Kurt L. Silvers

Redox-Active Metal–Organic Composites for Highly Selective Oxygen Separation Applications

A redox-active metal-organic composite material shows improved and selective O2 adsorption over N2 with respect to individual components (MIL-101 and ferrocene). The O2 sensitivity of the composite material arises due to the formation of maghemite nanoparticles with the pore of the metal-organic framework material.

Experimental Analysis of a Piezoelectric Energy Harvesting System for Harmonic, Random, and Sine on Random Vibration

Harvesting power with a piezoelectric vibration powered generator using a full-wave rectifier conditioning circuit is experimentally compared for varying sinusoidal, random, and sine on random (SOR) input vibration scenarios; the implications of source vibration characteristics on harvester design are discussed. The rise in popularity of harvesting energy from ambient vibrations has made compact, energy dense piezoelectric generators commercially available. Much of the available literature focuses on maximizing harvested power through nonlinear processing circuits that require accurate knowledge of generator internal mechanical and electrical characteristics and idealization of the input vibration source, which cannot be assumed in general application. Variations in source vibration and load resistance are explored for a commercially available piezoelectric generator. The results agree with numerical and theoretical predictions in the previous literature for optimal power harvesting in sinusoidal and flat broadband vibration scenarios. Going beyond idealized steady-state sinusoidal and flat random vibration input, experimental SOR testing allows for more accurate representation of real world ambient vibration. It is shown that characteristic interactions from more complex vibration sources significantly alter power generation and processing requirements by varying harvested power, shifting optimal conditioning impedance, inducing voltage fluctuations, and ultimately rendering idealized sinusoidal and random analyses incorrect.

Validation Testing of the Nitric Acid Dissolution Step Within the K Basin Sludge Pretreatment Process

The work described in this report involved comprehensive bench-scale testing of nitric acid (HNO{sub 3}) dissolution of actual sludge materials from the Hanford K East (KE) Basin to confirm the baseline chemical pretreatment process. In addition, process monitoring and material balance information was collected to support the development and refinement of process flow diagrams. The testing was performed by Pacific Northwest National Laboratory (PNNL)for the US Department of Energys Office of Spent Fuel Stabilization (EM-67) and Numatec Hanford Corporation (NHC) to assist in the development of the K Basin Sludge Pretreatment Process. The baseline chemical pretreatment process for K Basin sludge is nitric acid dissolution of all particulate material passing a 1/4-in. screen. The acid-insoluble fraction (residual solids) will be stabilized (possibly by chemical leaching/rinsing and grouting), packaged, and transferred to the Hanford Environmental Restoration Disposal Facility (ERDF). The liquid fraction is to be diluted with depleted uranium for uranium criticality safety and iron nitrate for plutonium criticality safety, and neutralized with sodium hydroxide. The liquid fraction and associated precipitates are to be stored in the Hanford Tank Waste Remediation Systems (TWRS) pending vitrification. It is expected that most of the polychlorinated biphenyls (PCBs), associated with some K Basin sludges, will remain with the residual solids for ultimate disposal to ERDF. Filtration and precipitation during the neutralization step will further remove trace quantities of PCBs within the liquid fraction. The purpose of the work discussed in this report was to examine the dissolution behavior of actual KE Basin sludge materials at baseline flowsheet conditions and validate the.dissolution process step through bench-scale testing. The progress of the dissolution was evaluated by measuring the solution electrical conductivity and concentrations of key species in the dissolver solutions as a function of reaction (dissolution) time, by analyzing offgas generation rate and composition, and by analyzing intermittent and final acid-insoluble solids at the end of the dissolution. The testing was conducted in a system designed to assess parameters that can influence sludge dissolution and provide information that can be used to determine operating conditions for the actual system.

Missile captive carry monitoring and helicopter identification using a capacitive microelectromechanical systems accelerometer

Military missiles are exposed to many sources of mechanical vibration that can affect system reliability, safety, and mission effectiveness. The US Army Aviation and Missile Research Development and Engineering Center has been developing missile health monitoring systems to assess and improve reliability, reduce life cycle costs, and increase system readiness. One of the most significant exposures to vibration occurs when the missile is being carried by a helicopter or other aviation platform, which is a condition known as captive carry. Recording the duration of captive carry exposure during the missile’s service life can enable the implementation of predictive maintenance and resource management programs. Since the vibration imparted by each class of helicopter varies in frequency and amplitude, tracking the vibration exposure from each helicopter separately can help quantify the severity and harmonic content of the exposure. To help address these needs, the authors have developed a captive carry health monitor for the Hellfire II missile. The captive carry health monitor is an embedded usage monitoring device installed on the outer skin of the Hellfire II missile to record the cumulative hours the host missile has been in captive carry mode. To classify the vibration by class of helicopter, the captive carry health monitor analyzes the amplitude and frequency content of the vibration with the Goertzel algorithm to detect the presence of distinctive rotor harmonics. This article provides an overview of the captive carry health monitor, presents vibration data collected on missiles during captive carry, describes data analysis techniques used to monitor captive carry and identify the class of helicopter, and discusses the potential application of missile health and usage data for real-time reliability analysis. More broadly, this article illuminates the challenges of developing a structural health monitor to classify transportation modes in an unstructured environment.

NOA: A Scalable Multi-Parent Clustering Hierarchy for WSNs

Abstract NOA is a multi-hop, multi-parent, N-tiered, hierarchical clustering algorithm that provides a scalable, robust and reliable solution for autonomous configuration of large-scale wireless sensor networks. The novel clustering hierarchys inherent benefits can be utilized by in-network data processing techniques to provide a robust data processing solution capable of reducing the amount of data sent to data sinks. Utilizing a multi-parent framework, NOA reduces the cost of network configuration when compared to current hierarchical beaconing solutions by removing the r-hop fi (where r is the radius of the cluster). NOA instead utilizes common children to distribute information about the hierarchys topology to siblings. NOA2, a two-parent clustering hierarchy solution, and NOA3, the three-parent variant, saw up to an 83% and 72% reduction in communication overhead, respectively, when compared to configuring the network using a one-parent hierarchical beaconing solution, as well as 92% and 88% less overhead when compared to two-and three-parent variants of hierarchical beaconing.

Implementation of an electronic media security system

Recent security lapses within the Department of Energy Laboratories prompted the establishment and implementation of additional procedures and training for operations involving classified removable electronic media (CREM) storage. In addition, the definition of CREM has been expanded and the number of CREM has increased significantly. Procedures now require that all CREM be inventoried and accounted for on a weekly basis. Weekly inventories consist of a physical comparison of each item against the reportable inventory listing. Securing and accounting for CREM is a continuous challenge for existing security systems. To address the challenge, Pacific Northwest National Laboratory (PNNL) has developed an automated electronic media security system (EMSS) for a weekly CREM inventory collection and reporting system. The EMSS approach is to tag the CREM with an electronically readable unique identification code and automatically collect data on the inventory in each security container or vault at a user-defined interval and upon detection of an access event, thus eliminating the need for hand-written inventory sheets while allowing automated transfer of the collected inventory data to an electronic reporting system. An electronic log of CREM access events is maintained, providing enhanced accountability for daily/weekly checks, routine audits, and follow-up investigations. The key attributes of the EMSS include improved accountability, reduced risk of human error, improved accuracy and timeliness of inventory data, and reduced costs as a result of man-hour reductions.

Missile captive carry monitoring using a capacitive MEMS accelerometer

Military missiles are exposed to many sources of mechanical vibration that can affect system reliability, safety, and mission effectiveness. One of the most significant exposures to vibration occurs when the missile is being carried by an aviation platform, which is a condition known as captive carry. If the duration of captive carry exposure could be recorded during the missiles service life, several advantages could be realized. Missiles that have been exposed to durations outside the design envelop could be flagged or screened for maintenance or inspection; lightly exposed missiles could be selected for critical mission applications; and missile allocation to missions could be based on prior use to avoid overuse. The U. S. Army Aviation and Missile Research Development and Engineering Center (AMRDEC) has been developing health monitoring systems to assess and improve reliability of missiles during storage and field exposures. Under the direction of AMRDEC staff, engineers at the Pacific Northwest National Laboratory have developed a Captive Carry Health Monitor (CCHM) for the HELLFIRE II missile. The CCHM is an embedded usage monitoring device installed on the outer skin of the HELLFIRE II missile to record the cumulative hours the host missile has been in captive carry mode and thereby assess the overall health of the missile. This paper provides an overview of the CCHM electrical and package design, describes field testing and data analysis techniques used to identify captive carry, and discusses the potential application of missile health and usage data for real-time reliability analysis and fleet management.

Health Monitoring: Asset Damage Detection

The Health Monitor System (HMS) is a low-cost, low-power, battery-powered device capable of measuring temperature, humidity, and shock. Many mission-critical items are susceptible to shock damage. To help prevent shock damage, assets often are placed in robust custom containers with shock damping and absorption devices. Assets are still at risk of damage while in their protective containers. Having a Health Monitor attached to an asset or container allows the status of the asset to be determined. The Health Monitor can measure, record, store, analyze, and display to the user if a shock event has occurred that puts the asset at risk of failure. Extensive shock testing and algorithm implementation were required to develop a Health Monitor that uses a single-point 3-axis accelerometer to determine the type, height, and severity of a shock event.

Active sensor tags for global visibility of asset readiness

The era of wireless communication and discrete, autonomous sensors platforms is upon us. Advances in radio-frequency (RF) technology from simple two-way personal communications to smart, independent, sensor command, and control units has greatly expanded the applications domain. In the past four years, Pacific Northwest National Laboratory (PNNL) scientists and engineers have developed smart sensor tags (health tags) for the Army to monitor environmental conditions of high value assets over their lifetime (10 yrs). These field tested health tags uniquely identify individual assets, record and store data, run diagnostic and prognostic protocols, identify asset performance status (GO, CAUTION, NO-GO), and provide all this information over a wireless RF link to a portable, hand held reader. Leveraging the innovation achieved for health monitoring tags, the next generation active sensor tag has been developed (FlexiTag) providing reduced tag size and manufacturing cost, greater sensor interface capabilities, and a flexible substrate for surface mount conformity. The design has a greatly reduced part count due to the use of newly available, highly integrated RF chip sets. In addition to asset health monitoring, the new tag platform opens up additional application areas such as TTL (tagging, tracking, and locating), real-time machine fault monitoring, and ad-hoc sensor networking. This paper will compare and contrast the FlexiTag to its predecessors and discuss the current application areas it is being applied to.

CREM monitoring: a wireless RF application

Recent security lapses within the Department of Energy laboratories prompted the establishment and implementation of additional procedures and training for operations involving classified removable electronic media (CREM) storage. In addition, the definition of CREM has been expanded and the number of CREM has increased significantly. Procedures now require that all CREM be inventoried and accounted for on a weekly basis. Weekly inventories consist of a physical comparison of each item against the reportable inventory listing. Securing and accounting for CREM is a continuous challenge for existing security systems. To address this challenge, an innovative framework, encompassing a suite of technologies, has been developed by Pacific Northwest National Laboratory (PNNL) to monitor, track, and locate CREM in safes, vaults, and storage areas. This Automated Removable Media Observation and Reporting (ARMOR)framework, described in this paper, is an extension of an existing PNNL program, SecureSafe. The key attributes of systems built around the ARMOR framework include improved accountability, reduced risk of human error, improved accuracy and timeliness of inventory data, and reduced costs. ARMOR solutions require each CREM to be tagged with a unique electronically readable ID code. Inventory data is collected from tagged CREM at regular intervals and upon detection of an access event. Automated inventory collection and report generation eliminates the need for hand-written inventory sheets and allows electronic transfer of the collected inventory data to a modern electronic reporting system. An electronic log of CREM access events is maintained, providing enhanced accountability for daily/weekly checks, routine audits, and follow-up investigations.