9,145 research outputs found
Normal heat conduction in one dimensional momentum conserving lattices with asymmetric interactions
The heat conduction behavior of one dimensional momentum conserving lattice
systems with asymmetric interparticle interactions is numerically investigated.
It is found that with certain degree of interaction asymmetry, the heat
conductivity measured in nonequilibrium stationary states converges in the
thermodynamical limit, in clear contrast to the well accepted viewpoint that
Fourier's law is generally violated in low dimensional momentum conserving
systems. It suggests in nonequilibrium stationary states the mass gradient
resulted from the asymmetric interactions may provide an additional phonon
scattering mechanism other than that due to the nonlinear interactions.Comment: 4 pages, 4 figure
Study on the design schemes of marine warning and forecasting system platform
The system platform of marine monitoring and disaster forecasting plays an important role in ocean observations, data collection as well as disaster prevention and mitigation. This paper discusses the necessity and significance of the system platform construction in Jiangsu Province, China. We take the construction of the observation platform as an example, considering the difficulties of the project design, analyzed the influence factors like wind, water level, tide, wave, earthquake and corrosion. On the basis, we study the platform???s program layout, hydraulic structures scheme, layout of main observation devices, power supply and lightning, construction scheme. The research results can provide a reference for the design of the subsequent ocean observing platform, and can be further applied in other related design of observation platform
Morphological Dependence of MIR Properties of SDSS Galaxies in the Spitzer SWIRE Survey
We explore the correlation between morphological types and mid-infrared (MIR)
properties of an optically flux-limited sample of 154 galaxies from the Forth
Data Release (DR4) of Sloan Digital Sky Survey (SDSS), cross-correlated with
Spitzer SWIRE (Spitzer Wide-Area InfraRed Extragalactic Survey) fields of
ELAIS-N1, ELAIS-N2 and Lockman Hole. Aperture photometry is performed on the
SDSS and Spitzer images to obtain optical and MIR properties. The morphological
classifications are given based on both visual inspection and bulge-disk
decomposition on SDSS g- and r-band images. The average bulge-to-total ratio
(B/T) is a smooth function over different morphological types. Both the
8um(dust) and 24um(dust) luminosities and their relative luminosity ratios to
3.6um (MIR dust-to-star ratios) present obvious correlations with both the
Hubble T-type and B/T. The early-type galaxies notably differ from the
late-types in the MIR properties, especially in the MIR dust-to-star ratios. It
is suggested that the MIR dust-to-star ratio is an effective way to separate
the early-type galaxies from the late-type ones. Based on the tight correlation
between the stellar mass and the 3.6um luminosity, we have derived a formula to
calculate the stellar mass from the latter. We have also investigated the MIR
properties of both edge-on galaxies and barred galaxies in our sample. Since
they present similar MIR properties to the other sample galaxies, they do not
influence the MIR properties obtained for the entire sample.Comment: Accepted for publication by AJ. 18 pages, 14 figures, and 4 table
Variations of stomatal frequency in Taxodium and Metasequoia populations at the mid-Miocene Clarkia Lake deposits: Implications for atmospheric CO2 reconstruction
Stomatal frequency (such as stomatal index-SI and stomatal density-SD) has been widely used to reconstruct atmospheric CO2 levels in geological history as it is one of the most reliable proxies of paleo-CO2 that predate the oldest icecore records. However, living plants show large variations on stomatal frequency within the same species, potentially generating large error margins for estimated paleo-CO2 levels using limited fossil specimen(s). The extraordinarily wellpreserved and abundant fossil leaves from the mid-Miocene (~15Ma) Clarkia Lake deposits in northern Idaho, the USA, allow us to test variations within a population of a fossil species and to compare that cross different contemporary species. Our preliminary results from the SD of 15 cuticular membranes of Taxodium revealed a range of variation leading to CO2 levels of 345-445 parts per million (ppm). The SI of eight cuticular membranes of Metasequoia from the same fossiliferous layers reconstructed CO2 levels of 290-345 ppm. These wide and discrepant ranges imply that randomly selected fossil leaves with limited sample numbers may give a large range of CO2 reconstructions and different methods (such as SD or SI) and different plant taxa (such as Taxodium and Metasequoia) may result in different CO2 results. A better understanding of stomatal frequency variations within populations and consistent sampling method will reduce errors in paleo-CO2 reconstruction
Comparison of Direct vs. Indirect Ventilation Rate Determination for Manure Belt Laying Hen Houses
Direct measurement of ventilation rate in livestock housing can be a formidable task due to uncontrollable variations in fan and system performance as caused by factors such as operation static pressure, fan belt condition, and dust accumulation on shutters and blades. Indirect, CO2-balance method offers a potentially viable, more flexible alternative to estimating ventilation rate. The reliability of CO2 balance method depends on the validity of relationship between CO2 production and metabolic rate of the animals and the knowledge of CO2 generation by the housing environment. Metabolic rates of modern laying hens have recently been quantified in intensive large-scale laboratory measurements. However, performance of the indirect method remains to be evaluated under field production conditions. This paper compares ventilation rates of a commercial laying hen house with manure belt (manure removed daily) obtained from direct measurement based on in-situ fan performance and runtime vs. indirect determination based on CO2 balance. The results indicate that indirect determination based on CO2 balance was well in agreement with that of direct measurement. Application of the CO2-balance method to evaluate building ventilation rate can improve the affordability and versatility of poultry emission studies
Comparison of Direct vs. Indirect Ventilation Rate Determinations in Layer Barns using Manure Belts
Direct measurement of building ventilation rate in livestock housing is a formidable task due to uncontrollable variations in fan and system performance that are caused by factors such as building static pressure, fan belt slippage, and dust accumulation on shutters and blades. Estimating building ventilation rate by an indirect method based on a CO2 balance offers a potentially viable alternative to direct measurement. The validity of the CO2 balance method depends on the validity of relationship between CO2 production inside the building and metabolic rate of the animals and the knowledge of CO2 generation by the housing environment. Metabolic rates of modern laying hens have recently been quantified in intensive large-scale laboratory measurements. However, performance of the indirect method remains to be evaluated under field conditions. This article compares building ventilation rates obtained by direct measurement and by a CO2 balance. The test was conducted at a commercial laying hen house that used manure belts with daily manure removal. The results indicate that ventilation rates estimated by the indirect method were not significantly different (P \u3e 0.2) from those as determined by the direct measurement when the averaging or integration time interval was 2 h or longer. Careful application of the indirect method could greatly improve the affordability and versatility of endeavors toward quantifying air emissions from confined animal housing
Statistical Origin of Constituent-Quark Scaling in the QGP hadronization
Nonextensive statistics in a Blast-Wave model (TBW) is implemented to
describe the identified hadron production in relativistic p+p and
nucleus-nucleus collisions. Incorporating the core and corona components within
the TBW formalism allows us to describe simultaneously some of the major
observations in hadronic observables at the Relativistic Heavy-Ion Collider
(RHIC): the Number of Constituent Quark Scaling (NCQ), the large radial and
elliptic flow, the effect of gluon saturation and the suppression of hadron
production at high transverse momentum (pT) due to jet quenching. In this
formalism, the NCQ scaling at RHIC appears as a consequence of non-equilibrium
process. Our study also provides concise reference distributions with a least
chi2 fit of the available experimental data for future experiments and models.Comment: 4 pages, 3 figures; added two tables, explained a little bit more on
TBW_p
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