364 research outputs found
Identifying Optimal Temporal Scale for the Correlation of AOD and Ground Measurements of PM2.5 to Improve the Modeling Performance in a Real-Time Air Quality Estimation System
Aerosol optical depth (AOD), derived from satellite measurements using Moderate Resolution Imaging Spectrometer (MODIS), offers indirect estimates of particle matter. Research shows a significant positive correlation between satellite-based measurements of AOD and ground-based measurements of particulate matter with aerodynamic diameter less than or equal to 2.5 micrometers (PM2.5). In addition, satellite observations have also shown great promise in improving estimates of PM2.5 air quality surface. Research shows that correlations between AOD and ground PM2.5 are affected by a combination of many factors such as inherent characteristics of satellite observations, terrain, cloud cover, height of the mixing layer, and weather conditions, and thus might vary widely in different regions, different seasons, and even different days in a same location. Analysis of correlating AOD with ground measured PM2.5 on a day-to-day basis suggests the temporal scale, a number of immediate latest days for a given run's day, for their correlations needs to be considered to improve air quality surface estimates, especially when satellite observations are used in a real-time pollution system. The second reason is that correlation coefficients between AOD and ground PM2.5 cannot be predetermined and needs to be calculated for each day's run for a real-time system because the coefficients can vary over space and time. Few studies have been conducted to explore the optimal way to apply AOD data to improve model accuracies of PM2.5 surface estimation in a real-time air quality system. This paper discusses the best temporal scale to calculate the correlation of AOD and ground particle matter data to improve the results of pollution models in real-time system
CARMA: Context-Aware Runtime Reconfiguration for Energy-Efficient Sensor Fusion
Autonomous systems (AS) are systems that can adapt and change their behavior
in response to unanticipated events and include systems such as aerial drones,
autonomous vehicles, and ground/aquatic robots. AS require a wide array of
sensors, deep-learning models, and powerful hardware platforms to perceive and
safely operate in real-time. However, in many contexts, some sensing modalities
negatively impact perception while increasing the system's overall energy
consumption. Since AS are often energy-constrained edge devices,
energy-efficient sensor fusion methods have been proposed. However, existing
methods either fail to adapt to changing scenario conditions or to optimize
energy efficiency system-wide. We propose CARMA: a context-aware sensor fusion
approach that uses context to dynamically reconfigure the computation flow on a
Field-Programmable Gate Array (FPGA) at runtime. By clock-gating unused sensors
and model sub-components, CARMA significantly reduces the energy used by a
multi-sensory object detector without compromising performance. We use a
Deep-learning Processor Unit (DPU) based reconfiguration approach to minimize
the latency of model reconfiguration. We evaluate multiple
context-identification strategies, propose a novel system-wide
energy-performance joint optimization, and evaluate scenario-specific
perception performance. Across challenging real-world sensing contexts, CARMA
outperforms state-of-the-art methods with up to 1.3x speedup and 73% lower
energy consumption.Comment: Accepted to be published in the 2023 ACM/IEEE International Symposium
on Low Power Electronics and Design (ISLPED 2023
Evaluation of a Method of Estimating Agricultural Chemical Use
This research evaluated the validity of an economic-based measure of agricultural chemical use on specific crop types. Estimated chemical use measures, reported in a budget planning document prepared collaboratively with input from farmers, vendors, researchers, and representatives from numerous agricultural agencies, were compared to chemical use measures collected through face-to-face interviews with local farmers regarding their actual chemical application practices over the past growing season. A rural agricultural-based county in Mississippi, USA, was the study area for this project. The measures of comparison were the estimated and actual ounces of individual fungicides, herbicides, and insecticides used per acre on corn, rice, soybean, wheat, and cotton fields, and the estimated and actual total chemical load, which is the sum of all fungicides, herbicides and insecticides used on the various crops. To obtain information regarding crop type and area of cultivated land, contemporary satellite images, overlaid with property maps, were plotted and provided for the farmers to identify their crop types and delineate their crop boundaries. The crop boundaries were digitized, and a GIS database was developed containing data for crop types, amounts of cultivated land, and chemical types and quantities used. Outcomes of this research could assist in studies requiring agricultural chemical data by using estimates generated by the USDA and other agricultural agencies as an alternative to primary data collection
ATP-Binding Cassette Transporter VcaM from Vibrio cholerae is Dependent on the Outer Membrane Factor Family for Its Function.
Vibrio cholerae ATP-binding cassette transporter VcaM (V. cholerae ABC multidrug resistance pump) has previously been shown to confer resistance to a variety of medically important drugs. In this study, we set to analyse its properties both in vitro in detergent-solubilised state and in vivo to differentiate its dependency on auxiliary proteins for its function. We report the first detailed kinetic parameters of purified VcaM and the rate of phosphate (Pi) production. To determine the possible functional dependencies of VcaM on the tripartite efflux pumps we then utilized different E. coli strains lacking the principal secondary transporter AcrB (Acriflavine resistance protein), as well as cells lacking the outer membrane factor (OMF) TolC (Tolerance to colicins). Consistent with the ATPase function of VcaM we found it to be susceptible to sodium orthovanadate (NaOV), however, we also found a clear dependency of VcaM function on TolC. Inhibitors targeting secondary active transporters had no effects on either VcaM-conferred resistance or Hoechst 33342 accumulation, suggesting that VcaM might be capable of engaging with the TolC-channel without periplasmic mediation by additional transporters. Our findings are indicative of VcaM being capable of a one-step substrate translocation from cytosol to extracellular space utilising the TolC-channel, making it the only multidrug ABC-transporter outside of the MacB-family with demonstrable TolC-dependency
Morphology, Mechanical Performance and Nanoindentation Behavior of Injection Molded PC/ABS-MWCNT Nanocomposites
"This is the peer reviewed version of the following article: Wegrzyn, M., Sahuquillo, O., Benedito, A., & Gimenez, E. (2015). Morphology, mechanical performance, and nanoindentation behavior of injection molded PC/ABS‐MWCNT nanocomposites. Journal of Applied Polymer Science, 132(22), which has been published in final form at https://doi.org/10.1002/app.42014. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."[EN] In this work, nanocomposites of polycarbonate/acrylonitrile-butadiene-styrene (PC/ABS) with various loads of multiwall carbon nanotubes (MWCNT) are investigated. Material is previously formed by masterbatch dilution approach and further processed by injection molding at various velocities. Microscopic characterization of nanocomposites morphology reveals stronger
dependence of MWCNT dispersion on processing parameters at higher nanofiller load. Dispersion of carbon nanotubes at various distances from the injection gate is studied by Raman spectroscopy showing lower deviation at elevated injection velocity. Nanoindentation results that are in agreement with uniaxial tensile testing show a slight decrease of nanocomposites¿ mechanical performance at 3.0 wt % MWCNT in samples injected at reduced velocity. This is explained by the increase of agglomeration behavior at these conditions.This work is funded by the European Community's Seventh Framework Program (FP7-PEOPLE-ITN-2008) within the CONTACT project Marie Curie Fellowship under grant number 238363.Wegrzyn, M.; Sahuquillo, O.; Benedito, A.; Giménez Torres, E. (2015). Morphology, Mechanical Performance and Nanoindentation Behavior of Injection Molded PC/ABS-MWCNT Nanocomposites. Journal of Applied Polymer Science. 132(22):1-8. https://doi.org/10.1002/app.42014S1813222Alig, I., Lellinger, D., Engel, M., Skipa, T., & Pötschke, P. (2008). Destruction and formation of a conductive carbon nanotube network in polymer melts: In-line experiments. Polymer, 49(7), 1902-1909. doi:10.1016/j.polymer.2008.01.073Sathyanarayana, S., Wegrzyn, M., Olowojoba, G., Benedito, A., Gimenez, E., Huebner, C., & Henning, F. (2013). Multiwalled carbon nanotubes incorporated into a miscible blend of poly(phenylenether)/polystyrene – Processing and characterization. Express Polymer Letters, 7(7), 621-635. doi:10.3144/expresspolymlett.2013.59Xiong, Z.-Y., Wang, L., Sun, Y., Guo, Z.-X., & Yu, J. (2013). Migration of MWCNTs during melt preparation of ABS/PC/MWCNT conductive composites via PC/MWCNT masterbatch approach. Polymer, 54(1), 447-455. doi:10.1016/j.polymer.2012.11.044Sun, Y., Guo, Z.-X., & Yu, J. (2010). Effect of ABS Rubber Content on the Localization of MWCNTs in PC/ABS Blends and Electrical Resistivity of the Composites. Macromolecular Materials and Engineering, 295(3), 263-268. doi:10.1002/mame.200900242Göldel, A., Kasaliwal, G. R., Pötschke, P., & Heinrich, G. (2012). The kinetics of CNT transfer between immiscible blend phases during melt mixing. Polymer, 53(2), 411-421. doi:10.1016/j.polymer.2011.11.039Tiusanen, J., Vlasveld, D., & Vuorinen, J. (2012). Review on the effects of injection moulding parameters on the electrical resistivity of carbon nanotube filled polymer parts. Composites Science and Technology, 72(14), 1741-1752. doi:10.1016/j.compscitech.2012.07.009Ma, P.-C., Siddiqui, N. A., Marom, G., & Kim, J.-K. (2010). Dispersion and functionalization of carbon nanotubes for polymer-based nanocomposites: A review. Composites Part A: Applied Science and Manufacturing, 41(10), 1345-1367. doi:10.1016/j.compositesa.2010.07.003Sathyanarayana, S., Olowojoba, G., Weiss, P., Caglar, B., Pataki, B., Mikonsaari, I., … Henning, F. (2012). Compounding of MWCNTs with PS in a Twin-Screw Extruder with Varying Process Parameters: Morphology, Interfacial Behavior, Thermal Stability, Rheology, and Volume Resistivity. Macromolecular Materials and Engineering, 298(1), 89-105. doi:10.1002/mame.201200018Pegel, S., Pötschke, P., Petzold, G., Alig, I., Dudkin, S. M., & Lellinger, D. (2008). Dispersion, agglomeration, and network formation of multiwalled carbon nanotubes in polycarbonate melts. Polymer, 49(4), 974-984. doi:10.1016/j.polymer.2007.12.024Villmow, T., Pegel, S., Pötschke, P., & Wagenknecht, U. (2008). Influence of injection molding parameters on the electrical resistivity of polycarbonate filled with multi-walled carbon nanotubes. Composites Science and Technology, 68(3-4), 777-789. doi:10.1016/j.compscitech.2007.08.031Richter, S., Saphiannikova, M., Jehnichen, D., Bierdel, M., & Heinrich, G. (2009). Experimental and theoretical studies of agglomeration effects in multi-walled carbon nanotube-polycarbonate melts. Express Polymer Letters, 3(12), 753-768. doi:10.3144/expresspolymlett.2009.94Park, D. H., Yoon, K. H., Park, Y.-B., Lee, Y. S., Lee, Y. J., & Kim, S. W. (2009). Electrical resistivity of polycarbonate/multiwalled carbon nanotube composites under varying injection molding conditions. Journal of Applied Polymer Science, 113(1), 450-455. doi:10.1002/app.29989Chandra , A. Kramschuster , A. J. Hu , X. Turng , S. 2007 2184Lellinger, D., Xu, D., Ohneiser, A., Skipa, T., & Alig, I. (2008). Influence of the injection moulding conditions on the in-line measured electrical conductivity of polymer-carbon nanotube composites. physica status solidi (b), 245(10), 2268-2271. doi:10.1002/pssb.200879619Li, S.-N., Li, B., Li, Z.-M., Fu, Q., & Shen, K.-Z. (2006). Morphological manipulation of carbon nanotube/polycarbonate/polyethylene composites by dynamic injection packing molding. Polymer, 47(13), 4497-4500. doi:10.1016/j.polymer.2006.04.051Schuh, C. A. (2006). Nanoindentation studies of materials. Materials Today, 9(5), 32-40. doi:10.1016/s1369-7021(06)71495-xOliver, W. C., & Pharr, G. M. (1992). An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments. Journal of Materials Research, 7(6), 1564-1583. doi:10.1557/jmr.1992.1564Cakmak, U. D., Schöberl, T., & Major, Z. (2011). Nanoindentation of polymers. Meccanica, 47(3), 707-718. doi:10.1007/s11012-011-9481-6VanLandingham, M. R., Villarrubia, J. S., Guthrie, W. F., & Meyers, G. F. (2001). Nanoindentation of polymers: an overview. Macromolecular Symposia, 167(1), 15-44. doi:10.1002/1521-3900(200103)167:13.0.co;2-tPharr, G. M., Strader, J. H., & Oliver, W. C. (2009). Critical issues in making small-depth mechanical property measurements by nanoindentation with continuous stiffness measurement. Journal of Materials Research, 24(3), 653-666. doi:10.1557/jmr.2009.0096Yao, C.-K., Liao, J.-D., Chung, C.-W., Sung, W.-I., & Chang, N.-J. (2012). Porous chitosan scaffold cross-linked by chemical and natural procedure applied to investigate cell regeneration. Applied Surface Science, 262, 218-221. doi:10.1016/j.apsusc.2012.05.128Sonnenfeld, A., Roth, C., Dimitrova, Z., Spillmann, A., & von Rohr, P. R. (2009). Plasma Enhanced Chemical Vapor Deposition on Particulate Solid-State Materials for Improved Powder Processing. Plasma Processes and Polymers, 6(S1), S860-S863. doi:10.1002/ppap.200932202Shokrieh, M. M., Hosseinkhani, M. R., Naimi-Jamal, M. R., & Tourani, H. (2013). Nanoindentation and nanoscratch investigations on graphene-based nanocomposites. Polymer Testing, 32(1), 45-51. doi:10.1016/j.polymertesting.2012.09.001Chakraborty, H., Sinha, A., Mukherjee, N., Ray, D., & Protim Chattopadhyay, P. (2013). A study on nanoindentation and tribological behaviour of multifunctional ZnO/PMMA nanocomposite. Materials Letters, 93, 137-140. doi:10.1016/j.matlet.2012.11.075Shen, L., Phang, I. Y., Liu, T., & Zeng, K. (2004). Nanoindentation and morphological studies on nylon 66/organoclay nanocomposites. II. Effect of strain rate. Polymer, 45(24), 8221-8229. doi:10.1016/j.polymer.2004.09.062Wegrzyn, M., Juan, S., Benedito, A., & Giménez, E. (2013). The influence of injection molding parameters on electrical properties of PC/ABS-MWCNT nanocomposites. Journal of Applied Polymer Science, 130(3), 2152-2158. doi:10.1002/app.39412Briscoe, B. J., Fiori, L., & Pelillo, E. (1998). Nano-indentation of polymeric surfaces. Journal of Physics D: Applied Physics, 31(19), 2395-2405. doi:10.1088/0022-3727/31/19/006Vega, J. F., Martínez-Salazar, J., Trujillo, M., Arnal, M. L., Müller, A. J., Bredeau, S., & Dubois, P. (2009). Rheology, Processing, Tensile Properties, and Crystallization of Polyethylene/Carbon Nanotube Nanocomposites. Macromolecules, 42(13), 4719-4727. doi:10.1021/ma900645fBokobza, L., & Zhang, J. (2012). Raman spectroscopic characterization of multiwall carbon nanotubes and of composites. Express Polymer Letters, 6(7), 601-608. doi:10.3144/expresspolymlett.2012.63Gupta, M., & Wang, K. K. (1993). Fiber orientation and mechanical properties of short-fiber-reinforced injection-molded composites: Simulated and experimental results. Polymer Composites, 14(5), 367-382. doi:10.1002/pc.750140503Abbasi, S., Carreau, P. J., & Derdouri, A. (2010). Flow induced orientation of multiwalled carbon nanotubes in polycarbonate nanocomposites: Rheology, conductivity and mechanical properties. Polymer, 51(4), 922-935. doi:10.1016/j.polymer.2009.12.041Sahin, S., & Yayla, P. (2005). Effects of testing parameters on the mechanical properties of polypropylene random copolymer. Polymer Testing, 24(5), 613-619. doi:10.1016/j.polymertesting.2005.03.002Chasiotis, I., Chen, Q., Odegard, G. M., & Gates, T. S. (2005). Structure-property relationships in polymer composites with micrometer and submicrometer graphite platelets. Experimental Mechanics, 45(6), 507-516. doi:10.1007/bf02427904Penumadu, D., Dutta, A., Pharr, G. M., & Files, B. (2003). Mechanical properties of blended single-wall carbon nanotube composites. Journal of Materials Research, 18(8), 1849-1853. doi:10.1557/jmr.2003.025
Seasonal Cholera from Multiple Small Outbreaks, Rural Bangladesh
Clinical and environmental Vibrio cholerae organisms collected from February 2004 through April 2005 were systematically isolated from 2 rural Bangladeshi locales. Their genetic relatedness was evaluated at 5 loci that contained a variable number of tandem repeats (VNTR). The observed minimal overlap in VNTR patterns between the 2 communities was consistent with sequential, small outbreaks from local sources
Land subsidence hazard in iran revealed by country-scale analysis of sentinel-1 insar
Many areas across Iran are subject to land subsidence, a sign of exceeding stress due to the over-extraction of groundwater during the past decades. This paper uses a huge dataset of Sentinel-1, acquired since 2014 in 66 image frames of 250×250km, to identify and monitor land subsidence across Iran. Using a two-step time series analysis, we first identify subsidence zones at a medium scale of 100m across the country. For the first time, our results provide a comprehensive nationwide map of subsidence in Iran and recognize its spatial distribution and magnitude. Then, in the second step of analysis, we quantify the deformation time series at the highest possible resolution to study its impact on civil infrastructure. The results spots the hazard posed by land subsidence to different infrastructure. Examples of road and railways affected by land subsidence hazard in Tehran and Mashhad, two of the most populated cities in Iran, are presented in this study
Chip-to-chip quantum teleportation and multi-photon entanglement in silicon
Exploiting semiconductor fabrication techniques, natural carriers of quantum
information such as atoms, electrons, and photons can be embedded in scalable
integrated devices. Integrated optics provides a versatile platform for
large-scale quantum information processing and transceiving with photons.
Scaling up the integrated devices for quantum applications requires
highperformance single-photon generation and photonic qubit-qubit entangling
operations. However, previous demonstrations report major challenges in
producing multiple bright, pure and identical single-photons, and entangling
multiple photonic qubits with high fidelity. Another notable challenge is to
noiselessly interface multiphoton sources and multiqubit operators in a single
device. Here we demonstrate on-chip genuine multipartite entanglement and
quantum teleportation in silicon, by coherently controlling an integrated
network of microresonator nonlinear single-photon sources and linear-optic
multiqubit entangling circuits. The microresonators are engineered to locally
enhance the nonlinearity, producing multiple frequencyuncorrelated and
indistinguishable single-photons, without requiring any spectral filtering. The
multiqubit states are processed in a programmable linear circuit facilitating
Bell-projection and fusion operation in a measurement-based manner. We
benchmark key functionalities, such as intra-/inter-chip teleportation of
quantum states, and generation of four-photon Greenberger-HorneZeilinger
entangled states. The production, control, and transceiving of states are all
achieved in micrometer-scale silicon chips, fabricated by complementary
metal-oxide-semiconductor processes. Our work lays the groundwork for scalable
on-chip multiphoton technologies for quantum computing and communication
Exploring cloud-based platforms for rapid insar time series analysis
The idea of near real-time deformation analysis using Synthetic Aperture Radar (SAR) data as a response to natural and anthropogenic disasters has been an interesting topic in the last years. A major limiting factor for this purpose has been the non-availability of both spatially and temporally homogeneous SAR datasets. This has now been resolved thanks to the SAR data provided by the Sentinel-1A/B missions, freely available at a global scale via the Copernicus program of the European Space Agency (ESA). Efficient InSAR analysis in the era of Sentinel demands working with cloud-based platforms to tackle problems posed by large volumes of data. In this study, we explore a variety of existing cloud-based platforms for Multioral Interferometric SAR (MTI) analysis and discuss their opportunities and limitations
Meta-analysis of genome-wide association studies of asthma in ethnically diverse North American populations.
Asthma is a common disease with a complex risk architecture including both genetic and environmental factors. We performed a meta-analysis of North American genome-wide association studies of asthma in 5,416 individuals with asthma (cases) including individuals of European American, African American or African Caribbean, and Latino ancestry, with replication in an additional 12,649 individuals from the same ethnic groups. We identified five susceptibility loci. Four were at previously reported loci on 17q21, near IL1RL1, TSLP and IL33, but we report for the first time, to our knowledge, that these loci are associated with asthma risk in three ethnic groups. In addition, we identified a new asthma susceptibility locus at PYHIN1, with the association being specific to individuals of African descent (P = 3.9 × 10(-9)). These results suggest that some asthma susceptibility loci are robust to differences in ancestry when sufficiently large samples sizes are investigated, and that ancestry-specific associations also contribute to the complex genetic architecture of asthma
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