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Wilmsmeyer A.R.,Virginia Polytechnic Institute and State University | Gordon W.O.,U.S. Army | Davis E.D.,OptiMetrics, Inc. | Mantooth B.A.,U.S. Army | And 2 more authors.
Review of Scientific Instruments | Year: 2014

A fundamental understanding of the surface chemistry of chemical warfare agents is needed to fully predict the interaction of these toxic molecules with militarily relevant materials, catalysts, and environmental surfaces. For example, rules for predicting the surface chemistry of agents can be applied to the creation of next generation decontaminants, reactive coatings, and protective materials for the warfighter. Here, we describe a multifunctional ultra-high vacuum instrument for conducting comprehensive studies of the adsorption, desorption, and surface chemistry of chemical warfare agents on model and militarily relevant surfaces. The system applies reflection-absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and mass spectrometry to study adsorption and surface reactions of chemical warfare agents. Several novel components have been developed to address the unique safety and sample exposure challenges that accompany the research of these toxic, often very low vapor pressure, compounds. While results of vacuum-based surface science techniques may not necessarily translate directly to environmental processes, learning about the fundamental chemistry will begin to inform scientists about the critical aspects that impact real-world applications. © 2014 AIP Publishing LLC.


Cooley K.A.,OptiMetrics, Inc. | Pearl T.P.,OptiMetrics, Inc. | Varady M.J.,OptiMetrics, Inc. | Mantooth B.A.,U.S. Army | Willis M.P.,U.S. Army
ACS Applied Materials and Interfaces | Year: 2014

Chemical warfare agents (CWA) can be absorbed by variety of materials including polymeric coatings like paints through bulk liquid contact, thus presenting touch and vapor hazards to interacting personnel. In order for accurate hazard assessments and subsequent decontamination approaches to be designed, it is necessary to characterize the absorption and distribution of highly toxic species, as well as their chemical simulant analogs, in the subsurface of engineered, heterogeneous materials. Using a combination of judicious sample preparation in concert with scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), it should be possible to directly measure the uptake and distribution of CWA simulants in the subsurface of complex multilayer coatings. Polyurethane and alkyd coatings were applied to aluminum and silicon substrates and contaminated with 2-chloroethyl ethyl sulfide (CEES) and dimethyl methylphosphonate (DMMP). The surfaces and cross-sectional interfaces of the contaminated coatings were probed with SEM-EDS to provide imaging, spectral, and elemental mapping data of the contaminant-material systems. This work demonstrated SEM-EDS capability to detect and spatially resolve unique elemental signatures of CWA simulants within military coatings. The visual and quantitative results provided by these direct measurements illustrate contaminant spatial distributions, provide order-ofmagnitude approximations for diffusion coefficients, and reveal material characteristics that may impact contaminant transport into complex coating materials. It was found that contaminant uptake was significantly different between the topcoat and primer layers. © 2014 American Chemical Society.


Varady M.J.,OptiMetrics, Inc. | Pearl T.P.,OptiMetrics, Inc. | Stevenson S.M.,U.S. Army | Mantooth B.A.,U.S. Army
Industrial and Engineering Chemistry Research | Year: 2016

A continuum model of the transport and reaction processes occurring during decontamination of the chemical warfare agent (CWA) [2-(diisopropylamino)ethyl]-O-ethyl methylphosphonothioate (VX) absorbed in a silicone elastomer using solutions of sodium hydroxide in water, methanol, and mixtures thereof is presented. This model is based on the Maxwell-Stefan formulation of multicomponent diffusion along with the Flory-Huggins model of thermodynamic equilibrium in the polymer. It was found that, as methanol from the decontaminant absorbs into the silicone, the diffusivity of VX increases, accelerating its flux from the polymer phase to the decontaminant liquid phase. This composition dependence of the diffusivity was accurately described by the Vignes equation. Although the decontamination kinetics were slower for the methanol-based decontaminant in a well-stirred liquid-phase reactor, the overall performance was superior compared to the aqueous-based decontaminant due to the enhanced extraction rate from the polymer. These findings highlight the need to consider extraction dynamics on equal footing with reaction kinetics when formulating decontaminants intended for use on absorbing polymer materials. © 2016 American Chemical Society.


Willis M.P.,U.S. Army | Varady M.J.,OptiMetrics, Inc. | Pearl T.P.,OptiMetrics, Inc. | Fouse J.C.,SAIC | And 3 more authors.
Journal of Hazardous Materials | Year: 2013

Chemical warfare agent simulants are often used as an agent surrogate to perform environmental testing, mitigating exposure hazards. This work specifically addresses the assessment of downwind agent vapor concentration resulting from an evaporating simulant droplet. A previously developed methodology was used to estimate the mass diffusivities of the chemical warfare agent simulants methyl salicylate, 2-chloroethyl ethyl sulfide, di-ethyl malonate, and chloroethyl phenyl sulfide. Along with the diffusivity of the chemical warfare agent bis(2-chloroethyl) sulfide, the simulant diffusivities were used in an advection-diffusion model to predict the vapor concentrations downwind from an evaporating droplet of each chemical at various wind velocities and temperatures. The results demonstrate that the simulant-to-agent concentration ratio and the corresponding vapor pressure ratio are equivalent under certain conditions. Specifically, the relationship is valid within ranges of measurement locations relative to the evaporating droplet and observation times. The valid ranges depend on the relative transport properties of the agent and simulant, and whether vapor transport is diffusion or advection dominant. © 2013.


PubMed | United States Medical Research Institute of Infectious Diseases, TMG Biosciences LLC, OptiMetrics, Inc., Edgewood Chemical and Biological Center and 2 more.
Type: | Journal: BMC bioinformatics | Year: 2015

The detection of pathogens in complex sample backgrounds has been revolutionized by wide access to next-generation sequencing (NGS) platforms. However, analytical methods to support NGS platforms are not as uniformly available. Pathosphere (found at Pathosphere.org) is a cloud - based open - sourced community tool that allowsfor communication, collaboration and sharing of NGS analytical tools and data amongst scientists working in academia, industry and government. The architecture allows for users to upload data and run available bioinformatics pipelines without the need for onsite processing hardware or technical support.The pathogen detection capabilities hosted on Pathosphere were tested by analyzing pathogen-containing samples sequenced by NGS with both spiked human samples as well as human and zoonotic host backgrounds. Pathosphere analytical pipelines developed by Edgewood Chemical Biological Center (ECBC) identified spiked pathogens within a common sample analyzed by 454, Ion Torrent, and Illumina sequencing platforms. ECBC pipelines also correctly identified pathogens in human samples containing arenavirus in addition to animal samples containing flavivirus and coronavirus. These analytical methods were limited in the detection of sequences with limited homology to previous annotations within NCBI databases, such as parvovirus. Utilizing the pipeline-hosting adaptability of Pathosphere, the analytical suite was supplemented by analytical pipelines designed by the United States Army Medical Research Insititute of Infectious Diseases and Walter Reed Army Institute of Research (USAMRIID-WRAIR). These pipelines were implemented and detected parvovirus sequence in the sample that the ECBC iterative analysis previously failed to identify.By accurately detecting pathogens in a variety of samples, this work demonstrates the utility of Pathosphere and provides a platform for utilizing, modifying and creating pipelines for a variety of NGS technologies developed to detect pathogens in complex sample backgrounds. These results serve as an exhibition for the existing pipelines and web-based interface of Pathosphere as well as the plug-in adaptability that allows for integration of newer NGS analytical software as it becomes available.


Jordan S.,U.S. Air force | Armstrong E.,OptiMetrics, Inc. | Larsson H.,Swedish Defence Research Agency | Gebhardt M.,U.S. Air force | Steinvall O.,Swedish Defence Research Agency
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

In many laser radar systems the intensity value's strength is dependent on the reflectivity of the measured surface. High intensity values are necessary for accurate range measurements. When measuring a low-reflectivity surface the returning laser intensity will be low. This, in turn, results in high uncertainty in the range estimate. In this paper, an approach to correct the intensity values are presented which results in more accurate range estimates even on low-reflecting surfaces. Examples are shown using the ASC (Advanced Scientific Concepts) FLASH 3D LADAR sensor. During a data collection several series of measurements characterizing the shape of the return laser pulse from surfaces with known reflectivity were performed. Using principal components analysis (PCA), variation in pulse shape as a function of laser intensity was determined. These data were then used to identify a parametric model that described the variation in intensity values relative to the surface's reflectivity. Based on the model, an approach to systematically adjust intensity values has been developed. In this paper we will also examine laser timing jitter, intensity, and their effects on range estimation. © 2010 SPIE.


Wilmsmeyer A.R.,Virginia Polytechnic Institute and State University | Gordon W.O.,Research and Technology Directorate | Davis E.D.,OptiMetrics, Inc. | Troya D.,Virginia Polytechnic Institute and State University | And 3 more authors.
Journal of Physical Chemistry C | Year: 2013

The fundamental interactions of a series of chemical warfare agent (CWA) simulants on amorphous silica particulates have been investigated with transmission infrared spectroscopy and temperature-programmed desorption (TPD). The simulants methyl dichlorophosphate (MDCP), dimethyl cholorophosphate (DMCP), trimethyl phosphate (TMP), dimethyl methylphosphonate (DMMP), and diisopropyl methylphosphonate (DIMP) were chosen to help develop a comprehensive understanding for how the structure and functionality of CWA surrogate compounds affect uptake and hydrogen-bond strengths at the gas-surface interface. Each simulant was found to adsorb molecularly to silica through the formation of strong hydrogen bonds primarily between isolated surface silanol groups and the oxygen atom of the P=O moiety in the adsorbate. The TPD data revealed that the activation energy for desorption of a single simulant molecule from amorphous silica varied slightly with coverage. In the limit of zero coverage and the absence of significant surface defects, the activation energies for desorption were found to follow the trend MDCP < DMCP < TMP < DMMP < DIMP. This trend demonstrates the critical role of electron-withdrawing substituents in determining the adsorption energies through hydrogen-bonding interactions. The infrared spectra for each adsorbed species, recorded during uptake, showed a significant shift in the frequency of the ν(SiO-H) mode as the hydrogen bonds formed. A clear linear relationship between the desorption energy and the shift of the surface ν(SiO-H) mode across this series of adsorbates demonstrates that the Badger-Bauer relationship, established origninally for solute-solvent interactions, effectively extends to gas-surface interactions. High-level electronic structure calculations, including extrapolation to the complete basis set limit, reproduce the experimental energies of all simulants with high levels of accuracy and have been employed to provide insight into the molecular-level details of adsorption geometries for the simulants and to predict the interaction energies for the CWA isopropyl methylphosphonofluoridate (sarin). © 2013 American Chemical Society.


PubMed | OptiMetrics, Inc., Leidos Inc., Research & Technology Directorate and Virginia Polytechnic Institute and State University
Type: Journal Article | Journal: Applied and environmental microbiology | Year: 2016

Effective microbial forensic analysis of materials used in a potential biological attack requires robust methods of morphological and genetic characterization of the attack materials in order to enable the attribution of the materials to potential sources and to exclude other potential sources. The genetic homogeneity and potential intersample variability of many of the category A to C bioterrorism agents offer a particular challenge to the generation of attributive signatures, potentially requiring whole-genome or proteomic approaches to be utilized. Currently, irradiation of mail is standard practice at several government facilities judged to be at particularly high risk. Thus, initial forensic signatures would need to be recovered from inactivated (nonviable) material. In the study described in this report, we determined the effects of high-dose gamma irradiation on forensic markers of bacterial biothreat agent surrogate organisms with a particular emphasis on the suitability of genomic DNA (gDNA) recovered from such sources as a template for whole-genome analysis. While irradiation of spores and vegetative cells affected the retention of Gram and spore stains and sheared gDNA into small fragments, we found that irradiated material could be utilized to generate accurate whole-genome sequence data on the Illumina and Roche 454 sequencing platforms.


Patent
OptiMetrics, Inc. | Date: 2011-06-10

An estimate of random error in an eye-tracking system is done directly from eye-tracker outputs during a trial, without the need for an explicit calibration process. The distances traveled between adjacent user observations are computed, and the random error _(r )of the eye-tracker system is estimated using the statistical distribution of the computed distances. In the preferred embodiment, the distances traveled between adjacent observations is sampled on a continuous basis. The process includes measuring the mode (peak value) of the distribution in observation distances. These values are sorted by increasing distance, and a window of about 50 observations is used to estimate the mode of the distance distribution. A running estimate of the mode is computed, and the result is divided by a constant. A preferred constant of 1.61 was derived using a series of Monte Carlo simulations.


Grant
Agency: Department of Defense | Branch: Navy | Program: SBIR | Phase: Phase II | Award Amount: 686.43K | Year: 2010

This proposal addresses the development a Multi-Sensor Based Super-Resolution Imaging LADAR System. A main application of this system is to aid rotary wing pilots in visually degraded environment landings; however, other applications include improved situational awareness in many conditions, collision warning, targeting and terrain mapping. For purposes of this proposal, we will refer to it as the “Multi-Sensor LADAR”.

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