Long-range depletion forces induced by associating small molecules

This is the first report of experimental observations of depletion interactions in solutions of a (hydrogen-bonded) reversible supramolecular polymer. Depletion forces were measured directly by colloidal probe atomic force microscopy. The range of the depletion force is consistent with existing independent experimental data. The interaction can be tuned by adding monofunctional chain stoppers to the solution, a possibility which is unique to supramolecular polymers. The depletion force is shown to be strong enough to induce phase separation in a colloidal suspension.     

An Evolutionary Algorithm and discrete event simulation for optimizing inspection strategies for multi-stage processes

The problem of determining the optimal inspection strategy for a given multi-stage production process, i.e. the inspection strategy that results in the lowest total inspection cost, while still assuring a required output quality, is modelled as a joint optimization of inspection location, type and inspection limits. A fusion between a discrete event simulation to model the multi-stage process subject to inspection and to calculate the resulting inspection costs, and an Evolutionary Algorithm (EA) to optimize the inspection strategies, is suggested.     

The “Historical Materials BAG”: A New Facilitated Access to Synchrotron X-ray Diffraction Analyses for Cultural Heritage Materials at the European Synchrotron Radiation Facility

The European Synchrotron Radiation Facility (ESRF) has recently commissioned the new Extremely Brilliant Source (EBS). The gain in brightness as well as the continuous development of beamline instruments boosts the beamline performances, in particular in terms of accelerated data acquisition. This has motivated the development of new access modes as an alternative to standard proposals for access to beamtime, in particular via the “block allocation group” (BAG) mode. Here, we present the recently implemented “historical materials BAG”: a community proposal giving to 10 European institutes the opportunity for guaranteed beamtime at two X-ray powder diffraction (XRPD) beamlines—ID13, for 2D high lateral resolution XRPD mapping, and ID22 for high angular resolution XRPD bulk analyses—with a particular focus on applications to cultural heritage. The capabilities offered by these instruments, the specific hardware and software developments to facilitate and speed-up data acquisition and data processing are detailed, and the first results from this new access are illustrated with recent applications to pigments, paintings, ceramics and wood.     

Routing relatively few customers per route

This paper presents a modification of the well-known Solomon (1987) sequential insertion heuristic I1 for the Vehicle Routing Problem with Time Windows (VRPTW). VRPTW involves servicing customers within a pre-specified service time window by homogeneously capacitated vehicles from a single depot. By using two new measures for the additional time needed to insert a customer in the route, significantly better solutions are obtained for relatively short routes compared to the original Solomon (1987) sequential insertion heuristic I1. Because high-quality initial heuristics often allow local searches and metaheuristics to achieve better solutions more quickly, the new approach is likely to help generating better solutions to practical routing problems.     

Recent Updates on the Barrier Properties of Ethylene Vinyl Alcohol Copolymer (EVOH): A Review

The gas barrier properties of ethylene vinyl alcohol copolymer (EVOH) against oxygen, carbon dioxide and water vapor have been widely investigated in relation to different material characteristics, environmental conditions and new processing technologies. Recently, EVOH is gaining more attention as a barrier material against other gases and organic substances such as aromas, flavors, fuels, chemicals (e.g., BTEX), and as a functional barrier, e.g., to avoid mineral oil migration. This review contains an update on permeability data of EVOH emphasizing its potential as a barrier material for new and versatile applications in food and pharmaceutical packaging, agriculture, construction, automotive, etc.     

Self-assembled monolayers of octadecanoic acid on indium arsenide

Self-assembled monolayers (SAMs) of octadecanoic acid (ODA) on oxidized InAs were prepared and characterized, and their stability in ambient, solvents and against heating was investigated. Results confirm the formation of densely packed, well-ordered monolayers. Storage of ODA SAMs in ambient does not lead to any noticeable degradation for months. ODA can be rinsed off the surface by some organic solvents, but SAMs are stable in water. ODA SAMs are stable up to 120 °C in ambient, above which temperature ODA starts to desorb. Above 200 °C, oxidation of the InAs substrate occurs.     

Nickel(II) complexes with oxamides. The crystal structure of the nickel(II)-N-(hydroxyethyl)oxamide sodium salt

Summary The title compound crystallizes in the monoclinic space group C 2/c witha = 20.598 A.b = 4.208 A.c = 15.496 A. = 101.3 and Z = 4. The structure was solved by conventional techniques to an R = 0.051 using 1413 diffractometer data. The accurately square-planar Ni-atom is four-coordinated by deprotonated nitrogen atoms of two substituted oxamide ligands, [L = l-₂,N000ONH(CH₂)₂OH]. Two different nickel-nitrogen bonding distances were observed. indicating that Ni^II hinds more strongly to a primary than to a secondary nitrogen. The terminal alcohol group is part of the Na-coordination which can be described as a distorted prism. The preparation of the title compound and other homologous complexes is reported.Deceased November 1979.To whom correspondence should he addressed.     

Evolutionary Algorithms for the Vehicle Routing Problem with Time Windows

This paper surveys the research on evolutionary algorithms for the Vehicle Routing Problem with Time Windows (VRPTW). The VRPTW can be described as the problem of designing least cost routes from a single depot to a set of geographically scattered points. The routes must be designed in such a way that each point is visited only once by exactly one vehicle within a given time interval. All routes start and end at the depot, and the total demands of all points on one particular route must not exceed the capacity of the vehicle. The main types of evolutionary algorithms for the VRPTW are genetic algorithms and evolution strategies. In addition to describing the basic features of each method, experimental results for the benchmark test problems of Solomon (1987) and Gehring and Homberger (1999) are presented and analyzed.