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1.
Andreas Herschel 《Limnologica》1999,29(2):195
A series of 7 growth experiments with Metallogenium sp. was conducted in a flow-through reactor (chemostat). The results demonstrate that Metallogenium sp. grows under simulated lake water conditions in the laboratory. Metallogenium reacted in the chemostat in the same way as a microorganism. The growth rates of the microorganism Metallogenium were determined. It can be concluded therefore that the maximal growth rate at a temperature of 15 °C was 0.7 d−1. 相似文献
2.
It has been shown that the solar line 5250.2 (Fei) is weakly blended with a telluric line in the water vapor spectrum, and that magnetograms taken using this line are therefore inaccurate. We investigate the effects of this contamination on the Mount Wilson synoptic magnetograph data, which is based on 5250.2. Using spectrum scans taken at Kitt Peak, we model the contamination and develop a procedure that would correct for it, whenever the slant water vapor along the line of sight to the Sun is known. As this information is not available for the data collected thus far at Mount Wilson, we use the variation of determined quantities with airmass to obtain an average, or first-order, correction. Concentrating on the fitted coefficients for the solar rotation, the correction is found to be very slight, 0.5%, raising the value for the A coefficient, averaged over the period 3 December, 1985 to 22 July, 1990, from 2.8289 to 2.8422 rad s-1, The correction also removes a slight annual variation that has become discernible in the data collected since 1986.Now at Oregon Heath Sciences University, Portland, OR, U.S.A.Now at Department of Astronomy, University of Minnesota, U.S.A. 相似文献
3.
We attempt to correlate all of the available solar-neutrino data with the strong magnetic fields these neutrinos encounter in the solar interior along their Earth-bound path. We approximate these fields using the photospheric, magnetograph-measured flux from central latitude bands, time delayed to proxy the magnetic fields in the solar interior. Our strongest evidence for anticorrelation is for magnetic fields within the central ±5° solar-latitude band that have been delayed by 0.85 ± 0.55 yr. Assuming a neutrino-magnetic interaction, this might indicate that interior fields travel to the solar surface in this period of time. As more solar-neutrino flux information is gathered, the question of whether this result arises from a physical process or is merely a statistical fluke should be resolved, providing that new data are obtained spanning additional solar cycles and that correlation studies focus on these same regions of the solar magnetic field. 相似文献
4.
We explore a systematic error that arises in feature-tracking measurements of time-average rotation. It stems from the flows of features across latitudes, and as these flows vary with the solar activity cycle, the error has a pattern of variation which mocks the torsional oscillation. We develop a series expansion for this error and evaluate the leading terms for the example case of cycle 21. It grows with the time lag; for a 30 day lag it is 1%, depending on how the correlations are done and interpreted. We conclude that the mock pattern cannot, however, account for the magnetic-rotation torsional oscillations pattern found in recent analyses of magnetograms from Kitt Peak and Mount Wilson. For the 1-day time lag in the Kitt Peak study, the error is negligible, and for the 30-day time lag in the Mount Wilson study, it represents at most about 30% of the signal. 相似文献
5.
A Sustainable U.S. Energy Plan 总被引：1，自引：0，他引：1
Herschel Specter 《Natural Resources Research》2009,18(4):285-333
This report gives guidance on what could be done to overcome the political stalemate that has long blocked the creation of
a sustainable energy plan, leaving the United States vulnerable to oil imports while emitting large amounts of greenhouse
gases. An overall energy policy is suggested for use by political leaders, along with specific goals on climate change and
national security. This report proposes a timetable by which the climate change and national security goals should be accomplished.
Converting these political goals into a cost-effective energy plan that would continue to get long-term political support
would be the task of the technical community. A generic process is described which applies to all future energy systems and
would give guidance to the technical community on how to create a mix of energy sources and conservation. This generic process
is then tested on three possible energy futures. One energy future proposes that all of our electricity should come from renewable
sources within 10 years. It is shown to be inadequate and would exacerbate environmental risks. The second possible energy
future adds far more nuclear energy and coal plants with carbon capture and sequestration to the above renewable-only proposal.
This second plan was a significant improvement over the all-renewable energy proposal, but does not address how transportation
might be accomplished in the future. Converting coal to liquid fuels is identified as the major means to produce liquid fuels,
as long as non-carbon dioxide emitting sources of process heat/hydrogen are employed in this coal conversion process. The
third proposal, called an Energy Family approach, places first emphasis on conservation and then creates a mix of energy sources,
renewable, nuclear, coal, natural gas, and some oil that could meet all the energy demands of a modern society, while staying
within environmental and national security limits. This third approach appears to be most likely to get continuing support.
There can be significant progress through “Second Generation” conservation, which extracts much more energy from our existing
electrical generation and transmission system. Coal would have to undergo a major transformation from producing electricity
to producing liquid fuels for transportation. Transportation and space heating and cooling would be far more electrified.
Nuclear power would have to be expanded to replace many of the phased out coal plants, to provide electricity for transportation,
and to supply high-temperature process heat and hydrogen. Long-term programs need to be put in place to assure nuclear power’s
continuing contribution. Finally, energy storage is a component which is often overlooked, but is essential. It could overcome
fundamental renewable energy difficulties of variability and the possibility of wind power to create electrical grid instabilities.
It is shown that an Energy Family approach could accelerate the development of renewable energy. 相似文献
6.
Herschel B. Snodgrass 《Solar physics》1987,110(1):35-49
Both the net torsional pattern and its derivative, the shear oscillation, are studied in relation to the solar activity cycle using data collected at Mount Wilson from 1967–1986. The shear is seen as the better quantity for study, since it is both more fully determinable with these data and has straighter ties to the zones of activity. The shear zones run from pole to equator, clearly indicating that the cycle begins at the poles. Total transit, roughly at constant speed, takes roughly 18 years, and the active zones emerge to span the zones of shear enhancement after the latter have reached sunspot latitudes. This 18-yr transit time is seen as the proper duration of the cycle: successive cycles begin roughly 11 years apart and thus overlap. The polar origin of the torsional pattern is found to be phenomenologically connected with variations in the polar field amplitude. It is also noted in both the magnetic and torsional patterns that, for the past few cycles, the activity portion begins earlier and thus lasts longer in the northern hemisphere.In a general discussion of torsional oscillations and their role in the solar cycle, the net pattern and k = 2 wave interpretations of the torsional phenomenon are contrasted and reasons for preferring the net pattern are presented. A model is proposed in which the torsional oscillations are the surface signature of an azimuthal convective-roll pattern. This model could provide the original Babcock model with a mechanism for trapping and further amplifying the toroidal field.Solar Cycle Workshop Paper. 相似文献
7.
Roger K. Ulrich John E. Boyden Larry Webster Herschel B. Snodgrass Steven P. Padilla Pamela Gilman Tom Shieber 《Solar physics》1988,117(2):291-328
This paper describes a thorough reevaluation of the procedures for reducing the data acquired at the Mt. Wilson Observatory synoptic program of solar observations at the 150-foot tower. We also describe a new program of acquiring as many scans per day as possible of the solar magnetic and velocity fields. We give a new fitting formula which removes the background velocity field from each scan. An important new feature of our reduction algorithm is our treatment of the limb shift which permits time variation in this function. We identify the difference between the limb shift along the north-south axis and the east-west axis as potentially being a result of meridional circulation. Our analysis interprets the time variation in the east-west limb shift as being the result of changes in a vertical component of the meridional circulation.The performance of the system improved in 1982 as a result of the installation of a new exit slit assembly. The amplitude of the limb shift variations found prior to 1982 is larger than is easily explained with simple ideas of meridional circulation. However, we have not been able to firmly identify instrumental causes for the variations although small changes in the band-pass of the exit slit assembly could have contributed.We have established a correlation between the observed stray light in the system and a component of the velocity field which is antisymmetric with respect to the solar central meridian. We remove this stray light effect by adding an additional term to the fitting function.Finally, we show that the inclusion of the above improvements allows us to study the torsional oscillations at high latitude using a procedure which can retain the longitude dependent information about the velocity pattern. 相似文献
8.
Standing wave torsional oscillations of wavenumber 1/2 and 1 hemisphere–1 are studied using an improved fit to Mount Wilson magnetograph data. These oscillations are seen to be in phase with each other and with the magnetic activity cycle, and seem best represented as a flexing of the differential rotation curve. Superposing them gives a differential rotation which at solar minimum is slightly flattened at the equator but considerably ( 5%) steepened at the poles, and also tends to produce a travelling wave with wavenumber 1 hemisphere–1 that moves from pole to equator as the cycle progresses. 相似文献
9.
Herschel B. Snodgrass 《Solar physics》1984,94(1):13-31
Mount Wilson solar Doppler data spanning January 1967 to March 1984 are refit with an expanded set of functions representing the line-of-sight components of rotation, limbshift and meridional flow. The ears are not included, and a constant term, formerly regarded as the relative instrumental zero, is reclassified as representing an aspect of the limbshift. The long-standing problem of crosstalk among the fit-determined coefficients is eliminated by orthonormalization with respect to the solar disk of the function space representing each motion class. Examination of the new coefficients shows clear evidence for their variation over the solar cycle: for the rotation coefficients, this variation is a low mode torsional oscillation, and for the limbshift, it appears consistent with the suppression of small-scale convection by magnetic activity. The meridional flow is found to be poleward and slightly faster at low latitudes. Also seen in all coefficients is a dramatic reduction of day-to-day scatter following recent major modifications to the Mount Wilson 150-ft tower spectrograph. 相似文献
10.
We cross-correlate pairs of Mt. Wilson magnetograms spaced at intervals of 24–38 days to investigate the meridional motions of small magnetic features in the photosphere. Our study spans the 26-yr period July 1967–August 1993, and the correlations determine longitude averages of these motions, as functions of latitude and time. The time-average of our results over the entire 26-yr period is, as expected, antisymmetric about the equator. It is poleward between 10° and 60°, with a maximum rate of 13 m s–1, but for latitudes below ±10° it is markedly equatorward, and it is weakly equatorward for latitudes above 60°. A running 1-yr average shows that this complex latitude dependence of the long-term time average comes from a pattern of motions that changes dramatically during the course of the activity cycle. At low latitudes the motion is equatorward during the active phase of the cycle. It tends to increase as the zones of activity move toward the equator, but it reverses briefly to become poleward at solar minimum. On the poleward sides of the activity zones the motion is most strongly poleward when the activity is greatest. At high latitudes, where the results are more uncertain, the motion seems to be equatorward except around the times of polar field reversal. The difference-from-average meridional motions pattern is remarkably similar to the pattern of the magnetic rotation torsional oscillations. The correspondence is such that the zones in which the difference-from-average motion is poleward are the zones where the magnetic rotation is slower than average, and the zones in which it is equatorward are the zones where the rotation is faster.Our results suggest the following characterization: there is a constant and generally prevailing motion which is perhaps everywhere poleward and varies smoothly with latitude. On this is superimposed a cycle-dependent pattern of similar amplitude in which the meridional motions of the small magnetic features are directed away from regions of magnetic flux concentration. This is suggestive of simple diffusion, and of the models of Leighton (1964) and Sheeley, Nash, and Wang (1987). The correspondence between the meridional motions pattern and the torsional oscillations pattern in the magnetic rotation suggests that the latter may be an artifact of the combination of meridional motion and differential rotation. 相似文献