Performance Evaluation of Multimodal Transportation Systems

AbstractConnectivity of more than one mode to a line haul in an urban area constitutes the multimodal transport system of the city. In this paper New Delhi has been taken up as a case study to evaluate performance of multimodal transportation system (MMTS), where metro became main mode in routine public transport trips. Public transport in Delhi carries only about 60% of total vehicular person trips as against 80% of the expected population size of the city. The present bus services, metro rail and IRBT (Integrated Rail-cum-Bus Transit), if implemented as planned together are estimated to carry about 15 million trips per day by 2021. Since, all the public transport trips are multimodal, it is necessary to evaluate the performance of multimodal transportation systems. The study is divided into two phases. In the first phase, the study of travel time elements (access time, transfer time, waiting time, line-haul time, and egress time) is done. Next, the influence of access and egress times on the total travel time is examined. Use is made of a comprehensive commuter travel diary to collect detail travel time estimates. A representative commuter survey, with 460 respondents, is drawn on platform at each station of Red Line and Yellow Line (Kashmiri Gate – Saket) Delhi Metro. Implementing the Second phase of study, performance measures such as Travel Time Ratio, Level of Service, Interconnectivity Ratio, Passenger Waiting Index, and Running Index were evaluated. Interconnectivity ratio (proportion of access and egress time w.r.t total travel time) for various combinations such as Mixed-Metro-Mixed, Walk-Metro-Walk, Walk-Metro-Bus and Walk- Bus-Walk has been observed. Travel Time (defined as the time differential between private transport and public transport) ratio shows much variation with trip direction, time of day, mode used, and distance travelled, etc.,. Level of Service Indicator (Out- of-vehicle Travel Time/In-Vehicle Travel Time) ratio inferred that people spends more time out-of-vehicle as compared to that of in-vehicle. Access time, transfer time, waiting time and egress time are the most important and complex travel time elements that transport systems should consider improving its efficiency and modal share. The results can be used in planning catchment area of public transport. Access and egress (together with waiting and transfer times) appear as factors that affect effectiveness and performance of a multimodal transportation system to a larger extent as unacceptable distances are likely to reduce ridership patronage. At the same time, there are key deciding factors when a trip originates as to whether the commuter shall choose public transit over personal mode of travel

A Cross-Sectional Study on Knowledge about Swine Flu among First-Year MBBS Students in Mamata Medical College, Khammam

Introduction: An outbreak of the H1N1 swine flu virus, in march 2009, spread rapidly through the world, leading to the declaration of an influenza pandemic by WHO on 11th June 2009.Objective: To assess the knowledge about swine flu among first-year MBBS students.Materials and Methods: A cross-sectional study was conducted among first-year MBBS students of Mamata Medical College, Khammam, Telangana, during April 2015. Data were collected by using pilot-tested, self-administered questionnaire and results were analyzed by using SPSS version 19.Results: Majority 110 (96.5%) of the students are having correct knowledge regarding symptoms of swine flu. Around 58 (50.9%) students are having knowledge regarding spread/ mode of transmission of swine flu. Majority 74 (64.9%) of the students are having knowledge regarding availability of medication for swine flu.Conclusion: The awareness regarding H1N1 infection was adequate among the students who participated in this study and this can be attributed to the immediate training given to these students as well as to the mass media campaign which is important in epidemic situations to avoid its spread and complication

Characterization of the first hexacoordinate phosphorus compound with S→P←S bonds

The first example of a hexacoordinate phosphorus compound [S{6-t-Bu-4-Me-C6H2O}2]2P+(Cl-· C3H4N2) with two S→P bonds is reported. This compound can be construed as an oxophosphonium salt with double intramolecular coordination by sulfur atoms. X-ray structure reveals a facial arrangement of the ligands with two coordinating sulfur atoms cis to each other. The S→P distance of 2.334 (1) Å is one among very short coordinate bond distances between sulfur and phosphorus

Statistical properties of fracture in a random spring model

Using large scale numerical simulations we analyze the statistical properties of fracture in the two dimensional random spring model and compare it with its scalar counterpart: the random fuse model. We first consider the process of crack localization measuring the evolution of damage as the external load is raised. We find that, as in the fuse model, damage is initially uniform and localizes at peak load. Scaling laws for the damage density, fracture strength and avalanche distributions follow with slight variations the behavior observed in the random fuse model. We thus conclude that scalar models provide a faithful representation of the fracture properties of disordered systems.Comment: 12 pages, 17 figures, 1 gif figur

Experimental Investigations for Evaluation of Mechanical Properties of Aluminum Matrix Composites Reinforced with Copper Particles

In this study, aluminum alloy Al 6061-copper particulate metal matrix composites were prepared with three different volume fractions of reinforcement 75 μm (1%, 2% and 3%) using stir casting route. The particles distribution, mechanical and physical properties are observed using SEM and XRD. Analysis is discussed on microstructure study and hardness; compression and density are explained in sight of mechanical and physical properties. Finally, it was observed from the results that the hardness, density and compression strength were increased by increasing in wt% of reinforcement

An Efficient Block Circulant Preconditioner For Simulating Fracture Using Large Fuse Networks

{\it Critical slowing down} associated with the iterative solvers close to the critical point often hinders large-scale numerical simulation of fracture using discrete lattice networks. This paper presents a block circlant preconditioner for iterative solvers for the simulation of progressive fracture in disordered, quasi-brittle materials using large discrete lattice networks. The average computational cost of the present alorithm per iteration is $O(rs log s) + delops$, where the stiffness matrix ${\bf A}$ is partioned into $r$-by-$r$ blocks such that each block is an $s$-by-$s$ matrix, and $delops$ represents the operational count associated with solving a block-diagonal matrix with $r$-by-$r$ dense matrix blocks. This algorithm using the block circulant preconditioner is faster than the Fourier accelerated preconditioned conjugate gradient (PCG) algorithm, and alleviates the {\it critical slowing down} that is especially severe close to the critical point. Numerical results using random resistor networks substantiate the efficiency of the present algorithm.Comment: 16 pages including 2 figure

Influence of Al Content on the Corrosion Behavior of Biodegradable Magnesium Alloys in Simulated Physiological Solution

Magnesium (Mg) and its alloys have gained wide popularity in the biomedical field as promising candidates for degradable implant applications. Among Mg alloys, AZ (aluminum and zinc) series alloys are the most widely investigated for implant applications and reported in the literature. In all AZ series Mg alloys, aluminium content is the influencing factor that imparts different properties to the Mg alloys. In the present study, pure Mg, AZ31 and AZ91 Mg alloys were selected and the effect of aluminium content on the biocorrosion has been investigated in Ringer’s solution. It was a clear observation that the increased aluminum content has a severe effect on the degradation behavior of magnesium. From the weight loss measurements, AZ31 has shown lower corrosion rate compared with pure Mg and AZ91. The surface morphologies also showed the formation of more pits on pure Mg and AZ91 Mg alloy compared with AZ31 Mg alloy. By correlating the degradation behavior with the microstructure, galvanic corrosion was found to be the main reason behind the accelerated corrosion rate in AZ91 Mg alloy compared with AZ31 alloy. The phases on the corroded sample surfaces were examined by X-ray diffraction (XRD) method and scanning electron microscopy (SEM) and found that the corrosion products which were deposited on the surfaces provided protection against the chloride ions which was indicated by the decreased corrosion rates as immersion time was increased

Nanomechanical sensing using spins in diamond

Nanomechanical sensors and quantum nanosensors are two rapidly developing technologies that have diverse interdisciplinary applications in biological and chemical analysis and microscopy. For example, nanomechanical sensors based upon nanoelectromechanical systems (NEMS) have demonstrated chip-scale mass spectrometry capable of detecting single macromolecules, such as proteins. Quantum nanosensors based upon electron spins of negatively-charged nitrogen-vacancy (NV) centers in diamond have demonstrated diverse modes of nanometrology, including single molecule magnetic resonance spectroscopy. Here, we report the first step towards combining these two complementary technologies in the form of diamond nanomechanical structures containing NV centers. We establish the principles for nanomechanical sensing using such nano-spin-mechanical sensors (NSMS) and assess their potential for mass spectrometry and force microscopy. We predict that NSMS are able to provide unprecedented AC force images of cellular biomechanics and to, not only detect the mass of a single macromolecule, but also image its distribution. When combined with the other nanometrology modes of the NV center, NSMS potentially offer unparalleled analytical power at the nanoscale.Comment: Errors in the stress susceptibility parameters present in the original arXiv version have been correcte

New appraisal values of travel time saving and reliability in Great Britain

© 2017, The Author(s). This paper provides an overview of the study ‘Provision of market research for value of time savings and reliability’ undertaken by the Arup/ITS Leeds/Accent consortium for the UK Department for Transport (DfT). The paper summarises recommendations for revised national average values of in-vehicle travel time savings, reliability and time-related quality (e.g. crowding and congestion), which were developed using willingness-to-pay (WTP) methods, for a range of modes, and covering both business and non-work travel purposes. The paper examines variation in these values by characteristics of the traveller and trip, and offers insights into the uncertainties around the values, especially through the calculation of confidence intervals. With regards to non-work, our recommendations entail an increase of around 50% in values for commute, but a reduction of around 25% for other non-work—relative to previous DfT ‘WebTAG’ guidance. With regards to business, our recommendations are based on WTP, and thus represent a methodological shift away from the cost saving approach (CSA) traditionally used in WebTAG. These WTP-based business values show marked variation by distance; for trips of less than 20miles, values are around 75% lower than previous WebTAG values; for trips of around 100miles, WTP-based values are comparable to previous WebTAG; and for longer trips still, WTP-based values exceed those previously in WebTAG