The Boltzmann equation for inelastic and rough hard spheres is considered as a model of a dilute granular gas. In this model, the collisions are characterized by constant coefficients of normal and tangential restitution, and hence the translational and rotational degrees of freedom are coupled. A normal solution to the Boltzmann equation is obtained by means of the Chapman-Enskog method for states near the homogeneous cooling state. The analysis is carried out to first order in the spatial gradients of the number density, the flow velocity, and the granular temperature. The constitutive equations for the momentum and heat fluxes and for the cooling rate are derived, and the associated transport coefficients are expressed in terms of the solutions of linear integral equations. For practical purposes, a first Sonine approximation is used to obtain explicit expressions of the transport coefficients as nonlinear functions of both coefficients of restitution and the moment of inertia. Known results for purely smooth inelastic spheres and perfectly elastic and rough spheres are recovered in the appropriate limits.
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http://dx.doi.org/10.1103/PhysRevE.90.022205 | DOI Listing |
Int J Environ Health Res
January 2025
Guangdong Provincial Engineering Technology Research Center of Environmental Pollution and Health Risk Assessment, Department of Occupational and Environmental Health, School of Public Health, Sun Yat-sen University, Guangzhou, China.
Few epidemiological studies have investigated associations between anthropogenic heat emissions (AE) and serum lipids. We recruited 15,477 adults from 33 communities in northeastern China in 2009. We estimated AE flux by using data on energy consumption and socio-economic statistics covering building, transportation, industry, and human metabolism.
View Article and Find Full Text PDFAnal Methods
November 2017
Agricultural and Biological Engineering Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA.
Nitric oxide (NO) is an important signaling molecule that is involved in stress response, homeostasis, host defense, and cell development. In most cells, NO levels are in the femtomolar to micromolar range, with extracellular concentrations being much lower. Thus, real time measurement of spatiotemporal NO dynamics near the surface of living cells/tissues is a major challenge.
View Article and Find Full Text PDFBMC Res Notes
January 2025
Non-Communicable Diseases Research Center, Department of Epidemiology, School of Health, Shiraz University of Medical Sciences, Shiraz, Iran.
Background: Thyroid cancer is one of the most common cancers of the endocrine system. The incidence of this cancer has increased in many countries. Many cases of thyroid cancer do not have any symptoms.
View Article and Find Full Text PDFSci Rep
January 2025
Center for Research of the Aging Workforce, University of Occupational and Environmental Health, Japan, Kitakyushu, Japan.
Improving physical balance among older workers is essential for preventing falls in workplace. We aimed to elucidate the age-related decline in one-leg standing time with eyes closed, an indicator of static balance, and mitigating influence of daily walking habits on this decline in Japan. This longitudinal study involved 249 manufacturing workers, including seven females, aged 20-66 years engaged in tasks performed at height in the aircraft and spacecraft machinery industry.
View Article and Find Full Text PDFACS Nano
January 2025
Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
Understanding energy transport in semiconductors is critical for the design of electronic and optoelectronic devices. Semiconductor material properties, such as charge carrier mobility or diffusion length, are commonly measured in bulk crystals and determined using models that describe transport behavior in homogeneous media, where structural boundary effects are minimal. However, most emerging semiconductors exhibit nano- and microscale heterogeneity.
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