A Spectral-Knowledge-Based Approach for Urban Land-Cover Discrmination

A prototype expert system was developed to demonstrate the feasibility of classifying multispectral remotely sensed data on the basis of spectral knowledge. The spectral expert was developed and tested with Thematic Mapper Simulator (TMS) data having eight spectral bands and a spatial resolution of 5 m. A knowledge base was devloped that describes the target categories in terms of characteristic spectral relationships. The knowledge base was developed under the following assumptions: the data are calibrated to ground reflectance, the area is well illuminated, the pixels are dominated by a single category, and the target categories can be recognized without the use of spatial knowledge. Classification decisions are made on the basis of convergent evidence as derived from applying the spectral rules to a multiple spatial resolution representation of the image. The spectral expert achieved an accuracy of 80-percent correct or higher in recognizing 11 spectral categories in TMS data for the Washington, DC, area. Classification performance can be expected to decrease for data that do not satisfy the above assumptions as illustrated by the 63-percent accuracy for 30-m resolution Thematic Mapper data.     

Missed curable carcinoma of the pancreas presenting as chronic pancreatitis

We present a case of pancreatic malignancy which presented as chronic pancreatitis. The diagnostic difficulties are discussed. We recommend that when there is any doubt about a diagnosis of chronic pancreatitis with a pancreatic mass, then early resection is appropriate.     

Familial paraganglioma

Non-secreting paragangliomas are rare tumours usually present in the head and neck. We describe an unusual case of familial paraganglioma with cranial nerve palsies. After exhaustive investigation, a vagal paraganglioma, was found and excised. The positive family history of paraganglioma was of significance, although this was only present in one of five generations. The diagnosis and management of non-secreting paragangliomas is discussed.     

A comparison of wesson loss and cup refining loss analyses of crude cottonseed and soybean oils

Wesson loss and cup refining loss were determined on 100 samples of crude cottonseed and soybean oils produced in different sections of the country. The Wesson method gave more reproducible results than the cup method. Wesson loss results were found to be closely indicative of the total neutral oil content of crude oils. The average ratio of cup loss to Wesson loss was 2.3 for crude cottonseed oil and 1.7 for crude soybean oil. The ratio varied considerably for individual crude oils of a given kind, or type within each kind, or a local producing section. Therefore, no real useful correlation between the results of the two methods was found to exist.     

Factors that affect the impact sensitiveness of ammonium nitrate - fuel oil (ANFO) explosives containing aluminium

Abstract

We report the results of a study to investigate the effect of aluminium on the impact sensitiveness of a range of Ammonium Nitrate-Fuel Oil (ANFO) mixtures.

The data obtained indicate that the impact sensitiveness of these mixtures depends on the quantity and type of aluminium, and on the ratio of ammonium nitrate to fuel oil. The magnitude of the dependences is relatively small, however, and all the aluminium-ANFO mixtures examined can be classed as “comparatively insensitive”. We have also shown that the sensitiveness of such mixtures to impact can increase if they contain small quantities of rust or grit as a contaminant.     

The application of neural networks to the assessment of impact testing on explosives

Abstract

The BAM Fallhammer test is one of the most widely used impact tests, but the results of the test rely on the subjective assessments of the test operator using the senses of hearing, smell and sight. The paper describes an investigation into the suitability of using a neural network for determining the outcome of BAM Fallhammer tests. The network utilises digital data from instrumentation installed around the BAM apparatus, including a microphone and a gas sensor.

Selected examples are given to show that neural networks have the potential to distinguish between the test results of ‘no reaction’, ‘decomposition’, and ‘explosion’ for propellants, plastic and high explosives. The technique removes the possible operator dependence of assessments and the study in general may also lead to clarification of the categories involved in defining the test outcome.     

Multiple paths to nanocrystalline high silica beta zeolite

Several principles from nanozeolite synthesis lore were investigated in order to prepare discrete pure silica nanocrystalline BEA zeolite. It was discovered that lowering reaction temperature to 100 °C results in a significant reduction in nano-BEA crystal size, that lowering synthesis mixture water content to the lowest possible level for a ‘pourable’ gel provides nano-BEA crystals, that tetraethylorthosilicate (TEOS) more consistently provides smaller crystals than fumed silica as a raw material, that increasing the level of structure-directing agent resulted in more discrete and smaller crystals (25–30 nm), and that ‘surfactant’ addition could generate even smaller nano-BEA crystals or nanocrystalline domains, but mild to severe aggregation was still a problem. Nearly pure silica nanocrystalline BEA zeolites were prepared from Al-containing products by a calcination followed by acid extraction procedure. The calcination step is critical for more complete Al removal. Defects generated by acid extraction could be healed by treatment of resultant powder with a hexamethyldisilazane (HMDS). Another key finding was that Al-containing synthesis mixtures could provide nanocrystalline BEA zeolite with 4,4′-trimethylenebis(N-methyl, N-benzyl-piperidinium) dihydroxide (TMP(OH)₂) as organic structure-directing agent. Interestingly, adjusting synthesis parameters in TMP and Al-containing synthesis mixtures provided some differences to pure Si BEA products. For example, stirring or lowering reaction temperature did not decrease crystal size, but did shorten crystallization time. The smallest crystals from TMP-based, Al-containing reaction mixtures were prepared when a freeze–dried colloidal silica was utilized as silica source.     

Modulation of firefly luciferase bioluminescence at bioelectrochemical interfaces

This paper describes a method by which the activity of an immobilized enzyme can be modulated electrochemically at an electrode. The particular example studied, involving the enzyme firefly luciferase being immobilized in a gelatin film of thickness <1 μm, provides a useful model system since changes in the catalytic activity can be measured instantaneously through the natural bioluminescent emission. Using this biointerfacial arrangement, we have been able to demonstrate the reversible switching off and on of the enzyme's activity. Through a series of mechanistic studies, we have been able to determine that the bioluminescence response is modulated (on long time scales) as a consequence of the electrochemical depletion of protons at the electrode interface resulting in a local increase in pH.     

A comparative study of Desktop, Fishtank, and Cave systems for the exploration of volume rendered confocal data sets

We present a participant study that compares biological exploration tasks using volume renderings of laser confocal microscopy data across three environments which vary in level of immersion. For the tasks, data, and visualization approach used in our study, we found that subjects qualitatively preferred and quantitatively performed better in environments with greater levels of immersion. Subjects performed real-world biological data analysis tasks that emphasized understanding spatial relationships including characterizing the general features in a volume, identifying co-located features, and reporting geometric relationships such as whether clusters of cells were coplanar. After analyzing data in each environment, subjects were asked to choose which environment they wanted to analyze additional data sets in--subjects uniformly selected the Cave environment.