Energy Technology Data Exchange (ETDEWEB)

A method for conditioning electron beams is proposed, making use of the TM{sub 210} mode of microwave cavities, to reduce the axial velocity spread within the beam, in order to enhance gain in resonant electron beam devices, such as the free-electron laser (FEL). Effectively, a conditioner removes the restriction on beam emittance. The conditioner is analyzed using a simple model for beam transport and ideal RF cavities. Analysis of an FEL is employed to evaluate performance with reduced axial velocity spread. Examples of FELs are presented showing the distinct advantage of conditioning.

Energy Technology Data Exchange (ETDEWEB)

The Air Force`s Armstrong Laboratory at Tyndall Air Force Base, Florida, has supported the research and development of Radio Frequency Soil Decontamination. Radio frequency soil decontamination is essentially a heat-assisted soil vapor extraction process. Site S-1 at Kelly Air Force Base, San Antonio, Texas, was selected for the demonstration of two patented techniques. The site is a former sump that collected spills and surface run-off from a waste petroleum, oils, and lubricants and solvent storage and transfer area. In 1993, a technique developed by the IIT Research Institute using an array of electrodes placed in the soil was demonstrated. In 1994, a technique developed by KAI Technologies, Inc. using a single applicator placed in a vertical borehole was demonstrated. Approximately 120 tons of soil were heated during each demonstration to a temperature of about 150 degrees Celsius.

International Nuclear Information System (INIS)

The dielectrical properties of organosilicon sealants have been studied in the wide range of temperatures in the low and radio frequencies range. The effect of thermal treatment and #gamma#-irradiation on these properties is discussed.

International Nuclear Information System (INIS)

Radio-frequency catheter ablation (RFCA) of the distal pulmonary veins is increasingly being used to treat recurrent or refractory atrial fibrillation that doesn't respond to pharmacologic therapy or cardioversion. Successful RFCA of atrial al fibrillation depends on the pre-procedural understanding of the complex anatomy of the distal pulmonary veins and the left atrium. Aim of this parer is to describe the technical main features that characterise the multidetector helical computed tomography in the evaluation of this anatomic region before and after RFCA procedure. The 3D post-processing techniques useful for pre-RFCA planning are straightforward.

Energy Technology Data Exchange (ETDEWEB)

Thin passive layers of uranium nitride were formed by nitriding pure metallic uranium in non-equilibrium, low pressure radio-frequency plasma of nitrogen. Plasma nitriding at low substrate temperature of 230 C-250 C was found to cause the formation of adherent layers of uranium sesquinitride ({alpha}-U{sub 2}N{sub 3}) which provide a considerable protection against hydrogen attack. The characteristics of these passivation layers were determined by X-ray diffraction and Auger electron spectroscopy. The incipient hydriding kinetics of the plasma-treated samples were compared with those of untreated and nitrogen-ion implantation ones, utilizing a hot-stage microscope that was monitored continuously with a TV camera and videotape. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The advantages of radiofrequency and microwaves, such as volumetric heating, rapid and selective heating, compactness of equipment and ease of operation, offer sound economic alternative heating techniques. This article discusses dielectric loss, its quantification, and how it is put to effective use, including the use of applicators. Brief recommendations are presented for whether to select radio frequency or microwaves for a particular application. Uses of radiofrequency and microwaves in the industrial, domestic and medical sectors are described.

Energy Technology Data Exchange (ETDEWEB)

The SciDAC2 accelerator project at SLAC aims to simulate an entire three-cryomodule radio frequency (RF) unit of the International Linear Collider (ILC) main Linac. Petascale computing resources supported by advances in Applied Mathematics (AM) and Computer Science (CS) and INCITE Program are essential to enable such very large-scale electromagnetic accelerator simulations required by the ILC Global Design Effort. This poster presents the recent advances and achievements in the areas of CS/AM through collaborations.

Energy Technology Data Exchange (ETDEWEB)

A new technique is described in this paper for a general active radio frequency (RF) filter trap that can be used for suppressing noise or interference on high voltage (HV) transmission lines. The technique exploits the Miller effect of an RF amplifier in conjunction with a special sensing circuit, and is potentially far more economical to implement than conventional techniques that use passive HV filter components.

International Nuclear Information System (INIS)

Radio frequency (RF) plasma nitriding using different input plasma processing powers (250-600 W) improves the surface of titanium by forming hard phases of TiN, Ti_2N, and Ti (N) into the surface. The characteristics of the compound layer have been investigated by optical microscopy, microhardness measurements, and X-ray diffraction. The effect of plasma power on the sample temperature, electron temperature, and plasma density was studied using Langmuir double probe. The measured surface hardness value of the compound layer is 2190 HV 0.1 for treated sample at plasma power 500 W. The compound thickness continuously increases as the plasma power increases. The highest nitriding rate of 5.88 #mu#m"2/s was recorded when the input plasma power was adjusted at 550 W. This high nitriding rate of treated titanium samples is ascribed to the high concentration of active nitrogen species in the plasma atmosphere and the formed microcracks near to the ...

International Nuclear Information System (INIS)

Nitrogen ion implantation improves the wear resistance of Ti-6Al-4V alloys by forming a hard TiN superficial passivation layer. However, the thickness of the layer formed by traditional ion implantation is typically 100-200 nm and may not be adequate for many industrial applications. We propose to use radio-frequency (RF) plasma nitriding and nitrogen plasma immersion ion implantation (PIII) to increase the layer thickness. By using a newly designed inductively coupled RF plasma source and applying a series of negative high voltage pulses to the Ti-6Al-4V samples. RF plasma nitriding and nitrogen PIII can be achieved. Our process yields a substantially thicker modified layer exhibiting more superior wear resistance characteristics, as demonstrated by data from micro-hardness testing, pin-on-disc wear testing, scanning electron microscopy (SEM), as well as Auger electron spectroscopy (AES). The performance of our newly developed inductively coupled RF plasma source ...

International Nuclear Information System (INIS)

Zinc oxide thin films were obtained by laser ablation of a Zn target in oxygen reactive atmosphere, the oxygen being supplied either by a standard gas inlet valve or from a radio-frequency (rf) oxygen plasma. Pt-coated silicon and MgO were used as substrates. The influence of the deposition parameters as laser wavelength (266, 355, 1064 nm), laser fluence (1.5-20 J/cm2) and oxygen pressure (1-60 Pa) was studied. The influence of the rf plasma beam addition on the morphological proprieties of zinc oxide films was particularly investigated, simultaneously with several configurations of the direction of the ablation plasma, the rf plasma beam and the substrate. The obtained films, with thicknesses in the range of 50 nm to 1 ?m have been characterized by atomic force microscopy (AFM), X-ray diffraction (XRD), transmission electron microscopy (TEM).

International Nuclear Information System (INIS)

In this work, the silicon oxynitride layer was studied as a tunneling layer for non-volatile memory application by fabricating low temperature polysilicon thin film transistors on glass. Silicon wafers were oxynitrided by only nitrous oxide plasma under different radio frequency powers and plasma treatment times. Plasma oxynitridation was performed in RF plasma using inductively coupled plasma chemical vapor deposition. The X-ray energy dispersive spectroscopy was employed to analyze the atomic concentration ratio of nitrogen/oxygen in oxynitride layer. The oxynitrided layer formed under radio frequency power of 150 W and substrate temperature of 623 K was found to contain the atomic concentration ratio of nitrogen/oxygen as high as 1.57. The advantage of high nitrogen concentration in silicon oxide layer formed by using nitrous oxide plasma was investigated by capacitance-voltage measurement. The ...

Energy Technology Data Exchange (ETDEWEB)

A billet of low-density carbon-bonded carbon fiber (CBCF) composite is machined into a desired attenuator or load element shape (usually tapering). The CBCF composite is used as a free-standing load element or, preferably, brazed to the copper, brass or aluminum components of coaxial transmission lines or microwave waveguides. A novel braze method was developed for the brazing step. The resulting attenuator and/or load devices are robust, relatively inexpensive, more easily fabricated, and have improved performance over conventional graded-coating loads.

International Nuclear Information System (INIS)

Magnetic materials such as yttrium iron garnet (YIG) are of great importance for its magneto-optic properties and for their potential applications in the domain of optical telecommunications. The deposition of thin films of YIG, on quartz or GGG (gadolinium gallium garnet) substrate, was performed using radio frequency non reactive magnetron sputtering, followed by high temperature annealing which is needed to enhance the crystallinity of the layers. Rutherford backscattering spectrometry RBS was used to determine the thickness and stoichiometry of the performed layers in order to investigate correlations between growth conditions and the quality of the final material. RBS measurements showed the influence of the deposition time and the temperature substrate on the film growth and its stoichiometry. (author)

British Library Electronic Table of Contents (United Kingdom)

Doped ultrafine silicon dioxide powder with a narrow particle size distribution was obtained by RF discharge-stimulated dichlorosilane (SiH2C) oxidation at a low pressure using isobutylene as the combustion inhibitor and chromium hexacarbonyl (Cr(CO)6) as the dopant. The formation and morphology of the ultrafine particles are governed by the parameters of the RF discharge and by the chemical mechanism of the combustion reaction yielding the aerosol. Submicron-sized filamentous carbon structures can be obtained by isobutylene decomposition under spark discharge conditions in the presence of a molybdenum metal catalyst.

British Library Electronic Table of Contents (United Kingdom)

A method to achieve NMR of dilute samples in the earth's magnetic field by applying para-hydrogen induced polarization is presented. Maximum achievable polarization enhancements were calculated by numerically simulating the experiment and compared to the experimental results and to the thermal equilibrium in the earth's magnetic field. Simultaneous 19F and 1H NMR detection on a sub-milliliter sample of a fluorinated alkyne at millimolar concentration (1018 nuclear spins) was realized with just one single scan. A highly resolved spectrum with a signal/noise ratio higher than 50:1 was obtained without using an auxiliary magnet or any form of radio frequency shielding.

Energy Technology Data Exchange (ETDEWEB)

The requirements for transporting high-current, negative-ion beams are presented with particular emphasis on applications involving negative-hydrogen-ion beams. In addition to the usual matching and steering problems, particular attention must be paid to beam emittance growth in the transport system. Depending on the application, a number of approaches have been developed using both magnetic and electric lenses. I discuss the design considerations for transporting and matching these beams to radio-frequency quadrupole accelerators, and present a survey of the various types of beamlines now used for negative-ion beams.

DEFF Research Database (Denmark)

OBJECTIVE: To evaluate the association between fatty acid (alpha-linolenic acid (ALA), EPA, DHA, palmitic, stearic, oleic, linoleic and arachidonic acids) intake and prospective weight change in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition. DESIGN: Prospective cohort study with mean follow-up time of 6.5 years. In a total of 9182 men and 10867 women aged 35 to 64 years, from body weight measurement at recruitment and calibrated body weight during follow-up, weight change was expressed as mean annual weight change relative to baseline weight (%/year) and categorised into four groups (weight loss, or =2.5 to or =7.5%/5 years). Energy-adjusted dietary fatty acid intake data were estimated from the FFQ completed at baseline. Multivariate linear regression models as well as multinomial logistic regression analyses (carbohydrate replacement models) were conducted. RESULTS: Stearic acid intake was linearly associated with ...

Energy Technology Data Exchange (ETDEWEB)

The use of capacitance sensors for measuring phase concentrations in two-phase flow has gained popularity in recent years. In designing such sensors, there are many issues which must be considered in order to optimize performance: two-phase flow regime, permittivity of the phases, duct geometry, electrical shielding, desired spacial resolution of film thickness, and temperature variation in the flow field. These design issues are discussed and are used to optimize the design of a capacitance sensor which is used to measure vapor volume fraction in annular, two-phase vertical upflow and downflow in a square duct. The sensor was tested and implemented in a 12.7 mm square duct mounted in a flow boiling facility containing FC-72, a low permittivity dielectric fluid ({epsilon}{sub r} = 1.75). Using analytical modeling, an adjustable-length, parallel-plate design was developed and refined to achieve good sensitivity to flow conditions. The sensor output was ...

Energy Technology Data Exchange (ETDEWEB)

Increase in power utility loads in industrialized countries, as well as developing countries, demands a higher level of transmission line voltage. Radio interference (RI) problems have been determined to be a limiting factor in selecting the size of transmission line conductors. Transmission line noise is primarily caused by corona discharges in the immediate vicinity of the conductor. It has been observed that discharges occur during both half-cycles of the applied voltage, but positive corona is usually predominant at AM radio frequencies range with practical high-voltage and extra high-voltage transmission lines. The corona radio noise effect is highly dependent upon the presence of particles on the surface of the conductor and the increase of the electrical gradient beyond the breakdown value of the air. Therefore, corona radio noise varies significantly with the weather and atmospheric conditions and generally increases by 10 to 30 dB in ...

British Library Electronic Table of Contents (United Kingdom)

In this study structural and magnetic character of the expanded austenite phase (gN) layer formed on a medical grade CoCrMo alloy by a low-pressure Radio-Frequency plasma nitriding process was investigated. The formation of the expanded austenite phase is facilitated at a substrate temperature near 400^oC for 1, 2, 4, 6 and 20h under a gas mixture of 60% N2-40% H2. The magnetic state of the gN layers was determined by a surface sensitive technique, magneto-optic Kerr effect (MOKE), and with a scanning probe microscope in magnetic force mode (MFM). Strong evidence for the ferromagnetic nature of the gN-(Co,Cr,Mo) phase is provided by the observation of stripe domain structures and the hysteresis loops. The ferromagnetic state for the gN phase observed here is mainly linked to large lattice ...

Energy Technology Data Exchange (ETDEWEB)

An apparatus for non-invasively inspecting an object, such as an item of luggage, for explosives material is described. It comprises a multi-channel thermal neutron inspection system having a plurality of neutron irradiation chambers. Simultaneous operation of several channels increases the maximum system throughput several times. Each chamber has a lithium neutron source which is stimulated to neutron production by a proton beam. Beam switching magnets are energised by pulsing to divert a common proton beam to each source in turn. The initial beam is generated by a radio frequency quadrupole accelerator. The advantages of this system are very low residual source activity and controllable neutron production thereby minimising safety hazards. The irradiation chamber may contain several different gamma ray detectors to identify the elements present in explosives material. In addition, a neutron radiography imaging means may be employed to ...

International Nuclear Information System (INIS)

A 20-MeV proton accelerator is developed by Proton Engineering Frontier Project (PEFP) at Korea Atomic Energy Research Institute (KAERI). The 20MeV accelerator consists of 50keV proton injector, 3MeV RFQ (Radio frequency Quadrupole), 20MeV DTL (Drift Tube Linac) and 20MeV beam line. The beam profile was measured at the end of the 20MeV beam line with wire scanner. Moreover the beam emittance was calculated from the quad scan method using beam line quadrupole magnets. In this paper, the beam profile measurement results are presented and the emittance measurement from the quad scan method is discussed

International Nuclear Information System (INIS)

Austenitic stainless steel AISI 304 has been nitrided by radio frequency (rf) plasma containing various nitrogen-hydrogen gas mixtures, in order to study the effect of hydrogen on structure and magnetic properties of the formed compound layer. The thermal temperature has been measured at the vicinity of the samples. The compound layer thus produced has been characterized using, X-ray diffractometer and vibration sample magnetometer. Providing the total pressure of nitrogen and hydrogen is held constant, the addition of hydrogen up to 50% gives new structural phases. The magnetization values of the plasma treated samples are strongly dependent on the percentage of H_2 in the gas phase. An excessive amount of hydrogen (#approx#75%) on the other hand, retards the nitriding process. The surface temperature of the sample and plasma condition is crucial factors for nitriding process.

Energy Technology Data Exchange (ETDEWEB)

Silicon thin film with thickness in range 1000-5300 A deposited on rough Cu foil by a radio frequency magnetron sputtering is used as anode materials for Li-ion rechargeable batteries. The SEM, XRD and TEM analysis reveals that the Si thin film has a floccular nano-sized multi-crystalline structure. Li ions insertion/extraction evaluation is performed mainly with constant current charge/discharge cycling and cyclic voltammetry (CV) at room temperature. The cycleability and reversible discharge capacity are found to depend on the film thickness, and thinner films give larger accommodation capacity. A 3120 A Si film provides a reversible specific capacity over 3500 mA hg{sup -1} with excellent cycleability under 0.5 C charge/discharge rate.

Science.gov (United States)

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International Nuclear Information System (INIS)

Exposure control at the operating Nuclear Power Station is a major concern. The challenging task of meeting the International standards in the field of radiation protection is the calibration of the radiation monitoring instruments and interpretation of personnel and area monitoring results. Correct interpretation is based on accurate calibration of radiation measuring instruments. The reliability and accuracy of the measurements are also partly based on the procedures applied in calibration. Inadequate calibration can cause large errors in dose estimation in complete dose rate range and energy range. Semiautomatic calibration facility established at TAPS 3 and 4 for radiation monitoring instruments. Objective of calibration facility is (a) Ensure instruments are working properly (b) calibration adjustment and (c) in case without ...

Energy Technology Data Exchange (ETDEWEB)

To assess the feasibility of transluminal radiofrequency thermal ablation using a stent-type electrode and to determine, by means of in-vivo and in-vivo animal studies, the appropriate parameters. In-vivo: the radiofrequency electrode used was a self-expandable nitinol stent with 1cm insulated ends. A stent was placed in the portal vein of bovine liver, and ablations at target temperatures of 70, 80, 90, and 100 .deg. C were performed. Ablated sizes were measured longitudinally. In vivo: four mongrel dogs were anesthetized, and a stent was inserted in the common bile duct under fluoroscopic guidance through an ultrasound-guided gall bladder puncture site. The ablation temperature was set at 80 .deg. C, and each dog underwent proximal and distal esophageal ablations lasting 12 minutes. They were sacrificed immediately. In-vivo: ablated sizes showed significant correlation with target temperatures (r>0.04; p<0.05). Although most lesions were fusiform, dumbbell-shaped ...

International Nuclear Information System (INIS)

A method has been developed for calibration of CT-numbers to volumetric electron density distributions using tissue substitutes of known elemental composition and experimentally determined electron density. This information have been used in a dose calculation method based on photon and electron interaction processes. The method utilizes a convolution integral between the photon fluence matrix and dose distribution kernels. Inhomogeneous media are accounted for using the theorems of Fano and O'Connor for scaling dose distribution kernels in proportion to electron density. For clinical application of a calculated dose plan, a method for prediction of accelerator output have been developed. The methods gives the number of monitor units that has to be given to obtain a certain absorbed dose to a point inside an irregular, inhomogeneous object. The method for verification of dose distributions outlined in this study makes it possible to exclude the treatment related ...

UK PubMed Central (United Kingdom)

BackgroundThe precision in carbon ion radiotherapy depends on the calibration of Hounsfield units (HU) as measured with computed tomography (CT) to water equivalence. This calibration...Full Text Available

Science.gov (United States)

We investigate the features of the spontaneous emission spectra in a coherently driven cold five-level atomic system by means of a radio frequency (rf) or microwave field driving a hyperfine transition within the ground state. It is shown that a few interesting phenomena such as spectral-line narrowing, spectral-line enhancement, spectral-line suppression, and spontaneous emission quenching can be realized by modulating the frequency and intensity of the rf-driving field in our system. In the dressed-state picture of the coupling and rf-driving fields, we find that this coherently driven atomic system has three close-lying levels so that multiple spontaneously generated coherence (SGC) arises. Our considered atomic model can be found in real atoms, such as rubidium or sodium, so a corresponding experiment can be done to observe the expected phenomena related to SGC reported by Fountoulakis et al. [Phys. Rev. A 73, 033811 (2006)], since no ...

Energy Technology Data Exchange (ETDEWEB)

ITN Energy Systems is developing next-generation solar cells based on the concepts of an optical rectenna. ITN's optical rectenna consists of two key elements: (1) an optical antenna to efficiently absorb the incident solar radiation, and (2) a high-frequency metal-insulator-metal (MIM) tunneling diode that rectifies the AC field across the antenna, providing DC power to an external load. The combination of a rectifying diode at the feedpoints of a receiving antenna is often referred to as a rectenna. Rectennas were originally proposed in the 1960s for power transmission by radio waves for remote powering of aircraft for surveillance or communications platforms. Conversion efficiencies greater than 85% have been demonstrated at radio frequencies (efficiency defined as DC power generated divided by RF power incident on the device). Later, concepts were proposed to extend the rectennas into the IR and optical region of the ...

International Nuclear Information System (INIS)

A novel technique is proposed for the growth of an InN film on a GaN/Al2O3(0001) template by radio-frequency plasma-excited molecular beam epitaxy (RF-MBE). The method involves 1) InN growth under an In-rich condition and 2) additional nitrogen radical irradiation after the InN growth under an In-rich condition. Excess In that appeared on the InN surface in the InN growth under an In-rich condition is transformed to InN by the additional nitrogen radical irradiation. The effective V/III ratio is easily controlled by monitoring the intensity in a reflection high-energy electron diffraction (RHEED) pattern. The growth of the InN film by repeating the InN growth under an In-rich condition and the additional nitrogen radical irradiation is also demonstrated. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

International Nuclear Information System (INIS)

A single plasma process involving three consecutive steps has been developed for producing high gas flow catalytic nanostructures on the electrodes of proton exchange membrane (PEM) fuel cells (FC). Using a high density helicon radio frequency (13.56 MHz) plasma, nickel is sputtered onto a porous carbon support. Changing the background gas from argon to methane/hydrogen allowed 2 ?m long, 37 nm diameter carbon nanofibres (CNFs) to be grown by diffusion through the nickel clusters in a 'tip growth' mechanism at the relatively low temperature of 400 deg. C. The third step involves plasma sputtering of platinum onto the CNFs, resulting in nanoclusters (3-8 nm) being formed on the periphery of the CNFs. Four FC cathodes were synthesized on carbon paper and PTFE/carbon loaded cloth (known as gas diffusion layer, GDL), both with and without CNFs, with the Pt/CNFs nanostructures grown on PTFE/carbon loaded cloth having the best FC performances. ...

International Nuclear Information System (INIS)

In partnership with the US Navy, high-technology corporations, and research universities, Jefferson Lab is building a superconducting radio-frequency (SRF) accelerator-driven free-electron laser (FEL) and is outfitting an FEL user facility. This first fourth-generation light source - a 1 kW, 3 #mu#m infrared (IR) laser - is the first step in a program to develop high-average-power SRF-based IR and ultraviolet (UV) FELs for multiple manufacturing applications as well as for defense-related applied research and basic scientific research. This initial FEL will be driven by a 42 MeV, 5 m A recirculating SRF linac similar to the much larger SRF linac in Jefferson Lab's 4 GeV, 200 #mu#A Continuous Electron Beam Accelerator Facility (CEBAF). The FEL is expected to demonstrate 75% energy recovery. Its linac will be cooled by the existing CEBAF cryogenic system. At Jefferson Lab, an infrastructure of facilities and people already supports the advance of SRF and closely ...

Energy Technology Data Exchange (ETDEWEB)

The temperature elevations in anatomically based human phantoms of an adult and a 3-year-old child were calculated for radio-frequency whole-body exposure. Thermoregulation in children, however, has not yet been clarified. In the present study, we developed a computational thermal model of a child that is reasonable for simulating body-core temperature elevation. Comparison of measured and simulated temperatures revealed thermoregulation in children to be similar to that of adults. Based on this finding, we calculated the body-core temperature elevation in a 3-year-old child and an adult for plane-wave exposure at the basic restriction in the international guidelines. The body-core temperature elevation in the 3-year-old child phantom was 0.03 deg. C at a whole-body-averaged specific absorption rate of 0.08 W kg{sup -1}, which was 35% smaller than in the adult female. This difference is attributed to the child's higher body surface area-to-mass ratio.

International Nuclear Information System (INIS)

This article describes the nature of the electromagnetic waves, what they are and how do they affect us. Current concern is focused on exposure to low level power-frequency magnetic fields like microwave radiation from mobile phones and leaking microwave ovens; high power radiation from defence and airport radars; fields close to high voltage transmission lines; radio frequency fields from industrial welders and heaters and DC magnetic fields in aluminium smelters. These fields with frequency less than 300 GHz do not carry sufficient energy to break chemical bonds and it is assumed that they cannot damage cell DNA. The amount of radiation absorbed by a human exposed to far field electromagnetic radiation (EMR) depends on the orientation and size of the person. In the 30-300 MHz range it is possible to excite resonance in the whole or partial body such as the head. It is emphasised that since there are some evidence that electromagnetic fields ...

International Nuclear Information System (INIS)

The macrotemporal structure of the Super-ACO Storage ring free-electron laser (FEL) can be either continuous, pulsed, or chaotic, and can present some rapid fluctuations. The temporal evolution of a storage ring FEL involves both the longitudinal motion of the positron beam (especially the synchrotron oscillations) and the FEL dynamics, as in a coupled system. Studies on the dynamics of the positron beam are performed here, in the goal to have a stable source for FEL applications, and to determine the conditions for a stable Q-switching experiment. The employed method is to study the influence of a controlled change of the radio frequency (RF) (modulation or frequency jump) on the beam. A simple theoretical model taking into account the perturbed RF system is presented to help the understanding of the experimental data. The different methods of measurement are described. Then, the results are given for several experimental conditions and the ...

Science.gov (United States)

The optically stimulated luminescent (OSL) radiation dosimeter technically surveys a wide dynamic measurement range and a high sensitivity. Optical fiber dosimeters provide capability for remote monitoring of the radiation in the locations which are difficult-to-access and hazardous. In addition, optical fiber dosimeters are immune to electrical and radio-frequency interference. In this paper, a novel remote optical fiber radiation dosimeter is described. The optical fiber dosimeter takes advantage of the charge trapping materials CaS:Ce, Sm that exhibit OSL. The measuring range of the dosimeter is from 0.1 to 100 Gy. The equipment is relatively simple and small in size, and has low power consumption. This device is suitable for measuring the space radiation dose and also can be used in high radiation dose condition and other dangerous radiation occasions. Supported by National Natural Science Foundation of China (10475112), Western Light Foundation of Chinese ...

International Nuclear Information System (INIS)

... actinides americium 241 americium 242 americium 243 calibration standards

Science.gov (United States)

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Energy Technology Data Exchange (ETDEWEB)

Turret moored Floating Production Storage and Offloading (FPSO) systems are considered suitable for a wide range of environmental conditions but experience of designing moorings for these units in harsh environments is limited. Furthermore, each floating production system has its own requirements as to the way the riser system is operated because of its dependence on both reservoir and site specific conditions. The current mooring codes do not have a consistent set of requirements; for example, the intact mooring system safety factors range from 1.5 to 2.3. Such vastly differing requirements result in wide variability in the intrinsic safety, reliability and cost. This paper describes a reliability analysis carried out for the first North Atlantic FPSO (Foinaven), to address the acceptance criteria for moorings by returning to the fundamentals. Although the analysis deals with FPSO`s, the approach is applicable to any catenary moored unit. One primary purpose of the mooring system is ...

International Nuclear Information System (INIS)

A Smith-Purcell oscillator with a thick electron beam is analyzed in its exponential gain regime. A threshold current less than 1[A] is found for a 1 mm wavelength; this threshold is much lower than that of a similar oscillator operating in a linear gain regime.

CERN Document Server

The amdlib AMBER data reduction software is meant to produce AMBER data products from the raw data files that are sent to the PIs of different proposals or that can be found in the ESO data archive. The way defined by ESO to calibrate the data is to calibrate one science data file with a calibration one, observed as close in time as possible. Therefore, this scheme does not take into account instrumental drifts, atmospheric variations or visibility-loss corrections, in the current AMBER data processing software, amdlib. In this article, we present our approach to complement this default calibration scheme, to perform the final steps of data reduction, and to produce fully calibrated AMBER data products. These additional steps include: an overnight view of the data structure and data quality, the production of night transfer functions from the calibration stars ...

UK PubMed Central (United Kingdom)

Modifications of the design and calibration procedure of a diffusion porometer permit determinations of stomatal resistance which agree well with results obtained by leaf energy balance. The energy...Full Text Available

International Nuclear Information System (INIS)

... PHYSICAL AND ANALYTICAL CHEMISTRY calibration standards diagrams

CERN Document Server

In this paper we describe the reconstruction strategies, the calibration procedures and the detector performance results from the latest CMS operation.

Energy Technology Data Exchange (ETDEWEB)

Ultra High Vacuum (UHV) test setup for electron gun testing has been developed. The development of next generation light sources and accelerators require development of klystron as a radio frequency power source, and in turn electron gun. This UHV electron gun test setup can be used to test the electron guns ranging from high average current, quasi-continuous wave to high peak current, single pulse etc. An electron gun has been designed, fabricated, assembled and tested for insulation up to 80 kV under the programme to develop high power klystron for future accelerators. Further testing includes the electron emission parameters characterization of the cathode, as it determines the development of a reliable and efficient electron gun with high electron emission current and high life time as well. This needs a clean ultra high vacuum to study these parameters particularly at high emission current. The cathode emission current, work function and ...

Energy Technology Data Exchange (ETDEWEB)

Ketamine-anesthetized Sprague-Dawley rats were exposed in H orientation to far-field 9.3-GHz continuous-wave (CW) and pulsed (2 microseconds 500 pps) radiofrequency radiation (RFR) at average power densities of 30 and 60 mW/sq. cm (whole-body average specific absorption rates of 9.3 and 18.6 W/kg, respectively). Irradiation was conducted to cyclicly increase colonic temperature from 38.5 to 39.5 C. Colonic, tympanic, and subcutaneous temperatures, ECG, blood pressure, and respiratory rate were continuously recorded during experimentation. At both power densities, the subcutaneous and tympanic temperature increases significantly exceeded the colonic temperature increase. At both exposure levels, heart rate increased significantly during irradiation and returned to baseline when exposure was discontinued. Blood pressure and respiratory rate did not significantly change during irradiation. There were no significant differences between the effects of CW and pulsed RFR exposure. The levels ...

International Nuclear Information System (INIS)

Fluorinated amorphous carbon (a-C:F) films were deposited by radio frequency bias assisted microwave plasma electron cyclotron resonance chemical vapor deposition with tetrafluoromethane (CF_4) and acetylene (C_2H_2) as precursors. The deposition process was performed at two flow ratios R=0.90 and R=0.97, where R=CF_4/(CF_4+C_2H_2). The samples were annealed at 300 deg. C for 30 min. in a N_2 atmosphere. Both Fourier transform infrared and electron spectroscopy for chemical analyzer were used to characterize the a-C:F film chemical bond and fluorine concentration, respectively. A high resolution electron energy loss spectrometer was applied to detect the electronic structure. The higher CF_4 flow ratio (R=0.97) produced more sp"3 linear structure, and it made the a-C:F film smoother and softer. A lifetime of around 0.34 #mu#s and an energy gap of #approx#2.75 eV were observed in both the as-deposited and after annealing conditions. The short ...

International Nuclear Information System (INIS)

Radio frequency (RF) sheaths are suspected of limiting the performance of present-day ion cyclotron range of frequencies (ICRFs) antennas over long pulses and should be minimized in future fusion devices. Within the simplest models, RF-sheath effects are quantified by the integral VRF = ? E|| ? dl where the parallel RF field E|| is linked with the slow wave. On 'long open field lines' with large toroidal extension on both sides of the antenna it was shown that VRF is excited by parallel RF currents j|| flowing on the antenna structure. In this paper, the validity of this simple sheath theory is tested experimentally on the Tore Supra (TS) ITER-like antenna prototype (ILP), together with antenna simulation and post-processing codes developed to compute VRF. The predicted poloidal localization of high-|VRF| zones is confronted to that inferred from experimental data analysis. Surface temperature distribution on ILP front face, as well as ...

International Nuclear Information System (INIS)

The operation and proper handling of equipment for measuring EMR-300 electromagnetic waves are studied and apply that knowledge to determine which areas of the metropolitan area are mostly affected by exposure to the emission of radiation. This team is able to measure magnetic field strength, electric field strength and power density, also can measure the most important parameters in a simple manner. International standards provide maximum values for these parameters that limit human exposure to such radiation. These standards are based on epidemiological several and laboratory that have been carried out in order to determine in which circumstances a biological entity is exposed to a level of radiation that can cause harm to their health. It focuses on measuring the level of radiation in certain areas of interest, which were chosen because are areas with high population density and also in proximity to antennas that emit electromagnetic waves. Before carrying out the data collection ...

Energy Technology Data Exchange (ETDEWEB)

The research for the development of flexible organic electronic devices (FEDs) is rapidly increasing worldwide, since FEDs will change radically several aspects of everyday life. Although there has been considerable progress in the area of flexible inorganic devices (a-Si or solution processed Si), there are numerous advances in the organic (semiconducting, conducting and insulating), inorganic and hybrid (organic-inorganic) materials that exhibit customized properties and stability, and in the synthesis and preparation methods, which are characterized by a significant amount of multidisciplinary efforts. Furthermore, the development and encapsulation of organic electronic devices onto flexible polymeric substrates by large-scale and low-cost roll-to-roll production processes will allow their market implementation in numerous application areas, including displays, lighting, photovoltaics, radio-frequency identification circuitry and chemical sensors, as well as to ...

Energy Technology Data Exchange (ETDEWEB)

Copper coatings deposited on Al-6061 substrates by radio frequency magnetron sputtering, to prevent the retention and permeation of energetically implanted tritium in Al-6061, were evaluated by a variety of characterization techniques. The coatings, weighing in the 0.03 to 0.088 kg/m{sup 2} range, were smooth and had a fine grain structure. They contained the intermetallic phases Cu{sub 9}Al{sub 4} and CuAl{sub 2} as well as copper. The fractions of Al and Cu in any coating increased and decreased, respectively, with increasing depth below the surface. Furthermore, the fractions of Al and Cu on the coating surface decreased and increased, respectively, with increasing coating weight. There was no texture or preferred orientation in the Cu phase of the coatings. A significant amount of oxygen was also detected at the original substrate surface. Residual stress measurements revealed that, in both Cu and CuAl{sub 2}, the stresses in the coating ...

Energy Technology Data Exchange (ETDEWEB)

Three electronic personal dosimeters (EPD-N) manufactured by Siemens, serial numbers 0635, 0658, and 0683, were tested at the Radiation Calibration Laboratory for an evaluation of their response to neutron, gamma and x-ray radiation. Designed to provide real-time neutron and photon dosimetry, the EPD-N is capable of estimating and displaying neutron and gamma dose components separately for a range of energies from 50 keV to 7 MeV for photon and 0.025 eV to > 10 MeV for neutron. All tests were conducted using the factory calibrations. A technical representative of the manufacturer indicated that site-specific calibrations are required as factory settings are calibrated for the lowest neutron energy limit of 0.025 eV. This raises concerns about the reliability of these devices in measuring neutrons when calibrations are made for a specific site radiological characterization ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes a signal simulator which is designed to calibrate eddy current probes. By using simultaneously an excitation coil and an electrically conducting plane, the simulator can emulate signals which correspond to spot welds with different flaws. The presence of a conducting plane allows a wide variation of the amplitude and phase of the excitation coil voltage during the calibration of a probe. A mathematical model for the simulator is derived and used to study the variation of the impedance change upon the parameters of the probe. Numerical computation shows that the impedance change depends in an important way on the frequency of the excitation coil current.

Energy Technology Data Exchange (ETDEWEB)

Calibration system for spot welding robots has been developed. The purpose of this system is to reduce the misalignment of tool center point (TCP) generated when teaching data made by off-line system is input to an actual robot. After the factor of the misalignment was analyzed, the relation between a main factor and the misalignment was modeled. In addition, the model was verified on experiment. The achievement of the accuracy requirement and practical use in the site was confirmed by the result of the verification. (author)

UK PubMed Central (United Kingdom)

OBJECTIVETo estimate the relationship between the rate of gestational weight gain before the 50-g, 1-hour oral glucose challenge test screening for gestational diabetes...Full Text Available

Science.gov (United States)

... changes in the wing shock/ separation patterns throughout ... to Reynolds number and tunnel flow quality before ... AGARD Conference Proceedings No ...

Science.gov (United States)

... in Taylor and Williamson.* Most satellite sensors cannot be ... The coordinates of the rocket Ii ... I - Incoming Global Radiant Flux between 0.285 and ...

Science.gov (United States)

Group deal delay solution has fit 42 psec with 2.4% outliers. Group delay ambiguities with spacing 3.9 ns (another world record!) were successfully resolved. ...

Science.gov (United States)

... Using a weighted linear regression on randomly selected coincident SSM/I-buoy pairs from each of the climate m codes, it was possible to produce ...

Energy Technology Data Exchange (ETDEWEB)

The Full Aperture Backscatter System (FABS) provides a measure of the spectral power, and integrated energy scattered by stimulated Brillouin (348-354 nm) and Raman (400 - 700 nm) scattering into the final focusing lens of the first four beams of the NIF laser. The system was designed to provide measurements at the highest expected fluences with: (1) spectral and temporal resolution, (2) beam aperture averaging, and (3) near-field imaging. This is accomplished with a strongly attenuating diffusive fiber coupler and streaked spectrometer and separate calibrated time integrated spectrometers, and imaging cameras. Measurement of the wavelength dependent sensitivity of the complete system is accomplished with a calibrated Xe lamp. Data from the calibration system is combined with experimental data to produce the power and energy measurements. Examples of measurements will be discussed.

Science.gov (United States)

replacing the KDP crystal, and introducing computer programs for accumulation of an almost unlimited number of frames. The calibration procedure using solar ...

British Library Electronic Table of Contents (United Kingdom)

Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS) has been proposed several years ago as an approach for quantitative analysis of Laser-Induced Breakdown Spectroscopy spectra. Recently developed refinement of the spectral processing method is described in the present work. Accurate quantitative results have been demonstrated for several metallic alloys. However, the degree of accuracy that can be achieved with Calibration-Free Laser-Induced Breakdown Spectroscopy analysis of generic samples still needs to be thoroughly investigated. The authors have undertaken a systematic study of errors and biasing factors affecting the calculation in the Calibration-Free Laser-Induced Breakdown Spectroscopy spectra processing. These factors may be classified in three main groups: 1) experi...

Energy Technology Data Exchange (ETDEWEB)

The effect of severe plastic deformation by cold high pressure torsion (HPT) on radio frequency (RF) plasma nitriding of pure iron, as well as St2K50 and X5CrNi1810 steels was investigated. Nitriding was carried out for 3 h in a nitrogen atmosphere at a pressure of 10{sup -5} bar and temperatures of 350 and 400 deg. C. Nitrided specimens were analysed by scanning electron microscopy (SEM), X-ray diffraction and micro hardness measurements. It was found that HPT enhances the effect of nitriding leading almost to doubling of the thickness of the nitrided layer for pure iron and the high alloyed steel. The largest increase in hardness was observed when HPT was combined with RF plasma nitriding at 350 deg. C. In the case of pure iron, the X-ray diffraction spectra showed the formation of {epsilon} and {gamma}' nitrides in the compound layer, with a preferential formation of {gamma}' at the expense of the {alpha}-phase at the ...

Energy Technology Data Exchange (ETDEWEB)

AC/DC voltage standards based entirely on solid-state references used as secondary, working, or transfer standards is widespread, although metrological performance is typically defined only via comparison with a higher level standard. The present report shows the improvements of the output metrological characteristics of an ac/dc calibrator by establishing three internal hierarchical levels of dc voltage references and by constant calibration of ac measuring circuits.

International Nuclear Information System (INIS)

Natural radioactive materials were used for detector calibration. We found that KCl is a very suitable material for this purpose. The efficiency curve shape was derived by using #gamma# ray lines of "2"1"4Bi normalised using a known quantity of KCl in the same geometry. The best fit was found by the least squares method. The summing correction coefficients for "2"1"4Bi are determined. (orig.).

Energy Technology Data Exchange (ETDEWEB)

A modulation transfer function (MTF) calibration method based on binary pseudo-random (BPR) gratings and arrays [Proc. SPIE 7077-7 (2007), Opt. Eng. 47, 073602 (2008)] has been proven to be an effective MTF calibration method for a number of interferometric microscopes and a scatterometer [Nucl. Instr. and Meth. A616, 172 (2010)]. Here we report on a further expansion of the application range of the method. We describe the MTF calibration of a 6 inch phase shifting Fizeau interferometer. Beyond providing a direct measurement of the interferometer's MTF, tests with a BPR array surface have revealed an asymmetry in the instrument's data processing algorithm that fundamentally limits its bandwidth. Moreover, the tests have illustrated the effects of the instrument's detrending and filtering procedures on power spectral density measurements. The details of the development of a BPR test sample suitable ...

Science.gov (United States)

The collection of papers in this issue of Mycologia documents considerable improvements in taxon sampling and phylogenetic resolution regarding the Fungal Tree of Life. The new data will stimulate new attempts to date divergences and correlate events in fungal evolution with those of other organisms. Here, we review the history of dating fungal divergences by nucleic acid variation and then use a dataset of 50 genes for 25 selected fungi, plants and animals to investigate divergence times in kingdom Fungi. In particular, we test the choice of fossil calibration points on dating divergences in fungi. At the scale of our analysis, substitution rates varied without showing significant within-lineage correlation, so we used the Langley-Fitch method in the R8S package of computer programs to estimate node ages. Different calibration points had a dramatic effect on estimated divergence dates. The estimate for the age of the Ascomycota/Basidiomycota ...

CERN Document Server

This thesis describes hadron reconstruction at the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) at CERN, Geneva. The focus is on the particle flow reconstruction of these objects. This thesis revisits the subject of the CMS calorimeters' non-linear response to hadrons. Data from testbeam experiments conducted in 2006 & 2007 is compared with simulations and substantial differences are found. A particle flow calibration to correct the energy response of the testbeam data is evaluated. The reconstructed jet response is found to change by ~ 5% when a data-driven calibration is used in place of the calibration derived from simulation. Collision data taken at the early stage of CMS' commissioning is also presented. The hadron response in data is determined to be compatible with testbeam results presented in this thesis. This thesis also details the use of neural networks to improve the energy ...

Energy Technology Data Exchange (ETDEWEB)

A novel method to control the mixed-mode bending (MMB) specimen is presented. By maintaining a constant opening, or Mode 1, displacement rate, stable delamination growth is achieved for all mixed-mode ratios. A constant-opening displacement rate is achieved by attaching a second displacement transducer to the hinges of the specimen. The test machine is then controlled externally by the second displacement transducer. By achieving stable delamination growth and monitoring the opening displacement, an experimental compliance calibration may be derived for the Modes 1 and 2 parts. This new approach to control the test and determine the experimental compliance calibration, overcomes the potential inaccuracies of the previously used beam theory expressions to determine compliance and to separate the modal values of G.

International Nuclear Information System (INIS)

Realization of the scale of spectral responsivity of the detectors in the Directorate of Measures and Precious Metals (DMDM) is based on silicon detectors traceable to LNE-INM. In order to realize the unit of spectral irradiance in the laboratory for photometry and radiometry of the Bureau of Measures and Precious Metals, the new method based on the calibration of the spectroradiometer by comparison with standard detector has been established. The development of the method included realization of the System of Spectral Comparisons (SSC), together with the detector spectral responsivity calibrations by means of a primary spectrophotometric system. The linearity testing and stray light analysis were preformed to characterize the spectroradiometer. Measurement of aperture diameter and calibration of transimpedance amplifier were part of the overall experiment. In this paper, the developed method is presented and measurement ...

International Nuclear Information System (INIS)

Solid state nuclear track detectors (SSNTD) are widely used for radon measurements and CR-39 is one of the most popular SSNTD. In this work it was determined the calibration factor for radon concentration measurements through the passive method with CR-39 detectors. The detectors were put in a proper device (an adapted Lucas cell) and exposed to the standard radon concentration through the Pylon Model RN-150 flow through radon gas source. After exposure, the detectors were etched for 5.5 hours in a KOH solution at 80 deg C in a bath at a constant temperature. The track density was read in an Axiolab-Zeiss optical microscope, with nominal magnification of X10 connected to a video camera and to a personal computer. The calibration factor was obtained through the relation between standard radon concentration, track density and exposure time. (author)

British Library Electronic Table of Contents (United Kingdom)

BACKGROUND: Calibration by inverse modelling was performed with the MACRO transport and fate model using long-term (>10 years) drainflow and isoproturon (IPU) data from western France. Two lack-of-fit (LOF) indices were used to control the inverse modelling: sum of squares (SS) and an alternative statistic called the vertical-horizontal distance integrator (VHDI), which is designed to account for offsets in observed and predicted arrival times of peak IPU concentration. With these data, SS was artificially inflated because it is limited to comparison of predicted and observed IPU concentrations that are concurrent in time. The LOFs were used along with the index of agreement (d) and the correlation coefficient (r) to ascertain the fit of the calibrated models. RESULTS: Predicted arrival ti...

Science.gov (United States)

... upland development or destroyed during sand and gravel pit mining operations. Gains Increases in nonvegetated wetlands mainly through pond ... ...

Science.gov (United States)

Based on a collisional-radiative model, an atomic-kinetic calculation of the gains on the 41.8-nm transitions of Pd-like xenon was performed for the plasma produced due to the interaction of a femtosecond laser pulse with gaseous xenon. The gains g(z,{tau}) averaged over the spatial and temporal coordinates were compared with the known gains which had been measured experimentally in Xe{sup 8+}. The amplification was shown to occur under the conditions of ionisation of the working ions, and the time of output radiation saturation depends on the time of Xe{sup 8+} transformation to higher-ionised ions. Our theoretical investigation enables determining the optimal pump parameters, at which the product of the gain g by the active medium length L is about 20, which exceeds the experimental gL value. (active media)

Energy Technology Data Exchange (ETDEWEB)

Previous analyses of binary cycles for conversion of geothermal energy from moderate temperature resources to electrical energy have shown potential gains in net geofluid effectiveness of on the order of 8%, resulting from selection of turbine-expansion processes whose equilibrium states pass through the two-phase region (assuming major condensation does not occur). If condensation occurs, this gain could be reduced or eliminated by the resulting loss in turbine efficiency. Experience with many fluids, however, indicates that vapor supersaturation (or subcooling) permits metastable pure-vapor states to exist at temperatures considerably below the saturation temperature at a given pressure; thus, by better understanding the condensation process, and properly structuring the cycle, substantial performance gains may be achievable. The present study assessed, qualitatively, the probability for attaining this performance ...

Science.gov (United States)

... Except for isolated radiation accidents over the ensuing years, little practical experience has been gained in the treatment of thermal injuries ...

Science.gov (United States)

We report the characteristics of visible vertical cavity surface emitting laser diodes. Wafers are grown such that the Fabry--Perot resonance wavelength changes with position from 690 to 620 nm, overlapping to varying degrees with the [ital n]=1 and [ital n]=2 quantum well gain peaks at [similar to]670 and 650 nm. Gain guided devices are tested across the entire wafer, and pulsed room temperature lasing is observed from 634.6 to 663.2 nm. Our results suggest that gain contributions from the second quantized state are required to overcome high cavity losses in order to achieve lasing.

Energy Technology Data Exchange (ETDEWEB)

The Fermilab Steering Group has developed a plan to keep U.S. accelerator-based particle physics on the pathway to discovery, both at the Terascale with the LHC and the ILC and in the domain of neutrinos and precision physics with a high-intensity accelerator. The plan puts discovering Terascale physics with the LHC and the ILC as Fermilab's highest priority. While supporting ILC development, the plan creates opportunities for exciting science at the intensity frontier. If the ILC remains near the Global Design Effort's technically driven timeline, Fermilab would continue neutrino science with the NOVA experiment, using the NuMI (Neutrinos at the Main Injector) proton plan, scheduled to begin operating in 2011. If ILC construction must wait somewhat longer, Fermilab's plan proposes SNuMI, an upgrade of NuMI to create a more powerful neutrino beam. If the ILC start is postponed significantly, a central feature of the proposed Fermilab plan calls for building ...

Science.gov (United States)

tial/angular spreading of incident photons from a point source caused by the instrument (de- .... Filter. CDTP0001= 'DATA. ' / Type of calibration. CCNM0001= '2D_PSF ' ... the final resolution of sigma=0.5 arcmin in all energy bands. ...

Science.gov (United States)

... 3.0 Radar Measurements 3-1 3. 1 Spectral Density Measurements 3-2 3. 1. 1 System Calibration 3-3 ... 3. 1 SPECTRAL DENSITY MEASUREMENTS ...

Wastenet

... Top of page Testing Radiation coming from granite countertops results from natural radioactive material in the granite. Identifying the presence and concentration of radioactive elements in granite requires expensive and sophisticated portable instruments or laboratory equipment. These instruments and equipment require proper calibration, and interpretation of ...

Energy Technology Data Exchange (ETDEWEB)

A custom-built graphite-coated transmission ionization chamber is compared to the VacuDAP 2001 (VacuTec, Dresden, Germany), which has transparent conductive electrodes. A study was made of the dependence of response on x-ray tube potential for both types of chamber under identical conditions of exposure using over-table and under-table x-ray tubes. Since the calibration factor is the dose-area product of the radiation incident on the patient per chamber reading, it depends on the intrinsic response of the chamber as well as the effect of material in the beam between the x-ray tube and patient. Differences of about 20% were measured between the intrinsic and the over-table calibration factors and between the over-table and the under-table calibration factors for both chambers. The VacuDAP display is specifically calibrated for the over-table condition and would overstate the actual DAP in the under-table ...

Science.gov (United States)

To calibrate channels A1 to A4 for particles with Z >= 1, tests were done on the IBIS accelerator at AERE, Harwell, which gave protons up to 3 MeV. ...

UK PubMed Central (United Kingdom)

We present a method to make phantoms of coronary arteries for intravascular optical coherence tomography (IV-OCT). The phantoms provide a calibrated OCT response similar to the layered structure of...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A detailed component-based simulation model of a geothermal heat pump system has been calibrated to monitored data taken from a family housing unit located at Fort Polk, Louisiana. The simulation model represents the housing unit, geothermal heat pump, ground heat exchanger, thermostat, blower, and ground-loop pump. Each of these component models was 'tuned' to better match the measured data from the site. These tuned models were then interconnect to form the system model. The system model was then exercised in order to demonatrate its capabilities.

CERN Document Server

PAMELA is a space telescope orbiting around the Earth since June 2006. The scientific objectives addressed by the mission are the measurement of the antiprotons and positrons spectra in cosmic rays, the hunt for anti-nuclei as well as the determination of light nuclei fluxes from Hydrogen to Oxygen in a wide energy range and with very high statistics. In this paper the charge discrimination capabilities of the PAMELA Time-Of-Flight system for light nuclei, determined during a beam test calibration, will be presented.

Energy Technology Data Exchange (ETDEWEB)

This thesis presents the work achieved to instrument the ATLAS software framework, ATHENA, with a library of tools and utensils for the physics analysis as well as the extraction of the jet energy scale using physics events (in-situ calibration). The software part presents the various components of the ATHENA framework which handles the simulated and reconstructed data flow as well as the different stages of this process, before and during the data taking. The building of a library of tools easing the reconstruction of physics objects, their association with Monte-Carlo particles and their API is then explained. The need for common language and collaboration-wide utensils is emphasised as it allows to share the workload of validating these tools and to get reproducible physics results. The analysis part deals with the implementation of a light jet energy scale calibration algorithm within the C++ framework. This calibration ...

Wastenet

...events Completing the Trust and Estate Tax Return Completing and filing the trust tax return - filing online, avoiding common mistakes, tax return deadlines and penalties Trusts and Income Tax How different types of trust income are taxed, what management expenses and reliefs can be deducted, understanding the tax pool Trusts and Capital Gains Tax Capital Gains Tax exemptions and reliefs for trustees and notifying HMRC about a trust disposal or ...

Energy Technology Data Exchange (ETDEWEB)

The polarization characteristics of spontaneous radiation from relativistic electrons moving through helical and planar wiggler fields are evaluated for imperfect beam injection. Maximum coherent gain in free-electron laser systems are seen to occur in optical fields having these polarization characteristics rather than those of the wiggler magnets. Coupling coefficients for an electron beam skewed at an angle to the optical mode are presented.

Energy Technology Data Exchange (ETDEWEB)

Previous analyses of binary cycles for conversion of geothermal energy from moderate temperature resources to electrical energy have shown potential gains in net geofluid effectiveness on the order of 8%, resulting from selection of turbine-expansion processes whose equilibrium states pass through the two-phase region. If condensation occurs, this gain could be reduced or eliminated by the resulting loss in turbine efficiency. Experience with many fluids, however, indicates that vapor supersaturation permits metastable pure-vapor states to exist at temperatures considerably below the saturation temperature at a given pressure; thus, by better understanding the condensation process, and properly structuring the cycle, substantial performance gains may be possible. The purpose of the present study was to assess the probability for attaining this performance gain by estimating the extent of condensation ...

Science.gov (United States)

On-orbit spectral calibration of hyperspectral imaging data is a key step for quantitatively analyzing them. Like the atmospheric correction, accurate spectral calibration is very necessary for improved studies of land or ocean surface properties. Based on the previous literatures, a new method which coupled an optimization algorithm was developed to simultaneously retrieve the central wavelength and the full width at half maximum (FWHM) of the hyperspectral sensor without needing the in situ reflectance spectra. Firstly, the Hyperion data set simulated using MODTRAN4 with the Hyperion spectral specification was used to test the new method, and the results indicated that the maximum error was less than 0.1 and 0.7 nm for central wavelength and FWHM respectively when the spectral shift is 5 nm. Then the algorithm was applied to the Hyperion data acquired on May 20, 2008 over Heihe River Basin and it was iteratively performed for each detector of ...

Energy Technology Data Exchange (ETDEWEB)

In large samples, the {gamma}-ray count rate of a prompt gamma neutron activation analysis system is a multi-variable function of the elemental dry composition, density, water content and thickness of the material. The experimental calibration curves require tremendous laboratory work, using a great number of standards with well-known compositions. Although a Monte Carlo simulation study does not avoid the experimental calibration work, it reduces the number of experimental calibration standards. This paper is part of a feasibility study for a PGNAA system for on-line continuous characterisation of cement raw material conveyed on a belt (Oliveira, C., Salgado, J. and Carvalho, F. G. (1997) Optimisation of PGNAA instrument design for cement raw materials using the MCNP code. J. Radioanal. Nucl. Chem. 216(2), 191-198; Oliveira, C., Salgado, J., Goncalves, I. F., Carvalho, F. G. and Leitao, F. (1997a) A Monte Carlo study of ...

International Nuclear Information System (INIS)

Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS) has been proposed several years ago as an approach for quantitative analysis of Laser-Induced Breakdown Spectroscopy spectra. Recently developed refinement of the spectral processing method is described in the present work. Accurate quantitative results have been demonstrated for several metallic alloys. However, the degree of accuracy that can be achieved with Calibration-Free Laser-Induced Breakdown Spectroscopy analysis of generic samples still needs to be thoroughly investigated. The authors have undertaken a systematic study of errors and biasing factors affecting the calculation in the Calibration-Free Laser-Induced Breakdown Spectroscopy spectra processing. These factors may be classified in three main groups: 1) experimental aberrations (intensity fluctuations and inaccuracy in the correction for spectral efficiency of a detection system), 2) inaccuracy ...

Energy Technology Data Exchange (ETDEWEB)

The light gain due to S/sub 2/ molecules in a supersonically cooled gas mixture is calculated. The S/sub 2/ molecules formed due to the recombination of the sulfur atoms, and the combustion gas mixture was preheated in a precombustion chamber. Optimal gas flow and nozzle parameters are found which correspond to the highest possible light gain using Cs/sub 2/-Ar and S/sub 2/-Ar gas mixtures. The steady state gas flow in the nozzle was calculated, taking into account the chemical reactions in the one-dimensional approximation. It is shown that the maximum gain values vary in the 0.0001-0.002 range for gas pressures in the precombustion chamber in the range 10-100 atm. The optimal initial relative concentration of Cs/sub 2/ molecules and S/sub 2/ molecules are given. 32 references.

International Nuclear Information System (INIS)

This Letter reports the first experimental results from the world's first distributed optical-klystron (DOK) free-electron laser (FEL), the DOK-1 FEL, at Duke University. The DOK-1 FEL is a hybrid system, comprised of four wigglers: two horizontal and two helical. With the DOK-1 FEL, we have obtained the highest FEL gain among all storage ring based FELs at 47.8% (#+-#2.7%) per pass. We have also demonstrated that the FEL gain can be enhanced by increasing electron bunching using wigglers with a different polarization. Furthermore, we have realized controlled polarization switches of the FEL beam by a nonoptical means through the manipulation of a buncher magnet.

Science.gov (United States)

Automatic weapons such as machine guns and submachine guns are found in the German-speaking region only in special army and police units and appear accordingly rarely in homicides, suicides and accidents. In the following, the findings in two cases of death with the use of machine and submachine guns are presented. The first case was a fatal accident during shooting on a training area (current machine gun of the German army, calibre 7.62 x 51 mm), the second case was a killing during a physical conflict (submachine gun MP 40 from World War II, calibre 9 x 19 mm). In the case with the machine gun autopsy disclosed typical entry holes corresponding to the calibre, but unusually large exit wounds with tissue bridges in the wound ground, measuring 4 x 2.5 cm in diameter. By contrast, the second case (submachine gun) showed "normal" entry and exit wounds. The differences are mainly caused by deviating ballistic data of the ...

CERN Document Server

ALICE (A Large Ion Collider Experiment) is the heavy-ion detector designed to study the physics of strongly interacting matter and the quark-gluon plasma at the CERN Large Hadron Collider (LHC). Some specific calibration tasks are performed regularly for each of the 18 ALICE sub-detectors in order to achieve most accurate physics measurements. These procedures involve events analysis in a wide range of experimental conditions, implicating various trigger types, data throughputs, electronics settings, and algorithms, both during short sub-detector standalone runs and long global physics runs. A framework was designed to collect statistics and compute some of the calibration parameters directly online, using resources of the Data Acquisition System (DAQ), and benefiting from its inherent parallel architecture to process events. This system has been used at the experimental area for one year, and includes more than 30 ...

Energy Technology Data Exchange (ETDEWEB)

Versatility of the TRNSYS software program, the ease with which new components can be incorporated into the software, and its application to simulate heat pump systems was discussed. A case history was described in which the package, augmented by the addition of several recent large-scale heat pump projects, was used in calibrating a residential geothermal heat pump system at a military housing project in Fort Polk, LA. The project involved retrofitting over 4000 air source heat pumps with geothermal heat pumps in an energy savings performance contract. The calibration of the component models led to a system model which accurately predicts the performance of the geothermal heat pump. The lessons learned from the calibration exercise were used to help to predict the energy savings from one of the electric feeders at the base which serves some 200 of the 4000+ apartments. Energy savings estimates within one per cent of the ...

Energy Technology Data Exchange (ETDEWEB)

The aim of this paper is offering a critical review of Calibration-Free Laser-Induced Breakdown Spectroscopy (CF-LIBS), the approach of multi-elemental quantitative analysis of LIBS spectra, based on the measurement of line intensities and plasma properties (plasma electron density and temperature) and on the assumption of a Boltzmann population of excited levels, which does not require the use of calibration curves or matrix-matched standards. The first part of this review focuses on the applications of the CF-LIBS method. Quantitative results reported in the literature, obtained in the analysis of various materials and in a wide range of experimental conditions, are summarized, with a special emphasis on the departure from nominal composition values. The second part is a discussion of the simplifying assumptions which lie at the basis of the CF-LIBS algorithm (stoichiometric ablation and complete atomization, thermal equilibrium, homogeneous ...

Science.gov (United States)

Composed of Sun sensors, the Canopus sensor, the inertial reference unit, ... The heart of the system was a 100-pound-thrust rocket whose hypergolic, ... The spacecraft's low-gain antenna picked up all incoming signals from the NASA-JPL ...

UK PubMed Central (United Kingdom)

Strategies to combine aspirated marrow cells with scaffolds to treat connective tissue defects are gaining increasing clinical attention and use. In situations such as large defects where initial...Full Text Available

Science.gov (United States)

The advanced technologies of Ka-Band systems such as high gain spot .... sometimes used based on link requirements for a specific application. .... received at NASA LeRC from a Ku-band satellite and retransmitted to the USAT at Ka-Band. .... and to the Office of Management and Budget, Paperwork Reduction Project ...

UK PubMed Central (United Kingdom)

If bone strength was the only requirement of skeleton, it could be achieved with bulk, but bone must also be light. During growth, bone modelling and remodelling optimize strength, by depositing bone...Full Text Available

UK PubMed Central (United Kingdom)

SUMMARYThe biologic and clinical significance of KIT overexpression that associates with KIT gain-of- function mutations occurring in subsets...Full Text Available

UK PubMed Central (United Kingdom)

Computer-aided diagnosis of neural diseases from EEG signals (or other physiological signals that can be treated as time series, e.g., MEG) is an emerging field that has gained much attention in past...Full Text Available

UK PubMed Central (United Kingdom)

Outpatient practice after percutaneous coronary intervention (PCI) is gaining momentum due to constantly optimizing results. Furthermore, the availability of limited beds to handle the large volume...Full Text Available

UK PubMed Central (United Kingdom)

To gain insight into the process of mitochondrial transmission in yeast, we directly labeled mitochondrial proteins and mitochondrial DNA (mtDNA) and observed their fate after the fusion of two cells....Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A comparitive analysis is made of the principal characteristics of narrow-band and conventional semiconductor light amplifiers. It is shown that quasi-distributed filtering of the spontaneous radiation ensures a high gain and a low level of the spontaneous noise at the amplifier output.

UK PubMed Central (United Kingdom)

To gain insight into ATP-binding cassette transporter A1 (ABCA1) function and its potential role in AD pathology, we analyzed the expression of the cholesterol transporter ABCA1...Full Text Available

UK PubMed Central (United Kingdom)

Most human diseases are related in some way to the loss or gain in gene functions. Regulation of gene expression is a complex process. In addition to genetic mechanisms, epigenetic causes are...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A fully quantized many-particle theory of the standard free-electron laser in the small-signal, cold-beam regime is presented. The approach is based on an evaluation of the time-evolution operator in the interaction picture to first order in the quantum-mechanical recoil. For algebraic convenience we use the moving (Bambini-Renieri) frame, in which resonance occurs for zero electron momentum. Though we neglect space-charge effects, genuine many-particle contributions still show up, because the radiation emitted by one electron can be amplified by another electron. Our main results are gross features of the amplification, such as gain and spread, are virtually without many-particle effects. These effects are mainly important in the case of spontaneous emission. For a sufficiently high current, the buildup of the laser field from vacuum is enhanced by amplified spontaneous emission. Incoherence of the spontaneous radiation from several electrons induces deviations ...

UK PubMed Central (United Kingdom)

Epicuticular wax production was evaluated along the length of expanding leek (Allium porrum L.) leaves to gain insight into the regulation of wax production. Leaf segments from the...Full Text Available

UK PubMed Central (United Kingdom)

The use of spatially referenced data in cancer studies is gaining in prominence, fueled by the development and availability of spatial analytic tools and the broadening recognition of the linkages between...Full Text Available

Science.gov (United States)

The frequency dependence of the lasing power of a He-Ne laser was studied using the electrooptic effect in a KDP crystal. The gain profile of the power curve was found to differ noticeably between the high-frequency and low-frequency edges. (AIP). (AIP)

UK PubMed Central (United Kingdom)

This article reports on a one-semester Advanced Cell Biology course that endeavors to bridge the gap between gaining basic textbook knowledge about cell biology and learning to think and work as a researcher....Full Text Available

UK PubMed Central (United Kingdom)

Dictyostelium discoideum (Dd) is a widely studied model system from which fundamental insights into cell movement, chemotaxis, aggregation and pattern formation can be gained. In this system aggregation...Full Text Available

International Nuclear Information System (INIS)

Reactor Power Measurement is an essential part of the Reactor Power Control Loop in PHWRs. None of the available power measuring sensor offers characteristics which allow their direct use in the Reactor Power Control Loop. Thermal power, which is considered as relatively accurate, suffers from measurement delays and is used only as reference. Neutronic power sensors like Ion Chambers and Self Powered Neutron Detectors (SPNDs) which sense instantaneous power suffer from inaccuracies. A technique is required which makes use of both types-reference power and instantaneous power to extract real power information from the signals. This paper describes techniques to calibrate (correct) neutronic power that with the thermal reference power signals. The paper also brings out limitation of the calibration technique. (author)

British Library Electronic Table of Contents (United Kingdom)

Some factors affecting the accuracy of magnitude calibration of palaeoearthquakes are discussed. The general problem is illustrated by two case studies. First, the 2003 strong earthquake in the Altai region (Russia-Mongolia border), which has generated co-seismic surface faulting is considered. An analysis is conducted to determine how accurately its magnitude could be defined after 2000 years based on surface faulting parameters, retrieved when future palaeoearthquake studies are launched. This example demonstrates that accurate evaluation of magnitude is possible if specific regional seismotectonic features are taken into account and surface faulting parameters are measured over a dense grid. Next, the Muya earthquake that occurred in the Baikal seismic region in 1957 is studied with res...

British Library Electronic Table of Contents (United Kingdom)

Abstract Mammalian teeth exhibit incremental structures representing successive forming fronts of enamel at varying time scales, including a short daily increment called a cross striation and a long period called a stria of Retzius, the latter of which, in humans, occurs on average every 8-9 days. The number of daily increments between striae is called the repeat interval, which is the same period as that required to form one increment of bone, i.e. the lamella, the fundamental - if not archetypal - unit of bone. Lamellae of known formation time nevertheless vary in width, and thus their measures provide time-calibrated growth rate variability. We measured growth rate variability for as many as 6 years of continuously forming primary incremental lamellar bone from midshaft femur histologic...

International Nuclear Information System (INIS)

Tank calibration experiments have been carried out using a mock-up input accountancy tank with the object of developing a high accuracy solution volume measurement technique for Rokkasho Reprocessing Plant (RRP). The experimental parameters such as temperature, solution density, off gas pressure and so on have been fluctuated in the calibration experiments in order to evaluate the influence on the solution volume measurement. As a result, it was confirmed that the solution volume measurement error of the mock-up tank was within #+-#0.04% (at full volume) using careful data correction technique for measured data. For the high accuracy volume measurement at RRP, it is important to correct data properly taking account of the actual conditions such as uncontrollable ambient temperature that are different from the experiment. (author)

Energy Technology Data Exchange (ETDEWEB)

The task of designing high performance X-ray optical systemsrequires the development of sophisticated X-ray scattering calculationsbased on rigorous information about the optics. One of the mostinsightful approaches to these calculations is based on the powerspectral density (PSD) distribution of the surface height. The majorproblem of measurement of a PSD distribution with an interferometricand/or atomic force microscope arises due to the unknown ModulationTransfer Function (MTF) of the instruments. The MTF characterizes theperturbation of the PSD distribution at higher spatial frequencies. Here,we describe a new method and dedicated test surfaces for calibration ofthe MTF of a microscope. The method is based on use of a speciallydesigned Binary Pseudo-random (BPR) grating. Comparison of atheoretically calculated PSD spectrum of a BPR grating with a spectrummeasured with the grating provides the desired calibration of theinstrumental MTF. The ...

Energy Technology Data Exchange (ETDEWEB)

The /sup 252/Cf-source-driven noise analysis method determines the subcriticality of a system containing fissionable material from the ratio of cross power spectral densities between the detectors that detect particles from the fission process and between these detectors and an ionization chamber containing a spontaneously fissioning neutron source which provides neutrons to induce fission in the system. This method has two advantages: (1) a calibration is not required and thus subcriticality can be determined from measurements only on the subcritical system of interest, and (2) the subcriticality is independent of the type of detector or its efficiency. These properties of this technique are illustrated by measurements.

International Nuclear Information System (INIS)

A basic treatment of the principle of the linac-driven free-electron laser (FEL) is given. The first part of the paper describes the FEL in low-gain approximation, and in the second part the high-gain FEL theory is given. The majority of the treatment describes FELs in one dimensional approximation, neglecting effects by diffraction of radiation and by electron beam emittance. Only in the final section a few remarks on these issues are given. The ambition of the paper is by no means any progress in FEL theory but a clear presentation of basic FEL theory concepts with explicit derivation of the formulae from first principles. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Preheating processed materials and combustion air can result in processing and fuel-efficiency gains in industrial smelting furnaces. For example, fuel consumption in reverberatory furnaces used in copper smelting would drop by as much as 63% at the same throughput by preheating the charge in a countercurrent mode to 1400/sup 0/F by exhaust gases that have an initial temperature of 2500/sup 0/F. Concurrent charge preheating would result in a maximum decrease of 46% in natural gas consumption. An analysis of these gains also provides equations for calculating investment returns and nomographs for optimizing charge-preheating temperatures for reverberatory furnaces.

Energy Technology Data Exchange (ETDEWEB)

This paper details the design, construction and testing of a bayonet tube heat exchanger for use in the process industry and potentially as part of an externally fired combined cycle. Detailed analysis of the system has been undertaken, in particular on the tube side. The data is reported in terms of temperature, pressure, heat gain and heat exchanger effectiveness, over a range of Reynolds numbers and shell side mixture ratios. Much of the heat gained by the tubes is in the annular flow of the bayonet tube. Overall the effectiveness of this system could exceed 70%. (Author)

International Nuclear Information System (INIS)

The simplest high gain free electron laser (FEL) amplifier concept is proposed. A klystron amplifier has the useful property that the various electronic processes take place in separate portions of the amplifier, rather than overlapping as in FEL amplifier with an uniform undulator. The klystron consists of two fundamental parts: succession of 2-3 cascades (modulator), and an output undulator (radiator) in which the modulated electron beam coherently radiates. Each cascade consists of uniform undulator and dispersion section. Unlike distributed optical klystrons, we have a high gain per cascade pass. This has a few consequences. First, klystron gain does not depend on the bunch compression in the injector linac, i.e. maximum gain per cascade pass at high peak beam current is the same at low peak beam current, without compression. Conventional, short-wavelength FEL amplifier and distributed optical ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes a feasibility demonstration of a thermal scanning NDE system for thermal spray coatings. Non-bonds were detected between several types of coatings and their substrates. Aluminum anti-skid coatings having very rough surfaces were included. A technique for producing known non-bond areas for calibrating and demonstrating NDE methods was developed.

International Nuclear Information System (INIS)

An irradiation head with sample holders is described and measurement geometry is reported. Measurements were made for optimizing the distance between the source and the sample and for optimizing the sample diameter. The optimal distance between the source and the sample does not depend on the collimator diameter. The sample diameter should not exceed 30 - 35 mm. Sensitivity and detection limits were determined for Zn, Pb and Br and calibration curves were plotted. (M.D.) 6 figs., 2 tabs., 4 refs.

International Nuclear Information System (INIS)

The spectrometric methods and equipment for "2"0"1Pb and "2"0"1Tl activity control in the prepared thallium chloride in industrial production are described. Estimation of thallium-201 activity is carried out in accord with the square of summary photopeak caused by #gamma#-quanta at 167 keV energy. Attenuation is paid to spectrometer calibration. 5 refs.; 2 figs.; 2 tabs.

Science.gov (United States)

Nov 16, 2010 ... In situ observations are usually made point-wise and the problem in using ...... also discussion of adaptive filtering in Section 4.1.2 of the L4_SM ...... L2-SR -265 SMAP shall provide a Level 1C radar sigma-0 product ...

International Nuclear Information System (INIS)

Decision-making is strongly based on modelling in two of our water supply projects concerning artificial ground water. The model used is a 2-dimensional flow and transport model using the element method. Due to sharp variations in Finnish soils, the modelling process is based on careful and detailed evaluation of basic hydrogeological data before and during model calibration.

International Nuclear Information System (INIS)

Radionuclide x-ray fluorescence analysis was used for the determination of Y, Ba and Cu in thin high-temperature superconducting films. Atomic emission ICP spectrometry was used to estimate the precision and accuracy of analytical results. Reasonable agreement between both methods was obtained when a polynomial calibration curve was applied. (author) 4 refs.; 4 tabs.

Energy Technology Data Exchange (ETDEWEB)

In this paper, the adaptive optics (AO) system at Keck Observatory is characterized. The AO system is described in detail. The physical parameters of the lenslets, CCD and deformable mirror, the calibration procedures and the signal processing algorithms are explained. Results of sky performance tests are presented: the AO system is shown to deliver images with an average Strehl ratio of up to 0.37 at 1.59 {micro}m using a bright guide star. An error budget that is consistent with the observed image quality is presented.

International Nuclear Information System (INIS)

Various examples of applications of these two techniques are described. A part of them are related to the analysis of adsorbed layers formed during gaz-metal interactions. The others are concerned with the analysis of passive films formed during dry and wet corrosion. Problems related to the calibration of these techniques are discussed.

Energy Technology Data Exchange (ETDEWEB)

Resistive analogous meters for spatial and time characteristics in ocean agitation are most often used in practical oceanography in coastal zones but are based on bridge circuits determined to have shortcomings in their linearity range. This shortcoming is eliminated in the circuit of an instrument developed in an oceanographic laboratory (IMIO, Vana). Principle and block circuits are indicated, and static calibration curves are presented as are the correlative functions in the frequency spectrums obtained with the help of sea agitation recorded at a fixed point and at a depth of 6 meters.

International Nuclear Information System (INIS)

In various situations, measurements in prompt gamma neutron activation analysis (PGNAA) are performed to determine the amount of an elemental impurity relative to that of a major constituent of the matrix. An example of this is the measurement of hydrogen concentration in a metallic matrix. In all such cases, a major contributor to the uncertainty in the measurement is the uncertainty in the ratio of the high-purity germanium (HPGe) detector full-energy peak efficiency for the gamma-ray lines of interest (i.e., impurity and matrix gammas). Usually, the ratio is derived from the relative peak efficiency curve, which is determined using isotopic standards that emit multiple gamma ray lines (e.g., "1"5"2Eu) in the energy range <3000 keV, or using prompt gamma radionuclides (e.g., "1"4N, "3"5Cl) in the energy range >3000 keV. In either case, the uncertainty in the ratio of the peak efficiency values derived from such measurements will be on the order of a few percent at best because ...

Energy Technology Data Exchange (ETDEWEB)

We will describe recent improvements to the SPEAR reflectometer at the Manuel Lujan Jr. Neutron Scattering Center at Los Alamos. One of the changes consists of wider convergent, incident-beam, collimation to take advantage of optical imaging for specular scattering. In addition, the instrument now views a partially coupled liquid hydrogen moderator as opposed to the decoupled moderator that was previous in-place. While the wavelength distribution is poorer, it matches the time (wavelength) resolution of the reflectometer more closely with the angular resolution. Since the integrated intensity of the partially coupled moderator is higher than the decoupled moderator, we show a similar gain in incident beam flux on the sample without loss of the ability to separate fringes. The increases in intensity from the moderator gain and the improved collimation combine to allow us to measure reflectivities with good statistics down to 10{sup -4} in a ...

International Nuclear Information System (INIS)

The electron-beam qualities with and without free electron laser (FEL) oscillations were investigated in the compact storage ring NIJI-IV. The peak-electron density in a bunch was suppressed by beam instabilities, so that it was limited to about 1.0 x 10"1"7 m"-"3. The maximum FEL gain estimated for 215 and 300 nm using a well-known one-dimension theory was about 2.8% and 4.6%. The cavity loss at 300 nm was evaluated to be about 2% from the threshold beam current. The bunch length and energy spread with FEL oscillations increased by 1.3 times or more due to bunch heating. The ratio of the FEL gain to a cavity loss estimated from the beam qualities with and without FEL oscillations was almost in accord with the ratio evaluated directly with the measured data of the FEL gain and the cavity loss. (author)

British Library Electronic Table of Contents (United Kingdom)

We study the consumption-portfolio problem in a setting with capital gain taxes and multiple risky stocks to understand how short selling influences portfolio choice with a shorting-the-box restriction. Our analysis uncovers a novel trading flexibility strategy whereby, to minimize future tax-induced trading costs, the investor optimally shorts one of the stocks (or equivalently, buys put options) even when no stock has an embedded gain. Alternatively, an imperfect form of shorting the box can reduce aggregate equity exposure ex post. Given these two short selling strategies, it is common for an unconstrained investor to short some equity while a constrained investor holds a positive investment in all stocks. With no shorting, the benefit of trading separately in multiple stocks is not eco...

International Nuclear Information System (INIS)

Point contact Josephson junctions can function as millimeter wave heterodyne mixers with conversion gain. The best results achieved thus far show a single sideband conversion gain of 1.3 and a mixer contribution to the system noise temperature of 54"0K. Both of these results are approximately 5 times better than the best published figures for cooled Schottky barrier diode mixers operated at the same frequency. The measured noise for a variety of junctions can be expressed as a universal function of the normalized rf frequency #OMEGA# = h#omega#/2eI/sub c/R. It is about a factor 2 larger than the calculated noise arising from the thermal noise in the junction shunt resistance, R. The noise calculation was done for the resistively shunted junction model using an analog junction simulator.

International Nuclear Information System (INIS)

The bandwidth of LIGO-like terrestrial interferometric gravitational wave detectors is set by the pole of the Fabry-Perot cavities within the arms of the Michelson interferometer. This constraint arises because the gain of gravitational wave-induced signal sidebands is limited to frequencies within the linewidth of the cavities. The nature of standard Fabry-Perot cavities is such that one cannot independently adjust for increased gain without suffering a loss of bandwidth. If these quantities could be decoupled, the resulting improvement in bandwidth may lead to viable high frequency detectors. A pair of anti-parallel diffraction gratings within a Fabry-Perot cavity can increase the bandwidth of a LIGO-scale detector by a factor of #approx#1000.

International Nuclear Information System (INIS)

Tunable output wavelength is an important character of a free electron laser (FEL). As generally understood, to alter the wavelength of a high-gain harmonic generation (HGHG) FEL laser, the seed laser must be tunable. A few-cycle, high intensity laser obtained by optical compression usually has pretty broad bandwidth in the spectral domain, which can be used as the seed laser of a HGHG and may open the possibility to approach a HGHG scheme with fully tunable wavelength. In this paper, a HGHG FEL seeded by a few-cycle laser is theoretically discussed and numerically investigated. A few-cycle seed laser significantly influences HGHG FEL performance, especially in output wavelength tuning. For a HGHG FEL seeded by a 4-cycle 786 nm laser, output wavelength tunability range up to 14.9% of the central wavelength 262 nm is observed by adjusting the resonant condition.

International Nuclear Information System (INIS)

Since the advent of the first free electron laser (FEL) in 1976 up to now, a series of principles, configurations and operation modes of these FELs have been devised and partially implemented. The principles refer to transverse FEL, longitudinal FEL, combined FEL, and transverse optical klystron FEL. Configurations may be standard or many-stage and the undulators may be magnetostatic, electrostatic or electromagnetic. The operation regimes may be low-gain Compton type, high-gain Compton type, Raman type, with and without space charge. The operation modes may be the amplification of an external coherent EM radiation, a self-amplified spontaneous emission (SASE), or an oscillator. The paper presents in detail these concepts and the limit between classical approach and the quantum approach of FEL. (Author).

Energy Technology Data Exchange (ETDEWEB)

In order to suppress resonance vibrations of a rotor-shaft of rotating machinery, a rotor-shaft system elastically supported by ball bearings which are installed in electromagnetic actuators are proposed and the design method of some compensatory circuits in the controller to control the electromagnetic actuators in the system are explained. These actuators are controlled by the analog PID (proportional, integral, and derivative) controller. The compensation for nonlinearity of electromagnetic force, the negative stiffness of electromagnet, and the time lag of the coil current are discussed and the effective control circuits are proposed. The rotor-shaft system is replaced by the equivalent two-degree-of-freedom system and both impulse and frequency responses are numerically simulated for several parameters of PD-controller gain. By applying the principle of dynamic absorbers, optimum parameters are calculated. The gains of the control circuit ...

Energy Technology Data Exchange (ETDEWEB)

In this paper, a neural networks (NN) based adaptive sliding mode controller (SMC) is introduced. The selection of SMC feedback gains is normally based on one operating point and thus the performance of the controller away from the design operating point is, of necessity, a compromise. The adaptive SMC is proposed to overcome the limitations imposed on the effectiveness of the SMC under different operating conditions. Neural networks are used for online prediction of the optimal SMC gains when the operating point changes. The proposed method has been applied to a power system stabilizer (PSS) of a single machine power system. Simulation results are included to demonstrate the performance of the proposed control scheme.

CERN Document Server

A set of mode-coupled excitation equations for the slowly-growing amplitudes of dielectric waveguide eigenmodes is derived as a description of the electromagnetic signal field of a high-gain free-electron laser, or FEL, including the effects of longitudinal space-charge. This approach to describing the field basis set has notable advantages for FEL analysis in providing an efficient characterization of such eigenmodes, and in allowing a clear connection to free-space propagation of the input (seeding) and output radiation. A simple transformation converts the coupled differential excitation equations into a set of coupled algebraic equations and yields a matrix determinant equation for the FEL eigenmodes. A quadratic index medium is used as a model dielectric waveguide to obtain an expression for the predicted spot size of the dominant eigenmode, in the approximation that it consists of a single gaussian mode.

Energy Technology Data Exchange (ETDEWEB)

Energy savings performance contracting (ESPC) is now receiving greater attention as a means of implementing large-scale energy conservation projects in housing. Opportunities for such projects exist for military housing, federally subsidized low-income housing, and planned communities (condominiums, townhomes, senior centers), to name a few. Accurate prior (to construction) estimates of the energy savings in these projects reduce risk, decrease financing costs, and help avoid post-construction disputes over performance contract baseline adjustments. This paper demonstrates an improved method of estimating energy savings before construction takes place. Using an engineering model calibrated to pre-construction energy-use data collected in the field, this method is able to predict actual energy savings to a high degree of accuracy. This is verified with post-construction energy-use data from a geothermal heat pump ESPC at Fort Polk, Louisiana. This method also allows ...

CERN Document Server

In the next decade Type Ia supernovae (SNe Ia) will be used to test theories predicting changes in the Dark Energy equation of state with time. Ultimately this requires a dedicated space mission like JDEM. SNe Ia are mature cosmological probes --- their limitations are well characterized, and a path to improvement is clear. Dominant systematic errors include photometric calibration, selection effects, reddening, and population-dependent differences. Building on past lessons, well-controlled new surveys are poised to make strides in these areas: the Palomar Transient Factory, Skymapper, La Silla QUEST, Pan-STARRS, the Dark Energy Survey, LSST, and JDEM. They will obviate historical calibrations and selection biases, and allow comparisons via large subsamples. Some systematics follow from our ignorance of SN Ia progenitors, which there is hope of determining with SN Ia rate studies from 0

Science.gov (United States)

Two-component mixtures of dorzolamide hydrochloride and timolol maleate were assayed by first derivative and ratio derivative spectrophotometric methods. The first method, derivative spectrophotometry, by the zero-crossing measurements, was used due to the drugs closely overlapping absorption spectra. Linear calibration graphs of first derivative values at 250.3 nm for dorzolamide hydrochloride and 315.8 nm for timolol maleate. The second method, is based on ratio first derivative spectrophotometry, the amplitudes in the first derivative of the ratio spectra at 242.9 and at 223.5 nm were selected to determine dorzolamide and timolol maleate in the binary mixture. Calibration graphs were established for 8.0-30.0 microg ml(-1) for dorzolamide hydrochloride and 3.0-24.6 microg ml(-1) for timolol maleate in binary mixture. Good linearity, precision and selectivity were found, and the proposed methods were applied successfully to the pharmaceutical ...

International Nuclear Information System (INIS)

Measurements were carried out for calibration and performance testing of a set of 10 electronic personal dosimeters (EPDs) at the Secondary Standard Dosimetry Laboratory of Sudan. Calibrations were carried out at three X-ray beam qualities described in ISO standard 4037 in addition to 137Cs and 60Co gamma ray beams. The experimental was performed with EPDs mounted on ICRU Slab phantom. X-ray and ?-ray beams were characterized in terms of air kerma free-in-air which were converted to the known delivered personal dose equivalent, Hp(10) using appropriate the air kerma to personal dose equivalent conversion coefficients. Dosimeters tested showed excellent energy and angular response and relative error of indication within the recommended limit for photon energies from 65 keV to 1.25 MeV. The study showed encouraging results for using electronic dosimeters in personal dosimetry.

International Nuclear Information System (INIS)

A pilot project was started in 1977 over the Lake Superior basin to measure water storage on the land area using aerial gamma-ray spectrometry to provide hydrologic information for forecasting inflow to the lake. Two airborne surveys were made, respectively in November 1977 and March 1978 which provided estimates of the increase in snow water equivalent between these surveys. The basin is located on the Canadian Shield and consequently, the gamma radiation count rate is quite variable. The airborne results are compared with ground measurements on selected flight lines and show generally good agreement. Two equipment calibrations in the Ottawa area provided inconsistent parameter values which are consequently also reflected in the results over the Lake Superior basin. The project has demonstrated to-date that the technique can be developed into an operational system for measuring snow cover water equivalent of this vast and remote area by using well ...

Energy Technology Data Exchange (ETDEWEB)

Alanine/EPR Dosimetry system is classified as a reference-standard dosimeter which used to calibrate radiation environments and to calibrate routine dosimeters in absorbed dose range of 1 to 105 Gy. Characteristics of Alanine/EPR dosimetry system are better suitable than routinely used personnel dosimeters for the long term radiation measurement in harsh condition of Nuclear power plant : This system is not significantly affected by temperature and humidity and also has low fading rate. About 1 year ago, Alanine and Lithium compound dosimeters were installed at Wolsung unit 1 for the environment monitoring as a part of equipment qualification program. 35 positions which are most severe and representative cable positions were chosen for radiation and temperature monitoring. The recovered alanine dosimeter in the period of maintenance was measured by E-scan alanine analyzer system, Meanwhile measurement result shows extremely high radiation level ...

Science.gov (United States)

The theory of a method of determination of reactivity from power spectral density measurements with /sup 252/Cf and the results of experiments with a critical assembly mockup of a liquid-metal fast breeder reactor (LMFBR) and with uranium (93.2 wt % /sup 235/U) metal cylinders and a sphere are presented. This method of reactivity determination has an advantage over existing methods in that it determines the reactivity only from properties of the reactor at the subcritical state of interest and thus does not require a calibration near delayed criticality. In these experiments, the reactivity was varied by changing the fissile loading or the amount of neutron absorber inserted; for the LMFBR mockup, the reactivity varied to approximately 75 dollars subcritical, and for the uranium metal assemblies to approximately 30 dollars subcritical. These experiments verified for the first time the predictions of theory that could be tested in the measurements. This method has ...

Energy Technology Data Exchange (ETDEWEB)

We suggest and describe the use of a binary pseudo-random (BPR) grating as a standard test surface for measurement of the modulation transfer function (MTF) of interferometric microscopes. Knowledge of the MTF of a microscope is absolutely necessary to convert the measured height distribution of a surface undergoing metrology into an accurate power spectral density (PSD) distribution. For an'ideal' microscope with an MTF function independent of spatial frequency out to the Nyquist frequency of the detector array with zero response at higher spatial frequencies, a BPR grating would produce a flat 1D PSD spectrum, independent of spatial frequency. For a'real' instrument, the MTF is found as the square root of the ratio of the PSD spectrum measured with the BPR grating to the'ideal,' spatial frequency independent, PSD spectrum. We present the results from a measurement of the MTF of MicromapTM-570 interferometric microscope demonstrating a ...

Energy Technology Data Exchange (ETDEWEB)

In this work, the Calibration-Free approach for Laser-Induced Breakdown Spectroscopy (CF-LIBS) was applied for the first time to radially resolved spectra emitted by a laser-induced plasma. The radial profiles of plasma temperature and electron number density were used to calculate the local relative concentration of the elements of interest. We analyzed a set of profiles of the local spectral emission coefficient obtained previously by means of spatial deconvolution of the spectra from a copper-based alloy (Cu 93, Fe 5, Mn 1, Ni 1 wt.%) laser-induced plasma. A spatially integrated spectrum of the same plasma was also analyzed for comparison purpose. The relative abundance of the minor components Fe, Mn and Ni was calculated. The results obtained from the central region of the plasma were closer to the nominal concentrations than those obtained from the spatially integrated spectrum. However, an increasing deviation was observed towards the plasma edge. It is ...

Energy Technology Data Exchange (ETDEWEB)

We developed a new systematic calibration procedure which was applied to the prediction of the diffusivity, the segregation, and transient enhanced diffusion (TED) of an indium impurity. The TED of the indium impurity was studied using four different experimental conditions. Although indium is susceptible to TED, rapid thermal annealing (RTA) is effective in suppressing the TED effect and maintaining a steep retrograde profile. Like boron impurities, the indium shows significant oxidation-enhanced diffusion in silicon and has segregation coefficients much less than 1 at the Si/SiO{sub 2} interface. In contrast to boron, the segregation coefficient of indium decreases as the temperature increases. The accuracy of the proposed procedure was validated by using secondary ion mass spectrometry (SIMS) data and by using the 0.13-{mu}m device characteristics, such as V{sub th} and I{sub dsat}, for which the differences between simulation and experiment less than 5 %.

Energy Technology Data Exchange (ETDEWEB)

Verification, calibration, and validation (VCV) of Computational Fluid Dynamics (CFD) codes is an essential element of the code development process. The exact manner in which code VCV activities are planned and conducted, however, is critically important. It is suggested that the way in which code validation, in particular, is often conducted--by comparison to published experimental data obtained for other purposes--is in general difficult and unsatisfactory, and that a different approach is required. This paper describes a proposed methodology for CFD code VCV that meets the technical requirements and is philosophically consistent with code development needs. The proposed methodology stresses teamwork and cooperation between code developers and experimentalists throughout the VCV process, and takes advantage of certain synergisms between CFD and experiment. A novel approach to uncertainty analysis is described which can both distinguish between and quantify ...

Energy Technology Data Exchange (ETDEWEB)

In the last two years, the VDMA work group 'Functional security' compiled a qualitative and quantitative procedure for the determination and evaluation of turbo-machine specific risks. With the calibrated risk graph for turbo-machines the requirements (Safety Integrity Level SIL) to the protective functions for turbo-machines (steam turbines, gas turbines, generators and compressors) were determined. With consideration of the legislation, the work group compiled a recommendation for the renewal and/or reconstruction of protective functions with old facilities.

Energy Technology Data Exchange (ETDEWEB)

The reliability of outdoor radon concentration measurements using the track-etch technique is affected by the environmental conditions. Studies have been made to improve stability of nuclear tracks in detector material and to achieve a stable dosemeter response. A dosemeter was developed utilizing chemically etched MA-ND/alpha (CR-39) detector which is thermally insulated and protected against solar irradiation. The calibration showed that its response amounts to 0.21 {plus minus} 0.03 tracks m{sup -2}/Bqm{sup -3} day and was found to be in good agreement with theoretical prediction. (author).

Energy Technology Data Exchange (ETDEWEB)

In Sweden there is a demand for a method of measuring radon in dwellings with high accuracy and at a low cost. A method of determining radon concentration (Bq.m/sup -3/) in dwellings has been developed at the Swedish National Testing Institute. A plastic canister containing activated charcoal has been tested in a radon chamber (volume 20 m/sup 3/) to determine the effects of relative humidity, temperature and exposure time. The activated charcoal in the canister adsorbs radon from the air surrounding the canister. The radon concentration is determined by counting the gamma rays from the decay of radon and daughters. The theory and preliminary results from calibrations and field measurements are reported.

Energy Technology Data Exchange (ETDEWEB)

The procedure followed by the Laboratorio de Metrologia Nuclear in Sao Paulo, Brazil, for the standardization of {sup 242g} Am is described. The calibration system was composed of a 4 {pi} gas-flow proportional counter coupled to a pair of NaI(Tl) crystals operating in coincidence. The samples were produced by irradiating dried aliquots of {sup 241} Am with thermal and epithermal neutrons at the IEA-R1 research reactor. The efficiency tracer technique has been applied using {sup 60} Co as tracer. The beta detection efficiency was changed by external absorbers and extrapolated to unity by linear least square fitting applying covariance methodology. (author)

International Nuclear Information System (INIS)

The neutron elastic magnetic form factor was extracted from quasielastic electron scattering on deuterium over the range Q2=1.0-4.8 GeV2 with the CLAS detector at Jefferson Lab. High precision was achieved with a ratio technique and a simultaneous in situ calibration of the neutron detection efficiency. Neutrons were detected with electromagnetic calorimeters and time-of-flight scintillators at two beam energies. The dipole parametrization gives a good description of the data.

International Nuclear Information System (INIS)

The multi-frequency binary sequence experimental technique has been implemented at the Fast Flux Test Facility for routine surveillance activities. The frequency content of the standard rod-movement sequence has been shown to be sufficient to normalize the data at moderate frequencies. This obviates the need for auxiliary calibration measurements and provides the reactivity worth of the test control rod. Analyses of a series of tests conducted in 1986 illustrate that the rod worths inferred from the tests are consistent with zero-power measurements. Also, the dependence of the prompt feedback time constant on reactor conditions was determined.

International Nuclear Information System (INIS)

Effects of the rapid early-in-life expansion of metal fuel were measured in an irradiation experiment in the Fast Flux Test Facility (FFTF). This important performance/design information was obtainable through the unique combination of a dimensionally stable FFTF oxide core and the calibrated proximity instrumentation associated with the test. These results delineate the time dependence of metal-fuel swelling and provide quantitative estimates of the magnitude of axial fuel swelling in full-length metal-fuel assemblies. Final posttest examination results will define actual fuel column growth levels.

Energy Technology Data Exchange (ETDEWEB)

Until April 2007 the Major Atmospheric Gamma ray Imaging Cherenkov (MAGIC) telescope used a 300 MSamples/s flash analog-to-digital converter (FADC) system to sample the shaped photomultiplier tube (PMT) signals produced by the captured Cherenkov photons of air showers. Different algorithms to reconstruct the signal from the read-out samples (extractors) have been implemented and are described and compared. Criteria based on the obtained charge and time resolution/bias are defined and used to judge the different extractors, by applying them to calibration, cosmic and pedestal signals. The achievable charge and time resolution have been derived as functions of the number of incident photo-electrons.

Energy Technology Data Exchange (ETDEWEB)

Intensities of {gamma}-transitions emerging from the EC decay of {sup 203}Pb were measured precisely. The obtained relative {gamma}-intensities are 100%(279.2keV), 4.14+-0.08%(401.3keV) and 0.932+-0.022%(680.5keV). The 279.2 and 680.5keV level feeding {beta}-branching ratios were deduced to be 95.3+-0.1 and 4.7+-0.1% respectively. {sup 203}Pb is suggested for calibration purposes. (author).

Science.gov (United States)

We outline the process for determining the morphology of subsurface epithelial cell nuclei using depth-resolved light scattering measurements. The measurements are accomplished using a second generation angle-resolved low coherence interferometry system. The new system greatly improves data acquisition and analysis times compared to the initial prototype system. The calibration of the new system is demonstrated in scattering studies to determine the size distribution of polystyrene microspheres in a turbid sample. The process for determining the size of cell nuclei is discussed by analyzing measurements of basal cells in a sub-surface layer of intact, unstained epithelial tissue.

Energy Technology Data Exchange (ETDEWEB)

A beam position monitoring system has been implemented in the first third of the SLC linac which provides a complete scan of the trajectory on a single beam pulse. The data is collected from the local micro-computers and viewed with an updating display at a console or passed on to application programs. The system must operate with interlaced beams so the scans are also interlaced, providing each user with the ability to select the beam, the update rate, and the attenuation level in the digitizing hardware. In addition each user calibrates the hardware for his beam. A description of the system architecture will be presented. 6 refs., 4 figs.

Energy Technology Data Exchange (ETDEWEB)

Diffusion of radon in a bed of activated charcoal is described by diffusion equations. An analytical solution of these equations is presented for the case of constant radon concentration in the atmosphere. The solutions are given separately for short term and long term exposure. An analytical form of the calibration constant f for long term exposure and constant radon concentration in air, was found. A numerical method and computer code based on the method of finite elements is developed for the case of variable radon concentration in air. This program simulates radon adsorption by the activated charcoal bed, enabling determination of sensitivity. The dependence of sensitivity on different parameters, such as temperature, thickness of the charcoal, etc. was studied using this program. (orig.) 10 refs.

Energy Technology Data Exchange (ETDEWEB)

This project investigated new techniques for improving seismic event locations derived from regional and local networks. The technqiues include a new approach to empirical travel-time calibration that simultaneously fits data from multiple stations and events, using a generalization of the kriging method, and predicts travel-time corrections for arbitrary event-station paths. We combined this calibration approach with grid-search event location to produce a prototype new multiple-event location method that allows the use of spatially well-distributed events and takes into account correlations between the travel-time corrections from proximate event-station paths. Preliminary tests with a high quality data set from Nevada Test Site explosions indicated that our new calibration/location method offers improvement over the conventional multiple-event location methods now in common use, and is applicable to more general ...

International Nuclear Information System (INIS)

High energy physics facilities must monitor the radiation doses received by their personnel. This monitoring can only be effective if the radiation detection devices can be calibrated with a good degree of accuracy. Radiation fields are usually composed of several types of radiation, including gamma rays, beta radiation, neutrons, etc. The neutron detection instruments respond not only to the neutrons coming directly from the source but also those scattered from the floor, walls, and ceiling. The amount of neutron scattering varies from site to site depending on the construction materials and layout of the building. The purpose of this study was to determine the scattered neutron fraction in the central volume of the calibration mezzanine of the Radiation Physics Calibration Facility (RPCF) at the Fermi National Accelerator Laboratory (Fermilab). At Fermilab, radiation workers dosimeters use CR39 for neutron detection, ...

Science.gov (United States)

The clinical manifestation of wounds of the heart is determined by the mode, site and size of the injury as well as the structure of the pericardial and myocardial lesion. Diagnosis can be confirmed by ECG and echocardiography. Only 20% of the patients with penetrating wounds of the heart live for more than 30 minutes. Pericardio-centesis should be used only to gain time for a safe sternotomy, cardiac decompression and suture of the wound of the heart. An aggressive surgical approach is mandatory. Cardiopulmonary bypass is necessary only to correct of concomitant lesions. PMID:1983618

Energy Technology Data Exchange (ETDEWEB)

The wavelength dependence of the threshold in an InGaP-InAlGaP vertical cavity surface emitting laser is investigated using a microscopic theory of the semiconductor gain medium. Good agreement is found between experiment and theory for the minimum threshold lasing wavelength for a range of laser structures.

Energy Technology Data Exchange (ETDEWEB)

A decoupled characteristic between the damping of a specific swing mode and the stabilizer gain of the corresponding machine in multimachine power systems is identified. Using this decoupled characteristic a power system stabilizer (PSS) synthesis approach which is based on the phase compensation concept is verified on a 9-machine system and the dynamic performance of this system is significantly improved. This method is proved to be effective, simple and it can provide useful guidance for the PSS field tuning.

Science.gov (United States)

Steady-state and transient behavior of the longitudinally pumped semiconductor laser is theoretically investigated by using a rate-equation model with distributed gain and photon density. Conditions necessary for bistable operation are derived. Dependencies of such major switching characteristics as turn-on and turn-off powers, delay, and rise times on laser parameters are examined. Influences of spontaneous radiation, impurities, and Auger recombination are studied. The results offer an explanation for the observed nonlinear behavior of face-pumped lasers.

Energy Technology Data Exchange (ETDEWEB)

In this work, the thermal performance of a conventional collector is improved by inserting porous substrates at the inner walls of the collector tubes. The porous substrates improve the convective heat transfer coefficient between the tube wall and the fluid. This improvement is investigated numerically and its effects on the efficiency and the useful gain of the collector are evaluated. It is found that inserting the porous substrate may raise the collector efficiency considerably, especially at high values of the overall heat loss coefficient.

UK PubMed Central (United Kingdom)

The Wnt signaling pathway is a robust regulator of skeletal homeostasis. Gain-of-function mutations promote high bone mass, whereas loss of Lrp5 or Lrp6 co-receptors decrease bone mass. Similarly, mutations...Full Text Available

CERN Document Server

We obtain a simple derivation of the optimal quantum state estimation of a two-level system using the no-signaling principle. In particular, we show that the no-signaling principle determines the unique form of the guessing probability, independently to a given figure of merit such as the fidelity or the information gain. This proves that optimal measurements for a two-level quantum system is the same for almost all figures of merit.

Energy Technology Data Exchange (ETDEWEB)

This paper will describe the application of power generation by the use of microturbine technology by Capstone Turbine Corporation throughout South America. The purpose of this paper is to describe the technology and the experience gained over the last six years. The microturbines are power generation systems that produce energy from a diverse range of liquid or gaseous fuels. The generator is driven by a small gas turbine with a common shaft for the rotors of the generator and the engine. (author)

Energy Technology Data Exchange (ETDEWEB)

We use the method of Padg approximants and Fourier transform techniques to treat analytically the problem of transverse and longitudinal mode evolution in FELs. We obtain simple relations providing a transparent understanding of the dynamic of pulse propagation effects and of transverse mode guiding. We discuss the interplay with inhomogeneous broadening effects and derive gain formulae including longitudinal and transverse mode couplings.

Energy Technology Data Exchange (ETDEWEB)

This 2001 edition of the guide to UK renewable energy companies examines the geothermal heat pump sector, and discusses the technology involved, installations of geothermal heat pumps, the activity in the UK market with increased interest in UK geothermal heat pump products from abroad, and developments in the building sector. The UK government's increased support for the industry including its sponsorship of the Affordable Warmth programme, and the future potential of ground source systems are discussed.

UK PubMed Central (United Kingdom)

Outbreaks of disease attributable to human error or natural causes can provide unique opportunities to gain new information about host-pathogen interactions and new leads for pathogenesis research....Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A low voltage FEL operating at 130 kV which can be run cw with a continuous electron beam current level up to 12 mA has been constructed for the X-Band microwave range (8-12 GHz). In this poster, we will report on the dependence on time, after the electron beam is switched on, of the growth and competition of those longitudinal modes in the cavity having nett gain.

Energy Technology Data Exchange (ETDEWEB)

Since many years, people take care of hazardous consequences of a non controlled economic growth and the sustainable development concept gains on one. This situation leads to consequences in the building industry and in the energy policy: buildings insulation in consideration, demand of consultants. In this framework, the partnership between Gaz De France and CICF has to be built. (A.L.B.)

CERN Document Server

In this paper, we extend the diversity and multiplexing tradeoff (DMT) analysis from point-to-point channels to cellular systems to evaluate the impact of inter-cell interference on the system reliability and efficiency. Fundamental tradeoff among diversity order, multiplexing gain and inter-cell interference intensity is characterized to reveal the capability of multiple antennas in cellular systems. And the detrimental effects of the inter-cell interference on the system performance of diversity and multiplexing is presented and analyzed.

Energy Technology Data Exchange (ETDEWEB)

The new power cars currently being built for commuter services in the Stockholm area have a number of innovative features. Manufacturer Alstom-LHB, who developed the vehicle based on experience gained with the LIREX experimental train, is also offering this model in continental Europe. (orig.)

International Nuclear Information System (INIS)

The paper will report the experience gained in the implementation of the national assistance projects, including the detailed assessment of the national situation compared to the ITWG Model Action Plan, the upgrading of the technical skills, the training of national experts and the joint analysis of nuclear material at ITU. The status of the work with the 13 future Member States to the European Union will also be reported on during the conference

Energy Technology Data Exchange (ETDEWEB)

In the paper is studied the physics of a free electron laser (FEL) based on a two-frequency undulator (TFU) which induces large non linear effects, especially on the spectral dynamics. These effects are analyzed in an extended formalism where the spontaneous emission, the low-gain regime and the strong-field saturation regime are studied. Numerical simulations show that the optimized TFU generates a laser field having both a large extraction efficiency and a narrow spectrum.

Energy Technology Data Exchange (ETDEWEB)

A non-linear analysis of a Cerenkov maser is presented. The system consists of a ring configuration of a cylindrical waveguide filled with a dielectric material. A single transverse-magnetic mode is assumed to propagate in the system. A low-density pencil electron beam travels in part of the ring, confined by a strong axial magnetic field. Using the single-particle description for the beam and the wave equation for the field, we obtain a set of two coupled non-linear differential equations describing the slowly varying amplitude and phase of the electromagnetic mode. The gain per path is assumed to be small and the spatial growth of the field is neglected. The resulting time dependent amplitude includes the exponential gain of the linear stage and the saturation to its maximum value. The time dependent frequency is also calculated. The two equations are combined to a single Van Der Pol equation with a non-linear restoring force. This ...

International Nuclear Information System (INIS)

We propose to investigate the spontaneous emission of radiation arising out of the interaction of a relativistic electron beam with a metallic grating (the Smith-Purcell effect). The work will concentrate, primarily, in the 50-120 #mu#m part of the infrared spectrum and will be an extension of the work begun by the Oxford-Dartmouth-Essex collaboration; one of the early objectives of the project will be to develop a quantitative understanding of the power spectrum of the emitted radiation over a wide range of emission angles. In particular, the limits of relativistic peaking of forward directed emission will be investigated. The electron beam will be produced by laser irradiation of a metallic cathode in the terminal of a small Van de Graff accelerator located in the Technische Universitaet, Muenchen. Beam energies will be in the range of 2 - 4 MeV. Initial tests on photoproduction of electrons have yielded 10 mA pulses with a width of about 20 ns. The electron pulse length is long ...

Energy Technology Data Exchange (ETDEWEB)

The rise of spam in the last decade has been staggering, with the rate of spam exceeding that of legitimate email. While conjectures exist on how spammers gain access to email addresses to spam, most work in the area of spam containment has either focused on better spam filtering methodologies or on understanding the botnets commonly used to send spam. In this paper, we aim to understand the origins of spam. We post dedicated email addresses to record how and where spammers go to obtain email addresses. We find that posting an email address on public Web pages yields immediate and high-volume spam. Surprisingly, even simple email obfuscation approaches are still sufficient today to prevent spammers from harvesting emails. We also find that attempts to find open relays continue to be popular among spammers. The insights we gain on the use of Web crawlers used to harvest email addresses and the commonalities of techniques used by spammers open ...

Science.gov (United States)

This study reports on an examination of the effectiveness of a reading intervention for adults with disabilities in a vocational rehabilitation setting. Participants were 57 adults with disabilities and low reading skills enrolled at the Reading Clinic at the Michigan Career and Technical Institute. As part of a 3-year research and demonstration grant evaluation project, participants received an individualized reading intervention that targeted phonological processing, orthographic pattern recognition, and comprehension for adults with disabilities and low reading levels. The particular program incorporated fluency exercises at every level of the structured, explicit, and systematic intervention curriculum. Results showed that participants made moderate to large gains in passage reading accuracy and comprehension during the course of the intervention. Gains in passage reading rate were not statistically significant. Results are discussed in ...