Dynamics of fluid circulation in coupled free and heterogeneous porous domains

Fluid flow in coupled free and porous domain, particularly when the porous medium is heterogeneous, is encountered in many hydro-environmental conditions, e.g., leakage from underground pipe, combined groundwater lake-subsurface interactions. One of the most difficult problems in the study of coupled flow behaviour has been the development of a universally applicable modelling scheme for combining the flow regimes. This is because the free/porous interfacial properties (e.g., shear-stress; velocity slip) that govern the coupled flow behaviour are difficult to determine experimentally under hydro-environmental conditions. On the other hand, the implications of various forms of heterogeneity in the porous media properties can be very different on the fluid-flow behaviour. Difficulties may also arise in direct coupling of the model equations that govern the fluid flow in the individual regions (e.g., Navier-Stokes for free-flow region and the Darcy's equation for the porous flow region). Consequently, models of coupled free and porous flow for hydro-environmental conditions are not very well developed at the moment. While there are some indications that fluids in coupled free and porous domains may circulate (i.e., development of flow cells), there is a lack of appropriate 3D analysis on how heterogeneities in porous media may affect such flow patterns. In this paper, we aim to analyse how porous media heterogeneity affects the dynamics of flow circulation in the porous side of a coupled free and porous domain. For this purpose, we analyse flow patterns in several model domains made up of two porous layers with differing permeabilities. The governing model equations are discretised and solved using the standard finite volume method on a staggered cell-centred mesh. The temporal discretisation is done using the explicit method. An in-house graphical user interface (GUI) has been created specifically to aid in the visualisation of otherwise complex flow patterns. The GUI contains many post-processing options and provides a comprehensive tool for the analysis of hydrodynamics and contaminant motion (not discussed in this paper) in coupled free and porous flow domains. This GUI is described in this paper briefly. The effects of altering the aspect ratio (i.e., multi-scale) of the domain on the coupled flow pattern have also been discussed.     

L'évaluation des relations parents-enfants.

Parents have an influence on the evolution of their child and his/her successes in school, sports or music. Their support by example is critical. Some of their behaviours can also have a negative impact. Research aiming at better defining parents/child relations and their influence on the successes and the well-being of the child is needed. To this end, the use of a questionnaire is profitable. But there are few valid tools available in French. The existing tools do not focus on the evaluation of essential dimensions of child development. To palliate this deficiency, this article aims at validating the QéRPE (Questionnaire d'évaluation des relations parents/enfant), the French translation of the EMBU (Egna Minnen Betr?ffende Uppfostran, Perris et al., 1980). It underscores the level of support, overprotection and reject felt by the child by his parents. It is applied here in a relation parents/sport. The factor pattern (exploratory and confirmatory analysis) and the internal consistency of the QéRPE have been tested, and an external validation has been made. Results show that the psychometrics quality of the QéRPE is very acceptable. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How to measure human adaptation in extreme environments: the case of Antarctic wintering-over

BACKGROUND: Whether wintering-over causes cognitive and sensory impairment and associated adaptation problems is still a subject of debate. Conflicting results reported in the literature may be due to the difference in the experimental tasks. Moreover, interpersonal variability can hide the effects. HYPOTHESIS: Performance on cognitive and psychomotor tasks can be an indicator of adaptation problems. METHODS: Subjects were 10 scientists and 6 technicians (both clinically normal) who wintered-over for a year in the Antarctic. A subset of tasks of the AGARD battery of Standardized Tests for Research with Environmental Stressors (SB) was completed eight times during the isolation. To assess adaptation, the adaptability questionnaire (AQ) was completed by the physician before every performance test. RESULTS: SB showed a sensitive period of adaptation at mid-winter and at the end of the isolation, but the performance in the different tasks did not deteriorate exactly at the same time. No systematic relationship between AQ notations and SB performances was noted. However, three subjects showed significant positive correlations: r > 0.8, p < 0.05 (i.e., low adaptation = low performance). CONCLUSION: Some clinically normal individuals can experience adaptation problems, and SB tasks can be an indicator of these problems when comparisons are done at an individual level.     

Cage like ordered carboxylic acid functionalized mesoporous silica with enlarged pores for enzyme adsorption

Cubic FDU-12 type mesoporous silicas with enlarged pores and carboxylic acid (–COOH) functionality in the pore channels (denoted as LP-FTC-x) are synthesized using tetraethyl orthosilicate (TEOS) and carboxyethylsilanetriol sodium salt (CES) as silica sources, Pluronic F127 triblock copolymer as template, and trimethylbenzene (TMB) as pore expander, and utilized them as supports for enzyme immobilization. When the –COOH content is increased from 0 to 30%, the pore size of LP-FTC-x decreases from 23.6 to 11.1 nm, and its particle size decreases from around 2 μm to 600–800 nm. The material exhibits a high papain adsorption capacity (895 mg g^?1) with a low leaching rate at pH 8.2 due to the well-defined surface chemistry in the pore channel. The adsorption kinetics and isotherms follow the pseudo-second-order model and the Langmuir isotherm model, respectively. The excellent structural properties of LP-FTC-x are also advantageous for enhancement in stability of enzyme toward the temperature, solution pH, and incubation time variations.     

Preorder-based triangle: a modified version of bilattice-based triangle for belief revision in nonmonotonic reasoning

Bilattice-based triangle provides an elegant algebraic structure for reasoning with vague and uncertain information. But the truth and knowledge ordering of intervals in bilattice-based triangle cannot handle repetitive belief revisions which is an essential characteristic of nonmonotonic reasoning. Moreover, the ordering induced over the intervals by the bilattice-based triangle is not sometimes intuitive. In this work, we construct an alternative algebraic structure, namely preorder-based triangle and we formulate proper logical connectives for this. It is also demonstrated that Preorder-based triangle serves to be a better alternative to the bilattice-based triangle for reasoning in application areas, that involve nonmonotonic fuzzy reasoning with uncertain information.     

Experimental investigation of hysteretic dynamic effect in capillary pressure–saturation relationship for two‐phase flow in porous media

Well‐defined laboratory experiments have been carried out to investigate hysteretic dynamic effect in capillary pressure–saturation relationships for two‐phase flow in homogeneous and heterogeneous (layered) porous media. Conceptually, the dependence of the capillary pressure curves on the rate of change of saturation (dS_w/dt) is defined as the dynamic effect in capillary pressure relationship, which is indicated by a dynamic coefficient, τ (Pa s) and it determines the rate at which two‐phase flow equilibrium is reached, i.e., dS_w/dt = 0 where S_w and t are the water saturation and time, respectively. The dependences of τ on various fluid and porous materials properties have been studied in the context of drainage; but, there is limited study for imbibition and the hysteresis of τ?S_w relationships. As such, the emphasis in this article is on reporting τ?S_w curves for imbibition while also demonstrating the hysteresis in the τ?S_w relationships by comparing τ?S_w curves for drainage (previously reported) and imbibition (this study) in carefully designed laboratory experiments. Homogeneous sand samples composed of either fine (small particle size and lower permeability) or coarse (larger particle size and higher permeability) sand have been used for these experiments. Furthermore, a layered domain made of a find sand layer sandwiched between two coarse sand layers is used as a model of heterogeneous domain. The results of the study confirm that the τ?S_w relationships are hysteretic in nature and, as such, the speed to flow equilibrium should vary depending on whether drainage or imbibition takes place. At a particular water saturation, the magnitudes of the dynamic coefficient (τ) are found to be generally higher for imbibition, which imply that the speed to flow equilibrium at the same saturation will be slower for imbibition. © 2013 The Authors. AIChE Journal, published by Wiley on behalf of the AIChE. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. AIChE J, 59: 3958–3974, 2013     

Automated manufacturability analysis: A survey

In the market-place of the 21st century, there is no place for traditional over-the-wall communications between design and manufacturing. In order to design it right the very first time, designers must ensure that their products are both functional and easy to manufacture. Software tools have had some successes in reducing the barriers between design and manufacturing. Manufacturability analysis systems are emerging as one such tool — enabling identification of potential manufacturing problems during the design phase and providing suggestions to designers on how to eliminate them.In this paper, we provide a survey of current state-of-the-art automated manufacturability analysis. We present the historical context in which this area has emerged and outline characteristics to compare and classify various systems. We describe the two dominant approaches to automated manufacturability analysis and overview representative systems based on their application domain. We describe support tools that enhance the effectiveness of manufacturability analysis systems. Finally, we attempt to expose some of the existing research challenges and future directions.     

Highly conductive and electrochemically stable plasticized blend polymer electrolytes based on PVdF-HFP and triblock copolymer PPG-PEG-PPG diamine for Li-ion batteries

A new plasticized poly(vinylidene fluoride-co-hexafluoropropylene (PVdF-HFP)/PPG-PEG-PPG diamine/organosilane blend-based polymer electrolyte system has been synthesized and characterized. The structural and electrochemical properties of the electrolytes thus obtained were systematically investigated by a variety of techniques including differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile test, Fourier transform infrared spectroscopy (FTIR), ¹³C and ²⁹Si solid-state NMR, AC impedance, linear sweep voltammetry (LSV) and charge-discharge measurements. The FTIR and NMR results provided the information about the interaction among the constituents in the blend polymer membrane. The present blend polymer electrolyte exhibits several advantageous electrochemical properties such as ionic conductivity up to 1.3 × 10⁻² S cm⁻¹ at room temperature, high value of Li⁺ transference number (t₊ = 0.82), electrochemical stability up to 6.4 V vs. Li/Li⁺ with the platinum electrode, and stable charge-discharge cycles for lithium-ion batteries.     

A reversible approach to two’s complement addition using a novel reversible TCG gate and its 4 dot 2 electron QCA architecture

Microsystem Technologies - Classical computers are already facing threshold limitations with CMOS getting restricted to clocking speeds in GHz range and alarming heat dissipation issues. Both these...     

Microneedles from fish scale biopolymer

This article reports on microneedles produced from biopolymer films extracted from fish scales of tilapia (Oreochromiss sp.) using micromolding technique. Evaluation of the properties of polypeptide films prepared from the fish scales gave refractive index (1.34), protein concentration (78%), ash content (1.6%) at (22%) moisture content. The microneedles successfully inserted into artificial skin models and imaging using digital camera showed microneedles remained intact when inserted and when removed from the skin model. Microneedles also successfully inserted into porcine skin and were shown to dissolve gradually at 0 s, 60 s, 120 s, and 180 s after insertion. Microneedles containing methylene blue as model drug were also produced and successfully pierced porcine skin. 3D finite element (FEM) simulations were performed using the measured mechanical properties of the biopolymer films (Young's modulus 0.23 N/mm² and tensile strength 1.8105 N/mm²) to evaluate the stress distribution on various dimensions of the fish scale derived microneedles and hence, their ability to withstand force necessary to pierce the skin without fracture. Results from mechanical analysis using FEM showed that microneedles with tip radius between 10 and 100 μm could withstand up to 0.12 N of force per microneedle without fracture, which is indicated when the stress at the tip of the microneedle exceeds the ultimate stress of the material of fabrication. Using skin insertion tests and finite element simulations, this study provides evidence that microneedles fabricated from fish scale biopolymer can effectively pierce and degrade into skin and therefore are good candidate for transdermal applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40377.