Copper Shot Research Articles

The Need to Intensify Research Efforts in the Alternative to Lead Shot

The problem of lead poisoning resulting from the use of lead shot in hunting waterbirds and shooting sports has led to the partial ban, voluntary restriction and complete ban of lead shot in some countries. The ban resulted in the alternatives like copper shot, tungsten-tin shot, bismuth-tin, steel shot, etc. These alternatives are still expensive and other possible alternatives have not been explored up to date. There is therefore need to ban lead shot world-wide and step up research into the alternatives (green shot).

Analysis of spatially resolved Z-pinch spectra to investigate the nature of “bright spots”

Localized, intensely radiating regions are often observed in Z pinches. High resolution images of such areas have been recorded at least as far back as the 1970s. However, there is as yet no widely accepted consensus on the nature of these “bright spots” or how they are formed. This phenomenon has also been referred to “hot spots” or “micropinches.” To shed further light on this issue, we have analyzed axially resolved K-shell spectra from 4 Z pinches driven by the refurbished Z generator (“ZR”) at Sandia National Laboratories, and the previous version of the Z machine (“Z”). The atomic numbers of the loads varied from 13 to 29. We find that higher spatial K-shell intensity in the Al pinch correlates with density. The K-shell intensity within a copper shot taken on ZR correlates strongly with increased electron temperature, but another, somewhat less well-diagnosed copper shot from Z shows correlation with density. The bright spots in a Ti pinch correlate with neither density nor temperature, but do correlate with the product of density and diameter (proportional to opacity). This opacity correlation is also observed in the other 3 pinches.

Release of copper from sintered tungsten–bronze shot under different pH conditions and its potential toxicity to aquatic organisms

Sintered tungsten-bronze is a new substitute for lead shot, and is about to be deposited in and around the wetlands of North America. This material contains copper in the alloyed form of bronze. This in vitro study was performed according to U.S. Fish and Wildlife Service criteria to determine the dissolution rate of copper from the shot, and to assess the toxic risk that it may present to aquatic organisms. The dissolution of copper from tungsten-bronze shot, pure copper shot, and glass beads was measured in a buffered, moderately hard, synthetic water of pH 5.5, 6.6, and 7.8 over a 28-day period. The dissolution of copper from both the control copper shot and the tungsten-bronze shot was affected significantly by the pH of the water and the duration of dissolution (all p values<0.000). The rate of copper release from tungsten bronze shot was 30 to 50 times lower than that from the copper shot, depending on pH (p<0.0000). The observed expected environmental concentration of copper released from tungsten-bronze shot after 28 days was 0.02 microg/L at pH 7.8, and 0.4 microg/L at pH 5.6, using a loading and exposure scenario specific in a U.S. Fish and Wildlife Service protocol. Ratio Quotient values derived from the highest EEC observed in this study (0.4 microg/L), and the copper toxic effect levels for all aquatic species listed in the U.S. Environmental Protection Agency ambient water quality criteria database, were all far less than the 0.1 criterion value. Given the conditions stipulated by the U.S. Fish and Wildlife Service and the U.S. Environmental Protection Agency, heavy loading from discharged tungsten-bronze shot would not pose a toxic risk to potable water, or to soil. Consequently, it would appear that no toxic risks to aquatic organisms will attend the use of tungsten-bronze shot of the approved composition. Given the likelihood that sintered tungsten-bronze of the same formula will be used for fishing weights, bullets, and wheel balance weights, it is expected that the use of this new material in these applications will not be associated with toxic risks to aquatic life.

Structures and Bonding Nature of Small Monoligated Copper Clusters (HCN−Cun,n= 1−3) through High-Resolution Infrared Spectroscopy and Theory

The structures, C-H stretching frequencies, and dipole moments of HCN-Cun (n = 1-3) clusters are determined through high-resolution infrared spectroscopy. The complexes are formed and probed within superfluid helium droplets, whereby the helium droplet beam is passed over a resistively heated crucible containing copper shot and then through a gas HCN pickup cell. All complexes are found to be bound to the nitrogen end of the HCN molecule and on the "atop site" of the copper cluster. Through the experimental C-H vibrational shifts of HCN-Cun and ab initio calculations, it was found that the HCN-metal interaction changes from a strong van der Waals bond in n = 1 to a partially covalent bond in HCN-Cu3. Comparisons with existing infrared data on copper surfaces show that the HCN-Cun bond must begin to weaken at very large copper cluster sizes, eventually returning to a van der Waals bond in the bulk copper surface case.

Granular-bed filtration assisted by filter cake formation 3. Penetration of filter cakes by a monodisperse aerosol

For several types of granular solids (sands, silicon carbide and copper shot), penetrations have been measured for a monodisperse aerosol (1.1 μm Dow microspheres) passing through fly ash deposited upon horizontal surfaces of the solids. Fractional penetrations can run as low as 10 −5. Pressure drop data for dust cake/granular medium combinations are also given. The data illustrate significance of dust autohesivitiy and dust/granular solid adhesivity for granular-bed filtration assisted by dust cake formation.

Sample preparation for total nitrogen and 15N‐ratio analysis by the automated Dumas combustion method

Dry combustion based on the Dumas (1831) method has become increasingly popular for total nitrogen (N) and isotope‐ratio analyses. However, the lack of sample homogeneity with soil and plant samples is often the limiting factor for the accuracy and precision of this method. Moreover, water samples are not directly analyzed by the Dumas method on a routine basis. The objective of this study was to develop an adequate sample preparation protocol for plant and water samples to be analyzed for their total N and 15N‐ratios by the Dumas method. Twenty‐four corn (Zea mays L.) samples were randomly selected, dried at 60°C, and finely ground. Plant samples were analyzed for total N by the traditional Kjeldahl and Dumas methods. Seven preparations of subsurface drainage and standard nitrate (NO3)‐N solution samples were similarly analyzed for their total N content. The effects of reducing agent (copper wire or shot) used on total N and 15N isotope ratios were also investigated in this study. The average percent total N of plant material as determined by the Kjeldahl and Dumas methods were 0.762 and 0.772, respectively, and were not statistically significantly different. The Dumas method failed to recover 25% of the NO3‐N of a drainage effluent, but exhibited recoveries as high as 97% when standard NO3‐N solutions were added. The small copper shot yielded 60 ug higher total N and 0.0074 lower atom percent 15N values for the drainage plus standard NO3‐N samples when compared to when copper wire was used. The Dumas method failed to yield adequate total N values for the drain water samples. Further research is needed regarding total N analyses of water samples by the Dumas method.

The effect of small particles on fluid turbulence in a flat-plate, turbulent boundary layer in air

This paper describes the result of both an experimental and an analytical investigation of the response of a two-dimensional, turbulent boundary layer in air to the presence of particles. Copper shot, 70 μm in diameter, were uniformly introduced into a vertical boundary layer, at a momentum thickness Reynolds number of about 1000. The particle mass flux was set at 20% of the fluid mass flux, and all measurements were made using a single-component, forward-scatter laser Doppler anemometer. The measurements clearly demonstrated that the particles damped fluid turbulence, apparently affecting all scales equally. The measurements further showed a strong correlation between the degree of damping and the particle concentration in the log region of the boundary layer.

Solid absorbent method for sampling and analysis of nitrogen dioxide in ambient air.

A sampling and analysis system was developed for measuring concentrations of nitrogen dioxide in ambient air. Copper shot was found to be an effective absorbent for collecting samples at ambient levels. The analytical system was based on the desorption of the sample from the copper by heating in a hydrogen carrier stream. The desorbed sample was then determined by a combination of catalytic pyrolysis, which converted it to ammonia, and a Coulson Conductivity Detector. Data are presented showing overall recovery, effects of storage of collected samples, results for 24-hour sampling and interferences. Studies indicated the feasibility of the method for short time sampling as well as for 24-hour sampling periods. The detection limit was shown to be as little as 100 ng NO2 in laboratory studies. This solid absorbent method provides a simple, convenient, and compact means for air sampling.

Limiting factors in gas-fluidized bed heat transfer

Factors controlling the maximum achievable rates of heat transfer between a wall surface and a fluidized bed have been further studied. Particle packing density and movements close to the heat transfer surface are of overriding importance. Experiments were carried out in a pressurized flowing packed bed to vary the gas kinematic viscosity and to control the particle residence times more precisely than is possible in a fluidized bed. Despite the interpretation of an earlier experiment, the kinematic viscosity was found to have a negligible effect on the rates of heat transfer for beds of smaller particles (< 500 μm). For such materials, maximum coefficients obtained in a pressurized fluidized bed were consistently lower than those in the flowing packed bed apart from one test when the particles had become contaminated with oil. The static pressure had an important effect on the heat transfer rates to fluidized beds of larger, closely sized particles. The quality of fluidization of beds of large dense particles appeared to improve as the static operating pressure was raised and it is also thought that conditions were being reached under which significant interphase heat transfer by fluid convection could occur. Heat transfer coefficients to beds of 625-μm copper shot nearly doubled as the operating pressure was increased from 1 to 10 atmospheres. With smaller particles the pressure effect was negligible. These results show that it is possible to achieve higher rates of heat transfer to beds of large particles than small when working at higher static pressures.

A continuous-flow reactor for the precipitation of tellurium

AbstractTellurium can be recovered from leach solutions of copper refinery slimes by precipitation as copper telluride:Te(OH)6 + 5Cu + 3H2SO4 = Cu2Te + CuSO4 + 6H2OThe kinetics of this reaction were studied in a rotary drum reactor where a batch of the tellurium-rich ,solution was brought into contact with copper shot. The variable experimental conditions included temperature, acid concentration and per cent loading of the reactor with copper shot. To utilize the rate constants obtained from the batch reaction in designing a continuous flow reactor, a flow model of the latter was constructed. The mixing conditions were determined by pulse-input tracer tests.The results of the mixing study yielded the value of the dispersion coefficient due to eddy diffusion in the reactor. The method used for combining the chemical reaction and the mixing data in the design of a continuous-flow reactor is described. Resume Le tellure peut etre precipite des solutions de lixiviation des boues d' electroraffinage du cuivre ...

Histopathology of Mallards Dosed With Lead and Selected Substitute Shot

The histopathological response of male game farm mallards fed lead, three types of plastic-coated lead, two lead-magnesium alloys, iron, copper, zinc-coated iron, and molybdenum-coated iron shot was studied. Mallards fed lead, plastic-coated lead, or lead-magnesium alloy shot developed a similar pathological response, including the formation of acid-fast intranuclear inclusion bodies in the kidneys. Birds fed iron or molybdenum-coated iron shot developed hemosiderosis of the liver. Two of four mallards fed zinc-coated iron shot also developed hemosiderosis of the liver. No lesions were found in mallards fed copper shot.