendix.

ERIC Educational Resources Information Center

Gotanda, Masae; And Others

An online circulation system--ULISYS (the Universal Library System Ltd.) manufactured by Digital Equipment Corporation (DEC)--is being installed in the Hawaii State Library, Kaneohe Regional Library, Kailua Community Library and Waimanalo Community/School Library. These libraries are the first users of a statewide online circulation system…

Task five report: Laser communications for data acquisition networks. [characteristics of lasers and laser systems for optical communication applications

NASA Technical Reports Server (NTRS)

1973-01-01

Laser communication technology and laser communication performance are reviewed. The subjects discussed are: (1) characteristics of laser communication systems, (2) laser technology problems, (3) means of overcoming laser technology problems, and (4) potential schedule for including laser communications into data acquisition networks. Various types of laser communication systems are described and their capabilities are defined.

Empirical justification of the elementary model of money circulation

NASA Astrophysics Data System (ADS)

Schinckus, Christophe; Altukhov, Yurii A.; Pokrovskii, Vladimir N.

2018-03-01

This paper proposes an elementary model describing the money circulation for a system, composed by a production system, the government, a central bank, commercial banks and their customers. A set of equations for the system determines the main features of interaction between the production and the money circulation. It is shown, that the money system can evolve independently of the evolution of production. The model can be applied to any national economy but we will illustrate our claim in the context of the Russian monetary system.

ALMDS laser system

NASA Astrophysics Data System (ADS)

Kushina, Mark E.; Heberle, Geoff; Hope, Michael; Hall, David; Bethel, Michael; Calmes, Lonnie K.

2003-06-01

The ALMDS (Airborne Laser Mine Detection System) has been developed utilizing a solid-state laser operating at 532nm for naval mine detection. The laser system is integrated into a pod that mounts externally on a helicopter. This laser, along with other receiver systems, enables detailed underwater bathymetry. CEO designs and manufactures the laser portion of this system. Arete Associates integrates the laser system into the complete LIDAR package that utilizes sophisticated streak tube detection technology. Northrop Grumman is responsible for final pod integration. The laser sub-system is comprised of two separate parts: the LTU (Laser Transmitter Unit) and the LEU (Laser Electronics Unit). The LTU and LEU are undergoing MIL-STD-810 testing for vibration, shock, temperature storage and operation extremes, as well as MIL-STD-704E electrical power testing and MIL-STD-461E EMI testing. The Nd:YAG MOPA laser operates at 350 Hz pulse repetition frequency at 45 Watts average 532nm power and is controlled at the system level from within the helicopter. Power monitor circuits allow real time laser health monitoring, which enables input parameter adjustments for consistent laser behavior.

Applications of SLR

NASA Technical Reports Server (NTRS)

Schutz, Bob E.

1993-01-01

Satellite Laser Ranging (SLR) has a rich history of development which began in the 1960s with 10 meter-level first generation systems. These systems evolved with order of magnitude improvements to the systems that now produce several millimeter single shot range precisions. What began, in part, as an interesting application of the new laser technology has become an essential component of modern, precision space geodesy, which in turn enables contributions to a variety of science areas. Modern space geodesy is the beneficiary of technological developments which have enabled precision geodetic measurements. Aside from SLR and its closely related technique, Lunar Laser Ranging (LLR), Very Long Baseline Interferometry (VLBI) has made prominent science contributions also. In recent years, the Global Positioning System (GPS) has demonstrated a rapidly growing popularity as the result of demonstrated low cost with high precision instrumentation. Other modern techniques such as DORIS have demonstrated the ability to make significant science contributions; furthermore, PRARE can be expected to contribute in its own right. An appropriate question is 'why should several techniques be financially supported'? While there are several answers, I offer the opinion that, in consideration of the broad science areas that are the benefactors of space geodesy, no single technique can meet all the requirements and/or expectations of the science areas in which space geodesy contributes or has the potential for contributing. The more well-known science areas include plate tectonics, earthquake processes, Earth rotation/orientation, gravity (static and temporal), ocean circulation, land, and ice topography, to name a few applications. It is unfortunate that the modern space geodesy techniques are often viewed as competitive, but this view is usually encouraged by funding competition, especially in an era of growing needs but diminishing budgets. The techniques are, for the most part, complementary and the ability to reduce the data to geodetic parameters from several techniques promotes confidence in the geophysical interpretations. In the following sections, the current SLR applications are reviewed in the context of the other techniques. The strengths and limitations of SLR are reviewed and speculation about the future prospects are offered.

Spectral and Radiometric Calibration Using Tunable Lasers

NASA Technical Reports Server (NTRS)

McCorkel, Joel (Inventor)

2017-01-01

A tunable laser system includes a tunable laser, an adjustable laser cavity for producing one or more modes of laser light emitted from the tunable laser, a first optical parametric oscillator positioned in a light path of the adjustable laser cavity, and a controller operable to simultaneously control parameters of at least the tunable laser, the first optical parametric oscillator, and the adjustable laser cavity to produce a range of wavelengths emitted from the tunable laser system. A method of operating a tunable laser system includes using a controller to simultaneously control parameters of a tunable laser, an adjustable laser cavity for producing one or more modes of laser light emitted from the tunable laser, and a first optical parametric oscillator positioned in a light path of the adjustable laser cavity, to produce a range of wavelengths emitted from the tunable laser system.

Absolute wind measurements in the lower thermosphere of Venus using infrared heterodyne spectroscopy

NASA Technical Reports Server (NTRS)

Goldstein, Jeffrey J.

1990-01-01

The first absolute wind velocities above the Venusian cloud-tops were obtained using NASA/Goddard infrared heterodyne spectrometers at the NASA Infrared Telescope Facility (IRTF) and the McMath Solar Telescope. Beam-integrated Doppler displacements in the non-thermal emission core of (12)C(16)O2 10.33 micron R(8) sampled the line of sight projection of the lower thermospheric wind field (100 to 120 km). A field-usable Lamb-dip laser stabilization system, developed for spectrometer absolute frequency calibration to less than + or - 0.1 MHz, allowed S/N-limited line of sight velocity resolution at the 1 m/s level. The spectrometer's diffraction-limited beam (1.7 arc-second HPBW at McMath, 0.9 arc-second HPBW at IRTF), and 1 to 2 arc-second seeing, provided the spatial resolution necessary for circulation model discrimination. Qualitative analysis of beam-integrated winds provided definitive evidence of a dominant subsolar-antisolar circulation in the lower thermosphere. Beam-integrated winds were modelled with a 100x100 grid over the beam, incorporating beam spatial rolloff and across-the-beam gradients in non-thermal emission intensity, line of sight projection geometry, and horizontal wind velocity. Horizontal wind velocity was derived from a 2-parameter model wind field comprised of subsolar-antisolar and zonal components. Best-fit models indicated a dominant subsolar-antisolar flow with 120 m/s cross-terminator winds and a retrograde zonal component with a 25 m/s equatorial velocity. A review of all dynamical indicators above the cloud-tops allowed development of an integrated and self-consistent picture of circulation in the 70 to 200 km range.

Pulverized Tejon Lookout Granite: Attempts at Placing Constraints on the Processes

NASA Astrophysics Data System (ADS)

Sisk, M.; Dor, O.; Rockwell, T.; Girty, G.; Ben-Zion, Y.

2007-12-01

We have described and analyzed pulverized Tejon Lookout granite recovered from several transects of the western segment of the Garlock fault on Tejon Ranch in southern California. Observations and data collected at this location are compared to a sampled transect of the San Andreas fault at Tejon Pass previously studied by Wilson et al. (2005), also exposing the Tejon Lookout granite. The purpose of this study is to characterize the physical and chemical properties of the pervasively pulverized leucocratic rocks at multiple locations and to hopefully place constraints on the processes producing them. To accomplish this we performed particle size analysis with the use of both laser particle analyzer and pipette methodology; major and trace chemistry analyses determined by XRF; clay mineralogy determined by XRD; and we evaluated fabric and texture through the study of thin sections. Recovered samples met the field criteria of pulverization developed by Dor et al., 2006 - that is, the individual 1-2 mm-sized crystals can be recognized in the field but the granite (including quartz and feldspar) can be mashed with ones fingers and exhibits the texture of toothpaste. All samples were analyzed on a Horiba LA930 Laser Particle Analyzer in an attempt to reproduce the earlier results of Wilson et al. (2005) with similar methodology. We also utilized the classic pipette methodology to ensure complete discrimination of particle sizes. Our PSD analysis shows that the dominant particle size falls in the 31-125 micron range, much coarser than previously reported by Wilson et al. (2005), with >90% of the total sample falling in the >31 micron size range. We can reproduce the previously documented results by allowing the samples to circulate for long periods of time at slow circulation speeds in the laser particle size analyzer, during which time the coarse fraction settles out, thereby leaving only the fine fraction for detection. However, subsequent increase in the circulation speed leads to a complete recovery of the original PSD. Our XRF and XRD analyses provide evidence of the lack of major weathering products and their inability to skew the PSD results in a significant way. Dor et al. (2007) and Stillings et al. (2007) document evidence that support theoretical predictions and previous inferences of pulverization occurring in the upper few kilometers, especially along faults of the southern San Andreas system. Geophysical observations of Lewis et al. (2005, 2007) provide evidence that low velocity fault- parallel layers, which are likely made of pulverized or highly damaged material, are dominant in the upper few kilometers of the crust. Their asymmetric position with respect to the slipping zone, in agreement with asymmetric patterns of small scale mapped rock damage (Dor et al., 2006), suggest that pulverized rocks are likely the product of a preferred rupture direction during dynamic slip. Our results combined with the above mentioned works imply that pulverized fault zone rocks at multiple locations are much less damaged than suggested in previous studies.

Circulation Control Model Experimental Database for CFD Validation

NASA Technical Reports Server (NTRS)

Paschal, Keith B.; Neuhart, Danny H.; Beeler, George B.; Allan, Brian G.

2012-01-01

A 2D circulation control wing was tested in the Basic Aerodynamic Research Tunnel at the NASA Langley Research Center. A traditional circulation control wing employs tangential blowing along the span over a trailing-edge Coanda surface for the purpose of lift augmentation. This model has been tested extensively at the Georgia Tech Research Institute for the purpose of performance documentation at various blowing rates. The current study seeks to expand on the previous work by documenting additional flow-field data needed for validation of computational fluid dynamics. Two jet momentum coefficients were tested during this entry: 0.047 and 0.114. Boundary-layer transition was investigated and turbulent boundary layers were established on both the upper and lower surfaces of the model. Chordwise and spanwise pressure measurements were made, and tunnel sidewall pressure footprints were documented. Laser Doppler Velocimetry measurements were made on both the upper and lower surface of the model at two chordwise locations (x/c = 0.8 and 0.9) to document the state of the boundary layers near the spanwise blowing slot.

Laser blood irradiation effect on electrophysiological characteristics of acute coronary syndrome patients

NASA Astrophysics Data System (ADS)

Khotiaintsev, Sergei N.; Doger-Guerrero, E.; Glebova, L.; Svirid, V.; Sirenko, Yuri

1996-11-01

This paper treats electro-physiological effects of the low- level laser irradiation of blood (LBI). The data presented here are based on the observation of almost 200 patients suffering from the acute disruption of coronary blood circulation, unstable angina pectoris and myocardial infarction. Statistically significant changes of the electro-physiological characteristics were observed in the group of 65 patients, treated by the LBI. In particular, the significant 6 percent extension of the effective refractory period was observed. The electrical situation threshold has increased by 20.6 percent. The significant changes of some other important electro-physiological characteristics were within the range of 5-15 percent. In this paper, the data obtained on the LBI effectiveness are compared also with the results obtained on 94 patients who in addition to the standard anti-angina therapy were treated by the autohaemo- transfusion performed simultaneously with the UV-light irradiation of the transfused blood. The results obtained demonstrate the significant positive effect of the low energy LBI. The electrophysiological data obtained have good correlation with observed anti-arrhythmic effect of the LBI. This is proved by the data obtained on the electro- physiological characteristics of the cardiovascular system and by other clinical data on the experimental and control group of patients. In the course of this research the exact effect of the low level LBI was established. LBI led to the pronounced positive changes in electro-physiological characteristics of the cardiovascular system of the patients, it also led to the pronounced anti-arrhythmic effect.

The choice: Welding with CO2 or Nd:YAG lasers

NASA Astrophysics Data System (ADS)

Leong, Keng H.

The recent commercial availability of multi-kilowatt Nd:YAG lasers has opened new avenues for rapid laser processing as well as intensified the competition (cost effectiveness) between CO2 and Nd:YAG laser systems. Vendors offering Nd:YAG laser systems may claim lower operating costs (than CO2) and fiberoptic beam delivery flexibility while CO2 systems vendors may emphasize lower capital cost and well established processing requirements and experience. The capital and operating costs of a laser system are impacted by demand and supply economics and technological advances. Frequently the total cost of a workcell using a laser for processing has to be considered rather than the laser system alone. Consequently it is not very practical to approach the selection of a laser system based on its capital cost and estimated operating cost only. This presentation describes a more pragmatic approach to aid the user in the selection of the optimal multi-kilowatt laser system for a particular processing requirement with emphasis on welding. CO2 laser systems are well established on the factory floor. Consequently, emphasis is given to the comparative application of Nd:YAG lasers, process requirements and performance. Requirements for the laser welding of different metals are examined in the context of hardware (laser system and beam delivery) selection and examples of welding speeds that can be achieved using CO2 and Nd:YAG lasers are examined.

Slip stream apparatus and method for treating water in a circulating water system

DOEpatents

Cleveland, Joe R.

1997-01-01

An apparatus (10) for treating water in a circulating water system (12) t has a cooling water basin (14) includes a slip stream conduit (16) in flow communication with the circulating water system (12), a source (36) of acid solution in flow communication with the slip stream conduit (16), and a decarbonator (58) in flow communication with the slip stream conduit (16) and the cooling water basin (14). In use, a slip stream of circulating water is drawn from the circulating water system (12) into the slip stream conduit (16) of the apparatus (10). The slip stream pH is lowered by contact with an acid solution provided from the source (36) thereof. The slip stream is then passed through a decarbonator (58) to form a treated slip stream, and the treated slip stream is returned to the cooling water basin (14).

Upgrades at the Duke Free Electron Laser Laboratory

NASA Astrophysics Data System (ADS)

Howell, Calvin R.

2004-11-01

Major upgrades to the storage-ring based photon sources at the Duke Free Electron Laser Laboratory (DFELL) are underway. The photon sources at the DFELL are well suited for research in the areas of medicine, biophysics, accelerator physics, nuclear physics and material science. These upgrades, which will be completed by the summer 2006, will significantly enhance the capabilities of the ultraviolet (UV) free-electron laser (FEL) and the high intensity gamma-ray source (HIGS). The HIGS is a relatively new research facility at the DFELL that is operated jointly by the DFELL and the Triangle Universities Nuclear Laboratory. The gamma-ray beam is produced by Compton back scattering of the UV photons inside the FEL optical cavity off the circulating electrons in the storage ring. The gamma-ray beam is 100% polarized and its energy resolution is selected by collimation. The capabilities of the upgraded facility will be described, the status of the upgrades will be summarized, and the proposed first-generation research program at HIGS will be presented.

Research on the liquid coolant applied in the high repetition rate slab amplifier

NASA Astrophysics Data System (ADS)

Wang, Bingyan; Li, Yangshuai; Zhang, Panzheng; Wang, Li; Zhang, Yanli; Feng, Tao; Zhou, Qiong; Liu, Qiang; Li, Haiyuan; Zhang, Xu; Zhou, Shenlei; Ma, Weixin; Zhu, Jian; Zhu, Jianqiang

2018-03-01

High repetition rate slab amplifier (HRRSA) is extraordinarily indispensable for the future fusion power plant, ultra-short laser, laser weapon, and so on. Thermal controlling is the decisive factor for the repetition rate and the output energy of the slab amplifier. For larger clear aperture HRRSA, flash-lamp pumped slab amplifier based on neodymium phosphate glass (Nd:glass) is chosen with the liquid cooling. The liquid coolant circulates across the Nd:glass and takes off the thermal induced in the pumping process. A novel liquid coolant (Series A) whose refractive index is the same with Nd:glass is proposed to alleviate the wavefront distortion induced by thermal. The chemical stability of the liquid coolant under high energy flash-lamp irradiation with 200 shots and under the irradiation of a 1053nm laser with 19 hours and 37 hours are experimented. The results show that the chemical stability of the liquid coolant is stable under irradiation.

Compton backscattered collimated x-ray source

DOEpatents

Ruth, R.D.; Huang, Z.

1998-10-20

A high-intensity, inexpensive and collimated x-ray source is disclosed for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications. 4 figs.

Compton backscattered collimated x-ray source

DOEpatents

Ruth, Ronald D.; Huang, Zhirong

1998-01-01

A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

Compton backscattered collmated X-ray source

DOEpatents

Ruth, Ronald D.; Huang, Zhirong

2000-01-01

A high-intensity, inexpensive and collimated x-ray source for applications such as x-ray lithography is disclosed. An intense pulse from a high power laser, stored in a high-finesse resonator, repetitively collides nearly head-on with and Compton backscatters off a bunched electron beam, having relatively low energy and circulating in a compact storage ring. Both the laser and the electron beams are tightly focused and matched at the interaction region inside the optical resonator. The laser-electron interaction not only gives rise to x-rays at the desired wavelength, but also cools and stabilizes the electrons against intrabeam scattering and Coulomb repulsion with each other in the storage ring. This cooling provides a compact, intense bunch of electrons suitable for many applications. In particular, a sufficient amount of x-rays can be generated by this device to make it an excellent and flexible Compton backscattered x-ray (CBX) source for high throughput x-ray lithography and many other applications.

All-optical gain-clamped wideband serial EDFA with ring-shaped laser

NASA Astrophysics Data System (ADS)

Lu, Yung-Hsin; Chi, Sien

2004-01-01

We experimentally investigate the static and dynamic properties of all-optical gain-clamped wideband (1530-1600 nm) serial erbium-doped fiber amplifier with a single ring-shaped laser, which consists of a circulator and a fiber Bragg grating at the output end. The lasing light passing through the second stage is intentionally blocked at the output end by a C/L-band wavelength division multiplexer owning the huge insertion loss, and thus, the copropagating ring-laser light is formed by the first stage. This design can simultaneously clamp the gains of 1547 and 1584 nm probes near 14 dB and shows the same dynamic range of input power up to -4 dBm for conventional band and long-wavelength band. Furthermore, the transient responses of 1551 and 1596 nm surviving channels exhibit small power excursions (<0.54 dB) as the total saturating tone with -2 dBm is modulated on and off at 270 Hz.

Comparison of electrically driven lasers for space power transmission

NASA Technical Reports Server (NTRS)

Deyoung, R. J.; Lee, J. H.; Williams, M. D.; Schuster, G.; Conway, E. J.

1988-01-01

High-power lasers in space could provide power for a variety of future missions such as spacecraft electric power requirements and laser propulsion. This study investigates four electrically pumped laser systems, all scaled to 1-MW laser output, that could provide power to spacecraft. The four laser systems are krypton fluoride, copper vapor, laser diode array, and carbon dioxide. Each system was powered by a large solar photovoltaic array which, in turn, provided power for the appropriate laser power conditioning subsystem. Each system was block-diagrammed, and the power and efficiency were found for each subsystem block component. The copper vapor system had the lowest system efficiency (6 percent). The CO2 laser was found to be the most readily scalable but has the disadvantage of long laser wavelength.

Method and system for modulation of gain suppression in high average power laser systems

DOEpatents

Bayramian, Andrew James [Manteca, CA

2012-07-31

A high average power laser system with modulated gain suppression includes an input aperture associated with a first laser beam extraction path and an output aperture associated with the first laser beam extraction path. The system also includes a pinhole creation laser having an optical output directed along a pinhole creation path and an absorbing material positioned along both the first laser beam extraction path and the pinhole creation path. The system further includes a mechanism operable to translate the absorbing material in a direction crossing the first laser beam extraction laser path and a controller operable to modulate the second laser beam.

Comparison of circulation times of thermal waters discharging from the Idaho batholith based on geothermometer temperatures, helium concentrations, and 14C measurements

USGS Publications Warehouse

Mariner, R.H.; Evans, William C.; Young, H.W.

2006-01-01

Circulation times of waters in geothermal systems are poorly known. In this study, we examine the thermal waters of the Idaho batholith to verify whether maximum system temperatures, helium concentrations, and 14C values are related to water age in these low-to-moderate temperature geothermal systems. He/N2 values of gas collected from thermal waters that circulate solely through distinct units of the Idaho batholith correlate linearly with Na-K-(4/3)Ca geothermometer temperatures, showing that both variables are excellent indicators of relative water age. Thermal waters that circulate in early Tertiary (45-50 Ma) granite of the Sawtooth batholith have 3.5 times more helium than thermal waters of the same aquifer temperature that circulate through the main Cretaceous granite (average 91 Ma). Hot spring waters circulating in hydrothermally altered parts of the batholith have very little dissolved helium and no correlation between He/N2 values and geothermometer temperatures. Thermal waters discharging from the Idaho batholith are more depleted in deuterium than modern precipitation in the area. Recharge to these geothermal systems occurred from at least 10,000 BP for the cooler systems up to about 33,000 BP for the hotter systems.

High throughput solar cell ablation system

DOEpatents

Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

2014-10-14

A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

High throughput solar cell ablation system

DOEpatents

Harley, Gabriel; Pass, Thomas; Cousins, Peter John; Viatella, John

2012-09-11

A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

Zebrafish as an early stage screening tool to study the systemic circulation of nanoparticulate drug delivery systems in vivo.

PubMed

Sieber, Sandro; Grossen, Philip; Detampel, Pascal; Siegfried, Salome; Witzigmann, Dominik; Huwyler, Jörg

2017-10-28

Nanomedicines have gained much attention for the delivery of small molecules or nucleic acids as treatment options for many diseases. However, the transfer from experimental systems to in vivo applications remains a challenge since it is difficult to assess their circulation behavior in the body at an early stage of drug discovery. Thus, innovative and improved concepts are urgently needed to overcome this issue and to close the gap between empiric nanoparticle design, in vitro assessment, and first in vivo experiments using rodent animal models. This study was focused on the zebrafish as a vertebrate screening model to assess the circulation in blood and extravasation behavior of nanoparticulate drug delivery systems in vivo. To validate this novel approach, monodisperse preparations of fluorescently labeled liposomes with similar size and zeta potential were injected into transgenic zebrafish lines expressing green fluorescent protein in their vasculature. Phosphatidylcholine-based lipids differed by fatty acid chain length and saturation. Circulation behavior and vascular distribution pattern were evaluated qualitatively and semi-quantitatively using image analysis. Liposomes composed of lipids with lower transition temperature (<28°C) as well as PEGylated liposomes showed longer circulation times and extravasation. In contrast, liposomes composed of lipids with transition temperatures>28°C bound to venous parts of the vasculature. This circulation patterns in the zebrafish model did correlate with published and experimental pharmacokinetic data from mice and rats. Our findings indicate that the zebrafish model is a useful vertebrate screening tool for nanoparticulate drug delivery systems to predict their in vivo circulation behavior with respect to systemic circulation time and exposure. Copyright © 2017 Elsevier B.V. All rights reserved.

Repetitive output laser system and method using target reflectivity

DOEpatents

Johnson, Roy R.

1978-01-01

An improved laser system and method for implosion of a thermonuclear fuel pellet in which that portion of a laser pulse reflected by the target pellet is utilized in the laser system to initiate a succeeding target implosion, and in which the energy stored in the laser system to amplify the initial laser pulse, but not completely absorbed thereby, is used to amplify succeeding laser pulses initiated by target reflection.

The study of laser beam riding guided system based on 980nm diode laser

NASA Astrophysics Data System (ADS)

Qu, Zhou; Xu, Haifeng; Sui, Xin; Yang, Kun

2015-10-01

With the development of science and technology, precision-strike weapons has been considered to be important for winning victory in military field. Laser guidance is a major method to execute precision-strike in modern warfare. At present, the problems of primary stage of Laser guidance has been solved with endeavors of countries. Several technical aspects of laser-beam riding guided system have been mature, such as atmosphere penetration of laser beam, clutter inhibition on ground, laser irradiator, encoding and decoding of laser beam. Further, laser beam quality, equal output power and atmospheric transmission properties are qualified for warfare situation. Riding guidance instrument is a crucial element of Laser-beam riding guided system, and is also a vital element of airborne, vehicle-mounted and individual weapon. The optical system mainly consist of sighting module and laser-beam guided module. Photoelectric detector is the most important sensing device of seeker, and also the key to acquire the coordinate information of target space. Currently, in consideration of the 1.06 u m of wavelength applied in all the semi-active laser guided weapons systems, lithium drifting silicon photodiode which is sensitive to 1.06 u m of wavelength is used in photoelectric detector. Compared to Solid and gas laser, diode laser has many merits such as small volume, simple construction, light weight, long life, low lost and easy modulation. This article introduced the composition and operating principle of Laser-beam riding guided system based on 980 nm diode laser, and made a analysis of key technology; for instance, laser irradiator, modulating disk of component, laser zooming system. Through the use of laser diode, Laser-beam riding guided system is likely to have smaller shape and very light.

An elementary model of money circulation

NASA Astrophysics Data System (ADS)

Pokrovskii, Vladimir N.; Schinckus, Christophe

2016-12-01

This paper investigates money circulation for a system, consisting of a production system, the government, a central bank, commercial banks and many customers of the commercial banks. A set of equations for the system is written; the theory determines the main features of interaction between production and money circulation. Investigation of the equations in a steady-state situation reveals some relationship among output of the production system and monetary variables. The relation of quantity theory of money is confirmed, whereas a new concept of the efficiency of the system is introduced.

Thermoresponsive hyaluronic acid nanogels as hydrophobic drug carrier to macrophages.

PubMed

Fernandes Stefanello, Talitha; Szarpak-Jankowska, Anna; Appaix, Florence; Louage, Benoit; Hamard, Lauriane; De Geest, Bruno G; van der Sanden, Boudewijn; Nakamura, Celso Vataru; Auzély-Velty, Rachel

2014-11-01

Delivery systems for macrophages are particularly attractive since these phagocytic cells play a important role in immunological and inflammatory responses, also acting as host cells for microorganisms that are involved in deadly infectious diseases, such as leishmaniasis. Hyaluronic acid (HA) is specifically recognized by macrophages that are known to express HA receptors. Therefore, in this study, we focused on HA-based nanogels as drug carriers for these cells. The drug delivery was validated in an in vivo study on mice using intravital two-photon laser scanning microscopy. HA derivatives were modified with a biocompatible oligo(ethylene glycol)-based thermoresponsive polymer to form nanogels. These HA conjugates were readily prepared by varying the molar mass of initial HA and the degree of substitution via radical-mediated thiol-ene chemistry in aqueous solution. The derivatives were shown to self-assemble into spherical gel particles with diameters ranging from 150 to 214 nm above 37 °C. A poorly water-soluble two-photon dye was successfully loaded into the nanogels during this self-assembly process. In vitro cellular uptake tests using a RAW 264.7 murine macrophage cell line showed successful intracellular delivery of the hydrophobic dye. After intravenous injection in mice, the nanogels circulated freely in the blood but were rapidly phagocytized within 13 min by circulating macrophages and stored in the liver and spleen, as observed by two-photon microscopy. Benefit can be thus expected in using such a delivery system for the liver and spleen macrophage-associated diseases. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Fibrin monomer increases platelet adherence to tumor cells in a flowing system: a possible role in metastasis?

PubMed

Biggerstaff, J P; Seth, N B; Meyer, T V; Amirkhosravi, A; Francis, J L

1998-12-15

Considerable evidence exists linking hemostasis and malignancy. Platelet adhesion to tumor cells has been implicated in the metastatic process. Plasma fibrinogen (Fg) and fibrin (Fn) monomer, increased in cancer, may play a role in tumor biology. Binding of Fn monomer to tumor cells and its effect on platelet-tumor cell adhesion in a flowing system were studied. Fn monomer was produced by adding thrombin (1 micro/mL) to FXIII- and plasminogen-free Fg in the presence of Gly-Pro-Arg-Pro (GPRP) amide. Fn monomer binding to live A375 cells was visualized by confocal laser scanning microscopy (CLSM). Adherent cells were perfused for 1h with Fn monomer, washed and stained in situ with anti-human Fn (American Biogenetic Sciences, Inc.) followed by goat anti-mouse IgG(FITC). Platelet adherence to Fn monomer treated A375 cells was performed under flow conditions by passing platelets (5x10(4)/microl 0.25 mL/min; labeled with the carbocyanine dye DiI) over the tumor cells for 30 min. CLSM images were obtained after washing. There was considerable binding of Fn monomer, but not Fg alone. Platelets adhered relatively weakly to untreated A375 cells and this was not significantly affected by pre-treatment of the tumor cells with fibrinogen or thrombin. However, pre-treatment with Fn monomer resulted in extensive platelet binding to tumor cells, suggesting that coagulation activation and the subsequent increase in circulating Fn monomer may enhance platelet adhesion to circulating tumor cells and thereby facilitate metastatic spread.

Heterodyne laser diagnostic system

DOEpatents

Globig, Michael A.; Johnson, Michael A.; Wyeth, Richard W.

1990-01-01

The heterodyne laser diagnostic system includes, in one embodiment, an average power pulsed laser optical spectrum analyzer for determining the average power of the pulsed laser. In another embodiment, the system includes a pulsed laser instantaneous optical frequency measurement for determining the instantaneous optical frequency of the pulsed laser.

Research on the laser angle deception jamming technology of laser countermeasure

NASA Astrophysics Data System (ADS)

Ma, Shi-wei; Chen, Wen-jian; Gao, Wei; Duan, Yuan-yuan

2015-10-01

In recent years , laser guided weapons behave very well at destroying the military goals in the local wars, the single-shot probability, effective range and hitting precision getting better. And the semi-active laser guided weapons are the most widely used laser guided weapons. In order to improve the viability and protect important military goals, it's necessary to study the technology to against the semi-active guided weapons. This paper studies the working principle, the advantages and disadvantages of the semi-active guided weapons at first, and analyze the possibility of laser angle deception jamming system working. Then it analyzes the working principle and process of laser angle deception jamming technology. Finally it designs a half-real simulation system of laser angle deception jamming, which consists of semi-active laser guided weapons simulation system and laser angle deception jamming system. The simulation system demonstrates the working process of the laser angle deception jamming system. This paper provides fundamental base for the research on the countermeasure technology of semi-active laser guided weapons.

Three-Photon Luminescence of Gold Nanorods Excited by 1040 nm Femtosecond Laser for High Contrast Tissue and In Vivo Imaging

NASA Astrophysics Data System (ADS)

Wang, Shaowei; Zhao, Xinyuan; Zhang, Hequn; Cai, Fuhong; Qian, Jun

2016-01-01

Gold Nanorods (GNRs) with tunable aspect ratios can strongly absorb and scatter light in the NIR region due to their localized surface plasmon resonance (LSPR) property, and have been demonstrated to exhibit strong plasmon enhanced multiphoton luminescence (MPL) with brightness many times stronger than the conventional organic chromophores. In this study, we synthesized GNRs with longitudinal LSPR peak at 1036 nm to match our home-built light source 1040 nm femtosecond laser, which locates in the “optical window” where the tissue absorbs relatively little light. PEGylated GNRs with great biocompatibility were intravenously injected through the tail vein into mice. Excited by 1040 nm laser, the GNRs exhibit bright three-photon luminescence (3PL) signals while circulating in the blood vessels. The use of GNRs as bright contrast agents for 3PL imaging of mouse ear blood vessels in vivo was demonstrated. And GNRs targeted in tissues can be excited by 1040 nm laser and could be clearly visualized with no autofluorescence background. These results indicated that 3PL of GNRs is very promising for deep in vivo bioimaging and assessing the distribution of GNRs in tissues with high contrast.

300 mW of coherent light at 488 nm using a generic approach

NASA Astrophysics Data System (ADS)

Karamehmedović, Emir; Pedersen, Christian; Andersen, Martin T.; Tidemand-Lichtenberg, Peter

2008-02-01

We present a generic approach for efficient generation of CW light with a predetermined wavelength within the visible or UV spectrum. Based on sum-frequency generation (SFG), the circulating intra-cavity field of a high-finesse diode pumped CW solid-state laser (DPSSL) and the output from a tapered, single-frequency external cavity diode laser (ECDL) are mixed inside a 10 mm periodically poled KTP crstal (pp-KTP). The pp-KTP is situated inside the DPSSL cavity to enhance conversion efficiency of the nonlinear mixing process. This approach combines different solid state technologies; the tuneability of ECDLs, the high intra-cavity filed of DPSSLs and flexible quasi phase matching in pp-tapered ECDL with a center wavelength of 766 nm in combination with a high finesse Nd:YVo4 laser at 1342 nm. Up to 308 mW of light at 488nm was measured in our experiments. The conversion of te ECDL beam was up to 47% after it was transmitted through a PM fiber, and up to 32% without fiber coupling. Replacing the seed laser and the nonlinear crystal makes it possible to generate light at virtually any desired wavelength withing the visible spectrum.

Laser beam riding guided system principle and design research

NASA Astrophysics Data System (ADS)

Qu, Zhou; Jin, Yi; Xu, Zhou; Xing, Hao

2016-01-01

With the development of science and technology, precision-strike weapons has been considered to be important for winning victory in military field. Laser guidance is a major method to execute precision-strike in modern warfare. At present, the problems of primary stage of Laser guidance has been solved with endeavors of countries. Several technical aspects of laser-beam riding guided system have been mature, such as atmosphere penetration of laser beam, clutter inhibition on ground, laser irradiator, encoding and decoding of laser beam. Further, laser beam quality, equal output power and atmospheric transmission properties are qualified for warfare situation. Riding guidance instrument is a crucial element of Laser-beam riding guided system, and is also a vital element of airborne, vehicle-mounted and individual weapon. The optical system mainly consist of sighting module and laser-beam guided module. Photoelectric detector is the most important sensing device of seeker, and also the key to acquire the coordinate information of target space. Currently, in consideration of the 1.06 u m of wavelength applied in all the semi-active laser guided weapons systems, lithium drifting silicon photodiode which is sensitive to 1.06 u m of wavelength is used in photoelectric detector. Compared to Solid and gas laser, diode laser has many merits such as small volume, simple construction, light weight, long life, low lost and easy modulation. This article introduced the composition and operating principle of Laser-beam riding guided system based on 980 nm diode laser, and made a analysis of key technology; for instance, laser irradiator, modulating disk of component, laser zooming system. Through the use of laser diode, Laser-beam riding guided system is likely to have smaller shape and very light.

Target isolation system, high power laser and laser peening method and system using same

DOEpatents

Dane, C. Brent; Hackel, Lloyd A.; Harris, Fritz

2007-11-06

A system for applying a laser beam to work pieces, includes a laser system producing a high power output beam. Target delivery optics are arranged to deliver the output beam to a target work piece. A relay telescope having a telescope focal point is placed in the beam path between the laser system and the target delivery optics. The relay telescope relays an image between an image location near the output of the laser system and an image location near the target delivery optics. A baffle is placed at the telescope focal point between the target delivery optics and the laser system to block reflections from the target in the target delivery optics from returning to the laser system and causing damage.

Laser-Ultrasonic Testing and its Applications to Nuclear Reactor Internals

NASA Astrophysics Data System (ADS)

Ochiai, M.; Miura, T.; Yamamoto, S.

2008-02-01

A new nondestructive testing technique for surface-breaking microcracks in nuclear reactor components based on laser-ultrasonics is developed. Surface acoustic wave generated by Q-switched Nd:YAG laser and detected by frequency-stabilized long pulse laser coupled with confocal Fabry-Perot interferometer is used to detect and size the cracks. A frequency-domain signal processing is developed to realize accurate sizing capability. The laser-ultrasonic testing allows the detection of surface-breaking microcrack having a depth of less than 0.1 mm, and the measurement of their depth with an accuracy of 0.2 mm when the depth exceeds 0.5 mm including stress corrosion cracking. The laser-ultrasonic testing system combined with laser peening system, which is another laser-based maintenance technology to improve surface stress, for inner surface of small diameter tube is developed. The generation laser in the laser-ultrasonic testing system can be identical to the laser source of the laser peening. As an example operation of the system, the system firstly works as the laser-ultrasonic testing mode and tests the inner surface of the tube. If no cracks are detected, the system then changes its work mode to the laser peening and improves surface stress to prevent crack initiation. The first nuclear industrial application of the laser-ultrasonic testing system combined with the laser peening was completed in Japanese nuclear power plant in December 2004.

Optical Coherence Tomography Angiography of Retinal Cavernous Hemangioma.

PubMed

Pierro, Luisa; Marchese, Alessandro; Gagliardi, Marco; Bandello, Francesco

2017-08-01

Retinal cavernous hemangioma is a rare, benign, retinal tumor characterized by angiomatous proliferation of vessels within the inner retina or the optic disc.1 Here we report a case of retinal cavernous hemangioma on the margin of the optic disc in the right eye of a 61-year-old asymptomatic female. The lesion was studied with multimodal imaging which included structural optical coherence tomography, fluorescein angiography, blue fundus auto-fluorescence, optical coherence tomography angiography (OCTA) (DRI OCT Triton; Topcon, Tokyo, Japan) and visual field examination. Blood circulation inside retinal cavernous hemangioma lesion is typically low-stagnant.2 However, OCTA demonstrated blood flow inside the lesion, illustrating its vascular circulation.3 Visual field was within the normal limits, except from a slight enlargement of the blind spot. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:684-685.]. Copyright 2017, SLACK Incorporated.

Solid-state coherent laser radar wind shear measuring systems

NASA Technical Reports Server (NTRS)

Huffaker, R. Milton

1992-01-01

Coherent Technologies, Inc. (CTI) was established in 1984 to engage in the development of coherent laser radar systems and subsystems with applications in atmospheric remote sensing, and in target tracking, ranging and imaging. CTI focuses its capabilities in three major areas: (1) theoretical performance and design of coherent laser radar system; (2) development of coherent laser radar systems for government agencies such as DoD and NASA; and (3) development of coherent laser radar systems for commercial markets. The topics addressed are: (1) 1.06 micron solid-state coherent laser radar system; (2) wind measurement using 1.06 micron system; and flashlamp-pumped 2.09 micron solid-state coherent laser radar system.

Tachykinin-1 in the central nervous system regulates adiposity in rodents.

PubMed

Trivedi, Chitrang; Shan, Xiaoye; Tung, Yi-Chun Loraine; Kabra, Dhiraj; Holland, Jenna; Amburgy, Sarah; Heppner, Kristy; Kirchner, Henriette; Yeo, Giles S H; Perez-Tilve, Diego

2015-05-01

Ghrelin is a circulating hormone that targets the central nervous system to regulate feeding and adiposity. The best-characterized neural system that mediates the effects of ghrelin on energy balance involves the activation of neuropeptide Y/agouti-related peptide neurons, expressed exclusively in the arcuate nucleus of the hypothalamus. However, ghrelin receptors are expressed in other neuronal populations involved in the control of energy balance. We combined laser capture microdissection of several nuclei of the central nervous system expressing the ghrelin receptor (GH secretagoge receptor) with microarray gene expression analysis to identify additional neuronal systems involved in the control of central nervous system-ghrelin action. We identified tachykinin-1 (Tac1) as a gene negatively regulated by ghrelin in the hypothalamus. Furthermore, we identified neuropeptide k as the TAC1-derived peptide with more prominent activity, inducing negative energy balance when delivered directly into the brain. Conversely, loss of Tac1 expression enhances the effectiveness of ghrelin promoting fat mass gain both in male and in female mice and increases the susceptibility to diet-induced obesity in ovariectomized mice. Taken together, our data demonstrate a role TAC1 in the control energy balance by regulating the levels of adiposity in response to ghrelin administration and to changes in the status of the gonadal function.

21 CFR 884.6200 - Assisted reproduction laser system.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Assisted reproduction laser system. 884.6200... Assisted reproduction laser system. (a) Identification. The assisted reproduction laser system is a device that images, targets, and controls the power and pulse duration of a laser beam used to ablate a small...

21 CFR 884.6200 - Assisted reproduction laser system.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Assisted reproduction laser system. 884.6200... Assisted reproduction laser system. (a) Identification. The assisted reproduction laser system is a device that images, targets, and controls the power and pulse duration of a laser beam used to ablate a small...

21 CFR 884.6200 - Assisted reproduction laser system.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Assisted reproduction laser system. 884.6200... Assisted reproduction laser system. (a) Identification. The assisted reproduction laser system is a device that images, targets, and controls the power and pulse duration of a laser beam used to ablate a small...

21 CFR 884.6200 - Assisted reproduction laser system.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Assisted reproduction laser system. 884.6200... Assisted reproduction laser system. (a) Identification. The assisted reproduction laser system is a device that images, targets, and controls the power and pulse duration of a laser beam used to ablate a small...

21 CFR 884.6200 - Assisted reproduction laser system.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Assisted reproduction laser system. 884.6200... Assisted reproduction laser system. (a) Identification. The assisted reproduction laser system is a device that images, targets, and controls the power and pulse duration of a laser beam used to ablate a small...

Laser system using ultra-short laser pulses

DOEpatents

Dantus, Marcos [Okemos, MI; Lozovoy, Vadim V [Okemos, MI; Comstock, Matthew [Milford, MI

2009-10-27

A laser system using ultrashort laser pulses is provided. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and a SHG crystal.

Airborne laser sensors and integrated systems

NASA Astrophysics Data System (ADS)

Sabatini, Roberto; Richardson, Mark A.; Gardi, Alessandro; Ramasamy, Subramanian

2015-11-01

The underlying principles and technologies enabling the design and operation of airborne laser sensors are introduced and a detailed review of state-of-the-art avionic systems for civil and military applications is presented. Airborne lasers including Light Detection and Ranging (LIDAR), Laser Range Finders (LRF), and Laser Weapon Systems (LWS) are extensively used today and new promising technologies are being explored. Most laser systems are active devices that operate in a manner very similar to microwave radars but at much higher frequencies (e.g., LIDAR and LRF). Other devices (e.g., laser target designators and beam-riders) are used to precisely direct Laser Guided Weapons (LGW) against ground targets. The integration of both functions is often encountered in modern military avionics navigation-attack systems. The beneficial effects of airborne lasers including the use of smaller components and remarkable angular resolution have resulted in a host of manned and unmanned aircraft applications. On the other hand, laser sensors performance are much more sensitive to the vagaries of the atmosphere and are thus generally restricted to shorter ranges than microwave systems. Hence it is of paramount importance to analyse the performance of laser sensors and systems in various weather and environmental conditions. Additionally, it is important to define airborne laser safety criteria, since several systems currently in service operate in the near infrared with considerable risk for the naked human eye. Therefore, appropriate methods for predicting and evaluating the performance of infrared laser sensors/systems are presented, taking into account laser safety issues. For aircraft experimental activities with laser systems, it is essential to define test requirements taking into account the specific conditions for operational employment of the systems in the intended scenarios and to verify the performance in realistic environments at the test ranges. To support the development of such requirements, useful guidelines are provided for test and evaluation of airborne laser systems including laboratory, ground and flight test activities.

The simulation study on optical target laser active detection performance

NASA Astrophysics Data System (ADS)

Li, Ying-chun; Hou, Zhao-fei; Fan, Youchen

2014-12-01

According to the working principle of laser active detection system, the paper establishes the optical target laser active detection simulation system, carry out the simulation study on the detection process and detection performance of the system. For instance, the performance model such as the laser emitting, the laser propagation in the atmosphere, the reflection of optical target, the receiver detection system, the signal processing and recognition. We focus on the analysis and modeling the relationship between the laser emitting angle and defocus amount and "cat eye" effect echo laser in the reflection of optical target. Further, in the paper some performance index such as operating range, SNR and the probability of the system have been simulated. The parameters including laser emitting parameters, the reflection of the optical target and the laser propagation in the atmosphere which make a great influence on the performance of the optical target laser active detection system. Finally, using the object-oriented software design methods, the laser active detection system with the opening type, complete function and operating platform, realizes the process simulation that the detection system detect and recognize the optical target, complete the performance simulation of each subsystem, and generate the data report and the graph. It can make the laser active detection system performance models more intuitive because of the visible simulation process. The simulation data obtained from the system provide a reference to adjust the structure of the system parameters. And it provides theoretical and technical support for the top level design of the optical target laser active detection system and performance index optimization.

Injection mode-locking Ti-sapphire laser system

DOEpatents

Hovater, James Curtis; Poelker, Bernard Matthew

2002-01-01

According to the present invention there is provided an injection modelocking Ti-sapphire laser system that produces a unidirectional laser oscillation through the application of a ring cavity laser that incorporates no intracavity devices to achieve unidirectional oscillation. An argon-ion or doubled Nd:YVO.sub.4 laser preferably serves as the pump laser and a gain-switched diode laser serves as the seed laser. A method for operating such a laser system to produce a unidirectional oscillating is also described.

Planning for Downtown Circulation Systems. Volume 1. Planning Concepts.

DOT National Transportation Integrated Search

1983-10-01

This document brings together the state-of-the-art in planning concepts, methods and data for use by those cities proposing or considering comprehensive or innovative downtown circulation systems, particularly Downtown People Mover systems. DPM syste...

Potential use of lasers for penetrating keratoplasty.

PubMed

Thompson, K P; Barraquer, E; Parel, J M; Loertscher, H; Pflugfelder, S; Roussel, T; Holland, S; Hanna, K

1989-07-01

Experimental corneal trephination has been achieved with the 193 nm argon fluoride excimer and 2.9 microns hydrogen fluoride and Er:YAG laser systems. Compared with metal blades and other lasers, the 193 nm excimer laser creates the best quality corneal excision, but has a relatively slow etch rate through the stroma, and its use requires toxic gas. The mid-infrared laser systems trephine the cornea in less than 10 seconds, but cause a 10 microns to 15 microns zone of adjacent stromal damage and create wounds that are approximately 2.5 times larger than wounds made by metal scalpels. The wavelength and laser pulse duration influence the cutting characteristics of the laser. Optical delivery systems using an axicon lens, a rotating slit, and a computer controlled scanning optical system have been developed for penetrating keratoplasty. Selection of the optimal laser system for penetrating keratoplasty must await further experimental studies. Refinements of the laser cavity and delivery system are necessary before clinical studies can begin. A carefully controlled randomized clinical trial comparing laser trephination with conventional mechanical trephines will be necessary to determine the safety and efficacy of a laser trephination system.

Amelioration of Cardiac Function and Activation of Anti-Inflammatory Vasoactive Peptides Expression in the Rat Myocardium by Low Level Laser Therapy

PubMed Central

Manchini, Martha Trindade; Serra, Andrey Jorge; Feliciano, Regiane dos Santos; Santana, Eduardo Tadeu; Antônio, Ednei Luis; de Tarso Camillo de Carvalho, Paulo; Montemor, Jairo; Crajoinas, Renato Oliveira; Girardi, Adriana Castello Costa; Tucci, Paulo José Ferreira; Silva, José Antônio

2014-01-01

Low-level laser therapy (LLLT) has been used as an anti-inflammatory treatment in several disease conditions, even when inflammation is a secondary consequence, such as in myocardial infarction (MI). However, the mechanism by which LLLT is able to protect the remaining myocardium remains unclear. The present study tested the hypothesis that LLLT reduces inflammation after acute MI in female rats and ameliorates cardiac function. The potential participation of the Renin-Angiotensin System (RAS) and Kallikrein-Kinin System (KKS) vasoactive peptides was also evaluated. LLLT treatment effectively reduced MI size, attenuated the systolic dysfunction after MI, and decreased the myocardial mRNA expression of interleukin-1 beta and interleukin-6 in comparison to the non-irradiated rat tissue. In addition, LLLT treatment increased protein and mRNA levels of the Mas receptor, the mRNA expression of kinin B2 receptors and the circulating levels of plasma kallikrein compared to non-treated post-MI rats. On the other hand, the kinin B1 receptor mRNA expression decreased after LLLT. No significant changes were found in the expression of vascular endothelial growth factor (VEGF) in the myocardial remote area between laser-irradiated and non-irradiated post-MI rats. Capillaries density also remained similar between these two experimental groups. The mRNA expression of the inducible nitric oxide synthase (iNOS) was increased three days after MI, however, this effect was blunted by LLLT. Moreover, endothelial NOS mRNA content increased after LLLT. Plasma nitric oxide metabolites (NOx) concentration was increased three days after MI in non-treated rats and increased even further by LLLT treatment. Our data suggest that LLLT diminishes the acute inflammation in the myocardium, reduces infarct size and attenuates left ventricle dysfunction post-MI and increases vasoactive peptides expression and nitric oxide (NO) generation. PMID:24991808

Long distance high power optical laser fiber break detection and continuity monitoring systems and methods

DOEpatents

Rinzler, Charles C.; Gray, William C.; Faircloth, Brian O.; Zediker, Mark S.

2016-02-23

A monitoring and detection system for use on high power laser systems, long distance high power laser systems and tools for performing high power laser operations. In particular, the monitoring and detection systems provide break detection and continuity protection for performing high power laser operations on, and in, remote and difficult to access locations.

Automated Bilingual Circulation System Using PC Local Area Networks.

ERIC Educational Resources Information Center

Iskanderani, A. I.; Anwar, M. A.

1992-01-01

Describes a personal computer and LAN-based automated circulation system capable of handling both Arabic and Latin characters that was developed for use at King Abdullaziz University (Jeddah, Saudi Arabia). Outlines system requirements, system structure, hardware needs, and individual functional modules of the system. Numerous examples and flow…

Heterodyne laser spectroscopy system

DOEpatents

Wyeth, Richard W.; Paisner, Jeffrey A.; Story, Thomas

1990-01-01

A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency, and provides spectral analysis of a laser beam.

Increased numbers of circulating ECs are associated with systemic GVHD.

PubMed

Yan, Z; Zeng, L; Jia, L; Xu, S; Ding, S

2011-10-01

Circulating endothelial cells (ECs) are known to reflect endothelial injury, and endothelial injury is associated with graft-versus-host disease (GVHD). We hypothesised that circulating ECs might be associated with systemic acute graft-versus-host disease (aGVHD). BALB/c (H-2k(d) ) mice were treated with total body irradiation and then infused with C57B/6-derived T-cell-depleted bone marrow (TCD-BM) cells or TCD-BM cells and splenocytes. Cyclosporine was used to prevent aGVHD. Circulating ECs and allogeneic lymphocytes were analysed by flow cytometry at multiple time points. The morphology and ultrastructure of the endothelium were examined by light microscopy or transmission electron microscopy. The results indicated that the number of circulating ECs peaked at day 5 after lethal irradiation in all mice; allogenic transplanted mice (TCD-BM cells and splenocytes) developed typical aGVHD beginning at day 7, exhibiting both histological and clinical symptoms of disease. Circulating ECs peaked a second time at day 9 with aGVHD progression. However, following the administration of CSA, an absence of or a reduction in the amount of subsequent endothelial injury was observed. Circulating ECs might be associated with systemic aGVHD. © 2011 Blackwell Publishing Ltd.

Research on the Impact of a Computerized Circulation System on the Performance of a Large College Library. Final Report.

ERIC Educational Resources Information Center

Frohmberg, Katherine A.; Moffett, William A.

In order to study the effects of introducing an automated circulation system at Oberlin College, Ohio, data were collected from September 1978 until June 1982 on book availability, usage of library facilities, attitudes of library users toward the library, and the efficiency of circulation activities. Data collection methods included circulation…

Systems Analysis, Machineable Circulation Data and Library Users and Non-Users.

ERIC Educational Resources Information Center

Lubans, John, Jr.

A study to be made with computer-based circulation data of the non-use and use of a large academic library is discussed. A search of the literature reveals that computer-based circulation systems can be, but have not been, utilized to provide data bases for systematic analyses of library users and resources. The data gathered in the circulation…

Mechanization in a New Medical School Library II. Serials and Circulation

PubMed Central

Payne, Ladye Margarete; Small, Louise; Divett, Robert T.

1966-01-01

The serials and circulation phases of the data-processing system in use at the University of New Mexico Library of the Medical Sciences are described. The development of the programs is also reported. The serials program uses simple punched card equipment. The circulation program uses the IBM 357 Data Collection System and punched card data-processing equipment. Images PMID:5921473

Comparison of different laser systems in the treatment of hypertrophic and atrophic scars and keloids

NASA Astrophysics Data System (ADS)

Scharschmidt, D.; Algermissen, Bernd; Willms-Jones, J.-C.; Philipp, Carsten M.; Berlien, Hans-Peter

1997-12-01

Different laser systems and techniques are used for the treatment of hypertrophic scars, keloids and acne scars. Significant criteria in selecting a suitable laser system are the scar's vascularization, age and diameter. Flashlamp- pumped dye-lasers, CO2-lasers with scanner, Argon and Nd:YAG-lasers are used. Telangiectatic scars respond well to argon lasers, erythematous scars and keloids to dye-laser treatment. Using interstitial Nd:YAG-laser vaporization, scars with a cross-section over 1 cm can generally be reduced. For the treatment of atrophic and acne scars good cosmetic results are achieved with a CO2-laser/scanner system, which allows a precise ablation of the upper dermis with low risk of side-effects.

Heterodyne laser spectroscopy system

DOEpatents

Wyeth, Richard W.; Paisner, Jeffrey A.; Story, Thomas

1989-01-01

A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency and the like, and provides spectral analysis of a laser beam.

The Geoscience Laser Altimeter System Laser Transmitter

NASA Technical Reports Server (NTRS)

Afzal, R. S.; Dallas, J. L.; Yu, A. W.; Mamakos, W. A.; Lukemire, A.; Schroeder, B.; Malak, A.

2000-01-01

The Geoscience Laser Altimeter System (GLAS), scheduled to launch in 2001, is a laser altimeter and lidar for tile Earth Observing System's (EOS) ICESat mission. The laser transmitter requirements, design and qualification test results for this space- based remote sensing instrument are presented.

36 CFR 910.17 - Pedestrian circulation system.

Code of Federal Regulations, 2010 CFR

2010-07-01

... GENERAL GUIDELINES AND UNIFORM STANDARDS FOR URBAN PLANNING AND DESIGN OF DEVELOPMENT WITHIN THE PENNSYLVANIA AVENUE DEVELOPMENT AREA Urban Planning and Design Concerns § 910.17 Pedestrian circulation system...

36 CFR 910.17 - Pedestrian circulation system.

Code of Federal Regulations, 2011 CFR

2011-07-01

... GENERAL GUIDELINES AND UNIFORM STANDARDS FOR URBAN PLANNING AND DESIGN OF DEVELOPMENT WITHIN THE PENNSYLVANIA AVENUE DEVELOPMENT AREA Urban Planning and Design Concerns § 910.17 Pedestrian circulation system...

The Geoscience Laser Altimeter System (GLAS) Laser Transmitter

NASA Technical Reports Server (NTRS)

Afzal, Robert S.; Yu, Anthony W.; Dallas, Joseph L.; Melak, Anthony; Lukemir, Alan; Ramos-Izqueirdo, L.; Mamakos, William

2007-01-01

The Geoscience Laser Altimeter System (GLAS), launched in January 2003, is a laser altimeter and lidar for the Earth Observing System's (EOS) ICESat mission. GLAS accommodates three, sequentially operated, diode-pumped, solid-state, Nd:YAG laser transmitters. The laser transmitter requirements, design and qualification test results for this space-based remote sensing instrument is summarized and presented

Laser ablation system, and method of decontaminating surfaces

DOEpatents

Ferguson, Russell L.; Edelson, Martin C.; Pang, Ho-ming

1998-07-14

A laser ablation system comprising a laser head providing a laser output; a flexible fiber optic cable optically coupled to the laser output and transmitting laser light; an output optics assembly including a nozzle through which laser light passes; an exhaust tube in communication with the nozzle; and a blower generating a vacuum on the exhaust tube. A method of decontaminating a surface comprising the following steps: providing an acousto-optic, Q-switched Nd:YAG laser light ablation system having a fiber optically coupled output optics assembly; and operating the laser light ablation system to produce an irradiance greater than 1.times.10.sup.7 W/cm.sup.2, and a pulse width between 80 and 170 ns.

Comparison of three different laser systems for application in dentistry

NASA Astrophysics Data System (ADS)

Mindermann, Anja; Niemz, M. H.; Eisenmann, L.; Loesel, Frieder H.; Bille, Josef F.

1993-12-01

Three different laser systems have been investigated according to their possible application in dentistry: a free running and a Q-switched microsecond Ho:YAG laser, a free running microsecond Er:YAG laser and picosecond Nd:YLF laser system consisting of an actively mode locked oscillator and a regenerative amplifier. The experiments focused on the question if lasers can support or maybe replace ordinary drilling machines. For this purpose several cavities were generated with the lasers mentioned above. Their depth and quality were judged by light and electron microscopy. The results of the experiments showed that the picosecond Nd:YLF laser system has advantages compared to other lasers regarding their application in dentistry.

Laser Safety and Hazardous Analysis for the ARES (Big Sky) Laser System

DOE Office of Scientific and Technical Information (OSTI.GOV)

AUGUSTONI, ARNOLD L.

A laser safety and hazard analysis was performed for the ARES laser system based on the 2000 version of the American National Standards Institute's (ANSI) Standard Z136.1,for Safe Use of Lasers and the 2000 version of the ANSI Standard Z136.6, for Safe Use of Lasers Outdoors. The ARES laser system is a Van/Truck based mobile platform, which is used to perform laser interaction experiments and tests at various national test sites.

Lunar and Artificial Satellite Laser Ranging: The Use of Queue Scheduling and Worth Functions to Maximize Scientific Results

NASA Astrophysics Data System (ADS)

Shelus, P. J.; Ricklefs, R. L.; Wiant, J. R.; Ries, J. G.

2003-08-01

The lunar and artificial satellite laser ranging network, part of the International Laser Ranging Service, monitors a large number of targets. Many scientific disciplines are investigated using these data. These include the realization and maintenance of the International Terrestrial Reference Frame; the 3-dimensional deformation of the solid Earth; Earth orientation; variations in the topography and volume of the liquid Earth, including ocean circulation, mean sea level, ice sheet thickness, and wave heights; tidally generated variations in atmospheric mass distribution; calibration of microwave tracking techniques; picosecond global time transfer; determination of the dynamic equinox, the obliquity of the ecliptic, the precession constant and theories of nutation; gravitational and general relativistic studies, including Einstein's Equivalence Principle, the Robertson-Walker b parameter and time rate of change of the gravitational constant; lunar physics, including the dissipation of rotational energy, shape of the core-mantle boundary (Love Number k2), and free librations and their stimulating mechanisms; Solar System ties to the International Celestial Reference Frame. With shrinking resources, we must not only assess specific data requirements for each target, but also maximize the efficiency of the observing network. Several factors must be considered. First, not only does a result depend critically upon the quality and quantity of the data, it also depends upon the data distribution. Second, as technology improves, the cost of obtaining data can increase. Both require that scientific endeavor pay close attention to the manner in which the data is gathered. We examine the evolution of the laser network, using data analysis requirements and efficient network scheduling to maximize the scientific return. This requires an understanding of the observing equipment, as well as the scientific principles being studied. Queue scheduling and worth functions become important. This work is funded by: NSF AST-0204127, NASA NAG5-10195, NAS5-01096, NAG5-11464.

X-band RF gun and linac for medical Compton scattering X-ray source

NASA Astrophysics Data System (ADS)

Dobashi, Katsuhito; Uesaka, Mitsuru; Fukasawa, Atsushi; Sakamoto, Fumito; Ebina, Futaro; Ogino, Haruyuki; Urakawa, Junji; Higo, Toshiyasu; Akemoto, Mitsuo; Hayano, Hitoshi; Nakagawa, Keiichi

2004-12-01

Compton scattering hard X-ray source for 10-80 keV are under construction using the X-band (11.424 GHz) electron linear accelerator and YAG laser at Nuclear Engineering Research laboratory, University of Tokyo. This work is a part of the national project on the development of advanced compact medical accelerators in Japan. National Institute for Radiological Science is the host institute and U.Tokyo and KEK are working for the X-ray source. Main advantage is to produce tunable monochromatic hard (10-80 keV) X-rays with the intensities of 108-1010 photons/s (at several stages) and the table-top size. Second important aspect is to reduce noise radiation at a beam dump by adopting the deceleration of electrons after the Compton scattering. This realizes one beamline of a 3rd generation SR source at small facilities without heavy shielding. The final goal is that the linac and laser are installed on the moving gantry. We have designed the X-band (11.424 GHz) traveling-wave-type linac for the purpose. Numerical consideration by CAIN code and luminosity calculation are performed to estimate the X-ray yield. X-band thermionic-cathode RF-gun and RDS(Round Detuned Structure)-type X-band accelerating structure are applied to generate 50 MeV electron beam with 20 pC microbunches (104) for 1 microsecond RF macro-pulse. The X-ray yield by the electron beam and Q-switch Nd:YAG laser of 2 J/10 ns is 107 photons/RF-pulse (108 photons/sec at 10 pps). We design to adopt a technique of laser circulation to increase the X-ray yield up to 109 photons/pulse (1010 photons/s). 50 MW X-band klystron and compact modulator have been constructed and now under tuning. The construction of the whole system has started. X-ray generation and medical application will be performed in the early next year.

Using a Gravity Model to Predict Circulation in a Public Library System.

ERIC Educational Resources Information Center

Ottensmann, John R.

1995-01-01

Describes the development of a gravity model based upon principles of spatial interaction to predict the circulation of libraries in the Indianapolis-Marion County Public Library (Indiana). The model effectively predicted past circulation figures and was tested by predicting future library circulation, particularly for a new branch library.…

Laser power conversion system analysis, volume 2

NASA Technical Reports Server (NTRS)

Jones, W. S.; Morgan, L. L.; Forsyth, J. B.; Skratt, J. P.

1979-01-01

The orbit-to-ground laser power conversion system analysis investigated the feasibility and cost effectiveness of converting solar energy into laser energy in space, and transmitting the laser energy to earth for conversion to electrical energy. The analysis included space laser systems with electrical outputs on the ground ranging from 100 to 10,000 MW. The space laser power system was shown to be feasible and a viable alternate to the microwave solar power satellite. The narrow laser beam provides many options and alternatives not attainable with a microwave beam.

Applications of lasers and electro-optics

NASA Astrophysics Data System (ADS)

Tan, B. C.; Low, K. S.; Chen, Y. H.; Ahmad, Harith; Tou, T. Y.

Supported by the IRPA Programme on Laser Technology and Applications, many types of lasers have been designed, constructed and applied in various areas of science, medicine and industries. Amongst these lasers constructed were high power carbon dioxide lasers, rare gas halide excimer lasers, solid state Neodymium-YAG lasers, nitrogen lasers, flashlamp pumped dye lasers and nitrogen and excimer laser pumped dye lasers. These lasers and the associated electro-optics system, some with computer controlled, are designed and developed for the following areas of applications: (1) industrial applications of high power carbon dioxide lasers for making of i.c. components and other materials processing purposes -- prototype operational systems have been developed; (2) Medical applications of lasers for cancer treatment using the technique of photodynamic therapy -- a new and more effective treatment protocol has been proposed; (3) agricultural applications of lasers in palm oil and palm fruit-fluorescence diagnostic studies -- fruit ripeness signature has been developed and palm oil oxidation level were investigated; (4) development of atmospheric pollution monitoring systems using laser lidar techniques -- laboratory scale systems were developed; and (5) other applications of lasers including laser holographic and interferometric methods for the non destructive testing of materials.

Technology Development of a Fiber Optic-Coupled Laser Ignition System for Multi-Combustor Rocket Engines

NASA Technical Reports Server (NTRS)

Trinh, Huu P.; Early, Jim; Osborne, Robin; Thomas, Matthew E.; Bossard, John A.

2002-01-01

This paper addresses the progress of technology development of a laser ignition system at NASA Marshall Space Flight Center (MSFC). The first two years of the project focus on comprehensive assessments and evaluations of a novel dual-pulse laser concept, flight- qualified laser system, and the technology required to integrate the laser ignition system to a rocket chamber. With collaborations of the Department of Energy/Los Alamos National Laboratory (LANL) and CFD Research Corporation (CFDRC), MSFC has conducted 26 hot fire ignition tests with lab-scale laser systems. These tests demonstrate the concept feasibility of dual-pulse laser ignition to initiate gaseous oxygen (GOX)/liquid kerosene (RP-1) combustion in a rocket chamber. Presently, a fiber optic- coupled miniaturized laser ignition prototype is being implemented at the rocket chamber test rig for future testing. Future work is guided by a technology road map that outlines the work required for maturing a laser ignition system. This road map defines activities for the next six years, with the goal of developing a flight-ready laser ignition system.

On the glacial and interglacial thermohaline circulation and the associated transports of heat and freshwater

NASA Astrophysics Data System (ADS)

Ballarotta, M.; Falahat, S.; Brodeau, L.; Döös, K.

2014-11-01

The thermohaline circulation (THC) and the oceanic heat and freshwater transports are essential for understanding the global climate system. Streamfunctions are widely used in oceanography to represent the THC and estimate the transport of heat and freshwater. In the present study, the regional and global changes of the THC, the transports of heat and freshwater and the timescale of the circulation between the Last Glacial Maximum (LGM, ≈ 21 kyr ago) and the present-day climate are explored using an Ocean General Circulation Model and streamfunctions projected in various coordinate systems. We found that the LGM tropical circulation is about 10% stronger than under modern conditions due to stronger wind stress. Consequently, the maximum tropical transport of heat is about 20% larger during the LGM. In the North Atlantic basin, the large sea-ice extent during the LGM constrains the Gulf Stream to propagate in a more zonal direction, reducing the transport of heat towards high latitudes by almost 50% and reorganising the freshwater transport. The strength of the Atlantic Meridional Overturning Circulation depends strongly on the coordinate system. It varies between 9 and 16 Sv during the LGM, and between 12 to 19 Sv for the present day. Similar to paleo-proxy reconstructions, a large intrusion of saline Antarctic Bottom Water takes place into the Northern Hemisphere basins and squeezes most of the Conveyor Belt circulation into a shallower part of the ocean. These different haline regimes between the glacial and interglacial period are illustrated by the streamfunctions in latitude-salinity coordinates and thermohaline coordinates. From these diagnostics, we found that the LGM Conveyor Belt circulation is driven by an enhanced salinity contrast between the Atlantic and the Pacific basin. The LGM abyssal circulation lifts and makes the Conveyor Belt cell deviate from the abyssal region, resulting in a ventilated upper layer above a deep stagnant layer, and an Atlantic circulation more isolated from the Pacific. An estimate of the timescale of the circulation reveals a sluggish abyssal circulation during the LGM, and a Conveyor Belt circulation that is more vigorous due to the combination of a stronger wind stress and a shortened circulation route.

The pulsed dye laser versus the Q-switched Nd:YAG laser in laser-induced shock-wave lithotripsy.

PubMed

Thomas, S; Pensel, J; Engelhardt, R; Meyer, W; Hofstetter, A G

1988-01-01

To date, there are two fairly well-established alternatives for laser-induced shock-wave lithotripsy in clinical practice. The Q-switched Nd:YAG laser is distinguished by the high-stone selectivity of its coupler systems. The necessity of a coupler system and its fairly small conversion rate of light energy into mechanical energy present serious drawbacks. Furthermore, the minimal outer diameter of the transmission system is 1.8 mm. The pulsed-dye laser can be used with a highly flexible and uncomplicated 200-micron fiber. However, the laser system itself is more complicated than the Q-switched Nd:YAG laser and requires a great deal of maintenance. Biological evaluation of damage caused by direct irradiation shows that both laser systems produce minor damage of different degrees. YAG laser lithotripsy with the optomechanical coupler was assessed in 31 patients with ureteral calculi. The instability and limited effectiveness of the fiber application system necessitated auxiliary lithotripsy methods in 14 cases. Dye-laser lithotripsy is currently being tested in clinical application. Further development, such as systems for blind application or electronic feedback mechanisms to limit adverse tissue effects, have yet to be optimized. Nevertheless, laser-induced shock-wave lithotripsy has the potential to become a standard procedure in the endourologic management of stone disease.

Investigation of possibilities for solar-powered high-energy lasers in space

NASA Technical Reports Server (NTRS)

1982-01-01

Solar pumped lasers were investigated. The literature was reviewed for possible solar laser candidates from optical pumping experiments. A baseline CO electric discharge laser system was shown to be technically feasible. The most promising direct solar pumped laser was identified to be CF3I. Using the 'STAG' solar laser concept and CF3I, it was found that such a system could be weight competitive with the baseline CO laser system.

High throughput laser processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harley, Gabriel; Pass, Thomas; Cousins, Peter John

A solar cell is formed using a solar cell ablation system. The ablation system includes a single laser source and several laser scanners. The laser scanners include a master laser scanner, with the rest of the laser scanners being slaved to the master laser scanner. A laser beam from the laser source is split into several laser beams, with the laser beams being scanned onto corresponding wafers using the laser scanners in accordance with one or more patterns. The laser beams may be scanned on the wafers using the same or different power levels of the laser source.

Development of a US Gravitational Wave Laser System for LISA

NASA Technical Reports Server (NTRS)

Camp, Jordan B.; Numata, Kenji

2015-01-01

A highly stable and robust laser system is a key component of the space-based LISA mission architecture.In this talk I will describe our plans to demonstrate a TRL 5 LISA laser system at Goddard Space Flight Center by 2016.The laser system includes a low-noise oscillator followed by a power amplifier. The oscillator is a low-mass, compact 10mW External Cavity Laser, consisting of a semiconductor laser coupled to an optical cavity, built by the laser vendorRedfern Integrated Optics. The amplifier is a diode-pumped Yb fiber with 2W output, built at Goddard. I will show noiseand reliability data for the full laser system, and describe our plans to reach TRL 5 by 2016.

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Caldwell, Loren M. (Inventor); Tang, Shoou-yu (Inventor); O'Brien, Martin (Inventor)

2010-01-01

Systems and methods for sensing air outside a moving aircraft are presented. In one embodiment, a system includes a laser for generating laser energy. The system also includes one or more transceivers for projecting the laser energy as laser radiation to the air. Subsequently, each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines one or more air parameters based on the scattered laser radiation. Such air parameters may include air speed, air pressure, air temperature and aircraft orientation angle, such as yaw, angle of attack and sideslip.

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Caldwell, Loren M. (Inventor); O'Brien, Martin J. (Inventor); Weimer, Carl S. (Inventor); Nelson, Loren D. (Inventor)

2008-01-01

Systems and methods for sensing air outside a moving aircraft are presented. In one embodiment, a system includes a laser for generating laser energy. The system also includes one or more transceivers for projecting the laser energy as laser radiation to the air. Subsequently, each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines one or more air parameters based on the scattered laser radiation. Such air parameters may include air speed, air pressure, air temperature and aircraft orientation angle, such as yaw, angle of attack and sideslip.

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Caldwell, Loren M. (Inventor); O'Brien, Martin J. (Inventor); Weimer, Carl S. (Inventor); Nelson, Loren D. (Inventor)

2005-01-01

Systems and methods for sensing air outside a moving aircraft are presented. In one embodiment, a system includes a laser for generating laser energy. The system also includes one or more transceivers for projecting the laser energy as laser radiation to the air. Subsequently, each transceiver receives laser energy as it is backscattered from the air. A computer processes signals from the transceivers to distinguish molecular scattered laser radiation from aerosol scattered laser radiation and determines one or more air parameters based on the scattered laser radiation. Such air parameters may include air speed, air pressure, air temperature and aircraft orientation angle, such as yaw, angle of attack and sideslip.

Tracking Control and System Development for Laser-Driven Micro-Vehicles

NASA Astrophysics Data System (ADS)

Kajiwara, Itsuro; Hoshino, Kentaro; Hara, Shinji; Shiokata, Daisuke; Yabe, Takashi

The purpose of this paper is to design a control system for an integrated laser propulsion/tracking system to achieve continuous motion and control of laser-driven micro-vehicles. Laser propulsion is significant in achieving miniature and light micro-vehicles. A laser-driven micro-airplane has been studied using a paper airplane and YAG laser, resulting in successful gliding of the airplane. High-performance laser tracking control is required to achieve continuous flight. This paper presents a control design strategy based on the generalized Kalman-Yakubovic-Popov lemma to achieve this requirement. Experiments have been carried out to evaluate the performance of the integrated laser propulsion/tracking system.

Laser-SPS systems analysis and environmental impact assessment

NASA Technical Reports Server (NTRS)

Beverly, R. E., III

1980-01-01

The systems feasibility and environmental impact of replacing the microwave transmitters on the Satellite Power System with laser transmitters are examined. The lasers suggested are two molecular-gas electric-discharge lasers (EDL's), namely the CO and CO2 lasers. Calculations are made on system efficiency, atmospheric transmission efficiency, and laser beam spreading. It is found that the present satellite concept using lasers is far too inefficient and massive to be economically viable. However, the safety issues associated with laser power transmission appear tractable, and no effects could be identified which present a real danger of serious injury to the environment, although certain phenomena deserve closer scrutiny.

The Automated Circulation Marketplace: Active and Heating Up.

ERIC Educational Resources Information Center

Matthews, Joseph R.

1982-01-01

Predicts that the growing market for automated circulation systems will expand even faster in the near future, given the availability of a wide variety of systems and computer types, which enables libraries of all sizes to obtain a system to fit their needs. Currently there are 301 systems installed. (RAA)

An Integrated Systems Approach: A Description of an Automated Circulation Management System.

ERIC Educational Resources Information Center

Seifert, Jan E.; And Others

These bidding specifications describe requirements for a turn-key automated circulation system for the University of Oklahoma Libraries. An integrated systems approach is planned, and requirements are presented for various subsystems: acquisitions, fund accounting, reserve room, and bibliographic and serials control. Also outlined are hardware…

Non-extracorporeal circulation for coronary artery bypass graft surgery is more beneficial than extracorporeal circulation.

PubMed

Yang, F-Y; Bao, Y-Z; Liu, F-S; Zhu, Y-C; Zheng, J; Zhang, J-H; Zheng, X-F; Wei, G-C

2015-04-01

The objective of this study was to compare coronary artery bypass graft (CABG) surgery with non-extracorporeal vs. extracorporeal circulation. The study outcomes included operative time, number of graft vessels, pulmonary infection rates, and systemic inflammatory markers. 96 patients received selective CABG, either with non-extracorporeal (study group; n = 48) or extracorporeal circulation (control group; n = 48). Operative time, pulmonary infection rates, and blood levels of inflammatory markers TNF-α, IL-6, and IL-8 before and 4, 24, and 48 hours after the surgery were quantified. Graft vessels were quantified using computed tomography. Operative time was significantly shorter in study group (4.58 ± 0.91 vs. 5.36 ± 1.12 hours in control group; p < 0.05). The number of graft vessels and pulmonary infection rates were comparable between both techniques. However, systemic inflammatory markers were significantly (p < 0.05) lower in study group at 4 and, partly, 24 hours after the surgery. Extracorporeal circulation prolongs operation and can aggravate systemic inflammatory response. Therefore, CABG with non-extracorporeal circulation offers more beneficial outcomes.

Performance and stability analysis of gas-injection enhanced natural circulation in heavy-liquid-metal-cooled systems

NASA Astrophysics Data System (ADS)

Yoo, Yeon-Jong

The purpose of this study is to investigate the performance and stability of the gas-injection enhanced natural circulation in heavy-liquid-metal-cooled systems. The target system is STAR-LM, which is a 400-MWt-class advanced lead-cooled fast reactor under development by Argonne National Laboratory and Oregon State University. The primary loop of STAR-LM relies on natural circulation to eliminate main circulation pumps for enhancement of passive safety. To significantly increase the natural circulation flow rate for the incorporation of potential future power uprates, the injection of noncondensable gas into the coolant above the core is envisioned ("gas lift pump"). Reliance upon gas-injection enhanced natural circulation raises the concern of flow instability due to the relatively high temperature change in the reactor core and the two-phase flow condition in the riser. For this study, the one-dimensional flow field equations were applied to each flow section and the mixture models of two-phase flow, i.e., both the homogeneous and drift-flux equilibrium models were used in the two-phase region of the riser. For the stability analysis, the linear perturbation technique based on the frequency-domain approach was used by employing the Nyquist stability criterion and a numerical root search method. It has been shown that the thermal power of the STAR-LM natural circulation system could be increased from 400 up to 1152 MW with gas injection under the limiting void fraction of 0.30 and limiting coolant velocity of 2.0 m/s from the steady-state performance analysis. As the result of the linear stability analysis, it has turned out that the STAR-LM natural circulation system would be stable even with gas injection. In addition, through the parametric study, it has been found that the thermal inertia effects of solid structures such as fuel rod and heat exchanger tube should be considered in the stability analysis model. The results of this study will be a part of the optimized stable design of the gas-injection enhanced natural circulation of STAR-LM with substantially improved power level and economical competitiveness. Furthermore, combined with the parametric study, this research could contribute a guideline for the design of other similar heavy-liquid-metal-cooled natural circulation systems with gas injection.

Laser spark distribution and ignition system

DOEpatents

Woodruff, Steven [Morgantown, WV; McIntyre, Dustin L [Morgantown, WV

2008-09-02

A laser spark distribution and ignition system that reduces the high power optical requirements for use in a laser ignition and distribution system allowing for the use of optical fibers for delivering the low peak energy pumping pulses to a laser amplifier or laser oscillator. An optical distributor distributes and delivers optical pumping energy from an optical pumping source to multiple combustion chambers incorporating laser oscillators or laser amplifiers for inducing a laser spark within a combustion chamber. The optical distributor preferably includes a single rotating mirror or lens which deflects the optical pumping energy from the axis of rotation and into a plurality of distinct optical fibers each connected to a respective laser media or amplifier coupled to an associated combustion chamber. The laser spark generators preferably produce a high peak power laser spark, from a single low power pulse. The laser spark distribution and ignition system has application in natural gas fueled reciprocating engines, turbine combustors, explosives and laser induced breakdown spectroscopy diagnostic sensors.

Excimer laser system Profile-500

NASA Astrophysics Data System (ADS)

Atejev, V. V.; Bukreyev, V. S.; Vartapetov, Serge K.; Semenov, A. D.; Sugrobov, V. A.; Turin, V. S.; Fedorov, Sergei N.

1999-07-01

The description of ophthalmological excimer laser system 'PROFILE-500' for photorefractive and physiotherapeutic keratectomy is presented. Excimer Laser Systems 'PROFILE- 500' are optical system that use ArF excimer lasers to perform photorefractive keratectomy or LASIK; surgical procedures used to correct myopia, hyperopia and astigmatism.

Imaging nanomaterials in vitro and in vivo by exploring their intrinsic nonlinear optical signals

NASA Astrophysics Data System (ADS)

Tong, Ling

The extension of nanotechnology to biomedical system creates a new and fast developing field, nanomedicine. A wide range of nanoparticles has been developed as imaging agents or drug carriers. However, the translation of nanomedicines to a clinical setting has been slowed down due to a limited fundamental understanding of the nano-bio interaction. My thesis work describes the efforts in imaging the behavior of nanomaterials in live cells and animals by exploring the nonlinear optical properties. The first part of my thesis focuses on study of metallic and semiconducting nanoparticles in biological environment using their nonlinear optical signals. In chapter 2, systemic circulation of PEGylated gold nanorods (GNRs) is visualized by intravital two-photon luminescence (TPL) imaging. A biphasic clearance is demonstrated with branched PEG showing longer circulation. Following clearance, cellular biodistribution of GNRs in organs is mapped by TPL imaging. GNRs accumulate in macrophages in liver and spleen (Langmuir, 2009, 25, 12454-12459). In chapter 3, a bright three-photon luminescence is discovered from Au-Ag alloyed nanostructure by excitation with a femtosecond laser at 1290 nm, which enables bio-imaging with negligible photothermal toxicity and tissue autofluorescence (Angew Chemie, 2010, 49, 3485-3488, inside cover story). In chapter 4, a new contrast is invented for label-free, real-time imaging of single-walled carbon nanotubes (SWNTs) by pump-probe microscopy. At pump/probe wavelength of 707 and 885 nm, semiconducting and metallic SWNTs (S-SWNTs and M-SWNTs) exhibit intense stimulated emission and absorption signals, which allow us to monitor the intracellular trafficking, distribution in tissues, and systemic circulation in vivo with single-nanotube sensitivity and sub-micron resolution. The second part presents label-free imaging of nanomedicines in live cells by coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS) microscopy. First, receptor-medicated endocytosis is visualized with a polymeric nanoparticle-based CARS probe (J. Phys. Chem. B, 2007, 111, 9980-9985). Second, the cellular drug delivery mechanism by poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) is reexamined by CARS microscopy and new discoveries that PLGA NPs are not readily taken up by cells and delivered the payload to cells by extracellular drug release and/or direct drug transfer to contacting cells are found (Mol. Pharmaceutics, 2009, 6, 190-201). Third, the sensitivity of SRS microscopy is improved to monitor liposomal drug delivery in live cells. The last part of my thesis depicts the applications of GNRs in diagnosis and phtotothermal therapy of tumor cells and activated macrophages. Photothermal effect of GNRs is monitored by TPL, confocal microscopy and biological assays. The formation of membrane blebs is observed. The subcellular mechanism is investigated to be a downstream effect of compromised membrane integrity, which permits influx of calcium and subsequent disruption of the actin network (Adv. Mater. 2007, 109, 3136-3141, cover story). In addition, cell death through necrosis or apoptosis is induced by controlling laser irradiation. The molecular mechanisms are determined as the loss of plasma membrane integrity for necrosis and intracellular perturbation with damage of mitochondria for apoptosis (Nanomedicine, 2009, 4, 265-276).

Updated laser safety & hazard analysis for the ARES laser system based on the 2007 ANSI Z136.1 standard.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Augustoni, Arnold L.

A laser safety and hazard analysis was performed for the temperature stabilized Big Sky Laser Technology (BSLT) laser central to the ARES system based on the 2007 version of the American National Standards Institutes (ANSI) Standard Z136.1, for Safe Use of Lasers and the 2005 version of the ANSI Standard Z136.6, for Safe Use of Lasers Outdoors. The ARES laser system is a Van/Truck based mobile platform, which is used to perform laser interaction experiments and tests at various national test sites.

Laser energy conversion

NASA Technical Reports Server (NTRS)

Jalufka, N. W.

1989-01-01

The conversion of laser energy to other, more useful, forms is an important element of any space power transmission system employing lasers. In general the user, at the receiving sight, will require the energy in a form other than laser radiation. In particular, conversion to rocket power and electricity are considered to be two major areas where one must consider various conversion techniques. Three systems (photovoltaic cells, MHD generators, and gas turbines) have been identified as the laser-to-electricity conversion systems that appear to meet most of the criteria for a space-based system. The laser thruster also shows considerable promise as a space propulsion system. At this time one cannot predict which of the three laser-to-electric converters will be best suited to particular mission needs. All three systems have some particular advantages, as well as disadvantages. It would be prudent to continue research on all three systems, as well as the laser rocket thruster. Research on novel energy conversion systems, such as the optical rectenna and the reverse free-electron laser, should continue due to their potential for high payoff.

Green high-power tunable external-cavity GaN diode laser at 515  nm.

PubMed

Chi, Mingjun; Jensen, Ole Bjarlin; Petersen, Paul Michael

2016-09-15

A 480 mW green tunable diode laser system is demonstrated for the first time to our knowledge. The laser system is based on a GaN broad-area diode laser and Littrow external-cavity feedback. The green laser system is operated in two modes by switching the polarization direction of the laser beam incident on the grating. When the laser beam is p-polarized, an output power of 50 mW with a tunable range of 9.2 nm is achieved. When the laser beam is s-polarized, an output power of 480 mW with a tunable range of 2.1 nm is obtained. This constitutes the highest output power from a tunable green diode laser system.

Laser beam monitoring system

DOEpatents

Weil, Bradley S.; Wetherington, Jr., Grady R.

1985-01-01

Laser beam monitoring systems include laser-transparent plates set at an angle to the laser beam passing therethrough and light sensor for detecting light reflected from an object on which the laser beam impinges.

Laser beam monitoring system

DOEpatents

Weil, B.S.; Wetherington, G.R. Jr.

Laser beam monitoring systems include laser-transparent plates set at an angle to the laser beam passing therethrough and light sensor for detecting light reflected from an object on which the laser beam impinges.

Research on Parallel Three Phase PWM Converters base on RTDS

NASA Astrophysics Data System (ADS)

Xia, Yan; Zou, Jianxiao; Li, Kai; Liu, Jingbo; Tian, Jun

2018-01-01

Converters parallel operation can increase capacity of the system, but it may lead to potential zero-sequence circulating current, so the control of circulating current was an important goal in the design of parallel inverters. In this paper, the Real Time Digital Simulator (RTDS) is used to model the converters parallel system in real time and study the circulating current restraining. The equivalent model of two parallel converters and zero-sequence circulating current(ZSCC) were established and analyzed, then a strategy using variable zero vector control was proposed to suppress the circulating current. For two parallel modular converters, hardware-in-the-loop(HIL) study based on RTDS and practical experiment were implemented, results prove that the proposed control strategy is feasible and effective.

Measurements Methods for the analysis of Nuclear Reactors Thermal Hydraulic in Water Scaled Facilities

NASA Astrophysics Data System (ADS)

Spaccapaniccia, C.; Planquart, P.; Buchlin, J. M. AB(; ), AC(; )

2018-01-01

The Belgian nuclear research institute (SCK•CEN) is developing MYRRHA. MYRRHA is a flexible fast spectrum research reactor, conceived as an accelerator driven system (ADS). The configuration of the primary loop is pool-type: the primary coolant and all the primary system components (core and heat exchangers) are contained within the reactor vessel, while the secondary fluid is circulating in the heat exchangers. The primary coolant is Lead Bismuth Eutectic (LBE). The recent nuclear accident of Fukushima in 2011 changed the requirements for the design of new reactors, which should include the possibility to remove the residual decay heat through passive primary and secondary systems, i.e. natural convection (NC). After the reactor shut down, in the unlucky event of propeller failures, the primary and secondary loops should be able to remove the decay heat in passive way (Natural Convection). The present study analyses the flow and the temperature distribution in the upper plenum by applying laser imaging techniques in a laboratory scaled water model. A parametric study is proposed to study stratification mitigation strategies by varying the geometry of the buffer tank simulating the upper plenum.

Physiological Responses to Thermal Stress and Exercise

NASA Astrophysics Data System (ADS)

Iyota, Hiroyuki; Ohya, Akira; Yamagata, Junko; Suzuki, Takashi; Miyagawa, Toshiaki; Kawabata, Takashi

The simple and noninvasive measuring methods of bioinstrumentation in humans is required for optimization of air conditioning and management of thermal environments, taking into consideration the individual specificity of the human body as well as the stress conditions affecting each. Changes in human blood circulation were induced with environmental factors such as heat, cold, exercise, mental stress, and so on. In this study, the physiological responses of human body to heat stress and exercise were investigated in the initial phase of the developmental research. We measured the body core and skin temperatures, skin blood flow, and pulse wave as the indices of the adaptation of the cardiovascular system. A laser Doppler skin blood flowmetry using an optical-sensor with a small portable data logger was employed for the measurement. These results reveal the heat-stress and exercise-induced circulatory responses, which are under the control of the sympathetic nerve system. Furthermore, it was suggested that the activity of the sympathetic nervous system could be evaluated from the signals of the pulse wave included in the signals derived from skin blood flow by means of heart rate variability assessments and detecting peak heights of velocity-plethysmogram.

Satellite Power Systems (SPS) laser studies. Volume 1: Laser environmental impact study

NASA Technical Reports Server (NTRS)

Beverly, R. E., III

1980-01-01

The environmental impact of space to Earth power transmission using space borne laser subsystems is emphasized. A laser system is defined, estimates of relevant efficiencies for laser power generation and atmospheric transmission are developed, and a comparison is made to a microwave system. Ancillary issues, such as laser beam spreading, safety and security, mass and volume estimates and technology growth are considered.

The ARGOS laser system: green light for ground layer adaptive optics at the LBT

NASA Astrophysics Data System (ADS)

Raab, Walfried; Rabien, Sebastian; Gässler, Wolfgang; Esposito, Simone; Barl, Lothar; Borelli, Jose; Daysenroth, Matthias; Gemperlein, Hans; Kulas, Martin; Ziegleder, Julian

2014-07-01

We report on the development of the laser system of ARGOS, the multiple laser guide star adaptive optics system for the Large Binocular Telescope (LBT). The system uses a total of six high powered, pulsed Nd:YAG lasers frequency-doubled to a wavelength of 532 nm to generate a set of three guide stars above each of the LBT telescopes. The position of each of the LGS constellations on sky as well as the relative position of the individual laser guide stars within this constellation is controlled by a set of steerable mirrors and a fast tip-tilt mirror within the laser system. The entire opto-mechanical system is housed in two hermetically sealed and thermally controlled enclosures on the SX and DX side of the LBT telescope. The laser beams are propagated through two refractive launch telescopes which focus the beams at an altitude of 12 km, creating a constellation of laser guide stars around a 4 arcminute diameter circle by means of Rayleigh scattering. In addition to the GLAO Rayleigh beacon system, ARGOS has also been designed for a possible future upgrade with a hybrid sodium laser - Rayleigh beacon combination, enabling diffraction limited operation. The ARGOS laser system was successfully installed at the LBT in April 2013. Extensive functional tests have been carried out and have verified the operation of the systems according to specifications. The alignment of the laser system with respect to the launch telescope was carried out during two more runs in June and October 2013, followed by the first propagation of laser light on sky in November 2013.

Control system for high power laser drilling workover and completion unit

DOEpatents

Zediker, Mark S; Makki, Siamak; Faircloth, Brian O; DeWitt, Ronald A; Allen, Erik C; Underwood, Lance D

2015-05-12

A control and monitoring system controls and monitors a high power laser system for performing high power laser operations. The control and monitoring system is configured to perform high power laser operation on, and in, remote and difficult to access locations.

Butterflies, Black swans and Dragon kings: How to use the Dynamical Systems Theory to build a "zoology" of mid-latitude circulation atmospheric extremes?

NASA Astrophysics Data System (ADS)

Faranda, D.; Yiou, P.; Alvarez-Castro, M. C. M.

2015-12-01

A combination of dynamical systems and statistical techniques allows for a robust assessment of the dynamical properties of the mid-latitude atmospheric circulation. Extremes at different spatial and time scales are not only associated to exceptionally intense weather structures (e.g. extra-tropical cyclones) but also to rapid changes of circulation regimes (thunderstorms, supercells) or the extreme persistence of weather structure (heat waves, cold spells). We will show how the dynamical systems theory of recurrence combined to the extreme value theory can take into account the spatial and temporal dependence structure of the mid-latitude circulation structures and provide information on the statistics of extreme events.

Optical diagnostics integrated with laser spark delivery system

DOEpatents

Yalin, Azer [Fort Collins, CO; Willson, Bryan [Fort Collins, CO; Defoort, Morgan [Fort Collins, CO; Joshi, Sachin [Fort Collins, CO; Reynolds, Adam [Fort Collins, CO

2008-09-02

A spark delivery system for generating a spark using a laser beam is provided, and includes a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. The laser delivery assembly further includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. Other embodiments use a fiber laser to generate a spark. Embodiments of the present invention may be used to create a spark in an engine. Yet other embodiments include collecting light from the spark or a flame resulting from the spark and conveying the light for diagnostics. Methods of using the spark delivery systems and diagnostic systems are provided.

Fiber laser coupled optical spark delivery system

DOEpatents

Yalin, Azer [Fort Collins, CO; Willson, Bryan [Fort Collins, CO; Defoort, Morgan [Fort Collins, CO; Joshi, Sachin [Fort Collins, CO; Reynolds, Adam [Fort Collins, CO

2008-03-04

A spark delivery system for generating a spark using a laser beam is provided, and includes a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. The laser delivery assembly further includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. Other embodiments use a fiber laser to generate a spark. Embodiments of the present invention may be used to create a spark in an engine. Yet other embodiments include collecting light from the spark or a flame resulting from the spark and conveying the light for diagnostics. Methods of using the spark delivery systems and diagnostic systems are provided.

Photothermal and photochemical effects of laser light absorption by indocyanine green (ICG)

NASA Astrophysics Data System (ADS)

Yaseen, Mohammad A.; Diagaradjane, Parmeswaran; Pikkula, Brian M.; Yu, Jie; Wong, Michael S.; Anvari, Bahman

2005-04-01

Indocyanine Green (ICG) is clinically used as a fluorescent dye for imaging purposes. Its rapid circulation kinetics and minimal toxicity has prompted investigation into ICG's utility as a photosentitizer for therapeutic applications. Traditionally, optically mediated tumor therapy has focused on photodynamic therapy, which employs a photochemical mechanism resulting from the absorption of low intensity CW laser light by localized photosensitizers such as Photofrin II, Benzoporphyrin Derivative (BPD), ICG. Treatment of cutaneous vascular malformations such as port-wine stains, on the other hand, is based on a photothermal mechanism resulting from the absorption of high intensity pulsed laser light by hemoglobin. In this study, we compared the effectiveness of combining photochemical and photothermal mechanisms during application of ICG in conjunction with laser irradiation with the intention that the combined approach may lead to a reduction in the threshold dose of pulsed laser light required to treat hypervascular malformations. The blood vessels in rabbit ears were used as an in vivo model for targeted vasculature. Irradiation of the ears with IR light (λ=785 nm, Δτ = 3 min, Io = 120 mW) was used to elicit photochemical damage, while photothermal damage was brought about using pulses from a ruby laser (λ=694 nm, τ = 3 ms) with different fluences. For the combined modality, photochemical damage was induced first and followed by photothermal irradiation. This modality was compared with photothermal irradiation alone. The effectiveness of each irradiation scheme was assessed using histopathological analysis. We present preliminary data that suggests that pretreatment with photodynamic therapy before photothermal coagulation results in more severe vascular damage with lower photothermal fluence levels. The results of this study provide the foundation work for further exploration of the therapeutic potentials of photochemical and photothermal effects during application of ICG in conjunction with laser irradiation.

A randomized placebo-blind study of the effect of low power laser on pain caused by irreversible pulpitis.

PubMed

Ramalho, Karen Müller; de Souza, Lárissa Marcondes Paladini; Tortamano, Isabel Peixoto; Adde, Carlos Alberto; Rocha, Rodney Garcia; de Paula Eduardo, Carlos

2016-12-01

This randomized placebo-blind study aimed to evaluate the effect of laser phototherapy (LPT) on pain caused by symptomatic irreversible pulpitis (SIP). Sixty patients diagnosed with SIP were randomly assigned to treatment groups (n = 15): G1 (control), G2 (laser placebo-sham irradiation), G3 (laser irradiation at 780 nm, 40 mW, 4 J/cm 2 ), and G4 (laser irradiation at 780 nm, 40 mW, 40 J/cm 2 ). Spontaneous pain was recorded using a VAS score before (T0), immediately after (T1), and 15 min after treatment (T2). Local anesthetics failure during emergency endodontic treatment was also assessed. There was no pain difference in T1 and T2 between the experimental laser groups (G3 and G4) and the placebo group (G2). The 4-J/cm 2 (G3) irradiation resulted in significant increase in the local anesthetics failure in lower jar teeth. This effect could be suggested as consequence of the LPT improvement in local circulation and vasodilatation that would result in the increase of local anesthetic agent absorption. The application of 780-nm diode laser irradiation, at 4 and 40 J/cm 2 , showed no effect in reducing the pain in SIP in comparison to the placebo group. The fluence of 4 J/cm 2 showed a negative effect in local anesthetics, resulting in significant increase of complimentary local anesthesia during emergency endodontic treatment. This work provides evidence of the consequence of LPT application on teeth with symptomatic irreversible pulpitis. LPT should be avoided in teeth with pain due to irreversible pulpitis.

New 223-nm excimer laser surgical system for photorefractive keratectomy

NASA Astrophysics Data System (ADS)

Bagaev, Sergei N.; Razhev, Alexander M.; Zhupikov, Andrey A.

1999-02-01

The using of KrCl (223 nm) excimer laser in ophthalmic devices for Photorefractive Keratectomy (PRK) and phototherapeutic Keratectomy (PTK) is offered. The structure and functions of a new surgical UV ophthalmic laser systems Medilex using ArF (193 nm) or KrCl (223 nm) excimer laser for corneal surgery are presented. The systems Medilex with the new optical delivery system is used for photoablative reprofiling of the cornea to correct refraction errors (myopia, hyperopia and astigmatism) and to treat a corneal pathologies. The use of the 223 nanometer laser is proposed to have advantages over the 193 nanometer laser. The results of application of the ophthalmic excimer laser systems Medilex for treatment of myopia are presented.

A vision-based system for fast and accurate laser scanning in robot-assisted phonomicrosurgery.

PubMed

Dagnino, Giulio; Mattos, Leonardo S; Caldwell, Darwin G

2015-02-01

Surgical quality in phonomicrosurgery can be improved by open-loop laser control (e.g., high-speed scanning capabilities) with a robust and accurate closed-loop visual servoing systems. A new vision-based system for laser scanning control during robot-assisted phonomicrosurgery was developed and tested. Laser scanning was accomplished with a dual control strategy, which adds a vision-based trajectory correction phase to a fast open-loop laser controller. The system is designed to eliminate open-loop aiming errors caused by system calibration limitations and by the unpredictable topology of real targets. Evaluation of the new system was performed using CO(2) laser cutting trials on artificial targets and ex-vivo tissue. This system produced accuracy values corresponding to pixel resolution even when smoke created by the laser-target interaction clutters the camera view. In realistic test scenarios, trajectory following RMS errors were reduced by almost 80 % with respect to open-loop system performances, reaching mean error values around 30 μ m and maximum observed errors in the order of 60 μ m. A new vision-based laser microsurgical control system was shown to be effective and promising with significant positive potential impact on the safety and quality of laser microsurgeries.

SU-E-T-99: Design and Development of Isocenter Parameter System for CT Simulation Laser Based On DICOM RT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, G

2014-06-01

Purpose: In order to receive DICOM files from treatment planning system and generate patient isocenter positioning parameter file for CT laser system automatically, this paper presents a method for communication with treatment planning system and calculation of isocenter parameter for each radiation field. Methods: Coordinate transformation and laser positioning file formats were analyzed, isocenter parameter was calculated via data from DICOM CT Data and DICOM RTPLAN file. An in-house software-DicomGenie was developed based on the object-oriented program platform-Qt with DCMTK SDK (Germany OFFIS company DICOM SDK) . DicomGenie was tested for accuracy using Philips CT simulation plan system (Tumor LOC,more » Philips) and A2J CT positioning laser system (Thorigny Sur Marne, France). Results: DicomGenie successfully established DICOM communication between treatment planning system, DICOM files were received by DicomGenie and patient laser isocenter information was generated accurately. Patient laser parameter data files can be used for for CT laser system directly. Conclusion: In-house software DicomGenie received and extracted DICOM data, isocenter laser positioning data files were created by DicomGenie and can be use for A2J laser positioning system.« less

A 1J LD pumped Nd:YAG pulsed laser system

NASA Astrophysics Data System (ADS)

Yi, Xue-bin; Wang, Bin; Yang, Feng; Li, Jing; Liu, Ya-Ping; Li, Hui-Jun; Wang, Yu; Chen, Ren

2017-11-01

A 1J LD pumped Nd;YAG pulsed laser was designed. The laser uses an oscillation and two-staged amplification structure, and applies diode bar integrated array as side-pump. The TEC temperature control device combing liquid cooling system is organized to control the temperature of the laser system. This study also analyzed the theoretical threshold of working material, the effect of thermal lens and the basic principle of laser amplification. The results showed that the laser system can achieve 1J, 25Hz pulse laser output, and the laser pulse can be output at two width: 6-7ns and 10ns, respectively, and the original beam angle is 1.2mrad. The laser system is characterized by small size, light weight, as well as good stability, which make it being applied in varied fields such as photovoltaic radar platform and etc

The laser and optical system for the RIBF-PALIS experiment

NASA Astrophysics Data System (ADS)

Sonoda, T.; Iimura, H.; Reponen, M.; Wada, M.; Katayama, I.; Sonnenschein, V.; Takamatsu, T.; Tomita, H.; Kojima, T. M.

2018-01-01

This paper describes the laser and optical system for the Parasitic radioactive isotope (RI) beam production by Laser Ion-Source (PALIS) in the RIKEN fragment separator facility. This system requires an optical path length of 70 m for transporting the laser beam from the laser light source to the place for resonance ionization. To accomplish this, we designed and implemented a simple optical system consisting of several mirrors equipped with compact stepping motor actuators, lenses, beam spot screens and network cameras. The system enables multi-step laser resonance ionization in the gas cell and gas jet via overlap with a diameter of a few millimeters, between the laser photons and atomic beam. Despite such a long transport distance, we achieved a transport efficiency for the UV laser beam of about 50%. We also confirmed that the position stability of the laser beam stays within a permissible range for dedicated resonance ionization experiments.

Development of Laser-Mediated Nanodroplet Real-Time PCR on Circulating Tumor Cells (CTC) by Microfilter Platform

DTIC Science & Technology

2015-06-01

DNA hybridization using fluorescence,”   Biopolymers 95(7), 472–486 (2011). 26. J.-L. Mergny and L. Lacroix,  “Analysis of thermal melting curves...Microfilter Platform PRINCIPAL INVESTIGATOR: Gregory W. Faris, Ph.D. CONTRACTING ORGANIZATION : SRI International Menlo Park, CA 94025 REPORT DATE...Ph.D. 5e. TASK NUMBER E-Mail: ! ! 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) SRI International AND ADDRESS(ES) 8

Heparin-coated extracorporeal circulation systems in heart surgery.

PubMed

Tagarakis, Georgios I; Tsilimingas, Nikolaos B

2009-11-01

Despite the progress accomplished in the field of off-pump heart surgery, the vast majority of cardiac operations are still performed with the use of extracorporeal circulation, otherwise known as "heart-lung machine." This valuable tool, however, is connected with various complications, partly deriving from the application of intravenous heparin, necessary for the extracorporeal circuits to function. In order to deal with these complications, which among others include postoperative hemorrhage and systemic inflammatory response, several extracorporeal circulation systems, which contain a heparin-coating on their blood-contacting surfaces, have been developed with patents. The philosophy behind the creation of these systems is that with the controlled absorption and interaction of this heparin with the blood elements, adequate intraoperative anticoagulation with lower doses of systemic heparin and fewer systemic complications can be achieved. The idea of the use of heparin coatings has also been applied in other settings, such as in renal dialysis catheters, ECMO (extracorporeal membrane oxygenation), MECC (minimized extracorporeal circulation) and left ventricle assist devices.

Laser safety and hazard analysis for the temperature stabilized BSLT ARES laser system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Augustoni, Arnold L.

A laser safety and hazard analysis was performed for the temperature stabilized Big Sky Laser Technology (BSLT) laser central to the ARES system based on the 2000 version of the American National Standards Institute's (ANSI) Standard Z136.1, for Safe Use of Lasers and the 2000 version of the ANSI Standard Z136.6, for Safe Use of Lasers Outdoors. As a result of temperature stabilization of the BSLT laser the operating parameters of the laser had changed requiring a hazard analysis based on the new operating conditions. The ARES laser system is a Van/Truck based mobile platform, which is used to performmore » laser interaction experiments and tests at various national test sites.« less

Development of a low-cost multiple diode PIV laser for high-speed flow visualization

NASA Astrophysics Data System (ADS)

Bhakta, Raj; Hargather, Michael

2017-11-01

Particle imaging velocimetry (PIV) is an optical visualization technique that typically incorporates a single high-powered laser to illuminate seeded particles in a fluid flow. Standard PIV lasers are extremely costly and have low frequencies that severely limit its capability in high speed, time-resolved imaging. The development of a multiple diode laser system consisting of continuous lasers allows for flexible high-speed imaging with a wider range of test parameters. The developed laser system was fabricated with off-the-shelf parts for approximately 500. A series of experimental tests were conducted to compare the laser apparatus to a standard Nd:YAG double-pulsed PIV laser. Steady and unsteady flows were processed to compare the two systems and validate the accuracy of the multiple laser design. PIV results indicate good correlation between the two laser systems and verifies the construction of a precise laser instrument. The key technical obstacle to this approach was laser calibration and positioning which will be discussed. HDTRA1-14-1-0070.

Laser beam distribution system for the HiLASE Center

NASA Astrophysics Data System (ADS)

Macúchová, Karolina; Heřmánek, Jan; Kaufman, Jan; Muresan, Mihai-George; Růžička, Jan; Řeháková, Martina; Divoký, Martin; Švandrlík, Luděk.; Mocek, Tomáś

2017-12-01

We report recent progress in design and testing of a distribution system for high-power laser beam delivery developed within the HiLASE project of the IOP in the Czech Republic. Laser beam distribution system is a technical system allowing safe and precise distribution of different laser beams from laboratories to several experimental stations. The unique nature of HiLASE lasers requires new approach, which makes design of the distribution system a state-of-the-art challenge.

Analysis of pollutant chemistry in combustion by in situ pulsed photoacoustic laser diagnostics

NASA Astrophysics Data System (ADS)

Stenberg, Jari; Hernberg, Rolf; Vattulainen, Juha

1995-12-01

A technique for gas analysis based on pulsed-laser-induced photoacoustic spectroscopy in the UV and the visible is presented. The laser-based technique and the associated analysis probe have been developed for the analysis of pollutant chemistry in fluidized beds and other combustion environments with limited or no optical access. The photoacoustic-absorption spectrum of the analyzed gas is measured in a test cell located at the end of a tubular probe. This test cell is subject to the prevailing temperature and pressure in the combustion process. The instrument response has been calibrated for N2O, NO, NO2, NH3, SO2, and H2 S at atmospheric pressure between 20 and 910 deg C. The response of the probe was found to increase with pressure for N2O, NO, NH 3, and NO2 up to 1.2 MPa pressure. The method and the probe have been used for detection and ranging of gas concentrations in a premixed methane flame. Some preliminary tests in a large 12-MW circulating bed boiler have also been done.

Control electronics for a multi-laser/multi-detector scanning system

NASA Technical Reports Server (NTRS)

Kennedy, W.

1980-01-01

The Mars Rover Laser Scanning system uses a precision laser pointing mechanism, a photodetector array, and the concept of triangulation to perform three dimensional scene analysis. The system is used for real time terrain sensing and vision. The Multi-Laser/Multi-Detector laser scanning system is controlled by a digital device called the ML/MD controller. A next generation laser scanning system, based on the Level 2 controller, is microprocessor based. The new controller capabilities far exceed those of the ML/MD device. The first draft circuit details and general software structure are presented.

Regulation of diet-induced adipose tissue and systemic inflammation by salicylates and pioglitazone.

PubMed

Kim, Myung-Sunny; Yamamoto, Yasuhiko; Kim, Kyungjin; Kamei, Nozomu; Shimada, Takeshi; Liu, Libin; Moore, Kristin; Woo, Ju Rang; Shoelson, Steven E; Lee, Jongsoon

2013-01-01

It is increasingly accepted that chronic inflammation participates in obesity-induced insulin resistance and type 2 diabetes (T2D). Salicylates and thiazolidinediones (TZDs) both have anti-inflammatory and anti-hyperglycemic properties. The present study compared the effects of these drugs on obesity-induced inflammation in adipose tissue (AT) and AT macrophages (ATMs), as well as the metabolic and immunological phenotypes of the animal models. Both drugs improved high fat diet (HFD)-induced insulin resistance. However, salicylates did not affect AT and ATM inflammation, whereas Pioglitazone improved these parameters. Interestingly, HFD and the drug treatments all modulated systemic inflammation as assessed by changes in circulating immune cell numbers and activation states. HFD increased the numbers of circulating white blood cells, neutrophils, and a pro-inflammatory monocyte subpopulation (Ly6C(hi)), whereas salicylates and Pioglitazone normalized these cell numbers. The drug treatments also decreased circulating lymphocyte numbers. These data suggest that obesity induces systemic inflammation by regulating circulating immune cell phenotypes and that anti-diabetic interventions suppress systemic inflammation by normalizing circulating immune phenotypes.

Plausible Effect of Weather on Atlantic Meridional Overturning Circulation with a Coupled General Circulation Model

NASA Astrophysics Data System (ADS)

Liu, Zedong; Wan, Xiuquan

2018-04-01

The Atlantic meridional overturning circulation (AMOC) is a vital component of the global ocean circulation and the heat engine of the climate system. Through the use of a coupled general circulation model, this study examines the role of synoptic systems on the AMOC and presents evidence that internally generated high-frequency, synoptic-scale weather variability in the atmosphere could play a significant role in maintaining the overall strength and variability of the AMOC, thereby affecting climate variability and change. Results of a novel coupling technique show that the strength and variability of the AMOC are greatly reduced once the synoptic weather variability is suppressed in the coupled model. The strength and variability of the AMOC are closely linked to deep convection events at high latitudes, which could be strongly affected by the weather variability. Our results imply that synoptic weather systems are important in driving the AMOC and its variability. Thus, interactions between atmospheric weather variability and AMOC may be an important feedback mechanism of the global climate system and need to be taken into consideration in future climate change studies.

Investigations of a Dual Seeded 1178 nm Raman Laser System

DTIC Science & Technology

2016-01-14

20 W. Because of the linewidth broadening, a co- pumped second Stokes Raman laser system is not useful for the sodium guidestar laser application... pumped second Stokes Raman laser system is not useful for the sodium guidestar laser application which requires narrow linewidth. Keywords: Raman...optical efficiency of 52% when pumped with a linearly polarized 1120 nm fiber laser10,11. Because of the all-polarization maintaining configuration, a

Study of a plate-electrode XeCl laser with a pulse repetition rate up to 5 kHz

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voevodin, Denis D; Vysotskii, Andrei V; Lazhintsev, Boris V

2012-11-30

The results of the study of a repetitively pulsed XeCl laser with a high rate of pulse repetition and the electrode assembly based on a multi-section discharge gap with inductance-capacitance stabilisation of the discharge are presented. The multi-section discharge gap is formed by 25 pairs of anode - cathode plates. The discharge formed in the interelectrode gap had the dimensions 250 Multiplication-Sign 12 Multiplication-Sign 2 mm. The studies were performed using the HCl - Xe - Ne laser mixture at the total pressure up to 3.5 atm. The limit value of the radiation pulse repetition rate was equal to 5more » kHz. The meansquare deviation of the pulse energy increased from 0.8 % to 1.6 % in the range of repetition rates from 1 to 4.5 kHz and did not exceed 2.4 % at the frequency 5 kHz. The maximal energy of the laser pulse and the efficiency coefficient were equal to 7.9 mJ and 1.6 %, respectively. The maximal power of laser radiation (31 W) was obtained at the repetition rate 5 kHz. A new technique of measuring the gas flow velocity in the interelectrode gap is proposed. The velocity of gas circulation at the maximal pressure of the mixture did not exceed 18 m s{sup -1}. Optical inhomogeneities were observed, caused by a high concentration of electrons in the discharge plasma, by the acoustic wave, arising in the discharge gap, and by the heating of the gas in the discharge. (lasers)« less

Oxidative Burst of Circulating Neutrophils Following Traumatic Brain Injury in Human

PubMed Central

Liao, Yiliu; Liu, Peng; Guo, Fangyuan; Zhang, Zhi-Yuan; Zhang, Zhiren

2013-01-01

Besides secondary injury at the lesional site, Traumatic brain injury (TBI) can cause a systemic inflammatory response, which may cause damage to initially unaffected organs and potentially further exacerbate the original injury. Here we investigated plasma levels of important inflammatory mediators, oxidative activity of circulating leukocytes, particularly focusing on neutrophils, from TBI subjects and control subjects with general trauma from 6 hours to 2 weeks following injury, comparing with values from uninjured subjects. We observed increased plasma level of inflammatory cytokines/molecules TNF-α, IL-6 and CRP, dramatically increased circulating leukocyte counts and elevated expression of TNF-α and iNOS in circulating leukocytes from TBI patients, which suggests a systemic inflammatory response following TBI. Our data further showed increased free radical production in leukocyte homogenates and elevated expression of key oxidative enzymes iNOS, COX-2 and NADPH oxidase (gp91phox) in circulating leukocytes, indicating an intense induction of oxidative burst following TBI, which is significantly greater than that in control subjects with general trauma. Furthermore, flow cytometry assay proved neutrophils as the largest population in circulation after TBI and showed significantly up-regulated oxidative activity and suppressed phagocytosis rate for circulating neutrophils following brain trauma. It suggests that the highly activated neutrophils might play an important role in the secondary damage, even outside the injured brain. Taken together, the potent systemic inflammatory response induced by TBI, especially the intensively increase oxidative activity of circulating leukocytes, mainly neutrophils, may lead to a systemic damage, dysfunction/damage of bystander tissues/organs and even further exacerbate secondary local damage. Controlling these pathophysiological processes may be a promising therapeutic strategy and will protect unaffected organs and the injured brain from the secondary damage. PMID:23894384

Ground-Based and Space-Based Laser Beam Power Applications

NASA Technical Reports Server (NTRS)

Bozek, John M.

1995-01-01

A space power system based on laser beam power is sized to reduce mass, increase operational capabilities, and reduce complexity. The advantages of laser systems over solar-based systems are compared as a function of application. Power produced from the conversion of a laser beam that has been generated on the Earth's surface and beamed into cislunar space resulted in decreased round-trip time for Earth satellite electric propulsion tugs and a substantial landed mass savings for a lunar surface mission. The mass of a space-based laser system (generator in space and receiver near user) that beams down to an extraterrestrial airplane, orbiting spacecraft, surface outpost, or rover is calculated and compared to a solar system. In general, the advantage of low mass for these space-based laser systems is limited to high solar eclipse time missions at distances inside Jupiter. The power system mass is less in a continuously moving Mars rover or surface outpost using space-based laser technology than in a comparable solar-based power system, but only during dust storm conditions. Even at large distances for the Sun, the user-site portion of a space-based laser power system (e.g., the laser receiver component) is substantially less massive than a solar-based system with requisite on-board electrochemical energy storage.

Solar-powered cooling system

DOEpatents

Farmer, Joseph C

2013-12-24

A solar-powered adsorption-desorption refrigeration and air conditioning system uses nanostructural materials made of high specific surface area adsorption aerogel as the adsorptive media. Refrigerant molecules are adsorbed on the high surface area of the nanostructural material. A circulation system circulates refrigerant from the nanostructural material to a cooling unit.

From Dye Laser Factory to Portable Semiconductor Laser: Four Generations of Sodium Guide Star Lasers for Adaptive Optics in Astronomy and Space Situational Awareness

NASA Astrophysics Data System (ADS)

d'Orgeville, C.; Fetzer, G.

This presentation recalls the history of sodium guide star laser systems used in astronomy and space situational awareness adaptive optics, analysing the impact that sodium laser technology evolution has had on routine telescope operations. While it would not be practical to describe every single sodium guide star laser system developed to date, it is possible to characterize their evolution in broad technology terms. The first generation of sodium lasers used dye laser technology to create the first sodium laser guide stars in Hawaii, California, and Spain in the late 1980's and 1990's. These experimental systems were turned into the first laser guide star facilities to equip medium-to-large diameter adaptive optics telescopes, opening a new era of LGS AO-enabled diffraction-limited imaging from the ground. Although they produced exciting scientific results, these laser guide star facilities were large, power-hungry and messy. In the USA, a second-generation of sodium lasers was developed in the 2000's that used cleaner, yet still large and complex, solid-state laser technology. These are the systems in routine operation at the 8-10m class astronomical telescopes and 4m-class satellite imaging facilities today. Meanwhile in Europe, a third generation of sodium lasers was being developed using inherently compact and efficient fiber laser technology, and resulting in the only commercially available sodium guide star laser system to date. Fiber-based sodium lasers will be deployed at two astronomical telescopes and at least one space debris tracking station this year. Although highly promising, these systems remain significantly expensive and they have yet to demonstrate high performance in the field. We are proposing to develop a fourth generation of sodium lasers: based on semiconductor technology, these lasers could provide the final solution to the problem of sodium laser guide star adaptive optics for all astronomy and space situational awareness applications.

Experimental and analytical study of stability characteristics of natural circulation boiling water reactors during startup transient

NASA Astrophysics Data System (ADS)

Woo, Kyoungsuk

Two-phase natural circulation loops are unstable at low pressure operating conditions. New reactor design relying on natural circulation for both normal and abnormal core cooling is susceptible to different types of flow instabilities. In contrast to forced circulation boiling water reactor (BWR), natural circulation BWR is started up without recirculation pumps. The tall chimney placed on the top of the core makes the system susceptible to flashing during low pressure start-up. In addition, the considerable saturation temperature variation may induce complicated dynamic behavior driven by thermal non-equilibrium between the liquid and steam. The thermal-hydraulic problems in two-phase natural circulation systems at low pressure and low power conditions are investigated through experimental methods. Fuel heat conduction, neutron kinetics, flow kinematics, energetics and dynamics that govern the flow behavior at low pressure, are formulated. A dimensionless analysis is introduced to obtain governing dimensionless groups which are groundwork of the system scaling. Based on the robust scaling method and start-up procedures of a typical natural circulation BWR, the simulation strategies for the transient with and without void reactivity feedback is developed. Three different heat-up rates are applied to the transient simulations to study characteristics of the stability during the start-up. Reducing heat-up rate leads to increase in the period of flashing-induced density wave oscillation and decrease in the system pressurization rate. However, reducing the heat-up rate is unable to completely prevent flashing-induced oscillations. Five characteristic regions of stability are discovered at low pressure conditions. They are stable single-phase, flashing near the separator, intermittent oscillation, sinusoidal oscillation and low subcooling stable regions. Stability maps were acquired for system pressures ranging 100 kPa to 400 kPa. According to experimental investigation, the flow becomes stable below a certain heat flux regardless of the inlet subcooling at the core and system pressure. At higher heat flux, unstable phenomena were indentified within a certain range of inlet subcooling. The unstable region diminishes as the system pressure increases. In natural circulation BWRs, the significant gravitational pressure drop over the tall chimney section induces a Type-I instability. The Type-I instability becomes especially important during low power and pressure conditions during reactor start-up. Under these circumstances the effect of pressure variations on the saturation enthalpy becomes significant. An experimental study shows that the flashing phenomenon in the adiabatic chimney section is dominant during the start-up of a natural circulation BWR. Since flashing occurs outside the core, nuclear feedback effects on the stability are small. Furthermore, the thermal-hydraulic oscillation period is much longer than power fluctuation period caused by void reactivity feedback. In the natural circulation system increasing the inlet restriction reduces the natural circulation flow rate, shifting the unstable region to higher inlet subcooling.

Circulatory response and autonomic nervous activity during gum chewing.

PubMed

Hasegawa, Yoko; Sakagami, Joe; Ono, Takahiro; Hori, Kazuhiro; Zhang, Min; Maeda, Yoshinobu

2009-08-01

Mastication has been proven to enhance the systemic circulation, with circulatory responses seeming to be largely regulated by autonomic nervous activity via a more complex regulatory system than those of other activities. However, few studies have examined the relationships between changes in autonomic nervous activity and the systemic circulation that are induced by masticatory movement. We investigated changes in the systemic circulation and autonomic nervous activity during gum chewing to clarify the influence of mastication. Electrocardiograms, arterial blood pressure, and masseter electromyograms were taken while chewing gum continuously as indicators of systemic circulation in 10 healthy subjects with normal dentition. Cardiac sympathetic activity and vagus nervous activity, as well as vasomotor sympathetic nervous activity, were evaluated by fluctuation analysis of heart rate and blood pressure. Repeated analysis of variance and multiple comparisons were performed to determine chronological changes in each indicator during gum chewing. Gum chewing increased the heart rate and the mean arterial pressure. Although cardiac sympathetic activity and vagus nervous activity showed significant changes, vasomotor sympathetic nervous activity did not. These results suggest that changes in the autonomic nervous activity of the heart are mainly involved in the enhancement of systemic circulation with gum chewing. This explains some characteristics of autonomic nervous regulation in masticatory movement.

Recent results on modelling the spatial and temporal structure of the Earth's gravity field.

PubMed

Moore, P; Zhang, Q; Alothman, A

2006-04-15

The Earth's gravity field plays a central role in sea-level change. In the simplest application a precise gravity field will enable oceanographers to capitalize fully on the altimetric datasets collected over the past decade or more by providing a geoid from which absolute sea-level topography can be recovered. However, the concept of a static gravity field is now redundant as we can observe temporal variability in the geoid due to mass redistribution in or on the total Earth system. Temporal variability, associated with interactions between the land, oceans and atmosphere, can be investigated through mass redistributions with, for example, flow of water from the land being balanced by an increase in ocean mass. Furthermore, as ocean transport is an important contributor to the mass redistribution the time varying gravity field can also be used to validate Global Ocean Circulation models. This paper will review the recent history of static and temporal gravity field recovery, from the 1980s to the present day. In particular, mention will be made of the role of satellite laser ranging and other space tracking techniques, satellite altimetry and in situ gravity which formed the basis of gravity field determination until the last few years. With the launch of Challenging Microsatellite Payload and Gravity and Circulation Experiment (GRACE) our knowledge of the spatial distribution of the Earth's gravity field is taking a leap forward. Furthermore, GRACE is now providing insight into temporal variability through 'monthly' gravity field solutions. Prior to this data we relied on satellite tracking, Global Positioning System and geophysical models to give us insight into the temporal variability. We will consider results from these methodologies and compare them to preliminary results from the GRACE mission.

Children's Urinary Environmental Carbon Load. A Novel Marker Reflecting Residential Ambient Air Pollution Exposure?

PubMed

Saenen, Nelly D; Bové, Hannelore; Steuwe, Christian; Roeffaers, Maarten B J; Provost, Eline B; Lefebvre, Wouter; Vanpoucke, Charlotte; Ameloot, Marcel; Nawrot, Tim S

2017-10-01

Ambient air pollution, including black carbon, entails a serious public health risk because of its carcinogenic potential and as climate pollutant. To date, an internal exposure marker for black carbon particles that have cleared from the systemic circulation into the urine does not exist. To develop and validate a novel method to measure black carbon particles in a label-free way in urine. We detected urinary carbon load in 289 children (aged 9-12 yr) using white-light generation under femtosecond pulsed laser illumination. Children's residential black carbon concentrations were estimated based on a high-resolution spatial temporal interpolation method. We were able to detect urinary black carbon in all children, with an overall average (SD) of 98.2 × 10 5 (29.8 × 10 5 ) particles/ml. The urinary black carbon load was positively associated with medium-term to chronic (1 mo or more) residential black carbon exposure: +5.33 × 10 5 particles/ml higher carbon load (95% confidence interval, 1.56 × 10 5 to 9.10 × 10 5 particles/ml) for an interquartile range increment in annual residential black carbon exposure. Consistently, children who lived closer to a major road (≤160 m) had higher urinary black carbon load (6.93 × 10 5 particles/ml; 95% confidence interval, 0.77 × 10 5 to 13.1 × 10 5 ). Urinary black carbon mirrors the accumulation of medium-term to chronic exposure to combustion-related air pollution. This specific biomarker reflects internal systemic black carbon particles cleared from the circulation into the urine, allowing investigators to unravel the complexity of particulate-related health effects.

High-power direct-diode laser successes

NASA Astrophysics Data System (ADS)

Haake, John M.; Zediker, Mark S.

2004-06-01

Direct diode laser will become much more prevalent in the solar system of manufacturing due to their high efficiency, small portable size, unique beam profiles, and low ownership costs. There has been many novel applications described for high power direct diode laser [HPDDL] systems but few have been implemented in extreme production environments due to diode and diode system reliability. We discuss several novel applications in which the HPDDL have been implemented and proven reliable and cost-effective in production environments. These applications are laser hardening/surface modification, laser wire feed welding and laser paint stripping. Each of these applications uniquely tests the direct diode laser systems capabilities and confirms their reliability in production environments. A comparison of the advantages direct diode laser versus traditional industrial lasers such as CO2 and Nd:YAG and non-laser technologies such a RF induction, and MIG welders for each of these production applications is presented.

Heterodyne laser instantaneous frequency measurement system

DOEpatents

Wyeth, Richard W.; Johnson, Michael A.; Globig, Michael A.

1989-01-01

A heterodyne laser instantaneous frequency measurement system is disclosed. The system utilizes heterodyning of a pulsed laser beam with a continuous wave laser beam to form a beat signal. The beat signal is processed by a controller or computer which determines both the average frequency of the laser pulse and any changes or chirp of th frequency during the pulse.

Elite Circulation and the Convertibility of Knowledge: Comparing Different Types and Forms of Knowledge and Degrees of Elite Circulation in Europe

ERIC Educational Resources Information Center

Mangset, Marte

2017-01-01

According to classical elite theory, increased circulation is related to increased integration which is thought to increase elites' power. Based on a comparative analysis of some European countries' elite education systems, recruitment to elite positions and degrees of circulation--with a specific focus on administrative elites--this article…

Laser system development for gravitational-wave interferometry in space

NASA Astrophysics Data System (ADS)

Numata, Kenji; Yu, Anthony W.; Camp, Jordan B.; Krainak, Michael A.

2018-02-01

A highly stable and robust laser system is a key component of the space-based Laser Interferometer Space Antenna (LISA) mission, which is designed to detect gravitational waves from various astronomical sources. The baseline architecture for the LISA laser consists of a low-power, low-noise Nd:YAG non-planar ring oscillator (NPRO) followed by a diode-pumped Yb-fiber amplifier with 2 W output. We are developing such laser system at the NASA Goddard Space Flight Center (GSFC), as well as investigating other laser options. In this paper, we will describe our progress to date and plans to demonstrate a technology readiness level (TRL) 6 LISA laser system.

Comparisons of selected laser beam power missions to conventionally powered missions

NASA Technical Reports Server (NTRS)

Bozek, John M.; Oleson, Steven R.; Landis, Geoffrey A.; Stavnes, Mark W.

1993-01-01

Earth-based laser sites beaming laser power to space assets have shown benefits over competing power system concepts for specific missions. Missions analyzed in this report that show benefits of laser beam power are low Earth orbit (LEO) to geosynchronous Earth orbit (GEO) transfer, LEO to low lunar orbit (LLO) cargo missions, and lunar-base power. Both laser- and solar-powered orbit-transfer vehicles (OTV's) make a 'tug' concept viable, which substantially reduces cumulative initial mass to LEO in comparison to chemical propulsion concepts. Lunar cargo missions utilizing laser electric propulsion from Earth-orbit to LLO show substantial mass saving to LEO over chemical propulsion systems. Lunar-base power system options were compared on a landed-mass basis. Photovoltaics with regenerative fuel cells, reactor-based systems, and laser-based systems were sized to meet a generic lunar-base power profile. A laser-based system begins to show landed mass benefits over reactor-based systems when proposed production facilities on the Moon require power levels greater than approximately 300 kWe. Benefit/cost ratios of laser power systems for an OTV, both to GEO and LLO, and for a lunar base were calculated to be greater than 1.

Circulating anti-double-stranded DNA antibody-secreting cells in patients with systemic lupus erythematosus: a novel biomarker for disease activity.

PubMed

Hanaoka, H; Okazaki, Y; Satoh, T; Kaneko, Y; Yasuoka, H; Seta, N; Kuwana, M

2012-10-01

Antibodies against double-stranded DNA (dsDNA) are widely used to diagnose systemic lupus erythematosus (SLE) and evaluate its activity in patients. This study was undertaken to examine the clinical utility of circulating anti-dsDNA antibody-secreting cells for evaluating SLE patients. Anti-dsDNA antibody-secreting cells quantified using an enzyme-linked immunospot assay were detected in the spleen, bone marrow and peripheral blood from MRL/lpr but not in control BALB/c mice. Circulating anti-dsDNA antibody-secreting cells were detected in 29 (22%) of 130 patients with SLE, but in none of 49 with non-SLE connective-tissue disease or 18 healthy controls. The presence of circulating anti-dsDNA antibody-secreting cells was associated with persistent proteinuria, high SLE disease activity index and systemic lupus activity measures, and a high serum anti-dsDNA antibody titre measured with an enzyme-linked immunosorbent assay. The positive predictive value for active disease was 48% for circulating anti-dsDNA antibody-secreting cells versus 17% for serum anti-dsDNA antibodies. A prospective cohort of patients with circulating anti-dsDNA antibodies and inactive SLE showed that the cumulative disease flare-free rate was significantly lower in patients with than without circulating anti-dsDNA antibody-secreting cells (p < 0.001). Circulating anti-dsDNA antibody-secreting cells are a useful biomarker for assessing disease activity in SLE patients.

Near-infrared light stimuli-responsive synergistic therapy nanoplatforms based on the coordination of tellurium-containing block polymer and cisplatin for cancer treatment.

PubMed

Li, Feng; Li, Tianyu; Cao, Wei; Wang, Lu; Xu, Huaping

2017-07-01

Cisplatin (CDDP) has received worldwide approval for clinical use in the past decades. However, its development in cancer chemotherapy was overshadowed by severe side effects and drug resistance. Herein, we developed a CDDP drug delivery system with high encapsulation efficiency and near-infrared light stimuli-responsive drug release properties based on the coordination of novel tellurium-containing block polymer (PEG-PUTe-PEG) and CDDP. The nanocarriers made from PEG-PUTe-PEG were loaded with CDDP and indocyanine green (ICG) simultaneously. The coordination chemistry between CDDP and tellurium guaranteed the nanocarrier a high stability in plasma and prolonged circulation time in vivo by reducing possible penetration of water molecule into the nanoparticles. Under the stimuli of a near-infrared laser, an amount of ROS can be generated by irradiation of ICG. The tellurium is easily oxidized by ROS because of the low electronegativity of tellurium. The CDDP could be rapidly released from the nanocarriers along with the oxidation of the tellurium at the tumor sites as the oxidized tellurium will weaken the coordination interaction with CDDP. In addition, the encapsulated ICG played a synergistic antitumor effect through photothermal effect with mild laser irradiation. The integrated strategy achieved higher antitumor efficacy and showed minimal side effects compared with the CDDP alone. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance calculation and simulation system of high energy laser weapon

NASA Astrophysics Data System (ADS)

Wang, Pei; Liu, Min; Su, Yu; Zhang, Ke

2014-12-01

High energy laser weapons are ready for some of today's most challenging military applications. Based on the analysis of the main tactical/technical index and combating process of high energy laser weapon, a performance calculation and simulation system of high energy laser weapon was established. Firstly, the index decomposition and workflow of high energy laser weapon was proposed. The entire system was composed of six parts, including classical target, platform of laser weapon, detect sensor, tracking and pointing control, laser atmosphere propagation and damage assessment module. Then, the index calculation modules were designed. Finally, anti-missile interception simulation was performed. The system can provide reference and basis for the analysis and evaluation of high energy laser weapon efficiency.

Comparative hazard evaluation of near-infrared diode lasers.

PubMed

Marshall, W J

1994-05-01

Hazard evaluation methods from various laser protection standards differ when applied to extended-source, near-infrared lasers. By way of example, various hazard analyses are applied to laser training systems, which incorporate diode lasers, specifically those that assist in training military or law enforcement personnel in the proper use of weapons by simulating actual firing by the substitution of a beam of near-infrared energy for bullets. A correct hazard evaluation of these lasers is necessary since simulators are designed to be directed toward personnel during normal use. The differences among laser standards are most apparent when determining the hazard class of a laser. Hazard classification is based on a comparison of the potential exposures with the maximum permissible exposures in the 1986 and 1993 versions of the American National Standard for the Safe Use of Lasers, Z136.1, and the accessible emission limits of the federal laser product performance standard. Necessary safety design features of a particular system depend on the hazard class. The ANSI Z136.1-1993 standard provides a simpler and more accurate hazard assessment of low-power, near-infrared, diode laser systems than the 1986 ANSI standard. Although a specific system is evaluated, the techniques described can be readily applied to other near-infrared lasers or laser training systems.

Optically-Based Diagnostics for Gas-Phase Laser Development

DTIC Science & Technology

2010-08-01

Laser (COIL), Electric Oxygen Iodine Laser (EOIL), Diode-Pumped Alkali Laser (DPAL), and Exciplex Alkali Laser (XPAL). The papers at this Symposium... exciplex -assisted absorption and laser-induced fluorescence, and multi-photon excitation of infrared atomic alkali transitions.11,12 In this paper... EXCIPLEX LASER SYSTEMS Proper review and discussion of the DPAL and XPAL laser systems can be found elsewhere,11,12 and in the paper by Carroll and

Phasing surface emitting diode laser outputs into a coherent laser beam

DOEpatents

Holzrichter, John F [Berkeley, CA

2006-10-10

A system for generating a powerful laser beam includes a first laser element and at least one additional laser element having a rear laser mirror, an output mirror that is 100% reflective at normal incidence and <5% reflective at an input beam angle, and laser material between the rear laser mirror and the output mirror. The system includes an injector, a reference laser beam source, an amplifier and phase conjugater, and a combiner.

Development of the Technologies for Stabilization Treatment of the Water of the Recycling Cooling Systems at Thermal Power Plants

NASA Astrophysics Data System (ADS)

Vlasov, S. M.; Chichirova, N. D.; Chichirov, A. A.; Vlasova, A. Yu.; Filimonova, A. A.; Prosvirnina, D. V.

2018-02-01

A turbine-condensate cooling system is one of the less stable and most hard-to-control systems of maintaining optimal water chemistry. A laboratory recycling cooling water test facility, UVO-0.3, was developed for physical simulation of innovative zero-discharge water chemistry conditions and improvement of technological flowcharts of stabilization treatment of the initial and circulating water of the recycling cooling systems at thermal power plants. Experiments were conducted in the UVO-0.3 facility to investigate the processes that occur in the recycling water supply system and master new technologies of stabilization of the initial and circulating water. It is shown that, when using untreated initial water, scaling cannot be prevented even under low concentration levels. The main reason for the activation of scale depositing is the desorption of carbon dioxide that results in alkalization of the circulating water and, as a consequence, a displacement of the chemical reaction equilibrium towards the formation of slightly soluble hardness ions. Some techniques, viz., liming and alkalization of the initial water and the by-pass treatment of the circulating water, are considered. New engineering solutions have been developed for reducing the amount of scale-forming substances in the initial and circulating water. The best results were obtained by pretreating the initial water with alkalizing agents and simultaneously bypassing and treating part of the circulating water. The obtained experimental data underlie the process flowcharts of stabilization treatment of the initial and circulating TPP water that ensure scale-free and noncorrosive operation and meet the corresponding environmental requirements. Under the bypassing, the specific rates of the agents and the residual hardness are reduced compared with the conventional pretreatment.

Formation of propagation invariant laser beams with anamorphic optical systems

NASA Astrophysics Data System (ADS)

Soskind, Y. G.

2015-03-01

Propagation invariant structured laser beams play an important role in several photonics applications. A majority of propagation invariant beams are usually produced in the form of laser modes emanating from stable laser cavities. This work shows that anamorphic optical systems can be effectively employed to transform input propagation invariant laser beams and produce a variety of alternative propagation invariant structured laser beam distributions with different shapes and phase structures. This work also presents several types of anamorphic lens systems suitable for transforming the input laser modes into a variety of structured propagation invariant beams. The transformations are applied to different laser mode types, including Hermite-Gaussian, Laguerre-Gaussian, and Ince-Gaussian field distributions. The influence of the relative azimuthal orientation between the input laser modes and the anamorphic optical systems on the resulting transformed propagation invariant beams is presented as well.

Lasant Materials for Blackbody-Pumped Lasers

NASA Technical Reports Server (NTRS)

Deyoung, R. J. (Editor); Chen, K. Y. (Editor)

1985-01-01

Blackbody-pumped solar lasers are proposed to convert sunlight into laser power to provide future space power and propulsion needs. There are two classes of blackbody-pumped lasers. The direct cavity-pumped system in which the lasant molecule is vibrationally excited by the absorption of blackbody radiation and laser, all within the blackbody cavity. The other system is the transfer blackbody-pumped laser in which an absorbing molecule is first excited within the blackbody cavity, then transferred into a laser cavity when an appropriate lasant molecule is mixed. Collisional transfer of vibrational excitation from the absorbing to the lasing molecule results in laser emission. A workshop was held at NASA Langley Research Center to investigate new lasant materials for both of these blackbody systems. Emphasis was placed on the physics of molecular systems which would be appropriate for blackbody-pumped lasers.

Laser Pyro System Standardization and Man Rating

NASA Technical Reports Server (NTRS)

Brown, Christopher W.

2004-01-01

This viewgraph presentation reviews an X-38 laser pyro system standardization system designed for a new manned rated program. The plans to approve this laser initiation system and preliminary ideas for this system are also provided.

Four generations of sodium guide star lasers for adaptive optics in astronomy and space situational awareness

NASA Astrophysics Data System (ADS)

d'Orgeville, Céline; Fetzer, Gregory J.

2016-07-01

This paper recalls the history of sodium guide star laser systems used in astronomy and space situational awareness adaptive optics, analyzing the impact that sodium laser technology evolution has had on routine telescope operations. While it would not be practical to describe every single sodium guide star laser system developed to date, it is possible to characterize their evolution in broad technology terms. The first generation of sodium lasers used dye laser technology to create the first sodium laser guide stars in Hawaii, California, and Spain in the late 1980s and 1990s. These experimental systems were turned into the first laser guide star facilities to equip mediumto- large diameter adaptive optics telescopes, opening a new era of Laser Guide Star Adaptive Optics (LGS AO)-enabled diffraction-limited imaging from the ground. Although they produced exciting scientific results, these laser guide star facilities were large, power-hungry and messy. In the USA, a second-generation of sodium lasers was developed in the 2000s that used cleaner, yet still large and complex, solid-state laser technology. These are the systems in routine operation at the 8 to 10m-class astronomical telescopes and 4m-class satellite imaging facilities today. Meanwhile in Europe, a third generation of sodium lasers was being developed using inherently compact and efficient fiber laser technology, and resulting in the only commercially available sodium guide star laser system to date. Fiber-based sodium lasers are being or will soon be deployed at three astronomical telescopes and two space surveillance stations. These highly promising systems are still relatively large to install on telescopes and they remain significantly expensive to procure and maintain. We are thus proposing to develop a fourth generation of sodium lasers: based on semiconductor technology, these lasers could provide a definitive solution to the problem of sodium LGS AO laser sources for all astronomy and space situational awareness applications.

Exhaust Plume Measurements of 15-Pound BATES (Ballistic Test and Evaluation System) Motors.

DTIC Science & Technology

1985-06-01

laser transmissometer measurements as a plume... System 7 3 AFRPL Laser Transmission/Scattering Measurement System During Motor Firing 8 4 Laser Scattering Detector Schematic 9 5 Laser Scattering... measurement goals. The instrumentation includes a multi -wavelength, single line-of-sight IR-E/A system , a UV emission spectrometer, an exhaust

Quantifying predictability variations in a low-order ocean-atmosphere model - A dynamical systems approach

NASA Technical Reports Server (NTRS)

Nese, Jon M.; Dutton, John A.

1993-01-01

The predictability of the weather and climatic states of a low-order moist general circulation model is quantified using a dynamic systems approach, and the effect of incorporating a simple oceanic circulation on predictability is evaluated. The predictability and the structure of the model attractors are compared using Liapunov exponents, local divergence rates, and the correlation and Liapunov dimensions. It was found that the activation of oceanic circulation increases the average error doubling time of the atmosphere and the coupled ocean-atmosphere system by 10 percent and decreases the variance of the largest local divergence rate by 20 percent. When an oceanic circulation develops, the average predictability of annually averaged states is improved by 25 percent and the variance of the largest local divergence rate decreases by 25 percent.

Patron Use of an Online Circulation System in Known-Item Searching.

ERIC Educational Resources Information Center

Specht, Jerry

1980-01-01

A study of patron use of the University of Illinois online circulation system (LCS) found that 56 percent of original known item searches and 86 percent of location searches were successful, and that graduate students use the system very differently from the way undergraduates use it. (FM)

Perspectives of using the 223-nm wavelength of the KrCl excimer laser for refractive surgery and for the treatment of some eye diseases

NASA Astrophysics Data System (ADS)

Bagayev, Sergei N.; Chernikh, Valery V.; Razhev, Alexander M.; Zhupikov, Andrey A.

2000-06-01

The new surgical UV ophthalmic laser system Medilex based on the KrCl (223 nm) excimer laser for refractive surgery was created. The comparative analysis of using the UV ophthalmic laser systems Medilex based on the ArF (193 nm) and the KrCl (223 nm) excimer lasers for the correction of refractive errors was performed. The system with the radiation wavelength of 223 nanometer of the KrCl excimer laser for refractive surgery was shown to have several medical and technical advantages over the system with the traditionally used radiation wavelength of 193 nanometer of the ArF excimer laser. In addition the use of the wavelength of 223 nanometer extends functional features of the system, allowing to make not only standard for this type systems surgical and therapeutic procedures but also to treat such ocular diseases as the glaucoma and herpetic keratities. For the UV ophthalmic laser systems Medilex three variations of the beam delivery system including special rotating masks and different beam homogenize systems were developed. All created beam delivery systems are able to make the correction of myopia, hyperopia, astigmatism and myopic or hyperopic astigmatism and may be used for therapeutic procedures. The results of the initial treatments of refractive error corrections using the UV ophthalmic laser systems Medilex for both photorefractive keratectomy (PRK) and LASIK procedures are presented.

Geometric calibration of a coordinate measuring machine using a laser tracking system

NASA Astrophysics Data System (ADS)

Umetsu, Kenta; Furutnani, Ryosyu; Osawa, Sonko; Takatsuji, Toshiyuki; Kurosawa, Tomizo

2005-12-01

This paper proposes a calibration method for a coordinate measuring machine (CMM) using a laser tracking system. The laser tracking system can measure three-dimensional coordinates based on the principle of trilateration with high accuracy and is easy to set up. The accuracy of length measurement of a single laser tracking interferometer (laser tracker) is about 0.3 µm over a length of 600 mm. In this study, we first measured 3D coordinates using the laser tracking system. Secondly, 21 geometric errors, namely, parametric errors of the CMM, were estimated by the comparison of the coordinates obtained by the laser tracking system and those obtained by the CMM. As a result, the estimated parametric errors agreed with those estimated by a ball plate measurement, which demonstrates the validity of the proposed calibration system.

State of the art of CO laser angioplasty system

NASA Astrophysics Data System (ADS)

Arai, Tsunenori; Mizuno, Kyoichi; Miyamoto, Akira; Sakurada, Masami; Kikuchi, Makoto; Kurita, Akira; Nakamura, Haruo; Takaoka, Hidetsugu; Utsumi, Atsushi; Takeuchi, Kiyoshi

1994-07-01

A unique percutaneous transluminal coronary angioplasty system new IR therapy laser with IR glass fiber delivery under novel angioscope guidance was described. Carbon monoxide (CO) laser emission of 5 mm in wavelength was employed as therapy laser to achieve precise ablation of atheromatous plaque with a flexible As-S IR glass fiber for laser delivery. We developed the first medical CO laser as well as As-S IR glass fiber cable. We also developed 5.5 Fr. thin angioscope catheter with complete directional manipulatability at its tip. The system control unit could manage to prevent failure irradiations and fiber damages. This novel angioplasty system was evaluated by a stenosis model of mongrel dogs. We demonstrated the usefulness of our system to overcome current issues on laser angioplasty using multifiber catheter with over-the-guidewire system.

Laser-induced damage threshold of camera sensors and micro-optoelectromechanical systems

NASA Astrophysics Data System (ADS)

Schwarz, Bastian; Ritt, Gunnar; Koerber, Michael; Eberle, Bernd

2017-03-01

The continuous development of laser systems toward more compact and efficient devices constitutes an increasing threat to electro-optical imaging sensors, such as complementary metal-oxide-semiconductors (CMOS) and charge-coupled devices. These types of electronic sensors are used in day-to-day life but also in military or civil security applications. In camera systems dedicated to specific tasks, micro-optoelectromechanical systems, such as a digital micromirror device (DMD), are part of the optical setup. In such systems, the DMD can be located at an intermediate focal plane of the optics and it is also susceptible to laser damage. The goal of our work is to enhance the knowledge of damaging effects on such devices exposed to laser light. The experimental setup for the investigation of laser-induced damage is described in detail. As laser sources, both pulsed lasers and continuous-wave (CW)-lasers are used. The laser-induced damage threshold is determined by the single-shot method by increasing the pulse energy from pulse to pulse or in the case of CW-lasers, by increasing the laser power. Furthermore, we investigate the morphology of laser-induced damage patterns and the dependence of the number of destructive device elements on the laser pulse energy or laser power. In addition to the destruction of single pixels, we observe aftereffects, such as persistent dead columns or rows of pixels in the sensor image.

Long lifetime near-infrared-emitting quantum dots for time-gated in vivo imaging of rare circulating cells (Conference Presentation)

NASA Astrophysics Data System (ADS)

Fragola, Alexandra; Bouccara, Sophie; Pezet, Sophie; Lequeux, Nicolas; Loriette, Vincent; Pons, Thomas

2017-02-01

The in vivo detection of rare circulating cells using non invasive fluorescence imaging would provide a key tool to study migration of eg. tumoral or immunological cells. Fluorescence detection is however currently limited by a lack of contrast between the small emission of isolated, fast circulating cells and the strong autofluorescence background of the surrounding tissues. We present the development of near infrared emitting quantum dots (NIR-QDs) with long fluorescence lifetime for sensitive time-gated in vivo imaging of circulating cells. These QDs are composed of low toxicity ZnCuInSe/ZnS materials and made biocompatible using a novel multidentate imidazole zwitterionic block copolymer, ensuring their long term intracellular stability. Cells of interest can thus be labeled ex vivo with QDs, injected intravenously and imaged in the near infrared range. Excitation using a pulsed laser coupled to time-gated detection enables the efficient rejection of short lifetime (≈ ns) autofluorescence background and detection of long lifetime (≈ 150 ns) fluorescence from QD-labeled cells. We demonstrate efficient in vivo imaging of single fast-flowing cells, which opens opportunities for future biological studies. [1] M. Tasso et al, "Sulfobetaine-Vinylimidazole block copolymers: a robust quantum dot surface chemistry expanding bioimaging's horizons", ACS Nano, 9(11), 2015 [2] S. Bouccara et al, "Time-gated cell imaging using long lifetime near-infrared-emitting quantum dots for autofluorescence rejection", J Biomed Optc, 19(5), 2014

Experimental study on natural circulation precooling of cryogenic pump system with gas phase inlet reflux configuration

NASA Astrophysics Data System (ADS)

Chen, G. B.; Zhong, Y. K.; Zheng, X. L.; Li, Q. F.; Xie, X. M.; Gan, Z. H.; Huang, Y. H.; Tang, K.; Kong, B.; Qiu, L. M.

2003-12-01

A novel gas-phase inlet configuration in the natural circulation system instead of the liquid-phase inlet is introduced to cool down a cryogenic pump system from room temperature to cryogenic temperatures, effectively. The experimental apparatus is illustrated and test process is described. Heat transfer and pressure drop data during the cool-down process are recorded and portrayed. By contrast with liquid-phase inlet configuration, experimental results demonstrate that the natural circulation with the gas-phase inlet configuration is an easier and more controllable way to cool down the pump system and maintain it at cryogenic temperatures.

Laser cutting system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dougherty, Thomas J

A workpiece cutting apparatus includes a laser source, a first suction system, and a first finger configured to guide a workpiece as it moves past the laser source. The first finger includes a first end provided adjacent a point where a laser from the laser source cuts the workpiece, and the first end of the first finger includes an aperture in fluid communication with the first suction system.

Ultra-fast laser system

DOEpatents

Dantus, Marcos; Lozovoy, Vadim V

2014-01-21

A laser system is provided which selectively excites Raman active vibrations in molecules. In another aspect of the present invention, the system includes a laser, pulse shaper and detection device. A further aspect of the present invention employs a femtosecond laser and binary pulse shaping (BPS). Still another aspect of the present invention uses a laser beam pulse, a pulse shaper and remote sensing.

Two Wavelength Ti:sapphire Laser for Ozone DIAL Measurements from Aircraft

NASA Technical Reports Server (NTRS)

Situ, Wen; DeYoung, Russel J.

1998-01-01

Laser remote sensing of ozone from aircraft has proven to be a valuable technique for understanding the distribution and dynamics of ozone in the atmosphere. Presently the differential absorption lidar (DIAL) technique, using dual ND:YAG lasers that are doubled to pump dye lasers which in turn are doubled into the UV for the "on" and "off' line lasers, is used on either the NASA DC-8 or P-3 aircraft. Typically, the laser output for each line is 40-mJ and this is split into two beams, one looking up and the other downward, each beam having about 20-mJ. The residual ND:YAG (1.06 micron) and dye laser energies are also transmitted to obtain information on the atmospheric aerosols. While this system has operated well, there are several system characteristics that make the system less than ideal for aircraft operations. The system, which uses separate "on" and "off" line lasers, is quite large and massive requiring valuable aircraft volume and weight. The dye slowly degrades with time requiring replacement. The laser complexity requires a number of technical people to maintain the system performance. There is also the future interest in deploying an ozone DIAL system in an Unpiloted Atmospheric Vehicle (UAV) which would require a total payload mass of less than 150 kg and power requirement of less than 1500 W. A laser technology has emerged that could potentially provide significant enhancements over the present ozone DIAL system. The flashlamp pumped Ti:sapphire laser system is an emerging technology that could reduce the mass and volume over the present system and also provide a system with fewer conversion steps, reducing system complexity. This paper will discuss preliminary results from a flashlamp-pumped Ti:sapphire laser constructed as a radiation source for a UV DIAL system to measure ozone.

Variable emissivity laser thermal control system

DOEpatents

Milner, J.R.

1994-10-25

A laser thermal control system for a metal vapor laser maintains the wall temperature of the laser at a desired level by changing the effective emissivity of the water cooling jacket. This capability increases the overall efficiency of the laser. 8 figs.

Surface modification of tooth root canal after application of an X-ray opaque waveguide

NASA Astrophysics Data System (ADS)

Dostálová, T.; Jelínková, H.; Šulc, J.; Němec, M.; Koranda, P.; Bartoňová, M.; Radina, P.; Miyagi, M.; Shi, Y.-W.; Matsuura, Y.

The interest in endodontic use of dental laser systems has been increasing. With the development of thin and flexible delivery systems for various wavelengths, laser applications in endodontics may become even more desirable. The aim of this study is to check the X-ray opacity of a hollow waveguide and to observe the results after laser root canal treatment. The root canal systems of 10 molars were treated endodontically by laser. For the laser radiation source, an Er:YAG laser system generating a wavelength of 2940 nm and an Alexandrite laser system generating a wavelength of 375 nm were used. The hollow waveguide used was checked under X-ray . A root canal surface treated by laser radiation was analyzed by a scanning electron microscope (SEM). The special hollow glass waveguide used was visible in the root canal system under X-ray imaging. Surface modification of the root canal after laser treatment was not found. After conventional treatment the root canal was enlarged. The surface was covered with a smear layer. After application of both laser systems, the smear layer was removed. The resulting canal surface was found to be clean and smooth. Under SEM observation open dentinal tubules were visible. No cracks were present, nor were surface modifications observed.

Method and system for powering and cooling semiconductor lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Telford, Steven J; Ladran, Anthony S

A semiconductor laser system includes a diode laser tile. The diode laser tile includes a mounting fixture having a first side and a second side opposing the first side and an array of semiconductor laser pumps coupled to the first side of the mounting fixture. The semiconductor laser system also includes an electrical pulse generator thermally coupled to the diode bar and a cooling member thermally coupled to the diode bar and the electrical pulse generator.

Electric motor for laser-mechanical drilling

DOEpatents

Grubb, Daryl L.; Faircloth, Brian O.; Zediker, Mark S.

2015-07-07

A high power laser drilling system utilizing an electric motor laser bottom hole assembly. A high power laser beam travels within the electric motor for advancing a borehole. High power laser drilling system includes a down hole electrical motor having a hollow rotor for conveying a high power laser beam through the electrical motor.

Laser source for dimensional metrology: investigation of an iodine stabilized system based on narrow linewidth 633 nm DBR diode

NASA Astrophysics Data System (ADS)

Rerucha, Simon; Yacoot, Andrew; Pham, Tuan M.; Cizek, Martin; Hucl, Vaclav; Lazar, Josef; Cip, Ondrej

2017-04-01

We demonstrated that an iodine stabilized distributed Bragg reflector (DBR) diode based laser system lasing at a wavelength in close proximity to λ =633 nm could be used as an alternative laser source to the helium-neon lasers in both scientific and industrial metrology. This yields additional advantages besides the optical frequency stability and coherence: inherent traceability, wider optical frequency tuning range, higher output power and high frequency modulation capability. We experimentally investigated the characteristics of the laser source in two major steps: first using a wavelength meter referenced to a frequency comb controlled with a hydrogen maser and then on an interferometric optical bench testbed where we compared the performance of the laser system with that of a traditional frequency stabilized He-Ne laser. The results indicate that DBR diode laser system provides a good laser source for applications in dimensional (nano)metrology, especially in conjunction with novel interferometric detection methods exploiting high frequency modulation or multiaxis measurement systems.

Tunable solid state lasers for remote sensing; Proceedings of the Conference, Stanford University, CA, October 1-3, 1984

NASA Technical Reports Server (NTRS)

Byer, R. L. (Editor); Trebino, R. (Editor); Gustafson, E. K. (Editor)

1985-01-01

Papers are presented on solid-state lasers for remote sensing, diode-pumped Nd:YAG lasers, and tunable solid-state-laser systems. Topics discussed include titanium-sapphire tunable laser systems, the performance of slab geometry, and the development of slab lasers. Consideration is given to garnet host solid-state lasers, the growth of lasers and nonlinear materials, and nonlinear frequency conversion and tunable sources.

Event-driven management algorithm of an Engineering documents circulation system

NASA Astrophysics Data System (ADS)

Kuzenkov, V.; Zebzeev, A.; Gromakov, E.

2015-04-01

Development methodology of an engineering documents circulation system in the design company is reviewed. Discrete event-driven automatic models using description algorithms of project management is offered. Petri net use for dynamic design of projects is offered.

Staff Training Aspects of Circulation System Implementation.

ERIC Educational Resources Information Center

Juergens, Bonnie

1979-01-01

Presents program guidelines for training library staff in the operation and use of automated library circulation systems. Advice is given on the qualificatons of the training coordinator, levels of training, training and training aids, vendor responsibilities and time frame. (RAA)

Free-space QKD system hacking by wavelength control using an external laser.

PubMed

Lee, Min Soo; Woo, Min Ki; Jung, Jisung; Kim, Yong-Su; Han, Sang-Wook; Moon, Sung

2017-05-15

We develop a way to hack free-space quantum key distribution (QKD) systems by changing the wavelength of the quantum signal laser using an external laser. Most free-space QKD systems use four distinct lasers for each polarization, thereby making the characteristics of each laser indistinguishable. We also discover a side-channel that can distinguish the lasers by using an external laser. Our hacking scheme identifies the lasers by automatically applying the external laser to each signal laser at different intensities and detecting the wavelength variation according to the amount of incident external laser power. We conduct a proof-of-principle experiment to verify the proposed hacking structure and confirm that the wavelength varies by several gigahertzes to several nanometers, depending on the intensity of the external laser. The risk of hacking is successfully proven through the experimental results. Methods for prevention are also suggested.

Immune Defenses of the Invasive Apple Snail Pomacea canaliculata (Caenogastropoda, Ampullariidae): Phagocytic Hemocytes in the Circulation and the Kidney

PubMed Central

Vega, Israel A.; Castro-Vazquez, Alfredo

2015-01-01

Hemocytes in the circulation and kidney islets, as well as their phagocytic responses to microorganisms and fluorescent beads, have been studied in Pomacea canaliculata, using flow cytometry, light microscopy (including confocal laser scanning microscopy) and transmission electron microscopy (TEM). Three circulating hemocyte types (hyalinocytes, agranulocytes and granulocytes) were distinguished by phase contrast microscopy of living cells and after light and electron microscopy of fixed material. Also, three different populations of circulating hemocytes were separated by flow cytometry, which corresponded to the three hemocyte types. Hyalinocytes showed a low nucleus/cytoplasm ratio, and no apparent granules in stained material, but showed granules of moderate electron density under TEM (L granules) and at least some L granules appear acidic when labeled with LysoTracker Red. Both phagocytic and non-phagocytic hyalinocytes lose most (if not all) L granules when exposed to microorganisms in vitro. The phagosomes formed differed whether hyalinocytes were exposed to yeasts or to Gram positive or Gram negative bacteria. Agranulocytes showed a large nucleus/cytoplasm ratio and few or no granules. Granulocytes showed a low nucleus/cytoplasm ratio and numerous eosinophilic granules after staining. These granules are electron dense and rod-shaped under TEM (R granules). Granulocytes may show merging of R granules into gigantic ones, particularly when exposed to microorganisms. Fluorescent bead exposure of sorted hemocytes showed phagocytic activity in hyalinocytes, agranulocytes and granulocytes, but the phagocytic index was significantly higher in hyalinocytes. Extensive hemocyte aggregates ('islets') occupy most renal hemocoelic spaces and hyalinocyte-like cells are the most frequent component in them. Presumptive glycogen deposits were observed in most hyalinocytes in renal islets (they also occur in the circulation but less frequently) and may mean that hyalinocytes participate in the storage and circulation of this compound. Injection of microorganisms in the foot results in phagocytosis by hemocytes in the islets, and the different phagosomes formed are similar to those in circulating hyalinocytes. Dispersed hemocytes were obtained after kidney collagenase digestion and cell sorting, and they were able to phagocytize fluorescent beads. A role for the kidney as an immune barrier is proposed for this snail. PMID:25893243

Immune Defenses of the Invasive Apple Snail Pomacea canaliculata (Caenogastropoda, Ampullariidae): Phagocytic Hemocytes in the Circulation and the Kidney.

PubMed

Cueto, Juan A; Rodriguez, Cristian; Vega, Israel A; Castro-Vazquez, Alfredo

2015-01-01

Hemocytes in the circulation and kidney islets, as well as their phagocytic responses to microorganisms and fluorescent beads, have been studied in Pomacea canaliculata, using flow cytometry, light microscopy (including confocal laser scanning microscopy) and transmission electron microscopy (TEM). Three circulating hemocyte types (hyalinocytes, agranulocytes and granulocytes) were distinguished by phase contrast microscopy of living cells and after light and electron microscopy of fixed material. Also, three different populations of circulating hemocytes were separated by flow cytometry, which corresponded to the three hemocyte types. Hyalinocytes showed a low nucleus/cytoplasm ratio, and no apparent granules in stained material, but showed granules of moderate electron density under TEM (L granules) and at least some L granules appear acidic when labeled with LysoTracker Red. Both phagocytic and non-phagocytic hyalinocytes lose most (if not all) L granules when exposed to microorganisms in vitro. The phagosomes formed differed whether hyalinocytes were exposed to yeasts or to Gram positive or Gram negative bacteria. Agranulocytes showed a large nucleus/cytoplasm ratio and few or no granules. Granulocytes showed a low nucleus/cytoplasm ratio and numerous eosinophilic granules after staining. These granules are electron dense and rod-shaped under TEM (R granules). Granulocytes may show merging of R granules into gigantic ones, particularly when exposed to microorganisms. Fluorescent bead exposure of sorted hemocytes showed phagocytic activity in hyalinocytes, agranulocytes and granulocytes, but the phagocytic index was significantly higher in hyalinocytes. Extensive hemocyte aggregates ('islets') occupy most renal hemocoelic spaces and hyalinocyte-like cells are the most frequent component in them. Presumptive glycogen deposits were observed in most hyalinocytes in renal islets (they also occur in the circulation but less frequently) and may mean that hyalinocytes participate in the storage and circulation of this compound. Injection of microorganisms in the foot results in phagocytosis by hemocytes in the islets, and the different phagosomes formed are similar to those in circulating hyalinocytes. Dispersed hemocytes were obtained after kidney collagenase digestion and cell sorting, and they were able to phagocytize fluorescent beads. A role for the kidney as an immune barrier is proposed for this snail.

Development of the micro-scanning optical system of yellow laser applied to the ophthalmologic area

NASA Astrophysics Data System (ADS)

Ortega, Tiago A.; Mota, Alessandro D.; Costal, Glauco Z.; Fontes, Yuri C.; Rossi, Giuliano; Yasuoka, Fatima M. M.; Stefani, Mario A.; de Castro N., Jarbas C.

2012-10-01

In this work, the development of a laser scanning system for ophthalmology with micrometric positioning precision is presented. It is a semi-automatic scanning system for retina photocoagulation and laser trabeculoplasty. The equipment is a solid state laser fully integrated to the slit lamp. An optical system is responsible for producing different laser spot sizes on the image plane and a pair of galvanometer mirrors generates the scanning patterns.

High power laser workover and completion tools and systems

DOEpatents

Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O; Koblick, Yeshaya; Moxley, Joel F

2014-10-28

Workover and completion systems, devices and methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena. Systems and devices for the laser workover and completion of a borehole in the earth. These systems and devices can deliver high power laser energy down a deep borehole, while maintaining the high power to perform laser workover and completion operations in such boreholes deep within the earth.

Optical radiation hazards of laser welding processes. Part II: CO2 laser.

PubMed

Rockwell, R J; Moss, C E

1989-08-01

There has been an extensive growth within the last five years in the use of high-powered lasers in various metalworking processes. The two types of lasers used most frequently for laser welding/cutting processes are the Neodymium-yttrium-aluminum-garnet (Nd:YAG) and the carbon dioxide (CO2) systems. When such lasers are operated in an open beam configuration, they are designated as a Class IV laser system. Class IV lasers are high-powered lasers that may present an eye and skin hazard under most common exposure conditions, either directly or when the beam has been diffusely scattered. Significant control measures are required for unenclosed (open beam), Class IV laser systems since workers may be exposed to scattered or reflected beams during the operation, maintenance, and service of these lasers. In addition to ocular and/or skin exposure hazards, such lasers also may present a multitude of nonlaser beam occupational concerns. Radiant energy measurements are reported for both the scattered laser radiation and the plasma-related plume radiations released during typical high-powered CO2 laser-target interactions. In addition, the application of the nominal hazard zone (NHZ) and other control measures also are discussed with special emphasis on Class IV industrial CO2 laser systems.

Lasers à électrons libres de courtes longueurs d'onde: état de l'art et perspectives

NASA Astrophysics Data System (ADS)

Couprie, M. E.

2003-06-01

Les Lasers à Électrons Libres (LEL) sont des sources de rayonnement cohérent et accordable, basées sur l'interaction d'un faisceau d'électrons relativistes circulant dans le champ magnétique magnétique périodique et permanent créé par un “onduleur”. et d'une onde optique. L'onde lumineuse peut être issue de l'émission de rayonnement synchroton émise par le paquet d'électrons a chaque passage pour un système super-radiant en mode SASE (Self Amplified Spontaneous Emission- Emission Spontanée Auto-Amplifiée) ou issue du rayonnement synchrotron stocké dans une cavité optique, en mode oscillateur, ou d'une onde laser externe, en mode génération d'harmonique. Sous certaines conditions, l'onde lumineuse est amplifiée, au détriment de l'énergie cinétique des électrons, ce qui conduit à l'effet laser. L'état de l'art des sources Laser à Electrons Libres dans l'UV et le VUV est présenté, en indiquant les complémentarités résultant des différentes configurations tant du point de vue des sources que de leurs utilisations. Les projets de sources de courte longueur d'onde proposés sont ensuite discutés.

Nd:YAG laser system for ophthalmic microsurgery

NASA Astrophysics Data System (ADS)

Savastru, Dan; Ristici, Esofina; Dragu, T.; Cotirlan, C.; Miclos, Sorin; Mustata, Marina

2005-04-01

The Nd:YAG solid state laser can be used in ophthalmologic microsurgery because of its specific wavelength of 1064 nm, which has the property to penetrate the transparent medium of the eye. We design a specific ophthalmic system, containing a Q-switch Nd:YAG laser, an optical stereomicroscope and an aiming system. This laser-stereomicroscope system is used for eye examination and for microsurgical proceedings like posterior capsulotomy and pupilar membranectomy. We had to design an optical scheme of the laser to settle the radiation route. In order to cover the medical domain of the energies, we calibrate eleven attenuation filters using ratiometric method. For a correct position of the place where the laser pulse strikes, we used an original system consisting of two red laser diodes mounted on each side of the binocular One of the advantages of this laser system is taht the output energies can be varied widely (0.8-15 mJ), making a great numbers of applications in clinical ophthalmology possible.

Development of Fiber-Based Laser Systems for LISA

NASA Technical Reports Server (NTRS)

Numata, Kenji; Camp, Jordan

2010-01-01

We present efforts on fiber-based laser systems for the LISA mission at the NASA Goddard Space Flight Center. A fiber-based system has the advantage of higher robustness against external disturbances and easier implementation of redundancies. For a master oscillator, we are developing a ring fiber laser and evaluating two commercial products, a DBR linear fiber laser and a planar-waveguide external cavity diode laser. They all have comparable performance to a traditional NPRO at LISA band. We are also performing reliability tests of a 2-W Yb fiber amplifier and radiation tests of fiber laser/amplifier components. We describe our progress to date and discuss the path to a working LISA laser system design.

Biomedical effects of low-power laser controlled by electroacupuncture

NASA Astrophysics Data System (ADS)

Kalenchits, Nadezhda I.; Nicolaenko, Andrej A.; Shpilevoj, Boris N.

1997-12-01

The methods and technical facilities of testing the biomedical effects caused by the influence of low-power laser radiation in the process of laser therapy are presented. Described studies have been conducted by means of the complex of fireware facilities consisting of the system of electroacupuncture diagnostics (EA) and a system of laser therapy on the basis of multichannel laser and magneto-laser devices. The task of laser therapy was concluded in undertaking acupuncture anaesthetization, achievement of antioedemic and dispersional actions, raising tone of musculus and nervous system, normalization of immunity factors under the control of system EA. The 82 percent to 95 percent agreement of the result of an electroacupuncture diagnostics with clinical diagnoses were achieved.

Laser System for Photoelectron and X-Ray Production in the PLEIADES Compton Light Source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gibson, D J; Barty, C J; Betts, S M

2005-04-21

The PLEIADES (Picosecond Laser-Electron Interaction for the Dynamic Evaluation of Structures) facility provides tunable short x-ray pulses with energies of 30-140 keV and pulse durations of 0.3-5 ps by scattering an intense, ultrashort laser pulse off a 35-75 MeV electron beam. Synchronization of the laser and electron beam is obtained by using a photoinjector gun, and using the same laser system to generate the electrons and the scattering laser. The Ti Ti:Sapphire, chirped pulse amplification based 500 mJ, 50 fs, 810 nm scattering laser and the similar 300 {micro}J, 5 ps, 266 nm photoinjector laser systems are detailed. Additionally, anmore » optical parametric chirped pulse amplification (OPCPA) system is studied as a replacement for part of the scattering laser front end. Such a change would significantly simplify the set-up the laser system by removing the need for active switching optics, as well as increase the pre-pulse contrast ratio which will be important when part of the scattering laser is used as a pump beam in pump-probe diffraction experiments using the ultrashort tunable x-rays generated as the probe.« less

Atomic vapor laser isotope separation process

DOEpatents

Wyeth, R.W.; Paisner, J.A.; Story, T.

1990-08-21

A laser spectroscopy system is utilized in an atomic vapor laser isotope separation process. The system determines spectral components of an atomic vapor utilizing a laser heterodyne technique. 23 figs.

Robotic Laser Coating Removal System

DTIC Science & Technology

2008-07-01

Materiel Command IRR Internal Rate of Return JTP Joint Test Protocol JTR Joint Test Report LARPS Large Area Robotic Paint Stripping LASER Light...use of laser paint stripping systems is applicable to depainting activities on large off-aircraft components and weapons systems for the Air Force...The use of laser paint stripping systems is applicable to depainting activities on large off-aircraft components and weapons systems for the Air

New Laser System For Combined Monitoring And Treatment Of Neonatal Hyperbilirubinemia

NASA Astrophysics Data System (ADS)

Hamza, Mostafa; Hamza, Mohammad

1989-09-01

Laser photoradiation therapy for neonatal hyperbilirubinemia is a breakthrough in the management of neonatal jaundice. In this paper the authors present a new laser system that provides combined monitoring and therapy for neonatal hyperbilirubinemia. The new system incorporates tunable laser sources that can be operated at selected wavelengths to achieve both transcutaneous differential absorption measurements of bilirubin concentration in addition to laser photoradiation therapy. The new laser system can allow the treating physician to avoid over or under treatment of jaundiced neonates by the control of serum bilirubin from a critically high level to a reasonably safe level.

Spatio-temporal characterisation of a 100 kHz 24 W sub-3-cycle NOPCPA laser system

NASA Astrophysics Data System (ADS)

Witting, Tobias; Furch, Federico J.; Vrakking, Marc J. J.

2018-04-01

In recent years, OPCPA and NOPCPA laser systems have shown the potential to supersede Ti:sapphire plus post-compression based laser systems to drive next generation attosecond light sources via direct amplification of few-cycle pulses to high pulse energies at high repetition rates. In this paper, we present a sub 3-cycle, 100 kHz, 24 W NOPA laser system and characterise its spatio-temporal properties using the SEA-F-SPIDER technique. Our results underline the importance of spatio-temporal diagnostics for these emerging laser systems.

A quantitative analysis of microcirculation in sore-prone pressure areas on conventional and pressure relief hospital mattresses using laser Doppler flowmetry and tissue spectrophotometry.

PubMed

Rothenberger, Jens; Krauss, Sabrina; Held, Manuel; Bender, Dominik; Schaller, Hans-Eberhard; Rahmanian-Schwarz, Afshin; Constantinescu, Mihai Adrian; Jaminet, Patrick

2014-11-01

Pressure ulcers are associated with severe impairment for the patients and high economic load. With this study we wanted to gain more insight to the skin perfusion dynamics due to external loading. Furthermore, we evaluated the effect of different types of pressure relief mattresses. A total of 25 healthy volunteers were enrolled in the study. Perfusion dynamics of the sacral and the heel area were assessed using the O2C-device, which combines a laser light, to determine blood flow, and white light to determine the relative amount of hemoglobin. Three mattresses were evaluated compared to a hard surface: a standard hospital foam mattress bed, a visco-elastic foam mattress, and an air-fluidized bed. In the heel area, only the air-fluidized bed was able to maintain the blood circulation (mean blood flow of 13.6 ± 6 versus 3.9 ± 3 AU and mean relative amount of hemoglobin of 44.0 ± 14 versus 32.7 ± 12 AU.) In the sacral area, all used mattresses revealed an improvement of blood circulation compared to the hard surface. The results of this study form a more precise pattern of perfusion changes due to external loading on various pressure relief mattresses. This knowledge may reduce the incidence of pressure ulcers and may be an influencing factor in pressure relief mattress selection. Copyright © 2014 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

Material Processing with High Power CO2-Lasers

NASA Astrophysics Data System (ADS)

Bakowsky, Lothar

1986-10-01

After a period of research and development lasertechnique now is regarded as an important instrument for flexible, economic and fully automatic manufacturing. Especially cutting of flat metal sheets with high power C02-lasers and CNC controlled two or three axes handling systems is a wide spread. application. Three dimensional laser cutting, laser-welding and -heat treatment are just at the be ginning of industrial use in production lines. The main. advantages of laser technology. are - high. accuracy - high, processing velocity - law thermal distortion. - no tool abrasion. The market for laser material processing systems had 1985 a volume of 300 Mio S with growth rates between, 20 % and 30 %. The topic of this lecture are hiTrh. power CO2-lasers. Besides this systems two others are used as machining tools, Nd-YAG- and Eximer lasers. All applications of high. power CO2-lasers to industrial material processing show that high processing velocity and quality are only guaranteed in case of a stable intensity. profile on the workpiece. This is only achieved by laser systems without any power and mode fluctuations and by handling systems of high accuracy. Two applications in the automotive industry are described, below as examples for laser cutting and laser welding of special cylindrical motor parts.

Fiber coupled optical spark delivery system

DOEpatents

Yalin, Azer; Willson, Bryan; Defoort, Morgan

2008-08-12

A spark delivery system for generating a spark using a laser beam is provided, the spark delivery system including a laser light source and a laser delivery assembly. The laser delivery assembly includes a hollow fiber and a launch assembly comprising launch focusing optics to input the laser beam in the hollow fiber. In addition, the laser delivery assembly includes exit focusing optics that demagnify an exit beam of laser light from the hollow fiber, thereby increasing the intensity of the laser beam and creating a spark. In accordance with embodiments of the present invention, the assembly may be used to create a spark in a combustion engine. In accordance with other embodiments of the present invention, a method of using the spark delivery system is provided. In addition, a method of choosing an appropriate fiber for creating a spark using a laser beam is also presented.

Laser technologies in ophthalmic surgery

NASA Astrophysics Data System (ADS)

Atezhev, V. V.; Barchunov, B. V.; Vartapetov, S. K.; Zav'yalov, A. S.; Lapshin, K. E.; Movshev, V. G.; Shcherbakov, I. A.

2016-08-01

Excimer and femtosecond lasers are widely used in ophthalmology to correct refraction. Laser systems for vision correction are based on versatile technical solutions and include multiple hard- and software components. Laser characteristics, properties of laser beam delivery system, algorithms for cornea treatment, and methods of pre-surgical diagnostics determine the surgical outcome. Here we describe the scientific and technological basis for laser systems for refractive surgery developed at the Physics Instrumentation Center (PIC) at the Prokhorov General Physics Institute (GPI), Russian Academy of Sciences.

Laser Technology in Interplanetary Exploration: The Past and the Future

NASA Technical Reports Server (NTRS)

Smith, David E.

2000-01-01

Laser technology has been used in planetary exploration for many years but it has only been in the last decade that laser altimeters and ranging systems have been selected as flight instruments alongside cameras, spectrometers, magnetometers, etc. Today we have an active laser system operating at Mars and another destined for the asteroid Eros. A few years ago a laser ranging system on the Clementine mission changed much of our thinking about the moon and in a few years laser altimeters will be on their way to Mercury, and also to Europa. Along with the increased capabilities and reliability of laser systems has came the realization that precision ranging to the surface of planetary bodies from orbiting spacecraft enables more scientific problems to be addressed, including many associated with planetary rotation, librations, and tides. In addition, new Earth-based laser ranging systems working with similar systems on other planetary bodies in an asynchronous transponder mode will be able to make interplanetary ranging measurements at the few cm level and will advance our understanding of solar system dynamics and relativistic physics.

Coherent Laser Radar System Theory.

DTIC Science & Technology

1987-11-05

This program is aimed at developing a system theory for the emerging technology of multifunction coherent CO2 laser radars. It builds upon previous...work funded by U.S. Army Research Office contract DAAG29-80-K-0022. Keywords include: Laser radar theory, Radar system theory , and Laser speckle.

Detection and capture of breast cancer cells with photoacoustic flow cytometry

NASA Astrophysics Data System (ADS)

Bhattacharyya, Kiran; Goldschmidt, Benjamin S.; Viator, John A.

2016-08-01

According to the Centers for Disease Control and Prevention, breast cancer is the most common cancer and the second leading cause of cancer related deaths among women. Metastasis-the presence of secondary tumors caused by the spread of cancer cells via the circulatory or lymphatic systems-significantly worsens the prognosis of any breast cancer patient. A technique is developed to detect circulating breast cancer cells in human blood using a photoacoustic flow cytometry method. A Q-switched laser is used to interrogate thousands of blood cells with one pulse as they flow through the beam path. Cells that are optically absorbing, either naturally or artificially, emit an ultrasound wave as a result of the photoacoustic (PA) effect. Breast cancer cells are targeted with chromophores through immunochemistry in order to enhance optical absorption. After which, the PA cytometry device is calibrated to demonstrate the ability to detect single cells. Cultured breast cancer cells are added to whole blood to reach a biologically relevant concentration of about 25 to 45 breast cancer cells per 1 mL of blood. An in vitro PA flow cytometer is used to detect and isolate these cells followed by capture with the use of a micromanipulator. This method can not only be used to determine the disease state of the patient and the response to therapy but also it can be used for genetic testing and in vitro drug trials since the circulating cell can be captured and studied.

Comparative PIV and LDA studies of Newtonian and non-Newtonian flows in an agitated tank.

PubMed

Story, Anna; Jaworski, Zdzisław; Simmons, Mark J; Nowak, Emilia

2018-01-01

The paper presents results of an experimental study of the fluid velocity field in a stirred tank equipped with a Prochem Maxflo T (PMT) type impeller which was rotating at a constant frequency of N  = 4.1 or 8.2 s -1 inducing transitional ( Re  = 499 or 1307) or turbulent ( Re  = 2.43 × 10 4 ) flow of the fluid. The experiments were performed for a Newtonian fluid (water) and a non-Newtonian fluid (0.2 wt% aqueous solution of carboxymethyl cellulose, CMC) exhibiting mild viscoelastic properties. Measurements were carried out using laser light scattering on tracer particles which follow the flow (2-D PIV). For both the water and the CMC solution one primary and two secondary circulation loops were observed within the fluid volume; however, the secondary loops were characterized by much lower intensity. The applied PMT-type impeller produced in the Newtonian fluid an axial primary flow, whilst in the non-Newtonian fluid the flow was more radial. The results obtained in the form of the local mean velocity components were in satisfactory agreement with the literature data from LDA. Distribution of the shear rate in the studied system was also analyzed. For the non-Newtonian fluid an area was computed where the elastic force dominates over the viscous one. The area was nearly matching the region occupied by the primary circulation loop.

Methods for measuring right ventricular function and hemodynamic coupling with the pulmonary vasculature.

PubMed

Bellofiore, Alessandro; Chesler, Naomi C

2013-07-01

The right ventricle (RV) is a pulsatile pump, the efficiency of which depends on proper hemodynamic coupling with the compliant pulmonary circulation. The RV and pulmonary circulation exhibit structural and functional differences with the more extensively investigated left ventricle (LV) and systemic circulation. In light of these differences, metrics of LV function and efficiency of coupling to the systemic circulation cannot be used without modification to characterize RV function and efficiency of coupling to the pulmonary circulation. In this article, we review RV physiology and mechanics, established and novel methods for measuring RV function and hemodynamic coupling, and findings from application of these methods to RV function and coupling changes with pulmonary hypertension. We especially focus on non-invasive measurements, as these may represent the future for clinical monitoring of disease progression and the effect of drug therapies.

A STRATEGY FOR PROTECTING CIRCULATING SEAWATER SYSTEMS FROM OIL SPILLS

EPA Science Inventory

A strategy is described for establishing a simple, inexpensive monitoring program for determining approximate levels of petroleum hydrocarbons in ambient water collected near intake structures of circulating seawater systems. The ambient water is obtained from the depth of intake...

Study of lubricant circulation in HVAC systems. Volume 1: Description of technical effort and results; Final technical report, March 1995--April 1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biancardi, F.R.; Michels, H.H.; Sienel, T.H.

1996-10-01

The purpose of this program was to conduct experimental and analytical efforts to determine lubricant circulation characteristics of new HFC/POE pairs and HFC/mineral oil pairs in a representative central residential HVAC system and to compare their behavior with the traditional HCFC-22/mineral oil (refrigerant/lubricant) pair. A dynamic test facility was designed and built to conduct the experimental efforts. This facility provided a unique capability to visually and physically measure oil circulation rates, on-line, in operating systems. A unique on-line ultraviolet-based measurement device was used to obtain detailed data on the rate and level of lubricant oil circulated within the operating heatmore » pump system. The experimental and analytical data developed during the program are presented as a function of vapor velocity, refrigerant/lubricant viscosity, system features and equipment. Both visual observations and instrumentation were used to understand ``worst case`` oil circulation situations. This report is presented in two volumes. Volume 1 contains a complete description of the program scope, objective, test results summary, conclusions, description of test facility and recommendations for future effort. Volume 2 contains all of the program test data essentially as taken from the laboratory dynamic test facility during the sequence of runs.« less

Experimental investigation on laser-induced plasma ignition of hydrocarbon fuel in scramjet engine at takeover flight conditions

NASA Astrophysics Data System (ADS)

Li, Xipeng; Liu, Weidong; Pan, Yu; Yang, Leichao; An, Bin

2017-09-01

Laser-induced plasma ignition of an ethylene fuelled cavity is successfully conducted in a model scramjet engine combustor with dual cavities. The simulated flight condition corresponds to takeover flight Mach 4, with isolator entrance Mach number of 2.1, the total pressure of 0.65 MPa and stagnation temperature of 947 K. Ethylene is injected 35 mm upstream of cavity flameholder from four orifices with 2-mm-diameter. The 1064 nm laser beam, from a Q-switched Nd:YAG laser source running at 10 Hz and 940 mJ per pulse, is focused into cavity for ignition. High speed photography is used to capture the transient ignition process. The laser-induced gas breakdown, flame kernel generation and propagation are all recorded and ensuing stable supersonic combustion is established in cavity. The highly ionized plasma zone is almost round at starting, and then the surface of the flame kernel is wrinkled severely in 150 μs after the laser pulse due to the strong turbulence flow in cavity. The flame kernel is found rotating anti-clockwise and gradually moves upstream as the entrainment of circulation flow in cavity. The flame is stabilized at the corner of the cavity for about 200 μs, and then spreads from leading edge to trailing edge via the under part of shear layer to fully fill the entire cavity. The corner recirculation zone of cavity is of great importance for flame spreading. Eventually, a cavity shear-layer stabilized combustion is established in the supersonic flow roughly 2.9 ms after the laser pulse. Both the temporal evolution of normalized chemiluminescence intensity and normalized flame area show that the entire ignition process can be divided into four stages, which are referred as turbulent dissipation stage, combustion enhancement stage, reverting stage and combustion stabilization stage. The results show promising potentials of laser induced plasma for ignition in real scramjets.

[Laser biostimulation in the treatment of pleurisy].

PubMed

Milojević, Momir; Kuruc, Vesna

2003-01-01

Low-intensity lasers have been utilized in medicine in two ways: for local stimulation and for stimulation of acupuncture points. Literature data reveal that this method has been indiscriminately applied in psychiatry, rheumatology, gynecology, dermatology, otorhinolaryngology, in diverse acute and chronic pains, inflammations, vascular disorders, angina pectoris, bronchial asthma. Most commonly reported clinical effects are analgesia, spasmolytic and anti-inflammatory effects, as well as faster wound and bone healing. This prospective study analyses effects of laser biostimulation on patients with pleurisy. The analysis included 25 patients treated at the Institute of Lung Diseases in Sremska Kamenica during 2000, 2001 and 2002. Apart from conservative treatment, these patients were treated with laser biostimulation of acupuncture points and local region for ten days. During treatment, changes of present clinical signs, general symptoms, radiological findings, as well as changes of some relevant biochemical parameters were recorded. Results were compared with the control group which included the same number of patients, who differed from the examined group only by not being exposed to laser biostimulation. The examined group of patients with pleuritis presented with quicker resorption of pleural effusion, less pleural adhesions, more significant decrease of clinical symptoms, especially pain, as well as more significant increase of cortisol and immunoglobulin A and decrease of circulating immune complexes (CIC), leukocytes and sedimentation rate than the control group. Mechanisms of laser biostimulation in treatment of pleurisy were described in detail and the obtained results were correlated to those reported by other authors. 1. Patients with pleurisy undergoing laser stimulation presented with faster resorption of effusion and remission of the subjective symptoms, as well as significant decrease of biochemical acute inflammation parameters in the peripheral blood and therefore with faster recovery. 2. In patients with pleurisy laser treatment increases regenerative mechanisms of the pleural surface, thus decreasing the quantity of formed adhesions and resulting in better mobility of the diaphragm.

[Classification of laser irradiation and safety measures].

PubMed

Takac, S; Stojanović, S

1998-01-01

The use of lasers in medicine and especially surgery is rapidly expanding in many disciplines from clinical laboratory to the office practice and operating room. It is essential that users of this powerful tool have knowledge of their potential hazards and the measures to protect patients and personnel against injuries or undesired effects. Below, we have included information about the way lasers are classified; the development of protective standards; the current status of protection standards that apply to lasers, especially those used in medicine/surgery; the specific kinds of hazards associated with medical/surgical applications; and the measures by which hazards have been controlled. Since laser technology is still a young field, it is likely that problems unknown at present will occur and methodologies for controlling hazards will evolve. The American National Standards Committee produced the first consensus standard Z136.1 in 1973. The Standard was revised in 1976 to accommodate differences in biological effects for different wavelengths in the visible spectrum. The ANSI Standard has been revised again in 1980, and currently (1984) there are two additional standards in preparation, Z136.2 and 136.3, which treat the safe use of light-emitting diodes and the safe use of lasers in the health care environment, respectively. Most surgical and medical lasers are Class III or IV. Some lasers have a Class IV therapy level beam plus a Class I or II alignment beam. When using lasers, it is possible to generate incandescence or fluorescence in an irradiated object. This can occur even with protective eyewear, because the correlated radiations are usually of a different wavelength. Generally, this should not be a problem when beams are directed at biological material. However, hazard could be caused by lasers designed to produce fluorescence. Control of correlative radiation in a laser system is required in the federal regulations. Hazards of lasers may be grouped as those to the eye, skin and associated hazards, fire, x-rays, electrical, fumes, toxic materials, etc. Effects on tissue are governed by the following factors:--the energy or power density of the beam;--the absorption in tissue at the laser wavelength;--the time the beam is held at a given area.;--the protective effects of heat removal by thermal conduction and by circulation. Eye hazards include thermal burns or acoustical disruption (shock waves) from high-powered or high-energy beams in the visible and near infrared wavelengths. Direct beam exposure or specular or diffuse reflaction from these very high-power lasers can also cause injuries to other parts of the retina. For example, beams can directly penetrate through the sclera and cause retinal injury. Near ultraviolet (less than 400 hm) and far infrared (.3000 hm including CO2 lasers) can cause moderate to severe corneal burns. Far ultraviolet (200-315 nm), mid infrared (1400-3000 nanometers) can cause welders' flash or snow blindness and chronic exposure could cause cataract, and exposure to ultraviolet rays may be carcinogenic. For CO2 lasers, the far infrared radiation is attenuated by plastic goggles, or by glasses, or quartz. Other eyewear with special filters is used for different lasers. The whole personnel who may be exposed to direct beams, specular reflections, and many times diffuse reflections must wear protective eyewear. In all cases the surgeon and others viewing the procedure through the endoscope need glasses or suitable protective lenses installed in the endoscope. Persons who are not viewing the beam may not need to wear protective glasses with the same level of optical density. Glasses may be selected to provide protection for lasers operating in the visible wavelength to the point where the normal aversion response could protect the individual.

Automated Circulation Systems in Libraries Serving the Blind and Physically Handicapped: A Reference Guide for Planning.

ERIC Educational Resources Information Center

Wanger, Judith; And Others

Designed to facilitate communications in future automation projects between library and data processing personnel, especially those projects involving the use of automated systems in the service of disabled patrons, this guide identifies and describes a master set of major circulation system requirements and design considerations, and illustrates…

Library Specifications for a New Circulation System for Concordia University Libraries.

ERIC Educational Resources Information Center

Tallon, James

This study of library requirements for a new circulation system is organized into three sections: (1) items required for initial implementation in July 1982; (2) items relating to notice generation and activity statistics, with implementation expected by fall 1982; and (3) items provided in the system as initially implemented, with additional…

Manipulating parallel circuits: the perioperative management of patients with complex congenital cardiac disease.

PubMed

Lawrenson, John; Eyskens, Benedicte; Vlasselaers, Dirk; Gewillig, Marc

2003-08-01

In all patients undergoing cardiac surgery, the effective delivery of oxygen to the tissues is of paramount importance. In the patient with relatively normal cardiac structures, the pulmonary and systemic circulations are relatively independent of each other. In the patient with a functional single ventricle, the pulmonary and systemic circulations are dependent on the same pump. As a consequence of this interdependency, the haemodynamic changes following complex palliative procedures, such as the Norwood operation, can be difficult to understand. Comparison of the newly created surgical connections to a simple set of direct current electrical circuits may help the practitioner to successfully care for the patient. In patients undergoing complex palliations, the pulmonary and systemic circulations can be compared to two circuits in parallel. Manipulations of variables, such as resistance or flow, in one circuit, can profoundly affect the performance of the other circuit. A large pulmonary flow might result in a large increase in the saturation of haemoglobin with oxygen returning to the heart via the pulmonary veins at the expense of a decreased systemic flow. Accurate balancing of these parallel circulations requires an appreciation of all interventions that can affect individual components of both circulations.

Laser-induced damage threshold of camera sensors and micro-opto-electro-mechanical systems

NASA Astrophysics Data System (ADS)

Schwarz, Bastian; Ritt, Gunnar; Körber, Michael; Eberle, Bernd

2016-10-01

The continuous development of laser systems towards more compact and efficient devices constitutes an increasing threat to electro-optical imaging sensors such as complementary metal-oxide-semiconductors (CMOS) and charge-coupled devices (CCD). These types of electronic sensors are used in day-to-day life but also in military or civil security applications. In camera systems dedicated to specific tasks, also micro-opto-electro-mechanical systems (MOEMS) like a digital micromirror device (DMD) are part of the optical setup. In such systems, the DMD can be located at an intermediate focal plane of the optics and it is also susceptible to laser damage. The goal of our work is to enhance the knowledge of damaging effects on such devices exposed to laser light. The experimental setup for the investigation of laser-induced damage is described in detail. As laser sources both pulsed lasers and continuous-wave (CW) lasers are used. The laser-induced damage threshold (LIDT) is determined by the single-shot method by increasing the pulse energy from pulse to pulse or in the case of CW-lasers, by increasing the laser power. Furthermore, we investigate the morphology of laser-induced damage patterns and the dependence of the number of destructed device elements on the laser pulse energy or laser power. In addition to the destruction of single pixels, we observe aftereffects like persisting dead columns or rows of pixels in the sensor image.

Laser material processing system

DOEpatents

Dantus, Marcos

2015-04-28

A laser material processing system and method are provided. A further aspect of the present invention employs a laser for micromachining. In another aspect of the present invention, the system uses a hollow waveguide. In another aspect of the present invention, a laser beam pulse is given broad bandwidth for workpiece modification.

[Effect of Alloxan-induced diabetes mellitus on the functions of bone marrow-derived and circulating endothelial progenitor cells].

PubMed

Tan, Q; Li, G P; Wang, Q S; Zheng, C H; Zhang, S Y

2017-07-25

Objective: To explore whether diabetes mellitus (DM) impairs functions of bone marrow-derived endothelial progenitor cells (BM-EPC) and circulating EPC. Methods: Diabetic model of rabbit was induced by Alloxan injection and the rabbits were then randomly divided into three groups: BM-EPC group, circulating EPC group, and DM group, with six rabbits in each group. Another 6 normal rabbits were enrolled as normal control group as well. 8 weeks later, BM-EPC and circulating EPC from diabetic and healthy rabbits were isolated and cultured. Colony number, proliferation, adhesion and tube formation function were detected. Exogenous diabetic BM-EPC and circulating EPC were analyzed for therapeutic efficacy in acute ischemia model of diabetic rabbits. Left ventricular (LV) function was assessed using Echocardiography. Capillary density and fibrosis area were evaluated by confocal laser scanning microscope (CLSM) and Masson-trichrome staining. The mRNA expression of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) was analyzed using real-time quantitive PCR. Results: Colony number, proliferation, adhesion and tube formation function of diabetic circulating EPC were significantly reduced compared with healthy rabbits. DM impaired tube-forming ability of BM-EPC, but did not influence colony number, proliferation and adhesion function. Compared with circulating EPC and control group, BM-EPC group had fewer fibrosis area (6.98%±0.94% vs 13.03%±2.97% and 15.84%±4.74%, both P =0.001), higher capillary density [(792±87) vs (528±71) and (372±77) vessels/mm(2,) both P <0.001], higher mRNA expression of VEGF (6.25±2.33 vs 2.19±1.01 and 1.55±0.52, both P <0.001) and bFGF (6.38±2.65 vs 1.24±0.76 and 1.18±0.82, both P <0.001), higher left ventricular ejection fraction (LVEF) (61%±4% vs 47%±5% and 50%±10%, both P <0.05). Conclusions: DM not only impaired functions of circulating EPC, but also influenced tube formation function of BM-EPC. Auto transplantation of BM-EPC may rescue the ischemic myocardium by neovascularization and paracrine effect in diabetic rabbits.

Intravital multiphoton fluorescence imaging and optical manipulation of spinal cord in mice, using a compact fiber laser system.

PubMed

Oshima, Yusuke; Horiuch, Hideki; Honkura, Naoki; Hikita, Atsuhiko; Ogata, Tadanori; Miura, Hiromasa; Imamura, Takeshi

2014-09-01

Near-infrared ultrafast lasers are widely used for multiphoton excited fluorescence microscopy in living animals. Ti:Sapphire lasers are typically used for multiphoton excitation, but their emission wavelength is restricted below 1,000 nm. The aim of this study is to evaluate the performance of a compact Ytterbium-(Yb-) fiber laser at 1,045 nm for multiphoton excited fluorescence microscopy in spinal cord injury. In this study, we employed a custom-designed microscopy system with a compact Yb-fiber laser and evaluated the performance of this system in in vivo imaging of brain cortex and spinal cord in YFP-H transgenic mice. For in vivo imaging of brain cortex, sharp images of basal dendrites, and pyramidal cells expressing EYFP were successfully captured using the Yb-fiber laser in our microscopy system. We also performed in vivo imaging of axon fibers of spinal cord in the transgenic mice. The obtained images were almost as sharp as those obtained using a conventional ultrafast laser system. In addition, laser ablation and multi-color imaging could be performed simultaneously using the Yb-fiber laser. The high-peak pulse Yb-fiber laser is potentially useful for multimodal bioimaging methods based on a multiphoton excited fluorescence microscopy system that incorporates laser ablation techniques. Our results suggest that microscopy systems of this type could be utilized in studies of neuroscience and clinical use in diagnostics and therapeutic tool for spinal cord injury in the future. © 2014 Wiley Periodicals, Inc.

Modematic: a fast laser beam analyzing system for high power CO2-laser beams

NASA Astrophysics Data System (ADS)

Olsen, Flemming O.; Ulrich, Dan

2003-03-01

The performance of an industrial laser is very much depending upon the characteristics of the laser beam. The ISO standards 11146 and 11154 describing test methods for laser beam parameters have been approved. To implement these methods in industry is difficult and especially for the infrared laser sources, such as the CO2-laser, the availabl analyzing systems are slow, difficult to apply and having limited reliability due to the nature of the detection methods. In an EUREKA-project the goal was defined to develop a laser beam analyzing system dedicated to high power CO2-lasers, which could fulfill the demands for an entire analyzing system, automating the time consuming pre-alignment and beam conditioning work required before a beam mode analyses, automating the analyzing sequences and data analysis required to determine the laser beam caustics and last but not least to deliver reliable close to real time data to the operator. The results of this project work will be described in this paper. The research project has led to the development of the Modematic laser beam analyzer, which is ready for the market.

Noise Reduction Through Circulation Control

NASA Technical Reports Server (NTRS)

Munro, Scott E.; Ahuja, K. K.; Englar, Robert J.

2005-01-01

Circulation control technology uses tangential blowing around a rounded trailing edge or a leading edge to change the force and moment characteristics of an aerodynamic body. This technology has been applied to circular cylinders, wings, helicopter rotors, and even to automobiles for improved aerodynamic performance. Only limited research has been conducted on the acoustic of this technology. Since wing flaps contribute to the environmental noise of an aircraft, an alternate blown high lift system without complex mechanical flaps could prove beneficial in reducing the noise of an approaching aircraft. Thus, in this study, a direct comparison of the acoustic characteristics of high lift systems employing a circulation control wing configuration and a conventional wing flapped configuration has been made. These results indicate that acoustically, a circulation control wing high lift system could be considerably more acceptable than a wing with conventional mechanical flaps.

High precision, rapid laser hole drilling

DOEpatents

Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

2007-03-20

A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

High precision, rapid laser hole drilling

DOEpatents

Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

2005-03-08

A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

High precision, rapid laser hole drilling

DOEpatents

Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

2013-04-02

A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

Output power stability of a HCN laser using a stepping motor for the EAST interferometer system

NASA Astrophysics Data System (ADS)

Zhang, J. B.; Wei, X. C.; Liu, H. Q.; Shen, J. J.; Zeng, L.; Jie, Y. X.

2015-11-01

The HCN laser on EAST is a continuous wave glow discharge laser with 3.4 m cavity length and 120 mW power output at 337 μ m wavelength. Without a temperature-controlled system, the cavity length of the laser is very sensitive to the environmental temperature. An external power feedback control system is applied on the HCN laser to stabilize the laser output power. The feedback system is composed of a stepping motor, a PLC, a supervisory computer, and the corresponding control program. One step distance of the stepping motor is 1 μ m and the time response is 0.5 s. Based on the power feedback control system, a stable discharge for the HCN laser is obtained more than eight hours, which satisfies the EAST experiment.

Fiber Lasers and Amplifiers for Space-based Science and Exploration

NASA Technical Reports Server (NTRS)

Yu, Anthony W.; Krainak, Michael A.; Stephen, Mark A.; Chen, Jeffrey R.; Coyle, Barry; Numata, Kenji; Camp, Jordan; Abshire, James B.; Allan, Graham R.; Li, Steven X.;

Light's Darkness

ScienceCinema

Padgett, Miles [University of Glasgow, Glasgow, Scotland

2017-12-09

Optical vortices and orbital angular momentum are currently topical subjects in the optics literature. Although seemingly esoteric, they are, in fact, the generic state of light and arise whenever three or more plane waves interfere. To be observed by eye the light must be monochromatic. Laser speckle is one such example, where the optical energy circulates around each black spot, giving a local orbital angular momentum. This talk with report three on-going studies. First, when considering a volume of interfering waves, the laser specs map out threads of complete darkness embedded in the light. Do these threads form loops? Links? Or even knots? Second, when looking through a rapidly spinning window, the image of the world on the other side is rotated: true or false? Finally, the entanglement of orbital angular momentum states means measuring how the angular position of one photons sets the angular momentum of another: is this an angular version of the EPR (Einstein, Podolsky, and Rosen) paradox?

970-nm ridge waveguide diode laser bars for high power DWBC systems

NASA Astrophysics Data System (ADS)

Wilkens, Martin; Erbert, Götz; Wenzel, Hans; Knigge, Andrea; Crump, Paul; Maaßdorf, Andre; Fricke, Jörg; Ressel, Peter; Strohmaier, Stephan; Schmidt, Berthold; Tränkle, Günther

2018-02-01

de lasers are key components in material processing laser systems. While mostly used as pump sources for solid state or fiber lasers, direct diode laser systems using dense wavelength multiplexing have come on the market in recent years. These systems are realized with broad area lasers typically, resulting in beam quality inferior to disk or fiber lasers. We will present recent results of highly efficient ridge waveguide (RW) lasers, developed for dense-wavelength-beamcombining (DWBC) laser systems expecting beam qualities comparable to solid state laser systems and higher power conversion efficiencies (PCE). The newly developed RW lasers are based on vertical structures with an extreme double asymmetric large optical cavity. Besides a low vertical divergence these structures are suitable for RW-lasers with (10 μm) broad ridges, emitting in a single mode with a good beam quality. The large stripe width enables a lateral divergence below 10° (95 % power content) and a high PCE by a comparably low series resistance. We present results of single emitters and small test arrays under different external feedback conditions. Single emitters can be tuned from 950 nm to 975 nm and reach 1 W optical power with more than 55 % PCE and a beam quality of M2 < 2 over the full wavelength range. The spectral width is below 30 pm FWHM. 5 emitter arrays were stabilized using the same setup. Up to now we reached 3 W optical power, limited by power supply, with 5 narrow spectral lines.

Lasers in orthodontics

PubMed Central

Nalcaci, Ruhi; Cokakoglu, Serpil

2013-01-01

Many types of dental lasers are currently available that can be efficiently used for soft and hard tissue applications in the field of orthodontics. For achieving the desired effects in the target tissue, knowledge of laser characteristics such as power, wavelength and timing, is necessary. Laser therapy is advantageous because it often avoids bleeding, can be pain free, is non-invasive and is relatively quick. The high cost is its primary disadvantage. It is very important to take the necessary precautions to prevent possible tissue damage when using laser dental systems. Here, we reviewed the main types and characteristics of laser systems used in dental practice and discuss the applications of lasers in orthodontics, harmful effects and laser system safety. PMID:24966719

Laser Doppler velocimetry for continuous flow solar-pumped iodine laser system

NASA Technical Reports Server (NTRS)

Tabibi, Bagher M.; Lee, Ja H.

1991-01-01

A laser Doppler velocimetry (LDV) system was employed to measure the flow velocity profile of iodide vapor inside laser tubes of 36 mm ID and 20 mm ID. The LDV, which was operated in the forward scatter mode used a low power (15 mW) He-Ne laser beam. Velocity ranges from 1 m/s was measured to within one percent accuracy. The flow velocity profile across the laser tube was measured and the intensity of turbulence was determined. The flow of iodide inside the laser tube demonstrated a mixture of both turbulence and laminar flow. The flowmeter used for the laser system previously was calibrated with the LDV and found to be in good agreement.

Laser beam delivery at ELI-NP

DOE PAGES

Ursescu, Daniel; Cheriaux, G.; Audebert, P.; ...

2017-01-01

The Laser Beam Delivery (LBD) system technical design report covers the interface between the High Power Laser System (HPLS) and the experiments, together with the pulse quality management. Here, the laser transport part of the LBD has a number of subsystems as follows: the beam transport lines for the six main outputs of HPLS, the additional short and long pulses and the synchronization system including the timing of the laser pulses with the Gamma Beam System (GBS) and the experiments on femtosecond timescale. Pulse quality management, discussed further here, consist in the generation and delivery of multiple HPLS pulses, coherentmore » combining of the HPLS arms, laser pulse diagnostics on target, laser beam dumps, shutters and output energy adaption.« less

In situ conversion process utilizing a closed loop heating system

DOEpatents

Sandberg, Chester Ledlie [Palo Alto, CA; Fowler, Thomas David [Houston, TX; Vinegar, Harold J [Bellaire, TX; Schoeber, Willen Jan Antoon Henri

2009-08-18

An in situ conversion system for producing hydrocarbons from a subsurface formation is described. The system includes a plurality of u-shaped wellbores in the formation. Piping is positioned in at least two of the u-shaped wellbores. A fluid circulation system is coupled to the piping. The fluid circulation system is configured to circulate hot heat transfer fluid through at least a portion of the piping to form at least one heated portion of the formation. An electrical power supply is configured to provide electrical current to at least a portion of the piping located below an overburden in the formation to resistively heat at least a portion of the piping. Heat transfers from the piping to the formation.

Development of laser transmission system

NASA Astrophysics Data System (ADS)

Song, Jiawu; Zhang, Yulan; Yang, Jiandong; Zhang, Xinming

1998-08-01

This paper discusses a light transfer system of therapeutic machine using carbon-dioxide laser. This system is based on imitating human being arm motion principle, consists of optical cardans mainly and can move in three-D space freely. Through it carbon-dioxide laser (which wavelength is 10.6 micrometer) is reflected, focused or diverged and transferred to the different therapeutic part of body to realize the purpose of cutting operation, gasification, cauterization and irradiation. This system includes an indicating system using He-Ne laser, by which carbon-dioxide laser can arrive therapeutic part accurately. This system possesses some advantages e.g. an accurate transfer, large moving range, small power consumption, high power density and easy operation. At present the occupancy in home market of this kind laser transfer system products is over 95%. Some products have been exported to other countries.

Airborne Laser Systems Testing and Analysis (essals et analyse des systemes laser embarques)

DTIC Science & Technology

2010-04-01

of Surface/ Paints Reflection Properties (PILASTER targets); • PILASTER Sensors Testing and Calibration; • LOAS Laser System Testing; and • Test...PILASTER targets candidate paints and materials), a Laser Scatter-meter (LSM) was built. To briefly summarise the fundamental concepts involved...Green Painted Target. 7.6.3 Laser Beam Misalignment with Respect to the Beam-Expander Support For measuring the beam misalignment, the beam expander

Personal medical information system using laser card

NASA Astrophysics Data System (ADS)

Cho, Seong H.; Kim, Keun Ho; Choi, Hyung-Sik; Park, Hyun Wook

1996-04-01

The well-known hospital information system (HIS) and the picture archiving and communication system (PACS) are typical applications of multimedia to medical area. This paper proposes a personal medical information save-and-carry system using a laser card. This laser card is very useful, especially in emergency situations, because the medical information in the laser card can be read at anytime and anywhere if there exists a laser card reader/writer. The contents of the laser card include the clinical histories of a patient such as clinical chart, exam result, diagnostic reports, images, and so on. The purpose of this system is not a primary diagnosis, but emergency reference of clinical history of the patient. This personal medical information system consists of a personal computer integrated with laser card reader/writer, color frame grabber, color CCD camera and a high resolution image scanner optionally. Window-based graphical user interface was designed for easy use. The laser card has relatively sufficient capacity to store the personal medical information, and has fast access speed to restore and load the data with a portable size as compact as a credit card. Database items of laser card provide the doctors with medical data such as laser card information, patient information, clinical information, and diagnostic result information.

Efficient quantum circuits for dense circulant and circulant like operators

PubMed Central

Zhou, S. S.

2017-01-01

Circulant matrices are an important family of operators, which have a wide range of applications in science and engineering-related fields. They are, in general, non-sparse and non-unitary. In this paper, we present efficient quantum circuits to implement circulant operators using fewer resources and with lower complexity than existing methods. Moreover, our quantum circuits can be readily extended to the implementation of Toeplitz, Hankel and block circulant matrices. Efficient quantum algorithms to implement the inverses and products of circulant operators are also provided, and an example application in solving the equation of motion for cyclic systems is discussed. PMID:28572988

Development of an Accident Reproduction Simulator System Using a Hemodialysis Extracorporeal Circulation System.

PubMed

Nishite, Yoshiaki; Takesawa, Shingo

2016-01-01

Accidents that occur during dialysis treatment are notified to the medical staff via alarms raised by the dialysis apparatus. Similar to such real accidents, apparatus activation or accidents can be reproduced by simulating a treatment situation. An alarm that corresponds to such accidents can be utilized in the simulation model. The aim of this study was to create an extracorporeal circulation system (hereinafter, the circulation system) for dialysis machines so that it sets off five types of alarms for: 1) decreased arterial pressure, 2) increased arterial pressure, 3) decreased venous pressure, 4) increased venous pressure, and 5) blood leakage, according to the five types of accidents chosen based on their frequency of occurrence and the degree of severity. In order to verify the alarm from the dialysis apparatus connected to the circulation system and the accident corresponding to it, an evaluation of the alarm for its reproducibility of an accident was performed under normal treatment circumstances. The method involved testing whether the dialysis apparatus raised the desired alarm from the moment of control of the circulation system, and measuring the time it took until the desired alarm was activated. This was tested on five main models from four dialyzer manufacturers that are currently used in Japan. The results of the tests demonstrated successful activation of the alarms by the dialysis apparatus, which were appropriate for each of the five types of accidents. The time between the control of the circulatory system to the alarm signal was as follows, 1) venous pressure lower limit alarm: 7 seconds; 2) venous pressure lower limit: 8 seconds; 3) venous pressure upper limit: 7 seconds; 4) venous pressure lower limit alarm: 2 seconds; and 5) blood leakage alarm: 19 seconds. All alarms were set off in under 20 seconds. Thus, we can conclude that a simulator system using an extracorporeal circulation system can be set to different models of dialyzers, and that the reproduced treatment scenarios can be used for simulation training.

A Multi-Component Automated Laser-Origami System for Cyber-Manufacturing

NASA Astrophysics Data System (ADS)

Ko, Woo-Hyun; Srinivasa, Arun; Kumar, P. R.

2017-12-01

Cyber-manufacturing systems can be enhanced by an integrated network architecture that is easily configurable, reliable, and scalable. We consider a cyber-physical system for use in an origami-type laser-based custom manufacturing machine employing folding and cutting of sheet material to manufacture 3D objects. We have developed such a system for use in a laser-based autonomous custom manufacturing machine equipped with real-time sensing and control. The basic elements in the architecture are built around the laser processing machine. They include a sensing system to estimate the state of the workpiece, a control system determining control inputs for a laser system based on the estimated data and user’s job requests, a robotic arm manipulating the workpiece in the work space, and middleware, named Etherware, supporting the communication among the systems. We demonstrate automated 3D laser cutting and bending to fabricate a 3D product as an experimental result.

Method and system for communicating with a laser power driver

DOEpatents

Telford, Steven

2017-07-18

A system for controlling a plurality of laser diodes includes an optical transmitter coupled to the laser diode driver for each laser diode. An optical signal including bi-phase encoded data is provided to each laser diode driver. The optical signal includes current level and pulse duration information at which each of the diodes is to be driven. Upon receiving a trigger signal, the laser diode drivers operate the laser diodes using the current level and pulse duration information to output a laser beam.

X-ray laser system, x-ray laser and method

DOEpatents

London, Richard A.; Rosen, Mordecai D.; Strauss, Moshe

1992-01-01

Disclosed is an x-ray laser system comprising a laser containing generating means for emitting short wave length radiation, and means external to said laser for energizing said generating means, wherein when the laser is in an operative mode emitting radiation, the radiation has a transverse coherence length to width ratio of from about 0.05 to 1. Also disclosed is a method of adjusting the parameters of the laser to achieve the desired coherence length to laser width ratio.

V-shaped resonators for addition of broad-area laser diode arrays

DOEpatents

Liu, Bo; Liu, Yun; Braiman, Yehuda Y.

2012-12-25

A system and method for addition of broad-area semiconductor laser diode arrays are described. The system can include an array of laser diodes, a V-shaped external cavity, and grating systems to provide feedback for phase-locking of the laser diode array. A V-shaped mirror used to couple the laser diode emissions along two optical paths can be a V-shaped prism mirror, a V-shaped stepped mirror or include multiple V-shaped micro-mirrors. The V-shaped external cavity can be a ring cavity. The system can include an external injection laser to further improve coherence and phase-locking.

Laser Sources for Generation of Ultrasound

NASA Technical Reports Server (NTRS)

Wagner, James W.

1996-01-01

Two laser systems have been built and used to demonstrate enhancements beyond current technology used for laser-based generation and detection of ultrasound. The first system consisted of ten Nd:YAG laser cavities coupled electronically and optically to permit sequential bursts of up to ten laser pulses directed either at a single point or configured into a phased array of sources. Significant enhancements in overall signal-to-noise ratio for laser ultrasound incorporating this new source system was demonstrated, using it first as a source of narrowband ultrasound and secondly as a phased array source producing large enhanced signal displacements. A second laser system was implemented using ultra fast optical pulses from a Ti:Sapphire laser to study a new method for making laser generated ultrasonic measurements of thin films with thicknesses on the order of hundreds of angstroms. Work by prior investigators showed that such measurements could be made based upon fluctuations in the reflectivity of thin films when they are stressed by an arriving elastic pulse. Research performed using equipment purchased under this program showed that a pulsed interferometric system could be used as well as a piezoreflective detection system to measure pulse arrivals even in thin films with very low piezoreflective coefficients.

Non-contact finger vein acquisition system using NIR laser

NASA Astrophysics Data System (ADS)

Kim, Jiman; Kong, Hyoun-Joong; Park, Sangyun; Noh, SeungWoo; Lee, Seung-Rae; Kim, Taejeong; Kim, Hee Chan

2009-02-01

Authentication using finger vein pattern has substantial advantage than other biometrics. Because human vein patterns are hidden inside the skin and tissue, it is hard to forge vein structure. But conventional system using NIR LED array has two drawbacks. First, direct contact with LED array raise sanitary problem. Second, because of discreteness of LEDs, non-uniform illumination exists. We propose non-contact finger vein acquisition system using NIR laser and Laser line generator lens. Laser line generator lens makes evenly distributed line laser from focused laser light. Line laser is aimed on the finger longitudinally. NIR camera was used for image acquisition. 200 index finger vein images from 20 candidates are collected. Same finger vein pattern extraction algorithm was used to evaluate two sets of images. Acquired images from proposed non-contact system do not show any non-uniform illumination in contrary with conventional system. Also results of matching are comparable to conventional system. We developed Non-contact finger vein acquisition system. It can prevent potential cross contamination of skin diseases. Also the system can produce uniformly illuminated images unlike conventional system. With the benefit of non-contact, proposed system shows almost equivalent performance compared with conventional system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Grubb, Daryl L.; Faircloth, Brian O.; Zediker, Mark S.

A high power laser drilling system utilizing an electric motor laser bottom hole assembly. A high power laser beam travels within the electric motor for performing a laser operation. A system includes a down hole electrical motor having a hollow rotor for conveying a high power laser beam having a wavelength less than 1060 nm through the electrical motor.

High Energy 2-Micron Laser Developments

NASA Technical Reports Server (NTRS)

Yu, Jirong; Trieu, Bo C.; Petros, Mulugeta; Bai, Yingxin; Petzar, Paul J.; Koch, Grady J.; Singh, Upendra N.; Kavaya, Michael J.

2007-01-01

A master oscillator power amplifier, high energy Q-switched 2-micron laser system has been recently demonstrated. The laser and amplifiers are all designed in side-pumped rod configuration, pumped by back-cooled conductive packaged GaAlAs diode laser arrays. This 2-micron laser system provides nearly transform limited beam quality.

Co-Production of Electricity and Hydrogen Using a Novel Iron-based Catalyst

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hilaly, Ahmad; Georgas, Adam; Leboreiro, Jose

2011-09-30

The primary objective of this project was to develop a hydrogen production technology for gasification applications based on a circulating fluid-bed reactor and an attrition resistant iron catalyst. The work towards achieving this objective consisted of three key activities: Development of an iron-based catalyst suitable for a circulating fluid-bed reactor; Design, construction, and operation of a bench-scale circulating fluid-bed reactor system for hydrogen production; Techno-economic analysis of the steam-iron and the pressure swing adsorption hydrogen production processes. This report describes the work completed in each of these activities during this project. The catalyst development and testing program prepared and iron-basedmore » catalysts using different support and promoters to identify catalysts that had sufficient activity for cyclic reduction with syngas and steam oxidation and attrition resistance to enable use in a circulating fluid-bed reactor system. The best performing catalyst from this catalyst development program was produced by a commercial catalyst toll manufacturer to support the bench-scale testing activities. The reactor testing systems used during material development evaluated catalysts in a single fluid-bed reactor by cycling between reduction with syngas and oxidation with steam. The prototype SIP reactor system (PSRS) consisted of two circulating fluid-bed reactors with the iron catalyst being transferred between the two reactors. This design enabled demonstration of the technical feasibility of the combination of the circulating fluid-bed reactor system and the iron-based catalyst for commercial hydrogen production. The specific activities associated with this bench-scale circulating fluid-bed reactor systems that were completed in this project included design, construction, commissioning, and operation. The experimental portion of this project focused on technical demonstration of the performance of an iron-based catalyst and a circulating fluid-bed reactor system for hydrogen production. Although a technology can be technically feasible, successful commercial deployment also requires that a technology offer an economic advantage over existing commercial technologies. To effective estimate the economics of this steam-iron process, a techno-economic analysis of this steam iron process and a commercial pressure swing adsorption process were completed. The results from this analysis described in this report show the economic potential of the steam iron process for integration with a gasification plant for coproduction of hydrogen and electricity.« less

Design of a cost-effective laser spot tracker

NASA Astrophysics Data System (ADS)

Artan, Göktuǧ Gencehan; Sari, Hüseyin

2017-05-01

One of the most important aspects of guided systems is detection. The most convenient detection in the sense of precision can be achieved with a laser spot tracker. This study deals with a military grade, high performance and cost-effective laser spot tracker for a guided system. The aim is to develop a high field of view system that will detect a laser spot from a distance of 3 kilometers in which the target is designated from 3 kilometers with a laser. The study basically consists of the system design, modeling, producing and the conducting performance tests of the whole system.

11-kW direct diode laser system with homogenized 55 × 20 mm2 Top-Hat intensity distribution

NASA Astrophysics Data System (ADS)

Köhler, Bernd; Noeske, Axel; Kindervater, Tobias; Wessollek, Armin; Brand, Thomas; Biesenbach, Jens

2007-02-01

In comparison with other laser systems diode lasers are characterized by a unique overall efficiency, a small footprint and high reliability. However, one major drawback of direct diode laser systems is the inhomogeneous intensity distribution in the far field. Furthermore the output power of current commercially available systems is limited to about 6 kW. We report on a diode laser system with 11 kW output power at a single wavelength of 940 nm aiming for customer specific large area treatment. To the best of our knowledge this is the highest output power reported so far for a direct diode laser system. In addition to the high output power the intensity distribution of the laser beam is homogenized in both axes leading to a 55 x 20 mm2 Top-Hat intensity profile at a working distance of 400 mm. Homogeneity of the intensity distribution is better than 90%. The intensity in the focal plane is 1 kW/cm2. We will present a detailed characterization of the laser system, including measurements of power, power stability and intensity distribution of the homogenized laser beam. In addition we will compare the experimental data with the results of non-sequential raytracing simulations.

High-power beam combining: a step to a future laser weapon system

NASA Astrophysics Data System (ADS)

Protz, Rudolf; Zoz, Jürgen; Geidek, Franz; Dietrich, Stephan; Fall, Michael

2012-11-01

Due to the enormous progress in the field of high-power fiber lasers during the last years commercial industrial fiber lasers are now available, which deliver a near-diffraction limited beam with power levels up to10kW. For the realization of a future laser weapon system, which can be used for Counter-RAM or similar air defence applications, a laser source with a beam power at the level of 100kW or more is required. At MBDA Germany the concept for a high-energy laser weapon system is investigated, which is based on such existing industrial laser sources as mentioned before. A number of individual high-power fiber laser beams are combined together, using one common beam director telescope. By this "geometric" beam coupling scheme, sufficient laser beam power for an operational laser weapon system can be achieved. The individual beams from the different lasers are steered by servo-loops, using fast tip-tilt mirrors. This principle enables the concentration of the total laser beam power at the common focal point on a distant target, also allowing fine tracking of target movements and first order compensation of turbulence effects on laser beam propagation. The proposed beam combination concept was demonstrated using several experimental set-ups. Different experiments were performed, to investigate laser beam target interaction and target fine tracking also at large distances. Content and results of these investigations are reported. An example for the lay-out of an Air Defence High Energy Laser Weapon (ADHELW ) is given. It can be concluded, that geometric high-power beam combining is an important step for the realization of a laser weapon system in the near future.

Development and optimization of a diode laser for photodynamic therapy.

PubMed

Lim, Hyun Soo

2011-01-01

This study demonstrated the development of a laser system for cancer treatment with photodynamic therapy (PDT) based on a 635 nm laser diode. In order to optimize efficacy in PDT, the ideal laser system should deliver a homogeneous nondivergent light energy with a variable spot size and specific wavelength at a stable output power. We developed a digital laser beam controller using the constant current method to protect the laser diode resonator from the current spikes and other fluctuations, and electrical faults. To improve the PDT effects, the laser system should deliver stable laser energy in continuous wave (CW), burst mode and super burst mode, with variable irradiation times depending on the tumor type and condition. The experimental results showed the diode laser system described herein was eminently suitable for PDT. The laser beam was homogeneous without diverging and the output power increased stably and in a linear manner from 10 mW to 1500 mW according to the increasing input current. Variation between the set and delivered output was less than 7%. The diode laser system developed by the author for use in PDT was compact, user-friendly, and delivered a stable and easily adjustable output power at a specific wavelength and user-set emission modes.

Development and optimization of a diode laser for photodynamic therapy

PubMed Central

Lim, Hyun Soo

2011-01-01

Background and Aims: This study demonstrated the development of a laser system for cancer treatment with photodynamic therapy (PDT) based on a 635 nm laser diode. In order to optimize efficacy in PDT, the ideal laser system should deliver a homogeneous nondivergent light energy with a variable spot size and specific wavelength at a stable output power. Materials and Methods: We developed a digital laser beam controller using the constant current method to protect the laser diode resonator from the current spikes and other fluctuations, and electrical faults. To improve the PDT effects, the laser system should deliver stable laser energy in continuous wave (CW), burst mode and super burst mode, with variable irradiation times depending on the tumor type and condition. Results and Comments: The experimental results showed the diode laser system described herein was eminently suitable for PDT. The laser beam was homogeneous without diverging and the output power increased stably and in a linear manner from 10 mW to 1500 mW according to the increasing input current. Variation between the set and delivered output was less than 7%. Conclusions: The diode laser system developed by the author for use in PDT was compact, user-friendly, and delivered a stable and easily adjustable output power at a specific wavelength and user-set emission modes. PMID:24155529

An auto-locked diode laser system for precision metrology

NASA Astrophysics Data System (ADS)

Beica, H. C.; Carew, A.; Vorozcovs, A.; Dowling, P.; Pouliot, A.; Barron, B.; Kumarakrishnan, A.

2017-05-01

We present a unique external cavity diode laser system that can be auto-locked with reference to atomic and molecular spectra. The vacuum-sealed laser head design uses an interchangeable base-plate comprised of a laser diode and optical elements that can be selected for desired wavelength ranges. The feedback light to the laser diode is provided by a narrow-band interference filter, which can be tuned from outside the laser cavity to fineadjust the output wavelength in vacuum. To stabilize the laser frequency, the digital laser controller relies either on a pattern-matching algorithm stored in memory, or on first or third derivative feedback. We have used the laser systems to perform spectroscopic studies in rubidium at 780 nm, and in iodine at 633 nm. The linewidth of the 780-nm laser system was measured to be ˜500 kHz, and we present Allan deviation measurements of the beat note and the lock stability. Furthermore, we show that the laser system can be the basis for a new class of lidar transmitters in which a temperature-stabilized fiber-Bragg grating is used to generate frequency references for on-line points of the transmitter. We show that the fiber-Bragg grating spectra can be calibrated with reference to atomic transitions.

Digital frequency offset-locked He–Ne laser system with high beat frequency stability, narrow optical linewidth and optical fibre output

NASA Astrophysics Data System (ADS)

Sternkopf, Christian; Manske, Eberhard

2018-06-01

We report on the enhancement of a previously-presented heterodyne laser source on the basis of two phase-locked loop (PLL) frequency coupled internal-mirror He–Ne lasers. Our new system consists of two digitally controlled He–Ne lasers with slightly different wavelengths, and offers high-frequency stability and very narrow optical linewidth. The digitally controlled system has been realized by using a FPGA controller and transconductance amplifiers. The light of both lasers was coupled into separate fibres for heterodyne interferometer applications. To enhance the laser performance we observed the sensitivity of both laser tubes to electromagnetic noise from various laser power supplies and frequency control systems. Furthermore, we describe how the linewidth of a frequency-controlled He–Ne laser can be reduced during precise frequency stabilisation. The digitally controlled laser source reaches a standard beat frequency deviation of less than 20 Hz (with 1 s gate time) and a spectral full width at half maximum (FWHM) of the beat signal less than 3 kHz. The laser source has enough optical output power to serve a fibre-coupled multi axis heterodyne interferometer. The system can be adjusted to output beat frequencies in the range of 0.1 MHz–20 MHz.

Design of Complex Systems to Achieve Passive Safety: Natural Circulation Cooling of Liquid Salt Pebble Bed Reactors

NASA Astrophysics Data System (ADS)

Scarlat, Raluca Olga

This dissertation treats system design, modeling of transient system response, and characterization of individual phenomena and demonstrates a framework for integration of these three activities early in the design process of a complex engineered system. A system analysis framework for prioritization of experiments, modeling, and development of detailed design is proposed. Two fundamental topics in thermal-hydraulics are discussed, which illustrate the integration of modeling and experimentation with nuclear reactor design and safety analysis: thermal-hydraulic modeling of heat generating pebble bed cores, and scaled experiments for natural circulation heat removal with Boussinesq liquids. The case studies used in this dissertation are derived from the design and safety analysis of a pebble bed fluoride salt cooled high temperature nuclear reactor (PB-FHR), currently under development in the United States at the university and national laboratories level. In the context of the phenomena identification and ranking table (PIRT) methodology, new tools and approaches are proposed and demonstrated here, which are specifically relevant to technology in the early stages of development, and to analysis of passive safety features. A system decomposition approach is proposed. Definition of system functional requirements complements identification and compilation of the current knowledge base for the behavior of the system. Two new graphical tools are developed for ranking of phenomena importance: a phenomena ranking map, and a phenomena identification and ranking matrix (PIRM). The functional requirements established through this methodology were used for the design and optimization of the reactor core, and for the transient analysis and design of the passive natural circulation driven decay heat removal system for the PB-FHR. A numerical modeling approach for heat-generating porous media, with multi-dimensional fluid flow is presented. The application of this modeling approach to the PB-FHR annular pebble bed core cooled by fluoride salt mixtures generated a model that is called Pod. Pod. was used to show the resilience of the PB-FHR core to generation of hot spots or cold spots, due to the effect of buoyancy on the flow and temperature distribution in the packed bed. Pod. was used to investigate the PB-FHR response to ATWS transients. Based on the functional requirements for the core, Pod. was used to generate an optimized design of the flow distribution in the core. An analysis of natural circulation loops cooled by single-phase Boussinesq fluids is presented here, in the context of reactor design that relies on natural circulation decay heat removal, and design of scaled experiments. The scaling arguments are established for a transient natural circulation loop, for loops that have long fluid residence time, and negligible contribution of fluid inertia to the momentum equation. The design of integral effects tests for the loss of forced circulation (LOFC) for PB-FHR is discussed. The special case of natural circulation decay heat removal from a pebble bed reactor was analyzed. A way to define the Reynolds number in a multi-dimensional pebble bed was identified. The scaling methodology for replicating pebble bed friction losses using an electrically resistance heated annular pipe and a needle valve was developed. The thermophysical properties of liquid fluoride salts lead to design of systems with low flow velocities, and hence long fluid residence times. A comparison among liquid coolants for the performance of steady state natural circulation heat removal from a pebble bed was performed. Transient natural circulation experimental data with simulant fluids for fluoride salts is given here. The low flow velocity and the relatively high viscosity of the fluoride salts lead to low Reynolds number flows, and a low Reynolds number in conjunction with a sufficiently high coefficient of thermal expansion makes the system susceptible to local buoyancy effects Experiments indicate that slow exchange of stagnant fluid in static legs can play a significant role in the transient response of natural circulation loops. The effect of non-linear temperature profiles on the hot or cold legs or other segments of the flow loop, which may develop during transient scenarios, should be considered when modeling the performance of natural circulation loops. The data provided here can be used for validation of the application of thermal-hydraulic systems codes to the modeling of heat removal by natural circulation with liquid fluoride salts and its simulant fluids.

A new airborne laser rangefinder dynamic target simulator for non-stationary environment

NASA Astrophysics Data System (ADS)

Ma, Pengge; Pang, Dongdong; Yi, Yang

2017-11-01

For the non-stationary environment simulation in laser range finder product testing, a new dynamic target simulation system is studied. First of all, the three-pulsed laser ranging principle, laser target signal composition and mathematical representation are introduced. Then, the actual nonstationary working environment of laser range finder is analyzed, and points out that the real sunshine background light clutter and target shielding effect in laser echo become the main influencing factors. After that, the dynamic laser target signal simulation method is given. Eventlly, the implementation of automatic test system based on arbitrary waveform generator is described. Practical application shows that the new echo signal automatic test system can simulate the real laser ranging environment of laser range finder, and is suitable for performance test of products.

An All-Solid-State High Repetiton Rate Titanium:Sapphire Laser System For Resonance Ionization Laser Ion Sources

NASA Astrophysics Data System (ADS)

Mattolat, C.; Rothe, S.; Schwellnus, F.; Gottwald, T.; Raeder, S.; Wendt, K.

2009-03-01

On-line production facilities for radioactive isotopes nowadays heavily rely on resonance ionization laser ion sources due to their demonstrated unsurpassed efficiency and elemental selectivity. Powerful high repetition rate tunable pulsed dye or Ti:sapphire lasers can be used for this purpose. To counteract limitations of short pulse pump lasers, as needed for dye laser pumping, i.e. copper vapor lasers, which include high maintenance and nevertheless often only imperfect reliability, an all-solid-state Nd:YAG pumped Ti:sapphire laser system has been constructed. This could complement or even replace dye laser systems, eliminating their disadvantages but on the other hand introduce shortcomings on the side of the available wavelength range. Pros and cons of these developments will be discussed.

Precise femtosecond laser ablation of dental hard tissue: preliminary investigation on adequate laser parameters

NASA Astrophysics Data System (ADS)

Hikov, Todor; Pecheva, Emilia; Montgomery, Paul; Antoni, Frederic; Leong-Hoi, Audrey; Petrov, Todor

2017-01-01

This work aims at evaluating the possibility of introducing state-of-the-art commercial femtosecond laser system in restorative dentistry by maintaining well-known benefits of lasers for caries removal, but also in overcoming disadvantages such as thermal damage of irradiated substrate. Femtosecond ablation of dental hard tissue is investigated by changing the irradiation parameters (pulsed laser energy, scanning speed and pulse repetition rate), assessed for enamel and dentin. The femtosecond laser system used in this work may be suitable for cavity preparation in dentin and enamel, due to the expected effective ablation and low temperature increase when using ultra short laser pulses. If adequate laser parameters are selected, this system seems to be promising for promoting a laser-assisted, minimally invasive approach in restorative dentistry.

Injection locking of a high power ultraviolet laser diode for laser cooling of ytterbium atoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hosoya, Toshiyuki; Miranda, Martin; Inoue, Ryotaro

2015-07-15

We developed a high-power laser system at a wavelength of 399 nm for laser cooling of ytterbium atoms with ultraviolet laser diodes. The system is composed of an external cavity laser diode providing frequency stabilized output at a power of 40 mW and another laser diode for amplifying the laser power up to 220 mW by injection locking. The systematic method for optimization of our injection locking can also be applied to high power light sources at any other wavelengths. Our system does not depend on complex nonlinear frequency-doubling and can be made compact, which will be useful for providing light sources formore » laser cooling experiments including transportable optical lattice clocks.« less

Handling And Safety Aspects Of Fiber Optic Laser Beam Delivery Systems

NASA Astrophysics Data System (ADS)

Schonborn, K.-H.; Wodrich, W.

1988-06-01

Using lasers for therapeutic applications is getting more and more accepted. In ophthalmology Ar-lasers for intraocular applications are quite common. The Nd:YAG-laser is used as a high power tool in connection with silica fibers for different extracorporal and intracorporal applications. The CO2-laser is the cutting laser, one problem being the beam transmission: The state of the art in fibers is not sufficient up to now. Because of the high power used safety against laser radiation hazard is of great importance. The safety in laser use is primarily dependent on the surgeons cautiousness, e.g. using laser protection goggels, observing that the spot of the aiming beam is present etc. On the other hand the laser and fiber system has to be inherently safe by appropriate technical means as far as possible. An additional aspect adding to safety is the handling: With easier system handling less attention of the surgeon is necessary for driving the apparatus. Thus he can concentrate on the patient and on the procedure. In considering the fiber system one important point in handling and safety is the coupling of the fiber to the laser head. The development philosophy in this coupling may be divided into two groups: - one is trying to use standard connectors which were initially developed for data transmission; - the other is using special connectors. One example of the first group is the guiding of the laser beam from the Ar-laser to the slit-lamp in ophtalmology. Here the well-known F-SMA connectors together with a special fiber with adapted numerical aperture are used. The advantage of such a system is the low price of the connector. For high power lasers such as the clinical Nd:YAG lasers with 40 to 150 W those connectors are not suitable. Up to now every laser manufacturer developed his own connector system in this field.

Solid-state-based laser system as a replacement for Ar⁺ lasers.

PubMed

Beck, Tobias; Rein, Benjamin; Sörensen, Fabian; Walther, Thomas

2016-09-15

We report on a solid-state-based laser system at 1028 nm. The light is generated by a diode laser seeded ytterbium fiber amplifier. In two build-up cavities, its frequency is doubled and quadrupled to 514 nm and 257 nm, respectively. At 514 nm, the system delivers up to 4.7 W of optical power. In the fourth harmonic, up to 173 mW are available limited by the nonlinear crystal. The frequency of the laser is mode-hop-free tunable by 16 GHz in 10 ms in the UV. Therefore, the system is suitable as a low maintenance, efficient, and tunable narrowband replacement for frequency doubled Ar⁺ laser systems.

A Forecast Skill Comparison between CliPAS One-Tier and Two-Tier Hindcast Experiments

NASA Astrophysics Data System (ADS)

Lee, J.; Wang, B.; Kang, I.

2006-05-01

A 24-year (1981-2004) MME hindcast experimental dataset is produced under the "Climate Prediction and Its Application to Society" (CliPAS) project sponsored by Korean Meteorological Administration (KMA). This dataset consists of 5 one-tier model systems from National Aeronautics and Space Administration (NASA), National Center for Environmental Prediction (NCEP), Frontier Research Center for Global Change (FRCGC), Seoul National University (SNU), and University of Hawaii (UH) and 5 two-tier model systems from Florida State University (FSU), Geophysical Fluid Dynamic Lab (GFDL), SNU, and UH. Multi-model Ensemble (MME) Forecast skills of seasonal precipitation and atmospheric circulation are compared between CliPAS one-tier and two-tier hindcast experiments for seasonal mean precipitation and atmospheric circulation. For winter prediction, two-tier MME has a comparable skill to one-tier MME. However, it is demonstrated that in the Asian-Australian monsoon (A-AM) heavy precipitation regions, one-tier systems are superior to two-tier systems in summer season. The reason is that inclusion of the local warm pool- monsoon interaction in the one-tier system improves the ENSO teleconnection with monsoon regions. Both one-tier and two-tier MME fail to predict Indian monsoon circulation, while they have a significantly good skill for the broad scale monsoon circulation defined by Webster and Yang index. One-tier system has a much better skill to predict the monsoon circulation over the western North pacific where air-sea interaction plays an important role than two-tier system.

Liver failure induces a systemic inflammatory response. Prevention by recombinant N-terminal bactericidal/permeability-increasing protein.

PubMed Central

Boermeester, M. A.; Houdijk, A. P.; Meyer, S.; Cuesta, M. A.; Appelmelk, B. J.; Wesdorp, R. I.; Hack, C. E.; Van Leeuwen, P. A.

1995-01-01

The observed increased susceptibility of patients with fulminant hepatic failure for local and systemic infections has been hypothesized to be due to a failure for the hepatic clearance function and subsequent leaking of endogenous endotoxins into the systemic circulation. However, experimental evidence for such a systemic inflammation during liver failure due to endogenous endotoxemia is lacking. Therefore, we designed a study to clarify whether circulating endotoxins due to liver failure could lead to the development of systemic inflammations. In a rat model for liver failure induced by a two-thirds partial hepatectomy, we evaluated the course of circulating tumor necrosis factor and interleukin-6, changes in blood chemistry and hemodynamics, and histopathological changes in the lungs. Partially hepatectomized animals, but not sham-operated animals, demonstrated cardiac failure, increased levels of creatinin and urea, metabolic acidosis, high plasma levels of tumor necrosis factor and interleukin-6, and an influx of PMNs in the lungs-together indicating the development of a systemic inflammatory response. Continuous infusion of recombinant N-terminal bactericidal/permeability-increasing protein (rBPI23), a well described endotoxin-neutralizing protein, prevented these inflammatory reactions. Ex vivo experiments with rat plasma samples confirmed the presence of circulating endotoxins in partially hepatectomized rats as opposed to those treated with rBPI23. Thus, our results indicate that the early phase of liver failure induces a systemic inflammatory response triggered by circulating endotoxins, which can be prevented by perioperative infusion of rBPI23. Images Figure 2 PMID:7485405

Construction and Calibration of a Difference Frequency Laser Spectrometer and New THZ Frequency Measurements of water and Ammonia

NASA Technical Reports Server (NTRS)

Pearson, J. C.; Pickett, Herbert M.; Chen, Pin; Matsuura, Shuji; Blake, Geoffry A.

1999-01-01

A three laser system based on 852nm DBR lasers has been constructed and used to generate radiation in the 750 GHz to 1600 GHz frequency region. The system works by locking two of the three lasers to modes of an ultra low expansion Fabry-Perot cavity. The third laser is offset locked to one of the cavity locked lasers with conventional microwave techniques. The signal from the offset laser and the other cavity locked laser are injected into a Master Oscillator Power Amplifier (MOPA), amplified and focused on a low temperature grown GaAs photomixer, which radiates the difference frequency. The system has been calibrated with molecular lines to better than one part in 10(exp 7). In this paper we present the application of this system to the v(sub 2) in inversion band of Ammonia and the ground and v(sub 2) states of water. A discussion of the system design, the calibration and the new spectral measurements will be presented.

Designation of a polarization-converting system and its enhancement of double-frequency efficiency

NASA Astrophysics Data System (ADS)

Wang, Peng; Li, Xiao; Shang, YaPing; Xu, XiaoJun

2015-08-01

A polarization-converting system is designed by using axicons and wave plate transforming naturally polarized laser to linearly polarized laser at real time to resolve difficulties of generating high-power linearly polarized laser. The energy conversion efficiency reaches 96.9% with an enhancement of extinction ratio from 29.7% to 98%. The system also keeps excellent far field divergence. In the one-way SHG experiment the double frequency efficiency reached 4.32% using the generated linearly polarized laser, much higher than that of the naturally polarized laser but lower than that of the linearly polarized laser from PBS. And the phenomenon of the SHG experiment satisfies the principle of phase matching. The experiment proves that this polarization-converting system will not affect laser structure which controls easily and needs no feedback and controlling system with stable and reliable properties at the same time. It can absolutely be applied to the polarization-conversion of high power laser and enhance the SHG efficiency and the energy efficiency.

On-Chip Laser-Power Delivery System for Dielectric Laser Accelerators

NASA Astrophysics Data System (ADS)

Hughes, Tyler W.; Tan, Si; Zhao, Zhexin; Sapra, Neil V.; Leedle, Kenneth J.; Deng, Huiyang; Miao, Yu; Black, Dylan S.; Solgaard, Olav; Harris, James S.; Vuckovic, Jelena; Byer, Robert L.; Fan, Shanhui; England, R. Joel; Lee, Yun Jo; Qi, Minghao

2018-05-01

We propose an on-chip optical-power delivery system for dielectric laser accelerators based on a fractal "tree-network" dielectric waveguide geometry. This system replaces experimentally demanding free-space manipulations of the driving laser beam with chip-integrated techniques based on precise nanofabrication, enabling access to orders-of-magnitude increases in the interaction length and total energy gain for these miniature accelerators. Based on computational modeling, in the relativistic regime, our laser delivery system is estimated to provide 21 keV of energy gain over an acceleration length of 192 μ m with a single laser input, corresponding to a 108-MV/m acceleration gradient. The system may achieve 1 MeV of energy gain over a distance of less than 1 cm by sequentially illuminating 49 identical structures. These findings are verified by detailed numerical simulation and modeling of the subcomponents, and we provide a discussion of the main constraints, challenges, and relevant parameters with regard to on-chip laser coupling for dielectric laser accelerators.

Miniature Gas-Circulating Machine

NASA Technical Reports Server (NTRS)

Swift, Walter L.; Valenzuela, Javier A.; Sixsmith, Herbert; Nutt, William E.

1993-01-01

Proposed gas-circulating machine consists essentially of centrifugal pump driven by induction motor. Noncontact bearings suppress wear and contamination. Used to circulate helium (or possibly hydrogen or another gas) in regeneration sorption-compressor refrigeration system aboard spacecraft. Also proves useful in terrestrial applications in which long life, reliability, and low contamination essential.

76 FR 12217 - Exempt Discretionary Program Grants (Section 5309) for Urban Circulator Systems

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-04

... redevelopment of urban spaces into walkable mixed use, high density environments. FOR FURTHER INFORMATION... development. FTA's approval to advance the Urban Circulator projects through project development and grant... urban circulators shall be required to submit information that describes the impact of the urban...

Generation of 369.4 nm Radiation by Efficient Doubling of a Diode Laser

NASA Technical Reports Server (NTRS)

Williams, A.; Seidel, D. J.; Maleki, J.

1993-01-01

A resonant cavity second harmonic generation system has been developed to produce 369.4 nm radiation from a 738.8 nm diode laser with 10 mW nominal output power. This system utilizes a polarization technique to lock the cavity to the laser frequency. In this paper we report on an evaluation of the system using a Titanium:Sapphire laser as the input source, and preliminary results with a diode laser source. To our knowledge, this is the deepest uv light ever produced by frequency-doubling a diode laser.

Beam-guidance optics for high-power fiber laser systems

NASA Astrophysics Data System (ADS)

Mohring, Bernd; Tassini, Leonardo; Protz, Rudolf; Zoz, Jürgen

2013-05-01

The realization of a high-energy laser weapon system by coupling a large number of industrial high-power fiber lasers is investigated. To perform the combination of the individual beams of the different fiber lasers within the optical path of the laser weapon, a special optical set-up is used. Each optical component is realized either as reflective component oras refractive optics. Both possibilities were investigated by simulations and experiments. From the results, the general aspects for the layout of the beam-guidance optics for a high-power fiber laser system are derived.

Laser diode technology for coherent communications

NASA Technical Reports Server (NTRS)

Channin, D. J.; Palfrey, S. L.; Toda, M.

1989-01-01

The effect of diode laser characteristics on the overall performance capabilities of coherent communication systems is discussed. In particular, attention is given to optical performance issues for diode lasers in coherent systems, measurements of key performance parameters, and optical requirements for coherent single-channel and multichannel communication systems. The discussion also covers limitations imposed by diode laser optical performance on multichannel system capabilities and implications for future developments.

Noninvasive and label-free detection of circulating melanoma cells by in vivo photoacoustic flow cytometry

NASA Astrophysics Data System (ADS)

Yang, Ping; Liu, Rongrong; Niu, Zhenyu; Suo, Yuanzhen; He, Hao; Wei, Xunbin

2015-03-01

Melanoma is a malignant tumor of melanocytes. Circulating melanoma cell has high light absorption due to melanin highly contained in melanoma cells. This property is employed for the detection of circulating melanoma cell by in vivo photoacoustic flow cytometry (PAFC). PAFC is based on photoacoustic effect. Compared to in vivo flow cytometry based on fluorescence, PAFC can employ high melanin content of melanoma cells as endogenous biomarkers to detect circulating melanoma cells in vivo. In our research, we developed in vitro experiments to prove the ability of PAFC system of detecting PA signals from melanoma cells. For in vivo experiments, we constructed a model of melanoma tumor bearing mice by inoculating highly metastatic murine melanoma cancer cells B16F10 with subcutaneous injection. PA signals were detected in the blood vessels of mouse ears in vivo. By counting circulating melanoma cells termly, we obtained the number variation of circulating melanoma cells as melanoma metastasized. Those results show that PAFC is a noninvasive and label-free method to detect melanoma metastases in blood or lymph circulation. Our PAFC system is an efficient tool to monitor melanoma metastases, cancer recurrence and therapeutic efficacy.

Control of Hazards to Health From Laser Radiation

DTIC Science & Technology

2006-01-01

compared to the calculated AEL. (2) Optically aided viewing. Viewing a laser beam with optical aids (other than ordinary eyeglasses or contact lenses ...resonant optical cavity. TB MED 524 8 b. Lenses , mirrors, cooling systems, shutters, and other accessories may be added to the system to obtain...procedures for laser optical systems (for example, mirrors, prisms, and lenses ) that employ Class 2 and Class 3a lasers, it is always good laser safety

Effects of femtosecond laser radiation on the skin

NASA Astrophysics Data System (ADS)

Rogov, P. Yu; Bespalov, V. G.

2016-08-01

A mathematical model of linear and nonlinear processes is presented occurring under the influence of femtosecond laser radiation on the skin. There was held an analysis and the numerical solution of an equation system describing the dynamics of the electron and phonon subsystems were received. The results can be used to determine the maximum permissible levels of energy generated by femtosecond laser systems and the establishment of Russian laser safety standards for femtosecond laser systems.

A Modular Control Platform for a Diode Pumped Alkali Laser

NASA Astrophysics Data System (ADS)

Shapiro, J.; Teare, S.

Many of the difficulties of creating compact, high power laser systems can be overcome if the heat dissipating properties of chemical lasers can be combined with the efficiency of diode lasers. Recently, the novel idea of using solid state diode lasers to pump gaseous gain media, such as is done in diode pumped alkali lasers (DPALs), has been proposed and early experiments have shown promising results. However, a number of technical issues need to be overcome to realize high output power from these lasers. In order to achieve higher power, the efficiency of coupling between pump laser energy and the chemical cell must be increased, and eventually multiple high power diode pumps must be combined and synchronized so that their energy can pump the chemical cell. Additionally, an inter-cavity adaptive optics system may be a requirement to be able to propagate these lasers with high efficiency. DPAL systems are complex and require a significant amount of data fusion and active feedback to control and optimize their performance. There are a wide range of components including pump lasers, gain cells and monitoring points needed to study and refine the overall laser system. In support of this dynamic development environment, we have developed a hardware framework using commercial off the shelf (COTS) components which supports the rapid assembly of functional system blocks into a cohesive integrated system. Critical to this system are a simple communication protocol, industry standard communication pipes (USB, Bluetooth, etc), and flexible high level scripting. Simplifying the integration process has the benefit of allowing flexible "on the fly" modifications to adapt the system as needed and enhance available functionality. The modular nature of the architecture allows scalability and adaptability as more pieces are added to the system. Key components of this system are demonstrated for selected portions of a DPAL system using a USB backbone.

Instrument for fluorescence sensing of circulating cells with diffuse light in mice in vivo.

PubMed

Zettergren, Eric; Vickers, Dwayne; Runnels, Judith; Murthy, Shashi K; Lin, Charles P; Niedre, Mark

2012-03-01

Accurate quantification of circulating cell populations in mice is important in many areas of preclinical biomedical research. Normally, this is done either by extraction and analysis of small blood samples or, more recently, by using microscopy-based in vivo fluorescence flow cytometry. We describe a new technological approach to this problem using detection of diffuse fluorescent light from relatively large blood vessels in vivo. The diffuse fluorescence flow cytometer (DFFC) uses a laser to illuminate a mouse limb and an array of optical fibers coupled to a high-sensitivity photomultiplier tube array operating in photon counting mode to detect weak fluorescence signals from cells. We first demonstrate that the DFFC instrument is capable of detecting fluorescent microspheres and Vybrant-DiD-labeled cells in a custom-made optical flow phantom with similar size, optical properties, linear flow rates, and autofluorescence as a mouse limb. We also present preliminary data demonstrating that the DFFC is capable of detecting circulating cells in nude mice in vivo. In principle, this device would allow interrogation of the whole blood volume of a mouse in minutes, with sensitivity improvement by several orders of magnitude compared to current approaches. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).

Laser system using regenerative amplifier

DOEpatents

Emmett, John L. [Pleasanton, CA

1980-03-04

High energy laser system using a regenerative amplifier, which relaxes all constraints on laser components other than the intrinsic damage level of matter, so as to enable use of available laser system components. This can be accomplished by use of segmented components, spatial filters, at least one amplifier using solid state or gaseous media, and separated reflector members providing a long round trip time through the regenerative cavity, thereby allowing slower switching and adequate time to clear the spatial filters, etc. The laser system simplifies component requirements and reduces component cost while providing high energy output.

29 CFR 1910.126 - Additional requirements for special dipping and coating operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... sprinklers; or (ii) An automatic fire-extinguishing system conforming to the requirements of subpart L of... the alarm set point, you must equip the tank with a circulating cooling system. (5) If the tank has a bottom drain, the bottom drain may be combined with the oil-circulating system. (6) You must not use air...

29 CFR 1910.126 - Additional requirements for special dipping and coating operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... sprinklers; or (ii) An automatic fire-extinguishing system conforming to the requirements of subpart L of... the alarm set point, you must equip the tank with a circulating cooling system. (5) If the tank has a bottom drain, the bottom drain may be combined with the oil-circulating system. (6) You must not use air...

Temperature field study of hot water circulation pump shaft system

NASA Astrophysics Data System (ADS)

Liu, Y. Y.; Kong, F. Y.; Daun, X. H.; Zhao, R. J.; Hu, Q. L.

2016-05-01

In the process of engineering application under the condition of hot water circulation pump, problems of stress concentration caused by the temperature rise may happen. In order to study the temperature field in bearing and electric motor chamber of the hot water circulation pump and optimize the structure, in present paper, the model of the shaft system is created through CREO. The model is analyzed by ANSYS workbench, in which the thermal boundary conditions are applied to calculate, which include the calorific values from the bearings, the thermal loss from electric motor and the temperature from the transporting medium. From the result, the finite element model can reflect the distribution of thermal field in hot water circulation pump. Further, the results show that the maximum temperature locates in the bearing chamber.The theoretical guidance for the electric motor heat dissipation design of the hot water circulation pump can be achieved.

Analysis of detection performance of multi band laser beam analyzer

NASA Astrophysics Data System (ADS)

Du, Baolin; Chen, Xiaomei; Hu, Leili

2017-10-01

Compared with microwave radar, Laser radar has high resolution, strong anti-interference ability and good hiding ability, so it becomes the focus of laser technology engineering application. A large scale Laser radar cross section (LRCS) measurement system is designed and experimentally tested. First, the boundary conditions are measured and the long range laser echo power is estimated according to the actual requirements. The estimation results show that the echo power is greater than the detector's response power. Secondly, a large scale LRCS measurement system is designed according to the demonstration and estimation. The system mainly consists of laser shaping, beam emitting device, laser echo receiving device and integrated control device. Finally, according to the designed lidar cross section measurement system, the scattering cross section of target is simulated and tested. The simulation results are basically the same as the test results, and the correctness of the system is proved.

Laser rocket system analysis

NASA Technical Reports Server (NTRS)

Jones, W. S.; Forsyth, J. B.; Skratt, J. P.

1979-01-01

The laser rocket systems investigated in this study were for orbital transportation using space-based, ground-based and airborne laser transmitters. The propulsion unit of these systems utilizes a continuous wave (CW) laser beam focused into a thrust chamber which initiates a plasma in the hydrogen propellant, thus heating the propellant and providing thrust through a suitably designed nozzle and expansion skirt. The specific impulse is limited only by the ability to adequately cool the thruster and the amount of laser energy entering the engine. The results of the study showed that, with advanced technology, laser rocket systems with either a space- or ground-based laser transmitter could reduce the national budget allocated to space transportation by 10 to 345 billion dollars over a 10-year life cycle when compared to advanced chemical propulsion systems (LO2-LH2) of equal capability. The variation in savings depends upon the projected mission model.

Planning an Integrated On-Line Library system (IOLS)

DTIC Science & Technology

1989-03-01

Logical Workflow for Circulation of Library Materials ............. 14 Figure 9. Detail of Circulation of Libary Materials ...................... 15...Operating Honolulu, HI 96826 System (808) 947-4441 DATA RESEARCH ASSOCIATES, Inc. (ATLAS) 9270 Olive Blvd. St. Louis, MO 01775 DIGITAL EQUIPMENT CORP... DIGITAL EQUIPMENT CORP. Stow, MA 01775 (617) 897-7163 EYRING LIBRARY SYSTEMS (CARL) 5280 S. West, Suite E260 Salt Lake City, UT 84107 TANDEM SYSTEMS

In situ heat treatment process utilizing a closed loop heating system

DOEpatents

Vinegar, Harold J.; Nguyen, Scott Vinh

2010-12-07

Systems and methods for an in situ heat treatment process that utilizes a circulation system to heat one or more treatment areas are described herein. The circulation system may use a heated liquid heat transfer fluid that passes through piping in the formation to transfer heat to the formation. In some embodiments, the piping may be positioned in at least two of the wellbores.

Pedestal cleaning for high laser pulse contrast ratio with a 100 TW class laser system.

PubMed

Fourmaux, S; Payeur, S; Buffechoux, S; Lassonde, P; St-Pierre, C; Martin, F; Kieffer, J C

2011-04-25

Laser matter interaction at relativistic intensities using 100 TW class laser systems or higher is becoming more and more widespread. One of the critical issues of such laser systems is to let the laser pulse interact at high intensity with the solid target and avoid any pre-plasma. Thus, a high Laser Pulse Contrast Ratio (LPCR) parameter is of prime importance. We present the LPCR characterization of a high repetition 100 TW class laser system. We demonstrate that the generated Amplified Spontaneous Emission (ASE) degrades the overall LPCR performance. We propose a simple way to clean the pulse after the first amplification stage by introducing a solid state saturable absorber which results in a LPCR improvement to better than 10(10) with only a 30% energy loss at a 10 Hz repetition rate. We finally correlated this cleaning method with experimental results.

Using real time traveler demand data to optimize commuter rail feeder systems.

DOT National Transportation Integrated Search

2012-08-01

"This report focuses on real time optimization of the Commuter Rail Circulator Route Network Design Problem (CRCNDP). The route configuration of the circulator system where to stop and the route among the stops is determined on a real-time ba...

Free-space laser communication technologies II; Proceedings of the Meeting, Los Angeles, CA, Jan. 15-17, 1990

NASA Technical Reports Server (NTRS)

Begley, David L. (Editor); Seery, Bernard D. (Editor)

1990-01-01

Various papers on free-space laser communication technologies are presented. Individual topics addressed include: optical intersatellite link experiment between the earth station and ETS-VI, the Goddard optical communications program, technologies and techniques for lasercom terminal size, weight, and cost reduction, laser beam acquisition and tracking system for ETS-VI laser communication equipment, analog dividers for acquisition and tracking signal normalization, fine pointing mechanism using multilayered piezoelectric actuator for optical ISL system, analysis of SILEX tracking sensor performance, new telescope concept for space communication, telescope considered as a very high gain antenna, design of compact transceiver optical systems for optical intersatellite links, ultralightweight optics for laser communications, highly sensitive measurement method for stray light and retroreflected light, depolarization effects on free space laser transceiver communication systems, in-orbit measurements of microaccelerations of ESA's communication satellite Olympus, high-performance laser diode transmitter for optical free space communication, diode-pumped Nd:host laser transmitter for intersatellite optical communications, single-frequency diode-pumped laser for free-space communication.

Strongly aligned gas-phase molecules at free-electron lasers

DOE PAGES

Kierspel, Thomas; Wiese, Joss; Mullins, Terry; ...

2015-09-16

Here, we demonstrate a novel experimental implementation to strongly align molecules at full repetition rates of free-electron lasers. We utilized the available in-house laser system at the coherent x-ray imaging beamline at the linac coherent light source. Chirped laser pulses, i.e., the direct output from the regenerative amplifier of the Ti:Sa chirped pulse amplification laser system, were used to strongly align 2, 5-diiodothiophene molecules in a molecular beam. The alignment laser pulses had pulse energies of a few mJ and a pulse duration of 94 ps. A degree of alignment ofmore » $$\\langle {\\mathrm{cos}}^{2}{\\theta }_{2{\\rm{D}}}\\rangle =0.85$$ was measured, limited by the intrinsic temperature of the molecular beam rather than by the available laser system. With the general availability of synchronized chirped-pulse-amplified near-infrared laser systems at short-wavelength laser facilities, our approach allows for the universal preparation of molecules tightly fixed in space for experiments with x-ray pulses.« less

High repetition ration solid state switched CO2 TEA laser employed in industrial ultrasonic testing of aircraft parts

NASA Astrophysics Data System (ADS)

von Bergmann, Hubertus; Morkel, Francois; Stehmann, Timo

2015-02-01

Laser Ultrasonic Testing (UT) is an important technique for the non-destructive inspection of composite parts in the aerospace industry. In laser UT a high power, short pulse probe laser is scanned across the material surface, generating ultrasound waves which can be detected by a second low power laser system and are used to draw a defect map of the part. We report on the design and testing of a transversely excited atmospheric pressure (TEA) CO2 laser system specifically optimised for laser UT. The laser is excited by a novel solid-state switched pulsing system and utilises either spark or corona preionisation. It provides short output pulses of less than 100 ns at repetition rates of up to 1 kHz, optimised for efficient ultrasonic wave generation. The system has been designed for highly reliable operation under industrial conditions and a long term test with total pulse counts in excess of 5 billion laser pulses is reported.

Sensor-based laser ablation for tissue specific cutting: an experimental study.

PubMed

Rupprecht, Stephan; Tangermann-Gerk, Katja; Wiltfang, Joerg; Neukam, Friedrich Wilhelm; Schlegel, Andreas

2004-01-01

The interaction of laser light and tissue causes measurable phenomenons. These phenomenons can be quantified and used to control the laser drilling within a feedback system. Ten halves of dissected minipig jaws were treated with an Er:YAG laser system controlled via a feedback system. Sensor outputs were recorded and analyzed while osteotomy was done. The relative depth of laser ablation was calculated by 3D computed tomography and evaluated histologically. The detected signals caused by the laser-tissue interaction changed their character in a dramatic way after passing the cortical bone layer. The radiological evaluation of 98 laser-ablated holes in the ten halves showed no deeper ablation beyond the cortical layer (mean values: 97.8%). Histologically, no physical damage to the alveolar nerve bundle was proved. The feedback system to control the laser drilling was working exactly for cortical ablation of the bone based on the evaluation of detected and quantified phenomenon related to the laser-tissue interaction.

Research on laser detonation pulse circuit with low-power based on super capacitor

NASA Astrophysics Data System (ADS)

Wang, Hao-yu; Hong, Jin; He, Aifeng; Jing, Bo; Cao, Chun-qiang; Ma, Yue; Chu, En-yi; Hu, Ya-dong

2018-03-01

According to the demand of laser initiating device miniaturization and low power consumption of weapon system, research on the low power pulse laser detonation circuit with super capacitor. Established a dynamic model of laser output based on super capacitance storage capacity, discharge voltage and programmable output pulse width. The output performance of the super capacitor under different energy storage capacity and discharge voltage is obtained by simulation. The experimental test system was set up, and the laser diode of low power pulsed laser detonation circuit was tested and the laser output waveform of laser diode in different energy storage capacity and discharge voltage was collected. Experiments show that low power pulse laser detonation based on super capacitor energy storage circuit discharge with high efficiency, good transient performance, for a low power consumption requirement, for laser detonation system and low power consumption and provide reference light miniaturization of engineering practice.

Dynamically variable spot size laser system

NASA Technical Reports Server (NTRS)

Gradl, Paul R. (Inventor); Hurst, John F. (Inventor); Middleton, James R. (Inventor)

2012-01-01

A Dynamically Variable Spot Size (DVSS) laser system for bonding metal components includes an elongated housing containing a light entry aperture coupled to a laser beam transmission cable and a light exit aperture. A plurality of lenses contained within the housing focus a laser beam from the light entry aperture through the light exit aperture. The lenses may be dynamically adjusted to vary the spot size of the laser. A plurality of interoperable safety devices, including a manually depressible interlock switch, an internal proximity sensor, a remotely operated potentiometer, a remotely activated toggle and a power supply interlock, prevent activation of the laser and DVSS laser system if each safety device does not provide a closed circuit. The remotely operated potentiometer also provides continuous variability in laser energy output.

Improved pulse laser ranging algorithm based on high speed sampling

NASA Astrophysics Data System (ADS)

Gao, Xuan-yi; Qian, Rui-hai; Zhang, Yan-mei; Li, Huan; Guo, Hai-chao; He, Shi-jie; Guo, Xiao-kang

2016-10-01

Narrow pulse laser ranging achieves long-range target detection using laser pulse with low divergent beams. Pulse laser ranging is widely used in military, industrial, civil, engineering and transportation field. In this paper, an improved narrow pulse laser ranging algorithm is studied based on the high speed sampling. Firstly, theoretical simulation models have been built and analyzed including the laser emission and pulse laser ranging algorithm. An improved pulse ranging algorithm is developed. This new algorithm combines the matched filter algorithm and the constant fraction discrimination (CFD) algorithm. After the algorithm simulation, a laser ranging hardware system is set up to implement the improved algorithm. The laser ranging hardware system includes a laser diode, a laser detector and a high sample rate data logging circuit. Subsequently, using Verilog HDL language, the improved algorithm is implemented in the FPGA chip based on fusion of the matched filter algorithm and the CFD algorithm. Finally, the laser ranging experiment is carried out to test the improved algorithm ranging performance comparing to the matched filter algorithm and the CFD algorithm using the laser ranging hardware system. The test analysis result demonstrates that the laser ranging hardware system realized the high speed processing and high speed sampling data transmission. The algorithm analysis result presents that the improved algorithm achieves 0.3m distance ranging precision. The improved algorithm analysis result meets the expected effect, which is consistent with the theoretical simulation.

Laser-Induced Damage Threshold and Certification Procedures for Optical Materials

NASA Technical Reports Server (NTRS)

1997-01-01

This document provides instructions for performing laser-induced-damage-threshold tests and pass-fail certification tests on optical materials used in pulsed-laser systems. The optical materials to which these procedures apply include coated and uncoated optical substrates, laser crystals, Q-switches, polarizers, and other optical components employed in pulsed-laser systems.

DESIGN OF A GAMMA-RAY SOURCE BASED ON INVERSE COMPTON SCATTERING AT THE FAST SUPERCONDUCTING LINAC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mihalcea, D.; Jacobson, B.; Murokh, A.

2016-10-10

A watt-level average-power gamma-ray source is currently under development at the Fermilab Accelerator Science & Technology (FAST) facility. The source is based on the Inverse Compton Scattering of a high-brightness 300-MeV beam against a high-power laser beam circulating in an optical cavity. The back scattered gamma rays are expected to have photon energies up to 1.5 MeV. This paper discusses the optimization of the source, its performances, and the main challenges ahead.

Improving laser system productivity through production line integration

NASA Astrophysics Data System (ADS)

Belforte, David A.

1994-09-01

Thousands of laser systems are employed profitably in a variety of industrial applications. These installations have proved successful for economic and technical reasons. And, in certain applications: ceramic scribing, resistor trimming, sheet metal cutting, and air foil drilling, for example, have become the industry standard. Most of these installations are free standing or, at best, part of an off-line manufacturing cell. Examples of laser systems fully integrated into a production line, where the laser process is synchronized with up and down stream manufacturing operation, are rare. The laser has been under utilized in its potential contribution to production line productivity. Current development in laser beam delivery: multiplexing, beam splitting and other distributed energy concepts make the laser an attractive option for just-in-time manufacturing operations. The reasons for this apparent neglect of the laser's full potential are reviewed in this paper, and suggestions for improvement of this situation are offered. Examples of fully integrated laser systems and their successful implementation are described and a forecast of changes in the way lasers contribute to improved productivity and profitability will be made.

Lasers in endodontics: an overview

NASA Astrophysics Data System (ADS)

Frentzen, Matthias; Braun, Andreas; Koort, Hans J.

2002-06-01

The interest in endodontic use of dental laser systems is increasing. Developing laser technology and a better understanding of laser effects widened the spectrum of possible endodontic indications. Various laser systems including excimer-, argon+-, diode-, Nd:YAG-, Er:YAG- and CO2-lasers are used in pulp diagnosis, treatment of hypersensitivity, pulp capping, sterilization of root canals, root canal shaping and obturation or apicoectomy. With the development of new delivery systems - thin and flexible fibers - for many different wavelengths laser applications in endodontics may increase. Since laser devices are still relatively costly, access to them is limited. Most of the clinical applications are laser assisted procedures such as the removing of pulp remnants and debris or disinfection of infected root canals. The essential question is whether a laser can provide improved treatment over conventional care. To perform laser therapy in endodontics today different laser types with adopted wavelengths and pulse widths are needed, each specific to a particular application. Looking into the future we will need endodontic laser equipment providing optimal laser parameters for different treatment modalities. Nevertheless, the quantity of research reports from the last decade promises a genuine future for lasers in endodontics.

Comparison between sequentional treatment with diode and alexandrite lasers versus alexandrite laser alone in the treatment of hirsutism.

PubMed

Nilforoushzadeh, Mohammad Ali; Naieni, Farahnaz Fatemi; Siadat, Amir Hossein; Rad, Leila

2011-11-01

Laser systems that are commonly used for the treatment of hirsutism include the ruby laser (694 nm), the diode laser (800 nm), the alexandrite laser (755 nm) and the Nd:YAG laser (1084 nm). The diode laser and alexandrite laser are considered effective in treatment of hirsutism in dark-skinned patients. The response of hairs to these laser systems is variable and not complete. In this study, we compared the efficacy of these two laser systems for permanent hair removal. This was a randomized, controlled clinical trial that was performed with women of the age range 15-45 years old. After obtaining informed consent, the samples were randomized into two groups using random allocation software. The first group was treated with alexandrite laser alone (four sessions, two months apart). The second group was treated sequentially with diode laser for the first two sessions and alexandrite laser for the next two sessions. Overall, 111 patients (57 patients in the alexandrite laser group and 54 patients in the sequential diode-alexandrite laser group) were evaluated. There was no significant difference regarding mean of hair reduction between the two groups during the courses of treatment. Except for the first session, there was no significant difference regarding percent of patient satisfaction between the two groups (P value >0.05). Comparison between the two groups showed no significant difference one month, three months and six months after the last treatment (P value >0.05). Regarding the results of our study, there is no significant difference between sequential treatment with diode and alexandrite lasers versus alexandrite laser alone in the treatment of hirsutism. We suggest that in further studies, the efficacy of sequential treatment with other laser systems is evaluated against single treatment methods.

Leading Edge. Volume 7, Issue Number 4, 2012

DTIC Science & Technology

2012-01-01

system . The electric field emitted from the throat of this system was so high that a special bag of high- voltage gas was needed until the radiating...and the Sea-Lite beam director. By 1990, this building-sized system demonstrated shooting boosters, missiles in flight, and superson - ic vehicles...only success- ful laser weapon system developed by the Navy prior to the Navy Laser Weapon System (LaWS).3 Gas Lasers Gas lasers are a type of

A new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array

NASA Astrophysics Data System (ADS)

Xia, Wenze; Ma, Yayun; Han, Shaokun; Wang, Yulin; Liu, Fei; Zhai, Yu

2018-06-01

One of the most important goals of research on three-dimensional nonscanning laser imaging systems is the improvement of the illumination system. In this paper, a new three-dimensional nonscanning laser imaging system based on the illumination pattern of a point-light-source array is proposed. This array is obtained using a fiber array connected to a laser array with each unit laser having independent control circuits. This system uses a point-to-point imaging process, which is realized using the exact corresponding optical relationship between the point-light-source array and a linear-mode avalanche photodiode array detector. The complete working process of this system is explained in detail, and the mathematical model of this system containing four equations is established. A simulated contrast experiment and two real contrast experiments which use the simplified setup without a laser array are performed. The final results demonstrate that unlike a conventional three-dimensional nonscanning laser imaging system, the proposed system meets all the requirements of an eligible illumination system. Finally, the imaging performance of this system is analyzed under defocusing situations, and analytical results show that the system has good defocusing robustness and can be easily adjusted in real applications.

[Nailfold capillaroscopy and blood flow laser-doppler analysis of the microvascular damage in systemic sclerosis: preliminary results].

PubMed

Secchi, M E; Sulli, A; Pizzorni, C; Cutolo, M

2009-01-01

Systemic sclerosis (SSc) is characterized by altered microvascular structure and function. Nailfold videocapillaroscopy (NVC) is the tool to evaluate capillary morphological structure and laser-Doppler Blood flowmetry (LDF) can be used to estimate cutaneous blood flow of microvessels. The aim of this study was to investigate possible relationships between capillary morphology and blood flow in SSc. Twenty-seven SSc patients and 12 healthy subjects were enrolled. SSc microvascular involvement, as evaluated by NVC, was classified in three different patterns ("Early", "Active", "Late"). LDF analysis was performed at the II, III, IV, V hand fingers in both hands and both at cutaneous temperature and at 36 degrees C. Statistical evaluation was carried out by non-parametric procedures. Blood flow was found significantly lower in SSc patients when compared with healthy subjects (p<0.05). The heating of the probe to 36 degrees C induced a significant increase in peripheral blood flow in all subjects compared to baseline (p <0.05), however, the amount of variation was significantly lower in patients with SSc, compared with healthy controls (p <0.05). The SSc patients with NVC "Late" pattern, showed lower values of peripheral blood flow than patients with NVC "Active" or "Early" patterns (p<0.05). Moreover, a negative correlation between the tissue perfusion score and the progression of the SSc microangiopathy was observed, as well as between the tissue perfusion and the duration of the Raynaud's phenomenon (p <0.03). LDF can be employed to evaluate blood perfusion in the microvascular circulation in SSc patients. The blood flow changes observed with the LDF seem to correlate with the severity of microvascular damage in SSc as detected by NVC.

Near-Continuous Isotopic Characterization of Soil N2O Fluxes from Maize Production

NASA Astrophysics Data System (ADS)

Anex, R. P.; Francis Clar, J.

2015-12-01

Isotopomer ratios of N2O and especially intramolecular 15N site preference (SP) have been proposed as indicators of the sources of N2O and for providing insight into the contributions of different microbial processes. Current knowledge, however, is mainly based on pure culture studies and laboratory flask studies using mass spectrometric analysis. Recent development of laser spectroscopic methods has made possible high-precision, in situ measurements. We present results from a maize production field in Columbia County, Wisconsin, USA. Data were collected from the fertilized maize phase of a maize-soybean rotation. N2O mole fractions and isotopic composition were determined using an automatic gas flux measurement system comprising a set of custom-designed automatic chambers, circulating gas paths and an OA-ICOS N2O Isotope Analyzer (Los Gatos Research, Inc., Model 914-0027). The instrument system allows for up to 15 user programmable soil gas chambers. Wide dynamic range and parts-per-billion precision of OA-ICOS laser absorption instrument allows for extremely rapid estimation of N2O fluxes. Current operational settings provide measurements of N2O and its isotopes every 20 seconds with a precision of 0.1 ± 0.050 PPB. Comparison of measurements from four chambers (two between row and two in-row) show very different aggregate N2O flux, but SP values suggest similar sources from nitrifier denitrification and incomplete bacterial denitrification. SP values reported are being measured throughout the current growing season. To date, the majority of values are consistent with an origin from bacterial denitrification and coincide with periods of high water filled pore space.

Thick SS316 materials TIG welding development activities towards advanced fusion reactor vacuum vessel applications

NASA Astrophysics Data System (ADS)

Kumar, B. Ramesh; Gangradey, R.

2012-11-01

Advanced fusion reactors like ITER and up coming Indian DEMO devices are having challenges in terms of their materials design and fabrication procedures. The operation of these devices is having various loads like structural, thermo-mechanical and neutron irradiation effects on major systems like vacuum vessel, divertor, magnets and blanket modules. The concept of double wall vacuum vessel (VV) is proposed in view of protecting of major reactor subsystems like super conducting magnets, diagnostic systems and other critical components from high energy 14 MeV neutrons generated from fusion plasma produced by D-T reactions. The double walled vacuum vessel is used in combination with pressurized water circulation and some special grade borated steel blocks to shield these high energy neutrons effectively. The fabrication of sub components in VV are mainly used with high thickness SS materials in range of 20 mm- 60 mm of various grades based on the required protocols. The structural components of double wall vacuum vessel uses various parts like shields, ribs, shells and diagnostic vacuum ports. These components are to be developed with various welding techniques like TIG welding, Narrow gap TIG welding, Laser welding, Hybrid TIG laser welding, Electron beam welding based on requirement. In the present paper the samples of 20 mm and 40 mm thick SS 316 materials are developed with TIG welding process and their mechanical properties characterization with Tensile, Bend tests and Impact tests are carried out. In addition Vickers hardness tests and microstructural properties of Base metal, Heat Affected Zone (HAZ) and Weld Zone are done. TIG welding application with high thick SS materials in connection with vacuum vessel requirements and involved criticalities towards welding process are highlighted.

Feature-oriented regional modeling and simulations in the Gulf of Maine and Georges Bank

NASA Astrophysics Data System (ADS)

Gangopadhyay, Avijit; Robinson, Allan R.; Haley, Patrick J.; Leslie, Wayne G.; Lozano, Carlos J.; Bisagni, James J.; Yu, Zhitao

2003-03-01

The multiscale synoptic circulation system in the Gulf of Maine and Georges Bank (GOMGB) region is presented using a feature-oriented approach. Prevalent synoptic circulation structures, or 'features', are identified from previous observational studies. These features include the buoyancy-driven Maine Coastal Current, the Georges Bank anticyclonic frontal circulation system, the basin-scale cyclonic gyres (Jordan, Georges and Wilkinson), the deep inflow through the Northeast Channel (NEC), the shallow outflow via the Great South Channel (GSC), and the shelf-slope front (SSF). Their synoptic water-mass ( T- S) structures are characterized and parameterized in a generalized formulation to develop temperature-salinity feature models. A synoptic initialization scheme for feature-oriented regional modeling and simulation (FORMS) of the circulation in the coastal-to-deep region of the GOMGB system is then developed. First, the temperature and salinity feature-model profiles are placed on a regional circulation template and then objectively analyzed with appropriate background climatology in the coastal region. Furthermore, these fields are melded with adjacent deep-ocean regional circulation (Gulf Stream Meander and Ring region) along and across the SSF. These initialization fields are then used for dynamical simulations via the primitive equation model. Simulation results are analyzed to calibrate the multiparameter feature-oriented modeling system. Experimental short-term synoptic simulations are presented for multiple resolutions in different regions with and without atmospheric forcing. The presented 'generic and portable' methodology demonstrates the potential of applying similar FORMS in many other regions of the Global Coastal Ocean.

Two phase gap cooling of an electrical machine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shoykhet, Boris A.

2016-10-04

An electro-dynamic machine has a rotor and stator with a gap therebetween. The machine has a frame defining a hollow interior with end cavities on axially opposite ends of the frame. A gas circulating system has an inlet that supplies high pressure gas to the frame interior and an outlet to collect gas passing therethrough. A liquid coolant circulating system has an inlet that supplies coolant to the frame interior and an outlet that collects coolant passing therethrough. The coolant inlet and gas inlet are generally located on the frame in a manner to allow coolant from the coolant inletmore » to flow with gas from the gas inlet to the gap. The coolant outlet and gas outlet are generally located on the frame in a manner to allow the coolant to be separated from the gas with the separated coolant and gas collected for circulation through their respective circulating systems.« less

Terahertz Imaging of Subjects With Concealed Weapons

DTIC Science & Technology

2006-05-01

pulsed imaging", Advanced Characterization, Therapeutics, and Systems XIV, Proceedings of SPIE, Vol. 5318: 23-33 6. Anthony E. Siegman , Lasers , p667...imagery. Both methods made use of in-house transceivers, consisting of two ultra-stable far-infrared lasers , terahertz heterodyne detection systems...SYSTEM The 1.56THz transceiver system at STL uses two carbon dioxide lasers paired individually with two far-infrared lasers . All four units are

High power laser downhole cutting tools and systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zediker, Mark S; Rinzler, Charles C; Faircloth, Brian O

Downhole cutting systems, devices and methods for utilizing 10 kW or more laser energy transmitted deep into the earth with the suppression of associated nonlinear phenomena. Systems and devices for the laser cutting operations within a borehole in the earth. These systems and devices can deliver high power laser energy down a deep borehole, while maintaining the high power to perform cutting operations in such boreholes deep within the earth.

Receiver Design, Performance Analysis, and Evaluation for Space-Borne Laser Altimeters and Space-to-Space Laser Ranging Systems

NASA Technical Reports Server (NTRS)

Davidson, Frederic M.; Sun, Xiaoli; Field, Christopher T.

1996-01-01

This progress report consists of two separate reports. The first one describes our work on the use of variable gain amplifiers to increase the receiver dynamic range of space borne laser altimeters such as NASA's Geoscience Laser Altimeter Systems (GLAS). The requirement of the receiver dynamic range was first calculated. A breadboard variable gain amplifier circuit was made and the performance was fully characterized. The circuit will also be tested in flight on board the Shuttle Laser Altimeter (SLA-02) next year. The second report describes our research on the master clock oscillator frequency calibration for space borne laser altimeter systems using global positioning system (GPS) receivers.

Differential correction system of laser beam directional dithering based on symmetrical beamsplitter

NASA Astrophysics Data System (ADS)

Hongwei, Yang; Wei, Tao; Xiaoqia, Yin; Hui, Zhao

2018-02-01

This paper proposes a differential correction system with a differential optical path and a symmetrical beamsplitter for correcting the directional dithering of the laser beams. This system can split a collimated laser beam into two laser beams with equal and opposite movements. Thus, the positional averages of the two split laser beams remain constant irrespective of the dithering angle. The symmetrical beamsplitter designed based on transfer matrix principle is to balance the optical paths and irradiances of the two laser beams. Experimental results show that the directional dithering is reduced to less than one-pixel value. Finally, two examples show that this system can be widely used in one-dimensional measurement.

A digital intensity stabilization system for HeNe laser

NASA Astrophysics Data System (ADS)

Wei, Zhimeng; Lu, Guangfeng; Yang, Kaiyong; Long, Xingwu; Huang, Yun

2012-02-01

A digital intensity stabilization system for HeNe laser is developed. Based on a switching power IC to design laser power supply and a general purpose microcontroller to realize digital PID control, the system constructs a closed loop to stabilize the laser intensity by regulating its discharge current. The laser tube is made of glass ceramics and its integrated structure is steady enough to eliminate intensity fluctuations at high frequency and attenuates all intensity fluctuations, and this makes it easy to tune the control loop. The control loop between discharge current and photodiode voltage eliminates the long-term drifts. The intensity stability of the HeNe laser with this system is 0.014% over 12 h.

Real-time laser cladding control with variable spot size

NASA Astrophysics Data System (ADS)

Arias, J. L.; Montealegre, M. A.; Vidal, F.; Rodríguez, J.; Mann, S.; Abels, P.; Motmans, F.

2014-03-01

Laser cladding processing has been used in different industries to improve the surface properties or to reconstruct damaged pieces. In order to cover areas considerably larger than the diameter of the laser beam, successive partially overlapping tracks are deposited. With no control over the process variables this conduces to an increase of the temperature, which could decrease mechanical properties of the laser cladded material. Commonly, the process is monitored and controlled by a PC using cameras, but this control suffers from a lack of speed caused by the image processing step. The aim of this work is to design and develop a FPGA-based laser cladding control system. This system is intended to modify the laser beam power according to the melt pool width, which is measured using a CMOS camera. All the control and monitoring tasks are carried out by a FPGA, taking advantage of its abundance of resources and speed of operation. The robustness of the image processing algorithm is assessed, as well as the control system performance. Laser power is decreased as substrate temperature increases, thus maintaining a constant clad width. This FPGA-based control system is integrated in an adaptive laser cladding system, which also includes an adaptive optical system that will control the laser focus distance on the fly. The whole system will constitute an efficient instrument for part repair with complex geometries and coating selective surfaces. This will be a significant step forward into the total industrial implementation of an automated industrial laser cladding process.

[The development of a distribution system for medical lasers and its clinical application].

PubMed

Okae, S; Ishiguchi, T; Ishigaki, T; Sakuma, S

1991-02-25

We developed a new laser beam generator system which can deliver laser beam to multiple terminals in distant clinical therapy rooms. The system possesses the distribution equipment by which Nd-YAG laser power is distributed to 8 output terminals under the computer control. Distributed laser beam is delivered to each distant terminal with clinical informations through the optical fiber. In the fundamental studies, possibility of distant transportation of laser beam (30 m) only with 10% loss of energy and without dangerous heating at the connection parts was shown. There seems to be no disadvantage associated with distribution laser beam. In the clinical study, the system was applied to five patients with the symptoms including hemosputum, esophageal stenosis, hemorrhage, lip ulcer and pain. Clinical usefulness of the system was proved. The advantages of the system are as follows: 1. Benefit of cost reduction due to multiple use of single laser source. 2. No necessity of transport of the equipment. 3. No requirement of a wide space to install the equipment in the distant room. 4. Efficient management and maintenance of the system by centralization. Further improvements, e.g., simultaneous use at multiple terminals and elongation of transportation up to 340 m, make the system more useful for clinical application.