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Considered types of casings
Published in Marek Pawelczyk, Stanislaw Wrona, Noise-Controlling Casings, 2023
Marek Pawelczyk, Stanislaw Wrona
The rigid casing discussed in this section is presented in Fig. 2.1, where dimensions, cross-sections and the method of mounting of casing walls are visualized. A photograph of the casing is given in Fig. 2.2. The casing has a heavy cubic frame made of 3mm thick welded steel profiles. The high rigidity of the frame results in its resonance frequencies to be far above frequencies of the noise considered. The bottom of the casing is vibrationally and acoustically insulated. All walls of the casing are made of single or double panels. Each panel is attached to the structure by 20 screws embedded in the frame, and clamped with an additional steel square frame. Fully-clamped boundary conditions can be then assumed for the panels, achieving satisfactory modelling accuracy. For double panels the distance between them is 50mm. The panel closer to the casing interior is called the incident panel, and the outer panel is referred to as the radiating panel.
Bridge design and rehabilitation using new Sandwich Plate System (SPS)
Published in Joan-Ramon Casas, Dan M. Frangopol, Jose Turmo, Bridge Safety, Maintenance, Management, Life-Cycle, Resilience and Sustainability, 2022
R.V. Gorga, N. Little, R. Maier, S. Gettler
Grande-Duchesse Charlotte bridge, also known as Pont Rouge (Figure 7) was built between 1962 and 1965 in the Kirchberg quarter, Luxemburg (Gesella et al. 2016, Stihl et al. 2016). It carries the Boulevard John F. Kennedy over the valley of the Alzette and is considered a bridge masterpiece of its era (currently a UNESCO World Heritage). The total length of the bridge is 355.0m, divided into three spans of 95.5m, 152.5m and 107.0m. The superstructure has a width of 25.0m, with a 14mm thick steel orthotropic deck forming the top flange of the two main box girders. The girders have a constant width of 6.0m, height between 2.3 and 6.4m and center-to-center spacing of 12.0m. Each girder is supported by a hollow steel square box section (2m sides) pinned at the base. The clear span between base support points is 234m and the maximum height above the valley is 75m.
Foundations
Published in Alan J. Lutenegger, Soils and Geotechnology in Construction, 2019
Grouted-shaft helical micropiles (GSHM) are a small-diameter version of the HCIPD pile previously described but have a diameter less than about 7 in. and consist of a lead helical section and extension sections with soil-displacement plates. The construction process is essentially the same as that described in Section 6.6.9.6 for HCIPD pile. In most cases, a central steel-square shaft of around 1.5 in. × 1.5 is used. The grout encapsulates the steel shaft so that the buckling strength is very high. The lead helical section is usually installed in good-bearing soil, and the hardened grout shaft transfers the load from the structure to the lead section once a structural bracket is attached to the structure. Several recent studies have described their successful use in a variety of soils (e.g., Downey and Brown 2003; Jennings and Bobbitt 2003; Seider et al. 2003; Lutenegger 2011; Lutenegger et al. 2013). Figure 6.77 shows the installation of GSHMs in progress to underpin a masonry structure.
Investigation of the gamma and neutron radiation properties of strontium bismuth borate glasses doped with neodymium ions using the Geant4 simulation toolkit and EpiXS software
Published in Radiation Effects and Defects in Solids, 2023
M.W. Aladailah, M.W. Marashdeh, H. Akhdar, O.L. Tashlykov, Al-Tamimi Walaa, Ayman Abu Ghazal
The rapid-quenching approach was used to modify B2O3Bi2O3SrO glasses with varying quantities of Nd2O3. Table 1 lists the glass sample batches. This glass system was created using the 99.9% pure oxides B2O3, Bi2O3, SrO, and Nd2O3. Powder oxides were weighed in the required amounts using a four-digit balance. To ensure that the oxide mixture was highly homogeneous, each sample was ground for two hours in a zirconia mortar and pestle. The combinations were fired in an alumina crucible at 450 oC for 1 hour to remove any leftover water on the particles. The mixtures were then melted at 1500 °C for 1 hour in a muffle furnace and immediately mixed to create clear, homogenous, bubble-free glass. The melted samples were placed into a steel square mold at a temperature of 400 °C. The samples were then annealed at 550 °C for 1 hour before being allowed to cool to room temperature within the furnace. The glasses were obtained in this manner and polished to a surface finish of approximately 1 × 1 × 0.2 cm3.
Construction, testing and performance analysis of a multi-stage traveling-wave thermo-acoustic generator
Published in International Journal of Green Energy, 2023
Miniyenkosi Ngcukayitobi, Lagouge Tartibu
The regenerators and heat exchangers are placed in a regenerator core (Figure 7) which must meet the following requirements: firstly, the effective conduction of the regenerator core has to be low since conductive heat losses from the hot to cold heat exchanger must be minimized. Secondly, the regenerator core must withstand temperatures up to 500 (Al-Kayiem 2017; RS components 2020). This part is made of a stainless-steel square pipe with galvanized flanges at the ends (Figure 7). The total length of the flanges and stainless-steel square pipe is 250 mm. All flanges are ASME grade 316 L and class 300. The regenerator core has a constant cross-sectional area throughout. The system was designed to handle a mean pressure of up to 10 bar. The regenerator core and flanges were machined according to the dimensions shown in Table 2. Flanges are welded on both sides to be joined to a steel pipe and a PVC pipe.
Hail ice impact simulation and damage response analysis in composite laminates
Published in Mechanics of Advanced Materials and Structures, 2023
Chao Zhang, Xin Fang, Jianchun Liu, Chunjian Mao
In the experiment, spherical hails of three diameters (D = 38.1, 50.8 and 61.0 mm) are implemented to impact the CFRP laminates of three stacking sequences at different velocities to determine the FTE. FTE is defined as the minimum kinetic energy of hail required to produce the initial delamination. The laminates are square with 304 × 304 mm side length of three thicknesses: 8 layers (H = 1.59 mm), 16 layers (H = 3.11 mm) and 24 layers (H = 4.66 mm). The stacking sequence of these three laminates are [0°/45°/90°/–45°]S, [0°/45°/90°/–45°]2S and [0°/45°/90°/–45°]3S, respectively. The laminates are fixed supported on all sides and the specimen is fastened to the bottom plate by pressure plate and bolts to achieve a stable state. The fixture is a 12.5 mm thick steel square frame with a 267 × 267 mm square opening. The hail is meshed by C3D8R elements and the element size of hail is 1 mm, 1.34 mm and 1.6 mm corresponding to hail diameters of 38.1, 50.8, and 61.0 mm. When the failure stress is reached, the failed hail elements are automatically converted into SPH particles to avoid large deformation.