Search results for "Rail"
showing 10 items of 699 documents
Laser-Generated Acoustic Signal Interaction with Surface Flaws on Rail Wheels
2005
Long- and short-range acoustic-signal interaction with surface-breaking cracks and geometric boundaries of the rail-wheel tread area are presented in this article. Ultrasonic signals are generated using a laser-line source of varying length and distance from a crack and are detected with a 1-MHz contact transducer to map the sound field behind the crack in the near, intermediate, and far fields of the insonified region. The factors that affect the behavior of a laser-generated surface acoustic wave propagating along the tread area of a rail wheel are discussed. A signal normalization method is proposed to help in sensing the presence of a crack from the transmitted signal unaffected by the …
The Insolvency of Cryptocurrency Exchanges: Lessons from the BitGrail Case — Reification of Coins, Pari Passu Ranking, and Nominalism
2019
This paper deals with a recent trend in insolvency of cryptocurrency platforms; comments on the BitGrail case (Court of Florence 17/2019, 21 January 2019) and argues that this decision balances the need to grant legal protection to the injured users and the need to prevent them from having the status of owners, jumping the queue and getting a head start over the other creditors of the platform.
Ultrasonic Guided Waves-Based Monitoring of Rail Head: Laboratory and Field Tests
2010
Recent train accidents have reaffirmed the need for developing a rail defect detection system more effective than that currently used. One of the most promising techniques in rail inspection is the use of ultrasonic guided waves and noncontact probes. A rail inspection prototype based on these concepts and devoted to the automatic damage detection of defects in rail head is the focus of this paper. The prototype includes an algorithm based on wavelet transform and outlier analysis. The discrete wavelet transform is utilized to denoise ultrasonic signals and to generate a set of relevant damage sensitive data. These data are combined into a damage index vector fed to an unsupervised learning…
Digital signal processing for rail monitoring by means of ultrasonic guided waves
2007
Recent train accidents have reaffirmed the need for developing rail defect detection systems that are more effective than those used today. One of the recent developments in rail inspection is the use of ultrasonic guided waves (UGWs) and non-contact probing techniques to target transverse-type defects. Besides the obvious advantages of non-contact probing, that include robustness and a potential for large inspection speed, such a system can theoretically detect transverse defects under horizontal shelling or head checks. This paper demonstrates the effectiveness of digital signal processing to enhance the damage detection sensitivity of the non-contact system. The method proposed here comb…
Letter Position Coding Across Modalities: The Case of Braille Readers
2012
BackgroundThe question of how the brain encodes letter position in written words has attracted increasing attention in recent years. A number of models have recently been proposed to accommodate the fact that transposed-letter stimuli like jugde or caniso are perceptually very close to their base words.MethodologyHere we examined how letter position coding is attained in the tactile modality via Braille reading. The idea is that Braille word recognition may provide more serial processing than the visual modality, and this may produce differences in the input coding schemes employed to encode letters in written words. To that end, we conducted a lexical decision experiment with adult Braille…
The chemistry of competition: exploitation of heterospecific cues depends on the dominance rank in the community
2014
Interspecific competition is an important ecological mechanism shaping the traits of the interacting species and structuring their communities. Less competitive species benefit from evading direct encounters with aggressive dominants, whereas dominant species could use cues left by subordinates to steal their resources or to chase them off. Here, we studied competitive interactions among five common and syntopic ant species in Central Europe (Formica polyctena, Formica rufibarbis, Lasius niger, Myrmica rubra and Tetramorium caespitum) and investigated their ability to react to heterospecific chemical cues. Using aggression assays, we established a clear dominance hierarchy of these species,…
Cognitive Frailty: An Update
2021
This review article provides an update of the empirical research on cognitive fragility conducted in the last four years. The studies retrieved were classified in four different categories. The first category includes articles relating cognitive frailty to cognitive reserve and which continue to highlight the importance of educational level. The second category includes recent research on cognitive fragility biomarkers, involving neuroimaging, metabolism and, in a novel way, microbiota. The third category includes research on how cognitive frailty is related to motor development and physical functioning, exploring e.g. the use of technology to study motor markers of cognitive frailty. Final…
Tarifa attālumi: spēkā ar 1938. gada 1. maiju
1938
Izdevums vilcienu konduktoru dienesta vajadzībām
Отчетъ завѣдывающаго работами о результатахъ его наблюденій при изученіи желѣзныхъ дорогъ Западной Европы съ предложеніемъ возможнаго переустройства …
1903
Содержание: Предисловіе ; Отдѣлъ I-й. Краткий обзоръ Ж. д. узловъ западной Европы : [Берлинъ. Вѣна. Парижъ. Дрезденъ. Франкфуртъ на Майнѣ. Кельнъ. Гамбургъ] ; Отдѣлъ II-й. Выводъ основныхъ положеній ; Отдѣлъ III-й. Обзоръ основныхъ положеній въ каждомъ изъ узловъ западной Европы ; Отдѣлъ IV-й. Возможное примѣнение основныхъ положеній къ Рижскому узлу ; Отдѣлъ V-й. Заключеніе ; Схема относительной зависимости частей Рижскаго ж. д. узла.
Eröffnungsfeier des Passagierverkehrs in Riga vom neuen Bahnhof "Riga-Glawnaja" (Haupt-Bahnhof) über die neue Düna-Eisenbahnbrücke
1914
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