Daniel A. Steinhurst

Transient infrared spectroscopy of Mn2(CO)10 with 400 nm excitation

Abstract We report an ultrafast 400 nm pump–IR probe study of Mn 2 (CO) 10 photochemistry in cyclohexane and isopropanol at room temperature. While both Mn 2 (CO) 9 and Mn(CO) 5 are produced with UV dissociation, long wavelength excitation at 400 nm yields predominantly the monometal product, Mn(CO) 5 . The Mn(CO) 5 vibrational energy relaxation (VER) is analyzed in terms of the narrowing of its IR absorption band. The initial band broadening is attributed to population in low frequency vibrational modes (M–C stretches and bends) and the VER decay time is found to be on the 60 ps time scale in both solvents.

EMI Array for Cued UXO Discrimination

Abstract : A vehicle-towed array of time-domain electromagnetic sensors was designed and operated to optimize the classification of buried munitions from ancillary metallic debris and clutter. The array was designed to combine the data quality advantages of a gridded survey with the coverage efficiencies of a vehicular system. The design goal for this system was to collect data equal, if not better, in quality to the best gridded surveys while prosecuting many more targets each field day. In order to separate out the intrinsic target response properties from sensor/target geometry effects, the measured signature is inverted to estimate principal axis magnetic polarizabilities using a standard induced dipole response model. The technology was validated through two blind tests conducted at the Aberdeen Proving Ground Standardized UXO Test Site and as part of the ESTCP UXO Classification Study at the former Camp San Luis Obispo. The performance metrics used to monitor the success of the technology relate to production rate, accuracy of inverted features, analysis time, correct classification, and ease of use.

Identification of a Methane Oxidation Intermediate on Solid Oxide Fuel Cell Anode Surfaces with Fourier Transform Infrared Emission.

Fuel interactions on solid oxide fuel cell (SOFC) anodes are studied with in situ Fourier transform infrared emission spectroscopy (FTIRES). SOFCs are operated at 800 °C with CH4 as a representative hydrocarbon fuel. IR signatures of gas-phase oxidation products, CO2(g) and CO(g), are observed while cells are under load. A broad feature at 2295 cm(-1) is assigned to CO2 adsorbed on Ni as a CH4 oxidation intermediate during cell operation and while carbon deposits are electrochemically oxidized after CH4 operation. Electrochemical control provides confirmation of the assignment of adsorbed CO2. FTIRES has been demonstrated as a viable technique for the identification of fuel oxidation intermediates and products in working SOFCs, allowing for the elucidation of the mechanisms of fuel chemistry.

Ultrafast dissociation dynamics of ketones at 195 nm

Abstract The photodissociation dynamics of the 3s Rydberg state of three ketones (CH3CO–R, R=C2H5, C3H7, and iso-C4H9) and the ensuing dissociation of the nascent acetyl radical following 195 nm excitation were investigated by ultrafast photoionization spectroscopy. The 3s state the lifetimes of these ketones are similar (2.5–2.9 ps), though lifetimes of the acetyl radical range from 8.6 ps for CH3CO–C2H5, 15 ps for CH3CO–C3H7, to 23 ps for CH3CO–(iso-C4H9), which suggests that for larger R more vibrational degrees of freedom compete for the excess energy so that less energy is partitioned into the internal energy of the acetyl radical.

Multi-sensory, Data Fusion Detection System for Improved Situational Awareness

A multi-sensory approach is being used to develop new detection capabilities for improved damage assessment and real-time situational awareness. The detection system combines surveillance camera video images with selected spectral and acoustic signatures and image recognition technologies to provide a broad range of situational awareness. Various spectral and acoustic signatures, new video imaging techniques, and image recognition methods have been investigated and integrated into a multi-sensory prototype system. The prototype system is able to detect event signatures within the volume of a space (i.e., a “volume sensor”) rather than relying on spot-type fire detectors. Two prototype systems were built and assessed in full-scale testing aboard the exUSS Shadwell side-by-side with two commercial video image fire detection systems and several spot-type fire detection systems. Tests included a wide range of fire and nuisance sources, plus flooding and pipe rupture scenarios under actual shipboard background conditions. The prototype systems are shown to outperform the commercial fire detection systems for flaming and smoldering fires with a high level of nuisance immunity. In addition, they successfully detected the pipe ruptures and flooding scenarios. The system can be adapted for homeland security.

UXO and UXO Sensor Technology

Advanced electromagnetic induction sensors have been developed under the SERDP and ESTCP Munitions Response program to find and identify buried unexploded ordnance. These sensors consist of multiple transmit and receive coil configurations that collect sufficient data for inverting the time decaying, dipole polarizations of a buried metallic object. These polarizations can be used to identify the object as UXO or metallic debris. These sensor platforms have been deployed in both dynamic survey modes to locate and identify and stationary “cued” modes to just identify at target locations. ESTCP has sponsored a number of Live Site Demonstrations and these systems have been found to be very effective in finding UXO. An approach has been developed for advanced EMI survey data that applies a model based detection filter to locate metallic targets and a dipole inversion to identify the targets as UXO or clutter based on the inverted polarizations. Analysis of the Live Site data has found a significant fraction of the target locations have multiple target signals present. To address this, an N-dipole inversion is being applied to all target locations. This inversion inverts for a specified (N) number of targets. Fit results are returned for N = 1, 2, and 3 possible targets at each location. The problem arises that quite often all of the multi-target fits represent the data equally well. We will present these results and some strategies taken to insure that all possible targets of interest are selected from the multiple fit results. Work is also in progress to try and evaluate when the local target density is too high for valid analysis.

MULTISENSORY DETECTION SYSTEM FOR DAMAGE CONTROL AND SITUATIONAL AWARENESS

A data fusion-based, multisensory detection system, called “Volume Sensor”, was developed under the Advanced Damage Countermeasures (ADC) portion of the US Navys Future Naval Capabilities program (FNC) to meet reduced manning goals. A diverse group of sensing modalities was chosen to provide an automated damage control monitoring capability that could be constructed at a relatively low cost and also easily integrated into existing ship infrastructure. Volume Sensor employs an efficient, scalable, and adaptable design framework that can serve as a template for heterogeneous sensor network integration for situational awareness. In the development of Volume Sensor, a number of challenges were addressed and met with solutions that are applicable to heterogeneous sensor networks of any type. These solutions include: 1) a uniform, but general format for encapsulating sensor data, 2) a communications protocol for the transfer of sensor data and command and control of networked sensor systems, 3) the development of event specific data fusion algorithms, and 4) the design and implementation of modular and scalable system architecture. In full-scale testing on a shipboard environment, two prototype Volume Sensor systems demonstrated the capability to provide highly accurate and timely situational awareness regarding damage control events while simultaneously imparting a negligible footprint on the ships 100 Mbps Ethernet network and maintaining smooth and reliable operation in a real-time fashion.