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Oxygen K-edge X-ray absorption spectroscopy is used routinely to study a range of solid materials. However, liquid samples are studied less frequently at the oxygen K-edge due to the combined challenges of high-vacuum conditions and oxygen contamination of window materials. A modular sample holder design with a twist-seal sample containment system that provides a simple method to encapsulate liquid samples under high-vacuum conditions is presented. This work shows that pure silicon nitride windows have lower oxygen contamination than both diamond- and silicon-rich nitride windows, that the levels of oxygen contamination are related to the age of the windows, and provides a protocol for minimizing the background oxygen contamination. Acid-washed 100 nm-thick silicon nitride windows were found to give good quality oxygen K-edge data on dilute liquid samples.

Until recently, sulfur was known as a "spectroscopically silent" element because of a paucity of convenient spectroscopic probes suitable for in situ chemical speciation. In recent years the technique of sulfur K-edge X-ray absorption spectroscopy (XAS) has been used extensively in sulfur speciation in a variety of different fields. With an initial focus on reduced forms of organic sulfur, we have explored a complementary X-ray based spectroscopy - sulfur Kβ X-ray emission spectroscopy (XES) - as a potential analytical tool for sulfur speciation in complex samples. We compare and contrast the sensitivity of sulfur Kβ XES with that of sulfur K-edge XAS, and find differing sensitivities for the two techniques. In some cases an approach involving both sulfur K-edge XAS and sulfur Kβ XES may be a powerful combination for deducing sulfur speciation in samples containing complex mixtures.

Considering the need for housing in recent decades as one of the most basic human needs, and in line with the country's major policies and the importance of home in the religion of Islam, Thus, the emphasis on the principles of housing architecture design, according to the Islamic epistemic system, seems to be an important and indispensable factor in achieving the desired quality of housing. Thus, the present study seeks to answer the question of how well the original Islamic and Qur'anic concepts have been able to be expressed in contemporary physical and functional dimensions in the context of contemporary housing patterns. While explaining the components of Islamic value in the field of housing architecture, in this regard, this research will be done through a combination of two main steps. In the first step, by descriptive-analytical research method and by gathering information in the form of library and documentary studies with the help of first-rate religious sources (Quran Majid), he will extract religious concepts and then specialize the concepts according to the theoretical foundations of research. In the second step, we will evaluate and prioritize the indicators presented in the analytical model from the experts' point of view and evaluate the same indicators in the case samples by fuzzy hierarchy (AHP) technique. The results show that architectural patterns derived from Qur'anic concepts and teachings can be classified into two domains of functional and physical architecture components in Islamic housing. According to the experts, the sub-components of "location" and "geometry" with the weights of 0.217 and 0.275 have the highest importance factor in the functional and physical components, respectively.

Organic sulfoxides, a group of compounds containing the sulfinyl S[double bond, length as m-dash]O group, are widespread in nature, important in health and disease, and used in a variety of applications in the pharmaceutical industry. We have examined the sulfur K-edge X-ray absorption near-edge spectra of a range of different sulfoxides and find that their spectra are remarkably similar. Spectra show an intense absorption peak that is comprised of two transitions; a S 1s → (S-O)σ* and a S 1s → [(S-O)π* + (S-C)σ*] transition. In most cases these are sufficiently close in energy that they are not properly resolved; however for dimethylsulfoxide the separation between these transitions increases in aqueous solution due to hydrogen bonding to the sulfinyl oxygen. We also examined tetrahydrothiophene sulfoxide using both the sulfur and oxygen K-edge. This compound has a mild degree of ring strain at the sulfur atom, which changes the energies of the two transitions so that the S 1s → [(S-O)π* + (S-C)σ*] is below the S 1s → (S-O)σ*. A comparison of the oxygen K-edge X-ray absorption near-edge spectra of tetrahydrothiophene sulfoxide with that of an unhindered sulfoxide shows little change, indicating that the electronic environment of oxygen is very similar.

Aryl and mixed aryl-alkyl organic sulfides are important species in a variety of fields, including the drug and food industries. They also are present in fossil fuels, where they contribute to the range of sulfur compounds that must be removed by the fuel industry. We have used sulfur K-edge X-ray absorption spectroscopy, in combination with density functional theory calculations, to study the aryl sulfide diphenyl sulfide and two different aryl-alkyl sulfides. The sulfur K near-edge X-ray absorption spectra are strongly affected by the coordination of the phenyl ring and are distinct from spectra of the alkyl sulfides. For diphenyl sulfide the spectra are predicted to be sensitive to rotation about the S-C bonds, with experimental spectra corresponding to a sum of thermally accessible conformations. We also have investigated the vapor-phase spectrum of diphenyl sulfide, which is found to be very similar to that of toluene solutions of the compound.

An impedance-based Point Defect Model (PDM) was developed for the potentiostatic, anodic formation of gold oxide at potentials of 1.40–1.70 V vs SHE in H2SO4 (0.1 M and 0.5 M). Film thickness and refractive indices were determined at each oxide formation potential using spectroscopic ellipsometry. The thickness of the oxide increases linearly with increasing potential. Mott-Schottky analysis shows that the oxide exhibits both n-type and p-type character and the dominant defect density is calculated to be in the order of 1021−1022 (1 cm−3). The PDM was optimized upon experimental EIS data to extract values for model parameters and accounts well for the experimental observations in both the steady-state time and frequency domains.

Inhibition of Type 304 L SS corrosion in 0.5 M HCl by New Fuchsin is reported using potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) techniques. The study was complemented by DFT calculations and Monte Carlo simulation (MCS), and the data were interpreted in terms of the Point Defect Model (PDM) and the Anion-Catalyzed Active Dissolution Model (ACADM). Both account for the experimental data. DFT and MCS simulation show that aromatic rings and -NH2 groups interact with the Cr2O3 surface and the inhibitor adopts a lateral configuration on the surface.

Corrosion and time–dependent oxide film growth on AA5052 Aluminum alloy in 0.25M Na2SO4 solution containing H2O2 was studied using electrochemical impedance spectroscopy, potentiodynamic polarization, chronoamperometric and open circuit potential monitoring. It was found that sequential addition of H2O2 provokes passivation of AA5052 which ultimately thickens the oxide film and brings slower corrosion rates for AA5052. H2O2 facilitates kinetics of oxide film growth on AA 5052 at 25° and 60 °C which is indicative of formation of a thick barrier film that leads to an increment in the charge transfer resistance. Pitting incubation time increases by introduction of H2O2 accompanied by lower pitting and smoother surface morphologies. At short exposure (up to 8 h) to H2O2–containing solution, the inductive response at low frequencies predominantly determined the corrosion mechanism of AA5052. On the other hand, at prolonged exposure times (more than 24 h) to 0.25M Na2SO4+1vol% H2O2 solution, thicker oxide layers resulted in the mixed inductive–Warburg elements in the spectra.

Magnesium and its alloys are nowadays one of the most common biodegradable materials for orthopedic applications. Following the implantation of an orthopedic device, near the implant hydrogen peroxide and acidic environment are generated by an inflammatory reaction. In this study, a betamethasone sodium phosphate (BSP) layer as an anti-inflammatory drug was prepared on plasma electrolytic oxidation (PEO) coatings by a dip-coating process on magnesium alloys. X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR), field emission scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy (FESEM-EDX) and atomic force microscopy (AFM) were utilized for characterization studies. The results showed that the BSP layer successfully sealed the PEO coating. The corrosion resistance of the uncoated and coated samples was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests in normal and simulated inflammatory conditions. During the simulated inflammation, the samples indicated an enhanced corrosion rate compared to that of normal condition. The results in the inflammatory environment showed that the corrosion resistance of the PEO/BSP coating was remarkably improved by two or three orders of magnitude, compared with uncoated Mg alloy and the PEO coating. Immersion tests show that the BSP layer significantly improves the bioactivity of PEO-coated Mg alloy in simulated body fluid (SBF). Moreover, the in vitro release behavior of drug loaded PEO coating was evaluated.

Polydopamine (PDA) coating on a copper surface was successfully prepared using a two-step process. In the first stage, in order to improve the adhesion of PDA on the copper surface, a self-assembled monolayer of L -cysteine was deposited on a bare copper. Thereafter, the PDA coating was fabricated through the chemical adsorption and auto-polymerization of the dopamine hydrochloride on the L -cysteine-coated copper surface. The inhibitory behavior of L -cysteine and PDA films has been investigated in aqueous 3.5% NaCl solution using potentiodynamic polarization and electrochemical impedance spectroscopy. It is demonstrated that the L -cysteine/PDA coating provides significant protection against copper corrosion.

The technology that is being developed in Sweden for the disposal of high level nuclear waste calls for storage of the waste in copper canisters, which are encapsulated in a bentonite buffer contained in drill holes in the floors of drifts (tunnels) in a granitic rock repository. A controversial issue has arisen during the development of this technology: that copper, when in contact with pure water under anoxic conditions corrodes and hence is not immune as previously believed. This issue is resolved in the present paper by deriving corrosion domain diagrams as a means of presenting the thermodynamics of the system in the clearest form possible, when assessing the immunity and activation of copper.

article i nfo Inthisstudy,cobaltdisulfide (CoS2)nanoparticleshavebeensuccessfullysynthesizedthrougha simpleandfacile solvothermal method. The experiments were carried out based on the thermodynamic calculations using FactSage software. The black nano-sized CoS2 powder has been produced in an autoclave reactor. The reaction parameters, such as the ratio of primary salts, effect of solvents, temperature and surfactant were optimized to obtain fine and uniform nanoparticles. The band gap energy of the samples was measured with butler relations. The results proved the production of highly pure CoS2 nanoparticles with a semi-spherical morphology.

Passivity breakdown and pitting on pure copper, the assumed material for the outer canisters for the isolation of high-level nuclear waste in Sweden and Finland, has been studied in simulated, sulfide- and chloride-containing granitic rock groundwater and the data are interpreted in terms of the Point Defect Model (PDM). The near normal distribution in the critical breakdown potential (Vc) measured in deaerated sodium sulfide solutions with different chloride concentrations and for variable pH (= 8-10) is in satisfactory agreement with the quantitative prediction of the PDM. The critical areal concentration of condensed cation vacancies at the metal/film interface that leads to passivity breakdown, as predicted by the PDM from the experimental dependence of the Vc on the square root of the voltage sweep rate, ξ

In this work, sol–gel derived bioactive glass/zirconium titanate coatings were uniformly deposited on stainless steel orthopaedic implants, by using carboxymethyl cellulose as a particulate dispersant in the sol. The surface features, wetting, and in vitro electrochemical corrosion behaviour of the coated samples were evaluated. It was found that, by applying the coating on the substrate, the water contact angle was decreased, which is indicative of an improvement in the implant hydrophilicity. Also, the coating improved the corrosion resistance of the metallic implant, as realised by an increase in the corrosion potential and a decrease in the corrosion current density. Indeed, this coating acted as a physical protective barrier which retards the electrolyte access to the metal surface and thereby electrochemical processes.

In this paper, we describe the use of Volt-Equivalent Diagrams (VEDs) to display the electrochemical thermodynamics of one of the most complicated chemical systems in nature; the S–H 2 O system, as it relates to the use of copper for the isolation of high level nuclear waste (HLNW) in granitic repositories in Sweden. The complexity stems from this element having oxidation states that vary from −2 to +8 including a multitude of fractional oxidation states. The volt equivalent describes the reactivity of a species and foretells the various chemical transformations that may occur between different sulfur-containing species in the system.

The growth and properties of the passive films on iron in EDTA (ethylene diamine tetra-acetic acid, disodium salt)-containing borate buffer solution of pH = 8.15 were investigated using in-situ Spectroscopic Ellipsometry (SE), Mott-Schottky analysis, and X-ray photoelectron spectroscopy (XPS). EDTA effectively suppressed the formation of the outer layer of the passive film, thereby rendering the barrier layer amenable to direct examination. It was shown that the barrier layer growth was completed in about 10 s upon stepping the potential in the anodic direction. Contrariwise, thinning of the barrier oxide layer upon stepping the potential in the cathodic direction occurred at a rate that was two orders in magnitude lower than the growth rate. The information obtained above was interpreted in terms of the Point Defect Model (PDM) containing both oxygen vacancies and cation interstitials, with the latter being the dominant defect in the barrier layer.

Commercially available software for optimizing models to empirical impedance data are lacking in many regards. The models are commonly limited at worst to a set of predefined library of analogous, non-physically modeled impedance circuits and at best, limited to what can be programmed by the user within predetermined constraints. Thus, the optimization algorithms are limited in the number of model parameters that can be handled, meaning that the software is incapable of fitting more complicated models, such as the faradaic impedance predicted by the point defect model for the passive state[1-3]. Historically, the point defect model (PDM) faradaic impedance has been optimized on empirical data using gradient-based, nonlinear least squares methods, such as the Levenberg-Mardquardt method. Because the solution space of the point defect model is a 10-30 dimensional hypercube containing a multi-modal optimal surface of solution vectors, it is highly unlikely to obtain a fit solution corresponding to a global minimum in error using gradient-based methods, unless a near-perfect starting guess is employed. It is for this reason that the PDM is so difficult for researchers to use in their own work, often resulting in attempts at using the PDM to be either discarded, or of accepting a generally poor fit quality. Indeed, the screening criteria used for determining the quality of a fit with such methods is often done entirely by “eye” and is therefore highly subjective. It is also highly likely, even with a large number of random samples of starting guesses, to obtain a fit whereby there are alternative solutions with superior agreement. As previously noted, excellent starting guesses must be provided to the algorithm in order to obtain a satisfactory fit, meaning the solution must be known prior to attempting a curve-fit, which is particularly difficult and in many cases intractable. This is often done by using, as the initial guesses for the parameter values, the results of prior optimizations when changing only one independent parameter in a series of experiments (e.g., the passive film formation potential). Improving the fit over subsequent trials of a gradient method was generally accomplished by trial-anderror starting guesses input by the user, or by utilizing a linear grid-based set of starting conditions, evaluating the goodness of fit and choosing the best result. Furthermore, the all-inclusive point defect model has up to 30 parameters, meaning that due to software limitations, many assumptions were required in order to formulate the problem to fit in order to reduce the number of parameters to the limit, generally, 10 parameters, resulting in an incomplete search space, which, depending on the assumptions, could affect the scientific conclusion of the fit. The only advantage of gradient methods is that they are extremely fast. Now that the computational power of desktop computers have outpaced this hurdle, it is necessary to take a new approach for optimizing physico-chemical models, such as the PDM, on experimental impedance data. To this end, custom software has been developed adapting differential evolution[4] to the problem of impedance model optimization. It is currently being used by researchers at Penn State to fit impedance data to a degree of quality never before seen[5-6], with the ability to directly compare the dominance and efficiency of models, for example, a comparison of various diffusion impedance elements as seen in Figure 1

The prediction of corrosion damage to times that are experimentally inaccessible by a large factor (e.g., to over 1000 years) is vitally important in assessing various concepts for the disposal of High Level Nuclear Waste. Such prediction can only be made using deterministic models, whose predictions are constrained to being “physically real” by the natural laws [conservation of mass, energy, charge and mass-charge equivalence (Faraday’s Law)]. In this paper, we describe the measurement of experimental data that will allow the deterministic prediction of damage to the carbon steel overpack of the super container in Belgium’s proposed Boom Clay repository by using the Point Defect Model to extrapolate damage to future times. We also describe an experimental program that is designed to generate values for various PDM parameters for the corrosion of carbon steel and stainless steel that will be required in making the damage predictions.

The prediction of corrosion damage to times that are experimentally inaccessible by a large factor (e.g., to over 1000 to 1,000,000 years) is vitally important in assessing various concepts for the disposal of High Level Nuclear Waste (HLNW). Such prediction can only be made using deterministic models, whose outputs are constrained to being “physically real” by the time- and space-invariant natural laws [conservation of mass, energy, charge and mass-charge equivalence (Faraday’s Law)]. In this paper, we explore the long-term passivity behavior of carbon steel in contact with concrete pore water solution at 80 ◦ C [sat. Ca(OH)2 + sufficient NaOH to yield pH25C = 13.5] by modeling the electrochemical impedance spectroscopic behavior using the Point Defect Model. As a result, we developed a single set of kinetic parameters that might be used, in order to predict the accumulation of general corrosion damage to the supercontainer in Belgium’s HLNW clay repository. The results of the optimization indicate that iron interstitials are the dominant defects in the defective barrier oxide layer and that the diffusivity of the defect calculated to be ≈10 −15 cm 2 s −1 .

The corrosion and cell viability behaviors of nanostructured, nickel-free stainless steel implants were studied and compared with AISI 316L. The electrochemical studies were conducted by potentiodynamic polarization and electrochemical impedance spectroscopic measurements in a simulated body fluid. Cytocompatibility was also evaluated by the adhesion behavior of adult human stem cells on the surface of the samples. According to the results, the electrochemical behavior is affected by a compromise among the specimen's structural characteristics, comprising composition, density, and grain size. The cell viability is interpreted by considering the results of the electrochemical impedance spectroscopic experiments.

One of the centers that have high sensitivity for design is psychotherapy center because of special physical, mental and sentimental conditions of their patient. Design and architecture of psychotherapy centers and caring mental patients are new subjects in our country; and there was no attempt to study and design of this center by interior specialist. To start design of every usage, recognition of habitants of that place is necessary. Recognition and understanding of different needs of Schizophrenic patients and attempt to meet their needs and respect to priority of these needs in designing and improving their special spaces can be effective in improvement of its quality. Schizophrenia is a chronic and debilitating illness which is associated with impaired social and occupational skills and it affects approximately one percent of the population. Since these patients are considered one of the most disadvantaged sectors of society, and their main requirement is to help them to return home and social environment, it should be possible to step in improving treatment by identifying and using elements of environmental quality and to introduce the environment of a hospital as a healing environment not as an environment for permanent or long-term accommodation for patients, Because the main purpose of admission of a mental schizophrenic patients is maintenance of security of patients and others and above all is his stable treatment. But psychotherapy centers in Iran cannot fully respond to the needs of these patients. And most buildings in the old psychiatric institutions are without proper space and occupational therapy sectors are not efficient and effective. The subject of this paper is the eclectic and interdisciplinary, means architecture and psychology. Purposes of that are obtaining a codified agreement, design standards and present an architectural pattern for treatment and positive influences on mental disorders of schizophrenic patients and his return to a normal life.

Passivity breakdown and pitting on carbon steel, the material for the overpack holding the waste canister inside high-level nuclear waste supercontainer in Belgium, has been studied in simulated concrete pore solution (SCPS) with a pH of 13.5 and the data are interpreted in terms of the Point Defect Model (PDM). The near normal distribution in the critical breakdown potential (V c) measured in deaerated SCPS with different chloride concentrations is in satisfactory agreement with the quantitative prediction of the PDM. The critical areal concentration of condensed cation vacancies at the metal/film interface that leads to passivity breakdown, as predicted by the PDM from the experimental dependence of the V c on the square root of the voltage sweep rate, ξ 16 cm−2, is in excellent agreement with that calculated from the unit cell dimensions of the substrate Fe (ξ ≈ 1.53 × 1016 cm−2) and the barrier layer oxide (Fe2O3) (ξ ≈ 6.89 × 1015 cm−2) for vacancy condensation upon the metal lattice or upon the cation sublattice of the film, respectively. This observation provides convincing evidence for the validity of the PDM for modeling passivity breakdown.

Passivity breakdown on carbon steel, which is the reference candidate material for fabricating high-level nuclear waste containers in Belgium, has been studied and the data are interpreted in terms of the point defect model (PDM). The near normal distribution in breakdown potential, measured in deaerated simulated concrete pore water solution (pH 12.5) at different chloride concentrations and temperatures are in satisfactory agreement with prediction of the PDM. An increase in temperature from 25°C to 85°C results in a decrease in localized corrosion resistance according to a linear relationship between the critical breakdown voltage, Eb , and log(chloride activity) for all chloride concentrations. The linear dependence of the passivity breakdown potential on the square root of potential scan rate (ν1/2), as predicted by the PDM, yields an estimate of the critical areal concentration of condensed cation vacancies at the metal/film interface (ξ14cm-2 at 85oC and 14cm-2 at 55oC ) that leads to the passivity breakdown. The experimental distributions in the breakdown potential for carbon steel at 55oC and 85oC are in satisfactory agreement with the relevant calculated distributions. Acknowledgment: The authors gratefully acknowledge the support of this work by ONDRAF-NIRAS of Belgium.

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