scholarly journals The enthalpies of mixing of ternary liquid Ag-Ca-Ge alloys

2021 ◽  
Vol 9 (1) ◽  
pp. 51-62
Author(s):  
Natalia Kotova ◽  
Michael Ivanov ◽  
Natalia Usenko
Keyword(s):  
Molar Fraction ◽  
Enthalpy Of Mixing ◽  
Integral Enthalpy ◽  
Constant Ratio ◽  
Concentration Triangle ◽  
Ternary Interaction ◽  
Absolute Value ◽  
Enthalpies Of Mixing ◽  
Isoperibolic Calorimetry ◽  
First Time

Partial and integral enthalpies of mixing of the ternary Ag–Ca–Ge melts were determined for the first time by the high-temperature isoperibolic calorimetry at 1300–1550 K. The experiments were performed for six sections with a constant ratio of two components up to the molar fraction of the third component equal to 0.3. The enthalpies of mixing in this ternary system are exothermic values which increase in absolute value from the Ag corner of the concentration triangle towards the constituent binary Ca–Ge system. The minimum value of the integral enthalpy of mixing was obtained for Ca0.6Ge0.4 composition of the Ca–Ge binary system (about –58.00 kJ mol–1). The enthalpies of mixing of the ternary Ag–Ca–Ge melts are calculated for the whole concentration triangle by the Redlich-Kister-Muggianu method, taking into account the term of specific ternary interaction defined from our experimental data. The topology of the isoenthalpies of mixing is determined.

Enthalpies of mixing in binary Cu–Eu and ternary Al–Cu–Eu liquid alloys

2020 ◽  
Vol 111 (4) ◽  
pp. 273-282
Author(s):  
Natalia Usenko ◽  
Michael Ivanov ◽  
Natalia Kotova
Keyword(s):  
Ternary System ◽  
Enthalpy Of Mixing ◽  
Integral Enthalpy ◽  
Liquid Alloys ◽  
Temperature Range ◽  
Enthalpies Of Mixing ◽  
Minimum Value ◽  
Isoperibolic Calorimetry ◽  
Wide Range ◽  
Binary Constituent

Abstract The enthalpies of mixing in liquid alloys of the binary Cu-Eu and ternary Al-Cu-Eu systems were determined over a wide range of compositions by means of isoperibolic calorimetry in the temperature range 1 300 - 1450 K. The enthalpies of mixing in the Cu-Eu system demonstrate small exothermic effects (ΔHmin = -4.1 ± 0.5 kJ · mol-1at xCu = 0.70). The measurements for the liquid ternary Al- Cu-Eu alloys were performed along five sections (xCu/ xEu = 0.70/0.30; 0.50/0.50 and 0.27/0.73 for xAl changed from 0 up to 0.30 and xAl/xEu = 0.20/0.80 and 0.47/0.53 for xCu changed from 0 up to 0.30). The enthalpies of mixing in the ternary system were found to be exothermic and increasing in absolute values from the Al corner towards the Al0.40Cu0.60-Al0.60Eu0.40section and from the constituent binary Cu-Eu system towards the same section. The minimum value of the integral enthalpy of mixing is expected in the vicinity of the Al0.6Eu0.4composition of the binary constituent Al-Eu system (about -23.00 kJ · mol-1).

Lead-free solders: Enthalpies of mixing of liquid Ag–Cu–Ni–Sn alloys

2007 ◽  
Vol 22 (11) ◽  
pp. 3218-3225 ◽  
Author(s):  
U. Saeed ◽  
H. Flandorfer ◽  
H. Ipser
Keyword(s):  
Experimental Data ◽  
Binary Data ◽  
Quaternary System ◽  
Enthalpy Of Mixing ◽  
Integral Enthalpy ◽  
Lead Free ◽  
Enthalpies Of Mixing ◽  
Polynomial Fit ◽  
Calorimetric Technique ◽  
Lead Free Solders

Partial and integral enthalpies of mixing of liquid Ag–Cu–Ni–Sn alloys were determined at 1000 °C by a drop calorimetric technique using a Calvet type microcalorimeter. They were obtained by adding Ni to the ternary Ag–Cu–Sn alloys with different composition. The data were evaluated by means of an extended Redlich–Kister–Muggianu polynomial fit for substitutional solutions. The minimum and maximum in the quaternary system were also calculated. It was found that the maximum integral enthalpy of mixing (13,310 J/mol at 41 at.% Ag) occurs in the binary Ag–Ni system while the minimum integral enthalpy of mixing (−21,390 J/mol at 61 at.% Ni) occurs in the binary Ni–Sn system. Moreover the experimental data were compared to values calculated by different extrapolation models based on binary data.

High-temperature Calorimetry of Liquid Gd–Si and Y–Si Alloys

2005 ◽  
Vol 60 (8-9) ◽  
pp. 649-654 ◽  
Author(s):  
Dmitry S. Kanibolotsky ◽  
Olena A. Bieloborodovaa ◽  
Vladyslav V. Lisnyak
Keyword(s):  
High Temperature ◽  
Mole Fraction ◽  
Thermodynamic Data ◽  
Enthalpy Of Mixing ◽  
Integral Enthalpy ◽  
Enthalpies Of Mixing

Molten Gd-Si and Y-Si alloys were examined calorimetrically at 1760 and 1770 K, respectively. The partial enthalpies of mixing of gadolinium (Δmix H̅Gd), yttrium (Δmix H̅Y) and silicon (Δmix H̅Si) were measured. The integral enthalpy of mixing (ΔmixH) was calculated by Darken’s method. The available thermodynamic data of liquid (Gd,Y)-Si alloys were compared. The partial enthalpies of mixing of Gd and Y, and appropriate integral enthalpies of mixing, were described by polynomial dependencies versus mole fraction of Gd or Y.

Who Did the Audit? Audit Quality and Disclosures of Other Audit Participants in PCAOB Filings

2014 ◽  
Vol 90 (5) ◽  
pp. 1939-1967 ◽  
Author(s):  
Carol Callaway Dee ◽  
Ayalew Lulseged ◽  
Tianming Zhang
Keyword(s):  
Audit Quality ◽  
Market Reaction ◽  
Audit Fees ◽  
Discretionary Accruals ◽  
Multivariate Model ◽  
Significant Decline ◽  
Earnings Response Coefficients ◽  
Absolute Value ◽  
Earnings Response ◽  
First Time

ABSTRACT We empirically test whether audit quality is affected when part of an SEC issuer's audit is outsourced to auditors other than the principal auditor (“participating auditors”). We find a significantly negative market reaction and a significant decline in earnings response coefficients (ERCs) for experimental issuers disclosed for the first time as having participating auditors involved in their audits. However, we find no market reaction and no decline in ERCs for a matching sample of issuers that are not disclosed as using participating auditors, nor for issuers disclosed for the second or third time as using participating auditors. We also find actual audit quality as measured by absolute value of performance-matched discretionary accruals is lower for the experimental issuers, although we find no difference in audit fees paid by the experimental and matching issuers in a multivariate model. Our findings suggest that the PCAOB's proposed rule requiring disclosure of the use of other auditors in addition to the principal auditor would provide information useful to investors in assessing audit quality for SEC issuers.

Thermodynamic properties of melts of Bi—Eu system

2021 ◽  
Vol 2021 (2) ◽  
pp. 90-100
Author(s):  
V. S. Sudavtsova ◽  
◽  
V,A, Shevchuk ◽  
L. O. Romanova ◽  
M. I. Ivanov ◽  
...  
Keyword(s):  
Enthalpy Of Mixing ◽  
Enthalpies Of Formation ◽  
Thermochemical Properties ◽  
Melting Temperatures ◽  
Large Size ◽  
Intermediate Phases ◽  
Ideal Solutions ◽  
First Time ◽  
Enthalpy Data ◽  
The Eu

The thermochemical properties of alloys were determined for the first time by calorimetry Bi—Eu system at a temperature of 1200 K in the range of 0 ≤ xBi ≤ 0,2 and 0,77 ≤ xBi ≤ 1,0. It is established that the minimum value of the enthalpy of mixing is equal to –61,7 ± 0,5 kJ / mol at xBi = 0,5. = –184,7 ± 16,7 kJ / mol, = = –206,9 ± 21,8 kJ / mol. The activities of the components were calculated according to the model of an of the ideal associated solution (IAR), using the thermochemical properties of the melts of the Bі—Eu. system. It has been established that the activities of the components show large negative deviations from ideal solutions. To predict the enthalpies of formation of LnBi compounds, the available literature data on these parameters are analyzed and the most reliable ones are presented as a dependence on ∆fH = f(ZLn). It is established that the enthalpies of formation LnBi change smoothly and monotonically with the exception of Bi—Eu and Bi—Yb systems. This is due to the large size factors for the last two systems. To combine all the enthalpy data of Ln—Bi intermetallic formation of Ln—Bi systems depending on the sequence number Ln, we need similar values for the Eu—Bi compound. But at present they are not known, so based on the above, it was assumed that the value of the minimum enthalpy of mixing will be close to the enthalpy of formation of this compound. This hypothesis is confirmed by data on the enthalpies formation of phase YbBi and equiatomic melts of binary of Yb—Bi system. To confirm the thermodynamic data, we compare the known melting temperatures of the formed intermediate phases, known from the diagrams state Bi—Ln system. The obtained dependences correlate with ∆fH = f(ZLn ) і ∆V = f(ZLn). This means that the predictions of thermochemical properties accurately reflect the nature of the considered melts of the Bi—Eu system. Keywords: thermochemical properties, melts, compounds, Bi, Eu.

Enthalpies of mixing in ternary Al–Gd–Mn liquid alloys

2021 ◽  
Vol 112 (9) ◽  
pp. 735-742
Author(s):  
Michael Ivanov ◽  
Natalia Usenko ◽  
Natalia Kotova
Keyword(s):  
Binary System ◽  
Ternary System ◽  
Liquid Alloys ◽  
Enthalpies Of Mixing ◽  
Minimum Value ◽  
Isoperibolic Calorimetry ◽  
Wide Range ◽  
Constituent Binary

Abstract The enthalpies of mixing in liquid alloys of the ternary Al–Gd–Mn system were determined over a wide range of compositions by means of isoperibolic calorimetry at 1650 K. The measurements of the partial enthalpies of components were performed along five sections: for the ΔH̅ Al (sections with x Gd/x Mn = 0.30/0.70 and 0.65/0.35 for x Al changed from 0 up to 0.30); for the ΔH̅ Gd (x Al/x Mn = 0.80/ 0.20 and 0.50/0.50 for x Gd changed from 0 up to 0.30); for the ΔH̅ Mn (x Al/x Gd = 0.29/0.71 for x Mn changed from 0 up to 0.26). The enthalpies of mixing in the ternary system were found to be exothermic and steadily increasing in absolute values from the Mn corner towards the Al–Gd constituent binary system, reaching the minimum value of approximately – 37 kJ · mol–1 in the vicinity of the Al0.6Gd0.4 composition, evidently related to the formation of stable Al2Gd phase.

Aqueous Nonelectrolyte Solutions. Part IX. Enthalpies of Mixing of Water and Deuterium Oxide with Ethylene Oxide

1971 ◽  
Vol 49 (11) ◽  
pp. 1830-1840 ◽  
Author(s):  
D. N. Glew ◽  
Harry Watts
Keyword(s):  
Hydrogen Bonding ◽  
Ethylene Oxide ◽  
Composition Range ◽  
Deuterium Oxide ◽  
Enthalpy Of Mixing ◽  
Water Systems ◽  
Oxide System ◽  
Water Proton ◽  
Oxide Systems ◽  
Enthalpies Of Mixing

Calorimetric enthalpies of mixing have been measured over the whole composition range for the water – ethylene oxide system at 10.75 and 20.00 °C and for the deuterium oxide – ethylene oxide system at 13.45 and 20.00 °C. Less extensive measurements have been made for dilute ethylene oxide solutions in water at 0.6 °C and in deuterium oxide at 4.1 and 7.3 °C. The experimental S-shaped, enthalpy of mixing – composition curves are interpreted in terms of solution hydrogen bonding changes, with particular reference to the hydrogen bonding of water. At low ethylene oxide mole fractions the deuterium oxide systems are more exothermal and at high ethylene oxide mole fractions more endothermal than the corresponding water systems. A good correlation is found between the enthalpy of mixing and the water proton magnetic resonance chemical shift for solutions with greater than 0.55 mol fraction of ethylene oxide.

Axial Impact Buckling of a Column With Random Initial Imperfections

1978 ◽  
Vol 45 (2) ◽  
pp. 361-365 ◽  
Author(s):  
I. Elishakoff
Keyword(s):  
Critical Time ◽  
Initial Imperfection ◽  
Random Variable ◽  
Axial Impact ◽  
Absolute Value ◽  
Initial Imperfections ◽  
Total Displacement ◽  
Probabilistic Setting ◽  
Probabilistic Nature ◽  
First Time

Axial impact buckling of perfectly elastic bars with initial imperfections is considered in a probabilistic setting. It is assumed that the initial imperfection function involved a single parameter, which in turn is a continuous random variable with given probability distribution function. The structure is said to buckle if the absolute value of the total displacement exceeds a prescribed value. The probabilistic nature of the random, critical time when such a failure occurs for the first time, is studied.

scholarly journals Revisiting the supersymmetric Pati–Salam models from intersecting D6-branes

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Tianjun Li ◽  
Adeel Mansha ◽  
Rui Sun
Keyword(s):  
Model Building ◽  
Gauge Coupling ◽  
Type Ii ◽  
Absolute Value ◽  
Hidden Sector ◽  
Gauge Symmetries ◽  
The Standard Model ◽  
New Models ◽  
Time Construct ◽  
First Time

AbstractEmploying novel random and supervised scanning methods, we systematically revisit the construction of three-family $$N=1$$ N = 1 supersymmetric Pati–Salam models in Type IIA orientifolds on $$\mathbf{T}^6/({\mathbb {Z}}_2\times {\mathbb {Z}}_2)$$ T 6 / ( Z 2 × Z 2 ) with intersecting D6-branes. Arising from the stacks of D6-branes with U(n) gauge symmetries, the Pati–Salam gauge symmetries $$SU(4)_C\times SU(2)_L \times SU(2)_R$$ S U ( 4 ) C × S U ( 2 ) L × S U ( 2 ) R can be broken down to the Standard Model via D-brane splitting as well as D- and F-flatness preserving Higgs mechanism. Also, the hidden sector contains USp(n) branes, which are parallel with the orientifold planes or their $${{\mathbb {Z}}_2}$$ Z 2 images. We find that the Type II T-duality in the previous study is not an equivalent relation in Pati–Salam model building if the model is not invariant under $$SU(2)_L$$ S U ( 2 ) L and $$SU(2)_R$$ S U ( 2 ) R exchange, and provides a way to obtain new models. We systematically construct the new models with three families, which usually do not have gauge coupling unification at the string scale. We for the first time construct the Pati–Salam models with at least one wrapping number whose absolute value reaching 5. In particular, for one large wrapping number equal to 5, we find that one kind of model carries more refined gauge couplings, and thus with more possibilities to have approximate gauge coupling unification.

scholarly journals Incorporation of Threshold Phenomena in Three-body Coulomb Continuum Wavefunctions

1996 ◽  
Vol 49 (6) ◽  
pp. 1095 ◽  
Author(s):  
Jamal Berakdar
Keyword(s):  
Spin Asymmetry ◽  
Excess Energy ◽  
Absolute Value ◽  
Threshold Phenomena ◽  
Cusp Conditions ◽  
Wannier Threshold ◽  
Coulomb Boundary Conditions ◽  
Three Body ◽  
Energy Sharing ◽  
First Time

In this work a three-body Coulomb wavefunction for the description of two continuum electrons moving in the field of a nucleus is constructed such that the Wannier threshold law for double escape is reproduced and the asymptotic Coulomb boundary conditions as well as the Kato cusp conditions are satisfied. It is shown that the absolute value of the total cross section, as well as the spin asymmetry, are well described by the present approach. Further, the excess-energy sharing between the two escaping electrons is calculated and analysed in light of the Wannier theory predictions. This is the first time an analytical three-body wavefunction is presented which is asymptotically exact and capable of describing threshold phenomena.

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