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Electro-thermal characterization, TCAD simulations and compact modeling of advanced SiGe HBTs at device and circuit level / Caractérisation électrothermique, simulations TCAD et modélisation compacte de transistors HBT en SiGe au niveau composant et circuitD'Esposito, Rosario 29 September 2016 (has links)
Ce travail de thèse présente une étude concernant la caractérisation des effets électrothermiques dans les transistors bipolaires à hétérojonction (HBT) en SiGe. Lors de ces travaux, deux procédés technologiques BiCMOS à l’état de l’art ont été analysés: le B11HFC de Infineon Technologies (130nm) et le B55 de STMicroelectronics (55nm).Des structures de test dédiées ont étés conçues, pour évaluer l’impact électrothermique du back end of line (BEOL) de composants ayant une architecture à un ou plusieurs doigts d’émetteur. Une caractérisation complète a été effectuée en régime continu et en mode alternatif en petit et en grand signal. De plus, une extraction des paramètres thermiques statiques et dynamiques a été réalisée et présentée pour les structures de test proposées. Il est démontré que les figures de mérite DC et RF s’améliorent sensiblement en positionnant des couches de métal sur le transistor, dessinées de manière innovante et ayant pour fonction de guider le flux thermique vers l’extérieur. L’impact thermique du BEOL a été modélisé et vérifié expérimentalement dans le domaine temporel et fréquentiel et aussi grâce à des simulations 3D par éléments finis. Il est à noter que l’effet du profil de dopage sur la conductivité thermique est analysé et pris en compte.Des topologies de transistor innovantes ont étés conçues, permettant une amélioration des spécifications de l’aire de sécurité de fonctionnement, grâce à un dessin innovant de la surface d’émetteur et du deep trench (DTI).Un modèle compact est proposé pour simuler les effets de couplage thermique en dynamique entre les émetteurs des HBT multi-doigts; ensuite le modèle est validé avec de mesures dédiées et des simulations TCAD.Des circuits de test ont étés conçus et mesurés, pour vérifier la précision des modèles compacts utilisés dans les simulateurs de circuits; de plus, l’impact du couplage thermique entre les transistors sur les performances des circuits a été évalué et modélisé. Finalement, l’impact du dissipateur thermique positionné sur le transistor a été étudié au niveau circuit, montrant un réel intérêt de cette approche. / This work is focused on the characterization of electro-thermal effects in advanced SiGe hetero-junction bipolar transistors (HBTs); two state of the art BiCMOS processes have been analyzed: the B11HFC from Infineon Technologies (130nm) and the B55 from STMicroelectronics (55nm).Special test structures have been designed, in order to evaluate the overall electro-thermal impact of the back end of line (BEOL) in single finger and multi-finger components. A complete DC and RF electrical characterization at small and large signal, as well as the extraction of the device static and dynamic thermal parameters are performed on the proposed test structures, showing a sensible improvement of the DC and RF figures of merit when metal dummies are added upon the transistor. The thermal impact of the BEOL has been modeled and experimentally verified in the time and frequency domain and by means of 3D TCAD simulations, in which the effect of the doping profile on the thermal conductivity is analyzed and taken into account.Innovative multi-finger transistor topologies are designed, which allow an improvement of the SOA specifications, thanks to a careful design of the drawn emitter area and of the deep trench isolation (DTI) enclosed area.A compact thermal model is proposed for taking into account the mutual thermal coupling between the emitter stripes of multi-finger HBTs in dynamic operation and is validated upon dedicated pulsed measurements and TCAD simulations.Specially designed circuit blocks have been realized and measured, in order to verify the accuracy of device compact models in electrical circuit simulators; moreover the impact on the circuit performances of mutual thermal coupling among neighboring transistors and the presence of BEOL metal dummies is evaluated and modeled.
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Dispositifs optoélectroniques à base de semi-conducteurs organiques en couches mincesBrunner, Pierre-Louis Marc 08 1900 (has links)
No description available.
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Structure and evolution of basin and petroleum systems within a transformrelated passive margin setting : data-based insights from crust-scale 3D modelling of the Western Bredasdorp Basin, offshore South AfricaSonibare, Wasiu Adedayo 04 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2015. / ENGLISH ABSTRACT: This study investigates the crustal structure, and assesses the qualitative and quantitative impacts of crust-mantle dynamics on subsidence pattern, past and present-day thermal field and petroleum
system evolution at the southern South African continental margin through the application of a
multi-disciplinary and multi-scale geo-modelling procedure involving both conceptual and
numerical approaches. The modelling procedure becomes particularly important as this margin
documents a complex interaction of extension and strike-slip tectonics during its Mesozoic
continental rifting processes. Located on the southern shelf of South Africa, the Western
Bredasdorp Basin (WBB) constitutes the focus of this study and represents the western section of
the larger Bredasdorp sub-basin, which is the westernmost of the southern offshore sub-basins. To
understand the margin with respect to its present-day structure, isostatic state and thermal field, a
combined approach of isostatic, 3D gravity and 3D thermal modelling was performed by integrating
potential field, seismic and well data. Complimenting the resulting configuration and thermal field
of the latter by measured present-day temperature, vitrinite reflectance and source potential data,
basin-scale burial and thermal history and timing of source rock maturation, petroleum generation,
expulsion, migration and accumulation were forwardly simulated using a 3D basin modelling
technique. This hierarchical modelling workflow enables geologic assumptions and their associated
uncertainties to be well constrained and better quantified, particularly in three dimensions.
At present-day, the deep crust of the WBB is characterised by a tripartite density structure (i.e. prerift
metasediments underlain by upper and lower crustal domains) depicting a strong thinning that is
restricted to a narrow E-W striking zone. The configuration of the radiogenic crystalline crust as
well as the conductivity contrasts between the deep crust and the shallow sedimentary cover
significantly control the present-day thermal field of the study area. In all respects, this present-day
configuration reflects typical characteristics of basin evolution in a strike-slip setting. For instance,
the orientations of the deep crust and fault-controlled basin-fill are spatially inconsistent, thereby
indicating different extension kinematics typical of transtensional pull-apart mechanisms. As such,
syn-rift subsidence is quite rapid and short-lived, and isostatic equilibrium is not achieved,
particularly at the Moho level.
Accompanied syn-rift rapid subsidence and a heat flow peak led to petroleum preservation in the
basin since the Early Cretaceous. Two additional post-rift thermal anomalies related to the Late
Cretaceous hotspot mechanism and Miocene margin uplift in Southern Africa succeeded the syn-rift
control on maturation. This thermal maturity of the five mature source rocks culminated in four
main generation and three main accumulation phases which characterise the total petroleum systems
of the WBB. The Campanian, Eocene and Miocene uplift scenarios episodically halted source
maturation and caused tertiary migration of previously trapped petroleum. Petroleum loss related to
the spill point of each trap configuration additionally occurs during the Late Cretaceous-Paleocene
and Oligocene-Early Miocene. The timing and extent of migration dynamics are most sensitive to
the geological scenario that combined faulting, intrusive seal bypass system and facies
heterogeneity. In fact, for models that do not incorporate facies heterogeneity, predicted past and
present-day seafloor leakage of petroleum is largely underestimated. This complex interplay of
generation and migration mechanisms has significant implications for charging of petroleum
accumulations by multiple source rocks. Due to early maturation and late stage tertiary migration,
the syn-rift source rocks particularly Mid Hauterivian and Late Hauterivian source intervals
significantly control the extent of petroleum accumulation and loss in the basin.
Lastly, the modelled 3D crustal configuration and Mezosoic to Cenozoic thermal regime of the
WBB dispute classic uniform lithospheric stretching for the southern South African continental
margin. Rather, this PhD thesis confirms that differential thinning of the lithosphere related to a
transtensional pull-apart mechanism is the most appropriate for accurately predicting the evolution
of basin and petroleum systems of the margin. Also, the presented 3D models currently represent
the most advanced insights, and thus have clear implications for assessing associated risks in basin
and prospect evaluation of the margin as well as other similar continental margins around the world. / AFRIKAANSE OPSOMMING: Hierdie studie ondersoek die korsstruktuur en evalueer die kwalitatiewe en kwantitatiewe impakte
van kors-mantel-dinamika op insinkingspatroon, die termiese veld en petroleumstels evolusie aan
die suidelike Suid-Afrikaanse kontinentale grens, in die hede en die verlede, deur die toepassing van
’n multidissiplinêre en multiskaal-geomodelleringsprosedure wat beide konseptuele en numeriese
benaderings behels. Die modelleringsprosedure veral is belangrik aangesien hierdie kontinentale
grens ’n komplekse interaksie van uitbreidings- en strekkingsparallelle tektoniek gedurende die
Mesosoïese vastelandskeurprosesse daarvan dokumenteer. Omdat dit op die suidelike platvorm van
Suid-Afrika geleë is, maak die Westelike Bredasdorp Kom (WBK) die fokus van hierdie studie uit,
en verteenwoordig dit die westelike deel van die groter Bredasdrop-subkom, wat die verste wes is
van die suidelike aflandige subkomme. Om die grens met betrekking tot sy huidige struktuur,
isostatiese staat en termiese veld te verstaan, is ’n kombinasie benadering bestaande uit isostatiese,
3D-gravitasie- en 3D- termiese modellering gebruik deur potensiëleveld-, seismiese en boorgatdata
te integreer Ondersteunend totot die gevolglike konfigurasie en termiese veld van die laasgenoemde
deur middel van hedendaagse temperatuur, soos gemeet, vitriniet-refleksiekoëffisiënt en bronpotensiaal
data, komskaal-begrawing en termiese geskiedenis en tydsberekening van
brongesteentematurasie, is petroleumgenerasie, -uitwerping, -migrasie en -akkumulasie in die
toekoms gesimuleer deur gebruik te maak van ’n 3D-kommodelleringstegniek. Hierdie hierargiese
modelleringswerkvloei maak dit moontlik om geologiese aannames en hulle geassosieerde
onsekerhede goed aan bande te lê en beter te kwantifiseer, veral in drie dimensies.
In die hede word die diep kors van die WBK gekarakteriseer deur ’n drieledige digtheidstruktuur
(met ander woorde voorrift-metasedimente onderlê deur bo- en benedekors domeine) wat dui op ’n
baie wesenlike verdunning, beperk tot ’n dun O-W-strekkingsone. Die konfigurasie van die
radiogeniese kristallyne kors, sowel as die konduktiwiteitskontraste tussen die diep kors en die vlak
sedimentêre dekking, beheer grotendeels die hedendaagse termiese veld van die studiearea. Hierdie
hedendaagse konfigurasie weerspieël in alle opsigte tipiese eienskappe van kom-evolusie in ’n
skuifskeur omgewing. Byvoorbeeld, Die oriëntasies van die diep kors en verskuiwingbeheerde
komsedimentasie byvoorbeeld is ruimtelik inkonsekwent en dui daardeur op verskillende
ekstensiekinematika, tipies van transtensionale tensiemeganisme. As sulks, is sin-rift-versakking
taamlik vinnig en kortstondig, en word isostatiese ekwilibrium nie by die Moho-vlak, in die
besonder, bereik nie.
Samehangende sin-rift vinnige versakking en hittevloeihoogtepunt het gelei tot petroleum behoud in die kom sedert die vroeë Kryt. Twee bykomende post-rift termiese anomalieë wat verband hou met
die laat Kryt-“hotspot” meganisme en die Mioseense kontinentale grensopheffing in Suidelike
Afrika het die sin-rift-beheer met maturasie opgevolg. Hierdie termiese maturiteit van die vyf
gematureerde brongesteentes het in vier hoofgenerasie- en drie hoofakkumulasie fases, wat die
totaliteit van die petroleumstelsels van die WBK karakteriseer, gekulmineer. Die Campaniese,
Eoseense en Mioseense opheffings senarios het episodies bronmaturasie gestop en tersiêre migrasie
van petroleum wat vroeër opgevang was veroorsaak. Addisioneel vind petroleumverlies gekoppel
aan die spilpunt van elke opvanggebiedkonfigurasie tydens die laat Kryt-Paleoseen en Oligoseenvroeë
Mioseen plaas. Die tydstelling en omvang van migrasiedinamika is die sensitiefste vir die
geologiese scenario wat verskuiwing, seëlomseilingstelsel en fasiesheterogeniteit kombineer.
Trouens, vir modelle wat nie fasiesheterogeniteit inkorporeer nie, is voorspellings van vroeëre en
huidige seebodemlekkasie van petroleum grotendeels onderskattings. Hierdie komplekse
wisselwerking van generasie- en migrasiemeganismes het beduidende implikasies vir die laai van
petroleumakkumulasies deur veelvoudige brongesteentes. Vanweë vroeë maturasie en laatstadiumtersiêre
migrasie, oefen die sin-rift-brongesteentes, veral middel Hauterivium- en laat Hauteriviumbronintervalle,
beduidende beheer oor die omvang van petroleumakkumulasie en -verlies in die
kom uit.
Laastens weerspreek die gemodelleerde 3D-korskonfigurasie en Mesosoïese-tot-Senosoïesetermiese
regime van die WBK ’n klassieke uniforme litosferiese rekking vir die suidelike Suid-
Afrikaanse kontinentale grens. Inteendeel, hierdie PhD-proefskrif bevestig dat ’n differensiële
verdunning van die litosfeer, gekoppel aan ’n transtensiemeganisme, die beste geskik is om ’n
akkurate voorspelling oor die evolusie van kom- en petroleumstelsels van die kontinentale grens
mee te maak. Verder, verteenwoordig die 3D-modelle, wat hier aangebied word, tans die mees
gevorderde insigte, en het hierdie modelle dus duidelike implikasies vir die assessering van
verwante risiko’s in kom- en petroleum teikene valuering van die kontinentale grens, so wel as van
ander soortgelyke kontinentale grense regoor die wêreld.
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Etude du comportement mécanique à l’arrachement de fils multi-filamentaires enrobés dans une matrice cimentaire et influence de l’imprégnation / Study of the mechanical pull-out behaviour of multi-filament yarns embedded in a cementitious matrix and influence of the impregnationAljewifi, Hana 12 December 2011 (has links)
Cette recherche porte sur les fils multifilamentaires de verre utilisés pour renforcer les matériaux à base de ciment. Elle est focalisée sur les interactions mécaniques de ce type de fils, constitués d'un assemblage de milliers de filaments micrométriques, avec un micro-béton et sur le rôle spécifique de l'imprégnation du fil par cette matrice cimentaire. Trois pré-conditionnements des fils ont été employés lors de la fabrication des éprouvettes afin de moduler les conditions d'imprégnation par la matrice cimentaire. L'imprégnation de 5 fils multi-filamentaires par la matrice cimentaire a été caractérisée et les paramètres d'imprégnation ont été définis en s'appuyant sur des observations MEB, ainsi que des essais de porosimétrie au mercure et des essais spécifiques d'écoulement le long du fil enrobé. Des essais classiques d'arrachement de type pull-out ont été utilisés pour la caractérisation mécanique. L'analyse des liens entre les propriétés mécaniques et les paramètres d'imprégnation ont permis de mieux comprendre les micro-mécanismes d'interaction filaments / matrice cimentaire et d'expliquer le comportement macroscopique à l'arrachement. / This research deals with multi-filaments glass yarns used as reinforcement of cement based materials. It focuses on the mechanical interactions of these yarns, made of thousands of micrometric filaments, with a micro-concrete and on the specific part of the impregnation of the yarn by the cementitious matrix. Modulated impregnation conditions of the yarns were obtained by using three different manufacturing processes for the samples preparation. The impregnation of 5 multi-filament yarns by the cementitious matrix has been characterized and physical parameters of impregnation were determined using SEM investigations, mercury intrusion porosity measurements and specific tests of flow all along the embedded yarn. Classical pull-out tests have been used for the mechanical characterisation. The study of the links between the mechanical properties and the physical parameters of impregnation allowed accessing a better understanding of the filaments / cementitious matrix interaction micro-mechanisms, and explaining the macroscopic pull-out behaviour.
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Monitorování vlivu jednotlivých složek vyučovací jednotky tělesné výchovy na tělesnou zdatnost dívek 7. třídy ZŠ / Monitoring of influence of individual segments of a teaching unit on physical education on fitness of girls from seventh of elememntary schoolFloriánová, Linda January 2012 (has links)
Title: Monitoring of influence of individual segments of a teaching unit of physical education on fitness of girls from seventh grade of elementary school. Aim: The aim of the empirical part is to monitor the proportional representation of the motoric activities during the time given in the lessons of physical education of the seventh grade girls, and along with the chosen methods of testing of these individuals, to prove or disprove possible influence of the composition of the P.E. lessons on the chosen segments of their fitness. Methods: Various methods were used for testing the considered sample. These were the standardized motoric tests (intense forward bend when sitting, place-jump with legs together, endurance in a pull-up, hand grip) which investigate the chosen segments of the fitness. Another method used was the bioimpedance which measures the parameters of body composition. The data were recollected quantitatively and the results were also processed quantitatively by means of statistic parameters, such as arithmetic mean, variation span and determinative deviation. Results: From the results of the work emerged that as far as the chosen motoric activities and their influence on the chosen segments of the fitness are concerned, during the time given only the segment of flexibility in...
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STRUCTURE DU BATHOLITE DE FERKESSEDOUGOU (SECTEUR DE ZUENOULA, CÔTE D'IVOIRE) : IMPLICATIONS SUR L'INTERPRETATION DE LA GEODYNAMIQUE DU PALEOPROTEROZOÏQUE D'AFRIQUE DE L'OUEST A 2.1 GaGbele, Ouattara 18 December 1998 (has links) (PDF)
La période à 2.1 Ga du Craton d'Afrique de l'Ouest est une période de production massive de leucogranites. Le batholite de Ferkessédougou (Côte d'Ivoire) est, tant du point de vue de sa localisation, de son extension, que de son histoire dans la littérature géologique, un élément majeur de l'interprétation de la géodynamique du Paléoprotérozoïque. Tour à tour considéré comme un granite de ride augéosynclinale puis un granite typique de collision de type moderne, il n'en demeure pas moins le jalon d'un accident crustal NNE-SSW important du Paléoprotérozoïque : le linéament GFB (Greenville-Ferkessédougou-Bobodioulasso). Son étude et son interprétation s'inscrivent dans le débat sur la validité de la tectonique des plaques à cette période. Par analyse satellitale, nous montrons que ce batholite de 400 km de long sur une cinquantaine de large est en fait constitué d'une grande quantité de plutons adjacents relativement proches pétrographiquement. Le contexte général de son encaissant métavolcanique et/ou métasédimentaire birimien (2.2 Ga à 2.1 Ga) faiblement déformé et épizonal ainsi que l'absence de déformations tangentielles additionnelles traduisent la faiblesse de l'épaississement crustal synchrone de sa genèse. Sa fabrique déterminée par analyse structurale classique et par analyse de susceptibilité magnétique est double. La première "magmatique" est le plus souvent coaxiale, d'orientation et de pendages variables. Elle dessine des trajectoires courbes et traduit la mise en place des plutons. Elle est l'équivalent de ce qui a été rapporté à la déformation D1 autour de granites anciens. La seconde, magmatique à post-solidus, beaucoup mieux réglée, souvent constrictive ou non-coaxiale, est l'image d'un champ de contrainte régional transcurrent qui se rapporte à la déformation D2 classique dans la chronologie du craton birimien. Les plutons du batholite granitique de Ferké sont syntectoniques de cette grande phase de raccourcissement (2.1 Ga à 2.07 Ga) du birimien. Le passage en revue des différents modèles de plutons, l'analyse du secteur SW de la Côte d'Ivoire présentant des dykes granites à deux micas et des faciès métamorphiques de plus haut grade, un survol des formations de l'Imataca au Surinam, ainsi que le bilan de l'analyse structurale, nous amènent à proposer un modèle 3D pour le batholite de Ferké. Il correspondrait à un ensemble de petits plutons de forme laccolithique engagés dans la croûte superficielle entre les métasédiments épizonaux birimiens dits "de bassin", des gneiss et micaschistes probablement d'âge compris entre 2.2 et 2.1 Ga. Ces plutons seraient alimentés par un faisceau de dykes issus de la fracturation par ouverture en pull-apart du bassin sédimentaire SASCA-Bandama-Bobodioulasso. La fusion de la croûte essentiellement de type ceinture verte/TTG (absence de traces de matériel archéen), à la verticale du bassin subsident, aura incorporé du matériel sédimentaire de bassin. L'apport de chaleur nécessaire à la compensation de la faiblesse de l'épaississement aurait été fourni par le jeu décrochant des fractures majeures des pull-aparts. La place nécessaire à la mise en place des plutons exige une montée de ces derniers à la fin de la période extensive à la faveur de multiples cauldron-subsidences. Les conditions et régimes des deux déformations principales impliquent un lapse de temps très court entre la stabilisation de l'ouverture des bassins et leur fermeture. Par ailleurs, la variation du niveau structural du Nord-Est vers le Sud-Ouest, en particulier vers la zone probable de l'équivalent-racine au Vénézuéla-Surinam, montre un approfondissement et le rapprochement d'une croûte archéenne vers le SW alors qu'elle n'était jusqu'à présent reconnue que vers l'Ouest (Guinée, Dorsale de Man) ou soupçonnée vers l'Est au Ghana.
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Community perceptions of emergency response modality (cash and food aid) : a case study of Lundu traditional authority, Chikwawa district, MalawiKapalamula, Elisha Harrison Bickson 08 1900 (has links)
The study assesses community perceptions of emergency response modality (cash
and food aid) on development: a case study of Traditional Authority Lundu in
Chikwawa district, Malawi. This is based on the top down approach which is mostly
common in humanitarian aid, where practitioners perceive this to be the right mode
of aid delivery to affected communities. This research has used mixed methods of
research designs. Participants were purposively and randomly sampled and 193
household heads, 2 focus group discussions and 10 key informants were
interviewed. The results revealed that food aid is the best response modality in the
area. Humanitarian aid enhances community development as it eliminates negative
coping mechanisms. Food aid helps to stabilize commodity prices, improve health
status of affected people and promote continuation of development intervention in
the area. The study recommends that a thorough assessment is required to derive at
a response option and resilient interventions that should be included in humanitarian
response. / Development Studies / M.A. (Development Studies)
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Emigration of South African migrants to Australia and New Zealand : a mixed-method studyMarcantuono, Letitia 01 1900 (has links)
Over the past 30 years South Africa has lost valuable human capital due to high volumes of emigration. South Africa has also seen numerous changes in its political, economic and
social structure specifically in these decades, but little investigation has been done into the
possibility of an association between political, economic and social, as well as personal
factors, and the decision to leave South Africa. This study refers to Lee’s Migration Model
(1966) that was used as a broad theory for migration. The model involves four sets of factors: factors associated with the area of origin, factors associated with the area of destination, intervening obstacles and personal factors. Maslow’s Hierarchy of Needs Theory also explains the personal motivational theory for migration. Lee’s Model of Migration is used to investigate which political, economic, social and personal factors in the area of origin (South Africa) pushed South African emigrants to leave the country. It also investigates which political, economic, social and personal factors in the area of destination (Australia and New Zealand) pulled South African emigrants toward these countries.
This study involved mixed-methods research (Creswell, 2009), thus the data collection
methods were both qualitative and quantitative. The study followed a sequential exploratory strategy in two stages with the qualitative data collection occurring first, followed by a quantitative study – ‘QUALquan’ study. The data are mixed between analysis of the qualitative data and the quantitative data collection (Creswell, 2009:211). The qualitative data collection instruments used in the first stage of the study in 2009, were face-to-face interviews consisting of one focus group and six personal interviews in New Zealand, as well as twelve personal interviews in Australia. In the second stage of the study in 2015, namely the quantitative research, respondents were selected by contacting 17 closed (secured) Facebook groups that were formed for South Africans living either in Australia or New Zealand. There is no alternative sampling frame available since emigrants do not need to declare themselves as migrants on a work visa, furthermore, official documentation is not accessible to the public. A quantitative data collection instrument was administered with an online questionnaire. In the Australian Facebook groups, 137 respondents completed the questionnaire, and in New Zealand Facebook groups, 118 respondents, which adds up to a total of 255 respondents who completed the questionnaire.
The results concluded that South Africa’s governance framework, its infrastructure and legislation acted as political push factors motivating South Africans to emigrate, while an uncertain economy contributed as an economic push factor. Socially, a perception of a limited future and a narcissistic society is what pushed South Africans to emigrate. Personal push factors that drove the emigration decision included, unmet physical, safety, belonging and esteem needs. The political factors that pulled South African emigrants to Australia and
New Zealand involved effective government services and governmental aid. Economic pull factors included economic certainty and a lower cost of living. Social pull factors proved to be familiar circumstances and a better future. Personal pull factors were safety, belonging and self-actualisation needs. This mixed-method approach focussed on the gap to a followup study that was identified in previous individual qualitative and quantitative studies. These results may assist the South African government to take measures that ensures the retention
of highly skilled citizens. / Business Management / M. Com. (Business Management)
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The relationship between entrepreneurial orientation and business performance of youth entrepreneurs in Tshwane Metropolitan MunicipalityKumadeka, Cynthia Mawufemor Afua 02 1900 (has links)
Youth unemployment is one of the key global challenges facing the world today. Statistically, the global youth unemployment rate is 13.1%. Youth entrepreneurship is viewed as a possible solution to youth unemployment. Interestingly, the world has adopted entrepreneurship as a strategic approach to facilitate economic participation among the youth. Youth entrepreneurship has gained importance in recent years in many countries, as a way of fostering employment opportunities, boosting economic competitiveness, and promoting local and regional development.
Youth involvement in entrepreneurship assists in boosting their confidence, achieving economic independence, and alleviating poverty. Some researchers describe entrepreneurial orientation as innovativeness, pro-activeness, risk taking, and competitive aggressiveness. Other researchers see entrepreneurial orientation as being pushed or pulled into entrepreneurship. In this study, push and pull factors to become entrepreneurs were used to determine the entrepreneurial orientation of the respondents.
The objectives of the study were to investigate whether there is a relationship between entrepreneurial orientation and the business performance of youth entrepreneurs in the Tshwane Metropolitan Municipality. A descriptive research design within a quantitative research approach was adopted using online surveys and physical administration of questionnaires. The study used a census method to sample 555 youth entrepreneurs in the Tshwane Metropolitan Municipality. A low response rate was achieved as only 96 respondents fully completed the questionnaires, which were used in the analysis.
The collected data was analysed using the Statistical Package for Social Sciences. The findings of this study revealed that push factors had a significant influence on the business performance of youth businesses in the Tshwane Metropolitan Municipality; whereas there was no statistical evidence to suggest that pull factors predicted the business performance of youth businesses in the study area.
The research found that entrepreneurship among young individuals is essential to enhancing young people’s economic development. The study discovered that most TMM youths were pulled in to starting their own businesses. The research also suggested that, EO could encourage TMM youth entrepreneurs to continue to become innovative, take- risk, be pro-active and competive aggressive in the businesses. / Business Management / M.A (Business Management)
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Přední náprava vysokovýkonného sportovního vozu / Front Axle of a High-performance Sports CarHrudík, Jan January 2011 (has links)
Tato diplomová práce byla psána při studentské zahraniční stáži, pod záštitou Evropské Unie – program „ERASMUS Student Mobility for Placement“. Stáž byla absolvována mezi prosincem 2010 a květnem 2011 ve společnosti a.d.Tramontana, mající sídlo v Palau de Santa Eulália, Španělsko. Pro kompletní návrh podvozku a odpružení jakéhokoli vozidla je nezbytná znalost mnoha technických disciplín. Tato diplomová práce se zabývá dvěma z nich – odpružení a řízení. Nejprve je rozebrána teorie, na kterou se může navázat v praktické části práce. Velká pozornost byla věnována srozumitelnosti textu a názornosti obrázků, bez zbytečných detailů, avšak bez vynechání důležitého. Tuto práci je tedy možné užít jako prvního kroku před návrhem podvozku. V další části je popsáno, jak byla probraná teorie využita při návrhu řízení u skutečného vozu, přičemž největší pozornost je věnována Ackermannově teorii řízení a geometrii zabraňující samořízení při propružení. V závěrečných částech je pozornost věnována ukázce některých z každodenních činností v malosériové výrobě automobilů – jde o zjištění maximálně možného pohybu kola při propružení a proces výroby příčných trojúhelníkových ramen včetně návrhu jejich připevnění k šasi.
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