Development of piezoelectric fans for flapping wing application

A piezoelectric fan (piezofan) which couples a piezoelectric unimorph to an attached flexible blade is able to produce a large deflection especially at resonance. The fundamental resonant frequencies (f_r) of the piezofan structures have been calculated by an analytical method and finite element modelling, and these were compared with experimental measurements. Good agreements have been obtained between them. The free tip deflection at quasi-static operation or/and the vibration amplitude at dynamic operation (A) of the piezofans have been experimentally measured. We introduce f_r × A as an optimization criterion for piezofans. Optimization according to this criterion has been carried out for some piezofan configurations, such as the length and the location of the piezo patch, as well as the thickness ratio between the elastic and piezoelectric layers among a few available variations. Results show this optimization approach to be promising when compared to previously defined piezofan performance parameters such as the energy transmission coefficient and electromechanical coupling coefficient.     

Numerical modelling of production from the Poihipi dry steam zone: Wairakei geothermal system,New Zealand

The Poihipi power station utilizes dry steam from a shallow zone near the margin of the Wairakei geothermal reservoir. The station has been in operation for several years, with daily variations in the fluid production rate following variations in time-of-day pricing of electricity. The corresponding varying pressure history provides a good database for testing models of the geothermal reservoir.     

World Wide Web enabled operational support systems — a testing perspective

BT uses many operational support systems (OSS) in the course of its business. The major customer service system (MCSS) is one such OSS used for electronic dialogue with major customers. The client/server approach currently used is being superseded with a call for a World Wide Web (WWW) interface and adoption of a mid-tier server/thin-client approach. This paper examines how practical verification, validation and test (VV&T) techniques can be applied to such systems. Three WWW technologies are examined here as researched and implemented within the MCSS Bali project. The three technologies are Common Gateway Interface (CGI), Java and Citrix WinFrame.     

Access to dental care--experiences of men with HIV infection in the United Kingdom

A piloted self-complete questionnaire enquiring about dental experiences was administered to a consecutive sample of men with asymptomatic HIV infection attending a dedicated clinic in London. Forty-seven men completed questionnaires. Despite a high level of dental attendance before diagnosis of HIV infection, 60% of the men had not visited a general dental practitioner since diagnosis. Nineteen men had visited a dentist since diagnosis; 15 had been refused or deterred by members of the dental team and 5 had attended without disclosing their HIV status. These data indicate that despite professional guidance to dentists, the perceptions of dentists held by people with HIV and the behaviours of dentists acts as barriers to care. Dedicated dental clinics act as an important safety-net for people with HIV infection.     

Method development and analysis of retail foods and beverages for carotenoid food colouring materials E160a(ii) and E160e.

An analytical method using high-performance liquid chromatography with photodiode array detection was developed and applied to the determination of the permitted food colour additives beta-carotene(E160a(ii)) and beta-apo-8'-carotenal (E160e) in foods and beverages. The scope of previously reported methods has been broadened to cover a wide range of retail foods and enzymatic hydrolysis has been used in place of saponification for high-fat samples. Quantitative results (greater then 0.1 mg kg(-1)) are given for the major colour principals trans-beta-apo-8'-carotenal and trans-beta-carotene. Semiquantitative results are given for the various cis-isomers of each colorant for which authentic reference standards were not available. The method has been used successfully for the analysis of a wide range of foodstuffs with differing fat content without the need for saponification, except for moderate- to high-fat foodstuffs containing significant levels of emulsifiers, for which it was limited. The results suggest that beta-apo-8'-carotenal (E160e) does not have widespread use in the UK. None of the samples exhibited a total beta-carotene content greater than 20 mg kg(-1) and none of the high-fat samples and only one of the 17 low-fat/beverage samples contained total beta-carotene at levels less than 0.1 mg kg(-1). The total beta-carotene contents of the low-fat/beverage samples ranged from 0.4 +/- 0.03 to 8.4 i 0.71 mg kg(-1), and the total beta-carotene contents of the high-fat samples ranged from 0.1 +/- 0.01 (jelly confectionery) to 18.5 +/- 0.98 mg kg(-1) (processed cheese).