Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
See detailEffect of encapsulated nanoparticles on thermophillic anaerobic digestion
Al-Ahmad, Alaa Eddin ULg; Hiligsmann, Serge ULg; Lambert, Stéphanie ULg et al

Poster (2014, February 07)

Recently, enormous interest has been focused on biological applications of metal nanoparticles NPs due to their small size, high specified surface and their great potential in application to many science ... [more ▼]

Recently, enormous interest has been focused on biological applications of metal nanoparticles NPs due to their small size, high specified surface and their great potential in application to many science fields. The most studied process concerns zero valent palladium and iron NPs improving anaerobic biodegradation of chlorinated hydrocarbons (Windt et al., 2005). Moreover, investigation carried out in our lab showed that iron NPs encapsulated in silicate matrix may enhance hydrogen production by Clostridium butyricum (Beckers et al., 2013). Nevertheless the influences of metal NPs on methane producing anaerobic digestion have seldom been investigated. The present work investigates the enhancement effect of seven different metal NPs on methane production during the thermophilic anaerobic digestion. NPs of Cu, Pd, Pt, Ni, Co, Ag and Fe encapsulated in porous silica (SiO2) to prevent their coagulation and agglomeration, were added at concentration of 10-5mol/L in batch test (125ml serum bottles containing 70mL culture medium with 5g/L acetate monohydrate as the sole carbon substrate). Nickel, cobalt and iron NPs improved methane production from acetate. To confirm the previous results, the NPs were tested at different concentrations (10-4, 10-5, and 10-6 mol/L) with starch and glucose substrates. The results show that the impact increases with the increase of NPs concentrations up to 10-4 mol/L. The modified Gompertz equation was applied to describe the effect of NPs on anaerobic digestion. According to this model, the kinetic of methane production was particularly affected by nanoparticles addition. The values of the maximum methane production rate MPR (ml/day) was significantly higher 72.5% with nickel NPs at a concentration of 10-4 mol/L than the control without NPs. [less ▲]

Detailed reference viewed: 178 (31 ULg)
Full Text
Peer Reviewed
See detailEffect of end connection restraints on the stability of steel beams in bending
Amara, S.; Kerdal, D. E.; Jaspart, Jean-Pierre ULg

in Advanced Steel Construction (2008)

The influence of the end restraint conditions on the lateral-torsional buckling of beams is investigated in detail using finite element method. The paper focuses on the limitation of Eurocode 3 regarding ... [more ▼]

The influence of the end restraint conditions on the lateral-torsional buckling of beams is investigated in detail using finite element method. The paper focuses on the limitation of Eurocode 3 regarding the lateral bending and torsional restraint coefficients kz and kθ of the end supports. Theoretical expressions of the coefficients kz and kθ taking into account the minor axis flexural restraint at the support and the end torsional restraint respectively are presented. The introduction of new coefficients zk and kθ representing the actual support conditions in the expression of the elastic critical moment is suggested. A comparison between the elastic critical moments for various beam cross-sections, lengths and various end restraints, obtained from the finite-element method, and those derived from EC3 ENV method, in which the proposed coefficients zk and kθ are introduced, confirms the reliability of these coefficients that model the end support conditions. [less ▲]

Detailed reference viewed: 201 (10 ULg)
Full Text
Peer Reviewed
See detailEffect of endogenous serotonin on the binding of the 5-HT1A PET ligand 18 F in the rat hippocampus: kinetic b measurements combined with microdialysis
Zimmer, Luc; Mauger, Gweltas; Le Bars, Didier et al

in Journal of Neurochemistry (2002), 80(2), 278-286

By using a combination of an original beta(+)-sensitive intracerebral probe and microdialysis, the effect of increased endogenous serotonin on specific binding of F-18-MPPF [4-(2'-methoxy-phenyl)-1-[2'-[N ... [more ▼]

By using a combination of an original beta(+)-sensitive intracerebral probe and microdialysis, the effect of increased endogenous serotonin on specific binding of F-18-MPPF [4-(2'-methoxy-phenyl)-1-[2'-[N-(2"-pyridinyl)-p-fluorobenzamido]ethyl]piperazine] to the serotonin-1A (5-HT1A) receptors was investigated in the hippocampus of the anaesthetized rat. Our beta-sensitive probe prototype was sensitive enough to obtain Specific F-18-MPPF time-activity curves in the rodent (hippocampus/cerebellum ratio approximate to 2). The serotonin neuronal release was pharmacologically enhanced using fenfluramine at three different doses (1, 2 and 10 mg/kg intravenous) multiplying by 2-15 the extracellular serotonin in the hippocampus. These extracellular variations of extracellular serotonin resulted in dose-ranging decreases in F-18-MPPF-specific binding in the same rat. Our results showed for the first time that F-18-MPPF binding could be modulated by modifications of extracellular serotonin in the rat hippocampus. These results were confirmed by the enhancement of extracellular radioactivity collected in dialysates after the displacement of F-18-MPPF by fenfluramine. After modelization, F-18-MPPF binding could constitute an interesting radiotracer for positron emission tomography in evaluating the serotonin endogenous levels in limbic areas of the human brain. [less ▲]

Detailed reference viewed: 14 (1 ULg)
Peer Reviewed
See detailEffect of endotoxin insult on critical closure in the canine pulmonary vasculature
D'Orio, Vincenzo ULg; FATEMI, M; MENDES, P et al

in Applied Cardiopulmonary Pathophysiology [=ACP] (1992), 4

Detailed reference viewed: 16 (0 ULg)
Peer Reviewed
See detailEffect of energy under- and protein normonutrition in the fattening of Belgian Blue double muscled cull cows
Cremer, Véronique; Cabaraux, Jean-François ULg; Hornick, Jean-Luc ULg et al

in Book of abstracts of the 51st Annual Meeting of the European Association for Animal Production (2000)

Detailed reference viewed: 16 (1 ULg)
See detailEffect of energy under- and protein overnutrition on meat deposition in cull cows
Van Eenaeme, Christian ULg; Hornick, Jean-Luc ULg; Raskin, Pascale et al

in Book of abstracts of the 49th annual meeting of the European association for animal production (1998)

Detailed reference viewed: 56 (0 ULg)
Full Text
Peer Reviewed
See detailEffect of Enrofloxacin Therapy on Shipping Fever Pneumonia in Feedlot Cattle
Lekeux, Pierre ULg; Art, Tatiana ULg

in Veterinary Record : Journal of the British Veterinary Association (1988), 123(8), 205-207

The effect of enrofloxacin therapy was investigated in 110 male double-muscled cattle weighing 275 +/- 3 kg, during a spontaneous outbreak of shipping fever occurring 11 +/- 2 days after they arrived in ... [more ▼]

The effect of enrofloxacin therapy was investigated in 110 male double-muscled cattle weighing 275 +/- 3 kg, during a spontaneous outbreak of shipping fever occurring 11 +/- 2 days after they arrived in the feedlot. Forty-six diseased animals were divided randomly into three groups A, B and C, containing 17, 19 and 10 animals, respectively; the animals in group A were injected intramuscularly once daily for three consecutive days with 2.5 mg/kg of enrofloxacin, those in group B with 5 mg/kg of enrofloxacin and those in group C with 10 mg/kg of oxytetracycline. Clinical, serological, production and respiratory functional observations were recorded. The animals were clinically cured after the three day treatment except for three in group A and two in group C. These five animals made a clinical recovery after a three day booster treatment with a dose of 5 mg/kg enrofloxacin. The changes in respiratory gas exchange values induced by shipping fever were completely reversed 15 days later, suggesting that there had been no irreversible lung damage. The daily weight gains and the arterial blood gas values of the three groups of treated cattle were not significantly different. The high efficacy of the low dosage of enrofloxacin in this clinical syndrome may be explained by its antibacterial activity against Pasteurella species and Mycoplasma species. This field trial supports the in vitro studies which suggested than enrofloxacin is an appropriate therapy in cases of shipping fever. [less ▲]

Detailed reference viewed: 50 (0 ULg)
Full Text
Peer Reviewed
See detailEffect of entomopathogenic Aspergillus strains against the pea aphid, Acyrthosiphon pisum (Hemiptera: Aphididae)
Seye, Fawrou; Bawin, Thomas ULg; Boukraa, Slimane ULg et al

in Applied Entomology and Zoology (2014)

Aphids (Homoptera: Aphididae) are sap-sucking insect pests that feed on several plants of agronomical importance. Entomopathogenic fungi are valuable tools for potential aphid control. As part of a ... [more ▼]

Aphids (Homoptera: Aphididae) are sap-sucking insect pests that feed on several plants of agronomical importance. Entomopathogenic fungi are valuable tools for potential aphid control. As part of a selection process, laboratory bioassays were carried with five different concentrations of Aspergillus clavatus (Desmazières), Aspergillus flavus (Link) and Metarhizium anisopliae ((Metschnikoff) Sorokin) spores against the pea aphid, Acyrthosiphon pisum (Harris). Aspergillus isolates induced higher mortalities than M. anisopliae which is a well-known entomopathogen in the literature. Lethal concentrations (LC50 and LC90) were 1.23 x 10^3 and 1.34 x 10^7 spores/ml for A. flavus, 4.95 x 10^2 and 5.65 x 10^7 spores/ml for A. clavatus, and 3.67 x 10^3 and 9.71 x 10^7 spores/ml for M. anisopliae five days after treatment. Mycelia development and sporulation on adult cadavers was observed 48 hours after incubation. The intrinsic growth rate of A. pisum decreased with increased spore concentration for all fungal strains suggesting an increase in pathogen fitness related to a consumption of host resources. In conclusion, Aspergillus species could be useful in aphid control as pest control agents despite their saprophytic lifestyle. This is also in our knowledge the first report of A. clavatus and A. flavus strains pathogenic to aphids. [less ▲]

Detailed reference viewed: 78 (33 ULg)
Peer Reviewed
See detailEffect of environmental factors on the interaction plant-pathogen-Bacillus amyloliquefaciens S499
Pertot, I.; Hosni, T.; Pedrotti, L. et al

Conference (2011)

Detailed reference viewed: 25 (6 ULg)
Full Text
Peer Reviewed
See detailEffect of environmental factors on the interaction plant-pathogen-Bacillus amyloliquefaciens S499
Pertot, I.; Hosni, T.; Pedrotti, L. et al

in Bulletin OILB/SROP = IOBC/WPRS Bulletin (2012), sous presse

Detailed reference viewed: 42 (4 ULg)
Full Text
Peer Reviewed
See detailEffect of Environmental Temperature and Relative Humidity on Breathing Pattern and Heart Rate in Ponies During and after Standardised Exercise
Art, Tatiana ULg; Lekeux, Pierre ULg

in Veterinary Record : Journal of the British Veterinary Association (1988), 123(11), 295-299

A preliminary study attempted to assess the influence of atmospheric conditions on the breathing pattern of ponies. The respiratory airflow, tidal volume, breathing frequency, minute volume, total ... [more ▼]

A preliminary study attempted to assess the influence of atmospheric conditions on the breathing pattern of ponies. The respiratory airflow, tidal volume, breathing frequency, minute volume, total pulmonary resistance and heart rate of five ponies (257 +/- 9 kg and three to five years old) were measured by a standardised procedure. Data were collected at rest, during a nine minute period of treadmill exercise and during a five minute recovery period. The ambient temperature (degrees C) and relative humidity (%) were recorded at the time of each investigation and the respiratory parameters were divided into two groups according to whether the sum of these measurements was less than 85, ie, the conditions were cold and dry or greater than 85, ie, the conditions were relatively hot and humid. Data for each pony in both conditions were compared. The ambient temperature and relative humidity did not significantly modify the breathing pattern of the ponies either at rest or during exercise. On the other hand the frequency of breathing was significantly higher and the tidal volume and total pulmonary resistance were significantly lower during recovery in hot and humid conditions than in cold and dry conditions, while the minute volume remained unchanged. It was concluded that, during recovery, environmental conditions may modify the breathing pattern of horses. This suggests that in hot and humid weather conditions the respiratory rate may be an unreliable measure of the fitness of a horse and, consequently, that a more complete pulmonary investigation should be undertaken for an assessment of fitness. [less ▲]

Detailed reference viewed: 40 (2 ULg)
Full Text
Peer Reviewed
See detailEffect of enzymatic treatment on rheological properties, glass temperature transition and microstructure of date syrup
Abbès, Fatma; Masmoudi, Manel; Kchaou, Wissal et al

in LWT - Food Science and Technology (2015), 60

A knowledge of rheological properties is of importance in processing, handling, process design, product development and quality control. This study investigates the effect of commercial hydrolytic enzymes ... [more ▼]

A knowledge of rheological properties is of importance in processing, handling, process design, product development and quality control. This study investigates the effect of commercial hydrolytic enzymes (pectinase and cellulase) on rheological properties and glass temperature transition of date syrup. Date syrups obtained by enzymatic extraction exhibited a quasi Newtonian behaviour. The enzyme-treated date syrups showed the highest values of activation energy (Ea). Therefore, these syrups showed the most temperature dependency. Dynamic shear results revealed viscous behaviour for date syrups indicating that both syrups displayed liquid-like behaviour. Temperature significantly affected both (G') and (G''). The glass transition temperature (Tg) of date syrups varied between -39.56 and -45.74 °C depending on their composition. Glass transition temperature of date syrups decreased linearly with an increase in water content. [less ▲]

Detailed reference viewed: 18 (1 ULg)
Full Text
Peer Reviewed
See detailEffect of Epidural Bupivacaine on the Relationship between the Bispectral Index and End-Expiratory Concentrations of Desflurane
Hans, Pol ULg; Lecoq, Jean-Pierre; Brichant, Jean-François ULg et al

in Anaesthesia (1999), 54(9), 899-902

We compared the relationship between the bispectral index and end-tidal desflurane concentrations in 20 patients undergoing elective surgery. Patients received epidurally either 10 ml saline (group S) or ... [more ▼]

We compared the relationship between the bispectral index and end-tidal desflurane concentrations in 20 patients undergoing elective surgery. Patients received epidurally either 10 ml saline (group S) or 10 ml bupivacaine 0.125% with epinephrine 1/800 000 (group B) before induction of anaesthesia with sufentanil (0.15 microgram.kg(-1)) and propofol (2 mg.kg(-1)); muscle relaxation was obtained with cisatracurium (0.2 mg.kg(-1)). Patients lungs were ventilated to maintain end-tidal desflurane at 3% in O2/N2O (50/50) until 5 min after skin incision, followed by two consecutive 10 min periods at end-tidal desflurane 6% and 9%. bispectral index values were recorded before induction, at 3% desflurane before and 5 min after skin incision, and at 6% and 9% end-tidal desflurane. Bispectral index decreased with increasing end-tidal desflurane concentration (ANOVA: p < 0.05). The decrease in bispectral index was significant between pre-induction, 3% and 6% desflurane. No significant difference was observed at 3% desflurane before and after skin incision, or between 6 and 9% desflurane. The relationship between bispectral index and end-tidal desflurane concentration was fitted by a linear regression in each group. No significant difference in bispectral index was observed between the groups at any time. We conclude that bispectral index decreases with increasing desflurane concentration and that this relationship is not affected by epidural 0.125% bupivacaine. [less ▲]

Detailed reference viewed: 18 (8 ULg)
Peer Reviewed
See detailEffect Of Erucic-Acid On The Polymorphism Of Hydrogenated Rapeseed Oil
Cossement, M.; Michaux, M.; Lognay, Georges ULg et al

in Fett : Zeitschrift für Wissenschaft und Technologie der Fette, Öle und Wachse = Lipid : Journal for Science and Technology of Fats, Oils and Waxes (1990), 92(6), 229-231

The polymorphism of rapeseed oils with high and low erucic acid content was investigated using differential scanning calorimetry and X-ray diffraction. Both oils were hydrogenated to various iodine values ... [more ▼]

The polymorphism of rapeseed oils with high and low erucic acid content was investigated using differential scanning calorimetry and X-ray diffraction. Both oils were hydrogenated to various iodine values. The fatty acid pattern showed that erucic acid is slowly saturated. The melting curves were followed by DSC and pulsed NMR. For low iodine value the low erucic acid rapeseed oil exhibits a second melting peak owing to the appearance of new triglycerides with different properties. Samples of hydrogenated rapeseed oils were aged at 20°C and 29°C. The short spacings determinations indicate that the β' [RIGHTWARDS ARROW] β transition is faster for the low erucic acid rapeseed oil (LEAR) than for the high erucic acid rapeseed oil (HEAR). [less ▲]

Detailed reference viewed: 23 (4 ULg)
Full Text
Peer Reviewed
See detailEffect of estradiol supplementation on superovulation in swamp buffalo
Uoc, N. T.; Nguyen, B. X.; Ty, L. V. et al

in Theriogenology (1992), 38(3), 471-478

The effect of estradiol-17β (E2) supplementation on superovulation with (PMSG) or (FSH) was investigated in Swamp buffalo. Sixty-eight buffalo were treated in seven groups. Group 1 served as control and ... [more ▼]

The effect of estradiol-17β (E2) supplementation on superovulation with (PMSG) or (FSH) was investigated in Swamp buffalo. Sixty-eight buffalo were treated in seven groups. Group 1 served as control and was superovulated by standard PMSG or FSH treatment used in routine bovine embryo transfer protocols. Group 2 was superovulated by standard PMSG regimen plus two injections of E2 at a 48 h interval beginning one day before the onset of gonadotropin treatment (short-term supplementation) for a total dosage of 2.5 mg E2; Groups 3 and 4 received the same regimen as Group 2, but in doses of 5.0 and 7.5 mg E2, respectively. Group 5 received the standard FSH regimen (40% LH). Group 6 received short-term E2 (7.5 mg) supplementation of FSH-p. Group 7 was superovulated by standard FSH regimen (40% LH) plus three injections of E2 at 48–72 h intervals beginning five days before the onset of gonadotropin treatment (long-term supplementation) for a total dosage of 7.5 mg E2. The number of corpora lutea (CL) and follicles ≥ 8 mm in diameter were recorded by palpation per rectum and after slaughter. The mean numbers of CL and follicles were 0.99, 5.8, 8.0, 10.6, 4.0, 3.9, 8.1 and 0.25, 6.8, 6.2, 6.2, 1.6, 0.0, 4.1 for Groups 1, 2, 3, 4, 5, 6, 7, respectively. In Group 7, the rates of nonsurgical and postmortem embryo recovery were 46 and 90.4%, respectively and 54.4% of the collected ova were fertilized. These results indicate the possibility of producing viable embryos in buffalo by using E2 supplementation for the gonadotropin treatment. [less ▲]

Detailed reference viewed: 45 (4 ULg)
Full Text
Peer Reviewed
See detailEffect of eutrophication on air-sea CO2 fluxes in the coastal Southern North Sea: a model study of the past 50 years
Gypens, N.; Borges, Alberto ULg; Lancelot, C.

in Global Change Biology (2009), 15(4), 1040-1056

The RIVERSTRAHLER model, an idealized biogeochemical model of the river system, has been coupled to MIRO-CO2, a complex biogeochemical model describing diatom and Phaeocystis blooms and carbon and ... [more ▼]

The RIVERSTRAHLER model, an idealized biogeochemical model of the river system, has been coupled to MIRO-CO2, a complex biogeochemical model describing diatom and Phaeocystis blooms and carbon and nutrient cycles in the marine domain, to assess the dual role of changing nutrient loads and increasing atmospheric CO2 as drivers of air–sea CO2 exchanges in the Southern North Sea with a focus on the Belgian coastal zone (BCZ). The whole area, submitted to the influence of two main rivers (Seine and Scheldt), is characterized by variable diatom and Phaeocystis colonies blooms which impact on the trophic status and air–sea CO2 fluxes of the coastal ecosystem. For this application, the MIRO-CO2 model is implemented in a 0D multibox frame covering the eutrophied Eastern English Channel and Southern North Sea and receiving loads from the rivers Seine and Scheldt. Model simulations are performed for the period between 1951 and 1998 using real forcing fields for sea surface temperature, wind speed and atmospheric CO2 and RIVERSTRAHLER simulations for river carbon and nutrient loads. Model results suggest that the BCZ shifted from a source of CO2 before 1970 (low eutrophication) towards a sink during the 1970–1990 period when anthropogenic DIN and P loads increased, stimulating C fixation by autotrophs. In agreement, a shift from net annual heterotrophy towards autotrophy in BCZ is simulated from 1980. The period after 1990 is characterized by a progressive decrease of P loads concomitant with a decrease of primary production and of the CO2 sink in the BCZ. At the end of the simulation period, the BCZ ecosystem is again net heterotroph and acts as a source of CO2 to the atmosphere. R-MIRO-CO2 scenarios testing the relative impact of temperature, wind speed, atmospheric CO2 and river loads variability on the simulated air–sea CO2 fluxes suggest that the trend in air–sea CO2 fluxes simulated between 1951 and 1998 in the BCZ was mainly controlled by the magnitude and the ratio of inorganic nutrient river loads. Quantitative nutrient changes control the level of primary production while qualitative changes modulate the relative contribution of diatoms and Phaeocystis to this flux and hence the sequestration of atmospheric CO2. [less ▲]

Detailed reference viewed: 86 (4 ULg)
Full Text
Peer Reviewed
See detailEffect of evolutionary miniaturization on the tempo and mode of diversification - An example from marine angelfishes
Frederich, Bruno ULg; Santini, Francesco; Konow, Nicolai et al

Conference (2015, October 09)

Evolutionary change in body size is a widespread phenomenon in animals. Numerous studies have highlighted evolutionary miniaturization, referring to the evolution of small body size, in various taxa. As ... [more ▼]

Evolutionary change in body size is a widespread phenomenon in animals. Numerous studies have highlighted evolutionary miniaturization, referring to the evolution of small body size, in various taxa. As other traits shift, decrease in size can be viewed as a morphological novelty that enables colonization of new “adaptive zones” and subsequent diversification (i.e. a “key innovation”). Thus, evolution to small body size is hypothesized to influence lineage, morphological and ecological diversification. Until now, few studies have tested this hypothesis and current supports are mixed. Here, we present a quantitative analysis of the radiation of Pomacanthidae (angelfishes), an iconic coral reef fish family where small taxa, the so called “pygmy angelfishes” of the genus Centropyge, appear to have evolved three-times. If an evolutionary decrease in size has acted as a key innovation during the evolutionary history of Pomacanthidae, we predict that diversification rates would be the highest in clades of pygmy angelfishes. We produced a time-calibrated phylogeny including 67 species, collected ecological data and quantified the body shape of 80 species using geometric morphometrics. Then, we tested the prediction by modelling macroevolutionary dynamics of diversification using the Bayesian Analysis of Macroevolutionary Mixture (BAMM) framework. BAMM results do not support a common macroevolutionary regime for every pigmy angelfish clades. Only the clade Centropyge Xiphypops shows higher rates of lineage and morphological diversification than the other clades of angelfishes. We show that miniaturization has few effects on the rate of diversification. The shifts in the tempo of diversification observed in C. Xiphypops might instead be related to a functional innovation of the feeding apparatus. Using the Pomacanthidae, we illustrate that miniaturization may not be a main factor in triggering increased of diversification rates at the family level. [less ▲]

Detailed reference viewed: 72 (0 ULg)
Full Text
Peer Reviewed
See detailEffect of excavation induced fractures on radionuclide migration through the Boom Clay (Belgium)
Huysmans, Marijke; Berckmans, Arne; Dassargues, Alain ULg

in Applied Clay Science (2006), 33(3-4), 207-218

In Belgium, the Boom Clay is being evaluated as a potential host formation for the disposal of high-level nuclear waste. In order to investigate this option, an underground research facility composed of ... [more ▼]

In Belgium, the Boom Clay is being evaluated as a potential host formation for the disposal of high-level nuclear waste. In order to investigate this option, an underground research facility composed of two access shafts and 200m of galleries was excavated. Excavation induced fractures were observed in a zone of approximately 1 m around the galleries. In this study, the potential effect of these fractures on radionuclide migration in the Boom Clay is investigated. Therefore, a hydrogeological model of the clay is built with a radionuclide source in the middle of the clay layer surrounded by different fracture configurations. Two types of fracture configurations are inserted in the model. The first type of fracture properties is drawn stochastically from the probability distributions of the properties of the fractures observed around previously excavated galleries. These fracture patterns are considered to be realistic although in this study it is conservatively assumed that no self-sealing occurs. The model is run for a large number of stochastically drawn fracture configurations and the results are compared to a model without fractures. These calculations show that the radionuclide fluxes through the clay are not significantly influenced by these fractures. For the second type of fracture configurations, the fracture properties are varied over a much larger range. Hypothetical fractures with much higher values of fracture extent, aperture, dip and frequency than observed are modeled, With these hypothetical fracture configurations, the critical values of the fracture parameters are determined that must be exceeded to have a significant effect on the radionuclide fluxes through the clay. These calculations show that the extent of the fractured zone has the largest effect on radionuclide migration. The other fracture parameters (aperture, spacing and dip) have a limited effect on the radionuclide fluxes. To obtain a total radionuclide flux through the lower clay boundary that is respectively 10%, 50% and 100% larger than without a fractured zone, the extent of the hypothetical fractured zone should be respectively 27.97 m, 43.86 m and 46.92 m. Such fractures are not expected to be generated by mechanical excavation in the Boom Clay. The obtained critical extent values of the hypothetical fractures are a factor 30 to 40 higher than the measured values of the extent of the excavation disturbed zone. These calculations thus indicate that it is very unlikely that the extent of the fractured zone around the galleries will be large enough to have a significant effect on the radionuclide fluxes through the Boom Clay. This conclusion is further supported by the conservative assumption that no self-sealing occurs. These calculations can function as a preliminary robustness test in ongoing safety analysis studies. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

Detailed reference viewed: 46 (5 ULg)