Article
Engineering, Electrical & Electronic
Zhaorui Zang, Ashraf Uz Zaman, Jian Yang
Summary: A single layer 77 GHz dual circularly polarized antenna array based on ridge gap waveguides (RGWs) technology is proposed in this paper. The experimental results demonstrate good agreement with simulations, indicating that the antenna has great potential for applications in automotive radars.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2022)
Article
Environmental Sciences
Jason W. Kean, Dennis M. Staley
Summary: Southern California has a long history of damaging debris flows after wildfires, but forecasts of the frequency and magnitude of postfire debris flows are not as readily available as they are for earthquakes. Research shows that small debris flows can be expected almost every year, while major debris flows capable of damaging 40 or more structures have a recurrence interval between 10 and 13 years.
Article
Ecology
Alexandra D. Syphard, Teresa J. Brennan, Heather Rustigian-Romsos, Jon E. Keeley
Summary: One consequence of global change is the possibility of vegetation type conversion, such as the conversion from woody shrublands to grasslands in Southern California. The relative importance of short-interval fires in driving this conversion has been a subject of debate, but this study confirms that fire plays a significant role.
ECOLOGICAL APPLICATIONS
(2022)
Article
Engineering, Geological
David Bernard, Emily Trousil, Paul Santi
Summary: Prediction of possible inundation areas is critical for debris-flow hazard management and was achieved in this research by developing runout parameters specific to post-wildfire debris flows. Using data from flows triggered by a storm in 2003, equations were modified to best estimate post-wildfire data, providing values within certain prediction intervals. These values are expected to apply to post-wildfire debris flows in Southern California mountain ranges.
ENGINEERING GEOLOGY
(2021)
Article
Engineering, Electrical & Electronic
Sooyoung Oh, Hong Soo Park, Juntaek Oh, Sun K. Hong
Summary: Nonlinear radars can detect small targets that are difficult to detect by detecting the nonlinear responses from semiconductor junctions. In this paper, a circularly polarized dual-band shared-aperture antenna applicable to nonlinear radar is proposed, and its characteristics are demonstrated through simulation and measurement. The proposed antenna shows good circular polarization characteristics and high isolation between ports in both S-band and C-band, and its performance for nonlinear detection is verified through an experiment.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2022)
Letter
Engineering, Aerospace
Henadz Krukovich, Thomas Pratt
Summary: This paper focuses on the utilization of a dual-polarized radar system for non-contact sensing applications involving rotational motion. The polarization-centric methods are used to sense and characterize the responses from an electric motor with bearing faults and a high-velocity fan. Conventional characterizations are compared with polarization-based statistical approaches in order to explore their differences.
IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS
(2022)
Article
Engineering, Electrical & Electronic
Zhaorui Zang, Ashraf Uz Zaman, Jian Yang
Summary: This article proposes a series-fed, single-layer dual-circularly polarized slot array antenna that is fed by a stepped ridge gap waveguide (RGW) at the 77-GHz band. The antenna is capable of generating dual-circularly polarized waves, making it suitable for next-generation polarimetric radar in automotive applications. The antenna consists of eight columns of linear arrays and two feeding ports for exciting the slots. The design process and measured results are presented in this article. The measured results demonstrate that the achieved gain of the proposed antenna is above 27.3 dBi, with an axial ratio of about 2 dB over the frequency range of 76-79 GHz, exhibiting dual-CP patterns. The S-11 and S-22 values for the proposed antenna are below -10 dB, and the measured port isolation is above 17.5 dB.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Geochemistry & Geophysics
Jinglu He, Wenlong Chang, Fuping Wang, Ying Liu, Yinghua Wang, Hongwei Liu, Yinghua Li, Lei Liu
Summary: This paper proposes a new method for ship classification using dual-polarization SAR images. By extracting second-order representations and using bilinear pooling, combined with multipolarization fusion loss for model training, better classification results are achieved.
IEEE GEOSCIENCE AND REMOTE SENSING LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Marian de Orla-Barile, Forest Cannon, Nina S. Oakley, F. Martin Ralph
Summary: This study presents the first catalog of Narrow cold-frontal rainbands (NCFRs) events in Southern California during winter seasons 1995-2020. The analysis of these events provides valuable information for forecasting and improving the understanding of associated hazards. The methods established in this study can be applied to other mid-latitude regions with limited radar coverage.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Environmental Sciences
Charlie C. Schrader-Patton, Emma C. Underwood
Summary: Chaparral shrublands in Southern California play a key role in carbon sequestration, but estimations of biomass at national and regional scales often overlook shrubland biomass. A random forest model using remote sensing data was developed to predict aboveground live biomass in the region, showing improved accuracy compared to other biomass estimates. This model provides a transparent and repeatable method to track biomass recovery after management actions or disturbances.
Article
Geography, Physical
Derek J. Cheung, John R. Giardino
Summary: Wildfire incidents are increasing in frequency and magnitude in southern California. However, there is a lack of research on how ecosystems respond to changing fire regimes. This study found that post-fire debris flows will increase if fires continue to increase in size and occur on specific slopes and watersheds with certain soil burn severities.
Article
Environmental Sciences
Emanuel A. Storey, Douglas A. Stow, John F. O'Leary, Frank W. Davis, Dar A. Roberts
Summary: Regrowth after fire is critical for the persistence of chaparral shrub communities in southern California. Short-interval fires do have an impact on postfire chaparral recovery, but the impact is limited. Factors like annual precipitation, temperature, chaparral community type, and soil conditions explain a significant portion of regional variation in recovery.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Engineering, Electrical & Electronic
Ying Liu, Zhenzhen Yue, Yongtao Jia, Yunxue Xu, Quan Xue
Summary: This study presents a dual-band dual-circularly polarized magneto-electric dipole antenna array for full-duplex communication systems. The antenna can achieve LHCP at 20 GHz and RHCP at 30 GHz simultaneously with a low-loss feed network using printed ridge gap waveguide. The array consists of stacked interconnected short-circuit patches operating at different frequencies and fed by the same gap, and the performance of the antenna array was confirmed through measurements.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2021)
Article
Chemistry, Multidisciplinary
Camelia Dutta, Sonia Maniappan, Jatish Kumar
Summary: Enantiomerically pure gold nanoclusters exhibiting dual-emission of fluorescence and phosphorescence were successfully synthesized. Chiral luminescence was observed for the phosphorescence emission, leading to circularly polarized emission in both solution and solid states.
CHEMICAL COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Shuyang Yang, Zehong Yan, Peng Liu, Xi Li
Summary: A method for designing a dual-circularly polarized dual-beam transmitarray with linearly-polarized-feed is presented in this letter. The theory of decomposing linearly polarized waves into LHCP and RHCP waves is utilized to achieve independent and simultaneous control of the LHCP and RHCP phases. The designed receiver-transmitter element is utilized to realize this function, and the fabricated TA is measured to validate the simulated results.
IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS
(2022)
Article
Engineering, Geological
Jonathan A. Warrick, Andrew C. Ritchie, Kevin M. Schmidt, Mark E. Reid, Joshua Logan
Article
Geosciences, Multidisciplinary
Hui Tang, Luke A. McGuire, Francis K. Rengers, Jason W. Kean, Dennis M. Staley, Joel B. Smith
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2019)
Article
Geochemistry & Geophysics
Perach Nuriel, David M. Miller, Kevin M. Schmidt, Matthew A. Coble, Kate Maher
EARTH AND PLANETARY SCIENCE LETTERS
(2019)
Article
Geosciences, Multidisciplinary
Hui Tang, Luke A. McGuire, Francis K. Rengers, Jason W. Kean, Dennis M. Staley, Joel B. Smith
GEOPHYSICAL RESEARCH LETTERS
(2019)
Article
Geosciences, Multidisciplinary
F. K. Rengers, Jason W. Kean, Nadine G. Reitman, Joel B. Smith, Jeffrey A. Coe, Luke A. McGuire
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2020)
Article
Geosciences, Multidisciplinary
Hui Tang, Luke A. McGuire, Jason W. Kean, Joel B. Smith
GEOPHYSICAL RESEARCH LETTERS
(2020)
Article
Geosciences, Multidisciplinary
Kate E. Allstadt, Maxime Farin, Richard M. Iverson, Maciej K. Obryk, Jason W. Kean, Victor C. Tsai, Thomas D. Rapstine, Matthew Logan
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2020)
Article
Environmental Sciences
Jason W. Kean, Dennis M. Staley
Summary: Southern California has a long history of damaging debris flows after wildfires, but forecasts of the frequency and magnitude of postfire debris flows are not as readily available as they are for earthquakes. Research shows that small debris flows can be expected almost every year, while major debris flows capable of damaging 40 or more structures have a recurrence interval between 10 and 13 years.
Article
Geosciences, Multidisciplinary
Matthew A. Thomas, Francis K. Rengers, Jason W. Kean, Luke A. McGuire, Dennis M. Staley, Katherine R. Barnhart, Brian A. Ebel
Summary: This study analyzes the potential for debris flows after wildfires over time and proposes a method to improve awareness of post-wildfire debris flow hazards. The research finds that rainfall intensity and duration are closely related to the types of debris flows following wildfires, while factors such as soil moisture, rainfall climatology, and root reinforcement may also impact the probability of debris flows.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2021)
Article
Geosciences, Multidisciplinary
F. K. Rengers, Luke A. McGuire, Jason W. Kean, Dennis M. Staley, Mariana Dobre, Peter R. Robichaud, Tyson Swetnam
Summary: Post-wildfire changes in sediment redistribution were measured using terrestrial and airborne lidar in the San Gabriel Mountains in southern California. The study found that hillslope erosion dominated the overall sediment budget in the first rainy season after the wildfire, and post-wildfire erosion rates in the area were comparable to millennial time scale bedrock erosion rates.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2021)
Article
Geosciences, Multidisciplinary
K. R. Barnhart, R. P. Jones, D. L. George, B. W. McArdell, F. K. Rengers, D. M. Staley, J. W. Kean
Summary: The study focused on hazard assessment for post-wildfire debris flows in steep terrain, emphasizing the importance of reducing uncertainty in pre-event estimates of flow volume. Three debris flow runout models were tested using observations from the 2018 Montecito event, showing that model performance was most sensitive to flow volume and less sensitive to flow properties. This highlights the significance of accurately estimating flow volume for effective hazard assessment.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2021)
Article
Computer Science, Artificial Intelligence
Aniruddha Basak, Kevin M. Schmidt, Ole Jakob Mengshoel
Summary: Soil moisture is crucial for agriculture, ecosystems, and natural disasters. Existing models have poor forecasting accuracy for longer time periods. To address this issue, researchers propose two data-driven models rooted in hydrology principles and validate them using collected data. The proposed models show competitive performance and improved accuracy for soil moisture forecasting.
INTERNATIONAL JOURNAL OF DATA SCIENCE AND ANALYTICS
(2023)
Article
Astronomy & Astrophysics
Ryan P. P. Jones, Francis K. K. Rengers, Katherine R. R. Barnhart, David L. L. George, Dennis M. M. Staley, Jason W. W. Kean
Summary: Debris flow runout is a dangerous phenomenon that poses risks to human life and infrastructure. By modifying a flow model to include the effects of segregation on permeability, we found that it improved the accuracy of predicting debris flow depth and runout distance. Therefore, considering segregation is important in predicting and mitigating debris flow hazards.
EARTH AND SPACE SCIENCE
(2023)
Article
Geosciences, Multidisciplinary
Matthew A. A. Thomas, Donald N. N. Lindsay, David B. B. Cavagnaro, Jason W. W. Kean, Scott W. W. McCoy, Andrew P. P. Graber
Summary: Increased wildfire activity in the western United States has revealed gaps in understanding postfire debris-flow generation. By characterizing flows in an unstudied area, we found that short-duration, high-intensity rainfall is more likely to initiate runoff-generated debris flows compared to total storm rainfall. This finding suggests the need for a focus on localized thunderstorms or bands of intense rainfall during prolonged rainstorms for hazard assessment and warning.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Forestry
Adam G. Wells, Todd J. Hawbaker, J. Kevin Hiers, Jason Kean, Rachel A. Loehman, Paul F. Steblein
Summary: This study aimed to predict burn severity using pre-fire conditions and estimate the potential post-fire debris flow to unburned areas. Fuels, pre-fire weather, and topography were important predictors of burn severity. Predicted burn severity can be used to predict fire effects and identify potential hazards for prioritizing response and mitigation.
INTERNATIONAL JOURNAL OF WILDLAND FIRE
(2023)
