New SMART approaches to fast, high sensitivity, high selectivity, low false indication, self communicating, distributed sensor networks for detection of chemical, biological and radiation threats are being developed at PNNL. These new sensors have their roots in clever combinations of high affinity ligands, self assembled monolayers, shape-specific receptor surfaces, mesoporous superstructures, rapidly fabricated single-chain antibodies, stabilized enzyme reactors and manipulated micro-beads for optical, mass, and direct electronic transduction. Assemblies of these SMART materials and structures are able to efficiently reject the bulk of highly cluttered physical environmental backgrounds, collect the product of interest with extremely high selectivity, concentrate it and present it for efficient and sensitive detection. The general construction methodology for these structures and examples of new sensor systems for detecting chemical, biological and nuclear materials of concern in the Homeland Security context is presented.

The detection of fissile materials is of great interest to the National Homeland Security effort. Significant advantages of a technique using nuclear acoustic resonance (NAR) over the traditional detection methods are that it will not rely on nuclear radiation signatures, will be non-intrusive, and has the potential to identify individual components of composite substances including fractional isotope composition of the material under investigation. Technique uses the unique nuclear acoustic resonance signatures generated when materials are driven by high intensity resonant acoustic waves in the presence of a constant magnetic field. This would cause shifts in the nuclear and electronic spin energy levels of the material. Nuclear energy level shifts induce changes in the unique nuclear magnetic properties of the material which can then be quantified using sensitive instruments. This paper will discuss in detail, the physics and detection principles of NAR and also provide some preliminary results.

Lawrence Livermore National Laboratory (LLNL) recently conducted a field-test of radiation detection and identification equipment at the air cargo facility of Federal Express (FedEx) located at Denver International Airport (DIA) over a period of two weeks. Comprehensive background measurements were performed and were analyzed, and a trial strategy for detection and identification of parcels displaying radioactivity was implemented to aid in future development of a comprehensive protection plan. The purpose of this project was threefold: quantify background radiation environments at an air cargo facility; quantify and identify "nuisance" alarms; evaluate the performance of various isotope identifiers deployed in an operational environment. LLNL emplaced a primary screening detector that provided the initial detection of radiation anomalies in near real-time. Once detected, a secondary test location provided capability to perform higher-resolution analysis of the parcels or containers that triggered the primary detector. Two triggered radiation events were observed during the course of this project. Both of the radiation events were determined to be legitimate shipments of radioactive material. The overall effect of this project on FedEx operations and personnel was deemed to be minimal.

The inspection of sealed containers is a critical task for personnel charged with enforcing government policies, maintaining public safety, and ensuring national security. The Pacific Northwest National Laboratory (PNNL) has developed a portable, handheld acoustic inspection device (AID) that provides non-invasive container interrogation and material identification capabilities. The AID technology has been deployed worldwide and user’s are providing feedback and requesting additional capabilities and functionality. Recently, PNNL has developed a laboratory-based system for automated, ultrasonic characterization of fluids to support database development for the AID. Using pulse-echo ultrasound, ultrasonic pulses are launched into a container or bulk-solid commodity. The return echoes from these pulses are analyzed in terms of time-of-flight and frequency content (as a function of temperature) to extract physical property measurements (acoustic velocity and attenuation) of the material under test. These measured values are then compared to a tailored database of materials and fluids property data acquired using the Velocity-Attenuation Measurement System (VAMS). This bench-top platform acquires key ultrasonic property measurements as a function of temperature and frequency. This paper describes the technical basis for operation of the VAMS, recent enhancements to the measurement algorithms for both the VAMS and AID technologies, and new measurement data from laboratory testing and performance demonstration activities. Applications for homeland security and counterterrorism, law enforcement, drug-interdiction and fuel transportation compliance activities will be discussed.

Use of microwave for investigating the integrity of structural elements has been established as a nondestructive evaluation (NDE) method in civil engineering, especially for detection of invisible damage such as voids and cracks inside concrete and debonding between rebars and concrete caused by corrosions and earthquakes, and objects such as steel rebars or dowels. The authors have found that focused microwaves are much more effective than unfocused ones and thus developed two systems for focusing microwaves: one using dielectric lenses and the other using antenna arrays. The former is referred to as a passive system as the focusing point has to be manually adjusted by moving the lenses, while the latter is an active system as focusing is automatically performed by software without moving the antenna arrays. This paper presents the numerical and experimental results, including measurement of dielectric properties of related materials, the passive microwave imaging technology using dielectric lenses, and the active microwave imaging technology using the antenna arrays with 3-dimensional image reconstruction algorithms. In addition, this paper presents two techniques, multi-frequency technique and incident field extraction technique, for further enhancing the performance of the microwave imaging technology in the field.

The present paper examines the architecture for a wireless structural health monitoring system for civil infrastructures. The primary objective of this architecture is the creation of a sensors network that is accurate, reliable, low cost, generic in form and easy to install and maintain. The key element of this architecture is a low power consumption multi-sensor modular unit. The paper summarizes the prototype design and implementation of the multi-sensor modular unit, using available technologies from the marketplace. The individual components are briefly presented and their selection criteria are discussed. The integrated prototype implementation is evaluated with multiple validation tests in a laboratory setting.

The SMART Layer (reg. TM) manufactured by Acellent is a thin flexible layer with a network of miniature piezoelectric actuators and sensors that can be embedded inside or mounted onto metal and composite structures to acquire information on structural integrity. Currently, SMART Layers (reg. TM) are used to assess the condition of structures and to monitor impact events. The layers can be used to perform built-in structural inspection by exciting the devices with a periodic or transient burst controlled input and analyzing the corresponding structural response. The technology can also be applied to areas concerned with Homeland Security. For example, the technology can be used for motion monitoring and monitoring of structures used in defense applications. By having a network of sensors that monitor loads on a structure, it is possible to monitor the movement of people by measuring the loads exerted by them. The SMART Layer (reg. TM) technology can be used to enhance the readiness of structures used for homeland defense such as manned and unmanned aircraft, missiles and radar systems. It can also be used to monitor a pipeline network for any terrorist related activity that can potentially damage the pipe system. A brief overview of such potential applications is presented here.

An automated in-situ road surface distress surveying and management system, AMPIS, has been developed on the basis of video images within the framework of GIS software. Video image processing techniques are introduced to acquire, process and analyze the road surface images obtained from a moving vehicle. ArcGIS platform is used to integrate the routines of image processing and spatial analysis in handling the full-scale metropolitan highway surface distress detection and data fusion/management. This makes it possible to present user-friendly interfaces in GIS and to provide efficient visualizations of surveyed results not only for the use of transportation engineers to manage road surveying documentations, data acquisition, analysis and management, but also for financial officials to plan maintenance and repair programs and further evaluate the socio-economic impacts of highway degradation and deterioration. A review performed in this study on fundamental principle of Pavement Management System (PMS) and its implementation indicates that the proposed approach of using GIS concept and its tools for PMS application will reshape PMS into a new information technology-based system that can provide convenient and efficient pavement inspection and management.

This paper addresses the development of a robust, low-cost, low power, and high performance autonomous wireless monitoring system for civil assets such as large facilities, new construction, bridges, dams, commercial buildings, etc. The role of the system is to identify the onset, development, location and severity of structural vulnerability and damage. The proposed system represents an enabling infrastructure for addressing structural vulnerabilities specifically associated with homeland security. The system concept is based on dense networks of “intelligent” wireless sensing units. The fundamental properties of a wireless sensing unit include: (a) interfaces to multiple sensors for measuring structural and environmental data (such as acceleration, displacements, pressure, strain, material degradation, temperature, gas agents, biological agents, humidity, corrosion, etc.); (b) processing of sensor data with embedded algorithms for assessing damage and environmental conditions; (c) peer-to-peer wireless communications for information exchange among units(thus enabling joint “intelligent” processing coordination) and storage of data and processed information in servers for information fusion; (d) ultra low power operation; (e) cost-effectiveness and compact size through the use of low-cost small-size off-the-shelf components. An integral component of the overall system concept is a decision support environment for interpretation and dissemination of information to various decision makers.

Polyvinylidene fluoride (PVDF) is a piezoelectric polymer material. One of its most attractive applications is being used as a sensor for structure monitoring. A suitable circuit interface plays an important role in sensor design. PVDF sensor can be used in a large variety of situations according to different design of circuit. The approach to a special circuit interface, which enables PVDF sensor to be utilized as a wireless “dynamic strain gage”, is presented in this paper. The wireless PVDF sensor was then tested and all the results have been compared with strain gage output for strain and displacement measurements.

In this paper a structural identification (St-Id) case study on a laboratory physical model is presented. The main objective is to understand the reliability of ambient monitoring as the principal global experimentation tool for St-Id and to address the issues related to the projection of the laboratory study to a bridge structure. Linear deterministic FE modeling, controlled static load tests, impact tests and ambient vibration tests are utilized as St-Id tools to supplement each other in the study. The results showed that even under controlled laboratory conditions, uncertainties in the St-Id process cannot be completely avoided and govern the reliability of an St-Id study. Issues regarding the successful application of ambient vibration testing on a real-life bridge structure based on laboratory model results are addressed.

Health monitoring of infrastructure systems for their proactive management to make the best use of limited resources for their optimum life-cycle performance, protection and preservation is a promising paradigm. Structural health monitoring (SHM) technologies have sufficiently evolved to accomplish real-time post-hazard evaluation of highway bridges. Solution of the pressing and critical problem of post-hazard bridge condition evaluation is possible by problem-focused, coordinated cross-disciplinary research. A newly initiated research program, which has been formulated for creating knowledge to construct an intelligent bridge SHM system, is presented in this paper. An overview of the state-of-the-art research in SHM is outlined.

This paper will present the concept of utilizing various mobile robotic platforms for homeland security. Highly specialized mobile robots equipped with the proper sensors and data processing capabilities have the ability to provide security and surveillance for a wide variety of applications. Large infrastructure components, such as bridges, pipelines, dams, and electrical power grids pose severe challenges for monitoring, surveillance, and protection against man-made and natural hazards. The structures are enormous, often with awkward and dangerous configurations that make it difficult, if not impossible, for continuous human surveillance. Properly outfitted robots have the potential to provide long-term surveillance without requiring continuous human supervision. Furthermore, these robotic platforms can have disaster mitigation capabilities such as evaluation of infrastructure integrity at the disaster site. The results presented will include proof-of-concept robotic platforms equipped with various sensor arrays, as well as discussion of design criteria for numerous homeland security applications.

The state of the practice of bridge inspection and bridge management in the United States is briefly discussed. This practice has many limitations. The most significant limitation is that the data collected is based solely upon visual inspection, augmented with limited mechanical methods such as hammer sounding or prying. Visual inspection is highly variable, subjective and inherently unable to detect invisible deterioration, damage or distress. There are many types of damage and deterioration that need to be detected and measured that are beyond the capabilities of visual inspection. Bridge performance also needs to be measured. The FHWA and many others have conducted research and development in technologies that can help meet these needs. Several examples illustrating the application of this technology for the long term monitoring of bridges are described. While the summary is not comprehensive it demonstrates that technology exists to meet the needs identified. Future directions and further application of bridge monitoring technology are also briefly discussed.

An effort is currently underway to create an Engineering Research Consortium Initiative (ERCI) focused on engineering and management of the highway transportation infrastructure. The goal of the ERCI will be to provide administrative and logistical support for a coordinated, problem-focused research program on the highway transportation infrastructure system. The cornerstone of the initiative will be field test-sites. Example sites might include major long span bridges, sample populations of operating bridges, decommissioned bridges, a regional network of highways and bridges, various types of pavement and geotechnical structures, or a major transportation hub serving a metropolitan area. Sites would be instrumented to collect a broad range of engineering (structural, geotechnical, hydraulic), human (traffic) and natural (climatological, seismological) response data. The field sites would be networked to provide real-time access to test facilities across the country; a secure central repository would be established for collecting data from the sites. The data and information gathered from these sites would be used by engineers and scientists to study the complex interactions and cause-and-effect relations of the various engineered, human and natural components of the highway hyper-system. A major research thrust of the ERCI will be security of the highway infrastructure system, with particular emphasis on bridges. The National Science Foundation and the Federal Highway Administration are expected to provide funding for the program through a joint agency initiative. Two workshops were recently held with experts from around the world to discuss the plans for the ERCI. The paper provides more details on the ERCI and the status of the effort to date.