Search results for "Stability"

Competition between chain scission and branching formation in the processing of high-density polyethylene: effect of processing parameters and of sta…

2009

Two samples of high-density polyethylene with different molecular weight were processed in a batch mixer and the rheological and structural properties were investigated. In particular, the effect of different processing parameters and the eventual presence of different stabilizers were evaluated. Actually, two reactions may occur during processing: branching/crosslinking or chain scission. The results indicate that when the processing conditions promote a scarce mobility of the macromolecular chains (lower temperatures, lower mixing speed, and higher molecular weight), branching is more favored than chain scission. On increasing the mobility of the chain (higher temperature, higher mixing s…

Struttura galleggiante ad elevata stabilità (Floating structure with high stability)

2015

DESCRIZIONE GENERALE La struttura galleggiante innovativa è composta da diversi elementi modulari collegati fra loro. La composizione modulare della struttura consente di conferirle la lunghezza dettata dalle particolari esigenze da soddisfare. Tipiche applicazioni della struttura galleggiate innovativa sono i pontili, le passerelle pedonali o ciclabili su specchi d'acqua, e in generale le opere finalizzate a consentire lo spostamento di persone, merci e/o veicoli fra punti di uno specchio d'acqua (marino o lacustre) utilizzando strutture galleggianti. Ogni modulo, lungo 10-15 m, è tenuto a galla dalla spinta di Archimede sulle sue parti immerse (le carene), spinta che nella struttura innov…

In vitro evaluation of the influence of bone cortical thickness on the primary stability of conventional- and short-sized implants

2022

Made available in DSpace on 2022-04-28T19:50:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-01-01 Background: The aim of this in vitro study was to evaluate the influence of the cortical thickness on the primary stability of short and conventional-sized implants with two types of prosthetic connection. Material and Methods: Seventy-two implants were used. These implants were placed in polyurethane blocks that simulated low-density bone tissue (type IV bone), with two bone cortical heights (type I bone): 1mm and 3mm. The implants were divided into 6 groups with 12 implants each according to the type of prosthetic connections (external-hexagon -EH and morse taper- MT) and implant s…

Controversies in ameloblastoma management: Evaluation of decision making, based on a retrospective analysis

2020

Background The ameloblastoma management is still challenging to the high recurrence rates and significant morbidity associated with radical treatment. The purpose of this 10-year retrospective study was to analyze the influence of ameloblastoma type and treatment strategy on the long-term outcomes and recurrence rates. Material and Methods The retrospective analyses of 64 histologically-confirmed ameloblastoma cases was performed. The possible risk factors for recurrence and the development of complications were estimated statistically. Results The treatment strategy applied for this group of patients was the following: thirty-four patients (53.1%) were treated conservatively with enucleati…

PROPAGATING INTERFACES IN A TWO-LAYER BISTABLE NEURAL NETWORK

2006

The dynamics of propagating interfaces in a bistable neural network is investigated. We consider the network composed of two coupled 1D lattices and assume that they interact in a local spatial point (pin contact). The network unit is modeled by the FitzHugh–Nagumo-like system in a bistable oscillator mode. The interfaces describe the transition of the network units from the rest (unexcited) state to the excited state where each unit exhibits periodic sequences of excitation pulses or action potentials. We show how the localized inter-layer interaction provides an "excitatory" or "inhibitory" action to the oscillatory activity. In particular, we describe the interface propagation failure a…

Analiza D-stabilności protokołu TCP-DCR

2012

Praca zawiera analizę stabilności sieci na podstawie protokołu TCP-DCR, będącego modyfikacją tradycyjnego TCP. Utworzono model matematyczny sieci i opisano go równaniami. Schemat blokowy modelu sieci przekształcono do takiej postaci, aby zbadać jego D-stabilność stosując metodę przestrzeni niepewnych parametrów.

Work engagement : psychometrical, psychosocial, and psychophysiological approach

2013

Rayleigh-instability-driven dewetting of thin Au and Ag films on indium-tin-oxide surface under nanosecond laser irradiations

2013

Investigations have been carried out on laser-beam-induced nanoparticle (NP) formation in thin (5 nm) Au and Ag films on indium-tin-oxide substrate. After the irradiation the films were observed to break-up into NPs through a dewetting mechanism. This mechanism was investigated as a Rayleigh-instability- driven process. In fact, for each used laser fluence, the resulting Au and Ag NPs' mean size and surface-to-surface mean distance were quantified and correlated between them in the framework of the Rayleigh-instability theory showing an excellent agreement. © The Institution of Engineering and Technology 2013.

Enhancing Metastability by Dissipation and Driving in an Asymmetric Bistable Quantum System.

2018

The stabilizing effect of quantum fluctuations on the escape process and the relaxation dynamics from a quantum metastable state are investigated. Specifically, the quantum dynamics of a multilevel bistable system coupled to a bosonic Ohmic thermal bath in strong dissipation regime is analyzed. The study is performed by a non-perturbative method based on the real-time path integral approach of the Feynman-Vernon influence functional. We consider a strongly asymmetric double well potential with and without a monochromatic external driving, and with an out-of-equilibrium initial condition. In the absence of driving we observe a nonmonotonic behavior of the escape time from the metastable regi…

Activation of NF-kappaB and IL-8 by yersinia enterocolitica invasin protein is conferred by engagement of rac1 and MAP kinase cascades.

2003

International audience; Yersinia enterocolitica triggers activation of the nuclear factor (NF)-kappaB and production of the proinflammatory chemokine interleukin (IL)-8 in intestinal epithelial cells. This activation is due to adhesion of the bacteria via their outer membrane protein invasin to the host cells. Using Clostridium difficile toxins that specifically inactivate small GTPases, and transfection of inhibitory proteins of the Rho-GTPases, we demonstrate that Rac1, but not Cdc42 or Rho, is required for activation of NF-kappaB by invasin. Invasin activated the mitogen activated protein kinases (MAPK) p38 and c-Jun N-terminal protein kinase (JNK) but not extracellular signal regulated …