Search results for "wall"
showing 10 items of 970 documents
Über die kinetik und den mechanismus der biosynthese der cellulose in den höheren pflanzen (nach versuchen an den samenhaaren der baumwolle)
1966
Abstract The quantity of cellulose synthesized on growing cotton bolls and the corresponding degree of polymerisation have been measured as a function of time. It was found that the biosynthesis proceeds in two distinct stages, beginning with a slow process yielding the “primary” cellulose with a non-uniform degree of polymerisation of about 2000–6000 followed by a more rapid process yielding a large amount of “secondary cellulose” with a high and uniform degree of polymerisation of about 14000 (mol. wt. 2.3·106). During the second stage the degree of polymerisation is independent of time. It is shown that the two kinds of cellulose correspond to the primary and secondary cell wall. In orde…
Neuere untersuchungen über größe und größenverteilung der β-glukosidischen ketten nativer cellulosen
1963
Der Polymerisationsgrad Pw der β-glukosidischen Ketten der Cellulose in unbehandelten Baumwollen verschiedener Herkunft liegt etwa zwischen 8500 und 9500. Die Molekulargewichtsverteilung zeigt 3 ausgepragte Maxima beim Polymerisationsgrad 11 500, 5500 und ca. 1500. Das letztere Maximum gehort wahrscheinlich zum Cellulosematerial der Primarwand, wahrend die beiden anderen Maxima dem Material der Sekundarwand angehoren. Die hohe Einheitlichkeit und der grose Mengenanteil des zum hochsten Maximum (bei P = 11 500) gehorenden Celluloseanteils legt es nahe, fur die biochemische Synthese der Cellulose einen POISSONmechanismus oder einen Matritzenmechanismus anzunehmen. Fasercellulosen aus anderen …
Πλησίον τοῦ τείχους. Aree di culto rupestri e ‘vie sacre’ presso le mura nella Sicilia di età classica ed ellenistica
2020
The niches hewn in the rock in proximity to city gates and-walls are a recurring trait of the peri-urban landscape of Sicilian towns, especially in the south-eastern part of the island. Niches are pierced too, in multiple rows, on the walls of former quarries, in most cases close to the city walls, or in artificial caves used for cultic purposes, as inscriptions and traces of offerings testify. The excavations of Paolo Orsi in the latomie of Syracuse and Acre, in the rock or cave sanctuaries of Noto and Acre itself, and in the upper terrace of the theatre of Syracuse, suggested the main recipients of such worship were some “minor” deities like the Nymphs, the Muses or the Paides, and above …
Conducting sensory analysis tests among the elderly
2015
Extracellular matrix fiber microarchitecture is region-specific in bicuspid aortic valve-associated ascending aortopathy
2016
Abstract Objective Ascending thoracic aortic aneurysm (ATAA) in patients with bicuspid aortic valve (BAV) commonly dilate asymmetrically compared with patients with tricuspid aortic valve (TAV). This discrepancy in aneurysm geometry led us to hypothesize that microarchitectural differences underlie the observed asymmetric dilatation pattern. The purpose of this study was to characterize the microarchitectural distinctions of the extracellular matrix of the 2 phenotypes with a focus on the proportion of radially oriented elastin and collagen fibers in different circumferential aortic regions. Methods Aortic tissue rings were obtained just distal to the sinotubular junction from patients with…
Imaging Spin Dynamics on the Nanoscale Using X-Ray Microscopy
2015
The dynamics of emergent magnetic quasiparticles, such as vortices, domain walls and bubbles are studied by scanning transmission X-ray microscopy (STXM), combining magnetic (XMCD) contrast with about 25 nm lateral resolution as well as 70 ps time resolution. Essential progress in the understanding of magnetic vortex dynamics is achieved by vortex core reversal observed by sub-GHz excitation of the vortex gyromode, either by ac magnetic fields or spin transfer torque. The basic switching scheme for this vortex core reversal is the generation of a vortex-antivortex pair. Much faster vortex core reversal is obtained by exciting azimuthal spin wave modes with (multi-GHz) rotating magnetic fiel…
Effective charge from lattice QCD
2020
Using lattice configurations for quantum chromodynamics (QCD) generated with three domain-wall fermions at a physical pion mass, we obtain a parameter-free prediction of QCD's renormalisation-group-invariant process-independent effective charge, $\hat\alpha(k^2)$. Owing to the dynamical breaking of scale invariance, evident in the emergence of a gluon mass-scale, this coupling saturates at infrared momenta: $\hat\alpha(0)/\pi=0.97(4)$. Amongst other things: $\hat\alpha(k^2)$ is almost identical to the process-dependent (PD) effective charge defined via the Bjorken sum rule; and also that PD charge which, employed in the one-loop evolution equations, delivers agreement between pion parton di…
Divided Wall Column Modeling and Simulation in an Open-Source Environment
2020
The divided wall column (DWC) can achieve sharp separations of three or more components in a single shell, substituting conventional sequences of two or more binary distillation columns, with lower expenses. Despite these advantages, DWC models are not available in commercial chemical process simulators. To simulate DWC, users must employ instances of conventional column model and couple them in different configurations. In this paper, a DWC model was developed in EMSO (Environment for Modeling, Simulation and Optimization). DWC model was then used for simulating the separation of an equimolar mixture of three hydrocarbons. Results show that, depending on the number of trays, DWC presented …
Study of tin and gold halos in the medieval wall painting depicting Saints Luke the Evangelist and Gregory the Great in Palermo’s San Francesco d’Ass…
2022
Lo scopo di questo studio è quello di fornire un supporto al restauratore quando si trova ad affrontare un manufatto con doratura a foglia di stagno. Lo studio dei materiali originali ha fornito un quadro completo dei vari componenti coinvolti, organici e inorganici, e sono stati delineati i degradi più comuni, nonché i metodi di conservazione per questi materiali estremamente fragili e sensibili come le foglie metalliche The purpose of this study is to provide a support for the restorer when facing an artifact with tin leaf gilding. The study of the original materials gave a complete picture of the various components involved, organic and inorganic, and the most common degradations were ou…
La costruzione del paesaggio ibleo: reti deboli, segni forti
2017
The contribution deals with the theme of the dry stone walls’ landscape which characterizes the rural “Koinè” of the Hyblean plateau in South-Eastern Sicily. The essay analyses the main political-economic, social-territorial, constructive and typological features which make the dry walls network the landmark of the Ragusa province. Because of the modification of the economic-cultural context that produced it, the loss of knowledge of the construction techniques and the lack of public resources, the definition of an axiology of the contemporary landscape as premise for the establishment of adequate terms of value for the safeguard of this heritage is required.