Minimum-Width Parallelogram Annulus with Given Angles

2021 ◽  
Vol 15 (2) ◽  
pp. 78-83
Author(s):  
Sang Won Bae
Keyword(s):  
Minimum Width

The Restricted Arc-Width of a Graph

10.37236/1734 ◽  
2003 ◽  
Vol 10 (1) ◽  
Author(s):  
David Arthur
Keyword(s):  
Unit Circle ◽  
Single Point ◽  
Minimum Width ◽  
Graph Operations ◽  
Function Mapping

An arc-representation of a graph is a function mapping each vertex in the graph to an arc on the unit circle in such a way that adjacent vertices are mapped to intersecting arcs. The width of such a representation is the maximum number of arcs passing through a single point. The arc-width of a graph is defined to be the minimum width over all of its arc-representations. We extend the work of Barát and Hajnal on this subject and develop a generalization we call restricted arc-width. Our main results revolve around using this to bound arc-width from below and to examine the effect of several graph operations on arc-width. In particular, we completely describe the effect of disjoint unions and wedge sums while providing tight bounds on the effect of cones.

scholarly journals R-DFS: A Coverage Path Planning Approach Based on Region Optimal Decomposition

2021 ◽  
Vol 13 (8) ◽  
pp. 1525
Author(s):  
Gang Tang ◽  
Congqiang Tang ◽  
Hao Zhou ◽  
Christophe Claramunt ◽  
Shaoyang Men
Keyword(s):  
Path Planning ◽  
Google Earth ◽  
Simulation Experiments ◽  
Minimum Width ◽  
Coverage Path Planning ◽  
Optimal Paths ◽  
Planning Approach ◽  
Polygonal Area ◽  
Aerial Vehicle ◽  
Working Distance

Most Coverage Path Planning (CPP) strategies based on the minimum width of a concave polygonal area are very likely to generate non-optimal paths with many turns. This paper introduces a CPP method based on a Region Optimal Decomposition (ROD) that overcomes this limitation when applied to the path planning of an Unmanned Aerial Vehicle (UAV) in a port environment. The principle of the approach is to first apply a ROD to a Google Earth image of a port and combining the resulting sub-regions by an improved Depth-First-Search (DFS) algorithm. Finally, a genetic algorithm determines the traversal order of all sub-regions. The simulation experiments show that the combination of ROD and improved DFS algorithm can reduce the number of turns by 4.34%, increase the coverage rate by more than 10%, and shorten the non-working distance by about 29.91%. Overall, the whole approach provides a sound solution for the CPP and operations of UAVs in port environments.

Sidewalk Static Obstructions and Their Impact on Clear Width

2021 ◽  
pp. 036119812199183
Author(s):  
Nicholas A. Coppola ◽  
Wesley E. Marshall
Keyword(s):  
Remote Sensing ◽  
Americans With Disabilities Act ◽  
Minimum Width ◽  
Street Furniture ◽  
Gis Methods ◽  
Pedestrian Accessibility

Data on sidewalks have long been deficient. But advances in remote sensing are beginning to increase data prevalence and accuracy. These sidewalk datasets rarely, if ever, account for static obstructions in the sidewalk such as signs, street furniture, or trees. This paper seeks to determine how much of a difference accounting for static obstructions will make when measuring the clear width of sidewalks. We extracted the minimum width of sidewalk surfaces—both with and without accounting for static obstructions—for the entirety of Cambridge, MA, using new GIS methods described in this paper. We then compared these results against Americans with Disabilities Act (ADA) standards for clear width as well as national and federal sidewalk guidelines. The results suggest a significant decrease in the average clear width of sidewalks when accounting for static obstructions. More specifically, the clear width of the average sidewalk drops from 4.5 ft (1.4 m) to 3.5 ft (1.1 m). The percentage of sidewalk segments meeting the 3-ft ADA standard drops from 78% to 51% when accounting for static obstructions. For the proposed 4-ft (1.2-m) ADA standard, it plunges from 59% of sidewalk segments meeting the width threshold to 31%. These results demonstrate that not accounting for static obstructions could lead to a gross overestimation of seemingly adequate sidewalks and an unrealistic assessment of sidewalk infrastructure and pedestrian accessibility.

scholarly journals Metallurgical and Mechanical Research on Dissimilar Electron Beam Welding of AISI 316L and AISI 4340

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
A. R. Sufizadeh ◽  
S. A. A. Akbari Mousavi
Keyword(s):  
Electron Beam ◽  
Electron Beam Welding ◽  
Weld Zone ◽  
Tensile Tests ◽  
Beam Current ◽  
Aisi 316L ◽  
Cooling Rates ◽  
Minimum Width ◽  
Optimum Sample ◽  
Aisi 4340

Dissimilar electron beam welding of 316L austenitic stainless steel and AISI 4340 low alloy high strength steel has been studied. Studies are focused on effect of beam current on weld geometry, optical and scanning electron microscopy, X-ray diffraction of the weld microstructures, and heat affected zone. The results showed that the increase of beam current led to increasing depths and widths of the welds. The optimum beam current was 2.8 mA which shows full penetration with minimum width. The cooling rates were calculated for optimum sample by measuring secondary dendrite arm space and the results show that high cooling rates lead to austenitic microstructure. Moreover, the metallography result shows the columnar and equiaxed austenitic microstructures in weld zone. A comparison of HAZ widths depicts the wider HAZ in the 316L side. The tensile tests results showed that the optimum sample fractured from base metal in AISI 316L side with the UTS values is much greater than the other samples. Moreover, the fractography study presents the weld cross sections with dimples resembling ductile fracture. The hardness results showed that the increase of the beam current led to the formation of a wide softening zone as HAZ in AISI 4340 side.

Effect of Vaned Diffuser on a Modified Turbocharger Centrifugal Compressor Performance

2014 ◽  
Vol 663 ◽  
pp. 347-353
Author(s):  
Layth H. Jawad ◽  
Shahrir Abdullah ◽  
Zulkifli R. ◽  
Wan Mohd Faizal Wan Mahmood
Keyword(s):  
Centrifugal Compressor ◽  
Numerical Study ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Width Ratio ◽  
Outlet Section ◽  
Suction Surface ◽  
Vaned Diffuser ◽  
Minimum Width

A numerical study that was made in a three-dimensional flow, carried out in a modified centrifugal compressor, having vaned diffuser stage, used as an automotive turbo charger. In order to study the influence of vaned diffuser meridional outlet section with a different width ratio of the modified centrifugal compressor. Moreover, the performance of the centrifugal compressor was dependent on the proper matching between the compressor impeller along the vaned diffuser. The aerodynamic characteristics were compared under different meridional width ratio. In addition, the velocity vectors in diffuser flow passages, and the secondary flow in cross-section near the outlet of diffuser were analysed in detail under different meridional width ratio. Another aim of this research was to study and simulate the effect of vaned diffuser on the performance of a centrifugal compressor. The simulation was undertaken using commercial software so-called ANSYS CFX, to predict numerically the performance charachteristics. The results were generated from CFD and were analysed for better understanding of the fluid flow through centrifugal compressor stage and as a result of the minimum width ratio the flow in diffuser passage tends to be uniformity. Moreover, the backflow and vortex near the pressure surface disappear, and the vortex and detachment near the suction surface decrease. Conclusively, it was observed that the efficiency was increased and both the total pressure ratio and static pressure for minimum width ratio are increased.

Use of roadside remnants of softwood scrub vegetation by birds in south-eastern Queensland

1993 ◽  
Vol 20 (2) ◽  
pp. 233 ◽  
Author(s):  
GJ Leach ◽  
HF Recher
Keyword(s):  
Management Practices ◽  
Bird Community ◽  
Vegetation Diversity ◽  
Minimum Width ◽  
Canopy Density ◽  
South Eastern ◽  
Roadside Vegetation ◽  
Length Width ◽  
Tree Component

Birds in roadside and remnant patches of vegetation in the Marburg district of south-eastern Queensland were studied from November 1989 to February 1990. Effects of the length, width and height of the tree, shrub and herb layers, and their major components, on the bird community were determined. In all, 43 species of birds were observed in roadside vegetation; 16 of these were abundant and widely distributed. Silvereyes were most frequently observed (240 observations), followed by superb fairy-wrens (59), yellow thornbills (53), double-barred finches (26), red-backed fairy-wrens (25) and Lewin's honeyeaters (20). Apart from silvereyes (20-654 of observations), and superb fairy-wrens on two roads (12 and 13%) and yellow thornbills on one (15%), no other species constituted more than 10% of observations on any road. In all, 48 species of birds were observed in remnant patches of vegetation, 14 in all of them. Rates of detection in remnant patches ranged from 2.7 to 5.3 birds per 5 min compared with a mean maximum rate for roadside vegetation of 1.3. The richness of the roadside avifauna increased significantly (P=0.001) as the volume (length x width x height) of the tree component, especially the softwood species, increased. The diversity of tree species in softwood remnants and the greater canopy density appear to be important factors that enhance the bird community. The number of birds was also correlated (P=0.05) with the volume of brigalow, Acacia harpophylla. The correlation of the volume of woody weeddshrubs with the number of birds was low (P=0.05), and with the number of species not significant, even though woody weeds were a major component of roadside vegetation. Although supporting fewer birds than remnant patches of vegetation, roadside vegetation contributes importantly to conservation of the avifauna in the Marburg district. Some simple management practices, such as maintaining a minimum width of undisturbed vegetation and retaining vegetation diversity, would ensure or enhance the long-term conservation benefits. Opportunities to regenerate softwood remnants could also be taken, particularly to enhance the value, and possibly prolong the life, of the associated remnants of brigalow.

Influence of High Duty Ratio and Frequency in WECM Employing In Situ Fabricated Wire Electrode

2017 ◽  
Vol 5 (4) ◽  
Author(s):  
S. Debnath ◽  
J. Kundu ◽  
B. Bhattacharyya
Keyword(s):  
Mathematical Modeling ◽  
Electrochemical Machining ◽  
Burr Formation ◽  
Duty Ratio ◽  
Minimum Width ◽  
Applied Frequency ◽  
Early Adoption ◽  
Novel Approach ◽  
Microfabrication Techniques

To adapt with today's rapidly changing world, fabrication of intricate microparts is becoming an urgent need. Manufacturing of these microparts with stringent requirements necessitates the early adoption of different microfabrication techniques. Wire electrochemical machining (WECM) is such a process which removes excess metal by dissolving it electrochemically. This process can easily generate features downscaled to micron ranges and offers several advantages like the requirement of very simple setup, fabrication of accurate complex microfeatures without undergoing any thermal stress, burr formation, and tool wear, which make it superior from other existing micromachining processes. However, this process is new, and little is known about its applicability and feasibility. Hence, the present work is directed towards developing suitable WECM setup to fabricate microfeatures by introducing proper means for enhancing the mass transport phenomenon. The tungsten tool wire for machining has been in situ etched to a diameter of 23.43 μm by a novel approach for retaining its regular cylindrical form and has been implemented during machining. Moreover, the influences of high duty ratio and applied frequency have been investigated on the corresponding width of the fabricated microslits and the experimental results have been represented graphically where the minimum width of the microslit is obtained as 44.85 μm. Furthermore, mathematical modeling has been developed to correlate duty ratio and applied frequency with generated slit width. Additionally, the mathematical modeling has been validated with practical results and complex stepped type microfeatures have been generated to establish process suitability.

scholarly journals STUDY OF FOOTWAY AND BIKE TRAVEL FACILITIES AS A PUBLIC TRANSPORT MODE INTEGRATION FACILITY IN SOUTH TANGERANG CITY (CASE STUDY: SUDIMARA STATION)

ASTONJADRO ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 71
Author(s):  
Muhammad Baharudin Sah
Keyword(s):  
Public Transportation ◽  
Population Growth Rate ◽  
Field Survey ◽  
Service Level ◽  
Microsoft Excel ◽  
Street Vendors ◽  
Minimum Width ◽  
Street Lighting ◽  
Transfer Of Function

It is known that South Tangerang City is one of the fastest growing cities. This indicates that the increasing number of users of transportation means that facilities for transportation users need to be considered, one example is pedestrians. The unrealized development of pedestrian facilities is caused by the transfer of function of pedestrian facilities for public needs and insufficient space for pedestrians. The lack of pedestrian facilities causes pedestrians to pass by and has an impact on public transportation that is currently operating, causing congestion. Sudimara Station is located in Ciputat District, South Tanggerang City, with a population growth rate of 3.0% in 2019. All buildings are provided for pedestrians to provide services to pedestrians so as to improve pedestrian smoothness, safety and comfort. The purpose of this study was to analyze the performance of pedestrian facilities at Sudimara Station. The method used is direct field survey and data processing using Microsoft Excel, AutoCad. The results of the author's research include the minimum width of the sidewalk in 2020 and 2025 of 1.5 - 1.6 meters and the service level of pedestrian facilities is classified as A, which means that pedestrians can walk freely, including being able to determine the direction of walking freely, at speed. relatively fast without causing interference between pedestrians. the existing conditions of the sidewalks in 2020, namely there are several obstacles for pedestrians such as the presence of street vendors, public transportation parking carelessly, and several motorbikes parked carelessly, buying and selling activities in markets close to Sudimara station and the absence of integration facilities around the place. the. Planning that the authors do is to increase the width of the sidewalk to 1.5 meters, and the addition of street lighting facilities.

scholarly journals ANALISIS DAN ARAHAN PENGEMBANGAN RUANG TERBUKA HIJAU DALAM MENDUKUNG GREEN CITY KOTA UNGARAN KABUPATEN SEMARANG

2016 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Antonius Dwi Yunianto, Santun R. P. Sitorus, dan Khursatul Munibah
Keyword(s):  
Open Space ◽  
Green Design ◽  
Wide Area ◽  
Analysis Method ◽  
Analytic Hierarchy ◽  
Minimum Width ◽  
The Public ◽  
Hierarchy Process ◽  
Mapping Result ◽  
Green City

The provision of Green Open Space (GOS) constitutes an important need for city and as a mandate ofthe Law on Spatial Planning. Ungaran city currently has the width of public GOS under 20%. It makesUngaran city has not yet qualified to become a Green City. The objectives of this study are to identify andanalyze the width and distribution of GOS existing condition; to analyze the needs of Ungaran’s GOSin order to meet the specified conditions of prevailing law; to arrange the plan of GOS based on GreenPlanning concept; and to arrange the design of GOS based on Green Design concept. The analysis willbe conducted by using Patch Analysis method. The analysis of GOS is based on the inhabitant’s needand the wide area, and the Analytic Hierarchy Process (AHP). The GOS mapping result of Ungarancity is 2.190,66 ha which consists of private GOS (2.112,74 ha) and public GOS (77,92 ha). Based onthe total projection of population in 2032, the public GOS need is 292,41 ha. Whereas the needs ofpublic GOS based on the 20% from wide area (612,17 ha). The direction of public GOS developmentbased on green planning is divided into three alternatives, first, based on the balance distribution ofGOS within the area, and land use priority; second, based on the balance distribution of GOS, land usepriority, distance to the residence, minimum width of 250m2, and the complexity of landform; third,based on the consideration of the spatial patterns and regional asset authority. The direction of publicGOS development is based on green design approach to divide the design based on necessity activityand function patterns of public GOS.

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