Theoretical substantiation choice of “comfortable” air temperature in industrial premises

In this paper solved the heat conduction problem for the system - the object of heat - insulation - environment (indoor air) considering natural convection. New variant substantiation of a choice the room temperature is proposed based on mathematical modelling

Índices de capacidade de relações funcionais lineares e não-lineares Capability index for linear and non-linear functions

São apresentados métodos para determinação dos índices de capacidade tais como Cp e Cpk aplicados no "design for six sigma" (DFSS) quando a característica de qualidade é não-observável e dada por Y = f(X1, X2, X3,....Xk), onde Xi são variáveis aleatórias com média e variância respectivamente iguais a miXi e sigma2Xi; f é uma função conhecida. A determinação é baseada na série de Taylor e o procedimento será ilustrado com exemplos práticos.<br>Here we present methods to determine capabilit indices such as Cp and Cpk to be applied in "design for six sigma" (DFSS) when the quality characteristic of interest Y is unobservable but given by Y = f(X1, X2, X3,....Xk), where Xi's are random variables with means and variance respectively equal to muXi and sigma2Xi; f is a known function. The determination is based on Taylor series and we illustrate the procedure with practical examples

On the viscosity influence on a helical vortex flament evolution

Helical vortices whose parameters have a strong influence on the efficiency of the apparatus is often occur in technical devices using swirling flow (cyclones, separators, etc.). To date the internal structure of such vortices is poorly understood. In [1] a model of helical vortex with uniform vorticity distribution in the core is proposed. Vortices arising in real flow always have a smooth vorticity distribution due to the viscosity action. The problem on steady moving helical vortices with the vortex core of small size in an inviscid fluid was solved in [2]. The non-orthogonal ‘helical’ coordinate system was introduced that allowed author to reduce the problem to two dimensional one. However, the velocity of the vortex motion was written only in the form of a quadratures computation of which is difficult. This paper presents first attempt for research on the diffusion and dynamics of a viscous helical vortex