Probabilistic Risk Analysis of Broken Rail-Caused Train Derailments

2020 ◽  
Author(s):  
Zhipeng Zhang ◽  
Kang Zhou ◽  
Xiang Liu
Keyword(s):  
Risk Model ◽  
Quantitative Estimation ◽  
Low Frequency ◽  
Machine Learning Techniques ◽  
Affecting Factors ◽  
Efficient Manner ◽  
Major Activity ◽  
Long Time ◽  
Cost Efficient ◽  
Railroad Company

Abstract Broken-rail prevention and risk management have been being a major activity for a long time for the railroad industry. The major objective of this research is to evaluate and analyze the broken rail-caused derailment risk using Artificial Intelligence (AI) approaches. The risk model is primarily built upon 1) broken rail probability; 2) probability of broken-rail derailment given a broken rail; and 3) derailment severity, measured by the number of cars derailed. The train derailment risk accounts for derailment probability and derailment consequences simultaneously. Due to the low frequency of broken-rail derailments, it is desirable to estimate the probability of broken rail-caused derailments through the broken rail occurrence. The estimation of the probability of broken rail-caused derailment includes the conditional probability of derailment given broken rail occurrence and the probability of broken rail occurrence. More specially, the probability of broken-rail derailment given a broken rail can be estimated by the statistical relationship between broken-rail derailment and broken rail, given specific variables (e.g., track curvature, signal condition, and annual traffic). The probability of broken rails can be estimated using machine learning techniques based on railroad big data, including maintenance, track layout, traffic and historical inspection records. In terms of derailment consequence, it is defined as the number of cars (both loaded and empty) derailed per derailment that would be estimated based on potentially affecting factors, such as train length, train speed, and train tonnage. The quantitative estimation and analysis of broken rail-caused derailments are based upon the historical records from one Class I railroad company from 2012 to 2016, covering over 20,000 track miles on mainlines. The developed integrated risk model is able to contribute to the prediction of location-centric broken rail-caused derailment risk. Ultimately, the identification of high-risk locations can ultimately aid the railroads to mitigate broken rail risk in a cost-efficient manner and improve railroad safety.

scholarly journals Electromagnetic power of lightning superbolts from Earth to space

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
J.-F. Ripoll ◽  
T. Farges ◽  
D. M. Malaspina ◽  
G. S. Cunningham ◽  
E. H. Lay ◽  
...  
Keyword(s):  
Low Frequency ◽  
Optical Emission ◽  
High Energy ◽  
Very Low Frequency ◽  
Electromagnetic Power ◽  
Power Spectral ◽  
High Energy Tail ◽  
Van Allen Probes ◽  
Long Time ◽  
Low Frequency Waves

AbstractLightning superbolts are the most powerful and rare lightning events with intense optical emission, first identified from space. Superbolt events occurred in 2010-2018 could be localized by extracting the high energy tail of the lightning stroke signals measured by the very low frequency ground stations of the World-Wide Lightning Location Network. Here, we report electromagnetic observations of superbolts from space using Van Allen Probes satellite measurements, and ground measurements, and with two events measured both from ground and space. From burst-triggered measurements, we compute electric and magnetic power spectral density for very low frequency waves driven by superbolts, both on Earth and transmitted into space, demonstrating that superbolts transmit 10-1000 times more powerful very low frequency waves into space than typical strokes and revealing that their extreme nature is observed in space. We find several properties of superbolts that notably differ from most lightning flashes; a more symmetric first ground-wave peak due to a longer rise time, larger peak current, weaker decay of electromagnetic power density in space with distance, and a power mostly confined in the very low frequency range. Their signal is absent in space during day times and is received with a long-time delay on the Van Allen Probes. These results have implications for our understanding of lightning and superbolts, for ionosphere-magnetosphere wave transmission, wave propagation in space, and remote sensing of extreme events.

Investigation on the Machining of Thick Diamond Films by EDM Together with Mechanical Polishing

2007 ◽  
Vol 24-25 ◽  
pp. 377-382
Author(s):  
Rong Fa Chen ◽  
Dun Wen Zuo ◽  
Yu Li Sun ◽  
Wen Zhuang Lu ◽  
D.S. Li ◽  
...  
Keyword(s):  
Diamond Films ◽  
Polycrystalline Diamond ◽  
Mechanical Polishing ◽  
Polishing Process ◽  
Two Stage ◽  
Efficient Manner ◽  
Raman Scattering Spectroscopy ◽  
Electro Discharge Machining ◽  
Diamond Polishing ◽  
Cost Efficient

Although research on various diamond polishing techniques has been carried for years, some issues still need to be examined in order to facilitate application on large areas in a cost-efficient manner. A compositive technique for machining efficiently thick diamond films prepared by DC plasma arc jet is reported in the present paper. A two-stage polishing was applied on thick polycrystalline diamond films, by employing first electro-discharge machining (EDM) for rough polishing and subsequently mechanical polishing for finishing operations. Experimental results obtained clearly indicate the applicability of the proposed two-stage technique for fabricating transparent diamond films that can be used for the production of X-ray windows. Appropriate etching with EDM is an effective pretreatment method for enhancing the efficiency of rough polishing process in mechanical polishing of thick diamond film. The machined surfaces of diamond films are studied by Scanning Electron Microscope (SEM) and Raman Scattering Spectroscopy (Raman).

Achieving Indonesian Oil and Gas production to 1 million barrels per day by 2030 using Nanoflooding as Novel EOR Method: Dream vs. Reality

2021 ◽  
Author(s):  
L. Hendraningrat
Keyword(s):  
Oil Recovery ◽  
Cost Efficiency ◽  
Oil And Gas ◽  
Gas Production ◽  
Oil Price ◽  
Efficient Manner ◽  
Oil And Gas Production ◽  
Cost Efficient ◽  
Nano Size ◽  
Production Target

In low oil price environments, conducting affordable enhanced oil recovery (EOR) projects can be very challenging. One item of interest for successful future EOR should be in how produced fluids are treated and how to achieve cost-efficiency. Nanoflooding, is an emerging EOR technique, which has attracted deployment in recent years. Meanwhile, Indonesia continues to progress towards the national oil and gas production target of one million barrels per day by 2030. This paper presents the observation of opportunities and challenges of using nanoflooding to enable oil and gas production in Indonesia to achieve its desired targets. The study began by mapping the pain points in major oilfields in Indonesia. We observed and discussed the advantage and limitation of traditional mature EOR techniques, status, and ongoing application of EOR in Indonesia. Then, we briefly explained the main reasons why nanoflooding can be considered for future implementation in accelerating oil production in Indonesia, including a discussion about a successful pilot test. As an emerging EOR technique, nanoflooding can be considered as a cost-efficient technique. Silica-based nanofluid can be accessed in a cost-efficient manner and can be executed from an implementation standpoint considering surface facilities. The mechanism that is introduced can help to displace incremental oil more effectively since it can go inside pore throats due to the nano-size. We observed several recognized benefits and challenges to deploy nanoflooding in Indonesia. Based on this study, nanoflooding is very attractive and has potential to be implemented.

Interaction of Point Defects in Ice

1978 ◽  
Vol 21 (85) ◽  
pp. 115-122
Author(s):  
J. H. Bilgram ◽  
H. Gränicher
Keyword(s):  
Experimental Data ◽  
Dielectric Properties ◽  
Temperature Dependence ◽  
Point Defects ◽  
Low Frequency ◽  
Defect Concentration ◽  
Dielectric Measurements ◽  
Long Time ◽  
Nmr Techniques ◽  
Bjerrum Defect

AbstractThe interaction of point detects in ice has been neglected for a long time. Experimental data obtained from dielectric measurements on HF-doped crystals stimulated a new evaluation of the possibility of an interaction between Bjerrum defects and ions. In a previous paper it has been shown that this leads us to assume the existence of aggregates of Bjerrum defects and ions. In this paper these aggregates and Bjerrum defects are used to explain the dielectric properties of ice, especially the temperature dependence of the product of the high and low frequency conductivity σ0σ∞.The interaction of Bjerrum defects and impurity molecules leads to a dependence of the concentration of frenkel pairs on Bjerrum-defect concentration. At HF concentrations above the native Bjerrum-defect concentration the formation of a Frenkel pair is enhanced. This leads to the fast out-diffusion which has been studied in highly doped crystals by means of NMR techniques.

Prognostic relevance of anamnestic and diagnostic parameters in low-frequency hearing impairment

2006 ◽  
Vol 120 (8) ◽  
pp. 613-618 ◽  
Author(s):  
W Maier ◽  
J Schipper
Keyword(s):  
Prognostic Factor ◽  
Hearing Impairment ◽  
Hearing Threshold ◽  
Low Frequency ◽  
Prognostic Indicators ◽  
Infusion Therapy ◽  
Prognostic Relevance ◽  
Long Time ◽  
Dehydration Therapy

Low-frequency hearing impairment (LFHI) is mainly attributed to endolymphatic hydrops and has a great variety of possible outcomes. At present, no conservative therapeutic regimen has proven to be ‘gold-standard’, and information about the prognostic indicators of LFHI is scarce.In a retrospective investigation, we evaluated the records of 90 patients who had been treated with infusions improving blood perfusion. In patients lacking complete remission, dehydration infusion therapy was added. We also undertook audiometric follow up. We calculated the outcomes after infusion therapy, dehydration therapy and after long-time hearing follow up, and we determined the prognostic relevance of several parameters of anamnesis and clinical examination to outcomes, for both therapeutic interventions and long-time hearing.The prognosis of LFHI was significantly correlated to certain anamnestic and clinical parameters; a short duration of the disease, lack of vertigo and female gender implied a better outcome. The pretherapeutic hearing threshold was an important prognostic factor; the outcome was significantly worse in patients with distinct hearing impairment in low or high frequencies, compared with that in patients with little hearing loss. Whereas vertigo was a negative prognostic factor, the results of quantitative vestibular testing were irrelevant to the outcome. The glycerol test failed to predict the effectiveness of dehydration therapy and lacked any value in predicting prognosis.These results allow the clinician to focus the anamnesis and diagnostic examination on prognostically relevant parameters, thus enabling a better estimation of the long-term disease course and improved counselling of patients. Furthermore, these results help to distinguish valuable from irrelevant diagnostic procedures.

scholarly journals Rethinking the Role of Lawyers for Children : Child Representation in Canadian Family Relationship Cases

2019 ◽  
Vol 59 (4) ◽  
pp. 787-829
Author(s):  
Nicholas Bala ◽  
Rachel Birnbaum
Keyword(s):  
Family Relationship ◽  
Older Children ◽  
Efficient Manner ◽  
Child Report ◽  
Significant Evidence ◽  
The Family ◽  
Justice Process ◽  
Cost Efficient ◽  
Comprehensive Programs

This article examines various methods for involving children in family and child welfare proceedings, surveys varying approaches in different Canadian jurisdictions to the appointment of counsel for children in these cases, and explores the controversies about the role of counsel for children. While child representation is becoming common, in most provinces it is usually limited to welfare proceedings involving older children. All jurisdictions, however, have some provisions to allow for child participation in family relationship cases. Governments and law societies in Canada should develop more coherent and comprehensive programs and policies to ensure that the views of children are considered in the family justice process in a child-focused and cost-efficient manner. There needs to be more recognition of the role of lawyers in facilitating settlement. Appointment of counsel is, however, not always the best way to involve children ; if the child is willing to share views, in some cases this may be better done by a judicial interview, a Views of the Child Report or an assessment. There should be a presumption that counsel will be an instructional advocate, but if a child lacks the capacity or willingness to instruct counsel, counsel should be an advocate for the rights and interests of the child. Regardless of the role adopted, counsel for a child also has responsibility for introducing significant evidence not otherwise before the court.

scholarly journals Effect of randomly distributed polypropylene fiber reinforcement on the shear behavior of sandy soil

2019 ◽  
Vol 41 (3) ◽  
pp. 151-159
Author(s):  
Mehdi Missoum Benziane ◽  
Noureddine Della ◽  
Sidali Denine ◽  
Sedat Sert ◽  
Said Nouri
Keyword(s):  
Sandy Soil ◽  
Mechanical Characteristics ◽  
Polypropylene Fiber ◽  
Fiber Content ◽  
Polypropylene Fibers ◽  
Normal Stresses ◽  
Efficient Manner ◽  
Cost Efficient ◽  
Shear Box ◽  
Loose Medium

AbstractThe inclusions of geosynthetic materials (fibers, geomembranes and geotextiles) is a new improvement technique that ensures uniformity in the soil during construction. The use of tension resisting discreet inclusions like polypropylene fibers has attracted a significant amount of attention these past years in the improvement of soil performance in a cost-efficient manner. A series of direct shear box tests were conducted on unreinforced and reinforced Chlef sand with different contents of fibers (0, 0.25, 0.5 and0.75%) in order to study the mechanical behavior of sand reinforced with polypropylene fibers. Samples were prepared at three different relative densities 30%, 50% and 80% representing loose, medium dense and dense states,respectively, and performed at normal stresses of 50, 100 and 200 kPa. The experimental results show that the mechanical characteristics are improved with the addition of polypropylene fibers. The inclusion of randomly distributed fibers has a significant effect on the shear strength and dilation of sandy soil. The increase in strength is a function of fiber content, where it has been shown that the mechanical characteristics improve with the increase in fiber content up to 0.75%, this improvement is more significant at a higher normal stress and relative density.

Starting from Year One: The Politics of Health in Nicaragua

1980 ◽  
Vol 10 (4) ◽  
pp. 647-656 ◽  
Author(s):  
José Carlos Escudero
Keyword(s):  
Public Health ◽  
Vital Statistics ◽  
Medical System ◽  
Efficient Manner ◽  
Popular Participation ◽  
Mortality And Morbidity ◽  
Sandinista Revolution ◽  
Cost Efficient ◽  
Health Situation ◽  
And Control

The triumphant Sandinista revolution inherited a health situation characterized by high mortality, low life expectancy, widespread malnutrition, and a medical system limited in scope. The extent of these problems can only be estimated as a result of the somocista government's failure to develop an accurate system of vital statistics. While there are many options available for rapidly decreasing the high levels of mortality and morbidity in Nicaragua, the revolutionary government has chosen a strategy which fuses public health and politics. A health network based on popular participation and control is being formed which should not only decrease the high rates of malnutrition and infectious diseases in a cost-efficient manner, but should increase the strength of the revolution as well.

scholarly journals Low-frequency unsteadiness in the wake of a normal flat plate

1998 ◽  
Vol 370 ◽  
pp. 101-147 ◽  
Author(s):  
F. M. NAJJAR ◽  
S. BALACHANDAR
Keyword(s):  
Shear Layer ◽  
Flat Plate ◽  
Free Stream ◽  
Low Frequency ◽  
Separated Flow ◽  
Phase Mismatch ◽  
Streamwise Vortices ◽  
Long Time ◽  
Drag And Lift ◽  
High Degree

The separated flow past a zero-thickness flat plate held normal to a free stream at Re=250 has been investigated through numerical experiments. The long-time signatures of the drag and lift coefficients clearly capture a low-frequency unsteadiness with a period of approximately 10 times the primary shedding period. The amplitude and frequency of drag and lift variations during the shedding process are strongly modulated by the low frequency. A physical interpretation of the low-frequency behaviour is that the flow gradually varies between two different regimes: a regime H of high mean drag and a regime L of low mean drag. It is observed that in regime H the shear layer rolls up closer to the plate to form coherent spanwise vortices, while in regime L the shear layer extends farther downstream and the rolled-up Kármán vortices are less coherent. In the high-drag regime three-dimensionality is characterized by coherent Kármán vortices and reasonably well-organized streamwise vortices connecting the Kármán vortices. With a non-dimensional spanwise wavelength of about 1.2, the three-dimensionality in this regime is reminiscent of mode-B three-dimensionality. It is observed that the high degree of spanwise coherence that exists in regime H breaks down in regime L. Based on detailed numerical flow visualization we conjecture that the formation of streamwise and spanwise vortices is not in perfect synchronization and that the low-frequency unsteadiness is the result of this imbalance (or phase mismatch).

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