Thrust tectonics in the Strandja zone : new data from the Dervent Heights, SE Bulgaria

Dervent Heights are one of the least studied parts of the Strandja zone in Bulgaria. Our detailed field studies in the area of the villages of GoIiam and Valcha PoIiana show the need of revision of the earlier models for nappe tectonics in this pari of the Alpine orogenic belt. Two major units could be distinguished in the pre-Cenomanian basement - autochthon and allochthon. The autochthon is built by Variscan high-grade metamorphic rocks and not penetrativelly deformed granitoids. They are covered by low-grade Triassic metasediments. The allochthone consist of phyllite formation with early Paleozoic age, as well as the underlying carbonate and detrital metasediments. These metasediments form a mappable unit here designated as carbonate terrigeneous formation. Field data allow to reconsider the position of the abundant dolomites. It was suggested that they are forming the autochthon, but the field relations are consistent with interpreting them as a part of the carbonate-terigeneous formation. All studied rocks record very low-grade Early Alpine metamorphism (T<3OO-350'). The metasediments of the autochthon as well these of the allochthon display evidence for strong synmetamorphic deformations and because of that primary structures are not preserved. The timing of the emplacement of the allochthon is poorly constrained, but judging from the lack of localization of ductile as well as of brittle deformation along the major contacts it could be suggested that the emplacement was pre- to synmetamorphic

La participación española en SCOAP3: haciendo posible el acceso abierto a publicaciones científicas del área de física de partículas

Que las instituciones científicas o académicas no pueden garantizar el acceso completo a la información científica que se produce y que en gran parte financian y generan, o a la que producen sus homólogos por motivos económicos, es un hecho del que se viene hablando desde hace ya más de una década. La confluencia de varios factores que han conformado el mercado de la información científica tal como hoy lo conocemos -un sector fuertemente monopolístico, con escaso o nulo nivel de competencia y una escalada de costes a ritmos sin sujeción a parámetros de la economía real- ha sido el germen perfecto para ello. Paradójicamente, los desarrollos tecnológicos permitirían un acceso universal e inmediato si el escenario editorial fuera otro. La situación actual pone de manifiesto que el modelo de comunicación científica basado en un sistema editorial preocupado más por los beneficios económicos que por el valor social de la ciencia y su difusión está, si no en crisis, sí al menos en entredicho. El modelo de negocio tradicional basado en el pago de una suscripción que da derecho a la lectura, propio de la era de la información impresa, resulta manifiestamente obsoleto, no sostenible, y no favorece el desarrollo científico, la transferencia de conocimiento sin barreras y la comunicación eficiente de la ciencia.N

Flow characterization of lifted flames in swirling, reacting flows

Swirl stabilized combustors are commonly used in gaseous fueled land-based gas turbines and liquid fueled aerospace combustors to achieve simultaneously high efficiency, low emissions, wide operability limits, and low thermal and mechanical hardware loadings. Flame shape and location are critical to successful design, and are, therefore, the general focus of this work. In premixed swirl combustion aerodynamically stabilized flames are sometimes observed and desirable as they potentially reduce hardware heat loadings. However, their understanding is largely phenomenological and geometry specific. First, aerodynamically stabilized flames are subject to flow perturbations such as a precessing vortex core (PVC), and therefore, this thesis studies how a precessing flow field affects time-averaged quantities such as flame location. Second, in swirling flowfields with no interior time-averaged stagnation point, flames are sometimes aerodynamically stabilized by instantaneous stagnation points created by large scale structures such as the PVC. Since this places the flame in a time-averaged reverse flow, natural questions are what the flame and flow characteristics are at the flame stabilization location, such as flame stretch, and why the flame does not flash back. Experiments in high pressure, multi-phase, hydrocarbon fueled, reacting flows are highly complex, and quantities such as liquid and gas phase fuel distribution, heat release and flowfield are difficult to obtain. Thus, another focus of this work is experimental development to study the internal physics. First, this thesis finds that precession in radial-axial planar measurements can result in the time-averaged stagnation point to be located in a highly negative region of the flow. Since the time-averaged flow field is often used to determine the flame location, these findings indicate that time-averaged treatments may lead to erroneous results. Precession can also alter the general flow field topology by inducing asymmetries and can cause time-averages to converge slower. Second, the local flow field of a flame aerodynamically stabilized by instantaneous stagnation points is characterized using planar velocity and flame location measurements, conditioned using a line-of-sight technique to capture the flame global leading in the imaging plane. The flame stretch is measured, indicating that the stretch the flame experiences has a high dependence on nozzle velocity. However, the scaling is not understood, and further study is proposed. The time-averaged flame stretch is much higher than opposed diffusion flame extinction stretch rate calculations, which also requires further study. Furthermore, the stretch is not correlated strongly with location and flow velocity. Last, a simultaneous stereo-PIV and fuel/OH-PLIF technique is developed using a single PLIF laser (and a PIV laser) to characterize the spray distribution, flame shape and location, and dual phase flow field for two different jet fuels, at pressures from 2 to 5 bar. Two different flame shapes are observed, with a stability behavior different than with gaseous fuel. Furthermore, the flames extends into the annular jet core, a phenomenon not observed in premixed systems, and mentioned as needing verification in the liquid fueled combustion literature.Ph.D

Instanton-induced contributions to structure functions of deep inelastic scattering

We identify and calculate the instanton-induced contributions to deep inelastic scattering which correspond to nonperturbative exponential corrections to the coefficient functions in front of parton distributions of the leading twist.Comment: MPI-Ph/92-89 , LATEX, 15 pages, 3 figures incl. as uu-encoded fil

Ciencia abierta y datos abiertos en el Consorcio Madroño

Se relata la creación del Consorcio Madroño, el proyecto "e-cienciaDatos", el portal investigaM.Ibero-American Science and Technology Education Consortiu

Zirconium alloy powders for manufacture of 3D printed articles used in nuclear power industry

Main methods of zirconium alloy powder synthesis have been reviewed. Powder applications for additive manufacturing were analyzed. Advantages and drawbacks of zirconium powder production and usage have been shown. Hydrogenation/dehydrogenation method was offered for zirconium powder production.Розглянуто основні способи отримання порошків цирконієвих сплавів. Проаналізовано застосування порошків в адитивних виробництвах. Показано переваги та недоліки способів отримання і застосування порошків цирконію. Для виробництва порошків цирконію запропоновано метод гідрування/дегідрування.Рассмотрены основные способы получения порошков циркониевых сплавов. Проанализированы применения порошков в аддитивных производствах. Показаны преимущества и недостатки способов получения и применения порошков циркония. Для производства порошков циркония предложен метод гидрирования/дегидрирования