Sample records for road load simulator

  1. On the road performance tests of electric test vehicle for correlation with road load simulator

    NASA Technical Reports Server (NTRS)

    Dustin, M. O.; Slavik, R. J.

    1982-01-01

    A dynamometer (road load simulator) is used to test and evaluate electric vehicle propulsion systems. To improve correlation between system tests on the road load simulator and on the road, similar performance tests are conducted using the same vehicle. The results of track tests on the electric propulsion system test vehicle are described. The tests include range at constant speeds and over SAE J227a driving cycles, maximum accelerations, maximum gradability, and tire rolling resistance determination. Road power requirements and energy consumption were also determined from coast down tests.

  2. 40 CFR 86.229-94 - Road load force, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Road load force, test weight, and... § 86.229-94 Road load force, test weight, and inertia weight class determination. (a) Flywheels, electrical forces, or other means of simulating test weight as shown in the table in this paragraph shall be...

  3. A laboratory facility for electric vehicle propulsion system testing

    NASA Technical Reports Server (NTRS)

    Sargent, N. B.

    1980-01-01

    The road load simulator facility located at the NASA Lewis Research Center enables a propulsion system or any of its components to be evaluated under a realistic vehicle inertia and road loads. The load is applied to the system under test according to the road load equation: F(net)=K1F1+K2F2V+K3 sq V+K4(dv/dt)+K5 sin theta. The coefficient of each term in the equation can be varied over a wide range with vehicle inertial representative of vehicles up to 7500 pounds simulated by means of flywheels. The required torque is applied by the flywheels, a hydroviscous absorber and clutch, and a drive motor integrated by a closed loop control system to produce a smooth, continuous load up to 150 horsepower.

  4. Preliminary results for model identification in characterizing 2-D topographic road profiles

    NASA Astrophysics Data System (ADS)

    Kern, Joshua V.; Ferris, John B.

    2006-05-01

    Load data representing severe customer usage is needed throughout a chassis development program; the majority of these chassis loads originate with the excitation from the road. These chassis loads are increasingly derived from vehicle simulations. Simulating a vehicle traversing long roads is simply impractical, however, and a greatly reduced set of characteristic roads must be found. In order to characterize a road, certain modeling assumptions must be made. Several models have been proposed making various assumptions about the properties that road profiles possess. The literature in this field is reviewed before focusing on two modeling assumptions of particular interest: the stationarity of the signal (homogeneity of the road) and the corresponding interval over which previous data points are correlated to the current data point. In this work, 2-D topographic road profiles are considered to be signals that are realizations of a stochastic process. The objective of this work is to investigate the stationarity assumption and the interval of influence for several carefully controlled sections of highway pavement in the United States. Two statistical techniques are used in analyzing these data: the autocorrelation and the partial autocorrelation. It is shown that the road profile signals in their original form are not stationary and have an extremely long interval of influence on the order of 25m. By differencing the data, however, it is often possible to generate stationary residuals and a very short interval of influence on the order of 250mm. By examining the autocorrelation and the partial autocorrelation, various versions of ARIMA models appear to be appropriate for further modeling. Implications to modeling the signals as Markov Chains are also discussed. In this way, roads can be characterized by the model architecture and the particular parameterization of the model. Any synthetic road realized from a particular model represents all profiles in this set. Realizations of any length can be generated, allowing efficient simulation and timely information about the chassis loads that can be used for design decisions. This work provides insights for future development in the modeling and characterization of 2-D topographic road profiles.

  5. Perceptual load in central and peripheral regions and its effects on driving performance: advertizing billboards.

    PubMed

    Marciano, Hadas; Yeshurun, Yaffa

    2012-01-01

    A broadened version of the perceptual load model was utilized to explore systematically the influence of four variables on driver's behavior: a. levels of load on the road; b. levels of load at the sides of the road; c. event's initial location (on the road vs. at the sides of the road); and d. the presence and size of advertizing billboards. 18 participants participated in two experimental sessions in a driving simulator. One of the sessions contained advertizing billboards and the other session did not. The results indicated that billboards can have a considerable effect on various aspects of driving like the time required responding to a potentially dangerous event or simply the number of accidents occurring during driving, but importantly the effect of billboards on driving was modulated by the levels of perceptual load.

  6. Assessment of the transportation route of oversize and excessive loads in relation to the load-bearing capacity of existing bridges

    NASA Astrophysics Data System (ADS)

    Doležel, Jiří; Novák, Drahomír; Petrů, Jan

    2017-09-01

    Transportation routes of oversize and excessive loads are currently planned in relation to ensure the transit of a vehicle through critical points on the road. Critical points are level-intersection of roads, bridges etc. This article presents a comprehensive procedure to determine a reliability and a load-bearing capacity level of the existing bridges on highways and roads using the advanced methods of reliability analysis based on simulation techniques of Monte Carlo type in combination with nonlinear finite element method analysis. The safety index is considered as a main criterion of the reliability level of the existing construction structures and the index is described in current structural design standards, e.g. ISO and Eurocode. An example of a single-span slab bridge made of precast prestressed concrete girders of the 60 year current time and its load bearing capacity is set for the ultimate limit state and serviceability limit state. The structure’s design load capacity was estimated by the full probability nonlinear MKP analysis using a simulation technique Latin Hypercube Sampling (LHS). Load-bearing capacity values based on a fully probabilistic analysis are compared with the load-bearing capacity levels which were estimated by deterministic methods of a critical section of the most loaded girders.

  7. Assessment of the transport routes of oversized and excessive loads in relation to the passage through roundabout

    NASA Astrophysics Data System (ADS)

    Petru, Jan; Dolezel, Jiri; Krivda, Vladislav

    2017-09-01

    In the past the excessive and oversized loads were realized on selected routes on roads that were adapted to ensure smooth passage of transport. Over the years, keeping the passages was abandoned and currently there are no earmarked routes which would be adapted for such type of transportation. The routes of excessive and oversized loads are currently planned to ensure passage of the vehicle through the critical points on the roads. Critical points are level and fly-over crossings of roads, bridges, toll gates, traffic signs and electrical and other lines. The article deals with the probability assessment of selected critical points of the route of the excessive load on the roads of 1st class, in relation to ensuring the passage through the roundabout. The bases for assessing the passage of the vehicle with excessive load through a roundabout are long-term results of video analyses of monitoring the movement of transports on similar intersections and determination of the theoretical probability model of vehicle movement at selected junctions. On the basis of a virtual simulation of the vehicle movement at crossroads and using MonteCarlo simulation method vehicles’ paths are analysed and the probability of exit of the vehicle outside the crossroad in given junctions is quantified.

  8. Shear test on viscoelastic granular material using Contact Dynamics simulations

    NASA Astrophysics Data System (ADS)

    Quezada, Juan Carlos; Sagnol, Loba; Chazallon, Cyrille

    2017-06-01

    By means of 3D contact dynamic simulations, the behavior of a viscoelastic granular material under shear loading is investigated. A viscoelastic fluid phase surrounding the solid particles is simulated by a contact model acting between them. This contact law was implemented in the LMGC90 software, based on the Burgers model. This model is able to simulate also the effect of creep relaxation. To validate the proposed contact model, several direct shear tests were performed, experimentally and numerically using the Leutner device. The numerical samples were created using spheres with two particle size distribution, each one identified for two layers from a road structure. Our results show a reasonable agreement between experimental and numerical data regarding the strain-stress evolution curves and the stress levels measured at failure. The proposed model can be used to simulate the mechanical behavior of multi-layer road structure and to study the influence of traffic on road deformation, cracking and particles pull-out induced by traffic loading.

  9. Comparison of road load simulator test results with track tests on electric vehicle propulsion system

    NASA Technical Reports Server (NTRS)

    Dustin, M. O.

    1983-01-01

    A special-purpose dynamometer, the road load simulator (RLS), is being used at NASA's Lewis Research Center to test and evaluate electric vehicle propulsion systems developed under DOE's Electric and Hybrid Vehicle Program. To improve correlation between system tests on the RLS and track tests, similar tests were conducted on the same propulsion system on the RLS and on a test track. These tests are compared in this report. Battery current to maintain a constant vehicle speed with a fixed throttle was used for the comparison. Scatter in the data was greater in the track test results. This is attributable to variations in tire rolling resistance and wind effects in the track data. It also appeared that the RLS road load, determined by coastdown tests on the track, was lower than that of the vehicle on the track. These differences may be due to differences in tire temperature.

  10. The Pneumatic Actuators As Vertical Dynamic Load Simulators On Medium Weighted Wheel Suspension Mechanism

    NASA Astrophysics Data System (ADS)

    Ka'ka, Simon; Himran, Syukri; Renreng, Ilyas; Sutresman, Onny

    2018-02-01

    Almost all of road damage can be caused by dynamic loads of vehicles that fluctuate according to the type of vehicle that passes through. This study aims to calculate the vertical dynamic load of the vehicle actually occurs on road construction by the mechanism of vehicle wheel suspension. Pneumatic cylinders driven by pressurized air directly load the spring and shock absorber installed on the wheels of the vehicle. The load fluctuations of the medium weight categorized vehicles are determined by the regulation of the amount of pressurized air that enters into the pneumatic cylinder chamber, pushing the piston and connecting rods. The displacement that occurs during compression on the spring and shock absorber, is substituted into the equation of vehicle dynamic load while taking into account the spring stiffness constant, and the fluid or damper gas coefficient. The results show that the magnitude of the displacement when the compression force works has significant influences to the amount of vertical dynamic load of the vehicle that overlies the road construction. The presence of dynamic load of vehicles that fluctuates and repeats, also affects on the reduction of road ability to receive the load. Experimental results using pneumatic actuators instead of real dynamic vehicle loads illustrate the characteristics of the relationship between work pressure and dynamic load. If the working pressure of P2 (bar) is greater, the vertical dynamic load Ft (N) that overloads the road structure is also greater. The associate graphs show that the shock absorber has a greater ability to reduce dynamic load vertically that burden the road structure when compared with the ability of screw spring.

  11. Grip Analysis of Road Surface and Tire Footprint Using FEM

    NASA Astrophysics Data System (ADS)

    Sabri, M.; Abda, S.

    2018-02-01

    Road grip involve a touch between road pavement and the tire tread pattern. The load bearing surface, which depends on pavement roughness and local pressures in the contact patch. This research conducted to develop a Finite element model for simulating the experimentally testing of asphalt in Jl. AH Nasution Medan, North Sumatera Indonesia base on the value of grip coefficient from various tire loads and the various speed of the vehicle during contact to the road. A tire model and road pavement are developed for the analyses the geometry of tire footprint. The results showed that the greater the mass of car will increase grip coefficient. The coefficient of grip on the road surface contact trough the tire footprint strongly influence the kinetic coefficient of friction at certain speeds. Experimentally show that Concrete road grip coefficient of more than 34% compared to the asphalt road at the same IRI parameters (6-8). Kinetic friction coefficient more than 0.33 was obtained in a asphalt path at a speed of 30-40 Km/hour.

  12. Design and Modeling of a Test Bench for Dual-Motor Electric Drive Tracked Vehicles Based on a Dynamic Load Emulation Method.

    PubMed

    Wang, Zhe; Lv, Haoliang; Zhou, Xiaojun; Chen, Zhaomeng; Yang, Yong

    2018-06-21

    Dual-motor Electric Drive Tracked Vehicles (DDTVs) have attracted increasing attention due to their high transmission efficiency and economical fuel consumption. A test bench for the development and validation of new DDTV technologies is necessary and urgent. How to load the vehicle on a DDTV test bench exactly the same as on a real road is a crucial issue when designing the bench. This paper proposes a novel dynamic load emulation method to address this problem. The method adopts dual dynamometers to simulate both the road load and the inertia load that are imposed on the dual independent drive systems. The vehicle’s total inertia equivalent to the drive wheels is calculated with separate consideration of vehicle body, tracks and road wheels to obtain a more accurate inertia load. A speed tracking control strategy with feedforward compensation is implemented to control the dual dynamometers, so as to make the real-time dynamic load emulation possible. Additionally, a MATLAB/Simulink model of the test bench is built based on a dynamics analysis of the platform. Experiments are finally carried out on this test bench under different test conditions. The outcomes show that the proposed load emulation method is effective, and has good robustness and adaptability to complex driving conditions. Besides, the accuracy of the established test bench model is also demonstrated by comparing the results obtained from the simulation model and experiments.

  13. Numerical investigation of road salt impact on an urban wellfield.

    PubMed

    Bester, M L; Frind, E O; Molson, J W; Rudolph, D L

    2006-01-01

    The impact of road salt on a wellfield in a complex glacial moraine aquifer system is studied by numerical simulation. The moraine underlies an extensive urban and industrial landscape, which draws its water supply from >20 wellfields, several of which are approaching or have exceeded the drinking water limit for chloride. The study investigates the mechanisms of road salt infiltration, storage, and transport in the subsurface and assesses the effectiveness of mitigation measures designed to reduce the impact. The three-dimensional transport model accounts for increases in salt loading, as well as growth of the urbanized area and road network over the past 50 years. The simulations, which focus on one impacted wellfield, show chloride plumes originating mainly at arterial roads and migrating through aquitard windows into the water supply aquifers. The results suggest that the aquifer system contains a large and heterogeneously distributed mass of chloride and that concentrations in the aquifer can be substantially higher than the concentrations in the well water. Future impact scenarios indicate that although the system responds rapidly to reductions in salt loading, the residual chloride mass may take decades to flush out, even if road salting were discontinued. The implications with respect to urban wellfields in typical snow-belt areas are discussed.

  14. Dynamic simulation of road vehicle door window regulator mechanism of cross arm type

    NASA Astrophysics Data System (ADS)

    Miklos, I. Zs; Miklos, C.; Alic, C.

    2017-01-01

    The paper presents issues related to the dynamic simulation of a motor-drive operating mechanism of cross arm type, for the manipulation of road vehicle door windows, using Autodesk Inventor Professional software. The dynamic simulation of the mechanism involves a 3D modelling, kinematic coupling, drive motion parameters and external loads, as well as the graphically view of the kinematic and kinetostatic results for the various elements and kinematic couplings of the mechanism, under real operating conditions. Also, based on the results, the analysis of the mechanism components has been carried out using the finite element method.

  15. Effect of Variation of Speed Limits on Intercity Bus Fuel Consumption, Coach and Driver Utilization, and Corporate Profitability

    DOT National Transportation Integrated Search

    1975-11-01

    The effect of speed limit and passenger load on fuel consumption was determined using actual intercity buses with simulated passenger loads over different types of terrain. In addition to road tests, laboratory type measurements were made on four int...

  16. Transient Response of a PEM Fuel Cell Representing Variable Load for a Moving Vehicle on Urban Roads

    DOT National Transportation Integrated Search

    2001-01-01

    Three-dimensional numerical simulation of transient response of a Polymer Electrolyte Membrane (PEM) fuel cell subjected to a variable load is developed. The model parameters are typical of experimental cell for a 10-cm2 reactive area with serpentine...

  17. Estimation of road profile variability from measured vehicle responses

    NASA Astrophysics Data System (ADS)

    Fauriat, W.; Mattrand, C.; Gayton, N.; Beakou, A.; Cembrzynski, T.

    2016-05-01

    When assessing the statistical variability of fatigue loads acting throughout the life of a vehicle, the question of the variability of road roughness naturally arises, as both quantities are strongly related. For car manufacturers, gathering information on the environment in which vehicles evolve is a long and costly but necessary process to adapt their products to durability requirements. In the present paper, a data processing algorithm is proposed in order to estimate the road profiles covered by a given vehicle, from the dynamic responses measured on this vehicle. The algorithm based on Kalman filtering theory aims at solving a so-called inverse problem, in a stochastic framework. It is validated using experimental data obtained from simulations and real measurements. The proposed method is subsequently applied to extract valuable statistical information on road roughness from an existing load characterisation campaign carried out by Renault within one of its markets.

  18. Aerodynamic Drag Reduction Technologies Testing of Heavy-Duty Vocational Vehicles and a Dry Van Trailer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ragatz, Adam; Thornton, Matthew

    This study focused on two accepted methods for quantifying the benefit of aerodynamic improvement technologies on vocational vehicles: the coastdown technique, and on-road constant speed fuel economy measurements. Both techniques have their advantages. Coastdown tests are conducted over a wide range in speed and allow the rolling resistance and aerodynamic components of road load force to be separated. This in turn allows for the change in road load and fuel economy to be estimated at any speed, as well as over transient cycles. The on-road fuel economy measurements only supply one lumped result, applicable at the specific test speed, butmore » are a direct measurement of fuel usage and are therefore used in this study as a check on the observed coastdown results. Resulting coefficients were then used to populate a vehicle model and simulate expected annual fuel savings over real-world vocational drive cycles.« less

  19. Estimating total maximum daily loads with the Stochastic Empirical Loading and Dilution Model

    USGS Publications Warehouse

    Granato, Gregory; Jones, Susan Cheung

    2017-01-01

    The Massachusetts Department of Transportation (DOT) and the Rhode Island DOT are assessing and addressing roadway contributions to total maximum daily loads (TMDLs). Example analyses for total nitrogen, total phosphorus, suspended sediment, and total zinc in highway runoff were done by the U.S. Geological Survey in cooperation with FHWA to simulate long-term annual loads for TMDL analyses with the stochastic empirical loading and dilution model known as SELDM. Concentration statistics from 19 highway runoff monitoring sites in Massachusetts were used with precipitation statistics from 11 long-term monitoring sites to simulate long-term pavement yields (loads per unit area). Highway sites were stratified by traffic volume or surrounding land use to calculate concentration statistics for rural roads, low-volume highways, high-volume highways, and ultraurban highways. The median of the event mean concentration statistics in each traffic volume category was used to simulate annual yields from pavement for a 29- or 30-year period. Long-term average yields for total nitrogen, phosphorus, and zinc from rural roads are lower than yields from the other categories, but yields of sediment are higher than for the low-volume highways. The average yields of the selected water quality constituents from high-volume highways are 1.35 to 2.52 times the associated yields from low-volume highways. The average yields of the selected constituents from ultraurban highways are 1.52 to 3.46 times the associated yields from high-volume highways. Example simulations indicate that both concentration reduction and flow reduction by structural best management practices are crucial for reducing runoff yields.

  20. Estimation of Road Friction Coefficient in Different Road Conditions Based on Vehicle Braking Dynamics

    NASA Astrophysics Data System (ADS)

    Zhao, You-Qun; Li, Hai-Qing; Lin, Fen; Wang, Jian; Ji, Xue-Wu

    2017-07-01

    The accurate estimation of road friction coefficient in the active safety control system has become increasingly prominent. Most previous studies on road friction estimation have only used vehicle longitudinal or lateral dynamics and often ignored the load transfer, which tends to cause inaccurate of the actual road friction coefficient. A novel method considering load transfer of front and rear axles is proposed to estimate road friction coefficient based on braking dynamic model of two-wheeled vehicle. Sliding mode control technique is used to build the ideal braking torque controller, which control target is to control the actual wheel slip ratio of front and rear wheels tracking the ideal wheel slip ratio. In order to eliminate the chattering problem of the sliding mode controller, integral switching surface is used to design the sliding mode surface. A second order linear extended state observer is designed to observe road friction coefficient based on wheel speed and braking torque of front and rear wheels. The proposed road friction coefficient estimation schemes are evaluated by simulation in ADAMS/Car. The results show that the estimated values can well agree with the actual values in different road conditions. The observer can estimate road friction coefficient exactly in real-time and resist external disturbance. The proposed research provides a novel method to estimate road friction coefficient with strong robustness and more accurate.

  1. Structural strength assessment of the reconstructed road structure in terms of the loading time and yield criterion

    NASA Astrophysics Data System (ADS)

    Mazurek, Grzegorz; Iwański, Marek

    2018-05-01

    This article reports the results of numerical simulations of the stress-strain states in the rebuilt road structure compared to the solutions contained in the Polish Catalogue, with the true characteristics of the layer materials taken into account. In the case analysed, a cold-recycled base layer with foamed bitumen as a recycling agent was used. The presented analysis is complementary to the mandatory in Poland procedure of mechanistic pavement design based on a linear elastic model. The temperature distribution in the road structure was analysed at the reference temperature of 40°C on the asphalt layer surface. The loading time was included in the computer simulations through the use of the classic generalized Maxwell model and thus the stiffness-time history of the layers had to be determined. For this purpose, the dynamic modulus E* tests of the loading time frequency from 0.1 Hz to 20 Hz were carried out, and the yield point was modelled using the Coulomb-Mohr failure criterion calculated on the basis of triaxial compression tests. The analytical solution to the problem was found with ABAQUS. The results demonstrate that the high temperature of asphalt layers and long loading time noticeably reduces the stiffness modulus in those layers. That reduction changes the principal stress levels, which significantly influences the shear stress both in the recycled base layer and in the subgrade soil. Should the yield point be exceeded rapidly in the recycled layer, the horizontal stresses in the asphalt layers will increase and adversely affect the durability of the reconstructed road pavement structure, especially in the zones of slow heavy vehicle traffic.

  2. Steady-state and dynamic evaluation of the electric propulsion system test bed vehicle on a road load simulator

    NASA Technical Reports Server (NTRS)

    Dustin, M. O.

    1983-01-01

    The propulsion system of the Lewis Research Center's electric propulsion system test bed vehicle was tested on the road load simulator under the DOE Electric and Hybrid Vehicle Program. This propulsion system, consisting of a series-wound dc motor controlled by an infinitely variable SCR chopper and an 84-V battery pack, is typical of those used in electric vehicles made in 1976. Steady-state tests were conducted over a wide range of differential output torques and vehicle speeds. Efficiencies of all of the components were determined. Effects of temperature and voltage variations on the motor and the effect of voltage changes on the controller were examined. Energy consumption and energy efficiency for the system were determined over the B and C driving schedules of the SAE J227a test procedure.

  3. Aerodynamic loads on buses due to crosswind gusts: extended analysis

    NASA Astrophysics Data System (ADS)

    Drugge, Lars; Juhlin, Magnus

    2010-12-01

    The objective of this work is to use inverse simulations on measured vehicle data in order to estimate the aerodynamic loads on a bus when exposed to crosswind situations. Tyre forces, driver input, wind velocity and vehicle response were measured on a typical coach when subjected to natural crosswind gusts. Based on these measurements and a detailed MBS vehicle model, the aerodynamic loads were estimated through inverse simulations. In order to estimate the lift force, roll and pitch moments in addition to the lateral force and yaw moment, the simulation model was extended by also incorporating the estimation of the vertical road disturbances. The proposed method enables the estimation of aerodynamic loads due to crosswind gusts without using a full scale wind tunnel adapted for crosswind excitation.

  4. Recent research and applications of numerical simulation for dynamic response of long-span bridges subjected to multiple loads.

    PubMed

    Chen, Zhiwei; Chen, Bo

    2014-01-01

    Many long-span bridges have been built throughout the world in recent years but they are often subject to multiple types of dynamic loads, especially those located in wind-prone regions and carrying both trains and road vehicles. To ensure the safety and functionality of these bridges, dynamic responses of long-span bridges are often required for bridge assessment. Given that there are several limitations for the assessment based on field measurement of dynamic responses, a promising approach is based on numerical simulation technologies. This paper provides a detailed review of key issues involved in dynamic response analysis of long-span multiload bridges based on numerical simulation technologies, including dynamic interactions between running trains and bridge, between running road vehicles and bridge, and between wind and bridge, and in the wind-vehicle-bridge coupled system. Then a comprehensive review is conducted for engineering applications of newly developed numerical simulation technologies to safety assessment of long-span bridges, such as assessment of fatigue damage and assessment under extreme events. Finally, the existing problems and promising research efforts for the numerical simulation technologies and their applications to assessment of long-span multiload bridges are explored.

  5. Recent Research and Applications of Numerical Simulation for Dynamic Response of Long-Span Bridges Subjected to Multiple Loads

    PubMed Central

    Chen, Zhiwei; Chen, Bo

    2014-01-01

    Many long-span bridges have been built throughout the world in recent years but they are often subject to multiple types of dynamic loads, especially those located in wind-prone regions and carrying both trains and road vehicles. To ensure the safety and functionality of these bridges, dynamic responses of long-span bridges are often required for bridge assessment. Given that there are several limitations for the assessment based on field measurement of dynamic responses, a promising approach is based on numerical simulation technologies. This paper provides a detailed review of key issues involved in dynamic response analysis of long-span multiload bridges based on numerical simulation technologies, including dynamic interactions between running trains and bridge, between running road vehicles and bridge, and between wind and bridge, and in the wind-vehicle-bridge coupled system. Then a comprehensive review is conducted for engineering applications of newly developed numerical simulation technologies to safety assessment of long-span bridges, such as assessment of fatigue damage and assessment under extreme events. Finally, the existing problems and promising research efforts for the numerical simulation technologies and their applications to assessment of long-span multiload bridges are explored. PMID:25006597

  6. Off-road motorbike performance analysis using a rear semi-active suspension

    NASA Astrophysics Data System (ADS)

    Lozoya-Santos, Jorge de J.; Cervantes-Muñoz, Damián.; Ramírez Mendoza, Ricardo

    2015-04-01

    The topic of this paper is the analysis of a control system for a semi active rear suspension in an off-road 2-wheel vehicle. Several control methods are studied, as well as the recently proposed Frequency Estimation Based (FEB) algorithm. The test motorcycle dynamics, as well as the passive, semi active, and the algorithm controlled shock absorber models are loaded into BikeSim, a professional two-wheeled vehicle simulation software, and tested in several road conditions. The results show a detailed comparison of the theoretical performance of the different control approaches in a novel environment for semi active dampers.

  7. Influence of tyre-road contact model on vehicle vibration response

    NASA Astrophysics Data System (ADS)

    Múčka, Peter; Gagnon, Louis

    2015-09-01

    The influence of the tyre-road contact model on the simulated vertical vibration response was analysed. Three contact models were compared: tyre-road point contact model, moving averaged profile and tyre-enveloping model. In total, 1600 real asphalt concrete and Portland cement concrete longitudinal road profiles were processed. The linear planar model of automobile with 12 degrees of freedom (DOF) was used. Five vibration responses as the measures of ride comfort, ride safety and dynamic load of cargo were investigated. The results were calculated as a function of vibration response, vehicle velocity, road quality and road surface type. The marked differences in the dynamic tyre forces and the negligible differences in the ride comfort quantities were observed among the tyre-road contact models. The seat acceleration response for three contact models and 331 DOF multibody model of the truck semi-trailer was compared with the measured response for a known profile of test section.

  8. Dynamic Analysis of an Office Building due to Vibration from Road Construction Activities

    NASA Astrophysics Data System (ADS)

    Chik, T. N. T.; Kamil, M. R. H.; Yusoff, N. A.; Ibrahim, M. H. W.

    2018-04-01

    Construction activities are widely known as one of the predominant sources of man-made vibrations that able to create nuisance towards any adjacent building, and this includes the road construction operations. Few studies conclude the construction-induced vibration may be harmful directly and indirectly towards the neighbouring building. This lead to the awareness of study the building vibration response of concrete masonry load bearing system and its vibrational performance towards the road construction activities. This study will simulate multi-storey office building of Sekolah Menengah Kebangsaan (SMK) Bandar Enstek at Negeri Sembilan by using finite element vibration analyses. The excitation of transient loads from ground borne vibrations which triggered by the road construction activities are modelled into the building. The vibration response was recorded during in-situ ambient vibration test by using Laser Doppler Vibrometer (LDV), which specifically performed on four different locations. The finite element simulation process was developed in the commercial FEA software ABAQUS. Then, the experimental data was processed and evaluated in MATLAB ModalV to assess the vibration criteria of the floor in building. As a result, the vibration level of floor in building is fall under VC-E curve which was under the maximum permissible level for office building (VC-ISO). The vibration level on floor is acceptable within the limit that have been referred.

  9. Analysis of Contraction Joint Width Influence on Load Stress of Pavement Panels

    NASA Astrophysics Data System (ADS)

    Gao, Wei; Cui, Wei; Sun, Wei

    2018-05-01

    The width of transverse contraction joint of the cement road varies with temperatures, which leads to changes in load transmission among plates of the road surface and affects load stress of the road plates. Three-dimensional element analysis software EverFE is used to address the relation between the contraction joint width and road surface load stress, revealing the impact of reducing contraction joint width. The results could be of critical value in maintaining road functions and extending the service life of cement road surfaces.

  10. Simulated effects of existing and proposed surface-water impoundments and gas-well pads on streamflow and suspended sediment in the Cypress Creek watershed, Arkansas

    USGS Publications Warehouse

    Hart, Rheannon M.

    2014-01-01

    The Arkansas Natural Resources Commission and the Arkansas Department of Environmental Quality list suspended sediment from “poor pastures” as a primary source of nonpoint-source pollution in north-central Arkansas, but unpaved (gravel) roads are another important source of suspended sediment. Because of the high sediment-loading rates associated with gravel roads and the large amount of pasture within the watershed, the factors most responsible for suspended sediment within the Cypress Creek watershed are likely associated more with the pastureland and gravel roads, than factors associated with gas-well pads/pipelines.

  11. [Characteristics of fugitive dust emission from paved road near construction activities].

    PubMed

    Tian, Gang; Fan, Shou-Bin; Li, Gang; Qin, Jian-Ping

    2007-11-01

    Because of the mud/dirt carryout from construction activities, the silt loading of paved road nearby is higher and the fugitive dust emission is stronger. By sampling and laboratory analysis of the road surface dust samples, we obtain the silt loading (mass of material equal to or less than 75 micromaters in physical diameter per unit area of travel surface) of paved roads near construction activities. The result show that silt loading of road near construction activities is higher than "normal road", and silt loading is negatively correlated with length from construction's door. According to AP-42 emission factor model of fugitive dust from roads, the emission factor of influenced road is 2 - 10 times bigger than "normal road", and the amount of fugitive dust emission influenced by one construction activity is "equivalent" to an additional road length of approximately 422 - 3 800 m with the baseline silt loading. Based on the spatial and temporal distribution of construction activities, in 2002 the amount of PM10 emission influenced by construction activities in Beijing city areas account of for 59% of fugitive dust from roads.

  12. A comparative study of noise pollution levels in some selected areas in Ilorin Metropolis, Nigeria.

    PubMed

    Oyedepo, Olayinka S; Saadu, Abdullahi A

    2009-11-01

    The noise pollution is a major problem for the quality of life in urban areas. This study was conducted to compare the noise pollution levels at busy roads/road junctions, passengers loading parks, commercial, industrial and residential areas in Ilorin metropolis. A total number of 47-locations were selected within the metropolis. Statistical analysis shows significant difference (P < 0.05) in noise pollution levels between industrial areas and low density residential areas, industrial areas and high density areas, industrial areas and passengers loading parks, industrial areas and commercial areas, busy roads/road junctions and low density areas, passengers loading parks and commercial areas and commercial areas and low density areas. There is no significant difference (P > 0.05) in noise pollution levels between industrial areas and busy roads/road junctions, busy roads/road junctions and high density areas, busy roads/road junctions and passengers loading parks, busy roads/road junctions and commercial areas, passengers loading parks and high density areas, passengers loading parks and commercial areas and commercial areas and high density areas. The results show that Industrial areas have the highest noise pollution levels (110.2 dB(A)) followed by busy roads/Road junctions (91.5 dB(A)), Passengers loading parks (87.8 dB(A)) and Commercial areas (84.4 dB(A)). The noise pollution levels in Ilorin metropolis exceeded the recommended level by WHO at 34 of 47 measuring points. It can be concluded that the city is environmentally noise polluted and road traffic and industrial machineries are the major sources of it. Noting the noise emission standards, technical control measures, planning and promoting the citizens awareness about the high noise risk may help to relieve the noise problem in the metropolis.

  13. 40 CFR 1066.210 - Dynamometers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... to recreate the mechanical inertia and frictional forces that a vehicle exerts on road surfaces... drive axles may share a single drive roll. Use good engineering judgment to ensure that the dynamometer... engineering judgment. (3) The load applied by the dynamometer simulates forces acting on the vehicle during...

  14. A NARX damper model for virtual tuning of automotive suspension systems with high-frequency loading

    NASA Astrophysics Data System (ADS)

    Alghafir, M. N.; Dunne, J. F.

    2012-02-01

    A computationally efficient NARX-type neural network model is developed to characterise highly nonlinear frequency-dependent thermally sensitive hydraulic dampers for use in the virtual tuning of passive suspension systems with high-frequency loading. Three input variables are chosen to account for high-frequency kinematics and temperature variations arising from continuous vehicle operation over non-smooth surfaces such as stone-covered streets, rough or off-road conditions. Two additional input variables are chosen to represent tuneable valve parameters. To assist in the development of the NARX model, a highly accurate but computationally excessive physical damper model [originally proposed by S. Duym and K. Reybrouck, Physical characterization of non-linear shock absorber dynamics, Eur. J. Mech. Eng. M 43(4) (1998), pp. 181-188] is extended to allow for high-frequency input kinematics. Experimental verification of this extended version uses measured damper data obtained from an industrial damper test machine under near-isothermal conditions for fixed valve settings, with input kinematics corresponding to harmonic and random road profiles. The extended model is then used only for simulating data for training and testing the NARX model with specified temperature profiles and different valve parameters, both in isolation and within quarter-car vehicle simulations. A heat generation and dissipation model is also developed and experimentally verified for use within the simulations. Virtual tuning using the quarter-car simulation model then exploits the NARX damper to achieve a compromise between ride and handling under transient thermal conditions with harmonic and random road profiles. For quarter-car simulations, the paper shows that a single tuneable NARX damper makes virtual tuning computationally very attractive.

  15. Thermo-Mechanical Analyses of Dynamically Loaded Rubber Cylinders

    NASA Technical Reports Server (NTRS)

    Johnson, Arthur R.; Chen, Tzi-Kang

    2002-01-01

    Thick rubber components are employed by the Army to carry large loads. In tanks, rubber covers road wheels and track systems to protect roadways. It is difficult for design engineers to simulate the details of the hysteretic heating for large strain viscoelastic deformations. In this study, an approximation to the viscoelastic energy dissipated per unit time is investigated for use in estimating mechanically induced viscoelastic heating. Coupled thermo-mechanical simulations of large cyclic deformations of rubber cylinders are presented. The cylinders are first compressed axially and then cyclically loaded about the compressed state. Details of the algorithm and some computational issues are discussed. The coupled analyses are conducted for tall and short rubber cylinders both with and without imbedded metal disks.

  16. Role of urban surface roughness in road-deposited sediment build-up and wash-off

    NASA Astrophysics Data System (ADS)

    Zhao, Hongtao; Jiang, Qian; Xie, Wenxia; Li, Xuyong; Yin, Chengqing

    2018-05-01

    Urban road surface roughness is one of the most important factors in estimation of surface runoff loads caused by road-deposited sediment (RDS) wash-off and design of its control measures. However, because of a lack of experimental data to distinguish the role of surface roughness, the effects of surface roughness on RDS accumulation and release are not clear. In this study, paired asphalt and concrete road surfaces and rainfall simulation designs were used to distinguish the role of surface roughness in RDS build-up and wash-off. Our results showed that typical asphalt surfaces often have higher depression depths than typical concrete surfaces, indicating that asphalt surfaces are relatively rougher than concrete surface. Asphalt surfaces can retain a larger RDS amount, relative higher percentage of coarser particles, larger RDS wash-off loads, and lower wash-off percentage, than concrete surfaces. Surface roughness has different effects in RDS motilities with different particle sizes during rainfall runoff, and the settleable particles (44-149 μm) were notably influenced by it. Furthermore, the first flush phenomenon tended to be greater on relatively smooth surfaces than relatively rough surfaces. Overall, surface roughness plays an important role in influencing the complete process of RDS build-up and wash-off on different road characteristics.

  17. Road load simulator tests of the Gould phase 1 functional model silicon controlled rectifier ac motor controller for electric vehicles

    NASA Astrophysics Data System (ADS)

    Gourash, F.

    1984-02-01

    The test results for a functional model ac motor controller for electric vehicles and a three-phase induction motor which were dynamically tested on the Lewis Research Center road load simulator are presented. Results show that the controller has the capability to meet the SAE-J227a D cycle test schedule and to accelerate a 1576-kg (3456-lb) simulated vehicle to a cruise speed of 88.5 km/hr (55 mph). Combined motor controller efficiency is 72 percent and the power inverter efficiency alone is 89 percent for the cruise region of the D cycle. Steady state test results for motoring, regeneration, and thermal data obtained by operating the simulator as a conventional dynamometer are in agreement with the contractor's previously reported data. The regeneration test results indicate that a reduction in energy requirements for urban driving cycles is attainable with regenerative braking. Test results and data in this report serve as a data base for further development of ac motor controllers and propulsion systems for electric vehicles. The controller uses state-of-the-art silicon controlled rectifier (SCR) power semiconductors and microprocessor-based logic and control circuitry. The controller was developed by Gould Laboratories under a Lewis contract for the Department of Energy's Electric and Hybrid Vehicle program.

  18. Road load simulator tests of the Gould phase 1 functional model silicon controlled rectifier ac motor controller for electric vehicles

    NASA Technical Reports Server (NTRS)

    Gourash, F.

    1984-01-01

    The test results for a functional model ac motor controller for electric vehicles and a three-phase induction motor which were dynamically tested on the Lewis Research Center road load simulator are presented. Results show that the controller has the capability to meet the SAE-J227a D cycle test schedule and to accelerate a 1576-kg (3456-lb) simulated vehicle to a cruise speed of 88.5 km/hr (55 mph). Combined motor controller efficiency is 72 percent and the power inverter efficiency alone is 89 percent for the cruise region of the D cycle. Steady state test results for motoring, regeneration, and thermal data obtained by operating the simulator as a conventional dynamometer are in agreement with the contractor's previously reported data. The regeneration test results indicate that a reduction in energy requirements for urban driving cycles is attainable with regenerative braking. Test results and data in this report serve as a data base for further development of ac motor controllers and propulsion systems for electric vehicles. The controller uses state-of-the-art silicon controlled rectifier (SCR) power semiconductors and microprocessor-based logic and control circuitry. The controller was developed by Gould Laboratories under a Lewis contract for the Department of Energy's Electric and Hybrid Vehicle program.

  19. Carbonaceous Aerosols Emitted from Light-Duty Vehicles Operating on Gasoline and Ethanol Fuel Blends

    EPA Science Inventory

    This study examines the chemical properties of carbonaceous aerosols emitted from three light-duty gasoline vehicles (LDVs) operating on gasoline (e0) and ethanol-gasoline fuel blends (e10 and e85). Vehicle road load simulations were performed on a chassis dynamometer using the t...

  20. CHARACTERIZATION OF HEAVY-DUTY MOTOR VEHICLE EMISSIONS UNDER TRANSIENT DRIVING CONDITIONS

    EPA Science Inventory

    The objective of this program was to characterize heavy-duty diesel truck and bus emissions produced during transient driving cycles. In the initial phase of the program an improved road-load simulation method was developed for use in operating large trucks on a chassis dynamomet...

  1. Preliminary results of steady state characterization of near term electric vehicle breadboard propulsion system

    NASA Technical Reports Server (NTRS)

    Sargent, N. B.

    1980-01-01

    The steady state test results on a breadboard version of the General Electric Near Term Electric Vehicle (ETV-1) are discussed. The breadboard was built using exact duplicate vehicle propulsion system components with few exceptions. Full instrumentation was provided to measure individual component efficiencies. Tests were conducted on a 50 hp dynamometer in a road load simulator facility. Characterization of the propulsion system over the lower half of the speed-torque operating range has shown the system efficiency to be composed of a predominant motor loss plus a speed dependent transaxle loss. At the lower speeds with normal road loads the armature chopper loss is also a significant factor. At the conditions corresponding to a cycle for which the vehicle system was specifically designed, the efficiencies are near optimum.

  2. Study on Stationarity of Random Load Spectrum Based on the Special Road

    NASA Astrophysics Data System (ADS)

    Yan, Huawen; Zhang, Weigong; Wang, Dong

    2017-09-01

    In the special road quality assessment method, there is a method using a wheel force sensor, the essence of this method is collecting the load spectrum of the car to reflect the quality of road. According to the definition of stochastic process, it is easy to find that the load spectrum is a stochastic process. However, the analysis method and application range of different random processes are very different, especially in engineering practice, which will directly affect the design and development of the experiment. Therefore, determining the type of a random process has important practical significance. Based on the analysis of the digital characteristics of road load spectrum, this paper determines that the road load spectrum in this experiment belongs to a stationary stochastic process, paving the way for the follow-up modeling and feature extraction of the special road.

  3. Perceptual load in different regions of the visual scene and its relevance for driving.

    PubMed

    Marciano, Hadas; Yeshurun, Yaffa

    2015-06-01

    The aim of this study was to better understand the role played by perceptual load, at both central and peripheral regions of the visual scene, in driving safety. Attention is a crucial factor in driving safety, and previous laboratory studies suggest that perceptual load is an important factor determining the efficiency of attentional selectivity. Yet, the effects of perceptual load on driving were never studied systematically. Using a driving simulator, we orthogonally manipulated the load levels at the road (central load) and its sides (peripheral load), while occasionally introducing critical events at one of these regions. Perceptual load affected driving performance at both regions of the visual scene. Critically, the effect was different for central versus peripheral load: Whereas load levels on the road mainly affected driving speed, load levels on its sides mainly affected the ability to detect critical events initiating from the roadsides. Moreover, higher levels of peripheral load impaired performance but mainly with low levels of central load, replicating findings with simple letter stimuli. Perceptual load has a considerable effect on driving, but the nature of this effect depends on the region of the visual scene at which the load is introduced. Given the observed importance of perceptual load, authors of future studies of driving safety should take it into account. Specifically, these findings suggest that our understanding of factors that may be relevant for driving safety would benefit from studying these factors under different levels of load at different regions of the visual scene. © 2014, Human Factors and Ergonomics Society.

  4. 40 CFR 1066.805 - Road-load power, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... (a) Simulate a vehicle's test weight on the dynamometer using the appropriate equivalent test weight shown in Table 1 of this section. Equivalent test weights are established according to each vehicle's... weight class corresponding to each equivalent test weight; the inertia weight class allows for grouping...

  5. Tests of an alternating current propulsion subsystem for electric vehicles on a road load simulator

    NASA Astrophysics Data System (ADS)

    Stenger, F. J.

    1982-12-01

    The test results of a breadboard version of an ac electric-vehicle propulsion subsystem are presented. The breadboard was installed in the NASA Lewis Research Center Road Load Simulator facility and tested under steady-state and transient conditions. Steady-state tests were run to characterize the system and component efficiencies over the complete speed-torque range within the capability of the propulsion subsystem in the motoring mode of operation. Transient tests were performed to determine the energy consumption of the breadboard over the acceleration and cruise portions of SAE J227 and driving schedules B, C, and D. Tests in the regenerative mode were limited to the low-gear-speed range of the two speed transaxle used in the subsystem. The maximum steady-state subsystem efficiency observed for the breadboard was 81.5 percent in the high-gear-speed range in the motoring mode, and 76 percent in the regenerative braking mode (low gear). The subsystem energy efficiency during the transient tests ranged from 49.2 percent for schedule B to 68.4 percent for Schedule D.

  6. Tests of an alternating current propulsion subsystem for electric vehicles on a road load simulator

    NASA Technical Reports Server (NTRS)

    Stenger, F. J.

    1982-01-01

    The test results of a breadboard version of an ac electric-vehicle propulsion subsystem are presented. The breadboard was installed in the NASA Lewis Research Center Road Load Simulator facility and tested under steady-state and transient conditions. Steady-state tests were run to characterize the system and component efficiencies over the complete speed-torque range within the capability of the propulsion subsystem in the motoring mode of operation. Transient tests were performed to determine the energy consumption of the breadboard over the acceleration and cruise portions of SAE J227 and driving schedules B, C, and D. Tests in the regenerative mode were limited to the low-gear-speed range of the two speed transaxle used in the subsystem. The maximum steady-state subsystem efficiency observed for the breadboard was 81.5 percent in the high-gear-speed range in the motoring mode, and 76 percent in the regenerative braking mode (low gear). The subsystem energy efficiency during the transient tests ranged from 49.2 percent for schedule B to 68.4 percent for Schedule D.

  7. A Study on the Rheological Properties of Recycled Rubber-Modified Asphalt Mixtures

    PubMed Central

    Karacasu, Murat; Er, Arzu

    2015-01-01

    Using waste rubber in asphalt mixes has become a common practice in road construction. This paper presents the results of a study on the rheological characteristics of rubber-modified asphalt (RMA) concrete under static and dynamic loading conditions. A number of static and dynamic creep tests were conducted on RMA mix specimens with different rubber sizes and contents, and a series of resonant column tests were conducted to evaluate the shear modulus and damping values. To simulate the stress-strain response of traffic-induced loading, the measurements were taken for different confining pressures and strain levels. The results of the study indicated that rubber modification increases stiffness and damping ratio, making it a very attractive material for use in road construction. However the grain size of the rubber is very important. Although RMA may cost up to 100% more than regular asphalt, the advantages it brings, such as an increased service life of the road and proper waste utilization contributing to a more sustainable infrastructure, may justify the added cost. PMID:25695096

  8. Test plan for performance testing of the Eaton AC-3 electric vehicle

    NASA Astrophysics Data System (ADS)

    Crumley, R.; Heiselmann, H. W.

    1985-04-01

    An alternating current (ac) propulsion system for an electric vehicle was developed and tested. The test bed vehicle is a modified 1981 Mercury Lynx. The test plan was prepared specifically for the third modification to this test bed and identified as the Eaton AC-3. The scope of the testing done on the Eaton AC-3 includes coastdown and dynamometer tests but does not include environmental, on-road, or track testing. Coastdown testing is performed in accordance with SAE J-1263 (SAE Recommended Practice for Road Load Measurement and Dynamometer Simulation Using Coastdown Techniques).

  9. NOx dispersion modelling around roundabout in a small city, example from Hungary

    NASA Astrophysics Data System (ADS)

    Farkas, Orsolya; Rákai, Anikó; Czáder, Károly; Török, Ákos

    2013-04-01

    The present paper focuses on the modelling of pollutant distribution and dispersion in an urban region that is located in a moderately industrialized town of Hungary, Székesfehérvár, with a population of 100,000. The study area is located close to the city centre, with different housing styles and different building elevations. High-rise buildings with 10 floors to small houses with gardens are found in the modelled area. The roundabout has 5 access roads; three major ones and two minor ones with different geometries and traffic load. The traffic load of the roads was defined by traffic count, while for the meteorological characteristics wind-statistics were created. Additional input parameters were the ground plan and the elevation of buildings. To simulate the airflow and the dispersion of pollutants a Computational Fluid Dynamics code called MISKAM was used. The background concentration was taken from the dataset of a nearby air quality monitoring station. According to vehicle counting the 5 roads of the roundabout have very different loads from 12 vehicles to more than 412 vehicles/hour. Three different grid systems were applied ranging from half million to 5 million cells. The difference in the results related to grid density was also evaluated. Wind speed distribution, wind turbulence and building wake flow patterns were identified by using the model. With the help of the simulation the NOx flow and dispersion of pollutants around the roundabout can be estimated and the critical locations with higher pollution concentration are presented. The results of the modelling can be more generalized and used in the design of the layout, development, traffic-control and environmental aspects of roundabouts located in small urban areas.

  10. Is improved lane keeping during cognitive load caused by increased physical arousal or gaze concentration toward the road center?

    PubMed

    Li, Penghui; Markkula, Gustav; Li, Yibing; Merat, Natasha

    2018-08-01

    Driver distraction is one of the main causes of motor-vehicle accidents. However, the impact on traffic safety of tasks that impose cognitive (non-visual) distraction remains debated. One particularly intriguing finding is that cognitive load seems to improve lane keeping performance, most often quantified as reduced standard deviation of lateral position (SDLP). The main competing hypotheses, supported by current empirical evidence, suggest that cognitive load improves lane keeping via either increased physical arousal, or higher gaze concentration toward the road center, but views are mixed regarding if, and how, these possible mediators influence lane keeping performance. Hence, a simulator study was conducted, with participants driving on a straight city road section whilst completing a cognitive task at different levels of difficulty. In line with previous studies, cognitive load led to increased physical arousal, higher gaze concentration toward the road center, and higher levels of micro-steering activity, accompanied by improved lane keeping performance. More importantly, during the high cognitive task, both physical arousal and gaze concentration changed earlier in time than micro-steering activity, which in turn changed earlier than lane keeping performance. In addition, our results did not show a significant correlation between gaze concentration and physical arousal on the level of individual task recordings. Based on these findings, various multilevel models for micro-steering activity and lane keeping performance were conducted and compared, and the results suggest that all of the mechanisms proposed by existing hypotheses could be simultaneously involved. In other words, it is suggested that cognitive load leads to: (i) an increase in arousal, causing increased micro-steering activity, which in turn improves lane keeping performance, and (ii) an increase in gaze concentration, causing lane keeping improvement through both (a) further increased micro-steering activity and (b) a tendency to steer toward the gaze target. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Design and hardware-in-loop implementation of collision avoidance algorithms for heavy commercial road vehicles

    NASA Astrophysics Data System (ADS)

    Rajaram, Vignesh; Subramanian, Shankar C.

    2016-07-01

    An important aspect from the perspective of operational safety of heavy road vehicles is the detection and avoidance of collisions, particularly at high speeds. The development of a collision avoidance system is the overall focus of the research presented in this paper. The collision avoidance algorithm was developed using a sliding mode controller (SMC) and compared to one developed using linear full state feedback in terms of performance and controller effort. Important dynamic characteristics such as load transfer during braking, tyre-road interaction, dynamic brake force distribution and pneumatic brake system response were considered. The effect of aerodynamic drag on the controller performance was also studied. The developed control algorithms have been implemented on a Hardware-in-Loop experimental set-up equipped with the vehicle dynamic simulation software, IPG/TruckMaker®. The evaluation has been performed for realistic traffic scenarios with different loading and road conditions. The Hardware-in-Loop experimental results showed that the SMC and full state feedback controller were able to prevent the collision. However, when the discrepancies in the form of parametric variations were included, the SMC provided better results in terms of reduced stopping distance and lower controller effort compared to the full state feedback controller.

  12. Bearing Capacity Assessment on low Volume Roads

    NASA Astrophysics Data System (ADS)

    Zariņš, A.

    2015-11-01

    A large part of Latvian road network consists of low traffic volume roads and in particular of roads without hard pavement. Unbounded pavements shows serious problems in the form of rutting and other deformations, which finally lead to weak serviceability and damage of the road structure after intensive exploitation periods. Traditionally, these problems have been associated with heavy goods transport, overloaded vehicles and their impact. To find the specific damaging factors causing road pavement deformations and evaluate their prevention possibilities, and establish conditions that will allow doing it, the study was carried out. The tire pressure has been set as the main factor of load. Two different tire pressures have been used in tests and their impacts were compared. The comparison was done using deflection measurements with LWD together with dielectric constant measurements in a road structure using percometer. Measurements were taken in the upper pavement structure layers at different depths during full-scale loading and in different moisture/temperature conditions. Advisable load intensity and load factors for heavy traffic according to road conditions were set based on the study results.

  13. 40 CFR 86.529-98 - Road load force and inertia weight determination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Road load force and inertia weight... Emission Regulations for 1978 and Later New Motorcycles; Test Procedures § 86.529-98 Road load force and... of this section. Velocity V is in km/h and force (F) is in newtons. The forces given by the equation...

  14. 40 CFR 86.129-00 - Road load power, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Road load power, test weight, and... Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.129-00 Road load... running loss testing. Paragraphs (e) and (f) of this section are applicable to vehicles from engine...

  15. 40 CFR 86.129-00 - Road load power, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Road load power, test weight, and... Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.129-00 Road load... running loss testing. Paragraphs (e) and (f) of this section are applicable to vehicles from engine...

  16. 40 CFR 86.129-00 - Road load power, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Road load power, test weight, and... Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.129-00 Road load... running loss testing. Paragraphs (e) and (f) of this section are applicable to vehicles from engine...

  17. 40 CFR 86.129-00 - Road load power, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Road load power, test weight, and... Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.129-00 Road load... running loss testing. Paragraphs (e) and (f) of this section are applicable to vehicles from engine...

  18. 40 CFR 86.129-00 - Road load power, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Road load power, test weight, and... Light-Duty Trucks and New Otto-Cycle Complete Heavy-Duty Vehicles; Test Procedures § 86.129-00 Road load... running loss testing. Paragraphs (e) and (f) of this section are applicable to vehicles from engine...

  19. 40 CFR 86.529-98 - Road load force and inertia weight determination.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Road load force and inertia weight... inertia weight determination. (a)(1) Road load as a function of speed is given by the following equation: F = A + CV2 (2) The values for coefficients A and C and the test inertia are given in Figure F98-9...

  20. 40 CFR 86.529-98 - Road load force and inertia weight determination.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Road load force and inertia weight... inertia weight determination. (a)(1) Road load as a function of speed is given by the following equation: F = A + CV2 (2) The values for coefficients A and C and the test inertia are given in Figure F98-9...

  1. 40 CFR 86.529-98 - Road load force and inertia weight determination.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Road load force and inertia weight... inertia weight determination. (a)(1) Road load as a function of speed is given by the following equation: F = A + CV2 (2) The values for coefficients A and C and the test inertia are given in Figure F98-9...

  2. 40 CFR 86.529-98 - Road load force and inertia weight determination.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Road load force and inertia weight... inertia weight determination. (a)(1) Road load as a function of speed is given by the following equation: F = A + CV2 (2) The values for coefficients A and C and the test inertia are given in Figure F98-9...

  3. Finite element analysis of steady and transiently moving/rolling nonlinear viscoelastic structure. III - Impact/contact simulations

    NASA Technical Reports Server (NTRS)

    Nakajima, Yukio; Padovan, Joe

    1987-01-01

    In a three-part series of papers, a generalized finite element methodology is formulated to handle traveling load problems involving large deformation fields in structure composed of viscoelastic media. The main thrust of this paper is to develop an overall finite element methodology and associated solution algorithms to handle the transient aspects of moving problems involving contact impact type loading fields. Based on the methodology and algorithms formulated, several numerical experiments are considered. These include the rolling/sliding impact of tires with road obstructions.

  4. A study on the characteristics of silt loading on paved roads in the Seoul metropolitan area using a mobile monitoring system.

    PubMed

    Han, Sehyun; Jung, Yong-Won

    2012-07-01

    This study is considered the first attempt to apply a mobile monitoring system to estimating silt loading on paved roads in a megacity such as the Seoul metropolitan area. Using a mobile monitoring system developed in 2005, we estimated silt loadings on representative paved roads in the Seoul metropolitan area, including the city of Incheon, over a period of 3 yr. The temporal and spatial characteristics of silt loading were investigated for the carefully selected roads that may reflect the characteristics of the cities of Seoul and Incheon. In this study, changes in the average silt loading values were investigated in terms of land use, the temporal resolution of data acquisition (i.e., seasonal, daily, three-hour scale), the road width or number of lanes, and rainfall, which may affect the characteristics of the average silt loading significantly. It was found that the advantages of using the mobile monitoring system are its ability to obtain a large quantity of silt loading data in a short period of time and over a wide area and its ability to create a silt loading map showing the relative magnitude of silt loading in relation to a specific location, which makes it possible to easily locate hot spots.

  5. [Dynamic road vehicle emission inventory simulation study based on real time traffic information].

    PubMed

    Huang, Cheng; Liu, Juan; Chen, Chang-Hong; Zhang, Jian; Liu, Deng-Guo; Zhu, Jing-Yu; Huang, Wei-Ming; Chao, Yuan

    2012-11-01

    The vehicle activity survey, including traffic flow distribution, driving condition, and vehicle technologies, were conducted in Shanghai. The databases of vehicle flow, VSP distribution and vehicle categories were established according to the surveyed data. Based on this, a dynamic vehicle emission inventory simulation method was designed by using the real time traffic information data, such as traffic flow and average speed. Some roads in Shanghai city were selected to conduct the hourly vehicle emission simulation as a case study. The survey results show that light duty passenger car and taxi are major vehicles on the roads of Shanghai city, accounting for 48% - 72% and 15% - 43% of the total flow in each hour, respectively. VSP distribution has a good relationship with the average speed. The peak of VSP distribution tends to move to high load section and become lower with the increase of average speed. Vehicles achieved Euro 2 and Euro 3 standards are majorities of current vehicle population in Shanghai. Based on the calibration of vehicle travel mileage data, the proportions of Euro 2 and Euro 3 standard vehicles take up 11% - 70% and 17% - 51% in the real-world situation, respectively. The emission simulation results indicate that the ratios of emission peak and valley for the pollutants of CO, VOC, NO(x) and PM are 3.7, 4.6, 9.6 and 19.8, respectively. CO and VOC emissions mainly come from light-duty passenger car and taxi, which has a good relationship with the traffic flow. NO(x) and PM emissions are mainly from heavy-duty bus and public buses and mainly concentrate in the morning and evening peak hours. The established dynamic vehicle emission simulation method can reflect the change of actual road emission and output high emission road sectors and hours in real time. The method can provide an important technical means and decision-making basis for transportation environment management.

  6. Assessment of burned coal shale properties based on cyclic load

    NASA Astrophysics Data System (ADS)

    Grygierek, Marcin; Kalisz, Piotr; Pacześniowski, Krzysztof; Pytlik, Andrzej; Zięba, Magdalena

    2018-04-01

    Road surfaces that are subjected to cyclic loads generated by vehicle wheels must meet the requirements concerning the durability in the assumed period of use. The durability of the layered pavement construction systems depends on the value and frequency of the load as well as on the mechanical features of its individual layers. Layers of unbound, mechanically stabilized mixtures are a significant aspect of surfaces that are susceptible. Mixtures of this type can be applied both to the subgrade layers as well as to the bottom pavement layers, including the improved course. Considering the cyclic nature of the load on the surface of the entire system, mechanically stabilized layers are subject to continuous, but slow, densification during the period of use, which results in the formation of permanent deformations and so-called structural ruts. Post-mining waste is frequently used in road construction. which is the so-called burned shale that can be used for the bottom layers of the surface and layers of the improved subgrade (soil replacement). This material was the subject of the analysis. The evaluation was based mainly on the results of pilot studies covering cyclic loads of the layer/course made of the so-called red shale. The applied research method was aimed at preliminary assessment of its suitability for the assessment of the behaviour of the disintegrated medium under the conditions of test loads simulating the movement of vehicles.

  7. Get In and Get Out: Assessing Stream Sediment Loading from Short Duration Forest Harvest Operations and Rapid Haul Road Decommissioning.

    NASA Astrophysics Data System (ADS)

    Corrigan, A.; Silins, U.; Stone, M.

    2016-12-01

    Best management practices (BMPs) and associated erosion control measures for mitigating sediment impacts from forestry roads and road-stream crossings are well documented. While rapid road decommissioning after forestry operations may serve to limit broader impacts on sediment production in high value headwater streams, few studies have evaluated the combined effects of accelerated harvest operations and rapid retirement of logging roads and road-stream crossings on stream sediment. The objectives of this study were to evaluate the initial impacts of these strategies on fine sediment loading and fate during a short duration harvesting operation in 3 headwater sub-catchments in the southwestern Rocky Mountains of Alberta, Canada. A multi-pronged sampling approach (ISCOs, event focused grab sampling, continuous wash load sampling, and stream bed sediment intrusion measurements) was used to measure sediment loading and deposition in streambeds upstream and downstream of road-stream bridge crossings during harvest operations (2015) and after road and bridge crossing retirement (2016). Sediment production from forestry roads was generally much lower than has been reported from other studies in similar settings. Average total suspended solids (TSS) downstream of the bridge crossings were actually lower (-3.28 g/L; -0.704 g/L) than upstream of two bridge crossings while in-stream sediment sources contributed to elevated sediment downstream of a third road-stream crossing. Minimal in stream sediment impacts from forest harvest and road-stream crossings was likely a reflection of combined factors including a) employment of erosion control BMPs to roads and bridge crossings, b) rapid decommissioning of roads and crossings to limit exposure of linear land disturbance features, and c) drier El Niño climatic conditions during the study.

  8. Results of the ETV-1 breadboard tests under steady-state and transient conditions. [conducted in the NASA-LeRC Road Load Simulator

    NASA Technical Reports Server (NTRS)

    Sargent, N. B.; Dustin, M. O.

    1981-01-01

    Steady state tests were run to characterize the system and component efficiencies over the complete speed-torque capabilities of the propulsion system in both motoring and regenerative modes of operation. The steady state data were obtained using a battery simulator to separate the effects on efficiency caused by changing battery state-of-charge and component temperature. Transient tests were performed to determine the energy profiles of the propulsion system operating over the SAE J227a driving schedules.

  9. California bearing ratio analysis on Kunduran - Goa Terawangan road, Blora Regency

    NASA Astrophysics Data System (ADS)

    Lashari, Widodo, Aris; Azizah, Nur

    2018-03-01

    The study about California Bearing Ratio on subgrade is required as the road infrastructure. Some researchers has conducted studies about California Bearing Ratio in both laboratory and the field to figure out the load bearing capacity of the existing soil in the field. The Kunduran - Goa Terawang road is a regency road which connects the Kunduran district and Todanan district. The length of the Kunduran - Goa Terawang is 11,44 km with the endpoint identifier (STA 0 road) from T intersection 3/49 on the provincial road km 25. The Kunduran - Goa Terawang road has experienced damaged from time to time. Therefore, the condition of load bearing capacity on the subgrade must be analysed. The value of load bearing capacity of the subgrade on the road. The California Bearing Ratio had to be conducted to figure out the value. The California Bearing Ratio test was conducted in two ways, 1) the laboratory California Bearing Ratio testing and the field California Bearing Ration using the Dynamic Cone Penetrometer. The testing was conducted in three points, STA 0+250, STA 0+500, dan STA 0+750.

  10. Explicit Nonlinear Finite Element Geometric Analysis of Parabolic Leaf Springs under Various Loads

    PubMed Central

    Kong, Y. S.; Omar, M. Z.; Chua, L. B.; Abdullah, S.

    2013-01-01

    This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE) method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability. PMID:24298209

  11. Explicit nonlinear finite element geometric analysis of parabolic leaf springs under various loads.

    PubMed

    Kong, Y S; Omar, M Z; Chua, L B; Abdullah, S

    2013-01-01

    This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE) method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability.

  12. Effects of road dust on the growth characteristics of Sophora japonica L. seedlings.

    PubMed

    Bao, Le; Qu, Laiye; Ma, Keming; Lin, Lin

    2016-08-01

    Road dust is one of the most common pollutants and causes a series of negative effects on plant physiology. Dust's impacts on plants can be regarded as a combination of load, composition and grain size impacts on plants; however, there is a lack of integrated dust effect studies involving these three aspects. In our study, Sophora japonica seedlings were artificially dusted with road dust collected from the road surface of Beijing so that we could study the impacts of this dust on nitrogen/carbon allocation, biomass allocation and photosynthetic pigments from the three aspects of composition, load and grain size. The results showed that the growth characteristics of S. japonica seedlings were mostly influenced by dust composition and load. Leaf N, root-shoot ratio and chlorophyll a/b were significantly affected by dust composition and load; leaf C/N, shoot biomass, total chlorophyll and carotenoid were significantly affected by dust load; stem N and stem C/N were significantly affected by dust composition; while the dust grain size alone did not affect any of the growth characteristics. Road dust did influence the growth characteristics more extensively than loam. Therefore, a higher dust load could increase the differences between road dust and loam treatments. The elements in dust are well correlated to the shoot N, shoot C/N, and root-shoot ratio of S. japonica seedlings. This knowledge could benefit the management of urban green spaces. Copyright © 2016. Published by Elsevier B.V.

  13. Prognosis of flow conditions for de-centralized seepage of rainwater from roads

    NASA Astrophysics Data System (ADS)

    Meyer, Martin; Hasan, Issa; Sallwey, Jana; Graeber, Peter-Wolfgang

    2013-04-01

    Urbanization programs that include the construction of new settlements or roads lead to an increase in surface sealing. Conventional road drainage is being carried out by a rainwater sewage system coupled with collection and detention basins. This leads to local decreases in evaporation and groundwater recharge, disturbing the natural local water balance. The increased number of climate changed induced extreme precipitation events leads to a higher risk of road floodings as a result of a failure of these systems. Furthermore, the treatment of the discharge loaded with contaminants (such as heavy metals and MTBE) is resolved neither ecologically nor technologically. By using a natural, effective and sustainable evaporation and drainage strategy it is possible to reduce the probability of road floodings, to restore the natural local water balance and to establish ecologically and economically more beneficial rainwater drainage. By using PCSiWaPro®, a simulation tool for unsaturated soil zone processes developed at the Institute of Waste Management and the Technical University of Dresden, the effects of different atmospheric, hydrological and hydrogeological parameters and system conditions on the subsurface drainage flow conditions in the vicinity of a typical German highway road were studied. Special attention was given to the influence of extreme precipitation events on the drainage time at differently tilted parts of the surface, on surface drainages from lateral noise-protection barriers and on the probability of road surface underwashing. Differently constructed upper soil stratifications were tested for their ability to quickly drain water into the ground, which, besides the reduced risk of road flooding, also influence the duration time for the drainage water in each soil layer. Individual rainwater infiltration rates were applied for different regions of the model. The behaviours of three different types of soil (coarse sand, slightly silty sand and medium silty sand) were tested for their applicability as road base materials. The simulation results showed that for extreme precipitation events, the optimized decentralized road drainage system was able to discharge the accumulated rainwater. In future applications, the unsaturated flow model will be extended to a reactive transport model in order to develop strategies for optimal local drainage system design with special regard to natural purification features of different soil layer types. Additionally, PCSiWaPro® can be coupled to a groundwater model to simulate the influence of potential local groundwater contamination by road discharge on the whole underlying aquifer.

  14. Development of laboratory testing facility for evaluation of base-soil behavior under repeated loading : phase 1 : feasibility study.

    DOT National Transportation Integrated Search

    2005-02-01

    Accelerated load testing of paved and unpaved roads is the application of a large number of load repetitions in a short period of time. This type of testing is an economic way to determine the behavior of roads and compare different materials, struct...

  15. 30 CFR 77.1600 - Loading and haulage; general.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... permitted on haulage roads and at loading or dumping locations. (b) Traffic rules, signals, and warning signs shall be standardized at each mine and posted. (c) Where side or overhead clearances on any haulage road or at any loading or dumping location at the mine are hazardous to mine workers, such areas...

  16. 30 CFR 77.1600 - Loading and haulage; general.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... permitted on haulage roads and at loading or dumping locations. (b) Traffic rules, signals, and warning signs shall be standardized at each mine and posted. (c) Where side or overhead clearances on any haulage road or at any loading or dumping location at the mine are hazardous to mine workers, such areas...

  17. 30 CFR 77.1600 - Loading and haulage; general.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... permitted on haulage roads and at loading or dumping locations. (b) Traffic rules, signals, and warning signs shall be standardized at each mine and posted. (c) Where side or overhead clearances on any haulage road or at any loading or dumping location at the mine are hazardous to mine workers, such areas...

  18. 30 CFR 77.1600 - Loading and haulage; general.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... permitted on haulage roads and at loading or dumping locations. (b) Traffic rules, signals, and warning signs shall be standardized at each mine and posted. (c) Where side or overhead clearances on any haulage road or at any loading or dumping location at the mine are hazardous to mine workers, such areas...

  19. 30 CFR 77.1600 - Loading and haulage; general.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... permitted on haulage roads and at loading or dumping locations. (b) Traffic rules, signals, and warning signs shall be standardized at each mine and posted. (c) Where side or overhead clearances on any haulage road or at any loading or dumping location at the mine are hazardous to mine workers, such areas...

  20. 36 CFR 4.11 - Load, weight and size limits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... INTERIOR VEHICLES AND TRAFFIC SAFETY § 4.11 Load, weight and size limits. (a) Vehicle load, weight and size limits established by State law apply to a vehicle operated on a park road. However, the superintendent may designate more restrictive limits when appropriate for traffic safety or protection of the road...

  1. Frequency of Loaded Road March Training and Performance on a Loaded Road March

    DTIC Science & Technology

    1990-04-01

    heart rate through the use of beta - blockers can substantially improve shooting accuracy (29, 44). Post road march decrements in the grenade throw may...the road march. An Increase in body tremors due to fatigue or an elevated post exercise heart rate may account for this. Whole body sway while aiming...a rifle is substantially increased even after a short period of exercise (39) and this may effect accuracy. Muscle tremors increase after brief or

  2. Roads & loads : finding a balance.

    DOT National Transportation Integrated Search

    2006-01-01

    Striking a balance between the needs of commerce to carry heavy loads on roads and the need to preserve the significant investment in our transportation infrastructure is a challenging process. There are compelling needs from both sides of the pictur...

  3. Vehicle anti-rollover control strategy based on load transferring rate

    NASA Astrophysics Data System (ADS)

    Dai, W. T.; Du, H. Q.; Zhang, L.

    2018-03-01

    When vehicles is drived on a low adhesion road or going on a high speed and sharp turn, it is prone to product some lateral stability problems, such as lateral sideslip or rollover. In order to improve the vehicle anti-rollover stability under these limited conditions, a SUV vehicle model with high mass center was built based on the software of CarSim and the rollover stability controller was designed using the static threshold value method for the lateral load transferring rate (LTR). The simulations are shown that the vehicle anti-rollover stability under limit conditions is improved using the SUV model.

  4. The Effect of Low-Frequency Road Noise on Driver Sleepiness and Performance

    PubMed Central

    Anund, Anna; Lahti, Eva; Fors, Carina; Genell, Anders

    2015-01-01

    It is a well-known fact today that driver sleepiness is a contributory factor in crashes. Factors considered as sleepiness contributor are mostly related to time of the day, hours being awake and hours slept. Factors contributing to active and passive fatigue are mostly focusing on the level of cognitive load. Less is known what role external factors, e.g. type of road, sound/noise, vibrations etc., have on the ability to stay awake both under conditions of sleepiness and under active or passive fatigue. The aim of this moving base driving simulator study with 19 drivers participating in a random order day and night time, was to evaluate the effect of low-frequency road noise on driver sleepiness and performance, including both long-term and short-term effects. The results support to some extent the hypothesis that road-induced interior vehicle sound affects driving performance and driver sleepiness. Increased low-frequency noise helps to reduce speed during both day- and night time driving, but also contributes to increase the number of lane crossings during night time. PMID:25874883

  5. A LQR-Based Controller with Estimation of Road Bank for Improving Vehicle Lateral and Rollover Stability via Active Suspension

    PubMed Central

    Sanz, Susana

    2017-01-01

    In this article, a Linear Quadratic Regulator (LQR) lateral stability and rollover controller has been developed including as the main novelty taking into account the road bank angle and using exclusively active suspension for both lateral stability and rollover control. The main problem regarding the road bank is that it cannot be measured by means of on-board sensors. The solution proposed in this article is performing an estimation of this variable using a Kalman filter. In this way, it is possible to distinguish between the road disturbance component and the vehicle’s roll angle. The controller’s effectiveness has been tested by means of simulations carried out in TruckSim, using an experimentally-validated vehicle model. Lateral load transfer, roll angle, yaw rate and sideslip angle have been analyzed in order to quantify the improvements achieved on the behavior of the vehicle. For that purpose, these variables have been compared with the results obtained from both a vehicle that uses passive suspension and a vehicle using a fuzzy logic controller. PMID:29027910

  6. The effect of low-frequency road noise on driver sleepiness and performance.

    PubMed

    Anund, Anna; Lahti, Eva; Fors, Carina; Genell, Anders

    2015-01-01

    It is a well-known fact today that driver sleepiness is a contributory factor in crashes. Factors considered as sleepiness contributor are mostly related to time of the day, hours being awake and hours slept. Factors contributing to active and passive fatigue are mostly focusing on the level of cognitive load. Less is known what role external factors, e.g. type of road, sound/noise, vibrations etc., have on the ability to stay awake both under conditions of sleepiness and under active or passive fatigue. The aim of this moving base driving simulator study with 19 drivers participating in a random order day and night time, was to evaluate the effect of low-frequency road noise on driver sleepiness and performance, including both long-term and short-term effects. The results support to some extent the hypothesis that road-induced interior vehicle sound affects driving performance and driver sleepiness. Increased low-frequency noise helps to reduce speed during both day- and night time driving, but also contributes to increase the number of lane crossings during night time.

  7. Crash Test of Three Cessna 172 Aircraft at NASA Langley Research Center's Landing and Impact Research Facility

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.

    2015-01-01

    During the summer of 2015, three Cessna 172 aircraft were crash tested at the Landing and Impact Research Facility (LandIR) at NASA Langley Research Center (LaRC). The three tests simulated three different crash scenarios. The first simulated a flare-to-stall emergency or hard landing onto a rigid surface such as a road or runway, the second simulated a controlled flight into terrain with a nose down pitch on the aircraft, and the third simulated a controlled flight into terrain with an attempt to unsuccessfully recover the aircraft immediately prior to impact, resulting in a tail strike condition. An on-board data acquisition system captured 64 channels of airframe acceleration, along with acceleration and load in two onboard Hybrid II 50th percentile Anthropomorphic Test Devices, representing the pilot and co-pilot. Each test contained different airframe loading conditions and results show large differences in airframe performance. This paper presents test methods used to conduct the crash tests and will summarize the airframe results from the test series.

  8. MobRISK: a model for assessing the exposure of road users to flash flood events

    NASA Astrophysics Data System (ADS)

    Shabou, Saif; Ruin, Isabelle; Lutoff, Céline; Debionne, Samuel; Anquetin, Sandrine; Creutin, Jean-Dominique; Beaufils, Xavier

    2017-09-01

    Recent flash flood impact studies highlight that road networks are often disrupted due to adverse weather and flash flood events. Road users are thus particularly exposed to road flooding during their daily mobility. Previous exposure studies, however, do not take into consideration population mobility. Recent advances in transportation research provide an appropriate framework for simulating individual travel-activity patterns using an activity-based approach. These activity-based mobility models enable the prediction of the sequence of activities performed by individuals and locating them with a high spatial-temporal resolution. This paper describes the development of the MobRISK microsimulation system: a model for assessing the exposure of road users to extreme hydrometeorological events. MobRISK aims at providing an accurate spatiotemporal exposure assessment by integrating travel-activity behaviors and mobility adaptation with respect to weather disruptions. The model is applied in a flash-flood-prone area in southern France to assess motorists' exposure to the September 2002 flash flood event. The results show that risk of flooding mainly occurs in principal road links with considerable traffic load. However, a lag time between the timing of the road submersion and persons crossing these roads contributes to reducing the potential vehicle-related fatal accidents. It is also found that sociodemographic variables have a significant effect on individual exposure. Thus, the proposed model demonstrates the benefits of considering spatiotemporal dynamics of population exposure to flash floods and presents an important improvement in exposure assessment methods. Such improved characterization of road user exposures can present valuable information for flood risk management services.

  9. Why are some animal populations unaffected or positively affected by roads?

    PubMed

    Rytwinski, Trina; Fahrig, Lenore

    2013-11-01

    In reviews on effects of roads on animal population abundance we found that most effects are negative; however, there are also many neutral and positive responses [Fahrig and Rytwinski (Ecol Soc 14:21, 2009; Rytwinski and Fahrig (Biol Conserv 147:87-98, 2012)]. Here we use an individual-based simulation model to: (1) confirm predictions from the existing literature of the combinations of species traits and behavioural responses to roads that lead to negative effects of roads on animal population abundance, and (2) improve prediction of the combinations of species traits and behavioural responses to roads that lead to neutral and positive effects of roads on animal population abundance. Simulations represented a typical situation in which road mitigation is contemplated, i.e. rural landscapes containing a relatively low density (up to 1.86 km/km(2)) of high-traffic roads, with continuous habitat between the roads. In these landscapes, the simulations predict that populations of species with small territories and movement ranges, and high reproductive rates, i.e. many small mammals and birds, should not be reduced by roads. Contrary to previous suggestions, the results also predict that populations of species that obtain a resource from roads (e.g. vultures) do not increase with increasing road density. In addition, our simulations support the predation release hypothesis for positive road effects on prey (both small- and large-bodied prey), whereby abundance of a prey species increased with increasing road density due to reduced predation by generalist road-affected predators. The simulations also predict an optimal road density for the large-bodied prey species if it avoids roads or traffic emissions. Overall, the simulation results suggest that in rural landscapes containing high-traffic roads, there are many species for which road mitigation may not be necessary; mitigation efforts should be tailored to the species that show negative population responses to roads.

  10. Road simulation for four-wheel vehicle whole input power spectral density

    NASA Astrophysics Data System (ADS)

    Wang, Jiangbo; Qiang, Baomin

    2017-05-01

    As the vibration of running vehicle mainly comes from road and influence vehicle ride performance. So the road roughness power spectral density simulation has great significance to analyze automobile suspension vibration system parameters and evaluate ride comfort. Firstly, this paper based on the mathematical model of road roughness power spectral density, established the integral white noise road random method. Then in the MATLAB/Simulink environment, according to the research method of automobile suspension frame from simple two degree of freedom single-wheel vehicle model to complex multiple degrees of freedom vehicle model, this paper built the simple single incentive input simulation model. Finally the spectrum matrix was used to build whole vehicle incentive input simulation model. This simulation method based on reliable and accurate mathematical theory and can be applied to the random road simulation of any specified spectral which provides pavement incentive model and foundation to vehicle ride performance research and vibration simulation.

  11. Improving foundation design in rock : load test at Burma Road Overpass, final report, December 2009.

    DOT National Transportation Integrated Search

    2009-12-01

    This report describes the results of a bi-directional load test on a drilled shaft foundation in weak sandstone. The test was conducted in : conjunction with construction of a new bridge at Burma Road Overpass on I-90 in Gillette, Wyoming. The purpos...

  12. Evaluation of the base/subgrade soil under repeated loading : phase II, in-box and ALF cyclic plate load tests [tech summary].

    DOT National Transportation Integrated Search

    2012-03-01

    The inadequacy of many existing roads due to rapid growth in traffic volume provides a motivation for exploring alternatives to : existing methods of constructing and rehabilitating roads. The use of geosynthetics to stabilize and reinforce paved and...

  13. Measurement of Vehicle Tire-to-Road Coefficient of Friction with a Portable Microcomputerized Transducer.

    DTIC Science & Technology

    1982-08-01

    Sliding Rubber and the Load Dependance of Road Tyre Friction," The Physics of Tire Tractio,’. Theory, and Experiment (Hays, D. F., and Brown, A. L...Saturation of Sliding Rubber and the Load Dependance of Road Tyre Friction," The Physics of Tire Traction, Theory, and Expe-iment (Hays, D. F., and...surfaces could be identified and evaluated before accidents happen or runway surfaces could be evaluated to determine if rubber or other contaminant

  14. Elements in Mud and Snow in the Vicinity of the DeLong Mountain Regional Transportation System Road, Red Dog Mine, and Cape Krusenstern National Monument, Alaska, 2005-06

    USGS Publications Warehouse

    Brumbaugh, William J.; May, Thomas W.

    2008-01-01

    A small number of mud, road bed soil, and snow samples were collected in 2005 and 2006 to assess metal concentrations and loadings to areas adjacent to the DeLong Mountain Regional Transportation System (DMTS) road in northwest Alaska. The DMTS road is used by large trucks to transport lead and zinc concentrates from Red Dog Mine to the shipping facility at Red Dog Port; it traverses 32 kilometers of land in Cape Krusenstern National Monument (CAKR). Mud collected in the summer of 2005 from wheel-wells of two passenger vehicles used for transport between Red Dog Mine and the port facility were enriched in cadmium, lead, and zinc by factors of about 200 to 800 as compared with mud collected from a vehicle stationed in Kotzebue, Alaska, whereas DMTS road bed soil samples were enriched by factors of 6 to 12. Thus, as of 2005, dispersal of mine ore wastes or concentrates by vehicles appeared to remain a potential source of metals along the DMTS road. Compared to snow samples obtained near a gravel road located near Kotzebue, Alaska, metal loadings estimated from individual snow samples collected in CAKR in April 2006 near three creeks, 13 to 50 meters from the road, were greater by factors of 13 to 316 for cadmium, 28 to 589 for lead, and 8 to 195 for zinc. When averaged for all three creek locations, mean loadings of cadmium, lead, and zinc calculated from snow samples collected at a nominal distance of 15 meters to the north of the road were 0.63, 34, and 89 milligrams of metal per square meter, respectively. Variability of particulate and metal loadings between individual samples and the three creek locations probably was affected by localized meteorological conditions and micro-topography on the snow drift and scour patterns, but road orientation on attainable truck speeds also might have been a factor. Results indicated that the ?port effect?, previously attributed to fugitive metal-enriched dusts stemming from concentrate transfer operations at the port facility, was not necessarily an important factor affecting spatial differences of metals deposition in snow along the road in CAKR during winter 2005?06. The average metal content of particulates in 2005?06 snow samples was slightly less than that of snow samples collected by the U.S. Geological Survey in CAKR at three near-road locations in April 2003. Mean metals concentrations in 2006 snow particulates were about three times greater than in the road bed soils that were sampled in 2005; however, the fraction of annual metals loadings occurring in winter as compared to the remainder of the year was not readily determined by these data. Although procedures have been implemented in recent years to reduce the quantities of metal-enriched fugitive dusts, particulates dispersed near the road during the winter of 2005?06 were enriched in metals and these particulates contributed considerable metal loadings to the nearby terrain.

  15. Characterization of the near-term electric vehicle (ETV-1) breadboard propulsion system over the SAE J227a driving schedule D

    NASA Technical Reports Server (NTRS)

    Sargent, N. B.; Dustin, M. O.

    1981-01-01

    The electric test vehicle one (ETV-1) was built from the ground up with present state of the art technology. Two vehicles were built and are presently being evaluated by NASA's Jet Propulsion Laboratory (JPL). A duplicate set of propulsion system components was built, mounted on a breadboard, and delivered to NASA's Lewis Research Center for testing on the road load simulator (RLS). Driving cycle tests completed on the system are described.

  16. Identification of the mechanical properties of bicycle tyres for modelling of bicycle dynamics

    NASA Astrophysics Data System (ADS)

    Doria, Alberto; Tognazzo, Mauro; Cusimano, Gianmaria; Bulsink, Vera; Cooke, Adrian; Koopman, Bart

    2013-03-01

    Advanced simulation of the stability and handling properties of bicycles requires detailed road-tyre contact models. In order to develop these models, in this study, four bicycle tyres are tested by means of a rotating disc machine with the aim of measuring the components of tyre forces and torques that influence the safety and handling of bicycles. The effect of inflation pressure and tyre load is analysed. The measured properties of bicycle tyres are compared with those of motorcycle tyres.

  17. In-simulator training of driving abilities in a person with a traumatic brain injury.

    PubMed

    Gamache, Pierre-Luc; Lavallière, Martin; Tremblay, Mathieu; Simoneau, Martin; Teasdale, Normand

    2011-01-01

    This study reports the case of a 23-year-old woman (MC) who sustained a severe traumatic brain injury in 2004. After her accident, her driving license was revoked. Despite recovering normal neuropsychological functions in the following years, MC was unable to renew her license, failing four on-road evaluations assessing her fitness to drive. In hope of an eventual license renewal, MC went through an in-simulator training programme in the laboratory in 2009. The training programme aimed at improving features of MC's driving behaviour that were identified as being problematic in prior on-road evaluations. To do so, proper driving behaviour was reinforced via driving-specific feedback provided during the training sessions. After 25 sessions in the simulator (over a period of 4 months), MC significantly improved various components of her driving. Notably, compared to early sessions, later ones were associated with a reduced cognitive load, less jerky speed profiles when stopping at intersections and better vehicle control and positioning. A 1-year retention test showed most of these improvements were consistent. The learning principles underlying well conducted simulator-based education programmes have a strong scientific basis. A simulator training programme like this one represents a promising avenue for driving rehabilitation. It allows individuals without a driving license to practice and improve their skills in a safe and realistic environment.

  18. Comparison of heavy metal loads in stormwater runoff from major and minor urban roads using pollutant yield rating curves.

    PubMed

    Davis, Brett; Birch, Gavin

    2010-08-01

    Trace metal export by stormwater runoff from a major road and local street in urban Sydney, Australia, is compared using pollutant yield rating curves derived from intensive sampling data. The event loads of copper, lead and zinc are well approximated by logarithmic relationships with respect to total event discharge owing to the reliable appearance of a first flush in pollutant mass loading from urban roads. Comparisons of the yield rating curves for these three metals show that copper and zinc export rates from the local street are comparable with that of the major road, while lead export from the local street is much higher, despite a 45-fold difference in traffic volume. The yield rating curve approach allows problematic environmental data to be presented in a simple yet meaningful manner with less information loss. Copyright 2010 Elsevier Ltd. All rights reserved.

  19. Assessing the driving performance of older adult drivers: on-road versus simulated driving.

    PubMed

    Lee, Hoe C; Cameron, Don; Lee, Andy H

    2003-09-01

    To validate a laboratory-based driving simulator in measuring on-road driving performance, 129 older adult drivers were assessed with both the simulator and an on-road test. The driving performance of the participants was gauged by appropriate and reliable age-specific assessment criteria, which were found to be negatively correlated with age. Using principal component analysis, two performance indices were developed from the criteria to represent the overall performance in simulated driving and the on-road assessment. There was significant positive association between the two indices, with the simulated driving performance index explaining over two-thirds of the variability of the on-road driving performance index, after adjustment for age and gender of the drivers. The results supported the validity of the driving simulator and it is a safer and more economical method than the on-road testing to assess the driving performance of older adult drivers.

  20. Comparing treatment effects of oral THC on simulated and on-the-road driving performance: testing the validity of driving simulator drug research.

    PubMed

    Veldstra, J L; Bosker, W M; de Waard, D; Ramaekers, J G; Brookhuis, K A

    2015-08-01

    The driving simulator provides a safe and controlled environment for testing driving behaviour efficiently. The question is whether it is sensitive to detect drug-induced effects. The primary aim of the current study was to investigate the sensitivity of the driving simulator for detecting drug effects. As a case in point, we investigated the dose-related effects of oral ∆(9)-tetrahydrocannabinol (THC), i.e. dronabinol, on simulator and on-the-road driving performance in equally demanding driving tasks. Twenty-four experienced driver participants were treated with dronabinol (Marinol®; 10 and 20 mg) and placebo. Dose-related effects of the drug on the ability to keep a vehicle in lane (weaving) and to follow the speed changes of a lead car (car following) were compared within subjects for on-the-road versus in-simulator driving. Additionally, the outcomes of equivalence testing to alcohol-induced effects were investigated. Treatment effects found on weaving when driving in the simulator were comparable to treatment effects found when driving on the road. The effect after 10 mg dronabinol was however less strong in the simulator than on the road and inter-individual variance seemed higher in the simulator. There was, however, a differential treatment effect of dronabinol on reactions to speed changes of a lead car (car following) when driving on the road versus when driving in the simulator. The driving simulator was proven to be sensitive for demonstrating dronabinol-induced effects particularly at higher doses. Treatment effects of dronabinol on weaving were comparable with driving on the road but inter-individual variability seemed higher in the simulator than on the road which may have potential effects on the clinical inferences made from simulator driving. Car following on the road and in the simulator were, however, not comparable.

  1. 36 CFR 4.11 - Load, weight and size limits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... limits established by State law apply to a vehicle operated on a park road. However, the superintendent may designate more restrictive limits when appropriate for traffic safety or protection of the road... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Load, weight and size limits...

  2. 36 CFR 4.11 - Load, weight and size limits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... limits established by State law apply to a vehicle operated on a park road. However, the superintendent may designate more restrictive limits when appropriate for traffic safety or protection of the road... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Load, weight and size limits...

  3. 36 CFR 4.11 - Load, weight and size limits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... limits established by State law apply to a vehicle operated on a park road. However, the superintendent may designate more restrictive limits when appropriate for traffic safety or protection of the road... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Load, weight and size limits...

  4. 36 CFR 4.11 - Load, weight and size limits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... limits established by State law apply to a vehicle operated on a park road. However, the superintendent may designate more restrictive limits when appropriate for traffic safety or protection of the road... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Load, weight and size limits...

  5. 40 CFR 86.129-80 - Road load power, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Road load power, test weight, and inertia weight class determination. 86.129-80 Section 86.129-80 Protection of Environment ENVIRONMENTAL... power, test weight, and inertia weight class determination. (a) [Reserved] (b) Power absorption unit...

  6. Impact of traffic intensity and pavement aggregate size on road dust particles loading

    NASA Astrophysics Data System (ADS)

    Amato, F.; Pandolfi, M.; Alastuey, A.; Lozano, A.; Contreras González, J.; Querol, X.

    2013-10-01

    Road dust emissions severely hamper PM10 urban air quality and their burden is expected to increase relatively to primary motor exhaust emissions. Beside the large influence of climate and meteorology, the emission potential varies widely also from one road to another due to numerous factors such as traffic conditions, pavement type and external sources. Nevertheless none of these factors is sufficiently known for a reliable description in emission modelling and for decision making in air quality management. In this study we carried out intensive road dust measurement campaigns in South Spain, with the aim of investigating the relationship between emission potential (i.e. road dust load) and traffic intensity, pavement aggregate size and distance from braking zones. Results indicate that, while no impact from braking activity can be drawn on the bulk road dust mass, an increase in traffic intensity or mean pavement aggregate size clearly reduce the single vehicle emission potential.

  7. ATD Occupant Responses from Three Full-Scale General Aviation Crash Tests

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.; Annett, Martin S.

    2016-01-01

    During the summer of 2015, three Cessna 172 General Aviation (GA) aircraft were crash tested at the Landing and Impact Research (LandIR) Facility at NASA Langley Research Center (LaRC). Three different crash scenarios were represented. The first test simulated a flare-to-stall emergency or hard landing onto a rigid surface such as a road or runway. The second test simulated a controlled flight into terrain with a nose down pitch of the aircraft, and the third test simulated a controlled flight into terrain with an attempt to unsuccessfully recover the aircraft immediately prior to impact, resulting in a tail strike condition. An on-board data acquisition system (DAS) captured 64 channels of airframe acceleration, along with accelerations and loads in two onboard Hybrid II 50th percentile Anthropomorphic Test Devices (ATDs) representing the pilot and copilot. Each of the three tests contained different airframe loading conditions and different types of restraints for both the pilot and co-pilot ATDs. The results show large differences in occupant response and restraint performance with varying likelihoods of occupant injury.

  8. Road dust emissions from paved roads measured using different mobile systems.

    PubMed

    Pirjola, Liisa; Johansson, Christer; Kupiainen, Kaarle; Stojiljkovic, Ana; Karlsson, Hans; Hussein, Tareq

    2010-12-01

    Very few real-world measurements of road dust suspension have been performed to date. This study compares two different techniques (referred to as Sniffer and Emma) to measure road dust emissions. The main differences between the systems are the construction of the inlet, different instruments for recording particulate matter (PM) levels, and different loads on the wheel axes (the weight of Sniffer was much higher than that of Emma). Both systems showed substantial small-scale variations of emission levels along the road, likely depending on-road surface conditions. The variations observed correlated quite well, and the discrepancies are likely a result of variations in dust load on the road surface perpendicular to the driving direction that cause variations in the measurements depending on slightly different paths driven by the two vehicles. Both systems showed a substantial influence on the emission levels depending on the type of tire used. The summer tire showed much lower suspension than the winter tires (one nonstudded and one studded). However, the relative importance of the nonstudded versus studded tire was rather different. For the ratio of studded/nonstudded, Emma shows higher values on all road sections compared with Sniffer. Both techniques showed increased emission levels with increasing vehicle speed. When the speed increased from 50 to 80 km hr(-1), the relative concentrations increased by 30-170% depending on the tire type and dust load. However, for road sections that were very dirty, Sniffer showed a much higher relative increase in the emission level with the nonstudded tire. Sniffer's absolute concentrations were mostly higher than Emma's. Possible reasons for the differences are discussed in the paper. Both systems can be used for studying relative road dust emissions and for designing air quality management strategies.

  9. Additional road markings as an indication of speed limits: results of a field experiment and a driving simulator study.

    PubMed

    Daniels, Stijn; Vanrie, Jan; Dreesen, An; Brijs, Tom

    2010-05-01

    Although speed limits are indicated by road signs, road users are not always aware, while driving, of the actual speed limit on a given road segment. The Roads and Traffic Agency developed additional road markings in order to support driver decisions on speed on 70 km/h roads in Flanders-Belgium. In this paper the results are presented of two evaluation studies, both a field study and a simulator study, on the effects of the additional road markings on speed behaviour. The results of the field study showed no substantial effect of the markings on speed behaviour. Neither did the simulator study, with slightly different stimuli. Nevertheless an effect on lateral position was noticed in the simulator study, showing at least some effect of the markings. The role of conspicuity of design elements and expectations towards traffic environments is discussed. Both studies illustrate well some strengths and weaknesses of observational field studies compared to experimental simulator studies. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  10. Forest roads, chronic turbidity, and salmon

    Treesearch

    L. M. Reid

    1998-01-01

    Certain impacts of forest roads on habitats used by anadromous salmonids are widely recognized and well-understood: road-related landslides increase sediment loads and modify channel morphology, and culverts restrict access to parts of the channel network. Other influences are less obvious, but may be even more pervasive. For example, road-related erosion significantly...

  11. New method for distance-based close following safety indicator.

    PubMed

    Sharizli, A A; Rahizar, R; Karim, M R; Saifizul, A A

    2015-01-01

    The increase in the number of fatalities caused by road accidents involving heavy vehicles every year has raised the level of concern and awareness on road safety in developing countries like Malaysia. Changes in the vehicle dynamic characteristics such as gross vehicle weight, travel speed, and vehicle classification will affect a heavy vehicle's braking performance and its ability to stop safely in emergency situations. As such, the aim of this study is to establish a more realistic new distance-based safety indicator called the minimum safe distance gap (MSDG), which incorporates vehicle classification (VC), speed, and gross vehicle weight (GVW). Commercial multibody dynamics simulation software was used to generate braking distance data for various heavy vehicle classes under various loads and speeds. By applying nonlinear regression analysis to the simulation results, a mathematical expression of MSDG has been established. The results show that MSDG is dynamically changed according to GVW, VC, and speed. It is envisaged that this new distance-based safety indicator would provide a more realistic depiction of the real traffic situation for safety analysis.

  12. 40 CFR 86.1772-99 - Road load power, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... requirements shall also apply to this subpart: (1) For electric and hybrid electric vehicle lines where it is... VEHICLES AND ENGINES (CONTINUED) General Provisions for the Voluntary National Low Emission Vehicle Program for Light-Duty Vehicles and Light-Duty Trucks § 86.1772-99 Road load power, test weight, and inertia...

  13. 40 CFR 86.129-00 - Road load power, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Road load power, test weight, and inertia weight class determination. 86.129-00 Section 86.129-00 Protection of Environment ENVIRONMENTAL... power, test weight, and inertia weight class determination. (a) * * * 4 For model year 1994 and later...

  14. 40 CFR 86.129-00 - Road load power, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Road load power, test weight, and inertia weight class determination. 86.129-00 Section 86.129-00 Protection of Environment ENVIRONMENTAL... power, test weight, and inertia weight class determination. (a) * * * 4 For model year 1994 and later...

  15. 40 CFR 86.129-00 - Road load power, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Road load power, test weight, and inertia weight class determination. 86.129-00 Section 86.129-00 Protection of Environment ENVIRONMENTAL... power, test weight, and inertia weight class determination. (a) * * * 4 For model year 1994 and later...

  16. 40 CFR 86.229-94 - Road load force, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... inertia weight class determination. 86.229-94 Section 86.229-94 Protection of Environment ENVIRONMENTAL... § 86.229-94 Road load force, test weight, and inertia weight class determination. (a) Flywheels... vehicle weight (pounds) Equivalent test weight (pounds) Inertia weight class (pounds) Up-1,062 1,000 1,000...

  17. 40 CFR 86.129-00 - Road load power, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Road load power, test weight, and inertia weight class determination. 86.129-00 Section 86.129-00 Protection of Environment ENVIRONMENTAL... power, test weight, and inertia weight class determination. (a) * * * 4 For model year 1994 and later...

  18. 40 CFR 86.129-00 - Road load power, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 19 2013-07-01 2013-07-01 false Road load power, test weight, and inertia weight class determination. 86.129-00 Section 86.129-00 Protection of Environment ENVIRONMENTAL... power, test weight, and inertia weight class determination. (a) * * * 4 For model year 1994 and later...

  19. 40 CFR 86.229-94 - Road load force, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... inertia weight class determination. 86.229-94 Section 86.229-94 Protection of Environment ENVIRONMENTAL... § 86.229-94 Road load force, test weight, and inertia weight class determination. (a) Flywheels... vehicle weight (pounds) Equivalent test weight (pounds) Inertia weight class (pounds) Up-1,062 1,000 1,000...

  20. 40 CFR 86.229-94 - Road load force, test weight, and inertia weight class determination.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... inertia weight class determination. 86.229-94 Section 86.229-94 Protection of Environment ENVIRONMENTAL... § 86.229-94 Road load force, test weight, and inertia weight class determination. (a) Flywheels... vehicle weight (pounds) Equivalent test weight (pounds) Inertia weight class (pounds) Up-1,062 1,000 1,000...

  1. Fuzzy chaos control for vehicle lateral dynamics based on active suspension system

    NASA Astrophysics Data System (ADS)

    Huang, Chen; Chen, Long; Jiang, Haobin; Yuan, Chaochun; Xia, Tian

    2014-07-01

    The existing research of the active suspension system (ASS) mainly focuses on the different evaluation indexes and control strategies. Among the different components, the nonlinear characteristics of practical systems and control are usually not considered for vehicle lateral dynamics. But the vehicle model has some shortages on tyre model with side-slip angle, road adhesion coefficient, vertical load and velocity. In this paper, the nonlinear dynamic model of lateral system is considered and also the adaptive neural network of tire is introduced. By nonlinear analysis methods, such as the bifurcation diagram and Lyapunov exponent, it has shown that the lateral dynamics exhibits complicated motions with the forward speed. Then, a fuzzy control method is applied to the lateral system aiming to convert chaos into periodic motion using the linear-state feedback of an available lateral force with changing tire load. Finally, the rapid control prototyping is built to conduct the real vehicle test. By comparison of time response diagram, phase portraits and Lyapunov exponents at different work conditions, the results on step input and S-shaped road indicate that the slip angle and yaw velocity of lateral dynamics enter into stable domain and the results of test are consistent to the simulation and verified the correctness of simulation. And the Lyapunov exponents of the closed-loop system are becoming from positive to negative. This research proposes a fuzzy control method which has sufficient suppress chaotic motions as an effective active suspension system.

  2. Simulated rain events on an urban roadway to understand the dynamics of mercury mobilization in stormwater runoff.

    PubMed

    Eckley, Chris S; Branfireun, Brian

    2009-08-01

    This research focuses on mercury (Hg) mobilization in stormwater runoff from an urban roadway. The objectives were to determine: how the transport of surface-derived Hg changes during an event hydrograph; the influence of antecedent dry days on the runoff Hg load; the relationship between total suspended sediments (TSS) and Hg transport, and; the fate of new Hg input in rain and its relative importance to the runoff Hg load. Simulated rain events were used to control variables to elucidate transport processes and a Hg stable isotope was used to trace the fate of Hg inputs in rain. The results showed that Hg concentrations were highest at the beginning of the hydrograph and were predominantly particulate bound (HgP). On average, almost 50% of the total Hg load was transported during the first minutes of runoff, underscoring the importance of the initial runoff on load calculations. Hg accumulated on the road surface during dry periods resulting in the Hg runoff load increasing with antecedent dry days. The Hg concentrations in runoff were significantly correlated with TSS concentrations (mean r(2)=0.94+/-0.09). The results from the isotope experiments showed that the new Hg inputs quickly become associated with the surface particles and that the majority of Hg in runoff is derived from non-event surface-derived sources.

  3. Effects of the road environment on the development of driver sleepiness in young male drivers.

    PubMed

    Ahlström, Christer; Anund, Anna; Fors, Carina; Åkerstedt, Torbjörn

    2018-03-01

    Latent driver sleepiness may in some cases be masked by for example social interaction, stress and physical activity. This short-term modulation of sleepiness may also result from environmental factors, such as when driving in stimulating environments. The aim of this study is to compare two road environments and investigate how they affect driver sleepiness. Thirty young male drivers participated in a driving simulator experiment where they drove two scenarios: a rural environment with winding roads and low traffic density, and a suburban road with higher traffic density and a more built-up roadside environment. The driving task was essentially the same in both scenarios, i.e. to stay on the road, without much interaction with other road users. A 2 × 2 design, with the conditions rural versus suburban, and daytime (full sleep) versus night-time (sleep deprived), was used. The results show that there were only minor effects of the road environment on subjective and physiological indicators of sleepiness. In contrast, there was an increase in subjective sleepiness, longer blink durations and increased EEG alpha content, both due to time on task and to night-time driving. The two road environments differed both in terms of the demand on driver action and of visual load, and the results indicate that action demand is the more important of the two factors. The notion that driver fatigue should be countered in a more stimulating visual environment such as in the city is thus more likely due to increased task demand rather than to a richer visual scenery. This should be investigated in further studies. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Characterizing heavy metal build-up on urban road surfaces: implication for stormwater reuse.

    PubMed

    Liu, An; Liu, Liang; Li, Dunzhu; Guan, Yuntao

    2015-05-15

    Stormwater reuse is increasingly popular in the worldwide. In terms of urban road stormwater, it commonly contains toxic pollutants such as heavy metals, which could undermine the reuse safety. The research study investigated heavy metal build-up characteristics on urban roads in a typical megacity of South China. The research outcomes show the high variability in heavy metal build-up loads among different urban road sites. The degree of traffic congestion and road surface roughness was found to exert a more significant influence on heavy metal build-up rather than traffic volume. Due to relatively higher heavy metal loads, stormwater from roads with more congested traffic conditions or rougher surfaces might be suitable for low-water-quality required activities while the stormwater from by-pass road sections could be appropriate for relatively high-water-quality required purposes since the stormwater could be relatively less polluted. Based on the research outcomes, a decision-making process for heavy metals based urban road stormwater reuse was proposed. The new finding highlights the importance to undertaking a "fit-for-purpose" road stormwater reuse strategy. Additionally, the research results can also contribute to enhancing stormwater reuse safety. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Low cognitive load and reduced arousal impede practice effects on executive functioning, metacognitive confidence and decision making.

    PubMed

    Jackson, Simon A; Kleitman, Sabina; Aidman, Eugene

    2014-01-01

    The present study investigated the effects of low cognitive workload and the absence of arousal induced via external physical stimulation (motion) on practice-related improvements in executive (inhibitory) control, short-term memory, metacognitive monitoring and decision making. A total of 70 office workers performed low and moderately engaging passenger tasks in two successive 20-minute simulated drives and repeated a battery of decision making and inhibitory control tests three times—before, between and after these drives. For half the participants, visual simulation was synchronised with (moderately arousing) motion generated through LAnd Motion Platform, with vibration levels corresponding to a well-maintained unsealed road. The other half performed the same simulated drive without motion. Participants' performance significantly improved over the three test blocks, which is indicative of typical practice effects. The magnitude of these improvements was the highest when both motion and moderate cognitive load were present. The same effects declined either in the absence of motion (low arousal) or following a low cognitive workload task, thus suggesting two distinct pathways through which practice-related improvements in cognitive performance may be hampered. Practice, however, degraded certain aspects of metacognitive performance, as participants became less likely to detect incorrect decisions in the decision-making test with each subsequent test block. Implications include consideration of low cognitive load and arousal as factors responsible for performance decline and targets for the development of interventions/strategies in low load/arousal conditions such as autonomous vehicle operations and highway driving.

  6. 36 CFR 9.50 - Use of roads by commercial vehicles.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... roadway load limits specified by the Superintendent shall be used on roads administered by the National... 36 Parks, Forests, and Public Property 1 2014-07-01 2014-07-01 false Use of roads by commercial... INTERIOR MINERALS MANAGEMENT Non-Federal Oil and Gas Rights § 9.50 Use of roads by commercial vehicles. (a...

  7. 36 CFR 9.50 - Use of roads by commercial vehicles.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... roadway load limits specified by the Superintendent shall be used on roads administered by the National... 36 Parks, Forests, and Public Property 1 2011-07-01 2011-07-01 false Use of roads by commercial... INTERIOR MINERALS MANAGEMENT Non-Federal Oil and Gas Rights § 9.50 Use of roads by commercial vehicles. (a...

  8. 36 CFR 9.50 - Use of roads by commercial vehicles.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... roadway load limits specified by the Superintendent shall be used on roads administered by the National... 36 Parks, Forests, and Public Property 1 2012-07-01 2012-07-01 false Use of roads by commercial... INTERIOR MINERALS MANAGEMENT Non-Federal Oil and Gas Rights § 9.50 Use of roads by commercial vehicles. (a...

  9. 36 CFR 9.50 - Use of roads by commercial vehicles.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... roadway load limits specified by the Superintendent shall be used on roads administered by the National... 36 Parks, Forests, and Public Property 1 2013-07-01 2013-07-01 false Use of roads by commercial... INTERIOR MINERALS MANAGEMENT Non-Federal Oil and Gas Rights § 9.50 Use of roads by commercial vehicles. (a...

  10. Regression modeling and prediction of road sweeping brush load characteristics from finite element analysis and experimental results.

    PubMed

    Wang, Chong; Sun, Qun; Wahab, Magd Abdel; Zhang, Xingyu; Xu, Limin

    2015-09-01

    Rotary cup brushes mounted on each side of a road sweeper undertake heavy debris removal tasks but the characteristics have not been well known until recently. A Finite Element (FE) model that can analyze brush deformation and predict brush characteristics have been developed to investigate the sweeping efficiency and to assist the controller design. However, the FE model requires large amount of CPU time to simulate each brush design and operating scenario, which may affect its applications in a real-time system. This study develops a mathematical regression model to summarize the FE modeled results. The complex brush load characteristic curves were statistically analyzed to quantify the effects of cross-section, length, mounting angle, displacement and rotational speed etc. The data were then fitted by a multiple variable regression model using the maximum likelihood method. The fitted results showed good agreement with the FE analysis results and experimental results, suggesting that the mathematical regression model may be directly used in a real-time system to predict characteristics of different brushes under varying operating conditions. The methodology may also be used in the design and optimization of rotary brush tools. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Appending High-Resolution Elevation Data to GPS Speed Traces for Vehicle Energy Modeling and Simulation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wood, E.; Burton, E.; Duran, A.

    Accurate and reliable global positioning system (GPS)-based vehicle use data are highly valuable for many transportation, analysis, and automotive considerations. Model-based design, real-world fuel economy analysis, and the growing field of autonomous and connected technologies (including predictive powertrain control and self-driving cars) all have a vested interest in high-fidelity estimation of powertrain loads and vehicle usage profiles. Unfortunately, road grade can be a difficult property to extract from GPS data with consistency. In this report, we present a methodology for appending high-resolution elevation data to GPS speed traces via a static digital elevation model. Anomalous data points in the digitalmore » elevation model are addressed during a filtration/smoothing routine, resulting in an elevation profile that can be used to calculate road grade. This process is evaluated against a large, commercially available height/slope dataset from the Navteq/Nokia/HERE Advanced Driver Assistance Systems product. Results will show good agreement with the Advanced Driver Assistance Systems data in the ability to estimate road grade between any two consecutive points in the contiguous United States.« less

  12. Disturbance observer based Takagi-Sugeno fuzzy control for an active seat suspension

    NASA Astrophysics Data System (ADS)

    Ning, Donghong; Sun, Shuaishuai; Zhang, Fei; Du, Haiping; Li, Weihua; Zhang, Bangji

    2017-09-01

    In this paper, a disturbance observer based Takagi-Sugeno (TS) fuzzy controller is proposed for an active seat suspension; both simulations and experiments have been performed verifying the performance enhancement and stability of the proposed controller. The controller incorporates closed-loop feedback control using the measured acceleration of the seat and deflection of the suspension; these two variables can be easily measured in practical applications, thus allowing the proposed controller to be robust and adaptable. A disturbance observer that can estimate the disturbance caused by friction, model simplification, and controller output error has also been used to compensate a H∞ state feedback controller. The TS fuzzy control method is applied to enhance the controller's performance by considering the variation of driver's weight during operation. The vibration of a heavy duty vehicle seat is largest in the frequency range between 2 Hz and 4 Hz, in the vertical direction; therefore, it is reasonable to focus on controlling low frequency vibration amplitudes and maintain the seat suspensions passivity at high frequency. Moreover, both the simulation and experimental results show that the active seat suspension with the proposed controller can effectively isolate unwanted vibration amplitudes below 4.5 Hz, when compared with a well-tuned passive seat suspension. The active controller has been further validated under bump and random road tests with both a 55 kg and a 70 kg loads. The bump road test demonstrated the controller has good transient response capabilities. The random road test result has been presented both in the time domain and the frequency domain. When with the above two loads, the controlled seat suspensions root-mean-square (RMS) accelerations were reduced by 45.5% and 49.5%, respectively, compared with a well-tuned passive seat suspension. The proposed active seat suspension controller has great potential and is very practical for application as it can significantly improve heavy duty driver's ride comfort.

  13. Meso-scopic Densification in Brittle Granular Materials

    NASA Astrophysics Data System (ADS)

    Neal, William; Appleby-Thomas, Gareth; Collins, Gareth

    2013-06-01

    Particulate materials are ideally suited to shock absorbing applications due to the large amounts of energy required to deform their inherently complex meso-structure. Significant effort is being made to improve macro-scale material models to represent these atypical materials. On the long road towards achieving this capability, an important milestone would be to understand how particle densification mechanisms are affected by loading rate. In brittle particulate materials, the majority of densification is caused by particle fracture. Macro-scale quasi-static and dynamic compaction curves have been measured that show good qualitative agreement. There are, however, some differences that appear to be dependent on the loading rate that require further investigation. This study aims to investigate the difference in grain-fracture behavior between the quasi-static and shock loading response of brittle glass microsphere beds using a combination of quasi-static and dynamic loading techniques. Results from pressure-density measurements, sample recovery, and meso-scale hydrocode models (iSALE, an in-house simulation package) are discussed to explain the differences in particle densification mechanisms between the two loading rate regimes. Gratefully funded by AWE.plc.

  14. Transition to manual: Comparing simulator with on-road control transitions.

    PubMed

    Eriksson, A; Banks, V A; Stanton, N A

    2017-05-01

    Whilst previous research has explored how driver behaviour in simulators may transfer to the open road, there has been relatively little research showing the same transfer within the field of driving automation. As a consequence, most research into human-automation interaction has primarily been carried out in a research laboratory or on closed-circuit test tracks. The aim of this study was to assess whether research into non-critical control transactions in highly automated vehicles performed in driving simulators correlate with road driving conditions. Twenty six drivers drove a highway scenario using an automated driving mode in the simulator and twelve drivers drove on a public motorway in a Tesla Model S with the Autopilot activated. Drivers were asked to relinquish, or resume control from the automation when prompted by the vehicle interface in both the simulator and on road condition. Drivers were generally faster to resume control in the on-road driving condition. However, strong positive correlations were found between the simulator and on road driving conditions for drivers transferring control to and from automation. No significant differences were found with regard to workload, perceived usefulness and satisfaction between the simulator and on-road drives. The results indicate high levels of relative validity of driving simulators as a research tool for automated driving research. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Analytical approach to determine vertical dynamics of a semi-trailer truck from the point of view of goods protection

    NASA Astrophysics Data System (ADS)

    Pidl, Renáta

    2018-01-01

    The overwhelming majority of intercontinental long-haul transportations of goods are usually carried out on road by semi-trailer trucks. Vibration has a major effect regarding the safety of the transport, the load and the transported goods. This paper deals with the logistics goals from the point of view of vibration and summarizes the methods to predict or measure the vibration load in order to design a proper system. From these methods, the focus of this paper is on the computer simulation of the vibration. An analytical method is presented to calculate the vertical dynamics of a semi-trailer truck containing general viscous damping and exposed to harmonic base excitation. For the purpose of a better understanding, the method will be presented through a simplified four degrees-of-freedom (DOF) half-vehicle model, which neglects the stiffness and damping of the tires, thus the four degrees-of-freedom are the vertical and angular displacements of the truck and the trailer. From the vertical and angular accelerations of the trailer, the vertical acceleration of each point of the platform of the trailer can easily be determined, from which the forces acting on the transported goods are given. As a result of this paper the response of the full platform-load-packaging system to any kind of vehicle, any kind of load and any kind of road condition can be analyzed. The peak acceleration of any point on the platform can be determined by the presented analytical method.

  16. Design of Large Stone Asphalt Mixes for Low-Volume Roads Using Six-Inch Diameter Marshall Specimens

    DOT National Transportation Integrated Search

    1991-01-01

    Premature rutting of road pavements constructed for hauling coal and logs is common. Although these roads carry low volumes of traffic, they are subjected to heavy and channelized wheel loads. Unfortunately, conventional asphalt mixes containing aggr...

  17. Load rating of complex bridges.

    DOT National Transportation Integrated Search

    2010-07-01

    The National Bridge Inspection Standards require highway departments to inspect, evaluate, and determine load ratings for : structures defined as bridges located on all public roads. Load rating of bridges is performed to determine the live load that...

  18. Modelling heavy metals build-up on urban road surfaces for effective stormwater reuse strategy implementation.

    PubMed

    Hong, Nian; Zhu, Panfeng; Liu, An

    2017-12-01

    Urban road stormwater is an alternative water resource to mitigate water shortage issues in the worldwide. Heavy metals deposited (build-up) on urban road surface can enter road stormwater runoff, undermining stormwater reuse safety. As heavy metal build-up loads perform high variabilities in terms of spatial distribution and is strongly influenced by surrounding land uses, it is essential to develop an approach to identify hot-spots where stormwater runoff could include high heavy metal concentrations and hence cannot be reused if it is not properly treated. This study developed a robust modelling approach to estimating heavy metal build-up loads on urban roads using land use fractions (representing percentages of land uses within a given area) by an artificial neural network (ANN) model technique. Based on the modelling results, a series of heavy metal load spatial distribution maps and a comprehensive ecological risk map were generated. These maps provided a visualization platform to identify priority areas where the stormwater can be safely reused. Additionally, these maps can be utilized as an urban land use planning tool in the context of effective stormwater reuse strategy implementation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Integrated control of lateral and vertical vehicle dynamics based on multi-agent system

    NASA Astrophysics Data System (ADS)

    Huang, Chen; Chen, Long; Yun, Chaochun; Jiang, Haobin; Chen, Yuexia

    2014-03-01

    The existing research of the integrated chassis control mainly focuses on the different evaluation indexes and control strategy. Among the different evaluation indexes, the comprehensive properties are usually not considered based on the non-linear superposition principle. But, the control strategy has some shortages on tyre model with side-slip angle, road adhesion coefficient, vertical load and velocity. In this paper, based on belief, desire and intention(BDI)-agent model framework, the TYRE agent, electric power steering(EPS) agent and active suspension system(ASS) agent are proposed. In the system(SYS) agent, the coordination mechanism is employed to manage interdependences and conflicts among other agents, so as to improve the flexibility, adaptability, and robustness of the global control system. Due to the existence of the simulation demand of dynamic performance, the vehicle multi-body dynamics model is established by SIMPACK. And then the co-simulation analysis is conducted to evaluate the proposed multi-agent system(MAS) controller. The simulation results demonstrate that the MAS has good effect on the performance of EPS and ASS. Meantime, the better road feeling for the driver is provided considering the multiple and complex driving traffic. Finally, the MAS rapid control prototyping is built to conduct the real vehicle test. The test results are consistent to the simulation results, which verifies the correctness of simulation. The proposed research ensures the driving safety, enhances the handling stability, and improves the ride comfort.

  20. Development of Anti-lock Braking System (ABS) for Vehicles Braking

    NASA Astrophysics Data System (ADS)

    Minh, Vu Trieu; Oamen, Godwin; Vassiljeva, Kristina; Teder, Leo

    2016-11-01

    This paper develops a real laboratory of anti-lock braking system (ABS) for vehicle and conducts real experiments to verify the ability of this ABS to prevent the vehicle wheel from being locked while braking. Two controllers of PID and fuzzy logic are tested for analysis and comparison. This ABS laboratory is designed for bachelor and master students to simulate and analyze performances of ABS with different control techniques on various roads and load conditions. This paper provides educational theories and practices on the design of control for system dynamics.

  1. Moisture Content Numerical Simulation on Structural Damage of Hot Mix Asphaltic Pavement

    NASA Astrophysics Data System (ADS)

    Abejide, O. S.; Mostafa, M. M. H.

    2017-06-01

    Considering the merits of road transportation in the economy and communication activities of the modern societies, it is imperative to design a safe, stable, efficient and cost effective road that will lead to increased economic development and growth of the South African nation. Although, the overarching effect of failed roads has in many ways led to increased travel time, loss of life and property; leading to reduced driver control on failed road sections (riding quality). Thus, time rate delamination of flexible pavement is a major focus of this study. Since structural collapse in a flexible pavement structure is caused by the evolution of different types of damage mechanisms; fatigue cracking, advanced crushing, temperature variation, and delamination. The effect of moisture content on HMA was analysed. The analysis from the multi-layered elastic model indicates that increase in moisture content in the underlying layer of HMA pavement results to increase in the strain of the individual layers and culminates to a decrease in the structural carrying capacity of the pavement with respect to number of load cycles that can be carried on the HMA pavement. This study shows a clear relationship between the moisture/saturation coefficient and the Elastic Modulus of the underlying geometric material layer properties of the pavement during the service life of the pavement.

  2. The impact of self-driving cars on existing transportation networks

    NASA Astrophysics Data System (ADS)

    Ji, Xiang

    2018-04-01

    In this paper, considering the usage of self-driving, I research the congestion problems of traffic networks from both macro and micro levels. Firstly, the macroscopic mathematical model is established using the Greenshields function, analytic hierarchy process and Monte Carlo simulation, where the congestion level is divided into five levels according to the average vehicle speed. The roads with an obvious congestion situation is investigated mainly and the traffic flow and topology of the roads are analyzed firstly. By processing the data, I propose a traffic congestion model. In the model, I assume that half of the non-self-driving cars only take the shortest route and the other half can choose the path randomly. While self-driving cars can obtain vehicle density data of each road and choose the path more reasonable. When the path traffic density exceeds specific value, it cannot be selected. To overcome the dimensional differences of data, I rate the paths by BORDA sorting. The Monte Carlo simulation of Cellular Automaton is used to obtain the negative feedback information of the density of the traffic network, where the vehicles are added into the road network one by one. I then analyze the influence of negative feedback information on path selection of intelligent cars. The conclusion is that the increase of the proportion of intelligent vehicles will make the road load more balanced, and the self-driving cars can avoid the peak and reduce the degree of road congestion. Combined with other models, the optimal self-driving ratio is about sixty-two percent. From the microscopic aspect, by using the single-lane traffic NS rule, another model is established to analyze the road Partition scheme. The self-driving traffic is more intelligent, and their cooperation can reduce the random deceleration probability. By the model, I get the different self-driving ratio of space-time distribution. I also simulate the case of making a lane separately for self-driving, compared to the former model. It is concluded that a single lane is more efficient in a certain interval. However, it is not recommended to offer a lane separately. However, the self-driving also faces the problem of hacker attacks and greater damage after fault. So, when self-driving ratio is higher than a certain value, the increase of traffic flow rate is small. In this article, that value is discussed, and the optimal proportion is determined. Finally, I give a nontechnical explanation of the problem.

  3. Road dust correlated with decreased reproduction of the endangered Utah shrub Hesperidanthus suffrutescens

    USDA-ARS?s Scientific Manuscript database

    Roads associated with energy development have fragmented much of the Colorado Plateau and elsewhere. Beyond reducing available habitat, spreading exotic species, and creating barriers to dispersal, unpaved roads also increase dust loads on plants and potentially disrupt pollinate behavior, which may...

  4. Modeling salinization and recovery of road salt-impacted lakes in temperate regions based on long-term monitoring of Lake George, New York (USA) and its drainage basin.

    PubMed

    Sutherland, J W; Norton, S A; Short, J W; Navitsky, C

    2018-05-08

    Road salt mitigates winter highway icing but accumulates in watershed soils and receiving waters, affecting soil chemistry and physical, biological, and ecological processes. Despite efforts to reduce salt loading in watersheds, accumulated cations and Cl - continue to impact tributaries and lakes, and the recovery process is not well understood. Lake George, New York (USA) is typical of many temperate lakes at risk for elevated Cl - concentrations from winter deicing; the lake salt concentration increased by ~3.4% year -1 since 1980. Here, we evaluated the ionic composition in Finkle Brook, a major watershed draining to Lake George, studied intermittently since 1970 and typical of other salt-impacted Lake George tributaries. Salt loading in the Lake George basin since the 1940s displaced cations from exchange sites in basin soils; these desorbed cations follow a simple ion-exchange model, with lower sodium and higher calcium, magnesium and potassium fluxes in runoff. Reduced salt application in the Finkle Brook watershed during the low-snow winter of 2015-2016 led to a 30-40% decline of Cl - and base cations in the tributary, implying a Cl - soil half-life of 1-2 years. We developed a conceptual model that describes cation behavior in runoff from a watershed that received road salt loading over a long period of time, and then recovery following reduced salt loading. Next, we developed a dynamic model estimating time to steady-state for Cl - in Lake George with road salt loading starting in 1940, calibrating the model with tributary runoff and lake chemistry data from 1970 and 1980, respectively, and forecasting Cl - concentrations in Lake George based on various scenarios of salt loading and soil retention of Cl - . Our Lake George models are readily adaptable to other temperate lakes with drainage basins where road salt is applied during freezing conditions and paved roads cover a portion of the watershed. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Fabrication and Analysis Signal Optical Fiber Sensor Based On Bend Loss for Weight in Motion Applications

    NASA Astrophysics Data System (ADS)

    Aftah Syukron, Ahmad; Marzuki, Ahmad; Setyawan, Ary

    2017-11-01

    Road network plays very important role in economic development. Overweight is one of the main factors contributing to road damage. To minimize this factor, road authority has to make sure that all vehicles operate in according to maximum vehicle regulation set by the government. The one solution can use from this problem is Weight in motion (WIM) technology. WIM technology allows measuring vehicle weight quickly. The sensor is one of the important components in the WIM system. This paper presents a model of WIM fiber sensor work based on bend loss. Fiber sensor has made by coiling optical fiber. Coiling optical fiber has managed in the elliptical shape rubber coil. Rubber coil then is planted in the pad of sensor. The principle of this sensor is a detecting of the shift light intensity output of optical fiber when the vehicles a passing through on fiber sensor. Loading was carried out using loaded truck model. Data was carried out with variations of load and load positions in the truck. The results can be concluded that the shift light intensity is greater with the more shift loads. The loader of the truck has also resulted in the greater loss. Loads in the truck distributed on the axles due to the position of loads.

  6. Environmental exposure of road borders to zinc.

    PubMed

    Blok, J

    2005-09-15

    The emissions of zinc along roads originating from tyre wear, corrosion of safety fence and other traffic-related sources have been quantified and validated by measured long-term loads in road run-off and airborne solids (drift) for 29 published case studies. The distribution pattern over the road border at various distances from the edge of the paved surface is assessed on the basis of 38 published case studies with measured concentrations in soil. For the impact assessment, the road border is differentiated into a zone that is part of the "technosphere" and the "target zone" beyond that technosphere that can be considered as part of the receiving environment. The "technosphere" of the road includes the central reservation, the hard and the soft shoulder or, if one or both shoulders are not present, the so-called obstacle "free zone" that is defined by road engineers. Pollution within the technosphere may require appropriate management of solid disposal and isolation from groundwater to prevent further distribution of pollutants to the environment. In the target zone along regional roads, the zinc load is about 4 mg/m(2) year and this is of the same order of magnitude as that of atmospheric deposition in areas beyond the influence of roads (background). In the target zone along highways, the zinc load is increased in comparison to the background deposition. The average load of about 38 mg/m(2) year is similar to that in fertilised agricultural land. Because most of the emitted zinc stays in the technosphere, the total amount entering this target zone along highways is limited. From the 140 tons of zinc per year that is released from tyre wear in The Netherlands, 64 tons is emitted in the urban area, 6.5 tons reaches to the target zones of all roads and only 1.1 tons of zinc will enter the target zone along highways. This amount will be further decreased by the application of porous asphalt in the near future. The emission from safety fence corrosion does not enter the target zone. Only in special cases, such as bridges, crossings and squares the release of zinc from these sources may enter the aquatic environment by the discharge of run-off.

  7. Examining Road Traffic Mortality Status in China: A Simulation Study

    PubMed Central

    Schwebel, David C.; Li, Li; Hu, Guoqing

    2016-01-01

    Background Data from the Chinese police service suggest substantial reductions in road traffic injuries since 2002, but critics have questioned the accuracy of those data, especially considering conflicting data reported by the health department. Methods To address the gap between police and health department data and to determine which may be more accurate, we conducted a simulation study based on the modified Smeed equation, which delineates a non-linear relation between road traffic mortality and the level of motorization in a country or region. Our goal was to simulate trends in road traffic mortality in China and compare performances in road traffic safety management between China and 13 other countries. Results Chinese police data indicate a peak in road traffic mortalities in 2002 and a significant and a gradual decrease in population-based road traffic mortality since 2002. Health department data show the road traffic mortality peaked in 2012. In addition, police data suggest China’s road traffic mortality peaked at a much lower motorization level (0.061 motor vehicles per person) in 2002, followed by a reduction in mortality to a level comparable to that of developed countries. Simulation results based on health department data suggest high road traffic mortality, with a mortality peak in 2012 at a moderate motorization level (0.174 motor vehicles per person). Comparisons to the other 13 countries suggest the health data from China may be more valid than the police data. Conclusion Our simulation data indicate China is still at a stage of high road traffic mortality, as suggested by health data, rather than a stage of low road traffic mortality, as suggested by police data. More efforts are needed to integrate safety into road design, improve road traffic management, improve data quality, and alter unsafe behaviors of pedestrians, drivers and passengers in China. PMID:27071008

  8. Assessing the Magnitude of Polycyclic Aromatic Hydrocarbon Loading from Road Surfaces and Its Effect on Algal Productivity

    DOT National Transportation Integrated Search

    2010-06-01

    The hypotheses of the study were that PAHs washing off roads would retard the growth of aquatic life-supporting algae and promote the growth of harmful, toxin-producing algae in estuaries, such as the Chesapeake Bay. Runoff from various road surfaces...

  9. 38 CFR 39.61 - Site planning standards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... roads shall be generally 24 feet wide. (4) Pavement design. The pavement section of all roads, service areas, and parking areas shall be designed for the maximum anticipated traffic loads and existing soil conditions and in accordance with local and State design criteria. (5) Curbs. Bituminous roads may be...

  10. 38 CFR 39.61 - Site planning standards.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... roads shall be generally 24 feet wide. (4) Pavement design. The pavement section of all roads, service areas, and parking areas shall be designed for the maximum anticipated traffic loads and existing soil conditions and in accordance with local and State design criteria. (5) Curbs. Bituminous roads may be...

  11. 38 CFR 39.61 - Site planning standards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... roads shall be generally 24 feet wide. (4) Pavement design. The pavement section of all roads, service areas, and parking areas shall be designed for the maximum anticipated traffic loads and existing soil conditions and in accordance with local and State design criteria. (5) Curbs. Bituminous roads may be...

  12. 38 CFR 39.61 - Site planning standards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... roads shall be generally 24 feet wide. (4) Pavement design. The pavement section of all roads, service areas, and parking areas shall be designed for the maximum anticipated traffic loads and existing soil conditions and in accordance with local and State design criteria. (5) Curbs. Bituminous roads may be...

  13. 36 CFR 7.7 - Rocky Mountain National Park.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... permit for trucking on a park road when the load carried originates and terminates within the counties of Larimer, Boulder, or Grand, Colorado. (2) The fee charged for such trucking over Trail Ridge Road is the... established roads or parking areas, and are permitted within established campgrounds and picnic areas; dogs...

  14. 36 CFR 7.7 - Rocky Mountain National Park.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... permit for trucking on a park road when the load carried originates and terminates within the counties of Larimer, Boulder, or Grand, Colorado. (2) The fee charged for such trucking over Trail Ridge Road is the... established roads or parking areas, and are permitted within established campgrounds and picnic areas; dogs...

  15. 36 CFR 7.7 - Rocky Mountain National Park.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... permit for trucking on a park road when the load carried originates and terminates within the counties of Larimer, Boulder, or Grand, Colorado. (2) The fee charged for such trucking over Trail Ridge Road is the... established roads or parking areas, and are permitted within established campgrounds and picnic areas; dogs...

  16. Field investigation of low-temperature cracking and stiffness moduli on selected roads with conventional and high modulus asphalt concrete

    NASA Astrophysics Data System (ADS)

    Judycki, Józef; Jaczewski, Mariusz; Ryś, Dawid; Pszczoła, Marek; Jaskuła, Piotr; Glinicki, Adam

    2017-09-01

    High Modulus Asphalt Concrete (HMAC) was introduced in Poland as a one of the solutions to the problem of rutting, type of deterioration common in the 1990s. After first encouraging trials in 2002 HMAC was widely used for heavily loaded national roads and motorways. However some concerns were raised about low-temperature cracking of HMAC. This was the main reason of the studies presented in this article were started. The article presents the comparison of performance of pavements constructed in typical contract conditions with the road bases made of HMAC and conventional asphalt concrete (AC). The field investigation was focused on the number of low-temperature cracks, bearing capacity (based on FWD test) of road sections localized in coldest region of Poland. Also load transfer efficiency of selected low-temperature cracks was assessed. FWD test confirmed lower deflections of pavements with HMAC and two times higher stiffness modulus of asphalt courses in comparison to pavements constructed with conventional AC mixtures. Relation of stiffness of asphalt layers and amount of low-temperature cracks showed that the higher stiffness modulus of asphalt layers could lead to increase of the number of low-temperature cracks. FWD test results showed that the load transfer efficiency of low-temperature cracks on pavements with HMAC presents very low values, very close to lack of load transfer. It was surprising as section with HMAC road base were aged from 2 to 5 years and presented very good bearing capacity.

  17. Where Does Road Salt Go - a Static Salt Model

    NASA Astrophysics Data System (ADS)

    Yu, C. W.; Liu, F.; Moriarty, V. W.

    2017-12-01

    Each winter, more than 15 million tons of road salt is applied in the United States for the de-icing purpose. Considerable amount of chloride in road salt flows into streams/drainage systems with the snow melt runoff and spring storms, and eventually goes into ecologically sensitive low-lying areas in the watershed, such as ponds and lakes. In many watersheds in the northern part of US, the chloride level in the water body has increased significantly in the past decades, and continues an upward trend. The environmental and ecological impact of the elevated chloride level can no longer be ignored. However although there are many studies on the biological impact of elevated chloride levels, there are few investigations on how the spatially distributed road salt application affects various parts of the watershed. In this presentation, we propose a static road salt model as a first-order metric to address spacial distribution of salt loading. Derived from the Topological Wetness Index (TWI) in many hydrological models, this static salt model provides a spatial impact as- sessment of road salt applications. To demonstrate the effectiveness of the static model, National Elevation Dataset (NED) of ten-meter resolution of Lake George watershed in New York State is used to generate the TWI, which is used to compute a spatially dis- tributed "salt-loading coefficient" of the whole watershed. Spatially varying salt applica- tion rate is then aggregated, using the salt-loading coefficients as weights, to provide salt loading assessments of streams in the watershed. Time-aggregated data from five CTD (conductivity-temperature-depth) sensors in selected streams are used for calibration. The model outputs and the sensor data demonstrate a strong linear correlation, with the R value of 0.97. The investigation shows that the static modeling approach may provide an effective method for the understanding the input and transport of road salt to within watersheds.

  18. Effects of land-use changes and stormflow-detention basins on flooding and nonpoint-source pollution, in Irondequoit Creek basin, Monroe and Ontario counties, New York--application of a precipitation-runoff model

    USGS Publications Warehouse

    Coon, William F.; Johnson, Mark S.

    2005-01-01

    Urbanization of the 150-square-mile Irondequoit Creek basin in Monroe and Ontario Counties, N.Y., continues to spread southward and eastward from the City of Rochester, on the shore of Lake Ontario. Conversion of forested land to other uses over the past 40 years has increased to the extent that more than 50 percent of the basin is now developed. This expansion has increased flooding and impaired stream-water quality in the northern (downstream) half of the basin. A precipitation-runoff model of the Irondequoit Creek basin was developed with the model code HSPF (Hydrological Simulation Program--FORTRAN) to simulate the effects of land-use changes and stormflow-detention basins on flooding and nonpoint-source pollution on the basin. Model performance was evaluated through a combination of graphical comparisons and statistical tests, and indicated 'very good' agreement (mean error less than 10 percent) between observed and simulated daily and monthly streamflows, between observed and simulated monthly water temperatures, and between observed total suspended solids loads and simulated sediment loads. Agreement between monthly observed and simulated nutrient loads was 'very good' (mean error less than 15 percent) or 'good' (mean error between 15 and 25 percent). Results of model simulations indicated that peak flows and loads of sediment and total phosphorus would increase in a rural subbasin, where 10 percent of the basin was converted from forest and grassland to pervious and impervious developed areas. Subsequent simulation of a stormflow-detention basin at the mouth of this subbasin indicated that peak flows and constituent loads would decrease below those that were generated by the land-use-change scenario, and, in some cases, below those that were simulated by the original land-use scenario. Other results from model simulations of peak flows over a 30-year period (1970-2000), with and without simulation of 50-percent flow reductions at one existing and nine hypothetical stormflow-detention basins, indicated that stormflow-detention basins would likely decrease peak flows 14 to 17 percent on Allen Creek and 17 to 18 percent on Irondequoit Creek at Blossom Road. The model is intended as a management tool that water-resource managers can use to guide decisions regarding future development in the basin. The model and associated files are designed to permit (1) creation of scenarios that represent planned or hypothetical development in the basin, and (2) assessment of the flooding and chemical loads that are likely to result. Instream stormflow-detention basins can be simulated in separate scenarios to assess their effect on flooding and chemical loads. This report (1) provides examples of how the model can be applied to address these issues, (2) discusses the model revisions required to simulate land-use changes and detention basins, and (3) describes the analytical steps necessary to evaluate the model results.

  19. Assessment of thermal load on transported goats administered with ascorbic acid during the hot-dry conditions

    NASA Astrophysics Data System (ADS)

    Minka, N. S.; Ayo, J. O.

    2012-03-01

    The major factor in the induction of physiological stress during road transportation of livestock is the complex fluctuations of the thermal transport microenvironment, encountered when animals are transported across different ecological zones. Recommended guidelines on optimum "on-board" conditions in which goats should be transported are lacking, and there are no acceptable ranges and limits for the thermal loads to which goats may be subjected during long-distance road transportation in hot-dry conditions. Panting score (PS), rectal temperature (RT), heart rate (HR) and respiratory rate (RR) were employed as reliable stress indices to assess the effects of different thermal loads, measured as temperature humidity index (THI), encountered in the vehicle during 12 h of road transportation of 40 goats, and to suggest the administration of 100 mg/kg body weight of ascorbic acid (AA) as an ameliorating agent. The results obtained showed that the PS, RT, HR and RR rose above normal reference values with increase in the THI and journey duration. The rise in PS value, which is a visual indicator of the severity of thermal load, was the most pronounced. The results suggest that values of THI in the vehicle up to 94.6 constitute no risk, while at of 100 it presents a moderate risk and above 100 may result in severe stress. The relationships between the thermal load and the physiological variables were positive and significant ( P < 0.05). They reflect the degree of stress imposed by each THI value during the transportation, and may be used as recommended ranges and limit thermal load values in transported goats. The results demonstrated that administration of 100 mg/kg body weight of AA before road transportation mitigated the risk of adverse effects of high THI values and other stress factors due to road transportation in goats.

  20. Transforming GIS data into functional road models for large-scale traffic simulation.

    PubMed

    Wilkie, David; Sewall, Jason; Lin, Ming C

    2012-06-01

    There exists a vast amount of geographic information system (GIS) data that model road networks around the world as polylines with attributes. In this form, the data are insufficient for applications such as simulation and 3D visualization-tools which will grow in power and demand as sensor data become more pervasive and as governments try to optimize their existing physical infrastructure. In this paper, we propose an efficient method for enhancing a road map from a GIS database to create a geometrically and topologically consistent 3D model to be used in real-time traffic simulation, interactive visualization of virtual worlds, and autonomous vehicle navigation. The resulting representation provides important road features for traffic simulations, including ramps, highways, overpasses, legal merge zones, and intersections with arbitrary states, and it is independent of the simulation methodologies. We test the 3D models of road networks generated by our algorithm on real-time traffic simulation using both macroscopic and microscopic techniques.

  1. Influence of low impact development construction on pollutant process of road-deposited sediments and associated heavy metals.

    PubMed

    Ma, Yukun; Gong, Manli; Zhao, Hongtao; Li, Xuyong

    2018-02-01

    Intense Low-Impact Development (LID) construction in China could lead to increasingly severe stormwater and receiving water pollution due to the lack of appropriate regulation for mitigating pollution from LID construction. Samples of road-deposited sediments (RDS) were collected from 50 study sites at seven LID construction stages and four road hierarchies to analyze the pollution process and determine the size of the region influenced by LID construction. Six heavy metals were analyzed, and the RDS index model was adopted to estimate the potential heavy metal load washed off by stormwater runoff. Analysis of variance revealed that the excavation and gravel filling of rain gardens and excavation of porous pavements were critical LID construction stages that contributed the largest masses of RDS per unit area to road surfaces. Although the concentration of heavy metals at LID construction sites was lower than at sites without LID construction, the load of heavy metals washed off from LID construction was much higher. In addition, the sizes of regions influenced by accumulated RDS from LID construction descended in the following order: arterial road (600-775m)>collector road (150-200m)>access road (100-150m)>laneway (20-30m). According to the characteristics of LID construction at the study sites, the potential total solid loads in stormwater throughout China were estimated to reach 36,694t by 2020 and 146,777t by 2030. According to the results of analysis, several recommendations are provided for designing LID construction regulations to mitigate stormwater pollution. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Low Cognitive Load and Reduced Arousal Impede Practice Effects on Executive Functioning, Metacognitive Confidence and Decision Making

    PubMed Central

    Jackson, Simon A.; Kleitman, Sabina; Aidman, Eugene

    2014-01-01

    The present study investigated the effects of low cognitive workload and the absence of arousal induced via external physical stimulation (motion) on practice-related improvements in executive (inhibitory) control, short-term memory, metacognitive monitoring and decision making. A total of 70 office workers performed low and moderately engaging passenger tasks in two successive 20-minute simulated drives and repeated a battery of decision making and inhibitory control tests three times – before, between and after these drives. For half the participants, visual simulation was synchronised with (moderately arousing) motion generated through LAnd Motion Platform, with vibration levels corresponding to a well-maintained unsealed road. The other half performed the same simulated drive without motion. Participants’ performance significantly improved over the three test blocks, which is indicative of typical practice effects. The magnitude of these improvements was the highest when both motion and moderate cognitive load were present. The same effects declined either in the absence of motion (low arousal) or following a low cognitive workload task, thus suggesting two distinct pathways through which practice-related improvements in cognitive performance may be hampered. Practice, however, degraded certain aspects of metacognitive performance, as participants became less likely to detect incorrect decisions in the decision-making test with each subsequent test block. Implications include consideration of low cognitive load and arousal as factors responsible for performance decline and targets for the development of interventions/strategies in low load/arousal conditions such as autonomous vehicle operations and highway driving. PMID:25549327

  3. Simulation of Surface Erosion on a Logging Road in the Jackson Demonstration State Forest

    Treesearch

    Teresa Ish; David Tomberlin

    2007-01-01

    In constructing management models for the control of sediment delivery to streams, we have used a simulation model of road surface erosion known as the Watershed Erosion Prediction Project (WEPP) model, developed by the USDA Forest Service. This model predicts discharge, erosion, and sediment delivery at the road segment level, based on a stochastic climate simulator...

  4. Effects of logging road removal on suspended sediment loads and turbidity

    Treesearch

    Randy D. Klein; Vicki Ozaki

    2017-01-01

    Poorly designed and unmaintained logging roads pose serious risks to aquatic ecosystems through sediment delivery from stream crossing failures and landslides. Redwood National Park (RNP) in northern coastal California has been implementing a restoration program for almost four decades, focused primarily on removing (decommissioning) abandoned logging roads on former...

  5. Comparison of a Virtual Older Driver Assessment with an On-Road Driving Test.

    PubMed

    Eramudugolla, Ranmalee; Price, Jasmine; Chopra, Sidhant; Li, Xiaolan; Anstey, Kaarin J

    2016-12-01

    To design a low-cost simulator-based driving assessment for older adults and to compare its validity with that of an on-road driving assessment and other measures of older driver risk. Cross-sectional observational study. Canberra, Australia. Older adult drivers (N = 47; aged 65-88, mean age 75.2). Error rate on a simulated drive with environment and scoring procedure matched to those of an on-road test. Other measures included participant age, simulator sickness severity, neuropsychological measures, and driver screening measures. Outcome variables included occupational therapist (OT)-rated on-road errors, on-road safety rating, and safety category. Participants' error rate on the simulated drive was significantly correlated with their OT-rated driving safety (correlation coefficient (r) = -0.398, P = .006), even after adjustment for age and simulator sickness (P = .009). The simulator error rate was a significant predictor of categorization as unsafe on the road (P = .02, sensitivity 69.2%, specificity 100%), with 13 (27%) drivers assessed as unsafe. Simulator error was also associated with other older driver safety screening measures such as useful field of view (r = 0.341, P = .02), DriveSafe (r = -0.455, P < .01), and visual motion sensitivity (r = 0.368, P = .01) but was not associated with memory (delayed word recall) or global cognition (Mini-Mental State Examination). Drivers made twice as many errors on the simulated assessment as during the on-road assessment (P < .001), with significant differences in the rate and type of errors between the two mediums. A low-cost simulator-based assessment is valid as a screening instrument for identifying at-risk older drivers but not as an alternative to on-road evaluation when accurate data on competence or pattern of impairment is required for licensing decisions and training programs. © 2016, Copyright the Authors Journal compilation © 2016, The American Geriatrics Society.

  6. High-Fidelity Roadway Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Wang, Jie; Papelis, Yiannis; Shen, Yuzhong; Unal, Ozhan; Cetin, Mecit

    2010-01-01

    Roads are an essential feature in our daily lives. With the advances in computing technologies, 2D and 3D road models are employed in many applications, such as computer games and virtual environments. Traditional road models were generated by professional artists manually using modeling software tools such as Maya and 3ds Max. This approach requires both highly specialized and sophisticated skills and massive manual labor. Automatic road generation based on procedural modeling can create road models using specially designed computer algorithms or procedures, reducing the tedious manual editing needed for road modeling dramatically. But most existing procedural modeling methods for road generation put emphasis on the visual effects of the generated roads, not the geometrical and architectural fidelity. This limitation seriously restricts the applicability of the generated road models. To address this problem, this paper proposes a high-fidelity roadway generation method that takes into account road design principles practiced by civil engineering professionals, and as a result, the generated roads can support not only general applications such as games and simulations in which roads are used as 3D assets, but also demanding civil engineering applications, which requires accurate geometrical models of roads. The inputs to the proposed method include road specifications, civil engineering road design rules, terrain information, and surrounding environment. Then the proposed method generates in real time 3D roads that have both high visual and geometrical fidelities. This paper discusses in details the procedures that convert 2D roads specified in shape files into 3D roads and civil engineering road design principles. The proposed method can be used in many applications that have stringent requirements on high precision 3D models, such as driving simulations and road design prototyping. Preliminary results demonstrate the effectiveness of the proposed method.

  7. Research of biofuels on performance, emission and noise of diesel engine under high-altitude area

    NASA Astrophysics Data System (ADS)

    Xu, Kai; Huang, Hua

    2018-05-01

    At high altitudes and with no any adjustment for diesel engine, comparative experiments on a diesel engine about the engine's performance, emission and exhaust noise, are carried out by combusting different biofuels (pure diesel (D100), biodiesel (B100), and ethanol-biodiesel (E20)). The test results show that: compared with D100, the power performance of combusting B100 and E20 decreases, and the average drop of the torque at full-load are 4.5% and 5.7%. The equivalent fuel consumption is lower than that of diesel fuel, The decline of oil consumption rate 3˜10g/ (kW • h); At low load the emission of NOx decreases, Hat high loads, equal and higher than D100; the soot emissions decreases heavier, among them, E20 carbon dioxide emissions improved considerably; An full-load exhaust noise of B100 decreases average 3.6dB(A), E20 decreases average 4.8dB(A); In road simulation experiments exhaust noise max decreases 8.5dB(A).

  8. Stability and Workload of the Virtual Reality-Based Simulator-2.

    PubMed

    Kamaraj, Deepan C; Dicianno, Brad E; Mahajan, Harshal P; Buhari, Alhaji M; Cooper, Rory A

    2016-07-01

    To assess the stability of clinicians' and users' rating of electric-powered wheelchair (EPW) driving while using 4 different human-machine interfaces (HMIs) within the Virtual Reality-based SIMulator-version 2 (VRSIM-2) and in the real world (accounting for a total of 5 unique driving conditions). Within-subjects repeated-measures design. Simulation-based assessment in a research laboratory. A convenience sample of EPW athletes (N=21) recruited at the 31st National Veterans Wheelchair Games. Not applicable. Composite PMRT scores from the Power Mobility Road Test (PMRT); Raw Task Load Index; and the 6 subscale scores from the Task Load Index developed by the National Aeronautics and Space Administration (NASA-TLX). There was moderate stability (intraclass correlation coefficient between .50 and .75) in the total composite PMRT scores (P<.001) and the users' self-reported performance scores (P<.001) among the 5 driving conditions. There was a significant difference in the workload among the 5 different driving conditions as reflected by the Raw Task Load Index (P=.009). Subanalyses revealed this difference was due to the difference in the mental demand (P=.007) and frustration (P=.007) subscales. Post hoc analyses revealed that these differences in the NASA-TLX subscale scores were due to the differences between real-world and virtual driving scores, particularly attributable to the conditions (1 and 3) that lacked the rollers as a part of the simulation. Further design improvements in the simulator to increase immersion experienced by the EPW user, along with a standardized training program for clinicians to deliver PMRT in VRSIM-2, could improve the stability between the different HMIs and real-world driving. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  9. 40 CFR 1066.310 - Coastdown procedures for heavy-duty vehicles.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... or road must not be excessive (considering factors such as road safety standards and effects on the.... To calculate the force due to grade use Section 11.5 of SAE J2263. (2) You must reach a top speed of... rotational inertia of the wheels and tires. (iii) Calculate the road-load force for each measurement interval...

  10. 40 CFR 1066.310 - Coastdown procedures for heavy-duty vehicles.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... or road must not be excessive (considering factors such as road safety standards and effects on the.... To calculate the force due to grade use Section 11.5 of SAE J2263. (2) You must reach a top speed of... rotational inertia of the wheels and tires. (iii) Calculate the road-load force for each measurement interval...

  11. System reliability of randomly vibrating structures: Computational modeling and laboratory testing

    NASA Astrophysics Data System (ADS)

    Sundar, V. S.; Ammanagi, S.; Manohar, C. S.

    2015-09-01

    The problem of determination of system reliability of randomly vibrating structures arises in many application areas of engineering. We discuss in this paper approaches based on Monte Carlo simulations and laboratory testing to tackle problems of time variant system reliability estimation. The strategy we adopt is based on the application of Girsanov's transformation to the governing stochastic differential equations which enables estimation of probability of failure with significantly reduced number of samples than what is needed in a direct simulation study. Notably, we show that the ideas from Girsanov's transformation based Monte Carlo simulations can be extended to conduct laboratory testing to assess system reliability of engineering structures with reduced number of samples and hence with reduced testing times. Illustrative examples include computational studies on a 10-degree of freedom nonlinear system model and laboratory/computational investigations on road load response of an automotive system tested on a four-post test rig.

  12. Assessing the ground vibrations produced by a heavy vehicle traversing a traffic obstacle.

    PubMed

    Ducarne, Loïc; Ainalis, Daniel; Kouroussis, Georges

    2018-01-15

    Despite advancements in alternative transport networks, road transport remains the dominant mode in many modern and developing countries. The ground-borne motions produced by the passage of a heavy vehicle over a geometric obstacle (e.g. speed hump, train tracks) pose a fundamental problem in transport annoyance in urban areas. In order to predict the ground vibrations generated by the passage of a heavy vehicle over a geometric obstacle, a two-step numerical model is developed. The first step involves simulating the dynamic loads generated by the heavy vehicle using a multibody approach, which includes the tyre-obstacle-ground interaction. The second step involves the simulation of the ground wave propagation using a three dimensional finite element model. The simulation is able to be decoupled due to the large difference in stiffness between the vehicle's tyres and the road. First, the two-step model is validated using an experimental case study available in the literature. A sensitivity analysis is then presented, examining the influence of various factors on the generated ground vibrations. Factors investigated include obstacle shape, obstacle dimensions, vehicle speed, and tyre stiffness. The developed model can be used as a tool in the early planning stages to predict the ground vibrations generated by the passage of a heavy vehicle over an obstacle in urban areas. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Monitoring load distribution and fatigue cost estimates of heavy truck loads on Louisiana state bridges : tech summary.

    DOT National Transportation Integrated Search

    2013-11-01

    TEA 21 (Transportation Equity Act 21) of 1998 allows heavy sugarcane truck loads on Louisiana interstate highways. These heavier loads are currently being : applied to state and parish roads through trucks traveling from and to the processing plants....

  14. Dissolved-solids sources, loads, yields, and concentrations in streams of the conterminous United States

    USGS Publications Warehouse

    Anning, David W.; Flynn, Marilyn E.

    2014-01-01

    Results from the trend analysis and from the SPARROW model indicate that, compared to monitoring stations with no trends or decreasing trends, stations with increasing trends are associated with a smaller percentage of the predicted dissolved-solids load originating from geologic sources, and a larger percentage originating from urban lands and road deicers. Conversely, compared to stations with increasing trends or no trends, stations with decreasing trends have a larger percentage of the predicted dissolved-solids load originating from geologic sources and a smaller percentage originating from urban lands and road deicers. Stations with decreasing trends also have larger percentages of predicted dissolved-solids load originating from cultivated lands and pasture lands, compared to stations with increasing trends or no trends.

  15. Overload truck wheel load distribution on bridge decks.

    DOT National Transportation Integrated Search

    2009-04-01

    There is a need to accurately analyze the load effects on bridge decks from permitted overload trucks on : Michigans roads. The AASHTO Standard Specifications for Highway Bridges, 17th edition, provides a : distribution width of live loads when re...

  16. Response of Iowa pavements to heavy agricultural loads.

    DOT National Transportation Integrated Search

    1999-12-01

    Iowa's county road system includes several thousands of miles of paved roads which : consist of portland cement concrete (PCC) surfaces, asphalt cement concrete (ACC) surfaces, : and combinations of thin surface treatments such as seal coats and slur...

  17. Seasonal load restriction tool : Clarus regional demonstrations.

    DOT National Transportation Integrated Search

    2011-01-01

    State transportation agencies have wanted to improve : the techniques that lead to the decisions to impose and : subsequently lift restrictions on selected roads that are prone : to road damage due to subsurface freezing/thawing processes. : The Seas...

  18. A numerical forecast model for road meteorology

    NASA Astrophysics Data System (ADS)

    Meng, Chunlei

    2017-05-01

    A fine-scale numerical model for road surface parameters prediction (BJ-ROME) is developed based on the Common Land Model. The model is validated using in situ observation data measured by the ROSA road weather stations of Vaisala Company, Finland. BJ-ROME not only takes into account road surface factors, such as imperviousness, relatively low albedo, high heat capacity, and high heat conductivity, but also considers the influence of urban anthropogenic heat, impervious surface evaporation, and urban land-use/land-cover changes. The forecast time span and the update interval of BJ-ROME in vocational operation are 24 and 3 h, respectively. The validation results indicate that BJ-ROME can successfully simulate the diurnal variation of road surface temperature both under clear-sky and rainfall conditions. BJ-ROME can simulate road water and snow depth well if the artificial removing was considered. Road surface energy balance in rainy days is quite different from that in clear-sky conditions. Road evaporation could not be neglected in road surface water cycle research. The results of sensitivity analysis show solar radiation correction coefficient, asphalt depth, and asphalt heat conductivity are important parameters in road interface temperatures simulation. The prediction results could be used as a reference of maintenance decision support system to mitigate the traffic jam and urban water logging especially in large cities.

  19. Evaluation of Geosynthetic-Reinforced Flexible Pavements using Static Plate Load Tests

    DOT National Transportation Integrated Search

    2010-01-01

    This study focuses on the response of full-scale geogrid-reinforced flexible pavements to static surface loading. Specifically, static plate load (SPL) tests were performed on a low-volume, asphalt pavement frontage road in Eastern Arkansas, USA (the...

  20. 40 CFR 1066.210 - Dynamometers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... chassis dynamometer typically uses electrically generated load forces combined with its rotational inertia... (known as “road load”). Load forces are calculated using vehicle-specific coefficients and response characteristics. The load forces are applied to the vehicle tires by rolls connected to intermediate motor...

  1. 40 CFR 1066.210 - Dynamometers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... chassis dynamometer typically uses electrically generated load forces combined with its rotational inertia... (known as “road load”). Load forces are calculated using vehicle-specific coefficients and response characteristics. The load forces are applied to the vehicle tires by rolls connected to intermediate motor...

  2. Real-time weigh-in-motion measurement using fiber Bragg grating sensors

    NASA Astrophysics Data System (ADS)

    Huang, Ying; Palek, Leonard; Strommen, Robert; Worel, Ben; Chen, Genda

    2014-03-01

    Overloading truck loads have long been one of the key reasons for accelerating road damage, especially in rural regions where the design loads are expected to be small and in the cold regions where the wet-and-dry cycle places a significant role. To control the designed traffic loads and further guide the road design in future, periodical weight stations have been implemented for double check of the truck loads. The weight stations give chances for missing measurement of overloaded vehicles, slow down the traffic, and require additional labors. Infrastructure weight-in-motion sensors, on the other hand, keep consistent traffic flow and monitor all types of vehicles on roads. However, traditional electrical weight-in-motion sensors showed high electromagnetic interference (EMI), high dependence on environmental conditions such as moisture, and relatively short life cycle, which are unreliable for long-term weigh-inmotion measurements. Fiber Bragg grating (FBG) sensors, with unique advantages of compactness, immune to EMI and moisture, capability of quasi-distributed sensing, and long life cycle, will be a perfect candidate for long-term weigh-in-motion measurements. However, the FBG sensors also surfer from their frangible nature of glass materials for a good survive rate during sensor installation. In this study, the FBG based weight-in-motion sensors were packaged by fiber reinforced polymer (FRP) materials and further validated at MnROAD facility, Minnesota DOT (MnDOT). The design and layout of the FRP-FBG weight-in-motion sensors, their field test setup, data acquisition, and data analysis will be presented. Upon validation, the FRP-FBG sensors can be applied weigh-in-motion measurement to assistant road managements.

  3. Research and Development for Off-Road Fuel Cell Applications U.S. Department of Energy Grant DE-FG36-04GO14303 - Final Report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hicks, Michael; Erickson, Paul; Lawrence, Richard

    Off-road concerns are related to the effects of shock and vibration and air quality on fuel cell power requirements. Mechanical stresses on differing material makeup and mass distribution within the system may render some components susceptible to impulse trauma while others may show adverse effects from harmonic disturbances or broad band mechanical agitation. One of the recognized challenges in fuel cell systems air purification is in providing a highly efficient particulate and chemical filter with minimal pressure drop. PEM integrators do not want additional parasitic loads added to the system as compensation for a highly efficient yet highly restrictive filter.more » Additionally, there is challenge in integrating multiple functions into a single air intake module tasked with effectively filtering high dust loads, diesel soot, pesticides, ammonias, and other anticipated off-road contaminants. This project has investigated both off-road associated issues cumulating in the prototype build and testing of two light duty off-road vehicles with integrated fuel cell power plant systems.« less

  4. Development of Environmental Load Estimation Model for Road Drainage Systems in the Early Design Phase

    NASA Astrophysics Data System (ADS)

    Park, Jin-Young; Lee, Dong-Eun; Kim, Byung-Soo

    2017-10-01

    Due to the increasing concern about climate change, efforts to reduce environmental load are continuously being made in construction industry, and LCA (life cycle assessment) is being presented as an effective method to assess environmental load. Since LCA requires information on construction quantity used for environmental load estimation, however, it is not being utilized in the environmental review in the early design phase where it is difficult to obtain such information. In this study, computation system for construction quantity based on standard cross section of road drainage facilities was developed to compute construction quantity required for LCA using only information available in the early design phase to develop and verify the effectiveness of a model that can perform environmental load estimation. The result showed that it is an effective model that can be used in the early design phase as it revealed a 13.39% mean absolute error rate.

  5. The effect of billboard design specifications on driving: A pilot study.

    PubMed

    Marciano, Hadas; Setter, Pe'erly

    2017-07-01

    Decades of research on the effects of advertising billboards on road accident rates, driver performance, and driver visual scanning behavior, has produced no conclusive findings. We suggest that road safety researchers should shift their focus and attempt to identify the billboard characteristics that are most distracting to drivers. This line of research may produce concrete guidelines for permissible billboards that would be likely to reduce the influence of the billboards on road safety. The current study is a first step towards this end. A pool of 161 photos of real advertising billboards was used as stimuli within a triple task paradigm designed to simulate certain components of driving. Each trial consisted of one ongoing tracking task accompanied by two additional concurrent tasks: (1) billboard observation task; and (2) circle color change identification task. Five clusters of billboards, identified by conducting a cluster analysis of their graphic content, were used as a within variable in one-way ANOVAs conducted on performance level data collected from the multiple tasks. Cluster 5, labeled Loaded Billboards, yielded significantly deteriorated performance on the tracking task. Cluster 4, labeled Graphical Billboards, yielded deteriorated performance primarily on the color change identification task. Cluster 3, labeled Minimal Billboards, had no effect on any of these tasks. We strongly recommend that these clusters be systematically explored in experiments involving additional real driving settings, such as driving simulators and field studies. This will enable validation of the current results and help incorporate them into real driving situations. Copyright © 2017. Published by Elsevier Ltd.

  6. Pregnant woman and road safety: experimental crash test with post mortem human subject.

    PubMed

    Delotte, Jerome; Behr, Michel; Thollon, Lionel; Arnoux, Pierre-Jean; Baque, Patrick; Bongain, Andre; Brunet, Christian

    2008-05-01

    Trauma affect between 3 and 7% of all pregnancies in industrialized countries, and the leading cause of these traumas is car crashes. The difficulty to appreciate physiologic and anatomic changes occurring during pregnancy explain that majority of studies were not based on anatomical data. We present a protocol to create a realistic anatomical model of pregnant woman using a post mortem human subject (PMHS). We inserted a physical model of the gravid uterus into the pelvis of a PMHS. 3D acceleration sensors were placed on the subject to measure the acceleration on different body segments. We simulated three frontal impact situations at 20 km/h between two average European cars. Two main kinematics events were identified as possible causes of injuries: lap belt loading and backrest impact. Cadaver experiments provide one interesting complementary approach to study injury mechanisms related to road accidents involving pregnant women. This anatomical accuracy makes it possible to progress in the field of safety devices.

  7. 36 CFR § 1004.11 - Load, weight and size limits.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... designate more restrictive limits when appropriate for traffic safety or protection of the road surface. The... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Load, weight and size limits... TRAFFIC SAFETY § 1004.11 Load, weight and size limits. (a) Vehicle load, weight and size limits...

  8. Thaw weakening and load restriction practices on low volume roads

    DOT National Transportation Integrated Search

    2000-06-01

    Low volume roads subjected to seasonal freezing are highly susceptible to damage from traffic during midwinter and spring thaws. Such traffic-induced damage can be minimized by a variety of design methods; however, most are not economically feasible....

  9. Effects of Wheel-Load Spatial Repeatability on Road Damage : A Literature Review

    DOT National Transportation Integrated Search

    1998-09-01

    Concerns about growing governmental budgetary deficits and the awareness of the economic advantages associated with a safe and well-maintained road infrastructure are two of the main reasons for devoting attention to better understanding the problem ...

  10. Pollutant loads of surface runoff in Wuhan City Zoo, an urban tourist area.

    PubMed

    Zhao, Jian-wei; Shan, Bao-qing; Yin, Cheng-qing

    2007-01-01

    The pollutant loads of surface runoff in an urban tourist area have been investigated for two years in the Wuhan City Zoo, China. Eight sampling sites, including two woodlands, three animal yards, two roofs and one road, were selected for sampling and study. The results indicate that pollutants ranked in a predictable order of decreasing load (e.g. animal yard > roof > woodland > road), with animal yards acting as the key pollution source in the zoo. Pollutants were transported mainly by particulate form in runoff. Particulate nitrogen and particulate phosphorous accounted on average for 61%, 78% of total pollutant, respectively, over 13 monitored rainfall events. These results indicate the treatment practices should be implemented to improve particulate nutrient removal. Analysis of the M(V) curve indicate that no first flush effect existed in the surface runoff from pervious areas (e.g. woodland, animal ground yard), whereas a first flush effect was evident in runoff from impervious surfaces (e.g. animal cement yard, roof, road).

  11. Driver steering dynamics measured in car simulator under a range of visibility and roadmaking conditions

    NASA Technical Reports Server (NTRS)

    Allen, R. W.; Mcruer, D. T.

    1977-01-01

    A simulation experiment was conducted to determine the effect of reduced visibility on driver lateral (steering) control. The simulator included a real car cab and a single lane road image projected on a screen six feet in front of the driver. Simulated equations of motion controlled apparent car lane position in response to driver steering actions, wind gusts, and road curvature. Six drivers experienced a range of visibility conditions at various speeds with assorted roadmaking configurations (mark and gap lengths). Driver describing functions were measured and detailed parametric model fits were determined. A pursuit model employing a road curvature feedforward was very effective in explaining driver behavior in following randomly curving roads. Sampled-data concepts were also effective in explaining the combined effects of reduced visibility and intermittent road markings on the driver's dynamic time delay. The results indicate the relative importance of various perceptual variables as the visual input to the driver's steering control process is changed.

  12. SIMPAVE : towards building interactive simulations for planning pavement construction

    DOT National Transportation Integrated Search

    2007-04-01

    The goal of this project is to produce a software simulation that enables a user to manage a road construction project from the hot mix asphalt plant operation to the finished paved road. Throughout the simulation, the user is provided with the resou...

  13. Optimization design of urban expressway ramp control

    NASA Astrophysics Data System (ADS)

    Xu, Hongke; Li, Peiqi; Zheng, Jinnan; Sun, Xiuzhen; Lin, Shan

    2017-05-01

    In this paper, various types of expressway systems are analyzed, and a variety of signal combinations are proposed to mitigate traffic congestion. And various signal combinations are used to verify the effectiveness of the multi-signal combinatorial control strategy. The simulation software VISSIM was used to simulate the system. Based on the network model of 25 kinds of road length combinations and the simulation results, an optimization scheme suitable for the practical road model is summarized. The simulation results show that the controller can reduce the travel time by 25% under the large traffic flow and improve the road capacity by about 20%.

  14. Assessing the Driver’s Current Level of Working Memory Load with High Density Functional Near-infrared Spectroscopy: A Realistic Driving Simulator Study

    PubMed Central

    Unni, Anirudh; Ihme, Klas; Jipp, Meike; Rieger, Jochem W.

    2017-01-01

    Cognitive overload or underload results in a decrease in human performance which may result in fatal incidents while driving. We envision that driver assistive systems which adapt their functionality to the driver’s cognitive state could be a promising approach to reduce road accidents due to human errors. This research attempts to predict variations of cognitive working memory load levels in a natural driving scenario with multiple parallel tasks and to reveal predictive brain areas. We used a modified version of the n-back task to induce five different working memory load levels (from 0-back up to 4-back) forcing the participants to continuously update, memorize, and recall the previous ‘n’ speed sequences and adjust their speed accordingly while they drove for approximately 60 min on a highway with concurrent traffic in a virtual reality driving simulator. We measured brain activation using multichannel whole head, high density functional near-infrared spectroscopy (fNIRS) and predicted working memory load level from the fNIRS data by combining multivariate lasso regression and cross-validation. This allowed us to predict variations in working memory load in a continuous time-resolved manner with mean Pearson correlations between induced and predicted working memory load over 15 participants of 0.61 [standard error (SE) 0.04] and a maximum of 0.8. Restricting the analysis to prefrontal sensors placed over the forehead reduced the mean correlation to 0.38 (SE 0.04), indicating additional information gained through whole head coverage. Moreover, working memory load predictions derived from peripheral heart rate parameters achieved much lower correlations (mean 0.21, SE 0.1). Importantly, whole head fNIRS sampling revealed increasing brain activation in bilateral inferior frontal and bilateral temporo-occipital brain areas with increasing working memory load levels suggesting that these areas are specifically involved in workload-related processing. PMID:28424602

  15. Assessing the Driver's Current Level of Working Memory Load with High Density Functional Near-infrared Spectroscopy: A Realistic Driving Simulator Study.

    PubMed

    Unni, Anirudh; Ihme, Klas; Jipp, Meike; Rieger, Jochem W

    2017-01-01

    Cognitive overload or underload results in a decrease in human performance which may result in fatal incidents while driving. We envision that driver assistive systems which adapt their functionality to the driver's cognitive state could be a promising approach to reduce road accidents due to human errors. This research attempts to predict variations of cognitive working memory load levels in a natural driving scenario with multiple parallel tasks and to reveal predictive brain areas. We used a modified version of the n-back task to induce five different working memory load levels (from 0-back up to 4-back) forcing the participants to continuously update, memorize, and recall the previous 'n' speed sequences and adjust their speed accordingly while they drove for approximately 60 min on a highway with concurrent traffic in a virtual reality driving simulator. We measured brain activation using multichannel whole head, high density functional near-infrared spectroscopy (fNIRS) and predicted working memory load level from the fNIRS data by combining multivariate lasso regression and cross-validation. This allowed us to predict variations in working memory load in a continuous time-resolved manner with mean Pearson correlations between induced and predicted working memory load over 15 participants of 0.61 [standard error (SE) 0.04] and a maximum of 0.8. Restricting the analysis to prefrontal sensors placed over the forehead reduced the mean correlation to 0.38 (SE 0.04), indicating additional information gained through whole head coverage. Moreover, working memory load predictions derived from peripheral heart rate parameters achieved much lower correlations (mean 0.21, SE 0.1). Importantly, whole head fNIRS sampling revealed increasing brain activation in bilateral inferior frontal and bilateral temporo-occipital brain areas with increasing working memory load levels suggesting that these areas are specifically involved in workload-related processing.

  16. Direction based Hazard Routing Protocol (DHRP) for disseminating road hazard information using road side infrastructures in VANETs.

    PubMed

    Berlin, M A; Anand, Sheila

    2014-01-01

    This paper presents Direction based Hazard Routing Protocol (DHRP) for disseminating information about fixed road hazards such as road blocks, tree fall, boulders on road, snow pile up, landslide, road maintenance work and other obstacles to the vehicles approaching the hazardous location. The proposed work focuses on dissemination of hazard messages on highways with sparse traffic. The vehicle coming across the hazard would report the presence of the hazard. It is proposed to use Road Side fixed infrastructure Units for reliable and timely delivery of hazard messages to vehicles. The vehicles can then take appropriate safety action to avoid the hazardous location. The proposed protocol has been implemented and tested using SUMO simulator to generate road traffic and NS 2.33 network simulator to analyze the performance of DHRP. The performance of the proposed protocol was also compared with simple flooding protocol and the results are presented.

  17. Optimal handgrip height of four-wheeled walker on various road conditions to reduce muscular load for elderly users with steady walking.

    PubMed

    Takanokura, Masato

    2010-03-22

    A four-wheeled walker is a valuable tool for assisting elderly persons with walking. The handgrip height is one of the most important factor determining the usefulness of the walker. However, the optimal handgrip height for elderly users has not been considered from a biomechanical viewpoint. In this study, the handgrip height was optimized by a two-dimensional mechanical model to reduce muscular loads in the lower body as well as in the upper body with various road conditions during steady walking. A critical height of the handgrip existed at 48% of the body height for the user regardless of gender and body dimension. A lower handgrip relieved muscular load for stooping users with a lower standing height. The stooping user pushed the handgrip strongly in the perpendicular direction by leaning the upper body on the walker. However, upright users with a higher standing height should use a four-wheeled walker with a higher handgrip for maintaining his or her upright posture. For downhill movement, the optimal handgrip height depended on the slope angle and the friction coefficient between the road and the wheels of the walker. On a low-friction downhill such as asphalt with a steeper slope angle, the user was required to maintain an erect trunk with a higher handgrip and to press on the handgrip strongly in the perpendicular direction. Movement on a low-friction road was easier for users on a flat road and an uphill road, but it compelled distinct effort from users when moving downhill. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

  18. Climate Change Impacts on Transportation; Groundwater Elevation, Road Performance, and Robust Adaptation

    NASA Astrophysics Data System (ADS)

    Kirshen, P. H.; Knott, J. F.; Ray, P.; Elshaer, M.; Daniel, J.; Jacobs, J. M.

    2016-12-01

    Transportation climate change vulnerability and adaptation studies have primarily focused on surface-water flooding from sea-level rise (SLR); little attention has been given to the effects of climate change and SLR on groundwater and subsequent impacts on the unbound foundation layers of coastal-road infrastructure. The magnitude of service-life reduction depends on the height of the groundwater in the unbound pavement materials, the pavement structure itself, and the loading. Using a steady-state groundwater model, and a multi-layer elastic pavement evaluation model, the strain changes in the layers can be determined as a function of parameter values and the strain changes translated into failure as measured by number of loading cycles to failure. For a section of a major coastal road in New Hampshire, future changes in sea-level, precipitation, temperature, land use, and groundwater pumping are characterized by deep uncertainty. Parameters that describe the groundwater system such as hydraulic conductivity can be probabilistically described while road characteristics are assumed to be deterministic. To understand the vulnerability of this road section, a bottom-up planning approach was employed over time where the combinations of parameter values that cause failure were determined and their plausibility of their occurring was analyzed. To design a robust adaptation strategy that will function reasonably well in the present and the future given the large number of uncertain parameter values, performance of adaptation options were investigated. Adaptation strategies that were considered include raising the road, load restrictions, increasing pavement layer thicknesses, replacing moisture-sensitive materials with materials that are not moisture sensitive, improving drainage systems, and treatment of the underlying materials.

  19. Analysis of Road Network Pattern Considering Population Distribution and Central Business District

    PubMed Central

    Zhao, Fangxia; Sun, Huijun; Wu, Jianjun; Gao, Ziyou; Liu, Ronghui

    2016-01-01

    This paper proposes a road network growing model with the consideration of population distribution and central business district (CBD) attraction. In the model, the relative neighborhood graph (RNG) is introduced as the connection mechanism to capture the characteristics of road network topology. The simulation experiment is set up to illustrate the effects of population distribution and CBD attraction on the characteristics of road network. Moreover, several topological attributes of road network is evaluated by using coverage, circuitness, treeness and total length in the experiment. Finally, the suggested model is verified in the simulation of China and Beijing Highway networks. PMID:26981857

  20. 36 CFR 1004.11 - Load, weight and size limits.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... limits when appropriate for traffic safety or protection of the road surface. The Board may require a... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false Load, weight and size limits... § 1004.11 Load, weight and size limits. (a) Vehicle load, weight and size limits established by State law...

  1. 36 CFR 1004.11 - Load, weight and size limits.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... limits when appropriate for traffic safety or protection of the road surface. The Board may require a... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Load, weight and size limits... § 1004.11 Load, weight and size limits. (a) Vehicle load, weight and size limits established by State law...

  2. 36 CFR 1004.11 - Load, weight and size limits.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... limits when appropriate for traffic safety or protection of the road surface. The Board may require a... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Load, weight and size limits... § 1004.11 Load, weight and size limits. (a) Vehicle load, weight and size limits established by State law...

  3. Using chloride and other ions to trace sewage and road salt in the Illinois Waterway

    USGS Publications Warehouse

    Kelly, W.R.; Panno, S.V.; Hackley, Keith C.; Hwang, H.-H.; Martinsek, A.T.; Markus, M.

    2010-01-01

    Chloride concentrations in waterways of northern USA are increasing at alarming rates and road salt is commonly assumed to be the cause. However, there are additional sources of Cl- in metropolitan areas, such as treated wastewater (TWW) and water conditioning salts, which may be contributing to Cl- loads entering surface waters. In this study, the potential sources of Cl- and Cl- loads in the Illinois River Basin from the Chicago area to the Illinois River's confluence with the Mississippi River were investigated using halide data in stream samples and published Cl- and river discharge data. The investigation showed that road salt runoff and TWW from the Chicago region dominate Cl- loads in the Illinois Waterway, defined as the navigable sections of the Illinois River and two major tributaries in the Chicago region. Treated wastewater discharges at a relatively constant rate throughout the year and is the primary source of Cl- and other elements such as F- and B. Chloride loads are highest in the winter and early spring as a result of road salt runoff which can increase Cl- concentrations by up to several hundred mg/L. Chloride concentrations decrease downstream in the Illinois Waterway due to dilution, but are always elevated relative to tributaries downriver from Chicago. The TWW component is especially noticeable downstream under low discharge conditions during summer and early autumn when surface drainage is at a minimum and agricultural drain tiles are not flowing. Increases in population, urban and residential areas, and roadways in the Chicago area have caused an increase in the flux of Cl- from both road salt and TWW. Chloride concentrations have been increasing in the Illinois Waterway since around 1960 at a rate of about 1 mg/L/a. The increase is largest in the winter months due to road salt runoff. Shallow groundwater Cl- concentrations are also increasing, potentially producing higher base flow concentrations. Projected increases in population and urbanization over the next several decades suggest that the trend of increasing Cl- concentrations and loads will continue. Given the susceptibility of aquatic ecosystems to increasing Cl- concentrations, especially short-term spikes following snow melts, deleterious effects on riverine ecosystems would be expected. ?? 2010 Elsevier Ltd. All rights reserved.

  4. Investigating the road surface effect to the fatigue life of an automotive coil spring

    NASA Astrophysics Data System (ADS)

    Putra, T. E.; Husaini

    2018-05-01

    This work aims to estimate the life of a coil spring considering road surface profiles. Strain signals were measured by installing a strain gage at the highest stress location of the coil spring and then driving the vehicle on country and village roads. The village road gave high amplitudes containing spikes when the tire touched a curb, bump or pothole. These conditions contributed to a higher loading rate to the car component, contributing to shorter useful fatigue life, which was only 140 reversals of blocks. Driving on the village road resulted in a 6-times decrease in the useful fatigue life of the component in comparison to the country road. In conclusion, the village road caused stronger vibrations to the component because it has a rough surface; meanwhile, the country road provided lower vibrations because the road was smooth.

  5. Effects of Highway Road Salting on the Water Quality of Selected Streams in Chittenden County, Vermont, November 2005-2007

    USGS Publications Warehouse

    Denner, Jon C.; Clark, Stewart F.; Smith, Thor E.; Medalie, Laura

    2010-01-01

    A study of road-deicing chloride (Cl) concentrations and loads was conducted at three streams in Chittenden County, VT, from November 2005 to 2007. This study was done by the U.S. Geological Survey, in cooperation with the Vermont Agency of Transportation. The streams, Alder Brook, Allen Brook, and Mill Brook, were selected to represent different land uses in the upstream watershed, different road types and densities, and different geometric patterns of the roadway draining to the receiving stream to assess the relative contribution of and differences in state road-salt applications to stream Cl concentrations and loads. Water-quality samples were collected and specific conductance was measured continuously at paired stations upstream and downstream from State highways and related to Cl concentrations to assist in determining the effects of road-salting operations during winter maintenance on the levels of Cl in the streams. Mean concentrations of Cl ranged from 8.2 to 72 mg/L (milligrams per liter) in the water-quality samples collected at sampling stations upstream from State highway bridges and from 7.9 to 80 mg/L in those collected at sampling stations downstream of highway bridges. Mean Cl loads ranged from 1,100 to 4,090 lb/d (pounds per day) at upstream stations and from 1,110 to 4,200 lb/d at downstream stations. Estimated mean annual Cl loads ranged from 402,000 to 1,490,000 lb/yr (pounds per year) at upstream stations and from 405,000 to 1,530,000 lb/yr at downstream stations. Mean Cl concentrations in samples collected at the three paired stations were lowest at Mill Brook at VT 117 near Essex Junction, VT (7.9 mg/L) and highest at Allen Brook at VT 2A near Essex Junction, VT (80.7 mg/L). None of the monitored Cl concentrations in the water-quality samples collected at the three paired sampling stations exceeded either of the U.S. Environmental Protection Agency's (USEPA) recommended chronic and acute Cl toxicity criteria of 230 and 860 mg/L, respectively. A fourth stream site, a small tributary draining to Alder Brook between the upstream and downstream stations, was monitored from December 2006 to November 2007. This tributary collected runoff from a state highway and an interchange before flowing through a wetlands retention basin. The mean Cl concentration in water-quality samples collected at the tributary was 449 mg/L. The USEPA recommended chronic toxicity criterion of 230 mg/L was exceeded about 65 percent of the monitoring period. The USEPA recommended acute toxicity criterion of 860 mg/L was not exceeded. Estimated Cl loads below the State highway bridges exceeded loads above the bridges at all three paired stations during both years of the study. The differences in the annual loads between the upstream and downstream stations were 0.7, 3.0 and 14 percent at Mill, Allen, and Alder Brooks, respectively. Almost all of the difference (92 percent) at Alder Brook was due to the tributary. Cl applied by the State of Vermont for deicing purposes represented less than 20 percent of the annual estimated Cl load in all 3 streams below the state highways. The highest monthly Cl loads during the first year of the study were observed in January 2006 at all three stream stations because of an early snowmelt event. The highest monthly Cl loads during the second year of the study were observed in April 2007 at all three streams during spring snowmelt and were followed by decrease in Cl loading through the summer. Generally, the relation of Cl loads to runoff was similar at all three streams. In July and October 2007, loads increased slightly with an increase in runoff, indicating that Cl in the soils and groundwater may be contributing to the Cl levels during the summer and fall, well after the road-salting season. Cl loads in all three streams appear to be due primarily to sources in the watersheds upstream of the state highway bridge where road salt was applied and (or) Cl retained in soils and streambed

  6. Performance evaluation of high modulus asphalt concrete mixes

    NASA Astrophysics Data System (ADS)

    Haritonovs, V.; Tihonovs, J.; Zaumanis, M.

    2016-04-01

    Dolomite is one of the most available sedimentary rocks in the territory of Latvia. Dolomite quarries contain about 1000 million tons of this material. However, according to Latvian Road Specifications, this dolomite cannot be used for average and high intensity roads because of its low quality (mainly, LA index). Therefore, mostly imported magmatic rocks (granite, diabase, gabbro, basalt) or imported dolomite are used which makes asphalt expensive. However, practical experience shows that even with these high quality materials roads exhibit rutting, fatigue and thermal cracks. The aim of the research is to develop a high performance asphalt concrete for base and binder courses using only locally available aggregates. In order to achieve resistance against deformations at a high ambient temperature, a hard grade binder was used. Workability, fatigue and thermal cracking resistance, as well as sufficient water resistance is achieved by low porosity (3-5%) and higher binder content compared to traditional asphalt mixtures. The design of the asphalt includes a combination of empirical and performance based tests, which in laboratory circumstances allow simulating traffic and environmental loads. High performance AC 16 base asphalt concrete was created using local dolomite aggregate with polymer modified (PMB 10/40-65) and hard grade (B20/30) bitumen. The mixtures were specified based on fundamental properties in accordance to EN 13108-1 standard.

  7. Traffic generated non-exhaust particulate emissions from concrete pavement: A mass and particle size study for two-wheelers and small cars

    NASA Astrophysics Data System (ADS)

    Aatmeeyata; Kaul, D. S.; Sharma, Mukesh

    This study aimed to understand the non-exhaust (NE) emission of particles from wear of summer tire and concrete pavement, especially for two wheelers and small cars. A fully enclosed laboratory-scale model was fabricated to simulate road tire interaction with a facility to collect particles in different sizes. A road was cast using the M-45 concrete mixture and the centrifugal casting method. It was observed that emission of large particle non exhaust emission (LPNE) as well as PM 10 and PM 2.5 increased with increasing load. The LPNE was 3.5 mg tire -1 km -1 for a two wheeler and 6.4 mg tire -1 km -1 for a small car. The LPNE can lead to water pollution through water run-off from the roads. The contribution of the PM 10 and PM 2.5 was smaller compared to the LPNE particles (less than 0.1%). About 32 percent of particle mass of PM 10 was present below 1 μm. The number as well as mass size distribution for PM 10 was observed to be bi-modal with peaks at 0.3 μm and 4-5 μm. The NE emissions did not show any significant trend with change in tire pressure.

  8. A Beacon Transmission Power Control Algorithm Based on Wireless Channel Load Forecasting in VANETs.

    PubMed

    Mo, Yuanfu; Yu, Dexin; Song, Jun; Zheng, Kun; Guo, Yajuan

    2015-01-01

    In a vehicular ad hoc network (VANET), the periodic exchange of single-hop status information broadcasts (beacon frames) produces channel loading, which causes channel congestion and induces information conflict problems. To guarantee fairness in beacon transmissions from each node and maximum network connectivity, adjustment of the beacon transmission power is an effective method for reducing and preventing channel congestion. In this study, the primary factors that influence wireless channel loading are selected to construct the KF-BCLF, which is a channel load forecasting algorithm based on a recursive Kalman filter and employs multiple regression equation. By pre-adjusting the transmission power based on the forecasted channel load, the channel load was kept within a predefined range; therefore, channel congestion was prevented. Based on this method, the CLF-BTPC, which is a transmission power control algorithm, is proposed. To verify KF-BCLF algorithm, a traffic survey method that involved the collection of floating car data along a major traffic road in Changchun City is employed. By comparing this forecast with the measured channel loads, the proposed KF-BCLF algorithm was proven to be effective. In addition, the CLF-BTPC algorithm is verified by simulating a section of eight-lane highway and a signal-controlled urban intersection. The results of the two verification process indicate that this distributed CLF-BTPC algorithm can effectively control channel load, prevent channel congestion, and enhance the stability and robustness of wireless beacon transmission in a vehicular network.

  9. A Beacon Transmission Power Control Algorithm Based on Wireless Channel Load Forecasting in VANETs

    PubMed Central

    Mo, Yuanfu; Yu, Dexin; Song, Jun; Zheng, Kun; Guo, Yajuan

    2015-01-01

    In a vehicular ad hoc network (VANET), the periodic exchange of single-hop status information broadcasts (beacon frames) produces channel loading, which causes channel congestion and induces information conflict problems. To guarantee fairness in beacon transmissions from each node and maximum network connectivity, adjustment of the beacon transmission power is an effective method for reducing and preventing channel congestion. In this study, the primary factors that influence wireless channel loading are selected to construct the KF-BCLF, which is a channel load forecasting algorithm based on a recursive Kalman filter and employs multiple regression equation. By pre-adjusting the transmission power based on the forecasted channel load, the channel load was kept within a predefined range; therefore, channel congestion was prevented. Based on this method, the CLF-BTPC, which is a transmission power control algorithm, is proposed. To verify KF-BCLF algorithm, a traffic survey method that involved the collection of floating car data along a major traffic road in Changchun City is employed. By comparing this forecast with the measured channel loads, the proposed KF-BCLF algorithm was proven to be effective. In addition, the CLF-BTPC algorithm is verified by simulating a section of eight-lane highway and a signal-controlled urban intersection. The results of the two verification process indicate that this distributed CLF-BTPC algorithm can effectively control channel load, prevent channel congestion, and enhance the stability and robustness of wireless beacon transmission in a vehicular network. PMID:26571042

  10. A sonification algorithm for developing the off-roads models for driving simulators

    NASA Astrophysics Data System (ADS)

    Chiroiu, Veturia; Brişan, Cornel; Dumitriu, Dan; Munteanu, Ligia

    2018-01-01

    In this paper, a sonification algorithm for developing the off-road models for driving simulators, is proposed. The aim of this algorithm is to overcome difficulties of heuristics identification which are best suited to a particular off-road profile built by measurements. The sonification algorithm is based on the stochastic polynomial chaos analysis suitable in solving equations with random input data. The fluctuations are generated by incomplete measurements leading to inhomogeneities of the cross-sectional curves of off-roads before and after deformation, the unstable contact between the tire and the road and the unreal distribution of contact and friction forces in the unknown contact domains. The approach is exercised on two particular problems and results compare favorably to existing analytical and numerical solutions. The sonification technique represents a useful multiscale analysis able to build a low-cost virtual reality environment with increased degrees of realism for driving simulators and higher user flexibility.

  11. Evaluating the Impact of Road Grade on Simulated Commercial Vehicle Fuel Economy Using Real-World Drive Cycles

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lopp, Sean; Wood, Eric; Duran, Adam

    Commercial vehicle fuel economy is known to vary significantly with both positive and negative road grade. Medium- and heavy-duty vehicles operating at highway speeds require incrementally larger amounts of energy to pull heavy payloads up inclines as road grade increases. Non-hybrid vehicles are then unable to recapture energy on descent and lose energy through friction braking. While the on-road effects of road grade are well understood, the majority of standard commercial vehicle drive cycles feature no climb or descent requirements. Additionally, existing literature offers a limited number of sources that attempt to estimate the on-road energy implications of road grademore » in the medium- and heavy-duty space. This study uses real-world commercial vehicle drive cycles from the National Renewable Energy Laboratory's Fleet DNA database to simulate the effects of road grade on fuel economy across a range of vocations, operating conditions, and locations. Drive-cycles are matched with vocation-specific vehicle models and simulated with and without grade. Fuel use due to grade is presented, and variation in fuel consumption due to drive cycle and vehicle characteristics is explored through graphical and statistical comparison. The results of this study suggest that road grade accounts for 1%-9% of fuel use in commercial vehicles on average and up to 40% on select routes.« less

  12. 12. VIEW OF CANOPY OVER NORTHWEST LOADING PLATFORM, RUNNING NEARLY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    12. VIEW OF CANOPY OVER NORTHWEST LOADING PLATFORM, RUNNING NEARLY THE ENTIRE LENGTH OF THE BUILDING - Oakland Army Base, Transit Shed, East of Dunkirk Street & South of Burma Road, Oakland, Alameda County, CA

  13. 16. DETAIL VIEW OF NORTHWEST SIDE LOADING DOCKS, SHOWING SUSPENDER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. DETAIL VIEW OF NORTHWEST SIDE LOADING DOCKS, SHOWING SUSPENDER BARS AND ORIGINAL SHIPLAP SIDING - Oakland Army Base, Transit Shed, East of Dunkirk Street & South of Burma Road, Oakland, Alameda County, CA

  14. Rate of deterioration of bridges and pavements as affected by trucks.

    DOT National Transportation Integrated Search

    2013-12-01

    The largest loads on public road systems disproportionately inflict the greatest damage to highway : infrastructure. Simultaneously facing both increasing demand for overweight loads and deteriorating : pavement and bridges, the South Carolina Depart...

  15. Looking Northwest at First Floor Typical Wall and Ceiling Juncture ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking Northwest at First Floor Typical Wall and Ceiling Juncture in Oxide Building and Loading Dock - Hematite Fuel Fabrication Facility, Oxide Building & Oxide Loading Dock, 3300 State Road P, Festus, Jefferson County, MO

  16. Modeling multi-scale aerosol dynamics and micro-environmental air quality near a large highway intersection using the CTAG model.

    PubMed

    Wang, Yan Jason; Nguyen, Monica T; Steffens, Jonathan T; Tong, Zheming; Wang, Yungang; Hopke, Philip K; Zhang, K Max

    2013-01-15

    A new methodology, referred to as the multi-scale structure, integrates "tailpipe-to-road" (i.e., on-road domain) and "road-to-ambient" (i.e., near-road domain) simulations to elucidate the environmental impacts of particulate emissions from traffic sources. The multi-scale structure is implemented in the CTAG model to 1) generate process-based on-road emission rates of ultrafine particles (UFPs) by explicitly simulating the effects of exhaust properties, traffic conditions, and meteorological conditions and 2) to characterize the impacts of traffic-related emissions on micro-environmental air quality near a highway intersection in Rochester, NY. The performance of CTAG, evaluated against with the field measurements, shows adequate agreement in capturing the dispersion of carbon monoxide (CO) and the number concentrations of UFPs in the near road micro-environment. As a proof-of-concept case study, we also apply CTAG to separate the relative impacts of the shutdown of a large coal-fired power plant (CFPP) and the adoption of the ultra-low-sulfur diesel (ULSD) on UFP concentrations in the intersection micro-environment. Although CTAG is still computationally expensive compared to the widely-used parameterized dispersion models, it has the potential to advance our capability to predict the impacts of UFP emissions and spatial/temporal variations of air pollutants in complex environments. Furthermore, for the on-road simulations, CTAG can serve as a process-based emission model; Combining the on-road and near-road simulations, CTAG becomes a "plume-in-grid" model for mobile emissions. The processed emission profiles can potentially improve regional air quality and climate predictions accordingly. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. 23 CFR 650.307 - Bridge inspection organization.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... bridges located on public roads that are fully or partially located within the State's boundaries, except... inspected, all highway bridges located on public roads that are fully or partially located within the... preparation and maintenance of a bridge inventory. (2) Bridge inspections, reports, load ratings and other...

  18. 38 CFR 39.20 - Site planning standards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... proposed traffic flows and volumes. Primary roads are generally 24 feet wide. (4) Pavement design. The pavement section of all roads, service areas and parking areas shall be designed for the maximum anticipated traffic loads and existing soil conditions and in accordance with local and State design criteria...

  19. Isolation of Flaws by Use of Thermal Differentials on a Tire Under Mild Loading Conditions

    DOT National Transportation Integrated Search

    1972-02-01

    Twenty-six used and rebuilt solid rubber road wheels were examined by an infrared temperature profiling technique during drum test exercise. The IR method was evaluated as a nondestructive means of predicting road wheel integrity by analysis of the c...

  20. Modeling and simulation of emergent behavior in transportation infrastructure restoration

    USGS Publications Warehouse

    Ojha, Akhilesh; Corns, Steven; Shoberg, Thomas G.; Qin, Ruwen; Long, Suzanna K.

    2018-01-01

    The objective of this chapter is to create a methodology to model the emergent behavior during a disruption in the transportation system and that calculates economic losses due to such a disruption, and to understand how an extreme event affects the road transportation network. The chapter discusses a system dynamics approach which is used to model the transportation road infrastructure system to evaluate the different factors that render road segments inoperable and calculate economic consequences of such inoperability. System dynamics models have been integrated with business process simulation model to evaluate, design, and optimize the business process. The chapter also explains how different factors affect the road capacity. After identifying the various factors affecting the available road capacity, a causal loop diagram (CLD) is created to visually represent the causes leading to a change in the available road capacity and the effects on travel costs when the available road capacity changes.

  1. Roads at risk - traffic detours from debris flows in southern Norway

    NASA Astrophysics Data System (ADS)

    Meyer, N. K.; Schwanghart, W.; Korup, O.; Nadim, F.

    2014-10-01

    Globalization and interregional exchange of people, goods, and services has boosted the importance of and reliance on all kinds of transport networks. The linear structure of road networks is especially sensitive to natural hazards. In southern Norway, steep topography and extreme weather events promote frequent traffic disruption caused by debris flows. Topographic susceptibility and trigger frequency maps serve as input into a hazard appraisal at the scale of first-order catchments to quantify the impact of debris flows on the road network in terms of a failure likelihood of each link connecting two network vertices, e.g., road junctions. We compute total additional traffic loads as a function of traffic volume and excess distance, i.e. the extra length of an alternative path connecting two previously disrupted network vertices using a shortest-path algorithm. Our risk metric of link failure is the total additional annual traffic load expressed as vehicle kilometers because of debris-flow related road closures. We present two scenarios demonstrating the impact of debris flows on the road network, and quantify the associated path failure likelihood between major cities in southern Norway. The scenarios indicate that major routes crossing the central and northwestern part of the study area are associated with high link failure risk. Yet options for detours on major routes are manifold, and incur only little additional costs provided that drivers are sufficiently well informed about road closures. Our risk estimates may be of importance to road network managers and transport companies relying of speedy delivery of services and goods.

  2. Roads at risk: traffic detours from debris flows in southern Norway

    NASA Astrophysics Data System (ADS)

    Meyer, N. K.; Schwanghart, W.; Korup, O.; Nadim, F.

    2015-05-01

    Globalisation and interregional exchange of people, goods, and services has boosted the importance of and reliance on all kinds of transport networks. The linear structure of road networks is especially sensitive to natural hazards. In southern Norway, steep topography and extreme weather events promote frequent traffic disruption caused by debris flows. Topographic susceptibility and trigger frequency maps serve as input into a hazard appraisal at the scale of first-order catchments to quantify the impact of debris flows on the road network in terms of a failure likelihood of each link connecting two network vertices, e.g. road junctions. We compute total additional traffic loads as a function of traffic volume and excess distance, i.e. the extra length of an alternative path connecting two previously disrupted network vertices using a shortest-path algorithm. Our risk metric of link failure is the total additional annual traffic load, expressed as vehicle kilometres, because of debris-flow-related road closures. We present two scenarios demonstrating the impact of debris flows on the road network and quantify the associated path-failure likelihood between major cities in southern Norway. The scenarios indicate that major routes crossing the central and north-western part of the study area are associated with high link-failure risk. Yet options for detours on major routes are manifold and incur only little additional costs provided that drivers are sufficiently well informed about road closures. Our risk estimates may be of importance to road network managers and transport companies relying on speedy delivery of services and goods.

  3. Road safety and simulation conferences: an interdisciplinary network for safer roads.

    PubMed

    Benedetto, Andrea; Calvi, Alessandro

    2014-06-01

    From 23rd to 25th October 2013 more than 300 researchers attended the 4th International Conference on Road Safety and Simulation (RSS 2013) in Rome, Italy, hosted by the Inter Universities Research Centre for Road Safety (CRISS) at the Department of Engineering of Roma Tre University. The aim of the Conference was to create a common interdisciplinary arena for researchers and professionals involved in road safety, facilitate the exchange of know-how and progress in the last advanced techniques, methods and tools and their applications to safety analysis. This special issue highlights some of the research presented at the Conference. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. The drive-wise project: driving simulator training increases real driving performance in healthy older drivers

    PubMed Central

    Casutt, Gianclaudio; Theill, Nathan; Martin, Mike; Keller, Martin; Jäncke, Lutz

    2014-01-01

    Background: Age-related cognitive decline is often associated with unsafe driving behavior. We hypothesized that 10 active training sessions in a driving simulator increase cognitive and on-road driving performance. In addition, driving simulator training should outperform cognitive training. Methods: Ninety-one healthy active drivers (62–87 years) were randomly assigned to one of three groups: (1) a driving simulator training group, (2) an attention training group (vigilance and selective attention), or (3) a control group. The main outcome variables were on-road driving and cognitive performance. Seventy-seven participants (85%) completed the training and were included in the analyses. Training gains were analyzed using a multiple regression analysis with planned orthogonal comparisons. Results: The driving simulator-training group showed an improvement in on-road driving performance compared to the attention-training group. In addition, both training groups increased cognitive performance compared to the control group. Conclusion: Driving simulator training offers the potential to enhance driving skills in older drivers. Compared to the attention training, the simulator training seems to be a more powerful program for increasing older drivers' safety on the road. PMID:24860497

  5. Resilience and efficiency in transportation networks

    PubMed Central

    Ganin, Alexander A.; Kitsak, Maksim; Marchese, Dayton; Keisler, Jeffrey M.; Seager, Thomas; Linkov, Igor

    2017-01-01

    Urban transportation systems are vulnerable to congestion, accidents, weather, special events, and other costly delays. Whereas typical policy responses prioritize reduction of delays under normal conditions to improve the efficiency of urban road systems, analytic support for investments that improve resilience (defined as system recovery from additional disruptions) is still scarce. In this effort, we represent paved roads as a transportation network by mapping intersections to nodes and road segments between the intersections to links. We built road networks for 40 of the urban areas defined by the U.S. Census Bureau. We developed and calibrated a model to evaluate traffic delays using link loads. The loads may be regarded as traffic-based centrality measures, estimating the number of individuals using corresponding road segments. Efficiency was estimated as the average annual delay per peak-period auto commuter, and modeled results were found to be close to observed data, with the notable exception of New York City. Resilience was estimated as the change in efficiency resulting from roadway disruptions and was found to vary between cities, with increased delays due to a 5% random loss of road linkages ranging from 9.5% in Los Angeles to 56.0% in San Francisco. The results demonstrate that many urban road systems that operate inefficiently under normal conditions are nevertheless resilient to disruption, whereas some more efficient cities are more fragile. The implication is that resilience, not just efficiency, should be considered explicitly in roadway project selection and justify investment opportunities related to disaster and other disruptions. PMID:29291243

  6. 36 CFR 1004.11 - Load, weight and size limits.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... apply to a vehicle operated on a Presidio Trust road. However, the Board may designate more restrictive limits when appropriate for traffic safety or protection of the road surface. The Board may require a.... 1004.11 Section 1004.11 Parks, Forests, and Public Property PRESIDIO TRUST VEHICLES AND TRAFFIC SAFETY...

  7. Validating pollutant load estimates from highways and roads.

    DOT National Transportation Integrated Search

    2015-12-31

    Rain and snowmelt that runs off of roadways carries pollutants. Pollutant event mean concentrations have been developed for various land uses to calculate annual pollutant loads. These were developed for total suspended solids, total phosphorus, and ...

  8. 13. DETAIL VIEW OF LOADING DOCK CANOPY, SHOWING TWIN TIMBER ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. DETAIL VIEW OF LOADING DOCK CANOPY, SHOWING TWIN TIMBER SUPPORT MEMBERS AND SUSPENDER BAR MOUNTING HARDWARE - Oakland Army Base, Transit Shed, East of Dunkirk Street & South of Burma Road, Oakland, Alameda County, CA

  9. 78. PIPING CHANNEL FOR FUEL LOADING, FUEL TOPPING, COMPRESSED AIR, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    78. PIPING CHANNEL FOR FUEL LOADING, FUEL TOPPING, COMPRESSED AIR, GASEOUS NITROGEN, AND HELIUM - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  10. Driving on urban roads: How we come to expect the 'correct' speed.

    PubMed

    Charlton, Samuel G; Starkey, Nicola J

    2017-11-01

    The subjective categories that drivers use to distinguish between different road types have been shown to influence the speeds they choose to drive but as yet we do not understand the road features that drivers use to make their discriminations. To better understand how drivers describe and categorise the roads they drive, 55 participants were recruited to drive a video of familiar urban roads in a driving simulator at the speed they would drive these roads in their own cars (using the accelerator and brake pedal in the driving simulator to adjust their speed). The participants were then asked to sort photos of the roads they had just driven into piles so that their driving would be the same on all roads in one pile but different to the other piles. Finally, they answered a series of questions about each road to indicate what speed they would drive, the safe speed for the road, their speed limit belief as well as providing ratings of comfort, difficulty and familiarity. Overall, drivers' categorisation of roads was informed by a number of factors including speed limit belief, road features and markings (including medians), road width, and presence of houses, driveways and footpaths. The participants' categories were congruent with what they thought the speed limits were, but not necessarily the actual speed limits. Mismatches between actual speed limits and speed limit beliefs appeared to result from category-level expectations about speed limits that took precedence over recent experience in the simulator. Roads that historically had a 50km/h speed limit but had been reduced to 40km/h were still regarded as 50km/h roads by the participants, underscoring the point that simply posting a sign with a lower speed limit is not enough to overcome drivers' expectations and habits associated with the visual appearance of a road. The findings provided insights into how drivers view and categorise roads, and identify specific areas that could be used to improve speed limit credibility. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Evaluation of Software Simulation of Road Weather Information System.

    DOT National Transportation Integrated Search

    2016-09-01

    A road weather information system (RWIS) is a combination of technologies that collects, transmits, models, and disseminates weather and road condition information. Sensors measure a range of weatherrelated conditions, including pavement temperatur...

  12. FTire and puzzling tyre physics: teacher, not student

    NASA Astrophysics Data System (ADS)

    Gipser, Michael

    2016-04-01

    By means of some instructive examples, the contribution shows how even complex phenomena and relations in tyre physics are better understood by using a physics-based tyre simulation model like FTire. In contrast to approximation-based phenomenological models, such an approach will give insight into, rather than requiring description of, the tyre's behaviour. Examples studied here comprise * predicted influence of wheel load, inflation pressure, camber angle, and slow rolling speed on parking torque, * predicted influence of inflation pressure on cornering stiffness and pneumatic trail, * relaxation length: ramping up and down slip angle and wheel load, * handling characteristic on very rough roads, * a strange phenomenon: cleats that 'attract' a tyre. Related to these studies, user-friendly simulation tools on the basis of FTire are introduced, which help in understanding the above-mentioned complex tyre properties. One of these tools, being valuable both in teaching and for vehicle/tyre dynamics experts in industry and research, allows the user to interactively modify, during a running simulation, tyre geometry, material data, and operating conditions. The impact of these variations both on tyre forces and moments as well as on internal tyre states can be directly seen in a running animation, and later analysed with a large variety of post-processing tools. Animations for all case studies are available for download on http://www.cosin.eu/animations. All registered trademarks used here are properties of their respective owners.

  13. A simulator study investigating how motorcyclists approach side-road hazards.

    PubMed

    Crundall, Elizabeth; Stedmon, Alex W; Saikayasit, Rossukorn; Crundall, David

    2013-03-01

    The most common form of motorcycle collision in the UK occurs when another road user fails to give way and pulls out from a side road in front of an oncoming motorcyclist. While research has considered these collisions from the car driver's perspective, no research to date has addressed how motorcyclists approach these potential hazards. This study conducted a detailed analysis of motorcyclist speed and road position on approach to side-roads in a simulated suburban setting. Novice, Experienced and Advanced riders rode two laps of a simulated route, encountering five side-roads on each lap. On the second lap, a car emerged from the first side-road in a typical 'looked but failed to see' accident scenario. Three Experienced riders and one Novice rider collided with the hazard. The Advanced rider group adopted the safest strategy when approaching side-roads, with a lane position closer to the centre of the road and slower speeds. In contrast, Experienced riders chose faster speeds, often over the speed limit, especially when approaching junctions with good visibility. Rider behaviour at non-hazard junctions was compared between laps, to investigate if riders modified their behaviour after experiencing the hazard. Whilst all riders were generally more cautious after the hazard, the Advanced riders modified their behaviour more than the other groups after the hazard vehicle had pulled out. The results suggest that advanced training can lead to safer riding styles that are not acquired by experience alone. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Field Testing and Load Rating Report, Bridge S-1090

    DTIC Science & Technology

    2008-05-01

    alignment to the road- way. The steel beams are rolled sections with cover plates welded to the bottom flange. Shear stud connectors were specified...live-load and superimposed dead-loads. In this case, there was no wearing surface on the bridge, and all dead-loads were applied to the...and live-load at Section G_Standard MCap 1021.9 kN-m Superimposed dead-load applied to composite model— wearing surface and railing DW 0.0 kN-m

  15. Contribution of atmospheric dry deposition to stormwater loads for PAHs and trace metals in a small and highly trafficked urban road catchment.

    PubMed

    Al Ali, Saja; Debade, Xavier; Chebbo, Ghassan; Béchet, Béatrice; Bonhomme, Céline

    2017-12-01

    A deep understanding of pollutant buildup and wash-off is essential for accurate urban stormwater quality modeling and for the development of stormwater management practices, knowing the potential adverse impacts of runoff pollution on receiving waters. In the context of quantifying the contribution of airborne pollutants to the contamination of stormwater runoff and assessing the need of developing an integrated AIR-WATER modeling chain, loads of polycyclic aromatic hydrocarbons (PAHs) and metal trace elements (MTEs) are calculated in atmospheric dry deposits, stormwater runoff, and surface dust stock within a small yet highly trafficked urban road catchment (~ 30,000 vehicles per day) near Paris. Despite the important traffic load and according to the current definition of "atmospheric" source, atmospheric deposition did not account for more than 10% of the PAHs and trace metal loads in stormwater samples for the majority of the events, based on the ratio of deposition to stormwater. This result shows that atmospheric deposition is not a major source of pollutants in stormwater, and thus, linking the air and water compartment in a modeling chain to have more accurate estimates of pollutant loads in stormwater runoff might not be relevant. Comparison of road dust with water samples demonstrates that only the fine fraction of the available stock is eroded during a rainfall event. Even if the atmosphere mostly generates fine particles, the existence of other sources of fine particles to stormwater runoff is highlighted.

  16. Estimation of Road Loads and Vibration Transmissibility of Torsion Bar Suspension System in a Tracked Vehicle

    NASA Astrophysics Data System (ADS)

    Gagneza, G. P. S.; Chandramohan, Sujatha

    2018-05-01

    Designing the suspension system of a tracked combat vehicle (CV) is really challenging as it has to satisfy conflicting requirements of good ride comfort, vehicle handling and stability characteristics. Many studies in this field have been reported in literature and it has been found that torsion bars satisfy the designer's conflicting requirements of good ride and handling and thus have reserved a place for themselves as the most widely used suspension system for military track vehicles. Therefore, it is imperative to evaluate the effectiveness of the torsion bar under dynamic conditions of undulating terrain and validating the same by correlating it with computer simulation results. Thus in the present work, the dynamic simulation of a 2N + 4 degrees of freedom (DOF) mathematical model has been carried out using MATLAB Simulink and the vibration levels were also measured experimentally on a 12 wheel stationed high mobility military tracked infantry combat vehicle (ICV BMP-II) traversing different terrain, that is, Aberdeen proving ground (APG) and Sinusoidal, at a constant vehicle speed. The dynamic force transmitted to the hull CG through the 12 torsion bar suspension systems was computed to be around 26,700 N and found to match the measured values. The vibration isolation of the torsion bar in bounce was found to be effective, with a transmissibility from the road wheel to the hull of about 0.6.

  17. Issues of using Longer Heavier Vehicles on Roads

    NASA Astrophysics Data System (ADS)

    Matuszkova, R.; Heczko, M.; Cepil, J.; Radimsky, M.

    2018-03-01

    Many logistics companies aim to save on freight costs. Recently, not only on Czech roads and on motorways, longer and heavier vehicles that exceed dimensions’ limits appeared. For these vehicles, it is necessary to apply for a special permit, which is, however, much more liberal than the permit for oversized and overweight load transport. This paper informs about checking routes of these vehicles by swept path analysis and finding locations on roads that can generate both safety risks and traffic fluency problems.

  18. Research of cost aspects of cement pavements construction

    NASA Astrophysics Data System (ADS)

    Bezuglyi, Artem; Illiash, Sergii; Tymoshchuk, Oleksandr

    2017-09-01

    The tendency to increasing traffic volume on public roads and to increased axle loads of vehicles makes the road scientists to develop scientifically justified methods for preserving the existing and developing the new transport network of Ukraine. One of the options for solving such issues is the construction of roads with rigid (cement concrete) pavement. However, any solution must be justified considering technical and economic components. This paper presents the results of the research of cost aspects of cement pavements construction.

  19. Road Map for Development of Crystal-Tolerant High Level Waste Glasses

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Matyas, Josef; Vienna, John D.; Peeler, David

    This road map guides the research and development for formulation and processing of crystal-tolerant glasses, identifying near- and long-term activities that need to be completed over the period from 2014 to 2019. The primary objective is to maximize waste loading for Hanford waste glasses without jeopardizing melter operation by crystal accumulation in the melter or melter discharge riser. The potential applicability to the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF) is also addressed in this road map.

  20. Road characteristics and driver fatigue: a simulator study.

    PubMed

    Oron-Gilad, Tal; Ronen, Adi

    2007-09-01

    Two experiments examined the influence of road characteristics on driver fatigue in a prolonged simulator drive. In experiment one, ten military truck drivers drove a mixed route, with straight, winding, and straight highway segments. In experiment two, 16 additional drivers drove either a straight, a winding, or a mixed route. Fatigue symptoms were assessed using performance, subjective, and psychophysiological measures (HRV). We hypothesized that drivers adopt different fatigue-coping strategies relative to the demands of the drive. Thus, on straight roads drivers are more likely to loosen their driving demands by either increasing their driving speed and/or not maintaining the lane position, as the road is tolerant to both strategies, whereas on winding roads, drivers are more likely to increase their speed but not their lane positioning. Our results confirm that decremental changes in driving performance varied among road types. In the straight road components, we found decrements in the quality of lane maintaining (experiment one) and steering quality (experiments one and two) and longitudinal speed (experiment two). In the winding road, we found that drivers increased their driving speed over time (experiments one and two).

  1. Deposition of motor vehicle emissions and winter maintenance along roadside assessed by snow analyses.

    PubMed

    Hautala, E L; Rekilä, R; Tarhanen, J; Ruuskanen, J

    1995-01-01

    A vertical snow-sampling method, where a sample was taken throughout the snowpack, was used to estimate the pollutant load on a roadside where average daily traffic density was about 9100 motor vehicles. The snow samples were collected at two sites, forest and open field, at two distances of 10 and 30 m from the road. The concentrations of inorganic anions (Cl(-), NO(-)(3), SO(2-)(4)), total N, polycyclic aromatic hydrocarbons (PAHs) and polychlorinated phenols (PCPhs) were analysed. The results suggest that on roadsides there is a deposition caused by road traffic emissions and winter maintenance which exceeds normal background deposition. Inorganic anions mainly in particle form, originating from winter maintenance, are deposited near the road. PAHs with low molecular weight (

  2. Modeling flash floods in southern France for road management purposes

    NASA Astrophysics Data System (ADS)

    Vincendon, Béatrice; Édouard, Simon; Dewaele, Hélène; Ducrocq, Véronique; Lespinas, Franck; Delrieu, Guy; Anquetin, Sandrine

    2016-10-01

    Flash-floods are among the most devastating hazards in the Mediterranean. A major subset of damage and casualties caused by flooding is related to road submersion. Distributed hydrological nowcasting can be used for road flooding monitoring. This requires rainfall-runoff simulations at a high space and time resolution. Distributed hydrological models, such as the ISBA-TOP coupled system used in this study, are designed to simulate discharges for any cross-section of a river but they are generally calibrated for certain outlets and give deteriorated results for the sub-catchment outlets. The paper first analyses ISBA-TOP discharge simulations in the French Mediterranean region for target points different from the outlets used for calibration. The sensitivity of the model to its governing factors is examined to highlight the validity of results obtained for ungauged river sections compared with those obtained for the main gauged outlets. The use of improved model inputs is found beneficial for sub-catchments simulation. The calibration procedure however provides the parameters' values for the main outlets only and these choices influence the simulations for ungauged catchments or sub-catchments. As a result, a new version of ISBA-TOP system without any parameter to calibrate is used to produce diagnostics relevant for quantifying the risk of road submersion. A first diagnostic is the simulated runoff spatial distribution, it provides a useful information about areas with a high risk of submersion. Then an indicator of the flood severity is given by simulated discharges presented with respect to return periods. The latter has to be used together with information about the vulnerability of road-river cross-sections.

  3. Grain Size Distribution and Health Risk Assessment of Metals in Outdoor Dust in Chengdu, Southwestern China.

    PubMed

    Chen, Mengqin; Pi, Lu; Luo, Yan; Geng, Meng; Hu, Wenli; Li, Zhi; Su, Shijun; Gan, Zhiwei; Ding, Sanglan

    2016-04-01

    A total of 27 outdoor dust samples from roads, parks, and high spots were collected and analyzed to investigate the contamination of 11 metals (Cr, Mn, Co, Ni, Cu, Zn, As, Sr, Cd, Sb, and Pb) in Chengdu, China. The results showed that the samples from the high spots exhibited the highest heavy metal level compared with those from the roads and the parks, except for Ni, Cu, and Pb. The dust was classified into five grain size fractions. The mean loads of each grain size fraction of 11 determined metals displayed similar distribution, and the contribution of median size (63-125, 125-250, 250-500 μm) fractions accounted for more than 70% of overall heavy metal loads. The health risk posed by the determined metals to human via dust ingestion, dermal contact, and inhalation was investigated. Oral and respiratory bioaccessible parts of the metals in dust were extracted using simulated stomach solution and composite lung serum. The mean bioaccessibilities of 11 investigated metals in the gastric solution were much higher than those in the composite lung serum, especially Zn, Cd, and Pb. Ingestion was the most important exposure pathway with percentage greater than 70% for both children and adults. Risk evaluation results illustrated that children in Chengdu might suffer noncarcinogenic risk when exposed to outdoor dust. Given that the cancer risk values of Pb and Cr larger than 1 × 10(-4), potential carcinogenic risk might occur for Chengdu residents through outdoor dust intake.

  4. Protection of Buried Pipe under Repeated Loading by Geocell Reinforcement

    NASA Astrophysics Data System (ADS)

    Khalaj, Omid; Joz Darabi, N.; Moghaddas Tafreshi, S. N.; Mašek, Bohuslav

    2017-12-01

    With increase in cities’ population and development of urbane life, passing buried pipelines near ground’s surface is inevitable in urban areas, roads, subways and highways. This paper presents the results of three-dimensional full scale model tests on high-density polyethylene (HDPE) pipe with diameter of 250 mm in geocell reinforced soil, subjected to repeated loading to simulate the vehicle loads. The effect of geocell’s pocket size (55*55 mm and 110*110 mm) and embedment depth of buried pipe (1.5 and 2 times pipe diameter) in improving the behaviour of buried pipes was investigated. The geocell’s height of 100 mm was used in all tests. The repeated load of 800 kPa was applied on circular loading plate with diameter of 250 mm. The results show that the pipe displacement, soil surface settlement and transferred pressure on the pipe’s crown has been influenced significantly upon the use of geocells. For example, the vertical diametric strain (VDS) and soil surface settlement (SSS), in a way that using a geocell with pocket size of 110*110 mm reduces by 27% and 43%, respectively, compared with the unreinforced one. Meanwhile, by increasing buried depth of pipe from 1.5D to 2D, the use of geocell of 110*110 mm delivers about 50% reduction in SSS and VDS, compared with the unreinforced soil.

  5. Contact stiffness considerations when simulating tyre/road noise

    NASA Astrophysics Data System (ADS)

    Winroth, Julia; Kropp, Wolfgang; Hoever, Carsten; Höstmad, Patrik

    2017-11-01

    Tyre/road simulation tools that can capture tyre vibrations, rolling resistance and noise generation are useful for understanding the complex processes that are involved and thereby promoting further development and optimisation. The most detailed tyre/road contact models use a spatial discretisation of the contact and assume an interfacial stiffness to account for the small-scale roughness within the elements. This interfacial stiffness has been found to have a significant impact on the simulated noise emissions but no thorough investigations of this sensitivity have been conducted. Three mechanisms are thought to be involved: The horn effect, the modal composition of the vibrational field of the tyre and the contact forces exciting the tyre vibrations. This study used a numerical tyre/road noise simulation tool based on physical relations to investigate these aspects. The model includes a detailed time-domain contact model with linear or non-linear contact springs that accounts for the effect of local tread deformation on smaller length scales. Results confirm that an increase in contact spring stiffness causes a significant increase of the simulated tyre/road noise. This is primarily caused by a corresponding increase in the contact forces, resulting in larger vibrational amplitudes. The horn effect and the modal composition are relatively unaffected and have minor effects on the radiated noise. A more detailed non-linear contact spring formulation with lower stiffness at small indentations results in a reduced high-frequency content in the contact forces and the simulated noise.

  6. Stability and failure analysis of steering tie-rod

    NASA Astrophysics Data System (ADS)

    Jiang, GongFeng; Zhang, YiLiang; Xu, XueDong; Ding, DaWei

    2008-11-01

    A new car in operation of only 8,000 km, because of malfunction, resulting in lost control and rammed into the edge of the road, and then the basic vehicle scrapped. According to the investigation of the site, it was found that the tie-rod of the car had been broken. For the subjective analysis of the accident and identifying the true causes of rupture of the tierod, a series of studies, from the angle of theory to experiment on the bended broken tie-rod, were conducted. The mechanical model was established; the stability of the defective tie-rod was simulated based on ANSYS software. Meanwhile, the process of the accident was simulated considering the effect of destabilization of different vehicle speed and direction of the impact. Simultaneously, macro graphic test, chemical composition analysis, microstructure analysis and SEM analysis of the fracture were implemented. The results showed that: 1) the toughness of the tie-rod is at a normal level, but there is some previous flaws. One quarter of the fracture surface has been cracked before the accident. However, there is no relationship between the flaw and this incident. The direct cause is the dynamic instability leading to the large deformation of impact loading. 2) The declining safety factor of the tie-rod greatly due to the previous flaws; the result of numerical simulation shows that previous flaw is the vital factor of structure instability, on the basis of the comparison of critical loads of the accident tie-rod and normal. The critical load can decrease by 51.3% when the initial defect increases 19.54% on the cross-sectional area, which meets the Theory of Koiter.

  7. High Modulus Asphalt Concrete with Dolomite Aggregates

    NASA Astrophysics Data System (ADS)

    Haritonovs, V.; Tihonovs, J.; Smirnovs, J.

    2015-11-01

    Dolomite is one of the most widely available sedimentary rocks in the territory of Latvia. Dolomite quarries contain about 1,000 million tons of this material. However, according to Latvian Road Specifications, this dolomite cannot be used for average and high intensity roads because of its low quality, mainly, its LA index (The Los Angeles abrasion test). Therefore, mostly the imported magmatic rocks (granite, diabase, gabbro, basalt) or imported dolomite are used, which makes asphalt expensive. However, practical experience shows that even with these high quality materials roads exhibit rutting, fatigue, and thermal cracks. The aim of the research is to develop a high performance asphalt concrete for base and binder courses using only locally available aggregates. In order to achieve resistance against deformations at a high ambient temperature, a hard grade binder was used. Workability, fatigue and thermal cracking resistance, as well as sufficient water resistance is achieved by low porosity (3-5%) and higher binder content compared to traditional asphalt mixtures. The design of the asphalt includes a combination of empirical and performance based tests, which in laboratory circumstances allow simulating traffic and environmental loads. High performance AC 16 base asphalt concrete was created using local dolomite aggregate with polymer modified (PMB 10/40-65) and hard grade (B20/30) bitumen. The mixtures were specified based on fundamental properties in accordance with EN 13108-1 standard.

  8. A model for investigating the influence of road surface texture and tyre tread pattern on rolling resistance

    NASA Astrophysics Data System (ADS)

    Hoever, Carsten; Kropp, Wolfgang

    2015-09-01

    The reduction of rolling resistance is essential for a more environmentally friendly road transportation sector. Both tyre and road design can be utilised to reduce rolling resistance. In both cases a reliable simulation tool is needed which is able to quantify the influence of design parameters on the rolling resistance of a tyre rolling on a specific road surface. In this work a previously developed tyre/road interaction model is extended to account for different tread patterns and for losses due to small-scale tread deformation. Calculated contact forces and tyre vibrations for tyre/road interaction under steady-state rolling are used to predict rolling losses in the tyre. Rolling resistance is calculated for a series of different tyre/road combinations. Results are compared with rolling resistance measurements. The agreement between simulations and measurements is generally very good. It is found that both the tyre structure and small-scale tread deformations contribute to the rolling losses. The small-scale contribution depends mainly on the road roughness profile. The mean profile depth of the road surface is identified to correlate very well with the rolling resistance. Additional calculations are performed for non-traditional rubberised road surfaces, however, with mixed results. This possibly indicates the existence of additional loss mechanisms for these surfaces.

  9. An experimental evaluation of potential scavenger effects on snake road mortality detections

    USGS Publications Warehouse

    Hubbard, Kaylan A.; Chalfoun, Anna D.

    2012-01-01

    As road networks expand and collisions between vehicles and wildlife become more common, accurately quantifying mortality rates for the taxa that are most impacted will be critical. Snakes are especially vulnerable to collisions with vehicles because of their physiology and behavior. Reptile road mortality is typically quantified using driving or walking surveys; however, scavengers can rapidly remove carcasses from the road and cause underestimation of mortality. Our objective was to determine the effect that scavengers might have had on our ability to accurately detect reptile road mortality during over 150 h and 4,000 km of driving surveys through arid shrublands in southwest Wyoming, which resulted in only two observations of mortality. We developed unique simulated snake carcasses out of Burbot (Lota lota), a locally invasive fish species, and examined removal rates across three different road types at three study sites. Carcass size was not a significant predictor of time of removal, and carcass removal was comparable during the daytime and nighttime hours. However, removal of simulated carcasses was higher on paved roads than unpaved or two-track roads at all study sites, with an average of 75% of the carcasses missing within 60 h compared to 34% and 31%, respectively. Scavengers may therefore negatively impact the ability of researchers to accurately detect herpetofaunal road mortality, especially for paved roads where road mortality is likely the most prevalent.

  10. Vehicle load-equalization system

    NASA Technical Reports Server (NTRS)

    Creasy, W. K.

    1976-01-01

    System uses cables and associated pulleys to form closed-loop suspension system for terrain compensation. Loop causes reactions at each of three wheels in response to loading at remaining wheel. Simplicity of design should be of interest to designers and manufacturers of construction equipment and off-road vehicles.

  11. 49 CFR 178.338-3 - Structural integrity.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... a decelerative force applied independently to each suspension assembly at the road surface using... the axial load resulting from an accelerative force applied to the horizontal pivot of the fifth wheel... or compressive stress generated by the axial load resulting from a decelerative force applied...

  12. 49 CFR 178.338-3 - Structural integrity.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... a decelerative force applied independently to each suspension assembly at the road surface using... the axial load resulting from an accelerative force applied to the horizontal pivot of the fifth wheel... or compressive stress generated by the axial load resulting from a decelerative force applied...

  13. 49 CFR 178.338-3 - Structural integrity.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... a decelerative force applied independently to each suspension assembly at the road surface using... the axial load resulting from an accelerative force applied to the horizontal pivot of the fifth wheel... or compressive stress generated by the axial load resulting from a decelerative force applied...

  14. Performance weight sensor using graded index optical fiber on static test with UTM

    NASA Astrophysics Data System (ADS)

    Khamimatul Ula, R.; Hanto, Dwi

    2017-05-01

    Overloading the vehicle on a highway cause the damage to roads, accidents and harm other road users. Required a weight sensor has a high sensitivity, resistant to corrosion and electromagnetic wave interference. Graded index optical fiber is a kind of fiber that has the potential to be used as a deformation sensor. This research aims to optimize the load sensor has been developed previously to detect a load on a ton scale. The weight sensor-based micro bending graded index fiber and LED as a light source capable of detecting a load from 0.7 to 1.93 tons with a standard deviation of 1.18 and 99.45% accuracy level in a static text using UTM. This sensor has been able to be used to detect heavy vehicles such as water truck wheels 6 and fuel trucks. The study will be further developed in order to detect the load to more than 8 tons.

  15. Traffic mortality and the role of minor roads.

    PubMed

    van Langevelde, Frank; van Dooremalen, Coby; Jaarsma, Catharinus F

    2009-01-01

    Roads have large impacts on wildlife, as they form one of the principal causes of mortality, and disturbance and fragmentation of habitat. These impacts are mainly studied and mitigated on major roads. It is, however, a widespread misconception that most animals are killed on major roads. In this paper, we argue that minor roads have a larger impact on wildlife with respect to habitat destruction, noise load and traffic mortality. We use data on traffic related deaths in badgers (Meles meles) in The Netherlands to illustrate that traffic mortality is higher on minor roads. We ask for a more extensive investigation of the environmental impacts of minor roads. Moreover, we argue that the success of mitigation on roads drastically increases when both major and minor roads are integrated in the planning of traffic flows. Therefore, we propose a strategy based on the concept of a "traffic-calmed area". Traffic-calmed areas create opportunities for wildlife by decreasing limitations for animal movement. We ask for further studies to estimate what size traffic-calmed areas should be to maintain minimum viable animal populations.

  16. Contribution of Road Grade to the Energy Use of Modern Automobiles Across Large Datasets of Real-World Drive Cycles: Preprint

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wood, E.; Burton, E.; Duran, A.

    Understanding the real-world power demand of modern automobiles is of critical importance to engineers using modeling and simulation to inform the intelligent design of increasingly efficient powertrains. Increased use of global positioning system (GPS) devices has made large scale data collection of vehicle speed (and associated power demand) a reality. While the availability of real-world GPS data has improved the industry's understanding of in-use vehicle power demand, relatively little attention has been paid to the incremental power requirements imposed by road grade. This analysis quantifies the incremental efficiency impacts of real-world road grade by appending high fidelity elevation profiles tomore » GPS speed traces and performing a large simulation study. Employing a large real-world dataset from the National Renewable Energy Laboratory's Transportation Secure Data Center, vehicle powertrain simulations are performed with and without road grade under five vehicle models. Aggregate results of this study suggest that road grade could be responsible for 1% to 3% of fuel use in light-duty automobiles.« less

  17. A multimodal assessment of driving performance in HIV infection.

    PubMed

    Marcotte, T D; Wolfson, T; Rosenthal, T J; Heaton, R K; Gonzalez, R; Ellis, R J; Grant, I

    2004-10-26

    To examine if HIV-seropositive (HIV+) individuals are at risk for impaired driving. Sixty licensed drivers (40 HIV+, 20 HIV-) completed a neuropsychological (NP) test battery and driving assessments. Eleven HIV+ subjects were NP-impaired. Driving-related skills were assessed using 1) two driving simulations (examining accident avoidance and navigational abilities), 2) the Useful Field of View (UFOV) test, and 3) an on-road evaluation. HIV+ NP-impaired subjects had greater difficulty than cognitively intact subjects on all driving measures, whereas the HIV- and HIV+ NP-normal groups performed similarly. On the UFOV, the HIV+ NP-impaired group had worse performance on Visual Processing and Divided Attention tasks but not in overall risk classification. They also had a higher number of simulator accidents (1.3 vs 2.0; p = 0.03), were less efficient at completing the navigation task (3.2 vs 9.2 blocks; p = 0.001), and were more likely to fail the on-road evaluation (6 vs 36%; p = 0.02). Impairment in Executive Functioning was the strongest NP predictor of failing the on-road drive test. NP performance and both simulations independently contributed to a model predicting 48% of the variance in on-road performance. HIV+ NP-impaired individuals are at increased risk for on-road driving impairments, whereas HIV+ individuals with normal cognition are not at a significantly higher risk than HIV- subjects. Executive Functioning is most strongly associated with impaired on-road performance. Cognitive and simulator testing may each provide data in identifying driving-impaired individuals.

  18. Performance and driveline analyses of engine capacity in range extender engine hybrid vehicle

    NASA Astrophysics Data System (ADS)

    Praptijanto, Achmad; Santoso, Widodo Budi; Nur, Arifin; Wahono, Bambang; Putrasari, Yanuandri

    2017-01-01

    In this study, range extender engine designed should be able to meet the power needs of a power generator of hybrid electrical vehicle that has a minimum of 18 kW. Using this baseline model, the following range extenders will be compared between conventional SI piston engine (Baseline, BsL), engine capacity 1998 cm3, and efficiency-oriented SI piston with engine capacity 999 cm3 and 499 cm3 with 86 mm bore and stroke square gasoline engine in the performance, emission prediction of range extender engine, standard of charge by using engine and vehicle simulation software tools. In AVL Boost simulation software, range extender engine simulated from 1000 to 6000 rpm engine loads. The highest peak engine power brake reached up to 38 kW at 4500 rpm. On the other hand the highest torque achieved in 100 Nm at 3500 rpm. After that using AVL cruise simulation software, the model of range extended electric vehicle in series configuration with main components such as internal combustion engine, generator, electric motor, battery and the arthemis model rural road cycle was used to simulate the vehicle model. The simulation results show that engine with engine capacity 999 cm3 reported the economical performances of the engine and the emission and the control of engine cycle parameters.

  19. A scenario planning approach for disasters on Swiss road network

    NASA Astrophysics Data System (ADS)

    Mendes, G. A.; Axhausen, K. W.; Andrade, J. S.; Herrmann, H. J.

    2014-05-01

    We study a vehicular traffic scenario on Swiss roads in an emergency situation, calculating how sequentially roads block due to excessive traffic load until global collapse (gridlock) occurs and in this way displays the fragilities of the system. We used a database from Bundesamt für Raumentwicklung which contains length and maximum allowed speed of all roads in Switzerland. The present work could be interesting for government agencies in planning and managing for emergency logistics for a country or a big city. The model used to generate the flux on the Swiss road network was proposed by Mendes et al. [Physica A 391, 362 (2012)]. It is based on the conservation of the number of vehicles and allows for an easy and fast way to follow the formation of traffic jams in large systems. We also analyze the difference between a nonlinear and a linear model and the distribution of fluxes on the Swiss road.

  20. Correspondence between Simulator and On-Road Drive Performance: Implications for Assessment of Driving Safety.

    PubMed

    Aksan, Nazan; Hacker, Sarah D; Sager, Lauren; Dawson, Jeffrey; Anderson, Steven; Rizzo, Matthew

    2016-03-01

    Forty-two younger (Mean age = 35) and 37 older drivers (Mean age = 77) completed four similar simulated drives. In addition, 32 younger and 30 older drivers completed a standard on-road drive in an instrumented vehicle. Performance in the simulated drives was evaluated using both electronic drive data and video-review of errors. Safety errors during the on-road drive were evaluated by a certified driving instructor blind to simulator performance, using state Department of Transportation criteria. We examined the degree of convergence in performance across the two platforms on various driving tasks including lane change, lane keeping, speed control, stopping, turns, and overall performance. Differences based on age group indicated a pattern of strong relative validity for simulator measures. However, relative rank-order in specific metrics of performance suggested a pattern of moderate relative validity. The findings have implications for the use of simulators in assessments of driving safety as well as its use in training and/or rehabilitation settings.

  1. Correspondence between Simulator and On-Road Drive Performance: Implications for Assessment of Driving Safety

    PubMed Central

    Aksan, Nazan; Hacker, Sarah D.; Sager, Lauren; Dawson, Jeffrey; Anderson, Steven; Rizzo, Matthew

    2017-01-01

    Forty-two younger (Mean age = 35) and 37 older drivers (Mean age = 77) completed four similar simulated drives. In addition, 32 younger and 30 older drivers completed a standard on-road drive in an instrumented vehicle. Performance in the simulated drives was evaluated using both electronic drive data and video-review of errors. Safety errors during the on-road drive were evaluated by a certified driving instructor blind to simulator performance, using state Department of Transportation criteria. We examined the degree of convergence in performance across the two platforms on various driving tasks including lane change, lane keeping, speed control, stopping, turns, and overall performance. Differences based on age group indicated a pattern of strong relative validity for simulator measures. However, relative rank-order in specific metrics of performance suggested a pattern of moderate relative validity. The findings have implications for the use of simulators in assessments of driving safety as well as its use in training and/or rehabilitation settings. PMID:28649572

  2. Advanced Simulator for Combat, Transport Vehicles, Submarines, Vessels, Airplanes and Helicopters

    DTIC Science & Technology

    2004-10-01

    simulation experiments. 3.1 Road vehicles - lane change test In order to evaluate the driving dynamics and also the driving safety of road vehicles...8] L.D. Chen, Y. Papelis, G. Watson, D. Solis. NADS at the University of Iowa: A Tool for Driving Safety Research, In Proceedings of 1st Human

  3. Population and Activity of On-road Vehicles in MOVES2014 ...

    EPA Pesticide Factsheets

    This report describes the sources and derivation for on-road vehicle population and activity information and associated adjustments as stored in the MOVES2014 default databases. Motor Vehicle Emission Simulator, the MOVES2014 model, is a set of modeling tools for estimating emissions produced by on-road (cars, trucks, motorcycles, etc.) and nonroad (backhoes, lawnmowers, etc.) mobile sources. The national default activity information in MOVES2014 provides a reasonable basis for estimating national emissions. However, the uncertainties and variability in the default data contribute to the uncertainty in the resulting emission estimates. Properly characterizing emissions from the on-road vehicle subset requires a detailed understanding of the cars and trucks that make up the vehicle fleet and their patterns of operation. The MOVES model calculates emission inventories by multiplying emission rates by the appropriate emission-related activity, applying correction (adjustment) factors as needed to simulate specific situations, and then adding up the emissions from all sources (populations) and regions. This report describes the sources and derivation for on-road vehicle population and activity information and associated adjustments as stored in the MOVES2014 default databases. Motor Vehicle Emission Simulator, the MOVES2014 model, is a set of modeling tools for estimating emissions produced by on-road (cars, trucks, motorcycles, etc.) and nonroad (backhoes, law

  4. The development and clinical trial of a Driving Simulator for the handicapped.

    PubMed

    Ku, Jeonghun; Jang, Dongpyo; Ahn, Heebum; Lee, Jaemin; Kim, Jeong A; Lee, Bumseok; Kim, In Y; Kim, Sun I

    2002-01-01

    We developed a Virtual Reality Driving Simulator in order to safely evaluate and improve the driving ability of the handicapped. The Virtual Environment consists of 18 sections (e.g. a speed limited road, a strait road, a curved road, a left turn course, etc) and each section is linked naturally. For the interface of our driving simulator, an actual car was adapted for realism and then connected to a computer. We also equipped it with hand control driving devices especially adapted for the handicapped. A beam projector was used so that the subjects could see the virtual scene on a large screen which was set in front of them. The subjects selected for this trial were 10 normal drivers with valid driving licenses and 15 patients with thoracicor lumber cord injuries who had prior driving experience. For evaluation, 5 driving skills were measured including average speed, steering stability, centerline violations, traffic signal violations, and driving time in various road conditions such as strait and curved roads. The normal subjects manipulated the gas pedal and the brake with their feet while the patients manipulated a hand control with their hands. After they finished driving the whole course, the participants answered the questions such as "How realistic did the Virtual Reality Driving Simulator seeme to you?" and "How much was your fear reduced". The five driving skills measured between the two groups (normal vs. handicapped) did not show any significant differences (p > 0.05). And in the three kinds of road conditions (a speed limited road and roads with a sharp curve and left-hand turn), the average speed of the handicapped group was 45.6 Km, less than 61.2 Km (p<0.05) of the normal group. In all, 11 patients (73%) reported that their fear of driving was reduced. Furthermore, their average score on the degree of realism question was 51.5%.

  5. Sources of hydrocarbons in urban road dust: Identification, quantification and prediction.

    PubMed

    Mummullage, Sandya; Egodawatta, Prasanna; Ayoko, Godwin A; Goonetilleke, Ashantha

    2016-09-01

    Among urban stormwater pollutants, hydrocarbons are a significant environmental concern due to their toxicity and relatively stable chemical structure. This study focused on the identification of hydrocarbon contributing sources to urban road dust and approaches for the quantification of pollutant loads to enhance the design of source control measures. The study confirmed the validity of the use of mathematical techniques of principal component analysis (PCA) and hierarchical cluster analysis (HCA) for source identification and principal component analysis/absolute principal component scores (PCA/APCS) receptor model for pollutant load quantification. Study outcomes identified non-combusted lubrication oils, non-combusted diesel fuels and tyre and asphalt wear as the three most critical urban hydrocarbon sources. The site specific variabilities of contributions from sources were replicated using three mathematical models. The models employed predictor variables of daily traffic volume (DTV), road surface texture depth (TD), slope of the road section (SLP), effective population (EPOP) and effective impervious fraction (EIF), which can be considered as the five governing parameters of pollutant generation, deposition and redistribution. Models were developed such that they can be applicable in determining hydrocarbon contributions from urban sites enabling effective design of source control measures. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. On-Road Chemical Transformation as an Important Mechanism of NO2 Formation.

    PubMed

    Yang, Bo; Zhang, K Max; Xu, W David; Zhang, Shaojun; Batterman, Stuart; Baldauf, Richard W; Deshmukh, Parikshit; Snow, Richard; Wu, Ye; Zhang, Qiang; Li, Zhenhua; Wu, Xian

    2018-04-17

    Nitrogen dioxide (NO 2 ) not only is linked to adverse effects on the respiratory system but also contributes to the formation of ground-level ozone (O 3 ) and fine particulate matter (PM 2.5 ). Our curbside monitoring data analysis in Detroit, MI, and Atlanta, GA, strongly suggests that a large fraction of NO 2 is produced during the "tailpipe-to-road" stage. To substantiate this finding, we designed and carried out a field campaign to measure the same exhaust plumes at the tailpipe-level by a portable emissions measurement system (PEMS) and at the on-road level by an electric vehicle-based mobile platform. Furthermore, we employed a turbulent reacting flow model, CTAG, to simulate the on-road chemistry behind a single vehicle. We found that a three-reaction (NO-NO 2 -O 3 ) system can largely capture the rapid NO to NO 2 conversion (with time scale ≈ seconds) observed in the field studies. To distinguish the contributions from different mechanisms to near-road NO 2 , we clearly defined a set of NO 2 /NO x ratios at different plume evolution stages, namely tailpipe, on-road, curbside, near-road, and ambient background. Our findings from curbside monitoring, on-road experiments, and simulations imply the on-road oxidation of NO by ambient O 3 is a significant, but so far ignored, contributor to curbside and near-road NO 2 .

  7. Comparison of human driver dynamics in simulators with complex and simple visual displays and in an automobile on the road

    NASA Technical Reports Server (NTRS)

    Mcruer, D. T.; Klein, R. H.

    1975-01-01

    As part of a comprehensive program exploring driver/vehicle system response in lateral steering tasks, driver/vehicle system describing functions and other dynamic data have been gathered in several milieu. These include a simple fixed base simulator with an elementary roadway delineation only display; a fixed base statically operating automobile with a terrain model based, wide angle projection system display; and a full scale moving base automobile operating on the road. Dynamic data with the two fixed base simulators compared favorably, implying that the impoverished visual scene, lack of engine noise, and simplified steering wheel feel characteristics in the simple simulator did not induce significant driver dynamic behavior variations. The fixed base vs. moving base comparisons showed substantially greater crossover frequencies and phase margins on the road course.

  8. Characteristics of dynamic triaxial testing of asphalt mixtures

    NASA Astrophysics Data System (ADS)

    Ulloa Calderon, Alvaro

    Due to the increasing traffic loads and tire pressures, a serious detrimental impact has occurred on flexible pavements in the form of excessive permanent deformation once the critical combination of loading and environmental conditions are reached. This distress, also known as rutting, leads to an increase in road roughness and ultimately jeopardizes the road users' safety. The flow number (FN) simple performance test for asphalt mixtures was one of the final three tests selected for further evaluation from the twenty-four test/material properties initially examined under the NCHRP 9-19 project. Currently, no standard triaxial testing conditions in terms of the magnitude of the deviator and confining stresses have been specified. In addition, a repeated haversine axial compressive load pulse of 0.1 second and a rest period of 0.9 second are commonly used as part of the triaxial testing conditions. The overall objective of this research was to define the loading conditions that created by a moving truck load in the hot mixed asphalt (HMA) layer. The loading conditions were defined in terms of the triaxial stress levels and the corresponding loading time. Dynamic mechanistic analysis with circular stress distribution was used to closely simulate field loading conditions. Extensive mechanistic analyses of three different asphalt pavement structures subjected to moving traffic loads at various speeds and under braking and non-braking conditions were conducted using the 3D-Move model. Prediction equations for estimating the anticipated deviator and confining stresses along with the equivalent deviator stress pulse duration as a function of pavement temperature, vehicle speed, and asphalt mixture's stiffness have been developed. The magnitude of deviator stress, sigmad and confining stress, sigmac, were determined by converting the stress tensor computed in the HMA layer at 2" below pavement surface under a moving 18-wheel truck using the octahedral normal and shear stresses. In addition, the characteristics of the loading pulse were determined by best-fitting a haversine wave shape for the equivalent triaxial deviator stress pulse. The tandem axle was proven to generate the most critical combination of deviator and confining stresses for braking and non-braking conditions at 2 inches below the pavement surface. Thus, this study is focused on developing the stress state and pulse characteristics required to determine the critical conditions on HMA mixtures under the loading of the tandem axle. An increase of 40% was observed in the deviator stress when braking conditions are incorporated. A preliminary validation of the recommended magnitudes for the deviator and confining stresses on a field mixture from WesTrack showed consistent results between the flow number test results and field performance. Based on laboratory experiments, the critical conditions of different field mixtures from the WesTrack project and also lab produced samples at different air-voids levels were determined. The results indicate that the tertiary stage will occur under the FN test when a combination of a critical temperature and a given loading conditions for specific air voids content occurs.

  9. A case study demonstrating analysis of stormflows, concentrations, and loads of nutrients in highway runoff and swale discharge with the Stochastic Empirical Loading and Dilution Model (SELDM)

    USGS Publications Warehouse

    Granato, Gregory E.; Jones, Susan C.

    2015-01-01

    The case study is hypothetical, but was formulated by using actual data from selected monitoring sites in New England. Data representing streamflow and water-quality were collected at U.S. Geological Survey (USGS) streamgage 01208950 Sasco Brook near Southport, CT, which has a drainage area of 7.38 square miles. In this hypothetical case study a 4-lane highway would replace the current 2-lane road and would have a contributing area of 2.2 acres between the topographic basin divides. Concentrations of TN and TP in highway runoff were simulated with data from USGS highway-runoff monitoring station 423027071291301 along State Route 2 in Littleton Massachusetts. Results of a highway-runoff analysis are shown in relation to three hypothetical discharge criteria for TN and two hypothetical discharge criteria for TP. The risks for exceeding TN discharge criteria of 3, 5, and 8 mg/L for highway runoff are 7.4, 0.83, and 0.13 percent of 1,721 runoff events that may occur during a stochastic 30-year simulation. If a grassy swale is used to treat the runoff, the risks for TN exceedances are reduced to 3.2, 0.33 and 0.03 percent, respectively. The risks for exceeding TP discharge criteria of 0.1 and 0.5 mg/L for highway runoff are 49 and 1.2 percent, respectively. If a grassy swale is used to treat the runoff, the risks for TP exceedances are 57 and 0.8 percent, respectively. The risks for the 0.1 mg/L criterion increase because swales can be a source of TP if pavement concentrations are low. The risks for the 0.5 mg/L criterion decrease because the swale is effective for reducing high TP concentrations. Although the results are mixed for storm-event concentrations, the grassy swale effectively reduces annual loads. Annual loads from the swale are, on average, about 49 percent of highway loads for TN and 62 percent of highway loads of TP because the swale reduces high runoff concentrations and stormflow volumes. Analysis of upstream and downstream concentrations indicates that runoff from the site of interest does not have a substantial effect on instream stormflow concentrations in this example simulation.

  10. Disentangle the Causes of the Road Barrier Effect in Small Mammals through Genetic Patterns.

    PubMed

    Ascensão, Fernando; Mata, Cristina; Malo, Juan E; Ruiz-Capillas, Pablo; Silva, Catarina; Silva, André P; Santos-Reis, Margarida; Fernandes, Carlos

    2016-01-01

    Road barrier effect is among the foremost negative impacts of roads on wildlife. Knowledge of the factors responsible for the road barrier effect is crucial to understand and predict species' responses to roads, and to improve mitigation measures in the context of management and conservation. We built a set of hypothesis aiming to infer the most probable cause of road barrier effect (traffic effect or road surface avoidance), while controlling for the potentially confounding effects road width, traffic volume and road age. The wood mouse Apodemus sylvaticus was used as a model species of small and forest-dwelling mammals, which are more likely to be affected by gaps in cover such as those resulting from road construction. We confront genetic patterns from opposite and same roadsides from samples of three highways and used computer simulations to infer migration rates between opposite roadsides. Genetic patterns from 302 samples (ca. 100 per highway) suggest that the highway barrier effect for wood mouse is due to road surface avoidance. However, from the simulations we estimated a migration rate of about 5% between opposite roadsides, indicating that some limited gene flow across highways does occur. To reduce highway impact on population genetic diversity and structure, possible mitigation measures could include retrofitting of culverts and underpasses to increase their attractiveness and facilitate their use by wood mice and other species, and setting aside roadside strips without vegetation removal to facilitate establishment and dispersal of small mammals.

  11. Disentangle the Causes of the Road Barrier Effect in Small Mammals through Genetic Patterns

    PubMed Central

    Ascensão, Fernando; Mata, Cristina; Malo, Juan E.; Ruiz-Capillas, Pablo; Silva, Catarina; Silva, André P.; Santos-Reis, Margarida; Fernandes, Carlos

    2016-01-01

    Road barrier effect is among the foremost negative impacts of roads on wildlife. Knowledge of the factors responsible for the road barrier effect is crucial to understand and predict species’ responses to roads, and to improve mitigation measures in the context of management and conservation. We built a set of hypothesis aiming to infer the most probable cause of road barrier effect (traffic effect or road surface avoidance), while controlling for the potentially confounding effects road width, traffic volume and road age. The wood mouse Apodemus sylvaticus was used as a model species of small and forest-dwelling mammals, which are more likely to be affected by gaps in cover such as those resulting from road construction. We confront genetic patterns from opposite and same roadsides from samples of three highways and used computer simulations to infer migration rates between opposite roadsides. Genetic patterns from 302 samples (ca. 100 per highway) suggest that the highway barrier effect for wood mouse is due to road surface avoidance. However, from the simulations we estimated a migration rate of about 5% between opposite roadsides, indicating that some limited gene flow across highways does occur. To reduce highway impact on population genetic diversity and structure, possible mitigation measures could include retrofitting of culverts and underpasses to increase their attractiveness and facilitate their use by wood mice and other species, and setting aside roadside strips without vegetation removal to facilitate establishment and dispersal of small mammals. PMID:26978779

  12. The effect of increasing gravel cover on forest roads for reduced sediment delivery to stream crossings

    Treesearch

    Kristopher Brown; Kevin J. McGuire; W. Michael Aust; W. Cully Hession; C. Andrew Dolloff

    2014-01-01

    Direct sediment inputs from forest roads at stream crossings are a major concern for water quality and aquatic habitat. Legacy road–stream crossing approaches, or the section of road leading to the stream, may have poor water and grade control upon reopening, thus increasing the potential for negative impacts to water quality. Rainfall simulation experiments were...

  13. Tyre-road friction coefficient estimation based on tyre sensors and lateral tyre deflection: modelling, simulations and experiments

    NASA Astrophysics Data System (ADS)

    Hong, Sanghyun; Erdogan, Gurkan; Hedrick, Karl; Borrelli, Francesco

    2013-05-01

    The estimation of the tyre-road friction coefficient is fundamental for vehicle control systems. Tyre sensors enable the friction coefficient estimation based on signals extracted directly from tyres. This paper presents a tyre-road friction coefficient estimation algorithm based on tyre lateral deflection obtained from lateral acceleration. The lateral acceleration is measured by wireless three-dimensional accelerometers embedded inside the tyres. The proposed algorithm first determines the contact patch using a radial acceleration profile. Then, the portion of the lateral acceleration profile, only inside the tyre-road contact patch, is used to estimate the friction coefficient through a tyre brush model and a simple tyre model. The proposed strategy accounts for orientation-variation of accelerometer body frame during tyre rotation. The effectiveness and performance of the algorithm are demonstrated through finite element model simulations and experimental tests with small tyre slip angles on different road surface conditions.

  14. Effects of road infrastructure and traffic complexity in speed adaptation behaviour of distracted drivers.

    PubMed

    Oviedo-Trespalacios, Oscar; Haque, Md Mazharul; King, Mark; Washington, Simon

    2017-04-01

    The use of mobile phones while driving remains a major human factors issue in the transport system. A significant safety concern is that driving while distracted by a mobile phone potentially modifies the driving speed leading to conflicts with other road users and consequently increases crash risk. However, the lack of systematic knowledge of the mechanisms involved in speed adaptation of distracted drivers constrains the explanation and modelling of the extent of this phenomenon. The objective of this study was to investigate speed adaptation of distracted drivers under varying road infrastructure and traffic complexity conditions. The CARRS-Q Advanced Driving Simulator was used to test participants on a simulated road with different traffic conditions, such as free flow traffic along straight roads, driving in urbanized areas, and driving in heavy traffic along suburban roads. Thirty-two licensed young drivers drove the simulator under three phone conditions: baseline (no phone conversation), hands-free and handheld phone conversations. To understand the relationships between distraction, road infrastructure and traffic complexity, speed adaptation calculated as the deviation of driving speed from the posted speed limit was modelled using a decision tree. The identified groups of road infrastructure and traffic characteristics from the decision tree were then modelled with a Generalized Linear Mixed Model (GLMM) with repeated measures to develop inferences about speed adaptation behaviour of distracted drivers. The GLMM also included driver characteristics and secondary task demands as predictors of speed adaptation. Results indicated that complex road environments like urbanization, car-following situations along suburban roads, and curved road alignment significantly influenced speed adaptation behaviour. Distracted drivers selected a lower speed while driving along a curved road or during car-following situations, but speed adaptation was negligible in the presence of high visual cutter, indicating the prioritization of the driving task over the secondary task. Additionally, drivers who scored high on self-reported safe attitudes towards mobile phone usage, and who reported prior involvement in a road traffic crash, selected a lower driving speed in the distracted condition than in the baseline. The results aid in understanding how driving task demands influence speed adaptation of distracted drivers under various road infrastructure and traffic complexity conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Quantification of Road Network Vulnerability and Traffic Impacts to Regional Landslide Hazards.

    NASA Astrophysics Data System (ADS)

    Postance, Benjamin; Hillier, John; Dixon, Neil; Dijkstra, Tom

    2015-04-01

    Slope instability represents a prevalent hazard to transport networks. In the UK regional road networks are frequently disrupted by multiple slope failures triggered during intense precipitation events; primarily due to a degree of regional homogeneity of slope materials, geomorphology and weather conditions. It is of interest to examine how different locations and combinations of slope failure impact road networks, particularly in the context of projected climate change and a 40% increase in UK road demand by 2040. In this study an extensive number (>50 000) of multiple failure event scenarios are simulated within a dynamic micro simulation to assess traffic impacts during peak flow (7 - 10 AM). Possible failure locations are selected within the county of Gloucestershire (3150 km2) using historic failure sites and British Geological Survey GeoSure data. Initial investigations employ a multiple linear regression analyses to consider the severity of traffic impacts, as measured by time, in respect of spatial and topographical network characteristics including connectivity, density and capacity in proximity to failure sites; the network distance between disruptions in multiple failure scenarios is used to consider the effects of spatial clustering. The UK Department of Transport road travel demand and UKCP09 weather projection data to 2080 provide a suitable basis for traffic simulations and probabilistic slope stability assessments. Future work will thus focus on the development of a catastrophe risk model to simulate traffic impacts under various narratives of future travel demand and slope instability under climatic change. The results of this investigation shall contribute to the understanding of road network vulnerabilities and traffic impacts from climate driven slope hazards.

  16. Transport and fate of chloride from road salt within a mixed urban and agricultural watershed in Illinois (USA): assessing the influence of chloride application rates

    NASA Astrophysics Data System (ADS)

    Ludwikowski, Jessica J.; Peterson, Eric W.

    2018-06-01

    In a typical winter season, approximately 471,000 tons of road salt are deposited along roadways in Illinois, USA. An estimated 45% of the deposited road salt will infiltrate through the soils and into shallow aquifers. Transported through shallow aquifers, chloride associated with the road salts has the potential to reside within groundwater for years based on the pathway, the geologic material, and the recharge rate of the aquifer system. Utilizing MODFLOW and MT3D, simulations employing various road-salt application rates were conducted to assess the net accumulation of chloride and the residence times of chloride in an agriculture-dominated watershed that originates in an urban area. A positive-linear relationship was observed between the application rate of chloride and both the maximum chloride concentration and total mass accumulated within the watershed. Simulated annual recharge rates along impacted surfaces ranged from 1,000 to 10,000 mg/L. After 60 years of application, simulated chloride concentrations in groundwater ranged from 197 to 1,900 mg/L. For all application rates, chloride concentrations within the groundwater rose at an annual rate of >3 mg/L. While concentrations increase throughout the system, the majority of chloride accumulation occurs near the roads and the urban areas. Model simulations reveal a positive relationship between application rate and residence time of chloride (1,123-1,288 days based on application rate). The models indicate that continued accumulation of chloride in shallow aquifers can be expected, and methods that apply less chloride effectively need to be examined.

  17. Transport and fate of chloride from road salt within a mixed urban and agricultural watershed in Illinois (USA): assessing the influence of chloride application rates

    NASA Astrophysics Data System (ADS)

    Ludwikowski, Jessica J.; Peterson, Eric W.

    2018-01-01

    In a typical winter season, approximately 471,000 tons of road salt are deposited along roadways in Illinois, USA. An estimated 45% of the deposited road salt will infiltrate through the soils and into shallow aquifers. Transported through shallow aquifers, chloride associated with the road salts has the potential to reside within groundwater for years based on the pathway, the geologic material, and the recharge rate of the aquifer system. Utilizing MODFLOW and MT3D, simulations employing various road-salt application rates were conducted to assess the net accumulation of chloride and the residence times of chloride in an agriculture-dominated watershed that originates in an urban area. A positive-linear relationship was observed between the application rate of chloride and both the maximum chloride concentration and total mass accumulated within the watershed. Simulated annual recharge rates along impacted surfaces ranged from 1,000 to 10,000 mg/L. After 60 years of application, simulated chloride concentrations in groundwater ranged from 197 to 1,900 mg/L. For all application rates, chloride concentrations within the groundwater rose at an annual rate of >3 mg/L. While concentrations increase throughout the system, the majority of chloride accumulation occurs near the roads and the urban areas. Model simulations reveal a positive relationship between application rate and residence time of chloride (1,123-1,288 days based on application rate). The models indicate that continued accumulation of chloride in shallow aquifers can be expected, and methods that apply less chloride effectively need to be examined.

  18. Metals in European roadside soils and soil solution--a review.

    PubMed

    Werkenthin, Moritz; Kluge, Björn; Wessolek, Gerd

    2014-06-01

    This review provides a summary of studies analysing metal concentrations in soils and soil solution at European roadsides. The data collected during 27 studies covering a total of 64 sites across a number of European countries were summarised. Highest median values of Cr, Cu, Ni, Pb, and Zn were determined in the top soil layer at the first 5 m beside the road. Generally, the influence of traffic on soil contamination decreased with increasing soil depth and distance to the road. The concentration patterns of metals in soil solution were independent from concentrations in the soil matrix. At 10-m distance, elevated soil metal concentrations, low pH, and low percolation rates led to high solute concentrations. Directly beside the road, high percolation rates lead to high annual loadings although solute concentrations are comparatively low. These loadings might be problematic, especially in regions with acidic sandy soils and a high groundwater table. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Multilane Traffic Flow Modeling Using Cellular Automata Theory

    NASA Astrophysics Data System (ADS)

    Chechina, Antonina; Churbanova, Natalia; Trapeznikova, Marina

    2018-02-01

    The paper deals with the mathematical modeling of traffic flows on urban road networks using microscopic approach. The model is based on the cellular automata theory and presents a generalization of the Nagel-Schreckenberg model to a multilane case. The created program package allows to simulate traffic on various types of road fragments (T or X type intersection, strait road elements, etc.) and on road networks that consist of these elements. Besides that, it allows to predict the consequences of various decisions regarding road infrastructure changes, such as: number of lanes increasing/decreasing, putting new traffic lights into operation, building new roads, entrances/exits, road junctions.

  20. Interrater Reliability of the Power Mobility Road Test in the Virtual Reality-Based Simulator-2.

    PubMed

    Kamaraj, Deepan C; Dicianno, Brad E; Mahajan, Harshal P; Buhari, Alhaji M; Cooper, Rory A

    2016-07-01

    To assess interrater reliability of the Power Mobility Road Test (PMRT) when administered through the Virtual Reality-based SIMulator-version 2 (VRSIM-2). Within-subjects repeated-measures design. Participants interacted with VRSIM-2 through 2 display options (desktop monitor vs immersive virtual reality screens) using 2 control interfaces (roller system vs conventional movement-sensing joystick), providing 4 different driving scenarios (driving conditions 1-4). Participants performed 3 virtual driving sessions for each of the 2 display screens and 1 session through a real-world driving course (driving condition 5). The virtual PMRT was conducted in a simulated indoor office space, and an equivalent course was charted in an open space for the real-world assessment. After every change in driving condition, participants completed a self-reported workload assessment questionnaire, the Task Load Index, developed by the National Aeronautics and Space Administration. A convenience sample of electric-powered wheelchair (EPW) athletes (N=21) recruited at the 31st National Veterans Wheelchair Games. Not applicable. Total composite PMRT score. The PMRT had high interrater reliability (intraclass correlation coefficient [ICC]>.75) between the 2 raters in all 5 driving conditions. Post hoc analyses revealed that the reliability analyses had >80% power to detect high ICCs in driving conditions 1 and 4. The PMRT has high interrater reliability in conditions 1 and 4 and could be used to assess EPW driving performance virtually in VRSIM-2. However, further psychometric assessment is necessary to assess the feasibility of administering the PMRT using the different interfaces of VRSIM-2. Copyright © 2016 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

  1. A new approach to developing a fugitive road dust emission inventory and emission trend from 2006 to 2010 in the beijing metropolitan area, china.

    PubMed

    Fan, Shoubin; Tian, Gang; Cheng, Shuiyuan; Qin, Jianping

    2013-07-01

    The USEPA emission factor (AP-42) of fugitive road dust (FRD) is widely used in establishing emission inventories. However, road silt loading sampling for AP-42 is expensive, time consuming, and dangerous. Therefore, a new method for establishing emission inventories based on road dust-fall (DF) monitors is described. Between January 2006 and December 2010, DF was monitored at 40 sites (80 samples), and background dust fall (DF) was monitored at 14 sites in the Beijing metropolitan area. Also during this period, 58 samples of road silt loadings were taken and used in the AP-42 emission factor equation to calculate FRD with particulate matter ≤10 μm in diameter [FRD(PM)] emission from the roads. Simultaneous measurement of FRD(PM) emissions calculated by AP-42 and ΔDF (i.e., the difference between the DF and DF) measured using gauges showed that the FRD(PM) emission for road dust was proportional to the ΔDF ( = 0.92). The FRD(PM) emission (kg km × 30 d) was calculated using the monitored ΔDF (t km × 30 d) by the formulation FRD(PM) = 278.3 × ΔDF - 1151.2. The ΔDF showed a general decline from 2006 to 2010. In particular, there was a sharp decline in August, September, and October 2008 due to strict dust controls enforced during the 2008 Olympic Games. Although there was a small increase in ΔDF after the Games, by the end of 2010 values were still lower than those before the Games. Using the 2006 ΔDF value as a benchmark, ΔDF values declined by 24.7, 33.0, 38.3, and 31.4% in 2007, 2008, 2009, and 2010, respectively. Based on using AP-42 calculations from silt loading and traffic information in 2007, the FRD(PM) emission distribution in the Beijing metropolitan area was mapped, and there were 2.05 × 10 tons of FRD(PM) emitted in 2007. The FRD(PM) from 2006 to 2010 was calculated by the ΔDF values. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  2. Simulation of random road microprofile based on specified correlation function

    NASA Astrophysics Data System (ADS)

    Rykov, S. P.; Rykova, O. A.; Koval, V. S.; Vlasov, V. G.; Fedotov, K. V.

    2018-03-01

    The paper aims to develop a numerical simulation method and an algorithm for a random microprofile of special roads based on the specified correlation function. The paper used methods of correlation, spectrum and numerical analysis. It proves that the transfer function of the generating filter for known expressions of spectrum input and output filter characteristics can be calculated using a theorem on nonnegative and fractional rational factorization and integral transformation. The model of the random function equivalent of the real road surface microprofile enables us to assess springing system parameters and identify ranges of variations.

  3. The Application of a WEPP Technology to a Complex Watershed Analysis

    NASA Astrophysics Data System (ADS)

    Elliot, William; Miller, Ina Sue; Dobre, Mariana

    2017-04-01

    Forest restoration activities are essential in many forest stands, where previous management and fire suppression has resulted in stands with high density, diseased trees and excessive fuel loads. Trying to balance the watershed impacts of restoration activities such as thinning, selective harvesting, and prescribed fire against the significant impact of wildfire is challenging. The process is further aggravated by the necessity of a road network if management activities include timber removal. We propose to present an approach to a watershed analysis for a 3400-ha of fuel reduction project within an 18,0000-ha sensitive watershed in the Nez Perce National Forest in Northern Idaho, USA. The FlamMap fire spread model was first used to predict the distribution of potential fire severity on the landscape for the current fuel load, and for a landscape that had been treated by thinning and/or prescribed fire. FlamMap predicts the flame length by 30-m pixel as a function of fuel load and water content, wind speed, and slope steepness and aspect. The flame length distribution was then classified so that the distribution of burn severity (unburned, low, moderate and high severity) was similar to the distributions observed on recent wildfires in the Forest. The flame length classes determined for the current fuel loads were also used for the treated condition flame lengths, where predominantly unburned or low severity fire severities were predicted. The burn severity maps were uploaded to a web site that was developed to provide soil and management files reflecting burn severity and soil texture, formatted for the Geospatial interface to the Water Erosion Prediction Project (GeoWEPP). The study area was divided into 40 sub watersheds under 2.5 km2 each for GeoWEPP analysis. GeoWEPP was run for an undisturbed forest; for the burn severity following wildfire for the current and treated fuel loads; for prescribed fire, either broadcast or jack pot burn; and for thinning either by tractor or by skyline logging. The GeoWEPP erosion estimates by hillslope polygon were merged with the proposed treatment polygons to produce maps of erosion for each condition for each treatment polygon. Road network erosion was estimated using a new online GIS tool to estimate road segment length and steepness, and linking those topographic values to the WEPP model for erosion prediction by road segment. The results were summarized and compared to earlier estimates of sediment delivery using a locally-developed cumulative watershed effects analysis. The results were similar from both tools, in spite of using very different erosion estimation methods, and similar to regional observations of forest watershed sediment delivery ( 12.5 Mg/sq km). The study found that the erosion risk from wildfire was 5 times greater than sediment generated by forest management, justifying the proposed restoration activities to reduce fire risk. Sediment generated from the road network, however, was unacceptably high suggesting that methods improve road erosion prediction and/or to reduce road erosion are warranted.

  4. Sensitivity of subjective questionnaires to cognitive loading while driving with navigation aids: a pilot study.

    PubMed

    Smyth, Christopher C

    2007-05-01

    Developers of future forces are implementing automated aiding for driving tasks. In designing such systems, the effect of cognitive task interference on driving performance is important. The crew of such vehicles may have to occasionally perform communication and planning tasks while driving. Subjective questionnaires may aid researchers to parse out the sources of task interference in crew station designs. In this preliminary study, sixteen participants drove a vehicle simulator with automated road-turn cues (i.e., visual, audio, combined, or neither) along a course marked on a map display while replying to spoken test questions (i.e., repeating sentences, math and logical puzzles, route planning, or none) and reporting other vehicles in the scenario. Following each trial, a battery of subjective questionnaires was administered to determine the perceived effects of the loading on their cognitive functionality. Considering the performance, the participants drove significantly faster with the road-turn cues than with just the map. They recalled fewer vehicle sightings with the cognitive tests than without them. Questionnaire results showed that their reasoning was more straightforward, the quantity of information for understanding higher, and the trust greater with the combined cues than the map-only. They reported higher perceived workload with the cognitive tests. The capacity for maintaining situational awareness was reduced with the cognitive tests because of the increased division of attention and the increase in the instability, variability, and complexity of the demands. The association and intuitiveness of cognitive processing were lowest and the subjective stress highest for the route planning test. Finally, the confusability in reasoning was greater for the auditory cue with the route planning than the auditory cue without the cognitive tests. The subjective questionnaires are sensitive to the effects of the cognitive loading and, therefore, may be useful for guiding the development of automated aid designs.

  5. Loggers and Forest Fragmentation: Behavioral Models of Road Building in the Amazon Basin

    NASA Technical Reports Server (NTRS)

    Arima, Eugenio Y.; Walker, Robert T.; Perz, Stephen G.; Caldas, Marcellus

    2005-01-01

    Although a large literature now exists on the drivers of tropical deforestation, less is known about its spatial manifestation. This is a critical shortcoming in our knowledge base since the spatial pattern of land-cover change and forest fragmentation, in particular, strongly affect biodiversity. The purpose of this article is to consider emergent patterns of road networks, the initial proximate cause of fragmentation in tropical forest frontiers. Specifically, we address the road-building processes of loggers who are very active in the Amazon landscape. To this end, we develop an explanation of road expansions, using a positive approach combining a theoretical model of economic behavior with geographic information systems (GIs) software in order to mimic the spatial decisions of road builders. We simulate two types of road extensions commonly found in the Amazon basin in a region: showing the fishbone pattern of fragmentation. Although our simulation results are only partially successful, they call attention to the role of multiple agents in the landscape, the importance of legal and institutional constraints on economic behavior, and the power of GIs as a research tool.

  6. Predictive validity of driving-simulator assessments following traumatic brain injury: a preliminary study.

    PubMed

    Lew, Henry L; Poole, John H; Lee, Eun Ha; Jaffe, David L; Huang, Hsiu-Chen; Brodd, Edward

    2005-03-01

    To evaluate whether driving simulator and road test evaluations can predict long-term driving performance, we conducted a prospective study on 11 patients with moderate to severe traumatic brain injury. Sixteen healthy subjects were also tested to provide normative values on the simulator at baseline. At their initial evaluation (time-1), subjects' driving skills were measured during a 30-minute simulator trial using an automated 12-measure Simulator Performance Index (SPI), while a trained observer also rated their performance using a Driving Performance Inventory (DPI). In addition, patients were evaluated on the road by a certified driving evaluator. Ten months later (time-2), family members observed patients driving for at least 3 hours over 4 weeks and rated their driving performance using the DPI. At time-1, patients were significantly impaired on automated SPI measures of driving skill, including: speed and steering control, accidents, and vigilance to a divided-attention task. These simulator indices significantly predicted the following aspects of observed driving performance at time-2: handling of automobile controls, regulation of vehicle speed and direction, higher-order judgment and self-control, as well as a trend-level association with car accidents. Automated measures of simulator skill (SPI) were more sensitive and accurate than observational measures of simulator skill (DPI) in predicting actual driving performance. To our surprise, the road test results at time-1 showed no significant relation to driving performance at time-2. Simulator-based assessment of patients with brain injuries can provide ecologically valid measures that, in some cases, may be more sensitive than a traditional road test as predictors of long-term driving performance in the community.

  7. Erosion and sediment delivery following removal of forest roads

    USGS Publications Warehouse

    Madej, Mary Ann

    2001-01-01

    Erosion control treatments were applied to abandoned logging roads in California, with the goal of reducing road-related sediment input to streams and restoring natural hydrologic patterns on the landscape. Treatment of stream crossings involved excavating culverts and associated road fill and reshaping streambanks. A variety of techniques were applied to road benches, which included decompacting the road surface, placing unstable road fill in more stable locations, and re-establishing natural surface drainage patterns. Following treatment and a 12-year recurrence-interval storm, some road reaches and excavated stream crossings showed evidence of mass movement failures, gullying, bank erosion and channel incision. Post-treatment erosion from excavated stream crossings was related to two variables: a surrogate for stream power (drainage area × channel gradient) and the volume of fill excavated from the channel. Post-treatment erosion on road reaches was related to four explanatory variables: method of treatment, hillslope position (upper, mid-slope or lower), date of treatment, and an interaction term (hillslope position × method of treatment). Sediment delivery from treated roads in upper, middle and lower hillslope positions was 10, 135 and 550 m3 of sediment per kilometre of treated roads, respectively. In contrast, inventories of almost 500 km of forest roads in adjacent catchments indicate that untreated roads produced 1500 to 4700 m3 of sediment per kilometre of road length. Erosion from 300 km of treated roads contributed less than 2 per cent of the total sediment load of Redwood Creek during the period 1978 to 1998. Although road removal treatments do not completely eliminate erosion associated with forest roads, they do substantially reduce sediment yields from abandoned logging roads.

  8. Distribution of the concentration of heavy metals associated with the sediment particles accumulated on road surfaces.

    PubMed

    Zafra, C A; Temprano, J; Tejero, I

    2011-07-01

    The heavy metal pollution caused by road run-off water constitutes a problem in urban areas. The metallic load associated with road sediment must be determined in order to study its impact in drainage systems and receiving waters, and to perfect the design of prevention systems. This paper presents data regarding the sediment collected on road surfaces in the city of Torrelavega (northern Spain) during a period of 65 days (132 samples). Two sample types were collected: vacuum-dried samples and those swept up following vacuuming. The sediment loading (g m(-2)), particle size distribution (63-2800 microm) and heavy metal concentrations were determined. The data showed that the concentration of heavy metals tends to increase with the reduction in the particle diameter (exponential tendency). The concentrations ofPb, Zn, Cu, Cr, Ni, Cd, Fe, Mn and Co in the size fraction <63 microm were 350, 630, 124, 57, 56, 38, 3231, 374 and 51 mg kg(-1), respectively (average traffic density: 3800 vehicles day(-1)). By increasing the residence time of the sediment, the concentration increases, whereas the ratio of the concentration between the different size fractions decreases. The concentration across the road diminishes when the distance between the roadway and the sampling siteincreases; when the distance increases, the ratio between size fractions for heavy metal concentrations increases. Finally, the main sources of heavy metals are the particles detached by braking (brake pads) and tyre wear (rubber), and are associated with particle sizes <125 microm.

  9. Effectiveness of a Coral-Derived Surfacing Material for Reducing Sediment Production on Unpaved Roads, Schoffield Barracks, Oahu, Hawaii

    NASA Astrophysics Data System (ADS)

    Ziegler, Alan D.; Sutherland, Ross A.

    2006-01-01

    This study evaluated the effectiveness of two application rates of a coral-derived surfacing material for both traffic and nontraffic road conditions using simulated rainfall (110-120 mm h-1 for 30-90 min) on 0.75-m (wide) × 5.0-m (long) plots of similar slope (roughly 0.1 m m-1). The coral is a locally available material that has been applied to unpaved roads surfaces on Schoffield Barracks, Oahu, Hawaii (USA), where this experiment was conducted. The simulations show that compared with a bare control plot, the coral-based surface application rates of 80 and 160 kg m-2 (equivalent to only 10- and 20-mm thicknesses) reduced road sediment production by 75% and 95%, respectively, for nontraffic conditions. However, after two passes of the research vehicle during wet conditions, sediment production rates for the two coral treatments were not significantly different from those on the bare road plots. The overall effectiveness of the coral-derived surfacing material is unsatisfactory, primarily because the on-road surface thickness associated with the application rates tested was too small. These rates were selected to bracket those applied to training roads in the study area. Furthermore, the composition of the coral-based material does not facilitate the development of a sealed, erosion-resistant surface. When applied at the low rates tested, the coral material breaks down under normal traffic conditions, thereby losing its ability to counter shearing forces exerted by overland flow on long hillslopes where erosion measures are most needed. These simulations, combined with observations on roads in the study area, indicate that this material is not an appropriate road surfacing material for the site—at least for the low application rates examined. These results are preliminary; extended testing of higher applications rates at the hillslope scale under natural climate and traffic conditions is needed to better judge the effectiveness of this material over time.

  10. Effectiveness of a coral-derived surfacing material for reducing sediment production on unpaved roads, Schoffield barracks, Oahu, Hawaii.

    PubMed

    Ziegler, Alan D; Sutherland, Ross A

    2006-01-01

    This study evaluated the effectiveness of two application rates of a coral-derived surfacing material for both traffic and nontraffic road conditions using simulated rainfall (110-120 mm h(-1) for 30-90 min) on 0.75-m (wide) x 5.0-m (long) plots of similar slope (roughly 0.1 m m(-1)). The coral is a locally available material that has been applied to unpaved roads surfaces on Schoffield Barracks, Oahu, Hawaii (USA), where this experiment was conducted. The simulations show that compared with a bare control plot, the coral-based surface application rates of 80 and 160 kg m(-2) (equivalent to only 10- and 20-mm thicknesses) reduced road sediment production by 75% and 95%, respectively, for nontraffic conditions. However, after two passes of the research vehicle during wet conditions, sediment production rates for the two coral treatments were not significantly different from those on the bare road plots. The overall effectiveness of the coral-derived surfacing material is unsatisfactory, primarily because the on-road surface thickness associated with the application rates tested was too small. These rates were selected to bracket those applied to training roads in the study area. Furthermore, the composition of the coral-based material does not facilitate the development of a sealed, erosion-resistant surface. When applied at the low rates tested, the coral material breaks down under normal traffic conditions, thereby losing its ability to counter shearing forces exerted by overland flow on long hillslopes where erosion measures are most needed. These simulations, combined with observations on roads in the study area, indicate that this material is not an appropriate road surfacing material for the site-at least for the low application rates examined. These results are preliminary; extended testing of higher applications rates at the hillslope scale under natural climate and traffic conditions is needed to better judge the effectiveness of this material over time.

  11. Risk assessment on an Argentinean road with a dynamic traffic simulator

    NASA Astrophysics Data System (ADS)

    Voumard, Jérémie; Baumann, Valérie; Jaboyedoff, Michel; Derron, Marc-Henri; Penna, Ivanna

    2014-05-01

    The National Route 7 in Argentina is one of the most important corridors crossing the Andean Cordillera. It concentrates most of the traffic related to the Southern Common Market (MERCOSUR), it also connects Mendoza city (the fourth most populated in Argentina) with Santiago de Chile (the Chile capital city), and is used by tourists to access to the Aconcagua National park, Puente del Inca natural monument, skiing resorts, and to local displacements for the villages along the Mendoza valley. The road crosses the Andes through the Mendoza river valley at an elevation between 2'000 and 3'000 m. The traffic (2500 vehicles/day) is composed of motorcycles, cars and pickup trucks, trucks without trailer, buses, and semi-trailer trucks. Debris flows developed along tributaries of the Mendoza River, and due to remobilization of talus materials, impact frequently the road, causing traffic disruptions, bridges damages, etc. Rock falls detached from highly fractured outcrops also impact frequently the road, causing sometimes casualties. The aim of this study is to evaluate risk along sections of the National Road 7 develop along the Mendoza river, using a dynamic traffic simulator based on MATLAB© routine. The dynamic traffic simulator developed for natural hazards events on roads consider different scenarios based on traffic speeds, vehicle types, interactions types, road properties and natural processes. Here we show that vehicle types and traffic variations may influence the risk estimation. The analyzed risk on several critical sections of the National Route 7 demonstrates that risk may significantly increase: 1) on sinuous sections, steep sections and because of road conditions changes (exit of tunnel, bridges, road width, etc.) because of decreasing vehicle speed, particularly with semi-trailer trucks; 2) when an event, such a debris flow, occurs and generates a vehicle tailback increasing their duration presence in the risk area.

  12. 13. Photograph of a photograph in possession of the Watervliet ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. Photograph of a photograph in possession of the Watervliet Arsenal Museum, New York. THE FIRST 16' BREECH LOADING RIFLE PRODUCED BY THE ARSENAL SHOWN WITH THE GUN SHOP'S MECHANICS AND FOREMAN IN FRONT OF THE NORTH WING OF THE SEACOAST GUN SHOP AND THE FIELD AND SIEGE GUN SHOP. TAKEN IN 1901. - Watervliet Arsenal, Building No. 110, Hagner Road between Schull & Whittemore Roads, Watervliet, Albany County, NY

  13. Improving the Military Household Goods Movement Program

    DTIC Science & Technology

    1989-06-01

    They include the central franchise firms, local agencies, over-the-road vehicles and owner-operators [Ref. 37: p. 3-1]. However, the central franchise ...corporate logo may appear on the local agency and over-the-road vehicles. The central franchise firms are used for central dispatch and proper traffic...outbound and inbound moves which are normally dispatched and controlled :he central franchise firm. The last group. the owner-operators, will load, haul

  14. Fate of hydrocarbon pollutants in source and non-source control sustainable drainage systems.

    PubMed

    Roinas, Georgios; Mant, Cath; Williams, John B

    2014-01-01

    Sustainable drainage (SuDs) is an established method for managing runoff from developments, and source control is part of accepted design philosophy. However, there are limited studies into the contribution source control makes to pollutant removal, especially for roads. This study examines organic pollutants, total petroleum hydrocarbons (TPH) and polycyclic aromatic hydrocarbons (PAHs), in paired source and non-source control full-scale SuDs systems. Sites were selected to cover local roads, trunk roads and housing developments, with a range of SuDs, including porous asphalt, swales, detention basins and ponds. Soil and water samples were taken bi-monthly over 12 months to assess pollutant loads. Results show first flush patterns in storm events for solids, but not for TPH. The patterns of removal for specific PAHs were also different, reflecting varying physico-chemical properties. The potential of trunk roads for pollution was illustrated by peak runoff for TPH of > 17,000 μg/l. Overall there was no significant difference between pollutant loads from source and non-source control systems, but the dynamic nature of runoff means that longer-term data are required. The outcomes of this project will increase understanding of organic pollutants behaviour in SuDs. This will provide design guidance about the most appropriate systems for treating these pollutants.

  15. Characterizing near-road air pollution using local-scale emission and dispersion models and validation against in-situ measurements

    NASA Astrophysics Data System (ADS)

    Wang, An; Fallah-Shorshani, Masoud; Xu, Junshi; Hatzopoulou, Marianne

    2016-10-01

    Near-road concentrations of nitrogen dioxide (NO2), a known marker of traffic-related air pollution, were simulated along a busy urban corridor in Montreal, Quebec using a combination of microscopic traffic simulation, instantaneous emission modeling, and air pollution dispersion. In order to calibrate and validate the model, a data collection campaign was designed. For this purpose, measurements of NO2 were conducted mid-block along four segments of the corridor throughout a four-week campaign conducted between March and April 2015. The four segments were chosen to be consecutive and yet exhibiting variability in road configuration and built environment characteristics. Roadside NO2 measurements were also paired with on-site and fixed-station meteorological data. In addition, traffic volumes, composition, and routing decisions were collected using video-cameras located at upstream and downstream intersections. Dispersion of simulated emissions was conducted for eight time slots and under a range of meteorological conditions using three different models with vastly different dispersion algorithms (OSPM, CALINE 4, and SIRANE). The three models exhibited poor correlation with near-road NO2 concentrations and were better able to simulate average concentrations occurring along the roadways rather than the range of concentrations measured under diverse meteorological and traffic conditions. As hypothesized, the model SIRANE that can handle a street canyon configuration was the most sensitive to the built environment especially to the presence of tall buildings around the road. In contrast, CALINE exhibited the lowest sensitivity to the built environment.

  16. ROAD MAP FOR DEVELOPMENT OF CRYSTAL-TOLERANT HIGH LEVEL WASTE GLASSES

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fox, K.; Peeler, D.; Herman, C.

    The U.S. Department of Energy (DOE) is building a Tank Waste Treatment and Immobilization Plant (WTP) at the Hanford Site in Washington to remediate 55 million gallons of radioactive waste that is being temporarily stored in 177 underground tanks. Efforts are being made to increase the loading of Hanford tank wastes in glass while meeting melter lifetime expectancies and process, regulatory, and product quality requirements. This road map guides the research and development for formulation and processing of crystaltolerant glasses, identifying near- and long-term activities that need to be completed over the period from 2014 to 2019. The primary objectivemore » is to maximize waste loading for Hanford waste glasses without jeopardizing melter operation by crystal accumulation in the melter or melter discharge riser. The potential applicability to the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF) will also be addressed in this road map. The planned research described in this road map is motivated by the potential for substantial economic benefits (significant reductions in glass volumes) that will be realized if the current constraints (T1% for WTP and TL for DWPF) are approached in an appropriate and technically defensible manner for defense waste and current melter designs. The basis of this alternative approach is an empirical model predicting the crystal accumulation in the WTP glass discharge riser and melter bottom as a function of glass composition, time, and temperature. When coupled with an associated operating limit (e.g., the maximum tolerable thickness of an accumulated layer of crystals), this model could then be integrated into the process control algorithms to formulate crystal-tolerant high-level waste (HLW) glasses targeting high waste loadings while still meeting process related limits and melter lifetime expectancies. The modeling effort will be an iterative process, where model form and a broader range of conditions, e.g., glass composition and temperature, will evolve as additional data on crystal accumulation are gathered. Model validation steps will be included to guide the development process and ensure the value of the effort (i.e., increased waste loading and waste throughput). A summary of the stages of the road map for developing the crystal-tolerant glass approach, their estimated durations, and deliverables is provided.« less

  17. Validation of Water Erosion Prediction Project (WEPP) model for low-volume forest roads

    Treesearch

    William Elliot; R. B. Foltz; Charlie Luce

    1995-01-01

    Erosion rates of recently graded nongravel forest roads were measured under rainfall simulation on five different soils. The erosion rates observed on 24 forest road erosion plots were compared with values predicted by the Water Erosion Prediction Project (WEPP) Model, Version 93.1. Hydraulic conductivity and soil erodibility values were predicted from methods...

  18. GIS Data Based Automatic High-Fidelity 3D Road Network Modeling

    NASA Technical Reports Server (NTRS)

    Wang, Jie; Shen, Yuzhong

    2011-01-01

    3D road models are widely used in many computer applications such as racing games and driving simulations_ However, almost all high-fidelity 3D road models were generated manually by professional artists at the expense of intensive labor. There are very few existing methods for automatically generating 3D high-fidelity road networks, especially those existing in the real world. This paper presents a novel approach thai can automatically produce 3D high-fidelity road network models from real 2D road GIS data that mainly contain road. centerline in formation. The proposed method first builds parametric representations of the road centerlines through segmentation and fitting . A basic set of civil engineering rules (e.g., cross slope, superelevation, grade) for road design are then selected in order to generate realistic road surfaces in compliance with these rules. While the proposed method applies to any types of roads, this paper mainly addresses automatic generation of complex traffic interchanges and intersections which are the most sophisticated elements in the road networks

  19. Effects of Jefferson Road stormwater-detention basin on loads and concentrations of selected chemical constituents in East Branch of Allen Creek at Pittsford, Monroe County, New York

    USGS Publications Warehouse

    Sherwood, Donald A.

    2004-01-01

    Discharge and water-quality data collection at East Branch Allen Creek from 1990 through 2000 provide a basis for estimating the effect of the Jefferson Road detention basin on loads and concentrations of chemical constituents downstream from the basin. Mean monthly flow for the 5 years prior to construction of the detention basin (8.71 ft3/s) was slightly lower than after (9.08 ft3/s). The slightly higher mean monthly flow after basin construction may have been influenced by the peak flow for the period of record that occurred in July 1998 or variations in flow diverted from the canal. No statistically significant difference in average monthly mean flow before and after basin installation was indicated.Total phosphorus was the only constituent to show no months with significant differences in load after basin construction. Several constituents showed months with significantly smaller loads after basin construction than before, whereas some constituents showed certain months with smaller and some months with greater loads, after basin construction. Statistical analysis of the "mean monthly load" for all months before and all months after construction of the detention basin showed only one constituent (ammonia + organic nitrogen) with a significantly lower load after construction and none with higher loads.Median concentrations of ammonia + organic nitrogen showed a statistically significant decrease (from 0.78 mg/L to 0.60 mg/L) after basin installation, as did nitrite + nitrate (from 1.50 mg/L to 0.96 mg/L); in contrast, the median concentration of dissolved chloride increased from 95.5 mg/L before basin installation to 109 mg/L thereafter. A trend analysis of constituent concentrations before and after installation of the detention basin showed that total phosphorus had a downward trend after installation.Analysis of the data collected at East Branch Allen Creek indicates that the Jefferson Road detention basin, in some cases, provides an improvement (reduction) in loads of some constituents. These results are uncertain, however, because hydrologic conditions before basin installation differed from those in the 5 years that followed, and because inflow from the Erie-Barge canal may alter the water quality in the 1-mi reach between the basin outflow and the gaging station.

  20. 40 CFR 86.129-94 - Road load power, test weight, inertia weight class determination, and fuel temperature profile.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... specified driving schedule. The design of the laboratory facility should include consideration of any parameters that may affect fuel temperatures, such as solar loading, pavement heat, and relative wind... be at least 125 °F throughout the driving period. Pavement temperature shall be measured and recorded...

  1. 40 CFR 86.129-94 - Road load power, test weight, inertia weight class determination, and fuel temperature profile.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... specified driving schedule. The design of the laboratory facility should include consideration of any parameters that may affect fuel temperatures, such as solar loading, pavement heat, and relative wind... be at least 125 °F throughout the driving period. Pavement temperature shall be measured and recorded...

  2. 40 CFR 86.129-94 - Road load power, test weight, inertia weight class determination, and fuel temperature profile.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... specified driving schedule. The design of the laboratory facility should include consideration of any parameters that may affect fuel temperatures, such as solar loading, pavement heat, and relative wind... be at least 125 °F throughout the driving period. Pavement temperature shall be measured and recorded...

  3. 40 CFR 86.129-94 - Road load power, test weight, inertia weight class determination, and fuel temperature profile.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... specified driving schedule. The design of the laboratory facility should include consideration of any parameters that may affect fuel temperatures, such as solar loading, pavement heat, and relative wind... be at least 125 °F throughout the driving period. Pavement temperature shall be measured and recorded...

  4. 40 CFR 86.129-94 - Road load power, test weight, inertia weight class determination, and fuel temperature profile.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... specified driving schedule. The design of the laboratory facility should include consideration of any parameters that may affect fuel temperatures, such as solar loading, pavement heat, and relative wind... be at least 125 °F throughout the driving period. Pavement temperature shall be measured and recorded...

  5. 40 CFR 85.2219 - Idle test with loaded preconditioning-EPA 91.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... concentration of CO plus CO2 falls below 6 percent or the vehicle's engine stalls at any time during the test... the overall maximum test time. (b) Test sequence. (1) The test sequence consists of a first-chance... indicator or road-load controller. (ii) The vehicle is tested in as-received condition with all accessories...

  6. 40 CFR 85.2219 - Idle test with loaded preconditioning-EPA 91.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... concentration of CO plus CO2 falls below 6 percent or the vehicle's engine stalls at any time during the test... the overall maximum test time. (b) Test sequence. (1) The test sequence consists of a first-chance... indicator or road-load controller. (ii) The vehicle is tested in as-received condition with all accessories...

  7. 14. OBLIQUE VIEW OF UPPER ORE BIN AND LOADING DECK, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. OBLIQUE VIEW OF UPPER ORE BIN AND LOADING DECK, LOOKING WEST. DETAIL OF SUPPORTING TIMBERS. THE LOCATION OF THIS ORE BIN IN RELATION TO THE MILL CAN BE SEEN IN MANY OF THE MILL OVERVIEWS. (CA-290-4 THROUGH CA-290-8). - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

  8. 44. HISTORIC VIEW LOOKING WEST AT THE TEST STAND AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    44. HISTORIC VIEW LOOKING WEST AT THE TEST STAND AND ROCKET BEING PREPARED FOR TESTING. NOTE THE LOAD CELL APPARATUS ABOVE THE ROCKET AND THE EQUIPMENT PLATFORM TO THE LEFT OF THE LOAD CELL HAVE BEEN ENCLOSED FOR PROTECTION FROM THE CLIMATE. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

  9. Emissions of organic pollutants from traffic and roads: Priority pollutants selection and substance flow analysis.

    PubMed

    Markiewicz, Anna; Björklund, Karin; Eriksson, Eva; Kalmykova, Yuliya; Strömvall, Ann-Margret; Siopi, Anna

    2017-02-15

    A large number of organic pollutants (OPs) emitted from vehicles and traffic-related activities exhibit environmental persistence and a tendency to bioaccumulate, and may have detrimental long-term effects on aquatic life. The aim of the study was to establish a list of significant sources of OPs occurring in road runoff, identify the OPs emitted from these sources, select a number of priority pollutants (PP), and estimate the quantity of PPs emitted in a road environment case study using substance flow analysis (SFA). The priority pollutants included in the SFA were selected from a list of approximately 1100 compounds found after comprehensive screening, including literature and database searches, expert judgments, the Ranking and Identification of Chemical Hazards method, and chemical analysis of sediments. The results showed the following priority order: polycyclic aromatic hydrocarbons (PAHs)>alkanes C 20 -C 40 >alkylphenols>phthalates>aldehydes>phenolic antioxidants>bisphenol A>oxygenated-PAHs>naphtha C 5 -C 12 >amides>amines. Among these, PAHs were chosen for a SFA, which was performed for a highway case study area in Gothenburg (Sweden). The SFA showed that the main sources of PAHs emitted in the area were vehicle exhaust gases, followed by tyre wear, motor lubricant oils, road surface wear, and brake linings. Only 2-6% of the total 5.8-29kg annually emitted PAHs/ha ended up in the stormwater sewer system. The measured PAH loads were found in much smaller amounts than the calculated loads and the outflow to stormwater contained much more of the hazardous PAHs than the total loads emitted in the catchment area. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  10. An effective approach for road asset management through the FDTD simulation of the GPR signal

    NASA Astrophysics Data System (ADS)

    Benedetto, Andrea; Pajewski, Lara; Adabi, Saba; Kusayanagi, Wolfgang; Tosti, Fabio

    2015-04-01

    Ground-penetrating radar is a non-destructive tool widely used in many fields of application including pavement engineering surveys. Over the last decade, the need for further breakthroughs capable to assist end-users and practitioners as decision-support systems in more effective road asset management is increasing. In more details and despite the high potential and the consolidated results obtained over years by this non-destructive tool, pavement distress manuals are still based on visual inspections, so that only the effects and not the causes of faults are generally taken into account. In this framework, the use of simulation can represent an effective solution for supporting engineers and decision-makers in understanding the deep responses of both revealed and unrevealed damages. In this study, the potential of using finite-difference time-domain simulation of the ground-penetrating radar signal is analyzed by simulating several types of flexible pavement at different center frequencies of investigation typically used for road surveys. For these purposes, the numerical simulator GprMax2D, implementing the finite-difference time-domain method, was used, proving to be a highly effective tool for detecting road faults. In more details, comparisons with simplified undisturbed modelled pavement sections were carried out showing promising agreements with theoretical expectations, and good chances for detecting the shape of damages are demonstrated. Therefore, electromagnetic modelling has proved to represent a valuable support system in diagnosing the causes of damages, even for early or unrevealed faults. Further perspectives of this research will be focused on the modelling of more complex scenarios capable to represent more accurately the real boundary conditions of road cross-sections. Acknowledgements - This work has benefited from networking activities carried out within the EU funded COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar".

  11. ViSTREET: An Educational Virtual Environment for the Teaching of Road Safety Skills to School Students

    NASA Astrophysics Data System (ADS)

    Chuah, Kee Man; Chen, Chwen Jen; Teh, Chee Siong

    Virtual reality (VR) has been prevalently used as a tool to help students learn and to simulate situations that are too hazardous to practice in real life. The present study aims to explore the capability of VR to achieve these two purposes and demonstrate a novel application of the result, using VR to help school students learn about road safety skills, which are impractical to be carried out in real-life situations. This paper describes the system design of the VR-based learning environment known as Virtual Simulated Traffics for Road Safety Education (ViSTREET) and its various features. An overview of the technical procedures for its development is also included. Ultimately, this paper highlights the potential use of VR in addressing the learning problem concerning road safety education programme in Malaysia.

  12. Comparisons of sediment losses from a newly constructed cross-country natural gas pipeline and an existing in-road pipeline

    Treesearch

    Pamela J. Edwards; Bridget M. Harrison; Daniel J. Holz; Karl W.J. Williard; Jon E. Schoonover

    2014-01-01

    Sediment loads were measured for about one year from natural gas pipelines in two studies in north central West Virginia. One study involved a 1-year-old pipeline buried within the bed of a 25-year-old skid road, and the other involved a newly constructed cross-country pipeline. Both pipelines were the same diameter and were installed using similar trenching and...

  13. The assessment of engine losses due to friction and lubricant limitations. Final report May 80-Mar 81

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Taylor, C.F.; Taylor, T. Jr; Kallin, R.L.

    A major area for improving the efficiency of spark ignition and diesel engines is a reduction of frictional losses. Existing literature on engine friction was used as a basis for estimating possible gains in engine fuel economy which look promising within the constraints of modern practice. The means considered include reduction in oil viscosity, increase in bearing and piston clearances, possible changes in piston and valve gear design, and reduction of pumping losses. Estimates indicate potential fuel consumption improvements of 3 to 4% for Otto-Cycle at wide open throttle, 7 to 9% for Otto-Cycle at road load, 4 to 5%more » for diesel at wide open throttle, and 6% for diesel at road-load. Much larger gains at road load could be obtained by using a stratified charge system which requires no air throttling. A literature search on techniques for measuring engine friction under firing conditions was also performed and various concepts employing Pressure-Volume Indicator Diagrams were assessed. Balanced pressure and direct pressure measurement in concert with instantaneous measurement of piston position provide the most reliable and repeatable assessment of engine efficiency. Pressure measurements in the range of 1/2 to 1% are achievable with digital processing techniques reducing dramatically the time and effort to generate P-V Indicator Diagrams.« less

  14. Design of micro bending deformer for optical fiber weight sensor

    NASA Astrophysics Data System (ADS)

    Ula, R. K.; Hanto, D.; Waluyo, T. B.; Adinanta, H.; Widiyatmoko, B.

    2017-04-01

    The road damage due to excessive load is one of the causes of accidents on the road. A device to measure weight of the passing vehicles needs to be planted in the road structure. Thus, a weight sensor for the passing vehicles is required. In this study, we designed a weight sensor for a static load based on a power loss due to a micro bending on the optical fiber flanked on a board. The following main components are used i.e. LED 1310 nm as a light source, a multimode fiber optic as a transmission media and a power meter for measuring power loss. This works focuses on obtaining a suitable deformer design for weight sensor. Experimental results show that deformer design with 1.5 mm single side has level of accuracy as 4.32% while the design with 1.5 mm double side has level of accuracy as 98.77%. Increasing deformer length to 2.5 mm gives 71.18% level of accuracy for single side, and 76.94% level of accuracy for double side. Micro bending design with 1.5 mm double side has a high sensitivity and it is also capable of measuring load up to 100 kg. The sensor designed has been tested for measuring the weight of motor cycle, and it can be upgraded for measuring heavy vehicles.

  15. Responses of Roadside Soil Cation Pools to Vehicular Emission Deposition in Southern California

    NASA Astrophysics Data System (ADS)

    Rossi, R.; Bain, D. J.; Jenerette, D.; Clarke, L. W.; Wilson, K.

    2013-12-01

    Roadside soils are heavily loaded with NO3- due to vehicular emissions. This deposition likely acidifies these soils, potentially mobilizing cationic species from soil exchange sites. Acidification driven mobilization is well documented in forest soils, but poorly understood in roadside soils. Metal concentrations in park and garden soils collected from Southern California were examined across gradients of soil chemistry, road network density, climate, and geology to examine cation mobilization effects. In our samples, soil pH is not clearly related to distance from the roadside or underlying geology. However, the depletion of several elements (Al, K) is clearly observed in near-road environments. These depletion trends occur despite contrary trends, including increased soil surface areas and soil organic matter in near-road environments. Additionally, inputs from the weathering of road building materials appear to affect soil chemistry. For example, soil Ca patterns remain relatively consistent relative to roads, suggesting Ca bearing weathering products replenish soil Ca pools in near-road areas. Simple mixing models constructed using elemental ratios are consistent with road material Ca source contributions. Observed near-road patterns in soil chemistry likely influence local ecological function, shifting plant communities and soil functions. Clear understanding of these shifts is essential to the effective use of green infrastructure and other strategies utilized to control road-sourced nutrients. This analytical framework can be applied globally as road networks continue to expand and affect larger ecosystems.

  16. Fatigue cracking in road pavement

    NASA Astrophysics Data System (ADS)

    Mackiewicz, P.

    2018-05-01

    The article presents the problem of modelling fatigue phenomena occurring in the road pavement. The example of two selected pavements shows the changes occurring under the influence of the load in different places of the pavement layers. Attention is paid to various values of longitudinal and transverse strains generated at the moment of passing the wheel on the pavement. It was found that the key element in the crack propagation analysis is the method of transferring the load to the pavement by the tire and the strain distribution in the pavement. During the passage of the wheel in the lower layers of the pavement, a complex stress state arises. Then vertical, horizontal and tangent stresses with various values appear. The numerical analyses carried out with the use of finite element methods allowed to assess the strain and stress changes occurring in the process of cracking road pavement. It has been shown that low-thickness pavements are susceptible to fatigue cracks arising "bottom to top", while pavements thicker are susceptible to "top to bottom" cracks. The analysis of the type of stress allowed to determine the cracking mechanism.

  17. Roads in landscape modeling: a case study of a road data layer and use in the interior northwest landscape analysis system.

    Treesearch

    Marti Aitken; Jane L. Hayes

    2006-01-01

    Roads are important ecological features of forest landscapes, but their cause-and effect relationships with other ecosystem components are only recently becoming included in integrated landscape analyses. Simulation models can help us to understand how forested landscapes respond over time to disturbance and socioeconomic factors, and potentially to address the...

  18. Computational modelling of traumatic brain injury predicts the location of chronic traumatic encephalopathy pathology

    PubMed Central

    Ghajari, Mazdak; Hellyer, Peter J; Sharp, David J

    2017-01-01

    Abstract Traumatic brain injury can lead to the neurodegenerative disease chronic traumatic encephalopathy. This condition has a clear neuropathological definition but the relationship between the initial head impact and the pattern of progressive brain pathology is poorly understood. We test the hypothesis that mechanical strain and strain rate are greatest in sulci, where neuropathology is prominently seen in chronic traumatic encephalopathy, and whether human neuroimaging observations converge with computational predictions. Three distinct types of injury were simulated. Chronic traumatic encephalopathy can occur after sporting injuries, so we studied a helmet-to-helmet impact in an American football game. In addition, we investigated an occipital head impact due to a fall from ground level and a helmeted head impact in a road traffic accident involving a motorcycle and a car. A high fidelity 3D computational model of brain injury biomechanics was developed and the contours of strain and strain rate at the grey matter–white matter boundary were mapped. Diffusion tensor imaging abnormalities in a cohort of 97 traumatic brain injury patients were also mapped at the grey matter–white matter boundary. Fifty-one healthy subjects served as controls. The computational models predicted large strain most prominent at the depths of sulci. The volume fraction of sulcal regions exceeding brain injury thresholds were significantly larger than that of gyral regions. Strain and strain rates were highest for the road traffic accident and sporting injury. Strain was greater in the sulci for all injury types, but strain rate was greater only in the road traffic and sporting injuries. Diffusion tensor imaging showed converging imaging abnormalities within sulcal regions with a significant decrease in fractional anisotropy in the patient group compared to controls within the sulci. Our results show that brain tissue deformation induced by head impact loading is greatest in sulcal locations, where pathology in cases of chronic traumatic encephalopathy is observed. In addition, the nature of initial head loading can have a significant influence on the magnitude and pattern of injury. Clarifying this relationship is key to understanding the long-term effects of head impacts and improving protective strategies, such as helmet design. PMID:28043957

  19. A Multi-Stage Method for Connecting Participatory Sensing and Noise Simulations

    PubMed Central

    Hu, Mingyuan; Che, Weitao; Zhang, Qiuju; Luo, Qingli; Lin, Hui

    2015-01-01

    Most simulation-based noise maps are important for official noise assessment but lack local noise characteristics. The main reasons for this lack of information are that official noise simulations only provide information about expected noise levels, which is limited by the use of large-scale monitoring of noise sources, and are updated infrequently. With the emergence of smart cities and ubiquitous sensing, the possible improvements enabled by sensing technologies provide the possibility to resolve this problem. This study proposed an integrated methodology to propel participatory sensing from its current random and distributed sampling origins to professional noise simulation. The aims of this study were to effectively organize the participatory noise data, to dynamically refine the granularity of the noise features on road segments (e.g., different portions of a road segment), and then to provide a reasonable spatio-temporal data foundation to support noise simulations, which can be of help to researchers in understanding how participatory sensing can play a role in smart cities. This study first discusses the potential limitations of the current participatory sensing and simulation-based official noise maps. Next, we explain how participatory noise data can contribute to a simulation-based noise map by providing (1) spatial matching of the participatory noise data to the virtual partitions at a more microscopic level of road networks; (2) multi-temporal scale noise estimations at the spatial level of virtual partitions; and (3) dynamic aggregation of virtual partitions by comparing the noise values at the relevant temporal scale to form a dynamic segmentation of each road segment to support multiple spatio-temporal noise simulations. In this case study, we demonstrate how this method could play a significant role in a simulation-based noise map. Together, these results demonstrate the potential benefits of participatory noise data as dynamic input sources for noise simulations on multiple spatio-temporal scales. PMID:25621604

  20. A multi-stage method for connecting participatory sensing and noise simulations.

    PubMed

    Hu, Mingyuan; Che, Weitao; Zhang, Qiuju; Luo, Qingli; Lin, Hui

    2015-01-22

    Most simulation-based noise maps are important for official noise assessment but lack local noise characteristics. The main reasons for this lack of information are that official noise simulations only provide information about expected noise levels, which is limited by the use of large-scale monitoring of noise sources, and are updated infrequently. With the emergence of smart cities and ubiquitous sensing, the possible improvements enabled by sensing technologies provide the possibility to resolve this problem. This study proposed an integrated methodology to propel participatory sensing from its current random and distributed sampling origins to professional noise simulation. The aims of this study were to effectively organize the participatory noise data, to dynamically refine the granularity of the noise features on road segments (e.g., different portions of a road segment), and then to provide a reasonable spatio-temporal data foundation to support noise simulations, which can be of help to researchers in understanding how participatory sensing can play a role in smart cities. This study first discusses the potential limitations of the current participatory sensing and simulation-based official noise maps. Next, we explain how participatory noise data can contribute to a simulation-based noise map by providing (1) spatial matching of the participatory noise data to the virtual partitions at a more microscopic level of road networks; (2) multi-temporal scale noise estimations at the spatial level of virtual partitions; and (3) dynamic aggregation of virtual partitions by comparing the noise values at the relevant temporal scale to form a dynamic segmentation of each road segment to support multiple spatio-temporal noise simulations. In this case study, we demonstrate how this method could play a significant role in a simulation-based noise map. Together, these results demonstrate the potential benefits of participatory noise data as dynamic input sources for noise simulations on multiple spatio-temporal scales.

  1. Flash-Flood hydrological simulations at regional scale. Scale signature on road flooding vulnerability

    NASA Astrophysics Data System (ADS)

    Anquetin, Sandrine; Vannier, Olivier; Ollagnier, Mélody; Braud, Isabelle

    2015-04-01

    This work contributes to the evaluation of the dynamics of the human exposure during flash-flood events in the Mediterranean region. Understanding why and how the commuters modify their daily mobility in the Cévennes - Vivarais area (France) is the long-term objective of the study. To reach this objective, the methodology relies on three steps: i) evaluation of daily travel patterns, ii) reconstitution of road flooding events in the region based on hydrological simulation at regional scale in order to capture the time evolution and the intensity of flood and iii) identification of the daily fluctuation of the exposition according to road flooding scenarios and the time evolution of mobility patterns. This work deals with the second step. To do that, the physically based and non-calibrated hydrological model CVN (Vannier, 2013) is implemented to retrieve the hydrological signature of past flash-flood events in Southern France. Four past events are analyzed (September 2002; September 2005 (split in 2 different events); October 2008). Since the regional scale is investigated, the scales of the studied catchments range from few km2 to few hundreds of km2 where many catchments are ungauged. The evaluation is based on a multi-scale approach using complementary observations coming from post-flood experiments (for small and/or ungaugged catchments) and operational hydrological network (for larger catchments). The scales of risk (time and location of the road flooding) are also compared to observed data of road cuts. The discussion aims at improving our understanding on the hydrological processes associated with road flooding vulnerability. We specifically analyze runoff coefficient and the ratio between surface and groundwater flows at regional scale. The results show that on the overall, the three regional simulations provide good scores for the probability of detection and false alarms concerning road flooding (1600 points are analyzed for the whole region). Our evaluation procedure provides new insights on the active hydrological processes at small scales (catchments area < 10 km²) since these small scales, distributed over the whole region, are analyzed through road cuts data and post-flood field investigations. As shown in Vannier (2013), the signature of the altered geological layer is significant on the simulated discharges. For catchments under schisty geology, the simulated discharge, whatever the catchment size, is usually overestimated. Vannier, O, 2013, Apport de la modélisation hydrologique régionale à la compréhension des processus de crue en zone méditerranéenne, PhD-Thesis (in French), Grenoble University.

  2. libRoadRunner: a high performance SBML simulation and analysis library

    PubMed Central

    Somogyi, Endre T.; Bouteiller, Jean-Marie; Glazier, James A.; König, Matthias; Medley, J. Kyle; Swat, Maciej H.; Sauro, Herbert M.

    2015-01-01

    Motivation: This article presents libRoadRunner, an extensible, high-performance, cross-platform, open-source software library for the simulation and analysis of models expressed using Systems Biology Markup Language (SBML). SBML is the most widely used standard for representing dynamic networks, especially biochemical networks. libRoadRunner is fast enough to support large-scale problems such as tissue models, studies that require large numbers of repeated runs and interactive simulations. Results: libRoadRunner is a self-contained library, able to run both as a component inside other tools via its C++ and C bindings, and interactively through its Python interface. Its Python Application Programming Interface (API) is similar to the APIs of MATLAB (www.mathworks.com) and SciPy (http://www.scipy.org/), making it fast and easy to learn. libRoadRunner uses a custom Just-In-Time (JIT) compiler built on the widely used LLVM JIT compiler framework. It compiles SBML-specified models directly into native machine code for a variety of processors, making it appropriate for solving extremely large models or repeated runs. libRoadRunner is flexible, supporting the bulk of the SBML specification (except for delay and non-linear algebraic equations) including several SBML extensions (composition and distributions). It offers multiple deterministic and stochastic integrators, as well as tools for steady-state analysis, stability analysis and structural analysis of the stoichiometric matrix. Availability and implementation: libRoadRunner binary distributions are available for Mac OS X, Linux and Windows. The library is licensed under Apache License Version 2.0. libRoadRunner is also available for ARM-based computers such as the Raspberry Pi. http://www.libroadrunner.org provides online documentation, full build instructions, binaries and a git source repository. Contacts: hsauro@u.washington.edu or somogyie@indiana.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:26085503

  3. libRoadRunner: a high performance SBML simulation and analysis library.

    PubMed

    Somogyi, Endre T; Bouteiller, Jean-Marie; Glazier, James A; König, Matthias; Medley, J Kyle; Swat, Maciej H; Sauro, Herbert M

    2015-10-15

    This article presents libRoadRunner, an extensible, high-performance, cross-platform, open-source software library for the simulation and analysis of models expressed using Systems Biology Markup Language (SBML). SBML is the most widely used standard for representing dynamic networks, especially biochemical networks. libRoadRunner is fast enough to support large-scale problems such as tissue models, studies that require large numbers of repeated runs and interactive simulations. libRoadRunner is a self-contained library, able to run both as a component inside other tools via its C++ and C bindings, and interactively through its Python interface. Its Python Application Programming Interface (API) is similar to the APIs of MATLAB ( WWWMATHWORKSCOM: ) and SciPy ( HTTP//WWWSCIPYORG/: ), making it fast and easy to learn. libRoadRunner uses a custom Just-In-Time (JIT) compiler built on the widely used LLVM JIT compiler framework. It compiles SBML-specified models directly into native machine code for a variety of processors, making it appropriate for solving extremely large models or repeated runs. libRoadRunner is flexible, supporting the bulk of the SBML specification (except for delay and non-linear algebraic equations) including several SBML extensions (composition and distributions). It offers multiple deterministic and stochastic integrators, as well as tools for steady-state analysis, stability analysis and structural analysis of the stoichiometric matrix. libRoadRunner binary distributions are available for Mac OS X, Linux and Windows. The library is licensed under Apache License Version 2.0. libRoadRunner is also available for ARM-based computers such as the Raspberry Pi. http://www.libroadrunner.org provides online documentation, full build instructions, binaries and a git source repository. hsauro@u.washington.edu or somogyie@indiana.edu Supplementary data are available at Bioinformatics online. Published by Oxford University Press 2015. This work is written by US Government employees and is in the public domain in the US.

  4. Probabilistic load simulation: Code development status

    NASA Astrophysics Data System (ADS)

    Newell, J. F.; Ho, H.

    1991-05-01

    The objective of the Composite Load Spectra (CLS) project is to develop generic load models to simulate the composite load spectra that are included in space propulsion system components. The probabilistic loads thus generated are part of the probabilistic design analysis (PDA) of a space propulsion system that also includes probabilistic structural analyses, reliability, and risk evaluations. Probabilistic load simulation for space propulsion systems demands sophisticated probabilistic methodology and requires large amounts of load information and engineering data. The CLS approach is to implement a knowledge based system coupled with a probabilistic load simulation module. The knowledge base manages and furnishes load information and expertise and sets up the simulation runs. The load simulation module performs the numerical computation to generate the probabilistic loads with load information supplied from the CLS knowledge base.

  5. Residential Air Pollution, Road Traffic, Greenness and Maternal Hypertension: Results from GINIplus and LISAplus.

    PubMed

    Jendrossek, Mario; Standl, Marie; Koletzko, Sibylle; Lehmann, Irina; Bauer, Carl-Peter; Schikowski, Tamara; von Berg, Andrea; Berdel, Dietrich; Heinrich, Joachim; Markevych, Iana

    2017-07-01

    The public health burden of hypertension is high, but its relationship with long-term residential air pollution, road traffic, and greenness remains unclear. To investigate associations between residential air pollution, traffic, greenness, and hypertension among mothers. Information on doctor-diagnosed maternal hypertension was collected at the 15-year follow-up of two large population-based multicenter German birth cohorts-GINIplus and LISAplus (n=3063). Residential air pollution was modelled by land use regression models within the ESCAPE and universal kriging within the APMoSPHERE projects. Road traffic was defined as traffic load on major roads within a 100-m buffer around residences. Vegetation level ( ie , greenness) was defined as the mean Normalized Difference Vegetation Index in a 500-m buffer around residences and was assessed from Landsat 5 TM satellite images. All the exposure variables were averaged over three residential addresses during the last 10 years and categorized into tertiles or dichotomized. The individual associations between each of the exposure variables and hypertension were assessed using logistic regression analysis. No significant and consistent associations across different levels of adjustment were observed between the exposures of interest and hypertension. The only significant estimate was found with coarse particulate matter concentrations (OR 1.66, 95% CI 1.01 to 2.74; 3 rd vs 1 st tertile) among mothers residing in the Wesel area. No significant associations were observed with traffic load or greenness. This study does not provide evidence on detrimental effects of air pollution and road traffic or beneficial effects of greenness on hypertension among German adults.

  6. Assessing effects of changing land use practices on sediment loads in Panther Creek, north coastal California

    Treesearch

    Mary Ann Madej; Greg Bundros; Randy Klein

    2012-01-01

    Revisions to the California Forest Practice Rules since 1974 were intended to increase protection of water quality in streams draining timber harvest areas. The effects of improved timber harvesting methods and road designs on sediment loading are assessed for the Panther Creek basin, a 15.4 km2 watershed in Humboldt County, north coastal...

  7. Groundwater and surface-water interaction and effects of pumping in a complex glacial-sediment aquifer, phase 2, east-central Massachusetts

    USGS Publications Warehouse

    Eggleston, Jack R.; Zarriello, Phillip J.; Carlson, Carl S.

    2015-12-31

    Model simulations indicate that under average base-flow conditions, the Birch Road wells have a small effect on flow in the Sudbury River during most months, even at the maximum pumping rate of 4.9 ft3/s (3.17 Mgal/d). Maximum percent streamflow depletion in the Sudbury River caused by simulated pumping takes place during simulated drought conditions, when streamflow decreased by as much as 21 percent under maximum continuous pumping. Simulations also indicate that groundwater withdrawals at the Birch Road site could be managed so that adverse streamflow impacts are substantially ameliorated. Under the most ecologically conservative simulated drought conditions, simulated streamflow depletion was reduced from 21 percent to 3 percent by pumping at the maximum rate for 6 months rather than for 12 months. Simulations that return 10 percent of the Birch Road well withdrawals to Pod Meadow Pond indicate a modest reduction in the Sudbury River streamflow depletion and provide a larger percentage increase to streamflow just downstream of the pond. The groundwater model also indicates that well locations can have a large effect on the sustainable pumping rate and so should be chosen carefully. The model provides a tool for evaluating alternative pumping rates and schedules not included in this analysis.

  8. Using road markings as a continuous cue for speed choice.

    PubMed

    Charlton, Samuel G; Starkey, Nicola J; Malhotra, Neha

    2018-08-01

    The potential for using road markings to indicate speed limits was investigated in a driving simulator over the course of two sessions. Two types of experimental road markings, an "Attentional" set designed to provide visually distinct cues to indicate speed limits of 60, 80 and 100 km/h, and a "Perceptual" set designed to also affect drivers' perception of speed, were compared to a standard undifferentiated set of markings. Participants (n = 20 per group) were assigned to one of four experimental groups (Attentional-Explicit, Attentional-Implicit, Perceptual-Explicit, Perceptual-Implicit) or a Control group (n = 22; standard road markings). The Explicit groups were instructed about the meaning of the road markings while those in the Implicit and Control groups did not receive any explanation. Participants drove five 10 km simulated roads containing three speed zones (60, 80 and 100 km/h) during the first session. The participants returned to the laboratory approximately 3 days later to drive five more trials including roads they had not seen before, a trial that included a secondary task, and a trial where speed signs were removed and only markings were present. The findings indicated that both types of road markings improved drivers' compliance with speed limits compared to the control group, but that explicit instruction as to the meaning of the markings was needed to realise their full benefit. Although previous research has indicated the benefit of road markings used as warnings to indicate speed reductions in advance of horizontal or vertical curves, the findings of the present experiment also suggest that systematically associating road markings with specific speed limits may be a useful way to improve speed limit compliance and increase speed homogeneity. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  9. Boundary Connection Behavior and Connection Design for Retrofitted Unreinforced Masonry Walls Subjected to Blast Loads (Preprint)

    DTIC Science & Technology

    2010-02-01

    supports. Figure 2 – FBD of Retrofitting Component The new deformed axial length of t he m embrane resulting from the applied lateral load is...BLAST LOADS John Hoemann U.S. Army Engineer Research & Development Center (CEERD-GS-V) 3909 Halls Ferry Road Vicksburg, MS 39180 James... joint owner of the work. If published, ASCE Structures Congress may assert copyright. If so, the United States has for itself and others acting on

  10. High burn-up spent nuclear fuel transport reliability investigation

    DOE PAGES

    Wang, Jy-An; Wang, Hong; Jiang, Hao; ...

    2018-04-15

    Transportation packages for spent nuclear fuel (SNF) must meet safety requirements under normal and accident conditions as specified by federal regulations. During road or rail transportation, SNF will experience unique conditions that could affect the structural integrity of the cladding due to vibrational and impact loading. Lack of SNF inertia-induced dynamic fatigue data, especially for the high burn-up (HBU) SNF systems, has brought significant challenges to quantify the reliability of SNF during transportation with a high degree of confidence. To address this shortcoming, Oak Ridge National Laboratory (ORNL) developed a SNF vibration testing protocol without fuel pellets removal, which hasmore » provided significant insight regarding the dynamics of mechanical interactions between pellet and cladding. This research has provided a detailed understanding about the effect of loading rate and loading mode on the fatigue damage evolution of HBU SNF under normal conditions of transport (NCT). Static and dynamic loading experimental data were generated for SNF under simulated transportation environments using a cyclic integrated reversible-bending fatigue tester (CIRFT), an enabling hot-cell testing technology developed at ORNL. SNF flexural tensile strength and fatigue S-N data from pressurized water reactors (PWRs) and boiling water reactor (BWR) HBU SNF are presented in this paper, including the potential effects of pellet-cladding interface bonding, hydride reorientation, and thermal annealing to SNF vibration reliability. The data presented here can be used to meet the nuclear industry and U.S. Nuclear Regulatory Commission needs in safety of SNF transportation operations.« less

  11. High burn-up spent nuclear fuel transport reliability investigation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Jy-An; Wang, Hong; Jiang, Hao

    Transportation packages for spent nuclear fuel (SNF) must meet safety requirements under normal and accident conditions as specified by federal regulations. During road or rail transportation, SNF will experience unique conditions that could affect the structural integrity of the cladding due to vibrational and impact loading. Lack of SNF inertia-induced dynamic fatigue data, especially for the high burn-up (HBU) SNF systems, has brought significant challenges to quantify the reliability of SNF during transportation with a high degree of confidence. To address this shortcoming, Oak Ridge National Laboratory (ORNL) developed a SNF vibration testing protocol without fuel pellets removal, which hasmore » provided significant insight regarding the dynamics of mechanical interactions between pellet and cladding. This research has provided a detailed understanding about the effect of loading rate and loading mode on the fatigue damage evolution of HBU SNF under normal conditions of transport (NCT). Static and dynamic loading experimental data were generated for SNF under simulated transportation environments using a cyclic integrated reversible-bending fatigue tester (CIRFT), an enabling hot-cell testing technology developed at ORNL. SNF flexural tensile strength and fatigue S-N data from pressurized water reactors (PWRs) and boiling water reactor (BWR) HBU SNF are presented in this paper, including the potential effects of pellet-cladding interface bonding, hydride reorientation, and thermal annealing to SNF vibration reliability. The data presented here can be used to meet the nuclear industry and U.S. Nuclear Regulatory Commission needs in safety of SNF transportation operations.« less

  12. A statistical analysis of the impact of advertising signs on road safety.

    PubMed

    Yannis, George; Papadimitriou, Eleonora; Papantoniou, Panagiotis; Voulgari, Chrisoula

    2013-01-01

    This research aims to investigate the impact of advertising signs on road safety. An exhaustive review of international literature was carried out on the effect of advertising signs on driver behaviour and safety. Moreover, a before-and-after statistical analysis with control groups was applied on several road sites with different characteristics in the Athens metropolitan area, in Greece, in order to investigate the correlation between the placement or removal of advertising signs and the related occurrence of road accidents. Road accident data for the 'before' and 'after' periods on the test sites and the control sites were extracted from the database of the Hellenic Statistical Authority, and the selected 'before' and 'after' periods vary from 2.5 to 6 years. The statistical analysis shows no statistical correlation between road accidents and advertising signs in none of the nine sites examined, as the confidence intervals of the estimated safety effects are non-significant at 95% confidence level. This can be explained by the fact that, in the examined road sites, drivers are overloaded with information (traffic signs, directions signs, labels of shops, pedestrians and other vehicles, etc.) so that the additional information load from advertising signs may not further distract them.

  13. Vehicle operation characteristic under different ramp entrance conditions in underground road: Analysis, simulation and modelling

    NASA Astrophysics Data System (ADS)

    Yao, Qiming; Liu, Shuo; Liu, Yang

    2018-05-01

    An experimental design was used to study the vehicle operation characteristics of different ramp entrance conditions in underground road. With driving simulator, the experimental scenarios include left or right ramp with first, second and third service level, respectively, to collect vehicle speed, acceleration, lateral displacement and location information at the ramp entrance section. By using paired t-test and ANOVA, the influence factors of vehicle operating characteristics are studied. The result shows that effects of ramp layout and mainline traffic environment on vehicle operation characteristics are significant. The regression model of vehicle traveling distance on acceleration lane is established. Suggestions are made for ramp entrance design of underground road.

  14. Costs and environmental impacts of harvesting timber in Appalachia with a truck-mounted crane

    Treesearch

    J. N. Kochenderfer; G. W. Wendel

    1980-01-01

    A truck-mounted crane was used to yard and load timber from a 30-acre sale in a 140-acre watershed in the mountains of north-central West Virginia. A total logging cost, excluding road costs, of $44.35/M bm for logs delivered to a mill 20 miles away was comparable to that reported for wheeled skidders. Road costs with gravel would add $55/M bm, without gravel $26/M bm...

  15. Evaluation of Exhaust Emissions from Three Diesel-Hybrid Cars and Simulation of After-Treatment Systems for Ultralow Real-World NOx Emissions.

    PubMed

    Franco, Vicente; Zacharopoulou, Theodora; Hammer, Jan; Schmidt, Helge; Mock, Peter; Weiss, Martin; Samaras, Zissis

    2016-12-06

    Hybridization offers great potential for decreasing pollutant and carbon dioxide emissions of diesel cars. However, an assessment of the real-world emissions performance of modern diesel hybrids is missing. Here, we test three diesel-hybrid cars on the road and benchmark our findings with two cars against tests on the chassis dynamometer and model simulations. The pollutant emissions of the two cars tested on the chassis dynamometer were in compliance with the relevant Euro standards over the New European Driving Cycle and Worldwide harmonized Light vehicles Test Procedure. On the road, all three diesel-hybrids exceeded the regulatory NO x limits (average exceedance for all trips: +150% for the Volvo, +510% for the Peugeot, and +550% for the Mercedes-Benz) and also showed elevated on-road CO 2 emissions (average exceedance of certification values: +178, +77, and +52%, respectively). These findings point to a wide discrepancy between certified and on-road CO 2 and suggest that hybridization alone is insufficient to achieve low-NO x emissions of diesel powertrains. Instead, our simulation suggests that properly calibrated selective catalytic reduction filter and lean-NO x trap after-treatment technologies can reduce the on-road NO x emissions to 0.023 and 0.068 g/km on average, respectively, well below the Euro 6 limit (0.080 g/km).

  16. Dust loading of the normal atmosphere

    NASA Astrophysics Data System (ADS)

    Hall, F. F., Jr.

    1983-01-01

    Soil dust can contribute to atmospheric turbidity over most of the globe. The major sources of this dust are in the world's arid regions, where loadings of over 1000 micrograms/cu m can occur during strong winds. Saharan dust transported across the Atlantic can produce loadings up to 100 micrograms/cu m in the Western Hemisphere. Asian sources yield springtime loadings of 5-10 micrograms/cu m at Midway Island. Other important sources of dust are agricultural plowing and vehicular traffic on graded roads. The U.S. air quality standard of 75 micrograms/cu m is often exceeded in rural areas.

  17. Near-Source Modeling Updates: Building Downwash & Near-Road

    EPA Science Inventory

    The presentation describes recent research efforts in near-source model development focusing on building downwash and near-road barriers. The building downwash section summarizes a recent wind tunnel study, ongoing computational fluid dynamics simulations and efforts to improve ...

  18. Heavy metals in soils along unpaved roads in south west Cameroon: Contamination levels and health risks.

    PubMed

    Ngole-Jeme, Veronica M

    2016-04-01

    Soils enriched with heavy metals from vehicular emission present a significant exposure route of heavy metals to individuals using unpaved roads. This study assessed the extent of Cd, Cr, Co, Cu, Ni, Pb and Zn contamination of soils along unpaved roads in Cameroon, and the health risks presented by incidental ingestion and dermal contact with the soils using metal contamination factor (CF) pollution load index, hazard quotients (HQ) and chronic hazard index (CHI). CF values obtained (0.9-12.2) indicate moderate to high contamination levels. HQ values for Cr, Cd and Pb exceeded the reference doses. Moderate health hazard exists for road users in the areas with intense anthropogenic activities and high average daily traffic (ADT) volume according to CHI values (1-4) obtained. The economy and quality of life in cities with unpaved roads could be threatened by health challenges resulting from long-term exposure to heavy metal derived from high ADT volumes.

  19. Impact of Oncoming Headlight Glare With Cataracts: A Pilot Study

    PubMed Central

    Hwang, Alex D.; Tuccar-Burak, Merve; Goldstein, Robert; Peli, Eli

    2018-01-01

    Purpose: Oncoming headlight glare (HLG) reduces the visibility of objects on the road and may affect the safety of nighttime driving. With cataracts, the impact of oncoming HLG is expected to be more severe. We used our custom HLG simulator in a driving simulator to measure the impact of HLG on pedestrian detection by normal vision subjects with simulated mild cataracts and by patients with real cataracts. Methods: Five normal vision subjects drove nighttime scenarios under two HLG conditions (with and without HLG: HLGY and HLGN, respectively), and three vision conditions (with plano lens, simulated mild cataract, and optically blurred clip-on). Mild cataract was simulated by applying a 0.8 Bangerter diffusion foil to clip-on plano lenses. The visual acuity with the optically blurred lenses was individually chosen to match the visual acuity with the simulated cataract clip-ons under HLGN. Each nighttime driving scenario contains 24 pedestrian encounters, encompassing four pedestrian types; walking along the left side of the road, walking along the right side of the road, crossing the road from left to right, and crossing the road from right to left. Pedestrian detection performances of five patients with mild real cataracts were measured using the same setup. The cataract patients were tested only in HLGY and HLGN conditions. Participants’ visual acuity and contrast sensitivity were also measured in the simulator with and without stationary HLG. Results: For normal vision subjects, both the presence of oncoming HLG and wearing the simulated cataract clip-on reduced pedestrian detection performance. The subjects performed worst in events where the pedestrian crossed from the left, followed by events where the pedestrian crossed from the right. Significant interactions between HLG condition and other factors were also found: (1) the impact of oncoming HLG with the simulated cataract clip-on was larger than with the plano lens clip-on, (2) the impact of oncoming HLG was larger with the optically blurred clip-on than with the plano lens clip-on, but smaller than with the simulated cataract clip-on, and (3) the impact was larger for the pedestrians that crossed from the left than those that crossed from the right, and for the pedestrians walking along the left side of the road than walking along the right side of the road, suggesting that the pedestrian proximity to the glare source contributed to the performance reduction. Under HLGN, almost no pedestrians were missed with the plano lens or the simulated cataract clip-on (0 and 0.5%, respectively), but under HLGY, the rate of pedestrian misses increased to 0.5 and 6%, respectively. With the optically blurred clip-on, the percent of missed pedestrians under HLGN and HLGY did not change much (5% and 6%, respectively). Untimely response rate increased under HLGY with the plano lens and simulated cataract clip-ons, but the increase with the simulated cataract clip-on was significantly larger than with the plano lens clip-on. The contrast sensitivity with the simulated cataract clip-on was significantly degraded under HLGY. The visual acuity with the plano lens clip-on was significantly improved under HLGY, possibly due to pupil myosis. The impact of HLG measured for real cataract patients was similar to the impact on performance of normal vision subjects with simulated cataract clip-ons. Conclusion: Even with mild (simulated or real) cataracts, a substantial negative effect of oncoming HLG was measurable in the detection of crossing and walking-along pedestrians. The lowered pedestrian detection rates and longer response times with HLGY demonstrate a possible risk that oncoming HLG poses to patients driving with cataracts. PMID:29559933

  20. Generating strain signals under consideration of road surface profiles

    NASA Astrophysics Data System (ADS)

    Putra, T. E.; Abdullah, S.; Schramm, D.; Nuawi, M. Z.; Bruckmann, T.

    2015-08-01

    The current study aimed to develop the mechanism for generating strain signal utilising computer-based simulation. The strain data, caused by the acceleration, were undertaken from a fatigue data acquisition involving car movements. Using a mathematical model, the measured strain signals yielded to acceleration data used to describe the bumpiness of road surfaces. The acceleration signals were considered as an external disturbance on generating strain signals. Based on this comparison, both the actual and simulated strain data have similar pattern. The results are expected to provide new knowledge to generate a strain signal via a simulation.

  1. Analysis on mechanics response of long-life asphalt pavement at moist hot heavy loading area

    NASA Astrophysics Data System (ADS)

    Xu, Xinquan; Li, Hao; Wu, Chuanhai; Li, Shanqiang

    2018-04-01

    Based on the durability of semi-rigid base asphalt pavement test road in Guangdong Yunluo expressway, by comparing the mechanics response of modified semi-rigid base, RCC base and inverted semi-rigid base with the state of continuous, using four unit five parameter model to evaluate rut depth of asphalt pavement structure, and through commonly used fatigue life prediction model to evaluate fatigue performance of three types of asphalt pavement structure. Theoretical calculation and four years tracking observation results of test road show that rut depth of modified semi-rigid base asphalt pavement is the minimum, the road performance is the best, and the fatigue performance is the optimal.

  2. Exact-Differential Large-Scale Traffic Simulation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hanai, Masatoshi; Suzumura, Toyotaro; Theodoropoulos, Georgios

    2015-01-01

    Analyzing large-scale traffics by simulation needs repeating execution many times with various patterns of scenarios or parameters. Such repeating execution brings about big redundancy because the change from a prior scenario to a later scenario is very minor in most cases, for example, blocking only one of roads or changing the speed limit of several roads. In this paper, we propose a new redundancy reduction technique, called exact-differential simulation, which enables to simulate only changing scenarios in later execution while keeping exactly same results as in the case of whole simulation. The paper consists of two main efforts: (i) amore » key idea and algorithm of the exact-differential simulation, (ii) a method to build large-scale traffic simulation on the top of the exact-differential simulation. In experiments of Tokyo traffic simulation, the exact-differential simulation shows 7.26 times as much elapsed time improvement in average and 2.26 times improvement even in the worst case as the whole simulation.« less

  3. Development of High Fidelity Mobility Simulation of an Autonomous Vehicle in an Off-Road Scenario Using Integrated Sensor, Controller, and Multi-Body Dynamics

    DTIC Science & Technology

    2011-08-04

    AND MULTI-BODY DYNAMICS Jayakumar , Smith, Ross, Jategaonkar, Konarzewski 4 August 2011 UNCLASSIFIED: Distribution Statement A. Approved for public...Autonomous Vehicle in an Off-Road Scenario Using Integrated Sensor, Controller, and Multi-Body Dynamics 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM...Cannot neglect vehicle dynamics 4 August 2011 3 UNCLASSIFIED Importance of Simulation Fidelity • Performance evaluation requires entire system

  4. "Dispersion modeling approaches for near road

    EPA Science Inventory

    Roadway design and roadside barriers can have significant effects on the dispersion of traffic-generated pollutants, especially in the near-road environment. Dispersion models that can accurately simulate these effects are needed to fully assess these impacts for a variety of app...

  5. Developing an integrated system for mechanical reduction of fuel loads at the wildland/urban interface in the southern United States

    Treesearch

    John A. Stanturf; Robert Rummer; M. Wimberly; Timothy G. Rials; Philip. A. Araman; Rodney Busby; James Granskog; Leslie Groom

    2003-01-01

    Prescribed fire is used routinely in the southern United States to reduce fuel loading and decrease the risk of catastrophic wildfires, improve forest health, and manage threatened and endangered species. With rapid human population growth, southern forests have become fragmented by an extensive road network and intertwined with urban uses in a wildland-urban interface...

  6. "Twentytwo horses struggling with the 30,000 pound load on the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    "Twenty-two horses struggling with the 30,000 pound load on the mountain road. Eighteen animals are in front and four are on the push-pole behind." San Joaquin Light and Power Magazine, Vol. 1, No. 12, December 1913, p. 551 - Tule River Hydroelectric Complex, CA Highway 190 at North Fork of Middle Fork of Tule River, Springville, Tulare County, CA

  7. Study of the seismic performance of hybrid A-frame micropile/MSE (mechanically stabilized earth) wall

    NASA Astrophysics Data System (ADS)

    Chen, Yumin; Zhang, Zhichao; Liu, Hanlong

    2017-04-01

    The Hybrid A-Frame Micropile/MSE (mechanically stabilized earth) Wall suitable for mountain roadways is put forward in this study: a pair of vertical and inclined micropiles goes through the backfill region of a highway MSE Wall from the road surface and are then anchored into the foundation. The pile cap and grade beam are placed on the pile tops, and then a road barrier is connected to the grade beam by connecting pieces. The MSE wall's global stability, local stability and impact resistance of the road barrier can be enhanced simultaneously by this design. In order to validate the serviceability of the hybrid A-frame micropile/MSE wall and the reliability of the numerical method, scale model tests and a corresponding numerical simulation were conducted. Then, the seismic performance of the MSE walls before and after reinforcement with micropiles was studied comparatively through numerical methods. The results indicate that the hybrid A-frame micropile/MSE wall can effectively control earthquake-induced deformation, differential settlement at the road surface, bearing pressure on the bottom and acceleration by means of a rigid-soft combination of micropiles and MSE. The accumulated displacement under earthquakes with amplitude of 0.1‒0.5 g is reduced by 36.3%‒46.5%, and the acceleration amplification factor on the top of the wall is reduced by 13.4%, 15.7% and 19.3% based on 0.1, 0.3 and 0.5 g input earthquake loading, respectively. In addition, the earthquake-induced failure mode of the MSE wall in steep terrain is the sliding of the MSE region along the backslope, while the micropiles effectively control the sliding trend. The maximum earthquake-induced pile bending moment is in the interface between MSE and slope foundation, so it is necessary to strengthen the reinforcement of the pile body in the interface. Hence, it is proven that the hybrid A-frame micropile/MSE wall system has good seismic performance.

  8. GPR measurements and estimation for road subgrade damage caused by neighboring train vibration load

    NASA Astrophysics Data System (ADS)

    Zhao, Yonghui; Lu, Gang; Ge, Shuangcheng

    2015-04-01

    Generally, road can be simplified as a three-layer structure, including subgrade, subbase and pavement. Subgrade is the native material underneath a constructed road. It is commonly compacted before the road construction, and sometimes stabilized by the addition of asphalt, lime or other modifiers. As the mainly supporting structure, subgrade damage would lead in pavement settlement, displacement and crack. Assessment and monitoring of the subgrade condition currently involves trial pitting and subgrade sampling. However there is a practical limit on spatial density at which trail pits and cores can be taken. Ground penetrating radar (GPR) has been widely used to characterize highway pavement profiling, concrete structure inspection and railroad track ballast estimation. GPR can improve the economics of road maintenance. Long-term train vibration load might seriously influence the stability of the subgrade of neighboring road. Pavement settlement and obvious cracks have been found at a municipal road cross-under a railway with culvert box method. GPR test was conducted to estimate the subgrade and soil within 2.0 m depth for the further road maintenance. Two survey lines were designed in each lane, and total 12 GPR sections have been implemented. Considering both the penetrating range and the resolution, a antenna with a 500 MHz central frequency was chosen for on-site GPR data collection. For data acquisition, we used the default operating environment and scanning parameters for the RAMAC system: 60kHz transmission rate, 50 ns time window, 1024 samples per scan and 0.1 m step-size. Continuous operation was used; the antenna was placed on the road surface and slowly moved along the road. The strong surrounding disturbance related to railroad and attachments, might decrease the reliability of interpretation results. Some routine process methods (including the background removing, filtering) have been applied to suppress the background noise. Additionally, attribute analysis is an important tool that focused on the multi-properties of the signal. Here, cross-correlation attribute analysis has been applied for GPR profile interpretation. It compares one trace with surrounding traces to determine degrees of similar, and improves the difference between the reflected wave from detection target and its surrounding mediums, which makes it easy to detect the anomaly that couldn't be found in original GPR time profile. It's possible to identify sections of subgrade in good or worse condition, which may require specific maintenance or trail pitting investigation.

  9. Invasive Brown Treesnake movements at road edges indicate road-crossing avoidance

    USGS Publications Warehouse

    Siers, Shane R.; Savidge, Julie S; Reed, Robert N.

    2014-01-01

    Roads have significant impacts on the dispersal of wildlife. Although this poses a threat to the abundance and diversity of desirable flora and fauna, it also affords some opportunity for enhancing control of invasive species. Roads are the most common terrain features that may affect the rate of landscape-scale movements of invasive Brown Treesnakes (Boiga irregularis) throughout Guam. We radio tracked 45 free-ranging Brown Treesnakes in close proximity to two roads in Guam and recorded instances where daily relocations of snakes spanned roads. Then we reconstructed observed movement histories with randomized turning angles, which served as a useful null hypothesis for assessing the effect of roads or road edge habitat on Brown Treesnake movement patterns. Random walk simulations demonstrated that Brown Treesnakes crossed these roads at a rate far lower than would be expected if snake movement was random with respect to roads and road edge habitat. We discuss two alternative hypotheses for these results: 1) habitat gaps posed by roads physically or behaviorally restrict snake movement; or 2) road edges provide preferred foraging habitat from which snakes are reluctant to depart. Because roads often form the boundaries of jurisdictional and management units, the effects of roads on the movement of invasive Brown Treesnakes will influence the prospects for success of future landscape-level suppression efforts.

  10. Simulation of partially saturated - saturated flow in the Caspar Creek E-road groundwater system

    Treesearch

    Jason C. Fisher

    2000-01-01

    Abstract - Over the past decade, the U.S. Forest Service has monitored the subsurface hillslope flow of the E-road swale. The swale is located in the Caspar Creek watershed near Fort Bragg, California. In hydrologic year 1990 a logging road was built across the middle section of the hillslope followed by a total clearcut of the area during the following year....

  11. Capturing Planar Tire Properties Using Static Constraint Modes

    DTIC Science & Technology

    2012-03-13

    The In-plane Dynamics of Tyres on Uneven Roads . Vehicle System Dynamics, 1996: p. 714-730 10.1080/00423119608969231. [4] Loo, M., A Model...Virginia Tech Danville, VA, 24540 jbferris@vt.edu ABSTRACT The interaction between the tire and road has long been of interest for vehicle dynamic...spindle force with respect to tire- road interference is evaluated by comparing the simulation and experimental response for a quasi-static cleat test

  12. A Study on the Effects of Alternatives to Speed Humps Using a Driving Simulator

    NASA Astrophysics Data System (ADS)

    Kim, Jong-Min; Noh, Kwan-Sub

    A road alignment which has a long straight section followed by sharp curve is dangerous, because drivers have the habit to accelerate on the long straight section and then accidents occur on the short curve as the result of speeding. This study evaluated the alternatives to speed humps in order to reduce speed safely and comfortably on roads with this incorrect road alignment. There are several speed control facilities to reduce speed on roads with wrong road alignment. The speed hump is dangerous at high speeds because drivers must reduce speed rapidly and because of the physical impact. The image hump provides less effect for drivers who already know of its presence. So, to resolve these matters, we propose a new type of speed control facility. An image hump with transverse grooving will be effective in reducing speed because the transverse grooving gives vibration and noise to drivers who are already aware of the presence of the image hump, but it does not give the hard physical impact to vehicles. The study on the effect of the alternatives to speed humps was carried out using the K-ROADS (KICT-Road Analysis Driving Simulator) which has been developed to analyze and evaluate road safety at the project HuRoSAS (Human & Road Safety Analysis System) since 2003. K-ROADS has two distinct functions. One is the visual system which has a 360 degree F. O. V. to reduce dead angles on black spots such as at-grade intersections. The other is the motion system which has high frequency vibration to reproduce vibrations made in irregular road surfaces. This study found out that the image hump with transverse grooving is a safe speed control facility in order to reduce driving speed safely and comfortably on a straight section followed by a sharp curve, even if drivers are known the existence of image hump.

  13. Looking Southwest to Dry and Wet Exterior Scrubbers at Rear ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking Southwest to Dry and Wet Exterior Scrubbers at Rear of Oxide Building - Hematite Fuel Fabrication Facility, Oxide Building & Oxide Loading Dock, 3300 State Road P, Festus, Jefferson County, MO

  14. 23 CFR 810.108 - Designation of existing facilities.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... facilities, trail blazer signs, and passenger loading areas and facilities. (2) The approval criteria in 23... approved on any public road if they facilitate more efficient use of any Federal-aid highway. (c...

  15. 23 CFR 810.108 - Designation of existing facilities.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... facilities, trail blazer signs, and passenger loading areas and facilities. (2) The approval criteria in 23... approved on any public road if they facilitate more efficient use of any Federal-aid highway. (c...

  16. 23 CFR 810.108 - Designation of existing facilities.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... facilities, trail blazer signs, and passenger loading areas and facilities. (2) The approval criteria in 23... approved on any public road if they facilitate more efficient use of any Federal-aid highway. (c...

  17. 23 CFR 810.108 - Designation of existing facilities.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... facilities, trail blazer signs, and passenger loading areas and facilities. (2) The approval criteria in 23... approved on any public road if they facilitate more efficient use of any Federal-aid highway. (c...

  18. 19 CFR 114.22 - Coverage of carnets.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... photographs (with or without sound track) showing the nature or operation of products or equipment whose... or in containers, even if the containers, without being loaded on road vehicles, are carried by other...

  19. 19 CFR 114.22 - Coverage of carnets.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... photographs (with or without sound track) showing the nature or operation of products or equipment whose... or in containers, even if the containers, without being loaded on road vehicles, are carried by other...

  20. 19 CFR 114.22 - Coverage of carnets.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... photographs (with or without sound track) showing the nature or operation of products or equipment whose... or in containers, even if the containers, without being loaded on road vehicles, are carried by other...

  1. 19 CFR 114.22 - Coverage of carnets.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... photographs (with or without sound track) showing the nature or operation of products or equipment whose... or in containers, even if the containers, without being loaded on road vehicles, are carried by other...

  2. 19 CFR 114.22 - Coverage of carnets.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... photographs (with or without sound track) showing the nature or operation of products or equipment whose... or in containers, even if the containers, without being loaded on road vehicles, are carried by other...

  3. 40 CFR 86.605-88 - Maintenance of records; submittal of information.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... under this subpart, including the following information: (A) Dynamometer. (1) Inertia loading. (2) Road...) of this section, including such extraordinary events as vehicle accident. (ix) A paper copy of the...

  4. Looking West From rear (East) End of Office Building Including ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking West From rear (East) End of Office Building Including Recycle Storage Area, Loading Docks, and Decontamination Zone - Hematite Fuel Fabrication Facility, Office, 3300 State Road P, Festus, Jefferson County, MO

  5. 3. WIDE ANGLE OF NEUTRAL BUOYANCY SIMULATOR (NBS) FROM WITHIN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. WIDE ANGLE OF NEUTRAL BUOYANCY SIMULATOR (NBS) FROM WITHIN NBS HIGHBAY DOORS. DIVE BELL IN FOREGROUND. - Marshall Space Flight Center, Neutral Buoyancy Simulator Facility, Rideout Road, Huntsville, Madison County, AL

  6. Importance of tread inertia and damping on the tyre/road contact stiffness

    NASA Astrophysics Data System (ADS)

    Winroth, J.; Andersson, P. B. U.; Kropp, W.

    2014-10-01

    Predicting tyre/road interaction processes like roughness excitation, stick-slip, stick-snap, wear and traction requires detailed information about the road surface, the tyre dynamics and the local deformation of the tread at the interface. Aspects of inertia and damping when the tread is locally deformed are often neglected in many existing tyre/road interaction models. The objective of this paper is to study how the dynamic features of the tread affect contact forces and contact stiffness during local deformation. This is done by simulating the detailed contact between an elastic layer and a rough road surface using a previously developed numerical time domain contact model. Road roughness on length scales smaller than the discretisation scale is included by the addition of nonlinear contact springs between each pair of contact elements. The dynamic case, with an elastic layer impulse response extending in time, is compared with the case where the corresponding quasi-static response is used. Results highlight the difficulty of estimating a constant contact stiffness as it increases during the indentation process between the elastic layer and the rough road surface. The stiffness-indentation relation additionally depends on how rapidly the contact develops; a faster process gives a stiffer contact. Material properties like loss factor and density also alter the contact development. This work implies that dynamic properties of the local tread deformation may be of importance when simulating contact details during normal tyre/road interaction conditions. There are however indications that the significant effect of damping could approximately be included as an increased stiffness in a quasi-static tread model.

  7. Repeatability of a dynamic rollover test system.

    PubMed

    Seppi, Jeremy; Toczyski, Jacek; Crandall, Jeff R; Kerrigan, Jason

    2016-08-17

    The goal of this study was to characterize the rollover crash and to evaluate the repeatability of the Dynamic Rollover Test System (DRoTS) in terms of initial roof-to-ground contact conditions, vehicle kinematics, road reaction forces, and vehicle deformation. Four rollover crash tests were performed on 2 pairs of replicate vehicles (2 sedan tests and 2 compact multipurpose van [MPV] tests), instrumented with a custom inertial measurement unit to measure vehicle and global kinematics and string potentiometers to measure pillar deformation time histories. The road was instrumented with load cells to measure reaction loads and an optical encoder to measure road velocity. Laser scans of pre- and posttest vehicles were taken to provide detailed deformation maps. Initial conditions were found to be repeatable, with the largest difference seen in drop height of 20 mm; roll rate, roll angle, pitch angle, road velocity, drop velocity, mass, and moment of inertia were all 7% different or less. Vehicle kinematics (roll rate, road speed, roll and pitch angle, global Z' acceleration, and global Z' velocity) were similar throughout the impact; however, differences were seen in the sedan tests because of a vehicle fixation problem and differences were seen in the MPV tests due to an increase in reaction forces during leading side impact likely caused by disparities in roll angle (3° difference) and mass properties (2.2% in moment of inertia [MOI], 53.5 mm difference in center of gravity [CG] location). Despite those issues, kinetic and deformation measures showed a high degree of repeatability, which is necessary for assessing injury risk in rollover because roof strength positively correlates with injury risk (Brumbelow 2009). Improvements of the test equipment and matching mass properties will ensure highly repeatable initial conditions, vehicle kinematics, kinetics, and deformations.

  8. Understanding How Kurtosis Is Transferred from Input Acceleration to Stress Response and Its Influence on Fatigue Llife

    NASA Technical Reports Server (NTRS)

    Kihm, Frederic; Rizzi, Stephen A.; Ferguson, Neil S.; Halfpenny, Andrew

    2013-01-01

    High cycle fatigue of metals typically occurs through long term exposure to time varying loads which, although modest in amplitude, give rise to microscopic cracks that can ultimately propagate to failure. The fatigue life of a component is primarily dependent on the stress amplitude response at critical failure locations. For most vibration tests, it is common to assume a Gaussian distribution of both the input acceleration and stress response. In real life, however, it is common to experience non-Gaussian acceleration input, and this can cause the response to be non-Gaussian. Examples of non-Gaussian loads include road irregularities such as potholes in the automotive world or turbulent boundary layer pressure fluctuations for the aerospace sector or more generally wind, wave or high amplitude acoustic loads. The paper first reviews some of the methods used to generate non-Gaussian excitation signals with a given power spectral density and kurtosis. The kurtosis of the response is examined once the signal is passed through a linear time invariant system. Finally an algorithm is presented that determines the output kurtosis based upon the input kurtosis, the input power spectral density and the frequency response function of the system. The algorithm is validated using numerical simulations. Direct applications of these results include improved fatigue life estimations and a method to accelerate shaker tests by generating high kurtosis, non-Gaussian drive signals.

  9. Priority of road maintenance management based on halda reading range on NAASRA method

    NASA Astrophysics Data System (ADS)

    Surbakti, M.; Doan, A.

    2018-02-01

    The road pavement, constantly experiencing stress-strain due to traffic load through it, can cause damage to the pavement. Therefore, early detection and repair of the damage will be able to prevent more severe damage that can develop into pavement failure. A road condition survey is one of the earliest attempts to detect the initial damage of a pavement. In this case the driving comfort is the most important part for the driver in assessing road conditions that are affected by the level of road surface roughness. To determine the level of roughness of the road, one of the methods developed is the measurement using the NAASRA method. In this method the roughness of the road is an accumulation of the average unevenness of the road, with the general setting on halda of 100 m. However, with this 100-meter setting, in some places the final value of the roughness value is too large or too small so that it will result in the priority of the road maintenance. This is what underlies roughness research by comparing halda settings at 50 m and 200 m different from the general settings above.This study uses the International Roughness Index (IRI) method in determining the level of road stability concerning driving discomfort. IRI score obtained from direct survey in field by using Roughometer-NAASRA.The final result shows that there is a significant difference between the reading of halda which is set at 100 m reading with halda set with 50 and 200 meter readings. This may lead to differences in handling priorities, which may impact on the sustainability of road network maintenance management (Sustainaible Road Management)

  10. Bayesian Parameter Estimation for Heavy-Duty Vehicles

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Miller, Eric; Konan, Arnaud; Duran, Adam

    2017-03-28

    Accurate vehicle parameters are valuable for design, modeling, and reporting. Estimating vehicle parameters can be a very time-consuming process requiring tightly-controlled experimentation. This work describes a method to estimate vehicle parameters such as mass, coefficient of drag/frontal area, and rolling resistance using data logged during standard vehicle operation. The method uses Monte Carlo to generate parameter sets which is fed to a variant of the road load equation. Modeled road load is then compared to measured load to evaluate the probability of the parameter set. Acceptance of a proposed parameter set is determined using the probability ratio to the currentmore » state, so that the chain history will give a distribution of parameter sets. Compared to a single value, a distribution of possible values provides information on the quality of estimates and the range of possible parameter values. The method is demonstrated by estimating dynamometer parameters. Results confirm the method's ability to estimate reasonable parameter sets, and indicates an opportunity to increase the certainty of estimates through careful selection or generation of the test drive cycle.« less

  11. Environmental and Geotechnical Assessment of the Steel Slags as a Material for Road Structure.

    PubMed

    Sas, Wojciech; Głuchowski, Andrzej; Radziemska, Maja; Dzięcioł, Justyna; Szymański, Alojzy

    2015-07-30

    Slags are the final solid wastes from the steel industry. Their production from waste and associated materials is a proper implementation of the basic objectives and principles of the waste management. This study aims to investigate the chemical and selected significant geotechnical parameters of steel slag as the alternative materials used in road construction. These investigations are strongly desired for successful application in engineering. Young's modules E , and resilient modules M r showed that their values corresponding with requirements for subbase (principal or auxiliary) and riding surface as well. Tested mechanical properties were conducted in soaked and un-soaked (optimal moisture content) conditions. The designated high content of chromium and zinc are strongly associated with the internal crystal structure of steel slag. The results do not lead to threats when they are applied in roads' structures. Mechanical characterization was obtained by performing California bearing ratio (CBR) tests for steel slag in fixed compaction and moisture content conditions. Moreover, cyclic loading of steel slag was conducted with the application of cyclic California bearing ratio (cCBR) apparatus to characterization of this material as a controlled low-strength material. Finally, field studies that consist of static load plate VSS tests were presented.

  12. Simulation of hypothetical Asian carp egg and larvae development and transport in the Lockport, Brandon Road, Dresden Island, and Marseilles Pools of the Illinois Waterway by use of the Fluvial Egg Drift Simulator (FluEgg) model

    USGS Publications Warehouse

    Murphy, Elizabeth A.; Garcia, Tatiana; Jackson, P. Ryan; Duncker, James J.

    2016-04-05

    As part of the Great Lakes and Mississippi River Interbasin Study, the U.S. Army Corps of Engineers (USACE) is conducting an assessment of the vulnerability of the Chicago Area Waterway System and Des Plaines River to Asian carp (specifically, Hypophthalmichthys nobilis (bighead carp) and Hypophthalmichthys molitrix (silver carp)) spawning and recruitment. As part of this assessment, the USACE requested the help of the U.S. Geological Survey in predicting the fate and transport of Asian carp eggs hypothetically spawned at the electric dispersal barrier on the Chicago Sanitary and Ship Canal and downstream of the Brandon Road Lock and Dam on the Des Plaines River under dry weather flow and high water temperature conditions. The Fluvial Egg Drift Simulator (FluEgg) model predicted that approximately 80 percent of silver carp eggs spawned near the electric dispersal barrier would hatch within the Lockport and Brandon Road pools (as close as 3.6 miles downstream of the barrier) and approximately 82 percent of the silver carp eggs spawned near the Brandon Road Dam would hatch in the Des Plaines River (as close as 1.6 miles downstream from the gates of Brandon Road Lock). Extension of the FluEgg model to include the fate and transport of larvae until gas bladder inflation—the point at which the larvae begin to leave the drift—suggests that eggs spawned at the electric dispersal barrier would reach the gas bladder inflation stage primarily within the Dresden Island Pool, and those spawned at the Brandon Road Dam would reach this stage primarily within the Marseilles and Starved Rock Pools.

  13. Adaptive super-twisting observer for estimation of random road excitation profile in automotive suspension systems.

    PubMed

    Rath, J J; Veluvolu, K C; Defoort, M

    2014-01-01

    The estimation of road excitation profile is important for evaluation of vehicle stability and vehicle suspension performance for autonomous vehicle control systems. In this work, the nonlinear dynamics of the active automotive system that is excited by the unknown road excitation profile are considered for modeling. To address the issue of estimation of road profile, we develop an adaptive supertwisting observer for state and unknown road profile estimation. Under Lipschitz conditions for the nonlinear functions, the convergence of the estimation error is proven. Simulation results with Ford Fiesta MK2 demonstrate the effectiveness of the proposed observer for state and unknown input estimation for nonlinear active suspension system.

  14. Adaptive Super-Twisting Observer for Estimation of Random Road Excitation Profile in Automotive Suspension Systems

    PubMed Central

    Rath, J. J.; Veluvolu, K. C.; Defoort, M.

    2014-01-01

    The estimation of road excitation profile is important for evaluation of vehicle stability and vehicle suspension performance for autonomous vehicle control systems. In this work, the nonlinear dynamics of the active automotive system that is excited by the unknown road excitation profile are considered for modeling. To address the issue of estimation of road profile, we develop an adaptive supertwisting observer for state and unknown road profile estimation. Under Lipschitz conditions for the nonlinear functions, the convergence of the estimation error is proven. Simulation results with Ford Fiesta MK2 demonstrate the effectiveness of the proposed observer for state and unknown input estimation for nonlinear active suspension system. PMID:24683321

  15. Development of High Fidelity Mobility Simulation of an Autonomous Vehicle in an Off-Road Scenario Using Integrated Sensor, Controller, and Multi-Body Dynamics

    DTIC Science & Technology

    2011-08-01

    VEHICLE IN AN OFF-ROAD SCENARIO USING INTEGRATED SENSOR, CONTROLLER, AND MULTI-BODY DYNAMICS Paramsothy Jayakumar , PhD William Smith US Army...environment for a control system, mechanical system dynamics , and sensor simulation for an improved assessment of the vehicle system performance...improve vehicle dynamic performance; we must also evaluate and improve the sensor suite employed on the vehicle, and the controller used to operate

  16. Modeling spatial decisions with graph theory: logging roads and forest fragmentation in the Brazilian Amazon.

    PubMed

    Walker, Robert; Arima, Eugenio; Messina, Joe; Soares-Filho, Britaldo; Perz, Stephen; Vergara, Dante; Sales, Marcio; Pereira, Ritaumaria; Castro, Williams

    2013-01-01

    This article addresses the spatial decision-making of loggers and implications for forest fragmentation in the Amazon basin. It provides a behavioral explanation for fragmentation by modeling how loggers build road networks, typically abandoned upon removal of hardwoods. Logging road networks provide access to land, and the settlers who take advantage of them clear fields and pastures that accentuate their spatial signatures. In shaping agricultural activities, these networks organize emergent patterns of forest fragmentation, even though the loggers move elsewhere. The goal of the article is to explicate how loggers shape their road networks, in order to theoretically explain an important type of forest fragmentation found in the Amazon basin, particularly in Brazil. This is accomplished by adapting graph theory to represent the spatial decision-making of loggers, and by implementing computational algorithms that build graphs interpretable as logging road networks. The economic behavior of loggers is conceptualized as a profit maximization problem, and translated into spatial decision-making by establishing a formal correspondence between mathematical graphs and road networks. New computational approaches, adapted from operations research, are used to construct graphs and simulate spatial decision-making as a function of discount rates, land tenure, and topographic constraints. The algorithms employed bracket a range of behavioral settings appropriate for areas of terras de volutas, public lands that have not been set aside for environmental protection, indigenous peoples, or colonization. The simulation target sites are located in or near so-called Terra do Meio, once a major logging frontier in the lower Amazon Basin. Simulation networks are compared to empirical ones identified by remote sensing and then used to draw inferences about factors influencing the spatial behavior of loggers. Results overall suggest that Amazonia's logging road networks induce more fragmentation than necessary to access fixed quantities of wood. The paper concludes by considering implications of the approach and findings for Brazil's move to a system of concession logging.

  17. Impacts of transportation sector emissions on future U.S. air quality in a changing climate. Part I: Projected emissions, simulation design, and model evaluation.

    PubMed

    Campbell, Patrick; Zhang, Yang; Yan, Fang; Lu, Zifeng; Streets, David

    2018-07-01

    Emissions from the transportation sector are rapidly changing worldwide; however, the interplay of such emission changes in the face of climate change are not as well understood. This two-part study examines the impact of projected emissions from the U.S. transportation sector (Part I) on ambient air quality in the face of climate change (Part II). In Part I of this study, we describe the methodology and results of a novel Technology Driver Model (see graphical abstract) that includes 1) transportation emission projections (including on-road vehicles, non-road engines, aircraft, rail, and ship) derived from a dynamic technology model that accounts for various technology and policy options under an IPCC emission scenario, and 2) the configuration/evaluation of a dynamically downscaled Weather Research and Forecasting/Community Multiscale Air Quality modeling system. By 2046-2050, the annual domain-average transportation emissions of carbon monoxide (CO), nitrogen oxides (NO x ), volatile organic compounds (VOCs), ammonia (NH 3 ), and sulfur dioxide (SO 2 ) are projected to decrease over the continental U.S. The decreases in gaseous emissions are mainly due to reduced emissions from on-road vehicles and non-road engines, which exhibit spatial and seasonal variations across the U.S. Although particulate matter (PM) emissions widely decrease, some areas in the U.S. experience relatively large increases due to increases in ship emissions. The on-road vehicle emissions dominate the emission changes for CO, NO x , VOC, and NH 3 , while emissions from both the on-road and non-road modes have strong contributions to PM and SO 2 emission changes. The evaluation of the baseline 2005 WRF simulation indicates that annual biases are close to or within the acceptable criteria for meteorological performance in the literature, and there is an overall good agreement in the 2005 CMAQ simulations of chemical variables against both surface and satellite observations. Copyright © 2018 Elsevier Ltd. All rights reserved.

  18. A model-based approach to monitor complex road-vehicle interactions through first principles

    NASA Astrophysics Data System (ADS)

    Chakravarty, T.; Srinivasarengan, K.; Roy, S.; Bilal, S.; Balamuralidhar, P.

    2013-02-01

    The increasing availability of portable computing devices and their interaction with physical systems ask for designing compact models and simulations to understand and characterize such interactions. For instance, monitoring a road's grade using accelerometer stationed inside a moving ground vehicle is an emerging trend in city administration. Typically the focus has largely been to develop algorithms to articulate meaning from that. But, the experimentation cannot provide with an exhaustive analysis of all scenarios and the characteristics of them. We propose an approach of modeling these interactions of physical systems with gadgets through first principles, in a compact manner to focus on limited number of interactions. We derive an approach to model the vehicle interaction with a pothole on a road, a specific case, but allowing for selectable car parameters like natural damped frequency, tire size etc, thus generalizing it. Different road profiles are also created to represent rough road with sharp irregularities. These act as excitation to the moving vehicle and the interaction is computed to determine the vertical/ lateral vibration of the system i.e vehicle with sensors using joint time-frequency signal analysis methods. The simulation is compared with experimental data for validation. We show some directions as to how simulation of such models can reveal different characteristics of the interaction through analysis of their frequency spectrum. It is envisioned that the proposed models will get enriched further as and when large data set of real life data is captured and appropriate sensitivity analysis is done.

  19. Looking North at Reactor Number One and Air Vent on ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking North at Reactor Number One and Air Vent on Fourth Floor of Oxide Building - Hematite Fuel Fabrication Facility, Oxide Building & Oxide Loading Dock, 3300 State Road P, Festus, Jefferson County, MO

  20. View of North End of Oxide Building Interior Including Roof ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of North End of Oxide Building Interior Including Roof and Wall Juncture and Crane Trolley - Hematite Fuel Fabrication Facility, Oxide Building & Oxide Loading Dock, 3300 State Road P, Festus, Jefferson County, MO

  1. Simulated effects of pumping and drought on ground-water levels and the freshwater-saltwater interface on the north fork of Long Island, New York

    USGS Publications Warehouse

    Misut, Paul E.; Schubert, Christopher E.; Bova, Richard G.; Colabufo, Steven R.

    2004-01-01

    Ground water is the sole source of freshwater on the North Fork of Long Island. Future demands for the limited freshwater supply during a prolonged drought could cause drawdowns that induce saltwater intrusion and render the supply unusable. The freshwater system on the North Fork contains several localized, hydraulically isolated aquifers bounded by salty water. The need for information on the ability of these aquifers to meet future demands prompted a 4-year study to develop a ground-water flow model to simulate several proposed pumping scenarios under long-term average conditions and during a hypothetical drought, and to delineate the resulting ground-water levels and movement of the freshwater-saltwater interface. The model code selected was SHARP, a quasi-three-dimensional finite-difference method of simulating freshwater and saltwater flow simultaneously.Two sets of four proposed pumping scenarios were evaluated. The first represented average recharge from precipitation during 2006-20; the second represented the same period and conditions except for a 5-year period of drought conditions. The average-recharge simulations used the long-term (1959-99) rate of recharge; the drought simulations applied a 20-percent reduction in recharge rate and a 20-percent increase in the 1999 rate of agricultural pumpage during 2011–15.The simulated movement of the freshwater-saltwater interface in future withdrawal and recharge scenarios indicates that the interface may rise beneath pumped wells at Inlet Drive, Brecknock Hall, Main Bayview Road, Islands End, North Road, and Alvah's Lane. Either (1) movement of the interface to within 50 feet of the well screen, (2) a large percent change in the distance between the interface and the well screen, or (3) movement of the interface through a clay layer is a cause for concern. Wellfields in which saltwater intrusion does not appear to be a cause for concern were those at Ackerly Pond, Kenney's Road, Middle Road, Rocky Point Road, and hypothetical sites where future wellfields have been proposed.

  2. Population and Activity of On-road Vehicles in MOVES2014

    EPA Science Inventory

    This report describes the sources and derivation for on-road vehicle population and activity information and associated adjustments as stored in the MOVES2014 default databases. Motor Vehicle Emission Simulator, the MOVES2014 model, is a set of modeling tools for estimating emiss...

  3. Application of a Three-Layer Photochemical Box Model in an Athens Street Canyon.

    PubMed

    Proyou, Athena G; Ziomas, Loannis C; Stathopoulos, Antony

    1998-05-01

    The aim of this paper is to show that a photochemical box model could describe the air pollution diurnal profiles within a typical street canyon in the city of Athens. As sophisticated three-dimensional dispersion models are computationally expensive and they cannot serve to simulate pollution levels in the scale of an urban street canyon, a suitably modified three-layer photochemical box model was applied. A street canyon of Athens with heavy traffic was chosen to apply the aforementioned model. The model was used to calculate pollutant concentrations during two days with meteorological conditions favoring pollutant accumulation. Road traffic emissions were calculated based on existing traffic load measurements. Meteorological data, as well as various pollutant concentrations, in order to compare with the model results, were provided by available measurements. The calculated concentrations were found to be in good agreement with measured concentration levels and show that, when traffic load and traffic composition data are available, this model can be used to predict pollution episodes. It is noteworthy that high concentrations persisted, even after additional traffic restriction measures were taken on the second day because of the high pollution levels.

  4. Traffic Incident Management in the Presence of Hazards

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Zlatanova, S.; Steenbruggen, J.

    2016-09-01

    Traffic incidents can result in different kinds of hazards (e.g., plumes) that influence the status of road networks, therefore there is a great need for incident management in the presence of the hazards. When incidents occur, the created hazards not only affect the normal road users (make them detour or blocked), but also influence the movement of first responders. Traffic managers, who are responsible for maintaining the road safety and traffic stability, should carry out quick and effective measures to manage the incidents. In this paper, we present four issues to help people better understand the situations that could occur in the management of incidents with hazards: 1). Evacuation in the presence of hazards; 2). 3D incident management; 3). Navigation support for first responders; 4). Navigation support for road users. To address these issues, we propose a solution which combines agent technology, geo-database, hazard simulation, and traffic simulation. Further research would be needed to investigate the potentials of the proposed solution in real applications.

  5. Spinning Reserve from Responsive Load

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kueck, John D; Kirby, Brendan J; Laughner, T

    2009-01-01

    As power system costs rise and capacity is strained demand response can provide a significant system reliability benefit at a potentially attractive cost. The 162 room Music Road Hotel in Pigeon Forge Tennessee agreed to host a spinning reserve test. The Tennessee Valley Authority (TVA) supplied real-time metering and monitoring expertise to record total hotel load during both normal operations and testing. Preliminary testing showed that hotel load can be curtailed by 22% to 37% depending on the outdoor temperature and the time of day. The load drop was very rapid, essentially as fast as the 2 second metering couldmore » detect.« less

  6. Foot Marching, Load Carriage, and Injury Risk

    DTIC Science & Technology

    2016-05-01

    injuries to women , 26% to men); road marching (23% for women , 24% for men); and obstacle courses (4% for women , 5% for men). This same data show an...C). Other marching injuries, such as back injuries, may occur to women of smaller frame due to the design of equipment.7 Doctrine also suggests...regarding injuries associated with Army foot marching and load-carriage activities. REFERENCES. See Appendix A for complete reference information

  7. Quantifying Grain-Size Variability of Metal Pollutants in Road-Deposited Sediments Using the Coefficient of Variation

    PubMed Central

    Wang, Xiaoxue; Li, Xuyong

    2017-01-01

    Particle grain size is an important indicator for the variability in physical characteristics and pollutants composition of road-deposited sediments (RDS). Quantitative assessment of the grain-size variability in RDS amount, metal concentration, metal load and GSFLoad is essential to elimination of the uncertainty it causes in estimation of RDS emission load and formulation of control strategies. In this study, grain-size variability was explored and quantified using the coefficient of variation (Cv) of the particle size compositions, metal concentrations, metal loads, and GSFLoad values in RDS. Several trends in grain-size variability of RDS were identified: (i) the medium class (105–450 µm) variability in terms of particle size composition, metal loads, and GSFLoad values in RDS was smaller than the fine (<105 µm) and coarse (450–2000 µm) class; (ii) The grain-size variability in terms of metal concentrations increased as the particle size increased, while the metal concentrations decreased; (iii) When compared to the Lorenz coefficient (Lc), the Cv was similarly effective at describing the grain-size variability, whereas it is simpler to calculate because it did not require the data to be pre-processed. The results of this study will facilitate identification of the uncertainty in modelling RDS caused by grain-size class variability. PMID:28788078

  8. Improving understanding of the underlying physical process of sediment wash-off from urban road surfaces

    NASA Astrophysics Data System (ADS)

    Muthusamy, Manoranjan; Tait, Simon; Schellart, Alma; Beg, Md Nazmul Azim; Carvalho, Rita F.; de Lima, João L. M. P.

    2018-02-01

    Among the urban aquatic pollutants, the most common is sediment which also acts as a transport medium for many contaminants. Hence there is an increasing interest in being able to better predict the sediment wash-off from urban surfaces. The exponential wash-off model is the most widely used method to predict the sediment wash-off. Although a number of studies proposed various modifications to the original exponential wash-off equation, these studies mostly looked into one parameter in isolation thereby ignoring the interactions between the parameters corresponding to rainfall, catchment and sediment characteristics. Hence in this study we aim (a) to investigate the effect of rainfall intensity, surface slope and initial load on wash-off load in an integrated and systematic way and (b) to subsequently improve the exponential wash-off equation focusing on the effect of the aforementioned three parameters. A series of laboratory experiments were carried out in a full-scale setup, comprising of a rainfall simulator, a 1 m2 bituminous road surface, and a continuous wash-off measuring system. Five rainfall intensities ranging from 33 to 155 mm/h, four slopes ranging from 2 to 16% and three initial loads ranging from 50 to 200 g/m2 were selected based on values obtained from the literature. Fine sediment with a size range of 300-600 μm was used for all of the tests. Each test was carried out for one hour with at least 9 wash-off samples per test collected. Mass balance checks were carried out for all the tests as a quality control measure to make sure that there is no significant loss of sand during the tests. Results show that the washed off sediment load at any given time is proportional to initial load for a given combination of rainfall intensity and surface slope. This indicates the importance of dedicated modelling of build-up so as to subsequently predict wash-off load. It was also observed that the maximum fraction that is washed off from the surface increases with both rainfall intensity and the surface slope. This observation leads to the second part of the study where the existing wash-off model is modified by introducing a capacity factor which defines this maximum fraction. This capacity factor is derived as a function of wash-off coefficient, making use of the correlation between the maximum fraction and the wash-off rate. Values of the modified wash-off coefficient are presented for all combinations of rainfall intensities and surface slopes, which can be transferred to other urban catchments with similar conditions.

  9. Rainwater utilization and storm pollution control based on urban runoff characterization.

    PubMed

    Zhang, Mulan; Chen, Hao; Wang, Jizhen; Pan, Gang

    2010-01-01

    The characteristics of urban runoffs and their impact on rainwater utilization and storm pollution control were investigated in three different functional areas of Zhengzhou City, China. The results showed that in the same rain event the pollutant loads (chemical oxygen demand (COD) and total suspended solids (TSS)) in the sampling areas were in the order of industrial area > commercial area > residential area, and within the same area the COD and TSS concentrations of road runoffs were higher than those of roof runoffs. The first flush effects in roof and road runoffs were observed, hence the initial rainwater should be treated separately to reduce rainwater utilization cost and control storm pollution. The initial roof rainfall of 2 mm in residential area, 5 mm in commercial area and 10 mm in industrial area, and the initial road rainfall of 4 mm in residential area and all the road rainfall in commercial and industrial areas should be collected and treated accordingly before direct discharge or utilization. Based on the strong correlation between COD and TSS (R2, 0.87-0.95) and the low biodegradation capacity (biochemical oxygen demand BOD5/COD < 0.3), a sedimentation process and an effective filtration system composed of soil and slag were designed to treat the initial rainwater, which could remove over 90% of the pollutant loads. The above results may help to develop better rainwater utilization and pollution control strategies for cities with water shortages.

  10. On-Road Validation of a Simplified Model for Estimating Real-World Fuel Economy: Preprint

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wood, Eric; Gonder, Jeff; Jehlik, Forrest

    On-road fuel economy is known to vary significantly between individual trips in real-world driving conditions. This work introduces a methodology for rapidly simulating a specific vehicle's fuel economy over the wide range of real-world conditions experienced across the country. On-road test data collected using a highly instrumented vehicle is used to refine and validate this modeling approach. Model accuracy relative to on-road data collection is relevant to the estimation of 'off-cycle credits' that compensate for real-world fuel economy benefits that are not observed during certification testing on a chassis dynamometer.

  11. On-Road Validation of a Simplified Model for Estimating Real-World Fuel Economy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wood, Eric; Gonder, Jeffrey; Jehlik, Forrest

    On-road fuel economy is known to vary significantly between individual trips in real-world driving conditions. This work introduces a methodology for rapidly simulating a specific vehicle's fuel economy over the wide range of real-world conditions experienced across the country. On-road test data collected using a highly instrumented vehicle is used to refine and validate this modeling approach. Here, model accuracy relative to on-road data collection is relevant to the estimation of 'off-cycle credits' that compensate for real-world fuel economy benefits that are not observed during certification testing on a chassis dynamometer.

  12. On-Road Validation of a Simplified Model for Estimating Real-World Fuel Economy

    DOE PAGES

    Wood, Eric; Gonder, Jeffrey; Jehlik, Forrest

    2017-03-28

    On-road fuel economy is known to vary significantly between individual trips in real-world driving conditions. This work introduces a methodology for rapidly simulating a specific vehicle's fuel economy over the wide range of real-world conditions experienced across the country. On-road test data collected using a highly instrumented vehicle is used to refine and validate this modeling approach. Here, model accuracy relative to on-road data collection is relevant to the estimation of 'off-cycle credits' that compensate for real-world fuel economy benefits that are not observed during certification testing on a chassis dynamometer.

  13. Modeling the Blast Load Simulator Airblast Environment using First Principles Codes. Report 1, Blast Load Simulator Environment

    DTIC Science & Technology

    2016-11-01

    ER D C/ G SL T R- 16 -3 1 Modeling the Blast Load Simulator Airblast Environment Using First Principles Codes Report 1, Blast Load...Simulator Airblast Environment using First Principles Codes Report 1, Blast Load Simulator Environment Gregory C. Bessette, James L. O’Daniel...evaluate several first principles codes (FPCs) for modeling airblast environments typical of those encountered in the BLS. The FPCs considered were

  14. Electric-car simulation

    NASA Technical Reports Server (NTRS)

    Chapman, C. P.; Slusser, R. A.

    1980-01-01

    PARAMET, interactive simulation program for parametric studies of electric vehicles, guides user through simulation by menu and series of prompts for input parameters. Program considers aerodynamic drag, rolling resistance, linear and rotational acceleration, and road gradient as forces acting on vehicle.

  15. Seat belt pre-pretensioner effect on child-sized dummies during run-off-road events.

    PubMed

    Stockman, Isabelle; Bohman, Katarina; Jakobsson, Lotta

    2017-05-29

    Run-off-road events occur frequently and can result in severe consequences. Several potential injury-causing mechanisms can be observed in the diverse types of run-off-road events. Real-world data show that different types of environments, such as rough terrain, ditch types, and whether multiple events occur, may be important contributing factors to occupant injury. Though countermeasures addressing front seat occupants have been presented, studies on rear seat occupant retention in situations such as run-off-road events are lacking. The aim of this study was to investigate the seat belt pre-pretensioner effect on rear-seated child-sized anthropomorphic test devices (ATDs) during 2 different types of run-off-road events. The study was carried out using 2 test setups: a rig test with a vehicle rear seat mounted on a multi-axial robot simulating a road departure event into a side ditch and an in-vehicle test setup with a Volvo XC60 entering a side ditch with a grass slope, driving inside the ditch, and returning back to the road from the ditch. Potential subsequent rollovers or impacts were not included in the test setups. Three different ATDs were used. The Q6 and Q10 were seated on an integrated booster cushion and the Hybrid III (HIII) 5th percentile female was positioned directly on the seat. The seat belt retractor was equipped with a pre-pretensioner (electrical reversible retractor) with 3 force level settings. In addition, reference tests with the pre-pretensioner inactivated were run. Kinematics and the shoulder belt position were analyzed. In rig tests, the left-seated ATD was exposed to rapid inboard lateral loads relative to the vehicle. The displacement for each ATD was reduced when the pre-pretensioner was activated compared to tests when it was inactivated. Maximum inboard displacement occurred earlier in the event for all ATDs when the pre-pretensioner was activated. Shoulder belt slip-off occurred for the Q6 and Q10 in tests where the pre-pretensioner was inactivated. During in-vehicle tests, the left-seated ATD was exposed to an inboard movement when entering the road again after driving in the ditch. The maximum inboard head displacement was reduced in tests where the pre-pretensioner was activated compared to tests in which it was inactivated. During both test setups, the activation of the pre-pretensioner resulted in reduced lateral excursion of the Q6, Q10, and HIII 5th percentile female due to the shoulder belt remaining on the shoulder and supporting the side of the lower torso. The results provide new insights into the potential benefits of using a pre-pretensioner to reduce kinematic responses during complex run-off-road events through supporting the seat belt to remain on the shoulder. This study addresses potential countermeasures to improve real-world protection of rear-seated children, and it provides a broader perspective including the influence of precrash kinematics.

  16. Simulating Deforestation and Carbon Loss in Amazonia: Impacts in Brazil's Roraima State from Reconstructing Highway BR-319 (Manaus-Porto Velho)

    NASA Astrophysics Data System (ADS)

    Barni, Paulo Eduardo; Fearnside, Philip Martin; Graça, Paulo Maurício Lima de Alencastro

    2015-02-01

    Reconstruction of Highway BR-319 (Manaus-Porto Velho) would allow for access from the "arc of deforestation" in the southern part of Brazil's Amazon region to vast blocks of forests in central and northern Amazonia. Building roads is known to be a major driver of deforestation, allowing entry of squatters, and other actors. Rather than deforestation along the highway route, here we consider the road's potential for stimulating deforestation in a separate location, approximately 550 km north of BR-319's endpoint in Manaus. Reconstructing BR-319 has great potential impact to start a new wave of migration to this remote region. The southern portion of the state of Roraima, the focus of our study, is already connected to Manaus by Highway BR-174. We modeled deforestation in southern Roraima and simulated carbon emissions between 2007 and 2030 under four scenarios. Simulations used the AGROECO model in DINAMICA-EGO software. Two scenarios were considered with reconstruction of BR-319 and two without this road connection. For each of the two possibilities regarding BR-319, simulations were developed for (1) a "conservation" (CONSERV) scenario that assumes the creation of a series of protected areas, and (2) a "business-as-usual" (BAU) scenario that assumes no additional protected areas. Results show that by 2030, with BR-319 rebuilt, deforestation carbon emissions would increase between 19 % (CONSERV) and 42 % (BAU) over and above those corresponding to no-road scenarios.

  17. Simulating deforestation and carbon loss in Amazonia: impacts in Brazil's Roraima state from reconstructing Highway BR-319 (Manaus-Porto Velho).

    PubMed

    Barni, Paulo Eduardo; Fearnside, Philip Martin; Graça, Paulo Maurício Lima de Alencastro

    2015-02-01

    Reconstruction of Highway BR-319 (Manaus-Porto Velho) would allow for access from the "arc of deforestation" in the southern part of Brazil's Amazon region to vast blocks of forests in central and northern Amazonia. Building roads is known to be a major driver of deforestation, allowing entry of squatters, and other actors. Rather than deforestation along the highway route, here we consider the road's potential for stimulating deforestation in a separate location, approximately 550 km north of BR-319's endpoint in Manaus. Reconstructing BR-319 has great potential impact to start a new wave of migration to this remote region. The southern portion of the state of Roraima, the focus of our study, is already connected to Manaus by Highway BR-174. We modeled deforestation in southern Roraima and simulated carbon emissions between 2007 and 2030 under four scenarios. Simulations used the AGROECO model in DINAMICA-EGO © software. Two scenarios were considered with reconstruction of BR-319 and two without this road connection. For each of the two possibilities regarding BR-319, simulations were developed for (1) a "conservation" (CONSERV) scenario that assumes the creation of a series of protected areas, and (2) a "business-as-usual" (BAU) scenario that assumes no additional protected areas. Results show that by 2030, with BR-319 rebuilt, deforestation carbon emissions would increase between 19% (CONSERV) and 42% (BAU) over and above those corresponding to no-road scenarios.

  18. Chasing the silver bullet: measuring driver fatigue using simple and complex tasks.

    PubMed

    Baulk, S D; Biggs, S N; Reid, K J; van den Heuvel, C J; Dawson, D

    2008-01-01

    Driver fatigue remains a significant cause of motor-vehicle accidents worldwide. New technologies are increasingly utilised to improve road safety, but there are no effective on-road measures for fatigue. While simulated driving tasks are sensitive, and simple performance tasks have been used in industrial fatigue management systems (FMS) to quantify risk, little is known about the relationship between such measures. Establishing a simple, on-road measure of fatigue, as a fitness-to-drive tool, is an important issue for road safety and accident prevention, particularly as many fatigue related accidents are preventable. This study aimed to measure fatigue-related performance decrements using a simple task (reaction time - RT) and a complex task (driving simulation), and to determine the potential for a link between such measures, thus improving FMS success. Fifteen volunteer participants (7 m, 8 f) aged 22-56 years (mean 33.6 years), underwent 26 h of supervised wakefulness before an 8h recovery sleep opportunity. Participants were tested using a 30-min interactive driving simulation test, bracketed by a 10-min psychomotor vigilance task (PVT) at 4, 8, 18 and 24h of wakefulness, and following recovery sleep. Extended wakefulness caused significant decrements in PVT and driving performance. Although these measures are clearly linked, our analyses suggest that driving simulation cannot be replaced by a simple PVT. Further research is needed to closely examine links between performance measures, and to facilitate accurate management of fitness to drive, which requires more complex assessments of performance than RT alone.

  19. A spatial DB model to simulate the road network efficiency in hydrogeological emergency

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Michele, Mangiameli, E-mail: michele.mangiameli@dica.unict.it; Giuseppe, Mussumeci

    We deal with the theme of the simulation of risk analysis using a technological approach based on the integration of exclusively free and open source tools: PostgreSQL as Database Management System (DBMS) and Quantum GIS-GRASS as Geographic Information System (GIS) platform. The case study is represented by a seismic land in Sicily characterized by steep slopes and frequent instability phenomena. This area includes a city of about 30.000 inhabitants (Enna) that lies on the top of a mountain at about 990 m a.s.l.. The access to the city is assured by few and very winding roads that are also highly vulnerablemore » to seismic and hydrogeological hazards. When exceptional rainfall events occur, the loss of efficiency of these roads should compromise timeliness and effectiveness of rescue operations. The data of the sample area have been structured into the adopted DBMS, and the connection to the GIS functionalities allows simulating the exceptional events. We analyzed the hazard, vulnerability and exposure related to these events and calculated the final risk defining three classes for each scenario: low (L), medium (M) and high (H). This study can be a valuable tool to prioritize risk levels and set priorities for intervention to the main road networks.« less

  20. A spatial DB model to simulate the road network efficiency in hydrogeological emergency

    NASA Astrophysics Data System (ADS)

    Michele, Mangiameli; Giuseppe, Mussumeci

    2015-12-01

    We deal with the theme of the simulation of risk analysis using a technological approach based on the integration of exclusively free and open source tools: PostgreSQL as Database Management System (DBMS) and Quantum GIS-GRASS as Geographic Information System (GIS) platform. The case study is represented by a seismic land in Sicily characterized by steep slopes and frequent instability phenomena. This area includes a city of about 30.000 inhabitants (Enna) that lies on the top of a mountain at about 990 m a.s.l.. The access to the city is assured by few and very winding roads that are also highly vulnerable to seismic and hydrogeological hazards. When exceptional rainfall events occur, the loss of efficiency of these roads should compromise timeliness and effectiveness of rescue operations. The data of the sample area have been structured into the adopted DBMS, and the connection to the GIS functionalities allows simulating the exceptional events. We analyzed the hazard, vulnerability and exposure related to these events and calculated the final risk defining three classes for each scenario: low (L), medium (M) and high (H). This study can be a valuable tool to prioritize risk levels and set priorities for intervention to the main road networks..

  1. 6. GENERAL WIDE VIEW SHOWING EAST (SOUTHEAST) SIDE, LOOKING WEST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. GENERAL WIDE VIEW SHOWING EAST (SOUTHEAST) SIDE, LOOKING WEST ACROSS TURNING BASIN; FREIGHTER LOADING IN FOREGROUND - Oakland Army Base, Transit Shed, East of Dunkirk Street & South of Burma Road, Oakland, Alameda County, CA

  2. 5. GENERAL VIEW SHOWING ORIGINAL SETTING AT WHARFSIDE WITH CONTAINERIZED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. GENERAL VIEW SHOWING ORIGINAL SETTING AT WHARFSIDE WITH CONTAINERIZED FREIGHT LOADING EQUIPMENT AT PORT OF OAKLAND FACILITY - Oakland Army Base, Transit Shed, East of Dunkirk Street & South of Burma Road, Oakland, Alameda County, CA

  3. 40 CFR 230.60 - General evaluation of dredged or fill material.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... generally found in areas of high current or wave energy such as streams with large bed loads or coastal... show watercourses, surface relief, proximity to tidal movement, private and public roads, location of...

  4. 40 CFR 230.60 - General evaluation of dredged or fill material.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... generally found in areas of high current or wave energy such as streams with large bed loads or coastal... show watercourses, surface relief, proximity to tidal movement, private and public roads, location of...

  5. 40 CFR 230.60 - General evaluation of dredged or fill material.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... generally found in areas of high current or wave energy such as streams with large bed loads or coastal... show watercourses, surface relief, proximity to tidal movement, private and public roads, location of...

  6. 40 CFR 230.60 - General evaluation of dredged or fill material.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... generally found in areas of high current or wave energy such as streams with large bed loads or coastal... show watercourses, surface relief, proximity to tidal movement, private and public roads, location of...

  7. 40 CFR 230.60 - General evaluation of dredged or fill material.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... generally found in areas of high current or wave energy such as streams with large bed loads or coastal... show watercourses, surface relief, proximity to tidal movement, private and public roads, location of...

  8. Load response instrumentation of SHRP pavement : research implementation plan.

    DOT National Transportation Integrated Search

    2006-12-07

    As part of its support for the Strategic Highway Research Program (SHRP), the Ohio Department of Transportation, : in conjunction with the Federal Highway Administration constructed a comprehensive test road encompassing four : of nine experiments in...

  9. Why does LTPP require site-specific traffic loading data?

    DOT National Transportation Integrated Search

    2013-01-01

    This flyer summarizes recent documents and training materials concerning road weather management and surface transportation published since June 2011. It includes reports, flyers, pamphlets, and training courses to show the progress made in the manag...

  10. Looking Northeast in Oxide Building at Reactors on Second Floor ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking Northeast in Oxide Building at Reactors on Second Floor Including Reactor One (Left) and Reactor Two (Right) - Hematite Fuel Fabrication Facility, Oxide Building & Oxide Loading Dock, 3300 State Road P, Festus, Jefferson County, MO

  11. Analysis of permit vehicle loads in Wisconsin.

    DOT National Transportation Integrated Search

    2009-09-30

    This study evaluated the impact of the 250-kip Wisconsin Standard Permit Vehicle against the overloaded vehicles operating on Wisconsin roads in recent years. The evaluation was conducted using three sets of data: 1) overloaded vehicle records within...

  12. DETAIL OF WEST END SLIDING DOOR AND EAVE VENTS ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF WEST END SLIDING DOOR AND EAVE VENTS ON THE SOUTH SIDE - Hickam Field, Practice Bomb Loading Shed, Bomb Storage Road near the intersection of Moffet and Kamakahi Streets, Honolulu, Honolulu County, HI

  13. 7. VIEW SOUTHEAST, SHOWING WEST SIDE FROM LAND, WITH WASTE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. VIEW SOUTHEAST, SHOWING WEST SIDE FROM LAND, WITH WASTE PAPER BUNDLED ON DOCK, AWAITING LOADING ONTO ODIGITRIA B - Connecticut State Pier, State Pier Road at Thames River, New London, New London County, CT

  14. Investigation of Noise and Vibration in Tires Through Analytical Modeling, Tests and Simulations

    NASA Astrophysics Data System (ADS)

    Cao, Rui

    Tire noise and vibration is an interesting topic, with more and more people paying attention to this issue. Tire noise can both propagate into the vehicle interior and radiate directly toward the immediate environment. Tire noise is not only related to vehicle passengers' comfort but also affects the residential or working area near highways, especially in high population density regions. The emerging electric vehicles also emphasize tires' role in vehicle Noise Vibration and Harshness (NVH) since power-train noises are significantly reduced. The study in this research focuses on the noise and vibration of tires from the low to high frequency range, typically from 60 kHz to 2 kHz. From the analytical point of view, forced vibration of a fully coupled 2D structural-acoustical model is presented and a 3D structural model is also investigated for various input conditions. Both circumferential and cross-sectional shearing motions in the analytical tire models can be observed. Static tire surface mobilities were also measured to verify the findings from the developed models. On the experimental side, the loading effect on tire noise radiation was studied, where applied loads ranged from 500 lbs to 1300 lbs. Results indicate that sound radiation is usually proportional to the loading, except between 1.1 kHz to 1.7 kHz where the load-noise relation is reversed. In addition, tire noise generated by road surface discontinuities was also studied experimentally. As expected, a broadband increase of the noise spectrum can be observed below 1 kHz compared to the noise on a continuous surface. However, the difference tends to diminish above 1 kHz except in a certain narrow frequency band depending on the particular tire tested. High frequency waves and motions in tire cross-sectional directions were identified as occurring in the frequency range of interest. A two-dimensional cross-sectional analytical tire model was proposed for further investigations, in order to verify the relation among high frequency tire noise properties and the fast propagating waves and cross-sectional motions in tires. Finally, a fully coupled finite element tire-wheel model was developed to simulate the tire deformation under static vertical loading and to explore the influence of various excitation forces. The forces or accelerations, depending on the boundary conditions, at the wheel center can be calculated from the tire model up to 500 Hz. The results can be potentially used as input for vehicle full body simulations, thus accelerating the optimization process of new product development.

  15. Environmental determinants of celeration behaviour.

    PubMed

    af Wåhlberg, Anders E

    2015-01-01

    Celeration (speed change) behaviour of drivers has been posited to be the best predictor of their traffic accident involvement. The origins of this behaviour, however, have not been specified. A model is therefore introduced, where celeration is partly due to the individual disposition of the driver (i.e., driving style), and partly to the environment (road layout, rules and traffic density). Three measurement problems for celeration were studied; the effect of traffic density, of regular versus irregular routes, and weight of the vehicle (loaded/unloaded) on celeration behaviour. Two small samples of truck drivers in Sweden were measured for several months each. There was a strong effect of vehicle load, with behaviour being more cautious with increased weight. Driving on different roads also yielded differences in behaviour, although the design used did not permit conclusions about what caused these. Traffic volume was not found to have any reliable effect on celeration.

  16. Potential occupant injury reduction in the U.S. vehicle fleet for lane departure warning-equipped vehicles in single-vehicle crashes.

    PubMed

    Kusano, Kristofer; Gorman, Thomas I; Sherony, Rini; Gabler, Hampton C

    2014-01-01

    Single-vehicle collisions involve only 10 percent of all occupants in crashes in the United States, yet these same crashes account for 31 percent of all fatalities. Along with other vehicle safety advancements, lane departure warning (LDW) systems are being introduced to mitigate the harmful effects of single-vehicle collisions. The objective of this study is to quantify the number of crashes and seriously injured drivers that could have been prevented in the United States in 2012 had all vehicles been equipped with LDW. In order to estimate the potential injury reduction benefits of LDW in the vehicle fleet, a comprehensive crash and injury simulation model was developed. The model's basis was 481 single-vehicle collisions extracted from the NASS-CDS for year 2012. Each crash was simulated in 2 conditions: (1) as it occurred and (2) as if the driver had an LDW system. By comparing the simulated vehicle's off-road trajectory before and after LDW, the reduction in the probability of a crash was determined. The probability of a seriously injured occupant (Maximum Abbreviated Injury Score [MAIS] 3+) given a crash was computed using injury risk curves with departure velocity and seat belt use as predictors. Each crash was simulated between 18 and 216 times to account for variable driver reaction, road, and vehicle conditions. Finally, the probability of a crash and seriously injured driver was summed over all simulations to determine the benefit of LDW. A majority of roads where departure crashes occurred had 2 lanes and were undivided. As a result, 58 percent of crashes had no shoulder. LDW will not be as effective on roads with no shoulder as on roads with large shoulders. LDW could potentially prevent 28.9 percent of all road departure crashes caused by the driver drifting out of his or her lane, resulting in a 24.3 percent reduction in the number of seriously injured drivers. The results of this study show that LDW, if widely adopted, could significantly mitigate a harmful crash type. Larger shoulder width and the presence of lane markings, determined by manual examination of scene photographs, increased the effectiveness of LDW. This result suggests that highway systems should be modified to maximize LDW effectiveness by expanding shoulders and regularly painting lane lines.

  17. 1. NEUTRAL BUOYANCY SIMULATOR BUILDING (NBS) EXTERIOR ELEVATION LOOKING NORTH; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. NEUTRAL BUOYANCY SIMULATOR BUILDING (NBS) EXTERIOR ELEVATION LOOKING NORTH; TANK BUILDING TO LEFT, CONTROL ROOM ETC. TO RIGHT OF CONNECTING BAY. - Marshall Space Flight Center, Neutral Buoyancy Simulator Facility, Rideout Road, Huntsville, Madison County, AL

  18. Survey of the Influence of the Width of Urban Branch Roads on the Meeting of Two-Way Vehicle Flows

    PubMed Central

    Chen, Qun; Zhao, Yunan; Pan, Shuangli; Wang, Yan

    2016-01-01

    Branch roads, which are densely distributed in cities, allow for the flow of local traffic and provide connections between the city and outlying areas. Branch roads are typically narrow, and two-way traffic flows on branch roads are thus affected when vehicles traveling in opposite directions meet. This study investigates the changes in the velocities of vehicles when they meet on two-way branch roads. Various widths of branch roads were selected, and their influence on traffic flows was investigated via a video survey. The results show that, depending on the average vehicle velocity, branch roads require different widths to prevent a large decrease in velocity when vehicles meet. When the velocity on a branch road is not high (e.g., the average velocity without meeting is approximately 6 m/s), appropriately increasing the road width will notably increase the meeting velocity. However, when the velocity is high (e.g., the average velocity without meeting is greater than 10 m/s), there is a large decrease in velocity when meeting even if the road surface is wide (6.5 m). This study provides a basis for selecting the width of urban branch roads and the simulation of bidirectional traffic on such roads. PMID:26881427

  19. Methods to improve traffic flow and noise exposure estimation on minor roads.

    PubMed

    Morley, David W; Gulliver, John

    2016-09-01

    Address-level estimates of exposure to road traffic noise for epidemiological studies are dependent on obtaining data on annual average daily traffic (AADT) flows that is both accurate and with good geographical coverage. National agencies often have reliable traffic count data for major roads, but for residential areas served by minor roads, especially at national scale, such information is often not available or incomplete. Here we present a method to predict AADT at the national scale for minor roads, using a routing algorithm within a geographical information system (GIS) to rank roads by importance based on simulated journeys through the road network. From a training set of known minor road AADT, routing importance is used to predict AADT on all UK minor roads in a regression model along with the road class, urban or rural location and AADT on the nearest major road. Validation with both independent traffic counts and noise measurements show that this method gives a considerable improvement in noise prediction capability when compared to models that do not give adequate consideration to minor road variability (Spearman's rho. increases from 0.46 to 0.72). This has significance for epidemiological cohort studies attempting to link noise exposure to adverse health outcomes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Survey of the Influence of the Width of Urban Branch Roads on the Meeting of Two-Way Vehicle Flows.

    PubMed

    Chen, Qun; Zhao, Yunan; Pan, Shuangli; Wang, Yan

    2016-01-01

    Branch roads, which are densely distributed in cities, allow for the flow of local traffic and provide connections between the city and outlying areas. Branch roads are typically narrow, and two-way traffic flows on branch roads are thus affected when vehicles traveling in opposite directions meet. This study investigates the changes in the velocities of vehicles when they meet on two-way branch roads. Various widths of branch roads were selected, and their influence on traffic flows was investigated via a video survey. The results show that, depending on the average vehicle velocity, branch roads require different widths to prevent a large decrease in velocity when vehicles meet. When the velocity on a branch road is not high (e.g., the average velocity without meeting is approximately 6 m/s), appropriately increasing the road width will notably increase the meeting velocity. However, when the velocity is high (e.g., the average velocity without meeting is greater than 10 m/s), there is a large decrease in velocity when meeting even if the road surface is wide (6.5 m). This study provides a basis for selecting the width of urban branch roads and the simulation of bidirectional traffic on such roads.

  1. Virtual Road Safety Audits: Recommended Procedures for Using Driving Simulation and Technology to Expand Existing Practices

    DOT National Transportation Integrated Search

    2018-02-02

    One approach that has been proposed to address the limitations of the current reactive safetymonitoring approaches is the use of road safety audits (RSAs). As part of an RSA, the existing or expected characteristics and traffic conditions of a locati...

  2. Effects of roadway configurations on near-road air quality and the implications on roadway designs

    EPA Science Inventory

    This paper presents an analysis of wind tunnel experiments of twelve different roadway configurations and modeling of these configurations using a Large-Eddy Simulation (LES) model, aiming at investigating how flow structures affect the impact of roadway features on near-road and...

  3. Organic Carbon Trends, Loads, and Yields to the Sacramento-San Joaquin Delta, California, Water Years 1980 to 2000

    USGS Publications Warehouse

    Saleh, Dina K.; Domagalski, Joseph L.; Kratzer, Charles R.; Knifong, Donna L.

    2003-01-01

    Organic carbon, nutrient, and suspended sediment concentration data were analyzed for the Sacramento and San Joaquin River Basins for the period 1980-2000. The data were retrieved from three sources: the U.S. Geological Survey's National Water Information System, the U.S. Environmental Protection Agency's Storage and Retrieval System, and the California Interagency Ecological Program's relational database. Twenty sites were selected, all of which had complete records of daily streamflow data. These data met the minimal requirements of the statistical programs used to estimate trends, loads, and yields. The seasonal Kendall program was used to estimate trends in organic carbon, nutrient, and suspended sediment. At all 20 sites, analyses showed that in the 145 analyses for the seven constituents, 95 percent of the analyses had no significant trend. Dissolved organic carbon (DOC) concentrations were significant only for four sites: the American River at Sacramento, the Sacramento River sites near Freeport, Orestimba Creek at River Roads near Crows Landing, and the San Joaquin River near Vernalis. Loads were calculated using two programs, ESTIMATOR and LOADEST2. The 1998 water year was selected to describe loads in the Sacramento River Basin. Organic carbon, nutrient, and suspended sediment loads at the Sacramento River sites near Freeport included transported loads from two main upstream sites: the Sacramento River at Verona and the American River at Sacramento. Loads in the Sacramento River Basin were affected by the amount of water diverted to the Yolo Bypass (the amount varies annually, depending on the precipitation and streamflow). Loads at the Sacramento River sites near Freeport were analyzed for two hydrologic seasons: the irrigation season (April to September) and the nonirrigation season (October to March). DOC loads are lower during the irrigation season then they are during the nonirrigation season. During the irrigation season, water with low concentrations of DOC is released from reservoirs and used for irrigation. On the other hand, during the nonirrigation season, streamflow results from surface water runoff and has higher concentrations of organic carbon, nutrients, and suspended sediment. The 1986 and 1987 water years were selected to describe loads in the San Joaquin River Basin. Organic carbon, nutrient, and suspended sediment loads in the San Joaquin River near Vernalis included transported loads from upstream sites, such as the Mud and Salt Sloughs, the Merced River at River Roads Bridge near Newman, the Tuolumne River at Modesto, and the Stanislaus River at Ripon. Loads at the San Joaquin River near Vernalis also were analyzed for the two seasons. The DOC load for the San Joaquin River at Vernalis is slightly higher during the irrigation season. Yields were calculated in an attempt to rank the subbasins in the Sacramento and San Joaquin River Basins. Five sites delivered streamflow from agricultural and urban sources that had relatively high yields of organic carbon: Sacramento Slough near Knights Landing, Arcade Creek near Del Paso Heights, Salt Slough, Mud Slough, and Colusa Basin Drain at Road 99E near Knights Landing.

  4. Progress on advanced dc and ac induction drives for electric vehicles

    NASA Technical Reports Server (NTRS)

    Schwartz, H. J.

    1982-01-01

    Progress is reported in the development of complete electric vehicle propulsion systems, and the results of tests on the Road Load Simulator of two such systems representative of advanced dc and ac drive technology are presented. One is the system used in the DOE's ETV-1 integrated test vehicle which consists of a shunt wound dc traction motor under microprocessor control using a transistorized controller. The motor drives the vehicle through a fixed ratio transmission. The second system uses an ac induction motor controlled by transistorized pulse width modulated inverter which drives through a two speed automatically shifted transmission. The inverter and transmission both operate under the control of a microprocessor. The characteristics of these systems are also compared with the propulsion system technology available in vehicles being manufactured at the inception of the DOE program and with an advanced, highly integrated propulsion system upon which technology development was recently initiated.

  5. Magnetic biomonitoring of roadside tree leaves: identification of spatial and temporal variations in vehicle-derived particulates

    NASA Astrophysics Data System (ADS)

    Matzka, J.; Maher, B. A.

    We report here the novel use of rapid and non-destructive magnetic measurements to investigate the spatial and temporal pattern of urban dust loadings on leaves of roadside trees. More than 600 leaves were collected from birch trees and their remanent magnetization (IRM 300 mT ) determined and normalized for the leaf area. The results show that this normalised 2-D magnetization is dominantly controlled by the tree's distance to the road. The magnetic analyses enabled detailed mapping of the spatial and temporal variations of vehicle-derived particulates. Higher 2D-magnetizations, indicating higher magnetic dust loadings, were measured for leaves collected adjacent to uphill road sections than for those next to downhill sections. This suggests that vehicle emissions, rather than friction wear or resuspended road dust, are the major source of the roadside magnetic particles. Additional magnetic analyses suggest that the particle size of the magnetic grains dominantly falls in the range classified for airborne particulate matter as PM 2.5 (<2.5 μm), a particle size hazardous to health due to its capacity to be respired deeply into the lungs. Thus, the leaf magnetizations relate directly to release into the atmosphere of harmful vehicle combustion products. For leaves from individual trees, magnetization values fall significantly from high values proximal to the roadside to lower values at the distal side, confirming the ability of trees to reduce aerosol concentrations in the atmosphere. Magnetic analysis of leaves over days and weeks shows that rainfall produces a net decrease in the leaf magnetic loadings.

  6. Two modes of the silk road pattern and their interannual variability simulated by LASG/IAP AGCM SAMIL2.0

    NASA Astrophysics Data System (ADS)

    Song, Fengfei; Zhou, Tianjun; Wang, Lu

    2013-05-01

    In this study, two modes of the Silk Road pattern were investigated using NCEP2 reanalysis data and the simulation produced by Spectral Atmospheric Circulation Model of IAP LASG, Version 2 (SAMIL2.0) that was forced by SST observation data. The horizontal distribution of both modes were reasonably reproduced by the simulation, with a pattern correlation coefficient of 0.63 for the first mode and 0.62 for the second mode. The wave train was maintained by barotropic energy conversion (denoted as CK) and baroclinic energy conversion (denoted as CP) from the mean flow. The distribution of CK was dominated by its meridional component (CK y ) in both modes. When integrated spatially, CK y was more efficient than its zonal component (CK x ) in the first mode but less in the second mode. The distribution and efficiency of CK were not captured well by SAMIL2.0. However, the model performed reasonably well at reproducing the distribution and efficiency of CP in both modes. Because CP is more efficient than CK, the spatial patterns of the Silk Road pattern were well reproduced. Interestingly, the temporal phase of the second mode was well captured by a single-member simulation. However, further analysis of other ensemble runs demonstrated that the successful reproduction of the temporal phase was a result of internal variability rather than a signal of SST forcing. The analysis shows that the observed temporal variations of both CP and CK were poorly reproduced, leading to the low accuracy of the temporal phase of the Silk Road pattern in the simulation.

  7. Effect of simulator training on driving after stroke: a randomized controlled trial.

    PubMed

    Akinwuntan, A E; De Weerdt, W; Feys, H; Pauwels, J; Baten, G; Arno, P; Kiekens, C

    2005-09-27

    Neurologically impaired persons seem to benefit from driving-training programs, but there is no convincing evidence to support this notion. The authors therefore investigated the effect of simulator-based training on driving after stroke. Eighty-three first-ever subacute stroke patients entered a 5-week 15-hour training program in which they were randomly allocated to either an experimental (simulator-based training) or control (driving-related cognitive tasks) group. Performance in off-road evaluations and an on-road test were used to assess the driving ability of subjects pre- and post-training. Outcome of an official predriving assessment administered 6 to 9 months poststroke was also considered. Both groups significantly improved in a visual and many neuropsychological evaluations and in the on-road test after training. There were no significant differences between both groups in improvements from pre- to post-training except in the "road sign recognition test" in which the experimental subjects improved more. Significant improvements in the three-class decision ("fit to drive," "temporarily unfit to drive," and "unfit to drive") were found in favor of the experimental group post-training. Academic qualification and overall disability together determined subjects that benefited most from the simulator-based driving training. Significantly more experimental subjects (73%) than control subjects (42%) passed the follow-up official predriving assessment and were legally allowed to resume driving. Simulator-based driving training improved driving ability, especially for well educated and less disabled stroke patients. However, the findings of the study may have been modified as a result of the large number of dropouts and the possibility of some neurologic recovery unrelated to training.

  8. Surface effects on dynamic stability and loading during outdoor running using wireless trunk accelerometry.

    PubMed

    Schütte, Kurt H; Aeles, Jeroen; De Beéck, Tim Op; van der Zwaard, Babette C; Venter, Rachel; Vanwanseele, Benedicte

    2016-07-01

    Despite frequently declared benefits of using wireless accelerometers to assess running gait in real-world settings, available research is limited. The purpose of this study was to investigate outdoor surface effects on dynamic stability and dynamic loading during running using tri-axial trunk accelerometry. Twenty eight runners (11 highly-trained, 17 recreational) performed outdoor running on three outdoor training surfaces (concrete road, synthetic track and woodchip trail) at self-selected comfortable running speeds. Dynamic postural stability (tri-axial acceleration root mean square (RMS) ratio, step and stride regularity, sample entropy), dynamic loading (impact and breaking peak amplitudes and median frequencies), as well as spatio-temporal running gait measures (step frequency, stance time) were derived from trunk accelerations sampled at 1024Hz. Results from generalized estimating equations (GEE) analysis showed that compared to concrete road, woodchip trail had several significant effects on dynamic stability (higher AP ratio of acceleration RMS, lower ML inter-step and inter-stride regularity), on dynamic loading (downward shift in vertical and AP median frequency), and reduced step frequency (p<0.05). Surface effects were unaffected when both running level and running speed were added as potential confounders. Results suggest that woodchip trails disrupt aspects of dynamic stability and loading that are detectable using a single trunk accelerometer. These results provide further insight into how runners adapt their locomotor biomechanics on outdoor surfaces in situ. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Modelling and study of active vibration control for off-road vehicle

    NASA Astrophysics Data System (ADS)

    Zhang, Junwei; Chen, Sizhong

    2014-05-01

    In view of special working characteristics and structure, engineering machineries do not have conventional suspension system typically. Consequently, operators have to endure severe vibrations which are detrimental both to their health and to the productivity of the loader. Based on displacement control, a kind of active damping method is developed for a skid-steer loader. In this paper, the whole hydraulic system for active damping method is modelled which include swash plate dynamics model, proportional valve model, piston accumulator model, pilot-operated check valve model, relief valve model, pump loss model, and cylinder model. A new road excitation model is developed for the skid-steer loader specially. The response of chassis vibration acceleration to road excitation is verified through simulation. The simulation result of passive accumulator damping is compared with measurements and the comparison shows that they are close. Based on this, parallel PID controller and track PID controller with acceleration feedback are brought into the simulation model, and the simulation results are compared with passive accumulator damping. It shows that the active damping methods with PID controllers are better in reducing chassis vibration acceleration and pitch movement. In the end, the test work for active damping method is proposed for the future work.

  10. Composite load spectra for select space propulsion structural components

    NASA Technical Reports Server (NTRS)

    Newell, J. F.; Kurth, R. E.; Ho, H.

    1991-01-01

    The objective of this program is to develop generic load models with multiple levels of progressive sophistication to simulate the composite (combined) load spectra that are induced in space propulsion system components, representative of Space Shuttle Main Engines (SSME), such as transfer ducts, turbine blades, and liquid oxygen posts and system ducting. The first approach will consist of using state of the art probabilistic methods to describe the individual loading conditions and combinations of these loading conditions to synthesize the composite load spectra simulation. The second approach will consist of developing coupled models for composite load spectra simulation which combine the deterministic models for composite load dynamic, acoustic, high pressure, and high rotational speed, etc., load simulation using statistically varying coefficients. These coefficients will then be determined using advanced probabilistic simulation methods with and without strategically selected experimental data.

  11. Epic Erosion Along Newly Constructed Roads in Yunnan, China

    NASA Astrophysics Data System (ADS)

    Sidle, R. C.; Kono, Y.; Yamaguchi, T.

    2007-05-01

    The recent expansion and construction of new mountain roads in northwestern Yunnan Province, China, poses problems related to landslides and surface erosion that are impacting the headwaters of three great river systems: the Salween, Mekong, and Yangtze. Many of these newer roads are simply blasted into unstable hillsides with virtually no attention paid to optimal road location, construction practices, and erosion control measures. During summer 2006, seven people traveling in a minivan along a newly constructed road to Weixi were killed by a landslide. A survey conducted along a this 23.5 km road section (4 yr old) in the headwaters of the Mekong River revealed epic levels of landslides and surface erosion. Based on a preliminary survey, the road erosion was categorized as moderately severe, severe, or very severe, and a representative 0.75 to 0.90 km stretch of road was then surveyed for both landslide (based on dimensional analysis) and surface erosion (based on soil pedestal height). Average mass wasting rates (9608 t ha-1yr-1) along the road were more than 13 times higher than surface erosion (720 t ha-1yr-1), even though surface erosion rates are among the highest reported for disturbed lands. Dry ravel constituted a minor proportion of the mass wasting: 4% in the severe erosion section of the road and 0.5-0.6% in the moderately severe and very severe sections. For the very severe erosion road section (6 km long), estimated landslide erosion alone was > 33,000 t ha- 1yr-1, 620 times the average landslide erosion from forest roads built in unstable terrain in western North America. These levels of landslide erosion along the Weixi road are the highest ever documented and are somewhat representative of erosion along new mountain roads in this region of Yunnan. Sediment produced from roads is highly connected to fluvial systems; we estimate that 80-95% of the direct sediment contributions into the headwaters of these rivers are attributable to road erosion and landslides. These epic sediment loads represent cumulative effects that may persist in these important transnational rivers for decades.

  12. Water resources of Monroe County, New York, water years 1989-93, with emphasis on water quality in the Irondequoit Creek Basin; Part 2, Atmospheric deposition, ground water, streamflow, trends in water quality, and chemical loads to Irondequoit Bay

    USGS Publications Warehouse

    Sherwood, Donald A.

    1999-01-01

    Irondequoit Creek, which drains 169 square miles in the eastern part of Monroe County, has been recognized as a source of contaminants that contribute to the eutrophication of Irondequoit Bay on Lake Ontario. The discharge from sewage-treatment plants to the creek and its tributaries was eliminated in 1979 by diversion to another wastewater-treatment facility, but sediment and nonpoint-source pollution remain a concern. This report presents data from five surface-water sites in the Irondequoit Creek basin. Irondequoit Creek at Railroad Mills, East Branch Allen Creek, Allen Creek near Rochester, Irondequoit Creek at Blossom Road, and Irondequoit Creek at Empire Boulevard, to supplement published data from 1984-88. Data from Northrup Creek, which drains 11.7 square miles in western Monroe County, provide information on surface-water quality west of the Genesee River. Also presented are water-level and water-quality data from 12 observation-well sites in Ellison and Powdermill Parks and atmospheric-deposition data from 1 site (Mendon Ponds). Concentrations of several chemical constituents in streams of the Irondequoit Creek basin showed statistically significant trends during 1989-93. Concentrations of total suspended-solids and volatile suspended-solids in Irondequoit Creek at Blossom Road decreased 13.5 and 12.5 percent per year, respectively, and those at Empire Boulevard decreased 33.5 and 22 percent per year, respectively. Concentrations of ammonia plus organic nitrogen increased 17.6 percent per year at one site in the basin, but decreased 8.5 and 22.3 percent per year at two sites. Nitrite plus nitrate decreased at only one site (3.5 percent per year). Concentrations of total phosphorus increased at two sites (about 7 percent per year) and decreased at two other sites (7.6 and 29.9 percent per year), and orthophosphate concentrations increased at one site (10.8 percent per year). Dissolved chloride increased at three sites (1.7 to 10.9 percent per year), and dissolved sulfate decreased at one site (2.1 percent per year) and increased at one site (6.8 percent per year). Median concentrations of constituents were significantly lower in atmospheric deposition than in streamflow, although annual deposition of ammonia nitrogen, nitrite plus nitrate, total phosphorus, and orthophosphate in the basin exceeded the amounts removed by streamflow. Atmospheric deposition of chloride and sulfate, by contrast, represented only 1 and 12 percent, respectively, of the loads transported by Irondequoit Creek (Blossom Road site). Comparison of water-quality data from the Allen Creek site and Irondequoit Creek at Blossom Road from water years 1989-93 with corresponding data from 1984-88 indicates significant changes in median concentrations of several constituents. The concentration of dissolved chloride increased at Blossom Road and was unchanged at Allen Creek, whereas sulfate decreased at both sites. Concentrations of ammonia plus organic nitrogen, and nitrite plus nitrate, were significantly lower during 1989-93 than during 1984-88 at both sites. Total phosphorus concentration was lower during 1984-88 than during 1989-93 at Blossom Road but showed no change at Allen Creek, and orthophosphate concentration for 1989-93 was lower than in 1984-88 at both sites. Comparison of chemical loads in atmospheric deposition also indicates significant changes in many constituents. Five-year-mean loads of sodium, sulfate, and lead in atmospheric deposition for 1989-93 exceeded those for 1984-88, whereas 5-year-mean loads of calcium, magnesium, potassium, chloride, nitrite plus nitrate, ammonia nitrogen, and orthophosphate for 1989-93 were lower than in 1984-88. The changes in surface-water quality resulted from several factors within the basin, including land-use changes, annual and seasonal variations in streamflow, and year-to-year variations in the application of deicing salts on area roads. Statistical analyses of long-term (9 years or more) flow rec

  13. 1. GENERAL VIEW SHOWING NORTHEAST END (FRONT) OF TRANSIT SHED, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. GENERAL VIEW SHOWING NORTHEAST END (FRONT) OF TRANSIT SHED, IN CONTEXT WITH LOADING YARD AND DERRICK, LOOKING WEST - Oakland Army Base, Transit Shed, East of Dunkirk Street & South of Burma Road, Oakland, Alameda County, CA

  14. 7. GENERAL VIEW OF SOUTHEAST SIDE OF SHED, SHOWING ALL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. GENERAL VIEW OF SOUTHEAST SIDE OF SHED, SHOWING ALL EIGHTEEN LOADING BAYS, LOOKING WEST FROM ACROSS TURNING BASIN - Oakland Army Base, Transit Shed, East of Dunkirk Street & South of Burma Road, Oakland, Alameda County, CA

  15. Looking Southwest at First Floor View of Oxide Building Interior ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking Southwest at First Floor View of Oxide Building Interior Including Steam Lines, Weigh and Sample Hood, and Superheater - Hematite Fuel Fabrication Facility, Oxide Building & Oxide Loading Dock, 3300 State Road P, Festus, Jefferson County, MO

  16. Empty backhaul, an opportunity to avoid fuel expended on the road.

    DOT National Transportation Integrated Search

    2009-11-01

    "An effort was undertaken to determine whether or not vehicle telemetry could provide data : which would indicate whether a commercial vehicle was operating under loaded or unloaded conditions. : With a straightforward method for establishing the loa...

  17. 99. LIQUID OXYGEN LINE AND SAMPLING VALVE FOR RAPIDLOAD ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    99. LIQUID OXYGEN LINE AND SAMPLING VALVE FOR RAPID-LOAD ON WEST SIDE OF SKID 9A - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  18. The Simulation Operations Officer in a Sustainment Brigade

    DTIC Science & Technology

    2016-05-17

    want to assist FA57s who will be assigned to sustain- ment brigades in the future and to describe the training exercises and road to war (RTW) that... constructive simulations and knowledge manage- ment (KM). A primary difficulty units may face is how to effectively train a “hyper- modular” formation...integrated into the brigade RTW. Th e FA57 can plan a MCSIT to train the brigade. (See CO M M EN TA RY CO M M EN TA RY 3rd Sustainment Brigade Road to

  19. Traffic simulation in regional modeling : application to interstate infrastructure near the Toledo sea port.

    DOT National Transportation Integrated Search

    2012-06-01

    A small team of university-based transportation system experts and simulation experts has been : assembled to develop, test, and apply an approach to assessing road infrastructure capacity using : micro traffic simulation supported by publically avai...

  20. Driving difficulties of brain-injured drivers in reaction to high-crash-risk simulated road events: a question of impaired divided attention?

    PubMed

    Cyr, Andrée-Ann; Stinchcombe, Arne; Gagnon, Sylvain; Marshall, Shawn; Hing, Malcolm Man-Son; Finestone, Hillel

    2009-05-01

    This study examined the role of impaired divided attention and speed of processing in traumatic brain injury (TBI) drivers in high-crash-risk simulated road events. A total of 17 TBI drivers and 16 healthy participants were exposed to four challenging simulated roadway events to which behavioral reactions were recorded. Participants were also asked to perform a dual task during portions of the driving task, and TBI individuals were administered standard measures of divided attention and reaction time. Results indicated that the TBI group crashed significantly more than controls (p < .05) and that dual-task performance correlated significantly with crash rate (r = .58, p = .05).

  1. Modelling Urban Noise in Citygml Ade: Case of the Netherlands

    NASA Astrophysics Data System (ADS)

    Kumar, K.; Ledoux, H.; Commandeur, T. J. F.; Stoter, J. E.

    2017-10-01

    Road traffic and industrial noise has become a major source of discomfort and annoyance among the residents in urban areas. More than 44 % of the EU population is regularly exposed to road traffic noise levels over 55 dB, which is currently the maximum accepted value prescribed by the Environmental Noise Directive for road traffic noise. With continuously increasing population and number of motor vehicles and industries, it is very unlikely to hope for noise levels to diminish in the near future. Therefore, it is necessary to monitor urban noise, so as to make mitigation plans and to deal with its adverse effects. The 2002/49/EC Environmental Noise Directive aims to determine the exposure of an individual to environmental noise through noise mapping. One of the most important steps in noise mapping is the creation of input data for simulation. At present, it is done semi-automatically (and sometimes even manually) by different companies in different ways and is very time consuming and can lead to errors in the data. In this paper, we present our approach for automatically creating input data for noise simulations. Secondly, we focus on using 3D city models for presenting the results of simulation for the noise arising from road traffic and industrial activities in urban areas. We implemented a few noise modelling standards for industrial and road traffic noise in CityGML by extending the existing Noise ADE with new objects and attributes. This research is a steping stone in the direction of standardising the input and output data for noise studies and for reconstructing the 3D data accordingly.

  2. Effects of road salt on larval amphibian susceptibility to parasitism through behavior and immunocompetence.

    PubMed

    Milotic, Dino; Milotic, Marin; Koprivnikar, Janet

    2017-08-01

    Large quantities of road salts are used for de-icing in temperate climates but often leach into aquatic ecosystems where they can cause harm to inhabitants, including reduced growth and survival. However, the implications of road salt exposure for aquatic animal susceptibility to pathogens and parasites have not yet been examined even though infectious diseases can significantly contribute to wildlife population declines. Through a field survey, we found a range of NaCl concentrations (50-560mg/L) in ponds known to contain larval amphibians, with lower levels found in sites close to gravel- rather than hard-surfaced roads. We then investigated how chronic exposure to environmentally-realistic levels of road salt (up to 1140mg/L) affected susceptibility to infection by trematode parasites (helminths) in larval stages of two amphibian species (Lithobates sylvaticus - wood frogs, and L. pipiens - northern leopard frogs) by considering effects on host anti-parasite behavior and white blood cell profiles. Wood frogs exposed to road salt had higher parasite loads, and also exhibited reduced anti-parasite behavior in these conditions. In contrast, infection intensity in northern leopard frogs had a non-monotonic response to road salts even though lymphocytes were only elevated at the highest concentration. Our results indicate the potential for chronic road salt exposure to affect larval amphibian susceptibility to pathogenic parasites through alterations of behavior and immunocompetence, with further studies needed at higher concentrations, as well as that of road salts on free-living parasite infectious stages. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Experimental Studies on Geocells and Mat Systems for Stabilization of Unpaved Shoulders and Temporary Roads

    NASA Astrophysics Data System (ADS)

    Guo, Jun

    Geosynthetics have been used to improve the performance of geomaterials, especially when weak soil exists in roadway applications. In this study, two types of geosynthetic materials, geocell and a mat system, were studied for their applications for unpaved roads and shoulders. The study of geocell was focused on its application for unpaved shoulders. The ability of geocell to improve different geomaterials over intermediate strength subgrade and its possible effect on vegetation were investigated. The study of the mat system was focused on investigating the performance of the mat system over soft and intermediate subgrade with different strengths under cyclic loading to simulate temporary roadway conditions. In the study of geocell for the application for unpaved shoulders, six large scale plate loading tests were conducted on a single type of geocell on target 5% CBR subgrade to investigate the benefits of geocell reinforcement on different base course and topsoil combinations. Different base course and topsoil combinations were investigated including: 200-mm thick unreinforced aggregate, 200-mm thick soil-aggregate mixture (50% aggregate and 50% top soil) with and without geocell reinforcement, 200-mm thick geocell-reinforced topsoil, 50-mm thick aggregate over 150-mm soil-aggregate mixture (50% aggregate and 50% top soil), and 50-mm thick top soil over 150-mm thick geocell-reinforced soil-aggregate mixture (50% aggregate and 50% top soil). Earth pressure cells were install at the interface between subgrade and base course to monitor the load distribution. The cyclic plate loading tests showed that geocell effectively reduced the permanent deformation and the geocell-reinforced soil-aggregate mixture slightly outperformed the unreinforced aggregate at the same thickness. The plate loading tests also suggested the topsoil cover resulted in large permanent deformations. A one-year long outdoor field vegetation test was conducted on base courses with different combinations of aggregate and topsoil including: 200-mm thick unreinforced topsoil, 200-mm thick soil-aggregate mixture (50% aggregate and 50% topsoil), 50-mm thick aggregate over 150-mm soil-aggregate mixture (50% aggregate and 50% topsoil), and 50-mm thick topsoil over 150-mm reinforced soil-aggregate mixture (50% aggregate and 50% topsoil) to investigate the possible effect of geocell on shoulder vegetation established mainly by tall fescue grass and perennial ryegrass. One control (unreinforced) section and one geocell-reinforced section were prepared for each base course combination with a surface area of 1.5 m by 1.5 m. During the one-year test period, soil moisture temperature and volumetric moisture content were monitored. Weather data, such as precipitation and air temperature, were obtain from the nearby weather station at the Lawrence airport. Vegetation growth was evaluated by grass leaf blade length, root length, and grass density. Vegetation biomass was obtained at the end of the test. The test results showed no definite evidence of geocell influencing the vegetation in unpaved shoulders. In the study of the mat system, six large-scale cyclic plate loading tests were conducted on a single type of polyethylene mat system with anchorage to study its performance over soft and intermediate subgrade with the CBR ranging from 1% to 4%. For the comparison purposes, test sections with and without the mat system were prepared and evaluated. For the test section with 1% CBR subgrade, an aggregate base course was used for the test section without the mat system to enable the cyclic plate loading test. The size of the mat system under the investigation was 1.92 m by 1.92 m. A cyclic load at the magnitude of 40 kN was applied through a 300 mm diameter loading plate with a thin rubber pad to simulate a vehicle tire. Earth pressure cells were installed at the interface between the mat system and the subgrade to monitor the load distribution. Loading plate displacements were measured by the displacement transducer inside the actuator. Test results concluded that the mat system was more effective over the intermediate subgrade than the soft subgrade and when large permanent deformations were allowed.

  4. Soldier Mobility: Innovations in Load Carriage System Design and Evaluation (la Mobilite du combattant: innovations dans la conception et l’evaluation des gilets d’intervention)

    DTIC Science & Technology

    2001-05-01

    sweating and inappropriate foot care. Metatarsalgia, stress fractures and knee problems are related primarily to load mass and duration of marching...Stress Fracture 0 1 0 1 1 Other 8 3 1 12 12 Total 68 17 17 102 100 aFrom physician’s assistances at fixed medical sites along the march bFrom medical...feet through physical training and road march practice 2. Reduce load mass Stress Fractures Persistent, boney pain 1. Smoking/tobacco cessation 2. Pre

  5. Analysis of influence of different pressure and different depth of pvd on soft foundation treatment

    NASA Astrophysics Data System (ADS)

    Li, Bin; Wang, XueKui

    2018-02-01

    According to the depth of plastic vertical drainage (pvd), the arrangement mode and the loading mode to analyze the influence of Vacuum preloading near the existing road. An arrangement mode of vacuum preloading to reduce the impact was put forward. The combination of different depth of pvd and loading modes are used to analyze the effect of vacuum preloading treatment and its influence range. The calculations show that the deformation and the influence distance are smaller by using the 40kPa vacuum loading and 41kPa surcharge load preloading. Reducing the depth of the pvd and vacuum combined surcharge preloading can weaken the influence to the existing highway.

  6. 3D-FEM Analysis on Geogrid Reinforced Flexible Pavement Roads

    NASA Astrophysics Data System (ADS)

    Calvarano, Lidia Sarah; Palamara, Rocco; Leonardi, Giovanni; Moraci, Nicola

    2017-12-01

    Nowadays, the need to increase pavement service life, guarantee high performance, reduce service and maintenance costs has been turned a greater attention on the use of reinforcements. This paper presents findings of a numerical investigation on geogrid reinforced flexible pavement roads, under wheel traffic loads, using a three-dimensional Finite Element Method (FEM). The results obtained show the effectiveness of glass fibre grids as reinforcement which, with appropriate design and correct installation, by improving interface shear resistance, can be used to expand the performance of flexible pavements in different ways: by increasing the road service life providing a relevant contribution against superficial rutting or by decreasing the construction costs due to the reduction in the reinforced HMA layer thickness and thus of mineral aggregate required for its construction.

  7. Effective way to reconstruct arch bridges using concrete walls and transverse strands

    NASA Astrophysics Data System (ADS)

    Klusáček, Ladislav; Pěkník, Robin; Nečas, Radim

    2017-09-01

    There are more than 500 masonry arch bridges in the Czech Road system and about 2500 in the Czech Railway system. Many of them are cracked in the longitudinal (span) direction. The barrel vaults are separated by the cracks into partial masonry arches without load bearing connection in transverse direction. These constructions are about 150 years old and they are also too narrow for the current road system. This paper presents a strengthening method for masonry arch bridges using transverse post-tensioning. This method is very useful not only for strengthening in the transverse direction, but widening of masonry arches can be taken as secondary effect especially in case of road bridges. Several bridges were successfully repaired with the use of this system which seems to be effective and reliable.

  8. Autonomous emergency braking systems adapted to snowy road conditions improve drivers' perceived safety and trust.

    PubMed

    Koglbauer, Ioana; Holzinger, Jürgen; Eichberger, Arno; Lex, Cornelia

    2018-04-03

    This study investigated drivers' evaluation of a conventional autonomous emergency braking (AEB) system on high and reduced tire-road friction and compared these results to those of an AEB system adaptive to the reduced tire-road friction by earlier braking. Current automated systems such as the AEB do not adapt the vehicle control strategy to the road friction; for example, on snowy roads. Because winter precipitation is associated with a 19% increase in traffic crashes and a 13% increase in injuries compared to dry conditions, the potential of conventional AEB to prevent collisions could be significantly improved by including friction in the control algorithm. Whereas adaption is not legally required for a conventional AEB system, higher automated functions will have to adapt to the current tire-road friction because human drivers will not be required to monitor the driving environment at all times. For automated driving functions to be used, high levels of perceived safety and trust of occupants have to be reached with new systems. The application case of an AEB is used to investigate drivers' evaluation depending on the road condition in order to gain knowledge for the design of future driving functions. In a driving simulator, the conventional, nonadaptive AEB was evaluated on dry roads with high friction (μ = 1) and on snowy roads with reduced friction (μ = 0.3). In addition, an AEB system adapted to road friction was designed for this study and compared with the conventional AEB on snowy roads with reduced friction. Ninety-six drivers (48 males, 48 females) assigned to 5 age groups (20-29, 30-39, 40-49, 50-59, and 60-75 years) drove with AEB in the simulator. The drivers observed and evaluated the AEB's braking actions in response to an imminent rear-end collision at an intersection. The results show that drivers' safety and trust in the conventional AEB were significantly lower on snowy roads, and the nonadaptive autonomous braking strategy was considered less appropriate on snowy roads compared to dry roads. As expected, the adaptive AEB braking strategy was considered more appropriate for snowy roads than the nonadaptive strategy. In conditions of reduced friction, drivers' subjective safety and trust were significantly improved when driving with the adaptive AEB compared to the conventional AEB. Women felt less safe than men when AEB was braking. Differences between age groups were not of statistical significance. Drivers notice the adaptation of the autonomous braking strategy on snowy roads with reduced friction. On snowy roads, they feel safer and trust the adaptive system more than the nonadaptive automation.

  9. Roadway management plan based on rockfall modelling calibration and validation. Application along the Ma-10 road in Mallorca (Spain)

    NASA Astrophysics Data System (ADS)

    Mateos, Rosa Maria; Garcia, Inmaculada; Reichenbach, Paola; Herrera, Gerardo; Sarro, Roberto; Rius, Joan; Aguilo, Raul

    2016-04-01

    The Tramuntana range, in the northwestern sector of the island of Mallorca (Spain), is frequently affected by rockfalls which have caused significant damage, mainly along the road network. The Ma-10 road constitutes the main transportation corridor on the range with a heavy traffic estimated at 7,200 vehicles per day on average. With a length of 111 km and a tortuous path, the road is the connecting track for 12 municipalities and constitutes a strategic road on the island for many tourist resorts. For the period spanning from 1995 to current times, 63 rockfalls have affected the Ma-10 road with volumes ranging from 0.3m3 to 30,000 m3. Fortunately, no fatalities occurred but numerous blockages on the road took place which caused significant economic losses, valued of around 11 MEuro (Mateos el al., 2013). In this work we present the procedure we have applied to calibrate and validate rockfall modelling in the Tramuntana region, using 103 cases of the available detailed rockfall inventory (Mateos, 2006). We have exploited STONE (Guzzetti et al. 2002), a GIS based rockfall simulation software which computes 2D and 3D rockfall trajectories starting from a DTM and maps of the dynamic rolling friction coefficient and of the normal and tangential energy restitution coefficients. The appropriate identification of these parameters determines the accuracy of the simulation. To calibrate them, we have selected 40 rockfalls along the range which include a wide variety of outcropping lithologies. Coefficients values have been changed in numerous attempts in order to select those where the extent and shape of the simulation matched the field mapping. Best results were summarized with the average statistical values for each parameter and for each geotechnical unit, determining that mode values represent more precisely the data. Initially, for the validation stage, 10 well- known rockfalls exploited in the calibration phase have been selected. Confidence tests have been applied taking into account, not only the success, but also the mistakes. We have further validated the calibrated parameters along the Ma-road using the 63 rockfall recorded during the past 18 years along the road. 81.5% of the rockfalls are well represented by STONE modelling. Results have been exploited by the Road Maintenance Service of Mallorca for the design of the following road management plan: (1) Phase 1. Short-term. Design a specific plan for the road- sections where rockfalls were registered and modelling results were obtained. A large investment will be expended for implementation of retention and protection measures. (2) Phase 2. Medium-term. Design a specific plan for the road- sections where rockfalls were registered but no modelling results were obtained. For these cases, new studies at local scale are necessary as well as the application of other modelling software which include higher resolution input data. (3) Phase 3. Long-term. Design a specific plan for the road- sections where no rockfalls were registered but modelling results were obtained. These are potential rockfall areas and local and specific ground studies are necessaries. References Mateos RM (2006) Los movimientos de ladera en la Serra de Tramuntana (Mallorca). Caracterización geomecánica y análisis de peligrosidad. PhD. Servicio de Publicaciones de la Universidad Complutense de Madrid. Madrid, 299 p. Mateos RM, García-Moreno I, Herrera G, Mulas J (2013) Damage caused by recent mass-movements in Majorca (Spain), a region with a high risk due to tourism.Landslide Science and Practice.Claudio Margottini, Paolo Canuti and KyojiSassa (Editors). Volume 7: Social and Economic Impact and Policies. 105-113. Guzzetti F, Crosta G, Detti R, Agliardi F (2002) STONE: A computer program for the three-dimensional simulation of rock-falls. Computers Geosciences. Vol. 28:1079-1093.

  10. Morphological similarities between DBM and a microeconomic model of sprawl

    NASA Astrophysics Data System (ADS)

    Caruso, Geoffrey; Vuidel, Gilles; Cavailhès, Jean; Frankhauser, Pierre; Peeters, Dominique; Thomas, Isabelle

    2011-03-01

    We present a model that simulates the growth of a metropolitan area on a 2D lattice. The model is dynamic and based on microeconomics. Households show preferences for nearby open spaces and neighbourhood density. They compete on the land market. They travel along a road network to access the CBD. A planner ensures the connectedness and maintenance of the road network. The spatial pattern of houses, green spaces and road network self-organises, emerging from agents individualistic decisions. We perform several simulations and vary residential preferences. Our results show morphologies and transition phases that are similar to Dieletric Breakdown Models (DBM). Such similarities were observed earlier by other authors, but we show here that it can be deducted from the functioning of the land market and thus explicitly connected to urban economic theory.

  11. Vehicle States Observer Using Adaptive Tire-Road Friction Estimator

    NASA Astrophysics Data System (ADS)

    Kwak, Byunghak; Park, Youngjin

    Vehicle stability control system is a new idea which can enhance the vehicle stability and handling in the emergency situation. This system requires the information of the yaw rate, sideslip angle and road friction in order to control the traction and braking forces at the individual wheels. This paper proposes an observer for the vehicle stability control system. This observer consisted of the state observer for vehicle motion estimation and the road condition estimator for the identification of the coefficient of the road friction. The state observer uses 2 degrees-of-freedom bicycle model and estimates the system variables based on the Kalman filter. The road condition estimator uses the same vehicle model and identifies the coefficient of the tire-road friction based on the recursive least square method. Both estimators make use of each other information. We show the effectiveness and feasibility of the proposed scheme under various road conditions through computer simulations of a fifteen degree-of-freedom non-linear vehicle model.

  12. Assessing effects of changing land use practices on sediment loads in Panther Creek, north coastal California

    USGS Publications Warehouse

    Madej, Mary Ann; Bundros, Greg; Klein, Randy

    2011-01-01

    Revisions to the California Forest Practice Rules since 1974 were intended to increase protection of water quality in streams draining timber harvest areas. The effects of improved timber harvesting methods and road designs on sediment loading are assessed for the Panther Creek basin, a 15.4 km2 watershed in Humboldt County, north coastal California. We compute land use statistics, analyze suspended sediment discharge rating curves, and compare sediment yields in Panther Creek to a control (unlogged) stream, Little Lost Man Creek. From 1978 to 2008, 8.2 km2 (over half the watershed) was clearcut and other timber management activities (thinning, selection cuts, and so forth) affected an additional 5.9 km2. Since 1984, 40.7 km of streams in harvest units received riparian buffer strip protection. Between 2000 and 2009, 22 km of roads were upgraded and 9.7 km were decommissioned, reducing potential sediment production by an estimated 40,000 m3. Road density is currently 3.1 km/km2. Sediment rating curves from 2005 to 2010 indicate a decrease in suspended sediment concentrations when compared to the pre-1996 period, although Panther Creek still has a higher sediment yield on a per unit area basis than the control stream.

  13. Characterization of heavy metal desorption from road-deposited sediment under acid rain scenarios.

    PubMed

    Zhao, Bo; Liu, An; Wu, Guangxue; Li, Dunzhu; Guan, Yuntao

    2017-01-01

    Road-deposited sediments (RDS) on urban impervious surfaces are important carriers of heavy metals. Dissolved heavy metals that come from RDS influenced by acid rain, are more harmful to urban receiving water than particulate parts. RDS and its associated heavy metals were investigated at typical functional areas, including industrial, commercial and residential sites, in Guangdong, Southern China, which was an acid rain sensitive area. Total and dissolved heavy metals in five particle size fractions were analyzed using a shaking method under acid rain scenarios. Investigated heavy metals showed no difference in the proportion of dissolved fraction in the solution under different acid rain pHs above 3.0, regardless of land use. Dissolved loading of heavy metals related to organic carbon content were different in runoff from main traffic roads of three land use types. Coarse particles (>150μm) that could be efficiently removed by conventional street sweepers, accounted for 55.1%-47.1% of the total dissolved metal loading in runoff with pH3.0-5.6. The obtained findings provided a significant scientific basis to understand heavy metal release and influence of RDS grain-size distribution and land use in dissolved heavy metal pollution affected by acid rain. Copyright © 2016. Published by Elsevier B.V.

  14. Understanding road surface pollutant wash-off and underlying physical processes using simulated rainfall.

    PubMed

    Egodawatta, Prasanna; Goonetilleke, Ashantha

    2008-01-01

    Pollutant wash-off is one of the key pollutant processes that detailed knowledge is required in order to develop successful treatment design strategies for urban stormwater. Unfortunately, current knowledge relating to pollutant wash-off is limited. This paper presents the outcomes of a detailed investigation into pollutant wash-off on residential road surfaces. The investigations consisted of research methodologies formulated to overcome the physical constraints due to the heterogeneity of urban paved surfaces and the dependency on naturally occurring rainfall. This entailed the use of small road surface plots and artificially simulated rainfall. Road surfaces were selected due to its critical importance as an urban stormwater pollutant source. The study results showed that the influence of initially available pollutants on the wash-off process was limited. Furthermore, pollutant wash-off from road surfaces can be replicated using an exponential equation. However, the typical version of the exponential wash-off equation needs to be modified by introducing a non dimensional factor referred to as 'capacity factor' CF. Three rainfall intensity ranges were identified where the variation of CF can be defined. Furthermore, it was found that particulate density rather than size is the critical parameter that influences the process of pollutant wash-off. (c) IWA Publishing 2008.

  15. Longwall gate road stability in a steeply pitching thick coal seam with a weak roof. Report of investigations/1995

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Barron, L.R.; DeMarco, M.J.

    1995-12-31

    The U.S. Bureau of Mines conducted a ground pressure analysis of a wide abutment-type chain pillar in a two-entry gate road of a Western U.S. coal mine with an extremely weak immediate roof. This report discusses gate road layout and performance and secondary support effectiveness. The results of the pillar pressure study are compared to pillar loading predicted by a widely used pillar design method and to similar studies in other mines. A stability evaluation of the most recent longwall headgate, using the USBM Analysis of Longwall Pillar Stability (ALPS) indicates marginal stability in first-panel mining and instability in second-panelmore » mining. ALPS and the USBM Coal Mine Roof Rating (CMRR) system are used to evaluate tailgate-mining stability of the previous gate roads and to determine pillar and entry width and top coal thickness criteria for tailgate stability in future panels.« less

  16. Texas transportation planning for future renewable energy projects : final report.

    DOT National Transportation Integrated Search

    2017-03-01

    There will be a significant increase in the number of renewable energy production facilities in Texas. The : construction of wind farms requires the transport of wind turbine components that create increased loads on : rural roads and bridges. These ...

  17. 100. INTERIOR OF SKID 9A: VENT VALVE AND RELIEF VALVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    100. INTERIOR OF SKID 9A: VENT VALVE AND RELIEF VALVE FOR RAPID-LOAD LIQUID OXYGEN TANK - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  18. Linear stochastic evaluation of tyre vibration due to tyre/road excitation

    NASA Astrophysics Data System (ADS)

    Rustighi, E.; Elliott, S. J.; Finnveden, S.; Gulyás, K.; Mócsai, T.; Danti, M.

    2008-03-01

    Tyre/road interaction is recognised as the main source of interior and exterior noise for velocities over the 40 km/h. In this paper, a three-dimensional (3D) elemental approach has been adopted to predict the stochastic tyre vibration and hence the interior and exterior noise due to this kind of excitation. The road excitation has been modelled from the spectral density of a common road profile, supposing the road to be an isotropic surface. A linear Winkler bedding connects the 3D model of the tyre with the ground. The exterior noise has been evaluated by an elemental calculation of the radiation matrix of the tyre deformed by the static load on a concrete road. The noise inside the vehicle has also been calculated, using the transfer functions from the force transmitted to the hub and the noise inside the vehicle, which have been computed by a FEM model of a common car body. The simple formulation allows much quicker calculation than traditional nonlinear approaches, and appears to give results consistent with available measurements, although the effects of tyre rotation and of the nonlinearities in the contact model are yet to be quantified, and the method requires further experimental validation before practical application.

  19. An fMRI Study of Parietal Cortex Involvement in the Visual Guidance of Locomotion

    ERIC Educational Resources Information Center

    Billington, Jac; Field, David T.; Wilkie, Richard M.; Wann, John P.

    2010-01-01

    Locomoting through the environment typically involves anticipating impending changes in heading trajectory in addition to maintaining the current direction of travel. We explored the neural systems involved in the "far road" and "near road" mechanisms proposed by Land and Horwood (1995) using simulated forward or backward travel where participants…

  20. EVOLUTION OF PARTICLE NUMBER DISTRIBUTION NEAR ROADWAYS. PART II: THE ROAD-TO-AMBIENT PROCESS (R827352C011)

    EPA Science Inventory

    The 'road-to-ambient' evolution of particle number distributions near the 405 and 710 freeways in Los Angeles, California, in both summer and winter, were analyzed and then simulated by a multi-component sectional aerosol dynamic model. Condensation/evaporation and dilution we...

  1. Automatic 3D high-fidelity traffic interchange modeling using 2D road GIS data

    NASA Astrophysics Data System (ADS)

    Wang, Jie; Shen, Yuzhong

    2011-03-01

    3D road models are widely used in many computer applications such as racing games and driving simulations. However, almost all high-fidelity 3D road models were generated manually by professional artists at the expense of intensive labor. There are very few existing methods for automatically generating 3D high-fidelity road networks, especially for those existing in the real world. Real road network contains various elements such as road segments, road intersections and traffic interchanges. Among them, traffic interchanges present the most challenges to model due to their complexity and the lack of height information (vertical position) of traffic interchanges in existing road GIS data. This paper proposes a novel approach that can automatically produce 3D high-fidelity road network models, including traffic interchange models, from real 2D road GIS data that mainly contain road centerline information. The proposed method consists of several steps. The raw road GIS data are first preprocessed to extract road network topology, merge redundant links, and classify road types. Then overlapped points in the interchanges are detected and their elevations are determined based on a set of level estimation rules. Parametric representations of the road centerlines are then generated through link segmentation and fitting, and they have the advantages of arbitrary levels of detail with reduced memory usage. Finally a set of civil engineering rules for road design (e.g., cross slope, superelevation) are selected and used to generate realistic road surfaces. In addition to traffic interchange modeling, the proposed method also applies to other more general road elements. Preliminary results show that the proposed method is highly effective and useful in many applications.

  2. Discrete tyre model application for evaluation of vehicle limit handling performance

    NASA Astrophysics Data System (ADS)

    Siramdasu, Y.; Taheri, S.

    2016-11-01

    The goal of this study is twofold, first, to understand the transient and nonlinear effects of anti-lock braking systems (ABS), road undulations and driving dynamics on lateral performance of tyre and second, to develop objective handling manoeuvres and respective metrics to characterise these effects on vehicle behaviour. For studying the transient and nonlinear handling performance of the vehicle, the variations of relaxation length of tyre and tyre inertial properties play significant roles [Pacejka HB. Tire and vehicle dynamics. 3rd ed. Butterworth-Heinemann; 2012]. To accurately simulate these nonlinear effects during high-frequency vehicle dynamic manoeuvres, requires a high-frequency dynamic tyre model (? Hz). A 6 DOF dynamic tyre model integrated with enveloping model is developed and validated using fixed axle high-speed oblique cleat experimental data. Commercially available vehicle dynamics software CarSim® is used for vehicle simulation. The vehicle model was validated by comparing simulation results with experimental sinusoidal steering tests. The validated tyre model is then integrated with vehicle model and a commercial grade rule-based ABS model to perform various objective simulations. Two test scenarios of ABS braking in turn on a smooth road and accelerating in a turn on uneven and smooth roads are considered. Both test cases reiterated that while the tyre is operating in the nonlinear region of slip or slip angle, any road disturbance or high-frequency brake torque input variations can excite the inertial belt vibrations of the tyre. It is shown that these inertial vibrations can directly affect the developed performance metrics and potentially degrade the handling performance of the vehicle.

  3. Dredging in Sediments Containing Munitions and Explosives of Concern (MEC)

    DTIC Science & Technology

    2008-08-01

    bucket jaws are closed in order to “grab” a load of sediment. The loaded bucket is hoisted to the surface and side dumped into a trans- portation...digitally entering a percentage of total power (0 to 100 percent). The dredge’s hydraulic functions for the pump and hoist were controlled by solenoids...Cheryl Pollock Coastal and Hydraulics Laboratory U.S. Army Engineer Research and Development Center 3909 Halls Ferry Road Vicksburg, MS 39180-6199

  4. Estimation of the emission factors of PAHs by traffic with the model of atmospheric dispersion and deposition from heavy traffic road.

    PubMed

    Ozaki, N; Tokumitsu, H; Kojima, K; Kindaichi, T

    2007-01-01

    In order to consider the total atmospheric loadings of the PAHs (polycyclic aromatic hydrocarbons) from traffic activities, the emission factors of PAHs were estimated and from the obtained emission factors and vehicle transportation statistics, total atmospheric loadings were integrated and the loadings into the water body were estimated on a regional scale. The atmospheric concentration of PAHs was measured at the roadside of a road with heavy traffic in the Hiroshima area in Japan. The samplings were conducted in summer and winter. Atmospheric particulate matters (fine particle, 0.6-7 microm; coarse particle, over 7 microm) and their PAH concentration were measured. Also, four major emission sources (gasoline and diesel vehicle emissions, tire and asphalt debris) were assumed for vehicle transportation activities, the chemical mass balance method was applied and the source partitioning at the roadside was estimated. Furthermore, the dispersion of atmospheric particles from the vehicles was modelled and the emission factors of the sources were determined by the comparison to the chemical mass balance results. Based on emission factors derived from the modelling, an atmospheric dispersion model of nationwide scale (National Institute of Advanced Industrial Science and Technology - Atmospheric Dispersion Model for Exposure and Risk assessment) was applied, and the atmospheric concentration and loading to the ground were calculated for the Hiroshima Bay watershed area.

  5. Cognitive load, emotion, and performance in high-fidelity simulation among beginning nursing students: a pilot study.

    PubMed

    Schlairet, Maura C; Schlairet, Timothy James; Sauls, Denise H; Bellflowers, Lois

    2015-03-01

    Establishing the impact of the high-fidelity simulation environment on student performance, as well as identifying factors that could predict learning, would refine simulation outcome expectations among educators. The purpose of this quasi-experimental pilot study was to explore the impact of simulation on emotion and cognitive load among beginning nursing students. Forty baccalaureate nursing students participated in teaching simulations, rated their emotional state and cognitive load, and completed evaluation simulations. Two principal components of emotion were identified representing the pleasant activation and pleasant deactivation components of affect. Mean rating of cognitive load following simulation was high. Linear regression identiffed slight but statistically nonsignificant positive associations between principal components of emotion and cognitive load. Logistic regression identified a negative but statistically nonsignificant effect of cognitive load on assessment performance. Among lower ability students, a more pronounced effect of cognitive load on assessment performance was observed; this also was statistically non-significant. Copyright 2015, SLACK Incorporated.

  6. Evaluation of a two-dimensional numerical model for air quality simulation in a street canyon

    NASA Astrophysics Data System (ADS)

    Okamoto, Shin `Ichi; Lin, Fu Chi; Yamada, Hiroaki; Shiozawa, Kiyoshige

    For many urban areas, the most severe air pollution caused by automobile emissions appears along a road surrounded by tall buildings: the so=called street canyon. A practical two-dimensional numerical model has been developed to be applied to this kind of road structure. This model contains two submodels: a wind-field model and a diffusion model based on a Monte Carlo particle scheme. In order to evaluate the predictive performance of this model, an air quality simulation was carried out at three trunk roads in the Tokyo metropolitan area: Nishi-Shimbashi, Aoyama and Kanda-Nishikicho (using SF 6 as a tracer and NO x measurement). Since this model has two-dimensional properties and cannot be used for the parallel wind condition, the perpendicular wind condition was selected for the simulation. The correlation coefficients for the SF 6 and NO x data in Aoyama were 0.67 and 0.62, respectively. When predictive performance of this model is compared with other models, this model is comparable to the SRI model, and superior to the APPS three-dimensional numerical model.

  7. Assessment of rockfall hazard at Al-Noor Mountain, Makkah city (Saudi Arabia) using spatio-temporal remote sensing data and field investigation

    NASA Astrophysics Data System (ADS)

    Youssef, Ahmed M.; Pradhan, Biswajeet; Al-Kathery, Mohamed; Bathrellos, George D.; Skilodimou, Hariklia D.

    2015-01-01

    Rockfall is one of the major concerns along different urban areas and highways all over the world. Al-Noor Mountain is one of the areas that threaten rockfalls to the Al-Noor escarpment track road and the surrounding urban areas. Thousands of visitors and tourisms use the escarpment track road to visit Hira cave which is located at the top of Al-Noor Mountain. In addition, the surrounding urban areas of Al-Noor Mountain are continuously spreading over the recent years. The escarpment track road and the surrounding urban areas are highly vulnerable and suffers from recurrent rockfall mostly in the rainy season. The steep and highly jointed slope along the different faces of the mountain makes these zones prone to failure due to different actions such as weathering, erosion and anthropogenic effect. Therefore, an attempt has been made in this study to determine the Al-Noor cliff stability, by identifying the unstable areas, and to apply the rockfall simulations. A combination of remote sensing, field study and 2D computer simulation rockfall program were performed to assess surface characteristics of the cliff faces. Bounce height, total and translational kinetic energy, translational velocity, and number of blocks have been estimated. Different unstable zones along the Al-Noor Mountain and escarpment track road were determined using filed investigation and remote sensing based image analysis. In addition the rockfall simulation analysis indicated that rockfall in zone 1 and zone 2 of the Al-Noor Mountain may reach the urban areas, whereas rockfall in zone 3 will not reach the urban areas, and rockfalls along the Al-Noor escarpment track road will have highly impact on the tourists. Proper preventive measures are also suggested to arrest the movement of falling rocks before reaching the urban areas and the Al-Noor escarpment track road. If proper care is taken, then further uncertain rockfall hazards can be prevented.

  8. Crank inertial load has little effect on steady-state pedaling coordination.

    PubMed

    Fregly, B J; Zajac, F E; Dairaghi, C A

    1996-12-01

    Inertial load can affect the control of a dynamic system whenever parts of the system are accelerated or decelerated. During steady-state pedaling, because within-cycle variations in crank angular acceleration still exist, the amount of crank inertia present (which varies widely with road-riding gear ratio) may affect the within-cycle coordination of muscles. However, the effect of inertial load on steady-state pedaling coordination is almost always assumed to be negligible, since the net mechanical energy per cycle developed by muscles only depends on the constant cadence and workload. This study test the hypothesis that under steady-state conditions, the net joint torques produced by muscles at the hip, knee, and ankle are unaffected by crank inertial load. To perform the investigation, we constructed a pedaling apparatus which could emulate the low inertial load of a standard ergometer or the high inertial load of a road bicycle in high gear. Crank angle and bilateral pedal force and angle data were collected from ten subjects instructed to pedal steadily (i.e., constant speed across cycles) and smoothly (i.e., constant speed within a cycle) against both inertias at a constant workload. Virtually no statistically significant changes were found in the net hip and knee muscle joint torques calculated from an inverse dynamics analysis. Though the net ankle muscle joint torque, as well as the one- and two-legged crank torque, showed statistically significant increases at the higher inertia, the changes were small. In contrast, large statistically significant reductions were found in crank kinematic variability both within a cycle and between cycles (i.e., cadence), primarily because a larger inertial load means a slower crank dynamic response. Nonetheless, the reduction in cadence variability was somewhat attenuated by a large statistically significant increase in one-legged crank torque variability. We suggest, therefore, that muscle coordination during steady-state pedaling is largely unaffected, though less well regulated, when crank inertial load is increased.

  9. Water resources of Monroe County, New York, water years 1997-99, with emphasis on water quality in the Irondequoit Creek basin—Atmospheric deposition, ground water, streamflow, trends in water quality, and chemical loads to Irondequoit Bay

    USGS Publications Warehouse

    Sherwood, Donald A.

    2003-01-01

    Irondequoit Creek drains 169 square miles in the eastern part of Monroe County. Over time, nutrients transported by Irondequoit Creek to Irondequoit Bay on Lake Ontario have contributed to the eutrophication of the bay. Sewage-treatment-plant effluent, a major source of nutrients to the creek and its tributaries, was eliminated from the basin in 1979 by diversion to a regional wastewater-treatment facility, but sediment and contaminants from nonpoint sources continue to enter the creek and Irondequoit Bay.This report, the fourth in a series of reports that present interpretive analyses of the hydrologic data collected in Monroe County since 1984, interprets data from four surface-water monitoring sites in the Irondequoit Creek basin—Irondequoit Creek at Railroad Mills, East Branch Allen Creek at Pittsford, Allen Creek near Rochester, and Irondequoit Creek at Blossom Road. It also interprets data from three sites in the the Genesee River basin—Oatka Creek at Garbutt, Honeoye Creek at Honeoye Falls, and Black Creek at Churchville—as well as the Genesee River at Charlotte Pump Station, and also from a site on Northrup Creek at North Greece. The Northrup Creek site drains a 23.5-square-mile basin in western Monroe County, and provides information on surface-water quality in streams west of the Genesee River and on loads of nutrients delivered to Long Pond, a small eutrophic embayment of Lake Ontario. The report also includes water-level and water-quality data from nine observation wells in Ellison Park, and atmospheric-deposition data from a collection site at Mendon Ponds County Park.Average annual loads of some chemical constituents in atmospheric deposition for 1997–99 differed considerably from those for the long-term period 1984–96. Ammonia and potassium loads for 1997-99 were 144 and 118 percent greater, respectively, than for the previous period. Sodium and ammonia + organic nitrogen loads were 87 and 60 percent greater, respectively. Average annual loads of sulfate and orthophosphate for 1997-99 were 36 and 30 percent lower, respectively, than for the previous period.Loads of all nutrients deposited on the Irondequoit basin from atmospheric sources during 1997–99 greatly exceeded those transported by Irondequoit Creek. The ammonia load deposited on the basin was 139 times the load transported at Blossom Road (the most downstream site); the ammonia + organic nitrogen load was 6.3 times greater, orthophosphate 7.5 times greater, total phosphorus 1.3 times greater and nitrite + nitrate 1.5 times greater. Average yields of dissolved chloride and dissolved sulfate from atmospheric sources were much smaller than those transported by streamflow at Blossom Road.chloride was about 2 percent and sulfate about 8 percent of the amount transported.Trends in concentration of chemical constituents in surface water generally can be attributed to changes in land use, annual and seasonal variations in streamflow, and annual variations in the application of road salt to county highways and roads.Concentrations of several constituents in streams of the Irondequoit Creek basin showed statistically significant (α=0.05) trends from the beginning of their period of record through 1999. The constituent with the greatest number of significant trends was ammonia + organic nitrogen, with downward trends ranging from 4.1 to 5.6 percent per year at Allen Creek, Irondequoit Creek at Blossom Road, and East Branch Allen Creek. Orthophosphate showed an upward trend of 4.1 percent per year at Irondequoit Creek at Railroad Mills (the most upstream site). Dissolved chloride showed upward trends at Railroad Mills, Allen Creek, and Blossom Road. No trends in volatile suspended solids were noted at any of the four Irondequoit basin sites.Northrup Creek showed significant downward trends in concentrations of ammonia + organic nitrogen (3.3 percent per year), total phosphorus (3.4 percent per year), and orthophosphate (5.5 percent per year), and an upward trend for dissolved sulfate (1.8 percent per year). The Genesee River at Charlotte Pump Station showed downward trends of 6.1 percent per year for ammonia + organic nitrogen and 0.1 percent per year for chloride, and upward trends of 1.7 percent per year for total phosphorus and 6.6 percent per year for orthophosphate.Mean annual yields (mass per unit area) of most constituents at the Irondequoit Creek basin sites were similar to those noted for the previous report period (1994–96). East Branch Allen Creek showed lower yields of all constituents during 1997–99 than previously, even though runoff during 1997–99 was greater. These lower yields are attributed to the construction of an upstream detention basin on East Branch Allen Creek in 1995.Statistical analysis of long-term (greater than 12 years) streamflow records for unregulated streams in Monroe County indicated that annual mean flows for water years 1997–99 were in the normal range (75th to 25th percentile), although Allen Creek continues to show a significant downward trend in mean monthly streamflow during the 1984–99 water years.

  10. Summit Station Skiway Cost Analysis

    DTIC Science & Technology

    2016-07-01

    Laboratory (CRREL) U.S. Army Engineer Research and Development Center (ERDC) 72 Lyme Road Hanover, NH 03755-1290 Final Report Approved for...cargo loads. To explore further skiway improvement and cost saving techniques, this report reviews alternative maintenance and construction options...3 2.2 Maintenance

  11. 36 CFR 7.43 - Natchez Trace Parkway.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... vehicles. Animal-drawn vehicles or implements are prohibited on the main parkway road. (3) Farm vehicles. Farm vehicles, including agricultural implements, with or without load carrying capacity, and whether... from the Superintendent or his representative. School buses may travel on the parkway without such...

  12. 36 CFR 7.43 - Natchez Trace Parkway.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... vehicles. Animal-drawn vehicles or implements are prohibited on the main parkway road. (3) Farm vehicles. Farm vehicles, including agricultural implements, with or without load carrying capacity, and whether... from the Superintendent or his representative. School buses may travel on the parkway without such...

  13. 36 CFR 7.43 - Natchez Trace Parkway.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... vehicles. Animal-drawn vehicles or implements are prohibited on the main parkway road. (3) Farm vehicles. Farm vehicles, including agricultural implements, with or without load carrying capacity, and whether... from the Superintendent or his representative. School buses may travel on the parkway without such...

  14. 36 CFR 7.43 - Natchez Trace Parkway.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... vehicles. Animal-drawn vehicles or implements are prohibited on the main parkway road. (3) Farm vehicles. Farm vehicles, including agricultural implements, with or without load carrying capacity, and whether... from the Superintendent or his representative. School buses may travel on the parkway without such...

  15. Mechanical Network in Titin Immunoglobulin from Force Distribution Analysis

    PubMed Central

    Wilmanns, Matthias; Gräter, Frauke

    2009-01-01

    The role of mechanical force in cellular processes is increasingly revealed by single molecule experiments and simulations of force-induced transitions in proteins. How the applied force propagates within proteins determines their mechanical behavior yet remains largely unknown. We present a new method based on molecular dynamics simulations to disclose the distribution of strain in protein structures, here for the newly determined high-resolution crystal structure of I27, a titin immunoglobulin (IG) domain. We obtain a sparse, spatially connected, and highly anisotropic mechanical network. This allows us to detect load-bearing motifs composed of interstrand hydrogen bonds and hydrophobic core interactions, including parts distal to the site to which force was applied. The role of the force distribution pattern for mechanical stability is tested by in silico unfolding of I27 mutants. We then compare the observed force pattern to the sparse network of coevolved residues found in this family. We find a remarkable overlap, suggesting the force distribution to reflect constraints for the evolutionary design of mechanical resistance in the IG family. The force distribution analysis provides a molecular interpretation of coevolution and opens the road to the study of the mechanism of signal propagation in proteins in general. PMID:19282960

  16. Investigation of the effects of slow-release fertilizer and struvite in biodegradation in filter drains and potential application of treated water in irrigation of road verges.

    PubMed

    Theophilus, Stephen C; Mbanaso, Fredrick U; Nnadi, Ernest O; Onyedeke, Kingsley T

    2017-11-14

    Filter drains are usually laid along the margins of highways. Highway runoffs are polluted with hydrocarbons and high levels of total dissolved solids. Therefore, effective pollution removal mechanism is necessary in order to avoid contamination of surrounding soils and groundwater. Biodegradation is amongst pollution removal mechanisms in filter drains, but it is a relatively slow process which is dependent on wide range of factors including the type of pollutant and availability of nutrients. This paper reports on a study conducted to investigate the impact of slow-release fertilizer and struvite in enhancement of biodegradation of hydrocarbon in filter drains. Filter drain models incorporated with geotextile were challenged with cumulative oil loading of 178 mg/m 2 /week with a view to comparing the efficiency of these two nutrient sources under high oil pollution loading and realistic rainfall conditions of 13 mm/week. Nutrients and street dust were applied at one-off rate of 17 g/m 2 and 1.55 g/rig to provide nutrient enhancement and simulate field conditions respectively. The impact of the nutrients was studied by monitoring bacterial and fungal growth using nutrient agar, Rose Bengal Agar media and CO2 evolution. EC, pH, heavy metals, TPH, elemental analysis and SAR were used to investigate water quality of effluent of filter drains for potential application as irrigation fluid for trees and flowers planted on road verges. The results show that nutrient application encouraged microbial activities and enhanced biodegradation rates with differences in type of nutrient applied. Also, it was observed that incorporation of geotextiles in filter drains improved pollution retention efficiency and there is a potential opportunity for utilization of struvite in SuDS systems as sustainable nutrient source.

  17. [Nitrogen and phosphorus composition in urban runoff from the new development area in Beijing].

    PubMed

    Li, Li-Qing; Lü, Shu-Cong; Zhu, Ren-Xiao; Liu, Ze-Quan; Shan, Bao-Qing

    2012-11-01

    Stormwater runoff samples were collected from two impervious roof and road of the new development area in Beijing, during three rainfall events in an attempt to characterize the urban runoff and determine nitrogen and phosphorus composition. The outcomes are expected to offer the practical guidance in sources control of urban runoff pollution. The results indicated that the stormwater runoff from the studied area presented a strong first flush for all monitored events and constituents. Eighty percent of the total pollutant loads were transported by the first 10 mm flow volume for roof runoff, whereas 80% of the total pollutant loads were discharged by the first 15 mm flow volume for road runoff. Average EMCs of TSS, COD, TN, NH4(+) -N, NO3(-) -N and TP for roof runoff were 50.2 mg x L(-1), 81.7 mg x L(-1), 6.07 mg x L(-1), 2.94 mg x L(-1), 1.05 mg x L(-1), and 0.11 mg x L(-1), respectively. Average EMCs of TSS, COD, TN, NH4(+) -N, NO3(-)-N and TP for road runoff were 539.0 mg x L(-1), 276.4 mg x L(-1), 7.00 mg x L(-1), 1.71 mg x L(-1), 1.51 mg x L(-1), and 0.61 mg x L(-1), respectively. Moreover, for the roof runoff, the particle-bound fraction was 20.8% for COD, 12.3% for TN, and 49.7% for TP. For road runoff, the particle-bound fraction was 68.6% for COD, 20.0% for TN, and 73.6% for TP. Nitrogen in roof runoff was predominantly dissolved (87.7%), with ammonia (57.6%) and nitrate (22.5%). Nitrogen in road runoff was also predominantly dissolved (80.0%), with ammonia (42.1%) and nitrate (35.0%). These findings can assist the development of effective source control strategies to immobilize dissolved and particulate-bound nitrogen/phosphorus in urban stormwater.

  18. Performance evaluation of a cable bolted yield-abutment gate road system at the Crandall Canyon No. 1 Mine, Genwal Resources, Inc., Huntington, Utah

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Koehler, J.R.; DeMarco, M.J.; Marshall, R.J.

    1996-12-01

    Although two-entry yield pillar-based gate roads supported by wooden cribs have been commonly used throughout longwalling in the Wasatch Plateau/Roan Cliffs coalfield of central Utah, a three-entry yield-abutment gate road configuration was recently trialed in the Hiawatha Seam at the Genwal Resources (GRI) Crandall Canyon No. 1 Mine, near Huntington, UT. Pillar, entry, and cable bolt performance were monitored through second panel mining using a fairly extensive array of geomechanical instruments installed over a span of four crosscuts. Ground pressure and entry closure measurements confirmed that the 9.1-m-wide (30-ft) yield pillar was partially shielded from first panel longwall loads bymore » the 36.6-m-wide (120-ft) abutment pillar, and consequently, experienced only minor yielding until the approach of the second panel face. Complete yielding of the 9.1-m-wide (30-ft) pillar occurred when the second panel was approximately 6.1 m (20 ft) in by the instrumentation site. Average cable bolt loads and differential roof sag remained low through second panel mining and tailgate entry ground conditions were excellent; however, very high ground pressures in the abutment and yield pillars, and second panel rib strongly suggest a high potential for coal bumps utilizing this gate road configuration at mining cover depths in excess of 396 to 457 m (1300 to 1500 ft). This conclusion is supported by the suspected occurrence of small coal bumps along the abutment pillar ribs, observed indirectly as fresh debris in the middle entry just behind the second face. This paper presents a case history developed from the geotechnical measurements and on-site observations of this unique application of a yield-abutment gate road configuration and cable support system in the Hiawatha Seam.« less

  19. Climatic Characteristics of Slovakia in the Years 1971 to 2011 from the Aspect of Pavement Design

    NASA Astrophysics Data System (ADS)

    Decky, Martin; Remisova, Eva; Kovalcik, Lubomír; Dibdiakova, Jana; Hajek, Matej

    2017-12-01

    Contribution follows the previous work of authors in the field of implementation of objectified results of climate change in the design of roads, especially their pavement [1] to [3]. Climate conditions are besides traffic load, one of the permanent external factors adversely affecting the physical and mechanical properties of the construction layers. For designing concrete pavements is used in SR conditions average annual air temperature Tm and frost index for design of asphalt and concrete pavements. As part of the research activities carried out at the workplace, the authors statistically evaluated average daily temperatures of SR meteorological stations covering most of the SR territory with altitude from 115 to 695 m above sea level in the years 1971 to 2011. Act No. 135/1961 Coll. (Road Act) states that the design of road pavements is performed according to valid Slovak technical standards, technical regulations and objectively identified results of research and development for road infrastructure. On the basis of the presented correlations, it can be stated that the presented research results can be used immediately for SR conditions in the design of road pavements.

  20. A queuing model for road traffic simulation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Guerrouahane, N.; Aissani, D.; Bouallouche-Medjkoune, L.

    We present in this article a stochastic queuing model for the raod traffic. The model is based on the M/G/c/c state dependent queuing model, and is inspired from the deterministic Godunov scheme for the road traffic simulation. We first propose a variant of M/G/c/c state dependent model that works with density-flow fundamental diagrams rather than density-speed relationships. We then extend this model in order to consider upstream traffic demand as well as downstream traffic supply. Finally, we show how to model a whole raod by concatenating raod sections as in the deterministic Godunov scheme.

  1. Are driving and overtaking on right curves more dangerous than on left curves?

    PubMed

    Othman, Sarbaz; Thomson, Robert; Lannér, Gunnar

    2010-01-01

    It is well known that crashes on horizontal curves are a cause for concern in all countries due to the frequency and severity of crashes at curves compared to road tangents. A recent study of crashes in western Sweden reported a higher rate of crashes in right curves than left curves. To further understand this result, this paper reports the results of novel analyses of the responses of vehicles and drivers during negotiating and overtaking maneuvers on curves for right hand traffic. The overall objectives of the study were to find road parameters for curves that affect vehicle dynamic responses, to analyze these responses during overtaking maneuvers on curves, and to link the results with driver behavior for different curve directions. The studied road features were speed, super-elevation, radius and friction including their interactions, while the analyzed vehicle dynamic factors were lateral acceleration and yaw angular velocity. A simulation program, PC-Crash, has been used to simulate road parameters and vehicle response interaction in curves. Overtaking maneuvers have been simulated for all road feature combinations in a total of 108 runs. Analysis of variances (ANOVA) was performed, using two sided randomized block design, to find differences in vehicle responses for the curve parameters. To study driver response, a field test using an instrumented vehicle and 32 participants was reviewed as it contained longitudinal speed and acceleration data for analysis. The simulation results showed that road features affect overtaking performance in right and left curves differently. Overtaking on right curves was sensitive to radius and the interaction of radius with road condition; while overtaking on left curves was more sensitive to super-elevation. Comparisons of lateral acceleration and yaw angular velocity during these maneuvers showed different vehicle response configurations depending on curve direction and maneuver path. The field test experiments also showed that drivers behave differently depending on the curve direction where both speed and acceleration were higher on right than left curves. The implication of this study is that curve direction should be taken into consideration to a greater extent when designing and redesigning curves. It appears that the driver and the vehicle are influenced by different infrastructure factors depending on the curve direction. In addition, the results suggest that the vehicle dynamics response alone cannot explain the higher crash risk in right curves. Further studies of the links between driver, vehicle, and highway characteristics are needed, such as naturalistic driving studies, to identify the key safety indicators for highway safety.

  2. A Tool for Modelling the Probability of Landslides Impacting Road Networks

    NASA Astrophysics Data System (ADS)

    Taylor, Faith E.; Santangelo, Michele; Marchesini, Ivan; Malamud, Bruce D.; Guzzetti, Fausto

    2014-05-01

    Triggers such as earthquakes or heavy rainfall can result in hundreds to thousands of landslides occurring across a region within a short space of time. These landslides can in turn result in blockages across the road network, impacting how people move about a region. Here, we show the development and application of a semi-stochastic model to simulate how landslides intersect with road networks during a triggered landslide event. This was performed by creating 'synthetic' triggered landslide inventory maps and overlaying these with a road network map to identify where road blockages occur. Our landslide-road model has been applied to two regions: (i) the Collazzone basin (79 km2) in Central Italy where 422 landslides were triggered by rapid snowmelt in January 1997, (ii) the Oat Mountain quadrangle (155 km2) in California, USA, where 1,350 landslides were triggered by the Northridge Earthquake (M = 6.7) in January 1994. For both regions, detailed landslide inventory maps for the triggered events were available, in addition to maps of landslide susceptibility and road networks of primary, secondary and tertiary roads. To create 'synthetic' landslide inventory maps, landslide areas (AL) were randomly selected from a three-parameter inverse gamma probability density function, consisting of a power law decay of about -2.4 for medium and large values of AL and an exponential rollover for small values of AL. The number of landslide areas selected was based on the observed density of landslides (number of landslides km-2) in the triggered event inventories. Landslide shapes were approximated as ellipses, where the ratio of the major and minor axes varies with AL. Landslides were then dropped over the region semi-stochastically, conditioned by a landslide susceptibility map, resulting in a synthetic landslide inventory map. The originally available landslide susceptibility maps did not take into account susceptibility changes in the immediate vicinity of roads, therefore our landslide susceptibility map was adjusted to further reduce the susceptibility near each road based on the road level (primary, secondary, tertiary). For each model run, we superimposed the spatial location of landslide drops with the road network, and recorded the number, size and location of road blockages recorded, along with landslides within 50 and 100 m of the different road levels. Network analysis tools available in GRASS GIS were also applied to measure the impact upon the road network in terms of connectivity. The model was performed 100 times in a Monte-Carlo simulation for each region. Initial results show reasonable agreement between model output and the observed landslide inventories in terms of the number of road blockages. In Collazzone (length of road network = 153 km, landslide density = 5.2 landslides km-2), the median number of modelled road blockages over 100 model runs was 5 (±2.5 standard deviation) compared to the mapped inventory observed number of 5 road blockages. In Northridge (length of road network = 780 km, landslide density = 8.7 landslides km-2), the median number of modelled road blockages over 100 model runs was 108 (±17.2 standard deviation) compared to the mapped inventory observed number of 48 road blockages. As we progress with model development, we believe this semi-stochastic modelling approach will potentially aid civil protection agencies to explore different scenarios of road network potential damage as the result of different magnitude landslide triggering event scenarios.

  3. Comparison of on-road emissions for hybrid and regular transit buses.

    PubMed

    Hallmark, Shauna L; Wang, Bo; Sperry, Robert

    2013-10-01

    Hybrid technology offers an attractive option for transit buses, since it has the potential to significantly reduce operating costs for transit agencies. The main impetus behind use of hybrid transit vehicles is fuel savings and reduced emissions. Laboratory tests have indicated that hybrid transit buses can have significantly lower emissions compared with conventional transit buses. However the number of studies is limited and laboratory tests may not represent actual driving conditions, since in-use vehicle operation differs from laboratory test cycles. This paper describes an on-road evaluation of in-use emission differences between hybrid-electric and conventional transit buses for the Ames, Iowa transit authority, CyRide. Emissions were collected on-road using a portable emissions monitoring system (PEMS) for three hybrid and two control buses. Emissions were collected for at least one operating bus day. Each bus was evaluated over the same route pattern, which utilizes the same driver. The number of passengers embarking or disembarking at each stop was collected by an on-board data collector so that passenger load could be included. Vehicle emissions are correlated to engine load demand, which is a function of factors such as vehicle load, speed, and acceleration. PEMS data are provided second by second and vehicle-specific power (VSP) was calculated for each row of data. Instantaneous data were stratified into the defined VSP bins and then average modal emission rates and standard errors were calculated for each bus for each pollutant. Pollutants were then compared by bus type. Carbon dioxide, carbon monoxide, and hydrocarbon emissions were higher for the regular buses across most VSP bins than for the hybrid buses. Nitrogen oxide emissions were unexpectedly higher for the hybrid buses than for the control buses.

  4. Effects of Road Density and Road-Salt Application Practices on Sodium and Chloride Loads to the Scituate Reservoir, Rhode Island

    NASA Astrophysics Data System (ADS)

    Waldron, M. C.; Nimiroski, M.

    2001-05-01

    The Scituate Reservoir drainage basin is the drinking-water source area for two thirds of the population of Rhode Island. The effects of road density and road-salt-application practices on sodium and chloride concentrations in streams in the drainage basin were examined using concentration data collected at intervals of one to six months from January 1982 through June 2000 at 32 stream sites distributed throughout the basin. Median concentrations of sodium and chloride for individual streams during the period of data collection were related to 1995 road densities (road miles per square mile of subbasin) for roads maintained by the Rhode Island Department of Transportation (State-maintained roads) and for roads maintained by the four municipalities in the drainage basin (locally maintained roads). Nearly 60 percent of the variation in median stream sodium and chloride concentrations was accounted for by the variation in density of State-maintained roads (R2= 0.595, p < 0.0001). In contrast, no correlations could be identified between median concentrations of sodium and chloride in streams and the densities of locally maintained roads in the subbasins (R2 = 0.001, p = 0.8771). Also, there was no difference in the relations between median stream sodium concentrations and subbasin road densities for data collected before and after a 1990 State-mandated reduction in the rate of application of sodium during winter deicing of State-maintained roads. Analysis of data on sources of sodium and chloride in the Scituate Reservoir drainage basin during water year 2000 (October 1999 through September 2000) indicates that, while the lengths and densities of locally maintained roads were greater than those of State-maintained roads in most subbasins, the total amount of sodium applied during water year 2000 was nearly three times greater for State-maintained roads than for locally maintained roads. This would be expected, given that State-maintained roads carry more traffic at higher speeds than do locally maintained roads. In addition, the State-maintained roads tend to have more efficient drainage systems that quickly transport runoff directly to the streams. The lack of effect of the reduced sodium application rate on the relation between median stream sodium concentration and density of State-maintained roads may be due to inaccurate monitoring of application rates or to mobilization of sodium previously applied and stored in drainage basin soils. Thus, the amounts of sodium and chloride transported by tributary streams to the Scituate Reservoir depend more on the type of roads and other conditions in the tributary subbasins than on the actual length or density of the roads.

  5. The composite load spectra project

    NASA Technical Reports Server (NTRS)

    Newell, J. F.; Ho, H.; Kurth, R. E.

    1990-01-01

    Probabilistic methods and generic load models capable of simulating the load spectra that are induced in space propulsion system components are being developed. Four engine component types (the transfer ducts, the turbine blades, the liquid oxygen posts and the turbopump oxidizer discharge duct) were selected as representative hardware examples. The composite load spectra that simulate the probabilistic loads for these components are typically used as the input loads for a probabilistic structural analysis. The knowledge-based system approach used for the composite load spectra project provides an ideal environment for incremental development. The intelligent database paradigm employed in developing the expert system provides a smooth coupling between the numerical processing and the symbolic (information) processing. Large volumes of engine load information and engineering data are stored in database format and managed by a database management system. Numerical procedures for probabilistic load simulation and database management functions are controlled by rule modules. Rules were hard-wired as decision trees into rule modules to perform process control tasks. There are modules to retrieve load information and models. There are modules to select loads and models to carry out quick load calculations or make an input file for full duty-cycle time dependent load simulation. The composite load spectra load expert system implemented today is capable of performing intelligent rocket engine load spectra simulation. Further development of the expert system will provide tutorial capability for users to learn from it.

  6. Using rainfall simulators to test wood shreddings for erosion control

    Treesearch

    James Gronier; Randy Foltz; Charlie Showers

    2005-01-01

    The U.S. Department of Agriculture Forest Service is considering alternative methods of erosion control when constructing roads, decommissioning roads, protecting lands burned by wildland fires, and reclaiming lands disturbed by other activities. This article is the second in a series of tech tips that discuss the use of wood shreddings for erosion control. The first...

  7. Mapping the optimal forest road network based on the multicriteria evaluation technique: the case study of Mediterranean Island of Thassos in Greece.

    PubMed

    Tampekis, Stergios; Sakellariou, Stavros; Samara, Fani; Sfougaris, Athanassios; Jaeger, Dirk; Christopoulou, Olga

    2015-11-01

    The sustainable management of forest resources can only be achieved through a well-organized road network designed with the optimal spatial planning and the minimum environmental impacts. This paper describes the spatial layout mapping for the optimal forest road network and the environmental impacts evaluation that are caused to the natural environment based on the multicriteria evaluation (MCE) technique at the Mediterranean island of Thassos in Greece. Data analysis and its presentation are achieved through a spatial decision support system using the MCE method with the contribution of geographic information systems (GIS). With the use of the MCE technique, we evaluated the human impact intensity to the forest ecosystem as well as the ecosystem's absorption from the impacts that are caused from the forest roads' construction. For the human impact intensity evaluation, the criteria that were used are as follows: the forest's protection percentage, the forest road density, the applied skidding means (with either the use of tractors or the cable logging systems in timber skidding), the timber skidding direction, the visitors' number and truck load, the distance between forest roads and streams, the distance between forest roads and the forest boundaries, and the probability that the forest roads are located on sights with unstable soils. In addition, for the ecosystem's absorption evaluation, we used forestry, topographical, and social criteria. The recommended MCE technique which is described in this study provides a powerful, useful, and easy-to-use implement in order to combine the sustainable utilization of natural resources and the environmental protection in Mediterranean ecosystems.

  8. A robust nonlinear skid-steering control design applied to the MULE (6x6) unmanned ground vehicle

    NASA Astrophysics Data System (ADS)

    Kaloust, Joseph

    2006-05-01

    The paper presents a robust nonlinear skid-steering control design concept. The control concept is based on the recursive/backstepping control design technique and is capable of compensating for uncertainties associated with sensor noise measurements and/or system dynamic state uncertainties. The objective of this control design is to demonstrate the performance of the nonlinear controller under uncertainty associate with road traction (rough off-road and on-road terrain). The MULE vehicle is used in the simulation modeling and results.

  9. Online Optimal Control of Connected Vehicles for Efficient Traffic Flow at Merging Roads

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rios-Torres, Jackeline; Malikopoulos, Andreas; Pisu, Pierluigi

    2015-01-01

    This paper addresses the problem of coordinating online connected vehicles at merging roads to achieve a smooth traffic flow without stop-and-go driving. We present a framework and a closed-form solution that optimize the acceleration profile of each vehicle in terms of fuel economy while avoiding collision with other vehicles at the merging zone. The proposed solution is validated through simulation and it is shown that coordination of connected vehicles can reduce significantly fuel consumption and travel time at merging roads.

  10. Explicit and implicit processes in behavioural adaptation to road width.

    PubMed

    Lewis-Evans, Ben; Charlton, Samuel G

    2006-05-01

    The finding that drivers may react to safety interventions in a way that is contrary to what was intended is the phenomenon of behavioural adaptation. This phenomenon has been demonstrated across various safety interventions and has serious implications for road safety programs the world over. The present research used a driving simulator to assess behavioural adaptation in drivers' speed and lateral displacement in response to manipulations of road width. Of interest was whether behavioural adaptation would occur and whether we could determine whether it was the result of explicit, conscious decisions or implicit perceptual processes. The results supported an implicit, zero perceived risk model of behavioural adaptation with reduced speeds on a narrowed road accompanied by increased ratings of risk and a marked inability of the participants to identify that any change in road width had occurred.

  11. Towards high-performance materials for road construction

    NASA Astrophysics Data System (ADS)

    Gladkikh, V.; Korolev, E.; Smirnov, V.

    2017-10-01

    Due to constant increase of traffic, modern road construction is in need of high-performance pavement materials. The operational performance of such materials can be characterized by many properties. Nevertheless, the most important ones are resistance to rutting and resistance to dynamical loads. It was proposed earlier to use sulfur extended asphalt concrete in road construction practice. To reduce the emission of sulfur dioxide and hydrogen sulfide during the concrete mix preparation and pavement production stages, it is beneficial to make such a concrete on the base of complex sulfur modifier. In the present work the influence of the complex modifier to mechanical properties of sulfur extended asphalt concrete was examined. It was shown that sulfur extended asphalt concrete is of high mechanical properties. It was also revealed that there as an anomalous negative correlations between strain capacity, fatigue life and fracture toughness.

  12. Novel models and algorithms of load balancing for variable-structured collaborative simulation under HLA/RTI

    NASA Astrophysics Data System (ADS)

    Yue, Yingchao; Fan, Wenhui; Xiao, Tianyuan; Ma, Cheng

    2013-07-01

    High level architecture(HLA) is the open standard in the collaborative simulation field. Scholars have been paying close attention to theoretical research on and engineering applications of collaborative simulation based on HLA/RTI, which extends HLA in various aspects like functionality and efficiency. However, related study on the load balancing problem of HLA collaborative simulation is insufficient. Without load balancing, collaborative simulation under HLA/RTI may encounter performance reduction or even fatal errors. In this paper, load balancing is further divided into static problems and dynamic problems. A multi-objective model is established and the randomness of model parameters is taken into consideration for static load balancing, which makes the model more credible. The Monte Carlo based optimization algorithm(MCOA) is excogitated to gain static load balance. For dynamic load balancing, a new type of dynamic load balancing problem is put forward with regards to the variable-structured collaborative simulation under HLA/RTI. In order to minimize the influence against the running collaborative simulation, the ordinal optimization based algorithm(OOA) is devised to shorten the optimization time. Furthermore, the two algorithms are adopted in simulation experiments of different scenarios, which demonstrate their effectiveness and efficiency. An engineering experiment about collaborative simulation under HLA/RTI of high speed electricity multiple units(EMU) is also conducted to indentify credibility of the proposed models and supportive utility of MCOA and OOA to practical engineering systems. The proposed research ensures compatibility of traditional HLA, enhances the ability for assigning simulation loads onto computing units both statically and dynamically, improves the performance of collaborative simulation system and makes full use of the hardware resources.

  13. Road March Performance of Special Operations Soldiers Carrying Various Loads and Load Distributions

    DTIC Science & Technology

    1993-01-01

    groups were used (Ramos and Knaplk, 1979; Knapik et al,, 1980 ; Hermansen et al., 1972), In the hand-grip test, the 7 soldier, in a seated position...Inventory (DIshman et al,, 1980 ). The POMS was a 65-item questionnaire which provided measures of six mood states, Soldiers scored each item on a five-point...estimates require individual calibration (Acheson et al., 1980 ) and heart rate can be influenced by a number of factors including training state (Saltin

  14. 40. HISTORIC VIEW LOOKING WEST AT THE TEST STAND. NOTE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    40. HISTORIC VIEW LOOKING WEST AT THE TEST STAND. NOTE THE LOAD CELL APPARATUS LOCATED ABOVE THE ROCKET. THE SPACE BETWEEN THE BOTTOM OF THE LOAD CELL APPARATUS AND THE TOP OF THE ROCKET IS THE DIFFERENCE IN SIZE BETWEEN THE REDSTONE ROCKET AND ITS DECEDENT THE JUPITER C ROCKET. THE GAP IS FILLED WITH A SPACER WHEN THEY TEST A REDSTONE ROCKET. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

  15. Testing of Lightweight Fuel Cell Vehicles System at Low Speeds with Energy Efficiency Analysis

    NASA Astrophysics Data System (ADS)

    Mustaffa, Muhammad Rizuwan B.; Mohamed, Wan Ahmad Najmi B. Wan

    2013-12-01

    A fuel cell vehicle power train mini test bench was developed which consists of a 1 kW open cathode hydrogen fuel cell, electric motor, wheel, gearing system, DC/DC converter and vehicle control system (VCS). Energy efficiency identification and energy flow evaluation is a useful tool in identifying a detail performance of each component and sub-systems in a fuel cell vehicle system configuration. Three artificial traction loads was simulated at 30 kg, 40 kg and 50 kg force on a single wheel drive configuration. The wheel speed range reported here covers from idle to 16 km/h (low speed range) as a preliminary input in the research work frame. The test result shows that the system efficiency is 84.5 percent when the energy flow is considered from the fuel cell to the wheel and 279 watts of electrical power was produced by the fuel cell during that time. Dynamic system responses was also identified as the load increases beyond the motor traction capabilities where the losses at the converter and motor controller increased significantly as it tries to meet the motor traction power demands. This work is currently being further expanded within the work frame of developing a road-worthy fuel cell vehicle.

  16. Characterizing spatial variability of air pollution from vehicle traffic around the Houston Ship Channel area

    NASA Astrophysics Data System (ADS)

    Zhang, Xueying; Craft, Elena; Zhang, Kai

    2017-07-01

    Mobile emissions are a major source of urban air pollution and have been associated with a variety of adverse health outcomes. The Houston Ship Channel area is the home of a large number of diesel-powered vehicles emitting fine particulate matter (PM2.5; ≤2.5 μm in aerodynamic diameter) and nitrogen oxides (NOx). However, the spatial variability of traffic-related air pollutants in the Houston Ship Channel area has rarely been investigated. The objective of this study is to characterize spatial variability of PM2.5 and NOx concentrations attributable to on-road traffic in the Houston Ship Channel area in the year of 2011. We extracted the road network from the Texas Department of Transportation Road Inventory, and calculated emission rates using the Motor Vehicle Emission Simulator version 2014a (MOVES2014a). These parameters and preprocessed meteorological parameters were entered into a Research LINE-source Dispersion Model (RLINE) to conduct a simulation. Receptors were placed at 50 m resolution within 300 m to major roads and at 150 m resolution in the rest of the area. Our findings include that traffic-related PM2.5 were mainly emitted from trucks, while traffic-related NOx were emitted from both trucks and cars. The traffic contributed 0.90 μg/m3 PM2.5 and 29.23 μg/m3 NOx to the annual average mass concentrations of on-road air pollution, and the concentrations of the two pollutants decreased by nearly 40% within 500 m distance to major roads. The pollution level of traffic-related PM2.5 and NOx was higher in winter than those in the other three seasons. The Houston Ship Channel has earlier morning peak hours and relative late afternoon hours, which indicates the influence of goods movement from port activity. The varied near-road gradients illustrate that proximities to major roads are not an accurate surrogate of traffic-related air pollution.

  17. 49 CFR 525.7 - Basis for petition.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... efficient production mix of vehicle configurations and base levels of its passenger automobiles which the...) The petitioner's annual total production and production mix of passenger automobiles manufactured or... road load setting, determined in accordance with 40 CFR part 86, and the method used to determine that...

  18. Pavement damage due to different tire and loading configurations on secondary roads.

    DOT National Transportation Integrated Search

    2009-10-15

    Due to the large percentage of goods moved by commercial trucks and its ever-growing freight industry, the U.S. needs innovative technologies to improve the efficiency of trucking operations and ensure continuous growth of the economy. One example of...

  19. Over-the-road testing of the instrumented tank car : a load environment study.

    DOT National Transportation Integrated Search

    2010-05-01

    Fractures have been observed on stub sill tank cars for many years. Undetected and unattended, these fractures can develop into a variety of tank car failures. While tank car ruptures are relatively rare, the potential for a catastrophic HAZMAT relea...

  20. Chloride Released from Three Permeable Pavement Surfaces after Winter Salt Application

    EPA Science Inventory

    EPA does not classify chloride as a priority pollutant. It is often unregulated in stormwater runoff but has been a target stressor for Total Maximum Daily Load (TMDL) allotments developed for multiple waterbodies. Previous research has shown that road salt applications increas...

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