Assessment of the Contribution of Traffic Emissions to the Mobile Vehicle Measured PM2.5 Concentration by Means of WRF-CMAQ Simulations

INE/AUTC 12.0

Numerical investigations on the contribution of point source emissions to the PM2.5 concentrations in Fairbanks, Alaska

AbstractSimulations with and without consideration of emissions from point sources were performed with the Weather Research and Forecasting model with online chemistry (WRF/Chem) to examine the contribution of point source emissions to the PM2.5 concentrations at breathing level in Fairbanks, Alaska during winter. On days and at locations where PM2.5 concentrations exceed the National Ambient Air Quality Standard of 35μg m −3, emissions from point sources account for 4% of the 24h–average PM2.5 concentration on average. The locations of highest concentrations were the same in both simulations. Point source emissions induced only five additional exceedance days in the nonattainment area. The magnitude of the PM2.5 concentrations depended on meteorological conditions (temperature, wind speed, mixing height) and emissions. The radius of impact of point source emissions on the PM2.5 concentration at breathing level of about 10–12km downwind results as a combination of low emission heights, low wind speeds and the presence of inversions

Rapid load testing of piles in sand: Effect of loading rate and excess pore pressure

Civil Engineering and Geoscience

Literature review Quasi-static and Dynamic pile load tests: Primarily report on non-static pile load tests

Pile testing, which plays an importance role in the field of deep foundation design, is performed by static and non-static methods to provide information about the following issues: (Poulos, 1998) - The ultimate capacity of a single pile. - The load-displacement behavior of a pile. - The performance of a pile during the test conditions. - The integrity of a pile (pile integrity test). For the purposes of verification the design axial capacity and the static load – settlement behavior of piles, the static pile load test has long been considered as the most reliable method but because of its high cost and time consuming, non – static pile load tests are looked as efficient substitutions. The two non – static testing methods, i.e. dynamic and quasi – static pile load test are objects of this report. The non – static pile load tests are performed by means of exerting an impact force on the pile head while measuring and recording the responses of the pile, from which the test results are determined. Duration of the impact force (T), longitudinal wave velocity of tested pile (c) and pile length (L) are used as key factors to classify the testing methods

Pseudo-Lipschitz property of linear semi-infinite vector optimization problems

This paper is devoted to the study of the pseudo-Lipschitz property of Pareto solution map for the parametric linear semi-infinite vector optimization problem (LSVO). We establish new sufficient conditions for the pseudo-Lipschitz property of the Pareto solution map of (LSVO) under continuous perturbations of the right-hand side of the constraints and linear perturbations of the objective function. Examples are given to illustrate the results obtained.Linear semi-infinite vector optimization Pareto solution map Pseudo-Lipschitz mappings Linear perturbations Slater condition

Laboratory investigation of the loading rate effects in sand

In order to improve the interpretation of the quasi-static (e.g. Statnamic) pile load tests, a research project has been started to investigate effects of the loading rate on the bearing capacity of a pile in sand. A series of laboratory tests has been carried out. The testing program consists of a series of triaxial tests for sand and a series of load tests on a model pile embedded in sand in a large calibration chamber. The research pointed at answering two fundamental questions: - The effect of loading rate on the strength of sand and on the bearing resistance of a pile in sand; - The characteristics of excess pore pressure in sand and in the sand near the pile toe during a quasi-static load test. The results of the triaxial tests are: - In dry sand, a higher loading rate gives higher shear strength. In the range of applied loading rates, the angle of internal friction of the sand increases up to 2 degrees (strength increases 5-10%). - During high speed tests on dry sand an excess of pore air pressure is observed. So the dry sand is not in fully air drained condition during these tests. - The effects of loading rate in dry sand increase with the increase of relative density. - In saturated sand, the shear strength increases about 5% due to the rate effect. But, the true rate effect may be obscured by cavitation which occurs during the test. - Before cavitation occurs, the excess pore water pressure is independent of the loading rate. It depends on the relative density of the sand

Rapid pile load tests in the geotechnical centrifuge

Centrifiige experiments were carried out to gain insight into the factors that affect the mobilized resistance during rapid load testing on piles in sand. The influence of generated pore water pressure during rapid load tests is shidied, and its effect on the commonly used unloadmg point method to derive the staticpile capacity. This paper describes the testing program and the test set-up. Typical measurement results from 36 rapid- and 12 static load tests are presented. The effects of the loading rate and excess pore pressures on the pile resistance are shown. The tests confirm that a rapid load test can overestimate the static capacity due to pore water pressure, for piles in medium to fme sands. The results of the pore pressure measurements show a combination of positive and negative excess pore pressure in the zone around the pile base, which can be explained by compression, volumetric behavior durmg shearmg and pore fluid flow around the pile.Geoscience & EngineeringCivil Engineering and Geoscience