Danger Detection during Fight against Compartment-Fire Using Moving Averages in Temperature Recordings

In compartment fires (houses, buildings, underground, warehouse, etc.), smokes are a major dan- ger during firemen intervention. Most of the time, they are at high temperature (>800?C) and they flow everywhere through many kinds of ducts, which leads to the propagation of the combustion by the creation other fires in places which may be far away from the initial fire. In this paper, we present a new approach of the problem, which allows to better follow the fire behavior and especially to detect the dangers that may appear and endanger firefighters. This approach consists in a mathematical analysis based on the comparison of moving averages centered in the past, calculated on the temperature recordings of the smokes. As a consequence, this method may allow to improve decision support in real time and therefore to improve the security and the efficiency of firefighters in their operations against that kind of fires.

Evolution of a Holocene banner bank controlled by morphodynamics and structural setting of a macrotidal coast: Saint-Brieuc Bay (NW-Europe)

The morphology and internal structure of the Horaine Bank(Bay of Saint-Brieuc,NW France)are described based on multibeam echosounder and high-resolution seismic datasets coupled with vibro-core data.The Horaine Bank shows large-scale bedforms in the lee of a submerged rocky shoal,which allowed defining it as a Banner Bank.The internal structure of the sandbank reveals four seismic units(U1-U4)on a Cambrian basement(U0).The basal unit U1 is interpreted as reworked lowstand fluvial sediments those infilled micro incised valleys during a rise in sea level.This unit is overlain by paleo-coastal barrier sand-spit(U2)whose development was controlled by swell in the context of a rapid rise in sea level.The successive prograding unit(U3)is interpreted as flooding deposits in continuity with unit U2.The unit U4 is characterized by oblique reflectors oriented in two opposite directions.This last unit,dated post 3500 yr BP,corresponds to migrating dunes superimposed on the bank and observable in the high-resolution bathymetric data.The strong correlation between tidal currents and the apparent clockwise migration of dune crests suggests the presence of a tidal gyre controlling the present-day dynamics of most of the Horaine bank dunes.This study proposes a new model for the construction of banner banks characterized by the gradual transition of a sand spit to a banner bank during marine transgression and ensuing hydrodynamic variability.

Hydraulic properties of dune sand-bentonite mixtures of insulation barriers for hazardous waste facilities

The material and elastic properties of rocks are utilized for predicting and evaluating hard rock brittleness using artificial neural networks（ANN）. Herein hard rock brittleness is defined using Yagiz＇method. A predictive model is developed using a comprehensive database compiled from 30 years＇ worth of rock tests at the Earth Mechanics Institute（EMI）, Colorado School of Mines. The model is sensitive to density, elastic properties, and P- and S-wave velocities. The results show that the model is a better predictor of rock brittleness than conventional destructive strength-test based models and multiple regression techniques. While the findings have direct implications on intact rock, the methodology can be extrapolated to rock mass problems in both tunneling and underground mining where rock brittleness is an important control.

Holes Effects in Plane Periodic Multilayered Viscoelastic Media

This work deals with the study of the reflection and transmission properties of plane periodic structures composed of N periods (1 ≤ N ≤ 3) in the MHz frequency range. The period consists of two bounded plates presenting a high acoustic impedance contrast one of which is in aluminum, the other is in polyethylene. The longitudinal and transversal attenuations are considered in polyethylene and neglected in aluminum. We take into account the case of emerging holes in the polyethylene layer. Simulations are based on the stiffness matrix method (SMM) developed by Rokhlin. When attenuation is considered in polyethylene, the reflection coefficients are different depending on the insonification side. The comparison of results without or with holes configurations are performed and showed that throughout holes allow the rapid observation of forbidden bands. The attenuation of the whole multilayer is also determined.

On the Simulation of the Influence of Defects on Immersed Plane Periodic Multilayer Viscoelastic Media

This work deals with the study of a plane periodic multilayer structure in which the elementary stack consists of two plates in contact: one in aluminum (AL) and the other one in polyethylene (PE). These isotropic materials, present a high acoustic impedance contrast. The attenuation of the longitudinal and transverse waves is taken into account in the polyethylene but neglected in the aluminum plate. The effect of different defects is analyzed. Firstly, we focus on the effect of the presence of grease inclusion in the polyethylene plate (considering the two plates of the elementary stack in perfect contact). Secondly, the effect of disbond simulated by the insertion of a thin Teflon layer between the interfaces of the two layers constituting the elementary stack of the multilayer structure is investigated. Finally, the effect of the stacking sequences of the multilayer is analyzed. In order to obtain the effective acoustic parameters of polyethylene layer, allowing to evaluate the reflection and transmission coefficients using the stiffness matrix method developed by Rokhlin et al., four homogenization models are analyzed, then the best one to our configuration is chosen. The comparison of the simulation results is carried out.

Citric Acid-Enhanced Electroremediation of Toxic Metal-Contaminated Dredged Sediments： Effect of Open/Closed Orifice Condition, Electric Potential and Surfactant

Citric acid(CA), a widely used eco-friendly electrolyte, can be employed as an agent for enhancing toxic metal(TM) removal from contaminated dredged sediment using electrokinetic(EK) technology. In this study, dredged harbor sediments co-contaminated by TMs were subjected to enhanced EK treatment using a mixture of chelating agent(CA) and surfactant as an additive in the processing fluids. Several control conditions that may influence the efficiency of TM removal were tested, including open/closed sediment chamber orifices, electric potential gradients(0.5, 1.0, and 1.5 V cm^(-1)), and electrolyte surfactant. Tween 20(4 mmol L-1) was used as a surfactant within the electrolyte to investigate the extent of TM removal in sediment with high organic matter content. The results showed that an open orifice led to a greater electro-osmotic flow(EOF) with moderate TM removal. In contrast, a closed orifice with a nonionic surfactant electrolyte allowed the highest removal of TMs from the matrix. Moreover, increasing the electric potential gradient led to a higher EOF under the open orifice condition, but no significant increase in TM removal was observed owing to a higher accumulation of TMs in the middle of the matrix, caused by the opposite direction of EOF and electro-migration of metal-citrate complexes.