Quality control on the site

Quality standards in site construction often leave much to be desired. To discover more about the factors which in practice affect the standards achieved, the UK Building Research Establishment made a special study of 27 sites. It revealed how personalities are sometimes more important than apparent functions.     

Characterization of flicker noise in GaAs MESFET's for oscillatorapplications

GaAs MESFET oscillators commonly exhibit increased close-to-carrier noise, which is often attributed to upconversion of flicker noise from the MESFET. To establish and quantify this effect, this paper presents an experimental system that allows the simultaneous measurement of the flicker noise on the gate and drain terminals of a GaAs-MESFET, and of the noise imposed on an RF carrier when amplified by the MESFET. The cross correlations between these parameters can thus be determined; an analytical method is shown for extracting the levels of the effective sources of flicker noise from the results, and the manner in which these affect the RF carrier. In the tests performed, it was often found that the close-to-carrier noise was related directly to the low-frequency flicker noise     

The Prediction of Geometric Distortions in Airborne Synthetic Aperture Radar Imagery from Autofocus Measurements

The synthetic aperture radar (SAR) is an imaging system that achieves high azimuthal resolution by tracking individual point scatterers using their phase histories, with the expected phase history of a particular point scatterer being derived from the assumed motion of the airborne SAR platform. Normally, it is assumed that the platform travels along a straight line path and that the radar pulses are emitted at equal spatial intervals. However, the aircraft carrying the SAR will be susceptible to extraneous across tracl motions and errors in the pulse spacing also may occur. These errors manifest themselves. as two forms of image degradation in the final image. Firstly, the image will be defocused due to an error in the expected quadratic phase history, and secondly, the image will contain geometric distortions due to an error in the linear phase history. An autofocus technique can be used to focus the image and produce a measure of the quadratic phase error that in turn can be used to estimate the geometric distortions that will be present in the final image. These distortions can be independently measured by direct comparison with a map of the imaged area. This paper describes the application of these methods to some real SAR data and discusses the results of the comparison of the measurements of autofocus and geometric distortions in terms of both the likely platform motions present and the viability of predicting geometric distortion using the autofocus measurements.     

Les pompes de chaleur manquent encore d'intérêt du point de vue coût

Lors d'une réunion ayant eu lieu il y a quelques mois, un sous-groupe technique de la commission de travail CIB W 67 sur la conservation de l'énergie a passé en revue les possibilités et les problémes des pompes de chaleur. La réunion a confirmé que les possibilités des pompes de chaleur sont considérables quant à la conservation de l'énergie et tous les pays sont tellement intéressés que le besoin d'une collaboration dans les recherches s'est intensifié.     

Positive ion AMS with a single-stage accelerator and an RF-plasma ion source at SUERC

The new single-stage accelerator mass spectrometer at SUERC can also accept positive ions. Potential benefits of positive ion measurement with suitable ion sources are more convenient sample form, smaller sample size, a variety of available charge states and maybe new applications. We have begun with oxygen isotope analyses to demonstrate destruction of interfering molecules.     

Development and Assessment of a Small‐Scale Wort Filtration Test for the Prediction of Beer Filtration Efficiency

A Small‐scale Wort rapid Filtration Test (SWIFT) that predicts beer filtration efficiency has been developed. The test is simple, cost effective and correlates with existing beer filtration tests such as beer V_max membrane (Esser test) and diatomaceous earth (Walton filter) tests. SWIFT has an advantage over existing beer filtration tests as it can be easily incorporated into barley quality laboratories utilising excess wort from extract analyses, thus negating the need for additional sample preparation or to ferment and age beer. Furthermore, the test does not rely on expensive equipment or specially trained laboratory technicians. SWIFT, which may also be used to evaluate degassed beer, is a syringe test that utilises a 13 mm diameter 0.45 μm membrane and is negatively influenced by wort viscosity (P<0.05). It is envisaged that SWIFT may be applied by barley breeding programs for the evaluation of progeny lines to provide a better prediction of beer filtration performance than total wort β‐glucan measurements. In addition, maltsters and brewers could use SWIFT to assess malt samples, and provide early warning of potential beer filtration problems during the brewing process.     

Relation of direct assessment of cardiac autonomic function with metaiodobenzylguanidine imaging to heart rate variability in diabetes mellitus

We investigated the sequential change in the hypervariable region 1 (HVR 1) of hepatitis C virus (HCV) E2/NS1 gene in an infant. He was transfused with 160 mL of blood containing the HCV (0.7 Meq/mL) on the 6th d after birth and subsequently developed chronic viremia. At 16 mo, the HVR1 amino acid sequences of HCV observed in the infant's sera were very similar to those from the donor (his maternal grandfather) on the day of transfusion. However, highly variable amino acid sequences of HVR1 were observed throughout infancy. These results demonstrate that an adaptive response of HCV to evade host immunity seems to occur, as in adult cases, even in early infancy when the ability to produce humoral immunoglobulin is thought to be low.