160 research outputs found
Distinguishing damages from two earthquakes âArchaeoseismology of a Crusader castle (Al-Marqab citadel, Syria)
Damages from two major earthquakes are identified in medieval Al-Marqab citadel (Latin: Margat) in coastal Syria. Built by the Order of St. John (Hospitallers) in the twelfthâthirteenth centuries, the hilltop fortification has masonry walls made with and without mortar, using the opus caementum technology (Roman concrete). V-shaped and U-shaped failures, single-corner and symmetrical corner collapses, and in-plane shifts of ashlar masonry walls are identified and dated by historical and archaeological methods. The azimuth of displacement is NE-SW for the older
damages of the Crusader period (A.D. 1170â1285), possibly related to the A.D. 1202 earthquake. A later, NW-SE displacement occurred during the Muslim period (post-
1285). The 1202 earthquake produced at least VIII intensity on the MSK scale at Al-Marqab, which is higher than previously considered
al-Marqab kutatåsi program - a történeti forråsok = al-Marqab Research Project - the Historical Sources
Az al-Marqab törtĂ©neti forrĂĄsait vizsgĂĄlĂł kutatĂĄs a tĂ©rsĂ©g egyik legnagyobb keresztes erĆdĂtĂ©sĂ©ben öt Ă©ve folyĂł magyar vezetĂ©sƱ multidiszciplinĂĄris kutatĂĄsi program egyik legfontosabb pillĂ©rĂ©t alkotta. A rĂ©gĂ©szeti Ă©s mĂĄs tudomĂĄnyos kutatĂĄsi mĂłdszerekkel kiegĂ©szĂtett forrĂĄskutatĂĄs rĂ©vĂ©n megtörtĂ©nt a vĂĄr helyisĂ©geinek azonosĂtĂĄsa Ă©s az azokban feltĂĄrt rĂ©gĂ©szeti emlĂ©kanyag tanulmĂĄnyozĂĄsa rĂ©vĂ©n teljesebb kĂ©pet kapni a közĂ©pkori Ă©letrĆl Ă©s technolĂłgiĂĄrĂłl, mely bizonyos esetekben (pl. a vĂzgazdĂĄlkodĂĄs vagy a hadiĂ©pĂtĂ©szeti elemek) meghaladta a korĂĄbban e tĂ©ren fejlettebbnek hitt muszlim vilĂĄg technikai szĂnvonalĂĄt is. Az egyĂ©b terĂŒleteken (pl. falkĂ©pek, Ă©tkezĂ©sâŠstb) vĂ©gzett munkĂĄk eddigi eredmĂ©nyeibĆl kitƱnik, hogy bĂĄr a Szentföld fontos terĂŒlete volt a kulturĂĄlis kölcsönhatĂĄsnak, a latin ĂĄllamok egyik legfontosabb tĂĄmaszpontjĂĄnak lakĂłi erĆsen ragaszkodtak az eurĂłpai gyökerekhez Ă©s tradĂciĂłkhoz. A korabeli eurĂłpai technikai szĂnvonalat meghaladĂł ĂșjĂtĂĄsaik jelentĆs rĂ©sze nem közvetlen ĂĄtvĂ©tel volt a környezĆ civilizĂĄciĂłktĂłl, hanem a speciĂĄlis környezet ĂĄltal kivĂĄltott sajĂĄt fejlesztĂ©s, ami esetenkĂ©nt mĂ©g a környezĆ muszlim ĂĄllamok technolĂłgiai fejlettsĂ©gi szintjĂ©t is meghaladta. A kutatĂĄs eredmĂ©nyei egyben jelentĆsen finomĂtjĂĄk a keresztes hĂĄborĂșk korĂĄrĂłl kialakĂtott egyoldalĂșan negatĂv törtĂ©nelmi kĂ©pet is, hiszen al-Marqab 12-13. szĂĄzadi törtĂ©nelme sorĂĄn inkĂĄbb volt a környezĆ vidĂ©k közigazgatĂĄsi központjakĂ©nt Ă©s gazdasĂĄgi motorjakĂ©nt funkcionĂĄlĂł vĂĄros, mint aktĂv katonai központ. | The research of the historical sources concerning al-Marqab formed one of the most important pillars of the Hungarian led multi-disciplinary research program in one of the largest castles of the Near-East. Data derived from the historical sources and supplemented with archaeological and other sources enabled us to identify the functions of the different areas of al-Marqab and the material retrieved from the excavations gave a detailed picture on the medieval life and technology. Research done on other subjects (eg. fresco research, medieval diet) showed that although the Holy Land was an important place of cultural exchange in the contemporary world, its inhabitants were clung strongly to their European roots and traditions. Many of their innovations stimulated by the special environment and exceeding contemporary European technological standards were not copied from the neighbouring civilizations, but were developments of their own. Some of these (eg. water management) even transcended the level of technological knowledge in the Muslim states traditionally seen as superiors to contemporary Europe. Results of this multi-disciplinary research spearheaded by the work on the historical sources can at the same time considerably clarify the usually one sided, negative picture on the age of the Crusades. For most of its 12th and 13th century history al-Marqab was rather the administrative centre and economic motor of the surrounding countryside than an active military centre
In Situ Synthesis of a Wear Resistant Layer on the Surface of Low Carbon Steel produced by Laser Melt Injection Technology
Titanium and his compounds are one of the most frequently used reinforcing particles in iron â ceramic composite materials. These materials will possess special characteristics because they are quenchable, their hardness can be increased by heat treatment and they can be quite easily machined. The point of the technology developed in the Bay ZoltĂĄn Institute of Materials Sciences and Technology is to form the reinforcing layer on the surface of the sample in an in situ way by melting the surface of the low carbon steel and the laminar carbon felt using laser beam while the titanium metal powder is simultaneously added to the melt. Several methods (metallographic examinations, selective area hardness measurements, SEM, and XRD) were applied to answer the questions about the optimal conditions for the in situ synthesis of a wear resistant layer
The three-dimensional carrier-envelope-phase map of focused few-cycle pulsed Gaussian beams
We derive an analytical expression that describes the complete
three-dimensional carrier-envelope phase (CEP) distribution of in the focal
volume of ultrashort pulsed Gaussian beams focused by spherical mirrors or
lenses. The focal CEP map depends on the so-called factor specifying the
frequency-dependence of the beam width of the source few-cycle pulse, on its
chirp and on the small chromatic aberration introduced by a lens without
appreciably distorting or broadening the few-cycle pulse. We show how to tailor
the CEP map of mirror-focused and lens-focused few-cycle pulses in order to
produce negligible transversal and axial CEP variations in specific regions of
the focal volume for phase-sensitive interactions of light with matter taking
place in a volume or on a surface. We propose a quasi-achromatic doublet lens
that can implement in practice these tailored CEP distributions.Comment: 9 pages, 6 figure
KĂ©t földrengĂ©s SzĂriĂĄban â Margat vĂĄrĂĄnak archeoszeizmolĂłgiĂĄja
KĂ©t nagyobb, egymĂĄsra következĆ földrengĂ©s ĂĄltal okozott sĂ©rĂŒlĂ©seket azonosĂtottunk Margat (arabul al-Marqab) keresztes vĂĄrĂĄban, SzĂria tengerparti rĂ©giĂłjĂĄban. A Szent JĂĄnos-lovagrend (johannita lovagok) ĂĄltal a 12â13. szĂĄzadban emelt erĆdĂtmĂ©ny erĆs kĆfalakbĂłl ĂĄll, melyet az opus caementum (rĂłmai beton) technolĂłgiĂĄjĂĄval Ă©pĂtettek. V- Ă©s U-alakĂș falsĂ©rĂŒlĂ©sek, egyoldali Ă©s szimmetrikus sarokomlĂĄsok, valamint a falak megnyĂșlĂĄsa törtĂ©neti Ă©s rĂ©gĂ©szeti mĂłdszerekkel datĂĄlhatĂłak. A keresztes idĆszakra (Kr. u. 1170â1285) datĂĄlt idĆsebb sĂ©rĂŒlĂ©sek ĂK-DNy rezgĂ©s következtĂ©ben keletkeztek, valĂłszĂnƱleg az 1202-es földrengĂ©s következtĂ©ben. Az 1285-ben kezdĆdött muzulmĂĄn uralom idejĂ©n keletkezett sĂ©rĂŒlĂ©sek ĂNy-DK rezgĂ©sirĂĄnyrĂłl tanĂșskodnak. A libanoni Baalbekben kipattant 1202-es földrengĂ©s >VIII MSK intenzitĂĄst eredmĂ©nyezett Margatban; ez magasabb az eddigi feltĂ©telezett Ă©rtĂ©knĂ©l
Extended model for optimizing high-order harmonic generation in absorbing gases
We report on an extended version of the one-dimensional model proposed by Constant et al (1999 Phys. Rev. Lett. 82 1668) to study phase matching of high-order harmonic generation in absorbing and dispersive medium. The model-expanded from zeroth to first order-can be used with media having a pressure profile varying linearly with propagation length. Based on the new formulas, the importance of having a generation medium that ends abruptly with a steep pressure gradient for achieving high flux is highlighted. In addition to further rule-of-thumb guidelines for harmonic-flux optimization, it is shown that having a steep increase of pressure in the beginning of the medium increases harmonic flux, while it also decreases the required medium length to reach the absorption-limited maximum
Phase and polarization changes of pulsed Gaussian beams during focusing and propagation
The main goal of this thesis is to study the phase and polarization-state changes of focused, pulsed Gaussian beams upon focusing and propagation. An important topic of the work is the phase and group velocity of focused beams. Related to these properties, special attention is paid to the carrier-envelope phase variations of focused, pulsed beams in the vicinity of focus. An other appointed goal of this study is to examine the influence of focusing, as a diffraction effect, along with that of beam distortions (truncation, chromatic
aberration, monochromatic aberrations - spherical aberration, astigmatism, coma, curvature of field, distortion) on the phase properties in the focus. A relevant topic assigned for examination is the time-dependent polarization state of short pulses, specifically to investigate if it changes upon focusing and free-space propagation, and if yes, how
The effect of plasma-core induced self-guiding on phase matching of high-order harmonic generation in gases
In this work we numerically study a self-guiding process in which ionization
plays a dominant role and analyze its effect on high-order harmonic generation
(HHG) in gases. Although this type of self-guiding --- termed as plasma-core
induced self-guiding in previous works --- limits the achievable cut-off by
regulating the intensity of the laser beam, it provides favorable conditions
for phase matching, which is indispensable for high-flux gas high-harmonic
sources. To underline the role of self-guiding in efficient HHG, we investigate
the time-dependent phase matching conditions in the guided beam and show how
the spatio-temporally constant fundamental intensity contributes to the
constructive build-up of the harmonic field in a broad photon-energy range up
to the provided cut-off.Comment: 14 pages, 7 figure
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