Method and apparatus for detecting laminar flow separation and reattachment

The invention is a method and apparatus for detecting laminar flow separation and flow reattachment of a fluid stream by simultaneously sensing and comparing a plurality of output signals, each representing the dynamic shear stress at one of an equal number of sensors spaced along a straight line on the surface of an airfoil or the like that extends parallel to the fluid stream. The output signals are concurrently compared to detect the sensors across which a reversal in phase of said output signal occurs, said detected sensors being in the region of laminar separation or reattachment. The novelty in this invention is the discovery and use of the phase reversal phenomena to detect laminar separation and attachment of a fluid stream from any surface such as an airfoil supported therein

A map and a pipe : a new approach to characterizing erosion-corrosion regimes of Fe in three dimensions using CFD modelling

In studies of erosion-corrosion, much work has been carried out in recent years to identify regimes of behaviour. Such regimes describe the transition between the erosion and corrosion dominated mechanisms. They can also be used, by assigning various criteria, to identify other regimes of behaviour such as extent of "synergy/antagonism" in the process, so-called "additive" behaviour and the extent of wastage. Despite this work, there has been very little effort to combine the two dimensional erosion-corrosion map with CFD modelling approaches, in which the characteristics of the fluid are accounted for in the regime description. This means that extrapolation of such maps in two dimensions to a three dimensional real surface presents some difficulties. However, it is these surfaces that corrosion engineers are required to tailor, either through modification of the material composition, the surface or the process parameters, for optimum erosion-corrosion resistance. In this paper, a methodology is generated to combine the concepts of CFD modelling, and the erosion-corrosion regime map for a specific geometry and for a range of pure metals in descending order in the Galvanic series. The changes in regimes are presented as a function of variation in the erosion and corrosion variables i.e. particle size, hardness and solution pH. Erosion-corrosion regimes are presented, based on the model results, showing the wide range of mechanistic and wastage mechanisms possible over the component surface

Tribo-corrosion of steel in artificial saliva

Stainless steel is widely used as dental implant. However, there has been little work on the micro-abrasion of such materials in laboratory simulated oral environments, where abrasion, sliding wear can interact simultaneously. In this study, the effects of applied load, and exposure time were evaluated for a 316 stainless steel in a laboratory simulated artificial saliva. Polarization curves showed an enhancement of corrosion current density with increases in applied load. Wear maps were produced showing low wear safety regimes at intermediate loads and exposure times. Possible reasons for such trends are interpreted in terms of the ability of the passive film in providing resistance against third body particle impact and the concentration of particles in the contact at higher loads

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

Distribution of the Water Scorpion \u3ci\u3eNepa Apiculata\u3c/i\u3e (Hemiptera: Nepidae) in Wisconsin

The water scorpion Nepa apiculata Uhler was considered rare in Wiscon- sin by Hilsenhoff (1984), who collected only 11 individuals during a 25-year period. All of his collections were from overwintering sites, especially debris in streams, during early spring or autumn (Hilsenhoff, pers. comm.). He concluded that the species was restricted to southern Wisconsin. Recent collections indicate that N. apiculata is more widely distributed. These records, summarized below, are documented with specimens in the University of Wisconsin-Madison insect collection

The presence of foreign firms in Ghana: the role of physical, financial, and governance infrastructure. Final report

Using a new wave of firm-level data from the World Bank’s Enterprise Surveys this study examines the linkages between foreign firm participation and the investment climate in Ghana. The analysis of the binding constraints of direct investment is split between objective and subjective measures of the investment climate. While the subjective measures indicate accessing finance is the main constraint to doing business, the objective measures suggest foreign firm participation is affected by a multiplicity of institutional, physical and finance related infrastructures, namely the administration of financial statements, power outages and the judicial system. A breakdown of the effects of the binding constraints by ownership, firm size, industry and region is also provided

Intentional and unintentional non-adherence in community dwelling people with type 2 diabetes: the effect of varying numbers of medicines

People with type 2 diabetes are often prescribed multiple medicines which can be difficult to manage. Nonadherence to medicines can be intentional (e.g. active decision) or unintentional (e.g. forgetting). The objective of this study was to measure intentional and unintentional non-adherence to differing numbers of medicines prescribed in type 2 diabetes. A cross sectional survey using the Morisky medication adherence scale (with intentional and unintentional non-adherence subscales) was completed by 480 people prescribed oral antidiabetic drugs (OADs), antihypertensive agents and statins. A within-subject analysis of variance (ANOVA) showed that intentional non-adherence did not vary between OADs, anti-hypertensives and statins. Intentional non-adherence to statins significantly increased when the number of medicines prescribed was included as a between-subjects variable (p<0.05). Another within-subject ANOVA on unintentional non-adherence found a significant difference between OADs, anti-hypertensives and statins; unintentional non-adherence to OADs was significantly higher (p<0.05). When the number of medicines was added as a between-subject variable unintentional non-adherence was associated with higher numbers of medicines. This study shows the difference between intentional and unintentional non-adherence behaviours, and the effect that varying numbers of medicines can have on these behaviours

Glueball masses in U(1) LGT using the multi-level algorithm

The multi-level algorithm allows, at least for pure gauge theories, reliable measurement of exponentially small expectation values. The implementation of the algorithm depends strongly on the observable one wants to measure. Here we report measurement of glueball masses using the multi-level algorithm in 4 dimensional compact U(1) theory as a case study.Comment: Lattice 2003 (algorithm) 3 pages, 3 figures and 2 table

A dearth of legislative vetoes: why the Council and Parliament have been reluctant to veto Commission legislation

Several reforms have taken place at the EU level to try and address the criticism that EU decision-making suffers from a democratic deficit. Drawing on recent research, Michael Kaeding and Kevin M. Stack assess one such reform: the provision of powers for the Council of the European Union and the European Parliament to veto so called ‘secondary legislation’ put forward by the European Commission. They find that the use of these veto powers has been extremely limited, although this does not necessarily mean the reforms have been ineffective, but rather that they may have impacted on the bargaining dynamics of informal negotiations between the institutions