The use of a spectroradiometer to study aerial photographs of ozone-treated soybeans

Abstract

Abstract. A scanning spectroradiometer was used to measure the optical densities of an aerial photograph of an experimental field in which soybeans were growing in response to different concentrations of ozone, an air pollutant. The plants were growing in 3 m diameter, 2.4 m high open-top exposure chambers. Correlation coefficients among the film densities, plant yield and visual estimates of non-green leaf area for the 16 test plots were highly significant (p<001); those with ozone treatment concentrations were significant (p<0-05). The early senescence induced by this form of environmental stress can thus be detected by film density differences, and these differences are well correlated with ground indicators of crop condition.     

Optimization of the Gamma-Gamma MAP filter for SAR image clutters

The Gamma-Gamma Maximum a posteriori filter provides an estimate of the speckle-free radar cross-section when both the radar reflectivity and the speckle distributions are gamma-distributed. In this Letter, it is shown that a factor greater than two in precision can be typically gained in the radar cross-section estimate in the case of natural land Synthetic Aperture Radar (SAR) clutters. This is accomplished by using the normalized logarithmic estimator which is a more accurate index than the coefficient of variation to deduce the local heterogeneity parameter.     

Optimal injection velocity profiling

Recently, manufacturers of thermoplastic injection moulding machines have developed controllers with programmable velocity control. The speed of the ram can typically be varied in as many as ten zones during the injection process to establish a velocity profile. This velocity profile however, is determined by trial and error. Some controller manufacturers have made claims about injection velocity profiling, however, actual experimental data is not available to confirm them. In this paper, some experiments were conducted in order to verify the effectiveness of these claims. The results of these experiments indicate that injection velocity control has little effect on reducing or eliminating the problems for which the claims are made.     

Case-based reasoning assisted explanation of genetic algorithm results

Abstract

This paper describes a system for explaining solutions generated by genetic algorithms (GAs) using tools developed for case-based reasoning (CBR). In addition, this work empirically supports the building block hypothesis (BBH) which states that genetic algorithms work by combining good sub-solutions called building blocks into complete solutions. Since the space of possible building blocks and their combinations is extremely large, solutions found by GAs are often opaque and cannot be easily explained. Ironically, much of the knowledge required to explain such solutions is implicit in the processing done by the GA. Our system extracts and processes historical information from the GA by using knowledge acquisition and analysis tools developed for case-based reasoning. If properly analysed, the resulting knowledge base can be used: to shed light on the nature of the search space; to explain how a solution evolved; to discover its building blocks; and to justify why it works. Such knowledge about the search space can be used to tune the GA in various ways. As well as being a useful explanatory tool for GA researchers, our system serves as an empirical test of the building block hypothesis. The fact that it works so well lends credence to the theory that GAs work by exploiting common genetic building blocks.     

Novel microscopy-based approaches to study the film formation mechanism and associated mechanical response in polymer lattices

In this paper, we present the results from novel microscopy-based approaches aimed at providing further insight into the mechanism of film formation and associated mechanical response in polymer lattices. Firstly, a ‘simple’ methodology, combining the use of variable pressure scanning electron microscopy and a recently introduced enhanced coolstage (–50 to +50°C), was successfully developed and not only used to study dynamic processes, e.g. different stages of latex film formation, but also for high-resolution imaging of ‘freeze-dried’ structures. By using the enhanced freeze-drying capability of the system, it was also possible to preserve the structure and features of the studied system with minimum shrinkage and distortion and in the case of polymer lattices at a desired stage of film formation. Moreover, specimens can then be readily imaged, without the need of conductive coatings and at much lower chamber gas pressures, thus minimizing the beam skirting effects and allowing higher resolutions to be achieved. The second and final part of our study consider the mechanical response of the studied latex dried under different conditions, with the particular emphasis on the effects of drying rate [% relative humidity (RH)]. Atomic force microscopy force distance curve measurements revealed that while the %RH did not have an effect on the structures formed, it did have an effect on the adhesive properties of the studied system. It is strongly believed that the methodologies developed and used here can be applied to other material systems, including biologicals and pharmaceuticals.     

Salting and drying of yellowtail (Trachurus mccullochi Nichols)

Wet salting of low-fat yellowtail ( Trachurus mccullochi Nichols) using three brine solutions (15%, 21% and saturated salt) and drying of salted fish at 35°C and 50% RH, 45°C and 30% RH, or 55°C and 18% RH was carried out and assessments made of salt and moisture contents, water activity ( a_w ), and sensory properties of dried-salted fish. Brine concentration during salting and the drying conditions had a significant effect on the drying rate. Brining in saturated brine gave the most rapid rate of reduction in moisture content and the lowest final moisture content during brining, but produced a slower rate of reduction of moisture and higher final moisture content during drying. Fish brined in saturated salt and dried at 55°C was of lower sensory quality.     

Optimization of Sampling Resources

T his paper reports on an investigation into the efficient routing of sample collection in the Lincoln Division of Anglian Water. Samples have to be collected from more than 600 sample points across three functions and at frequencies ranging from daily to once in two years. The organization of this activity is clearly complex.
As a result of the review carried out using manual methods, the additional 15 000 water samples which are required annually are now being collected with no increase in staff resources. The scale of the effort required for this review prevents it from being repeated except at infrequent intervals; yet without frequent reviews the efficiency of routes is eroded as the required pattern of samples changes. A computer system is therefore being developed, offering the prospect of halting the drift away from efficiency and the speedy evaluation of alternative strategies.     

Portable erythema meter and its application to use in human skin

In this study a compact, hand-held, solid state erythema meter using light emitting diodes is described. This device has been constructed and used to compare with visual assessments of ultraviolet radiation in human subjects. A statistically significant correlation was obtained between erythema index and visual assessment in 24 ultraviolet irradiated subjects. Furthermore, the effects of three aftersun treatments have also been assessed objectively using the meter and subjectively using visual assessments. The ultraviolet-irradiated areas were less red following treatment than the irradiated and untreated areas. The results obtained by the meter were similar to and statistically significant with those obtained by visual assessment.
It is concluded that widespread use of an erythema meter such as that described would greatly improve all cutaneous erythema assessments.