scholarly journals Modified Carboxymethylcellulose-Based Scaffolds as New Potential Ecofriendly Superplasticizers with a Retardant Effect for Mortar: From the Synthesis to the Application

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3569
Author(s):  
Clotilde Capacchione ◽  
Stephan Partschefeld ◽  
Andrea Osburg ◽  
Rocco Gliubizzi ◽  
Carmine Gaeta
Keyword(s):  
Chemical Nature ◽  
Time Window ◽  
Pore Solution ◽  
Water Soluble ◽  
Cellulose Ether ◽  
Higher Temperature ◽  
Calorimetric Studies ◽  
New Compounds ◽  
Cementitious Systems ◽  
Different Molecular Weight

This article is focused on the research and development of new cellulose ether derivatives as innovative superplasticizers for mortar systems. Several synthetic strategies have been pursued to obtain new compounds to study their properties on cementitious systems as new bio-based additives. The new water-soluble admixtures were synthesized using a complex carboxymethylcellulose-based backbone that was first hydrolyzed and then sulfo-ethylated in the presence of sodium vinyl sulphonate. Starting with a complex biopolymer that is widely known as a thickening agent was very challenging. Only by varying the hydrolysis times and temperatures of the reactions was achieved the aimed goal. The obtained derivatives showed different molecular weight (Mw) and anionic charges on their backbones. An improvement in shear stress and dynamic viscosity values of CEM II 42.5R cement was observed with the samples obtained with a longer time of higher temperature hydrolysis and sulfo-ethylation. Investigations into the chemical nature of the pore solution, calorimetric studies and adsorption experiments clearly showed the ability of carboxymethyl cellulose superplasticizer (CMC SP) to interact with cement grains and influence hydration processes within a 48-h time window, causing a delay in hydration reactions in the samples. The fluidity of the cementitious matrices was ascertained through slump test and preliminary studies of mechanical and flexural strength of the hardened mortar formulated with the new ecological additives yielded values in terms of mechanical properties. Finally, the computed tomography (CT) images completed the investigation of the pore network structure of hardened specimens, highlighting their promising structure porosity.

scholarly journals Change of the cadmium, lead and uranium content in the soil pore water depending on the temperature in conditions of low soil moisture

2019 ◽  
Vol 55 (2) ◽  
pp. 212-222
Author(s):  
G. A. Sokolik ◽  
S. V. Ovsiannikova ◽  
M. V. Papenia
Keyword(s):  
Heavy Metal ◽  
Moisture Content ◽  
Pore Water ◽  
Chemical Nature ◽  
Pore Solution ◽  
Uranium Content ◽  
Iron Hydroxides ◽  
Water Capacity ◽  
Cadmium Lead ◽  
Definite Temperature

Effect of the soil temperature on concentration and total reserve of cadmium, lead and uranium in the interstitial (pore) water of (0–20)-cm samples of sod-podzolic soil with moisture content of 60 % of the water capacity (WC) after their keeping at the definite temperature (in the range of 14–40 °С) was established. It was found that character and extent to which temperature effects on concentration and total reserve of every heavy metal (Cd, Pb, U) in the soil pore solution depended on the chemical nature of heavy metal and peculiarities of soil. In the temperature range of 14–40 °С and moisture content in the soil samples 60 % of the WC, portions of the cadmium, lead and uranium in the soil pore solution decreased in the following way: aCd (0.2–0.4 %) > aPb (0.06–0.07 %) > aU (0.03–0.04 %). The concentrations and total reserves of cadmium, lead and uranium in the soil pore solution increased with lowering the temperature and it was especially true in regard to cadmium. The 5 °С temperature decrease in the range of 14–40 °С caused the content of cadmium in the soil pore solution to increase an average of 25 %, lead – 5.2 and U – 4.6 %. The iron content in the soil solution also increased with decreasing temperature, which indicated a decrease in the sorption capacity of iron hydroxides present in the soil, which probably played a prominent role in fixing cadmium, lead and uranium in the soil studied.

scholarly journals Chemical Characteristics of Major Inorganic Ions in PM2.5 Based on Year-Long Observations in Guiyang, Southwest China—Implications for Formation Pathways and the Influences of Regional Transport

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 847
Author(s):  
Hao Xiao ◽  
Hua-Yun Xiao ◽  
Zhong-Yi Zhang ◽  
Neng-Jian Zheng ◽  
Qin-kai Li ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Inorganic Ions ◽  
Sulfur Oxidation ◽  
Average Concentration ◽  
Water Soluble ◽  
Soluble Ions ◽  
Water Soluble Ions ◽  
Transformation Mechanisms ◽  
Higher Temperature ◽  
Oxidation Ratio

Sulfate, nitrate and ammonium (SNA) are the dominant components of water-soluble ions (WSIs) in PM2.5, which are of great significance for understanding the sources and transformation mechanisms of PM2.5. In this study, daily PM2.5 samples were collected from September 2017 to August 2018 within the Guiyang urban area and the concentrations of the major WSIs in the PM2.5 samples were characterized. The results showed that the average concentration of SNA (SO42−, NO3−, NH4+) was 15.01 ± 9.35 μg m−3, accounting for 81.05% (48.71–93.76%) of the total WSIs and 45.33% (14.25–82.43%) of the PM2.5 and their possible chemical composition in PM2.5 was (NH4)2SO4 and NH4NO3. The highest SOR (sulfur oxidation ratio) was found in summer, which was mainly due to the higher temperature and O3 concentrations, while the lowest NOR (nitrogen oxidation ratio) found in summer may ascribe to the volatilization of nitrates being accelerated at higher temperature. Furthermore, the nitrate formation was more obvious in NH4+-rich environments so reducing NH3 emissions could effectively control the formation of nitrate. The results of the trajectory cluster analysis suggested that air pollutants can be easily enriched over short air mass trajectories from local emission sources, affecting the chemical composition of PM2.5.

On new compounds of carbon and hydrogen, and on certain other products obtained during the decomposition of oil by heat

1833 ◽  
Vol 2 ◽  
pp. 248-249
Keyword(s):  
Low Temperature ◽  
Specific Gravity ◽  
Solid Body ◽  
Low Temperatures ◽  
Transparent Liquid ◽  
Higher Temperature ◽  
New Compounds ◽  
Oil Gas ◽  
Crystalline Mass

The experiments of which the results are detailed in this paper, were made principally on the fluid which is found to be deposited in considerable quantity when oil-gas is compressed. This fluid, as obtained at the works of the Portable Oil-gas Company, is colourless, of a specific gravity less than that of water; insoluble in water except in very minute quantities; soluble in alcohol, ether, oils, &c.; and combustible, burning with a dense flame. It is strikingly distinguished from the oil from which it originated, by not being acted upon to any extent by solutions of the alkalies. Part of this fluid is very volatile, causing the appearance of ebullition at temperatures of 50° or 60°; other parts are more fixed, requiring even 250°, or above, for ebullition. By repeated distillations a series of products were obtained from the most to the least volatile, the most abundant being such as occurred from 170° to 200°. On subjecting these, after numerous rectifications, to a low temperature, it was found that some of them concreted into a crystalline mass, and ultimately a substance was obtained from them, principally by pressure at low temperatures, which upon examination proved to be a new compound of carbon and hydrogen. At common temperatures it appears as a colourless transparent liquid, of specific gravity 0·85, at 60°; having the general odour of oil-gas. Below 42° it is a solid body, forming dendritical transparent crystals, and contracting much during its congelation. At 0° it appears as a white or transparent substance, brittle, pulverulent, and of the hardness nearly of loaf-sugar. It evaporates entirely in the air: when raised to 186° it boils, furnishing a vapour, which has a specific gravity of 40, compared to hydrogen as 1. At a higher temperature the vapour is decomposed, depositing carbon. The substance is combustible, liberating charcoal if oxygen be not abundantly present. Potassium exerts no action upon it below 186°.

Study of Molecular Structure of Water-Soluble Phenolic Resin with Different Molecular Weight by Infrared Spectrum

2014 ◽  
Vol 900 ◽  
pp. 15-19 ◽  
Author(s):  
Xing Lei ◽  
Gui Long Xu ◽  
Jin Yang ◽  
Jian Hu
Keyword(s):  
Molecular Structure ◽  
Molecular Weight ◽  
Infrared Spectrum ◽  
Sodium Hydroxide ◽  
Phenolic Resin ◽  
Addition Reaction ◽  
Early Stage ◽  
Water Soluble ◽  
Structure Of Water ◽  
Different Molecular Weight

Water-soluble phenolic resin was prepared using sodium hydroxide and ammonia as catalysts. The molecular structure of water-soluble phenolic with different molecular weight was studied by infrared spectrum and the mechanism was discussed. The results show that addition reaction and polycondensation synchronize in the reaction process, while addition reaction dominates in the early stage while polycondensation dominates in the later stage.

Rubber and Thioglycolic Acid

1933 ◽  
Vol 6 (1) ◽  
pp. 71-75 ◽  
Author(s):  
Bror Holmberg
Keyword(s):  
Double Bond ◽  
Nitrous Acid ◽  
Thioglycolic Acid ◽  
Water Soluble ◽  
Limited Extent ◽  
Hydrogen Halides ◽  
Carbon Bonds ◽  
New Compounds

Abstract Based on its behavior toward halogens, hydrogen halides, nitrous acid, ozone and hydrogen, rubber has one double bond for each C 5H 8 group. One would therefore expect that it would be possible to obtain from the addition products of these substances new compounds which would throw considerable light on the constitution of rubber. With the exception of the ozonides, however, this is true only to a very limited extent, a fact which depends in part upon the almost complete lack of water-soluble derivatives suitable for further reactions. It is true that the bromide of rubber can be converted by phenols into alkali-soluble compounds, but the carbon bonds of the compounds appear to be formed not only between the components but also by a closing of the ring within the rubber skeleton. Moreover in the transformation of the bromide by triethyl phosphine cyclicization appears to take place. In view of this, the constitution of these derivatives indicates that further work with them would be to little purpose, and as a matter of fact until now almost nothing of any great interest has appeared.

Water-soluble rhodium(II) carboxylate adducts: Cytotoxicity of the new compounds

1996 ◽  
Vol 64 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Aparecido Ribeiro de Souza ◽  
Renato Najjar ◽  
Silvana Glikmanas ◽  
Szulim Ber Zyngier
Keyword(s):  
Water Soluble ◽  
New Compounds

FRACTIONATION OF NITROGEN IN DEVELOPING WHEAT KERNELS

1938 ◽  
Vol 16c (7) ◽  
pp. 263-273 ◽  
Author(s):  
A. G. McCalla
Keyword(s):  
Soluble Protein ◽  
Chemical Nature ◽  
Water Soluble ◽  
Protein Fractions ◽  
Kernel Development ◽  
Protein Nitrogen ◽  
Wheat Kernel ◽  
Water Soluble Protein ◽  
Main Portion ◽  
Wheat Kernels

Total nitrogen in developing wheat kernels was fractionated to give non-protein nitrogen and three protein fractions. Each fraction was hydrolyzed and analyzed for amide and arginine nitrogen.All fractions increased in amide and decreased in arginine nitrogen during kernel development. The main portion of the water-soluble protein is static in nature, and is considered to play no part in the metabolism of the endosperm proteins. The trend, with time, of amide in the two other protein fractions (soluble and insoluble in normal potassium iodide) was closely parallel to the trend of amide in non-protein nitrogen. The chemical nature of each of the gluten fractions in flour from the most insoluble to the most soluble is determined by the chemical nature of successive portions of the non-protein nitrogen in the wheat kernel at progressive stages of maturity.

Selektive Additionsreaktionen an bifunktionalen neutralen Phosphenium-Ion-Komplexen / Selective Addition Reactions of Bifunctional Neutral Phosphenium Ion Complexes

1991 ◽  
Vol 46 (12) ◽  
pp. 1650-1658 ◽  
Author(s):  
Heinrich Lang ◽  
Michael Leise ◽  
Wolfgang Imhof
Keyword(s):  
Triple Bond ◽  
Spectroscopic Data ◽  
Multiple Bond ◽  
Addition Reactions ◽  
X Ray ◽  
Higher Temperature ◽  
New Compounds ◽  
Selective Addition ◽  
C Nmr ◽  
Membered Heterocyclic Compound

The reaction of bifunctional neutral phosphenium ion complexes, containing a carbon-carbon triple bond next to a phosphorus-molybdenum multiple bond, with carbenes and to carbene isolobal organometallic fragments is discussed.So, the reaction of (R)(PhC=C)P=MoCp′(CO), (R = 2,4,6-′Bu3C6H2O; Cp′ = η5-C5H5: la; Cp′ = η5-C5Me5: 1b) with CH2,Ν2 (2) yields the three membered heterocyclic compound (3). 3 reacts with Co2(CO)8 to afford complex (5) in which the phenylethynyl building block is η2-side-on coordinated to a Co2(CO)6 fragment. Similar to the reaction of 1 with 2, 1 forms with Fe2(CO)9 (6), compound (7). In 7 the PMo double bond is coordinated in a η2 fashion to the 16-electron organometallic fragment Fe(CO)4. Using an excess of 6 and a higher temperature, the phosphorus-alkynyl-carbon σ-bond is cleaved, and cluster MoCp*Fe3(CO)8η3-PR)(C≡CPh) (8) is formed.The reaction of 1 with Cr(CO)5(THF) yields 10, a complex, in which the PhC≡C ligand is η2-coordinated to Cp′(CO)2Mo, and the Cr(CO)5 group forms a dative bond with the phosphorus atom.All new compounds have been characterized by analytical as well as by spectroscopic data (IR, 1H, 31P, 13C NMR, MS), compound 10 by an X-ray analysis.

Energy metabolism in the starved new-born lamb

1962 ◽  
Vol 13 (1) ◽  
pp. 144 ◽  
Author(s):  
G Alexander
Keyword(s):  
Energy Metabolism ◽  
Total Energy ◽  
Glycogen Content ◽  
Nitrogen Excretion ◽  
Energy Reserves ◽  
Protein Utilization ◽  
Carbohydrate Reserves ◽  
New Born ◽  
Higher Temperature ◽  
Calorimetric Studies

New-born lambs were treated in one of three ways: (a) killed within 2 hr of birth; (b) starved at 23°C in 'still air'; (c) starved at approximately 9°C in moving air. Starved lambs became hypothermic and hypoglycaemic and lapsed into coma or convulsions shortly before death, which occurred between 16 hr and 5 days. Survival was generally longer when starvation was at the higher temperature. The size of the energy reserves was estimated from the fat and glycogen content of lambs killed at birth or near death from starvation; protein utilization during starvation was estimated from nitrogen excretion in the urine and the increase in urea in the blood. Fat and carbohydrate reserves appeared to be exhausted near death from starvation. Fat was the largest source of energy, and there was twice as much fat available at birth in lambs from well-fed ewes as in lambs from poorly fed ewes. Carbohydrate reserves in the liver and muscle appeared unaffected by pre-natal nutrition. Protein utilization increased progressively throughout starvation at a rate independent of pre-natal nutrition, and the total amount of protein utilized depended on the period of survival. Total energy reserves in lambs from well-fed and poorly fed ewes were approximately 1000 and 400 kcal respectively estimated as above or from calorimetric studies during starvation.

Sign in / Sign up

Export Citation Format

Share Document