Thèses sur le sujet « Seals (Cylinders) »

Hydraulic cylinder seal performance is studied experimentally and theoretically. The seal performance is discussed in terms of friction force and oil leakage, which are due to the oil film build-up in the seal contact. The theoretical analysis is based both on calculated and measured contact pressure distributions. The compressibility of seal materials is determined experimentally, and it is shown that the compressibility is a pressure dependent material property. A method for calculation of the contact pressure distribution for a seal with an arbitrary cross-section is proposed, based on geometrical considerations and the experimentally determined compressibility. The pressure calculations are verified experimentally. Theoretically calculated oil film thicknesses in a seal contact are compared with measured film thicknesses. The increase of film thickness with increasing sliding velocity shows a good agreement between theory and experiment. The oil film is thicker in the experiments due to the surface roughness of the seal. A complete theoretical analysis of the seal performance is developed to be used as a design tool.
Godkänd; 1987; 20070424 (ysko)

The ancient region of Elam (southwestern Iran) has produced a significant assemblage of cylinder seals across a considerable chronological span. Unlike the glyptic material from the related and neighbouring region Mesopotamia, the Elamite cylinder seals have not previously been studied in detailed reference to one another, nor has there been an established paradigm of stylistic development articulated. This study addresses this lacuna by compiling all the published cylinder seals from Elam (as defined here, thus incorporating the historical provinces of Khuzistan, Luristan and Fars), from their earliest appearance (c.3500 BC), throughout the era of their typological dominance (over stamp seals, thus this study departs c.1000 BC). This compilation is presented in the Elamite Cylinder Seal Catalogue (Volume II), and is annotated and described through the annunciation of eighteen chronologically defined developmental styles (with another two non-chronological type classifications and four miscellaneous groups). Through the further analysis of this data, including the newly formulated and articulated styles, several facets and problems of Elamite glyptic material have been addressed (and thus the reliance upon assumed similarity in type and function with the Mesopotamian glyptic material is abandoned). These problems particularly pertain to the function of cylinder seals in Elam and the type and form of the Elamite-Mesopotamian glyptic interaction. In regards to function, a standard administrative function can be discerned, though of varying types and forms across the region and the period of study. Other, non-standard, symbolic glyptic functions can also be demonstrated in the Corpus, including the apparent proliferation of a form known as the ‘votive’ seal, perhaps a specifically Elamite form. The analysis of the style type (whether ‘Elamite’, ‘Mesopotamian Related’ or ‘Shared Elamite-Mesopotamian’), in association with their relative geographical and chronological distribution, has also enabled the discussion of the nature of Elamite-Mesopotamian glyptic interaction, and thereby the constitution of Elamite civilisation (especially in regards to Mesopotamian cultural impact and influence, and thus the testing of several previously presented paradigms [Amiet 1979a; 1979b; Miroschedji 2003]).

Doctor of Philosophy
The ancient region of Elam (southwestern Iran) has produced a significant assemblage of cylinder seals across a considerable chronological span. Unlike the glyptic material from the related and neighbouring region Mesopotamia, the Elamite cylinder seals have not previously been studied in detailed reference to one another, nor has there been an established paradigm of stylistic development articulated. This study addresses this lacuna by compiling all the published cylinder seals from Elam (as defined here, thus incorporating the historical provinces of Khuzistan, Luristan and Fars), from their earliest appearance (c.3500 BC), throughout the era of their typological dominance (over stamp seals, thus this study departs c.1000 BC). This compilation is presented in the Elamite Cylinder Seal Catalogue (Volume II), and is annotated and described through the annunciation of eighteen chronologically defined developmental styles (with another two non-chronological type classifications and four miscellaneous groups). Through the further analysis of this data, including the newly formulated and articulated styles, several facets and problems of Elamite glyptic material have been addressed (and thus the reliance upon assumed similarity in type and function with the Mesopotamian glyptic material is abandoned). These problems particularly pertain to the function of cylinder seals in Elam and the type and form of the Elamite-Mesopotamian glyptic interaction. In regards to function, a standard administrative function can be discerned, though of varying types and forms across the region and the period of study. Other, non-standard, symbolic glyptic functions can also be demonstrated in the Corpus, including the apparent proliferation of a form known as the ‘votive’ seal, perhaps a specifically Elamite form. The analysis of the style type (whether ‘Elamite’, ‘Mesopotamian Related’ or ‘Shared Elamite-Mesopotamian’), in association with their relative geographical and chronological distribution, has also enabled the discussion of the nature of Elamite-Mesopotamian glyptic interaction, and thereby the constitution of Elamite civilisation (especially in regards to Mesopotamian cultural impact and influence, and thus the testing of several previously presented paradigms [Amiet 1979a; 1979b; Miroschedji 2003]).

Cylinder seal impressions occur in many contexts in the ancient Near East. This disssertation focuses specifically on the function of sealing in the manipulation of state resources (land, labor, and goods) in second millennium B.C. Syria. The sources of information utilized in this study include textual references to sealing practices, sealed documents, bullae, and the seals themselves. The archives of Mari, Alalah, and Ugarit are particularly important as they provide textual and archaeological information on seals and sealing within the physical and institutional context of the palace, the center of state administration. Chapter 1 surveys the previous research on seals and sealing and briefly outlines Syrian geography and political history in the second millennium B.C. Chapter 2 examines the physical qualities of the seals--materials, methods of production, distribution and style. Chapter 3 addresses the problem of the physical and institutional context of seal use. A functional division between legal and administrative texts is reflected in the use of seals on them. On both types of documents, however, the use of a seal acknowledges the obligation of the sealer. The nature of that obligation varies with the contents of the text itself. Chapter 4 evaluates the use of seals on legal texts in palace archives. Most of these sealed documents record land grants. The historical trend in second millennium Syria is to an increasing involvement of heads-of-state in granting state land. Other sealed legal documents were kept in palace archives because the participants were in some way associated with the palace. Chapter 5 details the administrative use of seals at Mari. Receipts and expenditures are the most common sealed documents. The use of seals on these texts signals the acceptance by the sealer of responsibility for the goods or actions described therein. The conclusions (Chapter 6) summarize the differences in sealing practices in Mari, Alalah and Ugarit in light of the different historical circumstances and political needs of each state.

For the transport of their spacecraft from the vehicle assembly building to the launch pads at Kennedy Space Centre, Florida, the National Aeronautics and Space Administration (NASA) is using two special crawler transporters since 1965. First developed for the Saturn V rocket the crawler transporters have been sufficient for all following generations of space ships so far. But for the new generation of Orionspacecraft which is under development now, a load capacity increase for the crawler transporter of plus 50% was necessary. For this task Hunger Hydraulik did develop new jacking, equalizing and levelling (JEL) cylinders with sufficient load capacity but also with some new features to improve the availability, reliability and safety of this system. After design approval and manufacture of the cylinders they have been tested in a special developed one-to-one scale dynamic test rig and after passing this the cylinders had to prove their performance in the crawler transporter itself. This article describes the general application and introduces the technical requirements of this project as well as the realized solution.

L’étude entreprise visait à examiner l'apport que l'iconographie peut fournir à l’étude de la grande faune mammalienne et à l'évaluation de sa distribution historique au Proche-Orient, en prenant le 4ème et le 3ème millénaire en Syrie du nord comme époque et région cible. Trois objectifs précis étaient posés dans ce cadre (1) Proposer à travers des sources glyptiques contemporaines une vue de la faune des 4ème et 3ème millénaires en Mésopotamie du Nord ;(2) Evaluer la cohérence de cette image par rapport aux données archéozoologiques et par rapport à un modèle géochronologique plus large de l’évolution de la faune régionale ;(3) Evaluer la pertinence de la glyptique comme marqueur pour l’étude de la paléofaune. The object of this study was to examine the contribution that iconography can make to the study of large mammal faunas, focussing on the 4th and 3rd millennia in Upper Mesopotamia (Syria). Three goals were set in this framework (1) To propose a view of 4th and 3rd millennia fauna in Upper Mesopotamia as seen through glyptic sources; (2) To evaluate the coherence of this view in relation to contemporary archaeozoological data and in relation to a wider geochronological model of the regional fauna; (3) To assess the relevance of glyptic as a marker in the study of ancient faunas.
Doctorat en Histoire, histoire de l'art et archéologie
info:eu-repo/semantics/nonPublished

This work deals with the determination of the heat transfer coefficient in small channels with a rotating wall. The research part of the thesis is focused on specific geometry, namely labyrinth seals used in rotary machines. Existing criteria equations determining heat transfer coefficients and other parameters in these specific geometries are described. The central part describes the built experimental device for the determination of values of heat flows and heat transfer coefficients on both stator and rotor for given airflow and rotor speed. The following section is devoted to presenting the results of the performed experiments with the corresponding criteria equations. The next part describes the basic mathematical models of inverse heat conduction problems. Calculations of heat flux using these inverse methods are performed and compared with reference heat flux sensors.

У роботі розроблено компресорну установку без змащування циліндрів і сальників.
В работе разработаны компрессорную установку без смазки цилиндров и сальников.
A compressor unit without lubrication of cylinders and glands is developed in the work.

Cette thèse s'intéresse à la coordination des sous-systèmes d'un nouveau genre de centrale de production d'énergie : un cycle combiné hybride (HCC - Hybrid Combined Cycle). Cette centrale HCC n'existe pas encore mais combine un cycle combiné gaz (CCG), un moyen de production solaire thermodynamique (miroirs cylindro-paraboliques) et un moyen de stockage thermique (stockage indirect de chaleur sensible utilisant deux réservoirs de sels fondus). Comment coordonner ces trois sous-systèmes de manière optimale lors des variations de demande de puissance ou des prix du gaz ?Dans un premier temps, chacun des trois sous-systèmes est étudié de manière indépendante afin d'obtenir, d'une part, un modèle physique permettant de caractériser le comportement dynamique du sous-système considéré et, d'autre part, un contrôle local qui agit en fonction des objectifs de fonctionnement prédéfinis. Un modèle du système complet interconnecté de l'HCC est ensuite obtenu en couplant les modèles des trois sous-systèmes. Enfin, une coordination des différents sous-systèmes est mise en place pour adapter le fonctionnement de chacun, en fonction des objectifs globaux de la centrale HCC complète, en optimisant les consignes de chaque sous-système. Dans ce travail, une coordination de type linéaire quadratique et une coordination de type optimale prédictive sont étudiées. Les résultats obtenus sont bien prometteurs : ils montrent, tout d'abord, que lors d'un appel de puissance, la commande coordonnée permet au système HCC de répondre plus rapidement, en utilisant plus efficacement la partie solaire. De plus, lorsque la demande subit beaucoup de variations, la partie solaire et la partie stockage absorbent toutes ces variations et la Turbine à Combustion (TAC) du CCG est beaucoup moins sollicitée. Lorsqu'il n'y a plus d'irradiation solaire, la partie stockage prend la relève pour continuer à produire de la vapeur solaire, jusqu'à ce que les stocks se vident. Finalement, le stockage permet d'ajuster la production de la TAC en fonction des prix du gaz
This work concerns the subsystems coordination of a new type of power plant: a Hybrid Combined Cycle (HCC). This HCC plant is not yet build but consists of a Combined Cycle Power Plant (CCPP), a concentrated solar plant (parabolic trough) and a thermal storage system (a molten-salts two-tank indirect sensible thermal storage). How to coordinate these three subsystems optimally during variations in power demand or in gas price?First, each subsystem is studied independently in order to get on one hand a physical model that reproduces the dynamical behavior of the considered subsystem, and on the other hand, a local control that achieves an operation according to pre-specified objectives. Then, a model of the HCC system is obtained by coupling the models of the three defined subsystems.Eventually, a coordination of the subsystems is set up in order to adapt the behavior of each subsystem according to the global objectives for the full HCC system, by optimizing subsystem setpoints. In this study, a linear quadratic coordination and a model predictive coordination are designed. The obtained results are promising: they first show that during a power demand, the coordination allows the global system to quickly respond, using extensively the solar production. Besides, when the power demand undergoes many fluctuations, the solar and storage parts absorb these variations and the gas turbine of the CCPP is much less stressed. In addition, when there is no more solar radiation, the storage part continues producing solar steam, until storage tanks are empty. At last, the storage part allows to adjust the gas turbine production according to the gas prices

Dès les premières dynasties, le pictogramme fut dans l’écriture le prolongement des représentations figuratives naturalistes, logogrammes dans les palettes funéraires décorées protodynastiques. Ce constat nous porte à les mettre en correspondance avec l’art pariétal du néolithique nubien, le prédynastique égyptien, et celui des aires culturelles périphériques. La reconsidération des pétroglyphes en tant que symboles et idéogrammes, c’est-à-dire des mythogrammes autant que des logogrammes-phonogrammes polysémiques permet de dégager un système structurel de représentations symboliques universel dans la vallée du Nil. Essentiellement funéraire, il est organisé autour d’une nouvelle lecture en relation aux mythes fondateurs de l’Œil d’Horus/solaire, s’exprime dans des rites primitifs de revivification, de renaissance, néolithiques et prédynastiques, explicités ensuite durant les premières dynasties sur des tablettes, des sceaux-cylindres votifs, et l’onction du mort avec les sept huiles canoniques et, enfin, dans les Textes des Pyramides. Contrairement à l’idée commune d’opposition des notions de Nature-Culture, il est question de les conjuguer, de réconcilier la dualité non binaire et de voir, par exemple, les fonctions héliotrope et/ou héliophore des animaux du bestiaire soudanien, avec Sokar le faucon funéraire, les garants bienveillants des métamorphoses et de renaissance du soleil/des défunts, par ailleurs, félidés, canidés, antilopes…, investis du numineux des divinités tutélaires. À la lueur d’une nouvelle lecture du mythe “osirien” primitif de métamorphose, nous reconsidérons les conceptions sur le sacrifice animal sur des bases d’anthropologie religieuse. Loin d’une maîtrise et soumission de la nature, et d’un diffusionnisme, l’interculturalité de la pensée mythique archaïque première dans la vallée nubiano-égyptienne et des régions périphériques multiethniques implique, vis-à-vis du monde naturel et des forces spirituelles numineuses, la transculturalité des conceptions solaires et le partage pluriculturel, transhistorique des croyances résurrectionnelles polycycliques. Ainsi, les pétroglyphes d’animaux, les scènes de chasse animale, les représentations de barques, de sandales, etc., sont de nature funéraire votive, apotropaïque
Since the beginning of the first dynasties, the pictogram in writing was the extension of naturalistic figurative representations, logograms in the decorated funerary protodynastic palettes. This statement carry us to link them with the parietal art of Neolithic Nubia, the egyptian Predynastic, and peripheral cultural areas. We have reconsidered the petroglyphs as polysemic symbols and ideograms, i.e. mythograms as well polysemic logograms-phonograms, allowing us to draw up a structural system of symbolic representations, universal in the Nile valley. Basically funerary, the system is organised around a new reading in connection with the founding of the ‘Eye of Horus’/solar myths, and express itself in primitive Neolithic and Predynastic rites of revivification, rebirth, more explicit afterwards during the first dynasties on labels, votive cylinder-seals, and anointing the deads with the seven holy canonical oils, finally in the Pyramid Texts. Contrary to the common idea which opposite the Nature-Culture notions, there is some question to combine them, to reconcile the non-binary duality and to see, for example, the heliotrope functions and/or heliophore animals of the sub-Saharan bestiary, with Sokar the funerary hawk, the benevolent guarantors for the rebirth and metamorphosis of the sun/deads; otherwise felids, canids, antelopes…, invested by the numinous of the protecting divinities. In consequence of a new reading of the primitive ‘osirian’ myth of metamorphosis, we have reconsidered the conceptions about animal sacrifice on the basis of religious anthropology. Far from bringing under control and submission of nature, and diffusionnism, the intercultural (cross-cultural) of the first archaic mythic thought in the multi-ethnic nubian-egyptian valley and associated neighbouring areas involves, towards the natural world and the numinous spiritual strengths, the cross-cultural of solar conceptions and multicultural, trans-historic sharing of the polycyclic resurrectional believes. Thus, the animal petroglyphs, cynegetic scenes, boats and sandals representations, etc., are of funerary votive, apotropaic nature

碩士
逢甲大學
機械工程學所
90
Leakage plays an important role on the performance evaluation of hydraulic components. Leakage flow will induce adverse influence on many practical industrial applications. Therefore, most of the hydraulic components install some kind of sealing device to avoid or to reduce the leakage. This research is to investigate the leakage flow of labyrinth seals on a high speed hydraulic cylinder by using numerical analysis method. The parameters investigated in this study are linear velocity, groove type, groove number, groove depth, groove width, groove distance, clearance, and Reynolds number. In accordance with practical industrial problem, the rectangular type and triangular type grooves are both considered. It is shown that groove width is about 20~30 times of clearance, groove depth is about 3~5 times of clearance, and groove distance is greater than 50 times of clearance; the groove depth to width ratio is about 0.15~0.25 and the groove distance to width ratio is greater than 2.5 have better effect on preventing leakage. The results of this research will supply valuable design reference data for the hydraulic component designer and manufacturer.

博士
國立臺北科技大學
機電科技研究所
96
In this study, the friction force of polytetrafluroethylene (PTFE) seal for vehicle brake tandem master cylinder is evaluated through experimental tests, using the proposed testing system. The friction force of seal between exterior aluminum wall and interior piston is typically a combination of several friction regions and the contact friction can be divided into solid friction, boundary lubrication and hydrodynamic lubrication. The static friction force and stick-slip effect is considered as a crucial step to form vibration and predict the life time of the V-shaped seal. The behavior of an elastomeric seal for vehicle Tandem master cylinder is measured and analyzed in velocity by using three types of nanoparticles brake fluids made by our laboratory. Working conditions are simulated for different piston rod velocity and cylinder supply pressure. The results show that nanoaluminum oxide brakefluid with its ball shape can highly reduce friction force to avoid seal excessive wear and reduce slick slip in brake applications. The solid friction force can be reduced by the assistance of the rollingof nanoparticles. Besides, the generalized Sommerfield number in lubrication theory, S0, is increased by the nanoparticles added and increased viscosity. The solid friction is lower due to nanoparticles rolling during the movement start. The nanoparticles provide function of rolling, mend surface and increasing viscous in order to being good lubricants. Accordingly, the friction force is about 3% lower than that without adding nanoparticles in brake system. The frequency and the magnitude of stick-slip are lower than that without adding nanoparticles in brake system. The outstanding physical properties in the operation of vehicle brake master cylinder will lead to reduce the seal excessive wear and reduce stick slip in brake applications.

A glíptica mesopotâmica, enquanto objeto de estudo arqueológico, assume-se como marcadamente polivalente, pois através dela é possível estudar dinâmicas de várias ordens, dado o seu uso transversal ao longo dos mais de três mil anos de história desta civilização. De facto, a par do espólio cerâmico, os selos cilíndricos são, sem dúvida, os artefactos que registam uma maior representatividade nas escavações levadas a cabo no território do atual Iraque e da atual Síria. A região do Diyala, zona centro-sul da Mesopotâmia, intervencionada pelo Instituto Oriental de Chicago, na década de 1930, revelou um enorme potencial arqueológico no que diz respeito a estes objectos, que se traduziu em quatro principais arqueossítios: Tell Asmar, Khafajah, Ishchali e Tell Agrab. A partir do espólio glíptico ali identificado, tornou-se possível revisitar o passado, numa cronologia alargada, que alberga um espetro temporal desde os finais do IV milénio a.C. até aos inícios do II milénio a.C. Tendo como ponto de partida a amostragem do Diyala, procurámos redescobrir o divino feminino mesopotâmico numa ótica de análise interdisciplinar. A glíptica do Diyala traduz uma construção contínua dos arquétipos do divino feminino na Mesopotâmia, ao mesmo tempo que apresenta um pensamento religioso moldado quer por uma lógica oficial, quer pela piedade popular, atestando a confluência entre ambas. As deusas que surgem representadas nas cenas iconográficas aparecem de múltiplas formas, antropomórfica e simbólica, afirmando-se como agentes de poder efetivo a todos os níveis. A polivalência dos espaços onde os selos cilíndricos com representações do divino feminino foram exumados (em estruturas palacianas, em espaços cúlticos e em habitações domésticas) espelham o caráter polivalente conferido a este género na Mesopotâmia.
Mesopotamian glyptic, as an object of archaeological study, presents multiple perspectives that allow to analyse different dynamics, given the transversal use of the cylinder seal during the three thousand years of this civilization’s history. In fact, along with ceramic materials, cylinder seals are, undoubtedly, the artifacts that register a larger representation in the archaeological excavations that have taken place in the modern territories of Iraq and Syria. The Diyala Region, in the south/central area of Mesopotamia, excavated by the Oriental Institute of Chicago in the 1930s, revealed a tremendous archaeological potential regarding these objects, which translated itself in four main sites: Tell Asmar, Khafajah, Ishchali, and Tell Agrab. From the glyptic material identified in these sites, we were able to revisit the past, in a vast chronology, between the end of the 4th millennium and the beginning of the 2nd millennium BCE. With the Diyala’s glyptic material as a starting point, we sought to rediscover the Mesopotamian divine feminine through an interdisciplinary perspective. The Diyala glyptic expresses a continuous construction of the Mesopotamian divine feminine archetypes, and, at the same time, displays a religious thought shaped by the official logic and by popular piety, confirming the confluences between them. The goddesses represented in the cylinder seals appear in multiple forms, anthropomorphic and symbolic, affirming themselves as agents of effective power at all levels. The different spatial contexts where the cylinder seals with representations of the Mesopotamian divine feminine were exhumed (in palatial structures, in cultic spaces, and in domestic houses) reflect the polyvalent character bestowed to the feminine in Mesopotamia.