Recent advances in sensory devices using radio frequency identification (RFID) led to applications such as monitoring the temperature during the transportation of heat sensitive products where recorded data can be use...
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Recent advances in sensory devices using radio frequency identification (RFID) led to applications such as monitoring the temperature during the transportation of heat sensitive products where recorded data can be used to detect refrigeration equipment failure along the supply chain or estimate remaining shelf life of the product. For the project discussed in this paper, a handheld based portable RFID system is used to track the storage and transportation temperatures of perishable products using battery assisted passive temperature tags. The information from the tags is used in shelf life prediction models to estimate the remaining shelf life based on the recorded temperature data to provide a dynamic expiration date. Instead of the full application development effort, this paper focuses on the unique project requirements and challenges which led to the introduction of three novel concepts related to RFID enabled temperature tracking systems. First, due to absence of a common standard for testing RFID temperature tags, we develop a requirement driven, comprehensive testing protocol combining statistical tools and common industry standards with the help of a uniquely designed test setup to realistically simulate and evaluate the real life performances of different temperature tags. Next, a novel context based accuracy metric is derived for objective and application (such as shelf life prediction) specific comparison of different technologies. Finally, a pallet temperature estimation algorithm is developed to overcome some of the physical difficulties encountered in reading ultra-high frequency tags near the presence of metals and liquids.
Recent research interest in organic field-effect transistor (FET) memory has shifted to the functionality of photoprogramming in terms of its potential uses in multibit datastorage and light-assisted encryption and i...
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Recent research interest in organic field-effect transistor (FET) memory has shifted to the functionality of photoprogramming in terms of its potential uses in multibit datastorage and light-assisted encryption and its low-energy consumption and broad response to various optical bands. Phototransistor memory can be modulated through both electrical stress and light illumination, allowing it to function as an orthogonal operation method without mutual interference. Herein, the basic design concepts, requirements, and architectures of phototransistor memory are introduced. Design architectures such as channel-only, channel-with-photogate, photochromatic channel devices and floating gate, photoactive polymer, and organic molecule-based electrets are systematically categorized. The operational mechanism and impact of effective combinations of channels and electrets are reviewed to provide a fundamental understanding of photoprogramming as well as its potential future developmental applications as nonvolatile memory. Furthermore, recent advances in phototransistors and their diverse applications, including nonvolatile memory, artificial synapses, and photodetectors, are summarized. Finally, the outlook for the future development of phototransistors is briefly discussed. A comprehensive picture of the recent progress in phototransistors is provided.
There are various technologies available for the acquisition and display of digital radiographic images. A division has historically existed between “computed radiography” (CR) using photostimulable storage phosphor...
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There are various technologies available for the acquisition and display of digital radiographic images. A division has historically existed between “computed radiography” (CR) using photostimulable storage phosphors placed in a cassette holder with subsequent processing in a reader, and “direct radiography” (DR) using a detector with integrated electronics and direct readout and image display. In 2005, these distinctions are less obvious, as some storage phosphor (PSP) devices are automated with direct image display, and some direct flat‐panel devices are used like a portable cassette. Generally speaking, rather than distinguishing digital detectors based on “CR versus DR”, consideration of cassette versus cassetteless digital radiography is perhaps warranted as the technologyadvances. Besides the venerable cassette‐based PSP detector and plate reader for large field of view imaging (35 × 43 cm), digital detector technologies now available include PSP line‐scan systems in a cassetteless enclosure, optically coupled CCD‐camera systems, fiber‐optically coupled slot‐scan CCD array detectors, indirect x‐ray conversion scintillators and thin‐film‐transistor (TFT) photodiode arrays, and direct x‐ray conversion semiconductors layered on TFT detector arrays. Dedicated digital mammography detectors use similar technologies, with appropriate tuning for resolution and speed. Detective quantum efficiency measurements, equipment specifications, unique acquisition techniques (e.g., digital tomosynthesis and dual energy radiography), PACS/RIS integration and quality control issues are reviewed in the presentation. Educational Objectives: 1. To describe digital radiography in general terms, and compare with screen‐film detectors 2. To understand acquisition and information flow of digital radiography devices 3. To compare cassette and cassetteless operation in terms of resolution, dose efficiency and signal to noise ratio 4. To describe new data acquisition and image processing t
An important part of any CO2 geosequestration project is to ensure CO2 containment and conformance in the subsurface. This is generally done by implementing a comprehensive, risk-based Measurement, Monitoring and Veri...
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An important part of any CO2 geosequestration project is to ensure CO2 containment and conformance in the subsurface. This is generally done by implementing a comprehensive, risk-based Measurement, Monitoring and Verification plan, a key element of which is active time-lapse seismic monitoring. However, high cost and environmental impact of the standard surface seismic monitoring dictate the need for a cost-effective and environmentally friendly alternative. An opportunity to develop such method emerges with advances in distributed acoustic sensing (DAS) technology, which turns an optical fibre into a seismic sensor with dense spatial sampling. DAS can be permanently deployed in multiple wells across the geosequestration site providing a robust and non-intrusive network of seismic receivers. This approach was developed and tested in the CO2CRC Otway project, where injection of 15 kt of CO2 at 1.5 km depth was monitored with a 4D vertical seismic profiling (VSP) using five borehole DAS arrays and mobile vibroseis sources. The 4D DAS VSP in each of the five wells provides broadly consistent images of the CO2 plume with some differences due to different illumination of the target horizon, lateral variation of velocities, and seismic anisotropy. When the newly injected CO2 reaches a CO2 plume created as a result of an earlier injection into the same formation similar to 600 m updip, 4D DAS VSP shows a change in reflectivity in that area and beyond. This shows a potential of 4D DAS VSP for monitoring gas injection into gas-saturated reservoirs.
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