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Literatura académica sobre el tema "Chromace"

Autor: Grafiati

Publicado: 29 de marzo de 2025

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Artículos de revistas sobre el tema "Chromace"

Bastit-Kalinowska, Agnès. "Aquileienses clerici quasi chorus beatorum habentur (Hieronim, Kronika, rok 374). Przykład życia religijnego duchownych pod koniec IV wieku". Vox Patrum 70 (12 de diciembre de 2018): 205–15. http://dx.doi.org/10.31743/vp.3205.

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The end of the fourth century sees the emergence, in the West, of several experiences of monastic life in the city for the bishop and a part of his presbyterium (Eusèbe of Vercelli, Martin of Tours, Paulin of Nola, Augustin of Hippo). A similar attempt, around the priest Chromace of Aquileia (before his episcopate, and maybe even later), is documented by some testimonies of Jerome from Stridon and Rufin from Aquileia for the years 370s. These testimonies are the object of the present study.

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Escudero-Castejon, Lidia, Sergio Sanchez-Segado, Stephen Parirenyatwa y Animesh Jha. "Formation of Chromium-Containing Molten Salt Phase during Roasting of Chromite Ore with Sodium and Potassium Hydroxides". Journal for Manufacturing Science and Production 16, n.º 4 (1 de diciembre de 2016): 215–25. http://dx.doi.org/10.1515/jmsp-2016-0023.

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AbstractChromium has a wide range of applications including metals and alloys manufacturing, pigments, corrosion resistance coatings and leather tanning. The production of chromium chemicals is based on the oxidative alkali roasting of chromite ores, which leads to the formation of water-soluble alkali chromates. Previous investigations reported that when chromite is roasted with soda-ash, a molten salt containing chromium, which is mainly composed of sodium carbonate and sodium chromate (Na2CO3-Na2CrO4 binary mixture), forms under typical roasting conditions. The physical properties of the liquid phase, which are dependent on the temperature, charge and gangue compositions, play an important role on the oxidation reaction and may limit the chromate recovery by hindering the oxygen transport to the reaction interface. This investigation focuses on the alkali roasting of chromite ore at 1,000 oC using NaOH and KOH, followed by water leaching. The influence of the alkali ratio on the chromium extraction yield is analysed, and the results obtained with both hydroxides are compared. Sample characterisation and thermodynamic analysis, including phase diagrams, equilibrium calculations and computation of liquidus curves, are combined with the purpose of studying the formation of the molten salt phase under different roasting conditions and its effect on the final chromium recovery.

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Bockmair, Georg. "Non-Chromate Surface Protection for Aircraft Maintenance". Advanced Materials Research 38 (marzo de 2008): 7–13. http://dx.doi.org/10.4028/www.scientific.net/amr.38.7.

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While chromates as anti-corrosion pigments in primers and wash primers have disappeared in most industries, there are still quite a lot of chromated paints used in the aircraft industry. Intensive efforts to develop alternative pre-treatments to chromate conversion coatings and to chromic acid anodization have begun. The intention of this report is to give an overview of the state-of-the-art techniques about such pre-treatment/coating systems of aluminium for aircraft maintenance, which are in accordance with the latest environmental policies. The objective is to evaluate the combination of surface pre-treatment and paint as a whole.

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Ayinla, Kuranga I., Alafara A. Baba, Bankim C. Tripathy y Ranjan K. Dwari. "Production of Industrial-Grade Monoclinic Lead Chromate (PbCrO4) from Indigenous Chromite ore for Paint Pigment Utilization". Journal of Nepal Chemical Society 44, n.º 2 (6 de agosto de 2024): 101–9. http://dx.doi.org/10.3126/jncs.v44i2.68321.

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Decades of use have proven that lead chromate (PbCrO4) powder is an excellent paint pigment material. Unfortunately, practically this entire superb chromate compound used for decorative systems, protective systems, and mass dyeing of paper and polymer materials is conventionally made using inorganic synthetic chromium salts. In this study, we reported a promising simple, low-cost lead chromate production route derived from chromite ore from Nigeria. The Nigerian chromite ore was roasted in a 1:1 NaOH salt and then leached with water at 60°C. Lead nitrate was added to the leached liquor to further co-precipitate it. The resulting precipitate was then cleaned in ethanol and oven dried for ten hours at 80°C. The experimental results showed that lead ion concentration, temperature and flow rate have large influence on lead chromate precipitation, and the precipitation data fit a diffusion model. The activation energy of lead precipitation obtained was 4.76 kJ/mol, and the reaction order was 0.873 nearly one in relation to the concentration of lead ion. Additionally, XRD, FT-IR, and SEM/EDS comparative investigation of the properties established which favourable paint pigment performance similar to that of commercial industrial lead chromate powder in a range of all established physicochemical properties clarified the developing direction of research on lead chromate synthesis from Chromite leached liquor.

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Wunsch, Friederike M., Bernhard Wünsch, Freddy A. Bernal y Thomas J. Schmidt. "Quantitative Structure–Activity Relationships of Natural-Product-Inspired, Aminoalkyl-Substituted 1-Benzopyrans as Novel Antiplasmodial Agents". Molecules 26, n.º 17 (30 de agosto de 2021): 5249. http://dx.doi.org/10.3390/molecules26175249.

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On the basis of the finding that various aminoalkyl-substituted chromene and chromane derivatives possess strong and highly selective in vitro bioactivity against Plasmodium falciparum, the pathogen responsible for tropical malaria, we performed a structure–activity relationship study for such compounds. With structures and activity data of 52 congeneric compounds from our recent studies, we performed a three-dimensional quantitative structure–activity relationship (3D-QSAR) study using the comparative molecular field analysis (CoMFA) approach as implemented in the Open3DQSAR software. The resulting model displayed excellent internal and good external predictive power as well as good robustness. Besides insights into the molecular interactions and structural features influencing the antiplasmodial activity, this model now provides the possibility to predict the activity of further untested compounds to guide our further synthetic efforts to develop even more potent antiplasmodial chromenes/chromanes.

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Equeenuddin, Sk Md y B. C. Raymahashay. "Retention of Anionic Pollutants by Overburden Material at Chromite Mines: An Experimental Investigation". Asian Journal of Water, Environment and Pollution 5, n.º 4 (enero de 2008): 109–13. http://dx.doi.org/10.3233/ajw-2008-5_4_12.

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The goethite-rich overburden material at chromite mines is an efficient sink for the chromate anion. Leaching experiments using a saline solution showed that the material at the Sukinda mine of Orissa had retained a higher amount of chromate compared with the material at the nearby Boula mine. This difference can be attributed to the mineralogy at the two sites. For example, the proportion of poorly crystalline goethite is higher in the Sukinda material compared with Boula. Experiments on further adsorption of arsenate and phosphate indicated that the Boula sample had higher uptake capacity for both anions. This is obviously because the Sukinda sample had initially adsorbed more chromate. These results can be useful in evaluating natural attenuation of fertilizer-derived pollutants in the agricultural land near chromite mines.

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Cagide, F., T. Silva, J. Reis, A. Gaspar, F. Borges, L. R. Gomes y J. N. Low. "Discovery of two new classes of potent monoamine oxidase-B inhibitors by tricky chemistry". Chemical Communications 51, n.º 14 (2015): 2832–35. http://dx.doi.org/10.1039/c4cc08798d.

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Lemarié, Joseph. "Le sermon 34 de Chromace d'Aquilée pour I'Épiphanie. Nouvelle attestation dans I'homéliaire carolingien du Pseudo-Bède". Sacris Erudiri 33 (enero de 1992): 121–24. http://dx.doi.org/10.1484/j.se.2.303777.

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Tapia, I., V. Alcázar y J. R. Morán. "Synthesis of chromanes using pyruvic acid dimethylhydrazone dianion". Canadian Journal of Chemistry 68, n.º 12 (1 de diciembre de 1990): 2190–91. http://dx.doi.org/10.1139/v90-335.

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Petit, François, Henri Debontride, Michel Lenglet, Gérard Juhel y Didier Verchere. "Contribution of Spectrometric Methods to the Study of the Constituents of Chromating Layers". Applied Spectroscopy 49, n.º 2 (febrero de 1995): 207–10. http://dx.doi.org/10.1366/0003702953963733.

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The amorphous constituents of a chromating layer may be defined by the simultaneous use of diffuse reflection spectrometry in the ultraviolet and visible, and of Fourier transform infrared spectrometry. The PO4 group is characterized in the infrared reflection spectrum by bands located near 1070, 1030, and 900 cm−1 for chromium phosphate. The CrO4 group induces bands at 960, 860, and 820 cm−1 for zinc chromate and at about 980, 950, and 860 cm−1 for chromium chromates. The ligandmetal charge transfer bands (LMCT) characteristic of the chromates are situated in the region 3.35 to 4.20 eV. The study of the thermal behavior of chromium phosphate CrPO4 and zinc chromate ZnCrO4 shows that these compounds are stable up to 300°C. Complex chromates of Cr(III) may be observed in the range 150 to 300°C. These analytical data show the contribution of these methods which, used in the reflection mode, are demonstrably the best suited to the analysis of chromating layers on coated steel, of which the primary constituents are chromium phosphate and complex Cr(III) chromates. These results allow the interpretation of the thermal behavior of chromating layers.

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Tesis sobre el tema "Chromace"

Del, Pianta Dimitri. "Détermination des paramètres physcio chimiques régissant l’électrodéposition d’une couche de chrome métallique à partir d’une solution de chrome trivalent". Thesis, Pau, 2017. http://www.theses.fr/2017PAUU3035/document.

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De par leurs propriétés mécaniques et anti-corrosion élevées, les revêtements métalliques de chrome sont utilisés dans de nombreux domaines tels que l’aéronautique, l’automobile, le ferroviaire, la défense,… Aujourd’hui le chromage dur industriel, réalisé à partir de chrome hexavalent, est fortement menacé par la directive européenne REACH qui prévoit l’interdiction d’utilisation de sels de chrome VI (classé CMR) à l’horizon 2017. Dans ce contexte le projet HCTC (Hard Chromium by Trivalent Chromium) regroupe 16 partenaires industriels et 2 partenaires académiques sous la coordination de l’Institut de Recherche Technologique Matériaux, Métallurgie, Procédés (IRT M2P) afin de développer une alternative à base de sel de chrome trivalent. Le développement d’un procédé de substitution à partir de sels de chrome trivalent nécessite de répondre aux interrogations liées notamment à la difficulté de réduire les ions Cr3+ formant en solution aqueuse un complexe hexa-aqua [Cr(H2O)6]3+ très stable et difficilement réductible. Afin de faciliter la réduction, l’ensemble des travaux recensés dans la littérature prône l’utilisation d’un agent complexant organique afin d’augmenter l’accessibilité du chrome. Une première partie de ce travail de thèse a été de caractériser les dépôts de chrome métallique réalisés à partir de la formulation de chrome III (EXDBA 1318) afin de mettre en évidence l’influence des paramètres de chromage (température du bain de traitement, densité de courant,…) sur les propriétés physico-chimiques des dépôts (Morphologie, cristallinité, composition chimique). Les résultats ont montré que la diminution de fissures tranversantes est généralement accompagnée d’une augmentation du taux de carbure de chrome qui dégrade l’état cristallin. La compréhension et l’optimisation du procédé a permis la réalisation de dépôts avec des propriétés physico-chimiques permettant de lancer les premiers essaies industriels dont les premiers retours sont très encourageants pour certaines applications (essentiellement automobile).Dans une deuxième partie plus fondamentale, des analyses par HPLC-ICP/AES ont mis en évidence la complexation du chrome par différents agents complexant. Les résultats obtenus ont montré que la complexation étaient d’autant plus importante que le pH est haut (pH=5) et le rapport molaire [Cr]/[Cplx] faible (1/10). Les mécanismes de réduction associés aux taux de complexation ont ensuite été déterminés par des mesures de voltammétrie cyclique en utilisant des électrodes sérigraphiées modifiées par de l’or. Les voltammogrammes obtenus montrent que la complexation du chrome par un agent complexant permet de passer d’un mécanisme de réduction en deux étape (Cr3+  Cr2+  Cr) en une seule (Cr3+  Cr).Une dernière partie du travail a été de définir l’influence de la chimie sur bain (pH et rapport molaire [Cr]/[Cplx]) sur les propriétés physico-chimiques des dépôts. Les résultats obtenus ont montré que pour des solutions faiblement complexées il est préférable de travailler à des pH bas et d’appliquer de faibles densités de courant (<15A/dm²) tandis qu’une augmentation du taux de complexation du chrome par l’agent complexant nécessite d’appliquer des densités de courant plus fortes. Ce travail a aussi permis de montrer l’existence d’une zone de pH optimale pour un rapport molaire [Cr]/[Cplx] donnée. L’existence de cette zone de pH révèle l’existence d’un domaine d’équilibre en solution, favorable à la réduction du chrome. L’ensemble de ces travaux plus fondamentaux ont permis d’améliorer les connaissances sur le procédé de chromage à partir d’un sel de chrome trivalent et ainsi de réfléchir à une nouvelle formulation pour des applications plus critiques où la solution actuelle a pu montrer quelques limites
Due to their high mechanical and anti-corrosion properties, chromium metal coatings are used in many fields such as aeronautics, automotive, railway, defense, etc. Today industrial hard chromium coating, made from of hexavalent chromium, is strongly threatened by the European REACH Directive, which provides for the prohibition of the use of chromium VI salts (classified as CMR) by 2017. In this context, the HCTC project (Hard Chromium by Trivalent Chromium) groups together 16 industrial partners and 2 academic partners under the coordination of the Institute for Materials, Metallurgy and Process Technology Research (IRT M2P) to develop an alternative based on trivalent chromium salt. The development of a substitution process from trivalent chromium salts requires answering the questions related in particular to the difficulty of reducing the Cr3+ ions forming in aqueous solution a very stable hexa-aqua [Cr(H2O)6]3+ complex and hardly reducible. In order to facilitate the reduction, all the works listed in the literature advocate the use of an organic complexing agent in order to increase the accessibility of chromium.A first part of this thesis work was to characterize the chromium metal deposits made from the chromium III formulation (EXDBA 1318) in order to highlight the influence of chromium parameters (bath temperature, density of current, ...) on physico-chemicals properties of the deposits (Morphology, crystallinity, chemical composition). The results showed that the decrease of transverse cracks is generally accompanied by an increase in chromium carbide which degrades the crystalline state. The understanding and the optimization of the process allowed the realization of deposits with physico-chemical properties allowing to launch the first industrial tests whose first returns are very encouraging for certain applications (mainly automobile).In a second, more fundamental part, HPLC-ICP / AES analyzes have demonstrated the complexation of chromium by different complexing agents. The results obtained showed that the complexation was all the more important that the pH is high (pH = 5) and the molar ratio [Cr] / [Cplx] low (1/10). Reduction mechanisms associated with complexation rates were then determined by cyclic voltammetry measurements using gold-modified screen-printed electrodes. The voltammograms obtained show that the complexation of chromium by a complexing agent makes it possible to go from a reduction mechanism in two steps (Cr3+  Cr2+  Cr) to a single one (Cr3+  Cr).A final part of the work was to define the influence of bath chemistry (pH and [Cr]/[Cplx] molar ratio) on the physico-chemical properties of coatings. The results obtained showed that for weakly complexed solutions it is preferable to work at low pH and to apply low current densities (<15A / dm²) while an increase in the chromium complexation rate by the complexing agent requires the application of higher current densities. This work also showed the existence of an optimal pH zone for a given [Cr]/[Cplx] molar ratio. The existence of this zone of pH reveals the existence of a balance domain in solution, favorable to the reduction of chromium. All of these more fundamental works have made it possible to improve the knowledge on the chromium plating process from a trivalent chromium salt and thus to think about a new formulation for more critical applications where the current solution has been able to show some limits

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Neizel, Bryson Wade. "Alteration of chrome-to-iron ratio in chromite ore by chlorination / Bryson Wade Neizel". Thesis, North-West University, 2010. http://hdl.handle.net/10394/4313.

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The industrial importance of the chromium industry to South Africa is emphasised by the fact that it is considered the largest chromite (chromium ore) and ferrochrome (chrome-iron alloy) producing country in the world. Although South Africa holds three quarters of the world's chromite ore reserves, the chrome-to-iron (Cr-to-Fe) ratio of the local chromite ores is relatively low (1.47 to 1.55), compared to other deposits in the world (2.6 to 3.5). Additionally, iron is more readily reduced than chromium. The combination of these two factors implies that ferrochrome produced from South African chromite ore contains 47-53% chromium. Current pricing practises in the world ferrochrome industry dictate that ferrochrome producers are only paid for the chromium content in the ferrochrome, which implies that South African ferrochrome producers export a large percentage of their product without any financial benefit. Research to improve the Cr-to-Fe ratio is therefore essential to support sustainability of the local ferrochrome industry. Conventional beneficiation methods such as gravity concentration, magnetic separation and floatation are unlikely to increase the Cr-to-Fe ratio, since both iron and chromium are part of the same mineral phase, i.e. the spinel, which requires structural dissociation. It has been proven on laboratory scale that high temperature carbochlorination (CO and Clz atmosphere) can be used to selectively remove iron from chromite. However, such methods are unlikely to be implemented on an industrial scale due to health, environmental and cost considerations. In light of this, an alternative approach to chromite chlorination, avoiding the use of chlorine and other toxic gasses, was investigated during this study. Since it was found that NaCI addition significantly improved the effectiveness of carbochlorination of chromite, the effect of adding only NaCI during high temperature treatment of chromite was investigated. The material utilised during this investigation consisted of local chromite, anthracite (source of carbon) and attapulgite clay (serving as a binder). These materials were mixed in a ratio and subsequently milled to 0 90 = 75fJm to represent materials and specifications similar to those used during pelletisation of the chromite in the pre-reduction ferrochrome production process. This mixture could also be used to generate a partially reducing atmosphere (CO rich) during high temperature treatment, which was similar to the reaction conditions utilised during carbochlorination. The abovementioned milled mixture was pelletised into cylindrical pellets with a die set and a hydraulic press. This experimental investigation was based on a mono-variance procedure, in that the four different variables investigated, i.e. maximum pellet treatment temperature, exposure time, wt% NaCI addition to the pellets and the atmosphere the pellets were exposed to, were varied one at a time during experimentation. After each alteration of the afore-mentioned variables, the Cr-to-Fe ratios, together with other parameters, were measured. Analyses undertaken included Scanning Electron Microscopy, with Energy-Dispersive X-ray Spectroscopy (SEM-EDS), Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and cured breaking strength. Although this investigation did not focus on the cured breaking strength of the pellets, it is a very important industrial parameter and was therefore measured. Results indicated that the addition of NaCI had a definite effect. In both oxidising and partially reducing atmospheres the cured breaking strength of the cured pellets increased up to 800°C exposure, whereafter it decreased. This was attributed to melting of NaCI at 801 °C. In the oxidising atmosphere, the cured breaking strength increased again at temperatures higher than 1 000°C, due to the formation of a thin oxldised layer on the outside of the pellets, which could be confirmed by SEM analysis. Fine, metallic-like crystals were noticed inside and on the lids of crucibles in which pellets containing NaCI as an additive were cured at temperatures of 900°C or higher. SEM-EDS analysis and weight-ratio calculations revealed that these crystals were pure FeO. This indicated that some iron might have been liberated from the chromite spinel matrix. However, ICP-OES analyses revealed that Cr-to-Fe ratios did not change significantly under any of the experimental conditions (NaCI addition 5wt% to 15wt%, curing between 500'C and 1200'C, and oxidative/partially reducing atmospheres). The observed FeO crystals did not make any meaningful difference to the Crto- Fe ratio of the chromite, but was of great academic interest as iron was extracted from the chromite spinel. This indicated that it is not only the formation of low melting point species, such as those proposed in previous mechanistic studies of carbochlorination of chromite, but that molten NaCI alone could also initiate the extraction of iron out of chromite. According to the knowledge of the author, this is the first report of its nature in open literature. SEM and SEM-EDS analyses also proved that the addition of NaCI to the chromite/carbon/clay mixtures enhanced the rate of chromite pre-reduction. This finding was in agreement with earlier literature reports. In conclusion, it can be stated that the addition of NaCI alone cannot alter the Cr-to-Fe ratio of chromite during high temperature treatment. NaCI addition did, however, have an effect on other important parameters i.e. initiation of iron removal, cured breaking strength and the rate of chromite pre-reduction. From the results and experience gained in this study, certain recommendations with regard to possible future studies could also be made. This included investigating i) other single component additives to possibly alter the Cr-to-Fe ratio during high temperature treatment, ii) the effect of industrially relevant additives such as CaO/CaC03, Mg03 and SiOz on the rate of chromite pre-reduction and iii) the effect of different clays (e.g. attapulgite, bentonite, etc.) on the rate of chromite pre-reduction.
Thesis (M.Sc. (Chemistry))--North-West University, Potchefstroom Campus, 2010.

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Parsa, Yohan. "Oxydation thermique du chrome pur en atmosphère contrôlée : propriétés semiconductrices et structurales de la chromine". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI081/document.

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La durabilité chimique des alliages métalliques résulte notamment de la nature des défauts ponctuels assurant le transport au travers du film d’oxydation formé en surface. L'élaboration de couches d'oxyde modèles par oxydation thermique en pression contrôlée et ALD (Atomic Layer Deposition) et l'étude de leurs propriétés semi conductrices (conditionnées par la nature des défauts ponctuels) devrait permettre une meilleure compréhension des mécanismes de formation de ces couches d'oxyde
The chemical durability of the metal alloy results in particular from the nature of point defects providing transport through the oxidation film formed on the surface. Models oxide layers, grown by thermal oxidation and Alomic Layer Deposition, will be studied by photoelectrochemistry. This will provide us information about the semiconductive properties of the oxide, determined by the point defect in the oxide layer, and should allow us a better understanding of the formation mechanism of these oxide

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Rolet, Jason. "Influence de la forme de l'onde de polarisation sur la microstructure et les propriétés de revêtements électrolytiques élaborés à base de chrome trivalent". Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCD010.

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Ce travail de thèse s’inscrit dans un projet de grande envergure piloté par l’IRT M2P, intitulé « Hard Chrome by Trivalent Chromium » qui regroupe 15 partenaires industriels et 2 partenaires académiques. L’objectif principal est de substituer les composés du chrome hexavalent par des électrolytes à base de chrome trivalent dans les procédés de chromage « dur », en réponse à l’application du règlement européen REACH en septembre 2017, même si des demandes d’autorisations temporaires sont en cours. Dans le cadre de cette thèse, des études électrochimiques ont été réalisées sur des bains commercial et synthétique. Celles-ci ont conduit au choix d’un matériau jouant le rôle d’anode, à une meilleure compréhension des mécanismes mis en jeu et de ce fait à une optimisation des conditions d’utilisation du bain commercial. D’autre part, une étude approfondie des courbes transitoires permet de mieux appréhender le comportement des électrolytes de chrome trivalent vis-à-vis des courants pulsés. Ainsi, un plan d’expérience sur les paramètres des pulses avec pour sortie de multiples caractérisations des dépôts de chrome montre que les courants pulsés influent sur plusieurs propriétés telles que : la teneur en carbone, la structure cristalline, la microdureté, la morphologie de surface et la microfissuration. Grâce au traitement des données issues du plan d’expériences, l’optimisation des paramètres de polarisation aboutit à l’élaboration de séquences de pulses optimisées. L’utilisation de celles-ci, employées seules ou en combinaison avec d’autres séquences de pulses issues également du plan d’expériences, aboutit à l’obtention de dépôts de chrome trivalent dont les propriétés sont modulables en fonction des paramètres procédés. Dans l’optique de la mise en place d’une nouvelle stratégie de choix des paramètres de l’impulsion anodique, un dispositif permettant la mesure du pH local en fonction des séquences et à proximité immédiate de la surface a été élaboré. Les premières tendances confirment les modes d’action des courants pulsés, et les choix qui ont été faits pour l’optimisation
This thesis work is part of an ambitious project handled by IRT M2P, named “Hard Chrome by Trivalent Chromium” which gathers 15 industrials partners but also 2 academic partners. The main objective is to substitute the hexavalent chromium compounds in hard chromium electroplating process before there ban by European instances (REACH, ECHA) in September 2017, excepted for those authorized. As part of this thesis, electrochemical studies were realized on commercial and synthetic baths. Thanks to this studies, a material has been chosen to act as an anode for the making of the trivalent chromium coatings ; furthermore, the utilization conditions of the commercial bath has been optimized. Moreover, another study based on transient curves allows a better comprehension of the behaviour of the trivalent chromium electrolytes regarding pulsed current. This work permitted the elaboration of pulse sequences in the form of an experimental design. The realization and characterization of trivalent chromium coatings as a part of the experimental design show that pulsed current have an effect on several properties of the coatings such as carbon content, crystalline structure, microhardness, surface morphologies an microcracking. Thanks to the analyses of the results from the experimental design, an optimization of pulsed current has been made to obtain optimized pulse sequences. The utilization of those pulse sequences, used alone or combine with some pulse sequences of the experimental design lead to the elaboration of trivalent chromium coatings which properties are adjustables depending on the set parameters of the process. To further optimize the properties of the coatings, the basis of an analysis tool based on local pH measurements are developed; this analysis tool must make it possible to select the most interesting pulse sequences for the realization of trivalent chromium coatings

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Presley, Christopher Charles. "Isolation, Structure Elucidation, and Total Synthesis of Biologically Active Natural Products from Plants". Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/79978.

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As a part of the continuing search for bioactive compounds with the Madagascar International Cooperative Biodiversity Group (ICBG), and in collaboration with the Natural Products Discovery Institute of the Institute for Hepatitis and Virus Research (IHVR), thirteen plant extracts were investigated for antiplasmodial activity, thirteen plant extracts were investigated for antiproliferative activity, and one extract was investigated for inhibitors of the shikimate pathway in Plasmodium falciparum. Bioassay-guided fractionation of the extracts led to the identification of nineteen compounds with both antiplasmodial and antiproliferative activity, and thirteen compounds with only antiproliferative activity. Thirteen of these compounds (2.1 – 2.9, 3.3, 3.4, 4.5, and 5.1) were previously unknown. In addition total synthesis was used to confirm the structure of one new compound (4.5) and two other new natural-product like compounds (4.6 and 4.7) were also synthesized and investigated for antiplasmodial activity.
Ph. D.

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Tissot, Louis-Jean. "L'Ouvrage incomplet sur Matthieu (Opus imperfectum in Matthaeum) et les commentaires en latin sur l'évangile de Matthieu de l'Antiquité. Comparaison exégétique et stylistique ciblée sur la partie A (Mt. 1-8)". Electronic Thesis or Diss., Sorbonne université, 2024. http://www.theses.fr/2024SORUL158.

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S'inscrivant dans le projet d'édition critique de l'Ouvrage incomplet sur Matthieu (Opus imperfectum in Matthaeum, OIM), la présente thèse analyse les liens entre ce commentaire anonyme sur l'évangile de Matthieu, provenant d'un milieu subordinationiste riminien (i.e. « homéen »), et d'autres ouvrages exégétiques latins sur le même évangile. Après avoir rappelé, dans un état de la recherche, les principales caractéristiques du corpus pris en compte, nous avons procédé à une comparaison exégétique suivie portant sur la section Mt 1-8, correspondant à la première partie de l'OIM, avec les commentaires sur Matthieu de Fortunatien d'Aquilée et d'Hilaire de Poitiers (milieu IVe siècle), ceux de Jérôme et Chromace d'Aquilée (fin IVe siècle), et les textes d'un auteur latin anonyme de la fin de l'Antiquité surnommé le pseudo-Origène. Cette étude s'est doublée d'une comparaison stylistique sur quelques aspects (appellations du Christ, vocabulaire exégétique, marques de personne), faisant ressortir la profonde originalité de l'OIM à cet égard. Le bilan de cette double comparaison confirme l'influence profonde du Commentaire sur Matthieu d'Origène sur l'OIM, ce qui rapproche l'auteur anonyme de Jérôme. De plus, notre étude met en évidence pour la première fois son utilisation du Commentaire sur Matthieu de Chromace d'Aquilée. Enfin, les résultats de la comparaison stylistique, assortis d'une analyse théologique des positions du traducteur, tendent à confirmer que c'est bien à l'auteur de l'OIM que nous devons l'ancienne traduction latine du Commentaire sur Matthieu d'Origène
As part of the critical edition project of the Incomplete Work on Matthew (Opus imperfectum in Matthaeum, OIM), the present thesis analyzes the links between this anonymous commentary on the Gospel of Matthew, coming from a Riminian subordinationist environment (i.e. “Homean”), and other Latin exegetical works on the same gospel. After recalling, in a state of research, the main characteristics of the corpus taken into account, we carried out a continued exegetical comparison relating to the section Mt 1-8, corresponding to the first part of the OIM, with the fragments remains of the commentary on Matthew by Origen (3rd century), the commentaries on Matthew by Fortunatian of Aquileia and Hilary of Poitiers (mid-4th century), those of Jerome and Chromatius of Aquileia (late 4th century), and the texts by an anonymous Latin author from late Antiquity known as pseudo-Origen. This study was accompanied by a stylistic comparison on certain aspects (appellations of Christ, exegetical vocabulary, personal marks), highlighting the profound originality of the OIM in this regard. The results of this double comparison confirm the deep link of the OIM with Origen's Commentary on Matthew, an influence that the anonymous author shares with Jerome. Furthermore, our study shows for the first time the use in the OIM of the Commentary on Matthew by Chromatius of Aquileia. Finally, the results of the stylistic comparison, accompanied by a theological analysis of the translator's positions, tend to confirm that it is indeed to the author of the OIM that we owe the ancient Latin translation of the Commentary on Matthew of Origen

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Li, Longfei. "Study of Corrosion and Corrosion Inhibition of Chromate and Chromate-Free Primers". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1344896405.

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Adjei, Mensah Evelyne. "Dissémination environnementale du chrome en contexte minier : études physique, chimique et isotopique". Electronic Thesis or Diss., Université Paris Cité, 2022. http://www.theses.fr/2022UNIP7060.

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L'étude du cycle des métaux dans l'environnement et de l'impact de l'activité anthropique constitue un enjeu environnemental et sanitaire important. Les sites ultramafiques sont caractérisés par leur faible teneur en nutriments (N, P et K), leur minéralogie dominée par les oxydes de Fe et leur enrichissement naturel en métaux tels que Cr, Fe et Ni. Ces systèmes ultramafiques sont des sites de choix pour les compagnies minières. Les activités minières génèrent plusieurs tonnes de déchets miniers tels que les résidus miniers, les minerais peu concentrés et les terrils. Ces déchets miniers peuvent être à l'origine de pollution des eaux et des sols. Parmi les métaux naturellement présents dans les sites ultramafiques, le chrome est exploité sous forme de minerai de chromite. Le chrome existe sous deux états d'oxydation dans l'environnement. Le chrome trivalent (Cr(III)) est un nutriment ayant un rôle important dans la régulation de la glycémie tandis que le chrome hexavalent (Cr(VI)) est toxique et carcinogène. L'utilisation de la signature isotopique du Cr a été proposée en tant que traceur du Cr(VI) dans les eaux souterraines et pour évaluer les sources de contamination. A ce jour, il n'existe pas d'étude à l'échelle d'une vallée en système ultramafique qui combine spéciation et signature isotopique afin de contraindre les sources de pollution au Cr en contexte minier. Mon travail de thèse a donc pour objectif de déterminer, avec un jeu de données très complet (70 eaux, 2 chromites, 2 terrils, 1 minerai concentré, 15 sols, 5 sédiments), les sources de Cr et les processus biogéochimiques à l’œuvre dans les systèmes environnementaux, tels que les sols impactés par l'activité minière d'extraction du chrome. Le site choisi pour cette étude est la vallée de Sukinda (Inde), classé comme étant le 4ème site le plus pollué au monde en 2007. Les conséquences environnementales, sanitaires et sociales liées à un tel classement confèrent un intérêt tout particulier à ce site pour l'étude des sources de pollution du Cr et des processus biogéochimiques. Ma thèse s'articule autour de deux questions scientifiques déclinées en question spécifiques : A. Dans quelle mesure l'activité minière modifie-t-elle la mobilité, la disponibilité, la spéciation et la signature isotopique du chrome ? Peut-on tracer les sources de Cr et déterminer les processus biogéochimiques influençant la biodisponibilité du chrome dans la vallée de Sukinda grâce à la signature isotopique du chrome ? B. Quel est le devenir du Cr lorsqu'il est relargué des déchets miniers ? Quels sont les impacts des terrils sur les sols de rizières environnants ?
Metals cycle in the environment and the impact of anthropic activities are major environmental concerns. Ultramafic sites are characterised by their poor content in nutrients (N, P and K), their mineralogy dominated by Fe oxides and their natural enrichment in metals such as Cr, Fe and Ni. Thus, these systems are sites of choice for the mining companies. Mining activities produce huge amounts of wastes such as overburden, low grade ores and tailings. These wastes can be the source of water and soil pollution. Among the metals naturally present in ultramafic systems, chromium is mined as chromite ore. Chromium is stable in the environment under two oxidation states. Trivalent chromium (Cr(III)) is a nutrient which plays an important role in glycemia control while hexavalent chromium (Cr(VI)) is toxic and carcinogenic. The use of Cr isotopic signature has been proposed in order to trace Cr(VI) in groundwater and assess the source of contamination. To this day, there is no study at the scale of a catchment basin which combines Cr speciation and isotopic signature in order to determine Cr sources of pollution in a mining context. The goal of this study is to determine, with a complete dataset (70 water samples, 2 chromites, 2 tailings, 1 concentrated ore, 15 paddy soils and 5 sediments), what are the sources of Cr and which biogeochemical processes are occurring in environmental settings such as soils impacted by chromite mining. The study site is Sukinda valley (India), fourth site worst polluted in the world in 2007. Environmental, sanitary and social consequences link to such a site confer a particular interest to this valley in the study of Cr sources of pollution and biogeochemical processes involved. The two main problematics detailed in this manuscript are: A. To what extent do mining activities modify Cr mobility, availability, speciation and isotopic signature? Can we trace Cr sources thanks to its isotopic signature? Can we trace the biogeochemical processes involved in Cr bioavailability thanks to Cr isotopic signature in Sukinda valley (India)? B. What is the fate of Cr once released from mining wastes? What are tailings impacts on the surrounding paddy soils?

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Abdelouhab, Sandra. "Détermination de grandeurs physico-chimiques dans les verres fondus - Relation avec le comportement en corrosion du chrome et d'alliages chromine-formeurs". Nancy 1, 2005. http://www.theses.fr/2005NAN10155.

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Ce travail de thèse a eu pour buts : - d'édifier une échelle de basicité dans les milieux verres fondus. Une cellule électrochimique permettant la détermination in situ des activités en Na2O et appelée méthode des piles de concentrations a été développée. Cette méthode a permis de mesurer la basicité de verres de compositions simplifiées et industrielles pour les comparer entre eux et critiquer les modèles de basicité existants. - de déterminer la solubilité de Cr2O3 dans les fontes de verres et montrer que la teneur en chrome dissous dépend de la température d'expérience, de la basicité du verre, de sa structure et de la pO2 dans l'atmosphère environnante. L'oxyde de chrome est un oxyde amphotère dans ces milieux. - d'étudier l'interaction entre le chrome métal et les fontes des verres Na2O-xSiO2 pour mettre en évidence l'influence de la basicité des verres, de la température et de la pression partielle en oxygène sur les cinétiques et le mécanisme de corrosion du chrome
The aims of this work were : - To build a basicity scale in glass melts. A specific electrochemical cell was designed to measure in situ the Na2O activities. This method allowed the basicity measurement of several silicate melts (of with simplified and industrial compositions) to compare these glasses between each other and to criticise the existing glass basicity models. - To determine the Cr2O3 solubility in glass melts. The chromium content that is dissolved in the glass depends on experimental temperature, glass basicity, melt structure and pO2 in the atmosphere surrounding the glass. Cr2O3 exhibits an amphoteric behaviour in glass melts. -To study the interaction between Cr metal and Na2O-xSiO2 glass melts in order to determine the influence of glass basicity, experimental temperature and partial pO2 on chromium corrosion kinetics and mechanism

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Woodbridge, Nesta. "Mechanistic studies relevant to chromate toxicity". Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267077.

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Libros sobre el tema "Chromace"

Great Britain. Health and Safety Executive., ed. Chromate primer paints. Sudbury: HSE Books, 1999.

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Silk, M. H. World chromite resources and ferrochromium production. Randburg: Council for Mineral Technology, 1988.

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Leinonen, Ossi. Use of chromite microstructure image analysis to estimate concentration characteristics in the Kemi Chrome Ore. Oulu: Oulun yliopisto, 1998.

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Nader, George. Chrome. Boston, Mass: Alyson, 1987.

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Barthelme, Frederick. Chroma. London: Penguin, 1988.

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Green, Paula. Chrome. Auckland: University of Auckland Press, 2000.

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Green, Paula. Chrome. Auckland, N.Z: Auckland University Press, 2000.

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Nader, George. Chrome. Los Angeles: Alyson Publications, 1995.

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Nader, George. Chrome. Boston: Alyson Publications, 1987.

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Julian, Cox y High Museum of Art, eds. Chroma. Portland, Or: Nazraeli Press, 2011.

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Capítulos de libros sobre el tema "Chromace"

Auwers, Jean-Marie. "Chromace d’Aquilée et le texte biblique". En Chromatius of Aquileia and His Age, 343–59. Turnhout: Brepols Publishers, 2011. http://dx.doi.org/10.1484/m.ipm-eb.1.100875.

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Gounelle, Rémi. "Chromace d’Aquilée et la passion du Christ". En Chromatius of Aquileia and His Age, 295–320. Turnhout: Brepols Publishers, 2011. http://dx.doi.org/10.1484/m.ipm-eb.1.100872.

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Sotinel, Claire. "L’évêque chrétien devant la diversité religieuse de la cité: Chromace et Aquilée". En Chromatius of Aquileia and His Age, 163–76. Turnhout: Brepols Publishers, 2011. http://dx.doi.org/10.1484/m.ipm-eb.1.100865.

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Bastit-Kalinowska, Agnès. "Les Tractatus in Matthaeum de Chromace et leur lecture de l’évangile de «Matthieu»". En Chromatius of Aquileia and His Age, 425–67. Turnhout: Brepols Publishers, 2011. http://dx.doi.org/10.1484/m.ipm-eb.1.100877.

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Naumowicz, Józef. "Les symboles des quatre Évangélistes chez Chromace d’Aquilée et chez les autres auteurs patristiques". En Chromatius of Aquileia and His Age, 469–84. Turnhout: Brepols Publishers, 2011. http://dx.doi.org/10.1484/m.ipm-eb.1.100878.

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Sarkar, Ritwik. "Chromite and MgO–Cr2O3 Refractories (Chrome–Mag and Mag–Chrome)". En Refractory Technology, 169–79. 2^a ed. Boca Raton: CRC Press, 2023. http://dx.doi.org/10.1201/9781003227854-10.

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Gooch, Jan W. "Barium Chromate". En Encyclopedic Dictionary of Polymers, 66. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_1060.

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Gooch, Jan W. "Strontium Chromate". En Encyclopedic Dictionary of Polymers, 707. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_11322.

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Gooch, Jan W. "Zinc Chromate". En Encyclopedic Dictionary of Polymers, 824. New York, NY: Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_12993.

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Duval, Yves-Marie. "Les relations doctrinales entre Milan et Aquilée durant la seconde moitié du IVe Siècle Chromace d'Aquilée et Ambroise de Milan". En L'extirpation de l'Arianisme en Italie du Nord et en Occident, V—171—V—234. London: Routledge, 2024. http://dx.doi.org/10.4324/9781003555063-5.

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Actas de conferencias sobre el tema "Chromace"

Kislov, E. V., V. S. Kamenetsky y E. A. Belousova. "CHROMITITES OF THE MAIN SARANOVSKOYE FIELD, PERM TERRITORY: COMPOSITION AND GENESIS". En Проблемы минералогии, петрографии и металлогении. Научные чтения памяти П. Н. Чирвинского. Пермский государственный национальный исследовательский университет, 2021. http://dx.doi.org/10.17072/chirvinsky.2021.95.

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The chromitites mineral composition from the Central ore body of the Main Saranovskoye deposit has been studied. Development of chromite grains in silicate interstices; constancy of its composition, idiomorphism; increased chromium content of small and periphery of large chromite grains; absence of corrosion, substitution with chrome magnetite or chlorite; xenomorphic high chromium chromite; association with chromium-containing minerals and minerals of hydrothermal origin; joint growth of chromite with uvarovite; predominance of minerals with Na and H2O in inclusions in chromite; inclusions of idiomorphic grains and chlorite laths, massicot crystals; the inclusion of laurite with a crystallographically faceted inclusion of chalcocite, chromite in the diabase skarn indicates that chromite was not a source of chromium for other minerals, but was formed together with hydrothermal minerals in the course of a single process. This is also evidenced by the composition of apatite: a high Y content and a negative Eu anomaly.

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Shalabi, M., N. El-Hussiny, S. El-Afifi, N. El-Ebiary y F. Zaher. "Kinetics of formation of sodium chromate from El-Baramiya chromite ore concentrate with soda ash pellets". En The 8th International Mineral Processing Symposium. Taylor & Francis Group, 6000 Broken Sound Parkway NW, Suite 300, Boca Raton, FL 33487-2742: CRC Press, 2017. http://dx.doi.org/10.4324/9780203747117-105.

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Brown, R., P. K. Depa y W. C. Tucker. "A Comparison Between A Chromate and A Non Chromate Surface". En Advanced Marine Materials: Technology & Application. RINA, 2003. http://dx.doi.org/10.3940/rina.amm.2003.12.

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ЗИНЧУК Н, Н. "О ПОИСКОВОЙ РОЛИ ПЕРВИЧНЫХ МИНЕРАЛОВ КИМБЕРЛИТОВ". En ГЕОЛОГИЯ И МИНЕРАЛЬНО-СЫРЬЕВЫЕ РЕСУРСЫ СЕВЕРО-ВОСТОКА РОССИИ 2024, 86–94. Crossref, 2024. http://dx.doi.org/10.53954/9785604990100_86.

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Brief information is provided on the results of research of diamonds and other primary minerals of kimberlites (pyrope, chrome-diopside, chrome-spinellid, clinopyroxene, picroilmenite and chromite) from diatremes of the Siberian diamondiferous province (SDP), which allowed defining of their typomorphic features. Distinguishing of four types of diamonds' primary sources (crystals from rich kimberlite bodies and with poor diamondiferousness, of unknown genesis and impact genesis) enabled working out criteria of regional and local zoning of perspective territories where primary and placer productivity were discovered. The obtained data allowed dividing SDP into four sub-provinces: Central-Siberian (central part of the platform) with prevalence of type I primary source; Lena-Anabar (north-east of the region) with prevalence of type III primary sources of unknown genesis; Tungusskaya sub-province (south-west of the platform) with rounded diamonds; Aldan sub-province (south-east of SDP) with finds of individual rounded diamonds.

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Zhang, Kai, Chenshu Wu, Chaofan Yang, Yi Zhao, Kehong Huang, Chunyi Peng, Yunhao Liu y Zheng Yang. "ChromaCode". En MobiCom '18: The 24th Annual International Conference on Mobile Computing and Networking. New York, NY, USA: ACM, 2018. http://dx.doi.org/10.1145/3241539.3241543.

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Fornes, Marc. "Chromatae". En ACADIA 2014: Design Agency. ACADIA, 2014. http://dx.doi.org/10.52842/conf.acadia.2014.161.

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Akram, Waseem, Abdul Mateen, Ibrahim Qazi y Ali Hussain. "Development and characterization of cost effective wear and corrosion resistant HVOF sprayed chromite coatings and hard chrome plating". En 2019 16th International Bhurban Conference on Applied Sciences and Technology (IBCAST - 2019). IEEE, 2019. http://dx.doi.org/10.1109/ibcast.2019.8667168.

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Baishibekov, A., D. Purwaningsih, G. Toilanbay y Khaldun M. Al Azzam. "Comparative Analysis of Sorbents on Chromate Ion (VI) Sorption and Desorption: Influence of Composition and pH from Ilmenite Processing Solutions". En Challenges of Science, 117–22. Institute of Metallurgy and Ore Beneficiation JSC, Satbayev University, 2024. http://dx.doi.org/10.31643/2024.17.

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In this work, the processes of sorption and desorption of chromate ions from the solution obtained as a result of the processing of high-chromium ilmenite concentrate were studied using sorbents: Amberlite IR120 (Na), Amberlite IRA-35, PuroliteA-100, LewatitMono Plus M-500. The influence of pH factor and sorption system composition on the sorption process of chromate ions (VI) was investigated. Different polymers were tested to evaluate their combined effect on the recovery of chromate ions. A correlation was found between the increase in the efficiency of the sorption process of chromate ions (98%) and a decrease in pH from pH 13.5 to pH 2.5. In addition, the sorption process was improved at higher sorbent concentrations and the desorption efficiency increased at higher molar concentrations of sodium hydroxide (NaOH). The study's results will serve for the optimization of sorption processes for the extraction of chromate ions (VI) with the participation of various polymeric sorbents in the industry.

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Yamashita, Atsushi, Hiroki Agata y Toru Kaneko. "Every color chromakey". En 2008 19th International Conference on Pattern Recognition (ICPR). IEEE, 2008. http://dx.doi.org/10.1109/icpr.2008.4761643.

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Tanuwidjaja, Enrico, Derek Huynh, Kirsten Koa, Calvin Nguyen, Churen Shao, Patrick Torbett, Colleen Emmenegger y Nadir Weibel. "Chroma". En UbiComp '14: The 2014 ACM Conference on Ubiquitous Computing. New York, NY, USA: ACM, 2014. http://dx.doi.org/10.1145/2632048.2632091.

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Informes sobre el tema "Chromace"

Brenan, J. M., K. Woods, J. E. Mungall y R. Weston. Origin of chromitites in the Esker Intrusive Complex, Ring of Fire Intrusive Suite, as revealed by chromite trace element chemistry and simple crystallization models. Natural Resources Canada/CMSS/Information Management, 2021. http://dx.doi.org/10.4095/328981.

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To better constrain the origin of the chromitites associated with the Esker Intrusive Complex (EIC) of the Ring of Fire Intrusive Suite (RoFIS), a total of 50 chromite-bearing samples from the Black Thor, Big Daddy, Blackbird, and Black Label chromite deposits have been analysed for major and trace elements. The samples represent three textural groups, as defined by the relative abundance of cumulate silicate phases and chromite. To provide deposit-specific partition coefficients for modeling, we also report on the results of laboratory experiments to measure olivine- and chromite-melt partitioning of V and Ga, which are two elements readily detectable in the chromites analysed. Comparison of the Cr/Cr+Al and Fe/Fe+Mg of the EIC chromites and compositions from previous experimental studies indicates overlap in Cr/Cr+Al between the natural samples and experiments done at &gt;1400oC, but significant offset of the natural samples to higher Fe/Fe+Mg. This is interpreted to be the result of subsolidus Fe-Mg exchange between chromite and the silicate matrix. However, little change in Cr/Cr+Al from magmatic values, owing to the lack of an exchangeable reservoir for these elements. A comparison of the composition of the EIC chromites and a subset of samples from other tectonic settings reveals a strong similarity to chromites from the similarly-aged Munro Township komatiites. Partition coefficients for V and Ga are consistent with past results in that both elements are compatible in chromite (DV = 2-4; DGa ~ 3), and incompatible in olivine (DV = 0.01-0.14; DGa ~ 0.02), with values for V increasing with decreasing fO2. Simple fractional crystallization models that use these partition coefficients are developed that monitor the change in element behaviour based on the relative proportions of olivine to chromite in the crystallizing assemblage; from 'normal' cotectic proportions involving predominantly olivine, to chromite-only crystallization. Comparison of models to the natural chromite V-Ga array suggests that the overall positive correlation between these two elements is consistent with chromite formed from a Munro Township-like komatiitic magma crystallizing olivine and chromite in 'normal' cotectic proportions, with no evidence of the strong depletion in these elements expected for chromite-only crystallization. The V-Ga array can be explained if the initial magma responsible for chromite formation is slightly reduced with respect to the FMQ oxygen buffer (~FMQ- 0.5), and has assimilated up to ~20% of wall-rock banded iron formation or granodiorite. Despite the evidence for contamination, results indicate that the EIC chromitites crystallized from 'normal' cotectic proportions of olivine to chromite, and therefore no specific causative link is made between contamination and chromitite formation. Instead, the development of near- monomineralic chromite layers likely involves the preferential removal of olivine relative to chromite by physical segregation during magma flow. As suggested for some other chromitite-forming systems, the specific fluid dynamic regime during magma emplacement may therefore be responsible for crystal sorting and chromite accumulation.

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Andrews, P. R. A. Chromite. Natural Resources Canada/CMSS/Information Management, 1992. http://dx.doi.org/10.4095/328637.

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Nickerson, William y Craig Matzdorf. Non-Chromate Aluminum Pretreatments. Fort Belvoir, VA: Defense Technical Information Center, marzo de 2012. http://dx.doi.org/10.21236/ada582070.

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Buchheit, Rudolph. Critical Factors for the Transition from Chromate to Chromate-Free Corrosion Protection. Fort Belvoir, VA: Defense Technical Information Center, junio de 2005. http://dx.doi.org/10.21236/ada446840.

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Buchheit, Rudolph G. Critical Factors for the Transition from Chromate to Chromate-Free Corrosion Protection. Fort Belvoir, VA: Defense Technical Information Center, diciembre de 1999. http://dx.doi.org/10.21236/ada379676.

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Duke, J. M. Stratiform chromite. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1995. http://dx.doi.org/10.4095/208048.

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Pokhmurskii, Vasyl. Effect of Chromate and Chromate-Free Organic Coatings on Corrosion Fatigue of an Aluminum Alloy. Fort Belvoir, VA: Defense Technical Information Center, febrero de 2012. http://dx.doi.org/10.21236/ada563067.

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Carpenter, David. Chromate Sampling Methods and Data Analysis. Fort Belvoir, VA: Defense Technical Information Center, septiembre de 2001. http://dx.doi.org/10.21236/ada397830.

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Duke, J. M. Podiform (ophiolitic) chromite. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1995. http://dx.doi.org/10.4095/208050.

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Kuster, K., C. M. Lesher y M. G. Houlé. Geology and geochemistry of mafic and ultramafic bodies in the Shebandowan mine area, Wawa-Abitibi terrane: implications for Ni-Cu-(PGE) and Cr-(PGE) mineralization, Ontario and Quebec. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/329394.

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The Shebandowan Ni-Cu-(PGE) deposit occurs in the Shebandowan greenstone belt in the Wawa-Abitibi terrane. This deposit is one of a few economic Ni-Cu-(PGE) deposits in the Superior Province and one of a very few deposits worldwide that contains both Ni-Cu-(PGE) and Cr-(PGE) mineralization. The mafic-ultramafic successions in the area comprise abundant flows and sills of tholeiitic basalt and lesser Al-undepleted komatiite (MgO &gt;18 wt%, Al2O3/TiO2 = 15-25), the latter indicating separation from mantle sources at shallow levels. Siliceous high-Mg basalts (MgO 8-12 wt%, SiO2 &gt; 53 wt%, TiO2 &lt; 1.2 wt%, La/Sm[MN] &lt; 1-2) are relatively abundant in the area and likely represent crustally contaminated komatiites. Ultramafic bodies in the Shebandowan mine area comprise at least three or four komatiitic sills (A-B, C, D) and at least two komatiitic flows (E, F), all of which are altered to serpentinites or talc-carbonate schists with relict igneous chromite and rare relict igneous orthopyroxene-clinopyroxene. Unit A-B contains pentlandite-pyrrhotite-chalcopyrite-pyrite-magnetite mineralization, occurring as massive sulfides, sulfide breccias, or stringers, and subeconomic chromite mineralization in contorted massive bands varying from a few millimetres up to 10 metres thick. The localization of massive and semi-massive Ni-Cu-(PGE) ores along the margins of Unit A and the paucity of disseminated and net-textured ores suggest tectonic mobilization. Chromite is typically zoned with Cr-Mg-Al-rich (chromite) cores and Fe-rich (ferrichromite/magnetite) rims due to alteration and/or metamorphism, but rarely contains amoeboid magnetite cores. The thickness of chromite in Unit B is too great to have crystallized in cotectic proportion from the komatiitic magma and a model involving dynamic upgrading of magnetite xenoliths derived from interflow oxide facies iron formations is being tested.

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