Glass bead size and morphology characteristics in support of Crystal Mist field experiments

One of the tasks of the Lethality Group within US Army Space and Strategic Defense Command (USASSDC) is the development of a capability to simulate various missile intercept scenarios using computer codes. Currently under development within USASSDC and its various contractor organizations is a group of codes collected under a master code called PEGEM for Post Event Ground Effects Model. Among the various components of the code are modules which are used to predict atmospheric dispersion and transport of particles or droplets following release at the altitude specified in the missile intercept scenario. The atmospheric transport code takes into account various source term data from the intercept such as: initial cloud size; droplet or particle size distribution; and, total mass of agent released. An ongoing USASSDC experimental program termed Crystal Mist involved release of precision glass beads under various altitude and meteorological conditions to assist in validation and refinement of various codes that are components of PEGEM used to predict particle atmospheric transport and diffusion following a missile intercept. Here, soda-lime glass beads used in the Crystal Mist series of atmospheric transport and diffusion tests were characterized by scanning electron microscopy and automated image processing routines in order to fully define their size distributions and morphology. Four bead size classifications ranging from a median count diameter of 45 to 200 micrometers were found to be approximately spherical and to fall within the supplier`s sizing specifications. Log-normal functions fit to the measured size distributions resulted in geometric standard deviations ranging from 1.08 to 1.12, thereby fulfilling the field trial requirements for a relatively narrow bead size distribution

Winter season air pollution in El Paso-Ciudad Juarez. A review of air pollution studies in an international airshed

This report summarizes a number of research efforts completed over the past 20 years in the El Paso del Norte region to characterize pollution sources and air quality trends. The El Paso del Norte region encompasses the cities of El Paso, Texas and Ciudad Juarez, Chihuahua and is representative of many US-Mexico border communities that are facing important air quality issues as population growth and industrialization of Mexican border communities continue. Special attention is given to a group of studies carried out under special US Congressional funding and administered by the US Environmental Protection Agency. Many of these studies were fielded within the last several years to develop a better understanding of air pollution sources and trends in this typical border community. Summary findings from a wide range of studies dealing with such issues as the temporal and spatial distribution of pollutants and pollution potential from both stationary and mobile sources in both cities are presented. Particular emphasis is given to a recent study in El Paso-Ciudad Juarez that focussed on winter season PM{sub 10} pollution in El Paso-Ciudad Juarez. Preliminary estimates from this short-term study reveal that biomass combustion products and crustal material are significant components of winter season PM{sub 10} in this international border community

Field Analytical Technology Verification: The ETV Site Characterization Program

Innovative field characterization and monitoring technologies are often slow to be adopted by the environmental engineering/consulting community because of concerns that their performance has not been proven by an independent testing body, and/or they have not received the EPA`s blessing on a regional or national level. The purpose of the EPA Environmental Technology Verification (ETV) Site Characterization Pilot, a joint effort between EPA and DOE, is to accelerate the acceptance of technologies that reduce the cost and increase the speed of environmental clean-up and monitoring. Technology verifications that have been completed or are underway include: in situ technologies for the characterization of sub-surface hydrocarbon plumes, field-portable GC/MS systems, field-portable X-ray fluorescence analyzers, soil sampling technologies, field-portable PCB analyzers, analyzers for VOC analysis at the wellhead, and decision support software systems to aid site sample collection and contaminant plume definition. The verification process follows a somewhat generic pathway. A user-community need is identified, the vendor community is canvassed, and relevant, interested companies are selected. A demonstration plan is prepared by the verification organization and circulated to participants prior to the field activities. Field trials are normally held at two geologically or environmentally different sites and typically require one week at each site. Samples (soil, soil gas, water, surface wipe etc.) provided to the vendor at the demonstration include site-specific samples and standards or performance evaluation samples. Sample splits are sent to a pre-selected laboratory for analysis using a reference method. Laboratory data are used for comparison with field technology results during the data analysis phase of the demonstration

Development of parent- and teacher-reported emotional and behavioural problems in young people with intellectual disabilities: Does level of ID matter?

This study described similarities and differences in the 5-year stability and change of problem behaviour between youths attending schools for children with mild to borderline (MiID) versus moderate intellectual disabilities (MoID). A two-wave multiple-birth-cohort sample of 6 to 18-year-old was assessed twice across a 5-year interval using the Developmental Behaviour Checklist Primary Carer version (n = 718) and Teacher version (n = 313). For most types of problem behaviour youths with MiID and MoID showed similar levels of stability of individual differences, persistence and onset of psychopathology. Whenever differences were found, youths with MoID showed the highest level of stability, persistence and onset across informants. Mean levels of parent-reported, but not teacher-reported, problem behaviour, regardless of level of intellectual disability, decreased during the 5-year follow-up period. Youths with MoID and MiID are at risk for persistent psychopathology to a similar degree. Different informants showed to have a different evaluation of the level and the amount of change of problem behaviour, and should be considered complementary in the diagnostic process. © 2007 BILD Publications

What smells? Developing in-field methods to characterize the chemical composition of wild mammalian scent cues

Olfactory cues play an important role in mammalian biology, but have been challenging to assess in the field. Current methods pose problematic issues with sample storage and transportation, limiting our ability to connect chemical variation in scents with relevant ecological and behavioral contexts. Real-time, in-field analysis via portable gas chromatography–mass spectrometry (GC-MS) has the potential to overcome these issues, but with trade-offs of reduced sensitivity and compound mass range. We field-tested the ability of portable GC-MS to support two representative applications of chemical ecology research with a wild arboreal primate, common marmoset monkeys (Callithrix jacchus). We developed methods to (a) evaluate the chemical composition of marmoset scent marks deposited at feeding sites and (b) characterize the scent profiles of exudates eaten by marmosets. We successfully collected marmoset scent marks across several canopy heights, with the portable GC-MS detecting known components of marmoset glandular secretions and differentiating these from in-field controls. Likewise, variation in the chemical profile of scent marks demonstrated a significant correlation with marmoset feeding behavior, indicating these scents’ biological relevance. The portable GC-MS also delineated species-specific olfactory signatures of exudates fed on by marmosets. Despite the trade-offs, portable GC-MS represents a viable option for characterizing olfactory compounds used by wild mammals, yielding biologically relevant data. While the decision to adopt portable GC-MS will likely depend on site- and project-specific needs, our ability to conduct two example applications under relatively challenging field conditions bodes well for the versatility of in-field GC-MS

Sensor Acquisition for Water Utilities: Survey, Down Selection Process, and Technology List

The early detection of the biological and chemical contamination of water distribution systems is a necessary capability for securing the nation's water supply. Current and emerging early-detection technology capabilities and shortcomings need to be identified and assessed to provide government agencies and water utilities with an improved methodology for assessing the value of installing these technologies. The Department of Homeland Security (DHS) has tasked a multi-laboratory team to evaluate current and future needs to protect the nation's water distribution infrastructure by supporting an objective evaluation of current and new technologies. The LLNL deliverable from this Operational Technology Demonstration (OTD) was to assist the development of a technology acquisition process for a water distribution early warning system. The technology survey includes a review of previous sensor surveys and current test programs and a compiled database of relevant technologies. In the survey paper we discuss previous efforts by governmental agencies, research organizations, and private companies. We provide a survey of previous sensor studies with regard to the use of Early Warning Systems (EWS) that includes earlier surveys, testing programs, and response studies. The list of sensor technologies was ultimately developed to assist in the recommendation of candidate technologies for laboratory and field testing. A set of recommendations for future sensor selection efforts has been appended to this document, as has a down selection example for a hypothetical water utility

Psychometric properties of the revised Developmental Behaviour Checklist scales in Dutch children with intellectual disability

The present study assessed the reliability and validity of the revised scales of the Developmental Behaviour Checklist (DBC) in a Dutch sample of children with intellectual disability (ID). The psychometric properties of the parent and teacher versions of the DBC were assessed in various subsamples derived from a sample of 1057 Dutch children (age range = 6-18 years) with ID or borderline intellectual functioning. Good test-retest reliability was shown both for the parent and teacher versions. Moderate inter-parent agreement and high one-year stability was found for the scale scores. Construct validity was satisfactory, although limited by high informant variance. The DBC scales showed good criterion-related validity, as indicated by significant mean differences between referred and non-referred children, and between children with and without a corresponding DSM-IV diagnosis. The reliability and validity of the revised DBC scales are satisfactory, and the checklist is recommended for clinical and research purposes