Literatura científica selecionada sobre o tema "Additif conducteur"
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Artigos de revistas sobre o assunto "Additif conducteur"
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Seppälä, Arja, Yolanda Madrid Albarran, Harri Miettinen, Maria Palomo Siguero, Elina Juutinen e Marketta Rinne. "Selenium supplementation by addition of sodium selenate with silage additive". Agricultural and Food Science 23, n.º 2 (1 de julho de 2014): 81–88. http://dx.doi.org/10.23986/afsci.41179.
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An ensiling experiment was conducted to assess the possibility for increasing the selenium content in grass silage by using a selenium-enriched silage additive, and to determine possible changes in the form of selenium during ensiling. Prewilted and precision-chopped silage was prepared from the second cut of timothy – meadow fescue sward in southern Finland. The additive treatments (6 g kg-1) were: control without additive, water containing 50 mg sodium selenate kg-1, and formic acid-based additive containing 10, 50 or 500 mg sodium selenate kg-1. The selenium content of the control silage was low (0.069 mg kg-1 dry matter) whereas the selenium content of the other silages was in line with the dose level of selenium delivered in the additive. The added selenate was detected only as selenate in the silages. Addition of sodium selenate to silage additive provided a controlled way to add selenium to the diet of forage-fed animals.
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De Smedt, Ronald. "Addition to “DC Internal Inductance for a Conductor of Rectangular Cross Section”". IEEE Transactions on Electromagnetic Compatibility 51, n.º 3 (agosto de 2009): 875–76. http://dx.doi.org/10.1109/temc.2009.2027126.
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Itoh, Kenzo. "An additive blending sound presentation system with air and bone conducted sound". Journal of the Acoustical Society of America 130, n.º 4 (outubro de 2011): 2449. http://dx.doi.org/10.1121/1.3654834.
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Wang, Yanzhong, Anthony Chesnaud, Emile Bevillon, Jinlong Yang e Guilhem Dezanneau. "Influence of ZnO additive on the properties of Y-doped BaSnO3 proton conductor". Materials Science and Engineering: B 176, n.º 15 (setembro de 2011): 1178–83. http://dx.doi.org/10.1016/j.mseb.2011.06.009.
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Kovacevic, Aleksandar, Dejan Despotovic, Zoran Rajovic, Koviljka Stankovic, Ana Kovacevic e Uros Kovacevic. "Uncertainty evaluation of the conducted emission measurements". Nuclear Technology and Radiation Protection 28, n.º 2 (2013): 182–90. http://dx.doi.org/10.2298/ntrp1302182k.
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For the evaluation of measurement uncertainty in measuring the conduction emission, in this paper we propose a new model which uses mixed distribution. Evaluation of probability density function for the measurand has been done using Monte Carlo method and a modified least-squares method (combined method). In addition, the number of data n and the number of classes of histogram k which were used for simulation, were varied.
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Huber, Sebastian, e Arno Pfitzner. "Li17Sb13S28: A New Lithium Ion Conductor and addition to the Phase Diagram Li2S-Sb2S3". Chemistry - A European Journal 21, n.º 39 (11 de agosto de 2015): 13683–88. http://dx.doi.org/10.1002/chem.201502052.
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Wang, Qingfu, Pingping Liu, Shizhen Li, Xiao Wang, Fangzhou Li, Jun Ma, Jingchao Chai et al. "A Flame Retardant Ionic Conductor Additive for Safety-Reinforced Liquid Electrolyte of Lithium Batteries". Journal of The Electrochemical Society 164, n.º 7 (2017): A1559—A1563. http://dx.doi.org/10.1149/2.1111707jes.
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Zhang, Jiayi, e Wei Wang. "Corrosion Behaviour Between Al–Zr Alloy Conductor and Cu Transition Terminal via Sc Addition". Chemistry Africa 3, n.º 2 (16 de janeiro de 2020): 317–21. http://dx.doi.org/10.1007/s42250-020-00118-7.
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Shimizu, Takashi, Masaya Kokufuda, Yusaku Hirano e Yoshinori Kogami. "Effective Conductivity Measurements for Additive Manufacturing Technology Conductor using Two Dielectric Rod Resonator Method". IEEJ Transactions on Electronics, Information and Systems 141, n.º 8 (1 de agosto de 2021): 915–16. http://dx.doi.org/10.1541/ieejeiss.141.915.
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Dora, Kim A., Jun Xia e Brian R. Duling. "Endothelial cell signaling during conducted vasomotor responses". American Journal of Physiology-Heart and Circulatory Physiology 285, n.º 1 (julho de 2003): H119—H126. http://dx.doi.org/10.1152/ajpheart.00643.2002.
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ACh and KCl stimulate vasomotor responses that spread rapidly and bidirectionally along arteriole walls, most likely via spread of electric current or Ca2+ through gap junctions. We examined these possibilities with isolated, cannulated, and perfused hamster cheek pouch arterioles (50- to 80-μm resting diameter). After intraluminal loading of 2 μM fluo 3 to measure Ca2+ or 1 μM di-8-ANEPPS to measure membrane potential, photometric techniques were used to selectively measure changes in intracellular Ca2+ concentration ([Ca2+]i) or membrane potential in endothelial cells. Activation of the endothelium by micropipette application of ACh (10-4 M, 1.0-s pulse) to a short segment of arteriole (100–200 μm) increased endothelial cell [Ca2+]i and caused hyperpolarization at the site of stimulation. This response was followed rapidly by vasodilation of the entire arteriole (∼2-mm length). Change in membrane potential always preceded dilation, both at the site of stimulation and at distant sites along the arteriole. In contrast, an increase in endothelial cell [Ca2+]i was observed only at the application site. Micropipette application of KCl, which can depolarize both smooth muscle and endothelial cells (250 mM, 2.5-s pulse), also caused a rapid, spreading response consisting of depolarization followed by vasoconstriction. With KCl stimulation, in addition to changes in membrane potential, increases in endothelial cell [Ca2+]i were observed at distant sites not directly exposed to KCl. The rapid longitudinal spread of both hyperpolarizing and depolarizing responses support electrical coupling as the mode of signal transmission along the arteriolar length. In addition, the relatively short distance between heterologous cell types enables the superimposed radial Ca2+ signaling between smooth muscle and endothelial cells to modulate vasomotor responses.
Teses / dissertações sobre o assunto "Additif conducteur"
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Tronel, Frédéric. "De nouveaux additifs conducteurs à base de cobalt pour l'électrode positive des accumulaterus Ni-MH". Bordeaux 1, 2003. http://www.theses.fr/2003BOR12750.
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Dans le premier volet de l'étude, des matériaux à base de cobalt ont été synthétisés par oxydation électrochimique à 90°C de Co(OH)2 dans différents électrolytes alcalins concentrés (KOH, NaOH, LiOH), afin de reproduire ex-situ l'effet du procédé de "formation à chaud" sur les phases au cobalt ajoutées à l'électrode positive des accumulateurs Ni-MH. Ces matériaux ont été caractérisés par diffraction des rayons X et des neutrons, RMN MAS du 7Li et par des mesures électriques. Une phase, de structure spinelle et de conductivité élevée, obtenue en présence de lithium a pu être isolée. Cette phase, proche de Co3O4, se distingue par des lacunes en cobalt, la présence simultanée de lithium et d'ions Co4+ au sein de sa structure. Par ailleurs, l'étude du mécanisme de formation de cette phase a permis d'établir que ce type de phase spinelle se formait par réaction entre une phase lamellaire CoOOH formée par oxydation électrochimique de Co(OH)2 et du cobalt passé en solution dans l'électrolyte. Dans le second volet, la possibilité d'utiliser la phase Na0,60CoO2 comme additif conducteur a été démontrée. De plus, il a été observé que cette phase permet de prévenir les pertes de capacité de l'électrode positive en stockage à bas potentiel. Des études in-situ ont aussi permis d'observer que la phase au cobalt active au sein de l'électrode après quelques cycles est un oxyhydroxyde de cobalt de type γ en lequel la phase Na0,60CoO2 se transforme progressivement.
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Butel, Maurice. "Etude de nouveaux oxyhydroxydes de cobalt pouvant être utilisés comme additif conducteur électronique ajoutés à l'hydroxyde de nickel dans les accumulateurs nickel/cadmium et nickel/métal hydrure". Phd thesis, Université Sciences et Technologies - Bordeaux I, 1998. http://tel.archives-ouvertes.fr/tel-00133167.
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La tres faible conductivite electronique de l' hydroxyde de nickel utilise a l' electrode positive de l' accumulateur nickel - cadmium rend necessaire l' ajout d' un conducteur electronique. Actuellement, les fabricants d' accumulateurs ont recours a l' addition de phases cobaltees pour ameliorer les performances de l' electrode de nickel. Ce travail est donc consacre a l' etude des differentes especes chimiques et des mecanismes impliques lors de l' utilisation d' un oxyde de cobalt du type CoO comme conducteur electronique ajoute a l' electrode positive d' une batterie nickel-cadmium. La premiere partie est relative a la caracterisation physico-chimique des phases responsables de la conduction electronique au sein de l' electrode de nickel (oxyhydroxydes de cobalt) : etude structurale par la methode de Rietveld, determination de la formulation chimique et analyse des proprietes de conduction electronique. Une etude electrochimique de ces materiaux a egalement ete effectuee a l' aide des techniques de cyclages voltamperotrique et galvanostatique. La seconde partie est relative a l' etude des mecanismes reactionnels conduisant du monoxyde de cobalt a l' oxyhydroxyde de cobalt.
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Lambert, Romain. "Nouveaux copolymères et nanostructures dérivés de liquides ioniques à base d'imidazoliums : applications en catalyse et comme additifs conducteurs ioniques". Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0306/document.
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Des poly(liquides ioniques) (PILs) arrangés sous la forme de copolymères statistiques,de nanoparticules à chaine unique ou bien sous la forme de copolymères à blocs autoassemblés ont été employés comme précurseurs de carbènes N-hétérocycliques (NHC)s à des fins de catalyses organiques ou organométalliques. L’introduction d’anions acétate dans des unités PIL dérivés d’imidazolium permet la génération in situ de NHCs actifs en catalyse. Les nanoparticules composées d’une chaine unique polymère repliée sur elle-même (SCNP) ont été spécialement conçues selon deux stratégies impliquant, d’une part, une réaction d’autoquaternisation entre groupements fonctionnels antagonistes portés par la chaine et, d’autre part, une réaction de complexation organométallique à l’aide d’un sel de palladium. Dans lesdeux cas, les chaines polymères ont été obtenues par polymérisation contrôlée (méthode RAFT). Les copolymères à blocs amphiphiles comportant un bloc PIL fonctionnalisé par du palladium ont été synthétisés par polymérisation RAFT et auto-assemblés dans l’eau sous forme de micelles.Un effet de confinement des sites catalytiques a clairement été démontré à travers des réactions de catalyse pour les couplages de Suzuki et de Heck dans l’eau, avec un gain cinétique très net par rapport à des homologues non micellisés, en plus d’une grande facilité de recyclage de ces supports micellaires.Enfin, des copolymères à blocs à base de PIL-benzimidazolium à contre anion bis(trifluoromethane)-sulfonylimide de lithium ont été développés comme agents dopants conducteurs ioniques de matrices structurantes PS-b-PEO. Des mélanges configurés en films minces avec une quantité minimale d’agent dopant ont conduit dans certaines conditions à des valeurs optimales de conductivité ionique grâce à une nano structuration des films à longue distancePoly(ionic liquid)s (PILs) in the form of random copolymers, single chain nanoparticles(SCNPs), or self assembled block copolymers have been used as N-heterocyclic carbenes(NHCs) precursors for the purpose of organic and organometallic catalysis. Introducing acetate derivative counter anion in imidazolium based PIL units enable in situ generation of catalyticallyactive NHC. SCNPs have been specially designed along two strategies including, firstly, a self quaternization reaction involving two antagonists groups supported on to the polymer chain and,secondly, an organometallic complexation featuring palladium salt. Both polymeric precursors were obtained using RAFT as controlled polymerization method. Amphiphilic block copolymers composed of a PIL block functionalized by palladium have been synthesized by RAFT and self-assembled in water, leading to micellar structures. Confinement effect has been demonstrated through Suzuki and Heck coupling in water showing kinetic gain compared to molecular homologue in addition to an easier recycling method.Finally, PIL-benzimidazolium based block copolymers with lithium bis(trifluoromethane)-sulfonylimide anion have been developed as ionic conductor doping agent for PS-PEO matrix. Thin films blends with minimum doping agent amount led to optimum ionic conductivity owing tolong range order
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Douin, Myriam. "Etude de phases spinelle cobaltées et d'oxydes lamellaires dérivés de Na0,6CoO2 employés comme additifs conducteurs dans les accumulateurs Ni-MH". Bordeaux 1, 2008. http://www.theses.fr/2008BOR13562.
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La technologie mousse utilisée actuellement pour la conception des électrodes positives des batteries Ni-MH, nécessite l'emploi d'un additif conducteur au cobalt en raison de la mauvaise conductivité électronique de la matière active Ni(OH)2. La recherche de nouveaux composés au cobalt constitue un point clé en vue du développement de ces batteries vers des applications de forte puissance. Dans ce contexte, deux additifs conducteurs potentiels ont été étudiés au cours de ces travaux de thèse. La première partie de l'étude a été focalisée sur des phases spinelle HxLiyCo3-8O4 conductrices, synthètisées par oxydation électrochimique de l'oxyde CoO. Une forte influence du traitement thermique du matériau sur sa conductivité électronique a été mise en évidence. Des analyses par diffraction des rayons X in situ, ATG-SM, RMN et des mesures de conductivités électroniques ont permis de mettre en évidence une redistribution catonique au sein de la structure spinelle, conduisant à une augmentation du rapport atomique Co4+/Co3+ dans le réseau octaédrique [Co2O4], sans variation du degré d'oxydation moyen du cobalt. Il s'ensuit une augmentation de la conductivité elctronique du matériau de trois ordres de grandeur. Le second axe de la thèse concerne l'étude du comportement électrochimique de l'additif Na0,6CoO2. Les réactions échange/insertion des ions alcalins mises en jeu au cours des processus d'oxydation et de réduction de la phase initiale ont été étudiées en détail et un mécanisme a pu être proposé. L'oxyhydroxyde de cobalt hydraté γ, formé par oxydation de Na0,6CoO2 au cours du cyclage, s'est avéré présenter de très bonnes performances lors de tests en batteries. La formation d'une phase interstratifiée intermédiaire, qui possède une cinétique de réduction lente, permet de conserver la stabilité de l'additif à bas potentiel et par conséquent, l'intégralité du réseau conducteur.
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Guimont, Aline. "Greffage de polydimethylsiloxane et de polyéthylène sur des feuillets de graphène oxydé : application à la synthèse de (nano)composites conducteurs". Thesis, Lyon 1, 2013. http://www.theses.fr/2013LYO10028/document.
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L'objectif de la thèse est d'expérimenter et de valider de nouvelles voies d'exfoliation des feuillets de graphène dans des élastomères de type silicone (PDMS) et des thermoplastiques de type polyéthylène (PE). Ce projet s'appuie sur des étapes de modifications chimiques des feuillets de graphite oxydé (GO) dont la polarité initiale n'offre pas une compatibilité satisfaisante avec les matrices étudiées. Différentes approches ont été explorées : la synthèse du GO greffé PDMS a été réalisée avec succès par greffage directe d'un PDMS fonctionnalisé triéthoxysilane et par une réaction d'hydrosilylation catalytique de GO modifiés vinyltriméthoxysilane en présence de polyméthylhydrogénosiloxane. Une étude des propriétés viscoélastiques de suspensions de GO et GO modifié/PDMS a montré l'importance de l'interaction charge-charge sur la formation d'un réseau percolant. Le seuil de percolation rhéologique du GO a été obtenu à 1,75 %wt avec Af~60. En se basant sur le greffage radicalaire du pentadécane par abstraction d'atomes d'H par un peroxyde à haute température, il a été possible d'extrapoler cette réaction pour procéder au greffage d'un PE de faible masse molaire (Mn~2000). De plus, des PE fonctionnalisés thiol et azoture de Mn similaire ont aussi été greffés sur des dérivés du graphite par addition radicalaire et de Michael. Après sélection d'une charge présentant une conductivité en poudre proche du graphite et une bonne affinité pour les milieux alcanes, un nano-composite à base de PEBD présentant des propriétés électriques convenables pour une application de blindage électromagnétique (4.105 Ω.cm à 25%wt) a été réalisé et ceci sans utiliser d'agents réducteurs toxiquesThe aim of this thesis was to experiment and validate new means of graphene exfoliation in an elastomer matrix such as silicone (PDMS) and a thermoplastic matrix such as polyethylene (PE). Because of the low affinity of graphene oxide for these matrices due to its high polarity, its chemical modification was carried out. Different approaches were explored: the grafting of PDMS onto GO was carried out with success by a direct functionalization with a PDMS terminated triethoxysilane and by a catalytic hydrosilation reaction of a PDMS terminated Si-H onto vinyltrimethoxysilane modified GO. The viscoelastic behavior of GO and modified GO/PDMS suspensions showed the importance of the filler-filler interaction on the formation of a percolating network. The rheological percolation threshold of the GO/PDMS suspension was obtained at ~1.75 wt% with an aspect ratio (Af) of ~60. In addition, the grafting of PE onto GO was studied with the high temperature radical grafting of pentadecane formed by a hydrogen atom abstraction with a peroxide, which was then extrapolated to a low molecular PE (Mn~2000). Moreover, thio and azide functionnalized PE with a similar Mn were also grafted onto graphite derivatives by a radical and a Michael addition. After choosing the filler which presented the closest electrical conductivity to the one of graphite powder and a good affinity for a heptane media, a LDPE based nano-composite that presented suitable electrical properties for an electromagnetic shielding application (4 105 Ω.cm at 25 wt%) was obtained and this without any use of toxic reducing agents
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Douin, Myriam. "Etude de phases spinelle cobaltée et d'oxydes lamellaires dérivés de Na0,6CoO2 employés comme additifs conducteurs dans les accumulateurs Ni-MH". Phd thesis, Université Sciences et Technologies - Bordeaux I, 2008. http://tel.archives-ouvertes.fr/tel-00373899.
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La technologie mousse utilisée actuellement pour la conception des électrodes positives des batteries Ni-MH, nécessite l'emploi d'un additif conducteur au cobalt en raison de la mauvaise conductivité électronique de la matière active Ni(OH)2. La recherche de nouveaux composés au cobalt constitue un point clé en vue du développement de ces batteries vers des applications de forte puissance. Dans ce contexte, deux additifs conducteurs potentiels ont été étudiés au cours de ces travaux de thèse.La première partie de l'étude a été focalisée sur des phases spinelle HxLiyCo3-δO4 conductrices, synthétisées par oxydation électrochimique de l'oxyde CoO. Une forte influence du traitement thermique du matériau sur sa conductivité électronique a été mise en évidence. Des analyses par diffraction des rayons X in situ, ATG-SM, RMN et des mesures de conductivités électroniques ont permis de mettre en évidence une redistribution cationique au sein de la structure spinelle, conduisant à une augmentation du rapport atomique Co4+/Co3+ dans le réseau octaédrique [Co2O4], sans variation du degré d'oxydation moyen du cobalt. Il s'ensuit une augmentation de la conductivité électronique du matériau de trois ordres de grandeur. Le second axe de la thèse concerne l'étude du comportement électrochimique de l'additif Na0.6CoO2. Les réactions d'échange/insertion des ions alcalins mises en jeu au cours des processus d'oxydation et de réduction de la phase initiale ont été étudiées en détail et un mécanisme a pu être proposé. L'oxyhydroxyde de cobalt hydraté γ, formé par oxydation de Na0.6CoO2 au cours du cyclage, s'est avéré présenter de très bonnes performances lors des tests en batteries. La formation d'une phase interstratifiée intermédiaire, qui possède une cinétique de réduction lente, permet de conserver la stabilité de l'additif à bas potentiel et par conséquent, l'intégrité du réseau conducteur.
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Vongsaysy, Uyxing. "Studies on processing additives introduced to increase the efficiency of organic solar cells : selection and mechanistic effects". Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0230/document.
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Les cellules solaires organiques à hétérojonction en volume (BHJ en anglais) font l'objet d'un grand intérêt car elles représentent une source d'énergie bon marché et renouvelable. Cependant, à cause des rendements généralement bas, ce type de cellule peine à intégrer le marché. Afin d’en augmenter le rendement, contrôler la morphologie des semi-conducteurs dans la BHJ représente un élément clé. Dans ce contexte, il apparaît, dans la littérature, que les additifs solvant permettent de contrôler cette morphologie et d'augmenter les rendements.Cette thèse a pour but de fournir une étude complète sur l'utilisation des additifs. Le couple de semi-conducteurs étudié est le poly(3-hexylthiophene) (P3HT)/[6,6]-phényl-C61butanoate de méthyle (PC61BM).Une première partie présente une méthode développée pour guider la sélection d'additifs parmi une liste de solvants. Cette méthode emploie les paramètres de solubilité de Hansen des semi-conducteurs. Elle est appliquée au système P3HT/PC61BM et résulte en l'identification de trois nouveaux additifs performants. Ensuite, des caractérisations structurales, électriques et optiques sont menées sur la BHJ et permettent d'identifier les effets des additifs. Les effets de ces additifs se révèlent être différents en fonction de l'architecture des dispositifs. L'origine de telles différences est corrélée aux variations de mobilités des porteurs de charge causées par les additifs. Des tests de photo-stabilité ont été menés et montrent que les additifs sont capables d'augmenter la stabilité des cellules solaires. L’origine de telles améliorations est étudiée. Enfin, l'étude est étendue à deux autres nouveaux polymères semi-conducteursPolymeric bulk heterojunction (BHJ) organic solar cells (OSCs) have attracted significant interest as a low cost and renewable technology to harvest solar energy. However, their generally low efficiencies are a barrier for their movement into commercial application. Controlling the BHJ morphology is a key step in the pursuit of higher OSC efficiencies. Processing additives have emerged as effective components for optimizing the BHJ morphology. This thesis provides a comprehensive study on the introduction of additives in the formulation of semiconductors. The semiconductor system studied is based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PC61 BM). First, a method was developed to guide the selection of additives from a large range of solvents. This method employs the Hansen solubility parameters of the semiconductors and was successfully applied to the P3HT/PC61 BMsystem. It resulted in the identification of three new efficient additives. Next, the mechanistic role of additives in influencing the BHJ morphology is investigated by performing structural, electrical and optical characterizations. Also, the effect of additives on OSC performance was found to depend on the type of the OSC architecture. Such differences were correlated to the variations in charge carrier mobilities caused by the additive. Furthermore, photo-stability tests, performed on different types of OSCs, showed that processing additives can improve the photo-stability. The origin of such improvement is investigated. Finally, the scope of this study is extended to two other donor semiconducting polymers
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REGNAULT, DU MOTTIER CHRISTINE. "Recherche de materiaux organiques dans le domaine des bis (selenopyrannylidenes) - 4:4' : conducteurs organiques et proprietes mesomorphes". Caen, 1985. http://www.theses.fr/1985CAEN2036.
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Onze bis (selenopyrannylidenes)-4 :4' ont ete synthetises par duplication de selenopyrannethiones-4 ou de perchlorates de selenopyrylium. Des analyses microscopiques, thermodifferentielles, structurales ont indique que certains perchlorates de selenopyrylium sont des smectiques a alors que les bis (selenopyrannylidenes)-4 : 4' correspondants ne semblent presenter que des phases de type cristal plastique. L'etude cristallographique et des potentiels d'ionisation et d'oxydo-reduction a montre leur interet comme donneurs d'electrons pi dans des conducteurs organiques. Des complexes a transfert de charge avec le tcnq et la ddq et des sels d'ions radicaux avec l'iode et divers contre-ions ont ete obtenus et etudies du point de vue de leurs proprietes structurales, electriques, optiques et magnetiques. Certains d'entre eux possedent un caractere metallique
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Filimonenkov, Ivan. "Electrocatalyse de la réduction de l’oxygène et de l’oxydation de l’eau par des oxydes de métaux de transition : cas des pérovskites de Mn et Co". Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAF072.
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L’étude de l'électrocatalyse des réactions de réduction de l'oxygène (RRO) et de dégagement de l'oxygène (RDO) est étroitement reliée au développement de matériaux cathodiques et anodiques pour les piles à combustible et les électrolyseurs. L’objectif de cette thèse est de développer et d’étudier des matériaux d’électrodes à base d’oxydes de Mn et de Co, actifs et stables, à la fois pour la RRO et la RDO. Les relations entre les caractéristiques électrochimiques des compositions pérovskite / carbone et les propriétés de leurs composants sont établies et étayées expérimentalement dans la thèse. Il a été constaté que la résistance des matériaux carbonés à la corrosion dans les conditions de la RDO est influencée non seulement par leur ordre cristallin, mais également par leur activité intrinsèque pour la RDO. Il a été démontré que les activités des pérovskites à base de Mn et de Co dépendent linéairement du nombre de cations de Mn et de Co rechargeables, respectivement pour la RRO et la RDO. Il a été découvert qu'une intercalation réversible de l'oxygène dans la structure cristalline des pérovskites à base de Co se produit dans les conditions de la RDO, ainsi qu'à des potentiels plus faiblesA study of electrocatalysis of oxygen reduction (ORR) and oxygen evolution (OER) reactions is closely related with a development of cathodic and anodic materials for fuel cells and elec-trolyzers. An objective of this thesis is to develop and investigate Mn, Co-oxide-based elec-trode materials active and stable in both the ORR and OER. Relationships between electro-chemical characteristics of perovskite/carbon compositions and properties of their compo-nents are stated and experimentally substantiated in the thesis. It is found a corrosion re-sistance of carbon materials under OER conditions is influenced not only by their crystalline order, but also by their intrinsic OER activity. It is shown the ORR and OER activity of Mn, Co-based perovskites linearly depends on the number of rechargeable Mn and Co cations, respectively. It is revealed a reversible oxygen intercalation through a crystal structure of Co-based perovskites occurs under OER conditions as well as at lower potentials
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Johansson, Martin. "Hårdgörning av Asp". Thesis, Växjö University, School of Technology and Design, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:vxu:diva-2291.
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Hårdgörning av trä syftar till att göra materialet hårdare. Detta går att åstadkomma genom komprimering, det komprimerade materialet tenderar dock att återgå mot sin ursprungsform då materialet utsätts för fukt om ingen låsning sker. Låsningen kan ske mekaniskt i en treskiktskonstruktion som motverkar träets fuktrörelser. Dessa skivor har dock visat sig vara instabila och tidigare försök har uppvisat deformationer i form av kupning. Denna undersökning syftar till att utreda förutsättningarna för att använda komprimerad asp samt att ta fram underlag för framtagning av en kommersiell produkt.
Praktiska tester har genomförts för att studera hårdhet, återfjädring och densitet hos det komprimerade virket. Vidare har treskiktsskivor tagits fram för att testa om det går att få en stabil konstruktion genom att variera tjockleken på spärrskiktet. Även skillnader i acklimatiseringstid och fuktkvotens inverkan för virkets återfjädring har studerats.
Resultaten visar på att aspens hårdhet efter komprimering blir i samma nivå som bok och ask, en låg fuktkkvot vid komprimering av materialet ger en låg återfjädring, komprimerat material har en längre acklimatiseringstid till jämviktsfuktkvot och materialet går att låsa tvärs fiberriktningen i en treskiktskonstruktion.
To make wood harder it can be densified. This can be achieved by compression, the compressed material tends to return to the original shape when it is exposed to moisture fluxations and if no form of fixation occurs. The fixation can be done mechanically in a three-layer panel construction which reduce movements in the timber. These panels have been found to be unstable and previous attempts have shown deformations in form of cupping. This study aims to evaluate the conditions for using compressed aspen wood, and to provide a basis for development of a commercial product.
Practical tests have been conducted to study hardness, springback and density of the compressed wood. In addition, three-layer panels have been developed to test whether it is possible to have a stable construction by varying the thickness of the buttom layer. Differences in acclimatisation time and the moisture contents effect on the springback has aslo been studied.
The results show that the hardness of aspen wood after compression is in equal levels with beech and ashes, a low moisture contet provides a low springback, compressed timber have a longer time for acclimatisation and it is possible to fixate the material in the direction across the grain in a three-layer panel construction.
Livros sobre o assunto "Additif conducteur"
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Petrantoni, Giuseppe. Corpus of Nabataean Aramaic-Greek Inscriptions. Venice: Fondazione Università Ca’ Foscari, 2021. http://dx.doi.org/10.30687/978-88-6969-507-0.
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The impact of the Hellenization in the Ancient Near East resulted in a notable presence of Greek koiné language and culture and in the interaction between Greek and Nabataean that conducted inhabitants to engrave inscriptions in public spaces using one of the two languages or both. In this questionably ‘diglossic’ situation, a significant number of Nabataean-Greek inscriptions emerged, showing that the koin was employed by the Nabataeans as a sign of Hellenistic cultural affinity. This book offers a linguistic and philological analysis of fifty-one Nabataean-Greek epigraphic evidences existing in northern Arabia, Near East and Aegean Sea, dating from the first century BCE to the third-fourth century CE. This collection is an analysis of the linguistic contact between Nabataean and Greek in the light of the modalities of social, religious and linguistic exchanges. In addition, the investigation of onomastics (mainly the Nabataean names transcribed in Greek script) might allow us to know more about the Nabataean phonological system.
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Crespellani, Teresa, ed. Terremoto e ricerca. Florence: Firenze University Press, 2008. http://dx.doi.org/10.36253/978-88-8453-819-2.
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The profound cultural transformation that has taken place in Italian seismic studies in the last ten years is distinguished by the growing interest in the problem of assessing the effects of earthquakes linked to local conditions, and in the related issue of a precise definition of the properties of the soil in the sphere of the dynamic and cyclical stresses induced by seismic actions. Despite the profound awareness of the extent to which the nature of the soil contributes to the destructive effects of earthquakes, we are still a long way from the possibility of a realistic forecast of the seismic behaviour of the Italian soils. This is because the identification of the dynamic properties calls for experimental equipment that is technologically complex and costly as well as lengthy observation and qualified personnel. The rare experimental data that have been acquired to date hence represent a fundamental element for scientific reflection. This book has been conceived with a view to setting at the disposal of a broader public the results of the tests conducted on site and in the laboratory on the soil of certain significant seismic areas using the dynamic-type apparatus of the Geotechnical Laboratory of the Department of Civil and Environmental Engineering (DICeA) of the University of Florence. It presents a selection of the works of the Geotechnical section of the DICeA that have been published in various specialist international and national ambits. These studies were largely launched following the seismic sequence in Umbria and the Marches, in collaboration with several Regional Authorities and Research Institutes for the reduction of the seismic risk in Italy (GNDT, IRRS, INGV). In addition to the experimental techniques and the results obtained, the models and the geotechnical procedures adopted for assessing the effects of site and soil instability in certain specific deposits of the Italian territory are also expounded.
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Abdelmoneium, Azza, Asma Al-Attiyah, Batoul Khalifa, Fatima Al-Kubaisi e Abdallah Badahdah. The Impact of Blockade on Families in Qatar. 2a ed. Hamad Bin Khalifa University Press, 2019. http://dx.doi.org/10.5339/difi_9789927141003.
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The study is aimed at assessing the impact of the blockade imposed by the Kingdom of Saudi Arabia, the Kingdom of Bahrain, the United Arab Emirates, and Egypt on June 5th, 2017 on families in Qatar. This study was conducted by corresponding with a group of mixed Qatari families in which one of the spouses is a national of one of the blockading Gulf nations in addition to on a group of families who have relatives living in one of those countries.
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Head, Paul D. The Choral Experience. Editado por Frank Abrahams e Paul D. Head. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780199373369.013.3.
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Much has changed in the choral rehearsal room over the past two generations, particularly in regard to the role the choral conductor assumes—or commands—in the rehearsal process. This chapter discusses the ever-evolving stereotypical roles of the conductor, while examining alternatives to traditional leadership models with particular emphasis on the encouragement of student engagement and peer-based learning. In addition to the facilitation of collaborative learning exercises, the chapter outlines a specific process of written interaction with the choral ensemble. This section is inspired by the renowned “Dear People” letters of Robert Shaw. Finally, in response to the recently revised National Standards for Music Education in the United States, the author discusses possible implementation of the Standards in a performance-based classroom. In the shadow of the relatively recent phenomena of collegiate a cappella groups, these student ensembles have created a new paradigm for peer-led instruction.
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Moseley, Mason W. Narrowing the Focus. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190694005.003.0006.
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This chapter introduces a provincial-level adaptation of my theory of the protest state. In addition to its high levels of protest activity, Argentina is a federal system where incidences of protest participation have occurred at uneven rates, making it an excellent case for exploring variation in rates of contention across provincial contexts. Focusing on the provinces of Buenos Aires, Mendoza, and San Luis—where I draw on dozens of interviews with citizen activists, movement organizers, and politicians conducted in 2013 with support from the National Science Foundation—I utilize the comparative method to examine how distinct institutional characteristics of each province have interacted with citizen engagement to produce different outcomes in terms of protest.
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Goldzweig, Gil, Ilanit Hasson-Ohayon, Gali Elinger, Anat Laronne, Reut Wertheim e Noam Pizem. Adaptation of Meaning-Centered Group Psychotherapy in the Israeli Context. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780199837229.003.0012.
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The implementation and dissemination of psychosocial interventions across different countries is a major challenge to clinicians worldwide. Cultural and societal considerations are required during these adaptations. These considerations include logistic, context-based, and thematic aspects. This chapter describes the process of adapting meaning-centered group psychotherapy (MCGP) to the Israeli context. The chapter discusses the general considerations in intervention adaptation and describes the application of these considerations to the Israeli culture. The description is accompanied by a discussion of the special characteristics of Israeli society that require attention while implementing the MCGP. The chapter also presents preliminary results of two MCGP pilot interventions conducted in Israel. In addition, the chapter presents a clinical example based on excerpts from two MCGP sessions.
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Betz, Matthias, e Volker Wulf. Toward Transferability in Grounded Design. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198733249.003.0016.
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Grounded design is a particular design-research approach applied in case studies. The approach aims to investigate social practices with the purpose of identifying and unveiling problematic aspects of that practice. In research contexts, design case studies are conducted by applying established research methods such as ethnographic field studies, participatory design, and action research. As a research approach, grounded design claims to contribute to scientific knowledge by creating a collection of documented cases that is accessible for a further comprehensive and overarching analysis. This chapter provides an example of such a study through a comparison of two design case studies in the field of civil security research, in the context of firefighting: the Landmarke project and the Koordinator project. In addition, this chapter addresses the transferability of design case studies.
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Trotter, Henry, Catherine Kell, Michelle Willmers, Eve Gray e Thomas K. C. King. Seeking Impact and Visibility: Scholarly Communication in Southern Africa. African Minds, 2014. http://dx.doi.org/10.47622/978-1-920677-51-0.
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African scholarly research is relatively invisible globally because even though research production on the continent is growing in absolute terms, it is falling in comparative terms. In addition, traditional metrics of visibility, such as the Impact Factor, fail to make legible all African scholarly production. Many African universities also do not take a strategic approach to scholarly communication to broaden the reach of their scholars'work. To address this challenge, the Scholarly Communication in Africa Programme (SCAP) was established to help raise the visibility of African scholarship by mapping current research and communication practices in Southern African universities and by recommending and piloting technical and administrative innovations based on open access dissemination principles. To do this, SCAP conducted extensive research in four faculties at the Universities of Botswana, Cape Town, Mauritius and Namibia.
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Benstead, Lindsay J. Survey Research in the Arab World. Editado por Lonna Rae Atkeson e R. Michael Alvarez. Oxford University Press, 2017. http://dx.doi.org/10.1093/oxfordhb/9780190213299.013.14.
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Since the first surveys were conducted there in the late 1980s, survey research has expanded rapidly in the Arab world. Almost every country in the region is now included in the Arab Barometer, Afrobarometer, or World Values Survey. Moreover, the Arab spring marked a watershed, with the inclusion of Tunisia and Libya and addition of many topics, such as voting behavior, that were previously considered too sensitive. As a result, political scientists have dozens of largely untapped data sets to answer theoretical and policy questions. To make progress toward measuring and reducing total survey error, discussion is needed about quality issues, such as high rates of missingness and sampling challenges. Ongoing attention to ethics is also critical. This chapter discusses these developments and frames a substantive and methodological research agenda for improving data quality and survey practice in the Arab world.
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Nauta, Joske, Willem van Mechelen e Evert ALM Verhagen. Epidemiology and prevention of sports injuries. Editado por Neil Armstrong e Willem van Mechelen. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198757672.003.0040.
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Although sports injuries in children are common, prevention of these injuries is paramount. In order to set out effective prevention programmes, epidemiological studies need to be conducted on incidence, severity, and aetiology of sports injuries. Furthermore, the effectiveness of a preventive measure must be assessed, and the eventual implementation of a programme closely evaluated. When conducting epidemiological studies in sports injuries the injury definition used can have a large impact on the outcome, especially as the aetiology of sports injuries is highly multi-causal and recursive. In addition to distinguishing between ‘sports injury’, ‘sports injury incidence’ and ‘sports participation’, the severity of the injury must be defined by taking six indices into consideration: nature of sports injuries, duration and nature of treatment, sports time loss, working/school time loss, permanent damage, and costs of sports injuries.
Capítulos de livros sobre o assunto "Additif conducteur"
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Rizzo, Francesca, e Alessandro Deserti. "Assessing Co-creation in Relation to Context for RRI Operationalisation". In Springer Series in Design and Innovation, 139–68. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-78733-2_14.
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AbstractPilot projects and experimentations, especially when conducted in restricted contexts, require assessment activities in order to determine not only their success or failure, but also to identify potential for replication, best practices and obstacles to be tackled in the future. In addition to this, monitoring and assessment have been a pressing issue both in the landscapes of co-creation and RRI, the two main fields that SISCODE operates within.
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Jarke, Juliane. "Co-creation in Practice I: Co-creating a Digital Neighbourhood Guide (Bremen Osterholz)". In Public Administration and Information Technology, 71–116. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-52873-7_5.
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Abstract This chapter reports on a co-creation project that was conducted in the city district Bremen Osterholz. A core group of 11 older residents co-created a digital district guide over the duration of ten months. In a first step, the group identified an information gap between existing neighbourhood resources to support older residents and older residents’ awareness about them. The solution proposed was to better inform older adults in order to facilitate social participation in their everyday lives (ranging from consulting services to social encounters and outdoor activities). Members of the core group defined the specific information needs (including relevant attributes for each information category) and collected data for all categories. In addition, focus groups with 80 older residents were conducted with the support of local social care service providers. The focus groups were used partly for collecting information about the district, but also for testing the first prototype. The chapter describes co-creation methods such as cultural probes and data tables. It concludes with lessons learned.
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Rauch, Erwin, e Dominik T. Matt. "Status of the Implementation of Industry 4.0 in SMEs and Framework for Smart Manufacturing". In Implementing Industry 4.0 in SMEs, 3–26. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-70516-9_1.
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AbstractIn this chapter, we explore after 10 years of Industry 4.0 the status of the application in manufacturing companies and especially in small- and medium-sized enterprises (SMEs). Based on literature and previously conducted research we present guidelines and a modular framework for implementing smart manufacturing in SMEs. In addition, a stage model is illustrated to support SMEs in breaking down the framework from a design level to an implementation and operational level. Finally, an outlook is given on the future challenges that SMEs will face in the coming years when they want to reach the next level of Industry 4.0 in their own company.
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Beyaert, Simon, e Jean-Pascal Machiels. "Is there a Role for Neoadjuvant Targeted Therapy and Immunotherapy?" In Critical Issues in Head and Neck Oncology, 193–203. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-63234-2_13.
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AbstractNeoadjuvant chemotherapy in head and neck cancer is the subject of much debate. Multiple trials have shown that the concomitant addition of targeted therapies, such as cetuximab to neoadjuvant chemotherapy (docetaxel, cisplatin, 5-fluorouracil), results in increased toxicity. Furthermore, no apparent significant benefit has been demonstrated in small randomized studies. Additional trials are currently being conducted to investigate the role of neoadjuvant immunotherapy, such as anti-PD-(L)1 inhibitors.On the other hand, window of opportunity studies are trials in which patients receive one investigational compound in the period between their cancer diagnosis and the start of standard therapy. The evaluation of new compounds using this approach enables translational research and provides information on molecular and clinical activity as well as predictive biomarkers.
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Erinosho, Mutiu F., Esther T. Akinlabi e Sisa Pityana. "Enhancement of Surface Integrity of Titanium Alloy With Copper by Means of Laser Metal Deposition Process". In Additive Manufacturing, 245–70. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-5225-9624-0.ch010.
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The laser metal deposition process possesses the combination of metallic powder and laser beam respectively. However, these combinations create an adhesive bonding that permanently solidifies the laser-enhanced-deposited powders. Titanium alloys (Ti6Al4V) Grade 5 have been regarded as the most used alloys for the aerospace applications, due to their lightweight properties and marine application due to their excellent corrosion resistance. The improvements in the surface integrity of the alloy have been achieved successively with the addition of Cu through the use of Ytterbium laser system powered at maximum of 2000 Watts. The motivation for this research work can be attributed to the dilapidation of the surface of titanium alloy, when exposed to marine or sea water for a longer period of time. This chapter provides the surface modification of titanium alloy with the addition of percentage range of Cu within its lattices; and the results obtained from the characterizations conducted on the laser deposited Ti6Al4V/Cu alloys have been improved.
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Yayla, Kemal, Basak Ozdemir, Serhat Burmaoglu e Haydar Yalcin. "3D Printing Technology Diffusion". In Additive Manufacturing, 478–502. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-5225-9624-0.ch020.
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3D printing technology has been considered one of the most potentially groundbreaking technologies for the future, as the customer expectations, market requirements, and the competition grows in a global scale. In order to understand the potential effect of 3D printing technology and if it is a disruptive innovation that will change the traditional manufacturing paradigm, it is essential to examine the diffusion of knowledge in this area. In this study, 3D printing technology has been reviewed and patent analysis regarding 3D printing technology has been conducted in order to understand the diffusion of 3D printing technology. The results of the patent analysis indicate that the diffusion of 3D printing technology which is represented by the patents of four key methods not expected to fit with Bass diffusion model. According to the findings, it can be concluded that 3D printing technologies are in a situation where a state of maturity has not been reached, yet the growth still continues.
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Tiwari, Satish Chandra, Maneesha Gupta, Mohammad Ayoub Khan e A. Q. Ansari. "Intellectual Property Rights in Semi-Conductor Industries". In Business Strategies and Approaches for Effective Engineering Management, 97–110. IGI Global, 2013. http://dx.doi.org/10.4018/978-1-4666-3658-3.ch006.
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Fundamentals of intellectual property rights are provided. In addition, the trends of patenting and patented technologies in India in different areas of semi-conductor technologies are analyzed. The authors discuss many aspects of the patents and patentability. They present patent practices in India covering required forms needed to be filled in order to file a patent. Finally, the importance of patenting and its growth is shown with few year wise statistics.
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Tiwari, Satish Chandra, Maneesha Gupta, Mohammad Ayoub Khan e A. Q. Ansari. "Intellectual Property Rights in Semi-Conductor Industries". In Human Rights and Ethics, 214–27. IGI Global, 2015. http://dx.doi.org/10.4018/978-1-4666-6433-3.ch013.
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Fundamentals of intellectual property rights are provided. In addition, the trends of patenting and patented technologies in India in different areas of semi-conductor technologies are analyzed. The authors discuss many aspects of the patents and patentability. They present patent practices in India covering required forms needed to be filled in order to file a patent. Finally, the importance of patenting and its growth is shown with few year wise statistics.
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Chaudhuri, Atanu, e Dennis Massarola. "Economic and Environmental Assessment of Spare Parts Production Using Additive Manufacturing". In Industry 4.0 and Hyper-Customized Smart Manufacturing Supply Chains, 159–81. IGI Global, 2019. http://dx.doi.org/10.4018/978-1-5225-9078-1.ch007.
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This chapter aims to investigate the potential economic and environmental sustainability outcomes of additive manufacturing (AM) for spare parts logistics. System dynamic simulation was conducted to analyze the sustainability of producing a spare part used in a railways subsystem using a particular additive manufacturing (AM) technology (i.e., selective laser sintering [SLS]) compared to producing it using injection molding. The results of the simulation showed that using SLS for the chosen part is superior to the conventional one in terms of total variable costs as well as for carbon footprint. Compared to the conventional supply chain, for the AM supply chain, the costs of the supplier reduces by 46%, that of the railways company reduces by 71%, while the overall supply chain costs reduce by 61.9%. The carbon emissions in the AM supply chain marginally reduces by 2.89% compared to the conventional supply chain.
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Mehdi, Mokhalles Mohammad, e Tridib Ranjan Sarma. "The Labour, Machine, and Material as Sources of Value-Addition for SMEs". In Challenges and Opportunities for SMEs in Industry 4.0, 123–39. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-2577-7.ch008.
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Value addition is a process of changing (converting) input into output with an investment of optimum resources. The present study aims to identify the variables of value addition among MSMEs and its performance in an economy. The study is based on a review of literature from various published sources and analyses to uncover the required variables. Past reviews highlighted that SME performance can be categorized into financial and non-financial characteristics. The previous studies have identified that SME performance depends on the financial factors, marketing factors, production factors, operation activities, and human resources of the enterprises. A survey was conducted among four MSMEs in district industries and commerce centre (DIC), Jorhat (Assam), India using a structured questionnaire constructed from the variables found in past studies. The survey findings highlighted the growth indicators and the challenges that MSMEs faced.
Trabalhos de conferências sobre o assunto "Additif conducteur"
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Khor, Guan Han, Ezuan Hanafi Razali, M. Idham Musa, Saifol Anuar Mat Isa, Wan Helmi Wan Hasan e Daryl Chang. "Challenges and Solutions for Conductor Sharing Technology with Higher Specification Conductor to Meet Target Fatigue Life". In International Petroleum Technology Conference. IPTC, 2021. http://dx.doi.org/10.2523/iptc-21432-ms.
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Abstract Since Conductor Sharing Technology became prominent in the 1990s, the technology has evolved to accommodate the associated well design and construction complexities. In the redevelopment of Brownfield "S", under an alliance between PETRONAS Carigali and other operator, the technology has enabled the number of potential new wells to be increased. However, the technology has been constrained in terms of the available conductor and casing size options. The objective is to advance the current technology to meet the well design and construction requirements. This paper presents the challenges and solutions for conductor sharing technology to accommodate a higher specification conductor (36"×1.5" wall thickness), which is required to meet the fatigue life requirement in Field "S" Phase 3 redevelopment project. Since mid-2018, when PETRONAS took over the operatorship, further conductor analyses have been required. These studies confirmed the requirement for 36" conductor with 1.5" wall thickness, to meet the target fatigue life of 20 years. This paper focuses on a range of key engineering considerations related to well construction including geometrical separation, integration between CWD (casing while drilling) and directional, cementing, and diverter requirement to CWD surface casing. Since there is no existing system that can accommodate this wall thickness and still be able to meet the well construction requirements, a collaboration with the equipment provider has led to the design and manufacture of the world's first splitter wellhead system used for 36" (1.5" WT) × 13-3/8"(2X) × 9-5/8"(2X) × 3-1/2"(4X) with 10,000 psi working pressure rating. The splitter wellhead has allowed two infill wells to be drilled and completed on Platform "A". The system has maximized oil recovery with the additional well. The successful installation and production from this wellhead provide opportunity to reduce construction cost and maximize utilization of existing well slots for future development of brown fields. The improved technology has created more value by allowing surface casing to be installed by CWD in directional sections and the cementing program to be enhanced under diverter system. This solution will be beneficial to similar brown fields which have limited remaining slots and where it is unjustifiable to construct a new platform. In addition, it provides opportunity to lower the wellhead platform cost for green fields by optimizing the number of well slots and platform design.
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Geisen, Ole, Lisa Kersting, Lukas Masseling, Jan Pascal Bogner e Johannes Henrich Schleifenbaum. "Additive Manufacturing of Honeycombs Seal Strips". In ASME Turbo Expo 2018: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/gt2018-77081.
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Laser-Powder Bed Fusion (L-PBF) is an additive manufacturing technique used to melt metal material into solid three-dimensional parts. While offering a high degree of design freedom, L-PBF still has technical restrictions, like the achievable surface roughness, resolution and the need for support structures in overhanging areas. [1] Currently, L-PBF is used mainly to produce small batches of parts and prototypes. [2] In order to fully industrialize the technology, the research campus in Aachen is investigating possible future applications in turbomachinery while developing the corresponding processes with industry partners. Sealing systems, like honeycomb seal strips in gas turbines often require time-consuming joining and assembly operations that can be avoided by building up the structure monolithically using L-PBF. The following process development study proves the feasibility of manufacturing honeycombs with L-PBF using the Nickel-based super-alloy Inconel 718 (IN718) on an EOS M290 machine. Here, we have evaluated the economic aspects of different build orientations of the seal strips. Afterwards, we conducted a systematic parameter study with continuous and pulsed wave laser emission and investigated the resulting wall thicknesses. A reduction in wall thickness of about 30% can be observed when a modulated laser is used.
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Booth, Joran W., Jeffrey Alperovich, Tahira N. Reid e Karthik Ramani. "The Design for Additive Manufacturing Worksheet". In ASME 2016 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/detc2016-60407.
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Additive manufacturing (AM) technologies have become integral to the modern manufacturing process. These roles are filled both in prototyping and production. Many studies have been conducted and lists been written on guidelines for AM. While these lists are useful, virtually none are written in a way that is accessible to novice users of AM, such as Makers. Most guidelines assume the user has extensive prior knowledge of the process, apply to only a few AM technologies, or describe benefits of the technology that novices already know. In this paper, we present a short, visual design-for-additive-manufacturing worksheet for novice and intermittent users. It addresses common mistakes and problems as identified by various expert machinists and additive manufacturing facilities. The worksheet helps designers accurately assess the potential quality of a part that is to be made using an AM process by giving intuitive feedback and indirectly suggest changes to improve a design. The immediate benefit of this worksheet is that it can help to streamline designs and reduce manufacturing errors. We validated it in a high-volume 3D-printing facility (Boilermaker Lab) where users are predominantly novice or intermittent. After the worksheet was implemented in the Boilermaker Lab, both the rate of print failures and reprinted parts fell roughly 40%.
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Han, Yafeng, e Wen F. Lu. "Optimization Design of Nonuniform Cellular Structures for Additive Manufacturing". In ASME 2018 13th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/msec2018-6450.
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Cellular structures are broadly applicable to lightweight design and multifunctional applications. Especially, with unprecedented fabrication freedom provided by additive manufacturing (AM), design and optimization of nonuniform cellular structures have recently attracted great research interests. Topology optimization is one of the most powerful tools to obtain the optimized material distribution, and much research have been conducted to optimize cellular structures with the help of this optimization technique. In general, the optimized cellular structure is generated based on a predefined ground structure, and thickness of each strut is then decided based on the optimization result. However, many existing studies did not consider the constraints of AM processes, such as some generated struts may be too thin to be manufactured. Besides, only load support structure was considered in these studies. Other applications, such as heat dissipation or energy absorption, were rarely researched. In this paper, a novel cellular structure design method, which considered both functionality and manufacturability, is proposed. Different from other methods, wall thickness of the structure was set as a constant. To get the optimized material distribution, variable cell sizes were applied. Because of uniform wall thickness, the smaller the unit cell is, the higher its volume fraction will be. By mapping small unit cells to high density area and large cell to low density area, the final optimized cellular structure can be generated. In addition, because smaller unit cells have higher surface-to-volume ratio, this method can also be applied to solve heat transfer problem. Two examples, minimum compliance design of a cantilever beam and maximum heat dissipation efficiency design of a CPU heat sink, were conducted to validate the proposed method.
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Williams, Dara, e Kevin Purcell. "Optimisation of Conductor System Design to Minimise Wellhead Fatigue Issues". In ASME 2013 32nd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/omae2013-10829.
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Current market trends in the construction of newbuild drilling rigs indicate that the market is driven by demand for ultra-deepwater capacity semi-submersible rigs and drillships. These drilling vessels have capacity to drill in water depths of up to 12,000ft and possibly beyond in the near future. With increase in water depth capacity, more complex and heavier BOP stacks are required. Many modern drilling vessels are now incorporating BOPs with capacities of 20ksi pressure and up to 7 shear/seal rams incorporated. This leads to increased height and weight in the BOP. Whilst newbuild drilling vessels will be required to operate in water depths from 1,500ft to 12,000ft whilst on DP mode, deepwater semi-submersible drilling rigs will also have capability for operation in water depths <1,500ft using conventional mooring. Recent experience with modern deepwater rigs with large BOP stacks in water depth of 1,500ft or less suggests increased risk of fatigue when compared to 3rd generation rigs. If future trends continue with larger BOP stacks being designed then the problem of wellhead fatigue with modern deepwater drilling vessels is likely to become more acute. As noted in previous studies the water depth at drillsite has a major impact on the level of fatigue accumulated in the wellhead system. The main driver for this has been found to be the height and weight of the BOP. With requirements for newbuild drilling rigs for 12,000ft water depth capacity being the industry norm, and with increased requirements for BOP functionality, the gap between wellhead loading from 3rd generation and 6th generation rigs is widening. Given that many 3rd generation rigs will likely be decommissioned in the coming years then the usage of 6th generation rigs for shallow water operations will only become more commonplace due to rig availability. Thus, unless market conditions dictate the construction of smaller and lighter BOP stacks, the design of shallow water wells will be critical to ensure fatigue loading on the wellhead and conductor is kept to a minimum. This paper presents a summary of the results of a series of parameter studies carried out to assess a range of options for optimisation of casing and conductor design for 6th generation rigs in shallow water. Various recommendations are made as part of this study as to the addition of supplemental casing and conductor strings of varying sizes and wall thickness to ensure a robust conductor system design for fatigue performance.
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Oh, Yosep, Sara Behdad e Chi Zhou. "Part Separation Methods for Assembly Based Design in Additive Manufacturing". In ASME 2017 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/detc2017-68002.
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The goal of this study is to develop a heuristic part separation algorithm for assembly-based design in Additive Manufacturing (AM). The objective is to minimize the total processing time including both buildup time and assembly time. In the proposed algorithm, the part separation is recursively conducted until the number of assemblies reaches a threshold value. The proposed method helps designers determine the proper number of assemblies and their buildup orientations. A numerical example is provided to illustrate the application of the algorithm.
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Jing, Liting, e Junfeng Ma. "Additive Manufacturing Adaptiveness Analysis Using Fuzzy Bayesian Network". In ASME 2020 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/detc2020-22535.
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Abstract Additive manufacturing (AM) is a revolutionary manufacturing technology that can produce products in a layer by layer manner. Because of its significant merits in complex geometry and fast fabrication, AM has received worldwide attentions from both industries and academia. Although extensive studies have been conducted on the aspects of process design, prototyping, quality control and reliability, the study of adopting AM in the application is still not fully investigated, which motives this study. In order to close this gap, this study proposes a fuzzy Bayesian Network based approach to discover the applicability of AM. Twelve features of AM applicability obtained from existing literature have been considered in the analysis; fuzzy linguistic description was used to capture the users’ perception; fuzzy Bayesian Network based causation model was developed to study the AM’s adaptiveness. The jet engine blade case study was applied to demonstrate the applicability of the proposed approach. The results showed that fuzzy Bayesian Network based causation approach is able to provide the robust and reliable results of applicability analysis and could also be extended to other risk assessment related design decision making process.
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O’Connor, B. M. "The Influence of Additive Chemistry on Gear Micropitting". In ASME 2003 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/detc2003/ptg-48125.
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Gear micropitting has been a highly visible issue in selected applications in recent years, most notably in large wind turbine transmissions. Various industry groups have addressed the problem from their own area of expertise. This has included evaluation of the gear design characteristics, surface finishing, the use of special coatings, and lubrication. A common approach to improve the lubrication has been first to increase the viscosity and create thicker films, which, in turn, reduce the amount of surface asperity interaction. Another approach from the lubricant side has been to alter the additive chemistry to effect a change in the wear properties of the system. This paper discusses the potential effects observed for different antiwear and EP chemistry on the micropitting of cylindrical gears. Tests were conducted in an FZG test rig which has been used by the industry as a guide to general gear performance. Fluids were examined in a series of experimental designs which served as the iterative process leading toward an optimized additive system. The results show that the EP, or antiscuff agent, was the most effective component at reducing the level of micropitting.
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Lauff, Carlye A., K. Blake Perez, Bradley A. Camburn e Kristin L. Wood. "Design Principle Cards: Toolset to Support Innovations With Additive Manufacturing". In ASME 2019 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/detc2019-97231.
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Abstract Additive manufacturing (AM) continues to play an important role in product development, and many companies are searching for how to best integrate AM into their products, business models, and design processes. Often, AM is integrated into later stages of the design process for products during manufacturing and production. However, there is an opportunity to introduce AM in early-stage design, which could spark new business models and services in addition to re-thinking manufacturing for products. The central research question for this paper is what is an appropriate and useful tool to support innovations with AM early in the design process? Prior work has extracted and validated AM design principles. This paper describes the strategic development of AM Principle Cards from these design principles. The cards are a vehicle for codified AM design principles to be shared and understood in a way that inspires learning, creativity, and AM considerations during the early stages of the design process. They implement a number of best-known practices from an inductive principle-extraction study and literature related to the use of design stimuli, learning theory, design by analogy, and creativity. The AM cards were awarded a Singapore Good Design Award (SG Mark) for 2019. The AM Principle Cards were validated in two studies. In this paper, an ideation study is conducted with 85 designers to elicit feedback about the cards’ effectiveness to explain concepts related to AM and their ability to inspire creativity and new innovations. An additional ideation study was conducted with 61 participants that showed significant improvement in quality and novelty of ideas. The full deck of the final 27 AM Principle Cards is shared for design educators and practitioners to use.
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McNelly, Brendan P., Richard L. Hooks, William R. Setzler e Craig S. Hughes. "Additive Manufacturing of Pressure Vessels (With Plating)". In ASME 2017 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/pvp2017-65888.
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Additive manufacturing (AM) allows for product development with light weight, fewer machining constraints, and reduced costs depending on the application. While AM is an emerging field, there is limited research on the use of AM for pressure vessels or implementation in high stress environments. Depending on the design approach and limitations of traditional material-removal fabrication techniques, AM parts can achieve high strength-to-weight ratios with reduced manufacturing efforts. Coupling AM with alternative metal and composite materials allows for unique designs that have high strength-to-weight ratios for pressure-based applications. The Johns Hopkins University Applied Physics Laboratory (JHU/APL) has conducted research on a number of these composite designs, focusing on the use of carbon fiber or metal plating with the AM materials. Before implementing AM in field tested prototypes, JHU/APL performed strength limitation tests on AM pressure vessels (PVs) in the laboratory to prove their effectiveness. PVs constructed with varying thicknesses and coating techniques were divided into three groups, each with a uniform wall thickness that provided a congruent surface area to withstand higher pressures. These PVs were then paired with one of three coating/plating technologies, forming a trade matrix of varying AM thicknesses and plating techniques. Once fabricated and plated, these test PVs were hydro-statically tested at increasing pressure levels. This pressure testing demonstrates that the use of AM to create PVs, when paired with specific plating techniques, can result in structures with significant strength capabilities at lighter than normal PV weights. Furthermore, JHU/APL has begun to test the AM PVs in a number of research projects. Such testing is desired because these unique parts can be easily manufactured in shapes and volumes that were previously unattainable through common manufacturing techniques. AM parts are now commonly used in air-frames; however, in higher pressure underwater scenarios AM’s capabilities are unproven. JHU/APL has begun to apply this new and emergent field to the effective design of AM PVs, which can play a significant role in the field of underwater vehicles and similar projects.
Relatórios de organizações sobre o assunto "Additif conducteur"
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Simms, Janet, Benjamin Breland e William Doll. Geophysical investigation to assess condition of grouted scour hole : Old River Control Complex—Low Sill Concordia Parish, Louisiana. Engineer Research and Development Center (U.S.), setembro de 2021. http://dx.doi.org/10.21079/11681/41863.
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Geophysical surveys, both land-based and water-borne, were conducted at the Old River Control Complex‒Low Sill, Concordia Parish, LA. The purpose of the surveys was to assess the condition of the grout within the scour region resulting from the 1973 flood event, including identification of potential voids within the grout. Information from the ground studies will also be used for calibration of subsequent marine geophysical data and used in stability analysis studies. The water-borne survey consisted of towed low frequency (16-80 MHz) ground penetrating radar (GPR), whereas the land-based surveys used electrical resistivity and seismic refraction. The GPR survey was conducted in the Old River Channel on the upstream side of the Low Sill structure. The high electrical conductivity of the water (~50 mS/m) precluded penetration of the GPR signal; thus, no useful data were obtained. The land-based surveys were performed on both northeast and southeast sides of the Low Sill structure. Both resistivity and seismic surveys identify a layered subsurface stratigraphy that corresponds, in general, with available borehole data and constructed geologic profiles. In addition, an anomalous area on the southeast side was identified that warrants future investigation and monitoring.
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Bates, C. Richards, Melanie Chocholek, Clive Fox, John Howe e Neil Jones. Scottish Inshore Fisheries Integrated Data System (SIFIDS): Work package (3) final report development of a novel, automated mechanism for the collection of scallop stock data. Editado por Mark James e Hannah Ladd-Jones. Marine Alliance for Science and Technology for Scotland (MASTS), 2019. http://dx.doi.org/10.15664/10023.23449.
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[Extract from Executive Summary] This project, aimed at the development of a novel, automated mechanism for the collection of scallop stock data was a sub-part of the Scottish Inshore Fisheries Integrated Data Systems (SIFIDS) project. The project reviewed the state-of-the-art remote sensing (geophysical and camera-based) technologies available from industry and compared these to inexpensive, off-the -shelf equipment. Sea trials were conducted on scallop dredge sites and also hand-dived scallop sites. Data was analysed manually, and tests conducted with automated processing methods. It was concluded that geophysical acoustic technologies cannot presently detect individual scallop but the remote sensing technologies can be used for broad scale habitat mapping of scallop harvest areas. Further, the techniques allow for monitoring these areas in terms of scallop dredging impact. Camera (video and still) imagery is effective for scallop count and provide data that compares favourably with diver-based ground truth information for recording scallop density. Deployment of cameras is possible through inexpensive drop-down camera frames which it is recommended be deployed on a wide area basis for further trials. In addition, implementation of a ‘citizen science’ approach to wide area recording is suggested to increase the stock assessment across the widest possible variety of seafloor types around Scotland. Armed with such data a full, statistical analysis could be completed and data used with automated processing routines for future long-term monitoring of stock.
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Swinson Evans, Tammeka, Suzanne West, Linda Lux, Michael Halpern e Kathleen Lohr. Cancer Symptoms and Side Effects: A Research Agenda to Advance Cancer Care Options. RTI Press, julho de 2017. http://dx.doi.org/10.3768/rtipress.2017.rb.0016.1707.
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Cancer survivors have unique physical, psychological, social, and spiritual health needs. These can include symptoms and side effects associated with cancer and cancer treatment, such as pain, cognitive dysfunction, insomnia, and elevated anxiety and depression. This research brief summarizes a landscape review done for the Patient Centered Outcomes Research Institute (PCORI) to develop a clear, comprehensive understanding of the state of research as of the mid-2000s. We conducted a targeted search strategy to identify projects funded by federal and commercial sources and the American Cancer Society (ACS) in addition to identifying funding opportunities released by the National Institutes of Health (NIH). We conducted additional review to identify studies focused on symptom and side-effect measures and five priority topic areas (selected by PCORI prior to the review) in the following five databases (from January 2005- through September 2015) with an inclusion criteria in an adapted PICOTS framework (populations, interventions, comparators, outcomes, time frames, and settings). We identified 692 unduplicated studies (1/2005 to 9/2015) and retained 189 studies about cancer symptom and side-effect management. Of these studies, NIH funded 40% and the ACS 33%. Academic institutions, health care systems, other government agencies, and private foundations or industry supported the remainder. We identified critical gaps in the knowledge base pertaining to populations, interventions, comparators (when those are relevant for comparative effectiveness reviews), and outcomes. We also discovered gaps in cross-cutting topics, particularly for patient decision-making studies, patient self-management of cancer symptoms and side effects, and coordinated care.
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Becker, Peter J. Using the Light Weight Deflectometer for Performance-Based Quality Assurance Testing of Cement Modified Subgrades. Purdue University, 2021. http://dx.doi.org/10.5703/1288284317304.
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This report documents the findings from SPR-4230 (Alternative Quality Assurance Methods for Compacted Subgrade). The main objective of SPR-4230 involved establishing performance-related quality assurance (QA) test methods for pavement subgrade construction. Because INDOT generally prefers specifying subgrade treatment type IBC (i.e., 14-in. cement modified subgrade), this study focused on performance-based QA test methods for constructing cement modified subgrade. Moreover, INDOT prefers using light weight deflectometer (LWD) for chemically modified subgrade construction acceptance, so this study aimed to use LWD deflection measurements as performance-related construction acceptance criteria. A laboratory study was performed to relate LWD deflections with resilient modulus that is the key subgrade performance-related parameter in pavement design. In addition, LWD deflections were related with unconfined compressive strength increase that is the key parameter in chemical soil modification mix design. A rigorous field study consisting of LWD testing and falling weight deflectometer (FWD) testing at INDOT new pavement construction sites was conducted to verify the laboratory developed relationship. Recommendations for implementing results of this study into cement modified subgrade construction acceptance is provided, as are recommendations for future research.
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Marinshaw, Richard, Michael Gallaher, Tanzeed Alam e Nadia Rouchdy. Technology Costs as a Barrier to Energy and Water Efficiency in the Commercial Sector of the United Arab Emirates. RTI Press, junho de 2017. http://dx.doi.org/10.3768/rtipress.2017.pb.0013.1706.
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Studies have shown that the United Arab Emirates (UAE) has some of the highest electricity and water consumption rates in the world. To understand the barriers to the adoption of energy and water efficiency, Emirates Wildlife Society in association with the World Wildlife Fund conducted 363 face-to-face interviews with representatives of companies tasked with energy and water management. The purpose was to understand the most important barriers hindering the UAE’s private sector from achieving wide-scale energy and water efficiency and to begin to identify solutions to mitigate these barriers. This paper focuses on technology costs as a barrier to energy and water efficiency in the commercial sector. Preliminary analysis indicates that, for the commercial sector, a contributing factor to the perception that efficient technologies are costly is the lack of accurate information on the full range and life cycle costs and benefits of efficient products. The most immediate solutions would be to address the financing and informational aspects of the technology cost barrier, as well as potentially provide incentives, such as rebates. In addition, attention must be given to barriers underlying many of the technology cost issues, such as subsidized tariffs and relatively few standards that would encourage adoption.
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Berkowitz, Jacob, Nathan Beane, Kevin Philley, Nia Hurst e Jacob Jung. An assessment of long-term, multipurpose ecosystem functions and engineering benefits derived from historical dredged sediment beneficial use projects. Engineer Research and Development Center (U.S.), agosto de 2021. http://dx.doi.org/10.21079/11681/41382.
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The beneficial use of dredged materials improves environmental outcomes while maximizing navigation benefits and minimizing costs, in accordance with the principles of the Engineering With Nature® (EWN) initiative. Yet, few studies document the long-term benefits of innovative dredged material management strategies or conduct comprehensive life-cycle analysis because of a combination of (1) short monitoring time frames and (2) the paucity of constructed projects that have reached ecological maturity. In response, we conducted an ecological functional and engineering benefit assessment of six historic (>40 years old) dredged material–supported habitat improvement projects where initial postconstruction beneficial use monitoring data was available. Conditions at natural reference locations were also documented to facilitate a comparison between natural and engineered landscape features. Results indicate the projects examined provide valuable habitat for a variety of species in addition to yielding a number of engineering (for example, shoreline protection) and other (for example, carbon storage) benefits. Our findings also suggest establishment of ecological success criteria should not overemphasize replicating reference conditions but remain focused on achieving specific ecological functions (that is, habitat and biogeochemical cycling) and engineering benefits (that is, storm surge reduction, navigation channel maintenance) achievable through project design and operational management.
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Kopp, Gregory A., David Sills, Emilio S. Hong e Joanne Kennell. Northern Tornadoes Project. Northern Tornadoes Flyover Project: Summary Technical Report of the Year 1 Pilot Study. Western Libraries, Western University, janeiro de 2018. http://dx.doi.org/10.5206/ntpr181.
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12 January 2018 The objectives of the Year 1 Pilot Study were to (i) develop a methodology for determining tornado occurrence in Northern Ontario, and (ii) obtain research quality data for at least one event. Because of the isolation of many regions, the approach assumed the use of radar data analysis combined with aerial surveys. These objectives were achieved. Aerial surveys were conducted for a total of seven events in Ontario and southern Quebec and 15 confirmed or probable tornadoes identified. Archival geo-tagged imagery was obtained for six of these events. Ten confirmed or probable tornadoes were identified in Ontario, five of which were not in the OSPC database. In addition, 5 tornadoes were confirmed in Quebec. For the 2017 season, the OSPC had a list of 10 verified tornadoes, as of December 21, 2017. The pilot project raises this number to 15. In total, 4 EF2 tornadoes and 1 EF3 tornado were identified via aerial photography. The remainder were EF1 or EF0. UPDATE – 23 April 2018 Based on the analysis of newly available Planet.com high-resolution satellite imagery and related tools, several events were reassessed and a number of additional tornadoes were discovered. Overall, an additional three tornadoes were added to 2017 count. The updated events are listed in a revised 2017 summary table appended at the end of this document.
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Lumpkin, Shamsie, Isaac Parrish, Austin Terrell e Dwayne Accardo. Pain Control: Opioid vs. Nonopioid Analgesia During the Immediate Postoperative Period. University of Tennessee Health Science Center, julho de 2021. http://dx.doi.org/10.21007/con.dnp.2021.0008.
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Background Opioid analgesia has become the mainstay for acute pain management in the postoperative setting. However, the use of opioid medications comes with significant risks and side effects. Due to increasing numbers of prescriptions to those with chronic pain, opioid medications have become more expensive while becoming less effective due to the buildup of patient tolerance. The idea of opioid-free analgesic techniques has rarely been breached in many hospitals. Emerging research has shown that opioid-sparing approaches have resulted in lower reported pain scores across the board, as well as significant cost reductions to hospitals and insurance agencies. In addition to providing adequate pain relief, the predicted cost burden of an opioid-free or opioid-sparing approach is significantly less than traditional methods. Methods The following groups were considered in our inclusion criteria: those who speak the English language, all races and ethnicities, male or female, home medications, those who are at least 18 years of age and able to provide written informed consent, those undergoing inpatient or same-day surgical procedures. In addition, our scoping review includes the following exclusion criteria: those who are non-English speaking, those who are less than 18 years of age, those who are not undergoing surgical procedures while admitted, those who are unable to provide numeric pain score due to clinical status, those who are unable to provide written informed consent, and those who decline participation in the study. Data was extracted by one reviewer and verified by the remaining two group members. Extraction was divided as equally as possible among the 11 listed references. Discrepancies in data extraction were discussed between the article reviewer, project editor, and group leader. Results We identified nine primary sources addressing the use of ketamine as an alternative to opioid analgesia and post-operative pain control. Our findings indicate a positive correlation between perioperative ketamine administration and postoperative pain control. While this information provides insight on opioid-free analgesia, it also revealed the limited amount of research conducted in this area of practice. The strategies for several of the clinical trials limited ketamine administration to a small niche of patients. The included studies provided evidence for lower pain scores, reductions in opioid consumption, and better patient outcomes. Implications for Nursing Practice Based on the results of the studies’ randomized controlled trials and meta-analyses, the effects of ketamine are shown as an adequate analgesic alternative to opioids postoperatively. The cited resources showed that ketamine can be used as a sole agent, or combined effectively with reduced doses of opioids for multimodal therapy. There were noted limitations in some of the research articles. Not all of the cited studies were able to include definitive evidence of proper blinding techniques or randomization methods. Small sample sizes and the inclusion of specific patient populations identified within several of the studies can skew data in one direction or another; therefore, significant clinical results cannot be generalized to patient populations across the board.
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Kyllönen, Katriina, Karri Saarnio, Ulla Makkonen e Heidi Hellén. Verification of the validity of air quality measurements related to the Directive 2004/107/EC in 2019-2020 (DIRME2019). Finnish Meteorological Institute, 2020. http://dx.doi.org/10.35614/isbn.9789523361256.
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This project summarizes the results from 2000–2020and evaluates the trueness andthequality control (QC) procedures of the ongoing polycyclic aromatic hydrocarbon (PAH)and trace element measurements in Finlandrelating to Air Quality (AQ) Directive 2004/107/EC. The evaluation was focused on benzo(a)pyrene and other PAH compounds as well as arsenic, cadmium and nickel in PM10and deposition. Additionally, it included lead and other metals in PM10and deposition, gaseous mercury and mercury deposition, andbriefly other specificAQ measurements such as volatile organic compounds (VOC)and PM2.5chemical composition. This project was conducted by the National Reference Laboratory on air quality and thiswas the first time these measurements were assessed. A major part of the project was field and laboratory audits of the ongoing PAH and metal measurements. Other measurements were briefly evaluated through interviews and available literature. In addition, the national AQ database, the expertise of local measurement networks and related publications were utilised. In total, all theseven measurement networks performing PAH and metal measurements in 2019–2020took part in the audits. Eleven stations were audited while these measurements are performed at 22 AQ stations in Finland. For the large networks, one station was chosen to represent the performance of the network. The audits included also six laboratories performing the analysis of the collected samples. The audits revealed the compliance of the measurements with the AQ Decree 113/2017, Directive 2004/107/EC and Standards of the European Committee for Standardization(CEN). In addition, general information of the measurements, instruments and quality control procedures were gained. The results of the laboratory audits were confidential,but this report includes general findings, and the measurement networks were informed on the audit results with the permission of the participating laboratories. As a conclusion, the measurementmethodsusedwere mainly reference methods. Currently, all sampling methods were reference methods; however, before 2018 three networks used other methods that may have underestimated concentrations. Regarding these measurements, it should be noted the results are notcomparable with the reference method. Laboratory methods were reference methods excluding two cases, where the first was considered an acceptable equivalent method. For the other, a change to a reference method was strongly recommended and this realized in 2020. For some new measurements, the ongoing QC procedures were not yet fully established, and advice were given. Some networks used consultant for calibration and maintenance, and thus theywere not fully aware of the QC procedures. EN Standards were mostly followed. Main concerns were related to the checks of flow and calculation of measurement uncertainty, and suggestions for improvement were given. When the measurement networks implement the recommendations given inthe audits, it can be concluded that the EN Standards are adequately followed in the networks. In the ongoing sampling, clear factors risking the trueness of the result were not found. This applies also for the laboratory analyses in 2020. One network had concentrations above the target value, and theindicative measurementsshould be updated to fixed measurements.
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Ama Pokuaa, Fenny, Aba Obrumah Crentsil, Christian Kwaku Osei e Felix Ankomah Asante. Fiscal and Public Health Impact of a Change in Tobacco Excise Taxes in Ghana. Institute of Development Studies (IDS), novembro de 2020. http://dx.doi.org/10.19088/ictd.2020.003.
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This working paper predicts the fiscal and public health outcomes from a change in the excise tax structure for cigarettes in Ghana. More than 5,000 people are killed by diseases caused by tobacco every year in Ghana (Tobacco Atlas 2018). Currently the country has a unitary tax administration approach, with a uniform ad valorem tax structure on all excisable products, including tobacco. However, the ECOWAS directive on tobacco control, in line with the WHO Framework Convention on Tobacco Control (WHO 2003), recommends a simple tax structure – using a mixed excise system with a minimum specific tax floor to overcome the limitations of an ad valorem system on tobacco products, especially cigarettes. The study therefore simulates mixed tax policy interventions, and assesses their effect on government revenue and public health relative to the current ad valorem tax system. Primary data collection of tobacco prices in three geographical zones of the country was conducted in February 2020, across both rural and urban localities. This was supported with secondary data from national and international databases. Based on the assumption that Ghana adopts a mixed tax structure, the simulation shows that, if the government imposes a specific excise tax of GH₵4.00 (US$0.80) per pack in addition to the current ad valorem rate of 175 per cent of the CIF value, the average retail price of a cigarette pack would increase by 128 per cent, cigarette consumption decrease by 27 per cent, tobacco excise tax revenue increase by 627 per cent, and overall tobacco-related government tax revenue increase by 201 per cent.1 Additionally, there would be significant declines in smoking prevalence (3.3%), smoking intensity (1,448 cigarettes per year), and 3,526 premature smoking-related deaths would be avoided. The paper advocates for a strong tax administration and technical capacity, with continuous commitment by the government to adjust the tax rate in line with the rate of inflation and per capita income growth.