Accurate determination of surface texture is essential for the manufacturing of mechanical components within design specifications in engineering and materials science disciplines. It is also required for any subsequent modifications to physical properties and functional aspects of the object. A number of methods are available to characterize any surface through the measurement of roughness parameters that can then be used to describe surface texture. These methods may be divided into those in that direct contact is made with the surface and those where such contact is not required. This report describes two methods approach for the surface profiling of a quartz glass substrate for step height, and tungsten substrate for roughness measure. A stylus profilometer (contact method) and vertical scanning interferometer, (VSI) or (non-contact optical method) were used for step height and roughness parameter measurements. A comparison was made with nominal values assigned to the studied surface, and conclusions drawn about the relative merits of the two methods. Those merits were found to differ, depending on the parameters under consideration. The stylus method gave better agreement of step height values for dimensions greater than a micron. Both methods showed excellent accuracy at smaller dimensions. Both methods also provided accurate average roughness values, although the VSI data significantly overestimated 35% above the peak-to-valley parameter. Likely sources and nature of such differences are discussed based on the results presented, as well as on the previous comparison studies reported in the literature. Because of such method-specific differences, the multi-technique approach used in this work for accurate surface profiling appears to be a more rational option than reliance upon a single method. Both contact and non-contact approaches have problems with specific roughness parameters, but a hybrid approach offers the possibility of combining the strengths of both methods and eliminating their individual weaknesses.

It is commonly known that coastal vegetation dissipates energy and aids in shoreline protection by damping incoming waves and depositing sediment in vegetated regions. However, this critical role of vegetation to dampen wave forces is not fully understood at present. A series of laboratory experiments were conducted in the Haynes Coastal Laboratory and 2-D flume at Texas A&M University to examine different vegetative scenarios and analyze the wave damping effects of incident wave height, stem density, wave period, plant type, and water depth with respect to stem length. In wetland regions vegetation is one of the main factors influencing hydraulic roughness. Traditional open-channel flow equations, including the Manning and Darcy- Weisbach friction factor approach, have been successfully applied to determine bottom friction coefficients for flows in the presence of vegetation. There have been numerous relationships derived relating the friction factor to different flow regime boundary layers to try and derive a wave friction factor for estimating energy dissipation due to bottom bed roughness. The boundary layer problem is fairly complex, and studies relating the wave friction factor to vegetation roughness elements are sparse. In this thesis the friction factor is being applied to estimate the energy dissipation under waves due to artificial vegetation. The friction factor is tuned to the laboratory experiments through the use of the numerical model COULWAVE so that the pipe flow formulation can be reasonably applied to wave problems. A numerical friction factor is found for each case through an iterative process and empirical relationships are derived relating the friction factor for submerged and emergent plant conditions to the Ursell number. These relationships can be used to reasonably estimate a wave friction factor for practical engineering purposes. This thesis quantitatively analyzes wave damping due to the effects of wave period, incident wave height, horizontal stem density, water depth relative to stem length, and plant type for a 6 m plant bed length. A friction factor is then determined numerically for each of the laboratory experiments, and a set of equations is derived for predicting a roughness coefficient for vegetation densities ranging between 97 stems/m2 and 162 stems/m2.

Abstract This study is to examine the phenomena caused by rolling action of a nano-particle against the work surface. The analysis was done by the molecular dynamics method. The distributed computing scheme was adopted in these simulations to increase the computing efficiency. The study includes the interfacial force between the nano-particle, the work and the roughness of the work surface, and the damage layer thickness of the work surface. It is done by first identifying the main factors, and then to understand how the phenomena is affected by these factors. Finally, the results of these simulations were discussed. The results show that the interactive force most comes from the breaking process between the work surface and the nano-particle. When the nano-particle¡¦s rolling speed is increased, the interactive force is enhanced. But if the speed has reached a high value, the interactive force will be saturated. The interactive force is not significantly affected by temperature. When the adhesive strength between the nano-particle and the work is higher, the interactive force is higher. The roughness of the work surface is affected by the rolling speed of the nano-particle, the temperature, and the adhesive strength between the nano-particle and the work. If the temperature or the interactive force is higher, the roughness of the work surface is higher. If the rolling speed is higher, the roughness of the work surface will increase. But if the rolling speed has reached a high value, the roughness of the work surface will not increase. The damage layer thickness of the work surface is little affected by the rolling speed of the nano-particle or temperature or the adhesive strength between the nano-particle and the work surface.

Physical stress such as the surface roughness of the implants may activate the NFkB signalling pathway in macrophages. This activation is intimately related to the mechanism(s) by which the macrophage interacts with the surface through serum proteins and/or the formation of membrane rafts. This thesis examines the role of surface topography on activation of the NFkB signalling pathway in macrophages. We examined the effect of implant surface topography on activating the NFkB signalling pathway in the RAW 264.7 macrophage cell line. We also examined the effect surface roughness had on the adhesion of the macrophages using the different media. To finish, we observed the effect the different media and the surface roughness had on the morphology of the macrophages by Scanning Electron Microscopy. Activation of the NFkB pathway was surface topography dependent. The Smooth surface showed the highest level of activation followed by the Etched then the SLA. Addition of suboptimal concentrations of LPS mildly enhanced the response by signalling through the Toll receptor. Activation of NFKB occurred in the absence of fetal calf sera, although to a lesser extent. All three surfaces had very few cells with nuclear translocation at the 5 minutes time point with no significant statistical differences between the surfaces. After 30 minutes, translocation reached comparable levels to those surfaces tested with complete medium. Disruption of the lipid rafts affected the triggering and signalling of the NFkB pathway. This inhibitory effect was concentration and time dependent. Smooth surfaces bound more macrophages in the 30 minutes assay. Fetal calf serum appeared to be very critical for adhesion and spreading of the macrophages on the various surfaces examined. Removal of cholesterol did not affect adhesion or spreading on their respective surfaces. We have clearly demonstrated that the lipid rafts along with surface topography play a role in the activation on NFKB. This in-vitro study has demonstrated that surface topography modulated activation of the NFKB signalling pathway in a time-dependent manner. However, at present, it is unclear through which receptor(s) / surface structure the signal pathway is initiated.

No description available.

Recently a new x-ray absorption spectroscopy (XAS) called inverse partial fluorescence yield (IPFY) has been developed that is bulk sensitive and free of saturation effects, which also provides a direct measure of total absorption coefficient. However, IPFY was originally formulated for smooth bulk samples, but XAS is often performed on rough samples. To test the applicability of IPFY on rough surfaces, a model is presented and the calculations based on this model are compared to the experimental results measured on NdGaO3. It is shown that the correspondence between calculated and experimental intensities of IPFY is sufficient to corroborate this model a means of estimating the maximum allowable surface roughness size and the optimal detection geometry.

The interfacial structure of Co/Cu multilayers deposited under energetic ion bombardment has been investigated using X-ray reflectivity techniques. An ionassisted deposition system, based on unbalanced magnetron sputtering principles, has been developed in order to provide a method for the independent control of ion flux and energy. Using this system ion current densities measured at the substrate could be varied from ~30 µAcm2 to ~100 µAcm2 and average ion energies of ~50-200 eV could be selected. It was therefore possible to prepare Co/Cu multilayers under a variety of ion bombardment conditions and thus study the effect of this energetic particle bombardment on the evolution of interface structure. Samples were characterised by measuring the specular and diffuse X-ray reflectivity, using anomalous scattering effects to enhance the contrast between the cobalt and copper layers. Quantitative analysis of the specular reflection revealed the existence of variations of the interface roughness in multilayers deposited under ~200 eV ion bombardment, such that the interfaces became smoother towards the free surface. Films deposited with the highest available levels of ion flux were found to display the greatest interface smoothing effect. However, no such variation was observed when ion energies of ~50 eV were applied, although differences in the large lateral scale correlated roughness were observed between ~50 eV ion-assisted and non ion-assisted samples. The sensitivity of the interface structure to energetic bombardment during growth is thus demonstrated and the results are discussed in terms of resputtering and ion bombardment induced reordering of the growing surface. It is shown that these effects can be exploited to obtain multilayers with atomically smooth interfaces.

Physical stress such as the surface roughness of the implants may activate the NFkB signalling pathway in macrophages. This activation is intimately related to the mechanism(s) by which the macrophage interacts with the surface through serum proteins and/or the formation of membrane rafts. This thesis examines the role of surface topography on activation of the NFkB signalling pathway in macrophages. We examined the effect of implant surface topography on activating the NFkB signalling pathway in the RAW 264.7 macrophage cell line. We also examined the effect surface roughness had on the adhesion of the macrophages using the different media. To finish, we observed the effect the different media and the surface roughness had on the morphology of the macrophages by Scanning Electron Microscopy. Activation of the NFkB pathway was surface topography dependent. The Smooth surface showed the highest level of activation followed by the Etched then the SLA. Addition of suboptimal concentrations of LPS mildly enhanced the response by signalling through the Toll receptor. Activation of NFKB occurred in the absence of fetal calf sera, although to a lesser extent. All three surfaces had very few cells with nuclear translocation at the 5 minutes time point with no significant statistical differences between the surfaces. After 30 minutes, translocation reached comparable levels to those surfaces tested with complete medium. Disruption of the lipid rafts affected the triggering and signalling of the NFkB pathway. This inhibitory effect was concentration and time dependent. Smooth surfaces bound more macrophages in the 30 minutes assay. Fetal calf serum appeared to be very critical for adhesion and spreading of the macrophages on the various surfaces examined. Removal of cholesterol did not affect adhesion or spreading on their respective surfaces. We have clearly demonstrated that the lipid rafts along with surface topography play a role in the activation on NFKB. This in-vitro study has demonstrated that surface topography modulated activation of the NFKB signalling pathway in a time-dependent manner. However, at present, it is unclear through which receptor(s) / surface structure the signal pathway is initiated.

Thesis (M.S.) in Mechanical Engineering--University of Maine, 2007. / Includes vita. Includes bibliographical references (leaves 106-111).

Thesis (Ph. D.)--University of Rhode Island, 2003. / Typescript. Includes bibliographical references (leaves 108-111).