Values Of Δ2 Research Articles

Solvent pre-selection for binary mixtures based on the activity coefficient at infinite dilution in deep eutectic solvent: Tetraethylammonium chloride+ Ethylene glycol

The values of activity coefficient at infinite dilution (γ12∞) were reported for 27 solutes in tetraethylammonium chloride + ethylene glycol deep eutectic solvent (DES) system at a molar ratio of 1.000:1.997 by inverse gas chromatography (IGC) method at intervals of 10 K from 303.15 to 333.15 K. Then the measured γ12∞ values were used to determine the thermodynamic functions (ΔH1E,∞, ΔS1E,∞, and ΔG1E,∞). The values of selectivity (Sij∞) and capacity (kj∞) for six extraction problems (that is, heptane/toluene, benzene/methanol, heptane/thiophene, acetone/ethanol, cyclohexane/benzene, and cyclohexane/ethanol.) were calculated from experimental γ12∞ values and compared with literature values of other solvents under the same separation conditions. The results indicate that the studied DES is a potential extractant for separation of cyclohexane/ethanol and heptane/thiophene systems. The Flory-Huggins interaction parameters (χ12∞) were used to evaluate the miscibility between DES and organic probes, and the results reveal that alcohols exhibited the best solubility in tested DES. Furthermore, the Hildebrand solubility parameters (δ2) were calculated for tested DES, and the values of δ2 decreased with the increase of temperature.

The effect of intrinsic decoherence on quantum dynamics of two coupled double quantum dot systems

Double quantum dot (DQD) system is an ideal candidate for qubit in quantum information theory. Hence, we will investigate the two couple DQDs in the presence of intrinsic decoherence. We derive the energy spectrum and the corresponding eigenstates. Using the concurrence as a measure of entanglement for a bipartite pure state, the entanglement of the energy eigenstates is obtained and shows that the energy eigenstates reduce to the Bell states for Δ1=Δ2=0. The effects of the physical parameters such as tunneling rate between two QDs, Coulomb coupling, and intrinsic decoherence on the entanglement and the dynamics of DQD system will be examined. Furthermore, fidelity is used to measure how close the dynamically evolved state is to the initial state. It is found that for a given Γ and the smaller (larger) values of Δ2 (coulomb potential), the DQD system is more robust to the destructive effect of the intrinsic decoherence.

Phase function effects on the retrieval of oceanic high-spectral-resolution lidar.

A semianalytic Monte Carlo model is developed to simulate oceanic high-spectral-resolution lidar (HSRL) signals with multiple scattering. The phase function effects on oceanic HSRL retrieval are studied, e.g., the effective particulate 180° volume scattering function (VSF) and lidar attenuation coefficient that describe characteristics of backscatter and attenuation, respectively. The results demonstrate that the particulate backward and forward phase functions both have a significant influence on δ1, which is the relative difference between the effective and true particulate 180° VSF. The values of |δ1| are typically quite small for all phase functions at the water surface and increase with depth up to ~17% for the Fournier and Forand (FF) phase function but up to ~40% for the two-term Henyey-Greenstein (TTHG) phase function and ~75% for the one-term Henyey-Greenstein (OTHG) phase function. The reason that δ1 is not zero is due to broadening of backscattering angles from 180° caused by multiple scattering and uneven backward phase function. Also, the reason that maximum TTHG and OTHG |δ1| are larger than FF is due to less sharply increasing feature of FF in the backward direction. In addition, the particulate forward phase functions are closely related to δ2, which is the relative deviation between the lidar attenuation coefficient and the sum of the absorption and backscattering coefficients. The values of δ2 are small for all phase functions at the water surface and increase with depth up to ~12% for TTHG but up to ~26% for FF and ~31% for OTHG, due to the less peaked forward phase functions that result in more angular spread of the beam with depth and therefore result in less photons within the field of view of the lidar.

Finite Temperature Phase Diagrams of the Mixed Spin-1 and Spin-2 Blume–Capel Model by Renormalization Group Approach

The Blume–Capel model with mixed spins S = 1 and S = 2, on d-dimensional hypercubic lattice, is studied using the real space renormalization group approximation and specifically the Migdal–Kadanoff technique. We give the phase diagrams on the (Δ1/|J|, 1/|J|) and (Δ2/|J|, 1/|J|) planes which are studied for selected values of Δ2/|J| and Δ1/|J| respectively, with first and second order phase transitions and tricritical points. Also, the associated fixed points are drawn up in a table, and by linearizing the transformation at the vicinity of these points, we determine the critical exponents for d = 2 and d = 3. In particular, we find that the system under study may exhibit reentrant phenomenon.

An institutional experience of quality assurance of a treatment planning system on photon beam

AimThe purpose of the present study is to show the application of the IAEA TRS-430 QA procedures of Eclipse™v7.5 TPS for photon energies. In addition, the trends of the deviations found in the conducted tests were determined. BackgroundIn the past, the lack of complete TPS QA procedures led to some serious accidents. So, QA in the radiotherapy treatment planning process is essential for determination of accuracy in the radiotherapy process and avoidance of treatment errors. Materials and methodsThe calculations of TPS and measurements of irradiations of the treatment device were compared in the study. As a result, the local dose deviation values (δ1: central beam axis, δ2: penumbra and build up region, δ3: inside field, δ4: outside beam edges, δ50–90: beam fringe, RW50: radiological width) and their confidence limit values (including systematic and random errors) were obtained. ResultsThe confidence limit values of δ4 were detected to increase with expanding field size. The values of δ1 and δ3 of hard wedge were larger than open fields. The values of δ2 and δ50–90 of the inhomogeneity effect test were larger, especially than other tests of this study. The average deviation was showed to increase with the rise of the wedge angle. The values of δ3 and δ4 of lung irradiation were outside tolerance. ConclusionsThe QA of TPS was done and it was found that there were no reservations in its use in patient treatment. The trend of the deviations is shown.

The thermodynamics of dissolution of low-molecular-mass compounds in polymethyl[2′-(3-trifluoromethyl-2,2,3-trifluorocyclobutyl)ethyl]siloxane studied via inverse gas chromatography

The effect of the 2′-(3-trifluoromethyl-2,2,3-trifluorocyclobutyl)ethyl radical in fluorosiloxane on the thermodynamics of dissolution of various low-molecular-mass compounds in this polymer is studied via inverse gas chromatography. The activity coefficients at infinite dilution, Ω1∞, in the temperature range 20–100°C are determined for C6–C8n-alkanes, cyclohexane, benzene, toluene, tetrachloromethane, trichloromethane, 2-butanone, and ethyl acetate. Flory-Huggins interaction parameters χ12∞ are calculated. It is shown that hydrocarbons are poor solvents (Ω1∞ > 6, χ12∞ > 0.5) and that the studied fluorosiloxane is not inferior to commercial polymethyl(3,3,3-trifluoropropyl)siloxane with respect to stability in nonpolar liquid media in the range 20–70°C. Trichloromethane (above 50°C) and compounds containing a carbonyl group are found to be good solvents. The dispersion component of the solubility of the polymer, δ2, is determined to be 14.0 (J/cm3)1/2 at 20°C and slightly lower, 13.5 (J/cm3)1/2, at 100°C. Possible causes of these low values of δ2 are discussed.

Use of inverse gas chromatography to assess the compatibility of polyurethane foam with liquids at different temperatures

AbstractA crosslinked polyurethane foam has been used as the stationary phase in inverse gas chromatography to measure the solubility parameter (δ2) of the polymer at several temperatures (T) within the range 298–383 K. Values of δ2 = 29.5(MPa)1/2 at 298K and dδ2/dT = −0.06(MPa)1/2 K−1 were yielded. Linear decreases with temperature of the solubility parameters (δ1) of water, ethanol and methanol were obtained by calculation from relevant properties of the liquids. The results were used to assess the conditions for the polyurethane foam to act as a non‐interacting barrier against liquids of different polarities for which the criterion is that |δ1 − δ2| should be large. The findings highlight the need to consider both the nature of the liquid and the temperature regime.

On the ‘δ-equations’ for vortex sheet evolution

We use a set of equations, sometimes referred to as the ‘δ-equations’, to approximate the two-dimensional inviscid motion of an initially circular vortex sheet released from rest in a cross-flow. We present numerical solutions of these equations for the case with δ2 = 0 (for which the equations are exact) and for δ2 > 0. For small values of the smoothing parameter δ a spectral filter must be used to eliminate spurious instabilities due to round-off error. Two singularities appear simultaneously in the vortex sheet when δ2 = 0 at a critical time tc After tc the solutions do not converge as the computational mesh is refined. With δ2 > 0, converged solutions were found for all values of δ2 when t < tc, and for all but the two smallest values of δ2 used when t > tc. Our results show that when δ2 > 0 the vortex sheet deforms into two doubly branched spirals some time after tc The limiting solution as δ→0 clearly exists and equals the δ = 0 solution when t < tc. For t > tc, the limiting solution appears to exist if only the converged solutions are used, but it is unclear what relation this limiting solution has to any δ2 = 0 solution for these times.

The Use of Solute and Isotopic Chemistry to Identify Flow Patterns and Factors Which Limit Acid Mine Drainage in the Wasatch Range, Utah

AbstractIn this case study, we have demonstrated how a minimal amount of relatively inexpensive isotopic data can be used to help solve a complex Hydrogeologie problem.Acidic (pH 3 to 4) and neutral (pH 6.0 to 7.7) mine drain waters have been identified and sampled in the mining districts in the central Wasatch Range of Utah. The chemical evolution of acid and neutral mine waters follow fundamentally different chemical and isotopic evolutionary pathways which reflect fundamentally different flow histories. Most neutral mine discharges are either low iron calcium‐bicarbonate waters or iron and sulfate rich waters. Stable isotopic values of δ2 H and δ18 O plot near and parallel to the meteoric water line (MWL), suggesting a meteoric origin for all mine waters. 3H concentrations (20.9 to 40.8 TU) and 14C activities (46.2 to 96.3 pmc) indicate mine waters have a major component of modern recharge water. Shallow circulation of most mine discharges is suggested by low TDS, nonthermal discharge temperatures and the proximity of most mine workings to the surface.The δ34 S values of mine discharge waters tend to cluster about two nodes. Neutral mine drainages with low SO42‐ contents cluster about δ34 S = 0/o, whereas neutral mine drainages with high Sü42 contents cluster about δ34S =+5.5%o. An acid mine drainage also has a 534 S value of about 0 %o. δ34 S values of ∼ 0 %o are attributed to the oxidation ofpyrite and other sulfide minerals, whereas more positive isotopic values are attributed to isotopic fractionation accompanying the dissolution of gypsum and anhydrite. Only mine discharges with a δ34S δ 0%o have the potential to produce acid drainage. Geologic and δ13C data suggest acid mine waters (mean δ13C =−15.0%o) discharge from ground‐water flow systems generally devoid of carbonate rocks. Neutral mine waters (mean δ13C =− 9.7%o) discharge from aquifers containing abundant carbonate rocks which neutralize excess H+ ions released by the oxidization of sulfide minerals.

種々の溶媒中におけるコレステロールミリスタート, パルミタート及びオレアートの溶解度-温度関係

The phase-transition temperatures, T*, molar enthalpies, ΔH2*, and molar heat capacities, ΔCp, of pure cholesteryl esters, i. e. myristate (ChM), palmitate (ChP) and oleate (ChO), were measured by using a differential scanning calorimeter. The observed kinds of transition were crystal (k)/smectic phase (s), s/cholesteric phase (c), and c/isotropic phase (i) for ChM, k/c and c/i for ChP, and k/i transition for ChO, respectively. From the values of T*, ΔH2*, and ΔCp, the values of T* and ΔH2* of k/i transition for ChM and ChP were theoretically estimated. The molar transition enthalpies of the k/i transition, which occurs at the co-existence of solute (cholesteryl ester) and its solution with solvent, were also calculated for ChM, ChP and ChO at 298.15 K. By use of the above quantities, the solubility vs. temperature relationship of cholesteryl ester in ethanol, 1-pentanol, acetone, toluene and carbon tetrachloride was analyzed thermodynamically as well as in terms of regular solution theory. The activity coefficient of cholesteryl ester, f2, the product of solution lattice coordination number and solute-solvent interaction energy, zw, and the solubility parameter of cholesteryl ester, δ2, were estimated at 298.15K. Toluene and carbon tetrachloride were almost ideal solvents. The values of δ2 at 298.15 K were 18.0, 17.8, and 14.8 J1/2. cm-3/2 for ChM, ChP, and ChO, respectively.

Transverse-sensitivity errors in strain-gage measurement

1. Equation (5) indicates that the error in an isotropic state of stress does not depend on the properties of the material on which the gage is mounted, but it is a constant for the gage itself. (For example, ifK=+5 percent andνo=0.285, then the error will be +6.1 percent.) 2. Figure 2 indicates that the values of Δ2 become critical for values ofKb from 0.0 to −0.5 and the values of Δ1 become critical for values ofKb less than −2; i.e., for negative values ofKb we will find large percentage errors in either one of the principal stresses except ifKb lies between −0.5 and −2.0. On the other hand, the absolute values of the errors in either one of the principal stresses (i.e., |σi-σ1|) can be of great significance in that range; for example, ifQ1=−400×10−6,Q2=+200×10−6,K=5 percent, ν=0.3 andE=30×106 psi (21×1011 dynes/cm2) thenKb=−0.5 and Δ2≅-20 percent $$\begin{gathered} \therefore \dot \sigma _2 = \frac{E}{{1 - v^2 }}\left( {Q_2 + vQ_1 } \right) = + 2400{\text{ }}psi \hfill \\ \left( {154 \times 10^5 {N \mathord{\left/ {\vphantom {N {m^2 }}} \right. \kern-\nulldelimiterspace} {m^2 }}} \right) \hfill \\ \end{gathered} $$ and\(\left( {\dot \sigma _2 - \sigma _2 } \right) = - 480{\text{ }}psi\) (−30.6×105 N/m2). The true value of σ2 would then be +2880 psi (184.3×105 N/m2). In such cases, it is clearly important to take transverse-sensitivity errors into account, specially when theK factor exceeds 2 or 3 percent. For positive values ofKb the percentage errors, in general, are less. Furthermore, the true values of the stresses are then less than the calculated values, so that in such cases it would be unnecessary to make corrections for the transverse sensitivity.

Energy Straggling Parameters from Single Event Spectra

The variance of an energy straggling distribution for thin absorbers is determined by the cross section for energy loss in single collisions. The ratio, δ2, of this variance and the mean energy loss is independent of the thickness of the absorber; it is also numerically equal to the quotient of the second by the first moment of the single collision spectra. Measured doubly differential cross sections for electron emission by energetic charged particles from low-Z molecular targets provide a major part of the primary data required for calculating δ2. The relationship between δ2 and experimentally measurable cross sections for single collision energy loss is developed. Values of δ2 calculated from measured single collision cross sections are compared with values obtained from the free electron model and experiment.

Effects of Halogenated Compounds on the Rate of Radical Polymerization of Styrene

The polymerization of styrene initiated by azobisisobutyronitrile (AIBN) were carried out at 60° C in five kinds of halogenated hydrocarbon solutions. The rates of polymerization (Rp) in solutions which contained 50 vol % styrene were increased in the following order of solvent: 1, 2-dichloroethane<chlorobenzene<bromobenzene<1, 1, 2, 2-tetrachloroethane<o-dichlorobenzene. The rates of initiation of polymerization (Rt) in solvents were determine by using benzoquinone as inhibitor and then the values of δ2(=kt/kp2) werecalculated from the equation: δ2=. Rt. (M)2 /Rp2. The values of Rt hardly changed with the nature of solvents, while the values of δ2 changed markedly and showed preferably to, depend on the inverse of viscosity of the styrene-solvent system. Efficiencies of initiation of polymerization (f) in solvents were calculated from the equation, f= Rt /2 kd(AIBN), where kd is the rate of decomposition of AIBN in solvents. There was a positive correlation between the kd value and the dielectric constant of solvents, which was reported in previously. The values of f decreased with an increase of viscosity of the system. It was found that the polymerization of styrene in these solvents is still more sensitive than that is commonly supposed on the viscosity of system. t Solvent Effects in Radical Reactions. II.

Directional correlation and multipole mixing of the gamma transitions in 102Ru

Directional correlation measurements have been made on sixteen gamma cascades in 102Ru, thereby determining the spins of the levels at 944, 1581, 1837, 1873, 2037, 2219 and 2261 keV. The multipole mixtures have been deduced for the gamma transitions with energies 418.8, 627.8, 680.6, 739.2, 766.7, 1046.5, 1106.1, 1112.9, 1158.0 and 1562.0 keV. The values of δ2 for these transitions are compared with those obtained theoretically from the collective model in the hydrodynamical approximation. The predicted electron conversion coefficients are compared with the experimentally measured values and the parities of the levels are discussed.

Influence of solvent on measurement of cohesive energy density of polystyrene

The solubility parameter (δ2) of polystyrene was measured by the maximum [δ] method in four series of solvents which were structurally different. In each case δ2 varied with the solvent series used, from 8·75 to 9·25 (cal/ml)1/2 The enthalpy parameter (XH), which was calculated for polystyrene dissolved in at least one member of each series, was then used to derive δ2, and little or no variation in δ2, with solvent was observed. The average value was δ2 = 9·16 ± 0·1 (cal/ml)1/2 It has been shown that determination of δ2, from [η]max can be solvent-dependent because of the influence of the entropy term Xs. It was concluded that if reliable values of δ2 are to be obtained, they should be estimated from XH.

Hippocampus EEG in Light-Dark Discrimination Learning

The purposes of the present study were to observe the EEG of rats recorded through the lead of hippocampus and to see its quantitative change during both acquisition and extinction in light-dark discrimination learning.The quantitative analysis of the EEG for the process of both acquisition and extinction was made with a frequency analyzer. It consisted of seven band pass filters which correspond to δ2 (1-2c/s), δ1 (2-4c/s), θ (4-8c/s), α (8-13c/s), β1 (13-20c/ s), β2 (20-30c/s) and β3 (30-60c, /s). The amplitudes of momentary values of δ2, δ1, θ, α and β1 bands were measured.The followings are results.1. In the process of acquisition, the amplitudes of δ2, δ1, θ, α and β1 bands periodically changed and also amplitude of θ band decreased slowly.2. In the process of extinction, amplitudes of θ and β1 bands increased slowly, but amplitudes of δ2, δ1 and α bands increased at the same time of the beginning of extinction and after that there were little changes.