Addition Of Metal Compounds Research Articles

Oil-based drilling fluid inspired by paints recipes

Modifying the oil properties by heating it in presence of inorganic or hybrid materials is a very common practice used in different fields including painting. To improve the drying and rheological properties of oil binders, ancient recipes mention the addition of metal compounds while heating; pigments can then be ground in such treated oils to be used as a paint. The process of forming a gel system using pigments and oil paint medium has significant similarities to the method of formulating oil-based drilling fluids in the petroleum industry. Taking inspiration from this process, the oil-based drilling fluid was successfully prepared by stirring together organoclay and linseed oil under high temperature. The structure and rheology of organoclays containing Na+ and Zn2+ in linseed oil were compared. The rheological tests evaluated the properties of the oil-based drilling fluid, specifically focusing on its suitability for drilling operations. XRD and TEM highlighted the structure of the organoclay and the self-assembly of platelets induced by the clay layers exfoliation. The results indicated that the combination of linseed oil and organic clay exhibited favorable rheological behavior and viscoelastic properties, showing its great application potential in the field of drilling fluids.

The role of metal compounds in dynamically regulating alkali infiltration during pickling of preserved eggs

This study was conducted to investigate the dynamic regulation of alkali infiltration by different metal compounds during the pickling of preserved eggs. With the increased pickling time, the alkalinity of the pickling solution decreased, while the pH of preserved egg white increased firstly, then decreased, and finally increased again. The metal ions corresponding to the added metal compounds (CuSO4, CuSO4/ZnSO4 and PbO) underwent a complex migration with pickling time, and their content gradually increased in eggshell and yolk, but showed complex changes in egg white. The addition of metal compounds could produce a plugging effect. The main components of the black spots on eggshells of preserved eggs pickled by CuSO4, CuSO4/ZnSO4, and PbO were Cu2S, Cu2S/ZnS and PbS, respectively. In short, different metal compounds were combined with H2S to form insoluble compounds to block eggshell stomata, mesh pores and corrosion pores, thereby dynamically regulating the penetration of alkali.

Comparison of subcutaneous inflammatory response to commercial and engineered zinc hydroxyapatite implants in rabbits

ABSTRACT Hydroxyapatite (HA) is widely used as a biomaterial for bone repair and metallic prostheses coating. The main limitations of the current commercial synthetic hydroxyapatite compounds include high cost and decreased availability, especially for veterinary medicine purposes. Additionally, it is thought that HA biocompatibility and bioactivity could be enhanced by the addition of metal compounds. The objective of this work was to compare the subcutaneous tissue response of commercial and engineered hydroxyapatite obtained from the bovine femur diaphysis mixed with different concentrations of hexa-hydrated Zinc Nitrate in rabbits. Twenty-Five New Zealand female rabbits were used. Five treatments were done according to HA composition (commercial HA, no Zn-HA, 0.1M Zn, 0.2M Zn, and 0.3M Zn). Each treatment was evaluated at five time-points (8, 15, 30, 60 and 90 days post-implantation). Histopathologic analysis was performed to assess inflammation by polymorphonuclear cells infiltration, neovascularization, and fibrosis. Results obtained in this work suggest that general inflammation decreased after 60 days of implantation regardless of Zn concentration. Fibrosis score was increased in the commercial HP compared to control and Zn-hydrated HA. This paper shows that bovine hydroxyapatite is a biocompatible material regardless of nitrate Zinc concentration and has the same properties of commercial hydroxyapatite.

Attapulgite as natural catalyst for glucose isomerization to fructose in water

Fructose is generated from glucose isomerization in water over attapulgite without any addition of metal compounds. The formation of fructose was related closely to the calcination processing of attapulgite. The highest fructose yield of 20.6% was obtained with the selectivity of 77.9% over attapulgite calcined at 500°C. Moreover, attapulgite was characterized by BET, XRD, IR and CO2-TPD techniques. The results indicated that proper distribution and amount of basic sites were crucial for the selectivity of fructose as well as the structural properties of attapulgite.

Optimizing the sensitivity and radiological properties of the PRESAGE® dosimeter using metal compounds

The aim of this study is to investigate the radiation-modifying effects of incorporating commercially available bismuth-, tin- and zinc-based compounds in the composition of the PRESAGE® dosimeter, and the feasibility of employing such compounds for radiation dose enhancement. Furthermore, we demonstrate that metal compounds can be included in the formulation to yield water-equivalent PRESAGE® dosimeters with enhanced dose response. Various concentrations of the metal compounds were added to a newly developed PRESAGE® formulation and the resulting dosimeters were irradiated with 100kV and 6MV photon beams. A comparison between sensitivity and radiological properties of the PRESAGE® dosimeters with and without the addition of metal compounds was carried out. Optical density changes of the dosimeters before and after irradiation were measured using a spectrophotometer. In general, when metal compounds were incorporated in the composition of the PRESAGE® dosimeter, the sensitivity of the dosimeters to radiation dose increased depending on the type and concentration of the metal compound, with the bismuth compound showing the highest dose enhancement factor. In addition, these metal compounds were also shown to improve the retention of the post-response absorption value of the PRESAGE® dosimeter over a period of 2 weeks. Thus, incorporating 1–3mM (ca. 0.2wt%) of any of the three investigated metal compounds in the composition of the PRESAGE® dosimeter is found to be an efficient way to enhance the sensitivity of the dosimeter to radiation dose and stabilize its post-response for longer times. Furthermore, the addition of small amounts of the metal compounds also accelerates the polymerization of the PRESAGE® dosimeter precursors, significantly reducing the fabrication time. Finally, a novel water-equivalent PRESAGE® dosimeter formula optimized with metal compounds is proposed for clinical use in both kilovoltage and megavoltage radiotherapy dosimetry.

Effects of Lignin−Metal Complexation on Enzymatic Hydrolysis of Cellulose

This study investigated the inhibition of enzymatic hydrolysis by unbound lignin (soluble and insoluble) with or without the addition of metal compounds. Sulfonated, Organosolv, and Kraft lignin were added in aqueous enzyme-cellulose systems at different concentrations before hydrolysis. The measured substrate enzymatic digestibility (SED) of cellulose was decreased by 15% when SL was added to a concentration of 0.1 g/L due to nonproductive adsorption of enzymes onto lignin. Cu(II) and Fe(III) were found to inhibit enzymatic cellulose hydrolysis in the presence of lignin. Ca(II) and Mg(II) were found to reduce or eliminate nonproductive enzyme adsorption by the formation of lignin-metal complex. The addition of Ca(II) or Mg(II) to a concentration of 10 mM can almost completely eliminate the reduction in SED caused by the nonproductive enzyme adsorption onto the lignins studied (SL, OL, or KL at concentration of 0.1 g/L). Ca(II) was also found to reduce the inhibitive effect of bound lignin in pretreated wood substrate, suggesting that Ca(II) can also form complex with bound lignin on pretreated solid lignocelluloses. Significant improvement in SED of about over 27% of a eucalyptus substrate produced by sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) was achieved with the application of Ca(II).

Experimental Studies on Water Mist Suppression of Liquid Fires with and without Additives

The purpose of this article is to examine the effect of additives on the extinguishment of liquid pool fires with water mist. Tests are conducted using gasoline, diesel, and ethanol pool fires in a 3.0 × 3.0 × 3.0 m well ventilation compartment. The additives included representative kinds of metal compound, NaHCO3, film-forming agent, AFFF, and a multi-component agent, MC additive. Results showed that the suppression performance varied greatly depending on fuel type, additive type, and concentration. The higher the fire point, the easier it is to extinguish the hydrocarbon liquid pool fires with water mist. But for the polar fuel, small fractal flames existing around the pool edge after the fire is suppressed increased the suppression difficulty. The benefit of adding film-forming additives is observed in the suppression of hydrocarbon fires when forming a thin film layer by fluorinated surfactant on the surface. However, too much film-forming additive decreased the marginal fire extinguishing effectiveness due to the saturation effects of surfactants. Addition of a small quantity of film-forming additives did not improve the performance of water mist for ethanol fires, which is considered to be eroded by the fuel. Addition of metal compounds increased the effectiveness of water mist gradually both for ethanol and hydrocarbon fires, but there also existed upper agent limit because of the associated limiting vapor pressure of the active metal compound. The multi-component additive showed a combined suppression effect of film-forming agent and metal chemicals. It effectively extinguished both ethanol and hydrocarbon fires though coupling the physical and chemical fire suppression mechanisms and seems worth further exploration.

Pore control of porous carbons by addition of metal compounds

Pore control of porous carbons by addition of metal compounds

Pore control of porous carbons by addition of metal compounds

Pore control of porous carbons by addition of metal compounds

Activation and transfer of oxygen—IX : Nonenzymic hydroxylation of phenylalanine by model systems of dihydroalloxazine/O 2 dihydroalloxazine/H 2O 2 and alloxazinium cation/H 2O

Efficient hydroxylations were effected without addition of metal compounds. In the dihydroalloxazine system HO· radicals were the hydroxylating species according to the stoichiometry and the distribution of the hydroxyphenylalanine isomers. The OH radicals were generated in one-electron reductions of A R-OOH or H 2O 2, in which a dihydroalloxazine or a semiquinone acted as the reducing agent. The yield of hydroxylation varied in dependence on the further oxidation of the hydroxycyclohexadienyl radicals. Quantitative disproportionation occurred in 6N H 2SO 4, while an attack by O 2, H 2O 2 or A R-OOH predominated in the pH region 0–7. The influence of a HO- consuming aliphatic compound e.g. EDTA was studied. Hydroxylating species are also formed in the attack of an alloxazinium cation by H 2O 2, depending on the acidity of the medium.

Activation and transfer of oxygen. V. Spontaneous oxidation of 1,3,10‐trimethyl‐5,10‐dihydroalloxazine in acidic media in connection with its hydroxylating ability

AbstractOn autoxidation several dihydroalloxazines show a strong hydroxylating ability without addition of metal compounds. The assumption in the literature that N1 ‐alkylated dihydroalloxazines (I) cannot activate oxygen was proved to be wrong. The material balance was studied both in the absence and in the presence of phenylalanine as a substrate. Both autoxidation and hydroxylation to tyrosines were in agreement with calculations based on a theory which has already been put forward.Hydroxylation of organic compounds may be inhibited by some inorganic anions. An explanation is given for the inhibition occurring in hydrochloric acid.