• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 45
  • 17
  • 8
  • 6
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 104
  • 34
  • 31
  • 30
  • 30
  • 24
  • 16
  • 16
  • 13
  • 13
  • 11
  • 10
  • 9
  • 9
  • 8
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Η λεπτομερής ιζηματολογική-πετρογραφική μελέτη των αποθέσεων του φλύσχη στη Λήμνο σε σχέση με την παλαιογεωγραφική εξέλιξη του Βορείου Αιγαίου στην κατεύθυνση της πιθανής ύπαρξης πεδίων υδρογονανθράκων

Μαραβέλης, Άγγελος 11 January 2010 (has links)
Ο καθορισμός της ηλικίας των ιζημάτων πραγματοποιήθηκε μέσα από την μελέτη ασβεστιτικών νανοαπολιθωμάτων και έδειξε ότι η ιζηματογένεση τους ξεκίνησε στο ανώτερο Ηώκαινο και ολοκληρώθηκε στο κατώτερο Ολιγόκαινο (NP18-NP21b). Επιπλέον, η απόθεση των υποθαλάσσιων ριπιδίων πραγματοποιήθηκε κατά την διάρκεια των βιοζωνών (NP18-NP21b κατά Μartini, 1971) και προηγήθηκε αυτής της απόθεσης της υφαλοκρηπίδας (ΝΡ21b) δείχνοντας μία προοδευτική σχετική πτώση της στάθμης της θάλασσας. Τα αποτελέσματα της έρευνας οργανικής γεωχημείας βασίστηκαν στην μέθοδο πυρόλυσης Rock Eval 6 και δείχνουν ότι οι αποθέσεις των εξωτερικών τμημάτων του ριπιδίου αποτελούν τα πιο ελπιδοφόρα τμήματα του τουρβιδιτικού συστήματος. Η υφαλοκρηπίδα αποτελεί τον σχηματισμό ο οποίος είναι πιθανόν να παρουσιάσει πετρελαϊκό ενδιαφέρον στο μέλλον μιας και βρίσκεται σε ανώριμο στάδιο θερμικής ωριμότητας Η έρευνα της πιθανής ύπαρξης αποθέσεων που μπορούν να αποτελέσουν ρεζερβουάρ αερίων υδρογονανθράκων στη περιοχή μελέτης αλλά και ο προσδιορισμός της ποιότητας τους βασίστηκε στην τεχνική ποροσιμετρίας υδραργύρου και αποκαλύπτει έναν μεγάλο αριθμό δειγμάτων (8), με αξιόλογες τιμές πορώδους και διαπερατότητας. Τα δείγματα αυτά προέρχονται τόσο από τα εσωτερικά όσο και από τα εξωτερικά τμήματα του τουρβιδιτικού συστήματος ενώ η υφαλοκρηπίδα δεν δείχνει να είναι ικανή να αποτελέσει ρεζερβουάρ αερίων υδρογονανθράκων. Ο προσδιορισμός των ιστολογικών παραμέτρων αποκάλυψε ότι πρόκειται για μεσόκοκκους έως πολύ λεπτόκοκκους ψαμμίτες οι οποίοι προέρχονται τόσο από χαμηλής όσο και από υψηλής πυκνότητας τουρβιδιτικά ρεύματα. Το κοκκομετρικό τους μέγεθος δεν παρουσιάζει σημαντική διαφοροποίηση σε σχέση με τα διάφορα περιβάλλοντα και υποπεριβάλλοντα ιζηματογένεσης. Η γεωχημική στην Λήμνο βασίστηκε στην μέθοδο ενεργοποίησης νετρονίων και δηλώνει ένα περιβάλλον ενεργού ηπειρωτικού περιθωρίου ή ενός ηπειρωτικού νησιωτικού τόξου και ένα μικρό βαθμό ανακύκλωσης (recycling) των υπό μελέτη δειγμάτων. Επιπλέον, αποκαλύπτεται η επίδραση μιας μικτής, όξινης και βασικής/υπερβασικής σύστασης, πηγή τροφοδοσίας. Η ασθενή θετική ανωμαλία στο Eu που παρουσιάζουν, εξηγείται μέσα από ιζηματογενείς διεργασίες όπου τα πλαγιόκλαστα είναι συγκεντρωμένα στις άμμους εξαιτίας της ταξιθέτησης. Η πετρογραφία αποκαλύπτει και την συνεισφορά μιας μεταμορφωμένης, ιζηματογενούς αλλά και μαγματικής πηγής τροφοδοσίας Οι ψαμμίτες συγκεντρώνονται στο πεδίο του ανακυκλωμένου ορογενούς. Η προβολή τους στο συγκεκριμένο πεδίο υποδηλώνει μία ζώνη καταβύθισης ως πιθανό γεωτεκτονικό περιβάλλον της περιοχή μελέτης και είναι σε συμφωνία με την γεωχημική έρευνα και την αποκάλυψη ενός γεωτεκτονικού περιβάλλοντος ενεργού ηπειρωτικού περιθωρίου ή ενός ηπειρωτικού νησιωτικού τόξου για την περιοχή μελέτης. Η ανάλυση και η σύνθεση ιζηματολογικών, παλαιορευματικών, γεωχημικών και πετρογραφικών δεδομένων που πραγματοποιήθηκαν στην περιοχή μελέτης υποδηλώνουν ότι κατά την διάρκεια του ανώτερου Ηωκαίνου-κατώτερου Ολιγοκαίνου (NP18-NP21b) η Λήμνος λειτούργησε ως μία λεκάνη ιζηματογένεσης συστολής μπροστά από το μαγματικό τόξο (contracted forearc basin). Έτσι, η περιοχή μελέτης τοποθετείται ανάμεσα στο ενεργό μαγματικό τόξο της ζώνης της Ροδόπης και στο πρίσμα προσαύξησης το οποίο πιθανόν να βρίσκεται στο βόρειο τμήμα του κεντριού Αιγαίου. / Outcrops of both deep-water and shelf sediments were selected for study on Lemnos Island. During this time interval (NP18-Np21b) the study area was characterized by the deposition of submarine fans that overly shelf deposits with this swallowing upward trend to be owed to tectonic activity. The turbidity system is structured by a “basin floor” fan that is presented overlying a “slope” fan and was constructed under the simultaneous interaction of both progradation and aggradation processes. Both “basin floor” and “slope” fans constitute the lower parts of the stratigraphic column in the study area and have been interpreted as parts of a sand-rich submarine fan on the base of slope to basin floor environment. In order to determine the grain-size statistic and hydraulic parameters thirty (30) thin sections were cut perpendicular to bedding and essentially randomly oriented relative to flow direction. Data obtained from this study suggest that samples are consisted of very-fine to medium grained sandstones, are characterized by poor to very good sorting with their greater part consisting of very good, good and fair sorting sandstones. Moreover, derived from both high and low-density turbidity currents. In order to estimate the flow direction, palaeocurrent data were collected from outcrops. The number of measurements from each outcrop ranges from 10 to 15 and there were plotted in rose diagrams showing that the main palaeocurrent direction has a NNE trend. Twenty samples (20) from the Late Eocene- Early Oligocene turbidite and shelf deposits were selected from the Lemnos Island in order to determine the quantity and quality of the organic matter in each one. The total organic carbon content was determined using a LECO C-230 carbon determinator while the quality of the organic matter was evaluated using a common programmed temperature pyrolysis method, called Rock-Eval 6 pyrolysis by BASELINE RESOLUTION INCORPORATION (BRILABS). The results obtained from the research suggest that studied samples have from poor to excellent source rock potential while the shales of the Lemnos sedimentary rocks can be classified principally as secondary source rocks with potentials to generate gas. In order to assess the tectonic setting of the Lemnos Island, NE Greece, major elements and 14 trace elements were determined using a Thermo Jarrell-Ash ENVIRO II ICP plasma mass spectrometer (ICP-OES) while rare earth elements and additional ultra-trace elements were determined using a Perkin Elmer SCIEX ELAN 6000 (ICP-MS). The study suggests an active margin environment. The positive anomaly of Zr that reflects a heavy mineral input and could be considered typical of passive margin environment is owed to reworking and sorting during sediment transfer. Moreover, a mafic/ultramafic source should be considered as the major component controlling both submarine fans and shelf deposition. The determination of porosity and permeability was based on the “mercury porosimetry technique” as has been described by Katz and Thompson (1986, 1987). Data obtained from this technique suggest that although the majority (13) of the sandstone samples is presented having from fair to very good porosity only some samples (8) have fair to very good permeability.
22

Μελέτη των διαφορικών εξισώσεων που περιγράφουν τη δυναμική πληθυσμού γαύρου στο βόρειο Αιγαίο

Χατζησολωμού, Αικατερίνη 03 December 2008 (has links)
- / -
23

Διερεύνηση της επιφανειακής κυκλοφορίας στο Βόρειο Αιγαίο από μετρήσεις του συστήματος Ποσειδών του Ελληνικού Κέντρου Θαλάσσιων Ερευνών

Σπυρόπουλος, Κωνσταντίνος 22 September 2009 (has links)
Στην παρούσα εργασία ερευνώνται δύο σύνολα δεδομένων τεσσάρων μηνών, τρεχουσών μετρήσεων αέρα και ρεύματος, που λαμβάνονται από το σύστημα Poseidon, σε δύο θέσεις στο βόρειο αιγαίο πέλαγος. Οι μελετημένες χρονικές σειρές καλύπτουν τη θερινή εποχή που εκτείνεται την περίοδο από τον Ιούνιο μέχρι το τέλος Σεπτεμβρίου. Τα αποτελέσματα είναι συνεπή στα κύρια χαρακτηριστικά γνωρίσματα της επιφανειακής κυκλοφορίας στο βόρειο αιγαίο πέλαγος που δείχνει τις υψηλές τρέχουσες ταχύτητες μεταξύ Άθου και Λήμνου και την σχεδόν σταθερή βορειοδυτική ροή κοντά στη νοτιοδυτική ακτή του νησιού Λέσβος. Η παρατηρηθείς μεταβλητότητα ροής στην θαλάσσια περιοχή του Άθου συσχετίζεται με την αντικυκλωνική κυκλοφορία της λεκάνης του Άθου που περιγράφεται σε παλαιότερες μελέτες. Η ροή του νερού κοντά στο νησί Λέσβος είναι επίσης σύμφωνα με το σχέδιο κυκλοφορίας του ύδατος του βορείου αιγαίου πελάγους και θεωρείται ως επέκταση του δευτερεύοντος βορείου κατευθυνόμενου ρεύματος. Η έλλειψη συσχετισμού μεταξύ του ανέμου και του ρεύματος για τις δύο τοποθεσίες, δείχνει ότι ο άνεμος δεν ελέγχει το βαροκλινικό χαρακτήρα της επιφανειακής κυκλοφορίας του βορείου Αιγαίου. / Two 4-month, current and wind measurements datasets, obtained by Poseidon network at two locations in the North Aegean Sea are investigated. The studied time series cover the summer season spanning the period from June to the end of September. The results are consistent to the main surface circulation features of the North Aegean Sea indicating high current speeds between Athos and Limnos and an almost steady northwestwards flow near the southwestern coast of Lesvos Island. The observed flow variability in Athos sea area is related with the Athos basin anticyclonic circulation which is described in previous studies. The water flow near Lesvos island is also in accordance with the water circulation pattern of North Aegean Sea and is considered as a northward extension of the Asia Minor current. No correlation between wind and current at both sites verifies the bacoclinic character of the North Aegean surface circulation.
24

Cultural Transition in the Northern Levant during the Early Iron Age as Reflected in the Aegean-style Pottery at Tell Tayinat

Janeway, Brian 19 June 2014 (has links)
Did an invasion of the Sea Peoples cause the collapse of the Late Bronze Age palace-based economies of the Levant, as well as of the Hittite Empire? Renewed excavations at Tell Tayinat in southeast Turkey promise to shed new light on the critical transitional phase of the Late Bronze/Early Iron Age (c. 1200-1000 B.C.), a period which in the Northern Levant has until recently been considered a Dark Age, due in large part to the few extant textual sources relating to its history (Hawkins 2002: 143). Specifically, this thesis is based upon a stylistic analysis of a distinctive painted pottery known as Late Helladic IIIC (LH IIIC) excavated at the site. Its core is comprised of a diachronic study of the Tayinat ceramics tied into a synchronic comparison with sites across the region—the Amuq Valley, the Levantine coast, Anatolia, Cyprus, and the Aegean Sea basin. Two key objectives of the pottery analysis are to discern Aegean stylistic characteristics from those that are local, and to chronologically situate the assemblage on the basis of regional parallels. What precisely was the nature of Iron I occupation at the site? Renewed excavations suggest that a rudimentary village settlement may have been constructed. Were the inhabitants that founded the Iron Age settlement immigrants that originated in areas to the west—Cyprus, Western Asia Minor, or the Greek Mainland—who were in iii search of more hospitable environs to settle? Or were they elements of the indigenous population forced to start anew after the socio-economic disruptions at the end of the Late Bronze Age? Perhaps they comprised a mixed population of both groups? Stylistic analysis of the painted ware would seem to support the third alternative, resulting in a hybrid style that fused Aegean shapes and motifs with local traditions. Did they simply relocate from the ruins of neighboring Tell Atchana (ancient Alalakh) or from other settlements in the Amuq Valley? Perhaps the movements were not en masse, but rather consisted of small elite groups or tradesmen that assimilated into the local economy, the result of a prolonged process of acculturation. The nature and relative amount of LH IIIC pottery in the Tayinat assemblage favors a traditional migration model. This research begins to fill a longstanding lacuna in the Amuq Valley and attempts to correlate with major historical and cultural trends in the Northern Levant and beyond.
25

Cultural Transition in the Northern Levant during the Early Iron Age as Reflected in the Aegean-style Pottery at Tell Tayinat

Janeway, Brian 19 June 2014 (has links)
Did an invasion of the Sea Peoples cause the collapse of the Late Bronze Age palace-based economies of the Levant, as well as of the Hittite Empire? Renewed excavations at Tell Tayinat in southeast Turkey promise to shed new light on the critical transitional phase of the Late Bronze/Early Iron Age (c. 1200-1000 B.C.), a period which in the Northern Levant has until recently been considered a Dark Age, due in large part to the few extant textual sources relating to its history (Hawkins 2002: 143). Specifically, this thesis is based upon a stylistic analysis of a distinctive painted pottery known as Late Helladic IIIC (LH IIIC) excavated at the site. Its core is comprised of a diachronic study of the Tayinat ceramics tied into a synchronic comparison with sites across the region—the Amuq Valley, the Levantine coast, Anatolia, Cyprus, and the Aegean Sea basin. Two key objectives of the pottery analysis are to discern Aegean stylistic characteristics from those that are local, and to chronologically situate the assemblage on the basis of regional parallels. What precisely was the nature of Iron I occupation at the site? Renewed excavations suggest that a rudimentary village settlement may have been constructed. Were the inhabitants that founded the Iron Age settlement immigrants that originated in areas to the west—Cyprus, Western Asia Minor, or the Greek Mainland—who were in iii search of more hospitable environs to settle? Or were they elements of the indigenous population forced to start anew after the socio-economic disruptions at the end of the Late Bronze Age? Perhaps they comprised a mixed population of both groups? Stylistic analysis of the painted ware would seem to support the third alternative, resulting in a hybrid style that fused Aegean shapes and motifs with local traditions. Did they simply relocate from the ruins of neighboring Tell Atchana (ancient Alalakh) or from other settlements in the Amuq Valley? Perhaps the movements were not en masse, but rather consisted of small elite groups or tradesmen that assimilated into the local economy, the result of a prolonged process of acculturation. The nature and relative amount of LH IIIC pottery in the Tayinat assemblage favors a traditional migration model. This research begins to fill a longstanding lacuna in the Amuq Valley and attempts to correlate with major historical and cultural trends in the Northern Levant and beyond.
26

Ροή θερμότητας στη διεπιφάνεια αέρα-θάλασσας στο Αιγαίο Πέλαγος

Παπαδόπουλος, Βασίλης 05 August 2011 (has links)
Στη διατριβή υπολογίζονται μηνιαίες τιμές για κάθε μια από τις τέσσερις συνιστώσες της ροής θερμότητας στη διεπιφάνεια αέρα-θάλασσας σε πέντε σημεία στο Αιγαίο Πέλαγος για το χρονικό διάστημα 2000-2008 με χρήση δεδομένων α) από το δίκτυο πλωτών μετρητικών σταθμών του συστήματος ΠΟΣΕΙΔΩΝ του Ελληνικού Κέντρου Θαλασσίων Ερευνών, β) από τη δορυφορική πλατφόρμα SSM/I και γ) από την Εθνική Μετεωρολογική Υπηρεσία. Οι μηνιαίες τιμές που υπολογίζονται για κάθε μία από τις τέσσερις συνιστώσες της ροής θερμότητας συγκρίνονται με τις αντίστοιχες από ευρέως χρησιμοποιούμενες βάσεις δεδομένων με σκοπό την αξιολόγηση των βάσεων αυτών για την περιοχή του Αιγαίου Πελάγους. Στη συνέχεια χρησιμοποιούνται οι στατιστικά καλύτερες βάσεις για τη διερεύνηση των χαρακτηριστικών της ροής θερμότητας στο Αιγαίο σε βάθος χρόνου. Εξετάζεται η συσχέτιση των συνιστωσών της ροής θερμότητας με γνωστούς και πειραματικούς κλιματικούς δείκτες, με τη μεγάλης κλίμακας ατμοσφαιρική κυκλοφορία και με το πεδίο του υετίσιμου ύδατος σε μια περιοχή που περιλαμβάνει τον ανατολικό Ατλαντικό, την Ευρώπη και τη βόρεια Αφρική. Τέλος εξετάζεται η συνεισφορά και η συμπεριφορά των συνιστωσών στη μεταβλητότητα της ροής θερμότητας μεταξύ αέρα και θάλασσας στο Αιγαίο Πέλαγος καθώς και το πεδίο της ατμοσφαιρικής πίεσης που ευνοεί την εμφάνιση των ακρότατων τιμών της ξεχωριστά για την ψυχρή και τη θερμή περίοδο του έτους. / Monthly mean values for the each one of the four air-sea heat fluxes components are calculated at five sites in the Aegean Sea for the period 2000-2008. For this calculation three different kinds of data are used: a) data from the Greek network of oceanographic buoys of the Hellenic Centre for Marine Research (the POSEIDON system), b) data from the NASA satellite platform SSM/I, and c) data from the Hellenic National Meteorological Service. The calculated monthly mean values are compared with the corresponding values from broadly used data bases in order to investigate the suitability of these data bases for the Aegean Sea. The statistically robust data archives are used to examine the characteristics of the surface fluxes over an extended time period. More specifically, the correlation between the surface heat exchange and several climatic indices, the large scale atmospheric circulation and the total precipitable water are investigated over an extended area covering the eastern part of the Atlantic Ocean, Europe and north Africa. The behavior and the contribution of each air-sea heat fluxes component to surface fluxes variability over the Aegean are also identified. Last, the sea level pressure (SLP) patterns favoring the uppermost and the lowermost air-sea heat budget values are described separately for the cold and for the warm period of the year.
27

The Role of Kin Relations and Residential Mobility During the Transition from Final Neolithic to Early Bronze Age in Attica, Greece

January 2015 (has links)
abstract: This dissertation addresses the role of kinship and residential mobility during the transition from Final Neolithic to Early Bronze Age (ca. 3500 – 2500 BC) in Attica, Greece. It examines descent systems, ancestor formation, and the interplay between biological, social, and spatial structure in mortuary practices. It also evaluates the nature and degree of residential mobility and its potential role in the formation and maintenance of social networks. Archaeological hypotheses on the kin-based structure of formal cemeteries, the familial use of collective tombs, marriage practices and mate exchange, and relocation were tested focusing on the Early Helladic cemetery of Tsepi at Marathon. Tsepi constitutes the earliest formally organized cemetery on the Greek mainland and it has also contributed to enduring debates over the nature of the interaction between the eastern Attic coast and the central Aegean islands. This study integrates osteological, biogeochemical, and archaeological data. Inherited dental and cranial features were used to examine biological relatedness and postmarital residence (biodistance analysis). Biochemical analysis of archaeological and modern samples was conducted to examine the geographic origins of the individuals buried in the cemetery and reconstruct mobility patterns. Osteological and biogeochemical data were interpreted in conjunction with archaeological and ethnographic/ethnohistoric data. The results generally supported a relationship between spatial organization and biological relatedness based on phenotypic similarity at Tsepi. Postmarital residence analysis showed exogamous practices and tentatively supported higher male than female mobility. This practice, along with dietary inferences, could also be suggestive of maritime activities. Biogeochemical analysis showed a local character for the cemetery sample (96%). The common provenance of the three non-local individuals might reflect a link between Tsepi and a single locale. Burial location was not determined by provenance or solely by biological relatedness. Overall, the results point towards more nuanced reconstructions of mobility in prehistoric Aegean and suggest that burial location depended on a complex set of inter-individual relationships and collective identities. The contextualized bioarchaeological approach applied in this study added to the anthropological investigations of social practices such as kin relations (e.g., biological, marital, social kinship) and residential relocation as diachronic mechanisms of integration, adaptation, or differentiation. / Dissertation/Thesis / Doctoral Dissertation Anthropology 2015
28

The Role of Feasting in the Development of Complexity in Minoan Society

Kaiser, Luke Frederic, Kaiser, Luke Frederic January 2016 (has links)
Feasting is one of the most ubiquitous communal activities in the history of humanity. Oftentimes, feasting is accompanied by a substantial amount of material culture that carries intimate details of the activities that took place at these events. In fact, the changes in the material culture of a feast can also inform us as to how society itself was transforming by becoming increasingly insular or shifting toward a more regional sense of identity. One of the established methods of analyzing a feast is through the examination of its ceramic assemblage. The Bronze Age site of Mochlos in East Crete has a well-stratified Early Minoan deposit which has provided me with an opportunity to interpret a number of social, political, and economic intricacies taking place in East Crete as Minoan society approached the palatial system that dominated the Middle and Late Minoan periods. In order to do this, I provide a background to my research, perform a ceramic study of the stratified deposit in question, interpret the results of the analysis, and include a cross-cultural investigation that serves to further enlighten the data from Mochlos. What is most important to take from this study is that Prepalatial society was not without complexity and structure, and, in reality, much of the complexity that we attribute to the palatial social system of the first half of the 2nd millennium BCE can be traced back to the second half of the 3rd millennium BCE.
29

Rights accumulation in the refugee camps in the Aegean Sea : A study of the difference between humanitarianism and justification

Ahlkvist, My January 2022 (has links)
The purpose of this study is to analyze the communication of six different non-governmentalorganizations present in the refugee camps in the Aegean Sea, to understand which problemsthey identify as critical and how the communication may be interpreted in the light of theneeds of the organizations. The second purpose is to review the discrepancy between thehumanitarian perspective and the justification perspective, by applying the theoreticalframework consisting of framing theory and two discourse-theoretical theories on the resultsof the content analysis. According to the non-governmental organizations, the camps do not meet seven of the ninebasic needs identified by Sphere and UNHCR. The material does not provide enoughinformation regarding the last two needs, the right to non-refoulement and accessibility forpeople with disabilities. While the organizations might have an interest in existing, theanalysis shows that the most evident receivers of the reports are political stakeholders and thegeneral public, and the most evident intent is to conduct advocacy and raise awareness. The theoretical analysis shows that the camps cannot be considered justified as theprerequisites for a fair and functioning decision-making process where every individualsubject to the decision is recognized are not fulfilled. Hence, there is a discrepancy betweenthe humanitarian perspective and the justificatory perspective, in which the justificatoryperspective sets higher requirements focusing on equal humanitarian preconditions andpolitical rights, while the humanitarian perspective solely focuses on basic needs fulfillment.
30

Roman Fine Ware Ceramics from Two Surface Scatters in Aegean Thrace: An Analysis of Distribution Patterns

Hartman, Adam January 2020 (has links)
No description available.

Page generated in 0.0277 seconds