Natural cement and monumental restoration

Natural cement, called "Roman” cement, was invented at the end of the 19th century and played an important role in the development of civil engineering works until the 1860s. More surprisingly, it was also used to restore historic buildings, such as gothic cathedrals. This paper deals with the mineralogy and the durability of natural cement in the particular case of the Bourges Cathedral in France. This study illustrates the interest of this material particularly adapted in stone repair or substitution. Contrary to traditional mortars, the present samples are made of neat cement paste, revealed by the absence of mineral additions as quartz or carbonate sand. Several combined techniques (SEM-EDS, TGA, XRD) were carried out to determine the composition of the hydraulic binder rich in calcium aluminate hydrates. The raw marl at the origin of the cement production contains oxidized pyrites which consist in a potential source of sulphate pollution of the surrounding limestone. The exposition of the cement in urban environment leads to some weathering features as atmospheric sulfation. Finally a petrophysical approach, based on water porosity, capillary sorption and compressive strength, has been performed to demonstrate the durability and the compatibility of natural cement applied as an historical building restoration morta

Chern-Simons Theory on S^1-Bundles: Abelianisation and q-deformed Yang-Mills Theory

We study Chern-Simons theory on 3-manifolds $M$ that are circle-bundles over 2-dimensional surfaces $\Sigma$ and show that the method of Abelianisation, previously employed for trivial bundles $\Sigma \times S^1$, can be adapted to this case. This reduces the non-Abelian theory on $M$ to a 2-dimensional Abelian theory on $\Sigma$ which we identify with q-deformed Yang-Mills theory, as anticipated by Vafa et al. We compare and contrast our results with those obtained by Beasley and Witten using the method of non-Abelian localisation, and determine the surgery and framing presecription implicit in this path integral evaluation. We also comment on the extension of these methods to BF theory and other generalisations.Comment: 37 pages; v2: references adde

Influence of Music on Perceived Emotions in Film

Film music plays a core role in film production and reception as it not only contributes to the film aesthetics and creativity, but it also affects viewers' experience and enjoyment. Film music composers often aim to serve the film narrative, immerse viewers into the setting and story, convey clues, and importantly, act on their emotions. Yet, how film music influences viewers is still misunderstood. We conducted a perceptual study to analyse the impact of music on the perception of emotions in film. We developed an online interface for time-based emotion annotation of audio/video media clips based on the Valence/Arousal (VA) two-dimensional model. Participants reported their perceived emotions over time in the VA space for three media conditions: film scene presented without sound (video only), film music presented without video (audio only), and film scene with accompanying music and sound effects (both video and audio modalities). 16 film clips were selected covering four clips for each of four genres (action & drama, romance, comedy, and horror). 38 participants completed the study (12 females and 26 males from many countries, average age: 28.9). Density scatter plots are used to visualise the spread of emotion ratings in the VA space and differences across media conditions and film clips. Results from linear mixed effect models show significant effects of the audiovisual media condition and film genre on VA ratings, in line with previous results by Parke et al. [1]. Perceived VA ratings across media conditions follow an almost linear relationship with an increase in strength in the following order: film alone, film with music/sound, music alone. We illustrate this effect by plotting the VA rating centre of mass across conditions. VA ratings for the film-alone condition are closer to the origin of the space compared to the two other media conditions, indicating that the inclusion of music yields stronger emotions (higher VA ratings). Certain individual factors (musical ability, familiarity, preference) also seem to impact the perception of arousal and valence while viewing films. Our online emotion annotation interface was on overall well received and suggestions to improve the display of reference emotion tags are discussed

Développement de la tomographie intra-vitale au K-edge avec la caméra à pixels hybrides XPAD3

The hybrid pixel camera XPAD3 integrated in the micro-CT PIXSCAN IIis a new devicedeveloped by the imXgam team at CPPM for which photon counting replaces charge integrationused in standard X-ray CT. This novel approach involves advantages, in particularthe absence of dark noise and the ability to set an energy threshold on each pixel of thedetected photons. This features has been exploited during this thesis work for standardsmall animal preclinical imaging and permitted to establish the faisability of ex vivo, andthen in vivo labelling of marcrophages.On another hand, the ability of this camera is of uppermost importance for the developmentof K-edge imaging approaches, which exploit spectral information on the countedphotons. K-edge imaging permits to identify contrast agent compartiments with regardsto bones in classical radiography. K-edge imaging is obtained by selecting, for each pixelcalibration, those pixel that are set at one of the three different thresholds around theK-shell’s binding energy of the selected contrast agents and then, to proceed with a subtractionanalysis to the images obtained above and below the K-edge energy.We develop a new way of calibrating the XPAD3 detector that permits to provide theproof of concept of a patent owned by the imXgam team, and to obtain the first results onliving mice by dividing the acquisition time by three with a compromise on the resolution.This novel approach can be implemented in "two colours" in order to separate clearly twodifferent contrast agents. This brings a new way to visualize biological information and toprovide possible future approaches for the study of the inter-dependance of vascularisationand inflammation during the tumor development.La caméra à pixels hybrides XPAD3 intégrée dans le micro-tomodensitomètre PIXSCANII est un nouveau dispositif développé par l’équipe imXgam au CPPM dans lequelle comptage de photons remplace l’intégration de charges utilisée dans les systèmes deradiographie standard. La caméra XPAD3 apporte des avantages, en particulier l’absencede bruit de courant noir et la possibilité d’imposer un seuil de discrimination sur chaquepixel. Ces particularités ont pu être exploitées au cours de ce travail de thèse en imageriepréclinique classique sur petit animal et ont permis de faire la preuve de faisabilité d’unmarquage ex-vivo puis intra-vital des macrophages.D’autre part les capacités de cette caméra sont intéressantes pour le développement d’unenouvelle méthode d’imagerie spectrale dite au K-edge. L’imagerie au K-edge permet dedifférencier des compartiments contenant un agent de contraste par rapport à l’os dans desradiographies classiques. Elle est obtenue via l’étalonnage de trois différents seuils autourde l’énergie de liaison de la couche K de l’agent de contraste considéré. Le développementd’un nouvel d’étalonnage avec l’utilisation de pixels composites a permis d’établir la preuvede concept d’un brevet déposé par l’équipe imXgam et d’obtenir les premiers résultatssur souris vivantes en divisant le temps d’acquisition par trois avec un compromis sur larésolution spatiale.Cette nouvelle approche peut être implémentée en « deux couleurs » pour séparer deuxdifférents types d’agents de contraste. Ceci offre une nouvelle manière de visualiser desinformations biologiques pertinentes dans un contexte applicatif visant à étudier de manièredynamique (longitudinale) l’interdépendance de la vascularisation et de la réponseimmunitaire au cours du développement tumoral

Very Massive Star Models: I. Impact of Rotation and Metallicity and Comparisons with Observations

In addition to being spectacular objects, Very Massive Stars (VMS) are suspected to have a tremendous impact on their environment and on the whole cosmic evolution. The nucleosynthesis both during their advanced stages and their final explosion may contribute greatly to the overall enrichment of the Universe. Their resulting supernovae are candidates for the most superluminous events and their extreme conditions also lead to very important radiative and mechanical feedback effects, from local to cosmic scale. We explore the impact of rotation and metallicity on the evolution of very massive stars across cosmic times. With the recent implementation of an equation of state in the GENEC stellar evolution code, appropriate for describing the conditions in the central regions of very massive stars in the advanced phases, we present new results on VMS evolution from Population III to solar metallicity. Low metallicity VMS models are highly sensitive to rotation, while the evolution of higher metallicity models is dominated by mass loss effects. The mass loss affects strongly their surface velocity evolution, breaking quickly at high metallicity while reaching the critical velocity for low metallicity models. The comparison to observed VMS in the LMC shows that the mass loss prescriptions used for these models are compatible with observed mass loss rates. In our framework for modelling rotation, our models of VMS need a high initial velocity to reproduce the observed surface velocities. The surface enrichment of these VMS is difficult to explain with only one initial composition, and could suggest multiple populations in the R136 cluster. At a metallicity typical of R136, only our non- or slowly rotating VMS models may produce Pair Instability supernovae. The most massive black holes that can be formed are less massive than about 60 M$_\odot$.Comment: 13 pages, 11 figure

Plastic flow and structural heterogeneities in silicate glasses - A high throughput investigation

Please click Additional Files below to see the full abstract

Random perfect lattices and the sphere packing problem

Motivated by the search for best lattice sphere packings in Euclidean spaces of large dimensions we study randomly generated perfect lattices in moderately large dimensions (up to d=19 included). Perfect lattices are relevant in the solution of the problem of lattice sphere packing, because the best lattice packing is a perfect lattice and because they can be generated easily by an algorithm. Their number however grows super-exponentially with the dimension so to get an idea of their properties we propose to study a randomized version of the algorithm and to define a random ensemble with an effective temperature in a way reminiscent of a Monte-Carlo simulation. We therefore study the distribution of packing fractions and kissing numbers of these ensembles and show how as the temperature is decreased the best know packers are easily recovered. We find that, even at infinite temperature, the typical perfect lattices are considerably denser than known families (like A_d and D_d) and we propose two hypotheses between which we cannot distinguish in this paper: one in which they improve Minkowsky's bound phi\sim 2^{-(0.84+-0.06) d}, and a competitor, in which their packing fraction decreases super-exponentially, namely phi\sim d^{-a d} but with a very small coefficient a=0.06+-0.04. We also find properties of the random walk which are suggestive of a glassy system already for moderately small dimensions. We also analyze local structure of network of perfect lattices conjecturing that this is a scale-free network in all dimensions with constant scaling exponent 2.6+-0.1.Comment: 19 pages, 22 figure

Definition of an indicator assessing the impact of a dam on the downstream river landscape

The increasing number of water withdrawals in Alpine regions represents a significant threat to aquatic ecosystems and river landscape (riverscape). To assess their sustainability, the impacts on river ecological status and landscape features need to be quantified with appropriate indicators. However, assessment of landscape attributes is a complex challenge, due to the lack of standardized methods. Moreover, few metrics quantifying the impacts of water withdrawal on downstream riverscape perception are available in the scientific literature. In this paper, a new indicator, named Landscape Protection Level (LPL), aimed at assessing the effects of water withdrawals on the river landscape, is presented. The indicator has been developed in Aosta Valley (NW Italian Alps), where the river network is heavily exploited by hundreds of withdrawals for hydropower production and irrigation, and it has been included in a multi-criteria analysis (MCA) procedure to assess the sustainability of water withdrawal licenses in relation to different flow release scenarios. The LPL indicator is based on three parameters, Constraint Factor, Release Factor, and Visual Elements Factor, quantifying the presence of landscape protection constraints, the ratio of flow released downstream of the dam to the available river discharge, and the impact on the visual perception of the bypassed stretch, respectively. Its application in four real case studies of existing hydropower plants is presented and discussed in the paper, demonstrating the indicator applicability to assess both specific release values and flow release scenarios varying over the year. Results are analyzed by highlighting the main strengths and weaknesses of the indicator and proposing some suggestions for future improvements. In particular, the reactiveness of the indicator, the representativeness of the stakeholders’ interests, the transparency of the indicator calculation procedure, and the time required for data collection and processing are discussed. Finally, future activities aimed at further improving the indicator applicability and transferability to different river contexts are proposed

A Connection between Star Formation in Nuclear Rings and their Host Galaxies

We present results from a photometric H-alpha survey of 22 nuclear rings, aiming to provide insight into their star formation properties, including age distribution, dynamical timescales, star formation rates, and galactic bar influence. We find a clear relationship between the position angles and ellipticities of the rings and those of their host galaxies, which indicates the rings are in the same plane as the disk and circular. We use population synthesis models to estimate ages of each H-alpha emitting HII region, which range from 1 Myr to 10 Myrs throughout the rings. We find that approximately half of the rings contain azimuthal age gradients that encompass at least 25% of the ring, although there is no apparent relationship between the presence or absence of age gradients and the morphology of the rings or their host galaxies. NGC1343, NGC1530, and NGC4321 show clear bipolar age gradients, where the youngest HII regions are located near the two contact points of the bar and ring. We speculate in these cases that the gradients are related to an increased mass inflow rate and/or an overall higher gas density in the ring, which would allow for massive star formation to occur on short timescales, after which the galactic rotation would transport the HII regions around the ring as they age. Two-thirds of the barred galaxies show correlation between the locations of the youngest HII region(s) in the ring and the location of the contact points, which is consistent with predictions from numerical modeling.Comment: 23 pages, 10 figures (7 color), 23 tables, accepted for publication in ApJS (Feb 08); NASA-GSFC, IAC, University of Maryland, STSc

The structure of invariant tori in a 3D galactic potential

We study in detail the structure of phase space in the neighborhood of stable periodic orbits in a rotating 3D potential of galactic type. We have used the color and rotation method to investigate the properties of the invariant tori in the 4D spaces of section. We compare our results with those of previous works and we describe the morphology of the rotational, as well as of the tube tori in the 4D space. We find sticky chaotic orbits in the immediate neighborhood of sets of invariant tori surrounding 3D stable periodic orbits. Particularly useful for galactic dynamics is the behavior of chaotic orbits trapped for long time between 4D invariant tori. We find that they support during this time the same structure as the quasi-periodic orbits around the stable periodic orbits, contributing however to a local increase of the dispersion of velocities. Finally we find that the tube tori do not appear in the 3D projections of the spaces of section in the axisymmetric Hamiltonian we examined.Comment: 26 pages, 34 figures, accepted for publication in the International Journal of Bifurcation and Chao