Search results for "position"
showing 10 items of 6771 documents
2D size, position and shape definition of defects by B-scan image analysis
2015
The non-destructive evaluation of defects by automatic procedures is of great importance for structural components. Thanks to the developments of the non-contact ultrasonic techniques, the automation of the inspections is gaining a progressively important role. In this work, an automatic inspection technique for the evaluation of defects by the analysis of B-scan images obtained by a laser ultrasonic system is presented. The data are extracted directly from a B-scan map obtained for a panel with internal defects, and are used to build an image of the cross section of the panel. The proposed automatic procedure allows the definition of size, position and shape of defects in panels of known t…
Mapping an electron wave function by a local electron scattering probe
2015
A technique is developed which allows for the detailed mapping of the electronic wave function in two-dimensional electron gases with low-temperature mobilities up to $15\times {10}^{6}\;{\mathrm{cm}}^{2}\;{{\rm{V}}}^{-1}\;{{\rm{s}}}^{-1}$. Thin ('delta') layers of aluminium are placed into the regions where the electrons reside. This causes electron scattering which depends very locally on the amplitude of the electron wave function at the position of the Al δ-layer. By changing the distance of this layer from the interface we map the shape of the wave function perpendicular to the interface. Despite having a profound effect on the electron mobiliy, the δ-layers do not cause a widening of …
Extra-virgin olive oils storage: Effect on constituents of biological significance
2021
Abstract The high oxidative stability of virgin olive oil with respect to other vegetable oils is mainly due to its fatty acid composition, in particular, to the high monounsaturated-to-polyunsaturated ratio, and to the presence of minor compounds that play a major role in preventing oxidation. In spite of its high stability, virgin olive oil is susceptible to oxidative processes, such as enzymatic oxidation, photooxidation, and autoxidation, which mainly occur during processing and storage. Generally, extra-virgin olive oil has a relatively long shelf life of 16–18 months of storage at room temperature. The study of shelf life is generally based on determining of quality parameters (acidit…
Dehn surgeries and smooth structures on 3-dimensional transitive Anosov flows.
2020
The present thesis is about Dehn surgeries and smooth structures associated with transitive Anosov flows in dimension three. Anosov flows constitute a very important class of dynamical systems, because of its persistent chaotic behaviour, as well as for its rich interaction with the topology of the ambient space. Even if a lot is known about the dynamical and ergodic properties of these systems, there is not a clear understanding about how to classify its different orbital equivalence classes. Until now, the biggest progress has been done in dimension three, where there is a family of techniques intended for the construction of Anosov flows called surgeries.During the realization of this th…
The chemical composition of the aerial parts essential oil of Lonas annua (L.) Vines & Druce (Asteraceae)
2022
Lonas annua (L.) Vines & Druce (Asteraceae), commonly known as African Daisy or Yellow Ageratum is a rare therophyte native to northwestern Africa (Algeria, Morocco, and Tunisia) and Italy (Sicily and Sardinia). In the present study, the chemical composition of the essential oil from aerial parts of Lonas annua was analyzed by GC-MS. No one report has been previously published on the essential oil of this species. The results showed the presence of large quantity of two unusual metabolites 2,3-dihydrofarnesol (41.64%), and acenaphthene (36.18%). Chemotaxonomic considerations were carried out in order to confirm the phylogenetic reconstructions of Anthemideae.
Body Composition in Late Midlife as a Predictor of Accelerated Age-associated Deficit-accumulation From Late Midlife into Old Age: A Longitudinal Bir…
2022
Abstract Background Body mass index (BMI) may not be an optimal predictor of frailty as its constituents, lean and fat mass, may have opposite associations with frailty. Methods A linear mixed model analysis was performed in the Helsinki Birth Cohort Study (n = 2 000) spanning from 57 to 84 years. A 39-item frailty index (FI) was calculated on three occasions over 17 years. Body composition in late midlife included BMI, percent body fat (%BF), waist-to-hip ratio (WHR), lean mass index (LMI), and fat mass index (FMI). Results Mean FI levels increased by 0.28%/year among men and by 0.34%/year among women. Among women, per each kg/m2 higher BMI and each unit higher %BF the increases in FI leve…
El uso de GPS para el análisis del comportamiento espacio-temporal de los turistas. Pre-test en el Valle de Boí
2015
Este artículo es un análisis exploratorio sobre el uso de los GPS para estudiar el comportamiento de los visitantes en un espacio abierto. El Valle de Boí es un escenario turístico que ofrece diversos recursos de primer orden, por lo que el estudio de los recorridos de los visitantes permite analizar la respuesta a estímulos muy diferentes. Los resultados demuestran que el recurso del GPS en espacios abiertos permite ampliar la información sobre el uso social del espacio turístico y abre las puertas a nuevas formas de análisis. This article is an exploratory analysis of the use of GPS for the study of visitors’ behaviour in an open space. The Boi Valley is an open space that offers importan…
Quality Control in 3D Printing: Accuracy Analysis of 3D-Printed Models of Patient-Specific Anatomy
2021
As comparative data on the precision of 3D-printed anatomical models are sparse, the aim of this study was to evaluate the accuracy of 3D-printed models of vascular anatomy generated by two commonly used printing technologies. Thirty-five 3D models of large (aortic, wall thickness of 2 mm, n = 30) and small (coronary, wall thickness of 1.25 mm, n = 5) vessels printed with fused deposition modeling (FDM) (rigid, n = 20) and PolyJet (flexible, n = 15) technology were subjected to high-resolution CT scans. From the resulting DICOM (Digital Imaging and Communications in Medicine) dataset, an STL file was generated and wall thickness as well as surface congruency were compared with the original …
Family background and problems at school and in society: The role of family composition, emotional atmosphere and parental education
1997
Three studies were carried out to examine the extent to which family composition, size and atmosphere, parental control, and the level of parental education and socioeconomic status, are associated with young people’s problems at school, and later on in society. In study 1, twenty-four 13- to 14-year-old underachievers, and 24 of their matched-pair controls, and 24 overachievers and 24 of their matchedpair controls, were compared according to their family background. In study 2, sixteen low achieving pupils, 20 vocational school pupils and 21 senior high school pupils, aged between 14 and 19, were examined. In study 3, twenty unemployed young adults, 14 students with health problems, and 23…
Präpositionale Wortgruppen im Altspanischen: 13.-15. Jahrhundert
2013
Der Untersuchungsgegenstand dieser Dissertation sind präpositionale Wortgruppen (PWG) (locuciones prepositivas) in kastilischen Texten aus dem Mittelalter. Ziel dieser Arbeit ist eine kontrastive Analyse von PWG an Hand von zwei Diskurstraditionen, einer juristischen und einer historischen, während des 13., 14. und 15.Jahrhunderts. Das Hauptkorpus beinhaltet zu jedem Jahrhundert einen juristischen und einen chronistischen Text. Um der Gefahr der einseitigen Konzentration auf juristische und chronistische Texte zu entgehen, werden für jedes Jahrhundert ein zusätzlicher Text aus der Gattung der Literatur ausgewertet (Calila e Dimna, El Conde Lucanor und La Celestina). Ausgangspunkt dieser Arb…