Academic literature on the topic 'Mathcad, interface'

Objectives. This article is devoted to the problem of processing and analysis of speech signals on the basis of the wavelet transform method, which has become one of the most relevant in recent years.Method. The growing relevance and undoubted practical value became the reason for the emergence of a large number of software systems that allow the processing of speech signals on the basis of this method. However, each of these systems has significant differences in the interface provided by the processing tools, functions, has a number of advantages and disadvantages. At the moment, a large number of manuals and recommendations for specific software packages have been written, but these materials are fragmented and unsystematic.Result. This article attempts to systematize the theoretical material and describe the similarities and differences, advantages and disadvantages of the three most popular software systems: 1) MATLAB 6.0/6.1/6.5 Wavelet Toolbox 2/2.1/2.2; 2) Mathcad; 3) Wavelet Explorer of Mathematica.Conclusion. This article will be useful for specialists dealing with the problem of speech signal processing using the wavelet transform method, as it contains material that has practical value, and will allow to facilitate the work of a specialist related to the selection of the optimal for the implementation of a specific task of the software complex.

The mixing properties of statically stable density interfaces subject to imposed vertical shear are studied using direct numerical simulations of stratified plane Couette flow. The simulations are designed to investigate possible self-maintaining mechanisms of sharp density interfaces motivated by Phillips’ argument (Deep-Sea Res., vol. 19, 1972, pp. 79–81) by which layers and interfaces can spontaneously form due to vertical variations of diapycnal flux. At the start of each simulation, a sharp density interface with the same initial thickness is introduced at the midplane between two flat, horizontal walls counter-moving at velocities$\pm U_{w}$. Particular attention is paid to the effects of varying Prandtl number$\mathit{Pr}\equiv \unicode[STIX]{x1D708}/\unicode[STIX]{x1D705}$, where$\unicode[STIX]{x1D708}$and$\unicode[STIX]{x1D705}$are the molecular kinematic viscosity and diffusivity respectively, over two orders of magnitude from 0.7, 7 and 70. Varying$\mathit{Pr}$enables the system to access a considerable range of characteristic turbulent Péclet numbers$\mathit{Pe}_{\ast }\equiv {\mathcal{U}}_{\ast }{\mathcal{L}}_{\ast }/\unicode[STIX]{x1D705}$, where${\mathcal{U}}_{\ast }$and${\mathcal{L}}_{\ast }$are characteristic velocity and length scales, respectively, of the motion which acts to ‘scour’ the density interface. The dynamics of the interface varies with the stability of the interface which is characterised by a bulk Richardson number$\mathit{Ri}\,\equiv \,b_{0}h/U_{w}^{2}$, where$b_{0}$is half the initial buoyancy difference across the interface and$h$is the half-height of the channel. Shear-induced turbulence occurs at small$\mathit{Ri}$, whereas internal waves propagating on the interface dominate at large$\mathit{Ri}$. For a highly stable (i.e. large$\mathit{Ri}$) interface at sufficiently large$\mathit{Pe}_{\ast }$, the complex interfacial dynamics allows the interface to remain sharp. This ‘self-sharpening’ is due to the combined effects of the ‘scouring’ induced by the turbulence external to the interface and comparatively weak molecular diffusion across the core region of the interface. The effective diapycnal diffusivity and irreversible buoyancy flux are quantified in the tracer-based reference coordinate proposed by Winters & D’Asaro (J. Fluid Mech., vol. 317, 1996, pp. 179–193) and Nakamura (J. Atmos. Sci., vol. 53, 1996, pp. 1524–1537), which enables a detailed investigation of the self-sharpening process by analysing the local budget of buoyancy gradient in the reference coordinate. We further discuss the dependence of the effective diffusivity and overall mixing efficiency on the characteristic parameters of the flow, such as the buoyancy Reynolds number and the local gradient Richardson number, and highlight the possible role of the molecular properties of fluids on diapycnal mixing.

É muito usual a utilização de estruturas de contenção, como muros de gravidade ou flexão, para estabilização de encostas, quando não se é possível a execução de um talude que se mantenha estável por si só, devido às características do solo. Os muros de contenção são usados para conter porções de terra próximas às edificações ou abaixo delas, a fim de garantir sua segurança contra deslizamentos do terrapleno. Os muros de gravidade são os muros de contenção que se mantém estáveis devido ao peso próprio. Tais muros têm o processo de cálculo composto por alguns passos, visto que devem ser verificadas determinadas condições de segurança e fazê-lo de modo manual torna o serviço lento. O presente trabalho visa apresentar um aplicativo para dimensionar os muros de gravidade, constituídos de concreto ciclópico, com o intuito de tornar o trabalho de cálculo mais ágil, que além disso possa ser usado como ferramenta educacional. A princípio foram desenvolvidos roteiros de cálculos de seis perfis de muro, no software PTC Mathcad Express Prime 6.0. O aplicativo foi desenvolvido com a ferramenta MIT App Inventor 2, que utiliza uma programação em blocos, de interface amigável e intuitiva, o que beneficiou no desenvolvimento do aplicativo. De modo a exemplificar e testar a ferramenta, foram dimensionados no aplicativo dois perfis para verificar o mais adequado. Pode-se concluir, que ter os roteiros de cálculo proveu uma ótima base para o desenvolvimento do aplicativo, além disso o aplicativo funcionou como um bom facilitador para dimensionar muros de gravidade, pois só solicitou a escolha de perfil e a inserção de dados fundamentais, reduzindo o tempo de cálculo.

We consider the time-dependent flow of a fluid of density $\unicode[STIX]{x1D70C}_{1}$ in a vertical cylindrical container embedded in a fluid of density $\unicode[STIX]{x1D70C}_{2}~({<}\unicode[STIX]{x1D70C}_{1})$ whose side boundary is suddenly removed and the fluid drains freely from the edge. We show that in the inertial–buoyancy regime (large initial Reynolds number) the flow is modelled by the shallow-water equations and bears similarities to a gravity current released from a lock (the dam-break problem) driven by the reduced gravity $g^{\prime }=(1-\unicode[STIX]{x1D70C}_{2}/\unicode[STIX]{x1D70C}_{1})g$. This formulation is amenable to an efficient finite-difference solution. Moreover, we demonstrate that similarity solutions exist, and show that the flow created by the dam break approaches the predicted self-similar behaviour when the volume ratio ${\mathcal{V}}(t)/{\mathcal{V}}(0)\approx 1/2$ where $t$ is time elapsed from the dam break. We considered two cases of drainage: (i) outward from the outer boundary in a full-radius reservoir; and (ii) inward from the inner radius in an annular-shaped reservoir. For the first case the similarity solution is expressed analytically, while the second case is more complicated and requires a numerical solution. In both cases ${\mathcal{V}}(t)/{\mathcal{V}}(0)$ decays like $t^{-2}$, but the details are different. The similarity solutions admit an adjustable virtual-origin constant, which we determine by matching with the finite-difference solution. The analysis is valid for both Boussinesq and non-Boussinesq systems, and a wide range of geometric parameters (inner and outer radii, and height). The importance of the neglected viscous terms increases with time, and eventually the inertial–buoyancy model becomes invalid. An estimate for this occurrence is also provided. The predictions of the model are compared to results of direct numerical simulations; there is good agreement for the position of the interface and for the averaged radial velocity, and excellent agreement for ${\mathcal{V}}(t)/{\mathcal{V}}(0)$. A box model is used for estimating the effect of a partial (over a sector) dam break. This study is an extension of the work for a rectangular reservoir of Momen et al. (J. Fluid Mech., vol. 827, 2017, pp. 640–663). We demonstrate that there are some similarities, but also significant differences, between the rectangular and the cylindrical reservoirs concerning the velocity, shape of the interface and rate of drainage, which are of interest in applications. The overall conclusion is that this simple model captures very well the flow field under consideration.