TNT particle size distributions from detonated 155-mm howitzer rounds

To achieve sustainable range management and avoid or minimize environmental contamination, the Army needs to know the amount of explosives deposited on ranges from different munitions and how these are degraded and transported under different geological and climatic conditions. The physical form of the deposited explosives has a bearing on this problem, yet the shapes and size distributions of the explosive particles remaining after detonations are not known. We collected residues from 8 high-order and 6 low-order non-tactical detonations of TNT-filled 155-mm rounds. We found significant variation in the amount of TNT scattered from the high-order detonations, ranging from 0.00001 to 2% of the TNT in the original shell. All low-order detonations scattered percent-level amounts of TNT. We imaged thousands of TNT particles and determined the size, mass and surface-area distributions of particles collected from one high-order and one low-order detonation. For the high-order detonation, particles smaller than 1 mm contribute most of the mass and surface area of the TNT scattered. For the low-order detonation, most of the scattered TNT mass was in the form of un-heated, centimeter-sized pieces whereas most of the surface area was again from particles smaller than 1 mm. We also observed that the large pieces of TNT disintegrate readily, giving rise to many smaller particles that can quickly dissolve. We suggest picking up the large pieces of TNT before they disintegrate to become point sources of contamination.     

The effect of thermodynamic data on computer model predictions of uranium speciation in natural water systems

Computer models have found widespread application in order to help elucidate and predict changes in environmental systems. One such application is the prediction of trace metal speciation in aqueous systems. This is achieved by solving a set of non-linear equations involving equilibrium constants for all the components in the system, within mass and charge balance constraints. In this study a comparison of the predicted uranium speciation from two computer programs, WHAM and PHREEQCI, is used to illustrate the effect variations in thermodynamic data can have on the models produced. Using the original thermodynamic data provided with the models, WHAM predicted the UO2(2+) ion as the major species (84%) while PHREEQCI predicted UO2(HPO4)2(2-) as the major species (86%). Substituting uranium data from the Nuclear Energy Agency Thermochemical Database project (NEA-TDB) into both programs produced similar results from each program, with UO2F+ predicted to dominate (68%) in a groundwater sample. Natural water samples often contain humic substances. The possible interaction of such substances with uranium was also modelled. The WHAM program includes a discreet site electrostatic humic substance model, however in order to use the PHREEQCI program to model humic substance interactions, a 'model fulvic acid' dataset was added to the program. These models predicted 85 to 98% uranium-humic substance species at neutral pH. This indicates that humic substances do need to be taken into account when modelling uranium speciation in natural water samples.     

Uranium speciation in moorland river water samples: a comparison of experimental results and computer model predictions

An on-line method has been developed for separating inorganic and organic bound uranium species present in river water samples. The method utilised a small chelating resin (Hyphan) column incorporated into the sample introduction manifold of an ICP-MS instrument. The method was evaluated for samples from rivers on Dartmoor (Devon, UK), an area of granite overlain with peat bogs. The results indicate that organic-uranium species form a major proportion (80%) of the total dissolved uranium present. Further work with synthetic water samples indicated that the level of dissolved organic carbon played a greater role in determining the level of organic-uranium species than did sample pH. Computer models for the water samples were constructed using the WHAM program (incorporating uranium data from the Nuclear Energy Agency Thermochemical Database project) in order to predict the levels of organic-uranium species that would form. By varying the proportion of humic and fulvic acids used in the humic component, predictions within 10% of the experimental results were obtained. The program did exhibit a low bias at higher pH values (7.5) and low organic carbon concentrations (0.5 microg ml(-1)), but under the natural conditions prevalent in the Dartmoor water samples, the model predictions were successful.     

ISO 14001 registration: The process,the benefits,and the choice of registrar

This article introduces the concept of ISO 14001 registration, outlines related assessment processes, and reviews the drivers behind developing an ISO-14001-concordant environmental management system (EMS) and seeking third party registration of that EMS. It focuses on registration strategies for larger organizations and considerations in choosing a registrar, including: auditor qualifications, standards for the conduct of EMS audits, and some issues for audit and registration service providers. The authors conclude that it is beneficial to pursue an ISO-14001-concordant EMS and that the value of the system can be enhanced through registration. However, some thought should be given to choosing the appropriate registrar, in particular to their EMS and audit approaches and to the qualifications of their audit team. Service providers are also cautioned to remember that ISO 14001 is not the same as ISO 9000, and that the registrar's standard of care in the discharge of their work should reflect that. © 1998 John Wiley & Sons, Inc.     

Behavioural switching in a central place forager: patterns of diving behaviour in the macaroni penguin (Eudyptes chrysolophus)

Recording the activity of animals as they migrate or forage has proven hugely advantageous to understanding how animals use their environment. Where animals cannot be directly observed, the problem remains of how to identify distinct behaviours that represent an animal’s decision-making process. An excellent example of this problem is that of foraging penguins, which travel to sea to find prey to provision their young. Without direct sampling of the prey field, we cannot calibrate patterns of movement with prey capture, and therefore we cannot determine how different activities link to decision-making. To overcome this, we use a hidden markov model (HMM), which is a machine-learning technique that seeks to identify the underlying states of a system from observable outputs. We apply HMM to determine classes of behaviour from repetitive dives. We take dive data from 103 breeding macaroni penguins at Bird Island, South Georgia, for which we have measures of weight gain over a trip. We identify two classes of behaviour; those of short-shallow and long-deep dives. Using these two behaviours, we calculate the transition probabilities between these states and analyse these data to determine what predicts variation in the transition probabilities. We found that the stage of reproduction during a season, the sex and year of an individual influenced the probability of transition between long-deep and short-shallow sequential dives. We also found differences in the hourly transition rates between the four reproductive stages (incubation, broodguard, crèche and premoult) over a daily cycle. We conclude that this application of HMMs for behavioural switching is potentially useful for other species and other types of recorded behaviour.     

DEVELOPING CONFIDENCE IN CONCRETE REVETMENT PRODUCTS FOR BANK STABILIZATION1

ABSTRACT: There is a need to provide flood protection while maintaining stable bed and bank conditions in the riverine system, to stabilize earth embankment dams and spiliways, and to stabilize highway or railway embankments and levee systems. One approach to providing erosion protection and stabilization of channel banks, embankments and spill conveyances is with articulated concrete block systems. Numerous articulated concrete block systems are available for bank stabilization. However, prior to field installations few means are available to evaluate how well these block systems perform. To assist the designer in predicting site specific suitability, a series of hydraulic testing protocols have been developed to analyze block system performance. Two articulated block system testing protocols are presented to indicate how block hydraulic characteristics may be determined and provide performance assurance to both the designer and the owner.     

Effect of chemical amendments on remediation of potentially toxic trace elements (PTEs) and soil quality improvement in paddy fields

Remediation of potentially toxic trace elements (PTEs) in paddy fields is fundamental for crop safety. In situ application of chemical amendments has been widely adapted because of its cost-effectiveness and environmental safety. The main purpose of this research was to (1) evaluate the reduction in dissolved concentrations of cadmium (Cd) and arsenic (As) with the application of chemical amendments and (2) monitor microbial activity in the soil to determine the remediation efficiency. Three different chemical amendments, lime stone, steel slag, and acid mine drainage sludge, were applied to paddy fields, and rice (Oryza sativa L. Milyang 23) was cultivated. The application of chemical amendments immobilized both Cd and As in soil. Between the two PTEs, As reduction was significant (p < 0.05) with the addition of chemical amendments, whereas no significant reduction was observed for Cd than that for the control. Among six soil-related variables, PTE concentration showed a negative correlation with soil pH (r = ?0.70 for As and r = ?0.54 for Cd) and soil respiration (SR) (r = ?0.88 for As and r = ?0.45 for Cd). This result indicated that immobilization of PTEs in soil is dependent on soil pH and reduces PTE toxicity. Overall, the application of chemical amendments could be utilized for decreasing PTE (As and Cd) bioavailability and increasing microbial activity in the soil.     

Applying online fleet driver assessment to help identify,target and reduce occupational road safety risks

Many studies have shown that driver attitude and behaviour are important determinants of the likelihood of collision involvement. Knowledge of the Rules of the Road and the perception of hazards are also associated with collision involvement. The aim of this paper is to review the practical application of an online fleet driver assessment program to help identify, target and reduce occupational road safety risks. A large and unique data set collected from online assessment of drivers employed in a UK telecommunications organisation is analyzed. Data was also collected on driver demographics and their driving and collision history. Analysis of the data revealed that attitude, behaviour, knowledge and hazard perception are highly correlated with self-reported collisions. The influence of these variables on collision involvement was assessed using a Poisson regression model. Both attitude and behaviour scores exhibit a statistically significant association with collision involvement, along with other variables such as mileage driven, driver age and personality. The findings lend support to the need to create a safety culture in which driver assessment and improvement is the norm, as well as reducing exposure to risk wherever possible through better ways of working and travelling.     

Dechlorination comparison of mono-substituted PCBs with Mg/Pd in different solvent systems

It is widely recognized that polychlorinated biphenyls (PCBs) are a dangerous environmental pollutant. Even though the use and production of PCBs have been restricted, heavy industrial use has made them a wide-spread environmental issue today. Dehalogenation using zero-valent metals has been a promising avenue of research for the remediation of chlorinated compounds and other contaminants that are present in the environment. However, zero-valent metals by themselves have shown little capability of dechlorinating polychlorinated biphenyls (PCBs). Mechanically alloying the metal with a catalyst, such as palladium, creates a bimetallic system capable of dechlorinating PCBs very rapidly to biphenyl. This study primarily aims to evaluate the effects of solvent specificity on the kinetics of mono-substituted PCBs, in an attempt to determine the mechanism of degradation. Rate constants and final byproducts were determined for the contaminant systems in both water and methanol, and significant differences in the relative rates of reaction were observed between the two solvents.     

Investigating the capacity of an activated sludge process to reduce volatile organic compounds and odor emissions.

The effects of hydrogen sulfide (H2S) diffusion into activated sludge (AS) on odor and volatile organic compound (VOC) concentrations in offgas were studied over an 8-week period. Most VOCs detected in the offgas of both aeration tanks were aromatic hydrocarbons. The VOC concentrations generally decreased when H2S was introduced to the AS compared with the control, indicating a negative effect of H2S on VOC removal. Two volatile organic sulfur compounds present in the test AS offgas showed an increase followed by a decrease during H2S peak loads. Six VOCs and odor concentration increased during the introduction of an H2S peak; however no correlation was observed between H2S and odor concentration. The increase in odor concentration resulted from the increase in the concentration of six aromatic VOCs, which had their removal slowed down during a 100-ppmv H2S peak. Activated sludge diffusion provides effective H2S removal with minimal affect on odor emissions.