2,538 research outputs found
On Io, all that flickers is not cold
The 4.8 micron flux from the Galilean satellite Io was shown to fluctuate with an amplitude of approximately 10 percent on time scales of every 28 seconds, 40 minutes, night-to-night, and perhaps year-to-year. Such behavior was found to be the result of random fluctuations for which the mean square fluctuation varies inversely with frequency for constant bandwidth measurement. The theory developed for thermionic emission from barium oxide cathodes in vacuum tubes might be applicable to this situation. If so, the fluctuations in the flux from Io's volcanoes may be caused by diffusion of hot convective cells onto the surface of Io. Long term fluctuations may furnish a means by which the Io volcanism can shut down and conserve energy. Thus the discrepancy that exists between measurements of the current heat flow from Io and calculations of tidal dissipation may be resolved. Tests for rapid flickering at 10 microns showed no fluctuations greater than one percent. This agrees with the prediction of the flow model theory in which the 10 microns volcanic thermal emission arises from cooling of old flows
Determination of the Io heat flow. 1: Eclipse observations
The thermal emission from Io during eclipse by Jupiter yields data from which the total thermal flux from the volcanoes on the satellite surface can be estimated. Thermal infrared observations in spectral bands between 3.5 and 30 microns of five Io eclipse reappearances and one eclipse disappearance are reported and discussed. The thermal emission of the volcanoes which occurs almost all of the time was determined from the Io heat flux data. The thermal observations of Io are discussed with respect to previous thermophysical theories
Microfluidics for Energy Applications
This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.Microfluidic methods developed primarily for medical applications have much to offer energy
applications. This short paper will provide the motivation and outline my group’s recent work in two such
areas: (1) microfluidics and optics for bioenergy and (2) microfluidics for carbon management. Full details
will be provided in talk. Within the bioenergy theme, we are developing photobioreactor architectures that
leverage micro-optics and microfluidics to cater both light and fluids to maximize productivity of
microalgae. Within the carbon management theme we are developing a suite of methods to study porescale
transport and reactivity in carbon sequestration and enhanced oil recovery. Results indicate potential
for order of magnitude gains in photobioreactor technology and a 100-fold improvement over current
subsurface fluid transport analysis methods
Forecasting Electric Vehicle Adoption at a Local Level
The Biden administration has recently stated as a major policy goal that 50% of all new vehicle sales will be electric by the year 2030. However, current electric vehicle (EV) uptake sits at about 2.4% of current vehicle sales. Additionally, the administration’s goal is more ambitious than current forecasts predict will occur. Given the gap between the administration’s goals and the current EV trends, it is necessary to better forecast how current trends will progress and better understand what factors influence these trends. The purpose of this research is two-fold: to create better forecasts of EV adoption at the zip code level and understand how strongly various factors influence adoption rates. To do so, we estimate EV adoption in California at the zip code level via a logistic diffusion model. We examine how adoption varies for battery electric vehicles (BEVs) versus plug-in hybrid EVs (PHEVs). Furthermore, we describe our current work to estimate how various factors – including sociodemographics, the built environment, and charging infrastructure – relate to the adoption parameters suggested by the forecast models. This research can provide valuable insights into adoption trends at a more local level and what factors may be best leveraged to promote adoption
Effects of irrigated and dryland cultivation on soil carbon, nitrogen and phosphorus in northeastern Colorado
2001 Spring.Includes bibliographical references.I investigated the effects of irrigated and fertilized com agriculture on soil C, N and P in northeastern Colorado as they compare to dryland wheat-fallow fields and native rangelands in the semiarid shortgrass steppe of northeastern Colorado. Three replicates each of native rangeland, dry land wheat-fallow, and irrigated corn fields located in or adjacent to the Pawnee National Grasslands were selected for this study. I measured potentially mineralizable C and N from 0-15cm in the soil profile, particulate organic matter (POM) C and Nin the upper 30cm, total and NaHC03-P to a depth of 105cm, and total soil C and N to a depth of 195cm in the soil profile. Irrigated corn fields contained significantly lower mineralizable, POM, and total C and N than rangelands in the upper 5cm of soil. Com fields also had significantly greater NaHCOrP content than rangelands or wheat-fallow fields to a 1-meter depth in the soil. Wheat-fallow fields had significantly less potentially mineralizable and POM C and N than rangelands or corn fields in the upper 5cm of soil. Cumulative losses of total C and N in wheat-fallow fields extended to depths of 75cm or more. There were no significant differences in total P among land use types. Differences in C and N between corn and wheat-fallow fields are likely due to differences in the quantity of plant residue inputs. The distribution of C, N and NaHC03-P through the soil profile in corn fields also differed from rangelands. Soil C, N and NaHC03-P in the soil profile of rangelands decreased from the surf ace down, whereas in com fields C, N and NaHC03-P increased from the surf ace to 30cm and then decreased. Distribution of C, N and P in corn fields may be due to leaching of C or N or decomposition changes in the soil profile. In wheat-fallow fields, C, N and NaHC03-P showed a more uniform distribution in the upper 30cm of soil than rangelands, likely due to tillage practices that mix the upper soil layers in wheat-fallow fields. These results indicate that irrigated and fertilized corn crops in this region of the semiarid shortgrass steppe depletes pools of C and N at the soil surf ace but does not cause a change in C or N below the 5cm layer of soil. The differences in amount and distribution of C and N observed in this study among dryland wheat-fallow and irrigated corn fields indicate that the type of crop grown in this region should be an important consideration for regional studies that evaluate C and N changes due to cultivation
Fourier Transform Multiple Quantum Nuclear Magnetic Resonance
The excitation and detection of multiple quantum transitions in systems of coupled spins offers, among other advantages, an increase in resolution over single quantum n.m.r. since the number of lines decreases as the order of the transition increases. This paper reviews the motivation for detecting multiple quantum transitions by a Fourier transform experiment and describes an experimental approach to high resolution multiple quantum spectra in dipolar systems along with results on some protonated liquid crystal systems. A simple operator formalism for the essential features of the time development is presented and some applications in progress are discussed
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