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Journal articles on the topic 'Vertical curve'

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Published: 4 June 2021
Last updated: 9 February 2022

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1

Sun, Jian Cheng, and Chen Feng Chen. "Length Requirements for New Single-Arc Unsymmetrical Crest Vertical Curve for Highways." Advanced Materials Research 1065-1069 (December 2014): 755–59. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.755.

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Existing highway vertical curves may be grouped into two categories: symmetrical vertical curves and unsymmetrical vertical curves. In the past vertical curves design, parabolic arc was used as the vertical curve. This paper presents the new single-arc unsymmetrical vertical curve which is include only one cubic parabola. This curve has the gradual change of the rates of change in grade so that it can provide more comfort to the driver. This paper mainly presents the method by which to find the minimum length for a new single-arc unsymmetrical crest vertical curve based on the minimum sight distance . The discussion will be divided into two situations: the sight distance is longer than the curve length and the sight distance is not longer than the curve length.
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2

Hasan, Moudud, Tarek Sayed, and Yasser Hassan. "Influence of vertical alignment on horizontal curve perception: effect of spirals and position of vertical curve." Canadian Journal of Civil Engineering 32, no. 1 (February 1, 2005): 204–12. http://dx.doi.org/10.1139/l04-090.

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Several studies have shown that the perception of horizontal curves can be influenced by an overlapping vertical alignment. A previous two-phase study investigated the hypothesis that a horizontal curve appears flatter when overlapping with a vertical sag curve and sharper when overlapping with a vertical crest curve. The study concluded that the hypothesis was valid. The study also developed several statistical models to estimate the perceived radius of horizontal curves in a combined alignment. This study extends the earlier work by investigating the effect of additional geometric parameters on the perception. The parameters examined include the presence of spiral curves, the length of the spirals, and the position of the vertical curve midpoint relative to the horizontal curve. It was found that (1) driver misperception of the horizontal curvature increases as the radius of the horizontal curve increases, (2) the presence of a spiral curve affects driver perception of the horizontal curvature in the case of crest combination only, (3) the length of the spiral curve has no effect on the perception whether on crest or sag combinations, and (4) while the effect of the position of the vertical curve midpoint relative to the horizontal curve is not statistically significant, it seems that the perception problem appears to diminish as the positive offsets increases.Key words: highway geometric design, visual perception, combined alignment.
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3

Rehman, Saad Abdul, Sadia Rizwan, Syed Shah Faisal, and Syed Sheeraz Hussain. "Association of Curve of Spee with Vertical Skeletal Patterns." Journal of the Pakistan Dental Association 29, no. 04 (November 15, 2020): 254–58. http://dx.doi.org/10.25301/jpda.294.254.

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OBJECTIVE: To find the mean curve spee depth and association in three different skeletal vertical patterns (Hypodivergent, Normodivergent and Hyperdivergent). METHODOLOGY: Orthodontic models of mandibular arch and Lateral cephalogram of 110 patients with the mean age of 17.16±4 years, 26.4% (N=29) males and 73.6% (N=81) females were taken from the patients who visited for the orthodontic treatment, to the Department of Orthodontics of Karachi Medical and Dental College. Skeletal divergence defined by the mandibular plane (Lower border of mandible) to sella-nasion line angle (SN-MP). It was measured on lateral cephalogram and Curve of spee depth measured on mandibular cast. RESULTS:Out of 110 patients 20.9% (N= 23) were hypodivergent, 29.1% (N=32) were normodivergent and 50% (N=55) were hyperdivergent. The curve of spee among these three groups were 3.39±0.30mm, 2.62±0.23mm and 2.02±0.45mm. One-way ANOVA has been applied and it showed highly significant differences in the value of curve of spee depth among three vertical skeletal patterns with the p-value of 0.000. Moving from Hypodivergent to Hyperdivergent cases, the curve of Spee depth reduces. CONCLUSION: It has been found that there is a significant difference in curve of spee among hypodivergent, normodivergent and hyperdivergent patients. KEYWORDS: Dentistry, Curve of Spee, Vertical Skeletal Patterns, Orthodontic Diagnosis. HOW TO CITE: Rehman SA, Rizwan S, Faisal SS, Hussain SS. Association of curve of spee with vertical skeletal patterns. J Pak Dent Assoc 2020;29(4):254-258.
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4

Easa, Said M. "Length Requirements for New Single-Arc Unsymmetrical Vertical Curve." Transportation Research Record: Journal of the Transportation Research Board 2060, no. 1 (January 2008): 38–45. http://dx.doi.org/10.3141/2060-05.

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Traditional unsymmetrical vertical curves consist of two parabolic arcs smoothly connected at the point of common curvature. A new single-arc unsymmetrical vertical curve that takes the form of a cubic instead of parabolic function has been recently developed. The curve has a rate of change in grade that gradually varies between the start and end of the vertical curve. The single-arc curve eliminates the sudden change that exists in curvature of traditional two-arc unsymmetrical vertical curves. This paper first develops the sight distance (SD) relationships for the new single-arc curve (crest type). With these relationships, the SD profile for the new curve is established and its shape shows a substantial improvement over the abrupt-type SD profiles of the two-arc curves. The length requirements that satisfy stopping, passing, and decision SD guidelines of AASHTO are then presented. Some examples are used to illustrate the use of the developed design aids. The new single-arc curve builds on previously developed unsymmetrical vertical curves to improve curve characteristics that hopefully will promote road safety.
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5

Hassabo, Adil I. "Vertical Curve Computations Using a Developed Calculator." FES Journal of Engineering Sciences 8, no. 2 (November 10, 2020): 118–21. http://dx.doi.org/10.52981/fjes.v8i2.58.

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In this paper, an electronic calculator for vertical curve computations is developed in Microsoft Windows. The developed calculator used is successfully for vertical curve computations and requires entering the curve length, tangent grades, setting out interval, and the elevation of the intersection points. Computations of vertical curves by the developed calculator are faster, easier, accurate, and less subject to errors comparable to the traditional method of calculations. Finally, the results obtained by the traditional and developed methods are presented for checking the behavior of the developed calculator.
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6

Easa, Said M. "New and improved single-arc unsymmetrical vertical curve for highways." Canadian Journal of Civil Engineering 34, no. 10 (October 1, 2007): 1216–21. http://dx.doi.org/10.1139/l07-060.

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Existing unsymmetrical vertical curves consist of two parabolic arcs smoothly connected at the point of common curvature. As such, each arc has a constant rate of change in grade. This paper presents a new and improved single-arc unsymmetrical vertical curve for highways that takes the form of a cubic function. The curve has a rate of change in grade that varies gradually between the beginning and end of the curve. The new curve lies below the sharper arc and above the flatter arc of the existing equal-arc unsymmetrical (EAU) vertical curve, thus smoothing out the EAU curve. In addition, the new curve slightly improves highway sight distance in most of the cases studied. The single-arc curve exhibits several interesting properties. The forward and backward offsets are not equal, nor are the basic and reverse offsets. The offsets of the new and EAU curves are equal at the mid-point of the curve. Also, the rate of change in grade of the new curve at the mid-point equals the average of the rates of change in grade of the two arcs of the EAU curve. The new curve exhibits several important properties and, as such should be of interest to highway designers.Key words: unsymmetrical vertical curves, single arc, highways, offset, sight distance, driver comfort.
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7

Kwon. "Determination of Dimension of Vertical Curve Elements at Parking Lot Ramps." Journal of the Korean Society of Civil Engineers 35, no. 3 (2015): 607. http://dx.doi.org/10.12652/ksce.2015.35.3.0607.

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8

Fitzpatrick, Kay, C. Brian Shamburger, Raymond A. Krammes, and Daniel B. Fambro. "Operating Speed on Suburban Arterial Curves." Transportation Research Record: Journal of the Transportation Research Board 1579, no. 1 (January 1997): 89–96. http://dx.doi.org/10.3141/1579-11.

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Free-flow speeds were collected at both a control section and a curve section at 14 surburban sites with horizontal curves and 10 suburban sites with vertical curves. The scatter plots of the 85th percentile speed versus approach density indicate that when the approach density is between 3 and 15 approaches per km, approach density does not influence speed. Regression analysis indicated that the curve radius for horizontal curves and the inferred design speed for vertical curves can be used to predict the 85th percentile speed on curves for vehicles on the outside lane of a four-lane divided suburban arterial. For horizontal-curve sites, a curvilinear relationship exists between curve radius and the 85th percentile speed. A linear relationship provided the best fit between the inferred design speed and the 85th percentile speed for the vertical curve sites. For the horizontal and vertical curve sites, the speed at which 85th percentile speed becomes less than the inferred design speed is lower for suburban arterials than for rural highways. Drivers on suburban horizontal curves operate at speeds greater than the inferred design speed for curves designed for speeds of 70 kph or less, whereas on rural, two-lane roadways, drivers operate at speeds greater than the inferred design speed for curves designed for speeds of 90 kph or less. For vertical curves, the speeds at which drivers operate greater than the inferred design speed are 90 kph for suburban arterials and 105 kph for rural highways. These results are within 12 kph of the observed 85th percentile speeds on nearby control sections (approximately 80 kph for suburban arterials and 100 kph on rural highways).
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9

Muthusubramanyam, M. "Graphical Solution for Vertical Curve Computation." Journal of Surveying Engineering 129, no. 3 (August 2003): 125–26. http://dx.doi.org/10.1061/(asce)0733-9453(2003)129:3(125).

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10

Easa, Said M., and Fujian Wang. "Estimating continuous highway vertical alignment using the least-squares method." Canadian Journal of Civil Engineering 37, no. 10 (October 2010): 1362–70. http://dx.doi.org/10.1139/l10-088.

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Highway profile information may not be available or may not be up to date, especially for old highways. In these cases, profile data are collected using global positioning systems (GPS) or by extracting them from digital images. This paper presents an optimization model for estimating the parameters of continuous vertical alignments, involving multiple parabolic vertical curves that best fit existing highway profile data using the least-squares method. The optimization involves two levels: single-curve optimization and multiple-curve optimization. The former is used to obtain the approximate length of each vertical curve based on the approximate tangent parameters determined from the outline controlling points. The latter is used to obtain the global optimal parameters for tangents and vertical curves. The model is validated and applied using actual data of a vertical alignment. The proposed model presents a useful extension to existing methods for estimating simple vertical alignments and therefore should be of interest to highway engineering professionals.
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11

Omokawa, Masahiro, Mitsuru Saito, Katsuya Tanifuji, Hitoshi Soma, and Takumi Ishii. "355820 HIGH-SPEED RUNNING OF TILTING VEHICLE USING AIR SPRINGS ON CURVED SECTION OVERLAPPED WITH VERTICAL CURVE(Bogie,Technical Session)." Proceedings of International Symposium on Seed-up and Service Technology for Railway and Maglev Systems : STECH 2009 (2009): _355820–1_—_355820–6_. http://dx.doi.org/10.1299/jsmestech.2009._355820-1_.

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12

Mohazzabi, Pirooz. "Isochronous anharmonic oscillations." Canadian Journal of Physics 76, no. 8 (August 1, 1998): 645–57. http://dx.doi.org/10.1139/p98-029.

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The problem of a particle oscillating without friction on a curve in a vertical plane (referred to as a vertical curve) is addressed. It is shown that there are infinitely many asymmetric concave vertical curves on which oscillations of a particle remain isochronous. The general equation of these curves is derived, and a one-to-one correspondence between these curves and one-dimensional potentials is established. The results are compared with the existing literature, and an interesting nontrivial special case is discussed. Some issues regarding interpretation of the results in the context of action and angle variables are also addressed. PACS No. 03.20
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13

Hassan, Yasser, Said M. Easa, and A. O. Abd El Halim. "Analytical Model for Sight Distance Analysis on Three-Dimensional Highway Alignments." Transportation Research Record: Journal of the Transportation Research Board 1523, no. 1 (January 1996): 1–10. http://dx.doi.org/10.1177/0361198196152300101.

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Existing sight distance models are applicable only to two-dimensional (2-D) separate horizontal and vertical alignments or simple elements of these separate alignments (vertical curve, horizontal curve). A new model is presented for determining the available sight distance on 3-D combined horizontal and vertical alignments. The model is based on the curved parametric elements that have been used in the finite element method. The elements presented are rectangular (4-node, 6-node, and 8-node elements) and triangular. These elements are used to represent various features of the highway surface and sight obstructions, including tangents (grades), horizontal curves, vertical curves, traveled lanes, shoulders, side slopes, cross slopes, superelevation, lateral obstructions, and overpasses. The available sight distance is found analytically by examining the intersection between the sight line and the elements representing the highway surface and the sight obstructions. Application of the new model is illustrated using numerical examples, and the results show that existing 2-D models may underestimate or overestimate the available sight distance. The proposed model should be valuable in establishing design standards and guidelines for 3-D highway alignments and determining the effect of various highway features on sight distance.
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14

Liu, Peng-Fei, Wan-Ming Zhai, Kai-Yun Wang, Quan-Bao Feng, and Zai-Gang Chen. "Theoretical and experimental study on vertical dynamic characteristics of six-axle heavy-haul locomotive on curve." Transport 33, no. 1 (May 4, 2016): 291–301. http://dx.doi.org/10.3846/16484142.2016.1180638.

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This paper presents a method to study the vertical dynamic characteristics of a heavy-haul locomotive in curve. A quasi-static analysis model based on the static force equilibrium relationship is established to investigate the load bearing characteristics of suspension system when the locomotive runs through the curve. Then a locomotive–track coupled dynamics model is used to analyse the dynamic characteristics of wheel load in curves. Finally, a field test in curve is carried out to validate the simulated results. The theoretical analysis results indicate that due to the different twist shapes of track on the entry and exit transition curves, for some specific position in the suspension system or wheel arrangements, the corresponding vertical load along the curve length presents an asymmetry about the section of circular curve. The asymmetry is predominantly caused by the Superelevation Angle Differences (SADs) between car body, bogie frames and wheelsets. A distinct phenomenon is that the outer wheel–rail vertical load of the first axle increases when the locomotive enters the transition curve and then reduces when it exits. These results are expected to provide theoretical guidance to the design of the heavy-haul railways. It is suggested that the asymmetric characteristics of the wheel loads can be improved by some measures, such as adopting a low vertical stiffness in the secondary suspension and increasing the transition curve length.
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15

Selyukov, D. D., and N. V. Vishnyakov. "INFLUENCE OF VERTICAL CURVE ON HIGHWAY TRAFFIC SAFETY." Science & Technique 17, no. 3 (May 31, 2018): 255–60. http://dx.doi.org/10.21122/2227-1031-2018-17-3-255-260.

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The paper is devoted to a challenging problem of ensuring traffic safety on the sections of a highway vertical curve and it provides an analysis for works concerning design, lay-out and organization of a project roadway. A change in vehicle speed has been analyzed depending on the length of a curve and a maximum longitudinal slope of a project roadway. The paper presents statistical data about accidents in the Republic of Belarus for several years on the sections of curves pertaining to project roadways. Comparative analysis of difference between point marks on a parabola is given in the paper and the parabola is inscribed in the fracture of the project roadway while using two methods. The paper presents the following errors: geodetic measurements in excesses while laying out pavement, elevation points along pavement axis while making road pavement. Emergence of centrifugal force causes a change in shearing and holding forces. Excess of the shearing force on the holding one leads to spontaneous sliding in the direction of a shearing force vector. Technical solutions have been developped on the basis of systematic functional and active deterministic method. The solutions are protected by invention patents of the Republic of Belarus and they ensure safety passages of highway sections with this type of curves in a longitudinal profile. While constructing and accepting a road for operation it is necessary to control references of curve elements in the longitudinal profile according to the results of executive surveys and in case of operation it is necessary to inform a driver about a safety speed for a passage through such sections
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16

Easa, Said M., and Yasser Hassan. "Development of transitioned vertical curve I Properties." Transportation Research Part A: Policy and Practice 34, no. 6 (August 2000): 481–96. http://dx.doi.org/10.1016/s0965-8564(99)00036-1.

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17

Hu, W. C., Francis Tan, and Alan Barnes. "New Solutions to Optimum Vertical Curve Problem." Journal of Surveying Engineering 130, no. 3 (August 2004): 119–25. http://dx.doi.org/10.1061/(asce)0733-9453(2004)130:3(119).

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18

Hassan, Yasser. "Improved Design of Vertical Curves with Sight Distance Profiles." Transportation Research Record: Journal of the Transportation Research Board 1851, no. 1 (January 2003): 13–24. http://dx.doi.org/10.3141/1851-02.

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Design of vertical alignment is one of the main tasks in highway geometric design. This task requires, among other things, that the designer ensure drivers always have a clear view of the road so they can stop before hitting an unexpected object in the road. Therefore, the ability to determine the required and available stopping sight distance (SSD) at any point of the vertical alignment is essential for the design process. Current design guides in the United States and Canada provide simple analytical models for determining the minimum length of a vertical curve that would satisfy the sight distance requirement. However, these models ignore the effect of grade on the required SSD. Alternative approaches and models have also been suggested but cover only special cases of vertical curves. Two specific models were expanded to determine the required SSD on crest and sag vertical curves. By comparing profiles of available SSD and required SSD on examples of vertical curves, it was shown that current North American design practices might yield segments of the vertical curve where the driver’s view is constrained to a distance shorter than the required SSD. An alternative design procedure based on the models was developed and used to determine the minimum lengths of crest and sag vertical curves. Depending on the approach grade, these new values of minimum curve length might be greater than or less than values obtained through conventional design procedures. Design aids were therefore provided in tabular form for designers’ easy and quick use.
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19

Martins, Renato Parsekian. "Early vertical correction of the deep curve of Spee." Dental Press Journal of Orthodontics 22, no. 2 (April 2017): 118–25. http://dx.doi.org/10.1590/2177-6709.22.2.118-125.sar.

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ABSTRACT Even though few technological advancements have occurred in Orthodontics recently, the search for more efficient treatments continues. This paper analyses how to accelerate and improve one of the most arduous phases of orthodontic treatment, i.e., correction of the curve of Spee. The leveling of a deep curve of Spee can happen simultaneously with the alignment phase through a method called Early Vertical Correction (EVC). This technique uses two cantilevers affixed to the initial flexible archwire. This paper describes the force system produced by EVC and how to control its side effects. The EVC can reduce treatment time in malocclusions with deep curves of Spee, by combining two phases of the therapy, which clinicians ordinarily pursue sequentially.
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20

Huang, Zhi Lu, and Kuan Min Chen. "Research on the Quantitative Technical Index of Combining Horizontal and Vertical Curves of Expressway." Applied Mechanics and Materials 668-669 (October 2014): 1442–48. http://dx.doi.org/10.4028/www.scientific.net/amm.668-669.1442.

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The factors of combining horizontal and vertical curves are analyzed for guiding road design on expressway in practice and ensuring the safety and comfort of vehicle. The influences on drivers' by all kinds of flat vertical combination characteristics are researched. The necessary conditions meeting the horizontal and vertical combination rationality are proposed through the highway and driver characteristics. The identification sight on convex and concave vertical curve under driving at night and overpass are studied based on driver's sight guidance; the indexes of the vertical curve radius and length that my not meet horizontal including vertical combination are raised. Based on road surface drainage, the indexes that may not meet horizontal including vertical combination is proposed from the aspects of longitudinal slope, cross slope drainage and pavement structure. Comprehensive the design of flat vertical combination put forward the quantitative technical indicators that may not meet horizontal including vertical combination.
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21

Easa, Said, and Essam Dabbour. "Establishing design guidelines for compound horizontal curves on three-dimensional alignments." Canadian Journal of Civil Engineering 32, no. 4 (August 1, 2005): 615–26. http://dx.doi.org/10.1139/l05-016.

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In current design guides, the minimum radii of compound horizontal curves are based on the design requirements of simple horizontal curves for each arc on flat terrain. Such a design ignores the effects of compound curvature and vertical alignment. This paper uses computer simulation software to establish the minimum radius requirements for compound curves, considering these effects. The actual lateral acceleration experienced by a vehicle negotiating a two-dimensional (2-D) simple curve is recorded as a base scenario to facilitate the analysis of a compound curve on a flat terrain or combined with vertical alignment (three-dimensional (3-D) compound curves). The vertical alignments examined include upgrades, downgrades, crest curves, and sag curves. Mathematical models for minimum radius requirements were developed for flat and 3-D compound curves. Three types of design vehicles were used. The results show that an increase in the minimum radius ranging from 5% to 26% is required to compensate for the effects of both compound curvature and vertical alignment.Key words: highway geometric design, compound horizontal alignments, side friction, vehicle simulation, 3-D alignments.
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22

Sun, Bing, Wenyang Shi, Rui Zhang, Shiqing Cheng, Chengwei Zhang, Shiying Di, and Nan Cui. "Transient Behavior of Vertical Commingled Well in Vertical Non-Uniform Boundary Radii Reservoir." Energies 13, no. 9 (May 6, 2020): 2305. http://dx.doi.org/10.3390/en13092305.

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Transient behavior analysis, including rate transient analysis (RTA) and pressure transient analysis (PTA), is a powerful tool to investigate the production performance of the vertical commingled well from long-term production data and capture the formation parameters of the multilayer reservoir from transient well testing data. Current transient behavior analysis models hardly consider the effect of vertical non-uniform boundary radii (VNBR) on transient performances (rate decline and pressure response). The VNBR may cause an obvious novel radial flow regime and rate decline type, which can easily be mistaken as a radial composite reservoir. In this paper, we present a VNBR transient behavior analysis model, the extended vertical uniform boundary radii (VUBR), to investigate the rate decline behavior and pressure response characteristics through diagnostic type curves. Results indicate that the dimensionless production integral derivative curve or pressure derivative curve can magnify the differences so that we can diagnose the outer-convex shape and size of the VNBR. Therefore, it is significant to incorporate the effects of VNBR into the transient behavior analysis models of the vertical commingled well, and the model proposed in this paper enables us to better evaluate well performance, capture formation characteristics and diagnose flow regimes based on rate/pressure transient data.
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23

Dong, Yaping, and Jinliang Xu. "Estimation of Vehicle Carbon Emissions in China Accounting for Vertical Curve Effects." Mathematical Problems in Engineering 2020 (August 29, 2020): 1–20. http://dx.doi.org/10.1155/2020/1595974.

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Predicting vehicle carbon emissions on vertical curve sections can provide guidance for low-carbon vertical profile designs. Given that the influence of vertical curve design indicators on the fuel consumption and CO2 emissions of vehicles are underexplored, this study filled this research gap by establishing a theoretical carbon emission model of vehicles on vertical curve sections. The carbon emission model was established based on Xu’s vehicle energy conversion model, the conversion model of energy, fuel consumption, and CO2 emissions. The accuracy of the theoretical carbon emission model and the CO2 emission rules on vertical curve sections were verified by field test results. Field tests were carried out on flat sections, longitudinal slope sections, and various types of vertical curve sections, with five common types of vehicles maintaining cruising speed. The carbon emission rate effects on the vertical curve are closely related to the gradient and irrelevant of the radius. On the vertical profile composed with downhill/asymmetric/symmetrical vertical curve with a gradient greater than the balance gradient, the carbon emission rate is determined by the gradient and radius. The influence of the gradient on carbon emissions of vehicle on these vertical profiles was more significant than the radius. The radius is irrelevant to the carbon emission rate on the other forms of vertical profile. These results may benefit highway designers and engineers by providing guidelines regarding the environmental effects of highway vertical curve indexes.
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Fan, Xianghui, Bin Li, Yongfu Zhang, Guoqiang Du, and Hua Liu. "Dynamic influence of the plane curve radius on vertical- circular overlapping lines of high-speed railway." E3S Web of Conferences 248 (2021): 03033. http://dx.doi.org/10.1051/e3sconf/202124803033.

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In order to reasonably match the horizontal and vertical sections of high-speed railway lines, the vehicle-line spatial coupling model of the vertical-circular overlapping line is established, based on the multi-body dynamics simulation software SIMPACK,. The dynamic indexes of train passing through vertical-circular overlapping lines are calculated when the radii of different plane curves match the corresponding superelevation value. The results show that: on the vertical-circular overlapping line, it is suggested that the maximum plane curve radius is 9000m.The existence of the convex vertical-circular overlapping line worsens the safety of train operation and passenger comfort. The existence of the concave vertical-circular overlapping line is the opposite, but it increases rail wear and the workload of maintenance. The vertical-circular overlapping line has the most obvious influence on the vertical acceleration and the vertical Sperling index of the body. The vertical acceleration of the body is superimposed at the plane gentle circle point and the starting point of the vertical curve, which has a great impact on the stability of the train operation.
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25

You, Run Wei. "A Study on the Requirements for Minimum Longitudinal Slope of the Vertical Curve on the Freeway." Applied Mechanics and Materials 178-181 (May 2012): 1474–78. http://dx.doi.org/10.4028/www.scientific.net/amm.178-181.1474.

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The varying laws of the longitudinal grade at the partial any point on the vertical curve in the course of the freeway’s profile design were discussed via the analytical formulas calculation, and the minimum longitudinal gradient and the length of roads which cannot meet the current requirements were found out, then application effect of vertical curves with the large radius was explored. On this condition, some countermeasures and suggestions were provided for the reasonable design of the vertical curves.
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Hassan, Yasser, Said M. Easa, and A. O. Abd El Halim. "Modeling Headlight Sight Distance on Three-Dimensional Highway Alignments." Transportation Research Record: Journal of the Transportation Research Board 1579, no. 1 (January 1997): 79–88. http://dx.doi.org/10.3141/1579-10.

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Sight distance is one of the major elements that must be considered in the geometric design to achieve safe and comfortable highways. Daytime sight distance has been extensively studied, and analytical models for two-dimensional (2-D) and three-dimensional (3-D) alignments have been developed. However, nighttime (headlight) sight distance has received less attention. Despite the higher accident rate during nighttime than during daytime, existing analytical models evaluating headlight sight distance are very primitive. Moreover, the interaction between the horizontal and vertical alignments has not been modeled. A four-phase analytical model for headlight sight distance on 3-D combined alignments is presented. The model is an application of the finite-element technique in highway geometric design. The model can determine the maximum distance that can be covered by the vehicle’s headlights and that is not obstructed by any sight obstructions including the road surface. On the basis of this analytical model, computer software was developed and used in a preliminary application for 3-D headlight sight distances on a sag or crest vertical curve combined with a horizontal curve. The application showed that the 3-D sight distance on sag vertical curves was generally lower than the corresponding 2-D value when the sag curve was overlapping with a horizontal curve. On the other hand, the overlapping of horizontal curves with crest vertical curves enhanced the 3-D sight distance. The difference between 2-D and 3-D sight distance values in both cases increased with a decrease in the horizontal curve radius and an increase in the pavement cross slope. The model was proved to be extremely valuable in establishing 3-D highway geometric design standards.
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Easa, Said M., and Yasser Hassan. "Development of transitioned vertical curve II Sight distance." Transportation Research Part A: Policy and Practice 34, no. 7 (September 2000): 565–84. http://dx.doi.org/10.1016/s0965-8564(99)00037-3.

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28

Easa, Said M. "Three-Arc Vertical Curve for Constrained Highway Alignments." Journal of Transportation Engineering 124, no. 2 (March 1998): 163–71. http://dx.doi.org/10.1061/(asce)0733-947x(1998)124:2(163).

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29

Liu, Xing Wang. "Road Curve Speed Control Engineering Study." Applied Mechanics and Materials 66-68 (July 2011): 793–97. http://dx.doi.org/10.4028/www.scientific.net/amm.66-68.793.

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Horizontal curves have been recognised as a significant safety issue for many years, a more important factor than road width, vertical clearance or sight distance. This study investigates the issue of speed selection through curves from several different perspectives. The relationship between safety and curve speed in SiChuan provinces was analysed using data from the local crash database. A sample of curves was selected and surveyed. Following this, acurve treatments for controlling Curve speed for different vehicles was developed based on many factors that has influence on safey.
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Easa, Said M., Yasser Hassan, and A. O. Abd El Halim. "Sight distance evaluation on complex highway vertical alignments." Canadian Journal of Civil Engineering 23, no. 3 (June 1, 1996): 577–86. http://dx.doi.org/10.1139/l96-866.

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Sight distance (stopping, passing, and decision) is a key element in highway geometric design. Existing models for evaluating sight distance on vertical alignments are applicable only to simple, isolated elements such as a crest vertical curve, a sag vertical curve, and a reverse vertical curve (a sag curve following a crest curve, or vice versa). This paper presents an analytical methodology for evaluating sight distance on complex vertical alignments that involve any combination of vertical alignment elements. The methodology can be used for evaluating passing sight distance on two-lane highways, and stopping sight distance and decision sight distance on all highways. Sight distance controlled by the headlight beam can also be evaluated. The locations of sight-hidden dips, which may develop when a sag vertical curve follows a crest vertical curve with or without a common tangent, can be determined. Also, sight distances obstructed by overpasses are evaluated. A profile of the available sight distance can be established and used to evaluate sight distance deficiency and the effect of alignment improvements. A software was developed and can be used for determining the available sight distance accurately. The software may replace the current field and graphical practice for establishing the no-passing zones and evaluating stopping and decision sight distances on complex vertical alignments. Key words: sight distance, vertical alignment, highway, passing zones.
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Tsai, Yichang (James), Yi-Ching Wu, Cibi Pranav P. S., and Chengbo Ai. "Identification of Site Characteristics for Proactive High-Friction Surface Treatment Site Selection using Sensor-Based, Detailed, Location-Referenced Curve Characteristics Data." Transportation Research Record: Journal of the Transportation Research Board 2672, no. 38 (June 21, 2018): 69–80. http://dx.doi.org/10.1177/0361198118780709.

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The Georgia Department of Transportation (GDOT) has developed a proactive high-friction surface treatment (HFST) program for curve sites prone to run-off-road (ROR) crashes. Using crash data and a single-criterion, ball bank indicator (BBI) value, GDOT seeks to maximize the return on its HFST investment. GDOT has partnered with Georgia Tech to identify additional factors for its HFST site-selection (HFST-SS) decision-making process by leveraging high-resolution, full-coverage sensor data (e.g., GPS and LiDAR). This paper proposes a methodology to identify site characteristics that can be used in GDOT’s HFST-SS process by leveraging the sensor data and automatically extracting roadway curve features as follows: (a) roadway data collection using state-of-the-art sensing technologies, (b) automatic extraction of detailed site characteristics data and curve information, (c) curved-based roadway segmentation using the extracted curve information; (d) spatial integration of curve-site characteristics data (CSCD); (e) analysis of CSCD and ROR crashes to identify additional factors for HFST site selection. A case study using CSCD extracted from Georgia State Route 2 demonstrates the proposed methodology. Results show that on sharp curves having comparable site characteristics, vertical grades greater than 3% play an important role in ROR crashes. Therefore, a vertical grade greater than 3% could be considered as an additional HFST-SS factor along with the current BBI criterion.
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32

Liu, Jiang. "Highway Alignment Parameters Design and Capacity Analysis on Two-Lane Highway." Applied Mechanics and Materials 539 (July 2014): 860–66. http://dx.doi.org/10.4028/www.scientific.net/amm.539.860.

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A two-lane highway is an undivided highway with only one lane of traffic in each direction. Two-lane highways are one of the most common roadways at mountainous areas in China. Due to the wider range to choose the horizontal and vertical curves in the design of two-lane highways, the combination of both leads to larger differences on two-lane highway capacities. Thus, the highway alignments are one of the key factors which affect the two-lane highway capacities. According to the empirical data and existing studies, it is regarded that there is no impacts on the capacity for horizontal curves with a radius more than 400m and vertical curves with the gradient less than 3%. Two concepts are defined as effective bending and effective gradient which represent the extent the horizontal curve bends and the steepness of vertical curve respectively. The method to calculate effective bending of horizontal curve and steepness of vertical curve is given and its relevant properties are also discussed. According to the simulation results and the principle of speed differences, the effective bending and effective gradient have been classified into 7 and 6 levels, separately. As a result, there will be 42 combinations of different highway alignments of two-lane highways based on the different combinations of the effective bending and effective gradient. Under this circumstance, the relationship of speed-volume and volume-PTSF (percent time spend following) are obtained from the simulation results. Finally, the capacity of two-lane highway is given under different highway alignments of two-lane highway at mountainous areas in China.
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33

Kobryń, Andrzej. "Transition curves in vertical alignment as a method for reducing fuel consumption." BALTIC JOURNAL OF ROAD AND BRIDGE ENGINEERING 9, no. 4 (February 20, 2014): 260–68. http://dx.doi.org/10.3846/bjrbe.2014.32.

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This paper presents a new approach to the fuel consumption reduction. This approach is based on vertical curve designs based on transition curves. The work presents selected curves, which are used for this purpose. Moreover, the results of comparative studies are shown for these curves, carried out in order to compare the possible reduction of fuel consumption in vertical curves designed using both conventional and proposed methods. Numerical studies were based on German engineering guidelines. In the case of vertical arcs formed by transition curves, fuel consumption indexes prove to be significantly lower than in curves based on a grade line consisting of straight lines with parabolic arcs. The obtained results indicate the advisability of forming vertical curves using transition curves.
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34

Sengpiel, Klaus‐Peter, and Bernhard Siemon. "Advanced inversion methods for airborne electromagnetic exploration." GEOPHYSICS 65, no. 6 (November 2000): 1983–92. http://dx.doi.org/10.1190/1.1444882.

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Airborne electromagnetic (AEM) surveys can contribute substantially to geologic mapping and target identification if good‐quality multifrequency data are produced, properly evaluated, and displayed. A set of multifrequency EM data is transformed into a set of apparent resistivity ([Formula: see text]) and centroid depth ([Formula: see text]) values, which then are plotted as a sounding curve. These [Formula: see text] curves commonly provide a smoothed picture of the vertical resistivity distribution at the sounding site. We have developed and checked methods to enhance the sensitivity of sounding curves to vertical resistivity changes by using new definitions for apparent resistivity and centroid depth. One of these new sounding curves with enhanced sensitivity to vertical resistivity contrasts is plotted from [Formula: see text] [Formula: see text] values derived from differentiation of the [Formula: see text] curve with respect to the frequency f. This approach is similar to the Niblett‐Bostick transform used in magnetotellurics. It not only enhances vertical changes in resistivity but also increases the depth of investigation. Sounding curves can be calculated directly from EM survey data and can be used to generate a resistivity‐depth parasection. Based on such a section, it can be decided whether a Marquardt‐type inversion of the AEM data into a 1-D layered half‐space model is adequate. Each sounding curve can be transformed into an initial step model of resistivity as required for the Marquardt inversion. We have inverted data from sedimentary sequences with good results. For data from a dipping conducting layer and a dipping plate, we have found that the results depend on the right choice of the starting model, in which the number of layers should be large rather than too small. Complex resistivity structures, however, often are represented better by using the sounding‐curve results than with the parameters of a layered half‐space.
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He, Jiao Long, Shu Guang Chen, and Xin Sheng Zhang. "Research on Technology of Highway Curve and Slope Road Segment Alignment Safety Design." Applied Mechanics and Materials 204-208 (October 2012): 1665–68. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.1665.

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In the paper, Combination curved with slope road segment on the driving experiment , The paper is analyzed the curve and slope road segment on Gradient, Horizontal Curve Radius, Speed and heart rate these variables of the inherent relation and law. The model of the relationship of the longitudinal slope and horizontal curve radius and heart rate is set up. By employing regression analysis, Conduct quantitative analysis, calculation and can be determined by the minimum horizontal curve radius value of vertical slope corresponding to at different vehicle-speeds on curved with longitudinal slope,Theoretical reference is provided for designers in the design technology research.
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He, Zhiming, and Qingjun Chen. "Vertical Seismic Effect on the Seismic Fragility of Large-Space Underground Structures." Advances in Civil Engineering 2019 (April 7, 2019): 1–17. http://dx.doi.org/10.1155/2019/9650294.

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The measured vertical peak ground acceleration was larger than the horizontal peak ground acceleration. It is essential to consider the vertical seismic effect in seismic fragility evaluation of large-space underground structures. In this research, an approach is presented to construct fragility curves of large-space underground structures considering the vertical seismic effect. In seismic capacity, the soil-underground structure pushover analysis method which considers the vertical seismic loading is used to obtain the capacity curve of central columns. The thresholds of performance levels are quantified through a load-drift backbone curve model. In seismic demand, it is evaluated through incremental dynamic analysis (IDA) method under the excitation of horizontal and vertical acceleration, and the soil-structure-interaction and ground motion characteristics are also considered. The IDA results are compared in terms of peak ground acceleration and peak ground velocity. To construct the fragility curves, the evolutions of performance index versus the increasing earthquake intensity are performed, considering related uncertainties. The result indicates that if we ignore the vertical seismic effect to the fragility assessment of large-space underground structures, the exceedance probabilities of damage of large-space underground structures will be underestimated, which will result in an unfavorable assessment result.
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Liu, Jingjing. "Anatomy of Gaudi's Curve Architectural Language." Journal of Arts and Humanities 6, no. 7 (July 20, 2017): 33. http://dx.doi.org/10.18533/journal.v6i7.1204.

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<p>Gaudi was a unique architectural designer at the aspect of architectural design in Art Nouveau. His architectural design has a unique line design, including the external shape curve of Casa Mila being representative. The external shape design of Casa Mila had subverted the external design of traditional architectures. The wave shape of its vertical wall had broken the contemporary traditional aesthetic consciousness of architectures. Thus, the reasons and effects for the curved shape in the external shape design of Casa Mila showing incisively and vividly how subversive and disruptive Casa Mila being are the source of studying its external curve design. During the same period, many architectural designs were also applied to curves in the external shape of the buildings. Therefore, the external shape of curves on Casa Mila is how its architectural design curves standing out are contrasted by curve design applied to other contemporaneous architectures in the period of Art Nouveau. The view of this paper expounds the reason that the curvilinear design of Casa Mila is different from that of other architectures, and the influence of the curvilinear design of Casa Mila in the period of Art Nouveau. This paper starts with the analysis of the architectural curve of Casa Mila. By comparative analysis of curve profile and its curvature in external modeling of "House of the People" and Tassel Hotel, this paper reveals that Gaudi's architectural features have an unique external modeling and conveys that the architectural curve of external shape more abounds in using natural elements of imitation.</p>
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38

Hassan, Yasser, and Said M. Easa. "Sight distance red zones on combined horizontal and sag vertical curves." Canadian Journal of Civil Engineering 25, no. 4 (August 1, 1998): 621–30. http://dx.doi.org/10.1139/l97-127.

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Coordination of highway horizontal and vertical alignments is based on subjective guidelines in current standards. This paper presents a quantitative analysis of coordinating horizontal and sag vertical curves that are designed using two-dimensional standards. The locations where a horizontal curve should not be positioned relative to a sag vertical curve (called red zones) are identified. In the red zone, the available sight distance (computed using three-dimensional models) is less than the required sight distance. Two types of red zones, based on stopping sight distance (SSD) and preview sight distance (PVSD), are examined. The SSD red zone corresponds to the locations where an overlap between a horizontal curve and a sag vertical curve should be avoided because the three-dimensional sight distance will be less than the required SSD. The PVSD red zone corresponds to the locations where a horizontal curve should not start because drivers will not be able to perceive it and safely react to it. The SSD red zones exist for practical highway alignment parameters, and therefore designers should check the alignments for potential SSD red zones. The range of SSD red zones was found to depend on the different alignment parameters, especially the superelevation rate. On the other hand, the results showed that the PVSD red zones exist only for large values of the required PVSD, and therefore this type of red zones is not critical. This paper should be of particular interest to the highway designers and professionals concerned with highway safety.Key words: sight distance, red zone, combined alignment.
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39

Hall-Findlay, Elizabeth J. "A Simplified Vertical Reduction Mammaplasty: Shortening the Learning Curve." Plastic and Reconstructive Surgery 104, no. 3 (September 1999): 748–59. http://dx.doi.org/10.1097/00006534-199909010-00020.

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Hall-Findlay, Elizabeth J. "A Simplified Vertical Reduction Mammaplasty: Shortening the Learning Curve." Plastic and Reconstructive Surgery 104, no. 3 (September 1999): 760–61. http://dx.doi.org/10.1097/00006534-199909010-00021.

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41

Hall-Findlay, Elizabeth J. "A Simplified Vertical Reduction Mammaplasty: Shortening the Learning Curve." Plastic and Reconstructive Surgery 104, no. 3 (September 1999): 762–63. http://dx.doi.org/10.1097/00006534-199909010-00022.

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42

Hall-Findlay, Elizabeth J. "A Simplified Vertical Reduction Mammaplasty: Shortening the Learning Curve." Plastic & Reconstructive Surgery 104, no. 3 (September 1999): 748–59. http://dx.doi.org/10.1097/00006534-199909030-00020.

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43

Hammond, Dennis C. "A Simplified Vertical Reduction Mammaplasty: Shortening the Learning Curve." Plastic & Reconstructive Surgery 104, no. 3 (September 1999): 760–61. http://dx.doi.org/10.1097/00006534-199909030-00021.

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44

Spear, Scott L. "A Simplified Vertical Reduction Mammaplasty: Shortening the Learning Curve." Plastic & Reconstructive Surgery 104, no. 3 (September 1999): 762–63. http://dx.doi.org/10.1097/00006534-199909030-00022.

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45

Hawkins, H. Gene. "How Modern Headlamp Performance Impacts Sag Vertical Curve Design." Journal of Transportation Engineering 133, no. 4 (April 2007): 223–31. http://dx.doi.org/10.1061/(asce)0733-947x(2007)133:4(223).

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46

Bassan, Shy. "Vertical curve design insights of road tunnels versus highways." Journal of Transportation Safety & Security 9, no. 3 (July 13, 2016): 319–46. http://dx.doi.org/10.1080/19439962.2016.1206049.

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47

Carrigan, Christine E., and Malcolm H. Ray. "Proposed Horizontal Curve and Vertical Grade Encroachment Adjustment Factors." Transportation Research Record: Journal of the Transportation Research Board 2521, no. 1 (January 2015): 96–102. http://dx.doi.org/10.3141/2521-10.

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The probability of a vehicle encroaching onto the roadside is influenced by several geometric characteristics of the roadway. The horizontal curvature and vertical grade encroachment adjustment factors (EAFs) used in the third version of the Roadside Safety Analysis Program (RSAPv3) were adopted from adjustment factors introduced in 2003 in NCHRP Report 492 during the original development of RSAP. These adjustments were developed by interpreting earlier work on curves and grades. Given the weaknesses and limitations of the earlier study, it was suggested that a larger-scale study with larger sample size and more representative crash severities would be appropriate. This paper describes the development of new horizontal curve and vertical grade EAFs for rural areas. EAFs were developed from a cross-sectional model of crash data that controlled for geometric influences, traffic volumes, segment length, and highway type. The proposed EAFs are not identical to the current factors, which is not surprising, because the earlier study reviewed only 300 fatal crashes with fixed objects in 1975. This study reviewed the full range of crash severities and a range of run-off-road crash types and was conducted on much more recent crash data (2002–2010). Promisingly, however, EAFs are of the same order of magnitude and are broadly consistent with the earlier study.
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48

Zhang, Sheng Yun, Ji Long Tang, Zhi Peng Wei, Dan Fang, Xuan Fang, Xue Ying Chu, Fang Fang, Jin Hua Li, and Xiao Hui Ma. "New Method of Distinguishing X-Ray Diffraction Curves about Laser Structure." Advanced Materials Research 881-883 (January 2014): 1768–72. http://dx.doi.org/10.4028/www.scientific.net/amr.881-883.1768.

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Come up with a new method of rocking curves analysis, its using the software of the double-crystal X-ray diffraction rocking curves analysis to simulate vertical cavity surface emitting laser structure. Simulate the X-ray diffraction rocking curve of each part of laser structure, and then compare with the diffraction rocking curve of the overall structure in order to acquire the adscription of each diffraction peak, the method can also be applied to other semiconductor lasers. Compared with conventional PDF card library about diffraction position of all material peaks, the method has the advantages of fast and accurately to distinguish, high efficiency. In the end, the X-ray diffraction rocking curves analysis method is applied to the MOCVD growth of GaAs based vertical cavity surface emitting laser, and quoting strain relaxation mechanisms for explaining the reasons for the partial peak drifting.
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André, Yves. "Finitude des couples d'invariants modulaires singuliers sur une courbe algébrique plane non modulaire." Journal für die reine und angewandte Mathematik (Crelles Journal) 1998, no. 505 (December 16, 1998): 203–8. http://dx.doi.org/10.1515/crll.1998.505.203.

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Abstract Let S be an irreducible algebraic curve in the affine complex plane. Assume that S is neither a horizontal Une, nor a vertical line, nor a modular curve Y0(N) (for any integer N ≧ 1). Then there are only finitely many points P of S such that both coordinates of P are singular moduli (i.e. invariants of elliptic curves with complex multiplication).
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Azeem, Muhammad, Waheed Ul Hamid, Arfan Ul Haq, and Huma Ijaz. "Correlation between Von Spee’s Curve and Vertical Dental Eruptions in Class II Division-2 Malocclusion." Orthodontic Journal of Nepal 7, no. 2 (June 8, 2018): 24–27. http://dx.doi.org/10.3126/ojn.v7i2.20160.

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Introduction: Von Spee’s curve is one of the important treatment aspects in orthodontics. Any orthodontic treatment planning is dependent on this key factor.Objective: To find out the correlation between the Von Spee’s curve and occlusal eruption of anterio-posterior teeth in Class II Division 2 malocclusion.Materials & Method: Current research was conceived at the Department of Orthodontics, de’Montmorency College of Dentistry and Faisalabad Medical University. Two hundred and fifty Class II Division 2 patients (112 male, mean age: 15.1±1.5 years; 138 female, mean age: 15.4± 1.3 years) were included. Depth of the curve was calculated on lateral cephalograms and dental plaster models, and correlated with the vertical eruption of lower incisal teeth and posterior mandibular molars.Result: The mesiobuccal site of mandibular first molar was the deepest part of Von Spee’s curve, and vertical eruption of lower incisal teeth were more related to depth of Von Spee’s curve as compared to vertical eruption of mandibular molars.Conclusion: Vertical eruption of the mandibular molar teeth make significant contribution to the depth of Von Spee’s curve in Class II Division 2 malocclusion.
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