Products of finite groups and nonmeasurable subgroups

It is proven that if $G$ is a finite group, then $G^\omega$ has $2^{\mathfrak c}$ dense nonmeasurable subgroups. Also, other examples of compact groups with dense nonmeasurable subgroups are presented.Comment: 5 page

Spectral analysis of the biharmonic operator subject to Neumann boundary conditions on dumbbell domains

We consider the biharmonic operator subject to homogeneous boundary conditions of Neumann type on a planar dumbbell domain which consists of two disjoint domains connected by a thin channel. We analyse the spectral behaviour of the operator, characterizing the limit of the eigenvalues and of the eigenprojections as the thickness of the channel goes to zero. In applications to linear elasticity, the fourth order operator under consideration is related to the deformation of a free elastic plate, a part of which shrinks to a segment. In contrast to what happens with the classical second order case, it turns out that the limiting equation is here distorted by a strange factor depending on a parameter which plays the role of the Poisson coefficient of the represented plate.Comment: To appear in "Integral Equations and Operator Theory

KCS34 evaluation for WHR in cement industry

The simple Kalina cycle system 34 (KCS34)- has been studied to perform energy cogeneration from the waste heat recovery (WHR) in preheater cement industries. The preheater available energy was considered from a 5000 tc/day cement production capacity. Thermodynamic and simplified exergoeconomic models were developed in the Engineering Equation Solver (EES) software. Several cycle thermodynamic parameters as ammonia-water mixture concentration and turbine operating pressure were wide-ranging in order to maximize the cycle thermal efficiency aiming to minimize the electricity generation cost. The temperature-entropy KCS34schematics were shown for different best results aiming to understand which set of parameters targets the maximum KCS34performance. The produced power, the thermal cycle efficiency, the exergetic efficiency and the exergoeconomic electricity specific cost were plotted for the different ranges of the independent parameters. The optimum results for a range specific investment price were presented. The main conclusions indicate that in the range of the studied parameters the turbine operating pressure caused a generated power variation greater than the ammonia-water mixture concentration in the KCS34performance. It was also possible to conclude that the KCS34is competitive with the existing electricity prices. In this case the KC proved to be applicable for WHR in the cement industry

When a totally bounded group topology is the Bohr Topology of a LCA group

We look at the Bohr topology of maximally almost periodic groups (MAP, for short). Among other results, we investigate when a totally bounded abelian group $(G,w)$ is the Bohr reflection of a locally compact abelian group. Necessary and sufficient conditions are established in terms of the inner properties of $w$. As an application, an example of a MAP group $(G,t)$ is given such that every closed, metrizable subgroup $N$ of $bG$ with $N \cap G = \{0\}$ preserves compactness but $(G,t)$ does not strongly respects compactness. Thereby, we respond to Questions 4.1 and 4.3 in [comftrigwu]

Modeling the water-halide ion interactions

1 pág.; 1 fig.; XXIX International Conference on Photonic, Electronic, and Atomic Collisions (ICPEAC2015); Open Access funded by Creative Commons Atribution Licence 3.0Ions play an important role in many heterogeneous processes, and understanding specific ion effects is a key point in studying solvation mechanisms in liquids as well as reactivity of aerosol particles. In this regard, a crucial issue to be resolved is the extent to which ions influence the structural and dynamical properties of the surrounding hydrogen bond network and, at the same time, to provide a direct molecular-level interpretation of the experimental measurements.Peer Reviewe

AN EXERGY COST ANALYSIS OF A COGENERATION PLANT

The exergy analysis, including the calculation of the unit exergetic cost of all flows of the cogeneration plant, was the main purpose of the thermoeconomic analysis of the STAG (STeam And Gas) combined cycle CHP (Combined Heat and Power) plant. The combined cycle cogeneration plant is composed of a GE10 gas turbine (11250 kW) coupled with a HRSG (Heat Recovery Steam Generator) and a condensing extraction steam turbine. The GateCycleTM Software was used for the modeling and simulation of the combined cycle CHP plant thermal scheme, and calculation of the thermodynamic properties of each flow (Mass Flow, Pressure, Temperature, Enthalpy). The entropy values for water and steam were obtained from the Steam Tab software while the entropy and exergy of the exhaust gases were calculated as instructed by. For the calculation of the unit exergetic cost was used the neguentropy and Structural Theory of Thermoeconomic. The GateCycleTM calculations results were exported to an Excel sheet to carry out the exergy analysis and the unit exergetic cost calculations with the thermoeconomic model that was created for matrix inversion solution. Several simulations were performed varying separately five important parameters: the Steam turbine exhaust pressure, the evaporator pinch point temperature, the steam turbine inlet temperature, Rankine cycle operating pressure and the stack gas temperature to determine their impact in the recovery cycle heat exchangers transfer area, power generation and unit exergetic cost

Dynamic Characterization of Periodic Lattice of Elastically-connected Bi-stable Elements under Seismic Excitation

Metamaterials are engineered materials, typically in periodic arrangements, which exhibit unconventional or extreme properties not found in nature. Understanding the dynamics of metamaterials enables the design of structures with specific functionalities. The dynamics of metamaterials in linear regime has been relatively well studied in recent years, however the unique phenomena arising from nonlinearities in metamaterials are yet to be explored. In this paper, we focus on an array of bi-stable elements connected by elastic springs under various forms of external excitations acting on the entire system. The general equations of motion are derived to handle any degree-of-freedom (DoF) systems of interest. The MATLAB-based code is developed using finite difference method to solve numerically the system of equations and is validated through the correlation studies with the analytical solutions in previously known linear systems. Numerical investigations are performed on 2-DoF and infinitely-long systems under various excitation levels with focuses on nonlinear responses. The predicted behaviors are experimentally verified from the dynamic testing, using 3D-printed lattice samples