Reactive molecular dynamics study on localized high-temperature region formation and thermal decomposition of defect-containing β-HMX crystals: influence of different types and concentrations of liquid inclusion defects

The selection of an appropriate demineralizing solution in pathology laboratories depends on several factors such as the preservation of cellularity, urgency of diagnostic and financial costs. The aim of this study was to test different decalcification bone procedures in order to establish the best value of these in formalin-fixed and paraffin-embedded samples. Femurs were removed from 13 adult male Wistar rats to obtain 130 bone disks randomly divided into five groups that were demineralized in different concentrations of nitric acid (Group I); formic acid (Group II); acetic acid (Group III); EDTA, pH7.4 (Group IV) and Morsés solution (Group V). Serial, 3-μm-thick sections were obtained and stained with hematoxylin-eosin to calculate the percentage of osteocyte-occupied lacunae. The sections were also stained with Masson's trichrome in conjunction with picrosirius red under polarized light followed by a semi-quantitative analysis to verify the adjacent muscle-to-bone integrity and preservation of collagen fibres. The highest percentage of osteocyte-occupied lacunae was found with 10% acetic acid solution (95.64 ± 0.95%) and Group I (nitric acid) demanded the shorter time (0.8-5.7days). Of all solutions, 5% nitric acid incurred the lowest cost to achieve complete demineralization compared with other solutions (p < .001). Group IV (EDTA) had the highest integrity of muscle and collagen type I and III (P < 0.01). Demineralization with 10% acetic acid was the most effective at preserving bone tissue, while 5% EDTA was the best at maintaining collagen and adjacent muscle to bone. In conclusion, nitric acid at 5% showed the most efficient result as it balanced both time and cost as a demineralizing solution.

Tri-n-butyl phosphate (TBP) in diluent is generally used as a solvent for the extraction of fissile materials in the reprocessing of spent fuels by the PUREX process. The mutual solubility of TBP and water leads to the transfer of some finite amount of TBP into the aqueous phase. The distribution study of TBP between normal paraffin hydrocarbon (NPH) and nitric acid has been studied. Equilibrium curves have been generated for TBP in different concentrations of nitric acid and NPH. The distribution coefficient (Kd) is also calculated by measuring the concentration of associated TBP in the aqueous and organic phase. The effect of an inert diluent on the solubility of TBP in nitric acid is also studied. It has been found that the distribution coefficient value varies with the concentration of TBP, nitric acid, and NPH. Nitric acid partitioning between TBP and water has also been studied. The concentration of nitric acid in both phases was determined by the titration method. It has also been proven that the c...

Single-walled carbon nanotubes were dispersed in deionized water with sodium dodecyl benzene sulfonate as surfactant. The solutions were sprayed on UV and plasma treated polyethylene terephthalate to achieve transparent conductive films with excellent adhesion. The carbon nanotube films were further treated with different concentrations of nitric acid to improve conductivity. SWCNTs and films were characterized by thermo gravimetric analysis, field-emitting scanning electron microscopy, UV-VIS spectrophotometer, four-point probe method, and Raman spectroscopy. The results demonstrated that the conductivity of carbon nanotube films with high transparency was improved to a greater degree with higher concentration of nitric acid due to effectively removing residual surfactants. The low sheet resistance films of ~100 Ω/sq @ 80T% have widely applications in touch screen, flat panel displays, organic light emitting diode, and etc.

Purpose High corrosion resistance in different concentrations of nitric acid is essential for structural steels to be used for the aqueous reprocessing of spent nuclear fuels with high plutonium content. Design/methodology/approach In the present study, the corrosion resistance of type 304L stainless steel (SS) with modified composition was evaluated in different concentrations of nitric acid using surface analytical techniques, weight loss method and electrochemical measurements. Findings Weight loss measurement in boiling 65 per cent nitric acid showed a low corrosion rate value of about 0.2 mm/y (8 mpy) after 240 h exposure. Electrochemical measurements revealed the shift in open circuit potentials as well as corrosion potential toward more noble direction, and the results of electrochemical impedance spectroscopy studies indicated the reduction in the thickness and stability of the passive film with increasing concentration from 6 to 11.5 M nitric acid. Research limitations/implications The low corrosion rate observed for this steel is attributed to the higher content of Cr (19 per cent), Ni (10 per cent) and Si (0.3 per cent) and controlled minor alloying elements (S, P, B, C, etc.) in the alloy that contributed to improving the transpassive corrosion resistance and minimizing the intergranular corrosion attack. The X-ray photoelectron spectroscopic analysis revealed the composition of the passive films to be mainly of iron and chromium oxides. Practical implications Materials with lower corrosion rates are desirable for applications in nitric acid. Social implications The used of nitric acid creates a severe corrosive environment in chemical or aqueous nuclear reprocessing plants, and hence with a modified composition of type 304L SS resulting in minimizing failure of components are desirable for reducing cost and maintenance. Originality/value The present paper is an original work carried out by the authors on the corrosion resistance behaviors of composition modified AISI type 304L SS for nitric acid application. The effects of different nitric acid concentrations were compared to provide understanding on in applicability in boiling and high nitric acid concentrations.

TISSUE INTEGRITY AND TIME ASSOCIATED WITH DIFFERENT AGENTS FOR BONE DEMINERALIZATION

The partitions of uranium (vi) and thorium between nitric acid solutions and kerosene solutions of tri‐n‐butyl phosphate (TBP) have been investigated at different concentrations of nitric acid and solvent and at different temperatures. An infra‐red spectral study has also been made of the organic solutions obtained.

The partition of uranium (VI) between nitric acid solutions and organic solutions of long‐chain aliphatic amines has been investigated at different concentrations of nitric acid and solvent, and at different temperatures. The effects of amine structure and of organic solvent and the mechanism of uranium extraction are discussed on the basis of the results obtained. It is postulated, from infrared spectroscopy measurements, that the complex formed in the extraction of uranium (VI) from nitric acid solution by tri‐n‐dodecylamine in benzene is a nitrato complex of uranium.

The partition of uranium (VI) between nitric acid solutions and benzene solutions of some cyclohexyl‐ and benzyl‐alklamines has been investigated at different concentrations of nitric acid and solvent, and at different temperatures. An infra‐red spectral study has also been made of the organic solutions obtained. The mechanism of uranium extraction in this system is discussed on the basis of the results obtained.

The partition of thorium between nitric acid solutions and the solutions of some cyclohexyl‐ and benzyl‐alkylamines in benzene has been investigated at different concentrations of nitric acid and solvent, and at different temperatures. The extraction of nitric acid by these amines in benzene has also been examined. Further an infra‐red spectral study has been made of the organic solutions obtained. The mechanism of thorium extraction in this system is discussed on the basis of the results obtained.

Corrosion characteristics of some commercially pure aluminum alloys (1060, 1100, 3003, and 5052) in different concentrations of nitric acid have been studied at different temperatures. Alloy 3003 exhibits maximum corrosion in all the acid concentrations followed by 5052, 1100, and 1060 alloys. The corrosion rate of aluminum is found to increase and decrease with time in 20 and 70% acid solutions, respectively. In the concentration range of 20–50% of the acid, all the alloys exhibited slightly passivating tendency during the potentiostatic anodic polarization. The breakdown potential of the alloys varies inversely with temperature, whereas an invariable enobling in steady‐state corrosion potential with rise in temperature is noted. The current density required for initiation of passivation, i.e. is related to temperature bywhere and are constants. The alloys exhibited negative steady‐state corrosion potentials in a concentration range of 1–58% of the acid, but above this concentration positive values of the potentials have been noted. Variation of corrosion rates of the different alloys in different concentrations of the acid has been discussed in the light of the presence of different alloying elements. The influence of the addition of 0.025M, 0.05M, 0.1M, 0.25M, and 0.5M chloride, bromide, iodide, acetate, citrate, sulfate, and nitrate as their sodium salts has also been investigated on the anodic dissolution of 1060 alloy in 20% nitric acid. At concentrations of 0.025M, 0.05M, and 0.1M, Cl−, Br−, and I− have little noticeable effect, but at concentrations of 0.25M and 0.5M of the former two compounds very fast corrosion was recorded and the last compound appeared to be a corrosion inhibitor. The tolerable concentration of chloride ion increases with increase in the concentration of nitric acid in conformity withAcetate, citrate, sulfate, and nitrate ions inhibit the dissolution of the alloy at all the concentrations used. It has been concluded that the sodium ion does not affect the dissolution tendency of the alloy and the anions are solely responsible for inhibiting the dissolution of the metal.

Some studies have shown that the operating state of silicone rubber insulators is not only affected by surface corona discharge, but also different due to the surface covered with different pollutants, but few studies have linked the two. In this paper, by designing the corona discharge test of silicone rubber insulator, the output of nitric acid from its surface product was calculated, and the concentration of nitric acid under different air humidity was obtained. The solubility test of slightly dissolved salt calcium sulfate in nitric acid solution at 293.15K and 333.15K was designed to obtain the solubility of calcium sulfate at different concentrations of nitric acid at two temperatures. Finally, a quantitative analysis of the solubility of calcium sulfate on the surface of insulator FXBW-10/70 in nitric acid solution shows that the surface contamination of insulator with good hydrophobicity may be completely dissolved by nitric acid solution, but the surface of insulator with loss of hydrophobicity cannot be completely dissolved by nitric acid. This study provides a theoretical basis for the dissolution characteristics of silicon rubber insulator corona discharge on its surface soluble salt composition and provides a new idea for the influence of insulator corona discharge on its electrical properties.

Studies on the anode catalysts of carbon nanotube for DMFC

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Anion exchange of some elements in acetic acid-hydrochloric acid medium

Cement connection of loess is an important internal factor of loess collapse, which has a direct impact on the sensitivity of the collapse. In this study, different concentrations of nitric acid were added into the immersion water solution of loess collapsibility test. The collapsibility deformation and stability time were measured under different pressure and acid environment. The test results show that: in acid solution, the collapsibility coefficient of collapsible loess increases more under low pressure, and the collapsibility stability time is prolonged under all levels of pressure; Loess has different collapsibility sensitive pressure range in aqueous solution and acidic solution. The structural strength of collapsible loess has an important influence on the depth of collapsible loesr. It is very important to the constructions on the loess area