A MICRO-MACRO MODEL FOR THE EFFECTS OF THERMO-MECHANICAL FIELDS ON OPTICAL FIBRES EMBEDDED IN A LAMINATED COMPOSITE PLATE WITH APPLICATIONS TO SENSING

SUMMARY

A coupled micro-macromechanical approach is employed to model an optical fibre in a reinforced composite. As a result, the opto-thermo-mechanical behaviour of the optical fibre is determined in such a way that the phase-strain relationship is based on the micromechanical behaviour of the host media. The microstructures of the carbon fibre reinforced composite and the optical fibre inclusion are analysed, and their mutual influence on the performance of the entire composite structure is estimated. Different cases of laminated composite plates subjected to several cases of external loadings and temperature fields are studied. In-plane strains at the optical fibre, as well as in the composite are presented. The results are also applied to the study of embedded Fabry-Perot and radio-frequency fibre-optic strain and temperature sensors.     

A stand‐alone compact EUV microscope based on gas‐puff target source

We report on a very compact desk‐top transmission extreme ultraviolet (EUV) microscope based on a laser‐plasma source with a double stream gas‐puff target, capable of acquiring magnified images of objects with a spatial (half‐pitch) resolution of sub‐50 nm. A multilayer ellipsoidal condenser is used to focus and spectrally narrow the radiation from the plasma, producing a quasi‐monochromatic EUV radiation (λ = 13.8 nm) illuminating the object, whereas a Fresnel zone plate objective forms the image. Design details, development, characterization and optimization of the EUV source and the microscope are described and discussed. Test object and other samples were imaged to demonstrate superior resolution compared to visible light microscopy.     

The effect of smoking on skin moisture and on surface lipids

In the present retrospective study we investigated the effect of smoking on the moisture and surface lipid levels of the skin. We analysed data from the files of 576 female clients treated in a Tel-Aviv cosmetic parlour. Measurements have been conducted by the same cosmetician, by commercially available equipment, on every client receiving cosmetic treatment, regardless of the nature of the treatment.
Results demonstrated a significant difference of skin moisture in the various smoking groups: women who smoked 11–20 cigarettes per day showed significantly lower mean values than the non-smoker group, as expected. Moreover, women before or after menopause showed no significant differences in their moisture measurements.
The surface lipid variables showed no significant differences in mean over the four smoking groups.
We believe that the objective of the study was achieved, and that the results, indicating decreased skin moisture in smokers, will serve well in anti-smoking campaigns. We also believe that the present study will stimulate other investigators to conduct similar studies that will provide answers to the many questions which still remain open.     

Extraction of the generalized stress intensity factor in gross sliding complete contacts using a path‐independent integral*

A new procedure to extract the generalized stress intensity factor (GSIF) in full sliding complete contact problems is proposed. It is based on a path‐independent integral derived from the reciprocal theorem of Maxwell‐Betti and on a specially conceived extraction field. This extraction field avoids the computation of path integrals along the contact plane that start from the singular point. The methodology presented here is also applicable to configurations with large relative displacements of the indenter (gross sliding). The procedure overcomes the problems that arise when extracting the GSIF via the stress extrapolation technique, because it does not need highly refined meshes, and it can be applied far from the singularity‐dominated zone and with much less user intervention. The robustness of the method has been verified with numerical examples, studying the effect of large displacements of the indenter and different discretizations.