Shockwave Interaction with a Cylindrical Structure

An increased understanding of the shockwave interaction with a cylindrical structure is the foundation for developing a method to explosively seal a pipe similar to the Deepwater Horizon accident in the Gulf of Mexico. Shockwave interactions with a cylindrical structure have been a reoccurring focus of energetics research. Some of the most notable contributions of non-destructive tests are described in ``The Effects of Nuclear Weapons\u27\u27 (Glasstone, 1962). The work presented by Glasstone examines shockwave interaction from a 20-megaton bomb with a cylindrical structure. However, the data is limited to a peak overpressure of less than 25 psi, requiring several miles between the structure and the charge. The research presented in the following paper expands on the work Glasstone described by examining the shockwaves from 90, 180, and 270-gram C-4 charges interacting with a 6-inch diameter cylindrical structure positioned 52-inches from the center of the charge. The three charge weights that were tested in this research generated a peak overpressures of approximately 15, 25, and 40 psi, respectively. This research examines the peak pressure and total impulse from each charge acting on the cylindrical structure as well as the formation of vortices on the ``backside\u27\u27 of the cylinder surface. This paper describes the methodology and findings of this study as well as examines the causality and implications of its results on our understanding of the shockwave interaction with a cylindrical structure

The effects select physical parameters have on an explosively formed projectile\u27s performance

Identifying how changes in the physical parameters of an Explosively Formed Projectile (EFP) affect its performance is crucial in determining what physical parameters could be changed to achieve a desired performance. This research analyzes five of the physical parameters of an EFP, similar to an Iranian design (Worsey, 2009), and the effects on performance. The five physical parameters selected for this research were charge weight, confining geometry, flyer thickness, flyer curvature, and explosives-type. Eighteen different EFP designs were used to test the penetration, measured velocity, production of a dominant projectile, and kinetic energy of these five physical parameters. Of the physical parameters tested, the charge weight and flyer thickness affected the projectile\u27s performance the most. The author\u27s objective of this work is to use the research information contained herein to design an EFP capable of testing military armor to protect and save lives --Abstract, page iii

Explosively Formed Projectile Soft-Recovery Force Analysis

The design of a soft-recovery system is critical to a researcher\u27s ability to analyze hypervelocity projectiles. The researcher may decide to use one method over another based on several criteria, including whether or not non-deformed projectile measurements are required. This report analyzes the forces two different soft-recovery methods impart on the projectiles collected. Method 1 utilized three polyethylene water barrels placed “end-to-end” horizontally, providing 2.6 meters (9 feet) of water to stop the projectile. Method 2 is a modification of the soft-recovery method utilized in “Soft-Recovery of Explosively Formed Penetrators” by Lambert and Pope. This method utilizes a series of several materials with an increasing density gradient, placed end-to-end over 14.3 meters (47 feet) to stop the projectile. Despite the fact that explosively formed projectiles (EFPs) of the same design were fired into each recovery method, the projectiles collected using the two methods differed in shape, size, weight, and the number of pieces collected. Since the EFP designs were identical to begin with, the physical differences are most likely due to the different magnitudes of the forces exerted on the projectile during deceleration. Drag force calculations will be performed for both recovery methods in an attempt to determine the differences in the drag forces exerted on the projectile during its deceleration. The results of the calculations will assist in determining to what extent the physical deformation of the projectile is due to the material selection of each recovery method. The consistency of the shapes and weights of the recovered projectiles will also be briefly addressed to assist the researcher in choosing the most useful recovery method for a given objective

The Effects of the Flyer Plate\u27s Radius of Curvature on the Performance of an Explosively Formed Projectile

An explosively formed projectile (EFP) is known for its ability to penetrate vehicle armor effectively. Understanding how an EFP’s physical parameters affect its performance is crucial to development of armor capable of defeating such devices. The present study uses two flyer plate radii of curvature to identify the experimental effects of the flyer plate’s radius of curvature on the measured projectile velocity, depth of penetration, and projectile shape. The Gurney equation is an algebraic relationship for estimating the velocity imparted to a metal plate in contact with detonating explosives. The authors of this research used a form of the Gurney equation to calculate the theoretical flyer plate velocity. Two EFP designs that have different flyer plate radii of curvature, but the same physical parameters and the same flyer-weight to charge-weight ratio should theoretically have the same velocity. Tests indicated that the flyer plate’s radius of curvature does not affect the projectile’s velocity and that a flat flyer plate negatively affects projectile penetration and formation

Explosive Dust Test Vessel Comparison using Pulverized Pittsburgh Coal

Explosions of coal dust are a major safety concern within the coal mining industry. The explosion and subsequent fires caused by coal dust can result in significant property damage, loss of life in underground coal mines and damage to coal processing facilities. The United States Bureau of Mines conducted research on coal dust explosions until 1996 when it was dissolved. In the following years, the American Society for Testing and Materials (ASTM) developed a test standard, ASTM E1226, to provide a standard test method characterizing the “explosibility” of particulate solids of combustible materials suspended in air. The research presented herein investigates the explosive characteristic of Pulverized Pittsburgh Coal dust using the ASTM E1226-12 test standard. The explosibility characteristics include: maximum explosion pressure, (Pmax); maximum rate of pressure rise, (dP/dt)max; and explosibility index, (Kst). Nine Pulverized Pittsburgh Coal dust concentrations, ranging from 30 to 1,500 g/m3 , were tested in a 20-Liter Siwek Sphere. The newly recorded dust explosibility characteristics are then compared to explosibility characteristics published by the Bureau of Mines in their 20 liter vessel and procedure predating ASTM E1126-12. The information presented in this paper will allow for structures and devices to be built to protect people from the effects of coal dust explosions

Literature Lab: a method of automated literature interrogation to infer biology from microarray analysis

<p>Abstract</p> <p>Background</p> <p>The biomedical literature is a rich source of associative information but too vast for complete manual review. We have developed an automated method of literature interrogation called "Literature Lab" that identifies and ranks associations existing in the literature between gene sets, such as those derived from microarray experiments, and curated sets of key terms (i.e. pathway names, medical subject heading (MeSH) terms, etc).</p> <p>Results</p> <p>Literature Lab was developed using differentially expressed gene sets from three previously published cancer experiments and tested on a fourth, novel gene set. When applied to the genesets from the published data including an <it>in vitro </it>experiment, an <it>in vivo </it>mouse experiment, and an experiment with human tumor samples, Literature Lab correctly identified known biological processes occurring within each experiment. When applied to a novel set of genes differentially expressed between locally invasive and metastatic prostate cancer, Literature Lab identified a strong association between the pathway term "FOSB" and genes with increased expression in metastatic prostate cancer. Immunohistochemistry subsequently confirmed increased nuclear FOSB staining in metastatic compared to locally invasive prostate cancers.</p> <p>Conclusion</p> <p>This work demonstrates that Literature Lab can discover key biological processes by identifying meritorious associations between experimentally derived gene sets and key terms within the biomedical literature.</p

Modeling explosive lensing on a cylindrical body in air: A first step towards sealing an underwater offshore oil spill

In 2010, the British Petroleum (BP) Deepwater Horizon accident leaked oil into the Gulf of Mexico for 87 days. A fast response method that can seal an oil pipe and stop the release of oil is needed in order to prevent future oil leaks from turning into ecological and financial disasters. Explosives can serve this need. This research examined how a circular implosive discontinuous explosive lens interacts with a cylindrical surface. The following research was designed to study the applicability of the Method this author developed to predict the peak pressure from multiple shockwaves converging on a centrally located cylinder. This research also examined if multiple charges can impart a higher peak pressure or impulse on the centrally located cylindrical surface than a single charge of equal net weight. The experiments examined single charges in line with the signature sensor with various charge weights (0.2, 0.4, and 0.6 lb) and multiple 0.2 lb charges varying the number of charges (1-5) at different angular spacings (180, 120, 90, 60, and 40-degrees). The Method developed throughout this research can be used to predict the pressure along the symmetry plane when 180 ≥ 0 ≥ 60 degrees, for two and three 0.2 lb charges. The Peak Pressure Predictive Method is accurate to ± 4 percent. The techniques developed to predict the peak reflected pressure and impulse generated from multiple shockwaves converging on a cylindrical surface will aid in generating a rapid response system to help prevent underwater disasters similar to the Deepwater Horizon event --Abstract, page iii

Shockwave Uniformity Associated with Various Free Air Burst Configurations

Examination of the shockwave expansion from a free air burst (FAB) explosion. Two different geometries were examined with different suspension systems. The literature review and results illustrate how the FAB is set up affects the measurable blast pressure

Explosively Generated Pipe Collapse

This report details the initial research in determining the plausibility of using underwater explosive lensing as a means of sealing a leaking oil pipe, to mitigate the environmental damage of an event similar to the Deepwater Horizon incident. The Deepwater Horizon incident spilled 4.9 million barrels of oil into the Gulf of Mexico over the course of 152 days (Achenbach & Fahrenthold, 2010). A cement plug injected into a nearby relief well successfully capped the leaking well on September-19-2010. It is evident that rapid response systems for incidences such as this are a necessity. This report examines how an explosively generated pipe collapse compares to the critical collapse equations developed by the American Petroleum Institute (API). In this research, we calculated the API critical collapse pressure for three pipes-- a 2”, a 4”, and a 6” pipe, each with yield strength of 42,000 psi. To produce the empirical equations, API tests incrementally increased the (external) hydrostatic pressure on pipes until they failed (Kyriadkides and Corona, 2007). Therefore, we expect that the peak (impulsive, not quasistatic) pressure generated from an explosive will need to be substantially higher in order to produce results similar to those from the API tests. We will use the results of the tests to correlate the API critical collapse pressure to an explosively generated pressure. Later, we will use this correlation to determine an explosive lens configuration capable of completely (implosively) sealing the pipe, while reducing the total amount of explosives required to do so