Search results for "DEFORMATION"
showing 10 items of 515 documents
Bis(dimethylammonium) pentachloroantimonate(III), on the deformation of the octahedral coordination of Sb III
1998
The structure of the title compound, [NH2(CH3)2]2SbCl5, was determined at 295 and 85 K. It consists of polymeric (SbCl52−)n chains composed of deformed SbCl63− octahedra connected by corners and dimethylammonium cations. The temperature dependence of the Sb–Cl bond lengths is discussed. It is argued that the deformation of the octahedral coordination of the SbIII atom is caused by electrostatic interaction/hydrogen bonds.
Simplified technique for constitutive analysis of SFRC
2014
Steel fibre reinforced concrete (SFRC) has become widespread material in areas such as underground shotcrete structures and industrial floors. However, due to the absence of material models of SFRC reliable for numerical analysis, application fields of this material are still limited. Due to interaction of concrete with fibres, a cracked section is able to carry a significant portion of tensile stresses, called the residual stresses. In present practices, residual stresses used for strength, deflection and crack width analysis are quantified by means of standard tests. However, interpretation of these test results is based on approximation using empirically deduced relationships, adequacy o…
On the hyperporous non-linear elasticity model for fusion-relevant pebble beds
2010
Abstract Packed pebble beds are particular granular systems composed of a large amount of small particles, arranged in irregular lattices and surrounded by a gas filling interstitial spaces. Due to their heterogeneous structure, pebble beds have non-linear and strongly coupled thermal and mechanical behaviours whose constitutive models seem limited, being not suitable for fusion-relevant design-oriented applications. Within the framework of the modelling activities promoted for the lithiated ceramics and beryllium pebble beds foreseen in the Helium-Cooled Pebble Bed breeding blanket concept of DEMO, at the Department of Nuclear Engineering of the University of Palermo (DIN) a thermo-mechani…
Data Compression Approach for Long-Term Monitoring of Pavement Structures
2019
Pavement structures are designed to withstand continuous damage during their design life. Damage starts as soon as the pavement is open to traffic and increases with time. If maintenance activities are not considered in the initial design or considered but not applied during the service life, damage will grow to a point where rehabilitation may be the only and most expensive option left. In order to monitor the evolution of damage and its severity in pavement structures, a novel data compression approach based on cumulative measurements from a piezoelectric sensor is presented in this paper. Specifically, the piezoelectric sensor uses a thin film of polyvinylidene fluoride to sense the ener…
(no title)
1999
We propose hereafter that the signature of the Space-Time metric (+++-) is not anymore frozen at the Planck scale and presents quantum fluctuations (+++±) untill 0 scale where it becomes Euclidean (++++). (i) At the albraic level we suggest an oscillation path (3,1) (4,0) exluding (2,2). We built the quotient topological space describing the superposition of the Lorentzian and the Riemanian metrics. In terms of quantum groups we evidence a relation between q-deformation and deformation of the signature. We have obtained a new algebraic construction ( a new cocycle bicross products by twisting) which allowed us to unify the Lorentzian and the Euclidean signatures within a unique quantum grou…
Early detection of myocardial damage: A multimodality approach
2019
Cardiovascular diseases are possible complications of antineoplastic treatment and may lead to premature morbidity and mortality among cancer survivors. A symptom-based follow-up is ineffective, and there are growing evidences that early detection of myocardial damage in patients treated with antineoplastic drugs is the key point to prevent the occurrence of damage and improve the prognosis of these patients. Different techniques have been proposed to monitor cardiac function in oncologic patients such as cardiac imaging (echocardiography, nuclear imaging, and cardiac magnetic resonance) and biomarkers (troponin and natriuretic peptides). The European Association of Cardiovascular Imaging/A…
Dynamic mode rheology of cement and tricalcium silicate pastes from mixing to setting
2001
Dynamic mode rheometry was used to study the evolution of the structure of cement and pure tricalcium silicate pastes from mixing up to setting and even after setting, together with the nature of the forces responsible for the mechanical properties of the pastes. A special mixer-type tool was used to study rheology during the very first minutes following the end of mixing, which are out of reach with classical tools. Both kinds of pastes have the same behavior. It was found that the main evolution of the structure of the pastes occurs during the very first minutes following the end of mixing, while there is no change in interparticular forces up to setting and even a few hours later. Settin…
Microstructure and mechanical effects of spark plasma sintering in alumina monolithic ceramics
2013
The specific effects of spark plasma sintering (SPS) on the creep behavior, microstructure and mechanical properties of alumina monolithic ceramic were investigated. SPS introduces strains that concentrate at grain boundaries and inhibit crack growth, resulting in an improvement in the flexural strength and fracture toughness. However, creep blocks grain boundary movements and decreases the reliability of the material. These strains can be removed by a post-sintering thermal treatment, which plays an important role in the distribution of dislocations.
On deformation of Poisson manifolds of hydrodynamic type
2001
We study a class of deformations of infinite-dimensional Poisson manifolds of hydrodynamic type which are of interest in the theory of Frobenius manifolds. We prove two results. First, we show that the second cohomology group of these manifolds, in the Poisson-Lichnerowicz cohomology, is ``essentially'' trivial. Then, we prove a conjecture of B. Dubrovin about the triviality of homogeneous formal deformations of the above manifolds.
Invariant deformation theory of affine schemes with reductive group action
2015
We develop an invariant deformation theory, in a form accessible to practice, for affine schemes $W$ equipped with an action of a reductive algebraic group $G$. Given the defining equations of a $G$-invariant subscheme $X \subset W$, we device an algorithm to compute the universal deformation of $X$ in terms of generators and relations up to a given order. In many situations, our algorithm even computes an algebraization of the universal deformation. As an application, we determine new families of examples of the invariant Hilbert scheme of Alexeev and Brion, where $G$ is a classical group acting on a classical representation, and describe their singularities.