An official website of the United States government
Abstract The thermal conductivity of many materials depends on temperature due to several factors, including variation of heat capacity with temperature, changes in vibrational dynamics with temperature, and change in volume with temperature. For proteins some, but not all, of these influences on the variation of thermal conductivity with temperature have been investigated in the past. In this study, we examine the influence of change in volume, and corresponding changes in vibrational dynamics, on the temperature dependence of the thermal conductivity. Using a measured value for the coefficient of thermal expansion and recently computed values for the Grüneisen parameter of proteins we find that the thermal conductivity increases with increasing temperature due to change in volume with temperature. We compare the impact of thermal expansion on the variation of the thermal conductivity with temperature found in this study with contributions of heat capacity and anharmonic coupling examined previously. Using values of thermal transport coefficients computed for proteins we also model heating of water in a protein solution following photoexcitation.
more »
« less
Four-Parameter Coalescing Ballistic Annihilation
In coalescing ballistic annihilation, infinitely many particlesmove with fixed velocities across the real line and, upon colliding, either mutually annihilate or generate a new particle. We compute the critical density in symmetric three-velocity systems with four-parameter reaction equations.
more »
« less
- PAR ID:
- 10535224
- Publisher / Repository:
- Springer
- Date Published:
- Journal Name:
- Journal of Statistical Physics
- Volume:
- 191
- Issue:
- 7
- ISSN:
- 1572-9613
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
null (Ed.)The Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) temperature measurements at low latitudes from 89 km to 97 km were used to derive the F10.7 and Ap index trends, and the trends were compared to model simulations. The annual mean nonzonal (e.g., at the model simulation location at 18° N, 290° E) SABER temperature showed a good-to-moderate correlation with F10.7, with a trend of 4.5–5.3 K/100 SFU, and a moderate-to-weak correlation with the Ap index, with a trend of 0.1–0.3 K/nT. The annual mean zonal mean SABER temperature was found to be highly correlated with the F10.7, with a similar trend, and moderately correlated with the Ap index, with a trend in a similar range. The correlation with the Ap index was significantly improved with a slightly larger trend when the zonal mean temperature was fitted with a 1-year backward shift in the Ap index. The F10.7 (Ap index) trends in the simulated O2 and the O(1S) temperature were smaller (larger) than those in the annual mean nonzonal mean SABER temperature. The trends from the simulations were better compared to those in the annual mean zonal mean temperature. The comparisons were even better when compared to the trend results obtained from fitting with a backward shift in the Ap index.more » « less
-
null (Ed.)Abstract This study revisits the superintensity of tropical cyclones (TCs), which is defined as the excess maximum surface wind speed normalized by the corresponding theoretical maximum potential intensity (MPI), based on ensemble axisymmetric numerical simulations, with the focus on the dependence of superintensity on the prescribed sea surface temperature (SST) and the initial environmental atmospheric sounding. Results show a robust decrease of superintensity with increasing SST regardless of being in experiments with an SST-independent initial atmospheric sounding or in those with the SST-dependent initial atmospheric soundings as in nature sorted for the western North Pacific and the North Atlantic. It is found that the increase in either convective activity (and thus diabatic heating) in the TC outer region or theoretical MPI or both with increasing SST could reduce the superintensity. For a given SST-independent initial atmospheric sounding, the strength of convective activity in the TC outer region increases rapidly with increasing SST due to the rapidly increasing air–sea thermodynamic disequilibrium (and thus potential convective instability) with increasing SST. As a result, the decrease of superintensity with increasing SST in the SST-independent sounding experiments is dominated by the increasing convective activity in the TC outer region and is much larger than that in the SST-dependent sounding experiments, and the TC intensity becomes sub-MPI at relatively high SSTs in the former. Due to the marginal increasing tendency of convective activity in the TC outer region, the decrease of superintensity in the latter is dominated by the increase in theoretical MPI with increasing SST.more » « less
-
Social insect colonies’ robust and efficient collective behaviors without any central control contribute greatly to their ecological success. Colony migration is a leading subject for studying collective decision-making in migration. In this paper, a general colony migration model with Hill functions in recruitment is proposed to investigate the underlying decision making mechanism and the related dynamical behaviors. Our analysis provides the existence and stability of equilibrium, and the global dynamical behavior of the system. To understand how piecewise functions and Hill functions in recruitment impact colony migration dynamics, the comparisons are performed in both analytic results and bifurcation analysis. Our theoretical results show that the dynamics of the migration system with Hill functions in recruitment differs from that of the migration system with piecewise functions in the following three aspects: (1) all population components in our colony migration model with Hill functions in recruitment are persistent; (2) the colony migration model with Hill functions in recruitment has saddle and saddle-node bifurcations, while the migration system with piecewise functions does not; (3) the system with Hill functions has only equilibrium dynamics, i.e. either has a global stability at one interior equilibrium or has bistablity among two locally stable interior equilibria. Bifurcation analysis shows that the geometrical shape of the Hill functions greatly impacts the dynamics: (1) the system with flatter Hill functions is less likely to exhibit bistability; (2) the system with steeper functions is prone to exhibit bistability, and the steady state of total active workers is closer to that of active workers in the system with piecewise function.more » « less
-
This article deals with relationships and marriages of the Tlingit with immigrants from the Russian Empire as well as with representatives of other European and non-European peoples during the period when Alaska belonged to the Russian Empire. Matrimonial relations existed in two variants: legal, sanctified by the church, and in the form of permanent extramarital cohabitation or casual relationships. The latter variant absolutely predominated. With this, there was a sharply reflected gender imbalance, since men absolutely predominated among the immigrants, and therefore Tlingit women emerged in the role of marriage partners in the overwhelming majority of cases. A directly opposite pattern was observed in Tlingit contacts with the Athapaskans and to some extent with the Eyak. Matrimonial connections exerted influence on the workings of the Russian colonization, stimulated growth in mixed populations, and facilitated gradual acculturation of the Tlingit, along with contributing to the expansion of their ethnic territory.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1007/s10955-024-03305-9
