Overvoltage protection network

Electrical equipment to be protected from overvoltage is connected with a possible source of overvoltage via an input conductor. A fuse is connected in series with the input conductor. A spark gap is connected between the input conductor and ground for conducting the overvoltage current to ground and for blowing the fuse to open the circuit to the electrical equipment. A pulse attenuator network is provided between the spark gap and the electrical equipment to be protected for attenuating the pulse of energy passing through the fuse and spark gap prior to blowing of the fuse. The pulse attenuator network includes additional shunt spark gaps, series inductance, and a series connection of a twisted shielded pair of conductors having low-voltage insulation

High voltage protection network

Circuit protects technical personnel and test equipment from hazardous currents conducted through safety barriers and into data acquisition equipment. Network isolates energy source, restricts arcing to remote area, and dissipates harmlessly residual energy transient

The revolution in data gathering systems

Data acquisition systems used in NASA's wind tunnels from the 1950's through the present time are summarized as a baseline for assessing the impact of minicomputers and microcomputers on data acquisition and data processing. Emphasis is placed on the cyclic evolution in computer technology which transformed the central computer system, and finally the distributed computer system. Other developments discussed include: medium scale integration, large scale integration, combining the functions of data acquisition and control, and micro and minicomputers

Real-time computer data system for the 40- by 80-foot wind tunnel facility at Ames Research Center

The background material and operational concepts of a computer-based system for an operating wind tunnel are described. An on-line real-time computer system was installed in a wind tunnel facility to gather static and dynamic data. The computer system monitored aerodynamic forces and moments of periodic and quasi-periodic functions, and displayed and plotted computed results in real time. The total system is comprised of several off-the-shelf, interconnected subsystems that are linked to a large data processing center. The system includes a central processor unit with 32,000 24-bit words of core memory, a number of standard peripherals, and several special processors; namely, a dynamic analysis subsystem, a 256-channel PCM-data subsystem and ground station, a 60-channel high-speed data acquisition subsystem, a communication link, and static force and pressure subsystems. The role of the test engineer as a vital link in the system is also described

Source identification and quantification of particulate matter emitted from livestock houses

There is need to identify and quantify the contribution of different sources to airborne particulate matter (PM) emissions from animal houses. To this end, we compared the chemical and morphological characteristics of fine and coarse PM from known sources collected from animal houses with the characteristics of on-farm fine and coarse airborne PM using two methods: classification rules based on decision trees and multiple linear regression. Fourteen different farms corresponding to seven different housing systems for poultry and pigs were sampled during winter. A total of 28 fine and 28 coarse on-farm airborne PM samples were collected, together with a representative sample of each known source per farm (56 known source samples in total). Source contributions were calculated as relative percentage contributions in particle numbers and then estimated in particle mass. Based on particle numbers, results showed that in poultry houses, most on-farm airborne PM originated from feathers (ranging from 4% to 43% in fine PM and from 6% to 35% in coarse PM) and manure (ranging from 9% to 85% in fine PM and from 30% to 94% in coarse PM). For pigs, most on-farm airborne PM originated from manure (ranging from 70% to 98% in fine PM and from 41% to 94% in coarse PM). Based on particle mass, for poultry most on-farm airborne PM still originated from feathers and manure; for pigs, however, most PM originated from skin and manure. Feed had a negligible contribution to on-farm airborne PM compared with other sources. Results presented in this study improve the understanding of sources of PM in different animal housing systems, which may be valuable when choosing optimal PM reduction technique

Measures to reduce fine dust emission from poultry houses: reduction from broiler houses by ionization

In this study the effect was determined of a commercially available air ionization system on the reduction of airborne dust in a broiler house. Results showed a reduction, based on particle mass, of 36% and 10% for PM10 and PM2.5, respectivel

Options for dust reduction from poultry houses

Large poultry houses emit high amounts of fine dust (PM10) and in many cases they exceed the ambient air quality standard set by the EU. Technologies for PM10 reduction need to be developed on short term to minimize PM10 emissions from poultry houses. Studied options for dust reduction were: application of an oil film on the litter and application of an ionization system. Rapeseed oil was sprayed daily in a quantity of 8 to 24 ml/m2 in broiler houses and 20 ml/m2 in layer houses. The ionization system was applied in a broiler house and had a voltage difference of -30kV, with a current of approximately 0.7 mA. Daily emissions of PM10 particles were determined at regular intervals by measuring concentrations at the ventilation inlet and outlet and by measuring the airflow rate. For the oil system PM10 emission reductions were in the ranges of 55 – 85% in broilers and 25 – 40% in layers. The ionization system, applied in broilers, reduced PM10 emission on average by 36%

Moluscos del yacimiento paleontológico de "Lo Hueco" (Cretácico Superior, Cuenca, España): Implicaciones paleoambientales y secuenciales

In the exceptional site of "Lo Hueco" (Cuenca, Spain) more than 8500 macroremains of plants, invertebrates and vertebrates, including titanosaur sauropod dinosaurs, have been collected in a succession of Upper Cretaceous "Garumn" facies. This work describes the molluscs found together, interpreting their palaeoenvironmental and sequential meaning. The sample is comparatively scarce due to the urgency of the excavation, and to constraints of the preservational scenario, seemingly not ideal for the fossilization of carbonated remains. Thus, the absence of well preserved shells has motivated the use of open nomenclature. Bivalves are recorded by unarticulated marly mudstone moulds of Margaritifera sp., Anodonta sp., ?Corbicula sp. and Pisidium sp., and most gastropods by gypsum moulds of Faunus sp. This association indicates a typical freshwater palaeofauna, where the presence of Melanopsidae gastropods can suggest the sporadic influence of moderately brackish-water episodes. These data confirm previous palaeoenvironmental interpretations proposed for the site. Additionally, the presence of the terrestrial gastropod Palaeocyclophorus sp. in underlying beds with high proportion of vegetal terrestrial organic matter, and situated over an important erosive discordance, has allowed to locate the beginning of the depositional sequence of "Lo Hueco".En el excepcional yacimiento paleontológico de "Lo Hueco" (Cuenca, España) se han obtenido más de 8500 macrorrestos de plantas, invertebrados y vertebrados, incluyendo dinosaurios saurópodos titanosaurios, en una sección del Cretácico Superior en facies "Garumn". El presente trabajo describe los moluscos recogidos, interpretando su significado paleoambiental y secuencial. La muestra obtenida resulta relativamente reducida debido a la urgencia de la excavación, y a que las condiciones diagenéticas posiblemente no han favorecido la preservación de restos carbonatados. En consecuencia, la ausencia de conchas bien preservadas ha obligado a la utilización de nomenclatura abierta. Los bivalvos identificados se encuentran representados por moldes margosos desarticulados de Margaritifera sp., Anodonta sp., ?Corbicula sp. y Pisidium sp., y la mayoría de los gasterópodos por moldes de yeso de Faunus sp. Esta asociación corresponde a una típica paleofauna de agua dulce, en la que la presencia de gasterópodos melanópsidos parece sugerir la influencia esporádica de episodios de agua salobre. Estos datos confirman las interpretaciones paleoambientales previas propuestas para el yacimiento. Adicionalmente, la presencia del gasterópodo terrestre Palaeocyclophorus sp. en niveles infrayacentes con una elevada proporción de materia orgánica vegetal, situados sobre una importante discordancia erosiva, ha permitido localizar el inicio de la secuencia deposicional correspondiente a "Lo Hueco"

References

www.biogeosciences-discuss.net/11/8373/2014/ doi:10.5194/bgd-11-8373-2014 © Author(s) 2014. CC Attribution 3.0 License. This discussion paper is/has been under review for the journal Biogeosciences (BG). Please refer to the corresponding final paper in BG if available. Wind-induced upwelling in the Kerguele