Exit Arm Research Articles

Statistical modeling of traffic noise at intersections in a mid-sized city, India

Abstract The modeling of traffic noise is more debated around intersections due to traffic flow and road geometry complexity. The available intersection-specific traffic noise models cannot be transferred to predict the traffic noise at intersections in the mid-sized Indian cities due to traffic heterogeneity, variety in driving conditions, and vehicle compositions. This article aims to develop an intersection-specific traffic noise model by collecting data at 19 intersections in Kanpur, India. The data include a wide range of traffic, road, and weather-related variables. Furthermore, significant input variables are determined and used in the statistical regression model to develop an intersection-specific traffic noise model for the mid-sized Indian cities. This study develops a separate entrance and exit arm model based on the corresponding influencing variables. The coefficient of determination (R 2) value is 0.74 and 0.69 for the developed model at the entrance and exit arms, respectively, whereas these models achieve R 2 values of 0.73 and 0.67 in the validation step. Also, the performance of developed models is evaluated on the standard and mean absolute errors as performance metrics. This study finds that traffic volume and receiver distance are relatively the most important variables in the entrance and exit arm noise models.

A new method to suppress high-order harmonics for a synchrotron radiation soft X-ray beamline**Supported by National Natural Science Foundation of China (11375227, 61204008)

A feasible and convenient method is proposed to suppress higher-harmonics for a varied-line-spacing plane grating monochromator in the soft X-ray region. Related calculations and experiments demonstrate that decreasing the included angle slightly by changing the parameter of the exit arm length can significantly improve light purity. This method is suitable and has been used for experiments of detector calibration in beamline 4B7B at the Beijing Synchrotron Radiation Facility (BSRF).

Hook Turns as a Solution to the Right-Turning Traffic Problem

In traffic systems where driving is on the left, right-turning movements tend to be difficult to efficiently accommodate at signal controlled junctions. A hook turn is one potential solution for this. A hook turn is where a right turn is made from the nearside lane rather than an offside lane at a four-leg signalised junction. After entering the junction, the turning vehicle waits at a nearside position in front of the side road stop line, and then proceeds toward the exit arm when the side road signal turns green. The research described in this paper uses microscopic simulation modelling in an innovative way to compare the traffic performance of a hypothetical hook-turn junction with an equivalent conventional junction with opposed right turns. The simulation model evaluated traffic performance under various combinations of demand flow, turning proportions, and signal timings. It was found that hook turns reduced delays to through traffic from the same approach in nearly all cases. Overall junction performance depended on the scale of any increased delays to left-turning traffic and side road traffic resulting from the hook-turn movement. It is concluded that hook turns could be used much more widely than at present—including where driving is on the right—offering significant operational benefits in the right circumstances.

Micro-focusing of attosecond pulses by grazing-incidence toroidal mirrors

The design of optical systems for micro-focusing of extreme-ultraviolet (XUV) attosecond pulses through grazing-incidence toroidal mirrors is presented. Aim of the proposed configuration is to provide a micro-focused image through a high demagnification of the XUV source with the following characteristics: i) almost negligible aberrations; ii) long exit arm to easily accommodate at the output the experimental setups required for the applications of the focused attosecond pulses; iii) possibility to have an intermediate region where the XUV beam is collimated, in order to insert a plane split-mirror for the generation of two XUV pulse replicas to be used in a XUV-pump/XUV-probe setup. We present the analytical and numerical study of two optical configurations characterized by two sections based on the use of toroidal mirrors. The first section provides a demagnified image of the source in an intermediate focus that is free from defocusing but has a large coma aberration. The second section consists of a relay mirror that is mounted in Z-shaped geometry with respect to the previous one, in order to give a stigmatic image with a coma that is opposite to that provided by the first section. An example is provided to demonstrate the capability to achieve spot sizes in the 5-15 μm range with a demagnification higher than 10 in a compact envelope.

Sheep laterality

Turning preferences among 309 white-faced ewes were individually evaluated in an enclosed, artificially lit T-maze, followed by each ewe choosing either a right or left return alley to return to peers. Data recorded included time in the start box, time in the T-maze, exit arm chosen to leave the T-maze, and return alley. Right and left arms of the T-maze were chosen 65.7% and 34.3% of the time, respectively, while right and left return alleys were chosen 32.4% and 67.6%, respectively. Exit arm and return alley were not independently chosen (p<.0001), with observed counts being higher than expected under independence when ewes made the same choice for exit and alley (RR or LL turn patterns) and being lower than expected for alternating choices (RL or LR). Out of the 309 ewes, 28.2% and 30.1% chose RR and LL turn patterns, respectively, while 37.5% chose the RL turn pattern, but only 13 (4.2%) chose the LR turning pattern. Overall, ewes that initially turned right when presented a second turning opportunity had a slight preference to alternate their turning direction, while ewes that initially turned left tended to continue turning left when given another chance to turn. Exit arm and return alley laterality was not related (α=.05) to time of day the test was administered, ewe's age or genetics, most recent liveweight, or most recent shorn fleece weight. The mean time spent in the start box (21 s) was not related to exit arm (p=.947) or return alley (p=.779). Mean time (15 s) spent in the T-maze was not related to exit arm (p =.086) or return alley (p =.952). More research will be required to understand sheep turning laterality and how it can impact working facilities and research equipment.

Purely elastic flow asymmetries in flow-focusing devices

The flow of a viscoelastic fluid through a microfluidic flow-focusing device is investigated numerically with a finite-volume code using the upper-convected Maxwell (UCM) and Phan-Thien–Tanner (PTT) models. The conceived device is shaped much like a conventional planar “cross-slot” except for comprising three inlets and one exit arm. Strong viscoelastic effects are observed as a consequence of the high deformation rates. In fact, purely elastic instabilities that are entirely absent in the corresponding Newtonian fluid flow are seen to occur as the Deborah number ( De) is increased above a critical threshold. From two-dimensional numerical simulations we are able to distinguish two types of instability, one in which the flow becomes asymmetric but remains steady, and a subsequent instability at higher De in which the flow becomes unsteady, oscillating in time. For the UCM model, the effects of the geometric parameters of the device (e.g. the relative width of the entrance branches, WR) and of the ratio of inlet average velocities ( VR) on the onset of asymmetry are systematically examined. We observe that for high velocity ratios, the critical Deborah number is independent of VR (e.g. De c ≈ 0.33 for WR = 1), but depends non-monotonically on the relative width of the entrance branches. Using the PTT model we are able to demonstrate that the extensional viscosity and the corresponding very large stresses are decisive for the onset of the steady-flow asymmetry.

KCaF(CO3) from X-ray powder data

Numerical analysis of the conductance of quasi-particles (QPs) is presented for two-dimensional (2D) L-shaped bent quantum waveguide (LBQW) with the application of inhomogeneous magnetic fields and a semiconductor-superconductor (Sm-S) junction at the exit arm. A delta-function scattering potential is placed at the Sm-S interface to simulate the imperfectness of the Sm-S interface. The conductance of the QPs as a function of magnetic field strongly depends on normal or superconducting state of the material at Sm-S junction. The conductance displays increasing behavior at the beginning and then it exhibits oscillatory decay. This implies that the Andreev reflection (AR) plays an important role on the conductance. As increasing the magnetic field, the conductance is decreased accordingly as the normal reflection is significantly enhanced and meanwhile the AR becomes imperfect. We also reveal the effects of various physical and geometrical parameters of system on the conductance in detail. (C) 2004 Elsevier B.V. All rights reserved.

Andreev scattering in the L-shaped bent quantum waveguide with inhomogeneous magnetic fields and a semiconductor–superconductor junction at exit arm

Numerical analysis of the conductance of quasi-particles (QPs) is presented for two-dimensional (2D) L-shaped bent quantum waveguide (LBQW) with the application of inhomogeneous magnetic fields and a semiconductor–superconductor (Sm–S) junction at the exit arm. A δ-function scattering potential is placed at the Sm–S interface to simulate the imperfectness of the Sm–S interface. The conductance of the QPs as a function of magnetic field strongly depends on normal or superconducting state of the material at Sm–S junction. The conductance displays increasing behavior at the beginning and then it exhibits oscillatory decay. This implies that the Andreev reflection (AR) plays an important role on the conductance. As increasing the magnetic field, the conductance is decreased accordingly as the normal reflection is significantly enhanced and meanwhile the AR becomes imperfect. We also reveal the effects of various physical and geometrical parameters of system on the conductance in detail.

Chunking versus foraging search patterns by rats in the hierarchically baited radial maze.

Rats were exposed to a radial maze containing six black smooth arms and six wire-grid-covered arms and a striped 'exit arm' in experiment 1. The probability of a black or grid arm being baited (5/6 vs 1/6) with sunflower seeds was associated with its proximal cue for some rats (the Relevant Arm Cue group) but not for others (the Irrelevant Arm Cue group). All rats could terminate a trial and receive a highly preferred morsel of apple by entering the exit arm only after having sampled all six seed-baited arms. Relevant Arm Cue rats usually chose some arms from the more densely baited set before choosing an arm from the less densely baited set and made fewer reentries than Irrelevant Arm Cue rats. Although such clustered, higher choice accuracy in the Relevant Arm Cue group corresponds to human clustered, better recall of verbal items from lists hierarchically organized by categories, these rats did not similarly exhaustively retrieve items (arm locations). That is, when required to terminate a trial by entering the 'exit' arm for an apple morsel after having sampled all seed-baited arms, both groups were equally unable to withhold making nonrewarded premature exits. This nonexhaustive foraging search pattern was maintained in the next two experiments in which the radial maze was reduced to three black and three grid arms along with the striped 'exit' arm and in which black and grid arm cues were paired with number of seeds (eight or one) in an arm for Relevant Arm Cue rats. Although Relevant Arm Cue rats displayed perfect clustering by entering all eight-seeded arms before a one-seeded arm, they made more premature exits and reentries into eight-seeded arms in experiment 2 or when forced to enter all eight-seeded arms in experiment 3 than did Irrelevant Arm Cue rats. These foraging tendencies prevent accurate estimations of the amount of information (i.e., arm locations) rats can 'chunk'.

Spherical-grating monochromator with a variable-line-spaced grating for synchrotron radiation

An optical design for spherical-grating monochromators for application to synchrotron radiation is presented. High spectral and spatial performance is obtained with a spherical variable-line-spaced grating coupled to a spherical mirror with its tangential plane coincident with the grating's equatorial plane. The monochromator works without an entrance slit in an off-Rowland configuration with a fixed entrance arm and demagnification on the exit slit. The law for groove-space variation of the grating compensates for the main spectral aberrations; spectral focusing in an extended energy range is ensured by a slight change in the exit arm with translations of the order of a few tens of millimeters. The inclusion of a spherical mirror ensures focusing on a plane perpendicular to the plane of spectral dispersion. The ultimate resolution is limited by the slope errors of a single spherical surface. The layout is applied to the design of a high-resolution monochromator for the 1000-250-eV region.

A modified Seya–Namioka monochromator with improved light intensity transfer

A monochromator with improved focusing properties has been designed and constructed using a novel optical geometry based on the Seya–Namioka concept. The only optical elements used are a spherical grating and a cylindrical mirror mounted in the exit arm (within the Rowland circle), retaining the Seya–Namioka scanning simplicity while minimizing reflections. This optical system compensates for the astigmatism associated with spherical optics at large incidence angles (as in the Seya–Namioka geometry) shortening the effective vertical focal length and providing a single, tight focus. A method of constructing a similar apparatus for any given spherical grating is presented. Experiments involving coherent vacuum ultraviolet generation from harmonic mixing demonstrate the utility of the new design.

A monochromatized multiple energy laboratory UV source for k-space imaging

Abstract A laboratory set-up for ultraviolet (UV) photoelectron spectroscopy combining a high intensity UV source and a toroidal UV monochromator, both being commercially available, is described. The source is modified in order to maximize the solid angle collected by the monochromator. Scanning its exit arm length allows for the optimization of the photon intensity as well as the energy resolution by minimizing the defocus term only. By using several different gases such as He, Ne or H2 one obtains a powerful tool to sample extended regions in k-space. Fermi energy maps are presented for Cu(110) in the photon energy range from 10.2 to 48.3 eV. As a result of the variable photon energy an actual zooming into the well-known Shockley surface state is possible.

The modified SX-700 monochromator with a spherical focusing mirror: a configuration for -1 diffraction order

In this letter we will discuss the modified SX-700 monochromator with a spherical focusing mirror [Rev. Sci. Instr. 60 (1989) 1608] but working in the configuration of −1 diffraction order. The coma aberration can be kept very small with a much shorter exit arm than in the configuration of +1 diffraction order. The differences between the two cases are given.

Development of a beamline for photoelectron spectroscopy on INDUS-I

The proposed beamline is centred using a toroidal grating monchromator with three in situ interchangeable gratings to cover the photon wavelength range of 60 to 1600 Å. The monochromator has an entrance arm length of 1500 mm and an exit arm length of 2634 mm. It is preceded by a pre-mirror which accepts radiation with a horizontal and a vertical deflection of 10 and 5 mrad respectively. The glancing angle of the incidence on the mirror is 4.5°. The focus of the mirror is at a distance of 2000 mm from its centre where the entrance slit of the monochromator will be placed. The monochromatised beam is focussed by a post-mirror. The requisite optical parameters of pre- and post-mirrors of ellipsoidal and toroidal types have been worked out. The optical performance of the complete beamline has been evaluated by ray tracing taking into account various errors of optical surfaces. Further calculations for misalignment errors have been carried out showing the critical dependence of the resolution and the throughput on pre-mirror positioning. Based on the numerical studies the design of the pre-mirror chamber including mirror mount and its various kinematic motions in vacuum has been worked out and incorporated in the complete design. Presently, the beamline is under construction.

Study of different SX-700 monochromator designs for the undulator beamline (BL51) at MAX-lab

Different designs of the SX-700 plane grating monochromator have been investigated for the undulator beamline (51) by using analytical considerations and carrying out ray tracing calculations. The most important modifications of the original design are those where the ellipsoidal focusing mirror has been replaced by a plane elliptical or by a spherical mirror. A significant advantage of the spherical mirror is essentially better figure accuracies (±0.2 arcsec). This is partly compensated by the introduced coma aberration which, however, can be made small with rather long exit arm lengths (5–6 m). If the slope errors of the plane elliptical mirror can be made as small as 0.5 arcsec, the differences in the ultimate resolution are small between the plane elliptical and spherical designs and then the source size is the main factor.

A chromatic premirror system for a double-crystal monochromator

A premirror system consisting of a plane mirror and a sagittal cylindrical mirror is described, in which the energy cutoff is changed by selecting different optical coatings. By meridional bending of the cylindrical mirror the beam can either be focused onto the sample or at infinity, giving maximum brightness or maximum energy resolution, respectively. Beam movements due to crystal misalignment are reduced by a short exit arm and by beam position monitoring.

High flux VUV beamline for photochemical processing study at Photon Factory (abstract)

Recent progress in photochemical processing involving photochemical etching and photochemical vapor deposition are really remarkable and such processes become the most promising candidates as a next-generation VLSI fabrication technology. Thus the study to elucidate the reaction mechanism of the photochemical processing is of both fundamental and technological importance. In order to promote this study, we have designed and constructed a new beamline at Photon Factory (BL 12C). It consists of three major parts; a prefocusing mirror, a multilayer mirror monochromator, and a differential pumping system. A Pt-coated SiC toroidal mirror (Rh:0.539 m, Rv:490 m) is installed in a prefocusing mirror chamber (18.3 m from the source), accepts 5.0-mrad horizontal and 1.0-mrad vertical divergence of the synchrotron radiation, reflects it 3.8° upward, and focuses it onto the middle of the exit arm of the monochromator (32.3 m from the source). A multilayer mirror, which was designed and fabricated by Yamamoto et al., so as to get high reflectance around 100 eV of photon energy (see the preceding paper), is installed in the monochromator, steers SR beam downward, and selects photon energy by changing an incident angle. With this arrangement, a quasimonochromatic and bright beam is obtained in the energy region 80–100 eV. The output flux is expected to be ∼1015 photons/s⋅10% bw with 200-mA ring current.

Effects of selection delays on radial maze performance: Acquisition and effects of scopolamine

The effects of post-selection confinement (delays) on both the acquisition of performance and the response to the muscarinic blocker, scopolamine, were examined in an automated version of the eight arm radial maze. Long-Evans rats, exposed to post-selection delays of 0.5 sec (n = 4) or 100 sec (n = 4) during daily training trials did not differ in either the number of trials to acquire an accurate baseline of performace or in the amount of time required to obtain all eight food pellets. However, the pattern (delta-arm scores) of within-session arm selections demonstrated by the two groups of rats differed. Rats exposed to the 0.5 sec delay typically selected arms adjacent to arms from which they exited while rats exposed to the 100-sec delay were more likely to enter arms 2-removed from the exit arm. When scopolamine (0.03 to 1.0 mg/kg) was administered prior to testing, rats in the 100-sec delay group showed a greater reduction of accuracy and a larger increase in selection latency than rats in the 0.5-sec delay group. The differential effect of delay value on delta-arm scores was also eliminated in a dosage dependent manner with scopolamine. Schopolamine methylbromide (0.3 mg/kg) was found to have little effect on performance. In summary, the results indicate that the post-selection delay procedure is a sensitive and selective test for chemical-induced dysfunctioning of spatial memory in rats.

Design of a high throughput grazing incidence monochromator for surf II

Optimization and ray trace calculations have been completed for a high throughput, toroidal grating monochromator. Several unique features have been incorporated into the design. The instrument will use the electron beam as the entrance slit, taking advantage of the small vertical beam size and high brightness of SURF II. The grating will be placed as close as possible to the storage ring and will intercept 51 mrad of horizontal orbit and below 500 Å, the full vertical light output. Three different gratings will be used to cover the ranges 30–90, 80–200 and 150–600 Å. Normally, multiρating instruments vary only the grating ruling spacing to change ranges, keeping the toroid and monochromator geometries identical in the different ranges. This instrument will be optimized independently in each range using the optimum toroid and monochromator geometries. As a result, the exit arm length will change in going from the long to the middle wavelength range and the included angle will change from 162.2° to 173° in going to the shortest wavelength range.