Ion acceleration by laser hole-boring into plasmas

International Nuclear Information System (INIS)

Pogorelsky, I. V.; Dover, N. P.; Babzien, M.; Bell, A. R.; Dangor, A. E.; Horbury, T.; Palmer, C. A. J.; Polyanskiy, M.; Schreiber, J.; Schwartz, S.; Shkolnikov, P.; Yakimenko, V.; Najmudin, Z.

2012-01-01

By experiment and simulations, we study the interaction of an intense CO 2 laser pulse with slightly overcritical plasmas of fully ionized helium gas. Transverse optical probing is used to show a recession of the front plasma surface with an initial velocity >10 6 m/s driven by hole-boring by the laser pulse and the resulting radiation pressure driven electrostatic shocks. The collisionless shock propagates through the plasma, dissipates into an ion-acoustic solitary wave, and eventually becomes collisional as it slows further. These observations are supported by PIC simulations which prove the conclusion that monoenergetic protons observed in our earlier reported experiment with a hydrogen jet result from ion trapping and reflection from a shock wave driven through the plasma.

Magnetic properties of the strongly correlated chain antiferromagnet KTb(WO4)2

International Nuclear Information System (INIS)

Khatsko, E.; Loginov, A.; Cherny, A.; Rykova, A.

2006-01-01

The susceptibility and magnetization of a single crystal of KTb(WO 4 ) 2 has been measured in the temperature range 0.5-80 K in magnetic fields up to 6 T. It is shown that KTb(WO 4 ) 2 is an Ising magnet with only one component of the magnetic moment. The three-dimensional phase transition to the antiferromagnetically ordered state has been found below 0.7 K. This transition can be described in the molecular field two-level approximation. The principal exchange constant has been estimated. By using experimental data the magnetic structure of KTb(WO 4 ) 2 is proposed

Prominent occurrence of iron oxides at KTB mass extinction: a review

African Journals Online (AJOL)

Out of the five major mass extinction, which have taken place in the history of life, Cretaceous–Tertiary boundary (KTB) mass extinction was the 2nd most disastrous, the most severe being that at Permian–Triassic boundary (PTB). On the basis of iridium anomaly at a number of KTB sites it has been established that the ...

Ultra-intense laser pulse propagation in plasmas: from classic hole-boring to incomplete hole-boring with relativistic transparency

International Nuclear Information System (INIS)

Weng, S M; Murakami, M; Mulser, P; Sheng, Z M

2012-01-01

Relativistic laser pulse propagation into homogeneous plasmas has been investigated as a function of plasma density. At first, the propagation features are compared systematically between relativistic transparency (RT) and hole-boring (HB). Paramountly, a considerably broad intermediate regime, namely the incomplete HB regime, has been found between the RT regime and the HB regime for an extremely intense circularly polarized (CP) pulse. In this regime HB proceeds in collaboration with RT, resulting in a much faster propagation speed and a higher cut-off energy of fast ions than in the classic HB regime. Similarly to the classic HB regime, formulae are presented to model the laser propagation and the ion acceleration according to the modified momentum flux balance in this incomplete HB regime. The simulations give the density boundary between this incomplete HB regime and the classic HB regime for CP pulses, which is crucial for estimating the maximum mean ion energy and the maximum conversion efficiency that can be achieved by the classic HB acceleration at a given laser intensity. For linear polarization (LP) the propagation mechanism apparently undergoes a transition in time between these two regimes. A detailed comparison between LP and circular polarization is made for these phenomena. (paper)

Dynamic study of a compressed electron layer during the hole-boring stage in a sharp-front laser interaction region

Directory of Open Access Journals (Sweden)

W. P. Wang

2012-08-01

Full Text Available This study investigates the dynamics of a compressed electron layer (CEL when a circularly polarized laser pulse with a sharp front irradiates a high-density foil. A time-dependent model for CEL motion during the hole-boring stage is proposed to describe details of the interaction for any shape of laser pulse. The opacity case, where the laser pulse is totally reflected, is investigated using this model. The results obtained are consistent with the results from particle-in-cell (PIC simulations. A relaxation distance determined by the laser-front steepness is necessary to build a stable CEL state before ions rejoin into the CEL. For the transparent case, the laser-front steepness is important for the formation of the stable CEL state at the back surface of the target. Considering the motion of ions, both the CEL and ion dynamics are important to rebalance the laser pressure and electrostatic charge-separation force as the hole-boring stage changes to the light-sail stage.

Filling bore-holes with explosive

Energy Technology Data Exchange (ETDEWEB)

Alfredsson, S H

1965-03-02

In this device for filling boreholes formed in a rock formation with particulate explosive, the explosive is conveyed into the hole by means of a pressure fluid through a tube which has a lesser diameter than the hole. The tube is characterized by a lattice work arranged externally on it, and having a structure adapted to allow passage of a pressure fluid returning between the tube and the wall of the hole, but retaining particles of explosive entrained by the returning pressure fluid. In another arrangement of the device, the lattice work has the form of a brush, including filaments or bristles which are dimensioned to bridge the spacing between the tube and the wall of the hole. (12 claims)

Analysis of Driven Pile Capacity within Pre-Bored Soil : Research Project Capsule

Science.gov (United States)

2017-10-01

Pre-boring is a method used to facilitate large displacement pile driving in hard/dense soils (see Figure 1). By pre-boring a pilot hole, the end bearing and side friction within the pre-bored zone are reduced, thus aiding pile driving installation. ...

Measurements of laser-hole boring into overdense plasmas using x-ray laser refractometry (invited)

International Nuclear Information System (INIS)

Kodama, R.; Takahashi, K.; Tanaka, K.A.; Kato, Y.; Murai, K.; Weber, F.; Barbee, T.W.; DaSilva, L.B.

1999-01-01

We developed a 19.6 nm laser x-ray laser grid-image refractometer (XRL-GIR) to diagnose laser-hole boring into overdense plasmas. The XRL-GIR was optimized to measure two-dimensional electron density perturbation on a scale of a few tens of μm in underdense plasmas. Electron density profiles of laser-produced plasmas were obtained for 10 20 - 10 22 cm -3 with the XRL-GIR and for 10 19 - 10 20 cm -3 from an ultraviolet interferometer, the profiles of which were compared with those from hydrodynamic simulation. By using this XRL-GIR, we directly observed laser channeling into overdense plasmas accompanied by a bow shock wave showing a Mach cone ascribed to supersonic propagation of the channel front. copyright 1999 American Institute of Physics

Key technologies of drilling process with raise boring method

Directory of Open Access Journals (Sweden)

Zhiqiang Liu

2015-08-01

Full Text Available This study presents the concept of shaft constructed by raise boring in underground mines, and the idea of inverse construction can be extended to other fields of underground engineering. The conventional raise boring methods, such as the wood support method, the hanging cage method, the creeping cage method, and the deep-hole blasting method, are analyzed and compared. In addition, the raise boring machines are classified into different types and the characteristics of each type are described. The components of a raise boring machine including the drill rig, the drill string and the auxiliary system are also presented. Based on the analysis of the raise boring method, the rock mechanics problems during the raise boring process are put forward, including rock fragmentation, removal of cuttings, shaft wall stability, and borehole deviation control. Finally, the development trends of raise boring technology are described as follows: (i improvement of rock-breaking modes to raise drilling efficiency, (ii development of an intelligent control technique, and (iii development of technology and equipment for nonlinear raise boring.

The assessment of bore-hole water quality of Kakamega County, Kenya

Science.gov (United States)

Christine, Adika A.; Kibet, Joshua K.; Kiprop, Ambsrose K.; Were, Munyendo L.

2018-03-01

Numerous deleterious impacts of anthropogenic activities on water quality are typically observed in areas bursting with mineral exploitation, agricultural activities, and industrial processes. Therefore, this contribution details the water quality and water origin in selected hand-dug wells of one the most prominent mining areas in Kenya (Kakamega County). The toxicological impacts of drinking water from a mining site may include cancer and genetic aberrations largely because of the toxic effects of waterborne metals including Hg and As. Accordingly, this study focuses primarily on the investigation of heavy metals, essential elements such as Na and K. Heavy metals and essential elements were determined using spectroscopic and titrimetric techniques. The study revealed that mercury (Hg) concentration ranged between 0.00256 and 0.0611 ± 0.00005 mg/L while arsenic (As) concentration ranged from 0.0103 to 0.0119 ± 0.00005 mg/L. The concentration of potassium ranged from 2.53 to 4.08 ± 0.15 mg/L while that of sodium varied from 6.74 to 9.260 ± 0.2 mg/L. Although the concentration of cadmium was lower than that recommended by W.H.O, the concentrations of Hg, Pb, and As in Kakamega waters were higher than the internationally accepted levels. The generally high level of heavy metals in Kakamega bore-hole waters is, therefore, a public health concern that needs immediate intervention.

THE EFFECT OF WELL-BORE REVERSE FLOW OF FLUID ON ...

African Journals Online (AJOL)

ES Obe

1980-03-01

Mar 1, 1980 ... ABSTRACT. Well-bore storage may dominate the bottom-hole pressure profile of ... Type- curve matching is however only accurate when the storage factor .... numerical integration technique ... existence of a measure of well-.

Improvement of the center boring device for the irradiated fuel pellets

Energy Technology Data Exchange (ETDEWEB)

Usami, Koji; Onozawa, Atsushi; Kimura, Yasuhiko; Sakuraba, Naotoshi; Shiina, Hidenori; Harada, Akito; Nakata, Masahito [Japan Atomic Energy Agency, Nuclear Science Research Inst., Tokai, Ibaraki (Japan)

2012-03-15

The power ramp tests performed at JMTR in Oarai R and D Center are objected to study the safety margin of the high burnup fuels. One of the important parameters measured during this test is the center temperature of the fuel pellet. For this measurement, a thermocouple is installed into the hole bored at the pellet center by the center boring device, which can fix the fuel pellet with the frozen CO{sub 2} gas during its boring process. At the Reactor Fuel Examination Facility (RFEF) in Tokai R and D Center, several improvements were applied for the previous boring device to gain its performance and reliability. The major improvements are the change of the drill bit, modification of the boring process and the optimization of the remote operability. The mock-up test will be performed with the irradiated fuel pellet to confirm the benefit of improvement. This study was conducted under a contract with the Nuclear and Industrial Safety Agency (NISA) of the Ministry of Economy, Trade and Industry (METI). (author)

Study on the detonation properties of explosives in bore hole and precise controlled blasting; Happa konai no bakuyaku no bakugosei to seimitsu seigyo happa ni kansuru kenkyu

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-10-08

In order to perform efficient and safe controlled blasting, attaining sufficient detonation from explosive is important. Therefore, a mechanism of detonation in a bore hole was studied. Two detonation phenomenon measuring methods were established: one is a continuous detonation speed measuring method by using a resistance wire probe, and another is a detonation mark observing and evaluating method using aluminum and metallic lead plates. Assuming delay blastings in multiple bore holes used practically, discussions were given on detonation phenomena of explosives under pressurized condition. Under dynamic pressure condition, size of the pressurization and delay time of the detonations affected largely the detonation. Discussions were given on blasting effect and safety according to difference in forward initiation and reverse initiation. The reverse initiation method was verified to have excellent blasting effect, maintain good face conditions, and assure safety against inflammable gases. A precision initiation method was developed, which can control the initiation time of a detonator more precisely. The initiation accuracy is more than 1000 times greater than the ordinary instantaneously detonating electric detonator. The precision control of the initiation time proved to develop greater crack propagation. Vibration and stone scattering were also controlled. This paper also describes application of the method to a rock elastic wave exploration technique. 136 refs., 99 figs., 13 tabs.

Recording and interpretation/analysis of tilt signals with five ASKANIA borehole tiltmeters at the KTB.

Science.gov (United States)

Gebauer, André; Jahr, Thomas; Jentzsch, Gerhard

2007-05-01

In June 2003, a large scale injection experiment started at the Continental Deep Drilling site (KTB) in Germany. A tiltmeter array was installed which consisted of five high resolution borehole tiltmeters of the ASKANIA type, also equipped with three dimensional seismometers. For the next 11 months, 86 000 m(3) were injected into the KTB pilot borehole 4000 m deep. The average injection rate was approximately 200 l/min. The research objective was to observe and to analyze deformation caused by the injection into the upper crust at the kilometer range. A new data acquisition system was developed by Geo-Research Center Potsdam (GFZ) to master the expected huge amount of seismic and tilt data. Furthermore, it was necessary to develop a new preprocessing software called PREANALYSE for long-period time series. This software includes different useful functions, such as step and spike correction, interpolation, filtering, and spectral analysis. This worldwide unique installation offers the excellent opportunity of the separation of signals due to injection and due to environment by correlation of the data of the five stations with the ground water table and meteorological data.

A magnetotelluric profile across the German Deep Drilling Project (KTB) area: Two- and three-dimensional modeling results

Czech Academy of Sciences Publication Activity Database

Eisel, M.; Haak, V.; Pek, Josef; Červ, Václav

2001-01-01

Roč. 106, B8 (2001), s. 16061-16073 ISSN 0148-0227 R&D Projects: GA ČR GA205/99/0917 Institutional research plan: CEZ:AV0Z3012916 Keywords : magnetotelluric profile * KTB * German Deep Drilling Project Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 2.609, year: 2001

Articles which include chevron film cooling holes, and related processes

Science.gov (United States)

Bunker, Ronald Scott; Lacy, Benjamin Paul

2014-12-09

An article is described, including an inner surface which can be exposed to a first fluid; an inlet; and an outer surface spaced from the inner surface, which can be exposed to a hotter second fluid. The article further includes at least one row or other pattern of passage holes. Each passage hole includes an inlet bore extending through the substrate from the inlet at the inner surface to a passage hole-exit proximate to the outer surface, with the inlet bore terminating in a chevron outlet adjacent the hole-exit. The chevron outlet includes a pair of wing troughs having a common surface region between them. The common surface region includes a valley which is adjacent the hole-exit; and a plateau adjacent the valley. The article can be an airfoil. Related methods for preparing the passage holes are also described.

Experimental investigation of hole boring and light sail regimes of RPA by varying laser and target parameters

International Nuclear Information System (INIS)

Kar, S; Kakolee, K F; Doria, D; Quinn, K; Ramakrishna, B; Sarri, G; Zepf, M; Borghesi, M; Cerchez, M; Osterholz, J; Willi, O; Macchi, A; McKenna, P; Yuan, X H; Neely, D

2013-01-01

Temporal evolution of plasma jets from micrometre-scale thick foils following the interaction of intense (3 × 10 20  W cm −2 ) laser pulses is studied systematically by time resolved optical interferometry. The fluid velocity in the plasma jets is determined by comparing the data with 2D hydrodynamic simulation, which agrees with the expected hole-boring (HB) velocity due to the laser radiation pressure. The homogeneity of the plasma density across the jets has been found to be improved substantially when irradiating the laser at circular polarization compared to linear polarization. While overdense plasma jets were formed efficiently for micrometre thick targets, decreasing the target areal density and/or increasing the irradiance on the target have provided indication of transition from the ‘HB’ to the ‘light sail (LS)’ regime of RPA, characterized by the appearance of narrow-band spectral features at several MeV/nucleon in proton and carbon spectra. (paper)

Dominance of hole-boring radiation pressure acceleration regime with thin ribbon of ionized solid hydrogen

Science.gov (United States)

Psikal, J.; Matys, M.

2018-04-01

Laser-driven proton acceleration from novel cryogenic hydrogen target of the thickness of tens of microns irradiated by multiPW laser pulse is investigated here for relevant laser parameters accessible in near future. It is demonstrated that the efficiency of proton acceleration from relatively thick hydrogen solid ribbon largely exceeds the acceleration efficiency for a thinner ionized plastic foil, which can be explained by enhanced hole boring (HB) driven by laser ponderomotive force in the case of light ions and lower target density. Three-dimensional particle-in-cell (PIC) simulations of laser pulse interaction with relatively thick hydrogen target show larger energies of protons accelerated in the target interior during the HB phase and reduced energies of protons accelerated from the rear side of the target by quasistatic electric field compared with the results obtained from two-dimensional PIC calculations. Linearly and circularly polarized multiPW laser pulses of duration exceeding 100 fs show similar performance in terms of proton acceleration from both the target interior as well as from the rear side of the target. When ultrashort pulse (∼30 fs) is assumed, the number of accelerated protons from the target interior is substantially reduced.

In-bore instrumentation/diagnostics for large-bore EMLs

International Nuclear Information System (INIS)

Fernandez, M.J.; Ager, S.A.; Hudson, R.D.

1991-01-01

This paper reports on a flying laboratory technique of in-bore diagnostics for large-bore electromagnetic launchers (EMLs). The high pressure, heat, and magnetic flux environment of the EML and its containment structures do not allow easy implementation of conventional diagnostic techniques. Researchers have relied on remote sensing methods, such as B probes (isolated from the bore), for data. The accuracy and relevance of such discrete, remote measurement is somewhat questionable. An in-house program has been initiated to determine the feasibility of making measurement of EML parameters on board a projectile. This technique utilizes off-the-shelf components in a configuration that has been proven effective in measuring projectile acceleration in the bore of propellant driven guns

Process for opening up carboniferous seams for underground gasification by drilling production holes downwards

Energy Technology Data Exchange (ETDEWEB)

Lokschin, J L; Volk, A F; Starinskii, A A

1977-12-01

This process will reduce drilling costs and times by 20 to 25% and will improve gasification under the influence of a thin liquid medium connecting adjacent holes. After determining the approximate depth and thickness of the seam to be opened up, e.g. by geological means, production holes of 100 to 400 mm (diameter) are made down to a depth of 400 m or more, by well-known boring bars and chisels. After passing the top of the seam (the roof of the seam), which can be recognised by discoloration of the drilling liquid, one goes 1/2 to 1 metre deeper and one determines the depth of the roof the seam exactly by the reduced natural radioactivity at the boundary layer, by introducing a gamma sensor on to the boring bar. The production holes are taken down in a second borehold to a free space 0.6 to 2 metres above the floor of the seam (bottom of the seam), according to the thickness of the seam. After replacing the boring bar by a feedpipe one continues to drill using a boring bar of smaller cutting diameter inside this tube. This hole reaches from the foot of the pipe of the feedpipe to the floor of the seam. It is preferably flushed with gas but may be flushed with liquid. A thin liquid introduced into this hole penetrates the surrounding mass of the seam horizontally (unhindered by any armouring) and represents the required connection to neighbouring bores for gasification. The process is suitable for mining coal, combustible shale oil, bituminous rock, heavy natural oil where this process is based on gasification, melting or dissolving of those deposits.

Microstructure, Morphology, and Nanomechanical Properties Near Fine Holes Produced by Electro-Discharge Machining

Science.gov (United States)

Blau, P. J.; Howe, J. Y.; Coffey, D. W.; Trejo, R. M.; Kenik, E. D.; Jolly, B. C.; Yang, N.

2012-08-01

Fine holes in metal alloys are employed for many important technological purposes, including cooling and the precise atomization of liquids. For example, they play an important role in the metering and delivery of fuel to the combustion chambers in energy-efficient, low-emission diesel engines. Electro-discharge machining (EDM) is one process employed to produce such holes. Since the hole shape and bore morphology can affect fluid flow, and holes also represent structural discontinuities in the tips of the spray nozzles, it is important to understand the microstructures adjacent to these holes, the features of the hole walls, and the nanomechanical properties of the material that was in some manner altered by the EDM hole-making process. Several techniques were used to characterize the structure and properties of spray-holes in a commercial injector nozzle. These include scanning electron microscopy, cross sectioning and metallographic etching, bore surface roughness measurements by optical interferometry, scanning electron microscopy, and transmission electron microscopy of recast EDM layers extracted with the help of a focused ion beam.

Tunnel boring an alternative method in construction of spent fuel repositories

International Nuclear Information System (INIS)

Christersson, Jukka

1984-05-01

In projecting of the final disposal of nuclear waste in geological formations a great importance should be paid to the selection of the tunneling method. The environment of the chosen repository area should not be exposed to any but as minor disturbances as possible by the excavation method applied. This study approaches full face tunneling methods as an alternative to conventional drill-and-blast methods in the construction of spent fuel repository tunnels. According to experiences up till now it is obvious, that tunnelboring today is fully capable technically competing with conventional tunneling methods, even in the hardest granitic rocks. The most important advantages, it provides for the construction of repositories, are: The methods does not produce any damage in the surrounding rock. Possibility to use placement techniques, which do not require preparing of additive repository holes for the fuel elements. Saving in the use of expensive filling material. The fact, that tunnel boring in hard rock is an expensive alternative, is still valid. Constuction of straight lined tunnels in unfractured rocks by tunnel boring would cost about 30-40% more than by conventional methods. The lay out arrangement of bored tunnels still have a great influence on tunnel boring machine's economy. Due to this it would be round 40-70% more expensive method in the construction of spent fuel repositories. However intensive development w is being carried out to eliminate these limitations and to make machines more flexible. Future trends in tunnel boring look good at the moment. The number of sold units has been increasing and new applications have widen out during last ten years. Harder and more abrasive rocks can now be bored than ever before and the trend seems to continue. It also looks like the cost difference in the hardest rocks is firmly getting smaller and smaller all the time. (author)

Fiscal 1982 Sunshine Project research report. Development of bore hole measurement technology; 1982 nendo koseinai sokutei gijutsu no kaihatsu seika hokokusho

Energy Technology Data Exchange (ETDEWEB)

NONE

1983-03-01

This report summarizes the fiscal 1982 research result on development of measuring instruments for information collection in geothermal bore holes under high-temperature high-pressure conditions. In development of high-temperature well logging cable, the new TFE Teflon insulated well logging cable (3,300m) applicable up to 320 degreesC was prepared. In development of digital well logging system, the data analyzer for edition and analysis of recorded digital logging data, the depth panel with an automatic depth correction mechanism, and the fiber optics controller were prepared. Preparation of the whole digital well logging system was thus completed. Field test was made at 3 wells in 2 geothermal areas. At the test well in Nigori-Gawa area, Hokkaido, performance test was made on the digital well logging system, TFE Teflon well logging cable, and improved winch completed in this fiscal year. At the same time, the radioactive well logging test using radioactive isotope showed the satisfactory result except neutron well logging. (NEDO)

Ferroacryl mud for drilling deep bore holes

Energy Technology Data Exchange (ETDEWEB)

Lisyanskiy, V I; Chepiga, V I; Devydenko, V N

1982-01-01

The composition, technology of production and control of the parameters of a ferroacyl (FAR) mud for drilling for prospecting holes in the Donets-Basin are developed. The mud consists of Chasov Yal clay (150-160 kg), hypane (40 1), iron sulfate (1kg) and water (approximately 1 m/sup 3/). The mud exhibits the following parameters: density 1.05 -1.1 g/cm/sup 3/, viscosity 20-21 s; water yield 3-5 cm/sup 3/; crust 0.5 mm. Compared to existing flushing fluids based on hypane the FAR contains fewer components and the cost of the materials is considerably less. It features very high flocculating properties.

A Computer-Controlled Laser Bore Scanner

Science.gov (United States)

Cheng, Charles C.

1980-08-01

This paper describes the design and engineering of a laser scanning system for production applications. The laser scanning techniques, the timing control, the logic design of the pattern recognition subsystem, the digital computer servo control for the loading and un-loading of parts, and the laser probe rotation and its synchronization will be discussed. The laser inspection machine is designed to automatically inspect the surface of precision-bored holes, such as those in automobile master cylinders, without contacting the machined surface. Although the controls are relatively sophisticated, operation of the laser inspection machine is simple. A laser light beam from a commercially available gas laser, directed through a probe, scans the entire surface of the bore. Reflected light, picked up through optics by photoelectric sensors, generates signals that are fed to a mini-computer for processing. A pattern recognition techniques program in the computer determines acceptance or rejection of the part being inspected. The system's acceptance specifications are adjustable and are set to the user's established tolerances. However, the computer-controlled laser system is capable of defining from 10 to 75 rms surface finish, and voids or flaws from 0.0005 to 0.020 inch. Following the successful demonstration with an engineering prototype, the described laser machine has proved its capability to consistently ensure high-quality master brake cylinders. It thus provides a safety improvement for the automotive braking system. Flawless, smooth cylinder bores eliminate premature wearing of the rubber seals, resulting in a longer-lasting master brake cylinder and a safer and more reliable automobile. The results obtained from use of this system, which has been in operation about a year for replacement of a tedious, manual operation on one of the high-volume lines at the Bendix Hydraulics Division, have been very satisfactory.

A boring solution

Energy Technology Data Exchange (ETDEWEB)

Radiuk, M I; Iushkova, N E; Kozubovskii, A I

1979-10-25

A boring solution is being patented for boring for oil and gas, which can be used in wells, where the temperature of the circulating liquid reaches 100/sup 0/. Polyvinyl acetate emulsion (PVE) is added for the purpose of decreasing viscosity of the solution at a temperature of agression into the boring solution containing clay, water, carboxymethylcellulose (CBC), a chloride from the number of sodium, potassium, or magnesium chlorides. The solution has the following composition in %: clay, 10 to 20; CBC, 1.5 to 2.0; chloride, 5 to 20; PVE, 0.5 to 2; water, up to 100. In accordance to GOST 1000-62 for the accepted PVE, the compound has the following composition, in %: monomer, 0.8; dry residue, greater than or equal to 50; plasticizer (tributyl phthalate), 5 to 15. The boring solution is processed according to the following method. The original solution, containing clay, water, salts, receives 1.5 to 2% CBC and afterwards it is processed with 0.5 to 2% PVE.

Drilling miniature holes, Part III

Energy Technology Data Exchange (ETDEWEB)

Gillespie, L.K.

1978-07-01

Miniature components for precision electromechanical mechanisms such as switches, timers, and actuators typically require a number of small holes. Because of the precision required, the workpiece materials, and the geometry of the parts, most of these holes must be produced by conventional drilling techniques. The use of such techniques is tedious and often requires considerable trial and error to prevent drill breakage, minimize hole mislocation and variations in hole diameter. This study of eight commercial drill designs revealed that printed circuit board drills produced better locational and size repeatability than did other drills when centerdrilling was not used. Boring holes 1 mm in dia, or less, as a general rule did not improve hole location in brass or stainless steel. Hole locations of patterns of 0.66-mm holes can be maintained within 25.4-..mu..m diametral positional tolerance if setup misalignments can be eliminated. Size tolerances of +- 3.8 ..mu..m can be maintained under some conditions when drilling flat plates. While these levels of precision are possible with existing off-the-shelf drills, they may not be practical in many cases.

Subsurface deposition of Cu-rich massive sulphide underneath a Palaeoproterozoic seafloor hydrothermal system—the Red Bore prospect, Western Australia

Science.gov (United States)

Agangi, Andrea; Reddy, S. M.; Plavsa, D.; Vieru, C.; Selvaraja, V.; LaFlamme, C.; Jeon, H.; Martin, L.; Nozaki, T.; Takaya, Y.; Suzuki, K.

2018-02-01

The Proterozoic Bryah and Yerrida basins of Western Australia contain important base and precious metal deposits. Here we present microtextural data, trace element and S isotope analyses of massive sulphide mineralisation hosted in Palaeoproterozoic subvolcanic rocks (dolerite) recently discovered at Red Bore. The small-scale high-grade mineralisation, which extends from the sub-surface to at least 95 m down-hole, is dominated by massive chalcopyrite and contains minor pyrite and Bi-Te-(Se) phases. Massive sulphide mineralisation is surrounded by discontinuous brecciated massive magnetite, and a narrow (data are permissive of a genetic association of Red Bore mineralisation with VHMS deposits nearby, thus suggesting a direct connection between magmatism and mineralising fluids responsible for VHMS deposition at surface. Therefore, the Red Bore mineralisation may represent the magmatic roots of a VHMS system.

Geothermal modelling of faulted metamorphic crystalline crust: a new model of the Continental Deep Drilling Site KTB (Germany)

Science.gov (United States)

Szalaiová, Eva; Rabbel, Wolfgang; Marquart, Gabriele; Vogt, Christian

2015-11-01

The area of the 9.1-km-deep Continental Deep Drillhole (KTB) in Germany is used as a case study for a geothermal reservoir situated in folded and faulted metamorphic crystalline crust. The presented approach is based on the analysis of 3-D seismic reflection data combined with borehole data and hydrothermal numerical modelling. The KTB location exemplarily contains all elements that make seismic prospecting in crystalline environment often more difficult than in sedimentary units, basically complicated tectonics and fracturing and low-coherent strata. In a first step major rock units including two known nearly parallel fault zones are identified down to a depth of 12 km. These units form the basis of a gridded 3-D numerical model for investigating temperature and fluid flow. Conductive and advective heat transport takes place mainly in a metamorphic block composed of gneisses and metabasites that show considerable differences in thermal conductivity and heat production. Therefore, in a second step, the structure of this unit is investigated by seismic waveform modelling. The third step of interpretation consists of applying wavenumber filtering and log-Gabor-filtering for locating fractures. Since fracture networks are the major fluid pathways in the crystalline, we associate the fracture density distribution with distributions of relative porosity and permeability that can be calibrated by logging data and forward modelling of the temperature field. The resulting permeability distribution shows values between 10-16 and 10-19 m2 and does not correlate with particular rock units. Once thermohydraulic rock properties are attributed to the numerical model, the differential equations for heat and fluid transport in porous media are solved numerically based on a finite difference approach. The hydraulic potential caused by topography and a heat flux of 54 mW m-2 were applied as boundary conditions at the top and bottom of the model. Fluid flow is generally slow and

Imaging the Variscan suture at the KTB deep drilling site, Germany

Science.gov (United States)

Bianchi, Irene; Bokelmann, Götz

2018-06-01

The upper crust of the KTB (Kontinentales Tiefbohrprogramm) area in the Southeastern Germany is a focal point for the Earth Science community due to the huge amount of information collected throughout the last 30 yr. In this study, we explore the crustal structure of the KTB area through the application of the Receiver Function (RF) technique to a new data set recorded by nine temporary seismic stations and one permanent station. We aim to unravel the isotropic structure and compare our results with previous information from the reflection profiles collected during the initial site investigations. Due to the large amount of information collected by previous studies, in terms of P-wave velocity, depth and location of major reflectors, depth reconstruction of major faults zones, this area represents a unique occasion to test the resolution capability of a passive seismological study performed by the application of the RF. We aim to verify which contribution could be given by the application of the RF technique, for future studies, in order to get clear images of the deep structure and up to which resolution. The RF technique has apparently not been applied in the area before, yet it may give useful additional insight in subsurface structure, particularly at depths larger than the maximum depth reached by drilling, but also on structures in the upper crust, around the area that has been studied in detail previously. In our results vS-depth profiles for stations located on the same geological units display common features and show shallow S-wave velocities typical of the outcropping geological units (i.e. sedimentary basin, granites and metamorphic rocks). At around 10 km depth, we observe a strong velocity increase beneath all stations. For the stations located in the centre of the area, this variation is weaker, which we assume to be the signature of the main tectonic suture in the area (i.e. the Saxothuringian-Moldanubian suture), along a west-to-east extended

Atmospheric noise of a breaking tidal bore.

Science.gov (United States)

Chanson, Hubert

2016-01-01

A tidal bore is a surge of waters propagating upstream in an estuary as the tidal flow turns to rising and the flood tide propagates into a funnel-shaped system. Large tidal bores have a marked breaking roller. The sounds generated by breaking tidal bores were herein investigated in the field (Qiantang River) and in laboratory. The sound pressure record showed two dominant periods, with some similarity with an earlier study [Chanson (2009). J. Acoust. Soc. Am. 125(6), 3561-3568]. The two distinct phases were the incoming tidal bore when the sound amplitude increased with the approaching bore, and the passage of the tidal bore in front of the microphone when loud and powerful noises were heard. The dominant frequency ranged from 57 to 131 Hz in the Qiantang River bore. A comparison between laboratory and prototype tidal bores illustrated both common features and differences. The low pitch sound of the breaking bore had a dominant frequency close to the collective oscillations of bubble clouds, which could be modeled with a bubble cloud model using a transverse dimension of the bore roller. The findings suggest that this model might be over simplistic in the case of a powerful breaking bore, like that of the Qiantang River.

Pulverization of boron element and proportions of boron carbide in boron; Broyage de bore element et dosage de carbure de bore dans le bore

Energy Technology Data Exchange (ETDEWEB)

Lang, F M; Finck, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1956-07-01

It is possible to reduce boron element into fine powder by means of a mortar and pestle made of sintered boron carbide, the ratio of boron carbide introduced being less than one per cent. Boron element at our disposal is made of sharp edged, dark brown, little grains of average size greater than 5 {mu}. Grain sizes smaller than 1{mu} are required for applying thin layers of such boron. (author) [French] Il est possible de pulveriser finement du bore element au moyen de mortier et pilon en carbure de bore fritte, le taux de carbure de bore introduit etant inferieur a 1 pour cent. Le bore element dont nous disposons est constitue de petits grains brun fonce, a aretes vives, de dimension moyenne superieure a 5 {mu}. L'application de ce bore en couches minces demande des grains de dimensions inferieures a 1 {mu}. (aute0008.

Eddy current and quench loads and stress of SSC collider 4-K liner and the bore tube during magnet quench

International Nuclear Information System (INIS)

Leung, K.K.; Shu, Q.S.

1993-07-01

This paper describes the response of the eddy current and quench loads on a proposed Superconducting SuperCollider 4-K liner system. The liner within a bore tube is designed to remove the radiated power and the photodesorbed gas that impair the beam tube vacuum. The bimetallic liner tube is subjected to cooldown and eddy current loads. The square liner tube is a two-shell laminated Nitronic-40 steel is used for strength and a copper inner layer for low impedance to the image currents. Perforated holes are used to remove the photodesorbed gases for vacuum maintenance. The holes are located in a low-stress area of the liner. Rectangular holes in a four-pole symmetry pattern are required for beam dynamic stability. The liner is conductivity cooled by the round steel bore tube with a 2-mm wall. The copper layer must not be stressed over the yield strength limit because copper properties such as conductivity are known to change when the copper is stressed over yield strength. This analysis will address liner system response under thermal, eddy current, and vaporized liquid helium loads in a quenching dipole magnet

Drilling holes in rock for final storage of spent nuclear fuel

International Nuclear Information System (INIS)

Nord, G.

1980-09-01

This report delas with the technical and economic aspects of the drilling of vertical holes with diameters of 1.5 metres and 1 metre in the Swedish bedrock. The holes will be 7.7 metres in depth and located on a level approximately 500 metres below the ground surface. There is no directly applicable technique for the construction of the above-mentioned holes from a small tunnel. The data presented in this report are based to a great extent on information supplied by the manufacturers of drilling equipment, and by underground construction contractors. Three different techniques for drilling the holes have been delat with in the report: shaft boring, stitch drilling (three alternative methods) and core drilling. In order to produce the required 233 holes per year, the following sets of equipment must be purchased, and personnel engaged. A hole with a diameter of 1.5 m and a depth of 7.7 m requires 3 to 7 sets of equipment for shaft boring or stitch drilling and engages 12 to 27 employees. The cost per hole varies between 24.200 and 31.200 SKr. Core drilling requires 7 sets of equipment, engages 29 persons and costs 55.300 SKr per hole. A hole with a diameter of 1.0 m requires less personnel and costs between 19.700 and 25.800 per hole except for core drilling where the cost per hole is estimated to 43.900 SKr. Interest costs account for 10 percent - 15 percent of the above-mentioned costs. Our aim has been to calculate the costs for the different methods on as similar a basis as possible, but a margin of error of +- 15 percent entails and overlapping of the cost span for most of the methods considered. (G.B.)

Electric signal emissions during repeated abrupt uniaxial compressional stress steps in amphibolite from KTB drilling

Directory of Open Access Journals (Sweden)

D. Triantis

2007-01-01

Full Text Available Laboratory experiments have confirmed that the application of uniaxial stress on rock samples is accompanied by the production of weak electric currents, to which the term Pressure Stimulated Currents – PSC has been attributed. In this work the PSC emissions in amphibolite samples from KTB drilling are presented and commented upon. After having applied sequential loading and unloading cycles on the amphibolite samples, it was ascertained that in every new loading cycle after unloading, the emitted PSC exhibits lower peaks. This attitude of the current peaks is consistent with the acoustic emissions phenomena, and in this work is verified for PSC emissions during loading – unloading procedures. Consequently, the evaluation of such signals can help to correlate the state and the remaining strength of the sample with respect to the history of its mechanical stress.

Effects of slim holes on hydrothermal exploration costs

International Nuclear Information System (INIS)

Entingh, D.; Petty, S.

1992-01-01

This paper estimates hydrothermal exploration costs and the effects that using slim holes could have on those costs using a computer code developed for the US-DOE. The primary goal of exploration is to generate decision driving information about particular geothermal reservoirs. Compared to today's exploration strategies, the main effect of using slim holes would be to reduce the cost of exploration by about 40 percent. Slim hole exploration does not reduce the overall cost of electricity by much; however, the cost burden is shifted later in the project when outside financing is more likely. The reduced costs of slim holes may also encourage developers to drill more holes that better characterize the reservoir, thus reducing long term reservoir risk. The cost of power could then be cut as much as six percent and project financial risks related to reservoir uncertainties could be reduced by up to one quarter. In order to realize these improvements, the amount of reservoir information recovered from small diameter bore holes needs to be significantly increased

Mechanisms for closing bores and releasably securing articles within the bores under longitudinal load

International Nuclear Information System (INIS)

Klahn, F.C.; Nolan, J.H.; Wills, C.

1979-01-01

This invention relates to mechanisms for closing bores of tubular passages and for releasably securing articles within the bores under longitudinal load. The system includes an axially movable latch, an actuator and locking devices. Embodiments of the invention can be used as closure mechanisms for tubular irradiation surveillance specimen assembly holders used in nuclear reactors. (UK)

Mechanisms for closing bores and releasably securing articles within the bores under longitudinal load

International Nuclear Information System (INIS)

Kalen, D.D.; Mitchem, J.W.

1979-01-01

This invention relates to mechanisms for closing bores of tubular passages and for releasably securing articles within the bores under longitudinal load. The system includes an axially movable actuator and a latch which engages the tubular opening. Embodiments of the invention can be used as closure mechanisms for tubular irradiation surveillance specimen assembly holders used in nuclear reactors. (UK)

Large-diameter boring of rock bed by a reveres circulation drill; Ribasu sakyureshon doriru ni yoru daikokei ganban sakko

Energy Technology Data Exchange (ETDEWEB)

Sakae, S.; Torii, K. [Kajima Corp., Tokyo (Japan); Hoshino, S.; Motoyama, M.

1995-09-25

The Itojima Large Bridge is a road bridge of 675 m in the total length connecting together the Nagashima Island and the Itojima Island in the northwest district of Kagoshima Prefecture, having a central span of 260 m and comprising a 5-span-continuous PC cable stayed bridges and PC box girder bridges. The foundation of this bridge employs a multi-pillar type pile structure. The piling work was started in July, 1991 by a hole inset method in a severe working environment where the depth of water is 20 m, the range of the tides is 4 m, the speed of tidal current is 2 kt, the rock bed structure is complicated and the steep seabed is steeply inclined. This report describes the results of the execution of the reverse circulation drilling, which has a high general versatility in rock bed boring, using self-lifting barges and large working boats during the rock bed boring for the foundation piling for the construction of the Itojima Large Bridge. The report, especially, also introduces the details of the work that casing pipes were driven into a stable rock bed by a vibrojet method for the measure against the collapse of a bore wall which occurred during the boring work. 24 figs., 14 tabs.

Energy Efficiency of Tunnel Boring Machines.

OpenAIRE

Grishenko, Vitaly

2014-01-01

Herrenknecht AG is a German world-leading Tunnel Boring Machines manufacturer showing strong awareness and concern regarding environmental issues. The company supports research on the Energy Efficiency (EE) of their products, aimed at the development of intelligent design for a green Tunnel Boring Machine. The aim of this project is to produce a ’status quo’ report on EE of three types of Tunnel Boring Machines (Hardrock, EPB and Mixshield TBM). In the framework of this research 39 projects a...

Conditions for tidal bore formation in convergent alluvial estuaries

Science.gov (United States)

Bonneton, Philippe; Filippini, Andrea Gilberto; Arpaia, Luca; Bonneton, Natalie; Ricchiuto, Mario

2016-04-01

Over the last decade there has been an increasing interest in tidal bore dynamics. However most studies have been focused on small-scale bore processes. The present paper describes the first quantitative study, at the estuary scale, of the conditions for tidal bore formation in convergent alluvial estuaries. When freshwater discharge and large-scale spatial variations of the estuary water depth can be neglected, tide propagation in such estuaries is controlled by three main dimensionless parameters: the nonlinearity parameter ε0 , the convergence ratio δ0 and the friction parameter ϕ0. In this paper we explore this dimensionless parameter space, in terms of tidal bore occurrence, from a database of 21 estuaries (8 tidal-bore estuaries and 13 non tidal-bore estuaries). The field data point out that tidal bores occur for convergence ratios close to the critical convergence δc. A new proposed definition of the friction parameter highlights a clear separation on the parameter plane (ϕ0,ε0) between tidal-bore estuaries and non tidal-bore estuaries. More specifically, we have established that tidal bores occur in convergent estuaries when the nonlinearity parameter is greater than a critical value, εc , which is an increasing function of the friction parameter ϕ0. This result has been confirmed by numerical simulations of the two-dimensional Saint Venant equations. The real-estuary observations and the numerical simulations also show that, contrary to what is generally assumed, tide amplification is not a necessary condition for tidal bore formation. The effect of freshwater discharge on tidal bore occurrence has been analyzed from the database acquired during three long-term campaigns carried out on the Gironde/Garonne estuary. We have shown that in the upper estuary the tidal bore intensity is mainly governed by the local dimensionless tide amplitude ε. The bore intensity is an increasing function of ε and this relationship does not depend on freshwater

NNWSI [Nevada Nuclear Waste Storage Investigations] hole histories: UE-29a No. 1, UE-29a No. 2

International Nuclear Information System (INIS)

1986-11-01

This report is a compilation of data from two hydrologic exploratory core holes drilled to help identify the area geology and hydrology. The two bore holes were drilled between September, 1981 and January, 1982 under the guidance of the US Geological Survey in Area 29, Nevada Test Site. Data presented in the hole histories include all locations, daily activities, coring records, review of hole conditions, and geophysical log lists, and microfiche copies of the geophysical logs run by the Fenix and Scisson, Inc. subcontractor

Test with different stress measurement methods in two orthogonal bore holes in Aespoe HRL

Energy Technology Data Exchange (ETDEWEB)

Janson, Thomas; Stigsson, Martin [Golder Associates AB, Stockholm (Sweden)

2002-12-01

conclusions have been drawn, based on the stress measurements and deeper investigations: The following stress state is obtained at the target volume at about -455 m. The minimum horizontal stress is between 10 and 13 MPa, which is lower than the theoretical vertical stress. The maximum horizontal stress is 24 {+-}5 MPa, most likely within the upper range. The vertical stress is between 15 and 20 MPa, most probably is this value only local due to the presence of a nearby fracture. The local disturbance of the stress field in the rock mass, due to discontinuities has been demonstrated. This also indicates one of the problems with stress measurements in boreholes. In the area with significant anisotropic stress conditions all the tested methods were able to determine the orientation of the principal major horizontal stress within {+-} 10 deg. The microscopy investigations confirm two sets of microcracks in the overcored core. One set was parallel and near the bore hole bottom and one set was perpendicular to the bottom and located a bit away from the hole bottom. The results from the overcoring may be influenced by microcracks, causing additional non-elastic strains. Only the results from the DDGS seem to have been influenced, indicating that the hollow cylinder of a 3D stress cell may be less sensitive for stress induced sample disturbance than core samples from the 2D Door stopper cell. The determination of Young's modulus in a medium grained crystalline rock with heterogeneity may not be trivial using core samples. The results from the determination influence the calculated stresses. Hydraulic fracturing most likely measures the most correct value of the minimum horizontal stress, provided that the induced fracture is aligned with the borehole. If the rock behaves reasonable elastic the overcoring methods provide stress magnitudes with an uncertainty of 15-20%. It seems likely that the overcoring methods may overestimate the stress magnitudes at large depth, due to the

TMI-2 core bore acquisition summary report

International Nuclear Information System (INIS)

Tolman, E.L.; Smith, R.P.; Martin, M.R.; McCardell, R.K.; Broughton, J.M.

1986-09-01

Core bore samples were obtained from the severely damaged TMI-2 core during July and August, 1986. A description of the TMI-2 core bore drilling unit used to obtain samples; a summary and discussion of the data from the ten core bore segments which were obtained; and the initial results of analysis and evaluation of these data are presented in this report. The impact of the major findings relative to our understanding of the accident scenario is also discussed

Development of a Laser-Guided Deep-Hole Internal-Grinding Tool (Series 1) : Grinding Forces

OpenAIRE

Katsuki, Akio; Onikura, Hiromichi; Sajima, Takao; Park, Hyunkoo

2005-01-01

The laser-guided deep-hole internal grinding tool is developed to bore accurate and straight deep-holes with high surface quality. The tool consists of a grinding head, the front and rear actuators mounted on an actuator holder and a laser diode set in the back end of the holder. The grinding head consists of a diamond or CBN wheel, an air motor, and the piezoelectric actuators for the compensation of tool diameter. The grinding wheel is located eccentrically at the grinding head. The grindin...

Turbulent mixing and wave radiation in non-Boussinesq internal bores

DEFF Research Database (Denmark)

Borden, Zac; Koblitz, Tilman; Meiburg, Eckart

2012-01-01

Bores, or hydraulic jumps, appear in many natural settings and are useful in many industrial applications. If the densities of the two fluids between which a bore propagates are very different (i.e., water and air), the less dense fluid can be neglected when modeling a bore analytically-a single...... ratio, defined as the ratio of the density of the lighter fluid to the heavier fluid, is greater than approximately one half. For smaller density ratios, undular waves generated at the bore's front dominate over the effects of turbulent mixing, and the expanding layer loses energy across the bore. Based...

Removing well bore liquid blockage by gas injection

International Nuclear Information System (INIS)

Ahmed, Tarek

2000-01-01

Gas condensate reservoirs have long presented production problems when the pressure around the well bore drops below the dew point pressure. The formation of the condensate around the well bore can be thought of as an additional 'skin' that causes a reduction in the gas flow rates. Many processes have been used successfully to prevent or reduce the formation of liquids within the entire reservoir, such as pressure maintenance schemes and gas cycling processes. The pressure maintenance scheme is designed to keep the reservoir pressure at or above the dew point pressure while the gas cycling process is intended to reduce the liquid dropout by vaporization.Often times the pressure in the near-well bore region of the reservoir falls below the dew point pressure, while the pressure in the reservoir remains higher than the dew point pressure. As the near-well bore pressure drops below the dew point pressure, retrograde condensation occurs leading to the formation and then the mobilization of the condensate phase towards the producing wells. The liquid phase accumulates in the near Well bore region, forming a ring, which progressively reduces the gas deliverability. This study is designed to provide an insight into the mechanism of gas injection process in reducing gas-well productivity losses due to condensate blocking in the near well bore region. The study also evaluates the effectiveness of lean gas, N 2 , and CO 2 Huff 'n' Puff injection technique in removing the liquid dropout accumulation in and around the well bore. Results of the study show the importance of selecting the optimum injection volume and pressure. (author)

Natural Pu-traces within the continental crust

International Nuclear Information System (INIS)

Ganz, M.; Barth, H.; Fuest, M.; Molzahn, D.; Brandt, R.

1991-01-01

Pu-traces are observed in the environmental all over the world, 'man made'-Pu as well as 'natural' Pu ( 239 Pu). 239 Pu occurs within a range of about 10 -12 g Pu/g sample in pitchblende. In the FRG, the deep-drilling project 'KTB, Kontinentales Tiefbohrprogramm', was started with the aim to obtain a very deep hole (14 km). We wanted to establish upper concentration limits for plutonium in samples from KTB. For a first investigation, we obtained a 400 g sample of granite from a pre-drill of KTB. Its Pu-concentration was ≤ (4.5 ± 2.5)x10 -16 g 239 Pu/g sample. To compare this result to the Pu-content in geological brines, we obtained a sample from a borehole at the Salton Sea Geothermal field (Southeastern California). In this sample we found an upper concentration limit of (2.1 ± 1.0)x10 -16 g 239 Pu/g sample. (orig.)

Liver acquisition with volume acceleration flex on 70-cm wide-bore and 60-cm conventional-bore 3.0-T MRI.

Science.gov (United States)

Saito, Shigeyoshi; Tanaka, Keiko; Hashido, Takashi

2016-07-01

This study aimed to compare the uniformity of fat suppression and image quality between liver acquisition with volume acceleration flex (LAVA-Flex) and LAVA on 60-cm conventional-bore and 70-cm wide-bore 3.0-T magnetic resonance imaging (MRI). The uniformity of fat suppression by LAVA-Flex and LAVA was assessed as the efficiency of suppression of superficial fat at the levels of the liver dome, porta, and renal hilum. Percentage standard deviation (%SD) was calculated using the following equation: %SD (%) = 100 × SD of the regions of interest (ROIs)/mean value of the signal intensity (SI) in the ROIs. Signal-to-noise ratio (SNR) and contrast ratio (CR) were calculated. In the LAVA sequence, the %SD in all slices on wide-bore 3.0-T MRI was significantly higher than that on conventional-bore 3.0-T MRI (P 3.0-T MRI.

Revisiting resolution in hydrodynamic countercurrent chromatography: tubing bore effect.

Science.gov (United States)

Berthod, A; Faure, K

2015-04-17

A major challenge in countercurrent chromatography (CCC), the technique that works with a support-free biphasic liquid system, is to retain the liquid stationary phase inside the CCC column (Sf parameter). Two solutions are commercially available: the hydrostatic CCC columns, also called centrifugal partition chromatographs (CPC), with disks of interconnected channels and rotary seals, and the hydrodynamic CCC columns with bobbins of coiled open tube and no rotary seals. It was demonstrated that the amount of liquid stationary phase retained by a coiled tube was higher with larger bore tubing than with small bore tubes. At constant column volume, small bore tubing will be longer producing more efficiency than larger bore tube that will better retain the liquid stationary phase. Since the resolution equation in CCC is depending on both column efficiency and stationary phase retention ratio, the influence of the tubing bore should be studied. This theoretical work showed that there is an optimum tubing bore size depending on solute partition coefficient and mobile phase flow rate. The interesting result of the theoretical study is that larger tubing bores allow for dramatically reduced experiment durations for all solutes: in reversed phase CCC (polar mobile phase), hydrophobic solutes are usually highly retained. These apolar solutes can be separated by the same coil at high flow rates and reduced Sf with similar retention times as polar solutes separated at smaller flow rates and much higher Sf. Copyright © 2015 Elsevier B.V. All rights reserved.

Integrated test plan for directional boring

International Nuclear Information System (INIS)

Volk, B.W.

1993-01-01

This integrated test plan describes the field testing of the DITCH WITCH Directional Boring System. DITCH WITCH is a registered trademark of The Charles Machine Works, Inc., Perry, Oklahoma. The test is being conducted as a coordinated effort between Charles Machine Works (CMW), Sandia National Laboratories (SNL), and the Westinghouse Hanford Company (WHC). Funding for the WHC portion of the project is through the Volatile Organic Compound-Arid Integrated Demonstration (VOC-Arid ID). The purpose of the test is to evaluate the performance of the directional boring system for possible future use on environmental restoration projects at Hanford and other Department of Energy (DOE) sites. The test will be conducted near the 200 Areas Fire Station located between the 200 East and 200 West Area of the Hanford Site. The directional boring system will be used to drill and complete (with fiberglass casing) two horizontal boreholes. A third borehole will be drilled to test sampling equipment but will not be completed with casing

Commercializing potassium terbium fluoride, KTF (KTb3F10) faraday crystals for high laser power optical isolator applications

Science.gov (United States)

Schlichting, Wolfgang; Stevens, Kevin; Foundos, Greg; Payne, Alexis

2017-10-01

Many scientific lasers and increasingly industrial laser systems operate in manufacture. However, for high-power laser applications TGG is limited by its absorption at 1064nm and its thermo-optic coefficient, dn/dT. Specifically, thermal lensing and depolarization effects become a limiting factor at high laser powers. While TGG absorption has improved significantly over the past few years, there is an intrinsic limit. Now, SYNOPTICS is commercializing the enhanced new crystal Potassium Terbium Fluoride KTF (KTb3F10) that exhibits much smaller nonlinear refractive index and thermo-optic coefficients, and still exhibits a Verdet constant near that of TGG. This cubic crystal has relatively low absorption and thermo-optic coefficients. It is now fully characterized and available for select production orders. At OPTIFAB in October 2017 we present recent results comparing the performance of KTF to TGG in optical isolators and show SYNOPTICS advances in large volume crystal growth and the production ramp up.

Measuring spacetime: from the big bang to black holes.

Science.gov (United States)

Tegmark, Max

2002-05-24

Space is not a boring static stage on which events unfold over time, but a dynamic entity with curvature, fluctuations, and a rich life of its own. Spectacular measurements of the cosmic microwave background, gravitational lensing, type Ia supernovae, large-scale structure, spectra of the Lyman alpha forest, stellar dynamics, and x-ray binaries are probing the properties of spacetime over 22 orders of magnitude in scale. Current measurements are consistent with an infinite flat everlasting universe containing about 30% cold dark matter, 65% dark energy, and at least two distinct populations of black holes.

Mode I Stress Intensity Factors for triangular corner crack nearby intersecting of cylindrical holes

Directory of Open Access Journals (Sweden)

E. Salvati

2013-10-01

Full Text Available In this paper triangular flaws has been taken into account at the intersection of two holes inside a specified specimen. Influence of bore hole D1/D2 and angle between their axes α are examined. Numerical analysis are performed to determine Stress Intensity factors (SIF in many geometric configurations. Afterwards, fitting weight function’s parameters with FEM results, new SIF analytics expression are shown. Finally, the accuracy of weight functions in SIF predictions for different inner pressure, has been checked as well as the comparison between the SIF of a triangular crack and that of an actual crack shape obtained through a fatigue test.

Investigation on vibrational evaluation criteria for small-bore pipe

International Nuclear Information System (INIS)

Tsuji, Takashi; Maekawa, Akira; Takahashi, Tsuneo; Kato, Minoru; Torigoe, Yuichi

2013-01-01

The well-known organization such as API and SwRI in USA developed criteria for piping vibrational evaluation. These criteria are targeted for main pipes, but not branch pipes with small bore. In this study, applicability of criteria of API and SwRI to branch pipes was investigated. Vibration test using piping system with small bore branch pipe was conducted and amplitudes of vibrational stress and displacement were measured for various exciting force. In comparison of the measurements with the two criteria, though the criteria of API and SwRI were applicable to small bore branch pipe, they made too conservative evaluation. (author)

Continuous measurements of in-bore projectile velocity

International Nuclear Information System (INIS)

Asay, J.R.; Konrad, C.H.; Hall, C.A.; Shahinpoor, M.

1989-01-01

The application of velocity interferometry to the continuous measurement of in-bore projectile velocity in a small-bore three-stage railgun is described. These measurements are useful for determining projectile acceleration and for evaluating gun performance. The launcher employed in these studies consists of a two-stage light gas gun used to inject projectiles into a railgun for additional acceleration. Results obtained for projectile velocities to 7.4 km/s with the two-stage injector are reported and potential improvements for railgun applications are discussed

Bore pile foundation tall buildings closed in the heritage building

Science.gov (United States)

Triastuti, Nusa Setiani

2017-11-01

Bore pile foundation for high building surroundings heritage building should be not damage. Construction proses must good, no necking, no mixed deep water, no sliding soil, nonporous concrete. Objective the execution of bore pile so that heritage buildings and neighboring buildings that are old do not experience cracks, damage and tilting. The survey methodology was observe the process of the implementation of the dominant silt, clay soil, in addition a limited space and to analyze the results of loading tests, investigations of soil and daily reports. Construction process determines the success of the structure bore pile in high building structure bearing, without damaging a heritage building. Attainment the hard soil depth, density concrete, observable clean reinforcement in the implementation. Monitoring the implementation of, among others, the face of the ground water little reduce in the area and outside the footprint of the building, no impact of vibration drilling equipment, watching the mud content on the water coming out at the time of drilling, concrete volume was monitored each 2 m bore depth of pile, The result researched heritage building was not damage. The test results bore pile axial, lateral analyzed the results have the appropriate force design required.

Optimal chest drain size: the rise of the small-bore pleural catheter.

Science.gov (United States)

Fysh, Edward T H; Smith, Nicola A; Lee, Y C Gary

2010-12-01

Drainage of the pleural space is not a modern concept, but the optimal size of chest drains to use remains debated. Conventional teaching advocates blunt dissection and large-bore tubes; but in recent years, small-bore catheters have gained popularity. In the absence of high-quality randomized data, this review summarizes the available literature on the choice of chest drains. The objective data supporting the use of large-bore tubes is scarce in most pleural diseases. Increasing evidence shows that small-bore catheters induce less pain and are of comparable efficacy to large-bore tubes, including in the management of pleural infection, malignant effusion, and pneumothoraces. The onus now is on those who favor large tubes to produce clinical data to justify the more invasive approach. © Thieme Medical Publishers.

Different Techniques For Producing Precision Holes (>20 mm) In Hardened Steel—Comparative Results

Science.gov (United States)

Coelho, R. T.; Tanikawa, S. T.

2009-11-01

High speed machining (HSM), or high performance machining, has been one of the most recent technological advances. When applied to milling operations, using adequate machines, CAM programs and tooling, it allows cutting hardened steels, which was not feasible just a couple of years ago. The use of very stiff and precision machines has created the possibilities of machining holes in hardened steels, such as AISI H13 with 48-50 HRC, using helical interpolations, for example. Such process is particularly useful for holes with diameter bigger than normal solid carbide drills commercially available, around 20 mm, or higher. Such holes may need narrow tolerances, fine surface finishing, which can be obtained just by end milling operations. The present work compares some of the strategies used to obtain such holes by end milling, and also some techniques employed to finish them, by milling, boring and also by fine grinding at the same machine. Results indicate that it is possible to obtain holes with less than 0.36 m in circularity, 7.41 m in cylindricity and 0.12 m in surface roughness Ra. Additionally, there is less possibilities of obtaining heat affected layers when using such technique.

Formulating entompathogens for control of boring beetles in avocado orchards

Science.gov (United States)

A foam formulation of Beauveria bassiana was adapted to control boring beetles in avocado orchards. The two geographically independent avocado growing areas in the United States are threatened by emerging diseases vectored by boring beetles. In the California growing region, Fusarium dieback is vect...

Boring crustaceans damage polystyrene floats under docks polluting marine waters with microplastic.

Science.gov (United States)

Davidson, Timothy M

2012-09-01

Boring isopods damage expanded polystyrene floats under docks and, in the process, expel copious numbers of microplastic particles. This paper describes the impacts of boring isopods in aquaculture facilities and docks, quantifies and discusses the implications of these microplastics, and tests if an alternate foam type prevents boring. Floats from aquaculture facilities and docks were heavily damaged by thousands of isopods and their burrows. Multiple sites in Asia, Australia, Panama, and the USA exhibited evidence of isopod damage. One isopod creates thousands of microplastic particles when excavating a burrow; colonies can expel millions of particles. Microplastics similar in size to these particles may facilitate the spread of non-native species or be ingested by organisms causing physical or toxicological harm. Extruded polystyrene inhibited boring, suggesting this foam may prevent damage in the field. These results reveal boring isopods cause widespread damage to docks and are a novel source of microplastic pollution. Copyright © 2012 Elsevier Ltd. All rights reserved.

Multi-hole seismic modeling in 3-D space and cross-hole seismic tomography analysis for boulder detection

Science.gov (United States)

Cheng, Fei; Liu, Jiangping; Wang, Jing; Zong, Yuquan; Yu, Mingyu

2016-11-01

A boulder stone, a common geological feature in south China, is referred to the remnant of a granite body which has been unevenly weathered. Undetected boulders could adversely impact the schedule and safety of subway construction when using tunnel boring machine (TBM) method. Therefore, boulder detection has always been a key issue demanded to be solved before the construction. Nowadays, cross-hole seismic tomography is a high resolution technique capable of boulder detection, however, the method can only solve for velocity in a 2-D slice between two wells, and the size and central position of the boulder are generally difficult to be accurately obtained. In this paper, the authors conduct a multi-hole wave field simulation and characteristic analysis of a boulder model based on the 3-D elastic wave staggered-grid finite difference theory, and also a 2-D imaging analysis based on first arrival travel time. The results indicate that (1) full wave field records could be obtained from multi-hole seismic wave simulations. Simulation results describe that the seismic wave propagation pattern in cross-hole high-velocity spherical geological bodies is more detailed and can serve as a basis for the wave field analysis. (2) When a cross-hole seismic section cuts through the boulder, the proposed method provides satisfactory cross-hole tomography results; however, when the section is closely positioned to the boulder, such high-velocity object in the 3-D space would impact on the surrounding wave field. The received diffracted wave interferes with the primary wave and in consequence the picked first arrival travel time is not derived from the profile, which results in a false appearance of high-velocity geology features. Finally, the results of 2-D analysis in 3-D modeling space are comparatively analyzed with the physical model test vis-a-vis the effect of high velocity body on the seismic tomographic measurements.

Tracing of paleo-shear zones by self-potential data inversion: case studies from the KTB, Rittsteig, and Grossensees graphite-bearing fault planes

Science.gov (United States)

Mehanee, Salah A.

2015-01-01

This paper describes a new method for tracing paleo-shear zones of the continental crust by self-potential (SP) data inversion. The method falls within the deterministic inversion framework, and it is exclusively applicable for the interpretation of the SP anomalies measured along a profile over sheet-type structures such as conductive thin films of interconnected graphite precipitations formed on shear planes. The inverse method fits a residual SP anomaly by a single thin sheet and recovers the characteristic parameters (depth to the top h, extension in depth a, amplitude coefficient k, and amount and direction of dip θ) of the sheet. This method minimizes an objective functional in the space of the logarithmed and non-logarithmed model parameters (log( h), log( a), log( k), and θ) successively by the steepest descent (SD) and Gauss-Newton (GN) techniques in order to essentially maintain the stability and convergence of this inverse method. Prior to applying the method to real data, its accuracy, convergence, and stability are successfully verified on numerical examples with and without noise. The method is then applied to SP profiles from the German Continental Deep Drilling Program (Kontinentales Tiefbohrprogramm der Bundesrepublik Deutschla - KTB), Rittsteig, and Grossensees sites in Germany for tracing paleo-shear planes coated with graphitic deposits. The comparisons of geologic sections constructed in this paper (based on the proposed deterministic approach) against the existing published interpretations (obtained based on trial-and-error modeling) for the SP data of the KTB and Rittsteig sites have revealed that the deterministic approach suggests some new details that are of some geological significance. The findings of the proposed inverse scheme are supported by available drilling and other geophysical data. Furthermore, the real SP data of the Grossensees site have been interpreted (apparently for the first time ever) by the deterministic inverse

Quality Designed Twin Wire Arc Spraying of Aluminum Bores

Science.gov (United States)

König, Johannes; Lahres, Michael; Methner, Oliver

2015-01-01

After 125 years of development in combustion engines, the attractiveness of these powerplants still gains a great deal of attention. The efficiency of engines has been increased continuously through numerous innovations during the last years. Especially in the field of motor engineering, consequent friction optimization leads to cost-effective fuel consumption advantages and a CO2 reduction. This is the motivation and adjusting lever of NANOSLIDE® from Mercedes-Benz. The twin wire arc-spraying process of the aluminum bore creates a thin, iron-carbon-alloyed coating which is surface-finished through honing. Due to the continuous development in engines, the coating strategies must be adapted in parallel to achieve a quality-conformed coating result. The most important factors to this end are the controlled indemnification of a minimal coating thickness and a homogeneous coating deposition of the complete bore. A specific system enables the measuring and adjusting of the part and the central plunging of the coating torch into the bore to achieve a homogeneous coating thickness. Before and after measurement of the bore diameter enables conclusions about the coating thickness. A software tool specifically developed for coating deposition can transfer this information to a model that predicts the coating deposition as a function of the coating strategy.

Shaft Boring Machine: A method of mechanized vertical shaft excavation

International Nuclear Information System (INIS)

Goodell, T.M.

1991-01-01

The Shaft Boring Machine (SBM) is a vertical application of proven rock boring technology. The machine applies a rotating cutter wheel with disk cutters for shaft excavation. The wheel is thrust against the rock by hydraulic cylinders and slews about the shaft bottom as it rotates. Cuttings are removed by a clam shell device similar to conventional shaft mucking and the muck is hoisted by buckets. The entire machine moves down (and up) the shaft through the use of a system of grippers thrust against the shaft wall. These grippers and their associated cylinders also provide the means to maintain verticality and stability of the machine. The machine applies the same principles as tunnel boring machines but in a vertical mode. Other shaft construction activities such as rock bolting, utility installation and shaft concrete lining can be accomplished concurrent with shaft boring. The method is comparable in cost to conventional sinking to a depth of about 460 meters (1500 feet) beyond which the SBM has a clear host advantage. The SBM has a greater advantage in productivity in that it can excavate significantly faster than drill and blast methods

Evaluation methods of vibration stress of small bore piping

Energy Technology Data Exchange (ETDEWEB)

Hiramatsu, Miki; Sasaki, Toru [Institute of Nuclear Safety System Inc., Mihama, Fukui (Japan)

2001-09-01

Fatigue fracture by vibration stress is one of the main causes of troubles which occur at small bore piping in nuclear power plants. Therefore at the plants they manage small bore piping using a method in which their vibration accelerations are measured and the vibration stresses are calculated. In this work, vibration tests for two sets of mock-ups simulating actual piping in the plants by sinusoidal oscillation and by that obtained at an actual plant were carried out, and then an evaluation method was developed to obtain proper value of vibration stress from the measured data by the vibration tests. In comparison of the vibration stress obtained from the measured acceleration with that directly measured using strain gauges, it is confirmed that accurate vibration stress can be evaluated by a formula in which the real center of gravity of small bore piping and the acceleration of main (system) piping are considered. (author)

The cretaceous/tertiary-boundary impact and its global effects with reference to Australia

International Nuclear Information System (INIS)

Sutherland, F.L.

1996-01-01

Considerable evidence exists for a major meteoritic impact at Chicxulub, Mexico, and its effects at the Cretaceous/Tertiary boundary (KTB). It includes a buried crater, subglobal ejecta, and global fireball deposits that incorporate shocked minerals and non-terrestrial spinels. Platinum-group-element enrichments (Ir anomaly) and marked C- and O-isotope shifts at the KTB coincide with an extinction event. Australia contributes little to the KTB impact story as far, but was isolated from the severest impact and extinction effects. A Chicxulub strike (C- or L-chondrite impactor) explains many KTB features, but does not satisfy all KTB studies. Continuing KTB impact debates include the size of Chicxulub crater, the extent of heterogeneous spinels. The role of KTB plume volcanism (whether impact-induced or not) and the nature of KTB extinctions (whether caused by climatic cooling or warming and whether sharp, gradual or latitudinally reduced) are also in debate. This synthesis suggests that the Chicxulub impact produced a crater 180 km wide and possibly induced tsunamigenic activity; that compositional differences between impact deposits might reflect more that one impact coinciding with the KTB; that the Deccan volcanism predates the KTB in India; and that several KTB studies tentatively suggest maximum impact and subordinate volcanic effects within lower latitudes. 98 refs., 4 figs

Numerical investigations of cooling holes system role in the protection of the walls of a gas turbine combustion chamber

Energy Technology Data Exchange (ETDEWEB)

Ben Sik Ali, Ahlem; Kriaa, Wassim; Mhiri, Hatem [Ecole Nationale D' Ingenieurs de Monastir, Unite de Thermique et Thermodynamique des Procedes industriels, Monastir (Tunisia); Bournot, Philippe [IUSTI, UMR CNRS 6595, Marseille (France)

2012-05-15

Numerical simulations in a gas turbine Swirl stabilized combustor were conducted to investigate the effectiveness of a cooling system in the protection of combustor walls. The studied combustion chamber has a high degree of geometrical complexity related to the injection system as well as the cooling system based on a big distribution of small holes (about 3,390 holes) bored on the flame tube walls. Two cases were considered respectively the flame tube without and with its cooling system. The calculations were carried out using the industrial CFD code FLUENT 6.2. The various simulations made it possible to highlight the role of cooling holes in the protection of the flame tube walls against the high temperatures of the combustion products. In fact, the comparison between the results of the two studied cases demonstrated that the walls temperature can be reduced by about 800 C by the mean of cooling holes technique. (orig.)

Eclogite facies relics and a multistage breakdown in metabasites of the KTB pilot hole, NE Bavaria: implications for the Variscan tectonometamorphic evolution of the NW Bohemian Massif

Science.gov (United States)

O'Brien, Patrick J.; Röhr, Christian; Okrusch, Martin; Patzak, Margarete

1992-11-01

Complex reaction textures in coronitic metagabbros and retrograded eclogites of the KTB pilot and an adjacent drilling provide evidence for a multistage metamorphic history in the Variscan basement of the NW Bohemian Massif. The eclogites show complete metamorphic recrystallization leaving no textural or mineral relics of their igneous precursors. In contrast, textural relics of the igneous protolith are still preserved in the metagabbros where the metamorphic overprint under high pressure conditions achieved only partial replacement of the initial assemblage plagioclase + augite + amphibole (+olivine or orthopyroxene?) + ilmenite to form the eclogite facies assemblage garnet + omphacite + kyanite + zoisite + quartz+rutile. The garnets in the metagabbros occur in the typical ‘necklace’ fashion at the borders between the original plagioclase and mafic phase domains. In the same rocks, omphacite formed by a topotactic reaction mechanism replacing igneous augite as well as in smaller grains at the margins of the texturally igneous clinopyroxene where it occurs without fixed orientation with respect to the relict phase. Both eclogites and metagabbros show a partial breakdown under high pressure granulite (transitional to high pressure amphibolite) facies conditions during which omphacite broke down to vermicular symplectites of diopside + plagioclase. A later pervasive medium pressure metamorphism under amphibolite facies conditions led to the development of assemblages dominated by hornblende + plagioclase+titanite: phases prevailing in the overwhelming majority of the surrounding metabasites. Subsequent vein-associated retrogression produced minerals typical of the greenschist to zeolite facies. All metamorphic stages may be represented in a single thin section but although the overall reaction sequence is apparent, the obvious disequilibrium in the rocks makes the use of conventional geothermobarometry difficult. However, calculations made by assuming an

Procedure for seismic evaluation and design of small bore piping

International Nuclear Information System (INIS)

Bilanin, W.; Sills, S.

1991-01-01

Simplified methods for the seismic design of small bore piping in nuclear power plants have teen used for many years. Various number of designers have developed unique methods to treat the large number of class 2 and 3 small bore piping systems. This practice has led to a proliferation of methods which are not standardized in the industry. These methods are generally based on enveloping the results of rigorous dynamic or conservative static analysis and result in an excessive number of supports and unrealistically high support loadings. Experience and test data have become available which warranted taking another look at the present methods for analysis of small bore piping. A recently completed Electric Power Research Institute and NCIG (a utility group) activity developed a new procedure for the seismic design and evaluation of small bore piping which provides significant safety and cost benefits. The procedure streamlines the approach to inertial stresses, which is the main feature that achieves the new benefits. Criteria in the procedure for seismic anchor movement and support design are based analysis and focus the designer on credible failure mechanisms. A walkdown of the as-constructed piping system to identify and eliminate undesirable piping features such as adverse spatial interaction is required

Empyema and Effusion: Outcome of Image-Guided Small-Bore Catheter Drainage

International Nuclear Information System (INIS)

Keeling, A. N.; Leong, S.; Logan, P. M.; Lee, M. J.

2008-01-01

Empyema and complicated pleural effusion represent common medical problems. Current treatment options are multiple. The purpose of this study was to access the outcome of image-guided, small-bore catheter drainage of empyema and effusion. We evaluated 93 small-bore catheters in 82 patients with pleural effusion (n = 30) or empyema (n = 52), over a 2-year period. Image guidance was with ultrasound (US; n = 56) and CT (n = 37). All patients were followed clinically, with catheter dwell times, catheter outcome, pleural fluid outcome, reinsertion rates, and need for urokinase or surgery recorded. Ninety-three small-bore chest drains (mean=10.2 Fr; range, 8.2-12.2 Fr) were inserted, with an average dwell time of 7.81 days for empyemas and 7.14 days for effusions (p > 0.05). Elective removal rates (73% empyema vs 86% effusions) and dislodgement rates (12% empyema vs 13% effusions) were similar for both groups. Eight percent of catheters became blocked and 17% necessitated reinsertion in empyemas, with no catheters blocked or requiring reinsertion in effusions (p < 0.05). Thirty-two patients (51%) required urokinase in the empyema group, versus 2 patients (6%) in the effusion group (p < 0.05). All treatment failures, requiring surgery, occurred in the empyema group (19%; n = 12; p < 0.05). In conclusion, noninfected pleural collections are adequately treated with small-bore catheters, however, empyemas have a failure rate of 19%. The threshold for using urokinase and larger-bore catheters should be low in empyema

A device for taking samples of scale from bore pipes used for collecting groundwater; Dispositivo para la toma de muestras de incrustaciones en tuberias de sondeos en la captacion de aguas subterraneas

Energy Technology Data Exchange (ETDEWEB)

Martinez Rubio, J.; Ruano Magan, P. [Tecnologias y Servicios Agrarios, S. A. (Spain); Gonzalez Yelamos, J. [Universidad Autonoma de Madrid (Spain); Rebollo Ferreiro, L. F. [Universidad de Alcala (Spain)

2000-07-01

A study was made of the problem of corrosion/scale in water collection bore pipes, beginning with a review of the existing literature. This led to the conclusion that thorough knowledge of such phenomena requires taking samples from the walls of the pipes and filters to determine the physiocochemical and biological details. A new instrument, based on a previous appliance, has been developed for this purpose. It has a pair of arms and is capable of going down inside the well or bore hole, generally with a video camera attached. It has a cup on the end of each arm that can scrape the wall, catch the sample and protect it with a lid. A prototype has proved to be efficient at obtaining representative samples that can be analysed to determine the corrosion/scale processes. (Author) 9 refs.

Railgun bore material test results

International Nuclear Information System (INIS)

Wang, S.Y.; Burton, R.L.; Witherspoon, F.D.; Bloomberg, H.W.; Goldstein, S.A.; Tidman, D.A.; Winsor, N.K.

1987-01-01

GT-Devices, Inc. has constructed a material test facility (MTF) to study the fundamental heat transfer problem of both railgun and electrothermal guns, and to test candidate gun materials under real plasma conditions. The MTF electrothermally produces gigawatt-level plasmas with pulse lengths of 10-30 microseconds. Circular bore and non-circular bore test barrels have been successfully operated under a wide range of simulated heating environments for EM launchers. Diagnostics include piezoelectric MHz pressure probes, time-of-flight probes, and current and voltage probes. Ablation measurements are accomplished by weighing and optical inspection, including borescope, optical microscope, and scanning electron microscope (SEM). From these measurements the ablation threshold for both the rail and insulator materials can be determined as a function of plasma heating. The MTF diagnostics are supported by an unsteady 1-D model of MTF which uses the flux-corrected transport (FCT) algorithm to calculate the fluid equations in conservative form. A major advantage of the FCT algorithm is that it can model gas dynamic shock behaviour without the requirement of numerical diffusion. The principle use of the code is to predict the material surface temperature ΔT/α from the unsteady heat transfer q(t)

30 CFR 18.22 - Boring-type machines equipped for auxiliary face ventilation.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Boring-type machines equipped for auxiliary..., DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and Design Requirements § 18.22 Boring-type machines equipped for...

Ten Years of bored tunnels in the Netherlands : Part I: Geotechnical issues

NARCIS (Netherlands)

Bakker, K.J.; Bezuijen, A.

2008-01-01

Ten years have passed since in 1997 for the first time construction of bored tunnels in the Netherlands soft soil was undertaken. Before that date essentially only immersed tunnels and cut-and-cover tunnels were constructed in the Netherlands. The first two bored tunnels were Pilot Projects, the 2nd

Tunnel Boring Machine Performance Study. Final Report

Science.gov (United States)

1984-06-01

Full face tunnel boring machine "TBM" performance during the excavation of 6 tunnels in sedimentary rock is considered in terms of utilization, penetration rates and cutter wear. The construction records are analyzed and the results are used to inves...

Analysis on pile testing results of post-grouting bored pile

Science.gov (United States)

Zheng, A. R.

2017-04-01

Based on static load test results, the bearing capacity of bored piles with pile-toe and pile-shaft post-grouting has been analyzed. The analysis reveals that: with post-grouting, the interface between pile and surrounding soil are strengthened and the relative sliding displacement in between is reduced; end resistance of pile is enhanced and can be mobilized at earlier stage with smaller sliding displacement. As a result, the performance of bored pile is improved with increased bearing capacity and reduced settlement.

Local response of concrete structures to explosive loading

International Nuclear Information System (INIS)

Freund, H.U.; Krutzik, N.J.; Muller, K.

1989-01-01

This paper reports on the HDR safety program experiments performed concerning demolition of concrete structures and pipes by explosive charges. The precalculability of the local structure reaction as well as that of the global plant was checked. The effect on the bore hole wall by the detonating explosive and the local concrete behavior around the bore hole were investigated. The measured pressure-time history in and around the bore hole is compared with the calculated values. The calculated values seem to be near reality (as far as measurements are available), concerning pressure rise curve within the bore hole and the peak pressure. The analysis of the blow off contours performed with two variations of the material strength of the concrete plates is presented

Grinding tool for making hemispherical bores in hard materials

Science.gov (United States)

Duran, E.L.

1985-04-03

A grinding tool for forming hemispherical bores in hard materials such as boron carbide. The tool comprises a hemicircular grinding bit, formed of a metal bond diamond matrix, which is mounted transversely on one end of a tubular tool shaft. The bit includes a spherically curved outer edge surface which is the active grinding surface of the tool. Two coolant fluid ports on opposite sides of the bit enable introduction of coolant fluid through the bore of the tool shaft so as to be emitted adjacent the opposite sides of the grinding bit, thereby providing optimum cooling of both the workpiece and the bit.

Cutting tool for removing materials from well bore

International Nuclear Information System (INIS)

Lynde, G.D.; Harvey, H.H. Jr.

1991-01-01

This patent describes a cutting tool adapted to be positioned downhole in a well bore for removing a metal member from the well bore; a tool body adapted to be received within said well bore and to be supported at its upper end for rotation about a longitudinal axis; blades at spaced intervals on the body and extending outwardly therefrom, each of the blades having a base with a leading surface relative to the direction of rotation; closely spaced cutting elements of hard cutting material secured to said leading surface of the base in a plurality of transversely extending rows, each cutting element being of a predetermined size and shape and arranged in a predetermined generally symmetrical pattern on the base relative to the other elements, each of said cutting elements having an exposed from cutting face forming a cutting surface, a rear face secured to the leading surface of said base, a peripheral surface extending between said faces, and a relatively sharp edge formed at the juncture of the front face and peripheral surface; the front cutting face of each cutting element being arranged and constructed for directing an extending end portion of a turning cut form said member to effect a breaking of said turning from the member being cut in a predetermined manner to minimize interesting of the turning

Simulation of bearing capacity of bored piles

Directory of Open Access Journals (Sweden)

Majeed Ahmed

2018-01-01

Full Text Available This study focuses on how one can possibly predict the ultimate load for the piles that did not reach failure. This challenge was acquired through Chin- Konder method by which, the estimated settlement that correspond to failure load is well defined. Hence, this research aims to make a comparative study between the results of pile load tests carried out in Al-Basrah sewage treatment plant project, and those results induced from the numerical analysis in term of ultimate pile capacity. Consequently, it may give a clear idea on the ability of numerical simulation in getting close to the actual behavior of piles. In the current study, a numerical study using Plaxis 3D Foundation program has been performed on bored piles by the assistance of site investigations of soil. Mohr- Coulomb and linear elastic models were adopted in the simulation for soil and pile respectively. Ten bored piles were used in this analysis under different values of loading. The diameter and length of pile are 0.6m and 24m respectively. The test results indicate that, an excellent agreement has been found as a response of pile capacity between the field and numerical studies. Also, ideal load- settlement curves were created using Chin- Konder method to predict the failure load of bored piles. Also, the results have demonstrated that, the pile capacity obtained from the simulation process is larger about 51% than that design load estimated before the design of piles. This may present a priority to use the finite element method to be accounted as an effective approach in the primary analysis.

In-bore setup and software for 3T MRI-guided transperineal prostate biopsy

International Nuclear Information System (INIS)

Tokuda, Junichi; Tuncali, Kemal; Song, Sang-Eun; Fedorov, Andriy; Oguro, Sota; Fennessy, Fiona M; Tempany, Clare M; Hata, Nobuhiko; Iordachita, Iulian; Lasso, Andras

2012-01-01

MRI-guided prostate biopsy in conventional closed-bore scanners requires transferring the patient outside the bore during needle insertion due to the constrained in-bore space, causing a safety hazard and limiting image feedback. To address this issue, we present our custom-made in-bore setup and software to support MRI-guided transperineal prostate biopsy in a wide-bore 3 T MRI scanner. The setup consists of a specially designed tabletop and a needle-guiding template with a Z-frame that gives a physician access to the perineum of the patient at the imaging position and allows the physician to perform MRI-guided transperineal biopsy without moving the patient out of the scanner. The software and Z-frame allow registration of the template, target planning and biopsy guidance. Initially, we performed phantom experiments to assess the accuracy of template registration and needle placement in a controlled environment. Subsequently, we embarked on our clinical trial (N = 10). The phantom experiments showed that the translational errors of the template registration along the right–left (RP) and anterior–posterior (AP) axes were 1.1 ± 0.8 and 1.4 ± 1.1 mm, respectively, while the rotational errors around the RL, AP and superior–inferior axes were (0.8 ± 1.0)°, (1.7 ± 1.6)° and (0.0 ± 0.0)°, respectively. The 2D root-mean-square (RMS) needle-placement error was 3 mm. The clinical biopsy procedures were safely carried out in all ten clinical cases with a needle-placement error of 5.4 mm (2D RMS). In conclusion, transperineal prostate biopsy in a wide-bore 3T scanner is feasible using our custom-made tabletop setup and software, which supports manual needle placement without moving the patient out of the magnet. (paper)

Evaluation of an advanced rotor bore examination system

International Nuclear Information System (INIS)

Alford, J.W.

1990-01-01

Evaluations of in-service turbine-generator rotor forgings are often based on an ultrasonic examination of the near-bore region. A portable rotor bore examination system has been developed that provides discontinuity characterization required for a thorough rotor evaluation. This automated system, its procedures and operations personnel have now been qualified for full-scale field application. System development has benefited from merging several technologies with new methods for precise alignment of the drive unit, calibration block and rotor. The system runs a custom interactive software package that allows for flexible calibration and motion control as well as data acquisition and manipulation. A comprehensive evaluation procedure was developed for system qualification using test specimens with natural and artificial reflectors, including a unique fatigue-crack block. Following a discussion of the system features, this paper discusses the system evaluation based on this procedure

Large Bore Powder Gun Qualification (U)

Energy Technology Data Exchange (ETDEWEB)

Rabern, Donald A. [Los Alamos National Laboratory; Valdiviez, Robert [Los Alamos National Laboratory

2012-04-02

A Large Bore Powder Gun (LBPG) is being designed to enable experimentalists to characterize material behavior outside the capabilities of the NNSS JASPER and LANL TA-55 PF-4 guns. The combination of these three guns will create a capability to conduct impact experiments over a wide range of pressures and shock profiles. The Large Bore Powder Gun will be fielded at the Nevada National Security Site (NNSS) U1a Complex. The Complex is nearly 1000 ft below ground with dedicated drifts for testing, instrumentation, and post-shot entombment. To ensure the reliability, safety, and performance of the LBPG, a qualification plan has been established and documented here. Requirements for the LBPG have been established and documented in WE-14-TR-0065 U A, Large Bore Powder Gun Customer Requirements. The document includes the requirements for the physics experiments, the gun and confinement systems, and operations at NNSS. A detailed description of the requirements is established in that document and is referred to and quoted throughout this document. Two Gun and Confinement Systems will be fielded. The Prototype Gun will be used primarily to characterize the gun and confinement performance and be the primary platform for qualification actions. This gun will also be used to investigate and qualify target and diagnostic modifications through the life of the program (U1a.104 Drift). An identical gun, the Physics Gun, will be fielded for confirmatory and Pu experiments (U1a.102D Drift). Both guns will be qualified for operation. The Gun and Confinement System design will be qualified through analysis, inspection, and testing using the Prototype Gun for the majority of process. The Physics Gun will be qualified through inspection and a limited number of qualification tests to ensure performance and behavior equivalent to the Prototype gun. Figure 1.1 shows the partial configuration of U1a and the locations of the Prototype and Physics Gun/Confinement Systems.

Simulation of Single Reed Instruments Oscillations Based on Modal Decomposition of Bore and Reed Dynamics

OpenAIRE

Silva, Fabrice; Debut, Vincent; Kergomard, Jean; Vergez, Christophe; Deblevid, Aude; Guillemain, Philippe

2007-01-01

This paper investigates the sound production in a system made of a bore coupled with a reed valve. Extending previous work (Debut, 2004), the input impedance of the bore is projected on the modes of the air column. The acoustic pressure is therefore calculated as the sum of modal components. The airrrflow blown into the bore is modulated by reed motion, assuming the reed to be a single degree of freedom oscillator. Calculation of self-sustained oscillations controlled by time-varyi...

Large-bore pipe decontamination

International Nuclear Information System (INIS)

Ebadian, M.A.

1998-01-01

The decontamination and decommissioning (D and D) of 1200 buildings within the US Department of Energy-Office of Environmental Management (DOE-EM) Complex will require the disposition of miles of pipe. The disposition of large-bore pipe, in particular, presents difficulties in the area of decontamination and characterization. The pipe is potentially contaminated internally as well as externally. This situation requires a system capable of decontaminating and characterizing both the inside and outside of the pipe. Current decontamination and characterization systems are not designed for application to this geometry, making the direct disposal of piping systems necessary in many cases. The pipe often creates voids in the disposal cell, which requires the pipe to be cut in half or filled with a grout material. These methods are labor intensive and costly to perform on large volumes of pipe. Direct disposal does not take advantage of recycling, which could provide monetary dividends. To facilitate the decontamination and characterization of large-bore piping and thereby reduce the volume of piping required for disposal, a detailed analysis will be conducted to document the pipe remediation problem set; determine potential technologies to solve this remediation problem set; design and laboratory test potential decontamination and characterization technologies; fabricate a prototype system; provide a cost-benefit analysis of the proposed system; and transfer the technology to industry. This report summarizes the activities performed during fiscal year 1997 and describes the planned activities for fiscal year 1998. Accomplishments for FY97 include the development of the applicable and relevant and appropriate regulations, the screening of decontamination and characterization technologies, and the selection and initial design of the decontamination system

Disinfection of bore well water with chlorine dioxide/sodium hypochlorite and hydrodynamic cavitation.

Science.gov (United States)

Wang, Yifei; Jia, Aiyin; Wu, Yue; Wu, Chunde; Chen, Lijun

2015-01-01

The effect of hydrodynamic cavitation (HC) on potable water disinfection of chemicals was investigated. The bore well water was introduced into HC set-up to examine the effect of HC alone and combination of HC and chemicals such as chlorine dioxide and sodium hypochlorite. The effect of inlet pressure and geometrical parameters on disinfection was studied using HC alone and the results showed that increasing inlet pressure and using more and bigger holes of orifice plates can result in a higher disinfection rates. When HC was combined with chemicals, HC can reduce the doses of the chemicals and shorten the time of disinfection. It was also found that the decrease in bacteria concentration followed a first-order kinetic model. As for the experiment of combination of HC and sodium hypochlorite for disinfection, HC not only improves the disinfection rate but also degrades natural organic matter and chloroform. Compared with only sodium hypochlorite disinfection, combined processes get higher disinfection rate and lower production of chloroform, particularly the pretreatment with HC enhances the disinfection rate by 32% and there is a simultaneous reduction in production of chloroform by 39%.

Seismic response and damping tests of small bore LMFBR piping and supports

International Nuclear Information System (INIS)

Barta, D.A.; Anderson, M.J.; Severud, L.K.; Lindquist, M.R.

1984-01-01

Seismic testing and analysis of a prototypical Liquid Metal Fast Breeder Reactor (LMFBR) small bore piping system is described. Measured responses to simulated seismic excitations are compared with analytical predictions based on NRC Regulatory Guide 1.61 and measured system damping values. The test specimen was representative of a typical LMFBR insulated small bore piping system, and it was supported from a rigid test frame by prototypic dead weight supports, mechanical snubbers and pipe clamps

Looking ahead of a tunnel boring machine with 2-D SH full waveform inversion

NARCIS (Netherlands)

Pisupati, P.B.; Mulder, W.A.; Drijkoningen, G.G.; Reijnen, R.

2015-01-01

In the near-surface with unconsolidated soils, shear properties can be well imaged, sometimes better than P-wave properties. To facilitate ground prediction ahead of a tunnel boring machine (TBM), active ‘surveys’ with shear-wave vibrators are carried out during boring. In such surveys, only a few

Boring sponges (Porifera, Clionidae) collected during the "Tydeman" Canary Islands expedition Cancap-II, 1977

NARCIS (Netherlands)

Groot, de R.A.

1980-01-01

INTRODUCTION AND MATERIAL The boring sponges of the Canary Islands have never been studied in any detail, but the boring fauna of this archipelago cannot be expected to be very rich. All islands are volcanic and calcareous rocks are not common. Consequently, in most areas large shells and rhodophyte

Nuclear fuel elements

International Nuclear Information System (INIS)

Nakai, Keiichi

1983-01-01

Purpose: To decrease the tensile stresses resulted in a fuel can as well as prevent decladding of fuel pellets into the bore holes by decreasing the inner pressure within the nuclear fuel element. Constitution: A fuel can is filled with hollow fuel pellets, inserted with a spring for retaining the hollow fuel pellets with an appropriate force and, thereafter, closely sealed at the both ends with end plugs. A cylindrical body is disposed into the bore holes of the hollow fuel pellets. Since initial sealing gases and/or gaseous nuclear fission products can thus be excluded from the bore holes where the temperature is at the highest level, the inner pressure of the nuclear fuel element can be reduced to decrease the tensile strength resulted to the fuel can. Furthermore, decladding of fuel pellets into the bore holes can be prevented. (Moriyama, K.)

Bore erosion due to plasma armatures in EM launchers

International Nuclear Information System (INIS)

Askew, R.F.; Brown, J.L.; Jensen, D.B.

1987-01-01

Bore erosion, both to insulators and rails, has been a major concern in the EM Launcher community. Plasma armatures have generally produced both melting and ablation from the rails, with the result that the surface texture of the rails is course and uneven upon resolidification. Ablation evidence for insulators varies with material but mass lose by decomposition appears prevalent. Theoretical models for EML performance, both one and two dimensional, have a strong dependence on armature mass, which is turn is influenced by rail and insulator ablation. Ablation models are strongly dependent on the armature plasma temperature. In order to test the accuracy of models detailed information is needed on the time dependence of the in-bore plasma parameters such as pressure, temperature, and electron density. Previously reported experimental data indicated that mechanisms other than plasma radiation are involved in the ablation process. New experiments have been conducted using a small, square bore (1 cm) facility, 60 cm in length, to quantify the erosions and to relate this to conditions within the armature and possible plasma chemistry processes at the rails and insulators. Mass loss has been measured as a function of position on both the rails and insulators. These have been correlated with the time history of the gas dynamic pressure at that location. In addition, the armature current time history has been correlated with the pressure

Environmental impact of a flocculant used to enhance solids transport during well bore clean-up operations

International Nuclear Information System (INIS)

Yunus, M.N.M.; Procyk, A.D.; Malbrel, C.A.; Ling, K.L.C.

1995-01-01

This paper investigates particle flocculation as a mechanism to remove residual contaminants in well bores during completion operations. Laboratory tests and field trials were conducted demonstrating the ability of flocculating polymer sweeps to improve well bore cleaning efficiency. This process reduces the volume of fluid accumulated in the well bore that is discharged to the environment and minimizes the risk of formation damage by residuals left in the well bore. In addition, a comprehensive environmental impact study was performed on the flocculating polymers which included 72 hrs-EC50, 48 hrs-LC50, 10 day- LC50 tests on a variety of marine organisms, and bioaccumulation and biodegradability tests. In all cases, the flocculating polymers were shown to be environmentally safe at the recommended concentrations

Development of a screening procedure for vibrational fatigue in small bore piping

International Nuclear Information System (INIS)

Smith, J.K.; Riccardella, P.C.; Gosselin, S.R.

1995-01-01

Approximately 80% of the documented fatigue failures in nuclear power plants are caused by high cycle vibrational fatigue. These failures typically occur in socket welded pipe fittings in small bore piping (2 in. nominal diameter and smaller). These failures have been unexpected, and have caused costly, unscheduled outages in some cases. In order to reduce the number of vibrational fatigue failures in operating nuclear power plants, a vibrational fatigue screening procedure has been developed under Electric Power Research Institute (EPRI) sponsorship. The purpose of this paper is to describe this procedure, and to discuss topics related to vibrational fatigue failures. These topics include sources of vibration in nuclear power plants, the effect of socket welds on vibrational fatigue failures, vibrational fatigue screening criteria for small bore piping systems, and good design practices for reducing the number of vibrational fatigue failures in small bore piping

Incident wave, infragravity wave, and non-linear low-frequency bore evolution across fringing coral reefs

Science.gov (United States)

Storlazzi, C. D.; Griffioen, D.; Cheriton, O. M.

2016-12-01

Coral reefs have been shown to significantly attenuate incident wave energy and thus provide protection for 100s of millions of people globally. To better constrain wave dynamics and wave-driven water levels over fringing coral reefs, a 4-month deployment of wave and tide gauges was conducted across two shore-normal transects on Roi-Namur Island and two transects on Kwajalein Island in the Republic of the Marshall Islands. At all locations, although incident wave (periods 250 s) heights on the outer reef flat just inshore of the zone of wave breaking, the infragravity wave heights generally equaled the incident wave heights by the middle of the reef flat and exceeded the incident wave heights on the inner reef flat by the shoreline. The infragravity waves generally were asymmetric, positively skewed, bore-like forms with incident-band waves riding the infragravity wave crest at the head of the bore; these wave packets have similar structure to high-frequency internal waves on an internal wave bore. Bore height was shown to scale with water depth, offshore wave height, and offshore wave period. For a given tidal elevation, with increasing offshore wave heights, such bores occurred more frequently on the middle reef flat, whereas they occurred less frequently on the inner reef flat. Skewed, asymmetric waves are known to drive large gradients in velocity and shear stress that can transport material onshore. Thus, a better understanding of these low-frequency, energetic bores on reef flats is critical to forecasting how coral reef-lined coasts may respond to sea-level rise and climate change.

Analytical and Numerical Modeling of Tsunami Wave Propagation for double layer state in Bore

Science.gov (United States)

Yuvaraj, V.; Rajasekaran, S.; Nagarajan, D.

2018-04-01

Tsunami wave enters into the river bore in the landslide. Tsunami wave propagation are described in two-layer states. The velocity and amplitude of the tsunami wave propagation are calculated using the double layer. The numerical and analytical solutions are given for the nonlinear equation of motion of the wave propagation in a bore.

A foam formulation of an entomopathogenic fungus for control of boring beetles in avocado orchards

Science.gov (United States)

A foam formulation of Beauveria bassiana was adapted to control boring beetles in avocado orchards. The two geographically independent avocado growing areas in the United States are threatened by emerging diseases vectored by boring beetles. In the California growing region, Fusarium dieback is vect...

Solid-to-hybrid transitioning armature railgun with non-conforming-to-prejudice bore profile

Science.gov (United States)

Solberg, Jerome Michael

2012-12-04

An improved railgun, railgun barrel, railgun projectile, and railgun system for accelerating a solid-to-hybrid transitioning armature projectile using a barrel having a bore that does not conform to a cross-sectional profile of the projectile, to contact and guide the projectile only by the rails in a low pressure bore volume so as to minimize damage, failure, and/or underperformance caused by plasma armatures, insulator ablation, and/or restrikes.

Ethylene glycol as bore fluid for hollow fiber membrane preparation

KAUST Repository

Le, Ngoc Lieu

2017-03-31

We proposed the use of ethylene glycol and its mixture with water as bore fluid for the preparation of poly(ether imide) (PEI) hollow fiber membranes and compared their performance and morphology with membranes obtained with conventional coagulants (water and its mixture with the solvent N-methylpyrrolidone (NMP)). Thermodynamics and kinetics of the systems were investigated. Water and 1:1 water:EG mixtures lead to fast precipitation rates. Slow precipitation is observed for both pure EG and 9:1 NMP:water mixture, but the reasons for that are different. While low osmotic driving force leads to slow NMP and water transport when NMP:water is used, the high EG viscosity is the reason for the slow phase separation when EG is the bore fluid. The NMP:water mixture produces fibers with mixed sponge-like and finger-like structure with large pores in the inner and outer layers; and hence leading to a high water permeance and a high MWCO suitable for separation of large-sized proteins. As compared to NMP:water, using EG as bore fluid provides fibers with a finger-like bilayered structure and sponge-like layers near the surfaces, and hence contributing to the higher water permeance. It also induces small pores for better protein rejection.

Ethylene glycol as bore fluid for hollow fiber membrane preparation

KAUST Repository

Le, Ngoc Lieu; Nunes, Suzana Pereira

2017-01-01

We proposed the use of ethylene glycol and its mixture with water as bore fluid for the preparation of poly(ether imide) (PEI) hollow fiber membranes and compared their performance and morphology with membranes obtained with conventional coagulants (water and its mixture with the solvent N-methylpyrrolidone (NMP)). Thermodynamics and kinetics of the systems were investigated. Water and 1:1 water:EG mixtures lead to fast precipitation rates. Slow precipitation is observed for both pure EG and 9:1 NMP:water mixture, but the reasons for that are different. While low osmotic driving force leads to slow NMP and water transport when NMP:water is used, the high EG viscosity is the reason for the slow phase separation when EG is the bore fluid. The NMP:water mixture produces fibers with mixed sponge-like and finger-like structure with large pores in the inner and outer layers; and hence leading to a high water permeance and a high MWCO suitable for separation of large-sized proteins. As compared to NMP:water, using EG as bore fluid provides fibers with a finger-like bilayered structure and sponge-like layers near the surfaces, and hence contributing to the higher water permeance. It also induces small pores for better protein rejection.

Acoustic Monitoring for Tunnel Boring in Soft Soils

NARCIS (Netherlands)

Swinnen, G.

2003-01-01

The TBM, not a blind mole! This thesis deals with some aspects of seismic imaging of the soft soil in front of a Tunnel Boring Machine to help tunnel constructors ``see'' the subsurface they are approaching, instead of steering the TBM forward like a ``blind mole''. The Dutch shallow subsurface has

Tunnel Boring Machine for nuclear waste repository research project

International Nuclear Information System (INIS)

Janzon, H.A.

1994-01-01

A description is presented of a Tunnel Boring Machine and its intended use on a research project underway in Sweden for demonstrating and testing methods for rock investigation at a suitable depth for a deep repository for nuclear waste

The evolution of an internal bore at the Malin shelf break

Directory of Open Access Journals (Sweden)

J. Small

1999-04-01

Full Text Available Observations of internal waves were made at the Malin shelf edge during SESAME (Shelf Edge Studies Acoustic Measurement Experiment, a part of the NERC LOIS-SES experiment, in August-September 1996. These measurements provide a high resolution dataset demonstrating internal wave generation and propagation. This note presents observations of the evolution of an internal bore. The process is shown clearly in a sequence of thermistor chain tows across the shelf break covering a complete tidal cycle, as the double-sided bore transforms into a group of undulations and eventually into more distinct solitary waveforms. Current structures associated with the bore and waves were also observed by ship-mounted ADCP. Analysis of the waveforms in terms of the linear modes and empirical orthogonal functions (EOFs indicate the dominance of the first mode, which is typical of a shallow water seasonal thermocline environment. Determination of the phase speed of the waves from the consecutive ship surveys enabled the Doppler shift in the towed data to be removed, allowing analysis of the real length scales of the waves. The bore evolution has been modelled using a first order non-linear KdV model for the first mode, initialised with the waveform in the first survey. Comparison of the model and the observations show close agreement in the amplitudes, length scales, phase speeds and separations of the leading internal waves as they evolve. Finally, analysis of the observed internal wave shapes indicates that, within the uncertainties of measurement, the wave-lengths lie between those predicted by first and second order soliton theory.Key words. Oceanography: general (continental shelf processes; ocean prediction. Oceanography: physical (internal and inertial waves

The evolution of an internal bore at the Malin shelf break

Directory of Open Access Journals (Sweden)

J. Small

Full Text Available Observations of internal waves were made at the Malin shelf edge during SESAME (Shelf Edge Studies Acoustic Measurement Experiment, a part of the NERC LOIS-SES experiment, in August-September 1996. These measurements provide a high resolution dataset demonstrating internal wave generation and propagation. This note presents observations of the evolution of an internal bore. The process is shown clearly in a sequence of thermistor chain tows across the shelf break covering a complete tidal cycle, as the double-sided bore transforms into a group of undulations and eventually into more distinct solitary waveforms. Current structures associated with the bore and waves were also observed by ship-mounted ADCP. Analysis of the waveforms in terms of the linear modes and empirical orthogonal functions (EOFs indicate the dominance of the first mode, which is typical of a shallow water seasonal thermocline environment. Determination of the phase speed of the waves from the consecutive ship surveys enabled the Doppler shift in the towed data to be removed, allowing analysis of the real length scales of the waves. The bore evolution has been modelled using a first order non-linear KdV model for the first mode, initialised with the waveform in the first survey. Comparison of the model and the observations show close agreement in the amplitudes, length scales, phase speeds and separations of the leading internal waves as they evolve. Finally, analysis of the observed internal wave shapes indicates that, within the uncertainties of measurement, the wave-lengths lie between those predicted by first and second order soliton theory.

Key words. Oceanography: general (continental shelf processes; ocean prediction. Oceanography: physical (internal and inertial waves

Use of bore logging for the determination of lithological characteristics of the Boom clay formation and interest for correlations in clay

International Nuclear Information System (INIS)

Neerdael, B.; Bonne, A.; Manfroy, P.; Vandenberghe, N.; Fierens, E.; Laga, P.

1981-01-01

It is first recalled that the purpose of the HADES project of the CEN/SCK at Mol (Belgium) is to study the possibility of geological disposal for radioactive wastes in the Boom clay formation at a depth between +-160 and 270 m. The different steps and aspects of the site investigation are exposed, and for each of them, the specific techniques used are reviewed. One of these steps is elaborated more in detail. It covers namely the lateral extrapolation of the lithological variations as established from a very detailed analysis of the initial cored boring. Among the usefull methods, the most practical and refined results were obtained from the resistivity logs in the reconnaissance holes. Finally, examples are shown of very detailed correlation on site scale, scale of the hydrogeological entity and regional scale (occurrence of Boom clay on the belgian territory)

Flow and turbulence structure in a hypertidal estuary with the world's biggest tidal bore

Science.gov (United States)

Tu, Junbiao; Fan, Daidu

2017-04-01

Turbulent and flow structure associated with breaking tidal bores are deliberately investigated on the basis of field measurements. High-resolution velocity and hydrographic data are collected in the middle Qiantang Estuary by a vertical array of acoustic Doppler velocimeters and optical backscatter sensors, collaborated with a bottom-mounted acoustic Doppler current profiler. Besides obvious variations in diurnal and spring-neap tidal cycles, the estuarine dynamics is featured by extreme asymmetry in flood and ebb tides. The flood tide is abnormally accelerated to generate tidal bores at the first 10 min or more, with breaking or undular configurations at the front. The occurrence of peak flow velocity, turbulent kinetic energy (TKE), and TKE dissipation rate (ɛ) is definitely associated with breaking bores, with their values several times to 2 orders of magnitude larger than the corresponding secondary peak values during the maximum ebb flows. Flow and turbulence dynamics are significantly affected by the tidal-bore Froude number. A sandwich ɛ structure is clear exhibited with the maximum value at the surface, secondary maximum near the bed, and the minimum at the intermediate. Dual TKE sources are indicated by an approximate local balance between shear production and dissipation near the bottom, and a top-down TKE dissipation using the modified Froude scaling in the vertical water column. The highly elevated dissipation by breaking bores is comparable to that by intense breaking waves in the surf zone, and the former potentially penetrates the entire water column to produce extreme sediment-resuspension events in combination with intense bottom shear stress.

An Analysis of the Guided Wave Patterns in a Small-bore Titanium Tube by a Magnetostrictive Sensor Technique

International Nuclear Information System (INIS)

Cheong, Yong-Moo; Kim, Shin

2007-01-01

The presence of damage or defects in pipes or tubes is one of the major problems in nuclear power plants. However, in many cases, it is difficult to inspect all of them by the conventional ultrasonic methods, because of their geometrical complexity and inaccessibility. The magnetostrictive guided wave technique has several advantages for practical applications, such as a 100- percent volumetric coverage of a long segment of a structure, a reduced inspection time and its cost effectiveness, as well as its' relatively simple structure. One promising feature of the magnetostrictive sensor technique is that the wave patterns are relatively clear and simple compared to the conventional piezoelectric ultrasonic transducer. If we can characterize the evolution of the defect signals, it can be a promising tool for a structural health monitoring of pipes for a long period as well as the identification of flaws. An in-bore guided wave probe was developed for an application to small bore heat exchanger tubes. The magnetostrictive probe installed on the hollow cylindrical waveguide generates and detects torsional waves in the waveguide. This waveguide is expanded by the draw bar to create an intimate mechanical contact between the waveguide and the inside surface of the tube being tested. In this paper, we analyzed the wave patterns reflected from various artificial holes in a titanium tube, which is used in the condenser in a nuclear power plant. The torsional guided waves were generated and received by a coil and a DC magnetized nickel strip as well as an inbore guided wave probe. The wave patterns from various defects were compared with two different sensor techniques and a detectable limit of the defected was estimated

The Bored Self in Knowledge Work

DEFF Research Database (Denmark)

Costas, Jana; Kärreman, Dan

2016-01-01

of the bored self as a combination of unfilled aspirations and the sense of stagnation, leading to an arrested identity. Our contribution is to expand extant conceptualizations of employee interactions with identity regulation, in particular relating to identity work and identification. The findings provide......This article draws attention to reported experiences of boredom in knowledge work. Drawing on extensive qualitative data gathered at two management consultancy firms, we analyze these experiences as a particular interaction with identity regulation and work experiences. We conceptualize the reports...

Separation of amino acids and antibiotics by narrow-bore and normal-bore high-performance liquid chromatography with pre-column derivatization.

Science.gov (United States)

Fiedler, H P; Plaga, A

1987-01-16

The selectivity, efficiency and lifetime of normal- and narrow-bore columns for high-performance liquid chromatography were investigated for the separation and quantification of amino acids and the amino acid-like antibiotics phosphinothricin and phosphinothricylalanylalanine in biological samples. These compounds were determined by an automated pre-column derivatization with o-phthalaldehyde-2-mercaptoethanol reagent and UV detection at 338 nm.

Tunnel boring machine applications

International Nuclear Information System (INIS)

Bhattacharyya, K.K.; McDonald, R.; Saunders, R.S.

1992-01-01

This paper reports that characterization of Yucca Mountain for a potential repository requires construction of an underground Exploratory Studies Facility (ESF). Mechanical excavating methods have been proposed for construction of the ESF as they offer a number of advantages over drilling and blasting at the Yucca Mountain site, including; less ground disturbance and therefore a potential for less adverse effects on the integrity of the site, creation of a more stable excavation cross section requiring less ground support, and an inherently safer and cleaner working environment. The tunnel boring machine (TBM) provides a proven technology for excavating the welded and unwelded Yucca Mountain tuffs. The access ramps and main underground tunnels form the largest part of the ESF underground construction work, and have been designed for excavation by TBM

In-Bore MR-Guided Biopsy Systems and Utility of PI-RADS.

Science.gov (United States)

Fütterer, Jurgen J; Moche, Michael; Busse, Harald; Yakar, Derya

2016-06-01

A diagnostic dilemma exists in cases wherein a patient with clinical suspicion for prostate cancer has a negative transrectal ultrasound-guided biopsy session. Although transrectal ultrasound-guided biopsy is the standard of care, a paradigm shift is being observed. In biopsy-naive patients and patients with at least 1 negative biopsy session, multiparametric magnetic resonance imaging (MRI) is being utilized for tumor detection and subsequent targeting. Several commercial devices are now available for targeted prostate biopsy ranging from transrectal ultrasound-MR fusion biopsy to in bore MR-guided biopsy. In this review, we will give an update on the current status of in-bore MRI-guided biopsy systems and discuss value of prostate imaging-reporting and data system (PIRADS).

Tubular bending and pull-out forces in high-curvature well bores

International Nuclear Information System (INIS)

Dareing, D.W.; Ahlers, C.A.

1991-01-01

This paper is concerned with drag forces developed on tubulars in high-curvature well bores typically found in drainhole and horizontal drilling. The dog-leg severity of these types of boreholes are considerably higher than those typically found in conventional directional drilling. The objective of the study was to determine the significance of bending stiffness on drag forces in the pull-out mode. The method of analysis treats the tubular as a multi-spanned curved beam under tension and solves for radial displacements, slope, shear and bending moment over each span. Calculations show that bending stiffness is a minor factor provided there are no locally severe dog legs superimposed in the high-curvature well bore

White holes and eternal black holes

International Nuclear Information System (INIS)

Hsu, Stephen D H

2012-01-01

We investigate isolated white holes surrounded by vacuum, which correspond to the time reversal of eternal black holes that do not evaporate. We show that isolated white holes produce quasi-thermal Hawking radiation. The time reversal of this radiation, incident on a black hole precursor, constitutes a special preparation that will cause the black hole to become eternal. (paper)

Late Permian wood-borings reveal an intricate network of ecological relationships.

Science.gov (United States)

Feng, Zhuo; Wang, Jun; Rößler, Ronny; Ślipiński, Adam; Labandeira, Conrad

2017-09-15

Beetles are the most diverse group of macroscopic organisms since the mid-Mesozoic. Much of beetle speciosity is attributable to myriad life habits, particularly diverse-feeding strategies involving interactions with plant substrates, such as wood. However, the life habits and early evolution of wood-boring beetles remain shrouded in mystery from a limited fossil record. Here we report new material from the upper Permian (Changhsingian Stage, ca. 254-252 million-years ago) of China documenting a microcosm of ecological associations involving a polyphagan wood-borer consuming cambial and wood tissues of the conifer Ningxiaites specialis. This earliest evidence for a component community of several trophically interacting taxa is frozen in time by exceptional preservation. The combination of an entry tunnel through bark, a cambium mother gallery, and up to 11 eggs placed in lateral niches-from which emerge multi-instar larval tunnels that consume cambium, wood and bark-is ecologically convergent with Early Cretaceous bark-beetle borings 120 million-years later.Numerous gaps remain in our knowledge of how groups of organisms interacted in ancient ecosystems. Here, Feng and colleagues describe a late Permian fossil wood-boring beetle microcosm, with the oldest known example of complex tunnel geometry, host tissue response, and the presence of fungi within.

Measurement of Antenna Bore-Sight Gain

Science.gov (United States)

Fortinberry, Jarrod; Shumpert, Thomas H.

2016-01-01

The absolute or free-field gain of a simple antenna can be approximated using standard antenna theory formulae or for a more accurate prediction, numerical methods may be employed to solve for antenna parameters including gain. Both of these methods will result in relatively reasonable estimates but in practice antenna gain is usually verified and documented via measurements and calibration. In this paper, a relatively simple and low-cost, yet effective means of determining the bore-sight free-field gain of a VHF/UHF antenna is proposed by using the Brewster angle relationship.

Tension Tests On Bored Piles In Sand

DEFF Research Database (Denmark)

Krabbenhøft, Sven; Clausen, Johan; Damkilde, Lars

2006-01-01

The lengths of the bored piles varied from 2 m to 6 m and all were of a diameter of 140 mm. The piles were tested to failure in tension and the load-displacement relations were recorded. The investigation has shown pronounced differences between the load bearing capacities obtained by different...... design methods. The methods proposed by Fleming et al. and Reese & O’Neill seem to produce the best match with the test results....

Development of self-boring type pressuremeter and proposal of empirical formula to estimate mechanical properties of gravelly soil

International Nuclear Information System (INIS)

Yoshida, Yasuo; Ikemi, Motonobu; Kokusho, Takaji

1990-01-01

Diluvial gravelly grounds seem to have the great potential as the foundation ground for constructing nuclear power plants. The Central Research Institute of Electric Power Industry develops the in-situ testing method to evaluate the settlement and the stability of the foundations of important nuclear power plant structures against earthquakes. As a part of the development, the CRIEPI has developed a new self boring type pressure meter which enables a probe to penetrate into gravelly deposit with minimum disturbance. This equipment can impose static or dynamic repeated pressure on bore walls. In this report, the test results of this equipment used in five gravelly grounds in Japan are described. The test results were compared with those obtained by other methods, and the efficiency of this in situ method was demonstrated. The bore wall pressurizing tester which can be inserted simultaneously with boring was developed, and its features are the effects of stress release and bore wall disturbance are little. Consequently, the accurate data on ground stability can be obtained. (K.I.)

Downhole instrument including a flexible probe which can travel freely around bends in a borehole

International Nuclear Information System (INIS)

Dickinson III, B. W. O.

1985-01-01

Bore hole instrument and methods of manufacturing and using the same. The instrument includes an elongated flexible probe which is inserted into a bore hole and can travel freely around bends of relatively short radius in the hole. The probe includes a plurality of sensors, explosive charges or the like which are spaced apart and embedded in a flexible body comprising a mass of cushioning material, with a flexible outer casing of fabric having a high tensile strength. The probe is driven into a bore hole in piston-like fashion, and the flexible body enables the probe to travel freely around bends of relatively short radius. Instrumentation for processing signals from the probe is located at the surface of the earth, and a flexible cable interconnects the instrumentation with the probe

Preliminary Study for Development of Welds Integrity Verification Equipment for the Small Bore Piping

International Nuclear Information System (INIS)

Choi, Geun Suk; Lee, Jong Eun; Ryu, Jung Hoon; Cho, Kyoung Youn; Sohn, Myoung Sung; Lee, Sanghoon; Sung, Gi Ho; Cho, Hong Seok

2016-01-01

It has been reported leakage accident of small-bore piping in Korea. Leakage accident of small-bore pipes are those that will increase due to the aging of the nuclear power plant. And if leakage of the pipe is repaired by using the clamping device when it occur accident, it is economically benefits. The clamping device is a fastening device used to hold or secure objects tightly together to prevent movement or separation through the application of inward pressure. However, when the accident occurs, it can't immediately respond because maintenance and repairing technology are not institutionalized in KEPIC. Thus it appears an economic loss. The technology for corresponding thereto is necessary for the safety of the operation of nuclear power plants. The purpose of this research is to develop an online repairing technology of socket welded pipe and vibration monitoring system of small-bore pipe in the nuclear power plant. Specifically, detailed studies are as follows : • Development of weld overlay method of safety class socket welded connections • Development of Mechanical Clamping Devices for Safety Class 2, 3 small-bore pipe. The purpose of this study is to develop an online repairing technology of socket welded pipe and vibration monitoring system of small-bore pipe, resulting in degraded plant systems. And it is necessary to institutionalize the technology. The fatigue crack testing of socket welded overlay will be performed and fatigue life evaluation method will be developed in second year. Also prototype fabrication of mechanical clamping device will be completed. Base on final goal, the intent is to propose practical evaluation tools, design and fabrication methods for socket welded connection integrity. And result of this study is to development of KEPIC code case approved technology for on-line repairing system of socket welded connection and fabrication of mechanical clamping device

Navigated MRI-guided liver biopsies in a closed-bore scanner: experience in 52 patients.

Science.gov (United States)

Moche, Michael; Heinig, Susann; Garnov, Nikita; Fuchs, Jochen; Petersen, Tim-Ole; Seider, Daniel; Brandmaier, Philipp; Kahn, Thomas; Busse, Harald

2016-08-01

To evaluate clinical effectiveness and diagnostic efficiency of a navigation device for MR-guided biopsies of focal liver lesions in a closed-bore scanner. In 52 patients, 55 biopsies were performed. An add-on MR navigation system with optical instrument tracking was used for image guidance and biopsy device insertion outside the bore. Fast control imaging allowed visualization of the true needle position at any time. The biopsy workflow and procedure duration were recorded. Histological analysis and clinical course/outcome were used to calculate sensitivity, specificity and diagnostic accuracy. Fifty-four of 55 liver biopsies were performed successfully with the system. No major and four minor complications occurred. Mean tumour size was 23 ± 14 mm and the skin-to-target length ranged from 22 to 177 mm. In 39 cases, access path was double oblique. Sensitivity, specificity and diagnostic accuracy were 88 %, 100 % and 92 %, respectively. The mean procedure time was 51 ± 12 min, whereas the puncture itself lasted 16 ± 6 min. On average, four control scans were taken. Using this navigation device, biopsies of poorly visible and difficult accessible liver lesions could be performed safely and reliably in a closed-bore MRI scanner. The system can be easily implemented in clinical routine workflow. • Targeted liver biopsies could be reliably performed in a closed-bore MRI. • The navigation system allows for image guidance outside of the scanner bore. • Assisted MRI-guided biopsies are helpful for focal lesions with a difficult access. • Successful integration of the method in clinical workflow was shown. • Subsequent system installation in an existing MRI environment is feasible.

Intense Undular Bores on the Autumn Pycnocline of Shelf Waters of the Peter the Great Bay (Sea of Japan)

Science.gov (United States)

Dolgikh, G. I.; Novotryasov, V. V.; Yaroshchuk, I. O.; Permyakov, M. S.

2018-03-01

The results of field observations of an internal undular bore that were performed in a coastal zone of constant depth in the Sea of Japan are presented. A hydrodynamic model of undular bores is discussed according to which the recorded disturbances of the water medium are an experimental prototype of strongly nonlinear (intense) internal undular bores on the pycnocline of shelf waters of Peter the Great Bay with an intensity close to the limit.

Tri-bore PVDF hollow fibers with a super-hydrophobic coating for membrane distillation

KAUST Repository

Lu, Kang-Jia; Zuo, Jian; Chung, Tai-Shung

2016-01-01

Membranes with good mechanical strength, high vapor flux and outstanding anti-wetting properties are essential for membrane distillation (MD) applications. In this work, porous polyvinylidene fluoride (PVDF) tri-bore hollow fiber membranes with super-hydrophobicity are developed to achieve these desired properties. The tri-bore hollow fiber offers better mechanical strength than the conventional single-bore fiber. To improve its anti-wetting properties, Teflon® AF 2400 is coated on the membrane surface. The effects of coating on membrane morphology, performance and anti-wetting properties have been thoroughly investigated. With an optimal coating condition (0.025 wt% of Teflon® AF 2400, 30 s), a super-hydrophobic surface with a contact angle of 151o is achieved. The resultant membrane shows an increase of 109% in liquid entry pressure (LEP) with a slight sacrifice of 21% in flux. Long term direct contact MD tests have confirmed that the Teflon® AF 2400 coated membrane has enhanced stability with an average flux of 21 kg m-2 h-1 and rejection of 99.99% at 60 °° C for desalination application.

Tri-bore PVDF hollow fibers with a super-hydrophobic coating for membrane distillation

KAUST Repository

Lu, Kang-Jia

2016-04-26

Membranes with good mechanical strength, high vapor flux and outstanding anti-wetting properties are essential for membrane distillation (MD) applications. In this work, porous polyvinylidene fluoride (PVDF) tri-bore hollow fiber membranes with super-hydrophobicity are developed to achieve these desired properties. The tri-bore hollow fiber offers better mechanical strength than the conventional single-bore fiber. To improve its anti-wetting properties, Teflon® AF 2400 is coated on the membrane surface. The effects of coating on membrane morphology, performance and anti-wetting properties have been thoroughly investigated. With an optimal coating condition (0.025 wt% of Teflon® AF 2400, 30 s), a super-hydrophobic surface with a contact angle of 151o is achieved. The resultant membrane shows an increase of 109% in liquid entry pressure (LEP) with a slight sacrifice of 21% in flux. Long term direct contact MD tests have confirmed that the Teflon® AF 2400 coated membrane has enhanced stability with an average flux of 21 kg m-2 h-1 and rejection of 99.99% at 60 °° C for desalination application.

Boresonic inspection of steam turbine and generator spindles with the Tomoscan

International Nuclear Information System (INIS)

Dube, N.; Bertholotti, D.; Yates, D.

1990-01-01

Steam turbine rotors in power utility plants can generate cracks and ultimately fail after long period of use. The inspection of rotors is done on a regular basis and particular attention is paid to areas near bore holes. An automated ultrasound system has been developed to control and ensure the quality of rotor bore holes of steam turbine rotors

Data for calibration and validation of numerical models at SFR Nuclear Waste Repository

International Nuclear Information System (INIS)

Axelsson, Carl-Lennart

1997-12-01

The final repository for low and intermediate radioactive waste, SFR, is located below the Baltic, offshore of the nuclear power plant at Forsmark. The current operating permit for SKB stipulates that the safety assessment is updated at least every ten year. In response, SKB has started the SAFE project which aims at submitting a complete revised safety analysis before or during the year 2000. The current report is part of the far-field analyses in SAFE and provides information that can be used in a revised hydrogeological modelling of the facility. Information have been collected mainly during the construction phase of SFR, 1983 - 88, and the operation phase from 1988. The specific information that is available for the construction phase is: pressure responses in different bore holes when pumping in one bore hole, groundwater pressure in sections of bore holes, inflow to different parts of the SFR, and groundwater chemistry and isotope analyses in sections of bore holes. During the operation phase, the following information is available: ground-water pressure in sections of bore holes, inflow to different parts of the SFR facility, and groundwater chemistry and isotope analyses in sections of bore holes. The important issues in the groundwater modelling for the performance assessment study of SFR is the amount of water that flows through the storage caverns and the silo together with the possible retention and adsorption in the rock mass, i.e. the flow paths from the repository parts. Thus, the most important type of information is the inflow measurements made in different parts of SFR. The groundwater chemistry may be used to understand the flow pattern and mixing of water with various origin such as fresh groundwater, saline rock/fracture groundwater and Baltic Sea water, especially to predict breakthrough time for the Baltic Sea water at different bore hole sections in fracture zones. The report discusses especially the availability and evolution of inflow and

Compact and air-transportable ultrasonic turbine disc bore inspection system

International Nuclear Information System (INIS)

Larsen, R.E.; Leon-Salamanca, T.

1990-01-01

A compact, lightweight, air-transportable ultrasonic inspection system for bore and keyway regions of shrunk-on turbine discs has been developed. The system utilizes a proprietary ultrasound liquid coupling technique in conjunction with a single pair of gimballed search units to achieve rapid and thorough coverage of bores and keyways in both heavy nuclear and standard fossil discs of nearly any size and having any conceivable web surface contour. Search unit positioning and angulation parameter settings are established in near real-time through a computation algorithm based on a compact vector ray tracing protocol. Modular construction and the use of lightweight, stiff materials throughout facilitates air shipment of the system and its rapid deployment at continental and overseas field sites. Mechanical and ultrasonic features of the system are described. Development and application of the computation algorithm to the ultrasonic inspection of heavy discs at an overseas power station is discussed

Development of Inspection Technique for Socket Weld of Small Bore Piping in Nuclear Power Plant

International Nuclear Information System (INIS)

Yoon, Byungsik; Kim, Yongsik; Lee, Jeongseok

2013-01-01

The losses incurred by unplanned shutdowns are significant; consequently, early crack initiation and crack detection, including the detection of fillet weld manufacturing defects, is of the utmost importance. Current inspection techniques are not capable of reliably inspecting socket welds; therefore, new approaches are needed. The new technique must be sensitive to socket weld cracking, which usually initiates from the root, in order to detect the cracking during the early failure phase. In 2008, Kori unit 3 experienced leakage from the drain line socket weld of a steam generator. From this experience, KHNP enforced a management program to focus on enhancing the reliability of small bore socket weld piping inspections. Currently, conventional manual ultrasonic inspection techniques are used to detect service induced fatigue cracks. But there was uncertainty on manual ultrasonic inspection because of limited access to the welds and difficulties with contact between the ultrasonic probe and the OD surface of small bore piping. In this study, phased array ultrasonic inspection techniques are applied to increase inspection speed and reliability. Additionally a manually encoded scanner has been developed to enhance contact conditions and maintain constant signal quality. A phased array UT technique and system was developed to inspect small bore socket welds. The experimental results show all artificial flaws in the specimen were detected and measured. These experimental results show, that the newly developed inspection system, has improved the reliability and speed of small bore socket weld inspection. Based on these results, future works shall focus on additional experiments, with more realistic flaw responses. By applying this technique to the field, we expect that it can improve the integrity of small bore piping in nuclear power plants

A finite element thermohydrodynamic analyis of profile bore bearing

International Nuclear Information System (INIS)

Shah Nor bin Basri

1994-01-01

A finite element-based method is presented for analysing the thermohydrodynamic (THD) behaviour of profile bore bearing. A variational statement for the governing equation is derived and used to formulate a non-linear quadrilateral finite element of serendipity family. The predicted behaviour is compared with experimental evidence where possible and favorable correlation is obtained

Retained foreign body following pleural drainage with a small-bore catheter.

Science.gov (United States)

Paddle, Alenka; Elahi, Maqsood; Newcomb, Andrew

2010-01-01

Small-bore radiopaque drains can be used to drain pleural effusions. They offer reliable drainage of simple pleural effusions and provide a safe, less-invasive, more comfortable alternative to the standard tube thoracostomy. Importantly, removal of such drains does not require purse-string sutures and hence can be removed without assistance. We report here the cautionary tale of a retained foreign body related to drainage of a pleural effusion with a Pleurocath in a patient following cardiac surgery to raise awareness of this potential complication. Emphasized is the need for all staff to be familiar with the normal appearance of equipment being utilized in the ward and to report when incomplete removal of drain equipment is suspected. In addition, amendments to insertion techniques for such small-bore drains are proposed to avoid similar undue complications.

Exploring the role of wood waste landfills in early detection of non-native alien wood-boring beetles

Science.gov (United States)

Davide Rassati; Massimo Faccoli; Lorenzo Marini; Robert A. Haack; Andrea Battisti; Edoardo. Petrucco Toffolo

2015-01-01

Non-native wood-boring beetles (Coleoptera) represent one of the most commonly intercepted groups of insects at ports worldwide. The development of early detection methods is a crucial step when implementing rapid response programs so that non-native wood-boring beetles can be quickly detected and a timely action plan can be produced. However, due to the limited...

External Microflora of a Marine Wood-Boring Isopod

OpenAIRE

Boyle, Paul J.; Mitchell, Ralph

1981-01-01

Bacteria associated with the marine wood-boring isopod Limnoria lignorum were enumerated by acridine orange epifluorescence microscopy and by plate counts on several media; the plate-viable bacteria were isolated and identified. Similar procedures were followed to enumerate and identify bacteria associated with the wood substrate from which the isopods were collected and with the surrounding water from the isopod habitat. Approximately 1.4 × 107 bacterial cells were associated with each indiv...

Recent development in the design of hard rock tunnel boring machines for the mining industry

International Nuclear Information System (INIS)

Snyder, L.L.; Williams, R.I.

1991-01-01

Underground development for nuclear waste storage will possibly require tunnels to be excavated in a variety of rock conditions and configurations. Recent innovations in Tunnel Boring Machine (TBM) design have allowed for an evolved style of TBM which has distinct advantages over the standard machines. Present day conventional hard rock TBM's were developed primarily for the long, relatively straight tunnels of the civil construction industry, thereby making them for the most part, unsuitable for the sharp curves, turnouts, declines, inclines and ramps required in many underground environments. The five foot to 36 foot (1.52 to 11 m) diameter machines are capable of boring tunnels with curve radiuses as small as 40 to 90 feet (12.2 to 27.5 m) depending on size. These short turning radiuses can be accomplished while gripping the tunnel walls horizontally in the traditional manner or vertically as required when intersecting existing tunnels, or making turnouts from the tunnel that the machine has just bored. The machine's length is approximately half of a traditional machine's length while still employing a full measure of thrust, horsepower and rock cutting ability. The machine's short length, combined with a patented machine structure allows it to steer while boring without causing harmful eccentric loads on the cutterhead and main bearing assembly. The machine configuration is versatile and can be easily modified to operate in a wide variety of conditions

Small-bore chest tubes seem to perform better than larger tubes in treatment of spontaneous pneumothorax

DEFF Research Database (Denmark)

Iepsen, Ulrik Winning; Ringbæk, Thomas

2013-01-01

The aim of this study was to compare the efficacy and complications of surgical (large-bore) chest tube drainage with smaller and less invasive chest tubes in the treatment of non-traumatic pneumothorax (PT). ......The aim of this study was to compare the efficacy and complications of surgical (large-bore) chest tube drainage with smaller and less invasive chest tubes in the treatment of non-traumatic pneumothorax (PT). ...

High-resolution Hg Chemostratigraphy

DEFF Research Database (Denmark)

Sial, Alcides N.; Chen, J.; Lacerda, L.D.

2014-01-01

of Gubbio (Italy) and Stevns Klint (Denmark) where the KTB layer is easily recognizable, and at a near-complete succession exposed at the Bajada del Jagüel locality in the Neuquén Basin, Argentina. These three localities display similar δ13Ccarb trends with markedly negative excursion at the KTB layer. Bulk-rock...... one at Stevns Klint points to a cycle of warm followed by colder climate. At Stevns Klint, Hg contents reach 250 ng g− 1 within the KTB layer (Fiskeler Member) and 45 ng.g− 1 at 1.5 m above that, while within the Scaglia Rossa Formation at Gubbio, three Hg peaks across the KTB are observed, one...

Four-layer, two-inch bore, superconducting dipole magnet

International Nuclear Information System (INIS)

Hassenzahl, W.V.; Peters, C.; Gilbert, W.; Taylor, C.; Meuser, R.

1982-11-01

Superconductors provide the accelerator designer with a unique opportunity to construct machines that can achieve high particle energies and yet have low operating costs. This paper describes the design, fabrication and testing of a 4 layer, 50 mm bore superconducting dipole magnet, D-9A. The magnet reached short sample, 5.8 T at 4.4 K and 8.0 T and 1.8 K, with little training, and exhibited low losses and low ramp rate sensitivity

Study on tsunami damage mechanism in Fukushima Prefecture focusing on the generation of bores

International Nuclear Information System (INIS)

Okuma, Shohei; Sato, Shinji; Yamanaka, Yusuke; Sanuki, Hiroshi

2015-01-01

Destruction mechanisms of coastal structures due to the 2011 Tohoku Tsunami were investigated on the basis of field surveys in Fukushima Prefecture. Severe destruction appeared to be developed by the action of breaking bores. Laboratory experiments demonstrated that the angle of the tsunami front was an essential parameter for the generation of breaking bores. Larger wave force was observed as the angle of the tsunami front became steeper. Numerical simulation revealed that such a steep tsunami was developed in the central part of Fukushima Prefecture, where the reflection of the preceding tsunami by coastal cliff enhanced the steepness of the largest tsunami. (author)

Tunnelling in Soft Soil : Tunnel Boring Machine Operation and Soil Response

NARCIS (Netherlands)

Festa, D.; Broere, W.; Bosch, J.W.

2013-01-01

Constructing tunnels in soft soil with the use of Tunnel Boring Machines may induce settlements including soil movements ahead of the face, soil relaxation into the tail void, possible heave due to grouting, long lasting consolidation processes, and potentially several other mechanisms. A

Pressure bump instability in very large cold bore storage rings

International Nuclear Information System (INIS)

Limon, P.

1983-12-01

Calculations have been done to estimate the circulating current necessary to induce the onset of a pressure bump instability in a cold bore storage ring. For a wide range of storage ring parameters, the instability threshold current is more than an order of magnitude higher than the operating current. 4 references, 2 tables

Space-borne observation of mesospheric bore by Visible and near Infrared Spectral Imager onboard the International Space Station

Science.gov (United States)

Hozumi, Y.; Saito, A.; Sakanoi, T.; Yamazaki, A.; Hosokawa, K.

2017-12-01

Mesospheric bores were observed by Visible and near Infrared Spectral Imager (VISI) of the ISS-IMAP mission (Ionosphere, Mesosphere, upper Atmosphere and Plasmasphere mapping mission from the International Space Station) in O2 airglow at 762 nm wavelength. The mesospheric bore is moving front of sharp jump followed by undulations or turbulence in the mesopause region. Since previous studies of mesospheric bore were mainly based on ground-based airglow imaging that is limited in field-of-view and observing site, little is known about its horizontal extent and global behavior. Space-borne imaging by ISS-IMAP/VISI provides an opportunity to study the mesospheric bore with a wide field-of-view and global coverage. A mesospheric bore was captured by VISI in two consecutive paths on 9 July 2015 over the south of African continent (48ºS - 54ºS and 15ºE). The wave front aligned with south-north direction and propagated to west. The phase velocity and wave length of the following undulation were estimated to 100 m/s and 30 km, respectively. Those parameters are similar to those reported by previous studies. 30º anti-clockwise rotation of the wave front was recognized in 100 min. Another mesospheric bore was captured on 9 May 2013 over the south Atlantic ocean (35ºS - 43ºS and 24ºW - 1ºE) with more than 2,200 km horizontal extent of wave front. The wave front aligned with southeast-northwest direction. Because the following undulation is recognized in the southwest side of the wave front, it is estimated to propagate to northeast direction. The wave front was modulated with 1,000 km wave length. This modulation implies inhomogeneity of the phase velocity.

Black holes

International Nuclear Information System (INIS)

Feast, M.W.

1981-01-01

This article deals with two questions, namely whether it is possible for black holes to exist, and if the answer is yes, whether we have found any yet. In deciding whether black holes can exist or not the central role in the shaping of our universe played by the forse of gravity is discussed, and in deciding whether we are likely to find black holes in the universe the author looks at the way stars evolve, as well as white dwarfs and neutron stars. He also discusses the problem how to detect a black hole, possible black holes, a southern black hole, massive black holes, as well as why black holes are studied

A study of the complications of small bore 'Seldinger' intercostal chest drains.

Science.gov (United States)

Davies, Helen E; Merchant, Shairoz; McGown, Anne

2008-06-01

Use of small bore chest drains (drainage over a 12-month period. One hundred consecutive small bore Seldinger (12F) chest drain insertions were evaluated. Few serious complications occurred. However, 21% of the chest drains were displaced ('fell out') and 9% of the drains became blocked. This contributed to high morbidity rates, with 13% of patients requiring repeat pleural procedures. The frequency of drain blockage in pleural effusion was reduced by administration of regular normal saline drain flushes (odds ratio for blockage in flushed drains compared with non-flushed drains 0.04, 95% CI: 0.01-0.37, P < 0.001). Regular chest drain flushes are advocated in order to reduce rates of drain blockage, and further studies are needed to determine optimal fixation strategies that may reduce associated patient morbidity.

Wood-Boring Bivalves (Mollusca: Teredinidae, Pholadidae) of Pacific coast of Colombia

International Nuclear Information System (INIS)

Cantera K, Jaime R

2010-01-01

Twelve species of wood-boring bivalves, ten of the family Teredinidae and two of family Pholadidae were collected in mangroves at 6 locations of the Pacific coast of Colombia. This paper presents a brief escription of these species, including size, ecological notes and geographical distribution.

Gun bore flaw image matching based on improved SIFT descriptor

Science.gov (United States)

Zeng, Luan; Xiong, Wei; Zhai, You

2013-01-01

In order to increase the operation speed and matching ability of SIFT algorithm, the SIFT descriptor and matching strategy are improved. First, a method of constructing feature descriptor based on sector area is proposed. By computing the gradients histogram of location bins which are parted into 6 sector areas, a descriptor with 48 dimensions is constituted. It can reduce the dimension of feature vector and decrease the complexity of structuring descriptor. Second, it introduce a strategy that partitions the circular region into 6 identical sector areas starting from the dominate orientation. Consequently, the computational complexity is reduced due to cancellation of rotation operation for the area. The experimental results indicate that comparing with the OpenCV SIFT arithmetic, the average matching speed of the new method increase by about 55.86%. The matching veracity can be increased even under some variation of view point, illumination, rotation, scale and out of focus. The new method got satisfied results in gun bore flaw image matching. Keywords: Metrology, Flaw image matching, Gun bore, Feature descriptor

σ-holes and π-holes: Similarities and differences.

Science.gov (United States)

Politzer, Peter; Murray, Jane S

2018-04-05

σ-Holes and π-holes are regions of molecules with electronic densities lower than their surroundings. There are often positive electrostatic potentials associated with them. Through these potentials, the molecule can interact attractively with negative sites, such as lone pairs, π electrons, and anions. Such noncovalent interactions, "σ-hole bonding" and "π-hole bonding," are increasingly recognized as being important in a number of different areas. In this article, we discuss and compare the natures and characteristics of σ-holes and π-holes, and factors that influence the strengths and locations of the resulting electrostatic potentials. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Investigation of the structure of filter cakes from bore flushing

Energy Technology Data Exchange (ETDEWEB)

Hartmann, A; Oezerler, M; Marx, C; Hartmann, A; Oezerler, M; Marx, C; Poege, S; Young, F

1985-01-01

After a description of the tasks and functions of the filter cake in bores, the requirements for filter cakes are explained. The aim of the investigation is finding a correlation between the filter cake structures and the prehistory of flushing. The technique of preparing the samples and previous results from investigations with electron microscopes are introduced and discussed.

Chemical and mechanical bioerosion of boring sponges from Mexican Pacific coral reefs.

Science.gov (United States)

Nava, Héctor; Carballo, José Luis

2008-09-01

Species richness (S) and frequency of invasion (IF) by boring sponges on living colonies of Pocillopora spp. from National Park Isla Isabel (México, East Pacific Ocean) are presented. Twelve species belonging to the genera Aka, Cliona, Pione, Thoosa and Spheciospongia were found, and 56% of coral colonies were invaded by boring sponges, with Cliona vermifera Hancock 1867 being the most abundant species (30%). Carbonate dissolution rate and sediment production were quantified for C. vermifera and Cliona flavifodina Rützler 1974. Both species exhibited similar rates of calcium carbonate (CaCO3) dissolution (1.2+/-0.4 and 0.5+/-0.2 kg CaCO3 m(-2) year(-1), respectively, mean +/- s.e.m.), and sediment production (3.3+/-0.6 and 4.6+/-0.5 kg CaCO3 m(-2) year(-1)), resulting in mean bioerosion rates of 4.5+/-0.9 and 5.1+/-0.5 kg CaCO3 m(-2) year(-1), respectively. These bioerosion rates are close to previous records of coral calcification per unit of area, suggesting that sponge bioerosion alone can promote disequilibrium in the reef accretion/destruction ratio in localities that are heavily invaded by boring sponges. The proportion of dissolved material by C. vermifera and C. flavifodina (27 and 10.2%, respectively) confirms that chemical bioerosion plays an important role in sponge bioerosion and in the CaCO3 cycle in coral reefs.

High Frequency Field Measurements of an Undular Bore Using a 2D LiDAR Scanner

Directory of Open Access Journals (Sweden)

Kévin Martins

2017-05-01

Full Text Available The secondary wave field associated with undular tidal bores (known as whelps has been barely studied in field conditions: the wave field can be strongly non-hydrostatic, and the turbidity is generally high. In situ measurements based on pressure or acoustic signals can therefore be limited or inadequate. The intermittent nature of this process in the field and the complications encountered in the downscaling to laboratory conditions also render its study difficult. Here, we present a new methodology based on LiDAR technology to provide high spatial and temporal resolution measurements of the free surface of an undular tidal bore. A wave-by-wave analysis is performed on the whelps, and comparisons between LiDAR, acoustic and pressure-derived measurements are used to quantify the non-hydrostatic nature of this phenomenon. A correction based on linear wave theory applied on individual wave properties improves the results from the pressure transducer (Root mean square error, R M S E of 0 . 19 m against 0 . 38 m; however, more robust data is obtained from an upwards-looking acoustic sensor despite high turbidity during the passage of the whelps ( R M S E of 0 . 05 m. Finally, the LiDAR scanner provides the unique possibility to study the wave geometry: the distribution of measured wave height, period, celerity, steepness and wavelength are presented. It is found that the highest wave from the whelps can be steeper than the bore front, explaining why breaking events are sometimes observed in the secondary wave field of undular tidal bores.

Automating horizontal boring and milling machine

International Nuclear Information System (INIS)

Naqvi, S.A.R.; Mahmood, T.; Choudhry, M.A.; Hanif, A.

2012-01-01

Aiming at the requirements of modification for many old import machine tools in industry, the schemes suited to the renovation are presented in this paper. A horizontal boring and milling machine (HBM) involved in machining of tank Al-Khalid has been modified using Mitsubishi FX-1N and FX-2N PLC. The developed software is for control of all the functions of the said machine. These functions include power on/off oil pump, spindle rotation and machine movement in all axes. All the decisions required by the machine for actuation of instructions are based on the data acquired from the control panel, timers and limit switches. Also the developed software minimize the down time, safety of operator and error free actuation of instructions. (author)

Estimation of strength parameters of small-bore metal-polymer pipes

Science.gov (United States)

Shaydakov, V. V.; Chernova, K. V.; Penzin, A. V.

2018-03-01

The paper presents results from a set of laboratory studies of strength parameters of small-bore metal-polymer pipes of type TG-5/15. A wave method was used to estimate the provisional modulus of elasticity of the metal-polymer material of the pipes. Longitudinal deformation, transverse deformation and leak-off pressure were determined experimentally, with considerations for mechanical damage and pipe bend.

Nuclear piping and pipe support design and operability relating to loadings and small bore piping

International Nuclear Information System (INIS)

Stout, D.H.; Tubbs, J.M.; Callaway, W.O.; Tang, H.T.; Van Duyne, D.A.

1994-01-01

The present nuclear piping system design practices for loadings, multiple support design and small bore piping evaluation are overly conservative. The paper discusses the results developed for realistic definitions of loadings and loading combinations with methodology for combining loads under various conditions for supports and multiple support design. The paper also discusses a simplified method developed for performing deadweight and thermal evaluations of small bore piping systems. Although the simplified method is oriented towards the qualification of piping in older plants, this approach is applicable to plants designed to any edition of the ASME Section III or B31.1 piping codes

Black hole astrophysics

International Nuclear Information System (INIS)

Blandford, R.D.; Thorne, K.S.

1979-01-01

Following an introductory section, the subject is discussed under the headings: on the character of research in black hole astrophysics; isolated holes produced by collapse of normal stars; black holes in binary systems; black holes in globular clusters; black holes in quasars and active galactic nuclei; primordial black holes; concluding remarks on the present state of research in black hole astrophysics. (U.K.)

Chatter reduction in boring process by using piezoelectric shunt damping with experimental verification

Science.gov (United States)

Yigit, Ufuk; Cigeroglu, Ender; Budak, Erhan

2017-09-01

Chatter is a self-excited type of vibration that develops during machining due to process-structure dynamic interactions resulting in modulated chip thickness. Chatter is an important problem as it results in poor surface quality, reduced productivity and tool life. The stability of a cutting process is strongly influenced by the frequency response function (FRF) at the cutting point. In this study, the effect of piezoelectric shunt damping on chatter vibrations in a boring process is studied. In piezoelectric shunt damping method, an electrical impedance is connected to a piezoelectric transducer which is bonded on cutting tool. Electrical impedance of the circuit consisting of piezoceramic transducer and passive shunt is tuned to the desired natural frequency of the cutting tool in order to maximize damping. The optimum damping is achieved in analytical and finite element models (FEM) by using a genetic algorithm focusing on the real part of the tool point FRF rather than the amplitude. Later, a practical boring bar is considered where the optimum circuit parameters are obtained by the FEM. Afterwards, the effect of the optimized piezoelectric shunt damping on the dynamic rigidity and absolute stability limit of the cutting process are investigated experimentally by modal analysis and cutting tests. It is both theoretically and experimentally shown that application of piezoelectric shunt damping results in a significant increase in the absolute stability limit in boring operations.

Applying the information received in the process of drilling for the estimation of the state of rocks

Energy Technology Data Exchange (ETDEWEB)

Denissov, N Ya; Paushkin, G A; Zaytzev, A S

1966-01-01

In estimating rock foundations for construction, data on the condition of the degree of jointing and weathering are of major importance. For estimating the condition, (in particular, data on core recovery and the speed of boring) drill holes are used. In this paper it is shown that the data on core recovery during the boring of drill holes in regions with complex tectonics can give a wrong idea about the state of rock. However, data on the speed of clean boring may prove to be useful. In some cases low core recovery and its large crushing are caused by the influence of the heterogeneity of rock composition as well as by the influence of changes in the stressed state of rock during boring. The data on the speed of clean boring can be used in engineering geological practice to estimate the intensity and character of spreading rock jointing and to determine the depth of weathering penetration.

Development of large bore superconducting magnet for wastewater treatment application

Energy Technology Data Exchange (ETDEWEB)

Liu, Hui Ming; Xu, Dong; Shen, Fuzhi; Zhang, Hengcheng; Li, Lafeng [State Key Laboratory of Technologies in Space Cryogenic Propellants, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing (China)

2017-03-15

Water issue, especially water pollution, is a serious issue of 21st century. Being an significant technique for securing water resources, superconducting magnetic separation wastewater system was indispensable. A large bore conduction-cooled magnet was custom-tailored for wastewater treatment. The superconducting magnet has been designed, fabricated and tested. The superconducting magnet was composed of NbTi solenoid coils with an effective horizontal warm bore of 400 mm and a maximum central field of 2.56T. The superconducting magnet system was cooled by a two-stage 1.5W 4K GM cryocooler. The NbTi solenoid coils were wound around an aluminum former that is thermally connected to the second stage cold head of the cryocooler through a conductive copper link. The temperature distribution along the conductive link was measured during the cool-down process as well as at steady state. The magnet was cooled down to 4.8K in approximately 65 hours. The test of the magnetic field and quench analysis has been performed to verify the safe operation for the magnet system. Experimental results show that the superconducting magnet reached the designed magnetic performance.

SHORT-PULSE ELECTROMAGNETIC TRANSPONDER FOR HOLE-TO-HOLE USE.

Science.gov (United States)

Wright, David L.; Watts, Raymond D.; Bramsoe, Erik

1983-01-01

Hole-to-hole observations were made through nearly 20 m of granite using an electromagnetic transponder (an active reflector) in one borehole and a single-hole short-pulse radar in another. The transponder is inexpensive, operationally simple, and effective in extending the capability of a short-pulse borehole radar system to allow hole-to-hole operation without requiring timing cables. A detector in the transponder senses the arrival of each pulse from the radar. Each pulse detection triggers a kilovolt-amplitude pulse for retransmission. The transponder 'echo' may be stronger than that of a passive reflector by a factor of as much as 120 db. The result is an increase in range capability by a factor which depends on attenuation in the medium and hole-to-hole wavepath geometry.

Automatic detection of ''bore slug'' in tubes; Detection automatique des manques de metal internes sur tubes

Energy Technology Data Exchange (ETDEWEB)

Bisiaux, B.; Deutsch, S.; Tailleux, O.; Mette, F. [CEV Vallourec, Aulnoye (France)

2001-07-01

During the tube manufacturing for the petroleum industry, the lacks of internal metal (called Bore Slug) can be created during the hot rolling. These large defects are not good detected by the classic UT and by the wall thickness measurement. That's why VALLOUREC developed an automatic UT device which works by transmission. Nevertheless, this system is too little selective and can cause no doubtful pipes (tubes good detected bad). We adapted a Bore Slug control system on the VMOG UK RP20 at the end of August. The results are rather good and showed a good detection of the Bore Slug and very little no doubtful pipes. (authors)

Black holes

OpenAIRE

Brügmann, B.; Ghez, A. M.; Greiner, J.

2001-01-01

Recent progress in black hole research is illustrated by three examples. We discuss the observational challenges that were met to show that a supermassive black hole exists at the center of our galaxy. Stellar-size black holes have been studied in x-ray binaries and microquasars. Finally, numerical simulations have become possible for the merger of black hole binaries.

Internal-bore-welding of 2 1/4 Cr--1 Mo steel tube-to-tubesheet joints

International Nuclear Information System (INIS)

Moorhead, A.J.; Slaughter, G.M.

1976-01-01

In order to avoid the disadvantages of the conventional face-side tube-to-tubesheet weld, the steam generators for the Clinch River Breeder Reactor Plant (a power-producing demonstration LMFBR) will be built using a relatively new technique known as internal-bore-welding (IBW). In IBW the tube does not pass through the tubesheet but rather is welded to a short stub machined on the tube side of the tubesheet. This joint has the important advantages of being inspectable by radiography and eliminating the crevice; however, it is much more difficult to weld than is the face-side design. Because of the close proximity of the tubes, there is not room for an orbiting-arc welding head on the outside of the tube. Consequently, this weld must be made by welding from the inside- or bore-side of the tube. The results are presented of the initial phases of a program undertaken at ORNL to develop improved bore-side welding equipment, to gain further understanding of this technique, and to develop mechanical property data for autogeneous welds in 2 1/4 Cr-1 Mo steel tube and tubesheet materials

Edwin G. Boring: The Historian's Path in the Pages of The American Journal of Psychology.

Science.gov (United States)

Gallagher, Shawn R

2017-01-01

Although he is best known for his classic textbook, A History of Experimental Psychology, Edwin Garrigues Boring published dozens of articles in The American Journal of Psychology and used its various formats to guide the discipline in the early 20th century. This report reviews a small sample of his publications, including obituaries, notes, and experimental articles, and presents them in historical and biographical context. A central objective is to show how Boring shared the values of his structuralist training with the emerging American schools and how time allowed him to reconsider his approach to history and the legacy of his iconic mentor, Edward Bradford Titchener.

Imaging system models for small-bore DOI-PET scanners

International Nuclear Information System (INIS)

Takahashi, Hisashi; Kobayashi, Tetsuya; Yamaya, Taiga; Murayama, Hideo; Kitamura, Keishi; Hasegawa, Tomoyuki; Suga, Mikio

2006-01-01

Depth-of-interaction (DOI) information, which improves resolution uniformity in the field of view (FOV), is expected to lead to high-sensitivity PET scanners with small-bore detector rings. We are developing small-bore PET scanners with DOI detectors arranged in hexagonal or overlapped tetragonal patterns for small animal imaging or mammography. It is necessary to optimize the imaging system model because these scanners exhibit irregular detector sampling. In this work, we compared two imaging system models: (a) a parallel sub-LOR model in which the detector response functions (DRFs) are assumed to be uniform along the line of responses (LORs) and (b) a sub-crystal model in which each crystal is divided into a set of smaller volumes. These two models were applied to the overlapped tetragonal scanner (FOV 38.1 mm in diameter) and the hexagonal scanner (FOV 85.2 mm in diameter) simulated by GATE. We showed that the resolution non-uniformity of system model (b) was improved by 40% compared with that of system model (a) in the overlapped tetragonal scanner and that the resolution non-uniformity of system model (a) was improved by 18% compared with that of system model (b) in the hexagonal scanner. These results indicate that system model (b) should be applied to the overlapped tetragonal scanner and system model (a) should be applied to the hexagonal scanner. (author)

Plasma immersion ion implantation of the interior surface of a large cylindrical bore using an auxiliary electrode

International Nuclear Information System (INIS)

Zeng, X.C.; Kwok, T.K.; Liu, A.G.; Chu, P.K.; Tang, B.Y.

1998-01-01

A model utilizing cold, unmagnetized, and collisionless fluid ions as well as Boltzmann electrons is used to comprehensively investigate the sheath expansion into a translationally invariant large bore in the presence of an auxiliary electrode during plasma immersion ion implantation (PIII) of a cylindrical bore sample. The governing equation of ion continuity, ion motion, and Poisson close-quote s equation are solved by using a numerical finite difference method for different cylindrical bore radii, auxiliary electrode radii, and voltage rise times. The ion density and ion impact energy at the cylindrical inner surface, as well as the ion energy distribution, maximum ion impact energy, and average ion impact energy for the various cases are obtained. Our results show a dramatic improvement in the impact energy when an auxiliary electrode is used and the recommended normalized auxiliary electrode radius is in the range of 0.1 endash 0.3. copyright 1998 American Institute of Physics

On the Interaction between a Tunnel Boring Machine and the Surrounding Soil

NARCIS (Netherlands)

Festa, D.

2015-01-01

The thesis investigates the mechanical equilibrium of a Tunnel Boring Machine (TBM) driving in soft soil. The interaction between the TBM-shield and the soil is also investigated. The analysis is based on monitoring data gathered during the construction of the Hubertus tunnel in The Hague,

Neutrino constraints that transform black holes into grey holes

International Nuclear Information System (INIS)

Ruderfer, M.

1982-01-01

Existing black hole theory is found to be defective in its neglect of the physical properties of matter and radiation at superhigh densities. Nongravitational neutrino effects are shown to be physically relevant to the evolution of astronomical black holes and their equations of state. Gravitational collapse to supernovae combined with the Davis and Ray vacuum solution for neutrinos limit attainment of a singularity and require black holes to evolve into ''grey holes''. These allow a better justification than do black holes for explaining the unique existence of galactic masses. (Auth.)

Experimental Study on Post Grouting Bearing Capacity of Large Diameter Bored Piles

Directory of Open Access Journals (Sweden)

Wang Duanduan

2015-01-01

Full Text Available Post grouting can improve the inherent defects such as the formation of the mud cake at pile side and the sediment at pile end in the process of bored pile construction. Thus post grouting has been widely used in Engineering. The purpose of this paper is to research the influences of post grouting to pile bearing capacity more systematically and intuitively. Combined with the static load test of four test piles in Weihe River Bridge test area of new airport highway in Xi’an, the bearing capacity and settlement of routine piles and post grouting piles are comparatively analyzed. The test results show that under the same geological condition, post grouting can improve the properties of pile tip and pile shaft soil of bored piles significantly, enhance the ultimate resistance, improve the ultimate bearing capacity and reduce the pile tip settlement. Then post grouting can aim to optimize pile foundation.

Outcome of ultrasound-guided small-bore catheter drainage in exudative pleural effusions.

Science.gov (United States)

Kiranantawat, Nantaka; Sungsiri, Jitpreedee; Geater, Sarayut L

2014-05-01

To evaluate the outcome and safety of ultrasound-guided percutaneous catheter drainage of exudative pleural effusion. The present study was a retrospective analysis of 412 pleural effusions from 373 patients that underwent ultrasound-guided small-bore catheter drainage in exudative pleural effusions between 2004 and 2009. The two most common causes for drainage were parapneumonic effusion or empyema (52.2%) and malignant effusion (30.3%), while the remains were trauma, iatrogenic, and others. Overall clinical success rate was 76.5%. The success rate was lower among malignant pleural effusion (p = 0.003). Causes of effusion were the only independent predictors related to success. Only five (1.2%) patients developed complication during the procedure. Seventy-five of 412 effusions (15.8%) developed complication during the period of drainage; the majority were drain blockage (9%) and accidental dislodgment (4.1%). Ultrasound-guided small-bore catheter drainage was a safe and efficient procedure for exudative pleural effusions.

Determination of bore efficiency loss employed as powder in boral fabrication, proportionately to the dimension of grain; Determination de la reduction d'efficacite du bore ou d'un autre absorbeur employe sous forme de poudre dissemine dans un produit non absorbant, en fonction de la grosseur des grains

Energy Technology Data Exchange (ETDEWEB)

Laforge, P; Millot, J P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1957-07-01

Authors' mind was attracted by the importance of bore granulometry when employed as powder in boral fabrication. The calculation, object of this report, permits to give values for bore efficiency loss, proportionately to the dimension of spherical or ellipsoidal supposed grains. Grains to be employed should exceptionally only exceed 20 {mu} for a correspondent efficiency loss of 8 per cent about. (author) [French] L'attention des auteurs a ete attiree sur l'importance de la granulometrie du bore employe sous forme de poudre dans la fabrication du boral. Le calcul qui fait l'objet de ce rapport permet de chiffrer la perte d'efficacite du bore en fonction de la dimension des grains supposes spheriques ou ellipsoidaux. Les grains a employer ne devraient qu'exceptionnellement etre superieurs a 20 microns, ce qui correspond a une perte d'efficacite d'environ 8 pour cent. (auteur)

Evidence of cellulose digestion in the wood boring isopod Sphaeroma terebrans

Science.gov (United States)

Lori K. Benson; Stanley A. Rice; Bruce R. Johnson

1999-01-01

Sphaeroma terebrans Bate is a widespread estuarine, wood-boring, isopod found in red mangrove (Rhizophora mangle) forests of tropical and subtropical estuarine waters. Because it causes extensive damage to man-made structures in marine coastal zones and is resistant to common methods of wood preservation it is important to understand fully how S. terebrans uses the...

Seismic damping factors of small-bore piping as influenced by insulation and support elements

International Nuclear Information System (INIS)

Severud, L.K.; Anderson, M.J.; Barta, D.A.

1983-01-01

Seismic damping tests of a prototypical Liquid Metal Fast Breeder Reactor (LMFBR) small-bore piping system is described, and measured transient responses to pulse excitations are reported. The test specimen was representative of a typical LMFBR insulated small-bore piping system, and it was supported from a rigid test fame by prototypic dead-weight supports, mechanical snubbers, and pipe clamps. Various support configurations were tested to assess the reponse sensitivity to insulation and use of mechanical snubbers. Factors much higher than the magnitudes currently allowed in design, by the USNRC Regulatory Guide 1.61, were found. This verified the design values but also pointed out the possibility of undue conservatism and costly overdesign resulting from use of the present design values

A geostatistical estimation of zinc grade in bore-core samples

International Nuclear Information System (INIS)

Starzec, A.

1987-01-01

Possibilities and preliminary results of geostatistical interpretation of the XRF determination of zinc in bore-core samples are considered. For the spherical model of the variogram the estimation variance of grade in a disk-shape sample (estimated from the grade on the circumference sample) is calculated. Variograms of zinc grade in core samples are presented and examples of the grade estimation are discussed. 4 refs., 7 figs., 1 tab. (author)

Maintaining Masculinity in Mid-Twentieth-Century American Psychology: Edwin Boring, Scientific Eminence, and the "Woman Problem".

Science.gov (United States)

Rutherford, Alexandra

2015-01-01

Using mid-twentieth-century American psychology as my focus, I explore how scientific psychology was constructed as a distinctly masculine enterprise and was navigated by those who did not conform easily to this masculine ideal. I show how women emerged as problems for science through the vigorous gatekeeping activities and personal and professional writings of disciplinary figurehead Edwin G. Boring. I trace Boring's intellectual and professional socialization into masculine science and his efforts to understand women's apparent lack of scientific eminence, efforts that were clearly undergirded by preexisting and widely shared assumptions about men's and women's capacities and preferences.

Primary black holes

International Nuclear Information System (INIS)

Novikov, I.; Polnarev, A.

1981-01-01

Proves are searched for of the formation of the so-called primary black holes at the very origin of the universe. The black holes would weigh less than 10 13 kg. The formation of a primary black hole is conditional on strong fluctuations of the gravitational field corresponding roughly to a half of the fluctuation maximally permissible by the general relativity theory. Only big fluctuations of the gravitational field can overcome the forces of the hot gas pressure and compress the originally expanding matter into a black hole. Low-mass black holes have a temperature exceeding that of the black holes formed from stars. A quantum process of particle formation, the so-called evaporation takes place in the strong gravitational field of a black hole. The lower the mass of the black hole, the shorter the evaporation time. The analyses of processes taking place during the evaporation of low-mass primary black holes show that only a very small proportion of the total mass of the matter in the universe could turn into primary black holes. (M.D.)

Application of streaming potential method for detection of fractures in granitic rock; Kamaishi kozan ni okeru ryutai ryudo den`iho tekiyo shiken

Energy Technology Data Exchange (ETDEWEB)

Negi, T; Yokoi, K; Yoneda, Y [Nittetsu Mining Co. Ltd., Tokyo (Japan); Senba, T [Power Reactor and Nuclear fuel Development Corporation, Tokyo (Japan)

1996-05-01

Measurements were made using the streaming potential method for the purpose of investigating the expansion of hydration cracks, direction of their propagation, and the chaining of cracked surfaces, in the granitic rock. Tests were conducted by use of a bore hole in the gallery wall. The bore hole yielded approximately 400 liters of water per minute, the bore hole was closed and then opened, and the change with the passage of time in the spontaneous potential (SP) on the gallery wall was measured. At a spot 31.2m from the mine entrance, the SP dropped by 15mV simultaneously with the opening of the bore hole, and rose by 14mV simultaneously with the closure of the same. The phenomenon was true for other locations, that is, for the section from the mine entrance to a spot 9.0m therefrom, and for a section beginning at 15.0m and ending at 19.2m therefrom. No change in the SP was observed in a group of cracks with water springing out of the gallery roof, beginning at a point 40m and ending at a point 54m from the mine entrance. The result suggests the possible application of the streaming potential method to the investigation of cracks. 1 ref., 10 figs.

From binary black hole simulation to triple black hole simulation

International Nuclear Information System (INIS)

Bai Shan; Cao Zhoujian; Han, Wen-Biao; Lin, Chun-Yu; Yo, Hwei-Jang; Yu, Jui-Ping

2011-01-01

Black hole systems are among the most promising sources for a gravitational wave detection project. Now, China is planning to construct a space-based laser interferometric detector as a follow-on mission of LISA in the near future. Aiming to provide some theoretical support to this detection project on the numerical relativity side, we focus on black hole systems simulation in this work. Considering the globular galaxy, multiple black hole systems also likely to exist in our universe and play a role as a source for the gravitational wave detector we are considering. We will give a progress report in this paper on our black hole system simulation. More specifically, we will present triple black hole simulation together with binary black hole simulation. On triple black hole simulations, one novel perturbational method is proposed.

Phase transition for black holes with scalar hair and topological black holes

International Nuclear Information System (INIS)

Myung, Yun Soo

2008-01-01

We study phase transitions between black holes with scalar hair and topological black holes in asymptotically anti-de Sitter spacetimes. As the ground state solutions, we introduce the non-rotating BTZ black hole in three dimensions and topological black hole with hyperbolic horizon in four dimensions. For the temperature matching only, we show that the phase transition between black hole with scalar hair (Martinez-Troncoso-Zanelli black hole) and topological black hole is second-order by using differences between two free energies. However, we do not identify what order of the phase transition between scalar and non-rotating BTZ black holes occurs in three dimensions, although there exists a possible decay of scalar black hole to non-rotating BTZ black hole

The Boring Billion, a slingshot for Complex Life on Earth.

Science.gov (United States)

Mukherjee, Indrani; Large, Ross R; Corkrey, Ross; Danyushevsky, Leonid V

2018-03-13

The period 1800 to 800 Ma ("Boring Billion") is believed to mark a delay in the evolution of complex life, primarily due to low levels of oxygen in the atmosphere. Earlier studies highlight the remarkably flat C, Cr isotopes and low trace element trends during the so-called stasis, caused by prolonged nutrient, climatic, atmospheric and tectonic stability. In contrast, we suggest a first-order variability of bio-essential trace element availability in the oceans by combining systematic sampling of the Proterozoic rock record with sensitive geochemical analyses of marine pyrite by LA-ICP-MS technique. We also recall that several critical biological evolutionary events, such as the appearance of eukaryotes, origin of multicellularity & sexual reproduction, and the first major diversification of eukaryotes (crown group) occurred during this period. Therefore, it appears possible that the period of low nutrient trace elements (1800-1400 Ma) caused evolutionary pressures which became an essential trigger for promoting biological innovations in the eukaryotic domain. Later periods of stress-free conditions, with relatively high nutrient trace element concentration, facilitated diversification. We propose that the "Boring Billion" was a period of sequential stepwise evolution and diversification of complex eukaryotes, triggering evolutionary pathways that made possible the later rise of micro-metazoans and their macroscopic counterparts.

Black Holes

OpenAIRE

Townsend, P. K.

1997-01-01

This paper is concerned with several not-quantum aspects of black holes, with emphasis on theoretical and mathematical issues related to numerical modeling of black hole space-times. Part of the material has a review character, but some new results or proposals are also presented. We review the experimental evidence for existence of black holes. We propose a definition of black hole region for any theory governed by a symmetric hyperbolic system of equations. Our definition reproduces the usu...

Interaction between groundwater and TBM (Tunnel Boring Machine) excavated tunnels

OpenAIRE

Font Capó, Jordi

2012-01-01

A number of problems, e.g. sudden inflows are encountered during tunneling under the piezometric level, especially when the excavation crosses high transmissivity areas. These inflows may drag materials when the tunnel crosses low competent layers, resulting in subsidence, chimney formation and collapses. Moreover, inflows can lead to a decrease in head level because of aquifer drainage. Tunnels can be drilled by a tunnel boring machine (TBM) to minimize inflows and groundwater impacts, restr...

Seismic damping factors of small bore piping as influenced by insulation and support elements

International Nuclear Information System (INIS)

Severud, L.K.; Anderson, M.J.; Barta, D.A.

1985-01-01

Seismic damping tests of a prototypical Liquid Metal Fast Breeder Reactor (LMFBR) small bore piping system is described, and measured transient responses to pulse excitations are reported. The test specimen was representative of a typical LMFBR insulated small bore piping system, and it was supported from a rigid test frame by prototypic dead weight supports, mechanical snubbers, and pipe clamps. Various support configurations were tested to assess the response sensitivity to insulation and other nonlinear support characteristics. Damping factors increased significantly due to the insulation and use of mechanical snubbers. Factors much higher than the magnitudes currently allowed in design by the USNRC Regulatory Guide 1.61, were found. This verified the design values, and it also pointed out the possibility of undue conservatism and costly overdesign resulting from use of the present design values

Seismic damping factors of small bore piping as influenced by insulation and support elements

International Nuclear Information System (INIS)

Severud, L.K.; Barta, D.A.

1983-01-01

Seismic damping tests of a prototypical Liquid Metal Fast Breeder Reactor (LMFBR) small bore piping system is described, and measured transient responses to pulse excitations are reported. The test specimen was representative of a typical LMFBR insulated small bore piping system, and it was supported from a rigid test frame by prototypic dead weight supports, mechanical snubbers, and pipe clamps. Various support configurations were tested to assess the response sensitivity to insulation and other nonlinear support characteristics. Damping factors increased significantly due to the insulation and use of mechanical snubbers. Factors much higher than the magnitudes currently allowed in design, by the USNRC Regulatory Guide 1.61, were found. This verified the design values but also pointed out the possibility of undue conservatism and costly overdesign resulting from use of the present design values

Borehole imaging tool detects well bore fractures

International Nuclear Information System (INIS)

Ma, T.A.; Bigelow, E.L.

1993-01-01

This paper reports on borehole imaging data which can provide high quality geological and petrophysical information to improve fracture identification, dip computations, and lithology determinations in a well bore. The ability to visually quantify the area of a borehole wall occupied by fractures and vugs enhances reservoir characterization and well completion operations. The circumferential borehole imaging log (CBIL) instrument is an acoustic logging device designed to produce a map of the entire borehole wall. The visual images can confirm computed dips and the geological features related to dip. Borehole geometry, including breakout, are accurately described by complete circumferential caliper measurements, which is important information for drilling and completion engineers. In may reservoirs, the images can identify porosity type, bedding characteristics, and petrophysical parameters

Low-mass black holes as the remnants of primordial black hole formation.

Science.gov (United States)

Greene, Jenny E

2012-01-01

Bridging the gap between the approximately ten solar mass 'stellar mass' black holes and the 'supermassive' black holes of millions to billions of solar masses are the elusive 'intermediate-mass' black holes. Their discovery is key to understanding whether supermassive black holes can grow from stellar-mass black holes or whether a more exotic process accelerated their growth soon after the Big Bang. Currently, tentative evidence suggests that the progenitors of supermassive black holes were formed as ∼10(4)-10(5) M(⊙) black holes via the direct collapse of gas. Ongoing searches for intermediate-mass black holes at galaxy centres will help shed light on this formation mechanism.

TMI-2 core boring machine

International Nuclear Information System (INIS)

Croft, K.M.; Helbert, H.J.; Laney, W.M.

1986-01-01

An important and essential aspect of the TMI-2 defueling effort is to determine what occurred in the core region during the accident. Remote cameras and probes only portray a portion of the overall picture. What lies beneath the rubble bed and solidified sublayer is, as yet, unknown. This paper discusses the TMI-2 Core Boring Machine, which has been developed to drill into the damaged core of the TMI-2 reactor and extract stratified samples of the core. This machine, its unique support structure, positioning and leveling systems, and specially designed drill bits, combine to provide a unique mechanical system. In addition, the machine is controlled by a microprocessor; which actually controls the drilling operation, allowing relatively inexperienced operators to drill the core samples. A data acquisition system is data integral with the controlling system and collects data relative to system conditions and monitored parameters during drilling. Data obtained during the actual drilling operations are collected in a data base which will be used for actual mapping of the core region, identifying materials and stratification levels that are present

Tunnel boring waste test plan

International Nuclear Information System (INIS)

Patricio, J.G.

1984-03-01

The test plan has been prepared in anticipation of the need to excavate certain repository openings by relying upon mechanical excavation techniques. The test plan proposes that specific technical issues can be resolved and key design parameters defined by excavating openings in basalt near the surface, utilizing a full face tunnel boring machine (TBM). The purpose and objective of this type of testing will define the overall feasibility and attributes of mechanical excavation in basalt. The test plan recognizes that although this technology is generally available for underground construction for some geologic settings, the current state of technology for excavation in basalt is limited and the potential for improvement is considerable. The test plan recommends that it is economically advantageous to conduct additional testing in the laboratory to allow refinement of this plan based on the laboratory results. Thus, this test plan is considered preliminary in nature, with respect to detailed testing recommendations. However, the gross design attributes and resource requirements of a near-surface TBM demonstration are considered to be valid. 15 refs., 7 figs., 3 tabs

Better well control through safe drilling margin identification, influx analysis and direct bottom hole pressure control method for deep water

Energy Technology Data Exchange (ETDEWEB)

Veeningen, Daan [National Oilwell Varco IntelliServ (NOV), Houston, TX (United States)

2012-07-01

Currently, well control events are almost exclusively detected by using surface measurements. Measuring a volume increase in the 'closed loop' mud circulation system; a standpipe pressure decrease; or changes in a variety of drilling parameters provide indicators of a kick. Especially in deep water, where the riser comprises a substantial section of the well bore, early kick detection is paramount for limiting the severity of a well bore influx and improve the ability to regain well control. While downhole data is presently available from downhole tools nearby the bit, available data rates are sparse as mud pulse telemetry bandwidth is limited and well bore measurements compete with transmission of other subsurface data. Further, data transfer is one-directional, latency is significant and conditions along the string are unknown. High-bandwidth downhole data transmission system, via a wired or networked drill string system, has the unique capability to acquire real-time pressure and temperature measurement at a number of locations along the drill string. This system provides high-resolution downhole data available at very high speed, eliminating latency and restrictions that typically limit the availability of downhole data. The paper describes well control opportunities for deep water operations through the use of downhole data independent from surface measurements. First, the networked drill string provides efficient ways to identify pore pressure, fracture gradient, and true mud weight that comprise the safe drilling margin. Second, the independent measurement capability provides early kick detection and improved ability to analyze an influx even with a heterogeneous mud column through distributed along-string annular pressure measurements. Third, a methodology is proposed for a direct measurement method using downhole real-time pressure for maintaining constant bottom hole pressure during well kills in deep water. (author)

Generic methods for design of small-bore pipe supports

International Nuclear Information System (INIS)

Clark, G.L.; LaSalle, F.R.

1981-01-01

Large numbers of supports for small-bore, low-temperature pipe are utilized in nuclear power plants. These supports often must meet ASME code and project seismic design requirements. Detailed analysis for each support is time consuming and costly. This paper describes some economical generic methods developed to design and qualify supports for two-inch and smaller pipe operating at temperatures less than 300 0 F (185 0 C), on the Fast Flux Test Facility. Use of standard designs, standard support spacing tables, anchor bolt and baseplate considerations, and field qualification methods are discussed

Hole dephasing caused by hole-hole interaction in a multilayered black phosphorus.

Science.gov (United States)

Li, Lijun; Khan, Muhammad Atif; Lee, Yoontae; Lee, Inyeal; Yun, Sun Jin; Youn, Doo-Hyeb; Kim, Gil-Ho

2017-11-01

We study the magnetotransport of holes in a multilayered black phosphorus in a temperature range of 1.9 to 21.5 K. We observed a negative magnetoresistance at magnetic fields up to 1.5 T. This negative magetoresistance was analyzed by weak localization theory in diffusive regime. At the lowest temperature and the highest carrier density we found a phase coherence length of 48 nm. The linear temperature dependence of the dephasing rate shows that the hole-hole scattering processes with small energy transfer are the dominant contribution in breaking the carrier phase coherence.

Customer Overview of Pulsed Laser Heating for Evaluation of Gun Bore Materials

Science.gov (United States)

2015-05-01

properties of the gun bore materials. Ideally, well validated interior ballistics modeling has been carried out (typically with NOVA) to provide time...03002, February 2003. 5. J. Warrender, C. Mulligan, and J. Underwood , “Analysis of thermo-mechanical cracking in refractory coatings using variable pulse duration laser pulse heating,” Wear 263 1540 (2007).

Measurement of in-bore side loads and comparison to first maximum yaw

Directory of Open Access Journals (Sweden)

Donald E. Carlucci

2016-04-01

Full Text Available In-bore yaw of a projectile in a gun tube has been shown to result in range loss if the yaw is significant. An attempt was made to determine if relationships between in-bore yaw and projectile First Maximum Yaw (FMY were observable. Experiments were conducted in which pressure transducers were mounted near the muzzle of a 155 mm cannon in three sets of four. Each set formed a cruciform pattern to obtain a differential pressure across the projectile. These data were then integrated to form a picture of what the overall pressure distribution was along the side of the projectile. The pressure distribution was used to determine a magnitude and direction of the overturning moment acting on the projectile. This moment and its resulting angular acceleration were then compared to the actual first maximum yaw observed in the test. The degree of correlation was examined using various statistical techniques. Overall uncertainty in the projectile dynamics was between 20% and 40% of the mean values of FMY.

Enhanced Automated Guidance System for Horizontal Auger Boring Based on Image Processing.

Science.gov (United States)

Wu, Lingling; Wen, Guojun; Wang, Yudan; Huang, Lei; Zhou, Jiang

2018-02-15

Horizontal auger boring (HAB) is a widely used trenchless technology for the high-accuracy installation of gravity or pressure pipelines on line and grade. Differing from other pipeline installations, HAB requires a more precise and automated guidance system for use in a practical project. This paper proposes an economic and enhanced automated optical guidance system, based on optimization research of light-emitting diode (LED) light target and five automated image processing bore-path deviation algorithms. An LED light target was optimized for many qualities, including light color, filter plate color, luminous intensity, and LED layout. The image preprocessing algorithm, direction location algorithm, angle measurement algorithm, deflection detection algorithm, and auto-focus algorithm, compiled in MATLAB, are used to automate image processing for deflection computing and judging. After multiple indoor experiments, this guidance system is applied in a project of hot water pipeline installation, with accuracy controlled within 2 mm in 48-m distance, providing accurate line and grade controls and verifying the feasibility and reliability of the guidance system.

Primary Signet Ring Cell Carcinoma of Rectum Diagnosed by Boring Biopsy in Combination with Endoscopic Mucosal Resection

Directory of Open Access Journals (Sweden)

Yoshito Hirata

2018-01-01

Full Text Available A 46-year-old man with severe back pain visited our hospital. Magnetic resonance imaging revealed extensive bone metastasis and rectal wall thickness. Colonoscopy revealed circumferential stenosis with edematous mucosa, suggesting colon cancer. However, histological findings of biopsy specimens revealed inflammatory cells but no malignant cells. The patient underwent endoscopic ultrasound, which demonstrated edematous wall thickness without destruction of the normal layer structure. After unsuccessful detection of neoplastic cells by boring biopsies, we performed endoscopic mucosal resection followed by boring biopsies that finally revealed signet ring cell carcinoma. Herein, we present a case and provide a review of the literature.

Bifurcation from stable holes to replicating holes in vibrated dense suspensions.

Science.gov (United States)

Ebata, H; Sano, M

2013-11-01

In vertically vibrated starch suspensions, we observe bifurcations from stable holes to replicating holes. Above a certain acceleration, finite-amplitude deformations of the vibrated surface continue to grow until void penetrates fluid layers, and a hole forms. We studied experimentally and theoretically the parameter dependence of the holes and their stabilities. In suspensions of small dispersed particles, the circular shapes of the holes are stable. However, we find that larger particles or lower surface tension of water destabilize the circular shapes; this indicates the importance of capillary forces acting on the dispersed particles. Around the critical acceleration for bifurcation, holes show intermittent large deformations as a precursor to hole replication. We applied a phenomenological model for deformable domains, which is used in reaction-diffusion systems. The model can explain the basic dynamics of the holes, such as intermittent behavior, probability distribution functions of deformation, and time intervals of replication. Results from the phenomenological model match the linear growth rate below criticality that was estimated from experimental data.

Mercury as a proxy for volcanic activity during extreme environmental turnover

DEFF Research Database (Denmark)

Sial, A.N.; Lacerda, L.D.; Ferreira, V.P.

2013-01-01

(KTB) and was, perhaps, responsible for dramatic climatic changes and decrease in biodiversity and mass extinction. We have used Hg concentrations as a proxy for volcanic activity and atmospheric Hg and CO2 buildup across the KTB at three localities. In the Salta Basin, Argentina, Hg contents display...... close to) this transition. At Stevns Klint, Denmark, Hg contents reached almost 250 ng·g− 1 within a 5 cm thick-clay layer, the Fiskeler Member (‘Fish Clay’) that comprises the KTB. Some co-variation between Hg and Al2O3 contents has been observed in all of the studied sections across the KTB......, suggesting that Hg is probably adsorbed onto clays. Thermo-desorption experiments in selected samples from the Yacoraite Formation showed Hg+ 2 as the major species present, which is in agreement with a volcanic origin. Combined Hg and C-isotope chemostratigraphy may become a powerful tool for the eventual...

Influence of ethanol as bore fluid component on the morphological structure and performance of PES hollow fiber membrane for oil in water separation

Energy Technology Data Exchange (ETDEWEB)

Otitoju, Tunmise Ayode; Ahmad, Abdul Latif; Ooi, Boon Seng [Universiti Sains Malaysia, Penang (Malaysia)

2017-10-15

The relationships among varying bore fluid compositions containing ethanol/water were studied. The ethanol composition was varied in the ratio of 0%, 25%, 50%, 75% and 100%. The membrane dope solutions were prepared from 17.25 wt% polyethersulfone (PES), 0.75 wt% polyethylene glycol (PEG), 3 wt% silicon dioxide sol and 78.25 wt% of 1-methyl-2-pyrrolidone (NMP) via dry-jet spinning process. The membranes’ morphology as a result of varying ethanol ratio in the bore fluid composition was characterized and their effects on crude oil/water emulsion separation were evaluated. Results show that the membrane pore size and porosity decreased with increasing ethanol content in the bore fluid mixture, whereas the inner wall thickness of fibers increased. Furthermore, an increase in ethanol concentration also resulted in a slight increase in water contact angle. The use of 100/0 of ethanol/water resulted in UF membranes with the lowest performance. On the other hand, bore fluid mixture containing 25/75 ethanol/water produced membrane with the best performance for crude oil/water separation. Overall, the use of bore fluid mixture containing 25/75 ethanol/water mixture was found to be a powerful way to tune the morphological properties and performance of HF membrane.

Influence of ethanol as bore fluid component on the morphological structure and performance of PES hollow fiber membrane for oil in water separation

International Nuclear Information System (INIS)

Otitoju, Tunmise Ayode; Ahmad, Abdul Latif; Ooi, Boon Seng

2017-01-01

The relationships among varying bore fluid compositions containing ethanol/water were studied. The ethanol composition was varied in the ratio of 0%, 25%, 50%, 75% and 100%. The membrane dope solutions were prepared from 17.25 wt% polyethersulfone (PES), 0.75 wt% polyethylene glycol (PEG), 3 wt% silicon dioxide sol and 78.25 wt% of 1-methyl-2-pyrrolidone (NMP) via dry-jet spinning process. The membranes’ morphology as a result of varying ethanol ratio in the bore fluid composition was characterized and their effects on crude oil/water emulsion separation were evaluated. Results show that the membrane pore size and porosity decreased with increasing ethanol content in the bore fluid mixture, whereas the inner wall thickness of fibers increased. Furthermore, an increase in ethanol concentration also resulted in a slight increase in water contact angle. The use of 100/0 of ethanol/water resulted in UF membranes with the lowest performance. On the other hand, bore fluid mixture containing 25/75 ethanol/water produced membrane with the best performance for crude oil/water separation. Overall, the use of bore fluid mixture containing 25/75 ethanol/water mixture was found to be a powerful way to tune the morphological properties and performance of HF membrane.

Optical probe for porosity defect detection on inner diameter surfaces of machined bores

Science.gov (United States)

Kulkarni, Ojas P.; Islam, Mohammed N.; Terry, Fred L.

2010-12-01

We demonstrate an optical probe for detection of porosity inside spool bores of a transmission valve body with diameters down to 5 mm. The probe consists of a graded-index relay rod that focuses a laser beam spot onto the inner surface of the bore. Detectors, placed in the specular and grazing directions with respect to the incident beam, measure the change in scattered intensity when a surface defect is encountered. Based on the scattering signatures in the two directions, the system can also validate the depth of the defect and distinguish porosity from bump-type defects coming out of the metal surface. The system can detect porosity down to a 50-μm lateral dimension and ~40 μm in depth with >3-dB contrast over the background intensity fluctuations. Porosity detection systems currently use manual inspection techniques on the plant floor, and the demonstrated probe provides a noncontact technique that can help automotive manufacturers meet high-quality standards during production.

Construction of a cylindrical brine test room using a tunnel boring machine

International Nuclear Information System (INIS)

Likar, V.F.; Burrington, T.P.

1990-01-01

This paper discusses the construction of a horizontal cylindrical brine test room at the Waste Isolation Pilot Plant (WIPP). The room was constructed in the bedded salt formation at a depth of 655 meters with a tunnel boring machine. The machine leasing technical and operational management, parameters involved, and successful completion of this effort are included. 3 figs

Construction of a cylindrical brine test room using a tunnel boring machine

International Nuclear Information System (INIS)

Likar, V.F.; Burrington, T.P.

1990-01-01

This paper discusses the construction of a horizontal cylindrical brine test room at the Waste Isolation Pilot Plant (WIPP). The room was constructed in the bedded salt formation at a depth of 655 meters with a tunnel boring machine. The machine leasing, technical and operational management, parameters involved, and successful completion of this effort are included. 3 figs

Analysis and separation of boron isotopes; Analyse et separation des isotopes du bore

Energy Technology Data Exchange (ETDEWEB)

Perie, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1966-11-01

The nuclear applications of boron-10 justify the study of a method of measurement of its isotopic abundance as well as of very small traces of boron in different materials. A systematic study of thermionic emission of BO{sub 2}Na{sub 2}{sup +} has been carried out. In the presence of a slight excess of alkalis, the thermionic emission is considerably reduced. On the other hand, the addition of a mixture of sodium hydroxide-glycerol (or mannitol) to borax permits to obtain an intense and stable beam. These results have permitted to establish an operative method for the analysis of traces of boron by isotopic dilution. In other respects, the needs of boron-10 in nuclear industry Justify the study of procedures of separation of isotopes of boron. A considerable isotopic effect has been exhibited in the chemical exchange reaction between methyl borate and borate salt in solution. In the case of exchange between methyl borate and sodium borate, the elementary separation factor {alpha} is: {alpha}=(({sup 11}B/{sup 10}B)vap.)/(({sup 11}B/{sup 10}B)liq.)=1.03{sub 3}. The high value of this elementary effect has been multiplied in a distillation column in which the problem of regeneration of the reactive has been resolved. An alternative procedure replacing the alkali borate by a borate of volatile base, for example diethylamine, has also been studied ({alpha}=1,02{sub 5} in medium hydro-methanolic with 2,2 per cent water). (author) [French] Les applications nucleaires du bore 10 justifient l'etude d'une methode de mesure de son abondance isotopique dans divers materiaux ainsi que le dosage de tres faibles traces de bore. Une etude systematique de l'emission thermoionique de BO{sub 2} Na{sub 2}{sup +} a ete effectuee. En presence d'un leger exces d'alcalins, l'emission thermoionique est considerablement reduite. Par contre l'addition au borax d'un melange soude-glycerol (ou mannitol) permet d'obtenir un faisceau stable et intense. Ces resultats ont permis d'etablir un mode

Seismic monitoring experiment of raise boring in 2014

International Nuclear Information System (INIS)

Saari, J.; Malm, M.

2015-01-01

In Olkiluoto, Posiva Oy has operated a local seismic network since February 2002. The purpose of the microearthquake measurements at Olkiluoto is to improve understanding of the structure, behaviour and long term stability of the bedrock. The studies include both tectonic and excavation-induced microearthquakes. An additional task of monitoring is related to safeguarding of ONKALO. The possibility to excavate an illegal access to ONKALO has been concerned when the safeguards are discussed. Therefore all recorded explosions in the Olkiluoto area and in ONKALO are located. If a concentration of explosions is observed, the origin of that is found out. Also a concept of hidden illegal explosions, detonated at the same time as the real excavation blasts, has been examined. According to the experience gained in Olkiluoto, it can be concluded that, as long the seismic network is in operation and the results are analysed by a skilled person, it is practically impossible to do illegal undetected excavation by blasting within the Olkiluoto seismic network area. In this report a possibility of seismic monitoring of undeclared excavation done by tunnel boring machine (TBM) has been investigated. In the earlier investigations the instruments were at the ground surface and the sensors were triaxial short period (1 Hz) geophones or broadband geophones. The characteristics (frequency content, polarity and amplitude) of the continuous seismic vibration generated by TMB were studied. The onset time of the seismic signal were not distinguished. Altogether 16 new 10 kHz accelerometers were installed in boreholes inside ONKALO March 2012. The sensors comprised a new subnetwork that monitored the raise boring of two shafts done 2014, from the level -455 m to the level -290 m. The aim was to record the seismic signal generated when the drill bit hits the rock at the moment the tunnel boring begins. Altogether 113 seismic signals generated by the drill bit were located during the

Seismic monitoring experiment of raise boring in 2014

Energy Technology Data Exchange (ETDEWEB)

Saari, J.; Malm, M. [AaF-Consult Oy, Espoo (Finland)

2015-01-15

In Olkiluoto, Posiva Oy has operated a local seismic network since February 2002. The purpose of the microearthquake measurements at Olkiluoto is to improve understanding of the structure, behaviour and long term stability of the bedrock. The studies include both tectonic and excavation-induced microearthquakes. An additional task of monitoring is related to safeguarding of ONKALO. The possibility to excavate an illegal access to ONKALO has been concerned when the safeguards are discussed. Therefore all recorded explosions in the Olkiluoto area and in ONKALO are located. If a concentration of explosions is observed, the origin of that is found out. Also a concept of hidden illegal explosions, detonated at the same time as the real excavation blasts, has been examined. According to the experience gained in Olkiluoto, it can be concluded that, as long the seismic network is in operation and the results are analysed by a skilled person, it is practically impossible to do illegal undetected excavation by blasting within the Olkiluoto seismic network area. In this report a possibility of seismic monitoring of undeclared excavation done by tunnel boring machine (TBM) has been investigated. In the earlier investigations the instruments were at the ground surface and the sensors were triaxial short period (1 Hz) geophones or broadband geophones. The characteristics (frequency content, polarity and amplitude) of the continuous seismic vibration generated by TMB were studied. The onset time of the seismic signal were not distinguished. Altogether 16 new 10 kHz accelerometers were installed in boreholes inside ONKALO March 2012. The sensors comprised a new subnetwork that monitored the raise boring of two shafts done 2014, from the level -455 m to the level -290 m. The aim was to record the seismic signal generated when the drill bit hits the rock at the moment the tunnel boring begins. Altogether 113 seismic signals generated by the drill bit were located during the

Cataclastic effects in rock salt laboratory and in situ measurements

International Nuclear Information System (INIS)

Gramberg, J.; Roest, J.P.A.

1984-01-01

The aim of the research is the determination of eventual cataclastic effects in environmental rock salt of a heated part of a vertical deep test bore hole, a model for HLW disposal. Known cataclastic systems from hard rock mining and rock salt mines will form the starting point for the explanation of convergence of underground cavity walls. In rock salt, however, different elements seem to prevail: crystal plasticity and micro-cataclasis. The environmental measurements at the deep bore hole have to be carried out from a distance. To this end the acoustic micro-seismic method will be a suitable one. The appropriate equipment for micro-seismic cross hole measurement is designed, constructed and tested in the laboratory as well as underground. Acoustic velocity data form a crucial point. A micro-seismic acoustic P-wave model, adapted to the process of structural changes, is developed. P-wave velocity measurements in rock salt cubes in the laboratory are described. An underground cross hole measurement in the wall of a gallery with semi-circular section is treated and analysed. A conclusion was that, in this case, no macro-cataclasis (systematic large fractures) will be involved in the process of gallery convergence, but that the mechanism proved to be a combination of crystal plasticity and micro-cataclasis. The same mechanism might be expected to be present in the environmental rock salt of the HLW-disposal deep bore hole. As a result this environmental rock salt might be expected to be impermeable. A plan for the application of the developed equipment during the heating test on the ECN-deep-bore-hole is shown. A theory on ''disking'' or ''rim cracks'' is presented in an annex

A Dual Operational Refrigerator/Flow Cryostat with Wide Bore Medium Field Magnet for Application Demonstration

Science.gov (United States)

Young, E. A.; Bailey, W. O. S.; Al-Mosawi, M. K.; Beduz, C.; Yang, Y.; Chappell, S.; Twin, A.

Since stand alone cryocooler systems have become more widely available, there has been increased commercial interest in superconductor applications in the temperature range intermediate to liquid helium and liquid nitrogen. There are however few facilities that have large in-field bore size with variable temperatures. A large bore system can reduce costs associated with full scale demonstration magnets by testing smaller coils and qualify medium length (up to meters) conductors. A 5 T, wide bore, (170 mm) Nb3Sn Oxford Instrument magnet has been integrated into a custom built dual mode refrigerator/helium flow cryostat with 600A HTS current leads. In one mode the system can be used with zero field without cost of liquid helium relying for cooling on a Sumitomo GM cryocooler with 1.5W at 4.2K: (no He) this can be used either as the sole characterisation method, or as a preliminary check before more expensive and extensive measurements are taken. The first measurements using MgB2 wire from 10 to 20K were made using a transient current step of ∼5s duration, as opposed to a DC measurement. This has the advantage of not requiring thermal equilibrium to be achieved at nominal current. The feasibility of this technique for determining critical transport properties is discussed.

Respiratory-Gated MRgHIFU in Upper Abdomen Using an MR-Compatible In-Bore Digital Camera

Directory of Open Access Journals (Sweden)

Vincent Auboiroux

2014-01-01

Full Text Available Objective. To demonstrate the technical feasibility and the potential interest of using a digital optical camera inside the MR magnet bore for monitoring the breathing cycle and subsequently gating the PRFS MR thermometry, MR-ARFI measurement, and MRgHIFU sonication in the upper abdomen. Materials and Methods. A digital camera was reengineered to remove its magnetic parts and was further equipped with a 7 m long USB cable. The system was electromagnetically shielded and operated inside the bore of a closed 3T clinical scanner. Suitable triggers were generated based on real-time motion analysis of the images produced by the camera (resolution 640×480 pixels, 30 fps. Respiratory-gated MR-ARFI prepared MRgHIFU ablation was performed in the kidney and liver of two sheep in vivo, under general anaesthesia and ventilator-driven forced breathing. Results. The optical device demonstrated very good MR compatibility. The current setup permitted the acquisition of motion artefact-free and high resolution MR 2D ARFI and multiplanar interleaved PRFS thermometry (average SNR 30 in liver and 56 in kidney. Microscopic histology indicated precise focal lesions with sharply delineated margins following the respiratory-gated HIFU sonications. Conclusion. The proof-of-concept for respiratory motion management in MRgHIFU using an in-bore digital camera has been validated in vivo.

A Shear-Wave Seismic System to Look Ahead of a Tunnel Boring Machine

NARCIS (Netherlands)

Bharadwaj, Pawan; Drijkoningen, G.G.; Mulder, W.A.; Tscharner, Thomas; Jenneskens, Rob

2016-01-01

The Earth’s properties, composition and structure ahead of a tunnel boring machine (TBM) should be mapped for hazard assessment during excavation. We study the use of seismic-exploration techniques for this purpose. We focus on a seismic system for soft soils, where shear waves are better and easier

Ultra narrow bore thick film capillaries for microcolumn separations. Part 1. GC experiments

NARCIS (Netherlands)

Steenackers, D.; Sandra, P.J.F.; Sandra, P.; Devos, G.

1993-01-01

Ultra narrow bore (50 mum 1.0.) fused silica columns were statically coated with apolar stationary phases to obtain beta values ranging from 6.25 to 50 (filmthickness 2 to 0.25 mum). Performance of the 1 and 2 mum columns in Capillary Gas Chromatography (CGC) is highlighted.

Black Holes

OpenAIRE

Horowitz, Gary T.; Teukolsky, Saul A.

1998-01-01

Black holes are among the most intriguing objects in modern physics. Their influence ranges from powering quasars and other active galactic nuclei, to providing key insights into quantum gravity. We review the observational evidence for black holes, and briefly discuss some of their properties. We also describe some recent developments involving cosmic censorship and the statistical origin of black hole entropy.

An MRI-Conditional External Cardiac Defibrillator for Resuscitation Within the MRI Scanner Bore

Science.gov (United States)

Schmidt, Ehud J.; Watkins, Ronald D.; Zviman, Menekhem M.; Guttman, Michael A.; Wang, Wei; Halperin, Henry A.

2016-01-01

Background Subjects undergoing cardiac arrest within an MRI scanner are currently removed from the bore and then from the MRI suite, prior to delivery of CPR and defibrillation, potentially increasing risk of mortality. This precludes many higher-risk (acute-ischemic, acute-stroke) patients from undergoing MRI imaging and MRI-guided intervention. An MRI-conditional cardiac defibrillator should enable scanning with defibrillation pads attached and the generator ON, enabling application of defibrillation within the MRI seconds after a cardiac event. An MRI-conditional external defibrillator may improve patient acceptance for MRI procedures. Methods and Results A commercial external defibrillator was rendered 1.5 Tesla MRI-conditional by addition of novel Radio-Frequency (RF) filters between the generator and commercial disposable surface-pads. The RF filters reduced emission into the MRI scanner, and prevented cable/surface-pad heating during imaging, while preserving all the defibrillator’s monitoring and delivery functions. Human volunteers were imaged using high Specific-Absorption-Rate sequences to validate MRI image quality (IQ) and lack of heating. Swine were electrically fibrillated (N=4) and thereafter defibrillated both outside and inside the MRI bore. MRI IQ was reduced by 0.8 or 1.6 dB, with the generator in monitoring mode and operating on battery or AC power, respectively. Commercial surface-pads did not create artifacts deeper than 6mm below the skin surface. RF heating was within FDA guidelines. Defibrillation was completely successful inside and outside the MRI bore. Conclusions A prototype MRI-conditional defibrillation system successfully defibrillated in the MRI without degrading image quality, or increasing the time needed for defibrillation. It can increase patient acceptance for MRI procedures. PMID:27729363

Black hole levitron

International Nuclear Information System (INIS)

Arsiwalla, Xerxes D.; Verlinde, Erik P.

2010-01-01

We study the problem of spatially stabilizing four dimensional extremal black holes in background electric/magnetic fields. Whilst looking for stationary stable solutions describing black holes placed in external fields we find that taking a continuum limit of Denef et al.'s multicenter supersymmetric black hole solutions provides a supergravity description of such backgrounds within which a black hole can be trapped within a confined volume. This construction is realized by solving for a levitating black hole over a magnetic dipole base. We comment on how such a construction is akin to a mechanical levitron.

Noncommutative black holes

Energy Technology Data Exchange (ETDEWEB)

Lopez-DomInguez, J C [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); Obregon, O [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); RamIrez, C [Facultad de Ciencias FIsico Matematicas, Universidad Autonoma de Puebla, PO Box 1364, 72000 Puebla (Mexico); Sabido, M [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico)

2007-11-15

We study noncommutative black holes, by using a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate Hawking's temperature and entropy for the 'noncommutative' Schwarzschild black hole.

Black hole critical phenomena without black holes

Indian Academy of Sciences (India)

large values of Ф, black holes do form and for small values the scalar field ... on the near side of the ridge ultimately evolve to form black holes while those configu- ... The inset shows a bird's eye view looking down on the saddle point.

Search for black holes

International Nuclear Information System (INIS)

Cherepashchuk, Anatolii M

2003-01-01

Methods and results of searching for stellar mass black holes in binary systems and for supermassive black holes in galactic nuclei of different types are described. As of now (June 2002), a total of 100 black hole candidates are known. All the necessary conditions Einstein's General Relativity imposes on the observational properties of black holes are satisfied for candidate objects available, thus further assuring the existence of black holes in the Universe. Prospects for obtaining sufficient criteria for reliably distinguishing candidate black holes from real black holes are discussed. (reviews of topical problems)

Interpretation of Geological Correlation Borings 1, 2, 3 in the A/M Area of the Savannah River Site, South Carolina

International Nuclear Information System (INIS)

Wyatt, D.E.; Cumbest, R.J.; Aadland, R.K.; Syms, F.H.; Stephenson, D.E.; Sherrill, J.C.

1997-06-01

The Geophysical Correlation Boring (GCB) Program was organized to provide a comprehensive correlation capability between geological core and advanced borehole geophysical data, surface high resolution reflection seismic information and, when available, borehole geochemical and cone penetrometer data. This report provides results and initial geological interpretations of borings one, two, and three (GCB-1, GCB-2, GCB-3) located within the Upper Three Runs Watershed (A/M Area) of the Savannah River Site

An Intense Traveling Airglow Front in the Upper Mesosphere-Lower Thermosphere with Characteristic of a Turbulent Bore Observed over Alice Springs, Australia

Science.gov (United States)

Walterscheid, R. L.; Hecht, J. H.; Hickey, M. P.; Gelinas, L. J.; Vincent, R. A.; Reid, I. M.; Woithe, J.

2010-12-01

The Aerospace Corporation’s Nightglow Imager observed a large step-function change in airglow in the form of a traveling front in the OH and O2 airglow emissions over Alice Springs Australia on February 2, 2003. The front exhibited a stepwise increase of nearly a factor two in the OH brightness and a stepwise decrease in the O2 brightness. The change in brightness in each layer was associated with a strong leading disturbance followed by a train of weak barely visible waves. The OH airglow brightness behind the front was the brightness night for 02 at Alice Springs that we have measured in seven years of observations. The OH brightness was among the five brightest. The event was associated with a strong phase-locked two-day wave (TDW).We have analyzed the stability conditions for the upper mesosphere and lower thermosphere and found that the airglow layers were found in a region of strong ducting. The thermal structure was obtained from combining data from the SABER instrument on the TIMED satellite and the NRLMSISE-00 model. The wind profile was obtained by combining the HWM07 model and MF radar winds from Buckland Park Australia. We found that the TDW-disturbed profile was significantly more effective in supporting a high degree of ducting than a profile based only on HWM07 winds. Dramatic wall events have been interpreted as manifestations of undular bores (e.g., Smith et al. [2003]). Undular bores are nonlinear high Froude number events that must generate an ever increasing train of waves to carry the excess energy away from the bore front. Only a very weak wave train behind the initial disturbance was seen for the Alice Springs event. The form of the amplitude ordering was not typical of a nonlinear wave train. Therefore a bore interpretation requires another means of energy dissipation, namely turbulent dissipation. We suggest that a reasonable interpretation of the observed event is a turbulent bore. We are unaware of any previous event having

Bored tunnel storage of nuclear waste

International Nuclear Information System (INIS)

Penberthy, L.

1983-01-01

Contrary to the current emphasis on deep geologic disposal of high-level nuclear waste, simple bored tunnels offer many advantages. Much lower cost is important in this period of severe budget crisis. Recoverability is feasible from a tunnel in a mountain, but dubious from a flooded mine 3000 ft deep. It is quite possible that the world will need the breeder energy cycle urgently 200 years from now. In the writer's opinion, it would be a sin for our generation to make so much fertile and fissile uranium fuel unavailable for future generations. Storage conditions in a near-surface repository are much better than deep because the temperature can be kept down, pressure will be atmospheric instead of potentially 1200 psi, and flooding will not occur. The so-called ''hydrothermal'' conditions are thus completely avoided. Accordingly, endless studies of hydrogeology, water pathway times, waste-host rock interactions and the like are unnecessary, and the time for action is much shorter

A research for Class II defect Bored Pile’s Accept Criteria: A case of Penang Second Marine bridge

Science.gov (United States)

Huang, Kang

2018-03-01

The aim of this preliminary research is to study the accept criteria of class II bored pile with subtle defect. According to a detailed comparison of the existed different standards, Chinese ones are more applicable especially for the large diameter bored piles. Through the concrete coring at pile No P25-03 of this case and the comparison to the actual calculation, the Class II pile’s defects were very minor. Comparison was also made for the effects on pile structural capacities before and after repair of the defects. the feasible repair proposal may bring forward to more defects to the piles. The Class II piles don’t need any further repairation when piles have typical of similar character and sonic logging test result with P25-03‘s one. For other Class II piles with some differences in characters, verification is needed through further concrete coring on the pile. The recommendation of this research could be adopted for the similar huge marine structures which installed large diameter bored piles.

An Account on marine wood-boring organisms of offshore waters of Bombay High, India

Digital Repository Service at National Institute of Oceanography (India)

Wagh, A.B.; Raveendran, T.V.

An incidence of wood-boring organisms in a water column of 75 meters depth, 160 km off the Bombay coast is reported. The destruction of untreated panels of mango wood exposed for periods varying from 1-12 months was caused by eight species...

Grouting guidelines for Hanford Tanks Initiative cone penetrometer borings

International Nuclear Information System (INIS)

Iwatate, D.F.

1998-01-01

Grouting of an open cone penetrometer (CP) borehole is done to construct a barrier that prevents the vertical migration of fluids and contaminants between geologic units and aquifers intersected by the boring. Whether to grout, the types of grout, and the method of deployment are functions of the site-specific conditions. This report recommends the strategy that should be followed both before and during HTI [Hanford Tanks Initiative] CP deployment to decide specific borehole grouting needs at Hanford SST farms. Topics discussed in this report that bear on this strategy include: Regulatory guidance, hydrogeologic conditions, operational factors, specific CP grouting deployment recommendations

Analysis of in-situ renewal technology for the backhoe bucket bores

Energy Technology Data Exchange (ETDEWEB)

Torims, Toms; Ratkus, Andris; Vilcans, Janis; Zarins, Marcis; Rusa, Aldis [Department of Material Processing Technology Faculty of Transport and Mechanical Engineering Riga Technical University, Riga (Latvia)

2011-07-01

The overall aim of this article is to outline the progress of the research on how to develop an economically and scientifically justified backhoe buckets boreholes renewal technology by using mobile on-site technological equipment. Today the new mobile (in-situ) repair technologies are extensively used for the specialized equipment and machinery repairs. This repair technology is deployed directly on the damaged product: repair equipment is installed by using specialized centering devices. The bucket bores central axes are used as a reference base and damaged layer of material is removed mechanically applying turning operation. Subsequently the renewable surface is covered by new material layer by means of regular MIG/MAG welding. The last technological operation is final turning to the nominal diameter. Outlined renewal technology should meet high expectations – this necessitates in-depth and systematic study of pins and bores which are the most repaired objects of shovel bucket excavators. Therefore, research on established accuracy and technical requirements, both for the repaired unit and technological equipment in line with in-situ repair technology specifics, has been done. It was supported by impact analysis of the technological regimes to surface integrity with ambition to provide practical recommendations for the optimal choice of the technological regimes. Key words: in-situ repair technology, surface integrity, technological parameters.

Stakeout electronic total station construction layout boring of the experience and precision

International Nuclear Information System (INIS)

Xu Zhiqiang

2012-01-01

Electronic total station can simultaneously measure angle and distance, together with the appropriate calculation methods and operating skills, able to efficiently complete the survey work, this paper based on practical experience, theoretical analysis, based on total station introduced in setting out a few boring in the skills and the measurement of total station in the construction layout for accuracy. (authors)

A Dancing Black Hole

Science.gov (United States)

Shoemaker, Deirdre; Smith, Kenneth; Schnetter, Erik; Fiske, David; Laguna, Pablo; Pullin, Jorge

2002-04-01

Recently, stationary black holes have been successfully simulated for up to times of approximately 600-1000M, where M is the mass of the black hole. Considering that the expected burst of gravitational radiation from a binary black hole merger would last approximately 200-500M, black hole codes are approaching the point where simulations of mergers may be feasible. We will present two types of simulations of single black holes obtained with a code based on the Baumgarte-Shapiro-Shibata-Nakamura formulation of the Einstein evolution equations. One type of simulations addresses the stability properties of stationary black hole evolutions. The second type of simulations demonstrates the ability of our code to move a black hole through the computational domain. This is accomplished by shifting the stationary black hole solution to a coordinate system in which the location of the black hole is time dependent.

Estimation of Tsunami Bore Forces on a Coastal Bridge Using an Extreme Learning Machine

Directory of Open Access Journals (Sweden)

Iman Mazinani

2016-04-01

Full Text Available This paper proposes a procedure to estimate tsunami wave forces on coastal bridges through a novel method based on Extreme Learning Machine (ELM and laboratory experiments. This research included three water depths, ten wave heights, and four bridge models with a variety of girders providing a total of 120 cases. The research was designed and adapted to estimate tsunami bore forces including horizontal force, vertical uplift and overturning moment on a coastal bridge. The experiments were carried out on 1:40 scaled concrete bridge models in a wave flume with dimensions of 24 m × 1.5 m × 2 m. Two six-axis load cells and four pressure sensors were installed to the base plate to measure forces. In the numerical procedure, estimation and prediction results of the ELM model were compared with Genetic Programming (GP and Artificial Neural Networks (ANNs models. The experimental results showed an improvement in predictive accuracy, and capability of generalization could be achieved by the ELM approach in comparison with GP and ANN. Moreover, results indicated that the ELM models developed could be used with confidence for further work on formulating novel model predictive strategy for tsunami bore forces on a coastal bridge. The experimental results indicated that the new algorithm could produce good generalization performance in most cases and could learn thousands of times faster than conventional popular learning algorithms. Therefore, it can be conclusively obtained that utilization of ELM is certainly developing as an alternative approach to estimate the tsunami bore forces on a coastal bridge.

Keeping Research Data from the Continental Deep Drilling Programme (KTB) Accessible and Taking First Steps Towards Digital Preservation

Science.gov (United States)

Klump, J. F.; Ulbricht, D.; Conze, R.

2014-12-01

The Continental Deep Drilling Programme (KTB) was a scientific drilling project from 1987 to 1995 near Windischeschenbach, Bavaria. The main super-deep borehole reached a depth of 9,101 meters into the Earth's continental crust. The project used the most current equipment for data capture and processing. After the end of the project key data were disseminated through the web portal of the International Continental Scientific Drilling Program (ICDP). The scientific reports were published as printed volumes. As similar projects have also experienced, it becomes increasingly difficult to maintain a data portal over a long time. Changes in software and underlying hardware make a migration of the entire system inevitable. Around 2009 the data presented on the ICDP web portal were migrated to the Scientific Drilling Database (SDDB) and published through DataCite using Digital Object Identifiers (DOI) as persistent identifiers. The SDDB portal used a relational database with a complex data model to store data and metadata. A PHP-based Content Management System with custom modifications made it possible to navigate and browse datasets using the metadata and then download datasets. The data repository software eSciDoc allows storing self-contained packages consistent with the OAIS reference model. Each package consists of binary data files and XML-metadata. Using a REST-API the packages can be stored in the eSciDoc repository and can be searched using the XML-metadata. During the last maintenance cycle of the SDDB the data and metadata were migrated into the eSciDoc repository. Discovery metadata was generated following the GCMD-DIF, ISO19115 and DataCite schemas. The eSciDoc repository allows to store an arbitrary number of XML-metadata records with each data object. In addition to descriptive metadata each data object may contain pointers to related materials, such as IGSN-metadata to link datasets to physical specimens, or identifiers of literature interpreting the data

XFEM Modelling of Multi-holes Plate with Single-row and Staggered Holes Configurations

Directory of Open Access Journals (Sweden)

Supar Khairi

2017-01-01

Full Text Available Joint efficiency is the key to composite structures assembly design, good structures response is dependent upon multi-holes behavior as subjected to remote loading. Current benchmarking work were following experimental testing series taken from literature on multi-holes problem. Eleven multi-hole configurations were investigated with various pitch and gage distance of staggered holes and non-staggered holes (single-row holes. Various failure modes were exhibited, most staggered holes demonstrates staggered crack path but non-staggered holes series displayed crack path along net-section plane. Stress distribution were carried out and good agreement were exhibited in experimental observation as reported in the respective literature. Consequently, strength prediction work were carried out under quasi-static loading, most showed discrepancy between 8% -31%, better prediction were exhibited in thicker and non-staggered holes plate combinations.

Catastrophic failure of a raise boring machine during underground reaming operations

CSIR Research Space (South Africa)

James, A

1997-03-01

Full Text Available rights reserved. 1. INTRODUCTION The process of raise boring (or back reaming) has been in use for over 30 years, and has proved to be a very successful technique in underground mining operations. Its primary use... the overhaul, the equipment was moved from its underground location to the surface. All the drive head bolts were replaced. A cutaway diagram of the drive head installation, showing the relative positions of the cover, drive...

Local regularity analysis of strata heterogeneities from sonic logs

Directory of Open Access Journals (Sweden)

S. Gaci

2010-09-01

Full Text Available Borehole logs provide geological information about the rocks crossed by the wells. Several properties of rocks can be interpreted in terms of lithology, type and quantity of the fluid filling the pores and fractures.

Here, the logs are assumed to be nonhomogeneous Brownian motions (nhBms which are generalized fractional Brownian motions (fBms indexed by depth-dependent Hurst parameters H(z. Three techniques, the local wavelet approach (LWA, the average-local wavelet approach (ALWA, and Peltier Algorithm (PA, are suggested to estimate the Hurst functions (or the regularity profiles from the logs.

First, two synthetic sonic logs with different parameters, shaped by the successive random additions (SRA algorithm, are used to demonstrate the potential of the proposed methods. The obtained Hurst functions are close to the theoretical Hurst functions. Besides, the transitions between the modeled layers are marked by Hurst values discontinuities. It is also shown that PA leads to the best Hurst value estimations.

Second, we investigate the multifractional property of sonic logs data recorded at two scientific deep boreholes: the pilot hole VB and the ultra deep main hole HB, drilled for the German Continental Deep Drilling Program (KTB. All the regularity profiles independently obtained for the logs provide a clear correlation with lithology, and from each regularity profile, we derive a similar segmentation in terms of lithological units. The lithological discontinuities (strata' bounds and faults contacts are located at the local extrema of the Hurst functions. Moreover, the regularity profiles are compared with the KTB estimated porosity logs, showing a significant relation between the local extrema of the Hurst functions and the fluid-filled fractures. The Hurst function may then constitute a tool to characterize underground heterogeneities.

Black holes will break up solitons and white holes may destroy them

International Nuclear Information System (INIS)

Akbar, Fiki T.; Gunara, Bobby E.; Susanto, Hadi

2017-01-01

Highlights: • What happens if a soliton collides with a black or white hole? • Solitons can pass through black hole horizons, but they will break up into several solitons after the collision. • In the interaction with a white hole horizon, solitons either pass through the horizon or will be destroyed by it. - Abstract: We consider a quantum analogue of black holes and white holes using Bose–Einstein condensates. The model is described by the nonlinear Schrödinger equation with a ‘stream flow’ potential, that induces a spatial translation to standing waves. We then mainly consider the dynamics of dark solitons in a black hole or white hole flow analogue and their interactions with the event horizon. A reduced equation describing the position of the dark solitons was obtained using variational method. Through numerical computations and comparisons with the analytical approximation we show that solitons can pass through black hole horizons even though they will break up into several solitons after the collision. In the interaction with a white hole horizon, we show that solitons either pass through the horizon or will be destroyed by it.

Black holes will break up solitons and white holes may destroy them

Energy Technology Data Exchange (ETDEWEB)

Akbar, Fiki T., E-mail: ftakbar@fi.itb.ac.id [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10, Bandung, 40132 (Indonesia); Gunara, Bobby E., E-mail: bobby@fi.itb.ac.id [Theoretical Physics Laboratory, Theoretical High Energy Physics and Instrumentation Research Group, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha no. 10, Bandung, 40132 (Indonesia); Susanto, Hadi, E-mail: hsusanto@essex.ac.uk [Department of Mathematical Sciences, University of Essex, Colchester, CO4 3SQ (United Kingdom)

2017-06-15

Highlights: • What happens if a soliton collides with a black or white hole? • Solitons can pass through black hole horizons, but they will break up into several solitons after the collision. • In the interaction with a white hole horizon, solitons either pass through the horizon or will be destroyed by it. - Abstract: We consider a quantum analogue of black holes and white holes using Bose–Einstein condensates. The model is described by the nonlinear Schrödinger equation with a ‘stream flow’ potential, that induces a spatial translation to standing waves. We then mainly consider the dynamics of dark solitons in a black hole or white hole flow analogue and their interactions with the event horizon. A reduced equation describing the position of the dark solitons was obtained using variational method. Through numerical computations and comparisons with the analytical approximation we show that solitons can pass through black hole horizons even though they will break up into several solitons after the collision. In the interaction with a white hole horizon, we show that solitons either pass through the horizon or will be destroyed by it.

Caged black holes: Black holes in compactified spacetimes. I. Theory

International Nuclear Information System (INIS)

Kol, Barak; Sorkin, Evgeny; Piran, Tsvi

2004-01-01

In backgrounds with compact dimensions there may exist several phases of black objects including a black hole and a black string. The phase transition between them raises questions and touches on fundamental issues such as topology change, uniqueness, and cosmic censorship. No analytic solution is known for the black hole, and moreover one can expect approximate solutions only for very small black holes, while phase transition physics happens when the black hole is large. Hence we turn to numerical solutions. Here some theoretical background to the numerical analysis is given, while the results will appear in a subsequent paper. The goals for a numerical analysis are set. The scalar charge and tension along the compact dimension are defined and used as improved order parameters which put both the black hole and the black string at finite values on the phase diagram. The predictions for small black holes are presented. The differential and the integrated forms of the first law are derived, and the latter (Smarr's formula) can be used to estimate the 'overall numerical error'. Field asymptotics and expressions for physical quantities in terms of the numerical values are supplied. The techniques include the 'method of equivalent charges', free energy, dimensional reduction, and analytic perturbation for small black holes

Alternate Explosions: Collapse and Accretion Events with Red Holes instead of Black Holes

OpenAIRE

Graber, James S.

1999-01-01

A red hole is "just like a black hole" except it lacks an event horizon and a singularity. As a result, a red hole emits much more energy than a black hole during a collapse or accretion event. We consider how a red hole solution can solve the "energy crisis" and power extremely energetic gamma ray bursts and hypernovae.

Flexible add-on solution for MR image-guided interventions in a closed-bore scanner environment.

Science.gov (United States)

Busse, Harald; Garnov, Nikita; Thörmer, Gregor; Zajonz, Dirk; Gründer, Wilfried; Kahn, Thomas; Moche, Michael

2010-09-01

MRI is of great clinical utility for the guidance of various diagnostic and therapeutic procedures. In a standard closed-bore scanner, the simplest approach is to manipulate the instrument outside the bore and move the patient into the bore for reference and control imaging only. Without navigational assistance, however, such an approach can be difficult, inaccurate, and time consuming. Therefore, an add-on navigation solution is described that addresses these limitations. Patient registration is established by an automatic, robust, and fast (<30 sec) localization of table-mounted MR reference markers and the instrument is tracked optically. Good hand-eye coordination is provided by following the virtual instrument on MR images that are reconstructed in real time from the reference data. Needle displacements of 2.2 +/- 0.6 mm and 3.9 +/- 2.4 mm were determined in a phantom (P < 0.05), depending on whether the reference markers were placed at smaller (98-139 mm) or larger (147-188 mm) distances from the isocenter. Clinical functionality of the navigation concept is demonstrated by a double oblique, subscapular hook-wire insertion in a patient with a body mass index of 30.1 kg/m(2). Ease of use, compactness, and flexibility of this technique suggest that it can be used for many other procedures in different body regions. More patient cases are needed to evaluate clinical performance and workflow. 2010 Wiley-Liss, Inc.

Black and white holes

International Nuclear Information System (INIS)

Zeldovich, Ya.; Novikov, I.; Starobinskij, A.

1978-01-01

The theory is explained of the origination of white holes as a dual phenomenon with regard to the formation of black holes. Theoretically it is possible to derive the white hole by changing the sign of time in solving the general theory of relativity equation implying the black hole. The white hole represents the amount of particles formed in the vicinity of a singularity. For a distant observer, matter composed of these particles expands and the outer boundaries of this matter approach from the inside the gravitational radius Rsub(r). At t>>Rsub(r)/c all radiation or expulsion of matter terminates. For the outside observer the white hole exists for an unlimited length of time. In fact, however, it acquires the properties of a black hole and all processes in it cease. The qualitative difference between a white hole and a black hole is in that a white hole is formed as the result of an inner quantum explosion from the singularity to the gravitational radius and not as the result of a gravitational collapse, i.e., the shrinkage of diluted matter towards the gravitational radius. (J.B.)

Black and white holes

Energy Technology Data Exchange (ETDEWEB)

Zeldovich, Ya; Novikov, I; Starobinskii, A

1978-07-01

The theory is explained of the origination of white holes as a dual phenomenon with regard to the formation of black holes. Theoretically it is possible to derive the white hole by changing the sign of time in solving the general theory of relativity equation implying the black hole. The white hole represents the amount of particles formed in the vicinity of a singularity. For a distant observer, matter composed of these particles expands and the outer boundaries of this matter approach from the inside the gravitational radius R/sub r/. At t>>R/sub r//c all radiation or expulsion of matter terminates. For the outside observer the white hole exists for an unlimited length of time. In fact, however, it acquires the properties of a black hole and all processes in it cease. The qualitative difference between a white hole and a black hole is in that a white hole is formed as the result of an inner quantum explosion from the singularity to the gravitational radius and not as the result of a gravitational collapse, i.e., the shrinkage of diluted matter towards the gravitational radius.

Astrophysical black holes

CERN Document Server

Gorini, Vittorio; Moschella, Ugo; Treves, Aldo; Colpi, Monica

2016-01-01

Based on graduate school lectures in contemporary relativity and gravitational physics, this book gives a complete and unified picture of the present status of theoretical and observational properties of astrophysical black holes. The chapters are written by internationally recognized specialists. They cover general theoretical aspects of black hole astrophysics, the theory of accretion and ejection of gas and jets, stellar-sized black holes observed in the Milky Way, the formation and evolution of supermassive black holes in galactic centers and quasars as well as their influence on the dynamics in galactic nuclei. The final chapter addresses analytical relativity of black holes supporting theoretical understanding of the coalescence of black holes as well as being of great relevance in identifying gravitational wave signals. With its introductory chapters the book is aimed at advanced graduate and post-graduate students, but it will also be useful for specialists.

Geotechnical maps for recommendation on bored pile capacity in Nakhon Ratchasima municipality, Thailand

Directory of Open Access Journals (Sweden)

Suksun Horpibulsuk

2013-08-01

Full Text Available This paper presents the development of geotechnical maps in Nakhon Ratchasima municipality, Nakhon Ratchasima province, Thailand based on the boring logs and in situ test results collected from public and private sector sources. The standard penetration number, N was used to identify the soil type. The soil deposits in Nakhon Ratchasima municipality are divided into three layers: medium-to-stiff silty clay with N 50. The medium-to-stiff silty clay layer has a thickness varying from 1.8 to 7.5 metres and an average N value of 14 with a relatively low standard deviation of 1.08. The first hard silty clay layer has a thickness varying from 1.2 to 3.0 metres and an average N value of 42 with a standard deviation of 1.37. For a practical application in foundation engineering in which the pile tips of the bored piles are located in the second hard stratum with N > 50, eight pile tip zones with approximated load capacity are recommended for pile lengths of 3-10 metres.

Fragmentation Energy-Saving Theory of Full Face Rock Tunnel Boring Machine Disc Cutters

Science.gov (United States)

Zhang, Zhao-Huang; Gong, Guo-Fang; Gao, Qing-Feng; Sun, Fei

2017-07-01

Attempts to minimize energy consumption of a tunnel boring machine disc cutter during the process of fragmentation have largely focused on optimizing disc-cutter spacing, as determined by the minimum specific energy required for fragmentation; however, indentation tests showed that rock deforms plastically beneath the cutters. Equations for thrust were developed for both the traditional, popularly employed disc cutter and anew design based on three-dimensional theory. The respective energy consumption for penetration, rolling, and side-slip fragmentations were obtained. A change in disc-cutter fragmentation angles resulted in a change in the nature of the interaction between the cutter and rock, which lowered the specific energy of fragmentation. During actual field excavations to the same penetration length, the combined energy consumption for fragmentation using the newly designed cutters was 15% lower than that when using the traditional design. This paper presents a theory for energy saving in tunnel boring machines. Investigation results showed that the disc cutters designed using this theory were more durable than traditional designs, and effectively lowered the energy consumption.

Plastohydrodynamic drawing and coating of stainless steel wire using a tapered bore die of no metal to metal contact

Science.gov (United States)

Hasan, S.; Basmage, O.; Stokes, J. T.; Hashmi, M. S. J.

2018-05-01

A review of wire coating studies using plasto-hydrodynamic pressure shows that most of the works were carried out by conducting experiments simultaneously with simulation analysis based upon Bernoulli's principle and Euler and Navier-Stokes (N-S) equations. These characteristics relate to the domain of Computational Fluid Dynamics (CFD) which is an interdisciplinary topic (Fluid Mechanics, Numerical Analysis of Fluid flow and Computer Science). This research investigates two aspects: (i) simulation work and (ii) experimentation. A mathematical model was developed to investigate the flow pattern of the molten polymer and pressure distribution within the wire-drawing dies, assessment of polymer coating thickness on the coated wires and speed of coating on the wires at the outlet of the drawing dies, without deploying any pressurizing pump. In addition to a physical model which was developed within ANSYS™ environment through the simulation design of ANSYS™ Workbench. The design was customized to simulate the process of wire-coating on the fine stainless-steel wires using drawing dies having different bore geometries such as: stepped parallel bore, tapered bore and combined parallel and tapered bore. The convergence of the designed CFD model and numerical and physical solution parameters for simulation were dynamically monitored for the viscous flow of the polypropylene (PP) polymer. Simulation results were validated against experimental results and used to predict the ideal bore shape to produce a thin coating on stainless wires with different diameter. Simulation studies confirmed that a specific speed should be attained by the stainless-steel wires while passing through the drawing dies. It has been observed that all the speed values within specific speed range did not produce a coating thickness having the desired coating characteristic features. Therefore, some optimization of the experimental set up through design of experiments (Stat-Ease) was applied to

System safety analysis of the Yucca Mountain tunnel boring machine

International Nuclear Information System (INIS)

Smith, M.G.; Booth, L.; Eisler, L.

1995-01-01

The purpose of this analysis was to systematically identify and evaluate hazards related to the tunnel boring machine to be used at Yucca Mountain. This analysis required three steps to complete the risk evaluation: hazard/scenario identification, consequence assessment, and frequency assessment. The result was a 'risk evaluation' of the scenarios identified in this analysis in accordance with MIL-STD-882C. The risk assessment in this analysis characterized the accident scenarios associated with the TBM in terms of relative risk and included recommendations for mitigating all identified risks

Cold water injection nozzles

International Nuclear Information System (INIS)

Kura, Masaaki; Maeda, Masamitsu; Endo, Takio.

1979-01-01

Purpose: To inject cold water in a reactor without applying heat cycles to a reactor container and to the inner wall of a feedwater nozzle by securing a perforated plate at the outlet of the cold water injection nozzle. Constitution: A disc-like cap is secured to the final end of a return nozzle of a control rod drive. The cap prevents the flow of a high temperature water flowing downward in the reactor from entering into the nozzle. The cap is perforated with a plurality of bore holes for injecting cold water into the reactor. The cap is made to about 100 mm in thickness so that the cold water passing through the bore holes is heated by the heat conduction in the cap. Accordingly, the flow of high temperature water flowing downwardly in the reactor is inhibited by the cap from backward flowing into the nozzle. Moreover, the flow of the cold water in the nozzle is controlled and rectified when passed through the bore holes in the cap and then injected into the reactor. (Yoshino, Y.)

Black holes in binary stars

NARCIS (Netherlands)

Wijers, R.A.M.J.

1996-01-01

Introduction Distinguishing neutron stars and black holes Optical companions and dynamical masses X-ray signatures of the nature of a compact object Structure and evolution of black-hole binaries High-mass black-hole binaries Low-mass black-hole binaries Low-mass black holes Formation of black holes

The stable problem of the black-hole connected region in the Schwarzschild black hole

OpenAIRE

Tian, Guihua

2005-01-01

The stability of the Schwarzschild black hole is studied. Using the Painlev\\'{e} coordinate, our region can be defined as the black-hole-connected region(r>2m, see text) of the Schwarzschild black hole or the white-hole-connected region(r>2m, see text) of the Schwarzschild black hole. We study the stable problems of the black-hole-connected region. The conclusions are: (1) in the black-hole-connected region, the initially regular perturbation fields must have real frequency or complex frequen...

A study on optimal scan conditions of big bore multi-slice computed tomography based on radiation dose and image noise

International Nuclear Information System (INIS)

Lee, J. S.; Ye, S. J.; Kim, E. H.

2011-01-01

The newly introduced Big Bore computed tomography (CT) has a possibility to increase the tube current product scan time (mA s) for compensation of image degradation due to larger gentry opening without sound guideline. The objective of this paper is to derive optimal scan conditions for Big Bore CT scanner, mainly relating to the dose of diagnostic CT. The weighted CT dose index (CTDI w ) was estimated at five typical protocols, such as head and neck, brain, paediatric, chest and abdomen. Noises were analysed in a circle of 1 or 2 cm of diameter in CT image slice. The results showed that measured CTDI w values generally follow the theoretical rule at all scanning conditions of every protocol. Although image noises decrease with increment of mA s, analysed image noises do follow the theoretical rule, but only in specific protocols. This phenomenon is presumed to result from the photon energy spectra arriving at the detection system of the Big Bore scanner. (authors)

Rotating black holes at future colliders. III. Determination of black hole evolution

International Nuclear Information System (INIS)

Ida, Daisuke; Oda, Kin-ya; Park, Seong Chan

2006-01-01

TeV scale gravity scenario predicts that the black hole production dominates over all other interactions above the scale and that the Large Hadron Collider will be a black hole factory. Such higher-dimensional black holes mainly decay into the standard model fields via the Hawking radiation whose spectrum can be computed from the greybody factor. Here we complete the series of our work by showing the greybody factors and the resultant spectra for the brane-localized spinor and vector field emissions for arbitrary frequencies. Combining these results with the previous works, we determine the complete radiation spectra and the subsequent time evolution of the black hole. We find that, for a typical event, well more than half a black hole mass is emitted when the hole is still highly rotating, confirming our previous claim that it is important to take into account the angular momentum of black holes

Black holes. Chapter 6

International Nuclear Information System (INIS)

Penrose, R.

1980-01-01

Conditions for the formation of a black hole are considered, and the properties of black holes. The possibility of Cygnus X-1 as a black hole is discussed. Einstein's theory of general relativity in relation to the formation of black holes is discussed. (U.K.)

Distribution and biomass estimation of shell-boring algae in the intertidal area at Goa India

Digital Repository Service at National Institute of Oceanography (India)

Raghukumar, C.; Sharma, S.; Lande, V.

The distribution and frequency of shell-boring green and blue-green algae in the intertidal at Goa, India were studied. The green alga Gomontia sp. and the blue green algae Hyella caespitosa Bornet et Flahault, H. gigas Lucas et Golubic...

Statistical black-hole thermodynamics

International Nuclear Information System (INIS)

Bekenstein, J.D.

1975-01-01

Traditional methods from statistical thermodynamics, with appropriate modifications, are used to study several problems in black-hole thermodynamics. Jaynes's maximum-uncertainty method for computing probabilities is used to show that the earlier-formulated generalized second law is respected in statistically averaged form in the process of spontaneous radiation by a Kerr black hole discovered by Hawking, and also in the case of a Schwarzschild hole immersed in a bath of black-body radiation, however cold. The generalized second law is used to motivate a maximum-entropy principle for determining the equilibrium probability distribution for a system containing a black hole. As an application we derive the distribution for the radiation in equilibrium with a Kerr hole (it is found to agree with what would be expected from Hawking's results) and the form of the associated distribution among Kerr black-hole solution states of definite mass. The same results are shown to follow from a statistical interpretation of the concept of black-hole entropy as the natural logarithm of the number of possible interior configurations that are compatible with the given exterior black-hole state. We also formulate a Jaynes-type maximum-uncertainty principle for black holes, and apply it to obtain the probability distribution among Kerr solution states for an isolated radiating Kerr hole

Black hole hair removal

International Nuclear Information System (INIS)

Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke

2009-01-01

Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair - degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

Aspiration of breast abscess through wide bore 14-gauge intravenous cannula.

Science.gov (United States)

Afridi, Shahida Parveen; Alam, Shams Nadeem; Ainuddin, Saman

2014-10-01

To aspirate breast abscess through a wide bore (14-gauge) intravenous (I/V) cannula and determine its efficacy in terms of the number of recurrences and number of aspirations. Case series. Dow University of Health Sciences and Civil Hospital and Bantva Hospital, Karachi, Pakistan, from January 2009 to December 2011. Patients with breast abscesses confirmed on ultrasound without skin ulceration were selected. The soft area of breast abscess with positive fluctuation was marked and fixed with index finger and thumb. A 14-gauge cannula was inserted. Pus was aspirated through a 50 cc syringe, repeated till no aspirate could be obtained. All patients were followed weekly for 4 weeks, clinically for size of lump, local tenderness and temperature, while complete resolution was confirmed on ultrasound, as resolution of the lesion. A total of 55 patients were included in this study. Mean age was 29 ± 5.58 years while ranging from 20 - 40 years. Complete resolution of abscess was seen in 31 (56.4%) cases by single aspiration. Second aspiration was required in 24 (43.6%) patients and third aspiration in single setting was required in one case only. Recurrence after the second aspiration occurred in 08 (14.5%). Incision drainage was required in 7 (12.7%) patients. Percutaneous aspiration of breast abscess through a wide bore (14-gauge) I/V cannula is a simple alternative to incision and drainage.

Temperature calculations on different configurations for disposal of high-level reprocessing waste in a salt dome model

International Nuclear Information System (INIS)

Hamstra, J.; Kevenaar, J.W.A.M.

1978-06-01

A medium size salt dome is considered as a structure in which a repository can be located for all radioactive wastes to be produced within the scope of a postulated nuclear power program. A dominating design factor for the lay-out of such a waste repository is the temperature distribution in the salt dome resulting from decay heat released from the buried solidified high-level reprocessing waste. Two numerical models are presented for the calculation of both global and local rock salt temperatures. The results of calculations performed with these models are demonstrated to be compatible. Rock salt temperatures related to several types of burial configurations, ranging from two layer configurations with various vertical distances between the layers via a three and a four layer repository to deep bore hole concepts varying from 100 to 600 m bore hole depth, can therefore be calculated with one rather simple unit cell model. The results of these calculations indicate that rock salt temperatures can be kept within acceptable limits to realize a repository using standard mining techniques. The temperatures at mine galery level prove to be a dominating factor in the selection of a repository configuration. More detailed calculations of these temperatures taking into account the loading sequence and the cooling capacity of the mine ventilation are recommended. Finally the apparent advantages of a deep bore hole concept emphasize the need for R and D work with respect to advanced drilling techniques in order to achieve deep dry disposal bore holes that can be realized from a burial mine in the salt dome. (Auth.)

Magnetic susceptibility measurements of boring cores obtained from regional hydrological study project

International Nuclear Information System (INIS)

Hasegawa, Ken

2010-02-01

We measured the magnetic susceptibility of boring cores obtained from the Regional Hydrological Study Project to interpret the aeromagnetic survey data which was carried out in Tono area with about 40km square surrounding Tono Geoscience Center. The result of measurements indicates that the magnetic susceptibility of the Toki Granite is not distributed uniformly and the maximum value becomes two orders in magnitude larger than its minimum value. (author)

Brane holes

International Nuclear Information System (INIS)

Frolov, Valeri P.; Mukohyama, Shinji

2011-01-01

The aim of this paper is to demonstrate that in models with large extra dimensions under special conditions one can extract information from the interior of 4D black holes. For this purpose we study an induced geometry on a test brane in the background of a higher-dimensional static black string or a black brane. We show that, at the intersection surface of the test brane and the bulk black string or brane, the induced metric has an event horizon, so that the test brane contains a black hole. We call it a brane hole. When the test brane moves with a constant velocity V with respect to the bulk black object, it also has a brane hole, but its gravitational radius r e is greater than the size of the bulk black string or brane r 0 by the factor (1-V 2 ) -1 . We show that bulk ''photon'' emitted in the region between r 0 and r e can meet the test brane again at a point outside r e . From the point of view of observers on the test brane, the events of emission and capture of the bulk photon are connected by a spacelike curve in the induced geometry. This shows an example in which extra dimensions can be used to extract information from the interior of a lower-dimensional black object. Instead of the bulk black string or brane, one can also consider a bulk geometry without a horizon. We show that nevertheless the induced geometry on the moving test brane can include a brane hole. In such a case the extra dimensions can be used to extract information from the complete region of the brane-hole interior. We discuss thermodynamic properties of brane holes and interesting questions which arise when such an extra-dimensional channel for the information mining exists.

Controlled drilling technology for HLW management. Directional drilling and mechanics/stress measurements in the borehole

International Nuclear Information System (INIS)

Kiho, Kenzo; Shin, Koichi; Okada, Tetsuji; Obuchi, Yasuyoshi; Sunaga, Takayuki; Hase, Kazunori

2013-01-01

Since 2000, Central Research Institute of Electric Power Industry (CRIEPI) has been conducting the project on controlled drilling and the logging/measurement technologies in its boreholes. Especially borehole pressure meter and bore hole stress measurement apparatus which can apply to the controlled drilling system was developed. The bore hole was drilled to the 1000 m long in order to intersect the Omagari fault located at Horonobe town in Hokkaido and its core recovery was 99.8% as of FY. 2011. Using borehole logging/measurement/survey, the geological, hydrological, geo-mechanical, geophysical and geochemical data were collected and the Omagari fault was characterized. (author)

Black holes are warm

International Nuclear Information System (INIS)

Ravndal, F.

1978-01-01

Applying Einstein's theory of gravitation to black holes and their interactions with their surroundings leads to the conclusion that the sum of the surface areas of several black holes can never become less. This is shown to be analogous to entropy in thermodynamics, and the term entropy is also thus applied to black holes. Continuing, expressions are found for the temperature of a black hole and its luminosity. Thermal radiation is shown to lead to explosion of the black hole. Numerical examples are discussed involving the temperature, the mass, the luminosity and the lifetime of black mini-holes. It is pointed out that no explosions corresponding to the prediction have been observed. It is also shown that the principle of conservation of leptons and baryons is broken by hot black holes, but that this need not be a problem. The related concept of instantons is cited. It is thought that understanding of thermal radiation from black holes may be important for the development of a quantified gravitation theory. (JIW)

Hole history, rotary hole DC-3

International Nuclear Information System (INIS)

1977-10-01

Purpose of hole DC-3 was to drill into the Umtanum basalt flow using both conventional rotary and core drilling methods. The borehole is to be utilized for geophysical logging, future hydrological testing, and the future installation of a borehole laboratory for long-term pressure, seismic, and moisture migration or accumulation recording in the Umtanum basalt flow in support of the Basalt Waste Isolation Program. Hole DC-3 is located east of the 200 West barricaded area on the Hanford reservation

Echo-Planar Imaging for a 9.4 Tesla Vertical-Bore Superconducting Magnet Using an Unshielded Gradient Coil.

Science.gov (United States)

Kodama, Nao; Kose, Katsumi

2016-10-11

Echo-planar imaging (EPI) sequences were developed for a 9.4 Tesla vertical standard bore (~54 mm) superconducting magnet using an unshielded gradient coil optimized for live mice imaging and a data correction technique with reference scans. Because EPI requires fast switching of intense magnetic field gradients, eddy currents were induced in the surrounding metallic materials, e.g., the room temperature bore, and this produced serious artifacts on the EPI images. We solved the problem using an unshielded gradient coil set of proper size (outer diameter = 39 mm, inner diameter = 32 mm) with time control of the current rise and reference scans. The obtained EPI images of a phantom and a plant sample were almost artifact-free and demonstrated the promise of our approach.

Echo-Planar Imaging for a 9.4 Tesla Vertical-Bore Superconducting Magnet Using an Unshielded Gradient Coil

Science.gov (United States)

KODAMA, Nao; KOSE, Katsumi

2016-01-01

Echo-planar imaging (EPI) sequences were developed for a 9.4 Tesla vertical standard bore (∼54 mm) superconducting magnet using an unshielded gradient coil optimized for live mice imaging and a data correction technique with reference scans. Because EPI requires fast switching of intense magnetic field gradients, eddy currents were induced in the surrounding metallic materials, e.g., the room temperature bore, and this produced serious artifacts on the EPI images. We solved the problem using an unshielded gradient coil set of proper size (outer diameter = 39 mm, inner diameter = 32 mm) with time control of the current rise and reference scans. The obtained EPI images of a phantom and a plant sample were almost artifact-free and demonstrated the promise of our approach. PMID:27001398

Mechanics of Cutting and Boring. Part 7. Dynamics and Energetics of Axial Rotation Machines,

Science.gov (United States)

1981-12-01

systematic analytical scheme that can be used to facilitate future work on the mechanics of cutting and boring machines. In the industrial sector, rock...Proceedings. Chapter 66, p. 1149-1158. Mellor, M. and I. Hawkes (1972) How to rate a hard-rock borer. World Construction, Sept, p. 21-23. (Also in Ingenieria

Quantum aspects of black holes

CERN Document Server

2015-01-01

Beginning with an overview of the theory of black holes by the editor, this book presents a collection of ten chapters by leading physicists dealing with the variety of quantum mechanical and quantum gravitational effects pertinent to black holes. The contributions address topics such as Hawking radiation, the thermodynamics of black holes, the information paradox and firewalls, Monsters, primordial black holes, self-gravitating Bose-Einstein condensates, the formation of small black holes in high energetic collisions of particles, minimal length effects in black holes and small black holes at the Large Hadron Collider. Viewed as a whole the collection provides stimulating reading for researchers and graduate students seeking a summary of the quantum features of black holes.

Twin header bore welded steam generator for pressurized water reactors

International Nuclear Information System (INIS)

Davies, R.J.; Hirst, B.

1979-01-01

A description is given of a pressurized water reactor (PWR) steam generator concept, several examples of which have been in service for up to fourteen years. Details are given of the highly successful service record of this equipment and the features which have been incorporated to minimize corrosion and deposition pockets. The design employs a vertical U tube bundle carried off two horizontal headers to which the tubes are welded by the Foster Wheeler Power Products (FWPP) bore welding process. The factors to be considered in uprating the design to meet the current operating conditions for a 1000 MW unit are discussed. (author)

Black holes and beyond

Energy Technology Data Exchange (ETDEWEB)

NONE

2002-02-01

Belief in the existence of black holes is the ultimate act of faith for a physicist. First suggested by the English clergyman John Michell in the year 1784, the gravitational pull of a black hole is so strong that nothing - not even light - can escape. Gravity might be the weakest of the fundamental forces but black-hole physics is not for the faint-hearted. Black holes present obvious problems for would-be observers because they cannot, by definition, be seen with conventional telescopes - although before the end of the decade gravitational-wave detectors should be able to study collisions between black holes. Until then astronomers can only infer the existence of a black hole from its gravitational influence on other matter, or from the X-rays emitted by gas and dust as they are dragged into the black hole. However, once this material passes through the 'event horizon' that surrounds the black hole, we will never see it again - not even with X-ray specs. Despite these observational problems, most physicists and astronomers believe that black holes do exist. Small black holes a few kilometres across are thought to form when stars weighing more than about two solar masses collapse under the weight of their own gravity, while supermassive black holes weighing millions of solar masses appear to be present at the centre of most galaxies. Moreover, some brave physicists have proposed ways to make black holes - or at least event horizons - in the laboratory. The basic idea behind these 'artificial black holes' is not to compress a large amount of mass into a small volume, but to reduce the speed of light in a moving medium to less than the speed of the medium and so create an event horizon. The parallels with real black holes are not exact but the experiments could shed new light on a variety of phenomena. The first challenge, however, is to get money for the research. One year on from a high-profile meeting on artificial black holes in London, for

Non-contact and contact measurement system for detecting projectile position in electromagnetic launch bore

Science.gov (United States)

Xu, Weidong; Yuan, Weiqun; Xu, Rong; Zhao, Hui; Cheng, Wenping; Zhang, Dongdong; Zhao, Ying; Yan, Ping

2017-12-01

This paper introduces a new measurement system for measuring the position of a projectile within a rapid fire electromagnetic launching system. The measurement system contains both non-contact laser shading and metal fiber contact measurement devices. Two projectiles are placed in the rapid fire electromagnetic launch bore, one in the main accelerating segment and the other in the pre-loading segment. The projectile placed in the main accelerating segment should be shot first, and then the other is loaded into the main segment from the pre-loading segment. The main driving current (I-main) can only be discharged again when the second projectile has arrived at the key position (the projectile position corresponds to the discharging time) in the main accelerating segment. So, it is important to be able to detect when the second projectile arrives at the key position in the main accelerating segment. The B-dot probe is the most widely used system for detecting the position of the projectile in the electromagnetic launch bore. However, the B-dot signal is affected by the driving current amplitude and the projectile velocity. There is no current in the main accelerating segment when the second projectile moves into this segment in rapid fire mode, so the B-dot signal for detecting the key position is invalid. Due to the presence of a high-intensity magnetic field, a high current, a high-temperature aluminum attachment, smoke and strong vibrations, it is very difficult to detect the projectile position in the bore accurately. So, other measurements need to be researched and developed in order to achieve high reliability. A measurement system based on a laser (non-contact) and metal fibers (contact) has been designed, and the integrated output signal based on this detector is described in the following paper.

Monitoring pilot projects on bored tunnelling : The Second Heinenoord Tunnel and the Botlek Rail Tunnel

NARCIS (Netherlands)

Bakker, K.J.; De Boer, F.; Admiraal, J.B.M.; Van Jaarsveld, E.P.

1999-01-01

Two pilot projects for bored tunnelling in soft soil have been undertaken in the Netherlands. The monitoring was commissioned under the authority of the Centre for Underground Construction (COB). A description of the research related to the Second Heinenoord Tunnel and the Botlek Rail Tunnel will be

Investigation of Spiral and Sweeping Holes

Science.gov (United States)

Thurman, Douglas; Poinsatte, Philip; Ameri, Ali; Culley, Dennis; Raghu, Surya; Shyam, Vikram

2015-01-01

Surface infrared thermography, hotwire anemometry, and thermocouple surveys were performed on two new film cooling hole geometries: spiral/rifled holes and fluidic sweeping holes. The spiral holes attempt to induce large-scale vorticity to the film cooling jet as it exits the hole to prevent the formation of the kidney shaped vortices commonly associated with film cooling jets. The fluidic sweeping hole uses a passive in-hole geometry to induce jet sweeping at frequencies that scale with blowing ratios. The spiral hole performance is compared to that of round holes with and without compound angles. The fluidic hole is of the diffusion class of holes and is therefore compared to a 777 hole and Square holes. A patent-pending spiral hole design showed the highest potential of the non-diffusion type hole configurations. Velocity contours and flow temperature were acquired at discreet cross-sections of the downstream flow field. The passive fluidic sweeping hole shows the most uniform cooling distribution but suffers from low span-averaged effectiveness levels due to enhanced mixing. The data was taken at a Reynolds number of 11,000 based on hole diameter and freestream velocity. Infrared thermography was taken for blowing rations of 1.0, 1.5, 2.0, and 2.5 at a density ration of 1.05. The flow inside the fluidic sweeping hole was studied using 3D unsteady RANS.

Black Hole Area Quantization rule from Black Hole Mass Fluctuations

OpenAIRE

Schiffer, Marcelo

2016-01-01

We calculate the black hole mass distribution function that follows from the random emission of quanta by Hawking radiation and with this function we calculate the black hole mass fluctuation. From a complete different perspective we regard the black hole as quantum mechanical system with a quantized event horizon area and transition probabilities among the various energy levels and then calculate the mass dispersion. It turns out that there is a perfect agreement between the statistical and ...

Project JADE. Description of the MLH-method

International Nuclear Information System (INIS)

Sandstedt, H.; Munier, R.; Wichmann, C.; Isaksson, Therese

2001-08-01

This report constitutes a part of a series of reports within project JADE, comparison of deposition methods. A comparison of the deposition methods MLH (Medium Long Holes with approximately 25 copper canisters emplaced in a horizontal deposition hole about 200 metres in length bored between central and side tunnels) and KBS-3 (copper canisters are emplaced in vertical deposition holes bored in the floors of horizontal tunnels) has earlier been performed and KBS-3 was judged to be more advantageous than MLH. However, the prerequisites for the comparison have changed with time and an updated evaluation of MLH was therefore required. In this report, the current knowledge of MLH is summarized with focus on geological prerequisites, methods for boring long, horizontal deposition holes, reinforcement and sealing, deposition and cost. Comparisons with KBS-3 are performed sequentially. An MLH-repository is judged to be more sensitive to ingress of water to the deposition holes during the deposition process. This implies that a MLH repository based on today's knowledge is basically recommended for bedrock with fairly low water baring capacity. It has been demonstrated that MLH has considerable economic potential compared to KBS-3. However, the method is judged to be more technically immature than KBS-3. Particularly, methods and equipment for deposition of canisters need to be developed further. Methods and equipment for deposition can be developed, which fulfill the demands on function and safety, in the near future. MLH cannot therefore be rejected as deposition method

Dynamical 3-Space: Cosmic Filaments, Sheets and Voids

Directory of Open Access Journals (Sweden)

Cahill R. T.

2011-04-01

Full Text Available Observations of weak gravitational lensing combined with statistical tomographic techniques have revealed that galaxies have formed along filaments, essentially one- dimensional lines or strings, which form sheets and voids. These have, in the main, been interpreted as “dark matter” effects. To the contrary here we report the discovery that the dynamical 3-space theory possesses such filamentary solutions. These solutions are purely space self-interaction effects, and are attractive to matter, and as well gener- ate electromagnetic lensing. This theory of space has explained bore hole anomalies, supermassive black hole masses in spherical galaxies and globular clusters, flat rota- tion curves of spiral galaxies, and other gravitational anomalies. The theory has two constants, G and , where the bore hole experiments show that 1 = 137 is the fine structure constant.

Dynamical 3-Space: Cosmic Filaments, Sheets and Voids

Directory of Open Access Journals (Sweden)

Cahill R. T.

2011-04-01

Full Text Available Observations of weak gravitational lensing combined with statistical tomographic techniques have revealed that galaxies have formed along filaments, essentially one-dimensional lines or strings, which form sheets and voids. These have, in the main, been interpreted as "dark matter" effects. To the contrary here we report the discovery that the dynamical 3-space theory possesses such filamentary solutions. These solutions are purely space self-interaction effects, and are attractive to matter, and as well generate electromagnetic lensing. This theory of space has explained bore hole anomalies, supermassive black hole masses in spherical galaxies and globular clusters, flat rotation curves of spiral galaxies, and other gravitational anomalies. The theory has two constants, $G$ and $alpha$, where the bore hole experiments show that $alpha approx 1/137$ is the fine structure constant.

Considerations for design of a Fourier transform mass spectrometer in the 4.2 K cold bore of a superconducting magnet.

Science.gov (United States)

O'Connor, Peter B

2002-01-01

An external source Fourier transform mass spectrometer (FTMS) constructed inside the vertical cold bore of a superconducting magnet will have dramatic advantages in effective magnetic field, noise figures, and base pressure over current commercially available external source FTMS systems. There are substantial, but solvable, difficulties in the design, primarily with regard to control of the helium boiloff rate to an acceptable level, as well as relatively minor design challenges with heat sinks, contraction of metallic ion optic elements in the extreme temperature, and tandem mass spectrometry experiments. However, the ability to construct the FTMS inside the narrow bore tube of existing, commercially available vertical bore NMR magnets will allow access to the upper magnetic field limit currently used by 900 MHz (21 Tesla) - 1 GHz (23.3 Tesla) NMR experiments. The vacuum system, simply by being held inside the cold bore at 4.2 K, will cryopump itself dropping base pressures substantially, and heat sinking the input resistor of the preamplifier to this cryogenically cooled vacuum chamber will allow reduction of the input Johnson noise by a factor of 8.4 with associated 8.4-fold improvement in signal/noise, sensitivity, and dynamic range. The simultaneous improvement of three fundamental limiting factors in the FTMS (field strength, base pressure, and Johnson noise figure) will clearly outweigh the concomitant increased helium boiloff rate particularly if this rate can be dropped to the estimated <5 L/day range. The additional use of modern cryorefrigerators will further reduce helium boiloff to zero except during MS(n) experiments and system cooldown. Copyright 2002 John Wiley & Sons, Ltd.

Aspiration of Breast Abscess through Wide Bore 14-Gauge Intravenous Cannula

International Nuclear Information System (INIS)

Afridi, S. P.; Alam, S. N.; Ainuddin, S.

2014-01-01

Objective: To aspirate breast abscess through a wide bore (14-gauge) intravenous (I/V) cannula and determine its efficacy in terms of the number of recurrences and number of aspirations. Study Design: Case series. Place and Duration of Study: Dow University of Health Sciences and Civil Hospital and Bantva Hospital, Karachi, Pakistan, from January 2009 to December 2011. Methodology: Patients with breast abscesses confirmed on ultrasound without skin ulceration were selected. The soft area of breast abscess with positive fluctuation was marked and fixed with index finger and thumb. A 14-gauge cannula was inserted. Pus was aspirated through a 50 cc syringe, repeated till no aspirate could be obtained. All patients were followed weekly for 4 weeks, clinically for size of lump, local tenderness and temperature, while complete resolution was confirmed on ultrasound, as resolution of the lesion. Results: A total of 55 patients were included in this study. Mean age was 29 +- 5.58 years while ranging from 20 - 40 years. Complete resolution of abscess was seen in 31 (56.4%) cases by single aspiration. Second aspiration was required in 24 (43.6%) patients and third aspiration in single setting was required in one case only. Recurrence after the second aspiration occurred in 08 (14.5%). Incision drainage was required in 7 (12.7%) patients. Conclusion: Percutaneous aspiration of breast abscess through a wide bore (14-gauge) I/V cannula is a simple alternative to incision and drainage. (author)

Monopole Black Hole Skyrmions

OpenAIRE

Moss, Ian G; Shiiki, N; Winstanley, E

2000-01-01

Charged black hole solutions with pion hair are discussed. These can be\\ud used to study monopole black hole catalysis of proton decay.\\ud There also exist\\ud multi-black hole skyrmion solutions with BPS monopole behaviour.

Very deep borehole. Deutag's opinion on boring, canister emplacement and retrievability

Energy Technology Data Exchange (ETDEWEB)

Harrison, Tim [Well Engineering Partners BV, The Hague (Netherlands)

2000-05-01

An engineering feasibility study has been carried out to determine whether or not it is possible to drill the proposed Very Deep Borehole concept wells required by SKB for nuclear waste disposal. A conceptual well design has been proposed. All aspects of well design have been considered, including drilling tools, rig design, drilling fluids, casing design and annulus isolation. The proposed well design is for 1168.4 mm hole to be drilled to 500 m. A 1066.8 mm outer diameter (OD) casing will be run and cemented. A 1016 mm hole will be drilled to approximately 2000 m, where 914.4 mm OD casing will be run. This annulus will be sealed with bentonite slurry apart from the bottom 100 m which will be cemented. 838.2 mm hole will be drilled to a final depth of 4000 m, where 762 mm OD slotted casing will be run. All the hole sections will be drilled using a downhole hammer with foam as the drilling fluid medium. Prior to running each casing string, the hole will be displaced to mud to assist with casing running and cementing. The waste canisters will be run on a simple J-slot tool, with integral backup system in case the J-slot fails. The canisters will all be centralised. Canisters can be retrieved using the same tool as used to run them. Procedures are given for both running and retrieving. Logging and testing is recommended only in the exploratory wells, in a maximum hole size of 311.1 mm. This will require the drilling of pilot holes to enable logging and testing to take place. It is estimated that each well will take approximately 137 days to drill and case, at an estimated cost of 4.65 Meuro per well. This time and cost estimate does not include any logging, testing, pilot hole drilling or time taken to run the canisters. New technology developments to enhance the drilling process are required in recyclable foam systems, in hammer bit technology, and in the development of robust under-reamers. It is the authors conclusion that it is possible to drill the well with

Very deep borehole. Deutag's opinion on boring, canister emplacement and retrievability

International Nuclear Information System (INIS)

Harrison, Tim

2000-05-01

An engineering feasibility study has been carried out to determine whether or not it is possible to drill the proposed Very Deep Borehole concept wells required by SKB for nuclear waste disposal. A conceptual well design has been proposed. All aspects of well design have been considered, including drilling tools, rig design, drilling fluids, casing design and annulus isolation. The proposed well design is for 1168.4 mm hole to be drilled to 500 m. A 1066.8 mm outer diameter (OD) casing will be run and cemented. A 1016 mm hole will be drilled to approximately 2000 m, where 914.4 mm OD casing will be run. This annulus will be sealed with bentonite slurry apart from the bottom 100 m which will be cemented. 838.2 mm hole will be drilled to a final depth of 4000 m, where 762 mm OD slotted casing will be run. All the hole sections will be drilled using a downhole hammer with foam as the drilling fluid medium. Prior to running each casing string, the hole will be displaced to mud to assist with casing running and cementing. The waste canisters will be run on a simple J-slot tool, with integral backup system in case the J-slot fails. The canisters will all be centralised. Canisters can be retrieved using the same tool as used to run them. Procedures are given for both running and retrieving. Logging and testing is recommended only in the exploratory wells, in a maximum hole size of 311.1 mm. This will require the drilling of pilot holes to enable logging and testing to take place. It is estimated that each well will take approximately 137 days to drill and case, at an estimated cost of 4.65 Meuro per well. This time and cost estimate does not include any logging, testing, pilot hole drilling or time taken to run the canisters. New technology developments to enhance the drilling process are required in recyclable foam systems, in hammer bit technology, and in the development of robust under-reamers. It is the authors conclusion that it is possible to drill the well with

Skyrmion black hole hair: Conservation of baryon number by black holes and observable manifestations

Energy Technology Data Exchange (ETDEWEB)

Dvali, Gia [Arnold Sommerfeld Center, Ludwig-Maximilians-Universität, 80333 München (Germany); Max-Planck-Institut für Physik, Werner-Heisenberg-Institut, 80805 München (Germany); Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Gußmann, Alexander, E-mail: alexander.gussmann@physik.uni-muenchen.de [Arnold Sommerfeld Center, Ludwig-Maximilians-Universität, 80333 München (Germany)

2016-12-15

We show that the existence of black holes with classical skyrmion hair invalidates standard proofs that global charges, such as the baryon number, cannot be conserved by a black hole. By carefully analyzing the standard arguments based on a Gedankenexperiment in which a black hole is seemingly-unable to return the baryon number that it swallowed, we identify inconsistencies in this reasoning, which does not take into the account neither the existence of skyrmion black holes nor the baryon/skyrmion correspondence. We then perform a refined Gedankenexperiment by incorporating the new knowledge and show that no contradiction with conservation of baryon number takes place at any stage of black hole evolution. Our analysis also indicates no conflict between semi-classical black holes and the existence of baryonic gauge interaction arbitrarily-weaker than gravity. Next, we study classical cross sections of a minimally-coupled massless probe scalar field scattered by a skyrmion black hole. We investigate how the skyrmion hair manifests itself by comparing this cross section with the analogous cross section caused by a Schwarzschild black hole which has the same ADM mass as the skyrmion black hole. Here we find an order-one difference in the positions of the characteristic peaks in the cross sections. The peaks are shifted to smaller scattering angles when the skyrmion hair is present. This comes from the fact that the skyrmion hair changes the near horizon geometry of the black hole when compared to a Schwarzschild black hole with same ADM mass. We keep the study of this second aspect general so that the qualitative results which we obtain can also be applied to black holes with classical hair of different kind.

Entropy of quasiblack holes

International Nuclear Information System (INIS)

Lemos, Jose P. S.; Zaslavskii, Oleg B.

2010-01-01

We trace the origin of the black hole entropy S, replacing a black hole by a quasiblack hole. Let the boundary of a static body approach its own gravitational radius, in such a way that a quasihorizon forms. We show that if the body is thermal with the temperature taking the Hawking value at the quasihorizon limit, it follows, in the nonextremal case, from the first law of thermodynamics that the entropy approaches the Bekenstein-Hawking value S=A/4. In this setup, the key role is played by the surface stresses on the quasihorizon and one finds that the entropy comes from the quasihorizon surface. Any distribution of matter inside the surface leads to the same universal value for the entropy in the quasihorizon limit. This can be of some help in the understanding of black hole entropy. Other similarities between black holes and quasiblack holes such as the mass formulas for both objects had been found previously. We also discuss the entropy for extremal quasiblack holes, a more subtle issue.

Stress concentration factors for pressurized elliptic crossbores in blocks

International Nuclear Information System (INIS)

Badr, Elie A.

2006-01-01

Intersecting bore geometries are used in a number of industrial applications including heavy-walled pressure vessels containing oil holes for lubrication, ports for valves and fluid ends of reciprocating pumps. The bore intersection location is a stress concentration point where the maximum hoop stress can be many times the fluid pressure in the bores. Intersecting circular holes in heavy-walled cylinders and rectangular blocks have been extensively investigated. Specifically, stress/pressure concentration curves for intersecting circular bores in rectangular blocks were presented by Sorem et al. [Sorem JR, Shadley JR, Tipton SM. Design curves for maximum stresses in blocks containing pressurized bore intersections. ASME J Mech Des 1990; 113: 427-31.]. However, stress/pressure concentrations due to intersecting elliptic bores have not been broadly investigated. With the availability of computer numerical control (CNC) machinery, bores with elliptic crosssection can be produced with relative ease. In this paper, hoop stress concentration ratios are developed for elliptic crossbores in rectangular blocks. Results indicate that introducing elliptic crossbores, rather than circular ones, significantly reduces the hoop stress concentration factor at the crossbore intersection. Also, the presence of intersecting crossbores has a major effect on the fatigue life of pressure vessels [Badr EA, Sorem JR, Jr Tipton SM. Evaluation of the autofrettage effect on fatigue lives of steel blocks with crossbores using a statistical and a strain-based method. ASTM J Test Eval 2000; 28: 181-8.] and the reduction of hoop stress concentration is expected to enhance the fatigue life of pressure vessels containing crossbores

Black holes without firewalls

Science.gov (United States)

Larjo, Klaus; Lowe, David A.; Thorlacius, Larus

2013-05-01

The postulates of black hole complementarity do not imply a firewall for infalling observers at a black hole horizon. The dynamics of the stretched horizon, that scrambles and reemits information, determines whether infalling observers experience anything out of the ordinary when entering a large black hole. In particular, there is no firewall if the stretched horizon degrees of freedom retain information for a time of the order of the black hole scrambling time.

Apparatus for Leak Testing Pressurized Hoses

Science.gov (United States)

Underwood, Steve D. (Inventor); Garrison, Steve G. (Inventor); Gant, Bobby D. (Inventor); Palmer, John R. (Inventor)

2015-01-01

A hose-attaching apparatus for leak-testing a pressurized hose may include a hose-attaching member. A bore may extend through the hose-attaching member. An internal annular cavity may extend coaxially around the bore. At least one of a detector probe hole and a detector probe may be connected to the internal annular cavity. At least a portion of the bore may have a diameter which is at least one of substantially equal to and less than a diameter of a hose to be leak-tested.

The effect of particle-hole interaction on the XPS core-hole spectrum

International Nuclear Information System (INIS)

Ohno, Masahide; Sjoegren, Lennart

2004-01-01

How the effective particle-hole interaction energy, U, or the polarization effect on a secondary electron in a final two-hole one-particle (2h1p) state created by the Coster-Kronig (CK) transition can solely affect the density of the CK particle states and consequently the core-hole spectral function, is discussed. The X-ray photoelectron spectroscopy (XPS) core-hole spectrum is predominantly governed by the unperturbed initial core-hole energy relative to the zero-point energy. At the latter energy, the real part of the initial core-hole self-energy becomes zero (no relaxation energy shift) and the imaginary part (the lifetime broadening) approximately maximizes. The zero-point energy relative to the double-ionization threshold energy is governed by the ratio of U relative to the bandwidth of the CK continuum. As an example, we study the 5p XPS spectra of atomic Ra (Z=88), Th (Z=90) and U (Z=92). The spectra are interpreted in terms of the change in the unperturbed initial core-hole energy relative to the zero-point energy. We explain why in general an ab initio atomic many-body calculation can provide an overall good description of solid-state spectra predominantly governed by the atomic-like localized core-hole dynamics. We explain this in terms of the change from free atom to metal in both U and the zero-point energy (self-energy)

Over spinning a black hole?

Energy Technology Data Exchange (ETDEWEB)

Bouhmadi-Lopez, Mariam; Cardoso, Vitor; Nerozzi, Andrea; Rocha, Jorge V, E-mail: mariam.bouhmadi@ist.utl.pt, E-mail: vitor.cardoso@ist.utl.pt, E-mail: andrea.nerozzi@ist.utl.pt, E-mail: jorge.v.rocha@ist.utl.pt [CENTRA, Department de Fisica, Instituto Superior Tecnico, Av. Rovisco Pais 1, 1049 Lisboa (Portugal)

2011-09-22

A possible process to destroy a black hole consists on throwing point particles with sufficiently large angular momentum into the black hole. In the case of Kerr black holes, it was shown by Wald that particles with dangerously large angular momentum are simply not captured by the hole, and thus the event horizon is not destroyed. Here we reconsider this gedanken experiment for black holes in higher dimensions. We show that this particular way of destroying a black hole does not succeed and that Cosmic Censorship is preserved.

Accreting Black Holes

OpenAIRE

Begelman, Mitchell C.

2014-01-01

I outline the theory of accretion onto black holes, and its application to observed phenomena such as X-ray binaries, active galactic nuclei, tidal disruption events, and gamma-ray bursts. The dynamics as well as radiative signatures of black hole accretion depend on interactions between the relatively simple black-hole spacetime and complex radiation, plasma and magnetohydrodynamical processes in the surrounding gas. I will show how transient accretion processes could provide clues to these ...

Naked black holes

International Nuclear Information System (INIS)

Horowitz, G.T.; Ross, S.F.

1997-01-01

It is shown that there are large static black holes for which all curvature invariants are small near the event horizon, yet any object which falls in experiences enormous tidal forces outside the horizon. These black holes are charged and near extremality, and exist in a wide class of theories including string theory. The implications for cosmic censorship and the black hole information puzzle are discussed. copyright 1997 The American Physical Society

Ballistic hole magnetic microscopy

NARCIS (Netherlands)

Haq, E.; Banerjee, T.; Siekman, M.H.; Lodder, J.C.; Jansen, R.

2005-01-01

A technique to study nanoscale spin transport of holes is presented: ballistic hole magnetic microscopy. The tip of a scanning tunneling microscope is used to inject hot electrons into a ferromagnetic heterostructure, where inelastic decay creates a distribution of electron-hole pairs.

Optimization of large bore gas engine

International Nuclear Information System (INIS)

Laiminger, S.

1999-01-01

This doctoral thesis is concerned with the experimental part of combustion optimization of a large bore gas engine. Nevertheless there was a very close co-operation with the simultaneous numeric simulation. The terms of reference were a systematic investigation of the optimization potential of the current combustion mode with the objective target to get a higher brake efficiency and lower NO x emissions. In a second part a new combustion mode for fuels containing H 2 , for fuels with very low heating value and for special fuels should be developed. The optimization contained all relevant components of the engine to achieve a stable and well suited combustion with short duration even with very lean mixture. After the optimization the engine was running stable with substantial lower NO x emissions. It was world-wide the first time when a gas medium-sized engine could reach a total electrical efficiency of more than 40 percent. Finally a combustion mode for gaseous fuels containing H 2 was developed. The engine is running now with direct ignition and with prechamber ignition. Both modes reach approximately the same efficiency and thermodynamic stability. (author)

Joint analysis of refraction seismic survey with multilevel hydrophone measurement (application for detecting the high velocity thin lid); Kussekiho jishin tansa data to kochu hydrophone data no fukugo kaiseki no rei

Energy Technology Data Exchange (ETDEWEB)

Mori, S; Harada, T; Hayashi, K [OYO Corp., Tokyo (Japan)

1996-05-01

During a refraction seismic survey conducted at a spot where a high-speed lava layer is supposedly concealed, the distribution of lava layer was estimated, and a composite analysis involving the vibration data received via hydrophones arranged in a bore hole was accomplished using a high-speed model based on an assumed geological section. The refraction survey centered on the bore hole and was accomplished using 250m-long traverse lines extending therefrom, one to the upstream and the other to the downstream of a river, producing a total length of 500m. The hydrophones were installed in the bore hole, and the measurement was carried out in an offset VSP-like observation pattern. In the analysis, the velocities obtained by the refraction survey and velocity logging were assigned to each layer on the basis of the assumed geological section for the construction of a velocity distribution model, which served as the early model for the repetition of calculation. Calculation was repeated with help of the said model, and a geological structure, capable of explaining the travel time data collected during the refraction survey and velocity logging, was successfully estimated. 1 ref., 5 figs.

Black-hole driven winds

International Nuclear Information System (INIS)

Punsly, B.M.

1988-01-01

This dissertation is a study of the physical mechanism that allows a large scale magnetic field to torque a rapidly rotating, supermassive black hole. This is an interesting problem as it has been conjectured that rapidly rotating black holes are the central engines that power the observed extragalactic double radio sources. Axisymmetric solutions of the curved space-time version of Maxwell's equations in the vacuum do not torque black holes. Plasma must be introduced for the hole to mechanically couple to the field. The dynamical aspect of rotating black holes that couples the magnetic field to the hole is the following. A rotating black hole forces the external geometry of space-time to rotate (the dragging of inertial frames). Inside of the stationary limit surface, the ergosphere, all physical particle trajectories must appear to rotate in the same direction as the black hole as viewed by the stationary observers at asymptotic infinity. In the text, it is demonstrated how plasma that is created on field lines that thread both the ergosphere and the equatorial plane will be pulled by gravity toward the equator. By the aforementioned properties of the ergosphere, the disk must rotate. Consequently, the disk acts like a unipolar generator. It drives a global current system that supports the toroidal magnetic field in an outgoing, magnetically dominated wind. This wind carries energy (mainly in the form of Poynting flux) and angular momentum towards infinity. The spin down of the black hole is the ultimate source of this energy and angular momentum flux

North American Lauraceae: terpenoid emissions, relative attraction and boring preferences of redbay ambrosia beetle, Xyleborus glabratus (coleoptera: curculionidae: scolytinae.

Directory of Open Access Journals (Sweden)

Paul E Kendra

Full Text Available The invasive redbay ambrosia beetle, Xyleborus glabratus, is the primary vector of Raffaelea lauricola, a symbiotic fungus and the etiologic agent of laurel wilt. This lethal disease has caused severe mortality of redbay (Persea borbonia and swampbay (P. palustris trees in the southeastern USA, threatens avocado (P. americana production in Florida, and has potential to impact additional New World species. To date, all North American hosts of X. glabratus and suscepts of laurel wilt are members of the family Lauraceae. This comparative study combined field tests and laboratory bioassays to evaluate attraction and boring preferences of female X. glabratus using freshly-cut bolts from nine species of Lauraceae: avocado (one cultivar of each botanical race, redbay, swampbay, silkbay (Persea humilis, California bay laurel (Umbellularia californica, sassafras (Sassafras albidum, northern spicebush (Lindera benzoin, camphor tree (Cinnamomum camphora, and lancewood (Nectandra coriacea. In addition, volatile collections and gas chromatography-mass spectroscopy (GC-MS were conducted to quantify terpenoid emissions from test bolts, and electroantennography (EAG was performed to measure olfactory responses of X. glabratus to terpenoids identified by GC-MS. Significant differences were observed among treatments in both field and laboratory tests. Silkbay and camphor tree attracted the highest numbers of the beetle in the field, and lancewood and spicebush the lowest, whereas boring activity was greatest on silkbay, bay laurel, swampbay, and redbay, and lowest on lancewood, spicebush, and camphor tree. The Guatemalan cultivar of avocado was more attractive than those of the other races, but boring response among the three was equivalent. The results suggest that camphor tree may contain a chemical deterrent to boring, and that different cues are associated with host location and host acceptance. Emissions of α-cubebene, α-copaene, α-humulene, and

North American Lauraceae: terpenoid emissions, relative attraction and boring preferences of redbay ambrosia beetle, Xyleborus glabratus (coleoptera: curculionidae: scolytinae).

Science.gov (United States)

Kendra, Paul E; Montgomery, Wayne S; Niogret, Jerome; Pruett, Grechen E; Mayfield, Albert E; MacKenzie, Martin; Deyrup, Mark A; Bauchan, Gary R; Ploetz, Randy C; Epsky, Nancy D

2014-01-01

The invasive redbay ambrosia beetle, Xyleborus glabratus, is the primary vector of Raffaelea lauricola, a symbiotic fungus and the etiologic agent of laurel wilt. This lethal disease has caused severe mortality of redbay (Persea borbonia) and swampbay (P. palustris) trees in the southeastern USA, threatens avocado (P. americana) production in Florida, and has potential to impact additional New World species. To date, all North American hosts of X. glabratus and suscepts of laurel wilt are members of the family Lauraceae. This comparative study combined field tests and laboratory bioassays to evaluate attraction and boring preferences of female X. glabratus using freshly-cut bolts from nine species of Lauraceae: avocado (one cultivar of each botanical race), redbay, swampbay, silkbay (Persea humilis), California bay laurel (Umbellularia californica), sassafras (Sassafras albidum), northern spicebush (Lindera benzoin), camphor tree (Cinnamomum camphora), and lancewood (Nectandra coriacea). In addition, volatile collections and gas chromatography-mass spectroscopy (GC-MS) were conducted to quantify terpenoid emissions from test bolts, and electroantennography (EAG) was performed to measure olfactory responses of X. glabratus to terpenoids identified by GC-MS. Significant differences were observed among treatments in both field and laboratory tests. Silkbay and camphor tree attracted the highest numbers of the beetle in the field, and lancewood and spicebush the lowest, whereas boring activity was greatest on silkbay, bay laurel, swampbay, and redbay, and lowest on lancewood, spicebush, and camphor tree. The Guatemalan cultivar of avocado was more attractive than those of the other races, but boring response among the three was equivalent. The results suggest that camphor tree may contain a chemical deterrent to boring, and that different cues are associated with host location and host acceptance. Emissions of α-cubebene, α-copaene, α-humulene, and calamenene were

Black holes are hot

International Nuclear Information System (INIS)

Gibbons, G.

1976-01-01

Recent work, which has been investigating the use of the concept of entropy with respect to gravitating systems, black holes and the universe as a whole, is discussed. The resulting theory of black holes assigns a finite temperature to them -about 10 -7 K for ordinary black holes of stellar mass -which is in complete agreement with thermodynamical concepts. It is also shown that black holes must continuously emit particles just like ordinary bodies which have a certain temperature. (U.K.)

Intermediate-Mass Black Holes

Science.gov (United States)

Miller, M. Coleman; Colbert, E. J. M.

2004-01-01

The mathematical simplicity of black holes, combined with their links to some of the most energetic events in the universe, means that black holes are key objects for fundamental physics and astrophysics. Until recently, it was generally believed that black holes in nature appear in two broad mass ranges: stellar-mass (M~3 20 M⊙), which are produced by the core collapse of massive stars, and supermassive (M~106 1010 M⊙), which are found in the centers of galaxies and are produced by a still uncertain combination of processes. In the last few years, however, evidence has accumulated for an intermediate-mass class of black holes, with M~102 104 M⊙. If such objects exist they have important implications for the dynamics of stellar clusters, the formation of supermassive black holes, and the production and detection of gravitational waves. We review the evidence for intermediate-mass black holes and discuss future observational and theoretical work that will help clarify numerous outstanding questions about these objects.

Three-dimensional rail-current distribution near the armature of simple, square-bore, two-rail railguns

International Nuclear Information System (INIS)

Beno, J.H.

1991-01-01

In this paper vector potential is solved as a three dimensional, boundary value problem for a conductor geometry consisting of square-bore railgun rails and a stationary armature. Conductors are infinitely conducting and perfect contact is assumed between rails and the armature. From the vector potential solution, surface current distribution is inferred

Design of an RF Antenna for a Large-Bore, High Power, Steady State Plasma Processing Chamber for Material Separation

International Nuclear Information System (INIS)

Rasmussen, D.A.; Freeman, R.L.

2001-01-01

The purpose of this Cooperative Research and Development Agreement (CRADA) between UT-Battelle, LLC, (Contractor), and Archimedes Technology Group, (Participant) is to evaluate the design of an RF antenna for a large-bore, high power, steady state plasma processing chamber for material separation. Criteria for optimization will be to maximize the power deposition in the plasma while operating at acceptable voltages and currents in the antenna structure. The project objectives are to evaluate the design of an RF antenna for a large-bore, high power, steady state plasma processing chamber for material separation. Criteria for optimization will be to maximize the power deposition in the plasma while operating at acceptable voltages and currents in the antenna structure

Black hole multiplicity at particle colliders (Do black holes radiate mainly on the brane?)

International Nuclear Information System (INIS)

Cavaglia, Marco

2003-01-01

If gravity becomes strong at the TeV scale, we may have the chance to produce black holes at particle colliders. In this Letter we revisit some phenomenological signatures of black hole production in TeV-gravity theories. We show that the bulk-to-brane ratio of black hole energy loss during the Hawking evaporation phase depends crucially on the black hole greybody factors and on the particle degrees of freedom. Since the greybody factors have not yet been calculated in the literature, and the particle content at trans-Planckian energies is not known, it is premature to claim that the black hole emits mainly on the brane. We also revisit the decay time and the multiplicity of the decay products of black hole evaporation. We give general formulae for black hole decay time and multiplicity. We find that the number of particles produced during the evaporation phase may be significantly lower than the average multiplicity which has been used in the past literature

String-Corrected Black Holes

Energy Technology Data Exchange (ETDEWEB)

Hubeny, V.

2005-01-12

We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect--the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive. The magnitude of this effect is related to the size of the compactification manifold.

Boring but important: a self-transcendent purpose for learning fosters academic self-regulation.

Science.gov (United States)

Yeager, David S; Henderson, Marlone D; Paunesku, David; Walton, Gregory M; D'Mello, Sidney; Spitzer, Brian J; Duckworth, Angela Lee

2014-10-01

Many important learning tasks feel uninteresting and tedious to learners. This research proposed that promoting a prosocial, self-transcendent purpose could improve academic self-regulation on such tasks. This proposal was supported in 4 studies with over 2,000 adolescents and young adults. Study 1 documented a correlation between a self-transcendent purpose for learning and self-reported trait measures of academic self-regulation. Those with more of a purpose for learning also persisted longer on a boring task rather than giving in to a tempting alternative and, many months later, were less likely to drop out of college. Study 2 addressed causality. It showed that a brief, one-time psychological intervention promoting a self-transcendent purpose for learning could improve high school science and math grade point average (GPA) over several months. Studies 3 and 4 were short-term experiments that explored possible mechanisms. They showed that the self-transcendent purpose manipulation could increase deeper learning behavior on tedious test review materials (Study 3), and sustain self-regulation over the course of an increasingly boring task (Study 4). More self-oriented motives for learning--such as the desire to have an interesting or enjoyable career--did not, on their own, consistently produce these benefits (Studies 1 and 4). 2014 APA, all rights reserved

Safety precautions of Dover Channel Tunnel boring machine; Kaitei tonneru kussakuki to anzen

Energy Technology Data Exchange (ETDEWEB)

Kondo, Y.; Fujioka, K. [Kawasaki Heavy Industries Ltd., Kobe (Japan)

1995-02-15

In May 6th 1994, the Dover Channel Tunnel referred to the largest project in this century has been opened for traffic. France and England, which have been separated by the strait with a width of about 38 km, have been connected through the submarine railway tunnel and became to be a land continuation. Since Napoleon the first, who conquested European Continent, has made a tunnel construction plan towards England, in really 27th planning, the Eurotunnel, which has been a dream in Europe for 200 years, was realized. A position of this tunnel is at a depth of 100 m under marine surface, and a geology of the strait part is a chalk layer with a calcium carbonate as a main component. For a tunnel excavation, 6 units in England side, and 5 units in France side, and therefore total 11 units of tunnel boring machines were used. Out of them, in 2 tunnels for train from France side, 2 units of tunnel boring machine (TBM) made in Japan were used. In this paper a structure and excavation method of TBM was explained, and a safety countermeasure of TBM adopted in this project was outlined. 1 ref., 10 figs.

D Modelling of Tunnel Excavation Using Pressurized Tunnel Boring Machine in Overconsolidated Soils

Science.gov (United States)

Demagh, Rafik; Emeriault, Fabrice

2013-06-01

The construction of shallow tunnels in urban areas requires a prior assessment of their effects on the existing structures. In the case of shield tunnel boring machines (TBM), the various construction stages carried out constitute a highly three-dimensional problem of soil/structure interaction and are not easy to represent in a complete numerical simulation. Consequently, the tunnelling- induced soil movements are quite difficult to evaluate. A 3D simulation procedure, using a finite differences code, namely FLAC3D, taking into account, in an explicit manner, the main sources of movements in the soil mass is proposed in this paper. It is illustrated by the particular case of Toulouse Subway Line B for which experimental data are available and where the soil is saturated and highly overconsolidated. A comparison made between the numerical simulation results and the insitu measurements shows that the 3D procedure of simulation proposed is relevant, in particular regarding the adopted representation of the different operations performed by the tunnel boring machine (excavation, confining pressure, shield advancement, installation of the tunnel lining, grouting of the annular void, etc). Furthermore, a parametric study enabled a better understanding of the singular behaviour origin observed on the ground surface and within the solid soil mass, till now not mentioned in the literature.

Video studies of passage by Anopheles gambiae mosquitoes through holes in a simulated bed net: effects of hole size, hole orientation and net environment.

Science.gov (United States)

Sutcliffe, James; Colborn, Kathryn L

2015-05-13

Holes in netting provide potential routes for mosquitoes to enter ITNs. Despite this, there is little information on how mosquitoes respond to holes in bed nets and how their responses are affected by hole size, shape and orientation or by ambient conditions around the net. Female Anopheles gambiae (G3) were recorded in a simulated bed net consisting of two sizes of untreated netting-covered behavioural arenas placed above and beside (to simulate the bed net roof and sides respectively) the experimenter who was a source of host cues from 'inside' the net. A round hole of 9 mm or 13 mm diameter was cut into the centre of the netting of each arena. Videos of unfed female mosquitoes in arenas were analysed for time spent flying, walking and standing still and for exit through the hole. The effects of the experimenter on temperature and relative humidity around the simulated net were also measured. Mosquitoes were significantly more active in overhead arenas than in arenas to the side. Hole passage was significantly more likely in smaller arenas than larger ones and for larger holes than smaller ones. In arenas to the side, hole passage rate through small holes was about 50% less likely than what could be explained by area alone. Passage rate through holes in overhead arenas was consistent with hole area. Temperature in arenas did not strongly reflect the experimenter's presence in the simulated net. Relative humidity and absolute humidity in overhead arenas, but not in arenas to the side, were immediately affected by experimenter presence. Higher levels of activity in overhead arenas than in arenas to the side were likely due to the rising heat and humidity plume from the experimenter. Lower than expected passage rates through smaller vertically oriented holes may have been be due to an edge effect that does not apply to horizontally oriented holes. Results suggest that current methods of assessing the importance of physical damage to ITNs may not accurately reflect

Structural differences between glycosylated, disulfide-linked heterodimeric Knob-into-Hole Fc fragment and its homodimeric Knob-Knob and Hole-Hole side products.

Science.gov (United States)

Kuglstatter, A; Stihle, M; Neumann, C; Müller, C; Schaefer, W; Klein, C; Benz, J

2017-09-01

An increasing number of bispecific therapeutic antibodies are progressing through clinical development. The Knob-into-Hole (KiH) technology uses complementary mutations in the CH3 region of the antibody Fc fragment to achieve heavy chain heterodimerization. Here we describe the X-ray crystal structures of glycosylated and disulfide-engineered heterodimeric KiH Fc fragment and its homodimeric Knob-Knob and Hole-Hole side products. The heterodimer structure confirms the KiH design principle and supports the hypothesis that glycosylation stabilizes a closed Fc conformation. Both homodimer structures show parallel Fc fragment architectures, in contrast to recently reported crystal structures of the corresponding aglycosylated Fc fragments which in the absence of disulfide mutations show an unexpected antiparallel arrangement. The glycosylated Knob-Knob Fc fragment is destabilized as indicated by variability in the relative orientation of its CH3 domains. The glycosylated Hole-Hole Fc fragment shows an unexpected intermolecular disulfide bond via the introduced Y349C Hole mutation which results in a large CH3 domain shift and a new CH3-CH3 interface. The crystal structures of glycosylated, disulfide-linked KiH Fc fragment and its Knob-Knob and Hole-Hole side products reported here will facilitate further design of highly efficient antibody heterodimerization strategies. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Internal structure of black holes

International Nuclear Information System (INIS)

Cvetic, Mirjam

2013-01-01

Full text: We review recent progress that sheds light on the internal structure of general black holes. We first summarize properties of general multi-charged rotating black holes both in four and five dimensions. We show that the asymptotic boundary conditions of these general asymptotically flat black holes can be modified such that a conformal symmetry emerges. These subtracted geometries preserve the thermodynamic properties of the original black holes and are of the Lifshitz type, thus describing 'a black hole in the asymptotically conical box'. Recent efforts employ solution generating techniques to construct interpolating geometries between the original black hole and their subtracted geometries. Upon lift to one dimension higher, these geometries lift to AdS 3 times a sphere, and thus provide a microscopic interpretation of the black hole entropy in terms of dual two-dimensional conformal field theory. (author)

The necessity and application of stratigraphic borings in hydrogeologic site assessments

International Nuclear Information System (INIS)

Sciacca, J.

1991-01-01

The siting and placement of monitoring wells is one of the most critical elements in hydrogeologic assessments of contaminated sites. Monitoring wells are placed to collect hydraulic and chemical concentration data to: (1) determine potential groundwater flow paths and rates: (2) analyze the nature and extent of chemical constituents in groundwater; and (3) estimate contaminant fate and transport. In many instances monitoring wells provide inappropriate or erroneous hydraulic data, do not provide coverage of potential high permeability flow pathways (such as channel sands) or may themselves create (through improper construction) a vertical conduit for contaminant flow from low permeability to high permeability units. This problem is commonly due to installing monitoring wells before conducting essential stratigraphic analysis and formulating a depositional model for the site area. This paper presents case examples where stratigraphic borings were drilled and logged in the vicinity of proposed well locations to effectively design and install the monitoring well network. The borings were continuously sampled or geophysically logged to provide a vertical profile of the borehole. In addition, the geophysical logs provided curve signatures which allowed interpretation of depositional facies. These data were used to interpret subsurface stratigraphy and effectively position monitoring wells that achieve the above objectives and prevent problems associated with faulty well positioning. This method may cost more initially. However, these initial costs are cheaper than long-term project expenses for abandoning improperly completed wells. subsequently installing supplemental monitoring wells or modifying poorly designed treatment systems which resulted from improper or insufficient data generated from the initial monitoring network

What is black hole?

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. What is black hole? Possible end phase of a star: A star is a massive, luminous ball of plasma having continuous nuclear burning. Star exhausts nuclear fuel →. White Dwarf, Neutron Star, Black Hole. Black hole's gravitational field is so powerful that even ...

Quantum effects in black holes

International Nuclear Information System (INIS)

Frolov, V.P.

1979-01-01

A strict definition of black holes is presented and some properties with regard to their mass are enumerated. The Hawking quantum effect - the effect of vacuum instability in the black hole gravitational field, as a result of shich the black hole radiates as a heated body is analyzed. It is shown that in order to obtain results on the black hole radiation it is sufficient to predetermine the in-vacuum state at a time moment in the past, when the collapsing body has a large size, and its gravitational field can be neglected. The causes and the place of particle production by the black hole, and also the space-time inside the black hole, are considered

30 CFR 57.7055 - Intersecting holes.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Intersecting holes. 57.7055 Section 57.7055... Jet Piercing Drilling-Surface and Underground § 57.7055 Intersecting holes. Holes shall not be drilled where there is a danger of intersecting a misfired hole or a hole containing explosives, blasting agents...

30 CFR 56.7055 - Intersecting holes.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Intersecting holes. 56.7055 Section 56.7055... Piercing Drilling § 56.7055 Intersecting holes. Holes shall not be drilled where there is a danger of intersecting a misfired hole or a hole containing explosives blasting agents, or detonators. [56 FR 46508, Sept...

Load-deflection characteristics of small-bore insulated-pipe clamps

International Nuclear Information System (INIS)

Severud, L.K.; Clark, G.L.

1981-12-01

The special insulated clamps used on both FFTF and CRBR piping utilize a Belleville spring arrangement to compensate for pipe thermal expansion. Analysis indicates that this produces a non-linear, directionally sensitive clamp spring rate. Since these spring rates influence the seismic response of a supported piping system, it was deemed necessary to evaluate them further by test. This has been accomplished for the FFTF clamps. A more standard insulated pipe clamp, which does not incorporate Belleville springs to accommodate thermal expansion, was also tested. This type clamp is simple in design, and economically attractive. It may have wide application prospects for use in LMFBR small bore auxiliary piping operating at temperatures below 427 0 C. Load deflection tests were conducted on 2.54 CM and 7.62 CM diameter samples of these commercial clamps

Lifshitz topological black holes

International Nuclear Information System (INIS)

Mann, R.B.

2009-01-01

I find a class of black hole solutions to a (3+1) dimensional theory gravity coupled to abelian gauge fields with negative cosmological constant that has been proposed as the dual theory to a Lifshitz theory describing critical phenomena in (2+1) dimensions. These black holes are all asymptotic to a Lifshitz fixed point geometry and depend on a single parameter that determines both their area (or size) and their charge. Most of the solutions are obtained numerically, but an exact solution is also obtained for a particular value of this parameter. The thermodynamic behaviour of large black holes is almost the same regardless of genus, but differs considerably for small black holes. Screening behaviour is exhibited in the dual theory for any genus, but the critical length at which it sets in is genus-dependent for small black holes.

Black hole decay as geodesic motion

International Nuclear Information System (INIS)

Gupta, Kumar S.; Sen, Siddhartha

2003-01-01

We show that a formalism for analyzing the near-horizon conformal symmetry of Schwarzschild black holes using a scalar field probe is capable of describing black hole decay. The equation governing black hole decay can be identified as the geodesic equation in the space of black hole masses. This provides a novel geometric interpretation for the decay of black holes. Moreover, this approach predicts a precise correction term to the usual expression for the decay rate of black holes

High-Pressure Hot-Gas Self-Acting Floating Ring Shaft Seal for Liquid Rocket Turbopumps. [tapered bore seals

Science.gov (United States)

Burcham, R. E.; Diamond, W. A.

1980-01-01

Design analysis, detail design, fabrication, and experimental evaluation was performed on two self acting floating ring shaft seals for a rocket engine turbopump high pressure 24132500 n/sq m (3500 psig) hot gas 533 K 9500 F) high speed 3142 rad/sec (30000 rmp) turbine. The initial design used Rayleigh step hydrodynamic lift pads to assist in centering the seal ring with minimum rubbing contact. The final design used a convergent tapered bore to provide hydrostatic centering force. The Rayleigh step design was tested for 107 starts and 4.52 hours total. The leakage was satisfactory; however, the design was not acceptable due to excessive wear caused by inadequate centering force and failure of the sealing dam caused by erosion damage. The tapered bore design was tested for 370 starts and 15.93 hours total. Satisfactory performance for the required life of 7.5 hours per seal was successfully demonstrated.

Acceleration of black hole universe

Science.gov (United States)

Zhang, T. X.; Frederick, C.

2014-01-01

Recently, Zhang slightly modified the standard big bang theory and developed a new cosmological model called black hole universe, which is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain all observations of the universe. Previous studies accounted for the origin, structure, evolution, expansion, and cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This paper investigates acceleration of the black hole universe and provides an alternative explanation for the redshift and luminosity distance measurements of type Ia supernovae. The results indicate that the black hole universe accelerates its expansion when it accretes the ambient matter in an increasing rate. In other words, i.e., when the second-order derivative of the mass of the black hole universe with respect to the time is positive . For a constant deceleration parameter , we can perfectly explain the type Ia supernova measurements with the reduced chi-square to be very close to unity, χ red˜1.0012. The expansion and acceleration of black hole universe are driven by external energy.

Super-horizon primordial black holes

International Nuclear Information System (INIS)

Harada, Tomohiro; Carr, B.J.

2005-01-01

We discuss a new class of solutions to the Einstein equations which describe a primordial black hole (PBH) in a flat Friedmann background. Such solutions arise if a Schwarzschild black hole is patched onto a Friedmann background via a transition region. They are possible providing the black hole event horizon is larger than the cosmological apparent horizon. Such solutions have a number of strange features. In particular, one has to define the black hole and cosmological horizons carefully and one then finds that the mass contained within the black hole event horizon decreases when the black hole is larger than the Friedmann cosmological apparent horizon, although its area always increases. These solutions involve two distinct future null infinities and are interpreted as the conversion of a white hole into a black hole. Although such solutions may not form from gravitational collapse in the same way as standard PBHs, there is nothing unphysical about them, since all energy and causality conditions are satisfied. Their conformal diagram is a natural amalgamation of the Kruskal diagram for the extended Schwarzschild solution and the conformal diagram for a black hole in a flat Friedmann background. In this paper, such solutions are obtained numerically for a spherically symmetric universe containing a massless scalar field, but it is likely that they exist for more general matter fields and less symmetric systems

NASA Observatory Confirms Black Hole Limits

Science.gov (United States)

2005-02-01

The very largest black holes reach a certain point and then grow no more, according to the best survey to date of black holes made with NASA's Chandra X-ray Observatory. Scientists have also discovered many previously hidden black holes that are well below their weight limit. These new results corroborate recent theoretical work about how black holes and galaxies grow. The biggest black holes, those with at least 100 million times the mass of the Sun, ate voraciously during the early Universe. Nearly all of them ran out of 'food' billions of years ago and went onto a forced starvation diet. Focus on Black Holes in the Chandra Deep Field North Focus on Black Holes in the Chandra Deep Field North On the other hand, black holes between about 10 and 100 million solar masses followed a more controlled eating plan. Because they took smaller portions of their meals of gas and dust, they continue growing today. "Our data show that some supermassive black holes seem to binge, while others prefer to graze", said Amy Barger of the University of Wisconsin in Madison and the University of Hawaii, lead author of the paper describing the results in the latest issue of The Astronomical Journal (Feb 2005). "We now understand better than ever before how supermassive black holes grow." One revelation is that there is a strong connection between the growth of black holes and the birth of stars. Previously, astronomers had done careful studies of the birthrate of stars in galaxies, but didn't know as much about the black holes at their centers. DSS Optical Image of Lockman Hole DSS Optical Image of Lockman Hole "These galaxies lose material into their central black holes at the same time that they make their stars," said Barger. "So whatever mechanism governs star formation in galaxies also governs black hole growth." Astronomers have made an accurate census of both the biggest, active black holes in the distance, and the relatively smaller, calmer ones closer by. Now, for the first

Sintering of beryllium oxide with 3-4 per cent elemental boron; Frittage de l'oxyde de beryllium a 3 et 5 pour cent de bore element

Energy Technology Data Exchange (ETDEWEB)

Pointud, R; Rispal, Ch; Le Garec, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

In order to manufacture a baffle absorbing neutrons of various energies, there was developed or mixture of a slower and an absorber. It is made by hot pressing impure beryllium containing boron carbide. The dense briquette has 100 x 100 x 50 mm and is machined on all her faces. She is of 2,85 density and about 3 to 4 per cent porosity, according to 5 per cent of boron. Difference of boron amount is lower than ten per cent between any two points of the briquette. (author) [French] Pour fabriquer un ecran absorbeur des neutrons d'energies diverses, on a realise l'association d'un element ralentisseur, Ie beryllium, et d'un element absorbant, le bore, par frittage sous charge d'une poudre mixte contenant de l'oxyde de beryllium technique et du carbure de bore technique. Le comprime obtenu est une brique de 100 x 100 x 50 mm, usinee sur toutes sur toutes surfaces, d'une densite de 2,85, porosite d'environ 3 a 4 pour cent pour une teneur en bore de 5 pour cent. L'heterogeneite en bore entre les differents points de cette brique est inferieure a 10 pour cent. (auteur)

A bayesian nework based risk model for volume loss in soft soils in mechanized bored tunnels

NARCIS (Netherlands)

Chivatá Cárdenas, Ibsen; Al-Jibouri, Saad H.S.; Halman, Johannes I.M.

2012-01-01

Volume loss is one of the most important risks when boring a tunnel. This is particularly true when a tunnel is being constructed in soft soils. The risk of excessive volume loss, if materialised can lead to large consequences such as damage in buildings on the surface. This paper describes the

Green's tensor calculations of plasmon resonances of single holes and hole pairs in thin gold films

International Nuclear Information System (INIS)

Alegret, Joan; Kaell, Mikael; Johansson, Peter

2008-01-01

We present numerical calculations of the plasmon properties of single-hole and hole-pair structures in optically thin gold films obtained with the Green's tensor formalism for stratified media. The method can be used to obtain the optical properties of a given hole system, without problems associated with the truncation of the infinite metal film. The calculations are compared with previously published experimental data and an excellent agreement is found. In particular, the calculations are shown to reproduce the evolution of the hole plasmon resonance spectrum as a function of hole diameter, film thickness and hole separation.

Curvature invariant characterization of event horizons of four-dimensional black holes conformal to stationary black holes

Science.gov (United States)

McNutt, David D.

2017-11-01

We introduce three approaches to generate curvature invariants that transform covariantly under a conformal transformation of a four-dimensional spacetime. For any black hole conformally related to a stationary black hole, we show how a set of conformally covariant invariants can be combined to produce a conformally covariant invariant that detects the event horizon of the conformally related black hole. As an application we consider the rotating dynamical black holes conformally related to the Kerr-Newman-Unti-Tamburino-(anti)-de Sitter spacetimes and construct an invariant that detects the conformal Killing horizon along with a second invariant that detects the conformal stationary limit surface. In addition, we present necessary conditions for a dynamical black hole to be conformally related to a stationary black hole and apply these conditions to the ingoing Kerr-Vaidya and Vaidya black hole solutions to determine if they are conformally related to stationary black holes for particular choices of the mass function. While two of the three approaches cannot be generalized to higher dimensions, we discuss the existence of a conformally covariant invariant that will detect the event horizon for any higher dimensional black hole conformally related to a stationary black hole which admits at least two conformally covariant invariants, including all vacuum spacetimes.

SU-E-J-03: Characterization of the Precision and Accuracy of a New, Preclinical, MRI-Guided Focused Ultrasound System for Image-Guided Interventions in Small-Bore, High-Field Magnets

International Nuclear Information System (INIS)

Ellens, N; Farahani, K

2015-01-01

Purpose: MRI-guided focused ultrasound (MRgFUS) has many potential and realized applications including controlled heating and localized drug delivery. The development of many of these applications requires extensive preclinical work, much of it in small animal models. The goal of this study is to characterize the spatial targeting accuracy and reproducibility of a preclinical high field MRgFUS system for thermal ablation and drug delivery applications. Methods: The RK300 (FUS Instruments, Toronto, Canada) is a motorized, 2-axis FUS positioning system suitable for small bore (72 mm), high-field MRI systems. The accuracy of the system was assessed in three ways. First, the precision of the system was assessed by sonicating regular grids of 5 mm squares on polystyrene plates and comparing the resulting focal dimples to the intended pattern, thereby assessing the reproducibility and precision of the motion control alone. Second, the targeting accuracy was assessed by imaging a polystyrene plate with randomly drilled holes and replicating the hole pattern by sonicating the observed hole locations on intact polystyrene plates and comparing the results. Third, the practicallyrealizable accuracy and precision were assessed by comparing the locations of transcranial, FUS-induced blood-brain-barrier disruption (BBBD) (observed through Gadolinium enhancement) to the intended targets in a retrospective analysis of animals sonicated for other experiments. Results: The evenly-spaced grids indicated that the precision was 0.11 +/− 0.05 mm. When image-guidance was included by targeting random locations, the accuracy was 0.5 +/− 0.2 mm. The effective accuracy in the four rodent brains assessed was 0.8 +/− 0.6 mm. In all cases, the error appeared normally distributed (p<0.05) in both orthogonal axes, though the left/right error was systematically greater than the superior/inferior error. Conclusions: The targeting accuracy of this device is sub-millimeter, suitable for many

SU-E-J-03: Characterization of the Precision and Accuracy of a New, Preclinical, MRI-Guided Focused Ultrasound System for Image-Guided Interventions in Small-Bore, High-Field Magnets

Energy Technology Data Exchange (ETDEWEB)

Ellens, N [Johns Hopkins University, Baltimore, Maryland (United States); Farahani, K [National Cancer Institute, Bethesda, MD (United States)

2015-06-15

Purpose: MRI-guided focused ultrasound (MRgFUS) has many potential and realized applications including controlled heating and localized drug delivery. The development of many of these applications requires extensive preclinical work, much of it in small animal models. The goal of this study is to characterize the spatial targeting accuracy and reproducibility of a preclinical high field MRgFUS system for thermal ablation and drug delivery applications. Methods: The RK300 (FUS Instruments, Toronto, Canada) is a motorized, 2-axis FUS positioning system suitable for small bore (72 mm), high-field MRI systems. The accuracy of the system was assessed in three ways. First, the precision of the system was assessed by sonicating regular grids of 5 mm squares on polystyrene plates and comparing the resulting focal dimples to the intended pattern, thereby assessing the reproducibility and precision of the motion control alone. Second, the targeting accuracy was assessed by imaging a polystyrene plate with randomly drilled holes and replicating the hole pattern by sonicating the observed hole locations on intact polystyrene plates and comparing the results. Third, the practicallyrealizable accuracy and precision were assessed by comparing the locations of transcranial, FUS-induced blood-brain-barrier disruption (BBBD) (observed through Gadolinium enhancement) to the intended targets in a retrospective analysis of animals sonicated for other experiments. Results: The evenly-spaced grids indicated that the precision was 0.11 +/− 0.05 mm. When image-guidance was included by targeting random locations, the accuracy was 0.5 +/− 0.2 mm. The effective accuracy in the four rodent brains assessed was 0.8 +/− 0.6 mm. In all cases, the error appeared normally distributed (p<0.05) in both orthogonal axes, though the left/right error was systematically greater than the superior/inferior error. Conclusions: The targeting accuracy of this device is sub-millimeter, suitable for many

Statistical mechanics of black holes

International Nuclear Information System (INIS)

Harms, B.; Leblanc, Y.

1992-01-01

We analyze the statistical mechanics of a gas of neutral and charged black holes. The microcanonical ensemble is the only possible approach to this system, and the equilibrium configuration is the one for which most of the energy is carried by a single black hole. Schwarzschild black holes are found to obey the statistical bootstrap condition. In all cases, the microcanonical temperature is identical to the Hawking temperature of the most massive black hole in the gas. U(1) charges in general break the bootstrap property. The problems of black-hole decay and of quantum coherence are also addressed

Requirements for drilling and disposal in deep boreholes; Foerutsaettningar foer borrning av och deponering i djupa borrhaal

Energy Technology Data Exchange (ETDEWEB)

Oden, Anders [QTOB, Haesselby (Sweden)

2013-09-15

In this report experience from drilling at great depth in crystalline rock is compiled based on project descriptions, articles and personal contacts. Rock mechanical effects have been analyzed. The report also describes proposals made by SKB and other agencies regarding the disposal of and closure of deep boreholes. The combination of drilling deep with large diameter in crystalline rocks have mainly occurred in various research projects, such as in the German KTB project. Through these projects and the increased interest in recent years for geothermal energy , today's equipment is expected to be used to drill 5000 m deep holes , with a hole diameter of 445 mm , in crystalline rock. Such holes could be used for the disposal of spent nuclear fuel. With the deposition technique recently described by Sandia National Laboratories in USA, SKB estimates that it might be possible to implement the disposal to 5000 m depth. Considering the actual implementation, drilling and disposal, and the far-reaching requirements on nuclear safety and radiation protection, it is considered an important risk getting stuck with the capsule-string, or part of it, above deposition zone without being able to get it loose. In conclusion, even if the drilling and the deposit would succeed there remains to verify that the drill holes with the deposited canisters meet the initial requirements and is long-term safe.

Regular black hole in three dimensions

OpenAIRE

Myung, Yun Soo; Yoon, Myungseok

2008-01-01

We find a new black hole in three dimensional anti-de Sitter space by introducing an anisotropic perfect fluid inspired by the noncommutative black hole. This is a regular black hole with two horizons. We compare thermodynamics of this black hole with that of non-rotating BTZ black hole. The first-law of thermodynamics is not compatible with the Bekenstein-Hawking entropy.

Black hole levitron

NARCIS (Netherlands)

Arsiwalla, X.D.; Verlinde, E.P.

2010-01-01

We study the problem of spatially stabilizing four dimensional extremal black holes in background electric/magnetic fields. Whilst looking for stationary stable solutions describing black holes placed in external fields we find that taking a continuum limit of Denef et al.’s multicenter

Is there life inside black holes?

International Nuclear Information System (INIS)

Dokuchaev, V I

2011-01-01

Bound inside rotating or charged black holes, there are stable periodic planetary orbits, which neither come out nor terminate at the central singularity. Stable periodic orbits inside black holes exist even for photons. These bound orbits may be defined as orbits of the third kind, following the Chandrasekhar classification of particle orbits in the black hole gravitational field. The existence domain for the third-kind orbits is rather spacious, and thus there is place for life inside supermassive black holes in the galactic nuclei. Interiors of the supermassive black holes may be inhabited by civilizations, being invisible from the outside. In principle, one can get information from the interiors of black holes by observing their white hole counterparts. (paper)

Feasibility studies of a carbon/oxygen logging tool for evaluating the CO2 content of the medium in nuclear device containment

International Nuclear Information System (INIS)

West, H.I. Jr.; Glasgow, J.E.

1983-12-01

The feasibility of using oil-well bore-hole logging techniques for assaying the carbonate content of a potential shot site has been investigated. The procedure makes use of the detection of the 4439-keV γ ray of carbon and the 6130-keV γ ray of oxygen produced by the inelastic scattering of 14-MeV neutrons in the bore-hole medium. For the needs of the containment program, a sensitivity of detection of CO 2 to less than or equal to 0.02 weight fraction must be achieved. Laboratory measurements indicate that only with considerable development effort could a tool be made that would come close to achieving this goal

Black Hole Grabs Starry Snack

Science.gov (United States)

2006-01-01

[figure removed for brevity, see original site] Poster Version This artist's concept shows a supermassive black hole at the center of a remote galaxy digesting the remnants of a star. NASA's Galaxy Evolution Explorer had a 'ringside' seat for this feeding frenzy, using its ultraviolet eyes to study the process from beginning to end. The artist's concept chronicles the star being ripped apart and swallowed by the cosmic beast over time. First, the intact sun-like star (left) ventures too close to the black hole, and its own self-gravity is overwhelmed by the black hole's gravity. The star then stretches apart (middle yellow blob) and eventually breaks into stellar crumbs, some of which swirl into the black hole (cloudy ring at right). This doomed material heats up and radiates light, including ultraviolet light, before disappearing forever into the black hole. The Galaxy Evolution Explorer was able to watch this process unfold by observing changes in ultraviolet light. The area around the black hole appears warped because the gravity of the black hole acts like a lens, twisting and distorting light.

A nonsingular rotating black hole

International Nuclear Information System (INIS)

Ghosh, Sushant G.

2015-01-01

The spacetime singularities in classical general relativity are inevitable, as predicated by the celebrated singularity theorems. However, it is a general belief that singularities do not exist in Nature and that they are the limitations of the general relativity. In the absence of a welldefined quantum gravity, models of regular black holes have been studied. We employ a probability distribution inspired mass function m(r) to replace the Kerr black hole mass M to represent a nonsingular rotating black hole that is identified asymptotically (r >> k, k > 0 constant) exactly as the Kerr-Newman black hole, and as the Kerr black hole when k = 0. The radiating counterpart renders a nonsingular generalization of Carmeli's spacetime as well as Vaidya's spacetime, in the appropriate limits. The exponential correction factor changing the geometry of the classical black hole to remove the curvature singularity can also be motivated by quantum arguments. The regular rotating spacetime can also be understood as a black hole of general relativity coupled to nonlinear electrodynamics. (orig.)

Thermodynamic theory of black holes

Energy Technology Data Exchange (ETDEWEB)

Davies, P C.W. [King' s Coll., London (UK). Dept. of Mathematics

1977-04-21

The thermodynamic theory underlying black hole processes is developed in detail and applied to model systems. It is found that Kerr-Newman black holes undergo a phase transition at a = 0.68M or Q = 0.86M, where the heat capacity has an infinite discontinuity. Above the transition values the specific heat is positive, permitting isothermal equilibrium with a surrounding heat bath. Simple processes and stability criteria for various black hole situations are investigated. The limits for entropically favoured black hole formation are found. The Nernst conditions for the third law of thermodynamics are not satisfied fully for black holes. There is no obvious thermodynamic reason why a black hole may not be cooled down below absolute zero and converted into a naked singularity. Quantum energy-momentum tensor calculations for uncharged black holes are extended to the Reissner-Nordstrom case, and found to be fully consistent with the thermodynamic picture for Q < M. For Q < M the model predicts that 'naked' collapse also produces radiation, with such intensity that the collapsing matter is entirely evaporated away before a naked singularity can form.

Erratic Black Hole Regulates Itself

Science.gov (United States)

2009-03-01

New results from NASA's Chandra X-ray Observatory have made a major advance in explaining how a special class of black holes may shut off the high-speed jets they produce. These results suggest that these black holes have a mechanism for regulating the rate at which they grow. Black holes come in many sizes: the supermassive ones, including those in quasars, which weigh in at millions to billions of times the mass of the Sun, and the much smaller stellar-mass black holes which have measured masses in the range of about 7 to 25 times the Sun's mass. Some stellar-mass black holes launch powerful jets of particles and radiation, like seen in quasars, and are called "micro-quasars". The new study looks at a famous micro-quasar in our own Galaxy, and regions close to its event horizon, or point of no return. This system, GRS 1915+105 (GRS 1915 for short), contains a black hole about 14 times the mass of the Sun that is feeding off material from a nearby companion star. As the material swirls toward the black hole, an accretion disk forms. This system shows remarkably unpredictable and complicated variability ranging from timescales of seconds to months, including 14 different patterns of variation. These variations are caused by a poorly understood connection between the disk and the radio jet seen in GRS 1915. Chandra, with its spectrograph, has observed GRS 1915 eleven times since its launch in 1999. These studies reveal that the jet in GRS 1915 may be periodically choked off when a hot wind, seen in X-rays, is driven off the accretion disk around the black hole. The wind is believed to shut down the jet by depriving it of matter that would have otherwise fueled it. Conversely, once the wind dies down, the jet can re-emerge. "We think the jet and wind around this black hole are in a sort of tug of war," said Joseph Neilsen, Harvard graduate student and lead author of the paper appearing in the journal Nature. "Sometimes one is winning and then, for reasons we don

Nonsingular black hole

Energy Technology Data Exchange (ETDEWEB)

Chamseddine, Ali H. [American University of Beirut, Physics Department, Beirut (Lebanon); I.H.E.S., Bures-sur-Yvette (France); Mukhanov, Viatcheslav [Niels Bohr Institute, Niels Bohr International Academy, Copenhagen (Denmark); Ludwig-Maximilians University, Theoretical Physics, Munich (Germany); MPI for Physics, Munich (Germany)

2017-03-15

We consider the Schwarzschild black hole and show how, in a theory with limiting curvature, the physical singularity ''inside it'' is removed. The resulting spacetime is geodesically complete. The internal structure of this nonsingular black hole is analogous to Russian nesting dolls. Namely, after falling into the black hole of radius r{sub g}, an observer, instead of being destroyed at the singularity, gets for a short time into the region with limiting curvature. After that he re-emerges in the near horizon region of a spacetime described by the Schwarzschild metric of a gravitational radius proportional to r{sub g}{sup 1/3}. In the next cycle, after passing the limiting curvature, the observer finds himself within a black hole of even smaller radius proportional to r{sub g}{sup 1/9}, and so on. Finally after a few cycles he will end up in the spacetime where he remains forever at limiting curvature. (orig.)

Review on advanced composite materials boring mechanism and tools

Science.gov (United States)

Shi, Runping; Wang, Chengyong

2011-05-01

With the rapid development of aviation and aerospace manufacturing technology, advanced composite materials represented by carbon fibre reinforced plastics (CFRP) and super hybrid composites (fibre/metal plates) are more and more widely applied. The fibres are mainly carbon fibre, boron fibre, Aramid fiber and Sic fibre. The matrixes are resin matrix, metal matrix and ceramic matrix. Advanced composite materials have higher specific strength and higher specific modulus than glass fibre reinforced resin composites of the 1st generation. They are widely used in aviation and aerospace industry due to their high specific strength, high specific modulus, excellent ductility, anticorrosion, heat-insulation, sound-insulation, shock absorption and high&low temperature resistance. They are used for radomes, inlets, airfoils(fuel tank included), flap, aileron, vertical tail, horizontal tail, air brake, skin, baseboards and tails, etc. Its hardness is up to 62~65HRC. The holes are greatly affected by the fibre laminates direction of carbon fibre reinforced composite material due to its anisotropy when drilling in unidirectional laminates. There are burrs, splits at the exit because of stress concentration. Besides there is delamination and the hole is prone to be smaller. Burrs are caused by poor sharpness of cutting edge, delamination, tearing, splitting are caused by the great stress caused by high thrust force. Poorer sharpness of cutting edge leads to lower cutting performance and higher drilling force at the same time. The present research focuses on the interrelation between rotation speed, feed, drill's geometry, drill life, cutting mode, tools material etc. and thrust force. At the same time, holes quantity and holes making difficulty of composites have also increased. It requires high performance drills which won't bring out defects and have long tool life. It has become a trend to develop super hard material tools and tools with special geometry for drilling

Bivalve wood borings of the ichnogenus Teredolites Leymerie from the Bohemian Cretaceous Basin (Upper Cretaceous, Czech Republic)

Czech Academy of Sciences Publication Activity Database

Kříž, J.; Mikuláš, Radek

2006-01-01

Roč. 13, č. 3 (2006), s. 159-174 ISSN 1042-0940 Institutional research plan: CEZ:AV0Z30130516 Keywords : Borings * Mollusca * sedimentary environment Subject RIV: EG - Zoology http://rzblx1.uni-regensburg.de/ezeit/detail.phtml?bibid=CASCR& colors =7&lang=en&jour_id=41560

Axion-dilation black holes

International Nuclear Information System (INIS)

Kallosh, R.

1993-01-01

In this talk some essential features of stringy black holes are described. The author considers charged U(1) and U(1) x U(1) four-dimensional axion-dilaton black holes. The Hawking temperature and the entropy of all solutions are shown to be simple functions of the squares of supercharges, defining the positivity bounds. Spherically symmetric and multi black hole solutions are presented. The extreme solutions with zero entropy (holons) represent a ground state of the theory and are characterized by elementary dilaton, axion, electric, and magnetic charges. The attractive gravitational and axion-dilaton force is balanced by the repulsive electromagnetic force. The author discusses the possibility of splitting of nearly extreme black holes. 11 refs

A 120 mm Bore Quadrupole for the Phase 1 LHC Upgrade

CERN Document Server

Fessia, P; Borgnolutti, F; Regis, F; Richter, D; Todesco, E

2010-01-01

The phase I LHC upgrade foresees the installation of a new final focusing for the high luminosity experiences in order to be able to focus the beams in the interaction points to b*~ 0.25 cm. Key element of this upgrade is a large bore (120 mm) superconducting quadrupole. This article proposes a magnet design that will make use of the LHC main dipole superconducting cable. Due to the schedule constraints and to the budget restrictions, it is mandatory to integrate in the design the maximum number of features successfully used during the LHC construction. This paper presents this design option and the rationales behind the several technical choices.

What Can We Learn About Black-Hole Formation from Black-Hole X-ray Binaries?

NARCIS (Netherlands)

Nelemans, G.A.

2007-01-01

I discuss the effect of the formation of a black hole on a (close) binary and show some of the current constraints that the observed properties of black hole X-ray binaries put on the formation of black holes. In particular, I discuss the evidence for and against asymmetric kicks imparted on the

Quantum capacity of quantum black holes

Science.gov (United States)

Adami, Chris; Bradler, Kamil

2014-03-01

The fate of quantum entanglement interacting with a black hole has been an enduring mystery, not the least because standard curved space field theory does not address the interaction of black holes with matter. We discuss an effective Hamiltonian of matter interacting with a black hole that has a precise analogue in quantum optics and correctly reproduces both spontaneous and stimulated Hawking radiation with grey-body factors. We calculate the quantum capacity of this channel in the limit of perfect absorption, as well as in the limit of a perfectly reflecting black hole (a white hole). We find that the white hole is an optimal quantum cloner, and is isomorphic to the Unruh channel with positive quantum capacity. The complementary channel (across the horizon) is entanglement-breaking with zero capacity, avoiding a violation of the quantum no-cloning theorem. The black hole channel on the contrary has vanishing capacity, while its complement has positive capacity instead. Thus, quantum states can be reconstructed faithfully behind the black hole horizon, but not outside. This work sheds new light on black hole complementarity because it shows that black holes can both reflect and absorb quantum states without violating the no-cloning theorem, and makes quantum firewalls obsolete.

Solid expandable systems put deepwater targets within reach

Energy Technology Data Exchange (ETDEWEB)

Perez-Roca, Eduardo [Enventure Global Technology L.L.C., Houston, TX (United States). Latin America; Fristch, Jerry [Enventure Global Technology L.L.C., Houston, TX (United States)

2008-07-01

Enabling technologies that take drilling operations to deeper objectives have made a significant impact on the practicality of many projects, especially deep water offshore targets. Increasing vertical depth and lateral reach requires adequate hole size to attain the desired objectives of the well bore. Solid expandable technology can maintain and retain hole size to address both the physical limitations and the economic feasibility of deep water operations. With each and every casing point, the potential for adequate hole size at total depth (TD) decreases. Solid expandable open hole liners and single-diameter systems reduce and eliminate, respectively, the well bore tapering that dictates hole size at TD and subsequent completion size. Successful mitigation of this tapering, whether through the entire well bore or through select zones, enables operators to gain access to previously unreachable reserves. Solid expandable systems have proven to be reliable and effective with over 1,000 installations in a myriad of conditions and environments worldwide. To date, over 115 of those applications have been in deep water environments. The current operating envelope for solid expandable systems include the deepest installation at {approx}28,750 ft (8,763 m) and the longest at 6,867 ft (2,083 m) in water depth over 3,150 ft (960 m). This record-length application consisted of an open hole liner installed and expanded in a single run. This paper will discuss the effectiveness of solid expandable systems in deep water operations and how the technology brings value to offshore projects especially when planned into the initial design. Case histories will be used to further illustrate the features, advantages, and benefits of expandable technology. In addition, this paper will examine the state of the solid expandable technology and its continuing evolution to provide even more drilling solutions. (author)

Black holes and the multiverse

International Nuclear Information System (INIS)

Garriga, Jaume; Vilenkin, Alexander; Zhang, Jun

2016-01-01

Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive black holes. The mechanism of black hole formation described in this paper is very generic and has important implications for the global structure of the universe. Baby universes inside super-critical black holes inflate eternally and nucleate bubbles of all vacua allowed by the underlying particle physics. The resulting multiverse has a very non-trivial spacetime structure, with a multitude of eternally inflating regions connected by wormholes. If a black hole population with the predicted mass spectrum is discovered, it could be regarded as evidence for inflation and for the existence of a multiverse

Black holes and the multiverse

Energy Technology Data Exchange (ETDEWEB)

Garriga, Jaume [Departament de Fisica Fonamental i Institut de Ciencies del Cosmos, Universitat de Barcelona, Marti i Franques, 1, Barcelona, 08028 Spain (Spain); Vilenkin, Alexander; Zhang, Jun, E-mail: jaume.garriga@ub.edu, E-mail: vilenkin@cosmos.phy.tufts.edu, E-mail: jun.zhang@tufts.edu [Institute of Cosmology, Tufts University, 574 Boston Ave, Medford, MA, 02155 (United States)

2016-02-01

Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive black holes. The mechanism of black hole formation described in this paper is very generic and has important implications for the global structure of the universe. Baby universes inside super-critical black holes inflate eternally and nucleate bubbles of all vacua allowed by the underlying particle physics. The resulting multiverse has a very non-trivial spacetime structure, with a multitude of eternally inflating regions connected by wormholes. If a black hole population with the predicted mass spectrum is discovered, it could be regarded as evidence for inflation and for the existence of a multiverse.

Anyon black holes

Science.gov (United States)

Aghaei Abchouyeh, Maryam; Mirza, Behrouz; Karimi Takrami, Moein; Younesizadeh, Younes

2018-05-01

We propose a correspondence between an Anyon Van der Waals fluid and a (2 + 1) dimensional AdS black hole. Anyons are particles with intermediate statistics that interpolates between a Fermi-Dirac statistics and a Bose-Einstein one. A parameter α (0 quasi Fermi-Dirac statistics for α >αc, but a quasi Bose-Einstein statistics for α quasi Bose-Einstein statistics. For α >αc and a range of values of the cosmological constant, there is, however, no event horizon so there is no black hole solution. Thus, for these values of cosmological constants, the AdS Anyon Van der Waals black holes have only quasi Bose-Einstein statistics.

ULTRAMASSIVE BLACK HOLE COALESCENCE

International Nuclear Information System (INIS)

Khan, Fazeel Mahmood; Holley-Bockelmann, Kelly; Berczik, Peter

2015-01-01

Although supermassive black holes (SMBHs) correlate well with their host galaxies, there is an emerging view that outliers exist. Henize 2-10, NGC 4889, and NGC 1277 are examples of SMBHs at least an order of magnitude more massive than their host galaxy suggests. The dynamical effects of such ultramassive central black holes is unclear. Here, we perform direct N-body simulations of mergers of galactic nuclei where one black hole is ultramassive to study the evolution of the remnant and the black hole dynamics in this extreme regime. We find that the merger remnant is axisymmetric near the center, while near the large SMBH influence radius, the galaxy is triaxial. The SMBH separation shrinks rapidly due to dynamical friction, and quickly forms a binary black hole; if we scale our model to the most massive estimate for the NGC 1277 black hole, for example, the timescale for the SMBH separation to shrink from nearly a kiloparsec to less than a parsec is roughly 10 Myr. By the time the SMBHs form a hard binary, gravitational wave emission dominates, and the black holes coalesce in a mere few Myr. Curiously, these extremely massive binaries appear to nearly bypass the three-body scattering evolutionary phase. Our study suggests that in this extreme case, SMBH coalescence is governed by dynamical friction followed nearly directly by gravitational wave emission, resulting in a rapid and efficient SMBH coalescence timescale. We discuss the implications for gravitational wave event rates and hypervelocity star production

Hydraulic and tracer experiments in the TVO research tunnel 1993- 1994

International Nuclear Information System (INIS)

Hautojaervi, A.; Ilvonen, M.; Vieno, T.; Viitanen, P.

1995-04-01

Three full-size deposition holes (diameter 1.5 m, depth 7.5 m) for spent fuel canisters in a KBS-3 type repository have been bored with a new fullface boring method in the TVO Research Tunnel. The Research Tunnel lies in the crystalline bedrock at the depth of 60 metres in the VLJ Repository for low and medium level waste. The holes are 6 metres apart. The boring tests were accompanied by comprehensive pre- and post-characterization of the rock and the bored wells. The inflow rates of groundwater in two of the three full-size holes are 6 and 20 litres/hour. The well in the middle is almost dry as expected on the basis of the pre-characterization. In the tracer tests two different tracers, a dye and a radioactive tracer, were used at the same time. The comprehensive data analysis performed showed that novel techniques (e.g. Extreme Value Estimation, EVE) can be successfully applied to determine the impulse response from the experimental results even in cases where the measured signals are disturbed. Hydraulic and tracer tests as well as visual inspection of the inflow gave clear indications of flow and transport in sparse and narrow channels. Transport velocities could be predicted with a reasonable accuracy by using a simple concept of fracture cavities determining the transport time and 'bottlenecks' causing the hydraulic resistance. The observed non-Fickian dispersion is thought to be caused by velocity differences over the channel width or by diffusion into stagnant pools in the fracture filling. (orig.) (36 refs., 67 figs., 1 tab.)

When Supermassive Black Holes Wander

Science.gov (United States)

Kohler, Susanna

2018-05-01

Are supermassive black holes found only at the centers of galaxies? Definitely not, according to a new study in fact, galaxies like the Milky Way may harbor several such monsters wandering through their midst.Collecting Black Holes Through MergersIts generally believed that galaxies are built up hierarchically, growing in size through repeated mergers over time. Each galaxy in a major merger likely hosts a supermassive black hole a black hole of millions to billions of times the mass of the Sun at its center. When a pair of galaxies merges, their supermassive black holes will often sink to the center of the merger via a process known as dynamical friction. There the supermassive black holes themselves will eventually merge in a burst of gravitational waves.Spatial distribution and velocities of wandering supermassive black holes in three of the authors simulated galaxies, shown in edge-on (left) and face-on (right) views of the galaxy disks. Click for a closer look. [Tremmel et al. 2018]But if a galaxy the size of the Milky Way was built through a history of many major galactic mergers, are we sure that all its accumulated supermassive black holes eventually merged at the galactic center? A new study suggests that some of these giants might have escaped such a fate and they now wander unseen on wide orbits through their galaxies.Black Holes in an Evolving UniverseLed by Michael Tremmel (Yale Center for Astronomy Astrophysics), a team of scientists has used data from a large-scale cosmological simulation, Romulus25, to explore the possibility of wandering supermassive black holes. The Romulus simulations are uniquely suited to track the formation and subsequent orbital motion of supermassive black holes as galactic halos are built up through mergers over the history of the universe.From these simulations, Tremmel and collaborators find an end total of 316 supermassive black holes residing within the bounds of 26 Milky-Way-mass halos. Of these, roughly a third are

Black holes: the membrane paradigm

International Nuclear Information System (INIS)

Thorne, K.S.; Price, R.H.; Macdonald, D.A.

1986-01-01

The physics of black holes is explored in terms of a membrane paradigm which treats the event horizon as a two-dimensional membrane embedded in three-dimensional space. A 3+1 formalism is used to split Schwarzschild space-time and the laws of physics outside a nonrotating hole, which permits treatment of the atmosphere in terms of the physical properties of thin slices. The model is applied to perturbed slowly or rapidly rotating and nonrotating holes, and to quantify the electric and magnetic fields and eddy currents passing through a membrane surface which represents a stretched horizon. Features of tidal gravitational fields in the vicinity of the horizon, quasars and active galalctic nuclei, the alignment of jets perpendicular to accretion disks, and the effects of black holes at the center of ellipsoidal star clusters are investigated. Attention is also given to a black hole in a binary system and the interactions of black holes with matter that is either near or very far from the event horizon. Finally, a statistical mechanics treatment is used to derive a second law of thermodynamics for a perfectly thermal atmosphere of a black hole

On the testing fast response NPP's valves of large nominal bores and high parameters

International Nuclear Information System (INIS)

Majorov, A.P.; Ostretsov, I.N.

1990-01-01

Investigation technique for valves of large norminal bores and high parameters which is based on application of simulation effect for operation and accident loadings during movement of valve lock at bench tests with medium flow rate by 100-1000 times less than during operation is given. Loading simulation technique is provided using simulator of lock loading. Investigation results are essential to make decision concerning advisability of serial production of fittings without full-scale test conducting

Increased productivity in construction of civil and mining tunnels through the use of high-capacity tunnel-boring machines and continuous belt conveyor muck haulage

Energy Technology Data Exchange (ETDEWEB)

Beatty, J.G.; Ganey, R.J.; Killingsworth, J.E. [Perini Corp., Chicago, IL (United States). US Heavy Division

1994-12-31

The use of a large diameter high production tunnel boring machine interfaced with a high capacity continuous belt conveyor system provides a highly productive and cost effective construction system for both civil and mining tunnels. Continuous advance of the tunnel boring machine for a distance of 1,000 feet (305 m) allows for very efficient operation of the system. The available cost reductions will likely prove that this approach to waste handling will make marginally viable projects economically feasible. 9 refs., 10 figs., 1 tab.

Stationary black holes: large D analysis

International Nuclear Information System (INIS)

Suzuki, Ryotaku; Tanabe, Kentaro

2015-01-01

We consider the effective theory of large D stationary black holes. By solving the Einstein equations with a cosmological constant using the 1/D expansion in near zone of the black hole we obtain the effective equation for the stationary black hole. The effective equation describes the Myers-Perry black hole, bumpy black holes and, possibly, the black ring solution as its solutions. In this effective theory the black hole is represented as an embedded membrane in the background, e.g., Minkowski or Anti-de Sitter spacetime and its mean curvature is given by the surface gravity redshifted by the background gravitational field and the local Lorentz boost. The local Lorentz boost property of the effective equation is observed also in the metric itself. In fact we show that the leading order metric of the Einstein equation in the 1/D expansion is generically regarded as a Lorentz boosted Schwarzschild black hole. We apply this Lorentz boost property of the stationary black hole solution to solve perturbation equations. As a result we obtain an analytic formula for quasinormal modes of the singly rotating Myers-Perry black hole in the 1/D expansion.

Drilling history core hole DC-8

International Nuclear Information System (INIS)

1978-10-01

Core hole DC-8 was completed in August, 1978 by Boyles Brothers Drilling Company, Spokane, Washington, under subcontract to Fenix and Scission, Inc. The hole was cored for the US Department of Energy and the Rockwell Hanford Operations' Basalt Waste Isolation Program. Fenix and Scisson, Inc. furnished the engineering, daily supervision of the core drilling activities, and geologic core logging for hole DC-8. Core hole DC-8 is located on the Hanford Site near the Wye Barricade and 50 feet northwest of rotary hole DC-7. The Hanford Site vation coordinates for DC-8 are North 14,955.94 feet and West 14,861.92 coordinates for DC-8 are North 14,955.94 feet and West 14,861.92 mean sea level. The purpose of core hole DC-8 was to core drill vertically through the basalt and interbed units for stratigraphic depth determination and core collection, and to provide a borehole for hydrologic testing and cross-hole seismic shear and pressure wave velocity studies with rotary hole DC-7. The total depth of core hole DC-8 was 4100.5 feet. Core recovery exceeded 97 percent of the total footage cored

Drilling history core hole DC-8

Energy Technology Data Exchange (ETDEWEB)

1978-10-01

Core hole DC-8 was completed in August, 1978 by Boyles Brothers Drilling Company, Spokane, Washington, under subcontract to Fenix and Scission, Inc. The hole was cored for the US Department of Energy and the Rockwell Hanford Operations' Basalt Waste Isolation Program. Fenix and Scisson, Inc. furnished the engineering, daily supervision of the core drilling activities, and geologic core logging for hole DC-8. Core hole DC-8 is located on the Hanford Site near the Wye Barricade and 50 feet northwest of rotary hole DC-7. The Hanford Site vation coordinates for DC-8 are North 14,955.94 feet and West 14,861.92 coordinates for DC-8 are North 14,955.94 feet and West 14,861.92 mean sea level. The purpose of core hole DC-8 was to core drill vertically through the basalt and interbed units for stratigraphic depth determination and core collection, and to provide a borehole for hydrologic testing and cross-hole seismic shear and pressure wave velocity studies with rotary hole DC-7. The total depth of core hole DC-8 was 4100.5 feet. Core recovery exceeded 97 percent of the total footage cored.

Particle creation by black holes

International Nuclear Information System (INIS)

Hawking, S.W.

1975-01-01

In the classical theory black holes can only absorb and not emit particles. However it is shown that quantum mechanical effects cause black holes to create and emit particles. This thermal emission leads to a slow decrease in the mass of the black hole and to its eventual disappearance: any primordial black hole of mass less than about 10 15 g would have evaporated by now. Although these quantum effects violate the classical law that the area of the event horizon of a black hole cannot decrease, there remains a Generalized Second Law: S + 1/4 A never decreases where S is the entropy of matter outside black holes and A is the sum of the surface areas of the event horizons. This shows that gravitational collapse converts the baryons and leptons in the collapsing body into entropy. It is tempting to speculate that this might be the reason why the Universe contains so much entropy per baryon. (orig.) [de

The 2002 Antarctic Ozone Hole

Science.gov (United States)

Newman, P. A.; Nash, E. R.; Douglass, A. R.; Kawa, S. R.

2003-01-01

Since 1979, the ozone hole has grown from near zero size to over 24 Million km2. This area is most strongly controlled by levels of inorganic chlorine and bromine oncentrations. In addition, dynamical variations modulate the size of the ozone hole by either cooling or warming the polar vortex collar region. We will review the size observations, the size trends, and the interannual variability of the size. Using a simple trajectory model, we will demonstrate the sensitivity of the ozone hole to dynamical forcing, and we will use these observations to discuss the size of the ozone hole during the 2002 Austral spring. We will further show how the Cly decreases in the stratosphere will cause the ozone hole to decrease by 1-1.5% per year. We will also show results from a 3-D chemical transport model (CTM) that has been continuously run since 1999. These CTM results directly show how strong dynamics acts to reduce the size of the ozone hole.

Black Hole's 1/N Hair

CERN Document Server

Dvali, Gia

2013-01-01

According to the standard view classically black holes carry no hair, whereas quantum hair is at best exponentially weak. We show that suppression of hair is an artifact of the semi-classical treatment and that in the quantum picture hair appears as an inverse mass-square effect. Such hair is predicted in the microscopic quantum description in which a black hole represents a self-sustained leaky Bose-condensate of N soft gravitons. In this picture the Hawking radiation is the quantum depletion of the condensate. Within this picture we show that quantum black hole physics is fully compatible with continuous global symmetries and that global hair appears with the strength B/N, where B is the global charge swallowed by the black hole. For large charge this hair has dramatic effect on black hole dynamics. Our findings can have interesting astrophysical consequences, such as existence of black holes with large detectable baryonic and leptonic numbers.

Black holes a very short introduction

CERN Document Server

Blundell, Katherine

2015-01-01

Black holes are a constant source of fascination to many due to their mysterious nature. Black Holes: A Very Short Introduction addresses a variety of questions, including what a black hole actually is, how they are characterized and discovered, and what would happen if you came too close to one. It explains how black holes form and grow—by stealing material that belongs to stars—as well as how many there may be in the Universe. It also explores the large black holes found in the centres of galaxies, and how black holes power quasars and lie behind other spectacular phenomena in the cosmos.

"Iron-Clad" Evidence For Spinning Black Hole

Science.gov (United States)

2003-09-01

Telltale X-rays from iron may reveal if black holes are spinning or not, according to astronomers using NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton Observatory. The gas flows and bizarre gravitational effects observed near stellar black holes are similar to those seen around supermassive black holes. Stellar black holes, in effect, are convenient `scale models' of their much larger cousins. Black holes come in at least two different sizes. Stellar black holes are between five and 20 times the mass of the Sun. At the other end of the size scale, supermassive black holes contain millions or billions times the mass of our Sun. The Milky Way contains both a supermassive black hole at its center, as well as a number of stellar black holes sprinkled throughout the Galaxy. At a press conference at the "Four Years of Chandra" symposium in Huntsville, Ala., Jon Miller of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. discussed recent results on the X-ray spectra, or distribution of X-rays with energy, from the iron atoms in gas around three stellar black holes in the Milky Way. "Discovering the high degree of correspondence between stellar and supermassive black holes is a real breakthrough," said Miller. "Because stellar black holes are smaller, everything happens about a million times faster, so they can be used as a test-bed for theories of how spinning black holes affect the space and matter around them." X-rays from a stellar black hole are produced when gas from a nearby companion star is heated to tens of millions of degrees as it swirls toward the black hole. Iron atoms in this gas produce distinctive X-ray signals that can be used to study the orbits of particles around the black hole. For example, the gravity of a black hole can shift the X-rays to lower energies. "The latest work provides the most precise measurements yet of the X-ray spectra for stellar black holes," said Miller. "These data help rule out

Biogeography of Wood-Boring Crustaceans (Isopoda: Limnoriidae) Established in European Coastal Waters

Science.gov (United States)

Borges, Luísa M. S.; Merckelbach, Lucas M.; Cragg, Simon M.

2014-01-01

Marine wood-borers of the Limnoriidae cause great destruction to wooden structures exposed in the marine environment. In this study we collated occurrence data obtained from field surveys, spanning over a period of 10 years, and from an extensive literature review. We aimed to determine which wood-boring limnoriid species are established in European coastal waters; to map their past and recent distribution in Europe in order to infer species range extension or contraction; to determine species environmental requirements using climatic envelopes. Of the six species of wood-boring Limnoria previously reported occurring in Europe, only Limnoria lignorum, L. quadripunctata and L. tripunctata are established in European coastal waters. L. carinata and L. tuberculata have uncertain established status, whereas L. borealis is not established in European waters. The species with the widest distribution in Europe is Limnoria lignorum, which is also the most tolerant species to a range of salinities. L. quadripunctata and L. tripunctata appear to be stenohaline. However, the present study shows that both L. quadripunctata and L. tripunctata are more widespread in Europe than previous reports suggested. Both species have been found occurring in Europe since they were described, and their increased distribution is probably the results of a range expansion. On the other hand L. lignorum appears to be retreating poleward with ocean warming. In certain areas (e.g. southern England, and southern Portugal), limnoriids appear to be very abundant and their activity is rivalling that of teredinids. Therefore, it is important to monitor the distribution and destructive activity of these organisms in Europe. PMID:25313796

Epiretinal proliferation in lamellar macular holes and full-thickness macular holes: clinical and surgical findings.

Science.gov (United States)

Lai, Tso-Ting; Chen, San-Ni; Yang, Chung-May

2016-04-01

To report the clinical findings and surgical outcomes of lamellar macular holes (LMH) with or without lamellar hole-associated epiretinal proliferation (LHEP), and those of full-thickness macular holes (FTMH) presenting with LHEP. From 2009 to 2013, consecutive cases of surgically treated LMH, and all FTMH cases with LHEP were reviewed, given a follow-up time over 1 year. In the LMH group (43 cases), those with LHEP (19 cases) had significantly thinner bases and larger openings than those without (24 cases). The rate of disrupted IS/OS line was higher in the LHEP subgroup preoperatively (68.4 % vs 37.5 %), but similar between subgroups postoperatively (36.8 % and 33.3 %). The preoperative and postoperative visual acuity showed no significant difference between two subgroups. In the FTMH group (13 cases), the average hole size was 219.2 ± 92.1 μm. Permanent or transient spontaneous hole closure was noted in 69.2 % of cases. An intact IS-OS line was found in only 23 % of cases at the final follow-up. In the LMH group, LHEP was associated with a more severe defect but didn't affect surgical outcomes. In the FTMH group, spontaneous hole closure was frequently noted. Despite small holes, disruption of IS-OS line was common after hole closure.

Nonextremal stringy black hole

International Nuclear Information System (INIS)

Suzuki, K.

1997-01-01

We construct a four-dimensional BPS saturated heterotic string solution from the Taub-NUT solution. It is a nonextremal black hole solution since its Euler number is nonzero. We evaluate its black hole entropy semiclassically. We discuss the relation between the black hole entropy and the degeneracy of string states. The entropy of our string solution can be understood as the microscopic entropy which counts the elementary string states without any complications. copyright 1997 The American Physical Society

Dosage of boron traces in graphite, uranium and beryllium oxide; Dosage de traces de bore dans le graphite, l'uranium et l'oxyde de beryllium

Energy Technology Data Exchange (ETDEWEB)

Coursier, J [Ecole Nationale Superieure de Physique et Chimie Industrielles, 75 - Paris (France); Hure, J; Platzer, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1955-07-01

The problem of the dosage of the boron in the materials serving to the construction of nuclear reactors arises of the following way: to determine to about 0,1 ppm close to the quantities of boron of the order of tenth ppm. We have chosen the colorimetric analysis with curcumin as method of dosage. To reach the indicated contents, it is necessary to do a previous separation of the boron and the materials of basis, either by extraction of tetraphenylarsonium fluoborate in the case of the boron dosage in uranium and the beryllium oxide, either by the use of a cations exchanger resin of in the case of graphite. (M.B.) [French] Le probleme du dosage du bore dans les materiaux servant a la construction de reacteurs nucleaires se pose de la facon suivante: determiner a environ 0,1 ppm pres des quantites de bore de l'ordre de quelques dixiemes de ppm. Nous avons choisit la colorimetrie a la curcumine comme methode de dosage. Pour atteindre les teneurs indiquees, il est necessaire d'effectuer une separation prealable du bore et des materiaux de base, soit par extraction du fluoborate de tetraphenylarsonium dans le cas du dosage de bore dans l'uranium et l'oxyde de beryllium, soit par l'utilisation d'une resine echangeuse de cations dans le cas du graphite. (M.B.)

The search for black holes

International Nuclear Information System (INIS)

Torn, K.

1976-01-01

Conceivable experimental investigations to prove the existence of black holes are discussed. Double system with a black hole turning around a star-satellite are in the spotlight. X-radiation emmited by such systems and resulting from accretion of the stellar gas by a black hole, and the gas heating when falling on the black hole might prove the model suggested. A source of strong X-radiation observed in the Cygnus star cluster and referred to as Cygnus X-1 may be thus identified as a black hole. Direct registration of short X-ray pulses with msec intervals might prove the suggestion. The lack of appropriate astrophysic facilities is pointed out to be the major difficulty on the way of experimental verifications

Stability of squashed Kaluza-Klein black holes

International Nuclear Information System (INIS)

Kimura, Masashi; Ishihara, Hideki; Murata, Keiju; Soda, Jiro

2008-01-01

The stability of squashed Kaluza-Klein black holes is studied. The squashed Kaluza-Klein black hole looks like a five-dimensional black hole in the vicinity of horizon and looks like a four-dimensional Minkowski spacetime with a circle at infinity. In this sense, squashed Kaluza-Klein black holes can be regarded as black holes in the Kaluza-Klein spacetimes. Using the symmetry of squashed Kaluza-Klein black holes, SU(2)xU(1)≅U(2), we obtain master equations for a part of the metric perturbations relevant to the stability. The analysis based on the master equations gives strong evidence for the stability of squashed Kaluza-Klein black holes. Hence, the squashed Kaluza-Klein black holes deserve to be taken seriously as realistic black holes in the Kaluza-Klein spacetime.

Black-hole bomb and superradiant instabilities

International Nuclear Information System (INIS)

Cardoso, Vitor; Dias, Oscar J.C.; Lemos, Jose P.S.; Yoshida, Shijun

2004-01-01

A wave impinging on a Kerr black hole can be amplified as it scatters off the hole if certain conditions are satisfied, giving rise to superradiant scattering. By placing a mirror around the black hole one can make the system unstable. This is the black-hole bomb of Press and Teukolsky. We investigate in detail this process and compute the growing time scales and oscillation frequencies as a function of the mirror's location. It is found that in order for the system black hole plus mirror to become unstable there is a minimum distance at which the mirror must be located. We also give an explicit example showing that such a bomb can be built. In addition, our arguments enable us to justify why large Kerr-AdS black holes are stable and small Kerr-AdS black holes should be unstable

Interior structure of rotating black holes. III. Charged black holes

International Nuclear Information System (INIS)

Hamilton, Andrew J. S.

2011-01-01

This paper extends to the case of charged rotating black holes the conformally stationary, axisymmetric, conformally separable solutions presented for uncharged rotating black holes in a companion paper. In the present paper, the collisionless fluid accreted by the black hole may be charged. The charge of the black hole is determined self-consistently by the charge accretion rate. As in the uncharged case, hyper-relativistic counterstreaming between ingoing and outgoing streams drives inflation at (just above) the inner horizon, followed by collapse. If both ingoing and outgoing streams are charged, then conformal separability holds during early inflation, but fails as inflation develops. If conformal separability is imposed throughout inflation and collapse, then only one of the ingoing and outgoing streams can be charged: the other must be neutral. Conformal separability prescribes a hierarchy of boundary conditions on the ingoing and outgoing streams incident on the inner horizon. The dominant radial boundary conditions require that the incident ingoing and outgoing number densities be uniform with latitude, but the charge per particle must vary with latitude such that the incident charge densities vary in proportion to the radial electric field. The subdominant angular boundary conditions require specific forms of the incident number- and charge-weighted angular motions. If the streams fall freely from outside the horizon, then the prescribed angular conditions can be achieved by the charged stream, but not by the neutral stream. Thus, as in the case of an uncharged black hole, the neutral stream must be considered to be delivered ad hoc to just above the inner horizon.

30 CFR 57.9360 - Shelter holes.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Shelter holes. 57.9360 Section 57.9360 Mineral....9360 Shelter holes. (a) Shelter holes shall be— (1) Provided at intervals adequate to assure the safety... farthest projection of moving equipment. (b) Shelter holes shall not be used for storage unless a 40-inch...

Turbulent black holes.

Science.gov (United States)

Yang, Huan; Zimmerman, Aaron; Lehner, Luis

2015-02-27

We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability-which is triggered above a certain perturbation amplitude threshold-akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies-a phenomenon reminiscent of the inverse cascade displayed by (2+1)-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids.

Untitled

Indian Academy of Sciences (India)

starch the heavier is the attack. The beetles enter longitudinally but bore transversely after a short distance from the entrance holes. Sen” has reported that “the entry hole of the adult beetle is carried in a zigzag fishion, more horizontal than vertical and is always found full of frass ''. 4. LIFE-HISTORY. (i) Precopulation period.

Information Retention by Stringy Black Holes

CERN Document Server

Ellis, John

2015-01-01

Building upon our previous work on two-dimensional stringy black holes and its extension to spherically-symmetric four-dimensional stringy black holes, we show how the latter retain information. A key r\\^ole is played by an infinite-dimensional $W_\\infty$ symmetry that preserves the area of an isolated black-hole horizon and hence its entropy. The exactly-marginal conformal world-sheet operator representing a massless stringy particle interacting with the black hole necessarily includes a contribution from $W_\\infty$ generators in its vertex function. This admixture manifests the transfer of information between the string black hole and external particles. We discuss different manifestations of $W_\\infty$ symmetry in black-hole physics and the connections between them.

Fast Determination of Toxic Arsenic Species in Food Samples Using Narrow-bore High-Performance Liquid-Chromatography Inductively Coupled Plasma Mass Spectrometry.

Science.gov (United States)

Terol, Amanda; Marcinkowska, Monika; Ardini, Francisco; Grotti, Marco

2016-01-01

A new method for the speciation analysis of arsenic in food using narrow-bore high-performance liquid-chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) has been developed. Fast separation of arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid was carried out in 7 min using an anion-exchange narrow-bore Nucleosil 100 SB column and 12 mM ammonium dihydrogen phosphate of pH 5.2 as the mobile phase, at a flow rate of 0.3 mL min(-1). A PFA-ST micronebulizer jointed to a cyclonic spray chamber was used for HPLC-ICP-MS coupling. Compared with standard-bore HPLC-ICP-MS, the new method has provided higher sensitivity, reduced mobile-phase consumption, a lower matrix plasma load and a shorter analysis time. The achieved instrumental limits of detection were in the 0.3 - 0.4 ng As mL(-1) range, and the precision was better than 3%. The arsenic compounds were efficiently (>80%) extracted from various food samples using a 1:5 methanol/water solution, with additional ultrasonic treatment for rice products. The applicability of this method was demonstrated by the analysis of several samples, such as seafood (fish, mussels, shrimps, edible algae) and rice-based products (Jasmine and Arborio rice, spaghetti, flour, crackers), including three certified reference materials.

Shaping Globular Clusters with Black Holes

Science.gov (United States)

Kohler, Susanna

2018-03-01

How many black holes lurk within the dense environments of globular clusters, and how do these powerful objects shape the properties of the cluster around them? One such cluster, NGC 3201, is now helping us to answer these questions.Hunting Stellar-Mass Black HolesSince the detection of merging black-hole binaries by the Laser Interferometer Gravitational-Wave Observatory (LIGO), the dense environments of globular clusters have received increasing attention as potential birthplaces of these compact binary systems.The central region of the globular star cluster NGC 3201, as viewed by Hubble. The black hole is in orbit with the star marked by the blue circle. [NASA/ESA]In addition, more and more stellar-mass black-hole candidates have been observed within globular clusters, lurking in binary pairs with luminous, non-compact companions. The most recent of these detections, found in the globular cluster NGC 3201, stands alone as the first stellar-mass black hole candidate discovered via radial velocity observations: the black holes main-sequence companion gave away its presence via a telltale wobble.Now a team of scientists led by Kyle Kremer (CIERA and Northwestern University) is using models of this system to better understand the impact that black holes might have on their host clusters.A Model ClusterThe relationship between black holes and their host clusters is complicated. Though the cluster environment can determine the dynamical evolution of the black holes, the retention rate of black holes in a globular cluster (i.e., how many remain in the cluster when they are born as supernovae, rather than being kicked out during the explosion) influences how the host cluster evolves.Kremer and collaborators track this complex relationship by modeling the evolution of a cluster similar to NGC 3201 with a Monte Carlo code. The code incorporates physics relevant to the evolution of black holes and black-hole binaries in globular clusters, such as two-body relaxation

Black holes matter

DEFF Research Database (Denmark)

Kragh, Helge Stjernholm

2016-01-01

Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015).......Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015)....

Newborn Black Holes

Science.gov (United States)

Science Teacher, 2005

2005-01-01

Scientists using NASA's Swift satellite say they have found newborn black holes, just seconds old, in a confused state of existence. The holes are consuming material falling into them while somehow propelling other material away at great speeds. "First comes a blast of gamma rays followed by intense pulses of x-rays. The energies involved are much…

30 CFR 77.1010 - Collaring holes.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Collaring holes. 77.1010 Section 77.1010... Control § 77.1010 Collaring holes. (a) Starter steels shall be used when collaring holes with hand-held drills. (b) Men shall not hold the drill steel while collaring holes, or rest their hands on the chuck or...

Statistical clustering of primordial black holes

Energy Technology Data Exchange (ETDEWEB)

Carr, B J [Cambridge Univ. (UK). Inst. of Astronomy

1977-04-01

It is shown that Meszaros theory of galaxy formation, in which galaxies form from the density perturbations associated with the statistical fluctuation in the number density of primordial black holes, must be modified if the black holes are initially surrounded by regions of lower radiation density than average (as is most likely). However, even in this situation, the sort of effect Meszaros envisages does occur and could in principle cause galactic mass-scales to bind at the conventional time. In fact, the requirement that galaxies should not form prematurely implies that black holes could not have a critical density in the mass range above 10/sup 5/ M(sun). If the mass spectrum of primordial black holes falls off more slowly than m/sup -3/ (as expected), then the biggest black holes have the largest clustering effect. In this case the black hole clustering theory of galaxy formation reduces to the black hole seed theory of galaxy formation, in which each galaxy becomes bound under the gravitational influence of a single black hole nucleus. The seed theory could be viable only if the early Universe had a soft equation of state until a time exceeding 10/sup -4/ s or if something prevented black hole formation before 1 s.

Black holes and quantum processes in them

International Nuclear Information System (INIS)

Frolov, V.P.

1976-01-01

The latest achievements in the physics of black holes are reviewed. The problem of quantum production in a strong gravitational field of black holes is considered. Another parallel discovered during investigation of interactions between black holes and between black holes and surrounding media, is also drawn with thermodynamics. A gravitational field of rotating black holes is considered. Some cosmological aspects of evaporation of small black holes are discussed as well as possibilities to observe them

Black holes and everyday physics

International Nuclear Information System (INIS)

Bekenstein, J.D.

1982-01-01

Black holes have piqued much curiosity. But thus far they have been important only in ''remote'' subjects like astrophysics and quantum gravity. It is shown that the situation can be improved. By a judicious application of black hole physics, one can obtain new results in ''everyday physics''. For example, black holes yield a quantum universal upper bound on the entropy-to-energy ratio for ordinary thermodynamical systems which was unknown earlier. It can be checked, albeit with much labor, by ordinary statistical methods. Black holes set a limitation on the number of species of elementary particles-quarks, leptons, neutrinos - which may exist. And black holes lead to a fundamental limitation on the rate at which information can be transferred for given message energy by any communication system. (author)

Black hole final state conspiracies

International Nuclear Information System (INIS)

McInnes, Brett

2009-01-01

The principle that unitarity must be preserved in all processes, no matter how exotic, has led to deep insights into boundary conditions in cosmology and black hole theory. In the case of black hole evaporation, Horowitz and Maldacena were led to propose that unitarity preservation can be understood in terms of a restriction imposed on the wave function at the singularity. Gottesman and Preskill showed that this natural idea only works if one postulates the presence of 'conspiracies' between systems just inside the event horizon and states at much later times, near the singularity. We argue that some AdS black holes have unusual internal thermodynamics, and that this may permit the required 'conspiracies' if real black holes are described by some kind of sum over all AdS black holes having the same entropy

Black hole shadow in an asymptotically flat, stationary, and axisymmetric spacetime: The Kerr-Newman and rotating regular black holes

Science.gov (United States)

Tsukamoto, Naoki

2018-03-01

The shadow of a black hole can be one of the strong observational evidences for stationary black holes. If we see shadows at the center of galaxies, we would say whether the observed compact objects are black holes. In this paper, we consider a formula for the contour of a shadow in an asymptotically-flat, stationary, and axisymmetric black hole spacetime. We show that the formula is useful for obtaining the contour of the shadow of several black holes such as the Kerr-Newman black hole and rotating regular black holes. Using the formula, we can obtain new examples of the contour of the shadow of rotating black holes if assumptions are satisfied.

K-shell-hole production, multiple-hole production, charge transfer, and antisymmetry

International Nuclear Information System (INIS)

Reading, J.F.; Ford, A.L.

1980-01-01

In calculating K-shell-hole production when an ion collides with an atom, account must be taken of the fact that processes involving electrons other than the K-shell electron can occur. For example, after making a K-shell hole an L-shell electron may be knocked into it, or an L-shell vacancy may be produced and the K-shell electron promoted to that vacancy in the ''Fermi sea'' of the target-atom orbitals. In 1973 a theorem was proved by one of the present authors demonstrating that all these multielectron processes cancel in an independent-particle model for the target atom. In this paper it is shown that the same thing occurs for hole production by charge transfer to the ion. The authors demonstrate that multihole production does not obey this simple rule and that the probability for multihole production is not the product of independent single-electron probabilities. The correct expressions that should be used for these processes are given, together with new results for charge-transfer processes accompanied by hole production

Prechamber ignition concepts for stationary large bore gas engines; Vorkammerzuendkonzepte fuer stationaer betriebene Grossgasmotoren

Energy Technology Data Exchange (ETDEWEB)

Heinz, Christoph [MTU Friedrichshafen GmbH (Germany); Kammerstaetter, Stefan; Sattelmayer, Thomas [Technische Univ. Muenchen (Germany). Lehrstuhl fuer Thermodynamik

2012-01-15

A testing facility for the optical investigation of ignition and combustion in large bore gas engines is described. The test rig was developed at the Institute of Thermodynamics at Technical University of Munich. Core element of the setup is an optically accessible high pressure combustion cell which can be charged, ignited, and discharged repeatedly according to the cycle times of a real engine. Until now the apparatus was used for the investigation of two different prechamber concepts. (orig.)

Drilling history core hole DC-4

International Nuclear Information System (INIS)

1978-12-01

Core hole DC-4 was completed at a depth of 3998 feet in December, 1978 by Boyles Brothers Drilling Company, Spokane, Washington, under subcontract to Fenix and Scission, Inc. The hole was cored for the US Department of Energy and the Rockwell Hanford Operations' Basalt Waste Isolation Program. Fenix and Sicsson, Inc. furnished the engineering, daily supervision of the cable tool and core drilling activities, and geological core logging for DC-4. Core hole DC-4 is located on the Hanford Site about 3 miles east of the Yakima Barricade and approximately 103 feet southwest of rotary hole DC-5, which was completed to 3990 feet in February, 1978. Hanford Site coordinates reported for hole DC-4 are north 49,385.62 feet and west 85,207.63 feet, and Washington State coordinates are north 454,468.73 feet and east 2,209,990.87 feet. No elevation survey is available for hole DC-4, but it is approximately 745 feet above mean sea level based upon the survey of hole DC-5, which has a reported elevation of 745.16 feet on the top of the 3-inch flange. The purpose of core hole DC-4 was to core drill vertically through the basalt and interbed units for stratigraphic depth determination and core collection, and to provide a borehole for hydrologic testing, cross-hole seismic shear, and pressure wave velocity studies with rotary hole DC-5. Hole DC-4 was drilled through the overburden into basalt bedrock by cable tool methods (0-623 feet) and continuously cored through the final interval (623 to 3998 feet).Core recovery was 95.8 percent of the total footage cored

Warped products and black holes

International Nuclear Information System (INIS)

Hong, Soon-Tae

2005-01-01

We apply the warped product space-time scheme to the Banados-Teitelboim-Zanelli black holes and the Reissner-Nordstroem-anti-de Sitter black hole to investigate their interior solutions in terms of warped products. It is shown that there exist no discontinuities of the Ricci and Einstein curvatures across event horizons of these black holes

Atomic structure in black hole

International Nuclear Information System (INIS)

Nagatani, Yukinori

2006-01-01

We propose that any black hole has atomic structure in its inside and has no horizon as a model of black holes. Our proposal is founded on a mean field approximation of gravity. The structure of our model consists of a (charged) singularity at the center and quantum fluctuations of fields around the singularity, namely, it is quite similar to that of atoms. Any properties of black holes, e.g. entropy, can be explained by the model. The model naturally quantizes black holes. In particular, we find the minimum black hole, whose structure is similar to that of the hydrogen atom and whose Schwarzschild radius is approximately 1.1287 times the Planck length. Our approach is conceptually similar to Bohr's model of the atomic structure, and the concept of the minimum Schwarzschild radius is similar to that of the Bohr radius. The model predicts that black holes carry baryon number, and the baryon number is rapidly violated. This baryon number violation can be used as verification of the model. (author)

Gamma ray bursts of black hole universe

Science.gov (United States)

Zhang, T. X.

2015-07-01

Slightly modifying the standard big bang theory, Zhang recently developed a new cosmological model called black hole universe, which has only a single postulate but is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain existing observations of the universe. In the previous studies, we have explained the origin, structure, evolution, expansion, cosmic microwave background radiation, quasar, and acceleration of black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This study investigates gamma ray bursts of black hole universe and provides an alternative explanation for the energy and spectrum measurements of gamma ray bursts according to the black hole universe model. The results indicate that gamma ray bursts can be understood as emissions of dynamic star-like black holes. A black hole, when it accretes its star or merges with another black hole, becomes dynamic. A dynamic black hole has a broken event horizon and thus cannot hold the inside hot (or high-frequency) blackbody radiation, which flows or leaks out and produces a GRB. A star when it collapses into its core black hole produces a long GRB and releases the gravitational potential energy of the star as gamma rays. A black hole that merges with another black hole produces a short GRB and releases a part of their blackbody radiation as gamma rays. The amount of energy obtained from the emissions of dynamic star-like black holes are consistent with the measurements of energy from GRBs. The GRB energy spectra derived from this new emission mechanism are also consistent with the measurements.

Simulations of nearly extremal binary black holes

Science.gov (United States)

Giesler, Matthew; Scheel, Mark; Hemberger, Daniel; Lovelace, Geoffrey; Kuper, Kevin; Boyle, Michael; Szilagyi, Bela; Kidder, Lawrence; SXS Collaboration

2015-04-01

Astrophysical black holes could have nearly extremal spins; therefore, nearly extremal black holes could be among the binaries that current and future gravitational-wave observatories will detect. Predicting the gravitational waves emitted by merging black holes requires numerical-relativity simulations, but these simulations are especially challenging when one or both holes have mass m and spin S exceeding the Bowen-York limit of S /m2 = 0 . 93 . Using improved methods we simulate an unequal-mass, precessing binary black hole coalescence, where the larger black hole has S /m2 = 0 . 99 . We also use these methods to simulate a nearly extremal non-precessing binary black hole coalescence, where both black holes have S /m2 = 0 . 994 , nearly reaching the Novikov-Thorne upper bound for holes spun up by thin accretion disks. We demonstrate numerical convergence and estimate the numerical errors of the waveforms; we compare numerical waveforms from our simulations with post-Newtonian and effective-one-body waveforms; and we compare the evolution of the black-hole masses and spins with analytic predictions.

Instability of ultra-spinning black holes

International Nuclear Information System (INIS)

Emparan, Roberto; Myers, Robert C.

2003-01-01

It has long been known that, in higher-dimensional general relativity, there are black hole solutions with an arbitrarily large angular momentum for a fixed mass. We examine the geometry of the event horizon of such ultra-spinning black holes and argue that these solutions become unstable at large enough rotation. Hence we find that higher-dimensional general relativity imposes an effective 'Kerr-bound' on spinning black holes through a dynamical decay mechanism. Our results also give indications of the existence of new stationary black holes with 'rippled' horizons of spherical topology. We consider various scenarios for the possible decay of ultra-spinning black holes, and finally discuss the implications of our results for black holes in braneworld scenarios. (author)

Braneworld black holes and entropy bounds

Directory of Open Access Journals (Sweden)

Y. Heydarzade

2018-01-01

Full Text Available The Bousso's D-bound entropy for the various possible black hole solutions on a 4-dimensional brane is checked. It is found that the D-bound entropy here is apparently different from that of obtained for the 4-dimensional black hole solutions. This difference is interpreted as the extra loss of information, associated to the extra dimension, when an extra-dimensional black hole is moved outward the observer's cosmological horizon. Also, it is discussed that N-bound entropy is hold for the possible solutions here. Finally, by adopting the recent Bohr-like approach to black hole quantum physics for the excited black holes, the obtained results are written also in terms of the black hole excited states.

Black holes new horizons

CERN Document Server

Hayward, Sean Alan

2013-01-01

Black holes, once just fascinating theoretical predictions of how gravity warps space-time according to Einstein's theory, are now generally accepted as astrophysical realities, formed by post-supernova collapse, or as supermassive black holes mysteriously found at the cores of most galaxies, powering active galactic nuclei, the most powerful objects in the universe. Theoretical understanding has progressed in recent decades with a wider realization that local concepts should characterize black holes, rather than the global concepts found in textbooks. In particular, notions such as trapping h

Quantum information erasure inside black holes

International Nuclear Information System (INIS)

Lowe, David A.; Thorlacius, Larus

2015-01-01

An effective field theory for infalling observers in the vicinity of a quasi-static black hole is given in terms of a freely falling lattice discretization. The lattice model successfully reproduces the thermal spectrum of outgoing Hawking radiation, as was shown by Corley and Jacobson, but can also be used to model observations made by a typical low-energy observer who enters the black hole in free fall at a prescribed time. The explicit short distance cutoff ensures that, from the viewpoint of the infalling observer, any quantum information that entered the black hole more than a scrambling time earlier has been erased by the black hole singularity. This property, combined with the requirement that outside observers need at least of order the scrambling time to extract quantum information from the black hole, ensures that a typical infalling observer does not encounter drama upon crossing the black hole horizon in a theory where black hole information is preserved for asymptotic observers.

Sintering of beryllium oxide with 3-4 per cent elemental boron; Frittage de l'oxyde de beryllium a 3 et 5 pour cent de bore element

Energy Technology Data Exchange (ETDEWEB)

Pointud, R.; Rispal, Ch.; Le Garec, M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

In order to manufacture a baffle absorbing neutrons of various energies, there was developed or mixture of a slower and an absorber. It is made by hot pressing impure beryllium containing boron carbide. The dense briquette has 100 x 100 x 50 mm and is machined on all her faces. She is of 2,85 density and about 3 to 4 per cent porosity, according to 5 per cent of boron. Difference of boron amount is lower than ten per cent between any two points of the briquette. (author) [French] Pour fabriquer un ecran absorbeur des neutrons d'energies diverses, on a realise l'association d'un element ralentisseur, Ie beryllium, et d'un element absorbant, le bore, par frittage sous charge d'une poudre mixte contenant de l'oxyde de beryllium technique et du carbure de bore technique. Le comprime obtenu est une brique de 100 x 100 x 50 mm, usinee sur toutes sur toutes surfaces, d'une densite de 2,85, porosite d'environ 3 a 4 pour cent pour une teneur en bore de 5 pour cent. L'heterogeneite en bore entre les differents points de cette brique est inferieure a 10 pour cent. (auteur)

Estimation of the equilibrium formation temperature in the presence of bore fluid invasion

DEFF Research Database (Denmark)

Poulsen, Søren Erbs; Nielsen, S.B.; Balling, N.

2012-01-01

from BHT measurements in the presence of bore fluid invasion. The scheme is based on finite element analysis in conjunction with Markov chain Monte Carlo inversion. The axisymmetric forward model assumes a cylindrical source of finite radius and contrasting thermal parameters, which includes...... by correction schemes based on purely conductive models. The influence of the borehole radius and fluid invasion on the temperature measured at the borehole axis attenuates over time. It is further demonstrated that the invasion radius and the matrix thermal conductivity cannot be estimated simultaneously...

Statistical Hair on Black Holes

International Nuclear Information System (INIS)

Strominger, A.

1996-01-01

The Bekenstein-Hawking entropy for certain BPS-saturated black holes in string theory has recently been derived by counting internal black hole microstates at weak coupling. We argue that the black hole microstate can be measured by interference experiments even in the strong coupling region where there is clearly an event horizon. Extracting information which is naively behind the event horizon is possible due to the existence of statistical quantum hair carried by the black hole. This quantum hair arises from the arbitrarily large number of discrete gauge symmetries present in string theory. copyright 1996 The American Physical Society

On black hole horizon fluctuations

International Nuclear Information System (INIS)

Tuchin, K.L.

1999-01-01

A study of the high angular momentum particles 'atmosphere' near the Schwarzschild black hole horizon suggested that strong gravitational interactions occur at invariant distance of the order of 3 √M [2]. We present a generalization of this result to the Kerr-Newman black hole case. It is shown that the larger charge and angular momentum black hole bears, the larger invariant distance at which strong gravitational interactions occur becomes. This invariant distance is of order 3 √((r + 2 )/((r + - r - ))). This implies that the Planckian structure of the Hawking radiation of extreme black holes is completely broken

Thermodynamics of Accelerating Black Holes.

Science.gov (United States)

Appels, Michael; Gregory, Ruth; Kubizňák, David

2016-09-23

We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon-even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability, and phase structure of these black holes.

Gamma-gamma density and lithology tools simulation based on GEANT4 advanced low energy Compton scattering (GALECS) package

International Nuclear Information System (INIS)

Esmaeili-sani, Vahid; Moussavi-zarandi, Ali; Boghrati, Behzad; Afarideh, Hossein

2012-01-01

Geophysical bore-hole data represent the physical properties of rocks, such as density and formation lithology, as a function of depth in a well. Properties of rocks are obtained from gamma ray transport logs. Transport of gamma rays, from a 137 Cs point gamma source situated in a bore-hole tool, through rock media to detectors, has been simulated using a GEANT4 radiation transport code. The advanced Compton scattering concepts were used to gain better analyses about well formation. The simulation and understanding of advanced Compton scattering highly depends on how accurately the effects of Doppler broadening and Rayleigh scattering are taken into account. A Monte Carlo package that simulates the gamma-gamma well logging tools based on GEANT4 advanced low energy Compton scattering (GALECS).

Toxic waste liquor disposal

International Nuclear Information System (INIS)

Burton, W.R.

1985-01-01

Toxic waste liquors, especially radio active liquors, are disposed in a sub-zone by feeding down a bore hole a first liquid, then a buffer liquid (e.g. water), then the toxic liquors. Pressure variations are applied to the sub-zone to mix the first liquid and liquors to form gels or solids which inhibit further mixing and form a barrier between the sub-zone and the natural waters in the environment of the sub-zone. In another example the location of the sub-zone is selected so that the environement reacts with the liquors to produce a barrier around the zone. Blind bore holes are used to monitor the sub-zone profile. Materials may be added to the liquor to enhance barrier formation. (author)

Geometry of higher-dimensional black hole thermodynamics

International Nuclear Information System (INIS)

Aaman, Jan E.; Pidokrajt, Narit

2006-01-01

We investigate thermodynamic curvatures of the Kerr and Reissner-Nordstroem (RN) black holes in spacetime dimensions higher than four. These black holes possess thermodynamic geometries similar to those in four-dimensional spacetime. The thermodynamic geometries are the Ruppeiner geometry and the conformally related Weinhold geometry. The Ruppeiner geometry for a d=5 Kerr black hole is curved and divergent in the extremal limit. For a d≥6 Kerr black hole there is no extremality but the Ruppeiner curvature diverges where one suspects that the black hole becomes unstable. The Weinhold geometry of the Kerr black hole in arbitrary dimension is a flat geometry. For the RN black hole the Ruppeiner geometry is flat in all spacetime dimensions, whereas its Weinhold geometry is curved. In d≥5 the Kerr black hole can possess more than one angular momentum. Finally we discuss the Ruppeiner geometry for the Kerr black hole in d=5 with double angular momenta

Compressibility of rotating black holes

International Nuclear Information System (INIS)

Dolan, Brian P.

2011-01-01

Interpreting the cosmological constant as a pressure, whose thermodynamically conjugate variable is a volume, modifies the first law of black hole thermodynamics. Properties of the resulting thermodynamic volume are investigated: the compressibility and the speed of sound of the black hole are derived in the case of nonpositive cosmological constant. The adiabatic compressibility vanishes for a nonrotating black hole and is maximal in the extremal case--comparable with, but still less than, that of a cold neutron star. A speed of sound v s is associated with the adiabatic compressibility, which is equal to c for a nonrotating black hole and decreases as the angular momentum is increased. An extremal black hole has v s 2 =0.9 c 2 when the cosmological constant vanishes, and more generally v s is bounded below by c/√(2).

Black holes with halos

Science.gov (United States)

Monten, Ruben; Toldo, Chiara

2018-02-01

We present new AdS4 black hole solutions in N =2 gauged supergravity coupled to vector and hypermultiplets. We focus on a particular consistent truncation of M-theory on the homogeneous Sasaki–Einstein seven-manifold M 111, characterized by the presence of one Betti vector multiplet. We numerically construct static and spherically symmetric black holes with electric and magnetic charges, corresponding to M2 and M5 branes wrapping non-contractible cycles of the internal manifold. The novel feature characterizing these nonzero temperature configurations is the presence of a massive vector field halo. Moreover, we verify the first law of black hole mechanics and we study the thermodynamics in the canonical ensemble. We analyze the behavior of the massive vector field condensate across the small-large black hole phase transition and we interpret the process in the dual field theory.

Black hole as a wormhole factory

Directory of Open Access Journals (Sweden)

Sung-Won Kim

2015-12-01

Full Text Available There have been lots of debates about the final fate of an evaporating black hole and the singularity hidden by an event horizon in quantum gravity. However, on general grounds, one may argue that a black hole stops radiation at the Planck mass (ħc/G1/2∼10−5 g, where the radiated energy is comparable to the black hole's mass. And also, it has been argued that there would be a wormhole-like structure, known as “spacetime foam”, due to large fluctuations below the Planck length (ħG/c31/2∼10−33 cm. In this paper, as an explicit example, we consider an exact classical solution which represents nicely those two properties in a recently proposed quantum gravity model based on different scaling dimensions between space and time coordinates. The solution, called “Black Wormhole”, consists of two different states, depending on its mass parameter M and an IR parameter ω: For the black hole state (with ωM2>1/2, a non-traversable wormhole occupies the interior region of the black hole around the singularity at the origin, whereas for the wormhole state (with ωM2<1/2, the interior wormhole is exposed to an outside observer as the black hole horizon is disappearing from evaporation. The black hole state becomes thermodynamically stable as it approaches the merging point where the interior wormhole throat and the black hole horizon merges, and the Hawking temperature vanishes at the exact merge point (with ωM2=1/2. This solution suggests the “Generalized Cosmic Censorship” by the existence of a wormhole-like structure which protects the naked singularity even after the black hole evaporation. One could understand the would-be wormhole inside the black hole horizon as the result of microscopic wormholes created by “negative” energy quanta which have entered the black hole horizon in Hawking radiation process; the quantum black hole could be a wormhole factory! It is found that this speculative picture may be consistent with the

Black-hole creation in quantum cosmology

Energy Technology Data Exchange (ETDEWEB)

Zhong Chao, Wu [Rome, Univ. `La Sapienza` (Italy). International Center for Relativistic Astrophysics]|[Specola Vaticana, Vatican City State (Vatican City State, Holy See)

1997-11-01

It is proven that the probability of a black hole created from the de Sitter space-time background, at the Wkb level, is the exponential of one quarter of the sum of the black hole and cosmological horizon areas, or the total entropy of the universe. This is true not only for the spherically symmetric cases of the Schwarzschild or Reissner-Nordstroem black holes, but also for the rotating cases of the Kerr black hole and the rotating charged case of the Newman black hole. The de Sitter metric is the most probable evolution at the Planckian era of the universe.

A Magnetic Resonance Imaging-Conditional External Cardiac Defibrillator for Resuscitation Within the Magnetic Resonance Imaging Scanner Bore.

Science.gov (United States)

Schmidt, Ehud J; Watkins, Ronald D; Zviman, Menekhem M; Guttman, Michael A; Wang, Wei; Halperin, Henry A

2016-10-01

Subjects undergoing cardiac arrest within a magnetic resonance imaging (MRI) scanner are currently removed from the bore and then from the MRI suite, before the delivery of cardiopulmonary resuscitation and defibrillation, potentially increasing the risk of mortality. This precludes many higher-risk (acute ischemic and acute stroke) patients from undergoing MRI and MRI-guided intervention. An MRI-conditional cardiac defibrillator should enable scanning with defibrillation pads attached and the generator ON, enabling application of defibrillation within the seconds of MRI after a cardiac event. An MRI-conditional external defibrillator may improve patient acceptance for MRI procedures. A commercial external defibrillator was rendered 1.5 Tesla MRI-conditional by the addition of novel radiofrequency filters between the generator and commercial disposable surface pads. The radiofrequency filters reduced emission into the MRI scanner and prevented cable/surface pad heating during imaging, while preserving all the defibrillator monitoring and delivery functions. Human volunteers were imaged using high specific absorption rate sequences to validate MRI image quality and lack of heating. Swine were electrically fibrillated (n=4) and thereafter defibrillated both outside and inside the MRI bore. MRI image quality was reduced by 0.8 or 1.6 dB, with the generator in monitoring mode and operating on battery or AC power, respectively. Commercial surface pads did not create artifacts deeper than 6 mm below the skin surface. Radiofrequency heating was within US Food and Drug Administration guidelines. Defibrillation was completely successful inside and outside the MRI bore. A prototype MRI-conditional defibrillation system successfully defibrillated in the MRI without degrading the image quality or increasing the time needed for defibrillation. It can increase patient acceptance for MRI procedures. © 2016 American Heart Association, Inc.

Black Holes in Higher Dimensions

Directory of Open Access Journals (Sweden)

Reall Harvey S.

2008-09-01

Full Text Available We review black-hole solutions of higher-dimensional vacuum gravity and higher-dimensional supergravity theories. The discussion of vacuum gravity is pedagogical, with detailed reviews of Myers–Perry solutions, black rings, and solution-generating techniques. We discuss black-hole solutions of maximal supergravity theories, including black holes in anti-de Sitter space. General results and open problems are discussed throughout.

Assembly and Test of HD2, a 36 mm bore high field Nb3Sn Dipole Magnet

International Nuclear Information System (INIS)

Ferracin, P.; Bingham, B.; Caspi, S.; Cheng, D.W.; Dietderich, D.R.; Felice, H.; Godeke, A.; Hafalia, A.R.; Hannaford, C.R.; Joseph, J.; Lietzke, A.F.; Lizarazo, J.; Sabbi, G.; Trillaud, F.; Wang, X.

2008-01-01

We report on the fabrication, assembly, and test of the Nb 3 Sn dipole magnet HD2. The magnet, aimed at demonstrating the application of Nb 3 Sn superconductor in high field accelerator-type dipoles, features a 36 mm clear bore surrounded by block-type coils with tilted ends. The coil design is optimized to minimize geometric harmonics in the aperture and the magnetic peak field on the conductor in the coil ends. The target bore field of 15 T at 4.3 K is consistent with critical current measurements of extracted strands. The coils are horizontally pre-stressed during assembly using an external aluminum shell pre-tensioned with water-pressurized bladders. Axial pre-loading of the coil ends is accomplished through two end plates and four aluminum tension rods. The strain in coil, shell, and rods is monitored with strain gauges during assembly, cool-down and magnet excitation, and compared with 3D finite element computations. Magnet's training performance, quench locations, and ramp-rate dependence are then analyzed and discussed.

Plasma electron hole kinematics. I. Momentum conservation

Energy Technology Data Exchange (ETDEWEB)

Hutchinson, I. H.; Zhou, C. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2016-08-15

We analyse the kinematic properties of a plasma electron hole: a non-linear self-sustained localized positive electric potential perturbation, trapping electrons, which behaves as a coherent entity. When a hole accelerates or grows in depth, ion and electron plasma momentum is changed both within the hole and outside, by an energization process we call jetting. We present a comprehensive analytic calculation of the momentum changes of an isolated general one-dimensional hole. The conservation of the total momentum gives the hole's kinematics, determining its velocity evolution. Our results explain many features of the behavior of hole speed observed in numerical simulations, including self-acceleration at formation, and hole pushing and trapping by ion streams.

Detailed design of the large-bore 8 T superconducting magnet for the NAFASSY test facility

Science.gov (United States)

Corato, V.; Affinito, L.; Anemona, A.; Besi Vetrella, U.; Di Zenobio, A.; Fiamozzi Zignani, C.; Freda, R.; Messina, G.; Muzzi, L.; Perrella, M.; Reccia, L.; Tomassetti, G.; Turtù, S.; della Corte, A.

2015-03-01

The ‘NAFASSY’ (NAtional FAcility for Superconducting SYstems) facility is designed to test wound conductor samples under high-field conditions at variable temperatures. Due to its unique features, it is reasonable to assume that in the near future NAFASSY will have a preeminent role at the international level in the qualification of long coiled cables in operative conditions. The magnetic system consists of a large warm bore background solenoid, made up of three series-connected grading sections obtained by winding three different Nb3Sn Cable-in-Conduit Conductors. Thanks to the financial support of the Italian Ministry for University and Research the low-field coil is currently under production. The design has been properly modified to allow the system to operate also as a stand-alone facility, with an inner bore diameter of 1144 mm. This magnet is able to provide about 7 T on its axis and about 8 T close to the insert inner radius, giving the possibility of performing a test relevant for large-sized NbTi or medium-field Nb3Sn conductors. The detailed design of the 8 T magnet, including the electro-magnetic, structural and thermo-hydraulic analysis, is here reported, as well as the production status.

Evolving Coronal Holes and Interplanetary Erupting Stream ...

Indian Academy of Sciences (India)

prominences, have a significantly higher rate of occurrence in the vicinity of coronal .... coronal holes due to the birth of new holes or the growth of existing holes. .... Statistics of newly formed coronal hole areas (NFOCHA) associated with ...

Quantum black holes

OpenAIRE

Hooft, G. 't

1987-01-01

This article is divided into three parts. First, a systematic derivation of the Hawking radiation is given in three different ways. The information loss problem is then discussed in great detail. The last part contains a concise discussion of black hole thermodynamics. This article was published as chapter $6$ of the IOP book "Lectures on General Relativity, Cosmology and Quantum Black Holes" (July $2017$).

Black holes and cosmic censorship

International Nuclear Information System (INIS)

Hiscock, W.A.

1979-01-01

It is widely accepted that the complete gravitational collapse of a body always yields a black hole, and that naked singularities are never produced (the cosmic censorship hypothesis). The local (or strong) cosmic censorship hypothesis states that singularities which are even locally naked (e.g., to an observer inside a black hole) are never produced. This dissertation studies the validity of these two conjectures. The Kerr-Newman metrics describes the black holes only when M 2 greater than or equal to Q 2 + P 2 , where M is the mass of the black hole, a = J/M its specific angular momentum, Q its electric charge, and P its magnetic charge. In the first part of this dissertation, the possibility of converting an extreme Kerr-Newman black hole (M 2 = a 2 + Q 2 + P 2 ) into a naked singularity by the accretion of test particles is considered. The motion of test particles is studied with a large angular momentum to energy ratio, and also test particles with a large charge to energy ratio. The final state is always found to be a black hole if the angular momentum, electric charge, and magnetic charge of the black hole are all much greater than the corresponding angular momentum, electric charge, and magnetic charge of the test particle. In Part II of this dissertation possible black hole interior solutions are studied. The Cauchy horizons and locally naked timelike singularities of the charged (and/or rotating) solutions are contrasted with the spacelike all-encompassing singularity of the Schwarzschild solution. It is determined which portions of the analytic extension of the Reissner-Nordstroem solution are relevant to realistic gravitational collapse

Instability of charged anti-de Sitter black holes

International Nuclear Information System (INIS)

Gwak, Bogeun; Lee, Bum-Hoon; Ro, Daeho

2016-01-01

We have studied the instability of charged anti-de Sitter black holes in four- or higher-dimensions under fragmentation. The unstable black holes under fragmentation can be broken into two black holes. Instability depends not only on the mass and charge of the black hole but also on the ratio between the fragmented black hole and its predecessor. We have found that the near extremal black holes are unstable, and Schwarzschild-AdS black holes are stable. These are qualitatively similar to black holes in four dimensions and higher. The detailed instabilities are numerically investigated.

Spin One Hawking Radiation from Dirty Black Holes

OpenAIRE

Petarpa Boonserm; Tritos Ngampitipan; Matt Visser

2013-01-01

A “clean” black hole is a black hole in vacuum such as the Schwarzschild black hole. However in real physical systems, there are matter fields around a black hole. Such a black hole is called a “dirty black hole”. In this paper, the effect of matter fields on the black hole and the greybody factor is investigated. The results show that matter fields make a black hole smaller. They can increase the potential energy to a black hole to obstruct Hawking radiation to propagate. This causes the gre...

Tracking black holes in numerical relativity

International Nuclear Information System (INIS)

Caveny, Scott A.; Anderson, Matthew; Matzner, Richard A.

2003-01-01

This work addresses the problem of generically tracking black hole event horizons in computational simulation of black hole interactions. Solutions of the hyperbolic eikonal equation, solved on a curved spacetime manifold containing black hole sources, are employed in development of a robust tracking method capable of continuously monitoring arbitrary changes of topology in the event horizon as well as arbitrary numbers of gravitational sources. The method makes use of continuous families of level set viscosity solutions of the eikonal equation with identification of the black hole event horizon obtained by the signature feature of discontinuity formation in the eikonal's solution. The method is employed in the analysis of the event horizon for the asymmetric merger in a binary black hole system. In this first such three dimensional analysis, we establish both qualitative and quantitative evidence for our method and its application to the asymmetric problem. We focus attention on (1) the topology of the throat connecting the holes following merger, (2) the time of merger, and (3) continuing to account for the surface of section areas of the black hole sources

Interface state generation after hole injection

International Nuclear Information System (INIS)

Zhao, C. Z.; Zhang, J. F.; Groeseneken, G.; Degraeve, R.; Ellis, J. N.; Beech, C. D.

2001-01-01

After terminating electrical stresses, the generation of interface states can continue. Our previous work in this area indicates that the interface state generation following hole injection originates from a defect. These defects are inactive in a fresh device, but can be excited by hole injection and then converted into interface states under a positive gate bias after hole injection. There is little information available on these defects. This article investigates how they are formed and attempts to explain why they are sensitive to processing conditions. Roles played by hydrogen and trapped holes will be clarified. A detailed comparison between the interface state generation after hole injection in air and that in forming gas is carried out. Our results show that there are two independent processes for the generation: one is caused by H 2 cracking and the other is not. The rate limiting process for the interface state generation after hole injection is discussed and the relation between the defects responsible for this generation and hole traps is explored. [copyright] 2001 American Institute of Physics

Testing quantum gravity through dumb holes

Energy Technology Data Exchange (ETDEWEB)

Pourhassan, Behnam, E-mail: b.pourhassan@du.ac.ir [School of Physics, Damghan University, Damghan (Iran, Islamic Republic of); Faizal, Mir, E-mail: f2mir@uwaterloo.ca [Department of Physics and Astronomy, University of Lethbridge, Lethbridge, AB T1K 3M4 (Canada); Irving K. Barber School of Arts and Sciences, University of British Columbia - Okanagan, Kelowna, BC V1V 1V7 (Canada); Capozziello, Salvatore, E-mail: capozzie@na.infn.it [Dipartimento di Fisica, Università di Napoli ”Frederico II” Complesso Universitario di Monte S. Angelo, Edificio G, Via Cinthia, I-80126 Napoli (Italy); Gran Sasso Science Institute (INFN), Via F. Crispi 7, I-67100 L’ Aquila (Italy)

2017-02-15

We propose a method to test the effects of quantum fluctuations on black holes by analyzing the effects of thermal fluctuations on dumb holes, the analogs for black holes. The proposal is based on the Jacobson formalism, where the Einstein field equations are viewed as thermodynamical relations, and so the quantum fluctuations are generated from the thermal fluctuations. It is well known that all approaches to quantum gravity generate logarithmic corrections to the entropy of a black hole and the coefficient of this term varies according to the different approaches to the quantum gravity. It is possible to demonstrate that such logarithmic terms are also generated from thermal fluctuations in dumb holes. In this paper, we claim that it is possible to experimentally test such corrections for dumb holes, and also obtain the correct coefficient for them. This fact can then be used to predict the effects of quantum fluctuations on realistic black holes, and so it can also be used, in principle, to experimentally test the different approaches to quantum gravity.

Black Hole Paradoxes

International Nuclear Information System (INIS)

Joshi, Pankaj S.; Narayan, Ramesh

2016-01-01

We propose here that the well-known black hole paradoxes such as the information loss and teleological nature of the event horizon are restricted to a particular idealized case, which is the homogeneous dust collapse model. In this case, the event horizon, which defines the boundary of the black hole, forms initially, and the singularity in the interior of the black hole at a later time. We show that, in contrast, gravitational collapse from physically more realistic initial conditions typically leads to the scenario in which the event horizon and space-time singularity form simultaneously. We point out that this apparently simple modification can mitigate the causality and teleological paradoxes, and also lends support to two recently suggested solutions to the information paradox, namely, the ‘firewall’ and ‘classical chaos’ proposals. (paper)

Merging Black Holes

Science.gov (United States)

Centrella, Joan

2012-01-01

The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as future. space-based detectors. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on.the resulting 'gold rush' of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics

BOOK REVIEW: Introduction to Black Hole Physics Introduction to Black Hole Physics

Science.gov (United States)

Tanaka, Takahiro

2012-07-01

Introduction to Black Hole Physics is a large volume (504 pages), and yet despite this it is still really an introductory text. The book gives an introduction to general relativity, but most of the text is dedicated to attracting the reader's attention to the interesting world of black hole physics. In this sense, the book is very distinct from other textbooks on general relativity. We are told that it was based on the lectures given by Professor Frolov, one of the authors, over the last 30 years. One can obtain the basic ideas about black holes, and also the necessary tips to understand general relativity at a very basic level. For example, in the discussion about particle motion in curved space, the authors start with a brief review on analytical mechanics. The book does not require its readers to have a great deal of knowledge in advance. If you are familiar with such a basic subject, you can simply omit that section. The reason why I especially picked up on this topic as an example is that the book devotes a significant number of pages to geodesic motions in black hole spacetime. One of the main motivations to study black holes is related to how they will actually be observed, once we develop the ability to observe them clearly. The book does explain such discoveries as, for instance, how the motion of a particle is related to a beautiful mathematical structure arising from the hidden symmetry of spacetime, which became transparent via the recent progress in the exploration of black holes in higher dimensions; a concise introduction to this latest topic is deferred to Appendix D, so as not to distract the reader with its mathematical complexities. It should be also mentioned that the book is not limited to general relativistic aspects: quantum fields on a black hole background and Hawking radiation are also covered. Also included are current hot topics, for instance the gravitational waves from a system including black holes, whose first direct detection is

Magnetohydrodynamics near a black hole

International Nuclear Information System (INIS)

Wilson, J.R.

1975-01-01

A numerical computer study of hydromagnetic flow near a black hole is presented. First, the equations of motion are developed to a form suitable for numerical computations. Second, the results of calculations describing the magnetic torques exerted by a rotating black hole on a surrounding magnetic plasma and the electric charge that is induced on the surface of the black hole are presented. (auth)

What is a black hole

International Nuclear Information System (INIS)

Tipler, F.J.

1979-01-01

A definition of a black hole is proposed that should work in any stably causal space-time. This is that a black hole is the closure of the smaller future set that contains all noncosmological trapped surfaces and which has its boundary generated by null geodesic segments that are boundary generators of TIPs. This allows precise definitions of cosmic censorship and white holes. (UK)

Black holes escaping from domain walls

International Nuclear Information System (INIS)

Flachi, Antonino; Sasaki, Misao; Pujolas, Oriol; Tanaka, Takahiro

2006-01-01

Previous studies concerning the interaction of branes and black holes suggested that a small black hole intersecting a brane may escape via a mechanism of reconnection. Here we consider this problem by studying the interaction of a small black hole and a domain wall composed of a scalar field and simulate the evolution of this system when the black hole acquires an initial recoil velocity. We test and confirm previous results, however, unlike the cases previously studied, in the more general set-up considered here, we are able to follow the evolution of the system also during the separation, and completely illustrate how the escape of the black hole takes place

Black Holes Have Simple Feeding Habits

Science.gov (United States)

2008-06-01

The biggest black holes may feed just like the smallest ones, according to data from NASA’s Chandra X-ray Observatory and ground-based telescopes. This discovery supports the implication of Einstein's relativity theory that black holes of all sizes have similar properties, and will be useful for predicting the properties of a conjectured new class of black holes. The conclusion comes from a large observing campaign of the spiral galaxy M81, which is about 12 million light years from Earth. In the center of M81 is a black hole that is about 70 million times more massive than the Sun, and generates energy and radiation as it pulls gas in the central region of the galaxy inwards at high speed. In contrast, so-called stellar mass black holes, which have about 10 times more mass than the Sun, have a different source of food. These smaller black holes acquire new material by pulling gas from an orbiting companion star. Because the bigger and smaller black holes are found in different environments with different sources of material to feed from, a question has remained about whether they feed in the same way. Using these new observations and a detailed theoretical model, a research team compared the properties of M81's black hole with those of stellar mass black holes. The results show that either big or little, black holes indeed appear to eat similarly to each other, and produce a similar distribution of X-rays, optical and radio light. AnimationMulti-wavelength Images of M81 One of the implications of Einstein's theory of General Relativity is that black holes are simple objects and only their masses and spins determine their effect on space-time. The latest research indicates that this simplicity manifests itself in spite of complicated environmental effects. "This confirms that the feeding patterns for black holes of different sizes can be very similar," said Sera Markoff of the Astronomical Institute, University of Amsterdam in the Netherlands, who led the study

Entropy of black holes with multiple horizons

Science.gov (United States)

He, Yun; Ma, Meng-Sen; Zhao, Ren

2018-05-01

We examine the entropy of black holes in de Sitter space and black holes surrounded by quintessence. These black holes have multiple horizons, including at least the black hole event horizon and a horizon outside it (cosmological horizon for de Sitter black holes and "quintessence horizon" for the black holes surrounded by quintessence). Based on the consideration that the two horizons are not independent each other, we conjecture that the total entropy of these black holes should not be simply the sum of entropies of the two horizons, but should have an extra term coming from the correlations between the two horizons. Different from our previous works, in this paper we consider the cosmological constant as the variable and employ an effective method to derive the explicit form of the entropy. We also try to discuss the thermodynamic stabilities of these black holes according to the entropy and the effective temperature.

Black hole entropy, curved space and monsters

International Nuclear Information System (INIS)

Hsu, Stephen D.H.; Reeb, David

2008-01-01

We investigate the microscopic origin of black hole entropy, in particular the gap between the maximum entropy of ordinary matter and that of black holes. Using curved space, we construct configurations with entropy greater than the area A of a black hole of equal mass. These configurations have pathological properties and we refer to them as monsters. When monsters are excluded we recover the entropy bound on ordinary matter S 3/4 . This bound implies that essentially all of the microstates of a semiclassical black hole are associated with the growth of a slightly smaller black hole which absorbs some additional energy. Our results suggest that the area entropy of black holes is the logarithm of the number of distinct ways in which one can form the black hole from ordinary matter and smaller black holes, but only after the exclusion of monster states

Bosonic instability of charged black holes

International Nuclear Information System (INIS)

Gaina, A.B.; Ternov, I.M.

1986-01-01

The processes of spontaneous and induced production and accumulation of charged bosons on quasibound superradiant levels in the field of Kerr-Newman black hole is analysed. It is shown that bosonic instability may be caused exclusively by the rotation of the black hole. Particulary, the Reissner-Nordstrom configuration is stable. In the case of rotating and charged black hole the bosonic instability may cause an increase of charge of the black hole

Measuring the spins of accreting black holes

International Nuclear Information System (INIS)

McClintock, Jeffrey E; Narayan, Ramesh; Gou, Lijun; Kulkarni, Akshay; Penna, Robert F; Steiner, James F; Davis, Shane W; Orosz, Jerome A; Remillard, Ronald A

2011-01-01

A typical galaxy is thought to contain tens of millions of stellar-mass black holes, the collapsed remnants of once massive stars, and a single nuclear supermassive black hole. Both classes of black holes accrete gas from their environments. The accreting gas forms a flattened orbiting structure known as an accretion disk. During the past several years, it has become possible to obtain measurements of the spins of the two classes of black holes by modeling the x-ray emission from their accretion disks. Two methods are employed, both of which depend upon identifying the inner radius of the accretion disk with the innermost stable circular orbit, whose radius depends only on the mass and spin of the black hole. In the Fe Kα method, which applies to both classes of black holes, one models the profile of the relativistically broadened iron line with a special focus on the gravitationally redshifted red wing of the line. In the continuum-fitting (CF) method, which has so far only been applied to stellar-mass black holes, one models the thermal x-ray continuum spectrum of the accretion disk. We discuss both methods, with a strong emphasis on the CF method and its application to stellar-mass black holes. Spin results for eight stellar-mass black holes are summarized. These data are used to argue that the high spins of at least some of these black holes are natal, and that the presence or absence of relativistic jets in accreting black holes is not entirely determined by the spin of the black hole.

Improved magnetic-field homogeneity of NMR HTS bulk magnet using a new stacking structure and insertion of an HTS film cylinder into a bulk bore

International Nuclear Information System (INIS)

Itoh, Yoshitaka; Yanagi, Yousuke; Nakamura, Takashi

2017-01-01

A new type of superconducting bulk magnet for compact nuclear magnetic resonance (NMR) devices with high magnetic-field homogeneity has been developed by inserting an HTS film cylinder into a bulk superconductor bore. Annular 60 mmϕ Eu-Ba-Cu-O bulk superconductors with a larger inner diameter (ID) of 36 mm were sandwiched between bulk superconductors with a smaller ID of 28 mm, and the total height of the bulk superconductor set was made to be 120 mm. The inner height of central wide bore space was optimized by magnetic-field simulation so that the influence of the bulk superconductor's paramagnetic moment on applied field homogeneity was minimized during the magnetization process. An HTS film cylinder, in which Gd-Ba-Cu-O tapes were wound helically in three layers around a copper cylinder, was inserted into the bulk bore in order to compensate for the inhomogeneous field trapped by the bulk superconductor. The superconducting bulk magnet composed of the above bulk superconductor set and the film cylinder were cooled by a GM pulse tube refrigerator and magnetized at 4.747 T using the field cooling (FC) method and a conventional superconducting coil magnet adjusted to below 0.5 ppm in magnetic-field homogeneity. The NMR measurement was conducted for an H_2O sample with a diameter of 6.9 mm and a length of 10 mm by setting the sample in the center of the 20 mm ID room-temperature bore of the bulk magnet. The magnetic-field homogeneity derived from the full width at half maximum (FWHM) of the "1H spectrum of H_2O was 0.45 ppm. We confirmed that the HTS film inner cylinder was effective in maintaining the homogeneity of the magnetic field applied in the magnetization process, and as a result, a magnetic field with a homogeneity of less than 1 ppm can be generated in the bore of the bulk magnet without using shim coils. (author)

Black holes at neutrino telescopes

International Nuclear Information System (INIS)

Kowalski, M.; Ringwald, A.; Tu, H.

2002-01-01

In scenarios with extra dimensions and TeV-scale quantum gravity, black holes are expected to be produced in the collision of light particles at center-of-mass energies above the fundamental Planck scale with small impact parameters. Black hole production and evaporation may thus be studied in detail at the large hadron collider (LHC). But even before the LHC starts operating, neutrino telescopes such as AMANDA/IceCube, ANTARES, Baikal, and RICE have an opportunity to search for black hole signatures. Black hole production in the scattering of ultrahigh energy cosmic neutrinos on nucleons in the ice or water may initiate cascades and through-going muons with distinct characteristics above the Standard Model rate. In this Letter, we investigate the sensitivity of neutrino telescopes to black hole production and compare it to the one expected at the Pierre Auger Observatory, an air shower array currently under construction, and at the LHC. We find that, already with the currently available data, AMANDA and RICE should be able to place sensible constraints in black hole production parameter space, which are competitive with the present ones from the air shower facilities Fly's Eye and AGASA. In the optimistic case that a ultrahigh energy cosmic neutrino flux significantly higher than the one expected from cosmic ray interactions with the cosmic microwave background radiation is realized in nature, one even has discovery potential for black holes at neutrino telescopes beyond the reach of LHC. (orig.)

Formation and Coalescence of Electron Solitary Holes

DEFF Research Database (Denmark)

Saeki, K.; Michelsen, Poul; Pécseli, H. L.

1979-01-01

Electron solitary holes were observed in a magnetized collisionless plasma. These holes were identified as Bernstein-Green-Kruskal equilibria, thus being purely kinetic phenomena. The electron hole does not damp even though its velocity is close to the electron thermal velocity. Two holes attract...

Notes on Phase Transition of Nonsingular Black Hole

International Nuclear Information System (INIS)

Ma Meng-Sen; Zhao Ren

2015-01-01

On the belief that a black hole is a thermodynamic system, we study the phase transition of nonsingular black holes. If the black hole entropy takes the form of the Bekenstein—Hawking area law, the black hole mass M is no longer the internal energy of the black hole thermodynamic system. Using the thermodynamic quantities, we calculate the heat capacity, thermodynamic curvature and free energy. It is shown that there will be a larger black hole/smaller black hole phase transition for the nonsingular black hole. At the critical point, the second-order phase transition appears. (paper)

Sizes of Black Holes Throughout the Universe

Science.gov (United States)

Kohler, Susanna

2018-05-01

What is the distribution of sizes of black holes in our universe? Can black holes of any mass exist, or are there gaps in their possible sizes? The shape of this black-hole mass function has been debated for decades and the dawn of gravitational-wave astronomy has only spurred further questions.Mind the GapsThe starting point for the black-hole mass function lies in the initial mass function (IMF) for stellar black holes the beginning size distribution of black holes after they are born from stars. Instead of allowing for the formation of stellar black holes of any mass, theoretical models propose two gaps in the black-hole IMF:An upper mass gap at 50130 solar masses, due to the fact that stellar progenitors of black holes in this mass range are destroyed by pair-instability supernovae.A lower mass gap below 5 solar masses, which is argued to arise naturally from the mechanics of supernova explosions.Missing black-hole (BH) formation channels due to the existence of the lower gap (LG) and the upper gap (UG) in the initial mass function. a) The number of BHs at all scales are lowered because no BH can merge with BHs in the LG to form a larger BH. b) The missing channel responsible for the break at 10 solar masses, resulting from the LG. c) The missing channel responsible for the break at 60 solar masses, due to the interaction between the LG and the UG. [Christian et al. 2018]We can estimate the IMF for black holes by scaling a typical IMF for stars and then adding in these theorized gaps. But is this initial distribution of black-hole masses the same as the distribution that we observe in the universe today?The Influence of MergersBased on recent events, the answer appears to be no! Since the first detections of gravitational waves in September 2015, we now know that black holes can merge to form bigger black holes. An initial distribution of black-hole masses must therefore evolve over time, as mergers cause the depletion of low-mass black holes and an increase in

Lectures on Black Hole Quantum Mechanics

Science.gov (United States)

Wilczek, Frank

The lectures that follow were originally given in 1992, and written up only slightly later. Since then there have been dramatic developments in the quantum theory of black holes, especially in the context of string theory. None of these are reflected here. The concept of quantum hair, which is discussed at length in the lectures, is certainly of permanent interest, and I continue to believe that in some generalized form it will prove central to the whole question of how information is stored in black holes. The discussion of scattering and emission modes from various classes of black holes could be substantially simplified using modern techniques, and from currently popular perspectives the choice of examples might look eccentric. On the other hand fashions have changed rapidly in the field, and the big questions as stated and addressed here, especially as formulated for "real" black holes (nonextremal, in four-dimensional, asymptotically flat space-time, with supersymmetry broken), remain pertinent even as the tools to address them may evolve. The four lectures I gave at the school were based on two lengthy papers that have now been published, "Black Holes as Elementary Particles," Nuclear Physics B380, 447 (1992) and "Quantum Hair on Black Holes," Nuclear Physics B378, 175 (1992). The unifying theme of this work is to help make plausible the possibility that black holes, although they are certainly unusual and extreme states of matter, may be susceptible to a description using concepts that are not fundamentally different from those we use in describing other sorts of quantum-mechanical matter. In the first two lectures I discussed dilaton black holes. The fact that apparently innocuous changes in the "matter" action can drastically change the properties of a black hole is already very significant: it indicates that the physical properties of small black holes cannot be discussed reliably in the abstract, but must be considered with due regard to the rest of

Black-Hole Mass Measurements

DEFF Research Database (Denmark)

Vestergaard, Marianne

2004-01-01

The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized.......The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized....

Accretion, primordial black holes and standard cosmology

Indian Academy of Sciences (India)

Primordial black holes evaporate due to Hawking radiation. We find that the evaporation times of primordial black holes increase when accretion of radiation is included. Thus, depending on accretion efficiency, more primordial black holes are existing today, which strengthens the conjecture that the primordial black holes ...

Black holes: a slanted overview

International Nuclear Information System (INIS)

Vishveshwara, C.V.

1988-01-01

The black hole saga spanning some seventy years may be broadly divided into four phases, namely, (a) the dark ages when little was known about black holes even though they had come into existence quite early through the Schwarzschild solution, (b) the age of enlightenment bringing in deep and prolific discoveries, (c) the age of fantasy that cast black holes in all sorts of extraordinary roles, and (d) the golden age of relativistic astrophysics - to some extent similar to Dirac's characterisation of the development of quantum theory - in which black holes have been extensively used to elucidate a number of astrophysical phenomena. It is impossible to give here even the briefest outline of the major developments in this vast area. We shall only attempt to present a few aspects of black hole physics which have been actively pursued in the recent past. Some details are given in the case of those topics that have not found their way into text books or review articles. (author)

Cost-Effectiveness Comparison of Imaging-Guided Prostate Biopsy Techniques: Systematic Transrectal Ultrasound, Direct In-Bore MRI, and Image Fusion

NARCIS (Netherlands)

Venderink, W.; Govers, T.M.; Rooij, M. de; Futterer, J.J.; Sedelaar, J.P.M.

2017-01-01

OBJECTIVE: Three commonly used prostate biopsy approaches are systematic transrectal ultrasound guided, direct in-bore MRI guided, and image fusion guided. The aim of this study was to calculate which strategy is most cost-effective. MATERIALS AND METHODS: A decision tree and Markov model were

Do stringy corrections stabilize colored black holes?

International Nuclear Information System (INIS)

Kanti, P.; Winstanley, E.

2000-01-01

We consider hairy black hole solutions of Einstein-Yang-Mills-dilaton theory, coupled to a Gauss-Bonnet curvature term, and we study their stability under small, spacetime-dependent perturbations. We demonstrate that stringy corrections do not remove the sphaleronic instabilities of colored black holes with the number of unstable modes being equal to the number of nodes of the background gauge function. In the gravitational sector and in the limit of an infinitely large horizon, colored black holes are also found to be unstable. Similar behavior is exhibited by magnetically charged black holes while the bulk of neutral black holes are proved to be stable under small, gauge-dependent perturbations. Finally, electrically charged black holes are found to be characterized only by the existence of a gravitational sector of perturbations. As in the case of neutral black holes, we demonstrate that for the bulk of electrically charged black holes no unstable modes arise in this sector. (c) 2000 The American Physical Society

Mass inflation in the loop black hole

International Nuclear Information System (INIS)

Brown, Eric G.; Mann, Robert; Modesto, Leonardo

2011-01-01

In classical general relativity the Cauchy horizon within a two-horizon black hole is unstable via a phenomenon known as mass inflation, in which the mass parameter (and the spacetime curvature) of the black hole diverges at the Cauchy horizon. Here we study this effect for loop black holes - quantum gravitationally corrected black holes from loop quantum gravity - whose construction alleviates the r=0 singularity present in their classical counterparts. We use a simplified model of mass inflation, which makes use of the generalized Dray-'t Hooft relation, to conclude that the Cauchy horizon of loop black holes indeed results in a curvature singularity similar to that found in classical black holes. The Dray-'t Hooft relation is of particular utility in the loop black hole because it does not directly rely upon Einstein's field equations. We elucidate some of the interesting and counterintuitive properties of the loop black hole, and corroborate our results using an alternate model of mass inflation due to Ori.

Entropy of black holes with multiple horizons

Directory of Open Access Journals (Sweden)

Yun He

2018-05-01

Full Text Available We examine the entropy of black holes in de Sitter space and black holes surrounded by quintessence. These black holes have multiple horizons, including at least the black hole event horizon and a horizon outside it (cosmological horizon for de Sitter black holes and “quintessence horizon” for the black holes surrounded by quintessence. Based on the consideration that the two horizons are not independent each other, we conjecture that the total entropy of these black holes should not be simply the sum of entropies of the two horizons, but should have an extra term coming from the correlations between the two horizons. Different from our previous works, in this paper we consider the cosmological constant as the variable and employ an effective method to derive the explicit form of the entropy. We also try to discuss the thermodynamic stabilities of these black holes according to the entropy and the effective temperature.

Electromagnetic ``black holes'' in hyperbolic metamaterials

Science.gov (United States)

Smolyaninov, Igor

2013-03-01

We demonstrate that spatial variations of the dielectric tensor components in a hyperbolic metamaterial may lead to formation of electromagnetic ``black holes'' inside this metamaterial. Similar to real black holes, horizon area of the electromagnetic ``black holes'' is quantized in units of the effective ``Planck scale'' squared. Potential experimental realizations of such electromagnetic ``black holes'' will be considered. For example, this situation may be realized in a hyperbolic metamaterial in which the dielectric component exhibits critical opalescence.

Features of the electric discharge logging system; Hoden hoshiki jiban tansa system no tokucho

Energy Technology Data Exchange (ETDEWEB)

Kudo, K; Yasuda, N [Tokyo Electric Power Co. Inc., Tokyo (Japan); Kuniyasu, T; Kanda, K; Tanaka, T

1997-10-22

Logging system has been developed, which performs discharge in the water in a bore hole relatively small in diameter. The part of this system to operate in the hole consists of an oscillator that triggers off discharge in the water and an oscillation receiving set that utilizes electrostriction proper to ceramics. The groundborne part of the system is comprised of a probe lift control and logging control. The logging process is carried out by causing discharge in the water in a bore hole filled with water. The energy generated by the oscillator is far greater than that produced in the sonic logging or suspension type logging method, and the wave generated and propagated in the hole is received by the receiving set in the same hole. The result indicates that the P-wave velocity in a hard rockbed is rather high and that values obtained on the spot by this system is quite similar to those obtained from the core sample from the hole. In the case of a rock bed abundant in cracks, thanks to the high S/N ratio such a bed presents and the merits of digital recording, investigations can be minutely conducted. The merit of this system is found in that it can damp the amplitude in dealing with the data collected on the spot. 3 refs., 7 figs.

Black hole Berry phase

NARCIS (Netherlands)

de Boer, J.; Papadodimas, K.; Verlinde, E.

2009-01-01

Supersymmetric black holes are characterized by a large number of degenerate ground states. We argue that these black holes, like other quantum mechanical systems with such a degeneracy, are subject to a phenomenon which is called the geometric or Berry’s phase: under adiabatic variations of the

Black hole accretion: the quasar powerhouse

International Nuclear Information System (INIS)

Anon.

1983-01-01

A program is described which calculates the effects of material falling into the curved space-time surrounding a rotation black hole. The authors have developed a two-dimensional, general-relativistic hydrodynamics code to simulate fluid flow in the gravitational field of a rotating black hole. Such calculations represent models that have been proposed for the energy sources of both quasars and jets from radiogalaxies. In each case, the black hole that powers the quasar or jet would have a mass of about 100 million times the mass of the sun. The black hole would be located in the center of a galaxy whose total mass is 1000 time greater than the black hole mass. (SC)

Charged black holes with scalar hair

Energy Technology Data Exchange (ETDEWEB)

Fan, Zhong-Ying; Lü, H. [Center for Advanced Quantum Studies, Department of Physics,Beijing Normal University, Beijing 100875 (China)

2015-09-10

We consider a class of Einstein-Maxwell-Dilaton theories, in which the dilaton coupling to the Maxwell field is not the usual single exponential function, but one with a stationary point. The theories admit two charged black holes: one is the Reissner-Nordstrøm (RN) black hole and the other has a varying dilaton. For a given charge, the new black hole in the extremal limit has the same AdS{sub 2}×Sphere near-horizon geometry as the RN black hole, but it carries larger mass. We then introduce some scalar potentials and obtain exact charged AdS black holes. We also generalize the results to black p-branes with scalar hair.

Black hole thermodynamics with conical defects

Energy Technology Data Exchange (ETDEWEB)

Appels, Michael [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Gregory, Ruth [Centre for Particle Theory, Durham University,South Road, Durham, DH1 3LE (United Kingdom); Perimeter Institute,31 Caroline Street North, Waterloo, ON, N2L 2Y5 (Canada); Kubiznák, David [Perimeter Institute,31 Caroline Street North, Waterloo, ON, N2L 2Y5 (Canada)

2017-05-22

Recently we have shown https://www.doi.org/10.1103/PhysRevLett.117.131303 how to formulate a thermodynamic first law for a single (charged) accelerated black hole in AdS space by fixing the conical deficit angles present in the spacetime. Here we show how to generalise this result, formulating thermodynamics for black holes with varying conical deficits. We derive a new potential for the varying tension defects: the thermodynamic length, both for accelerating and static black holes. We discuss possible physical processes in which the tension of a string ending on a black hole might vary, and also map out the thermodynamic phase space of accelerating black holes and explore their critical phenomena.

Black hole evaporation: a paradigm

International Nuclear Information System (INIS)

Ashtekar, Abhay; Bojowald, Martin

2005-01-01

A paradigm describing black hole evaporation in non-perturbative quantum gravity is developed by combining two sets of detailed results: (i) resolution of the Schwarzschild singularity using quantum geometry methods and (ii) time evolution of black holes in the trapping and dynamical horizon frameworks. Quantum geometry effects introduce a major modification in the traditional spacetime diagram of black hole evaporation, providing a possible mechanism for recovery of information that is classically lost in the process of black hole formation. The paradigm is developed directly in the Lorentzian regime and necessary conditions for its viability are discussed. If these conditions are met, much of the tension between expectations based on spacetime geometry and structure of quantum theory would be resolved

Do Hypervolumes Have Holes?

Science.gov (United States)

Blonder, Benjamin

2016-04-01

Hypervolumes are used widely to conceptualize niches and trait distributions for both species and communities. Some hypervolumes are expected to be convex, with boundaries defined by only upper and lower limits (e.g., fundamental niches), while others are expected to be maximal, with boundaries defined by the limits of available space (e.g., potential niches). However, observed hypervolumes (e.g., realized niches) could also have holes, defined as unoccupied hyperspace representing deviations from these expectations that may indicate unconsidered ecological or evolutionary processes. Detecting holes in more than two dimensions has to date not been possible. I develop a mathematical approach, implemented in the hypervolume R package, to infer holes in large and high-dimensional data sets. As a demonstration analysis, I assess evidence for vacant niches in a Galapagos finch community on Isabela Island. These mathematical concepts and software tools for detecting holes provide approaches for addressing contemporary research questions across ecology and evolutionary biology.

When Black Holes Collide

Science.gov (United States)

Baker, John

2010-01-01

Among the fascinating phenomena predicted by General Relativity, Einstein's theory of gravity, black holes and gravitational waves, are particularly important in astronomy. Though once viewed as a mathematical oddity, black holes are now recognized as the central engines of many of astronomy's most energetic cataclysms. Gravitational waves, though weakly interacting with ordinary matter, may be observed with new gravitational wave telescopes, opening a new window to the universe. These observations promise a direct view of the strong gravitational dynamics involving dense, often dark objects, such as black holes. The most powerful of these events may be merger of two colliding black holes. Though dark, these mergers may briefly release more energy that all the stars in the visible universe, in gravitational waves. General relativity makes precise predictions for the gravitational-wave signatures of these events, predictions which we can now calculate with the aid of supercomputer simulations. These results provide a foundation for interpreting expect observations in the emerging field of gravitational wave astronomy.

In-bore transrectal MRI-guided prostate biopsies: Are there risk factors for complications?

Energy Technology Data Exchange (ETDEWEB)

Meier-Schroers, Michael, E-mail: michael.meier@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Homsi, Rami, E-mail: rami.homsi@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Kukuk, Guido, E-mail: guido.kukuk@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Wolter, Karsten, E-mail: karsten.wolter@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Decker, Georges, E-mail: georges.decker@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Fischer, Stefan, E-mail: stefan.fischer@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Marx, Christian, E-mail: christian.marx@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Schmeel, Frederic Carsten, E-mail: carsten.schmeel@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Block, Wolfgang, E-mail: wolfgang.block@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Sprinkart, Alois Martin, E-mail: sprinkart@uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Traeber, Frank, E-mail: frank.traeber@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Schild, Hans Heinz, E-mail: hans.schild@ukb.uni-bonn.de [Department of Radiology, University of Bonn, Sigmund-Freud-Str 25, 53127 Bonn (Germany); Willinek, Winfried, E-mail: w.willinek@bk-trier.de [Department of Radiology, Neuroradiology, Sonography and Nuclear Medicine, Hospital of the Barmherzige Brüder Trier, Nordallee 1, 54292 Trier (Germany)

2016-12-15

Purpose: To systematically analyze risk factors for complications of in-bore transrectal MRI-guided prostate biopsies (MRGB). Materials and methods: 90 patients, who were scheduled for MRGB were included for this study. Exclusion criteria were coagulation disorders, therapy with anticoagulant drugs, and acute infections of the urinary and the lower gastrointestinal tract. Directly after, one week and one year after the biopsy, we assessed biopsy related complications (e.g. hemorrhages or signs of prostatitis). Differences between patients with and without complications were analyzed regarding possible risk factors: age, prostate volume, number of taken samples, biopsy duration, biopsy of more than one lesion, diabetes, arterial hypertension, hemorrhoids, benign prostate hyperplasia, carcinoma or prostatitis (according to histopathological analysis), and lesion localization. Complications were classified according to the Clavien-Dindo classification. Results: We observed 15 grade I complications in 90 biopsies (16.7%) with slight hematuria in 9 cases (10%), minor vasovagal reactions in 4 cases (4.4%), and urinary retention and positioning-related facial dysesthesia in 1 case each (1.1%). One patient showed acute prostatitis requiring antibiotics as the only grade II complication (1.1%). There were no adverse events that occurred later than one week. Complications grade III or higher such as pelvic abscesses, urosepsis or severe hemorrhages were not seen. There were no significant associations between the assessed risk factors and biopsy-related complications. Conclusion: In-bore transrectal MRI-guided prostate biopsies can be considered safe procedures in the diagnosis of prostate cancer with very low complication rates. There seem to be no risk factors for complications.

In-bore transrectal MRI-guided prostate biopsies: Are there risk factors for complications?

International Nuclear Information System (INIS)

Meier-Schroers, Michael; Homsi, Rami; Kukuk, Guido; Wolter, Karsten; Decker, Georges; Fischer, Stefan; Marx, Christian; Schmeel, Frederic Carsten; Block, Wolfgang; Sprinkart, Alois Martin; Traeber, Frank; Schild, Hans Heinz; Willinek, Winfried

2016-01-01

Purpose: To systematically analyze risk factors for complications of in-bore transrectal MRI-guided prostate biopsies (MRGB). Materials and methods: 90 patients, who were scheduled for MRGB were included for this study. Exclusion criteria were coagulation disorders, therapy with anticoagulant drugs, and acute infections of the urinary and the lower gastrointestinal tract. Directly after, one week and one year after the biopsy, we assessed biopsy related complications (e.g. hemorrhages or signs of prostatitis). Differences between patients with and without complications were analyzed regarding possible risk factors: age, prostate volume, number of taken samples, biopsy duration, biopsy of more than one lesion, diabetes, arterial hypertension, hemorrhoids, benign prostate hyperplasia, carcinoma or prostatitis (according to histopathological analysis), and lesion localization. Complications were classified according to the Clavien-Dindo classification. Results: We observed 15 grade I complications in 90 biopsies (16.7%) with slight hematuria in 9 cases (10%), minor vasovagal reactions in 4 cases (4.4%), and urinary retention and positioning-related facial dysesthesia in 1 case each (1.1%). One patient showed acute prostatitis requiring antibiotics as the only grade II complication (1.1%). There were no adverse events that occurred later than one week. Complications grade III or higher such as pelvic abscesses, urosepsis or severe hemorrhages were not seen. There were no significant associations between the assessed risk factors and biopsy-related complications. Conclusion: In-bore transrectal MRI-guided prostate biopsies can be considered safe procedures in the diagnosis of prostate cancer with very low complication rates. There seem to be no risk factors for complications.

Does black-hole entropy make sense

International Nuclear Information System (INIS)

Wilkins, D.

1979-01-01

Bekenstein and Hawking saved the second law of thermodynamics near a black hole by assigning to the hole an entropy Ssub(h) proportional to the area of its event horizon. It is tempting to assume that Ssub(h) possesses all the features commonly associated with the physical entropy. Kundt has shown, however, that Ssub(h) violates several reasonable physical expectations. This criticism is reviewed, augmenting it as follows: (a) Ssub(h) is a badly behaved state function requiring knowledge of the hole's future history; and (b) close analogs of event horizons in other space-times do not possess an 'entropy'. These questions are also discussed: (c) Is Ssub(h) suitable for all regions of a black-hole space-time. And (b) should Ssub(h) be attributed to the exterior of a white hole. One can retain Ssub(h) for the interior (respectively, exterior) of a black (respectively, white) hole, but is rejected as contrary to the information-theoretic derivation of horizon entropy given by Berkenstein. The total entropy defined by Kundt (all ordinary entropy on space-section cutting through the hole, no horizon term) and that of Bekenstein-Hawking (ordinary entropy outside horizon plus horizon term) appear to be complementary concepts with separate domains of validity. In the most natural choice, an observer inside a black hole will use Kundt's entropy, and one remaining outside that of Bekenstein-Hawking. (author)

Stationary black holes as holographs

Energy Technology Data Exchange (ETDEWEB)

Racz, Istvan [Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-01 (Japan); MTA KFKI, Reszecske- es Magfizikai Kutatointezet, H-1121 Budapest, Konkoly Thege Miklos ut 29-33 (Hungary)

2007-11-21

Smooth spacetimes possessing a (global) one-parameter group of isometries and an associated Killing horizon in Einstein's theory of gravity are investigated. No assumption concerning the asymptotic structure is made; thereby, the selected spacetimes may be considered as generic distorted stationary black holes. First, spacetimes of arbitrary dimension, n {>=} 3, with matter satisfying the dominant energy condition and allowing a non-zero cosmological constant are investigated. In this part, complete characterization of the topology of the event horizon of 'distorted' black holes is given. It is shown that the topology of the event horizon of 'distorted' black holes is allowed to possess a much larger variety than that of the isolated black hole configurations. In the second part, four-dimensional (non-degenerate) electrovac distorted black hole spacetimes are considered. It is shown that the spacetime geometry and the electromagnetic field are uniquely determined in the black hole region once the geometry of the bifurcation surface and one of the electromagnetic potentials are specified there. Conditions guaranteeing the same type of determinacy, in a neighbourhood of the event horizon, on the domain of outer communication side are also investigated. In particular, they are shown to be satisfied in the analytic case.

Time dependent black holes and scalar hair

International Nuclear Information System (INIS)

Chadburn, Sarah; Gregory, Ruth

2014-01-01

We show how to correctly account for scalar accretion onto black holes in scalar field models of dark energy by a consistent expansion in terms of a slow roll parameter. At leading order, we find an analytic solution for the scalar field within our Hubble volume, which is regular on both black hole and cosmological event horizons, and compute the back reaction of the scalar on the black hole, calculating the resulting expansion of the black hole. Our results are independent of the relative size of black hole and cosmological event horizons. We comment on the implications for more general black hole accretion, and the no hair theorems. (paper)

Quantum Black Holes As Elementary Particles

OpenAIRE

Ha, Yuan K.

2008-01-01

Are black holes elementary particles? Are they fermions or bosons? We investigate the remarkable possibility that quantum black holes are the smallest and heaviest elementary particles. We are able to construct various fundamental quantum black holes: the spin-0, spin 1/2, spin-1, and the Planck-charge cases, using the results in general relativity. Quantum black holes in the neighborhood of the Galaxy could resolve the paradox posed by the Greisen-Zatsepin-Kuzmin limit on the energy of cosmi...

Internal limiting membrane flap transposition for surgical repair of macular holes in primary surgery and in persistent macular holes.

Science.gov (United States)

Leisser, Christoph; Hirnschall, Nino; Döller, Birgit; Varsits, Ralph; Ullrich, Marlies; Kefer, Katharina; Findl, Oliver

2018-03-01

Classical or temporal internal limiting membrane (ILM) flap transposition with air or gas tamponade are current trends with the potential to improve surgical results, especially in cases with large macular holes. A prospective case series included patients with idiopathic macular holes or persistent macular holes after 23-G pars plana vitrectomy (PPV) and ILM peeling with gas tamponade. In all patients, 23-G PPV and ILM peeling with ILM flap transposition with gas tamponade and postoperative face-down position was performed. In 7 of 9 eyes, temporal ILM flap transposition combined with pedicle ILM flap could be successfully performed and macular holes were closed in all eyes after surgery. The remaining 2 eyes were converted to pedicle ILM flap transposition with macular hole closure after surgery. Three eyes were scheduled as pedicle ILM flap transposition due to previous ILM peeling. In 2 of these eyes, the macular hole could be closed with pedicle ILM flap transposition. In 3 eyes, free ILM flap transposition was performed and in 2 of these eyes macular hole could be closed after surgery, whereas in 1 eye a second surgery, performed as pedicle ILM flap transposition, was performed and led to successful macular hole closure. Use of ILM flaps in surgical repair of macular hole surgery is a new option of treatment with excellent results independent of the diameter of macular holes. For patients with persistent macular holes, pedicle ILM flap transposition or free ILM flap transposition are surgical options.

NASA's Chandra Finds Black Holes Are "Green"

Science.gov (United States)

2006-04-01

Black holes are the most fuel efficient engines in the Universe, according to a new study using NASA's Chandra X-ray Observatory. By making the first direct estimate of how efficient or "green" black holes are, this work gives insight into how black holes generate energy and affect their environment. The new Chandra finding shows that most of the energy released by matter falling toward a supermassive black hole is in the form of high-energy jets traveling at near the speed of light away from the black hole. This is an important step in understanding how such jets can be launched from magnetized disks of gas near the event horizon of a black hole. Illustration of Fuel for a Black Hole Engine Illustration of Fuel for a Black Hole Engine "Just as with cars, it's critical to know the fuel efficiency of black holes," said lead author Steve Allen of the Kavli Institute for Particle Astrophysics and Cosmology at Stanford University, and the Stanford Linear Accelerator Center. "Without this information, we cannot figure out what is going on under the hood, so to speak, or what the engine can do." Allen and his team used Chandra to study nine supermassive black holes at the centers of elliptical galaxies. These black holes are relatively old and generate much less radiation than quasars, rapidly growing supermassive black holes seen in the early Universe. The surprise came when the Chandra results showed that these "quiet" black holes are all producing much more energy in jets of high-energy particles than in visible light or X-rays. These jets create huge bubbles, or cavities, in the hot gas in the galaxies. Animation of Black Hole in Elliptical Galaxy Animation of Black Hole in Elliptical Galaxy The efficiency of the black hole energy-production was calculated in two steps: first Chandra images of the inner regions of the galaxies were used to estimate how much fuel is available for the black hole; then Chandra images were used to estimate the power required to produce

Charged spinning black holes as particle accelerators

International Nuclear Information System (INIS)

Wei Shaowen; Liu Yuxiao; Guo Heng; Fu Chune

2010-01-01

It has recently been pointed out that the spinning Kerr black hole with maximal spin could act as a particle collider with arbitrarily high center-of-mass energy. In this paper, we will extend the result to the charged spinning black hole, the Kerr-Newman black hole. The center-of-mass energy of collision for two uncharged particles falling freely from rest at infinity depends not only on the spin a but also on the charge Q of the black hole. We find that an unlimited center-of-mass energy can be approached with the conditions: (1) the collision takes place at the horizon of an extremal black hole; (2) one of the colliding particles has critical angular momentum; (3) the spin a of the extremal black hole satisfies (1/√(3))≤(a/M)≤1, where M is the mass of the Kerr-Newman black hole. The third condition implies that to obtain an arbitrarily high energy, the extremal Kerr-Newman black hole must have a large value of spin, which is a significant difference between the Kerr and Kerr-Newman black holes. Furthermore, we also show that, for a near-extremal black hole, there always exists a finite upper bound for center-of-mass energy, which decreases with the increase of the charge Q.

Thermodynamics of the Schwarzschild-de Sitter black hole: Thermal stability of the Nariai black hole

International Nuclear Information System (INIS)

Myung, Yun Soo

2008-01-01

We study the thermodynamics of the Schwarzschild-de Sitter black hole in five dimensions by introducing two temperatures based on the standard and Bousso-Hawking normalizations. We use the first-law of thermodynamics to derive thermodynamic quantities. The two temperatures indicate that the Nariai black hole is thermodynamically unstable. However, it seems that black hole thermodynamics favors the standard normalization and does not favor the Bousso-Hawking normalization

Measurements of cutter forces and cutter temperature of boring machine in Aespoe Hard Rock Laboratory

Energy Technology Data Exchange (ETDEWEB)

Zhang, Z.X.; Kou, S.Q.; Lindqvist, P.-A. [Luleaa Univ. of Technology (Sweden)

2001-04-01

This report presents both the testing methods used and the testing results obtained for cutter forces and cutter temperature during field boring in Aespoe Hard Rock Laboratory. In order to estimate the strains induced by cutter forces in the cutter shaft and choose proper transducers, first a numerical simulation was performed. The simulation results indicated that the cutter forces should be measurable by ordinary strain gauges. Furthermore, an independent three-direction loading system for laboratory calibration was set up to solve force-coupling problems appearing in field measurements. By means of the established measuring system, which was proved successfully in the laboratory, the normal forces, tangential forces, and side forces of two button cutters in the boring machine were measured in the field. In addition, the temperature in the shaft of the front cutter was measured. After the measurements of the cutter forces and cutter temperature, rock core samples were taken from the bottom and the wall of the testing borehole. Then the samples were cut, polished, and examined by means of the Scanning Electron Microscope (SEM). After that, the lengths of major cracks induced by the cutters in the rock samples were measured, and an approximate relationship between the length of the medium cracks and the relevant cutter forces was obtained. This relationship was compared with the theoretical relationship established before. Finally, according to the measured results, the cracked zones around the borehole were described. The results show that: (1) there are two kinds of cracked zones: one in the borehole wall and the other in the bottom of the borehole. The depth of the cracked zone in the borehole bottom is much larger than that in the borehole wall because the maximum normal force of the front cutter is always much larger than that of the gauge cutter. (2) Each cracked zone includes a densely cracked zone and all the longest medium cracks caused by mechanical

Magnonic black holes

OpenAIRE

Roldán-Molina, A.; Nunez, A.S.; Duine, R. A.

2017-01-01

We show that the interaction between spin-polarized current and magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons - the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the imp...

Familial trends in a population with macular holes.

Science.gov (United States)

Kay, Christine Nichols; Pavan, Peter Reed; Small, Laurie Buccina; Zhang, Tao; Zamba, Gideon K D; Cohen, Steven Myles

2012-04-01

To determine if patients with macular hole report an increased family history of macular hole compared with control patients and compare the report of family history between patients with unilateral and bilateral macular holes. This was a multicenter case-control study. Charts of patients coded with diagnosis of macular hole were reviewed, and the diagnosis of idiopathic full-thickness macular hole was ascertained in 166 patients. The control group comprised 136 patients without macular hole or trauma who presented with senile cataract. Family history was obtained from all patients through a telephone interview. Six of 166 (3.6%) macular hole patients surveyed reported a history of macular hole in a primary relative compared with none of 136 (0.0%) control patients (odds ratio is infinity, with 95% confidence interval 1.295 to infinity); however, this finding may be explained by confounders such as age and number of family members. Two of the 142 (1.4%) patients with unilateral holes versus 4 of the 24 (16.7%) patients with bilateral holes reported a family history (odds ratio is 0.0714, with 95% confidence interval 0.0063 to 0.5537), and this finding remains significant when logistic regression is performed to evaluate variables of age and number of family members as potential confounders. There is an increased report of familial occurrence of macular hole in patients with macular holes compared with control patients; however, logistic regression relates this finding to variables of age and number of family members. Patients with bilateral macular holes are more likely to report a family history of macular hole than patients with unilateral macular holes, and this finding remains significant in the presence of age and number of family members. These findings may suggest a familial component to macular hole.

Charged topological black hole pair creation

International Nuclear Information System (INIS)

Mann, R.B.

1998-01-01

I examine the pair creation of black holes in space-times with a cosmological constant of either sign. I consider cosmological C-metrics and show that the conical singularities in this metric vanish only for three distinct classes of black hole metric, two of which have compact event horizons on each spatial slice. One class is a generalization of the Reissner-Nordstroem (anti-)de Sitter black holes in which the event horizons are the direct product of a null line with a 2-surface with topology of genus g. The other class consists of neutral black holes whose event horizons are the direct product of a null conoid with a circle. In the presence of a domain wall, black hole pairs of all possible types will be pair created for a wide range of mass and charge, including even negative mass black holes. I determine the relevant instantons and Euclidean actions for each case. (orig.)

The membrane paradigm for black holes

International Nuclear Information System (INIS)

Price, R.H.; Thorne, K.S.

1988-01-01

It is now widely accepted that black holes exist and have an astrophysical role, in particular as the likely power source of quasars. To understand this role with ease, the authors and their colleagues have developed a new paradigm for black holes - a new way to picture, think about and describe them. As far as possible it treats black holes as ordinary astrophysical objects, made of real material. A black hole in this description is a spherical or oblate surface made of a thin, electrically conducting membrane. It was the author's quest to understand the Blandford-Znajek process intuitively that led them to create the membrane paradigm. Their strategy was to translate the general-relativistic mathematics of black holes into the same language of three-dimensional space that is used for magnetized plasmas and to create a new set of black-hole diagrams and pictures to go along with the language. 9 figs

Seeding black holes in cosmological simulations

Science.gov (United States)

Taylor, P.; Kobayashi, C.

2014-08-01

We present a new model for the formation of black holes in cosmological simulations, motivated by the first star formation. Black holes form from high density peaks of primordial gas, and grow via both gas accretion and mergers. Massive black holes heat the surrounding material, suppressing star formation at the centres of galaxies, and driving galactic winds. We perform an investigation into the physical effects of the model parameters, and obtain a `best' set of these parameters by comparing the outcome of simulations to observations. With this best set, we successfully reproduce the cosmic star formation rate history, black hole mass-velocity dispersion relation, and the size-velocity dispersion relation of galaxies. The black hole seed mass is ˜103 M⊙, which is orders of magnitude smaller than that which has been used in previous cosmological simulations with active galactic nuclei, but suggests that the origin of the seed black holes is the death of Population III stars.