Les industries lithiques de l’Holocène moyen, entre 8.000 et 4.000 BP dans le centre et le nord-est du Brésil ont souvent été décrites non pas en fonction des caractères présents mais de ceux absents : absence de lesma (pièce façonnée unifacialement), absence de céramique. Les traits techniques spécifiques à la période sont difficiles à cerner à cause de la diversité des artefacts. Décrites comme peu élaborées ou simples, ces industries interrogent pourtant par leurs caractères extrêmement différents de ceux de la période antérieure. Des hypothèses liées à des facteurs externes ont été évoquées pour expliquer de tels changements dans la culture matérielle : changement climatique avec une forte modification de l’environnement, remplacement de la population par une nouvelle vague de peuplement. Toutefois, il est difficile d’évaluer les modalités de cette rupture tant les analyses sur des assemblages de la période sont peu nombreux. Nous proposons dans ce travail de caractériser les systèmes techniques de l’Holocène moyen et par ce biais aborder le phénomène de rupture technique avec le technocomplexe Itaparica. Deux assemblages lithiques de l’Holocène moyen ont été étudiés selon une approche techno-fonctionnelle : la Toca Nova do Inharé dans la Serra da Capivara (Piauí) et le site Cajueiro (BA-RC-19) au nord-est du plateau central (Bahia).Les résultats obtenus mettent en évidence l’existence de caractères partagés et de variabilités importantes. L’organisation des différentes parties fonctionnelles des outils, structurée par la présence récurrente de pans abrupts, constitue un caractère commun fort. Les supports d’outils sont en revanche très variables selon les sites, expliquant cette impression d’absence d’outils clairement définis déjà soulignée.La confrontation de nos résultats aux données disponibles dans la littérature nous a permis d’affirmer ces caractères comme une spécificité des industries de l’Holocène moyen et de confirmer également l’existence d’une rupture technique importante avec le technocomplexe Itaparica. / During middle Holocene, between 8000 and 4000 BP, central and northern Brazil lithic industries were often described in terms of lacks more than tangible characteristics: lacks of “lesma” (unifacial shaping tool), lacks of ceramics. Specific technical features linked to that period are not easy to pinpoint because of a high level of artifacts diversity. Described as somewhat elaborate or simple, the specific nature of these industries highlights differences between this period and the previous one. To explain such a change in material culture, external factor hypothesis were proposed: huge environment modification due to climate change, new population that replaces another one. However, it is uneasy to evaluate break modalities regarding few studies on these period assemblages.Our work proposes to characterize the technical systems for the middle Holocene, and, by this way, to broach the technical break phenomenon using Itaparica techno-complex. Two middle Holocene lithic assemblages were study in a techno-functional way: la Toca Nova do Inharé, in Serra da Capivara (Piauí) and the Cajueiro site (BA-RC-19) northeastern of the central plateau (Bahia). Results reveal shared characteristics and significant variability. Organization of different functional parts of tools outlined around recurrent presence of abrupt sides, form a strong shared feature. Tool blanks have, however, high degree of variability according to different sites, explaining the lack of strictly defined tools. Our results compared to available literature data allow us to confirm that these features are specific to these middle Holocene industries and also to bear out the existence of a significant technical break with the Itaparica techno-complex.

Le modèle « Out of Africa » est profondément ancré dans les réflexions portant sur les peuplements paléolithiques. Pour le Pléistocène inférieur et moyen ancien, plusieurs vagues de dispersion des premiers hominidés à partir de l’Afrique de l’Est sont avancées, en particulier vers le Proche-Orient sur la base de trois sites majeurs : Dmanisi, ‘Ubeidiya et Gesher Benot Ya‘aqov. Cette théorie véhicule également l’idée d’imports répétés de techniques nouvelles, notamment le façonnage bifacial.Cependant, une déconstruction des mécanismes inhérents à ce modèle permet d’identifier des obstacles conceptuels et méthodologiques issus du « paradigme de la flèche », simplifiant et réduisant la complexité des phénomènes techniques et culturels.Afin de réintégrer à la question l’espace et le temps, dont l’absence au sein d’« Out of Africa » est rédhibitoire, nous utilisons une vision évolutive des techniques basée sur des réflexions de philosophie, d’ergonomie et de géographie. Cette vision, reprise par des paléolithiciens depuis une quinzaine d’années, a conduit à concevoir une méthodologie techno-fonctionnelle centrée sur les notions d’outil, de geste et de fonctionnement.Une étude approfondie utilisant cette approche a été menée sur quatre assemblages est-africains et proche-orientaux, complétée par des observations portant sur trois autres collections. Les informations obtenues permettent de discuter des processus d’évolution technique sur le temps long, de proposer une vision alternative des peuplements qui considère en particulier l’idée d’inventions du façonnage bifacial indépendantes, et enfin d’envisager des espaces culturels à différentes échelles de temps et d’espace. / The “Out of Africa” model is deeply rooted in the issues of Paleolithic settlement. For the Lower and Early Middle Pleistocene, several waves of early hominid dispersal from Africa have been proposed, especially to the Near East on the basis of three major sites: Dmanisi, ‘Ubeidiya and Gesher Benot Ya‘aqov. This theory also conveys the idea of repeated imports of new techniques, including bifacial shaping.However, the mechanisms inherent in this model are deconstructed: it allows to identify conceptual and methodological obstacles from the “arrow paradigm”, which simplifies and reduces the complexity of technical and cultural phenomena.The absence of space and time in the “Out of Africa” model is a crippling flaw. To reintroduce these dimensions in the debate, an evolutionary view of technics is used and is inspired by thoughts from philosophy, ergonomics and geography. In Paleolithic prehistory, this point of view, developed over past fifteen years, led to work out a techno-functional methodology focused on notions of tool, gesture and functioning.A detailed study using this approach was conducted on four assemblages from East Africa and Near East, with some supplementary observations on three other collections Then a discussion is offered on various topics: (1) the processes of technical evolution over long time, (2) an alternative vision of settlements, which particularly considers the idea of independent inventions of bifacial shaping, and finally (3) the ability to define cultural spaces on different scales of time and space.

No description available.

Ce travail a pour objectif de préciser, à travers la composante lithique de cinq gisements, le cadre chrono-culturel des dernières populations de chasseurs-cueilleurs venues occuper le Jura méridional au sortir de la dernière grande glaciation. Normalisée par une réflexion engagée sur le degré de préservation des ensembles archéologiques, l’étude du matériel lithique, menée sous une double perspective technologique et économique, permet d’éclairer les comportements ayant orienté la conduite technique des individus et de discuter la structuration de ces groupes sur un axe synchronique et diachronique s’étendant du 15ème millénaire au 11ème millénaire avant le présent. Ces nouveaux acquis permettent ainsi de redéfinir la place des assemblages sur l’espace jurassien et de contrôler l’hypothèse d’une région carrefour soumise à de multiples influences. / The present thesis is aimed at defining more closely the chronocultural frame of late glacial populations on the basis of lithic artefacts from five sites in the Southern French Jura. Starting from a taphonomic analysis, a techno-economical approach illuminates the variability of individual technological behaviour and finally discusses the particular humain groups on a synchronic and diachronic axis from 15.000 untill 11.000 yr B.P. These new results permit to redefine the place of these assemblages in the context of the Jura mountains and thus to establish the Southern French Jura within the Rhine-Saone-Rhone area as a crossing point of multiple influences.

En Colombie, la prépondérance de l’hydroélectricité comme principale source d’énergie électrique a normalement été expliquée par la richesse hydrique du pays et justement, par la « rentabilité » de sa production par rapport à d’autres sources d’énergie. Cependant, cette recherche vise à contester ces idées préconçues. Mon argument principal est qu’il est nécessaire d’explorer le caractère politique et relationnel de cette ressource pour comprendre son importance au sein du secteur de l’énergie électrique. Pour ce faire, j’explore les causes et les effets de la crise énergétique de 1992, bien connue comme El gran apagón (la grande panne). Je montre comment cette crise a été instrumentalisée afin de négocier les techno-politiques du secteur ainsi que ses infrastructures. Soit dans l’implémentation des politiques néolibérales qui émergeaient dans les années 1990 et dans la légitimation de nouveaux barrages hydroélectriques. Dans le cas présent, le barrage hydroélectrique Porce II, situé dans le département d’Antioquia. L’objectif est de mettre en évidence comment les discours de crise et de rareté (mais aussi les discours d’abondance) de l’hydroélectricité ont permis sa prolifération, et par conséquent la transformation massive de certains territoires. Tout en discutant comment ces discours ne sont ni neutres ni statiques dans le temps et dans l’espace. À partir des perspectives de l’écologie politique et des études de la Science et des technologies, je m’attarde sur les effets des discours d’experts et des représentations dominantes de l’eau et de l’hydroélectricité afin de voir comment ils jouent un rôle dans la configuration le secteur de l’énergie électrique entre 1940 et 2000. La crise de El gran Apagón s’avère intéressante dans la mesure elle met en lumière comment ces représentations, mais aussi les pratiques, modèles de gestion et la gouvernance du secteur sont mises en dispute dans ce contexte. Dans la trajectoire historique de l’hydroélectricité en Colombie, cette étude voit comment ces infrastructures sont légitimées non seulement des promesses contradictoires de développement et de progrès, mais aussi par les discours crises. / In Colombia, the predominance of hydropower over other sources of energy have generally been explained by the notion of water abundance in the territory and therefore because of the rentability of its production. Nevertheless, this research aims to question these given ideas. I argue that it is necessary to explore the political and relational nature of this resource to understand its importance in the national electric sector. To do so, I explore the causes and effects of the 1992 energetic crisis, well-know as El gran apagón (The Great Blackout). I put into evidence how this crisis happened to be instrumentalized to negotiate the techno-politics and infrastructures that shape the electric sector system. More precisely, in the processes of implementation of neoliberal politics and in the legitimization of the construction of new dams. In this case, Porce II dam situated in the department of Antioquia. The main goal of this study is to reveal how crisis and scarcity discourses (as much as abundance discourses) of hydroelectricity allowed its proliferation, and thus, massive transformations of several territories in the country. Discussing at the same time how these discourses aren’t neutral nor static through space and time. From political ecology and Science and technology studies perspectives, I pay attention on the effects of expert discourses and representations of hydropower and water to see how they have shaped the electric sector in the period between 1940 and 2000. The crisis of El grand Apagón proves to be interesting as it allows to put into light how these representations, but also practices and the governance are contested and negotiated in this context. In the historical trajectory of hydropower in Colombia, this research seeks to explore how infrastructures are not only legitimated by contradictory promises of development and progress, but also by crisis discourses.

This study aims to provide a critical assessment of social networking sites along with the underlying form of rationality propelling such technological innovations. The hypothesis of this study is rooted in the firm conviction that while social networking sites can be regarded as impressive technological achievements, and while there are certainly an array of benefits that can be associated with them, they nevertheless can be perceived as a hegemonic force which surreptitiously undermines the autonomy and freedom of the modern individual. In order to corroborate and augment such an assertion, this study relies primarily on the critical works of Adorno and Horkheimer (1997); Bauman (2003; 2007 & 2013) and Foucault (1977) in order to both investigate and critically evaluate the everyday assumptions typically associated with a technologically enlightened society, techno-scientific rationality and the recent emergence of technological tools such as social networking services. Based upon the findings that have emerged throughout the course of this investigation, it becomes clear to see that there is indeed a dialectical tension inherent to the nature of the various social networking technologies as they currently operate within the 21st century. Such a discovery is primarily based upon the fact that while social networking technologies do inherently possess emancipatory potentialities for the modern individual, they have nevertheless failed to actualise such potentialities due to the following reasons: 1) Social networking technologies have managed to propagate and entrench a powerful sentiment of technological determinism within modern society along with a highly corrosive form of instrumentalized rationality to which all individuals are now required to acquiesce; 2) Such technologies are paradoxically abrogating the possibility of meaningful interpersonal contiguity due to the fact they have managed to commodify the technological culture associated with a digital form of interaction/communication along with the individual making use of such technologies; and 3) In their current format, social networking services are allowing for the objectification, manipulation and exploitation of the online subject to take place in order to pursue and promote an instrumentalized strategy of marketing surveillance and capital accumulation. / MA (Philosophy), North-West University, Potchefstroom Campus, 2015

This study aims to provide a critical assessment of social networking sites along with the underlying form of rationality propelling such technological innovations. The hypothesis of this study is rooted in the firm conviction that while social networking sites can be regarded as impressive technological achievements, and while there are certainly an array of benefits that can be associated with them, they nevertheless can be perceived as a hegemonic force which surreptitiously undermines the autonomy and freedom of the modern individual. In order to corroborate and augment such an assertion, this study relies primarily on the critical works of Adorno and Horkheimer (1997); Bauman (2003; 2007 & 2013) and Foucault (1977) in order to both investigate and critically evaluate the everyday assumptions typically associated with a technologically enlightened society, techno-scientific rationality and the recent emergence of technological tools such as social networking services. Based upon the findings that have emerged throughout the course of this investigation, it becomes clear to see that there is indeed a dialectical tension inherent to the nature of the various social networking technologies as they currently operate within the 21st century. Such a discovery is primarily based upon the fact that while social networking technologies do inherently possess emancipatory potentialities for the modern individual, they have nevertheless failed to actualise such potentialities due to the following reasons: 1) Social networking technologies have managed to propagate and entrench a powerful sentiment of technological determinism within modern society along with a highly corrosive form of instrumentalized rationality to which all individuals are now required to acquiesce; 2) Such technologies are paradoxically abrogating the possibility of meaningful interpersonal contiguity due to the fact they have managed to commodify the technological culture associated with a digital form of interaction/communication along with the individual making use of such technologies; and 3) In their current format, social networking services are allowing for the objectification, manipulation and exploitation of the online subject to take place in order to pursue and promote an instrumentalized strategy of marketing surveillance and capital accumulation. / MA (Philosophy), North-West University, Potchefstroom Campus, 2015

Published Article / This study investigates the use of off-grid micro-hydrokinetic river system as a cost-effective and sustainable electricity supply option for remote rural residents in close proximity to flowing water and not having access to grid electricity. This hydrokinetic technology is still in the development stage and there is a lack of application especially in rural areas with reasonable water resource. This study will present the economic and environmental benefits of the proposed system. A mathematical model is developed to simulate the system performance as submitted to different solicitations. A test prototype will also be used in order to validate the simulation results.

Current concentrated solar power plants (CSP) use molten salt at 565°C as a heat transfer and energy storage fluid. Due to thermal energy storage (TES), these solar plants can deliver dispatachable electricity to the grid; however, the levelized cost of electricity (LCOE) for these plants is 12-15 c/kWh, about 2.5 times as high as fossil fuel electricity generation. Molten salt technology limits peak operating temperatures to 565°C and a heat engine efficiency of 40%. Liquid metal (LM), however, can reach >1350°C, and potentially utilize a more efficient (60%) heat engine and realize cost reductions. A 1350 °C LM-CSP plant would require ceramic containment, inert atmosphere containment, additional solar flux concentration, and redesigned internal receiver. It was initially unclear if these changes and additions for LM-CSP were technically feasible and could lower the LCOE compared to LS-CSP. To answer this question, a LM-CSP plant was designed with the same thermal input as a published LS-CSP plant. A graphite internal cavity receiver with secondary concentration heated liquid Sn to 1400°C and transferred heat to a 2-phase Al-Si fluid for 9 hours of thermal energy storage. Input heat to the combined power cycle was 1350°C and had 60% thermal efficiency for a gross output of 168 MW. The cost of this LM-CSP was estimated by applying material cost factors to the designed geometry and scaling construction costs from published LS-CSP estimates. Furthermore, graphite was experimentally tested for reactivity with liquid Sn, successful reaction bonds, and successful mechanical seals. The result is switching to molten metal can reduce CSP costs by 30% and graphite pipes, valves, and seals are possible at least at 400°C.

Denna uppsats undersöker ravekulturens nuvarande tillstånd i Stockholm. Ravekulturens primära produkt – den elektroniska musiken (EDM) – som innefattar många olika typer av musikstilar, bland annat techno- och housemusik, har blivit ett allt vanligare inslag inom de reglerade klubb- och festivalverksamheterna. Sedan ravekulturens storhetstid på 1990-talet har rave- och klubbkulturen utvecklats till ett internationellt, om inte globalt, fenomen med demografiska skillnader i förhållande till narkotikabruk, musik- och danstraditioner. Genom Durkheims ritualteori, tillsammans med Collins teori om gruppinteraktion närmas ravekulturen och dess relation till narkotikabruk. Respektive teoretikers begrepp; collective effervescense och emotionell energi, används som verktyg för att erhålla en större förståelse för ravekulturens utveckling och nuvarande läge. För skapa en förståelse av ravekulturens utveckling och nuvarande tillstånd har ett antal nyckelaktörer identifierats, vilka alla besitter stor erfarenhet av ravekulturen. Deras erfarenheter lyfts fram genom semistrukturerade expertintervjuer. Beröringspunkter intervjuerna emellan, samt till teorin har lyfts fram som teman till analysen. Intervjudeltagarna beskriver en ravekultur som i allra högsta grad är levande som har tydliga kopplingar till narkotikabruk, med ecstasy som den primära ravedrogen. Den emotionella energin som skapas på ravens dansgolv lyfts fram som den fundamentala dragningskraft till rave, vilket binder dess deltagare samman genom att etablera ett kollektivt fokus på dansen. Narkotikabruket används som en förstärkare för de gemensamma känslorna, och upprätthåller dansen genom hela nätter. Ravets sociala regler ställs upp för att enskilda deltagare inte ska kunna bryta det kollektiva fokuset genom att ta för stort individuellt utrymme i den sociala sfären. Detta fokus kan också förklara en DJ eller en narkotikalangares särställning inom kulturen eftersom deras roller förstärker fokus genom musiken eller försäljning av narkotika. Det att förklara ravekulturens beståndsdelar utifrån ravets emotionella energi.