ADSORPTION OF CYCLOHEXANE AND BENZENE ON MIXED HYDROXIDES AND OXIDES OF MAGNESIUM AND ALUMINIUM

1966 ◽  
Vol 44 (8) ◽  
pp. 877-884 ◽  
Author(s):  
R. I. Razouk ◽  
Sh. Nashed ◽  
F. N. Antonious
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermogravimetric Analysis ◽  
Surface Area ◽  
Structural Changes ◽  
Mixed Oxides ◽  
X Ray Diffraction ◽  
Oxide Systems ◽  
X Ray ◽  
Characteristic Lines

Seven mixed hydroxides of magnesium and aluminium were prepared, and phase and structural changes accompanying their dehydration were investigated by differential thermal analysis, thermogravimetric analysis, and X-ray diffraction techniques. The differential thermal analysis curves possess 2 peaks corresponding to those of parent hydroxides together with a new peak, and the thermogravimetric analysis curves show slight inflections. X-ray diffraction patterns of the mixed hydroxides possess the characteristic lines of the parent hydroxides together with three to five new intense lines which might indicate the formation of a double hydroxide. When the mixed hydroxides are progressively heated they give rise to products possessing patterns which first become diffuse and ultimately pass mainly into the spinel pattern.Adsorption isotherms of cyclohexane and benzene were measured on the mixed hydroxides and their dehydration products. Specific surface areas calculated by the application of the Brunauer, Emmett, Teller (B.E.T.) equation are in general in good agreement for the two adsorbates. The surface area increases with rise of dehydration temperature to a maximum at 500–600 °C and then decreases with further rise in temperature. This behavior is common to crystalline oxide systems and may be ascribed to the intermingling of decomposition, re-crystallization, and sintering processes. Variations in the molecular ratio of the mixed oxides (as much as 20-fold), and in the method of preparation, do not much alter the surface area.

Vacuum Carburization of Nanometer Tungsten Powder with Carbon Black

2007 ◽  
Vol 534-536 ◽  
pp. 165-168 ◽  
Author(s):  
Luo Ji ◽  
Lin Tao ◽  
Zhi Meng Guo ◽  
Cheng Chang Jia
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Surface Area ◽  
Tungsten Powder ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Vacuum Carburization ◽  
Dta Curves

Vacuum carburization of nanometer tungsten powder was investigated in a simple designed apparatus. An X-Y recorder was used to plot differential thermal analysis (DTA) curves to determine the starting temperature of carburization of four samples with different specific surface area. The product was characterized by X-ray Diffraction (XRD) and small angle X-ray scattering (SAXS). The results show that finer tungsten powder has lower starting temperature of carburization. Tungsten powder, the BET surface area of which is 32.97m2/g, was completely carburized to tungsten carbide at 1050°C, even though the starting temperature was 890°C. The particle was found to grow sharply before carburization.

Synthesis of Nanocrystalline Fe25Al57.5Ni17.5 by Mechanical Alloying

2012 ◽  
Vol 476-478 ◽  
pp. 1318-1321
Author(s):  
Qi Zhi Cao ◽  
Jing Zhang
Keyword(s):  
Thermal Analysis ◽  
Solid Solution ◽  
Differential Thermal Analysis ◽  
Mechanical Alloying ◽  
Ball Mill ◽  
Structural Changes ◽  
Early Stage ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray

Nanostructured Fe25Al57.5Ni17.5intermetallics was prepared directly by mechanical alloying (MA) in a high-energy planetary ball-mill. The phase transformations and structural changes occurring in the studied material during mechanical alloying were investigated by X-ray diffraction (XRD). Thermal behavior of the milled powders was examined by differential thermal analysis (DTA). Disordered Al(Fe,Ni) solid solution was formed at the early stage. After 50 h of milling, Al(Fe,Ni) solid solution transformed into Al3Ni2，AlFe3，AlFe0.23Ni0.77 phase. The power annealed at temperature 500 results in forming of intermetallics AlFe3 and FeNi3 after 5h milling. The nanocrystalline intermetallic compound was obtained after 500h milling.

The Effect of H3BO3 Microaddition on Microstructure of Ni/MgO Sintered Compact by Co-Precipitation Method

2013 ◽  
Vol 750 ◽  
pp. 168-171
Author(s):  
Ning Ning Zhou ◽  
Dong Ying Ju ◽  
Wan Yu Ding
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermogravimetric Analysis ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Sintered Compact ◽  
X Ray ◽  
Sintered Powder ◽  
Co2 Flow ◽  
Co Precipitation

In the present work, Ni/MgO powder was prepared by co-precipitation in which CO restore NiO to elemental subtance Ni due to C2O42- was decompose to CO and CO2 at 700°C. As the process of the second sintering, H3BO3 was added into the sintered powder of 700°C and was grinded. Then the powder of H3BO3 added was sintered at 800°C，so that the powder was refined, obviously. Thermogravimetric analysis (TGA) and differential thermal analysis(DTA) was carried out in CO2 flow at 10°C/min. X-ray diffraction (XRD) was carried out on a X-ray diffractometer operated at 20KV and 40mA. The microstructures and morphologies were studied by EPMA and XPS.

scholarly journals The products of selenite hydrothermal treatment in lithium chloride solutions

2000 ◽  
Vol 65 (4) ◽  
pp. 265-274
Author(s):  
Slobodanka Marinkovic ◽  
Aleksandra Kostic-Pulek ◽  
Mirjana Djuricic
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermogravimetric Analysis ◽  
Microscopic Examination ◽  
Atmospheric Pressure ◽  
Calcium Sulphate ◽  
Infrared Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Calcium Sulphate Hemihydrate

Selenite was boiled in LiCl solutions of different concentrations (1 M, 2 M, 3 M, 4 M and 5M) at the respective boiling temperatures and atmospheric pressure. The products were subjected to X-ray diffraction analysis, qualitative infrared analysis, differential thermal analysis, thermogravimetric analysis and microscopic examination. The product obtained in the 1 M LiCl solution was the ?-form of calcium sulphate hemihydrate (?-CaSO4.0.5H2O). In more concentrated LiCl solutons, 2M and 3 M, the ?-form of calcium sulphate hemihydrate (?-CaSO4.0.5H2O) was formed. The product obtained in the 4MLiCl solution was also the ?-form of calcium sulphate hemihydrate, only mixed with the ?-form of calcium sulphate (?-CaSO4). Finally, in the 5 M LiCl solution the ?-form of calcium sulphate or ?-anhydrite was formed.

Structural, Optical and Thermal Characterizations of Lithium Borate Glasses Containing the Barite

2019 ◽  
Vol 397 ◽  
pp. 24-38 ◽  
Author(s):  
K. Abdellaoui ◽  
I.Z. Hager ◽  
Hosam A. Othman ◽  
A. Boumaza ◽  
Najoua Kamoun
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Glass Transition ◽  
Structural Changes ◽  
Borate Glasses ◽  
Lithium Borate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Amorphous Nature ◽  
F Center

A glass system was prepared according to the formula 60mol%B2O3 – x mol %barite – (40-x) mol %Li2O, where x=0, 5, 7.5, 10, 15 and 20 mol%. The amorphous nature of the prepared glasses was confirmed through X-ray diffraction. The prepared glasses were also characterized by FTIR spectroscopy, UV-vis absorption spectroscopy and the differential thermal analysis (DTA). The density is found to increase and this is because of the higher molecular of the added barite. The molar volume also increases with increasing barite content that indicates the structural changes occurred in borate network that were also confirmed using FTIR. Increasing the concentration of barite shifts the UV cutoff edge toward higher wavelengths from about 300 nm at 0 mol% barite to about 400 nm at 15 mol% of barite. Glass transition temperature (Tg) is found to increase with the increasing barite content. When analyzed by photoluminescence, the samples exhibit luminescence emission centered at around 400, 415, 480, 430, 485, 520, 545, and 570 nm when excited at 300 nm wavelength. The emission peaks at 420 nm, and 440 nm were assigned to F center emission. Between 440 nm and 520 nm it is rather the effect of the presence of the impurities.

scholarly journals Characterisation of the Mural Paintings from the Misericordia Church of Odemira (Portugal)

2008 ◽  
Vol 587-588 ◽  
pp. 1019-1023
Author(s):  
Sara Valadas ◽  
Deolinda Tavares ◽  
João Coroado ◽  
António Santos Silva ◽  
Jorge Pedro ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermogravimetric Analysis ◽  
Chemical Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mural Paintings ◽  
Microchemical Analysis ◽  
Lime Mortars ◽  
Local Sources

Several mortars from mural paintings were collected from the Misericórdia Church of Odemira and analysed by using different techniques namely X-ray diffraction, thermogravimetric analysis with differential thermal analysis, SEM-EDX, optical microscopy, CHNS elemental analysis and chemical analysis. Microfragments of paint layers were collected and analysed by microchemical analysis. The results showed that the mortars are aerial lime mortars with siliceous aggregates and that the pigments used were mainly pigments from local sources (red and yellow ochre’s and malachite) and small blue.

Identification and Thermal Stability of Copper(I) Sulfate

1972 ◽  
Vol 50 (23) ◽  
pp. 3872-3875 ◽  
Author(s):  
Kim Vo Van ◽  
Fathi Habashi
Keyword(s):  
Thermal Stability ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Thermogravimetric Analysis ◽  
Diffraction Pattern ◽  
Chemical Processes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Stability Of

Anhydrous CU2SO4 was prepared and its X-ray diffraction pattern was established. Differential thermal analysis, thermogravimetric analysis, and X-ray diffraction methods were used to study the effect of heating in different atmospheres. The formation of CU2SO4 as an intermediate in chemical processes has been discussed.

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.

scholarly journals The Potential for Natural Stones from Northeastern Brazil to Be Used in Civil Construction

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 440
Author(s):  
Fabiana Pereira da Costa ◽  
Jucielle Veras Fernandes ◽  
Luiz Ronaldo Lisboa de Melo ◽  
Alisson Mendes Rodrigues ◽  
Romualdo Rodrigues Menezes ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Chemical Resistance ◽  
Mechanical Analysis ◽  
Northeastern Brazil ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chemical Agents ◽  
Natural Stones

Natural stones (limestones, granites, and marble) from mines located in northeastern Brazil were investigated to discover their potential for use in civil construction. The natural stones were characterized by chemical analysis, X-ray diffraction, differential thermal analysis, and optical microscopy. The physical-mechanical properties (apparent density, porosity, water absorption, compressive and flexural strength, impact, and abrasion) and chemical resistance properties were also evaluated. The results of the physical-mechanical analysis indicated that the natural stones investigated have the potential to be used in different environments (interior, exterior), taking into account factors such as people’s circulation and exposure to chemical agents.

The Roman Ceramics of Salobrena (Granada-Spain) and their Raw Materials

1992 ◽  
Vol 267 ◽  
Author(s):  
Ana M De Andres ◽  
Isabel MuÑOZ
Keyword(s):  
Thermal Analysis ◽  
Differential Thermal Analysis ◽  
Raw Materials ◽  
Third Century ◽  
Western Coast ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Third ◽  
Good Number ◽  
Scanning Electron

ABSTRACTNineteen roman ceramic sherds found near Salobreña (Granada, Spain), in the western coast of the Mediterranean Sea, as well as different ceramic clays from the surroundingsare studied. Both clays and ceramic sherds are characterizad by X-ray diffraction and spectrometry, differential thermal analysis, and scanning electron and optical microscopies. A good number of the ceramic pieces, among which some “Terrae Sigillatae”, have a composition similar to that of the local clays and, thus, have been probably manufactured at Salobreña. Only a few of them have a foreign origin. For most of them, the firing temperature was about 800-850 °C, although some have been produced at 900-1000 °C, and some others at 1000-1100 °C. It is concluded that Salobreña appearsto have been an important settlement just in the third century of the Christian era.

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