Influence of geosynthetic reinforcement on the load-settlement characteristics of two-layer subgrade

The possibility of realistic prediction of two-layer subgrade load-settlement characteristics is discussed. The case of improvement of the soft subgrade properties using the geosynthetic reinforcement placed at the boundary between two different subgrade layers is analysed. In the first part of the paper, a short review of the main conclusions from experimental results dealing with the influence of geosynthetic reinforcement on the load-settlement characteristics of subgrade is presented. Then, the results of using the selected analytical membrane-action model to describe the reinforcement action in soil are discussed. The model is verified on the basis of data obtained from previously published laboratory tests. Particular attention is devoted to influencing some basic initial parameters on the accuracy of obtained results. Important problems which need intensive investigations are identified.     

Transport of reactants during scale formation on copper in SO2+O2 atmosphere at 973 and 1073 K

The reaction between copper and a mixture of SO₂+O₂ was studied at 973 and 1073 K. The experimental methods included optical microscopy, X-ray diffraction, scanning electron microscopy (SEM), energy-dispersive X-ray analysis, and radiotracer. It is concluded that the inward transport of oxidants through the scale as well as oxygen and sulfur dioxide liberation in the reactions taking place at phase boundaries suggest that secondary processes occur inside the oxide-sulphate layer. Therefore, Cu₂O and CuOCuSO₄ appear inside this layer. In the metal-consumption zone, a Cu₂O layer forms, which contains small amounts of a sulfide phase near the metal-scale interface.     

Preparation of lead (Pb) X-ray fluorescence reference materials for the EPA Pb monitoring program and the IMPROVE network using an aerosol deposition method

X-ray fluorescence (XRF) is a commonly used analytical method to quantify lead (Pb), a toxic element, in atmospheric aerosol. The commercially available reference materials used for calibrating XRF do not mimic the concentrations and filter materials of particulate matter (PM) monitoring networks. In this study, we described an aerosol deposition method to generate Pb reference materials (RMs) over a range of concentrations to serve several purposes for the US Environmental Protection Agency (EPA) and Interagency Monitoring of PROtected Visual Environments (IMPROVE) monitoring networks including laboratory auditing, federal equivalency method evaluation, and calibration and quality control of XRF instruments. The RMs were generated using a laboratory-built aerosol chamber equipped with a federal reference sampler at concentration levels ranging from 0.0125 to 0.70 μg/m³. XRF analysis at UC Davis was demonstrated to be equivalent to a US and EU reference method, inductively coupled plasma—mass spectrometry (ICP-MS), for measuring Pb on RMs following a methodology described in the United States and international standards. The Pb concentrations on subsets of the RMs were verified by three other XRF laboratories with different analyzers and/or quantification methods and were shown to be equivalent to the UC Davis XRF analysis. The generated RMs were demonstrated to have short and long-term stability, satisfying an additional requirement of reference materials.

Copyright © 2016 American Association for Aerosol Research     

Cyclization in chain-crosslinking copolymerization

Summary Styrene and ethylene dimethacrylate were polymerized in benzene solutions to high conversions. Gels were prepared from critical concentrations of the divinylidene monomer and the fractions of the divinylidene units engaged in intermolecular crosslinks were estimated. The fractions were found to be very small, viz. 5, 10 and 18 % at the total monomer concentrations 1, 2 and 3 mol/dm³, respectively. Behaviour of pregel polymers suggests that cyclization of primary chains and multiple crosslinking are responsible for the low efficiency of the crosslinking agent.Presented at the 7th IUPAC Discussion Conference Polymer Networks, Karlovy Vary, CSSR, September 15–19, 1980     

The influence of post-mortem ageing and roasting on the microstructure, texture and collagen solubility of bovine semitendinosus muscle

Bovine semitendinosus (ST) muscles aged for 5 and 12 days at 4?°C were roasted at 170?°C to internal temperatures of 50, 60, 70, 80 and 90?°C. Microstructural changes in meat were evaluated using a scanning electron microscope (SEM). Texture profile analysis (TPA) and measurements of the shear force values of samples were conducted using a texture analyser. The cooking losses and quantity of total and soluble collagen were also estimated. The structure of intramuscular connective tissue and myofibrillar structure of meat after 5 days of ageing was very regular. In 12-day-aged samples fibrous and myofibrillar structures were less distinct, damages of endomysium tubes appeared and fibres of perimysium were swelled. Ageing of ST muscle for 12 days caused a two-fold increase in the quantity of soluble collagen and a two-fold decrease in the value of TPA parameters-hardness and chewiness, as compared to 5-day-aged samples. The decrease in fibre diameter and sarcomere length during roasting started at 60?°C in 5-day-aged meat and at 50?°C in 12-day-aged samples. The shear force values measured after roasting were lower for 12-day-aged meat than for 5-day-aged samples. The quantity of soluble collagen in roasted meat increased at an internal temperature of 80?°C. At a higher temperature of meat this variable depended on the degree of meat ageing. The cooking losses during roasting of meat were about 3% lower for 12-day-aged than for 5-day-aged samples. In the examined range of internal temperature of meat the cooking losses and the sarcomere length were negatively correlated.     

Formal Mathematics for Mathematicians

The collection of works for this special issue was inspired by the presentations given at the 2011 AMS Special Session on Formal Mathematics for Mathematicians: Developing Large Repositories of Advanced Mathematics. The issue features a collection of articles by practitioners of formalizing proofs who share a deep interest in making computerized mathematics widely available.     

Adaptive rank weighted switching filter for impulsive noise removal in color images

Journal of Real-Time Image Processing - In this paper, a novel approach to the problem of impulsive noise removal in color digital images is presented. The described switching filter is based on...