Tank Car Top Fittings Protection: Evaluation of Derailment Failure Risks — A Conceptual Study

2016 ◽  
Author(s):  
Barbara Di Bacco ◽  
Christopher Kirney ◽  
Anand Prabhakaran ◽  
Graydon F. Booth ◽  
Florentina M. Gantoi ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Conceptual Development ◽  
Ground Surface ◽  
Protective Structure ◽  
Damage And Failure ◽  
Structural Capacity ◽  
Velocity Spectra ◽  
Conceptual Study ◽  
Future Work ◽  
The Impact

Top fittings devices on tank cars are subject to damage and failure under derailment conditions, potentially leading to the release of hazardous lading. This paper describes the conceptual development of an objective methodology for evaluating the risk of fittings protection failure and the potential reduction in that risk when mitigating strategies such as improved fittings protective structure are deployed. The methodology captures several key elements that affect fittings survival, including: the speed of derailment initiation, the impact velocity/force spectrum experienced by the fittings protective structure during the event, the strength/structural capacity of the protective structure, and the rigidity of the ground surface. Detailed finite element modeling efforts were employed to capture derailment dynamics and corresponding impact velocity spectra, as well as the strength of multiple protective designs. Future work, including validation, is planned to extend the concept into a detailed methodology.

scholarly journals Static and Dynamic Four-Point Flexural Tests of Concrete Beams with Variation in Concrete Quality, Reinforcement Properties and Impact Velocity

2021 ◽  
Vol 65 (2) ◽  
pp. 19-38
Author(s):  
Viktor Peterson ◽  
Anders Ansell
Keyword(s):  
Plastic Strain ◽  
Impact Velocity ◽  
Strain Distribution ◽  
Concrete Beams ◽  
Numerical Models ◽  
Reinforced Concrete Beams ◽  
Concrete Quality ◽  
Flexural Tests ◽  
Future Work ◽  
The Impact

Abstract This paper discusses the results from three experimental test series previously conducted. The tests consist of quasi-static monotonic and dynamic four-point flexural tests on reinforced concrete beams. The effect of varying material and load parameters on the plastic strain distribution and energy absorbed by the reinforcement is discussed. The main findings are the significant effect of the post-elastic region of the steel reinforcement and the impact velocity during dynamic loading. The results will be used to validate and construct numerical models in future work, where the findings presented can be investigated further.

The Impact of BRICS in Reconstructing the International Order

2020 ◽  
pp. 87
Author(s):  
Tareq Mohammed Dhannoon AL Taie
Keyword(s):  
International System ◽  
Political Influence ◽  
Active Role ◽  
International Order ◽  
First Century ◽  
International Affairs ◽  
Strategic Action ◽  
Brics Countries ◽  
Future Work ◽  
The Impact

The BRICS countries have a historical aspiration for global leadership, especially Russia and China, and other countries trying to have a position in the pyramid of international powers in the twenty-first century, especially Brazil, India and South Africa, they worked to unify their efforts, in order to achieve integration in the strategic action, activate its role in International affairs, ending American domination , and restructuring an international system that have an active role in its interactions.       The research hypothesis is based on the idea that the BRICS group, despite the nature of its economic composition and its long-term goals, but its political influence as a bloc, is greater than the proportion of its economic influence in restructuring the new international order. The BRICS group has the capabilities to reshape the international order, but disputes among some of its members represent a challenge to its future work. Its goals will not be achieved without teamwork. Third world countries, especially those that reject unipolarism, have regarded one of the pillars supporting multi-polarity, aiming of giving them freedom of movement in international relations. The ultimate goal of the BRICS is a political nature, as economic mechanisms are used to achieve political goals.

Relay Selection-aware Non-orthogonal Multiple Access Networks: Direct and Relaying Mode

2020 ◽  
Vol 13 (3) ◽  
pp. 348-354
Author(s):  
Dinh-Thuan Do ◽  
Minh-Sang V. Nguyen
Keyword(s):  
Relay Selection ◽  
Multiple Access ◽  
Decode And Forward ◽  
Selection Scheme ◽  
Fixed Power ◽  
Transmission Quality ◽  
Improved Performance ◽  
Outage Probabilities ◽  
Future Work ◽  
The Impact

Objective: In this paper, Decode-and-Forward (DF) mode is deployed in the Relay Selection (RS) scheme to provide better performance in cooperative downlink Non-orthogonal Multiple Access (NOMA) networks. In particular, evaluation regarding the impact of the number of multiple relays on outage performance is presented. Methods: As main parameter affecting cooperative NOMA performance, we consider the scenario of the fixed power allocations and the varying number of relays. In addition, the expressions of outage probabilities are the main metric to examine separated NOMA users. By matching related results between simulation and analytical methods, the exactness of derived formula can be verified. Results: The intuitive main results show that in such cooperative NOMA networks, the higher the number of relays equipped, the better the system performance can be achieved. Conclusion: DF mode is confirmed as a reasonable selection scheme to improve the transmission quality in NOMA. In future work, we will introduce new relay selections to achieve improved performance.

scholarly journals The Effect of LiDAR Sampling Density on DTM Accuracy for Areas with Heavy Forest Cover

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 265
Author(s):  
Mihnea Cățeanu ◽  
Arcadie Ciubotaru
Keyword(s):  
Forest Cover ◽  
Initial Point ◽  
Ground Surface ◽  
Digital Terrain Model ◽  
Morphological Data ◽  
Sampling Density ◽  
Terrain Model ◽  
Digital Terrain ◽  
Point Density ◽  
The Impact

Laser scanning via LiDAR is a powerful technique for collecting data necessary for Digital Terrain Model (DTM) generation, even in densely forested areas. LiDAR observations located at the ground level can be separated from the initial point cloud and used as input for the generation of a Digital Terrain Model (DTM) via interpolation. This paper proposes a quantitative analysis of the accuracy of DTMs (and derived slope maps) obtained from LiDAR data and is focused on conditions common to most forestry activities (rough, steep terrain with forest cover). Three interpolation algorithms were tested: Inverse Distance Weighted (IDW), Natural Neighbour (NN) and Thin-Plate Spline (TPS). Research was mainly focused on the issue of point data density. To analyze its impact on the quality of ground surface modelling, the density of the filtered data set was artificially lowered (from 0.89 to 0.09 points/m2) by randomly removing point observations in 10% increments. This provides a comprehensive method of evaluating the impact of LiDAR ground point density on DTM accuracy. While the reduction of point density leads to a less accurate DTM in all cases (as expected), the exact pattern varies by algorithm. The accuracy of the LiDAR-derived DTMs is relatively good even when LiDAR sampling density is reduced to 0.40–0.50 points/m2 (50–60 % of the initial point density), as long as a suitable interpolation algorithm is used (as IDW proved to be less resilient to density reductions below approximately 0.60 points/m2). In the case of slope estimation, the pattern is relatively similar, except the difference in accuracy between IDW and the other two algorithms is even more pronounced than in the case of DTM accuracy. Based on this research, we conclude that LiDAR is an adequate method for collecting morphological data necessary for modelling the ground surface, even when the sampling density is significantly reduced.

scholarly journals A Qualitative Study of COVID-19 Distress in University Students

2021 ◽  
pp. 216769682110251
Author(s):  
Samantha G. Farris ◽  
Mindy M. Kibbey ◽  
Erick J. Fedorenko ◽  
Angelo M. DiBello
Keyword(s):  
University Students ◽  
Undergraduate Students ◽  
Mental Health Problems ◽  
Financial Strain ◽  
Public Response ◽  
Viral Spread ◽  
Future Work ◽  
The Impact ◽  
Viral Outbreak ◽  
Selection Of

The psychological effect of the pandemic and measures taken in response to control viral spread are not yet well understood in university students; in-depth qualitative analysis can provide nuanced information about the young adult distress experience. Undergraduate students ( N = 624) in an early US outbreak “hotspot” completed an online narrative writing about the impact and distress experienced due to the COVID-19 pandemic. Data were collected April-May 2020. A random selection of 50 cases were sampled for thematic analysis. Nine themes were identified: viral outbreak distress, fear of virus contraction/transmission, proximity to virus, dissatisfaction with public response, physical distancing distress, social distancing distress, academic and school-related distress, disruptive changes in health behavior and routines, financial strain and unemployment, worsening of pre-existing mental health problems, and social referencing that minimizes distress. Future work is needed to understand the persistence of the distress, in addition to developing methods for assessment, monitoring, and mitigation of the distress.

scholarly journals Air mediates the impact of a compliant hemisphere on a rigid smooth surface

Soft Matter ◽  
2021 ◽  
Author(s):  
Siqi Zheng ◽  
Sam Dillavou ◽  
John M. Kolinski
Keyword(s):  
Elastic Body ◽  
Elastic Properties ◽  
Impact Velocity ◽  
Solid Surface ◽  
High Speed ◽  
Smooth Surface ◽  
High Speed Imaging ◽  
The Impact ◽  
Rigid Smooth

When a soft elastic body impacts upon a smooth solid surface, the intervening air fails to drain, deforming the impactor. High-speed imaging with the VFT reveal rich dynamics and sensitivity to the impactor's elastic properties and the impact velocity.

scholarly journals Impact of a Series of Educational Talks Taught by Health Professionals to Promote Healthy Snack Choices among Children

Children ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 203
Author(s):  
Víctor Arufe Giráldez ◽  
Javier Puñal Abelenda ◽  
Rubén Navarro-Patón ◽  
Alberto Sanmiguel-Rodríguez
Keyword(s):  
Nutritional Quality ◽  
Positive Impact ◽  
Total Sample ◽  
Overweight And Obesity ◽  
Healthy Habits ◽  
Quasi Experimental ◽  
Nutrition And Dietetics ◽  
Future Work ◽  
The Impact

Background: One of the great challenges facing today’s society is the need to combat overweight and obesity in schoolchildren. This study aimed to analyze the impact of a cycle of didactic talks—given to families by a specialist in pediatrics, a specialist in nutrition and dietetics and a specialist in physical exercise—on childrens’ snack choices and nutrition quality. Methods: A longitudinal, quasi-experimental and quantitative investigation was designed, working with a total sample of 50 students divided into control and experimental groups. The nutritional quality of daily snacks was recorded during the month before and the month after the cycle of talks given by health experts. Results: An increase in the nutritional quality of the snacks was observed in the days after the talk—but, after a week, values returned to normal. Conclusions: The giving of educational talks to promote healthy habits may have a positive impact on the nutritional quality of school snacks in the days immediately following the talks. However, some forgetfulness was detected over time, which reduced the nutritional quality of the snacks once more. For future work, it is recommended that researchers measure the impact produced by giving regular talks.

scholarly journals A smart passive MR damper with a hybrid powering system for impact mitigation: An experimental study

2021 ◽  
pp. 1045389X2098808
Author(s):  
S. Jin ◽  
L. Deng ◽  
J. Yang ◽  
S. Sun ◽  
D. Ning ◽  
...  
Keyword(s):  
Impact Velocity ◽  
Mr Damper ◽  
Damping Force ◽  
Softening Effect ◽  
Impact Speed ◽  
Impact Mitigation ◽  
Passive Damper ◽  
Comparison Results ◽  
Wide Range ◽  
The Impact

This paper presents a smart passive MR damper with fast-responsive characteristics for impact mitigation. The hybrid powering system of the MR damper, composed of batteries and self-powering component, enables the damping of the MR damper to be negatively proportional to the impact velocity, which is called rate-dependent softening effect. This effect can keep the damping force as the maximum allowable constant force under different impact speed and thus improve the efficiency of the shock energy mitigation. The structure, prototype and working principle of the new MR damper are presented firstly. Then a vibration platform was used to characterize the dynamic property and the self-powering capability of the new MR damper. The impact mitigation performance of the new MR damper was evaluated using a drop hammer and compared with a passive damper. The comparison results demonstrate that the damping force generated by the new MR damper can be constant over a large range of impact velocity while the passive damper cannot. The special characteristics of the new MR damper can improve its energy dissipation efficiency over a wide range of impact speed and keep occupants and mechanical structures safe.

Sign in / Sign up

Export Citation Format

Share Document