Search results for "BUBBLE"

Benign focal liver lesions: spectrum of findings on SonoVue-enhanced pulse-inversion ultrasonography.

2005

The prevalence of benign focal liver lesions (BFLL) is high both in the general population and in patients with known malignancies. The gray-scale ultrasound (US) technique is usually the first-line imaging modality used in the radiological workup of such lesions, but unfortunately it lacks specificity. Furthermore, Doppler examination may often be unsatisfactory owing to motion artefacts, or when small or deeply located lesions are evaluated. Recently, microbubble-based contrast agents used in combination with gray-scale US techniques, which are very sensitive to nonlinear behavior of microbubbles, have led to a better depiction of both microvasculature and macrovasculature of focal hepati…

Neuroenhancement Bubble?—Neuroenhancement Wave!

2011

On Combinatorial Generation of Prefix Normal Words

2014

A prefix normal word is a binary word with the property that no substring has more 1s than the prefix of the same length. This class of words is important in the context of binary jumbled pattern matching. In this paper we present an efficient algorithm for exhaustively listing the prefix normal words with a fixed length. The algorithm is based on the fact that the language of prefix normal words is a bubble language, a class of binary languages with the property that, for any word w in the language, exchanging the first occurrence of 01 by 10 in w results in another word in the language. We prove that each prefix normal word is produced in O(n) amortized time, and conjecture, based on expe…

Deformation of bubbles in silicon gel insulation under an alternating electric field

2019

The behavior of silicone gel under electrical stress plays a significant role in the reliability and durability of high voltage electronic power devices due to its widespread use for the insulation of IGBT modules and other components. The charges accumulation at the bubble boundaries leads to significant displacements due to the establishment of Coulombic forces and the high deformability of colloidal system. The main purpose of this work is to validate a numerical approach useful to investigate, for a given silicone gel, the non-linear relation between the applied HVDC stress and the electric field over an air bubble within the insulation bulk. The analysis has been carried out by means o…

Not all bull and bear markets are alike: insights from a five-state hidden semi-Markov model

2022

This paper employs the hidden semi-Markov model and a novel model selection procedure to detect different states in the US stock market. The empirical results suggest that the market is switching between five states that can be classified into three bull states and two bear states. The three bull states are categorized as a low volatility bull market, a high volatility bull market, and a stock market bubble. One of the bear states represents a regular bear market, while the other one corresponds to either a stock market crash or a market correction. The paper demonstrates that the five-state model is consistent with a number of stylized facts and provides many valuable insights into the dyn…

2017

Strombolian volcanism is a ubiquitous form of activity, driven by the ascent and bursting of bubbles of slug morphology. Whilst considerable attention has been devoted to understanding the behaviour of individual slugs in this regime, relatively little is known about how inter-slug interactions modify flow conditions. Recently, we reported on high temporal frequency strombolian activity on Etna, in which the larger erupted slug masses were followed by longer intervals before the following explosion than the smaller bursts (Pering et al., 2015). We hypothesised that this behaviour arose from the coalescence of ascending slugs causing a prolonged lag before arrival of the next distinct bubble…

2003

Analysis of joining and division of gas bubbles based on measurements of their motion trajectories

2014

The paper presents considerations on motion of a group of air bubbles. Special attention has been paid to interactions between them. The author presents the test stand structure and the idea of image tomograph used for measurements of bubble motion trajectories. The results of measurements have been presented in a three-dimensional space, and next characteristic behaviours of the moving bubbles were analyzed. Some basic mechanisms of the gas bubble division have been classified. DOI: http://dx.doi.org/10.5755/j01.mech.20.1.6596

A unique microstructure of the fiber networks deposited from foam-fiber suspensions

2015

Abstract Fiber networks can be formed using aqueous foam as the suspending medium. The mean bubble size of the foam affects the resulting pore-size distribution of the fiber network. The foam–fiber interactions cause in particular an increase in the proportion of large micropores of the network, in comparison with the fiber networks that result from traditional water forming at a similar material density. Experiments were carried out for two different types of cellulose fiber, and characterization of the resulting pore structure was based on X-ray microtomography of the resulting fiber networks. The unique pore structure obtained with foam forming was reflected in various macroscopic proper…

Non-supersymmetric AdS6 and the swampland

2021

We discuss infinite families of non-supersymmetric AdS$_6$ solutions in Type IIB string theory. They are siblings of supersymmetric solutions which are associated with $(p,q)$ 5-brane webs and holographically dual to 5d SCFTs engineered by those brane webs. The non-supersymmetric backgrounds carry identical 5-brane charges and are connected to the supersymmetric ones by RG flows. We study the stability of the non-supersymmetric solutions, identifying perturbative and non-perturbative decay channels for all the backgrounds explicitly available. We also identify likely decay mechanisms for solutions that have not been constructed explicitly but may be expected to exist based on brane web cons…