Derivation of a general formula and a general area method for latent heat via differential thermal analysis

1998 ◽  
Vol 323 (1-2) ◽  
pp. 93-99 ◽  
Author(s):  
En-Yong Ding ◽  
Xue-Hai Liang
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
General Formula ◽  
Latent Heat ◽  
General Area ◽  
Area Method

scholarly journals Comparison of Thermal Analysis and Differential Thermal Analysis for Evaluating Solid Fraction Evolution during Solidification of Al-Si Alloys

2010 ◽  
Vol 649 ◽  
pp. 493-498 ◽  
Author(s):  
Ana Isabel Fernández-Calvo ◽  
Andrea Niklas ◽  
Jacques Lacaze
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Heat Release ◽  
Latent Heat ◽  
Solid Fraction ◽  
Metallic Alloys ◽  
Transfer Model ◽  
Cooling Curves ◽  
Latent Heat Release ◽  
Controlled Cooling

Both thermal analysis (TA) and differential thermal analysis (DTA) have been used since long to evaluate latent heat release and solid fraction evolution during solidification of metallic alloys. TA makes use of cooling curves recorded under "natural" cooling while DTA consists in recording the temperature difference between the sample temperature and an inert reference during a controlled cooling, i.e. at imposed constant cooling rate. In both cases, the solid fraction evolution is deduced from a calculation of the latent heat release as estimated by means of a heat transfer model. This paper provides a comparison of such evaluations performed on one Al-Si alloy.

Energetics of Intramolecular Bonds in 1H-1,2,4-Triazole and 1H-Benzotriazole

1999 ◽  
Vol 52 (4) ◽  
pp. 235 ◽  
Author(s):  
Raphaël Sabbah ◽  
Laurence Perez
Keyword(s):  
Thermal Analysis ◽  
Heat Capacity ◽  
Differential Thermal Analysis ◽  
General Formula ◽  
Triple Point ◽  
Thermodynamic Quantity ◽  
Atomization Enthalpy ◽  
A Value ◽  
Resonance Energies ◽  
Heat Capacity Measurements

This paper deals with a thermodynamic study of 1H-1,2,4-triazole and 1H-benzotriazole (general formula C2H3N3 and C6H5N3 respectively). Investigations were performed by combustion calorimetry of small amounts of substance (a few milligrams), sublimation calorimetry, differential thermal analysis and heat capacity measurements. The experimental combustion, sublimation and fusion enthalpies of the two compounds were determined as well as their triple point temperatures and are as follows: From these results, experimental resonance energies have been obtained and compared with theoretical values. The experimental atomization enthalpy of 1H-1,2,4-triazole is compatible with the calculated value. In the case of 1H-benzotriazole, it was possible to determine from this thermodynamic quantity a value of 298·4 kJ mol-1 for the N=N bond enthalpy.

Energétique des liaisons inter- et intramoléculaires dans les trois isomères de l'aminopyridine

1998 ◽  
Vol 76 (1) ◽  
pp. 18-24 ◽  
Author(s):  
Raphaël Sabbah ◽  
Maria Ermelinda da Silva Eusébio
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
General Formula ◽  
Triple Point ◽  
Relative Stability ◽  
Combustion Calorimetry ◽  
Thermodynamic Study ◽  
Enthalpy Of Combustion ◽  
Resonance Energies

The present work is concerned with a thermodynamic study of the three aminopyridine (AP) isomers (general formula: C5H6N2). It was achieved using three techniques: combustion calorimetry of small amounts of substance (a few milligrams), sublimation calorimetry, and differential thermal analysis. From this study, it was possible to determine the enthalpies of combustion, sublimation, and fusion of these compounds and their triple point temperatures; to discuss the relative stability of the three molecules; to determine the experimental resonance energies and compare them with the theoretical values; to determine the atomization enthalpies and compare them with the values calculated from the energetical contributions previously determined in our laboratory; to determine the enthalpy of the intermolecular bonds.Key words: aminopyridine isomers; enthalpy of combustion, of sublimation, of fusion, of inter- and intramolecular bonds.

Diffraction thermometry and differential thermal analysis

2002 ◽  
Vol 35 (6) ◽  
pp. 664-668 ◽  
Author(s):  
E. H. Kisi ◽  
D. P. Riley
Keyword(s):  
Phase Transition ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Latent Heat ◽  
Unit Cell Parameter ◽  
Powder Diffraction ◽  
Cell Parameter ◽  
Diffraction Method ◽  
Transition Studies

A unit-cell parameter anomaly observed during the precipitation and growth of Ti3SiC2from a Si-substituted TiC phase is interpreted as the release of latent heat. The observations are used to propose a powder diffraction method for conducting differential thermal analysis as part ofin situphase transition studies.

Zeolites Fit For A Crown: Probing Host-Guest Interactions with Thermogravimetric Methods

2018 ◽  
Author(s):  
Asel Sartbaeva ◽  
Paul R. Raithby ◽  
Remi Castaing ◽  
Antony Nearchou
Keyword(s):  
Mass Spectrometry ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Petrochemical Industry ◽  
Rational Use ◽  
New Methodologies ◽  
First Time ◽  
Kinetics Of

Through a combination of thermogravimetry, mass spectrometry and differential thermal analysis, we demonstrate for the first time that all four zeolites show experimental differences in their host-guest interactions with 18C6. In addition, we have estimated the kinetics of 18C6 decomposition, which is a technique that has not been applied to zeolites previously. Using these findings as a toolkit, a more rational use of OSDAs can be utilised to prepare designer zeolites. Furthermore, the new methodologies presented herein can be applied to current zeolites, such as MFI-type zeolites used in the petrochemical industry.

PHASE EQUILIBRIUM IN THE AS2TE3-TM2TE3 SYSTEM.

2020 ◽  
Vol 5 (8(77)) ◽  
pp. 65-68
Author(s):  
Teymur Mammad Ilyasly ◽  
Rahman Hasanaga Fatullazade ◽  
Zakir Islam Ismailov ◽  
Nigar Nadir Jafarova
Keyword(s):  
Thermal Analysis ◽  
Solid Solution ◽  
Differential Thermal Analysis ◽  
Phase Equilibrium ◽  
Physicochemical Properties ◽  
Thermal Effects ◽  
Isothermal Annealing ◽  
Intermediate Phase ◽  
Physicochemical Analysis ◽  
Two Phases

The synthesis of alloys of the system was carried out stepwise in rotary furnaces. The synthesis mode was selected based on the physicochemical properties of the elementary components. For homogenization, the alloys were subjected to isothermal annealing at 750 and 1275 K, depending on the Tm2Te3 concentration, for 250 h after homogenization of the alloys, they were subjected to physicochemical analysis. The results of differential thermal analysis showed that reversible thermal effects are observed in the alloys of the system. In alloys in a 1: 1 ratio, a new intermediate phase is formed with a composition corresponding to the TmAsTe3 compound. The homogeneity area is observed in the concentration range 52.5-47.5. It was found that in the concentration range 98.5-52.5 Tm2Te3 there are two phases - a mixture of β and of the solid solution, and in the concentration range of 47.51 mol% Tm2Te3 phases and α are in equilibrium. ) 66 The eutectic has coordinates of 11.5 mol Tm2Te3 at a temperature of 575 K.

PENINGKATAN LAJU DISOLUSI ACYCLOVIR DENGAN METODE SISTEM DISPERSI PADAT MENGGUNAKAN POLOXAMER 188

2016 ◽  
Vol 5 (1) ◽  
pp. 6
Author(s):  
Budi Setiawan ◽  
Erizal Zaini ◽  
Salman Umar
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Differential Thermal Analysis ◽  
Fourier Transform Infrared ◽  
X Ray Diffraction ◽  
Poloxamer 188 ◽  
X Ray ◽  
Scanning Electron

Sebuah penelitian tentang sistem dispersi padat dari asiklovir dengan poloxamer 188 telah dilakukan formulasi dengan pencampuran secara fisika dengan rasio 1 : 1, 1 : 3, 1 : 5 dan dispersi padat 1 : 1, 1 : 3, 1 : 5 dan penggilingan 1:1 sebagai pembanding. Dispersi padat dibuat menggunakan metode pencairan (fusi), yang digabung dengan poloxamer 188 pada hotplate kemudian asiklovir dimasukkan ke dalam hasil poloxamer 188 lalu di kocok hingga membentuk masa homogen. Semua formula yang terbentuk termasuk asiklovir poloxamer 188 murni dianalisis karakterisasinya dengan Differential Thermal Analysis (DTA), X-ray Diffraction, Scanning Electron Microscopy (SEM), dan Fourier Transform Infrared (FTIR), kemudian pengambilan dilakukan  (penentuan kadar) mengunakan spektrofotometer UV pada panjang gelombang 257,08 nm dan uji laju disolusi dengan aquadest bebas CO2 menggunakan metode dayung. Hasil pengambilan  (penentuan kadar) menunjukkan bahwa semua formula memenuhi persyaratan farmakope Amerika edisi 30 dan farmakope Indonesia edisi 4 yaitu 95-110%. Sedangkan hasil uji laju disolusi untuk campuran fisik 1: 1, dan dispersi padat 1: 1, dan penggilingan 1: 1 menunjukkan peningkatan yang nyata dibandingkan asiklovir murni. Hal ini juga dapat dilihat dari hasil perhitungan statistik  menggunakan analisis varian satu arah  SPSS 17.

Sign in / Sign up

Export Citation Format

Share Document