4E assessment of power generation systems for a mobile house in emergency condition using solar energy: a case study

Journal of Thermal Analysis and Calorimetry - This contribution experimentally and analytically addresses the dripping and ignition mechanism of vertically discrete polypropylene (PP) and...     

Random maximal independent sets and the unfriendly theater seating arrangement problem

People arrive one at a time to a theater consisting of m rows of length n. Being unfriendly they choose seats at random so that no one is in front of them, behind them or to either side. What is the expected number of people in the theater when it becomes full, i.e., it cannot accommodate any more unfriendly people? This is equivalent to the random process of generating a maximal independent set of an m×n grid by randomly choosing a node, removing it and its neighbors, and repeating until there are no nodes remaining. The case of m=1 was posed by Freedman and Shepp [D. Freedman, L. Shepp, An unfriendly seating arrangement (problem 62-3), SIAM Rev. 4 (2) (1962) 150] and solved independently by Friedman, Rothman and MacKenzie [H.D. Friedman, D. Rothman, Solution to: An unfriendly seating arrangement (problem 62-3), SIAM Rev. 6 (2) (1964) 180-182; J.K. MacKenzie, Sequential filling of a line by intervals placed at random and its application to linear adsorption, J. Chem. Phys. 37 (4) (1962) 723-728] by proving the asymptotic limit . In this paper we solve the case m=2 and prove the asymptotic limit . In addition, we consider the more general case of m×n grids, m≥1, and prove the existence of asymptotic limits in this general setting. We also make several conjectures based upon Monte Carlo simulations.     

Quantum mechanical studies on the singlet and triplet potential energy surface of the reactions CF3O2 + I,CF3O + OI and CF3 + OIO

The singlet and triplet potential energy surfaces for the reactions CF₃O₂ + I (1), CF₃O + OI (2) and CF₃ + OIO (3) are investigated using ab initio quantum mechanical methods. Four important isomeric energy minima were found, three on the singlet surface, CF₃OOI, CF₃OIO and CF₃IO₂ and one on the triplet surface ³CF₃OIO. CF₂O + FOI are shown to be the most probable products for all reactions, CF₃O +I and CF₃O + O(³P) are possible for reactions (2) and (3) while the reaction pathway leading to CF₃O +OI is also possible for reaction (3).     

Stability and Spectral Comparison of a Reaction–Diffusion System with Mass Conservation

We study the global-in-time behavior of solutions to a reaction–diffusion system with mass conservation, as proposed in the study of cell polarity, particularly, the second model of the work by Otsuji et al. (PLoS Comput Biol 3:e108, 2007). First, we show the existence of a Lyapunov function and confirm the global-in-time existence of the solution with compact orbit. Then we study the stability and instability of stationary solutions by using the semi-unfolding-minimality property and the spectral comparison. As a result the dynamics near the stationary solutions is qualitatively characterized by a variational function.     

Periodic solutions of a singularly perturbed delay differential equation

A singularly perturbed differential delay equation of the form

(1)     

The Modified Magnetohydrodynamical Equations

After finding the really self-consistent electromagnetic equations for a plasma, we proceed in a similarfashion to find how the magnetohydrodynamical equations have to be modified accordingly. Substantially this is doneby replacing the “Lorentz“ force equation by the correct (in our case) force equation. Formally we have to use the vectorpotential instead of the magnetic field intensity. The appearance of the formulae presented is the one of classical vectoranalysis. We thus find a set of eight equations in eight unknowns, as previously known concerning the traditional MHDequations.     

Monitoring of time variation and effect of some meteorological parameters in polynuclear aromatic hydrocarbons in Ioannina, Greece with the aid of HPLC-fluorescence analysis

This paper describes the monitoring of 16 polynuclear aromatic hydrocarbons (PAH) in the suspended particulate matter in the area of Ioannina. A total of 244 samples were collected from five locations throughout the city. These samples were analyzed in order to acquire a complete picture of the PAH abundance and distribution above the city of Ioannina. The sampling sites covered the center of the city as well as the suburban territory. The monitoring lasted for one year starting in November 1996. Higher values of PAH were found at the sites surrounding the city center, while at the rest of the area the concentration of PAH was substantially lower. The effect of ambient temperature and humidity on PAH abundance and distribution was also evaluated. As a result it was revealed that higher concentrations of PAH are favored by low temperatures and high values of humidity. Regarding the seasonal variation of PAH it was found that their concentrations are elevated during the winter months where heating systems are operating. On a daily basis it appears that the highest abundances of PAH occur on Wednesdays while the lowest on Sundays. The mean yearly concentration values of benzo[a]pyrene varied between 0.32+/-0.02 and 2.63+/-0.08 ng m(-3) for the various sites. Compared with the reported values the PAH levels in the area of Ioannina can be characterized as medium to low.     

Phosphonate ligands encourage a platonic relationship between cobalt(II) and alkali metal ions

Two new cobalt(ii) cages are reported where the metal core has a high symmetry related to a Platonic solid; the choice of alkali metal used in the base used for deprotonation appears to influence the resulting structures.     

Electronic structure of vanadium oxide. Neutral and charged species, VO0,+/-

The diatomic molecule vanadium oxide, VO, and its charged species VO+ and VO- were studied by multireference and coupled cluster methods in conjunction with large basis sets. The investigation of 22 states and the construction of 21 full potential energy curves allowed for a detailed understanding of the electronic structure of these species. Our best binding energies for the ground states of VO (X4Sigma-), VO+ (X3Sigma-), and VO- (X3Sigma-) were De = 150, 138, and 143 kcal/mol, respectively, in harmony with the corresponding experimental values. For both species VO and VO+ and for all states studied, the bonding showed a strong ionic character conforming to the models V+O- and V2+O-.     

9-Substituted acridines. Demethoxylation of 9-methoxyacridine and dechlorination of 9-chloroacridine in hydroxylic solvents

In methanol-water mixtures containing sodium or potassium hydroxide (up to 2.00M) the demethoxylation of 9-methoxyacridine to 9-acridone is of first order in both the free form of 9-methoxyacridine and the hydroxyl ion. The rate of the reaction is increased with an increase in the concentration of water. Sodium perchlorate has a small retarding effect on the reaction. In methanol-water mixtures containing perchloric or hydrochloric acid (up to 3.45M) the demethoxylation is of first order with respect to the protonated form of 9-methoxyacridine. The rate of the reaction decreases with an increase in the concentration of the acid or of sodium perchlorate, but when the concentration of water is increased (≈?1.7 to 50M) and that of the acid is not changed, it reaches a maximum value in mixtures containing 8 to 10M-water. The dechlorination of 9-chloroacridine to 9-methoxyacridine in methanol containing sodium hydroxide or methoxide (up to 0.31 M) is of first order in both the 9-chloroacridine and the hydroxyl or methoxyl ions.