Tribo-corrosion mechanisms of stainless steel in soft drinks

Tribo-corrosion mechanisms of 316L Stainless Steel in slurries containing common household soft drinks have been studied through investigating the micro-abrasion-corrosion performance using a ball and disk apparatus which has been modified to measure the in-situ corrosion current during the abrasion process. The objective of this study was to evaluate the effect of pH and solution viscosity on the micro-abrasion-corrosion performance of the material. 316L Stainless Steel was selected because it is commonly used as a dental replacement material. This is an important area of work as the use of steel retainers as well as other stainless steel dental replacements is still widespread and the effectiveness of these devices will be determined by their tribological and tribo-corrosion performance. Additionally, an attempt has been made to investigate the importance of the pH and viscosity variables on the tribo-corrosive synergism, wastage and mechanism maps

How is psychological therapy experienced by ex UK armed forces members? An exploration through personal narrative of cross-cultural encounters

The aim of the study was to explore through narrative inquiry the lived experiences of ex-UK armed forces members of psychological therapy, and contribute much needed qualitative findings to a research field currently dominated by quantitative studies. Interview conversations were conducted with ten participants who had served in the UK armed forces and had had weekly psychological therapy over a period of at least a few months since leaving. Narrative inquiry was adopted in analysing the transcripts, and two overarching themes emerged. First, participants revealed a strong identification with, and sense of belonging to the military, often referred to as ‘the family’. Participants implicitly and explicitly retained the values and ideology of the armed forces, such as high standards of personal conduct, structure, order and teamwork. Themes of power and agency also emerged, related to the ‘chain of command’ structure of their previous lives. Second, participants shared the strongly held belief in a significant gulf between military and civilian worlds, a divide that was exacerbated by the lack of a common language and vast differences in everyday professional and personal experiences. Challenges for therapy, particularly with civilian therapists, included how power and control were negotiated and the development of trust. Fear of not being understood or of being judged often led to clients withholding their military experiences in therapy. With military therapists there were different barriers to openness relating to rank and power, stigma, and the fear of personal information going on record and affecting promotion. Successful therapy was facilitated by a friendly, relational style in therapists, and robustness in the face of high emotion. It is recommended that therapists gain at least a rudimentary understanding of military culture, to appreciate the (real and perceived) military/ civilian divide, and to approach working with this client group in terms of cultural difference. Drawing on the ten narratives, twelve specific reflections are offered to enhance practice

Micro-abrasion-corrosion interactions of Ni-Cr/WC based coatings : approaches to construction of tribo-corrosion maps for the abrasion-corrosion synergism

The process of micro-abrasion-corrosion has been the subject of much research in recent years due to the fact that the action of micron sized particles, typically less than 10 um in diameter, can cause significant degradation of materials in many diverse environments involving aqueous corrosion. Cermet based coatings are often used to combat micro-abrasion-corrosion, but has been little work carried out to characterize the performance of such coatings exposed to micro-abrasion-corrosion or to provide a basis for coating optimisation. In addition, a basis for defining the various micro-abrasion-corrosion interactions has not been suggested to date. In this study the micro-abrasion-corrosion performance of a Ni-Cr/WC coating was assessed and compared to the performance of the steel substrate. The results were used to identify regimes of micro-abrasion as a function of applied load and pH of the solution. In addition, micro-abrasion-corrosion maps were constructed based on the results, showing the variation between micro-abrasion-corrosion regimes, as a function of applied load and pH of the solution

Manchurian Rootstocks Influence EAB Resistance When Grafted to North American Ash

Emerald ash borer (EAB; Agrilus planipennis Fairmaire Coleoptera: Buprestidae) is an invasive phloem-boring pest from Asia that has killed tens of millions of North American ash trees (Fraxinus spp.). In its native range, EAB only attacks highly stressed ash trees, functioning as a secondary pest. Because Asian ash shares a co-evolutionary history with EAB, they possess a suite of secondary defensive compounds that prevent EAB from successfully colonizing healthy trees. However, all North American ash trees, regardless of health, are susceptible to EAB, and typically die within four years of infestation. Propagating ash resistant to EAB is crucial to maintaining the North American ash resource. Because many secondary metabolites utilized in plant defense are synthesized in the roots, interactions between the roots and shoots of the tree are critical in host plant resistance. Grafting utilizes this root-shoot connectivity to confer desirable traits, such as resistance to a pest or pathogen, from the rootstock of a plant to its scion. In chapter 1, I review the literature on EAB and its life history, mechanisms of host plant resistance, the practice of horticultural grafting, and root-shoot interactions in grafted plants. In chapter 2, I determine the extent to which resistant Manchurian ash rootstocks confer EAB resistance to susceptible green ash scions. The resistance capability of the parent stock for grafted trees was validated by assessing woodpecker damage and canopy dieback. Adult EAB survivorship, total leaf area consumption, and fecundity, as well as morphological tree characteristics, were measured in the field on grafted and buffer green and Manchurian ash in Indiana in 2017. Grafting trees with resistant rootstocks holds promise for propagating EAB-resistant ash trees. Although total leaf area consumed was not affected by graft combination, beetles caged on conspecific green ash lived longer and laid more eggs than beetles caged on trees with a Manchurian ash scion or rootstock. Beetle survival did not differ between conspecific Manchurian ash and heterospecific green and Manchurian trees. Beetles caged on trees with Manchurian scions and green rootstocks laid more eggs than beetles on caged on trees with green scions and Manchurian rootstocks, and no beetles caged on conspecific Manchurian ash laid eggs. This result demonstrates that, although any grafted tree with a Manchurian rootstock or scion will be more resistant than a conspecific green tree, rootstock has a greater effect than the scion on traits such as fecundity. My findings demonstrate that EAB resistance can be conferred from rootstock to scion, and that grafting could be used to develop EAB-resistant ash

Studies on the immunosuppressive effects and detection of naturally-occuring toxins

Episodes of toxin-producing phytoplankton occur worldwide, causing both animal and human fatalities. Toxicity occurs through consumption of phycotoxins, including azaspiracid, which accumulate in filter-feeding shellfish. Microcystins are hepatotoxins, produced mainly by freshwater cyanobacteria. Aflatoxins are potent, fungal hepatocarcinogens, which occur mainly in food and feed products. The purpose of this research was to examine the cytotoxic and immunosuppressive effects of aflatoxins (B1, B2 and G1), azaspiracid-1 and microcystin-LR in vitro, using the murine macrophage cell line, J774A.1. The results clearly demonstrated that azaspiracid and microcystin had a significant effect on host defence functions, through deregulation of IL-6, IL-10, IL12p40 and TNF-α cytokine expression. Microcystin exposure significantly decreased IL-1β expression. ‘Toll-like’ receptor (TLR2 and CD14) expression was altered following aflatoxin exposure, while apoptotic marker (caspase-1) expression was affected following microcystin exposure. This knowledge should be taken into consideration in the implementation of detection limits, aimed at minimising risks to human health through toxin exposure. Increased awareness of the hazards presented by toxins led to the requirement for recombinant antibodies for these targets, for incorporation into sensitive detection immunoassays. This thesis describes the production of leprine and avian immune libraries for azaspiracid and microcystin, respectively. Attempts were made to isolate azaspiracid-specific antibodies with little success. Phage display was utilised to successfully isolate two single chain antibody fragments (scFvs) to microcystin from the avian library. Error-prone PCR resulted in the isolation of a mutant clone which displayed a 2.3-fold improvement in sensitivity by ELISA, with an LOD of 1.4 ng/mL. The mutant scFv displayed an altered cross-reactivity profile to the microcystin variants tested using Biacore™ inhibition analysis. The recombinant antibodies were successfully applied to the development of fluorescence-based immunoassay formats. The biotinylated mutant scFv was incorporated into a slide-based assay format on a functionalised glass substrate (IC50 ~ 1 µg/L). This assay had the potential to accurately detect microcystin and its variants, below the regulatory limit of 1 µg/L. The application of these highly-sensitive recombinant antibodies into rapid and inexpensive fluorescence detection systems could aid in the development of an early warning system for toxin outbreaks

Investigation of Boiling Performance of Graphene-coated Surfaces

In this Capstone Project, I sought to investigate the boiling performance of graphene-coated surfaces. Boiling was accomplished in a pool boiling chamber, with samples of graphene-coating SiO2 wafers. I developed a procedure for graphene transfer for sample fabrication. Samples were prepared with graphene grown on copper substrates by chemical vapor deposition (CVD). Graphene was transferred from copper substrates to SiO­2 wafers by a thermal release transfer tape. Copper was etched away from the tape-graphene combination by ferric chloride, and the tape was peeled away after heating, leaving graphene on the SiO2 substrate. Contact angles were measured to verify the beneficial hydrophobic properties of the surface, thereby indicating a successful transfer. Raman spectra were taken of the samples at discrete spots to analyze sample quality and uniformity, before and after boiling. Boiling was controlled by a resistance heater on the back of the SiO2 samples, composed of Indium Titanium Oxide (ITO) and two copper electrodes. Samples were epoxied onto a platform in the boiling chamber, and soldered to a power supply. Heat flux was incrementally increased until critical heat flux (CHF) was reached. Experiments found that the boiling process destroyed the bulk of the graphene on the samples, the resulting curves of which reflected both hydrophobic and hydrophilic behavior from the samples. Heat transfer coefficient and CHF of samples were both found to be superior to a blank SiO2 sample, but graphene destruction in the process proves problematic. Furthermore, leakage of water from the tank may have caused an artificially high CHF for one sample. Further investigation of different transfer methods that prevent graphene from leaving the surface is a primary focus of future research

GEMPAK: An arbitrary aircraft geometry generator

A computer program, GEMPAK, has been developed to aid in the generation of detailed configuration geometry. The program was written to allow the user as much flexibility as possible in his choices of configurations and the detail of description desired and at the same time keep input requirements and program turnaround and cost to a minimum. The program consists of routines that generate fuselage and planar-surface (winglike) geometry and a routine that will determine the true intersection of all components with the fuselage. This paper describes the methods by which the various geometries are generated and provides input description with sample input and output. Also included are descriptions of the primary program variables and functions performed by the various routines. The FORTRAN program GEMPAK has been used extensively in conjunction with interfaces to several aerodynamic and plotting computer programs and has proven to be an effective aid in the preliminary design phase of aircraft configurations

Wall-temperature effects on the aerodynamics of a hydrogen-fueled transport concept in Mach 8 blowdown and shock tunnels

Results are presented from two separate tests on the same blended wing-body hydrogen fueled transport model at a Mach number of about 8 and a range of Reynolds numbers (based on theoretical body length) of 0.597 x 10 to the 6th power to about 156.22 x 10 to the 6th power. Tests were made in conventional hypersonic blowdown tunnel and a hypersonic shock tunnel at angles of attack of -2 deg to about 8 deg, with an extensive study made at a constant angle of attack of 3 deg. The model boundary-layer flow varied from laminar at the lower Reynolds numbers to predominantly turbulent at the higher Reynolds numbers. Model wall temperatures and stream static temperatures varied widely between the two tests, particularly at the lower Reynolds numbers. These temperature differences resulted in marked variations of the axial-force coefficients between the two tests, due in part to the effects of induced pressure and viscous interaction variations. The normal-force coefficient was essentially independent of Reynolds number. Analysis of results utilized current theoretical computer programs and basic boundary-layer theory

The Oyster River Culvert Analysis Project

Studies have already detected intensification of precipitation events consistent with climate change projections. Communities may have a window of opportunity to prepare, but information sufficiently quantified and localized to support adaptation programs is sparse: published literature is typically characterized by general resilience building or regional vulnerability studies. The Fourth Assessment Report of the IPCC observed that adaptation can no longer be postponed pending the effective elimination of uncertainty. Methods must be developed that manage residual uncertainty, providing community leaders with decision-support information sufficient for implementing infrastructure adaptation programs. This study developed a local-scale and actionable protocol for maintaining historical risk levels for communities facing significant impacts from climate change and population growth. For a coastal watershed, the study assessed the capacity of the present stormwater infrastructure capacity for conveying expected peak flow resulting from climate change and population growth. The project transferred coupled-climate model projections to the culvert system, in a form understandable to planners, resource managers and decision-makers; applied standard civil engineering methods to reverse-engineer culverts to determine existing and required capacities; modeled the potential for LID methods to manage peak flow in lieu of, or combination with, drainage system upsizing; and estimated replacement costs using local and national construction cost data. The mid-21st century, most likely 25-year, 24-hour precipitation is estimated to be 35% greater than the TP-40 precipitation for the SRES A1b trajectory, and 64% greater than the TP-40 value for the SRES A1fi trajectory. 5% of culverts are already undersized for the TP-40 event to which they should have been designed. Under the most likely A1b trajectory, an additional 12% of culverts likely will be undersized, while under the most likely A1fi scenario, an additional 19% likely will be undersized. These conditions place people and property at greater risk than that historically acceptable from the TP-4025-year design storm. This risk level may be maintained by a long-term upgrade program, utilizing existing strategies to manage uncertainty and costs. At the upper-95% confidence limit for the A1fi 25-year event, 65% of culverts are adequately sized, and building the remaining 35%, and planned, culverts to thrice the cross-sectional area specified from TP-40 should provide adequate capacity through this event. Realizable LID methods can mitigate significant impacts from climate change and population growth, however effectiveness is limited for the more pessimistic climate change projections. Results indicate that uncertainty in coupled-climate model projections is not an impediment to adaptation. This study makes a significant contribution toward the generation of reliable and specific estimates of impacts from climate change, in support of programs to adapt civil infrastructures. This study promotes a solution to today\u27s arguably most significant challenge in civil infrastructure adaptation: translating the extensive corpus of adaptation theory and regional-scale impacts analyses into localscale action