Search results for "stiffness"
showing 10 items of 524 documents
Retrofitting of Existing Steel MR-Frames by Encasing the Columns
2005
Summary The study concerns the behaviour of steel MR-frames subjected to vertical and lateral forces, not properly designed according to capacity design criteria, and upgraded by means of encasing the steel columns with concrete having different grade. The purpose of the paper is to examine if the proposed technique allows one to adequately increase the lateral stiffness and the resistance of the frames. Pushover analyses on multi-storey frames are performed trough a non-linear calculus program, able to take into account of the second order effects. The behaviour of frames with encased columns was compared with those of the bare frames, highlighting that with the proposed technique it is po…
Computer simulation studies of finite-size broadening of solid–liquid interfaces: from hard spheres to nickel
2009
Using Molecular Dynamics (MD) and Monte Carlo (MC) simulations interfacial properties of crystal-fluid interfaces are investigated for the hard sphere system and the one-component metallic system Ni (the latter modeled by a potential of the embedded atom type). Different local order parameters are considered to obtain order parameter profiles for systems where the crystal phase is in coexistence with the fluid phase, separated by interfaces with (100) orientation of the crystal. From these profiles, the mean-squared interfacial width w^2 is extracted as a function of system size. We rationalize the prediction of capillary wave theory that w^2 diverges logarithmically with the lateral size o…
Haemodynamics of primary aldosteronism associated with adrenocortical adenoma: insights from bioimpedance cardiography measurements
2020
In mid 1950s, Dr Jerome Conn described a patient with hypertension, and renal potassium wasting associated with adrenocortical adenoma and increased urinary excretion of a sodium-retaining hormone, initially termed electrocortin, which was subsequently shown to be aldosterone. This was the first full report of primary hyperaldosteronism associated with an aldosterone-producing adenoma (APA). It subsequently became apparent that similar abnormalities can occur in the absence of an adrenocortical tumor, and it is now recognized that the APA is just one of many subtypes of primary aldosteronism (PA).
Relationship Between Carotid Atherosclerosis and Pulse Pressure with Renal Hemodynamics in Hypertensive Patients.
2015
BACKGROUND Structural atherosclerotic damage, arterial stiffness, pulse pressure (PP), and renal hemodynamics may interact and influence each other. Renal resistance index (RRI) appears as a good indicator of systemic vascular changes. The aim of our study was to assess the independent relationships of carotid intima-media thickness (cIMT), aortic pulse wave velocity (aPWV), and peripheral PP with RRI in hypertensives with various degrees of renal function. METHODS We enrolled 463 hypertensive patients (30-70 years) with normal renal function (group 0; n = 280) and with chronic kidney disease (groups I-V; n = 183). All subjects underwent ultrasonographic examination of intrarenal and caroti…
Early Vascular Aging in Normotensive Patients With Systemic Lupus Erythematosus
2015
Connective tissue diseases, like systemic lupus erythematosus (SLE), are associated with early and accelerated atherosclerosis. Recently, the concept of “early vascular aging” (EVA) has been more widely accepted. Aortic stiffness is one of the important markers of EVA. We evaluated EVA and subclinical atherosclerosis, by measuring aortic pulse wave velocity (aPWV) and carotid intima–media thickness (cIMT), in 50 normotensive patients with SLE (mean age: 39 ± 12 years). We compared these participants with 50 age- and sex-matched patients with essential hypertension (EH) and 20 healthy controls. Each participant underwent 24-hour ambulatory blood pressure monitoring (ABPM), aPWV, and cIMT me…
A nonhomogeneous nonlocal elasticity model
2006
Nonlocal elasticity with nonhomogeneous elastic moduli and internal length is addressed within a thermodynamic framework suitable to cope with continuum nonlocality. The Clausius–Duhem inequality, enriched by the energy residual, is used to derive the state equations and all other thermodynamic restrictions upon the constitutive equations. A phenomenological nonhomogeneous nonlocal (strain difference-dependent) elasticity model is proposed, in which the stress is the sum of two contributions, local and nonlocal, respectively governed by the standard elastic moduli tensor and the (symmetric positive-definite) nonlocal stiffness tensor. The inhomogeneities of the elastic moduli and of the int…
Experimental Investigation on Water Loss and Stiffness of CBTM Using Different RA Sources
2021
Cold recycling of reclaimed asphalt (RA) is a promising technique to build or to maintain roads, combining performance and environmental advantages. Although this technique has been extensively used worldwide, there is no unique and internationally-shared method to characterize cold recycled mixtures. The previous work of the RILEM TC 237-SIB TG6 successfully attempted to characterize different RA sources with both traditional parameters (gradation, bitumen content and geometrical properties) and non-conventional properties (fragmentation and strength testing). The current RILEM TC 264-RAP TG1 mainly focuses on the influence of different RA sources on physical and mechanical characteristics…
Effects of self-myofascial release: A systematic review.
2015
Summary Background Self-myofascial release (SMFR) is a type of myofascial release performed by the individual themselves rather than by a clinician, typically using a tool. Objectives To review the literature regarding studies exploring acute and chronic clinical effects of SMFR. Methods PubMed and Google Scholar databases were searched during February 2015 for studies containing words related to the topic of SMFR. Results Acutely, SMFR seems to increase flexibility and reduce muscle soreness but does not impede athletic performance. It may lead to improved arterial function, improved vascular endothelial function, and increased parasympathetic nervous system activity acutely, which could b…
Optimal design of flax fiber reinforced polymer composite as a lightweight component for automobiles from a life cycle assessment perspective
2019
The present study combines the generalized rule-of-mixture (ROM) model and the Ashby material selection method for the life cycle assessment (LCA) of flax fiber reinforced polymers (FRPs) and glass FRPs (GFRPs). The ROM model allows life cycle environmental impact predictions according to specific parameters of flax FRPs such as fiber format, volume fraction, manufacturing technique, and load-bearing capacity. The comparisons applied in this study are constructed on two common composite structures: mat panels and injection molded struts with equal stiffness and strength as the design criteria. On the one hand, the parametric LCA predicts that the equal strength design criterion for flax FRP…
Some comments on the experimental behavior of FRC beams in flexure
2008
In the present paper the experimental results, recently obtained by the authors, regarding the monotonic and the cyclic flexural response of normal and high-strength concrete beams reinforced with steel bars and discontinuous fibers, are shown. From the experimental results, all referred to low values of shear-to-depth ratios, it emerges clearly that the shear failure is brittle especially under cyclic actions highlighting the role of the fibers in the flexural behavior of the beams. The cyclic action produces a significant decay in the stiffness and in the strength capacity of the beams, and the addition of fibers reduces these negative effects. Form theoretical point of view good agreemen…