Products of oxidation at 0°C of mineralogical and artificial graphite—I. Chemical composition, structure and theoretical interlaminar surface area

Carbon ◽  
1969 ◽  
Vol 7 (5) ◽  
pp. 583-588 ◽  
Author(s):  
J. de D. López-González ◽  
A. Martín-Rodríguez ◽  
F. Domínguez-Vega
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...


2020 ◽  
Vol 236 ◽  
pp. 116000 ◽  
Author(s):  
Biljana M. Pejić ◽  
Ana D. Kramar ◽  
Bratislav M. Obradović ◽  
Milorad M. Kuraica ◽  
Andrijana A. Žekić ◽  
...  

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.


2021 ◽  
Vol 316 ◽  
pp. 1019-1024
Author(s):  
O. A. Ignatova ◽  
A. A. Dyatchina

The paper presents the studies’ results of chemical composition, structure, and physico-mechanical properties of high-calcium ashes from the Kansk-Achinsk coals (2017-2019 selection). It was found that ash has a complex poly-mineral composition and contains hydraulically active minerals and oxides of СаОfr, β-C2S, CA, C3A, C4AF, C2F, CaSO4. According to the content of CaOfr, MgO does not meet standards’ requirements. The uniformity of the volume change is maintained by the composition with 50% of cement. The structure and hardening kinetics of ash and ash-cement stone compositions, obtained from the test of normal density, were analyzed. It was established that the hardening of compositions with ash from the Kansk-Achinsk coals was largely influenced by ash minerals. An equivalent amount of cement in composite binders cannot be replaced. In order to obtain a positive effect, compositions with ash instead cement of no more than 30% and a part of fine aggregate, without exceeding the ratio of ash: cement = 1: 1, should be used.


1990 ◽  
Vol 63 (2) ◽  
pp. 221-229 ◽  
Author(s):  
Tuomo Varvikko ◽  
Aila Vanhatalo

The influence of free surface area and pore size of a synthetic-fibre bag, and flow of intestinal substances into the bag, on the intestinal digestion estimates by the nylon-bag method of dry matter (DM), neutral detergent fibre (NDF), nitrogen, NDF-N and feed 15N was studied using a non-lactating cow fed on hay supplemented with barley and oats at maintenance level. The bags containing 15N-labelled ground ryegrass (Lolium perenne), barley, barley straw or rapeseed (Brassica napus) straw were introduced into the duodenum through a T-shaped cannula and collected from the faeces. Also, the disappearance of N from the bag was related to the true intestinal N digestion by comparing it with the net loss between duodenum and faeces of 15N in ryegrass introduced into the duodenum in an aqueous suspension. It was noted that the bag cloth often significantly affected both disappearance values and the subsequent chemical composition of the residues. Re-analysing part of the data as a 2x2 factorial (free surface x pore size) suggested that free surface area was often more important than pore size as a determinant of both disappearance values and chemical composition. Lower apparent (Kjeldahl N) than true (15N) feed N disappearance from the bag suggested a notable proportion of non-feed N in the residues, especially with fibrous feeds with low N. With ryegrass, 15N net loss within the intestine was lower than 15N disappearance from the bags. It was concluded that disappearance of Kjeldahl N is an underestimate of feed N disappearance from bags, but may possibly be an overestimate of the true intestinal digestion of feed N.


2017 ◽  
Vol 82 (12) ◽  
pp. 1417-1431 ◽  
Author(s):  
Marija Vukcevic ◽  
Biljana Pejic ◽  
Ivana Pajic-Lijakovic ◽  
Ana Kalijadis ◽  
Mirjana Kostic ◽  
...  

Waste hemp (Cannabis sativa) fibers were used as sustainable and renewable raw materials for production of low-cost biocarbon sorbent for heavy metals removal. Carbon precursors of different chemical composition were obtained by oxidative and alkaline treatments of hemp fibers. Influence of lignocellulosic precursor chemical composition on hemp fibers-based biocarbon (HFB) characteristics was examined by BET surface area measurement, scanning electron microscopy and mass titration. It was found that lignin content and polymorphic transformation of cellulose increase the SBET of microporous HFBs, while hemicelluloses induce more homogeneous distribution of adsorption active sites. Heavy metal ions adsorption onto HFBs is primarily influenced by the amount of surface oxygen groups, while specific surface area plays a secondary role. Equilibrium data obtained for lead ions adsorption were analyzed by different nonlinear adsorption isotherms, and the best fitting model was chosen using standard deviation and Akaike information criterion (AICC). The maximum adsorption capacities of HFBs ranged from 103.1 to 116.3 mg Pb/g. Thermodynamic parameters showed that Pb2+ adsorption onto HFBs is a spontaneous and complex endothermic process, suggesting the coexistence of physisorption and chemisorption mechanisms.


2016 ◽  
Vol 0 (4(36)) ◽  
pp. 6-27
Author(s):  
М. Б. Галкін ◽  
В. О. Іваниця ◽  
Б. М. Галкін ◽  
Т. О. Філіпова

2021 ◽  
Vol 2144 (1) ◽  
pp. 012004
Author(s):  
P V Panin ◽  
I A Bogachev ◽  
E A Lukina

Abstract Chemical composition, structure, and technological properties have been investigated for metal powder compositions (MPCs) of a new six-component TiAl-based alloy with Gd microadditions: Ti-31.0Al-2.5V-2.5Nb-2.5Cr-0.4Gd, wt.% (Ti-44.5Al-2V-1Nb-2Cr-0.1Gd, at.%). Three MPCs fractions (10–63, 40–100, 80–120 μm) were produced by electrode induction melting and inert gas atomization technique and targeted for the additive synthesis of parts. It is shown that the chemical composition of the MPCs for the main elements corresponds to that of the electrode. In contrast, a 1.5-fold increase of the oxygen content in the MPCs was observed, which is being the result of natural oxidation of powder particles upon air environment due to developed specific surface. It has been determined that the phase composition of the MPCs (γ+α(α2)+β) differs from the equilibrium phase composition of the electrode (γ+α2)+β0/B2) and corresponds to a rapidly quenched metastable state, which indicates high solidification rates in the atomization process, exceeding critical cooling rates of the alloy. The technological properties, specifically the powder flowability, were found to be improved for 40–100 and 80–120 μm fractions, making them applicable for additive synthesis of parts from the studied alloy by selective electron-beam melting method


2021 ◽  
Vol 27 ◽  
Author(s):  
Ranjith Kankala

: Since the inception of nanotechnology, several efforts have been dedicated to fabricating diverse nanodevices with exceptional performance. These innovative constructs have been applied in medicine due to their tailorable physicochemical properties (chemical composition, optical activity, spectra, and charge) and morphological attributes (size, shape, and surface area). Moreover, these versatile nanomedicines could promisingly offer better performance over the conventional therapeutic strategies. Broadly speaking, in terms of chemical composition, nanobiomaterials are classified into two predominant categories of organic and inorganic-based components. Despite their success and enormous versatile advancements in the past two decades, the significant progress towards clinical translation has been hampered by their corresponding intrinsic limitations. In this perspective, we give a brief overview of these organic- and inorganic-based materials, highlighting opportunities and challenges towards their utilization in medicine. Finally, we provide an interesting outlook in lessons learned and looking forward to developing these materials, emphasizing their scope towards clinical translation.


2020 ◽  
Vol 22 (26) ◽  
pp. 15058-15058
Author(s):  
Natalia Kireeva ◽  
Vladislav S. Pervov

Correction for ‘Materials space of solid-state electrolytes: unraveling chemical composition–structure–ionic conductivity relationships in garnet-type metal oxides using cheminformatics virtual screening approaches’ by Natalia Kireeva et al., Phys. Chem. Chem. Phys., 2017, 19, 20904–20918, DOI: 10.1039/c7cp00518k.


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