Analysis of the Effectiveness of Determining the Horizontal Curvature of a Track Axis Using a Moving Chord

2021 ◽  
Vol 65 (190) ◽  
pp. 85-95
Author(s):  
Władysław Koc
Keyword(s):  
Direct Method ◽  
Railway Track ◽  
Transition Curve ◽  
Analysis Methodology ◽  
Chord Method ◽  
Cartesian Coordinate ◽  
The Individual ◽  
Horizontal Curvature ◽  
Transition Curves ◽  
Type Of Transition

The paper addresses the issue of determining the horizontal curvature of a railway track, noting that it is most often done indirectly – on the basis of measured sags from a chord stretched along the track. Further use of this method would not be justified if there were a direct method for determining the curvature. Therefore, the assumptions of the method for deter-mining the horizontal curvature from “Archives of Civil Engineering”, iss. 4/2020, are presented. This method is based on changes in the slope angles of the moving chord in the Cartesian coordinate system. Two important details are examined: the influence of the length of the chord on the obtained values of curvature and the possibility of determining the location of border points between particular geometrical elements. The analysed variants resulted from the type of transition curves used. It has been found that the length of the chord does not play a significant role in determining the curvature and does not limit the application of this method. At the same time, attention is drawn to the precision of determining the nature of the curvature and its compliance with the theoretical course on transition curves. The analysis shows that, in the moving chord method, it is possible to determine the location of the border points between the individual geometrical elements, but the required chord length must be adapted to the type of transition curve. Keywords: railway, horizontal curvature, moving chord, analysis methodology

On the Planning and Construction of Railway Curved Track

2021 ◽  
Vol 13 (2) ◽  
Author(s):  
Sono Bhardawaj ◽  
Rakesh Chandmal Sharma ◽  
Sunil Kumar Sharma ◽  
Neeraj Sharma
Keyword(s):  
High Speed ◽  
Time Derivative ◽  
Railway Track ◽  
Lateral Acceleration ◽  
Transition Curve ◽  
Railway Vehicle ◽  
Geometric Conditions ◽  
Curve Track ◽  
Curved Track ◽  
Transition Curves

Increasing demand for railway vehicle speed has pushed the railway track designers to develop high-quality track. An important measure of track quality is the character of the transition curve track connecting different intersecting straight tracks. A good transition curve track must be able to negotiate the intermittent stresses and dynamic effects caused by changes in lateral acceleration at high speed. This paper presents the constructional methods for planning transition curves considering the dynamics of movement. These methods consider the non-compensated lateral acceleration, deviation in lateral acceleration and its higher time derivatives. This paper discusses the laying methods of circular, vertical and transition curves. Key aspects in laying a curved track e.g. widening of gauge on curves are discussed in this paper. This paper also suggests a transition curve which is effective not only from a dynamic point of view considering lateral acceleration and its higher time derivative but also consider the geometric conditions along with the required deflection angle.

scholarly journals Smoothed transition curve for railways

2019 ◽  
Vol 2019 (7) ◽  
pp. 19-31 ◽  
Author(s):  
Władysław Koc
Keyword(s):  
Final Section ◽  
Initial Section ◽  
Point Of View ◽  
Smooth Transition ◽  
Railway Track ◽  
Transition Curve ◽  
Practical Implementation ◽  
Circular Arc ◽  
New Form ◽  
Transition Curves

The work draws attention to the existing situation in the area of transition curves used in the geometric layouts of the railway track. Difficulties in the practical implementation and maintenance of very small horizontal ordinates of the transition curve and the ordinates of the gradient due to cant in the initial section, appearing on smooth transition curves, were indicated. The main reason for this situation was the excessive smoothing of the curvature in their initial section. Employing the method of curvature identification by differential equations, a new form of the curve was obtained, which was referred to as the "smoothed transition curve". A definite advantage of this curve was shown, from the implementation point of view, over representing the smooth transition curves of the Bloss curve. . It seems that it could successfully compete with the commonly used clothoid, to which it is similar in the initial section, while it differs significantly along its further length, especially in the final section, where it provides a gentle entry from the transition curve into a circular arc.

scholarly journals Mesomorphism Dependence on Cis-Trans Configuration and Varying Terminal/Lateral Group

2016 ◽  
Vol 65 ◽  
pp. 71-79
Author(s):  
G.N. Bhola ◽  
Umed C. Bhoya
Keyword(s):  
Thermal Stability ◽  
Homologous Series ◽  
Vinyl Ester ◽  
Molecular Structures ◽  
Transition Curve ◽  
Group Efficiency ◽  
Lateral Group ◽  
Normal Manner ◽  
Thermotropic Liquid Crystals ◽  
Transition Curves

A chalconyl trans vinyl ester homologous series of thermotropic liquid crystals RO-C6H4-CH=CH-COO-C6H4-CH=CH-CO-C6H3(OCH3)2meta-para is synthesized and studied with a view to understand and establish the relation between molecular structure and mesomorphism or mesomorphic behaviors. Novel homologous series consists of thirteen homologues (C1to C18). First five (C1to C5) homologues are nonmesogenic. Rest of the homologues (C6to C18) homologues is mesogenic. Monotropically smectogenic character appears from C6to C10homologue and C12to C18homologues are enantiotropically smectogenic. Nematogenic property is totally absent throughout a series. Textures of smectic phase are of the type smectic A or C. Transition curves of a phase diagram behaved in normal manner. Analytical, spectral and thermal data supports the molecular structures of homologues. Odd-even effect is observed for Sm-I/I-Sm transition curve. Thermal stability for smectic is 93.7 °C and the mesomorphic phase lengths from enantiotropic homologues for smectic from minimum to maximum is 6.0 °C to 28.0 °C at the C12and C18homologue respectively. Series is smectogenic without exhibition of nematic property. The group efficiency order on the basis of thermal stability is derived; from comparative study of present series and analogous series.

scholarly journals Exploring Benefits of Using Blending Splines as Transition Curves

2020 ◽  
Vol 10 (12) ◽  
pp. 4226
Author(s):  
Tanita Fossli Brustad ◽  
Rune Dalmo
Keyword(s):  
High Speed ◽  
Transition Curve ◽  
End Points ◽  
Circular Arc ◽  
Track Geometry ◽  
Railway Construction ◽  
Spline Curves ◽  
High Speed Trains ◽  
Transition Curves

Track geometry is a fundamental subject in railway construction. With the demand for increased capacity in terms of load and speed, the need for suitable transitions between consecutive track sections is highly relevant. Properly constructed transition curves lead to improved travel comfort, increased safety, and reduced wear. The well known clothoid curve is widely used as a transition curve; however, the linear curvature is not sufficiently smooth to meet the requirements for railways carrying high speed trains or heavy hauls. Blending spline curves are flexible spline constructions possessing favourable smoothness properties at the end points, which makes them considerable for use as transition curves. This paper demonstrates some selected blending splines applied as transition curves between two existing circular arc segments selected from the Ofotbanen railway. The main results in this paper are related to the smoothness at the end points and the behaviour of the curvature of the curves, where the new transition curves were shown to be smoother than the original clothoid. Another new result is the observation that the proposed method allows for the improvement of existing railways without forcing extensive changes to the original track. Some representative examples are included to highlight the flexibility of this first instance of blending splines as transition curves.

scholarly journals Application of Polynomial Transition Curves for Trajectory Planning on the Headlands

Agriculture ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 144
Author(s):  
Marek Boryga ◽  
Paweł Kołodziej ◽  
Krzysztof Gołacki
Keyword(s):  
Trajectory Planning ◽  
Autonomous Vehicles ◽  
Displacement Function ◽  
Transition Curve ◽  
The Third ◽  
Runge Kutta Method ◽  
Maximal Acceleration ◽  
Matlab Program ◽  
Planning Algorithm ◽  
Transition Curves

This paper presents a method of polynomial transition curve application for making agricultural aggregate movement paths during headland turn drives as well as within the field. Four types of agricultural aggregate paths in five different variant designs are discussed. Each path is composed of only two curves, making the so-called transition bi-curve. The curvature described by the linear function as well as the third, fifth, seventh, and ninth degree polynomials was designated. Moreover, a trajectory planning algorithm in which the movement proceeds along two transition curves composing the so-called bi-curve was proposed. The simulation was carried out applying the MATLAB program in which the 4th order Runge–Kutta method was used. The results were presented by means of figures showing the proposed paths and kinematic quantity courses in the displacement function. The obtained trajectories were compared regarding the size and kinematic quantities. The trajectories, whose curvature is described by the 3° polynomial, were found to possess the smallest absolute values of maximal acceleration and jerk and to lack jerk discontinuity. The proposed solutions can be applied for planning trajectory of not only agriculture machines and aggregates but also autonomous vehicles or mobile robots.

New regulation of the right to a dignified dying in Spain: Repercussions for nursing

2012 ◽  
Vol 19 (5) ◽  
pp. 619-628 ◽  
Author(s):  
Cayetano Fernández-Sola ◽  
José Granero-Molina ◽  
Gabriel Aguilera Manrique ◽  
Adelaida María Castro-Sánchez ◽  
José Manuel Hernández-Padilla ◽  
...  
Keyword(s):  
Decision Making ◽  
Critical Discourse Analysis ◽  
Patient Empowerment ◽  
Cultural Practice ◽  
Critical Discourse ◽  
Analysis Methodology ◽  
The Social ◽  
The Individual ◽  
The Right ◽  
Discourse Practice

Preserving dignity during the dying process requires reviewing the roles of those involved in the treatment, care methods and decision-making. This article examines the participation and responsibility assigned to nurses regarding decision-making in the final stages of life, as laid out in the Rights to and Guarantee of Dignity for the Individual During the Process of Death Act. This text has been analysed on the levels of socio-cultural practice and discourse practice, using the critical discourse analysis methodology. The results show that, although the law is another result of the social trend of patient empowerment, the responsibility of the nurses is not recognised, and they are left out of the decision-making process in the final stages of life.

Synthesis of Stationary Cams

1999 ◽  
Vol 121 (1) ◽  
pp. 169-172 ◽  
Author(s):  
L.-I. Wu ◽  
P.-H. Fang
Keyword(s):  
Design Process ◽  
Transition Curve ◽  
Gradual Change ◽  
Tool Magazine ◽  
Cam Design ◽  
Circular Arcs ◽  
Automatic Tool ◽  
Pitch Curve ◽  
Straight Lines ◽  
Transition Curves

This paper presents a method for designing stationary cams with constant speed roller followers. A stationary cam is immovable, but it guides its follower to produce a desired motion with the follower being driven by other links. In order to avoid infinite jerk of the follower motion, the pitch curve of a stationary cam should consist of pieces of transition curve, which provide gradual change in curvature and are interposed between straight lines and circular arcs. The general parametric equations of transition curves are derived and the cam design process is demonstrated. This method is applicable for designing the guideways of tool magazine in automatic tool-changing system of the machine center.

The use of chromium sesquioxide to measure the digestibility of carotene by goats and cows

1951 ◽  
Vol 41 (1-2) ◽  
pp. 179-186 ◽  
Author(s):  
R. Chanda ◽  
Helen M. Clapham ◽  
Mary L. McNaught ◽  
E. C. Owen
Keyword(s):  
Direct Method ◽  
Apparent Digestibility ◽  
Lactating Goats ◽  
The Individual

The digestibility of carotene in dried grass was measured by the Cr2O3 method in both cows and goats. In the goats the direct method was simultaneously used for comparison with the Cr2O3 method.The main conclusions were:1. When mixed with the concentrate portion of the ration of lactating goats, Cr2O3 was recovered in the faeces in four experiments in amounts equal to 100·0, 99·1, 99·1 and 96·0% of the amount ingested.2. The apparent digestibility of carotene in the goat was measured both directly by the use of metabolism crates and indirectly by using Cr2O3 as an indicator of equivalence of faeces and food. By the former method digestibilities of carotene in four goats were 68·7, 62·7, 61·8 and 59·6%. The corresponding digestibilities obtained from the same faeces samples by the Cr2O3 method were 67·4, 62·9, 61·8 and 58·9%.3. In six cows, on the diet similar to that of the goats, the Cr2O3 method showed that 59·3, 54·0, 54·4, 54·4, 57·1 and 55·5% of carotene was apparently digested.4. Reasons for preferring the use of added Cr2O3 to natural constituents of the food as a marker are discussed.5. The individual results from cows and goats have been statistically analysed to partition the various sources of variance, and it has been shown that fewer animals for a longer time give a more reliable result than more animals for a shorter time.

Bloodtyping and Twin Zygosity. Reassessment and Extension

1980 ◽  
Vol 29 (2) ◽  
pp. 103-120 ◽  
Author(s):  
Ronald S. Wilson
Keyword(s):  
Direct Method ◽  
Individual Case ◽  
Differential Probability ◽  
Dizygotic Twins ◽  
Similarities And Differences ◽  
Diagnostic Question ◽  
The Individual

The determination of twin zygosity by bloodtyping is reconsidered, and the model for the individual case is reformulated. The crucial diagnostic question may be phrased as follows: Given the particular array of bloodgroup phenotypes that the twins display and are concordant for, how might this array have been obtained by a pair of dizygotic twins, and how might the array have been obtained by a monozygotic pair? The solution yields a differential probability value that is uniquely tailored to the actual phenotype array shown. The procedure offers a coherent and more direct method for arriving at the needed probability figures, and it is recommended to supersede previous methods. Some similarities and differences between the methods are discussed.

scholarly journals Analytical design method of reverse curves

2016 ◽  
Vol 2016 (6) ◽  
pp. 14-25
Author(s):  
Władysław Koc
Keyword(s):  
Design Method ◽  
Railway Track ◽  
Mathematical Notation ◽  
Satellite Measurements ◽  
New Approach ◽  
Analytical Design ◽  
Circular Arcs ◽  
Mobile Satellite ◽  
Transition Curves

The paper deals with a new approach relating to the design of the region of railway track direction alteration adapted to Mobile Satellite Measurements technique. The method may be particularly useful in situations when both the straights of the route directions cannot be connected in an elementary way using a circular arc with transition curves; this also refers to the application of a compound curve. Thus the only solution becomes the application of two circular arcs of opposite curvature signs to the geometric system, i.e. the use of an inverse curve. The solution of the design problem takes advantage of a mathematical notation and concentrates on the determination of universal equations describing the entire geometric system. This is a sequential operation involving successive parts of the system. The presented method has been illustrated by appropriate calculation examples.

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