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See detailDensity and porosity control of sintered 316L stainless steel parts produced by additive manufacturing
Verlee, Bruno; Dormal, Thierry ULg; Lecomte-Beckers, Jacqueline ULg

in Powder Metallurgy (2012), 55(4), 260-267

Additive manufacturing (AM) techniques offer the possibility to build complex geometries with integrated functionalities. Three-dimensional (3D) printing of metallic powder is probably the only AM ... [more ▼]

Additive manufacturing (AM) techniques offer the possibility to build complex geometries with integrated functionalities. Three-dimensional (3D) printing of metallic powder is probably the only AM technique that can build controlled porosity sintered parts, such as filter elements and fluid permeable components. Many building and sintering parameters can be set to adjust porous properties of the final part. The effects of particle size, paricul shape, sintering temperature and sintering time on the final properties of the sinteres parts have been analysed. Correlations have been established between these properties and process parameters [less ▲]

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See detailDensity estimates and nesting-site selection in chimpanzees of the Nimba Mountains, Côte d'Ivoire and Guinea
Granier, Nicolas ULg; Hambuckers, Alain ULg; Matsuzawa, Tetsuro et al

in American Journal of Primatology (2014)

We investigated nesting behavior of non habituated chimpanzees populating the Nimba Mountains to document their abundance and their criterions of nesting-site selection. During a 19-month study we walked ... [more ▼]

We investigated nesting behavior of non habituated chimpanzees populating the Nimba Mountains to document their abundance and their criterions of nesting-site selection. During a 19-month study we walked 80 km of transects and recces each month, and recorded 764 nests (mean group size = 2.23 nests) along with characteristics of vegetation structure and composition, topography and seasonality. Population density estimated with two nest count methods ranged between 0.14 and 0.65 chimpanzee/km2. These values are lower than previous estimates, emphasizing the necessity of protecting remaining wild ape populations. Chimpanzees built nests in 108 tree species out of 437 identified, but 2.3% of total species comprised 52% of nests. Despite they preferred nesting in trees of 25-29 cm DBH and at a mean height of 8.02 m, we recorded an important proportion of terrestrial nests (8.2%) that may reflect a cultural trait of Nimba chimpanzees. A logistic model of nest presence formulated as a function of 12 habitat variables revealed preference for gallery and mountain forests rather than lowland forest, and old-growth forest rather than secondary forests. They nested more frequently in the study area during the dry season (December-April). The highest probability of observing nests was at 770 m altitude, particularly in steep locations (mean ground declivity = 15.54%). Several of the reported nest characteristics combined with the existence of 2 geographically separated clusters of nest, suggest that the study area constitutes the non-overlapping peripheral areas of 2 distinct communities. This nest-based study led us to findings on the behavioral ecology of Nimba chimpanzees, which constitute crucial knowledge to implement efficient and purpose-built conservation. [less ▲]

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See detailDensity Functional Perturbation Theory
Verstraete, Matthieu ULg; Zanolli, Zeila ULg

in Blügel, S.; Helbig, N.; Meden, V. (Eds.) et al Computing Solids: Models, Ab-initio Methods and Supercomputing, Lecture Notes of the 45th Spring School 2014 (2014)

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See detailDensity Functional Perturbation Threory with Spin-Orbit Coupling: the case of Pb
Verstraete, Matthieu ULg; Torrent, M.; Jollet, F. et al

in Physical Review. B : Condensed Matter (2008), 78

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See detailDensity functional theory beyond the linear regime: Validating an adiabatic local density approximation
Helbig, N.; Fuks, J. I.; Casula, M. et al

in Physical Review. A (2011), 83

We present a local density approximation (LDA) for one-dimensional (1D) systems interacting via the soft-Coulomb interaction based on quantum Monte Carlo calculations. Results for the ground-state ... [more ▼]

We present a local density approximation (LDA) for one-dimensional (1D) systems interacting via the soft-Coulomb interaction based on quantum Monte Carlo calculations. Results for the ground-state energies and ionization potentials of finite 1D systems show excellent agreement with exact calculations obtained by exploiting the mapping of an N-electron system in d dimensions onto a single electron in N×d dimensions, properly symmetrized by the Young diagrams. We conclude that 1D LDA is of the same quality as its three-dimensional (3D) counterpart, and we infer conclusions about 3D LDA. The linear and nonlinear time-dependent responses of 1D model systems using LDA, exact exchange, and the exact solution are investigated and show very good agreement in both cases, except for the well-known problem of missing double excitations. Consequently, the 3D LDA is expected to be of good quality beyond the linear response. In addition, the 1D LDA should prove useful in modeling the interaction of atoms with strong laser fields, where this specific 1D model is often used. [less ▲]

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See detailA density functional theory calculation of the electronic properties of several high-spin and low-spin iron(II) pyrazolylborate complexes
Remacle, Françoise ULg; Long, G. J.; Grandjean, Fernande ULg

in Inorganic Chemistry (2008), 47(10), 4005-4014

Density functional theory has been used to study the electronic spin-state properties of low-spin Fe[HB(PZ)(3)](2), lhigh-spin Fe[HB(3-MePZ)(3)](2), high-spin Fe[HB(3,5-Me(2)PZ)(3)](2), and high-spin Fe ... [more ▼]

Density functional theory has been used to study the electronic spin-state properties of low-spin Fe[HB(PZ)(3)](2), lhigh-spin Fe[HB(3-MePZ)(3)](2), high-spin Fe[HB(3,5-Me(2)PZ)(3)](2), and high-spin Fe[HB(3,4,5-Me(3)PZ)(3)](2) complexes that exhibit very different iron(II) electronic spin-sate crossover behaviors with changing temperature and pressure. Excellent agreement is obtained between the experimentally,observed Mossbauer-effect quadrupole splittings and isomer shifts of these complexes and those calculated with the B3LYP functional and various different basis sets for both the high-spin and low-spin states of iron(II). The calculations for Fe[HB(PZ)(3)](2) that use the LANL2DZ, 6-31++G(d,p), and 6-311++G(d,p) basis sets for iron all lead to very similar electric field gradients and thus quadrupole splittings. The initial calculations, which were based upon the known X-ray structures, were followed by structural optimization, an optimization that led to small increases in the Fe-N bond distances. Optimization led to at most trivial changes in the intraligand bond distances and angles. The importance of the 3-methy I-H center dot center dot center dot H-3-methyl nonbonded intramolecular interligand interactions in controlling the minimum Fe-N bond distances and determining the iron(II) spin state both in Fe[HB(3-Mepz)(3)](2) and in the related methyl-substituted complexes has been identified. [less ▲]

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See detailDensity of herbaceous plants and distribution of western gorillas in different habitat types in south-east Cameroon
Willie, Jacob; Petre, Charles-Albert ULg; Tagg, Nikki et al

in African Journal of Ecology (2012), 51

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See detailDensity of states for a specified correlation function and the energy landscape
Gommes, Cédric ULg; Jiao, Yang; Torquato, Salvatore

in Physical Review Letters (2012)

The degeneracy of two-phase disordered microstructures consistent with a specified correlation function is analyzed by mapping it to a ground-state degeneracy. We determine for the first time the ... [more ▼]

The degeneracy of two-phase disordered microstructures consistent with a specified correlation function is analyzed by mapping it to a ground-state degeneracy. We determine for the first time the associated density of states via a Monte Carlo algorithm. Our results are described in terms of the roughness of the energy landscape, defined on a hypercubic configuration space. The use of a Hamming distance in this space enables us to define a roughness metric, which is calculated from the correlation function alone and related quantitatively to the structural degeneracy. This relation is validated for a wide variety of disordered systems. [less ▲]

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See detailDensity of states of chaotic Andreev billiards
Kuipers, Jack; Engl, Thomas; Berkolaiko, Gregory et al

in PHYSICAL REVIEW B (2011), 83(19), 195316-21

Quantum cavities or dots have markedly different properties depending on whether their classical counterparts are chaotic or not. Connecting a superconductor to such a cavity leads to notable proximity ... [more ▼]

Quantum cavities or dots have markedly different properties depending on whether their classical counterparts are chaotic or not. Connecting a superconductor to such a cavity leads to notable proximity effects, particularly the appearance, predicted by random matrix theory, of a hard gap in the excitation spectrum of quantum chaotic systems. Andreev billiards are interesting examples of such structures built with superconductors connected to a ballistic normal metal billiard since each time an electron hits the superconducting part it is retroreflected as a hole (and vice versa). Using a semiclassical framework for systems with chaotic dynamics, we show how this reflection, along with the interference due to subtle correlations between the classical paths of electrons and holes inside the system, is ultimately responsible for the gap formation. The treatment can be extended to include the effects of a symmetry-breaking magnetic field in the normal part of the billiard or an Andreev billiard connected to two phase-shifted superconductors. Therefore, we are able to see how these effects can remold and eventually suppress the gap. Furthermore, the semiclassical framework is able to cover the effect of a finite Ehrenfest time, which also causes the gap to shrink. However, for intermediate values this leads to the appearance of a second hard gap-a clear signature of the Ehrenfest time. [less ▲]

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See detailDensity variations and their influence on carbon stocks: case-study on two Biosphere Reserves in the Democratic Republic of Congo
De Ridder, Maaike; de Haulleville, Thalès ULg; Kearsley, Elizabeth et al

Poster (2014, April 28)

It is commonly acknowledged that allometric equations for aboveground biomass and carbon stock estimates are improved significantly if density is included as a variable. However, not much attention is ... [more ▼]

It is commonly acknowledged that allometric equations for aboveground biomass and carbon stock estimates are improved significantly if density is included as a variable. However, not much attention is given to this variable in terms of exact, measured values and density profiles from pith to bark. Most published case-studies obtain density values from literature sources or databases, this way using large ranges of density values and possible causing significant errors in carbon stock estimates. The use of one single fixed value for density is also not recommended if carbon stock increments are estimated. Therefore, our objective is to measure and analyze a large number of tree species occurring in two Biosphere Reserves (Luki and Yangambi). Nevertheless, the diversity of tree species in these tropical forests is too high to perform this kind of detailed analysis on all tree species (> 200/ha). Therefore, we focus on the most frequently encountered tree species with high abundance (trees/ha) and dominance (basal area/ha) for this study. Increment cores were scanned with a helical X-ray protocol to obtain density profiles from pith to bark. This way, we aim at dividing the tree species with a distinct type of density profile into separate groups. If, e.g., slopes in density values from pith to bark remain stable over larger samples of one tree species, this slope could also be used to correct for errors in carbon (increment) estimates, caused by density values from simplified density measurements or density values from literature. In summary, this is most likely the first study in the Congo Basin that focuses on density patterns in order to check their influence on carbon stocks and differences in carbon stocking based on species composition (density profiles ∼ temperament of tree species). [less ▲]

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See detailDensity-Dependent Reproductive Success In Tribolium Castaneum (Herbst) (Coleoptera : Tenebrionidae)
Assie, L. K.; Brostaux, Yves ULg; Haubruge, Eric ULg

in Journal of Stored Products Research (2008), 44(3), 285-289

Two strains of Tribolium castaneum, one being susceptible to malathion (Asm) and the other malathion-specific resistant (PRm), were used to assess the effect of population density and its interaction with ... [more ▼]

Two strains of Tribolium castaneum, one being susceptible to malathion (Asm) and the other malathion-specific resistant (PRm), were used to assess the effect of population density and its interaction with genetic background in reproductive success. A highly significant allometric relationship between female body weight and fecundity (R2=0.413) and another between female body weight and larval survivorship (R2=0.561) were found. Data showed that population density exerted an indirect effect on the reproductive success. The body weight of the Asm female was not affected by variations in population density but the body weight of the PRm female increased with reduced population density. The genetic background (strain) and/or malathion-specific resistance greatly influenced reproductive success. Concerning the percentage survivorship of offspring of the two strains, there was an opposite trend with increased population density: in PRm, survivorship was lower at high density (76.64±13.75; mean±SD) and higher at low density (88.39±7.61), whereas in Asm, survivorship was higher at high density (53.39±15.57) and lower at low density (43.99±20.08). The PRm female laid more eggs than the Asm. Reproductive success was significantly higher in PRm than in Asm. In addition, the genetic background (the strain) and/or the pleiotropic effect of malathion-specific resistance had a significant effect on the fecundity of PRm because the differences in fecundity and reproductive success between Asm and PRm went beyond the body weight of the female and might be explained by their genetic background and/or the pleiotropic effect of malathion-specific resistance. [less ▲]

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See detailDensity-functional theory of polar insulators
Gonze, X.; Ghosez, Philippe ULg; Godby, R. W.

in Physical Review Letters (1997), 78(2), 294-297

We examine the density-functional theory of macroscopic insulators, obtained in the large-cluster limit or under periodic boundary conditions. For polar crystals, we find that the two procedures are not ... [more ▼]

We examine the density-functional theory of macroscopic insulators, obtained in the large-cluster limit or under periodic boundary conditions. For polar crystals, we find that the two procedures are not equivalent. In a large-cluster case, the exact exchange-correlation potential acquires a homogeneous ''electric field'' which is absent from the usual local approximations, and the Kohn-Sham electronic system becomes metallic. With periodic boundary conditions, such a field ist forbidden, and the polarization deduced from Kohn-Sham wave functions is incorrect even if the exact functional is used. [less ▲]

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See detailDensity-functional theory of the pressure distribution at metal surfaces
Heinrichs, J.; Magain, Pierre ULg

in Physica Status Solidi B. Basic Research (1982), 110

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See detailDENSITY-POLARIZATION FUNCTIONAL THEORY OF THE RESPONSE OF A PERIODIC INSULATING SOLID TO AN ELECTRIC-FIELD
GONZE, X.; Ghosez, Philippe ULg; GODBY, R. W.

in Physical Review Letters (1995), 74(20), 4035-4038

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See detailDental biomaterials
Mainjot, Amélie ULg

Scientific conference (2015, December 08)

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See detailDental ceramics: classification and indications
Mainjot, Amélie ULg

in Esthetics in Dentistry (2016)

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See detailDental extractions in patients treated with intravenous bisphosphonates and risk of osteonecrosis of jaws.
GAUDIN, Elise ULg; HERION, Francine ULg; ROMPEN, Eric ULg et al

Poster (2012, June)

Aim : Dental extraction remains contra-indicated in patients treated with intravenous (IV) bisphosphonates for oncology reasons because of the high risk of bisphosphonate-related osteonecrosis of the jaw ... [more ▼]

Aim : Dental extraction remains contra-indicated in patients treated with intravenous (IV) bisphosphonates for oncology reasons because of the high risk of bisphosphonate-related osteonecrosis of the jaw (BRONJ). The objective of the present abstract was to present a preventive tooth extraction protocol in patients treated with IV bisphosphonates based on the surgical removal of the alveolar process. The second objective was to identify potential risk factors to develop BRONJ. Material and Methods : 17 patients treated with IV bisphosphonate and needing at least a tooth extraction, were included. A standardized extraction protocol was followed, including alveolectomy of at least 50% of the alveolar process, pre and post-operative antibiotherapy was administrated. The patients were followed for a mean period of 29 months (min:3 -max:62). Results : In all, 17 patients and 22 extraction sites mandible (15), maxilla (7) were involved in the study. No signs of inflamed tissue or necrotic exposed bone in any patient were observed during the follow-up period and the level of comfort for the patient was improved in all cases. Nevertheless, when a careful screening of the healing area was made using a probe, in 4 out of 22 (18,2%) sites, a remaining bone contact was found and appeared to be related location (mandible), duration of biphosphonate treatment and to concomitant. Conclusion : The present cases series suggests that the described extraction protocol in IV biphosphonate patients allowed 100% bone healing and complete soft tissues healing in 81.8% of the extraction sites.The sites that have not fully recovered seemed to be related to different factors. [less ▲]

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See detailDental occlusion influences knee muscular performances in asymptomatic females.
GROSDENT, Stéphanie ULg; O'Thanh, Roseline; Domken, Olivier et al

in Journal of strength and conditioning research / National Strength & Conditioning Association (2014), 28(2), 492498

Some authors claim that occlusal appliances can enhance athletic performance. Therefore this study investigated the influence of dental occlusion on knee muscle strength performance. Twelve healthy female ... [more ▼]

Some authors claim that occlusal appliances can enhance athletic performance. Therefore this study investigated the influence of dental occlusion on knee muscle strength performance. Twelve healthy female subjects (mean age 24.1 +/- 3.1 years) without temporomandibular joint dysfunction participated in this study. Isokinetic quadriceps and hamstring strength were assessed in relation to three randomized jaw conditions: mouth closed in maximum intercuspidation without splint, mouth closed on a balanced splint which optimized contact over the dental arch, mouth closed on a piece of resin of 1 mm which created an imbalanced occlusion. Tests were performed at 60 degrees /s and 240 degrees /s in concentric and 30 degrees /s in eccentric exertions. Concentric performances did not show any significant difference between the 3 jaw conditions (p > 0.05). By contrast, in the eccentric trials related to quadriceps performance, significant differences (p < 0.05) were observed between the resin condition and the two other modalities (without splint or with a balanced splint). The imbalanced occlusion created by the resin component corresponded to an average decrease of 9% in eccentric peak torque. The eccentric hamstring peak torques also showed a significant difference (p < 0.05) between measurements with splint and with resin (7% decrease when occlusion was imbalanced). In conclusion, among asymptomatic females, artificial imbalanced occlusion induces immediate and significant alteration of knee eccentric muscle performances. Therefore, occlusion examination should be undertaken on a regular and frequent basis for high-level athletes. Moreover, for athletes using mouthguards, muscular performance assessments should be planned with and without the dental protection. [less ▲]

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See detailThe Denticulate Mousterian as a supposedly distinct facies in Western Central Asia
Kolobova, K; Krivoshapkin, A; Pavlenok, K et al

in Archaeology, Ethnology & Anthropology of Eurasia (2012), 40(1),

Detailed reference viewed: 38 (1 ULg)