A novel microstrip square-loop dual-mode bandpass filter with simultaneous size reduction and spurious response suppression

In this paper, a new capacitively stepped-impedance resonator(CSIR) is proposed to develop the microstrip square-loop dual-mode bandpass filter. Using this new design, simultaneous size reduction and spurious response suppression for the dual-mode bandpass filter can be achieved. An analytical formulation of this novel resonator is given in order to elucidate the spurious frequencies relocation design. Together with this formulation, a generalized dual-mode bandpass filter model is developed so as to ease the analysis of transmission zero and insertion loss. A prototype filter is designed at 900MHz with 1.5% fractional bandwidth. Significant spurious suppressions up to 33 and 35 dB are measured at 1.8 and at 2.7 GHz, respectively. A circuitry size reduction of 54% is achieved when compared with that of the conventional structure. Moreover, the CSIR allows frequency tuning and, thus, a varactor-tuned filter is designed and a measured tunable center frequency between 1.5-1.62GHz is demonstrated. Utilizing the proposed structure, not only size reduction,as well as spurious response suppression, but also center frequency tuning can be achieved.     

The design of school furniture for Hong Kong schoolchildren. An anthropometric case study

Anthropometric data of Hong Kong schoolchildren have been collected and analysed in order to develop recommendations for the design of chairs and tables for use in Hong Kong Government coeducational schools. The anthropometric data for Hong Kong have been compared with data from a Western population (United Kingdom) and another Asian population (Japan). Five sizes of chair and table combinations have been proposed to accommodate six primary and seven secondary forms (pupils aged from 6 to 18 years). The recommended design dimensions, based on the anthropometric characteristics of the Hong Kong target populations, are discussed in relation to recommendations from previous research in this area.     

Multiple time constant modelling of a printed conducting polymer electrode

Constant phase elements (CPE) are routinely used to describe the frequency response of electrochemical systems. However, this approach is often scientifically unsatisfactory because the physical origin of the phase is unclear. Here we observe CPE-like behaviour in a conducting polymer poly(3,4-ethylenedioxythiophene)/poly(styrene-4-sulfonate) (PEDOT:PSS) film that was inkjet printed onto paper to form a flexible electrochemical double layer capacitor electrode. We show that the response of the electrochemically active film can also be described using a physical model with multiple parallel finite RC (resistor–capacitor) transmission lines whose lengths and time constants are determined by the distribution of the measured film thickness. The modeled volumetric capacitance and ionic conductivity match those determined experimentally, suggesting that the physical origin of the constant phase response is a distribution of mass transport limited time constants.     

Evolutionary Computing on Consumer Graphics Hardware

We propose implementing a parallel EA on consumer graphics cards, which we can find in many PCs. This lets more people use our parallel algorithm to solve large-scale, real-world problems such as data mining. Parallel evolutionary algorithms run on consumer-grade graphics hardware achieve better execution times than ordinary evolutionary algorithms and offer greater accessibility than those run on high-performance computers     

Experiments for first year engineering students using tin-bismuth alloys

Introductory courses, whether at the freshman or junior level, are frequently based on the paradigm that processing affects structure, which affects properties, which, in turn, determine performance, and is the basis for design. Once this is understood by the students, it is possible to have them make design decisions based on experimental data and have them identify alternative materials using the paradigm. This paper describes a series of experiments and demonstrations that can be incorporated into an introductory materials course to help students appreciate how processing changes structure, which leads to a change in properties.     

Opening Up the Future of Open Source: From Open Innovation to the Internet of Things for the Built Environment

The architecture, engineering and construction industry is increasingly operating within the merging of physical and digital that defines our era of connectivity. Meanwhile, new semi-open-source platforms such as WikiHouse and Resilient Modular Systems, together with the prospect of traditional supply chains being replaced by localised digital manufacturing, are challenging notions of design ownership. Guest-Editor Wendy W Fok considers what questions designers should be asking themselves in this climate