Horizontal Geometry Research Articles

Cenozoic crustal-scale duplexing and flat Moho in southern Tibet: Evidence from reflection seismology

Although the Lhasa terrane of southern Tibet is an integral part of the Tibetan plateau, how the area has achieved its current high altitude of ~5000 m remains poorly understood. This is largely due to the fact that little is known about deep (>15 km) crustal structures and the depth and geometry of the Moho below the terrane. In this study, we address this question by acquiring and analyzing high-resolution seismic reflection data gathered from four high-energy dynamite shots along a 137-km north-south traverse spanning the southern Lhasa terrane. Our new seismic data reveal the presence of north-dipping reflectors in the crust, a seismically weak-reflection layer at the lowermost crust, and a sub-horizontal and locally discontinuous Moho at depth of 69–72 km with a crustal velocity of 6.30 km/s. The discordant relationship between the crustal dipping reflectors, the subhorizontal lower crustal layer, and the flat Moho suggests that the ~12-km basal section of the Lhasa terrane crust is a decoupling zone accommodating different styles of lithospheric-scale deformation. Because the north-dipping reflectors can be projected and/or connected with the reflectors in the Cenozoic Himalayan thrust system and the southernmost Lhasa terrane, we propose that the dipping crustal reflectors are parts of a south-directed crustal-scale thrust duplex created by the Cenozoic India-Asia collision. The relatively discontinuous and horizontal geometry at the base of the crust indicates that the Moho was reconstituted through ductile deformation in the lowermost crust caused by abnormally high temperature.

Effects of Inter-Vehicle Interaction on Speed and Lateral Position for Reviewing Free - Flow Condition

Speed and lateral position of free-flowing vehicles are the performance measures of roadway geometric elements. Most of the earlier studies evaluated a threshold headway based free-flow criteria at an observation station and considered the relevant vehicles for estimation of speed and lateral position. However, evaluation of free-flow at one observation station cannot guarantee the same in the entire segment, due to the possible inter-vehicle interactions prior to the observation station. It can cause inappropriate performance evaluation of the roadway geometric element. Moreover, horizontal curve is one of the critical geometric elements of four-lane highways. Hence, in this research, all the possible inter-vehicle interactions of passenger cars prior to a curve center of four-lane divided highways were identified and analyzed for the effect of inter-vehicle interactions on speed and lateral position. The analysis indicates that speed and lateral position are dependent on the location of inter-vehicle interactions prior to a curve center. Vehicles, which did not interact with other vehicles until the curve center, remains uninfluenced and should be considered for geometric evaluation. This finding is useful to identify the relevant free-flowing vehicles and in-turn, improve the evaluation of horizontal curve geometry.

Planar Triode for Vacuum Microelectronics

The article studies a triode for vacuum microelectronics with horizontal geometry (planar triode). A simple theoretical model of the device is proposed and the minimum cutoff voltage is calculated. Experiments are carried out on the fundamental model of the device, which qualitatively confirm the main theoretical conclusions.

INVESTIGATION OF COUNTER-CURRENT FLOW LIMITATION FOR AIR-WATER IN A PWR HOT LEG EXPERIMENTAL LOOP FOR DIFFERENT GEOMETRY

Gas/liquid two-phase stratified flows in horizontal channels are frequently encountered in nuclear reactors, oil and gas pipelines, steam generators, refrigeration equipment, reflux condensers, packed columns, and heat pipes. The phenomenon known as countercurrent flow limitation, or flooding, is the limiting condition where the flow rates of neither the gas nor the liquid can be further increased without changing the flow pattern. This is the condition where the maximum air mass flow rate at which the down-flowing water mass flow rate is equal to the inlet water mass flow rate. This limiting condition, also known as onset of flooding, can occur in vertical or horizontal geometry. This work is a review of recent experimental investigations of countercurrent flow limitation (CCFL) for various hot-leg geometries of pressurized water reactors (PWRs). We compare results with those obtained from the Nuclear Technology Development Centre (CDTN) in 2005. Recent experimental results in the literature are in good agreement with the 2005 findings.

Soil and Crop Variability Induced Management Zones to Optimize Potato Tuber Yield

Highlights Economy of Atlantic Canada relies on export of potatoes; Prince Edward Island stands first in potato production. Soil variability adversely affects potato tuber yield and requires precision management of potato fields. Precision agriculture promotes establishing soil management zones to mitigate effects of soil variability. This study quantifies soil variability and establishes soil management zones to optimize potato tuber yield. Abstract. Soil variability and the resultant lower potato tuber yield can be mitigated through precision agricultural practices. This study quantified variability of soil and crop properties to construct management zones (MZs) for optimizing tuber yield. Soil was sampled from each grid and analyzed for soil chemical properties. Time Domain Reflectometry (TDR), DualEM-2 sensor, and normalized difference vegetation index (NDVI) meter were used to collect each grid‘s soil water content (θ), horizontal coplanar geometry (HCP) of the apparent ground electrical conductivity, and NDVI, respectively at various plant growth stages during the cropping season of 2018. Most of the parameters had moderate to high variability in both fields. Tuber yield was 34% higher in Field 1 partly due to two and a half times higher phosphorous (P) and iron (Fe) contents in its soil than yield of Field 2. The other inflicting factor for higher yield in Field 1 included higher %P/Al (P aluminum ratio) of soil of Filed 1 than Field 2. The soil and crop variability data helped establishing MZs that can facilitate site-specific precision nutrient management for improving soil fertility and optimizing potato tuber yield.

S-Shaped Transition Curves as an Element of Reverse Curves in Road Design

A road designing involves horizontal and vertical alignment. The horizontal geometry is formed by straight and curvilinear sections that are traditionally formed using circular and transition curves (mainly the clothoid). Different geometric systems that are designed using circular and transition curves are between others circular curves with symmetrical or unsymmetrical clothoids, combined curves, oval curves and reverse curves. Designing these systems is quite complex. Therefore, so-called S-shaped transition curves are an alternative to traditional approaches. These curves are known from literature and are modern geometric tools for the shaping of reverse curves. The paper analyses the basic geometric properties of these curves as well as compare to the geometry of the appropriate geometric systems, which are formed with clothoid or using S-shaped transition curves. In addition, a procedure for designing reverse curves using S-shaped transition curves was proposed. Another research topic was the comparison of the analysed reverse curves (created using polynomial transition curves) with traditional curves (created using the clothoid). The results of the studies, despite the noticeable differences in the geometry of the compared components, confirm the practical usefulness of the S-shaped transition curves for designing the geometry of the route.

Effect of horizontal curve geometry on vehicle speed distribution: a four-lane divided highway study

ABSTRACT Poor coordination between geometric elements of horizontal curves can lead to unsafe speed. This study evaluated the effect of horizontal curve geometry on vehicle speed distribution for a four-lane divided highway and developed prediction models for mean speed and standard deviation. Spot speed data of passenger cars (PC), heavy commercial vehicles and light commercial vehicles were collected at 24 horizontal curves. Statistical analysis of the speed data of randomly selected 10 sites revealed PC as the critical vehicle category. Hence, the effects of horizontal curve geometry on PC speed were analyzed and radius was identified as the most influencing parameter. Radius beyond 400 m had similar influence on speed distributions. Appropriate models were developed using regression analysis. Degree of curvature was found as the most significant predictor. Benefits of the proposed models over traditional 85th percentile speed in designing and evaluating horizontal curves for consistency and safety were discussed.

Deciphering channel networks from aeromagnetic potential field data: the case of the North Sea Quaternary tunnel valleys

Summary High-resolution magnetic data and potential field methods have been used to perform a detailed analysis of networks of late Quaternary subglacially-cut tunnel valleys (central Viking Graben, Norwegian sector of the North Sea). High-frequency, ribbon-like, sinuous, paired magnetic anomalies interpreted to be the signature of tunnel valleys are identified. Such magnetic anomalies have 1 to 8 nT amplitudes and reflect a magnetic susceptibility contrast between valley infills and the host sediments. Fractional vertical derivative and horizontal gradient transforms provide the best control on the accurately delineation of tunnel valleys by plotting automatically the extrema. The 2D forward modelling is a very effective approach to determinating the geometric parameters and magnetic susceptibility of the modeled valleys. It allows to determine the finite-width flat horizontal thin geometry as the most appropriate simple geometry to simulate the magnetic anomaly linked to a channel structure. The application of Euler deconvolution using complex algebra allows to substantiate the structural index (n = 1.5) for simple palaeovalley geometries and to determine fair valley depth estimates.

Railway geometric design based on satellite imagery and digital terrain model

The purpose of research were (1) a conceptual, functional model designed and implementation for railway geometric design, (2) standard operational procedure made for railway geometric design using satellite imagery and digital terrain model, (3) calculated geometric information on the railway route so that fulfilling geometric national and international standard, (4) horizontal alignment drawing presented on the railway route, (5) vertical alignment drawing presented on the railway route. This research uses a descriptive method. Study location in South Sumatra Province, Indonesia. July 2016 to January 2017 is when conducting research. Calculation of horizontal and vertical geometry information using spatial analysis. Horizontal and vertical geometric calculated on railway route based on satellite image and digital terrain model could be faster, easier and cheaper than terrestrial and analog method.

Effect of nozzle exit shape on the geometrical features of horizontal turbulent jet flame

The accidental releases of high pressure gas fuel could lead to the jet fires, resulting in a serious of disastrous events. This paper presents a systematical investigation upon the effect of nozzle exit shape on the horizontal jet flame geometry by experiments. The nozzles of circular, rectangular, equilateral triangle and elliptic exits were used for experimental tests. New correlations for the horizontally projected flame length, vertically projected flame height and lift-off distance are established for horizontal jet fires ejected from the exits of different shapes. The exit shape coefficient (the ratio of hydraulic to equivalent diameters) is found to dominate the phenomenological constant in the classic correlation of flame length, and the dependency of phenomenological constant on exit shape coefficient is quantified. It is also clarified that Richardson number (the ratio of flame buoyancy to exit momentum) dominates the ratio of vertically projected flame height to horizontally projected flame length. The hydraulic diameter is proposed to revise the dimensionless flow number, for physically addressing the effect of exit shape on the lift-off distance of horizontal jet flame.

Effect of Horizontal Curve Geometry on the Maximum Speed Reduction: A Driving Simulator-Based Study

Operating speed reduction models can be used to evaluate the geometric design consistency. The proposed study developed a maximum speed reduction model for drivers habituated in weak lane disciplined driving conditions. The required experiment was carried out on a fixed-base driving simulator. The speed profiles of 48 participating drivers along 24 different tangent-curve configurations were recorded. The maximum speed at the preceding tangent and the minimum speed in the following curve were used to estimate the maximum speed reduction (MSR) of each subject driver. A multiple regression model was developed for the obtained 85th percentile maximum speed reduction data and the road geometric parameters such as radius, curvature, preceding tangent length, curve length, gradient, shoulder width, and extra-widening. The developed model identified curvature (i.e., the inverse of radius) and preceding tangent length as predictor variables. Based on the obtained results, a nomogram for road geometric safety evaluation is proposed in the paper.

A Statistical Study of the Magnetic Imprints of X-class Solar Flares

Abstract Magnetic imprints, the rapid and irreversible evolution of photospheric magnetic fields as feedback from flares in the corona, have been confirmed by many previous studies. These studies showed that the horizontal field will permanently increase at the polarity inversion line (PIL) after eruptions, indicating that a more horizontal geometry of the photospheric magnetic field is produced. In this study, we analyze 20 X-class flares since the launch of the Solar Dynamics Observatory in 15 active regions with heliographic angles no greater than 45°. We observe clear magnetic imprints in 16 flares, whereas 4 flares are exceptional. The imprint regions of the horizontal field are located not only at the PIL but also at sunspot penumbra with strong vertical fields. Making use of the observed mass and speed of the corresponding coronal mass ejections (CMEs), we find that the CMEs with larger momenta are associated with stronger magnetic imprints. Furthermore, a linear relationship, with a Kendall’s Tau-b coefficient 0.54, between the CME momentum and the change of Lorentz force, is revealed. Based on that, we quantify the back reaction time to be ∼70 s, with a 90% confidence interval from about 50 to 90 s.

Study of Flow Rate Measurements Derived from Temperature Profiles of an Emulated Well by a Laboratory Prototype.

The objective of this work is the study of the procedure for flow rate measurement derived from temperature profiles. This method is deemed appropriate because of the inability to mount conventional flow meters in multiple-zone oil wells. In this work, a reduced-scale prototype well with horizontal geometry was developed to study and validate a method of flow profiling by temperature measurements in the well column based on a heat transfer mathematical model studied by Ramey in 1962. Flow sensors were installed at key points to provide validation data for the flow measurements derived from the temperature. The plant was automated and all the tests were managed from a workstation. It was possible to test different situations to provide a variability of evaluation scenarios. The initial experiments used injected fluid flow rates of 15 and 18 L/min in the well inlet. The results of the calculated flow values in different work conditions were compared with a relatively low error reference meter.

Trends in the variability of potato tuber yield under selected land and soil characteristics

The objective of this study was to evaluate variations in potato tuber yield with the selected land and soil characteristics including (i) topography (elevation and slope); (ii) geometry (horizontal coplanar geometry (HCP)and perpendicular coplanar geometry (PRP)); (iii) hydrology (volumetric moisture content; θv), and (iv) chemistry (phosphate, potash, organic carbon; organic carbon and pH). Analyses of the data collected across four potato fields, two each in Prince Edward Island and New Brunswick (NB), showed that the tuber yield negatively correlated with the field slope and positively correlated with most of the soil characteristics studied. Field elevation affected yield only under certain conditions such as higher range of elevation (≥ 7 m) (Field 2 in NB). Among soil characteristics, only HCP and PRP correlated with field elevation. The slope and elevation explained 22% to 36% variability of yield. Investigations of yield and topography by zonal analysis showed that yield was lower in zones of higher slope or elevation and lower θv, as the mean θv decreased in zones with a higher slope.

Channel identification using 3D seismic attributes and well logging in lower Shihezi Formation of Hangjinqi area, northern Ordos Basin, China

Channel identification in oil and gas exploration is a vital task due to the importance of fluvial reservoirs. The fluvial sandstone of Lower Shihezi Formation of Ordos Basin is the primary target layer of gas exploration and development which has the maximum potential of producing tight gas sand reservoir in China. Fluvial paleo-channels can be identified easily by core, outcrop and logs data, but due to development of the several faults and limited seismic resolution in the study area, it is difficult to identify them by conventional seismic methods. The study was conducted in Hangjinqi area on the regional level of about 4537.87 km2. The radical objective of this research is to recognize the horizontal distribution and geometry of the multiple channels. Based on the study of integrated analyses of geological cores, geophysical well-logs, and seismic attributes it is confirmed that multiple braided channels are present in the study area. Channel distribution based on seismic attributes and its overlapping on the paleogeographic map showed that the channels are coming from the North and are merging towards South direction.

The Muskat problem in two dimensions: equivalence of formulations, well-posedness, and regularity results

In this paper we consider the Muskat problem describing the motion of two unbounded immiscible fluid layers with equal viscosities in vertical or horizontal two-dimensional geometries. We first prove that the mathematical model can be formulated as an evolution problem for the sharp interface separating the two fluids, which turns out to be, in a suitable functional analytic setting, quasilinear and of parabolic type. Based upon these properties, we then establish the local well-posedness of the problem for arbitrary large initial data and show that the solutions become instantly real-analytic in time and space. Our method allows us to choose the initial data in the class $H^s,$ $s\in(3/2,2)$, when neglecting surface tension, respectively in $H^s,$ $s\in(2,3),$ when surface tension effects are included. Besides, we provide new criteria for the global existence of solutions.

Influence of Road Geometry on Driver’s Gaze Behavior on Motorways

Driver’s gaze is a highly selective dynamic process, which ensures a precise perception of moving objects, speeds and spatial expansions in road traffic. Thus, the gaze behavior of drivers determines largely their driving behavior, and is crucial for traffic safety. With the aid of modern technology, the gaze behavior can be precisely recorded during driving. This paper describes part of the research, which has been undertaken in order to investigate the relationship between driver’s gaze behavior and horizontal alignment geometry. It is known, that driver’s stress state and gaze concentration are not the same when steering a vehicle along straight stretches and within curves. The stress is higher in curves and this leads to an increased attention. The gaze behavior in left and right horizontal curves is characterized by certain gaze patterns, which clearly differ from each other. In this respect, appropriate investigations and analyzes have been also carried out. Different parameters have been calculated in order to assess and quantify the gaze behavior. By evaluating these parameters, the spatial and temporal concentration of the driver’s gaze as well as the intensity of information acquisition and processing have been analyzed along straight stretches, left and right horizontal curves.

Improving GIS-based models for bicycling speed estimations

For reasons ranging from public health to sustainable urban development, traffic planning as well as urban design aim to increase bicycling at the cost of fossil fuel-based transport. Despite this increasing interest in bicycling, most planning practices handle bicycling schematically, applying methods that rely on fixed speed templates, paying little attention to how bicycling speeds vary depending on bicycle routes and the contexts of routes. Since travel time is essential for travel mode and route choice, more refined methods for predicting bicycling speeds should be highly useful. This paper presents a model that combines variables from two recent bikeability modelling studies. One is an urban form-based study that identified a set of variables significant for bicycling speeds. The other, based on so-called Markov-modelling for grasping speed dependence between contiguous road segments, estimates speed based on horizontal and vertical geometry of routes, and provides very detailed and continuous speed profiles along entire routes. The new combined model is estimated using GPS tracking of real bicycle trips in combination with GIS-based data of the bicycle route networks. The covariates included in the model are route geometry, intersection impedance, type of bicycle-route, kind of surface, and density of entrances to buildings along route. The latter is a proxy for slower bicycling due to vibrant urban context. The new model results in more detailed and realistic speed estimations than the previous models. This paper presents the model and some results from applying the model on bicycle routes in Gothenburg.

Technical Note: Influence of entrance window deformation on reference dosimetry measurement in various beam modalities.

Phantoms for horizontal beam geometry can avoid issues in vertical-beam geometry, such as change in chamber depth due to evaporation, and defining the origin at the water surface. However, their thin entrance windows would deform when these phantoms are filled, which can change the chamber depth, as pointed out by The International Atomic Energy Agency (IAEA) TRS-398. Currently, few reports (Arib etal., J Appl Clin Med Phys. 2006; 7:55-64, and Kinoshita etal., Rep Pract Oncol Radiother. 2018; 23:199-206) are available with practical data on window deformation. Therefore, we investigated the influence of entrance window deformation on chamber depths in water phantoms and the measurements in various beam modalities. To examine widely used phantoms and phantoms with different characteristics, three phantom types were investigated (the number of phantoms investigated appears in parentheses): PTW-type 41023 (2), Qualita-QWP-04 (2), and IBA-WP34 (2). Prior to the investigation, these phantoms were stored for acclimatization in a room for approximately 10h under the following two conditions: (a) room temperature: 21±2°C; (b) room temperature: 27±2°C. Using a dial indicator, the centers of the windows were monitored every 30min for 12h immediately after the phantoms were filled, in a treatment room at the room temperature of 21±2°C. Immediately after the phantoms were filled, the window deformation ranged from -0.07 (inward-deformation) to 0.3mm (outward deformation) among the six phantoms, in comparison with empty phantom windows. For 12h after the phantoms were filled, the change in the deformation was up to 0.23mm, but typically less than 0.15mm. Reference dosimetry in photon, electron, and proton beams would not be influenced significantly by these window behaviors, whereas the window deformation has a slight impact on those heavy ion beams.

Effect of Finned-Tube on the Enhancement of Melting Process of PCM in Eccentric Cylinders

Abstract The process of melting of a phase-change material (PCM) in eccentric horizontal cylinders geometry is studied numerically. Numerical simulations are performed for symmetric melting of phase change material between the two cylinders using the finite volume method. The inner cylinder is a finned-tube to enhance the heat transfer between the inner cylinder and the PCM. Inner cylindrical is considered as hot wall while outer is insulated. These simulations show the melting process from the beginning to the end. As result, it is found that the use of fins on the inner tube increases the melting process by decreasing the time of melting by 72.72 %.