Search results for "conduit"

Visual scale factor for speed perception rendering in car driving simulation

2010

Speed perception is an important task that the driver must perform continuously to control his/her vehicle. It appears that many factors influence this perception: height of the point of view, field of view, realism of the environment, but also realism of audio and proprioceptive rendering. If some high-performance car driving simulators are able to render motion satisfactorily according to all these criteria, it is not always the case. As a result, speed perception is thus often under estimated, leading into producing higher speeds than in real conditions. Perceptual validity is then not good enough to study driver's behavior. To solve this problem, a technique has recently seen the light,…

2016

The mechanisms of hazardous silicic eruptions are controlled by complex, poorly-understood conduit processes. Observations of recent Chilean rhyolite eruptions have revealed the importance of hybrid activity, involving simultaneous explosive and effusive emissions from a common vent. Such behaviour hinges upon the ability of gas to decouple from magma in the shallow conduit. Tuffisite veins are increasingly suspected to be a key facilitator of outgassing, as they repeatedly provide a transient permeable escape route for volcanic gases. Intersection of foam domains by tuffisite veins appears critical to efficient outgassing. However, knowledge is currently lacking into textural heterogeneiti…

Tracking dynamics of magma migration in open-conduit systems

2016

Open-conduit volcanic systems are typically characterized by unsealed volcanic conduits feeding permanent or quasi-permanent volcanic activity. This persistent activity limits our ability to read changes in the monitored parameters, making the assessment of possible eruptive crises more difficult. We show how an integrated approach to monitoring can solve this problem, opening a new way to data interpretation. The increasing rate of explosive transients, tremor amplitude, thermal emissions of ejected tephra, and rise of the very-long-period (VLP) seismic source towards the surface are interpreted as indicating an upward migration of the magma column in response to an increased magma input r…

The percolation threshold and permeability evolution of ascending magmas

2017

Abstract The development of gas permeability in magmas is a complex phenomenon that directly influences the style of a volcanic eruption. The emergence of permeability is linked to the concept of percolation threshold, which is the point beyond which gas bubbles are connected in a continuous network that allows gas escape. Measurements of the percolation threshold, however, range from ∼30 to 78 vol%. No known combination of parameters can explain such a wide range of threshold values, which affects our understanding of the relationship between percolation and permeability. We present permeability calculations on bubble-bearing rhyolitic melts that underwent experimental decompression. Sampl…

2016

Recent gas flux measurements have shown that Strombolian explosions are often followed by periods of elevated flux, or “gas codas,” with durations of order a minute. Here we present UV camera data from 200 events recorded at Stromboli volcano to constrain the nature of these codas for the first time, providing estimates for combined explosion plus coda SO2 masses of ≈18–225 kg. Numerical simulations of gas slug ascent show that substantial proportions of the initial gas mass can be distributed into a train of “daughter bubbles” released from the base of the slug, which we suggest, generate the codas, on bursting at the surface. This process could also cause transitioning of slugs into cap b…

2017

Abstract. The aim of this study is to present a framework that provides new ways to characterize the spatio-temporal variability of lateral exchanges for water flow and solute transport in a karst conduit network during flood events, treating both the diffusive wave equation and the advection–diffusion equation with the same mathematical approach, assuming uniform lateral flow and solute transport. A solution to the inverse problem for the advection–diffusion equations is then applied to data from two successive gauging stations to simulate flows and solute exchange dynamics after recharge. The study site is the karst conduit network of the Fourbanne aquifer in the French Jura Mountains, wh…

Four News Media Roles Shaping Agenda-building Processes

2019

This chapter identifies, defines and explores four news media roles of conduit, facilitator, mediator and political actor through which the media participate with corporate, social and political actors in agenda-building processes. The framework of the media’s four agenda-building roles sheds light on how the news media perform their various roles as well as how other actors, such as organizations and media audiences, are able to mobilize the media performing these roles. This framework helps explain how and why media roles affect the way actors are able to influence the media agenda with the intention of shaping the public agenda. peerReviewed

Extraperitoneal ileal conduit

2011

Today incontinent urinary diversion continues to be the most widely used diversion technique. A current Medicare evaluation showed that 80% of patients undergoing urinary diversion in the USA are subject to reconstruction by means of an ileal conduit [1]. In particular, older patients, patients with comorbidities, and women more frequently receive an incontinent urinary diversion [2,3]. Even with improved perioperative clinicalcare pathways, urinary diversion remains a morbid procedure. Complications are still common after urinary diversion with ≈ 27% patients re-admitted in the first 90 days after BJUI

Fully robotic Ivor–Lewis esophagectomy (RAMIE4) for esophageal cancer after emergency surgery and ligation of the gastroduodenal artery

2018

We report a case of a 69-year-old patient with esophageal cancer and severe upper gastrointestinal bleeding during neoadjuvant radiochemotherapy who required mass transfusion followed by complex emergency procedures. Despite endoscopic stenting, the bleeding recurred, and thus emergency open surgery was required. Gastric wedge resection of the minor curvature necessitated by perforation caused by the endoscopic stent maneuver and duodenotomy with ligation of the gastroduodenal artery, as the cause of persistent intraluminal bleeding, were performed. The already prepared gastric conduit during the emergency operation did not become ischemic, even though the gastroduodenal artery, left gastr…

Towards real-time detection of cognitive effort in driving: Contribution of cardiac measurement

2016

En 2013, on estime que 40 à 50% des accidents corporels seraient dus à des défauts d'attention de la part du conducteur. Des études récentes ont mis en évidence la possibilité de détecter des états attentionnels dégradés afin de pouvoir mieux assister le conducteur ; ce thème de recherche représente donc un nouveau gisement de sécurité routière. Cette étude se concentre sur la détection de l'effort cognitif fournit par les conducteurs et cherche, par l'étude de la variation du rythme cardiaque, à identifier un indicateur d'effort sensible sur de courtes fenêtres temporelles.Chacun des 18 participants a passé 8 conditions expérimentales sur simulateur de conduite : la moitié où seule une tâc…