A case study of convective organization into precipitating lines in the Southwest Amazon during the WETAMC and TRMM-LBA

A case study of convective development in the Southwest Amazon region during the Wet Season Atmospheric Mesoscale Campaign (WETAMC) and Tropical Rainfall Measuring Mission (TRMM)/Large-Scale Biosphere-Atmosphere (LBA) Experiment in Amazonia is presented. The convective development during 7 February 1999 is shown to occur during a period of very weak large-scale forcing in the presence of topography and deforestation. The available data include dual Doppler radar analysis, radiosonde launches, and surface and boundary layer observations. The observational analysis is complemented with a series of model simulations using the RAMS with 2-km resolution over a 300 km 300 km area forced by a morning radiosonde profile. A comparison of the observed and simulated thermodynamic transformation of the boundary layer and of the formation of convective lines, and of their kinematic and microphysical properties is presented. It is shown that only a few very deep and intense convective cells are necessary to explain the overall precipitating line formation and that discrete propagation and coupling with upper atmosphere circulations may explain the appearance of several lines. The numerical simulation indicates that topography may be the cause of initial convective development, although later on the convective line is parallel to the midlevel shear. There are indications that small-scale deforestation may have an effect on increasing rainfall in the wet season when the large-scale forcing is very weak.

Convective storm initiation in a moist tropical environment

Radar and satellite data from the Tropical Rainfall Measuring Mission-Large-Scale Biosphere-Atmosphere (TRMM-LBA) project have been examined to determine causes for convective storm initiation in the southwest Amazon region. The locations and times of storm initiation were based on the National Center for Atmospheric Research (NCAR) S-band dual-polarization Doppler radar (S-Pol). Both the radar and the Geostationary Operational Environmental Satellite-8 (GOES-8) visible data were used to identify cold pools produced by convective precipitation. These data along with high-resolution topographic data were used to determine possible convective storm triggering mechanisms. The terrain elevation varied from 100 to 600 m. Tropical forests cover the area with numerous clear-cut areas used for cattle grazing and farming. This paper presents the results from 5 February 1999. A total of 315 storms were initiated within 130 km of the S-Pol radar. This day was classified as a weak monsoon regime where convection developed in response to the diurnal cycle of solar heating. Scattered shallow cumulus during the morning developed into deep convection by early afternoon. Storm initiation began about 1100 LST and peaked around 1500-1600 LST. The causes of storm initiation were classified into four categories. The most common initiation mechanism was caused by forced lifting by a gust front (GF; 36%). Forcing by terrain (>300 m) without any other triggering mechanism accounted for 21% of the initiations and colliding GFs accounted for 16%. For the remaining 27% a triggering mechanism was not identified. Examination of all days during TRMM-LBA showed that this one detailed study day was representative of many days. A conceptual model of storm initiation and evolution is presented. The results of this study should have implications for other locations when synoptic-scale forcing mechanisms are at a minimum. These results should also have implications for very short-period forecasting techniques in any location where terrain, GFs, and colliding boundaries influence storm evolution.

Transient non-Darcy forced convective heat transfer from a flat plate embedded in a fluid-saturated porous medium

Transient non-Darcy forced convection on a flat plate embedded in a porous medium is investigated using the Forchheimer-extended Darcy law. A sudden uniform pressure gradient is applied along the flat plate, and at the same time, its wall temperature is suddenly raised to a high temperature. Both the momentum and energy equations are solved by retaining the unsteady terms. An exact velocity solution is obtained and substituted into the energy equation, which then is solved by means of a quasi-similarity transformation. The temperature field can be divided into the one-dimensional transient (downstream) region and the quasi-steady-state (upstream) region. Thus the transient local heat transfer coefficient can be described by connecting the quasi-steady-state solution and the one-dimensional transient solution. The non-Darcy porous inertia works to decrease the velocity level and the time required for reaching the steady-state velocity level. The porous-medium inertia delays covering of the plate by the steady-state thermal boundary layer. © 1990.

Statistics on tropical convective storms observed by radar

Convective storm rainfall is of special importance to urban hydrological studies due to its temporal and spatial variability. Although dense networks of recording rain gauges can be employed to characterize such rainfall, very few investigations of this type have been undertaken due to their prohibitive cost. This paper reports some data on characteristics of tropical convective storms obtained from radar at Bauru in the State of São Paulo, Brazil. Periods of convective precipitation were identified by exclusion of those related to frontal activity with the help of synoptic maps and the radar screen record. The occurrence and evolution of convective storms were observed in two 28 km × 28 km windows obtaining information on the life history of convective cells and the magnitude of rainfall. Frequency distributions of the time of occurrence of convective rainfall, cell size, area covered, life duration and maximum and average rainfall observed in the experimental areas are presented and discussed.

Elevation of boiling point of coffee extract

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Thermal evaporation: Representation of rise in boiling point of grapefruit juice

The rise in boiling point of grapefruit juice was experimentally measured at soluble solids concentrations in the range of 9.3-60.6 °Brix and pressures between °6.0 × 103 and 9.0 × 104 Pa. Different approaches to represent experimental data, including the Dhring's rule, the Antoine equation and empirical models proposed in the literature were tested. In the range of 9.3-29.0 °Brix, the rise in boiling point was nearly independent of pressure, varying only with juice concentration. Considerable deviations of this behavior began to occur at concentrations higher than 29.0 °Brix. Experimental data could be best predicted by adjusting an empirical model, which consisted of a single equation that takes into account the dependence of rise in boiling point on pressure and concentration. © SAGE Publications 2007.

Implementation of convective heating in Companhia Siderúrgica Nacional Blast Furnace runners

This paper describes the main characteristics and advantages of convective heating system for refractory lining, compared with conventional heating systems. In addition the main results obtained are presented with its implementation in CSN Blast Furnace #2 and 3 Runners, in terms of cost and equipment availability, as well as the need for ceramic coating to protect the lining against oxidation, arising from excessive air combustion. © 2012 Elsevier Ltd. All rights reserved.

Influence of nanoparticle size and gap size on nucleate boiling using HFE7100

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effects of edible coatings on convective drying and characteristics of the dried pineapple

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influence of summertime mesoscale convective systems on the heat balance and surface mixed layer dynamics of a large Amazonian hydroelectric reservoir

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A simple boiling-based DNA extraction for RAPD profiling of landfarm soil to provide representative metagenomic content

Landfarm soils are employed in industrial and petrochemical residue bioremediation. This process induces selective pressure directed towards microorganisms capable of degrading toxic compounds. Detailed description of taxa in these environments is difficult due to a lack of knowledge of culture conditions required for unknown microorganisms. A metagenomic approach permits identification of organisms without the need for culture. However, a DNA extraction step is first required, which can bias taxonomic representativeness and interfere with cloning steps by extracting interference substances. We developed a simplified DNA extraction procedure coupled with metagenomic DNA amplification in an effort to overcome these limitations. The amplified sequences were used to generate a metagenomic data set and the taxonomic and functional representativeness were evaluated in comparison with a data set built with DNA extracted by conventional methods. The simplified and optimized method of RAPD to access metagenomic information provides better representativeness of the taxonomical and metabolic aspects of the environmental samples.

A Simple Method to Evaluate, Correlate and Predict Boiling and Flash Points of Alkynes

Boiling points (T-B) of acyclic alkynes are predicted from their boiling point numbers (Y-BP) with the relationship T-B(K) = -16.802Y(BP)(2/3) + 337.377Y(BP)(1/3) - 437.883. In turn, Y-BP values are calculated from structure using the equation Y-BP = 1.726 + A(i) + 2.779C + 1.716M(3) + 1.564M + 4.204E(3) + 3.905E + 5.007P - 0.329D + 0.241G + 0.479V + 0.967T + 0.574S. Here A(i) depends on the substitution pattern of the alkyne and the remainder of the equation is the same as that reported earlier for alkanes. For a data set consisting of 76 acyclic alkynes, the correlation of predicted and literature T-B values had an average absolute deviation of 1.46 K, and the R-2 of the correlation was 0.999. In addition, the calculated Y-BP values can be used to predict the flash points of alkynes.

Flow Boiling Characteristics for R1234ze(E) in 1.0 and 2.2 mm Circular Channels

Experimental flow boiling heat transfer results are presented for horizontal 1.0 and 2.2 mm I. D. (internal diameter) stainless steel tubes for tests with R1234ze(E), a new refrigerant developed as a substitute for R134a with a much lower global warming potential (GWP). The experiments were performed for these two tube diameters in order to investigate a possible transition between macro and microscale flow boiling behavior. The experimental campaign includes mass velocities ranging from 50 to 1500 kg/m(2) s, heat fluxes from 10 to 300 kW/m(2), exit saturation temperatures of 25, 31 and 35 degrees C, vapor qualities from 0.05 to 0.99 and heated lengths of 180 mm and 361 mm. Flow pattern characterization was performed using high speed videos. Heat transfer coefficient, critical heat flux and flow pattern data were obtained. R1234ze(E) demonstrated similar thermal performance to R134a data when running at similar conditions. [DOI: 10.1115/1.4004933]

A simple method to evaluate, correlate and predict boiling and flash points of alkynes

Boiling points (T B) of acyclic alkynes are predicted from their boiling point numbers (Y BP) with the relationship T B(K) = -16.802Y BP2/3 + 337.377Y BP1/3 - 437.883. In turn, Y BP values are calculated from structure using the equation Y BP = 1.726 + Ai + 2.779C + 1.716M3 + 1.564M + 4.204E3 + 3.905E + 5.007P - 0.329D + 0.241G + 0.479V + 0.967T + 0.574S. Here Ai depends on the substitution pattern of the alkyne and the remainder of the equation is the same as that reported earlier for alkanes. For a data set consisting of 76 acyclic alkynes, the correlation of predicted and literature T B values had an average absolute deviation of 1.46 K, and the R² of the correlation was 0.999. In addition, the calculated Y BP values can be used to predict the flash points of alkynes.