Energy Technology Data Exchange (ETDEWEB)

Application, design, and installation of the cable line in steel pipe with oil under pressure for 500 kV is considered. The cable construction and design specifications are presented. Manpower requirements for the installation of the cable, extending from the hydrogenerators to the outdoor switchgears or to the change point where they are connected to overhead power lines, are discussed and data provided.

Energy Technology Data Exchange (ETDEWEB)

Results obtained on induced current and voltage caused by a high voltage transmission lines running parallel at a trolley bus contact lines, are presented. A computer program in Basic language, was developed to calculate the electric induction, problems of safety, a theoretical development and mathematical model of the electric factors between two lines (inductor and induced) are also discussed. 11 figs., 1 tab., 8 refs.

Energy Technology Data Exchange (ETDEWEB)

A detailed description is given of the design, fabrication, and installation of oil-filled 500-kV cable lines used for the first time in the USSR for transmitting electric power from step-up transformers installed several meters from the hydroelectric generators to an outdoor distribution system or a junction point at which they are connected to overhead power transmission lines. These lines are 950 to 1050 m long and they are placed at levels differing by 45 m along the route. These lines can transmit power as great as 630 MV.A.

International Nuclear Information System (INIS)

The magnitude of electric and magnetic fields around a high voltage three-phase transmission line was studied. A three-phase transmission circuit with parallel conductors produces rotating elliptic electric and magnetic fields. This study investigated the optimum arrangement of the phase conductors to minimize the maximum value of the magnetic flux density and to minimize the intensity of the resultant electric field. Two different types of high voltage double circuit transmission lines of 400 kV were considered. The optimum arrangement of the phase conductors was determined. It was concluded that the optimum arrangement can be easily applied to already constructed high voltage transmission lines by properly interchanging the phase conductors at the substations. 10 refs., 1 tab., 4 figs.

Energy Technology Data Exchange (ETDEWEB)

It is well known that the lightning protection of transmission lines is exclusively relying on their correct initial design. Although detailed engineering studies are usually performed by electric power utilities for the design of new transmission lines, there are reported cases where the design is based simply on tradition or on utilities' standardization policy. In this paper, the lightning protection of high-voltage transmission lines is faced as an optimization problem where optimum design parameters are calculated for the lines, relating their cost with the lightning failures' cost, aiming to reduce or even eliminate lightning failures. The optimization method considers all the available protection means, i.e. ground wires and surge arresters. In order to validate the effectiveness of the proposed method, it is applied on several operating Hellenic transmission lines of 150 kV carefully selected among others due to their high failure rates ...

Science.gov (United States)

Sixty-Hz magnetic field exposures were measured for 45 adult residents of Maine. Thirty of the subjects resided near rights-of-way (ROWs) with either 345- and 115-kV transmission lines, or ROWs with only 115-kV transmission lines; fifteen resided far from any transmission lines. Personal exposure data for a single 24-hour period was acquired with the EMDEX. The EMDEX's event-marker button was used to partition exposures into Home and Away components. Also, three area measurements were taken for each subject during the personal exposure measurement period: (1) 24-hr fixed-site bedroom measurement with a second EMDEX; (2) Spot measurements in at least three rooms of every residence; and (3) Spot measurements outside each residence. Residence near transmission lines highly loaded during the measurement period was associated with increased Home and Total exposure relative to a far-away population. Average exposure level while away from ...

Energy Technology Data Exchange (ETDEWEB)

As a central supervision authority the National Electrical Safety Board (Elsaekerhetsverket) has the main responsibility for the safety of high voltage power lines and other power electric equipment. It is therefore also responsible for questions concerning the effects of power frequency magnetic fields on the environment. According to the rules it is not allowed to draw overhead power lines with a voltage exceeding 1000 V above buildings. Their minimum distance to buildings must not be below 5 m. For regions comprised by rural development plans the directions prescribe a minimum distance of 10 m between buildings and high voltage transmission lines with a voltage of 55 kV or more. The publication of two large epidemiological studies about exposure to magnetic fields and cancer in Sweden in autumn 1992 has brought magnetic fields problems to general notice again. A statement on health risks form electromagnetic fields was issued by SSI in ...

CERN Document Server

Heterogeneous base stations (e.g. picocells, microcells, femtocells and distributed antennas) will become increasingly essential for cellular network capacity and coverage. Up until now, little basic research has been done on the fundamentals of managing so much infrastructure -- much of it unplanned -- together with the carefully planned macro-cellular network. Inter-cell coordination is in principle an effective way of ensuring different infrastructure components behave in a way that increases, rather than decreases, the key quality of service (QoS) metrics. The success of such coordination depends heavily on how the overhead is shared, and the rate and delay of the overhead sharing. We develop a novel framework to quantify overhead signaling for inter-cell coordination, which is usually ignored in traditional 1-tier networks, and assumes even more importance in multi-tier heterogeneous cellular networks (HCNs). We derive ...

Energy Technology Data Exchange (ETDEWEB)

This report presents the data and results of a site specific case study comparing costs of an overhead line with an underground circuit traversing the same route. The costs used for the overhead line are actual numbers for a line scheduled to be built by a utility. The underground circuit costs were developed using the same criteria of line rating, contingencies, and location. Often cost comparisons between overhead and underground lines are made using figures taken from studies with widely varying assumptions. This project attempts to provide a comparison by studying the costs of overhead and underground lines following the same route and using the same design assumptions. Caution must be used, however, in extending the results of this study beyond its original intent. It is site-specific and may be representative of only one area of the country. 9 refs., 23 figs., 18 tabs.

KoreaScience (Korea)

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KoreaScience (Korea)

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Energy Technology Data Exchange (ETDEWEB)

Audible noise from corona discharge had been identified as one of the most important factors in the design of conductor configurations for high-voltage transmission lines. 500 kV and above. Therefore this paper describes audible noise characteristics of 6 X 480 mm{sup 2} conductor bundle in KEPRI 765 kV Test Line and Corona Cage. Prediction formula for audible(corona) noise on a 765 kV Transmission Line was developed using this results. (author). 4 refs., 4 figs., 4 tabs.

Energy Technology Data Exchange (ETDEWEB)

The flow of current inside a conductor leads to its overheating. This conductor is also submitted to other climatic phenomena, such as wind, sun light and ambient temperature. The knowledge of this overheating is important to ensure a functioning temperature compatible with the materials used for the conductor manufacturing and with the dip of overhead power lines above the ground and buildings. On the other hand, according to the Laplace works, the flow of current inside parallel conductors induces electromagnetic forces inside them, proportional to the product of currents in both conductors. In the case of short-circuit between aerial power lines or between flexible cables, electrodynamical stresses (traction and flexion) are applied to insulators and holders and important swinging of the lines can be observed. These stresses can be extremely important and must be considered in the design of overhead lines. These two phenomena are analyzed in ...

Energy Technology Data Exchange (ETDEWEB)

The APMP/TCRI Dosimetry Working Group performed the APMP.RI(I)-K3 key comparison of measurement of air kerma for medium-energy x-rays (100 kV to 250 kV) between 2000 and 2003. In total, 11 institutes took part in the comparison, among which 8 were APMP member laboratories. Two commercial cavity ionization chambers were used as transfer instruments and circulated among the participants. All the participants established the 100 kV, 135 kV, 180 kV and 250 kV x-ray beam qualities equivalent to those of the BIPM. The results showed that the maximum difference between the participants and the BIPM in the medium-energy x-ray range, evaluated using the comparison data of the linking laboratories ARPANSA and PTB, is less than 1.4%. The degrees of equivalence between the participants are presented and this comparison confirms the calibration capabilities of the ...

Science.gov (United States)

The Knight shift of vanadium (KV) in fine V3Si particles was studied. The average diameter (\\bar{d}) ranged from 60 to 8000 A. The strong temperature dependence of the KV characteristic of high-Tc A-15 compounds was weakened in the particles. KV at 77 K increased with a decrease in \\bar{d}. The above-mentioned trends were consistent with a broadening of the sharp peak in the electronic density of states around the Fermi energy in particles resulting from a perturbation of the surface.

Energy Technology Data Exchange (ETDEWEB)

In 1969, the authors started R and D on a polypropylene laminated paper (PPLP) as a new low-loss insulating paper for oil-filled (OF) cables. Through the material research and the trial manufacture of 275 kV OF cable and four years of long-term field test, PPLP has reached the stage of commercial use. This paper introduces a summary of the history of the development of PPLP, the characteristics of PPLP and cable, the results of long-term field test of 275 kV cable, and other relevant data.

Energy Technology Data Exchange (ETDEWEB)

As an interim report on the study on vibration of transmission lines when gust is blowing, this paper introduces events of confused and other contacts between transmission lines, photographing of transmission line vibration, physical measurement on transmission line response, and development of simulation software. Events of confused contacts of high-voltage transmission lines with overhead ground wires have the following common conditions: gust blows nearly perpendicularly to the line direction; no obstacles exist in upwind directions; the wind blows upward or downward against high-voltage transmission lines; and size of the high-voltage transmission lines is 25 mm{sup 2}. According to photographs of transmission line vibration, it appears that gust caused a high-voltage transmission line on the upwind side to jump resulting in confused contact with the overhead ground wire. The physical measurement uses such devices as an image recording ...

Energy Technology Data Exchange (ETDEWEB)

Overhead persistent surveillance systems are becoming more capable at acquiring wide-field image sequences for long time-spans. The need to exploit this data is becoming ever greater. The ability to track a single vehicle of interest or to track all the observable vehicles, which may number in the thousands, over large, cluttered regions while they persist in the imagery is very desirable. Typically, this imagery has many thousands of pixels on a side and is characterized by lower resolutions (e.g. {approx}0.5 meters/pixel to {approx}2.0 meters/pixel) and lower frame rates (e.g. {approx} sub-Hz to several Hz). We describe our ultra-scale capable implementation of a multiple-vehicle tracking algorithm for overhead persistent surveillance imagery. This work builds upon an earlier report, where now the algorithm has been modified for improved performance and has been substantially improved to handle much larger datasets in a much shorter time.

Energy Technology Data Exchange (ETDEWEB)

Since 1985 the operating sections of the 1200 kV AC Ekibastuz-Urals transmission system were used for a variety of field studies on a wide range of technological problems associated to high voltage transmission lines. The tests performed confirmed correctness of the main engineering and design decision made at development stage and demonstrated that such transmission lines are reliable and efficient. 3 figs.

UK PubMed Central (United Kingdom)

The rapidly activating and inactivating voltage-dependent outward K⁺ (Kv) current, I_A, is widely expressed in central and peripheral neurons. I_A has long been...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

By way of introduction, the author describes the electrical equipment of the power station on the River Traun and then lists the main features of the electrical systems such as generators, transformers, the power transmission systems as, e.g., the generator leads, the 8 kV switch plant, the 110 kV oil-filled cable as well as the station-service, control, protection and monitoring systems. The control of the headwater level and of the mechanical systems of the barrage is described in detail.

Energy Technology Data Exchange (ETDEWEB)

This report describes the work carried out to analyze and design a circuit for use in 1200 kV gas insulated substations. The first part of the project was devoted to a thorough analysis of the requirements for the circuit breaker from the standpoint of the electrical system in which it would operate. A conceptual design was selected and all of the components of the circuit breaker were designed, modeled and verified. Finally a plan was prepared for the construction of a complete circuit breaker.

Energy Technology Data Exchange (ETDEWEB)

Corona from bare conductors of electrical overhead power lines is studied in this article. Its origin, as well as, its bad influences over communication systems are both studied, yet. Line`s models are defined, in order to be able the examination of Corona on line`s cables. Formulas for the surface electrical gradient calculations are shown. (author) 2 refs.

International Nuclear Information System (INIS)

Purpose: To report our clinical experiences with on-board imager (OBI) kV image verification for cranial stereotactic radiosurgery (SRS) and radiotherapy (SRT) treatments. Methods and Materials: Between January 2007 and May 2008, 42 patients (57 lesions) were treated with SRS with head frame immobilization and 13 patients (14 lesions) were treated with SRT with face mask immobilization at our institution. No margin was added to the gross tumor for SRS patients, and a 3-mm three-dimensional margin was added to the gross tumor to create the planning target volume for SRT patients. After localizing the patient with stereotactic target positioner (TaPo), orthogonal kV images using OBI were taken and fused to planning digital reconstructed radiographs. Suggested couch shifts in vertical, longitudinal, and lateral directions were recorded. kV images were also taken immediately after treatment for 21 SRS patients and on a weekly ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes the dielectric and accelerated aging tests on prototype {plus minus}500 kV dc oil-filled self-contained cables. The extensive test program was required to evaluate the High-Voltage cables for the St. Lawrence river crossing of the {plus minus}500 kV Quebec-New England HVDC power transmission system. The paper relates the main elements of the test program. It describes the required insulation levels, the characteristics of the cables supplied by three different manufacturers, as well as the cables' installation for the type tests and accelerated aging tests. Details of the test program and procedures followed to carry out the tests are given. Findings of the tests are also reported.

Energy Technology Data Exchange (ETDEWEB)

A new 500 kV one cycle electric circuit breaker with a mininum interrupting time of 12.5 m sec is described. The breaker, associated with a 1/4 cycle relay, insures a one cycle interruption. 5 refs.

UK PubMed Central (United Kingdom)

The purpose of this study was to assess the effect of a 735-kV transmission line on the electric and magnetic field exposures of people living at the edge of the line's right of way. Exposure of 18...Full Text Available

International Nuclear Information System (INIS)

Until 1990, in Tuscany, salt pollution of anti-salt insulators installed on high-tension transmission lines had led to rare breakdowns. On the contrary, in the last months of 1990, in most of Tuscany, following a strong libeccio wind coming from the Tyrrhenian Sea, and due to a long period of drought, salt deposits accumulated on the insulators of the high-voltage transmission lines (380 kV, 220 kV and 132 kV). This phenomenon not only took place in the coastal areas near Livorno, Pisa and Grosseto, but also in areas far away from the sea such as Florence, Prato, Arezzo and Siena. Following this, several high-tension lines, and whole sections of 380 kV electric stations went out of order, damaging the stations' equipment, insulators on the lines, and in particular porcelain insulators. The maintenance operations that were immediately undertaken consisted in washing operations, first focussed on ...

Energy Technology Data Exchange (ETDEWEB)

An electrostatic beam steering mechanism (ESM) has been designed and tested to deflect negative ion beams consisting of multi-beamlets. A steering angle of 10 mrad was obtained within the deviation of less than 1 mrad by biasing two electrodes at 0.5 kV and -0.75 kV for 120 keV H{sup -} ion beam. The current flowing to the positive electrode was no more than 10% of the beam current at a pressure of 2.8x10{sup -5} Torr. (author)

Energy Technology Data Exchange (ETDEWEB)

The HVDC link across the English Channel, which was brought into service in 1986, has several innovative features. Techniques used in its construction together with recent developments have consolidated the viability of HVDC links for a variety of applications. Outlines the main features of the scheme, including the benefits of interconnecting the British and French 400 kV AC power systems; integration of the UK converter system to the 400 kV AC grid; the DC submarine cables; convertor equipment (particularly the UK installation); and future HVDC developments. 6 refs.

Energy Technology Data Exchange (ETDEWEB)

There are many sources of population exposures to power-frequency (50/60 Hz) electric and magnetic fields including household appliances and wiring, neighborhood distribution circuits, and high-voltage transmission lines. Bioeffects studies were unable to demonstrate that exposures to power-frequency fields can affect public health. Researcher have likewise been unable to show that the health effects of such exposures are negligible. State and federal regulatory agencies are, therefore, grappling with questions of whether and how to regulate the sitting or design of new extra high-voltage transmission lines so as to control the ground-level fields to which people are exposed. The purpose of this dissertation is to illuminate some of the exposure-related aspects of these question. A taxonomy of the relationship between field encounter and effect is developed to clarify the meaning of terms such as exposure and dose in the power-frequency context. The major inputs to models of population ...

CERN Document Server

Studies on the large scale peer-to-peer (P2P) network like Gnutella have shown the presence of large number of free riders. Moreover, the open and decentralized nature of P2P network is exploited by malicious users who distribute unauthentic or harmful contents. Despite the existence of a number of trust management schemes in the literature for combating against free riding and distribution of malicious files, these mechanisms are not scalable due to their high computational, communication and storage overhead. These schemes also do not consider effect of trust management on quality-of-service (QoS) of the search. This paper presents a trust management scheme for P2P networks that minimizes distribution of spurious files by a novel technique called topology adaptation. It also reduces search time since most of the queries are resolved within the community of trustworthy peers. Simulation results indicate that the trust management overhead due ...

Energy Technology Data Exchange (ETDEWEB)

Overhead, high power transmission lines have secured rights of way on agricultural lands in Minnesota. The economic impact of such utility crossings, including effects on land price, was investigated. Sale records and survey data were analyzed. Buyers, sellers, and brokers were interviewed concerning inconvenience, radio interference, appearance, and loss of irrigation possibilities due to the transmission lines. In nine affected sales, there was only one case in which less money was indicated for the farm because of the presence of a transmission line.

Energy Technology Data Exchange (ETDEWEB)

The micropulse lidar (MPL) is a ground-based optical remote sensing system designed primarily to determine the altitude of clouds overhead. The physical principle is the same as for radar. Pulses of energy are transmitted into the atmosphere; the energy scattered back to the transceiver is collected and measured as a time-resolved signal. From the time delay between each outgoing transmitted pulse and the backscattered signal, the distance to the scatterer is infered. Besides real-time detection of clouds, post-processing of the lidar return can also characterize the extent and properties of aerosol or other particle-laden regions.

Energy Technology Data Exchange (ETDEWEB)

Recent advances in steering algorithms have made it possible to accurately control electron beam position in storage rings, implement fast and slow feedback systems, and in some cases detect hardware errors. In practice, however, the program operator would like to reduce the overhead of selecting variables and constraints and to easily view the data. To simplify the process, we constructed an interactive orbit control program in MATLAB [1]. The program modules are easily adapted to new algorithms or beam lines. This paper describes the program functionality and architecture.

Energy Technology Data Exchange (ETDEWEB)

The theme of the conference was 'The paradox: today's coal technologies versus tomorrow's promise'. The sessions covered: today's technologies, tomorrow's potential; economic stability; energy security; transition to sustainable energy future; new coal power technologies leading to zero emission coal; existing power plants - improved performance through use of new technology; and carbon capture and storage R & D - challenges and opportunities. Some of the papers only consist of the viewgraphs/overheads.

Energy Technology Data Exchange (ETDEWEB)

The Berliner Kraft- u. Licht (BEWAG)AG have been conducting investigations during the last several years on a 110 kV low-pressure oil-filled high-power cable with a water cooled conductor and a load capacity of 950 MVA at 110 kV. After successful transport of the cable drums (weight: 16 metric tons; diameter: 4.9 m) from the manufacturing in Cologne, West Germany, to Berlin (West), and after laying of the cable over a 300 m stretch, the commissioning tests in accordance with IEC and VDE* standards have been concluded, and several loadings with a current of 5000 A have been performed. Now, after completion of various improvements in the test system, preparations are underway for initiation of long-term testing over a period of approx. 18 months.

Energy Technology Data Exchange (ETDEWEB)

In the 150 kV power system of the Dutch energy utility MEGA Limburg cross-country faults have caused problems in the protection of high voltage transmission lines. A cross-country fault is the simultaneous presence of two single-phase earth connections in different phases and places within the grid. These cross-country faults can lead to the incorrect operation of a number of distance relays, which could result in the faulty disconnection of high voltage transmission lines. To gain an insight into these problems, the transient phenomenon in the power system during cross-country faults were studied. For this purpose, the simulation program EMTP (ElectroMagnetic Transients Program) has been used. Simulation models of the 150 kV power system and the measuring system of a distance relay were developed within EMTP. 7 figs., 1 ill.

Energy Technology Data Exchange (ETDEWEB)

Beginning in 1972 low-pressure cables filled with MN-4 oil produced by the Yaroslav Petroleum Processing Plant arrived at the Leningrad Cable Network of the Leningrad Rayon Power Administration. Lines formed with these cables have been successfully used. The parameters of the oil in them have not changed with respect to the values present when the lines were placed in operation. However, from here on filling in of the 110 to 220 kV input lines of low and high pressure will be accomplished with MN-4 oil produced by the Gorkiy Petroleum Processing Plant. Because petroleum from various fields and the properties of the oil produced from it are unlike, samples were taken from some elements of the lines filled in with MN-4 oil. The results of the tests are described.

Energy Technology Data Exchange (ETDEWEB)

ABB High Voltage Cables AB started the MPS (More Power Submarine cables) project in 1993 with a view to exploring new technology opportunities. The goal is to design and type test a submarine HVDC cable for a capacity of 1200 MW at 600 kV. On the day before ABB announced its success in winning the contract for the world`s largest ever submarine HVDC link project for the gigantic Bakun project in Malaysia, ABB Power Systems described progress to date at a symposium in Karlskrona. The proceedings included a test demonstration on an extruded cable which eventually broke down at a stress of over 935 kV -not in the insulation itself but in the end terminations. The electric field was in excess of 200 kV/mm which is higher than ever before reported. (UK)

Energy Technology Data Exchange (ETDEWEB)

This paper reports on a flexible dimensionaly flush joint for 500kV aluminum-sheathed oil-filled cables capable of being assembled, pulled an installed in a similar manner to cables at site which has been developed. This joint is intended for use at intermediate points on long bridges or tunnels where local assembly and installation of conventional joints would be difficult. In developing the joint various novel and original techniques have been employed, including the flexible flush jointing of segmental conductors, the flexible jointing of paper insulation by a combination of wrapping-back and stepping methods, plus on-site aluminum sheath corrugating and sealing methods.

Energy Technology Data Exchange (ETDEWEB)

The Kernel Polynomial Method (KPM) has been successfully applied to tight-binding electronic structure calculations as an O(N) method. Here the authors extend this method to nonorthogonal basis sets with a sparse overlap matrix S and a sparse Hamiltonian H. Since the KPM method utilizes matrix vector multiplications it is necessary to apply S{sup {minus}1}H onto a vector. The multiplication of S{sup {minus}1} is performed using a preconditioned conjugate gradient method and does not involve the explicit inversion of S. Hence the method scales the same way as the original KPM method, i.e. O(N), although there is an overhead due to the additional conjugate gradient part. The authors show an application of this method to defects in a titanate/platinum interface and to a large scale electronic structure calculation of amorphous diamond.

Energy Technology Data Exchange (ETDEWEB)

BC Hydro has been assessing and upgrading its facilities and implementing response alternatives to potential damage resulting from a major earthquake. This paper reviews the utility`s seismic evaluation of its overhead transmission system, focusing on the Lower Mainland area where most of the tall critical river-crossing towers are located. The paper gives an overview of the geologic environment of the Lower Mainland and outlines the criteria used for assessing existing structures for their ability to withstand design seismic loads. It then describes the investigation and analysis methods used in the assessment, including geotechnical field tests, ground response analysis, determination of soil liquefaction potential, and dynamic analysis of structures and piles. Options for seismic upgrades are discussed and illustrated by the case of the Pitt River crossing, where tower foundations were reinforced with steel pipe piles.

Energy Technology Data Exchange (ETDEWEB)

The effects of fine-particle C, such as diesel soot, on the optical properties of urban haze in the visible wavelength range were explored to determine the dominant effects and to see if simple parameters (such as visual range in green) provide an adequate measure of these effects. It is known that fine-particle C absorbs more strongly in the blue than in the red, so that when it is mixed with a white pigment, the resulting gray can appear somewhat brown. The possibility of a similar effect in urban hazes was investigated, but found not to occur. When the sun is overhead, the near-horizon sky chromaticities caused by mixtures of fine-particle C and non-absorbing aerosol can also be produced by non-absorbing aerosols alone. It is shown that absorbing aerosol will darken the horizon sky, and a simple equation for the radiance of the horizon sky is derived. The effect of absorbing aerosol on the distance at which white and black objects can be seen is calculated.

CERN Document Server

Many secure communication libraries used by distributed systems, such as SSL, TLS, and Kerberos, fail to make a clear distinction between the authentication, session, and communication layers. In this paper we introduce CEDAR, the secure communication library used by the Condor High Throughput Computing software, and present the advantages to a distributed computing system resulting from CEDAR's separation of these layers. Regardless of the authentication method used, CEDAR establishes a secure session key, which has the flexibility to be used for multiple capabilities. We demonstrate how a layered approach to security sessions can avoid round-trips and latency inherent in network authentication. The creation of a distinct session management layer allows for optimizations to improve scalability by way of delegating sessions to other components in the system. This session delegation creates a chain of trust that reduces the overhead of establishing secure ...

International Nuclear Information System (INIS)

The nation's electric power system would be subject to induced surges in the event of a high altitude nuclear burst. The HEMP would be coupled to overhead power lines and cause severe overvoltage to components connected to the line. This paper discusses the design of pulsed power equipment needed to simulate this induced EMP. A facility is described which is capable of testing the vulnerability of components by applying appropriate voltage and current waveforms. The pulser can provide waveforms under a variety of test conditions to meet the requirements of different types of components. A 3-5 MV Marx pulser is described. It has the capability of generating a fast rising voltage followed by two distinct exponential decays. The testing of components, charged with their normal voltage is also described.

Energy Technology Data Exchange (ETDEWEB)

A fast multipole transformation is adapted to the evaluation of summations that occur in global climate calculations when transforming between spatial and spherical harmonic representations. For each summation, the timing of the fast multipole transformation scales linearly with the number of latitude gridpoints, but the timing for direct evaluations scales quadratically. In spite of a larger computational overhead, this scaling advantage renders the fast multipole method faster than direct evaluation for transformations involving greater than approximately 300 to 500 gridpoints. Convergence of the fast multipole transformation is accurate to machine precision. As the resolution in global climate calculations continues to increase, an increasingly large fraction of the computational work involves the transformation between spatial and spherical harmonic representations. The fast multipole transformation offers a significant reduction in computational time for these ...

International Nuclear Information System (INIS)

A new polarized electron gun for use on the SLC at SLAC has been built and tested. It is a diode gun with a laser driven GaAs photocathode. It is designed to provide short (2ns) pulses of 10 A at 160 kV at 120 Hz. The design features of the gun and results from a testing program on a new and dedicated beam line are presented. Early results from operation on the SLC will also be shown.

Science.gov (United States)

Silicone-rubber washers function as damping and articulating elements in cast-aluminum spacers that separate bundle subconductors in each phase of extra-high-voltage transmission lines. Spacer/dampers are located every 3 ft. along transmission lines on Canada's first operational 500 and 735 kV system.

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.

International Nuclear Information System (INIS)

The Department of Energy (DOE), Western Area Power Administration (Western) proposes to consolidate segments of two transmission lines near the Gering Substation in Gering, Nebraska. The transmission lines are both located in Scotts Bluff County, Nebraska. The transmission lines are both located in Scotts Bluff County, Nebraska, within the city of Gering. Presently, there are three parallel 115-kilovolt (kV) transmission lines on separate rights-of-way (ROW) that terminate at the Gering Substation. The project would include dismantling the Archer-Gering wood-pole transmission line and rebuilding the remaining two lines on single-pole steel double circuit structures. The project would consolidate the Gering-Stegall North and Gering-Stegall South 115-kV transmission lines on to one ROW for a 1.33-mile segment between the Gering Substation and a point west of the Gering Landfill. All existing wood-pole H-frame structures would be removed, and the ...

UK PubMed Central (United Kingdom)

The aim of the study was to investigate the possible acute effects of exposure to electric and magnetic fields. Twenty six experienced linesmen, aged 25 to 52, were studied during two working days while...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Remotely-fielded unattended sensor networks generally must operate at very low power--in the milliwatt or microwatt range--and thus have extremely limited communications bandwidth. Such sensors might be asleep most of the time to conserve power, waking only occasionally to transmit a few bits. RFID tags for tracking or material control have similarly tight bandwidth constraints, and emerging nanotechnology devices will be even more limited. Since transmitted data is subject to spoofing, and since sensors might be located in uncontrolled environments vulnerable to physical tampering, the high-consequence data generated by such systems must be protected by cryptographically sound authentication mechanisms; but such mechanisms are often lacking in current sensor networks. One reason for this undesirable situation is that standard authentication methods become impractical or impossible when bandwidth is severely constrained; if messages are small, a standard digital signature or HMAC will ...

Energy Technology Data Exchange (ETDEWEB)

We present an efficient parallel algorithm and its implementation for computing the diagonal of $H^-1$ where $H$ is a 2D Kohn-Sham Hamiltonian discretized on a rectangular domain using a standard second order finite difference scheme. This type of calculation can be used to obtain an accurate approximation to the diagonal of a Fermi-Dirac function of $H$ through a recently developed pole-expansion technique \\cite{LinLuYingE2009}. The diagonal elements are needed in electronic structure calculations for quantum mechanical systems \\citeHohenbergKohn1964, KohnSham 1965,DreizlerGross1990. We show how elimination tree is used to organize the parallel computation and how synchronization overhead is reduced by passing data level by level along this tree using the technique of local buffers and relative indices. We analyze the performance of our implementation by examining its load balance and communication overhead. We show that our implementation ...

Energy Technology Data Exchange (ETDEWEB)

The recent attempt to degassify a self contained liquid filled (SCLF) cable in Ontario Hydro is described. In September 1989, there was a high pressure alarm on one phase of a SCLF 115 kV cable circuit. The direct buried cable circuit is about 1,890 m long with two joints and was installed in 1968. Oil samples from the cable had 10 to 12% gas content with high levels of hydrogen, methane, and ethane, and very low levels of carbon monoxide, carbon dioxide, and acetylene. From these results it was concluded that the gas was generated by low energy electrical discharges and the paper insulation was not degraded. Various utilities and cable manufacturers were contacted to find if they had experienced similar problems. The cable duct oil was flushed and gasified and the successive oil samples were analyzed in order to locate the gassing site. The joints were examined and oil samples were taken through holes drilled in the cable sheath. From the test results the problem ...

International Nuclear Information System (INIS)

Development of the Conawapa-Winnipeg power transmission complex in Manitoba includes five interrelated transmission and conversion facilities. Environmental and socio-economic assessment work done to date on one component of this system (the upgrading of the Southern Receiver System) is described. This system is composed of a network of high voltage transmission lines and station facilities serving power demand in Winnipeg and southern Manitoba. The upgrading involves three main elements: energizing a second 230 kV ac circuit on an existing tower line running from the proposed Riel Station site to the existing St. Vital Station; constructing a new double-circuit 230 kV tower line on the same existing right-of-way between St. Vital and the Riel site area; and installing an additional transformer and other necessary equipment at St. Vital and other stations affected by the upgrade. The environmental impacts of these projects are generally not ...

Energy Technology Data Exchange (ETDEWEB)

Transmission terminations available today are very reliable, but they need to be. In the field, they are continually exposed to pollution and extremes of ambient temperature. In many cases, they are in the rifle sights of vandals. In contrast, cable joints - often cited as the weakest links from an electrical viewpoint - are generally protected from physical damage underground and many of the short cable systems being installed in the US today can be built without joints. All cable systems need terminations - mostly to air-insulated equipment. At 69 through 138 kV, there is intense competition among manufacturers to supply terminations for solid-dielectric cable that are low in cost, reliable, and require a minimum of skill to install. Some utilities are looking also for terminations that fit a range of cable sizes; terminations that do not contain liquid that can leak out; and terminations that are shatter-proof. All of these improvements are available in the US ...

Energy Technology Data Exchange (ETDEWEB)

Feed-forward (FF) artificial neural networks (ANN) and radial basis function (RBF) ANN methods were addressed for evaluating the lightning performance of high voltage transmission lines. Several structures, learning algorithms and transfer functions were tested in order to produce a model with the best generalizing ability. Actual input and output data, collected from operating Hellenic high voltage transmission lines, as well as simulated output data were used in the training, validation and testing process. The aims of the paper are to describe in detail and compare the proposed FF and RBF ANN models, to state their advantages and disadvantages and to present results obtained by their application on operating Hellenic transmission lines of 150kV and 400kV. The ANN results are also compared with results obtained using conventional methods and real records of outage rate showing a quite satisfactory agreement. The proposed ANN methods can be ...

International Nuclear Information System (INIS)

The paper describes transportation cost of the nuclear off-peak power for a hydrogen production based on water electrolysis in Japan. The power could be obtainable by substituting hydropower and/or fossil fueled power supplying peak and middle demands with nuclear power. The transportation cost of the off-peak power was evaluated to be 1.42 yen/kWh when an electrolyser receives the off-peak power from a 6kV distribution wire. Marked reduction of the cost was caused by the increase of the capacity factor. (author)

Energy Technology Data Exchange (ETDEWEB)

This paper reported on a study in which partial discharge (PD) measurements were performed on 6 underground transmission cable circuits to determine the effectiveness of PD measurements on fluid fill cables. The cables were between 37 and 56 years old. PD activity was detected from the terminations of H11L and H3L Cable 2. However, for cables from H3L Basin TS to Mill Street junction, PD activity was detected originating from within the main cable insulation.

Energy Technology Data Exchange (ETDEWEB)

The major distributor and retailer of electrical power to Auckland, New Zealand, is Mercury Energy Limited. Following the sequential failure of the four 110kV underground cables, two gas-filled and two oil-filled, which supply the central business district, power was interrupted for 29 days from the 20th February 1998. A government inquiry was instituted, to examine what happened, why, and what lessons could be drawn for the future. Inadequacies in Mercury Energy`s cable maintenance and operating procedures were identified. The findings of the inquiry and its recommendations are reported. (UK)

British Library Electronic Table of Contents (United Kingdom)

We operate a new NEC 250kV single-stage accelerator mass spectrometer (SSAMS) next to our established 5MV tandem. This permits good comparison of 14C-AMS and challenges SSAMS performance. Initial SSAMS ion-optical deficiencies have been addressed by shimming the injection magnet and 3permil 14C/13C measurement with background limited by sample chemistry is routine. Higher-precision analysis is also achievable. A problematic measurement interference remains, however. The small spectrometer was procured to add measurement capacity, and for experiments with positive ions, but is now the preferred instrument for both convenience and measurement quality.

Energy Technology Data Exchange (ETDEWEB)

In dual-energy projection radiography with double exposures, rapid energy switching is mandatory to eliminate motion artifacts, but it is costly for use in a clinical environment. We developed a system with practical exposure intervals at reasonable cost by modifying a condenser-type X-ray generator. A commercially available system for digital radiography (Fuji Computed Radiography, FCR) was used to subtract images. This report dealt with technical factors to obtain adequate kV and mAs settings in this technique.

Energy Technology Data Exchange (ETDEWEB)

An improved method to design suitable compensating schemes for extra high voltage transmission lines is presented. The technique is general and effective and will greatly facilitate the design of the optimal compensation scheme for extra high voltage transmission lines. The technique is illustrated for a typical 500 kV system. The equations developed here for voltage maxima and minima along the transmission line eliminate the need for point-to-point computation of the voltage profile. The controversy existing in the literature over the problem of making a choice between pi and tee configurations has been removed and it is established with a mathematical proof that the tee configuration requires compensating elements of lower ratings.

Energy Technology Data Exchange (ETDEWEB)

Construction of high voltage transmission lines in a difficult hilly terrain within the limited time frame calls for the adoption of modern management tools for controlling the progress. The activity on node network system for such works, in which parallel and overlapping activities are involved is highly useful and is being used in Himachal Pradesh State Electricity Board. This network system has helped the Board to provide an effective and efficient mode of progress reporting at all levels of functioning. A remarkable example is the control of construction of 190 km - 200 kV dc transmission line within four years and six months.

Energy Technology Data Exchange (ETDEWEB)

The paper begins with an introduction on the reasons that lead to the use of HVDC submarine cable links. The main aspects for the choice of direct current are presented as well as the advantages deriving from the utilization of submarine cables. The second part is dedicated to a discussion on the various type of insulation that could be used in power cables and their possible application to HVDC submarine cables. In the following there is a description of the main characteristics and technical details of some particular project that at present time (1995) are in progress. Two projects are briefly presented: Spain-Morocco, a 26 km long interconnection for the transmission, in a first phase, of 700 MW from Spain to Morocco at 400 kV a.c. by means of three cables, plus one spare, of the fluid filled type. The cables are designed for a future change to d.c. 450 kV, allowing a transmission of 500 MW each (i.e., 2 GW total). One of the peculiarities ...

International Nuclear Information System (INIS)

Johnston Atoll (JA) is a small (270-ha), but strategic, US possession in the Pacific Ocean, which was previously used in nuclear weapons testing. Nuclear devices were launched by missile for detonations at very high altitudes. In 1962, one missile failed on the launch pad and two failed overhead. The devices were destructed without nuclear yield, but transuranium (TRU) elements were dispersed. Cleanup was swift and incomplete. A 2-ha area was placed under radiological controls and restricted from use due to residual contamination. Planning was begun in 1983 for a total JA cleanup to provide additional (unrestricted) land to meet future requirements. A TRUe soil cleanup is programmed to begin at JA in 1988 utilizing a full-scale mining plant. The plant should be able to process all contaminated soil by 1992 and produce less than #approx# 2000 m"3 of concentrated waste. This cleanup will increase the amount of land available for unrestricted use and provide a source ...

Science.gov (United States)

This paper summarizes the progress to date by CH2M HILL and the UKAEA in development of a parametric modelling capability for estimating the costs of large nuclear decommissioning projects in the United Kingdom (UK) and Europe. The ability to successfully apply parametric cost estimating techniques will be a key factor to commercial success in the UK and European multi-billion dollar waste management, decommissioning and environmental restoration markets. The most useful parametric models will be those that incorporate individual components representing major elements of work: reactor decommissioning, fuel cycle facility decommissioning, waste management facility decommissioning and environmental restoration. Models must be sufficiently robust to estimate indirect costs and overheads, permit pricing analysis and adjustment, and accommodate the intricacies of international monetary exchange, currency fluctuations and contingency. The development of a parametric cost ...

CERN Document Server

We consider relay selection technique in a cooperative cellular network where user terminals act as mobile relays to help the communications between base station (BS) and mobile station (MS). A novel relay selection scheme, called Joint Uplink and Downlink Relay Selection (JUDRS), is proposed in this paper. Specifically, we generalize JUDRS in two key aspects: (i) relay is selected jointly for uplink and downlink, so that the relay selection overhead can be reduced, and (ii) we consider to minimize the weighted total energy consumption of MS, relay and BS by taking into account channel quality and traffic load condition of uplink and downlink. Information theoretic analysis of the diversity-multiplexing tradeoff demonstrates that the proposed scheme achieves full spatial diversity in the quantity of cooperating terminals in this network. And numerical results are provided to further confirm a significant energy efficiency gain of the proposed algorithm comparing to ...

Science.gov (United States)

This is a multi-color 230-page textbook covering analog electronics at the upper-division level. Text material is intended for a full-year sequence at 2-3 credits per term. Topics include: amplifier thermal considerations; class A IC output stage; class B complementary amplifier; class A and Class B single-ended amplifiers; feedback amplifiers; gain margin and phase margin; compensation; oscillators (Wien-bridge, Hartley, Colpitts, Pierce); piezoelectric crystals, single-pole circuits; single-pole pulse response; single-pole rectangular wave response; comparators; Schmitt triggers; 555 timers; multivibrators; RC attenuators; compensated attenuators; principles of dc-dc conversion; capacitor-based converters; buck converter; boost converter; buck-boost converter. The text is in Adobe Acrobat 4.0 format, complete with Acrobat index. Large font size allows the text to be used with overhead transparencies, on screen with an Acrobat Reader, or in print form.

CERN Document Server

Resource coordination and interference management is the key to achieving the benefits of femtocell networks. Over-the-air signaling is one of the most effective means for distributed dynamic resource coordination and interference management. However, the design of this type of signal is challenging. In this letter, we address the challenges and propose an effective solution, referred to as coded single-tone signaling (STS). The proposed coded STS scheme possesses certain highly desirable properties, such as no dedicated resource requirement (no overhead), no near-and-far effect, no inter-signal interference (no multi-user interference), low peak-to-average power ratio (deep coverage). In addition, the proposed coded STS can fully exploit frequency diversity and provides a means for high quality wideband channel estimation. The coded STS design is demonstrated through a concrete numerical example. Performance of the proposed coded STS is evaluated through ...

CERN Document Server

Although the current Internet Protocol known as IPv4 has served its purpose for over 20 years, its days are numbered. With IPv6 reaching a mature enough level, there is a need to evaluate the performance benefits or drawbacks that the new IPv6 protocol will have in comparison to the well established IPv4 protocol. Theoretically, the overhead between the two different protocols should be directly proportional to the difference in the packet's header size, however according to our findings, the empirical performance difference between IPv4 and IPv6, especially when the transition mechanisms are taken into consideration, is much larger than anticipated. We first examine the performance of each protocol independently. We then examined two transition mechanisms which perform the encapsulation at various points in the network: host-to-host and router-to-router (tunneling). Our experiments were conducted using two dual stack (IPv4/IPv6) routers using end nodes running ...

Energy Technology Data Exchange (ETDEWEB)

A historical review on insulated cables for power transmission, is presented, beginning with impregnated paper insulation, oil filled cables and natural rubber cables. High density and chemically reticulated polyethylene were then used for high voltage and very high voltage cables; the advantages of polyethylene compared to impregnated paper cables are discussed, which led to research programs at EDF on various themes concerning the optimization of polyethylene cables: dielectric properties and reliability, thermomechanical behaviour, thermal ageing of materials, testing methods (acceptance dielectric test and long duration temperature test); utilization of low- and high-density and chemically reticulated polyethylene for 225 kV cables is discussed

Energy Technology Data Exchange (ETDEWEB)

This Final Environmental Impact Statement and Environmental Impact Report (Final EIS/EIR) has been prepared to meet the requirements of the National Environmental Policy Act (NEPA) and the California Environmental Quality Act (CEQA). The Proposed Action includes the construction, operation, and decommissioning of a 48 megawatt (gross) geothermal power plant with ancillary facilities (10-12 production well pads and 3-5 injection well pads, production and injection pipelines), access roads, and a 230-kilovolt (kV) transmission line in the Modoc National Forest in Siskiyou County, California. Alternative locations for the power plant site within a reasonable distance of the middle of the wellfield were determined to be technically feasible. Three power plant site alternatives are evaluated in the Final EIS/EIR.

Energy Technology Data Exchange (ETDEWEB)

New values of the factors required to convert the reading of a radiation dosemeter calibrated in terms of air kerma (or exposure) into absorbed dose to water for medium-energy x-radiation were given in a code of practice published by the International Atomic Energy Agency in 1987. These are not considered to possess sufficient support from other sources. It is therefore recommended that the F-factors given or codes of practice should continue to be used. Values of backscatter factors for low-energy x-radiation (below 140 kV) in Supplement 17 of the British Journal of Radiology appear to be inaccurate. New values based on Monte Carlo calculations, and supported by new experimental data, are given for use in radiotherapy. (author).

International Nuclear Information System (INIS)

The time and dose characteristics of the electron and X-ray radiations of a tube, connected to a subnanosecond mega volt accelerator, are measured. By the pulse of the accelerating voltage of #>=# 600 kV with duration of #approx =# 0.3 ns the tube generates approximately 5 x 10"1"2 electrons pulse. The current amplitude equals approximately 5 kA/pulse and the radiation dose-about 5 kGy/pulse. The X-ray radiation dose from the tantalum external target constitutes 0.15 Gy/pulse. The prototypes of the electron and X-ray tubes sufficiently lower volumes, opening new applications in the technique and medicine, are developed

International Nuclear Information System (INIS)

Full text: A method to measure noise power spectrum of a full field digital mammography system is presented. The effect of X-ray radiation dose, size and configuration of region of interest on normalized noise power spectrum (NNPS) was investigated. Flat field images were acquired using RQA-M2 beam quality technique (Mo/Mo anode-filter, 28 kV, 2 mm Al) with different clinical radiation doses. The images were cropped at about 4 cm from the edge of the breast wall and then divided into different size of non-overlapping or overlapping segments. NNPS was determined through de trending, 2-D fast Fourier transformation and normalization. Our measurement shows that high radiation dose gave lower NNPS at a specific beam quality. (author)

Energy Technology Data Exchange (ETDEWEB)

In the rf-driven free-electron laser (FEL) at the Los Alamos National Laboratory, there are two pulsed-power rf modulators as sources for two tandem, side-coupled 20-MeV linear accelerators. The rf power used to control the cavity fields is supplied by two 5.5-MW modulating anode klystrons operating at a center frequency of 1300.2 MHz. The modulation of the 125 kV klystron is achieved by using a triode switch tube that provides a pulse width up to 300 ..mu..s and a pulse repetition rate up to 10 Hz. This paper describes the present configuration of these two duplicate systems and presents plans for meeting the requirements of future rf FEL experiments at Los Alamos. 12 refs., 5 figs.

International Nuclear Information System (INIS)

Mini-LIA is a miniature of a linear induction accelerator developed by China Academy of Engineering Physics and Tsinghua University in 2007. It has been constructed with a thermionic cathode in an electron injector and a metglas core in the induction accelerator cavities. A double-pulsed electron beam was produced for the first time in China on the Mini-LIA with a thermionic cathode in the electron gun and a metglas core in the induction accelerator cavities. A double-pulsed beam current of more than 1.1A was obtained on condition of 80 kV double-pulsed high voltage produced by pulsed power system supplying to the injector and accelerating modules. Some primary experiments for measuring the parameters of Mini-LIA has been performed, and some beam characterizations of Mini-LIA are presented. Further improvement is underway. (authors)

British Library Electronic Table of Contents (United Kingdom)

Harmonics bred from loads are mainly odd order because the current waveforms have half-wave symmetry. Since the even harmonics are negligibly small, they generally are not measured in electric power systems. However, even harmonics were measured at a 500/275/154 kV substation in Hokuriku Electric Power Company after a transmission line fault was corrected. The even harmonics caused malfunctions of protective digital relays because the relays used 4th harmonics at the input filter as the automatic supervisory signal. This paper describes mechanisms of generation of the even harmonics by comparing the measured waveforms with the ATP-EMTP simulation results. Analysis of these results has clearly shown that there are three different mechanisms of generation of even harmonics. The first mechani...

Energy Technology Data Exchange (ETDEWEB)

Restructuring of power system has changed the traditional planning objectives and introduced challenges in the field of Transmission Expansion Planning (TEP). Due to these changes, new approaches and criteria are needed for transmission planning in deregulated environment. Therefore, in this paper, a dynamic expansion methodology is presented using a multi-objective optimization framework. Investment cost, congestion cost and reliability are considered in the optimization as three objectives. To overcome the difficulties in solving the non-convex and mixed integer nature of the optimization problems, a Non-Dominated Sorting Genetic Algorithm (NSGA II) approach is used followed by a fuzzy decision making analysis to obtain the final optimal solution. The planning methodology has been demonstrated on the IEEE 24-bus test system and north-east of Iran national 400 kV transmission grid to show the feasibility and capabilities of the proposed algorithm in electricity ...

International Nuclear Information System (INIS)

A two module electron beam source operating over a wide range of output parameters has been designed and fabricated to be used in conjunction with a pair of electron beam sustained CO_2 lasers. Each module comprised a grid-controlled thermionic electron beam gun including a compact grid pulser for control of the electron beam, a 250 kV thyratron switched modulator for acceleration of the electron beam, a 1 kHz filament heater and a complex computerized control system. The system was designed to reliably produce 45 #mu#s wide electron pulses of 150-200 keV energy, operate at repetition rates of 1-10 pps and current densities of 5-20 mA/cm"2. Additional parameters are listed. The high voltage cathode assembly employs 132 thoriated tungsten filaments distributed over the area of the 250 cm x 10 cm output window. The cathode assembly including the control grids is supported by two high voltage ceramic bushings in a stainless steel vacuum chamber. For acceleration of ...

Energy Technology Data Exchange (ETDEWEB)

While underground power transmission lines have become to use CV cables as the mainstream, existing facilities still use OF cables. Factors of OF cable deterioration include heat cycles during operation and surge intrusion. As a method to diagnose this deterioration in insulation, characteristics tests are performed by collecting insulation oil in a cable connection box. The insulation oil collection work has been done conventionally with the power line stopped to prevent danger from induction voltage. A power uninterruptible oil collection tool was developed recently. The tool consists mainly of an insulator made of epoxy resin, wherein a connection box connector is rotated and loosened by operating an insulating operation rod, with the structure not contacted directly with metallic sheath, so that insulation oil can go through the oil collecting tool and gets collected. Discussions were given on the tool to be capable of collecting samples for analyzing water content in oil. As a ...

International Nuclear Information System (INIS)

Network security is a discipline that focuses on securing networks from unauthorized access. Given the Escalating threats of malicious cyber attacks, modern enterprises employ multiple lines of defense. A comprehensive defense strategy against such attacks should include (I) an attack detection component that deter- mines the fact that a program is compromised, (2) an attack identification and prevention component that identifies attack packets so that one can block such packets in the future and prevents the attack from further propagation. Over the last decade, a significant amount of research has been vested in the systems that can detect cyber attacks either statically at compile time or dynamically at run time, However, not much effort is spent on automated attack packet identification or attack prevention. In this paper we present a unified solution to the problems mentioned above. We implemented this solution after the forward engineering of Open Source Security Information ...

CERN Document Server

All MBI bending magnets in each of the two LHC injection transfer lines will be powered in series. The limited output voltage of existing power converters lead to an unusual coil design avoiding external return bus-bars by combining two overlapping half-coils, electrically separated, with 3 1/2 turns each in a monolithic structure. The voltage between turns in one coil can reach up-to 3.6 kV. The coil has been designed with particular care for obtaining high interturn and ground insulation. Flux-free soldering of connections with plug-in cone sleeves is applied, allowing to execute water cooled current connections as prolongation of the coil conductor. Epoxy compound polymerization in the impregnation mould is obtained by passing overheated water in regulated cycles through the water circuit of the coil conductor. We describe the design basics as well as various test results of pre-series and series produced coils. (4 refs).

Energy Technology Data Exchange (ETDEWEB)

When chest radiographs are obtained using an anti-scatter grid in a mobile x-ray unit by Fuji Computed Radiography (FCR), right lung densities may differ from left lung densities owing to misalignment caused by an oblique x-ray beam. Such misalignment is considered to be caused by factors such as the shape of the bed and angle of the x-ray tube. Misalignment is especially frequent when exposure is carried out in the sitting position. Although a low-ratio grid has been reported to offer improvement, the misalignment is not completely eliminated. Therefore, we used a copper plate without a lattice feature instead of grid, and examined the results. The copper plate was found to have the ability of a grid to eliminate radiation scatter, and, furthermore, to offer the physical capabilities of a grid as determined by Carlin's new grid assessment method. Image quality was demonstrated through contrast manipulation to be equal to that obtained by grid use. Further, optimal conditions ...

International Nuclear Information System (INIS)

A 750 J plasma coaxial accelerator is used to produce plasma using air at 0.2 torr pressure and 8 kv charging voltage. The discharge current and voltage traces showed that the total circuit inductance was about 1750 ?H. The experimental results showed that the plasma sheath reached the muzzle after 6 ?s with velocity equal to 4 cm/?s, after then it decreased, while the simulation model showed that the plasma sheath reaches the muzzle with velocity of 3 cm/?s and after one microsecond it increases to reach about 4 cm/?s after 12 ?s then it decreased. The plasma temperature measurements showed that the plasma sheath reached the muzzle with temperature of about 9 eV and increase to reach about 12 eV after 8.5 ?s then after it decrease. The simulation model showed that the plasma temperature at the muzzle is about 10.5 eV and continue to increase to reach 17.5 eV after 12 ?s then it decrease.

International Nuclear Information System (INIS)

We have studied both theoretically and experimentally a new scheme of active pulse compression in a free electron laser (FEL) amplifier. The pulse compression scheme presented here is the following. A frequency-chirped pulse is injected into the FEL interaction region. Because of the high gain and narrow bandwidth of the FEL interaction, only the resonant frequency band of the pulse is actively amplified, resulting in a short pulse of high power coherent radiation at the output of the laser. For our experimental parameters (beam voltage #approx =# 150 kV, current #approx =# 5.0 A, wiggler period #approx =# 3.5 cm and gain #approx =# 10 dB), pulses of a few nanoseconds were generated at #approx =# 10 GHz after an interaction length of 2.30 m, in good agreement with theoretical expectations. For the same input pulses (width > 100 ns, frequency chirp #alpha#/2#pi# #approx =# 5 MHz/ns), the obtention of such compression ratios would require hundreds of meters of ...

Energy Technology Data Exchange (ETDEWEB)

The authors investigated the application of pulsed corona discharge process to the removal of SO{sub 2} and NO{sub x} from industrial flue gas of an ioron-ore sintering plant. This study was performed on a pilot scale, which is the most advanced demonstration of this process. The flow rate of 5000 m{sup 3}/h of the flue gas was successfully treated. The electrode structure of the corona reactor is the same with that of conventional electrostatic precipitator. The authors made use of magnetic pulse compression technology to produce repetitive high voltage pulse. Pulse width (full width at half maximum) was reduced to less than 1 {micro}s by connecting a resister in parallel with the corona reactor. An inductor was added to the resister in series to minimize the loss by restricting the current flowing through the resister. By this way, they were able to deliver pulse power with peak voltage of 110 kV and peak current of 2.3 kA to the corona reactor. Chemical ...

Energy Technology Data Exchange (ETDEWEB)

Until now, monitoring of power transformers focussed mainly large generator and network transformers. Siemens goes a step ahead and provides a system especially developed and designed for small and medium power transformers, e.g. for the 100 kV level. This low cost version could be achieved by restriction to really necessary measuring quantities. This allows to realize also for small and medium power transformers an online monitoring including an estimation of aging and as an option an early warning to avoid unexpected failures. (orig.) [German] Die Ueberwachung (Monitoring) von Leistungstransformatoren war bisher vor allem fuer Maschinentransformatoren und grosse Netzkuppeltransformatoren in der Diskussion. Siemens geht einen Schritt weiter und stellt nun auch ein System bereit, das speziell fuer kleine und mittlere Leistungstransformatoren, z.B. der 110-kV-Spannungsebene, konzipiert ist. Diese kostenguenstige Variante wurde durch Beschraenkung auf die aus ...

Energy Technology Data Exchange (ETDEWEB)

The Nilsson Plate High Frequency Adaptation of the Static Electrification Monitor developed by Electric Research and Management, Inc. for EPRI has demonstrated that the Nilsson Plate can be utilized as a practical high frequency antenna to record partial discharge activity within a transformer. Tests in the ABB factory at Muncie, IN on a 650 MVA, 345/20.9 kV, three-phase unit step-up transformer for TU Electric showed the Nilsson plate detecting partial discharge activity. Although this test was the first attempt at using the Nilsson plate in this manner, and in spite of higher than expected electrical noise levels, the data demonstrated that partial discharges can be detected. The tests also demonstrated that corona activity external to the transformer was not recorded by the plate. Some development work needs to be completed to eliminate the noise source from other monitors on the Static Electrification monitor, and to utilize state-of-the-art computer ...

Energy Technology Data Exchange (ETDEWEB)

A methodology for assessing the lightning performance of Hellenic high voltage transmission lines has been developed. Its main advantage is that the analysed transmission line is divided into regions and the analysis is conducted separately for each one region, taking into account the individual characteristics, which exist in each one of them. The developed approach intends to offer more accuracy in the assessment of lightning performance of Hellenic high voltage transmission lines and of similar lines, where they run at the same time through a plain region, a coastline and/or a mountainous region. The aims of the paper are to describe in detail the proposed methodology and to present results obtained by its application on operating Hellenic transmission lines of 150 and 400 kV. The computed results are compared with the results produced by another software tool published in the technical literature and with the real records of outage rate showing a good ...

International Nuclear Information System (INIS)

The barrier glow discharge between two planar electrodes, covered with dielectric, is studied under high-voltage pulsed power supply. Wide applications of such type of discharges, in particular, for ozone production, stimulated a number of investigations in this direction. In this work we investigated the dependence of ozone concentration on the duration and the rate of pulse rise of the applied voltage. The thyristor converter circuit with the shortening of input pulses on the base of the saturable throttle was used for the realization of this task. The output pulses with amplitude up to 15 kV, repetition frequency of 1 kHz, pulse duration of 0.3 #mu#s (or 7 #mu#s) and the rate of pulse rise of 0.1 #mu#s were generated with this scheme. Measurements of the ozone concentration produced in the air mixture have shown that its value increased by factor two with variation of the rate of pulse rise from 0.5 #mu#s to 0.1 #mu#s (for pulse duration of 7 #mu#s). The ...

CERN Document Server

Each of the two LHC injection kicker magnet systems must produce a kick of 1.3 T.m with a flattop duration variable up to 7.86 microseconds, and rise and fall times of less than 900 ns and 3 microseconds, respectively. A kicker magnet system consists of four 5 Ohm transmission line magnets with matching terminating resistors, four 5 Ohm Pulse Forming Networks (PFN) and two Resonant Charging Power Supplies (RCPS). Nine PFNs, together with associated switch tanks, and dump switch terminating resistors have been built at TRIUMF and all have been tested at high voltage (54 kV) to ensure that the performance is within specification. This paper describes the HV measurements, compares these results with low voltage measurements and analyses the pulse performance of the PFNs. The measurements are compared with results from PSpice simulations and small discrepancies between the predictions and measurements are explained.

International Nuclear Information System (INIS)

Focused-ion beam (FIB) milling provides rapid fabrication of individual cylindrical submicrometer channels with reproducible dimensions (#+-#5% diameters) through 8-#mu#m thick poly(methylmethacrylate) (PMMA) films. PMMA films are spincast on sacrificial Si carriers and sputter-coated with Au before the 30-kV gallium FIB milling process. By adding a trace amount of poly(ethyleneoxide) and poly(dimethylsiloxane) to the PMMA solution before casting, the films can be released for subsequent mounting in microfluidic devices to create hybrid microfluidic-nanofluidic multilevel architectures. In situ FIB sectioning demonstrates the smooth cylindrical surface within the pore. Placing a milled film in contact with an aqueous fluorescein solution fills the channel by capillary action, as verified by confocal fluorescence microscopy. Confocal fluorescence of dyed films reveals that the pores span the thickness of the PMMA film. Small arrays of channels with a defined number ...

Energy Technology Data Exchange (ETDEWEB)

In order to enhance the resistance to the pitting corrosion due to asepsis processes and to avoid structural fractures in dentistry drills, a plasma immersion ion implantation (PIII) treatment using nitrogen has been performed. The selected drill samples, made of AISI 434 based stainless steel with a 0.670 mm diameter, were treated at a -1kV bias between 350 C and 450 C, this temperature being controlled by both a 20-50 {mu}s pulse width and a 200-1000 Hz repetition rate in the bias. The drills were analysed by cyclic potentiodynamic tests showing a good pitting corrosion resistance when treated at around 400 C, as follows from a resulting very low hysteresis loop. Yet, the resistance appears somehow diminished by the presence of sputtering when processed at temperatures near 450 C. It is also found that the PIII nitriding effectiveness appears to be limited by the appearance of uniform corrosion. Finally, X-ray diffraction of the samples has revealed the presence ...

Energy Technology Data Exchange (ETDEWEB)

This paper describes the criteria used for the thermal, electrical, mechanical, hydraulical design of the submarine power cables crossing Long Island Sound to feed New York City. The cables are of the self contained fluid filled (SCFF) type. There is also a description of the special measures adopted to face the exceptionally aggressive environment, due to presence of hydrogen sulphide and of stray currents (caused by electric railways and pipes cathodic protection). The most significant example of such measures is a third sacrificial armour. Four single-core SCFF cables (one spare) were manufactured in Arco Felice (near Naples, Italy), for the New York Power Authority. The average length of the cables is 13 km, jontless. The Italian cable ship 'Giulio Verne', managed by Pirelli, was utilized for the transportation and laying. The ship is equipped with a turntable of 7000 tonnes capacity. The cables are protected all along the route with a total embedment, from 1.5 to ...

International Nuclear Information System (INIS)

A method that employs simultaneous neutron and #gamma#-ray diffraction techniques is proposed for accurate measurements of strains with or without an applied electric field (0-100 kV m"-"1). Instead of an absolute determination of the position of the neutron Bragg peak, a relative measurement of the neutron and #gamma# peak positions is used and allows a determination of the lattice-parameter changes with an accuracy of within 2 x 10"-"6. This technique avoids systematic errors originating in sample rotations by taking advantage of a reference directly related to the crystal lattice. The method appears to be particularly important for crystals that exhibit structural phase transitions, as demonstrated by the measurement of the strain U_x_x in KH_2PO_4 crystals as a function of temperature and applied electric field. In this case the errors would amount to #+-#20%. The results demonstrate the need to re-examine the theory previously proposed by Uesu, Tanaka and ...

International Nuclear Information System (INIS)

The composition of sputter-deposited HgS films was determined by electron microprobe analysis. From the relative x-ray intensity as a function of film thickness, the depth of the ionizations that produce SK sub(#alpha#) and HgM sub(#alpha#) was found to be approximately 0.65 #mu#m at an accelerating voltage of 15 kV. This value agreed well with a value calculated from Castaings' empirical law after absorption correction. The determination of film composition was limited to sufficiently thicker films than this critical value, usually 1 - 2 #mu#m thick. The relation between the conposition of bulk standard determined by chemical analysis and the x-ray intensity ratio was used for the correction of film composition. The results showed that the crystal structure of HgS films was independent of the composition, i.e., the growth of metastable #betta#-HgS films was not caused by the nonstoichiometry, and that the composition of #alpha#-HgS films was not always ...

Energy Technology Data Exchange (ETDEWEB)

The Terra Nova offshore oil project is described, with emphasis on the construction of the Terra Nova Floating Production Storage and Offloading (FPSO) vessel, the first such vessel constructed for the harsh environment of the North Atlantic off Newfoundland, the site of an oil field that is expected to produce 125,000 to 150,000 barrels of oil per day starting in 2001. The vessel has a double-hull, made of 3,000 tons of reinforced steel to protect it from ice in the form of massive icebergs or crusty 'packs'. The vessel has the world's largest quick release turret, meaning that the vessel can be quickly disconnected from its turret and mooring in the event of an encroaching iceberg, and then reconnected in an environmentally sound way. Apart from its extremely rugged construction, protecting the FPSO vessel against icebergs is accomplished by way of 'hosing down' (by melting by powerful streams of water) or 'lassoing' (by ...

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This second report covers the period August 1 to September 30, 1991. During this period we modified our approach to Task 1 (Hybrid Armature study) with the addition of a numerical simulation of the steady state plasma brush length with a 1-D, four-phase equation of state code. A test fixture was designed and fabrication begun on a plasma brush test fixture for hybrid studies. It will be powered by a 140 kJ, 1 MA capacitor bank on loan to the project. Diagnostic data collection with 20 channels of digitizers and data reduction with a microvax were also arranged. Sliding friction of a solid armature was simulated and found to form a vapor layer at velocities below 2 km/s. The simulations indicated that higher interface pressure results in vapor boundary layer formation at lower velocity. If there is also a minimum interface pressure required to commutate high currents, then an optimum interface pressure will probably result. Plans for a launcher test bed were begun in preparation for ...

Energy Technology Data Exchange (ETDEWEB)

In this work tests of quality control in beams of X rays have been carried out, at diagnostic level, of two radiological services equipments of Brazilian hospitals (Aracaju, SE). We obtained the air kerma and kerma rate values, the beams efficiency, the coherence between the luminous fields and the referring fields of irradiation and half-value layer to each equipment and set of parameters. The measures of direct form have been obtained using two ionization chambers, one cylindrical and another one with parallel plates. An optional method for accomplishment some of the tests were carried out with CaSO{sub 4}:Dy + Teflon thermoluminescent dosimeters. The values of air kerma were evaluated for three tube voltage, 40, 60 and 81 kV at 1.0 m from the focus of the equipments. For each one of the voltages three distinct current values were chosen besides a fixed value of exposition time. The results showed that the values of air kerma varied between 8.0 {mu}Gy and 0.35 ...

International Nuclear Information System (INIS)

The first long pulse production of high power D"- ion beams has been demonstrated in the JT-60 U negative ion sources, each of which was designed to produce 22 A, 500 keV D"- ion beams. Voltage holding capability and the grid power loading were examined for long pulse production of high power D"- ion beams. From the correlation between voltage holding and the light intensity of cathodoluminescence from the Fiber Reinforced Plastic insulators, the acceleration voltage for stable voltage holding capability was found to be less than 320-340 kV where the light was sufficiently suppressed. By tuning the extraction voltage, the grid power loadings in the ion sources were decreased to the allowable levels for long pulse injection without a significant reduction of the beam power. After tuning the acceleration and extraction voltages, D"- ion beams of 12.5 and 9.8 A were produced at 340 keV with cesium seeding at a rate of #approx#14 #mu#g/s into the ion sources. The pulse ...

International Nuclear Information System (INIS)

The standard protocol in multislice spiral CT (MSCT) angiography for coronary arteries with fixed tube current-time settings leads to an overexposure and thus to an unnecessary high radiation dose in patients with lower weight when compared to heavier patients. The purpose of this study was to estimate the effect of reducing the radiation dose by adapting the tube current-time settings individually. Fifty patients underwent retrospectively ECG-gated MSCT of the heart. In 25 patients (group A_1) a standard protocol with constant tube current-time settings was used (4 x 1-mm collimation, 120 kV, 400 mAs_e_f_f). Subsequently, artificial image noise was added to the data of these patients simulating a directive for weight-adapted tube current-time settings (group A_2). In the other 25 patients (group B) an alternative protocol with individually weight-adapted tube current-time settings was applied. The data of all groups were evaluated by a regression analysis. The ...

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Populations living close to high-voltage transmission lines often have residential magnetic field exposures in excess of 1 [mu]T, and sometimes over 2 [mu]T. Yet, populations studied in most epidemiologic investigations of the association between residential magnetic field exposure and cancer typically have exposures below 1 [mu]T and frequently below 0.5 [mu]T. To improve statistical power and precision, it would be useful to compare high exposure populations with low exposure population. Toward this end, we have developed an automated method for identifying populations living near high-voltage transmissions lines. These populations likely have more highly exposed individuals that the population at large. The method uses a geographic information system (GIS) to superimpose digitized transmission line locations on U.S. Census block location data and then extract relevant demographic data. Analysis of data from a pilot study of the population residing within 100 m of a 29-km segment of ...

International Nuclear Information System (INIS)

The purpose of this work is to investigate the possible role of Helical CT defecography in pelvic floor disorders by comparing the results of the investigations with those of conventional defecography. The series analyzed consisted of 90 patients, namely 62 women and 28 men, ranging in age 24-82 years. They were all submitted to conventional defecography, and 18 questionable cases were also studied with Helical CT defecography. The conventional examination was performed during the 4 standard phases of resting, squeezing, Valsalva and straining; it is used a remote-control unit. The parameters for Helical CT defecography were: 5 mm beam collimation, pitch 2, 120 KV, 250 m As and 18-20 degrees gantry inclination to acquire coronal images of the pelvic floor. The rectal ampulla was distended with a bolus of 300 mL nonionic iodinated contrast agent (dilution: 3g/cc). The patient wore a napkin and was seated on the table, except for those who could not hold the position ...

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Computation of effective flow properties of fluids in porous media based on three dimensional (3D) pore structure information has become more successful in the last few years, due to both improvements in the input data and the network models. Computed X-ray microtomography has been successful in 3D pore imaging at micron scale, which is adequate for many sandstones. For other rocks of economic interest, such as chalk and diatomite, submicron resolution is needed in order to resolve the 3D-pore structure. To achieve submicron resolution, a new method of sample serial sectioning and imaging using Focused Ion Beam (FIB) technology has been developed and 3D pore images of the pore system for diatomite and chalk have been obtained. FIB was used in the milling of layers as wide as 50 micrometers and as thin as 100 nanometers by sputtering of atoms from the sample surface. The focused ion beam, consisting of gallium ions (Ga+) accelerated by potentials of up to 30 kV and ...

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Bone images obtained by single exposure dual energy subtraction with computed radiography, a new image processing method, were evaluated for the detectability of calcification in lung nodules in both phantom and clinical studies. In the phantom study, five simulated nodules containing known and uniformly distributed amounts of calcium hydroxide were placed in a human chest phantom and images were obtained the following five techniques: (1) conventional radiography (CXR), (2) low kV conventional radiography (Low), (3) Fuji computed radiography (FCR), (4) bone images with conventional singles exposure energy subtraction (ES) and (5) bone image with fine single exposure energy subtraction (FES). The detectability of calcification in the simulated nodules was evaluated by six radiologists using ROC analysis and two-way analysis of variance. In the clinical study, images of 42 lung nodules (21 calcified lung nodules and 21 non-calcified nodules), in which calcification ...

Energy Technology Data Exchange (ETDEWEB)

Four 10 MW, highly-stabilized power supply modules have been installed at the National High Magnetic Field Laboratory in Tallahassee, FL, to energize water-cooled, resistive, high-field research magnets. The power supply modules achieve a long term current stability if 10 ppM over a 12 h period with a short term ripple and noise variation of <10 ppM over a time period of one cycle. The power supply modules can operate independently, feeding four separate magnets, or two, three or four modules can operate in parallel. Each power supply module consists of a 12.5 kV vacuum circuit breaker, two three-winding, step-down transformers, a 24-pulse rectifier with interphase reactors, and a passive and an active filter. Two different transformer tap settings allow rated dc supply output voltages of 400 and 500 V. The rated current of a supply module is 17 kA and each supply module has a one-hour overload capability of 20 kA. The isolated output terminals of each power ...

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GaAs-based dc high voltage photoguns used at accelerators with extensive user programs must exhibit long photocathode operating lifetime. Achieving this goal represents a significant challenge for proposed high average current facilities that must operate at tens of milliamperes or more. This paper describes techniques to maintain good vacuum while delivering beam, and techniques that minimize the ill effects of ion bombardment, the dominant mechanism that reduces photocathode yield of a GaAs-based dc high voltage photogun. Experimental results presented here demonstrate enhanced lifetime at high beam currents by: (a) operating with the drive laser beam positioned away from the electrostatic center of the photocathode, (b) limiting the photocathode active area to eliminate photoemission from regions of the photocathode that do not support efficient beam delivery, (c) using a large drive laser beam to distribute ion damage over a larger area, and (d) by applying a relatively low bias ...

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The study of audible noise from high voltage transmission lines and a high voltage transformer station was conducted in three parts. Part 1 consisted of long-term measurement and statistical analysis by computer reduction of audible noise as a result of corona discharge from high voltage transmission lines and the associated weather conditions which contribute to this noise. Recommendations are given concerning further computer programming in order to improve the statistical reliability of corona noise presence and reduce the degree of background noise contamination of the present results. Part 2 consisted of categorizing and cataloguing of corona noise spectra from long-term measurements on 550, 735 and 765 kV transmission lines and to provide a library of such sounds on magnetic tape to be used in the ongoing study of corona noise. Twenty-five different corona sound spectra have been identified and documented in a tape library. Average weather conditions ...

International Nuclear Information System (INIS)

We have fabricated MgB_2 dc SQUIDs (superconducting quantum interference devices) containing inter-grain nanobridges as Josephson elements by a focused ion beam (FIB) etching method and measured their transport properties. The entire structure including the SQUID loop was patterned only using a FIB. The beam energy was 30 kV and the current was 0.9 nA for larger structures and 34 and 1.5 pA for the nanobridge pattern. Each bridge with a nominal width of 100 nm crossed a single grain boundary in the normal direction. The SQUID loop had a 3.1 #mu#m x 3.1 #mu#m hole with a 2 #mu#m average linewidth, corresponding to an inductance of 5.1 pH. The nanobridges had a two-step transition with an increase in the resistivity of more than a decade and a substantial decrease in the critical current density. Current-voltage characteristics showed a resistively shunted junction behavior at all temperatures below T_c, which implies that the current in the inter-grain nanobridges ...

International Nuclear Information System (INIS)

The results of experiments with a short period (9.6 mm) wiggler sheet electron beam (1.0 mm x 2.0 cm) millimeter-wave free electron laser (FEL) amplifier are presented. This FEL amplifier utilized a strong wiggler field for sheet beam confinement in the narrow beam dimension and an offset-pole side-focusing technique for the wide dimension beam confinement. The beam analysis herein includes finite emittance and space-charge effects. High-current beam propagation was achieved as a result of extensive analytical studies and experimental optimization. A design optimization resulted in a low sensitivity to structure errors and beam velocity spread, as well as a low required beam energy. A maximum gain of 24 dB was achieved with a 1-kW injected signal power at 86 GHz, a 450-kV beam voltage, 17-A beam current, 3.8-kG wiggler magnetic field, and a 74-period wiggler length. The maximum gain with a one-watt injected millimeter-wave power was observed to be over 30 dB. The ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this work is to investigate the possible role of Helical CT defecography in pelvic floor disorders by comparing the results of the investigations with those of conventional defecography. The series analyzed consisted of 90 patients, namely 62 women and 28 men, ranging in age 24-82 years. They were all submitted to conventional defecography, and 18 questionable cases were also studied with Helical CT defecography. The conventional examination was performed during the 4 standard phases of resting, squeezing, Valsalva and straining; it is used a remote-control unit. The parameters for Helical CT defecography were: 5 mm beam collimation, pitch 2, 120 KV, 250 m As and 18-20 degrees gantry inclination to acquire coronal images of the pelvic floor. The rectal ampulla was distended with a bolus of 300 mL nonionic iodinated contrast agent (dilution: 3g/cc). The patient wore a napkin and was seated on the table, except for those who could not hold the position ...

Energy Technology Data Exchange (ETDEWEB)

Laser spectroscopy measurements have been performed on neutron-deficient and stable Ir isotopes using the COMPLIS experimental setup installed at ISOLDE-CERN. The radioactive Ir atoms were obtained from successive decays of a mass-separated Hg beam deposited onto a carbon substrate after deceleration to 1kV and subsequently laser desorbed. A three-color, two-step resonant scheme was used to selectively ionize the desorbed Ir atoms. The hyperfine structure (HFS) and isotope shift (IS) of the first transition of the ionization path 5d{sup 7}6s{sup 24}F{sub 9/2}{yields}5d{sup 7}6s6p{sup 6}F{sub 11/2} at 351.5nm were measured for {sup 182-189}Ir, {sup 186}Ir{sup m} and the stable {sup 191,193}Ir. The nuclear magnetic moments {mu}{sub I} and the spectroscopic quadrupole moments Q{sub s} were obtained from the HFS spectra and the change of the mean square charge radii from the IS measurements. The sign of {mu}{sub I} was experimentally determined for the first time for ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study was to test a large sample of different coronary artery stents using four image reconstruction approaches with respect to lumen visualization, lumen attenuation, and image noise in 64-slice multidetector-row computed tomography (MDCT) in vitro and to provide a catalogue of currently used coronary artery stents when imaged with state-of the-art MDCT. We examined 68 different coronary artery stents (57 stainless steel, four cobalt-chromium, one cobalt-alloy, two nitinol, four tantalum) in a coronary artery phantom (vessel diameter 3 mm, intravascular attenuation 250 HU, extravascular density -70). Stents were imaged in axial orientation with standard parameters: 32x0.6 collimation, pitch 0.24, 680 mAs, 120 kV, rotation time 0.37 s. Four different image reconstructions were obtained with varying convolution kernels and section thicknesses: (1) soft, 0.6 mm, (2) soft, 0.75, (3) medium soft, 0.6, and (4) stent-optimized sharp, 0.6. To evaluate ...

Energy Technology Data Exchange (ETDEWEB)

TiO{sub 2} is a vital material in several technologies including, photocatalysis, gas sensing, biomaterials and optical coatings. Among the several crystal structures of this oxide, rutile has the highest density and microhardness, the highest index of refraction and the highest temperature stability. The processing of dense polycrystalline materials often includes the addition of a liquid-forming phase at higher temperatures. This technique is known as liquid-phase sintering and has been studied extensively. Rutile boundaries containing an amorphous phase have been used to study boundary migration and grain-boundary grooving. Visible-light (VLM), scanning electron (SEM) and transmission electron microscopy (TEM) in addition to electron-backscatter diffraction (EBSD) and a focused-ion beam (FIB) tool were used to characterize boundary migration in rutile. EBSD analysis was carried out on a Philips XL30 FEG SEM equipped with a DigiView 1612 high-resolution, high-speed CCD camera. A 2.5 ...