When urban modernisation entails service delivery co-production: a glance from Medellin

International audienceThrough the example of Ciudadela Nuevo Occidente, a large social housing district in Medellín, this article describes a process that primarily involves co-learning and micro-negotiations that help produce the cognitive alignment necessary to the management of services. The hypothesis put forward in this article is that the frictions caused by the residents' difficulties in adapting to the socioeconomic , cultural and cognitive frameworks of their new environment, imposed by urban modernisation running processes, engender forms of service co-production that ultimately strengthen the utility's capacity to extend and adapt its delivery model while enhancing the quality of services

Modeling and simulation in tribology across scales: An overview

This review summarizes recent advances in the area of tribology based on the outcome of a Lorentz Center workshop surveying various physical, chemical and mechanical phenomena across scales. Among the main themes discussed were those of rough surface representations, the breakdown of continuum theories at the nano- and micro-scales, as well as multiscale and multiphysics aspects for analytical and computational models relevant to applications spanning a variety of sectors, from automotive to biotribology and nanotechnology. Significant effort is still required to account for complementary nonlinear effects of plasticity, adhesion, friction, wear, lubrication and surface chemistry in tribological models. For each topic, we propose some research directions

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Nonequilibrium molecular dynamics simulations of stearic acid adsorbed on iron surfaces with nanoscale roughness

Nonequilibrium molecular dynamics (NEMD) simulations have been used to examine the structure and friction of stearic acid films adsorbed on iron surfaces with nanoscale roughness. The effect of pressure, stearic acid coverage, and level of surface roughness were investigated. The direct contact of asperities was prevented under all of the conditions simulated due to strong adsorption, which prevented squeeze-out. An increased coverage generally resulted in lower lateral (friction) forces due to reductions in both the friction coefficient and Derjaguin offset. Rougher surfaces led to more liquidlike, disordered films; however, the friction coefficient and Derjaguin offset were only slightly increased. This suggests that stearic acid films are almost as effective on contact surfaces with nanoscale roughness as those which are atomically-smooth

Atomistic and artificial intelligence simulations of grain boundaries and dislocations

Materials Science & EngineeringMechanical, Maritime and Materials Engineerin

LAMMPS_Builder

This software is suitable as a starting point for performing confined nonequilibrium molecular dynamics (NEMD) simulations of organic friction modifier (OFM) films adsorbed to iron surfaces, separated by a layer of n-alkane molecules: This software generates a LAMMPS datafile and basic input file containing: * Two a-Fe or a-Fe2O3 slabs with/without random nanoscale roughness * Two OFM monolayers above/below bottom/top slabs * A central region of n-alkanes https://doi.org/10.5281/zenodo.1043868This software is suitable as a starting point for performing confined nonequilibrium molecular dynamics (NEMD) simulations of organic friction modifier (OFM) films adsorbed to iron surfaces, separated by a layer of n-alkane molecules: This software generates a LAMMPS datafile and basic input file containing: * Two a-Fe or a-Fe2O3 slabs with/without random nanoscale roughness * Two OFM monolayers above/below bottom/top slabs * A central region of n-alkanes https://doi.org/10.5281/zenodo.104386

Predicting dislocation density in martensite ab-initio

The high dislocation density (ρd) in Fe-C and/or Fe-N martensite is known to be one of the main causes of its overall yield strength. Experiments indicate that the dislocation density and, therefore, the yield strength of martensite in low and medium C steels, follows a well defined behavior with respect to the background concentration of C (c0). In the present work, we introduce a model based on the finding that the dislocation density after γ→α' is sufficiently high to accommodate/trap most of the available interstitials (C or N) within Cottrell atmospheres. We show that the number of interstitials trapped in Cottrell atmospheres scales with the interaction energy between the stress field of the dislocations and the C/N misfit tensor. The new model, which contains no free fitting parameters, shows that the dislocation density scales as ρd∼c01/4, leading to an extremely good match with experiments across a wide range of C and N concentrations. Therefore, this model sheds light on the mechanistic origin of dislocation strengthening in Fe-C and Fe-N martensite

Effects of aberrations in vortex-beams generated with amplitude diffraction gratings

We present a mathematical model for the generation of vortex-beams by using a square profile amplitude fork diffraction grating with arbitrary topological charge. The mathematical framework of aberrations in the forked-shape diffraction grating is analysed, and the resulting diffracted pattern is simulated. Three cases of desired distortions (aberrations) in the diffraction grating are considered, obtaining phase modulation from the amplitude grating. Experimental optical vortices are generated by using a transmission spatial light modulator, which is used as a dynamic diffraction grating, allowing us to aberrate it. We show the effect of aberrations in the experimental diffracted vortex-beams and compare it with the numerical simulation. © 2016 SPIE