Presence Of Magnesium Nitrate Research Articles

Mechanical and microstructural properties of lightweight CaO-activated fly ash composites in the presence of magnesium nitrate

The use of industrial by-products is required to replace cement to reduce carbon emission, and it is necessary to secure the strength of cementless binder to satisfy the required mechanical performance. The purpose of this study is to develop a new binder system composed of activated fly ash (FA) with CaO by adding magnesium nitrate ((Mg(NO3)2) as a new additive. To reveal the mechanism of strength enhancement, the influence of the dosage of Mg(NO3)2 on compressive strength, reaction products, and pore characteristics was observed. In addition, expanded perlite (EP) and expanded vermiculite (EV) were mixed in selected samples to develop a lightweight cementless composite. The results showed that adding Mg(NO3)2 significantly increased strength of CaO-activated FA system. In the reaction process, Mg(NO3)2 promoted the solubility of quicklime (CaO) to form more C-(A)-S-H and Ca–Mg–Al-(OH)-NO3-AFm phase and increased the initial concentration of silicon (Si) and aluminum (Al) from FA. The dense C-(A)-S-H formation enhanced mechanical strength by reducing porosity in binder matrix. When EP and EV were mixed in the selected binder, even if the strength decreased as the amount of EP and EV increased, the requirements for the strength and specific gravity of commercial autoclave aerated concrete (AAC) were satisfied.

Rhizopus oryzae AM16; a new hyperactive L-asparaginase producer: Semi solid-state production and anticancer activity of the partially purified protein.

The demand for L-asparaginase is predicted to increase several fold in the future due to its potential clinical applications in the treatment of lymphoid system malignancies and leukemia. Thus identifying suitable sources of production should be considered high priority. Fungi are valuable organisms as they are able to convert what would be considered ‘useless’ materials into materials that have potential value. The present study provides a proof of concept of production of a new hyperactive L-asparaginase producer (Rhizopus oryzae AM16), which was successfully isolated and sequentially optimized using a semi solid-state fermentation method with a simple and cheap medium produced from wheat bran (WB). The fungus was able to produce an appreciable amount of the enzyme (2,875.9 U) after 8 days of incubation under 85.7% moisture, in the presence of magnesium nitrate (5.0 mg N/mg nitrogen per gram of dry WB) at pH 5.8. Testing the anticancer activity confirmed the ability of the resultant enzyme to inhibit the growth of various types of cancer cells (HepG2, MCF-7, HCT and A549). The IC50 values of the dialyzed enzyme were lower than that of the crude product. Thus, this newly identified and purified L-asparaginase may be a promising anticancer drug.

Silver‐Catalyzed Direct C${{_{sp{^{2}}}}}$H Phosphorylation of Indoles Leading to Phosphoindoles

AbstractThe silver carbonate‐catalyzed direct C${{_{sp{^{2}}}}}$H phosphorylation of indoles in the presence of magnesium nitrate is described. The reaction affords selectively phosphonoindoles in moderate to good yields through a radical process. This protocol provides an efficient and general method for the preparation of 2‐ and 3‐phosphorylated indoles.magnified image

Viscoelastic properties and stability of highly concentrated bitumen in water emulsions

Abstract The influence of bitumen concentration, presence of electrolytes, mean droplet diameter and distribution, storage temperature and length of the ethylene oxide chains, on the dynamic shear rheology, of concentrated bitumen in water emulsions, stabilized by nonyl phenol ethoxylated surfactants, was investigated. Emulsions showed a viscoelastic behavior when the bitumen concentration was increased above 60% (v/v). All the emulsions exhibited an increase in the shear modulus when the mean droplet diameter was decreased at a constant volume fraction of bitumen, or when the bitumen volume fraction was increased at a constant mean droplet diameter. The shear modulus became greater when the number of ethylene oxide units in the non-ionic surfactant increased. In all cases studied, the storage temperature and the presence of magnesium nitrate in the aqueous phase promoted a decrease in the values of the viscoelastic parameters. Results are explained on the base of the interaction between the surfactant molecules, adsorbed on adjacent bitumen droplets.

Einflu� von Magnesiumnitrat auf die Trennung von Ytterednitraten in gro�em Ma�stab durch thermische Zersetzung mit nachfolgender stufenweiser Hydrolyse

The separation was studied in the presence of magnesium nitrate and compared with the separation in its absence. As a useful criterion served the expressionA/Z (part of Er in precipitate divided by the degree of decomposition). Under all conditions the separation was significantly better in the presence of magnesium nitrate. The method was used to concentrate the heavy yttrium earths (YE) Er, Tm, Yb and Lu from 38 kg to 10 kgYE 2O3.

Micro Dry Ashing for Trace Selenium Determination in Organic Matrices

Abstract A specific sample treatment method was established for determination of ng levels of Selenium in microquantities of organic compounds. Our task was determination of Selenium traces, in a new pharmaceutical product, as a result of a laboratory scale synthesis, in an amount of several tens of mg. GFAAS was chosen as an analysis method, due to its sensitivity and rapidity. Among the wet and dry methods for organic material digestion tried, the low temperature dry ashing using ashing aid, was the only one which gave satisfactory recoveries of Selenium. Micro dry ashing was performed, using an Ethanol solution of Magnesium Nitrate on samples spiked with Selenium Nitrate in the range of concentration of 1–6ng mg−1 at a temperature of 450°C for two hours. The presence of Magnesium Nitrate and the heating suppress the atomization with approximately 15–25%. Recoveries of Selenium varies as a function of the organic matrix: for polyaromate compounds as Chrysene and Fluoranthene they lie between 90–103% and...

Quantitative determination of lead and cadmium in foods by programmed dry ashing and atomic-absorption spectrophotometry with electrothermal atomisation.

This paper describes the simultaneous determination of lead and cadmium in foods by programmed dry ashing, in the presence of magnesium nitrate, complexing with sodium diethyldithiocarbamate, extraction with isobutyl methyl ketone and atomic-absorption spectrophotometry using the graphite furnace technique. Recoveries are 94–100% for lead and 94–109% for cadmium.

Sulfinates as Nucleophiles for the Ring-Opening of Epoxides: A Convenient Route to β-Hydroxysulfones

Abstract It has been found that the nucleophilic ring-opening of epoxides by arenesulfinates, in the presence of magnesium nitrate as a Lewis acid catalyst, provides a preparatively useful, convenient route to β-hydroxysulfones.

A rapid sensitive method for determining phospholipid phosphorus involving digestion with magnesium nitrate

AbstractA method is described for the rapid determination of phospholipid phosphorus in samples containing less than 0.5 μg phosphorus. Phospholipid phosphorus is first converted to inorganic phosphate by heating a dried lipid extract briefly over a Bunsen flame in the presence of magnesium nitrate, then dissolving the resulting residue in dilute hydrochloric acid at 95 C. The determination of the inorganic phosphate content of the sample then requires only the addition of Triton X‐100 and an acidic ammonium molybdate‐malachite green reagent. Absorbance is measured at 650 nm after 5 min at room temperature.