Heat island intensities over Brihan Mumbai on a cold winter and hot summer night

A mobile temperature survey of Brihan Mumbai (Greater Bombay) was undertaken on 16 January 1997 which incidentally turned out to be the coldest winter night. Heat islands were found well inside the city, away from the coastal boundary, within a distinct tongue of warm air splitting in three branches roughly along the three sub- urban railway tracks. The finding of the study were in sharp contrast with similar studies conducted during the early seventies by Daniel and Krishnamurthy (1973) and later by Mukherjee and Daniel (1976). They found a remarkable influence of sea on the horizontal temperature distribution in comparison to other factors of urbanisation and noticed the heat island over Malabar Hill, Girgaurn and Cuffe Parade area. The survey conducted after a span of twenty-two years, showed that the temperature distribution in the city and suburbs has been modified significantly and that the effect of urbanisation has overtaken the effect of maritime influence in the formation and maintenance of heat islands. Another mobile temperature survey was conducted during the early hours of 11 May 1997 on the same lines as survey conducted on 16 January 1997, to confirm the findings of earlier survey and to assess seasonal changes in the intensities of heat island. This later survey showed similar pattern of horizontal temperature distribution, though the intensity of heat island observed was only 5.5° C as compared to 11.8° C observed during winter.

Lepidium oblongum (Brassicaceae) appeared on Hungarian railways

Lepidium oblongum, of American origin is a new member of the European adventive flora, only detected in Romania so far. The first Hungarian stand was discovered in 2018, and others in 2020. Based on our studies, we detail its morphological characteristics in comparison with other Lepidium species. We present a new drawing and a table to help identify the species. Lepidium oblongum is easily identifiable by its divided (lobed or lobed-dentated) upper stem leaves. By analyzing selected climatic parameters we show that the new European habitats are found in the drier and cooler summer subtype of the humid continental climate belt. In Hungary, it spreads directly along the railways. The establishment of individual populations can be influenced by the location of cargo unloading and the movement of railway workers. Lepidium oblongum occupies gravelly, sun-exposed habitats along Hungarian railway tracks such as loading platforms, guardhouses and goods stations. Based on its high stress and climatic tolerance and initial spread-rate, it is consider to be a naturalized member of the European adventive flora, that could be potentially invasive along the European railways

Application of fuzzy mathematics for choosing maintenance intervals for non-public railway tracks

This article discusses the application of fuzzy mathematics for choosing time windows for the maintenance of non-public railway tracks. The design features of several stations and the points of junction of non-public railway tracks lead to hostile routes in the leads of the station. Moving the switching fleet through the neck creates hostility to the train route. To determine the optimal maintenance interval of non-public railway tracks, aimed at excluding hostility, it is necessary to know the throughput reserve of the railroad neck element in a certain time window. To localize the throughput reserve, it is proposed to divide the day into 30-minute intervals. This division will allow determining more accurately both the throughput reserve of the railroad neck element and the periods for servicing non-public railway tracks. The most appropriate way to calculate the throughput reserve is to use fuzzy numbers since this method allows taking into account the unequal capabilities of values within the intervals. Using the defuzzification procedure, a natural number is assigned to a given fuzzy number. After carrying out the defuzzification of the throughput reserve, the obtained values can be used to build an algorithm for selecting service intervals for non-public railway tracks.

Górski gatunek Chamaenerion palustre (Onagraceae) w Wielkopolsce

Chamaenerion palustre is distributed in Poland mostly in mountains. It was found in the lowland of Wielkopolska at two ruderal localities on rocky substrates: in 2008 in the town of Buk on a railway siding, and in 2019 in the town of Głogów near railway tracks at the train station.

EUPHORIA DAVIDII SUBILS (EUPHORBIACEAE) IN FLORA OF RAILWAY TRACKS OF DNIESTER BAY BAR

Aim. Anthropogenically transformed ecotopes act as a centre for existance of many adventive species. The distribution of North-American species Euphorbia davidii subsp. Poinsettia across various continents is often attributed to the export of grain. For some time scientists have been bringing up the issue about identification of plants E. davidii in new territories, because the species is morphologically similar to E. dentata agg. The species E. davidii is characterised by a high invasive potential, it is a neophyte. In Ukraine the species is represented by separate localities almost throughout the country. It is related to sectors of ports, railway tracks, and abandoned lands. Methods. In the year 2021, by means of route method, in sectors of railway tracks of the Dniester bay bar, between the railway stops Karolina-Buhas and Soniachna (total length is up to eight kilometers) seven localities of E. davidii were distinguished; the coordinates of the locations are listed in the publication. The examined ecotopes are characterised by a crushed stone substratum, with higher temperatures, and also by specific vibrational, insolational and hydrological modes. Results. Both inconsiderable in number of plants localities (32 exemplars) and zones, where the number of plants reaches over 2000 are represented. The extent of habitats ranges from 2 to 20 meters. The height of particular, the most developed individuals constituted 20 cm. As a rule, in the inter-rail space there is a considerably smaller number of plants, however, they are better developed, well-branched and have more inflorescences with fruits. Conclusions. A number of plants from the southern slopes of the railways is typically bigger, however, the plants on the southern slopes (in comparison with the northern ones) are worse developed, branch out less and, at the time of conducting the research were represented by a smaller number of generative individuals. In sandy sectors of the bay bar adjoining the railway tracks the plants E. davidii were almost not noticed. The individuals found in the above-mentioned sectors are characterised by stunted growth, a single stem, almost did not bloom, and did not produce seeds.

Variation of Track Response to Wheel Forces with Bogie Axle Spacing: Apparent Track Stiffness and its Influence on Dynamic Impact Forces on Railway Tracks

Track stiffness is an important parameter that affects railway track response. Axle spacing influences the response of the track to wheel forces and has an effect on track stiffness. Track response to train wheels within a bogie or between neighboring bogies vary in relation to their mutual interference, depending on the mechanical characteristics of the layers composing the track, axle spacing and bogie spacing. This interference affects the force-deflection characteristic of the railway track under a wheel. Dynamic impact forces caused by track and wheel roughness relate to track stiffness. Therefore, everything else being the same, two trains with different bogie spacing may generate different dynamic impact forces on the railway track. As a result, the accumulated damage to a railway track over time can relate not only to cumulative tonnage but also to the axle spacing of the trains operating on the railway track. Through superposition of the estimated track deflections by the beam-on-elastic-foundation theorem and looking at it from a new perspective, this paper discovers a set of relations between the variations of track stiffness with bogie axle spacing. The paper introduces a new concept of apparent track stiffness and hypothesizes that dynamic impact forces on the railway tracks relate to axle spacing. The paper then presents a numerical study and an analytical study that analyzes wheel and track interaction along stiffness transition zones for different values of axle spacing and shows that bogie axle spacing has an effect on dynamic impact forces on railway tracks.

Mathematical Description and Laboratory Study of Electrophysical Methods of Localization of Geodeformational Changes during the Control of the Railway Roadbed

Currently, the load on railway tracks is increasing due to the increase in freight traffic. Accordingly, more and more serious requirements are being imposed on the reliability of the roadbed, which means that studies of methods for monitoring the integrity of the railway roadbed are relevant. The article provides a mathematical substantiation of the possibility of using seismoelectric and phasemetric methods of geoelectric control of the roadbed of railway tracks in order to identify defects and deformations at an early stage of their occurrence. The methods of laboratory modeling of the natural–technical system “railway track” are considered in order to assess the prospects of using the presented methods. The results of laboratory studies are presented, which have shown their high efficiency in registering a weak useful electrical signal caused by seismoacoustic effects against the background of high-level external industrial and natural interference. In the course of laboratory modeling, it was found that on the amplitude spectra of the output electrical signals of the investigated geological medium in the presence of an elastic harmonic action with a frequency of 70 Hz, the frequency of a harmonic electrical signal with a frequency of 40 Hz is observed. In laboratory modeling, phase images were obtained for the receiving line when simulating the process of sinking the soil base of the railway bed, confirming the presence of a transient process that causes a shift in the initial phase of the signal Δφ = 40° by ~45° (Δφ’ = 85°), which allows detection of the initial stage of failure formation.