Moisture Induced Damages to Building Foundations

The effect of moisture on foundation soils is a very important factor in the design of building foundations especially when the foundation soils are expansive in nature. The variations in subgrade moisture, with corresponding change in volume and strength characteristics of foundation soils may cause severe damage to the building. Two case histories are described where excess moisture in foundation soils caused damages to the building in distinctly different ways. In one case, moisture increase in the expansive foundation soils caused considerable swelling of the clays resulting in severe damage to the building. In the other case, excess moisture caused wash out of filter material causing considerable settlement of a sidewalk adjacent to a building. In both cases, excess moisture was related to a break in the underground water lines

An Experimental and Simulation Study of Early Flame Development in a Homogeneous-Charge Spark-Ignition Engine

An integrated experimental and Large-Eddy Simulation (LES) study is presented for homogeneous premixed combustion in a spark-ignition engine. The engine is a single-cylinder two-valve optical research engine with transparent liner and piston: the Transparent Combustion Chamber (TCC) engine. This is a relatively simple, open engine configuration that can be used for LES model development and validation by other research groups. Pressure-based combustion analysis, optical diagnostics and LES have been combined to generate new physical insight into the early stages of combustion. The emphasis has been on developing strategies for making quantitative comparisons between high-speed/high-resolution optical diagnostics and LES using common metrics for both the experiments and the simulations, and focusing on the important early flame development period. Results from two different LES turbulent combustion models are presented, using the same numerical methods and computational mesh. Both models yield Cycle-to-Cycle Variations (CCV) in combustion that are higher than what is observed in the experiments. The results reveal strengths and limitations of the experimental diagnostics and the LES models, and suggest directions for future diagnostic and simulation efforts. In particular, it has been observed that flame development between the times corresponding to the laminar-to-turbulent transition and 1% mass-burned fraction are especially important in establishing the subsequent combustion event for each cycle. This suggests a range of temporal and spatial scales over which future experimental and simulation efforts should focus

Optimizing the Stark-decelerator beamline for the trapping of cold molecules using evolutionary strategies

We demonstrate feedback control optimization for the Stark deceleration and trapping of neutral polar molecules using evolutionary strategies. In a Stark-decelerator beamline pulsed electric fields are used to decelerate OH radicals and subsequently store them in an electrostatic trap. The efficiency of the deceleration and trapping process is determined by the exact timings of the applied electric field pulses. Automated optimization of these timings yields an increase of 40 % of the number of trapped OH radicals.Comment: 7 pages, 4 figures (RevTeX) (v2) minor corrections (v3) no changes to manuscript, but fix author list in arXiv abstrac

TRENDS AND DEVELOPMENT IN CHIRONOMID PALAEOECOLOGY: SUMMARY FROM THE

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