Water Gun Research Articles

Steepest descent integration: A novel method for computing wavefields radiated from borehole sources

Borehole sources, including chemical explosives, air gun, water gun, and piezoelectric transducers in the borehole, generate seismic waves inside and outside the borehole. Modeling the wavefield is of key importance in acoustic logging, crosshole tomography, mining geophysics, and deep sounding seismic for interpretation of amplitude information of real data and prediction of energy-radiation patterns. Classic methods for modeling the wavefield inside a borehole, such as real-axis integration, are challenged by highly oscillatory integrals encountered when modeling the wavefield outside the borehole. We have developed a novel method, called steepest descent integration (SDI), which evaluates the oscillatory wavenumber integration by numerically integrating along the steepest descent path. The oscillation along the new integration path is significantly reduced. The contributions of poles and branch cuts are added if they are located between the steepest descent path and the real axis. The SDI is applicable to arbitrary frequency and source-receiver distance. Comparison with real-axis integration shows that the method can compute highly oscillatory integrals with better efficiency and accuracy. In addition, the SDI is more numerically robust because it generates no spurious arrivals, which are evident in the real-axis integration. Analysis of numerical examples at different source-receiver distance shows that SDI is more efficient when computing far-field seismograms. This SDI can also be used to compute highly oscillatory integral in other wave-propagation problems.

Water guns affect abundance and behavior of bigheaded carp and native fish differently

Water guns have shown the potential to repel nuisance aquatic organisms. This study examines the effects of exposure to a 1966.4 cm3 seismic water gun array (two guns) on the abundance and behavior of Bighead Carp Hypophthalmichthys nobilis, Silver Carp H. molitrix (collectively referred to as bigheaded carp) and native fishes (e.g., Smallmouth Buffalo Ictiobus bubalus). Water guns were deployed in a channel that connects the Illinois River to backwater quarry pits that contained a large transient population of bigheaded carp. To evaluate the effect of water guns, mobile side-looking split-beam hydroacoustic surveys were conducted before, during and between replicated water gun firing periods. Water guns did not affect abundance of bigheaded carp, but abundance of native fish detected during the firing treatment was 43 and 34% lower than the control and water guns off treatments, respectively. The proximity of bigheaded carp to the water gun array was similar between the water guns on and water guns off treatments. In contrast, the closest detected native fish were detected farther from the water guns during the water guns on treatment (mean ± SE, 32.38 ± 3.32 m) than during the water guns off treatment (15.04 ± 1.59 m). The water gun array had a greater impact on native fish species than on bigheaded carp. Caution should be taken to the extrapolation of these results to other fish species and to fish exposed to water guns in different environments (e.g., reduced shoreline interaction) or exposure to a larger array of water guns, or for use of water guns for purposes other than a barrier.

Experiments on the sound transmission at the water-air interface for different source-interface distances

The water-air interface is a nearly perfect reflecting boundary for acoustic waves due to the high impedance contrast between the two media. In many marine applications, ranging from geophysical measurements to bioacoustics, the sea surface has an important impact. A rough sea surface topography leads to complex scattering and interference for acoustic frequencies with similar wavelength or higher than the wavelength of the interface. In geophysical applications and infrasound the frequencies of interest often have larger wavelengths. At the same time, the source within these applications is mostly located close to the interface with respect to its wavelength. In this case, an increased transmission could be expected as experiments with acoustic transducers demonstrate [D. C. Calvo et al., J. Acoust. Soc. Am. 134, 3403-3408 (2013)]. We design two experiments with sources close to the interface while changing the distance between the source and the water-air surface. For the first experiment, a water gun, which creates large cavities, is placed in water. Second, a signal gun, as used in athletics, is positioned in air. The acoustic transmission from both sides is measured and investigated. We find an increasing transmission coefficient for lower frequencies and decreasing distance between source and interface.

Art-Making as Social Justice in Za'atari and Calais

In late February 2016, French authorities entered “the Jungle”—an unofficial migrant settlement in the port town of Calais—equipped with tear gas, water guns, and bulldozers to demolish the souther...

Development of Countermeasure System of Harmful Birds in Veranda

A system to repel the bird is proposed. Harmful bird pollute the living environment of human by droppings and lay eggs on the veranda. In this study, we have developed a system that repel birds which gather on the veranda by a water gun equipped device, the proposed system detects the birds from camera image by image processing. The proposed device rotates the water gun vertically and horizontally so that it can aim to the target correctly. Therefore, the system is able to repel birds who exist within a predetermined range of veranda. Also, in the system of the study, since the device equipped by a water gun, user can fill the water in advance, it can be used in place where has no faucet.

Response of Bighead Carp and Silver Carp to Repeated Water Gun Operation in an Enclosed Shallow Pond

AbstractThe Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix are nonnative species that pose a threat to Great Lakes ecosystems should they advance into those areas. Thus, technologies to impede Asian carp movement into the Great Lakes are needed; one potential technology is the seismic water gun. We evaluated the efficacy of a water gun array as a behavioral deterrent to the movement of acoustic‐tagged Bighead Carp and Silver Carp in an experimental pond. Behavioral responses were evaluated by using four metrics: (1) fish distance from the water guns (D); (2) spatial area of the fish's utilization distribution (UD); (3) persistence velocity (Vp); and (4) number of times a fish transited the water gun array. For both species, average D increased by 10 m during the firing period relative to the pre‐firing period. During the firing period, the spatial area of use within the pond decreased. Carp were located throughout the pond during the pre‐firing period but were concentrated in the north end of the pond during the firing period, thus reducing their UDs by roughly 50%. Overall, Vp decreased during the firing period relative to the pre‐firing period, as fish movement became more tortuous and confined, suggesting that the firing of the guns elicited a change in carp behavior. The water gun array was partially successful at impeding carp movement, but some fish did transit the array. Bighead Carp moved past the guns a total of 78 times during the pre‐firing period and 15 times during the firing period; Silver Carp moved past the guns 96 times during the pre‐firing period and 13 times during the firing period. Although the water guns did alter carp behavior, causing the fish to move away from the guns, this method was not 100% effective as a passage deterrent.Received August 6, 2014; accepted January 16, 2015

The Effects of Pulse Pressure from Seismic Water Gun Technology on Northern Pike

AbstractWe examined the efficacy of sound pressure pulses generated from a water gun for controlling invasive Northern Pike Esox lucius. Pulse pressures from two sizes of water guns were evaluated for their effects on individual fish placed at a predetermined random distance. Fish mortality from a 5,620.8‐cm3 water gun (peak pressure source level = 252 dB referenced to 1 μP at 1 m) was assessed every 24 h for 168 h, and damage (intact, hematoma, or rupture) to the gas bladder, kidney, and liver was recorded. The experiment was replicated with a 1,966.4‐cm3 water gun (peak pressure source level = 244 dB referenced to 1 μP at 1 m), but fish were euthanized immediately. The peak sound pressure level (SPLpeak), peak‐to‐peak sound pressure level (SPLp‐p), and frequency spectrums were recorded, and the cumulative sound exposure level (SELcum) was subsequently calculated. The SPLpeak, SPLp‐p, and SELcum were correlated, and values varied significantly by treatment group for both guns. Mortality increased and organ damage was greater with decreasing distance to the water gun. Mortality (31%) by 168 h was only observed for Northern Pike exhibiting the highest degree of organ damage. Mortality at 72 h and 168 h postexposure was associated with increasing SELcum above 195 dB. The minimum SELcum calculated for gas bladder rupture was 199 dB recorded at 9 m from the 5,620.8‐cm3 water gun and 194 dB recorded at 6 m from the 1,966.4‐cm3 water gun. Among Northern Pike that were exposed to the large water gun, 100% of fish exposed at 3 and 6 m had ruptured gas bladders, and 86% exposed at 9 m had ruptured gas bladders. Among fish that were exposed to pulse pressures from the smaller water gun, 78% exhibited gas bladder rupture. Results from these initial controlled experiments underscore the potential of water guns as a tool for controlling Northern Pike.

Eye Injury Risk from Water Stream Impact: Biomechanically Based Design Parameters for Water Toy and Park Design

Purpose: Interactive water displays are becoming increasingly popular and can result in direct eye contact. Therefore, the purpose of this study is to investigate eye injury risk from high speed water stream impacts and to provide biomechanically based design parameters for water toys and water park fountains.Methods: An experimental matrix of 38 tests was developed to impact eight porcine eyes with water streams using a customized pressure system. Two stream diameters (3.2 mm and 6.4 mm) were tested at water velocities between 3.0 m/s and 8.5 m/s. Intraocular pressure was measured with a small pressure sensor inserted through the optic nerve and used to determine the injury risk for hyphema, lens dislocation, retinal damage, and globe rupture for each impact.Results: Experimental water stream impacts created a range of intraocular pressures between 3156 mmHg and 7006 mmHg (61 psi to 135 psi). Injury risk varied between 4.4%–27.8% for hyphema, 0.0%–3.0% for lens dislocation, and 0.1%–3.3% for retinal damage. All tests resulted in 0.0% injury risk for globe rupture. The two water stream diameters did not result in significantly different water stream velocities (P = 0.32); however, the variation in water stream diameter did result in significantly different intraocular pressures (P = 0.03) with higher pressures for the 6.4 mm stream.Conclusions: This is the first study to experimentally measure intraocular pressure from high speed water stream impacts and quantify the corresponding eye injury risk. It is recommended that toy water guns and water park fountains use an upper threshold of 8.5 m/s for water stream velocities to minimize the risk of serious acute eye damage from impacts.

Analysis on the occupational poisoning case of trichloroethylene reported in Dongguan during 2002 to 2009

To understand the demographic, occupational and clinic characteristics of occupational poisoning case due to trichloroethylene in Dongguan in recent years for the purpose of prevention. Using the trichloroethylene patients of poisoning diagnosed in the years between 2002 to 2009 as subjects, their age, sex, industry, job, working duration and exposure level were analysed. In Dongguan between 2002 and 2009 altogether 82 cases were reported, among the 82 cases 8 patients were dead with case fatality rate of 9.8%. among them there were 12 cases of poisonings(8 females ,4 males); 9 cases were classified as mild poisonings and the rest serious ones, among the 12 cases 3 patients were dead with case fatality rate of 25.0%; Dermatitis caused by TCE there were 70 cases (37 males and 33 females), among the 70 cases 5 patients were dead with case fatality rate of 7.1%. 11 persons (91.7%) were engaged in the job of cleaning and 1 (8.3%) in water gun, and they performed the job only for 3 days in shortest and for 450 days in longest. The cases were distributed in the jobs as the following: 29 (41.4%), 12 (17.1%), 8 (11.4%), 5 (7.1%), 4 (5.7%), cases respectively in the job of cleaning, parts hanging, board washing, painting, gun water spraying; a job duration of 1-50 d (27.4 days in average). In summary the TCE poisonings in Dongguan were two types of poisoning, i.e., systematic poisonings and drug rash-like dermatitis, occupational TCE poisonings took place mainly in the cleaning workers. Dermatitis caused by TCE can cure but hard to prevent, we should strengthen the early examination of new works.

Ladies' Night at the Shooting Range

On my eighth birthday, my father brought my gift in from the garage. Camouflage flecked the box. A girl cast a fishing line, and a river rolled away from her. A wide-mouthed trout leaped into the horizon. A turn of bad luck involving my scalp and a stray hook had left me leery of the sport. I stared at the box. Open it, he said. I slid apart the mouth of the box. Plastic mock wood and a cold metal barrel, its stock the color of chestnuts. Antiqued scrawling etched into the receiver. I felt the gun's balance in my palms. Tied to the barrel hung a pack of bbs, shining and silver like tiny comets. I swung the gun to my shoulder and closed one eye, just as I'd seen my father do. The trigger curved against my finger. I hadn't asked for an air rifle, but this was the year I discovered The Good, The Bad, and the Ugly. My brother and I watched Clint Eastwood squint and smoke his cigar, his hand never far from his six-shooter. We took to our pasture, paced off, and pointed our water guns.

Development of Alternative Projectile to Deactivate an Improvised Explosive Device - Pipe Bomb

The article describes a possibility of dealing with the problem represented by an improvised explosive device in the form of a pipe bomb so that the problem may be solved quickly and reliably, i.e. so that the pipe bomb may be deactivated without explosion. The article describes the development of an alternative projectile that will replace the water content in the water gun; thus it will make it possible to remove metallic end caps closing pipe bombs so that the bombs can be disassembled without explosion, and subsequently to subject the dismantled parts to forensic examination to detect a designer of the improvised pipe bomb.

An integrated fire detection and suppression system based on widely available video surveillance

An integrated system based on video surveillance is presented for automatic fire detection and suppression. The system is composed of two modules, including fire detection and fire suppression. The fire detection module makes full use of traditional CCD cameras for fire recognition. Some spatio-temporal features, such as color and motion, are extracted to detect fire in real time by utilizing sequential image processing techniques. Once a fire is detected, the system will control the fire suppression module to extinguish the fire automatically. It mainly consists of control device, mobile device, and water gun. Experiments performed in a large space hall show that the integrated system can detect a fire about a few seconds after ignition and automatically suppress the fire quickly.

The Big Splash (review)

Reviewed by: The Big Splash Elizabeth Bush Ferraiolo, Jack D. The Big Splash. Amulet/Abrams, 2008 [288p] ISBN 978-0-8109-7067-0 $15.95 Reviewed from galleys R Gr. 5–8 Vinnie Biggio was once every bully’s victim, but for the past year he’s been the capo of the Franklin Middle School underworld, running operations in everything from plagiarized reports to contraband candy. In a stunning turn of events, his most feared enforcer, Nikki “Fingers” Finnegan, has been shot down in the hall, a victim of her own m.o.—public pants-soaking with a water gun—in a humiliation from which no middle-schooler recovers. It’s up to Matt Stevens, the Philip Marlowe of “the Frank,” to bring Nikki’s assailant to justice without taking a socially fatal squirt to the crotch himself. Ferraiolo shines in this debut novel, working the noir tropes for all they’re worth, from the cleverly typecast students (hard-boiled reporters and shady dames) to the profusion of sardonic similes (“Gretchen was like a poorly fed show poodle: pretty, well groomed, and mean”). This is no slick gimmick: Ferraiolo doesn’t exaggerate by much when he parallels junior-high character assassination with taking a bullet; as middle-schoolers know, either can wipe your name from the social roster. Moreover, the mystery itself is cagily constructed to keep readers guessing pretty much ’til the last bell. A couple of enigmas are left unresolved, and they’re significant enough to leave readers expecting a sequel. Ferraiolo better cough up the goods or watch his back. Copyright © 2008 The Board of Trustees of the University of Illinois

A practical example aiding understanding momentum in 1D: the water gun experiment

The law of conservation of momentum is one that students often have difficultiesunderstanding. This experiment allows students to use childhood toys to examine andcalculate the muzzle velocity of their favourite water gun by using an air track, a sparktimer or data logger and the law of conservation of momentum in a one-dimensional case, amodification of the standard ballistic pendulum laboratory experiment (1990 Physics 100Lab Manual St Francis Xavier University).

Rank-based estimation for all-pass time series models

An autoregressive-moving average model in which all roots of the autoregressive polynomial are reciprocals of roots of the moving average polynomial and vice versa is called an all-pass time series model. All-pass models are useful for identifying and modeling noncausal and noninvertible autoregressive-moving average processes. We establish asymptotic normality and consistency for rank-based estimators of all-pass model parameters. The estimators are obtained by minimizing the rank-based residual dispersion function given by Jaeckel [Ann. Math. Statist. 43 (1972) 1449–1458]. These estimators can have the same asymptotic efficiency as maximum likelihood estimators and are robust. The behavior of the estimators for finite samples is studied via simulation and rank estimation is used in the deconvolution of a simulated water gun seismogram.

Maximum likelihood estimation for all-pass time series models

An autoregressive-moving average model in which all roots of the autoregressive polynomial are reciprocals of roots of the moving average polynomial and vice versa is called an all-pass time series model. All-pass models generate uncorrelated (white noise) time series, but these series are not independent in the non-Gaussian case. An approximate likelihood for a causal all-pass model is given and used to establish asymptotic normality for maximum likelihood estimators under general conditions. Behavior of the estimators for finite samples is studied via simulation. A two-step procedure using all-pass models to identify and estimate noninvertible autoregressive-moving average models is developed and used in the deconvolution of a simulated water gun seismogram.

Combinatorial Electrodeposition of Ternary Cu–Sn–Zn Alloys

Active-inactive alloy systems (such as Cu–Sn–Zn) have been proposed to replace graphitic negative electrodes in commercial lithium-ion batteries due to their high theoretical capacity and relatively good cyclability. The performance of these electrode materials is largely determined by their composition. Identifying the optimal composition that provides both large capacity and good cyclability requires the testing of tens, hundreds or even thousands of different alloys. Combinatorial deposition and screening techniques lend themselves well to this kind of optimization study. Galvanostatic deposition in an electrochemical Hull cell is used to fabricate a composition-spread film of binary Sn–Zn alloys. A second step involving a water gun and weak copper sulfate solution is used to achieve a composition spread film of ternary Cu–Sn–Zn alloys. Energy-dispersive spectroscopy and X-ray diffraction are used to characterize the electrodeposited films. The significance and uniqueness of this work is illustrated by our ability to perform combinatorial material science simply and inexpensively. In addition, a phenomenological model is presented to describe the deposition process. The success of the phenomenological model demonstrates we have an understanding, albeit rudimentary, of the immersion deposition process.

Sediments in the East China Sea

This paper describes measurements of sediments during the 2000-2001 Asian Seas International Acoustic Experiment in the East China Sea. A number of techniques were used to infer properties of these sediments, including gravity and piston cores, subbottom profiling using a water gun, long-range sediment tomography, and in situ measurement of conductivity. Historical data from echosounder records and cores showed two regions of surficial sediments in the experimental area: a silty area to the west and a sandy area to the east. The tomography, cores, and water-gun measurements confirm the two surficial sediment regions seen in the historical data and also indicate that the subbottom structure at the experimental site consists of a thin (0-3 m thick) layer of sandy sediment directly beneath the sea floor. Below this layer, there is an extensive package of sediment with relatively uniform acoustic attributes. Core analysis shows that the surface sediment layer varies in compressional wave speed from a low near 1600 m/s in the west side of the experiment area to 1660 m/s in the east side of the experiment area. Long-range sediment tomography inversions show a similar spatial variation in the surface layer properties. In addition, the layer thickness as determined from tomography is consistent with the estimates from subbottom profiling.

A Preliminary Discussion on Selecting Active Fire Protection Systems for Atria in Green or Sustainable Buildings

Sprinkler systems are a common fire protection strategy used in shopping malls, whether there is an atrium or not. Because of the typically high headroom in an atrium, it is often difficult to activate a sprinkler due to a fire at the floor level. Further, flooding the atrium floor with excessive water from a sprinkler can affect evacuation and can cause serious property damage. Sprinkler systems do not satisfy the water conservation criterion for green or sustainable buildings. Alternative systems using less water should be designed for a ‘green or sustainable’ shopping mall with an atrium. The alternative active fire protection systems proposed in this paper are: • Water gun in atrium spaces; • Intelligent fire detection systems in atria; • Water mist fire suppression systems in shops adjacent to an atrium. An atrium in a ‘green or sustainable’ shopping mall is taken as an example. The feasibility of using the above fire protection systems is discussed. The potential advantage of less water use for green or sustainable buildings will be pointed out. Further, designing static smoke exhaust with roof vents for protecting the atrium with minimum use of electric power will be outlined, bearing in mind that a smoke management system is also regarded as an active fire protection system in some countries.

Anthropogenic sound and marine mammal health: measures of the nervous and immune systems before and after intense sound exposure

Anthropogenic sound is a potential stressor for marine mammals that may affect health, as has been demonstrated in other mammals. Therefore, we have initiated investigations on the effects of intense underwater sounds on nervous system activation and immune function in marine mammals. Blood samples were obtained before and after sound exposures (single underwater impulsive sounds (up to 200 kPa) produced from a seismic water gun and (or) single pure tones (up to 201 dB re 1 μPa) resembling sonar “pings” from a white whale, Delphinapterus leucas, and a bottlenose dolphin, Tursiops truncatus, to measure neural-immune parameters. Norepinephrine, epinephrine, and dopamine levels increased with increasing sound levels and were significantly higher after high-level sound exposures (>100 kPa) compared with low-level sound exposures (<100 kPa) or controls (P = 0.003, 0.006, and 0.020) for the white whale. Alkaline phosphatase decreased over the experimental period (P < 0.001), while γ-glutamyltransferase increased over the experimental period (P < 0.001). Significant neural-immune measurements for the dolphin after exposure to impulsive sounds included an increase in aldosterone (P = 0.003) and a decrease in monocytes (P = 0.006). Neural-immune changes to tonal sound exposures were minimal, although changes were observed in multiple neural-immune measures over time.