VHF Boundary Layer Radar and RASS

This thesis describes the refinements, modifications and additions to a prototype Very High Frequency (VHF) Boundary Layer (BL) Spaced Antenna (SA) radar initially installed at the University of Adelaide's Buckland Park field site in 1997. Previous radar observations of the lowest few kilometres of the atmosphere, in particular the Atmospheric Boundary Layer, have used Ultra-High Frequency (UHF) radars. Unlike VHF radars, UHF radars are extremely sensitive to hydro-meteors and have difficulty in distinguishing clear-air echoes from precipitation returns. The advantages and requirements of using a VHF radar to observe the lowest heights is discussed in conjunction with some of the limitations. The successful operation of the system over long periods has enabled in-depth investigation of the performance of the system in a variety of conditions and locations. Observations were made from as low as 300m and as high as 8 km, dependent upon conditions. Comparisons between the radar and alternative wind measuring devices were carried out and examined. The antenna system of the radar is a critical component which was analysed in depth and subsequently re-designed. Through the use of numerical models and mea- surements, evaluation of different designs was accomplished. Further calibration of the remaining components of the full system has enabled estimations of the absolute received power. Additional parameters which can be derived with a calibrated radar were compared with values obtained by other authors, giving favourable results. Full Correlation Analysis (FCA) is the predominant technique used in this work. A brief discussion of the background theory and parameters which can be measured is described. A simple one-dimensional model was developed and combined with a 'radar backscatter model' to investigate potential sources of errors in the parameters determined using FCA with the VHF Boundary Layer Radar. In particular, underes- timations in the wind velocity were examined. The integration of a Radio Acoustic Sounding System (RASS) to obtain tempera- ture profiles is discussed. The theory of RASS measurements including the limitations and considerations which are required for the VHF BL radar are given. The difficulties encountered trying to implement such a system and the subsequent success using a Stratospheric Tropospheric (ST) Profiler in place of the BL radar is presented. Taken as a whole this thesis shows the success of the VHF BL to obtain mea- surements from as low as 300m. The validation of this prototype radar provides an alternative and, in certain situations, a superior device with which to study the lower troposphere.Thesis (Ph.D.)--University of Adelaide, Department of Physics and Mathematical Physics, 2001

Bending creep of corrugated fibreboard in cycling relative humidity : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Agricultural Engineering at Massey University

Packaging of fresh fruit for export is a major use for corrugated fibreboard manufactured in New Zealand. However the cold and humid conditions used to preserve fruit quality are particularly detrimental to the strength of corrugated packaging. The main objective of this study was to develop a method to measure the performance of corrugated fibreboard in high and cycling relative humidity environments. This method was then used to compare the performance of three corrugated fibre-boards 1 For commercial reasons these will be referred to as 'CB1', 'CB2'and 'CB3' The creep performance of corrugated fibreboard was measured by subjecting samples to four point bending stress under controlled cyclic relative humidity conditions using a computer controlled testing apparatus. A mathematical model by Urbanik (1995) and an empirical exponential model were reviewed before selecting a three term model developed by Pecht (1985) to describe the deflection of the corrugated board. Cyclic relative humidity accelerated the rate of creep compared to a static high humidity environment. The rate of creep in the machine direction was found to be considerably lower than that in the cross machine direction. It was also found that increasing the peak relative humidity from 80% to 90% RH dramatically changed the deflection response. This provides a solution to conflicting data in the literature on relative humidity cycling effects. Isochronous deflection curves were used to compare the creep performance of the corrugated fibreboard samples in an environment cycling between 50% and 90% RH. Corrugated fibreboard sample CB1 had a slightly lower creep stiffness than corrugated boards CB2 (p=0.0580, n=8) and CB3 (p=0.0398, n=8). However a greater number of tests would be required on a wider range of samples to conclusively determine if there were differences in board performance

Are Houses Too Big or In the Wrong Place? Tax Benefits to Housing and Inefficiencies in Location and Consumption

Tax benefits to owner-occupied housing provide incentives to consume housing, offsetting weaker disincentives of the property tax. These benefits also help counter the penalty federal taxes impose on households who work in productive high-wage areas, but reinforce incentives to consume local amenities. We simulate the effects of these benefits in a parameterized model, and determine the consequences of various tax reforms. Reductions in housing tax benefits generally increase efficiency in consumption, but reduce efficiency in location decisions, unless they are accompanied by tax rate reductions. The most efficient policy would eliminate most tax benefits to housing and index taxes to local wage levels

Tusnady's inequality revisited

Tusnady's inequality is the key ingredient in the KMT/Hungarian coupling of the empirical distribution function with a Brownian bridge. We present an elementary proof of a result that sharpens the Tusnady inequality, modulo constants. Our method uses the beta integral representation of Binomial tails, simple Taylor expansion and some novel bounds for the ratios of normal tail probabilities.Comment: Published at http://dx.doi.org/10.1214/009053604000000733 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org