A Note on Homoclinic Orbits for Second Order Hamiltonian Systems

In this paper, we study the existence for the homoclinic orbits for the second order Hamiltonian systems. Under suitable conditions on the potential $V$, we apply the direct method of variations and the Fourier analysis to prove the existence of homoclinc orbits

Co2 Adsorption On Solid Sorbents

Sorbent-based CO2 capture technology is considered as one of the potential scientific techniques for mitigating greenhouse gas emission. Major advantages of sorbent based adsorption are its low regeneration energy coupled with the elimination of corrosion and equipment degradation characteristic of amine based solvent CO2 capture systems which are the preferred industrial methods. Different CO2 capture configurations, processes, and operational parameters for different sorbents were revieand summarized. Efficient industrial applications for CO2 capture require that solid sorbents possess an adsorption capacity between 1000-2000µmol/g or more together with a long-term regeneration capacity. Economical consideration necessitates that the cost of CO2 sequestration be less than $10 per ton of CO2. Scientific literature identifies various kinds of sorbents, examples include: activated carbon, modified activated carbon, zeolite, metal-organic framework (MOF) and amine grafted sorbents on silica support. Literature review reveals that amine-grafting process can boost CO2 adsorption on silane sorbent support. The larger surface area of the sorbent support means a greater number of active sites available for grafting which results in a higher CO2 adsorption capacity. The presence of water vapor in the gas stream during grafting and/or during CO2 adsorption can also improve CO2 adsorption of amine-grafted sorbents. Huang reported that MCM-48 silica grafted with 3-aminopropyltriethoxysilane had the greatest CO2 adsorption capacity under anhydrous conditions with 2.30mmol/g sorbent. While Harlick reported that TRI-PE-MCM-41 had the greatest CO2 adsorption capacity under wet conditions with 2.94mmol/g sorbent

Some results on condition numbers of the scaled total least squares problem

AbstractUnder the Golub–Van Loan condition for the existence and uniqueness of the scaled total least squares (STLS) solution, a first order perturbation estimate for the STLS solution and upper bounds for condition numbers of a STLS problem have been derived by Zhou et al. recently. In this paper, a different perturbation analysis approach for the STLS solution is presented. The analyticity of the solution to the perturbed STLS problem is explored and a new expression for the first order perturbation estimate is derived. Based on this perturbation estimate, for some STLS problems with linear structure we further study the structured condition numbers and derive estimates for them. Numerical experiments show that the structured condition numbers can be markedly less than their unstructured counterparts

On a Periodic Solution of the 4-Body Problems

We study the necessary and sufficient conditions on the masses for the periodic solution of planar 4-body problems, where three particles locate at the vertices of an equilateral triangle and rotate with constant angular velocity about a resting particle. We prove that the above periodic motion is a solution of Newtonian 4-body problems if and only if the resting particle is at the origin and the masses of the other three particles are equal and their angular velocity satisfies a special condition

A hepatitis E outbreak by genotype 4 virus in Shandong province, China

AbstractHepatitis E vaccine was available in China in 2012, but the priority population for immunization is not clear. In 2013, a hepatitis E outbreak occurred in a company of Shandong province, China where most employees moved from other provinces and dined at the company’s cafeteria. A total of fourteen (19%, 14/73) case-patients were identified, and three of them had symptomatic infection with one death. The proportion of symptomatic infection was much higher among those aged ⩾50years than those aged <50years (2/2 vs. 1/12, P=0.03), and higher in males than females (3/8 vs. 0/6, P=0.21). Food in the company’s cafeteria might be the possible source of the outbreak. The findings from this outbreak investigation indicate that individuals aged ⩾50years, particularly males, might be the population of top priority for hepatitis E vaccination in China