Controlling surface plasmon polaritons in transformed coordinates

Transformational optics allows for a markedly enhanced control of the electromagnetic wave trajectories within metamaterials, with interesting applications ranging from perfect lenses to invisibility cloaks, carpets, concentrators and rotators. Here we present a review of curved anisotropic heterogeneous meta-surfaces designed using the tool of transformational plasmonics, in order to achieve a similar control for surface plasmon polaritons in cylindrical and conical carpets (for the latter we provide some analytical insight), as well as cylindrical cloaks, concentrators and rotators of a non-convex cross-section. Finally, we provide an asymptotic form of the geometric potential for surface plasmon polaritons on such surfaces in the limit of a small curvature.     

Characterisation of Phenolic Compounds in Oils Produced from Frosted Olives

Frost is one of the most important weather related hazards for the Australian olive industry and it has caused significant economic losses during the last decade. Its impact on oil quality was significant in 2006 with more than 20% of Australian oil of that year being affected to some degree. Early frosts will normally affect the fruit leading to significant changes in the chemical and organoleptic characteristics of the oils. The aim of this work was to study the effect of freeze damage on the phenolic composition and quality parameters of oils from three different varieties: Frantoio, Barnea and Picual. Quality chemical parameters showed significant differences in oils produced from fruit that was frozen for 2 and 4 weeks. Those chemical parameters were not significantly different in the oil produced from fruit immediately after being frosted. Nonetheless, the sensorial profile and the polyphenols showed significant changes even with oils produced within a short time after the freezing event. Those changes became more evident with the oils produced at increasing time from the moment of fruit freezing.     

Direct calculation of modal parameters from matrix orthogonal polynomials

The object of this paper is to introduce a new technique to derive the global modal parameter (i.e. system poles) directly from estimated matrix orthogonal polynomials. This contribution generalized the results given in Rolain et al. (1994) [5] and Rolain et al. (1995) [6] for scalar orthogonal polynomials to multivariable (matrix) orthogonal polynomials for multiple input multiple output (MIMO) system.Using orthogonal polynomials improves the numerical properties of the estimation process. However, the derivation of the modal parameters from the orthogonal polynomials is in general ill-conditioned if not handled properly. The transformation of the coefficients from orthogonal polynomials basis to power polynomials basis is known to be an ill-conditioned transformation. In this paper a new approach is proposed to compute the system poles directly from the multivariable orthogonal polynomials. High order models can be used without any numerical problems.The proposed method will be compared with existing methods (Van Der Auweraer and Leuridan (1987) [4] Chen and Xu (2003) [7]). For this comparative study, simulated as well as experimental data will be used.     

Quantification of fire gases by FTIR: Experimental characterisation of calibration systems

Gaseous fire effluents contain a mixture of components, some of which are present in toxicologically significant proportions, together with water vapour and particulate matter, representing a significant challenge to the analyst. The most useful information is obtained from fire gases at about 180 °C where water and most organic species are volatile. Despite this, it is often necessary to sample and measure fire effluents for prediction of fire toxicity, estimation of the environmental impact of fires, and to understand their behaviour.Gas phase Fourier Transform Infrared (FTIR) spectroscopy has the potential to measure almost all volatiles on a continuous basis during fire. This paper considers the key parameters, which must be carefully measured and controlled in order to obtain reliable calibration data. It evaluates a number of techniques designed for calibrating an FTIR spectrometer for use in fire gas analysis with conclusions on the best system for use for each species and for specific fire tests or experimental scenarios.As few molecules in the gas phase infrared spectrum obey the Beer-Lambert law, a full set of infrared spectra at different concentrations must be obtained for each target analyte, for the actual spectrophotometer—gas cell configuration in use. In some cases, stable standard mixtures are available, and these only have to be quantitatively diluted. In other cases reactive gases such as hydrogen halides must be generated quantitatively in situ, or vapours must be generated from volatile liquids under controlled conditions, in order to obtain calibration spectra. In each case, care must be taken in the design of the sampling line and calibration system, paying particular attention to the temperature, pressure and gas flow.Gas phase FTIR is a powerful analytical tool, but requires a significant investment in time and equipment before quantitative analysis can be undertaken. Unless care is taken to ensure constant temperature and pressure in the sample lines and gas cell, significant errors will result.     

3D modeling of uranium-bearing solution-collapse breccias in Proterozoic sandstones (Athabasca Basin,Canada)—Metallogenic interpretations

Unconformity-related uranium deposits are the highest grade, large tonnage uranium resources in the world. In the Athabasca Basin (northern Saskatchewan, Canada), which is the premier host for unconformity-type deposits, the ore deposits are frequently hosted and surrounded by breccias in sandstone. The significance of these breccias and their relation to mineralization are of major importance for the genesis of these high-grade deposits. Therefore, a modeling study, integrating results from structural geology and petrology, was performed with the gOcad 3D modeling software, in order to decipher geometrical and geological relationships between breccias, faults and mineralization zones. Mineralized bodies and the sudoite–dravite breccia bodies display strong spatial correlations. They appear to be controlled by reverse shear zones cross-cutting the unconformity and containing graphite in the basement. Geochemical computations evidenced that volumetric water–rock ratios up to 10,000 could be obtained in these breccia bodies for volume losses of up to 90%. Assuming reasonable values for quartz saturation, hydraulic conductivity and connected porosity, the minimal fluid volume and the time duration necessary to generate the sudoite–dravite breccia bodies were estimated at ca. 2 km³ and ca. 1 Myr, respectively. The comparison of these results with literature data suggests that the formation of sudoite–dravite breccia and mineralization could have been coeval. It may be proposed that within the space created by the quartz dissolution in the breccia body, a mixing between basement and basinal fluids could have induced U deposition and allowed the development of high-grade mineralization. The first-order uranium solubility that this coeval formation would imply is consistent with literature data, which suggests that this conceptual model is reasonable.     

Geometrical analysis of thread milling—part 2: calculation of uncut chip thickness

Thread milling offers interesting possibilities for machining internal or external threads. This machining technique uses a mill with a triangular profile for metric threads and a helical interpolation strategy. Thus, the uncut chip thickness cannot be easily evaluated from a simplified approach. The present study deals with a model for calculating uncut chip thickness during internal thread milling. This step is needed to understand and model the cutting forces. The model developed uses the geometrical definitions of the mill and takes into account the milling mode and the cutting conditions. The link with the interferences between the tool and the thread is also established and corroborates a previous study. A full analytical formulation of the problem is proposed, and results from different milling settings are presented.     

Structure elucidation of three triterpene glycosides from the trunk of Argania spinosa

Drs. John Elce and Peter Davies, biochemists at Queen's University, Kingston, Ont., are investigating the molecular structure of calpain, an enzyme that has been implicated in the cellular damage that occurs after such events as myocardial infarction and stroke. This damage is precipitated by an imbalance in the regulation of calpain that arises as an indirect result of ischemia. Elce and Davies hope that their research, which involves techniques such as recombinant DNA technology and x-ray crystallography, will lead to the development of a calpain inhibitor that will prevent such damage from occurring and enhance recovery.     

Interactive global and local deformations for virtual clay

Making virtual modeling as easy and intuitive as real-clay manipulation is still an unsolved problem. This paper takes a step in this direction: in addition to offering standard features such as addition and removal of material, it uses a new real-time plasticity model to let the user apply local and global deformations such as those made in real clay by pressing with a finger or bending a sculpture with one hand. Although not completely physically accurate, the model exhibits several important features of real clay, namely plasticity, mass conservation, and surface tension effects. These features make the model intuitive, since the user obtains the shapes he expects, as demonstrated by our results.     

Différences individuelles au niveau des croyances erronées à l'égard des inquiétudes.

Erroneous beliefs have been identified as key variables related to the development and maintenance of excessive worry. For example, people presenting a high level of worry often believe that worrying helps them to prevent the occurrence of future negative events or translates a positive characteristic of their personality. They thus develop excessive and uncontrollable worries in order to maintain the perceived advantages. The factors related to the development and the maintenance of erroneous beliefs about worry are however unknown. The aim of this study was to verify the relationship between erroneous beliefs and personal variables (i.e., gender, worry themes, and predominant types of worries) in a sample of 544 participants. Analyses showed that beliefs differed significantly according to the gender, but not according to the predominant types of worries. School concerns were significantly associated with the belief that worry helps to motivate. This study brings preliminary useful information to better understand the presence of erroneous beliefs about worries and suggests conducting further researches using other personal variables and clinical samples. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An on-line combined linear–nonlinear fatigue crack detection technique

To monitor the structural health during fatigue tests, classical nondestructive tests (ultrasonic inspection, liquid penetration, eddy current, etc.) are usually performed at regular time instances. Unfortunately, the fatigue tests should be interrupted to use these techniques. In addition, a large amount of user interaction is required.In this article, vibration features are used to detect cracks on-line with the execution of a fatigue test. To perform this task, an experimental strategy is developed to simultaneously estimate static and dynamic as well as linear and nonlinear vibration features. By means of these features the sensitivity of static versus dynamic and linear versus nonlinear damage detection techniques will be qualified.Finally, it will be shown that by using nonlinear identification techniques, additional information on the damage scenario can be extracted.The validation will be done on a steel beam with a propagating fatigue crack.