scholarly journals The Physical and Thermodynamic Functions of Borides

2017 ◽  
Vol 18 (1) ◽  
pp. 58-63
Author(s):  
N.Yu. Filonenko
Keyword(s):  
Free Energy ◽  
Physical Properties ◽  
Thermodynamic Functions ◽  
Point Of View ◽  
Energy Potential ◽  
High Temperature Expansion ◽  
Temperature Dependences ◽  
Function Calculation ◽  
First Time ◽  
Good Agreement

In the paper the physical properties and thermodynamic functions of borides Х2В (Х=W, Mo, Mn, Fe, Co, Ni та Cr) are studied with accounting for fluctuation processes. We use the microstructure analysis, the X-ray structural and the durometric analyses to determine the physical properties of alloys. In the paper it is determined the phase composition and physical properties of borides. In this paper for the first time it is determined the thermodynamic functions of borides using the Hillert and Staffansson model with accounting for the first degree approximation of high-temperature expansion for the free energy potential of binary alloys. We obtain the temperature dependences for such thermodynamic functions as Gibbs free energy, entropy, enthalpy and heat capacity Ср along with their values at the formation temperature for Х2В (Х=W, Mo, Mn, Fe, Co, Ni та Cr). The approach under consideration enables to give more thorough from the thermodynamic point of view description of borides formed from the liquid. The outcomes of the thermodynamic function calculation for borides are in good agreement with experimental data and results of other authors.

scholarly journals The peculiarities of formation and thermodynamic functions of τ-phase

2018 ◽  
Vol 26 (2) ◽  
pp. 37-44
Author(s):  
N. Yu. Filonenko ◽  
O. M. Galdina
Keyword(s):  
Boron Carbide ◽  
Carbon Content ◽  
Thermodynamic Functions ◽  
Thermodynamic Potential ◽  
Boron Content ◽  
Point Of View ◽  
No Formation ◽  
High Temperature Expansion ◽  
Temperature Dependences ◽  
First Time

It is shown that for alloys with boron content of 0.1–6.5% (wt.) and carbon content of 0.3–4.0% (wt.) without pretreatment no formation of cubic boron carbide takes place under crystallization. The cubic boron carbide can be obtained by pre-annealing at a temperature of 1173 K for an hour and further heating to a temperature of 30 K above the liquidus and cooling of alloys with boron content of 2.5–4.0% (wt.) and carbon content of 0.8–3.0% (wt.). Formation of crystals of cubic boron carbide is possible as a constituent of multiphase inclusions for alloys with boron content of 0.1–0.3% (wt.) and carbon content up to 0.4–0.5% (wt). It should be noted that for alloys with boron content of 4.2–6.0% (wt.) and  carbon content of more than 3.0% (wt.) the pretreatment does not result in formation of cubic boron carbide. The increase in boron content in the alloy to 0.3–0.5% (wt.) and carbon content to 0.5–0.7% (wt.) leads to formation of the eutectic α-Fe+Fe23(CB)6, which is arranged on the boundaries of pearlite grains. The thermodynamic functions of Fe23(CB)6 cubic boron carbide are derived for the first time using the Hillert and Staffonsson model and accounting for the first degree approximation of high-temperature expansion of the thermodynamic potential for binary alloys. We obtain temperature dependences of such thermodynamic functions for Fе23(CB)6 phase as Gibbs energy, entropy, enthalpy and heat  capacity CP , as well as calculate their values at the formation temperature of the phase. The approach used in this paper enables to give the most complete from the thermodynamic point of view description of cubic boron carbide formed from a liquid.

HIGH-TEMPERATURE SERIES FOR THERMODYNAMIC FUNCTIONS

2003 ◽  
Vol 02 (01) ◽  
pp. 1-5 ◽  
Author(s):  
FRANCISCO M. FERNÁNDEZ
Keyword(s):  
Free Energy ◽  
Perturbation Theory ◽  
High Temperature ◽  
Thermodynamic Functions ◽  
Temperature Series ◽  
Present Approach ◽  
Rigid Rotor ◽  
Temperature Expansion ◽  
High Temperature Expansion

We propose a high-temperature expansion for thermodynamic functions. As an example we calculate the free energy for a restricted plane rigid rotor and compare present approach with perturbation theory.

A thermodynamical investigation of the system benzene-diphenyl

1951 ◽  
Vol 243 (862) ◽  
pp. 169-196 ◽  
Keyword(s):  
Free Energy ◽  
Experimental Method ◽  
Thermodynamic Functions ◽  
Virial Coefficients ◽  
Heat Content ◽  
Heat Of Fusion ◽  
Partial Pressures ◽  
Pure Benzene ◽  
Good Agreement ◽  
Saturated Solutions

The partial molar heat content, entropy and free energy of benzene in solutions of diphenyl in benzene have been determined by measurement of the partial pressures of benzene over the solu-­ tions. The whole composition range has been covered (as far as the solubility of diphenyl will allow), at temperatures from 30 to 80° C. A check on the accuracy of the experimental method has been made by measuring the vapour pressure of pure benzene over this temperature range, and good agreement has been found with recent values reported in the literature. The calculation of the thermodynamic functions from the vapour pressures requires a knowledge of the compressibility of benzene vapour. An experimental method has been devised for determining the gas imperfections of vapours, and using this the second and third virial coefficients of benzene vapour at various temperatures have been obtained. The variation of the thermodynamic functions of benzene with the composition of the solutions has been compared with that to be expected on the basis of recent statistical theories. It is found that whereas the non-ideal partial molar free energy can be accounted for almost exactly by the theo­ retical expression, the separate heat contents and entropies show some deviations. It is suggested that these deviations arise from slight changes in molecular packing as the composition is varied. The activities of benzene and diphenyl in saturated solutions at 30 to 60° C have been obtained from the vapour pressures of saturated solutions at these temperatures. These lead to values for the latent heat of fusion of diphenyl in agreement with the calorimetric value. The yapour pressure of saturated solutions is discussed.

scholarly journals Thermodynamic simulation of the V-Al-N-C master alloy aluminothermic smelting

2019 ◽  
Vol 59 (9) ◽  
pp. 132-139
Author(s):  
Alexey V. Larionov ◽  
◽  
Denis V. Taranov ◽  
Vladimir M. Chumarev ◽  
Leonid A. Smirnov ◽  
...  
Keyword(s):  
Master Alloy ◽  
Elemental Carbon ◽  
Thermodynamic Simulation ◽  
Equilibrium Temperature ◽  
Point Of View ◽  
Temperature Dependences ◽  
C Complex ◽  
Vanadium Carbides ◽  
Hsc Chemistry ◽  
Good Agreement

For microalloying of titanium with nitrogen and carbon, the V-Al-N-C complex master alloy is used. One of the main requirements presented by consumers of this ligature to its composition is oxygen content of less than 0.1 % mass. The use of elemental carbon (graphite) in the mixture for out-of-furnace aluminothermic smelting of the V-Al-N-C master alloy promotes the formation of aluminum oxonitrides in the melt, which, in the process of forming the metal and slag phases, can be stored in the alloy as separate inclusions. Since carbon in the master alloy is present in the form of V2Al0.96C1.1 carbide, it is advisable to replace graphite in the composition of the smelting mixture with an alternative precursor containing carbide of this composition. The paper presents the results of thermodynamic simulation of phase formation occurring in the process of V-Al-N-C master alloy smelting using various carbidizers. The equilibrium temperature dependences were obtained using the HSC Chemistry 6.12 software, the database of which was supplemented by the missing thermochemical characteristics of vanadium aluminides (VAl3, V5Al8, V3Al2) and V2AlC carbide borrowed from published sources. Thermodynamic models that take into account the formation of these intermetallic compounds adequately describe the processes that occur during the interaction of mixture components for the aluminothermic smelting of V-Al-N-C alloys. The predicted elemental and phase compositions of the V-Al-N-C model alloys are in a good agreement with the data of chemical, XRD and EMPA analyzes of samples of real alloys. Models that take into account the formation of V2AlC carbide and vanadium aluminides are applicable for calculating the compositions and thermality of mixtures, as well as for predicting the V-Al-N-C alloys smelting products. From the point of view of thermodynamics, replacing graphite in a mixture of the V-Al-N-C master alloy smelting with a precursor alloy V(70)-Al(23)-C(7), carbon in which is represented as V2AlC carbide and vanadium carbides V2C and VC, will not affect the carbon distribution over it phase component and will not adversely affect the technological performance of the smelting.

THEORETICAL INVESTIGATIONS ON THE MECHANISM OF ACTIVATION OF AMMONIA BY A p-DIMETHYLAMINOPYRIDINE COORDINATED SI=O DOUBLE BOND

2012 ◽  
Vol 11 (02) ◽  
pp. 437-481 ◽  
Author(s):  
YUN-QING HE ◽  
ZE-QIN CHEN ◽  
YING XUE
Keyword(s):  
Hydrogen Bond ◽  
Free Energy ◽  
Energy Barrier ◽  
Intermolecular Hydrogen Bond ◽  
Free Energy Barrier ◽  
Theoretical Investigations ◽  
Unique Pair ◽  
First Time ◽  
Good Interpretation ◽  
Good Agreement

Recently, Xiong et al. reported an activation of ammonia by p-dimethylaminopyridine (DMAP) coordinated silanone (DMAP→Si(L)=O, DS) affording a unique pair of sila-hemiaminal (SH) and silanoic amide (SA) tautomers (Xiong Y, Yao S, Müller R, Kaupp M, Driess M, J Am Chem Soc132:6912, 2010). In this paper, the mechanisms of the activation of ammonia affording SH and SA, the successive generation of hydrogen bonded complex pair SH–SA and the tautomerization between SH and SA have been intensively investigated computationally for the first time at MP2/6-311+G(2d,p)//B3LYP/6-31+G(d,p) level in toluene. The concerted Paths C and D with ammonia assistance are determined by our calculations to be the dominant pathways corresponding to forming SH and SA from DS, respectively. The free energy barrier of Path C affording SH from DS is 14.45 kcal/mol, and that of Path D affording SA is 21.46 kcal/mol. So it is determined theoretically that Path C is dynamically dominant over Path D. And the pair SH–SA is formed then spontaneously by intermolecular hydrogen bond (O–H ⋯ O′) without any barrier. While the tautomerization between SH and SA is nonsignficant resulting from the corresponding relative high barriers (23.79 kcal/mol for process from SH to SA and 26.52 kcal/mol for process from SA to SH). Our results are in good agreement with and good interpretation of the experimental results by Xiong et al.

scholarly journals Heat Capacities and Thermodynamic Properties of Pinnoite and Inderite

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Hanyu Zheng ◽  
Kangrui Sun ◽  
Long Li ◽  
Yafei Guo ◽  
Tianlong Deng
Keyword(s):  
Free Energy ◽  
Phase Transitions ◽  
Thermodynamic Properties ◽  
Gibbs Free Energy ◽  
Thermodynamic Functions ◽  
High Purity ◽  
Heat Capacities ◽  
Thermal Anomalies ◽  
Natural Minerals ◽  
First Time

In this paper, in order to understand the thermodynamic properties of natural minerals of pinnoite (MgB2O4·3H2O, Pin) and inderite (Mg2B6O11·15H2O, Ind) deposited in salt lakes, heat capacities of two minerals were measured using a precision calorimeter at temperatures from 306.15 to 355.15 K after the high purity was synthesized. It was found that there are no phase transitions and thermal anomalies for the two minerals, and the molar heat capacities against temperature for Pin and Ind were fitted as Cp,m,pin = −2029.47058 + 16.94666T − 0.04396T2 + 3.89409×10−5T3 and Cp,m,Ind = −30814.43795 + 282.68108T − 0.85605T2 + 8.70708×10−4T 3, respectively. On the basis of molar heat capacities (Cp,m) of Pin and Ind, the thermodynamic functions of entropy, enthalpy, and Gibbs free energy at the temperature of 1 K interval for the two minerals were obtained for the first time.

scholarly journals THERMODYNAMIC FUNCTIONS OF FORMATION OF LITHIUM TITANATES

2021 ◽  
Vol 0 (4) ◽  
pp. 60-66
Author(s):  
U.N. Sharifova ◽  
Keyword(s):  
Free Energy ◽  
Enthalpy Of Formation ◽  
Thermodynamic Functions ◽  
Standard Entropy ◽  
Standard State ◽  
Temperature Range ◽  
Lithium Glass ◽  
Binary Compounds ◽  
First Time ◽  
Thermodynamic Functions Of Formation

By the method of electromotive forces measuring concentration chains: Pt│Li2O│ ZrO2+10 wt% Y2O3, lithium glass. (Li2O)x(TiO2)1-x│Pt in the temperature range T=1000–1200K and concentrations 0.35÷0.95 mol fraction TiO2, the thermodynamic functions of the formation of the compounds Li4TiO4, Li2TiO3, Li4Ti5O12 and phases based on Li2TiO3:Li1.92Ti1.04O3.04, Li2.12Ti0.94O2.92 were determined. With the exception of the compound Li2TiO3, the thermodynamic functions of the formation of lithium titanates are deter¬mined for the first time. The thermodynamic functions of formation are calculated for the 1200 K and for the standard state at 298 K. The thermodynamic functions of the formation of lithium titanates are determined from simple substances and from binary compounds Li2O and TiO2. In particular, for the free energy, enthalpy of formation and standard entropy we obtained: ∆G_298^0(Li4TiO4)=–2149 kJ∙mol-1; ∆G_298^0(Li2TiO3)=–1565; ∆G_298^0(Li4Ti5O12)=–5923; ∆H_298^0(Li4TiO4)=–2286 kJ∙mol-1; ∆H_298^0(Li2TiO3)=–1662; ∆H_298^0(Li4Ti5O12)=–6287; S_298^0(Li4TiO4)=119.1 J∙mol-1∙K-1; S_298^0(Li2TiO3)=84; S_298^0(Li4Ti5O12)=315.7

Thanato-Laboratorien. Theorien von Tod und Sterben und Elias Canettis Buch gegen den Tod

2020 ◽  
Vol 4 (1) ◽  
pp. 67-86
Author(s):  
Elisabeth Heyne
Keyword(s):  
Human Life ◽  
Death And Dying ◽  
Point Of View ◽  
Visual Images ◽  
Elias Canetti ◽  
History Of ◽  
Series Of Experiments ◽  
First Time ◽  
Textual Form ◽  
Or History

AbstractAlthough visual culture of the 21th century increasingly focuses on representation of death and dying, contemporary discourses still lack a language of death adequate to the event shown by pictures and visual images from an outside point of view. Following this observation, this article suggests a re-reading of 20th century author Elias Canetti. His lifelong notes have been edited and published posthumously for the first time in 2014. Thanks to this edition Canetti's short texts and aphorisms can be focused as a textual laboratory in which he tries to model a language of death on experimental practices of natural sciences. The miniature series of experiments address the problem of death, not representable in discourses of cultural studies, system theory or history of knowledge, and in doing so, Canetti creates liminal texts at the margins of western concepts of (human) life, science and established textual form.

Geopolitics of Energy

2016 ◽  
Vol 3 (1) ◽  
pp. 78
Author(s):  
Blerina Muskaj
Keyword(s):  
Natural Gas ◽  
Qualitative Methodology ◽  
Scientific Literature ◽  
Point Of View ◽  
Energy Market ◽  
Energy Potential ◽  
Environmental Consequences ◽  
Regional Energy ◽  
Political Debates ◽  
Political Weapon

At the beginning of my paper I will explain the concept of "Geopolitics of Energy", this will be done for a quite simple reason, because I want everyone who can sit to read this article to understand more clearly what is at stake, therefore allow them the comprehension of what is being elaborated bellow at first sight. Geopolitics of energy is a concept that relates to policies choosing exporters to implement on importers, is the policy that has an impact on energy consumption, which includes consumer’s choice in the geopolitical context, taking into account the economy, foreign policy, the safety of energy, environmental consequences and priorities that carries the energy exporter. This concept permits the understanding of how works the politics that undertakes this initiative taking into account natural resources such as: natural gas and oil. Natural gas and oil are two main resources that produce energy but also two main elements on which arises all the topic in the energetics game. For this paper is used qualitative methodology, through which we were able to accomplish this work. I focused on scientific literature, official publications and reports on energy geopolitics. The main aim has been to show how in this decade, energy security is at the center of geopolitical agenda and has become the focus of numerous political debates. Regarding this point of view, Europe is taking the initiative to create a common energy market within the continent by creating projects, in which Albania appears as a new regional energy potential. Russia, which is aiming to play a role in the international arena, is seeking to position itself geopolitically in "its political weapon", hydrocarbon resources, in particular natural gas resources.

A Nabatean port on the Red Sea: note on the pottery finds from al-Qusayr (al-Wajh, Saudi Arabia)

2020 ◽  
Author(s):  
Caroline Durand
Keyword(s):  
Saudi Arabia ◽  
19Th Century ◽  
Red Sea ◽  
Point Of View ◽  
The Other ◽  
Trade Routes ◽  
Other Hand ◽  
Roman Egypt ◽  
Pottery Sherds ◽  
First Time

Al-Qusayr is located 40 km south of modern al-Wajh, roughly 7 km from the eastern Red Sea shore. This site is known since the mid-19th century, when the explorer R. Burton described it for the first time, in particular the remains of a monumental building so-called al-Qasr. In March 2016, a new survey of the site was undertaken by the al-‘Ula–al-Wajh Survey Project. This survey focused not only on al-Qasr but also on the surrounding site corresponding to the ancient settlement. A surface collection of pottery sherds revealed a striking combination of Mediterranean and Egyptian imports on one hand, and of Nabataean productions on the other hand. This material is particularly homogeneous on the chronological point of view, suggesting a rather limited occupation period for the site. Attesting contacts between Mediterranean merchants, Roman Egypt and the Nabataean kingdom, these new data allow a complete reassessment of the importance of this locality in the Red Sea trade routes during antiquity.

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