Capillary filling using Lattice Boltzmann Equations: the case of multi-phase flows

We present a systematic study of capillary filling for multi-phase flows by using mesoscopic lattice Boltzmann models describing a diffusive interface moving at a given contact angle with respect to the walls. We compare the numerical results at changing the density ratio between liquid and gas phases and the ratio between the typical size of the capillary and the interface width. It is shown that numerical results yield quantitative agreement with the Washburn law when both ratios are large, i.e. as the hydrodynamic limit of a infinitely thin interface is approached. We also show that in the initial stage of the filling process, transient behaviour induced by inertial effects and ``vena contracta'' mechanisms, may induce significant departure from the Washburn law. Both effects are under control in our lattice Boltzmann equation and in good agreement with the phenomenology of capillary filling

Dopamine treatment for severe ovarian hyperstimulation syndrome

Seven oliguric patients with severe ovarian hyperstimulation syndrome following gonadotrophin treatment for in-vitro fertilization or gamete intra-Fallopian transfer, were treated with low doses of dopamine by peripheral infusion. Five patients were pregnant. The rationale for this therapeutic approach was to increase renal blood flow and glomerular filtration. In addition to dopamine, fluid intake was restricted to 500 ml/day and a protein and salt-rich diet was provided in order to increase serum osmolarity. Within 24-48 h from the beginning of the dopamine treatment, the syndrome started to regress in all cases. No adverse maternal or fetal effects occurred. We conclude that dopamine therapy may constitute a major advance towards the management of severe ovarian hyperstimulation syndrom

Structure-type classification and flexibility-based detection of earthquake-induced damage in full-scale RC buildings

Detecting early damage in civil structures is highly desirable. In the area of vibration-based damage detection, modal flexibility (MF)-based methods have proven to be promising tools for promptly identifying changes in the global structural behavior. Many of these methods have been developed for specific types of structures, giving rise to different approaches and damage-sensitive features (DSFs). Although structural type classification is an important part of the damage detection process, this part of the process has received little attention in most literature and often relies on the use of a-priori engineering knowledge. Moreover, in general, experimental validations are only performed on small-scale laboratory structures with controlled artificial damage (e.g., imposed stiffness reductions). This paper proposes data-driven criteria for structure-type classification usable in the framework of MF-based damage identification methods to select the most appropriate algorithms and DSFs for detecting and localizing structural anomalies. This paper also tests the applicability of the proposed classification criteria and the damage identification methods on full-scale reinforced concrete (RC) structures that have experienced earthquake-induced damage. The considered structures are a seven-story RC wall building and a five-story RC frame building, which were both tested on the large-scale University of California, San Diego-Network for Earthquake Engineering Simulation (UCSD-NEES) shaking table

IVF treatment of moderate male factor infertility: a comparison of mini-Percoll, partial zona dissection and sub-zonal sperm insertion techniques

In this study we examined various techniques of in-vitro fertilization (IVF) for treating couples in whom the male had subnormal semen parameters. We compared two sperm preparation methods (mini-Percoll and conventional swim-up) for efficiency of recovery after preparation and for fertilization rates after IVF, and compared the suitability of partial zona dissection (PZD) and sub-zonal sperm insertion (SUZI) to patients with different types of male factor infertility. The mini-Percoll technique allowed the recovery of significantly more motile spermatozoa from the same semen sample compared to the swim-up method. More oocytes were fertilized after spermatozoa were prepared by the mini-Percoll technique. An increased number of spermatozoa recovered from an ejaculate led to an improvement in the quality of spermatozoa in the insemination droplet. Subsequently, when using the PZD technique, the fertilization rate increased when there was a higher number of spermatozoa in the patient's ejaculate. When comparing the two micromanipulation techniques, SUZI provided patients with oligoasthenzoo-spermia (i.e. < 10 × 106 spermatozoa/ml and 40% motility) with a higher chance of obtaining 2-pronculeate egg

An FDD-based modal parameter-less proportional flexibility-resembling matrix for response-only damage detection

Modal flexibility-based methods are effective tools for vibration-based structural damage detection, including in the output-only case. These methods are typically characterized by two stages: first, the modal parameters are identified, thus obtaining a certain number of modes; second, these modal parameters are used to assemble the modal flexibility matrix. This paper proposes a method for estimating a matrix that approximates a proportional flexibility matrix, termed proportional flexibility-resembling (PFR) matrix, and shows that this matrix can be used for damage detection and localization purposes. This matrix is obtained through signal processing operations to be executed after applying the first steps of the frequency-domain decomposition (FDD) technique-i.e., after the singular value decomposition of the spectral density matrix. The defining aspect of the PFR matrix is that, differently from the traditional formulation of modal flexibility and proportional flexibility matrices, it can be assembled without the need of an explicit identification of the modal parameters. In fact, the matrix is estimated by processing all first singular vectors and also all first singular values in a selected frequency range. In the proposed method, the typical two stage approach of traditional modal flexibility methods is avoided, and the intervention of an operator is limited to setting the values of a few parameters in the initial phase of the process. Numerical simulations and experimental data from a testbed structure were used to show the effectiveness of the proposed approach, and the analyses were performed by considering structures with different damage scenarios and damping properties

Application of modal flexibility-based deflections for damage diagnosis of a steel frame structure

Abstract In this paper a modal flexibility-based approach for damage diagnosis is presented and discussed. Modal flexibility matrices of structural systems can be derived from vibration tests and changes in these matrices can be associated to structural damage. One of the main challenges is to apply modal flexibility-based methods on real-life civil structures, to detect damage on structures using ambient vibration data. A recent method has been formulated for damage detection, localization, and quantification of building structures; it is based on the modal flexibility-based deflections of such structures under uniform loads. The method was originally formulated for frame buildings that can be modeled as plane shear-type structures. The objective of the paper is to test this methodology on generic buildings that, in principle, cannot be easily modeled as plane shear-type structures. The method was applied to the ambient vibration data of a steel frame structure that has a monitoring system with acceleration sensors. Various damage configurations were induced to the structure by removing diagonal braces on the external surface of the frame. The results showed that the method is able to identify the stories and the directions of the frame that have been affected by the damage

Evidence of thin-film precursors formation in hydrokinetic and atomistic simulations of nano-channel capillary filling

We present hydrokinetic Lattice Boltzmann and Molecular Dynamics simulations of capillary filling of high-wetting fluids in nano-channels, which provide clear evidence of the formation of thin precursor films, moving ahead of the main capillary front. The dynamics of the precursor films is found to obey the Lucas-Washburn law as the main capillary front, z2(t) proportional to t, although with a larger prefactor, which we find to take the same value for both geometries under inspection. Both hydrokinetic and Molecular Dynamics approaches indicate a precursor film thickness of the order of one tenth of the capillary diameter. The quantitative agreement between the hydrokinetic and atomistic methods indicates that the formation and propagation of thin precursors can be handled at a mesoscopic/hydrokinetic level, thereby opening the possibility of using hydrokinetic methods to space-time scales and complex geometries of direct experimental relevance.Comment: 11 pages, 6 figures. submitted to PR

Phenotype Screening of an Azole-bisindole Chemical Library Identifies URB1483 as a New Antileishmanial Agent Devoid of Toxicity on Human Cells

We report the evaluation of a small library of azole-bisindoles for their antileishmanial potential, in terms of efficacy on Leishmania infantum promastigotes and intracellular amastigotes. Nine compounds showed good activity on L. infantum MHOM/TN/80/IPT1 promastigotes with IC50 values ranging from 4 to 10 μM. These active compounds were also tested on human (THP-1, HEPG2, HaCaT, and human primary fibroblasts) and canine (DH82) cell lines. URB1483 was selected as the best compound, with no quantifiable cytotoxicity in mammalian cells, to test the efficacy on intracellular amastigotes. URB1483 significantly reduced the infection index of both human and canine macrophages with an effect comparable to the clinically used drug pentamidine. URB1483 emerges as a new anti-infective agent with remarkable antileishmanial activity and no cytotoxic effects on human and canine cells

Capillary filling with wall corrugations] Capillary filling in microchannels with wall corrugations: A comparative study of the Concus-Finn criterion by continuum, kinetic and atomistic approaches

We study the impact of wall corrugations in microchannels on the process of capillary filling by means of three broadly used methods - Computational Fluid Dynamics (CFD), Lattice-Boltzmann Equations (LBE) and Molecular Dynamics (MD). The numerical results of these approaches are compared and tested against the Concus-Finn (CF) criterion, which predicts pinning of the contact line at rectangular ridges perpendicular to flow for contact angles theta > 45. While for theta = 30, theta = 40 (no flow) and theta = 60 (flow) all methods are found to produce data consistent with the CF criterion, at theta = 50 the numerical experiments provide different results. Whilst pinning of the liquid front is observed both in the LB and CFD simulations, MD simulations show that molecular fluctuations allow front propagation even above the critical value predicted by the deterministic CF criterion, thereby introducing a sensitivity to the obstacle heigth.Comment: 25 pages, 8 figures, Langmuir in pres