排序方式： 共有12条查询结果，搜索用时 937 毫秒
1.
César A. Zen Vasconcellos Dimiter Hadjimichef Magno Machado Benno Bodmann Marcelo Netz-Marzola Geovane Naysinger Mariana Vargas Magaña Peter O. Hess Horst Stöcker Steven Gullberg Remo Ruffini 《Astronomische Nachrichten》2024,345(2-3):e240029
We outline our experience in organizing the first edition of the Workshop on Matter, Astrophysics, Gravitation, Ions and Cosmology, held in virtual and in-person format, denominated MAGIC23, held from 6 to 10 March, 2023, in Praia do Rosa, Santa Catarina, Brazil. The event aimed to bring together leading academic scientists, professors, students, and research scholars for exchanging experiences and discuss the most recent innovations, trends, practical challenges, and experimental and theoretical solutions adopted in the investigation fields within the scope of the meeting. The workshop offered to the participants a platform for scientific and academic projects, partnerships, and presentation of high-quality research contributions describing original and unpublished results on topics related to matter, astrophysics, gravitation, ions, and cosmology. 相似文献
2.
Dimiter Yordanov 《Pure and Applied Geophysics》1968,69(1):229-236
Summary Solution of the diffusion equation is obtained for a linear source in the boundary layer with unstable stratification, when the Monin-Obukhov similarity theory is used for the wind profile and coefficient of vertical turbulent exchange. On the basis of the solution obtained numerically calculations are made. 相似文献
3.
Dimiter Yordanov 《Pure and Applied Geophysics》1970,79(1):85-91
Summary The solution of the ionization balance equation is found in the surface air layer at horizontal homogeneity assuming an exponential law for the turbulent diffusion coefficient. Expressions describing the vertical distribution of the small ion concentration are found estimating on their basis the layer height by an electrode effect. A relation is found among the small ion concentration, the electric conductivity and the electric field in the surface layer. 相似文献
4.
Palaeobotanical methods and geochemical techniques were used to assess plant contribution and palaeoenvironment for the Staniantsi Basin, Bulgaria. The aim was to connect palaeovegetation change and climate oscillation based on pollen and statistical analysis with organic geochemical proxies for a Late Miocene lacustrine to paludial sedimentary succession.Three samples from lignite/marl cycles were studied. The biomarker assemblage and bulk chemical data indicated that gymnosperms were not important in the palaeomire. The presence of des-A-triterpenoids, 17,21-seco-triterpenoids, hopanes, a high content of a D-ring monoaromatic hopane, and aromatized triterpenoids suggested that photochemical and microbial processes significantly contributed to the alteration of the organic matter (OM). A prolonged period of high water table and severe mechanical destruction promoted microbial activity prior to burial and enhanced decay. A geochemical appraisal of short term climate oscillation (ca. 21.7 kyr) was attempted within the limitations of the small number of samples studied. The cycles are expressed as lignite/marl-clay layers combined with cyclic changes in swamp vegetation related to cyclic changes in groundwater level and inundation of the basin. In periods of low water level (swamp phase) lignite accumulation took place. Preliminary results for selected samples suggest that the oscillation may be reflected in the content of friedelin vs. possible degradation products. The ratio of a chromatographic peak tentatively assigned as A-norfriedel-8-en-10-one to friedelin is proposed as a means of detecting short term environmental cycles, where values <1 represent the swamp phase and those >1 reflect periods of inundation. However, time-series analysis using densely sampled lignite-clay layer oscillations are needed to confirm the value of this biomarker ratio for environmental reconstruction. 相似文献
5.
Dimiter Yordanov 《Pure and Applied Geophysics》1969,74(1):105-109
Summary The solution about the concentration from a line source in the surface layer under unstable stratification obtained by us in [1]2 is investigated. A physical sense is given to the obtained simple asymptotic representations, determining on the basis of some numerical calculations the region of their applicability too. 相似文献
6.
Dimiter Kisliakov 《地震工程与结构动力学》1990,19(8):1143-1152
The response of an open high-pressure pipeline containing moving liquid to horizontal seismic loading is investigated. The problem of the interaction between the pipe and the liquid inside it is solved after thorough kinematic analysis, involving two-stage application of the Coriolis theorem. The basic axial loading on the pipeline is also taken into account. As a result, the equation of motion of an arbitrary one-span part of the pipeline under seismic loading is obtained. The harmonic balance is used to find the solution. As an illustration to the theory a numerical example is given with the data of a real water power station pressure pipeline under a past earthquake record. 相似文献
7.
Angelina Todorova Dimiter Syrakov Georgi Gadjhev Georgi Georgiev Kostadin G. Ganev Maria Prodanova Nikolai Miloshev Valery Spiridonov Andrej Bogatchev Kiril Slavov 《Earth Science Informatics》2010,3(4):259-282
Three Grid applications from the SEE-GRID-SCI Environmental VO are developed by the Bulgarian project team: Climate Change
Impact on Air Quality (CCIAQ); Multi-scale atmospheric composition modeling (MSACM); Modeling System for Emergency Response
to the Release of Harmful Substances in the Atmosphere (MSERRHSA). The three applications concern problems of significant
socio-economic significance. They are all dedicated to air pollution studies, but address different goals and so face different
problems and requirements. The applications are briefly presented in the paper. Examples of the different applications validations
are given. Some application results are shown and commented. 相似文献
8.
9.
Fridolin Weber Peter O. Hess Benno Bodmann José de Freitas Pacheco Dimiter Hadjimichef Marcelo Netz-Marzola Geovane Naysinger Moisés Razeira César A. Zen Vasconcellos 《Astronomische Nachrichten》2024,345(2-3):e230148
This paper focuses on the implications of a commutative formulation that integrates branch-cutting cosmology, the Wheeler–DeWitt equation, and Hořava–Lifshitz quantum gravity. Building on a mini-superspace structure, we explore the impact of an inflaton-type scalar field on the wave function of the Universe. Specifically analyzing the dynamical solutions of branch-cut gravity within a mini-superspace framework, we emphasize the scalar field's influence on the evolution of the evolution of the wave function of the Universe. Our research unveils a helix-like function that characterizes a topologically foliated spacetime structure. The starting point is the Hořava–Lifshitz action, which depends on the scalar curvature of the branched Universe and its derivatives, with running coupling constants denoted as . The corresponding wave equations are derived and are resolved. The commutative quantum gravity approach preserves the diffeomorphism property of General Relativity, maintaining compatibility with the Arnowitt–Deser–Misner formalism. Additionally, we delve into a mini-superspace of variables, incorporating scalar-inflaton fields and exploring inflationary models, particularly chaotic and nonchaotic scenarios. We obtained solutions for the wave equations without recurring to numerical approximations. 相似文献
10.
Fridolin Weber Peter O. Hess Benno Bodmann José de Freitas Pacheco Dimiter Hadjimichef Marcelo Marzola Geovane Naysinger Moisés Razeira César A. Zen Vasconcellos 《Astronomische Nachrichten》2024,345(2-3):e230152
This article focuses on the implications of the recently developed commutative formulation based on branch-cutting cosmology, the Wheeler–DeWitt equation, and Hořava–Lifshitz quantum gravity. Assuming a mini-superspace of variables, we explore the impact of an inflaton-type scalar field on the dynamical equations that describe the trajectories evolution of the scale factor of the Universe, characterized by the dimensionless helix-like function . This scale factor characterizes a Riemannian foliated spacetime that topologically overcomes the big bang and big crunch singularities. Taking the Hořava–Lifshitz action as our starting point, which depends on the scalar curvature of the branched Universe and its derivatives, with running coupling constants denoted as , the commutative quantum gravity approach preserves the diffeomorphism property of General Relativity, maintaining compatibility with the Arnowitt–Deser–Misner formalism. We investigate both chaotic and nonchaotic inflationary scenarios, demonstrating the sensitivity of the branch-cut Universe's dynamics to initial conditions and parameterizations of primordial matter content. The results suggest a continuous connection of Riemann surfaces, overcoming primordial singularities and exhibiting diverse evolutionary behaviors, from big crunch to moderate acceleration. 相似文献