scholarly journals Effect of hydrothermal treatment on the structure of an aluminosilicate polymer

2013 ◽  
Vol 11 (5) ◽  
pp. 782-789 ◽  
Author(s):  
Jaroslav Melar ◽  
Vratislav Bednarik ◽  
Roman Slavik ◽  
Miroslav Pastorek
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Treatment ◽  
Structural Changes ◽  
Polycondensation Reaction ◽  
X Ray Diffraction ◽  
Microscopy Imaging ◽  
X Ray ◽  
Crystalline Product ◽  
Amorphous Aluminosilicate ◽  
Scanning Electron

AbstractThe effect of hydrothermal treatment on the structure of an aluminosilicate polymer prepared by a polycondensation reaction between silicate and hydroxoaluminate in alkaline aqueous solution was studied. The structural changes were investigated using X-ray diffraction analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy imaging and thermogravimetric analysis. The results indicated that the amorphous aluminosilicate polymer transformed into a crystalline product during the hydrothermal treatment at 145°C. The crystalline phase was identified as a mineral of the zeolite group, most likely phillipsite. This transformation required an alkaline environment during the hydrothermal treatment.

scholarly journals The Characteristics of Padamarang Magnesite under Calcination and Hydrothermal Treatment

2019 ◽  
Vol 29 (2) ◽  
Author(s):  
Mutia Dewi Yuniati ◽  
Feronika Cinthya Mawarni Putri Wawuru ◽  
Anggoro Tri Mursito ◽  
Iwan Setiawan ◽  
Lediyantje Lintjewas
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Hydrothermal Treatment ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Magnesite (MgCO3) is the main source for production of magnesium and its compound. In Indonesia, magnesite is quite rare and can be only found in limited amount in Padamarang Island, Southeast Sulawesi Provence. Thus the properties of magnesite and the reactivity degree of the obtained product are of technological importance. The aim of this work was to analyze the characteristics of Padamarang magnesite under calcination and hydrothermal treatment processes. The processes were carried out at various temperatures with range of 150-900°C for 30 minutes. The solids were characterized with respect to their chemical and physical properties by using scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). SEM image indicates that magnesite was formed from thin and flat hexagon sheets. The FTIR and XRD analysis disclose that MgO formed at temperature above 300°C, where as the magnesite sample also lost its mass around 50%. These results demonstrate that Padamarang magnesite decomposes to magnesium oxide and carbon dioxide at high temperature.Magnesit (MgCO3) merupakan sumber utama untuk produksi magnesium dan senyawa-senyawanya. Di Indonesia, magnesit cukup jarang dan hanya dapat ditemukan dalam jumlah yang terbatas di Pulau Padamarang, Propinsi Sulawesi Tenggara. Oleh karena itu sifat magnesit dan derajat reaktivitas dari produk-produk magnesit penting untuk diketahui. Penelitian ini bertujuan untuk menganalisis karakteristik magnesit Padamarang dengan perlakuan kalsinasi dan hidrothermal.  Proses dilakukan pada temperatur yang bervariasi dari 150-900°C selama 30 menit. Sifat kimia dan fisika dari magnesit dikarakterisasi dengan menggunakan scanning electron microscopy dengan energy-dispersive X-ray spectroscopy (SEM-EDX), Fourier-transform infrared spectroscopy (FTIR), dan X-ray diffraction (XRD). Gambar dari analisis SEM menunjukkan bahwa magnesit terbentuk dari lembaran-lembaran heksagonal yang tipis dan datar. Hasil analisis dengan FTIR dan XRD menunjukkan bahwa MgO terbentuk pada temperatur diatas 300°C, dimana sampel magnesit juga kehilangan massanya sekitar 50% pada suhu tersebut. Hal ini menunjukkan bahwa Magnesit Padamarang terdekomposisi menjadi magnesium oksida dan karbon dioksida pada temperatur tinggi.

Annealing induced structural changes and microcracking in Mo-Mo3Si

2002 ◽  
Vol 753 ◽  
Author(s):  
X.-L. Wang ◽  
J. H. Schneibel ◽  
Y. D. Wang ◽  
J. W. Richardson
Keyword(s):  
Electron Microscopy ◽  
Experimental Data ◽  
High Temperature ◽  
Structural Changes ◽  
Thermal Stresses ◽  
Annealing Temperature ◽  
Composition Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

ABSTRACTCast Mo-Mo3Si intermetallic composites develop microcracks after annealing at high temperature. Neutron diffraction, x-ray diffraction, composition analysis, and scanning electron microscopy have been used to characterize the structural changes induced by annealing of Mo-Mo3Si. It is shown that the observed cracking cannot be attributed to differential thermal stresses that developed on cooling from the annealing temperature. Instead, the experimental data suggest that the cracks were initiated at high temperature, possibly due to diffusion of Si atoms from supersaturated α-Mo to Mo3Si.

scholarly journals Influence of Various Climatic Conditions on the Structural Changes of Semicrystalline PLA Spun-Bonded Mulching Nonwovens during Outdoor Composting

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 559 ◽  
Author(s):  
Michał Puchalski ◽  
Piotr Siwek ◽  
Nicolay Panayotov ◽  
Małgorzata Berova ◽  
Stanisława Kowalska ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structural Changes ◽  
Climatic Conditions ◽  
First Year ◽  
Wide Angle ◽  
Viscosity Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Second Year ◽  
Scanning Electron

This study analyzed the structural changes of semicrystalline polylactide (PLA) in the form of spun-bonded mulching nonwovens, during outdoor composting. The investigation was carried out at the microstructural, supramolecular and molecular levels using scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD) and the viscosity method, respectively. The obtained experimental results revealed how the popular outdoor composting method, realized under two different European climatic conditions (in Poland and in Bulgaria), affects the degradation of PLA nonwoven, designed for agriculture use. The results showed the insignificant influence of the climatic conditions and prepared compost mixtures on the molecular and micromorphological structure of PLA spun-bonded mulching nonwovens, with a visible increase in crystallinity after the first year of composting. Significant changes were observed only after the second year of composting, which indicates the resistance of semicrystalline PLA to degradation in outdoor composting conditions.

scholarly journals Influence of Various Climatic Conditions on the Structural Changes of Semicrystalline PLA Spun-Bonded Mulching Nonwovens during Outdoor Composting

2019 ◽  
Author(s):  
Michał Puchalski ◽  
Piotr Siwek ◽  
Nicolay Panayotov ◽  
Małgorzata Berova ◽  
Stanisława Kowalska ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Climatic Condition ◽  
Degradation Rate ◽  
Structural Changes ◽  
Climatic Conditions ◽  
Wide Angle ◽  
Viscosity Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

This study analyzed the structural changes of semicrystalline polylactide (PLA) in the form of spun-bonded mulching nonwoven, during outdoor composting. The investigation was carried out at the microstructural, supramolecular and molecular levels using scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD) and the viscosity method, respectively. The results showed the varying degree of influence of the climatic condition, prepared compost mixtures and time on the molecular, supramolecular and micromorphological structure of PLA spun-bonded mulching nonwoven and its degradation rate. The obtained experimental results revealed how the popular outdoor composting method, realized under two different European climatic conditions (in Poland and in Bulgary), affects the degradation of PLA nonwoven, designed for agriculture use.

Synthesis of Nanotubular Titanate from Titanium Using Hydrothermal Treatment

2006 ◽  
Vol 317-318 ◽  
pp. 247-250 ◽  
Author(s):  
T. Kubo ◽  
W. Kato ◽  
Yuki Yamasaki ◽  
Atsushi Nakahira
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Aqueous Solution ◽  
Scanning Electron Microscopy ◽  
Hydrothermal Treatment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesis Conditions ◽  
Transmission Electron ◽  
Scanning Electron

In this study, the synthesis of nanotubular titanate was attempted though heat-treatment in an oil bath (non-hydrothermal treatment), heat-treatment with stirring in an oil bath (non-hydrothermal treatment), or hydrothermal treatment for metal Ti in NaOH aqueous solution systems. Obtained products were characterized by various methods, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). XRD results suggested that products obtained by both hydrothermal treatment and heat-treatment in an oil bath with and without stirring could be identified as H2Ti4O9H2O. From TEM observations, however, various morphologies for products obtained by these treatments were confirmed. Therefore, it was considered that morphologies of these products strongly depended on synthesis conditions.

Identification of calcium oxalate crystals in dried or fixed tobacco leaf

1984 ◽  
Vol 42 ◽  
pp. 288-289
Author(s):  
Vicki L. Baliga ◽  
Mary Ellen Counts
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Calcium Oxalate ◽  
Growth And Development ◽  
Polarized Light ◽  
Calcium Oxalate Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron

Calcium is an important element in the growth and development of plants and one form of calcium is calcium oxalate. Calcium oxalate has been found in leaf seed, stem material plant tissue culture, fungi and lichen using one or more of the following methods—polarized light microscopy (PLM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray diffraction.Two methods are presented here for qualitatively estimating calcium oxalate in dried or fixed tobacco (Nicotiana) leaf from different stalk positions using PLM. SEM, coupled with energy dispersive x-ray spectrometry (EDS), and powder x-ray diffraction were used to verify that the crystals observed in the dried leaf with PLM were calcium oxalate.

Environmental scanning electron microscopy of fresh human gallstones reveals new morphologies of precipitated calcium salts

1992 ◽  
Vol 50 (2) ◽  
pp. 1322-1323
Author(s):  
Howard S. Kaufman ◽  
Keith D. Lillemoe ◽  
John T. Mastovich ◽  
Henry A. Pitt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
X Ray Diffraction ◽  
Calcium Salts ◽  
Cholesterol Gallstones ◽  
X Ray ◽  
Ca Carbonate ◽  
Scanning Electron

Gallstones contain precipitated cholesterol, calcium salts, and proteins. Calcium (Ca) bilirubinate, palmitate, phosphate, and carbonate occurring in gallstones have variable morphologies but characteristic windowless energy dispersive x-ray (EDX) spectra. Previous studies of gallstone microstructure and composition using scanning electron microscopy (SEM) with EDX have been limited to dehydrated samples. In this state, Ca bilirubinates appear as either glassy masses, which predominate in black pigment stones, or as clusters, which are found mostly in cholesterol gallstones. The three polymorphs of Ca carbonate, calcite, vaterite, and aragonite, have been identified in gallstones by x-ray diffraction, however; the morphologies of these crystals vary in the literature. The purpose of this experiment was to study fresh gallstones by environmental SEM (ESEM) to determine if dehydration affects gallstone Ca salt morphology.Gallstones and bile were obtained fresh at cholecystectomy from 6 patients. To prevent dehydration, stones were stored in bile at 37°C. All samples were studied within 4 days of procurement.

Photocatalytic activity of TiO2 synthesized by anodization and anodic spark deposition

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3141-3152
Author(s):  
Alma C. Chávez-Mejía ◽  
Génesis Villegas-Suárez ◽  
Paloma I. Zaragoza-Sánchez ◽  
Rafael Magaña-López ◽  
Julio C. Morales-Mejía ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Surface Characteristics ◽  
Amorphous Solids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Anodic Spark Oxidation ◽  
Porous Surfaces ◽  
Scanning Electron

AbstractSeveral photocatalysts, based on titanium dioxide, were synthesized by spark anodization techniques and anodic spark oxidation. Photocatalytic activity was determined by methylene blue oxidation and the catalytic activities of the catalysts were evaluated after 70 hours of reaction. Scanning Electron Microscopy and X Ray Diffraction analysis were used to characterize the catalysts. The photocatalyst prepared with a solution of sulfuric acid and 100 V presented the best performance in terms of oxidation of the dye (62%). The electric potential during the synthesis (10 V, low potential; 100 V, high potential) affected the surface characteristics: under low potential, catalyst presented smooth and homogeneous surfaces with spots (high TiO2 concentration) of amorphous solids; under low potential, catalyst presented porous surfaces with crystalline solids homogeneously distributed.

The Effect of the Microstructure of Diffusion Barriers on the Palladium Activation for Electroless Copper Deposition

2002 ◽  
Vol 716 ◽  
Author(s):  
Seok Woo Hong ◽  
Yong Sun Lee ◽  
Ki-Chul Park ◽  
Jong-Wan Park
Keyword(s):  
Electron Microscopy ◽  
Diffusion Barriers ◽  
Copper Deposition ◽  
X Ray Diffraction ◽  
Plan View ◽  
X Ray ◽  
Transmission Electron ◽  
Electroless Copper ◽  
Sheet Resistance Measurement ◽  
Scanning Electron

AbstractThe effect of microstructure of dc magnetron sputtered TiN and TaN diffusion barriers on the palladium activation for autocatalytic electroless copper deposition has been investigated by using X-ray diffraction, sheet resistance measurement, field emission scanning electron microscopy (FE-SEM) and plan view transmission electron microscopy (TEM). The density of palladium nuclei on TaN diffusion barrier increases as the grain size of TaN films decreases, which was caused by increasing nitrogen content in TaN films. Plan view TEM results of TiN and TaN diffusiton barriers showed that palladium nuclei formed mainly on the grain boundaries of the diffusion barriers.

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.

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