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Microwave-Assisted Casting
Published in Amit Bansal, Hitesh Vasudev, Advances in Microwave Processing for Engineering Materials, 2023
Gaurav Prashar, Hitesh Vasudev, Amit Bansal
In the area of metal casting by using ME, a US patent was filed in 2006 claiming the technique and apparatus for melting metallic metals [21]. Researchers used ceramic crucible for metal melting. The crucible was enclosed in a ceramic casket for proper insulation. An oxygen-free environment was used for metal heating and fully molten metal was poured into a mold placed outside or in a mold located just underneath the crucible. In another experimental setup, a technique of modeling and simulation was put into use for industrial microwaves to melt metals, and thereafter, the temperature profile outcomes were validated [22]. Wiedenmann et al. [23], in another effort, used a mode stirrer for even distribution of ME in the cavity of the applicator. The computer aided design (CAD) model was developed first for experimental setup, and then both experimental and simulated outcomes for the profiles of temperatures near to the mold were compared, after switching off the power of microwave. The technique and mold for thin-metal part castings using ME was reported in the patent form to minimize or eliminate casting defects like porosity, cold shunts, and incomplete extensions [24–25]. The published experimental literature in processing of metallic materials using microwave energy has highlighted the potential of microwaves but with proper tooling. Therefore, this opens up the opportunity windows for the technique of MC. Next section focuses on the experimental studies related to metal casting using ME.
Transport Mechanisms and Membrane Separation Processes
Published in Mihir Kumar Purkait, Randeep Singh, Membrane Technology in Separation Science, 2018
Mihir Kumar Purkait, Randeep Singh
The plate-and-frame module assembles flat sheet membranes in a casket form. The plate-and-frame module is shown schematically in Figure 2.11. In this module, more than one membrane can be accommodated in a stacked form over one another. The feed and permeate side of the membranes face each other; it gives an impression of an individual compartment made up of a set of membranes. Spacers are placed in between these compartments and the number of the compartments or membrane sets in the module are sealed with closing rings. Lastly, the module is enclosed between plates to form a plate-and-frame stack. This finally results in the plate-and-frame module. The normal packing density that can be attained in the plate-and-frame module is in the range of 100 to 400 m2/m3. The feed is introduced in the plate-and-frame module from the feed side of the module, which travels across the membrane to the permeate channel and finally enters a common permeate channel, taking the permeant out of the module. Generally, the plate-and-frame module is used for small-scale applications due to its expensiveness and leakage problems. Plate-and-frame modules are rarely used nowadays; spiral-wound modules are more commonly used. Electrodialysis and pervaporation membrane processes are some of the processes that are still entertaining the plate-and-frame modules in high numbers. Membrane processes like ultrafiltration and reverse osmosis employ plate-and-frame modules where feed induces high fouling.
Control of Low-Concentration Volatile Organic Compound Emissions In the Wood Coating Industry — A Case Study
Published in Gregory D. Boardman, Hazardous and Industrial Wastes, 2022
York Casket Company (‘the facility’) operates a casket and furniture manufacturing plant in York, Pennsylvania. Volatile organic compound (VOC) sources at this facility were permitted under the Pennsylvania regulations. With the increased production and newly promulgated regulations under the 1990 Clean Air Act Amendments (CAAA), the plant was required to control the VOC emissions.
Weapons Radiochemistry: Trinity and Beyond
Published in Nuclear Technology, 2021
Susan K. Hanson, Warren J. Oldham
To simulate the radioactivity that would be produced during the Trinity test, an irradiated fuel element or “slug” was obtained from the Hanford Pile. The slug was irradiated for 116 days, incurring an estimated 1.8 × 1014 fissions per second. The total radioactivity contained in the 100 tons of HE was thus approximately 1.8 × 1021 total fissions, corresponding to 1000 curies of beta activity.8 The slug was shipped from Washington to Alamogordo in a lead casket and moved with a crane truck into a special dissolving tank constructed with 3-ft concrete walls lined with 8 in. of lead. The slug was dissolved in concentrated nitric acid under remote operation. Once dissolution was complete, the pH of the solution was raised by the addition of formic acid, and the solution was directly pumped into saran tubing that was threaded through the high explosive pile. A higher pH was required by explosive experts, who were concerned that an accidental leak of the acidic radioactive mixture could cause a heating reaction and premature detonation of the high explosives.8
Ground penetrating radar applications and implementations in civil construction
Published in Journal of Structural Integrity and Maintenance, 2023
Macy Spears, Saman Hedjazi, Hossein Taheri
As mentioned earlier, there are available software programs that can process GPR results to produce images. However, most of these are limited to creating 2D models. Since many recent studies involve the imaging of GPR data, there is great interest from users in producing 3D models for more advanced results. Dinh et al. investigated ways to create 3D models for concrete structures (Dinh et al., 2021). Concrete slab specimens were constructed in the lab with two layers of rebar, placed in both directions. Using 2D-SAFT and 3D-SAFT (synthetic aperture focusing technique) algorithms through MATLAB programs, the authors created 3D models of the concrete slabs from the GPR survey grid data. The 2D-SAFT algorithm involved the projection of A-scan data onto a 2D slice with correlation to the raw B-scan data, and a 2D image was produced for each survey line. However, this required interpolation to create the 3D image. Alternatively, the 3D-SAFT method projected the A-scan data of the whole set onto the reconstructed 3D area. The 3D-SAFT technique provided more accurate results since the EM waves travel in all directions. Similarly, Kelly et al. used GPR grid survey data for the creation of 3D models of cemetery burial sites with a software platform (Kelly et al., 2021). Interpolation of the radargrams was performed to produce subsurface 2D depth slices, which then created the 3D shape. From the processed data, casket identification could be made. Koyan and Tronicke created 3D GPR data for sedimentary models with a graphics processing unit (GPU) in gprMAX, which is an open-source software (Koyan & Tronicke, 2020). This means anyone has access to view the code and make any changes, as well as the ability to distribute the software. This software is based on the Finite-Difference Time-Domain method to imitate the EM wave propagation. With this, the authors were able to successfully create realistic 3D porosity models. Interpreting raw GPR data can be a challenging task, so creating 3D image results allows for an easier evaluation.