Engineering topics
Publications and source records attributed to Johnson, Robert.
This award supported work on the Heavy Photon Search (HPS) experiment by three members of the Santa Cruz Institute for Particle Physics: Robert Johnson (professor), Vitaliy Fadeyev (physicist), and Alic Spellman (graduate student), from September 2018 through March 2020.
Congress created the Chemical Stockpile Emergency Preparedness Program (CSEPP) in 1985 (U.S. Department of Defense [DOD] Authorization Act, 1986, Public Law 99-145) to provide emergency preparedness assistance and resources to communities surrounding Army chemical warfare agent stockpiles. CSEPP is a partnership between the Federal Emergency Management Agency (FEMA) and the U.S. Department of the Army (Army), and includes elements of the federal, state, and local government at each of the stockpile sites.
We report on the influence of sintering gas atmosphere on the thermoelectric (TE) performance of Ca 3 Co 4 O 9+δ ceramics made from precursor powders synthesized using chemical sol–gel route. Two sets of polycrystalline pellets were sintered in air and oxygen atmosphere, respectively. Sintering gas atmosphere and sintering temperature were found to have great influence on the Ca 3 Co 4 O 9+δ crystal orientation and formation of the Co 3 O 4 secondary phase. All samples, regardless of sintering atmosphere, had similar Seebeck coefficients S that increased with measurement temperature. By contrast, the electrical resistivity ρ changed dramatically as the sintering temperature and atmosphere changed. For samples sintered in air, when the sintering temperature is above 1193 K, ρ increased as the sintering temperature increased. For samples sintering in oxygen, ρ decreased monotonically as the sintering temperature increased up to 1253 K. Benefited from the reduced ρ, the electrical power factor of the sample sintered in the oxygen at 1253 K is 0.539 mW m –1 K –2 , and 40% greater than that from the sample sintered at 1193 K in air. Dimensionless figure-of-merit ZT of the sample sintered at 1253 K in oxygen is 0.28 at 1073 K, which is 20% greater than that of samples sintered in air at 1193 K. Overall, the highest TE performance was obtained for Ca 3 Co 4 O 9+δ ceramics sintered in oxygen at 1253 K, which is significantly higher than the Ca 3 Co 4 O 9+δ decomposition temperature of 1199 K in air.
This paper is intended to help inform future technology deployment opportunities for connected thermostats (CTs), based on investigation and review of the U.S. residential housing and CT markets, as well as existing, emerging, and future use cases for CT hardware and CT-generated data. The CT market has experienced tremendous growth over the last 5 years—both in terms of the number of units sold and the number of firms offering competing products—and can be characterized by its rapid pace of technological innovation. Despite many assuming CTs would become powerful tools for increasing comfort while saving energy, there remains a great deal of uncertainty about the actual energy and cost savings that are likely to be realized from deployment of CTs, particularly under different conditions.
This paper is intended to help inform future technology deployment opportunities for connected thermostats (CTs), based on investigation and review of the U.S. residential housing and CT markets, as well as existing, emerging, and future use cases for CT hardware and CT-generated data. The CT market has experienced tremendous growth over the last five years — both in terms of the number of units sold and the number of firms offering competing products — and can be characterized by its rapid pace of technological innovation. Despite many assuming CTs would become powerful tools for increasing comfort while saving energy, there remains a great deal of uncertainty about the actual energy and cost savings that are likely to be realized from deployment of CTs, particularly under different conditions.
Unmanned Aircraft Systems (UASs) have made dramatic technical advances in the past decade. Their use domestically is currently tightly constrained by existing Federal Aviation Administration (FAA) regulations. Within the next few years, the FAA is expected to provide a regulatory framework that allows for a greatly expanded role for UASs in domestic airspace for a wide variety of applications. One of those will be remote sensing for land and natural resource monitoring. While there has recently been a large body of published research on UAS applications to environmental monitoring, in practice, very little has been operationalized by private or public entities to date. In July 2014, Argonne National Laboratory hosted a workshop dedicated to environmental monitoring UAS applications with attendance by representatives from 11 federal agencies as well as academics. The workshop reviewed the UAS state-of-the-art within the federal arena and barriers to broader UAS use. While a number of agencies, the including National Oceanic and Atmosphere Administration, the United States Geological Survey, National Aeronautics and Space Administration, and the Bureau of Land Management have conducted proof-of-concept UAS demonstrations, typically using surplus Department of Defense equipment, the promise of UAS systems at the moment remains untapped for a variety of reasons. The consensus was, however, that UAS systems will play an increasingly important role in cost-effectively supporting timely natural-resource and land-management monitoring needs. Environmental Practice 17: 170–177 (2015)
An intelligent autonomous control capability has been developed and is currently being validated in ground cryogenic fluid management operations. The capability embodies a physical architecture consistent with typical launch infrastructure and control systems, augmented by a higher level autonomous control (AC) system enabled to make knowledge-based decisions. The AC system is supported by an integrated system health management (ISHM) capability that detects anomalies, diagnoses causes, determines effects, and could predict future anomalies. AC is implemented using the concept of programmed sequences that could be considered to be building blocks of more generic mission plans. A sequence is a series of steps, and each executes actions once conditions for the step are met (e.g. desired temperatures or fluid state are achieved). For autonomous capability, conditions must consider also health management outcomes, as they will determine whether or not an action is executed, or how an action may be executed, or if an alternative action is executed instead. Aside from health, higher level objectives can also drive how a mission is carried out. The capability was developed using the G2 software environment (www.gensym.com) augmented by a NASA Toolkit that significantly shortens time to deployment. G2 is a commercial product to develop intelligent applications. It is fully object oriented. The core of the capability is a Domain Model of the system where all elements of the system are represented as objects (sensors, instruments, components, pipes, etc.). Reasoning and decision making can be done with all elements in the domain model. The toolkit also enables implementation of failure modes and effects analysis (FMEA), which are represented as root cause trees. FMEA's are programmed graphically, they are reusable, as they address generic FMEA referring to classes of subsystems or objects and their functional relationships. User interfaces for integrated awareness by operators have been created.
As part of the ongoing remediation process at the Maywood Formerly Utilized Sites Remedial Action Program (FUSRAP) properties, Argonne National Laboratory (Argonne) assisted the U.S. Army Corps of Engineers (USACE) New York District by providing contaminated soil volume estimates for the main site area, much of which is fully or partially remediated. As part of the volume estimation process, an initial conceptual site model (ICSM) was prepared for the entire site that captured existing information (with the exception of soil sampling results) pertinent to the possible location of surface and subsurface contamination above cleanup requirements. This ICSM was based on historical anecdotal information, aerial photographs, and the logs from several hundred soil cores that identified the depth of fill material and the depth to bedrock under the site. Specialized geostatistical software developed by Argonne was used to update the ICSM with historical sampling results and down-hole gamma survey information for hundreds of soil core locations. The updating process yielded both a best guess estimate of contamination volumes and a conservative upper bound on the volume estimate that reflected the estimate's uncertainty. Comparison of model results to actual removed soil volumes was conducted on a parcel-by-parcel basis. Where sampling data density was adequate, the actual volume matched the model's average or best guess results. Where contamination was un-characterized and unknown to the model, the actual volume exceeded the model's conservative estimate. Factors affecting volume estimation were identified to assist in planning further excavations. (authors)
As part of the ongoing remediation process at the Maywood Formerly Utilized Sites Remedial Action Program properties, Argonne National Laboratory assisted the U.S. Army Corps of Engineers (USACE) New York District in revising contaminated soil volume estimates for the remaining areas of the Stepan/Sears properties that require soil remediation. As part of the volume estimation process, an initial conceptual site model (ICSM) was prepared for the entire site that captured existing information (with the exception of soil sampling results) pertinent to the possible location of surface and subsurface contamination above cleanup requirements. This ICSM was based on historical anecdotal information, aerial photographs, and the logs from several hundred soil cores that identified the depth of fill material and the depth to bedrock under the site. Specialized geostatistical software developed by Argonne was used to update the ICSM with historical sampling results and down-hole gamma survey information for hundreds of soil core locations; both sampling results and down-hole gamma data were coded to identify whether the results indicated the presence of contamination above site cleanup requirements. Significant effort was invested in developing complete electronic data sets for the site by incorporating data contained in various scanned documents, maps, etc. The updating process yielded both a best guess estimate of contamination volumes and upper and lower bounds on the volume estimate that reflected the estimate's uncertainty. The site-wide contaminated volume estimate (with associated uncertainty) was adjusted to reflect areas where remediation was complete; the result was a revised estimate of the remaining soil volumes requiring remediation that the USACE could use for planning. Other environmental projects may benefit from this process for estimating the volume of contaminated soil. A comparison of sample and DHG results for various stations with the site ICSM provides one measure of the quality of site understanding relative to the presence of contamination and its likely extent. A second measure of the quality of a contaminated soil volume estimate, in the case of BAASS, is a comparison of the best guess volume estimate with the conservative volume estimate. For Maywood, the conservative volume estimate is more than double the best guess. The data available for the site indicate that the preponderance of this difference is attributable to uncertainty about the exact depth of known contamination. The observed depth of contamination based on sample results and DHG data often varied significantly among adjacent soil cores. In the case of Maywood, where a significant amount of remediation has already taken place, a third measure of the quality of the volume estimates is the retrospective estimate of contaminated soil volumes for areas that have already been remediated [2]. The USACE is currently comparing the latest BAASS volume estimates for those areas with records indicating what was actually removed. (authors)
Rapid thermospheric flows can significantly enhance the estimates of the atmospheric loss rate and the structure of the atmospheric corona of a planetary body. In particular, rapid horizontal flow at the exobase can increase the corresponding constituent escape rate. Here we show that such corrections, for both thermal and non-thermal escape, cannot be ignored when calculating the escape of methane from Titan, for which drastically different rates have been proposed. Such enhancements are also relevant to Pluto and exoplanets.
In a recent paper, Sittler et al., (2010) presented new results on the T9 encounter by the Cassini spacecraft when it passed through Titan s induced magnetotail. Two crossings were observed, but the first crossing, event 1, is thought to be out flowing ionosphere plasma. T9 is ideal for CAPS IMS probing of the ionosphere, since the ion densities at the higher altitudes of the T9 flyby approx. 10,000 km, allows measurements to be made down to 1 eV without saturating its detectors. Sittler et al., (2010) reported possible detection of NH4+ ions, but favored the detection of CH5+ and C2H5+ ions. In this report we investigate both the medium mass resolution (straight through (ST)) and high mass resolution (linear electric field (LEF)) composition data from the Cassini Plasma Spectrometer (CAPS) Ion Mass Spectrometer (IMS). We present a more in depth analysis of the composition data and make comparisons with ionospheric models including nitrogen chemistry such as that by Vuitton et al. (2007). The LEF data does not support NH4+ identification, but favors a CH5+ and C2H5+ identification, but also molecular ions C2N+ and CH2NH2+ are chemically allowed possibilities.
On January 14, 2004, the President of the United States unveiled a new vision for robotic and human exploration of space entitled, "A Renewed Spirit of Discovery". As stated by the President in the Vision for Space Exploration (VSE), NASA must "... implement a sustained and affordable human and robotic program to explore the solar system and beyond " and ".. .develop new technologies and harness the moon's abundant resources to allow manned exploration of more challenging environments." A key to fulfilling the goal of sustained and affordable human and robotic exploration will be the ability to use resources that are available at the site of exploration to "live off the land" instead of bringing everything from Earth, known as In-Situ Resource Utilization (ISRU). ISRU can significantly reduce the mass, cost, and risk of exploration through capabilities such as: mission consumable production (propellants, fuel cell reagents, life support consumables, and feedstock for manufacturing & construction); surface construction (radiation shields, landing pads, walls, habitats, etc.); manufacturing and repair with in-situ resources (spare parts, wires, trusses, integrated systems etc.); and space utilities and power from space resources. On January 27th, 2004 the President's Commission on Implementation of U.S. Space Exploration Policy (Aldridge Committee) was created and its final report was released in June 2004. One of the report's recommendations was to establish special project teams to evaluate enabling technologies, of which "Planetary in situ resource utilization" was one of them. Based on the VSE and the commission's final report, NASA established fifteen Capability Roadmap teams, of which ISRU was one of the teams established. From Oct. 2004 to May 2005 the ISRU Capability Roadmap team examined the capabilities, benefits, architecture and mission implementation strategy, critical decisions, current state-of-the-art (SOA), challenges, technology gaps, and risks of ISRU for future human Moon and Mars exploration. This presentation will provide an overview of the ISRU capability, architecture, and implementation strategy examined by the ISRU Capability Roadmap team, along with a top-level review of ISRU benefits, resources and products of interest, and the current SOA in ISRU processes and systems. The presentation will also highlight the challenges of incorporating ISRU into future missions and the gaps in technologies and capabilities that need to be filled to enable ISRU.
A field-programmable gate array (FPGA) on a single lightweight, low-power integrated-circuit chip has been developed to implement an azimuth pre-filter (AzPF) for a synthetic-aperture radar (SAR) system. The AzPF is needed to enable more efficient use of data-transmission and data-processing resources: In broad terms, the AzPF reduces the volume of SAR data by effectively reducing the azimuth resolution, without loss of range resolution, during times when end users are willing to accept lower azimuth resolution as the price of rapid access to SAR imagery. The data-reduction factor is selectable at a decimation factor, M, of 2, 4, 8, 16, or 32 so that users can trade resolution against processing and transmission delays. In principle, azimuth filtering could be performed in the frequency domain by use of fast-Fourier-transform processors. However, in the AzPF, azimuth filtering is performed in the time domain by use of finite-impulse-response filters. The reason for choosing the time-domain approach over the frequency-domain approach is that the time-domain approach demands less memory and a lower memory-access rate. The AzPF operates on the raw digitized SAR data. The AzPF includes a digital in-phase/quadrature (I/Q) demodulator. In general, an I/Q demodulator effects a complex down-conversion of its input signal followed by low-pass filtering, which eliminates undesired sidebands. In the AzPF case, the I/Q demodulator takes offset video range echo data to the complex baseband domain, ensuring preservation of signal phase through the azimuth pre-filtering process. In general, in an SAR I/Q demodulator, the intermediate frequency (fI) is chosen to be a quarter of the range-sampling frequency and the pulse-repetition frequency (fPR) is chosen to be a multiple of fI. The AzPF also includes a polyphase spatial-domain pre-filter comprising four weighted integrate-and-dump filters with programmable decimation factors and overlapping phases. To prevent aliasing of signals, the bandwidth of the AzPF is made 80 percent of fPR/M. The choice of four as the number of overlapping phases is justified by prior research in which it was shown that a filter of length 4M can effect an acceptable transfer function. The figure depicts prototype hardware comprising the AzPF and ancillary electronic circuits. The hardware was found to satisfy performance requirements in real-time tests at a sampling rate of 100 MHz.
Fiber formation from murine serum amyloid A1 (SAA) was compared to the linear aggregation and fiber formation of colloidal gold particles. Here we report the similarities of these processes. Upon incubation with acetic acid, SAA misfolds and adopts a new conformation, which we termed saa. saa apparently is less soluble than SAA in aqueous solution; it aggregates and forms nucleation units and then fibers. The fibers appear as a string of the nucleation units. Additionally, an external electric field promotes saa fiber formation. These properties of saa are reminiscent of colloidal gold formation from gold ions and one-dimensional aggregation of the gold colloids. Colloidal gold particles were also found to be capable of aggregating one-dimensionally under an electric field or in the presence of polylysine. These gold fibers resembled in structure that of saa fibers. In summary, protein aggregation and formation of fibers appear to follow the generalized principles derived in colloidal science for the aggregation of atoms and molecules, including polymers such as polypeptides. The analysis of colloidal gold formation and of one-dimensional aggregation provides a simple model system for the elucidation of some aspects of protein fiber formation.