Экстравазальная коррекция клапанов глубоких вен у пациентов с рецидивом варикозной болезни нижних конечностей

варикозное расширение вен /хирвеныконечность нижняя /хи

Scenario Grouping and Classification Methodology for Postprocessing of Data Generated by Integrated Deterministic-Probabilistic Safety Analysis

Integrated Deterministic-Probabilistic Safety Assessment (IDPSA) combines deterministic model of a nuclear power plant with a method for exploration of the uncertainty space. Huge amount of data is generated in the process of such exploration. It is very difficult to “manually” process and extract from such data information that can be used by a decision maker for risk-informed characterization, understanding, and eventually decision making on improvement of the system safety and performance. Such understanding requires an approach for interpretation, grouping of similar scenario evolutions, and classification of the principal characteristics of the events that contribute to the risk. In this work, we develop an approach for classification and characterization of failure domains. The method is based on scenario grouping, clustering, and application of decision trees for characterization of the influence of timing and order of events. We demonstrate how the proposed approach is used to classify scenarios that are amenable to treatment with Boolean logic in classical Probabilistic Safety Assessment (PSA) from those where timing and order of events determine process evolution and eventually violation of safety criteria. The efficiency of the approach has been verified with application to the SARNET benchmark exercise on the effectiveness of hydrogen management in the containment

Approach and Development of Effective Models for Simulation of Thermal Stratification and Mixing Induced by Steam Injection into a Large Pool of Water

Steam venting and condensation in a large pool of water can lead to either thermal stratification or thermal mixing. In a pressure suppression pool (PSP) of a boiling water reactor (BWR), consistent thermal mixing maximizes the capacity of the pool while the development of thermal stratification can reduce the steam condensation capacity of the pool which in turn can lead to pressure increase in the containment and thereafter the consequences can be severe. Advanced modeling and simulation of direct contact condensation in large systems remain a challenge as evident in commercial and research codes mainly due to small time-steps necessary to resolve contact condensation in long transients. In this work, effective models, namely, the effective heat source (EHS) and effective momentum source (EMS) models, are proposed to model and simulate thermal stratification and mixing during a steam injection into a large pool of water. Specifically, the EHS/EMS models are developed for steam injection through a single vertical pipe submerged in a pool under two condensation regimes: complete condensation inside the pipe and chugging. These models are computationally efficient since small scale behaviors are not resolved but their integral effect on the large scale flow structure in the pool is taken into account

Validation of Effective Models for Simulation of Thermal Stratification and Mixing Induced by Steam Injection into a Large Pool of Water

The Effective Heat Source (EHS) and Effective Momentum Source (EMS) models have been proposed to predict the development of thermal stratification and mixing during a steam injection into a large pool of water. These effective models are implemented in GOTHIC software and validated against the POOLEX STB-20 and STB-21 tests and the PPOOLEX MIX-01 test. First, the EHS model is validated against STB-20 test which shows the development of thermal stratification. Different numerical schemes and grid resolutions have been tested. A 48×114 grid with second order scheme is sufficient to capture the vertical temperature distribution in the pool. Next, the EHS and EMS models are validated against STB-21 test. Effective momentum is estimated based on the water level oscillations in the blowdown pipe. An effective momentum selected within the experimental measurement uncertainty can reproduce the mixing details. Finally, the EHS-EMS models are validated against MIX-01 test which has improved space and time resolution of temperature measurements inside the blowdown pipe. Excellent agreement in averaged pool temperature and water level in the pool between the experiment and simulation has been achieved. The development of thermal stratification in the pool is also well captured in the simulation as well as the thermal behavior of the pool during the mixing phase

Design, Performance, and Calibration of CMS Hadron Endcap Calorimeters

Detailed measurements have been made with the CMS hadron calorimeter endcaps (HE) in response to beams of muons, electrons, and pions. Readout of HE with custom electronics and hybrid photodiodes (HPDs) shows no change of performance compared to readout with commercial electronics and photomultipliers. When combined with lead-tungstenate crystals, an energy resolution of 8\% is achieved with 300 GeV/c pions. A laser calibration system is used to set the timing and monitor operation of the complete electronics chain. Data taken with radioactive sources in comparison with test beam pions provides an absolute initial calibration of HE to approximately 4\% to 5\%

Analysis of the Effect of Severe Accident Scenario on Debris Properties in Lower Plenum of Nordic BWR Using Different Versions of MELCOR Code

Nordic Boiling Water Reactors (BWRs) employ ex-vessel debris coolability as a severe accident management strategy (SAM). Core melt is released into a deep pool of water where formation of noncoolable debris bed and ex-vessel steam explosion can pose credible threats to containment integrity. Success of the strategy depends on the scenario of melt release from the vessel that determines the melt-coolant interaction phenomena. The melt release conditions are determined by the in-vessel phase of severe accident progression. Specifically, properties of debris relocated into the lower plenum have influence on the vessel failure and melt release mode. In this work we use MELCOR code for prediction of the relocated debris. Over the years, many code modifications have been made to improve prediction of severe accident progression in light-water reactors. The main objective of this work is to evaluate the effect of models and best practices in different versions of MELCOR code on the in-vessel phase of different accident progression scenarios in Nordic BWR. The results of the analysis show that the MELCOR code versions 1.86 and 2.1 generate qualitatively similar results. Significant discrepancy in the timing of the core support failure and relocated debris mass in the MELCOR 2.2 compared to the MELCOR 1.86 and 2.1 has been found for a domain of scenarios with delayed time of depressurization. The discrepancies in the results can be explained by the changes in the modeling of degradation of the core components and changes in the Lipinski dryout model in MELCOR 2.2

Determination of diapir distribution in the adjacent territory of Ulmale bluff by using GPR

Bakalaura darba mērķis ir noskaidrot diapīru izplatību Ulmales stāvkrasta pieguļošajā teritorijā, izmantojot radiolokācijas metodi. Iepriekšējie pētījumi balstās tikai uz stāvkrastā esošajiem atsegumiem, tādēļ nav informācijas par to, cik tālu diapīrisma procesi ir bijuši izplatīti. Lauka darbi ietver pētījumu par Ulmales stāvkrasta atsegumā sastopamajām diapīru struktūrām. Savukārt, izmantojot radiolokācijas metodi, stāvkrasta pieguļošajā teritorijā tika ierīkoti 30 profili. Rezultātā tika iegūta karte, kas parāda ar ģeoradaru iegūto signāla atstarojumu dziļumus, kas savukārt atspoguļo diapīru virsmu. Pētījumā iegūtie rezultāti liecina, ka ar radiolokācijas pētījumu metodi ir iespējams noteikt diapīru izplatību, kā arī iepriekš pieņemtais uzskats, ka morēnas veidošanās ir saistīta ar diapīrisma procesiem, nav attiecināms uz šo teritoriju.The aim of the bachelor thesis is to find out the distribution of diapirs in the adjacent territory of Ulmale bluff by using GPR. Previous studies focuses only on the outcrops of the bluff, so there is limited information on how far the processes of diapirism were distributed. Fieldwork includes a study of the diapir structures found on outcrop of the Ulmale bluff. Using the radiolocation method, 30 profiles were installed in the adjacent area of the bluff. As the result we have a map showing the depth of reflection of the signal obtained by the georadar, which in turn represents the surface of the diapirs. The results of the study shows that it is possible to determine the distribution of the diapirs with by using GPR in the adjacent territory of Ulmale bluff. Also the previously believed that the formation of till sediments is related to the processes of diapirism, is not applicable to this territory

Development of Scaling Approach for Prediction of Terminal Spread Thickness of Melt Poured into a Pool of Water

Corium melt stabilization and long term cooling in a pool of water located beneath reactor vessel is adopted in several existing designs of light water reactors (LWRs) as an element in severe accident (SA) mitigation strategy. At certain conditions of melt release into the pool (e.g. large ratio of the vessel breach size to the pool depth), liquid melt can spread under water and reach a coolable configuration. Coolability of the melt is contingent on terminal spread thickness of the melt layer \delta_{sp} which defines decay heat generated per unit area of the melt surface. The thickness of the melt layer is determined by the competition between characteristic time scales of hydrodynamic melt spreading and solidification of the melt. This paper presents a modification of the scaling approach, originally proposed by Dinh et al. (2000) for prediction of the terminal melt spread thickness, to the case when liquid melt jet is poured into a pool of water and allow to spread unrestricted on a horizontal floor of the pool. Modified scaling approach takes into account mass and heat losses during to melt jet interaction with the coolant. The hydrodynamic spreading timescale is described with phenomenological approaches proposed by Huppert and Britter (1982) and Britter (1979). Proposed model is validated against PULiMS experiments (Pouring and Underwater Liquid Melt Spreading Konovalenko et al., 2012). Finally, sensitivity analysis and preliminary assessments of the uncertainties are performed for the PULiMS test conditions.BEST PAPER AWARD!QC 20131216</p