Energy Technology Data Exchange (ETDEWEB)

The choice of vacuum state for a quantum scalar field propagating in a de Sitter spacetime (massive and arbitrarily coupled to the gravitational field) is discussed. The problem of finite-time initial conditions for the mode functions is analyzed, as well as how these determine the vacuum state of the quantum system. The principle guiding the choice of vacuum state is the following: one wants the vacuum contribution to the energy-momentum tensor to contain all the ultraviolet divergent terms, so that the particle creation terms are finite, and covariantly conserved. There is a suitable set of modes (instantaneous adiabatic basis) in which this splitting of the expectation value of the energy-momentum tensor can be carried out. Numerical results are presented for different finite-time initial conditions (m = 0.6, {zeta} = 1/6). The nature of the particle creation effect is described ...

CERN Document Server

We study the all-optical time-control of the strong coupling between a single cascade three-level quantum emitter and a microcavity. We find that only specific arrival-times of the control pulses succeed in switching-off the Rabi oscillations. Depending on the arrival times of control pulses, a variety of exotic non-adiabatic cavity quantum electrodynamics effects can be observed. We show that only control pulses with specific arrival times are able to suddenly switch-off and -on first-order coherence of cavity photons, without affecting their strong coupling population dynamics. Such behavior may be understood as a manifestation of quantum complementarity.

Science.gov (United States)

Not Available

Energy Technology Data Exchange (ETDEWEB)

A calorimetric sensor with several novel design features has been developed. These sensors will provide an accurate sampling of thermal power density and energy deposition from proton beams incident on target components of accelerator-based systems, such as the Accelerator Production of Tritium Project (APT) and the Spallation Neutron Source (SNS). A small, solid slug (volume = 0.347 cc) of target material is suspended by kevlar fibers and surrounded by an adiabatic enclosure in an insulating vacuum canister of stainless steel construction. The slug is in thermal contact with a low-mass, calibrated, 100-k{Omega} thermistor. Power deposition caused by the passage of radiation through the slug is calculated from the rate of temperature rise of the slug. The authors have chosen slugs composed of Pb, Al, and LiAl.

British Library Electronic Table of Contents (United Kingdom)

Heat transfer through the gas diffusion layer (GDL) is a key process in the design and operation of a PEM fuel cell. The analysis of this process requires determination of the effective thermal conductivity as well as the thermal contact resistance associated with the interface between the GDL and adjacent surfaces/layers. In the present study, a custom-made test bed that allows the separation of effective thermal conductivity and thermal contact resistance in GDLs under vacuum and ambient conditions is described. Measurements under varying compressive loads are performed using Toray carbon paper samples with a porosity of 78% for a range of thicknesses. The measurements are complemented by compact analytical models that achieve good agreement with experimental data. A key finding is that ...

Energy Technology Data Exchange (ETDEWEB)

In the present work temperature dependences of heat capacity of carbosilane dendrimers with butyl terminal groups of the third and the fourth generations as well as of the fifth and the sixth generations have been determined first in the range from 6 to 340K and between 6 and 600K, respectively, by precision adiabatic vacuum and dynamic calorimetry. In the above temperature ranges the physical transformations have been detected and their thermodynamic characteristics have been estimated and analyzed. The experimental data were used to calculate standard thermodynamic functions, namely the heat capacity C{sub p}{sup o}(T), enthalpy H{sup o}(T)-H{sup o}(0), entropy S{sup o}(T)-S{sup o}(0) and Gibbs function G{sup o}(T)-H{sup o}(T), for the range from T->0 to (340-600)K. Linear dependences of changing the corresponding thermodynamic functions of the dendrimers on their molecular weight and the number of butyl groups on an outer sphere have ...

Energy Technology Data Exchange (ETDEWEB)

Apparent molar volumes of aqueous methyldiethanolamine and its salt were determined with platinum vibrating tube densitometers over a range of temperatures from 283K=<T=<576K and at pressures from 0.1MPa to 20MPa. Apparent molar heat capacities were obtained using a Sodev Picker flow microcalorimeter at a pressure of 0.1MPa and within the temperature range of 283K=<T=<328K. Apparent molar adiabatic and isothermal compressibilities at a pressure of 0.1MPa were obtained at temperatures from 283K=<T=<313K with speed of sound measurements. The experimental results were extrapolated to infinite dilution to obtain values for the standard partial molar volumes V{sup o}, heat capacities C{sub p}{sup o}, and isothermal compressibilities {kappa}{sub T}{sup o}. The standard partial molar volumes V{sup o} for the neutral amine and its salt show increasingly positive and negative values, ...

International Nuclear Information System (INIS)

The generation of fusion power from the Fast-Liner Reactor (FLR) concept envisages the implosion of a thin (3-mm) metallic cylinder (0.2-m radius by 0.2-m length) onto a preinjected plasma. This plasma would be heated to thermonuclear temperatures by adiabatic compression, pressure confinement would be provided by the liner inertia, and thermal insulation of the wall-confined plasma would be established by an embedded azimuthal magnetic field. A 2- to 3-mu s burn would follow the approx. 10"4 m/s radial implosion and would result in a thermonuclear yield equal to 10 to 15 times the energy initially invested into the liner kinetic energy. For implosions occurring once every 10 s a gross thermal power of 430 MWt would be generated. The results of a comprehensive systems study of both physics and technology (economics) optima are presented. Despite unresolved problems associated with both the physics and technology of the FLR, a conceptual power ...

Energy Technology Data Exchange (ETDEWEB)

Heat transfer through the gas diffusion layer (GDL) is a key process in the design and operation of a PEM fuel cell. The analysis of this process requires determination of the effective thermal conductivity as well as the thermal contact resistance associated with the interface between the GDL and adjacent surfaces/layers. In the present study, a custom-made test bed that allows the separation of effective thermal conductivity and thermal contact resistance in GDLs under vacuum and ambient conditions is described. Measurements under varying compressive loads are performed using Toray carbon paper samples with a porosity of 78% for a range of thicknesses. The measurements are complemented by compact analytical models that achieve good agreement with experimental data. A key finding is that thermal contact resistance is the dominant component of the total thermal resistance; neglecting this phenomenon may result in significant errors in ...

Energy Technology Data Exchange (ETDEWEB)

We consider the pre-Big-Bang scenario with a massive axion field which starts to dominate energy density when oscillating in an instanton-induced potential and subsequently reheats the universe as it decays into photons, thus creating adiabatic CMB perturbations. We find that the fluctuations in the axion field can give rise to a nearly flat spectrum of adiabatic perturbations with a spectral tilt {delta}n in the range -0.1< or approx. {delta}n < or approx. 1.

Science.gov (United States)

... slenderness ratio. Equations which determine the ultimate compressive strength of a composite were established. Several ...

Energy Technology Data Exchange (ETDEWEB)

The construction of networks consisting of optically interconnected processing units is a promising way to scale up quantum information processing systems. To store quantum information, single trapped atoms are among the most proven candidates. By placing them in high finesse optical resonators, a bidirectional information exchange between the atoms and photons becomes possible with, in principle, unit efficiency. Such an interface between stationary and ying qubits constitutes a possible node of a future quantum network. The results presented in this thesis demonstrate the prospects of a quantum interface consisting of a single atom trapped within the mode of a high-finesse optical cavity. In a two-step process, we distribute entanglement between the stored atom and two subsequently emitted single photons. The long atom trapping times achieved in the system together with the high photon collection efficiency of the cavity make the applied protocol in principle deterministic, allowing ...

International Nuclear Information System (INIS)

Sodium silicate is vacuum impregnated in bauxite waste (red mud) at room temperature to develop ceramics of mechanical properties comparable to the sintered ceramics. For a concentration up to 10% the fracture toughness increases from 0.12 MNm"-"3"/"2 to 0.9 MNm"-"3"/"2, and the compressive strength from 7 MNm"-"2 to 30 MNm"-"2. The mechanical properties do not deteriorate, when soaked in water for an entire week. The viscosity and the concentration of the silicate solution are crucial, both for the success of the fabrication and the economics of the process. Similar successful results have been obtained for bauxite and lime stone, even though the latter has poor weathering properties. With scanning electron microscopy and energy dispersive analysis, an attempt is made to identify the crystals formed in the composite, which are responsible for the strength. The process is an economic alternative to the sintered ceramics in the construction ...

KoreaScience (Korea)

Full Text Available

Science.gov (United States)

... Title : Compressive and Shear Buckling Analysis of Metal Matrix Composite Sandwich Panels Under Different Thermal Environments. ...

Science.gov (United States)

The results of this research centered on the experimental studies of a single superconducting persistent current qubit, the implementation of type-II algorithms using these qubits, and the proposal for adiabatic quantum computing using these qubits. The m...

Energy Technology Data Exchange (ETDEWEB)

It is shown that a simple algorithm which exactly segregates between adiabatic and non-adiabatic electrons in particle-in-cell simulations of drift modes yields excellent conservation properties (e.g. particle number, energy) compared to the conventional df scheme. The removal of the free streaming term in the evolution of the marker weight is shown to be responsible for the improved linear and nonlinear properties of the simulated plasma.

Energy Technology Data Exchange (ETDEWEB)

This paper reports new formulas of adiabatic flame temperature. They are functionally expressed in terms of fuel/air ratio, reaction pressure, and the number of carbon atoms in the individual fuel. Among the fuels presently considered for the formulas are members of paraffin, aromatic and olefin families, acetylene, alcohols, and hydrogen.

Energy Technology Data Exchange (ETDEWEB)

Hamiltonian light-front dynamics of quantum fields may provide a useful approach to systematic nonperturbative approximations to quantum field theories. The authors investigate inequivalent Hilbert-space representations of the light-front field algebra in which the stability group of the light front is implemented by unitary transformations. The Hilbert space representation of states is generated by the operator algebra from the vacuum state. There is a large class of vacuum states besides the Fock vacuum which meets all the invariance requirements. The light-front Hamiltonian must annihilate the vacuum and have a positive spectrum. Relations are exhibited of the Hamiltonian to the nontrivial vacuum structure. 30 refs.

International Nuclear Information System (INIS)

It is shown that vacuum instabilities possibly arising because of tachyons do not contradict any experimental evidence, and therefore that no objection against tachyon existence can be found even on this ground. (Auth.).

Energy Technology Data Exchange (ETDEWEB)

A wood/polymer composite was produced by impregnating Ramin wood with methyl methacrylate monomer and subsequently polymerizing it by gamma irradiation. To assess the improvement in compression strength of the wood caused by the polymer impregnation, a microbuckling compression failure mechanism was used to model the compression failure of the composite. Such a mechanism was found to predict a linear relationship between the compression strength and the percentage polymer impregnation (by weight). Uniaxial compression test results at 45({plus minus}5)% and 90({plus minus}5)% relative humidity levels, after being statistically analysed, showed that such a linear relationship was valid for up to 100% polymer impregnation. (author).

CERN Document Server

Technology progress in DNA sequencing boosts the genomic database growth at faster and faster rate. Compression, accompanied with random access capabilities, is the key to maintain those huge amounts of data. In this paper we present an LZ77-style compression scheme for relative compression of multiple genomes of the same species. While the solution bears similarity to known algorithms, it offers significantly higher compression ratios at compression speed over a order of magnitude greater. One of the new successful ideas is augmenting the reference sequence with phrases from the other sequences, making more LZ-matches available.

British Library Electronic Table of Contents (United Kingdom)

We propose a method for the creation of arbitrary superposition of N atomic states using generalized stimulated Raman adiabatic passage (STIRAP) techniques with laser fields coupling each one of N lower states to a single upper state in a Formula Not Shown -level atomic system. Formula Not Shown dark states that are composed of N lower states span a dark subspace. In the adiabatic limit, the dark and bright subspaces are decoupled, thus the nonadiabatic interaction within this dark subspace dominates the evolution of the system. Different from general methods to create our required coherent superposition state, in a reverse way, here we consider the required state as the starting point of evolution dynamics, and utilize laser fields to drive it into a single lower state step by step. Time ...

Energy Technology Data Exchange (ETDEWEB)

The characteristic rich shifting of the maximum adiabatic flame temperature from the stoichiometric value for mixtures of hydrocarbon and air is demonstrated to be caused by product dissociation and hence reduced amount of heat release. Since the extent of dissociation is greater on the lean side as a result of the stoichiometry of dissociated products, the peaking occurs on the rich side. The specific heat per unit mass of the mixture is shown to increase monotonically with increasing fuel concentration, and as such tends to shift the peak toward the lean side. It is further shown that this is the cause for the lean shifting of the adiabatic flame temperature of oxidizer-enriched mixtures of N{sub m}H{sub n} and F{sub 2} and of NH{sub 3} and O{sub 2}, with various amounts of inert dilution, even though their maximum heat release still peaks on the rich side. (author)

Science.gov (United States)

... Accession Number : ADD421949. Title : Ultimate Compressive Strength and Nonlinear Stress-Strain Curves of Graphite/Epoxy Laminates,. ...

Science.gov (United States)

Ultimate compressive strength and failure modes were studied using 24- ... to 81 % of the average ultimate compressive strength (UCS). Figure 1 (a) is the failure ...

Science.gov (United States)

... Page 26 Ultimate compressive strength versus fly ash/cement limits 41 ... 222 El Ultimate compressive strength versus water/(cement + fly ash) 250 ...

Science.gov (United States)

... The measured elastic modulus was fairly close to the predicted value, but the ultimate compressive strength (UCS) was quite a bit below the MSC ...

Science.gov (United States)

A method of strength analysis of short sheet-stringer panels subjected to compression is presented

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The vacuum system of the XVTS (X-Ray Vacuum Transport System) for the LCLS (Linac Coherent Light Source) XTOD (X-ray Transport, Optics and Diagnostics) system has been analyzed and configured by the Lawrence Livermore National Laboratory's NTED (New Technologies Engineering Division) as requested by the SLAC/LCLS program. The system layout, detailed analyses and selection of the vacuum components for the XTOD tunnel section are presented in this preliminary design report. The vacuum system was analyzed and optimized using a coupled gas load balance model of sub-volumes of the components to be evacuated. Also included are the plans for procurement, mechanical integration, and the cost estimates.

Energy Technology Data Exchange (ETDEWEB)

For sufficiently cool remote gases, the cylindrical stretched flame shows classical ignition-extinction behavior. For remote gas temperatures close to the adiabatic flame temperature, the flame response is qualitatively different, with negative flame speed solutions which may be physically accessible.

CERN Document Server

We consider the adiabatic demagnetization in the rotating reference frame (ADRF) of a system of dipolar coupled nuclear spins $s=1/2$ in the external magnetic field. The demagnetization starts with the offset of the external magnetic field (in frequency units) from the Larmor frequency being several times greater than the local dipolar field. For different subsystem sizes, we have found from numerical simulations the temperatures at which subsystems of a one-dimensional nine-spin chain and a plane nine-spin cluster become entangled. These temperatures are of the order of microkelvins and are almost independent of the subsystem size. There is a weak dependence of the temperature on the space dimension of the system.

Science.gov (United States)

... ULTRASONIC VIBRATION TO PORTLAND CEMENT-WATER PASTE REDUCES THE ULTIMATE COMPRESSIVE STRENGTH OF MORTARS ...

KoreaScience (Korea)

Full Text Available

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Science.gov (United States)

In 1963, Grover and co-workers at the Los Alamos. Scientific. Laboratory ...... and A. P. Watkins. (1986) "The Computation of Compressible ...

Science.gov (United States)

... Accession Number : ADD141533. Title : Yttrium Oxides in Vacuum-Plasma- Sprayed CoNiCrAlY Coatings,. Descriptive Note : Journal Article,. ...

International Nuclear Information System (INIS)

The possibility of surface modification of high-speed steel cutting tool by means of vacuum-plasma treatment including ion nitriding in gas plasma followed by the deposition of wear resistant (Ti, Al)N coatings in metal-gas plasma of a vacuum arc discharge is studied. The regularities of nitrided layer formation and the structure of these layers under various operation conditions of cutting tool are investigated. Optimum conditions of vacuum-plasma treatment providing the best wear resistance of cutting are determined

International Science & Technology Center (ISTC)

Development of Method and Technical Project of the Plant for Thermo-Vacuum Desorption of Tritium Oxide (HTO) from the Environmental Samples

International Nuclear Information System (INIS)

The method of an effective potential is used to investigate the possible types of evolution of vacuum shells in the Friedmann-Schwarzschild world. Such shells are assumed to emerge during phase transitions in the early Universe. The possible global geometries are constructed for the Friedmann-Schwarzschild worlds. Approximate solutions to the equation of motion of a vacuum shell have been found. The conditions under which the end result of the evolution of the vacuum shells under consideration is the formation of black holes and wormholes with baby universes inside have been found. The interior of this world can be a closed, flat, or open Friedmann universe.

Energy Technology Data Exchange (ETDEWEB)

My assignment on the SP-100 Vacuum Vessel Vacuum System Team was to perform a transient pump down analysis for the vacuum vessel that will house the SP-100 reactor during testing. Pump down time was calculated for air and helium. For all cases the proposed vacuum system will be able to pump down the vessel within the required time. The use of a larger rotary piston pump (DUO250) improves the pump down time by 35 minutes and therefore should be considered. The 6-inch duct for the roughing line is optimal, however, because all cases are well below the 24 hour time frame, the 4-inch duct is sufficient. The use of the single turbomolecular pump during pump down is sufficient. A pump down with helium in the vessel and a helium inleakage delays the time to achieve the base pressure marginally and is acceptable.

UK PubMed Central (United Kingdom)

Chest compression-only (CC-only) is now incorporated in the Norwegian protocol for dispatch guided CPR (cardiopulmonary resuscitation) in cardiac arrest of presumed cardiac aetiology.We present...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Longitudinal compression of space-charge dominated beams can be achieved by imposing a head-to-tail velocity tilt on the beam. This tilt has to be carefully tailored, such that it is removed by the longitudinal space-charge repulsion by the time the beam reaches the end of the drift compression section. The transverse focusing lattice should be designed such that all parts of the beam stay approximately matched, while the beam smoothly expands transversely to the larger beam radius needed in the final focus system following drift compression. In this thesis, several drift compression systems were designed within these constraints, based on a given desired pulse shape at the end of drift compression systems were designed within these constraints, based on a given desired pulse shape at the end of drift compression. The occurrence of mismatches due to a rapidly ...

UK PubMed Central (United Kingdom)

Various physico-chemical tissue optical clearing (TOC) methods have been suggested to maximize photon density in tissue. In order to enhance photon density, a compression-controlled low-level...Full Text Available

International Nuclear Information System (INIS)

Vacuum glazing consists of an evacuated space between two sheets of glass. Vacuum glazing has a large effect on energy savings in houses and buildings. Vacuum glazing can achieve higher insulating performance than conventional insulated glazing. Nippon Sheet Glass has successfully developed conventional vacuum glazing. In this study we investigated an advanced form of vacuum glazing. Its thermal insulation ability is equivalent to 100 mm thick glass wool thermal insulation. This vacuum glazing contained a SnO_2:F low emissivity surface. The influence of the residual gas in a vacuum space on heat flow is important to performance. For long-term thermal stability, it is very important to maintain vacuum stability. To understand this better, we studied the behavior of outgassing from the inside glass surfaces exposed to an ...

Science.gov (United States)

... The ultimate compressive strength was measured, and values for Young's modulus were calculated from the linear portion of the test curve. ...

Science.gov (United States)

... hydrostatic pressures up to 700 MPa. The effect of pressure on the ultimate compressive strength is shown. The effect of size on ...

International Nuclear Information System (INIS)

The compressive and torsional buckling behavior of carbon nanotube bundles at room temperature is examined with classical molecular dynamics simulation. The critical compressive load and stiffness of a single carbon nanotube in the bundle are found to be similar to those of individual carbon nanotubes. However, the critical torsional moment and stiffness of a single carbon nanotube in the bundle are found to be higher than those of individual carbon nanotubes. In addition, this study demonstrates that van der Waals interactions between the nanotubes in the bundle significantly affect the critical compressive load of the nanotube bundle.

CERN Document Server

We present a description of nuclear spontaneous fission, and generally of quantum tunneling, in terms of instantons - periodic imaginary-time solutions to time-dependent mean-field equations - that allows for a comparison with more familiar and used generator coordinate (GCM) and adiabatic time-dependent Hartree-Fock (ATDHF) methods. It is shown that the action functional whose value for the instanton is the quasiclassical estimate of the decay exponent fulfils the minimum principle when additional constraints are imposed on trial fission paths. In analogy with mechanics, these are conditions of energy conservation and the velocity-momentum relations. In the adiabatic limit the instanton method reduces to the time-odd ATDHF equation, with collective mass including the time-odd Thouless-Valatin term, while the GCM mass completely ignores velocity-momentum relations. This implies that GCM inertia generally overestimates instanton-related decay ...

Energy Technology Data Exchange (ETDEWEB)

Typical beam lines are comprised of an assembly of vacuum valves and shutters referred to as a ''front end'', optical elements to monochromatize, focus and split the photon beam, and an experimental area where a target sample is placed into the photon beam and data from the interaction is detected and recorded. Windows are used to separate sections of beam lines that are not compatible with storage ring ultra high vacuum. Some experimental beam lines share a common vacuum with storage rings. Sections of beam lines are only allowed to vent up to atmospheric pressure using pure nitrogen gas after a vacuum barrier is established to protect ring vacuum. The front end may only be bled up when there is no current in the machine. This is especially true on the VUV storage ring where for most experiments, windows are not used. For the shorter wavelength, ...

Energy Technology Data Exchange (ETDEWEB)

Equations are derived to calculate the work required for the isentropic compression of a 2-phase fuel-air mixture. Methanol evaporation during compression substantially reduces compression work and improves cycle efficiency and maximum power. Effects of evaporative cooling in the intake manifold are calculated. Energy d. of methanol and gasoline fuel-air charges are compared. The phase equilibrium and evaporation rate are causes of the poor cold-starting performance of methanol.

Energy Technology Data Exchange (ETDEWEB)

The purpose of the invention is to improve adaptability of a compression shield to irregularities of a face. This goal is achieved in that a compressible shield is made in the form of a lattice of elastic transverse plates with grooves, elastic vertical elements installed in the grooves, and an elastic plate which is concave toward the face. The plate is located vertically in the middle of the shield. The compressible shield is attached by hinges to a deflector. Telescopic cross pieces are attached by hinges to the covering section of reinforcement, offering the possibility of longitudinal movement at the point of attachment.

Energy Technology Data Exchange (ETDEWEB)

In this paper, the multisource geoscientific data, such as TM data, NOAA data, the data of Bouguer gravity anomaly and aeromagnetic anomaly, the multisource geophysical processing methods, such as upward continuations, vertical derivative and gradient image, and synthetic image processing method - remote sensing image processing and geophysical image processing under I{sup 2}S600, are used to study the reverse faults or thrusts in the southern margin of Ordos basin, China. On the basis of these results and with geological investigation in the field, the authors have determined three thrust compression systems, named EW thrust compression system, NE thrust compression system and NW thrust compression system. These three systems reveal the regularity of geological structural evolution in the southern margin of Ordos basis and in the north side of Qinling Orogenic Belt.

Energy Technology Data Exchange (ETDEWEB)

The feasibility of using hydrogen as the sole fuel in a direct injection diesel engine was investigated. An air cooled single cylinder Lister ST1 diesel engine was modified to operate as a low-heat-rejection engine for this study. Partially stabilized zirconia ceramic parts were used to shield the combustion space of the engine. Using a compression ratio of 17.9:1 and motoring the test engine at 21000 rpm, a maximum compression temperature of approximately 900 K was achieved. Under these operating conditions, all lubricants tested were found to burn. Lowering the speed to 1450 rpm and the compression ratio to 17.1, lubricant combustion and hot spots were successfully eliminated. The maximum compression temperature, when compression ignition of hydrogen was tried, was in the 800 K range. The corresponding ceramic surface temperature was estimated to reach 600-700 K. Only sporadic ...

Energy Technology Data Exchange (ETDEWEB)

In this paper coating developments for advanced gas turbine engines (diffusion aluminide coatings, overlay coatings, and ceramic thermal barrier coatings) were desorbed, a selection of current metallic coatings was made and their performance as outlined. Finally coating developments for advanced diesel engines with a view to improved turbocharging or to low heat rejection engines (adiabatic diesel concept) were dealt with. (IHOE).

Energy Technology Data Exchange (ETDEWEB)

Angular wave functions are investigated which describe the motion of two electrons in the field of a nucleus at fixed equal distances from electrons to the nucleus. Calculation methods are considered that include matching of power series and expansion in series of Legendre polynomials. Asymptotic properties of solutions at small large distances are determined.

Energy Technology Data Exchange (ETDEWEB)

A solid electrolyte cell comprises an alkali metal anode, e.g. lithium, a halogen-containing organic polymer cathode and a solid elecrolyte between the anode and the cathode. The cathode comprises iodine-containing vacuum-cyclised polyacrylonitrile, and the solid electrolyte is preferably lithium iodide and halogen-free vacuum-cyclised polyacrylonitrile. This patent also discloses the use of isotactic polyacrylonitrile, a method of making a cathode comprising iodine-containing vacuum-cyclised polyacrylonitrile, and novel methods of making the solid elecrolyte cells described.

Energy Technology Data Exchange (ETDEWEB)

Purification parameters of the vacuum distillation process for AM50A and AZ31B magnesium alloy were studied. The vacuum distillation tests were kept at 580 C to 620 C up to 10 h under a vacuum pressure of about 1 Pa. The purification ratio for AM50A magnesium alloy increases with increasing the purification time. The chemical compositions of materials deposited purifying at 580 C for AM50A magnesium alloy almost satisfy the values for pure magnesium specified by JIS standard specification. The chemical compositions of deposited materials at 600 C for AZ31B magnesium alloy satisfy the values specified by the standard specification except for Zn. (orig.)

British Library Electronic Table of Contents (United Kingdom)

Environmental scanning electron microscopy (ESEM) allows the examination of hydrated and dried specimens without a conductive metal coating which could be advantageous in the imaging of biological and medical objects. The aim of this study was to assess the performance and benefits of wet-mode and low vacuum ESEM in comparison to high vacuum scanning electron microscopy (SEM) using the choroid plexus of chicken embryos as a model, an organ of the brain involved in the formation of cerebrospinal fluid in vertebrates. Specimens were fixed with or without heavy metals and examined directly or after critical point drying with or without metal coating. For wet mode ESEM freshly excised specimens without any pre-treatment were also examined. Conventional high vacuum SEM revealed the characterist...

British Library Electronic Table of Contents (United Kingdom)

This paper presents the results of the degree of irreversible changes of dielectric properties of vacuum circuit breakers with CuCr and CuBi contacts before and after short-circuit breaking operations. Tests of dielectric properties were performed on four different types of switching vacuum chamber with RMF electrodes in the form of a spiral disk with slots. The paper describes the configuration of measuring system for determining the dielectric properties of circuit breakers with DC, AC and pulse voltage. It also describes the measuring procedure. The results were analyzed and the experimentally obtained random variable breakdown voltage is found to belong to Weibull distribution in all cases. Based on these results it was found that for the vacuum circuit breakers with CuCr contacts and ...

Energy Technology Data Exchange (ETDEWEB)

The authors solve the instability of perturbative vacuum of Gross-Neveu model. They use a variational method. The analysis is nonperturbative as it uses only equal time commmutator/anticommutator algebra.

Energy Technology Data Exchange (ETDEWEB)

This thesis enters the field of highly compressed materials equation of state studies. In particular, it focuses on the case of laser shock compressed iron. This work indeed aims at getting to the conditions of the earth's core, comprising a solid inner core and a liquid outer core. The understanding of phenomena governing the core's thermodynamics and the geodynamic process requires the knowledge of iron melting line locus around the solid-liquid interface at 3.3 Mbar. Several experiments were performed to that extent. First, an absolute measurement of iron Hugoniot was obtained. Following is a study of partially released states of iron into a window material: lithium fluoride (LiF). This configuration enables direct access to compressed iron optical properties such as reflectivity and self-emission. Interface velocity measurement is dominated by compressed LiF optical properties and ...

Science.gov (United States)

The ultimate compressive strength of 36 thoracolumbar vertebrae was determined experimentally. In addition, the trabecular bone mineral content was measured by single energy quantitative computed tomography. The areas of fractured endplates were also determined by computed tomography. The results show that a linear relationship exists between the compressive strength and the product of bone density and endplate area. These data allow an in vivo prediction of vertebral body strength using a noninvasive method with a standard error of estimate amounting to less than 0.95 kN. PMID:3212488

Energy Technology Data Exchange (ETDEWEB)

Measurements on laser shock compressed aluminium using the EXAFS (Extended X-ray Absorption Fine Structure) technique on the Al K-edge are described. Two methods of analysis of this data were used for the determination of density: the standard EXAFS technique using Fourier transforms and curve fitting, and a method based on a bandstructure calculation of the absorption spectra as a function of compression. These two techniques give results which are in fairly good agreement with each other and also with a hydrodynamic simulation of the experiment. The ion correlation parameter is estimated and shows that two-sided laser irradiation of aluminium foils produces a dense plasma which is strongly coupled. (author).

British Library Electronic Table of Contents (United Kingdom)

Back pain from osteoporosis is commonly related to compression fractures. The patient with vertebral compression fractures additionally suffers from an ongoing risk of recurrent fractures and postural abnormalities that can result in impaired respiratory function, leading to increased risk of morbidity. Weakened back muscles, especially the back extensor group, are felt to contribute significantly to this risk. The combination of pharmacologic and nonpharmacologic interventions, through physical activity, exercise, and modalities, are potential interventions that could be used to help reduce the pain of osteoporotic compression fractures as well as potentially reducing recurrent fracture rates.

Science.gov (United States)

Ultimate Compressive Strength = 3000.0 psi. 3.0 Failure Criteria. The structural criteria used to evaluate the combustor components was chosen ...

Science.gov (United States)

... by the boron doping in most of the alloys except for Al66Mn9Zr25 + 50 ppm B alloy; permanent deformation at ultimate compressive strength is not ...

UK PubMed Central (United Kingdom)

Nutcracker phenomenon refers to compression of the left renal vein, most commonly between the aorta and the superior mesenteric artery, with impaired blood outflow often accompanied by distention...Full Text Available

Science.gov (United States)

... AGARD AR-319, Volume 2. Knight, D., Zhou ... a Turbulent Boundary Layer in a Supersonic Flow. ... of Development of Separated Flows in Compression ...

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

A long-term follow-up of a patient with beta thalassaemia with intra- and extraspinal extramedullary haematopoietic tissue compressing the spinal cord is presented. Extramedullary haematopoietic nodules are a rare cause of spinal cord compression and should be included in the differential diagnosis, especially in patients from Mediterranean countries. Treatment with radiation therapy solely failed, giving rise to the need of surgical intervention. Surgical decompression of the spine and the removal of the culprit lesion compressing the spine were performed. Postinterventional radiation therapy was applied to the spine. A relapse had to be treated again by surgical means combined with postinterventional radiation therapy. A complete relief of the symptoms and control of the lesion could be obtained.

Science.gov (United States)

Turbine Afterword The SHARP cannon. Hydrogen is compressed in the tube on top, the gun barrel is on bottom. When Jules Verne wrote in 1865 "From Earth to the Moon" he envisioned...

British Library Electronic Table of Contents (United Kingdom)

Heat transfer through the gas diffusion layer (GDL) is a key process in the design and operation of a PEM fuel cell. The analysis of this process requires the determination of the effective thermal conductivity as well as the thermal contact resistance between the GDL and adjacent surfaces/layers. The Part 1 companion paper describes an experimental procedure and a test bed devised to allow separation of the effective thermal conductivity and thermal contact resistance, and presents measurements under a range of static compressive loads. In practice, during operation of a fuel cell stack, the compressive load on the GDL changes. In the present study, experiments are performed on Toray carbon papers with 78% porosity and 5% PTFE under a cyclic compressive load. Results show a significant hy...

Science.gov (United States)

... kg/m3 density. The Rohacell foam displayed an average ultimate compressive strength of 1546 kPa. The maximum load ...

Science.gov (United States)

Traditional composite sandwich panels are composed of inner and outer facesheets separated by a core material such as balsa wood, polymeric foam, ...

Science.gov (United States)

Cardiopulmonary resuscitation - adult; Rescue breathing and chest compressions - adult; Resuscitation - cardiopulmonary - adult ... CPR can be lifesaving, but it is best performed by those who have been trained in an ...

British Library Electronic Table of Contents (United Kingdom)

This paper presents extensive non-linear finite element (FE) analysis and formulation development work carried out on the ultimate compressive strength of plates and stiffened panels of ship structures. A review of contemporary designs for large ships was carried out. The existing formulae for plate ultimate compressive strength were reviewed and compared with non-linear FE analysis results. A semi-analytical formula for ultimate compressive strength assessments of stiffened panels was proposed and is described. The developed formula was verified against results using ABAQUS non-linear FE software for a series of 61 stiffened panels and a good agreement between the proposed formula and FE results were achieved. The method was verified against a large number of published FE results and was ...

Science.gov (United States)

reaching their ultimate compressive strength. Thus, when applying a lamina stress analysis in conjunction with a failure model, one must ...

Science.gov (United States)

> Develoopments which have imporved fuel core quality and reduced production costs are described. These developments in the melting and casting of uranium ingots arei modification of the crucible and knockout-slide assembly, substitution of uncoated crucibles for coated crucibles, and substitution of a one-piece gun barrel mold for a vertically split mold. (N.W.R.)

International Nuclear Information System (INIS)

A technique has been developed for joining a large calcium fluoride crystal to a stainless-steel flange by means of a silver transition ring. The process involves both vacuum brazing using a copper-silver alloy and air brazing using silver chloride. This paper describes the procedure used in fabricating a high-vacuum leak-tight calcium fluoride window assembly.

Energy Technology Data Exchange (ETDEWEB)

In order to judge the potential fluorescent lamp applications of various low-pressure positive column discharges it is necessary to measure the absolute power emitted in the ultraviolet region of the spectrum. For rare-gas discharges the principle emission occurs in the vacuum ultraviolet so that it is difficult to measure the radiant emittance (power per unit area) of the resonance radiation by standard methods. Two independent techniques are discussed for measuring the radiant emittance of positive column discharges in the vacuum ultraviolet. These techniques are used to study xenon positive column discharges at the resonance wavelength of 147 nm. The first method relies on the measurement of the resonance level density by absorption techniques. The effective decay rate of the resonance level is then determined by the simulation of resonance radiation transport. These two quantities are combined to yield the radiant emittance at 147 nm ...

Energy Technology Data Exchange (ETDEWEB)

The current status of the ZTH vacuum liner design is covered by this report. ZTH will be the first experiment to be installed in the CPRF (Confinement Physics Research Facility) at the Los Alamos National Laboratory and is scheduled to be operational at the rated current of 4 MA in 1992. The vacuum vessel has a 2.4 m major radius and a 40 cm minor radius. Operating parameters which drive the vacuum vessel mechanical design include a 300 C bakeout temperature, an armour support system capable of withstanding 25 kV, a high toroidal resistance, 1250 kPa magnetic loading, a 10 minute cycle time, and high positional accuracy with respect to the conducting shell. The vacuum vessel design features which satisfy the operating parameters are defined. The liner is constructed of Inconel 625 and has a geometry which alternates sections of thin walled bellows with rigid ribs. These composite sections span between ...

Energy Technology Data Exchange (ETDEWEB)

Combustion of extremely fuel-rich ({phi}=4) methane/air mixtures at elevated pressures is investigated as a potential means to generate molecular hydrogen by non-catalytic partial oxidation. This system is investigated both computationally and experimentally. The computations use a perfectly-stirred reactor model and an explicit methane cool-flame mechanism to investigate the effects of reactor parameters on reaction time and product composition. Under adiabatic conditions, such mixtures are predicted to autoignite at low temperatures {approx}700 K for pressures exceeding 8.5 atm. Above 15 atm, conversion to products is complete in roughly 1 s. The dependence of reaction time and hydrogen yield is investigated as a function of inlet temperature, system pressure, and flame equivalence ratio. Actual product yields are measured in a tube reactor facility, and many of the predictions of the model, including long relaxation times to chemical equilibrium and temperatures ...

Science.gov (United States)

Recent experiments with TFTR, D-III-D and JET involving the injection and trapping of low density beams of high energy large orbit ions indicate that large orbit non-adiabatic ions slow down and diffuse classically in the presence of anomalous fluctuations and transport of adiabatic majority particles. Accordingly, we consider conceptual fusion reactors(N. Rostoker, M.W. Binderbauer and H.J. Monkhorst, Science) 278, 1419 (1997). based on classical confinement of fuel ions and fusion products(M.W. Binderbauer and N. Rostoker, J. Plasma Phys.) 56, 451 (1996).. The magnetic confinement geometry of the proposed designs is a Field Reversed Configuration. A survey of experimental results on instabilities and their characteristics as related to these reactor concepts is presented. Particular focus will be given to long wavelength (as compared to gyro-radius) and low frequency (?<< c/r_o, r_o=3D major radius of annular current ring) instabilities ...

International Nuclear Information System (INIS)

We have developed a new method for calculating common envelope (CE) events based on explicit consideration of the donor star's structural response to adiabatic mass loss. In contrast to existing CE prescriptions, which specify a priori the donor's remnant mass, we determine this quantity self-consistently and find that it depends on binary and CE parameters. This aspect of our model is particularly important to realistic modeling for upper main-sequence star donors without strongly degenerate cores (and hence without a clear core/envelope boundary). We illustrate the central features of our method by considering CE events involving 10 M_s_u_n donors on or before their red giant branch. For such donors, the remnant core mass can be as much as 30% larger than the star's He-core mass. Applied across a population of such binaries, our methodology results in a significantly broader remnant mass and final orbital separation distribution and a 20% increase in CE survival ...

CERN Document Server

We introduce a cohomological obstruction to solving the constant scalar curvature K\\"ahler (cscK) equation twisted by a semipositive form, appearing in works of Fine and Song-Tian. Geometrically this gives an obstruction for a manifold to be the base of a holomorphic submersion carrying a cscK metric in certain ``adiabatic'' classes. In turn this produces many new examples of general type threefolds with classes which do not admit a cscK representative. When the twist vanishes our obstruction extends the slope stability of Ross-Thomas to effective divisors on a K\\"ahler manifold. Thus we find examples of non-projective slope unstable manifolds.

Energy Technology Data Exchange (ETDEWEB)

We show using covariant techniques that the Einstein static universe containing a perfect fluid is always neutrally stable against small inhomogeneous vector and tensor perturbations and neutrally stable against adiabatic scalar density inhomogeneities so long as c{sup 2}{sub s} > 1/5, and unstable otherwise. We also show that the stability is not significantly changed by the presence of a self-interacting scalar field source, but we find that spatially homogeneous Bianchi type IX modes destabilize an Einstein static universe. The implications of these results for the initial state of the universe and its pre-inflationary evolution are also discussed. (letter to the editor)

Energy Technology Data Exchange (ETDEWEB)

A nitrogen oxides decreasing combustion method comprising: mixing a fuel and air with each other; bringing the mixture obtained into contact with a packed catalyst; and adding a fresh supply of the fuel to the stream obtained to form a mixed gas and causing the mixed gas to undergo non-catalytic thermal combustion, characterized in that only a catalytic reaction or combustion occurs at the packed catalyst; the temperature of the packed catalyst is kept lower than the ignition temperature of the mixture; the adiabatic flame temperature which is reached by the non-catalytic thermal combustion of the mixed gas is lower than the temperature at which the nitrogen oxides occur. 39 figs.

Energy Technology Data Exchange (ETDEWEB)

The problem of efficient capture of nonlinear oscillations into resonance is discussed. The capture is guaranteed by passage through resonance when the system starts in equilibrium and the driving amplitude exceeds a threshold. The threshold problem is described by a universal nonlinear Schroedinger-type equation with a single parameter and cannot be analyzed by perturbation methods. A similar threshold phenomenon is a characteristic of two weakly coupled oscillators with a slow parameter if one of the oscillators starts in equilibrium, allowing efficient capture into resonance and subsequent adiabatic (autoresonant) control of strongly excited nonlinear oscillations.

International Nuclear Information System (INIS)

A formalism for the dynamical treatment of the molecular orbitals of valence nucleons in nucleus-nucleus collisions is developed with the use of the coupled-reaction-channel (CRC) method. The Coriolis coupling effects as well as the finite mass effects of the nucleon are taken into account in this model, of rotating molecular orbitals, RMO. First, the validity of the concept is examined from the viewpoint of the multi-step processes in a standard CRC calculation for systems containing two identical [core] nuclei. The calculations show strong CRC effects particularly in the case where the mixing of different l-parity orbitals - called hybridization in atomic physics - occurs. Then, the RMO representation for active nucleons is applied to the same systems and compared to the CRC results. Its validity is investigated with respect to the radial motion (adiabaticity) and the rotation of the molecular axis (radial and rotational coupling). Characteristic molecular ...

Energy Technology Data Exchange (ETDEWEB)

In this paper structure and mechanical properties of PBZT and PBO fibers are briefly discussed. One limitation of the high-modulus polymeric fibers and ultrahigh-modulus carbon fibers in reinforced composites is their poor compressive strength. Issues related to the compressive strength of polymeric and carbon fibers are considered. 62 references, 7 figures, 4 tables.

Energy Technology Data Exchange (ETDEWEB)

Desiccants have been used in many applications to provide dehumidification. This paper describes an application of desiccants which provide both dehumidification and sensible cooling, with little or no use of conventional vapour-compression refrigeration plant. Through a parametric study, the energy consumption and costs of a desiccant cooling system are compared with those of a conventional vapour-compression refrigeration-based air-conditioning system. (author)

Energy Technology Data Exchange (ETDEWEB)

Since the most efficient way to improve fuel economy in the part-load range is to increase the compression ratio, emphasis is placed on combustion chambers allowing high compression ratios combined with low octane requirements. According to Porsche experience, many demands can be met in the simplest manner by locating the combustion chamber in the piston crown. This configuration offers various advantages over its counterpart installed in the cylinder head. 24 refs.

Energy Technology Data Exchange (ETDEWEB)

Swirling speed in a direct injection diesel engine was measured by a laser doppler velocimeter. Intake port geometry and engine speed were changed as factors affecting the swirling flow to study the distribution of swirling flow speed. The distribution of swirling flow speed changes complicatedly owing to axial nonsymmetry during intake process but becomes simple shape of axial symmetry during compression process after closing intake valve. But if this is assumed as the rigid swirl shape, the difference due to each intake port cannot be expressed but also large error may be possible to appear close to the cylinder wall. The distribution of swirling flow speed during compression process changes similarly, nearly proportinal to engine speed. But the similarity is higher at the middle period in compression process than at the end period in compression period. Axial distribution of local swirling ratio ...

Energy Technology Data Exchange (ETDEWEB)

Suppliers of systems and components for compressed air technique were shown at the Hanover Fair 94 in Hall 5. On about 6000 m{sup 2} floor area, they showed their product range, which covered the whole range of compressed air technique from compressors via equipment for providing and storing the compressed air to compressed air tools. (orig.) [Deutsch] Die Anbieter von Systemen und Komponenten fuer die Drucklufttechnik waren auf der Hannover-Messe `94 in der Halle 5 zu finden. Dort zeigten sie auf rund 6000 m{sup 2} ihre Produktpalette, die von Kompressoren ueber die Geraete zum Aufbereiten und Speichern der Druckluft bis zu Druckluftwerkzeugen reichte und den gesamten Bereich der Drucklufttechnik abdeckte. (orig.)

International Nuclear Information System (INIS)

On all steam turbines operating with condensation the air leakage penetrating from the part of the plant which is under vacuum must be eliminated, in order to maintain the vacuum created by physical conditions. In order to attain effective air bleed-off, the water-steam-air mixture is conveyed via the super-cooling bundles in the condenser. In this way the steam partial pressure decreases and the air partial pressure increases at a constant condenser pressure. In this procedure the mixture is supercooled by about 4"0C compared with the saturate steam temperature appertaining to the condenser pressure. The values of volume of air leakage are the result of a year's experience on existing plant. (orig.).

CERN Document Server

One hope to solve the cosmological constant problem is to identify a symmetry principle, based on which the cosmological constant can be reduced either to zero, or to a tiny value. Here, we note that requiring that the vacuum state is Lorentz invariant significantly reduces the theoretical value of the vacuum energy density. Hence, this also reduces the discrepancy between the observed value of the cosmological constant and its theoretical expectation, down from 123 orders of magnitude to 56 orders of magnitude. We find that, at one loop level, massless particles do not yield any contribution to the cosmological constant. Another important consequence of Lorentz symmetry is stabilization of the gravitational hierarchy: the cosmological constant (divided by Newton's constant) does not run as the quartic power of the renormalization group scale, but instead only logarithmically.

British Library Electronic Table of Contents (United Kingdom)

We have measured time-resolved laser-induced incandescence of flame-generated soot under high-vacuum conditions (4.1?10?6 mbar) at an excitation wavelength of 532 nm with laser fluences spanning 0.06?0.5 J/cm2. We generated soot in an ethylene/air diffusion flame, introduced it into the vacuum system with an aerodynamic lens, heated it using a pulsed laser with a spatially homogeneous and temporally smooth laser profile, and recorded LII temporal profiles at 685 nm. At low laser fluences LII signal decay rates are slow, and LII signals persist beyond the residence time of the soot particles in the detection region. At these fluences, the temporal maximum of the LII signal increases nearly linearly with increasing laser fluence until reaching a plateau at ?0.18?J/cm2. At higher fluences, th...

CERN Document Server

We study from a critical perspective several quantum-electrodynamic phenomena commonly related to vacuum electromagnetic (EM) fluctuations in complex media. We compute the resonance-shift, the spontaneous emission rate, the local density of states and the van-der-Waals-Casimir pressure in a dielectric medium using a microscopic diagrammatic approach. We find, in agreement with some recent works, that these effects cannot be attributed to variations on the energy of the EM vacuum but to variations of the dielectric self-energy. This energy is the result of the interaction of the bare polarizability of the dielectric constituents with the EM fluctuations of an actually polarized vacuum. We have found an exact expression for the spectrum of these fluctuations in a statistically homogeneous dielectric. Those fluctuations turn out to be different to the ones of normal radiative modes. It is the latter that carry the ...

International Nuclear Information System (INIS)

A scheme is presented for the generation of entangled states for two cavity mirrors. In the scheme each mirror initially in a vacuum state interacts with a weak coherent field, resulting in a photon-number dependent kick. The detection of a photon leaking from the cavities collapses the two mirrors to an entangled state.

International Nuclear Information System (INIS)

A Monte Carlo simulation of the vacuum Bianchi type-IX (mixmaster) cosmology yields a significant correlation between large universe volume and high anisotropy. An analog of the model's chaotic classical behavior is seen in the break up of the universe wave function at large volume into fingers in the corners of the minisuperspace anisotropy potential.

Science.gov (United States)

Spontaneous radiation by an atom in a Rydberg state is inhibited by use of parallel conducting planes to eliminate the vacuum modes at the transition frequency. Spontaneous radiation emission is observed to turn off abruptly at the cutoff frequency of the waveguidelike structure, and the natural lifetime is measured to increase by a factor of at least 20.

Energy Technology Data Exchange (ETDEWEB)

This paper describes the technical design and performance of the diagnostic system installed in the tokamak TCABR to measure parameters of the plasma edge. The system consists of four Langmuir probes under remote control. (author)

International Nuclear Information System (INIS)

Plasma surface interactions in tokamaks are known to create significant quantities of dust, which settles onto surfaces and accumulates in the vacuum vessel. In ITER, a loss of vacuum accident may result in the release of dust which will be radioactive and/or toxic, and provides increased surface area for chemical reactions or dust explosion. A new method of analysis has been developed for modeling dust resuspension and transport in loss of vacuum accidents. The aerosol dynamic equation is solved via the user defined scalar (UDS) capability in the commercial CFD code Fluent. Fluent solves up to 50 generic transport equations for user defined scalars, and allows customization of terms in these equations through user defined functions (UDF). This allows calculation of diffusion coefficients based on local flow properties, inclusion of body forces such as gravity and thermophoresis in the convection term, and user defined ...

UK PubMed Central (United Kingdom)

The recovery of schistosome cercariae from natural waters has been limited by variations in turbidity and in the accuracy of recovery with different techniques. A modification of the Rowan vacuum paper...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Additional results using a calorimetric technique for measuring the total hemispherical emittance of pipe surfaces from 400 to 600 K are described. Two different Pyrex pipe enclosures were used, one of 15 cm i.d. and the other of 30 cm i.d. An error analysis showed that the larger diameter Pyrex pipe should have a smaller error, but the difference was negligible for the 4.4-cm test pipe diameter used. Measurements on a short length of a previously-measured pipe agreed with earlier measurements, but only over the temperature range of the measurements. While the technique normally uses a vacuum to minimize nonradiative heat transfer, measurements were done succesfully with an argon atmosphere in a closed system. A nickel-plated pipe, measured first in a vacuum and then in an argon atmosphere, allowed calculation of an effective convective heat-transfer coefficient for use with test pipes of unknown emittances. Measurements done with an atmosphere ...

International Nuclear Information System (INIS)

We simplify and generalize an argument due to Bowcock and Watts showing that one can associate a finite Lie algebra (the 'classical vacuum preserving algebra') containing the Moebius sl(2) subalgebra to any classical W-algebra. Our construction is based on a kinematical analysis of the Poisson brackets of quasi-fields. In the case of the W_S"G-subalgebra S of a simple Lie algebra G, we exhibit a natural isomorphism between this finite Lie algebra and G whereby the Moebius sl(2) is identified with S. (orig.).

British Library Electronic Table of Contents (United Kingdom)

Thermal desorption spectroscopy (TDS) was used to study outgassing from polycrystalline SiGe (poly-SiGe), SiC and SiO"2 films used for poly-SiGe-based MEMS thin film vacuum package technology. Primary desorption products were found to be H"2, H"2O and CO"2. The CO"2 outgassing could be correlated with CF"4 plasma interface cleaning used for thick SiGe PECVD, which can leave carbon at the CF"4-plasma-cleaned interface.

Energy Technology Data Exchange (ETDEWEB)

The main results of earlier work by the author, Sushko, and Khoruzhii describing the algebraic structure of quantum-field systems with (discrete) vacuum superselection rules are generalized to the large class of Wightman theories with essentially self-adjoint field operators (a very strong restriction was imposed on the theory, namely, that the polynomial Op algebra of the Wightman fields /rho/ belongs to the class II, i.e., /rho/ /sub s'/ =/rho/ /sub w'/). It is also shown that the field Op algebra of a Wightman theory with discrete vaccum superselection rule possesses a class II extension.

CERN Document Server

If quantum fields exist in extra compact dimensions, they will give rise to a quantum vacuum or Casimir energy. That vacuum energy will manifest itself as a cosmological constant. The fact that supernova and cosmic microwave background data indicate that the cosmological constant is of the same order as the critical mass density to close the universe supplies a lower bound on the size of the extra dimensions. Recent laboratory constraints on deviations from Newton's law place an upper limit. The allowed region is so small as to suggest that either extra compact dimensions do not exist, or their number is about to be tightly constrained by experimental data.

Energy Technology Data Exchange (ETDEWEB)

The heavy crude fraction processing is performed under very high vacuum to minimize thermal cracking which cause coke deposition and damage the equipment. The current tendency is to process heavier oil leading to higher process temperatures and consequently to greater fouling. This situation demands better knowledge fouling process by carbonization. This problem is pronounced in the residual gasoil region of a vacuum distillation unit because it obstructs the recirculation circuits and the spray system with serious environmental and economics implications. This paper review the main correlated published work related to coke generation and fouling and presents a discussion about the works. (author)

International Nuclear Information System (INIS)

We consider the dynamics toward the initial singularity of Bianchi type IX vacuum and orthogonal perfect fluid models with a linear equation of state. The 'Bianchi type IX attractor theorem' states that the past asymptotic behavior of generic type IX solutions is governed by Bianchi type I and II vacuum states (Mixmaster attractor). We give a comparatively short and self-contained new proof of this theorem. The proof we give is interesting in itself, but more importantly it illustrates and emphasizes that type IX is special, and to some extent misleading when one considers the broader context of generic models without symmetries.

Energy Technology Data Exchange (ETDEWEB)

This paper describes an innovative use of post-consumer waste HDPE plastic in concrete as a soft filler. A reference concrete was proportioned to have the 28-day compressive strength of 5000 psi (35 MPa). A high-density plastic was shredded into small particles for use in the concrete. These particles were subjected to three chemical treatments (water, bleach, bleach + NaOH) to improve their bonding with the cementitious matrix. The plastic particles were added to the concrete in the range of 0--5% of total mixture by weight. Compressive strengths were measured for each test mixture. The results showed that chemical treatment has a significant effect on performance of the plastic filler in concrete. Of the three treatments used on the plastic, the best performance was observed with the alkaline bleach treatment (bleach + NaOH) with respect to compressive strength of concrete.

British Library Electronic Table of Contents (United Kingdom)

Free form fabrication and high resolution imaging techniques enable the creation of biomimetic tissue engineering scaffolds. A 3D CAD model of canine trabecular bone was produced via micro CT and exported to a fused deposition modeler, to produce polybutylene terephthalate (PBT) trabeculated scaffolds and four other scaffold groups of varying pore structures. The five scaffold groups were divided into subgroups (n=6) and compression tested at two load rates (49?N/s and 294?N/s). Two groups were soaked in a 25??C saline solution for 7?days before compression testing. Micro CT was used to compare porosity, connectivity density, and trabecular separation of each scaffold type to a canine trabecular bone sample. At 49?N/s the dry trabecular scaffolds had a compressive stiffness of 4.94?1.19?MP...

British Library Electronic Table of Contents (United Kingdom)

A testing methodology, which includes the evaluation of free sintering strain, stress-induced dimensional changes, and weight changes, was developed to determine the critical dimensional changes and thermomechanical response during presintering (i.e., before densification). The effects of organic binder burnout, decomposition of phases, and phase changes on the thermomechanical behavior of a ceramic green body, consisting of methylcellulose as a binder, gibbsite, silica, and alumina, were studied. The compressive stress-strain behavior was found to be nonlinear. The average compressive and tensile strengths of the sample at room temperature were -14.5 and 1.06 MPa, respectively. Both the compressive and tensile strengths decrease by two orders of magnitude with the increasing temperature a...

Science.gov (United States)

The bone mineral content of 109 lumbar vertebrae from 36 different subjects was determined by dual photon absorptiometry. The mean age of the subjects was 58.5 years (range, 31 to 79 years). The ultimate strength of the vertebral bodies was determined during axial compression. Bone mineral content and ultimate compressive strength were correlated (r = 0.86) and the strength was found to increase linearly with increasing amounts of bone mineral content. No differences in this correlation were found in the four vertebral levels (L-4) included in the study, but a difference in this correlation was found between specimens taken from male and female subjects. The results make it possible to estimate the strength of a vertebral body from the knowledge of its bone mineral content as determined by dual photon absorptiometry and provide a basis of estimations of normal and abnormal amounts of bone mineral content in the vertebrae of the lumbar spine. ...

Science.gov (United States)

Ni-free shape memory alloys are promising functional materials for medical applications. A newly developed Ti-Mo based shape memory alloy shows superelasticity after thermomechanical treatment. However, the microstructure evolution and precipitation during thermomechanical processes are still not well understood. In the present paper, compressive deformation behavior at a series of temperatures of 298K - 973K and tensile deformation behavior of the alloy after aged at 573K - 973K have been investigated systematically. It is found that the compressive yield stress and ultimate compressive strength change with the deformation temperature. The ultimate tensile strength and yield stress of aged specimens also change with the aging temperature following a non-linear relationship. Microstructures of aged specimens as well as effects of lattice softening and aging-induced precipitates on the deformation behavior have been ...

Energy Technology Data Exchange (ETDEWEB)

The combustion characteristics of a turbocharged natural gas and diesel dual-fuelled compression ignition (CI) engine are investigated. With the measured cylinder pressures of the engine operated on pure diesel and dual fuel, the ignition delay, effects of pilot diesel and engine load on combustion characteristics are analysed. Emissions of HC, CO, NO{sub x} and smoke are measured and studied too. The results show that the quantity of pilot diesel has important effects on the performance and emissions of a dual-fuel engine at low-load operating conditions. Ignition delay varies with the concentration of natural gas. Smoke is much lower for the developed dual-fuel engine under all the operating conditions. (Author)

British Library Electronic Table of Contents (United Kingdom)

This paper deals with steel fiber reinforced concrete mechanical static behaviour and with its classification with respect to fibers content and mix-design variations. A number of experimental tests were conducted to investigate uniaxial compressive strength and tensile strength. Different mixtures were prepared varying both mix-design and fiber length. Fibers content in volume was of 1% and 2%. Mechanical characterization was performed by means of uniaxial compression tests with the aim of deriving the ultimate compressive strength of fiber concrete. Four-point bending tests on notched specimens were carried out to derive the first crack strength and the ductility indexes. The tensile strength of steel fiber reinforced concrete (SFRC) was obtained both from an experimental procedure and b...

Energy Technology Data Exchange (ETDEWEB)

Investigations of superdense compression touch on such problems as ultrahigh-frequency oscillations of matter in the generation of gravitational waves, the powerful pumping of hard coherent radiation, and the laboratory simulation of stellar interiors. This paper reviews the theory of supercompression and discusses some experiments involving multifoil collision supercompression.

UK PubMed Central (United Kingdom)

Spontaneous spinal epidural hematoma is a rare cause of acute spinal cord compression. A 25-year-old male presented with a history of sudden onset of complete quadriplegia with sensory loss below the...Full Text Available

International Nuclear Information System (INIS)

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

UK PubMed Central (United Kingdom)

AbstractListeners show remarkable flexibility in processing variation in speech signal. One striking example is the ease with which they adapt to novel speech distortions such as listening...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

A case of {beta}-thalassemia intermedia with spinal cord compression due to extramedullary hematopoiesis, which was successfully treated by blood transfusion, is presented. Emphasis was made on the MRI appearance of extramedullary hematopoiesis on different pulse sequences. The theories that aimed to explain the involvement of the epidural space by extramedullary hematopoiesis are discussed.

Science.gov (United States)

The goal of this study was to evaluate topics used to troubleshoot circuit boards with known or suspected thermally intermittent components. Failure modes for thermally intermittent components are typically mechanical defects, such as cracks in solder paths or joints, or broken b...

Energy Technology Data Exchange (ETDEWEB)

A natural gas and diesel dual-fuel turbocharged compression ignition (CI) engine is developed to reduce emissions of a heavy-duty diesel engine. The compressed natural gas (CNG) pressure regulator is specially designed to feed back the boost pressure to simplify the fuel metering system. The natural gas bypass improves the engine response to acceleration. The modes of diesel injection are set according to the engine operating conditions. The application of honeycomb mixers changes the flowrate shape of natural gas and reduces hydrocarbon (HC) emission under low-load and lowspeed conditions. The cylinder pressures of a CI engine fuelled with diesel and dual fuel are analysed. The introduction of natural gas makes the ignition delay change with engine load. Under the same operating conditions, the emissions of smoke and NO{sub x} from the dual-fuel engine are both reduced. The HC and CO emissions for the dual-fuel engine remain within the range ...

UK PubMed Central (United Kingdom)

BackgroundLignocellulosic biomass such as wood is an attractive material for fuel ethanol production. Pretreatment technologies that increase the digestibility of cellulose and hemicellulose...Full Text Available

Science.gov (United States)

... yourself to call 911 until you have performed CPR for about 2 minutes. 3. Carefully place the ... more breaths. The chest should rise. 9. Continue CPR (30 chest compressions followed by 2 breaths, then ...

Science.gov (United States)

The bone mineral areal content and the ultimate compressive strength were determined in 109 lumbar vertebrae from 36 subjects. The bone mineral areal content was related to the number, shape, and localization of the Schmorl's nodes detected in the x-rayed and sectioned vertebral bodies. One type of node, irregular in shape and localization, occurred only in the vertebrae with low bone mineral areal content values and thus in vertebrae with relatively low compressive strength. A second type of Schmorl's nodes, regular in shape and localization, did not reflect any general weakness of the vertebral bodies. PMID:6623194

CERN Document Server

The phase transition is a performance measure of the sparsity-undersampling tradeoff in compressed sensing (CS). This letter reports, for the first time, the existence of an exact phase transition for the $\\ell_1$ minimization approach to the complex valued CS problem. This discovery is not only a complementary result to the known phase transition of the real valued CS but also shows considerable superiority of the phase transition of complex valued CS over that of the real valued CS. The results are obtained by extending the recently developed ONE-L1 algorithms to complex valued CS and applying their optimal and iterative solutions to empirically evaluate the phase transition.

International Nuclear Information System (INIS)

The method of syndrome coding for data compression read out from multiwire proportional chambers that has been previously proposed is generalized in case of its application to registration of the coordinates of events detected. The questions of execution of arithmetic and algebraic operations on the Galois field elements and their hardware implementation are considered. The method of computation is presented of a specialized processor for parallel computing the coordinates of three sparks. The estimate of its speed is equal to 185 ns. Data compression, data selection and coordinate calculations are performed without use of memory elements and timing pulses.

Energy Technology Data Exchange (ETDEWEB)

A method and apparatus for operating a compression ignition engine having a cylinder wall, a piston, and a head defining a combustion chamber. The method and apparatus includes delivering fuel substantially uniformly into the combustion chamber, the fuel being dispersed throughout the combustion chamber and spaced from the cylinder wall, delivering an oxidant into the combustion chamber sufficient to support combustion at a first predetermined combustion duration, and delivering a diluent into the combustion chamber sufficient to change the first predetermined combustion duration to a second predetermined combustion duration different from the first predetermined combustion duration.

Energy Technology Data Exchange (ETDEWEB)

The increase of the compression ratio of Otto carburator engines up to epsilon = 14 was investigated by Audi in its research department at Neckarsulm. The results are presented in three partial reports. Part one describes the Audi fuel method and demonstrates the effects of the main parameters. Part two shows the influence of the current on the combustion by the help of a new measuring method developed by the Institut fuer Physikalische Elektronik at Stuttgart University. Part three provides a theoretical analysis of the data gained in the investigations.

Energy Technology Data Exchange (ETDEWEB)

Micro-compression specimens, 1O-15{mu}m in diameter by 20-30{mu}m in height, were produced from individual parent grains in a polycrystalline U-13at%Nb shape-memory alloy using the focused ion beam (FIB) technique. The specimens were tested in a nanoindentation instrument with a flat diamond tip to investigate stress-strain behavior as a function of crystallographic orientation. The results are in qualitative agreement with a single-crystal accommodation strain (Bain strain) model of the shape-memory effect for this alloy.

International Nuclear Information System (INIS)

We consider a SQUID ring inductively coupled to an electromagnetic field mode, both treated quantum mechanically. We demonstrate a method for creating a maximally entangled state between the ring and the field mode. Our method utilises a non-adiabatic external magnetic flux pulse to move into and out of a transition region. Hence, our approach is fundamentally different to techniques based on Landau-Zener tunnelling that can also be used to achieve similar results. Our analysis is extended to include the effects of coupling the system to a dissipative environment. With this model we show that although such an environment makes a noticeable difference to the time evolution of the system, it need not destroy the entanglement of this coupled system over time scales required for quantum technologies.

International Nuclear Information System (INIS)

Favorable reaction channels are searched for in order to obtain the superheavy element "2"9"8114. The interaction energy is supposed to comply with the adiabatic hypothesis. Concerning the deformation energy, a very complete binary macroscopic-microscopic energy method is used to perform calculations. Deformed two-center shell model provides the energy level schemes for shell effects. Yukawa-plus-exponential model gives the macroscopic (liquid drop) part of the total energy. The mass tensor is obtained by the Werner-Wheeler irrotational flow hypothesis. Finally the minimization of the multidimensional action integral produces the highest penetrability values. Kr-projectile reactions provide the best pairs, although generally the presentabilities are very low. (author)

International Nuclear Information System (INIS)

A detailed treatment is introduced to measure the dynamic stability of the relativistic electrons in a self-amplified spontaneous emission free-electron laser (FEL) system, which includes the numerical approach of the Kolmogorov entropy (entropy-like quantity), the general equations of motion for a charged particle and the method of monitoring the simulation accuracy. Numerical experiments reveal a new phenomenon that there exists the possibility of the transition from chaotic to non-chaotic phase-space trajectories of the strongly relativistic electrons due to the effect of their self-fields. The adiabatic magnetic field of a one-dimensional wiggler may have a slight influence on the electron transportation in the absence of the FEL fields, but substantially affects the dynamic stability of the electrons in the process of the FEL interaction. Moreover, the laser fields diminish the dynamic stability of the electrons as the FEL interaction grows exponentially.

Energy Technology Data Exchange (ETDEWEB)

Atmospheric pressure tests were performed in which a palladium catalyst ignites and stabilizes the homogeneous combustion of methane. Palladium exhibited a reversible deactivation at temperatures above 750 C, which acted to ``self-regulate`` its operating temperature. A properly treated palladium catalyst could be employed to preheat a methane/air mixture to temperatures required for ignition of gaseous combustion (ca. 800 C) without itself being exposed to the mixture adiabatic flame temperature. The operating temperature of the palladium was found to be relatively insensitive to the methane fuel concentration or catalyst inlet temperature over a wide range of conditions. Thus, palladium is well suited for application in the ignition and stabilization of methane combustion.

Energy Technology Data Exchange (ETDEWEB)

The application of a method for determining the temperature of an oxygen-replenished air stream heated to 2600 K by a hydrogen burner is reviewed and discussed. The purpose of the measurements is to determine the spatial uniformity of the temperature in the core flow of a ramjet test facility. The technique involves sampling the product gases at the exit of the test section nozzle to infer the makeup of the reactant gases entering the burner. Knowing also the temperature of the inlet gases and assuming the flow is at chemical equilibrium, the adiabatic flame temperature is determined using an industry accepted chemical equilibrium computer code. Local temperature depressions are estimated from heat loss calculations. A description of the method, hardware and procedures is presented, along with local heat loss estimates and uncertainty assessments. The uncertainty of the method is estimated at {+-}31 K, and the spatial uniformity was measured within {+-}35 K.

Energy Technology Data Exchange (ETDEWEB)

As a general approach to the problem of precursive behavior in alloys that undergo a displacive transformation, defect theories are becoming increasingly popular. However, the microscopic origin of the proposed defects is usually not considered. Yu and Anderson (1984) have argued that properties of strong-coupling superconductors, such as the A-15 compounds, imply a breakdown of Migdal's theorem (the adiabatic, or Born-Oppenheimer approximation for separation of electrons and phonons) in these systems. The electron-phonon coupling is so strong that it must be incorporated already in zeroth order. This is the basis for local phonon models, in which the electron-phonon coupling provides an effective double well potential for a localized group of atoms. The Yu-Anderson model and an analogous local Jahn-Teller model (Abell, 1983) are reviewed in connection with displacive transformations in strong-coupling alloys.

British Library Electronic Table of Contents (United Kingdom)

The magnetic three spin-1/2 model for nanometer-scale molecular cluster V15 is analyzed with the emphasis on the origin of the mixing of different spin levels in the resonance fields that is generally important for the problem of single molecular magnets. The zero-field splitting in the ground quadruplet (two Formula Not Shown levels) is shown to depend mainly on the normal component of AS exchange meanwhile the zero-field splitting in the excited Formula Not Shown multiplet is a second order effect with respect to in-plane components of AS exchange. The normal component of the AS exchange is shown to lead to the exact crossing of the magnetic sublevels at the arbitrary direction of the field. The positions of two crossing/anticrossing points in the ground manifold depend mainly on the iso...

Science.gov (United States)

Purpose: To determine the rankings of 6 input-output functions for understanding low-level, conversational, and high-level speech in multitalker babble without manipulating volume control for listeners with normal hearing, flat sensorineural hearing loss, and mildly sloping sensorineural hearing loss. Method: Peak clipping, compression limiting, and 4 wide dynamic range compression (WDRC) input-output functions were compared in a repeated-measure design. Interactions among the compression characteristics were minimized. Speech and babble were processed and recorded at 3 input levels: 45, 65, and 90 dB sound pressure level. Speech recognition of 3 groups of listeners (n = 6/group) was tested for speech processed by each input-output function and at each input level. Results: Input-output functions that made low-level speech audible and high-level speech less distorted by avoiding peak clipping or severe ...

Energy Technology Data Exchange (ETDEWEB)

Data produced by large scale scientific simulations, experiments, and observations can easily reach tera-bytes in size. The ability to examine data-sets of this magnitude, even in moderate detail, is problematic at best. Generally this scientific data consists of multivariate field quantities with complex inter-variable correlations and spatial-temporal structure. To provide scientists and engineers with the ability to explore and analyze such data sets we are using a twofold approach. First, we model the data with the objective of creating a compressed yet manageable representation. Second, with that compressed representation, we provide the user with the ability to query the resulting approximation to obtain approximate yet sufficient answers; a process called adhoc querying. This paper is concerned with a wavelet modeling technique that seeks to capture the important physical characteristics of the target scientific data. Our approach is ...

Energy Technology Data Exchange (ETDEWEB)

The simulation of the Auxiliary Charcoal Bed (ACB) Vacuum System was performed to evaluate the original vacuum system design, detect and identify design deficiencies, investigate the effects of proposed corrections on system performance, and generally aid in refining the system design before construction and mockup testing. The simulation was performed by using the Advanced Continuous Simulation Language (ACSL). The vacuum system design goals are to provide approximately 20 SCFM of both booster gas and purge gas through the system and maintain a flow of approximately 40 SCFM with a velocity of 50 to 75 f/sec at the entrance to the cyclone separator. The model results showed that the original system design was incapable of meeting the system performance goals. Further simulations showed that the following modifications to the original vacuum system design were required to make the system performance ...

Energy Technology Data Exchange (ETDEWEB)

The waste tail gas fuel emitted from refinery plant in Taiwan e.g. catalytic reforming unit, catalytic cracking unit and residue desulfurization unit, was recovered and reused as a replacement fuel. In this study, it was slowly added to the fuel stream of a heater furnace to replace natural gas for powering a full-scale distillation process. The waste tail gas fuel contained on average 60 mol% of hydrogen. On-site experimental results show that both the flame length and orange-yellowish brightness decrease with increasing proportion of waste gas fuel in the original natural gas fuel. Moreover, the adiabatic flame temperature increases as the content of waste gas fuel is increased in the fuel mixture since waste gas fuel has a higher adiabatic flame temperature than that of natural gas. The complete replacement of natural gas by waste gas fuel for a heater furnace operating at 70% loading (i.e. 3.6 x 10{sup 7} kcal/h of combustion capacity) will ...

Energy Technology Data Exchange (ETDEWEB)

The interfacial area transport equation dynamically models the two-phase flow regime transitions and predicts continuous change of the interfacial area concentration along the flow field. Hence, when employed in the numerical thermal-hydraulic system analysis codes, it eliminates artificial bifurcations stemming from the use of the static flow regime transition criteria. Accounting for the substantial differences in the transport phenomena of various sizes of bubbles, the two-group interfacial area transport equations have been developed. The group 1 equation describes the transport of small-dispersed bubbles that are either distorted or spherical in shapes, and the group 2 equation describes the transport of large cap, slug or churn-turbulent bubbles. The source and sink terms in the right-hand-side of the transport equations have been established by mechanistically modeling the creation and destruction of bubbles due to major bubble interaction mechanisms. In the present paper, the ...

Energy Technology Data Exchange (ETDEWEB)

We revisited the quantum Zeno paradox, which claims that a generic quantum system prepared in a state which is not an eigenstate of the Hamiltonian operator and is continuously observed never decays. Since any perfectly isolated quantum system always interact with a vacuum field, we analyze the possibility of using this fact to solve the above mentioned conceptual problem. Therefore we discuss a two-level system or qubit-Bose field interaction Hamiltonians. We consider the quantum dynamics of this two-level system, prepared in the excited state interacting with a Bose field prepared in the Poincare invariant vacuum state. Using a first-order approximation in time-dependent perturbation theory, we evaluate the probability of spontaneous decay of the two-level system driven by the vacuum field. This probability is evaluated for a finite time interval. Using the standard argument to obtain the quantum Zeno paradox, we consider ...

Energy Technology Data Exchange (ETDEWEB)

Aiming to realize ball bearings operable in a vacuum and under high temperature, silicon nitride (Si3N4) ceramic ball bearings were tested. The tested ball bearings were angular contact ball bearings composed of silicon nitride with sputtered molybdenum disulfide coating using a retainer of hot-pressed self-lubricating composite material. The time variation of the frictional torque was examined for the operations under the conditions at 500{degree}C in a vacuum at a rotational speed of 600 rpm and 50N thrust load for 5{times}10{sup 7}revolutions (1400 hours) and for 1.5{times}10{sup 8}revolutions (4200 hours). Excellent tribological performance was obtained. The ball bearings are lubricated with the molybdenum disulfide film at the initial stage of the operation and with a transfer film formed from the retainer material to the balls. In a test at 650{degree}C, low and stable frictional torque was observed up to 500 hours of operation as of the ...

Energy Technology Data Exchange (ETDEWEB)

The decays of charmed mesons into two body nonleptonic final states are investigated. Weak interaction amplitudes of interest in these decays are extracted from lattice four-point correlation functions using a effective weak Hamiltonian including effects to order G{sub f} in the weak interactions yet containing effects to all orders in the strong interactions. The lattice calculation allows a quantitative examination of non-spectator processes in charm decays helping to elucidate the role of effects such as color coherence, final state interactions and the importance of the so called weak annihilation process. For D {yields} K{pi}, we find that the non-spectator weak annihilation diagram is not small, and we interpret this as evidence for large final state interactions. Moreover, there is indications of a resonance in the isospin {1/2} channel to which the weak annihilation process contributes exclusively. Findings from the lattice calculation are compared to results from the continuum ...

British Library Electronic Table of Contents (United Kingdom)

For almost 150 years, the two monotypic genera Trochodendron and Tetracentron (Trochodendraceae) have been considered to share an unusual and primitive feature in angiosperms - the lack of vessels in their wood. Therefore, they have been classified in a basal position in the angiosperms. Our observations by light microscopy, low-vacuum environmental scanning electron microscopy (ESEM) and high-vacuum scanning electron microscopy (SEM) both in fresh and FAA-fixed materials consistently showed the presence of tracheary elements differentiated into two types in both genera. In Trochodendron, the tracheary elements can be divided into perforate vessel elements and imperforate fiber-tracheids and tracheids. The vessel elements show end and lateral walls. The pits on the end walls are elongate- ...

CERN Document Server

We formulate a complete theory of Edge Radiation based on a novel method relying on Fourier Optics techniques. Similar types of radiation like Transition Undulator Radiation are addressed in the framework of the same formalism. Special attention is payed in discussing the validity of approximations upon which the theory is built. Our study makes consistent use of both similarity techniques and comparisons with numerical results from simulation. We discuss both near and far zone. Physical understanding of many asymptotes is discussed. Based on the solution of the field equation with a tensor Green's function technique, we also discuss an analytical model to describe the presence of a vacuum chamber. In particular, explicit calculations for a circular vacuum chamber are reported. Finally, we consider the use of Edge Radiation as a tool for electron beam diagnostics. We discuss Coherent Edge Radiation, Extraction of Edge Radiation by a mirror, and ...

Science.gov (United States)

We study a two-level atom in interaction with a real massless scalar quantum field in a spacetime with a reflecting boundary. The presence of the boundary modifies the quantum fluctuations of the scalar field, which in turn modifies the radiative properties of atoms. We calculate the rate of change of the mean atomic energy of the atom for both inertial motion and uniform acceleration. It is found that the modifications induced by the presence of a boundary make the spontaneous radiation rate of an excited inertial atom oscillate near the boundary and this oscillatory behavior may offer a possible opportunity for experimental tests for geometrical (boundary) effects in flat spacetime. While for accelerated atoms, the transitions from ground states to excited states are found to be possible even in a vacuum due to changes in the vacuum fluctuations induced by both the presence of the boundary and the acceleration of atoms, and this can be ...

International Nuclear Information System (INIS)

For shut-down safety of the turbine generator (securing of auxiliary power operation after load shut-down and preventing the reaching of overspeed after load shut-down with disturbed turbine governing system) additional measures compared to those for superheated steam turbines are required for turbine generators in plants with pressurized water reactor (PWR) as well as those with boiling water reactor (BWR) . Equipment is described (e.g. overspeed govern or selecting connection, vacuum breaker, bypass valves, intercepting valves) which, depending on the own conditions of the individual turbine generator (e.g. run-up time, vacuum, enclosed energy), may be applied alone or in jointly. (orig.).

CERN Document Server

In the beam pipe of the positron damping ring of the Next Linear Collider, electrons will be created by beam interaction with the surrounding vacuum chamber wall and give rise to an electron cloud. Several solutions are possible for avoiding the electron cloud, without changing the bunch structure or the diameter of the vacuum chamber. Some of the currently available solutions for preventing this spurious electron load include reducing residual gas ionization by the beam, minimizing beam photon-induced electron production, and lowering the secondary electron yield (SEY) of the chamber wall. We will report on recent SEY measurements performed at SLAC on TiN coatings and TiZrV non-evaporable getter thin films.

International Nuclear Information System (INIS)

Twelve powders of TiO_2-Y_2O_3-ZrO_2 solid solution of the methodically changed composition were prepared by a coprecipitation-calcination technique. After mixing with phenol-formaldehyde resin, the powders were calcinated for 2 hours at 1200"oC in vacuum. The resultant composite powders contained TiC and non-reacted carbon. Green compacts were sintered in vacuum at 1500"oC for 2 hours. A temperature increase was stopped at 1200"oC to react remains of carbon. There were two carbides in the composites TiC and ZrC. TiC non-stoichiometry depended on carbon content in the system. Phase composition of the depended on of titania and yttria in zirconia solid solution. The majority of the samples showed two tetragonal zirconia phases differing in lattice parameter and tetragonality. (author)

Science.gov (United States)

This paper discusses the mechanisms of gas breakdown at low values of pressure and inter-electrode gap, i.e. in the vicinity of the Paschen minimum. In this area of pressure and inter-electrode gap values, breakdown occurs either through gas or vacuum mechanisms, and also the so called anomalous Paschen effect appears. Electrical breakdown of electropositive, electronegative and noble gases has been investigated theoretically, experimentally and numerically. Based on the results obtained, regions in which particular breakdown mechanisms appear have been demarcated. Special attention has been devoted to the anomalous Paschen effect as well as to the avalanche vacuum breakdown mechanism.

Energy Technology Data Exchange (ETDEWEB)

Within the framework of the Bianchi type-IX homogeneous space, we set up a system of coupled equations for the cosmic scale factors, scalar field, and radiative energy density. At the tree level, the equations are written in a self-consistent, Hartree-Fock form. For phi/sup 4/ theory, the system of nine first-order differential equations is solved numerically for a varying ratio of the energy of anisotropy to the vacuum energy. As the vacuum energy increases, there appears to be less reheating, since the energy of anisotropy is more efficiently converted into isotropic expansion. If the energy of anisotropy is large enough, the inflationary phase is prevented. In this case, a series of cosmological phase transitions will take place each time the square of the effective mass changes its sign.

International Nuclear Information System (INIS)

Pd was deposited onto Si (111) 7x7 surface at approximately 700 K inside an ultrahigh vacuum transmission electron microscope. Plan-viewed transmission electron microscopy (TEM) observation indicated that the islands have two kinds of shapes, round and rectangular (one-dimensional) ones. In a diffraction pattern for the rectangular islands, extra spots along the <110> direction of the Si surface, spacing of which is 1/8 times as long as that of Si (220) spots, were seen. A high resolution TEM image showed the corresponding superstructure in the rectangular islands. In situ observation of the growing process of the rectangular islands showed repeat of introduction and relief of strains during the growth, suggesting that such superstructure would be constructed by stacking compositionally different phases or introducing defects so that the periodically maximized strain is relieved.

CERN Document Server

We review various field theory approaches to the description of neutrino oscillations in vacuum and external fields. First we discuss a relativistic quantum mechanics based approach which involves the temporal evolution of massive neutrinos. To describe the dynamics of the neutrinos system we use exact solutions of wave equations in presence of an external field. It allows one to exactly take into account both the characteristics of neutrinos and the properties of an external field. In particular, we examine flavor oscillations an vacuum and in background matter as well as spin flavor oscillations in matter under the influence of an external electromagnetic field. Moreover we consider the situation of hypothetical nonstandard neutrino interactions with background fermions. In the case of ultrarelativistic particles we reproduce an effective Hamiltonian which is used in the standard quantum mechanical approach for the description of neutrino ...

Science.gov (United States)

Using the infrared spectroscopy method, we have studied the effect of thermal dehydration (under vacuum and in air) and treatment with water vapor on the acid centers of very high silicon zeolites of the ZSM type. We have shown that dehydration under vacuum and in air completely and irreversibly removes the OH groups at 1120/sup 0/K, while treatment with water vapor removes these groups at 770/sup 0/K. The Lewis acid centers of dehydrated zeolites (represented by two types of centers) are more heat-stable than the Bronsted acid centers, but the vapor treatment at 1020/sup 0/K leads to the disappearance of the Lewis acid centers. In this work, we discuss the reasons for destruction of the acid centers of the zeolites under different treatment conditions.

Energy Technology Data Exchange (ETDEWEB)

This paper describes the experimental results of long-life solid lubricated ball bearings tested under high-vacuum of 10 exp -4 Pa, high-temperature of 300 C, and high-speed (9000 rpm) conditions. For full ball-type bearings, the thin soft metals, either Ag or Pb, which were coated on the races and balls, appeared to have good torque properties. However, the durability of such bearings was less than 300 hours. The transfer films from the lamellar solid MoS2 and metal composite retainers improved the torque and wear properties. For ceramic, i.e., silicon nitride, balls used with steel rings, wear occurred on the inner rings. All ceramic bearings with composite retainers showed improved torque and wear properties. 18 refs.

Energy Technology Data Exchange (ETDEWEB)

We investigate the quantum cosmology of spatially homogeneous models with compact spatial sections admitting a u(2) isometry algebra. The metric ansatz in these models is that of Bianchi type IX with two scale factors set to be equal. We apply the Hartle-Hawking no-boundary path integral prescription and find the semi-classical contributions to the wave function. Exact formulae are obtainable for certain contributions and otherwise the limits of large and small anisotropy (for the pure vacuum case) and large spatial volume or small anisotropy (for the case with a positive cosmological constant) are considered. For the pure vacuum case we find no semiclassical components which would correspond to Lorentzian universes. For the case with a cosmological constant the Hartle-Hawking boundary conditions formally constrain one of the parameters in the Lorentzian solutions to be purely imaginary. Possible interpretations of this imaginary parameter are ...

Energy Technology Data Exchange (ETDEWEB)

The growth of the Pd{sub 2}Si thin fllms on Si(111) substrates has been monitored by an {ital in} {ital situ} x-ray diffraction technique in vacuum and in helium atmosphere from 160 to 250 {degree}C. A familiar parabolic growth rate was found, confirming the diffusion-controlled film growth process. The activation energies were found to be 1.34 and 1.37 eV for the measurements performed in vacuum and helium environment, respectively. Stress relaxation in the growing Pd{sub 2}Si fllm was observed when the reaction temperature exceeds 200 {degree}C. The relaxed films showed a higher degree of texture as evidenced by the rocking curve measurements.

Science.gov (United States)

The growth of the Pd{sub 2}Si thin fllms on Si(111) substrates has been monitored by an {ital in} {ital situ} x-ray diffraction technique in vacuum and in helium atmosphere from 160 to 250 {degree}C. A familiar parabolic growth rate was found, confirming the diffusion-controlled film growth process. The activation energies were found to be 1.34 and 1.37 eV for the measurements performed in vacuum and helium environment, respectively. Stress relaxation in the growing Pd{sub 2}Si fllm was observed when the reaction temperature exceeds 200 {degree}C. The relaxed films showed a higher degree of texture as evidenced by the rocking curve measurements.

Energy Technology Data Exchange (ETDEWEB)

The authors investigate the feasibility of constructing walls and partitions with enhanced heat storage capability from cement blocks permeated with an organic phase change material (pressed stearic acid). The blocks are lightweight, easy to produce and are cured in the same way as cement or concrete. The ratio of components (cement, stearic acid (SA) and water) was optimized with respect to compressive strength. With normal portland cement, the best compressive strength 2.2 MPa was obtained with a ratio C:SA:W of 1:0.8:0.65 (i.e. 32% stearic acid) after 28 days of curing. This was increased to 4.4 MPa when high early strength cement was used, about as strong as Sipporex, lightweight concrete or lightweight clay bricks. As expected, the compressive strength decreased linearly with temperature between 25/sup 0/C and 100/sup 0/C, at a rate of 15 kPa//sup 0/C. The drying shrinkage of the modules was found to be 50% greater ...

Science.gov (United States)

The ability to mechanically reinforce an osteoporotic vertebral body could impede spinal compression fracture and the associated pain and complications. Previous studies have shown that reinforcement of fractured vertebrae with conventional acrylic cement can relieve symptoms and avoid further collapse. In this study, we explored the use of a carbonated apatite cement combined with a minimally invasive injection technique to improve the compressive mechanical properties of cadaveric vertebral bodies. After establishing the biomechanical characteristics of cement formulations intended to have appropriate viscosities, we evaluated the infiltration of the cements into thoracic vertebral bodies using a combined suction-injection technique. The energy-absorption capabilities of the reinforced vertebral bodies were then measured during axial compressive tests and compared with those of nonreinforced vertebrae. The ultimate ...

Energy Technology Data Exchange (ETDEWEB)

Uniaxial low-cycle fatigue and creep-fatigue tests have been carried out on hollow alloy 800 specimens that were filled with steam. Two testing temperatures were employed, each with its own steam condition. These temperatures and steam conditions were 650/sup 0/F with saturated steam (5% liquid, 95% vapor) and 1200/sup 0/F with superheated steam at 2200 psi. The low-cycle fatigue tests were carried out at both 650/sup 0/F and 1200/sup 0/F by cycling the strain between equal tensile and compressive magnitudes until specimen failure or until it was no longer practical to continue the test. The creep-fatigue tests were carried out to failure by cycling the strain in the same fashion as in the low-cycle fatigue tests but with holds imposed at either the peak tensile strain or the peak compressive strain or at both peak tensile and compressive strains in each loading cycle.

Science.gov (United States)

The ultimate compressive strength and modulus of elasticity of femoral cortical bone from adult geese (Anser anser), were determined by sex and by quadrant by compressing small right circular cylinders which were 2.4 mm in height and 0.8 mm in diameter. The average ultimate compressive strength was 183 +/- 29 MPa. The average modulus of elasticity was 13.2 +/- 3.4 GPa. The bending strength and bending modulus of elasticity were determined by a three point bend test on rectangular prisms which had the approximate dimensions 0.75 mm X 0.75 mm X 25 mm. The average bending strength was 263 +/- 44 MPa while the average bending modulus was 19.6 +/- 3.1 GPa. The calcium content was determined by atomic absorption spectrophotometry and no correlation was found with the mechanical properties. The histology of the cortical bone was examined both quantitatively and qualitatively. A unique type of Haversian bone is described. Goose ...

International Nuclear Information System (INIS)

The present work focuses on the transformation of high-purity Ni powder blends of controlled volume fractions (40 and 60 %) of nanometre-sized (100 nm) and micrometre-sized (544 nm) particles into bulk samples as part of a strategy for producing ultrafine-grained materials usefully exhibiting both strength and ductility. The process involved cold isostatic pressing at 1.5 GPa and sintering. The resulting bulk samples had relative densities near 95 %, were texture-free, and exhibited two different grain size distributions with an average value of 600 #+-# 30 nm. The mechanical properties were investigated by compression and microhardness tests, both at room temperature, and compared to the behaviour of a sample processed from micrometre-sized powder only. Samples prepared from the blends exhibited high yield stresses of 440 and 550 MPa after compression, and they did sustain work hardening. Tests conducted before and after ...

CERN Document Server

Future High Energy Physics experiments will produce unprecedented data volumes (up to 1 GB/s [1]). In most cases it will be impossible to analyse these data in real time and they will have to be stored on durable mostly magnetic linear media (e.g. tapes) for later analysis. This threatens to become a major cost factor for the running of these experiments. Here we present some ideas developed together with the Institute of Computer Graphics, Department for Algorithms and Programming on how this volume and the related cost can be reduced significantly. The algorithms presented are not general ones but aimed in particular to physics experiments data. Taking advantage of the knowledge of the data they are highly superior to general ones (Huffman, LZW, arithmetic coding) both in compression rate but more importantly in speed as to keep up with the output rate to modern tape drives. Above standard algorithms are, however, used after the data have been transferred in a ...

CERN Document Server

Counting is among the most fundamental operations in computing. For example, counting the pth frequency moment has been a very active area of research, in theoretical computer science, databases, and data mining. When p=1, the task (i.e., counting the sum) can be accomplished using a simple counter. Compressed Counting (CC) is proposed for efficiently computing the pth frequency moment of a data stream signal A_t, where 0= 0, which includes the strict Turnstile model as a special case. For natural data streams encountered in practice, this restriction is minor. The underly technique for CC is what we call skewed stable random projections, which captures the intuition that, when p=1 a simple counter suffices, and when p = 1+/\\Delta with small \\Delta, the sample complexity of a counter system should be low (continuously as a function of \\Delta). We show at small \\Delta the sample complexity (number of projections) k = O(1/\\epsilon) instead of O(1/\\epsilon^2). ...

Science.gov (United States)

A method of producing blast furnace coke from bituminous coals, particularly coals having poor coking capacities in which the coal to be carbonized is ground, predried or preheated, mixed with binders, compressed or formed into briquets having small mechanical resistances and charged into oven chambers, is characterized by fine coals or fine coal mixtures having a swelling index in mixture according to DIN 51741, smaller than 7, and preferably, below 6, and comprising more than 50% of poorly or non-baking coal having a content of volatile matter in excess of 30% or less than 20% which coals or coal mixtures are ground up to attain a surface per unit mass, according to DIN 66145, of from 400 cm/sup 2/ to 1200 cm/sup 2/ per gram, with from 3% to 8% by weight of organic binders, compressing the mixture to form it into a briquet at a temperature range of from 70/sup 0/C to 300/sup 0/C and charging the compressed briquet into ...

Science.gov (United States)

A control group of geese (Anser anser) on a normal calcium diet for egg laying poultry was compared to egg laying geese on a calcium deficient diet. The ultimate compressive strength and modulus of elasticity of femoral cortical bone from each group were determined by compressing right circular cylinders which were 2.4 mm in height and 0.8 mm in diameter. The bending strength and bending modulus of elasticity of tibial cortical bone were determined by three point bend tests on rectangular prisms which were approximately 25 mm by 0.8 mm by 0.8 mm. Bone calcium content and eggshell calcium content were determined by atomic absorption spectrophotometry. Blood samples were analyzed for free calcium ion concentration. Histological observations included studies of cross-sectional microradiographs, examinations of cross sections stained by a modified Masson's technique, and a determination of fractional area of voids by quantitative microscopy. The ...

International Nuclear Information System (INIS)

The refrigerant two-phase flows in a capillary tube and a distributor used in a compression-type refrigerator were visualized by real-time neutron radiography. The thermal neutron radiography system of JRR-3M at the Japan Atomic Energy Research Institute was used. In the visualization experiments of the two-phase flow in the capillary tube of 2 mm I.D., a cooled CCD camera was used, and the axial one-dimensional distributions of void fraction were measured. For the distributor, a high sensitivity video camera with a silicone intensified target tube was used. From the visualized images, the refrigerant behaviors in the distributor were clearly shown, and the liquid fraction in each tube was measured. As a result, it was shown that the refrigerant behaviors in the distributor effected the distributing performance of the refrigerant flow.

International Nuclear Information System (INIS)

Hydrostatic weighing was used to measure the pre-melt density of crystalline eutectic mixtures of alkaline metal chlorides of the compositions (mole fractions): 0.605 LiCl + 0.395 CsCl, 0.585 LiCl + 0.415 KCl, 0.297 NaCl + 0.246 KCl + 0.457 CsCl, and 0.348 NaCl + 0.652 CsCl with melting points 598, 628, 753, 763 K, respectively, as a function of temperature. In the same temperature ranges, the compressibility and molar volume of eutectics as well as their sudden change upon melting were estimated. Unusual variations of these properties were revealed near the crystal/liquid phase transition, which were related to local disordering of particle configuration

British Library Electronic Table of Contents (United Kingdom)

The ever increasing fossil fuel usage and cost, environmental concern has forced the world to look for alternatives. Straight vegetable oils in compression ignition engine are a ready solution available, however, with certain limitations and with some advantages as reported by many researchers. A comprehensive and critical review is presented specifically pertaining to straight vegetable oils usage in diesel engine. A detailed record of historical events described. Research carried out specifically under Indian conditions and international research work on the usage of straight vegetable oils in the diesel engine is separately reviewed. Many researchers have reported that straight vegetable oils in small percentage blends with diesel when used lower capacity diesel engines have shown great...

British Library Electronic Table of Contents (United Kingdom)

Noninvasive prediction of vertebral body strength under compressive loading condition is a valuable tool for the assessment of clinical fractures. This paper presents an effective specimen-specific approach for noninvasive prediction of human vertebral strength using a nonlinear finite element (FE) model and an image based parameter based on the quantitative computed tomography (QCT). Nine thoracolumbar vertebrae excised from three cadavers with an average age of 42 years old were used as the samples. The samples were scanned using the QCT. Then, a segmentation technique was performed on each QCT sectional image. The segmented images were then converted into three-dimensional FE models for linear and nonlinear analyses. A new material model was implemented in our nonlinear model being more...

Energy Technology Data Exchange (ETDEWEB)

The development of a twinned microstructure in hexagonal close-packed rolled magnesium compressed in the in-plane direction has been monitored in situ with neutron diffraction. The continuous conversion of the parent to daughter microstructure is tracked through the variation of diffraction peak intensities corresponding to each. Approximately 80% of the parent microstructure twins by 8% compression. Elastic lattice strain measurements indicate that the stress in the newly formed twins (daughters) is relaxed relative to the stress field in the surrounding matrix. However, since the daughters are in a plastically 'hard' deformation orientation, they quickly accumulate elastic strain as surrounding grains deform plastically. Polycrystal modeling of the deformation process provides insight about the crystallographic deformation mechanism involved.

Energy Technology Data Exchange (ETDEWEB)

The evolution of strain in the Pd-Si system during the growth of Pd{sub 2}Si thin films on Si (100) substrate has been followed in situ using a double optical beam technique. As was observed for the Pt-Si system, the reaction to form Pd{sub 2}Si yields a compressive intrinsic surface film stress as well as for the silicon-rich suicides as proposed by Angilello et al. [Thin Film Interfaces and Interactions, edited by J. Baglin and J. Poate (The Electrochemical Society, Pennington, NJ, 1980)]. A transmission electron microscopy analysis has revealed grain growth during the formation of Pd{sub 2}Si which cannot account for the compressive film stresses. The formation of silicide at the interfaces rather than the overall change in volume agrees with the sign of the stresses formed. 29 refs., 4 figs., 3 tabs.

Energy Technology Data Exchange (ETDEWEB)

A variable-compression ratio, direct-injection diesel engine (VCR) has been designed and assembled at Southwest Research Institute with the intention of examining the current procedures for rating the ignition quality of diesel fuels and the meaning of ignition delay as an indicator of ignition and combustion quality. Using a slightly modified ASTM D 613 procedure, the engine has been used to rate the ignition quality of 43 different test fuels. The ratings obtained in the VCR engine are compared to the corresponding rating obtained using the standard cetane rating procedure. Some of the problems associated with the standard procedure became apparent during these experiments. The experimental results are discussed in terms of the problems and the advantages of a proposed VCR-based rating procedure.

Energy Technology Data Exchange (ETDEWEB)

We present the recent results of our research on the high power ultra-fast silicon RF switches. This switch is composed of a group of PIN diodes on a high purity silicon wafer. The wafer is inserted into a cylindrical waveguide under TE{sub 01} mode, performing switching by injecting carriers into the bulk silicon. Our current design uses a CMOS compatible process and the device was fabricated at SNF (Stanford Nanofabrication Facility). 300 ns switching time has been observed, while the switching speed can be improved further with 3-D device structure and faster driving circuit. Power handling capacity of the switch is at the level of 10 MW. The switch was designed for active X-band RF pulse compression systems--especially for NLC, but it is also possible to be modified for other applications and other frequencies.

Energy Technology Data Exchange (ETDEWEB)

Flywheels containing fiber-reinforced composite materials have attributes suitable for vehicular propulsion, indicating the need for rotor designs which are easily manufactured and low in cost. This development goal was pursued in a cooperative effort between Owens-Corning Fiberglas and Lawrence Livermore Laboratory which investigated flywheels made from compression-molded sheet molding compound (SMC). The design resulted from a Lawrence Livermore analysis, with successful fabrication achieved using a procedure developed by Owens-Corning. Details concerning materials selection, rotor fabrication, and testing are discussed. Owens-Corning subsequently initiated a technical/marketing survey to determine current industrial interests in a low-cost flywheel design; precursory information, pertaining to composite flywheels in particular, is described.

Energy Technology Data Exchange (ETDEWEB)

An experimental investigation has been carried out to examine for the first time the performance and combustion noise of an indirect injection diesel engine running with new fuel derived from pure jojoba oil, jojoba methyl ester, and its blends with gas oil. A Ricardo E6 compression swirl diesel engine was fully instrumented for the measurement of combustion pressure and its rise rate and other operating parameters. Test parameters included the percentage of jojoba methyl ester in the blend, engine speed, load, injection timing and engine compression ratio. Results showed that the new fuel derived from jojoba is generally comparable and a good replacement to gas oil in diesel engine at most engine operating conditions, in terms of performance parameters and combustion noise produced. (author)

Energy Technology Data Exchange (ETDEWEB)

The authors calculate the effective potential for the bosonic sector of eleven-dimensional supergravity on the background (Minkowski) x (sphere). No tachyons are found, and it is shown that the antisymmetric tensor field does not threaten graviton dominance when the Freund-Rubin parameter (m) vanishes. The general case (m not = O) seems untractable in the present formalism.

Energy Technology Data Exchange (ETDEWEB)

A Bianchi type-IX cosmological model has been found as a solution of Einstien's vacuum field equations with a cosmological constant. The solution represents a rotating generalziation fo the de Sitter universe. This universe shows a transition to exponential expansion and the vorticity begins to decay exponentially at the grand-unified-theory time. The point of time for this transition is independent of the magnitude of the vorticity. During the Guth inflationary era the vorticity decays by a factor of the order 10 US.

International Nuclear Information System (INIS)

This paper extends the development of a new formulation of the theory of tachyons to encompass the dynamics of tachyons. Energy and momentum are discussed along with the proper mass of a tachyon. The transformation of force in extended relativity (ER) is derived. Acceleration in ER is also discussed, as well as the relationship between force and acceleration. Two simple examples relating to the motion of a charged tachyon are discussed, followed by a brief explanation of why tachyons cannot emit Cerenkov radiation in a vacuum. 13 refs., 3 figs.

Energy Technology Data Exchange (ETDEWEB)

The motion of an accelerated charge in a vacuum is analyzed, via the superposition principle and Fourier analysis, into uniform-motion components, which include bradyonic as well as tachyonic contributions. It is shown that the former contribute only to the induction fields whereas the latter are the source of the radiation emitted by the charge, via the Sommerfeld-Cerenkov mechanism. This result calls for a reexamination of some recently formulated theories of superluminal particles.

Energy Technology Data Exchange (ETDEWEB)

A Monte Carlo simulation of the vacuum Bianchi type-IX (mixmaster) cosmology yields a significant correlation between large universe volume and high anisotropy. An analog of the model's chaotic classical behavior is seen in the break up of the universe wave function at large volume into fingers in the corners of the minisuperspace anisotropy potential.