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This study has investigated the influence of microstructure on the corrosion properties of AA7108 T6 aluminium alloy extrusions. Additionally, through the analysis of AA7108 alloy, the using of highresolution electron microscopy allowed the characterising of microstructure evolution during corrosion process from microscale to nanoscale. This provides previously unseen details of trenching corrosion, intergranular corrosion and crystallographic corrosion. Based on these details, the relevant corrosion mechanisms are proposed. Besides the general characterisation of intermetallic phases and grain structure of AA7108 alloy, the local microstructural variation related to Fe-containing constituent intermetallic particles is characterised. Non-uniform local plastic deformation and precipitate free zones (PFZs) are observed in the regions surrounding the particles; an aluminium oxide film and an Fe-rich layer beneath the oxide film are also observed on the Fe-containing particle surface. Further, discontinuity in the distribution of η'/η (MgZn₂) phase precipitates and variation in the width of PFZs are characterised at dislocations, sub-grain boundaries and grain boundaries. It is revealed that the size and the local discontinuity of η'/η (MgZn₂) phase, as well as the width of PFZs show the increase tendency with the degree of misorientation increasing. Corrosion test in neutral NaCl solution shows that trenching corrosion around Fe-containing particles is the primary corrosion phenomenon of AA7108 alloy. Up to even 5 hours exposure to the testing solution, intergranular corrosion or other types of severe localised corrosion are rarely observed. In contrast, corrosion test in NaCl solution acidified to pH 3.2 shows that intergranular corrosion and crystallographic corrosion are the main corrosion phenomena of AA7108 alloy. During trenching corrosion, Fe-containing particles as the net cathodes are not completely under cathodic protection. The corrosion of Fe-containing particles occurs as soon as the start of the immersion test, resulting in Fe-rich corrosion product on particle surface. As the net anode, alloy matrix dissolution leads to porous oxide film growth on the corroded Al matrix surface. The porous oxide film is perpendicular to the corroded matrix surface. The results suggest that these two phenomena are related to the local alkalisation due to the oxygen reduction reaction on particle surface. The corrosion morphology is consistent with the local alkalinity distribution. The mechanism of trenching corrosion induced by Fe-containing particles is proposed. Further, during the early stage, trenching corrosion might not be uniform, which is due to the non-uniformity of the local alkalinisation. The corrosion potential difference, the surface defects or the localised plastic deformation do not show significant influence on the non-uniformity of trenching corrosion. The test and associated characterisation also suggest that Clions do not play a significant role in trenching corrosion. In acidic NaCl solution, intergranular corrosion is initiated from the surface cavities introduced by the preferential dissolution of MgZn2 precipitate. Then, intergranular corrosion propagates via a combination of two factors: the driving force related to crystallographic dissolution and the driving force related to dissolution along the grain boundary interface. Crystallographic corrosion of grain interior propagates develops the typical half-cube corrosion morphology. The regions, with a high population of Al3Zr dispersoids, are resistant to crystallographic corrosion.

The Sámi’s past activities have been documented historically from a European perspective, and more recently from an anthropological viewpoint, giving a generalised observation of the Sámi, during the study period of AD200-AD1800, as semi-nomadic hunter gatherers, with several theories suggesting that interaction with Europeans, through trade, led to the adoption of European activities by certain groups of the Sámi (Eiermann, 1923; Paine, 1957; Manker and Vorren, 1962; Bratrein, 1981; Mathiesen et al, 1981; Meriot, 1984). However, there is almost no information on the impact the Sámi had on the landscape, either before or after any adoption of European activities, and none investigating what cultural footprint or indicators would remain from Sámi or European occupation and/or activity within the typically podzolic soils of Northern Sweden. Consequently the thesis aims to contribute to the gap in knowledge through the formation of a podzol model identifying the links between anthropogenic activity and the alteration of podzol soils, and through the creation of soils based models which identify the cultural indicators associated with both Sámi and European activity; formed from the identification of cultural indicators retained within known Sámi and European sites. The methods used to obtain the information needed to achieve this were the pH and magnetic susceptibility from bulk soil samples and micromorphological and chemical analysis of thin section slides through the use of standard microscopy and X-ray fluorescence from a scanning electron microscope. The analysis revealed that the Sámi had an extremely low impact on the landscape, leaving hard to detect cultural indicators related to reindeer herding in the form of reindeer faecal material with corresponding phosphorous peaks in the thin section slides. The European footprint however, was markedly different and very visible even within the acidic soil environment. The European indicators were cultivation based and included phosphorous and aluminium peaks as well as a deepened, highly homogenised plaggen style anthropogenic topsoil rich in ‘added’ materials. An abandoned European site which visibly and chemically shows the formation of a secondary albic horizon within the anthropogenic topsoil also provides an insight into the delicate balance of cultivated soil in northern Sweden, whilst reinforcing the outputs identified in the podzol model. Due to the almost invisible Sámi footprint on the landscape, areas of overlap were impossible to identify however, there was no evidence of the adoption of European cultivation activities at any of the Sámi sites investigated. The only known area of interaction between the two cultures was an official market place which had been a Sámi winter settlement prior to its use as a market site. This site showed none of the reindeer based Sámi indicators or the cultivation based European indicators, but did contain pottery fragments which could be linked to trade or occupation. Overall, the thesis reinforces the low impact expected of the semi-nomadic Sámi and sheds light on the underlying podzolic processes influencing the anthropogenically modified soils of Northern Sweden. The podzol model is reinforced by several findings throughout the thesis and the soils based cultural indicator models for both Sámi and European activity have been successfully tested against independent entomological and palynological data and therefore provide reliable reference material for future studies.

In recent years, nanoparticles have emerged as an intriguing tool in the field of agriculture, showing capabilities to increase performance and efficiency in several areas throughout the process of crop production. For many applications, their beneficial abilities depend on their resistance to detachment. However, this quality can have detrimental effects to human health once produce has left the farm. Therefore, it is important to accurately quantify attachment and detachment, as well as provide insight into what factors influence these qualities. Nanoparticles of different structure and concentration were applied to organic surfaces in 5 µL drops. A rinsing procedure was then developed to simulate a process by which produce is washed before consumption. Samples were then imaged with a scanning electron microscope (SEM) using both backscatter and secondary electron modes. Using the SEM’s backscatter electron detection, an image thresholding program was developed. Images were broken into pixels and segmented by brightness intensity. A threshold was then calculated from the derivative of reverse-cumulative brightness intensity frequency, from which pixels were binned into nanoparticles and non-nanoparticles. Images were taken of both rinsed and unrinsed surfaces, allowing a visual comparison and computerized quantification of detachment rates. At higher nanoparticle concentrations, significant detachment took place for nanoparticles studied. No decrease in particle frequency could be observed at the low end of concentrations. Addition of extracellular polymeric substances (EPS) as well as variations in pH had no observed significant effect on detachment.

Chaetodactylidae mites are kleptoparasites of solitary bees in the families Megachilidae and Apidea. Chaetodactylus krombeini is a North American pest most often associated with Osmia lignaria. Chaetodactylidae mites can cause up to 50% losses of bee offspring in nests and cause adult bees to develop into less efficient pollinators. Managed Osmia beekeepers need control methods for these parasites, however there is little known about C. krombeini life history making it difficult to efficiently decrease their harmful effects. Mite host preference is unclear as there are contradictory reports of male and female bees being the preferred host of the phoretic deutonymph. Host sex preference was examined by recording mite distribution within host nests. Mite distribution determined if phoretic deutonymphs dropped off hosts in female cells (back of nest) or male cells (middle and near nest entrance) during nest building. This experiment yielded low mite numbers within each nest, though mites were found in the back of nests regardless of host sex, possibly indicating mites have a positional preference rather than a host sex preference. Heteromorphic deutonymphs of C. krombeini are hypothesized to be exclusively female. This hypothesis leads to additional hypotheses of C. krombeini requiring arrhenotokous parthenogenesis and oedipal mating to found mite populations. Sex determination assays of the heteromorphic deutonymphs were conducted in 2-week periods for each mite. Inert and phoretic deutonymphs were individually placed in microcentrifuge tubes with a pollen provision then sexed when mites developed into adults. Phoretic deutonymphs were allowed to overwinter with and without a bee host. Males and females developed from both morphs of the heteromorphic deutonymph. Male and female dispersal prior to mating may indicate sexual reproduction is required for this species. Scanning electron microscopy was used to examine C. krombeini morphology to gain insight into life history traits. Specimens of C. krombeini were prepared with ethanol and hexamethyldisilazane. Images will be useful to compare the morphology of C. krombeini to mites with known life history traits and to other species that are indistinguishable from C. krombeini. These experiments contribute to the knowledge of C. krombeini, helping future control efforts of this pest.

Abstract: The lower Albian (Cretaceous) Falher F submember of the Spirit River Formation in the Wapiti area consists of four stacked coarsening-upward successions of northward prograding strandplain to wave-dominated delta deposits. Routine core analyses revealed that four facies associations can be identified within the study interval, which reflect a shoaling-upward trend from storm-dominated shoreface, wave-dominated shoreface, brackish embayment, to coastal plain settings deposited adjacent to wave-dominated delta. Integration with geophysical well logs enabled the construction of the local paleogeographic evolution of various depositional environments within each parasequence in the study area, which can be explained using a sequence stratigraphic model.The complexity of the microscale reservoir characteristics within the tight sandstone intervals is largely due to the abundance of chert clasts and grains as well as interstitial allogenic and authigenic components, which contribute to the challenges related to the sandstone drillability and hydrocarbon storability, respectively. In this study, a petrographic approach was primarily employed to understand the relative distribution of the chert content and the diagenetic events within the tight sandstone units. The resulting reservoir characteristics can then be explained in reference to the palaeogeographic framework.This study shows that changes in the chert-controlled drillability of the Falher F tight sandstone correspond to variations in depositional energy and settings. In terms of hydrocarbon storability, secondary porosities such as dissolution, microfractures, and other micropores that followed the pore-occluding diagenetic events are primarily responsible for retaining the porosity of the unit.

Electron microscopes have the capability to examine specimens at much finer detail than a traditional light microscope. Higher electron beam voltages correspond to higher resolution, but some specimens are sensitive to beam damage and charging at high voltages. In the scanning electron microscope (SEM), low voltage imaging is beneficial for viewing biological, electronic, and other beam-sensitive specimens. However, image quality suffers at low voltage from reduced resolution, lower signal-to-noise, and increased visibility of beam-induced contamination. Most solutions for improving low voltage SEM imaging require specialty hardware, which can be costly or system-specific. Point spread function (PSF) deconvolution for image restoration could provide a software solution that is cost-effective and microscope-independent with the ability to produce image quality improvements comparable to specialty hardware systems. Measuring the PSF (i.e., electron probe) of the SEM has been a notoriously difficult task until now. The goals of this work are to characterize the capabilities and limitations of a novel SEM PSF determination method that uses nanoparticle dispersions to obtain a two-dimensional measurement of the PSF, and to evaluate the utility of the measured PSF for restoration of low voltage SEM images. The presented results are meant to inform prospective and existing users of this technique about its fundamental theory, best operating practices, the expected behavior of output PSFs and image restorations, and factors to be aware of during interpretation of results.

Membrane Distillation (MD) is a separation process driven by the vapour pressure difference established across hydrophobic membrane. In order to combine the advantages of conventional MD configurations, Permeate Gap Membrane Distillation (PGMD) modules were developed. The objectives of this study were to systematically evaluate the performance of several new hollow fibre PGMD modules. This study consisted of four components. First of all, the membrane was systematically characterized. The membrane dimension and morphology were investigated using Scanning Electron Microscope (SEM). The membrane porosity was measured using the wetting method. The membrane hydrophobicity was determined by measuring the contact angles of the inner and outer hollow fiber surfaces. Finally, Liquid Entry Pressure (LEP) was investigated. Based on the membrane characterization, it was confirmed that the employed hollow fibre membrane was suitable for MD application. Next, a single PGMD module was built with 8 gap channels and 1 hollow fibre within each gap channel. This module was operated in different modes (PGMD, DCMD and SGMD) to compare their performance. The results showed that the maximum flux of hollow fiber PGMD was 27% and 1.6% lower than the maximum flux of DCMD and SGMD respectively. This phenomenon was due to the higher coolant velocity for DCMD and applied air flow in the gap channel for SGMD. The mass transfer coefficient was also used as an indicator to compare performance. For PGMD, the mass transfer coefficient increased initially at the lower feed inlet temperature and then decreased when the feed inlet temperature was higher than 60˚C, which could be attributed to the combined effects of transverse vapor flux and temperature non-uniformity of the bulk flow. On the contrary, the global mass transfer coefficients of DCMD and SGMD decreased slightly as a function of feed inlet temperature. Compared to other studies, our results demonstrated that PGMD has the potential to effectively combine the advantages of different conventional MD processes. Afterwards, we have investigated the impacts of different PGMD module designs on water productivity and energy efficiency. The results showed that module with lower hollow fibre packing density or gap channel density had a higher flux and better energy efficiency, while modules with higher hollow fibre packing density or gap channel density exhibited more energy efficient use of the membrane surface area and higher productivity. Additionally, the module with a more conductive cooling plate had a higher flux and lower Specific Thermal Energy Consumption (STEC), which was mainly attributed to the lower thermal resistance of the cooling plate. Due to the nearly stagnant velocities within the gap and coolant channels, the impact of cooling plate material on PGMD performance was greater than that of hollow fibre packing density and gap channel density. The Gain Output Ratio (GOR) obtained for the hollow fibre PGMD module was relatively low compared to other MD studies, however, the PGMD module performance cannot be assessed purely based on GOR. A trade-off exists between GOR and flux for MD modules, and the flux obtained from our hollow fibre PGMD module was relatively high. Finally, a set of mathematical models were developed to simulate the mass and heat transfers phenomenon in hollow fibre PGMD process. The validated model was employed to evaluate the impacts of important MD design parameters on module performance. The modelling results showed that coolant velocity and coolant temperature had less impact on flux compared to those of DCMD, because the coolant of DCMD contacts with membrane directly. The model also suggested that increasing the cooling plate thermal conductivity resulted in a higher flux. However, when the cooling plate thermal conductivity was higher than 5 W/m.K, further increases in the thermal conductivity of the cooling plate had a negligible impact on flux. A sensitivity study was undertaken to analyze the combined effects of gap channel inner/outer diameters and gap channel thermal conductivity on flux. It is concluded that the gap thermal conductivity played a more important role in PGMD performance compared to the hydrodynamic flow in permeate and coolant channels. To further improve hollow fibre PGMD performance, six recommendations are provided for the future work.

Sauropods have been one of the most studied dinosaur groups due to their extremely large body size. An open question is what these animals ate to reach such gargantuan sizes. The diets of fossil vertebrates can be determined by examination of microscopic wear patterns on the surface of the teeth, which can distinguish between hard and soft foods and constrain the feeding height and food selectivity of the animal. This study examined the microwear patterns on ten Late Jurassic sauropod teeth from the Morrison Formation of North America, including the diplodocids Barosaurus, Diplodocus, and Suuwassea and the macronarian Camarasaurus, using scanning electron microscopy (SEM). In addition, the capability of a three-dimensional laser scanner, a less expensive and potentially less damaging method than SEM, to image these microwear patterns was tested. The SEM images were analyzed for wear patterns, before they were marked on the images and the lengths and widths of the wear was measured. The 3D images were also examined to test if microscopic wear could be seen on the models. The 3D scans proved too coarse to view microscopic detail while only scratches were found on six of the ten teeth tested. No wear was found on the Barosaurus teeth tested. From this information it was concluded that both Suuwassea and Camarasaurus fit with previous studies indicating both were more selective, mid-height browsers while the single Diplodocus tooth tested did not match the previous study which indicated the animal should be a low level non-selective browser due to the lack of pitting visible on the wear surface. The laser scanner proved unable to create images fine enough to see the microscopic wear on the teeth, which indicates that while still a valuable tool in other circumstances, the 3D scanner has not reached a point where it can completely replace the older SEM method.

This exegesis outlines the procedures, processes and methodologies used in developing a body of studio work that investigates the artistic potential of scientific photomicrography made by the Scanning Electron Microscope (SEM) with a view to its possible social and cultural impact of this practice. The outcomes of this research are of two kinds: theoretical findings and the work developed and exhibited during the candidature and at the final exhibition, H2O+. Reflecting the chemical composition of water and interpreting photomicrographic images of it, my practice seeks to provide insights and awareness about water quality, that might be later used to encourage behavioural change to water management, and demonstrate productive transdisciplinary relationships and innovation between the arts and sciences. Artistic manipulation of a scientific process through experimenting with the SEM fuses science and technology with art and proposes a new meaning for what such images can say about water to a viewer. Transforming the microworld to a macro level causes a dilemma for viewers, mainly because enlarged photomicrographs placed in the gallery space are seen differently from those viewed for their scientific information within the laboratory. An aesthetic engagement with photomicrography gives viewers the possibility to see in the particular configurations of inherent features of water opening a horizon of meaning that was previously unseen as well as referring to the creative ability to observe natural phenomena over and beyond the directly visible. Building on the fact that scientific tools have brought new ways of seeing the world, the primary purpose of this research is to show that the artistic use of SEM-made photomicrography can shift the visual outcomes of scientific photomicrography to function within the context of art.

We have used the physical vapor deposition technique, plasma sputtering, to fabricate single junction n-type amorphous Silicon and amorphous Indium Gallium Nitride on p-type polycrystalline Silicon. We proceeded to study the open circuit voltage, short circuit current, fill factor, efficiency, and activation spectrum of each sample. After, we identified the structural morphology and elemental composition of the complete sample and each individual layer in the scanning electron microscope (SEM) and transmission electron microscope (TEM). Finally, we determined the limitations of our fabrication method and discuss methods of rectifying these limitations.

Abstract: Conaid is a liquid ionic soil stabilizers used as a compaction aid or a stabilizer for soil improvement. The material is a mixture of surfactant, stabilizer and high-charge ion sulfide compound. This product may have the potential benefits of removing absorbed water from soil particles with the aid of compaction which results in an increase in shear strength. Despite these potential advantages, there is a lack of geotechnical testing on the material as well as knowledge on its chemical composition and field performance. As a result, a laboratory testing program was conducted at the University of Alberta between September 2010 and June 2012. In this study, standard ASTM laboratory tests were carried out to examine the potential benefits of Conaid. Two natural soils and two clayey soils (kaolinite, montmorillonite) were selected for this study. A wide range of Conaid contents, varying from 0.01% to 0.5% by weight, were applied in treating soils. The effects on the compaction characteristics, shear strength and volume change in triaxial compression tests were evaluated. In addition, scanning electron microscope (SEM) was used to examine the microstructure of untreated and treated soil samples. The test results show some changes, negligible in some cases, on the mechanical properties of the soils treated with Conaid. Also, both Standard and Modified Proctor compaction tests show negligible or even negative effects on maximum dry density and optimum moisture content of test soils except for kaolinite. However, no significant, consistent increases in the shear strength are observed from consolidated drained triaxial compression tests and unconfined compression tests. There is no obvious alteration in the microstructure of the treated soils when they are examined using a SEM except some minor changes are noted in the soil structure.

The practical issue of Scanning Electron Microscope/Energy Dispersive X-ray Spectrometry (SEM/EDX) instrumentation compatibility for particle analysis is addressed. The physical and chemical characterization of fine particles is carried out inside a public transit bus fueled with biodiesel (BD) and ultra low sulfur diesel (ULSD).The three sorts of square surface patterns represented the morphological characteristics of single inhalable particles in the air inside the bus in Toledo. The size and shape distribution results are compared to those obtained for a bus using ULSD and BD respectively.Only the reproducible results from repeated experiments on ESEM and size distribution obtained by the GRIMM dust monitor are used in this study. The collected filters are analyzed using a computer controlled SEM to obtain aerosol elemental compositions. Factor analysis suggested possible sources of indoor particle levels in public transit bus as motor vehicles, outdoor soil and secondary particle formation. The conclusion is that SEM methodology is a valuable tool for studying the distribution of particulates.A part of this study examines the toxic nature of these engine exhausts under different idling conditions. The results of the PM emission analysis showed that the PM mean value of emission is dependent on the engine operation conditions and fuel type. It is found that lubricant oil, PM ash content, and storage tanks are the major sources of elemental concentrations in the PM.Another part of this study looks at the change from ULSD to BD in different idling mode that is investigated with respect to organic carbon (OC) and elemental carbon (EC) for public transit buses in Toledo, Ohio. The carbon source profile for both alternative fuels for eight carbon fractions is developed through real time experiments. The results indicated that the use of BD instead of ULSD is environmentally sustainable for human health and climate change.A new method for determining kinetic parameters of soot oxidation is applied for exhaust particles collected from public transit buses. The results indicate that the use of BD in public transit buses will result in lower particle formation from the engine. Particle morphology is clearly spherical carbon nano particles with chain-like agglomerates.

We have advanced the state-of-the-art for nano-fabrication of carbon nanotube (CNT) based field emission devices, and have conducted experimental and theoretical investigations to better understand the reasons for the high reduced brightness achieved. We have demonstrated that once the CNT emitter failure modes are better understood and resolved, such CNT emitters can easily reach reduced brightness on the order of 10⁹ A m⁻² sr⁻¹ V⁻¹ and noise levels of about 1%. These results are about 10% better than the best brightness results from a nanotip emitter archived to date. Our CNT emitters have order of magnitude better reduced brightness than state-of-the-art commercial Schottky emitters. Our analytical models of field emission matched our experimental results well. The CNT emitter was utilized in a modified commercial scanning electron microscope (SEM) and briefly operated to image a sample. We also report a successful emission from a lateral CNT emitter element having a single suspended CNT, where the electron emission is from the CNT sidewall. The lateral CNT emitters have reduced brightness on the order of 10⁸ A m⁻² sr⁻¹ V⁻¹, about 10X less than the vertical CNT emitters we fabricated and analyzed. The characteristics of the lateral field emitter were analyzed for manually fabricated and directly grown CNT emitters. There was no significant difference in performance based on the way the CNT emitter was fabricated. We showed that the fabrication technique for making a single CNT emitter element can be scaled to an array of elements, with potential density of 10⁶-10⁷ CNT emitters per cm². We also report a new localized, site selective technique for editing carbon nanotubes using water vapor and a focused electron beam. We have demonstrated the use of this technique to cut CNTs to length with 10s of nanometers precision and to etch selected areas from CNTs with 10s of nanometers precision. The use of this technique was demonstrated by editing a lateral CNT emitter. We have conducted investigations to demonstrate the effects of higher local water pressure on the CNT etching efficiency. This was achieved by developing a new method of localized gas delivery with a nano-manipulator.

Seven series of thin films encompassing metallic, dielectric, and semiconductor materials were deposited onto a substrate by means of electron-beam evaporation. Tilting the substrate at an oblique angle relative to the evaporant source causes an atomic shadowing effect to occur at adjacent deposition locations and results in the growth of a columnar morphology. Scanning electron micrographs for each series validate a film structure and porosity that varies with substrate tilt angle. Angle resolved spectroscopic ellipsometry reveals the anisotropic nature of the different series and determines the optical properties utilizing a best model fit calculation. In some instances, the optical properties of the columnar thin film and its bulk material differ significantly.

Gallium nitride (GaN) and its alloys are used to manufacture green-to-ultraviolet range light emitting diodes (LEDs) for the solid-state lighting industry. However, heteroepitaxial growth on substrates such as 6H-SiC or -Al2O3 results in LEDs with large densities of crystal defects; the optical and electronic properties of these defects, and their influences on LED device performance, are not yet well understood. Controlling and optimizing processing in modern optoelectronic materials, such as GaN, requires a high-resolution characterization technique to probe the localized bandstructure of the materials and their defects in order to relate properties to processing. The beam-injection modes of scanning electron microscopy (SEM) fulfill this need. When an SEM is used to examine a semiconductor, the electron beam injects electron-hole pairs (EHPs) into the semiconductor's band structure. Cathodoluminescence (CL) and electron-beam-induced current (EBIC) are SEM techniques that take advantage of this localized beam-injection of EHPs, and are used to directly probe the optoelectronic behavior of semiconductor materials, devices, and defects. This work examines the optoelectronic properties of defects in GaN-based LED devices. First, computer modeling of the polarization fields in quantum wells was performed, and quantitative predictions of cathodoluminescence peak shifts during electron injection, under varying conditions of electrical bias, were made. Experimental conditions and mathematical treatments for accurate EBIC quantification of the minority carrier diffusion length in GaN light-emitting diodes (LEDs) were developed and refined, as were combined CL and EBIC techniques for the study defect populations in GaN LEDs. Additionally, the effects of focused-ion-beam milling as a cross-sectional sample preparation technique for GaN were studied by CL and EBIC. Limitations and possible extensions to these techniques are also be discussed. By using SEM-EBIC/CL to pinpoint defects in LED devices, site-specific FIB microsampling has been used to prepare samples of defected areas for transmission electron microscopy (TEM). Analyses of these samples have shown how the identity of crystal defects within the devices directly relates to the optoelectronic behavior observed in EBIC and CL.

Sensilla styloconica on the proboscis of 107 species of North American and tropical butterflies were comparatively studied using the scanning electron microscope. Focus was on 76 species of North American Nymphalidae representing 45 genera and 11 subfamilies. Nomenclature for generalized and specific types of nymphalid sensilla is proposed. Written descriptions and micrographs are presented for each species studied. Morphological features were generally consistent for all or most species within genera and sometimes within subfamilies, with specified exceptions. Statistical analysis revealed significant differences for six of eight variables tested between two distinct feeding guilds of North American Nymphalidae. Average number, density, extent of proboscis coverage with sensilla, their total length, and shoulder spine length were all significantly greater in the non-nectar feeding guild than in nectar feeders, and may indicate adaptation for greater efficiency in feeding on flat surfaces. The greater frequency of apical shoulder spines in non-nectar feeders may represent adaptation for protection of sensory pegs from mechanical abrasion during feeding, or for anchoring the flexible proboscis tip to the surface. Correlation analysis revealed 9 out of 28 positive correlations in nectar feeders and 5 out of 28 in non-nectar feeders. Results of preliminary cladistic analysis were not considered to be meaningfully robust due to few available characters. The stylar characters identified in this study should be more useful in future analyses when included with characters from other lines of evidence. The presence of sensilla styloconica in all subfamilies of Nymphalidae, except Danainae, largely supports Ehrlich's (1958) higher classification concept for the family. The presence of less conspicuous sensilla in the Danainae, and other characteristics are presented as further evidence that they should be reconsidered for full family status. Sensilla styloconica in nymphalid butterflies appear to function as extensions that provide greater sensory reach during feeding. The role of these sensilla in liquid uptake, pollen feeding, and host plant selection is discussed.

Several identification techniques were used with the following: Auricularia (2spp.), Peniophora (1sp.), Chondrostereum (1sp.), Agaricus (5 spp.), Amanita (2 spp.), Agrocybe (2 spp.), Panaeolus (1 sp.), Marasmius (1 sp.), Laccaria (2 spp.), Paxillus (1 sp.) and Russula (2 spp.). All species were not studied with every technique. Initial identifications were based on morphological macro-features. Light microscopy was used to study features of Agaricus (2 spp.), Russula (1 spp.), and Laccaria (1 spp.) to determine their importance in identification. Scanning electron microscopy was used to determine the size and surface structure of basidiospores of Auricularia (2 spp.), Agaricus (5spp.), Amanita (2 spp.), Agrocybe (2 spp.), Panaeolus (1 sp.) Marasmius (1 sp.), Laccaria (2 spp.), Paxillus (1 sp.), and Russula (2 spp.). Surface structure was found to be more useful in the delineation of genera and species than spore dimensions. Several methods for preparing spores for viewing in the scanning electron microscope (SEM) were evaluated . Critical point drying of hymenial fragments produced good results from fresh or rehydrated material and was found to be better than other methods. Fixation was not of value in preparing spores. Chemical tests were used on Agaricus (3 spp.), Amanita (1 sp.),Agrocybe (1 spp.), Laccaria (2 spp.), and Russula (2 spp.). No single chemical test separated all species studied, but some, such as Melzers reagent and potassium hydroxide proved to be useful in the separation of some species. Amino acid profiles were developed for Agrocybe parasitica and Agaricus vaporarius and comparison of levels with those published for other species revealed differences, but not considered important in identification. lsozyme polyacrylamide gel electrophoresis (PAGE) of the pileus, hymenium and stipe of fruiting bodies of Auricularia (1 sp.) Agaricus (5 spp.),Amanita (2 spp.),Marasmius (1 sp.), Paxillus (1 sp.), and Agrocybe (1 sp.), and mycelia of Agrocybe (2 spp.), Auricularia ( 1 sp.), Peniophora (1 sp.), Chondrostereum (1sp.), and Agaricus (1sp.) was carried out using stains for catechol oxidase, succinate dehydrogenase and alcohol dehydrogenase. Extracts of the pileus, hymenium and stipe from most species produced different banding patterns when stained for each of the 3 enzymes studied. When stained for the activity of each enzyme, different overall banding patterns were recorded for the fruiting body of each species as well as for the mycelial extracts studied. Of the three enzymes, catechol oxidase was of greatest value as extracts from all species not only reacted more quickly and positively but extractions were easier to perform. lsozyme PAGE is of value for the identification of members of the Hymenomycetes and potential exists for incorporation of isozyme banding patterns into data bases used for identification. However, further samples from different locations must be studied to determine the intraspecific variation, and thus confirm the value of isozyme PAGE in mushroom species identification. Low molecular weight (LMW) RNA PAGE enabled the seperation of 2 species of Agaricus. LMW RNA profiles could provide a means of identifying subspecies with less variation in banding pattern than might be observed using isozyme PAGE. Again further study of samples from different locations is necessary to determine the true value of LMW RNA for fungal identification.