Calibration of the torsional and lateral spring constants of cantilever sensors

Financial support from the EPSRC (EP/K000411/1) and the University of St. Andrews under an Impact Acceleration Account (EP/K503940/1) are gratefully acknowledged.A method suitable for the calibration of the spring constants of all torsional and lateral eigenmodes of micro- and nanocantilever sensors is described. Such sensors enable nanomechanical measurements and the characterization of nanomaterials, for example with atomic force microscopy. The method presented involves the interaction of a flow of fluid from a microchannel with the cantilever beam. Forces imparted by the flow cause the cantilever to bend and induce a measurable change of the torsional and lateral resonance frequencies. From the frequency shifts the cantilever spring constants can be determined. The method does not involve physical contact between the cantilever or its tip and a hard surface. As such it is non-invasive and does not risk damage to the cantilever. Experimental data is presented for two rectangular microcantilevers with fundamental flexural spring constants of 0.046 and 0.154 N/m. The experimentally determined torsional stiffness values are compared with those obtained by the Sader method. We demonstrate that the torsional spring constants can be readily calibrated using the method with an accuracy of around 15%.PostprintPeer reviewe

Surname typology and the problem of inconsistent classification

This paper analyzes methodological inconsistency in surname classification, and the implications this has for the comparability of different works. Many studies have organized surnames by type, based on each name's "meaning," in order to identify national trends and regional differences in surnaming patterns. However, the ambiguity of "meaning" and the lack of any standard classificatory practice mean that such studies are incomparable. By reviewing P. H. Reaney's and R. A. McKinley's classifications of surnames from the same sources, and identifying discrepancies in their calculations and methods, a case for a standard method of surname classification is made. Only when there is a greater level of consistency in the classification of surnames can the findings of separate studies be reliably compared, allowing for meaningful conclusions on surnaming patterns to be drawn. © American Name Society 2013

Decomposition pathways of an S-nitroso sugar, S-nitroso dithiols and the reaction of S-nitrosothiols with iron complexes

Decomposition pathways of S-nitroso-l-thio-β-D-glucose tetraacetate were studied at physiological pH (pH 7.4) and compared with other low molecular weight S-nitrosothiols. Three large differences in reactivity were observed. A larger than expected rate of reaction for the thermal decomposition and reaction with cysteine was found. The second order rate constant obtained for the copper catalysed decomposition was very small compared with other more reactive S-nitrosothiols. The decomposition pathways of the S-nitrosated derivatives of two 1,4 dithiols and a vicinal dithiol were studied. Rate of reaction via the thermal decomposition pathway v/as found to be much greater for the dinitrosated 1,4 dithiols than the dinitrosated vicinal dithiol. The mononitrosated 1,4 dithiols were found to be reasonably stable in acidic solution suggesting that an interaction between two S-nitroso groups on the same molecule could lead to a rapid decomposition. Conversely the mononitrosated vicinal thiol was found to decompose more rapidly than the analogous 1,4 dithiol compounds in acidic solution and at pH 7.4. The mononitrosated vicinal dithiol decomposed to form quantitative amounts of ammonia at pH 7.4. An interesting feature of the reactivity of the vicinal dithiol towards the i'-nitrosothiol functional group was that the thiol form appeared to be an effective nucleophile as well as the thiolate ion forms. Other thiols have a negligible reactivity, except when deprotonated. It has been found that 5-nitrosothiols can transfer NO to an iron(+2) dithiol complex and iron dithiocarbamate complexes at pH 7.4. The iron complexes all have a high affinity for NO in aqueous solution. Primary S-nitrosothiols were found to be able to transfer directly NO(^+) to the iron(+2) dithiol complex. However when S-nitrosoglutathione reacted with iron dithiocarbamate complexes NO appeared to be transferred. Evidence was also obtained that tertiary S-nitrosothiols could transfer NO to the iron(+2) dithiol complex. Clearly whether NO or NO(^+) is transferred depends on the nature of the S-nitrosothiol and the iron complex. Currently iron(+2) dithiocarbamate complexes are used to detect NO, these findings suggest that the presence of 5-nitrosothiols may compromise this experimental procedure

The relationship between individual differences and human territoriality, within a simulated environment

Territoriality is defined as the acquisition of land or resources, such as food or mates, and securing these resources from actual or perceived threat. Many animals show differences in the expression of territoriality based on sex and personality differences, this study examined the extent these factors mediate territoriality usage, and what form it expresses itself in human participants. First gender (as identified by self-report questionnaire) and personality (scores attained from the Big Five Inventory Questionnaire), were examined, and how this altered in game territorial behaviours. It was found that females tended to use more non-aggressive territorial behaviours than males, and displayed a greater number of overall territorial behaviours than males. These results are consistent with an evolutionary theory of territoriality, whereby females tend towards more passive territorial behaviours, as opposed to males who tend towards more aggressive territoriality. Surprisingly, males did not show this inverse relation of increased aggressive territorial behaviours within this simulation.Secondly, power asymmetries were examined between avatars, based on predictions by Game Theory. It was found that participants assigned to smaller avatars displayed significantly more withdrawing behaviours in general, and in particular towards larger avatars, as compared to the individuals controlling larger avatars. Furthermore smaller avatars used more passive territorial behaviours than larger avatars. This is consistent with a Game Theory approach to territoriality.Finally winner and loser effects were examined in how they mediate emotional word usage in a short storytelling activity. It was found that low survival time is the best predictor of negative emotional word usage, and as survival time increase, negative emotional word usage decreased

Change in the by-names and surnames of the Cotswolds

This thesis builds on previous studies of English by-name and surname history. Many have identified the regionally specific nature of name development in England (McKinley, 1990: 20; Hey, 2000: xi; Redmonds, 2004: xiv), yet most of our knowledge comes from national name surveys (see Reaney, 1967; McKinley, 1990), or research carried out at county level (see Redmonds, 1973; McKinley, 1975, 1977, 1981, 1988; Postles, 1995, 1998). While it has been recognised that our understanding of by name and surname development ‘will need to be focused on particular parts of the country, looking at how groups of names were formed at different times in particular local communities’ (Hey, 2000: xi), there have been no studies of this kind. By carrying out a diachronic study focused primarily on the influence regional identity has had on surname development in the Cotswolds, a region with its own distinct cultural, economic and topographical history, it has been possible to reach a greater degree of accuracy on the causes of regionally specific name development than previously achieved. The names from a time when hereditary surnames had only recently been established, 1381, have been compared with those from a period of greater surname stability, c1600, showing that there had been considerable change in the names of the Cotswolds between these two periods. Often, this change can be related to the regional wool trade. Within the Cotswolds, changes in name distribution, name frequency, the names of migrants, dialect lexis in naming and the incidence of inherited surnames can all be linked with the change in focus from raw wool exportation to cloth production, as well as other historical factors.Through this research project, it is clear that there had been major changes in the names of the Cotswolds between 1381 and c1600, many of which have not been identified in previous research. This suggests that there are some aspects of English by name and surname history that are not yet fully understood, such as the precise period when hereditary surnames became more common than non-hereditary by-names, and any regional variation. The national significance of these changes cannot be known without further regional studies for comparison, and it is hoped that such research will be carried out in response to the findings of this thesis

Contact-free experimental determination of the static flexural spring constant of cantilever sensors using a microfluidic force tool

Financial support from the EPSRC (EP/K000411/1 and EP/L017008/1) and the University of St. Andrews under an Impact Acceleration Account (EP/K503940/1) are gratefully acknowledged.Micro- and nanocantilevers are employed in atomic force microscopy (AFM) and in micro- and nanoelectromechanical systems (MEMS and NEMS) as sensing elements. They enable nanomechanical measurements, are essential for the characterization of nanomaterials, and form an integral part of many nanoscale devices. Despite the fact that numerous methods described in the literature can be applied to determine the static flexural spring constant of micro- and nanocantilever sensors, experimental techniques that do not require contact between the sensor and a surface at some point during the calibration process are still the exception rather than the rule. We describe a noncontact method using a microfluidic force tool that produces accurate forces and demonstrate that this, in combination with a thermal noise spectrum, can provide the static flexural spring constant for cantilever sensors of different geometric shapes over a wide range of spring constant values (≈0.8–160 N/m).Publisher PDFPeer reviewe

The boundedly rational employee: Security economics for behaviour intervention support in organizations

Security policy-makers (influencers) in an organization set security policies that embody intended behaviours for employees (as decision-makers) to follow. Decision-makers then face choices, where this is not simply a binary decision of whether to comply or not, but also how to approach compliance and secure working alongside other workplace pressures, and limited resources for identifying optimal security-related choices. Conflict arises because of information asymmetries present in the relationship, where influencers and decision-makers both consider costs, gains, and losses in ways which are not necessarily aligned. With the need to promote ‘good enough’ decisions about security-related behaviours under such constraints, we hypothesize that actions to resolve this misalignment can benefit from constructs from both traditional economics and behavioural economics. Here we demonstrate how current approaches to security behaviour provisioning in organizations mirror rational-agent economics, even where behavioural economics is embodied in the promotion of individual security behaviours. We develop and present a framework to accommodate bounded security decision-making, within an ongoing programme of behaviours which must be provisioned for and supported. Our four stage plan to Capture, Adapt, Realign, and Enable behaviour choices provides guidance for security managers, focusing on a more effective response to the uncertainty associated with security behaviour in organizations

A comparison between omeprazole and a dietary supplement for the management of squamous gastric ulceration in horses

Although several studies have assessed the short-term effect of dietary supplements on the treatment and prevention of gastric ulceration in horses, few have assessed the response over a duration of more than 30 days. A blinded randomized noninferiority clinical trial was conducted using 42 Thoroughbred horses in race training with squamous ulceration of ≥ grade 2/4, randomly assigned to one of two treatment groups for a period of 90 days: omeprazole at the full label dose of 4 mg/kg or the Succeed digestive conditioning supplement. Noninferiority analyses and Wilcoxon sign rank tests were used to analyze the data. At day 90, Succeed was noninferior to 4 mg/kg omeprazole administered daily in terms of the proportion of horses with complete resolution of squamous ulceration. At day 30, Succeed was found to be inferior to omeprazole in terms of the proportion of horses with grade ≤1/4 squamous ulceration. The proportion of horses with reducing squamous ulcer score (compared with day 0) was statistically significant for both treatments at days 30 and 60. At day 90 of the 17 horses on Succeed, nine had a reducing squamous ulcer score (P value = .049), and of the 19 horses on omeprazole, 10 had a reducing squamous ulcer score at day 90 (P value = .091). The noninferiority of Succeed compared to omeprazole at 90 days for the complete resolution of squamous ulceration and the reduced efficacy of omeprazole following 90 days of treatment are likely to be of interest to practitioners managing gastric ulceration in performance horses

Substituted Pentacenes and Electronic Devices Made with Substituted Pentacenes

Novel substituted pentacenes and electronic devices made with those substituted pentacenes are disclosed

Development and Testing of a Refractory Millimeter-Wave Absorbent Heat Exchanger

Central to the Millimeter-Wave Thermal Launch System (MTLS) is the millimeter-wave absorbent heat exchanger. We have developed metallic and ceramic variants, with the key challenge being the millimeter-wave absorbent coatings for each. The ceramic heat exchanger came to fruition first, demonstrating for the first time 1800 K peak surface temperatures under illumination by a 110 GHz Gaussian beam. Absorption efficiencies of up to 80 are calculated for mullite heat exchanger tubes and up to 50 are calculated for alumina tubes. These are compared with estimates based on stratified layer and finite element analyses. The problem of how to connect the 1800 K end of the ceramic tubes to a graphite outlet manifold and nozzle is solved by press fitting, or by threading the ends of the ceramic tubes and screwing them into place. The problem of how to connect the ceramic tubes to a metallic or nylon inlet pipe is solved by using soft compliant PTFE and PVC tubes that accommodate thermal deformations of the ceramic tubes during startup and operation. We show the resulting heat exchangers in static tests using argon and helium as propellants