scholarly journals The specific surface area and chemical composition of diamond dust near Barrow, Alaska

Author(s):  
Florent Domine ◽  
Jean-Charles Gallet ◽  
Manuel Barret ◽  
Stéphan Houdier ◽  
Didier Voisin ◽  
...  
Author(s):  
Changjian Xie ◽  
Yuhui Ma ◽  
Peng Zhang ◽  
Junzhe Zhang ◽  
Xiaowei Li ◽  
...  

With the increasing environmental application and discharge of nano cerium dioxide (nano-CeO2), it is urgent to fully understand its ecotoxicological effects on the aquatic environment. This study for the first...


2011 ◽  
Vol 415-417 ◽  
pp. 1265-1272
Author(s):  
Wen Biao Zhang ◽  
Wen Zhu Li ◽  
Bing Song Zheng

Miscanthus is a highly productive, rhizomatous, C4 perennial grass that should be considered as an excellent active carbon precursor. This paper compares the charcoal characterization and chemical composition between M. sinensis and M. floridulus. Species differed in water content, hot water extract, 1% NaOH extract, organic solvent extract, cellulose, lignin and ash. Carbonization temperatures have effects on charcoal yields of Miscanthus, which ranged from 23.5% to 48.0% for M. sinensis and 11.3% to 37.2% for M. floridulus. Water content, charcoal density, pH value, and specific surface area of charcoal characterization varied between two species of Miscanthus. The specific surface area increased with the increase of carbonization temperature. The highest specific surface area of M. sinensis and M. floridulus was 351.74 m2g−1and 352.74 m2g−1, respectively, when the carbonization temperature was 800°C.


2012 ◽  
Vol 512-515 ◽  
pp. 2434-2438
Author(s):  
Quan Xiao Liu ◽  
Wen Cai Xu

In this paper the comparison among some papermaking powder properties are studied. It shows that the properties of different powders are different because of different chemical composition and different preparation method and their particle size is different for different purpose such as filler and pigment. The particle size of powder for pigment powder is smaller than that for filler. The specific surface area of papermaking filler is lower than 20m2/g, the absorption value of DBP is about 45cm3/100g, the whiteness is up to 90%, and the particle size is about 3µm. The specific surface area of papermaking pigment is lower than 25m2/g, the absorption value of DBP is from 40 cm3/100g to100cm3/100g, the whiteness of clay is up to 50%, the whiteness of GCC and PCC is up to 90%, and the particle size is lower than 2µm. The specific surface area of silica is up to 100m2/g, the absorption value of DBP is up to 100cm3/100g, the whiteness is up to 97%, and the particle size is around 5µm.


2017 ◽  
pp. jn241927
Author(s):  
Lidija Posavec ◽  
Florentine M Hilty ◽  
Jeannine Baumgartner ◽  
Hylton Buntting ◽  
Monika Hilbe ◽  
...  

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Dariusz Smoleń ◽  
Tadeusz Chudoba ◽  
Stanisław Gierlotka ◽  
Aleksandra Kedzierska ◽  
Witold Łojkowski ◽  
...  

A microwave, solvothermal synthesis of hydroxyapatite (HAp) nanopowder with a programmed material resorption rate was developed. The aqueous reaction solution was heated by a microwave radiation field with high energy density. The measurements included powder X-ray diffraction (PXRD) and the density, specific surface area (SSA), and chemical composition as specified by the inductively coupled plasma optical emission spectrometry technique (ICP-OES). The morphology and structure were investigated using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A degradation test in accordance with norm ISO 10993-4 was conducted. The developed method enables control of the average grain size and chemical composition of the obtained HAp nanoparticles by regulating the microwave radiation time. As a consequence, it allows programming of the material degradation rate and makes possible an adjustment of the material activity in a human body to meet individual resorption rate needs. The authors synthesized a pure, fully crystalline hexagonal hydroxyapatite nanopowder with a specific surface area from 60 to almost 240 m2/g, a Ca/P molar ratio in the range of 1.57–1.67, and an average grain size from 6 nm to over 30 nm. A 28-day degradation test indicated that the material solubility ranged from 4 to 20 mg/dm3.


Revista CERES ◽  
2019 ◽  
Vol 66 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Maria Maiara Cazotti ◽  
Liovando Marciano da Costa ◽  
Paulo Roberto Cecon

ABSTRACT Liming acid soils is fundamental for agricultural activity such as the study and characterization of alternative liming material. The objective of this study was to characterize biological, sedimentary, and metamorphic limestones. The following limestones were studied: biogenic (BL), sedimentary (SL), commercial (CL), and marble (ML). This study evaluated total relative neutralizing power (TRNP), chemical composition, specific surface area, and Ca2+and Mg2+release at concentrations of 0.10, 0.50, 1.00, and 2.00 mol L-1 HCl, in addition to the effects on the soil 90 days after limestone application. The Si identified contributed to the lower TRNP of BL (73.7%) and CL (74.4%). At the lowest HCl concentrations, BL was the most reactive, but with an increase in concentration, ML became the most reactive. The highest CaO (58.32%) and MgO (13.05%) levels were observed in SL and ML, respectively, which contained the highest Ca2+(3.95 cmolcdm-3) and Mg2+ (1.09 cmolcdm-3) concentrations when applied to the soil. All the limestones increased pH and lowered soil H+Al. Soil Ca2+and Mg2+were influenced by the composition of the amendments.


2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Seok Woo Chang

Chemical composition and porosity characteristics of calcium silicate-based endodontic cements are important determinants of their clinical performance. Therefore, the aim of this study was to investigate the chemical composition and porosity characteristics of various calcium silicate-based endodontic cements: MTA-angelus, Bioaggregate, Biodentine, Micromega MTA, Ortho MTA, and ProRoot MTA. The specific surface area, pore volume, and pore diameter were measured by the porosimetry analysis of N2 adsorption/desorption isotherms. Chemical composition and powder analysis by scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) were also carried out on these endodontic cements. Biodentine and MTA-angelus showed the smallest pore volume and pore diameter, respectively. Specific surface area was the largest in MTA-angelus. SEM and EDS analysis showed that Bioaggregate and Biodentine contained homogenous, round and small particles, which did not contain bismuth oxide.


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