It is often noted that disordered materials have different chemical properties to their more “ordered” cousins. Quantifying these effects in terms of thermodynamics is challenging in part because disordered materials can be difficult to characterize and are frequently relatively unstable. During the course of our experiments to understand the effects of disorder in catalysts for water oxidation we observed that many disordered manganese and cobalt oxide water oxidation catalysts directly oxidized peroxide in contrast to their more ordered analogues which catalyzed its disproportionation, that is, MnO2+2H+ +H2O2! Mn2+ +2H2O+O2(oxidation) versus H2O2!H2O+1=2 O2(disproportionation). By measuring the efficiency for one reaction over the other as a function of pH, we were able to quantify the relative stability of materials in two series of metal oxides and thereby quantify their relative thermodynamic stability, “by proxy”. We found that for the series of catalysts investigated the disorder made the materials stronger chemical oxidants and worse catalysts for the disproportionation of peroxide
The skill scale in most of sport activity monitoring a lot of dynamic behaviours conducted with playing situations that help the excerpt's in sport field to evaluate and put right solutions ,soccer one of games that studies in third stage in college and take skills ,dribbling , passing, shooting these skills helps to execute the plans in game ,the researchers notice that there is no test measure the skills of the game in the beginning of the first semester especially in the method of soccer in physical education college and the problem of the research were by answering the question that is there test connect between one or more that one of skill to measure the ability of students to execute the plans in soccer and the conclusion was the bui
... Show MoreAbstract The surface of kaolin was diagnosed by an AFM and the results were shown The height of the highest peak reached by a quantity of Kaolin surface is 2.5 µm, the granules, and their diameter with an average diameter of 666.1nm. Using Kaolin's adsorption properties, erythrosine was removed of its aqueous solution. It was determined that the maximal dye adsorption ranged 36.53–40.61%. The results of using the Freundlich, Langmuir, and Temkin adsorption isotherms revealed that at temperatures of (298,308,318) K, the Freundlich model was followed, the Langmuir model did not match, and the Temkin model could only be partially applied. There is also physical adsorption. One of the three kinetic models of the
... Show MoreIn this study, a Hydroxyapatite (HA) coating was prepared on a titanium implant by an electrochemical deposition process. The titanium pre-treatment by anodizing in 1.65 mol/L sulfuric acid with (10V) at room temperature. The deposition was all conducted at a constant voltage of 6.0 V, for 1 h at room temperature. The coatings thus prepared were characterized with Fourier transform infrared spectroscopy (FTIR) and thickness of the coated layer.The electrochemical deposition of HA occurred on the titanium as a cathode. Coated titanium by HA after anodizing revealed a good corrosion protection efficiency even at a temperature ranged (293-323) K in artificial saliva. Activation energy and pre-exponential factor (kinetic parameters) were calcul
... Show MoreCurrent studies interested on the biosynthesis of zinc oxide nanoparticles (ZnO-NPs) using hot plants extracts of Allium sativum and characterization of them using: Atomic Force Microscopy (AFM), X-ray diffractions (XRD), Fourier Transform Infrared Spectroscopy (FT- IR), UV–visible spectral and Hot stage. The results found that all NPs are had nano-size. ZnO NPs was produced by four procedures using hot extract of Allium sativum. The average diameters were: 101.59 nm, 110.33 nm, 75.69 nm, 88.67 nm for first, second, third and fourth procedures respectively compared with 47.57 nm for standard NPs. The Roughness averages (Ra) were: 10.8 nm, 6.83 nm, 13.8 nm, 0.541 nm for first, second, third and fourth respectively. The Root mean square (Sq
... Show MoreBackground: This study was conducted to evaluate the surface roughness and dimensional accuracy of commercially obtainable alginate impression material in terms of imbibition after immersion in two different media. Materials and method: Two disinfecting agents, ethanol 70% and povidone-iodine 4%, were used to access the dimensional accuracy and surface roughness of alginate impression material. Weights of specimen discs of alginate impressions were measured before and immediately after immersion to gain a measure of imbibition. For surface roughness, disinfected specimens rectangle was examined before and after disinfection. Results: Minimal changes in weight were observed after disinfection, but a statistically non-significant differenc
... Show MoreThe subject of an valuation of quality of construction projects is one of the topics which it becomes necessary of the absence of the quantity standards in measuring the control works and the quality valuation standards in constructional projects. In the time being it depends on the experience of the workers which leads to an apparent differences in the valuation.
The idea of this research came to put the standards to evaluate the quality of the projects in a special system depending on quantity scale nor quality specifying in order to prepare an expert system “ Crystal “ to apply this special system to able the engineers to valuate the quality of their projects easily and in more accurate ways.
The effects of the permeation cement grout with fly ash on the sandy soil skeleton were studied in the present work in two phase; first phase the shear strength parameters, and the second phase effect of these grouted materials on volume grouted zone by injection (51) cm³ of slurry in sandy soil placed in steel cylinder model with dimension 15 cm in diameter and 30 cm in height. The soil sample was obtained from Karbala city and it is classified as poorly graded sand (SP) according to USCS. The soil samples were improved by cement grout with three percentages weight of water cement ratio (w:c); (0.1w:0.9c, 0.8w:0.2c, and 0.7w:0.3c), while the soil samples were dehydrated for one day
... Show MoreThe present paper focuses on the study of some characteristics of
comets ions by photometry method which represent by CCD camera
which it provide seeing these images in a graded light. From 0-255
when Zero (low a light intensity) and 255 (highlight intensity). These
differences of photonic intensity can be giving us a curve which
appear from any line of this image.
From these equations the focus is concentrating on determine the
temperature distribution, velocity distribution, and intensity number
distribution which is give number of particles per unit volume.
The results explained the interaction near the cometary nucleus
which is mainly affected by the new ions added to the density of the
solar wind, th