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The New Hondsbossche Dunes
Published in Elizabeth Mossop, Sustainable Coastal Design and Planning, 2018
Adriaan Geuze, Edzo Bindels, Riette Bosch
Extensive sand calculations and coastal modeling led to the addition of 35.6 million cubic meters (m3) of sand (enough to fill 400 football fields), placed between January 2014 and January 2016, using trailing suction hopper dredgers and spraying boats. These boats feature large, powerful pumps and engines that enable them to dredge sand, clay, sludge, and even gravel from sea or river beds. The vessel stores the dredged material in its own hopper and discharges the leftover water overboard. The hopper can be emptied in a variety of ways, including by depositing the material through doors or valves on the bottom of the vessel; using pumps and jets to make the material fluid again and pump it ashore through a pipeline; or spraying, where the hopper contents are pumped directly from the vessel to the desired site.
Storage and Conveying of Bulk Solids
Published in Enrique Ortega-Rivas, Unit Operations of Particulate Solids, 2016
Open-yard or structured storage may be only a part of a bulk solids handling facility. Due to processing requirements, there is normally the need of having an intermediate storage system which may be directly connected to a processing line. In some other cases, the storage capacity would not involve large tonnages and, therefore, confined storage would be an obvious choice. Furthermore, considering finely divided solids that are subjected to erosion by wind or rain, piling cannot be taken as a feasible manner of storage and, therefore, all these particulate systems may be most properly kept in containers or vessels known also as silos, but alternatively termed as bins and hoppers. In this case, a silo is tall and relatively small in diameter, while a bin is usually not so tall and fairly wide. A hopper is a small bin with a sloping bottom, for temporary storage of solids prior to be fed into a particular process. Normally, the lower part of a silo in a shape of a cone or inverted pyramid is also called a hopper. Generally, all these containers are loaded from the top and discharged from the bottom. A major problem in bin design is related to proper and controllable discharge.
Hot-Melt Application Equipment
Published in Gerald L. Schneberger, Adhesives in Manufacturing, 2018
Two major hopper configurations are available. One design, the “cool” hopper, keeps the material relatively unaffected by heat before it reaches the grid. The other, the “warm” hopper, utilizes the heat radiation from the grid for a stage-type melting process.
A novel design to external filament extruder for 3D printer
Published in Australian Journal of Mechanical Engineering, 2021
Amal Nassar, Eman Nassar, Mona Younis
In order to produce parts have high corrosion resistant Steel 304 with a composition of (Fe 08, C 17.5, Cr 20, Ni 11, Mn 2, Si 1, P0 45, S 03) was selected to make the screw. Figure 4 shows the prediction of temperature distribution during the extruded process, the model was made using the program (FEHT 4). The program developed by the University of Wisconsin – Madison. In the simulation process, 540 nodes were used with 970 triangular elements. Inlet temperature is set at 25 c, the cylinder temperature is set at 105 C and screw temperature is set at 50 c, the program ignore convection .thermal conductivity of the steel 304 is taken as 14 W/m.K. the prediction model confirm that thermal conductivity of the selected material (steel 304) can lead to high temperature during extruded process(Paul Gramann 1998). The program validated by measuring the actual temperature at three locations: at the inlet; at the middle of the extruder and at extruder outlet. In order to measure the temperature laser surface thermometer (Maverick LT-02) was used. Aluminum sheet with thickness 2 mm was used to make the cylinder, Brass was used to making the Nozzle. The connection joint between hopper and extruder was made from Teflon since it is an excellent insulator and has a high melting temperature (260 C). Hopper made with a material easy to manufacture, light in weight and resistant to temperature, so it is fabricated in Polypropylene. Figure 7 illustrates temperature distribution during extruded for the selected material.
Additive manufacturing of bimetallic structures
Published in Virtual and Physical Prototyping, 2022
Amit Bandyopadhyay, Yanning Zhang, Bonny Onuike
Instead of pre-mixing powders in an external mixer before loading the blend into a single powder hopper, each powder is loaded into different hoppers, as most modern DED systems are equipped with multiple powder feeders. These powders are automatically mixed on the fly during the deposition, either at an integral mixing unit along the intersection of the powder delivery lines or the deposition head. This process is called dynamically mixing, where the bimetallic material’s composition is varied through powder flow rate controlled by the powder feeder motors. For instance, hopper 1 is filled with powder material A, and hopper 2 is filled with powder B, then a 50/50 wt % of materials A and B can be deposited when the powder feeder motors are set to the same operational feed rate. Likewise, by increasing one of the motor’s speeds and decreasing the other accordingly, the bimetallic material’s composition can be varied as desired. Both Sahasrabudhe et al. 2015) and Reichardt et al. (2016) used this technique to fabricate bimetallic structures of titanium alloy (Ti64) and stainless-steel materials. Likewise, functionally graded alloy of SS304L and Inconel 625 materials (Carroll et al. 2016) and bimetallic joint of Ti6Al4V + Al12Si materials were fabricated via a dynamically mixing process (Zhang and Bandyopadhyay 2019). The input motor feed rate (rev/min) is typically calibrated to the powder flow rate in g/min experimentally to estimate the percentage composition by weight of each powder material in the mixture during deposition. However, such estimation is usually inaccurate after deposition because not all the powder materials blown into the melt pool region are melting. Some are blown off based on density variation. Such powders are mostly seen as waste/unused powders around the build chamber. Hence, post-process characterisation is essential to fully quantify materials’ percentage composition along the graded section of the part. This is one of the demerits of the dynamically mixing approach during FGMs processing.
The discrete element method in silo/bin research. Recent advances and future trends
Published in Particulate Science and Technology, 2020
Hoppers are used for storing and delivering stored materials at a controlled rate. There are many applications in industry (chemical, pharmaceutical, food, agricultural…), and accurate predictions of the discharge rate are critical.