Quantum transfer energy in the framework of time-dependent dipole-dipole interaction

Science.gov (United States)

El-Shishtawy, Reda M.; Haddon, Robert C.; Al-Heniti, Saleh H.; Raffah, Bahaaudin M.; Berrada, K.; Abdel-Khalek, S.; Al-Hadeethi, Yas F.

2018-03-01

In this work, we examine the process of the quantum transfer of energy considering time-dependent dipole-dipole interaction in a dimer system characterized by two-level atom systems. By taking into account the effect of the acceleration and speed of the atoms in the dimer coupling, we demonstrate that the improvement of the probability for a single-excitation transfer energy extremely benefits from the incorporation of atomic motion effectiveness and the energy detuning. We explore the relevance between the population and entanglement during the time-evolution and show that this kind of nonlocal correlation may be generated during the process of the transfer of energy. Our work may provide optimal conditions to implement realistic experimental scenario in the transfer of the quantum energy.

Energy decay of a variable-coefficient wave equation with nonlinear time-dependent localized damping

Directory of Open Access Journals (Sweden)

Jieqiong Wu

2015-09-01

Full Text Available We study the energy decay for the Cauchy problem of the wave equation with nonlinear time-dependent and space-dependent damping. The damping is localized in a bounded domain and near infinity, and the principal part of the wave equation has a variable-coefficient. We apply the multiplier method for variable-coefficient equations, and obtain an energy decay that depends on the property of the coefficient of the damping term.

Energy deposition and the formation of biologically significant lesions by accelerated ions

International Nuclear Information System (INIS)

Kiefer, J.

1985-01-01

The assumption that the number of biologically significant lesions depends only on the amount of of energy absorbed in a critical cellular site is not able to explain the increase of RBE with LET and leads to large discrepancies between predicted and measured inactivation cross sections in the LET range between 20 and 200 keV.μm -1 . It has, therefore, to be concluded that not only the amount of energy absorbed but also the spatial pattern of this deposition plays a decisive role. In the model presented it is postulated that two or more energy deposition events in nanometre sites are required for the formation of biologically significant lesions. This cooperative action has to take place in very short times so that only interactions within a single particle track contribute. The mathematical treatment will be outlined and qualitatively shown that the model is able to predict RBE-LET relationships. The calculations use a track structure model based on classical collision mechanics. It is compared with existing experimental results showing good agreement at least for higher particle energies. (author)

Influence of deposition time on the properties of chemical bath deposited manganese sulfide thin films

Directory of Open Access Journals (Sweden)

Anuar Kassim

2010-12-01

Full Text Available Manganese sulfide thin films were chemically deposited from an aqueous solution containing manganese sulfate, sodium thiosulfate and sodium tartrate. The influence of deposition time (2, 3, 6 and 8 days on the properties of thin films was investigated. The structure and surface morphology of the thin films were studied by X-ray diffraction and atomic force microscopy, respectively. In addition, in order to investigate the optical properties of the thin films, the UV-visible spectrophotometry was used. The XRD results indicated that the deposited MnS2 thin films exhibited a polycrystalline cubic structure. The number of MnS2 peaks on the XRD patterns initially increased from three to six peaks and then decreased to five peaks, as the deposition time was increased from 2 to 8 days. From the AFM measurements, the film thickness and surface roughness were found to be dependent on the deposition time.

Evaluation of energy deposition by 153Sm in small samples

International Nuclear Information System (INIS)

Cury, M.I.C.; Siqueira, P.T.D.; Yoriyaz, H.; Coelho, P.R.P.; Da Silva, M.A.; Okazaki, K.

2002-01-01

Aim: This work presents evaluations of the absorbed dose by 'in vitro' blood cultures when mixed with 153 Sm solutions of different concentrations. Although 153 Sm is used as radiopharmaceutical mainly due to its beta emission, which is short-range radiation, it also emits gamma radiation which has a longer-range penetration. Therefore it turns to be a difficult task to determine the absorbed dose by small samples where the infinite approximation is no longer valid. Materials and Methods: MCNP-4C (Monte Carlo N - Particle transport code) has been used to perform the evaluations. It is not a deterministic code that calculates the value of a specific quantity solving the physical equations involved in the problem, but a virtual experiment where the events related to the problems are simulated and the concerned quantities are tallied. MCNP also stands out by its possibilities to specify geometrically any problem. However, these features, among others, turns MCNP in a time consuming code. The simulated problem consists of a cylindrical plastic tube with 1.5 cm internal diameter and 0.1cm thickness. It also has 2.0 cm height conic bottom end, so that the represented sample has 4.0 ml ( consisted by 1 ml of blood and 3 ml culture medium). To evaluate the energy deposition in the blood culture in each 153 Sm decay, the problem has been divided in 3 steps to account to the β- emissions (which has a continuum spectrum), gammas and conversion and Auger electrons emissions. Afterwards each emission contribution was weighted and summed to present the final value. Besides this radiation 'fragmentation', simulations were performed for many different amounts of 153 Sm solution added to the sample. These amounts cover a range from 1μl to 0.5 ml. Results: The average energy per disintegration of 153 Sm is 331 keV [1]. Gammas account for 63 keV and β-, conversion and Auger electrons account for 268 keV. The simulations performed showed an average energy deposition of 260 ke

Influence of emitter temperature on the energy deposition in a low-pressure plasma

International Nuclear Information System (INIS)

Levko, Dmitry; Raja, Laxminarayan L.

2016-01-01

The influence of emitter temperature on the energy deposition into low-pressure plasma is studied by the self-consistent one-dimensional Particle-in-Cell Monte Carlo Collisions model. Depending on the emitter temperature, different modes of discharge operation are obtained. The mode type depends on the plasma frequency and does not depend on the ratio between the densities of beam and plasma electrons. Namely, plasma is stable when the plasma frequency is small. For this plasma, the energy transfer from emitted electrons to plasma electrons is inefficient. The increase in the plasma frequency results first in the excitation of two-stream electron instability. However, since the thermal velocity of plasma electrons is smaller than the electrostatic wave velocity, the resonant wave-particle interaction is inefficient for the energy deposition into the plasma. Further increase in the plasma frequency leads to the distortion of beam of emitted electrons. Then, the electrostatic wave generated due to two-stream instability decays into multiple slower waves. Phase velocities of these waves are comparable with the thermal velocity of plasma electrons which makes possible the resonant wave-particle interaction. This results in the efficient energy deposition from emitted electrons into the plasma.

Energy deposition, heat flow, and rapid solidification during laser and electron beam irradiation of materials

Energy Technology Data Exchange (ETDEWEB)

White, C.W.; Aziz, M.J.

1985-10-01

The fundamentals of energy deposition, heat flow, and rapid solidification during energy deposition from lasers and electron beams is reviewed. Emphasis is placed on the deposition of energy from pulsed sources (10 to 100 ns pulse duration time) in order to achieve high heating and cooling rates (10/sup 8/ to 10/sup 10/ /sup 0/C/s) in the near surface region. The response of both metals and semiconductors to pulsed energy deposition is considered. Guidelines are presented for the choice of energy source, wavelength, and pulse duration time.

Measurements of time dependent energy spectra of neutrons in a small graphite assembly

International Nuclear Information System (INIS)

Fujita, Yoshiaki; Sakamoto, Shigeyasu; Aizawa, Otohiko; Takahashi, Akito; Sumita, Kenji.

1975-01-01

The time-dependent energy spectra of neutrons have been measured in a small 30x30x30 cm 3 graphite assembly by means of the linac-chopper method, with a view to establishing experimental evidence that there is no asymptotic spectrum in such a small assembly, and in order to study the non-asymptotic behavior of neutrons. The arrangement of a polyethylene pre-moderator adjacent to the assembly made the measurements possible with the improvement obtained thereby of the neutron counting statistics. It was indicated from calculation that the presence of the pre-moderator had little effect - at least above the Bragg cut-off energy - on the evolution in time of the energy spectra of neutrons in the graphite assembly. The experimental results indicated very probable disappearance of asymptotic spectra, and revealed significant enhancement of trapping at Bragg energies with the lapse of time. This is consistent with the results of pulsed neutron experiments in small assemblies conducted by Takahashi et al., and falls in line with de Saussure's approximation. The spectra in the graphite assembly showed significant space dependence, the spectra becoming harder with increasing distance from the pre-moderator. This hardening may be attributed to the relatively faster propagation of higher energy neutrons. (auth.)

Dry deposition to vegetated surfaces: parametric dependencies

International Nuclear Information System (INIS)

Underwood, B.Y.

1987-12-01

The dry deposition velocity of airborne pollutants to vegetated surfaces depends on the physico-chemical form of the pollutant, on meteorological conditions (windspeed, atmospheric stability) and on characteristics of the surface cover. This report examines these dependencies, drawing on experimental data and on information from theoretical analyses. A canopy model is outlined which uses first-order closure of the equations for turbulent transport of momentum (or matter), with losses of momentum (or matter) to individual canopy elements parameterised in terms of the mean windspeed: the model has previously been tested against experimental data on an artificial 'grass' canopy. The model is used to elucidate the features of the dependence of deposition velocity on windspeed and on whether the pollutant is in gaseous or particulate form: in the former case, the dependence on the molecular diffusivity of the gas is shown; in the latter case, dependencies on particle diameter and density are deduced. The predictions are related to available measurements. Additional hypotheses are introduced to treat the influence of atmospheric stability on deposition, and the analysis is used to shed light on the somewhat confusing picture that has emerged from past experimental studies. In considering the dependence of deposition velocity on the structural properties of the vegetation, it is established that more parameters than the single one conventionally used -aerodynamic roughness length - are needed to characterise the surface cover. Some indications of the extent of variation in deposition velocity from one type of vegetation to another are elicited from the model. (author)

Study of energy deposition in heavy-ion reactions

International Nuclear Information System (INIS)

Mota, V. De La; Abgrall, P.; Sebille, F.; Haddad, F.

1993-01-01

An investigation of energy deposition mechanisms in heavy-ion reactions at intermediate energies is presented. Theoretical simulations are performed in the framework of the semi-classical Landau-Vlasov model. They emphasize the influence of the initial non-equilibrium conditions, and the connection with the incident energy is discussed. Characteristic times involved in the energy thermalization process and finite size effects are analyzed. (authors) 20 refs., 4 figs

Simulating time-dependent energy transfer between crossed laser beams in an expanding plasma

International Nuclear Information System (INIS)

Hittinger, J.A.F.; Dorr, M.R.; Berger, R.L.; Williams, E.A.

2005-01-01

A coupled mode system is derived to investigate a three-wave parametric instability leading to energy transfer between co-propagating laser beams crossing in a plasma flow. The model includes beams of finite width refracting in a prescribed transverse plasma flow with spatial and temporal gradients in velocity and density. The resulting paraxial light equations are discretized spatially with a Crank-Nicholson-type scheme, and these algebraic constraints are nonlinearly coupled with ordinary differential equations in time that describe the ion acoustic response. The entire nonlinear differential-algebraic system is solved using an adaptive, backward-differencing method coupled with Newton's method. A numerical study is conducted in two dimensions that compares the intensity gain of the fully time-dependent coupled mode system with the gain computed under the further assumption of a strongly damped ion acoustic response. The results demonstrate a time-dependent gain suppression when the beam diameter is commensurate with the velocity gradient scale length. The gain suppression is shown to depend on time-dependent beam refraction and is interpreted as a time-dependent frequency shift

Structural and Optical Properties of Chemical Bath Deposited Silver Oxide Thin Films: Role of Deposition Time

Directory of Open Access Journals (Sweden)

A. C. Nwanya

2013-01-01

Full Text Available Silver oxide thin films were deposited on glass substrates at a temperature of 50°C by chemical bath deposition technique under different deposition times using pure AgNO3 precursor and triethanolamine as the complexing agent. The chemical analysis based on EDX technique shows the presence of Ag and O at the appropriate energy levels. The morphological features obtained from SEM showed that the AgxO structures varied as the deposition time changes. The X-ray diffraction showed the peaks of Ag2O and AgO in the structure. The direct band gap and the refractive index increased as the deposition time increased and was in the range of 1.64–1.95 eV and 1.02–2.07, respectively. The values of the band gap and refractive index obtained indicate possible applications in photovoltaic and photothermal systems.

Analysis of cavity effect on space- and time-dependent fast and thermal neutron energy spectra

International Nuclear Information System (INIS)

Kudo, Katsuhisa; Narita, Masakuni; Ozawa, Yasutomo.

1975-01-01

The effects of the presence of a central cavity on the space- and time-dependent neutron energy spectra in both thermal and fast neutron systems are analyzed theoretically with use made of the multi-group one-dimensional time-dependent Ssub(n) method. The thermal neutron field is also analyzed for the case of a fundamental time eigenvalue problem with the time-dependent P 1 approximation. The cavity radius is variable, and the system radius for graphite is 120 cm and for the other materials 7 cm. From the analysis of the time-dependent Ssub(n) calculations in the non-multiplying systems of polythene, light water and graphite, cavity heating is the dominant effect for the slowing-down spectrum in the initial period following fast neutron burst, and when the slowing-down spectrum comes into the thermal energy region, cavity heating shifts to cavity cooling. In the multiplying system of 235 U, cavity cooling also takes place as the spectrum approaches equilibrium after the fast neutron burst is injected. The mechanism of cavity cooling is explained analytically for the case of thermal neutron field to illustrate its physical aspects, using the time-dependent P 1 approximation. An example is given for the case of light water. (auth.)

Time-fractional particle deposition in porous media

Science.gov (United States)

Xu, Jianping

2017-05-01

In the percolation process where fluids carry small solid particles, particle deposition causes a real-time permeability change of the medium as the swarm of particles propagates along the medium. Then the permeability change influences percolation and deposition behaviors as a feedback. This fact triggers memory effect in the deposition dynamics, which means the particulate transport and deposition behaviors become history-dependent. In this paper, we conduct the time-fractional generalization of the classical phenomenological model of particle deposition in porous media to incorporate the memory effect. We tested and compared the effects of employing different types of fractional operators, i.e. the Riemann-Liouville type, the Hadamard type and the Prabhakar type. Numerical simulation results show that the system behaviors vary according to the change of distinct memory kernels in an expected way. We then discuss the physical meaning of the time-fractional generalization. It is shown that different types of fractional operators unanimously ground themselves on the local-Newtonian time transformation in a complex system, which is equivalent to a class of history integrals. By the introduction of various memory kernels, it enables the model to more powerfully fit and approximate observed data. Further, the fundamental meaning of this work is not to show which fractional operator is ‘better’, but to argue collectively the legitimacy and practicality of a non-Markovian particle deposition dynamics in porous media, and in fact it is admissible to a bunch of memory kernels which differ greatly from each other in functional forms. Hopefully the presented generalized mass conservation formalism offers a broader framework to investigate transport problems in porous media.

Time-fractional particle deposition in porous media

International Nuclear Information System (INIS)

Xu, Jianping

2017-01-01

In the percolation process where fluids carry small solid particles, particle deposition causes a real-time permeability change of the medium as the swarm of particles propagates along the medium. Then the permeability change influences percolation and deposition behaviors as a feedback. This fact triggers memory effect in the deposition dynamics, which means the particulate transport and deposition behaviors become history-dependent. In this paper, we conduct the time-fractional generalization of the classical phenomenological model of particle deposition in porous media to incorporate the memory effect. We tested and compared the effects of employing different types of fractional operators, i.e. the Riemann–Liouville type, the Hadamard type and the Prabhakar type. Numerical simulation results show that the system behaviors vary according to the change of distinct memory kernels in an expected way. We then discuss the physical meaning of the time-fractional generalization. It is shown that different types of fractional operators unanimously ground themselves on the local-Newtonian time transformation in a complex system, which is equivalent to a class of history integrals. By the introduction of various memory kernels, it enables the model to more powerfully fit and approximate observed data. Further, the fundamental meaning of this work is not to show which fractional operator is ‘better’, but to argue collectively the legitimacy and practicality of a non-Markovian particle deposition dynamics in porous media, and in fact it is admissible to a bunch of memory kernels which differ greatly from each other in functional forms. Hopefully the presented generalized mass conservation formalism offers a broader framework to investigate transport problems in porous media. (paper)

COREL, Ion Implantation in Solids, Range, Straggling Using Thomas-Fermi Cross-Sections. RASE4, Ion Implantation in Solids, Range, Straggling, Energy Deposition, Recoils. DAMG2, Ion Implantation in Solids, Energy Deposition Distribution with Recoils

International Nuclear Information System (INIS)

Brice, D. K.

1979-01-01

coefficients in the equation, the energy deposition rates, and the recoil range and straggling variables are obtained by rectangular integration over the Thomas-Fermi elastic scattering cross section. DAMG2: The integral which governs the depth distribution of interest is evaluated by rectangular integration. Energy redistribution by the recoiling target atoms is included in a Gaussian approximation. 3 - Restrictions on the complexity of the problem: COREL and RASE4: Compound targets with up to four different atomic constituents may be considered. The maximum incident energy which may be used is 800 times the Lindhard characteristic energy, a quantity which depends on the mass and atomic number of the incident projectile and the target atoms. Maximum incident energy can be increased by increasing storage area available for the program, and increasing the dimensions of the energy-dependent arrays

Energy shift and conduction-to-valence band transition mediated by a time-dependent potential barrier in graphene

Science.gov (United States)

Chaves, Andrey; da Costa, D. R.; de Sousa, G. O.; Pereira, J. M.; Farias, G. A.

2015-09-01

We investigate the scattering of a wave packet describing low-energy electrons in graphene by a time-dependent finite-step potential barrier. Our results demonstrate that, after Klein tunneling through the barrier, the electron acquires an extra energy which depends on the rate of change of the barrier height with time. If this rate is negative, the electron loses energy and ends up as a valence band state after leaving the barrier, which effectively behaves as a positively charged quasiparticle.

Universal time-dependence of the mean-square displacement in extremely rugged energy landscapes with equal minima

DEFF Research Database (Denmark)

Dyre, Jeppe; Jacobsen, Jacob M.

1995-01-01

This paper presents a calculation of the time dependence of the mean-square displacement for symmetric random energy barrier hopping models at low temperatures, where the frequency dependence of the normalized diffusion constant D-tilde becomes universal, i.e., independent of the energy barrier...... probability distribution [J. C. Dyre, Phys. Rev. B 49, 11 709 (1994)]. The universal time dependence of the mean-square displacement is calculated from the effective medium approximation (EMA) universality equation, D-tilde lnD-tilde=s-tilde, where s-tilde is the dimensionless imaginary frequency, as well...... as for the approximation to the EMA universality equation D-tilde~=s-tilde/ln(1+s-tilde). At long times the universal mean-square displacement is linear in time, corresponding to ordinary diffusion, whereas the mean-square displacement at short times t in dimensionless units varies as 2/ln(t-1)....

Effects of Energy Deposition Characteristics on Localised Forced Ignition of Homogeneous Mixtures

Directory of Open Access Journals (Sweden)

Dipal Patel

2015-06-01

Full Text Available The effects of the characteristic width of the energy deposition profile and the duration of energy deposition by the ignitor on localised forced ignition of stoichiometric and fuel-lean homogeneous mixtures have been analysed using simplified chemistry three-dimensional compressible Direct Numerical Simulation (DNS for different values of root-mean-square turbulent velocity fluctuation. The localised forced ignition is modelled using a source term in the energy transport equation, which deposits energy in a Gaussian manner from the centre of the ignitor over a stipulated period of time. It has been shown that the width of ignition energy deposition and the duration over which ignition energy is deposited have significant influences on the success of ignition and subsequent flame propagation. An increase in the width of ignition energy deposition (duration of energy deposition for a given amount of ignition energy has been found to have a detrimental effect on the ignition event, which may ultimately lead to misfire. Moreover, an increase in u′ gives rise to augmented heat transfer rate from the hot gas kernel, which in turn leads to a reduction in the extent of overall burning for both stoichiometric and fuel-lean homogeneous mixtures but the detrimental effects of high values of u′ on localised ignition are particularly prevalent for fuel-lean mixtures.

Measurement of time-dependent fast neutron energy spectra in a depleted uranium assembly

International Nuclear Information System (INIS)

Whittlestone, S.

1980-10-01

Time-dependent neutron energy spectra in the range 0.6 to 6.4 MeV have been measured in a depleted uranium assembly. By selecting windows in the time range 0.9 to 82 ns after the beam pulse, it was possible to observe the change of the neutron energy distributions from spectra of predominantly 4 to 6 MeV neutrons to spectra composed almost entirely of fission neutrons. The measured spectra were compared to a Monte Carlo calculation of the experiment using the ENDF/B-IV data file. At times and energies at which the calculation predicted a fission spectrum, the experiment agreed with the calculation, confirming the accuracy of the neutron spectroscopy system. However, the presence of discrepancies at other times and energies suggested that there are significant inconsistencies in the inelastic cross sections in the 1 to 6 MeV range. The time response generated concurrently with the energy spectra was compared to the Monte Carlo calculation. From this comparison, and from examination of time spectra measured by other workers using 235 U and 237 Np fission detectors, it would appear that there are discrepancies in the ENDF/B-IV cross sections below 1 MeV. The predicted decay rates were too low below and too high above 0.8 MeV

Abnormal energy deposition on the wall through plasma disruptions

International Nuclear Information System (INIS)

Yamazaki, K.; Schmidt, G.L.

1984-07-01

The dissipation of plasma kinetic and magnetic energy during sawtooth oscillstions and disruptions in tokamaks is analyzed using Kadomtsev's disruption model and the plasma-circuit equations. New simple scalings of several characteristic times are obtained for sawteeth and for thermal and magnetic energy quenches of disruptions. The abnormal energy deposition on the wall during major or minor disruptions, estimated from this analysis, is compared with bolometric measurements in the PDX tokamak. Especially, magnetic energy dissipation during current termination period is shown to be reduced by the strong coupling of the plasma current with external circuits. These analyses are found to be useful to predict the phenomenological behavior of plasma disruptions in large future tokamaks, and to estimate abnormal heat deposition on the wall during plasma disruptions. (author)

Analytic solutions to linear, time-dependent fission product deposition models for isothermal laminar, slug, or multiregion flow conditions

International Nuclear Information System (INIS)

Durkee, J.W. Jr.

1983-01-01

The time-dependent convective-diffusion equation with radioactive decay is solved analytically in axisymmetric cylindrical geometry for laminar and slug velocity profiles under isothermal conditions. Concentration dependent diffusion is neglected. The laminar flow solution is derived using the method of separation of variables and Frobenius' technique for constructing a series expansion about a regular singular point. The slug flow multiregion solution is obtained using the method of separation of variables. The Davidon Variable Metric Minimization algorithm is used to compute the coupling coefficients. These solutions, which describe the transport of fission products in a flowing stream, are then used to determine the concentration of radioactive material deposited on a conduit wall using a standard mass transfer model. Fission product deposition measurements for five diffusion tubes in a Fort St. Vrain High-Temperature Gas-Cooled reactor plateout probe are analyzed. Using single region slug and laminar models, the wall mass transfer coefficients, diffusion coefficients, and inlet concentrations are determined using least squares analysis. The diffusion coefficients and inlet concentrations are consistent between tubes. The derived diffusion coefficients and wall mass transfer coefficients are in relative agreement with known literature values

Global, finite energy, weak solutions for the NLS with rough, time-dependent magnetic potentials

Science.gov (United States)

Antonelli, Paolo; Michelangeli, Alessandro; Scandone, Raffaele

2018-04-01

We prove the existence of weak solutions in the space of energy for a class of nonlinear Schrödinger equations in the presence of a external, rough, time-dependent magnetic potential. Under our assumptions, it is not possible to study the problem by means of usual arguments like resolvent techniques or Fourier integral operators, for example. We use a parabolic regularisation, and we solve the approximating Cauchy problem. This is achieved by obtaining suitable smoothing estimates for the dissipative evolution. The total mass and energy bounds allow to extend the solution globally in time. We then infer sufficient compactness properties in order to produce a global-in-time finite energy weak solution to our original problem.

Halite depositional facies in a solar salt pond: A key to interpreting physical energy and water depth in ancient deposits?

Science.gov (United States)

Robertson Handford, C.

1990-08-01

Subaqueous deposits of aragonite, gypsum, and halite are accumulating in shallow solar salt ponds constructed in the Pekelmeer, a sea-level sauna on Bonaire, Netherlands Antilles. Several halite facies are deposited in the crystallizer ponds in response to differences in water depth and wave energy. Cumulate halite, which originates as floating rafts, is present only along the protected, upwind margins of ponds where low-energy conditions foster their formation and preservation. Cornet crystals with peculiar mushroom- and mortarboard-shaped caps precipitate in centimetre-deep brine sheets within a couple of metres of the upwind or low-energy margins. Downwind from these margins, cornet and chevron halite precipitate on the pond floors in water depths ranging from a few centimetres to ˜60 cm. Halite pisoids with radial-concentric structure are precipitated in the swash zone along downwind high-energy shorelines where they form pebbly beaches. This study suggests that primary halite facies are energy and/or depth dependent and that some primary features, if preserved in ancient halite deposits, can be used to infer physical energy conditions, subenvironments such as low- to high-energy shorelines, and extremely shallow water depths in ancient evaporite basins.

Influence of plasma-induced energy deposition effects, the equation of state, thermal ionization, pulse shaping, and radiation on ion-beam-driven expansions of plane metal targets

International Nuclear Information System (INIS)

Long, K.A.; Tahir, N.A.

1986-01-01

In a previous paper by Long and Tahir [Phys. Fluids 29, 275 (1986)], the motion of plane targets irradiated by ion beams whose energy deposition was assumed to be independent of the ion energy, and the temperature and density of the plasma, was analyzed. In this paper, the analytic solution is extended in order to include the effects of a temperature-and density-dependent energy deposition as a result of electron excitation, an improved equation of state, thermal ionization, a pulse shape, and radiation losses. The change in the energy deposition with temperature and density leads to range shortening and an increased power deposition in the target. It is shown how the analytic theory can be used to analyze experiments to measure the enhanced energy deposition. In order to further analyze experiments, numerical simulations are presented which include the plasma-induced effects on the energy deposition. It is shown that since the change in the range is due to both decrease in density and the increase in temperature, it is not possible to separate these two effects in present experiments. Therefore, the experiments which measure the time-dependent energy of the ions emerging from the back side of a plane target do not as yet measure the energy loss as a function of the density and temperature of the plasma or of the energy of the ion, but only an averaged loss over certain ranges of these physical quantities

Simulation of spatially dependent excitation rates and power deposition in RF discharges for plasma processing

International Nuclear Information System (INIS)

Kushner, M.J.; Anderson, H.M.; Hargis, P.J.

1985-01-01

In low pressure, radio frequency (RF) discharges of the type used in plasma processing of semiconductor materials, the rate of electron impact excitation and energy transfer processes depends upon both the phase of the RF excitation and position in the discharge. Electron impact collisions create radicals that diffuse or drift to the surfaces of interest where they are adsorbed or otherwise react. To the extent that these radicals have a finite lifetime, their transport time from point of creation to surface of interest is an important parameter. The spatial dependence of the rate of the initial electron impact collisions is therefore also an important parameter. The power that sustains the discharge is coupled into the system by two mechanisms: a high energy e-beam component of the electron distribution resulting from electrons falling through or being accelerated by the sheaths, and by joule heating in the body of the plasma. In this paper, the authors discuss the spatial dependence of excitation rates and the method of power deposition iin RF discharges of the type used for plasma processing

Effect of heat treatment on the characteristics of tool steel deposited by the directed energy deposition process

Science.gov (United States)

Park, Jun Seok; Lee, Min-Gyu; Cho, Yong-Jae; Sung, Ji Hyun; Jeong, Myeong-Sik; Lee, Sang-Kon; Choi, Yong-Jin; Kim, Da Hye

2016-01-01

The directed energy deposition process has been mainly applied to re-work and the restoration of damaged steel. Differences in material properties between the base and the newly deposited materials are unavoidable, which may affect the mechanical properties and durability of the part. We investigated the effect of heat treatment on the characteristics of tool steel deposited by the DED process. We prepared general tool steel materials of H13 and D2 that were deposited onto heat-treated substrates of H13 and D2, respectively, using a direct metal tooling process. The hardness and microstructure of the deposited steel before and after heat treatment were investigated. The hardness of the deposited H13 steel was higher than that of wrought H13 steel substrate, while that of the deposited D2 was lower than that of wrought D2. The evolution of the microstructures by deposition and heat treatment varied depending on the materials. In particular, the microstructure of the deposited D2 steel after heat treatment consisted of fine carbides in tempered martensite and it is expected that the deposited D2 steel will have isotropic properties and high hardness after heat treatment.

Abnormal energy deposition on the wall through plasma disruptions

International Nuclear Information System (INIS)

Yamazaki, K.; Schmidt, G.L.

1984-01-01

The dissipation of plasma kinetic and magnetic energy during sawtooth oscillations and disruptions in tokamak is analyzed using Kadomtsev's disruption model and the plasma-circuit equations. New simple scalings of several characteristic times are obtained for sawteeth and for thermal and magnetic energy quenches of disruptions. The abnormal energy deposition on the wall during major or minor disruptions, estimated from this analysis, is compared with bolometric measurements in the PDX tokamak. Especially, magnetic energy dissipation during the current termination period is shown to be reduced by the strong coupling of the plasma current with external circuits. These analyses are found to be useful to predict the phenomenological behavior of plasma disruptions in large future tokamaks, and to estimate abnormal heat deposition on the wall during plasma disruptions. (orig.)

Energy deposition in NSRR test fuels

International Nuclear Information System (INIS)

Ohnishi, Nobuaki; Tanzawa, Sadamitsu; Tanzawa, Tomio; Kitano, Teruaki; Okazaki, Shuji

1978-02-01

Interpretation of fuel performance data collected during inpile testing in the NSRR requires a knowledge of the energy deposition or enthalpy increase in each sample tested. The report describes the results of absolute measurement of fission products and contents of uranium in irradiated test fuels which were performed to determine the energy deposition. (auth.)

Accurate Ground-State Energies of Solids and Molecules from Time-Dependent Density-Functional Theory

DEFF Research Database (Denmark)

Olsen, Thomas; Thygesen, Kristian Sommer

2014-01-01

We demonstrate that ground-state energies approaching chemical accuracy can be obtained by combining the adiabatic-connection fluctuation-dissipation theorem with time-dependent densityfunctional theory. The key ingredient is a renormalization scheme, which eliminates the divergence...

Effect of energy deposited by cosmic-ray particles on interferometric gravitational wave detectors

International Nuclear Information System (INIS)

Yamamoto, Kazuhiro; Hayakawa, Hideaki; Okada, Atsushi; Uchiyama, Takashi; Miyoki, Shinji; Ohashi, Masatake; Kuroda, Kazuaki; Kanda, Nobuyuki; Tatsumi, Daisuke; Tsunesada, Yoshiki

2008-01-01

We investigated the noise of interferometric gravitational wave detectors due to heat energy deposited by cosmic-ray particles. We derived a general formula that describes the response of a mirror against a cosmic-ray passage. We found that there are differences in the comic-ray responses (the dependence of temperature and cosmic-ray track position) in cases of interferometric and resonant gravitational wave detectors. The power spectral density of vibrations caused by low-energy secondary muons is 100 times smaller than the goal sensitivity of future second-generation interferometer projects, such as LCGT and Advanced LIGO. The arrival frequency of high-energy cosmic-ray muons that generate enough large showers inside mirrors of LCGT and Advanced LIGO is one per a millennium. We also discuss the probability of exotic-particle detection with interferometers.

Influence of multi-deposition multi-annealing on time-dependent dielectric breakdown characteristics of PMOS with high-k/metal gate last process

International Nuclear Information System (INIS)

Wang Yan-Rong; Yang Hong; Xu Hao; Wang Xiao-Lei; Luo Wei-Chun; Qi Lu-Wei; Zhang Shu-Xiang; Wang Wen-Wu; Yan Jiang; Zhu Hui-Long; Zhao Chao; Chen Da-Peng; Ye Tian-Chun

2015-01-01

A multi-deposition multi-annealing technique (MDMA) is introduced into the process of high-k/metal gate MOSFET for the gate last process to effectively reduce the gate leakage and improve the device’s performance. In this paper, we systematically investigate the electrical parameters and the time-dependent dielectric breakdown (TDDB) characteristics of positive channel metal oxide semiconductor (PMOS) under different MDMA process conditions, including the deposition/annealing (D and A) cycles, the D and A time, and the total annealing time. The results show that the increases of the number of D and A cycles (from 1 to 2) and D and A time (from 15 s to 30 s) can contribute to the results that the gate leakage current decreases by about one order of magnitude and that the time to fail (TTF) at 63.2% increases by about several times. However, too many D and A cycles (such as 4 cycles) make the equivalent oxide thickness (EOT) increase by about 1 Å and the TTF of PMOS worsen. Moreover, different D and A times and numbers of D and A cycles induce different breakdown mechanisms. (paper)

Experiment study on the thick GEM-like multiplier for X-ray photoelectrons energy deposition gaining

International Nuclear Information System (INIS)

Zhu Pengfei; Ye Yan; Long Yan; Cao Ningxiang; Jia Xing; Li Jianfeng

2009-01-01

The GEM is a novel detector with high gain,high time and location resolution. Imitating the structure of the GEM, a thick GEM-like multiplier which has the similar function with that of the GEM is designed and manufactured. The characteristics of the thick GEM-like multiplier increasing electron energy deposition in absorbing medium has been experimentally studied. The results indicate that the energy deposition gain of x-ray photoelectron in medium is apparent, and the maximum energy deposition can increase by more than 40%. Some suggestions of further increasing the energy deposition are given, and the future application of the way of increasing the x-ray photoelectron energy deposition by the thick GEM-like multiplier in hard x-ray imaging is prospected. (authors)

Relationship between energy deposition and shock wave phenomenon in an underwater electrical wire explosion

Science.gov (United States)

Han, Ruoyu; Zhou, Haibin; Wu, Jiawei; Qiu, Aici; Ding, Weidong; Zhang, Yongmin

2017-09-01

An experimental study of pressure waves generated by an exploding copper wire in a water medium is performed. We examined the effects of energy deposited at different stages on the characteristics of the resulting shock waves. In the experiments, a microsecond time-scale pulsed current source was used to explode a 300-μm-diameter, 4-cm-long copper wire with initial stored energies ranging from 500 to 2700 J. Our experimental results indicated that the peak pressure (4.5-8.1 MPa) and energy (49-287 J) of the shock waves did not follow a simple relationship with any electrical parameters, such as peak voltage or deposited energy. Conversely, the impulse had a quasi-linear relationship with the parameter Π. We also found that the peak pressure was mainly influenced by the energy deposited before separation of the shock wave front and the discharge plasma channel (DPC). The decay time constant of the pressure waveform was affected by the energy injection after the separation. These phenomena clearly demonstrated that the deposited energy influenced the expansion of the DPC and affected the shock wave characteristics.

Evaluation of burnup characteristics and energy deposition during NSRR pulse irradiation tests on irradiated BWR fuels

International Nuclear Information System (INIS)

Nakamura, Takehiko; Yoshinaga, Makio

2000-11-01

Pulse irradiation tests of irradiated fuel are performed in the Nuclear Safety Research Reactor (NSRR) to investigate the fuel behavior under Reactivity Initiated Accident Conditions (RIA). The severity of the RIA is represented by energy deposition or peak fuel enthalpy during the power excursion. In case of the irradiated fuel tests, the energy deposition varies depending both on the amounts and distribution of residual fissile and neutron absorbing fission products generated during the base irradiation. Thus, proper fuel burnup characterization, especially for low enriched commercial fuels, is important, because plutonium (Pu) takes a large part of fissile and its generation depends on the neutron spectrum during the base irradiation. Fuel burnup calculations were conducted with ORIGEN2, RODBURN and SWAT codes for the BWR fuels tested in the NSRR. The calculation results were compared with the measured isotope concentrations and used for the NSRR neutron calculations to evaluate energy depositions of the test fuel. The comparison of the code calculations and the measurements revealed that the neutron spectrum change due to difference in void fraction altered Pu generation and energy deposition in the NSRR tests considerably. With the properly evaluated neutron spectrum, the combined burnup and NSRR neutron calculation gave reasonably good evaluation of the energy deposition. The calculations provided radial distributions of the fission product accumulation during the base irradiation and power distribution during the NSRR pulse irradiation, which were important for the evaluation of both burnup characteristics and fission gas release behavior. (author)

Energy deposition and thermal effects of runaway electrons in ITER-FEAT plasma facing components

International Nuclear Information System (INIS)

Maddaluno, G.; Maruccia, G.; Merola, M.; Rollet, S.

2003-01-01

The profile of energy deposited by runaway electrons (RAEs) of 10 or 50 MeV in International Thermonuclear Experimental Reactor-Fusion Energy Advanced Tokamak (ITER-FEAT) plasma facing components (PFCs) and the subsequent temperature pattern have been calculated by using the Monte Carlo code FLUKA and the finite element heat conduction code ANSYS. The RAE energy deposition density was assumed to be 50 MJ/m 2 and both 10 and 100 ms deposition times were considered. Five different configurations of PFCs were investigated: primary first wall armoured with Be, with and without protecting CFC poloidal limiters, both port limiter first wall options (Be flat tile and CFC monoblock), divertor baffle first wall, armoured with W. The analysis has outlined that for all the configurations but one (port limiter with Be flat tile) the heat sink and the cooling tube beneath the armour are well protected for both RAE energies and for both energy deposition times. On the other hand large melting (W, Be) or sublimation (C) of the surface layer occurs, eventually affecting the PFCs lifetime

Energy deposition and thermal effects of runaway electrons in ITER-FEAT plasma facing components

Science.gov (United States)

Maddaluno, G.; Maruccia, G.; Merola, M.; Rollet, S.

2003-03-01

The profile of energy deposited by runaway electrons (RAEs) of 10 or 50 MeV in International Thermonuclear Experimental Reactor-Fusion Energy Advanced Tokamak (ITER-FEAT) plasma facing components (PFCs) and the subsequent temperature pattern have been calculated by using the Monte Carlo code FLUKA and the finite element heat conduction code ANSYS. The RAE energy deposition density was assumed to be 50 MJ/m 2 and both 10 and 100 ms deposition times were considered. Five different configurations of PFCs were investigated: primary first wall armoured with Be, with and without protecting CFC poloidal limiters, both port limiter first wall options (Be flat tile and CFC monoblock), divertor baffle first wall, armoured with W. The analysis has outlined that for all the configurations but one (port limiter with Be flat tile) the heat sink and the cooling tube beneath the armour are well protected for both RAE energies and for both energy deposition times. On the other hand large melting (W, Be) or sublimation (C) of the surface layer occurs, eventually affecting the PFCs lifetime.

Stopping and energy deposition of hadrons in target nuclei

International Nuclear Information System (INIS)

Strugalski, Z.

1983-01-01

In an analysis of pion-xenon nucleus collisions at 2.34-9 GeV/c momentum events are identified in which incident pions were completely stopped and deposited their energy in target nucleus. Probability of appearance of such ''stopped'' events among any-type pion-xenon collision events depends on the incident pion momentum and is: approximately 0.15 at 2.34 GeV/c, approximately 0.02 at 3.5 GeV/c, and approximately 0 at higher momenta. Formula expressing probability of appearance of the ''stopped'' events is derived. Range-energy relation in nuclear matter for pions and protons is given

ATLAS Level-1 Calorimeter Trigger: Initial Timing and Energy Calibration

CERN Document Server

Childers, J T; The ATLAS collaboration

2010-01-01

The ATLAS Level-1 Calorimeter Trigger identifies high-pT objects in the Liquid Argon and Tile Calorimeters with a fixed latency of ~2.0 µs using a hardware-based, pipelined system built with custom electronics. The Preprocessor Module conditions and digitizes about 7200 pre-summed analogue signals from the calorimeters at the LHC bunch-crossing frequency of 40 MHz, and performs bunch-crossing identification (BCID) and deposited energy measurement for each input signal. This information is passed to further processors for object classification and total energy calculation, and the results used to make the Level-1 trigger decision for the ATLAS detector. The BCID and energy measurement in the trigger depend on precise timing adjustment to achieve correct sampling of the input signal peak. Test pulses from the calorimeters were analysed to derive the initial timing and energy calibration, and first data from the LHC restart in autumn 2009 and early 2010 were used for validation and further optimization. The res...

Depth-resolved detection and process dependence of traps at ultrathin plasma-oxidized and deposited SiO2/Si interfaces

International Nuclear Information System (INIS)

Brillson, L. J.; Young, A. P.; White, B. D.; Schaefer, J.; Niimi, H.; Lee, Y. M.; Lucovsky, G.

2000-01-01

Low-energy electron-excited nanoluminescence spectroscopy reveals depth-resolved optical emission associated with traps near the interface between ultrathin SiO 2 deposited by plasma-enhanced chemical vapor deposition on plasma-oxidized crystalline Si. These near-interface states exhibit a strong dependence on local chemical bonding changes introduced by thermal/gas processing, layer-specific nitridation, or depth-dependent radiation exposure. The depth-dependent results provide a means to test chemical and structural bond models used to develop advanced dielectric-semiconductor junctions. (c) 2000 American Vacuum Society

Optimization design of energy deposition on single expansion ramp nozzle

Science.gov (United States)

Ju, Shengjun; Yan, Chao; Wang, Xiaoyong; Qin, Yupei; Ye, Zhifei

2017-11-01

Optimization design has been widely used in the aerodynamic design process of scramjets. The single expansion ramp nozzle is an important component for scramjets to produces most of thrust force. A new concept of increasing the aerodynamics of the scramjet nozzle with energy deposition is presented. The essence of the method is to create a heated region in the inner flow field of the scramjet nozzle. In the current study, the two-dimensional coupled implicit compressible Reynolds Averaged Navier-Stokes and Menter's shear stress transport turbulence model have been applied to numerically simulate the flow fields of the single expansion ramp nozzle with and without energy deposition. The numerical results show that the proposal of energy deposition can be an effective method to increase force characteristics of the scramjet nozzle, the thrust coefficient CT increase by 6.94% and lift coefficient CN decrease by 26.89%. Further, the non-dominated sorting genetic algorithm coupled with the Radial Basis Function neural network surrogate model has been employed to determine optimum location and density of the energy deposition. The thrust coefficient CT and lift coefficient CN are selected as objective functions, and the sampling points are obtained numerically by using a Latin hypercube design method. The optimized thrust coefficient CT further increase by 1.94%, meanwhile, the optimized lift coefficient CN further decrease by 15.02% respectively. At the same time, the optimized performances are in good and reasonable agreement with the numerical predictions. The findings suggest that scramjet nozzle design and performance can benefit from the application of energy deposition.

Space-time dependence between energy sources and climate related energy production

Science.gov (United States)

Engeland, Kolbjorn; Borga, Marco; Creutin, Jean-Dominique; Ramos, Maria-Helena; Tøfte, Lena; Warland, Geir

2014-05-01

The European Renewable Energy Directive adopted in 2009 focuses on achieving a 20% share of renewable energy in the EU overall energy mix by 2020. A major part of renewable energy production is related to climate, called "climate related energy" (CRE) production. CRE production systems (wind, solar, and hydropower) are characterized by a large degree of intermittency and variability on both short and long time scales due to the natural variability of climate variables. The main strategies to handle the variability of CRE production include energy-storage, -transport, -diversity and -information (smart grids). The three first strategies aim to smooth out the intermittency and variability of CRE production in time and space whereas the last strategy aims to provide a more optimal interaction between energy production and demand, i.e. to smooth out the residual load (the difference between demand and production). In order to increase the CRE share in the electricity system, it is essential to understand the space-time co-variability between the weather variables and CRE production under both current and future climates. This study presents a review of the literature that searches to tackle these problems. It reveals that the majority of studies deals with either a single CRE source or with the combination of two CREs, mostly wind and solar. This may be due to the fact that the most advanced countries in terms of wind equipment have also very little hydropower potential (Denmark, Ireland or UK, for instance). Hydropower is characterized by both a large storage capacity and flexibility in electricity production, and has therefore a large potential for both balancing and storing energy from wind- and solar-power. Several studies look at how to better connect regions with large share of hydropower (e.g., Scandinavia and the Alps) to regions with high shares of wind- and solar-power (e.g., green battery North-Sea net). Considering time scales, various studies consider wind

Low-energy ion-beam deposition apparatus equipped with surface analysis system

International Nuclear Information System (INIS)

Ohno, Hideki; Aoki, Yasushi; Nagai, Siro.

1994-10-01

A sophisticated apparatus for low energy ion beam deposition (IBD) was installed at Takasaki Radiation Chemistry Research Establishment of JAERI in March 1991. The apparatus is composed of an IBD system and a real time/in-situ surface analysis system for diagnosing deposited thin films. The IBD system provides various kinds of low energy ion down to 10 eV with current density of 10 μA/cm 2 and irradiation area of 15x15 mm 2 . The surface analysis system consists of RHEED, AES, ISS and SIMS. This report describes the characteristics and the operation procedure of the apparatus together with some experimental results on depositing thin carbon films. (author)

Characteristics of toroidal energy deposition asymmetries in ASDEX

International Nuclear Information System (INIS)

Evans, T.E.; Neuhauser, J.; Leuterer, F.; Mueller, E.R.

1990-01-01

Large toroidal and poloidal asymmetries with characteristics which are sensitively dependent on q a , the vertical position of the plasma, and the type of additional heating are observed in the energy flow to the ASDEX divertor target plates. The largest asymmetries and total energy depositions are observed during lower hybrid wave injection experiments with approximately 50% of the input energy going to the combined divertor targets and shields. A maximum localized energy density loading of 10 MJ/m 2 is typical under these conditions. Measurements of the asymmetries are consistent with a model in which magnetic islands and ergodicity due to intrinsic magnetic perturbations dominate the energy transpot across the primary magnetic separatrix. The results emphasize the essential role of resonant magnetic perturbations in determining the performance of tokamaks and demonstrate that non-axisymmetric effects caused by small perturbations become increasingly important in determining the transport properties as the injected power is increased. (orig.)

Constitutive model with time-dependent deformations

DEFF Research Database (Denmark)

Krogsbøll, Anette

1998-01-01

are common in time as well as size. This problem is adressed by means of a new constitutive model for soils. It is able to describe the behavior of soils at different deformation rates. The model defines time-dependent and stress-related deformations separately. They are related to each other and they occur...... was the difference in time scale between the geological process of deposition (millions of years) and the laboratory measurements of mechanical properties (minutes or hours). In addition, the time scale relevant to the production history of the oil field was interesting (days or years)....

Heavy Ion Induced Degradation in SiC Schottky Diodes: Bias and Energy Deposition Dependence

Science.gov (United States)

Javanainen, Arto; Galloway, Kenneth F.; Nicklaw, Christopher; Bosser, Alexandre L.; Ferlet-Cavrois, Veronique; Lauenstein, Jean-Marie; Pintacuda, Francesco; Reed, Robert A.; Schrimpf, Ronald D.; Weller, Robert A.;

Electron-stimulated purification of platinum nanostructures grown via focused electron beam induced deposition

Directory of Open Access Journals (Sweden)

Brett B. Lewis

2015-04-01

Full Text Available Platinum–carbon nanostructures deposited via electron beam induced deposition from MeCpPt(IVMe3 are purified during a post-deposition electron exposure treatment in a localized oxygen ambient at room temperature. Time-dependent studies demonstrate that the process occurs from the top–down. Electron beam energy and current studies demonstrate that the process is controlled by a confluence of the electron energy loss and oxygen concentration. Furthermore, the experimental results are modeled as a 2nd order reaction which is dependent on both the electron energy loss density and the oxygen concentration. In addition to purification, the post-deposition electron stimulated oxygen purification process enhances the resolution of the EBID process due to the isotropic carbon removal from the as-deposited materials which produces high-fidelity shape retention.

Monte Carlo simulation of energy deposition by low-energy electrons in molecular hydrogen

Science.gov (United States)

Heaps, M. G.; Furman, D. R.; Green, A. E. S.

1975-01-01

A set of detailed atomic cross sections has been used to obtain the spatial deposition of energy by 1-20-eV electrons in molecular hydrogen by a Monte Carlo simulation of the actual trajectories. The energy deposition curve (energy per distance traversed) is quite peaked in the forward direction about the entry point for electrons with energies above the threshold of the electronic states, but the peak decreases and broadens noticeably as the electron energy decreases below 10 eV (threshold for the lowest excitable electronic state of H2). The curve also assumes a very symmetrical shape for energies below 10 eV, indicating the increasing importance of elastic collisions in determining the shape of the curve, although not the mode of energy deposition.

Inter-dependence not Over-dependence: Reducing Urban Transport Energy Dependence

Energy Technology Data Exchange (ETDEWEB)

Saunders, Michael James; Rodrigues da Silva, Antonio Nelson

2007-07-01

A major issue of concern in today's world is urban transport energy dependence and energy supply security. In an energy inter-dependent world, energy over-dependence brings risks to urban transport systems. Many urban areas are over-dependent on finite petroleum resources for transport. New technology and the development and integration of renewable resources into transport energy systems may reduce some of the current transport energy dependence of urban areas. However, the most effective means of reducing energy dependence is to first design urban areas for this condition. An urban policy framework is proposed that requires transport energy dependence to be measured and controlled in the urban development process. A new tool has been created for this purpose, the Transport Energy Specification (TES), which measures transport energy dependence of urban areas. This creates the possibility for cities to regulate urban development with respect to energy dependence. Trial assessments were performed in Germany, New Zealand and Brazil; initial analysis by transport and government professionals shows promise of this tool being included into urban policy. The TES combined with a regulatory framework has the potential to significantly reduce transport energy consumption and dependence in urban areas in the future. (auth)

Enhanced energy deposition symmetry by hot electron transport

International Nuclear Information System (INIS)

Wilson, D.; Mack, J.; Stover, E.; VanHulsteyn, D.; McCall, G.; Hauer, A.

1981-01-01

High energy electrons produced by resonance absorption carry the CO 2 laser energy absorbed in a laser fusion pellet. The symmetrization that can be achieved by lateral transport of the hot electrons as they deposit their energy is discussed. A K/sub α/ experiment shows a surprising symmetrization of energy deposition achieved by adding a thin layer of plastic to a copper sphere. Efforts to numerically model this effect are described

ATLAS level-1 calorimeter trigger hardware: initial timing and energy calibration

CERN Document Server

Childers, JT; The ATLAS collaboration

2010-01-01

The ATLAS Level-1 Calorimeter Trigger identifies high-pT objects in the Liquid Argon and Tile Calorimeters with a fixed latency of up to 2.4 microseconds using a hardware-based, pipelined system built with custom electronics. The Preprocessor Module conditions and digitizes about 7200 pre-summed analogue signals from the calorimeters at the LHC bunch-crossing frequency of 40 MHz, and performs bunch-crossing identification (BCID) and deposited energy measurement for each input signal. This information is passed to further processors for object classification and total energy calculation, and the results are used to make the Level-1 trigger decision for the ATLAS detector. The BCID and energy measurement in the trigger depend on precise timing adjustments to achieve correct sampling of the input signal peak. Test pulses from the calorimeters were analysed to derive the initial timing and energy calibration, and first data from the LHC restart in autumn 2009 and early 2010 were used for validation and further op...

Time-dependent wave-packet study of the direct low-energy dissociative recombination of HD+

International Nuclear Information System (INIS)

Orel, A. E.

2000-01-01

Wave-packet methods involving the numerical solution of the time-dependent Schroedinger equation have been used with great success in the calculation of cross sections for dissociative recombination of molecular ions by electron impact in the high energy region where the ''boomerang'' model [L. Dube and A. Herzenberg, Phys. Rev. A 11, 1314 (1975)] is valid. We extend this method to study low-energy dissociative recombination where this approximation is no longer appropriate. We apply the method to the ''direct'' low-energy dissociative recombination of HD + . Our results are in excellent agreement with calculations using the multichannel quantum defect method. (c) 2000 The American Physical Society

Time-dependent delayed signatures from energetic photon interrogations

International Nuclear Information System (INIS)

Norman, Daren R.; Jones, James L.; Blackburn, Brandon W.; Haskell, Kevin J.; Johnson, James T.; Watson, Scott M.; Hunt, Alan W.; Spaulding, Randy; Harmon, Frank

2007-01-01

Pulsed photonuclear interrogation environments generated by 8-24 MeV electron linac are rich with time-dependent, material-specific, radiation signatures. Nitrogen-based explosives and nuclear materials can be detected by exploiting these signatures in different delayed-time regions. Numerical and experimental results presented in this paper show the unique time and energy dependence of these signatures. It is shown that appropriate delayed-time windows are essential to acquire material-specific signatures in pulsed photonuclear assessment environments. These developments demonstrate that pulsed, high-energy, photon-inspection environments can be exploited for time-dependent, material-specific signatures through the proper operation of specialized detectors and detection methods

X-ray amplifier energy deposition scaling with channeled propagation

International Nuclear Information System (INIS)

Boyer, K.; Luk, T.S.; McPherson, A.

1991-01-01

The spatial control of the energy deposited for excitation of an x-ray amplifier plays an important role in the fundamental scaling relationship between the required energy, the gain and the wavelength. New results concerning the ability to establish confined modes of propagation of sort pulse radiation of sufficiently high intensity in plasmas lead to a sharply reduced need for the total energy deposited, since the concentration of deposited power can be very efficiently organized

Magnetic field effects on runaway electron energy deposition in plasma facing materials and components

International Nuclear Information System (INIS)

Niemer, K.A.; Gilligan, J.G.

1992-01-01

This paper reports magnetic field effects on runaway electron energy deposition in plasma facing materials and components is investigated using the Integrated TIGER Series. The Integrated TIGER Series is a set of time-independent coupled electron/photon Monte Carlo transport codes which perform photon and electron transport, with or without macroscopic electric and magnetic fields. A three-dimensional computational model of 100 MeV electrons incident on a graphite block was used to simulate runawayelectrons striking a plasma facing component at the edge of a tokamak. Results show that more energy from runaway electrons will be deposited in a material that is in the presence of a magnetic field than in a material that is in the presence of no field. For low angle incident runaway electrons in a strong magnetic field, the majority of the increased energy deposition is near the material surface with a higher energy density. Electrons which would have been reflected with no field, orbit the magnetic field lines and are redeposited in the material surface, resulting in a substantial increase in surface energy deposition. Based on previous studies, the higher energy deposition and energy density will result in higher temperatures which are expected to cause more damage to a plasma facing component

Monte Carlo calculation of the energy deposited in the KASCADE GRANDE detectors

International Nuclear Information System (INIS)

Mihai, Constantin

2004-01-01

The energy deposited by protons, electrons and positrons in the KASCADE GRANDE detectors is calculated with a simple and fast Monte Carlo method. The KASCADE GRANDE experiment (Forschungszentrum Karlsruhe, Germany), based on an array of plastic scintillation detectors, has the aim to study the energy spectrum of the primary cosmic rays around and above the 'knee' region of the spectrum. The reconstruction of the primary spectrum is achieved by comparing the data collected by the detectors with simulations of the development of the extensive air shower initiated by the primary particle combined with detailed simulations of the detector response. The simulation of the air shower development is carried out with the CORSIKA Monte Carlo code. The output file produced by CORSIKA is further processed with a program that estimates the energy deposited in the detectors by the particles of the shower. The standard method to calculate the energy deposit in the detectors is based on the Geant package from the CERN library. A new method that calculates the energy deposit by fitting the Geant based distributions with simpler functions is proposed in this work. In comparison with the method based on the Geant package this method is substantially faster. The time saving is important because the number of particles involved is large. (author)

Efficient exact-exchange time-dependent density-functional theory methods and their relation to time-dependent Hartree-Fock.

Science.gov (United States)

Hesselmann, Andreas; Görling, Andreas

2011-01-21

A recently introduced time-dependent exact-exchange (TDEXX) method, i.e., a response method based on time-dependent density-functional theory that treats the frequency-dependent exchange kernel exactly, is reformulated. In the reformulated version of the TDEXX method electronic excitation energies can be calculated by solving a linear generalized eigenvalue problem while in the original version of the TDEXX method a laborious frequency iteration is required in the calculation of each excitation energy. The lowest eigenvalues of the new TDEXX eigenvalue equation corresponding to the lowest excitation energies can be efficiently obtained by, e.g., a version of the Davidson algorithm appropriate for generalized eigenvalue problems. Alternatively, with the help of a series expansion of the new TDEXX eigenvalue equation, standard eigensolvers for large regular eigenvalue problems, e.g., the standard Davidson algorithm, can be used to efficiently calculate the lowest excitation energies. With the help of the series expansion as well, the relation between the TDEXX method and time-dependent Hartree-Fock is analyzed. Several ways to take into account correlation in addition to the exact treatment of exchange in the TDEXX method are discussed, e.g., a scaling of the Kohn-Sham eigenvalues, the inclusion of (semi)local approximate correlation potentials, or hybrids of the exact-exchange kernel with kernels within the adiabatic local density approximation. The lowest lying excitations of the molecules ethylene, acetaldehyde, and pyridine are considered as examples.

Time Resolved Deposition Measurements in NSTX

International Nuclear Information System (INIS)

Skinner, C.H.; Kugel, H.; Roquemore, A.L.; Hogan, J.; Wampler, W.R.

2004-01-01

Time-resolved measurements of deposition in current tokamaks are crucial to gain a predictive understanding of deposition with a view to mitigating tritium retention and deposition on diagnostic mirrors expected in next-step devices. Two quartz crystal microbalances have been installed on NSTX at a location 0.77m outside the last closed flux surface. This configuration mimics a typical diagnostic window or mirror. The deposits were analyzed ex-situ and found to be dominantly carbon, oxygen, and deuterium. A rear facing quartz crystal recorded deposition of lower sticking probability molecules at 10% of the rate of the front facing one. Time resolved measurements over a 4-week period with 497 discharges, recorded 29.2 (micro)g/cm 2 of deposition, however surprisingly, 15.9 (micro)g/cm 2 of material loss occurred at 7 discharges. The net deposited mass of 13.3 (micro)g/cm 2 matched the mass of 13.5 (micro)g/cm 2 measured independently by ion beam analysis. Monte Carlo modeling suggests that transient processes are likely to dominate the deposition

Effect of Energy Input on the Characteristic of AISI H13 and D2 Tool Steels Deposited by a Directed Energy Deposition Process

Science.gov (United States)

Park, Jun Seok; Park, Joo Hyun; Lee, Min-Gyu; Sung, Ji Hyun; Cha, Kyoung Je; Kim, Da Hye

2016-05-01

Among the many additive manufacturing technologies, the directed energy deposition (DED) process has attracted significant attention because of the application of metal products. Metal deposited by the DED process has different properties than wrought metal because of the rapid solidification rate, the high thermal gradient between the deposited metal and substrate, etc. Additionally, many operating parameters, such as laser power, beam diameter, traverse speed, and powder mass flow rate, must be considered since the characteristics of the deposited metal are affected by the operating parameters. In the present study, the effect of energy input on the characteristics of H13 and D2 steels deposited by a direct metal tooling process based on the DED process was investigated. In particular, we report that the hardness of the deposited H13 and D2 steels decreased with increasing energy input, which we discuss by considering microstructural observations and thermodynamics.

Examining the time dependence of DAMA's modulation amplitude

Science.gov (United States)

Kelso, Chris; Savage, Christopher; Sandick, Pearl; Freese, Katherine; Gondolo, Paolo

2018-03-01

If dark matter is composed of weakly interacting particles, Earth's orbital motion may induce a small annual variation in the rate at which these particles interact in a terrestrial detector. The DAMA collaboration has identified at a 9.3σ confidence level such an annual modulation in their event rate over two detector iterations, DAMA/NaI and DAMA/LIBRA, each with ˜ 7 years of observations. This data is well fit by a constant modulation amplitude for the two iterations of the experiment. We statistically examine the time dependence of the modulation amplitudes, which "by eye" appear to be decreasing with time in certain energy ranges. We perform a chi-squared goodness of fit test of the average modulation amplitudes measured by the two detector iterations which rejects the hypothesis of a consistent modulation amplitude at greater than 80, 96, and 99.6% for the 2-4, 2-5 and 2-6 keVee energy ranges, respectively. We also find that among the 14 annual cycles there are three ≳ 3σ departures from the average in our estimated data in the 5-6 keVee energy range. In addition, we examined several phenomenological models for the time dependence of the modulation amplitude. Using a maximum likelihood test, we find that descriptions of the modulation amplitude as decreasing with time are preferred over a constant modulation amplitude at anywhere between 1σ and 3σ , depending on the phenomenological model for the time dependence and the signal energy range considered. A time dependent modulation amplitude is not expected for a dark matter signal, at least for dark matter halo morphologies consistent with the DAMA signal. New data from DAMA/LIBRA-phase2 will certainly aid in determining whether any apparent time dependence is a real effect or a statistical fluctuation.

The dependence of the texture of tellurium thin films on vacuum deposition angle

International Nuclear Information System (INIS)

Cocks, F.H.; Peterson, M.J.; Jones, P.L.

1980-01-01

Vacuum-deposited tellurium thin films can show substantially different surface morphologies depending on the angle with which the vapor stream impinges on the substrate surface. These tellurium thin films have a tendency to grow as acicular crystallites but as the deposition angle is increased so that the vapor stream becomes tangential to the substrate surface the spacing between crystallites increases and approaches, at stream angles of approximately 80 0 from the normal, dimensions roughly once or twice the average wavelength of visible light. Such films may have application in solar energy collector systems because of the high absorptivity of sunlight shown by such films. Mechanisms which describe the tendency for crystallite spacing to increase with increasing angle are discussed. (Auth.)

ATLAS level-1 calorimeter trigger hardware: initial timing and energy calibration

International Nuclear Information System (INIS)

Childers, J T

2011-01-01

The ATLAS Level-1 Calorimeter Trigger identifies high-pT objects in the Liquid Argon and Tile Calorimeters with a fixed latency of up to 2.5μs using a hardware-based, pipelined system built with custom electronics. The Preprocessor Module conditions and digitizes about 7200 pre-summed analogue signals from the calorimeters at the LHC bunch-crossing frequency of 40 MHz, and performs bunch-crossing identification (BCID) and deposited energy measurement for each input signal. This information is passed to further processors for object classification and total energy calculation, and the results are used to make the Level-1 trigger decision for the ATLAS detector. The BCID and energy measurement in the trigger depend on precise timing adjustments to achieve correct sampling of the input signal peak. Test pulses from the calorimeters were analysed to derive the initial timing and energy calibration, and first data from the LHC restart in autumn 2009 and early 2010 were used for validation and further optimization. The results from these calibration measurements are presented.

Investigating energy deposition within cell populations using Monte Carlo simulations.

Science.gov (United States)

Oliver, Patricia A K; Thomson, Rowan M

2018-06-27

In this work, we develop multicellular models of healthy and cancerous human soft tissues, which are used to investigate energy deposition in subcellular targets, quantify the microdosimetric spread in a population of cells, and determine how these results depend on model details. Monte Carlo (MC) tissue models combining varying levels of detail on different length scales are developed: microscopically-detailed regions of interest (>1500 explicitly-modelled cells) are embedded in bulk tissue phantoms irradiated by photons (20 keV to 1.25 MeV). Specific energy (z; energy imparted per unit mass) is scored in nuclei and cytoplasm compartments using the EGSnrc user-code egs_chamber; specific energy mean, <z>, standard deviation, σ_z, and distribution, f(z,D), are calculated for a variety of macroscopic doses, D. MC-calculated f(z,D) are compared with normal distributions having the same mean and standard deviation. For mGy doses, there is considerable variation in energy deposition (microdosimetric spread) throughout a cell population: e.g., for 30 keV photons irradiating melanoma with 7.5 μm cell radius and 3 μm nuclear radius, σ_z/<z> for nuclear targets is 170%, and the fraction of nuclei receiving no energy deposition, f_z=0, is 0.31 for a dose of 10 mGy. If cobalt-60 photons are considered instead, then σ_z/<z> decreases to 84%, and f_z=0 decreases to 0.036. These results correspond to randomly arranged cells with cell/nucleus sizes randomly sampled from a normal distribution with a standard deviation of 1 μm. If cells are arranged in a hexagonal lattice and cell/nucleus sizes are uniform throughout the population, then σ_z/<z> decreases to 106% and 68% for 30 keV and cobalt-60,respectively; f_z=0

Dynamic energy spectrum and energy deposition in solid target by intense pulsed ion beams

Institute of Scientific and Technical Information of China (English)

Xiao Yu; Xiao-Yun Le; Zheng Liu; Jie Shen; Yu I.Isakova; Hao-Wen Zhong; Jie Zhang; Sha Yan; Gao-Long Zhang; Xiao-Fu Zhang

2017-01-01

A method for analyzing the dynamic energy spectrum of intense pulsed ion beam (IPIB) was proposed.Its influence on beam energy deposition in metal target was studied with IPIB produced by two types of magnetically insulated diodes (MID).The emission of IPIB was described with space charge limitation model,and the dynamic energy spectrum was further analyzed with time-of-flight method.IPIBs generated by pulsed accelerators of BIPPAB-450 (active MID) and TEMP-4M (passive MID) were studied.The dynamic energy spectrum was used to deduce the power density distribution of IPIB in the target with Monte Carlo simulation and infrared imaging diagnostics.The effect on the distribution and evolution of thermal field induced by the characteristics of IPIB dynamic energy spectrum was discussed.

Dissipative time-dependent quantum transport theory.

Science.gov (United States)

Zhang, Yu; Yam, Chi Yung; Chen, GuanHua

2013-04-28

A dissipative time-dependent quantum transport theory is developed to treat the transient current through molecular or nanoscopic devices in presence of electron-phonon interaction. The dissipation via phonon is taken into account by introducing a self-energy for the electron-phonon coupling in addition to the self-energy caused by the electrodes. Based on this, a numerical method is proposed. For practical implementation, the lowest order expansion is employed for the weak electron-phonon coupling case and the wide-band limit approximation is adopted for device and electrodes coupling. The corresponding hierarchical equation of motion is derived, which leads to an efficient and accurate time-dependent treatment of inelastic effect on transport for the weak electron-phonon interaction. The resulting method is applied to a one-level model system and a gold wire described by tight-binding model to demonstrate its validity and the importance of electron-phonon interaction for the quantum transport. As it is based on the effective single-electron model, the method can be readily extended to time-dependent density functional theory.

Films deposited from reactive sputtering of aluminum acetylacetonate under low energy ion bombardment

Energy Technology Data Exchange (ETDEWEB)

Battaglin, Felipe Augusto Darriba; Prado, Eduardo Silva; Cruz, Nilson Cristino da; Rangel, Elidiane Cipriano, E-mail: elidiane@sorocaba.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sorocaba, SP (Brazil). Lab. de Plasmas Tecnologicos; Caseli, Luciano [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil). Instituto de Ciencias Ambientais, Quimicas e Farmaceuticas; Silva, Tiago Fiorini da; Tabacniks, Manfredo Harri [Universidade de Sao Paulo (USP), SP (Brazil). Instituto de Fisica

2017-07-15

Films were deposited from aluminum acetylacetonate (Al(acac)3 ) using a methodology involving reactive sputtering and low energy ion bombardment. The plasma was generated by the application of radiofrequency power to the powder containing electrode and simultaneously, negative pulses were supplied to the electrode where the substrates were attached. It was investigated the effect of the duty cycle of the pulses (Δ) on the properties of the coatings. Association of ion bombardment to the deposition process increased film thickness, structure reticulation and organic content. Ions from the deposition environment were implanted at the film-air interface or underneath it. Morphology and topography were altered depending on Δ. Considering the enhancement of Δ, it affected the flux of ions reaching the depositing interface and then the deposition rate, H content, crosslinking degree and surface microstructure. Alumina groups were detected in the infrared spectra, whereas the precipitation of amorphous alumina was confirmed by X-ray diffraction. (author)

Advances in energy deposition theory

International Nuclear Information System (INIS)

Paretzke, H.G.

1980-01-01

In light of the fields of radiation protection and dosimetric problems in medicine, advances in the area of microscopic target related studies are discussed. Energy deposition is discussed with emphasis upon track structures of electrons and heavy charged particles and track computer calculations

Time dependence of the 137Cs resuspension factor on the Romanian territory after the Chernobyl accident

International Nuclear Information System (INIS)

Mihaila, B.; Cuculeanu, V.

1994-01-01

On the basis of the radioactivity levels in aerosol and atmospheric deposition samples due to the Chernobyl accident, the resuspension factor of 137 Cs as a four-parameter function has been inferred. The standard procedure to derive the dependence of resuspension on time assumes that the initial deposit is instantaneous. A simple method assuming a constant deposition rate over a fixed period has been proposed. Also, based on existing experimental data, an attempt was made to consider a realistic time dependence of the deposition rate to cope with the particular case of the Chernobyl accident. The differences between the two models are outlined. The Chernobyl direct deposit has been assumed to be the deposit measured between 30 April and 30 June 1986. The calculated values of the resuspension factor are consistent with the IAEA's recommended model and depend on the rainfall that occurred in June 1986 and the site-specific disturbance conditions during the first 100 d following 1 July 1986 and only on artificial disturbance by humans and vehicles after that. 16 refs., 5 figs., 3 tabs

Does a deformation of special relativity imply energy dependent photon time delays?

Science.gov (United States)

Carmona, J. M.; Cortés, J. L.; Relancio, J. J.

2018-01-01

Theoretical arguments in favor of energy dependent photon time delays from a modification of special relativity (SR) have met with recent gamma ray observations that put severe constraints on the scale of such deviations. We review the case of the generality of this theoretical prediction in the case of a deformation of SR and find that, at least in the simple model based on the analysis of photon worldlines which is commonly considered, there are many scenarios compatible with a relativity principle which do not contain a photon time delay. This will be the situation for any modified dispersion relation which reduces to E=\\vert p\\vert for photons, independently of the quantum structure of spacetime. This fact opens up the possibility of a phenomenologically consistent relativistic generalization of SR with a new mass scale many orders of magnitude below the Planck mass.

Science of mineral deposits and economics of energy

International Nuclear Information System (INIS)

Mackowsky, M.T.

1978-01-01

The availability of fossile energy carriers is investigated with regard to raw material reserves and their know deposits, by means of output and consumption. According to the author's opinion its discussion should have a priority over all discussions concerning energy crisis, energy supply and environmental protection. The author also touches the high measure of political problems beside the geoscientifical and technological problems of raw material supply. He briefly points to the general situation on the energy market with the help of data on stocks and consumption as given by the 10th International Energy Conference 1977 at Istambul and eventually deals with topics on mineral deposits science and uranium production. (HK) [de

Energy-enhanced atomic layer deposition : offering more processing freedom

NARCIS (Netherlands)

Potts, S.E.; Kessels, W.M.M.

2013-01-01

Atomic layer deposition (ALD) is a popular deposition technique comprising two or more sequential, self-limiting surface reactions, which make up an ALD cycle. Energy-enhanced ALD is an evolution of traditional thermal ALD methods, whereby energy is supplied to a gas in situ in order to convert a

Variational derivation of a time-dependent Hartree-Fock Hamiltonian

International Nuclear Information System (INIS)

Lichtner, P.C.; Griffin, J.J.; Schultheis, H.; Schultheis, R.; Volkov, A.B.

1979-01-01

The variational derivation of the time-dependent Hartree-Fock equation is reviewed. When norm-violating variations are included, a unique time-dependent Hartree-Fock Hamiltonian, which differs from that customarily used in time-dependent Hartree-Fock analyses, is implied. This variationally ''true'' Hartree-Fock Hamiltonian has the same expectation value as the exact Hamiltonian, equal to the average energy of the system. Since this quantity remains constant under time-dependent Hartree-Fock time evolution, we suggest the label ''constant '' for this form of time-dependent Hartree-Fock theory

Solar Energy Deposition Rates in the Mesosphere Derived from Airglow Measurements: Implications for the Ozone Model Deficit Problem

Science.gov (United States)

Mlynczak, Martin G.; Garcia, Rolando R.; Roble, Raymond G.; Hagan, Maura

2000-01-01

We derive rates of energy deposition in the mesosphere due to the absorption of solar ultraviolet radiation by ozone. The rates are derived directly from measurements of the 1.27-microns oxygen dayglow emission, independent of knowledge of the ozone abundance, the ozone absorption cross sections, and the ultraviolet solar irradiance in the ozone Hartley band. Fifty-six months of airglow data taken between 1982 and 1986 by the near-infrared spectrometer on the Solar-Mesosphere Explorer satellite are analyzed. The energy deposition rates exhibit altitude-dependent annual and semi-annual variations. We also find a positive correlation between temperatures and energy deposition rates near 90 km at low latitudes. This correlation is largely due to the semiannual oscillation in temperature and ozone and is consistent with model calculations. There is also a suggestion of possible tidal enhancement of this correlation based on recent theoretical and observational analyses. The airglow-derived rates of energy deposition are then compared with those computed by multidimensional numerical models. The observed and modeled deposition rates typically agree to within 20%. This agreement in energy deposition rates implies the same agreement exists between measured and modeled ozone volume mixing ratios in the mesosphere. Only in the upper mesosphere at midlatitudes during winter do we derive energy deposition rates (and hence ozone mixing ratios) consistently and significantly larger than the model calculations. This result is contrary to previous studies that have shown a large model deficit in the ozone abundance throughout the mesosphere. The climatology of solar energy deposition and heating presented in this paper is available to the community at the Middle Atmosphere Energy Budget Project web site at http://heat-budget.gats-inc.com.

Energy deposition in STARFIRE reactor components

International Nuclear Information System (INIS)

Gohar, Y.; Brooks, J.N.

1985-04-01

The energy deposition in the STARFIRE commercial tokamak reactor was calculated based on detailed models for the different reactor components. The heat deposition and the 14 MeV neutron flux poloidal distributions in the first wall were obtained. The poloidal surface heat load distribution in the first wall was calculated from the plasma radiation. The Monte Carlo method was used for the calculation to allow an accurate modeling for the reactor geometry

Monte Carlo simulations used to calculate the energy deposited in the coronary artery lumen as a function of iodine concentration and photon energy.

Science.gov (United States)

Hocine, Nora; Meignan, Michel; Masset, Hélène

2018-04-01

To better understand the risks of cumulative medical X-ray investigations and the possible causal role of contrast agent on the coronary artery wall, the correlation between iodinated contrast media and the increase of energy deposited in the coronary artery lumen as a function of iodine concentration and photon energy is investigated. The calculations of energy deposition have been performed using Monte Carlo (MC) simulation codes, namely PENetration and Energy LOss of Positrons and Electrons (PENELOPE) and Monte Carlo N-Particle eXtended (MCNPX). Exposure of a cylinder phantom, artery and a metal stent (AISI 316L) to several X-ray photon beams were simulated. For the energies used in cardiac imaging the energy deposited in the coronary artery lumen increases with the quantity of iodine. Monte Carlo calculations indicate a strong dependence of the energy enhancement factor (EEF) on photon energy and iodine concentration. The maximum value of EEF is equal to 25; this factor is showed for 83 keV and for 400 mg Iodine/mL. No significant impact of the stent is observed on the absorbed dose in the artery for incident X-ray beams with mean energies of 44, 48, 52 and 55 keV. A strong correlation was shown between the increase in the concentration of iodine and the energy deposited in the coronary artery lumen for the energies used in cardiac imaging and over the energy range between 44 and 55 keV. The data provided by this study could be useful for creating new medical imaging protocols to obtain better diagnostic information with a lower level of radiation exposure.

Cosmologies with a time dependent vacuum

International Nuclear Information System (INIS)

Sola, Joan

2011-01-01

The idea that the cosmological term Λ should be a time dependent quantity in cosmology is a most natural one. It is difficult to conceive an expanding universe with a strictly constant vacuum energy density, ρ Λ = Λ/(8π G), namely one that has remained immutable since the origin of time. A smoothly evolving vacuum energy density ρ Λ = ρ Λ (ξ(t)) that inherits its time-dependence from cosmological functions ξ = ξ(t), such as the Hubble rate H(t) or the scale factor a(t), is not only a qualitatively more plausible and intuitive idea, but is also suggested by fundamental physics, in particular by quantum field theory (QFT) in curved space-time. To implement this notion, is not strictly necessary to resort to ad hoc scalar fields, as usually done in the literature (e.g. in quintessence formulations and the like). A 'running' Λ term can be expected on very similar grounds as one expects (and observes) the running of couplings and masses with a physical energy scale in QFT. Furthermore, the experimental evidence that the equation of state (EOS) of the dark energy (DE) could be evolving with time/redshift (including the possibility that it might currently behave phantom-like) suggests that a time-variable Λ = Λ(t) term (possibly accompanied by a variable Newton's gravitational coupling too, G = G(t)) could account in a natural way for all these features. Remarkably enough, a class of these models (the 'new cosmon') could even be the clue for solving the old cosmological constant problem, including the coincidence problem.

Hartree--Fock time-dependent problem

Energy Technology Data Exchange (ETDEWEB)

Bove, A; Fano, G [Bologna Univ. (Italy). Istituto di Fisica; Istituto Nazionale di Fisica Nucleare, Bologna (Italy)); Da Prato, G [Rome Univ. (Italy). Istituto di Matematica

1976-06-01

A previous result is generalized. An existence and uniqueness theorem is proved for the Hartree--Fock time-dependent problem in the case of a finite Fermi system interacting via a two body potential which is supposed to be dominated by the kinetic energy part of the one-particle Hamiltonian.

Selfsimilar time dependent shock structures

International Nuclear Information System (INIS)

Beck, R.; Drury, L.O.

1985-01-01

Diffusive shock acceleration as an astrophysical mechanism for accelerating charged particles has the advantage of being highly efficient. This means however that the theory is of necessity nonlinear; the reaction of the accelerated particles on the shock structure and the acceleration process must be self-consistently included in any attempt to develop a complete theory of diffusive shock acceleration. Considerable effort has been invested in attempting, at least partially, to do this and it has become clear that in general either the maximum particle energy must be restricted by introducing additional loss processes into the problem or the acceleration must be treated as a time dependent problem (Drury, 1984). It is concluded that stationary modified shock structures can only exist for strong shocks if additional loss processes limit the maximum energy a particle can attain. This is certainly possible and if it occurs the energy loss from the shock will lead to much greater shock compressions. It is however equally possible that no such processes exist and we must then ask what sort of nonstationary shock structure develops. The same argument which excludes stationary structures also rules out periodic solutions and indeed any solution where the width of the shock remains bounded. It follows that the width of the shock must increase secularly with time and it is natural to examine the possibility of selfsimilar time dependent solutions

Selfsimilar time dependent shock structures

Science.gov (United States)

Beck, R.; Drury, L. O.

1985-01-01

Diffusive shock acceleration as an astrophysical mechanism for accelerating charged particles has the advantage of being highly efficient. This means however that the theory is of necessity nonlinear; the reaction of the accelerated particles on the shock structure and the acceleration process must be self-consistently included in any attempt to develop a complete theory of diffusive shock acceleration. Considerable effort has been invested in attempting, at least partially, to do this and it has become clear that in general either the maximum particle energy must be restricted by introducing additional loss processes into the problem or the acceleration must be treated as a time dependent problem (Drury, 1984). It is concluded that stationary modified shock structures can only exist for strong shocks if additional loss processes limit the maximum energy a particle can attain. This is certainly possible and if it occurs the energy loss from the shock will lead to much greater shock compressions. It is however equally possible that no such processes exist and we must then ask what sort of nonstationary shock structure develops. The ame argument which excludes stationary structures also rules out periodic solutions and indeed any solution where the width of the shock remains bounded. It follows that the width of the shock must increase secularly with time and it is natural to examine the possibility of selfsimilar time dependent solutions.

Study of Energy Deposition and Activation for the LINAC4 Dump

CERN Document Server

Cerutti, F; Mauro, E; Mereghetti, A; Silari, M; CERN. Geneva. AB Department

2008-01-01

This document provides estimates of energy deposition and activation for the dump of the future LINAC4 accelerator. Detailed maps of power density deposited in the dump are given, allowing to perform further thermo mechanical studies. Residual dose rates at a few cooling times for different irradiation scenarios have been calculated. Moreover, the air activation has been evaluated and doses to the reference population group and to a worker intervening in the cave at the shutdown have been predicted. Calculations were performed with the Monte Carlo particle transport and interaction code FLUKA.

TLD gamma-ray energy deposition measurements in the zero energy fast reactor ZEBRA

International Nuclear Information System (INIS)

Knipe, A.D.

1977-01-01

A recent study of gamma-ray energy deposition was carried out in the Zebra reactor at AEE Winfrith during a collaborative programme between the UKAEA and PNC of Japan. The programme was given the title MOZART. This paper describes the TLD experiments in the MOZART MZB assembly and discusses the technique and various corrections necessary to relate the measured quantity to the calculated energy deposition

Short review on chemical bath deposition of thin film and characterization

Energy Technology Data Exchange (ETDEWEB)

Mugle, Dhananjay, E-mail: dhananjayforu@gmail.com; Jadhav, Ghanshyam, E-mail: ghjadhav@rediffmail.com [Depertment of Physics, Shri Chhatrapati Shivaji College, Omerga-413606 (India)

2016-05-06

This reviews the theory of early growth of the thin film using chemical deposition methods. In particular, it critically reviews the chemical bath deposition (CBD) method for preparation of thin films. The different techniques used for characterizations of the chemically films such as X-ray diffractometer (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Electrical conductivity and Energy Dispersive Spectroscopy (EDS) are discussed. Survey shows the physical and chemical properties solely depend upon the time of deposition, temperature of deposition.

A novel method of calculating the energy deposition curve of nanosecond pulsed surface dielectric barrier discharge

International Nuclear Information System (INIS)

He, Kun; Wang, Xinying; Lu, Jiayu; Cui, Quansheng; Pang, Lei; Di, Dongxu; Zhang, Qiaogen

2015-01-01

To obtain the energy deposition curve is very important in the fields to which nanosecond pulse dielectric barrier discharges (NPDBDs) are applied. It helps the understanding of the discharge physics and fast gas heating. In this paper, an equivalent circuit model, composed of three capacitances, is introduced and a method of calculating the energy deposition curve is proposed for a nanosecond pulse surface dielectric barrier discharge (NPSDBD) plasma actuator. The capacitance C d and the energy deposition curve E R are determined by mathematically proving that the mapping from C d to E R is bijective and numerically searching one C d that satisfies the requirement for E R to be a monotonically non-decreasing function. It is found that the value of capacitance C d varies with the amplitude of applied pulse voltage due to the change of discharge area and is dependent on the polarity of applied voltage. The bijectiveness of the mapping from C d to E R in nanosecond pulse volumetric dielectric barrier discharge (NPVDBD) is demonstrated and the feasibility of the application of the new method to NPVDBD is validated. This preliminarily shows a high possibility of developing a unified approach to calculate the energy deposition curve in NPDBD. (paper)

CTS and CZTS for solar cells made by pulsed laser deposition and pulsed electron deposition

DEFF Research Database (Denmark)

Ettlinger, Rebecca Bolt

This thesis concerns the deposition of thin films for solar cells using pulsed laser deposition (PLD) and pulsed electron deposition (PED). The aim was to deposit copper tin sulfide (CTS) and zinc sulfide (ZnS) by pulsed laser deposition to learn about these materials in relation to copper zinc tin...... time. We compared the results of CZTS deposition by PLD at DTU in Denmark to CZTS made by PED at IMEM-CNR, where CIGS solar cells have successfully been fabricated at very low processing temperatures. The main results of this work were as follows: Monoclinic-phase CTS films were made by pulsed laser...... deposition followed by high temperature annealing. The films were used to understand the double band gap that we and other groups observed in the material. The Cu-content of the CTS films varied depending on the laser fluence (the laser energy per pulse and per area). The material transfer from...

Exact norm-conserving stochastic time-dependent Hartree-Fock

International Nuclear Information System (INIS)

Tessieri, Luca; Wilkie, Joshua; Cetinbas, Murat

2005-01-01

We derive an exact single-body decomposition of the time-dependent Schroedinger equation for N pairwise interacting fermions. Each fermion obeys a stochastic time-dependent norm-preserving wave equation. As a first test of the method, we calculate the low energy spectrum of helium. An extension of the method to bosons is outlined

Response of temperature and density profiles to heat deposition profile and its impact on global scaling in LHD

International Nuclear Information System (INIS)

Yamada, H.

2002-01-01

Significant density dependence of the energy confinement time as described in the ISS95 scaling has been demonstrated in the extended parameter regimes in LHD. However, recent experiments have indicated that this density dependence is lost at a certain density under specific conditions. This paper discusses the cause of this saturation and related characteristics of anomalous transport. The saturation of the energy confinement time is observed in the density ramp-up phase of NBI heated plasmas. In contrast to the global energy confinement time, the local heat conduction coefficient still indicates the temperature dependence which is a companion to the density dependence of the energy confinement time. The apparent contradiction between the global confinement and the local transport can be attributed to the change of the heat deposition profile. Through this study, the response of temperature and density profiles to the heat deposition profile is highlighted, which is contrasted to the concept of stiffness or profile consistency observed in tokamaks. The major anomalous transport models based on ITG/TEM and interchange/ballooning modes are assessed. (author)

Effect of reaction time on structural, morphology and optical properties of ZnO nanoflakes prepared by chemical bath deposition method

Energy Technology Data Exchange (ETDEWEB)

Molefe, F.V.; Koao, L.F., E-mail: koaolf@qwa.ufs.ac.za; Dolo, J.J.; Dejene, B.F.

2014-04-15

ZnO nanoflakes have been successfully synthesized by the chemical bath deposition (CBD) method for different reaction times. X-ray diffraction (XRD) results confirm the initial formation of the cubic ZnO structure. However, increasing the reaction time resulted into the emergence of the well-known hexagonal wurtzite structure of ZnO. Scanning electron microscopy images showed the presence of agglomerated nanoflakes. The morphology was found not to depend on synthesis time. UV–vis spectra showed a partially increase in the percentage reflectance and the absorption edges red shifted to the higher wavelength with an increase in synthesis time. The highest band gap energy was obtained for ZnO synthesized for 1 min, with its estimated band gap energy of 3.91±0.08 eV. The estimated band gap decreased with an increase in the reaction time. The photoluminescent intensity of the emission peak at 473 nm decreased with an increase in reaction time.

1-D Van der Waals Foams Heated by Ion Beam Energy Deposition

International Nuclear Information System (INIS)

Zylstra, A.B.; Barnard, J.J.; More, R.M.

2009-01-01

One dimensional simulations of various initial average density aluminum foams (modeled as slabs of solid metal separated by low density regions) heated by volumetric energy deposition are conducted with a Lagrangian hydrodynamics code using a van der Waals equation of tate (EOS). The resulting behavior is studied to facilitate the design of future warm dense matter (WDM) experiments at LBNL. In the simulations the energy deposition ranges from 10 to 30 kJ/g and from 0.075 to 4.0 ns total pulse length, resulting in temperatures from approximately 1 o 4 eV. We study peak pressures and temperatures in the foams, expansion velocity, and the phase evolution. Five relevant time scales in the problem are identified. Additionally, we present a method for characterizing the level of inhomogeneity in a foam target as it is heated and the time it takes for a foam to homogenize.

Time-dependent density functional calculation of the energy loss of antiprotons colliding with metallic nanoshells

International Nuclear Information System (INIS)

Quijada, M.; Borisov, A.G.; Muino, R.D.

2008-01-01

Time-dependent density functional theory is used to study the interaction between antiprotons and metallic nanoshells. The ground state electronic properties of the nanoshell are obtained in the jellium approximation. The energy lost by the antiproton during the collision is calculated and compared to that suffered by antiprotons traveling in metal clusters. The resulting energy loss per unit path length of material in thin nanoshells is larger than the corresponding quantity for clusters. It is shown that the collision process can be interpreted as the antiproton crossing of two nearly bi-dimensional independent metallic systems. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Mechanical characteristics of a tool steel layer deposited by using direct energy deposition

Science.gov (United States)

Baek, Gyeong Yun; Shin, Gwang Yong; Lee, Eun Mi; Shim, Do Sik; Lee, Ki Yong; Yoon, Hi-Seak; Kim, Myoung Ho

2017-07-01

This study focuses on the mechanical characteristics of layered tool steel deposited using direct energy deposition (DED) technology. In the DED technique, a laser beam bonds injected metal powder and a thin layer of substrate via melting. In this study, AISI D2 substrate was hardfaced with AISI H13 and M2 metal powders for mechanical testing. The mechanical and metallurgical characteristics of each specimen were investigated via microstructure observation and hardness, wear, and impact tests. The obtained characteristics were compared with those of heat-treated tool steel. The microstructures of the H13- and M2-deposited specimens show fine cellular-dendrite solidification structures due to melting and subsequent rapid cooling. Moreover, the cellular grains of the deposited M2 layer were smaller than those of the H13 structure. The hardness and wear resistance were most improved in the M2-deposited specimen, yet the H13-deposited specimen had higher fracture toughness than the M2-deposited specimen and heat-treated D2.

Time-dependent scattering in resonance lines

International Nuclear Information System (INIS)

Kunasz, P.B.

1983-01-01

A numerical finite-difference method is presented for the problem of time-dependent line transfer in a finite slab in which material density is sufficiently low that the time of flight between scatterings greatly exceeds the relaxation time of the upper state of the scattering transition. The medium is assumed to scatter photons isotropically, with complete frequency redistribution. Numerical solutions are presented for a homogeneous, time-independent slab illuminated by an externally imposed radiation field which enters the slab at t = 0. Graphical results illustrate relaxation to steady state of trapped internal radiation, emergent energy, and emergent profiles. A review of the literature is also given in which the time-dependent line transfer problem is discussed in the context of recent analytical work

Time-dependent behavior of positrons in noble gases

International Nuclear Information System (INIS)

Wadehra, J.M.

1990-01-01

Both equilibrium and nonequilibrium behaviors of positrons in several noble gases are reviewed. Our novel procedure for obtaining the time-dependent behavior of various swarm parameters -- such as the positron drift velocity, average positron energy, positron annihilation rate (or equivalently Z eff ) etc. -- for positrons in pure ambient gases subjected to external electrostatic fields is described. Summaries of time-dependent as well as electric field-dependent results for positron swarms in various noble gases are presented. New time-dependent results for positron swarms in neon are also described in detail. 36 refs., 4 figs., 3 tabs

Proton energy dependence of slow neutron intensity

International Nuclear Information System (INIS)

Teshigawara, Makoto; Harada, Masahide; Watanabe, Noboru; Kai, Tetsuya; Sakata, Hideaki; Ikeda, Yujiro

2001-01-01

The choice of the proton energy is an important issue for the design of an intense-pulsed-spallation source. The optimal proton beam energy is rather unique from a viewpoint of the leakage neutron intensity but no yet clear from the slow-neutron intensity view point. It also depends on an accelerator type. Since it is also important to know the proton energy dependence of slow-neutrons from the moderators in a realistic target-moderator-reflector assembly (TMRA). We studied on the TMRA proposed for Japan Spallation Neutron Source. The slow-neutron intensities from the moderators per unit proton beam power (MW) exhibit the maximum at about 1-2 GeV. At higher proton energies the intensity per MW goes down; at 3 and 50 GeV about 0.91 and 0.47 times as low as that at 1 GeV. The proton energy dependence of slow-neutron intensities was found to be almost the same as that of total neutron yield (leakage neutrons) from the same bare target. It was also found that proton energy dependence was almost the same for the coupled and decoupled moderators, regardless the different moderator type, geometry and coupling scheme. (author)

Plasma-polymerized perfluoro(methylcyclohexane) coating on ethylene propylene diene elastomer surface: Effect of plasma processing condition on the deposition kinetics, morphology and surface energy of the film

International Nuclear Information System (INIS)

Tran, N.D.; Dutta, N.K.; Choudhury, N. Roy

2005-01-01

Plasma polymerization of perfluoro (methylcyclohexane) was carried out under cold plasma process operated at 13.56 MHz to deposit pore-free, uniform, ultra-thin film on an ethylene propylene diene terpolymer (EPDM) substrate in a view to modify the surface characteristics. The plasma fluoropolymeric films were formed at different plasma treatment times (from 20 s to 16 min), applied powers (20 to 100 W) and precursor flow rates to produce high quality films in a controllable yet tunable fashion. Scanning electron microscopy was employed successfully to characterize the evolution of the morphological feature in the film and also to determine the thickness of the coating. The surface energy of the film was determined by sessile drop method using different solvents as probe liquids. It is observed that a pore-free homogeneous plasma polymer thin film is formed within 20 s of treatment time, however, the morphology of the film depends on the plasma processing conditions, such as plasma power, precursor flow rate and deposition time. With increased time and power at a constant flow rate, the morphology of the film progressively changes from flat smooth to globular and rough. The kinetics and activation energy of the plasma polymer film deposition process were also estimated. The surface energy of the EPDM substrate decreased dramatically with plasma coating, however, it appears to be independent of the treatment time

Dependence of hardness and impact energy on cooling time Δt8/5and temperature for S960QL

OpenAIRE

Samardžić, I.; Dunđer, M.; Vuherer, T.

2015-01-01

The paper deals with research into dependence of hardness and impact energy of thermal cycle simulated specimens of fine-grained structural steel S960QL on cooling time from 800 to 500 °C and on tested temperature. Results were obtained by measuring hardness of HV 10 and by experimental testing of Charpy notched tubes on instrumented Charpy hammer. Total impact energy, initiation energy and fracture propagation energy needed for occurrence of fracture is also elaborated. Key words:

Exact solution of a quantum forced time-dependent harmonic oscillator

Science.gov (United States)

Yeon, Kyu Hwang; George, Thomas F.; Um, Chung IN

1992-01-01

The Schrodinger equation is used to exactly evaluate the propagator, wave function, energy expectation values, uncertainty values, and coherent state for a harmonic oscillator with a time dependent frequency and an external driving time dependent force. These quantities represent the solution of the classical equation of motion for the time dependent harmonic oscillator.

Generalized Energy-Dependent Q Values for Fission

Energy Technology Data Exchange (ETDEWEB)

Vogt, R

2010-03-31

We extend Madland's parameterization of the energy release in fission to obtain the dependence of the fission Q value for major and minor actinides on the incident neutron energies in the range 0 {le} E{sub n} {le} 20 MeV. Our parameterization is based on the actinide evaluations recommended for the ENDF/B-VII.1 release. This paper describes the calculation of energydependent fission Q values based on the calculation of the prompt energy release in fission by Madland. This calculation was adopted for use in the LLNL ENDL database and then generalized to obtain the prompt fission energy release for all actinides. Here the calculation is further generalized to the total energy release in fission. There are several stages in a fission event, depending on the time scale. Neutrons and gammas may be emitted at any time during the fission event.While our discussion here is focussed on compound nucleus creation by an incident neutron, similar parameterizations could be obtained for incident gammas or spontaneous fission.

Measurement of the time dependent neutron energy spectrum in the 'DENA' plasma focus device

Energy Technology Data Exchange (ETDEWEB)

Abdollahzadeh, M [Department of Physics, Imam Husein University, PO Box 16575-347, Tehran (Iran, Islamic Republic of); Sadat kiai, S M [Nuclear Science and Technology Research Institute (NSTRI), Nuclear Science Research School, A.E.O.I., PO Box 14155-1339, Tehran (Iran, Islamic Republic of); Babazadeh, A R [Physics Department, Qom University, PO Box 37165, Qom (Iran, Islamic Republic of)

2008-10-15

An extended time of flight method is used to determine the time dependent neutron energy spectrum in the Filippove type 'Dena' plasma focus (90 kJ, 25 kV, 288 {mu}F), filled with deuterium gas. An array of 5 detectors containing NE-102 plastic scintillators+photomultipliers is used. The number and position of the detectors are determined by a Monte Carlo program and the MCNP code. This paper briefly describes the simulation method and presents the experimental measurements and their results. The mechanisms of neutron production (thermonuclear and non-thermonuclear) and their time variations are discussed.

Most critical collimator-mask-magnet sequence in the SPS-to-LHC transfer lines: energy deposition study.

CERN Document Server

Marzo, Matteo; Lechner, Anton; Vlachoudis, Vasilis

2017-01-01

This technical note refers to a study on the relation between the impact conditions of the SPS 450GeV proton beam and the energy deposited downstream the Target Collimator Dump In- jection Long (TCDIL) collimators [1], in the SPS-to-LHC transfer lines TI2 and TI8. Such an analysis is relevant in order to simulate the worst scenario of failure, in case the beam impacts on the TCDIL collimator’s jaw, in the frame of the LHC Injectors Upgrade (LIU), in view of the High Luminosity LHC (HL-LHC) phase. Previous studies already showed the dependency of the energy deposited in the downstream masks on the collimators-masks distance [2]. In absence of a (realistic) impact parameter, we perform now a study to select the most pessimistic one, trying to understand the origin of the various components responsible for the energy deposition on the downstream mask and magnet. The set up of the Monte Carlo FLUKA [3] [4] simulations and the most relevant results will be presented in this document. A sensitivity analysis was a...

Effects of nitrogen ion implantation time on tungsten films deposited by DC magnetron sputtering on AISI 410 martensitic stainless steel

Energy Technology Data Exchange (ETDEWEB)

Malau, Viktor, E-mail: malau@ugm.ac.id; Ilman, Mochammad Noer, E-mail: noer-ilman@yahoo.com; Iswanto, Priyo Tri, E-mail: priyatri@yahoo.com; Jatisukamto, Gaguk, E-mail: gagukjtsk@yahoo.co.id [Mechanical and Industrial Engineering Department, Gadjah Mada University Jl. Grafika 2, Yogyakarta, 55281 (Indonesia)

2016-03-29

Nitrogen ion implantation time on tungsten thin film deposited on surface of AISI 410 steel has been performed. Tungsten thin film produced by dc magnetron sputtering method was deposited on AISI 410 martensitic stainless steel substrates, and then the nitrogen ions were implanted on tungsten thin film. The objective of this research is to investigate the effects of implantation deposition time on surface roughness, microhardness, specific wear and corrosion rate of nitrogen implanted on tungsten film. Magnetron sputtering process was performed by using plasma gas of argon (Ar) to bombardier tungsten target (W) in a vacuum chamber with a pressure of 7.6 x 10{sup −2} torr, a voltage of 300 V, a sputter current of 80 mA for sputtered time of 10 minutes. Nitrogen implantation on tungsten film was done with an initial pressure of 3x10{sup −6} mbar, a fluence of 2 x 10{sup 17} ions/cm{sup 2}, an energy of 100 keV and implantation deposition times of 0, 20, 30 and 40 minutes. The surface roughness, microhardness, specific wear and corrosion rate of the films were evaluated by surfcorder test, Vickers microhardness test, wear test and potentiostat (galvanostat) test respectively. The results show that the nitrogen ions implanted deposition time on tungsten film can modify the surface roughness, microhardness, specific wear and corrosion rate. The minimum surface roughness, specific wear and corrosion rate can be obtained for implantation time of 20 minutes and the maximum microhardness of the film is 329 VHN (Vickers Hardness Number) for implantation time of 30 minutes. The specific wear and corrosion rate of the film depend directly on the surface roughness.

Response of temperature and density profiles to heat deposition profile and its impact on global scaling in LHD

International Nuclear Information System (INIS)

Yamada, H.; Murakami, S.; Yamazaki, K.

2002-01-01

Energy confinement and heat transport of net current-free NBI-heated plasmas in the Large Helical Device (LHD) are discussed with an emphasis on density dependence. Although the apparent density dependence of the energy confinement time has been demonstrated in a wide parameter range in LHD, the loss of this dependence has been observed in the high density regime under the specific condition. Broad heat deposition due to off-axis alignment and shallow penetration of neutral beams degrades the global energy confinement while the local heat transport maintains a clear temperature dependence lying between Bohm and gyro-Bohm characteristics. The central heat deposition inclines towards an intrinsic density dependence like τ E ∝(n-bar e /P) 0.6 from the saturated state. The broadening of the temperature profile due to the broad heat deposition profile contrasts with the invariant property which has observed widely as profile consistency and stiffness in tokamak experiments. (author)

Response of temperature and density profiles to heat deposition profile and its impact on global scaling in LHD

International Nuclear Information System (INIS)

Yamada, H.; Murakami, S.; Yamazaki, K.

2003-01-01

Energy confinement and heat transport of net current-free NBI-heated plasmas in the Large Helical Device (LHD) are discussed with an emphasis on density dependence. Although the apparent density dependence of the energy confinement time has been demonstrated in a wide parameter range in LHD, the loss of this dependence has been observed in the high density regime under the specific condition. Broad heat deposition due to off-axis alignment and shallow penetration of neutral beams degrades the global energy confinement while the local heat transport maintains a clear temperature dependence lying between Bohm and gyro-Bohm characteristics. The central heat deposition inclines towards an intrinsic density dependence like τ E ∝(n-bars e /P) 0.6 from the saturated state. The broadening of the temperature profile due to the broad heat deposition profile contrasts with the invariant property which has observed widely as profile consistency and stiffness in tokamak experiments. (author)

Modeling the energy deposition in the Aurora KrF laser amplifier chain

International Nuclear Information System (INIS)

Comly, J.C.; Czuchlewski, S.J.; Greene, D.P.; Hanson, D.E.; Krohn, B.J.; McCown, A.W.

1988-01-01

Monte Carlo calculations model the energy depositions by highly energetic electron beams into the cavities of the four KrF laser amplifiers in the Aurora chain. Deposited energy density distributions are presented and studied as functions of e-beam energy and gas pressure. Results are useful for analyzing small signal gain (SSG) measurements and optimizing deposition in future experiments. 7 refs., 7 figs., 1 tab

Energy deposition of heavy ions in the regime of strong beam-plasma correlations.

Science.gov (United States)

Gericke, D O; Schlanges, M

2003-03-01

The energy loss of highly charged ions in dense plasmas is investigated. The applied model includes strong beam-plasma correlation via a quantum T-matrix treatment of the cross sections. Dynamic screening effects are modeled by using a Debye-like potential with a velocity dependent screening length that guarantees the known low and high beam velocity limits. It is shown that this phenomenological model is in good agreement with simulation data up to very high beam-plasma coupling. An analysis of the stopping process shows considerably longer ranges and a less localized energy deposition if strong coupling is treated properly.

Simulation of the fluctuations of energy and charge deposited during e-beam exposure

International Nuclear Information System (INIS)

Borisov, S. S.; Zaitsev, S. I.; Grachev, E. A.

2007-01-01

The stochastic nature of an energy and charge deposition process is examined using a model based on discrete loss approximation (DLA). Deposited energy deviations computed using the continuous slowing down approximation (CSDA) and DLA are compared. It is shown that CSDA underestimates fluctuations in deposited energy

Multicomponent Time-Dependent Density Functional Theory: Proton and Electron Excitation Energies.

Science.gov (United States)

Yang, Yang; Culpitt, Tanner; Hammes-Schiffer, Sharon

2018-04-05

The quantum mechanical treatment of both electrons and protons in the calculation of excited state properties is critical for describing nonadiabatic processes such as photoinduced proton-coupled electron transfer. Multicomponent density functional theory enables the consistent quantum mechanical treatment of more than one type of particle and has been implemented previously for studying ground state molecular properties within the nuclear-electronic orbital (NEO) framework, where all electrons and specified protons are treated quantum mechanically. To enable the study of excited state molecular properties, herein the linear response multicomponent time-dependent density functional theory (TDDFT) is derived and implemented within the NEO framework. Initial applications to FHF - and HCN illustrate that NEO-TDDFT provides accurate proton and electron excitation energies within a single calculation. As its computational cost is similar to that of conventional electronic TDDFT, the NEO-TDDFT approach is promising for diverse applications, particularly nonadiabatic proton transfer reactions, which may exhibit mixed electron-proton vibronic excitations.

Topography and surface free energy of DPPC layers deposited on a glass, mica, or PMMA support.

Science.gov (United States)

Jurak, Malgorzata; Chibowski, Emil

2006-08-15

An investigation of energetic properties of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) layers deposited on glass, mica, and PMMA (poly(methyl methacrylate)) surfaces was carried out by means of contact angles measurements (advancing and receding) for three probe liquids (diiodomethane, water, and formamide). DPPC was deposited on the surfaces from water (on glass and mica) or methanol (on PMMA) solutions. The topography of the tested surfaces was determined with a help of scanning electron microscopy (SEM) and atomic force microscopy (AFM). Using the measured contact angles, the total apparent surface free energy and its components of the studied layers were determined from van Oss et al.'s (Lifshitz-van der Waals and acid-base components, LWAB) and contact angle hysteresis (CAH) approaches. It allowed us to learn about changes in the surface free energy of the layers (hydrophobicity/hydrophilicity) depending on their number and kind of support. It was found that the changes in the energy greatly depended on the surface properties of the substrate as well as the statistical number of monolayers of DPPC. However, principal changes took place for first three monolayers.

Investigation on the correlation between energy deposition and clustered DNA damage induced by low-energy electrons.

Science.gov (United States)

Liu, Wei; Tan, Zhenyu; Zhang, Liming; Champion, Christophe

2018-05-01

This study presents the correlation between energy deposition and clustered DNA damage, based on a Monte Carlo simulation of the spectrum of direct DNA damage induced by low-energy electrons including the dissociative electron attachment. Clustered DNA damage is classified as simple and complex in terms of the combination of single-strand breaks (SSBs) or double-strand breaks (DSBs) and adjacent base damage (BD). The results show that the energy depositions associated with about 90% of total clustered DNA damage are below 150 eV. The simple clustered DNA damage, which is constituted of the combination of SSBs and adjacent BD, is dominant, accounting for 90% of all clustered DNA damage, and the spectra of the energy depositions correlating with them are similar for different primary energies. One type of simple clustered DNA damage is the combination of a SSB and 1-5 BD, which is denoted as SSB + BD. The average contribution of SSB + BD to total simple clustered DNA damage reaches up to about 84% for the considered primary energies. In all forms of SSB + BD, the SSB + BD including only one base damage is dominant (above 80%). In addition, for the considered primary energies, there is no obvious difference between the average energy depositions for a fixed complexity of SSB + BD determined by the number of base damage, but average energy depositions increase with the complexity of SSB + BD. In the complex clustered DNA damage constituted by the combination of DSBs and BD around them, a relatively simple type is a DSB combining adjacent BD, marked as DSB + BD, and it is of substantial contribution (on average up to about 82%). The spectrum of DSB + BD is given mainly by the DSB in combination with different numbers of base damage, from 1 to 5. For the considered primary energies, the DSB combined with only one base damage contributes about 83% of total DSB + BD, and the average energy deposition is about 106 eV. However, the

Measurement and Prediction of Time-independent and Time-dependent Rheological Behavior of Waxy Crude Oil

OpenAIRE

Yavar Karimi; Ali Reza Solaimany Nazar

2017-01-01

Wax deposition phenomenon changes the rheological behavior of waxy crude oil completely. In the current work, the rheological time-dependent and time-independent behaviors of waxy crude oil samples are studied and flow curve and compliance function are measured for the oil samples with various wax contents at different temperatures. A decrease in temperature and an increase in wax content lead to an increase in the viscosity and yield stress but a significant drop in compliance function. A mo...

Ion implantation range and energy deposition codes COREL, RASE4, and DAMG2

International Nuclear Information System (INIS)

Brice, D.K.

1977-07-01

The FORTRAN codes COREL, RASE4 and DAMG2 can be used to calculate quantities associated with ion implantation range and energy deposition distributions within an amorphous target, or for ions incident far from low index directions and planes in crystalline targets. RASE4 calculates the projected range, R/sub p/, the root mean square spread in the projected range, ΔR/sub p/, and the root mean square spread of the distribution perpendicular to the projected range ΔR/sub perpendicular to/. These parameters are calculated as a function of incident ion energy, E, and the instantaneous energy of the ion, E'. They are sufficient to determine the three dimensional spatial distribution of the ions in the target in the Gaussian approximation when the depth distribution is independent of the lateral distribution. RASE4 can perform these calculations for targets having up to four different component atomic species. The code COREL is a short, economical version of RASE4 which calculates the range and straggling variables for E' = 0. Its primary use in the present package is to provide the average range and straggling variables for recoiling target atoms which are created by the incident ion. This information is used by RASE4 in calculating the redistribution of deposited energy by the target atom recoils. The code DAMG2 uses the output from RASE4 to calculate the depth distribution of energy deposition into either atomic processes or electronic processes. With other input DAMG2 can be used to calculate the depth distribution of any energy dependent interaction between the incident ions and target atoms. This report documents the basic theory behind COREL, RASE4 and DAMG2, including a description of codes, listings, and complete instructions for using the codes, and their limitations

Time-dependent Fracture Behaviour of Polyampholyte Hydrogels

Science.gov (United States)

Sun, Tao Lin; Luo, Feng; Nakajima, Tasuku; Kurokawa, Takayuki; Gong, Jian Ping

Recently, we report that polyampholytes, polymers bearing randomly dispersed cationic and anionic repeat groups, form tough and self-healing hydrogels with excellent multiple mechanical functions. The randomness makes ionic bonds with a wide distribution of strength, via inter and intra chain complexation. As the breaking and reforming of ionic bonds are time dependent, the hydrogels exhibit rate dependent mechanical behaviour. We systematically studied the tearing energy by tearing test with various tearing velocity under different temperature, and the linear viscoelastic behaviour over a wide range of frequency and temperature. Results have shown that the tearing energy markedly increase with the crack velocity and decrease with the measured temperature. In accordance with the prediction of Williams, Landel, and Ferry (WLF) rate-temperature equivalence, a master curve of tearing energy dependence of crack velocity can be well constructed using the same shift factor from the linear viscoelastic data. The scaling relation of tearing energy as a function of crack velocity can be predicted well by the rheological data according to the developed linear fracture mechanics.

50 CFR 259.34 - Minimum and maximum deposits; maximum time to deposit.

Science.gov (United States)

2010-10-01

... B objective. A time longer than 10 years, either by original scheduling or by subsequent extension... OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE AID TO FISHERIES CAPITAL CONSTRUCTION FUND...) Minimum annual deposit. The minimum annual (based on each party's taxable year) deposit required by the...

How Parallel Are Excited State Potential Energy Surfaces from Time-Independent and Time-Dependent DFT? A BODIPY Dye Case Study.

Science.gov (United States)

Komoto, Keenan T; Kowalczyk, Tim

2016-10-06

To support the development and characterization of chromophores with targeted photophysical properties, excited-state electronic structure calculations should rapidly and accurately predict how derivatization of a chromophore will affect its excitation and emission energies. This paper examines whether a time-independent excited-state density functional theory (DFT) approach meets this need through a case study of BODIPY chromophore photophysics. A restricted open-shell Kohn-Sham (ROKS) treatment of the S 1 excited state of BODIPY dyes is contrasted with linear-response time-dependent density functional theory (TDDFT). Vertical excitation energies predicted by the two approaches are remarkably different due to overestimation by TDDFT and underestimation by ROKS relative to experiment. Overall, ROKS with a standard hybrid functional provides the more accurate description of the S 1 excited state of BODIPY dyes, but excitation energies computed by the two methods are strongly correlated. The two approaches also make similar predictions of shifts in the excitation energy upon functionalization of the chromophore. TDDFT and ROKS models of the S 1 potential energy surface are then examined in detail for a representative BODIPY dye through molecular dynamics sampling on both model surfaces. We identify the most significant differences in the sampled surfaces and analyze these differences along selected normal modes. Differences between ROKS and TDDFT descriptions of the S 1 potential energy surface for this BODIPY derivative highlight the continuing need for validation of widely used approximations in excited state DFT through experimental benchmarking and comparison to ab initio reference data.

Self-energy renormalization for inhomogeneous nonequilibrium systems and field expansion via complete set of time-dependent wavefunctions

Science.gov (United States)

Kuwahara, Y.; Nakamura, Y.; Yamanaka, Y.

2018-04-01

The way to determine the renormalized energy of inhomogeneous systems of a quantum field under an external potential is established for both equilibrium and nonequilibrium scenarios based on thermo field dynamics. The key step is to find an extension of the on-shell concept valid in homogeneous case. In the nonequilibrium case, we expand the field operator by time-dependent wavefunctions that are solutions of the appropriately chosen differential equation, synchronizing with temporal change of thermal situation, and the quantum transport equation is derived from the renormalization procedure. Through numerical calculations of a triple-well model with a reservoir, we show that the number distribution and the time-dependent wavefunctions are relaxed consistently to the correct equilibrium forms at the long-term limit.

PRISM -- A tool for modelling proton energy deposition in semiconductor materials

International Nuclear Information System (INIS)

Oldfield, M.K.; Underwood, C.I.

1996-01-01

This paper presents a description of, and test results from, a new PC based software simulation tool PRISM (Protons in Semiconductor Materials). The model describes proton energy deposition in complex 3D sensitive volumes of semiconductor materials. PRISM is suitable for simulating energy deposition in surface-barrier detectors and semiconductor memory devices, the latter being susceptible to Single-Event Upset (SEU) and Multiple-Bit Upset (MBU). The design methodology on which PRISM is based, together with the techniques used to simulate ion transport and energy deposition, are described. Preliminary test results used to analyze the PRISM model are presented

Relativistic time-dependent Fermion-mass renormalization using statistical regularization

Science.gov (United States)

Kutnink, Timothy; McMurray, Christian; Santrach, Amelia; Hockett, Sarah; Barcus, Scott; Petridis, Athanasios

2017-09-01

The time-dependent electromagnetically self-coupled Dirac equation is solved numerically by means of the staggered-leap-frog algorithm with reflecting boundary conditions. The stability region of the method versus the interaction strength and the spatial-grid size over time-step ratio is established. The expectation values of several dynamic operators are then evaluated as functions of time. These include the fermion and electromagnetic energies and the fermion dynamic mass. There is a characteristic, non-exponential, oscillatory dependence leading to asymptotic constants of these expectation values. In the case of the fermion mass this amounts to renormalization. The dependence of the expectation values on the spatial-grid size is evaluated in detail. Furthermore, the contribution of positive and negative energy states to the asymptotic values and the gauge fields is analyzed. Statistical regularization, employing a canonical ensemble whose temperature is the inverse of the grid size, is used to remove the grid-size and momentum-dependence and produce a finite result in the continuum limit.

Temperature dependence of grain boundary free energy and elastic constants

International Nuclear Information System (INIS)

Foiles, Stephen M.

2010-01-01

This work explores the suggestion that the temperature dependence of the grain boundary free energy can be estimated from the temperature dependence of the elastic constants. The temperature-dependent elastic constants and free energy of a symmetric Σ79 tilt boundary are computed for an embedded atom method model of Ni. The grain boundary free energy scales with the product of the shear modulus times the lattice constant for temperatures up to about 0.75 the melting temperature.

Exactly solvable energy-dependent potentials

International Nuclear Information System (INIS)

Garcia-Martinez, J.; Garcia-Ravelo, J.; Pena, J.J.; Schulze-Halberg, A.

2009-01-01

We introduce a method for constructing exactly-solvable Schroedinger equations with energy-dependent potentials. Our method is based on converting a general linear differential equation of second order into a Schroedinger equation with energy-dependent potential. Particular examples presented here include harmonic oscillator, Coulomb and Morse potentials with various types of energy dependence.

The Time-Dependent Chemistry of Cometary Debris in the Solar Corona

Science.gov (United States)

Pesnell, W. D.; Bryans, P.

2015-01-01

Recent improvements in solar observations have greatly progressed the study of sungrazing comets. They can now be imaged along the entirety of their perihelion passage through the solar atmosphere, revealing details of their composition and structure not measurable through previous observations in the less volatile region of the orbit further from the solar surface. Such comets are also unique probes of the solar atmosphere. The debris deposited by sungrazers is rapidly ionized and subsequently influenced by the ambient magnetic field. Measuring the spectral signature of the deposited material highlights the topology of the magnetic field and can reveal plasma parameters such as the electron temperature and density. Recovering these variables from the observable data requires a model of the interaction of the cometary species with the atmosphere through which they pass. The present paper offers such a model by considering the time-dependent chemistry of sublimated cometary species as they interact with the solar radiation field and coronal plasma. We expand on a previous simplified model by considering the fully time-dependent solutions of the emitting species' densities. To compare with observations, we consider a spherically symmetric expansion of the sublimated material into the corona and convert the time-dependent ion densities to radial profiles. Using emissivities from the CHIANTI database and plasma parameters derived from a magnetohydrodynamic simulation leads to a spatially dependent emission spectrum that can be directly compared with observations. We find our simulated spectra to be consistent with observation.

Time-dependent shock acceleration of energetic electrons including synchrotron losses

International Nuclear Information System (INIS)

Fritz, K.; Webb, G.M.

1990-01-01

The present investigation of the time-dependent particle acceleration problem in strong shocks, including synchrotron radiation losses, solves the transport equation analytically by means of Laplace transforms. The particle distribution thus obtained is then transformed numerically into real space for the cases of continuous and impulsive injections of particles at the shock. While in the continuous case the steady-state spectrum undergoes evolution, impulsive injection is noted to yield such unpredicted features as a pile-up of high-energy particles or a steep power-law with time-dependent spectral index. The time-dependent calculations reveal varying spectral shapes and more complex features for the higher energies which may be useful in the interpretation of outburst spectra. 33 refs

A time-dependent search for high-energy neutrinos from bright GRBs with ANTARES

Directory of Open Access Journals (Sweden)

Celli Silvia

2017-01-01

Full Text Available Astrophysical point-like neutrino sources, like Gamma-Ray Bursts (GRBs, are one of the main targets for neutrino telescopes, since they are among the best candidates for Ultra-High-Energy Cosmic Ray (UHECR acceleration. From the interaction between the accelerated protons and the intense radiation fields of the source jet, charged mesons are produced, which then decay into neutrinos. The methods and the results of a search for high-energy neutrinos in spatial and temporal correlation with the detected gamma-ray emission are presented for four bright GRBs observed between 2008 and 2013: a time-dependent analysis, optimised for each flare of the selected bursts, is performed to predict detailed neutrino spectra. The internal shock scenario of the fireball model is investigated, relying on the neutrino spectra computed through the numerical code NeuCosmA. The analysis is optimized on a per burst basis, through the maximization of the signal discovery probability. Since no events in ANTARES data passed the optimised cuts, 90% C.L. upper limits are derived on the expected neutrino fluences.

Fossil fuel energy resources of Ethiopia: Coal deposits

Energy Technology Data Exchange (ETDEWEB)

Wolela, Ahmed [Department of Petroleum Operations, Ministry of Mines and Energy, Kotebe Branch Office, P. O. Box-486, Addis Ababa (Ethiopia)

2007-11-22

The gravity of Ethiopian energy problem has initiated studies to explore various energy resources in Ethiopia, one among this is the exploration for coal resources. Studies confirmed the presence of coal deposits in the country. The coal-bearing sediments are distributed in the Inter-Trappean and Pre-Trap volcanic geological settings, and deposited in fluvio-lacustrine and paludal environments in grabens and half-grabens formed by a NNE-SSW and NNW-SSE fault systems. Most significant coal deposits are found in the Inter-Trappean geological setting. The coal and coal-bearing sediments reach a maximum thickness of 4 m and 300 m, respectively. The best coal deposits were hosted in sandstone-coal-shale and mudstone-coal-shale facies. The coal formations of Ethiopia are quite unique in that they are neither comparable to the coal measures of the Permo-Carboniferous Karroo Formation nor to the Late Devonian-Carboniferous of North America or Northwestern Europe. Proximate analysis and calorific value data indicated that the Ethiopian coals fall under lignite to high volatile bituminous coal, and genetically are classified under humic, sapropelic and mixed coal. Vitrinite reflectance studies confirmed 0.3-0.64% Ro values for the studied coals. Palynology studies confirmed that the Ethiopian coal-bearing sediments range in age from Eocene to Miocene. A total of about 297 Mt of coal reserve registered in the country. The coal reserve of the country can be considered as an important alternative source of energy. (author)

Role of temperature and energy density in the pulsed laser deposition of zirconium oxide thin film

International Nuclear Information System (INIS)

Mittra, Joy; Abraham, G.J.; Viswanadham, C.S.; Kulkarni, U.D.; Dey, G.K.

2011-01-01

Present work brings out the effects of energy density and substrate temperature on pulsed laser deposition of zirconium oxide thin film on Zr-base alloy substrates. The ablation of sintered zirconia has been carried out using a KrF excimer laser having 30 ns pulse width and 600 mJ energy at source at 10 Hz repetition rate. To comprehend effects of these parameters on the synthesized thin film, pure zirconia substrate has been ablated at two different energy densities, 2 J.cm -2 and 5 J.cm -2 , keeping the substrate at 300 K, 573 K and 873 K, respectively. After visual observation, deposited thin films have been examined using Raman Spectroscopy (RS) and X-ray Photo-electron Spectroscopy (XPS). It has been found that the oxide deposited at 300 K temperature does not show good adherence with the substrate and deteriorates further with the reduction in energy density of the incident laser. The oxide films, deposited at 573 K and 873 K, have been found to be adherent with the substrate and appear lustrous black. These indicate that the threshold for adherence of the zirconia film on the Zr-base alloy substrate lies in between 300 K and 573 K. Analysis of Raman spectra has indicated that thin films of zirconia, deposited using pulsed laser, on the Zr-base metallic substrate are initially in amorphous state. Experimental evidence has indicated a strong link among the degree of crystallinity of the deposited oxide film, the substrate temperature and the energy density. It also has shown that the crystallization of the oxide film is dependent on the substrate temperature and the duration of holding at high temperature. The O:Zr ratios of the films, analyzed from the XPS data, have been found to be close to but less than 2. This appears to explain the reason for the transformation of amorphous oxide into monoclinic and tetragonal phases, below 573 K, and not into cubic phase, which is reported to be more oxygen deficient. (author)

Time-dependent weak values and their intrinsic phases of evolution

International Nuclear Information System (INIS)

Parks, A D

2008-01-01

The equation of motion for a time-dependent weak value of a quantum-mechanical observable is known to contain a complex valued energy factor (the weak energy of evolution) that is defined by the dynamics of the pre-selected and post-selected states which specify the observable's weak value. In this paper, the mechanism responsible for the creation of this energy is identified and it is shown that the cumulative effect over time of this energy is manifested as dynamical phases and pure geometric phases (the intrinsic phases of evolution) which govern the evolution of the weak value during its measurement process. These phases are simply related to a Pancharatnam phase and Fubini-Study metric distance defined by the Hilbert space evolution of the associated pre-selected and post-selected states. A characterization of time-dependent weak value evolution as Pancharatnam phase angle rotations and Fubini-Study distance scalings of a vector in the Argand plane is discussed as an application of this relationship. The theory of weak values is also reviewed and simple 'gedanken experiments' are used to illustrate both the time-independent and the time-dependent versions of the theory. It is noted that the direct experimental observation of the weak energy of evolution would strongly support the time-symmetric paradigm of quantum mechanics and it is suggested that weak value equations of motion represent a new category of nonlocal equations of motion

The energy deposition of slowing down particles in heterogeneous media

International Nuclear Information System (INIS)

Prinja, A.K.; Williams, M.M.R.

1980-01-01

Energy deposition by atomic particles in adjacent semi-infinite, amorphous media is described using the forward form of the Boltzmann transport equation. A transport approximation to the scattering kernel, developed elsewhere, incorporating realistic energy transfer is employed to assess the validity of the commonly used isotropic-scattering and straight-ahead approximations. Results are presented for integral energy deposition rates due to a plane, isotropic and monoenergetic source in one half-space for a range of mass ratios between 0.1 and 5.0. Integral profiles for infinite and semi-infinite media are considered and the influence of reflection for different mass ratios is evaluated. The dissimilar scattering properties of the two media induce a discontinuity at the interface in the energy deposition rate the magnitude of which is sensitive to the source position relative to the interface. A comprehensive evaluation of the total energy deposited in the source free medium is presented for a range of mass ratios and source positions. An interesting minimum occurs for off-interface source locations as a function of the source-medium mass ratio, the position of which varies with the source position but is insensitive to the other mass ratio. As a special case, energy reflection and escape coefficients for semi-infinite media are obtained which demonstrates that the effect of a vacuum interface is insignificant for deep source locations except for large mass ratios when reflection becomes dominant. (author)

Is there dependence and systemic risk between oil and renewable energy stock prices?

International Nuclear Information System (INIS)

Reboredo, Juan C.

2015-01-01

We study systemic risk and dependence between oil and renewable energy markets using copulas to characterize the dependence structure and to compute the conditional value-at-risk as a measure of systemic risk. We found significant time-varying average and symmetric tail dependence between oil returns and several global and sectoral renewable energy indices. Our evidence on systemic risk indicates that oil price dynamics significantly contributes around 30% to downside and upside risk of renewable energy companies. These results have important implications for risk management and renewable energy policies. - Highlights: • We study systemic risk and dependence between oil and renewable energy markets. • Dependence and conditional value-at-risk is obtained through copulas. • Oil and renewable energy displayed time-varying average and symmetric tail dependence. • Oil price contribution to the downside and upside risks of renewable energy companies was around 30%

Depth determination of low-energy photon emitter deposits in tissue by means of high-resolution X-ray spectrometry

International Nuclear Information System (INIS)

Schlueter, W.

1982-01-01

A method has been developed for ascertaining the depth of low-energy photon emitters deposited in wounds. It is based on the determination of the energy-dependent absorption of the emitted photons by the tissue separating source and detector. The method is applicable to counting for low-energy photon-emitting nuclides that can be characterized by more than one quantum energy. Attenuation coefficients were given for lard, beef, and five tissue- equivalent materials. For spectrometry, a planar Ge(Li) detector proved most suitable. (author)

Positive solution of a time and energy dependent neutron transport problem

International Nuclear Information System (INIS)

Pao, C.V.

1975-01-01

A constructive method is given for the determination of a solution and an existence--uniqueness theorem for some nonlinear time and energy dependent neutron transport problems, including the linear transport system. The geometry of the medium under consideration is allowed to be either bounded or unbounded which includes the geometry of a finite or infinite cylinder, a half-space and the whole space R/subm/ (m=1,2,center-dotcenter-dotcenter-dot). Our approach to the problem is by successive approximation which leads to various recursion formulas for the approximations in terms of explicit integrations. It is shown under some Lipschitz conditions on the nonlinear functions, which describe the process of neutrons absorption, fission, and scattering, that the sequence of approximations converges to a unique positive solution. Since these conditions are satisfied by the linear transport equation, all the results for the nonlinear system are valid for the linear transport problem. In the general nonlinear problem, the existence of both local and global solutions are discussed, and an iterative process for the construction of the solution is given

Germanium nanoparticles grown at different deposition times for memory device applications

International Nuclear Information System (INIS)

Mederos, M.; Mestanza, S.N.M.; Lang, R.; Doi, I.; Diniz, J.A.

2016-01-01

In the present work, circular Metal-Oxide-Semiconductor capacitors with 200 μm of diameter and germanium (Ge) nanoparticles (NPs) embedded in the gate oxide are studied for memory applications. Optimal process parameters are investigated for Ge NPs growing by low pressure chemical vapor deposition at different deposition times. Photoluminescence measurements showed room-temperature size-dependent green-red region bands attributed to quantum confinement effects present in the NPs. High-frequency capacitance versus voltage measurements demonstrated the memory effects on the MOS structures due to the presence of Ge NPs in the gate oxide acting as discrete floating gates. Current versus voltage measurements confirmed the Fowler-Nordheim tunneling as the programming mechanism of the devices. - Highlights: • Ge nanoparticles with high density and uniforms sizes were obtained by LPCVD. • Room-temperature size-dependent bands of photoluminescence were observed. • MOS capacitors with Ge nanoparticles embedded in the oxide were fabricated. • Ge nanoparticles are the main responsible for the memory properties in the devices. • Fowler-Nordheim tunneling is the conduction mechanism observed on the devices.

Germanium nanoparticles grown at different deposition times for memory device applications

Energy Technology Data Exchange (ETDEWEB)

Mederos, M., E-mail: melissa.mederos@gmail.com [Center for Semiconductor Components and Nanotechnology (CCSNano), University of Campinas (Unicamp), Rua João Pandia Calógeras 90, Campinas, CEP: 13083-870, São Paulo (Brazil); Mestanza, S.N.M. [Federal University of ABC (UFABC), Rua Santa Adélia 166, Bangu, Santo André, CEP: 09210-170, São Paulo (Brazil); Lang, R. [Institute of Science and Technology, Federal University of São Paulo (UNIFESP), Rua Talim, 330, São José dos Campos, CEP: 12231-280, São Paulo (Brazil); Doi, I.; Diniz, J.A. [Center for Semiconductor Components and Nanotechnology (CCSNano), University of Campinas (Unicamp), Rua João Pandia Calógeras 90, Campinas, CEP: 13083-870, São Paulo (Brazil); School of Electrical and Computer Engineering, University of Campinas (Unicamp), Av. Albert Einstein 400, Campinas, CEP: 13083-852, São Paulo (Brazil)

2016-07-29

In the present work, circular Metal-Oxide-Semiconductor capacitors with 200 μm of diameter and germanium (Ge) nanoparticles (NPs) embedded in the gate oxide are studied for memory applications. Optimal process parameters are investigated for Ge NPs growing by low pressure chemical vapor deposition at different deposition times. Photoluminescence measurements showed room-temperature size-dependent green-red region bands attributed to quantum confinement effects present in the NPs. High-frequency capacitance versus voltage measurements demonstrated the memory effects on the MOS structures due to the presence of Ge NPs in the gate oxide acting as discrete floating gates. Current versus voltage measurements confirmed the Fowler-Nordheim tunneling as the programming mechanism of the devices. - Highlights: • Ge nanoparticles with high density and uniforms sizes were obtained by LPCVD. • Room-temperature size-dependent bands of photoluminescence were observed. • MOS capacitors with Ge nanoparticles embedded in the oxide were fabricated. • Ge nanoparticles are the main responsible for the memory properties in the devices. • Fowler-Nordheim tunneling is the conduction mechanism observed on the devices.

Time dependence of energy spectra of brachytherapy sources and its impact on the half and the tenth value layers

International Nuclear Information System (INIS)

Yue, Ning J.; Chen Zhe; Hearn, Robert A.; Rodgers, Joseph J.; Nath, Ravinder

2009-01-01

Purpose: Several factors including radionuclide purity influence the photon energy spectra from sealed brachytherapy sources. The existence of impurities and trace elements in radioactive materials as well as the substrate and encapsulation may not only alter the spectrum at a given time but also cause change in the spectra as a function of time. The purpose of this study is to utilize a semiempirical formalism, which quantitatively incorporates this time dependence, to calculate and evaluate the shielding requirement impacts introduced by this time dependence for a 103 Pd source. Methods: The formalism was used to calculate the NthVL thicknesses in lead for a 103 Pd model 200 seed. Prior to 2005, the 103 Pd in this source was purified to a level better than 0.006% of the total 103 Pd activity, the key trace impurity consisting of 65 Zn. Because 65 Zn emits higher energy photons and has a much longer half-life of 244 days compared to 103 Pd, its presence in 103 Pd seeds led to a time dependence of the photon spectrum and other related physical quantities. This study focuses on the time dependence of the NthVL and the analysis of the corresponding shielding requirements. Results: The results indicate that the first HVL and the first TVL in lead steadily increased with time for about 200 days and then reached a plateau. The increases at plateau were more than 1000 times compared to the corresponding values on the zeroth day. The second and third TVLs in lead reached their plateaus in about 100 and 60 days, respectively, and the increases were about 19 and 2.33 times the corresponding values on the zeroth day, respectively. All the TVLs demonstrated a similar time dependence pattern, with substantial increases and eventual approach to a plateau. Conclusions: The authors conclude that the time dependence of the emitted photon spectra from brachytherapy sources can introduce substantial variations in the values of the NthVL with time if certain impurities are present

Measurement of energy deposition near high energy, heavy ion tracks. Progress report, December 1982-April 1985

Energy Technology Data Exchange (ETDEWEB)

Metting, N.F.; Braby, L.A.; Rossi, H.H.; Kliauga, P.J.; Howard, J.; Schimmerling, W.; Wong, M.; Rapkin, M.

1986-08-01

The microscopic spatial distribution of energy deposition in irradiated tissue plays a significant role in the final biological effect produced. Therefore, it is important to have accurate microdosimetric spectra of radiation fields used for radiobiology and radiotherapy. The experiments desribed here were designed to measure the distributions of energy deposition around high energy heavy ion tracks generated at Lawrence Berkeley Laboratory's Bevalac Biomedical Facility. A small proportional counter mounted in a large (0.6 by 2.5 m) vacuum chamber was used to measure energy deposition distributions as a function of the distance between detector and primary ion track. The microdosimetric distributions for a homogeneous radiation field were then calculated by integrating over radial distance. This thesis discusses the rationale of the experimental design and the analysis of measurements on 600 MeV/amu iron tracks. 53 refs., 19 figs.

Measurement of energy deposition near high energy, heavy ion tracks. Progress report, December 1982-April 1985

International Nuclear Information System (INIS)

Metting, N.F.; Braby, L.A.; Rossi, H.H.; Kliauga, P.J.; Howard, J.; Schimmerling, W.; Wong, M.; Rapkin, M.

1986-08-01

The microscopic spatial distribution of energy deposition in irradiated tissue plays a significant role in the final biological effect produced. Therefore, it is important to have accurate microdosimetric spectra of radiation fields used for radiobiology and radiotherapy. The experiments desribed here were designed to measure the distributions of energy deposition around high energy heavy ion tracks generated at Lawrence Berkeley Laboratory's Bevalac Biomedical Facility. A small proportional counter mounted in a large (0.6 by 2.5 m) vacuum chamber was used to measure energy deposition distributions as a function of the distance between detector and primary ion track. The microdosimetric distributions for a homogeneous radiation field were then calculated by integrating over radial distance. This thesis discusses the rationale of the experimental design and the analysis of measurements on 600 MeV/amu iron tracks. 53 refs., 19 figs

Non-local energy deposition: A problem in regional RF hyperthermia

International Nuclear Information System (INIS)

Hagmann, M.J.; Levin, R.L.

1984-01-01

As the frequency is decreased below 1 GHz, RF applicators can cause deep heating of tissues. However, there is a concomitant problem in that significant energy deposition may occur well beyond the dimensions of the applicator. The BSD Medical Corporation has described to the authors tests with a phantom manequin in which SAR in the neck was significantly greater than that in the abdomen when an Annular Phased Array System (APAS) was positioned for abdominal heating. The authors have obtained numerical solutions for the SAR distribution in a 180-cell inhomogeneous block model of man subjected to r-f irradiation approximating that emanating from various applicators. The solutions agree with the reports of BSD that significant heating in the neck, inner thighs, and back will occur with an abdominally-placed APAS. They suggest that a similar problem will occur with a helical-coil or other applicator for which the electric field is predominantly parallel to the axis of the body. Typically, 70% or more of the total energy will be deposited outside the bounds of an axial applicator when it is placed around the chest or abdomen. The problem is most severe at frequencies for which body parts such as the arm or head may resonate. In such cases, over 90% of the energy may be deposited outside the bounds of applicator. The problem of non-local energy deposition appears to be substantially reduced for non-axial applicators. If the arm extends outward from the side of the body, an axial applicator around it will cause negligible energy deposition in the rest of the body

Optimization of the LHC interaction region with respect to beam-induced energy deposition

International Nuclear Information System (INIS)

Mokhov, N.V.; Strait, J.B.

1996-06-01

Energy deposition in the superconducting magnets by particles from p- p collisions is a significant challenge for the design of the LHC high luminosity insertions. We have studies the dependence of the energy deposition on the apertures and strengths of insertion magnets and on the placement of absorbers in front of and within the quadrupoles. Monte Carlo simulations were made using the code DTUJET to generate 7x7 TeV p-p events and the code MARS to follow hadronic and electromagnetic cascades induced in the insertion components. The 3D geometry and magnetic field descriptions of the LHC-4.1 lattice were used. With a quadrupole coil aperture ≥70 mm, absorbers can be placed within the magnet bore which reduce the peak power density, at full luminosity, below 0.5 mW/g, a level that should allow the magnets to operate at their design field. The total heat load can be removed by a cooling system similar to that used in the main magnets

Beryllium-7 and 210Pb atmospheric deposition measured in moss and dependence on cumulative precipitation

International Nuclear Information System (INIS)

Krmar, M.; Mihailović, D.T.; Arsenić, I.; Radnović, D.; Pap, I.

2016-01-01

This paper focuses on analysis of the time series of 7 Be and 210 Pb activity measured in moss, and the amount, as well as duration of precipitation, to gain a better understanding of the possible relationships between airborne radionuclide deposition and precipitation. Here we consider whether the amount of these airborne radionuclides in moss samples is a cumulative measure of radionuclide deposition and decay, and a new approach for analyses of the relationships between precipitation and moss activity concentrations is suggested. Through these analyses it was shown that comparison of cumulative activity measured at one location using moss, normalized by values of cumulative amount or duration of precipitation, showed different regimes of airborne radionuclide deposition. - Graphical abstract: Correlation between cumulative activity of 7 Be and 210 Pb measured in moss samples normalized by the cumulative precipitation. - Highlights: • Use of mosses in measurement of airborne radionuclides deposition was investigated • Prior work indicated 7 Be and 210 Pb activities were not correlated with precipitation • This is unusual since radionuclides moss tissues depends on depositional fluxes. • A new method for study of 7 Be and 210 Pb depositional dynamics was developed • Different seasonal regimes of 7 Be deposition are more noticeable in new technique

Some notes on time dependent Thomas Fermi approximation

International Nuclear Information System (INIS)

Holzwarth, G.

1979-01-01

The successful use of effective density-dependent potentials in static Hartree-Fock calculations for nuclear ground-state properties has led to the question whether it is possible to obtain significant further simplification by approximating also the kinetic energy part of the ground state energy by a functional of the local density alone. The great advantage of such an approach is that its complexity is independent of particle number; the size of the system enters only through parameters, Z and N. The simple 'extended Thomas Fermi' functionals are based on the assumption of a spherically symmetric local Fermi surface throughout the nucleus and they represent the 'liquid drop' part of the static total energy. Given this static formalism which is solved directly for the local density without considering individual particles one might ask for a possible dynamical extension in the same sense as TDHF is a dynamical extension of the static HF approach. The aim of such a Time Dependent Thomas Fermi (TDTF) approximation would be to determine directly the time-dependent local single-particle density from given initial conditions and the single-particle current density without following each particle on its individual orbit

On the measurement of time-dependent quantum phases

International Nuclear Information System (INIS)

Barut, A.O.; Bozic, M.; Klarsfeld, S.; Maric, Z.

1991-11-01

We have evaluated the exact (Pancharatnam) phase differences between the final state l ψ(t) > and various initial states for a spin 1/2-particle in a rotating magnetic field B(t). For the initial states l n; B ef (0) >, which are eigenstates of the spin component along the direction of the initial effective field B ef (0), the exact phase has an energy dependent part, and an energy independent part. It is shown that these states l n; B ef (0) > are cyclic and their corresponding Aharonov-Anandan phases are evaluated. In the adiabatic limit we discuss different choices of time-dependent bases and the relationship between the exact phase, the Born-Fock-Schiff phase and Berry's phase. We propose experiments (neutron) to verify separately the exact and the adiabatic evolution laws, as well as to measure the adiabatic phases associated with different choices of time-dependent basis vectors. (author). 37 refs, 5 figs, 1 tab

Time-dependent--S-matrix Hartree-Fock theory of complex reactions

International Nuclear Information System (INIS)

Griffin, J.J.; Lichtner, P.C.; Dworzecka, M.

1980-01-01

Some limitations of the conventional time-dependent Hartree-Fock method for describing complex reactions are noted, and one particular ubiquitous defect is discussed in detail: the post-breakup spurious cross channel correlations which arise whenever several asymptotic reaction channels must be simultaneously described by a single determinant. A reformulated time-dependent--S-matrix Hartree-Fock theory is proposed, which obviates this difficulty. Axiomatic requirements minimal to assure that the time-dependent--S-matrix Hartree-Fock theory represents an unambiguous and physically interpretable asymptotic reaction theory are utilized to prescribe conditions upon the definition of acceptable asymptotic channels. That definition, in turn, defines the physical range of the time-dependent--S-matrix Hartree-Fock theory to encompass the collisions of mathematically well-defined ''time-dependent Hartree-Fock droplets.'' The physical properties of these objects then circumscribe the content of the Hartree-Fock single determinantal description. If their periodic vibrations occur for continuous ranges of energy then the resulting ''classical'' time-dependent Hartree-Fock droplets are seen to be intrinsically dissipative, and the single determinantal description of their collisions reduces to a ''trajectory'' theory which can describe the masses and relative motions of the fragments but can provide no information about specific asymptotic excited states beyond their constants of motion, or the average properties of the limit, if it exists, of their equilibrization process. If, on the other hand, the periodic vibrations of the time-dependent Hartree-Fock droplets are discrete in energy, then the time-dependent--S-matrix Hartree-Fock theory can describe asymptotically the time-average properties of the whole spectrum of such periodic vibrations

Time-dependent Hartree approximation and time-dependent harmonic oscillator model

International Nuclear Information System (INIS)

Blaizot, J.P.

1982-01-01

We present an analytically soluble model for studying nuclear collective motion within the framework of the time-dependent Hartree (TDH) approximation. The model reduces the TDH equations to the Schroedinger equation of a time-dependent harmonic oscillator. Using canonical transformations and coherent states we derive a few properties of the time-dependent harmonic oscillator which are relevant for applications. We analyse the role of the normal modes in the time evolution of a system governed by TDH equations. We show how these modes couple together due to the anharmonic terms generated by the non-linearity of the theory. (orig.)

Modelling of the energy density deposition profiles of ultrashort laser pulses focused in optical media

International Nuclear Information System (INIS)

Vidal, F; Lavertu, P-L; Bigaouette, N; Moore, F; Brunette, I; Giguere, D; Kieffer, J-C; Olivie, G; Ozaki, T

2007-01-01

The propagation of ultrashort laser pulses in dense optical media is investigated theoretically by solving numerically the nonlinear Schroedinger equation. It is shown that the maximum energy density deposition as a function of the pulse energy presents a well-defined threshold that increases with the pulse duration. As a consequence of plasma defocusing, the maximum energy density deposition is generally smaller and the size of the energy deposition zone is generally larger for shorter pulses. Nevertheless, significant values of the energy density deposition can be obtained near threshold, i.e., at lower energy than for longer pulses

Transmission electron microscopy study of ion energy deposition in gold: evidence for a spike threshold

International Nuclear Information System (INIS)

Ruault, M.O.; Bernas, H.; Chaumont, J.

1978-01-01

Nine different atomic species, from K to Yb, were implanted into gold at energies ranging from 20 to 150 keV. The nature and depth-distribution of the resultant defect clusters were studied by transmission electron microscopy techniques as well as a modification of the '2 1/2-D' stereo technique developed by Mitchell and Bell. The effect of implanted ion dose and sample purity were determined. The cluster depth distributions are in overall agreement with the damage distributions deduced from the energy deposition calculations of Winterbon, Sigmund, and Sanders. The nature of the defect clusters is found to depend on the mass and energy of the incoming ion, in agreement with our previously reported work. These results are suggested to provide evidence for the decisive influence of the deposited energy density on the nature of visible damage. We conclude that it is possible to distinguish between cascade and 'spike' effects, the latter setting in when the average energy per atom in the cascade is approximately 2 eV/atom. All results (obtained -at low doses on pure samples- for a variety of ion species in Au, Al, Cu, W, Mo and Ni) may be related to each other in this way

Measurement of energy deposition distributions produced in cylindrical geometry by irradiation with 15 MeV neutrons

International Nuclear Information System (INIS)

Brandan, M.E.

1979-01-01

Cellular survival experiments have shown that the biological damage induced by radiation depends on the density of energy deposition along the trajectory of the ionizing particle. The quantity L is defined to measure the density of energy transfer along a charged particle's trajectory. It is equal to sigma/l, where sigma is the energy transferred to a medium and l is the path length along which the transfer takes place. L is the stochastic quantity whose mean value is the unrestricted linear energy transfer, L/sub infinity/. Measurements of the distribution of L in a thin medium by secondary charged particles from fast neutron irradiation were undertaken. A counter operating under time coincidence between two coaxial cylindrical detectors was designed and built for this purpose. Secondary charged particles enter a gas proportional counter and deposit some energy sigma. Those particles traversing the chamber along a radial trajectory strike a CsI scintillator. A coincidence between both detectors' signals selects a known path length for these events, namely the radius of the cavity. Measurements of L distributions for l = 1 μm in tissue were obtained for 3 and 15 MeV neutron irradiation of a tissue-equivalent target wall and for 15 MeV neutron irradiation of a graphite wall. Photon events were corrected for by measurements with a Pb target wall and 15 MeV neutron irradiation as well as exposure to a pure photon field. The measured TE wall distributions with 15 MeV neutron bombardment show contributions from protons, α-particles, 9 Be and 12 C recoils. The last three comprise the L distribution for irradiation of the graphite wall. The proton component of the measured L distributions at 3 and 15 MeV was compared to calculated LET distributions

Real time monitoring of filament-assisted chemically vapor deposited diamond by spectroscopic ellipsometry

International Nuclear Information System (INIS)

Yue Cong; An, I.; Vedam, K.; Collins, R.W.; Nguyen, H.V.; Messier, R.

1991-01-01

Spectroscopic ellipsometry over the range 1.5-4.5 eV was applied as a real time probe of the processes occurring in the initial nucleation of thin film diamond by heated-filament assisted chemical vapor deposition. Using both untreated and diamond-polished c-Si substrates, as well as both carburized and uncarburized tungsten filaments, it was possible to separate and characterize competing phenomena, including the increase in surface temperature induced by filament ignition, the formation of carbide layers, contamination of the substrate by tungsten from the filament, annealing of diamond polishing damage, and, finally, diamond nucleation. An accurate measurement of the true temperature of the substrate surface averaged over the top 500 A can be obtained from the energy position of critical points in the c-Si band structure. For diamond deposition, we operated with an initial excess flow of CH 4 to stimulate nucleation. We applied real time feedback and manual control to reduce the CH 4 flow in the first monolayers of deposition. The thickness of diamond and an estimate of its nucleation density can be obtained from real time spectra, and the latter was in good agreement with that obtained from scanning electron microscopy. (orig.)

Energy storage and deposition in a solar flare

Science.gov (United States)

Vorpahl, J. A.

1976-01-01

X-ray pictures of a solar flare taken with the S-056 X-ray telescope aboard Skylab are interpreted in terms of flare energy deposition and storage. The close similarity between calculated magnetic-field lines and the overall structure of the X-ray core is shown to suggest that the flare occurred in an entire arcade of loops. It is found that different X-ray features brightened sequentially as the flare evolved, indicating that some triggering disturbance moved from one side to the other in the flare core. A propagation velocity of 180 to 280 km/s is computed, and it is proposed that the geometry of the loop arcade strongly influenced the propagation of the triggering disturbance as well as the storage and site of the subsequent energy deposition. Some possible physical causes for the sequential X-ray brightening are examined, and a magnetosonic wave is suggested as the triggering disturbance. 'Correct' conditions for energy release are considered

Summary and presentation of the international workshop on beam induced energy deposition (issues, concerns, solutions)

International Nuclear Information System (INIS)

Soundranayagam, R.

1991-11-01

This report discusses: energy deposition and radiation shielding in antriproton source at FNAL; radiation issues/problems at RHIC; radiation damage to polymers; radiation effects on optical fibre in the SSC tunnel; capabilities of the Brookhaven Radiation Effects Facility; the SSC interaction region; the FLUKA code system, modifications, recent extension and experimental verification; energy particle transport calculations and comparisons with experimental data; Los Alamos High Energy Transport code system; MCNP features and applications; intercomparison of Monte Carlo codes designed for simulation of high energy hadronic cascades; event generator, DTUJET-90 and DTUNUC; Preliminary hydrodynamic calculations of beam energy deposition; MESA code calculations of material response to explosive energy deposition; Smooth particle hydrodynamic; hydrodynamic effects and mass depletion phenomena in targets; beam dump: Beam sweeping and spoilers; Design considerations to mitigate effects of accidental beam dump; SSC beam abort and absorbed; beam abort system of SSC options; unconventional scheme for beam spoilers; low β quadrupoles: Energy deposition and radioactivation; beam induces energy deposition in the SSC components; extension of SSC-SR-1033 approach to radioactivation in LHC and SSC detectors; energy deposition in the SSC low-β IR-quads; beam losses and collimation in the LHC; and radiation shielding around scrapers

Venusian extended ejecta deposits as time-stratigraphic markers

Science.gov (United States)

Izenberg, Noam R.

1992-01-01

Use of impact crater ejects at time-stratigraphic markers was established during lunar geologic mapping efforts. The basic premise is that the deposition of impact ejecta, either by itself or mixed with impact-excavated material, is superimposed on a surface. The deposit becomes an observable, mappable unit produced in a single instant in geologic time. Up to two-thirds of Venus craters exhibit extended ejecta deposits. A reconnaissance survey of 336 craters (about 40 percent of the total population) was conducted. About half the craters examined were located in and around the Beta-Atla-Themis region, and half were spread over the western hemisphere of the planet. The survey was conducted using primarily C1-MIDR images. The preliminary survey shows: (1) of the 336 craters, 223 were found to have extended ejecta deposits. This proportion is higher than that found in other Venus crater databases by up to a factor of 2. (2) 53 percent of all extended ejecta craters were unambiguously superimposed on all volcanic and tectonic units. Crater Annia Faustina's associated parabolic ejecta deposit is clearly superimposed on volcanic flows coming from Gula Mons to the west. Parabola material from Faustina has covered the lava flows, smoothing the surface and reducing its specific backscatter cross section. The stratigraphy implies that the parabola material is the youngest observable unit in the region. (3) 12 percent of extended ejecta deposits are superimposed by volcanic materials. Crater Hwangcini has extended ejecta that has been covered by volcanic flows from a dome field to the northwest, implying that the volcanic units were emplaced subsequent to the ejecta deposit and are the youngest units in the locality. (4) It is difficult to determine the stratigraphic relationships of the remaining extended ejecta deposits in SAR at C1-MIDR resolution. Examination of higher resolution images and application of the other Magellan datasets in systematic manner should resolve

Energy deposition profile on ISOLDE Beam Dumps by FLUKA simulations

CERN Document Server

Vlachoudis, V

2014-01-01

In this report an estimation of the energy deposited on the current ISOLDE beam dumps obtained by means of FLUKA simulation code is presented. This is done for both ones GPS and HRS. Some estimations of temperature raise are given based on the assumption of adiabatic increase from energy deposited by the impinging protons. However, the results obtained here in relation to temperature are only a rough estimate. They are meant to be further studied through thermomechanical simulations using the energyprofiles hereby obtained.

Energy deposition model for I-125 photon radiation in water

International Nuclear Information System (INIS)

Fuss, M.C.; Garcia, G.; Munoz, A.; Oller, J.C.; Blanco, F.; Limao-Vieira, P.; Williart, A.; Garcia, G.; Huerga, C.; Tellez, M.

2010-01-01

In this study, an electron-tracking Monte Carlo algorithm developed by us is combined with established photon transport models in order to simulate all primary and secondary particle interactions in water for incident photon radiation. As input parameters for secondary electron interactions, electron scattering cross sections by water molecules and experimental energy loss spectra are used. With this simulation, the resulting energy deposition can be modelled at the molecular level, yielding detailed information about localization and type of single collision events. The experimental emission spectrum of I-125 seeds, as used for radiotherapy of different tumours, was used for studying the energy deposition in water when irradiating with this radionuclide. (authors)

Energy deposition model for I-125 photon radiation in water

Energy Technology Data Exchange (ETDEWEB)

Fuss, M.C.; Garcia, G. [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain); Munoz, A.; Oller, J.C. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Madrid (Spain); Blanco, F. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid (Spain); Limao-Vieira, P. [Laboratorio de Colisoes Atomicas e Moleculares, Departamento de Fisica, CEFITEC, FCT-Universidade Nova de Lisboa, Caparica (Portugal); Williart, A.; Garcia, G. [Departamento de Fisica de los Materiales, Universidad Nacional de Educacion a Distancia, Madrid (Spain); Huerga, C.; Tellez, M. [Hospital Universitario La Paz, Madrid (Spain)

2010-10-15

In this study, an electron-tracking Monte Carlo algorithm developed by us is combined with established photon transport models in order to simulate all primary and secondary particle interactions in water for incident photon radiation. As input parameters for secondary electron interactions, electron scattering cross sections by water molecules and experimental energy loss spectra are used. With this simulation, the resulting energy deposition can be modelled at the molecular level, yielding detailed information about localization and type of single collision events. The experimental emission spectrum of I-125 seeds, as used for radiotherapy of different tumours, was used for studying the energy deposition in water when irradiating with this radionuclide. (authors)

Optical Properties Dependence with Gas Pressure in AlN Films Deposited by Pulsed Laser Ablation

International Nuclear Information System (INIS)

Perez, J A; Riascos, H; Caicedo, J C; Cabrera, G; Yate, L

2011-01-01

AlN films were deposited by pulsed laser deposition technique (PLD) using an Nd: YAG laser (λ = 1064 nm). The films were deposited in a nitrogen atmosphere as working gas; the target was an aluminum high purity (99.99%). The films were deposited with a laser fluence of 7 J/cm2 for 10 minutes on silicon (100) substrates. The substrate temperature was 300 deg. C and the working pressure was varied from 3 mtorr to 11 mtorr. The thickness measured by profilometer was 150 nm for all films. The crystallinity was observed via XRD pattern, the morphology and composition of the films were studied using scanning electron microscopy (SEM) and Energy Dispersive X-ray analysis (EDX), respectively. The optical reflectance spectra and color coordinates of the films were obtained by optical spectral reflectometry technique in the range of 400 cm-1- 900 cm-1 by an Ocean Optics 2000 spectrophotometer. In this work, a clear dependence of the reflectance, dominant wavelength and color purity was found in terms of the applied pressure to the AlN films. A reduction in reflectance of about 55% when the pressure was increased from 3 mtorr to 11 mtorr was observed. This paper deals with the formation of AlN thin films as promising materials for the integration of SAW devices on Si substrates due to their good piezoelectric properties and the possibility of deposition at low temperature compatible with the manufacturing of Si integrated circuits.

Optical Properties Dependence with Gas Pressure in AlN Films Deposited by Pulsed Laser Ablation

Energy Technology Data Exchange (ETDEWEB)

Perez, J A; Riascos, H [Departamento de Fisica, Universidad Tecnologica de Pereira, Grupo plasma Laser y Aplicaciones A.A 097 (Colombia); Caicedo, J C [Grupo pelIculas delgadas, Universidad del Valle, Cali (Colombia); Cabrera, G; Yate, L, E-mail: jcaicedoangulo@gmail.com [Department de Fisica Aplicada i Optica, Universitat de Barcelona, Catalunya (Spain)

2011-01-01

AlN films were deposited by pulsed laser deposition technique (PLD) using an Nd: YAG laser ({lambda} = 1064 nm). The films were deposited in a nitrogen atmosphere as working gas; the target was an aluminum high purity (99.99%). The films were deposited with a laser fluence of 7 J/cm2 for 10 minutes on silicon (100) substrates. The substrate temperature was 300 deg. C and the working pressure was varied from 3 mtorr to 11 mtorr. The thickness measured by profilometer was 150 nm for all films. The crystallinity was observed via XRD pattern, the morphology and composition of the films were studied using scanning electron microscopy (SEM) and Energy Dispersive X-ray analysis (EDX), respectively. The optical reflectance spectra and color coordinates of the films were obtained by optical spectral reflectometry technique in the range of 400 cm-1- 900 cm-1 by an Ocean Optics 2000 spectrophotometer. In this work, a clear dependence of the reflectance, dominant wavelength and color purity was found in terms of the applied pressure to the AlN films. A reduction in reflectance of about 55% when the pressure was increased from 3 mtorr to 11 mtorr was observed. This paper deals with the formation of AlN thin films as promising materials for the integration of SAW devices on Si substrates due to their good piezoelectric properties and the possibility of deposition at low temperature compatible with the manufacturing of Si integrated circuits.

The energy-deposition model. Electron loss of heavy ions in collisions with neutral atoms at low and intermediate energies

International Nuclear Information System (INIS)

Shevelko, V.P.; Litsarev, M.S.; Kato, D.; Tawara, H.

2010-09-01

Single- and multiple-electron loss processes in collisions of heavy many-electron ions (positive and negative) in collisions with neutral atoms at low and intermediate energies are considered using the energy-deposition model. The DEPOSIT computer code, created earlier to calculate electron-loss cross sections at high projectile energies, is extended for low and intermediate energies. A description of a new version of DEPOSIT code is given, and the limits of validity for collision velocity in the model are discussed. Calculated electron-loss cross sections for heavy ions and atoms (N + , Ar + , Xe + , U + , U 28+ , W, W + , Ge - , Au - ), colliding with neutral atoms (He, Ne, Ar, W) are compared with available experimental and theoretical data at energies E > 10 keV/u. It is found that in most cases the agreement between experimental data and the present model is within a factor of 2. Combining results obtained by the DEPOSIT code at low and intermediate energies with those by the LOSS-R code at high energies (relativistic Born approximation), recommended electron-loss cross sections in a wide range of collision energy are presented. (author)

Energy and dose characteristics of ion bombardment during pulsed laser deposition of thin films under pulsed electric field

International Nuclear Information System (INIS)

Fominski, V.Yu.; Nevolin, V.N.; Smurov, I.

2004-01-01

Experiments on pulsed laser deposition of Fe films on Si substrates were performed with the aim to analyze the role of factors determining the formation of an energy spectrum and a dose of ions bombarding the film in strong pulsed electric fields. The amplitude of the high-voltage pulse (-40 kV) applied to the substrate and the laser fluence at the Fe target were fixed during the deposition. Owing to the high laser fluence (8 J/cm 2 ) at a relatively low power (20 mJ), the ionization of the laser plume was high, but the Fe vapor pressure near the substrate was low enough to avoid arcing. Electric signals from a target exposed to laser radiation were measured under different conditions (at different delay times) of application of electric pulses. The Si(100) substrates were analyzed using Rutherford ion backscattering/channeling spectrometry. The ion implantation dose occurred to be the highest if the high-voltage pulse was applied at a moment of time when the ion component of the plume approached the substrate. In this case, the implanted ions had the highest energy determined by the amplitude of the electric pulse. An advance or delay in applying a high-voltage pulse caused the ion dose and energy to decrease. A physical model incorporating three possible modes of ion implantation was proposed for the interpretation of the experimental results. If a laser plume was formed in the external field, ions were accelerated from the front of the dense plasma, and the ion current depended on the gas-dynamic expansion of the plume. The application of a high-voltage pulse, at the instant when the front approached the substrate, maintained the mode that was characteristic of the traditional plasma immersion ion implantation, and the ion current was governed by the dynamics of the plasma sheath in the substrate-to-target gap. In the case of an extremely late application of a high-voltage pulse, ions retained in the entire volume of the experimental chamber (as a result of the

Monolayer phosphorene under time-dependent magnetic field

Science.gov (United States)

Nascimento, J. P. G.; Aguiar, V.; Guedes, I.

2018-02-01

We obtain the exact wave function of a monolayer phosphorene under a low-intensity time-dependent magnetic field using the dynamical invariant method. We calculate the quantum-mechanical energy expectation value and the transition probability for a constant and an oscillatory magnetic field. For the former we observe that the Landau level energy varies linearly with the quantum numbers n and m and the magnetic field intensity B0. No transition takes place. For the latter, we observe that the energy oscillates in time, increasing linearly with the Landau level n and m and nonlinearly with the magnetic field. The (k , l) →(n , m) transitions take place only for l = m. We investigate the (0,0) →(n , 0) and (1 , l) and (2 , l) probability transitions.

Watching excitons move: the time-dependent transition density matrix

Science.gov (United States)

Ullrich, Carsten

2012-02-01

Time-dependent density-functional theory allows one to calculate excitation energies and the associated transition densities in principle exactly. The transition density matrix (TDM) provides additional information on electron-hole localization and coherence of specific excitations of the many-body system. We have extended the TDM concept into the real-time domain in order to visualize the excited-state dynamics in conjugated molecules. The time-dependent TDM is defined as an implicit density functional, and can be approximately obtained from the time-dependent Kohn-Sham orbitals. The quality of this approximation is assessed in simple model systems. A computational scheme for real molecular systems is presented: the time-dependent Kohn-Sham equations are solved with the OCTOPUS code and the time-dependent Kohn-Sham TDM is calculated using a spatial partitioning scheme. The method is applied to show in real time how locally created electron-hole pairs spread out over neighboring conjugated molecular chains. The coupling mechanism, electron-hole coherence, and the possibility of charge separation are discussed.

Size dependent magnetism of mass selected deposited transition metal clusters

International Nuclear Information System (INIS)

Lau, T.

2002-05-01

The size dependent magnetic properties of small iron clusters deposited on ultrathin Ni/Cu(100) films have been studied with circularly polarised synchrotron radiation. For X-ray magnetic circular dichroism studies, the magnetic moments of size selected clusters were aligned perpendicular to the sample surface. Exchange coupling of the clusters to the ultrathin Ni/Cu(100) film determines the orientation of their magnetic moments. All clusters are coupled ferromagnetically to the underlayer. With the use of sum rules, orbital and spin magnetic moments as well as their ratios have been extracted from X-ray magnetic circular dichroism spectra. The ratio of orbital to spin magnetic moments varies considerably as a function of cluster size, reflecting the dependence of magnetic properties on cluster size and geometry. These variations can be explained in terms of a strongly size dependent orbital moment. Both orbital and spin magnetic moments are significantly enhanced in small clusters as compared to bulk iron, although this effect is more pronounced for the spin moment. Magnetic properties of deposited clusters are governed by the interplay of cluster specific properties on the one hand and cluster-substrate interactions on the other hand. Size dependent variations of magnetic moments are modified upon contact with the substrate. (orig.)

Periodic position dependence of the energy measured in the CMS electromagnetic calorimeter

CERN Document Server

Descamps, Julien

2006-01-01

A uniform energy measurement response of the CMS electromagnetic calorimeter ECAL is essential for precision physics at the LHC. The ECAL barrel calorimeter consists of 61200 lead tungstate crystals arranged in a quasi-projective geometry. The energy of photons reaching the ECAL will be reconstructed by summing the channels corresponding to matrices of 3x3 or 5x5 crystals centred on the crystal with the largest energy deposit. The energy measured using such matrices of fixed size has been studied using electron test beam data taken in 2004. The variation of the energy containment with the incident electron impact position on the central crystal leads to a degradation of the energy resolution. A method using only the calorimeter information is presented to correct for the position dependent response. After correction, the energy resolution performance for uniform impact distributions of the electrons on the front face of a crystal approaches that obtained for maximal containment with a central impact. The univ...

Sensitivity of ion-induced sputtering to the radial distribution of energy transfers: A molecular dynamics study

International Nuclear Information System (INIS)

Mookerjee, S.; Khan, S. A.; Roy, A.; Beuve, M.; Toulemonde, M.

2008-01-01

Using different models for the deposition of energy on the lattice and a classical molecular dynamics approach to the subsequent transport, we evaluate how the details of the energy deposition model influence sputtering yield from a Lennard-Jones target irradiated with a MeV/u ion beam. Two energy deposition models are considered: a uniform, instantaneous deposition into a cylinder of fixed radius around the projectile ion track, used in earlier molecular dynamics and fluid dynamics simulations of sputtering yields; and an energy deposition distributed in time and space based on the formalism developed in the thermal spike model. The dependence of the sputtering yield on the total energy deposited on the target atoms is very sensitive to the energy deposition model. To clarify the origin of this strong dependence, we explore the role of the radial expansion of the electronic system prior to the transfer of its energy to the lattice. The results imply that observables such as the sputtering yield may be used as signatures of the fast electron-lattice energy transfer in the electronic energy-loss regime, and indicate the need for more experimental and theoretical investigations of these processes

Geopressured aquifers - utilization of the energy potential of the Endorf thermal water deposit

Energy Technology Data Exchange (ETDEWEB)

Mueller, S; Hantelmann, G v

1984-01-01

The Endorf thermal water deposit (Rupel, 4229 to 4264 m) belongs to the type of ''geopressured aquifers''. The overall aim of the project is to exploit the energy stored in the deposit in the form of thermal brine (temperature: 115/sup 0/C) and natural gas (96% methane). In this first report on the project state, an overview on prehistory is followed by a description of the currently implemented test programme and its subsequent evaluation which aim at obtaining more exact knowledge concerning the present deposit conditions and, while doing so, indications of the energy content of the deposit in order to determine the energy potential theoretically exploitable at the well head.

Time-dependent dielectric breakdown of atomic-layer-deposited Al2O3 films on GaN

Science.gov (United States)

Hiraiwa, Atsushi; Sasaki, Toshio; Okubo, Satoshi; Horikawa, Kiyotaka; Kawarada, Hiroshi

2018-04-01

Atomic-layer-deposited (ALD) Al2O3 films are the most promising surface passivation and gate insulation layers in non-Si semiconductor devices. Here, we carried out an extensive study on the time-dependent dielectric breakdown characteristics of ALD-Al2O3 films formed on homo-epitaxial GaN substrates using two different oxidants at two different ALD temperatures. The breakdown times were approximated by Weibull distributions with average shape parameters of 8 or larger. These values are reasonably consistent with percolation theory predictions and are sufficiently large to neglect the wear-out lifetime distribution in assessing the long-term reliability of the Al2O3 films. The 63% lifetime of the Al2O3 films increases exponentially with a decreasing field, as observed in thermally grown SiO2 films at low fields. This exponential relationship disproves the correlation between the lifetime and the leakage current. Additionally, the lifetime decreases with measurement temperature with the most remarkable reduction observed in high-temperature (450 °C) O3-grown films. This result agrees with that from a previous study, thereby ruling out high-temperature O3 ALD as a gate insulation process. When compared at 200 °C under an equivalent SiO2 field of 4 MV/cm, which is a design guideline for thermal SiO2 on Si, high-temperature H2O-grown Al2O3 films have the longest lifetimes, uniquely achieving the reliability target of 20 years. However, this target is accomplished by a relatively narrow margin and, therefore, improvements in the lifetime are expected to be made, along with efforts to decrease the density of extrinsic Al2O3 defects, if any, to promote the practical use of ALD Al2O3 films.

Time dependent theory of two-step absorption of two pulses

Energy Technology Data Exchange (ETDEWEB)

Rebane, Inna, E-mail: inna.rebane@ut.ee

2015-09-25

The time dependent theory of two step-absorption of two different light pulses with arbitrary duration in the electronic three-level model is proposed. The probability that the third level is excited at the moment t is found in depending on the time delay between pulses, the spectral widths of the pulses and the energy relaxation constants of the excited electronic levels. The time dependent perturbation theory is applied without using “doorway–window” approach. The time and spectral behavior of the spectrum using in calculations as simple as possible model is analyzed. - Highlights: • Time dependent theory of two-step absorption in the three-level model is proposed. • Two different light pulses with arbitrary duration is observed. • The time dependent perturbation theory is applied without “door–window” approach. • The time and spectral behavior of the spectra is analyzed for several cases.

Collisional energy dependence of molecular ionization by metastable rare gas atoms

International Nuclear Information System (INIS)

Martin, R.M.; Parr, T.P.

1979-01-01

The collisional energy dependence of several molecular total ionization cross sections by metastable rare gas atoms was studied over the thermal energy region using the crossed molecular beam time-of-flight method. Results are reported for the collision systems He, Ne, and Ar ionizing the geometric isomers cis- and trans-dichloroethylene and ortho- and para-dichlorobenzene. The He ionization cross sections oscillate about an energy dependence of E/sup -1/2/ over the energy range 0.004--1.0 eV, and the Ar*+para-dichlorobenzene cross section oscillates about an energy dependence of E/sup -2/5/ over the energy range 0.011--0.64 eV. The remaining systems are characterized by ''bent'' E/sup -m/ dependences with m values of 0.56--0.70 at low energies changing to 0.07--0.29 at higher energies. Comparison with the slopes of the He* systems and the Ar*+para-dichlorobenzene system shows that the ''bent'' and ''oscillating'' energy dependences are similar except for the form of the cross section functions at the lowest energies. No systematic differences are found between the cross section energy dependences for ionization of different geometric isomers or for ionization by the different metastable rare gas atoms

Model of enhanced energy deposition in a Z-pinch plasma

International Nuclear Information System (INIS)

Velikovich, A. L.; Davis, J.; Thornhill, J. W.; Giuliani, J. L. Jr.; Rudakov, L. I.; Deeney, C.

2000-01-01

In numerous experiments, magnetic energy coupled to strongly radiating Z-pinch plasmas exceeds the thermalized kinetic energy, sometimes by a factor of 2-3. An analytical model describing this additional energy deposition based on the concept of macroscopic magnetohydrodynamic (MHD) turbulent pinch heating proposed by Rudakov and Sudan [Phys. Reports 283, 253 (1997)] is presented. The pinch plasma is modeled as a foam-like medium saturated with toroidal ''magnetic bubbles'' produced by the development of surface m=0 Rayleigh-Taylor and MHD instabilities. As the bubbles converge to the pinch axis, their magnetic energy is converted to thermal energy of the plasma through pdV work. Explicit formulas for the average dissipation rate of this process and the corresponding contribution to the resistance of the load, which compare favorably to the experimental data and simulation results, are presented. The possibility of using this enhanced (relative to Ohmic heating) dissipation mechanism to power novel plasma radiation sources and produce high K-shell yields using long current rise time machines is discussed. (c) 2000 American Institute of Physics

Constant resolution of time-dependent Hartree--Fock phase ambiguity

International Nuclear Information System (INIS)

Lichtner, P.C.; Griffin, J.J.; Schultheis, H.; Schultheis, R.; Volkov, A.B.

1978-01-01

The customary time-dependent Hartree--Fock problem is shown to be ambiguous up to an arbitrary function of time additive to H/sub HF/, and, consequently, up to an arbitrary time-dependent phase for the solution, PHI(t). The ''constant'' (H)'' phase is proposed as the best resolution of this ambiguity. It leads to the following attractive features: (a) the time-dependent Hartree--Fock (TDHF) Hamiltonian, H/sub HF/, becomes a quantity whose expectation value is equal to the average energy and, hence, constant in time; (b) eigenstates described exactly by determinants, have time-dependent Hartree--Fock solutions identical with the exact time-dependent solutions; (c) among all possible TDHF solutions this choice minimizes the norm of the quantity (H--i dirac constant delta/delta t) operating on the ket PHI, and guarantees optimal time evolution over an infinitesimal period; (d) this choice corresponds both to the stationary value of the absolute difference between (H) and (i dirac constant delta/delta t) and simultaneously to its absolute minimal value with respect to choice of the time-dependent phase. The source of the ambiguity is discussed. It lies in the time-dependent generalization of the freedom to transform unitarily among the single-particle states of a determinant at the (physically irrelevant for stationary states) cost of altering only a factor of unit magnitude

Investigation of metabolites for estimating blood deposition time.

Science.gov (United States)

Lech, Karolina; Liu, Fan; Davies, Sarah K; Ackermann, Katrin; Ang, Joo Ern; Middleton, Benita; Revell, Victoria L; Raynaud, Florence J; Hoveijn, Igor; Hut, Roelof A; Skene, Debra J; Kayser, Manfred

2018-01-01

Trace deposition timing reflects a novel concept in forensic molecular biology involving the use of rhythmic biomarkers for estimating the time within a 24-h day/night cycle a human biological sample was left at the crime scene, which in principle allows verifying a sample donor's alibi. Previously, we introduced two circadian hormones for trace deposition timing and recently demonstrated that messenger RNA (mRNA) biomarkers significantly improve time prediction accuracy. Here, we investigate the suitability of metabolites measured using a targeted metabolomics approach, for trace deposition timing. Analysis of 171 plasma metabolites collected around the clock at 2-h intervals for 36 h from 12 male participants under controlled laboratory conditions identified 56 metabolites showing statistically significant oscillations, with peak times falling into three day/night time categories: morning/noon, afternoon/evening and night/early morning. Time prediction modelling identified 10 independently contributing metabolite biomarkers, which together achieved prediction accuracies expressed as AUC of 0.81, 0.86 and 0.90 for these three time categories respectively. Combining metabolites with previously established hormone and mRNA biomarkers in time prediction modelling resulted in an improved prediction accuracy reaching AUCs of 0.85, 0.89 and 0.96 respectively. The additional impact of metabolite biomarkers, however, was rather minor as the previously established model with melatonin, cortisol and three mRNA biomarkers achieved AUC values of 0.88, 0.88 and 0.95 for the same three time categories respectively. Nevertheless, the selected metabolites could become practically useful in scenarios where RNA marker information is unavailable such as due to RNA degradation. This is the first metabolomics study investigating circulating metabolites for trace deposition timing, and more work is needed to fully establish their usefulness for this forensic purpose.

Effect of Laser Power and Gas Flow Rate on Properties of Directed Energy Deposition of Titanium Alloy

Science.gov (United States)

Mahamood, Rasheedat M.

2018-03-01

Laser metal deposition (LMD) process belongs to the directed energy deposition class of additive manufacturing processes. It is an important manufacturing technology with lots of potentials especially for the automobile and aerospace industries. The laser metal deposition process is fairly new, and the process is very sensitive to the processing parameters. There is a high level of interactions among these process parameters. The surface finish of part produced using the laser metal deposition process is dependent on the processing parameters. Also, the economy of the LMD process depends largely on steps taken to eliminate or reduce the need for secondary finishing operations. In this study, the influence of laser power and gas flow rate on the microstructure, microhardness and surface finish produced during the laser metal deposition of Ti6Al4V was investigated. The laser power was varied between 1.8 kW and 3.0 kW, while the gas flow rate was varied between 2 l/min and 4 l/min. The microstructure was studied under an optical microscope, the microhardness was studied using a Metkon microhardness indenter, while the surface roughness was studied using a Jenoptik stylus surface analyzer. The results showed that better surface finish was produced at a laser power of 3.0 kW and a gas flow rate of 4 l/min.

The importance of speculative uranium deposits

International Nuclear Information System (INIS)

Kaiser, H.; Roth-Seefrid, H.

1980-01-01

Since current known uranium deposits (5 million t U) will either have been exhausted by the end of the century, or must be held in reserve for the thermal converter reactors which will be in operation by that time, the development of nuclear energy after the year 2000 will depend to a large extent on the early availability of speculative uranium deposits. The speculative deposits represent, by definition, the quantities of uranium which are presumed to exist in addition to the 'known' deposits and which can ultimately be exploited according to current technical-economic and ecological standpoints. When viewed critically, however, the US-DOE model used for this purpose projects an over-optimistic picture of uranium supplies and was, therefore, only accepted by the INFCE with a series of limitations and reservations. Overall the model represents a well-founded reassurance for future uranium exploration - nothing more and nothing less. The model clearly shows that due to the long lead-in times considerable expenditure will be required for uranium exploration in the coming years. It is probable that this level of investment will have to be increased several times over in the 1990s as the search moves to greater depths and to less-accessible regions. (orig./UA) [de

Calorimetric sensors for energy deposition measurements

International Nuclear Information System (INIS)

Langenbrunner, J.; Cooper, R.; Morgan, G.

1998-01-01

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-kΩ 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

Hypersonic wave drag reduction performance of cylinders with repetitive laser energy depositions

International Nuclear Information System (INIS)

Fang, J; Hong, Y J; Li, Q; Huang, H

2011-01-01

It has been widely research that wave drag reduction on hypersonic vehicle by laser energy depositions. Using laser energy to reduce wave drag can improve vehicle performance. A second order accurate scheme based on finite-difference method and domain decomposition of structural grid is used to compute the drag performance of cylinders in a hypersonic flow of Mach number 2 at altitude of 15km with repetitive energy depositions. The effects of frequency on drag reduction are studied. The calculated results show: the recirculation zone is generated due to the interaction between bow shock over the cylinder and blast wave produced by energy deposition, and a virtual spike which is supported by an axis-symmetric recirculation, is formed in front of the cylinder. By increasing the repetitive frequency, the drag is reduced and the oscillation of the drag is decreased; however, the energy efficiency decreases by increasing the frequency.

Energy deposition in a thin copper target downstream and off-axis of a proton-radiography target

International Nuclear Information System (INIS)

Greene, G.A.; Finfrock, C.C.; Snead, C.L.; Hanson, A.L.; Murray, M.M.

2002-01-01

A series of proton energy-deposition experiments was conducted to measure the energy deposited in a copper target located downstream and off-axis of a high-energy proton-radiography target. The proton/target interactions involved low-intensity bunches of protons at 24 GeV/c onto a spherical target consisting of concentric shells of tungsten and copper. The energy-deposition target was placed at five locations downstream of the proton-radiography target, off-axis of the primary beam transport, and was either unshielded or shielded by 5 or 10 cm of lead. Maximum temperature rises measured in the energy-deposition target due to single bunches of 5x10 10 protons on the proton-radiography target were approximately 20 mK per bunch. The data indicated that the scattered radiation was concentrated close to the primary transport axis of the beam line. The energy deposited in the energy-deposition target was reduced by moving the target radially away from the primary transport axis. Placing lead shielding in front of the target further reduced the energy deposition. The measured temperature rises of the energy-deposition target were empirically correlated with the distance from the source, the number of protons incident on the proton-radiography target, the thickness of the lead shielding, and the angle of the energy-deposition target off-axis of the beam line from the proton-radiography target. The correlation of the experimental data that was developed provides a starting point for the evaluation of the shielding requirements for devices downstream of proton-radiography targets such as superconducting magnets

An analytic solution to the time-dependent first-daughter fission-product plateout problem for multi-region isothermal slug flow

International Nuclear Information System (INIS)

Durkee, J.W. Jr.; Lee, C.E.

1985-01-01

The time-dependent, axisymmetric, isothermal slug flow convective-diffusion equation with radioactive decay is solved analytically to predict the behavior of a first-daughter fission-product undergoing gaseous transport through multiple materials in a cylindrical pipe. The integration coefficients are determined using the Davidon variable metric minimization method. The behavior of fission-product material deposited on the conduit wall is described by a standard mass-transfer model. The time-dependent plateout rate behavior, determined previously for parent fission-product deposition, is again evident for daughter product plateout. Dominance of the daughter plateout by parent deposition characteristics is apparent. The determination of the daughter wall mass-transfer and diffusion coefficient using a least-squares analysis of measured data depends upon a reasonably low ratio of parent/daughter half-lives. This is illustrated with 137 Cs/ 137 Ba(=2x10 5 ) and 140 Ba/ 140 La(=7.6), where for 137 Cs/ 137 Ba the solution sensitivity to the 137 Ba deposition parameters is small and for 140 Ba/ 140 La a reasonable solution is readily obtained. (author)

Energy India 'dependence

International Nuclear Information System (INIS)

Cygler, C.

2007-01-01

India has an economic growth between 8 to 10 % by year. To become a great country of the twenty first century and to stop poverty it is necessary to keep this growth but the growth of India is dependant of its ability to supply electric power necessary to increase the industrial production. The country has to multiply by four its energy production. The electric production comes from thermal power plants for 65%, 26% from hydroelectric power plants, 6% from renewable energy sources and 3% from nuclear energy. Between solar energy ( India has three hundred solar days by years) and nuclear energy using thorium that can be increased India has to choose an energy policy to answer its energy demand and independence need. (N.C.)

Plasmonic resonance-enhanced local photothermal energy deposition by aluminum nanoparticles

International Nuclear Information System (INIS)

Chong Xinyuan; Jiang Naibo; Zhang Zhili; Roy, Sukesh; Gord, James R.

2013-01-01

Local energy deposition of aluminum nanoparticles (Al NPs) by localized surface plasmon resonance-enhanced photothermal effects is demonstrated. Low-power light stimuli are efficiently and locally concentrated to trigger the oxidation reactions of Al NPs because of the large ohmic absorption and high reactivity of the Al. Numerical simulations show that both ultraviolet and visible light are more efficient than infrared light for photothermal energy coupling. The natural oxidation layer of alumina is found to have minimum impact on the energy deposition because of its negligible dielectric losses. The near-field distributions of the electric field indicate that slight aggregation induces much higher local enhancement, especially at the interface region of multiple contacting nanoparticles.

Internal energy deposition with silicon nanoparticle-assisted laser desorption/ionization (SPALDI) mass spectrometry

Science.gov (United States)

Dagan, Shai; Hua, Yimin; Boday, Dylan J.; Somogyi, Arpad; Wysocki, Ronald J.; Wysocki, Vicki H.

2009-06-01

The use of silicon nanoparticles for laser desorption/ionization (LDI) is a new appealing matrix-less approach for the selective and sensitive mass spectrometry of small molecules in MALDI instruments. Chemically modified silicon nanoparticles (30 nm) were previously found to require very low laser fluence in order to induce efficient LDI, which raised the question of internal energy deposition processes in that system. Here we report a comparative study of internal energy deposition from silicon nanoparticles to previously explored benzylpyridinium (BP) model compounds during LDI experiments. The internal energy deposition in silicon nanoparticle-assisted laser desorption/ionization (SPALDI) with different fluorinated linear chain modifiers (decyl, hexyl and propyl) was compared to LDI from untreated silicon nanoparticles and from the organic matrix, [alpha]-cyano-4-hydroxycinnamic acid (CHCA). The energy deposition to internal vibrational modes was evaluated by molecular ion survival curves and indicated that the ions produced by SPALDI have an internal energy threshold of 2.8-3.7 eV. This is slightly lower than the internal energy induced using the organic CHCA matrix, with similar molecular survival curves as previously reported for LDI off silicon nanowires. However, the internal energy associated with desorption/ionization from the silicon nanoparticles is significantly lower than that reported for desorption/ionization on silicon (DIOS). The measured survival yields in SPALDI gradually decrease with increasing laser fluence, contrary to reported results for silicon nanowires. The effect of modification of the silicon particle surface with semifluorinated linear chain silanes, including fluorinated decyl (C10), fluorinated hexyl (C6) and fluorinated propyl (C3) was explored too. The internal energy deposited increased with a decrease in the length of the modifier alkyl chain. Unmodified silicon particles exhibited the highest analyte internal energy

Interpretation of monoclinic hafnia valence electron energy-loss spectra by time-dependent density functional theory

Science.gov (United States)

Hung, L.; Guedj, C.; Bernier, N.; Blaise, P.; Olevano, V.; Sottile, F.

2016-04-01

We present the valence electron energy-loss spectrum and the dielectric function of monoclinic hafnia (m -HfO2) obtained from time-dependent density-functional theory (TDDFT) predictions and compared to energy-filtered spectroscopic imaging measurements in a high-resolution transmission-electron microscope. Fermi's golden rule density-functional theory (DFT) calculations can capture the qualitative features of the energy-loss spectrum, but we find that TDDFT, which accounts for local-field effects, provides nearly quantitative agreement with experiment. Using the DFT density of states and TDDFT dielectric functions, we characterize the excitations that result in the m -HfO2 energy-loss spectrum. The sole plasmon occurs between 13 and 16 eV, although the peaks ˜28 and above 40 eV are also due to collective excitations. We furthermore elaborate on the first-principles techniques used, their accuracy, and remaining discrepancies among spectra. More specifically, we assess the influence of Hf semicore electrons (5 p and 4 f ) on the energy-loss spectrum, and find that the inclusion of transitions from the 4 f band damps the energy-loss intensity in the region above 13 eV. We study the impact of many-body effects in a DFT framework using the adiabatic local-density approximation (ALDA) exchange-correlation kernel, as well as from a many-body perspective using "scissors operators" matched to an ab initio G W calculation to account for self-energy corrections. These results demonstrate some cancellation of errors between self-energy and excitonic effects, even for excitations from the Hf 4 f shell. We also simulate the dispersion with increasing momentum transfer for plasmon and collective excitation peaks.

Organic SIMS: the influence of time on the ion yield enhancement by silver and gold deposition

Science.gov (United States)

Adriaensen, L.; Vangaever, F.; Gijbels, R.

2004-06-01

A series of organic dyes and pharmaceuticals was used to study the secondary ion yield enhancement by metal deposition. The molecules were dissolved in methanol and spincasted on silicon substrates. Subsequently, silver or gold was evaporated on the samples to produce a very thin coating. The coated samples, when measured with TOF-SIMS, showed a considerable increase in characteristic secondary ion intensity. Gold-evaporated samples appear to exhibit the highest signal enhancement. These observations apply to organic samples in general, an advantage that allows to use the technique of metal deposition on real-world samples. However, the observed signal increase does not occur at any given moment. The time between metal deposition on the sample surface and the measuring of the sample with TOF-SIMS appears to have an important influence on the enhancement of the secondary ion intensities. In consideration of these observations several experiments were carried out, in which the spincasted samples were measured at different times after sample preparation, i.e., after gold or silver was deposited on the sample surface. The results show that, depending on the sample and the metal deposited, the secondary ion signals reach their maximum at different times. Further study will be necessary to detect the mechanism responsible for the observed enhancement effect.

An efficient and accurate method to obtain the energy-dependent Green function for general potentials

International Nuclear Information System (INIS)

Kramer, T; Heller, E J; Parrott, R E

2008-01-01

Time-dependent quantum mechanics provides an intuitive picture of particle propagation in external fields. Semiclassical methods link the classical trajectories of particles with their quantum mechanical propagation. Many analytical results and a variety of numerical methods have been developed to solve the time-dependent Schroedinger equation. The time-dependent methods work for nearly arbitrarily shaped potentials, including sources and sinks via complex-valued potentials. Many quantities are measured at fixed energy, which is seemingly not well suited for a time-dependent formulation. Very few methods exist to obtain the energy-dependent Green function for complicated potentials without resorting to ensemble averages or using certain lead-in arrangements. Here, we demonstrate in detail a time-dependent approach, which can accurately and effectively construct the energy-dependent Green function for very general potentials. The applications of the method are numerous, including chemical, mesoscopic, and atomic physics

Exactly solvable quantum state reduction models with time-dependent coupling

International Nuclear Information System (INIS)

Brody, Dorje C; Constantinou, Irene C; Dear, James D C; Hughston, Lane P

2006-01-01

A closed-form solution to the energy-based stochastic Schroedinger equation with a time-dependent coupling is obtained. The solution is algebraic in character, and is expressed directly in terms of independent random data. The data consist of (i) a random variable H which has the distribution P(H=E i ) = π i , where π i is the transition probability vertical bar (ψ 0 vertical bar Φ i ) vertical bar 2 from the initial state vertical bar ψ 0 ) to the Lueders state vertical bar Φ i ) with energy E i , and (ii) an independent P-Brownian motion, where P is the physical probability measure associated with the dynamics of the reduction process. When the coupling is time independent, it is known that state reduction occurs asymptotically-that is to say, over an infinite time horizon. In the case of a time-dependent coupling, we show that if the magnitude of the coupling decreases sufficiently rapidly, then the energy variance will be reduced under the dynamics, but the state need not reach an energy eigenstate. This situation corresponds to the case of a 'partial' or 'incomplete' measurement of the energy. We also construct an example of a model where the opposite situation prevails, in which complete state reduction is achieved after the passage of a finite period of time

On the role of energy deposition in triggering SEGR in power MOSFETs

International Nuclear Information System (INIS)

Selva, L.E.; Swift, G.M.; Taylor, W.A.; Edmonds, L.D.

1999-01-01

Single event gate rupture (SEGR) was studied using three types of power MOSFET devices with ions having incident linear energy transfers (LETs) in silicon from 26 to 82 MeV·cm 2 /mg. Results are: (1) consistent with Wrobel's oxide breakdown for V DS = 0 volts (for both normal incidence and angle); and (2) when V GS = 0 volts, energy deposited near the Si/SiO 2 interface is more important than the energy deposited deeper in the epi

Effect of electron degeneracy on fast-particles energy deposition in dense plasma systems

International Nuclear Information System (INIS)

Johzaki, T.; Nakao, Y.; Nakashima, H.; Kudo, K.

1997-01-01

The effects of electron degeneracy on fast-particles energy deposition in dense plasmas are investigated by making transport calculations for the fast particles. It is found that the degeneracy substantially affects the profiles of energy deposition of 3.52-MeV α-particles. On the other hand, the effect on the energy deposition of 14.1-MeV neutrons is negligibly small because the recoil ions, which transfer the neutron energy to the plasma constituents, are produced in a whole plasma volume due to the long mean-free-path of neutrons. The coupled transport-hydrodynamic calculations show that these effects of degeneracy are negligible in the ignition and burn characteristics of central ignition D-T targets. (author)

The deposition of aerosols on cylinders in crossflow: a time dependent study

International Nuclear Information System (INIS)

Ilias, S.; Douglas, P.L.

1985-01-01

This paper discusses the study of the deposition of aerosols on cylinders due to inertial impaction based on the solution of Navier-Stokes equation. The solution of the velocity-stream function formulation of Navier-Stokes equation can simulate a realistic flow field for virtually an unlimited range of Reynolds number

Residual energy deposition in dental enamel during IR laser ablation at 2.79, 2.94, 9.6, and 10.6 μm

Science.gov (United States)

Ragadio, Jerome N.; Lee, Christian K.; Fried, Daniel

2000-03-01

The objective of this study was to measure the residual heat deposition during laser ablation at those IR laser wavelengths best suited for the removal of dental caries. The principal factor limiting the rate of laser ablation of dental hard tissue is the risk of excessive heat accumulation in the tooth, which has the potential for causing damage to the pulp. Optimal laser ablation systems minimize the residual energy deposition in the tooth by transferring deposited laser energy to kinetic and internal energy of ejected tissue components. The residual heat deposition in the tooth was measured at laser wavelengths of 2.79, 2.94, 9.6 and 10.6 micrometer and pulse widths of 150 ns - 150 microsecond(s) . The residual energy was at a minimum for fluences well above the ablation threshold where it saturates at values from 25 - 70% depending on pulse duration and wavelength for the systems investigated. The lowest values of the residual energy were measured for short (less than 20 microseconds) CO2 laser pulses at 9.6 micrometer and for Q-switched erbium laser pulses. This work was supported by NIH/NIDCR R29DE12091 and the Center for Laser Applications in Medicine, DOE DEFG0398ER62576.

Vacuum radiation induced by time dependent electric field

Directory of Open Access Journals (Sweden)

Bo Zhang

2017-04-01

Full Text Available Many predictions of new phenomena given by strong field quantum electrodynamics (SFQED will be tested on next generation multi-petawatt laser facilities in the near future. These new phenomena are basis to understand physics in extremely strong electromagnetic fields therefore have attracted wide research interest. Here we discuss a new SFQED phenomenon that is named as vacuum radiation. In vacuum radiation, a virtual electron loop obtain energy from time dependent external electric field and radiate an entangled photon pair. Features of vacuum radiation in a locally time dependent electric field including spectrum, characteristic temperature, production rate and power are given.

Vacuum radiation induced by time dependent electric field

Energy Technology Data Exchange (ETDEWEB)

Zhang, Bo, E-mail: zhangbolfrc@caep.cn [Department of High Energy Density Physics, Research Center of Laser Fusion, 621900, Mianyang, Sichuan (China); Laboratory of Science and Technology on Plasma Physics, Research Center of Laser Fusion, 621900, Mianyang, Sichuan (China); Zhang, Zhi-meng; Hong, Wei; He, Shu-Kai; Teng, Jian [Department of High Energy Density Physics, Research Center of Laser Fusion, 621900, Mianyang, Sichuan (China); Laboratory of Science and Technology on Plasma Physics, Research Center of Laser Fusion, 621900, Mianyang, Sichuan (China); Gu, Yu-qiu, E-mail: yqgu@caep.cn [Department of High Energy Density Physics, Research Center of Laser Fusion, 621900, Mianyang, Sichuan (China); Laboratory of Science and Technology on Plasma Physics, Research Center of Laser Fusion, 621900, Mianyang, Sichuan (China)

2017-04-10

Many predictions of new phenomena given by strong field quantum electrodynamics (SFQED) will be tested on next generation multi-petawatt laser facilities in the near future. These new phenomena are basis to understand physics in extremely strong electromagnetic fields therefore have attracted wide research interest. Here we discuss a new SFQED phenomenon that is named as vacuum radiation. In vacuum radiation, a virtual electron loop obtain energy from time dependent external electric field and radiate an entangled photon pair. Features of vacuum radiation in a locally time dependent electric field including spectrum, characteristic temperature, production rate and power are given.

Energy deposition around swift proton tracks in polymethylmethacrylate: How much and how far

Science.gov (United States)

Dapor, Maurizio; Abril, Isabel; de Vera, Pablo; Garcia-Molina, Rafael

2017-08-01

The use of proton beams in several modern technologies to probe or modify the properties of materials, such as proton beam lithography or ion beam cancer therapy, requires us to accurately know the extent to which the energy lost by the swift projectiles in the medium is redistributed radially around their tracks, since this determines several endpoints, such as the resolution of imaging or manufacturing techniques, or even the biological outcomes of radiotherapy. In this paper, the radial distribution of the energy deposited around swift-proton tracks in polymethylmethacrylate (PMMA) by the transport of secondary electrons is obtained by means of a detailed Monte Carlo simulation. The initial energy and angular distributions of the secondary electrons generated by proton impact, as well as the electronic cross sections for the ejection of these electrons, are reliably calculated in the framework of the dielectric formalism, where a realistic electronic excitation spectrum of PMMA is accounted for. The cascade of all secondary electrons generated in PMMA is simulated taking into account the main interactions that occur between these electrons and the condensed phase target. After analyzing the influence that several angular distributions of the electrons generated by the proton beam have on the resulting radial profiles of deposited energy, we conclude that the widely used Rudd and Kim formula should be replaced by the simpler isotropic angular distribution, which leads to radial energy distributions comparable to the ones obtained from more realistic angular distributions. By studying the dependence of the radial dose on the proton energy we recommend lower proton energies than previously published for reducing proximity effects around a proton track. The obtained results are of relevance for assessing the resolution limits of proton beam based imaging and manufacturing techniques.

Numerical study on increasing mass flow ratio by energy deposition of high frequency pulsed laser

International Nuclear Information System (INIS)

Wang Diankai; Hong Yanji; Li Qian

2013-01-01

The mass flow ratio (MFR) of air breathing ramjet inlet would be decreased, when the Mach number is lower than the designed value. High frequency pulsed laser energy was deposited upstream of the cowl lip to reflect the stream so as to increase the MFR. When the Mach number of the flow was 5.0, and the static pressure and temperature of the flow were 2 551.6 Pa and 116.7 K, respectively, two-dimensional non-stationary compressible RANS equations were solved with upwind format to study the mechanisms of increasing MFR by high frequency pulsed laser energy deposition. The laser deposition frequency was 100 kHz and the average power was 500 W. The crossing point of the first forebody oblique shock and extension line of cowl lip was selected as the expected point. Then the deposition position was optimized by searching near the expected point. The results indicate that with the optimization of laser energy deposition position, the MFR would be increased from 63% to 97%. The potential value of increasing MFR by high frequency pulsed laser energy deposition was proved. The method for selection of the energy deposition position was also presented. (authors)

Cumulative Beam Breakup with Time-Dependent Parameters

CERN Document Server

Delayen, J R

2004-01-01

A general analytical formalism developed recently for cumulative beam breakup (BBU) in linear accelerators with arbitrary beam current profile and misalignments [1] is extended to include time-dependent parameters such as energy chirp or rf focusing in order to reduce BBU-induced instabilities and emittance growth. Analytical results are presented and applied to practical accelerator configurations.

Distributional curvature of time-dependent cosmic strings

OpenAIRE

Wilson, J P

1997-01-01

Colombeau's theory of generalised functions is used to calculate the contributions, at the rotation axis, to the distributional curvature for a time-dependent radiating cosmic string, and hence the mass per unit length of the string source. This mass per unit length is compared with the mass at null infinity, giving evidence for a global energy conservation law.

Electron transfer in organic glass. Distance and energy dependence

International Nuclear Information System (INIS)

Krongauz, V.V.

1992-01-01

The authors have investigated the distance and energy dependence of electron transfer in rigid organic glasses containing randomly dispersed electron donor and electron acceptor molecules. Pulsed radiolysis by an electron beam from a linear accelerator was used for ionization resulting in charge deposition on donor molecules. The disappearance kinetics of donor radical anions due to electron transfer to acceptor was monitored spectroscopically by the change in optical density at the wavelength corresponding to that of donor radical anion absorbance. It was found that the rate of the electron transfer observed experimentally was higher than that computed using the Marcus-Levich theory assuming that the electron-transfer activation barrier is equal to the binding energy of electron on the donor molecule. This discrepancy between the experimental and computed results suggests that the open-quotes inertclose quotes media in which electron-transfer reaction takes place may be participating in the process, resulting in experimentally observed higher electron-transfer rates. 32 refs., 3 figs., 2 tabs

Beryllium-7 and {sup 210}Pb atmospheric deposition measured in moss and dependence on cumulative precipitation

Energy Technology Data Exchange (ETDEWEB)

Krmar, M., E-mail: krmar@df.uns.ac.rs [Faculty of Science, Physics Department, Trg Dositeja Obradovića 4, Novi Sad (Serbia); Mihailović, D.T.; Arsenić, I. [Faculty of Agriculture, Trg Dositeja Obradovića 8, Novi Sad (Serbia); Radnović, D. [Faculty of Science, Biology Department, Trg Dositeja Obradovića 4, Novi Sad (Serbia); Pap, I. [Faculty of Agriculture, Trg Dositeja Obradovića 8, Novi Sad (Serbia)

2016-01-15

This paper focuses on analysis of the time series of {sup 7}Be and {sup 210}Pb activity measured in moss, and the amount, as well as duration of precipitation, to gain a better understanding of the possible relationships between airborne radionuclide deposition and precipitation. Here we consider whether the amount of these airborne radionuclides in moss samples is a cumulative measure of radionuclide deposition and decay, and a new approach for analyses of the relationships between precipitation and moss activity concentrations is suggested. Through these analyses it was shown that comparison of cumulative activity measured at one location using moss, normalized by values of cumulative amount or duration of precipitation, showed different regimes of airborne radionuclide deposition. - Graphical abstract: Correlation between cumulative activity of {sup 7}Be and {sup 210}Pb measured in moss samples normalized by the cumulative precipitation. - Highlights: • Use of mosses in measurement of airborne radionuclides deposition was investigated • Prior work indicated {sup 7}Be and {sup 210}Pb activities were not correlated with precipitation • This is unusual since radionuclides moss tissues depends on depositional fluxes. • A new method for study of {sup 7}Be and {sup 210}Pb depositional dynamics was developed • Different seasonal regimes of {sup 7}Be deposition are more noticeable in new technique.

US oil dependency and energy security

International Nuclear Information System (INIS)

Noel, P.

2002-01-01

The three papers of this document were written in the framework of a seminar organized the 30 may 2002 by the IFRI in the framework of its program Energy and Climatic Change. The first presentation deals with the american oil policy since 1980 (relation between the oil dependence and the energy security, the Reagan oil policy, the new oil policy facing the increase of the dependence). The second one deals with the US energy security (oil security, domestic energy security, policy implications). The last presentation is devoted to the US oil dependence in a global context and the problems and policies of international energy security. (A.L.B.)

High-energy high-rate pulsed-power processing of materials by powder consolidation and by railgun deposition. Technical report (Final), 10 April 1985-10 February 1987

Energy Technology Data Exchange (ETDEWEB)

Persad, C.; Marcus, H.L.; Weldon, W.F.

1987-03-31

This exploratory research program was initiated to investigate the potential of using pulse power sources for powder consolidation, deposition and other high-energy high-rate processing. The characteristics of the high-energy-high-rate (1MJ/s) powder consolidation using megampere current pulses from a homopolar generator, were defined. Molybdenum Alloy TZM, a nickel-based metallic glass, copper/graphite composites, and P/M aluminum alloy X7091 were investigated. The powder-consolidation process produced high densification rates. Density values of 80% to 99% could be obtained with subsecond high-temperature exposure. Specific energy input and applied pressure were controlling process parameters. Time temperature transformation (TTT) concepts underpin a fundamental understanding of pulsed power processing. Inherent control of energy input, and time-to-peak processing temperature developed to be held to short times. Deposition experiments were conducted using an exploding-foil device (EFD) providing an armature feed to railgun mounted in a vacuum chamber. The material to be deposited - in plasma, gas, liquid, or solid state - was accelerated electromagnetically in the railgun and deposited on a substrate. Deposits of a wide variety of single- and multi-specie materials were produced on several types of substrates. In a series of ancillary experiments, pulsed-skin-effect heating and self quenching of metallic conductors was discovered to be a new means of surface modification by high-energy high-rate-processing.

Time-dependent crack growth and fracture in concrete

International Nuclear Information System (INIS)

Zhou Fan Ping.

1992-02-01

The objectives of this thesis are to study time-dependent fracture behaviour in concrete. The thesis consists of an experimental study, costitutive modelling and numerical analysis. The experimental study was undertaken to investigate the influences of time on material properties for the fracture process zone and on crack growth and fracture in plain concrete structures. The experiments include tensile relaxation tests, bending tests on notched beams to determine fracture energy at varying deflection rates, and sustained bending and compact tensile tests. From the tensile relaxation tests, the envelope of the σ-w relation does not seem to be influenced by holding periods, though some local detrimental effect does occur. Fracture energy seems to decrease as rates become slower. In the sustained loading tests, deformation (deflection or CMOD) growth curves display three stages, as usually observed in a creep rupture test. The secondary stage dominates the whole failure lifetime, and the secondary deformation rate appears to have good correlation with the failure lifetime. A crack model for time-dependent fracture is proposed, by applying the idea of the Fictitious Crack Model. In this model, a modified Maxwell model is introduced for the fracture process zone incorporated with the static σ-w curve as a failure criterion, based on the observation of the tensile relaxation tests. The time-dependent σ-w curve is expressed in an incremental law. The proposed model has been implemented in a finite element program and applied to simulating sustained flexural and compact tensile tests. Numerical analysis includes simulations of crack growth, load-CMOD curves, stress-failure lifetime curves, size effects on failure life etc. The numerical results indicate that the model seems to be able to properly predict the main features of time-dependent fracture behaviour in concrete, as compared with the experimental results. 97 refs

Time-dependent nonlinear cosmic ray shocks confirming abstract

International Nuclear Information System (INIS)

Dorfi, E.A.

1985-01-01

Numerical studies of time dependent cosmic ray shock structures in planar geometry are interesting because analytical time-independent solutions are available which include the non-linear reactions on the plasma flow. A feature of these time asymptotic solutions is that for higher Mach numbers (M approximately 5) and for a low cosmic ray upstream pressure the solution is not uniquely determined by the usual conservation laws of mass, momentum and energy. These numerical solutions clearly indicate that much work needs to be done before we understand shock acceleration as a time dependent process. The slowness of the process is possibly due to the fact that there is a diffusive flux into the downstream region in addition to the usual advective losses. Analytic investigations of this phenomenon are required

A three-dimensional methodology for the assessment of neutron damage and nuclear energy deposition in graphite components of advanced gas-cooled reactors

Energy Technology Data Exchange (ETDEWEB)

Morgan, D.O.; Robinson, A.T.; Allen, D.A.; Picton, D.J.; Thornton, D.A. [TCS, Serco, Rutherford House, Olympus Park, Quedgeley, Gloucester, Gloucestershire GL2 4NF (United Kingdom); Shaw, S.E. [EDF Energy, Barnet Way, Barnwood, Gloucester GL4 3RS (United Kingdom)

2011-07-01

This paper describes the development of a three-dimensional methodology for the assessment of neutron damage and nuclear energy deposition (or nuclear heating) throughout the graphite cores of the UK's Advanced Gas-cooled Reactors. Advances in the development of the Monte Carlo radiation transport code MCBEND have enabled the efficient production of detailed fully three-dimensional models that utilise three-dimensional source distributions obtained from Core Follow data supplied by the reactor physics code PANTHER. The calculational approach can be simplified to reduce both the requisite number of intensive radiation transport calculations, as well as the quantity of data output. These simplifications have been qualified by comparison with explicit calculations and they have been shown not to introduce significant systematic uncertainties. Simple calculational approaches are described that allow users of the data to address the effects on neutron damage and nuclear energy deposition predictions of the feedback resulting from the mutual dependencies of graphite weight loss and nuclear energy deposition. (authors)

Collision dynamics of H+ + N2 at low energies based on time-dependent density-functional theory

Science.gov (United States)

Yu, W.; Zhang, Y.; Zhang, F. S.; Hutton, R.; Zou, Y.; Gao, C.-Z.; Wei, B.

2018-02-01

Using time-dependent density-functional theory at the level of local density approximation augmented by a self-interaction correction and coupled non-adiabatically to molecular dynamics, we study, from a theoretical perspective, scattering dynamics of the proton in collisions with the N2 molecule at 30 eV. Nine different collision configurations are employed to analyze the proton energy loss spectra, electron depletion, scattering angles and self-interaction effects. Our results agree qualitatively with the experimental data and previous theoretical calculations. The discrepancies are ascribed to the limitation of the theoretical models in use. We find that self-interaction effects can significantly influence the electron capture and the excited diatomic vibrational motion, which is in consistent with other calculations. In addition, it is found that the molecular structure can be readily retrieved from the proton energy loss spectra due to a significant momentum transfer in head-on collisions.

Revisiting gamma-ray burst afterglows with time-dependent parameters

Science.gov (United States)

Yang, Chao; Zou, Yuan-Chuan; Chen, Wei; Liao, Bin; Lei, Wei-Hua; Liu, Yu

2018-02-01

The relativistic external shock model of gamma-ray burst (GRB) afterglows has been established with five free parameters, i.e., the total kinetic energy E, the equipartition parameters for electrons {{ε }}{{e}} and for the magnetic field {{ε }}{{B}}, the number density of the environment n and the index of the power-law distribution of shocked electrons p. A lot of modified models have been constructed to consider the variety of GRB afterglows, such as: the wind medium environment by letting n change with radius, the energy injection model by letting kinetic energy change with time and so on. In this paper, by assuming all four parameters (except p) change with time, we obtain a set of formulas for the dynamics and radiation, which can be used as a reference for modeling GRB afterglows. Some interesting results are obtained. For example, in some spectral segments, the radiated flux density does not depend on the number density or the profile of the environment. As an application, through modeling the afterglow of GRB 060607A, we find that it can be interpreted in the framework of the time dependent parameter model within a reasonable range.

Energy deposition patterns within limb models heated with a mini annular phased array (MAPA) applicator

International Nuclear Information System (INIS)

Guerquin-Kern, J.L.; Hagmann, M.J.; Charny, C.K.; Levin, R.L.

1986-01-01

A series of experiments has been carried out in order to characterize a MAPA applicator prior to possible clinical implementation. The energy deposition patterns were determined in several human limb models of different complexities. The maximum energy deposition observed in a homogeneous cylindrical phantom was found to be at the middle of the applicator. For more realistically shaped, homogeneous limb models, the point of maximum energy deposition was shifted towards a smaller cross-sectional region; this was also the case for isolated human legs. Furthermore, significant heating was observed in the bone of the isolated legs. Such phenomena illustrate the limitation of using classical 2-D numerical models for predicting the energy deposition patterns in heterogeneous bodies

Laser-Aided Directed Energy Deposition of Steel Powder over Flat Surfaces and Edges.

Science.gov (United States)

Caiazzo, Fabrizia; Alfieri, Vittorio

2018-03-16

In the framework of Additive Manufacturing of metals, Directed Energy Deposition of steel powder over flat surfaces and edges has been investigated in this paper. The aims are the repair and overhaul of actual, worn-out, high price sensitive metal components. A full-factorial experimental plan has been arranged, the results have been discussed in terms of geometry, microhardness and thermal affection as functions of the main governing parameters, laser power, scanning speed and mass flow rate; dilution and catching efficiency have been evaluated as well to compare quality and effectiveness of the process under conditions of both flat and edge depositions. Convincing results are presented to give grounds for shifting the process to actual applications: namely, no cracks or pores have been found in random cross-sections of the samples in the processing window. Interestingly an effect of the scanning conditions has been proven on the resulting hardness in the fusion zone; therefore, the mechanical characteristics are expected to depend on the processing parameters.

Effects of various deposition times and RF powers on CdTe thin film growth using magnetron sputtering

Science.gov (United States)

Ghorannevis, Z.; Akbarnejad, E.; Ghoranneviss, M.

2016-09-01

Cadmium telluride (CdTe) is a p-type II-VI compound semiconductor, which is an active component for producing photovoltaic solar cells in the form of thin films, due to its desirable physical properties. In this study, CdTe film was deposited using the radio frequency (RF) magnetron sputtering system onto a glass substrate. To improve the properties of the CdTe film, effects of two experimental parameters of deposition time and RF power were investigated on the physical properties of the CdTe films. X-ray Diffraction (XRD), atomic force microscopy (AFM) and spectrophotometer were used to study the structural, morphological and optical properties of the CdTe samples grown at different experimental conditions, respectively. Our results suggest that film properties strongly depend on the experimental parameters and by optimizing these parameters, it is possible to tune the desired structural, morphological and optical properties. From XRD data, it is found that increasing the deposition time and RF power leads to increasing the crystallinity as well as the crystal sizes of the grown film, and all the films represent zinc blende cubic structure. Roughness values given from AFM images suggest increasing the roughness of the CdTe films by increasing the RF power and deposition times. Finally, optical investigations reveal increasing the film band gaps by increasing the RF power and the deposition time.

AN ENERGY-CONSERVING, PARTICLE-DOMINATED, TIME-DEPENDENT MODEL OF 3C 58 AND ITS OBSERVABILITY AT HIGH ENERGIES

Energy Technology Data Exchange (ETDEWEB)

Torres, Diego F.; Martin Rodriguez, Jonatan [Institute of Space Sciences (IEEC-CSIC), Campus UAB, Torre C5, 2a planta, E-08193 Barcelona (Spain); Cillis, Analia N. [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67-Suc. 28 (C1428ZAA), Buenos Aires (Argentina)

2013-01-20

We present a time-dependent spectral model of the nebula 3C 58 and compare it with available data. The model is for a leptonic nebula in which particles are subject to synchrotron, inverse Compton, self-synchrotron Compton, adiabatic, and bremsstrahlung processes. We find that 3C 58 is compatible with being a particle-dominated nebula, with a magnetic field of 35 {mu}G. A broken power-law injection fits well the multi-frequency data, with a break energy at about 40 GeV. We find that 3C 58 is not expected to appear in VERITAS or MAGIC II, unless the local IR background is a factor of {approx}20 off Galactic models' averages. For cases in which the cosmic microwave background dominates the inverse Compton contribution, we find that 3C 58 will not be visible either for the Cherenkov Telescope Array.

Remarks on saturation of energy confinement in high density regime on LHD

International Nuclear Information System (INIS)

Yamada, Hiroshi; Morita, Shigeru; Murakami, Sadayoshi

2003-01-01

A study on energy confinement times in currentless helical plasmas has indicated a preferable density dependence like τ E ∝ n-bar e 0.5-0.6 . However, saturation of energy confinement time has been often observed during the density ramping-up phase by gas puffing in NBI heated plasmas in LHD. The power balance analysis indicates that the thermal diffusivity is improved by the increase in local density while the global energy confinement time loses the dependence on the density. The flat or hollow density profile, which is distinguished in the density-ramping phase, promotes a broad heat power deposition. This change explains the apparent contradiction between the density dependence of the thermal diffusivity and the global energy confinement time. This result suggests that central heating can maintain a favorable density dependence of the energy confinement time in the high density regime. (author)

Studies on the high electronic energy deposition in polyaniline thin films

International Nuclear Information System (INIS)

Deshpande, N.G.; Gudage, Y.G.; Vyas, J.C.; Singh, F.; Sharma, Ramphal

2008-01-01

We report here the physico-chemical changes brought about by high electronic energy deposition of gold ions in HCl doped polyaniline (PANI) thin films. PANI thin films were synthesized by in situ polymerization technique. The as-synthesized PANI thin films of thickness 160 nm were irradiated using Au 7+ ion of 100 MeV energy at different fluences, namely, 5 x 10 11 ions/cm 2 and 5 x 10 12 ions/cm 2 , respectively. A significant change was seen after irradiation in electrical and photo conductivity, which may be related to increased carrier concentration, and structural modifications in the polymer film. In addition, the high electronic energy deposition showed other effects like cross-linking of polymer chains, bond breaking and creation of defect sites. AFM observations revealed mountainous type features in all (before and after irradiation) PANI samples. The average size (diameter) and density of such mountainous clusters were found to be related with the ion fluence. The AFM profiles also showed change in the surface roughness of the films with respect to irradiation, which is one of the peculiarity of the high electronic energy deposition technique

A time-dependent dusty gas dynamic model of axisymmetric cometary jets

International Nuclear Information System (INIS)

Korosmezey, A.; Gombosi, T.I.

1990-01-01

The present time-dependent, axisymmetric dusty gas dynamical model of inner cometary atmospheres solves the coupled and time-dependent equations of continuity, momentum, and energy for a gas-dust mixture between the surface of the nucleus and 100 km, using an axisymmetric 40 x 40 grid structure. A novel numerical method employing a second-order accurate Godunov-type scheme with dimensional splitting is used to solve the time-dependent pde system. It is established that a subsolar dust spike not predicted by previous calculations is generated by narrow axisymmetric jets, together with a jet cone whose opening angle depends on the jet length. 28 refs

Electron energy deposition in the middle atmosphere

International Nuclear Information System (INIS)

Vampola, A.L.; Gorney, D.J.

1983-01-01

Spectra of locally precipating 36- to 317-keV electrons obtained by instrumentation on the S3-2 satellite are used to calculate energy deposition profiles as a function of latitude, longitude, and altitude. In the 70- to 90-km altitude, mid-latitude ionization due to these precipitating energetic electrons can be comparable to that due to direct solar H Lyman α. At night, the electrons produce ionization more than an order of magnitude greater than that expected from scattered H Lyman α. Maximum precipitation rates in the region of the South Atlantic Anomaly are of the order of 10 -2 erg/cm 2 s with a spectrum of form j(E) = 1.34 x 10 5 E/sup -2.27/ (keV). Southern hemisphere precipitation dominates that in the north for 1.1< L<6 except for regions of low local surface field in the northern hemisphere. Above L = 6, local time effects dominate: i.e., longitudinal effects due to the asymmetric magnetic field which are strong features below L = 6 disappear and are replaced by high-latitude precipitation events which are local time features

Action dependent heuristic dynamic programming based residential energy scheduling with home energy inter-exchange

International Nuclear Information System (INIS)

Xu, Yancai; Liu, Derong; Wei, Qinglai

2015-01-01

Highlights: • The algorithm is developed in the two-household energy management environment. • We develop the absent energy penalty cost for the first time. • The algorithm has ability to keep adapting in real-time operations. • Its application can lower total costs and achieve better load balancing. - Abstract: Residential energy scheduling is a hot topic nowadays in the background of energy saving and environmental protection worldwide. To achieve this objective, a new residential energy scheduling algorithm is developed for energy management, based on action dependent heuristic dynamic programming. The algorithm works under the circumstance of residential real-time pricing and two adjacent housing units with energy inter-exchange, which can reduce the overall cost and enhance renewable energy efficiency after long-term operation. It is designed to obtain the optimal control policy to manage the directions and amounts of electricity energy flux. The algorithm’s architecture is mainly constructed based on neural networks, denoting the learned characteristics in the linkage of layers. To get close to real situations, many constraints such as maximum charging/discharging power of batteries are taken into account. The absent energy penalty cost is developed for the first time as a part of the performance index function. When the environment changes, the residential energy scheduling algorithm gains new features and keeps adapting in real-time operations. Simulation results show that the developed algorithm is beneficial to energy conversation

Wave function for time-dependent harmonically confined electrons in a time-dependent electric field.

Science.gov (United States)

Li, Yu-Qi; Pan, Xiao-Yin; Sahni, Viraht

2013-09-21

The many-body wave function of a system of interacting particles confined by a time-dependent harmonic potential and perturbed by a time-dependent spatially homogeneous electric field is derived via the Feynman path-integral method. The wave function is comprised of a phase factor times the solution to the unperturbed time-dependent Schrödinger equation with the latter being translated by a time-dependent value that satisfies the classical driven equation of motion. The wave function reduces to that of the Harmonic Potential Theorem wave function for the case of the time-independent harmonic confining potential.

37 CFR 1.804 - Time of making an original deposit.

Science.gov (United States)

2010-07-01

... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Time of making an original... of Biological Material § 1.804 Time of making an original deposit. (a) Whenever a biological material is specifically identified in an application for patent as filed, an original deposit thereof may be...

Control of ordered mesoporous titanium dioxide nanostructures formed using plasma enhanced glancing angle deposition

Energy Technology Data Exchange (ETDEWEB)

Gibson, Des [Institute of Thin Films, Sensors & Imaging, Scottish Universities Physics Alliance, University of West of Scotland, Paisley, PA1 2BE (United Kingdom); Child, David, E-mail: david.child@uws.ac.uk [Institute of Thin Films, Sensors & Imaging, Scottish Universities Physics Alliance, University of West of Scotland, Paisley, PA1 2BE (United Kingdom); Song, Shigeng; Zhao, Chao [Institute of Thin Films, Sensors & Imaging, Scottish Universities Physics Alliance, University of West of Scotland, Paisley, PA1 2BE (United Kingdom); Alajiani, Yahya [Institute of Thin Films, Sensors & Imaging, Scottish Universities Physics Alliance, University of West of Scotland, Paisley, PA1 2BE (United Kingdom); Department of Physics, Faculty of Science, Jazan University, Jazan (Saudi Arabia); Waddell, Ewan [Thin Film Solutions Ltd, West of Scotland Science Park, Glasgow, G20 0TH (United Kingdom)

2015-10-01

Three dimensional nanostructures of mesoporous (pore diameter between 2-50 nm) nanocrystalline titania (TiO{sub 2}) were produced using glancing angle deposition combined with plasma ion assisted deposition, providing plasma enhanced glancing angle deposition eliminating the need for post-annealing to achieve film crystallinity. Electron beam evaporation was chosen to deposit nanostructures at various azimuthal angles, achieving designed variation in three dimensional nanostructure. A thermionic broad beam hollow cathode plasma source was used to enhance electron beam deposition, with ability to vary in real time ion fluxes and energies providing a means to modify and control TiO{sub 2} nanostructure real time with controlled density and porosity along and lateral to film growth direction. Plasma ion assisted deposition was carried out at room temperature using a hollow cathode plasma source, ensuring low heat loading to the substrate during deposition. Plasma enhanced glancing angle TiO{sub 2} structures were deposited onto borosilicate microscope slides and used to characterise the effects of glancing angle and plasma ion energy distribution function on the optical and nanostructural properties. Variation in TiO{sub 2} refractive index from 1.40 to 2.45 (@ 550 nm) using PEGLAD is demonstrated. Results and analysis of the influence of plasma enhanced glancing angle deposition on evaporant path and resultant glancing angle deviation from standard GLAD are described. Control of mesoporous morphology is described, providing a means of optimising light trapping features and film porosity, relevant to applications such as fabrication of dye sensitised solar cells. - Highlights: • Plasma assistance during glancing angle deposition enables control of morphology. • Ion energy variation during glancing angle deposition varies columnar angle • Column thickness of glancing angle deposition dependant on ion current density • Ion current density variation during

Cumulative percent energy deposition of photon beam incident on different targets, simulated by Monte Carlo

International Nuclear Information System (INIS)

Kandic, A.; Jevremovic, T.; Boreli, F.

1989-01-01

Monte Carlo simulation (without secondary radiation) of the standard photon interactions (Compton scattering, photoelectric absorption and pair protection) for the complex slab's geometry is used in numerical code ACCA. A typical ACCA run will yield: (a) transmission of primary photon radiation differential in energy, (b) the spectrum of energy deposited in the target as a function of position and (c) the cumulative percent energy deposition as a function of position. A cumulative percent energy deposition of photon monoenergetic beam incident on simplest and complexity tissue slab and Fe slab are presented in this paper. (author). 5 refs.; 2 figs

Study on the Deposition Rate Depending on Substrate Position by Using Ion Beam Sputtering Deposition

Energy Technology Data Exchange (ETDEWEB)

Kim, Yonggi; Kim, Bomsok; Lee, Jaesang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

Ion beams have been used for over thirty years to modify materials in manufacturing of integrated circuits, and improving the corrosion properties of surfaces. Recently, the requirements for ion beam processes are becoming especially challenging in the following areas : ultra shallow junction formation for LSI fabrication, low damage high rate ion beam sputtering and smoothing, high quality functional surface treatment for electrical and optical properties. Ion beam sputtering is an attractive technology for the deposition of thin film coatings onto a broad variety of polymer, Si-wafer, lightweight substrates. Demand for the decoration metal is increasing. In addition, lightweight of parts is important, because of energy issues in the industries. Although a lot of researches have been done with conventional PVD methods for the deposition of metal or ceramic films on the surface of the polymer, there are still adhesion problems.

Low energy Cu clusters slow deposition on a Fe (001) surface investigated by molecular dynamics simulation

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shixu [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Laboratory of Advanced Nuclear Materials, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Gong, Hengfeng [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Division of Nuclear Materials Science and Engineering, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Chen, Xuanzhi [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Li, Gongping, E-mail: ligp@lzu.edu.cn [School of Nuclear Science and Technology, Lanzhou University, Lanzhou 730000 (China); Wang, Zhiguang, E-mail: zhgwang@impcas.ac.cn [Laboratory of Advanced Nuclear Materials, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

2014-09-30

Highlights: • We study the deposition of low energy Cu clusters on Fe (001) surface by molecular dynamics. • The interaction between low energy cluster and substrate can be divided to the landing and the thermal diffusion phases. • The phenomenon of contact epitaxy of cluster occurred. • The thermal diffusion of cluster atoms was analyzed. - Abstract: The slow deposition of low energy Cu clusters on a Fe (001) surface was investigated by molecular dynamics simulation. A many-body potential based on Finnis–Sinclair model was used to describe the interactions among atoms. Three clusters comprising of 13, 55 and 147 atoms, respectively, were deposited with incident energies ranging from 0.0 to 1.0 eV/atom at various substrate temperatures (0, 300 and 800 K). The rearrangement and the diffusion of cluster can occur, only when the cluster atoms are activated and obtained enough migration energy. The interaction between low energy cluster and substrate can be divided to the landing and the thermal diffusion phases. In the former, the migration energy originates from the latent heat of binding energy for the soft deposition regime and primarily comes from the incident energy of cluster for the energetic cluster deposition regime. In the latter, the thermal vibration would result in some cluster atoms activated again at medium and high substrate temperatures. Also, the effects of incident energy, cluster size and substrate temperature on the interaction potential energy between cluster and substrate, the final deposition morphology of cluster, the spreading index and the structure parameter of cluster are analyzed.

Time-dependent theory of double ionization of helium under XUV radiation

International Nuclear Information System (INIS)

Nikolopoulos, L A A; Lambropoulos, P

2007-01-01

We present non-perturbative time-dependent calculations of single and double ionization of helium, under XUV radiation of photon energy ranging from 40 to 45 eV, through the direct propagation of the time-dependent Schroedinger equation. The time-dependent wavefunction of the atom under the field is expanded in terms of correlated multichannel states normalized with incoming-wave boundary conditions. In addition to presenting a new non-perturbative approach to the three-body problem, in a fully correlated scheme, capable of providing in the same calculation photoelectron energy and angularly resolved spectra, as well as cross sections through the lowest non-vanishing order transition amplitude, we also present a detailed comparison of the values of certain key quantities that have been obtained through a variety of other methods. The degree of agreement we find, while lending credence to the approach and its versatility, also highlights the remaining open questions in this novel context of double ionization

Energy deposition model for low-energy electrons (10-10 000 eV) in air

International Nuclear Information System (INIS)

Roldan, A.; Perez, J.M.; Williart, A.; Blanco, F.; Garcia, G.

2004-01-01

An energy deposition model for electrons in air that can be useful in microdosimetric applications is presented in this study. The model is based on a Monte Carlo simulation of the single electron scattering processes that can take place with the molecular constituents of the air in the energy range 10-10 000 eV. The input parameters for this procedure have been the electron scattering cross sections, both differential and integral. These parameters were calculated using a model potential method which describes the electron scattering with the molecular constituent of air. The reliability of the calculated integral cross section values has been evaluated by comparison with direct total electron scattering cross-section measurements performed by us in a transmission beam experiment. Experimental energy loss spectra for electrons in air have been used as probability distribution functions to define the electron energy loss in single collision events. The resulting model has been applied to simulate the electron transport through a gas cell containing air at different pressures and the results have been compared with those observed in the experiments. Finally, as an example of its applicability to dosimetric issues, the energy deposition of 10 000 eV by means of successive collisions in a free air chamber has been simulated

Time dependence of the field energy densities surrounding sources: Application to scalar mesons near point sources and to electromagnetic fields near molecules

International Nuclear Information System (INIS)

Persico, F.; Power, E.A.

1987-01-01

The time dependence of the dressing-undressing process, i.e., the acquiring or losing by a source of a boson field intensity and hence of a field energy density in its neighborhood, is considered by examining some simple soluble models. First, the loss of the virtual field is followed in time when a point source is suddenly decoupled from a neutral scalar meson field. Second, an initially bare point source acquires a virtual meson cloud as the coupling is switched on. The third example is that of an initially bare molecule interacting with the vacuum of the electromagnetic field to acquire a virtual photon cloud. In all three cases the dressing-undressing is shown to take place within an expanding sphere of radius r = ct centered at the source. At each point in space the energy density tends, for large times, to that of the ground state of the total system. Differences in the time dependence of the dressing between the massive scalar field and the massless electromagnetic field are discussed. The results are also briefly discussed in the light of Feinberg's ideas on the nature of half-dressed states in quantum field theory

Emission-energy dependence of ultrafast P-emission decay in ZnO from bulk to nanofilm

International Nuclear Information System (INIS)

Wakaiki, Shuji; Ichida, Hideki; Bamba, Motoaki; Kawase, Toshiki; Kawakami, Masaki; Mizoguchi, Kohji; Kim, DaeGwi; Nakayama, Masaaki; Kanematsu, Yasuo

2014-01-01

We have performed time-resolved photoluminescence (PL) spectroscopy for ZnO thin films with thicknesses of 90, 460, and 2800 nm under intense excitation condition. We clearly observed the P emission due to inelastic exciton–exciton scattering. It was found that, in the 460- and 2800-nm thick samples, the decay time of the P emission considerably depends on the detection energy inversely proportional to the group velocity of the polariton in a bulk crystal with each factor of proportionality. In contrast, the energy dependence is less remarkable in the 90-nm thick sample. The decay times are basically shortened with a decrease in the film thickness. The thickness dependence of the P-emission-decay profiles is explained by considering the crossover from the polariton modes in the 2800-nm thick sample (bulk-like film) to the exciton-/photon-like modes in the 90-nm thick sample (nanofilm). - Highlights: • We clearly observed the P-PL dynamics due to inelastic exciton–exciton scattering. • The P-PL decay times are basically shortened with a decrease in the film thickness. • The P-PL decay time depends on the detection energy in the bulk-like sample. • The energy dependence of the P-PL decay time almost disappears in the 90-nm sample. • The thickness dependence is explained by the crossover between exciton and photon

Emission-energy dependence of ultrafast P-emission decay in ZnO from bulk to nanofilm

Energy Technology Data Exchange (ETDEWEB)

Wakaiki, Shuji, E-mail: s.wakaiki@mls.eng.osaka-u.ac.jp [Department of Material and Life Science, Division of Advanced Science and Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Ichida, Hideki [Department of Material and Life Science, Division of Advanced Science and Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Science and Technology Entrepreneurship Laboratory, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Bamba, Motoaki [Department of Physics, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Kawase, Toshiki; Kawakami, Masaki [Department of Applied Physics, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Mizoguchi, Kohji [Department of Physical Science, Graduate School of Science, Osaka Prefecture University, 1-1 Gakuen, Naka-ku, Sakai, Osaka 599-8531 (Japan); Kim, DaeGwi; Nakayama, Masaaki [Department of Applied Physics, Graduate School of Engineering, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Kanematsu, Yasuo [Department of Material and Life Science, Division of Advanced Science and Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Science and Technology Entrepreneurship Laboratory, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan)

2014-08-01

We have performed time-resolved photoluminescence (PL) spectroscopy for ZnO thin films with thicknesses of 90, 460, and 2800 nm under intense excitation condition. We clearly observed the P emission due to inelastic exciton–exciton scattering. It was found that, in the 460- and 2800-nm thick samples, the decay time of the P emission considerably depends on the detection energy inversely proportional to the group velocity of the polariton in a bulk crystal with each factor of proportionality. In contrast, the energy dependence is less remarkable in the 90-nm thick sample. The decay times are basically shortened with a decrease in the film thickness. The thickness dependence of the P-emission-decay profiles is explained by considering the crossover from the polariton modes in the 2800-nm thick sample (bulk-like film) to the exciton-/photon-like modes in the 90-nm thick sample (nanofilm). - Highlights: • We clearly observed the P-PL dynamics due to inelastic exciton–exciton scattering. • The P-PL decay times are basically shortened with a decrease in the film thickness. • The P-PL decay time depends on the detection energy in the bulk-like sample. • The energy dependence of the P-PL decay time almost disappears in the 90-nm sample. • The thickness dependence is explained by the crossover between exciton and photon.

Interaction of protons with the C{sub 60} molecule: calculation of deposited energies and electronic stopping cross sections (v{sub {<=}}5 au)

Energy Technology Data Exchange (ETDEWEB)

Moretto-Capelle, P. [Laboratoire CAR, IRSAMC, UMR 5589 CNRS, Universite Paul Sabatier, Toulouse (France)]. E-mail: pmc@irsamc.ups-tlse.fr; Bordenave-Montesquieu, D.; Rentenier, A.; Bordenave-Montesquieu, A. [Laboratoire CAR, IRSAMC, UMR 5589 CNRS, Universite Paul Sabatier, Toulouse (France)

2001-09-28

The energy deposited by a proton in a C{sub 60} molecule is calculated over a broad collision velocity range from 0.1 to 5 au, using the free-electron gas model of Lindhard and Winther (1964 Mat. Fys. Medd. K Dan. Vidensk. Selsk. 34) and the C{sub 60} electron density distribution calculated by Puska and Nieminen. The energy lost by the proton is maximum near 1.8 au collision velocity in contrast with the saturation found in the low-velocity regime, in the 0.25-0.5 au velocity range, by Kunert and Schmidt. From the impact parameter dependence we deduce the distributions of deposited energies, the averaged energy losses and the C{sub 60} electronic stopping cross sections. It is found that the C{sub 60} molecule behaves as a carbon foil giving very similar absolute stopping cross sections per atom. (author). Letter-to-the-editor.

US oil dependency and energy security; Dependance petroliere et securite energetique americaine

Energy Technology Data Exchange (ETDEWEB)

Noel, P [Institut francais des Relations Internationals, 75 - Paris (France); [Universite Pierre Mendes-France-IEPE-CNRS, 38 - Grenoble (France)

2002-07-01

The three papers of this document were written in the framework of a seminar organized the 30 may 2002 by the IFRI in the framework of its program Energy and Climatic Change. The first presentation deals with the american oil policy since 1980 (relation between the oil dependence and the energy security, the Reagan oil policy, the new oil policy facing the increase of the dependence). The second one deals with the US energy security (oil security, domestic energy security, policy implications). The last presentation is devoted to the US oil dependence in a global context and the problems and policies of international energy security. (A.L.B.)

Role of renewable energy policies in energy dependency in Finland: System dynamics approach

International Nuclear Information System (INIS)

Aslani, Alireza; Helo, Petri; Naaranoja, Marja

2014-01-01

Highlights: • A system dynamics model for evaluating renewable energy policies on dependency is proposed. • The model considers the role of diversification on dependency and security of energy supply in Finland. • Dependency on imported sources will decrease depends on the defined scenarios in Finland. - Abstract: Objective: We discuss the role of diversification on dependency and security of energy supply. A system dynamics model with especial focus on the role of renewable energy resources (as a portfolio) on Finland’s energy dependency is developed. The purpose is also to cover a part of research gap exists in the system dynamics modeling of energy security investigations. Methods: A causal loops diagram and a system dynamics model evaluate Finnish scenarios of renewable energy policies. The analysis describes the relationship between dynamic factors such as RE encouragement packages, dependency, and energy demand. Results: A causal loops diagram and a system dynamics model evaluate three different Finnish scenarios of renewable energy policies by 2020. Conclusion: Analysis shows that despite 7% electricity/heat consumption growth by 2020 in Finland, dependency on imported sources will decrease between 1% and 7% depend on the defined scenarios. Practice Implications: The proposed model not only helps decision makers to test their scenarios related to renewable energy polices, it can be implemented by other countries

Energy dependence of polymer gels in the orthovoltage energy range

Directory of Open Access Journals (Sweden)

Yvonne Roed

2014-03-01

Full Text Available Purpose: Ortho-voltage energies are often used for treatment of patients’ superficial lesions, and also for small- animal irradiations. Polymer-Gel dosimeters such as MAGAT (Methacrylic acid Gel and THPC are finding increasing use for 3-dimensional verification of radiation doses in a given treatment geometry. For mega-voltage beams, energy dependence of MAGAT has been quoted as nearly energy-independent. In the kilo-voltage range, there is hardly any literature to shade light on its energy dependence.Methods: MAGAT was used to measure depth-dose for 250 kVp beam. Comparison with ion-chamber data showed a discrepancy increasing significantly with depth. An over-response as much as 25% was observed at a depth of 6 cm.Results and Conclusion: Investigation concluded that 6 cm water in the beam resulted in a half-value-layer (HVL change from 1.05 to 1.32 mm Cu. This amounts to an effective-energy change from 81.3 to 89.5 keV. Response measurements of MAGAT at these two energies explained the observed discrepancy in depth-dose measurements. Dose-calibration curves of MAGAT for (i 250 kVp beam, and (ii 250 kVp beam through 6 cm of water column are presented showing significant energy dependence.-------------------Cite this article as: Roed Y, Tailor R, Pinksy L, Ibbott G. Energy dependence of polymer gels in the orthovoltage energy range. Int J Cancer Ther Oncol 2014; 2(2:020232. DOI: 10.14319/ijcto.0202.32 

Electron transport in furfural: dependence of the electron ranges on the cross sections and the energy loss distribution functions

Science.gov (United States)

Ellis-Gibbings, L.; Krupa, K.; Colmenares, R.; Blanco, F.; Muńoz, A.; Mendes, M.; Ferreira da Silva, F.; Limá Vieira, P.; Jones, D. B.; Brunger, M. J.; García, G.

2016-09-01

Recent theoretical and experimental studies have provided a complete set of differential and integral electron scattering cross section data from furfural over a broad energy range. The energy loss distribution functions have been determined in this study by averaging electron energy loss spectra for different incident energies and scattering angles. All these data have been used as input parameters for an event by event Monte Carlo simulation procedure to obtain the electron energy deposition patterns and electron ranges in liquid furfural. The dependence of these results on the input cross sections is then analysed to determine the uncertainty of the simulated values.

WC-Co coatings deposited by the electro-thermal chemical spray method

Energy Technology Data Exchange (ETDEWEB)

Zhitomirsky, V.N. [Tel Aviv Univ. (Israel). Faculty of Engineering; Wald, S.; Rabani, L.; Zoler, D. [Propulsion Physics Division, SOREQ NRC, 81800, Yavne (Israel); Factor, M.; Roman, I. [School of Applied Sciences, The Hebrew University, 91904, Jerusalem (Israel); Cuperman, S.; Bruma, C. [School of Physics and Astronomy, Tel-Aviv University, 69978, Tel-Aviv (Israel)

2000-10-02

A novel thermal spray technology - an electro-thermal chemical spray (ETCS) for producing hard coatings is presented. The experimental coating apparatus consists of a machine gun barrel, a cartridge containing the coating material in powder form, a solid propellant, and a plasma ignition system. The plasma ignition system produces plasma in pulsed mode to ignite the solid propellant. On ignition, the drag force exerted by the combustion gases accelerates the powder particles towards the substrate. Using the ETCS technique, the process of single-shot WC-Co coating deposition on stainless steel substrate was studied. The influence of process parameters (plasma energy, mass of the solid propellant and the coated powder, distance between the gun muzzle and the substrate) on the coating structure and some of its properties were investigated. It was shown that ECTS technique effectively deposited the WC-Co coating with deposition thicknesses of 100-200 {mu}m per shot, while deposition yield of {proportional_to}70% was attained. The WC-Co coatings consisted of carbide particles distributed in amorphous matrix. The powder particle velocity was found to depend on the solid propellant mass and was weakly dependent on the plasma energy, while the particle processing temperature was strongly dependent on the plasma energy and almost independent of the solid propellant mass. Whilst increasing the solid propellant mass from 5 to 7 g, the deposition rate and yield correspondingly increased. When increasing the plasma energy, the temperature of the powder particles increased, the average carbide particle size decreased and their shape became more rounded. The deposition yield and microhardness at first increased and then achieved saturation by increasing the plasma energy. (orig.)

Collision cross sections of N2 by H+ impact at keV energies within time-dependent density-functional theory

Science.gov (United States)

Yu, W.; Gao, C.-Z.; Zhang, Y.; Zhang, F. S.; Hutton, R.; Zou, Y.; Wei, B.

2018-03-01

We calculate electron capture and ionization cross sections of N2 impacted by the H+ projectile at keV energies. To this end, we employ the time-dependent density-functional theory coupled nonadiabatically to molecular dynamics. To avoid the explicit treatment of the complex density matrix in the calculation of cross sections, we propose an approximate method based on the assumption of constant ionization rate over the period of the projectile passing the absorbing boundary. Our results agree reasonably well with experimental data and semi-empirical results within the measurement uncertainties in the considered energy range. The discrepancies are mainly attributed to the inadequate description of exchange-correlation functional and the crude approximation for constant ionization rate. Although the present approach does not predict the experiments quantitatively for collision energies below 10 keV, it is still helpful to calculate total cross sections of ion-molecule collisions within a certain energy range.

Molecular Excitation Energies from Time-Dependent Density Functional Theory Employing Random-Phase Approximation Hessians with Exact Exchange.

Science.gov (United States)

Heßelmann, Andreas

2015-04-14

Molecular excitation energies have been calculated with time-dependent density-functional theory (TDDFT) using random-phase approximation Hessians augmented with exact exchange contributions in various orders. It has been observed that this approach yields fairly accurate local valence excitations if combined with accurate asymptotically corrected exchange-correlation potentials used in the ground-state Kohn-Sham calculations. The inclusion of long-range particle-particle with hole-hole interactions in the kernel leads to errors of 0.14 eV only for the lowest excitations of a selection of three alkene, three carbonyl, and five azabenzene molecules, thus surpassing the accuracy of a number of common TDDFT and even some wave function correlation methods. In the case of long-range charge-transfer excitations, the method typically underestimates accurate reference excitation energies by 8% on average, which is better than with standard hybrid-GGA functionals but worse compared to range-separated functional approximations.

Kinetic-energy induced smoothening and delay of epitaxial breakdown in pulsed-laser deposition

International Nuclear Information System (INIS)

Shin, Byungha; Aziz, Michael J.

2007-01-01

We have isolated the effect of kinetic energy of depositing species from the effect of flux pulsing during pulsed-laser deposition (PLD) on surface morphology evolution of Ge(001) homoepitaxy at low temperature (100 deg. C). Using a dual molecular beam epitaxy (MBE) PLD chamber, we compare morphology evolution from three different growth methods under identical experimental conditions except for the differing nature of the depositing flux: (a) PLD with average kinetic energy 300 eV (PLD-KE); (b) PLD with suppressed kinetic energy comparable to thermal evaporation energy (PLD-TH); and (c) MBE. The thicknesses at which epitaxial breakdown occurs are ranked in the order PLD-KE>MBE>PLD-TH; additionally, the surface is smoother in PLD-KE than in MBE. The surface roughness of the films grown by PLD-TH cannot be compared due to the early epitaxial breakdown. These results demonstrate convincingly that kinetic energy is more important than flux pulsing in the enhancement of epitaxial growth, i.e., the reduction in roughness and the delay of epitaxial breakdown

Nanostructured Electrodes Via Electrostatic Spray Deposition for Energy Storage System

KAUST Repository

Chen, C.

2014-10-02

Energy storage systems such as Li-ion batteries and supercapacitors are extremely important in today’s society, and have been widely used as the energy and power sources for portable electronics, electrical vehicles and hybrid electrical vehicles. A lot of research has focused on improving their performance; however, many crucial challenges need to be addressed to obtain high performance electrode materials for further applications. Recently, the electrostatic spray deposition (ESD) technique has attracted great interest to satisfy the goals. Due to its many advantages, the ESD technique shows promising prospects compared to other conventional deposition techniques. In this paper, our recent research outcomes related to the ESD derived anodes for Li-ion batteries and other applications is summarized and discussed.

Recent Development of Advanced Electrode Materials by Atomic Layer Deposition for Electrochemical Energy Storage.

Science.gov (United States)

Guan, Cao; Wang, John

2016-10-01

Electrode materials play a decisive role in almost all electrochemical energy storage devices, determining their overall performance. Proper selection, design and fabrication of electrode materials have thus been regarded as one of the most critical steps in achieving high electrochemical energy storage performance. As an advanced nanotechnology for thin films and surfaces with conformal interfacial features and well controllable deposition thickness, atomic layer deposition (ALD) has been successfully developed for deposition and surface modification of electrode materials, where there are considerable issues of interfacial and surface chemistry at atomic and nanometer scale. In addition, ALD has shown great potential in construction of novel nanostructured active materials that otherwise can be hardly obtained by other processing techniques, such as those solution-based processing and chemical vapor deposition (CVD) techniques. This review focuses on the recent development of ALD for the design and delivery of advanced electrode materials in electrochemical energy storage devices, where typical examples will be highlighted and analyzed, and the merits and challenges of ALD for applications in energy storage will also be discussed.

Energy deposition by heavy ions: additivity of kinetic and potential energy contributions in hillock formation on CaF2.

Science.gov (United States)

Wang, Y Y; Grygiel, C; Dufour, C; Sun, J R; Wang, Z G; Zhao, Y T; Xiao, G Q; Cheng, R; Zhou, X M; Ren, J R; Liu, S D; Lei, Y; Sun, Y B; Ritter, R; Gruber, E; Cassimi, A; Monnet, I; Bouffard, S; Aumayr, F; Toulemonde, M

2014-07-18

Modification of surface and bulk properties of solids by irradiation with ion beams is a widely used technique with many applications in material science. In this study, we show that nano-hillocks on CaF2 crystal surfaces can be formed by individual impact of medium energy (3 and 5 MeV) highly charged ions (Xe(22+) to Xe(30+)) as well as swift (kinetic energies between 12 and 58 MeV) heavy xenon ions. For very slow highly charged ions the appearance of hillocks is known to be linked to a threshold in potential energy (Ep) while for swift heavy ions a minimum electronic energy loss per unit length (Se) is necessary. With our results we bridge the gap between these two extreme cases and demonstrate, that with increasing energy deposition via Se the Ep-threshold for hillock production can be lowered substantially. Surprisingly, both mechanisms of energy deposition in the target surface seem to contribute in an additive way, which can be visualized in a phase diagram. We show that the inelastic thermal spike model, originally developed to describe such material modifications for swift heavy ions, can be extended to the case where both kinetic and potential energies are deposited into the surface.

Interaction region design driven by energy deposition

Science.gov (United States)

Martin, Roman; Besana, Maria Ilaria; Cerutti, Francesco; Langner, Andy; Tomás, Rogelio; Cruz-Alaniz, Emilia; Dalena, Barbara

2017-08-01

The European Strategy Group for High Energy Physics recommends to study collider designs for the post-LHC era. Among the suggested projects there is the circular 100 TeV proton-proton collider FCC-hh. Starting from LHC and its proposed upgrade HL-LHC, this paper outlines the development of the interaction region design for FCC-hh. We identify energy deposition from debris of the collision events as a driving factor for the layout and draft the guiding principles to unify protection of the superconducting final focus magnets from radiation with a high luminosity performance. Furthermore, we offer a novel strategy to mitigate the lifetime limitation of the first final focus magnet due to radiation load, the Q1 split.

New applications with time-dependent thermochemical simulation

Energy Technology Data Exchange (ETDEWEB)

Koukkari, P. [VTT Chemical Technology, Espoo (Finland); Laukkanen, L. [VTT Automation, Espoo (Finland); Penttilae, K. [Kemira Engineering Oy, Helsinki (Finland)

1996-12-31

A new method (RATEMIX) to calculate multicomponent chemical reaction mixtures as a series of sequential thermochemical states was recently introduced. The procedure combines multicomponent thermodynamics with chemical kinetics and may be used to simulate the multicomponent reactors as a thermochemical natural process. The method combines the desired reaction rates sequentially with constrained Gibbs energy minimization. The reactant concentrations are determined by the experimental (Arrhenius) rate laws. During the course of the given reaction the subsequent side reactions are supposed to occur reversibly. At every sequential stage of the given reaction the temperature and composition of the reaction mixture are calculated by a thermodynamic subroutine, which minimizes the Gibbs energy of the system and takes into account the heat transfer between the system and its surroundings. The extents of reaction are included as algorithmic constraints in the Gibbs energy minimization procedure. Initially, the reactants are introduced to the system as inert copies to match both the mass and energy balance of the reactive system. During the calculation the copies are sequentially interchanged to the actual reactants which allows one to simulate the time-dependent reaction route by using the thermochemical procedure. For each intermediate stage, the temperature and composition are calculated and as well numerical estimates of the thermodynamic functions are obtained. The method is applicable in processes where the core thermodynamic and kinetic data of the system are known and the time-dependent heat transfer data can either be measured or estimated by calculation. The method has been used to simulate e.g. high temperature flame reactions, zinc vapour oxidation and a counter-current rotary drum with chemical reactions. The procedure has today been tested with SOLGASMIX, CHEMSAGE and HSC programs. (author)

New applications with time-dependent thermochemical simulation

Energy Technology Data Exchange (ETDEWEB)

Koukkari, P [VTT Chemical Technology, Espoo (Finland); Laukkanen, L [VTT Automation, Espoo (Finland); Penttilae, K [Kemira Engineering Oy, Helsinki (Finland)

1997-12-31

A new method (RATEMIX) to calculate multicomponent chemical reaction mixtures as a series of sequential thermochemical states was recently introduced. The procedure combines multicomponent thermodynamics with chemical kinetics and may be used to simulate the multicomponent reactors as a thermochemical natural process. The method combines the desired reaction rates sequentially with constrained Gibbs energy minimization. The reactant concentrations are determined by the experimental (Arrhenius) rate laws. During the course of the given reaction the subsequent side reactions are supposed to occur reversibly. At every sequential stage of the given reaction the temperature and composition of the reaction mixture are calculated by a thermodynamic subroutine, which minimizes the Gibbs energy of the system and takes into account the heat transfer between the system and its surroundings. The extents of reaction are included as algorithmic constraints in the Gibbs energy minimization procedure. Initially, the reactants are introduced to the system as inert copies to match both the mass and energy balance of the reactive system. During the calculation the copies are sequentially interchanged to the actual reactants which allows one to simulate the time-dependent reaction route by using the thermochemical procedure. For each intermediate stage, the temperature and composition are calculated and as well numerical estimates of the thermodynamic functions are obtained. The method is applicable in processes where the core thermodynamic and kinetic data of the system are known and the time-dependent heat transfer data can either be measured or estimated by calculation. The method has been used to simulate e.g. high temperature flame reactions, zinc vapour oxidation and a counter-current rotary drum with chemical reactions. The procedure has today been tested with SOLGASMIX, CHEMSAGE and HSC programs. (author)

Time history of diesel particle deposition in cylindrical dielectric barrier discharge reactors

Energy Technology Data Exchange (ETDEWEB)

Talebizadeh, P.; Rahimzadeh, H., E-mail: rahimzad@aut.ac.ir [Amirkabir University of Technology, Department of Mechanical Engineering (Iran, Islamic Republic of); Ahmadi, G. [Clarkson University, Department of Mechanical and Aeronautical Engineering (United States); Brown, R. [Queensland University of Technology, Biofuel Engine Research Facility (Australia); Inthavong, K. [RMIT University, School of Aerospace, Mechanical and Manufacturing Engineering (Australia)

2016-12-15

Non-thermal plasma (NTP) treatment reactors have recently been developed for elimination of diesel particulate matter for reducing both the mass and number concentration of particles. The role of the plasma itself is obscured by the phenomenon of particle deposition on the reactor surface. Therefore, in this study, the Lagrangian particle transport model is used to simulate the dispersion and deposition of nano-particles in the range of 5 to 500 nm in a NTP reactor in the absence of an electric field. A conventional cylindrical dielectric barrier discharge reactor is selected for the analysis. Brownian diffusion, gravity and Saffman lift forces were included in the simulations, and the deposition efficiencies of different sized diesel particles were studied. The results show that for the studied particle diameters, the effect of Saffman lift is negligible and gravity only affects the motion of particles with a diameter of 500 nm or larger. Time histories of particle transport and deposition were evaluated for one-time injection and a continuous (multiple-time) injection. The results show that the number of deposited particles for one-time injection is identical to the number of deposited particles for multiple-time injections when adjusted with the shift in time. Furthermore, the maximum number of escaped particles occurs at 0.045 s after the injection for all particle diameters. The presented results show that some particle reduction previously ascribed to plasma treatment has ignored contributions from the surface deposition.

Time history of diesel particle deposition in cylindrical dielectric barrier discharge reactors

International Nuclear Information System (INIS)

Talebizadeh, P.; Rahimzadeh, H.; Ahmadi, G.; Brown, R.; Inthavong, K.

2016-01-01

Non-thermal plasma (NTP) treatment reactors have recently been developed for elimination of diesel particulate matter for reducing both the mass and number concentration of particles. The role of the plasma itself is obscured by the phenomenon of particle deposition on the reactor surface. Therefore, in this study, the Lagrangian particle transport model is used to simulate the dispersion and deposition of nano-particles in the range of 5 to 500 nm in a NTP reactor in the absence of an electric field. A conventional cylindrical dielectric barrier discharge reactor is selected for the analysis. Brownian diffusion, gravity and Saffman lift forces were included in the simulations, and the deposition efficiencies of different sized diesel particles were studied. The results show that for the studied particle diameters, the effect of Saffman lift is negligible and gravity only affects the motion of particles with a diameter of 500 nm or larger. Time histories of particle transport and deposition were evaluated for one-time injection and a continuous (multiple-time) injection. The results show that the number of deposited particles for one-time injection is identical to the number of deposited particles for multiple-time injections when adjusted with the shift in time. Furthermore, the maximum number of escaped particles occurs at 0.045 s after the injection for all particle diameters. The presented results show that some particle reduction previously ascribed to plasma treatment has ignored contributions from the surface deposition.

Energy dependence of sputtering yields of Be, Be-C and Be-W films by Be{sup +}-ions

Energy Technology Data Exchange (ETDEWEB)

Korshunov, S.N.; Guseva, M.I.; Gureev, V.M.; Neumoin, V.E.; Stoljarova, V.G. [Russian Research Center Kurchatov Inst., Moscow (Russian Federation)

1998-01-01

The energy dependence measurements of Be, Be-C and Be-W deposited layer sputtering yields by Be{sup +}-ions were performed. The ion energy was varied in the range (0.3-5.0) keV. The temperature in the process of irradiation was sustained at the level of 670 K. The mixed layers were prepared by simultaneous sputtering of pair targets, Be and C, Be and W, and Be-targets with Ar{sup +}- and Be{sup +}-ions and codeposition of the sputtered atoms on silicon collectors The codeposited layer thickness was changed in the range of (500-1000) nm. The content of oxigen in the Be, Be-C, Be-W deposited layers did not exceed 20 at.%. The mixed layer sputtering yields were compared with the experimental and calculated data, obtained for the self-sputtering yields of beryllium and carbon. It was found that the sputtering yields of the Be-C and Be deposited layers by Be{sup +}-ions in the energy range (0.3-5.0) keV are within the range between the corresponding self-sputtering yields for Be and C. The sputtering yields for the mixture Be-W are close to the corresponding self-sputtering yields of beryllium. (author)

Time-dependent approach to collisional ionization using exterior complex scaling

International Nuclear Information System (INIS)

McCurdy, C. William; Horner, Daniel A.; Rescigno, Thomas N.

2002-01-01

We present a time-dependent formulation of the exterior complex scaling method that has previously been used to treat electron-impact ionization of the hydrogen atom accurately at low energies. The time-dependent approach solves a driven Schroedinger equation, and scales more favorably with the number of electrons than the original formulation. The method is demonstrated in calculations for breakup processes in two dimensions (2D) and three dimensions for systems involving short-range potentials and in 2D for electron-impact ionization in the Temkin-Poet model for electron-hydrogen atom collisions

Time-dependent Autler-Townes spectroscopy

International Nuclear Information System (INIS)

Qamar, Sajid; Zhu, S.-Y.; Zubairy, M Suhail

2003-01-01

Autler-Townes spontaneous emission spectroscopy is revisited for a time-dependent case. We report the results of spontaneous emission spectra for nonstationary scattered light signals using the definition of the time-dependent physical spectrum. This is a rare example of problems where time-dependent spectra can be calculated exactly

Time-dependent Autler-Townes spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Qamar, Sajid [Institute for Quantum Studies, Department of Physics, Texas A and M University, College Station, TX 77843-4242 (United States); Zhu, S.-Y. [Institute for Quantum Studies, Department of Physics, Texas A and M University, College Station, TX 77843-4242 (United States); Zubairy, M Suhail [Institute for Quantum Studies, Department of Physics, Texas A and M University, College Station, TX 77843-4242 (United States)

2003-04-01

Autler-Townes spontaneous emission spectroscopy is revisited for a time-dependent case. We report the results of spontaneous emission spectra for nonstationary scattered light signals using the definition of the time-dependent physical spectrum. This is a rare example of problems where time-dependent spectra can be calculated exactly.

Time-dependent behavior of concrete

International Nuclear Information System (INIS)

Pfeiffer, P.A.; Tanabe, Tada-aki

1992-01-01

This paper is a condensed version of the material presented at the International Workshop on Finite Element Analysis of Reinforced Concrete, Session 4 -- Time Dependent Behavior, held at Columbia University, New York on June 3--6, 1991. Dr. P.A. Pfeiffer presented recent developments in time-dependent behavior of concrete and Professor T. Tanabe presented a review of research in Japan on time-dependent behavior of concrete. The paper discusses the recent research of time-dependent behavior of concrete in the past few years. 6 refs

Dependence of Optical Properties of SEL-Deposited Silver Gallium Selenide Thin Films on the On-Line Growth Parameter: Annealing Duration

International Nuclear Information System (INIS)

Bhuiyan, M.R.A.; Firoz Hasan, S.M.

2005-01-01

Silver gallium selenide (AGS) composite thin films were formed onto ultrasonically and chemically cleaned glass substrates by successive on-line thermal evaporation of individual elements and post-deposition annealing at 300 0 C for various durations in vacuum. The annealing duration was varied between 5 and 20 minutes. The structural and optical properties of the films were ascertained by x-ray diffraction (XRD) and uv-vis-nir spectrophotometry (photon wavelength ranging between 300 and 2500 nm), respectively. The diffractogram indicated that these films were polycrystalline in nature having tetragonal structure with lattice parameters, a ∼ 6.0034 A and c ∼ 10.9165 A. The optical transmittance and reflectance were utilized to compute the absorption coefficient, refractive index and energy gap of the films. Dependence of the optical and structural properties of the films on various annealing durations has been analyzed. The nature of the optical transitions has been direct allowed with band gap energies ranging between 1.713 and 1.757 eV and refractive indices between 1.596 and 3.351 depending on photon energy as well as annealing duration. (authors)

Flow-dependent directional growth of carbon nanotube forests by chemical vapor deposition

International Nuclear Information System (INIS)

Kim, Hyeongkeun; Park, Young Chul; Chun, Kyoung-Yong; Kim, Young-Jin; Choi, Jae-Boong; Kim, Keun Soo; Kang, Junmo; Hong, Byung Hee; Boo, Jin-Hyo

2011-01-01

We demonstrated that the structural formation of vertically aligned carbon nanotube (CNT) forests is primarily affected by the geometry-related gas flow, leading to the change of growth directions during the chemical vapor deposition (CVD) process. By varying the growing time, flow rate, and direction of the carrier gas, the structures and the formation mechanisms of the vertically aligned CNT forests were carefully investigated. The growth directions of CNTs are found to be highly dependent on the nonlinear local gas flows induced by microchannels. The angle of growth significantly changes with increasing gas flows perpendicular to the microchannel, while the parallel gas flow shows almost no effect. A computational fluid dynamics (CFD) model was employed to explain the flow-dependent growth of CNT forests, revealing that the variation of the local pressure induced by microchannels is an important parameter determining the directionality of the CNT growth. We expect that the present method and analyses would provide useful information to control the micro- and macrostructures of vertically aligned CNTs for various structural/electrical applications.

Flow-dependent directional growth of carbon nanotube forests by chemical vapor deposition

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyeongkeun; Park, Young Chul; Chun, Kyoung-Yong; Kim, Young-Jin; Choi, Jae-Boong [School of Mechanical Engineering, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Kim, Keun Soo; Kang, Junmo; Hong, Byung Hee [SKKU Advanced Institute of Nanotechnology (SAINT) and Center for Human Interface Nano Technology (HINT), Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of); Boo, Jin-Hyo, E-mail: byunghee@skku.edu, E-mail: boong33@skku.edu [Department of Chemistry, RIAN and Institute of Basic Science, Sungkyunkwan University, Suwon, 440-746 (Korea, Republic of)

2011-03-04

We demonstrated that the structural formation of vertically aligned carbon nanotube (CNT) forests is primarily affected by the geometry-related gas flow, leading to the change of growth directions during the chemical vapor deposition (CVD) process. By varying the growing time, flow rate, and direction of the carrier gas, the structures and the formation mechanisms of the vertically aligned CNT forests were carefully investigated. The growth directions of CNTs are found to be highly dependent on the nonlinear local gas flows induced by microchannels. The angle of growth significantly changes with increasing gas flows perpendicular to the microchannel, while the parallel gas flow shows almost no effect. A computational fluid dynamics (CFD) model was employed to explain the flow-dependent growth of CNT forests, revealing that the variation of the local pressure induced by microchannels is an important parameter determining the directionality of the CNT growth. We expect that the present method and analyses would provide useful information to control the micro- and macrostructures of vertically aligned CNTs for various structural/electrical applications.

Nuclear three-body problem and energy-dependent potentials

International Nuclear Information System (INIS)

Abdurakhmanov, A.; Akhmadkhodzhaev, B.; Zubarev, A.L.; Irgaziev, B.F.

1985-01-01

Energy-dependent potentials in the three-body problem are being considered. Three-particle equations for the case of pairing energy-dependent potentials are generalized and the problems related to this ambiguous generalization are investigated. In terms of the equations obtained the tritium binding energy and vertex coupling constants (Tdn) and (Tdν) are evaluated. The binding energy and, especially, coupling constants are shown to be sensitive to a shape of the energy-dependent potential

Dependences of deposition rate and OH content on concentration of added trichloroethylene in low-temperature silicon oxide films deposited using silicone oil and ozone gas

Science.gov (United States)

Horita, Susumu; Jain, Puneet

2018-03-01

We investigated the dependences of the deposition rate and residual OH content of SiO2 films on the concentration of trichloroethylene (TCE), which was added during deposition at low temperatures of 160-260 °C with the reactant gases of silicone oil (SO) and O3. The deposition rate depends on the TCE concentration and is minimum at a concentration of ˜0.4 mol/m3 at 200 °C. The result can be explained by surface and gas-phase reactions. Experimentally, we also revealed that the thickness profile is strongly affected by gas-phase reaction, in which the TCE vapor was blown directly onto the substrate surface, where it mixed with SO and O3. Furthermore, it was found that adding TCE vapor reduces residual OH content in the SiO2 film deposited at 200 °C because TCE enhances the dehydration reaction.

Energy deposition at the bone-tissue interface from nuclear fragments produced by high-energy nucleons

Science.gov (United States)

Cucinotta, Francis A.; Hajnal, Ferenc; Wilson, John W.

1990-01-01

The transport of nuclear fragmentation recoils produced by high-energy nucleons in the region of the bone-tissue interface is considered. Results for the different flux and absorbed dose for recoils produced by 1 GeV protons are presented in a bidirectional transport model. The energy deposition in marrow cavities is seen to be enhanced by recoils produced in bone. Approximate analytic formulae for absorbed dose near the interface region are also presented for a simplified range-energy model.

Cluster formation in precompound nuclei in the time-dependent framework

Science.gov (United States)

Schuetrumpf, B.; Nazarewicz, W.

2017-12-01

Background: Modern applications of nuclear time-dependent density functional theory (TDDFT) are often capable of providing quantitative description of heavy ion reactions. However, the structures of precompound (preequilibrium, prefission) states produced in heavy ion reactions are difficult to assess theoretically in TDDFT as the single-particle density alone is a weak indicator of shell structure and cluster states. Purpose: We employ the time-dependent nucleon localization function (NLF) to reveal the structure of precompound states in nuclear reactions involving light and medium-mass ions. We primarily focus on spin saturated systems with N =Z . Furthermore, we study reactions with oxygen and carbon ions, for which some experimental evidence for α clustering in precompound states exists. Method: We utilize the symmetry-free TDDFT approach with the Skyrme energy density functional UNEDF1 and compute the time-dependent NLFs to describe 16O + 16O,40Ca + 16O, 40Ca + 40Ca, and O,1816 + 12C collisions at energies above the Coulomb barrier. Results: We show that NLFs reveal a variety of time-dependent modes involving cluster structures. For instance, the 16O + 16O collision results in a vibrational mode of a quasimolecular α - 12C - 12C-α state. For heavier ions, a variety of cluster configurations are predicted. For the collision of O,1816 + 12C, we showed that the precompound system has a tendency to form α clusters. This result supports the experimental findings that the presence of cluster structures in the projectile and target nuclei gives rise to strong entrance channel effects and enhanced α emission. Conclusion: The time-dependent nucleon localization measure is a very good indicator of cluster structures in complex precompound states formed in heavy-ion fusion reactions. The localization reveals the presence of collective vibrations involving cluster structures, which dominate the initial dynamics of the fusing system.

Equivalence between deep energy-dependent and shallow angular momentum dependent potentials

International Nuclear Information System (INIS)

Fiedeldey, H.; Sofianos, S.A.; Papastylianos, A.; Amos, K.A.; Allen, L.J.

1989-01-01

Recently Baye showed that supersymmetry can be applied to determine a shallow l-dependent potential phase equivalent to a deep potential, assumed to be energy-independent and have Panli forbidden states (PFS), for α-α scattering. The PFS are eliminated by this procedure. Such deep potentials are generated as equivalent local potentials (ELP) to the Resonating Group Model (RGM) and are generally energy-dependent. To eliminate this E-dependence as required for the application of Baye's method, l-dependent, but E-independent, deep local potentials were generated by the exact inversion method of Marchenko. Subsequently, the supersymmetric method was used to eliminate the PFS, ensuring that the generalized Levinson theorem is satisfied. As an example, the method was applied to the simple model of two dineutrons scattering in the RGM, where the deep ELP of Horiuchi has a substantial energy-dependence and one PFS only for l=O. 16 refs., 5 figs

A Complete Reporting of MCNP6 Validation Results for Electron Energy Deposition in Single-Layer Extended Media for Source Energies <= 1-MeV

Energy Technology Data Exchange (ETDEWEB)

Dixon, David A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hughes, Henry Grady [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-05-04

In this paper, we expand on previous validation work by Dixon and Hughes. That is, we present a more complete suite of validation results with respect to to the well-known Lockwood energy deposition experiment. Lockwood et al. measured energy deposition in materials including beryllium, carbon, aluminum, iron, copper, molybdenum, tantalum, and uranium, for both single- and multi-layer 1-D geometries. Source configurations included mono-energetic, mono-directional electron beams with energies of 0.05-MeV, 0.1-MeV, 0.3- MeV, 0.5-MeV, and 1-MeV, in both normal and off-normal angles of incidence. These experiments are particularly valuable for validating electron transport codes, because they are closely represented by simulating pencil beams incident on 1-D semi-infinite slabs with and without material interfaces. Herein, we include total energy deposition and energy deposition profiles for the single-layer experiments reported by Lockwood et al. (a more complete multi-layer validation will follow in another report).

Range-separated time-dependent density-functional theory with a frequency-dependent second-order Bethe-Salpeter correlation kernel

Energy Technology Data Exchange (ETDEWEB)

Rebolini, Elisa, E-mail: elisa.rebolini@kjemi.uio.no; Toulouse, Julien, E-mail: julien.toulouse@upmc.fr [Laboratoire de Chimie Théorique, Sorbonne Universités, UPMC Univ Paris 06, CNRS, 4 place Jussieu, F-75005 Paris (France)

2016-03-07

We present a range-separated linear-response time-dependent density-functional theory (TDDFT) which combines a density-functional approximation for the short-range response kernel and a frequency-dependent second-order Bethe-Salpeter approximation for the long-range response kernel. This approach goes beyond the adiabatic approximation usually used in linear-response TDDFT and aims at improving the accuracy of calculations of electronic excitation energies of molecular systems. A detailed derivation of the frequency-dependent second-order Bethe-Salpeter correlation kernel is given using many-body Green-function theory. Preliminary tests of this range-separated TDDFT method are presented for the calculation of excitation energies of the He and Be atoms and small molecules (H{sub 2}, N{sub 2}, CO{sub 2}, H{sub 2}CO, and C{sub 2}H{sub 4}). The results suggest that the addition of the long-range second-order Bethe-Salpeter correlation kernel overall slightly improves the excitation energies.

Experimental investigation on the energy deposition and morphology of the electrical explosion of copper wire in vacuum

International Nuclear Information System (INIS)

Shi, Zongqian; Shi, Yuanjie; Wang, Kun; Jia, Shenli

2016-01-01

This paper presents the experimental results of the electrical explosion of copper wires in vacuum using negative nanosecond-pulsed current with magnitude of 1–2 kA. The 20 μm-diameter copper wires with different lengths are exploded with three different current rates. A laser probe is applied to construct the shadowgraphy and interferometry diagnostics to investigate the distribution and morphology of the exploding product. The interference phase shift is reconstructed from the interferogram, by which the atomic density distribution is calculated. Experimental results show that there exist two voltage breakdown modes depending on the amount of the specific energy deposition. For the strong-shunting mode, shunting breakdown occurs, leading to the short-circuit-like current waveform. For the weak-shunting mode with less specific energy deposition, the plasma generated during the voltage breakdown is not enough to form a conductive plasma channel, resulting in overdamped declining current waveform. The influence of the wire length and current rate on the characteristics of the exploding wires is also analyzed.

Experimental investigation on the energy deposition and morphology of the electrical explosion of copper wire in vacuum

Energy Technology Data Exchange (ETDEWEB)

Shi, Zongqian; Shi, Yuanjie; Wang, Kun; Jia, Shenli [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Shanxi 710049 (China)

2016-03-15

This paper presents the experimental results of the electrical explosion of copper wires in vacuum using negative nanosecond-pulsed current with magnitude of 1–2 kA. The 20 μm-diameter copper wires with different lengths are exploded with three different current rates. A laser probe is applied to construct the shadowgraphy and interferometry diagnostics to investigate the distribution and morphology of the exploding product. The interference phase shift is reconstructed from the interferogram, by which the atomic density distribution is calculated. Experimental results show that there exist two voltage breakdown modes depending on the amount of the specific energy deposition. For the strong-shunting mode, shunting breakdown occurs, leading to the short-circuit-like current waveform. For the weak-shunting mode with less specific energy deposition, the plasma generated during the voltage breakdown is not enough to form a conductive plasma channel, resulting in overdamped declining current waveform. The influence of the wire length and current rate on the characteristics of the exploding wires is also analyzed.

Fricke xylenol gel energy dependence

International Nuclear Information System (INIS)

Costa, Rosangela T.; Moreira, Marcos V.; Almeida, Adelaide de

2009-01-01

The advancement of technology has increasingly use the of ionizing radiation mainly in the areas of medicine, industry and research. The development of instruments and methods for an effective performance for detection and measurement of each radiation area was crucial. The literature have demonstrated the effectiveness of the Fricke Xylenol Gel (FXG) as an adequate chemical sensor to be used for dosimetry, once its effective atomic number and density are near to those of the soft tissue. The use of photon beams for therapeutic purpose requires knowledge of their characteristics that can vary for each equipment. Therefore, is important to know all parameters involved for the patient irradiation as the total geometry involved, type of radiation, target material composition and beam energy, that have to be taken into account in the beam dosimetry for the treatment success being the energy parameter is one of the most important. This work was developed to study the energetic dependence of the FXG dosimeter. This chemical solution is made with gelatine 300 Bloom, ferrous ammonium sulfate, xylenol orange, sulfuric acid and Milli-Q water and is based on the Fe +2 oxidation to Fe +3 , due to the ionizing radiation leading to the xylenol orange - ferric complex formation, that is linear depend on the absorbed dose. The FXG samples were irradiated with photons of different energies and the absorbance measurements were done with the spectrophotometric technique at the 585 nm, FXG highest absorption peak. The energetic dependence results presented a stronger dependence for low energies and almost independence for high energies, as expected by the interaction of radiation with matter. (author)

Lateral particle density reconstruction from the energy deposits of particles in the KASCADE-Grande detector stations

International Nuclear Information System (INIS)

Toma, G.; Brancus, I.M.; Mitrica, B.; Sima, O.; Rebel, H.

2005-01-01

The study of primary cosmic rays with energies greater than 10 14 eV is done mostly by indirect observation techniques such as the study of Extensive Air Showers (EAS). In the much larger framework effort of inferring data on the mass and energy of the primaries from EAS observables, the present study aims at delivering a versatile method and software tool that will be used to reconstruct lateral particle densities from the energy deposits of particles in the KASCADE-Grande detector stations. The study has been performed on simulated events, by taking into account the interaction of the EAS components with the detector array (energy deposits). The energy deposits have been parametrized for different incident energies and angles. Thus it is possible to reconstruct the particle densities in detectors from the energy deposits. A correlation between lateral particle density and primary mass and primary energy (at ∼ 600 m from shower core) has been established. The study puts great emphasis on the quality of reconstruction and also on the speed of the technique. The data obtained from the study on simulated events will be used soon on real events detected by the KASCADE-Grande array. (authors)

Structural properties of WO{sub 3} dependent of the annealing temperature deposited by hot-filament metal oxide deposition

Energy Technology Data Exchange (ETDEWEB)

Flores M, J. E. [Benemerita Universidad Autonoma de Puebla, Facultad de Ciencias de la Electronica, Av. San Claudio y 18 Sur, Ciudad Universitaria, Col. Jardines de San Manuel, 72570 Puebla (Mexico); Diaz R, J. [IPN, Centro de Investigacion en Biotecnologia Aplicada, Ex-Hacienda de San Molino Km 1.5 Tepetitla, 90700 Tlaxcala (Mexico); Balderas L, J. A., E-mail: eflores@ece.buap.mx [IPN, Unidad Profesional Interdisciplinaria de Biotecnologia, Av. Acueducto s/n, Col. Barrio la Laguna, 07340 Mexico D. F. (Mexico)

2012-07-01

In this work presents a study of the effect of the annealing temperature on structural and optical properties of WO{sub 3} that has been grown by hot-filament metal oxide deposition. The chemical stoichiometry was determined by X-ray photoelectron spectroscopy. By X-ray diffraction obtained that the as-deposited WO{sub 3} films present mainly monoclinic crystalline phase. WO{sub 3} optical band gap energy can be varied from 2.92 to 3.15 eV obtained by transmittance measurements by annealing WO{sub 3} from 100 to 500 C. The Raman spectrum of the as-deposited WO{sub 3} film shows four intense peaks that are typical Raman peaks of crystalline WO{sub 3} (m-phase) that corresponds to the stretching vibrations of the bridging oxygen that are assigned to W-O stretching ({upsilon}) and W-O bending ({delta}) modes, respectively, which enhanced and increased their intensity with the annealing temperature. (Author)

Real time process algebra with time-dependent conditions

NARCIS (Netherlands)

Baeten, J.C.M.; Middelburg, C.A.

We extend the main real time version of ACP presented in [6] with conditionals in which the condition depends on time. This extension facilitates flexible dependence of proccess behaviour on initialization time. We show that the conditions concerned generalize the conditions introduced earlier

Dependable Real-Time Systems

Science.gov (United States)

1991-09-30

0196 or 413 545-0720 PI E-mail Address: krithi@nirvan.cs.umass.edu, stankovic(ocs.umass.edu Grant or Contract Title: Dependable Real - Time Systems Grant...Dependable Real - Time Systems " Grant or Contract Number: N00014-85-k-0398 L " Reporting Period: 1 Oct 87 - 30 Sep 91 , 2. Summary of Accomplishments ’ 2.1 Our...in developing a sound approach to scheduling tasks in complex real - time systems , (2) developed a real-time operating system kernel, a preliminary

Holographic complexity for time-dependent backgrounds

Energy Technology Data Exchange (ETDEWEB)

Momeni, Davood, E-mail: davoodmomeni78@gmail.com [Eurasian International Center for Theoretical Physics and Department of General Theoretical Physics, Eurasian National University, Astana 010008 (Kazakhstan); Faizal, Mir, E-mail: mirfaizalmir@googlemail.com [Irving K. Barber School of Arts and Sciences, University of British Columbia, Okanagan, 3333 University Way, Kelowna, British Columbia V1V 1V7 (Canada); Department of Physics and Astronomy, University of Lethbridge, Lethbridge, Alberta, T1K 3M4 (Canada); Bahamonde, Sebastian, E-mail: sebastian.beltran.14@ucl.ac.uk [Department of Mathematics, University College London, Gower Street, London, WC1E 6BT (United Kingdom); Myrzakulov, Ratbay [Eurasian International Center for Theoretical Physics and Department of General Theoretical Physics, Eurasian National University, Astana 010008 (Kazakhstan)

2016-11-10

In this paper, we will analyze the holographic complexity for time-dependent asymptotically AdS geometries. We will first use a covariant zero mean curvature slicing of the time-dependent bulk geometries, and then use this co-dimension one spacelike slice of the bulk spacetime to define a co-dimension two minimal surface. The time-dependent holographic complexity will be defined using the volume enclosed by this minimal surface. This time-dependent holographic complexity will reduce to the usual holographic complexity for static geometries. We will analyze the time-dependence as a perturbation of the asymptotically AdS geometries. Thus, we will obtain time-dependent asymptotically AdS geometries, and we will calculate the holographic complexity for such time-dependent geometries.

High energy ion range and deposited energy calculation using the Boltzmann-Fokker-Planck splitting of the Boltzmann transport equation

International Nuclear Information System (INIS)

Mozolevski, I.E.

2001-01-01

We consider the splitting of the straight-ahead Boltzmann transport equation in the Boltzmann-Fokker-Planck equation, decomposing the differential cross-section into a singular part, corresponding to small energy transfer events, and in a regular one, which corresponds to large energy transfer. The convergence of implantation profile, nuclear and electronic energy depositions, calculated from the Boltzmann-Fokker-Planck equation, to the respective exact distributions, calculated from Monte-Carlo method, was exanimate in a large-energy interval for various values of splitting parameter and for different ion-target mass relations. It is shown that for the universal potential there exists an optimal value of splitting parameter, for which range and deposited energy distributions, calculated from the Boltzmann-Fokker-Planck equation, accurately approximate the exact distributions and which minimizes the computational expenses

Time-dependent crashworthiness of polyurethane foam

Science.gov (United States)

Basit, Munshi Mahbubul; Cheon, Seong Sik

2018-05-01

Time-dependent stress-strain relationship as well as crashworthiness of polyurethane foam was investigated under constant impact energy with different velocities, considering inertia and strain-rate effects simultaneously during the impact testing. Even though the impact energies were same, the percentage in increase in densification strain due to higher impact velocities was found, which yielded the wider plateau region, i.e. growth in crashworthiness. This phenomenon is analyzed by the microstructure of polyurethane foam obtained from scanning electron microscopy. The equations, coupled with the Sherwood-Frost model and the impulse-momentum theory, were employed to build the constitutive equation of the polyurethane foam and calculate energy absorption capacity of the foam. The nominal stress-strain curves obtained from the constitutive equation were compared with results from impact tests and were found to be in good agreement. This study is dedicated to guiding designer use polyurethane foam in crashworthiness structures such as an automotive bumper system by providing crashworthiness data, determining the crush mode, and addressing a mathematical model of the crashworthiness.

Interaction region design driven by energy deposition

Directory of Open Access Journals (Sweden)

Roman Martin

2017-08-01

Full Text Available The European Strategy Group for High Energy Physics recommends to study collider designs for the post-LHC era. Among the suggested projects there is the circular 100 TeV proton-proton collider FCC-hh. Starting from LHC and its proposed upgrade HL-LHC, this paper outlines the development of the interaction region design for FCC-hh. We identify energy deposition from debris of the collision events as a driving factor for the layout and draft the guiding principles to unify protection of the superconducting final focus magnets from radiation with a high luminosity performance. Furthermore, we offer a novel strategy to mitigate the lifetime limitation of the first final focus magnet due to radiation load, the Q1 split.

Erosion of pyrolytic carbon under high surface energy deposition from a pulsed hydrogen plasma

International Nuclear Information System (INIS)

Bolt, H.

1992-01-01

Carbon materials are widely applied as plasma facing materials in nuclear fusion devices and are also the prime candidate materials for the next generation of experimental fusion reactors. During operation these materials are frequently subjected to high energy deposition from plasma disruptions. The erosion of carbon materials is regarded as the main issue governing the operational lifetime of plasma facing components. Laboratory experiments have been performed to study the thermal erosion behaviour of carbon in a plasma environment. In the experiments the surface of pyrolytic carbon specimens was exposed to pulsed energy deposition of up to 3.8 MJ m -2 from a hydrogen plasma. The behaviour of the eroded carbon species in the plasma was measured by time-resolved and space-resolved spectroscopy. Intense line radiation of ionic carbon has been measured in the plasma in front of the carbon surface. The results show that the eroded carbon is immediately ionised in the vicinity of the material surface, with a fraction of it being ionised to the double-charged state. (Author)

Stabilizing laser energy density on a target during pulsed laser deposition of thin films

Science.gov (United States)

Dowden, Paul C.; Jia, Quanxi

2016-05-31

A process for stabilizing laser energy density on a target surface during pulsed laser deposition of thin films controls the focused laser spot on the target. The process involves imaging an image-aperture positioned in the beamline. This eliminates changes in the beam dimensions of the laser. A continuously variable attenuator located in between the output of the laser and the imaged image-aperture adjusts the energy to a desired level by running the laser in a "constant voltage" mode. The process provides reproducibility and controllability for deposition of electronic thin films by pulsed laser deposition.

Photodetachment of the H− ion in a linear time-dependent electric field

International Nuclear Information System (INIS)

Wang, De-Hua; Chen, Zhaohang; Cheng, Shaohao

2016-01-01

Using the time-dependent closed orbit theory, we study the photodetachment of the H − ion in a linear time-dependent electric field for the first time. An analytical formula for calculating the time-dependent photodetachment cross section of this system has been put forward. It is found when the external electric field changes very slowly with time, there is only one closed orbit of the detached electron and the photodetachment cross section is quite stable. However, when the electric field changes quickly with time, three different types of closed orbits are found and the photodetachment cross section oscillates in a much more complex way. The connection of each type of closed orbit with the oscillatory structure in the photodetachment cross section is analyzed quantitatively. In addition, the photon energy and the laser field parameters can also have great influence on the time-dependent photodetachment cross section of this system. This study provides a clear and intuitive picture for the photodetachment dynamics of a negative ion in the presence of a time-dependent electric field and may guide future experimental studies exploring the quantum effect in the photodetachment dynamics of negative ions from a time-dependent viewpoint. (paper)

Student understanding of time dependence in quantum mechanics

Directory of Open Access Journals (Sweden)

Paul J. Emigh

2015-09-01

Full Text Available [This paper is part of the Focused Collection on Upper Division Physics Courses.] The time evolution of quantum states is arguably one of the more difficult ideas in quantum mechanics. In this article, we report on results from an investigation of student understanding of this topic after lecture instruction. We demonstrate specific problems that students have in applying time dependence to quantum systems and in recognizing the key role of the energy eigenbasis in determining the time dependence of wave functions. Through analysis of student responses to a set of four interrelated tasks, we categorize some of the difficulties that underlie common errors. The conceptual and reasoning difficulties that have been identified are illustrated through student responses to four sets of questions administered at different points in a junior-level course on quantum mechanics. Evidence is also given that the problems persist throughout undergraduate instruction and into the graduate level.

Topic 5: Time-Dependent Behavior

International Nuclear Information System (INIS)

Pfeiffer, P.A.; Tanabe, Tada-aki

1991-01-01

This chapter is a report of the material presented at the International Workshop on Finite Element Analysis of Reinforced Concrete, Session 4 -- Time Dependent Behavior, held at Columbia University, New York on June 3--6, 1991. Dr. P.A. Pfeiffer presented recent developments in time-dependent behavior of concrete and Professor T. Tanabe presented a review of research in Japan on time-dependent behavior of concrete. The chapter discusses the recent research of time-dependent behavior of concrete in the past few years in both the USA-European and Japanese communities. The author appreciates the valuable information provided by Zdenek P. Bazant in preparing the USA-European Research section

Simulation calculation for the energy deposition profile and the transmission fraction of intense pulsed electron beam at various incident angles

International Nuclear Information System (INIS)

Yang Hailiang; Qiu Aici; Zhang Jiasheng; Huang Jianjun; Sun Jianfeng

2002-01-01

The incident angles have a heavy effect on the intense pulsed electron beam energy deposition profile, energy deposition fraction and beam current transmission fraction in material. The author presents electron beam energy deposition profile and energy deposition fraction versus electron energy (0.5-2.0 MeV), at various incident angles for three aluminum targets of various thickness via theoretical calculation. The intense pulsed electron beam current transmission fractions versus electron energy (0.4-1.4 MeV) at various incident angles for three thickness of carbon targets were also theoretically calculated. The calculation results indicate that the deposition energy in unit mass of material surface layer increase with the rise of electron beam incident angle, and electron beam with low incident angle (closer to normal incident angle) penetrates deeper into the target material. The electron beams deposit more energy in unit mass of material surface layer at 60 degree-70 degree incident angle

Hydrodynamic perspective on memory in time-dependent density-functional theory

International Nuclear Information System (INIS)

Thiele, M.; Kuemmel, S.

2009-01-01

The adiabatic approximation of time-dependent density-functional theory is studied in the context of nonlinear excitations of two-electron singlet systems. We compare the exact time evolution of these systems to the adiabatically exact one obtained from time-dependent Kohn-Sham calculations relying on the exact ground-state exchange-correlation potential. Thus, we can show under which conditions the adiabatic approximation breaks down and memory effects become important. The hydrodynamic formulation of quantum mechanics allows us to interpret these results and relate them to dissipative effects in the Kohn-Sham system. We show how the breakdown of the adiabatic approximation can be inferred from the rate of change of the ground-state noninteracting kinetic energy.

Time-dependent friction and solvation time correlation function

International Nuclear Information System (INIS)

Samanta, Alok; Ali, Sk Musharaf; Ghosh, Swapan K

2005-01-01

We have derived a new relation between the time-dependent friction and solvation time correlation function (STCF) for non-polar fluids. The friction values calculated using this relation and simulation results on STCF for a Lennard-Jones fluid are shown to have excellent agreement with the same obtained through mode-coupling theory. Also derived is a relation between the time-dependent dielectric friction and STCF for polar fluids. Routes are thus provided to obtain the time-dependent friction (non-polar as well as dielectric) from an experimentally measured quantity like STCF, even if the interparticle interaction potential is not known

High energy resolution and first time-dependent positron annihilation induced Auger electron spectroscopty

Energy Technology Data Exchange (ETDEWEB)

Mayer, Jakob

2010-04-03

It was the aim of this thesis to improve the existing positron annihilation induced Auger spectrometer at the highly intense positron source NEPOMUC (NEutron induced POsitron source MUniCh) in several ways: Firstly, the measurement time for a single spectrum should be reduced from typically 12 h to roughly 1 h or even less. Secondly, the energy resolution, which amounted to {delta}E/E{approx}10%, should be increased by at least one order of magnitude in order to make high resolution positron annihilation induced Auger spectroscopy (PAES)-measurements of Auger transitions possible and thus deliver more information about the nature of the Auger process. In order to achieve these objectives, the PAES spectrometer was equipped with a new electron energy analyzer. For its ideal operation all other components of the Auger analysis chamber had to be adapted. Particularly the sample manipulation and the positron beam guidance had to be renewed. Simulations with SIMION {sup registered} ensured the optimal positron lens parameters. After the adjustment of the new analyzer and its components, first measurements illustrated the improved performance of the PAES setup: Firstly, the measurement time for short overview measurements was reduced from 3 h to 420 s. The measurement time for more detailed Auger spectra was shortened from 12 h to 80 min. Secondly, even with the reduced measurement time, the signal to noise ratio was also enhanced by one order of magnitude. Finally, the energy resolution was improved to {delta}E/E < 1. The exceptional surface sensitivity and elemental selectivity of PAES was demonstrated in measurements of Pd and Fe, both coated with Cu layers of varying thickness. PAES showed that with 0.96 monolayer of Cu on Fe, more than 55% of the detected Auger electrons stem from Cu. In the case of the Cu coated Pd sample 0.96 monolayer of Cu resulted in a Cu Auger fraction of more than 30% with PAES and less than 5% with electron induced Auger spectroscopy

Energy relaxation and separation of a hot electron-hole pair in organic aggregates from a time-dependent wavepacket diffusion method

International Nuclear Information System (INIS)

Han, Lu; Liang, WanZhen; Zhao, Yi; Zhong, Xinxin

2014-01-01

The time-dependent wavepacket diffusive method [X. Zhong and Y. Zhao, J. Chem. Phys. 138, 014111 (2013)] is extended to investigate the energy relaxation and separation of a hot electron-hole pair in organic aggregates with incorporation of Coulomb interaction and electron-phonon coupling. The pair initial condition generated by laser pulse is represented by a Gaussian wavepacket with a central momentum. The results reveal that the hot electron energy relaxation is very well described by two rate processes with the fast rate much larger than the slow one, consistent with experimental observations, and an efficient electron-hole separation is accomplished accompanying the fast energy relaxation. Furthermore, although the extra energy indeed helps the separation by overcoming the Coulomb interaction, the width of initial wavepacket is much sensitive to the separation efficiency and the narrower wavepacket generates the more separated charges. This behavior may be useful to understand the experimental controversy of the hot carrier effect on charge separation

Time Dependent Quantum Mechanics

OpenAIRE

Morrison, Peter G.

2012-01-01

We present a systematic method for dealing with time dependent quantum dynamics, based on the quantum brachistochrone and matrix mechanics. We derive the explicit time dependence of the Hamiltonian operator for a number of constrained finite systems from this formalism. Once this has been achieved we go on to calculate the wavevector as a function of time, in order to demonstrate the use of matrix methods with respect to several concrete examples. Interesting results are derived for elliptic ...

Noisy time-dependent spectra

International Nuclear Information System (INIS)

Shore, B.W.; Eberly, J.H.

1983-01-01

The definition of a time-dependent spectrum registered by an idealized spectrometer responding to a time-varying electromagnetic field as proposed by Eberly and Wodkiewicz and subsequently applied to the spectrum of laser-induced fluorescence by Eberly, Kunasz, and Wodkiewicz is here extended to allow a stochastically fluctuating (interruption model) environment: we provide an algorithm for numerical determination of the time-dependent fluorescence spectrum of an atom subject to excitation by an intense noisy laser and interruptive relaxation

Incident energy dependence of pt correlations at relativistic energies

CERN Document Server

Adams, J; Ahammed, Z; Amonett, J; Anderson, B D; Arkhipkin, D; Averichev, G S; Badyal, S K; Bai, Y; Balewski, J; Barannikova, O; Barnby, L S; Baudot, J; Bekele, S; Belaga, V V; Bellingeri-Laurikainen, A; Bellwied, R; Berger, J; Bezverkhny, B I; Bharadwaj, S; Bhasin, A; Bhati, A K; Bhatia, V S; Bichsel, H; Bielcik, J; Bielcikova, J; Billmeier, A; Bland, L C; Blyth, C O; Bonner, B E; Botje, M; Boucham, A; Bouchet, J; Brandin, A V; Bravar, A; Bystersky, M; Cadman, R V; Cai, X Z; Caines, H; Calderón de la Barca-Sanchez, M; Castillo, J; Catu, O; Cebra, D; Chajecki, Z; Chaloupka, P; Chattopadhyay, S; Chen, H F; Chen, Y; Cheng, J; Cherney, M; Chikanian, A; Christie, W; Coffin, J P; Cormier, T M; Cramer, J G; Crawford, H J; Das, D; Das, S; Daugherity, M; De Moura, M M; Dedovich, T G; Derevshchikov, A A; Didenko, L; Dietel, T; Dogra, S M; Dong, W J; Dong, X; Draper, J E; Du, F; Dubey, A K; Dunin, V B; Dunlop, J C; Dutta, M R; Mazumdar; Eckardt, V; Edwards, W R; Efimov, L G; Emelianov, V; Engelage, J; Eppley, G; Erazmus, B; Estienne, M; Fachini, P; Faivre, J; Fatemi, R; Fedorisin, J; Filimonov, K; Filip, P; Finch, E; Fine, V; Fisyak, Yu; Fu, J; Gagliardi, C A; Gaillard, L; Gans, J; Ganti, M S; Geurts, F; Ghazikhanian, V; Ghosh, P; González, J E; Gos, H; Grachov, O; Grebenyuk, O; Grosnick, D P; Guertin, S M; Guo, Y; Sen-Gupta, A; Gutíerrez, T D; Hallman, T J; Hamed, A; Hardtke, D; Harris, J W; Heinz, M; Henry, T W; Hepplemann, S; Hippolyte, B; Hirsch, A; Hjort, E; Hoffmann, G W; Huang, H Z; Huang, S L; Hughes, E W; Humanic, T J; Igo, G; Ishihara, A; Jacobs, P; Jacobs, W W; Jedynak, M; Jiang, H; Jones, P G; Judd, E G; Kabana, S; Kang, K; Kaplan, M; Keane, D; Kechechyan, A; Khodyrev, V Yu; Kiryluk, J; Kisiel, A; Kislov, E M; Klay, J; Klein, S R; Koetke, D D; Kollegger, T; Kopytine, M; Kotchenda, L; Kowalik, K L; Krämer, M; Kravtsov, P; Kravtsov, V I; Krüger, K; Kuhn, C; Kulikov, A I; Kumar, A; Kutuev, R K; Kuznetsov, A A; Lamont, M A C; Landgraf, J M; Lange, S; Laue, F; Lauret, J; Lebedev, A; Lednicky, R; Lehocka, S; Le Vine, M J; Li, C; Li, Q; Li, Y; Lin, G; Lindenbaum, S J; Lisa, M A; Liu, F; Liu, H; Liu, L; Liu, Q J; Liu, Z; Ljubicic, T; Llope, W J; Long, H; Longacre, R S; López-Noriega, M; Love, W A; Lu, Y; Ludlam, T; Lynn, D; Ma, G L; Ma, J G; Ma, Y G; Magestro, D; Mahajan, S; Mahapatra, D P; Majka, R; Mangotra, L K; Manweiler, R; Margetis, S; Markert, C; Martin, L; Marx, J N; Matis, H S; Matulenko, Yu A; McClain, C J; McShane, T S; Meissner, F; Melnik, Yu M; Meschanin, A; Miller, M L; Minaev, N G; Mironov, C; Mischke, A; Mishra, D K; Mitchell, J; Mohanty, B; Molnár, L; Moore, C F; Morozov, D A; Munhoz, M G; Nandi, B K; Nayak, S K; Nayak, T K; Nelson, J M; Netrakanti, P K; Nikitin, V A; Nogach, L V; Nurushev, S B; Odyniec, Grazyna Janina; Ogawa, A; Okorokov, V; Oldenburg, M; Olson, D; Pal, S K; Panebratsev, Yu A; Panitkin, S Y; Pavlinov, A I; Pawlak, T; Peitzmann, T; Perevozchikov, V; Perkins, C; Peryt, W; Petrov, V A; Phatak, S C; Picha, R; Planinic, M; Pluta, J; Porile, N; Porter, J; Poskanzer, A M; Potekhin, M V; Potrebenikova, E V; Potukuchi, B V K S; Prindle, D; Pruneau, C A; Putschke, J; Rakness, G; Raniwala, R; Raniwala, S; Ravel, O; Ray, R L; Razin, S V; Reichhold, D M; Reid, J G; Reinnarth, J; Renault, G; Retière, F; Ridiger, A; Ritter, H G; Roberts, J B; Rogachevski, O V; Romero, J L; Rose, A; Roy, C; Ruan, L; Russcher, M; Sahoo, R; Sakrejda, I; Salur, S; Sandweiss, J; Sarsour, M; Savin, I; Sazhin, P S; Schambach, J; Scharenberg, R P; Schmitz, N; Schweda, K; Seger, J; Seyboth, P; Shahaliev, E; Shao, M; Shao, W; Sharma, M; Shen, W Q; Shestermanov, K E; Shimansky, S S; Sichtermann, E P; Simon, F; Singaraju, R N; Smirnov, N; Snellings, R; Sood, G; Sørensen, P; Sowinski, J; Speltz, J; Spinka, H M; Srivastava, B; Stadnik, A; Stanislaus, T D S; Stock, R; Stolpovsky, A; Strikhanov, M N; Stringfellow, B C; Suaide, A A P; Sugarbaker, E R; Suire, C; Sumbera, M; Surrow, B; Swanger, M; Symons, T J M; Szanto de Toledo, A; Tai, A; Takahashi, J; Tang, A H; Tarnowsky, T J; Thein, D; Thomas, J H; Timoshenko, S; Tokarev, M; Trentalange, S; Tribble, R E; Tsai, O D; Ulery, J; Ullrich, T; Underwood, D G; Van Buren, G; Van Leeuwen, M; Van der Molen, A M; Varma, R; Vasilevski, I M; Vasilev, A N; Vernet, R; Vigdor, S E; Viyogi, Y P; Vokal, S; Voloshin, S A; Waggoner, W T; Wang, F; Wang, G; Wang, X L; Wang, Y; Wang, Z M; Ward, H; Watson, J W; Webb, J C; Westfall, G D; Wetzler, A; Whitten, C; Wieman, H; Wissink, S W; Witt, R; Wood, J; Wu, J; Xu, N; Xu, Z; Xu, Z Z; Yamamoto, E; Yepes, P; Yurevich, V I; Zborovský, I; Zhang, H; Zhang, W M; Zhang, Y; Zhang, Z P; Zoulkarneev, R; Zoulkarneeva, Y; Zubarev, A N

2005-01-01

We present results for two-particle transverse momentum correlations, , as a function of event centrality for Au+Au collisions at sqrt(sNN) = 20, 62, 130, and 200 GeV at the Relativistic Heavy Ion Collider. We observe correlations decreasing with centrality that are similar at all four incident energies. The correlations multiplied by the multiplicity density increase with incident energy and the centrality dependence may show evidence of processes such as thermalization, minijet production, or the saturation of transverse flow. The square root of the correlations divided by the event-wise average transverse momentum per event shows little or no beam energy dependence and generally agrees with previous measurements at the Super Proton Synchrotron.

Microstructure of ZnO thin films deposited by high power impulse magnetron sputtering

Energy Technology Data Exchange (ETDEWEB)

Reed, A.N., E-mail: amber.reed.5@us.af.mil [Materials and Manufacturing Directorate, Air Force Research Laboratory, 3005 Hobson Way, Wright Patterson Air Force Base, OH 45433 (United States); Department of Chemical and Materials Engineering, University of Dayton, Dayton, OH 45469 (United States); Shamberger, P.J. [Department of Materials Science and Engineering, Texas A& M University, College Station, TX 77843 (United States); Hu, J.J. [Materials and Manufacturing Directorate, Air Force Research Laboratory, 3005 Hobson Way, Wright Patterson Air Force Base, OH 45433 (United States); University of Dayton Research Institute, University of Dayton, Dayton, OH 45469 (United States); Muratore, C. [Department of Chemical and Materials Engineering, University of Dayton, Dayton, OH 45469 (United States); Bultman, J.E. [Materials and Manufacturing Directorate, Air Force Research Laboratory, 3005 Hobson Way, Wright Patterson Air Force Base, OH 45433 (United States); University of Dayton Research Institute, University of Dayton, Dayton, OH 45469 (United States); Voevodin, A.A., E-mail: andrey.voevodin@us.af.mil [Materials and Manufacturing Directorate, Air Force Research Laboratory, 3005 Hobson Way, Wright Patterson Air Force Base, OH 45433 (United States)

2015-03-31

High power impulse magnetron sputtering was used to deposit thin (~ 100 nm) zinc oxide (ZnO) films from a ceramic ZnO target onto substrates heated to 150 °C. The resulting films had strong crystallinity, highly aligned (002) texture and low surface roughness (root mean square roughness less than 10 nm), as determined by X-ray diffraction, transmission electron microscopy, scanning electron microscopy and atomic force spectroscopy measurements. Deposition pressure and target–substrate distance had the greatest effect on film microstructure. The degree of alignment in the films was strongly dependent on the gas pressure. Deposition at pressures less than 0.93 Pa resulted in a bimodal distribution of grain sizes. An initial growth layer with preferred orientations (101) and (002) parallel to the interface was observed at the film–substrate interface under all conditions examined here; the extent of that competitive region was dependent on growth conditions. Time-resolved current measurements of the target and ion energy distributions, determined using energy resolved mass spectrometry, were correlated to film microstructure in order to investigate the effect of plasma conditions on film nucleation and growth. - Highlights: • Low temperature growth of nanocrystalline zinc oxide (ZnO) films. • ZnO films had a highly (002) textured, smooth, dense microstructure. • Dominant (002) orientation of films was pressure dependent. • Interfacial (101)/(002) mixed orientation layer controlled by substrate location.

High energy resolution and first time-dependent positron annihilation induced Auger electron spectroscopty

International Nuclear Information System (INIS)

Mayer, Jakob

2010-01-01

It was the aim of this thesis to improve the existing positron annihilation induced Auger spectrometer at the highly intense positron source NEPOMUC (NEutron induced POsitron source MUniCh) in several ways: Firstly, the measurement time for a single spectrum should be reduced from typically 12 h to roughly 1 h or even less. Secondly, the energy resolution, which amounted to ΔE/E∼10%, should be increased by at least one order of magnitude in order to make high resolution positron annihilation induced Auger spectroscopy (PAES)-measurements of Auger transitions possible and thus deliver more information about the nature of the Auger process. In order to achieve these objectives, the PAES spectrometer was equipped with a new electron energy analyzer. For its ideal operation all other components of the Auger analysis chamber had to be adapted. Particularly the sample manipulation and the positron beam guidance had to be renewed. Simulations with SIMION registered ensured the optimal positron lens parameters. After the adjustment of the new analyzer and its components, first measurements illustrated the improved performance of the PAES setup: Firstly, the measurement time for short overview measurements was reduced from 3 h to 420 s. The measurement time for more detailed Auger spectra was shortened from 12 h to 80 min. Secondly, even with the reduced measurement time, the signal to noise ratio was also enhanced by one order of magnitude. Finally, the energy resolution was improved to ΔE/E 2,3 VV-transition with PAES. Thus, within this thesis two objectives were achieved: Firstly, the PAES spectrometer was renewed and improved by at least one order of magnitude with respect to the signal to noise ratio, the measurement time and the energy resolution. Secondly, several measurements have been carried out, demonstrating the high performance of the spectrometer. Amongst them are first dynamic PAES measurements and a high resolution measurement of the CuM 2,3 VV

Electrophoretic Deposition as a New Bioactive Glass Coating Process for Orthodontic Stainless Steel

OpenAIRE

Kyotaro Kawaguchi; Masahiro Iijima; Kazuhiko Endo; Itaru Mizoguchi

2017-01-01

This study investigated the surface modification of orthodontic stainless steel using electrophoretic deposition (EPD) of bioactive glass (BG). The BG coatings were characterized by spectrophotometry, scanning electron microscopy with energy dispersive X-ray spectrometry, and X-ray diffraction. The frictional properties were investigated using a progressive load scratch test. The remineralization ability of the etched dental enamel was studied according to the time-dependent mechanical proper...

Dependence of energy per molecule on sputtering yields with reactive gas cluster ions

International Nuclear Information System (INIS)

Toyoda, Noriaki; Yamada, Isao

2010-01-01

Gas cluster ions show dense energy deposition on a target surface, which result in the enhancement of chemical reactions. In reactive sputtering with gas cluster ions, the energy per atom or molecule plays an important role. In this study, the average cluster size (N, the number of atoms or molecules in a cluster ion) was controlled; thereby the dependences of the energy per molecule on the sputtering yields of carbon by CO 2 cluster ions and that of Si by SF 6 /Ar mixed gas cluster ions were investigated. Large CO 2 cluster ions with energy per molecule of 1 eV showed high reactive sputtering yield of an amorphous carbon film. However, these ions did not cause the formation of large craters on a graphite surface. It is possible to achieve very low damage etching by controlling the energy per molecule of reactive cluster ions. Further, in the case of SF 6 /Ar mixed cluster ions, it was found that reactive sputtering was enhanced when a small amount of SF 6 gas (∼10%) was mixed with Ar. The reactive sputtering yield of Si by one SF 6 molecule linearly increased with the energy per molecule.

Microdroplet deposition through a film-free laser forward printing technique

International Nuclear Information System (INIS)

Patrascioiu, A.; Fernández-Pradas, J.M.; Morenza, J.L.; Serra, P.

2012-01-01

Highlights: ► Circular droplets are obtained for a wide range of focusing depths at fixed energy. ► Focusing depth variation study reveals two abrupt transitions in droplet diameter. ► Liquid ejection mechanism is mediated by two types of jets of different origin. ► Evolution of jets depends on the focusing depth accounting for the seen transitions. - Abstract: A recently developed film-free laser forward microprinting technique allows printing transparent and weakly absorbing liquids with high resolution and reproducibility. Its operating principle consists in the tight focusing of ultrashort laser pulses inside the liquid, and near its free surface, such that all the laser energy is absorbed in a small region around the beam waist. A cavitation bubble is then created inside the liquid, whose subsequent expansion results into the ejection of liquid. The collection of the ejected liquid on a substrate leads to the deposition of micron-sized droplets. In this work, we investigate a relevant process parameter of the technique, namely the laser focusing depth, and its influence on the morphology of the deposited droplets. The study reveals that for a fixed laser pulse energy there exists a relatively wide range of focusing depths at which circular and uniform droplets can be printed. The process of liquid ejection is also investigated. Time-resolved images reveal that liquid ejection proceeds through the formation of two kinds of jets which display clearly differentiated dynamics, and which could provide an interpretation for the dependence observed between the morphology of the deposited droplets and the laser focusing depth.

Measurement of simulated lung deposition of radon daughters

International Nuclear Information System (INIS)

Jonassen, N.; Jensen, B.

1992-01-01

A measurement system for the lung deposition of radon daughters based on respiratory models was suggested by Hopke et al. By choosing suitable mesh size and flow velocities it is possible to design a multiple-wire screen sampler simulating deposition in the respiratory tract of aerosols over the size range 0.5-1000 nm. This paper describes a preliminary investigation where simulated deposition in the nasal tract and in the bronchii (for mouth breathing as well as nasal breathing) is determined. The measurements were performed in atmospheres where the normalised exposure rate (equilibrium factor) was varied by changing the aerosol loading of the air as well as by enhanced electrostatic plateout. The general results of the measurements are that the energy deposited in the nose with nasal breathing and in the bronchii with mouth breathing varies as the calculated dose while the energy deposited in the bronchii with nasal breathing follows the exposure. It is also demonstrated that the energy deposited for a fixed value of the radon concentration may vary by a factor of 2-7 depending on the treatment of the air. (author)

Scheduling with time-dependent execution times

NARCIS (Netherlands)

Woeginger, G.J.

1995-01-01

We consider systems of tasks where the task execution times are time-dependent and where all tasks have some common deadline. We describe how to compute in polynomial time a schedule that minimizes the number of late tasks. This answers a question raised in a recent paper by Ho, Leung and Wei.

Time-dependent Hartree-Fock dynamics and phase transition in Lipkin-Meshkov-Glick model

International Nuclear Information System (INIS)

Kan, K.; Lichtner, P.C.; Dworzecka, M.; Griffin, J.J.

1980-01-01

The time-dependent Hartree-Fock solutions of the two-level Lipkin-Meshkov-Glick model are studied by transforming the time-dependent Hartree-Fock equations into Hamilton's canonical form and analyzing the qualitative structure of the Hartree-Fock energy surface in the phase space. It is shown that as the interaction strength increases these time-dependent Hartree-Fock solutions undergo a qualitative change associated with the ground state phase transition previously studied in terms of coherent states. For two-body interactions stronger than the critical value, two types of time-dependent Hartree-Fock solutions (the ''librations'' and ''rotations'' in Hamilton's mechanics) exist simultaneously, while for weaker interactions only the rotations persist. It is also shown that the coherent states with the maximum total pseudospin value are determinants, so that time-dependent Hartree-Fock analysis is equivalent to the coherent state method

Time-dependent theoretical model of the polar wind: Preliminary results

International Nuclear Information System (INIS)

Gombosi, T.I.; Cravens, T.E.; Nagy, A.F.

1985-01-01

The coupled time dependent continuity, momentum and energy equations of a two ion (O + and H + ) quasineutral plasma were solved in order to extend our understanding of polar wind behavior. This numerical code allows studies of the time dependent behavior of polar wind-type flows into and out of the ionosphere. Initial studies indicate that the typical time constants for electron and ion temperature changes are of the order of minutes and tens of minutes, respectively. The response time of the minor high altitude ion O + is less than an hour, whereas that of the major ion, H + , is many hours. The initial test runs also demonstrate the fact that temporary supersonic flows of both O + and H + are possible, especially in the presence of significant ion heating

Tokamak power reactor ignition and time dependent fractional power operation

International Nuclear Information System (INIS)

Vold, E.L.; Mau, T.K.; Conn, R.W.

1986-06-01

A flexible time-dependent and zero-dimensional plasma burn code with radial profiles was developed and employed to study the fractional power operation and the thermal burn control options for an INTOR-sized tokamak reactor. The code includes alpha thermalization and a time-dependent transport loss which can be represented by any one of several currently popular scaling laws for energy confinement time. Ignition parameters were found to vary widely in density-temperature (n-T) space for the range of scaling laws examined. Critical ignition issues were found to include the extent of confinement time degradation by alpha heating, the ratio of ion to electron transport power loss, and effect of auxiliary heating on confinement. Feedback control of the auxiliary power and ion fuel sources are shown to provide thermal stability near the ignition curve

Measurements of poloidal and toroidal energy deposition asymmetries in the ASDEX divertors

International Nuclear Information System (INIS)

Evans, T.E.

1991-03-01

Energy deposition characteristics in the ASDEX divertors have been analyzed over a wide range of discharges and wall conditions during ohmically heated, additionally heated, or lower hybrid current drive experiments. Changes in discharge operating parameters with high power additional heating produce a diversity of effects on the magnitudes and distributions of the energy absorbed in the divertors. Poloidally and toroidally resolved energy deposition patterns are particularly sensitive to changes in the edge safety factor, the type and power level of additional heating used, and the vertical position of the plasma. In most additionally heated discharges, a large fraction of the incremental divertor loading is found on only one or two target rings. Poloidal in-out asymmetries, which typically favor the low-field side by a factor of 2.5 in ohmic discharges, commonly range between a factor of 2.5 and 4.5 in additionally heated experiments and in extreme cases can be as large as a factor of 5.6. At the same time, toroidal asymmetries on individual target rings are found to range between a factor of 1.4 and 3.8 in typical ICRH and NBI cases with extreme LHCD cases of 4.3. A model, proposed to explain the cause of discharge asymmetries, is compared with the experimental observations. Under some conditions, for example during LHCD experiments, the model is in good agreement with the data. A method is proposed for supressing discharge asymmetries which may generally improve the divertor performance as well. (orig./AH)

Palladium clusters deposited on the heterogeneous substrates

Energy Technology Data Exchange (ETDEWEB)

Wang, Kun, E-mail: cqdxwk@126.com [College of Power Engineering, Chongqing University, Chongqing 400044 (China); Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing 400044 (China); Liu, Juanfang, E-mail: juanfang@cqu.edu.cn [College of Power Engineering, Chongqing University, Chongqing 400044 (China); Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing 400044 (China); Chen, Qinghua, E-mail: qhchen@cqu.edu.cn [College of Power Engineering, Chongqing University, Chongqing 400044 (China); Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education of PRC, Chongqing 400044 (China)

2016-07-15

Graphical abstract: The site-exchange between the substrate and cluster atoms can result in the formation of the surface alloys and the reconstruction of the cluster structure before the collision system approaching the thermal equilibrium. The deposited cluster adjusted the atom arrangement as possibly as to match the substrate lattice arrangement from bottom to up. The structural reconstruction is accompanied by the system potential energy minimization. - Highlights: • The deposition process can divide explicitly into three stages: adsorption, collision, relaxation. • The local melt does not emerge inside the substrate during the deposition process. • Surface alloys are formed by the site-exchange between the cluster and substrate atoms. • The cluster reconstructs the atom arrangement following as the substrate lattice arrangement from bottom to up. • The structural reconstruction ability and scope depend on the cluster size and incident energy. - Abstract: To improve the performance of the Pd composite membrane prepared by the cold spraying technology, it is extremely essential to give insights into the deposition process of the cluster and the heterogeneous deposition of the big Pd cluster at the different incident velocities on the atomic level. The deposition behavior, morphologies, energetic and interfacial configuration were examined by the molecular dynamic simulation and characterized by the cluster flattening ratio, the substrate maximum local temperature, the atom-embedded layer number and the surface-alloy formation. According to the morphology evolution, three deposition stages and the corresponding structural and energy evolution were clearly identified. The cluster deformation and penetrating depth increased with the enhancement of the incident velocity, but the increase degree also depended on the substrate hardness. The interfacial interaction between the cluster and the substrate can be improved by the higher substrate local temperature

Measurement and Prediction of Time-independent and Time-dependent Rheological Behavior of Waxy Crude Oil

Directory of Open Access Journals (Sweden)

Yavar Karimi

2017-01-01

Full Text Available Wax deposition phenomenon changes the rheological behavior of waxy crude oil completely. In the current work, the rheological time-dependent and time-independent behaviors of waxy crude oil samples are studied and flow curve and compliance function are measured for the oil samples with various wax contents at different temperatures. A decrease in temperature and an increase in wax content lead to an increase in the viscosity and yield stress but a significant drop in compliance function. A modified Burger model is developed to predict the behavior of the compliance function and a modified Casson model is used to predict the flow curve of the waxy crude oil samples within a vast range of wax contents and temperatures. The proposed Burger and Casson models match with experimental results with R2 of 99.7% and 97.33% respectively.

Towards a climate-dependent paradigm of ammonia emission and deposition

Energy Technology Data Exchange (ETDEWEB)

Sutton, M.A.; Reis, S.; Riddick, S.N.; Dragosits, U.; Nemitz, E.; Tang, Y.S.; Braban, C.F.; Vieno, M.; Dore, A.J.; Mitchell, R.F.; Wanless, S.; Daunt, F.; Fowler, D. [NERC Centre for Ecology and Hydrology Edinburgh, Bush Estate, Penicuik EH26 0QB (United Kingdom); Blackall, T.D. [Department of Geography, Strand Campus, Kings College London, London WC2R 2LS (United Kingdom); Theobald, M.R. [Higher Technical School of Agricultural Engineering, Technical University of Madrid, Ciudad Universitaria s/n, 28040 Madrid (Spain); Milford, C. [Izana Atmospheric Research Center, Meteorological State Agency of Spain (AEMET), Santa Cruz de Tenerife 38071 (Spain); Flechard, C.R. [INRA, Agrocampus Ouest, UMR 1069 SAS, 65 rue de St. Brieuc, 35042 Rennes Cedex (France); Loubet, B.; Massad, R.; Cellier, P.; Personne, E. [UMR INRA-AgroParisTech Environnement et Grandes Cultures, 78850 Thiverval-Grignon (France); Coheur, P.F.; Clarisse, L.; Van Damme, M.; Ngadi, Y. [Spectroscopie de l' atmosphere, Chimie Quantique et Photophysique, Universite Libre de Bruxelles (ULB), 50 avenue F. D. Roosevelt, 1050 Brussels (Belgium); Clerbaux, C. [Universite Paris 06, Universite Versailles-St. Quentin, UMR8190, CNRS/INSU, LATMOS-IPSL, Paris (France); Geels, C.; Hertel, O. [Department of Environmental Science, Aarhus University, P.O. Box 358, Frederiksborgvej 399, 4000 Roskilde (Denmark); Ambelas Skjoeth, C. [National Pollen and Aerobiology Research Unit, University of Worcester, Henwick Grove, Worcester WR2 6AJ (United Kingdom); Wichink Kruit, R.J. [TNO, Climate, Air and Sustainability, P.O. Box 80015, 3508 TA Utrecht (Netherlands); Pinder, R.W.; Bash, J.O.; Walker, J.T. [US Environmental Protection Agency, Office of Research and Development, Research Triangle Park, 109 T.W. Alexander Drive, Durham, NC 27711 (United States); Simpson, D. [Norwegian Meteorological Institute, EMEP MSC-W, P.O. Box 43-Blindern, 0313 Oslo (Norway); Horvath, L. [Plant Ecology Research Group of Hungarian Academy of Sciences, Institute of Botany and Ecophysiology, Szent Istvan University, Pater K. utca 1, 2100 Goedoello (Hungary); Misselbrook, T.H. [Rothamsted Research, Sustainable Soils and Grassland Systems, North Wyke, Okehampton EX20 2SB (United Kingdom); Bleeker, A. [Energy Research Centre of the Netherlands (ECN), P.O. Box 1, 1755 ZG Petten (Netherlands); Dentener, F. [European Commission, DG Joint Research Centre, via Enrico Fermi 2749, 21027 Ispra (Italy); De Vries, W. [Alterra, Wageningen University and Research Centre, Droevendaalsesteeg 4, 6708 PB Wageningen (Netherlands)

2013-07-15

Existing descriptions of bi-directional ammonia (NH3) land-atmosphere exchange incorporate temperature and moisture controls, and are beginning to be used in regional chemical transport models. However, such models have typically applied simpler emission factors to upscale the main NH3 emission terms. While this approach has successfully simulated the main spatial patterns on local to global scales, it fails to address the environment- and climate-dependence of emissions. To handle these issues, we outline the basis for a new modelling paradigm where both NH3 emissions and deposition are calculated online according to diurnal, seasonal and spatial differences in meteorology. We show how measurements reveal a strong, but complex pattern of climatic dependence, which is increasingly being characterized using ground-based NH3 monitoring and satellite observations, while advances in process-based modelling are illustrated for agricultural and natural sources, including a global application for seabird colonies. A future architecture for NH3 emission-deposition modelling is proposed that integrates the spatio-temporal interactions, and provides the necessary foundation to assess the consequences of climate change. Based on available measurements, a first empirical estimate suggests that 5{sup o}C warming would increase emissions by 42 per cent (28-67%). Together with increased anthropogenic activity, global NH3 emissions may increase from 65 (45-85) Tg N in 2008 to reach 132 (89-179) Tg by 2100.

Time-Dependent Close-Coupling Methods for Electron-Atom/Molecule Scattering

International Nuclear Information System (INIS)

Colgan, James

2014-01-01

The time-dependent close-coupling (TDCC) method centers on an accurate representation of the interaction between two outgoing electrons moving in the presence of a Coulomb field. It has been extensively applied to many problems of electrons, photons, and ions scattering from light atomic targets. Theoretical Description: The TDCC method centers on a solution of the time-dependent Schrödinger equation for two interacting electrons. The advantages of a time-dependent approach are two-fold; one treats the electron-electron interaction essentially in an exact manner (within numerical accuracy) and a time-dependent approach avoids the difficult boundary condition encountered when two free electrons move in a Coulomb field (the classic three-body Coulomb problem). The TDCC method has been applied to many fundamental atomic collision processes, including photon-, electron- and ion-impact ionization of light atoms. For application to electron-impact ionization of atomic systems, one decomposes the two-electron wavefunction in a partial wave expansion and represents the subsequent two-electron radial wavefunctions on a numerical lattice. The number of partial waves required to converge the ionization process depends on the energy of the incoming electron wavepacket and on the ionization threshold of the target atom or ion.

A simple shear limited, single size, time dependent flocculation model

Science.gov (United States)

Kuprenas, R.; Tran, D. A.; Strom, K.

2017-12-01

This research focuses on the modeling of flocculation of cohesive sediment due to turbulent shear, specifically, investigating the dependency of flocculation on the concentration of cohesive sediment. Flocculation is important in larger sediment transport models as cohesive particles can create aggregates which are orders of magnitude larger than their unflocculated state. As the settling velocity of each particle is determined by the sediment size, density, and shape, accounting for this aggregation is important in determining where the sediment is deposited. This study provides a new formulation for flocculation of cohesive sediment by modifying the Winterwerp (1998) flocculation model (W98) so that it limits floc size to that of the Kolmogorov micro length scale. The W98 model is a simple approach that calculates the average floc size as a function of time. Because of its simplicity, the W98 model is ideal for implementing into larger sediment transport models; however, the model tends to over predict the dependency of the floc size on concentration. It was found that the modification of the coefficients within the original model did not allow for the model to capture the dependency on concentration. Therefore, a new term within the breakup kernel of the W98 formulation was added. The new formulation results is a single size, shear limited, and time dependent flocculation model that is able to effectively capture the dependency of the equilibrium size of flocs on both suspended sediment concentration and the time to equilibrium. The overall behavior of the new model is explored and showed align well with other studies on flocculation. Winterwerp, J. C. (1998). A simple model for turbulence induced flocculation of cohesive sediment. .Journal of Hydraulic Research, 36(3):309-326.

Numerical Simulation of Radial and Angular Distribution of γ-Ray's Energy Deposition in Scintillation Optical Fibre

International Nuclear Information System (INIS)

Tang Shibiao; Yin Zejie; Tang Yu; Huang Huan

2006-01-01

Angular and radial distributions of the energy deposition of γ-ray radiation in scintillation optical fibres are simulated and analysed using the Geant4 system. The results show a linear relation between the energy deposition and the radius of the fibres. The deposition is roughly inversely proportional to sinθ with θ the incident angle relative to the fibre axis. The results could provide corrections to the measurements of the scintillation fibres used in monitoring the γ-ray radiation

Morphology and structural studies of WO_3 films deposited on SrTiO_3 by pulsed laser deposition

International Nuclear Information System (INIS)

Kalhori, Hossein; Porter, Stephen B.; Esmaeily, Amir Sajjad; Coey, Michael; Ranjbar, Mehdi; Salamati, Hadi

2016-01-01

Highlights: • Highly oriented WO_3 stoichiometric films were determined using pulsed laser deposition method. • Effective parameters on thin films including temperature, oxygen partial pressure and laser energy fluency was studied. • A phase transition was observed in WO_3 films at 700 °C from monoclinic to tetragonal. - Abstract: WO_3 films have been grown by pulsed laser deposition on SrTiO_3 (001) substrates. The effects of substrate temperature, oxygen partial pressure and energy fluence of the laser beam on the physical properties of the films were studied. Reflection high-energy electron diffraction (RHEED) patterns during and after growth were used to determine the surface structure and morphology. The chemical composition and crystalline phases were obtained by XPS and XRD respectively. AFM results showed that the roughness and skewness of the films depend on the substrate temperature during deposition. Optimal conditions were determined for the growth of the highly oriented films.

All-optical time-resolved measurement of laser energy modulation in a relativistic electron beam

Directory of Open Access Journals (Sweden)

D. Xiang

2011-11-01

Full Text Available We propose and demonstrate an all-optical method to measure laser energy modulation in a relativistic electron beam. In this scheme the time-dependent energy modulation generated from the electron-laser interaction in an undulator is converted into time-dependent density modulation with a chicane, which is measured to infer the laser energy modulation. The method, in principle, is capable of simultaneously providing information on femtosecond time scale and 10^{-5} energy scale not accessible with conventional methods. We anticipate that this method may have wide applications in many laser-based advanced beam manipulation techniques.

First-principles X-ray absorption dose calculation for time-dependent mass and optical density.

Science.gov (United States)

Berejnov, Viatcheslav; Rubinstein, Boris; Melo, Lis G A; Hitchcock, Adam P

2018-05-01

A dose integral of time-dependent X-ray absorption under conditions of variable photon energy and changing sample mass is derived from first principles starting with the Beer-Lambert (BL) absorption model. For a given photon energy the BL dose integral D(e, t) reduces to the product of an effective time integral T(t) and a dose rate R(e). Two approximations of the time-dependent optical density, i.e. exponential A(t) = c + aexp(-bt) for first-order kinetics and hyperbolic A(t) = c + a/(b + t) for second-order kinetics, were considered for BL dose evaluation. For both models three methods of evaluating the effective time integral are considered: analytical integration, approximation by a function, and calculation of the asymptotic behaviour at large times. Data for poly(methyl methacrylate) and perfluorosulfonic acid polymers measured by scanning transmission soft X-ray microscopy were used to test the BL dose calculation. It was found that a previous method to calculate time-dependent dose underestimates the dose in mass loss situations, depending on the applied exposure time. All these methods here show that the BL dose is proportional to the exposure time D(e, t) ≃ K(e)t.

Development of Real-Time Measurement of Effective Dose for High Dose Rate Neutron Fields

CERN Document Server

Braby, L A; Reece, W D

2003-01-01

Studies of the effects of low doses of ionizing radiation require sources of radiation which are well characterized in terms of the dose and the quality of the radiation. One of the best measures of the quality of neutron irradiation is the dose mean lineal energy. At very low dose rates this can be determined by measuring individual energy deposition events, and calculating the dose mean of the event size. However, at the dose rates that are normally required for biology experiments, the individual events can not be separated by radiation detectors. However, the total energy deposited in a specified time interval can be measured. This total energy has a random variation which depends on the size of the individual events, so the dose mean lineal energy can be calculated from the variance of repeated measurements of the energy deposited in a fixed time. We have developed a specialized charge integration circuit for the measurement of the charge produced in a small ion chamber in typical neutron irradiation exp...

A proton-recoil neutron spectrometer for time-dependent ion temperatures on the National Ignition Facility

International Nuclear Information System (INIS)

Murphy, T.J.

1995-01-01

Ion temperatures from inertial confinement fusion targets are usually determined by measuring the Doppler broadening of the neutron spectrum using the time-of-flight method. Measurement systems are generally designed so that the contribution of the duration of neutron production (∼100 ps) to the width of the neutron signal is negligible. This precludes the possibility of time-dependent ion temperature. If, however, one could measure the neutron energy and arrival time at a detector independently, then time-dependent neutron spectra could be obtained, and ion temperature information deduced. A concept utilizing a proton-recoil neutron spectrometer has been developed in which recoil protons from a small plastic foil are measured. From the energy, arrival time, and recoil angle of the recoil proton, the birth time and energy of the incident neutron can be deduced. The sensitivity of the system is low, but the higher anticipated neutron yields from the proposed National Ignition Facility may make the technique feasible. Large scintillator arrays currently in use on the Nova facility for neutron spectral measurements consist of ∼1,000 channels and detect between 50 and 500 counts for typical time-integrated data. Time-dependent results would then require about an order of magnitude larger system. Key issues for making this system feasible will be keeping the cost per channel low while allowing adequately time (∼ 50 ps), energy (20 keV), and angular resolution (2 mrad) for each of the proton detectors

Monte Carlo study of radial energy deposition from primary and secondary particles for narrow and large proton beamlet source models

International Nuclear Information System (INIS)

Peeler, Christopher R; Titt, Uwe

2012-01-01

In spot-scanning intensity-modulated proton therapy, numerous unmodulated proton beam spots are delivered over a target volume to produce a prescribed dose distribution. To accurately model field size-dependent output factors for beam spots, the energy deposition at positions radial to the central axis of the beam must be characterized. In this study, we determined the difference in the central axis dose for spot-scanned fields that results from secondary particle doses by investigating energy deposition radial to the proton beam central axis resulting from primary protons and secondary particles for mathematical point source and distributed source models. The largest difference in the central axis dose from secondary particles resulting from the use of a mathematical point source and a distributed source model was approximately 0.43%. Thus, we conclude that the central axis dose for a spot-scanned field is effectively independent of the source model used to calculate the secondary particle dose. (paper)

pH Dependent Studies of Chemical Bath Deposition Grown ZnO-SiO{sub 2} Core-Shell Thin Films

Energy Technology Data Exchange (ETDEWEB)

Seth, Rajni; Panwar, Sanjay [Maharishi Markandeshwar University, Ambala (India); Kumar, Sunil; Kang, T. W.; Jeon, H. C. [Dongguk University, Seoul (Korea, Republic of)

2017-01-15

ZnO-SiO{sub 2} core-shell thin films were synthesized using chemical-bath deposition at different pH. Optical studies were done to optimize the thin films to find suitable parameters for solar cell buffer layers. These studies were done by measuring the transmission at 500 nm, which is the peak of the solar spectrum. All the parameters were seen to be highly pH dependent. The transmittance for a sample synthesized with a pH of 10.8 reached 85%. The transmittance was found not to depend on the bandgap values, but it was found possibly to depend on the fewer defect states created at a particular pH, as shown by Urbach energy and scanning electron microscopy (SEM) surface structure. An appreciable transmittance was observed in the blue region of the spectrum which had been missing until now in commercial CdS-based buffer layers. The Fourier-transform infrared and the energy dispersive X-ray spectra confirmed that the films were composed of only ZnO and silica only : no impurities were found. The urbach energy values and the SEM image of sample S3 clearly indicate the creation of fewer of defects, leading to higher crystallintiy and higher transmittance. Therefore, this shortcoming can be resolved by the substituted buffer layer of ZnO:SiO{sub 2} nano-composite thin film, which can enhance the blue response of the photovoltaic cells.

Energy dependence of nonlocal optical potentials

Science.gov (United States)

Lovell, A. E.; Bacq, P.-L.; Capel, P.; Nunes, F. M.; Titus, L. J.

2017-11-01

Recently, a variety of studies have shown the importance of including nonlocality in the description of reactions. The goal of this work is to revisit the phenomenological approach to determining nonlocal optical potentials from elastic scattering. We perform a χ2 analysis of neutron elastic scattering data off 40Ca, 90Zr, and 208Pb at energies E ≈5 -40 MeV, assuming a Perey and Buck [Nucl. Phys. 32, 353 (1962), 10.1016/0029-5582(62)90345-0] or Tian et al. [Int. J. Mod. Phys. E 24, 1550006 (2015), 10.1142/S0218301315500068] nonlocal form for the optical potential. We introduce energy and asymmetry dependencies in the imaginary part of the potential and refit the data to obtain a global parametrization. Independently of the starting point in the minimization procedure, an energy dependence in the imaginary depth is required for a good description of the data across the included energy range. We present two parametrizations, both of which represent an improvement over the original potentials for the fitted nuclei as well as for other nuclei not included in our fit. Our results show that, even when including the standard Gaussian nonlocality in optical potentials, a significant energy dependence is required to describe elastic-scattering data.

Management of solar energy in microgrids using IoT-based dependable control

OpenAIRE

Phung, Manh Duong; De La Villefromoy, Michel; Ha, Quang

2017-01-01

Solar energy generation requires efficient monitoring and management in moving towards technologies for net-zero energy buildings. This paper presents a dependable control system based on the Internet of Things (IoT) to control and manage the energy flow of renewable energy collected by solar panels within a microgrid. Data for optimal control include not only measurements from local sensors but also meteorological information retrieved in real-time from online sources. For system fault toler...

A time dependent zonally averaged energy balance model to be incorporated into IMAGE (Integrated Model to Assess the Greenhouse Effect). Collaborative Paper

International Nuclear Information System (INIS)

Jonas, M.; Olendrzynski, K.; Elzen, M. den

1991-10-01

The Intergovernmental Panel on Climate Change (IPCC) is placing increasing emphasis on the use of time-dependent impact models that are linked with energy-emission accounting frameworks and models that predict in a time-dependent fashion important variables such as atmospheric concentrations of greenhouse gases, surface temperature and precipitation. Integrating these tools (greenhouse gas emission strategies, atmospheric processes, ecological impacts) into what is called an integrated assessment model will assist policymakers in the IPCC and elsewhere to assess the impacts of a wide variety of emission strategies. The Integrated Model to Assess the Greenhouse Effect (IMAGE; developed at RIVM) represents such an integrated assessment model which already calculates historical and future effects of greenhouse gas emissions on global surface temperature, sea level rise and other ecological and socioeconomic impacts. However, to be linked to environmental impact models such as the Global Vegetation Model and the Timber Assessment Model, both of which are under development at RIVM and IIASA, IMAGE needs to be regionalized in terms of temperature and precipitation output. These key parameters will then enable the above environmental impact models to be run in a time-dependent mode. In this paper we lay the scientific and numerical basis for a two-dimensional Energy Balance Model (EBM) to be integrated into the climate module of IMAGE which will ultimately provide scenarios of surface temperature and precipitation, resolved with respect to latitude and height. This paper will deal specifically with temperature; following papers will deal with precipitation. So far, the relatively simple EBM set up in this paper resolves mean annual surface temperatures on a regional scale defined by 10 deg latitude bands. In addition, we can concentrate on the implementation of the EBM into IMAGE, i.e., on the steering mechanism itself. Both reasons justify the time and effort put into

Ellipsometric study of nanostructured carbon films deposited by pulsed laser deposition

International Nuclear Information System (INIS)

Bereznai, M.; Budai, J.; Hanyecz, I.; Kopniczky, J.; Veres, M.; Koos, M.; Toth, Z.

2011-01-01

When depositing carbon films by plasma processes the resulting structure and bonding nature strongly depends on the plasma energy and background gas pressure. To produce different energy plasma, glassy carbon targets were ablated by laser pulses of different excimer lasers: KrF (248 nm) and ArF (193 nm). To modify plume characteristics argon atmosphere was applied. The laser plume was directed onto Si substrates, where the films were grown. To evaluate ellipsometric measurements first a combination of the Tauc-Lorentz oscillator and the Sellmeier formula (TL/S) was applied. Effective Medium Approximation models were also used to investigate film properties. Applying argon pressures above 10 Pa the deposits became nanostructured as indicated by high resolution scanning electron microscopy. Above ∼ 100 and ∼ 20 Pa films could not be deposited by KrF and ArF laser, respectively. Our ellipsometric investigations showed, that with increasing pressure the maximal refractive index of both series decreased, while the optical band gap starts with a decrease, but shows a non monotonous course. Correlation between the size of the nanostructures, bonding structure, which was followed by Raman spectroscopy and optical properties were also investigated.

Effects of Time-Dependent Inflow Perturbations on Turbulent Flow in a Street Canyon

Science.gov (United States)

Duan, G.; Ngan, K.

2017-12-01

Urban flow and turbulence are driven by atmospheric flows with larger horizontal scales. Since building-resolving computational fluid dynamics models typically employ steady Dirichlet boundary conditions or forcing, the accuracy of numerical simulations may be limited by the neglect of perturbations. We investigate the sensitivity of flow within a unit-aspect-ratio street canyon to time-dependent perturbations near the inflow boundary. Using large-eddy simulation, time-periodic perturbations to the streamwise velocity component are incorporated via the nudging technique. Spatial averages of pointwise differences between unperturbed and perturbed velocity fields (i.e., the error kinetic energy) show a clear dependence on the perturbation period, though spatial structures are largely insensitive to the time-dependent forcing. The response of the error kinetic energy is maximized for perturbation periods comparable to the time scale of the mean canyon circulation. Frequency spectra indicate that this behaviour arises from a resonance between the inflow forcing and the mean motion around closed streamlines. The robustness of the results is confirmed using perturbations derived from measurements of roof-level wind speed.

Energy deposition evaluation for ultra-low energy electron beam irradiation systems using calibrated thin radiochromic film and Monte Carlo simulations

Energy Technology Data Exchange (ETDEWEB)

Matsui, S., E-mail: smatsui@gpi.ac.jp; Mori, Y. [The Graduate School for the Creation of New Photonics Industries, 1955-1 Kurematsucho, Nishiku, Hamamatsu, Shizuoka 431-1202 (Japan); Nonaka, T.; Hattori, T.; Kasamatsu, Y.; Haraguchi, D.; Watanabe, Y.; Uchiyama, K.; Ishikawa, M. [Hamamatsu Photonics K.K. Electron Tube Division, 314-5 Shimokanzo, Iwata, Shizuoka 438-0193 (Japan)

2016-05-15

For evaluation of on-site dosimetry and process design in industrial use of ultra-low energy electron beam (ULEB) processes, we evaluate the energy deposition using a thin radiochromic film and a Monte Carlo simulation. The response of film dosimeter was calibrated using a high energy electron beam with an acceleration voltage of 2 MV and alanine dosimeters with uncertainty of 11% at coverage factor 2. Using this response function, the results of absorbed dose measurements for ULEB were evaluated from 10 kGy to 100 kGy as a relative dose. The deviation between the responses of deposit energy on the films and Monte Carlo simulations was within 15%. As far as this limitation, relative dose estimation using thin film dosimeters with response function obtained by high energy electron irradiation and simulation results is effective for ULEB irradiation processes management.

Time-dependent angular distribution of sputtered particles from amorphous targets

International Nuclear Information System (INIS)

Yamamura, Yasunori

1990-01-01

Using the time-evolution computer simulation code DYACAT, the time-dependent behavior of sputtering phenomena has been investigated. The DYACAT program is based on the binary collision approximation, and the cascade development in solids is followed time-evolutionally. The total sputtering yield, the angular distribution and the energy distribution of sputtered atoms are calculated as a function of time for 1 keV Ar→Cu, where the angle of incidence is the inverse surface normal. It is found that the angular distribution of the prompt collisional phase of the sputtering process shows an under-cosine and that the corresponding energy spectrum has a peak near 10 eV. The slow collisional phase of 1 keV Ar→Cu will start after 3x10 -14 s, and its angular distribution shows an over-cosine distribution. (orig.)

Comparing of the Reaction Time in Substance-Dependent and Non-Dependent Individuals

Directory of Open Access Journals (Sweden)

Mohammad Narimani

2012-11-01

Full Text Available Aim: The aim of this study was to compare the simple, selective, and discrimination reaction time in substance-dependent and non-dependent individuals. Method: In this causal-comparative study, the population included of 425 males (opium and crystal dependents who were referred to addiction rehabilitation centers in Tabriz. By random sampling, 16 opium dependents, 16 crystal dependents, and 16 non-dependent individuals with no history of dependency as the compare group were selected. All groups peered in age, and marital status. For gathering data, “Addicts Admit Questionnaire” and laboratory device known as the "Reaction Time Assay" have been used. Results: The results of this study showed that there are significant differences among all groups in simple reaction time, choice reaction time and reaction time to auditory stimuli, but no significant difference in discrimination reaction time and reaction time to visual stimulus observed. Conclusion: The reaction time of substance-dependent groups is slower than non-dependent groups.

The penetration, diffusion and energy deposition of high-energy photon in layered media

International Nuclear Information System (INIS)

Zhengming, Luo; Chengjun, Gou; Laub, Wolfram

2002-01-01

This paper presents a new theory for calculating the transport of high-energy photons and their secondary charged particles. We call this new algorithm characteristic line method, which is completely analytic. Using this new method we can not only accurately calculate the transport behavior of energetic photons, but also precisely describes the transport behavior and energy deposition of secondary electrons, photoelectrons, Compton recoil electrons and positron-electron pairs. Its calculation efficiency is much higher than the Monte Carlo method's. The theory can be directly applied to layered media situation and obtain a pencil-beam-modeled solution. Therefore, it may be applied to clinical applications for radiation therapy

Low energy neutron scattering for energy dependent cross sections. General considerations

Energy Technology Data Exchange (ETDEWEB)

Rothenstein, W; Dagan, R [Technion-Israel Inst. of Tech., Haifa (Israel). Dept. of Mechanical Engineering

1996-12-01

We consider in this paper some aspects related to neutron scattering at low energies by nuclei which are subject to thermal agitation. The scattering is determined by a temperature dependent joint scattering kernel, or the corresponding joint probability density, which is a function of two variables, the neutron energy after scattering, and the cosine of the angle of scattering, for a specified energy and direction of motion of the neutron, before the interaction takes place. This joint probability density is easy to calculate, when the nucleus which causes the scattering of the neutron is at rest. It can be expressed by a delta function, since there is a one to one correspondence between the neutron energy change, and the cosine of the scattering angle. If the thermal motion of the target nucleus is taken into account, the calculation is rather more complicated. The delta function relation between the cosine of the angle of scattering and the neutron energy change is now averaged over the spectrum of velocities of the target nucleus, and becomes a joint kernel depending on both these variables. This function has a simple form, if the target nucleus behaves as an ideal gas, which has a scattering cross section independent of energy. An energy dependent scattering cross section complicates the treatment further. An analytic expression is no longer obtained for the ideal gas temperature dependent joint scattering kernel as a function of the neutron energy after the interaction and the cosine of the scattering angle. Instead the kernel is expressed by an inverse Fourier Transform of a complex integrand, which is averaged over the velocity spectrum of the target nucleus. (Abstract Truncated)

Nanostructure of PDMS–TEOS–PrZr hybrids prepared by direct deposition of gamma radiation energy

International Nuclear Information System (INIS)

Lancastre, Joana J.H.; Falcão, António N.; Margaça, Fernanda M.A.; Ferreira, Luís M.; Miranda Salvado, Isabel M.; Almásy, László; Casimiro, Maria H.; Meiszterics, Anikó

2015-01-01

Highlights: • Hybrid materials were prepared by direct energy deposition. • The influence of the catalyst content (PrZr) was investigated. • The developed oxide network was found to be strongly dependent on the PrZr content. • A model is proposed for the development of the oxide network in these materials. - Abstract: Organic–inorganic materials have been the object of intense research due to their wide range of properties and therefore innumerous applications. We prepared organic–inorganic hybrid materials by direct energy deposition on a mixture of polydimethylsiloxane silanol terminated (33 wt% fixed content), tetraethylorthosilicate and a minor content of zirconium propoxide that varied from 1 to 5 wt% using gamma radiation from a Co-60 source. The samples, dried in air at room temperature, are bulk, flexible and transparent. Their nanostructure was investigated by small angle neutron scattering. It was found that the inorganic oxide network has fractal structure, which becomes denser as the zirconium propoxide content decreases. The results suggest that oxide nanosized regions grow from the OH terminal group of PDMS which are the condensation seeds. Their number and position remains unaltered with the variation of zirconium propoxide content that only affects their microstructure. A model is proposed for the nanostructure of the oxide network that develops in the irradiation processed hybrid materials.

Nanostructure of PDMS–TEOS–PrZr hybrids prepared by direct deposition of gamma radiation energy

Energy Technology Data Exchange (ETDEWEB)

Lancastre, Joana J.H., E-mail: jlancastre@ctn.ist.utl.pt [C2TN, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 (km 139.7), 2695-066 Bobadela, LRS (Portugal); Falcão, António N. [C2TN, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 (km 139.7), 2695-066 Bobadela, LRS (Portugal); Margaça, Fernanda M.A., E-mail: fmargaca@ctn.ist.utl.pt [C2TN, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 (km 139.7), 2695-066 Bobadela, LRS (Portugal); Ferreira, Luís M. [C2TN, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 (km 139.7), 2695-066 Bobadela, LRS (Portugal); Miranda Salvado, Isabel M. [CICECO & Departamento de Engenharia de Materiais e Cerâmica, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Almásy, László [Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, PO Box 49, 1525 Budapest (Hungary); Casimiro, Maria H. [REQUIMTE/CQFB, Departamento de Química, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Meiszterics, Anikó [Gedeon Richter Ltd., PO Box 27, H-1475 Budapest (Hungary)

2015-10-15

Highlights: • Hybrid materials were prepared by direct energy deposition. • The influence of the catalyst content (PrZr) was investigated. • The developed oxide network was found to be strongly dependent on the PrZr content. • A model is proposed for the development of the oxide network in these materials. - Abstract: Organic–inorganic materials have been the object of intense research due to their wide range of properties and therefore innumerous applications. We prepared organic–inorganic hybrid materials by direct energy deposition on a mixture of polydimethylsiloxane silanol terminated (33 wt% fixed content), tetraethylorthosilicate and a minor content of zirconium propoxide that varied from 1 to 5 wt% using gamma radiation from a Co-60 source. The samples, dried in air at room temperature, are bulk, flexible and transparent. Their nanostructure was investigated by small angle neutron scattering. It was found that the inorganic oxide network has fractal structure, which becomes denser as the zirconium propoxide content decreases. The results suggest that oxide nanosized regions grow from the OH terminal group of PDMS which are the condensation seeds. Their number and position remains unaltered with the variation of zirconium propoxide content that only affects their microstructure. A model is proposed for the nanostructure of the oxide network that develops in the irradiation processed hybrid materials.

Normalization of energy-dependent gamma survey data.

Science.gov (United States)

Whicker, Randy; Chambers, Douglas

2015-05-01

Instruments and methods for normalization of energy-dependent gamma radiation survey data to a less energy-dependent basis of measurement are evaluated based on relevant field data collected at 15 different sites across the western United States along with a site in Mongolia. Normalization performance is assessed relative to measurements with a high-pressure ionization chamber (HPIC) due to its "flat" energy response and accurate measurement of the true exposure rate from both cosmic and terrestrial radiation. While analytically ideal for normalization applications, cost and practicality disadvantages have increased demand for alternatives to the HPIC. Regression analysis on paired measurements between energy-dependent sodium iodide (NaI) scintillation detectors (5-cm by 5-cm crystal dimensions) and the HPIC revealed highly consistent relationships among sites not previously impacted by radiological contamination (natural sites). A resulting generalized data normalization factor based on the average sensitivity of NaI detectors to naturally occurring terrestrial radiation (0.56 nGy hHPIC per nGy hNaI), combined with the calculated site-specific estimate of cosmic radiation, produced reasonably accurate predictions of HPIC readings at natural sites. Normalization against two to potential alternative instruments (a tissue-equivalent plastic scintillator and energy-compensated NaI detector) did not perform better than the sensitivity adjustment approach at natural sites. Each approach produced unreliable estimates of HPIC readings at radiologically impacted sites, though normalization against the plastic scintillator or energy-compensated NaI detector can address incompatibilities between different energy-dependent instruments with respect to estimation of soil radionuclide levels. The appropriate data normalization method depends on the nature of the site, expected duration of the project, survey objectives, and considerations of cost and practicality.

Towards a climate-dependent paradigm of ammonia emission and deposition

Science.gov (United States)

Sutton, Mark A.; Reis, Stefan; Riddick, Stuart N.; Dragosits, Ulrike; Nemitz, Eiko; Theobald, Mark R.; Tang, Y. Sim; Braban, Christine F.; Vieno, Massimo; Dore, Anthony J.; Mitchell, Robert F.; Wanless, Sarah; Daunt, Francis; Fowler, David; Blackall, Trevor D.; Milford, Celia; Flechard, Chris R.; Loubet, Benjamin; Massad, Raia; Cellier, Pierre; Personne, Erwan; Coheur, Pierre F.; Clarisse, Lieven; Van Damme, Martin; Ngadi, Yasmine; Clerbaux, Cathy; Skjøth, Carsten Ambelas; Geels, Camilla; Hertel, Ole; Wichink Kruit, Roy J.; Pinder, Robert W.; Bash, Jesse O.; Walker, John T.; Simpson, David; Horváth, László; Misselbrook, Tom H.; Bleeker, Albert; Dentener, Frank; de Vries, Wim

2013-01-01

Existing descriptions of bi-directional ammonia (NH3) land–atmosphere exchange incorporate temperature and moisture controls, and are beginning to be used in regional chemical transport models. However, such models have typically applied simpler emission factors to upscale the main NH3 emission terms. While this approach has successfully simulated the main spatial patterns on local to global scales, it fails to address the environment- and climate-dependence of emissions. To handle these issues, we outline the basis for a new modelling paradigm where both NH3 emissions and deposition are calculated online according to diurnal, seasonal and spatial differences in meteorology. We show how measurements reveal a strong, but complex pattern of climatic dependence, which is increasingly being characterized using ground-based NH3 monitoring and satellite observations, while advances in process-based modelling are illustrated for agricultural and natural sources, including a global application for seabird colonies. A future architecture for NH3 emission–deposition modelling is proposed that integrates the spatio-temporal interactions, and provides the necessary foundation to assess the consequences of climate change. Based on available measurements, a first empirical estimate suggests that 5°C warming would increase emissions by 42 per cent (28–67%). Together with increased anthropogenic activity, global NH3 emissions may increase from 65 (45–85) Tg N in 2008 to reach 132 (89–179) Tg by 2100. PMID:23713128

Advanced Materials Enabled by Atomic Layer Deposition for High Energy Density Rechargeable Batteries

Science.gov (United States)

Chen, Lin

In order to meet the ever increasing energy needs of society and realize the US Department of Energy (DOE)'s target for energy storage, acquiring a fundamental understanding of the chemical mechanisms in batteries for direct guidance and searching novel advanced materials with high energy density are critical. To realize rechargeable batteries with superior energy density, great cathodes and excellent anodes are required. LiMn2O4 (LMO) has been considered as a simpler surrogate for high energy cathode materials like NMC. Previous studies demonstrated that Al2O3 coatings prepared by atomic layer deposition (ALD) improved the capacity of LMO cathodes. This improvement was attributed to a reduction in surface area and diminished Mn dissolution. However, here we propose a different mechanism for ALD Al 2O3 on LMO based on in-situ and ex-situ investigations coupled with density functional theory calculations. We discovered that Al2O 3 not only coats the LMO, but also dopes the LMO surface with Al leading to changes in the Mn oxidation state. Different thicknesses of Al2O 3 were deposited on nonstoichiometric LiMn2O4 for electrochemical measurements. The LMO treated with one cycle of ALD Al2O3 (1xAl 2O3 LMO) to produce a sub-monolayer coating yielded a remarkable initial capacity, 16.4% higher than its uncoated LMO counterpart in full cells. The stability of 1xAl2O3 LMO is also much better as a result of stabilized defects with Al species. Furthermore, 4xAl 2O3 LMO demonstrates remarkable capacity retention. Stoichiometric LiMn2O4 was also evaluated with similar improved performance achieved. All superior results, accomplished by great stability and reduced Mn dissolution, is thanks to the synergetic effects of Al-doping and ALD Al2O 3 coating. Turning our attention to the anode, we again utilized aluminum oxide ALD to form conformal films on lithium. We elaborately designed and studied, for the first time, the growth mechanism during Al2O3 ALD on lithium metal in

Inter-comparison of MARS and FLUKA: Predictions on Energy Deposition in LHC IR Quadrupoles

CERN Document Server

Hoa, C; Cerutti, F; Ferrai, A

2008-01-01

Detailed modellings of the LHC insertion regions (IR) have earlier been performed to evaluate energy deposition in the IR superconducting magnets [1-4]. Proton-proton collisions at 14 TeV in the centre of mass lead to debris, depositing energy in the IR components. To evaluate uncertainties in those simulations and gain further confidence in the tools and approaches used, inter-comparison calculations have been performed with the latest versions of the FLUKA (2006.3b) [5, 6] and MARS15 [7, 8] Monte Carlo codes. These two codes, used worldwide for multi particle interaction and transport in accelerator, detector and shielding components, have been thoroughly benchmarked by the code authors and the user community (see, for example, recent [9, 10]). In the study described below, a better than 5% agreement was obtained for energy deposition calculated with these two codes - based on different independent physics models - for the identical geometry and initial conditions of a simple model representing the IR5 and ...

Inter-comparison of MARS and FLUKA: Predictions on energy deposition in LHC IR quadrupoles

International Nuclear Information System (INIS)

Hoa, Christine; Cerutti, F.; Ferrari, A.; Mokhov, N.V.

2008-01-01

Detailed modelings of the LHC insertion regions (IR) have earlier been performed to evaluate energy deposition in the IR superconducting magnets [1-4]. Proton-proton collisions at 14 TeV in the centre of mass lead to debris, depositing energy in the IR components. To evaluate uncertainties in those simulations and gain further confidence in the tools and approaches used, inter-comparison calculations have been performed with the latest versions of the FLUKA (2006.3b) [5, 6] and MARS15 [7, 8] Monte Carlo codes. These two codes, used worldwide for multi particle interaction and transport in accelerator, detector and shielding components, have been thoroughly benchmarked by the code authors and the user community (see, for example, recent [9, 10]). In the study described below, a better than 5% agreement was obtained for energy deposition calculated with these two codes--based on different independent physics models--for the identical geometry and initial conditions of a simple model representing the IR5 and its first quadrupole

Nuclear symmetry energy in density dependent hadronic models

International Nuclear Information System (INIS)

Haddad, S.

2008-12-01

The density dependence of the symmetry energy and the correlation between parameters of the symmetry energy and the neutron skin thickness in the nucleus 208 Pb are investigated in relativistic Hadronic models. The dependency of the symmetry energy on density is linear around saturation density. Correlation exists between the neutron skin thickness in the nucleus 208 Pb and the value of the nuclear symmetry energy at saturation density, but not with the slope of the symmetry energy at saturation density. (author)

Time-dependent simulations of disk-embedded planetary atmospheres

Science.gov (United States)

Stökl, A.; Dorfi, E. A.

2014-03-01

At the early stages of evolution of planetary systems, young Earth-like planets still embedded in the protoplanetary disk accumulate disk gas gravitationally into planetary atmospheres. The established way to study such atmospheres are hydrostatic models, even though in many cases the assumption of stationarity is unlikely to be fulfilled. Furthermore, such models rely on the specification of a planetary luminosity, attributed to a continuous, highly uncertain accretion of planetesimals onto the surface of the solid core. We present for the first time time-dependent, dynamic simulations of the accretion of nebula gas into an atmosphere around a proto-planet and the evolution of such embedded atmospheres while integrating the thermal energy budget of the solid core. The spherical symmetric models computed with the TAPIR-Code (short for The adaptive, implicit RHD-Code) range from the surface of the rocky core up to the Hill radius where the surrounding protoplanetary disk provides the boundary conditions. The TAPIR-Code includes the hydrodynamics equations, gray radiative transport and convective energy transport. The results indicate that diskembedded planetary atmospheres evolve along comparatively simple outlines and in particular settle, dependent on the mass of the solid core, at characteristic surface temperatures and planetary luminosities, quite independent on numerical parameters and initial conditions. For sufficiently massive cores, this evolution ultimately also leads to runaway accretion and the formation of a gas planet.

Electron energy deposition in a multilayered carbon--uranium--carbon configuration and in semi-infinite uranium

International Nuclear Information System (INIS)

Lockwood, G.J.; Miller, G.H.; Halbleib, J.A. Sr.

1977-10-01

Absolute measurements of electron energy deposition profiles are reported here for electrons incident on the multilayer configuration of carbon-uranium-carbon. These measurements were for normally incident source electrons at an energy of 1.0 MeV. To complement these measurements, electron energy deposition profiles were also obtained for electrons incident on semi-infinite uranium as a function of energy and angle of incidence. The results are compared with the predictions of a coupled electron/photon Monte Carlo transport model. In general, the agreement between theory and experiment is good. This work was in support of the Reactor Safety Research Equation-of-State Program

Density and starting-energy dependent effective interaction

International Nuclear Information System (INIS)

Yamaguchi, Norio; Nagata, Sinobu; Kasuga, Teruo

1979-01-01

A new effective potential constructed from the reaction matrix calculation of nuclear matters is proposed, taking three-body effects into account. Starting from the two-body scattering equation for nuclear matters, an equation with averaged momentum is introduced as the definition of effective interaction. The parameters in the equation are the Fermi momentum and the starting energy. The nuclear density dependence and the starting energy dependence are independently treated in the potential. The effective interactions including three-body effects were calculated. The dependence on the starting energy is large. The effective interaction is more attractive in the triplet E state, and assures overall saturation without any artificial renormalization. The reaction matrix calculation can be well reproduced by the calculation with this effective potential. The results of calculation for the binding energy of He-4 and O-16 and the shell model matrix elements of O-16 are represented. (Kato, T.)

Origin of non-quantum noise and time dependent thermo field dynamics

International Nuclear Information System (INIS)

Umezawa, H.

1991-01-01

Common features and physically profound differences are summarized between various kinds of noise in pure states caused by the Bogoliubov transformation in such diverse phenomena as the squeezed state in quantum optics, Hawking radiation around the eternal black hole, and thermal physics.All the thermal vacua form a set of states degenerate in eigenvalues of the Hamiltonian H-circumflex, i.e., the zero-hat energy states. The presence of these degenerate energy states exhibits the spontaneous breakdown of weak Bogoliubov symmetry. The thermal freedom is the freedom of moving through the states in this degenerate set. Considering a time-dependent movement of a thermal vacuum through the degenerate set, the time-dependent thermal field dynamics are obtained. With this formalism the authors set up a quasi-particle picture and analyze the spectral representation of the Heisenberg two point Green's function and the diagonalization of the quasi-particle Hamiltonian. The formalism will be used in discussion of the appearance of short time intermediate high-temperature states when the initial state is at practically zero temperature. (author). 28 refs

Spectroscopic and DFT studies of calix[4]arene: time-dependent DFT calculations for elucidating the variation in the excitation energies with geometry

Energy Technology Data Exchange (ETDEWEB)

Boo, Bong Hyun; Kwak, Hae Ran; Hong, Seung Ki [Chungnam National University, Daejeon (Korea, Republic of); Park, Chan Jo [Korea Research Institute of Chemical Technology, Daejeon (Korea, Republic of); No, Kwang Hyun [Sookmyung Womens University, Seoul (Korea, Republic of)

2010-08-15

We have searched low-lying conformers of calix[4]arene and found one global minimum having a cone shape, together with three conformers such as partial cone-shape conformers. We then elucidated the thermodynamics for the conformational changes by performing density-functional theory (DFT) calculations. The time-dependent DFT calculation enabled us to assign the absorption spectrum and to reveal a variation of the excitation energies with geometry.

Thickness dependent growth of low temperature atomic layer deposited zinc oxide films

International Nuclear Information System (INIS)

Montiel-González, Z.; Castelo-González, O.A.; Aguilar-Gama, M.T.; Ramírez-Morales, E.; Hu, H.

2017-01-01

Highlights: • Polycrystalline columnar ZnO thin films deposited by ALD at low temperatures. • Higher deposition temperature leads to a greater surface roughness in the ALD ZnO films. • Higher temperature originates larger refractive index values of the ALD ZnO films. • ZnO thin films were denser as the numbers of ALD deposition cycles were larger. • XPS analysis revels mayor extent of the DEZ reaction during the ALD process. - Abstract: Zinc oxide films are promising to improve the performance of electronic devices, including those based on organic materials. However, the dependence of the ZnO properties on the preparation conditions represents a challenge to obtain homogeneous thin films that satisfy specific applications. Here, we prepared ZnO films of a wide range of thicknesses by atomic layer deposition (ALD) at relatively low temperatures, 150 and 175 °C. From the results of X-ray photoelectron spectroscopy, X-ray diffraction and Spectroscopic Ellipsometry it is concluded that the polycrystalline structure of the wurtzite is the main phase of the ALD samples, with OH groups on their surface. Ellipsometry revealed that the temperature and the deposition cycles have a strong effect on the films roughness. Scanning electron micrographs evidenced such effect, through the large pyramids developed at the surface of the films. It is concluded that crystalline ZnO thin films within a broad range of thickness and roughness can be obtained for optic or optoelectronic applications.

Nonlinear time-dependent simulation of helix traveling wave tubes

International Nuclear Information System (INIS)

Peng Wei-Feng; Yang Zhong-Hai; Hu Yu-Lu; Li Jian-Qing; Lu Qi-Ru; Li Bin

2011-01-01

A one-dimensional nonlinear time-dependent theory for helix traveling wave tubes is studied. A generalized electromagnetic field is applied to the expression of the radio frequency field. To simulate the variations of the high frequency structure, such as the pitch taper and the effect of harmonics, the spatial average over a wavelength is substituted by a time average over a wave period in the equation of the radio frequency field. Under this assumption, the space charge field of the electron beam can be treated by a space charge wave model along with the space charge coefficient. The effects of the radio frequency and the space charge fields on the electrons are presented by the equations of the electron energy and the electron phase. The time-dependent simulation is compared with the frequency-domain simulation for a helix TWT, which validates the availability of this theory. (interdisciplinary physics and related areas of science and technology)

Progress Report on Alloy 617 Time Dependent Allowables

Energy Technology Data Exchange (ETDEWEB)

Wright, Julie Knibloe [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-06-01

Time dependent allowable stresses are required in the ASME Boiler and Pressure Vessel Code for design of components in the temperature range where time dependent deformation (i.e., creep) is expected to become significant. There are time dependent allowable stresses in Section IID of the Code for use in the non-nuclear construction codes, however, there are additional criteria that must be considered in developing time dependent allowables for nuclear components. These criteria are specified in Section III NH. St is defined as the lesser of three quantities: 100% of the average stress required to obtain a total (elastic, plastic, primary and secondary creep) strain of 1%; 67% of the minimum stress to cause rupture; and 80% of the minimum stress to cause the initiation of tertiary creep. The values are reported for a range of temperatures and for time increments up to 100,000 hours. These values are determined from uniaxial creep tests, which involve the elevated temperature application of a constant load which is relatively small, resulting in deformation over a long time period prior to rupture. The stress which is the minimum resulting from these criteria is the time dependent allowable stress St. In this report data from a large number of creep and creep-rupture tests on Alloy 617 are analyzed using the ASME Section III NH criteria. Data which are used in the analysis are from the ongoing DOE sponsored high temperature materials program, form Korea Atomic Energy Institute through the Generation IV VHTR Materials Program and historical data from previous HTR research and vendor data generated in developing the alloy. It is found that the tertiary creep criterion determines St at highest temperatures, while the stress to cause 1% total strain controls at low temperatures. The ASME Section III Working Group on Allowable Stress Criteria has recommended that the uncertainties associated with determining the onset of tertiary creep and the lack of significant

Dual-energy CT (DECT) imaging of tophi and monosodium urate deposits in a patient with longstanding anorexia nervosa

DEFF Research Database (Denmark)

Weihe, Johan Petur; Birger Morillon, Melanie; Lambrechtsen, Jess

Dual-energy CT (DECT) imaging of tophi and monosodium urate deposits in a patient with longstanding anorexia nervosa......Dual-energy CT (DECT) imaging of tophi and monosodium urate deposits in a patient with longstanding anorexia nervosa...

Microdroplet deposition through a film-free laser forward printing technique

Energy Technology Data Exchange (ETDEWEB)

Patrascioiu, A.; Fernandez-Pradas, J.M.; Morenza, J.L. [Departament de Fisica Aplicada i Optica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Serra, P., E-mail: pserra@ub.edu [Departament de Fisica Aplicada i Optica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain)

2012-09-15

Highlights: Black-Right-Pointing-Pointer Circular droplets are obtained for a wide range of focusing depths at fixed energy. Black-Right-Pointing-Pointer Focusing depth variation study reveals two abrupt transitions in droplet diameter. Black-Right-Pointing-Pointer Liquid ejection mechanism is mediated by two types of jets of different origin. Black-Right-Pointing-Pointer Evolution of jets depends on the focusing depth accounting for the seen transitions. - Abstract: A recently developed film-free laser forward microprinting technique allows printing transparent and weakly absorbing liquids with high resolution and reproducibility. Its operating principle consists in the tight focusing of ultrashort laser pulses inside the liquid, and near its free surface, such that all the laser energy is absorbed in a small region around the beam waist. A cavitation bubble is then created inside the liquid, whose subsequent expansion results into the ejection of liquid. The collection of the ejected liquid on a substrate leads to the deposition of micron-sized droplets. In this work, we investigate a relevant process parameter of the technique, namely the laser focusing depth, and its influence on the morphology of the deposited droplets. The study reveals that for a fixed laser pulse energy there exists a relatively wide range of focusing depths at which circular and uniform droplets can be printed. The process of liquid ejection is also investigated. Time-resolved images reveal that liquid ejection proceeds through the formation of two kinds of jets which display clearly differentiated dynamics, and which could provide an interpretation for the dependence observed between the morphology of the deposited droplets and the laser focusing depth.

Exact Time-Dependent Wave Functions of a Confined Time-Dependent Harmonic Oscillator with Two Moving Boundaries

International Nuclear Information System (INIS)

Lo, C.F.

2009-01-01

By applying the standard analytical techniques of solving partial differential equations, we have obtained the exact solution in terms of the Fourier sine series to the time-dependent Schroedinger equation describing a quantum one-dimensional harmonic oscillator of time-dependent frequency confined in an infinite square well with the two walls moving along some parametric trajectories. Based upon the orthonormal basis of quasi-stationary wave functions, the exact propagator of the system has also been analytically derived. Special cases like (i) a confined free particle, (ii) a confined time-independent harmonic oscillator, and (iii) an aging oscillator are examined, and the corresponding time-dependent wave functions are explicitly determined. Besides, the approach has been extended to solve the case of a confined generalized time-dependent harmonic oscillator for some parametric moving boundaries as well. (general)

Charge and energy dependence of the residence time of cosmic ray nuclei below 15 GeV/nucleon

International Nuclear Information System (INIS)

Soutoul, A.; Engelmann, J.J.; Ferrando, P.; Koch-Miramond, L.; Masse, P.; Webber, W.R.

1985-01-01

The relative abundance of nuclear species measured in cosmic rays at Earth has often been interpreted with the simple leaky box model. For this model to be consistent an essential requirement is that the escape length does not depend on the nuclear species. The discrepancy between escape length values derived from iron secondaries and from the B/C ratio was identified by Garcia-Munoz and his co-workers using a large amount of experimental data. Ormes and Protheroe found a similar trend in the HEAO data although they questioned its significance against uncertainties. They also showed that the change in the B/C ratio values implies a decrease of the residence time of cosmic rays at low energies in conflict with the diffusive convective picture. These conclusions crucially depend on the partial cross section values and their uncertainties. Recently new accurate cross sections of key importance for propagation calculations have been measured. Their statistical uncertainties are often better than 4% and their values significantly different from those previously accepted. Here, these new cross sections are used to compare the observed B/C+O and (Sc to Cr)/Fe ratio to those predicted with the simple leaky box model

Calorific energy deposited by gamma radiations in a test reactor. Calorimetric measurements and calculations

International Nuclear Information System (INIS)

Mecheri, K.-F.

1977-01-01

The purpose of this work was to determine the calorific energy deposited by gamma radiations in the experimental devices irradiated in the test reactors of the Grenoble Nuclear Study Centre. A theoretical study briefly recalls to mind the various sorts of nuclear reactions that occur in a reactor, from the special angle of their ability to deposit calorific energy in the materials. A special study with the help of a graphite calorimeter made it possible to show the possible effect of the various parameters intervening in this energy absorption: the nature of the materials, their geometry, the spectrum of the incident gamma rays and the fact that the variation of this spectrum is due to the position of the measuring point with respect to the reactor core or to the presence of structures around the measuring instrument. The results of the calculations made with the help of the Mercury IV and ANISN codes are compared with those of the determinations in order to ascertain that very are adapted to the forecasts of energy deposition in the various materials. The conclusion was reached that in order to calculate with accuracy the depositifs of gamma energy in the experimental devices, it is necessary either to introduce the build-up calculation for the low energy photons, in the Mercury IV calculation code or to associate the DOT code to the ANISN calculation code [fr

Study of energy dependence of a extrapolation chamber in low energy X-rays beams

International Nuclear Information System (INIS)

Bastos, Fernanda M.; Silva, Teogenes A. da

2014-01-01

This work was with the main objective to study the energy dependence of extrapolation chamber in low energy X-rays to determine the value of the uncertainty associated with the variation of the incident radiation energy in the measures in which it is used. For studying the dependence of energy, were conducted comparative ionization current measurements between the extrapolation chamber and two ionization chambers: a chamber mammography, RC6M model, Radcal with energy dependence less than 5% and a 2575 model radioprotection chamber NE Technology; both chambers have very thin windows, allowing its application in low power beams. Measurements were made at four different depths of 1.0 to 4.0 mm extrapolation chamber, 1.0 mm interval, for each reference radiation. The study showed that there is a variable energy dependence on the volume of the extrapolation chamber. In other analysis, it is concluded that the energy dependence of extrapolation chamber becomes smaller when using the slope of the ionization current versus depth for the different radiation reference; this shows that the extrapolation technique, used for the absorbed dose calculation, reduces the uncertainty associated with the influence of the response variation with energy radiation

Dependability of wind energy generators with short-term energy storage.

Science.gov (United States)

Sørensen, B

1976-11-26

Power fluctuations and power duration curves for wind energy generators, including energy storage facilities of a certain capacity, are compared to those of typical nuclear reactors. A storage system capable of delivering the yearly average power output for about 10 hours already makes the dependability of the wind energy system comparable to that of a typical nuclear plant.

Industry-relevant magnetron sputtering and cathodic arc ultra-high vacuum deposition system for in situ x-ray diffraction studies of thin film growth using high energy synchrotron radiation.

Science.gov (United States)

Schroeder, J L; Thomson, W; Howard, B; Schell, N; Näslund, L-Å; Rogström, L; Johansson-Jõesaar, M P; Ghafoor, N; Odén, M; Nothnagel, E; Shepard, A; Greer, J; Birch, J

2015-09-01

We present an industry-relevant, large-scale, ultra-high vacuum (UHV) magnetron sputtering and cathodic arc deposition system purposefully designed for time-resolved in situ thin film deposition/annealing studies using high-energy (>50 keV), high photon flux (>10(12) ph/s) synchrotron radiation. The high photon flux, combined with a fast-acquisition-time (film formation processes. The high-energy synchrotron-radiation based x-rays result in small scattering angles (industry-relevant processes. We openly encourage the materials research community to contact us for collaborative opportunities using this unique and versatile scientific instrument.

Italy's recurrent energy dependency dilemma

International Nuclear Information System (INIS)

Ippolito, F.

1993-01-01

This paper first critically assesses the objectives of Italy's 1988 National Energy Plan which, in light of the moratorium on nuclear energy, called for moderate but steady reductions in imported energy supplies through the implementation of energy conservation programs and the development of available domestic conventional and renewable energy sources. The economics and energy analyses evidence that, in view this nation's current troubled economic situation, the Energy Plan's target for the year 2000 of a 76% dependency on foreign oil is just not good enough and not in line with stricter European environmental normatives limiting carbon dioxide emissions. It is argued that in order to effectively reduce the nation's excessively high energy costs, keep pace with other industrialized countries in a highly competitive market (Italy's energy tariffs are almost 55% greater than those of Germany and France), and to respect new European anti-pollution laws, Italy must restart its nuclear program and take advantage of the recent advances being made in passive reactor safety systems

Energy-dependent point interactions in one dimension

International Nuclear Information System (INIS)

Coutinho, F A B; Nogami, Y; Tomio, Lauro; Toyama, F M

2005-01-01

We consider a new type of point interaction in one-dimensional quantum mechanics. It is characterized by a boundary condition at the origin that involves the second and/or higher order derivatives of the wavefunction. The interaction is effectively energy dependent. It leads to a unitary S-matrix for the transmission-reflection problem. The energy dependence of the interaction can be chosen such that any given unitary S-matrix (or the transmission and reflection coefficients) can be reproduced at all energies. Generalization of the results to coupled-channel cases is discussed

Time-Dependent Behaviors of Granite: Loading-Rate Dependence, Creep, and Relaxation

Science.gov (United States)

Hashiba, K.; Fukui, K.

2016-07-01

To assess the long-term stability of underground structures, it is important to understand the time-dependent behaviors of rocks, such as their loading-rate dependence, creep, and relaxation. However, there have been fewer studies on crystalline rocks than on tuff, mudstone, and rock salt, because the high strength of crystalline rocks makes the detection of their time-dependent behaviors much more difficult. Moreover, studies on the relaxation, temporal change of stress and strain (TCSS) conditions, and relations between various time-dependent behaviors are scarce for not only granites, but also other rocks. In this study, previous reports on the time-dependent behaviors of granites were reviewed and various laboratory tests were conducted using Toki granite. These tests included an alternating-loading-rate test, creep test, relaxation test, and TCSS test. The results showed that the degree of time dependence of Toki granite is similar to other granites, and that the TCSS resembles the stress-relaxation curve and creep-strain curve. A viscoelastic constitutive model, proposed in a previous study, was modified to investigate the relations between the time-dependent behaviors in the pre- and post-peak regions. The modified model reproduced the stress-strain curve, creep, relaxation, and the results of the TCSS test. Based on a comparison of the results of the laboratory tests and numerical simulations, close relations between the time-dependent behaviors were revealed quantitatively.

Time-dependent potential-functional embedding theory

International Nuclear Information System (INIS)

Huang, Chen; Libisch, Florian; Peng, Qing; Carter, Emily A.

2014-01-01

We introduce a time-dependent potential-functional embedding theory (TD-PFET), in which atoms are grouped into subsystems. In TD-PFET, subsystems can be propagated by different suitable time-dependent quantum mechanical methods and their interactions can be treated in a seamless, first-principles manner. TD-PFET is formulated based on the time-dependent quantum mechanics variational principle. The action of the total quantum system is written as a functional of the time-dependent embedding potential, i.e., a potential-functional formulation. By exploiting the Runge-Gross theorem, we prove the uniqueness of the time-dependent embedding potential under the constraint that all subsystems share a common embedding potential. We derive the integral equation that such an embedding potential needs to satisfy. As proof-of-principle, we demonstrate TD-PFET for a Na 4 cluster, in which each Na atom is treated as one subsystem and propagated by time-dependent Kohn-Sham density functional theory (TDDFT) using the adiabatic local density approximation (ALDA). Our results agree well with a direct TDDFT calculation on the whole Na 4 cluster using ALDA. We envision that TD-PFET will ultimately be useful for studying ultrafast quantum dynamics in condensed matter, where key regions are solved by highly accurate time-dependent quantum mechanics methods, and unimportant regions are solved by faster, less accurate methods

Competing risks and time-dependent covariates

DEFF Research Database (Denmark)

Cortese, Giuliana; Andersen, Per K

2010-01-01

Time-dependent covariates are frequently encountered in regression analysis for event history data and competing risks. They are often essential predictors, which cannot be substituted by time-fixed covariates. This study briefly recalls the different types of time-dependent covariates......, as classified by Kalbfleisch and Prentice [The Statistical Analysis of Failure Time Data, Wiley, New York, 2002] with the intent of clarifying their role and emphasizing the limitations in standard survival models and in the competing risks setting. If random (internal) time-dependent covariates...

Dependence of the quasipotential on the total energy of a two-particle system

International Nuclear Information System (INIS)

Kapshai, V.N.; Savrin, V.I.; Skachkov, N.B.

1987-01-01

For a system of two relativistic particles described in the Logunov-Tavkhelidze one-time approach the dependence of the quasipotential of one-boson exchange on the total energy of the system is calculated. It is shown that despite the nonlocal form of the obtained quasipotential the three-dimensional equations for the waves function can be reduced by a partial expansion to one-dimensional equations. The influence of the energy dependence of the quasipotential on its behavior in the coordinate representation is discussed

Morphology and structural studies of WO{sub 3} films deposited on SrTiO{sub 3} by pulsed laser deposition

Energy Technology Data Exchange (ETDEWEB)

Kalhori, Hossein, E-mail: h.kalhori@ph.iut.ac.ir [School of Physics and CRANN, Trinity College, Dublin 2 (Ireland); Department of Physics, Isfahan University of Technology, Isfahan 84156-8311 (Iran, Islamic Republic of); Porter, Stephen B.; Esmaeily, Amir Sajjad; Coey, Michael [School of Physics and CRANN, Trinity College, Dublin 2 (Ireland); Ranjbar, Mehdi; Salamati, Hadi [Department of Physics, Isfahan University of Technology, Isfahan 84156-8311 (Iran, Islamic Republic of)

2016-12-30

Highlights: • Highly oriented WO{sub 3} stoichiometric films were determined using pulsed laser deposition method. • Effective parameters on thin films including temperature, oxygen partial pressure and laser energy fluency was studied. • A phase transition was observed in WO{sub 3} films at 700 °C from monoclinic to tetragonal. - Abstract: WO{sub 3} films have been grown by pulsed laser deposition on SrTiO{sub 3} (001) substrates. The effects of substrate temperature, oxygen partial pressure and energy fluence of the laser beam on the physical properties of the films were studied. Reflection high-energy electron diffraction (RHEED) patterns during and after growth were used to determine the surface structure and morphology. The chemical composition and crystalline phases were obtained by XPS and XRD respectively. AFM results showed that the roughness and skewness of the films depend on the substrate temperature during deposition. Optimal conditions were determined for the growth of the highly oriented films.

Deformation of Ag clusters deposited on Au(111) - Experiment and molecular dynamics

Energy Technology Data Exchange (ETDEWEB)

Miroslawski, Natalie; Groenhagen, Niklas; Hoevel, Heinz [TU Dortmund, Experimentelle Physik I (Germany); Issendorff, Bernd von [Universitaet Freiburg, Fakultaet Physik (Germany); Jaervi, Tommi [Fraunhofer Institut fuer Werkstoffmechanik, Freiburg (Germany); Moseler, Michael [Universitaet Freiburg, Fakultaet Physik (Germany); Fraunhofer Institut fuer Werkstoffmechanik, Freiburg (Germany); Freiburger Materialforschungszentrum (Germany)

2011-07-01

Mass selected clusters from Ag{sup +}{sub 55} to Ag{sup +}{sub 147{+-}}{sub 2} were deposited with different deposition energies at 77 K on Au(111) and imaged with STM at 77 K. We observed a deformation of the cluster shape due to the strong metallic interaction between the cluster and the substrate. The clusters became epitaxial and developed a structure composed of several Ag monolayers. The number of these monolayers depends on the number of atoms in the cluster and the deposition energy. The larger the cluster mass the more monolayers the cluster develops on Au(111) and the larger the deposition energy the fewer monolayers occur. These results were verified by molecular dynamic simulations. Additionally the behaviour of Ag{sub N} clusters on Au(111) after different annealing steps was investigated.

Determination of alpha effectiveness in ESR dating using nuclear accelerator techniques: methods and energy dependence

International Nuclear Information System (INIS)

Lyons, R.G.

1988-01-01

An important parameter in calculating the environmental dose rate for electron spin resonance (ESR) age estimates is the relative effectiveness of alpha and gamma radiation. A small research accelerator is used as a source of alpha particles of various pre-selected energies, corresponding to those found in the environment, to determine the effectiveness of alpha radiation of different energies. Preparation of sample targets is discussed, including the use of absolute ethanol, thorough etching and deposition by centrifuge. Preliminary results show that the alpha/gamma effectiveness ratio, k, depends on the energy of the incident alpha and must therefore be expressed in terms of a reference energy. The effectiveness of an alpha particle in causing ESR damage is found to vary linearly with its range or path length, not with its energy, a fact which must be considered when calculating effective dose-rates from environmental radionuclide concentrations. Failure to do so may lead to serious systematic errors in the effective alpha contribution to environmental dose-rates and consequently in age estimates. (author)

Time-dependent gravitating solitons in five dimensional warped space-times

CERN Document Server

Giovannini, Massimo

2007-01-01

Time-dependent soliton solutions are explicitly derived in a five-dimensional theory endowed with one (warped) extra-dimension. Some of the obtained geometries, everywhere well defined and technically regular, smoothly interpolate between two five-dimensional anti-de Sitter space-times for fixed value of the conformal time coordinate. Time dependent solutions containing both topological and non-topological sectors are also obtained. Supplementary degrees of freedom can be also included and, in this case, the resulting multi-soliton solutions may describe time-dependent kink-antikink systems.

Dynamical properties of a particle in a time-dependent double-well potential

International Nuclear Information System (INIS)

Leonel, Edson D; McClintock, P V E

2004-01-01

Some chaotic properties of a classical particle interacting with a time-dependent double-square-well potential are studied. The dynamics of the system is characterized using a two-dimensional nonlinear area-preserving map. Scaling arguments are used to study the chaotic sea in the low-energy domain. It is shown that the distributions of successive reflections and of corresponding successive reflection times obey power laws with the same exponent. If one or both wells move randomly, the particle experiences the phenomenon of Fermi acceleration in the sense that it has unlimited energy growth

Nanocomposite oxide thin films grown by pulsed energy beam deposition

International Nuclear Information System (INIS)

Nistor, M.; Petitmangin, A.; Hebert, C.; Seiler, W.

2011-01-01

Highly non-stoichiometric indium tin oxide (ITO) thin films were grown by pulsed energy beam deposition (pulsed laser deposition-PLD and pulsed electron beam deposition-PED) under low oxygen pressure. The analysis of the structure and electrical transport properties showed that ITO films with a large oxygen deficiency (more than 20%) are nanocomposite films with metallic (In, Sn) clusters embedded in a stoichiometric and crystalline oxide matrix. The presence of the metallic clusters induces specific transport properties, i.e. a metallic conductivity via percolation with a superconducting transition at low temperature (about 6 K) and the melting and freezing of the In-Sn clusters in the room temperature to 450 K range evidenced by large changes in resistivity and a hysteresis cycle. By controlling the oxygen deficiency and temperature during the growth, the transport and optical properties of the nanocomposite oxide films could be tuned from metallic-like to insulating and from transparent to absorbing films.

Time dependent solutions of the Fokker-Planck equation for fast fusion ions

International Nuclear Information System (INIS)

Gnavi, G.; Gratton, F.T.; Heyn, M.

1990-01-01

Approximate time dependent solutions for the Fokker-Planck equation for fast fusion ions from an isotropic, monoenergetic source are presented, for the problem of D - T - He 3 reactions. The equations include the effect of diffusion, which is particularly noticeable in the distribution of particles of lower energy and in the formation of a tail of particles with energy higher than that of the source. (Author)

Atmospheric Energy Deposition Modeling and Inference for Varied Meteoroid Structures

Science.gov (United States)

Wheeler, Lorien; Mathias, Donovan; Stokan, Edward; Brown, Peter

2018-01-01

Asteroids populations are highly diverse, ranging from coherent monoliths to loosely-bound rubble piles with a broad range of material and compositional properties. These different structures and properties could significantly affect how an asteroid breaks up and deposits energy in the atmosphere, and how much ground damage may occur from resulting blast waves. We have previously developed a fragment-cloud model (FCM) for assessing the atmospheric breakup and energy deposition of asteroids striking Earth. The approach represents ranges of breakup characteristics by combining progressive fragmentation with releases of variable fractions of debris and larger discrete fragments. In this work, we have extended the FCM to also represent asteroids with varied initial structures, such as rubble piles or fractured bodies. We have used the extended FCM to model the Chelyabinsk, Benesov, Kosice, and Tagish Lake meteors, and have obtained excellent matches to energy deposition profiles derived from their light curves. These matches provide validation for the FCM approach, help guide further model refinements, and enable inferences about pre-entry structure and breakup behavior. Results highlight differences in the amount of small debris vs. discrete fragments in matching the various flare characteristics of each meteor. The Chelyabinsk flares were best represented using relatively high debris fractions, while Kosice and Benesov cases were more notably driven by their discrete fragmentation characteristics, perhaps indicating more cohesive initial structures. Tagish Lake exhibited a combination of these characteristics, with lower-debris fragmentation at high altitudes followed by sudden disintegration into small debris in the lower flares. Results from all cases also suggest that lower ablation coefficients and debris spread rates may be more appropriate for the way in which debris clouds are represented in FCM, offering an avenue for future model refinement.

Surface free energy of TiC layers deposited by electrophoretic deposition (EPD)

Science.gov (United States)

Gorji, Mohammad Reza; Sanjabi, Sohrab

2018-01-01

In this study porous structure coatings of bare TiC (i.e. 20 nm, 0.7 µm and 5/45 µm) and core-shell structures of TiC/NiP synthesized through electroless plating were deposited by EPD. Room temperature surface free energy (i.e. γs) of TiC and TiC/NiP coatings were determined via measuring contact angles of distilled water and diiodemethane liquids. The effect of Ni-P shell on spreading behavior of pure copper on porous EPD structures was also investigated by high temperature wetting experiments. According to the results existence of a Ni-P layer around the TiC particles has led to roughness (i.e. at least 0.1 µm), and porosity mean length (i.e. at least 1 µm) increase. This might be related to various sizes of TiC agglomerates formed during electroless plating. It has been observed that room temperature γs changed from 44.49 to 54.12 mJ.m-2 as a consequence of particle size enlargement for TiC. The highest and lowest (67.25 and 44.49 mJ.m-2) γs were measured for TiC nanoparticles which showed 1.5 times increase in surface free energy after being plated with Ni-P. It was also observed that plating Ni-P altered non-spreading (θs > 100 o) behavior of TiC to full-spreading ((θs 0o)) which can be useful for preparation of hard coatings by infiltration sintering phenomenon. Zeta potential of EPD suspensions, morphology, phase structure and topography of as-EPD layers were investigated through Zetasizer, field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and atomic force microscopy (AFM) instruments respectively.

Energy dependence corrections to MOSFET dosimetric sensitivity

International Nuclear Information System (INIS)

Cheung, T.; Yu, P.K.N.; Butson, M.J.; Illawarra Cancer Care Centre, Crown St, Wollongong

2009-01-01

Metal Oxide Semiconductor Field Effect Transistors (MOSFET's) are dosimeters which are now frequently utilized in radiotherapy treatment applications. An improved MOSFET, clinical semiconductor dosimetry system (CSDS) which utilizes improved packaging for the MOSFET device has been studied for energy dependence of sensitivity to x-ray radiation measurement. Energy dependence from 50 kVp to 10 MV x-rays has been studied and found to vary by up to a factor of 3.2 with 75 kVp producing the highest sensitivity response. The detectors average life span in high sensitivity mode is energy related and ranges from approximately 100 Gy for 75 kVp x-rays to approximately 300 Gy at 6MV x-ray energy. The MOSFET detector has also been studied for sensitivity variations with integrated dose history. It was found to become less sensitive to radiation with age and the magnitude of this effect is dependant on radiation energy with lower energies producing a larger sensitivity reduction with integrated dose. The reduction in sensitivity is however approximated reproducibly by a slightly non linear, second order polynomial function allowing corrections to be made to reading to account for this effect to provide more accurate dose assessments both in phantom and in-vivo.

Energy dependence corrections to MOSFET dosimetric sensitivity.

Science.gov (United States)

Cheung, T; Butson, M J; Yu, P K N

2009-03-01

Metal Oxide Semiconductor Field Effect Transistors (MOSFET's) are dosimeters which are now frequently utilized in radiotherapy treatment applications. An improved MOSFET, clinical semiconductor dosimetry system (CSDS) which utilizes improved packaging for the MOSFET device has been studied for energy dependence of sensitivity to x-ray radiation measurement. Energy dependence from 50 kVp to 10 MV x-rays has been studied and found to vary by up to a factor of 3.2 with 75 kVp producing the highest sensitivity response. The detectors average life span in high sensitivity mode is energy related and ranges from approximately 100 Gy for 75 kVp x-rays to approximately 300 Gy at 6 MV x-ray energy. The MOSFET detector has also been studied for sensitivity variations with integrated dose history. It was found to become less sensitive to radiation with age and the magnitude of this effect is dependant on radiation energy with lower energies producing a larger sensitivity reduction with integrated dose. The reduction in sensitivity is however approximated reproducibly by a slightly non linear, second order polynomial function allowing corrections to be made to readings to account for this effect to provide more accurate dose assessments both in phantom and in-vivo.

Modeling Space-Time Dependent Helium Bubble Evolution in Tungsten Armor under IFE Conditions

International Nuclear Information System (INIS)

Qiyang Hu; Shahram Sharafat; Nasr Ghoniem

2006-01-01

The High Average Power Laser (HAPL) program is a coordinated effort to develop Laser Inertial Fusion Energy. The implosion of the D-T target produces a spectrum of neutrons, X-rays, and charged particles, which arrive at the first wall (FW) at different times within about 2.5 μs at a frequency of 5 to 10 Hz. Helium is one of several high-energy charged particle constituents impinging on the candidate tungsten armored low activation ferritic steel First Wall. The spread of the implanted debris and burn helium energies results in a unique space-time dependent implantation profile that spans about 10 μm in tungsten. Co-implantation of X-rays and other ions results in spatially dependent damage profiles and rapid space-time dependent temperature spikes and gradients. The rate of helium transport and helium bubble formation will vary significantly throughout the implanted region. Furthermore, helium will also be transported via the migration of helium bubbles and non-equilibrium helium-vacancy clusters. The HEROS code was developed at UCLA to model the spatial and time-dependent helium bubble nucleation, growth, coalescence, and migration under transient damage rates and transient temperature gradients. The HEROS code is based on kinetic rate theory, which includes clustering of helium and vacancies, helium mobility, helium-vacancy cluster stability, cavity nucleation and growth and other microstructural features such as interstitial loop evolution, grain boundaries, and precipitates. The HEROS code is based on space-time discretization of reaction-diffusion type equations to account for migration of mobile species between neighboring bins as single atoms, clusters, or bubbles. HAPL chamber FW implantation conditions are used to model helium bubble evolution in the implanted tungsten. Helium recycling rate predictions are compared with experimental results of helium ion implantation experiments. (author)

Genetic Algorithm-Based Optimization to Match Asteroid Energy Deposition Curves

Science.gov (United States)

Tarano, Ana; Mathias, Donovan; Wheeler, Lorien; Close, Sigrid

2018-01-01

An asteroid entering Earth's atmosphere deposits energy along its path due to thermal ablation and dissipative forces that can be measured by ground-based and spaceborne instruments. Inference of pre-entry asteroid properties and characterization of the atmospheric breakup is facilitated by using an analytic fragment-cloud model (FCM) in conjunction with a Genetic Algorithm (GA). This optimization technique is used to inversely solve for the asteroid's entry properties, such as diameter, density, strength, velocity, entry angle, and strength scaling, from simulations using FCM. The previous parameters' fitness evaluation involves minimizing error to ascertain the best match between the physics-based calculated energy deposition and the observed meteors. This steady-state GA provided sets of solutions agreeing with literature, such as the meteor from Chelyabinsk, Russia in 2013 and Tagish Lake, Canada in 2000, which were used as case studies in order to validate the optimization routine. The assisted exploration and exploitation of this multi-dimensional search space enables inference and uncertainty analysis that can inform studies of near-Earth asteroids and consequently improve risk assessment.

Time variant layer control in atmospheric pressure chemical vapor deposition based growth of graphene

KAUST Repository

Qaisi, Ramy M.; Smith, Casey; Hussain, Muhammad Mustafa

2013-01-01

Graphene is a semi-metallic, transparent, atomic crystal structure material which is promising for its high mobility, strength and transparency - potentially applicable for radio frequency (RF) circuitry and energy harvesting and storage applications. Uniform (same number of layers), continuous (not torn or discontinuous), large area (100 mm to 200 mm wafer scale), low-cost, reliable growth are the first hand challenges for its commercialization prospect. We show a time variant uniform (layer control) growth of bi- to multi-layer graphene using atmospheric chemical vapor deposition system. We use Raman spectroscopy for physical characterization supported by electrical property analysis. © 2013 IEEE.

Time variant layer control in atmospheric pressure chemical vapor deposition based growth of graphene

KAUST Repository

Qaisi, Ramy M.

2013-04-01

Graphene is a semi-metallic, transparent, atomic crystal structure material which is promising for its high mobility, strength and transparency - potentially applicable for radio frequency (RF) circuitry and energy harvesting and storage applications. Uniform (same number of layers), continuous (not torn or discontinuous), large area (100 mm to 200 mm wafer scale), low-cost, reliable growth are the first hand challenges for its commercialization prospect. We show a time variant uniform (layer control) growth of bi- to multi-layer graphene using atmospheric chemical vapor deposition system. We use Raman spectroscopy for physical characterization supported by electrical property analysis. © 2013 IEEE.

Time-Dependent Neutron and Photon Dose-Field Analysis

Energy Technology Data Exchange (ETDEWEB)

Wooten, Hasani Omar [Georgia Inst. of Technology, Atlanta, GA (United States)

2005-08-01

A unique tool is developed that allows the user to model physical representations of complicated glovebox facilities in two dimensions and determine neutral-particle flux and ambient dose-equivalent fields throughout that geometry. The Pandemonium code, originally designed to determine flux and dose-rates only, is improved to include realistic glovebox geometries, time-dependent source and detector positions, time-dependent shielding thickness calculations, time-integrated doses, a representative criticality accident scenario based on time-dependent reactor kinetics, and more rigorous photon treatment. A primary benefit of this work has been an extensive analysis and improvement of the photon model that is not limited to the application described in this thesis. The photon model has been extended in energy range to 10 MeV to include photons from fission and new photon buildup factors have been included that account for the effects of photon buildup at slant-path thicknesses as a function of angle, where the mean free path thickness has been preserved. The overall system of codes is user-friendly and it is directly applicable to facilities such as the plutonium facility at Los Alamos National Laboratory, where high-intensity neutron and photon emitters are regularly used. The codes may be used to determine a priori doses for given work scenarios in an effort to supply dose information to process models which will in turn assist decision makers on ensuring as low as reasonably achievable (ALARA) compliance. In addition, coupling the computational results of these tools with the process model visualization tools will help to increase worker safety and radiological safety awareness.

Size dependence in non-sperm ejaculate production is reflected in daily energy expenditure and resting metabolic rate.

Science.gov (United States)

Friesen, Christopher R; Powers, Donald R; Copenhaver, Paige E; Mason, Robert T

2015-05-01

The non-sperm components of an ejaculate, such as copulatory plugs, can be essential to male reproductive success. But the costs of these ejaculate components are often considered trivial. In polyandrous species, males are predicted to increase energy allocation to the production of non-sperm components, but this allocation is often condition dependent and the energetic costs of their production have never been quantified. Red-sided garter snakes (Thamnophis sirtalis parietalis) are an excellent model with which to quantify the energetic costs of non-sperm components of the ejaculate as they exhibit a dissociated reproductive pattern in which sperm production is temporally disjunct from copulatory plug production, mating and plug deposition. We estimated the daily energy expenditure and resting metabolic rate of males after courtship and mating, and used bomb calorimetry to estimate the energy content of copulatory plugs. We found that both daily energy expenditure and resting metabolic rate were significantly higher in small mating males than in courting males, and a single copulatory plug without sperm constitutes 5-18% of daily energy expenditure. To our knowledge, this is the first study to quantify the energetic expense of size-dependent ejaculate strategies in any species. © 2015. Published by The Company of Biologists Ltd.

Scanning probe microscopy investigation of gold clusters deposited on atomically flat substrates

International Nuclear Information System (INIS)

Vandamme, N; Janssens, E; Vanhoutte, F; Lievens, P; Haesendonck, C van

2003-01-01

We systematically studied the influence of the substrate on the shape, mobility, and stability of deposited gold clusters. The Au n clusters were produced in a laser vaporization source and deposited with low kinetic energy (∼0.4 eV/atom) on atomically flat substrates (graphite, mica, and gold and silver films on mica) under UHV conditions. Their size distribution is probed with time-of-flight mass spectrometry and ranges from dimers to several hundreds of atoms. Scanning probe microscopy is used to characterize the deposited clusters and the formation of islands by cluster aggregation. On all substrates, Au n islands can be clearly distinguished and the islands are flattened despite the small impact energy. The shape and size of the island configurations are strongly system dependent. Gold clusters deposited on Au(111) and Ag(111) films grown on mica do not aggregate, but deform due to strong cluster-substrate interactions. The clusters tend to grow epitaxially on these surfaces. On graphite and on mica, deposited clusters do diffuse and aggregate. On the graphite surface, large ramified islands are formed by juxtaposition of small islands and trapping of the clusters at the step edges. On the other hand, the diffusion of the clusters on mica results in a total coalescence of the Au n clusters into compact islands

Constraints on cosmological birefringence energy dependence from CMB polarization data

International Nuclear Information System (INIS)

Gubitosi, G.; Paci, F.

2013-01-01

We study the possibility of constraining the energy dependence of cosmological birefringence by using CMB polarization data. We consider four possible behaviors, characteristic of different theoretical scenarios: energy-independent birefringence motivated by Chern-Simons interactions of the electromagnetic field, linear energy dependence motivated by a 'Weyl' interaction of the electromagnetic field, quadratic energy dependence, motivated by quantum gravity modifications of low-energy electrodynamics, and inverse quadratic dependence, motivated by Faraday rotation generated by primordial magnetic fields. We constrain the parameters associated to each kind of dependence and use our results to give constraints on the models mentioned. We forecast the sensitivity that Planck data will be able to achieve in this respect

Real-time beam tracing for control of the deposition location of electron cyclotron waves

Energy Technology Data Exchange (ETDEWEB)

Reich, M., E-mail: matthias.reich@ipp.mpg.de; Bilato, R.; Mszanowski, U.; Poli, E.; Rapson, C.; Stober, J.; Volpe, F.; Zille, R.

2015-11-15

Highlights: • We successfully integrated a real-time EC beam tracing code at ASDEX Upgrade. • The calculation of EC beam deposition location is fast enough for control purposes. • The accuracy of the deposition location calculation exceeds equivalent measurements. • The implementation method is by design portable to larger fusion devices. - Abstract: Plasma control techniques that use electron cyclotron (EC) resonance heating and current drive such as control of neoclassical tearing modes require accurate control of the deposition location of EC beams. ASDEX Upgrade has successfully implemented a real-time version of the beam-tracing code TORBEAM into its real-time diagnostic system to act as a globally available module that calculates current deposition location and its sensitivity from other real-time diagnostic measurements for all its moveable EC wave launchers. Based on a highly (100×) accelerated version of TORBEAM, the software implementation as a diagnostic process uses parallelization and achieves cycle times of 15–20 ms for determining the radial deposition location of 12 beams in the plasma. This cycle time includes data input–output overhead arising from the use of available real-time signals. The system is by design portable to other machines such as ITER.

QUIPS: Time-dependent properties of quasi-invariant self-gravitating polytropes

International Nuclear Information System (INIS)

Munier, A.; Feix, M.R.

1983-01-01

Quasi-invariance, a method based on group tranformations, is used to obtain time-dependent solutions for the expansion and/or contraction of a self-gravitating sphere of perfect gas with polytopic index n. Quasi-invariance transforms the equations of hydrodynamics into ''dual equations'' exhibiting extra terms such as a friction, a mass source or sink term, and a centripetal/centrifugal force. The search for stationary solutions in this ''dual space'' leads to a new class of time-dependent solutions, the QUIP (for Quasi-invariant polytrope), which generalizes Emden's static model and introduces a characteristic frequency a related to Jean's frequency. The second order differential equation describing the solution is integrated numerically. A critical point is seen always to exist for nnot =3. Solutions corresponding in the ''dual space'' to a time-dependent generalization of Eddington's standard model (n = 3) are discussed. These solutions conserve both the total mass and the energy. A transition between closed and open structures is seen to take place at a particular frequency a/sub c/. For n = 3, no critical point arises in the ''dual space'' due to the self-similar motion of the fluid. A new time-dependent mass-radius relation and a generalized Betti-Ritter relation are obtained. Conclusions about the existence of a minimum Q-factor are presented

Ultrasound scans and dual energy CT identify tendons as preferred anatomical location of MSU crystal depositions in gouty joints.

Science.gov (United States)

Yuan, Yuan; Liu, Chang; Xiang, Xi; Yuan, Tong-Ling; Qiu, Li; Liu, Yi; Luo, Yu-Bin; Zhao, Y; Herrmann, Martin

2018-05-01

The present study was performed to localize the articular deposition of monosodium urate (MSU) crystal in joints. We compare the detection efficiencies of dual-energy CT (DECT) and ultrasound scans. Analyses by DECT and ultrasound were performed with 184 bilateral joints of the lower limbs of 54 consecutive gout patients. All joints were categorized into (1) knee, (2) ankle, (3) MTP1, and (4) MTP2, and sorted into those with and those without detectable MSU deposition. The comparison of the positive rate between DECT and ultrasound and the agreement was performed using the McNemar test and the Cohen's κ coefficient, respectively. Next, we listed the MSU crystal deposition as assessed by ultrasound between the DECT-positive and -negative joints according to their interior structure. We included tendons, synovia, cartilage, subcutaneous tissue, etc. RESULTS: Among all joints, the percentages with MSU crystal deposition detected by DECT (99/184, 53.8%) and ultrasound (106/184, 57.6%) were comparable (P = 0.530 > 0.05). For MTP1 (21/34, 61.8%; 12/34, 35.3%; P efficient, respectively. The data concordance in 46 of 50 joints (92.00%; κ = 0.769, P location of MSU crystal deposition. The tendons are the most frequent anatomical location of MSU crystal depositions. The concordance rate of knee joints and MTP2-5 joints shows good agreement between DECT and ultrasound depending on the location.

Low temperature deposition: Properties of SiO{sub 2} films from TEOS and ozone by APCVD system

Energy Technology Data Exchange (ETDEWEB)

Juarez, H; Diaz, T; Rosendo, E; Garcia, G; Mora, F; Escalante, G [Centro de Investigacion en Dispositivos Semiconductores, Universidad Autonoma de Puebla, 14 Sur and Av. San Claudio, San Manuel 72000, Puebla (Mexico); Pacio, M; GarcIa, A, E-mail: hjuarez@cs.buap.m [Ingenieria Electrica, Secciaan Electranica del Estado Salido, Centro de Investigacian y de Estudios Avanzados del I. P. N., Av. Instituto Politecnico Nacional 2508, San Pedro Zacatenco, 07360 Mexico, D. F. (Mexico)

2009-05-01

An Atmospheric Pressure Chemical Vapor Deposition (APCVD) system was implemented for SiO{sub 2} nanometric films deposition on silicon substrates. Tetraethoxysilane (TEOS) and ozone (O{sub 3}) were used and they were mixed into the APCVD system. The deposition temperatures were very low, from 125 to 250 {sup 0}C and the deposition time ranged from 1 to 15 minutes. The measured thicknesses from the deposited SiO{sub 2} films were between 5 and 300 nm. From the by Fourier-Transform Infrared (FTIR) spectra the typical absorption bands of the Si-O bond were observed and it was also observed a dependence on the vibrational modes corresponding to hydroxyl groups with the deposition temperature where the intensity of these vibrations can be related with the grade porosity grade of the films. Furthermore an analytical model has been evoked to determine the activation energy of the reactions in the surface and the gas phase in the deposit films process.

Comparison between calculation and measurement of energy deposited by 800 MeV protons

International Nuclear Information System (INIS)

Loewe, W.E.

1980-01-01

The High Energy Transport Code, HETC, was obtained from the Radiation Shielding Information Center (RSIC) at Oak Ridge National Laboratory and altered as necessary to run on a CDC 7600 using the LTSS software in use at LLNL. HETC was then used to obtain calculated estimates of energy deposited, for comparison with a series of benchmark experiments done by LLNL. These experiments used proton beams of various energies incident on well-defined composite targets in good geometry. In this report, two aspects of the comparison between calculated and experimental energy depositions from an 800 MeV proton beam are discussed. Both aspects involve the fact that workers at SAI had previously used their version of HETC to calculate this experiment and reported their comparison with the measured data. The first aspect addressed is that their calculated data and LLNL calculations do not agree, suggesting an error in the conversion process from the RSIC code. The second aspect is not independent of the first, but is of sufficient importance to merit separate emphasis. It is that the SAI calculations agree well with experiments at the detector plate located some distance from the shower plate, whereas the LLNL calculations show a clearcut discrepancy there in comparison with the experiment. A contract was let in January 1980 by LLNL with SAI in order to obtain full details on the two cited aspects of the comparison between calculated and experimental energy depositions from an 800 MeV proton beam. The ensuing discussion is based on the final report of that contracted work

Imprint reduction in rotating heavy ions beam energy deposition

Energy Technology Data Exchange (ETDEWEB)

Bret, A., E-mail: antoineclaude.bret@uclm.es [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51, Cambridge, MA 02138 (United States); ETSI Industriales, Universidad Castilla-La Mancha, 13071 Ciudad Real (Spain); Instituto de Investigaciones Energéticas y Aplicaciones Industriales, Campus Universitario de Ciudad Real, 13071 Ciudad Real (Spain); Piriz, A.R., E-mail: Roberto.Piriz@uclm.es [ETSI Industriales, Universidad Castilla-La Mancha, 13071 Ciudad Real (Spain); Instituto de Investigaciones Energéticas y Aplicaciones Industriales, Campus Universitario de Ciudad Real, 13071 Ciudad Real (Spain); Tahir, N.A., E-mail: n.tahir@gsi.de [GSI Darmstadt, Plankstrasse 1, 64291 Darmstadt (Germany)

2014-01-01

The compression of a cylindrical target by a rotating heavy ions beam is contemplated in certain inertial fusion schemes or in heavy density matter experiments. Because the beam has its proper temporal profile, the energy deposition is asymmetric and leaves an imprint which can have important consequences for the rest of the process. In this paper, the Fourier components of the deposited ion density are computed exactly in terms of the beam temporal profile and its rotation frequency Ω. We show that for any beam profile of duration T, there exist an infinite number of values of ΩT canceling exactly any given harmonic. For the particular case of a parabolic profile, we find possible to cancel exactly the first harmonic and nearly cancel every other odd harmonics. In such case, the imprint amplitude is divided by 4 without any increase of Ω.

Imprint reduction in rotating heavy ions beam energy deposition

International Nuclear Information System (INIS)

Bret, A.; Piriz, A.R.; Tahir, N.A.

2014-01-01

The compression of a cylindrical target by a rotating heavy ions beam is contemplated in certain inertial fusion schemes or in heavy density matter experiments. Because the beam has its proper temporal profile, the energy deposition is asymmetric and leaves an imprint which can have important consequences for the rest of the process. In this paper, the Fourier components of the deposited ion density are computed exactly in terms of the beam temporal profile and its rotation frequency Ω. We show that for any beam profile of duration T, there exist an infinite number of values of ΩT canceling exactly any given harmonic. For the particular case of a parabolic profile, we find possible to cancel exactly the first harmonic and nearly cancel every other odd harmonics. In such case, the imprint amplitude is divided by 4 without any increase of Ω

Energy transport

International Nuclear Information System (INIS)

Anon.

1982-01-01

The measurement of primary interaction cross sections and the incorporation of these data into Monte Carlo calculations provide detailed information about the initial spatial distribution of absorbed dose. Our theoretical energy transport studies have focused on the use of this information to predict the evolution of chemical species formed as a result of the energy deposition. This effort has led to a stochastic approach to diffusion kinetics that can account for the influence of track structure on the yield of free radicals in the radiolysis of water. Fluorescence studies with pulsed alpha particle and proton beams provided the first experimental test of our stochastic model of tract structure effects. Our experimental studies use time-resolved emission spectroscopy to investigate the mechanism of energy transport in nonpolar liquids. Studies of the concentration dependence of time-resolved emission from solutions of benzene in cyclohexane also show the importance of using low benzene concentrations to minimize the influence of benzene dimers on the emission kinetics

Applying Boundary Conditions Using a Time-Dependent Lagrangian for Modeling Laser-Plasma Interactions

Science.gov (United States)

Reyes, Jonathan; Shadwick, B. A.

2016-10-01