448 research outputs found
ΠΡΠΎΠ΅ΠΊΡΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΡΠΈΡΡΠ΅ΠΌΡ ΡΠ»Π΅ΠΊΡΡΠΎΡΠ½Π°Π±ΠΆΠ΅Π½ΠΈΡ Π΄ΠΎΠΌΠΎΡΡΡΠΎΠΈΡΠ΅Π»ΡΠ½ΠΎΠΉ ΠΊΠΎΠΌΠΏΠ°Π½ΠΈΠΈ
ΠΠ±ΡΠ΅ΠΊΡΠΎΠΌ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΡΠ²Π»ΡΠ΅ΡΡΡ ΡΠ΅ΠΌΠΎΠ½ΡΠ½ΠΎ-ΠΌΠ΅Ρ
Π°Π½ΠΈΡΠ΅ΡΠΊΠΈΠΉ ΡΠ΅Ρ
Π΄ΠΎΠΌΠΎΡΡΡΠΎΠΈΡΠ΅Π»ΡΠ½ΠΎΠΉ ΠΊΠΎΠΌΠΏΠ°Π½ΠΈΠΈ. Π¦Π΅Π»ΡΡ ΡΠ°Π±ΠΎΡΡ ΡΠ²Π»ΡΠ΅ΡΡΡ ΡΠ°Π·Π²ΠΈΡΠΈΠ΅ ΠΏΡΠΎΠΌΡΡΠ»Π΅Π½Π½ΠΎΠΉ ΡΠ½Π΅ΡΠ³ΠΎΡΠΈΡΡΠ΅ΠΌΡ. ΠΡΠ½ΠΎΠ²Π½ΡΠ΅ ΠΊΠΎΠ½ΡΡΡΡΠΊΡΠΈΠ²Π½ΡΠ΅, ΡΠ΅Ρ
Π½ΠΈΡΠ΅ΡΠΊΠΈΠ΅, ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΈ ΡΠΊΡΠΏΠ»ΡΠ°ΡΠ°ΡΠΈΠΎΠ½Π½ΡΠ΅ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠΈ: ΠΈΡΡΠ»Π΅Π΄ΡΠ΅ΠΌΡΠΉ Π·Π°Π²ΠΎΠ΄ ΡΠΎΡΡΠΎΠΈΡ ΠΈΠ· ΠΏΡΡΠ½Π°Π΄ΡΠ°ΡΠΈ ΡΠ΅Ρ
ΠΎΠ², Π²ΠΎΡΠ΅ΠΌΡ ΠΈΠ· ΠΊΠΎΡΠΎΡΡΡ
ΠΎΡΠ½ΠΎΡΡΡΡΡ ΠΊ II ΠΊΠ°ΡΠ΅Π³ΠΎΡΠΈΠΈ Π½Π°Π΄Π΅ΠΆΠ½ΠΎΡΡΠΈ ΡΠ»Π΅ΠΊΡΡΠΎΡΠ½Π°Π±ΠΆΠ΅Π½ΠΈΡ; ΠΠ°ΠΏΡΡΠΆΠ΅Π½ΠΈΠ΅ ΠΏΠΈΡΠ°ΡΡΠ΅ΠΉ ΡΠ΅ΡΠΈ 35 ΠΊΠ; Π Π°Π±ΠΎΡΠ΅Π΅ Π½Π°ΠΏΡΡΠΆΠ΅Π½ΠΈΠ΅ Π½Π° ΠΏΡΠ΅Π΄ΠΏΡΠΈΡΡΠΈΠΈ: 10, 0,4 ΠΊΠ; ΠΠΈΡΠ°Π½ΠΈΠ΅ ΡΠ»Π΅ΠΊΡΡΠΎΠΏΡΠΈΠ΅ΠΌΠ½ΠΈΠΊΠΎΠ² ΡΠ΅ΠΌΠΎΠ½ΡΠ½ΠΎ-ΠΌΠ΅Ρ
Π°Π½ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠ΅Ρ
Π° ΠΎΡΡΡΠ΅ΡΡΠ²Π»ΡΠ΅ΡΡΡ ΡΠΌΠ΅ΡΠ°Π½Π½ΠΎΠΉ ΡΠ΅ΡΡΡ ΡΠ»Π΅ΠΊΡΡΠΎΡΠ½Π°Π±ΠΆΠ΅Π½ΠΈΡ.The object of the research is an maintenance shop of a house building factory. The objective of the work is development of an industrial power system. Main constructive, technical, technological and operational characteristic: the studied plant consists of fifteen workshops, eight of them refer to the II power supply reliability category; the feedline voltage is 35 kV; operation voltage in the plant: 10, 0,4 kV; power supply of electrical receivers of the maintenance shop is realized by mixed power supply network
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A JavaScript API for the Ice Sheet System Model: towards on online interactive model for the Cryosphere Community
Abstract. Earth System Models (ESMs) are becoming increasingly complex, requiring extensive knowledge and experience to deploy and use in an efficient manner. They run on high-performance architectures that are significantly different from the everyday environments that scientists use to pre and post-process results (i.e. MATLAB, Python). This results in models that are hard to use for non specialists, and that are increasingly specific in their application. It also makes them relatively inaccessible to the wider science community, not to mention to the general public. Here, we present a new software/model paradigm that attempts to bridge the gap between the science community and the complexity of ESMs, by developing a new JavaScript Application Program Interface (API) for the Ice Sheet System Model (ISSM). The aforementioned API allows Cryosphere Scientists to run ISSM on the client-side of a webpage, within the JavaScript environment. When combined with a Web server running ISSM (using a Python API), it enables the serving of ISSM computations in an easy and straightforward way. The deep integration and similarities between all the APIs in ISSM (MATLAB, Python, and now JavaScript) significantly shortens and simplifies the turnaround of state-of-the-art science runs and their use by the larger community. We demonstrate our approach via a new Virtual Earth System Laboratory (VESL) Web site
ISSM: Ice Sheet System Model
In order to have the capability to use satellite data from its own missions to inform future sea-level rise projections, JPL needed a full-fledged ice-sheet/iceshelf flow model, capable of modeling the mass balance of Antarctica and Greenland into the near future. ISSM was developed with such a goal in mind, as a massively parallelized, multi-purpose finite-element framework dedicated to ice-sheet modeling. ISSM features unstructured meshes (Tria in 2D, and Penta in 3D) along with corresponding finite elements for both types of meshes. Each finite element can carry out diagnostic, prognostic, transient, thermal 3D, surface, and bed slope simulations. Anisotropic meshing enables adaptation of meshes to a certain metric, and the 2D Shelfy-Stream, 3D Blatter/Pattyn, and 3D Full-Stokes formulations capture the bulk of the ice-flow physics. These elements can be coupled together, based on the Arlequin method, so that on a large scale model such as Antarctica, each type of finite element is used in the most efficient manner. For each finite element referenced above, ISSM implements an adjoint. This adjoint can be used to carry out model inversions of unknown model parameters, typically ice rheology and basal drag at the ice/bedrock interface, using a metric such as the observed InSAR surface velocity. This data assimilation capability is crucial to allow spinning up of ice flow models using available satellite data. ISSM relies on the PETSc library for its vectors, matrices, and solvers. This allows ISSM to run efficiently on any parallel platform, whether shared or distrib- ISSM: Ice Sheet System Model NASA's Jet Propulsion Laboratory, Pasadena, California uted. It can run on the largest clusters, and is fully scalable. This allows ISSM to tackle models the size of continents. ISSM is embedded into MATLAB and Python, both open scientific platforms. This improves its outreach within the science community. It is entirely written in C/C++, which gives it flexibility in its design, and the power/speed that C/C++ allows. ISSM is svn (subversion) hosted, on a JPL repository, to facilitate its development and maintenance. ISSM can also model propagation of rifts using contact mechanics and mesh splitting, and can interface to the Dakota software. To carry out sensitivity analysis, mesh partitioning algorithms are available, based on the Scotch, Chaco, and Metis partitioners that ensure equal area mesh partitions can be done, which are then usable for sampling and local reliability methods
Polarization analysis of CuXX-lines emitted from X-pinch
International audienceSoft x-ray emission from CuXX L-shell lines emitted by a dense X-pinch plasma have been investigated with high-resolution curved Bragg crystals at different angles of orientation. Single shot time integrated spectra show clear evidences of polarization for the Ne-like spectral lines 2s22p6 1S0 β 2s22p53s 1P1 (Ξ» = 12.570 Γ
), 2s22p6 1S0 β 2s22p53s 3P1 (Ξ» = 12.8277 Γ
). The variation of the intensity ratio of these two well-separated L-shell lines is discussed in view of its application for suprathermal electron characterization under real experimental conditions of pinch plasmas. We demonstrated that the simultaneous use of two different polarization spectrometers (means 4 Bragg crystals) permitted a high level of confidence for the analysis of the variation of the line ratios due to polarization
Π‘ΡΡΠ΅ΡΡΠ²Π΅Π½Π½ΡΠ΅ ΡΠ°ΠΊΡΠΎΡΡ ΡΠΎΠ²ΡΠ΅ΠΌΠ΅Π½Π½ΠΎΠ³ΠΎ ΠΈ Π±ΡΠ΄ΡΡΠ΅Π³ΠΎ ΡΠΎΡΡΠΎΡΠ½ΠΈΡ Π£ΠΊΡΠ°ΠΈΠ½Ρ
Crash behaviour and light weight have become the major design criteria for car bodies. Modem high strength steels offer appropriate solutions for these requirements. The prediction of the crash behaviour in simulation programs requires the information on materials behaviour during dynamic testing. The reduction of the signal waviness and the inertia effects at strain rates above 50s are major issues in dynamic tensile testing. Damping techniques or load measurement on the sample itself are the common way to reduce oscillations. Strain measurement from the piston displacement or from optical devices on the specimen itself are also compared. Advantages and drawbacks of those various measurement techniques are presented
Future Antarctic bed topography and its implications for ice sheet dynamics
The Antarctic bedrock is evolving as the solid Earth responds to the past and ongoing evolution of the ice sheet. A recently improved ice loading history suggests that the Antarctic Ice Sheet (AIS) has generally been losing its mass since the Last Glacial Maximum. In a sustained warming climate, the AIS is predicted to retreat at a greater pace, primarily via melting beneath the ice shelves. We employ the glacial isostatic adjustment (GIA) capability of the Ice Sheet System Model (ISSM) to combine these past and future ice loadings and provide the new solid Earth computations for the AIS. We find that past loading is relatively less important than future loading for the evolution of the future bed topography. Our computations predict that the West Antarctic Ice Sheet (WAIS) may uplift by a few meters and a few tens of meters at years AD 2100 and 2500, respectively, and that the East Antarctic Ice Sheet is likely to remain unchanged or subside minimally except around the Amery Ice Shelf. The Amundsen Sea Sector in particular is predicted to rise at the greatest rate; one hundred years of ice evolution in this region, for example, predicts that the coastline of Pine Island Bay will approach roughly 45 mm yrβ1 in viscoelastic vertical motion. Of particular importance, we systematically demonstrate that the effect of a pervasive and large GIA uplift in the WAIS is generally associated with the flattening of reverse bed slope, reduction of local sea depth, and thus the extension of grounding line (GL) towards the continental shelf. Using the 3-D higher-order ice flow capability of ISSM, such a migration of GL is shown to inhibit the ice flow. This negative feedback between the ice sheet and the solid Earth may promote stability in marine portions of the ice sheet in the future
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Representation of sharp rifts and faults mechanics in modeling ice shelf flow dynamics: Application to Brunt/Stancomb-Wills Ice Shelf, Antarctica
Ice shelves play a major role in buttressing ice sheet flow into the ocean, hence the importance of accurate numerical modeling of their stress regime. Commonly used ice flow models assume a continuous medium and are therefore complicated by the presence of rupture features (crevasses, rifts, and faults) that significantly affect the overall flow patterns. Here we apply contact mechanics and penalty methods to develop a new ice shelf flow model that captures the impact of rifts and faults on the rheology and stress distribution of ice shelves. The model achieves a best fit solution to satellite observations of ice shelf velocities to infer the following: (1) a spatial distribution of contact and friction points along detected faults and rifts, (2) a more realistic spatial pattern of ice shelf rheology, and (3) a better representation of the stress balance in the immediate vicinity of faults and rifts. Thus, applying the model to the Brunt/Stancomb-Wills Ice Shelf, Antarctica, we quantify the state of friction inside faults and the opening rates of rifts and obtain an ice shelf rheology that remains relatively constant everywhere else on the ice shelf. We further demonstrate that better stress representation has widespread application in examining aspects affecting ice shelf structure and dynamics including the extent of ice mΓ©lange in rifts and the change in fracture configurations. All are major applications for better insight into the important question of ice shelf stability
High-resolution ice-thickness mapping in South Greenland
Airborne radar sounding is difficult in South Greenland because of the presence of englacial water, which prevents the signal from reaching the bed. Data coverage remains suboptimal for traditional methods of ice-thickness and bed mapping that rely on geostatistical techniques, such as kriging, because important features are missing. Here we apply two alternative approaches of highresolution (Μ300 m) ice-thickness mapping, that are based on the conservation of mass, to two regions of South Greenland: (1) Qooqqup Sermia and Kiattuut Sermiat, and (2) Ikertivaq. These two algorithms solve optimization problems, for which the conservation of mass is either enforced as a hard constraint, or as a soft constraint. For the first region, very few measurements are available but there is no gap in ice motion data, whereas for Ikertivaq, more ice-thickness measurements are available, but there are gaps in ice motion data. We show that mass-conservation algorithms can be used as validation tools for radar sounding. We also show that it is preferable to apply mass conservation as a hard constraint, rather than a soft constraint, as it better preserves elongated features, such as glacial valleys and ridges
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