Thermally Activated Dynamics of the Capillary Condensation

This paper is devoted to the thermally activated dynamics of the capillary condensation. We present a simple model which enables us to identify the critical nucleus involved in the transition mechanism. This simple model is then applied to calculate the nucleation barrier from which we can obtain informations on the nucleation time. We present a simple estimation of the nucleation barrier in slab geometry both in the two dimensional case and in the three dimensional case. We extend the model in the case of rough surfaces which is closer to the experimental case and allows comparison with experimental datas.Comment: 6 pages, 3 figures, Submitted to J. Phys. : Condens. Matter, Proceedings of the IV Liquid Matter Conference - Grenada(Spain) july 199

Where does a cohesive granular heap break?

In this paper, we consider the effect of cohesion on the stability of a granular heap. We first briefly review literature results on the cohesion force between two rough granular beads and specifically consider the dependence of the adhesion force on the normal load. We then compute the dependence of the maximum angle of stability of the heap as a function of the cohesion. We point out that the dependence of the cohesive forces on the external normal load between grains is a key point in determining the localization of the failure plane. While for a constant cohesive force, slip occurs deep inside the heap, surface failure is obtained for a linear dependence of the cohesion on the normal stress.Comment: 6 pages, 6 figures. Submitted to Phys. Rev.

A Semantic Web Annotation Tool for a Web-Based Audio Sequencer

Music and sound have a rich semantic structure which is so clear to the composer and the listener, but that remains mostly hidden to computing machinery. Nevertheless, in recent years, the introduction of software tools for music production have enabled new opportunities for migrating this knowledge from humans to machines. A new generation of these tools may exploit sound samples and semantic information coupling for the creation not only of a musical, but also of a "semantic" composition. In this paper we describe an ontology driven content annotation framework for a web-based audio editing tool. In a supervised approach, during the editing process, the graphical web interface allows the user to annotate any part of the composition with concepts from publicly available ontologies. As a test case, we developed a collaborative web-based audio sequencer that provides users with the functionality to remix the audio samples from the Freesound website and subsequently annotate them. The annotation tool can load any ontology and thus gives users the opportunity to augment the work with annotations on the structure of the composition, the musical materials, and the creator's reasoning and intentions. We believe this approach will provide several novel ways to make not only the final audio product, but also the creative process, first class citizens of the Semantic We

Slow Kinetics of Capillary Condensation in Confined Geometry: Experiment and Theory

When two solid surfaces are brought in contact, water vapor present in the ambient air may condense in the region of the contact to form a liquid bridge connecting the two surfaces : this is the so-called capillary condensation. This phenomenon has drastic consequences on the contact between solids, modifying the macroscopic adhesion and friction properties. In this paper, we present a survey of the work we have performed both experimentally and theoretically to understand the microscopic foundations of the kinetics of capillary condensation. From the theoretical point of view, we have computed the free energy barrier associated with the condensation of the liquid from the gas in a confined system. These calculations allow to understand the existence of very large hysteresis, which is often associated with capillary condensation. This results are compatible with experimental results obtained with a surface forces apparatus in a vapor atmosphere, showing a large hysteris of the surface energy of two parallel planes as a function of their distance. In the second part, we present some experiments on the influence of humidity on the avalanche angle of granular media. We show that the ageing in time of this avalanche angle can be explained by the slow kinetics of capillary condensation in a random confined geometry.Comment: Special Volume of Colloids and Surfaces A,Proceedings of Nanocapillarity: Wetting of Heterogeneous Surfaces and Porous Solids,June 25-27, 2001, TRI/Princeton International Workshop, Editor: Alexander V. Neimar

The persistence of non-identity : spiritual experience in Adorno

Chez Adorno, l’expérience spirituelle devient un concept critique grâce à son caractère négatif; ce dernier n’est plus compris comme une voie par laquelle l’expérience immédiate est possible, mais plutôt en tant qu’expression d’une carence objective, bloquant la possibilité de fonder l’expérience sur l’immédiat. Le séparation entre sujet et objet devient l’expression épistémologique de cette carence, le processus de ‘désenchantement du monde’ son expression sociale. En reconstruisant la conception d’expérience spirituelle, il devient possible montrer dans quelle mesure cette carence sociale peut s’exprimer directement, tout dans un contexte épistémologique qui bloque la possibilité de communication directe; du coup, c’est seulement en répondant à ce problème que l’expérience gagne son caractère critique. Notre reconstruction se sert du concept de ‘donné’ (ou, l’objet de l’expérience immédiate) comme fil conducteur. Comme le concept de donné devient problématique dans le cas de l’idéalisme subjectif, nous partirons de l’échec que subit l’idéalisme dans son inclusion du donné dans son schéma transcendantal. Après nous établirons les aspects positifs de cette conception de l’expérience, qui deviennent intelligibles lors de sa critique du positivisme et la phénoménologie. Ces deux disciplines recouvrent le problème du désenchantement en fondant la possibilité de l’expérience sur une conception particulière du donné; c’est donc dans l’impossibilité d’une réduction de l’expérience au donné qu’il est possible de cerner comment l’expérience non-réduite pourrait se présenter. Dans la section finale, le concept d’expérience spirituelle est présenté dans sa positivité, en tant que réponse aux échecs du positivisme et la phénoménologie: autrement dit, le concept peut proprement exprimer l’expérience dans la mesure qu’il comprend comment l’expérience peut être faussée. En tant que réponse aux échecs des conceptions réducteurs de l’expérience, la qualité du concept d’Adorno est démontrée à travers sa capacité d’établir des connections entre la carence épistémique de ces conceptions réducteurs et les processus sociaux constituant le phénomène de désenchantement du monde.Adorno’s conception of spiritual experience gains its critical import from its predominantly negative character: experience is no longer understood as a vehicle for what is communicated to us directly, but instead as the expression of an objective lack that blocks the possibility of direct communication altogether. This lack is expressed epistemically by the subject-object split in Idealism, and socially by the process of “disenchantment” that is intrinsic to modernity. The aim of reconstructing Adorno’s conception of spiritual experience is to show how this social lack can be adequately communicated within an epistemic context that blocks the possibility of direct communication; conversely, it is only once this problem is surmounted that the critical import of spiritual experience can be established. We will reconstruct Adorno’s conception of spiritual experience on the basis of its relation to what is given, or what we assume is communicated directly to us in experience. As the given gains its problematic character in relation to idealistic accounts of experience, we will depart with the failure of subjective idealism to properly account for the given object in experience. Following this, we will show how the positive aspects of spiritual experience are established through the sustained critique of reified accounts of experience such as positivism and phenomenology. As both accounts aim to smooth-over the subject-object split by grounding experience in a particular form of givenness, we will show how their respective failures in reducing experience to givenness express the possibility of an un-reduced account of the former. The final section of the work will attempt to establish Adorno’s conception of spiritual experience as a positive response to these failures: in other words, it attempts to get something right about experience on the basis of how the latter is wrongly construed. More precisely, the concept’s adequacy as a response is demonstrated through its ability to make connections between the epistemic insufficiencies of reductionistic accounts of experience and the social processes which underpin the phenomenon of disenchantment

La vita. (Torino, 20 dicembre 1833 - Savona, 31 dicembre 1914)

ITALIANO: Il testo ripercorre la vita di Vittorio Poggi, sulla base del suo archivio, in particolare del carteggio. Dopo un breve cenno alla famiglia si esaminano i suoi studi giovanili, l’inizio della professione forense e l’ambiente in cui maturano i suoi ideali; nel 1859, con la seconda Guerra di Indipendenza, l’entusiasmo patriottico lo spinge ad arruolarsi volontario e, successivamente, alla decisione di rimanere nell’esercito. La carriera militare lo porterà nei luoghi, soprattutto in Toscana, dove approfondisce lo studio dei reperti e della lingua etrusca; è in contatto con i maggiori studiosi tedeschi e italiani, fino a essere considerato un’indiscussa autorità in materia. Al termine della carriera, ritornato in Liguria, ricopre numerose cariche in ambito culturale a Genova e a Savona, intensificando l’attività di studio e di edizione di testi. / ENGLISH: The text reviews the life of Vittorio Poggi, based on his archives, in particular his correspondence. After brief reference to his family, it describes his early studies, the beginning of his legal profession and the setting within which his ideals take shape; in 1859, with the Second War of Independence, his patriotic zeal encourages him to sign up for military service as a volunteer and, subsequently, to remain in the army. His military career leads him in locations, especially in Tuscany, where he deepens further his study of Etruscan remains and language; he builds contacts with the foremost German and Italian scholars, so as to become an undisputed expert in the field. At career end, he returns to Liguria, where he holds numerous cultural appointments in Genoa and Savona, further concentrating on his studies and editing of texts

Critical Differences between Key Employee Retention Plans and Key Employee Incentive Plans

(Excerpt) Section 503(c) of the United States Bankruptcy Code (the “Bankruptcy Code”) imposes strict limitations on companies in chapter 11 who want to make bonus payments to retain employees. In particular, section 503(c) limits a chapter 11 debtor’s ability to favor employees over the interests of the estate to ensure that any bonus payment is designed for the overall benefit of the bankrupt estate. This memo details the differences between bonus payments under sections 503(c)(1) and 503(c)(3) and explains how a chapter 11 debtor should design bonus payments to employees to ensure those payments pass scrutiny under these provisions

Wall slip of complex fluids: interfacial friction or slip length?

Using a dynamic Surface Force Apparatus, we demonstrate that the notion of slip length used to describe the boundary flow of simple liquids, is not appropriate for viscoelastic liquids. Rather, the appropriate description lies in the original Navier's partial slip boundary condition, formulated in terms of an interfacial friction coefficient. We establish an exact analytical expression to extract the interfacial friction coefficient from oscillatory drainage forces between a sphere and a plane, suitable for dynamic SFA or Atomic Force Microscopy non-contact measurements. We use this model to investigate the boundary friction of viscoelastic polymer solutions over 5 decades of film thicknesses and one decade in frequency. The proper use of the original Navier's condition describes accurately the complex hydrodynamic force up to scales of tens of micrometers, with a simple "Newtonian-like" friction coefficient, not frequency dependent, and reflecting closely the dynamics of an interfacial depletion layer at the solution/solid interface.Comment: 7 pages, 5 figure