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Technological and ergonomic aspects of selected muds application to the drilling of rescue holes in underground dog headings
Published in Vladimír Strakoš, Vladimír Kebo, Radim Farana, Lubomír Smutný, Mine Planning and Equipment Selection 1997, 2020
S. Stryczek, A. Gonet, A. Zięba, M. Wójcik
a pipe in a pipe type; 1 — shell, 2 — collar, 3 — water pipe, 4 — inner joint/coupling, 5 — collar, 6 — centralizer, 7 — rubber washer, 8 — air pipe; b) metal-ceramics type; 1 — shell, 2 — joint, 3 — pipe, 4 — cover, 5 — metal-ceramic filter, 6 — water inlet, 7 — rubber washer; c) simplified type; 1 — shell, 2 — joint, 3 — water inlet.
Experimental and theoretical analysis of air-inflated circular woven fabric deformation
Published in The Journal of The Textile Institute, 2019
Donya Najafzadeh, Saeed Shaikhzadeh Najar, Mohammad Reza Khedmati
The fabric sample was clamped by two plates with eight bolts. A rubber washer was used to seal the system. The inner diameter of the plates was 11.2 cm to provide the test area of about 98 cm2. In order to prevent air passage through the fabric, a silicon rubber sheet, with 0.45 mm thickness and Young modulus of 1.35 MPa was placed under the fabric sample. The air was supplied by an air compressor and an air regulator. A pressure gauge was used to read the air pressure inside the container. Each fabric was tested five times at air pressure values of 0.2, 0.4, 0.6, 0.8 and 1 bar.
Hands-on experiential learning of structural mechanics
Published in Australian Journal of Structural Engineering, 2019
The modification made to Prototype#2 to expedite construction was to essentially split the disks into two 3D-printed half-discs and merge the now exposed 45° and 60° radial half circle grooves over each 180° side of exposed face. All members ‘framing’ into the truss node concerned would be able to be clamped ‘in one hit’ in this Prototype#3 version via a rubber washer/metal washer combo that replaced the second half-disc of the original Prototype#2 design.
Investigation of torsional bracing of cold-formed steel roofing systems
Published in Journal of Structural Integrity and Maintenance, 2019
Shideh Shadravan, Mark Emde, Chris Ramseyer
In the construction industry, cold-formed steel construction has been proven to save money and materials due to the member’s high strength-to-weight ratio (Polyzois & Sudharmapal, 1988). These members are formed quickly and efficiently using continuous flow manufacturing roller mills, which can allow for easy changes in the design of a member with the adjustment of a single piece or setting. Metal building purlins or roof beams are increasingly provided in longer spans as the standard bay spacing increases. The original connection of roof panels to the beams was by using self-tapping screws directly connecting the purlin and panels. This is often referred to as a through-fastened system. The self-tapping screws include a rubber washer to create an exterior seal with the roof. But thermal expansion and contraction causes the roof panel to move relative to the screw. And weather tightness is only effective for fairly short roof spans where the thermal expansion and the elongated hole do not exceed the width of the washer. So as beam spans increased, and panel lengths increased, the amount of thermal movement increased and the screw holes became an increasing source of water leaks. Studies have shown that through-fastened roofing systems provide adequate lateral stability to the top flange of the purlins (Brooks and Murray, 1989; Anderson & Murray, 1990; Brooks & Murray, 1990; Katnam, Van Impe, Lagae, & De Beule, 2006; Lee & Murray, 2001; Murray & Elhouar, 1994; Neubert & Murray, 2000a, 2000b; Thottunkal, 2004; Wills & Wallace, 1990; Yu & Schafer, 2002, 2005, 2006, 2007; Zhao, 2014), but expansion and contraction allowed for leaks that shortened the life of the roof. Another disadvantage of the through-fasten roofing system is that insulation can only be installed between purlins. This creates a less energy efficient building due to thermal bridging and a more labor-intensive installation process (Yu & Schafer, 2005).