Search results for "Instability"
showing 10 items of 724 documents
Effects of supervised slackline training on postural instability, freezing of gait, and falls efficacy in people with Parkinson's disease.
2016
The aim of this study was to assess whether supervised slackline training reduces the risk of falls in people with Parkinson's disease (PD).Twenty-two patients with idiopathic PD were randomized into experimental (EG, N = 11) and control (CG, N = 11) groups. Center of Pressure (CoP), Freezing of Gait (FOG), and Falls Efficacy Scale (FES) were assessed at pre-test, post-test and re-test. Rate perceived exertion (RPE, Borg's 6-20 scale) and local muscle perceived exertion (LRPE) were also assessed at the end of the training sessions.The EG group showed significant improvements in FOG and FES scores from pre-test to post-test. Both decreased at re-test, though they did not return to pre-test l…
A new scenario for banks: glocal banking. A theoretical approach to propose for Europe
2017
In the early 1990s, with the development of information and communication technology (ICT), global banks began looking for a new world consisting of markets rather than relationships through the development of standardised services in the markets. However, in the early 21st century, with the collapse of the speculative bubble and the financial crisis of 2008, which caused financial instability and damaged the real economy, the entire banking system and the market itself suffered profound changes in profitability. Thus, began efforts to develop a new cultural relationship between banks and companies known as 'glocal banking'. These include: studying the needs of customers, planning and provi…
Compressive behavior of FRP externally wrapped R.C. column with buckling effects of longitudinal bars
2018
Abstract In this paper, a calculation model to simulate the compressive behavior of R.C. columns with square cross-sections externally wrapped with FRP, including buckling effects of the longitudinal bars and reduction of the confinement pressure induced by the buckled compressed bars, is presented and discussed. The model distinguishes the cases of corner and side bars, calculating the different critical lengths and the critical loads. The Teng et al. (2009) model was adopted to predict the compressive behavior of FRP-confined concrete, and the Dhakal and Maekawa (2002) model was taken into account to predict the compressive behavior of longitudinal bars. The critical length and critical s…
Unveiled the Source of the Structural Instability of HKUST-1 Powders upon Mechanical Compaction: Definition of a Fully Preserving Tableting Method
2018
Metal–organic frameworks (MOFs) are getting closer to finally being used in commercial applications. In order to maximize their packing density, mechanical strength, stability in reactive environme...
Unusual Magnetic State in Lithium-DopedMoS2Nanotubes
2003
We report on the very peculiar magnetic properties of an ensemble of very weakly coupled lithium-doped MoS2 nanotubes. The magnetic susceptibility chi of the system is nearly 3 orders of magnitude greater than in typical Pauli metals, yet there is no evidence for any instability which would alleviate this highly frustrated state. Instead, the material exhibits peculiar paramagnetic stability down to very low temperatures, with no evidence of a quantum critical point as T-->0 in spite of clear evidence for strongly correlated electron behavior. The exceptionally weak intertube interactions appear to lead to a realization of a near-ideal one-dimensional state in which fluctuations prevent the…
PEDOT thin films with n-type thermopower
2019
peer-reviewed Synthesis of n-type organic semiconductors is challenging as reduced states are difficult to obtain due to their instability in air. Here, we report tailoring of semiconducting behavior through control of surfactant concentration during synthesis of poly(3,4-ethylenedioxythiophene) (PEDOT) nanoparticles. Nanoparticles were synthesized by mini-emulsion polymerization, where stable suspensions were used to produce polymer films by a simple casting technique on polyethylene terephthalate (PET) substrates. Electrical conductivity and Seebeck coefficients were measured as a function of surfactant concentration. It was found that conductivity decreases three orders of magnitude as s…
Hygroexpansivity of anisotropic sheets
2015
Dimensional instability, more particularly its component hygroexpansivity, may cause problems in process or end-use situations in which paper or board is in contact with water or subject to changes in ambient relative humidity. Misregistration in printing, curl during copying and calender wrinkles are examples of such defects. In this paper, the in-plane hygroexpansivity of oriented laboratory sheets with different pulps and dried both freely and under restraint is studied. A linear relationship between the drying shrinkage and hygroexpansion coefficient of freely dried laboratory sheets having different fiber orientation anisotropies, was observed. Regardless of both the measurement direct…
Labyrinthine instability of miscible magnetic fluids
2002
Abstract We consider an inhomogeneous magnetic fluid (MF), modeling a miscible MF pair, in a Hele–Shaw cell under a normal field. A linear stability analysis for the sharp straight interface (analytically) and for the diffused one (numerically) is performed. For the former case, the neutral curves and the stability diagram are found along with the critical wavelength and parameter values. Oscillatory or monotonous instabilities are shown to occur. For the diffused interface, we recognize the importance of 2D flow viscous effects along with the conventional wall friction and observe that in strong fields the dominant wavelength scales as the cell gap.
Oil-in-Water fL Droplets by Interfacial Spontaneous Fragmentation and Their Electrical Characterization
2019
Inkjet printing is here employed for the first time as a method to produce femtoliter-scale oil droplets dispersed in water. In particular, picoliter-scale fluorinated oil (FC40) droplets are printed in the presence of perfluoro-1-octanol surfactant at a velocity higher than 5 m/s. Femtoliter-scale oil droplets in water are spontaneously formed through a fragmentation process at the water/air interface using minute amounts of nonionic surfactant (down to 0.003% v/v of Tween 80). This fragmentation occurs by a Plateau-Rayleigh mechanism at a moderately high Weber number (10(1)). A microfluidic chip with integrated microelectrodes allows droplets characterization in terms of number and diamet…
A phase-field model for strain localization analysis in softening elastoplastic materials
2019
Abstract The present paper deals with the localization of strains in those structures consisting of materials exhibiting plastic softening response. It is assumed that strain localization develops in a finite thickness band separated from the remaining part of the structure by weak discontinuity surfaces. In view of the small thickness of the band with respect to the dimensions of the structure, the interphase concept is used for the mechanical modeling of the localization phenomenon. We propose a formulation for the quasi-static modeling of strain localization based on a phase-field approach. In this sense, the localization band is smeared over the volume of the structure and a smooth tran…