Resistance of thermally modified ash (<Emphasis Type="Italic">Fraxinus excelsior</Emphasis> L.) wood under steam pressure against rot fungi,soil-inhabiting micro-organisms and termites

Thermal modification processes have been developed to increase the biological durability and dimensional stability of wood. The aim of this paper was to study the influence of ThermoWood^® treatment intensity on improvement of wood decay resistance against soil-inhabiting micro-organisms, brown/white rots and termite exposures. All of the tests were carried out in the laboratory with two different complementary research materials. The main research material consisted of ash (Fraxinus excelsior L.) wood thermally modified at temperatures of 170, 200, 215 and 228 °C. The reference materials were untreated ash and beech wood for decay resistance tests, untreated ash wood for soil bed tests and untreated ash, beech and pine wood for termite resistance tests. An agar block test was used to determine the resistance to two brown-rot and two white-rot fungi according to CEN/TS 15083-1 directives. Durability against soil-inhabiting micro-organisms was determined following the CEN/TS 15083-2 directives, by measuring the weight loss, modulus of elasticity (MOE) and modulus of rupture (MOR) after incubation periods of 24, 32 and 90 weeks. Finally, Reticulitermes santonensis species was used for determining the termite attack resistance by non-choice screening tests, with a size sample adjustment according to EN 117 standard directives on control samples and on samples which have previously been exposed to soil bed test. Thermal modification increased the biological durability of all samples. However, high thermal modification temperature above 215 °C, represented by a wood mass loss (ML%) due to thermal degradation of 20%, was needed to reach resistance against decay comparable with the durability classes of ‘‘durable’’ or ‘‘very durable’’ in the soil bed test. The brown-rot and white-rot tests gave slightly better durability classes than the soil bed test. Whatever the heat treatment conditions are, thermally modified ash wood was not efficient against termite attack neither before nor after soft rot degradation.     

Suppression of otoacoustic emission is unchanged after several minutes of contralateral acoustic stimulation

The influence of variable durations of contralateral acoustic stimulation on the suppression of click-evoked otoacoustic emissions was investigated in order to determine whether olivocochlear efferent fibers are equally effective whatever the acoustical stimulation duration or if they show fatigue. The suppression effect was measured for contralateral stimulus durations ranging from 10 to 180 s prior to the onset of otoacoustic emission recording, and continuing throughout the recording time (60 s). No significant stimulus duration effect was found.     

Shelf life prediction of oxygen‐sensitive products: The influence of moisture on prediction accuracy for freeze‐dried coffee

Optimised packaging requires that properties are matched to the protection requirements of food for its shelf life duration. Benefits include reduced packaging costs, use volumes, and potentially improved environmental performance. The ability to predict product shelf life in different materials can assist in selecting optimal packaging. However, the availability of such tools is limited, and risk for over packing exists. The aim with this work is to develop a prediction approach which can be applied to assist users to select more optimal packaging materials. Soluble coffee was used to develop the approach, where oxygen consumption of the product is used as a quality indicator. The effect of moisture content on O₂ consumption was studied to determine its influence on prediction accuracy. Samples were prepared with different levels of moisture content. O₂ consumption rates were measured, and a notable influence of moisture was observed. A model was developed to predict the O₂ consumption of the product when packed in a pouch. The model considers oxygen and moisture permeation properties of the packaging film, O₂ and moisture differential between the interior and exterior of the packaging, and the evolution of the O₂ consumption rate as a function of moisture increase. To test model accuracy, coffee samples were packed in flexible pouches, and O₂ consumption was measured which showed that predicted and measured values shared the same trend characteristics. We show that considering both moisture and O₂ ingress simultaneously leads to more precise shelf life prediction as oxidation rate is influenced by moisture content.     

A combination of capillary and dielectrophoresis-driven assembly methods for wafer scale integration of carbon-nanotube-based nanocarpets

The wafer scale integration of carbon nanotubes (CNT) remains a challenge for electronic and electromechanical applications. We propose a novel CNT integration process relying on the combination of controlled capillary assembly and buried electrode dielectrophoresis (DEP). This process enables us to monitor the precise spatial localization of a high density of CNTs and their alignment in a pre-defined direction. Large arrays of independent and low resistivity (4.4 × 10(-5) Ω m) interconnections were achieved using this hybrid assembly with double-walled carbon nanotubes (DWNT). Finally, arrays of suspended individual CNT carpets are realized and we demonstrate their potential use as functional devices by monitoring their resonance frequencies (ranging between 1.7 and 10.5 MHz) using a Fabry-Perot interferometer.     

Optimal wave with respect to efficiency in percussive drilling with integral drill steel

The problem considered is that of finding the optimum wave of given finite duration that maximizes the efficiency of conversion of wave energy into work in percussive drilling with integral drill steel (drill rod with integrated bit). A 1D model is used for the drill rod, and the bit-rock interaction is represented by a piecewise linear force versus penetration relation with different penetration resistances for primary loading and for unloading/reloading. A functional expressing the dependence of the efficiency on the incident wave is derived and maximized. The optimal incident wave has exponential shape with time constant for the growth rate equal to the characteristic response time of the percussive drill system, including the rock. The maximal efficiency increases monotonously with the duration of the optimal wave. It approaches zero for very short waves and unity for very long waves. Optimal waves of short duration are close to rectangular while those of long duration approach the semi-infinite exponential wave derived by Long in the 1960s. Optimal waves of medium or longer duration give significantly higher efficiencies than commonly used rectangular waves of the same duration.     

Functional maturation of cochlear active mechanisms and of the medial olivocochlear system in humans

The aim of this study was to investigate the functional development of cochlear active mechanisms and of the medial efferent olivocochlear system. Otoacoustic emissions (evoked and spontaneous) were recorded in 42 preterm neonates (conceptional age ranging form 33 to 39 weeks) and a control group of 20 young normal-hearing adults. Medial olivocochlear system activity was examined by coupling evoked otoacoustic emission recording to a contralateral stimulation. Otoacoustic emission recordings were carried out using the Otodynamic ILO88 software and hardware. The stimuli were unfiltered clicks and the contralateral stimulation was broad band noise of 50 and 70 dBSPL delivered by an Adam generator. The results revealed the presence of EOAEs and SOAEs from at least 33 weeks in humans, suggesting that the functional maturation of the outer hair cells is nearly complete at that age. The study further revealed that the contralateral stimulation had no effect on evoked otoacoustic emissions in preterm neonates. The lack of activity observed in medial olivocochlear system indicated functional immaturity here, at least before full-term birth.     

Resource integration using a large knowledge base in Carnot

A method for integrating separately developed information resources that overcomes incompatibilities in syntax and semantics and permits the resources to be accessed and modified coherently is described. The method provides logical connectivity among the information resources via a semantic service layer that automates the maintenance of data integrity and provides an approximation of global data integration across systems. This layer is a fundamental part of the Carnot architecture, which provides tools for interoperability across global enterprises     

Comparative influence of repeated measurement and of attention on evoked otoacoustic emissions

This study compared the influence of an auditory attention task and of repetitive measures on the peripheral auditory system, using evoked otoacoustic emissions (EOAEs). The experimental task protocol comprised three sessions (pre-control, attention and post-control conditions) with, in each session, six measurements of EOAEs, at intervals of about 60 seconds, while the other ear was receiving two pure tones of 2,500 and 750 Hz, with a probability of appearance of 20% and 80%, respectively. In the contralateral attention condition, the subject had to count the number of the less frequent high pitched sounds. A long duration protocol (20 min for the total experiment) was used in order to examine a possible time-effect on EOAEs. An increase in EOAE amplitude during the second and third sessions, with linear saturation around the last measurements, was observed. While no attention effect could be identified, a time-effect seemed to be present. Possible explanations for the influence of repeated measurements on EOAEs are discussed. Moreover, EOAE amplitudes of subjects presenting spontaneous otoacoustic emissions were compared to those of subjects without SOAEs: significant differences were found, showing the particularity of cochleas emitting SOAEs.     

A unified framework for peak detection and alignment: application to HR-MAS 2D NMR spectroscopy

In this paper, we propose a new scheme to detect and align simultaneously peaks that correspond to different metabolites within a biopsy. The proposed peak detection and alignment scheme is based on the use of evidence theory, which is well suited to model uncertainty and imprecision characterizing the 2D NMR HR-MAS spectra. Consequently, we propose the coupling use of Bayesian and fuzzy set theories to model and quantify the imprecision degree, which is then exploited to define the mass function. We particularly show that our new mass function definition and the use of evidence theory for peak detection and alignment achieve consistently high performance compared to a Bayesian scheme on both synthetic and real spectra. The high quality of peak alignment precision reached by the use of evidence theory allows us to efficiently detect reliable biomarkers, which is an essential step for a better therapeutic and human complement system management in case of multiple sclerosis disease, cancer, etc.     

Topology optimization for microstructural design under stress constraints

This work aims at introducing stress responses within a topology optimization framework applied to the design of periodic microstructures. The emergence of novel additive manufacturing techniques fosters research towards new approaches to tailor materials properties. This paper derives a formulation to prevent the occurrence of high stress concentrations, often present in optimized microstructures. Applying macroscopic test strain fields to the material, microstructural layouts, reducing the stress level while exhibiting the best overall stiffness properties, are sought for. Equivalent stiffness properties of the designed material are predicted by numerical homogenization and considering a metallic base material for the microstructure, it is assumed that the classical Von Mises stress criterion remains valid to predict the material elastic allowable stress at the microscale. Stress constraints with arbitrary bounds are considered, assuming that a sizing optimization step could be applied to match the actual stress limits under realistic service loads. Density–based topology optimization, relying on the SIMP model, is used and the qp–approach is exploited to overcome the singularity phenomenon arising from the introduction of stress constraints with vanishing material. Optimization problems are solved using mathematical programming schemes, in particular MMA, so that a sensitivity analysis of stress responses at the microstructural level is required and performed considering the adjoint approach. Finally, the developed method is first validated with classical academic benchmarks and then illustrated with an original application: tailoring metamaterials for a museum anti–seismic stand.