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Impact of Well Remediation Chemicals on Water Quality and Deterioration
Published in Joseph A. Cotruvo, Gunther F. Craun, Nancy Hearne, Providing Safe Drinking Water in Small Systems, 2019
In 1996 the city performed an Airburst redevelopment process in conjunction with passive chemical addition. It required well pump removal allowing development of the well screen area and cleaning of the gravel pack and surrounding formation with air bubbles and chemicals. The process consists of sudden release of high-pressure compressed air or nitrogen gas from a 14-cubic-inch firing chamber that is lowered and raised within the well. The rapid release of 3,000 psi air from four portholes of the airgun chamber loosens surface debris as it rapidly expands 200 times in volume out through the screens to force cleaning/disinfection chemicals into the formation. This explosive release at high pressure provides acoustical output with high energy yield in the most useful seismic frequencies. Airburst purports safer coverage of the entire screened area with greater intensity and frequency than other explosive or sonic-type devices [Frazier, 1997].
Experimental and numerical study on dynamic response of V-shaped hull subjected to mine blast
Published in Mechanics Based Design of Structures and Machines, 2022
Kingery and Bulmash [11] performed a series of blast experiments so as to investigate behavior of structures under blast loading. Various amounts of TNT explosive with the shape of sphere and hemisphere were detonated at different standoff distances to the target plate to obtain blast parameters. These parameters were then used to formulate the linear polynomial equation of states, which are the basis of CONWEP computer program (U.S. Army Corps of Engineers 2002, 2008). CONWEP is implemented in LS-DYNA as *LOAD_BLAST function. This card defines an airblast function for the application of pressure loads due to explosives in conventional weapons and it can be used for airburst of a spherical high explosive, ground detonation of a charge or surface burst of a hemispherical high explosive. The implementation is based on a report by Randers-Pehrson and Bannister (1997) where it is mentioned that this model is adequate for use in engineering studies of vehicle responses due to the blast from landmines. The accuracy of LOAD_BLAST has been assessed in the study of Rigby et al. (2014). The authors found out in their study that the blast parameters obtained in the experimental measurements are generally predicted to a high degree of accuracy by the CONWEP method. The maximum deviation between the experimental measurements and CONWEP predictions is about 7%. The authors also concluded that the method is very accurate and can be utilized with confidence as a first-order approach for quantifying the blast load acting on a structure through drawing comparison among other blast simulation techniques. For this reason, mesh sensitivity study has been carried out on the basis of CONWEP model.