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Apprendre et enseigner avec le numérique sont des activités à étudier et mettre au regard des espaces support de ces pratiques du numérique, et du tissu social correspondant. Nous proposons une étude des porosités d’usages du numérique entre espaces situés, à savoir la sphère privée et la sphère scolaire, que ce soit pour les apprenants ou leurs enseignants. Finalement, les enseignants avec de fortes pratiques numériques éducatives, ont-ils de fortes pratiques numériques personnelles pour les alimenter, ou réciproquement? De même, les apprenants avec de fortes pratiques numériques personnelles sont-ils plus aptes à apprendre avec le numérique à l’école, plus motivés par l’instrumentation des dispositifs pédagogiques? Pour répondre à ces questions et étudier toutes formes de porosités entre sphères privée et éducative, nous utilisons les résultats d’une enquête sur les usages du numérique, des apprenants du collège à l’université et de leurs enseignants. Nous démontrons que plusieurs formes de porosités existent, avec un sens de transfert le plus souvent bien défini. Enfin, ces espaces situés et les porosités afférentes peuvent être des révélateurs de hubs sociaux et éducatifs, ainsi que gage de prescriptions pour une meilleure prise en compte du numérique en éducation.

La liaison autoroutière dite « autoroute arabe », qui reliera Beyrouth à Damas et aux autres villes du Proche et du Moyen-Orient, risque de perturber les milieux de vie actuels des habitants des territoires concernés. Traversant des territoires villageois et urbains, cette autoroute remettra sans doute en cause les pratiques sociales et les ressources des habitants proches des voies actuelles et futures. L’étude de cas choisi correspond à une section de l’autoroute non encore exécutée qui suscite un débat récurrent depuis les années 1960. En s’inspirant de la Convention européenne du paysage, l’article montre que la construction de cet équipement devrait s’accompagner de la consultation des habitants et des élus locaux concernés pour définir les tracés, choisir les échangeurs et atténuer les impacts environnementaux et paysagers. Notant que cet article fait partie d'une recherche dans le cadre d'une thèse doctorale.

Copyright of Irrigation & Drainage is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The textile industry uses large amount of water and organic dyes to tint their products. These synthetic dyes are toxic and cause water coloring. This results in colored wastewater that must be treated before being discharged. In addition, most dyes are not biodegradable, and once released they alter the aquatic environment. Among the processes for treating these effluents, adsorption is an easy and a costeffective process to implement. The objective of this study is the preparation of biochars from common reed applicable for the discoloration of effluents used in the textile industry. Common reed (Phragmites australis) has been collected from the Sed-Ksob river of M'sila (Algeria) and used as precursor for the production of biochars activated by phosphoric acid. The surface chemistry of the prepared materials has been characterized using selective titration (Boehm assay), TGA analysis and pH of point zero charge (pHpzc) measurements. The porous texture has been investigated by using methylene blue adsorption and iodine number measurements. The results of the TGA analysis and the Boehm assay show the presence of many superficial functional groups on the surface of the biochars. The amount of oxygenated functional groups on all the prepared biochars depends on the impregnation ratio of phosphoric acid, except for the one obtained at 150% impregnation ratio. The adsorption of methylene blue and the iodine test indicate an increase in the specific surface area with an increase in the impregnation ratio due to the development of the microporosity and the mesoporosity. The adsorption properties of methyl orange, an anionic dye, were studied on the prepared biochars as function of concentration, contact time, and temperature. The Langmuir model describes well the equilibrium adsorption of methyl orange on the prepared biochars. The adsorption kinetics are described by the pseudo-second order and the liquid film diffusion models. An endothermic physical adsorption of methyl orange on the prepared biochars has been highlighted. [ABSTRACT FROM AUTHOR]

• Temperature fluctuations affect the colour of frozen beef. • Temperature fluctuations cause recrystallisation of ice, damaging muscle structure. • Pore data can be used as indicators to optimise the meat quality of frozen beef. • Porosity, volume, and diameter of ice crystals can be used to optimise meat quality. Temperature fluctuation during storage and distribution of frozen foods has been a major concern in the frozen food industry. Recrystallisation of ice due to fluctuations in storage temperature can induce microstructural modifications of meat products, leading to irreversible cell and tissue damage, degrading the quality of frozen meat during storage. To explore the effects of temperature fluctuation on the quality of frozen beef, four experimental groups were used in this study: storage at a constant −18±0.1°C, and fluctuations between −18 to −17 °C, −18 to −15 °C, and −18 to −13 °C. The parameters analysed were drip loss, colour, muscle fibre morphology, pore distribution, and Pearson correlation coefficients. Experimental results showed that, with an increase in temperature fluctuation, the rate of drip loss increased, redness (a*) decreased, yellowness (b*) increased, while chroma (C*) expressed negative correlation. Computed Tomography scans showed that with the increase in temperature fluctuation, the fibre structure of meat gradually collapsed, porosity increased, and the pore volume increased steadily. The number of pores, however, demonstrated a decreasing trend. Scanning electron microscopy showed that increasing temperature fluctuation damaged the dimensional structure of the fibre and increased the pore diameter. Pearson correlation coefficients showed that porosity, pore volume, and pore diameter were significantly correlated to each other, which were also correlated to drip loss, a*, and b*. The structural changes due to temperature fluctuations affect the colour and final meat quality of frozen beef. [ABSTRACT FROM AUTHOR]

Copyright of Matériaux et Techniques is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Matériaux et Techniques is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights • Liquid drainage characteristics of metal foams were experimentally investigated in injection test. • Effects of sloshing conditions on drainage characteristics of metal foams were analyzed. • The shapes of liquid retained in metal foams were observed. • A correlation for predicting the liquid retention mass of metal foams was developed. Abstract For applying metal foam in enhancing the condensation heat transfer of shell-and-tube heat exchangers, the liquid drainage characteristics of metal foams under sloshing conditions are investigated experimentally. The experimental conditions include the pore density of 5-40 PPI and the porosity of 0.85–0.95. The results show that, the liquid drainage performance of metal foams is improved by sloshing motions; as the sloshing frequency and angle increase, the liquid retention of metal foam decreases by a maximum of 44%. A sloshing impact factor is employed to evaluate the influence of sloshing motions, and the impact factors of rolling, swaying and heaving motions are within 0.56–1.0, 0.93–1.0 and 0.92–1.0, respectively. With the increasing PPI, the shape of liquid retained in metal foam changes from droplet to scattered or full layer, which has significant effect on the drainage performance. A correlation for predicting the mass liquid retention was developed within a deviation of ±20%. [ABSTRACT FROM AUTHOR]

Copyright of Matériaux et Techniques is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to optimize the parameters of metal foam heat exchanger operating under dehumidifying conditions, the influence of pore density and porosity on the heat transfer and pressure drop characteristics of wet air in metal foam under different conditions were investigated experimentally. The experimental conditions cover PPI (number of pores per inch) of metal foam from 5 to 40 and porosity from 85% to 95%. The results show that, as PPI increases, the global heat transfer coefficient always increases under low relative humidity conditions, while it initially increases then decreases under high relative humidity conditions, presenting a maximum increment of 12–21% at 20 PPI. As the porosity increases from 85% to 95%, the global heat transfer coefficient of wet air in metal foam decreases maximally by 32%, and the pressure drop of wet air in metal foam decreases by 47%. [ABSTRACT FROM AUTHOR]

Résumé De nombreuses modalités d’imagerie ont été décrites pour le diagnostic et la surveillance de l’ostéoporose (OP), l’arthrose et les maladies rhumatismales inflammatoires. Ces dix dernières années, la recherche clinique a identifié le scanner périphérique à haute résolution (HRpQCT) comme une technique à la fois précise et non invasive pour l’étude des maladies ostéoarticulaires. Il permet notamment d’explorer la microarchitecture de l’os cortical et trabéculaire aux extrémités distales du tibia et du radius. D’autres applications ont été développées, comme l’étude des propriétés mécaniques par l’analyse en éléments finis. Dans des études cas témoin et transversales, les paramètres microarchitecturaux ont ainsi discriminé les sujets présentant des fractures indépendamment de la DMO surfacique (DMOs). Par ailleurs, les paramètres microstructurels permettent de prédire les fractures incidentes chez les femmes ménopausées. Dans les maladies métaboliques associées à une fragilité osseuse, le scanner HRpQCT peut également être utilisé pour explorer les changements osseux. Des études sur les maladies articulaires l’ont décrit comme un outil remarquable pour évaluer l’érosion osseuse et le pincement de l’interligne dans la main. Le présent article propose un aperçu de cette technique d’imagerie. [ABSTRACT FROM AUTHOR]

This paper discusses the residues of a somatic countertransference that revealed its meaning several years after apparently successful analytic work had ended. Psychoanalytic and Jungian analytic ideas on primitive communication, dissociation and enactment are explored in the working through of a shared respiratory symptom between patient and analyst. Growth in the analyst was necessary so that the patient's communication at a somatic level could be understood. Bleger's concept that both the patient's and analyst's body are part of the setting was central in the working through. [ABSTRACT FROM AUTHOR]

The laser filament winding of preimpregnated thermoplastic tapes requires a multiphysical analysis, leading to the control of transformation parameters. Such an analysis is generally carried out by considering the raw material, the tape, as a "standard material". Consequently, conclusions can be biased due to the material variability, which presents at least a natural variability, at worst local or repeated defects. Therefore, in the present work, the subject under study is the thermal behavior of the tape, independently of the manufacturing conditions. The detected thermal irregularities are then put into perspective with the irregularities of the material, such as thickness variations or porosities. [ABSTRACT FROM AUTHOR]

This work aims to reveal the influence of thermal treatment on thermal conductivity of a clay-based raw material. The analysis of the effect of the porous network and solid skeleton on thermal conductivity has been performed by numerical simulation. Three steps were combined: (i) elaboration, (ii) characterisation, (iii) validation and comparison with experimental results. In filigree, the objective is to make an insulating material for the building field while decreasing energy of fabrication. After the step of elaboration, the porosity was evaluated experimentally by pycnometer and mercury intrusion porosimeter and numerically by means of micrographs observations. The effective thermal conductivity was evaluated using the laser flash technique and compared to results obtained by numerical simulation using ABAQUS software. The influence of the microstructure characteristics was highlighted by the numerical study which enables to overcome the limitation of the classical analytical models. As results, we observe that when the temperature of fabrication decreases of about 200 °C, the pore volume fraction is multiplied by six while the thermal conductivity decreases four times. The mechanical properties remain acceptable for a construction field. These tendencies were confirmed by both experimental and numerical approaches. [ABSTRACT FROM PUBLISHER]

In this paper, an analytical solution is presented for vibration behaviour analysis of functionally graded materials plates (FGM). During manufacture of these plates, defects such as porosities can appear. Those can change the entire behaviour of these plates. A method based on a higher shear deformation theory will be presented to study the free vibration of FGM plates resting on elastic foundation. Two different porosity distributions through thickness direction of plate will be retained. The elasticity moduli and mass density of these plates are assumed to be graded in the thickness direction according two distribution patterns. The governing equations are obtained through the Hamilton's principal and the closed form solutions in terms of natural frequencies are obtained by using Navier technique. The numerical results obtained through the present analysis are compared with the ones available in the literature, and a parametric study is carried out to investigate the influence of the varying porosity distributions on the vibration response of FGM plates resting on elastic foundation. [ABSTRACT FROM AUTHOR]

Following the environnement grenelle, reaching 10% of bio-resourced materials in building sector except wood is one of goals until 2020. Among these agro-materials, one can distinguish the hemp concrete. Based on hemp hurds and mineral binders including lime or polymer as starch, the hemp composites are appreciated for their hydrothermal and acoustic properties. In this study, a vegetal binder based on starch and extracted from wheat is used with treated and non-treated hemp hurds to form an ecological composite. The studied hemp-starch is prepared with a ratio (H/S = 3,3). Hygrothermal properties such as moisture buffering value, sorption isotherm, water vapor permeability, thermal conductivity, and heat capacity are experimentally studied. The pore size distribution is performed using mercury porosimetry. Results reveal that the hemp-starch composite may be a promising solution in the insulation field due to its relatively low thermal conductivity and capacity to regulate the indoor relative humidity. [ABSTRACT FROM AUTHOR]

Copyright of Matériaux et Techniques is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Metal organic frameworks are porous coordination networks that offer tunable structures via modular synthetic routes. It is well established that zinc 3-amino-1,2,4-triazolate (ATz) forms structures with cationic layers. These layers can be pillared by anions to generate pores. We present three new Zn2(ATz)2(A) structures with A = 1,4-benzenedicarboxylate (BDC) pillars, 2-amino-1,4-benzene-dicarboxylate (BDC-NH2) and 2-methyl-1,4-benzenedicarboxylate (BDC-Me) to give the CALF-24 series of metal organic frameworks. Initially, these compounds were prepared to assess their CO2 capture ability and these data are presented. More significantly, comparing these and published ZnATz relatives, primarily from the group of X.M. Chen, we propose that, for layered systems with some flexibility in their bonding, larger pores actually result by pillaring with shorter linkers. While this may seem counterintuitive, a rationale is offered as borne out by the library of existing data. This offers a general concept for making porous materials based on the rigidity of the building units. [ABSTRACT FROM AUTHOR]

A common practice to provide additional water for the hydration process of cement is to use special aggregates that act as agents incorporating water to the concrete (lightweight natural aggregates or polymers). Previous studies have suggested that normal-density high-absorption limestone aggregates may produce a similar effect. The aim was to determine if they can function as an internal curing agent. The methodology consisted of concrete specimens employing two types of aggregates and subjected to three different curing treatments. Results showed similar values of compressive strength and porosity among the concrete cured under wet and dry treatments for the high-absorption limestone aggregate but not for the river rock aggregate. Thus, this effect was attributed to the internal curing properties of the high-absorption limestone aggregate. [ABSTRACT FROM AUTHOR]

This work, which returns within the framework of a research program of the ITGC in Oued Smar, concerns an analysis of three farming techniques effect, for the cereal installation, on the soil properties physics and the consequence on the roots development and on the durum wheat yield. The results analysis shows clearly that the technique used has an effect on the evolution of moisture, on the porosity and on the penetrometric resistance of the soil. The water content in the soil is preserved better with the direct drilling, its value reaches from 12,97% before sowing to 16,51% at the ear development stage on the plowed parcel (TC); it passes from 13,83% to 16,73% on the minimum tilling (TM) parcel and from 14,28% to 18,27 on the direct drilling (SD) parcel. Porosity is slightly more important with the conventional technique. As regards penetrometric resistance, the soil is more resistant on the parcel in direct drilling where it reaches 15,84 daN/cm 2. The results obtained also show that the roots system is developed more on parcel worked with the conventional method than on those worked in direct drilling and minimum work. The estimated yield are respectively 36,19 q/ha for the direct drilling and 50,03 q/ha for conventional work and it is only 35,7 q/ha on the parcel worked with the chisel. [ABSTRACT FROM AUTHOR]

The self-compacting concrete have particularities of compositions compared to vibrate concretes, among these peculiarities a high volume of fines and a high volume of paste which is also responsible for their rheological behavior. In addition, the texture very complex of self-compacting concrete in the hardened state is the subject of many researches. This texture is governed by the hardened cement paste which is a porous material. In this work, we focus, for a part in the study, of the effect of the limestone fillers on the fluidity of self compacting pastes and also the effect of limestone fillers on the evolution of porosity. An experimental program was conducted over self compacting pastes where limestone fillers have been substituted in blended cement, to study their effect on porosity and pore distribution of these pastes at 7days, 28days and 90 days using the mercury porosimeter. The results show that the substitution of cement by limestone fillers seems to lead to a reduction in capillary porosity of selfcompacting pastes. [ABSTRACT FROM AUTHOR]

Copyright of Silva Lusitana is the property of Unidade de Investigacao de Silvicultura e Productos Florestais and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A first-principles model for predicting the evolution of the porosity of a frost layer over time was advanced. The theoretical model was used together with experimental data obtained elsewhere to put forward a semi-empirical correlation for the frost density as a function of the time, and the modified Jakob number, which carries information about the thermodynamic conditions of the air stream and the chilled surface. When compared to experimental data, the proposed correlation showed errors within ±10% bounds. Comparisons with other frost density correlations available in the open literature are also reported. [ABSTRACT FROM AUTHOR]

The combined heat and mass transfer mechanisms owing to the temperature and humidity ratio differences and their influence on the efficiency of different exponential type porous fin configurations are analyzed in this paper. The closed-form temperature solutions for an exponential impermeable dry fin as obtained in an earlier publication (Turkyilmazoglu, 2012) are extended here to the case where the surface of the fin is fully wet and porous. A comparison with the traditional straight porous fins proves that the fin tip temperature and efficiency of the exponential porous wet fins are much better than those of corresponding to the straight porous wet fins. [ABSTRACT FROM AUTHOR]

Durability is one of the main concerns in the design, realization and maintenance of civil engineering works. Among the diseases of structures exposed to the marine environment, the reinforcement corrosion is the main cause of deterioration of reinforced concrete structures and the largest in terms of maintenance. This phenomenon is the result of many factors, more or less coupled, and related material to the environment. Concrete is more durable that it resists the penetration of aggressive agents. This quality is intrinsically dependent on several parameters: W/C, type of cement, formulation, conditions and duration of cure... An experimental program has enabled us to perform in the laboratory, test of the interactions isotherm to determine the amount of chlorides attached to a plain concrete using two strength classes of cement (CEMII/A-42.5 Beni Saf and CEMII/A-32.5 Zahana), our results show that the influence of the W/C ratio and the nature of cements used in the determination of chlorides in concrete is not considered very significant. We also performed tests of migration to measure the diffusion coefficient of chlorides and there has been an increase in the diffusion coefficient of chloride with increasing W/C ratio for all studied concretes, however, this ratio decreases with increase in the strength class of cement. In addition, a longer duration of cure favors the relative decrease of the diffusion coefficient. [ABSTRACT FROM AUTHOR]

Copyright of Matériaux et Techniques is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The organic content of a soil inhibits the effectiveness of cement stabilization. The study tested the use of various admixtures with cement to assess their effect on the size of the granules created and the size of the pores, using SEM imagery and a WD-5 image processing system to determine the shape parameters of structure units and pores. The results show that different admixtures play different roles in the stabilization process. Although the samples with cement and an accelerator and cement with aluminium sulfate were effective, the most improvement was achieved with cement plus crystal calcium sulfate. [ABSTRACT FROM AUTHOR]

A borehole is developed in a shallow multi-layered aquifer and used to derive the porosity, specific storage and hydraulic conductivity of the aquitard. Local values of hydrodynamical parameters are estimated from petrophysical analysis of core samples, and the empirical relationship between porosity and permeability. Vertical diffusivity is determined from the response of the aquitard to a loading cyclic signal using pressure records at different depths. Hydraulic conductivities deduced from the petrophysical analysis ranged from 10−8to 10−10m s−1and are comparable with those of facies of marine/lacustrine clay observed in samples. The permeability values calculated based on diffusivity are within the range 10−9to 10−11m s−1with a quasi-systematic bias of one order of magnitude. These values are average for a larger part of the aquitard and correspond to an integrated value. The methodology retained for the aquitard characterization is discussed with emphasis on the implications for the management of a complex aquifer system. Citation Larroque, F., Cabaret, O., Atteia, O., Dupuy, A., and Franceschi, M., 2013. Vertical heterogeneities of hydraulic aquitard parameters: preliminary results from laboratory and in situ monitoring. Hydrological Sciences Journal, 58 (4), 912–929. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper examines and assesses predictive methods for the saturated hydraulic conductivity of soils. The soil definition is that of engineering. It is not that of soil science and agriculture, which corresponds to 'top soil' in engineering. Most predictive methods were calibrated using laboratory permeability tests performed on either disturbed or intact specimens for which the test conditions were either measured or supposed to be known. The quality of predictive equations depends highly on the test quality. Without examining all the quality issues, the paper explains the 14 most important mistakes for tests in rigid-wall or flexible-wall permeameters. Then, it briefly presents 45 predictive methods, and in detail, those with some potential, such as the Kozeny-Carman equation. Afterwards, the data of hundreds of excellent quality tests, with none of the 14 mistakes, are used to assess the predictive methods with a potential. The relative performance of those methods is evaluated and presented in graphs. Three methods are found to work fairly well for non-plastic soils, two for plastic soils without fissures, and one for compacted plastic soils used for liners and covers. The paper discusses the effects of temperature and intrinsic anisotropy within the specimen, but not larger scale anisotropy within aquifers and aquitards. [ABSTRACT FROM AUTHOR]

Vers la dernière décennie et suite aux conditions de plus en plus intensives de production hors sol des plants forestiers, l’utilisation d’un substrat de culture dont les propriétés physico-chimiques sont optimales, pour la croissance et la physiologie des plants forestiers lors des différentes phases de croissance en pépinière forestière, s’avère indispensable. Pour avoir un tel substrat, il s’avère nécessaire de caractériser et d’optimiser les paramètres de porosité (teneurs en air et en eau) et la richesse initiale du substrat en éléments minéraux. Le recours au digestat particulièrement le Méthacompost Avicole (MCA), qui est la fraction solide du digestat issu de la biométhanisation des fientes avicoles, en remplacement partiel du Compost Sylvicole Brut (CSB) formant le substrat de référence pour la production des plants forestiers pourrait constituer une alternative très prometteuse. La présente étude a pour objectif d’évaluer la qualité du CSB et les possibilités d’amélioration de ses propriétés physico-chimiques, en le mélangeant avec le Méthacompost Avicole Affiné à la sortie du digesteur (MCAdig) ou à la sortie du décanteur (MCAdéc). A cet effet, des tests de porosité et des analyses chimiques de substrats confectionnés ont été effectués. [ABSTRACT FROM AUTHOR]

The aim of this study is to analyze the relationship between scaling resistance and sorptivity of concrete surfaces. Five types of air-entrained concretes containing cementitious materials (25%-35% fly ash, 25-35 slag, 1%-2% silica fume) were submitted to scaling tests according to ASTM C672 procedure, after 14 and 28 days of moist curing. These concretes were also submitted to sorptivity testing. Results show a clear correlation between scaling test results and sorptivity measurements. Low surface sorptivity (<0.1 mm/min1/2) always indicates satisfactory scaling resistance. These results show that to obtain adequate scaling resistance, curing conditions and mix design must be optimized to promote the development of a dense and impervious concrete skin that resists external water penetration. Lengthening of the moist-curing period of concrete incorporating cementitious materials systematically decreases sorptivity and improves its scaling resistance, especially for concrete containing fly ash. [ABSTRACT FROM AUTHOR]

The rail assembly is generally done through an aluminothermic welding process. This process involves the casting of solder between the two rail ends to be assembled. The quality of this assembly is highly dependent on conditions during the realization that are usually difficult to meet. Indeed, conventional techniques for the control of rails are often shown as the presence of welding defects in the junction. The observations suggest that these defects are mainly of two types: defects of adhesion (or bonding defects) and porosity defects (or multiple blisters defects). Each of these defects may constitute a privileged site of stress concentration. Depending on the level of these stresses, potential damage process may be developed and put off the rail. It therefore seems necessary to model the mechanical behavior of these welds with these defects in order to classify them by their criticality. In this study, we therefore modeled with the same load and with the same boundary conditions, the weld seam for each type of defect. The results are very conclusive and can well guide the deepening of our analysis side welding parameters. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: The Soultz Enhanced Geothermal System (EGS) reservoir''s response to chemical stimulation is assessed by numerical simulation of coupled thermo-hydraulic-chemical processes. To assess chemical interactions between host rocks and a mixture of HCl and HF as well as its potential effects on the Soultz EGS reservoir, new modelling efforts using the FRACHEM code have been initiated. This article presents the model calibration and results. Simulations consider realistic conditions with available data sets from the EGS system at Soultz. Results indicate that the predicted amount of fracture sealing minerals dissolved by injection of a mixture of acids Regular Mud Acid (RMA) was consistent with the estimated amount from the test performed on GPK4 well at Soultz EGS site. Consequently reservoir porosity and permeability can be enhanced especially near the injection well by acidizing treatment. [Copyright &y& Elsevier]

Abstract: In EGS projects, fault zones are considered as the structures controlling deep flow at the reservoir scale. Using a large set of petrophysical properties (porosity, density, permeability, thermal conductivity [TC]) measured on cores collected along the EPS-1 borehole, a model of fault zone is proposed to describe them. A fault zone is a complex structure, showing different parts with different kinds of deformations and/or materials that could explain chemical and physical processes observed during fluid-rock interactions. The different parts composing the fault zone are: (1) the fault core or gauge zone; (2) the damage zone; (3) and the protolith. They are usually heterogeneous and show different physical properties. The damage zone is a potential high permeability channel and could become the main pathway for fluids if secondary minerals seal the fault core. Porosity is the lowest within the protolith, between 0.5 and 1%, but can go up to 15% in the fault zone. Permeability ranges from 10−20 m2 in the fresh granite to, at least, 10−15 m2 in the fault core, and TC ranges from 2.5WK−1m−1 to 3.7WK−1m−1. Finally, variations in specific surface are set over two orders of magnitude. If the lowest values usually characterize the fresh granite far from fault zones, physical properties could show variations spread over their whole respective ranges within these fault zones. [Copyright &y& Elsevier]

Copyright of Dairy Science & Technology (Springer Science & Business Media B.V.) is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

If natural windbreaks create air turbulence and can help disperse odours from livestock operations, their dispersion effect has not been extensively researched. This paper introduces a model simulating odour dispersion downwind from natural windbreaks. The standard k-ε model of the FLUENT software was used to incorporate the effect of climatic conditions and windbreak structure. The model was calibrated for wind velocity recovery, odour concentration (OC) from field observations and inertial resistance. Once calibrated, the model accurately reproduced the odour plume developing downwind from the windbreak. The correlation between OC for 11 field trials and that simulated were statistically significant (P < 0.01), indicating that the model was accurate. The model demonstrated that a windbreak did alter the magnitude and direction of the wind velocity, thus creating a pressure jump across its width. This pressure jump produces a strong downwind turbulence forming a mixing layer capable of enhancing odour dispersion. [ABSTRACT FROM AUTHOR]

Abstract: Acoustic P and S wave propagation in the argillaceous sediments is related to the media porosity as well as on clay-mineral composition. The propagation-velocity prediction of these waves thus requires knowledge of these two parameters and their impact on the velocities. Porosity decreasing with effective pressure increasing, due to the burial, follows an exponential law. We will limit our analysis to the three clays: kaolinite, illite and montmorillonite. The variations of porosity between various clays are strongly reduced with the increase in effective pressure, which tends to minimize the impact of mineralogy with the burial. By integrating these equations in a model of Reuss and Voigt, in which we consider an association mineral argillaceous/fluid, we extract a law of evolution for bulk and shear moduli of clay according to the pressure, for each type of clay. By associating clay moduli calculation results to qualitative and quantitative predictions from spectral nuclear-radiations tools and X-ray-diffraction measurements on cores, it is possible to predict sonic velocities in clays with a given effective pressure. An example of P and S velocity modelling is presented on a well in the deep offshore-turbiditic environment. [Copyright &y& Elsevier]

The ultraviolet induced fluorescence signatures of various petroleum products were evaluated in different soils to examine the impact of soil type, grain size, porosity, and mineralogy. The different soil matrices induced changes to the spectral features of petroleum hydrocarbon fluorescence excitation-emission matrices (EEMs). Once the effect of the soil matrix was characterized, fluorescence EEMs were analyzed using parallel factor analysis (PARAFAC) and soft independent method of class analogy (SIMCA) to identify the petroleum products and their underlying aromatic hydrocarbon components. For quantitative analysis, total fluorescence values obtained from fluorescence EEMs of analyzed petroleum products were used to estimate their concentrations in different soil matrices. Results indicated that this approach provides identifying fingerprinting and reasonable estimate of concentrations for a number of petroleum products in different soils matrices. [ABSTRACT FROM AUTHOR]

Abstract: Stone substitution is a conventional operation during heritage buildings’ restoration, but becomes problematic for architects and restorers when the quarry is mined out. The compatibility of the substitution stones with the original ones has been for long mainly based on the aesthetical aspect, this resulting too often in a patchwork of original and substitution stones with different patina after several years because of differences of properties. In this study, the objective is to show how substitution stones can be selected by combining aesthetic criteria and stones properties that are relevant for analyzing their compatibility. A couple of French limestones with their potential substitution stones were selected for the study. Our results showed that potential substitution stones selected on their aesthetic criteria require to be rejected because of their differences of physical properties. On the other hand, our results showed also the possibility to select substitution stones with satisfactory aesthetic aspect and properties that enable to expect a satisfactory compatibility with the original stone. [Copyright &y& Elsevier]

Abstract: NMR investigations of plant biopolymers, from the molecule to the supramolecular organisation. Various NMR techniques have been used to characterize plant biopolymers, isolated or in interaction with other macromolecules in complex composites. In our investigations, 1H and 13C NMR spectroscopy is used to study, at the molecular scale, complex biochemical processes as those involved during fruit ripening. NMR informs also about the fine structure of biopolymers, about their polymorphism and their crystallinity. At supramolecular scales, measurements of self-diffusion coefficients complement the low-field relaxometry approaches in order to estimate pore sizes in composite systems of biopolymers. [Copyright &y& Elsevier]

Copyright of Materials & Structures is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Performance of dry-cast concrete masonry products (DCCMPs), which are becoming the product of choice for many applications, has yet to be assessed in a comprehensive manner. This study was undertaken to investigate the effects of mix design and manufacturing parameters on the mechanical and transport properties, as well as the freeze–thaw (F/T) durabilities, of DCCMPs. The variables studied were water to cement ratio, mixing time, vibration time, and curing regime. Freeze–thaw durability was assessed in accordance with the American Society for Testing and Materials (ASTM) standard C1262 by exposing specimens to four conditions: water, 3% NaCl, 4% CaCl2, and 4% MgCl2 solutions. Results revealed that 3% NaCl exposure yielded the most mass loss due to scaling, whereas 4% MgCl2 exposure exhibited the least. Increase in either water content, vibration time, mixing time, or use of moist curing led to improvement in the mechanical properties, refinement of large pores in the range of 40 to 400 μm, reduction of total porosity, and enhancement of F/T durability of capstones. Ionic sorptivity yielded a strong statistical correlation with mass loss due to F/T action in the presence of 3% NaCl and 4% CaCl2. [ABSTRACT FROM AUTHOR]

Screens can be utilized efficiently for dissipating energy of water. In this study, water flowing beneath a gate is used to simulate the flow downstream of a small hydraulic structure, and vertically placed screens are used as an alternative tool for energy dissipation. Investigations are conducted using a series of experiments. The porosity, thickness, and location of the screens are the major parameters together with the Froude number of the upstream flow. The experiments cover a range of supercritical Froude numbers between 5.0 and 18.0, porosities between 20% and 60%, and screen locations up to 100 times the undisturbed upstream flow depth. The thicknesses of the screens used are in the order of the undisturbed upstream flow depth. The results show the importance of each parameter in the energy-dissipating performance of the screens and the system. It is observed that screens dissipate significantly more energy than a conventional hydraulic jump within the large range of Froude numbers covered in the study. The results are also in agreement with the results of an earlier similar study. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)