Sintering of Commercial Leucite-Based Dental Porcelains

2008 ◽  
Vol 591-593 ◽  
pp. 692-696
Author(s):  
Cátia Fredericci ◽  
H.N. Yoshimura ◽  
André Luiz Molisani ◽  
C.E. Bellinati ◽  
R.Q.E. Alcântara ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Heating Rate ◽  
Effect Of Temperature ◽  
Surface Microstructure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Increasing Temperature ◽  
Fractured Surface ◽  
Scanning Electron

The aim of this work was to study the effect of temperature and heating rate on the densification of two leucite-based dental porcelains: one low-fusion and one high-fusion commercial leucite porcelains (Dentsply-Ceramco). Porcelain powders were characterized by differential thermal analysis (DTA), X-ray diffraction (XRD), particle size distribution, and helium picnometry. Bar samples were sintered from 650 to 1050oC, using heating rate of 55oC and 10oC/min. Sintered samples were characterized in terms of bulk density, measured by the Archimedes method in water, and fractured surface microstructure by scanning electron microscopy (SEM). The results show that densification increases with increasing temperature and the increase in heating rate has no effect on the densification of the porcelains studied.

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 Structural and thermoelectric properties of the Pr2Zr2O7 compound

2019 ◽  
pp. 4-9
Author(s):  
Adolfo Quiroz-Rodríguez ◽  
Cesia Guarneros-Aguilar ◽  
Ricardo Agustin-Serrano
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Thermoelectric Properties ◽  
Crystal Size ◽  
Ambient Pressure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Increasing Temperature ◽  
Thermal Stability Of ◽  
Scanning Electron

In this research, it is presented a detailed study of the structural and thermoelectric properties of the pyrochlore zirconium Pr2Zr2O7 compound prepared by solid-state reaction (SSR) in air at ambient pressure. The synthesized sample was characterized using powder X-ray diffraction. The thermal stability of the thermoelectric compound (TE) Pr2Zr2O7 was tested by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). Scanning electron microscopy shows that the crystal size varies between 0.69 and 2.81μm. Electrical conductivity (\sigma) of the sample calcined at 1400 °C presented values increase irregularly with the increasing temperature from 0.001 to 0.018 S cm-1 as expected in a semiconductor material. The thermal conductivity is lower than 0.44 - 775 W m-1 K-1 which is quite anomalous in comparison with the thermal conductivity of other oxides.

SIZE-INDUCED EFFECTS IN NANOSTRUCTURED NiFe2O4

2010 ◽  
Vol 24 (30) ◽  
pp. 5973-5985
Author(s):  
M. GUNES ◽  
H. GENCER ◽  
T. IZGI ◽  
V. S. KOLAT ◽  
S. ATALAY
Keyword(s):  
Electron Microscopy ◽  
Annealing Temperature ◽  
Structural Parameters ◽  
Hydrothermal Process ◽  
Lattice Parameter ◽  
Effect Of Temperature ◽  
Vibrating Sample Magnetometer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

NiFe 2 O 4 nanoparticles were successfully prepared by a hydrothermal process, and the effect of temperature on them was studied. The particles were annealed at various temperatures ranging from 413 to 1473 K. Studies were carried out using powder X-ray diffraction, scanning electron microscopy, infrared spectroscopy, differential thermal analysis, thermogravimetric analysis and a vibrating sample magnetometer. The annealing temperature had a significant effect on the magnetic and structural parameters, such as the crystallite size, lattice parameter, magnetization and coercivity.

Reactivity in the chromium oxide-calcium fluoride system: An empirical approach

1999 ◽  
Vol 14 (6) ◽  
pp. 2518-2523
Author(s):  
Frans Vos ◽  
Luc Delaey ◽  
Marc De Bonte ◽  
Ludo Froyen
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Calcium Fluoride ◽  
Reaction Mechanisms ◽  
Sintering Temperature ◽  
X Ray Diffraction ◽  
Powder Mixtures ◽  
Reaction Behavior ◽  
X Ray ◽  
Scanning Electron

The reaction mechanisms observed when sintering loose Cr2O3–CaF2 powder mixtures were analyzed, and the influence of the sintering parameters on the reaction behavior is presented. Using x-ray diffraction (XRD), energy-dispersive spectroscopy (EDS), and differential thermal analysis (DTA) measurements, CaCrO4 was shown to be the reaction product when sintering in air. The reaction occurs in two steps: CaF2 transforms to CaO at the Cr2O3–CaF2 interface, followed by a CaO–Cr2O3 interaction, which creates the reaction product. Scanning electron microscopy (SEM) and x-ray fluorescence (XRF) analysis showed an increasing loss of CaF2 with increasing sintering temperature and heating rate, while an opposite evolution of the amount of reaction product was observed.

Synthesis, Characterization and Magnetism of Nanosized Copper Ferrite

2008 ◽  
Vol 368-372 ◽  
pp. 604-606 ◽  
Author(s):  
Wei Zhong Lv ◽  
Zhong Kuang Luo ◽  
Bo Liu ◽  
Xiang Zhong Ren ◽  
Hong Hua Cai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Copper Ferrite ◽  
Sonochemical Method ◽  
Thermal Gravimetric ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ft Ir ◽  
Scanning Electron

Copper ferrite powders were successfully synthesized by sonochemical method. The resultant powders were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), FT-IR, differential thermal analysis-thermal gravimetric (DTA-TG), differential scanning calorimetry (DSC) and VSM. The particle saturation magnetization (Ms) is 66 emu/g and an intrinsic coercive force (iHc) is 2100 Oe when the precursor calcined at 950 °C for 15 h.

Darstellung und Charakterisierung des Silber(I,II,III)-oxidclathrates Ag7O8HCO3 / Synthesis and Characterization of the Silver(I,II,III) Oxide Clathrate Ag7O8HCO3

2000 ◽  
Vol 55 (9) ◽  
pp. 882-886 ◽  
Author(s):  
Martin Jansen ◽  
Sascha Vensky
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Magnetic Susceptibility ◽  
Solid State Nmr ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

The silver(I,II,III) oxide clathrate Ag7O8HCO3 was synthesized by anodic oxidation of silver(I) in a suspension of Ag2CO3 in an aqueous AgF solution. The title compound was characterized by single crystal X-ray diffraction (cubic, Fm3̄m, a = 9.8085(3) Å, Z = 4), scanning electron microscopy, thermal analysis, IR spectroscopy, 1H-solid state-NMR and measurement of the magnetic susceptibility

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