Warm and Dry Spells (WDS) in Austral Winter over Central South America

The horizontal and vertical structure of unusually warm and dry spells (WDS) over the central parts of South America during the winter and post-winter months (JJAS) are studied. During WDS the mean temperature and humidity anomalies over central Brazil are about +4.1°C and −13.2%, respectively. The mean duration of WDS is 11 days and their mean frequency is less than one per year during the months of JJAS. Apparently, WDS have no preference for the phase of ENSO. Widespread and persistent subsidence in the middle troposphere is observed in tropical Brazil during WDS, which renders the lower tropospheric air warm and dry. The negative anomalies of the specific humidity are observed to be associated with the subsidence regions. A strong, slow moving ridge in the eastern South Pacific and a low-pressure center in northern Argentina are important surface characteristics during the WDS. A more detailed investigation of two specific WDS events, a strong event (August–September 1999) and a moderate one (June 2002), shows a blocking-like situation in the 500-hPa geopotential and surface pressure fields in the Pacific. The South Atlantic subtropical high somewhat approaches the continent. Strong northerlies over the central and eastern parts of Brazil are also observed in the lower troposphere. During WDS the regional circulation acquires summertime characteristics, except for the absence of precipitation, and the circulation in the meridional plane is in the opposite sense from the Hadley circulation. A frontal system, supported by a 500-hPa trough, advances into central Brazil, causing the dissipation of the anomalous situation

Influence of dissipative entry temperature on laminar heat transfer in thermally developing region of a circular pipe with viscous dissipation

Paper presented at the 8th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Mauritius, 11-13 July, 2011.Steady laminar forced convection heat transfer in the thermal entrance region of a circular pipe including viscous dissipation has been studied assuming the flow to be hydrodynamically fully developed and thermally developing. The circular pipe is subjected to constant wall temperature. Two entry temperatures have been considered. 1) A temperature that varies with the radial coordinate obtained in an adiabatic pipe due to viscous dissipation while the flow is hydrodynamically developing. This temperature is termed as the dissipative entry temperature. 2) A uniform temperature equal to the bulk mean value of the dissipative entry temperature. It has been shown that the difference in the Nusselt numbers and heat transfer obtained with these two entry temperatures is insignificant. Thus, the simplicity of classical assumption of uniform entry temperature can be retained when the entry temperature has been chosen as the bulk mean of the dissipative entry temperature.mp201

Crystallization of a scRIP-gelonin isolated from plant seeds Gelonium multiforum

Single crystals of the protein gelonin isolated from the seeds of Gelonium multiforum have been grown at room temperature by vapor diffusion method. The crystals are monclinic with a = 49.4 Å, b = 44.9 Å, c = 137.4 Å, and β = 98.3°. The space group is P21, with two molecules in the asymmetric unit which are related by a noncrystallographic 2-fold axis along ψ =13° and φ =88°. The crystals diffract X-rays to high resolution, making it possible to obtain an accurate structure of this single chain ribosome inactivating protein

Precipitation and water vapor transport in the Southern Hemisphere with emphasis on the South American region

December-March climatologies of precipitation and vertically integrated water vapor transport were analyzed and compared to find the main paths by which moisture is fed to high-rainfall regions in the Southern Hemisphere in this season. The southern tropics (20°S-0°) exhibit high rainfall and receive ample moisture from the northern trades, except in the eastern Pacific and the Atlantic Oceans. This interhemispheric flow is particularly important for Amazonian rainfall, establishing the North Atlantic as the main source of moisture for the forest during its main rainy season. In the subtropics the rainfall distribution is very heterogeneous. The meridional average of precipitation between 358 and 258S is well modulated by the meridional water vapor transport through the 258S latitude circle, being greater where this transport is from the north and smaller where it is from the south. In South America, to the east of the Andes, the moisture that fuels precipitation between 20° and 30°S comes from both the tropical South and North Atlantic Oceans whereas between 30° and 40°S it comes mostly from the North Atlantic after passing over the Amazonian rain forest. The meridional transport (across 25°S) curve exhibits a double peak over South America and the adjacent Atlantic, which is closely reproduced in the mean rainfall curve. This corresponds to two local maxima in the two-dimensional field of meridional transport: the moisture corridor from Amazonia into the continental subtropics and the moisture flow coming from the southern tropical Atlantic into the subtropical portion of the South Atlantic convergence zone. These two narrow pathways of intense moisture flow could be suitably called "aerial rivers." Their longitudinal positions are well defined. The yearly deviations from climatology for moisture flow and rainfall correlate well (0.75) for the continental peak but not for the oceanic peak (0.23). The structure of two maxima is produced by the effect of transients in the time scale of days. © 2009 American Meteorological Society

Inter-hemispheric and inter-zonal moisture transports and monsoon regimes

The principal objectives here are to quantify the strengths of global monsoon circulations in terms of cross-equatorial moisture transport and to verify its behaviour during two extreme years of precipitation over the Amazon Basin. The National Centers for Environmental Prediction / National Center for Atmospheric Research (NCEP/NCAR) Reanalysis data sets for the period 1950–2012 are used in this study and the results are compared with calculations from ERA-Interim data. During the South Asian summer monsoon (JJA), the transport is 82.1 × 107 kg s−1 between 30° and 90°E from the Southern Hemisphere (SH) to the Northern Hemisphere (NH) and reverses to 41.4 × 107 kg s−1 from NH to SH in northern winter (DJF). Over South America between 30° and 90°W, the values are 31.4 × 107 kg s−1 in DJF from NH to SH and 21.5 × 107 kg s−1 in JJA from SH to NH. Although there is no wind reversal from summer to winter seasons over the South American monsoon region, the moisture transport across the equator reverses. The transports during a weak and a strong monsoon in the Amazon Basin are distinctly different suggesting that the cross-equatorial moisture transport can be used as a Monsoon Intensity Index (MII). For the South American monsoon, the DJF index is 28.5 × 107 kg s−1 in the dry year 2004–2005 and 45.1 × 107 kg s−1 in the wet year 2011–2012 as against the climatological value of 31.4 × 107 kg s−1. There is an indication of an inverse relation between the MIIs over the Amazon Basin and the Australian sectors. The annual mean moisture transport across the equator is from SH to NH and is equivalent to three Amazon River discharges. © 2016 Royal Meteorological Societ

Simulation and Integrated Testing of Process Models of PFBR Operator Training Simulator

AbstractHigh fidelity Full Scope Operator Training Simulators play a key role in imparting plant related knowledge to the operating personnel in an effective way. It provides a platform for training the operators on normal and emergency conditions including all types of scenarios that would arise in any Nuclear Power Plant. The scenario based training helps the plant operator to handle a crisis in an efficient manner with the ultimate goal of safe and efficient operation of the plant.This paper discusses about the general description of PFBR Operator Training Simulator, modeling and simulation of various process models, the complexities involved etc. It also covers the associated process logics, controls, display of alarms and indications, malfunctions and transient incidents related to each process model, integration with other sub systems, individual process model testing, integrated performance testing and verification and validation of models. Simulation of process models are broadly classified into two main categories namely, External Models - that are developed in-house and ported to the simulator environment and Internal Models - that are developed using Simulation Tool. External Models are tested on the desk top for intended functioning and after obtaining satisfactory results, the models are ported to the simulator base wherein the Logical and Virtual Panel Models are built to represent a real system of the plant. Internal Models are built using the Simulation Tools and integrated with the External Models after testing. Combination of External and Internal Model represents the total plant and the performance testing is conducted in an Integrated Mode to qua lify the Process Models for training purpose

Different Parameterizations for Wind Variance Applied to the Convective Boundary Layer Growth Model

A evolução da energia cinética turbulenta (ECT) é analisada durante a fase de transição matinal, usando modelos espectrais analíticos. Distintas parametrizações para a variância do vento são introduzidas nos modelos espectrais.  A evolução da ECT para os modelos espectrais tem boa concordância com resultados da simulação de grandes vortices

Nocturnal Jet Simulation Under Neutral Conditions by Theoretical Model

O jato noturno, ou jato de baixos níveis, ocorre normalmente emnoites de céu claro, i.e., sob condições estáveis. Aqui é analisada a ocorrênciado jato noturno em condições neutras por meio de um modelo teórico