Expertise Facility Types

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Our consultants regularly engage in research activities related to our normal client services. This archive includes the majority of the published technical papers, presentations, and other publications related to this research.

Voids Beneath Slabs-on-Ground: Using the impulse response test to verify adequate slab support

Introduction A concrete slab-on-ground is one of the most common of all floor types.  Slabs-on-ground are popular for many applications, especially in research facilities, where they usually provide the highest-quality vibration environment.  This is because they are stiff and uniformly supported, such that they do not exhibit the resonance characteristics of a suspended slab. As […]...
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Long-span truss structures for low-vibration environments

Historically, waffle slabs have been widely used in the process floor design in semiconductor production facilities.  In a less stringent vibration environment, concrete joist slab with stiffeners could be a suitable design option. In both of the two approaches, the effectiveness of vibration control in floor structures would be substantially reduced when the column span […]...
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Mode Selection for Footfall Analysis of Floors

Floor vibration due to footfall is of great importance in the design of buildings for vibration-sensitive research and production. The bulk of the predictive modeling methods for footfall involve the use of the “fundamental” resonance frequency which would be excited by the walker. In a complex structure, the analyst may be presented with a choice […]...
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Pellicle-Induced Distortions in Advanced Optical Reticles

William H. Semke, Lowell K. Siewert, Andrew R. Mikkelson, Eric A. Risius, Ning Tang, Roxann L. Engestad, Edward G. Lovell, Jun-Fei Zheng, Dao Giang, "Pellicle-Induced Distortions in Advanced Optical Reticles," Proceedings of SPIE 20th Annual BACUS Symposium on Photomask Technology, Vol. 4186, pp. 207-216, Monterey, CA, 2000....
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