Effect of Non-uniform Temperature Gradient on Marangoni Convection in a Relatively Hotter or Cooler Layer of Liquid

The effect of non-uniform temperature gradient on the onset of convection driven by surface tension gradients in a relatively hotter or cooler layer of liquid is studied by means of linear stability analysis. the upper boundary is considered to be free and insulating where surface tension gradients arise on account of variation in temperature and the lower boundary is rigid. the single-term Galerkin technique is used to obtain the eigenvalue equation. Eigenvalues are obtained and presented for both thermally conducting and insulating cases of the lower boundary. this analysis predicts that in either case the critical eigenvalues for different non-uniform temperature gradients are greater in a relatively hotter layer of liquid than the cooler one under identical conditions otherwise. this qualitative effect is quite significant quantitatively as well

Through-life integration using PLM

Organised by: Cranfield UniversityIt is widely agreed that organisations would benefit from a PLM implementation founded on a standard structure that integrates through-life information and knowledge. Thus, this paper describes a PLM data structure that provides a standard repository of data through all the stages of the lifecycle: conception, manufacture, and operation. This structure classifies the data into project, product, process and resource, and has been implemented into the PDM system Teamcenter Engineering as part of a case study with a vacuum pump manufacturer. A methodology to implement a knowledge structure from an ontology editor into PDM system is also presented.Mori Seiki – The Machine Tool Compan

A knowledge management framework to support product-service systems design

This paper presents a framework for knowledge reuse in a Product-Service Systems design scenario. The project aim is to develop a methodology to capture, represent and reuse knowledge to support product development in a collaborative enterprise context. The three core elements are: design knowledge, manufacturing capability knowledge, and service knowledge. There are three principal components of the proposed methodology. The first is a process based design model: defining design according to specific tasks, and associating previous knowledge with those tasks. The second is manufacturing capability knowledge: supporting feature based design and manufacture through representing machining features, best practices in machining and inspection, and machining capability. The third component is service knowledge: ensuring that design takes account of the service requirement. The developing paradigm of Product-Service Systems and the requirement for co-design of products and services has influenced the structure of the knowledge base, as well as outlining specific service related requirements. This paper presents the proposed knowledge base structure along with a detailed case study in which the proposal was developed and validated

Simultaneous RPHPLC Determination of Nitazoxanide and Ofloxacin in Combined Tablet Dosage Form

A simple, precise, accurate, rapid and reproducible reverse phase high performance liquid chromatographic procedure was developed for simultaneous determination of nitazoxanide and ofloxacin in tablet dosage form at a single wavelength. The mobile phase used was a combination of acetonitrile:0.25M potassium dihydrogen phosphate buffer (80:20) with 0.5%v/v of triethylamine and the pH was adjusted to 2.5 by adding orthophosphoric acid. The detection of the combined dosage form was carried out at 320 nm and flow rate was set to 1ml/min. Linearity was obtained in the concentration range of 5 to 25 μg/ml of nitazoxanide and ofloxacin with correlation coefficients of 0.9987 and 0.9995, respectively. The results of the analysis were validated statistically and recovery studies confirmed the accuracy of the proposed method

Magnetic Field Dependence of Entropy And Specific Heat of YBa2Cu3O7-delta Superconductors

The change in thermodynamic quantities (e. g., entropy, specific heat etc.) by the application of magnetic field in the case of the high-T-c superconductor YBCO system is examined phenomenological by the Ginzburg-Landau theory of anisotropic type-II superconductors. An expression for the change in the entropy (Delta S) and change in specific heat (Delta C) in a magnetic field for any general orientation of an applied magnetic field B-a with respect to the crystallographic c-axis is obtained. The observed large reduction of specific heat anomaly just below the superconducting transition and the observed variation of entropy with magnetic field are explained quantitatively

Developing a design process model for the reuse of knowledge

This paper describes the development of a design process model to support knowledge management and design reuse in industry. A sub-system of a vacuum pump in the collaborating company is used as an example in the case study. The design process is modelled using the process modelling technique called Design Roadmap. The design process and knowledge involved were captured in the collaborating company. The design process model also supports design knowledge reuse and design communications through data modelling. The case study describes development of the design process model with real-life industrial information and knowledge, which proves to be a useful knowledge management and design reuse tool for the company to improve their business process and quality of design and manufacturing

A note on magnetization of high temperature superconductors (YBCO, BSCCO) in mixed state

We present a critical study of the temperature and field dependence magnetization of high temperature superconductors (HTSCs). The controversial field dependence of dM/dInB for YBa(2)Cu(3)O(7) (YBCO) and Bi(2)Sr(2)CaCu(2)O(8) (BSCCO) is discussed using different models. Moreover, for both the systems the magnetization (M(H)) dependence is compared with field (H) dependence. (C) 2011 Elsevier B.V. All rights reserved

Study of magnetic field effect on the specific heat and entropy in DyBa2Cu3O7-x

The change in the specific heat by the application of magnetic field up to 161 for high temperature superconductor system for DyBa2Cu3O7-x by Revaz et al. [23] is examined through the phenomenological Ginzburg-Landau(G-L) theory of anisotropic Type-II superconductors. The observed specific heat anomaly near T-c with magnetic field is explained qualitatively through the expression <Delta C > = (B-a/T-c) t/(1 - t)(alpha Theta(gamma)lambda(2)(m)(0)), which is the anisotropic formulation of the G-L theory in the London limit developed by Kogan and coworkers; relating to the change in specific heat Delta C for the variation of applied magnetic field for different orientations with c-axis. The analysis of this equation explains satisfactorily the specific heat anomaly near T-c and determines the anisotropic ratio gamma as 5.608, which is close to the experimental value 5.3 +/- 0.5given in the paper of Revaz et al. for this system. (C) 2010 Elsevier B.V. All rights reserved