cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Expansion of bundles of light rays in the Lemaître -- Tolman models
Creators: name: Krasiński, Andrzej
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The locus of $θ\equiv {k^μ};_μ = 0$ for bundles of light rays emitted at noncentral points is investigated for Lema\^ıtre -- Tolman (L--T) models. The three loci that coincide for a central emission point: (1) maxima of $R$ along the rays, (2) $θ= 0$, (3) $R = 2M$ are all different for a noncentral emitter. If an extremum of $R$ along a nonradial ray exists, then it must lie in the region $R > 2M$. In $2M < R \leq 3M$ it can only be a maximum; in $R > 3M$ both minima and maxima can exist. The intersection of (1) with the equatorial hypersurface (EHS) $\vartheta = π/2$ is numerically determined for an exemplary toy model (ETM), for two typical emitter locations. The equation of (2) is derived for a general L--T model, and its intersection with the EHS in the ETM is numerically determined for the same two emitter locations. Typically, $θ$ has no zeros or two zeros along a ray, and becomes $+ \infty$ at the Big Crunch (BC). The only rays on which $θ\to - \infty$ at the BC are the radial ones. Along rays on the boundaries between the no-zeros and the two-zeros regions $θ$ has one zero, but still tends to $+ \infty$ at the BC. When the emitter is sufficiently close to the center, $θ$ has 4 or 6 zeros along some rays (resp. 3 or 5 on the boundary rays). For noncentral emitters in a collapsing L--T model, $R = 2M$ is still the ultimate barrier behind which events become invisible from outside; loci (1) and (2) are not such barriers.
description: 32 pages, 26 figures. A few typos of version 1 (one in Fig. 11) corrected, first paragraph modified at the request of the referee. The text now matches the published version. A typo in eq. (4.6) of versions 1, 2 and the published paper corrected
Fermion Mass Hierarchies and Flavor Mixing from $T'$ Symmetry
Creators: name: Ding, Gui-Jun
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We construct a supersymmetric model based on $T'\otimes Z_3\otimes Z_9$ flavor symmetry. At the leading order, the charged lepton mass matrix is not diagonal, $T'$ is broken completely, and the hierarchy in the charged lepton masses is generated naturally. Nearly tri-bimaximal mixing is predicted, subleading effects induce corrections of order $λ^2$, where $λ$ is the Cabibbo angle. Both the up quark and down quark mass matrices textures of the well-known U(2) flavor theory are produced at the leading order, realistic hierarchies in quark masses and CKM matrix elements are obtained. The vacuum alignment and subleading corrections are discussed in detail.
description: 31 pages
The effects of periodic wake disturbances on flat-plate turbulent boundary layers
Creators: name: Holland, Robert M.
Publisher: name: University of British Columbia
Year: 2008

description: Compressor and turbine sections of axial flow turbomachines are subject to periodically disturbed flows. The phenomenon is due to upstream blades creating unsteady periodic wakes that interact with the boundary layer and free stream flows about downstream blades. This study modelled these flow conditions, with circular cylinders periodically traversing in front of a turbulent flat plate boundary layer inside a low speed wind tunnel. These cylinder wake disturbances simulated the unsteady flow pattern in the compressor section of an axial flow turbomachine. Both time-averaged and ensemble-averaged data were interpreted in this study. The free stream wake disturbance was found to be similar to simple analytical predictions andthe boundary layer is believed to be responsible for a phase lag of the cylinder wake. The ensemble-averaged turbulence intensity increases dramatically with periodic unsteady flow, causing an increase in local coefficient of friction, boundary layer thickness, momentum thickness, and displacement thickness. Vortices are believed to be the predominant structure in the unsteady cylinder wakes. The vortex structures and turbulence effects tend to break down and dissipate as the flow proceeds downstream. Vortex theory can be used to explain and predict the velocity deficit and phase angle profiles seen in this study.
Σαπφώ: η «μακρινή εξαδέλφη» του Ελύτη
Creators: name: Βερρή, Μαρία Σπυρίδωνος
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Ελύτης
Σαπφώ
λυρική ποίηση, υπερρεαλισμός
Elytis
Sappho
lyric poetry, surrealism

description: Η παρούσα εργασία στοχεύει να παρουσιάσει την ποιητική σχέση του Οδυσσέα Ελύτη με την αρχαία λυρική ποιήτρια Σαπφώ, όπως αυτή εκδηλώνεται κυρίως μέσα από το έργο του Σαπφώ: ανασύνθεση και απόδοση. Για τον λόγο αυτόν, ερευνώ ποια σημεία τονίζονται περισσότερο από τον ποιητή στο παραπάνω βιβλίο του, καθώς εκείνα δείχνουν τόσο τον δρόμο που φαίνεται να ακολούθησε ο Ελύτης προσεγγίζοντας τη Σαπφώ όσο και τον τρόπο που ο ποιητής μοιάζει να προτείνει στον σύγχρονο άνθρωπο, ώστε να γνωρίσει κι εκείνος την αρχαία λυρική ποιήτρια. Έτσι, αρχικά επισημαίνω τη συνειδητή προβολή του πρώτου ενικού προσώπου από τον Ελύτη στο παραπάνω έργο, κυρίως μέσα από την αυτοπαρουσίαση της «Σαπφώς», της ποιητικής persona του βιβλίου. Έπειτα, αναζητώ πώς η φύση της Αιολίδας μπορεί να αποτελέσει τον κοινό χώρο δράσης των δυο ποιητών και τον τόπο, βέβαια, μέσα από τον οποίο ο αναγνώστης μπορεί να επικοινωνήσει με την αρχαία λυρική ποιήτρια. Τέλος, θεωρώντας τη γλώσσα ως τον τρίτο δρόμο που επιλέγει ο Ελύτης για να μας φανερώσει τη Σαπφώ, ερευνώ πώς ο ποιητής έχοντας ως κέντρο εργασίας του τις ιδέες του περί της δυναμικής της λυρικής γλώσσας προχωρεί στην ανασύνθεση και απόδοση των σαπφικών αποσπασμάτων στο παραπάνω έργο του
description: The aim of this study is to present the poetic relation of Odysseus Elytis with the ancient Greek lyric poetess Sappho, as it is demonstrated mainly through his book Sappho: recomposition and rendition. Therefore, I examine which points are mostly stressed by the poet in this book, since those can indicate the path Elytis followed in order to approach Sappho, as well as the manner the poet suggests to the reader so as to get acquainted with the lyric poetess’ work. Thus, I firstly highlight the intentional emphasis of the first-person singular by Elytis mainly through the self-presentation of “Sappho”, the poetic persona of the book. Secondly, I explore how the nature of Aiolida can be the common place of both poets’ poetic action, as well as the locus where the reader can communicate with Sappho. Finally, considering the Greek language as the third medium Elytis opts to use to present us Sappho, I examine by what method the poet recomposes and renders the sapphic verses in his book reflecting on his theory of the power of the lyric word
Insights from snapshot spectroscopic radio observations of a weak Type I noise storm
Creators: name: Mondal, Surajit
name: Oberoi, Divya
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present a high fidelity snapshot spectroscopic radio imaging study of a weak type I solar noise storm which took place during an otherwise exceptionally quiet time. Using high fidelity images from the Murchison Widefield Array, we track the observed morphology of the burst source for 70 minutes and identify multiple instances where its integrated flux density and area are strongly anti-correlated with each other. The type I radio emission is believed to arise due to electron beams energized during magnetic reconnection activity. The observed anti-correlation is interpreted as evidence for presence of MHD sausage wave modes in the magnetic loops and strands along which these electron beams are propagating. Our observations suggest that the sites of these small scale reconnections are distributed along the magnetic flux tube. We hypothesise that small scale reconnections produces electron beams which quickly get collisionally damped. Hence, the plasma emission produced by them span only a narrow bandwidth and the features seen even a few MHz apart must arise from independent electron beams.
description: Accepted for publication in ApJ
Dark Matter Candidate from Conformality
Creators: name: Frampton, P. H.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Abelian quiver gauge theories provide candidates for the conformality approach to physics beyond the standard model which possess novel cancellation mechanisms for quadratic divergences. A $Z_2$ symmetry (R parity) can be imposed and leads naturally to a dark matter candidate which is the Lightest Conformality Particle (LCP), a neutral spin-1/2 state with weak interaction annihilation cross section, mass in the 100 GeV region and relic density of non-baryonic dark matter $Ω_{dm}$ which can be consistent with the observed value $Ω_{dm} \simeq 0.24$.
description: Nine pages latex. Discussion of relic density clarified
Black hole interior from loop quantum gravity
Creators: name: Modesto, Leonardo
Publisher: name: arXiv
Year: 2006
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper we calculate modifications to the Schwarzschild solution by using a semiclassical analysis of loop quantum black hole. We obtain a metric inside the event horizon that coincides with the Schwarzschild solution near the horizon but that is substantially different at the Planck scale. In particular we obtain a bounce of the two-sphere for a minimum value of the radius and that it is possible to have another event horizon close to the r=0 point.
description: 12 pages, 7 figures. Advances in High Energy Physics Volume 2008 (2008), Article ID 459290
Inviscid flow from a slot into a cross stream
Creators: name: Stropky, Dave
Publisher: name: University of British Columbia
Year: 2008

description: The problem of the oblique injection of a secondary stream into a free stream of different total pressure (non-isoenergetic) has practical application in many physical situations such as in the film cooling of gas turbine blades. This thesis describes a new method for predicting inviscid non-isoenergetic flow from an arbitrarily inclined slot into a uniform free stream. In the absence of flow separation the solution depends on three parameters: [i] the slot angle 13, [ii] a parameter, Cpt, describing the difference in total pressure between the free stream and slot fluids, and [iii] the ratio of densities, D, between the two fluids. For given values Cpt and 13, there exists a unique value of M2/D, where M is the ratio of mass flow of the injectant to the main stream. To guide in the development of the present theory, an isoenergetic solution (Cpt=0, D.1) was found using classical theory. Specifically, M –[-1–]),. where, X 0 < X, <1 High curvature of the streamlines near the downstream slot lip produces an unrealistic suction for large slot angles. The addition of source/sink singularities to the model to simulate flow separation improves the results, but adds empiricism to the solution. The present non-isoenergetic procedure uses the dividing streamline to separate the flowfield into two zones; an internal flow region containing the slot fluid and an external flow region containing the free stream fluid. The technique involves finding, by approximate means, the shape of the dividing streamline that satisfies continuity of static pressure between the regions. The boundary conditions at the upstream slot lip were pivotal in finding a unique solution. The results presented here extend previous work to include arbitrary values of f3, Cpt, and D. For a vertical slot, mass flow rates and discharge coefficients obtained from experiments and viscous numerical predictions are compared to present inviscid calculations. The results show good agreement at reasonable Reynolds numbers provided that the separation region is not large. The effects of separation can be included in the present theory by incorporating the approximate shape of the separated flow region, and the results show a significant improvement, especially at higher mass flow ratios and slot angles. Calculated discharge coefficients for lower slot angles do not compare as well with measured values, but this may be due to the differences in geometries used for the comparison. The solution algorithm used in the present problem is quite general, and may be applied to other geometries and flow conditions.
ผลของการปรับสภาพทางชีวภาพต่อความสามารถในการย่อยสลายเริ่มต้นของหญ้าเนเปียร์ปากช่อง 1
Creators: name: พฤกษ์ อักกะรังสี
Publisher: name: กองบริหารการวิจัย
Year: 2564
Subjects: ลิกโนเซลลูโลส
เซลลูโลส
เฮมิเซลลูโลส
ลิกนิน
น้ําหนักที่สูญเสีย

description: วารสารวิทยาศาสตร์และเทคโนโลยี, 29, 5, 893-903
Transport of interface states in the Heisenberg chain
Creators: name: Michoel, Tom
name: Nachtergaele, Bruno
name: Spitzer, Wolfgang
Publisher: name: arXiv
Year: 2007
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We demonstrate the transport of interface states in the one-dimensional ferromagnetic Heisenberg model by a time dependent magnetic field. Our analysis is based on the standard Adiabatic Theorem. This is supplemented by a numerical analysis via the recently developed time dependent DMRG method, where we calculate the adiabatic constant as a function of the strength of the magnetic field and the anisotropy of the interaction.
description: minor revision, final version; 13 pages, 4 figures
Nuclear Effects in Deep Inelastic Scattering of Charged-Current Neutrino off Nuclear
Creators: name: ChunGui, Duan
name: GuangLie, Li
name: PengNian, Shen
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Nuclear effect in the neutrino-nucleus charged-Current inelastic scattering process is studied by analyzing the CCFR and NuTeV data. Structure functions $F_2(x,Q^2)$ and $xF_3(x,Q^2)$ as well as differential cross sections are calculated by using CTEQ parton distribution functions and EKRS and HKN nuclear parton distribution functions, and compared with the CCFR and NuTeV data. It is found that the corrections of nuclear effect to the differential cross section for the charged-current anti-neutrino scattering on nucleus are negligible, the EMC effect exists in the neutrino structure function $F_2(x,Q^2)$ in the large $x$ region, the shadowing and anti-shadowing effect occurs in the distribution functions of valence quarks in the small and medium $x$ region,respectively. It is also found that shadowing effects on $F_2(x,Q^2)$ in the small $x$ region in the neutrino-nucleus and the charged-lepton-nucleus deep inelastic scattering processes are different. It is clear that the neutrino-nucleus deep inelastic scattering data should further be employed in restricting nuclear parton distributions.
description: 24 pages, 5 figures
Multi-scale characterization of monument limestones
Creators: name: Beck, Kévin
name: Rozenbaum, Olivier
name: Al-Mukhtar, M.
name: Plançon, Alain
Publisher: name: arXiv
Year: 2006
Subjects: subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences

description: Among the parameters influencing stone deterioration, moisture and water movements through the pore network are essential. This communication presents differents methods to characterize stones and to determinate the water transfer properties. Results are analysed for two limestones having similar total porosity, but characterized by different pore networks. These different porous systems govern dissimilar water properties.
Η Υπερκαυκασία από την Αστικοδημοκρατική Επανάσταση του 1917 έως την Συνθήκη του Καρς, 13 Οκτωβρίου 1921
Creators: name: Γάππας, Χαράλαμπος Ιώαννη
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Υπερκαυκασία
Αστικοδημοκρατική επανάσταση 1917
Συνθήκη του Καρς 1921
Transcaucasia
Bourgeois Democratic Revolution 1917
Treaty of Kars 1921

description: Σκοπός της παρούσας μεταπτυχιακής εργασίας ήταν να διερευνήσει και να αποτυπώσει τα ιστορικά γεγονότα που έλαβαν χώρα στην περιοχή της Υπερκαυκασίας κατά το τέλος του Πρώτου Παγκοσμίου Πολέμου καθώς και τα πρώτα χρόνια μετά την λήξη του. Μέσα από την αφήγηση και ανάλυση, παρουσιάζονται το ιστορικό και γεωπολιτικό πλαίσιο μέσα στο οποίο οι λαοί του Νοτίου Καυκάσου αποδεσμεύτηκαν από τον έλεγχο της Ρωσικής Αυτοκρατορίας, συνεκρότησαν νέα ανεξάρτητα κράτη(Δημοκρατίες της Γεωργίας, της Αρμενίας και του Αζερμπαϊτζάν), πολέμησαν μεταξύ τους για την εξασφάλιση του απαραίτητου ζωτικού χώρου καθώς και την απελευθέρωση των ομοεθνών τους, συνεθλίβησαν από την πίεση που τους ασκούσαν περιφερειακές και άλλες μεγάλες δυνάμεις, επηρέασαν και επηρεάστηκαν από τις ευρύτερες περιφερειακές εξελίξεις (ρωσικός εμφύλιος πόλεμος, τουρκικό εθνικό απελευθερωτικό κίνημα) και εν τέλει οδηγήθηκαν στο να επανέλθουν στον έλεγχο της, μπολσεβικικής Ρωσίας.
description: The purpose of this postgraduate thesis was to investigate and put forth the historical events that took place in the region of the Transcaucasia at the end of the First World War and the first years after. Through the narrative and analysis, are presented the historical and geopolitical context, in which the peoples of the South Caucasus were released from the control of the Russian Empire, constituted new independent states (Republics of Georgia, Armenia and Azerbaijan), fought in order to secure the necessary living space as well as to liberate their compatriots, crushed by the pressure exerted to them by regional and other major powers, influenced by and affected to wider regional developments (Russian civil war, Turkish national liberation movement) and ultimately return under the control of the Bolshevik Russia.
Spin diode based on a single-wall carbon nanotube
Creators: name: Weymann, I.
name: Barnas, J.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Electronic transport through a single-wall metallic carbon nanotube weakly coupled to one ferromagnetic and one nonmagnetic lead is analyzed in the sequential tunneling limit. It is shown that both the spin and charge currents flowing through such systems are highly asymmetric with respect to the bias reversal. As a consequence, nanotubes coupled to one nonmagnetic and one ferromagnetic lead can be effectively used as spin diodes whose functionality can be additionally controlled by a gate voltage.
Adiabatic Approximation of the Correlation Function in the Density-Functional Treatment of Ionization Processes
Creators: name: Wilken, F.
name: Bauer, D.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: The ionization of a one-dimensional model Helium atom in short laser pulses using time-dependent density functional theory is investigated. We calculate ionization probabilities as a function of laser intensity by approximating the correlation function of the system adiabatically with an explicit dependence on the fractional number of bound electrons. For the correlation potential we take the derivative discontinuity at integer numbers of bound electrons explicitly into account. This approach reproduces ionization probabilities from the solution of the time-dependent Schroedinger equation, in particular the so-called "knee" due to nonsequential ionization.
description: 4 pages, 4 figures, RevTeX4
Το trust ως όχημα για την άσκηση εμπορικής δραστηριότητας. Σύγκριση με τις κεφαλαιουχικές εταιρίες
Creators: name: Γερτζίκης, Κυριάκος Αθανασίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Τrust
Κεφαλαιουχικές εταιρίες
Καθήκοντα διοίκησης
Trust
Corporations
Duties of directors

description: Σκοπός της διπλωματικής ήταν να ρίξει φως στην εμπορική πτυχή του δικαίου των trust και ειδικότερα στα επιχειρηματικά trust, μέσα από την σύγκρισή τους με τις κεφαλαιουχικές εταιρίες. Αν και επισκιασμένα από τις τελευταίες, τα trust συνεχίζουν, ιδίως στις ΗΠΑ, να αποτελούν όχημα για την άσκηση επιχειρηματικής δραστηριότητας σε εξειδικευμένους συνηθώς τομείς της αγοράς. Καταδείξαμε την ιστορική συγγένεια των επιχειρηματικών trust και των κεφαλαιουχικών εταιριών και αναδείξαμε τα χαρακτηριστικά τους εκείνα που τους επιτρέπουν να προσομοιάζουν μορφολογικά και λειτουργικά τις κεφαλαιουχικές εταιρίες. Αξιοποιώντας τα πορίσματα της αμερικανικής πτωχευτικής νομολογίας, διακρίναμε τα επιχειρηματικά trust από τα υπόλοιπα εμπορικά trust που δεν είναι συγκρίσιμα με τις εταιρίες. Τέλος, συγκρίναμε τα καθήκοντα επιμέλειας και πίστης του trustee με εκείνα του διοικητικού συμβουλίου των κεφαλαιουχικών εταιριών.
description: The purpose of the dissertation was to shed light on the commercial aspect of trust law and in particular on business trusts, through their comparison with corporations. Although overshadowed by the latter, trusts continue, especially in the United States, to be a vehicle for doing business in specialized markets. We demonstrated the historical affinity between business trusts and corporations and highlighted the characteristics of trusts that allow them to morphologically and functionally resemble corporations. Utilizing the findings of the American bankruptcy case law, we distinguished business trusts from other commercial trusts that are not comparable to corporations. Finally, we compared the trustee's duties of care and loyalty with those of the board of directors of corporations.
The Interplay Between Collider Searches For Supersymmetric Higgs Bosons and Direct Dark Matter Experiments
Creators: name: Carena, Marcela
name: Hooper, Dan
name: Vallinotto, Alberto
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: In this article, we explore the interplay between searches for supersymmetric particles and Higgs bosons at hadron colliders (the Tevatron and the LHC) and direct dark matter searches (such as CDMS, ZEPLIN, XENON, EDELWEISS, CRESST, WARP and others). We focus on collider searches for heavy MSSM Higgs bosons ($A$, $H$, $H^{\pm}$) and how the prospects for these searches are impacted by direct dark matter limits and vice versa. We find that the prospects of these two experimental programs are highly interrelated. A positive detection of $A$, $H$ or $H^{\pm}$ at the Tevatron would dramatically enhance the prospects for a near future direct discovery of neutralino dark matter. Similarly, a positive direct detection of neutralino dark matter would enhance the prospects of discovering heavy MSSM Higgs bosons at the Tevatron or the LHC. Combining the information obtained from both types of experimental searches will enable us to learn more about the nature of supersymmetry.
description: 22 pages, 28 figures
Ο πόλεμος Ιράν-Ιράκ: η χρήση χημικών όπλων και το ζήτημα της ελεύθερης ναυσιπλοΐας στον Κόλπο
Creators: name: Γιασκουλίδη, Χριστίνα Βασιλείου
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Μέση Ανατολή
Πόλεμος
Χημικά όπλα
Middle East
War
Chemical Weapons

description: Η διπλωματική εργασία έχει ως αντικείμενο τον πόλεμο του Περσικού Κόλπου, ανάμεσα στο Ιράν και το Ιράκ, ο οποίος έλαβε χώρα από το 1980 έως το 1988,τις διεθνείς επεμβάσεις κατά τη διάρκεια αυτού, καθώς και τα επόμενα, του πολέμου, χρόνια. Ο βασικός άξονας της εργασίας θα αποτελεί το ιστορικό του πολέμου, καθώς επίσης η χρήση όπλων μαζικής καταστροφής και το ζήτημα της ελεύθερης ναυσιπλοΐας στον Κόλπο, ένα ζήτημα έντονα επίκαιρο, καθώς η κρίση στον Περσικό Κόλπο σήμερα, αλλά και οι κλιμακούμενες εντάσεις ανάμεσα στην Ουάσιγκτον και την Τεχεράνη κινδυνεύουν να έχουν μεγάλο αντίκτυπο στη διεθνή κοινότητα αλλά και στην παγκόσμια οικονομία. Θα μελετηθεί και θα αναλυθεί ο ρόλος του Οργανισμού Ηνωμένων Εθνών στην περιοχή και κυρίως ο ρόλος των Η.Π.Α., των οποίων η ανάμειξη ήταν και παραμένει μεγάλη στην περιοχή για πάρα περισσότερα από σαράντα χρόνια. Σήμερα, τη στιγμή που γίνονται προσπάθειες να αποφευχθεί ένας πόλεμος μεταξύ του Ιράν και των Η.Π.Α., καθώς οι μεταξύ τους σχέσεις βρίσκονται σε μεγάλη ένταση με τις διπλωματικές μεθόδους να οδηγούν σε αδιέξοδο, τα ζητήματα της ανάπτυξης πυρηνικών όπλων από το Ιράν και της ελεύθερης ναυσιπλοΐας στον Περσικό Κόλπο έχουν μονοπωλήσει το ενδιαφέρον και έχουν κλιμακώσει τις ανησυχίες της διεθνούς κοινότητας και του ΟΗΕ.
description: The thesis focuses on the Gulf War, between Iran and Iraq, which took place from 1980 to 1988, to the events that led to the war, the international interventions during it and the subsequent years of the war. The main points of the thesis are the history of the war, as well as the issue of use of weapons of mass destruction and the issue of free shipping in the Gulf, a very pertinent issue, as the crisis in the Persian Gulf today, but also the escalating tensions between Washington and Tehran is in danger of having a major impact on the international community and the global economy. The role of the United Nations in the region and especially the role of the United States, whose involvement has been and remains strong in the region for more than forty years, will be studied and analyzed. Today, as efforts are being made to avoid a war between Iran and the United States, relations between the two countries are strained and diplomatic methods lead to a stalemate, the issues of Iran's nuclear program and free shipping in the Persian Gulf have monopolized the interest and escalated concerns of the international community and the UN.
Azimuthal equatorial flows in spherical coordinates with discontinuous stratification
Creators: name: Martin, Calin
Publisher: name: arXiv
Year: 2021
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Mathematical Physics (math-ph)
subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences
subject: 35Q31, 35Q35, 35Q86, 35R35, 76E20

description: We are concerned here with an exact solution to the governing equations for geophysical fluid dynamics in spherical coordinates which incorporates discontinuous fluid stratification. This solution represents a steady, purely--azimuthal equatorial flow with an associated free-surface and an interface separating two fluid regions, each of which having its own continuous distribution of density. However, the two density functions do not match along the interface. Following the derivation of the solution we demonstrate that there is a well-defined relationship between the imposed pressure at the free-surface and the resulting distortion of the surface's shape. Moreover, imposing the continuity of the pressure along the interface generates an equation that describes (implicitly) the shape of the interface. Interestingly, it turns out that the interface defining function has infinite regularity.
description: 3 figures
Connection between the Age Distributions of Star Clusters and Field Stars: A First Application to the Small Magellanic Cloud
Creators: name: Chandar, Rupali
name: Fall, S. Michael
name: Whitmore, Bradley C.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present the age distributions for star clusters and individual stars in the Small Magellanic Cloud (SMC) based on data from the Magellanic Clouds Photometric Survey by Zaritsky and collaborators. The age distribution of the SMC clusters shows a steep decline, dN_{cluster}/dt \propto t^{-0.85\pm0.15}, over the period 10^7 < t <10^9 yr. This decline is essentially identical to that observed previously for more massive clusters in the merging Antennae galaxies, and also for lower-mass embedded clusters in the solar neighborhood. The SMC cluster age distribution therefore provides additional evidence for the rapid disruption of star clusters (``infant mortality''). These disrupted clusters deliver their stars to the general field population, implying that the field star age distribution, dN_{fld star}/dt, should have an inverse relation to dN_{cluster}/dt if most stars form initially in clusters. We make specific predictions for dN_{fldstar}/dt based on our cluster disruption models, and compare them with current data available for stars in the SMC. While these data do not extend to sufficiently young ages for a definitive test, they are consistent with a scenario wherein most SMC stars formed in clusters. Future analyses of dN_{fldstar}/dt that extend down to ages of approximately few million years are needed to verify the age relationship between stars residing in clusters and in the field.
description: 4 pages, 2 figures; Astrophysical Journal Letters, in press
Spin precession in inversion-asymmetric two-dimensional systems
Creators: name: Liu, Ming-Hao
name: Chang, Ching-Ray
Publisher: name: arXiv
Year: 2006
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We present a theoretical method to calculate the expectation value of spin in an inversion-asymmetric two-dimensional (2D) system with respect to an arbitrarily spin-polarized electron state, injected via an ideal point contact. The 2D system is confined in a [001]-grown quantum well, where both the Rashba and the Dresselhaus spin-orbit couplings are taken into account. The obtained analytical results allow more concrete description of the spatial behaviors of the spin precession caused by individually the Rashba and the Dresselhaus terms. Applying the calculation on the Datta-Das spin-FET, whose original design considers only the Rashba effect inside the channel, we investigate the possible influence due to the Dresselhaus spin-orbit coupling. Concluded solution is the choice of +-[1+-10], in particular [110], as the channel direction.
description: 4 pages, 2 figures, to be appeared in Journal of Magnetism and Magnetic Materials
The Quest to Understand the Pioneer Anomaly
Creators: name: Nieto, Michael Martin
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The Pioneer 10/11 missions, launched in 1972 and 1973, and their navigation are reviewed. Beginning in about 1980 an unmodeled force of ~ 8 x 10^{-8} cm/s^2 appeared in the tracking data, it later being verified. The cause remains unknown, although radiant heat remains a likely origin. A set of efforts to find the solution are underway: a) analyzing in detail all available data, b) using data from the New Horizons mission, and c) considering an ESA dedicated mission.
description: 12 pages, 7 figures
Secondary Photons from High-energy Protons Accelerated in Hypernovae
Creators: name: Asano, K.
name: Mészáros, P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Recent observations show that hypernovae may deposit some fraction of their kinetic energy in mildly relativistic ejecta. In the dissipation process of such ejecta in a stellar wind, cosmic ray protons can be accelerated up to $\sim 10^{19}$ eV. We discuss the TeV to MeV gamma-ray and the X-ray photon signatures of cosmic rays accelerated in hypernovae. Secondary X-ray photons, emitted by electron-positron pairs produced via cascade processes due to high-energy protons, are the most promising targets for X-ray telescopes. Synchrotron photons emitted by protons can appear in the GeV band, requiring nearby ($<40$ Mpc) hypernovae for detection with GLAST. In addition, air Cherenkov telescopes may be able to detect regenerated TeV photons emitted by electron-positron pairs generated by CMB attenuation of $π^0$ decay photons.
description: Accepted by ApJL
Development of a CNG intensifier for high pressures
Creators: name: Aichinger, Christoph
Publisher: name: University of British Columbia
Year: 2008

description: A CNG intensifier has been designed to compress natural gas from a variable, elevated-pressure storage source (20 - 200 bar) to a constant high discharge pressure (200 bar). The intensifier delivers variable amounts of gaseous fuel (5 - 43 kg/hr) at a maximum required pressure ratio of 10:1 for fueling a heavy duty bus diesel engine which is converted to a gas-diesel engine. Based on a study of alternative intensifier concepts, a single-stage and a two-stage reciprocating crank-shaft driven intensifier prototype was built. The bore and stroke dimensions of both intensifiers are 31.75 mm and 82.55 mm, respectively. The stage volume ratio of the two-stage intensifier is 2.78:1. The performance of the intensifier prototypes was measured at pressure ratios between 6:1 and 12:1 while keeping the discharge pressure constant at 200 bar. Taking into account volumetric efficiency and the need to limit compression temperature for satisfactory life of the elastomer seals, the performance of the intercooled two-stage intensifier prototype proved to be decisively superior, providing volumetric efficiencies of 92 per cent, isentropic efficiencies of 77 per cent and maximum operating temperatures of 120°C with air cooling at design pressure ratio (10:1). A bore-to-valve area ratio of 16:1 or less was found to be adequate to limit the valve flow velocity to Mach numbers less than 0.1. The test results of the proposed two-stage intensifier indicate a potential for efficient intensifier operation at pressure ratios exceeding 10:1. However, the crank-shaft actuation of the intensifier can lead to friction- and alignment-related problems at higher piston frequencies and it is suggested that a variable displacement, hydraulic actuator could be utilized to further improve efficiency and to offer better controlability.
A low-noise on-chip coherent microwave source
Creators: name: Yan, Chengyu
name: Hassel, Juha
name: Vesterinen, Visa
name: Zhang, Jinli
name: Ikonen, Joni
name: Grönberg, Leif
name: Goetz, Jan
name: Möttönen, Mikko
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The scaleup of quantum computers operating in the microwave domain requires advanced control electronics, and the use of integrated components that operate at the temperature of the quantum devices is potentially beneficial. However, such an approach requires ultra-low power dissipation and high signal quality in order to ensure quantum-coherent operations. Here, we report an on-chip device that is based on a Josephson junction coupled to a spiral resonator and is capable of coherent continuous-wave microwave emission. We show that characteristics of the device accurately follow a theory based on a perturbative treatment of the capacitively shunted Josephson junction as a gain element. The infidelity of typical quantum gate operations due to the phase noise of this cryogenic 25-pW microwave source is less than 0.1% up to 10-ms evolution times, which is below the infidelity caused by dephasing in state-of-the-art superconducting qubits. Together with future cryogenic amplitude and phase modulation techniques, our approach may lead to scalable cryogenic control systems for quantum processors.
Η αναζήτηση αχρεωστήτως καταβληθεισών παροχών
Creators: name: Ντεμογιάννης, Αστέριος Ιωάννη
Publisher: name: Aristotle University of Thessaloniki
Year: 2020
Subjects: Κοινωνική ασφάλιση
Αχρεωστήτως καταβληθείσες παροχές
Αναζήτηση
Social Security
Unduly paid benefits
Recovery

description: Σκοπός της παρούσας Μεταπτυχιακής Διατριβής με θέμα «Η αναζήτηση αχρεωστήτως καταβληθεισών παροχών» είναι η μελέτη του συχνού φαινομένου της μετά το πέρασμα πολλές φορές αρκετού χρόνου αξίωσης Φορέων Κοινωνικής Ασφάλισης να τους επιστραφούν από ασφαλισμένους-συνταξιούχους παροχές, οι οποίες τους καταβλήθηκαν σε προηγούμενο διάστημα. Έτσι, αρχικά για την προσέγγιση του θέματος γίνεται μια σύντομη μνεία σε βασικές αρχές του δικαίου της κοινωνικής ασφάλισης, όπως αυτή της χρηστής διοίκησης και της εύνοιας του ασφαλισμένου∙ στη συνέχεια εξειδικεύεται το σε ποιες παροχές αναφέρεται το θέμα, για τις οποίες εκδίδονται συχνότερα καταλογιστικές πράξεις επιστροφής. Ακολούθως, διευκρινίζεται η έννοια της αχρεώστητης καταβολής, με το διαχωρισμό συγκεκριμένων κατηγοριών και περιπτώσεων, στις οποίες μπορεί μια παροχή να αναζητηθεί ανάλογα και με την καλή ή κακή πίστη του λήπτη και σε ποια έκταση και παρατίθενται λεπτομέρειες για την κάθε μία με παραδείγματα παρμένα από τη νομολογία, καθώς και την έκβαση της κάθε απόφασης. Σε επόμενο κεφάλαιο αναλύεται ο τρόπος με τον οποίο ο κάθε ασφαλισμένος-συνταξιούχος μπορεί να αμυνθεί κατά αποφάσεων ΦΚΑ, που διατάσσουν την επιστροφή αχρεωστήτως καταβληθεισών παροχών, καθώς και ειδικά δικονομικά και ουσιαστικά θέματα. Κλείνοντας, κωδικοποιούνται οι σημαντικότερες νομοθετικές διατάξεις, που βρίσκονται σήμερα σε ισχύ και αφορούν το θέμα ανά ΦΚΑ, με πρακτικούς πίνακες, όπου συμπεριλαμβάνονται και εγκύκλιοι των φορέων
description: The purpose of the present Master's Thesis on "The recovery of unduly paid benefits" is to study the frequent occurrence, in which Social Security Institutions claim benefits after a long period of time from insured-retired people, which were paid in previous periods. Thus, first of all, a brief mention is made of the basic principles of social security law, such as good administration and the benefit of the insured; the concept of unduly paid benefits is then clarified, by separating specific categories and cases, in which a benefit can be recovered according to the good or bad faith of the recipient and details are provided for each case with examples taken from case law, as well as the outcome of each court decision. The next chapter analyzes the way in which each insured-retired person can defend himself against SSI decisions, which order the return of unduly paid benefits, as well as special procedural and substantive issues. In conclusion, the most important legislative provisions are being codified, which are currently in force and concern the issue per SSI, with practical tables, which include circulars of the SSI.
A Time-Symmetric Block Time-Step Algorithm for N-Body Simulations
Creators: name: Makino, Junichiro
name: Hut, Piet
name: Kaplan, Murat
name: Saygin, Hasan
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The method of choice for integrating the equations of motion of the general N-body problem has been to use an individual time step scheme. For the sake of efficiency, block time steps have been the most popular, where all time step sizes are smaller than a maximum time step size by an integer power of two. We present the first successful attempt to construct a time-symmetric integration scheme, based on block time steps. We demonstrate how our scheme shows a vastly better long-time behavior of energy errors, in the form of a random walk rather than a linear drift. Increasing the number of particles makes the improvement even more pronounced.
chi_c0 and chi_c2 Decays into eta eta, eta eta', and eta' eta' Final States
Creators: name: Adams, G. S.
name: Collaboration, CLEO
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Using a sample of 3 x 10^6 psi(2S) decays collected by the CLEO III and CLEO_c detector configurations, we present results of a study of χ_{c0} and χ_{c2} decays into eta-eta, eta-etaprime, and etaprime-etaprime final states. We find B(chi_{c0} -> eta-eta)= (0.31+-0.05+-0.04+-0.02)%, B(chi_{c0} -> eta-etaprime) <0.05 % at the 90% confidence level, and B(chi_{c0} -> etaprime-etaprime) = (0.17 +- 0.04 +-0.02 +-0.01)%. We also present upper limits for the decays of χ_{c2} into these final states. These results give information on the decay mechanism of χ_c states into pseudoscalars.
description: 6pages postscript,also available through http://www.lns.cornell.edu/public/CLNS/2006/
Fully differentiable optimization protocols for non-equilibrium steady states
Creators: name: Vargas-Hernández, Rodrigo A.
name: Chen, Ricky T. Q.
name: Jung, Kenneth A.
name: Brumer, Paul
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Chemical Physics (physics.chem-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: In the case of quantum systems interacting with multiple environments, the time-evolution of the reduced density matrix is described by the Liouvillian. For a variety of physical observables, the long-time limit or steady state solution is needed for the computation of desired physical observables. For inverse design or optimal control of such systems, the common approaches are based on brute-force search strategies. Here, we present a novel methodology, based on automatic differentiation, capable of differentiating the steady state solution with respect to any parameter of the Liouvillian. Our approach has a low memory cost, and is agnostic to the exact algorithm for computing the steady state. We illustrate the advantage of this method by inverse designing the parameters of a quantum heat transfer device that maximizes the heat current and the rectification coefficient. Additionally, we optimize the parameters of various Lindblad operators used in the simulation of energy transfer under natural incoherent light. We also present a sensitivity analysis of the steady state for energy transfer under natural incoherent light as a function of the incoherent-light pumping rate.
description: Main work 10 pages and 5 Figures. Supplemental Material 12 pages, 1 Figure, 3 Tables
Universal Fabrication of Two-Dimensional Electron Systems in Functional Oxides
Creators: name: Rödel, Tobias Chris
name: Fortuna, Franck
name: Sengupta, Shamashis
name: Frantzeskakis, Emmanouil
name: Fèvre, Patrick Le
name: Bertran, François
name: Mercey, Bernard
name: Matzen, Sylvia
name: Agnus, Guillaume
name: Maroutian, Thomas
name: Lecoeur, Philippe
name: Felipe~Santander-Syro, Andrés
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Two-dimensional electron systems (2DESs) in functional oxides are promising for applications, but their fabrication and use, essentially limited to SrTiO$_3$-based heterostructures, are hampered by the need of growing complex oxide over-layers thicker than 2~nm using evolved techniques. This work shows that thermal deposition of a monolayer of an elementary reducing agent suffices to create 2DESs in numerous oxides.
description: Main Text + Supporting Information, 25 pages, 11 figures
Resonance-assisted decay of nondispersive wave packets
Creators: name: Wimberger, Sandro
name: Schlagheck, Peter
name: Eltschka, Christopher
name: Buchleitner, Andreas
Publisher: name: arXiv
Year: 2006
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We present a quantitative semiclassical theory for the decay of nondispersive electronic wave packets in driven, ionizing Rydberg systems. Statistically robust quantities are extracted combining resonance assisted tunneling with subsequent transport across chaotic phase space and a final ionization step.
description: 4 pages, 2 figures
SO(10) unified models and soft leptogenesis
Creators: name: Chun, E. J.
name: Velasco-Sevilla, L.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Motivated by the fact that, in some realistic models combining SO(10) GUTs and flavour symmetries, it is not possible to achieve the required baryon asymmetry through the CP asymmetry generated in the decay of right-handed neutrinos, we take a fresh look on how deep this connection is in SO(10). The common characteristics of these models are that they use the see-saw with right-handed neutrinos, predict a normal hierarchy of masses for the neutrinos observed in oscillating experiments and in the basis where the right-handed Majorana mass is diagonal, the charged lepton mixings are tiny. In addition these models link the up-quark Yukawa matrix to the neutrino Yukawa matrix Y^νwith the special feature of Y^ν_{11}-> 0 Using this condition, we find that the required baryon asymmetry of the Universe can be explained by the soft leptogenesis using the soft B parameter of the second lightest right-handed neutrino whose mass turns out to be around 10^8 GeV. It is pointed out that a natural way to do so is to use no-scale supergravity where the value of B ~1 GeV is set through gauge-loop corrections.
description: 26 pages, 2 figures. Added references, new appendix of a relevant fit and improved comments
Iterative methods for overlap and twisted mass fermions
Creators: name: Chiarappa, T.
name: Jansen, K.
name: Nagai, K. -I.
name: Papinutto, M.
name: Scorzato, L.
name: Shindler, A.
name: Urbach, C.
name: Wenger, U.
name: Wetzorke, I.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: We present a comparison of a number of iterative solvers of linear systems of equations for obtaining the fermion propagator in lattice QCD. In particular, we consider chirally invariant overlap and chirally improved Wilson (maximally) twisted mass fermions. The comparison of both formulations of lattice QCD is performed at four fixed values of the pion mass between 230MeV and 720MeV. For overlap fermions we address adaptive precision and low mode preconditioning while for twisted mass fermions we discuss even/odd preconditioning. Taking the best available algorithms in each case we find that calculations with the overlap operator are by a factor of 30-120 more expensive than with the twisted mass operator.
description: 44 pages, 10 figures
Nuclear Modification to Parton Distribution Functions and Parton Saturation
Creators: name: Kang, Zhong-Bo
name: Qiu, Jian-Wei
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We introduce a generalized definition of parton distribution functions (PDFs) for a more consistent all-order treatment of power corrections. We present a new set of modified DGLAP evolution equations for nuclear PDFs, and show that the resummed $α_s A^{1/3}/Q^2$-type of leading nuclear size enhanced power corrections significantly slow down the growth of gluon density at small-$x$. We discuss the relation between the calculated power corrections and the saturation phenomena.
description: 4 pages, to appear in the proceedings of QM2006