CO oxidation kinetics over a nanostructured Cu0.1Ce0.9O2−y catalyst: a CO/O2 concentration cycling study

Topics in Catalysis - Feed composition cycling as a transient kinetic technique provides detailed information about elementary steps in CO oxidation over a nanostructured Cu0.1Ce0.9O2?y...     

Temperature Stable Dielectric Behavior of Sol–Gel Derived Compositionally Graded SrTiO3/Na0.5Bi0.5TiO3/SrTiO3 Thin Films

Polycrystalline sol–gel‐derived SrTiO₃/Na_0.5Bi_0.5TiO₃/SrTiO₃ (ST/NBT/ST) thin films were designed to achieve the electrical isolation of the NBT, and to mediate the temperature dependency of the dielectric properties. Proper thermal annealing of particulate phase enabled us to achieve compositionally graded elemental profiles between individual ST and NBT layers. The dielectric and ferroelectric properties were investigated with respect to the electrical behavior of the monophasic ST and NBT thin films. The dielectric characteristics of the multilayer thin film were marked by a temperature stable behavior (temperature coefficient of dielectric constant of 780 ppm/°C) in the measured ?50°C to 200°C range, frequency‐independent response at room temperature and improved dielectric loss characteristics compared with the NBT; however, on the expense of decreased permittivity and a reduced ferroelectric stability. Nevertheless, stable dielectric properties were achieved and properties of multilayer may well be exploited in functional devices that demand insensitive operation over wide temperature and frequency ranges.     

Concurrent engineering in small companies

In 1991, attainment of independence in Slovenia caused a drastic decrease in the domestic market for Slovenian companies. The companies which did not adapt to the new market conditions were destined for ruin. In this time several smaller companies were established which could adapt to new market conditions more easily. When these companies entered the world market they encountered several difficulties such as excessive flow times for development of new products. After a survey of available literature had been made it was found that those problems could be solved by transforming sequential engineering to concurrent engineering. The article presents the principles of sequential and concurrent product development processes. The market forces small Slovenian companies to a transition from sequential to concurrent engineering and as team work is the basic element of the concurrent engineering, special attention has been paid to workgroups forming in the loops of concurrent product development process in small companies.A survey of published works in the field of planning teams in big companies has revealed that a three-level team structure is recommended in big companies. Analysis of the three-level structure has led us to the conclusion that a two-level team structure and matrix organisation should be preferred in small companies.Presented are the results of planning a two-level team structure and matrix organisation of a small Slovenian company which produces mini-loaders.     

How to reduce new product development time

When entering the global market the companies encounter several difficulties, the most important one being excessive time for new product development. This problem can be solved by transition from sequential engineering to concurrent engineering, (Concurrent Engineering Fundamentals, Integrated Product and Process Organization, Vol. I, Prentice Hall PTR, New Jersey, 1996; Concurr. Eng. Res. Appl. 9 (2001) 191).The article presents the principle of concurrent product development process. The market forces small- and medium-size enterprises (SMEs) to a transition from sequential to concurrent engineering and as team work is the basic element of the concurrent engineering, special attention is being paid to team and workgroup forming in the loops of concurrent product development process in an SME. The article does not deal with communication issues within a team and among teams.A survey of published works in the field of designing teams in big companies has revealed that in big companies a three-level team structure is recommended, as well as a workgroup, consisting of four basic teams. Analysis of the three-level team structure has led us to the conclusion that in SMEs a two-level team structure and a workgroup consisting of two basic teams should be preferred.The results of designing a two-level team structure and the project of transition to concurrent development of mini-loader are presented. Time and cost analysis results prove the justification of transition from sequential to concurrent product development.     

Realistic lead time scheduling of operations of orders

The aim of the lead time scheduling of operations of orders is to define the starting and completion times of the planned operations involving either single-stage (parts) or multi-stage (subassembly parts) orders based on a previously determined time of starting and completion of a particular order.In this article, the role of the lead time scheduling of operations of orders within the whole production planning and control process is presented. Computer-aided procedures, needed to determine the real mean lead time of operations, and the real lead time scheduling of operations of orders are proposed. The results of determining mean lead times of operations, and the lead time scheduling of operations of orders, that was carried out in a company which produces equipment for civil engineering, are reported.     

The application of thick-film technology in C-MEMS

Laminated 3D structures made using low-temperature co-fired ceramic (LTCC) technology are practical for ceramic micro-electro-mechanical systems (C-MEMS). The sensors for mechanical quantities, and/or actuators, are fundamental parts of MEMS. Thick-film resistors can be used to sense the mechanical deformations, and thick-film piezoelectric materials can be used as electro-mechanical transducers in a C-MEMS structure. The integration of these thick-film materials on LTCC substrates is in some cases difficult to realise due to interactions with the rather glassy LTCC substrates. The subject of our work is an investigation of thick-film materials for electro-mechanical transducers (sensors and actuators) and their compatibility with LTCC substrates. Resistors made with commercial thick-film resistor materials for use as sensors on LTCC substrates have been investigated and evaluated. Ferroelectric ceramic materials based on solid solutions of lead zirconate titanate (PZT) with low firing temperatures around 850°C were developed for thick-film technology and evaluated on LTCC substrates.