Recovery Tests of an Hybrid Current Limiter Composed of a SFCL in Parallel to an Air-Core Power Reactor

The resistive-type superconducting fault current limiters (RSFCL) prototypes using YBCO-coated conductors have shown current limitation for medium voltage class applications for acting time up to 80 ms. By connecting an air-core reactor in parallel with the RSFCL, thus making an hybrid current limiter, one can extend the acting time for up to 1 s. In this work, we report the performance of a hybrid current limiter subjected to an AC peak fault current of 2 kA during 1 s for which within the first 80 ms the SFCL limits the current concurrently with the air-core reactor, and for the remaining 920 ms, only the air-core reactor limits the current. In order to evaluate the actual conditions for subsequent reconnection of RSFCL to the power grid, the hybrid fault current limiter was tested varying the time interval for recovery from 900 ms and 1.2 s, followed again by the concurrent operation of the hybrid limiter during 1 s (SFCL during 80 ms). From this evaluation test, the recovery time can be measured and compared using the voltage peak generated in superconducting module from the first and second fault test. The recovery time was also determined through the pulsed current method (PCM) on short-length sample test. The results showed that the fault current was limited from 1.9 kA down to 514 A after 1 cycle of 60 Hz frequency, with recovery time lower than 1.2 s for two subsequent fault current tests.

Estimation of lower flammability limits of C-H compounds in air at atmospheric pressure, evaluation of temperature dependence and diluent effect

Estimation of the lower flammability limits of C-H compounds at 25 degrees C and 1 atm; at moderate temperatures and in presence of diluent was the objective of this study. A set of 120 degrees C H compounds was divided into a correlation set and a prediction set of 60 compounds each. The absolute average relative error for the total set was 7.89%; for the correlation set, it was 6.09%; and for the prediction set it was 9.68%. However, it was shown that by considering different sources of experimental data the values were reduced to 6.5% for the prediction set and to 6.29% for the total set. The method showed consistency with Le Chatelier's law for binary mixtures of C H compounds. When tested for a temperature range from 5 degrees C to 100 degrees C , the absolute average relative errors were 2.41% for methane; 4.78% for propane; 0.29% for iso-butane and 3.86% for propylene. When nitrogen was added, the absolute average relative errors were 2.48% for methane; 5.13% for propane; 0.11% for iso-butane and 0.15% for propylene. When carbon dioxide was added, the absolute relative errors were 1.80% for methane; 5.38% for propane; 0.86% for iso-butane and 1.06% for propylene. (C) 2014 Elsevier B.V. All rights reserved.

Analysis of hourly global, direct and diffuse solar radiations attenuation as a function of optical air mass

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

Analysis of oxy-fuel combustion as an alternative to combustion with air in metal reheating furnaces

Using oxygen instead of air in a burning process is at present being widely discussed as an option to reduce CO2 emissions. One of the possibilities is to maintain the combustion reaction at the same energy release level as burning with air, which reduces fuel consumption and the emission rates of CO2. A thermal simulation was made for metal reheating furnaces, which operate at a temperature in the range of 1150-1250 degrees C, using natural gas with a 5% excess of oxygen, maintaining fixed values for pressure and combustion temperature. The theoretical results show that it is possible to reduce the consumption of fuel, and this reduction depends on the amount of heat that can be recovered during the air pre-heating process. The analysis was further conducted by considering the 2012 costs of natural gas and oxygen in Brazil. The use of oxygen showed to be economically viable for large furnaces that operate with conventional heat recovering systems (those that provide pre-heated air at temperatures near 400 degrees C). (C) 2014 Elsevier Ltd. All rights reserved.

Assessment of broiler surface temperature variation when exposed to different air temperatures

This study was conducted to determine the effect of the air temperature variation on the mean surface temperature (MST) of 7-to 35-day-old broiler chickens using infrared thermometry to estimate MST, and to study surface temperature variation of the wings, head, legs, back and comb as affected by air temperature and broiler age. One hundred Cobb(R) broilers were used in the experiment. Starting on day 7, 10 birds were weekly selected at random, housed in an environmental chamber and reared under three distinct temperatures (18, 25 and 32 degrees C) to record their thermal profile using an infrared thermal camera. The recorded images were processed to estimate MST by selecting the whole area of the bird within the picture and comparing it with the values obtained using selected equations in literature, and to record the surface temperatures of the body parts. The MST estimated by infrared images were not statistically different (p > 0.05) from the values obtained by the equations. MST values significantly increased (p < 0.05) when the air temperature increased, but were not affected by bird age. However, age influenced the difference between MST and air temperature, which was highest on day 14. The technique of infrared thermal image analysis was useful to estimate the mean surface temperature of broiler chickens.

Autonomic control of post-air-breathing tachycardia in Clarias gariepinus (Teleostei: Clariidae)

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

Development of technologies and methods for monitoring the spatial variability of air temperature in greenhouse environment

Climatic factors directly influence growth and productivity of plants inside greenhouses, where temperature can be considered one of the major parameter in this context. Thus, the aim of this research was to develop a low cost device for thermal sensing and data acquisition, and use it in data collection and analysis of spatial variability of temperature inside a greenhouse with tropical climate. The developed equipment for thermal measurements showed a high degree of accuracy and fast responses in measurements, proving its efficiency. The data analysis interpretations were made from the elaborations of variograms and of tridimensional maps generated by a geostatistical software. The processed data analysis presented that a greenhouse without thermal control has spatial variations of air temperature, both in the sampled horizontals layers as in the three analyzed vertical columns, presenting variations of up to 3.6 ºC in certain times.

Coffee growth, pest and yield responses to free-air CO2 enrichment

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

RB30-245 Water Supply and Sewage Disposal Systems for Farm Homes

When the well "goes dry" or when the windmill or pump breaks down, every one in the household immediately appreciates the value fo plenty of water. In other words, "You never miss the water until the well runs dry." Fortunately, in most sections of this state, plenty of pure water may be obtained by sinking wells of moderate depth, yet surprisingly few farm homes are supplied with running water in the kitchen even though the barn yards are equipped with hydrants and tanks. It is the purpose of this bulletin to present a number of water supply and sewage disposal systems which have been used in Nebraska and surrounding states and which add greatly to the comfort and convenience of the farm home.

Compressed Air, Wooden Clappers, and Other Non-Traditional Methods for Dispersing European Starlings from an Urban Roost

During autumn 2003, several thousand European starlings (Sturnus vulgaris) began roosting on exposed I-beams in a newly constructed, decorative glass canopy that covered the passenger pick-up area at the terminal building for Cleveland Hopkins International Airport, Ohio. The use of lethal control or conventional dispersal techniques, such as pyrotechnics and fire hoses, were not feasible in the airport terminal area. The design and aesthetics of the structure precluded the use of netting and other exclusion materials. In January 2004, an attempt was made to disperse the birds using recorded predator and distress calls broadcast from speakers installed in the structure. This technique failed to disperse the birds. In February 2004, we developed a technique using compressed air to physically and audibly harass the birds. We used a trailer-mounted commercial air compressor producing 185 cubic feet per minute of air at 100 pounds per square inch pressure and a 20-foot long, 1-inch diameter PVC pipe attached to the outlet hose. One person slowly (< 5 mph) drove a pick-up truck through the airport terminal at dusk while the second person sat on a bench in the truck bed and directed the compressed air from the pipe into the canopy to harass starlings attempting to enter the roost site. After 5 consecutive nights of compressed-air harassment, virtually no starlings attempted to roost in the canopy. Once familiar with the physical effects of the compressed air, the birds dispersed at the sound of the air. Only occasional harassment at dusk was needed through the remainder of the winter to keep the canopy free of starlings. Similar harassment with the compressor was conducted successfully in autumn 2004 with the addition of a modified leaf blower, wooden clappers, and laser. In conclusion, we found compressed air to be a safe, unobtrusive, and effective method for dispersing starlings from an urban roost site. This technique would likely be applicable for other urban-roosting species such as crows, house sparrows, and blackbirds.

A simple and effective air shotgun for collecting small birds and other vertebrates at close range

Scientific collections are important sources of material for many areas of ornithological research. Although firearms (particularly shotguns) have been the standard for avian scientific collecting for more than 100 years, their use is restricted in many areas of the world. We describe a cheap, relatively silent, and effective air shotgun for collecting birds weighing up to 50 g at distances up to 4 m. This air shotgun is capable of shooting birdshot, uses hollow metal rivets connected to plastic straws as shot shells, and represents a simple adaptation of any 0.177 or 0.22 cal single-shot, break-barrel air rifle with at least 25 joules of muzzle energy. This air shotgun will be especially useful for focused sampling of birds (and other small vertebrates) in situations where firearm use or transport is restricted.

Biogeography in the air: fungal diversity over land and oceans

Biogenic aerosols are relevant for the Earth system, climate, and public health on local, regional, and global scales. Up to now, however, little is known about the diversity and biogeography of airborne microorganisms. We present the first DNA-based analysis of airborne fungi on global scales, showing pronounced geographic patterns and boundaries. In particular we find that the ratio of species richness between Basidiomycota and Ascomycota is much higher in continental air than in marine air. This may be an important difference between the 'blue ocean' and 'green ocean' regimes in the formation of clouds and precipitation, for which fungal spores can act as nuclei. Our findings also suggest that air flow patterns and the global atmospheric circulation are important for the understanding of global changes in biodiversity.

Urban Air Pollutants are Significant Risk Factors for Asthma and Pneumonia in Children: The Influence of Location on the Measurement of Pollutants

Background: Air pollution is associated with a substantial burden on human health; however, the most important pollutants may vary with location. Proper monitoring is necessary to determine the effect of these pollutants on respiratory health. Objectives: This study was designed to evaluate the role of outdoor, indoor and personal exposure to combustion-related pollutants NO2 and O-3 on respiratory health of children in a non-affluent urban area of Sao Paulo, Brazil. Methods: Levels of NO2 and O-3 were continuously measured in outdoor and indoor air, as well as personal exposure, for 30 days using passive measurement monitors. Respiratory health was assessed with a Brazilian version of the ISAAC questionnaire. Results: Complete data were available from 64 children, aged 6-10 years. Respiratory morbidity was high, with 43 (67.2%) reporting having had wheezing at any time, 27 (42.2%) wheezing in the last month, 17 (26.6%) asthma at any time and 21(32.8%) pneumonia at any time. Correlations between levels of NO2 and O-3 measured in the three locations evaluated were poor. Levels of NO2 in indoor air and personal exposure to O-3 were independently associated with asthma (both cases P=.02), pneumonia (O-3, P=.02) and wheezing at any time (both cases P<.01). No associations were seen between outdoor NO2 and O-3 and respiratory health. Conclusions: Exposure to higher levels of NO2 and O-3 was associated with increased risk for asthma and pneumonia in children. Nonetheless, the place where the pollutants are measured influences the results. The measurements taken in indoor and personal exposure were the most accurate. (C) 2012 SEPAR. Published by Elsevier Espana, S.L. All rights reserved.

Air accident investigation among regulatory agencies

The aim of this manuscript is to describe and compare regulatory aviation agencies according to their subordination and attributions to investigate air accidents. Possible consequences in identifying the contributory factors are also presented. Distinct procedures investigating air accidents among agencies lead to a lack of standardization of the statistics, making it difficult to analyze the data globally. Separately the information does not configure the entire scenario of what occurred, affecting the analysis and subsequent interventions. We recommend a joint and collaborative work between the different committees that operate in the investigation of air accidents.

Ambient levels of air pollution induce clinical worsening of blepharitis

Background: Even though air pollutants exposure is associated with changes in the ocular surface and tear film, its relationship to the clinical course of blepharitis, a common eyelid disease, had not yet been investigated. Our objective was to investigate the correlation between air pollution and acute manifestations of blepharitis. Method: We recorded all cases of changes in the eyelids and ocular surface, and rated clinical findings on a scale from zero (normal) to two (severe alterations). Daily values of carbon monoxide, particulate matter smaller than 10 mu m in diameter and nitrogen dioxide concentrations and meteorological variables (temperature and relative humidity) in the vicinity of the medical service were obtained. Specific linear regression models for each outcome were constructed including pollutants as independent variables (single pollutant models). Temperature and humidity were included as confounding variables. Results: increases of 28.8 mu g/m(3) in the concentration of particulate matter and 1.1 ppm in the concentration of CO were associated with increases in cases of blepharitis on the day of exposure (5 cases, 95% CI: 1-10 and 6 cases, 95% CI: 1-12, respectively). Conclusion: Exposure to usual air pollutants concentrations present in large cities affects, in a consistent manner, the eyes of residents contributing to the increasing incidence of diseases of the eyelid margin. (C) 2011 Elsevier Inc. All rights reserved.