Efficiency Of Energy Deposition Research Articles

D-psicose is a rare sugar that provides no energy to growing rats.

D-Psicose (D-ribo-2-hexulose), a C-3 epimer of D-fructose, is present in small quantities in commercial carbohydrate complexes and agricultural products. We have previously reported that D-psicose supplements in diets suppressed hepatic lipogenic enzyme activity The lower fat accumulation in rats fed D-psicose may be due to lower lipogenesis in the liver. The present study examined the energy available in D-psicose for rat growth. Male Wistar rats received 7 g daily of a basal diet to which fixed amounts of sucrose, D-fructose, or D-psicose (0.5-2.0 g) were added for 20 d. Body weight gain and body energy gain increased with increases in sucrose and D-fructose, but not with D-psicose. One gram of sucrose, D-fructose, and D-psicose produced a net energy gain of 2.29, 1.76, and 0.007 kcal, respectively. The efficiency of energy deposition from D-psicose was 0.3% that of sucrose. The energy value of D-psicose was effectively zero. These results suggest that D-psicose is a rare sugar providing zero energy that may be useful in sweeteners for obese people as an aid for weight reduction.

Features of Fundamental- and Subharmonics ECR Heating in a Magnetic Trap

We compare the efficiency of microwave heating of electrons in a dense plasma at the fundamental harmonics (ω = eH/(mc)) and at the subharmonics (ω = eH/(2mc)) of the electron gyrofrequency. In particular, recent experimental results showing a higher efficiency of microwave heating at the frequency equal to one half of the electron gyrofrequency are analyzed. Equations describing the nonlinear subharmonic electron cyclotron resonance (ECR) heating are derived for an arbitrary geometry of the microwave field. If the microwave field has the “vacuum” polarization, then the microwave power absorbed by electrons at the fundamental harmonic of the electron gyrofrequency in rarefied plasmas exceeds by many orders of magnitude the corresponding power absorbed by electrons in the case of nonlinear heating at one half of the electron gyrofrequency. However, it is shown that this difference in a dense plasma does not exceed one order of magnitude, which is explained by the effect of depression of the resonance component of the microwave field. In this case, the efficiency of the formation of high-energy electron population can be influenced not only by the energy-deposition rate but mainly by the stability condition of an electron in the magnetic trap. It is shown that a twofold decrease in the magnetic field, necessary to satisfy the ECR condition at one half of the electron gyrofrequency, leads to a dramatic shortening of the hot-electron lifetime in a magnetic trap and, in turn, to a dramatic decrease in the energy-deposition efficiency. We discuss the dependence of the electron heating on the effect of quasi-static enhancement of the microwave field near a target located in a magnetic trap for the generation of X-ray emission.

Energy and protein utilization for maintenance and growth in Omani ram lambs in hot climates. I. Estimates of energy requirements and efficiency

Energy requirements for maintenance and growth were estimated by comparative slaughter in Omani male lambs during the hot summer months (July–October: maximum temperature, 48 °C). Weaned lambs (n = 10 per diet) were fed one of three totally mixed, 160 g CP/kg DM diets that contained 600, 400 or 200 g rhodesgrass hay/kg for low (9·98 MJ/kg, medium (10·3 MJ/kg) and high (11·4 MJ/kg) energy contents, respectively. All diets were balanced to meet the minimum nutritional needs for maximum growth. The trial lasted for 113–114 days. The purpose of having three diets was to induce a broad spectrum of growth rates that could be used in regression analysis (tested for linear, quadratic and exponential effects). Metabolizable energy (ME) intake was regressed on live weight (LW), empty body weight, tissue energy and tissue protein gain and vice versa. Coefficients of determinations were not significantly improved by quadratic or logarithmic regressions over linear relationships. Geometric mean regressions were used to control further biases due to major axis dependence when Y is regressed on X or vice versa. Based on tissue energy gain, the best estimates of ME required for maintenance (MEm) and gain (MEg) were 526 kJ/kg LW0·75/d and 42·1 kJ/kg LW0·75/g LW gain, respectively. Net energy values for maintenance (NEm) and gain (NEg) were 278 kJ/kg LW0·75/d and 20·6 kJ/kg LW0·75/g LW gain, respectively. These equations predicted MEm and NEm requirements that were similar to or slightly greater than those established by the US National Research Council (1985) and the UK Agricultural and Food Research Council (1993) for growing male lambs. The MEg and NEg requirements were substantially greater (by 43–89%) in this respect. Efficiency values were calculated as net energy available for maintenance or gain divided by the metabolizable energy available for maintenance or gain. The efficiency of metabolizable energy used for maintenance and gain was 0·50 and 0·52, respectively, and did not appear to be much different from values for other breeds of sheep in temperate climates. Dietary energy concentrations did not affect the efficiency of energy deposition. The data suggest that Omani sheep in hot climates have greater NEg requirements, and consequently MEg requirements, than other breeds of sheep in temperate climates.

Analysis of tracks induced by cluster ions inCaF2

Recent experimental data on latent tracks induced in ${\mathrm{CaF}}_{2}$ by cluster ions are analyzed applying a thermal spike model. The track evolution can be described by the same equations in radiolysis sensitive ${\mathrm{CaF}}_{2}$ and in the radiolysis resistant ${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12},$ using similar parameter values. The efficiency of the localized energy deposition $g=0.18$ for ${\mathrm{CaF}}_{2},$ which is equal within experimental error to that in ${\mathrm{Y}}_{3}{\mathrm{Fe}}_{5}{\mathrm{O}}_{12}$ at high ion velocities. This indicates that the damage cross section is not sensitive to the ion velocity in ${\mathrm{CaF}}_{2}.$ The similarities observed in the track evolution in insulating crystals, polymers, semiconductors, and high-${T}_{c}$ superconductors are explained by the Gaussian spatial distribution of the excitation energy with close values of the distribution parameters.

Enhanced energy deposition efficiency of glow discharge electron beams for metal surface treatment

The energy deposition efficiency and focal spot dynamics of electron beams produced by pulsed cold-cathode high-voltage glow discharges for metal surface treatment are investigated for two different cathode geometries. A concave cathode geometry in which the focusing is dominated by the convergence of the electric field lines in the cathode fall region is compared with flat cathode in which the focusing is exclusively caused by the self-generated magnetic field. Results of the treatment of AISI 4140 carbon steel samples show that the concave cathode geometry significantly increases the efficiency, reduces the threshold power necessary for melting, and is less sensitive to variations in the discharge parameters and sample position. The results of numerical modeling indicate that the observed increase in efficiency is caused by the longer persistence of the focal spot on the sample. The model can be used to predict the discharge parameters required for a desired treatment.

Collapsars: Gamma‐Ray Bursts and Explosions in “Failed Supernovae”

Using a two-dimensional hydrodynamics code (PROMETHEUS), we explore the continued evolution of rotating helium stars, Mα 10 M☉, in which iron-core collapse does not produce a successful outgoing shock but instead forms a black hole of 2-3 M☉. The model explored in greatest detail is the 14 M☉ helium core of a 35 M☉ main-sequence star. The outcome is sensitive to the angular momentum. For j16 ≡ j/(1016 cm2 s-1) 3, material falls into the black hole almost uninhibited. No outflows are expected. For j16 20, the infalling matter is halted by centrifugal force outside 1000 km where neutrino losses are negligible. The equatorial accretion rate is very low, and explosive oxygen burning may power a weak equatorial explosion. For 3 j16 20, however, a reasonable value for such stars, a compact disk forms at a radius at which the gravitational binding energy can be efficiently radiated as neutrinos or converted to beamed outflow by magnetohydrodynamical (MHD) processes. These are the best candidates for producing gamma-ray bursts (GRBs). Here we study the formation of such a disk, the associated flow patterns, and the accretion rate for disk viscosity parameter α ≈ 0.001 and 0.1. Infall along the rotational axis is initially uninhibited, and an evacuated channel opens during the first few seconds. Meanwhile the black hole is spun up by the accretion (to a ≈ 0.9), and energy is dissipated in the disk by MHD processes and radiated by neutrinos. For the α = 0.1 model, appreciable energetic outflows develop between polar angles of 30° and 45°. These outflows, powered by viscous dissipation in the disk, have an energy of up to a few times 1051 ergs and a mass ~1 M☉ and are rich in 56Ni. They constitute a supernova-like explosion by themselves. Meanwhile accretion through the disk is maintained for approximately 10-20 s but is time variable (±30%) because of hydrodynamical instabilities at the outer edge in a region where nuclei are experiencing photodisintegration. Because the efficiency of neutrino energy deposition is sensitive to the accretion rate, this instability leads to highly variable energy deposition in the polar regions. Some of this variability, which has significant power at 50 ms and overtones, may persist in the time structure of the burst. During the time followed, the average accretion rate for the standard α = 0.1 and j16 = 10 model is 0.07 M☉ s-1. The total energy deposited along the rotational axes by neutrino annihilation is (1-14) × 1051 ergs, depending upon the evolution of the Kerr parameter and uncertain neutrino efficiencies. Simulated deposition of energy in the polar regions, at a constant rate of 5 × 1050 ergs s-1 per pole, results in strong relativistic outflow jets beamed to about 1% of the sky. These jets may be additionally modulated by instabilities in the sides of the nozzle through which they flow. The jets blow aside the accreting material, remain highly focused, and are capable of penetrating the star in ~10 s. After the jet breaks through the surface of the star, highly relativistic flow can emerge. Because of the sensitivity of the mass ejection and jets to accretion rate, angular momentum, and disk viscosity, and the variation of observational consequences with viewing angle, a large range of outcomes is possible, ranging from bright GRBs like GRB 971214 to faint GRB-supernovae like SN 1998bw. X-ray precursors are also possible as the jet first breaks out of the star. While only a small fraction of supernovae make GRBs, we predict that collapsars will always make supernovae similar to SN 1998bw. However, hard, energetic GRBs shorter than a few seconds will be difficult to produce in this model and may require merging neutron stars and black holes for their explanation.

Surface-induced dissociation of diphenyl ether

The primary fragmentation of diphenyl ether and further secondary dissociation of its fragments have been studied by surface-induced dissociation (SID). In a tandem linear time-of-flight mass spectrometer, the dissociation of ions is studied as a function of the collision energy with a liquid perfluorinated polyether (PFPE) surface. In a tandem quadrupole instrument, an alkyl terminated (C 18) and a perfluoroalkyl terminated (FC 10) self-assembled monolayer surface have been used. The differences in the spectra obtained with the TOF and quadrupole instruments are attributed to the different time frames available for observation of the fragments. Deconvolution of the collision energy resolved SID spectra of diphenyl ether shows that above 50 eV collision energy, the energy deposition efficiency is similar in the two experimental set-ups, in spite of the different geometries. Ion/surface reactions are observed upon collisions of the diphenyl ether radical cation with the C 18 surface but not with the FC 10 surface The rearrangement fragments, obtained from perdeuterated diphenyl ether, C 11D 10 + and C 11D 9 +, react with both the C 18 and FC 10 surface. Hydrogen exchange with the surface combined with hydrocarbon loss from C 12D 10O +, C 11D 10 +, and C 11D 9 + is observed.

Amorphous track formation in SiO 2

Amorphous track formation is analyzed in SiO 2 α-quartz according to a thermal spike model. As predicted by the model, for tracks with R e > 4.5 nm R e 2 ∼ S e ( R e — the effective track radius, S e — the electronic stopping power) fulfils for α-SiO 2. The efficiency of energy deposition is g = 0.36 for low velocity ion bombardment in excellent agreement with that in yttrium iron garnet and lithium niobate. The high efficiency is the consequence of the effect of the ion velocity on the damage cross section. Tracks with R e < 4.5 nm exhibit an ambiguity that can be resolved only by new experiments. The consequences of the variation of the spatial width of the electron energy distribution with the ion velocity are discussed.

GHz ultrasonic measurement using a transient reflecting grating method under a surface plasmon resonance condition

A transient holographic pattern, which is called a transient reflecting grating (TRG), is produced on a solid surface when two pulsed lights are simultaneously irradiated at the same spot of a small size. By using a probe light delayed relative to the above excitation pulses, a time profile of the TRG is observed by changing the delay time of the probe pulse. The signal waveform includes information about generation and relaxation of ultrasonics and heat. Using this technique, a few-GHz ultrasonics were observed for a wide variation of material surfaces [A. Harata et al., Trends Anal. Chem. 14, 504–511 (1995)]. In this report highly sensitive detection of the TRGs utilizing surface plasmon resonance (SPR) is described. Energy deposition efficiency from light into heat was very effective under an SPR condition and the energy absorbed by a surface plasmon polariton (SPP) is concentrated on the solid surface. Utilizing an arrangement of total internal reflection for the SPP excitation, a TRG method about ten times more sensitive could be realized. A new type of SPR-enhanced TRG method is also proposed where the probe beam excites SPPs. The method made it possible to separate ultrasonics and the heat contribution to the TRG signal.

Separate and combined effects of ephedrine and caffeine on protein and lipid deposition in finishing pigs

AbstractTwo experiments were conducted to examine the effects of dietary inclusion of an ephedrine (Eph)/caffeine (Caf) mixture on finishing (55 to 100 kg live weight) castrated male pigs. The first experiment was conducted as a dose-response study and showed that the mixture had an optimal effect on performance and carcass composition at a dietary inclusion level of approximately 56/560 mg/kg of Eph and Caf, respectively. In the second experiment, interactions between the compounds were studied by dietary inclusion of Eph (56 mg/kg) and Caf (560 mg/kg) separately or as a mixture (56/560 mg/kg). The mixture reduced food intake by 0·12 and improved the food: gain ratio by 0·08. Muscle protein deposition rate was increased proportionately by 0·25, lipid accretion rate was decreased proportionately by 0·27, and gross energetic efficiency of energy deposition decreased proportionately by 0·09. This resulted in a changed proportional carcass composition towards more muscle (0·08) and less fat (0·21) after treatment with the mixture. The reduction in food intake was sustained due to an interaction over the first 3 weeks of treatment changing to additive effects by the compounds. The increased muscle protein deposition rate after feeding the mixture was entirely due to Eph, while the decreased gross energetic efficiency of energy deposition was caused by Caf. On the other hand, both compounds contributed almost equally to the decrease in lipid accretion rate. These results show that an Eph/Caf mixture markedly improves performance and body composition in finishing castrated pigs.

Efficiency of energy deposition in lasers pumped by uranium fission fragments

An investigation was made of the efficiency of energy deposition by fission fragments in nuclear-pumped lasers. A comparison was made with results obtained by other authors. Possible reasons for the discrepancy between the experiment and theory were analysed.

2 MeV As + implantation in InAs

High energy ion implantation of 2 MeV As + ions into 〈100〉 InAs was investigated using Rutherford backscattering spectrometry with 2 MeV He + ions. The ion fluence N 1 varied over a wide range between 2 × 10 12 cm −2 and 5 × 10 16 cm −2. The relative defect concentration n pd( z), calculated from the backscattering spectra with the help of the computer code DICADA2, is compared to the distribution of the electronic and the nuclear energy density obtained from TRIM simulations. It is found that the defect mobility and the defect annealing during room temperature implantation are strongly influenced by the total energy density deposited into electronic processes. A similar behaviour is found for GaAs but not for InP. We believe that in the arsenides the energy deposition into electronic processes reduces the efficiency of the nuclear energy deposition for producing stable defects.

'Squirrel-cage'-an effective configuration of REB injection

An effective system of REB injection has been proposed. The cylindrical N-pole magnetic wall formed by N conductors performs effective trapping of REB electrons of N band beams injected through the N cusps of multipole magnetic field. The proposed scheme of REB injection allows one to minimize beam losses and to reach a high efficiency of energy deposition into gas up to 90%. The desirable shape of beam energy deposition and plasma distribution can be realized by changing the number of magnetic poles and the value of magnetic field. The model of an effective source of argon plasma has been represented by using the Monte Carlo method in combination with a plasma kinetics simulation.

An application of minimax robust optimal control theory for selective vibrational excitation in molecules

In recent investigations control theory was applied to design electromagnetic fields capable of producing vibrational excitation in molecular systems. This approach has been applied to linear or non-linear classical approximations of molecular systems or to quantal systems using distributed cost functionals. Practical computations of molecular optimal control theory for large molecules especially with anharmonic potentials become difficult due to the increased dimensionality and the mixed nature of the boundary conditions. This paper proposes to approach the control design for such systems by treating a portion of the molecule containing the target and dipole bonds in full detail while the effect of the remainder of the system is modelled as a disturbance of limited energy. The optimal fieldminimizes the cost functional which is simultaneouslymaximized with respect to the disturbance. Such assumptions give rise to a robust controller akin to theH∞ theory of robust estimation. We investigate the various field designs for truncated harmonic systems associated with different disturbance energies and demonstrate that the existence of the solution to the associated Ricatti equation ensures the existence of the equilibrium game point. In addition, in the range of physically reasonable disturbance energy the optimal field could be accurately predicted from an asymptotic expansion involving only the undisturbed reference case. As an application we show the optimal field design for a 20 atom truncated molecular chain containing both the target bond (the 5th bond) and the dipole bonds (1st and 9th) where the disturbance only affects the end bond of the system attached to the remainder of the chain. In an effort to improve on the efficiency of the bond energy deposition we investigate shortened target times and also a 40 atom truncated chain. This approach presents very conservative estimates of possible disturbances but provides insight into the sensitivity of different configurations with respect to external disturbances. The minimax approach can be generalized to non-linear molecular systems by modelling the original system as a linear system plus an energy constrained disturbance.

Influence of the chemical composition of the hydrogen-containing component in an RH active medium and of the initiation method on the parameters of a pulsed chemical SF6–RH laser

The influence of the composition of the active medium on the lasing characteristics and energy deposition efficiency was studied under conditions of electron-beam and electric-discharge initiation in SF6–H2 and SF6–HI pulsed hydrogen fluoride chemical lasers.The best radiation energy characteristics were achieved for an SF6–HI active medium using electron-beam initiation and for an SF6–H2 active medium when the pump reaction was initiated by a self-sustained volume discharge. The following pulse parameters were obtained for an SF6–HI laser:energy 1.5 J, half-height pulse duration 60 ns,and leading edge duration 20 ns.

Numerical Investigations of Electron Beam Energy Deposition into the Gas Medium of an Excimer Laser

Electron beam propagation in a dense gas medium is numerically investigated. All the main phenomena that determine electron beam behavior in a gas (scattering and energy losses of the electrons on the gas atom molecules, ionization and excitation, electron thermalization, beam pinching, and influence of a magnetic guide field) are taken into account. The initial beam energy and the gas chamber dimensions are varied in a wide range: typical gas mixtures for the excimer lasers are considered. Graphs are given that allow the choice of the optimal electron beam energy that provides the maximum efficiency of the beam energy deposition into the gas, depending on the gas chamber dimensions.

Effect of fatty acid composition of dietary fat on energy balance and expenditure in hamsters

The comparative effects of feeding diets containing corn, olive, coconut, or menhaden fish oil on efficiency of energy deposition and on short term energy expenditure were examined in growing hamsters. Diets comprising oils mixed with laboratory diets at 10% oil w/w were fed ad libitum for 3 weeks. Animals fed laboratory diets were used as controls. Body composition was determined before and after the feeding period using 3H2O distribution space. Oxygen consumption was measured in each animal during the final week. Weight gains of groups fed corn and olive oil diets exceeded those of the group fed laboratory diet alone (p less than 0.05), although metabolizable energy intakes were similar across groups. Corn oil fed animals demonstrated higher carcass energy gains as fat compared with laboratory diet fed or menhaden oil fed groups. This was reflected in an increased fractional deposition of metabolizable energy intake in the group fed corn oil diet compared with the latter two groups. Fecal energy losses were lower in the group fed corn oil diet, and higher in the group fed laboratory diet alone, compared with other groups. Oxygen consumption did not differ between groups. These findings indicate that feeding dietary fish oil, compared with corn oil, favours energy substrate oxidation reducing the fraction of metabolizable energy partitioned for storage.

Common envelope evolution of binary stars

We discuss the common envelope phase in the evolution of binary systems. The problem of the efficiency of energy deposition into envelope ejection is treated in some detail. We describe the implications of common envelope evolution for the shaping of planetary nebulae with close binary nuclei and for double white dwarf systems, considered to be the progenitors of Type I supernovae.

Common Envelope Evolution of Binary Stars

AbstractWe discuss the common envelope phase in the evolution of binary systems. The problem of the efficiency of energy deposition into envelope ejection is treated in some detail. We describe the implications of common envelope evolution for the shaping of planetary nebulae with close binary nuclei and for double white dwarf systems, considered to be the progenitors of Type I supernovae.

The common envelope phase in the evolution of binary stars

The common envelope phase in the evolution of binary systems is examined. Three parameters are identified which characterize the efficiency of energy deposition, the importance of three-dimensional effects, and the efficiency of spin-up of the envelope. It is demonstrated that the efficiency of deposition of orbital energy into envelope ejection can be quite low. It is found that significant spin-up of the envelope can be expected to occur in relatively early stages, when the spiralling-in occurs inside evolved supergiant envelopes. In normal giants spin-up can occur only in the final stages of the spiralling-in process. The results of a simplified three-dimensional numerical calculation of the common envelope phase are presented, and the implications of the results for the formation of planetary nebulae with binary nuclei, double white dwarf systems, and FK Com stars are discussed. 52 references.