Journal articles on the topic 'Qualité graphique'
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Maallem, S., E. Lanoy, S. Postel-Vinay, and A. Moussa. "Interface graphique validant la qualité des données cliniques saisies dans Excel." Revue d'Épidémiologie et de Santé Publique 62 (September 2014): S237—S238. http://dx.doi.org/10.1016/j.respe.2014.06.215.
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Ross, John. "Data is power: resistance is futile." CJEM 2, no. 01 (January 2000): 27–28. http://dx.doi.org/10.1017/s1481803500004395.
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RÉSUMÉ: Le mouvement d’ACQ (amélioration continue de la qualité), avec l’aide d’Intel et de Microsoft, fera de la prochaine décennie l’ère des données. Les départements d’urgence à travers le pays travaillent présentement à mettre sur pied des systèmes de collecte de données pour surveiller les profils de gravité des cas des patients, les temps d’attente, les durées de séjours à l’urgence, les habitudes de demandes d’épreuves, les pourcentages de demandes de consultation, l’utilisation des lits et les taux d’hospitalisation, et ce, pour chaque médecin. Mais ces données sont-elles fiables? Ou valables? Comment seront-elles utilisées pour juger le travail des médecins? Quelle sera la pénalité pour le médecin si sa surface sous la courbe tend à remonter? Peut-on quantifier les soins aux patients à l’aide d’un graphique? Et y a-t-il une corrélation directe ou une corrélation inverse entre la rapidité du médecin et la qualité des soins? L’ère de l’information est arrivée, mais les données feront-elles de nous de meilleurs médecins?
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Gharbi, Mohamed, and Mohamed Aymen Labiod. "Une application comparative pour l’enseignement des méthodes de compression d’images par transformées orthogonales." J3eA 21 (2022): 2039. http://dx.doi.org/10.1051/j3ea/20222039.
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Nous proposons dans cette contribution une interface graphique comme outil pédagogique pour l’enseignement des méthodes de compression par transformées orthogonales utilisées dans l’encodage d’images. Cet outil est utilisé dans l’enseignement proposé aux étudiants en MASTER du département Développement, Recherche, Enseignement en Audiovisuel et Multimédia (DREAM) de l’Université Polytechnique Hauts-de-France (Valenciennes – France). Les offres de formation s’appuient notamment sur un enseignement du traitement de signal, des images ainsi que la compression des images et de la vidéo. Les deux aspects analogique et numérique du traitement du signal sont enseignés. Cet interface graphique a été développé pour permettre aux étudiants de mieux appréhender l’influence des différents paramètres intervenant dans une chaîne de compression numérique des images. A travers cet outil, nous proposons aux étudiants une nouvelle approche à la compréhension des transformées matricielles utilisées dans l’encodage des images et de la quantification sur la qualité des images compressées par plusieurs transformées. En effet, cet outil, par le biais de l’ajustement des différents paramètres intervenant dans le chaîne de compression, permet aux étudiants d’étudier et de comparer plusieurs transformées orthogonales à savoir la Transformée en Cosinus Discrète (DCT), la Transformée de Karhunen-Loève (KLT) sous les deux versions séparable ou non, la Transformation de Fourier Discrète (TFD) ainsi que la Transformée d’Hadamard. Ainsi, visuellement par le biais de l’image reconstruite et par le rapport signal à bruit cet outil permet aux étudiants d’apprécier le choix des paramètres qu’ils ont fixés pour l’obtention de leurs résultats.
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Piriou, P., S. Dukan, Y. Levi, F. Guyon, and P. Villon. "Modélisation du comportement des biomasses bactériennes libres et fixées dans les réseaux de distribution d'eau potable." Revue des sciences de l'eau 9, no. 3 (April 12, 2005): 381–406. http://dx.doi.org/10.7202/705259ar.
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La prolifération bactérienne en réseaux de distribution d'eau potable est un souci majeur des distributeurs d'eau. La complexité des phénomènes impliqués dans la croissance bactérienne en réseaux nécessite une modélisation mathématique pour définir l'impact des différents paramètres de la qualité de l'eau et généraliser ces résultats à l'échelle du réseau de distribution. Une approche déterministe a été choisie pour développer cette modélisation prédictive de la croissance bactérienne dans les systèmes de distribution. Le modèle prend en compte : la croissance de fa biomasse libre et de la biomasse fixée, la consommation en nutriments exprimés par le CODB, l'action bactéricide du chlore sur la flore libre et la dore fixée, la déposition des bactéries en suspension et le détachement des bactéries fixées. Le modèle propose une approche originale pour la modélisation de l'action bactéricide du chlore. Par ailleurs, différentes formulations du détachement ont été testées algébriquement pour définir la modélisation la plus adaptée à notre système d'équations. Ce modèle a été couplé au logiciel de modélisation hydraulique IMCCOI.O développé par la SAFEGE. Utilisant les données hydrauliques et de géométrie générées par PICCOLO, le modèle prédit les numérations bactériennes en chaque noeud et sur chaque arc du réseau de distribution. Utilisant l'interface graphique de PICCOLO, le modèle permet une visualisation de l'évolution de la qualité bactérienne par cartographie. Des simulations ont été réalisées sur de nombreux réseaux présentant des tailles et des niveaux de complexité variables. Le modèle a été validé à partir de campagnes de prélèvements sur sites. Ce modèle permettant de simuler l'évolution de la qualité bactériologique à l'échelle du réseau est un outil unique pour le diagnostic et la gestion qualitative des systèmes de distribution d'eau potable.
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BESNIER, M., M. GUITTET, P. BINDER, and J. MAUHOURAT. "addictovideos.fr : un référentiel de vidéo en ligne en addictologie." EXERCER 34, no. 197 (November 1, 2023): 414–19. http://dx.doi.org/10.56746/exercer.2023.197.414.
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Contexte. Les addictions sont la première cause évitable de mortalité avant 65 ans en France. Les vidéos sur internet sont un mode de communication en plein essor permettant une meilleure communication entre médecins généralistes et patients. La qualité de celles-ci est variable. Objectif. Créer un site internet rassemblant et classant les vidéos abordant les addictions. Mé thodes. Une revue des vidéos traitant de « l’addiction », durant moins de dix minutes, de langue francophone, a été réalisée sur moteur de recherche puis sur des plateformes de vidéos gratuites (YouTube®, Dailymotion® et Vimeo®). Chaque vidéo a été analysée par trois experts et répertoriée selon : son titre original, son libellé, ses auteurs, son lien internet, sa durée et sa date de publication. Secondairement, une note entre 1 (pas d’intérêt) et 4 (très intéressante) a évalué l’intérêt pour une approche formative auprès des médecins, et également pour échanger avec les patients et les informer. Pour chaque vidéo ont été caractérisés : le format du média (charte graphique), le principal mode d’expression, l’objectif principal et secondaire, et le produit principal et secondaire. Résultats. Parmi 2 522 vidéos visionnées, 287 répondaient aux critères de sélection. La majorité (59 %) des vidéos duraient de 1 à 5 minutes. Sur l’ensemble des vidéos, 83 (30 %) étaient jugés « intéressantes » ou « très intéressantes » pour le patient ; 61 (22 %) étaient « intéressantes » ou « très intéressantes » pour les soignants. Ce catalogue raisonné de vidéos traitant de l’addiction a été rendu accessible sur internet avec la création du site http://addictovideos.fr/. Conclusion. Cette étude propose un outil exploitable, tant par les soignants que par les patients. Le nombre de vidéos jugées intéressantes pour les patients ou les soignants est faible, à mettre en lien avec la sévérité des critères de jugement. Cette sélection rigoureuse est garante de qualité pour l’utilisation par les personnes cibles.
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Coquelin, A., M. Erbault, N. Le Guen, A. Solomiac, S. Morin, and L. May-Michelangeli. "Intérêt de la représentation graphique de la variabilité régionale des résultats des indicateurs de qualité des parcours pour orienter les politiques de santé régionales." Revue d'Épidémiologie et de Santé Publique 71 (March 2023): 101527. http://dx.doi.org/10.1016/j.respe.2023.101527.
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Pierre, UTCHINGA WELA. "APPORT DE MARKETING STRATEGIQUE SUR LA FIDELISATION DE LA CLIENTELE AU CENTRE HOSPITALIER LUMBULUMBU." IJRDO - Journal of Business Management 8, no. 11 (November 24, 2022): 8–21. http://dx.doi.org/10.53555/bm.v8i11.5445.
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Le souci majeur qui nous a poussés à réaliser cette recherche est celui de plaintes de clients du Centre Hospitalier Lumbulumbu sur le prix de soins médicaux qui n’est pas adapté aux conditions socio-écomiques de la population se trouvant dans cette ville, au vu de cette réalité nous proposons d’appliquer le marketing relationnel et événementiel sur la fidélisation de la clientèle au CHLL, la question suivante a été formulé : quelles actions marketing que le Centre Hospitalier Lumbulumbu doit-il mener pour fidéliser ses patients conventionnés et privés ? Pour mener cette recherche à bon port nous avons recouru aux méthodes historiques, inductives et analytiques. Ces méthodes ont été soutenues par les techniques d’observation directe, questionnaire et documentaire et la technique statistique pour le traitement de données.
En effet, après avoir analysé les réponses fournies par certains clients du CHLL, nous constatons que le réajustement de prix à toutes les catégories de la clientèle, la satisfaction des attentes de malades, collaboration étroite des autorités du CHLL et sa clientèle, la qualité de prise en charge, l’accueil et la disponibilité des médecins spécialistes sont des atouts importants pouvant permettre au Centre Hospitalier Lumbulumbu de fidéliser davantage sa clientèle, car dit-on un pauvre client est un roi face à un investisseur riche du fait qu’il investit en fonction de ce client. Néanmoins, l’aspect marketing étant négligé dans cette structure comme vous les remarquez au graphique N°09, or le marketing est un vecteur de rentabilité indéniable pour toute structure dans le sens que le client est toujours exigeant et volatil.
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AKA, Natchia, Abou Traoré, Nadi Paul Dangui, and Yao Dakro Albert Gboko. "Suivi de la turbidité et des matières en suspension dans les rivières côtières en milieu tropical : cas de la Mé et de l’Agneby (sud-est de la Cote d’Ivoire)." Journal of Applied Biosciences 183 (March 31, 2023): 19103–22. http://dx.doi.org/10.35759/jabs.183.1.
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Au Sud de la Côte d’Ivoire, l’État fait recours aux rivières côtières Mé et Agnéby pour pallier le déficit en eau potable destinée aux populations. Cependant, la forte turbidité et les concentrations élevées des matières en suspension dans ces cours d’eaux sont des indicateurs de la dégradation de leur qualité. Objectif Cette étude vise à évaluer la dynamique de la turbidité et des Matières en Suspension (MES) au cours du temps. Méthodologie et Résultats Pour ce faire, des mesures journalières de turbidité et de MES ont été réalisées sur un total de 277 échantillons d’eau prélevés dans la Mé et de 261 dans l’Agnéby sur la période allant de juin 2019 à mai 2020. Les concentrations en MES et ses différentes composantes ont été déterminées par gravimétrie et la turbidité par néphélométrie. La représentation graphique en nuage de points des couples de données turbidité-MES a permis d’établir la nature de leur relation. Les résultats montrent que dans la Mé, les concentrations en MES varient de 20 à 1000 mg/L et la turbidité oscille entre 53,94 et 1845 NTU. Ces valeurs élevées perdurent toute la durée de l’étude et indiquent que les eaux sont de qualité médiocre. Par contre, dans l’Agnéby, les eaux sont de qualité bonne à moyenne. Elles sont moins chargées en MES, avec des valeurs comprises entre 2 et 300 mg/L et une turbidité comprise entre 3,89 et 242 NTU. Pour des teneurs élevées en MES, la fraction minérale l’emporte sur la fraction organique. La grande variabilité des MES et de la turbidité des eaux est liée aux activités agricoles et d’extraction de sable ainsi que de l’orpaillage illégal. Il existe une très bonne corrélation linéaire entre la turbidité et les MES dans la Mé contrairement à l’Agnéby. Conclusion et Application des résultats : Cette étude a mis en lumière les conséquences de l’orpaillage illégal sur la qualité de la rivière Mé. C’est un outil d’aide à la décision qui permettra la surveillance en continu de la qualité des cours d’eau par la mesure de la turbidité seulement et la prise de décisions par les États contre le fléau de l’orpaillage Mots-clés : Rivières côtières, Mé, Agnéby, turbidité, Matières en Suspension 19103 Aka et al., J. Appl. Biosci. Vol : 183, 2023 Suivi de la turbidité et des matières en suspension dans les rivières côtières en milieu tropical : cas de la Mé et de l’Agneby (sud-est de la Cote d’Ivoire) Monitoring turbidity and total solid suspended in coastal rivers in tropical environment: case of Mé and Agnéby (southeast of Côte d’Ivoire) ABSTRACT In the south of Côte d'Ivoire, the State uses the Mé and Agnéby coastal rivers to make up for the lack of drinking water to supply the populations. However, the high turbidity and high concentrations of Total suspended solids in these watercourses are indicators of the deterioration of their quality. Objective: To evaluate the dynamics of turbidity and Total suspended solids (TSS) over time. Methodology and results: To do this, daily turbidity and TSS measurements were taken on a total of 277 water samples taken from the Mé and 261 from the Agnéby over the period from June 2019 to May 2020. TSS concentrations and its various components were determined by gravimetry and turbidity by nephelometry. The graphical representation in point cloud of the turbidity-TSS data pairs made it possible to establish the nature of their relationship. The results show that in the Mé, the TSS concentrations vary from 20 to 1000 mg/L and the turbidity oscillates between 53.94 and 1845 NTU. These high values persist throughout the duration of the study and indicate that the water is of poor quality. On the other hand, in Agnéby, the waters are of good to average quality. They are less loaded with suspended solids, with values between 2 and 300 mg/L and the turbidity is between 3.89 and 242 NTU. For high SS contents, the mineral fraction prevails over the organic fraction. The great variability of suspended solids and water turbidity is linked to agricultural activities and sand extraction as well as illegal gold panning. There is a very good linear correlation between turbidity and suspended solids in the Mé unlike in the Agnéby. Conclusions and applications of results: This study shed light on the consequences of illegal gold panning on the quality of the Mé River. It is a decision support tool that will allow continuous monitoring of the quality of waterways by measuring turbidity and decision-making by States against the scourge of gold panning. Keywords: Coastal Rivers, Mé, Agnéby, turbidity, suspended solids
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Hopman, W. M., M. B. Harrison, H. Coo, E. Friedberg, M. Buchanan, and E. G. VanDenKerkhof. "Liens existant entre les maladies chroniques, l’âge et l’état de santé physique et mental." Maladies chroniques au Canada 29, no. 3 (May 2009): 121–31. http://dx.doi.org/10.24095/hpcdp.29.3.03f.
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Le présent article examine les liens existant entre les maladies chroniques, l’âge et la qualité de vie liée à la santé (QVLS) physique et mentale, à l’aide de données recueillies dans le cadre de dix études portant sur cinq maladies chroniques. La QVLS a été mesurée à l’aide du SF-36 ou de sa version sommaire, le SF-12. Les scores du Sommaire de la composante physique (SCP) et du Sommaire de la composante mentale (SCM) ont été représentés sur un graphique selon la maladie chronique, par groupes d’âge de 10 ans, et comparés avec des données normatives ajustées en fonction de l’âge et du sexe. Les modèles de régression linéaire relatifs au SCP et au SCM ont été corrigés en fonction des variables confusionnelles existantes. Sur les 2 418 participants qui composaient l’échantillon, 129 sujets étaient atteints d’insuffisance rénale, 366, d’arthrose, 487, d’insuffisance cardiaque, 1 160 présentaient des plaies chroniques (p. ex., ulcère à la jambe) et 276 étaient atteints de sclérose en plaques (SEP). D’importantes différences ont été notées quant au SCP entre les données normatives et les scores moyens des sujets atteints de maladies chroniques, mais ces différences étaient négligeables pour ce qui était du SCM. Le fait d’être une femme et de présenter des comorbidités était associé à une QVLS moins bonne; l’âge avancé était associé à un SCP plus faible et à un meilleur SCM. Cette étude a permis de confirmer que même si la fonction physique pouvait être gravement affectée à la fois par des maladies chroniques et l’âge avancé, la santé mentale demeure relativement bonne et stable.
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Cléry, Isabelle, and Marc Pierrot-Deseilligny. "Une interface ergonomique de calcul de modèles 3D par photogrammétrie." Revue Française de Photogrammétrie et de Télédétection, no. 196 (April 15, 2014): 40–51. http://dx.doi.org/10.52638/rfpt.2011.36.
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De nombreux logiciels du commerce proposent de créer des modélisations en 3D d'objets ou de scènes à partir uniquement de photographies. Cependant les professionnels, notamment les archéologues et les architectes, ont un certain nombre de contraintes qui restreignent fortement le choix du logiciel, telles que des ressources financières limitées, des connaissances peu approfondies en photogrammétrie et en informatique, des impératifs qui limitent le temps d'acquisition et de traitement, et enfin des attentes précises en terme de qualité, de précision et de complétude de la modélisation. Le laboratoire MATIS a développé un ensemble d'outils libres, open source, qui permettent d'effectuer l'ensemble des étapes du traitement d'un chantier photogrammétrique et qui fournissent des modèles 3D très denses et précis grâce à la rigueur de l'approche photogrammétrique ; ils représentent donc une solution intéressante pour ces professionnels du point de vue algorithmique.Cependant ils ont été développés pour des applications de recherche et sont donc peu ergonomiques pour le public non photogrammètre et non informaticien. C'est pourquoi une interface graphique est en cours de développement afin de fournir un accès simplifié et unifié à ces outils, notamment aux architectes et aux archéologues. Grâce à l'interface, l'utilisateur peut manipuler les images d'un même chantier et contrôler chaque étape du traitement qui comprend : le calcul automatique de points homologues entre les images, l'estimation des poses de la caméra et le calcul des modèles 3D. Les résultats peuvent être convertis en cartes de profondeur ombrées ou en nuages denses de points 3D (au format standard ply), et peuvent être affichés directement par l'interface. Pour offrir la possibilité de traiter des chantiers suffisamment variés, tout en masquant la complexité du paramétrage, la démarche retenue est de présenter à l'utilisateur un accès par grande famille de prises de vue, par exemple : chantier convergent, relevé de façades, chantier aérien sub-vertical, modélisation d'intérieur. . . Une attention particulière est apportée à la qualité de la documentation et à la portabilité du produit sur les principaux types d'ordinateur grand public (Linux, Mac et Windows). Cette interface, bien que non finalisée, permet déjà d'effectuer l'intégralité du traitement de chantiers de type convergent et est disponible en ligne. Des utilisateurs issus des différentes communautés de professionnels ciblées (archéologie, architecture, géologie, photogrammétrie architecturale) l'ont déjà testée et l'interface est régulièrement mise à jour afin de l'adapter aux remarques et demandes de ces testeurs.
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Nero, Marcelo Antonio, Rodrigo Amaral Lapa, and Simone Sayuri Sato. "Proposta de uma metodologia economica para o desenvolvimento de SIG 3D." Revue Française de Photogrammétrie et de Télédétection, no. 198-199 (April 21, 2014): 71–77. http://dx.doi.org/10.52638/rfpt.2012.74.
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Le développement d’un système d’informations géografiques (SIG) tridimensionnel a besoin d’importer des éléments solides créés en trois dimensions. L’acquisition de ces éléments est généralement effectuée au moyen d’un LIDAR (Light Detection And Ranging). Une autre possibilité est la cartographie des façades de bâtiments, qui en règle générale est réalisée par la prise d'images géocodées au moyen d’un GPS et d’un système inertiel. Ensuite, un laborieux travail d'édition graphique doit être effectué. Evidemment, si le niveau de détail de la représentation des éléments est plus grand, le temps et le coût de l'acquisition de données 3D seront aussi très grands. Cette forme de développement d'unprojet de SIG 3D pour les applications comme la distribution d'énergie électrique est encore peu viable pour la réalité brésilienne en raison des coûts élevés d'acquisition 3D. Ainsi, pour rendre viable l'utilisation de ces outils dans un environnement SIG 3D dans une entreprise d'énergie électrique nationale, nous avons développé une méthodologiealternative à bas coût qui sera présentée dans ce travail. L'alternative est l'utilisation de la restitution photogrammétrique et l'utilisation des données suivantes : des photographies aériennes d’archive à l'échelle 1:8.000; une base cartographique plani-altimétrique permettant l’orientation externe d’images à l'échelle 1:2.000 pour l’obtention du modèle stéréoscopique et la restitution des éléments importants; une image multispectrale à haute résolution du satellite Quick BIRD, utilisée comme toile de fond et pour la texturation du modèle numérique du terrain. Le développement du projet a nécessité l’utilisation de logiciels et bibliothèques Opensource comme l'ensemble VTP (Virtual Terrain Project), qui inclut OGR, GDAL, vtdata et vtlib compatibles avec MFC (Microsoft Foundation Class), GDI+ (Graphics Device Interface Plus) ainsi que la base de données PostgreSQL. La modélisation des données a été réalisée de manière à simplifier l'acquisition des données tridimensionnelles et donc, réduire les coûts, dans le but d’appliquer le SIG 3D aux réseaux dedistribution d'énergie électrique. Des analyses de qualité du positionnement relatif ont ensuite réalisée, les résultats sontprésentés dans cet article.
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Inusa, S. K., and B. F. Muhammad. "Evaluation of sensory properties of Kilishi prepared from fermented cattle and camel beef in Semi-arid Nigeria." Nigerian Journal of Animal Production 48, no. 5 (November 10, 2021): 113–23. http://dx.doi.org/10.51791/njap.v48i5.3191.
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Meat fermentation is an important processing method with enormous nutritional and health benefits. A study was conducted to examine the sensory properties of fermented cattle and camel beef Kilishi. The effects of meat type, age and packaging on this meat quality attribute were evaluated. The experimental meat samples were fermented before utilized in Kilishi processing. The chunks of meat were sliced and then inoculated with lactic meat starter culture at three concentrations (2.5, 5.0 and 7.5 g /100 ml w/v). Kilishi samples for the sensory assessment were taken from each product lot. The experiment for the second trial was laid in a 2 x 3 x 4 factorial arrangement in a completely randomized design. The factors are two animal species (cattle and camel) aged 3, 5 and 8 years and above and four packaging arrangements: brown paper (B), polyvinyl chloride (P), aluminium foil and polyvinyl chloride (AP), brown paper and polyvinyl chloride (BP). Data generated were analysed by analysis of variance using SPSS Version 20.0 and GraphPad Instat while significantly different means were separated with Tukey HSD test. The result of sensory evaluation of the experimental Kilishi indicated that colour was ranked high and the product prepared from animals aged 5 years (middle age) and packaged in polyvinyl chloride material was the one preferred. It was concluded that fermentation and packaging improved the sensory quality of the product. Fermentation of cattle and camel beef of animals aged 5 years using 2.5% meat starter culture and the use of PVC-based package were recommended in semi-arid environment of Nigeria.
La fermentation de la viande est une méthode de traitement importante avec d'énormes avantages nutritionnels et de santé. Cette étude a été menée pour examiner les propriétés sensorielles des bovins fermentés et du Kilishi de bovins à base de chameaux. Les effets du type de viande, de l'âge et de l'emballage sur cet attribut de qualité de la viande ont été évalués. Les échantillons de viande expérimentaux étaient fermentés avant l'utilisation de la transformation du Kilishi. Les morceaux de viande ont été tranchés puis inoculés avec une culture de démarreur de la viande lactique à trois concentrations (2,5, 5,0 et 7,5 g / 100 ml w/v). Les échantillons de Kilishi pour l'évaluation sensorielle ont été prélevés sur chaque lot de produit. L'expérience du deuxième essai a été déposée dans un arrangement factoriel de 2 x 3 x 4 dans une conception complètement randomisée. Les facteurs sont deux espèces animales (bovins et chameaux) âgés de 3, 5 et 8 ans et plus et quatre arrangementsd'emballage: papier brun (P), chlorure de polyvinyle (C), feuille d'aluminium et chlorure de polyvinyle (FC), papier brun et polyvinyle chlorure (PC). Les données générées ont été analysées par analyse de la variance à l'aide de SPSS version 20.0 et du graphique PadinStat, tandis que des moyens nettement différents ont été séparés avec un test de Tukey DFS. Le résultat de l'évaluation sensorielle des Kilishi expérimentaux a indiqué que la couleur était élevée et le produit préparé à partir d'animaux âgés de 5 ans (âge moyen) et emballé dans des matériaux de chlorure de polyvinyle était celui préféré. Il a été conclu que la fermentation et l'emballage ont amélioré la qualité sensorielle du produit. Fermentation du bétail et du bœuf à base de chameaux d'animaux âgés de 5 ans en utilisant une culture de démarrage de 2,5% de la viande et l'utilisation de colis à base de PVC ont été recommandées dans un environnement semi-aride du Nigéria.
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Pelard, Emmanuelle. "Le nomadisme du signe dans les « pseudographies » de Christian Dotremont et d’Henri Michaux." Cygne noir, no. 1 (July 26, 2022): 36–52. http://dx.doi.org/10.7202/1090994ar.
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Cet article souligne les limites d’une approche sémiologique dualiste à l’épreuve d’oeuvres autant plastiques que littéraires qui présentent des signes hybrides – c’est-à-dire disposant, à la fois ou successivement, de qualités iconiques, plastiques et scripturales. Il est difficile de saisir le régime sémiotique à l’oeuvre dans le logogramme de Christian Dotremont et dans les idéogrammes imaginaires d’Henri Michaux si l’on ne considère pas le glissement permanent d’un ordre de signes à un autre, voire la double appartenance simultanée, plastique et graphique, de certains d’entre eux. Contrariant le système notationnel et/ou y échappant, déterritorialisant les fonctions de l’écriture, disposant régulièrement et alternativement des qualités du signe iconique, plastique, puis graphique, les peintures graphiques de Dotremont et de Michaux proposent un nomadisme du signe inscrit (s’agissant de sa forme comme de son statut) et requièrent une lecture intégrationnelle (Harris, 1993) – c’est-à-dire appréhender le signe graphique en prenant en compte le fait qu’il est décontextualisé et intégré à un autre système sémiotique, en l’occurrence plastique ou iconique, et vice versa.
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Illarionov, I. E., T. R. Gilmanshina, and A. A. Kovaleva. "Perspective Methods of Graphite Quality Improving." Materials Science Forum 946 (February 2019): 650–54. http://dx.doi.org/10.4028/www.scientific.net/msf.946.650.
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The influence of various methods of activation on the graphite particles average size and micro-relief of particles have been studied. It has been experimentally proved that the size of graphite particles decreases after the process of mechano-activation, however graphite particles don’t change significantly after being processed by chemical activation. It should be noted that in the course of chemical activation the state of particles surface varies on shearing cuts. Particles’ surface can be described as a poly stratified system, comprising separate complex-structured buildups of the “rosette” type, where the graphite petals are located around the reinforcing rod. Moreover, the graphite petals are placed at different angles to each other, and they are of different thickness. The empty space between these buildups is filled with graphite particles, their petals being orientated freely. The particles size decrease and the change in the particles surface state are followed by their porosity increase, which, in its turn, leads to the fact that graphite particles’ surface becomes “super-hydrophobic” and helps the capillary forces resist the filtration of the melt into the pores of graphite particles.
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Silva, Catarina, João M. P. Coelho, Manuel A. Abreu, J. Cabrita Freitas, and Campos Rodrigues. "Quality Control of Fuel Cells Channels." Materials Science Forum 514-516 (May 2006): 442–46. http://dx.doi.org/10.4028/www.scientific.net/msf.514-516.442.
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The methods of dimensional control for solid surfaces are usually contact methods. However, in fragile and reduced hardness surfaces, these methods present critical disadvantages. The method presented in this work aims to offer resources for the optimization of graphite components machined with laser through the measurement of the channels’ depth and shape. In this scope, the laser triangulation technique demonstrated to be a very useful tool in the quality control of graphite diffusers plates for fuel cell prototyping and in their future production.
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Sun, Chuanyao, Shifu Shen, Wenli Wang, Guohui Yuan, Zhenghong Huang, and Yihe Zhang. "High Quality Development of Graphite Resource and Graphite Material Industry." Chinese Journal of Engineering Science 24, no. 3 (2022): 29. http://dx.doi.org/10.15302/j-sscae-2022.03.004.
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Lee, Hee Jun, Hee Tae Lee, Hee Won Shin, Mi Seon Park, Yeon Suk Jang, Won Jae Lee, Im Gyu Yeo, et al. "Effect of Porous Graphite for High Quality SiC Crystal Growth by PVT Method." Materials Science Forum 821-823 (June 2015): 43–46. http://dx.doi.org/10.4028/www.scientific.net/msf.821-823.43.
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The effect of the porous graphite plate above the source material on properties of silicon carbide (SiC) crystals grown by Physical Vapor Transport method has been investigated. The porous graphite plate was inserted on source powder to produce a more C-rich for the polytype stability of 4H-SiC crystal and a uniform radial temperature gradient. The dendrite structure obtained from SiC source powder in the crucible with porous graphite plate was more densely formed than that in the conventional crucible. The crystal quality of 4H-SiC single crystals grown in porous graphite inserted crucible was revealed to be better than that of crystal grown SiC crystals in the conventional crucible.
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Kropivna, Alena, and Olexandr Kuzyk. "Analysis and Harmonization of National and International Quality Standards for Compacted Graphite Cast Irons." Central Ukrainian Scientific Bulletin. Technical Sciences, no. 3(34) (October 2020): 88–95. http://dx.doi.org/10.32515/2664-262x.2020.3(34).88-95.
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Ensuring and coordination of high quality indicators of materials in the foundry industry is necessary in the development of Ukraine's economy. High quality products need to be enshrined in new national standards, harmonized with international and European standards. Thus, the purpose of this work is to analyze national and international standards for quality indicators of vermicular graphite iron and their harmonization with each other. The foundry industry of Ukraine has developed mainly with the use of interstate standards - GOST, which differ significantly from European and international and requires coordination and other approaches to the development of new standards. Today there are a number of international standards: ISO, SAE, CEN, VDG, ASTM, JIS, GB, STAS, which regulate the properties of cast iron with vermicular graphite. Most standards define the range of permissible content of spherical graphite (0… 20%) in the structure of cast iron with vermicular graphite, as well as determine the shape of samples to determine the properties and provide for the determination of graphite on surfaces formed after machining castings. In accordance with the needs of the automotive industry, the Society of Automotive Engineers (SAE) has created the standard SAEJ1887 JUL2002 for cast iron with vermicular graphite. The DSTU standard in force in Ukraine regulates only the temporary resistance to tensile and elongation laid down in the brand designation. Thus, the improvement, provision and harmonization of the national standard at the vermicular graphite iron by achieving high quality indicators of materials in the foundry industry, will ensure the stability of the technological production process, and further entry into international and European markets and a qualitatively new level of domestic engineering. An analysis of the current standards in Ukraine DSTU for cast iron with vermicular graphite is given, as well as its regulated mechanical properties and recommended chemical composition. The properties of similar international and European standards for cast iron with vermicular graphite according to ISO, SAE, CEN, VDG, ASTM, JIS, GB, STAS standardization are analyzed, as well as cross-references to ISO 16112 to other standard brands of the vermicular graphite iron. The conformity of brands of materials, depending on their chemical composition and mechanical properties given in GOST, international and European indicators is found out.
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Grushevski, E., D. Savelev, L. Mazaletski, N. Savinski, and D. Puhov. "The scalable production of high-quality nanographite by organic radical-assisted electrochemical exfoliation." Journal of Physics: Conference Series 2086, no. 1 (December 1, 2021): 012014. http://dx.doi.org/10.1088/1742-6596/2086/1/012014.
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Abstract One of the promising ways to produce graphene is the technology of graphite splitting or exfoliation, both by physical or mechanical and chemical, including electrochemical methods. The product of electro exfoliation is nanographite, which is transformed into multigraphene at the subsequent stage of liquid-phase mechanical and ultrasonic disintegration. This approach demonstrates a successful method of obtaining multigraphene from available graphite raw materials. Since, already at a potential of 1.23V, during the electrolysis of water on a graphite anode, the hydroxyl anion is discharged with the formation of a very active hydroxyl radical oxidizer, it is not surprising that when the graphite electro exfoliation process is overvolted at 10V, graphite oxidation products are formed. In order to control the defectiveness of the graphene lattice by oxidation products, we carried out processes of graphite exfoliation in the presence of both a number of reducing agents ascorbic acid, sodium borohydride, hydrazine hydrate, and in the presence of industrial antioxidants radical traps (2,2,6,6-tetramethylpiperidine-1-il)oxyl (TEMPO), (2,2,6,6-tetramethyl-4 oxo-piperidine-1-yl)oxyl (IPON), a mixture of 5,8,9-bis isomers[(2,2,6,6-tetramethyl - 4 oxo-piperidine-1-yl)]-{5,8,9-[1,1’- bi(cyclopentylidene)]-2,2’,4,4’- tetraene}(YARSIM-0215). It should be noted, that the best result of preventing the oxidation of nanographite in electro exfoliation technology in our studies is the ratio of carbon to oxygen (C/O) about 69.
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Piercey, Stephen J. "Modern Analytical Facilities 2. A Review of Quality Assurance and Quality Control (QA/QC) Procedures for Lithogeochemical Data." Geoscience Canada 41, no. 1 (March 4, 2014): 75. http://dx.doi.org/10.12789/geocanj.2014.41.035.
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Quality assurance and quality control (QA/QC) are critical components of modern analytical geochemistry. A properly constructed QA/QC program identifies both the source of analytical error and provides a means of establishing confidence in and assessing limitations of analytical data. A QA/QC program involves monitoring precision, accuracy, and potential contamination from sampling to analysis. Precision can be monitored via the systematic insertion of sample, pulp, and analytical duplicates, and reference materials; the resulting data are subsequently evaluated using scatterplots, statistical tests (e.g. % relative standard deviation), Thompson-Howarth plots, and the average coefficient of variation (CVavg (%)). Accuracy is determined through the submission of reference materials and monitored using statistical tests (e.g. % relative difference, t-test) and Shewart control charts. Blanks test contamination and results are monitored using Shewart control charts.SOMMAIREL'assurance de la qualité et le contrôle de la qualité (AQ-CQ) sont deux composantes essentielles à la géochimie analytique moderne. Un programme AQ-CQ bien conçu défini à la fois la source de l'erreur d'analyse et un moyen d'établir la confiance et d’évaluer les limites des données analytiques. Un programme AQ-CQ comprend le contrôle de la précision, de l'exactitude et de la contamination potentielle, de l'étape d’échantillonnage à l'analyse. La précision peut être contrôlée via l'insertion systématique d'échantillon, de pulpes, et de doublons d'analyse, et de matériaux de référence; les données obtenues sont ensuite évaluées en utilisant des diagrammes de dispersion, des tests statistiques (pourcentage d’écart type relatif, par ex.), des courbes de Thompson-Howarth, et des coefficients de variation moyens (CVm %). La précision est déterminée par la soumission de documents de référence et de contrôle par des tests statistiques (différence relative en %, t-test, par ex.) et des graphiques de contrôle de Shewhart. La contamination d’essais à blanc et les résultats sont contrôlés par des graphiques de contrôle Shewhart.
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Shin, Hee Won, Hee Jun Lee, Hwang Ju Kim, Dong Hoon Lee, Mi Seon Park, Yeon Suk Jang, Won Jae Lee, et al. "The Role of Porous Graphite Plate for High Quality SiC Crystal Growth by PVT Method." Materials Science Forum 858 (May 2016): 113–16. http://dx.doi.org/10.4028/www.scientific.net/msf.858.113.
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The present research is focused to investigate a role of the porous graphite (PG) plate that could improve the quality of 4H-SiC crystal. The grown crystal in porous graphite inserted crucible showed the lower intensity of Al, B and Ti impurity concentration than SiC crystal grown in conventional crucible. The porous graphite plate before and after the growth process has been investigated by a Raman spectroscopy and a photoluminescence spectrum (PL). According to the analysis result, it was confirmed that the porous graphite plate had the effect of suppressing impurities supplied to SiC single crystal during the growth process.
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Choi, Jeong Min, Chae Young Lee, Dae Sung Kim, Mi Seon Park, Yeon Suk Jang, Won Jae Lee, Wei Fan, Hao Qu, Xiu Fang Chen, and Xian Gang Xu. "New Materials for Semi-Insulating SiC Single Crystal Growth by PVT Method." Materials Science Forum 963 (July 2019): 46–50. http://dx.doi.org/10.4028/www.scientific.net/msf.963.46.
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The present research was focused on the effect of porous graphite plate in TaC-coated crucible on crystal quality and resistivity of semi-insulating SiC crystals. Two SiC crystals grown with/without porous graphite plate in TaC-coated crucible were systematically compared. 6H-SiC polytype was obtained on both crystals regardless of porous graphite plate. The quality of SiC crystal grown using porous graphite plate placed in the TaC-coated crucible was slightly better than SiC crystal without porous graphite plate. SiC crystals having an average resistivity value of about 1×1010 Ωcm were obtained. In the result of COREMA measurement, the use of porous graphite plate tends to obtain wafers with better uniformity in resistivity value.
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Trolles-Cavalcante, Shimon Y. T., Asmita Dutta, Zdenek Sofer, and Arie Borenstein. "The effectiveness of Soxhlet extraction as a simple method for GO rinsing as a precursor of high-quality graphene." Nanoscale Advances 3, no. 18 (2021): 5292–300. http://dx.doi.org/10.1039/d1na00382h.
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Manoratne, C. H., S. R. D. Rosa, and I. R. M. Kottegoda. "XRD-HTA, UV Visible, FTIR and SEM Interpretation of Reduced Graphene Oxide Synthesized from High Purity Vein Graphite." Material Science Research India 14, no. 1 (June 28, 2017): 19–30. http://dx.doi.org/10.13005/msri/140104.
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Attempts were made to synthesize high quality graphite oxide (GO) and reduced graphene oxide (rGO) by using successive oxidation-reduction process of high quality vein graphite from Sri Lanka. We report the lowest optimum reduction temperature for converting GO to rGO which has been systematically studied using X-ray diffraction spectroscope (XRD) with the high temperature heating attachment (HTA) for the first time. The effect of particle size of graphite on properties of GO and rGO is also compared using commercially available graphite of particle size of ~111 mm and ball-milled graphite of particle size ~37 mm. The GO and rGO were characterized using XRD, UV-Visible spectroscopy, Fourier Transform Infrared spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The GO and rGO synthesized from ball-milled graphite showed higher oxidation and reduction properties as verified through the UV-Vis and FTIR analysis. The SEM analysis revealed that the splitting of graphene layers is efficiently taken place in GO from ball-milled graphite. The lowest optimum temperature for thermal reduction of GO to rGO was found to be at 475 °C. FTIR confirmed the removal of most of the functional groups in rGO and according to the BET surface area analysis few layers, supposed to be 2-6 is formed. The efficient oxidation and reduction process of smaller particle size graphite has led to yield highly oxidized GO and high quality rGO which can be used to prepare high quality graphene for future applications.
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Ivanov, V., and M. Matveishyn. "ANALYSIS OF THE GRAPHITE PHASE IN CENTRIFUGED BILLIONS MADE OF HIGH-QUALITY CAST IRON." New Materials and Technologies in Metallurgy and Mechanical Engineering, no. 2 (June 20, 2023): 26–31. http://dx.doi.org/10.15588/1607-6885-2023-2-4.
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Purpose. To determine the characteristic geometric parameters of spherical graphite inclusions in the cross-section of a cast iron billet for piston rings.
Research methods. A cylindrical blank for piston rings was obtained by the centrifugal method. The chemical composition of the blank according to the ВЧ 500-2 brand (DSTU 3925-99). To obtain spherical graphite, nickel-magnesium ligature (15 % Mg) and secondary graphitizing modification with ferrosilicobarium ФС65Ба4 were used. The amount of each additive was 1.0 % of the metal mass. Spherical graphite was evaluated according to GOST 3443 and several characteristic geometric parameters. A computer image analyzer based on a “ZEISS Epityp-2” microscope with a digital video camera “Baumer” was used.
Results. The geometric parameters of graphite inclusions in the cross-section of a centrifugal billet made of high-strength cast iron are examined. A significant difference in the geometric parameters of spherical inclusions of graphite according to several size groups formed in different layers of the cast iron billet obtained by centrifugal casting was established.
Scientific novelty. Spherical graphite inclusions in the oil billet are classified according to 6 size groups of GOST 3443 and 11 size groups built in arithmetic progression. Significant differences between the outer and central layers of the casting were established: 2.14 times – by the number of small (5...10 μm) inclusions; 1.59 times – by the number of inclusions with a size of 10...15 μm, 1.4 times – by the number of inclusions with a size of 20...25 μm; 3.9 times – by the number of large (more than 35 μm inclusions).
Practical value. A comparative assessment of the morphology of spherical graphite in the outer, central and inner layers of the centered workpiece will allow to improve the technological parameters of the production of cast piston rings in order to ensure a high resource of engines or compressors.
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Kadhim, Mohamed Ali, Hussain Al Ali Jalal Ghuloom, Garry Martin, and Michael Jacobs. "Aluminium Bahrain - Benefits at ALBA from Use of Improved Graphite Rings for Production of Extrusion Ingots." Materials Science Forum 630 (October 2009): 251–57. http://dx.doi.org/10.4028/www.scientific.net/msf.630.251.
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Surface quality and metallurgical characteristics of extrusion ingot have a significant impact on the extrudability of the billet. Both the type of casting mould and mould maintenance significantly influences billet surface quality. ALBA, like the majority of extrusion ingot producers, uses moulds with graphite technology, where a mix of oil and gas is injected through a graphite ring into the mould to improve billet surface quality. ALBA has a policy of continual improvement in the areas of safety, product quality and productivity to enhance customer satisfaction. During 2008, an extensive campaign was conducted in ALBA’s casthouse to select the optimum type of casting rings for Airslip™ moulds supplied by Wagstaff Inc. The graphite casting rings evaluated must be suitable for the casting conditions and environment within the casthouse at ALBA. This paper details the methodology and the criteria set for the selection of the optimum graphite casting ring type as well as the results achieved. The results of the work showed a preference for L type casting rings, which enhance the quality of the extrusion ingots and extend the service life of the graphite ring.
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PACANA, Andrzej, and Karolina CZERWIŃSKA. "ANALYSIS OF QUALITY CONTROL OF THE GRAPHITE PROCESS ON THE EXAMPLE OF A COMPANY FROM THE AUTOMOTIVE INDUSTRY." Scientific Papers of Silesian University of Technology. Organization and Management Series 2019, no. 134 (2019): 171–80. http://dx.doi.org/10.29119/1641-3466.2019.134.13.
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Moye, Charles D., and Michael M. Msabi. "Mineralogical and geochemical characteristics of graphite-bearing rocks at Chenjere Area, south-eastern Tanzania: Implications for the nature and quality of graphite mineralization." Tanzania Journal of Science 47, no. 2 (May 11, 2021): 535–51. http://dx.doi.org/10.4314/tjs.v47i2.11.
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This study focused on the mineralogical and geochemical characteristics of graphite-bearing rocks at Chenjere area by conducting surface geological mapping, geochemical and petrographical analyses with the intention of characterizing the nature of graphite occurrence in these lithological units. This paper presents results of the flake size, grade and mineralization extension of graphite in the graphitic gneiss. Field observations, petrographic investigation and comparison with other studies indicate that graphite occurrence at the Chenjere area is of sedimentary origin which fall under syngenetic type. The petrographic study revealed that nature of metamorphism of rocks in the Chenjere area is of high grade (amphibolite facies). Both field observations and petrographic studies indicate that minerals in the rock associated with graphite include quartz, feldspar (mostly K-feldspar) and biotite. Further, the mineralized zones are concordant to the rest of the lithologies of the area and biotite gneiss is forming the hangingwall and footwall. The rocks’ foliation is generally NE striking and dipping SE with the dip amount ranging from 30 to 60 degrees. The graphite mineralization at the study area occurs as medium to coarse grained crystalline, flake type graphite with long axis of up to 1000 micrometres in size. Graphite flakes are disseminated and oriented in the host rock that represents a normal metamorphic fabric. Geochemical results indicate that graphite contents in the host graphitic gneiss range from 3.03 wt.% to 16.00 wt.%. Mineralogy and texture of the graphite at Chenjere area meet the standards required for industrial applications in various advanced technologies.
Keywords: Graphite Mineralization, Flake Graphite, Chenjere Area
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Popova, O. V., A. M. Serbinovskii, and O. E. Shkurakova. "Graphite Bisulphate and Thermal Expanded Graphite from Lignin." Electrochemical Energetics 10, no. 1 (2010): 43–47. http://dx.doi.org/10.18500/1608-4039-2010-10-1-43-47.
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Pathbreaking studies of electrochemical graphite bisulphate synthesis from artificial graphite produced from hydrolyzed lignin and further production of high quality thermal expanded graphite are described. The studies show that any oxidation level can be achieved as well as over oxidized graphite may be produced at graphite bisulphate synthesis. Parameters of graphite bisulphate synthesis and thermal expanded graphite parameters are close to those of graphite bisulphate and thermal expanded graphite produced from natural graphite's. The article also describes results of microstructure and element analysis of thermal expanded graphite as well as its granulometric composition. The product is promising as a component of active masses for electrodes of chemical sources of current.
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Wieczorska, Agata, Katarzyna Panasiuk, and Sylwia Bazychowska. "Influence of Graphite as a Filler on Selected Mechanical and Structural Properties of Layered Composites with Polyester-Glass Recyclate." Journal of KONBiN 52, no. 2 (June 1, 2022): 1–22. http://dx.doi.org/10.2478/jok-2022-0011.
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Abstract The search for recycling methods of composite materials indicated the possibility of using composites with polyester-glass recyclate as structural elements. The main aim of the article was to analyse the influence of the graphite percentage content on the mechanical and structural properties of such composites. Composite materials were made by hand laminating with 10% polyester-glass recyclate and graphite nano-additive. Samples for the static tensile test were prepared, which was carried out in accordance with the applicable standard on a universal testing machine. The obtained results showed that with the increase in the amount of graphite, the properties of the composite decrease; however, disproportionately to the % of its content.
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Tran, Tuan Sang, Seung Jun Park, Sung Sic Yoo, Tae-Rin Lee, and TaeYoung Kim. "High shear-induced exfoliation of graphite into high quality graphene by Taylor–Couette flow." RSC Advances 6, no. 15 (2016): 12003–8. http://dx.doi.org/10.1039/c5ra22273g.
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A scalable method to produce high-quality graphene by shear-exfoliation of graphite is presented. High shear mixing of graphite in the Taylor vortex flow regime allows for the bulk production of few-layer graphene with low content of defects.
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Lukic, Vladimir, Milica Spasojevic, Milentije Lukovic, Miroslav Spasojevic, and Aleksa Maricic. "Hydrogen adsorption process in nanocrystalline nuclear graphite." Nuclear Technology and Radiation Protection 37, no. 1 (2022): 11–17. http://dx.doi.org/10.2298/ntrp2201011l.
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Kinetics and mechanism of hydrogen adsorption in as-obtained and ground nuclear graphite Wendelstein 7-X are examined. In the first time interval the adsorption process is determined by dissociation of the hydrogen molecule, occurring at the outer surface and in open micropores of nuclear graphite particles. However, in the second time interval, the slowest step in the hydrogen adsorption is inter-granular and inter-crystallite diffusion in nanopores of graphite. The X-ray analysis shows, that grinding of as-obtained nuclear graphite results in finer particles with finer nanocrystals and larger density of opened pores and carbon reactive sites. The capacity and rate of adsorption increase with comminution of nuclear graphite particles and adsorbed hydrogen does not substantially alter the microstructure of nuclear graphite.
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Toledo, Juan, Felipe Diaz, Matías Peralta, and Diego Fernandino. "High-quality nodule analysis in spheroidal graphite cast iron using X-ray micro-computed tomography." Frattura ed Integrità Strutturale 16, no. 62 (September 22, 2022): 279–88. http://dx.doi.org/10.3221/igf-esis.62.20.
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This work is a continuation of the studies presented in a recent paper by the authors, where a methodology to obtain different nodule quality categories in spheroidal graphite cast iron, was proposed. In this study, an exhaustive analysis of the highest-quality graphite nodules was performed. The experimental methodology involves X-ray micro-computed tomography analysis and digital image post-processing of the high-quality graphite nodule population. Furthermore, different subpopulations were selected, following a nodular size criterion. The procedure involves the evaluation and comparison of the sphericity and compactness distributions and the distances between neighbouring nodules by using ad-hoc image processing software. The results reveal the complementary nature of the sphericity and compactness parameters, which allow classifying, with great accuracy, different nodular quality categories of spheroidal graphite cast iron. Additionally, new viewpoints about the nodular morphology study and the distribution of quality nodules in the metallic matrix was provided, which could be extended to other heterogeneous materials.
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Krebbers, Leonard T., Bernd G. Lottermoser, and Xinmeng Liu. "Computed Tomography of Flake Graphite Ore: Data Acquisition and Image Processing." Minerals 13, no. 2 (February 9, 2023): 247. http://dx.doi.org/10.3390/min13020247.
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A solid knowledge of the mineralogical properties (e.g., flake size, flake size distribution, purity, shape) of graphite ores is necessary because different graphite classes have different product uses. To date, these properties are commonly examined using well-established optical microscopy (OM), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and SEM-based automated image analysis. However, these 2D methods may be subject to sampling errors and stereological effects that can adversely affect the quality of the analysis. X-ray microcomputed tomography (CT) is a nondestructive imaging technique allowing for examination of the interior and exterior of solid materials such as rocks and ores in 3D. This study aimed to explore whether CT can provide additional mineralogical information for the characterisation of graphite ores. CT was used in combination with traditional techniques (XRD, SEM-EDS, OM) to examine a flake graphite ore in 3D. A scanning protocol for the examined graphite ore was established to acquire high-quality CT data. Quantitative mineralogical information on key properties of graphite was obtained by developing a deep learning-based image processing strategy. The results demonstrate that CT allows for the 3D visualisation of graphite ores and provides valid and reliable quantitative information on the quality-determining properties that currently cannot be obtained by other analytical tools. CT allows improved assessment of graphite deposits and their beneficiation.
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Pietrowski, S. "Wearing Quality of Austenitic, Duplex Cast Steel, Gray and Spheroidal Graphite Iron." Archives of Foundry Engineering 12, no. 2 (April 1, 2012): 235–44. http://dx.doi.org/10.2478/v10266-012-0067-0.
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Wearing Quality of Austenitic, Duplex Cast Steel, Gray and Spheroidal Graphite Iron The current work presents the research results of abrasion wear and adhesive wear at rubbing and liquid friction of new austenitic, austenitic-ferritic ("duplex") cast steel and gray cast iron EN-GJL-250, spheroidal graphite iron EN-GJS-600-3, pearlitic with ledeburitic carbides and spheroidal graphite iron with ledeburitic carbides with a microstructure of the metal matrix: pearlitic, upper bainite, mixture of upper and lower bainite, martensitic with austenite, pearlitic-martensitic-bainitic-ausferritic obtained in the raw state. The wearing quality test was carried out on a specially designed and made bench. Resistance to abrasion wear was tested using sand paper P40. Resistance to adhesive wear was tested in interaction with steel C55 normalized, hardened and sulfonitrided. The liquid friction was obtained using CASTROL oil. It was stated that austenitic cast steel and "duplex" are characterized by a similar value of abrasion wear and adhesive wear at rubbing friction. The smallest decrease in mass was shown by the cast steel in interaction with the sulfonitrided steel C55. Austenitic cast steel and "duplex" in different combinations of friction pairs have a higher wear quality than gray cast iron EN-GJL-250 and spheroidal graphite iron EN-GJS-600-3. Austenitic cast steel and "duplex" are characterized by a lower wearing quality than the spheroidal graphite iron with bainitic-martensitic microstructure. In the adhesive wear test using CASTROL oil the tested cast steels and cast irons showed a small mass decrease within the range of 1÷2 mg.
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VOLCHUK, V. M., N. V. KASHYNA, M. A. KOTOV, A. M. HAIDAR, and D. O. KASHYN. "CALCULATION OF MATERIAL QUALITY CRITERIA USING FRACTAL THEORY." Physical Metallurgy and Heat Treatment of Metals, no. 2 (101) (October 21, 2023): 20–28. http://dx.doi.org/10.30838/j.pmhtm.2413.040723.20.980.
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Problem statement. Changing the parameters of standard technology can significantly change the properties of rolled iron in a wide range of values. Regulatory and technical industry documentation regulates only the hardness indicators of cast iron rolls, and the requirements for mechanical characteristics and wear resistance are not indicated due to the influence of many technological parameters. Therefore, an important aspect is the prediction for quality indicators of cast iron due to the use of mathematical modeling, in particular the theory of fractals. Materials and methods. Cast iron rolls with a pearlite matrix were studied. The mechanical properties of the working area for cast-iron graded rolled rolls produced by OJSC “Dniprovskyi zavod protnykhnykh valkov”, Dnipro, were determined on standard equipment using INSTRON and CD-40 machines, PSV 5 pendular digger, Shore hardness tester. The microstructure of the rolls was analyzed at a magnification of 200 times. The results of the experiment. As a result of the experiment, it was established that the best among analyzed sensitivity of mechanical properties to dimensional characteristics of carbides is observed for fractal, information and correlation dimensions. Therefore, it is advisable to use these dimensional estimates of carbides in the future to predict the mechanical properties of the working zone for rolled iron with lamellar graphite. To predict the mechanical properties of rolled cast iron with lamellar graphite, it is advisable to use dimensional estimates of graphite and carbides with an increase in the structure of ´200. Conclusions. The analysis of the obtained results showed the promise of using the theory of multifractals for the quantitative assessment of the structural elements of rolled cast iron rolls with a complex geometric shape. This approach makes it possible to use statistical estimates of the dimensions of graphite and carbides to predict and correct the quality indicators of roll metal according to the obtained equations (3-6) along with traditional methods of quantitative metallography, which evaluate their geometric characteristics: shape, distribution, dimensions (length, diameter) and content.
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Legkiy, N. M. "Improvement of Semiconductors Quality Using Isotopic Nanoengineering." Key Engineering Materials 854 (July 2020): 74–79. http://dx.doi.org/10.4028/www.scientific.net/kem.854.74.
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The article covers a solution of a modern electronics problem: improvement of data transmission device speed using the example of fiber-optic communication lines (FOCL). The data processing rate and throughput of transmission channels are determined by capabilities of the optoelectronics and, first of all, by the performance of its hardware components. The article presents all possible ways to improve the performance of FOCL. Design and production of communication devices moves to the nanotechnological level that opens up new possibilities for creation of semiconductors with advanced characteristics. The methods and means chosen for production of the nanostructures are crucial for creation of the new generation hardware components. Graphene is considered as the most promising material for creation of the new generation hardware components for semiconductors. Potential capabilities of the material are not yet fully explored. Isotopic nanoengineering is used as the method for production of the nanostructures with improved characteristics. In particular, we use the neutron transmutation doping technology based on irradiation of a graphite sample with a neutron flux. This method increases content of the 13C isotope (natural graphite contains only about 1.1% of this isotope). As a result, the band gap opens bringing the properties of the material closer to the properties of a semiconductor. The closer the width of the graphene band gap to the width of the silicon band gap, the closer the properties of graphene to the properties of semiconducting silicon. Furthermore, all properties of the natural graphite (high throughput and sensitivity to almost the entire optical spectrum) are preserved.
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Palosaari, J., R.-M. Latonen, J.-H. Smått, S. Raunio, and O. Eklund. "The flake graphite prospect of Piippumäki—an example of a high-quality graphite occurrence in a retrograde metamorphic terrain in Finland." Mineralium Deposita 55, no. 8 (April 8, 2020): 1647–60. http://dx.doi.org/10.1007/s00126-020-00971-z.
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Abstract The flake graphite occurrence in Piippumäki, Eastern Finland, as indicated by an airborne electromagnetic anomaly, was located during fieldwork by electromagnetic measurements with Slingram. The anomaly is approximately 0.1 × 1 km in size. The flake graphite is hosted by quartz-feldspar gneiss and amphibolite that have been subjected to retrograde metamorphism. This is observed in thin sections as granulite facies (garnet + cordierite + sillimanite + melt) regressing to greenschist facies (epidote, chlorite, albite, and white mica). The graphite (up to 1 mm large flakes) is found in graphite-bearing layers in the gneiss, and to a minor extent disseminated in the amphibolite. The average total sulfur (TS) is 0.33%, total carbon (TC) is 6.49%, and the average content of graphitic carbon (Cg) is 6.41% for the analyzed graphite-bearing rocks. SEM, XRD, and Raman spectroscopy were used for analyzing the flake graphite, indicating that the graphite is almost defect-free, of high quality, and has not been affected by the retrograde metamorphism. The peak metamorphic temperature of 737 °C was determined by a Raman thermometer, and no temperatures of greenschist facies were observed. A pseudosection was constructed from whole-rock chemical composition and indicated equilibration at ca 5 kbar and 740 °C, which corresponds to the observed mineral assemblages.
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Sun, X. J., Y. X. Li, and X. Chen. "Controlling melt quality of compacted graphite iron." Materials Science and Engineering: A 466, no. 1-2 (September 2007): 1–8. http://dx.doi.org/10.1016/j.msea.2007.05.016.
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Chaika, E. F., I. G. Maryasev, and A. A. Platonov. "Graphite. Evaluation of Quality for Refractory Industry." Refractories and Industrial Ceramics 57, no. 5 (January 2017): 449–61. http://dx.doi.org/10.1007/s11148-017-0003-5.
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Volchuk, Volodymyr, and Sergii Kroviakov. "Method of material quality estimation with usage of multifractal formalism." Tehnički glasnik 12, no. 2 (June 28, 2018): 93–97. http://dx.doi.org/10.31803/tg-20180302115027.
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Feasibility of application of multifractal theory for evaluation of materials mechanical properties, cast iron in particular, has been considered. The proposed method enables evaluation of mechanical properties of materials based on determination of their sensitivity to dimensions of structure elements from the multifractal Renyi spectrum. Sensitivity of cast iron ultimate strength to informational dimension of carbides, ultimate bending strength to fractal dimension of carbides, impact strength to correlation dimension of carbides and hardness to fractal dimension of graphite have been determined. Fractal prediction models of quality characteristics of cast iron based on the analysis of the following its structure elements (carbides and graphite) have been received.
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Wang, Xin, and Long Zhang. "Green and facile production of high-quality graphene from graphite by the combination of hydroxyl radical and electrical exfoliation." RSC Advances 8, no. 71 (2018): 40621–31. http://dx.doi.org/10.1039/c8ra07880g.
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A novel, simple and efficient method, involving the combination of hydroxyl radicals and electrical exfoliation of graphite for the green production of high-quality graphene from graphite, was developed for the first time.
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Kutyaeva, K. M., E. G. Cheblakova, Yu A. Malinina, A. A. Shvetsov, and N. Yu Beylina. "Analytical control of silicified graphite SG-P." Industrial laboratory. Diagnostics of materials 87, no. 8 (August 21, 2021): 69–75. http://dx.doi.org/10.26896/1028-6861-2021-87-8-69-75.
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An analytical scheme for the analysis of silicified graphite SG-P, a four-phase composite material consisting of silicon, carbon, silicon carbide and silicon dioxide, has been developed. The procedure can be successfully used in the quality control of raw materials and in the study of the phase composition of finished products The porosity and density of the graphite base, as well as the impurities contained in the base and silicon change the course of silicification and the properties of the finished product as well. The impurities are the main reason for the formation of delamination, swelling, cracking and light spots on the treated surfaces. It should be noted that the iron content 0.023 – 0.17 wt.% in the carbon material intended for silicification, leads to catalytic graphitization of the artificial graphite and dispersion in the silicon melt. Methods of rapid assessment of the quality of raw materials are to be used to provide quick understanding of their suitability for manufacturing final products on their base. Quality control of the silicified graphite produced at the JSC «Research Institute Graphite» is carried out by determination of the phase composition of the finished product by chemical and X-ray diffraction methods of analysis. The content of silicon carbide (not less than 45%), unbound silicon and carbon (not more than 20 and 35%, respectively) affects the corrosion resistance and thermal expansion of silicified graphite.
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Gholamalizadeh, Naghmeh, Saeedeh Mazinani, Majid Abdouss, Ali Mohammad Bazargan, and Fataneh Fatemi. "Efficient and Direct Exfoliation of High-Quality Graphene Layers in Water from Different Graphite Sources and Its Electrical Characterization." Nano 16, no. 07 (June 24, 2021): 2150079. http://dx.doi.org/10.1142/s179329202150079x.
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Green and efficient mass production of graphene sheets with high quality and electrical conductivity is intriguing for both academic scientists and industry. Among numerous production methods suffering from complexity or harsh chemical media, direct and high-yield exfoliation of graphite in water seems to be the best choice. In this study, efforts were made to prepare high-quality and stable graphene dispersions with the highest possible concentrations through an ultrasound-assisted liquid-phase exfoliation (LPE) in water directly from two types of natural graphites. The rigorous structural, morphological and electrical analyses were conducted on both graphite and graphene samples to quantitatively identify the effect of graphite sources on the LPE yield and the quality of the graphene nanosheets produced in the presence of an ionic surfactant. The results obtained by TEM, AFM, XRD and Raman spectroscopy indicated the successful and efficient production of single and few layer graphene sheets with the remarkable concentration of 3.18[Formula: see text]mg.ml[Formula: see text] in water. Moreover, the results signified that the structural quality, electrical conductivity and production yield of the graphene layers undoubtedly depend on the structural properties of graphite source. In fact, the graphite source greatly influences the final properties and potential applications of the produced graphene layer and the results are so important for the future graphene industry.
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Sułkowski, B., G. Boczkal, P. Pałka, and G. Mrówka-Nowotnik. "Effect of graphite microstructure on their physical parameters and wettability properties." NOVYE OGNEUPORY (NEW REFRACTORIES), no. 8 (November 24, 2021): 34–39. http://dx.doi.org/10.17073/1683-4518-2021-8-34-39.
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To produce castings of titanium, nickel, zinc, copper and many other metal alloys, graphite molds can be used. Using graphite molds has many advantages which are no lubricate or coating layers are needed, high cooling rate, easy of production of complicated shapes. However, for good quality of castings there is needed a good quality of graphite with high mechanical properties and good heat transfer coefficient. Because of no room for manipulating of chemical composite of graphite molds, the most important factor influencing the properties of the molds is their production process. Thus, in the present study mechanical properties of two different type of graphite were investigated. There was graphite produced by different technological processes. One of the processes was a typical graphite production process from the isotropic coke, the second process was an electrolytic method production. Investigations included mechanical tests as well as the structure observations by scanning electron microscope. Chemical analysis was determined by Energy Dispersive X-ray Spectroscopy method additionally, phase analysis using the XRD method was performed. Mechanical properties were obtained by compression tests and three points banding tests at room temperature. It was found that the porosity of a graphite is the key parameter for good its mechanical properties. In addition, it was found that the mechanical anisotropy of graphite is the effect of the production method where the size and distribution of pores play an important role. Ill. 7. Ref. 9.
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He, Peng, Chao Zhou, Suyun Tian, Jing Sun, Siwei Yang, Guqiao Ding, Xiaoming Xie, and Mianheng Jiang. "Urea-assisted aqueous exfoliation of graphite for obtaining high-quality graphene." Chemical Communications 51, no. 22 (2015): 4651–54. http://dx.doi.org/10.1039/c5cc00059a.
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Hishiyama, Y., Y. Kaburagi, and Masahiko Inagaki. "Synthesis of High Quality Graphite Films. New Host Materials for Graphite Intercalation Compounds." Materials Science Forum 91-93 (January 1992): 239–43. http://dx.doi.org/10.4028/www.scientific.net/msf.91-93.239.
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Vershinin, A. V., M. V. Vershinina, E. G. Belyakova, E. V. Polyakov, V. G. Bamburov, and I. V. Volkov. "Investigation of impurities detected in X-ray inspection of MPG-7 fine-grained graphite blanks and details." Journal of «Almaz – Antey» Air and Space Defence Corporation, no. 4 (December 30, 2017): 80–85. http://dx.doi.org/10.38013/2542-0542-2017-4-80-85.
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The purpose of the research was to study the structure of MPG-7 fine-grained graphite by X-ray inspection and scanning electron microscope investigation methods. We carried out a structural and local chemical analysis of inhomogeneities occurring in graphite blanks. According to the data obtained, we changed technical documentation for the incoming quality control of MPG-7 graphite blanks and details.
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Snopkov, S. V., A. V. Khobta, and I. A. Bogdanova. "History of discovery of the Botogol graphite deposit. Myths and facts." Geology and Environment 2, no. 1 (2022): 154–65. http://dx.doi.org/10.26516/2541-9641.2022.1.154.
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The Botogol graphite mine, located in the Oka district of the Republic of Buryatia, was one of the first mining enterprises of the Baikal region. History of the discovery and development of the Botogol graphite deposit has not only many "white spots", but also widespread myths. The article provides data on discovery and initial stage of development of a high-quality graphite deposit.
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Stawarz, Marcin, and Malwina Dojka. "Bifilm Inclusions in High Alloyed Cast Iron." Materials 14, no. 11 (June 4, 2021): 3067. http://dx.doi.org/10.3390/ma14113067.
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Continuous improvement in the quality of castings is especially important since a cast without defects is a more competitive product due to its longer lifecycle and cheaper operation. Producing quality castings requires comprehensive knowledge of their production, crystallization process, and chemical composition. The crystallization of alloyed ductile iron (without the addition of magnesium) with oxide bifilm inclusions is discussed. These inclusions reduce the quality of the castings, but they are a catalyst for the growth of spheroidal graphite that crystallizes in their vicinity. The research was carried out for cast iron with a highly hyper-eutectic composition. Scanning electron microscopy and EDS analysis were used in the research. A detailed analysis of the chemical composition was also carried out based on the spectrometric method, weight method, etc. Based on the obtained results, a model of spheroidal graphite crystallization near bifilm inclusions was proposed. The surface of the analyzed graphite particles was smooth, which suggests a primary crystallization process. The phenomenon of simple graphite and bifilm segregation towards the heat center of the castings was also documented.