At the interface between a metal and dielectric, it is possible for an electromagnetic wave to couple with the conduction electrons of the metal to create a coupled oscillation known as a surface plasmon. These surface plasmons can exhibit properties which are not shared with their purely electronic or electromagnetic components. Such unique properties include the ability to transmit plasmonic waves through sub-wavelength spaces, opening up the possibility of combining the high data density seen in photonics-based information technologies with the nanometer-scale electronic components of modern integrated circuitry. Other plasmon properties such as the highly resonant nature of plasmon excitation may potentially lend themselves to novel cancer treatments and medical probing techniques. In order to develop such technologies, a deeper understanding of surface plasmons and their relationship with a material’s properties and structure is necessary. In the present work, angle- and energy-resolved optical measurements for a square lattice of circular Fe20Pd80 islands are presented in the form of reflectivity and transmission maps, along with higher resolution reflectivity, transmission, and TMOKE measurements for a few specific wavelengths. A theoretical model describing the connection between plasmonic and magneto-optical behavior is described and compared with the experimental data, showing a very high correlation.

The surface tension of an interface separating two bulk phases is one of the most widely studied properties in surface science research. The importance of surface or interfacial tension is reflected in the diverse number of applications which are influenced by surface tension related effects. This thesis represents a comprehensive experimental and theoretical investigation on molecular adsorption and surface tension from a class of organic compounds in aqueous solutions. The research illustrates the effect of both liquid and vapor phase adsorption on the interfacial properties. Adsorption from both sides of the vapor/liquid interface is considered simultaneously rather than exclusive of one another, which has been the conventional practice. In the experimental study, the surface tension of a number of different volatile organic compounds is measured using the Axisymmetric Drop Shape Analysis-Profile (ADSA-P) method. The experiments were performed in a controlled environment under conditions where the surface tension can be affected by both vapor and liquid phase adsorption. The vapor phase was exerted by the presence of an environment solution containing the same organic component as in the drop solution. The results show that initially the surface tension is influenced by the organic concentration in both the liquid and the vapor phase. At the final steady-state the liquid phase becomes less important and the primary factor influencing the surface tension is the vapor phase concentration. The ADSA-P technique is verified by reproducing a select number of cases using the Wilhelmy plate method. A possible consequence of the surface tension phenomenon is illustrated through time-dependent contact angle experiments. The behavior of the interface at steady-state conditions is investigated by measuring the surface tension response to a change in drop volume. It is concluded that the organic compounds considered in the current study may represent a rather general group of molecules whose surface behavior is unique to that of many conventional surfactants. In the theoretical study an empirical model is proposed to describe the relation between the steady-state surface tension and the concentration of the environment and drop solutions. The results confirm the experimental observation that the final steady-state surface tension is determined primarily by the organic concentration in the vapor phase. In addition, a modified adsorption isotherm is developed to account for simultaneous adsorption from both sides of the vapor/liquid interface at steady-state conditions. The derivation is based upon the classic Langmuir analysis, and the new equation is consistent with the Langmuir isotherm under traditional conditions where adsorption occurs from one side of the interface. The modified isotherm is shown to be consistent with the experimental data and is used to generate the equilibrium parameters for three of the systems studied in this research. The adsorption isotherm is then extended to model the dynamic adsorption process through the creation of a new kinetic transfer equation. As with the adsorption isotherm, the transfer equation is based on Langmuir kinetics and is capable of simulating adsorption from both sides of the interface during surface equilibration. The kinetic transfer equation is validated against experimental data from two systems which exhibit a transfer-controlled adsorption mechanism. The theoretical predictions from the transfer equation fit well with the experimental data for both systems. However, significant variability is observed in the least squares estimates of the kinetic rate constants. The variability is attributed to the limitations of empirical models that utilize adjustable fitting parameters to optimize the model predictions, and the wide range of surfactant concentrations studied. Specific concentration regions are identified where the variability in the rate constants is minimal and thus, where the model is most appropriate.

In May-June 1978 and 1979 surface collections were undertaken at Jensen's Farm, an early twentieth century homesteading site twenty miles north of Dauphin, Manitoba, to determine the extent to which the results obtained through site surface collection could: 1) be replicated in terms of the frequencies and spatial distributions of artifact classes recovered, and 2) consistently isolate the location, size, shape, and function of the original features known to have existed at Jensen's Farm. Frequency tables, chi-square, and SAS-produced artifact plots were used in conjunction with scale drawings of Jensen's Farm to assess the results obtained. The results suggest that, even on a highly disturbed site such as Jensen's Farm, it is possible to replicate the general rank-order of artifact classes recovered and the general patterns and dispersions of artifacts plotted. Acceptable ranges of variation, rather than results of no significant statistical difference, should be expected given the indeterminate nature of intervening factors and the basic incomparability of artifact fragments as comparative units. Correspondence to the original Jensen's Farm features proved to be a partial one in terms of both the artifact content recovered and the spatial distributions plotted. Based on the results obtained here, it is advocated that surface collection be conducted wherever irreversible resource management decisions are to be made or where time and funding permit the luxury.

The sea surface microlayer is the upper thin interfacial boundary between ocean water and atmospheric air. The microlayer is known to be influenced by surface-active substances (SAS), largely organic matters adsorbed on the ocean surface. SAS samplers have been developed to investigate the chemical composition and effects of SAS but these samplers lack fast sampling and ease of use. To overcome these deficiencies, a new and novel microlayer sampler equipped with a set of rotating glass disks for fast sampling was built and modified. In this project, two closely connected scientific issues associated with the sampler were addressed. Firstly, the thickness of the solution layer adsorbed onto the glass disk was investigated in laboratory experiments using a range of optical techniques. Secondly, the sampler itself was evaluated in different oceanic environments and operated with a range of additional scientific sensors. / Graduate

A spectrally integrated response method is proposed for analyzing transmission data from nanohole array sensors. This method increases the sensitivity by reducing noise and taking more information from the spectrum for bulk and surface sensing. Results from both real experiments and idealized simulations are presented. Comparison with two other methods- peak transmission wavelength shift and a normalized difference integrated response method are shown. This method shows improved sensing performance which can be exploited in future. Further improvement in sensing using nanohole arrays is explored by improving the instrumentation of the sensor system. Design parameters of the nanohole arrays for transmission at two different operating wavelengths were examined by using finite difference time domain simulations. Focused ion beam milling was used to fabricate chosen arrays. A microfluidic chip with the embedded nanohole array sensor was used to introduce different solutions for bulk chemical sensing. Intensity measurements were taken with a high speed CMOS camera. Sensing results using this system with possible improvements shows promise for future sensing applications. / Graduate

The scale-bound view of landsurfaces, being an assemblage of certain landforms, occurring within limited scale ranges, has been challenged by the scale-free characteristics of fractal geometry. This thesis assesses the fractal model by examining the irregularity of landsurface form, for the self-affine behaviour present in fractional Brownian surfaces. Different methods for detecting self-affine behaviour in surfaces are considered and of these the variogram technique is shown to be the most effective. It produces the best results of two methods tested on simulated surfaces, with known fractal properties. The algorithm used has been adapted to consider log (altitude variance) over a sample of log (distances) for: complete surfaces; subareas within surfaces; separate directions within surfaces. Twenty seven digital elevation models of landsurfaces arc re-examined for self- affine behaviour. The variogram results for complete surfaces show that none of these are self-affine over the scale range considered. This is because of dominant slope lengths and regular valley, spacing within areas. For similar reasons subarea analysis produces the non-fractal behaviour of markedly different variograms for separate subareas. The linearity of landforms in many areas, is detected by the variograms for separate directions. This indicates that the roughness of landsurfaces is anisotropic, unlike that of fractal surfaces. Because of difficulties in extracting particular landforms from their landsurfaces, no clear links between fractal behaviour, and landform size distribution could be established. A comparative study shows the geomorphometric parameters of fractal surfaces to vary with fractal dimension, while the geomorphometry of landsurfaces varies with the landforms present. Fractal dimensions estimated from landsurfaces do not correlate with geomorphometric parameters. From the results of this study, real landsurfaces would not appear to be scale- free. Therefore, a scale-bound approach towards landsurfaces would seem to be more appropriate to geomorphology than the fractal alternative.

No description available.

Thermal mapping, the measurement of road surface temperatures (RSTs) with an infra-red thermometer (IRT) mounted in a moving vehicle, seeks to identify a 'characteristic and repeatable' thermal fingerprint (temperature profile) for any stretch of road. A number of uses have been suggested for the process, including ice detection sensor network design and identifying stretches of road for selective gritting, with potential financial and environmental benefits due to reduced salt usage. The project 'Thermal Mapping for a Highway Gritting Network' has resulted in the most extensive survey yet undertaken. The aims were to investigate the reliability/repeatability of fingerprints and establish confidence limits. Comprehensive mapping of Sheffield roads took place during winters 1988/89- 1991/92. Significant errors (+/-3°C) in RST readings were identified after the first winter. Laboratory and road tests confirmed errors were produced due to warming/cooling of the IRT. Operating the IRT in a temperature control box eliminated these errors. Seven Sheffield routes were mapped during winters 89/90 and 90/91 with route 1 fingerprints (100) used for most of the analysis. The main factors affecting the variation in RSTs were confirmed as altitude and land-use with localised peaks occurring under bridges and by trees and tall buildings. The occurrence of cold air drainage on clear/calm (extreme') nights resulted in 'low' RSTs at relatively low altitudes. Differences were identified between what should have been identical extreme fingerprints. These were related to variations in the behaviour of cold air drainage. rom night to night and variations in wind direction/speed interacting with local relief. Confidence limits for extreme fingerprints and maps, taking into account possible errors in mapping and differences between fingerprints, were +/-20C and +/- 2.5°C respectively. With important decisions concerning gritting made when RSTs are +/-5°C confidence limits of this magnitude have important implications for thermal mapping. Future use should be restricted to sensor network design and assessment/re-design of gritting network.

No description available.

No description available.