scholarly journals Inferring the Presence of Freezing Drizzle Using Archived Data from the Automated Surface Observing System (ASOS)

2020 ◽  
Vol 37 (12) ◽  
pp. 2239-2250
Author(s):  
Scott D. Landolt ◽  
Andrew Gaydos ◽  
Daniel Porter ◽  
Stephanie DiVito ◽  
Darcy Jacobson ◽  
...  
Keyword(s):  
United States ◽  
Numerical Modeling ◽  
Situational Awareness ◽  
Doppler Radar ◽  
Transportation Safety ◽  
Classification Algorithms ◽  
Current Form ◽  
Modeling Methods ◽  
Awareness Tool ◽  
Precipitation Type

AbstractIn its current form, the Automated Surface Observing System (ASOS) provides automated precipitation type reports of rain, snow, and freezing rain. Unknown precipitation can also be reported when the system recognizes precipitation is occurring but cannot classify it. A new method has been developed that can reprocess the raw ASOS 1-min-observation (OMO) data to infer the presence of freezing drizzle. This freezing drizzle derivation algorithm (FDDA) was designed to identify past freezing drizzle events that could be used for aviation product development and evaluation (e.g., Doppler radar hydrometeor classification algorithms, and improved numerical modeling methods) and impact studies that utilize archived datasets [e.g., National Transportation Safety Board (NTSB) investigations of transportation accidents in which freezing drizzle may have played a role]. Ten years of archived OMO data (2005–14) from all ASOS sites across the conterminous United States were reprocessed using the FDDA. Aviation routine weather reports (METARs) from human-augmented ASOS observations were used to evaluate and quantify the FDDA’s ability to infer freezing drizzle conditions. Advantages and drawbacks to the method are discussed. This method is not intended to be used as a real-time situational awareness tool for detecting freezing drizzle conditions at the ASOS but rather to determine periods for which freezing drizzle may have impacted transportation, with an emphasis on aviation, and to highlight the need for improved observations from the ASOS.

Diagnosing the Conditional Probability of Tornado Damage Rating Using Environmental and Radar Attributes

2015 ◽  
Vol 30 (4) ◽  
pp. 914-932 ◽  
Author(s):  
Bryan T. Smith ◽  
Richard L. Thompson ◽  
Andrew R. Dean ◽  
Patrick T. Marsh
Keyword(s):  
Conditional Probability ◽  
Situational Awareness ◽  
Rotational Velocity ◽  
Environmental Data ◽  
Doppler Data ◽  
Awareness Tool ◽  
Tornado Event ◽  
Tornado Damage ◽  
Segment Data ◽  
Horizontal Grid

Abstract Radar-identified convective modes, peak low-level rotational velocities, and near-storm environmental data were assigned to a sample of tornadoes reported in the contiguous United States during 2009–13. The tornado segment data were filtered by the maximum enhanced Fujita (EF)-scale tornado event per hour using a 40-km horizontal grid. Convective mode was assigned to each tornado event by examining full volumetric Weather Surveillance Radar-1988 Doppler data at the beginning time of each event, and 0.5° peak rotational velocity (Vrot) data were identified manually during the life span of each tornado event. Environmental information accompanied each grid-hour event, consisting primarily of supercell-related convective parameters from the hourly objective mesoscale analyses calculated and archived at the Storm Prediction Center. Results from examining environmental and radar attributes, featuring the significant tornado parameter (STP) and 0.5° peak Vrot data, suggest an increasing conditional probability for greater EF-scale damage as both STP and 0.5° peak Vrot increase, especially with supercells. Possible applications of these findings include using the conditional probability of tornado intensity as a real-time situational awareness tool.

scholarly journals Investigation of Effective Mechanical Characteristics of Nanomodified Carbon-Epoxide Composite by Numerical and Analytical Methods

2021 ◽  
Vol 12 (5) ◽  
pp. 535-541
Author(s):  
M.O. Kaptakov
Keyword(s):  
Mechanical Properties ◽  
Numerical Modeling ◽  
Fracture Surface ◽  
Mechanical Characteristics ◽  
Modeling Methods ◽  
Fullerene Soot ◽  
The Matrix ◽  
Numerical And Analytical Methods ◽  
Composite Samples

In this work, the mechanical properties of composite samples prepared using a conventional and nanomodified matrix were studied. The thickness of the monolayers in the samples was 0,2 μm. It was found in experiments, that the addition of fullerene soot as a nanomodifierled to an increase in the mechanical properties of the samples along the direction of reinforcement. At the same time, an improvement in the quality of the contact of the matrix with the fibers in the samples with the nanomodifier was observed: on the fracture surface, the nanomodified matrix envelops the fibers, while the usual matrix completely exfoliates. The obtained effects of changing the strength of composites can be associated, among other things, with a change in the level of residual stresses arising in composites during nanomodification. Analytical and numerical modeling methods are used to explain these effects.

scholarly journals Driver License Renewal Laws and Older Adults’ Daily Driving, United States, 2003–2017

2020 ◽  
Vol 75 (10) ◽  
pp. 2268-2277
Author(s):  
Sijun Shen ◽  
Kendra L Ratnapradipa ◽  
Gina C Pervall ◽  
Meredith Sweeney ◽  
Motao Zhu
Keyword(s):  
United States ◽  
Older Adults ◽  
Mandatory Reporting ◽  
Transportation Safety ◽  
Community Mobility ◽  
Males And Females ◽  
Renewal Period ◽  
Reporting Laws ◽  
License Renewal ◽  
Older Males

Abstract Objectives Around the world, aging populations pose significant concerns regarding their community mobility and transportation safety. Most previous studies in the United States have focused on the associations between driver license renewal laws and crash outcomes among older adults (65 years and older). Few studies have evaluated the impact of driver license renewal laws on older adults’ community mobility. This study aimed to identify the associations between driver license renewal laws and older males’ and females’ daily driving likelihood and duration. Method The 2003–2017 American Time Use Survey data were merged with driver license renewal legislation using ages 55–64 to control for effects of non-licensure factors (e.g., gasoline price). Weighted Poisson and linear regression models were used to estimate the associations of various driver licensure provisions with older males’ and females’ daily driving likelihood and duration. Results A shorter in-person renewal period and the presence of mandatory reporting laws for physicians were associated with a lower daily driving likelihood and shorter driving duration among females aged 75 years or older. The presence of mandatory reporting laws was also associated with reduced daily driving likelihood and duration for males aged 65–74 years. Discussion Policymakers should be aware that males and females may respond differently to older driver licensure laws, which may require distinct interventions to preserve their mobility. Future studies should consider the gender disparities when examining the association between driver licensure policies and older adults’ transportation safety and mobility.

scholarly journals Helicopter Pilots Encountering Fog: An Analysis of 109 Accidents from 1992 to 2016

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 994
Author(s):  
Alex de Voogt ◽  
Hilary Kalagher ◽  
Andrew Diamond
Keyword(s):  
United States ◽  
Decision Making ◽  
The United States ◽  
Meteorological Conditions ◽  
Transportation Safety ◽  
Online Database ◽  
Fatal Accident ◽  
Instrument Meteorological Conditions ◽  
High Prevalence ◽  
Helicopter Pilots

Helicopters have the ability to make maneuvers or precautionary off-airport landings to avoid flights into instrument meteorological conditions (IMC) such as fog. Flight accidents in which fog was encountered as well as inadvertent and intentional flights into fog were examined to understand their occurrence. A 25-year period in the United States using the National Transportation Safety Board online database was used to collect 109 accident reports of which 73 (67%) were fatal. Pilots flying intentionally into IMC were more likely to be a part of a fatal accident than those who did so inadvertently. Those pilots who were reported as being under pressure when encountering fog conditions were also more likely to be in an accident. The findings confirm a high prevalence and an added danger to intentional flights into IMC. In addition, decision-making under pressure when encountering IMC conditions is now linked to a higher proportion of fatalities, emphasizing that helicopter pilots should be made aware of these specific decision-making circumstances in their operations.

scholarly journals Review of Regulatory Emphasis on Transportation Safety in the United States, 2002-2009: Public versus Private Modes

Risk Analysis ◽  
2017 ◽  
Vol 38 (5) ◽  
pp. 1085-1101 ◽  
Author(s):  
Garrett C. Waycaster ◽  
Taiki Matsumura ◽  
Volodymyr Bilotkach ◽  
Raphael T. Haftka ◽  
Nam H. Kim
Keyword(s):  
United States ◽  
The United States ◽  
Transportation Safety ◽  
Public Versus Private

WHAT RECENT HHFT DERAILMENT FIRES TELL US

2017 ◽  
Vol 2017 (1) ◽  
pp. 2078-2095
Author(s):  
Wade A. Narin van Court ◽  
Michael S. Hildebrand ◽  
Gregory G. Noll
Keyword(s):  
United States ◽  
Crude Oil ◽  
Emergency Management ◽  
The United States ◽  
Transportation Safety ◽  
Crude Oils ◽  
Management Agency ◽  
News Reports ◽  
High Hazard ◽  
High Concentrations

ABSTRACT ID: 2017-145. In July 2016, TRC Environmental Corporation (TRC) and Hildebrand and Noll Associates, Inc. (HNA) were requested to develop planning guidance on train derailments involving large volumes/high concentrations of denatured ethanol for the Massachusetts Emergency Management Agency (MEMA). As part of this project, as well as similar projects conducted by HNA for other clients, TRC and HNA assessed current firefighting strategies for the release of ethanol and/or crude oil from High Hazard Flammable Trains (HHFT) and developed the planning assumptions necessary to prepare for these types of incidents. For these projects, studies and in-depth analyses of 27 HHFT derailments resulting in tank cars breaches that occurred in the United States and Canada involving denatured ethanol1 (ethanol) and/or crude oil2 from 2006 through 2015 were performed. The analyses were primarily based on the information from the National Transportation Safety Board (NTSB), Federal Railroad Administration (FRA), and/or Transport Canada (TC) databases, with supplemental information from news reports in some cases. The objective of these analyses was to identify key planning assumptions that would be used in developing appropriate firefighting strategies by focusing on the number and types of cars derailed, approximate train speeds at the time of the derailment, number of cars breached, amount of product released, and whether or not the released product caught fire. Additionally, the studies included obtaining and reviewing information on the properties and characteristics of ethanol, crude oils, and other Class 3 flammable materials, as well as information for railroad tank cars. Insights and understandings gained from these studies were used to further develop the firefighting strategies for HHFT derailment fires.

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