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We are currently developing laser and electro-optic technologies to remotely measure Sodium (Na) by adapting existing lidar technology with space flight heritage. The developed instrumentation will serve as the core for the planni...
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We are currently developing laser and electro-optic technologies to remotely measure Sodium (Na) by adapting existing lidar technology with space flight heritage. The developed instrumentation will serve as the core for the planning of a Heliophysics mission targeted to study the composition and dynamics of Earths mesosphere based on a spaceborne lidar that will measure the mesospheric Na layer. There is a pressing need in the Ionosphere Thermosphere - Mesosphere (ITM) community for high-resolution measurements that can characterize small-scale dynamics (i.e. Gravity Waves with wavelengths smaller than a few hundred km) and their effects in the Mesosphere-Lower-Termosphere (MLT) on a global basis. This is compelling because they are believed to be the dominant contributors to momentum transport and deposition in the MLT, which largely drive the global circulation and thermal structure and interactions with the tides and planetary waves in this region. We are developing a spaceborne remote sensing technique that will enable acquisition of global Na density, temperature and wind measurements in the MLT with the spatial and temporal resolution required to resolve issues associated with the structure, chemistry, dynamics, and energetics of this regionA nadir-pointing spaceborne Na Doppler resonance fluorescence LIDAR on board of the ISS will essentially make high-resolution, in time and space, Na density, temperature and vertical wind measurements, from 75-115 km (MLT region). Our instrument concept consisted of a high-energy laser transmitter at 589 nm and highly sensitive photon counting detector that allows for range-resolved atmospheric-sodium-temperature profiles. The atmospheric temperature is deduced from the linewidth of the resonant fluorescence from the atomic sodium vapor D2 line as measured by our tunable laser. We are currently developing a high power energy laser that allows for some day time sodium lidar observations with the help of a narrow bandpass filter based on etalon or atomic sodium Faraday filter with 5 to 10 pm optical bandwidth. The current baseline detector for the lidar instrument is a 16-channel Photomultiplier Tube with receiver electronics that has been space-qualified for the ICESat-2ATLAS mission. Our technique uses the 16-channels as a photon-number-resolving single detector to provide the required full-spectroscopic sodium lineshape waveform for recovering Mesospheric temperature profiles. In this paper, we will describe our instrument concept for a future Heliophysics space mission based on board of the International Space Station (ISS).
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The Earth System Prediction Suite (ESPS) is a collection of flagship U.S. weather and climate models and model components that are being instrumented to conform to interoperability conventions, documented to follow metadata standa...
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The Earth System Prediction Suite (ESPS) is a collection of flagship U.S. weather and climate models and model components that are being instrumented to conform to interoperability conventions, documented to follow metadata standards, and made available either under open source terms or to credentialed users. The ESPS represents a culmination of efforts to create a common Earth system model architecture, and the advent of increasingly coordinated model development activities in the U.S. ESPS component interfaces are based on the Earth System Modeling Framework (SMF), community-developed software for building and coupling models, and the National Unified Operational Prediction Capability (NUOPC) Layer, a set of ESMF-based component templates and interoperability conventions. This shared infrastructure simplifies the process of model coupling by guaranteeing that components conform to a set of technical and semantic behaviors. The ESPS encourages distributed, multi-agency development of modeling systems, controlled experimentation and testing, and exploration of novel model configurations, such as those motivated by research involving managed and interactive ensembles. ESPS codes include the Navy Global Environmental Model (NavGEM), HYbrid Coordinate Ocean Model (HYCOM), and Coupled Ocean Atmosphere Mesoscale Prediction System (COAMPS); the NOAA Environmental Modeling System (NEMS) and the Modular Ocean Model (MOM); the Community Earth System Model (CESM); and the NASA ModelE climate model and GEOS-5 atmospheric general circulation model.
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The research team developed a comprehensive Benefit/Cost (B/C) analysis framework to evaluate existing and anticipated intelligent transportation system (ITS) strategies, particularly, adaptive traffic control systems and ramp met...
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The research team developed a comprehensive Benefit/Cost (B/C) analysis framework to evaluate existing and anticipated intelligent transportation system (ITS) strategies, particularly, adaptive traffic control systems and ramp metering systems, in terms of the triple bottom line (TBL) of sustainability (i.e. social, economic, and environmental impacts). The B/C framework for each ITS category was divided into four main areas: Life Cycle Cost Analysis, Analysis of Benefits through Travel Time Savings, Analysis of Benefits through Reductions in Energy Consumption, and Analysis of Benefits through Safety Enhancements. The life cycle cost analysis of an ITS deployment includes infrastructure costs, incremental costs, and O&M costs. The analysis of benefits through travel time savings was grouped into recurring travel time savings analysis and nonrecurring travel time savings analysis. The analysis of benefits through reductions in energy consumption was conducted using a newly-built microscopic scale top-down approach. Analysis of benefits through safety enhancements was mainly focused on fatal crashes. According to the results, the Benefit/Cost ratio (BCR) for a typical ATCS deployment may range between 6.52 and 13.04; whereas the BCR for a typical ramp metering deployment is expected to be around 6.44. We consider the results obtained from our B/C framework as conservative, which means that BCRs calculated in our study can be lower than specific ATCS and ramp metering deployments around the United States.
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NASA’s Goddard Space Flight Center (GSFC) is working on maturing the technology readiness of a laser transmitter designed for use in atmospheric CO2 remote-sensing. GSFC has been developing an airplane-based CO2 lidar instrument ...
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NASA’s Goddard Space Flight Center (GSFC) is working on maturing the technology readiness of a laser transmitter designed for use in atmospheric CO2 remote-sensing. GSFC has been developing an airplane-based CO2 lidar instrument over several years to demonstrate the efficacy of the instrumentation and measurement technique and to link the science models to the instrument performance. The ultimate goal is to make space-based satellite measurements with global coverage. In order to accomplish this, we must demonstrate the technology readiness and performance of the components as well as demonstrate the required power-scaling to make the link with the required signal-to-noise-ratio (SNR). To date, all the instrument components have been shown to have the required performance with the exception of the laser transmitter.In this program we are working on a fiber-based master oscillator power amplifier (MOPA) laser transmitter architecture where we will develop a ruggedized package and perform the relevant environmental tests to demonstrate TRL-6. In this paper we will review our transmitter architecture and progress on the performance and packaging of the laser transmitter.
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Specifications for ready-mixed concrete limit drum revolution and mixing time to 250 drum revolutions and/or 1.5 hours before discharge. These specifications have been in place for many years with the objective of ensuring the qua...
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Specifications for ready-mixed concrete limit drum revolution and mixing time to 250 drum revolutions and/or 1.5 hours before discharge. These specifications have been in place for many years with the objective of ensuring the quality and performance of the finished concrete product; however, these limitations could potentially increase construction costs without additional benefits, especially when longer transport distances are required. Because there have been significant changes in concrete constituent materials (e.g., chemical admixtures) and equipment since these limits were first implemented, research is needed to assess the effects of time to discharge and drum revolution counts on concrete performance. The objective of this research program is to evaluate and verify whether existing specifications for mixing and transporting concrete are applicable for today’s materials and equipment and if not, to identify key variables or tests that can ensure adequate placeability and good mechanical and durability characteristics. This study evaluated the influence of coarse and fine aggregate, supplementary cementitious materials quantity and type, chemical admixtures, temperature and mixing time and drum revolution on the mechanical and durability characteristics of concrete. Results indicate that existing specifications may be appropriate due to loss of workability. However, mixing time and drum revolution counts had no significant effects on the majority of mechanical properties and durability characteristics of ready-mixed concrete and results from this research indicate that existing specification limits are very conservative.
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The prime motivation of the project at McMaster University was to carry out the critical evaluation and compilation of Nuclear Structure and Decay data, and of nuclear astrophysics data with continued participation in the United S...
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The prime motivation of the project at McMaster University was to carry out the critical evaluation and compilation of Nuclear Structure and Decay data, and of nuclear astrophysics data with continued participation in the United States Nuclear Data Program (US-NDP). A large body of evaluated and compiled structure data were supplied for databases such as ENSDF, XUNDL, NSR, etc. residing on webpage of National Nuclear Data Center of the Brookhaven National Laboratory, Upton, New York, USA. Thermonuclear reaction rates of importance to stellar explosions, such as novae, x-ray bursts and supernovae, were evaluated as well. This effort was closely coupled to our ongoing experimental effort, which took advantage of radioactive ion beam and stable beam facilities worldwide to study these key reaction rates. This report contains brief descriptions of the various activities together with references to all the publications in peer-reviewed journals which were the result of work carried out with the award DE-FG02-98-ER41080, during 1998-2013.
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The cDNA of a NADH dehydrogenase-ubiquinone Fe-S protein 8 subunit (NDUFS8) gene from Aedes (Ochlerotatus) taeniorhynchus Wiedemann has been cloned and sequenced. The 824 bp full-length mRNA sequence of AetNDUFS8 encodes an open r...
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The cDNA of a NADH dehydrogenase-ubiquinone Fe-S protein 8 subunit (NDUFS8) gene from Aedes (Ochlerotatus) taeniorhynchus Wiedemann has been cloned and sequenced. The 824 bp full-length mRNA sequence of AetNDUFS8 encodes an open reading region of 651 bp (that is, 217 amino acids). To identify if AetNDUFS8 is developmentally regulated, we employed a quantitative real-time polymerase chain reaction to examine AetNDUFS8 gene expression levels in all developmental stages of Ae. taeniorhynchus. In egg, larval, and pupal stages, AetNDUFS8 was expressed at relatively low levels. However, in the teneral adult stage, AetNDUFS8 was highly expressed. During the time course study in response to permethrin pesticide treatment, quantitative real-time polymerase chain reaction (PCR) also showed that mRNA transcription levels of AetNDUFS8 were regulated in female Ae. taeniorhynchus. A mitochondrially encoded NADH dehydrogenase subunit 5 AetNADH5 was highly expressed in different developmental stages of Ae. taeniorhynchus. This study suggests that AetNDUFS8 and AetNADH5 play an essential role in the development of Ae. taeniorhynchus and will provide information useful for developing dsRNA pesticide for mosquito control.
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A new method has been developed to analyze high-resolution spectral data of the solar photosphere and chromosphere. The data format is a two-dimensional (2-D) time-series of images. The method uses emission or absorption lines in ...
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A new method has been developed to analyze high-resolution spectral data of the solar photosphere and chromosphere. The data format is a two-dimensional (2-D) time-series of images. The method uses emission or absorption lines in the intensity and polarization data (Stokes parameters). Each pixel contains quantitative information on the spectral profiles of selected lines, such as the line width, degree of asymmetry, and peakedness. The 2-D time-series is first averaged in time pixel-by-pixel. A derivative time-series is constructed such that each image in the time-series is characterized by the pixel-by-pixel deviations from the average. The pixel fluctuation distribution (PFD) function is constructed and its statistical properties are calculated. Such properties including the mean, variance, skewness, and kurtosis are computed as functions of time and are used to precisely quantify temporal variations in the observed spectral data. In this work, the method is applied to photospheric absorption lines (Fe I 6301.5 and 6302.5 ) from quiet-Sun regions and active regions on the solar photosphere, obtained by the vector spectromagnetograph (VSM) of the Synoptic Optical Long-term Investigations of the Sun (SOLIS) of the National Solar Observatory (NSO).
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Shape engineering is crucial for controlling the properties and functions of polymers, such as surface roughness, adhesion and wettability, pore size and connection, chirality, and responsiveness towards environmental stimuli, whi...
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Shape engineering is crucial for controlling the properties and functions of polymers, such as surface roughness, adhesion and wettability, pore size and connection, chirality, and responsiveness towards environmental stimuli, which enable a broad range of applications in microfluidics, tissue engineering, switchable adhesives, soft robotics, optical devices, and reconfigurable metamaterials. Conventional plastic-shaping techniques like molding depend on complementary replication of the geometry from a physical mold. The cost and time associated with tools and machining used in such a one-to-one linear shape-translation processes often increase rapidly with shape complexity. Additive manufacturing, also called three-dimensional (3D) printing, is a layer-by-layer technology for producing 3D objects directly from a digital model. While 3D printing allows the fabrication of increasingly sophisticated structures on demand, the production time scales signifi cantly with object size. 3D structures of gels and polymers based on bending or swelling have also been fabricated using localized light or heat. Alternatively, non-uniform shape change of heterogeneous multicomponent or multicompartmental materials in response to global environmental stimuli has been exploited to create origami structures. However, the degree of sophistication in applying localized stimuli or fabrication of multicomponent and multicompartmental materials usually correlates with 3D shape complexity.
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Development of reliable magnesium (Mg) to steel joining methods is one of the critical issues in broader applications of Mg in automotive body construction. Ultrasonic spot welding (USW) has been demonstrated successfully to join ...
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Development of reliable magnesium (Mg) to steel joining methods is one of the critical issues in broader applications of Mg in automotive body construction. Ultrasonic spot welding (USW) has been demonstrated successfully to join Mg to steel and to achieve strong joints. In this study, corrosion test of ultrasonic spot welds between 1.6 mm thick Mg AZ31BH24 and 0.8 mm thick galvanized mild steel, without and with adhesive, was conducted. Adhesive used was a onecomponent, heat-cured epoxy material, and was applied between overlapped sheets before USW. Corrosion test was conducted with an automotive cyclic corrosion test, which includes cyclic exposures of dipping in the 0.5% sodium chloride (NaCl) bath, a constant humidity environment, and a drying period. Lap shear strength of the joints decreased with the cycles of corrosion exposure. Good joint strengths were retained at the end of 30-cycle test. Failure mode of joints without adhesive was Mg nugget pull-out, but was interfacial failure of samples with adhesive. Metal-metal bonding between Mg and steel was maintained throughout 30 cycles of corrosion exposure. Joint strength of corroded samples without adhesive decreased due to the erosion in the joint and in the parent material. For the samples with adhesive, the joint strength decreased due to the corrosion attack at the joint interface and the delamination of adhesive from Mg sheet. Adhesive was shown to help in minimizing the erosion of the interior surface of Mg sheet.
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