Добірка наукової літератури з теми "Processus de galvanisation"

Description of Latvian Metal Production and Processing Enterprises' Air Emissions The metal production and processing sector in Latvia has acquired a stable position in the national economy. Smelting of ferrous and nonferrous metals, production of metalware, galvanisation, etc. are developed in Latvia. The metal production and processing sector has an impact on air quality due to polluting substances which are released in the air from metal treatment processes. Therefore it is necessary to determine the total volume of emissions produced by the metal production and processing sector in Latvia. This article deals with the air polluting emissions of the Latvian metal production and processing industry, and sets the optimum sector emission volumes using the emissions benchmark methodology.

Summary. Usually, the clinical basis of neurostomatological diseases is the lesion of various parts of the nervous system that provide innervation of the oral cavity and face. The main nerves whose damage leads to the development of neurostomatological diseases are the trigeminal, facial, intermediate, lingual, vagus and hyoid nerves. Among them, the trigeminal nerve system is most often affected. The causes can be odontogenic diseases such as pathological processes of the dentition and ineffective or incorrect methods of their treatment (traumatic complex tooth extraction, including the presence of bone fragments, root remnants in the socket, pulpitis and periodontitis, galvanisation phenomena when using various methods for filling and prosthetics, poorly made dentures, gingivitis, etc.) In the lecture, we tried to highlight the lesions of the trigeminal nerve system in dental diseases, emergency care, treatment and rehabilitation. Key words: trigeminal neuralgia, dental diseases, emergency care.

Concerning environmental safety and mitigating the risk of water pollution, the electroplating industry, historically reliant on the use of elevated concentrations of heavy metals to achieve high-quality products, faces a crucial challenge in monitoring wastewater enriched with these metals, notorious for their adverse effects on ecosystems and human health. Chromium, in both oxidation states Cr (III) and Cr (VI), emerges as a prominently employed metal, yielding noteworthy outcomes throughout the galvanisation process. This research showcases the prototype of an automatic in situ sensor tailored to industry sustainability efforts to facilitate real-time monitoring and efficient water management. This custom sensor, characterized by sensitivity, reliability, and user-friendliness, utilizes UV-Vis colorimetric principle to detect Cr in both oxidation forms ranging from grams per litre (g/L) to parts per million (ppm). This is made possible by the unique vibrant colours induced by chromium ions, enabling the precise measurement of analyte concentrations. Thanks to 3D printing, this sensor system interacts with customized parts, designed and validated through simulation processes, for filtering out particulate that may interfere with the analysis. The outcome represents a synergistic blend of technology and environmental responsibility, aligning industrial processes with the goal of safeguarding water resources and ecosystems.

Articulating the research priorities of government is one mechanism for promoting the production of relevant research to inform policy. This study focuses on the Areas of Research Interest (ARIs) produced and published by government departments in the UK. Through a qualitative study consisting of interviews with 25 researchers, civil servants, intermediaries and research funders, the authors explored the role of ARIs. Using the concept of boundary objects, the paper considers the ways in which ARIs are used and how they are supported by boundary practices and boundary workers, including through engagement opportunities. The paper addresses the following questions: What boundaries do ARIs cross, intended and otherwise? What characteristics of ARIs enable or hinder this boundary-crossing? and What resources, skills, work or conditions are required for this boundary-crossing to work well? We see the ARIs being used as a boundary object across multiple boundaries, with implications for the ways in which the ARIs are crafted and shared. In the application of ARIs in the UK policy context, we see a constant interplay between boundary objects, practices and people all operating within the confines of existing systems and processes. For example, understanding what was meant by a particular ARI sometimes involved ‘decoding’ work as part of the academic-policy engagement process. While ARIs have an important role to play they are no magic bullet. Nor do they tell the whole story of governmental research interests. Optimizing the use of research in policy making requires the galvanisation of a range of mechanisms, including ARIs.

De tous les éléments d'addition intervenant dans la galvanisation, l'aluminium est de loin le plus utilisé. Un examen attentif des couches de galvanisation montre que les phénomènes observés correspondent à des équilibres métastables bien qu'ils soient le plus souvent interprétés à partir de diagrammes stables. Dans ce travail, nous établissons une nette distinction entre diagramme stable et métastable. Nous montrons en particulier que la couche delta peut dans un premier temps dissoudre une grande quantité d'aluminium pour ensuite se transformer en une nouvelle phase de structure gamma 2, phase du système Fe-Zn difficilement synthétisée. D'une façon générale, le diagramme métastable se caractérise par une sursaturation de toutes les phases, à l'exception de la ferrite. Une analyse thermodynamique du diagramme nous a permis de suivre l'évolution des potentiels chimiques le long des chemins de diffusion

Les objectifs de cette thèse sont de déterminer un modèle à la fois suffisamment précis mais numériquement exploitable pour proposer des méthodologies de placement de capteurs et d'actionneurs pour le contrôle actif de vibration dans une ligne de galvanisation. La galvanisation consiste à recouvrir un métal (dans notre étude : de l'acier) par une couche protectrice de zinc qui évite la corrosion due à l'air. L'épaisseur de cette couche doit être constante pour garantir les propriétés mécaniques et l'état de surface du produit. Dans une ligne de galvanisation, la bande d'acier en mouvement est chauffée puis plongée dans un bain de zinc liquide avant d'être essorée par des buses projetant de l'air. L'air pulsé, ainsi que la rotation des cylindres d'entrainement de la bande - entre autres - créent des vibrations qui viennent perturber l'essorage et donc la régularité du dépôt de zinc. Un contrôle actif est donc nécessaire, par exemple au moyen d'électro-aimants placés de part et d'autre de la bande d'acier en mouvement. Dans un premier temps, un modèle de comportement de la bande d'acier dans la ligne de galvanisation prenant en compte la présence et la propagation des vibrations a été obtenu par discrétisation spatiale d'une équation aux dérivées partielles. Ce modèle de type espace d'état a été validé en simulation et expérimentalement sur une ligne de galvanisation pilote d'ArcelorMittal Research à Maizières-lès-Metz. Une fois ce modèle établi, l'objectif de l'étude est la recherche du placement optimal de capteurs, pour mesurer le plus efficacement les vibrations de la bande, mais également d'actionneurs pour minimiser l'amplitude de ces vibrations par une loi de commande adaptée. Ces problèmes de placements optimaux sont au cœur des thématiques de contrôle actif des vibrations et se retrouvent dans de nombreux domaines d'application. Une méthode de placement basée sur la maximisation des Grammiens a été proposée en vue de réduire l'impact des perturbations sur le système. Différentes stratégies de contrôle ont été envisagées telles que le retour d'état observé et le retour d'état étendu observé pour améliorer les résultats en tenant compte de l'estimation des perturbations par un observateur PI (proportionnel-intégral). Des résultats de simulations et expérimentaux illustrent les résultats obtenus
The aims of the present PhD thesis are to determine a model that is both sufficiently accurate and numerically exploitable to propose optimal placement of sensors and actuators for active vibration control in a galvanizing line. A continuous hot-dip galvanizing process consists in covering a metal (here: a steel band) by a protective layer of zinc which avoids the corrosion due to the air. The thickness of this layer must be constant to guarantee the mechanical properties and surface condition of the product. In a galvanizing line, the moving steel strip is heated and then immersed in a liquid zinc bath before being wiped out by nozzles projecting air. The air flow, as well as the rotation of the driving rolls, among other things, creates vibrations affecting the wiping process and thus the regularity of the zinc deposit. Active control is therefore necessary, for example by means of electromagnets placed on either side of the moving steel strip. In a first step, a behavioral model of the steel strip taking into account the presence and propagation of vibrations was obtained by spatial discretization of a partial differential equation. This state space model was validated in simulation and experimentally on a pilot galvanizing line of ArcelorMittal Research in Maizières-lès-Metz. Once this model is established, the objective of the study is to find the optimal placement of sensors, to measure the vibrations of the strip as efficiently as possible, but also of actuators to minimize the amplitude of these vibrations by an appropriate control law. These problems of optimal placement are at the heart of the issues of active vibration control and are found in many fields of application. An optimal placement method based on Gramian maximization has been proposed in order to reduce the impact of disturbances on the system. Different control strategies have been considered such as (i) observed state feedback based on Kalman filter and LQ regulator; and (ii) extended observed state feedback to improve the results by also taking into account the disturbance estimation provided by a PI (proportional-integral) observer. Simulation and experimental results illustrate the thesis contributions