Fuel economy of hybrid fuel-cell vehicles

NASA Astrophysics Data System (ADS)

Ahluwalia, Rajesh K.; Wang, X.; Rousseau, A.

The potential improvement in fuel economy of a mid-size fuel-cell vehicle by combining it with an energy storage system has been assessed. An energy management strategy is developed and used to operate the direct hydrogen, pressurized fuel-cell system in a load-following mode and the energy storage system in a charge-sustaining mode. The strategy places highest priority on maintaining the energy storage system in a state where it can supply unanticipated boost power when the fuel-cell system alone cannot meet the power demand. It is found that downsizing a fuel-cell system decreases its efficiency on a drive cycle which is compensated by partial regenerative capture of braking energy. On a highway cycle with limited braking energy the increase in fuel economy with hybridization is small but on the stop-and-go urban cycle the fuel economy can improve by 27%. On the combined highway and urban drive cycles the fuel economy of the fuel-cell vehicle is estimated to increase by up to 15% by hybridizing it with an energy storage system.

Development and review of Euro 5 passenger car emission factors based on experimental results over various driving cycles.

PubMed

Fontaras, Georgios; Franco, Vicente; Dilara, Panagiota; Martini, Giorgio; Manfredi, Urbano

2014-01-15

The emissions of CO2 and regulated pollutants (NOx, HC, CO, PM) of thirteen Euro 5 compliant passenger cars (seven gasoline, six Diesel) were measured on a chassis dynamometer. The vehicles were driven repeatedly over the European type-approval driving cycle (NEDC) and the more dynamic WMTC and CADC driving cycles. Distance-specific emission factors were derived for each pollutant and sub-cycle, and these were subsequently compared to the corresponding emission factors provided by the reference European models used for vehicle emission inventory compilation (COPERT and HBEFA) and put in context with the applicable European emission limits. The measured emissions stayed below the legal emission limits when the type-approval cycle (NEDC) was used. Over the more dynamic cycles (considered more representative of real-world driving) the emissions were consistently higher but in most cases remained below the type-approval limit. The high NOx emissions of Diesel vehicles under real-world driving conditions remain the main cause for environmental concern regarding the emission profile of Euro 5 passenger cars. Measured emissions of NOx exceeded the type-approval limits (up to 5 times in extreme cases) and presented significantly increased average values (0.35 g/km for urban driving and 0.56 g/km for motorway driving). The comparison with the reference models showed good correlation in all cases, a positive finding considering the importance of these tools in emission monitoring and policy-making processes. © 2013. Published by Elsevier B.V. All rights reserved.

Personal exposure to fine particulate air pollution while commuting: An examination of six transport modes on an urban arterial roadway.

PubMed

Chaney, Robert A; Sloan, Chantel D; Cooper, Victoria C; Robinson, Daniel R; Hendrickson, Nathan R; McCord, Tyler A; Johnston, James D

2017-01-01

Traffic-related air pollution in urban areas contributes significantly to commuters' daily PM2.5 exposures, but varies widely depending on mode of commuting. To date, studies show conflicting results for PM2.5 exposures based on mode of commuting, and few studies compare multiple modes of transportation simultaneously along a common route, making inter-modal comparisons difficult. In this study, we examined breathing zone PM2.5 exposures for six different modes of commuting (bicycle, walking, driving with windows open and closed, bus, and light-rail train) simultaneously on a single 2.7 km (1.68 mile) arterial urban route in Salt Lake City, Utah (USA) during peak "rush hour" times. Using previously published minute ventilation rates, we estimated the inhaled dose and exposure rate for each mode of commuting. Mean PM2.5 concentrations ranged from 5.20 μg/m3 for driving with windows closed to 15.21 μg/m3 for driving with windows open. The estimated inhaled doses over the 2.7 km route were 6.83 μg for walking, 2.78 μg for cycling, 1.28 μg for light-rail train, 1.24 μg for driving with windows open, 1.23 μg for bus, and 0.32 μg for driving with windows closed. Similarly, the exposure rates were highest for cycling (18.0 μg/hr) and walking (16.8 μg/hr), and lowest for driving with windows closed (3.7 μg/hr). Our findings support previous studies showing that active commuters receive a greater PM2.5 dose and have higher rates of exposure than commuters using automobiles or public transportation. Our findings also support previous studies showing that driving with windows closed is protective against traffic-related PM2.5 exposure.

Personal exposure to fine particulate air pollution while commuting: An examination of six transport modes on an urban arterial roadway

PubMed Central

Sloan, Chantel D.; Cooper, Victoria C.; Robinson, Daniel R.; Hendrickson, Nathan R.; McCord, Tyler A.; Johnston, James D.

2017-01-01

Traffic-related air pollution in urban areas contributes significantly to commuters’ daily PM2.5 exposures, but varies widely depending on mode of commuting. To date, studies show conflicting results for PM2.5 exposures based on mode of commuting, and few studies compare multiple modes of transportation simultaneously along a common route, making inter-modal comparisons difficult. In this study, we examined breathing zone PM2.5 exposures for six different modes of commuting (bicycle, walking, driving with windows open and closed, bus, and light-rail train) simultaneously on a single 2.7 km (1.68 mile) arterial urban route in Salt Lake City, Utah (USA) during peak “rush hour” times. Using previously published minute ventilation rates, we estimated the inhaled dose and exposure rate for each mode of commuting. Mean PM2.5 concentrations ranged from 5.20 μg/m3 for driving with windows closed to 15.21 μg/m3 for driving with windows open. The estimated inhaled doses over the 2.7 km route were 6.83 μg for walking, 2.78 μg for cycling, 1.28 μg for light-rail train, 1.24 μg for driving with windows open, 1.23 μg for bus, and 0.32 μg for driving with windows closed. Similarly, the exposure rates were highest for cycling (18.0 μg/hr) and walking (16.8 μg/hr), and lowest for driving with windows closed (3.7 μg/hr). Our findings support previous studies showing that active commuters receive a greater PM2.5 dose and have higher rates of exposure than commuters using automobiles or public transportation. Our findings also support previous studies showing that driving with windows closed is protective against traffic-related PM2.5 exposure. PMID:29121096

MERCURY EMISSIONS FROM BRAKE WEAR ASSOCIATED WITH ON-ROAD VEHICLES

EPA Science Inventory

This paper will focus on brake wear emissions of mercury and trace metals collected from 16 in-use light-duty vehicles (14 gasoline and 2 diesel) on a chassis dynamometer over the course of urban drive cycles.

An assessment of the real-world driving gaseous emissions from a Euro 6 light-duty diesel vehicle using a portable emissions measurement system (PEMS)

NASA Astrophysics Data System (ADS)

Luján, José M.; Bermúdez, Vicente; Dolz, Vicente; Monsalve-Serrano, Javier

2018-02-01

Recent investigations demonstrated that real-world emissions usually exceed the levels achieved in the laboratory based type approval processes. By means of on-board emissions measurements, it has been shown that nitrogen oxides emitted by diesel engines substantially exceed the limit imposed by the Euro 6 regulation. Thus, with the aim of complementing the worldwide harmonized light vehicles test cycle, the real driving emissions cycle will be introduced after 1 September 2017 to regulate the vehicle emissions in real-world driving situations. This paper presents on-board gaseous emissions measurements from a Euro 6 light-duty diesel vehicle in a real-world driving route using a portable emissions measurement system. The test route characteristics follow the requirements imposed by the RDE regulation. The analysis of the raw emissions results suggests that the greatest amount of nitrogen oxides and nitrogen dioxide are emitted during the urban section of the test route, confirming that lower speeds with more accelerations and decelerations lead to higher nitrogen oxides emissions levels than constant high speeds. Moreover, the comparison of the two calculation methods proposed by the real driving emissions regulation has revealed emissions rates differences ranging from 10% to 45% depending on the pollutant emission and the trip section considered (urban or total). Thus, the nitrogen oxides emissions conformity factor slightly varies from one method to the other.

Ultrafine particle exposures while walking, cycling, and driving along an urban residential roadway

NASA Astrophysics Data System (ADS)

Quiros, David C.; Lee, Eon S.; Wang, Rui; Zhu, Yifang

2013-07-01

Elevated concentrations of ultrafine particles (UFPs, <0.1 μm), which have been linked to adverse health effects, are commonly found along roadways. This study reports UFP and PM2.5 concentrations and respiratory exposures among four transportation modes on an urban residential street in Santa Monica, California while walking, cycling, and driving with windows open and windows closed (with air recirculation on). Repeated measurements were made for nine days during morning (7:30-9:30), afternoon (12:30-14:30), and evening (17:00-19:00) periods. Median UFP concentrations ranged 1-3 × 104 particles cm-3, were 70% lower in afternoon or evening periods compared to the morning, and were 60% lower when driving with windows closed than open. Median PM2.5 ranged 2-15 μg m-3, well below the annual National Ambient Air Quality standard of 15 μg m-3. Respiratory UFP exposure (particles inhaled trip-1) was ˜2 times higher while driving with windows open, ˜15 times higher when cycling, and ˜30 times higher walking, than driving with windows closed. During one evening session with perpendicular rather than parallel wind conditions, absolute UFP concentration was 80% higher, suggesting influence of off-roadway sources. Under parallel wind conditions, a parameter called emissions-weighted traffic volume, used to account for higher and lower emitting vehicles, was correlated with beach-site-subtracted UFP using second-order polynomial model (R2 = 0.61). Based on this model, an 83% on-roadway UFP reduction could be achieved by (1) requiring all trucks to meet California 2007 model-year engine standards, (2) reducing light-duty vehicle flows by 25%, and (3) replacing high-emitting light-duty vehicles (pre 1978) with newer 2010 fleet-average vehicles.

Laboratory testing of airborne brake wear particle emissions using a dynamometer system under urban city driving cycles

NASA Astrophysics Data System (ADS)

Hagino, Hiroyuki; Oyama, Motoaki; Sasaki, Sousuke

2016-04-01

To measure driving-distance-based mass emission factors for airborne brake wear particulate matter (PM; i.e., brake wear particles) related to the non-asbestos organic friction of brake assembly materials (pads and lining), and to characterize the components of brake wear particles, a brake wear dynamometer with a constant-volume sampling system was developed. Only a limited number of studies have investigated brake emissions under urban city driving cycles that correspond to the tailpipe emission test (i.e., JC08 or JE05 mode of Japanese tailpipe emission test cycles). The tests were performed using two passenger cars and one middle-class truck. The observed airborne brake wear particle emissions ranged from 0.04 to 1.4 mg/km/vehicle for PM10 (particles up to 10 μm (in size), and from 0.04 to 1.2 mg/km/vehicle for PM2.5. The proportion of brake wear debris emitted as airborne brake wear particles was 2-21% of the mass of wear. Oxygenated carbonaceous components were included in the airborne PM but not in the original friction material, which indicates that changes in carbon composition occurred during the abrasion process. Furthermore, this study identified the key tracers of brake wear particles (e.g., Fe, Cu, Ba, and Sb) at emission levels comparable to traffic-related atmospheric environments.

Elements and polycyclic aromatic hydrocarbons in exhaust particles emitted by light-duty vehicles.

PubMed

Alves, Célia A; Barbosa, Cátia; Rocha, Sónia; Calvo, Ana; Nunes, Teresa; Cerqueira, Mário; Pio, Casimiro; Karanasiou, Angeliki; Querol, Xavier

2015-08-01

The main purpose of this work was to evaluate the chemical composition of particulate matter (PM) emitted by eight different light-duty vehicles. Exhaust samples from petrol and diesel cars (Euro 3 to Euro 5) were collected in a chassis dynamometer facility. To simulate the real-world driving conditions, three ARTEMIS cycles were followed: road, to simulate a fluid traffic flow and urban with hot and cold starts, to simulate driving conditions in cities. Samples were analysed for the water-soluble ions, for the elemental composition and for polycyclic aromatic hydrocarbons (PAHs), respectively, by ion chromatography, inductively coupled plasma atomic emission spectroscopy (ICP-AES), inductively coupled plasma mass spectrometry (ICP-MS) and gas chromatography-mass spectrometry (GC-MS). Nitrate and phosphate were the major water-soluble ions in the exhaust particles emitted from diesel and petrol vehicles, respectively. The amount of material emitted is affected by the vehicle age. For vehicles ≥Euro 4, most elements were below the detection limits. Sodium, with emission factors in the ranges 23.5-62.4 and 78.2-227μg km(-1), for petrol and diesel Euro 3 vehicles, respectively, was the major element. The emission factors of metallic elements indicated that diesel vehicles release three to five times more than petrol automobiles. Element emissions under urban cycles are higher than those found for on-road driving, being three or four times higher, for petrol vehicles, and two or three times, for diesel vehicles. The difference between cycles is mainly due to the high emissions for the urban cycle with hot start-up. As registered for elements, most of the PAH emissions for vehicles ≥Euro 4 were also below the detection limits. Regardless of the vehicle models or driving cycles, the two- to four-ring PAHs were always dominant. Naphthalene, with emission factors up to 925 μg km(-1), was always the most abundant PAH. The relative cancer risk associated with naphthalene was estimated to be up to several orders of magnitude higher than any of the chemical species found in the PM phase. The highest PAH emission factors were registered for diesel-powered vehicles. The condition of the vehicle can exert a decisive influence on both element and PAH emissions.

Air toxic emissions from passenger cars operating on ethanol blend gasoline

EPA Science Inventory

Emissions of gaseous and particulate contaminants have been characterized during the operation of two flex-fuel and one non-flex-fueled light-duty vehicle. These vehicles were operated on a chassis dynamometer using a driving cycle representative of urban conditions while burning...

Analysis of a diesel-electric hybrid urban bus system

NASA Astrophysics Data System (ADS)

Marr, W. W.; Sekar, R. R.; Ahlheim, M. C.

A hybrid bus powered by a diesel engine and a battery pack was analyzed over an idealized bus-driving cycle in Chicago. Three hybrid configurations, two parallel and one series, were evaluated. The results indicate that the fuel economy of a hybrid bus, taking into account the regenerative braking, is comparable with that of a conventional diesel bus. Life-cycle costs are slightly higher because of the added weight and cost of the battery.

Toward reconciling instantaneous roadside measurements of light duty vehicle exhaust emissions with type approval driving cycles.

PubMed

Rhys-Tyler, Glyn A; Bell, Margaret C

2012-10-02

A method is proposed to relate essentially instantaneous roadside measurements of vehicle exhaust emissions, with emission results generated over a type approval driving cycle. An urban remote sensing data set collected in 2008 is used to define the dynamic relationship between vehicle specific power and exhaust emissions, across a range of vehicle ages, engine capacities, and fuel types. The New European Driving Cycle is synthesized from the remote sensing data using vehicle specific power to characterize engine load, and the results compared with official published emissions data from vehicle type approval tests over the same driving cycle. Mean carbon monoxide emissions from gasoline-powered cars ≤ 3 years old measured using remote sensing are found to be 1.3 times higher than published original type approval test values; this factor increases to 2.2 for cars 4-8 years old, and 6.4 for cars 9-12 years old. The corresponding factors for diesel cars are 1.1, 1.4, and 1.2, respectively. Results for nitric oxide, hydrocarbons, and particulate matter are also reported. The findings have potential implications for the design of traffic management interventions aimed at reducing emissions, fleet inspection and maintenance programs, and the specification of vehicle emission models.

Secondary organic aerosol production from diesel vehicle exhaust: impact of aftertreatment, fuel chemistry and driving cycle

NASA Astrophysics Data System (ADS)

Gordon, T. D.; Presto, A. A.; Nguyen, N. T.; Robertson, W. H.; Na, K.; Sahay, K. N.; Zhang, M.; Maddox, C.; Rieger, P.; Chattopadhyay, S.; Maldonado, H.; Maricq, M. M.; Robinson, A. L.

2014-05-01

Environmental chamber ("smog chamber") experiments were conducted to investigate secondary organic aerosol (SOA) production from dilute emissions from two medium-duty diesel vehicles (MDDVs) and three heavy-duty diesel vehicles (HDDVs) under urban-like conditions. Some of the vehicles were equipped with emission control aftertreatment devices, including diesel particulate filters (DPFs), selective catalytic reduction (SCR) and diesel oxidation catalysts (DOCs). Experiments were also performed with different fuels (100% biodiesel and low-, medium- or high-aromatic ultralow sulfur diesel) and driving cycles (Unified Cycle,~Urban Dynamometer Driving Schedule, and creep + idle). During normal operation, vehicles with a catalyzed DPF emitted very little primary particulate matter (PM). Furthermore, photooxidation of dilute emissions from these vehicles produced essentially no SOA (below detection limit). However, significant primary PM emissions and SOA production were measured during active DPF regeneration experiments. Nevertheless, under reasonable assumptions about DPF regeneration frequency, the contribution of regeneration emissions to the total vehicle emissions is negligible, reducing PM trapping efficiency by less than 2%. Therefore, catalyzed DPFs appear to be very effective in reducing both primary PM emissions and SOA production from diesel vehicles. For both MDDVs and HDDVs without aftertreatment substantial SOA formed in the smog chamber - with the emissions from some vehicles generating twice as much SOA as primary organic aerosol after 3 h of oxidation at typical urban VOC / NOx ratios (3 : 1). Comprehensive organic gas speciation was performed on these emissions, but less than half of the measured SOA could be explained by traditional (speciated) SOA precursors. The remainder presumably originates from the large fraction (~30%) of the nonmethane organic gas emissions that could not be speciated using traditional one-dimensional gas chromatography. The unspeciated organics - likely comprising less volatile species such as intermediate volatility organic compounds - appear to be important SOA precursors; we estimate that the effective SOA yield (defined as the ratio of SOA mass to reacted precursor mass) was 9 ± 6% if both speciated SOA precursors and unspeciated organics are included in the analysis. SOA production from creep + idle operation was 3-4 times larger than SOA production from the same vehicle operated over the Urban Dynamometer Driving Schedule (UDDS). Fuel properties had little or no effect on primary PM emissions or SOA formation.

Secondary organic aerosol production from diesel vehicle exhaust: impact of aftertreatment, fuel chemistry and driving cycle

NASA Astrophysics Data System (ADS)

Gordon, T. D.; Presto, A. A.; Nguyen, N. T.; Robertson, W. H.; Na, K.; Sahay, K. N.; Zhang, M.; Maddox, C.; Rieger, P.; Chattopadhyay, S.; Maldonado, H.; Maricq, M. M.; Robinson, A. L.

2013-09-01

Environmental chamber ("smog chamber") experiments were conducted to investigate secondary organic aerosol (SOA) production from dilute emissions from two medium-duty diesel vehicles (MDDVs) and three heavy-duty diesel vehicles (HDDVs) under urban-like conditions. Some of the vehicles were equipped with emission control aftertreatment devices including diesel particulate filters (DPF), selective catalytic reduction (SCR) and diesel oxidation catalysts (DOC). Experiments were also performed with different fuels (100% biodiesel and low-, medium- or high-aromatic ultralow sulfur diesel) and driving cycles (Unified Cycle, Urban Dynamometer Driving Schedule, and creep+idle). During normal operation, vehicles with a catalyzed DPF emitted very little primary particulate matter (PM). Furthermore, photo-oxidation of dilute emissions from these vehicles produced essentially no SOA (below detection limit). However, significant primary PM emissions and SOA production were measured during active DPF regeneration experiments. Nevertheless, under reasonable assumptions about DPF regeneration frequency, the contribution of regeneration emissions to the total vehicle emissions is negligible, reducing PM trapping efficiency by less than 2%. Therefore, catalyzed DPFs appear to be very effective in reducing both primary and secondary fine particulate matter from diesel vehicles. For both MDDVs and HDDVs without aftertreatment substantial SOA formed in the smog chamber - with the emissions from some vehicles generating twice as much SOA as primary organic aerosol after three hours of oxidation at typical urban VOC : NOx ratios (3:1). Comprehensive organic gas speciation was performed on these emissions, but less than half of the measured SOA could be explained by traditional (speciated) SOA precursors. The remainder presumably originates from the large fraction (~30%) of the non-methane organic gas emissions that could not be speciated using traditional one-dimensional gas-chromatography. The unspeciated organics - likely comprising less volatile species, such as intermediate volatility organic compounds - appear to be important SOA precursors; we estimate that the effective SOA yield (defined as the ratio of SOA mass to reacted precursor mass) was 9 ± 6% if both speciated SOA precursors and unspeciated organics are included in the analysis. SOA production from creep+idle operation was 3-4 times larger than SOA production from the same vehicle operated over the Urban Dynamometer Driving Schedule (UDDS). Fuel properties had little or no effect on primary PM emissions or SOA formation.

Development of Hot Exhaust Emission Factors for Iranian-Made Euro-2 Certified Light-Duty Vehicles.

PubMed

Banitalebi, Ehsan; Hosseini, Vahid

2016-01-05

Emission factors (EFs) are fundamental, necessary data for air pollution research and scenario implementation. With the vision of generating national EFs of the Iranian transportation system, a portable emission measurement system (PEMS) was used to develop the basic EFs for a statistically significant sample of Iranian gasoline-fueled privately owned light duty vehicles (LDVs) operated in Tehran. A smaller sample size of the same fleet was examined by chassis dynamometer (CD) bag emission measurement tests to quantify the systematic differences between the PEMS and CD methods. The selected fleet was tested over four different routes of uphill highways, flat highways, uphill urban streets, and flat urban streets. Real driving emissions (RDEs) and fuel consumption (FC) rates were calculated by weighted averaging of the results from each route. The activity of the fleet over each route type was assumed as a weighting factor. The activity data were obtained from a Tehran traffic model. The RDEs of the selected fleet were considerably higher than the certified emission levels of all vehicles. Differences between Tehran real driving cycles and the New European Driving Cycle (NEDC) was attributed to the lower loading of NEDC. A table of EFs based on RDEs was developed for the sample fleet.

Understanding bicycling in cities using system dynamics modelling.

PubMed

Macmillan, Alexandra; Woodcock, James

2017-12-01

Increasing urban bicycling has established net benefits for human and environmental health. Questions remain about which policies are needed and in what order, to achieve an increase in cycling while avoiding negative consequences. Novel ways of considering cycling policy are needed, bringing together expertise across policy, community and research to develop a shared understanding of the dynamically complex cycling system. In this paper we use a collaborative learning process to develop a dynamic causal model of urban cycling to develop consensus about the nature and order of policies needed in different cycling contexts to optimise outcomes. We used participatory system dynamics modelling to develop causal loop diagrams (CLDs) of cycling in three contrasting contexts: Auckland, London and Nijmegen. We combined qualitative interviews and workshops to develop the CLDs. We used the three CLDs to compare and contrast influences on cycling at different points on a "cycling trajectory" and drew out policy insights. The three CLDs consisted of feedback loops dynamically influencing cycling, with significant overlap between the three diagrams. Common reinforcing patterns emerged: growing numbers of people cycling lifts political will to improve the environment; cycling safety in numbers drives further growth; and more cycling can lead to normalisation across the population. By contrast, limits to growth varied as cycling increases. In Auckland and London, real and perceived danger was considered the main limit, with added barriers to normalisation in London. Cycling congestion and "market saturation" were important in the Netherlands. A generalisable, dynamic causal theory for urban cycling enables a more ordered set of policy recommendations for different cities on a cycling trajectory. Participation meant the collective knowledge of cycling stakeholders was represented and triangulated with research evidence. Extending this research to further cities, especially in low-middle income countries, would enhance generalizability of the CLDs.

Electro-thermal analysis of Lithium Iron Phosphate battery for electric vehicles

NASA Astrophysics Data System (ADS)

Saw, L. H.; Somasundaram, K.; Ye, Y.; Tay, A. A. O.

2014-03-01

Lithium ion batteries offer an attractive solution for powering electric vehicles due to their relatively high specific energy and specific power, however, the temperature of the batteries greatly affects their performance as well as cycle life. In this work, an empirical equation characterizing the battery's electrical behavior is coupled with a lumped thermal model to analyze the electrical and thermal behavior of the 18650 Lithium Iron Phosphate cell. Under constant current discharging mode, the cell temperature increases with increasing charge/discharge rates. The dynamic behavior of the battery is also analyzed under a Simplified Federal Urban Driving Schedule and it is found that heat generated from the battery during this cycle is negligible. Simulation results are validated with experimental data. The validated single cell model is then extended to study the dynamic behavior of an electric vehicle battery pack. The modeling results predict that more heat is generated on an aggressive US06 driving cycle as compared to UDDS and HWFET cycle. An extensive thermal management system is needed for the electric vehicle battery pack especially during aggressive driving conditions to ensure that the cells are maintained within the desirable operating limits and temperature uniformity is achieved between the cells.

10 CFR 474.4 - Test procedures.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 3 2011-01-01 2011-01-01 false Test procedures. 474.4 Section 474.4 Energy DEPARTMENT OF...; PETROLEUM-EQUIVALENT FUEL ECONOMY CALCULATION § 474.4 Test procedures. (a) The electric vehicle energy... Schedule and Urban Dynamometer Driving Schedule test cycles at 40 CFR parts 86 and 600. (b) The “Special...

Hybrid cars now, fuel cell cars later.

PubMed

Demirdöven, Nurettin; Deutch, John

2004-08-13

We compare the energy efficiency of hybrid and fuel cell vehicles as well as conventional internal combustion engines. Our analysis indicates that fuel cell vehicles using hydrogen from fossil fuels offer no significant energy efficiency advantage over hybrid vehicles operating in an urban drive cycle. We conclude that priority should be placed on hybrid vehicles by industry and government.

Hybrid Cars Now, Fuel Cell Cars Later

NASA Astrophysics Data System (ADS)

Demirdöven, Nurettin; Deutch, John

2004-08-01

We compare the energy efficiency of hybrid and fuel cell vehicles as well as conventional internal combustion engines. Our analysis indicates that fuel cell vehicles using hydrogen from fossil fuels offer no significant energy efficiency advantage over hybrid vehicles operating in an urban drive cycle. We conclude that priority should be placed on hybrid vehicles by industry and government.

Development and application of a mobile laboratory for measuring emissions from diesel engines. 1. Regulated gaseous emissions.

PubMed

Cocker, David R; Shah, Sandip D; Johnson, Kent; Miller, J Wayne; Norbeck, Joseph M

2004-04-01

Information about in-use emissions from diesel engines remains a critical issue for inventory development and policy design. Toward that end, we have developed and verified the first mobile laboratory that measures on-road or real-world emissions from engines at the quality level specified in the U.S. Congress Code of Federal Regulations. This unique mobile laboratory provides information on integrated and modal regulated gaseous emission rates and integrated emission rates for speciated volatile and semivolatile organic compounds and particulate matter during real-world operation. Total emissions are captured and collected from the HDD vehicle that is pulling the mobile laboratory. While primarily intended to accumulate data from HDD vehicles, it may also be used to measure emission rates from stationary diesel sources such as back-up generators. This paper describes the development of the mobile laboratory, its measurement capabilities, and the verification process and provides the first data on total capture gaseous on-road emission measurements following the California Air Resources Board (ARB) 4-mode driving cycle, the hot urban dynamometer driving schedule (UDDS), the modified 5-mode cycle, and a 53.2-mi highway chase experiment. NOx mass emission rates (g mi(-1)) for the ARB 4-mode driving cycle, the hot UDDS driving cycle, and the chase experimentwerefoundto exceed current emission factor estimates for the engine type tested by approximately 50%. It was determined that congested traffic flow as well as "off-Federal Test Procedure cycle" emissions can lead to significant increases in per mile NOx emission rates for HDD vehicles.

Characterizing emission rates of regulated pollutants from model year 2012+ heavy-duty diesel vehicles equipped with DPF and SCR systems.

PubMed

Jiang, Yu; Yang, Jiacheng; Cocker, David; Karavalakis, Georgios; Johnson, Kent C; Durbin, Thomas D

2018-04-01

The regulated emissions of five 2012 and newer, low-mileage, heavy-duty Class 8 diesel trucks equipped with diesel particulate filters (DPFs) and selective catalytic reduction (SCR) systems were evaluated over test cycles representing urban, highway, and stop-and-go driving on a chassis dynamometer. NOx emissions over the Urban Dynamometer Driving Schedule (UDDS) ranged from 0.495 to 1.363g/mi (0.136 to 0.387g/bhp-hr) for four of the normal emitting trucks. For those trucks, NOx emissions were lowest over the cruise (0.068 to 0.471g/mi) and high-speed cruise (0.067 to 0.249g/mi) cycles, and highest for the creep cycle (2.131 to 9.468g/mi). A fifth truck showed an anomaly in that it had never regenerated throughout its relatively short operating lifetime due to its unusual, unladed service history. This truck exhibited NOx emissions of 3.519g/mi initially over the UDDS, with UDDS NOx emissions decreasing to 0.39g/mi after a series of parked regenerations. PM, THC, and CO emissions were found to be very low for most of the testing conditions, due to the presence of the DPF/SCR aftertreatment system, and were comparable to background levels in some cases. Copyright © 2017 Elsevier B.V. All rights reserved.

Carbonaceous PM2.5 emitted from light-duty vehicles operating on low-level ethanol fuel blends.

EPA Science Inventory

This study aims to examine carbonaceous aerosol emissions from three Tier 2-certified 2008 model year LDVs burning e0, e10, and e85 fuel blends at -7°C and 24°C. The LDVs were tested on an electric chasis dynamometer using the LA-92 Urban Driving Cycle (UDC). Exhaust was ...

Does intrinsic light heterogeneity in Ricinus communis L. monospecific thickets drive species' population dynamics?

PubMed

Goyal, Neha; Shah, Kanhaiya; Sharma, Gyan Prakash

2018-06-19

Ricinus communis L. colonizes heterogeneous urban landscapes as monospecific thickets. The ecological understanding on colonization success of R. communis population due to variable light availability is lacking. Therefore, to understand the effect of intrinsic light heterogeneity on species' population dynamics, R. communis populations exposed to variable light availability (low, intermediate, and high) were examined for performance strategies through estimation of key vegetative, eco-physiological, biochemical, and reproductive traits. Considerable variability existed in studied plant traits in response to available light. Individuals inhabiting high-light conditions exhibited high eco-physiological efficiency and reproductive performance that potentially confers population boom. Individuals exposed to low light showed poor performance in terms of eco-physiology and reproduction, which attribute to bust. However, individuals in intermediate light were observed to be indeterminate to light availability, potentially undergoing trait modulations with uncertainty of available light. Heterogeneous light availability potentially drives the boom and bust cycles in R. communis monospecific thickets. Such boom and bust cycles subsequently affect species' dominance, persistence, collapse, and/or resurgence as an aggressive colonizer in contrasting urban environments. The study fosters extensive monitoring of R. communis thickets to probe underlying mechanism(s) affecting expansions and/or collapses of colonizing populations.

Urban driven phenotypic changes: empirical observations and theoretical implications for eco-evolutionary feedback

PubMed Central

Marzluff, John

2017-01-01

Emerging evidence that cities drive micro-evolution raises the question of whether rapid urbanization of Earth might impact ecosystems by causing systemic changes in functional traits that regulate urban ecosystems' productivity and stability. Intraspecific trait variation—variation in organisms' morphological, physiological or behavioural characteristics stemming from genetic variability and phenotypic plasticity—has significant implications for ecological functions such as nutrient cycling and primary productivity. While it is well established that changes in ecological conditions can drive evolutionary change in species' traits that, in turn, can alter ecosystem function, an understanding of the reciprocal and simultaneous processes associated with such interactions is only beginning to emerge. In urban settings, the potential for rapid trait change may be exacerbated by multiple selection pressures operating simultaneously. This paper reviews evidence on mechanisms linking urban development patterns to rapid phenotypic changes, and differentiates phenotypic changes for which there is evidence of micro-evolution versus phenotypic changes which may represent plasticity. Studying how humans mediate phenotypic trait changes through urbanization could shed light on fundamental concepts in ecological and evolutionary theory. It can also contribute to our understanding of eco-evolutionary feedback and provide insights for maintaining ecosystem function over the long term. This article is part of the themed issue ‘Human influences on evolution, and the ecological and societal consequences’. PMID:27920374

TTI (Texas Transportation Institute) track/dynamometer study. Final report

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

Reineman, M.; Thompson, G.

1983-01-01

Seven passenger cars and one light truck were operated over the EPA urban and highway driving cycles to compare fuel economy measurements obtained on a test track with the fuel economy results obtained on a chassis dynamometer. The test program was designed to duplicate, as closely as possible, the track force loading (as determined by standard EPA road coastdown procedures) on the dynamometer. Experimental parameters which were investigated included loading differences between front- and rear-wheel drive vehicles, volumetric versus carbon balance fuel measurement techniques, coupled versus uncoupled roll dynamometer tests, and curved track versus straight track coastdowns.

Drive cycle analysis of butanol/diesel blends in a light-duty vehicle.

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

Miers, S. A.; Carlson, R. W.; McConnell, S. S.

2008-10-01

The potential exists to displace a portion of the petroleum diesel demand with butanol and positively impact engine-out particulate matter. As a preliminary investigation, 20% and 40% by volume blends of butanol with ultra low sulfur diesel fuel were operated in a 1999 Mercedes Benz C220 turbo diesel vehicle (Euro III compliant). Cold and hot start urban as well as highway drive cycle tests were performed for the two blends of butanol and compared to diesel fuel. In addition, 35 MPH and 55 MPH steady-state tests were conducted under varying road loads for the two fuel blends. Exhaust gas emissions,more » fuel consumption, and intake and exhaust temperatures were acquired for each test condition. Filter smoke numbers were also acquired during the steady-state tests.« less

Fuel economy and exhaust emissions characteristics of diesel vehicles: Test results of a prototype Chrysler Volare, 225 CID (3.7-liter) automobile

NASA Technical Reports Server (NTRS)

Walter, R. A.

1982-01-01

The results obtained from fuel economy and emission tests conducted on a prototype Chrysler Volare diesel vehicle are documented. The vehicle was tested on a chassis dynamometer over selected drive cycles and steady-state conditions. The fuel used, was a DOE/BETC referee fuel. Particulate emission rates were calculated from dilution tunnel measurements and large volume particulate samples were collected for biological and chemical analysis. The vehicle obtained 32.7 mpg for the FTP urban cycle and 48.8 mpg for the highway cycle. The emissions rates were 0.42/1.58/1.17/0.28 g/mile of HC, CO, NOx and particulates respectively.

Variability in operation-based NO(x) emission factors with different test routes, and its effects on the real-driving emissions of light diesel vehicles.

PubMed

Lee, Taewoo; Park, Junhong; Kwon, Sangil; Lee, Jongtae; Kim, Jeongsoo

2013-09-01

The objective of this study is to quantify the differences in NO(x) emissions between standard and non-standard driving and vehicle operating conditions, and to estimate by how much NO(x) emissions exceed the legislative emission limits under typical Korean road traffic conditions. Twelve Euro 3-5 light-duty diesel vehicles (LDDVs) manufactured in Korea were driven on a chassis dynamometer over the standard New European Driving Cycle (NEDC) and a representative Korean on-road driving cycle (KDC). NO(x) emissions, average speeds and accelerations were calculated for each 1-km trip segment, so called averaging windows. The results suggest that the NO(x) emissions of the tested vehicles are more susceptible to variations in the driving cycles than to those in the operating conditions. Even under comparable operating conditions, the NO(x) control capabilities of vehicles differ from each other, i.e., NO(x) control is weaker for the KDC than for the NEDC. The NO(x) emissions over the KDC for given vehicle operating conditions exceed those over the NEDC by more than a factor of 8. Consequently, on-road NO(x) emission factors are estimated here to exceed the Euro 5 emission limit by up to a factor of 8, 4 and 3 for typical Korean urban, rural, and motorway road traffic conditions, respectively. Our findings support the development of technical regulations for supplementary real-world emission tests for emission certification and the corresponding research actions taken by automotive industries. Copyright © 2013 Elsevier B.V. All rights reserved.

Improved SCR ac Motor Controller for Battery Powered Urban Electric Vehicles

NASA Technical Reports Server (NTRS)

Latos, T. S.

1982-01-01

An improved ac motor controller, which when coupled to a standard ac induction motor and a dc propulsion battery would provide a complete electric vehicle power train with the exception of the mechanical transmission and drive wheels was designed. In such a system, the motor controller converts the dc electrical power available at the battery terminals to ac electrical power for the induction motor in response to the drivers commands. The performance requirements of a hypothetical electric vehicle with an upper weight bound of 1590 kg (3500 lb) were used to determine the power rating of the controller. Vehicle acceleration capability, top speed, and gradeability requisites were contained in the Society of Automotive Engineers (SAE) Schedule 227a(d) driving cycle. The important capabilities contained in this driving cycle are a vehicle acceleration requirement of 0 to 72.4 kmph (0 to 45 mph) in 28 seconds a top speed of 88.5 kmph (55 mph), and the ability to negotiate a 10% grade at 48 kmph (30 mph). A 10% grade is defined as one foot of vertical rise per 10 feet of horizontal distance.

Interacting Physical and Biological Processes Affecting Nutrient Transport Through Human Dominated Landscapes

NASA Astrophysics Data System (ADS)

Finlay, J. C.

2015-12-01

Human activities increasingly dominate biogeochemical cycles of limiting nutrients on Earth. Urban and agricultural landscapes represent the largest sources of excess nutrients that drive water quality degradation. The physical structure of both urban and agricultural watersheds has been extensively modified, and these changes have large impacts on water and nutrient transport. Despite strong physical controls over nutrient transport in human dominated landscapes, biological processes play important roles in determining the fates of both nitrogen and phosphorus. This talk uses examples from research in urban and agricultural watersheds in the Midwestern USA to illustrate interactions of physical and biological controls over nutrient cycles that have shifted nitrogen (N) and phosphorus (P) sources and cycling in unexpected ways in response to management changes. In urban watersheds, efforts to improve water quality have been hindered by legacy sources of phosphorus added to storm water through transport to drainage systems by vegetation. Similarly, reductions in field erosion in agricultural watersheds have not led to major reductions in phosphorus transport, because of continued release of biological sources of P. Where management of phosphorus has been most effective in reducing eutrophication of lakes, decreases in N removal processes have led to long term increases in N concentration and transport. Together, these examples show important roles for biological processes affecting nutrient movement in highly modified landscapes. Consideration of the downstream physical and biological responses of management changes are thus critical toward identification of actions that will most effectively reduce excess nutrients watersheds and coastal zones.

Comparison of particle mass and solid particle number (SPN) emissions from a heavy-duty diesel vehicle under on-road driving conditions and a standard testing cycle.

PubMed

Zheng, Zhongqing; Durbin, Thomas D; Xue, Jian; Johnson, Kent C; Li, Yang; Hu, Shaohua; Huai, Tao; Ayala, Alberto; Kittelson, David B; Jung, Heejung S

2014-01-01

It is important to understand the differences between emissions from standard laboratory testing cycles and those from actual on-road driving conditions, especially for solid particle number (SPN) emissions now being regulated in Europe. This study compared particle mass and SPN emissions from a heavy-duty diesel vehicle operating over the urban dynamometer driving schedule (UDDS) and actual on-road driving conditions. Particle mass emissions were calculated using the integrated particle size distribution (IPSD) method and called MIPSD. The MIPSD emissions for the UDDS and on-road tests were more than 6 times lower than the U.S. 2007 heavy-duty particulate matter (PM) mass standard. The MIPSD emissions for the UDDS fell between those for the on-road uphill and downhill driving. SPN and MIPSD measurements were dominated by nucleation particles for the UDDS and uphill driving and by accumulation mode particles for cruise and downhill driving. The SPN emissions were ∼ 3 times lower than the Euro 6 heavy-duty SPN limit for the UDDS and downhill driving and ∼ 4-5 times higher than the Euro 6 SPN limit for the more aggressive uphill driving; however, it is likely that most of the "solid" particles measured under these conditions were associated with a combination release of stored sulfates and enhanced sulfate formation associated with high exhaust temperatures, leading to growth of volatile particles into the solid particle counting range above 23 nm. Except for these conditions, a linear relationship was found between SPN and accumulation mode MIPSD. The coefficient of variation (COV) of SPN emissions of particles >23 nm ranged from 8 to 26% for the UDDS and on-road tests.

Driving factors of urban land growth in Guangzhou and its implications for sustainable development

NASA Astrophysics Data System (ADS)

Cui, Xuezhu; Li, Shaoying; Wang, Xuetong; Xue, Xiaolong

2018-04-01

Since 2000, China's urban land has expanded at a dramatic speed because of the country's rapid urbanization. The country has been experiencing unbalanced development between rural and urban areas, causing serious challenges such as agricultural security and land resources waste. Effectively evaluating the driving factors of urban land growth is essential for improving efficient land use management and sustainable urban development. This study established a principal component regression model based on eight indicators to identify their influences on urban land growth in Guangzhou. The results provided a grouping analysis of the driving factors, and found that economic growth, urban population, and transportation development are the driving forces of urban land growth of Guangzhou, while the tertiary industry has an opposite effect. The findings led to further suggestions and recommendations for urban sustainable development. Hence, local governments should design relevant policies for achieving the rational development of urban land use and strategic planning on urban sustainable development.

Light-Duty Drive Cycle Simulations of Diesel Engine-Out Exhaust Properties for an RCCI-Enabled Vehicle

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

Gao, Zhiming; Curran, Scott; Daw, C Stuart

2013-01-01

In-cylinder blending of gasoline and diesel fuels to achieve low-temperature reactivity controlled compression ignition (RCCI) can reduce NOx and PM emissions while maintaining or improving brake thermal efficiency compared to conventional diesel combustion (CDC). Moreover, the dual-fueling RCCI is able to achieve these benefits by tailoring combustion reactivity over a wider range of engine operation than is possible with a single fuel. However, the currently demonstrated range of stable RCCI combustion just covers a portion of the engine speed-load range required in several light-duty drive cycles. This means that engines must switch from RCCI to CDC when speed and loadmore » fall outside of the stable RCCI range. In this study we investigated the impact of RCCI as it has recently been demonstrated on practical engine-out exhaust temperature and emissions by simulating a multi-mode RCCI-enabled vehicle operating over two urban and two highway driving cycles. To implement our simulations, we employed experimental engine maps for a multi-mode RCCI/CDC engine combined with a standard mid-size, automatic transmission, passenger vehicle in the Autonomie vehicle simulation platform. Our results include both detailed transient and cycle-averaged engine exhaust temperature and emissions for each case, and we note the potential implications of the modified exhaust properties on catalytic emissions control and utilization of waste heat recovery on future RCCI-enabled vehicles.« less

Autonomous driving in urban environments: approaches, lessons and challenges.

PubMed

Campbell, Mark; Egerstedt, Magnus; How, Jonathan P; Murray, Richard M

2010-10-13

The development of autonomous vehicles for urban driving has seen rapid progress in the past 30 years. This paper provides a summary of the current state of the art in autonomous driving in urban environments, based primarily on the experiences of the authors in the 2007 DARPA Urban Challenge (DUC). The paper briefly summarizes the approaches that different teams used in the DUC, with the goal of describing some of the challenges that the teams faced in driving in urban environments. The paper also highlights the long-term research challenges that must be overcome in order to enable autonomous driving and points to opportunities for new technologies to be applied in improving vehicle safety, exploiting intelligent road infrastructure and enabling robotic vehicles operating in human environments.

The importance of thinking beyond the water-supply in cholera epidemics: A historical urban case-study.

PubMed

Phelps, Matthew D; Azman, Andrew S; Lewnard, Joseph A; Antillón, Marina; Simonsen, Lone; Andreasen, Viggo; Jensen, Peter K M; Pitzer, Virginia E

2017-11-01

Planning interventions to respond to cholera epidemics requires an understanding of the major transmission routes. Interrupting short-cycle (household, foodborne) transmission may require different approaches as compared long-cycle (environmentally-mediated/waterborne) transmission. However, differentiating the relative contribution of short- and long-cycle routes has remained difficult, and most cholera outbreak control efforts focus on interrupting long-cycle transmission. Here we use high-resolution epidemiological and municipal infrastructure data from a cholera outbreak in 1853 Copenhagen to explore the relative contribution of short- and long-cycle transmission routes during a major urban epidemic. We fit a spatially explicit time-series meta-population model to 6,552 physician-reported cholera cases from Copenhagen in 1853. We estimated the contribution of long-cycle waterborne transmission between neighborhoods using historical municipal water infrastructure data, fitting the force of infection from hydraulic flow, then comparing model performance. We found the epidemic was characterized by considerable transmission heterogeneity. Some neighborhoods acted as localized transmission hotspots, while other neighborhoods were less affected or important in driving the epidemic. We found little evidence to support long-cycle transmission between hydrologically-connected neighborhoods. Collectively, these findings suggest short-cycle transmission was significant. Spatially targeted cholera interventions, such as reactive vaccination or sanitation/hygiene campaigns in hotspot neighborhoods, would likely have been more effective in this epidemic than control measures aimed at interrupting long-cycle transmission, such as improving municipal water quality. We recommend public health planners consider programs aimed at interrupting short-cycle transmission as essential tools in the cholera control arsenal.

The importance of thinking beyond the water-supply in cholera epidemics: A historical urban case-study

PubMed Central

Azman, Andrew S.; Lewnard, Joseph A.; Antillón, Marina; Simonsen, Lone; Andreasen, Viggo; Jensen, Peter K. M.; Pitzer, Virginia E.

2017-01-01

Background Planning interventions to respond to cholera epidemics requires an understanding of the major transmission routes. Interrupting short-cycle (household, foodborne) transmission may require different approaches as compared long-cycle (environmentally-mediated/waterborne) transmission. However, differentiating the relative contribution of short- and long-cycle routes has remained difficult, and most cholera outbreak control efforts focus on interrupting long-cycle transmission. Here we use high-resolution epidemiological and municipal infrastructure data from a cholera outbreak in 1853 Copenhagen to explore the relative contribution of short- and long-cycle transmission routes during a major urban epidemic. Methodology/Principal findings We fit a spatially explicit time-series meta-population model to 6,552 physician-reported cholera cases from Copenhagen in 1853. We estimated the contribution of long-cycle waterborne transmission between neighborhoods using historical municipal water infrastructure data, fitting the force of infection from hydraulic flow, then comparing model performance. We found the epidemic was characterized by considerable transmission heterogeneity. Some neighborhoods acted as localized transmission hotspots, while other neighborhoods were less affected or important in driving the epidemic. We found little evidence to support long-cycle transmission between hydrologically-connected neighborhoods. Collectively, these findings suggest short-cycle transmission was significant. Conclusions/Significance Spatially targeted cholera interventions, such as reactive vaccination or sanitation/hygiene campaigns in hotspot neighborhoods, would likely have been more effective in this epidemic than control measures aimed at interrupting long-cycle transmission, such as improving municipal water quality. We recommend public health planners consider programs aimed at interrupting short-cycle transmission as essential tools in the cholera control arsenal. PMID:29176791

Effect of regional grid mix, driving patterns and climate on the comparative carbon footprint of gasoline and plug-in electric vehicles in the United States

NASA Astrophysics Data System (ADS)

Yuksel, Tugce; Tamayao, Mili-Ann M.; Hendrickson, Chris; Azevedo, Inês M. L.; Michalek, Jeremy J.

2016-04-01

We compare life cycle greenhouse gas (GHG) emissions from several light-duty passenger gasoline and plug-in electric vehicles (PEVs) across US counties by accounting for regional differences due to marginal grid mix, ambient temperature, patterns of vehicle miles traveled (VMT), and driving conditions (city versus highway). We find that PEVs can have larger or smaller carbon footprints than gasoline vehicles, depending on these regional factors and the specific vehicle models being compared. The Nissan Leaf battery electric vehicle has a smaller carbon footprint than the most efficient gasoline vehicle (the Toyota Prius) in the urban counties of California, Texas and Florida, whereas the Prius has a smaller carbon footprint in the Midwest and the South. The Leaf is lower emitting than the Mazda 3 conventional gasoline vehicle in most urban counties, but the Mazda 3 is lower emitting in rural Midwest counties. The Chevrolet Volt plug-in hybrid electric vehicle has a larger carbon footprint than the Prius throughout the continental US, though the Volt has a smaller carbon footprint than the Mazda 3 in many urban counties. Regional grid mix, temperature, driving conditions, and vehicle model all have substantial implications for identifying which technology has the lowest carbon footprint, whereas regional patterns of VMT have a much smaller effect. Given the variation in relative GHG implications, it is unlikely that blunt policy instruments that favor specific technology categories can ensure emission reductions universally.

THE EMERGENCE OF ARTHROPOD-BORNE VIRAL DISEASES: A GLOBAL PROSPECTIVE ON DENGUE, CHIKUNGUNYA AND ZIKA FEVERS

PubMed Central

Mayer, Sandra V.; Tesh, Robert B.; Vasilakis, Nikos

2016-01-01

Arthropod-borne viruses (arboviruses) present a substantial threat to human and animal health worldwide. Arboviruses can cause a variety of clinical presentations that range from mild to life threatening symptoms. Many arboviruses are present in nature through two distinct cycles, the urban and sylvatic cycle that are maintained in complex biological cycles. In this review we briefly discuss the factors driving the emergence of arboviruses, such as the anthropogenic aspects of unrestrained human population growth, economic expansion and globalization. Also the important aspects of viruses and vectors in the occurrence of arboviruses epidemics. The focus of this review will be on dengue, zika and chikungunya viruses, particularly because these viruses are currently causing a negative impact on public health and economic damage around the world. PMID:27876643

Differences between emissions measured in urban driving and certification testing of heavy-duty diesel engines

NASA Astrophysics Data System (ADS)

Dixit, Poornima; Miller, J. Wayne; Cocker, David R.; Oshinuga, Adewale; Jiang, Yu; Durbin, Thomas D.; Johnson, Kent C.

2017-10-01

Emissions from eight heavy-duty diesel trucks (HDDTs) equipped with three different exhaust aftertreatment systems (ATS) for controlling nitrogen oxide (NOx) emissions were quantified on a chassis dynamometer using driving schedules representative of stop-and-go and free-flow driving in metropolitan areas. The three control technologies were: 1) cooled exhaust gas recirculation (CEGR) plus a diesel particulate filter (DPF); 2) CEGR and DPF plus advanced engine controls; and 3) CEGR and DPF plus selective catalytic reduction with ammonia (SCR). Results for all control technologies and driving conditions showed PM emission factors were less than the standard, while selected non-regulated emissions (ammonia, carbonyls, and C4-C12 hydrocarbons) and a greenhouse gas (nitrous oxide) were at measurement detection limits. However, NOx emission factors depended on the control technology, engine calibration, and driving mode. For example, emissions from engines with cooled-exhaust gas recirculation (CEGR) were 239% higher for stop-and-go driving as compared with free-flow. For CEGR plus selective catalytic reduction (SCR), the ratio was 450%. A deeper analysis was carried out with the assumption that emissions measured for a drive cycle on either the chassis or in-use driving would be similar. Applying the same NTE rules to the chassis data showed emissions during stop-and-go driving often exceeded the certification standard and >90% of the driving did not fall within the Not-To-Exceed (NTE) control area suggesting the NTE requirements do not provide sufficient emissions control under in-use conditions. On-road measurement of emissions using the same mobile lab while the vehicle followed a free-flow driving schedule verified the chassis results. These results have implications for scientists who build inventories using certification values instead of real world emission values and for metropolitan populations, who are exposed to elevated emissions. The differences in values between real world emissions and certification cycles should be narrowed. For example, one might use a different mix of cold and hot start testing to greater emphasize low temperature/load operation, a separate cycle to specifically characterize low-load operation, or broaden the in-use compliance testing requirements and associated conformity factors to incorporate a wider envelope of vehicle operation, especially at low load conditions. .

Velocity-dependent emission factors of benzene, toluene and C 2-benzenes of a passenger car equipped with and without a regulated 3-way catalyst

NASA Astrophysics Data System (ADS)

Heeb, Norbert V.; Forss, Anna-Maria; Bach, Christian; Mattrel, Peter

Time-resolved chemical ionization mass spectrometry (CI-MS) has been used to investigate the velocity-dependent emission factors for benzene, toluene, the C 2-benzenes (xylenes and ethyl benzene) and nitrogen monoxide of a gasoline-driven passenger car (1.4 l, model year 1995) driven with or without catalytic exhaust gas treatment. A set of seven different driving cycles - including the European Driving Cycle (EDC), the US Urban (FTP 75) and the Highway driving cycles - with a total driving time of 12,000 s have been studied. From the obtained emission data, two sets of 15,300 and 17,200 data points which represent transient driving in the velocity range of 0-150 km h -1 and in an acceleration window of -2-3 m s -2 were explored to gain velocity-dependent emission factors. The passenger car, equipped with a regulated rhodium-platinum based three-way catalyst, showed optimal conversion efficiency (>95%) for benzene in the velocity range of 60-120 km h -1. The conversion of benzene was reduced (<80%) when driving below 50 km h -1 and the BTXE emissions significantly increased when driven at higher speed and engine load (>130 km h -1). Whereas the conversion efficiency for the class of C 2-benzenes was reduced to 10%, no net conversion could be found for toluene and benzene when driven above 130 km h -1. In contrast, the benzene and toluene emissions exceeded those of the untreated exhaust gas in the velocity range of 130-150 km h -1 by 50-92% and by 10-34%, respectively. Thus, benzene and toluene were formed across the examined three-way catalyst if the engine is operated for an extended time in a fuel-rich mode (lambda<1).

40 CFR 86.1215-85 - EPA heavy-duty vehicle (HDV) urban dynamometer driving schedule.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false EPA heavy-duty vehicle (HDV) urban..., Liquefied Petroleum Gas-Fueled and Methanol-Fueled Heavy-Duty Vehicles § 86.1215-85 EPA heavy-duty vehicle (HDV) urban dynamometer driving schedule. (a)(1) The EPA dynamometer driving schedule for heavy-duty...

40 CFR 600.109-78 - EPA driving cycles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false EPA driving cycles. 600.109-78 Section... Model Year Automobiles-Test Procedures § 600.109-78 EPA driving cycles. (a) The driving cycle to be... driving cycle to be utilized for generation of the highway fuel economy data is specified in this...

Flywheel/Diesel Hybrid Power Drive: Urban Bus Vehicle Simulation.

DOT National Transportation Integrated Search

1978-05-01

This report describes the results of a Transportation Systems Center investigation conducted under Urban Mass Transportation Administration sponsorship, of the practicality of a flywheel/diesel hybrid power drive for urban transit bus propulsion. The...

40 CFR 600.109-08 - EPA driving cycles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false EPA driving cycles. 600.109-08 Section... Model Year Automobiles-Test Procedures § 600.109-08 EPA driving cycles. (a) The FTP driving cycle is prescribed in § 86.115 of this chapter. (b) The highway fuel economy driving cycle is specified in this...

NOx emissions from Euro IV busses with SCR systems associated with urban, suburban and freeway driving patterns.

PubMed

Fu, Mingliang; Ge, Yunshan; Wang, Xin; Tan, Jianwei; Yu, Linxiao; Liang, Bin

2013-05-01

NOx and particulate matter (PM) emissions from heavy-duty diesel vehicles (HDVs) have become the most important sources of pollutants affecting urban air quality in China. In recent years, a series of emission control strategies and diesel engine polices have been introduced that require advanced emission control technology. China and Europe mostly have used Selective Catalytic Reduction (SCR) with urea to meet the Euro IV diesel engine emission standard. In this study, two Euro IV busses with SCR were tested by using potable emission measurement system (PEMS) to assess NOx emissions associated with urban, suburban and freeway driving patterns. The results indicated that with the SCR system, the urea injection time for the entire driving period increased with higher vehicle speed. For freeway driving, the urea injection time covered 71%-83% of the driving period; the NOx emission factors from freeway driving were lower than those associated with urban and suburban driving. Unfortunately, the NOx emission factors were 2.6-2.8-, 2.3-2.7- and 2.2-2.3-fold higher than the Euro IV standard limits for urban, suburban and freeway driving, respectively; NOx emission factors (in g/km and g/(kW·h)) from the original vehicles (without SCR) were higher than their corresponding vehicles with SCR for suburban and freeway driving. Compared with the IVE model results, the measured NOx emission factors were 1.60-1.16-, 1.77-1.27-, 2.49-2.44-fold higher than the NOx predicted by the IVE model for urban and suburban driving, respectively. Thus, an adjustment of emission factors is needed to improve the estimation of Euro IV vehicle emissions in China. Copyright © 2013 Elsevier B.V. All rights reserved.

Safety evaluation model of urban cross-river tunnel based on driving simulation.

PubMed

Ma, Yingqi; Lu, Linjun; Lu, Jian John

2017-09-01

Currently, Shanghai urban cross-river tunnels have three principal characteristics: increased traffic, a high accident rate and rapidly developing construction. Because of their complex geographic and hydrological characteristics, the alignment conditions in urban cross-river tunnels are more complicated than in highway tunnels, so a safety evaluation of urban cross-river tunnels is necessary to suggest follow-up construction and changes in operational management. A driving risk index (DRI) for urban cross-river tunnels was proposed in this study. An index system was also constructed, combining eight factors derived from the output of a driving simulator regarding three aspects of risk due to following, lateral accidents and driver workload. Analytic hierarchy process methods and expert marking and normalization processing were applied to construct a mathematical model for the DRI. The driving simulator was used to simulate 12 Shanghai urban cross-river tunnels and a relationship was obtained between the DRI for the tunnels and the corresponding accident rate (AR) via a regression analysis. The regression analysis results showed that the relationship between the DRI and the AR mapped to an exponential function with a high degree of fit. In the absence of detailed accident data, a safety evaluation model based on factors derived from a driving simulation can effectively assess the driving risk in urban cross-river tunnels constructed or in design.

Characterisation of an urban bus network for environmental purposes.

PubMed

André, Michel; Villanova, André

2004-12-01

Since pollutant emissions are closely related to the operating conditions of vehicles, their evaluation usually involves studying these operating conditions (through bus instrumentation and monitoring under actual operation), the design of representative driving or engine test cycles and the measurement of pollutant emissions. A preliminary characterisation of the routes on a bus network should make it possible to identify typical routes, the driving conditions and pollutant emissions of which are then studied. Two approaches are envisaged and applied to the Paris area, for which a wealth of information is available, which should be transferable to other bus networks. Both approaches are based on factorial analysis and automatic clustering, to allow optimum description and the identification of a pertinent typology of the bus routes in several classes. The first attempt at characterisation is based on statistics relating to bus operations: route characteristics (length, dedicated bus lanes, number of stops, location of stops: schools, tourist sites, hospitals, railways or underground stations), travel time, commercial speed, annual statistics (number of passengers, number of vehicles per hour, total kilometres), the irregularity of travel (variation of travel times, injuries, congestion.), as well as information on the problems encountered (congestion, distribution of the passenger load, junctions, bends). A second approach is based on the analysis of the "urban context" in which buses are driven. Population, employment, housing, road network, traffic and places that generate or disturb traffic (schools, railway stations, shopping areas, etc.) are calculated for the Ile de France region, by cells of 100 x 100 m, and collected in a geographical information system (GIS). Statistical analyses enable a typology of these urban cells to be established, the main parameters being density, type of housing, road types and traffic levels. The bus routes are then analysed according to their itineraries across these typical areas (distances travelled in each type of area) using a similar approach. A comparison of the typologies obtained from operational data and from urban data highlights the advantages and disadvantages of the two approaches. The first result from these typologies is the selection of routes which are representative of the different classes, in order to instrument buses and record driving patterns. This method should also make it possible to link driving conditions and urban characteristics, and then to allocate pollutant emission factors to given geographical situations, in particular, in the context of emission inventories or impact studies.

New research assessing the effect of engine operating conditions on regulated emissions of a 4-stroke motorcycle by test bench measurements

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

Iodice, Paolo, E-mail: paolo.iodice@unina.it; Senatore, Adolfo

In the latest years the effect of powered two-wheelers on air polluting emissions is generally noteworthy all over the world, notwithstanding advances in internal combustion engines allowed to reduce considerably both fuel consumption and exhaust emissions of SI engines. Nowadays, in fact, these vehicles represent common means of quotidian moving, serving to meet daily urban transport necessities with a significant environmental impact on air quality. Besides, the emissive behavior of the two-wheelers measured under fixed legislative driving standards (and not on the local driving conditions) might not be sufficiently representative of real world motorcycle riding. The purpose of this investigationmore » is a deeper research on emissive levels of in-use motorcycles equipped with last generation SI engines under real world driving behavior. In order to analyze the effect of vehicle instantaneous speed and acceleration on emissive behavior, instantaneous emissions of CO, HC and NO{sub X} were measured in the exhaust of a four-stroke motorcycle, equipped with a three-way catalyst and belonging to the Euro-3 legislative category. Experimental tests were executed on a chassis dynamometer bench in the laboratories of the National Research Council (Italy), during the Type Approval test cycle, at constant speed and under real-world driving cycles. This analytical-experimental investigation was executed with a methodology that improves vehicles emission assessment in comparison with the modeling approaches that are based on fixed legislative driving standards. The statistical processing results so obtained are very useful also in order to improve the database of emission models commonly used for estimating emissions from road transport sector, then they can be used to evaluate the environmental impact of last generation medium-size motorcycles under real driving behaviors.« less

Naturalistic drive cycle synthesis for pickup trucks.

PubMed

Liu, Zifan; Ivanco, Andrej; Filipi, Zoran

2015-09-01

Future pick-up trucks are meeting much stricter fuel economy and exhaust emission standards. Design tradeoffs will have to be carefully evaluated to satisfy consumer expectations within the regulatory and cost constraints. Boundary conditions will obviously be critical for decision making: thus, the understanding of how customers are driving in naturalistic settings is indispensable. Federal driving schedules, while critical for certification, do not capture the richness of naturalistic cycles, particularly the aggressive maneuvers that often shape consumer perception of performance. While there are databases with large number of drive cycles, applying all of them directly in the design process is impractical. Therefore, representative drive cycles that capture the essence of the naturalistic driving should be synthesized from naturalistic driving data. Naturalistic drive cycles are firstly categorized by investigating their micro-trip components, defined as driving activities between successive stops. Micro-trips are expected to characterize underlying local traffic conditions, and separate different driving patterns. Next, the transitions from one vehicle state to another vehicle state in each cycle category are captured with Transition Probability Matrix (TPM). Candidate drive cycles can subsequently be synthesized using Markov Chain based on TPMs for each category. Finally, representative synthetic drive cycles are selected through assessment of significant cycle metrics to identify the ones with smallest errors. This paper provides a framework for synthesis of representative drive cycles from naturalistic driving data, which can subsequently be used for efficient optimization of design or control of pick-up truck powertrains. Manufacturers will benefit from representative drive cycles in several aspects, including quick assessments of vehicle performance and energy consumption in simulations, component sizing and design, optimization of control strategies, and vehicle testing under real-world conditions. This is in contrast to using federal certification test cycles, which were never intended to capture pickup truck segment. Copyright © 2015 Elsevier Ltd and National Safety Council. All rights reserved.

Characteristics of black carbon emissions from in-use light-duty passenger vehicles.

PubMed

Zheng, Xuan; Zhang, Shaojun; Wu, Ye; Zhang, K Max; Wu, Xian; Li, Zhenhua; Hao, Jiming

2017-12-01

Mitigating black carbon (BC) emissions from various combustion sources has been considered an urgent policy issue to address the challenges of climate change, air pollution and health risks. Vehicles contribute considerably to total anthropogenic BC emissions and urban BC concentrations. Compared with heavy-duty diesel vehicles, there is much larger uncertainty in BC emission factors for light-duty passenger vehicles (LDPVs), in particular for gasoline LDPVs, which warrants further studies. In this study, we employed the dynamometer and the Aethalometer (AE-51) to measure second-by-second BC emissions from eight LDPVs by engine technology and driving cycle. The average BC emission factors under transient cycles (e.g., ECE-15, New European Driving Cycle, NEDC, Worldwide Harmonized Light Vehicles Test Cycle, WLTC) are 3.6-91.5 mg/km, 7.6 mg/km and 0.13-0.58 mg/km, respectively, for diesel (N = 3), gasoline direct injection (GDI) (N = 1) and gasoline port-fuel injection (PFI) engine categories (N = 4). For gasoline PFI LDPVs, the instantaneous emission profiles show a strong association of peak BC emissions with cold-start and high-speed aggressive driving. Such impacts lead to considerable BC emission contributions in cold-start periods (e.g., the first 47 s-94 s) over the entire cycle (e.g., 18-76% of the NEDC and 13-36% of the WLTC) and increased BC emission factors by 80-440% under the WLTC compared to the NEDC. For diesel BC emissions, the size distribution exhibits a typical unimodal pattern with one single peak appearing approximately from 120 to 150 nm, which is largely consistent with previous studies. Nevertheless, the average mass ratios of BC to particle mass (PM) range from 0.38 to 0.54 for three diesel samples, representing substantial impacts from both driving and engine conditions. The significant discrepancy between gasoline BC emission factors obtained from tailpipe exhaust versus ambient conditions suggest that more comparative measurements and fine-grained simulations should be designed and implemented to address this discrepancy. Copyright © 2017 Elsevier Ltd. All rights reserved.

COMPARATIVE STUDY ON EXHAUST EMISSIONS FROM DIESEL- AND CNG-POWERED URBAN BUSES

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

COROLLER, P; PLASSAT, G

2003-08-24

Couple years ago, ADEME engaged programs dedicated to the urban buses exhaust emissions studies. The measures associated with the reduction of atmospheric and noise pollution has particular importance in the sector of urban buses. In many cases, they illustrate the city's environmental image and contribute to reinforcing the attractiveness of public transport. France's fleet in service, presently put at about 14,000 units, consumes about 2 per cent of the total energy of city transport. It causes about 2 per cent of the HC emissions and from 4 to 6 per cent of the NOx emissions and particles. These vehicles typicallymore » have a long life span (about 15 years) and are relatively expensive to buy, about 150.000 euros per unit. Several technical solutions were evaluated to quantify, on a real condition cycle for buses, on one hand pollutants emissions, fuel consumption and on the other hand reliability, cost in real existing fleet. This paper presents main preliminary results on urban buses exhaust emission on two different cases: - existing Diesel buses, with fuel modifications (Diesel with low sulphur content), Diesel with water emulsion and bio-Diesel (30% oil ester in standard Diesel fuel); renovating CNG powered Euro II buses fleet, over representative driving cycles, set up by ADEME and partners. On these cycles, pollutants (regulated and unregulated) were measured as well as fuel consumption, at the beginning of a program and one year after to quantify reliability and increase/decrease of pollutants emissions. At the same time, some after-treatment technologies were tested under real conditions and several vehicles. Information such as fuel consumption, lubricant analysis, problem on the technology were following during a one year program. On the overall level, it is the combination of various action, pollution-reduction and renewal that will make it possible to meet the technological challenge of reducing emissions and fuel consumption by urban bus networks.« less

40 CFR Appendix E to Subpart S of... - Transient Test Driving Cycle

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 2 2010-07-01 2010-07-01 false Transient Test Driving Cycle E Appendix... Driving Cycle (I) Driver's trace. All excursions in the transient driving cycle shall be evaluated by the... shall cause a test to be void. In addition, provisions shall be available to utilize cycle validation...

40 CFR 86.215-94 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 18 2011-07-01 2011-07-01 false EPA urban dynamometer driving schedule. 86.215-94 Section 86.215-94 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.215-94 EPA urban dynamometer...

Size-resolved particle number emission patterns under real-world driving conditions using positive matrix factorization.

PubMed

Domínguez-Sáez, Aida; Viana, Mar; Barrios, Carmen C; Rubio, Jose R; Amato, Fulvio; Pujadas, Manuel; Querol, Xavier

2012-10-16

A novel on-board system was tested to characterize size-resolved particle number emission patterns under real-world driving conditions, running in a EURO4 diesel vehicle and in a typical urban circuit in Madrid (Spain). Emission profiles were determined as a function of driving conditions. Source apportionment by Positive Matrix Factorization (PMF) was carried out to interpret the real-world driving conditions. Three emission patterns were identified: (F1) cruise conditions, with medium-high speeds, contributing in this circuit with 60% of total particle number and a particle size distribution dominated by particles >52 nm and around 60 nm; (F2) transient conditions, stop-and-go conditions at medium-high speed, contributing with 25% of the particle number and mainly emitting particles in the nucleation mode; and (F3) creep-idle conditions, representing traffic congestion and frequent idling periods, contributing with 14% to the total particle number and with particles in the nucleation mode (<29.4 nm) and around 98 nm. We suggest potential approaches to reduce particle number emissions depending on particle size and driving conditions. Differences between real-world emission patterns and regulatory cycles (NEDC) are also presented, which evidence that detecting particle number emissions <40 nm is only possible under real-world driving conditions.

A Healthy Reduction in Oil Dependence and Carbon Emissions

NASA Astrophysics Data System (ADS)

Higgins, P. A.; Higgins, M.

2003-12-01

Societal dependence on oil as an energy source for personal transportation leads to increasingly negative social consequences including climate change, air pollution, political and economic instability and habitat degradation. Our heavy reliance on the automobile for transportation, determined in part by urban sprawl, also contributes to the population's increasingly sedentary lifestyle and to a concomitant degradation in health. We have shown that widespread substitution of exercise, commensurate with previously recommended levels, through biking or walking instead of driving can substantially reduce oil consumption and carbon emissions. For example, if all individuals between the ages of 10 and 64 substituted one hour of cycling for driving the reduction in gasoline demand would be equivalent to the gas produced from 34.9 percent of current oil consumption. Relative to 1990 net US emissions, this constitutes a 10.9 percent reduction in carbon emissions. Therefore, substitution of exercise for driving could improve health, reduce carbon emissions and save more oil than even upper estimates of that contained in the Arctic National Wildlife Refuge.

Drive Cycle Data | Transportation Secure Data Center | NREL

Science.gov Websites

one file. Download Individual Survey and Study Drive Cycle Data Below you'll find drive cycle data download files for individual surveys and studies. Greater Fairbanks, Alaska, Transportation Survey Drive Cycle Data by Vehicle (24-hour period of operation) Download Learn more about the survey. California

Effects of vehicle type and fuel quality on real world toxic emissions from diesel vehicles

NASA Astrophysics Data System (ADS)

Nelson, Peter F.; Tibbett, Anne R.; Day, Stuart J.

Diesel vehicles are an important source of emissions of air pollutants, particularly oxides of nitrogen (NO x), particulate matter (PM), and toxic compounds with potential health impacts including volatile organic compounds (VOCs) such as benzene and aldehydes, and polycyclic aromatic hydrocarbons (PAHs). Current developments in engine design and fuel quality are expected to reduce these emissions in the future, but many vehicles exceed 10 years of age and may make a major contribution to urban pollutant concentrations and related health impacts for many years. In this study, emissions of a range of toxic compounds are reported using in-service vehicles which were tested using urban driving cycles developed for Australian conditions. Twelve vehicles were chosen from six vehicle weight classes and, in addition, two of these vehicles were driven through the urban drive cycle using a range of diesel fuel formulations. The fuels ranged in sulphur content from 24 to 1700 ppm, and in total aromatics from 7.7 to 33 mass%. Effects of vehicle type and fuel composition on emissions are reported. The results show that emissions of these toxic species were broadly comparable to those observed in previous dynamometer and tunnel studies. Emissions of VOCs and smaller PAHs such as naphthalene, which are derived largely from the combustion process, appear to be related, and show relatively little variability when compared with the variability in emissions of aldehydes and larger PAHs. In particular, aldehyde emissions are highly variable and may be related to engine operating conditions. Fuels of lower sulphur and aromatic content did not have a significant influence on emissions of VOCs and aldehydes, but tended to result in lower emissions of PAHs. The toxicity of vehicle exhaust, as determined by inhalation risk and toxic equivalency factor (TEF)-weighted PAH emissions, was reduced with fuels of lower aromatic content.

Simulated Fuel Economy and Emissions Performance during City and Interstate Driving for a Heavy-Duty Hybrid Truck

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

Daw, C. Stuart; Gao, Zhiming; Smith, David E.

2013-04-08

We compare simulated fuel economy and emissions for both conventional and hybrid class 8 heavy-duty diesel trucks operating over multiple urban and highway driving cycles. Both light and heavy freight loads were considered, and all simulations included full aftertreatment for NOx and particulate emissions controls. The aftertreatment components included a diesel oxidation catalyst (DOC), urea-selective catalytic NOx reduction (SCR), and a catalyzed diesel particulate filter (DPF). Our simulated hybrid powertrain was configured with a pre-transmission parallel drive, with a single electric motor between the clutch and gearbox. A conventional HD truck with equivalent diesel engine and aftertreatment was also simulatedmore » for comparison. Our results indicate that hybridization can significantly increase HD fuel economy and improve emissions control in city driving. However, there is less potential hybridization benefit for HD highway driving. A major factor behind the reduced hybridization benefit for highway driving is that there are fewer opportunities to utilize regenerative breaking. Our aftertreatment simulations indicate that opportunities for passive DPF regeneration are much greater for both hybrid and conventional trucks during highway driving due to higher sustained exhaust temperatures. When passive DPF regeneration is extensively utilized, the fuel penalty for particulate control is virtually eliminated, except for the 0.4%-0.9% fuel penalty associated with the slightly higher exhaust backpressure.« less

Electric Vehicles Mileage Extender Kinetic Energy Storage

NASA Astrophysics Data System (ADS)

Jivkov, Venelin; Draganov, Vutko; Stoyanova, Yana

2015-03-01

The proposed paper considers small urban vehicles with electric hybrid propulsion systems. Energy demands are examined on the basis of European drive cycle (NEUDC) and on an energy recuperation coefficient and are formulated for description of cycle energy transfers. Numerical simulation results show real possibilities for increasing in achievable vehicle mileage at the same energy levels of a main energy source - the electric battery. Kinetic energy storage (KES), as proposed to be used as an energy buffer and different structural schemes of the hybrid propulsion system are commented. Minimum energy levels for primary (the electric battery) and secondary (KES) sources are evaluated. A strategy for reduced power flows control is examined, and its impact on achievable vehicle mileage is investigated. Results show an additional increase in simulated mileage at the same initial energy levels.

Influence of driving cycles on exhaust emissions and fuel consumption of gasoline passenger car in Bangkok.

PubMed

Nutramon, Tamsanya; Supachart, Chungpaibulpatana

2009-01-01

The influence of different driving cycles on their exhaust emissions and fuel consumption rate of gasoline passenger car was investigated in Bangkok based on the actual measurements obtained from a test vehicle driving on a standard chassis dynamometer. A newly established Bangkok driving cycle (BDC) and the European driving cycle (EDC) which is presently adopted as the legislative cycle for testing automobiles registered in Thailand were used. The newly developed BDC is constructed using the driving characteristic data obtained from the real on-road driving tests along selected traffic routes. A method for selecting appropriate road routes for real driving tests is also introduced. Variations of keyed driving parameters of BDC with different driving cycles were discussed. The results showed that the HC and CO emission factors of BDC are almost two and four times greater than those of EDC, respectively. Although the difference in the NOx emission factor is small, the value from BDC is still greater than that of EDC by 10%. Under BDC, the test vehicle consumes fuel about 25% more than it does under EDC. All these differences are mainly attributed to the greater proportion of idle periods and higher fluctuations of vehicle speed in the BDC cycle. This result indicated that the exhausted emissions and fuel consumption of vehicles obtained from tests under the legislative modal-type driving cycle (EDC) are significantly different from those actually produced under real traffic conditions especially during peak periods.

Development of a Short-Duration Drive Cycle to Represent Long-Term Measured Drive Cycle Data: Evaluation of Truck Efficiency Technologies in Class 8 Tractor Trailers

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

LaClair, Tim; Gao, Zhiming; Fu, Joshua

Quantifying the fuel savings and emissions reductions that can be achieved from truck fuel efficiency technologies for a fleet's specific usage allows the fleet to select a combination of technologies that will yield the greatest operational efficiency and profitability. An accurate characterization of usage for the fleet is critical for such an evaluation; however, short-term measured drive cycle data do not generally reflect overall usage very effectively. This study presents a detailed analysis of vehicle usage in a commercial vehicle fleet and demonstrates the development of a short-duration synthetic drive cycle with measured drive cycle data collected over an extendedmore » period of time. The approach matched statistical measures of the vehicle speed with acceleration history and integrated measured grade data to develop a compressed drive cycle that accurately represents total usage. Drive cycle measurements obtained during a full year from six tractor trailers in normal operations in a less-than-truckload carrier were analyzed to develop a synthetic drive cycle. The vehicle mass was also estimated to account for the variation of loads that the fleet experienced. These drive cycle and mass data were analyzed with a tractive energy analysis to quantify the benefits in terms of fuel efficiency and reduced carbon dioxide emissions that can be achieved on Class 8 tractor trailers by using advanced efficiency technologies, either individually or in combination. Although differences exist between Class 8 tractor trailer fleets, this study provides valuable insight into the energy and emissions reduction potential that various technologies can bring in this important trucking application. Finally, the methodology employed for generating the synthetic drive cycle serves as a rigorous approach to develop an accurate usage characterization that can be used to effectively compress large quantities of drive cycle data.« less

Development of a Short-Duration Drive Cycle to Represent Long-Term Measured Drive Cycle Data: Evaluation of Truck Efficiency Technologies in Class 8 Tractor Trailers

DOE PAGES

LaClair, Tim; Gao, Zhiming; Fu, Joshua; ...

2014-12-01

Quantifying the fuel savings and emissions reductions that can be achieved from truck fuel efficiency technologies for a fleet's specific usage allows the fleet to select a combination of technologies that will yield the greatest operational efficiency and profitability. An accurate characterization of usage for the fleet is critical for such an evaluation; however, short-term measured drive cycle data do not generally reflect overall usage very effectively. This study presents a detailed analysis of vehicle usage in a commercial vehicle fleet and demonstrates the development of a short-duration synthetic drive cycle with measured drive cycle data collected over an extendedmore » period of time. The approach matched statistical measures of the vehicle speed with acceleration history and integrated measured grade data to develop a compressed drive cycle that accurately represents total usage. Drive cycle measurements obtained during a full year from six tractor trailers in normal operations in a less-than-truckload carrier were analyzed to develop a synthetic drive cycle. The vehicle mass was also estimated to account for the variation of loads that the fleet experienced. These drive cycle and mass data were analyzed with a tractive energy analysis to quantify the benefits in terms of fuel efficiency and reduced carbon dioxide emissions that can be achieved on Class 8 tractor trailers by using advanced efficiency technologies, either individually or in combination. Although differences exist between Class 8 tractor trailer fleets, this study provides valuable insight into the energy and emissions reduction potential that various technologies can bring in this important trucking application. Finally, the methodology employed for generating the synthetic drive cycle serves as a rigorous approach to develop an accurate usage characterization that can be used to effectively compress large quantities of drive cycle data.« less

Changing and Differentiated Urban Landscape in China: Spatiotemporal Patterns and Driving Forces.

PubMed

Fang, Chuanglin; Li, Guangdong; Wang, Shaojian

2016-03-01

Urban landscape spatiotemporal change patterns and their driving mechanisms in China are poorly understood at the national level. Here we used remote sensing data, landscape metrics, and a spatial econometric model to characterize the spatiotemporal patterns of urban landscape change and investigate its driving forces in China between 1990 and 2005. The results showed that the urban landscape pattern has experienced drastic changes over the past 15 years. Total urban area has expanded approximately 1.61 times, with a 2.98% annual urban-growth rate. Compared to previous single-city studies, although urban areas are expanding rapidly, the overall fragmentation of the urban landscape is decreasing and is more irregular and complex at the national level. We also found a stair-stepping, urban-landscape changing pattern among eastern, central, and western counties. In addition, administrative level, urban size, and hierarchy have effects on the urban landscape pattern. We also found that a combination of landscape metrics can be used to supplement our understanding of the pattern of urbanization. The changes in these metrics are correlated with geographical indicators, socioeconomic factors, infrastructure variables, administrative level factors, policy factors, and historical factors. Our results indicate that the top priority should be strengthening the management of urban planning. A compact and congregate urban landscape may be a good choice of pattern for urban development in China.

Emissions of toxic pollutants from compressed natural gas and low sulfur diesel-fueled heavy-duty transit buses tested over multiple driving cycles.

PubMed

Kado, Norman Y; Okamoto, Robert A; Kuzmicky, Paul A; Kobayashi, Reiko; Ayala, Alberto; Gebel, Michael E; Rieger, Paul L; Maddox, Christine; Zafonte, Leo

2005-10-01

The number of heavy-duty vehicles using alternative fuels such as compressed natural gas (CNG) and new low-sulfur diesel fuel formulations and equipped with after-treatment devices are projected to increase. However, few peer-reviewed studies have characterized the emissions of particulate matter (PM) and other toxic compounds from these vehicles. In this study, chemical and biological analyses were used to characterize the identifiable toxic air pollutants emitted from both CNG and low-sulfur-diesel-fueled heavy-duty transit buses tested on a chassis dynamometer over three transient driving cycles and a steady-state cruise condition. The CNG bus had no after-treatment, and the diesel bus was tested first equipped with an oxidation catalyst (OC) and then with a catalyzed diesel particulate filter (DPF). Emissions were analyzed for PM, volatile organic compounds (VOCs; determined on-site), polycyclic aromatic hydrocarbons (PAHs), and mutagenic activity. The 2000 model year CNG-fueled vehicle had the highest emissions of 1,3-butadiene, benzene, and carbonyls (e.g., formaldehyde) of the three vehicle configurations tested in this study. The 1998 model year diesel bus equipped with an OC and fueled with low-sulfur diesel had the highest emission rates of PM and PAHs. The highest specific mutagenic activities (revertants/microg PM, or potency) and the highest mutagen emission rates (revertants/mi) were from the CNG bus in strain TA98 tested over the New York Bus (NYB) driving cycle. The 1998 model year diesel bus with DPF had the lowest VOCs, PAH, and mutagenic activity emission. In general, the NYB driving cycle had the highest emission rates (g/mi), and the Urban Dynamometer Driving Schedule (UDDS) had the lowest emission rates for all toxics tested over the three transient test cycles investigated. Also, transient emissions were, in general, higher than steady-state emissions. The emissions of toxic compounds from an in-use CNG transit bus (without an oxidation catalyst) and from a vehicle fueled with low-sulfur diesel fuel (equipped with DPF) were lower than from the low-sulfur diesel fueled vehicle equipped with OC. All vehicle configurations had generally lower emissions of toxics than an uncontrolled diesel engine. Tunnel backgrounds (measurements without the vehicle running) were measured throughout this study and were helpful in determining the incremental increase in pollutant emissions. Also, the on-site determination of VOCs, especially 1,3-butadiene, helped minimize measurement losses due to sample degradation after collection.

Development and Testing of an UltraBattery-Equipped Honda Civic Hybrid

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

Sally; Tyler Gray; Pattie Hovorka

2012-08-01

The UltraBattery Retrofit Project DP1.8 and Carbon Enriched Project C3, performed by ECOtality North America (ECOtality) and funded by the U.S. Department of Energy and the Advanced Lead Acid Battery Consortium (ALABC), are established to demonstrate the suitability of advanced lead battery technology in hybrid electrical vehicles (HEVs). A profile, termed the “Simulated Honda Civic HEV Profile” (SHCHEVP) has been developed in Project DP1.8 in order to provide reproducible laboratory evaluations of different battery types under real-world HEV conditions. The cycle is based on the Urban Dynamometer Driving Schedule and Highway Fuel Economy Test cycles and simulates operation of amore » battery pack in a Honda Civic HEV. One pass through the SHCHEVP takes 2,140 seconds and simulates 17.7 miles of driving. A complete nickel metal hydride (NiMH) battery pack was removed from a Honda Civic HEV and operated under SHCHEVP to validate the profile. The voltage behavior and energy balance of the battery during this operation was virtually the same as that displayed by the battery when in the Honda Civic operating on the dynamometer under the Urban Dynamometer Driving Schedule and Highway Fuel Economy Test cycles, thus confirming the efficacy of the simulated profile. An important objective of the project has been to benchmark the performance of the UltraBatteries manufactured by both Furukawa Battery Co., Ltd., Japan (Furakawa) and East Penn Manufacturing Co., Inc. (East Penn). Accordingly, UltraBattery packs from both Furakawa and East Penn have been characterized under a range of conditions. Resistance measurements and capacity tests at various rates show that both battery types are very similar in performance. Both technologies, as well as a standard lead-acid module (included for baseline data), were evaluated under a simple HEV screening test. Both Furakawa and East Penn UltraBattery packs operated for over 32,000 HEV cycles, with minimal loss in performance; whereas the standard lead-acid unit experienced significant degradation after only 6,273 cycles. The high-carbon, ALABC battery manufactured in Project C3 also was tested under the advanced HEV schedule. Its performance was significantly better than the standard lead-acid unit, but was still inferior compared with the UltraBattery. The batteries supplied by Exide as part of the C3 Project performed well under the HEV screening test, especially at high temperatures. The results suggest that higher operating temperatures may improve the performance of lead-acid-based technologies operated under HEV conditions—it is recommended that life studies be conducted on these technologies under such conditions.« less

Temperature effects on particulate emissions from DPF-equipped diesel trucks operating on conventional and biodiesel fuels.

PubMed

Book, Emily K; Snow, Richard; Long, Thomas; Fang, Tiegang; Baldauf, Richard

2015-06-01

Emissions tests were conducted on two medium heavy-duty diesel trucks equipped with a particulate filter (DPF), with one vehicle using a NOx absorber and the other a selective catalytic reduction (SCR) system for control of nitrogen oxides (NOx). Both vehicles were tested with two different fuels (ultra-low-sulfur diesel [ULSD] and biodiesel [B20]) and ambient temperatures (70ºF and 20ºF), while the truck with the NOx absorber was also operated at two loads (a heavy weight and a light weight). The test procedure included three driving cycles, a cold start with low transients (CSLT), the federal heavy-duty urban dynamometer driving schedule (UDDS), and a warm start with low transients (WSLT). Particulate matter (PM) emissions were measured second-by-second using an Aethalometer for black carbon (BC) concentrations and an engine exhaust particle sizer (EEPS) for particle count measurements between 5.6 and 560 nm. The DPF/NOx absorber vehicle experienced increased BC and particle number concentrations during cold starts under cold ambient conditions, with concentrations two to three times higher than under warm starts at higher ambient temperatures. The average particle count for the UDDS showed an opposite trend, with an approximately 27% decrease when ambient temperatures decreased from 70ºF to 20ºF. This vehicle experienced decreased emissions when going from ULSD to B20. The DPF/SCR vehicle tested had much lower emissions, with many of the BC and particle number measurements below detectable limits. However, both vehicles did experience elevated emissions caused by DPF regeneration. All regeneration events occurred during the UDDS cycle. Slight increases in emissions were measured during the WSLT cycles after the regeneration. However, the day after a regeneration occurred, both vehicles showed significant increases in particle number and BC for the CSLT drive cycle, with increases from 93 to 1380% for PM number emissions compared with tests following a day with no regeneration. The use of diesel particulate filters (DPFs) on trucks is becoming more common throughout the world. Understanding how DPFs affect air pollution emissions under varying operating conditions will be critical in implementing effective air quality standards. This study evaluated particulate matter (PM) and black carbon (BC) emissions with two DPF-equipped heavy-duty diesel trucks operating on conventional fuel and a biodiesel fuel blend at varying ambient temperatures, loads, and drive cycles.

Systems Engineering Methodology for Fuel Efficiency and its Application to the TARDEC Fuel Efficient Demonstrator (FED) Program

DTIC Science & Technology

2010-08-19

highlight the benefits of regenerative braking . Parameters within the drive cycle may include vehicle speed, elevation/grade changes, road surface...assist to downsize the engine due to infinite maximum speed requirements • Drive cycle less suited to regenerative braking improvement compared to...will be cycle dependent. A high speed drive cycle may for example drive a focus on aerodynamic improvements, while high frequency of braking will

Increased body size along urbanization gradients at both community and intraspecific level in macro-moths.

PubMed

Merckx, Thomas; Kaiser, Aurélien; Van Dyck, Hans

2018-05-23

Urbanization involves a cocktail of human-induced rapid environmental changes and is forecasted to gain further importance. Urban-heat-island effects result in increased metabolic costs expected to drive shifts towards smaller body sizes. However, urban environments are also characterized by strong habitat fragmentation, often selecting for dispersal phenotypes. Here, we investigate to what extent, and at which spatial scale(s), urbanization drives body size shifts in macro-moths-an insect group characterized by positive size-dispersal links-at both the community and intraspecific level. Using light and bait trapping as part of a replicated, spatially nested sampling design, we show that despite the observed urban warming of their woodland habitat, macro-moth communities display considerable increases in community-weighted mean body size because of stronger filtering against small species along urbanization gradients. Urbanization drives intraspecific shifts towards increased body size too, at least for a third of species analysed. These results indicate that urbanization drives shifts towards larger, and hence, more mobile species and individuals in order to mitigate low connectivity of ecological resources in urban settings. Macro-moths are a key group within terrestrial ecosystems, and since body size is central to species interactions, such urbanization-driven phenotypic change may impact urban ecosystem functioning, especially in terms of nocturnal pollination and food web dynamics. Although we show that urbanization's size-biased filtering happens simultaneously and coherently at both the inter- and intraspecific level, we demonstrate that the impact at the community level is most pronounced at the 800 m radius scale, whereas species-specific size increases happen at local and landscape scales (50-3,200 m radius), depending on the species. Hence, measures-such as creating and improving urban green infrastructure-to mitigate the effects of urbanization on body size will have to be implemented at multiple spatial scales in order to be most effective. © 2018 John Wiley & Sons Ltd.

The Urban Fabric of the City as Its Affects Thermal Energy Responses Derived from Remote Sensing Data

NASA Technical Reports Server (NTRS)

Quattrochi, Dale A.; Luvall, Jeffrey C.; Estes, Maurice G., Jr.

2000-01-01

The physical geography of the city affects numerous aspects of its interlinked biophysical, social, and land-atmosphere characteristics - those attributes that come together to form the total urban environment. One approach to studying the multitude of interactions that occur as a result of urbanization is to view the city from a systems ecology perspective, where energy and material cycle into and out of the urban milieu. Thus, the urban ecosystem is synergistic in linking land, air, water, and living organisms in a vast network of interrelated physical, human, and biological process. Given the number and the shear complexity of the exchanges and, ultimately, their effects, that occur within the urban environment, we are focusing our research on looking at how the morphology or urban fabric of the city, drives thermal energy exchanges across the urban landscape. The study of thermal energy attributes for different cities provides insight into how thermal fluxes and characteristics are partitioned across the city landscape in response to each city's morphology. We are using thermal infrared remote sensing data obtained at a high spatial resolution from aircraft, along with satellite data, to identify and quantify thermal energy characteristics for 4 U.S. cities: Atlanta, GA, Baton Rouge, LA, Salt Lake City, UT, and Sacramento, CA. Analysis of how thermal energy is spatially distributed across the urban landscapes for these cities provides a unique perspective for understanding how the differing morphology of cities forces land-atmosphere exchanges, such as the urban heat island effect, as well as related meteorological and air quality interactions. Keyword: urban ecosystems, remote sensing, urban heat island

Spatial Patterns of Greenhouse Gases Across an Urbanization Gradient in a Suburban River Network

NASA Astrophysics Data System (ADS)

Robison, A.; Balch, E.; Wollheim, W. M.

2017-12-01

River networks are important components of the global carbon cycle, processing significant quantities of terrestrial carbon and are most often sources of greenhouse gases (GHGs) to the atmosphere. While recent investigations have begun to incorporate aquatic systems into continental carbon budgets, our understanding of what drives the variability in space and time of these dynamics is poorly constrained. Meanwhile, urban areas continue to expand rapidly across the globe, with wide ranging effects on aquatic systems. A better understanding of the effect of human activities on aquatic carbon and GHG dynamics at both local and global scales is needed. We address the question: How does urbanization affect GHG dynamics in river networks? To address this question, we conducted a synoptic survey of 45 sites in a suburban river network in New England (Ipswich River, MA), analyzing samples for physical and chemical characteristics, including dissolved GHGs, carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Sampling sites were selected across an urbanization gradient (1.4-90% developed) and included headwater streams, major tributaries, the basin mouth, and additional sites along the main stem. Initial results indicate dissolved N2O concentration in headwater streams is related to catchment development, while CO2 and CH4 are not correlated to land use generally. CO2 and CH4 signals from urban areas are likely modified by fluvial wetlands that are abundant along larger tributaries and the mainstem. Developed watersheds are inherently altered and heterogeneous landscapes. To fully quantify the role of urbanized waters in the larger carbon cycle, GHG dynamics must be considered at the river network scale. The work presented here begins this process, allowing for an examination of the interaction between land use and GHG concentrations. Additional analyses will focus on further constraining GHG patterns across the river network, and modeling gas transport through and flux out of the system. This relationship should also be examined across time and under varying flow conditions.

Heavy-Duty Vehicle Port Drayage Drive Cycle Characterization and Development

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

Prohaska, Robert; Konan, Arnaud; Kelly, Kenneth

In an effort to better understand the operational requirements of port drayage vehicles and their potential for adoption of advanced technologies, National Renewable Energy Laboratory (NREL) researchers collected over 36,000 miles of in-use duty cycle data from 30 Class 8 drayage trucks operating at the Port of Long Beach and Port of Los Angeles in Southern California. These data include 1-Hz global positioning system location and SAE J1939 high-speed controller area network information. Researchers processed the data through NREL's Drive-Cycle Rapid Investigation, Visualization, and Evaluation tool to examine vehicle kinematic and dynamic patterns across the spectrum of operations. Using themore » k-medoids clustering method, a repeatable and quantitative process for multi-mode drive cycle segmentation, the analysis led to the creation of multiple drive cycles representing four distinct modes of operation that can be used independently or in combination. These drive cycles are statistically representative of real-world operation of port drayage vehicles. When combined with modeling and simulation tools, these representative test cycles allow advanced vehicle or systems developers to efficiently and accurately evaluate vehicle technology performance requirements to reduce cost and development time while ultimately leading to the commercialization of advanced technologies that meet the performance requirements of the port drayage vocation. The drive cycles, which are suitable for chassis dynamometer testing, were compared to several existing test cycles. This paper presents the clustering methodology, accompanying results of the port drayage duty cycle analysis and custom drive cycle creation.« less

Heavy-Duty Vehicle Port Drayage Drive Cycle Characterization and Development: Preprint

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

Prohaska, Robert; Konan, Arnaud; Kelly, Kenneth

In an effort to better understand the operational requirements of port drayage vehicles and their potential for adoption of advanced technologies, National Renewable Energy Laboratory (NREL) researchers collected over 36,000 miles of in-use duty cycle data from 30 Class 8 drayage trucks operating at the Port of Long Beach and Port of Los Angeles in Southern California. These data include 1-Hz global positioning system location and SAE J1939 high-speed controller area network information. Researchers processed the data through NREL's Drive-Cycle Rapid Investigation, Visualization, and Evaluation tool to examine vehicle kinematic and dynamic patterns across the spectrum of operations. Using themore » k-medoids clustering method, a repeatable and quantitative process for multi-mode drive cycle segmentation, the analysis led to the creation of multiple drive cycles representing four distinct modes of operation that can be used independently or in combination. These drive cycles are statistically representative of real-world operation of port drayage vehicles. When combined with modeling and simulation tools, these representative test cycles allow advanced vehicle or systems developers to efficiently and accurately evaluate vehicle technology performance requirements to reduce cost and development time while ultimately leading to the commercialization of advanced technologies that meet the performance requirements of the port drayage vocation. The drive cycles, which are suitable for chassis dynamometer testing, were compared to several existing test cycles. This paper presents the clustering methodology, accompanying results of the port drayage duty cycle analysis and custom drive cycle creation.« less

Heavy-Duty Vehicle Port Drayage Drive Cycle Characterization and Development

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

Prohaska, Robert; Konan, Arnaud; Kelly, Kenneth

2016-05-02

In an effort to better understand the operational requirements of port drayage vehicles and their potential for adoption of advanced technologies, National Renewable Energy Laboratory (NREL) researchers collected over 36,000 miles of in-use duty cycle data from 30 Class 8 drayage trucks operating at the Port of Long Beach and Port of Los Angeles in Southern California. These data include 1-Hz global positioning system location and SAE J1939 high-speed controller area network information. Researchers processed the data through NREL's Drive-Cycle Rapid Investigation, Visualization, and Evaluation tool to examine vehicle kinematic and dynamic patterns across the spectrum of operations. Using themore » k-medoids clustering method, a repeatable and quantitative process for multi-mode drive cycle segmentation, the analysis led to the creation of multiple drive cycles representing four distinct modes of operation that can be used independently or in combination. These drive cycles are statistically representative of real-world operation of port drayage vehicles. When combined with modeling and simulation tools, these representative test cycles allow advanced vehicle or systems developers to efficiently and accurately evaluate vehicle technology performance requirements to reduce cost and development time while ultimately leading to the commercialization of advanced technologies that meet the performance requirements of the port drayage vocation. The drive cycles, which are suitable for chassis dynamometer testing, were compared to several existing test cycles. This paper presents the clustering methodology, accompanying results of the port drayage duty cycle analysis and custom drive cycle creation.« less

Modeling Heavy/Medium-Duty Fuel Consumption Based on Drive Cycle Properties

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

Wang, Lijuan; Duran, Adam; Gonder, Jeffrey

This paper presents multiple methods for predicting heavy/medium-duty vehicle fuel consumption based on driving cycle information. A polynomial model, a black box artificial neural net model, a polynomial neural network model, and a multivariate adaptive regression splines (MARS) model were developed and verified using data collected from chassis testing performed on a parcel delivery diesel truck operating over the Heavy Heavy-Duty Diesel Truck (HHDDT), City Suburban Heavy Vehicle Cycle (CSHVC), New York Composite Cycle (NYCC), and hydraulic hybrid vehicle (HHV) drive cycles. Each model was trained using one of four drive cycles as a training cycle and the other threemore » as testing cycles. By comparing the training and testing results, a representative training cycle was chosen and used to further tune each method. HHDDT as the training cycle gave the best predictive results, because HHDDT contains a variety of drive characteristics, such as high speed, acceleration, idling, and deceleration. Among the four model approaches, MARS gave the best predictive performance, with an average absolute percent error of -1.84% over the four chassis dynamometer drive cycles. To further evaluate the accuracy of the predictive models, the approaches were first applied to real-world data. MARS outperformed the other three approaches, providing an average absolute percent error of -2.2% of four real-world road segments. The MARS model performance was then compared to HHDDT, CSHVC, NYCC, and HHV drive cycles with the performance from Future Automotive System Technology Simulator (FASTSim). The results indicated that the MARS method achieved a comparative predictive performance with FASTSim.« less

Urban scale air quality modelling using detailed traffic emissions estimates

NASA Astrophysics Data System (ADS)

Borrego, C.; Amorim, J. H.; Tchepel, O.; Dias, D.; Rafael, S.; Sá, E.; Pimentel, C.; Fontes, T.; Fernandes, P.; Pereira, S. R.; Bandeira, J. M.; Coelho, M. C.

2016-04-01

The atmospheric dispersion of NOx and PM10 was simulated with a second generation Gaussian model over a medium-size south-European city. Microscopic traffic models calibrated with GPS data were used to derive typical driving cycles for each road link, while instantaneous emissions were estimated applying a combined Vehicle Specific Power/Co-operative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (VSP/EMEP) methodology. Site-specific background concentrations were estimated using time series analysis and a low-pass filter applied to local observations. Air quality modelling results are compared against measurements at two locations for a 1 week period. 78% of the results are within a factor of two of the observations for 1-h average concentrations, increasing to 94% for daily averages. Correlation significantly improves when background is added, with an average of 0.89 for the 24 h record. The results highlight the potential of detailed traffic and instantaneous exhaust emissions estimates, together with filtered urban background, to provide accurate input data to Gaussian models applied at the urban scale.

Spatiotemporal variability of urban growth factors: A global and local perspective on the megacity of Mumbai

NASA Astrophysics Data System (ADS)

Shafizadeh-Moghadam, Hossein; Helbich, Marco

2015-03-01

The rapid growth of megacities requires special attention among urban planners worldwide, and particularly in Mumbai, India, where growth is very pronounced. To cope with the planning challenges this will bring, developing a retrospective understanding of urban land-use dynamics and the underlying driving-forces behind urban growth is a key prerequisite. This research uses regression-based land-use change models - and in particular non-spatial logistic regression models (LR) and auto-logistic regression models (ALR) - for the Mumbai region over the period 1973-2010, in order to determine the drivers behind spatiotemporal urban expansion. Both global models are complemented by a local, spatial model, the so-called geographically weighted logistic regression (GWLR) model, one that explicitly permits variations in driving-forces across space. The study comes to two main conclusions. First, both global models suggest similar driving-forces behind urban growth over time, revealing that LRs and ALRs result in estimated coefficients with comparable magnitudes. Second, all the local coefficients show distinctive temporal and spatial variations. It is therefore concluded that GWLR aids our understanding of urban growth processes, and so can assist context-related planning and policymaking activities when seeking to secure a sustainable urban future.

Impact factors on expansion of built-up areas in Zhejiang Province, China

NASA Astrophysics Data System (ADS)

Liu, Dong; Zhu, Qiankun; Li, Yan; Gong, Fang

2017-10-01

Built-up areas are the results of human activities. Not only are they the real reflection of human and society activities, but also one of the most important input parameters for the simulation of biogeochemical cycle. Therefore, it is very necessary to map the distribution of built-up areas and monitor their changes by using new technologies and methods at high spatiotemporal resolution. By combining technologies of GIS (Geographic Information System) and RS (Remote Sensing), this study mainly explored the expansion and driving factors of built-up areas at the beginning of the 21st century in Zhejiang Province, China. Firstly, it introduced the mapping processes of LULC (Land Use and Land Cover) based on the method which combined object-oriented method and binary decision tree. Then, it analyzed the expansion features of built-up areas in Zhejiang from 2000 to 2005 and 2005 to 2010. In addition to these, potential driving factors on the expansion of built-up areas were also explored, which contained physical geographical factors, railways, highways, rivers, urban centers, elevation, and slop. Results revealed that the expansions of built-up areas in Zhejiang from 2000 to 2005 and from 2005 to 2010 were very obvious and they showed high levels of variation in spatial heterogeneity. Except those, increased built-up areas with distance to railways, highways, rivers, and urban centers could be fitted with power function (y = a*xb ), with minimum R2 of 0.9507 for urban centers from 2000 to 2005; the increased permillages of built-up areas to mean elevation and mean slop could be fitted with exponential functions (y = a*ebx), with minimum R2 of 0.6657 for mean slop from 2005 to 2010. Besides, government policy could also impact expansion of built-up areas. In a nutshell, a series of conclusions were obtained through this study about the spatial features and driving factors of evolution of built-up areas in Zhejiang from 2000 to 2010.

Driving mechanism and sources of groundwater nitrate contamination in the rapidly urbanized region of south China

NASA Astrophysics Data System (ADS)

Zhang, Qianqian; Sun, Jichao; Liu, Jingtao; Huang, Guanxing; Lu, Chuan; Zhang, Yuxi

2015-11-01

Nitrate contamination of groundwater has become an environmental problem of widespread concern in China. We collected 899 groundwater samples from a rapidly urbanized area, in order to identify the main sources and driving mechanisms of groundwater nitrate contamination. The results showed that the land use has a significant effect on groundwater nitrate concentration (P < 0.001). Landfill leakage was an important source of nitrate in groundwater in the PRD (Pearl River Delta) region, since landfill yielded the highest nitrate concentration (38.14 mg/L) and the highest ratio of exceeded standard (42.50%). In this study, the driving mechanism of groundwater nitrate contamination was determined to be urban construction and the secondary and tertiary industrial development, and population growth. This study revealed that domestic wastewater and industrial wastewater were the main sources of groundwater nitrate pollution. Therefore, the priority method for relieving groundwater nitrate contamination is to control the random discharge of domestic and industrial wastewater in regions undergoing rapid urbanization. Capsule abstract. The main driving mechanism of groundwater nitrate contamination was determined to be urban construction and the secondary and tertiary industrial development, and population growth.

Driving mechanism and sources of groundwater nitrate contamination in the rapidly urbanized region of south China.

PubMed

Zhang, Qianqian; Sun, Jichao; Liu, Jingtao; Huang, Guanxing; Lu, Chuan; Zhang, Yuxi

2015-11-01

Nitrate contamination of groundwater has become an environmental problem of widespread concern in China. We collected 899 groundwater samples from a rapidly urbanized area, in order to identify the main sources and driving mechanisms of groundwater nitrate contamination. The results showed that the land use has a significant effect on groundwater nitrate concentration (P<0.001). Landfill leakage was an important source of nitrate in groundwater in the PRD (Pearl River Delta) region, since landfill yielded the highest nitrate concentration (38.14 mg/L) and the highest ratio of exceeded standard (42.50%). In this study, the driving mechanism of groundwater nitrate contamination was determined to be urban construction and the secondary and tertiary industrial development, and population growth. This study revealed that domestic wastewater and industrial wastewater were the main sources of groundwater nitrate pollution. Therefore, the priority method for relieving groundwater nitrate contamination is to control the random discharge of domestic and industrial wastewater in regions undergoing rapid urbanization. Capsule abstract. The main driving mechanism of groundwater nitrate contamination was determined to be urban construction and the secondary and tertiary industrial development, and population growth. Copyright © 2015 Elsevier B.V. All rights reserved.

Risk and safety perception on urban and rural roads: Effects of environmental features, driver age and risk sensitivity.

PubMed

Cox, Jolene A; Beanland, Vanessa; Filtness, Ashleigh J

2017-10-03

The ability to detect changing visual information is a vital component of safe driving. In addition to detecting changing visual information, drivers must also interpret its relevance to safety. Environmental changes considered to have high safety relevance will likely demand greater attention and more timely responses than those considered to have lower safety relevance. The aim of this study was to explore factors that are likely to influence perceptions of risk and safety regarding changing visual information in the driving environment. Factors explored were the environment in which the change occurs (i.e., urban vs. rural), the type of object that changes, and the driver's age, experience, and risk sensitivity. Sixty-three licensed drivers aged 18-70 years completed a hazard rating task, which required them to rate the perceived hazardousness of changing specific elements within urban and rural driving environments. Three attributes of potential hazards were systematically manipulated: the environment (urban, rural); the type of object changed (road sign, car, motorcycle, pedestrian, traffic light, animal, tree); and its inherent safety risk (low risk, high risk). Inherent safety risk was manipulated by either varying the object's placement, on/near or away from the road, or altering an infrastructure element that would require a change to driver behavior. Participants also completed two driving-related risk perception tasks, rating their relative crash risk and perceived risk of aberrant driving behaviors. Driver age was not significantly associated with hazard ratings, but individual differences in perceived risk of aberrant driving behaviors predicted hazard ratings, suggesting that general driving-related risk sensitivity plays a strong role in safety perception. In both urban and rural scenes, there were significant associations between hazard ratings and inherent safety risk, with low-risk changes perceived as consistently less hazardous than high-risk impact changes; however, the effect was larger for urban environments. There were also effects of object type, with certain objects rated as consistently more safety relevant. In urban scenes, changes involving pedestrians were rated significantly more hazardous than all other objects, and in rural scenes, changes involving animals were rated as significantly more hazardous. Notably, hazard ratings were found to be higher in urban compared with rural driving environments, even when changes were matched between environments. This study demonstrates that drivers perceive rural roads as less risky than urban roads, even when similar scenarios occur in both environments. Age did not affect hazard ratings. Instead, the findings suggest that the assessment of risk posed by hazards is influenced more by individual differences in risk sensitivity. This highlights the need for driver education to account for appraisal of hazards' risk and relevance, in addition to hazard detection, when considering factors that promote road safety.

Impact of biodiesel and renewable diesel on emissions of regulated pollutants and greenhouse gases on a 2000 heavy duty diesel truck

NASA Astrophysics Data System (ADS)

Na, Kwangsam; Biswas, Subhasis; Robertson, William; Sahay, Keshav; Okamoto, Robert; Mitchell, Alexander; Lemieux, Sharon

2015-04-01

As part of a broad evaluation of the environmental impacts of biodiesel and renewable diesel as alternative motor fuels and fuel blends in California, the California Air Resources Board's (CARB) Heavy-duty Diesel Emission Testing Laboratory conducted chassis dynamometer exhaust emission measurements on in-use heavy-heavy-duty diesel trucks (HHDDT). The results presented here detail the impact of biodiesel and renewable diesel fuels and fuel blends as compared to CARB ULSD on particulate matter (PM), regulated gases, and two greenhouse gases emissions from a HHDDT with a 2000 C15 Caterpillar engine with no exhaust after treatment devices. This vehicle was tested over the Urban Dynamometer Driving Schedule (UDDS) and the cruise portion of the California HHDDT driving schedule. Three neat blend stocks (soy-based and animal-based fatty acid methyl ester (FAME) biodiesels, and a renewable diesel) and CARB-certified ultra-low sulfur diesel (CARB ULSD) along with their 20% and 50% blends (blended with CARB ULSD) were tested. The effects of blend level on emission characteristics were discussed on g·km-1 basis. The results showed that PM, total hydrocarbon (THC), and carbon monoxide (CO) emissions were dependent on driving cycles, showing higher emissions for the UDDS cycles with medium load than the highway cruise cycle with high load on per km basis. When comparing CARB ULSD to biodiesels and renewable diesel blends, it was observed that the PM, THC, and CO emissions decreased with increasing blend levels regardless of the driving cycles. Note that biodiesel blends showed higher degree of emission reductions for PM, THC, and CO than renewable diesel blends. Both biodiesels and renewable diesel blends effectively reduced PM emissions, mainly due to reduction in elemental carbon emissions (EC), however no readily apparent reductions in organic carbon (OC) emissions were observed. When compared to CARB ULSD, soy- and animal-based biodiesel blends showed statistically significant increases in nitrogen oxides (NOx) emissions for 50% or higher biodiesel blends. The 20% blends of the biodiesels showed no statistically significant effect on NOx emissions on any cycle. In contrast, renewable diesel slightly decreased NOx emissions and the degree of reduction was statistically significant for 50% or higher blends over the UDDS cycle, but not at the 20% blends. The highway cruise cycles did not show a statistically strong NOx emission trend with increasing blend level of renewable diesel. Biodiesel and renewable fuel impacts on two greenhouse gases, CO2 and N2O emissions were of lower magnitude when compared to other regulated pollutants emissions, showing a change in their emissions within approximately ±3% from the CARB ULSD.

Gaseous emissions from compressed natural gas buses in urban road and highway tests in China.

PubMed

Yue, Tingting; Chai, Fahe; Hu, Jingnan; Jia, Ming; Bao, Xiaofeng; Li, Zhenhua; He, Liqang; Zu, Lei

2016-10-01

The natural gas vehicle market is rapidly developing throughout the world, and the majority of such vehicles operate on compressed natural gas (CNG). However, most studies on the emission characteristics of CNG vehicles rely on laboratory chassis dynamometer measurements, which do not accurately represent actual road driving conditions. To further investigate the emission characteristics of CNG vehicles, two CNG city buses and two CNG coaches were tested on public urban roads and highway sections. Our results show that when speeds of 0-10km/hr were increased to 10-20km/hr, the CO 2 , CO, nitrogen oxide (NO x ), and total hydrocarbon (THC) emission factors decreased by (71.6±4.3)%, (65.6±9.5)%, (64.9±9.2)% and (67.8±0.3)%, respectively. In this study, The Beijing city buses with stricter emission standards (Euro IV) did not have lower emission factors than the Chongqing coaches with Euro II emission standards. Both the higher emission factors at 0-10km/hr speeds and the higher percentage of driving in the low-speed regime during the entire road cycle may have contributed to the higher CO 2 and CO emission factors of these city buses. Additionally, compared with the emission factors produced in the urban road tests, the CO emission factors of the CNG buses in highway tests decreased the most (by 83.2%), followed by the THC emission factors, which decreased by 67.1%. Copyright © 2016. Published by Elsevier B.V.

Integrated urban water cycle management: the UrbanCycle model.

PubMed

Hardy, M J; Kuczera, G; Coombes, P J

2005-01-01

Integrated urban water cycle management presents a new framework in which solutions to the provision of urban water services can be sought. It enables new and innovative solutions currently constrained by the existing urban water paradigm to be implemented. This paper introduces the UrbanCycle model. The model is being developed in response to the growing and changing needs of the water management sector and in light of the need for tools to evaluate integrated watercycle management approaches. The key concepts underpinning the UrbanCycle model are the adoption of continuous simulation, hierarchical network modelling, and the careful management of computational complexity. The paper reports on the integration of modelling capabilities across the allotment, and subdivision scales, enabling the interactions between these scales to be explored. A case study illustrates the impacts of various mitigation measures possible under an integrated water management framework. The temporal distribution of runoff into ephemeral streams from a residential allotment in Western Sydney is evaluated and linked to the geomorphic and ecological regimes in receiving waters.

Physical environmental factors related to walking and cycling in older adults: the Belgian aging studies

PubMed Central

2012-01-01

Background Socio-ecological models emphasize the relationship between the physical environment and physical activity (PA). However, knowledge about this relationship in older adults is limited. Therefore, the present study aims to investigate the relationship between area of residence (urban, semi-urban or rural) and older adults' walking and cycling for transportation and recreation. Additionally, relationships between several physical environmental factors and walking and cycling and possible moderating effects of area of residence, age and gender were studied. Methods Data from 48,879 Flemish older adults collected in 2004-2010 through peer research were analyzed. Walking, cycling and environmental perceptions were assessed using self-administered questionnaires. The Study Service of the Flemish Government provided objective data on municipal characteristics. Multilevel logistic regression analyses were applied. Results Urban participants were more likely to walk daily for transportation compared to rural (OR = 1.43; 95% CI = 1.22, 1.67) and semi-urban participants (OR = 1.32; 95% CI = 1.13, 1.54). Urban participants were less likely to cycle daily for transportation compared to semi-urban participants (OR = 0.72; 95% CI = 0.56, 0.92). Area of residence was unrelated to weekly recreational walking/cycling. Perceived short distances to services (ORs ranging from 1.04 to 1.19) and satisfaction with public transport (ORs ranging from 1.07 to 1.13) were significantly positively related to all walking/cycling behaviors. Feelings of unsafety was negatively related to walking for transportation (OR = 0.93, 95% CI = 0.91, 0.95) and recreational walking/cycling (OR = 0.95, 95% CI = 0.92, 0.97). In females, it was also negatively related to cycling for transportation (OR = 0.94, 95% CI = 0.90, 0.98). Conclusions Urban residents were more likely to walk for transportation daily compared to semi-urban and rural residents. Daily cycling for transportation was less prevalent among urban compared to semi-urban residents. Access to destinations appeared to be important for promoting both walking and cycling for transportation and recreation across all demographic subgroups. Additionaly, feelings of unsafety were associated with lower rates of walking for transportation and walking/cycling for recreation in all subgroups and cycling for transportation in females. No clear patterns emerged for other environmental factors. PMID:22361255

Physical environmental factors related to walking and cycling in older adults: the Belgian aging studies.

PubMed

Van Cauwenberg, Jelle; Clarys, Peter; De Bourdeaudhuij, Ilse; Van Holle, Veerle; Verté, Dominique; De Witte, Nico; De Donder, Liesbeth; Buffel, Tine; Dury, Sarah; Deforche, Benedicte

2012-02-23

Socio-ecological models emphasize the relationship between the physical environment and physical activity (PA). However, knowledge about this relationship in older adults is limited. Therefore, the present study aims to investigate the relationship between area of residence (urban, semi-urban or rural) and older adults' walking and cycling for transportation and recreation. Additionally, relationships between several physical environmental factors and walking and cycling and possible moderating effects of area of residence, age and gender were studied. Data from 48,879 Flemish older adults collected in 2004-2010 through peer research were analyzed. Walking, cycling and environmental perceptions were assessed using self-administered questionnaires. The Study Service of the Flemish Government provided objective data on municipal characteristics. Multilevel logistic regression analyses were applied. Urban participants were more likely to walk daily for transportation compared to rural (OR = 1.43; 95% CI = 1.22, 1.67) and semi-urban participants (OR = 1.32; 95% CI = 1.13, 1.54). Urban participants were less likely to cycle daily for transportation compared to semi-urban participants (OR = 0.72; 95% CI = 0.56, 0.92). Area of residence was unrelated to weekly recreational walking/cycling. Perceived short distances to services (ORs ranging from 1.04 to 1.19) and satisfaction with public transport (ORs ranging from 1.07 to 1.13) were significantly positively related to all walking/cycling behaviors. Feelings of unsafety was negatively related to walking for transportation (OR = 0.93, 95% CI = 0.91, 0.95) and recreational walking/cycling (OR = 0.95, 95% CI = 0.92, 0.97). In females, it was also negatively related to cycling for transportation (OR = 0.94, 95% CI = 0.90, 0.98). Urban residents were more likely to walk for transportation daily compared to semi-urban and rural residents. Daily cycling for transportation was less prevalent among urban compared to semi-urban residents. Access to destinations appeared to be important for promoting both walking and cycling for transportation and recreation across all demographic subgroups. Additionaly, feelings of unsafety were associated with lower rates of walking for transportation and walking/cycling for recreation in all subgroups and cycling for transportation in females. No clear patterns emerged for other environmental factors.

A systematic approach for electrochemical-thermal modelling of a large format lithium-ion battery for electric vehicle application

NASA Astrophysics Data System (ADS)

Hosseinzadeh, Elham; Genieser, Ronny; Worwood, Daniel; Barai, Anup; Marco, James; Jennings, Paul

2018-04-01

A 1D electrochemical-thermal model is developed to characterise the behaviour of a 53 Ah large format pouch cell with LiNixMnyCo1-x-yO2 (NMC) chemistry over a wide range of operating conditions, including: continuous charge (0.5C-2C), continuous discharge (0.5C-5C) and operation of the battery within an electric vehicle (EV) over an urban drive-cycle (WLTP Class 3) and for a high performance EV being driven under track racing conditions. The 1D model of one electrode pair is combined with a 3D thermal model of a cell to capture the temperature distribution at the cell scale. Performance of the model is validated for an ambient temperature range of 5 °C-45 °C. Results highlight that battery performance is highly dependent on ambient temperature. By decreasing the ambient temperature from 45 °C to 5 °C, the available energy drops by 17.1% and 7.8% under 0.5C and 5C discharge respectively. Moreover, the corresponding power loss is found to be: 5.23% under the race cycle as compared with 7.57% under the WLTP drive cycle. Formulation of the model is supported by a comprehensive set of experiments, for quantifying key parameters and for model validation. The full parameter-set for the model is provided ensuring the model is a valuable resource to underpin further research.

The urban forest and ecosystem services: impact on urban water, heat, and pollution cycles at the tree, street, and city scale

Treesearch

S. J. Livesley; E. G. McPherson; C. Calfapietra

2016-01-01

Many environmental challenges are exacerbated within the urban landscape, such as stormwater runoff and flood risk, chemical and particulate pollution of urban air, soil and water, the urban heat island, and summer heat waves. Urban trees, and the urban forest as a whole, can be managed to have an impact on the urban water, heat, carbon and pollution cycles. However,...

School and Intermediate License Drive-Cam Study [Mobile .MP4 (480x320/29.97fps/21.7MB)

DOT National Transportation Integrated Search

2011-07-05

This project builds on two successful rural and urban teen driving studies that have been completed in rural Iowa and urban Minneapolis. The study will recruit 60 new drivers from five rural high schools in Eastern Iowa. During the three-year study d...

School and Intermediate License Drive-Cam Study [SD .MP4 (640x424/29.97fps/34.5MB)

DOT National Transportation Integrated Search

2011-07-05

This project builds on two successful rural and urban teen driving studies that have been completed in rural Iowa and urban Minneapolis. The study will recruit 60 new drivers from five rural high schools in Eastern Iowa. During the three-year study d...

40 CFR 600.109-08 - EPA driving cycles.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ECONOMY AND GREENHOUSE GAS EXHAUST EMISSIONS OF MOTOR VEHICLES Fuel Economy and Carbon-Related Exhaust....115 of this chapter. (b) The highway fuel economy driving cycle is specified in this paragraph. (1) The Highway Fuel Economy Driving Schedule is set forth in appendix I of this part. The driving...

40 CFR 600.109-08 - EPA driving cycles.

Code of Federal Regulations, 2013 CFR

2013-07-01

... ECONOMY AND GREENHOUSE GAS EXHAUST EMISSIONS OF MOTOR VEHICLES Fuel Economy and Carbon-Related Exhaust....115 of this chapter. (b) The highway fuel economy driving cycle is specified in this paragraph. (1) The Highway Fuel Economy Driving Schedule is set forth in appendix I of this part. The driving...

Reactivity-controlled compression ignition drive cycle emissions and fuel economy estimations using vehicle system simulations

DOE PAGES

Curran, Scott J.; Gao, Zhiming; Wagner, Robert M.

2014-12-22

In-cylinder blending of gasoline and diesel to achieve reactivity-controlled compression ignition has been shown to reduce NO X and soot emissions while maintaining or improving brake thermal efficiency as compared with conventional diesel combustion. The reactivity-controlled compression ignition concept has an advantage over many advanced combustion strategies in that the fuel reactivity can be tailored to the engine speed and load, allowing stable low-temperature combustion to be extended over more of the light-duty drive cycle load range. In this paper, a multi-mode reactivity-controlled compression ignition strategy is employed where the engine switches from reactivity-controlled compression ignition to conventional diesel combustionmore » when speed and load demand are outside of the experimentally determined reactivity-controlled compression ignition range. The potential for reactivity-controlled compression ignition to reduce drive cycle fuel economy and emissions is not clearly understood and is explored here by simulating the fuel economy and emissions for a multi-mode reactivity-controlled compression ignition–enabled vehicle operating over a variety of US drive cycles using experimental engine maps for multi-mode reactivity-controlled compression ignition, conventional diesel combustion, and a 2009 port-fuel injected gasoline engine. Drive cycle simulations are completed assuming a conventional mid-size passenger vehicle with an automatic transmission. Multi-mode reactivity-controlled compression ignition fuel economy simulation results are compared with the same vehicle powered by a representative 2009 port-fuel injected gasoline engine over multiple drive cycles. Finally, engine-out drive cycle emissions are compared with conventional diesel combustion, and observations regarding relative gasoline and diesel tank sizes needed for the various drive cycles are also summarized.« less

Influence of driving cycles on unit emissions from passenger cars

NASA Astrophysics Data System (ADS)

Joumard, R.; André, M.; Vidon, R.; Tassel, P.; Pruvost, C.

Small samples of petrol engine or diesel cars, equipped with or without catalysts, were tested over 36 driving cycles divided into four categories - standard cycles and three sets of cycles more representative of real-world driving conditions. The tests addressed standard gaseous pollutants and fuel consumption and also less frequently measured pollutant such as CH 4. In the first part of this paper we examine cold emissions in order to assess the duration of the cold start impact and the representativity of the cold ECE15 cycle. Then unit emissions are compared over the four driving cycle families. As compared to representative cycles, the standardised cycles underestimate hot emissions by almost 50% for petrol engine cars and 30% for diesel vehicles. Conversely, the results obtained for the three representative cycle families are in relatively close agreement with each other - within approximately 10%. However, the cinematic properties of the three families differ. Finally, we demonstrate that weighting all emission data equally, not taking into account the weight of each cycle in overall traffic, introduces significant biases, particularly when plotting emission vs. average speed curves.

Variability in soil CO2 efflux across distinct urban land cover types

NASA Astrophysics Data System (ADS)

Weissert, Lena F.; Salmond, Jennifer A.; Schwendenmann, Luitgard

2015-04-01

As a main source of greenhouse gases urban areas play an important role in the global carbon cycle. To assess the potential role of urban vegetation in mitigating carbon emissions we need information on the magnitude of biogenic CO2 emissions and its driving factors. We examined how urban land use types (urban forest, parklands, sportsfields) vary in their soil CO2 efflux. We measured soil CO2 efflux and its isotopic signature, soil temperature and soil moisture over a complete growing season in Auckland, New Zealand. Soil physical and chemical properties and vegetation characteristics were also measured. Mean soil CO2 efflux ranged from 4.15 to 12 μmol m-2 s-1. We did not find significant differences in soil CO2 efflux among land cover types due to high spatial variability in soil CO2 efflux among plots. Soil (soil carbon and nitrogen density, texture, soil carbon:nitrogen ratio) and vegetation characteristics (basal area, litter carbon density, grass biomass) were not significantly correlated with soil CO2 efflux. We found a distinct seasonal pattern with significantly higher soil CO2 efflux in autumn (Apr/May) and spring (Oct). In urban forests and sportsfields over 80% of the temporal variation was explained by soil temperature and soil water content. The δ13C signature of CO2 respired from parklands and sportsfields (-20 permil - -25 permil) were more positive compared to forest plots (-29 permil) indicating that parkland and sportsfields had a considerable proportion of C4 grasses. Despite the large intra-urban variability, our results compare to values reported from other, often climatically different cities, supporting the hypothesis of homogenization across urban areas as a result of human management practices.

Identifying the driving forces of urban expansion and its environmental impact in Jakarta-Bandung mega urban region

NASA Astrophysics Data System (ADS)

Pravitasari, A. E.; Rustiadi, E.; Mulya, S. P.; Setiawan, Y.; Fuadina, L. N.; Murtadho, A.

2018-05-01

The socio-economic development in Jakarta-Bandung Mega Urban Region (JBMUR) caused the increasing of urban expansion and led to a variety of environmental damage such as uncontrolled land use conversion and raising anthropogenic disaster. The objectives of this study are: (1) to identify the driving forces of urban expansion that occurs on JBMUR and (2) to analyze the environmental quality decline on JBMUR by producing time series spatial distribution map and spatial autocorrelation of floods and landslide as the proxy of anthropogenic disaster. The driving forces of urban expansion in this study were identified by employing Geographically Weighted Regression (GWR) model using 6 (six) independent variables, namely: population density, percentage of agricultural land, distance to the center of capital city/municipality, percentage of household who works in agricultural sector, distance to the provincial road, and distance to the local road. The GWR results showed that local demographic, social and economic factors including distance to the road spatially affect urban expansion in JBMUR. The time series spatial distribution map of floods and landslide event showed the spatial cluster of anthropogenic disaster in some areas. Through Local Moran Index, we found that environmental damage in one location has a significant impact on the condition of its surrounding area.

Fuel economy and life-cycle cost analysis of a fuel cell hybrid vehicle

NASA Astrophysics Data System (ADS)

Jeong, Kwi Seong; Oh, Byeong Soo

The most promising vehicle engine that can overcome the problem of present internal combustion is the hydrogen fuel cell. Fuel cells are devices that change chemical energy directly into electrical energy without combustion. Pure fuel cell vehicles and fuel cell hybrid vehicles (i.e. a combination of fuel cell and battery) as energy sources are studied. Considerations of efficiency, fuel economy, and the characteristics of power output in hybridization of fuel cell vehicle are necessary. In the case of Federal Urban Driving Schedule (FUDS) cycle simulation, hybridization is more efficient than a pure fuel cell vehicle. The reason is that it is possible to capture regenerative braking energy and to operate the fuel cell system within a more efficient range by using battery. Life-cycle cost is largely affected by the fuel cell size, fuel cell cost, and hydrogen cost. When the cost of fuel cell is high, hybridization is profitable, but when the cost of fuel cell is less than 400 US$/kW, a pure fuel cell vehicle is more profitable.

Real-time emission factor measurements of isocyanic acid from light duty gasoline vehicles.

PubMed

Brady, James M; Crisp, Timia A; Collier, Sonya; Kuwayama, Toshihiro; Forestieri, Sara D; Perraud, Véronique; Zhang, Qi; Kleeman, Michael J; Cappa, Christopher D; Bertram, Timothy H

2014-10-07

Exposure to gas-phase isocyanic acid (HNCO) has been previously shown to be associated with the development of atherosclerosis, cataracts and rheumatoid arthritis. As such, accurate emission inventories for HNCO are critical for modeling the spatial and temporal distribution of HNCO on a regional and global scale. To date, HNCO emission rates from light duty gasoline vehicles, operated under driving conditions, have not been determined. Here, we present the first measurements of real-time emission factors of isocyanic acid from a fleet of eight light duty gasoline-powered vehicles (LDGVs) tested on a chassis dynamometer using the Unified Driving Cycle (UC) at the California Air Resources Board (CARB) Haagen-Smit test facility, all of which were equipped with three-way catalytic converters. HNCO emissions were observed from all vehicles, in contrast to the idealized laboratory measurements. We report the tested fleet averaged HNCO emission factors, which depend strongly on the phase of the drive cycle; ranging from 0.46 ± 0.13 mg kg fuel(-1) during engine start to 1.70 ± 1.77 mg kg fuel(-1) during hard acceleration after the engine and catalytic converter were warm. The tested eight-car fleet average fuel based HNCO emission factor was 0.91 ± 0.58 mg kg fuel(-1), within the range previously estimated for light duty diesel-powered vehicles (0.21-3.96 mg kg fuel(-1)). Our results suggest that HNCO emissions from LDGVs represent a significant emission source in urban areas that should be accounted for in global and regional models.

Impact Factors Analysis of the Hot Side Temperature of Thermoelectric Module

NASA Astrophysics Data System (ADS)

Zhang, Xingyu; Tan, Gangfeng; Yang, Bo

2018-03-01

The thermoelectric generator (TEG) plays a crucial role in converting the waste energy of exhaust into electricity, which ensures energy saving and increased fuel utilization efficiency. In the urban driving cycle, frequent vehicle operation, like deceleration or acceleration, results in continuous variation of the exhaust temperature. In order to make the operating performance stable, and to weaken the adverse effects of the frequent variation of the exhaust temperature on the lifetime and work efficiency of the electronic components of TEG systems, the output voltage of the thermoelectric (TE) module should stay more stable. This article provides an improved method for the temperature stability of the TE material hot side based on sandwiching material. From the view of the TEG system's average output power and the hot side temperature stability of the TE material, the analyzing factors, including the fluctuation frequency of the exhaust temperature and the physical properties and thickness of the sandwiching material are evaluated, respectively, in the sine and new European driving cycle (NEDC) fluctuation condition of the exhaust temperature. The results show few effects of sandwiching material thickness with excellent thermal conductivity on the average output power. During the 150-170 s of the NEDC test condition, the minimum hot side temperatures with a BeO ceramic thickness of 2 mm and 6 mm are, respectively, 537.19 K and 685.70 K, which shows the obvious effect on the hot side temperature stability of the BeO ceramic thickness in the process of acceleration and deceleration of vehicle driving.

Impact Factors Analysis of the Hot Side Temperature of Thermoelectric Module

NASA Astrophysics Data System (ADS)

Zhang, Xingyu; Tan, Gangfeng; Yang, Bo

2017-12-01

The thermoelectric generator (TEG) plays a crucial role in converting the waste energy of exhaust into electricity, which ensures energy saving and increased fuel utilization efficiency. In the urban driving cycle, frequent vehicle operation, like deceleration or acceleration, results in continuous variation of the exhaust temperature. In order to make the operating performance stable, and to weaken the adverse effects of the frequent variation of the exhaust temperature on the lifetime and work efficiency of the electronic components of TEG systems, the output voltage of the thermoelectric (TE) module should stay more stable. This article provides an improved method for the temperature stability of the TE material hot side based on sandwiching material. From the view of the TEG system's average output power and the hot side temperature stability of the TE material, the analyzing factors, including the fluctuation frequency of the exhaust temperature and the physical properties and thickness of the sandwiching material are evaluated, respectively, in the sine and new European driving cycle (NEDC) fluctuation condition of the exhaust temperature. The results show few effects of sandwiching material thickness with excellent thermal conductivity on the average output power. During the 150-170 s of the NEDC test condition, the minimum hot side temperatures with a BeO ceramic thickness of 2 mm and 6 mm are, respectively, 537.19 K and 685.70 K, which shows the obvious effect on the hot side temperature stability of the BeO ceramic thickness in the process of acceleration and deceleration of vehicle driving.

Urban form and older residents' service use, walking, driving, quality of life, and neighborhood satisfaction.

PubMed

Patterson, Patricia K; Chapman, Nancy J

2004-01-01

This study explored the relationship between pedestrian-friendly urban form as reflected in new urbanism design guidelines, and neighborhood service use, walking, driving, quality of life, and neighborhood satisfaction among older women. A cross-sectional survey compared residents of census tracts similar indemographic characteristics but differing in urban form. The setting was urban and suburban areas of Portland, Oregon. The sample consisted of 372 females living alone over age 70 in six census tracts; 133 (36%) completed surveys. The New Urbanism Index rated the physical features of respondents' neighborhoods. The Neighborhood Resident Survey assessed travel modes and neighborhood satisfaction. The Quality of Life Index measured resident well-being. The Dartmouth COOP Functional Health Charts measured health status. Group comparisons were made with t-tests and regression analysis. Although limited by the cross-sectional design, the study showed that new urbanism partially explained several differences in service use and activity: distance to a grocery store (r2 change = .11, p = .001), number of services used within 1 mile from home (r2 change = .06, p = .007), number of walking activities (r2 change = .08, p = .001), number of services accessed by walking (r2 change = .14, p = .000), and number of services accessed by driving (r2 change = .05, p = .001). Traditional urban neighborhoods with mixed services and good pedestrian access were associated with increased walking among older residents.

40 CFR 86.010-18 - On-board Diagnostics for engines used in applications greater than 14,000 pounds GVWR.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... Further, for OBD monitors that run during engine-off conditions, the period of engine-off time following... drive cycle if the monitor has run and made one or more determinations during a drive cycle that the...) The monitor has run and made one or more determinations during a drive cycle that the malfunction is...

40 CFR 86.010-18 - On-board Diagnostics for engines used in applications greater than 14,000 pounds GVWR.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... Further, for OBD monitors that run during engine-off conditions, the period of engine-off time following... drive cycle if the monitor has run and made one or more determinations during a drive cycle that the...) The monitor has run and made one or more determinations during a drive cycle that the malfunction is...

40 CFR 86.010-18 - On-board Diagnostics for engines used in applications greater than 14,000 pounds GVWR.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... Further, for OBD monitors that run during engine-off conditions, the period of engine-off time following... drive cycle if the monitor has run and made one or more determinations during a drive cycle that the...) The monitor has run and made one or more determinations during a drive cycle that the malfunction is...

40 CFR 86.010-18 - On-board Diagnostics for engines used in applications greater than 14,000 pounds GVWR.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... Further, for OBD monitors that run during engine-off conditions, the period of engine-off time following... drive cycle if the monitor has run and made one or more determinations during a drive cycle that the...) The monitor has run and made one or more determinations during a drive cycle that the malfunction is...

Evolutionary algorithm for vehicle driving cycle generation.

PubMed

Perhinschi, Mario G; Marlowe, Christopher; Tamayo, Sergio; Tu, Jun; Wayne, W Scott

2011-09-01

Modeling transit bus emissions and fuel economy requires a large amount of experimental data over wide ranges of operational conditions. Chassis dynamometer tests are typically performed using representative driving cycles defined based on vehicle instantaneous speed as sequences of "microtrips", which are intervals between consecutive vehicle stops. Overall significant parameters of the driving cycle, such as average speed, stops per mile, kinetic intensity, and others, are used as independent variables in the modeling process. Performing tests at all the necessary combinations of parameters is expensive and time consuming. In this paper, a methodology is proposed for building driving cycles at prescribed independent variable values using experimental data through the concatenation of "microtrips" isolated from a limited number of standard chassis dynamometer test cycles. The selection of the adequate "microtrips" is achieved through a customized evolutionary algorithm. The genetic representation uses microtrip definitions as genes. Specific mutation, crossover, and karyotype alteration operators have been defined. The Roulette-Wheel selection technique with elitist strategy drives the optimization process, which consists of minimizing the errors to desired overall cycle parameters. This utility is part of the Integrated Bus Information System developed at West Virginia University.

Mechanism of Urban Water Dissipation: A Case Study in Xiamen Island

NASA Astrophysics Data System (ADS)

Zhou, J.; Liu, J.; Wang, Z.

2017-12-01

Urbanization have resulted in increasing water supply and water dissipation from water uses in urban areas, but traditional hydrological models usually ignores the dissipation from social water cycle. In order to comprehensively calculate the water vapor flux of urban natural - social binary water cycle, this study advanced the concept of urban water dissipation (UWD) to describe all form water transfer from liquid to gas in urban area. UWD units were divided according to the water consumption characteristics of the underlying surface, and experimental methods of investigation, statistics, observation and measurement were used to study the water dissipation of different units, determine the corresponding calculation method, and establish the UWD calculation model. Taking Xiamen Island as an example, the city's water dissipation in 2016 was calculated to be 850 mm and verified by water balance. The results showed that the contributions of water dissipation from the green land, building, hardened ground and water surface. The results means that water dissipation inside buildings was one main component of the total UWD. The proportion of water vapor fluxes exceeds the natural water cycle in the urban area. Social water cycle is the main part of the city's water cycle, and also the hot and focus of urban hydrology research in the future.

Alcohol consumption and cycling in contrast to driving.

PubMed

Hagemeister, Carmen; Kronmaier, Markus

2017-08-01

In Germany, the legal blood alcohol limit for cyclists is much higher (0.16 percent) than the limit for drivers (0.05 percent) - as long as no crash has occurred. The proportion of police-recorded crashes with personal damage under the influence is higher for cyclists than drivers, and the blood alcohol concentrations are higher for cyclists than drivers. 63 women and 204 men who drive a car and use a bike and drink alcohol participated in the online study. In the sample, cycling under the influence (CUI) was more frequent and was observed more frequently among friends than driving under the influence (DUI). Persons who use a particular vehicle type more often in general and when they visit friends also use it more often after alcohol consumption. Persons who drink alcohol more often cycle more often after alcohol consumption. In all aspects covered, drink cycling was seen as more acceptable and less dangerous than drink driving. Persons who cycle more often under the influence observe drink cycling more often among their friends. They think they are less of a danger to themselves and others when cycling after alcohol consumption, and they agree less with the statement that one should leave one's bike parked after alcohol consumption. The attitudes that drinking is unsafe for one's own driving and that one should leave one's car parked are important predictors of (non-)drink driving. For cycling, the most important predictors are bike use frequency and observing drink cycling among friends. Copyright © 2017 Elsevier Ltd. All rights reserved.

Are stormwater pollution impacts significant in life cycle assessment? A new methodology for quantifying embedded urban stormwater impacts.

PubMed

Phillips, Robert; Jeswani, Harish Kumar; Azapagic, Adisa; Apul, Defne

2018-09-15

Current life cycle assessment (LCA) models do not explicitly incorporate the impacts from urban stormwater pollution. To address this issue, a framework to estimate the impacts from urban stormwater pollution over the lifetime of a system has been developed, laying the groundwork for subsequent improvements in life cycle databases and LCA modelling. The proposed framework incorporates urban stormwater event mean concentration (EMC) data into existing LCA impact categories to account for the environmental impacts associated with urban land occupation across the whole life cycle of a system. It consists of five steps: (1) compilation of inventory of urban stormwater pollutants; (2) collection of precipitation data; (3) classification and characterisation within existing midpoint impact categories; (4) collation of inventory data for impermeable urban land occupation; and (5) impact assessment. The framework is generic and can be applied to any system using any LCA impact method. Its application is demonstrated by two illustrative case studies: electricity generation and production of construction materials. The results show that pollutants in urban stormwater have an influence on human toxicity, freshwater and marine ecotoxicity, marine eutrophication, freshwater eutrophication and terrestrial ecotoxicity. Among these, urban stormwater pollution has the highest relative contribution to the eutrophication potentials. The results also suggest that stormwater pollution from urban areas can have a substantial effect on the life cycle impacts of some systems (construction materials), while for some systems the effect is small (e.g. electricity generation). However, it is not possible to determine a priori which systems are affected so that the impacts from stormwater pollution should be considered routinely in future LCA studies. The paper also proposes ways to incorporate stormwater pollution burdens into the life cycle databases. Copyright © 2018 Elsevier B.V. All rights reserved.

Validity of chase car data used in developing emissions cycles

DOT National Transportation Integrated Search

2000-09-01

Air quality policies, driving cycles and profiles of average driving behavior have been constructed to characterize the driving behavior of the overall fleet in an effort to ensure vehicle compliance. Chase car data and speed-time profiles of in-use ...

A driving cycle for vehicle emissions estimation in the metropolitan area of Mexico City.

PubMed

Schifter, I; Díaz, L; Rodríguez, R; López-Salinas, E

2005-02-01

A driving cycle derived from driving behavior and real traffic conditions in Mexico City (MC) is proposed. Data acquisition was carried out over diverse MC routes, representing travel under congested and uncongested conditions, using the chase-car approach. Thirteen different on-road patterns, including the four main access roads to MC, trips in both directions and different timetables, a total of 108 trips spanning 1044 km were evaluated in this study. The MC cycle lasts 1360 seconds with a distance of 8.8 km and average speed of 23.4 km h(-1). Both maximum speed (73.6 km h(-1)) and maximum acceleration (2.22 km h(-1)s(-1)) are lower than those of the new vehicles certification employed in Mexico ,FTP-75 cycle., that is, the MC cycle exhibits less cruising time and more transient events than the FTP cycle. A total of 30 light duty gasoline vehicles were classified into different technological groups and tested in an FTP-75 and MC driving cycles in order to compare their emission factors A potential concern is that in Mexico manufacturers design vehicles to meet the emission standards in the FTP, but emission levels increase significantly in a more representative cycle of present driving patterns in the Metropolitan Area of Mexico City (MAMC). The use of a more representative cycle during certification testing, would provide an incentive for vehicle manufacturers to design emissions control systems to remain effective during operation modes that are not currently represented in the official test procedures used in the certification process. Based on the results of the study, the use of MC cycle, which better represents current day driving patterns during testing of vehicle fleets in emissions laboratories, would improve the accuracy of emissions factors used in the MAMC emissions inventories.

Linking Nitrogen-Cycling Microbial Communities to Environmental Fluctuations and Biogeochemical Activity in a Large, Urban Estuary: the San Francisco Bay-Delta

NASA Astrophysics Data System (ADS)

Francis, C.

2015-12-01

Nitrogen (N) availability is an important factor controlling productivity and thus carbon cycling in estuaries. The fate of N in estuaries depends on the activities of the microbes that carry out the N-cycle, which in turn depend on factors such as organic matter availability, dissolved inorganic N, salinity, oxygen, and temperature. Key microbial N transformations include nitrification (the aerobic oxidation of ammonia to nitrite and nitrate) and denitrification (the anaerobic reduction of nitrate to dinitrogen gas). While denitrification leads to N loss, nitrification is the only link between reduced N (produced by decomposition) and oxidized N (substrates for N loss processes), and both processes are known to produce nitrous oxide (N2O), a potent greenhouse gas. Understanding controls of N-cycling in the San Francisco Bay-Delta (SFBD)—the largest estuary on the west coast of North America—is particularly important, as this urban estuary is massively polluted with N, even compared to classic "eutrophic" systems. Interestingly, the SFBD has been spared the detrimental consequences of nutrient enrichment, largely due to high suspended sediment concentrations (and thus low light penetration) throughout the water column, combined with high grazing pressure. However, the recent "clearing" of SFBD waters due to a sharp decrease in suspended sediments may significantly alter the ecology of the estuary, by increasing phytoplankton growth. Thus, the SFBD may be losing its historical resilience to eutrophication, and may soon be "high-nutrient, low-chlorophyll" no more. Elucidating the environmental factors affecting the community structure, activity, and functioning of N-cycling microbes in SFBD is crucial for determining how changes in turbidity and productivity will be propagated throughout the ecosystem. While substantial ecological research in the SFBD has focused on phytoplankton and food webs, bacterial and archaeal communities have received far less attention. Using a combination of molecular, biogeochemical, and 'omics' approaches, we have been examining how N-cycling microbial communities throughout the SFBD change in relation to environmental fluctuations—a critical step in understanding how microbial populations drive biogeochemical cycling in this estuary.

DRIVE: Drive-Cycle Rapid Investigation, Visualization, and Evaluation

Science.gov Websites

specialized statistical clustering methods. The duration of these representative drive cycles, which aim to , DRIVE can benefit a variety of users. For example: Fleet managers can use the tool to make educated investment decisions by determining, in advance, the payback period for a given technology. Vehicle

Texas-specific drive cycles and idle emissions rates for using with EPA's MOVES model : final report.

DOT National Transportation Integrated Search

2014-05-01

The U.S. Environmental Protection Agencys (EPA) newest emissions model, MOtor Vehicle : Emission Simulator (MOVES), uses a disaggregate approach that enables the users of the model to create : and use local drive schedules (drive cycles) in order ...

Temporal Dynamics of the Driving Factors of Urban Landscape Change of Addis Ababa During the Past Three Decades.

PubMed

Zewdie, Meskerem; Worku, Hailu; Bantider, Amare

2018-01-01

Mapping and quantifying urban landscape dynamics and the underlying driving factors are crucial for devising appropriate policies, especially in cities of developing countries where the change is rapid. This study analyzed three decades (1984-2014) of land use land cover change of Addis Ababa using Landsat imagery and examined the underlying factors and their temporal dynamics through expert interview using Analytic Hierarchy Process (AHP). Classification results revealed that urban area increased by 50%, while agricultural land and forest decreased by 34 and 16%, respectively. The driving factors operated differently during the pre and post-1991 period. The year 1991 was chosen because it marked government change in the country resulting in policy change. Policy had the highest influence during the pre-1991 period. Land use change in this period was associated with the housing sector as policies and institutional setups were permissive to this sector. Population growth and in-migration were also important factors. Economic factors played significant role in the post-1991 period. The fact that urban land has a market value, the growth of private investment, and the speculated property market were among the economic factors. Policy reforms since 2003 were also influential to the change. Others such as accessibility, demography, and neighborhood factors were a response to economic factors. All the above-mentioned factors had vital role in shaping the urban pattern of the city. These findings can help planners and policymakers to better understand the dynamic relationship of urban land use and the driving factors to better manage the city.

Temporal Dynamics of the Driving Factors of Urban Landscape Change of Addis Ababa During the Past Three Decades

NASA Astrophysics Data System (ADS)

Zewdie, Meskerem; Worku, Hailu; Bantider, Amare

2018-01-01

Mapping and quantifying urban landscape dynamics and the underlying driving factors are crucial for devising appropriate policies, especially in cities of developing countries where the change is rapid. This study analyzed three decades (1984-2014) of land use land cover change of Addis Ababa using Landsat imagery and examined the underlying factors and their temporal dynamics through expert interview using Analytic Hierarchy Process (AHP). Classification results revealed that urban area increased by 50%, while agricultural land and forest decreased by 34 and 16%, respectively. The driving factors operated differently during the pre and post-1991 period. The year 1991 was chosen because it marked government change in the country resulting in policy change. Policy had the highest influence during the pre-1991 period. Land use change in this period was associated with the housing sector as policies and institutional setups were permissive to this sector. Population growth and in-migration were also important factors. Economic factors played significant role in the post-1991 period. The fact that urban land has a market value, the growth of private investment, and the speculated property market were among the economic factors. Policy reforms since 2003 were also influential to the change. Others such as accessibility, demography, and neighborhood factors were a response to economic factors. All the above-mentioned factors had vital role in shaping the urban pattern of the city. These findings can help planners and policymakers to better understand the dynamic relationship of urban land use and the driving factors to better manage the city.

Overcoming urban GPS navigation challenges through the use of MEMS inertial sensors and proper verification of navigation system performance

NASA Astrophysics Data System (ADS)

Vinande, Eric T.

This research proposes several means to overcome challenges in the urban environment to ground vehicle global positioning system (GPS) receiver navigation performance through the integration of external sensor information. The effects of narrowband radio frequency interference and signal attenuation, both common in the urban environment, are examined with respect to receiver signal tracking processes. Low-cost microelectromechanical systems (MEMS) inertial sensors, suitable for the consumer market, are the focus of receiver augmentation as they provide an independent measure of motion and are independent of vehicle systems. A method for estimating the mounting angles of an inertial sensor cluster utilizing typical urban driving maneuvers is developed and is able to provide angular measurements within two degrees of truth. The integration of GPS and MEMS inertial sensors is developed utilizing a full state navigation filter. Appropriate statistical methods are developed to evaluate the urban environment navigation improvement due to the addition of MEMS inertial sensors. A receiver evaluation metric that combines accuracy, availability, and maximum error measurements is presented and evaluated over several drive tests. Following a description of proper drive test techniques, record and playback systems are evaluated as the optimal way of testing multiple receivers and/or integrated navigation systems in the urban environment as they simplify vehicle testing requirements.

The urban harvest approach as framework and planning tool for improved water and resource cycles.

PubMed

Leusbrock, I; Nanninga, T A; Lieberg, K; Agudelo-Vera, C M; Keesman, K J; Zeeman, G; Rijnaarts, H H M

2015-01-01

Water and resource availability in sufficient quantity and quality for anthropogenic needs represents one of the main challenges in the coming decades. To prepare for upcoming challenges such as increased urbanization and climate change related consequences, innovative and improved resource management concepts are indispensable. In recent years we have developed and applied the urban harvest approach (UHA). The UHA aims to model and quantify the urban water cycle on different temporal and spatial scales. This approach allowed us to quantify the impact of the implementation of water saving measures and new water treatment concepts in cities. In this paper we will introduce the UHA and its application for urban water cycles. Furthermore, we will show first results for an extension to energy cycles and highlight future research items (e.g. nutrients, water-energy-nexus).

Urbanization drives the evolution of parallel clines in plant populations

PubMed Central

Renaudin, Marie; Johnson, Marc T. J.

2016-01-01

Urban ecosystems are an increasingly dominant feature of terrestrial landscapes. While evidence that species can adapt to urban environments is accumulating, the mechanisms through which urbanization imposes natural selection on populations are poorly understood. The identification of adaptive phenotypic changes (i.e. clines) along urbanization gradients would facilitate our understanding of the selective factors driving adaptation in cities. Here, we test for phenotypic clines in urban ecosystems by sampling the frequency of a Mendelian-inherited trait—cyanogenesis—in white clover (Trifolium repens L.) populations along urbanization gradients in four cities. Cyanogenesis protects plants from herbivores, but reduces tolerance to freezing temperatures. We found that the frequency of cyanogenic plants within populations decreased towards the urban centre in three of four cities. A field experiment indicated that spatial variation in herbivory is unlikely to explain these clines. Rather, colder minimum winter ground temperatures in urban areas compared with non-urban areas, caused by reduced snow cover in cities, may select against cyanogenesis. In the city with no cline, high snow cover might protect plants from freezing damage in the city centre. Our study suggests that populations are adapting to urbanization gradients, but regional climatic patterns may ultimately determine whether adaptation occurs. PMID:28003451

Urbanization drives the evolution of parallel clines in plant populations.

PubMed

Thompson, Ken A; Renaudin, Marie; Johnson, Marc T J

2016-12-28

Urban ecosystems are an increasingly dominant feature of terrestrial landscapes. While evidence that species can adapt to urban environments is accumulating, the mechanisms through which urbanization imposes natural selection on populations are poorly understood. The identification of adaptive phenotypic changes (i.e. clines) along urbanization gradients would facilitate our understanding of the selective factors driving adaptation in cities. Here, we test for phenotypic clines in urban ecosystems by sampling the frequency of a Mendelian-inherited trait-cyanogenesis-in white clover (Trifolium repens L.) populations along urbanization gradients in four cities. Cyanogenesis protects plants from herbivores, but reduces tolerance to freezing temperatures. We found that the frequency of cyanogenic plants within populations decreased towards the urban centre in three of four cities. A field experiment indicated that spatial variation in herbivory is unlikely to explain these clines. Rather, colder minimum winter ground temperatures in urban areas compared with non-urban areas, caused by reduced snow cover in cities, may select against cyanogenesis. In the city with no cline, high snow cover might protect plants from freezing damage in the city centre. Our study suggests that populations are adapting to urbanization gradients, but regional climatic patterns may ultimately determine whether adaptation occurs. © 2016 The Author(s).

Condition Monitoring of Urban Infrastructure : Effects of Ground Movement on Adjacent Structures

DOT National Transportation Integrated Search

2012-09-26

Economic considerations drive the more effective use of space in urban areas, promoting the construction of taller buildings with deeper basement structures. The crowded nature of urban environments imposes strict restrictions to the tolerable perfor...

40 CFR 600.109-08 - EPA driving cycles.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false EPA driving cycles. 600.109-08 Section 600.109-08 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL... Emission Regulations for 1978 and Later Model Year Automobiles-Test Procedures § 600.109-08 EPA driving...

40 CFR 600.109-78 - EPA driving cycles.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false EPA driving cycles. 600.109-78 Section 600.109-78 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL... Emission Regulations for 1978 and Later Model Year Automobiles-Test Procedures § 600.109-78 EPA driving...

Urbanization and the Carbon Cycle: Synthesis of Ongoing Research

NASA Astrophysics Data System (ADS)

Gurney, K. R.; Duren, R. M.; Hutyra, L.; Ehleringer, J. R.; Patarasuk, R.; Song, Y.; Huang, J.; Davis, K.; Kort, E. A.; Shepson, P. B.; Turnbull, J. C.; Lauvaux, T.; Rao, P.; Eldering, A.; Miller, C. E.; Wofsy, S.; McKain, K.; Mendoza, D. L.; Lin, J. C.; Sweeney, C.; Miles, N. L.; Richardson, S.; Cambaliza, M. O. L.

2015-12-01

Given the explosive growth in urbanization and its dominant role in current and future global greenhouse gas emissions, urban areas have received increasing research attention from the carbon cycle science community. The emerging focus is driven by the increasingly dense atmospheric observing capabilities - ground and space-based - in addition to the rising profile of cities within international climate change policymaking. Dominated by anthropogenic emissions, urban carbon cycle research requires a cross-disciplinary perspective with contributions from disciplines such as engineering, economics, social theory, and atmospheric science. We review the recent results from a sample of the active urban carbon research efforts including the INFLUX experiment (Indianapolis), the Megacity carbon project (Los Angeles), Salt Lake City, and Boston. Each of these efforts represent unique approaches in pursuit of different scientific and policy questions and assist in setting priorities for future research. From top-down atmospheric measurement systems to bottom-up estimation, these research efforts offer a view of the challenges and opportunities in urban carbon cycle research.

On-road emission characteristics of CNG-fueled bi-fuel taxis

NASA Astrophysics Data System (ADS)

Yao, Zhiliang; Cao, Xinyue; Shen, Xianbao; Zhang, Yingzhi; Wang, Xintong; He, Kebin

2014-09-01

To alleviate air pollution and lessen the petroleum demand from the motor vehicle sector in China, natural gas vehicles (NGVs) have been rapidly developed over the last several years. However, the understanding of the real-world emissions of NGVs is very limited. In this study, the emissions from 20 compressed-natural-gas-fueled bi-fuel taxis were measured using a portable emission measurement system (PEMS) under actual driving conditions in Yichang, China. The emission characteristics of the tested vehicles were analyzed, revealing that the average CO2, CO, HC and NOx emissions from the tested compressed-natural-gas (CNG) taxis under urban driving conditions were 1.6, 4.0, 2.0 and 0.98 times those under highway road conditions, respectively. The CO, HC and NOx emissions from Euro 3 CNG vehicles were approximately 40%, 55% and 44% lower than those from Euro 2 vehicles, respectively. Compared with the values for light-duty gasoline vehicles reported in the literature, the CO2 and CO emissions from the tested CNG taxis were clearly lower; however, significant increases in the HC and NOx emissions were observed. Finally, we normalized the emissions under the actual driving cycles of the entire test route to the New European Driving Cycle (NEDC)-based emissions using a VSP modes method developed by North Carolina State University. The simulated NEDC-based CO emissions from the tested CNG taxis were better than the corresponding emissions standards, whereas the simulated NEDC-based HC and NOx emissions greatly exceeded the standards. Thus, more attention should be paid to the emissions from CNG vehicles. As for the CNG-fueled bi-fuel taxis currently in use, the department of environmental protection should strengthen their inspection and supervision to reduce the emissions from these vehicles. The results of this study will be helpful in understanding and controlling emissions from CNG-fueled bi-fuel vehicles in China.

Older Americans' patterns of driving and using other transportation

DOT National Transportation Integrated Search

2000-09-01

This article examines rural-urban patterns and trends in driving, older people's use of other modes of transportation, and the quality of life consequences of driving versus using other transportation. It is expected that between 1995 and 2025, the U...

Development of a nickel/metal hydride battery (Ni/MH) system for EV application

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

Ikoma, M.; Hamada, S.; Morishita, N.

1994-12-31

In order to satisfy basic battery characteristics for electric vehicles (EV) such as specific energy, specific power and cycle life that are required for driving on urban streets, the authors have selected the valve-regulated lead acid battery as a conventional battery and the nickel/metal-hydride battery as an advanced battery, and have been studying their development in order to put them into practical use by 1998. Regarding the nickel/metal-hydride battery, excellent nickel positive electrode with high temperature charge efficiency accomplished with additives such as Ca compounds, and an exceedingly good hydrogen absorbing alloy negative electrode with high capacity and long cyclemore » life, achieved by adjustment of alloy composition, surface treatment, and control of binder and conductive additive have been developed to overcome difficulties in the scale-up of battery size. Modular batteries using this technology possess specific energy twice (70 Wh/kg) that of the lead-acid battery, and have superior specific power (160 Wh/kg) and cycle life. 5 refs.« less

Drive Cycle Analysis, Measurement of Emissions and Fuel Consumption of a PHEV School Bus: Preprint

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

Barnitt, R.; Gonder, J.

The National Renewable Energy Laboratory (NREL) collected and analyzed real-world school bus drive cycle data and selected similar standard drive cycles for testing on a chassis dynamometer. NREL tested a first-generation plug-in hybrid electric vehicle (PHEV) school bus equipped with a 6.4L engine and an Enova PHEV drive system comprising a 25-kW/80 kW (continuous/peak) motor and a 370-volt lithium ion battery pack. A Bluebird 7.2L conventional school bus was also tested. Both vehicles were tested over three different drive cycles to capture a range of driving activity. PHEV fuel savings in charge-depleting (CD) mode ranged from slightly more than 30%more » to a little over 50%. However, the larger fuel savings lasted over a shorter driving distance, as the fully charged PHEV school bus would initially operate in CD mode for some distance, then in a transitional mode, and finally in a charge-sustaining (CS) mode for continued driving. The test results indicate that a PHEV school bus can achieve significant fuel savings during CD operation relative to a conventional bus. In CS mode, the tested bus showed small fuel savings and somewhat higher nitrogen oxide (NOx) emissions than the baseline comparison bus.« less

Sleepless in Town – Drivers of the Temporal Shift in Dawn Song in Urban European Blackbirds

PubMed Central

Nordt, Anja; Klenke, Reinhard

2013-01-01

Organisms living in urban environments are exposed to different environmental conditions compared to their rural conspecifics. Especially anthropogenic noise and artificial night light are closely linked to urbanization and pose new challenges to urban species. Songbirds are particularly affected by these factors, because they rely on the spread of acoustic information and adjust their behaviour to the rhythm of night and day, e.g. time their dawn song according to changing light intensities. Our aim was to clarify the specific contributions of artificial night light and traffic noise on the timing of dawn song of urban European Blackbirds (Turdus merula). We investigated the onset of blackbird dawn song along a steep urban gradient ranging from an urban forest to the city centre of Leipzig, Germany. This gradient of anthropogenic noise and artificial night light was reflected in the timing of dawn song. In the city centre, blackbirds started their dawn song up to 5 hours earlier compared to those in semi-natural habitats. We found traffic noise to be the driving factor of the shift of dawn song into true night, although it was not completely separable from the effects of ambient night light. We additionally included meteorological conditions into the analysis and found an effect on the song onset. Cloudy and cold weather delayed the onset, but cloud cover was assumed to reflect night light emissions, thus, amplified sky luminance and increased the effect of artificial night light. Beside these temporal effects, we also found differences in the spatial autocorrelation of dawn song onset showing a much higher variability in noisy city areas than in rural parks and forests. These findings indicate that urban hazards such as ambient noise and light pollution show a manifold interference with naturally evolved cycles and have significant effects on the activity patterns of urban blackbirds. PMID:23940759

Time-resolved characterization of primary and secondary particle emissions of a modern gasoline passenger car

NASA Astrophysics Data System (ADS)

Karjalainen, P.; Timonen, H.; Saukko, E.; Kuuluvainen, H.; Saarikoski, S.; Aakko-Saksa, P.; Murtonen, T.; Dal Maso, M.; Ahlberg, E.; Svenningsson, B.; Brune, W. H.; Hillamo, R.; Keskinen, J.; Rönkkö, T.

2015-11-01

Changes in traffic systems and vehicle emission reduction technologies significantly affect traffic-related emissions in urban areas. In many densely populated areas the amount of traffic is increasing, keeping the emission level high or even increasing. To understand the health effects of traffic related emissions, both primary and secondary particles that are formed in the atmosphere from gaseous exhaust emissions need to be characterized. In this study we used a comprehensive set of measurements to characterize both primary and secondary particulate emissions of a modern gasoline passenger car. Our aerosol particle study covers the whole process chain in emission formation, from the engine to the atmosphere, and takes into account also differences in driving patterns. We observed that in mass terms, the amount of secondary particles was 13 times higher than the amount of primary particles. The formation, composition, number, and mass of secondary particles was significantly affected by driving patterns and engine conditions. The highest gaseous and particulate emissions were observed at the beginning of the test cycle when the performance of the engine and the catalyst was below optimal. The key parameter for secondary particle formation was the amount of gaseous hydrocarbons in primary emissions; however, also the primary particle population had an influence. Thus, in order to enhance human health and wellbeing in urban areas, our study strongly indicates that in future legislation, special attention should be directed into the reduction of gaseous hydrocarbons.

THE URBAN STREAM SYNDROME: CURRENT KNOWLEDGE AND THE SEARCH FOR A CURE

EPA Science Inventory

The term "urban stream syndrome" describes the consistently observed ecological degradation of streams draining urban land. This paper reviews recent literature to describe symptoms of the syndrome, explores mechanisms driving the syndrome, and identifies appropriate goals and me...

Urban infrastructure and water management—Science capabilities of the U.S. Geological Survey

USGS Publications Warehouse

Fisher, Shawn C.; Fanelli, Rosemary M.; Selbig, William R.

2016-04-29

Managing the urban-water cycle has increasingly become a challenge for water-resources planners and regulators faced with the problem of providing clean drinking water to urban residents. Sanitary and combined sanitary and storm sewer networks convey wastewater to centralized treatment plants. Impervious surfaces, which include roads, parking lots, and buildings, increase stormwater runoff and the efficiency by which runoff is conveyed to nearby stream channels; therefore, impervious surfaces increase the risk of urban flooding and alteration of natural ecosystems. These challenges will increase with the expansion of urban centers and the probable effects of climate change on precipitation patterns. Understanding the urban-water cycle is critical to effectively manage water resources and to protect people, infrastructure, and urban-stream ecosystems. As a leader in water-supply, wastewater, and stormwater assessments, the U.S. Geological Survey has the expertise and resources needed to monitor, model, and interpret data related to the urban-water cycle and thereby enable water-resources managers to make informed decisions.

Winter climate change effects on soil C and N cycles in urban grasslands.

PubMed

Durán, Jorge; Rodríguez, Alexandra; Morse, Jennifer L; Groffman, Peter M

2013-09-01

Despite growing recognition of the role that cities have in global biogeochemical cycles, urban systems are among the least understood of all ecosystems. Urban grasslands are expanding rapidly along with urbanization, which is expected to increase at unprecedented rates in upcoming decades. The large and increasing area of urban grasslands and their impact on water and air quality justify the need for a better understanding of their biogeochemical cycles. There is also great uncertainty about the effect that climate change, especially changes in winter snow cover, will have on nutrient cycles in urban grasslands. We aimed to evaluate how reduced snow accumulation directly affects winter soil frost dynamics, and indirectly greenhouse gas fluxes and the processing of carbon (C) and nitrogen (N) during the subsequent growing season in northern urban grasslands. Both artificial and natural snow reduction increased winter soil frost, affecting winter microbial C and N processing, accelerating C and N cycles and increasing soil : atmosphere greenhouse gas exchange during the subsequent growing season. With lower snow accumulations that are predicted with climate change, we found decreases in N retention in these ecosystems, and increases in N2 O and CO2 flux to the atmosphere, significantly increasing the global warming potential of urban grasslands. Our results suggest that the environmental impacts of these rapidly expanding ecosystems are likely to increase as climate change brings milder winters and more extensive soil frost. © 2013 John Wiley & Sons Ltd.

An improved fault-tolerant control scheme for PWM inverter-fed induction motor-based EVs.

PubMed

Tabbache, Bekheïra; Benbouzid, Mohamed; Kheloui, Abdelaziz; Bourgeot, Jean-Matthieu; Mamoune, Abdeslam

2013-11-01

This paper proposes an improved fault-tolerant control scheme for PWM inverter-fed induction motor-based electric vehicles. The proposed strategy deals with power switch (IGBTs) failures mitigation within a reconfigurable induction motor control. To increase the vehicle powertrain reliability regarding IGBT open-circuit failures, 4-wire and 4-leg PWM inverter topologies are investigated and their performances discussed in a vehicle context. The proposed fault-tolerant topologies require only minimum hardware modifications to the conventional off-the-shelf six-switch three-phase drive, mitigating the IGBTs failures by specific inverter control. Indeed, the two topologies exploit the induction motor neutral accessibility for fault-tolerant purposes. The 4-wire topology uses then classical hysteresis controllers to account for the IGBT failures. The 4-leg topology, meanwhile, uses a specific 3D space vector PWM to handle vehicle requirements in terms of size (DC bus capacitors) and cost (IGBTs number). Experiments on an induction motor drive and simulations on an electric vehicle are carried-out using a European urban driving cycle to show that the proposed fault-tolerant control approach is effective and provides a simple configuration with high performance in terms of speed and torque responses. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

Effects of diesel/biodiesel blends on regulated and unregulated pollutants from a passenger vehicle operated over the European and the Athens driving cycles

NASA Astrophysics Data System (ADS)

Karavalakis, George; Stournas, Stamoulis; Bakeas, Evangelos

This paper presents the regulated and unregulated exhaust emissions of a diesel passenger vehicle, operated with low sulphur automotive diesel and soy methyl ester blends. Emission and fuel consumption measurements were conducted under real driving conditions (Athens Driving Cycle, ADC) and compared with those of a modified New European Driving Cycle (NEDC) using a chassis dynamometer. A Euro II compliant diesel vehicle was used in this study, equipped with an indirect injection diesel engine, fuelled with diesel fuel and biodiesel blends at proportions of 5, 10, and 20% respectively. Unregulated emissions of 11 polycyclic aromatic hydrocarbons (PAHs), 5 nitro-PAHs, 13 carbonyl compounds (CBCs) and the soluble organic fraction (SOF) of the particulate matter were measured. Qualitative hydrocarbon analysis was also performed on the SOF. Regulated emissions of NO x, CO, HC, CO 2, and PM were also measured over the two test cycles. It was established that some of the emissions measured over the (hot-start) NEDC differed from the real-world cycle. Significant differences were also observed in the vehicle's fuel consumption between the two test cycles. The addition of biodiesel reduced the regulated emissions of CO, HC and PM, while an increase in NO x was observed over the ADC. Carbonyl emissions, PAHs and nitro-PAHs were reduced with the addition of biodiesel over both driving cycles.

40 CFR 1066.801 - Applicability and general provisions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... emission effects from aggressive driving and operation with the vehicle's air conditioner. The SFTP is... driving schedule represents about 3.6 miles of urban driving with the air conditioner operating; and the.... 1066.801 Section 1066.801 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR...

Transportation Energy Futures (TEF) Data and Sources

Science.gov Websites

|agency|4-d|gis|geographic information systems?|municipal|neighborhood|urban density|municipal |carsharing|marketing|real-time|traffic information|eco-driving|idle)$ ^(vmt|vehicle miles traveled|reduction drive|eco-driving|congestion|commute|telework|alternative work|parking|real-time|traffic information

Accounting for the Variation of Driver Aggression in the Simulation of Conventional and Advanced Vehicles

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

Neubauer, J.; Wood, E.

2013-01-01

Hybrid electric vehicles, plug-in hybrid electric vehicles, and battery electric vehicles offer the potential to reduce both oil imports and greenhouse gases, as well as to offer a financial benefit to the driver. However, assessing these potential benefits is complicated by several factors, including the driving habits of the operator. We focus on driver aggression, i.e., the level of acceleration and velocity characteristic of travel, to (1) assess its variation within large, real-world drive datasets, (2) quantify its effect on both vehicle efficiency and economics for multiple vehicle types, (3) compare these results to those of standard drive cycles commonlymore » used in the industry, and (4) create a representative drive cycle for future analyses where standard drive cycles are lacking.« less

Carbon corrosion in PEM fuel cells during drive cycle operation

DOE PAGES

Borup, Rodney L.; Papadias, D. D.; Mukundan, Rangachary; ...

2015-09-14

One of the major contributors to degradation involves the electrocatalyst, including the corrosion of the carbons used as catalyst supports, which leads to changes in the catalyst layer structure. We have measured and quantified carbon corrosion during drive cycle operation and as a variation of the upper and lower potential limits used during drive cycle operation. The amount of carbon corrosion is exacerbated by the voltage cycling inherent in the drive cycle compared with constant potential operation. The potential gap between upper and lower potentials appears to be more important than the absolute operating potentials in the normal operating potentialmore » regime (0.40V to 0.95V) as changes in the measured carbon corrosion are similar when the upper potential was lower compared to raising the lower potential. Catalyst layer thinning was observed during the simulated drive cycle operation which had an associated decrease in catalyst layer porosity. This catalyst layer thinning is not due solely to carbon corrosion, although carbon corrosion likely plays a role; much of this thinning must be from compaction of the material in the catalyst layer. As a result, the decrease in catalyst layer porosity leads to additional performance losses due to mass transport losses.« less

Comparison between motorcyclist’ violation behavior and accidents in urban and rural area in Indonesia: A comparative study

NASA Astrophysics Data System (ADS)

Rahmawati, N.; Widyanti, A.

2017-12-01

Some studies stated that the main factor related to the accident was driving behavior. This study aims to explore the differences between motorcyclist” behaviour and repetitive violation behaviour in two different area, urban and rural area in Indonesia. Respondents were selected based on convenience sampling method in Bandung as a representative of urban area and Kulon Progo as a representative of rural area. They were asked to fill in a questionnaire about driving behaviour, consists of 10 dimensions or 51 questions with Likert scales ranging from 1 (very often) to 6 (never). The results of this study shows that the motorcyclists’ behavior differ significantly between rural and urban area. Motorcyclists in the urban area (Bandung) are more committed to violations than in rural area (Kulon Progo). This result is not in line with previous studies in Australia and United States which stated that motorcyclists in rural area more frequently speeding than in urban area. Implications of the result are discussed.

Development of a KT driving cycle for UMT PHEV powertrain

NASA Astrophysics Data System (ADS)

Atiq, W. H.; Haezah, M. N.; Norbakyah, J. S.; Salisa, A. R.

2015-12-01

Driving cycles were identified as one of the core sources that contribute to develop the powertrain for vehicle. Plug-in hybrid electric vehicles (PHEVs) are the future transport for next generation. Compared to conventional internal combustion engine vehicle, hybrid and electric vehicle can improve fuel economy and reduce green house gases. This paper describes a development of Kuala Terengganu driving cycle for Universiti Malaysia Terengganu PHEV. Car speed-time data along the two selected fixed route is obtained by using on-board technique which is Global Positioning System, GPS. The developed driving cycle contains a 1050s speed time series, with a distance of 2.17 km, and an average and a maximum speed of 20.67 km/h and 61.47 km/h, respectively. The results obtained from this analysis are within reasonable range and satisfactory.

A cycle timer for testing electric vehicles

NASA Technical Reports Server (NTRS)

Soltis, R. F.

1978-01-01

A cycle timer was developed to assist the driver of an electric vehicle in more accurately following and repeating SAE driving schedules. These schedules require operating an electric vehicle in a selected stop-and-go driving cycle and repeating this cycle pattern until the vehicle ceases to meet the requirements of the cycle. The heart of the system is a programmable read-only memory (PROM) that has the required test profiles permanently recorded on plug-in cards, one card for each different driving schedule. The PROM generates a direct current analog signal that drives a speedometer displayed on one scale of a dual movement meter. The second scale of the dual movement meter displays the actual speed of the vehicle as recorded by the fifth wheel. The vehicle operator controls vehicle speed to match the desired profile speed. The PROM controls the recycle start time as well as the buzzer activation. The cycle programmer is powered by the test vehicle's 12-volt accessory battery, through a 5-volt regulator and a 12-volt dc-to-dc converter.

Physical properties of particulate matter (PM) from late model heavy-duty diesel vehicles operating with advanced PM and NO x emission control technologies

NASA Astrophysics Data System (ADS)

Biswas, Subhasis; Hu, Shaohua; Verma, Vishal; Herner, Jorn D.; Robertson, William H.; Ayala, Alberto; Sioutas, Constantinos

Emission control technologies designed to meet the 2007 and 2010 emission standards for heavy-duty diesel vehicles (HDDV) remove effectively the non-volatile fraction of particles, but are comparatively less efficient at controlling the semi-volatile components. A collaborative study between the California Air Resources Board (CARB) and the University of Southern California was initiated to investigate the physicochemical and toxicological characteristics of the semi-volatile and non-volatile particulate matter (PM) fractions from HDDV emissions. This paper reports the physical properties, including size distribution, volatility (in terms of number and mass), surface diameter, and agglomeration of particles emitted from HDDV retrofitted with advanced emission control devices. Four vehicles in combination with six after-treatment devices (V-SCRT ®, Z-SCRT ®, CRT ®, DPX, Hybrid-CCRT ®, EPF) were tested under three driving cycles: steady state (cruise), transient (urban dynamometer driving schedule, UDDS), and idle. An HDDV without any control device is served as the baseline vehicle. Substantial reduction of PM mass emissions (>90%) was accomplished for the HDDV operating with advanced emission control technologies. This reduction was not observed for particle number concentrations under cruise conditions, with the exceptions of the Hybrid-CCRT ® and EPF vehicles, which were efficient in controlling both—mass and number emissions. In general, significant nucleation mode particles (<50 nm) were formed during cruise cycles in comparison with the UDDS cycles, which emit higher PM mass in the accumulation mode. The nucleation mode particles (<50 nm) were mainly internally mixed, and evaporated considerably between 150 and 230 °C. Compared to the baseline vehicle, particles from vehicles with controls (except of the Hybrid-CCRT ®) had a higher mass specific surface area.

Real-time black carbon emission factor measurements from light duty vehicles.

PubMed

Forestieri, Sara D; Collier, Sonya; Kuwayama, Toshihiro; Zhang, Qi; Kleeman, Michael J; Cappa, Christopher D

2013-11-19

Eight light-duty gasoline low emission vehicles (LEV I) were tested on a Chassis dynamometer using the California Unified Cycle (UC) at the Haagen-Smit vehicle test facility at the California Air Resources Board in El Monte, CA during September 2011. The UC includes a cold start phase followed by a hot stabilized running phase. In addition, a light-duty gasoline LEV vehicle and ultralow emission vehicle (ULEV), and a light-duty diesel passenger vehicle and gasoline direct injection (GDI) vehicle were tested on a constant velocity driving cycle. A variety of instruments with response times ≥0.1 Hz were used to characterize how the emissions of the major particulate matter components varied for the LEVs during a typical driving cycle. This study focuses primarily on emissions of black carbon (BC). These measurements allowed for the determination of BC emission factors throughout the driving cycle, providing insights into the temporal variability of BC emission factors during different phases of a typical driving cycle.

Safety reliability evaluation when vehicles turn right from urban major roads onto minor ones based on driver's visual perception.

PubMed

Yu, Bo; Chen, Yuren; Wang, Ruiyun; Dong, Yongjie

2016-10-01

Turning right has a significant impact on urban road traffic safety. Driving into the curve inappropriately or with improper turning speed often leads to a series of potential accidents and hidden dangers. For a long time, the design speed at intersections has been used to determine the physical radius of curbs and channelization, and drivers are expected to drive in accordance with the design speed. However, a large number of real vehicle tests show that for the road without an exclusive right-turn lane, there is not a good correlation between the physical radius of curbs and the turning right speeds. In this paper, shape parameters of the driver's visual lane model are put forward and they have relatively high correlations with right-turn speeds. Hence, an evaluation method about safety reliability of turning right from urban major roads onto minor ones based on driver's visual perception is proposed. For existing roads, the evaluation object could be real driving videos; for those under construction roads, the evaluation object could be visual scenes obtained from a driving simulation device. Findings in this research will make a contribution to the optimization of right-turn design at intersections and lead to the development of auxiliary driving technology. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nitrogen cycling process rates across urban ecosystems.

PubMed

Reisinger, Alexander J; Groffman, Peter M; Rosi-Marshall, Emma J

2016-09-21

Nitrogen (N) pollution of freshwater, estuarine, and marine ecosystems is widespread and has numerous environmental and economic impacts. A portion of this excess N comes from urban watersheds comprised of natural and engineered ecosystems which can alter downstream N export. Studies of urban N cycling have focused on either specific ecosystems or on watershed-scale mass balances. Comparisons of specific N transformations across ecosystems are required to contextualize rates from individual studies. Here we reviewed urban N cycling in terrestrial, aquatic, and engineered ecosystems, and compared N processing in these urban ecosystem types to native reference ecosystems. We found that net N mineralization and net nitrification rates were enhanced in urban forests and riparian zones relative to reference ecosystems. Denitrification was highly variable across urban ecosystem types, but no significant differences were found between urban and reference denitrification rates. When focusing on urban streams, ammonium uptake was more rapid than nitrate uptake in urban streams. Additionally, reduction of stormwater runoff coupled with potential decreases in N concentration suggests that green infrastructure may reduce downstream N export. Despite multiple environmental stressors in urban environments, ecosystems within urban watersheds can process and transform N at rates similar to or higher than reference ecosystems. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A single cyclin–CDK complex is sufficient for both mitotic and meiotic progression in fission yeast

PubMed Central

Gutiérrez-Escribano, Pilar; Nurse, Paul

2015-01-01

The dominant model for eukaryotic cell cycle control proposes that cell cycle progression is driven by a succession of CDK complexes with different substrate specificities. However, in fission yeast it has been shown that a single CDK complex generated by the fusion of the Cdc13 cyclin with the CDK protein Cdc2 can drive the mitotic cell cycle. Meiosis is a modified cell cycle programme in which a single S-phase is followed by two consecutive rounds of chromosome segregation. Here we systematically analyse the requirements of the different fission yeast cyclins for meiotic cell cycle progression. We also show that a single Cdc13–Cdc2 complex, in the absence of the other cyclins, can drive the meiotic cell cycle. We propose that qualitatively different CDK complexes are not absolutely required for cell cycle progression either during mitosis or meiosis, and that a single CDK complex can drive both cell cycle programmes. PMID:25891897

Accounting for the Variation of Driver Aggression in the Simulation of Conventional and Advanced Vehicles: Preprint

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

Neubauer, J.; Wood, E.

2013-03-01

Hybrid electric vehicles, plug-in hybrid electric vehicles, and battery electric vehicles offer the potential to reduce both oil imports and greenhouse gases, as well as to offer a financial benefit to the driver. However, assessing these potential benefits is complicated by several factors, including the driving habits of the operator. We focus on driver aggression, i.e., the level of acceleration and velocity characteristic of travel, to (1) assess its variation within large, real-world drive datasets, (2) quantify its effect on both vehicle efficiency and economics for multiple vehicle types, (3) compare these results to those of standard drive cycles commonlymore » used in the industry, and (4) create a representative drive cycle for future analyses where standard drive cycles are lacking.« less

Twenty-six key research questions in urban stream ecology: an assessment of the state of the science

EPA Science Inventory

Although urban streams have been the focus of much research activity in recent years, there remain many unanswered questions about the mechanisms driving the “urban stream syndrome.” Identification of these key research questions is an important step toward effective, efficient ...

Analysis of Urban-Rural Land-Use Change during 1995-2006 and Its Policy Dimensional Driving Forces in Chongqing, China

PubMed Central

Long, Hualou; Wu, Xiuqin; Wang, Wenjie; Dong, Guihua

2008-01-01

This paper analyzes the urban-rural land-use change of Chongqing and its policy dimensional driving forces from 1995 to 2006, using high-resolution Landsat TM (Thematic Mapper) data of 1995, 2000 and 2006, and socio-economic data from both research institutes and government departments. The outcomes indicated that urban-rural land-use change in Chongqing can be characterized by two major trends: First, the non-agricultural land increased substantially from 1995 to 2006, thus causing agricultural land especially farmland to decrease continuously. Second, the aggregation index of urban settlements and rural settlements shows that local urban-rural development experienced a process of changing from aggregation (1995-2000) to decentralization (2000-2006). Chongqing is a special area getting immersed in many important policies, which include the establishment of the municipality directly under the Central Government, the building of Three Gorges Dam Project, the Western China Development Program and the Grain-for-Green Programme, and bring about tremendous influences on its land-use change. By analyzing Chongqing's land-use change and its policy driving forces, some implications for its new policy of ‘Urban-rural Integrated Reform’ are obtained. That is more attentions need to be paid to curbing excessive and idle rural housing and consolidating rural construction land, and to laying out a scientific land-use plan for its rural areas taking such rural land-use issues as farmland occupation and rural housing land management into accounts, so as to coordinate and balance the urban-rural development. PMID:27879729

Leveraging Big Data Analysis Techniques for U.S. Vocational Vehicle Drive Cycle Characterization, Segmentation, and Development

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

Duran, Adam W; Phillips, Caleb T; Perr-Sauer, Jordan

Under a collaborative interagency agreement between the U.S. Environmental Protection Agency and the U.S. Department of Energy (DOE), the National Renewable Energy Laboratory (NREL) performed a series of in-depth analyses to characterize on-road driving behavior including distributions of vehicle speed, idle time, accelerations and decelerations, and other driving metrics of medium- and heavy-duty vocational vehicles operating within the United States. As part of this effort, NREL researchers segmented U.S. medium- and heavy-duty vocational vehicle driving characteristics into three distinct operating groups or clusters using real-world drive cycle data collected at 1 Hz and stored in NREL's Fleet DNA database. Themore » Fleet DNA database contains millions of miles of historical drive cycle data captured from medium- and heavy-duty vehicles operating across the United States. The data encompass existing DOE activities as well as contributions from valued industry stakeholder participants. For this project, data captured from 913 unique vehicles comprising 16,250 days of operation were drawn from the Fleet DNA database and examined. The Fleet DNA data used as a source for this analysis has been collected from a total of 30 unique fleets/data providers operating across 22 unique geographic locations spread across the United States. This includes locations with topographies ranging from the foothills of Denver, Colorado, to the flats of Miami, Florida. This paper includes the results of the statistical analysis performed by NREL and a discussion and detailed summary of the development of the vocational drive cycle weights and representative transient drive cycles for testing and simulation. Additional discussion of known limitations and potential future work is also included.« less

Limited Evidence for Infection of Urban and Peri-urban Nonhuman Primates with Zika and Chikungunya Viruses in Brazil.

PubMed

Moreira-Soto, Andres; Carneiro, Ianei de Oliveira; Fischer, Carlo; Feldmann, Marie; Kümmerer, Beate M; Silva, Nama Santos; Santos, Uilton Góes; Souza, Breno Frederico de Carvalho Dominguez; Liborio, Fernanda de Azevedo; Valença-Montenegro, Mônica Mafra; Laroque, Plautino de Oliveira; da Fontoura, Fernanda Rosa; Oliveira, Alberto Vinicius Dantas; Drosten, Christian; de Lamballerie, Xavier; Franke, Carlos Roberto; Drexler, Jan Felix

2018-01-01

Chikungunya virus (CHIKV) and Zika virus (ZIKV) emerged in the Americas in 2013. Limited antigenic variability of CHIKV and ZIKV may restrict urban transmission cycles due to population protective immunity. In Africa, sylvatic transmission cycles involving nonhuman primates (NHP) are known for CHIKV and ZIKV, causing cyclic reemergence in humans. To evaluate whether sylvatic cycles can be expected in Latin America, we tested 207 NHP collected between 2012 and 2017 in urban and peri-urban settings in Brazil for infection with ZIKV and CHIKV. No animal tested positive for viral RNA in genus-specific and species-specific reverse transcription-PCR (RT-PCR) assays. In contrast, six animals (2.9%) from the families Atelidae, Callitrichidae, and Cebidae showed ZIKV-specific antibodies and 11 (5.3%) showed CHIKV-specific antibodies in plaque reduction neutralization tests (PRNT). Reactivity was monotypic against either ZIKV or CHIKV in all cases, opposing unspecific virucidal activity of sera. PRNT endpoint titers were low at 1:40 in all NHP, and positive specimens did not correspond to the likely dispersal route and time of introduction of both arboviruses. All antibody-positive samples were therefore tested against the NHP-associated yellow fever virus (YFV) and Mayaro virus (MAYV) and against the human-associated dengue virus (DENV) by PRNT. Two ZIKV-positive samples were simultaneously DENV positive and two CHIKV-positive samples were simultaneously MAYV positive, at titers of 1:40 to 1:160. This suggested cross-reactive antibodies against heterologous alphaviruses and flaviviruses in 24% of ZIKV-positive/CHIKV-positive sera. In sum, low seroprevalence, invariably low antibody titers, and the distribution of positive specimens call into question the capability of ZIKV and CHIKV to infect New World NHP and establish sylvatic transmission cycles. IMPORTANCE Since 2013, Zika virus (ZIKV) and chikungunya virus (CHIKV) have infected millions of people in the Americas via urban transmission cycles. Nonhuman primates (NHP) are involved in sylvatic transmission cycles maintaining ZIKV and CHIKV in the Old World. We tested NHP sampled during 2012 to 2017 in urban and peri-urban areas severely affected by ZIKV and CHIKV in Brazil. Seroprevalence and antibody titers were low for both viruses. Additionally, we found evidence for infection by heterologous viruses eliciting cross-reactive antibodies. Our data suggest that urban or peri-urban NHP are not easily infected by ZIKV and CHIKV despite intense local transmission. These data may imply that the ZIKV and CHIKV outbreaks in the Americas cannot be sustained in urban or peri-urban NHP once human population immunity limits urban transmission cycles. Investigation of diverse animals is urgently required to determine the fate of the ZIKV and CHIKV outbreaks in the Americas.

Limited Evidence for Infection of Urban and Peri-urban Nonhuman Primates with Zika and Chikungunya Viruses in Brazil

PubMed Central

2018-01-01

ABSTRACT Chikungunya virus (CHIKV) and Zika virus (ZIKV) emerged in the Americas in 2013. Limited antigenic variability of CHIKV and ZIKV may restrict urban transmission cycles due to population protective immunity. In Africa, sylvatic transmission cycles involving nonhuman primates (NHP) are known for CHIKV and ZIKV, causing cyclic reemergence in humans. To evaluate whether sylvatic cycles can be expected in Latin America, we tested 207 NHP collected between 2012 and 2017 in urban and peri-urban settings in Brazil for infection with ZIKV and CHIKV. No animal tested positive for viral RNA in genus-specific and species-specific reverse transcription-PCR (RT-PCR) assays. In contrast, six animals (2.9%) from the families Atelidae, Callitrichidae, and Cebidae showed ZIKV-specific antibodies and 11 (5.3%) showed CHIKV-specific antibodies in plaque reduction neutralization tests (PRNT). Reactivity was monotypic against either ZIKV or CHIKV in all cases, opposing unspecific virucidal activity of sera. PRNT endpoint titers were low at 1:40 in all NHP, and positive specimens did not correspond to the likely dispersal route and time of introduction of both arboviruses. All antibody-positive samples were therefore tested against the NHP-associated yellow fever virus (YFV) and Mayaro virus (MAYV) and against the human-associated dengue virus (DENV) by PRNT. Two ZIKV-positive samples were simultaneously DENV positive and two CHIKV-positive samples were simultaneously MAYV positive, at titers of 1:40 to 1:160. This suggested cross-reactive antibodies against heterologous alphaviruses and flaviviruses in 24% of ZIKV-positive/CHIKV-positive sera. In sum, low seroprevalence, invariably low antibody titers, and the distribution of positive specimens call into question the capability of ZIKV and CHIKV to infect New World NHP and establish sylvatic transmission cycles. IMPORTANCE Since 2013, Zika virus (ZIKV) and chikungunya virus (CHIKV) have infected millions of people in the Americas via urban transmission cycles. Nonhuman primates (NHP) are involved in sylvatic transmission cycles maintaining ZIKV and CHIKV in the Old World. We tested NHP sampled during 2012 to 2017 in urban and peri-urban areas severely affected by ZIKV and CHIKV in Brazil. Seroprevalence and antibody titers were low for both viruses. Additionally, we found evidence for infection by heterologous viruses eliciting cross-reactive antibodies. Our data suggest that urban or peri-urban NHP are not easily infected by ZIKV and CHIKV despite intense local transmission. These data may imply that the ZIKV and CHIKV outbreaks in the Americas cannot be sustained in urban or peri-urban NHP once human population immunity limits urban transmission cycles. Investigation of diverse animals is urgently required to determine the fate of the ZIKV and CHIKV outbreaks in the Americas. PMID:29404420

Modeling and predicting urban growth pattern of the Tokyo metropolitan area based on cellular automata

NASA Astrophysics Data System (ADS)

Zhao, Yaolong; Zhao, Junsan; Murayama, Yuji

2008-10-01

The period of high economic growth in Japan which began in the latter half of the 1950s led to a massive migration of population from rural regions to the Tokyo metropolitan area. This phenomenon brought about rapid urban growth and urban structure changes in this area. Purpose of this study is to establish a constrained CA (Cellular Automata) model with GIS (Geographical Information Systems) to simulate urban growth pattern in the Tokyo metropolitan area towards predicting urban form and landscape for the near future. Urban land-use is classified into multi-categories for interpreting the effect of interaction among land-use categories in the spatial process of urban growth. Driving factors of urban growth pattern, such as land condition, railway network, land-use zoning, random perturbation, and neighborhood interaction and so forth, are explored and integrated into this model. These driving factors are calibrated based on exploratory spatial data analysis (ESDA), spatial statistics, logistic regression, and "trial and error" approach. The simulation is assessed at both macro and micro classification levels in three ways: visual approach; fractal dimension; and spatial metrics. Results indicate that this model provides an effective prototype to simulate and predict urban growth pattern of the Tokyo metropolitan area.

Development and Validation of a Slurry Model for Chemical Hydrogen Storage in Fuel Cell Applications

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

Brooks, Kriston P.; Pires, Richard P.; Simmons, Kevin L.

2014-07-25

The US Department of Energy's (DOE) Hydrogen Storage Engineering Center of Excellence (HSECoE) is developing models for hydrogen storage systems for fuel cell-based light duty vehicle applications for a variety of promising materials. These transient models simulate the performance of the storage system for comparison to the DOE’s Technical Targets and a set of four drive cycles. The purpose of this research is to describe the models developed for slurry-based chemical hydrogen storage materials. The storage systems of both a representative exothermic system based on ammonia borane and endothermic system based on alane were developed and modeled in Simulink®. Oncemore » complete the reactor and radiator components of the model were validated with experimental data. The model was then run using a highway cycle, an aggressive cycle, cold-start cycle and hot drive cycle. The system design was adjusted to meet these drive cycles. A sensitivity analysis was then performed to identify the range of material properties where these DOE targets and drive cycles could be met. Materials with a heat of reaction greater than 11 kJ/mol H2 generated and a slurry hydrogen capacity of greater than 11.4% will meet the on-board efficiency and gravimetric capacity targets, respectively.« less

Viscoelastic-coupling model for the earthquake cycle driven from below

USGS Publications Warehouse

Savage, J.C.

2000-01-01

In a linear system the earthquake cycle can be represented as the sum of a solution which reproduces the earthquake cycle itself (viscoelastic-coupling model) and a solution that provides the driving force. We consider two cases, one in which the earthquake cycle is driven by stresses transmitted along the schizosphere and a second in which the cycle is driven from below by stresses transmitted along the upper mantle (i.e., the schizosphere and upper mantle, respectively, act as stress guides in the lithosphere). In both cases the driving stress is attributed to steady motion of the stress guide, and the upper crust is assumed to be elastic. The surface deformation that accumulates during the interseismic interval depends solely upon the earthquake-cycle solution (viscoelastic-coupling model) not upon the driving source solution. Thus geodetic observations of interseismic deformation are insensitive to the source of the driving forces in a linear system. In particular, the suggestion of Bourne et al. [1998] that the deformation that accumulates across a transform fault system in the interseismic interval is a replica of the deformation that accumulates in the upper mantle during the same interval does not appear to be correct for linear systems.

Associations of cycling with urban sprawl and the gasoline price.

PubMed

Rashad, Inas

2009-01-01

Determine the relationships between cycling and urban sprawl and between cycling and the gasoline price. Cross-sectional multivariate regression analyses using pooled data from two individual-level national surveys to analyze the effects of variations in levels of urban sprawl and the gasoline price on cycling as a form of physical activity. Metropolitan areas representative of the U.S. population, 1990 to 2001. Behavioral Risk Factor Surveillance System: 146,730 individuals at least 18-years-old in the United States; Nationwide Personal Transportation Survey: 73,903 individuals at least 18-years-old in the United States. Self-reported information on bicycling served as the dependent variable. Urban sprawl and the gasoline price served as key independent variables. Living in a metropolitan area with a lower degree of urban sprawl increased the probability of cycling in the past month by 3.4 to 4.4 percentage points and 1.6 to 2.1 percentage points from the means for men and women, respectively. Increasing the gasoline price by one dollar increased the probability of cycling by 4.3 to 4.7 percentage points and 2.9 to 3.5 percentage points for men and women, respectively. Results indicate that the prevalence of cycling is higher in less sprawling areas and areas with higher gasoline prices. More research is needed to refine results on how individuals respond to incentives and the roles that monetary and time costs play in improving public health.

Demographic and Geographical Characteristics of Pediatric Trauma in Scotland

DTIC Science & Technology

2013-01-01

the 8-fold Scottish Urban/ Rural Classifi- cation [20], which is based on settlement size and drive time to major conurbations. Social deprivation was...distribution, but with some exceptions. Scotland has an eccentrically distributed population, with 69.5% living in urban areas ( Scottish urban/ rural ...high rate of mortality and prehospital death. Acta Anaesthesiol Scand 2003;47:153-6. [20] Scottish Government: Scottish government urban/ rural

U.S. Forest Service and partners deliver urban wildlife research in support of conservation and management

Treesearch

Susannah B. Lerman; Nancy F. Sonti

2015-01-01

Urban wildlife contributes to the vibrancy of our cities, adds value to the places we live and allows urban residents to connect with nature without driving hours to a protected reserve. Land and water conservation projects have the potential to serve as a refuge for species impacted by urbanization, and in so doing, strengthening the connection between the growing...

On variable hydrostatic transmission for road vehicles, powered by supply of fluid at constant pressure

NASA Technical Reports Server (NTRS)

Magi, M.; Freivald, A.; Andersson, I.; Ericsson, U.

1981-01-01

Various hydrostatic power transmission systems for automotive applications with power supply at constant pressure and unrestricted flow and with a Volvo Flygmotor variable displacement motor as the principal unit were investigated. Two most promising concepts were analyzed in detail and their main components optimized for minimum power loss at the EPA Urban Driving Cycle. The best fuel consumption is less than 10 lit. per 100 kM for a 1542 kG vehicle with a hydrostatic motor and a two speed gear box in series (braking power not recovered). Realistic system pressure affects the fuel consumption just slightly, but the package volume/weight drastically. Back pressure increases losses significantly. Special attention was paid to description of the behavior and modeling of the losses of variable displacement hydrostatic machines.

Teaching and Learning Global Urban Geography: An International Learning-Centred Approach

ERIC Educational Resources Information Center

Kenna, Therese

2017-01-01

The recent drive for the internationalization of curricula, together with calls for the internationalization of the sub-discipline of urban geography beyond the "west", and the growing shift towards learning-centred paradigms in higher education, provided impetus for the design and delivery of an upper level undergraduate urban geography…

What Drives Them to Drive?—Parents' Reasons for Choosing the Car to Take Their Children to School

PubMed Central

Westman, Jessica; Friman, Margareta; Olsson, Lars E.

2017-01-01

Children's school journeys have changed vastly during recent decades: More children are being driven to school in private cars instead of walking and cycling, with many who are entitled to a free school bus service still being driven. Earlier research into travel mode choice has often investigated how urban form impacts upon mode choice regarding school journeys—in particular how urban form hinders or enables the use of the active mode. This paper quantitatively explores parents' stated reasons for choosing the car and the relationship between these reasons and the decision to use the car to take their children to school. We additionally investigate the relationship between sociodemographic factors, distance, and both the stated reasons and the actual mode decision. A sample of 245 parents (194 women) of school children aged 10–15 in the County of Värmland in Sweden were included in the study. The results of PLS-SEM show that the factor Social convenience has a direct relationship with the frequency of car use indicating that the wish to accompany the child and the convenience of car impacts on car choice. If the child is not allowed to travel independently, the parents choose the car to take him/her to school. Sociodemographic factors had a direct relationship with the stated reasons, whereby parents with a higher level of education valued safety/security less. Quite surprisingly, distance (i.e., environmental factor) did not affect car use, indicating that parents drive their children to school regardless of distance. By isolating the particular reasons for choosing the car, this paper focuses on a potentially important missing piece as regards finding out what motivates the increasing car usage in children's school journeys. An increased knowledge of what motivates the decision to take children by car is important for effective policies aimed at changing parents' inclination toward choosing the car. PMID:29167653

Change detection in urban and rural driving scenes: Effects of target type and safety relevance on change blindness.

PubMed

Beanland, Vanessa; Filtness, Ashleigh J; Jeans, Rhiannon

2017-03-01

The ability to detect changes is crucial for safe driving. Previous research has demonstrated that drivers often experience change blindness, which refers to failed or delayed change detection. The current study explored how susceptibility to change blindness varies as a function of the driving environment, type of object changed, and safety relevance of the change. Twenty-six fully-licenced drivers completed a driving-related change detection task. Changes occurred to seven target objects (road signs, cars, motorcycles, traffic lights, pedestrians, animals, or roadside trees) across two environments (urban or rural). The contextual safety relevance of the change was systematically manipulated within each object category, ranging from high safety relevance (i.e., requiring a response by the driver) to low safety relevance (i.e., requiring no response). When viewing rural scenes, compared with urban scenes, participants were significantly faster and more accurate at detecting changes, and were less susceptible to "looked-but-failed-to-see" errors. Interestingly, safety relevance of the change differentially affected performance in urban and rural environments. In urban scenes, participants were more efficient at detecting changes with higher safety relevance, whereas in rural scenes the effect of safety relevance has marginal to no effect on change detection. Finally, even after accounting for safety relevance, change blindness varied significantly between target types. Overall the results suggest that drivers are less susceptible to change blindness for objects that are likely to change or move (e.g., traffic lights vs. road signs), and for moving objects that pose greater danger (e.g., wild animals vs. pedestrians). Copyright © 2017 Elsevier Ltd. All rights reserved.

The South/Southeast Asia Research Initiative (SARI) Update and Meeting Objectives

NASA Technical Reports Server (NTRS)

Vadrevu, Krishna Prasad

2017-01-01

Land Use/Cover Change (LU/CC) is one of the most important types of environmental change in South and Southeast Asian countries. Several studies suggest that LU/CC in these countries is in large part driven by population growth and economic development. In the region, changes that are most common include urban expansion, agricultural land loss, land abandonment, deforestation, logging, reforestation, etc. To address the research needs and priorities in the region, a regional initiative entitled South Southeast Asia Regional Initiative (SARI) has been developed involving US and regional scientists. The initiative is funded by NASA Land Cover, Land Use Change program. The goal of SARI is to integrate state-of-the-art remote sensing, natural sciences, engineering and social sciences to enrich LU/CC science in South Southeast Asian countries. In the presentation, LU/CC change research in SARI countries will be highlighted including the drivers of change. For example, in South Asia, forest cover has been increasing in countries like India, Nepal and Bhutan due to sustainable afforestation measures; whereas, large-scale deforestation in Southeast Asian countries is still continuing, due to oil palm plantation expansion driven by the international market demand in Malaysia and Indonesia. With respect to urbanization, South and Southeast Asian countries contain 23 megacities, each with more than 10 million people. Rapid urbanization is driving agricultural land loss and agricultural intensification has been increasing due to less availability of land for growing food crops such as in India, Vietnam, and Thailand. The drivers of LUCC vary widely in the region and include such factors as land tenure, local economic development, government policies, inappropriate land management, land speculation, improved road networks, etc. In addition, variability in the weather, climate, and socioeconomic factors also drive LU/CC resulting in disruptions of biogeochemical cycles, radiation and the surface energy balance of the atmosphere. The presentation will also highlight SARI collaborative activities with space agencies, universities and non-government organizations including data sharing mechanisms in the region.

Urban Expansion Modeling Approach Based on Multi-Agent System and Cellular Automata

NASA Astrophysics Data System (ADS)

Zeng, Y. N.; Yu, M. M.; Li, S. N.

2018-04-01

Urban expansion is a land-use change process that transforms non-urban land into urban land. This process results in the loss of natural vegetation and increase in impervious surfaces. Urban expansion also alters the hydrologic cycling, atmospheric circulation, and nutrient cycling processes and generates enormous environmental and social impacts. Urban expansion monitoring and modeling are crucial to understanding urban expansion process, mechanism, and its environmental impacts, and predicting urban expansion in future scenarios. Therefore, it is important to study urban expansion monitoring and modeling approaches. We proposed to simulate urban expansion by combining CA and MAS model. The proposed urban expansion model based on MSA and CA was applied to a case study area of Changsha-Zhuzhou-Xiangtan urban agglomeration, China. The results show that this model can capture urban expansion with good adaptability. The Kappa coefficient of the simulation results is 0.75, which indicated that the combination of MAS and CA offered the better simulation result.

Geographic disparities in patient travel for dialysis in the United States.

PubMed

Stephens, J Mark; Brotherton, Samuel; Dunning, Stephan C; Emerson, Larry C; Gilbertson, David T; Harrison, David J; Kochevar, John J; McClellan, Ann C; McClellan, William M; Wan, Shaowei; Gitlin, Matthew

2013-01-01

To estimate travel distance and time for US hemodialysis patients and to compare travel of rural versus urban patients. Dialysis patient residences were estimated from ZIP code-level patient counts as of February 2011 allocated within the ZIP code proportional to census tract-level population, obtained from the 2010 U.S. Census. Dialysis facility addresses were obtained from Medicare public-use files. Patients were assigned to an "original" and "replacement" facility, assuming patients used the facility closest to home and would select the next closest facility as a replacement, if a replacement facility was required. Driving distances and times were calculated between patient residences and facility locations using GIS software. The mean one-way driving distance to the original facility was 7.9 miles; for rural patients average distances were 2.5 times farther than for urban patients (15.9 vs. 6.2 miles). Mean driving distance to a replacement facility was 10.6 miles, with rural patients traveling on average 4 times farther than urban patients to a replacement facility (28.8 vs. 6.8 miles). Rural patients travel much longer distances for dialysis than urban patients. Accessing alternative facilities, if required, would greatly increase rural patient travel, while having little impact on urban patients. Increased travel could have clinical implications as longer travel is associated with increased mortality and decreased quality of life. © 2013 National Rural Health Association.

Natural abundance N stable isotopes in plants and soils as an indicator of N deposition hotspots in urban environments

NASA Astrophysics Data System (ADS)

Trammell, T. L.

2017-12-01

The natural abundance of stable isotopes in plants and soils has been utilized to understand ecological phenomenon. Foliar δ15N is an integrator of soil δ15N, atmospheric N sources, and fractionation processes that occur during plant N uptake, plant N assimilation, and mycorrhizal associations. The amount of reactive N in the environment has greatly increased due to human activities, and urban ecosystems experience excess N deposition that can have cascading effects on plants and soils. Foliar δ15N has been shown to increase with increasing N deposition and nitrification rates suggesting increased foliar δ15N occurs with greater N inputs as a result of accelerated soil N cycling. Thus, foliar δ15N can be an indication of soil N availability for plant uptake and soil N cycling rates, since high N availability results in increased soil N cycling and subsequent loss of 14N. Limited research has utilized foliar and soil δ15N in urban forests to assess the importance of plant uptake of atmospheric N deposition and to gain insight about ecosystem processes. Previous investigations found foliar δ15N of mature trees in urban forests is not only related to elevated pollutant-derived N deposition, but also to soil N availability and soil N cycling rates. Similarly, enriched foliar δ15N of urban saplings was attributed to soil characteristics that indicated higher nitrification, thus, greater nitrate leaching and low N retention in the urban soils. These studies demonstrate the need for measuring the δ15N of various plant and soil N sources while simultaneously measuring soil N processes (e.g., net nitrification rates) in order to use natural abundance δ15N of plants and soils to assess N sources and cycling in urban forests. A conceptual framework that illustrates biogenic and anthropogenic controls on nitrogen isotope composition in urban plants and soils will be presented along with foliar and soil δ15N from urban forests across several cities as a proof of concept. Foliar and soil 15N can be extremely useful when N sources are isotopically distinct, patterns are detectable, or multiple tools are used simultaneously to understand N cycling. N cycles tightly in most ecosystems, thus δ15N in plants and soils can provide information about N source and availability to ecosystems.

Pregnancy risk during menstrual cycle: misconceptions among urban men in India.

PubMed

Verma, Prashant; Singh, Kaushalendra Kumar; Singh, Anjali

2017-06-12

In India, where men take most decisions in the family, it is useful that they have adequate knowledge about pregnancy risks during women's menstrual cycles. Since traditional contraceptive methods are still employed by a large population in India, the knowledge regarding the pregnancy risk during the menstrual cycle is indispensable. This research paper attempts to assess the knowledge among urban men in Uttar Pradesh, India about the fertile window of the menstrual cycle; it also attempts to discover the rationales behind the misconceptions about the concept. This study utilizes the baseline data of the Measurement, Learning, and Evaluation project for the Urban Reproductive Health Initiative in Uttar Pradesh. Descriptive Statistics has been used to assess the prevalence of knowledge among urban men regarding the concept. Using the Discriminant Analysis, we also investigate the rationales behind the misconceptions among urban men about the concept. Only one-fifth of the men have the correct knowledge about the concept. Further, we find that education, societal perception, caste, and spousal discussion about the reproductive issues are the primary factors affecting the knowledge about the pregnancy risk during the menstrual cycle. There is an urgent need for sex education in the region to make the urban men more educated about the reproductive process of women; this may reduce unwanted births and abortion due to an unwanted pregnancy as well. The study promotes the higher education and motivates couples to discuss the reproductive health issues among them. In this manner, we can provide better reproductive health to the women of urban India.

Investigating the impact of static roadside advertising on drivers' situation awareness.

PubMed

Young, Kristie L; Stephens, Amanda N; Logan, David B; Lenné, Michael G

2017-04-01

Roadside advertising has the potential to create a crash risk for drivers as it may distract attention from driving at critical times. In an on-road instrumented vehicle study, we examined if and how static advertising billboards affect drivers' situation awareness across different driving environments. Nineteen fully licensed drivers drove an instrumented vehicle around a 38 km urban test route comprising freeway, busy urban retail and arterial road sections. The route contained a number of static billboards. Drivers provided continuous verbal protocols throughout the drive. Results indicated that the structure and content of drivers' situation awareness was not appreciably affected by the billboards in any of the road environments examined. Drivers focused their attention on the billboards when driving demand was low, such as when driving on the freeway with light to moderate traffic, in lower speed zones, or when stationary. However, when drivers were required to perform a manoeuvre or driving demands increased, drivers directed less attention to the billboards and focussed their awareness on the immediate driving task. This suggests that drivers can, at least under some conditions, effectively self-regulate their attention to billboards when required to focus on the immediate traffic or driving situation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Urbanization and geographic expansion of zoonotic arboviral diseases: mechanisms and potential strategies for prevention.

PubMed

Weaver, Scott C

2013-08-01

Arthropod-borne viruses (arboviruses) mainly infect people via direct spillover from enzootic cycles. However, dengue, chikungunya, and yellow fever viruses have repeatedly initiated urban transmission cycles involving human amplification and peridomestic mosquito vectors to cause major epidemics. Here, I review these urban emergences and potential strategies for their prevention and control. Copyright © 2013 Elsevier Ltd. All rights reserved.

Impact of texting on young drivers' behavior and safety on urban and rural roads through a simulation experiment.

PubMed

Yannis, George; Laiou, Alexandra; Papantoniou, Panagiotis; Christoforou, Charalambos

2014-06-01

This research aims to investigate the impact of texting on the behavior and safety of young drivers on urban and rural roads. A driving simulator experiment was carried out in which 34 young participants drove in different driving scenarios; specifically, driving in good weather, in raining conditions, in daylight and in night were examined. Lognormal regression methods were used to investigate the influence of texting as well as various other parameters on the mean speed and mean reaction time. Binary logistic methods were used to investigate the influence of texting use as well as various other parameters in the probability of an accident. It appears that texting leads to statistically significant decrease of the mean speed and increase of the mean reaction time in urban and rural road environment. Simultaneously, it leads to an increased accident probability due to driver distraction and delayed reaction at the moment of the incident. It appeared that drivers using mobile phones with a touch screen present different driving behavior with respect to their speed, however, they had an even higher probability of being involved in an accident. The analysis of the distracted driving performance of drivers who are texting while driving may allow for the identification of measures for the improvement of driving performance (e.g., restrictive measures, training and licensing, information campaigns). The identification of some of the parameters that have an impact on the behavior and safety of young drivers concerning texting and the consequent results can be exploited by policy decision makers in future efforts for the improvement of road safety. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biomechanical and ergonomic assessment of urban transit operators.

PubMed

Albert, Wayne J; Everson, Donald; Rae, Michelle; Callaghan, Jack P; Croll, Jim; Kuruganti, Usha

2014-01-01

The prevalence of neck and low back musculoskeletal injuries in transit operators has been shown to be high; with work absences exceeding double the National average. There is a lack of biomechanical data generated from field researches to inform on musculoskeletal risk associated with transportation and driving occupations. Instead there has been a reliance on simulated driving and questionnaire-based research. This study was designed to examine the musculoskeletal and biomechanical stresses experienced by urban bus drivers. The main objective was to obtain a baseline understanding of sitting posture, muscle activiation and subjective ratings of stress during regular driving tasks. Fifteen urban city bus drivers were recruited for this study. Bus drivers drove the same 65-minute bus route once, at the same time of day, in the same preselected bus. Wireless surface electromyography monitored muscular activity of the drivers' neck, upper trapezius, and erector spinae and video analysis and seat pressure mapping was used to monitor changes in driving posture. A health and lifestyle questionnaire was administered to record specific neck and back pain experienced by drivers as well as to provide lifestyle habits. Drivers were found to exhibit non-neutral postures for less than 30% of the time while conducting routine tasks of turning and stopping for passenger loading and unloading. The neck posture was the greatest concern in terms of non-neutral posture and this was supported by the higher muscle activation to the neck musculature. There was significant posture adjustment made during the one-hour driving period with the adjustments increasing with driving time. Activities associated with bus driving appear to require the use of non-neutral postures an increase in muscle activation. Significant postural adjustments were needed over the one-hour observation period suggesting that the musculoskeletal demands may increase over a regular 12-hour shift.

Urbanization and environmental change during the economic transition on the Mongolian Plateau: Hohhot and Ulaanbaatar.

PubMed

Fan, Peilei; Chen, Jiquan; John, Ranjeet

2016-01-01

Driven by drastic socioeconomic changes in China and Mongolia, urbanization has become one of the most significant driving forces in the transformation of the Mongolian Plateau in the past 30 years. Using Hohhot and Ulaanbaatar as case studies, we developed a holistic approach to examine the socioeconomic and natural driving forces for urbanization and to investigate the impact on the urban environment. We used a multidisciplinary approach and relied on a variety of data sources to assess the changes of the landscape and environment of the two cities. We detected a rapid urbanization in Hohhot and Ulaanbaatar, both in terms of urban population growth and urban land expansion, from 1990 to 2010, with a much faster speed in 2000-2010. The local geo-physical conditions have constrained the spatial direction of expansion. Ulaanbaatar lagged behind Hohhot for about a decade when measured by indicators of urban population and urban land. Both cities have a degraded urban environment and a growing air pollution epidemic. While Hohhot had worse air pollution than Ulaanbaatar in the early 2000s, the gap between the two cities became smaller after 2010. The research presented here highlights the following as key determinants for urbanization and environmental change: (1) the co-evolution of urbanization, economic development, and environmental change; (2) the urbanization of transitional economies driven by the change of the economic structure, i.e., the development by both manufacturing and tertiary sectors and the change in the primary sector; and (3) the recent institutional changes and increased integration with the global economy. Copyright © 2015 Elsevier Inc. All rights reserved.

Factors driving natural regeneration beneath a planted urban forest

Treesearch

Danica A. Doroski; Alexander J. Felson; Mark A. Bradford; Mark P. Ashton; Emily E. Oldfield; Richard A. Hallett; Sara E. Kuebbing

2018-01-01

Cities around the world are investing in urban forest plantings as a form of green infrastructure. The aim is that these plantations will develop into naturally-regenerating native forest stands. However, woody plant recruitment is often cited as the most limiting factor to creating self-sustaining urban forests. As such, there is interest in site treatments that...

Sensory augmentation for increased awareness of driving environment : final research report.

DOT National Transportation Integrated Search

2016-01-01

The goal of this project was to develop a lateral localization framework for autonomous driving in urban areas. Vehicle location is significant information for the controller, planner and behaviors systems. Lateral location is extremely important for...

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.

Eighteen-Month Final Evaluation of UPS Second Generation Diesel Hybrid-Electric Delivery Vans

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

Lammert, M.; Walkowicz, K.

2012-09-01

A parallel hybrid-electric diesel delivery van propulsion system was evaluated at a UPS facility in Minneapolis using on-vehicle data logging, fueling, and maintenance records. Route and drive cycle analysis showed different duty cycles for hybrid vs. conventional delivery vans; routes were switched between the study groups to provide a valid comparison. The hybrids demonstrated greater advantage on the more urban routes; the initial conventional vans' routes had less dense delivery zones. The fuel economy of the hybrids on the original conventional group?s routes was 10.4 mpg vs. 9.2 mpg for the conventional group on those routes a year earlier. Themore » hybrid group's fuel economy on the original hybrid route assignments was 9.4 mpg vs. 7.9 mpg for the conventional group on those routes a year later. There was no statistically significant difference in total maintenance cost per mile or for the vehicle total cost of operation per mile. Propulsion-related maintenance cost per mile was 77% higher for the hybrids, but only 52% more on a cost-per-delivery-day basis. Laboratory dynamometer testing demonstrated 13%-36% hybrid fuel economy improvement, depending on duty cycle, and up to a 45% improvement in ton-mi/gal. NOx emissions increased 21%-49% for the hybrids in laboratory testing.« less

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.

Research notes : roadway design treatments for rural to urban transitions.

DOT National Transportation Integrated Search

2008-12-01

An ODOT Research study, lead by Karen Dixon at Oregon State University, reviewed research evaluating potential traffic calming strategies for rural-to-urban transitions on high speed highways. Driving simulator evaluations were conducted to assess se...

Climate differentiates forest structure across a residential macrosystem

EPA Science Inventory

The extent of urban ecological homogenization depends on how humans build, inhabit, and manage cities. Morphological and socio-economic facets of neighborhoods can drive the homogenization of forest cover, thus affecting urban ecological and hydrological processes, and ecosystem...

40 CFR 600.109-08 - EPA driving cycles.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 30 2014-07-01 2014-07-01 false EPA driving cycles. 600.109-08 Section 600.109-08 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND GREENHOUSE GAS EXHAUST EMISSIONS OF MOTOR VEHICLES Fuel Economy and Carbon-Related Exhaust...

Improving driving advice provided to cardiology patients on discharge.

PubMed

Vusirikala, Amoolya; Backhouse, Mark; Schimansky, Sarah

2018-01-01

Certain cardiac conditions can limit patients' ability to drive. It remains the doctors' responsibility to advise patients of any driving restrictions and is particularly important after certain diagnoses or procedures. We identified that the quality of documented advice was variable and frequently no written driving advice was recorded on discharge. It was apparent that there was a lack of awareness and knowledge of the current Driving and Vehicle Licensing Agency (DVLA) guidance among junior doctors. We therefore designed a quality improvement project using Plan-Do-Study-Act (PDSA) methodology to improve the provision of driving advice on discharge from a cardiology ward by focusing on staff education. After collecting baseline data, we created a template with cardiology-specific DVLA advice. During the second PDSA cycle, we improved the electronic template and also introduced a hard copy on the ward. During the third PDSA cycle, we incorporated information on DVLA guidance in the specialty induction session. We also evaluated junior doctors' confidence of providing driving advice before and after this intervention. Baseline measurements showed that 10% (9/92) of all discharge summaries included driving advice. This improved to 49% (34/69) after the third PDSA cycle. Importantly, after receiving information on driving advice in the induction, junior doctors felt more confident in providing driving advice to cardiology patients on discharge. In conclusion, the provision of driving advice on discharge is an important element of patient safety. However, clinicians' knowledge and awareness of current DVLA guidance is often limited. We demonstrated a significant increase in the provision of driving advice by introducing a standardised template.

Improving driving advice provided to cardiology patients on discharge

PubMed Central

Vusirikala, Amoolya; Backhouse, Mark; Schimansky, Sarah

2018-01-01

Certain cardiac conditions can limit patients’ ability to drive. It remains the doctors' responsibility to advise patients of any driving restrictions and is particularly important after certain diagnoses or procedures. We identified that the quality of documented advice was variable and frequently no written driving advice was recorded on discharge. It was apparent that there was a lack of awareness and knowledge of the current Driving and Vehicle Licensing Agency (DVLA) guidance among junior doctors. We therefore designed a quality improvement project using Plan–Do–Study–Act (PDSA) methodology to improve the provision of driving advice on discharge from a cardiology ward by focusing on staff education. After collecting baseline data, we created a template with cardiology-specific DVLA advice. During the second PDSA cycle, we improved the electronic template and also introduced a hard copy on the ward. During the third PDSA cycle, we incorporated information on DVLA guidance in the specialty induction session. We also evaluated junior doctors’ confidence of providing driving advice before and after this intervention. Baseline measurements showed that 10% (9/92) of all discharge summaries included driving advice. This improved to 49% (34/69) after the third PDSA cycle. Importantly, after receiving information on driving advice in the induction, junior doctors felt more confident in providing driving advice to cardiology patients on discharge. In conclusion, the provision of driving advice on discharge is an important element of patient safety. However, clinicians’ knowledge and awareness of current DVLA guidance is often limited. We demonstrated a significant increase in the provision of driving advice by introducing a standardised template. PMID:29610769

40 CFR 1066.410 - Dynamometer test procedure.

Code of Federal Regulations, 2014 CFR

2014-07-01

... drive mode. (For purposes of this paragraph (g), the term four-wheel drive includes other multiple drive... Dynamometer test procedure. (a) Dynamometer testing may consist of multiple drive cycles with both cold-start...-setting part identifies the driving schedules and the associated sample intervals, soak periods, engine...

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

EVALUATION OF THE EFFECTIVENESS OF TRUCK EFFICIENCY TECHNOLOGIES IN CLASS 8 TRACTOR-TRAILERS BASED ON A TRACTIVE ENERGY ANALYSIS USING MEASURED DRIVE CYCLE DATA

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

LaClair, Tim J; Gao, Zhiming; Fu, Joshua S.

2014-01-01

Quantifying the fuel savings that can be achieved from different truck fuel efficiency technologies for a fleet s specific usage allows the fleet to select the combination of technologies that will yield the greatest operational efficiency and profitability. This paper presents an analysis of vehicle usage in a commercial vehicle fleet and an assessment of advanced efficiency technologies using an analysis of measured drive cycle data for a class 8 regional commercial shipping fleet. Drive cycle measurements during a period of a full year from six tractor-trailers in normal operations in a less-than-truckload (LTL) carrier were analyzed to develop amore » characteristic drive cycle that is highly representative of the fleet s usage. The vehicle mass was also estimated to account for the variation of loads that the fleet experienced. The drive cycle and mass data were analyzed using a tractive energy analysis to quantify the fuel efficiency and CO2 emissions benefits that can be achieved on class 8 tractor-trailers when using advanced efficiency technologies, either individually or in combination. Although differences exist among class 8 tractor-trailer fleets, this study provides valuable insight into the energy and emissions reduction potential that various technologies can bring in this important trucking application.« less

Analysis of a Temperature-Controlled Exhaust Thermoelectric Generator During a Driving Cycle

NASA Astrophysics Data System (ADS)

Brito, F. P.; Alves, A.; Pires, J. M.; Martins, L. B.; Martins, J.; Oliveira, J.; Teixeira, J.; Goncalves, L. M.; Hall, M. J.

2016-03-01

Thermoelectric generators can be used in automotive exhaust energy recovery. As car engines operate under wide variable loads, it is a challenge to design a system for operating efficiently under these variable conditions. This means being able to avoid excessive thermal dilution under low engine loads and being able to operate under high load, high temperature events without the need to deflect the exhaust gases with bypass systems. The authors have previously proposed a thermoelectric generator (TEG) concept with temperature control based on the operating principle of the variable conductance heat pipe/thermosiphon. This strategy allows the TEG modules’ hot face to work under constant, optimized temperature. The variable engine load will only affect the number of modules exposed to the heat source, not the heat transfer temperature. This prevents module overheating under high engine loads and avoids thermal dilution under low engine loads. The present work assesses the merit of the aforementioned approach by analysing the generator output during driving cycles simulated with an energy model of a light vehicle. For the baseline evaporator and condenser configuration, the driving cycle averaged electrical power outputs were approximately 320 W and 550 W for the type-approval Worldwide harmonized light vehicles test procedure Class 3 driving cycle and for a real-world highway driving cycle, respectively.

Performance Analysis of Hybrid Electric Vehicle over Different Driving Cycles

NASA Astrophysics Data System (ADS)

Panday, Aishwarya; Bansal, Hari Om

2017-02-01

Article aims to find the nature and response of a hybrid vehicle on various standard driving cycles. Road profile parameters play an important role in determining the fuel efficiency. Typical parameters of road profile can be reduced to a useful smaller set using principal component analysis and independent component analysis. Resultant data set obtained after size reduction may result in more appropriate and important parameter cluster. With reduced parameter set fuel economies over various driving cycles, are ranked using TOPSIS and VIKOR multi-criteria decision making methods. The ranking trend is then compared with the fuel economies achieved after driving the vehicle over respective roads. Control strategy responsible for power split is optimized using genetic algorithm. 1RC battery model and modified SOC estimation method are considered for the simulation and improved results compared with the default are obtained.

Effects of land use change and water reuse options on urban water cycle.

PubMed

Lee, Jiho; Pak, Gijung; Yoo, Chulsang; Kim, Sangdan; Yoon, Jaeyoung

2010-01-01

The aim of this article was to study the effects of land use change and water reuse options on an urban water cycle. A water cycle analysis was performed on the Goonja drainage basin, located in metropolitan Seoul, using the Aquacycle model. The chronological effects of urbanization were first assessed for the land uses of the Goonja drainage basin from 1975 to 2005, where the ratio of impervious areas ranged from 43% to 84%. Progressive urbanization was identified as leading to a decrease in evapotranspiration (29%), an increase in surface runoff (41%) and a decrease in groundwater recharge (74%), indicating a serious distortion of the water cycle. From a subsequent analysis of the water reuse options, such as rainwater use and wastewater reuse, it is concluded that wastewater reuse seemed to have an advantage over rainwater use for providing a consistent water supply throughout the year for a country like Korea, where the rainy season is concentrated during the summer monsoon.

The effects of engine operating conditions on CCD chemistry and morphology

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

Yeh, S.W.; Moore, S.M.; Sabourin, E.T.

1996-10-01

The effects of engine driving cycle and engine coolant temperature on combustion chamber deposit (CCD) surface chemistry and morphology were assessed by the use of XPS and scanning electron micrographs. A 3.1L V6 test cell engine was used to generate a six test matrix that compared deposit surface chemistry and morphology under two distinctly different driving cycles, each cycle being evaluated at three separate engine coolant temperatures. Deposit material for each respective test was collected by removable combustion chamber sample probes that were subjected to XPS surface analysis and SEM evaluation. Discernible trends were observed in surface chemistry and depositmore » amounts with respect to changes in both driving cycle and coolant temperature. However, much more pronounced were deposit morphological changes recorded by SEM in different engine coolant temperature regimes for both of the utilized driving cycles. Deposit nodules formed in one temperature regime were seen to be typically much larger in size, highly irregular in shape, and appeared to be porous in structure. At a different operating temperature, the deposit nodules were observed to be extremely uniform and more tightly packed.« less

Patterns and Drivers of Inorganic and Organic Nitrogen and Phosphorus Deposition, Cycling, and Loss Throughout a Metropolitan Area

NASA Astrophysics Data System (ADS)

Decina, S.; Templer, P. H.; Hutyra, L.; Gately, C.

2016-12-01

As the urban population expands to 70% of the global population by the year 2050, it is essential to understand changes in both nitrogen (N) and phosphorus (P) cycling in urban ecosystems. Though rates of atmospheric N deposition have been shown to be elevated in numerous cities, few studies have discerned patterns and drivers of spatial variation within urban areas, nor examined rates of urban P deposition or the organic components of both N and P cycling in these ecosystems. We measured atmospheric inorganic N deposition, soil N cycling and loss, and soil respiration across the greater Boston area in the growing seasons of 2015 and 2016, as well as atmospheric deposition and loss of total (inorganic + organic) N and P in the growing season of 2016. We find that mean rates of inorganic N deposition in the greater Boston area are 8.70 ± 0.68 kg N ha-1 yr-1, which is almost double the rate of N deposition measured at a rural reference site 90 km southwest of Boston. Moreover, rates of N deposition are highly variable, varying from 3.84 to 13.82 kg N ha-1 yr-1 within the greater Boston area. Ammonium (NH4+) deposition composes 69.9 ± 2.2 % of total inorganic N deposition, is highest in late spring, and is strongly correlated with traffic emissions of nitrogen oxides (NOx) and distance to roads, which suggests a strong effect of vehicular ammonia (NH3) emissions and spring fertilizer application on urban N deposition. In contrast to past studies, we do not find significant relationships between rates of atmospheric N deposition with N loss via leaching, nor with rates of soil respiration. These results indicate that studies and networks measuring urban N deposition should make measurements across many sites, urban NH3 emissions should be monitored and modeled to predict and explain the variability in urban N deposition fluxes, and N deposition is decoupled from soil N and C loss in urban areas. Overall, our findings demonstrate that urban areas have distinct patterns and drivers of the biogeochemical cycling of nutrients, particularly N and P.

Effects of alcohol on automated and controlled driving performances.

PubMed

Berthelon, Catherine; Gineyt, Guy

2014-05-01

Alcohol is the most frequently detected substance in fatal automobile crashes, but its precise mode of action is not always clear. The present study was designed to establish the influence of blood alcohol concentration as a function of the complexity of the scenarios. Road scenarios implying automatic or controlled driving performances were manipulated in order to identify which behavioral parameters were deteriorated. A single blind counterbalanced experiment was conducted on a driving simulator. Sixteen experienced drivers (25.3 ± 2.9 years old, 8 men and 8 women) were tested with 0, 0.3, 0.5, and 0.8 g/l of alcohol. Driving scenarios varied: road tracking, car following, and an urban scenario including events inspired by real accidents. Statistical analyses were performed on driving parameters as a function of alcohol level. Automated driving parameters such as standard deviation of lateral position measured with the road tracking and car following scenarios were impaired by alcohol, notably with the highest dose. More controlled parameters such as response time to braking and number of crashes when confronted with specific events (urban scenario) were less affected by the alcohol level. Performance decrement was greater with driving scenarios involving automated processes than with scenarios involving controlled processes.

Effect of Torsional Fastener Resistance on the Lateral Response of a Rail-Tie Structure

DOT National Transportation Integrated Search

1978-09-01

This report describes the results of a Transportation Systems Center investigation conducted under Urban Mass Transportation Administration sponsorship, of the practicality of a flywheel/diesel hybrid power drive for urban transit bus propulsion. The...

Urban Land Use Change Effects on Below and Aboveground Carbon Stocks—a Global Perspective and Future Research Needs

NASA Astrophysics Data System (ADS)

Pouyat, R. V.; Chen, Y.; Yesilonis, I.; Day, S.

2014-12-01

Land use change (LUC) has a significant impact on both above- and below-ground carbon (C) stocks; however, little is known about the net effects of urban LUC on the C cycle and climate system. Moreover, as climate change becomes an increasingly pressing concern, there is growing evidence that urban policy and management decisions can have significant regional impacts on C dynamics. Soil organic carbon (SOC) varies significantly across ecoregions at global and continental scales due to differential sensitivity of primary production, substrate quality, and organic matter decay to changes in temperature and soil moisture. These factors are highly modified by urban LUC due to vegetation removal, soil relocation and disruption, pollution, urban heat island effects, and increased atmospheric CO2 concentrations. As a result, on a global scale urban LUC differentially affects the C cycle from ecoregion to ecoregion. For urban ecosystems, the data collected thus far suggests urbanization can lead to both an increase and decrease in soil C pools and fluxes, depending on the native ecosystem being impacted by urban development. For example, in drier climates, urban landscapes accumulate higher C densities than the native ecosystems they replaced. Results suggest also that soil C storage in urban ecosystems is highly variable with very high (> 20.0) and low (< 2.0) C densities (kg m-2 to a 1 m depth) present in the landscape at any one time. Moreover, similar to non-urban soils, total SOC densities are consistently 2-fold greater than aboveground stocks. For those soils with low SOC densities, there is potential to increase C sequestration through management, but specific urban related management practices need to be evaluated. In addition, urban LUC is a human-driven process and thus can be modified or adjusted to reduce its impacts on the C cycle. For example, policies that influence development patterns, population density, management practices, and other human factors can greatly ameliorate the impact of urban LUC on the C cycle. However, even with the recent and rapid expansion of newly acquired data, the net effects of urban LUC on C stocks and fluxes have not been comprehensively addressed. Furthermore, how sensitive these changes are to urban planning, policy decisions, and site management needs to be explored.

Managing urban nutrient biogeochemistry for sustainable urbanization.

PubMed

Lin, Tao; Gibson, Valerie; Cui, Shenghui; Yu, Chang-Ping; Chen, Shaohua; Ye, Zhilong; Zhu, Yong-Guan

2014-09-01

Urban ecosystems are unique in the sense that human activities are the major drivers of biogeochemical processes. Along with the demographic movement into cities, nutrients flow towards the urban zone (nutrient urbanization), causing the degradation of environmental quality and ecosystem health. In this paper, we summarize the characteristics of nutrient cycling within the urban ecosystem compared to natural ecosystems. The dynamic process of nutrient urbanization is then explored taking Xiamen city, China, as an example to examine the influence of rapid urbanization on food sourced nitrogen and phosphorus metabolism. Subsequently, the concept of a nutrient footprint and calculation method is introduced from a lifecycle perspective. Finally, we propose three system approaches to mend the broken biogeochemical cycling. Our study will contribute to a holistic solution which achieves synergies between environmental quality and food security, by integrating technologies for nutrient recovery and waste reduction. Copyright © 2014 Elsevier Ltd. All rights reserved.

Outlining social physics for modern societies—locating culture, economics, and politics: The Enlightenment reconsidered

PubMed Central

Iberall, A. S.

1985-01-01

A groundwork is laid for a formulation of the modern human social system as a field continuum. As in a simple material physical field, the independent implied relationships of materials or processes in flux have to be based on local conservations of mass, energy, and momentum. In complex fields, the transport fluctuations of momentum are transformed into action modes (e.g., [unk] pdq = ΣHi = H, a characteristic quantum of action over a characteristic cycle time). In complex living systems, a fourth local conservation of population number, the demographic variable, has to be added as a renormalized variable. Modern man, settled in place via agriculture, urbanized, and engaged largely in trade and war, invents a fifth local conservation—value-in-trade, the economic variable. The potentials that drive these five fluxes are also enumerated. Among the more evident external and internal physical-chemical potentials, the driving potentials include a sheaf of internal potential-like components that represent the command-control system emergent as politics. In toto, culture represents the social solvent with the main processes of economics and politics being driven by a social pressure. PMID:16593594

Development & optimization of a rule-based energy management strategy for fuel economy improvement in hybrid electric vehicles

NASA Astrophysics Data System (ADS)

Asfoor, Mostafa

The gradual decline of oil reserves and the increasing demand for energy over the past decades has resulted in automotive manufacturers seeking alternative solutions to reduce the dependency on fossil-based fuels for transportation. A viable technology that enables significant improvements in the overall energy conversion efficiencies is the hybridization of conventional vehicle drive systems. This dissertation builds on prior hybrid powertrain development at the University of Idaho. Advanced vehicle models of a passenger car with a conventional powertrain and three different hybrid powertrain layouts were created using GT-Suite. These different powertrain models were validated against a variety of standard driving cycles. The overall fuel economy, energy consumption, and losses were monitored, and a comprehensive energy analysis was performed to compare energy sources and sinks. The GT-Suite model was then used to predict the formula hybrid SAE vehicle performance. Inputs to this model were a numerically predicted engine performance map, an electric motor torque curve, vehicle geometry, and road load parameters derived from a roll-down test. In this case study, the vehicle had a supervisory controller that followed a rule-based energy management strategy to insure a proper power split during hybrid mode operation. The supervisory controller parameters were optimized using discrete grid optimization method that minimized the total amount of fuel consumed during a specific urban driving cycle with an average speed of approximately 30 [mph]. More than a 15% increase in fuel economy was achieved by adding supervisory control and managing power split. The vehicle configuration without the supervisory controller displayed a fuel economy of 25 [mpg]. With the supervisory controller this rose to 29 [mpg]. Wider applications of this research include hybrid vehicle controller designs that can extend the range and survivability of military combat platforms. Furthermore, the GT-Suite model can be easily accommodated to simulate propulsion systems that store regenerative power when braking, making it available for acceleration and off-road maneuvering.

A Meta-Analysis of Global Urban Land Expansion

PubMed Central

Seto, Karen C.; Fragkias, Michail; Güneralp, Burak; Reilly, Michael K.

2011-01-01

The conversion of Earth's land surface to urban uses is one of the most irreversible human impacts on the global biosphere. It drives the loss of farmland, affects local climate, fragments habitats, and threatens biodiversity. Here we present a meta-analysis of 326 studies that have used remotely sensed images to map urban land conversion. We report a worldwide observed increase in urban land area of 58,000 km2 from 1970 to 2000. India, China, and Africa have experienced the highest rates of urban land expansion, and the largest change in total urban extent has occurred in North America. Across all regions and for all three decades, urban land expansion rates are higher than or equal to urban population growth rates, suggesting that urban growth is becoming more expansive than compact. Annual growth in GDP per capita drives approximately half of the observed urban land expansion in China but only moderately affects urban expansion in India and Africa, where urban land expansion is driven more by urban population growth. In high income countries, rates of urban land expansion are slower and increasingly related to GDP growth. However, in North America, population growth contributes more to urban expansion than it does in Europe. Much of the observed variation in urban expansion was not captured by either population, GDP, or other variables in the model. This suggests that contemporary urban expansion is related to a variety of factors difficult to observe comprehensively at the global level, including international capital flows, the informal economy, land use policy, and generalized transport costs. Using the results from the global model, we develop forecasts for new urban land cover using SRES Scenarios. Our results show that by 2030, global urban land cover will increase between 430,000 km2 and 12,568,000 km2, with an estimate of 1,527,000 km2 more likely. PMID:21876770

10 CFR 474.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

...; PETROLEUM-EQUIVALENT FUEL ECONOMY CALCULATION § 474.2 Definitions. For the purposes of this part, the term: Combined energy consumption value means the weighted average of the Urban Dynamometer Driving Schedule and the Highway Fuel Economy Driving Schedule energy consumption values (weighted 55/45 percent...

10 CFR 474.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

...; PETROLEUM-EQUIVALENT FUEL ECONOMY CALCULATION § 474.2 Definitions. For the purposes of this part, the term: Combined energy consumption value means the weighted average of the Urban Dynamometer Driving Schedule and the Highway Fuel Economy Driving Schedule energy consumption values (weighted 55/45 percent...

10 CFR 474.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

...; PETROLEUM-EQUIVALENT FUEL ECONOMY CALCULATION § 474.2 Definitions. For the purposes of this part, the term: Combined energy consumption value means the weighted average of the Urban Dynamometer Driving Schedule and the Highway Fuel Economy Driving Schedule energy consumption values (weighted 55/45 percent...

Visual search and urban city driving under the influence of marijuana and alcohol

DOT National Transportation Integrated Search

2000-03-01

The purpose of this study was to empirically determine the separate and combined effects of delta-9-tetrahydrocannabinol (THC) and alcohol on visual search and actual city driving performance. On separate evenings, 16 subjects were given weight-calib...

What drives the seasonal pattern of δ13C in the net land-atmosphere CO2 exchange across the United States?

NASA Astrophysics Data System (ADS)

Raczka, B. M.; Dlugokencky, E. J.; Ehleringer, J. R.; Lai, C. T.; Pataki, D. E.; Saleska, S. R.; Torn, M. S.; Vaughn, B. H.; Wehr, R. A.; Bowling, D. R.

2016-12-01

The seasonal pattern of δ13C of atmospheric CO2 depends upon both local and non-local land-atmosphere exchange and atmospheric transport. It has been suggested that the seasonal pattern is driven primarily from local variation in the δ13C of the net CO2 flux (exchange between vegetation and the atmosphere) as a result of variation of stomatal conductance of the vegetation. Here we study local variation of δ13C of the land-atmosphere exchange at 7 sites across the United States representing forests (Harvard, Howland, Niwot Ridge, Wind River), grasslands (Southern Great Plains, Rannell Prairie) and an urban center (Salt Lake City). Using a simple 2-part mixing model with background corrections we find that the δ13C of the net exchange of CO2 was most enriched at the grassland sites (-18.9 o/oo), and most depleted at the urban site (-29.6 o/oo) due to the contribution of C4 photosynthesis and fossil fuel emissions, respectively. The amplitude of the seasonal cycle was most pronounced at the C3/C4 grassland and the urban sites. In contrast, the forested sites have a reduced seasonal cycle, and remain almost constant during the growing season (0.49 o/oo change). Furthermore, by accounting for relatively fast δ13C variations in non-local sources at Niwot Ridge we find that the seasonal pattern in δ13C of net exchange is eliminated altogether. These results support the idea that a coherent, global seasonal pattern in δ13C of net exchange is influenced by seasonal transitions in C3/C4 grass, and the intensity and seasonal timing of fossil fuel emissions. This will have important implications for studies that use δ13C to constrain large-scale carbon fluxes.

[Thermodynamic principles and physiologic criteria for the use of heat engines to drive the ventricles of an artificial heart].

PubMed

Kiselev, Iu M; Mordashev, V M; Osipov, A P; Shumakov, V I

1990-01-01

The authors review the thermodynamic bases and physiological limitations of the applicability of thermal engines for driving artificial heart ventricles. Show that the thermodynamic characteristics of Stirling and Brighton cycles do not make it possible to effectively use cycle-based engines in the artificial heart. A steam engine operating in accordance with the Rankine cycle may be regarded as an optimum type engine for that purpose. Demonstrate that according to the rules of physiology, use should be made of a separate driving of artificial heart ventricles by two independently operating steam engines. Provide the characteristics of the Soviet artificial heart "MIKRON" acceptable for implantation into the orthotopic position.

A study of the health effects of bicycling in an urban atmosphere

DOT National Transportation Integrated Search

1977-10-14

This report analyzes data on the health effects of bicycling in an urban environment through intensive study of ten healthy male subjects bicycling or driving in systematically varied conditions in the streets of Washington, D.C. Evaluation criteria ...

URBAN MORPHOLOGY FOR HOUSTON TO DRIVE MODELS-3/CMAQ AT NEIGHBORHOOD SCALES

EPA Science Inventory

Air quality simulation models applied at various horizontal scales require different degrees of treatment in the specifications of the underlying surfaces. As we model neighborhood scales ( 1 km horizontal grid spacing), the representation of urban morphological structures (e....

Is Diet Flexibility an Adaptive Life Trait for Relictual and Peri-Urban Populations of the Endangered Primate Macaca sylvanus?

PubMed Central

Maibeche, Yasmina; Moali, Aissa; Yahi, Nassima; Menard, Nelly

2015-01-01

Habitat loss, fragmentation and urban expansion may drive some species to marginal habitats while others succeed in exploiting urban areas. Species that show dietary flexibility are more able to take advantage of human activities to supplement their diet with anthropogenically abundant and accessible resources. The Barbary macaque (Macaca sylvanus) is an endangered species due to the loss of its habitat, and human pressure. The population of Gouraya National Park (Algeria) lives in a relictual habitat that constitutes about 0.6% of the species range. In addition, this population is a unique case where urban expansion favours contact zones between Barbary macaque habitats and a big city (Bejaia). We quantified the dietary composition of Gouraya macaques over an annual cycle with the objective to understand how diet flexibility of this species may help it adapt to a relictual habitat or cope with urban expansion. We recorded the phenology of plant species every month. This study shows that Gouraya macaques, compared to those living in other forest types of the distribution area, are under lower seasonal constraints. They consume a greater amount of fruit and seeds that are available throughout much of the year, and a lesser amount of costly to find and extract subterranean foods. Therefore the Gouraya relictual habitat appears as a favourable environment compared to other major habitats of that species. This study also shows that colonizing peri-urban zones increases the availability and species richness of diet resources for Barbary macaques as they consume more human foods and exotic plants than in farther sites. Adult males eat more human foods than adult females and immatures do. The exploitation of high-energy anthropogenic food could favour macaque population growth and expansion towards the city center associated with human/macaque conflicts. We recommend applying management actions to restore macaques back to their natural habitat. PMID:25714476

Effects of upper-limb immobilisation on driving safety.

PubMed

Gregory, J J; Stephens, A N; Steele, N A; Groeger, J A

2009-03-01

Doctors are frequently asked by patients whether it is safe to drive with an upper limb immobilised in a cast. In the literature there are no objective measurements of the effects of upper-limb immobilisation upon driving performance. Eight healthy volunteers performed four 20-min driving circuits in a driving simulator (STISIM 400W), circuits 1 and 4 without immobilisation and circuits 2 and 3 with immobilisation. Immobilisation involved a lightweight below-elbow cast with the thumb left free. Volunteers were randomised to right or left immobilisation for circuit 2, and the contralateral wrist was immobilised for circuit 3. Circuits included urban and rural environments and specific hazards (pedestrians crossing, vehicles emerging from a concealed entrance, traffic lights changing suddenly, avoidance of an oncoming vehicle in the driver's carriageway). Limb immobilisation led to more cautious rural and urban driving, with less adjustment of speed and lateral road position than when unrestricted. However when responding to hazards immobilisation caused less safe driving, with higher speeds, a greater proximity to the hazard before action was taken and less steering adjustment. The effects of restriction upon performance were more prevalent and severe with right-arm immobilisation. Upper-limb immobilisation appears to have little effect on the ability to drive a car unchallenged, but to adversely affect responses to routine hazards. Advice on ability to drive safely should be cautious, as the impact of immobilisation appears to be more subtle and wide ranging than previously thought.

The Effect of Drive Signal Limiting on High Cycle Fatigue Life Analysis

NASA Technical Reports Server (NTRS)

Kihm, Frederic; Rizzi, Stephen A.

2014-01-01

It is common practice to assume a Gaussian distribution of both the input acceleration and the response when modeling random vibration tests. In the laboratory, however, shaker controllers often limit the drive signal to prevent high amplitude peaks. The high amplitudes may either be truncated at a given level (socalled brick wall limiting or abrupt clipping), or compressed (soft limiting), resulting in drive signals which are no longer Gaussian. The paper first introduces several methods for limiting a drive signal, including brick wall limiting and compression. The limited signal is then passed through a linear time-invariant system representing a device under test. High cycle fatigue life predictions are subsequently made using spectral fatigue and rainflow cycle counting schemes. The life predictions are compared with those obtained from unclipped input signals. Some guidelines are provided to help the test engineer decide how clipping should be applied under different test scenarios.

Frequency-chirp rates of harmonics driven by a few-cycle pulse

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

Murakami, M.; Mauritsson, J.; Gaarde, M.B.

2005-08-15

We present numerical calculations of the time-frequency characteristics of cutoff harmonics generated by few-cycle laser pulses. We find that for driving pulses as short as three optical cycles, the adiabatic prediction for the harmonic chirp rate is very accurate. This negative chirp is so large that the resulting bandwidth causes substantial overlap between neighboring harmonics, and the harmonic phase therefore appears to not vary in time or frequency. By adding a compensating positive chirp to the driving pulse, which reduces the harmonic bandwidth and allows for the appearance of the negative chirp, we can measure the harmonic chirp rates. Wemore » also find that the positive chirp on the driving pulse causes the harmonics to shift down in frequency. We show that this counterintuitive result is caused by the change in the strong field continuum dynamics introduced by the variation of the driving frequency with time.« less

Cleansed Data from Transportation Studies and Surveys | Transportation

Science.gov Websites

and search for transportation studies and surveys by name, date, state, agency, survey records, and browse and download all the drive cycle data from different studies, see drive cycle data. Study/Survey Name Year State(s)/Region Data Collection Agency Survey Records Vehicles with Installed GPS

Temperature and Driving Cycle Significantly Affect Carbonaceous Gas and Particle Matter Emissions from Diesel Trucks

EPA Science Inventory

The present study examines the effects of fuel (an ultra-low sulfur diesel [ULSD] versus a 20% v/v soy-based biodiesel—80% v/v petroleum blend [B20]), temperature, load, vehicle, driving cycle, and active regeneration technology on gas- and particle-phase carbon emissions from li...

Drive Cycle Analysis Tool - DriveCAT | NREL

Science.gov Websites

tool was created by NREL's fleet test and evaluation team, which conducts in-service performance their needs. Learn more about NREL's fleet test and evaluation research. Contact Us Let us know if you have any questions about the data, need assistance, or would like to contribute test cycles. We also

Temperature and driving cycle significantly affect semi-volatile organic compound emissions from diesel trucks

EPA Science Inventory

The present study examines the effects of fuel (an ultra-low sulfur diesel [ULSD] versus a 20% v/v soy-based biodiesel—80% v/v petroleum blend [B20]), temperature, load, vehicle, driving cycle, and active regeneration technology on gas- and particle-phase carbon emissions f...

An investigation on the fuel savings potential of hybrid hydraulic refuse collection vehicles.

PubMed

Bender, Frank A; Bosse, Thomas; Sawodny, Oliver

2014-09-01

Refuse trucks play an important role in the waste collection process. Due to their typical driving cycle, these vehicles are characterized by large fuel consumption, which strongly affects the overall waste disposal costs. Hybrid hydraulic refuse vehicles offer an interesting alternative to conventional diesel trucks, because they are able to recuperate, store and reuse braking energy. However, the expected fuel savings can vary strongly depending on the driving cycle and the operational mode. Therefore, in order to assess the possible fuel savings, a typical driving cycle was measured in a conventional vehicle run by the waste authority of the City of Stuttgart, and a dynamical model of the considered vehicle was built up. Based on the measured driving cycle and the vehicle model including the hybrid powertrain components, simulations for both the conventional and the hybrid vehicle were performed. Fuel consumption results that indicate savings of about 20% are presented and analyzed in order to evaluate the benefit of hybrid hydraulic vehicles used for refuse collection. Copyright © 2014 Elsevier Ltd. All rights reserved.

Internet Enabled Remote Driving of a Combat Hybrid Electric Power System for Duty Cycle Measurement

DTIC Science & Technology

2007-06-01

INTERNET ENABLED REMOTE DRIVING OF A COMBAT HYBRID ELECTRIC POWER SYSTEM FOR DUTY CYCLE MEASUREMENT Jarrett Goodell1 Marc Compere , Ph.D.2...Orlando, FL, April 2006. 2. Compere , M.; M.; Goodell, J.; Simon, M; Smith, W.; Brudnak, M, “Robust Control Techniques Enabling Duty Cycle...2006-01-3077, SAE Power Systems Conference, Nov. 2006. 3. Compere , M.; Simon, M.; Kajs, J.; Pozolo, M., “Tracked Vehicle Mobility Load Emulation for a

Online energy management strategy of fuel cell hybrid electric vehicles based on data fusion approach

NASA Astrophysics Data System (ADS)

Zhou, Daming; Al-Durra, Ahmed; Gao, Fei; Ravey, Alexandre; Matraji, Imad; Godoy Simões, Marcelo

2017-10-01

Energy management strategy plays a key role for Fuel Cell Hybrid Electric Vehicles (FCHEVs), it directly affects the efficiency and performance of energy storages in FCHEVs. For example, by using a suitable energy distribution controller, the fuel cell system can be maintained in a high efficiency region and thus saving hydrogen consumption. In this paper, an energy management strategy for online driving cycles is proposed based on a combination of the parameters from three offline optimized fuzzy logic controllers using data fusion approach. The fuzzy logic controllers are respectively optimized for three typical driving scenarios: highway, suburban and city in offline. To classify patterns of online driving cycles, a Probabilistic Support Vector Machine (PSVM) is used to provide probabilistic classification results. Based on the classification results of the online driving cycle, the parameters of each offline optimized fuzzy logic controllers are then fused using Dempster-Shafer (DS) evidence theory, in order to calculate the final parameters for the online fuzzy logic controller. Three experimental validations using Hardware-In-the-Loop (HIL) platform with different-sized FCHEVs have been performed. Experimental comparison results show that, the proposed PSVM-DS based online controller can achieve a relatively stable operation and a higher efficiency of fuel cell system in real driving cycles.

A Driving Cycle Detection Approach Using Map Service API

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

Zhu, Lei; Gonder, Jeffrey D

Following advancements in smartphone and portable global positioning system (GPS) data collection, wearable GPS data have realized extensive use in transportation surveys and studies. The task of detecting driving cycles (driving or car-mode trajectory segments) from wearable GPS data has been the subject of much research. Specifically, distinguishing driving cycles from other motorized trips (such as taking a bus) is the main research problem in this paper. Many mode detection methods only focus on raw GPS speed data while some studies apply additional information, such as geographic information system (GIS) data, to obtain better detection performance. Procuring and maintaining dedicatedmore » road GIS data are costly and not trivial, whereas the technical maturity and broad use of map service application program interface (API) queries offers opportunities for mode detection tasks. The proposed driving cycle detection method takes advantage of map service APIs to obtain high-quality car-mode API route information and uses a trajectory segmentation algorithm to find the best-matched API route. The car-mode API route data combined with the actual route information, including the actual mode information, are used to train a logistic regression machine learning model, which estimates car modes and non-car modes with probability rates. The experimental results show promise for the proposed method's ability to detect vehicle mode accurately.« less

Urbanization in the US: land use trends, impacts on forest area, projections, and policy considerations

Treesearch

Ralph Alig

2010-01-01

Since World War II, socio-economic drivers of US urbanization such as population totals and personal income levels have increased substantially. Human land use is the primary force driving changes in forest ecosystem attributes including forest area, which is the focus of this paper. The percentage of the US population residing in urban areas is higher than that in...

Heavy metal(loid)s and organic contaminants in groundwater in the Pearl River Delta that has undergone three decades of urbanization and industrialization: Distributions, sources, and driving forces.

PubMed

Huang, Guanxing; Zhang, Ming; Liu, Chunyan; Li, Liangping; Chen, Zongyu

2018-09-01

Urbanization and industrialization have increased groundwater resource demands, and may drive the change of heavy metal(loid)s and organic chemicals in groundwater in the Pearl River Delta (PRD), southern China. Thus, a comprehensive understanding of the distributions, sources, and driving forces of heavy metal(loid)s and organic chemicals in groundwater in the PRD is vital for water resource management in this region. In this study, eight heavy metal(loid)s and fifty-five organic chemicals in groundwater across the PRD were investigated. The results show that undrinkable groundwater related to heavy metal(loid)s was mainly due to high concentrations of Fe (19.3%) and As (6.8%). Eighteen organic contaminants were detected in groundwater in the PRD, where the most frequently detected organic contaminant was naphthalene, and its detection rate was 2.51%. In 5.3% of all groundwater samples, one or more organic contaminants were found. All detected organic contaminants, except ones without allowable limits, in groundwater were at concentrations below allowable limits of China. The mean concentrations of heavy metal(loid)s in granular aquifers were higher than those in fissured and karst aquifers, especially for Fe and As. Except Se, the mean concentrations of other heavy metal(loid)s and the frequency of detection of organic contaminants in groundwater in urbanized and peri-urban areas were higher than those in non-urbanized areas, especially for Hg, Co, and organic contaminants. Fe, As, and Se in groundwater mainly originated from the release of Fe/As/Se rich sediments. The former two were driven by reduction reactions, while the latter was driven by oxidation resulting from the infiltration of NO 3 - . In contrast, other five heavy metal(loid)s and organic contaminants in groundwater mainly originated from the anthropogenic sources, such as the infiltration of industrial sewage. It is evident that urbanization and industrialization are two powerful driving forces for heavy metal(loid)s and organic contaminants in groundwater in the PRD. Copyright © 2018 Elsevier B.V. All rights reserved.

Hydraulic Hybrid and Conventional Parcel Delivery Vehicles' Measured Laboratory Fuel Economy on Targeted Drive Cycles

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

Lammert, M. P.; Burton, J.; Sindler, P.

2014-10-01

This research project compares laboratory-measured fuel economy of a medium-duty diesel powered hydraulic hybrid vehicle drivetrain to both a conventional diesel drivetrain and a conventional gasoline drivetrain in a typical commercial parcel delivery application. Vehicles in this study included a model year 2012 Freightliner P100H hybrid compared to a 2012 conventional gasoline P100 and a 2012 conventional diesel parcel delivery van of similar specifications. Drive cycle analysis of 484 days of hybrid parcel delivery van commercial operation from multiple vehicles was used to select three standard laboratory drive cycles as well as to create a custom representative cycle. These fourmore » cycles encompass and bracket the range of real world in-use data observed in Baltimore United Parcel Service operations. The NY Composite cycle, the City Suburban Heavy Vehicle Cycle cycle, and the California Air Resources Board Heavy Heavy-Duty Diesel Truck (HHDDT) cycle as well as a custom Baltimore parcel delivery cycle were tested at the National Renewable Energy Laboratory's Renewable Fuels and Lubricants Laboratory. Fuel consumption was measured and analyzed for all three vehicles. Vehicle laboratory results are compared on the basis of fuel economy. The hydraulic hybrid parcel delivery van demonstrated 19%-52% better fuel economy than the conventional diesel parcel delivery van and 30%-56% better fuel economy than the conventional gasoline parcel delivery van on cycles other than the highway-oriented HHDDT cycle.« less

Urban Impact at the Urban-Agricultural Interface in Madison, WI: an Ecosystem Modeling Approach

NASA Astrophysics Data System (ADS)

Logan, K. E.; Kucharik, C. J.; Schneider, A.

2009-12-01

Global population and the proportion of people living in urban areas both continue to grow while average urban density is decreasing worldwide. Because urban areas are often located in the most agriculturally productive lands, expansion of the built environment can cause sharp reductions in land available for cultivation. Conversion of land to urban use also significantly alters climate variables. Urban materials differ from natural land covers in terms of albedo, thermal properties, and permeability, altering energy and water cycles. Anthropogenic heat emissions also alter the energy balance in and around a city. Preliminary analysis of urban impacts around Madison, WI, a small city located in a thriving agricultural region, was performed using the National Land Cover Database (NLCD), MODIS albedo products, ground-based observations, and a simulation of urban expansion, within a geographic information system (GIS). Population of the county is expected to increase by 58% while urban density is projected to decrease by 49% between 1992 and 2030, reflecting projected worldwide patterns. Carbon stored in the top 25cm of soil was found to be over 2.5 times greater in remnant prairies than in croplands and was calculated to be even less in urban areas; projected urban development may thus lead to large losses in carbon storage. Albedo measurements also show a significant decrease with urban development. Projected urban expansion between 2001 and 2030 is expected to convert enough agricultural lands to urban areas to result in a loss of 247,000 tons of crop yield in Dane County alone, based on current yields. For a more complete analysis of these impacts, urban parameters are incorporated into a terrestrial ecosystem model known as Agro-IBIS. This approach allows for detailed comparison of energy balance and biogeochemical cycles between local crop systems, lawns, and impervious city surfaces. Changes in these important cycles, in soil carbon storage, and in crop productivity/yield for 1992 - 2001 and projected 2030 development around Madison, WI will be shown.

GPS Data Filtration Method for Drive Cycle Analysis Applications

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

Duran, A.; Earleywine, M.

2013-02-01

When employing GPS data acquisition systems to capture vehicle drive-cycle information, a number of errors often appear in the raw data samples, such as sudden signal loss, extraneous or outlying data points, speed drifting, and signal white noise, all of which limit the quality of field data for use in downstream applications. Unaddressed, these errors significantly impact the reliability of source data and limit the effectiveness of traditional drive-cycle analysis approaches and vehicle simulation software. Without reliable speed and time information, the validity of derived metrics for drive cycles, such as acceleration, power, and distance, become questionable. This study exploresmore » some of the common sources of error present in raw onboard GPS data and presents a detailed filtering process designed to correct for these issues. Test data from both light and medium/heavy duty applications are examined to illustrate the effectiveness of the proposed filtration process across the range of vehicle vocations. Graphical comparisons of raw and filtered cycles are presented, and statistical analyses are performed to determine the effects of the proposed filtration process on raw data. Finally, an evaluation of the overall benefits of data filtration on raw GPS data and present potential areas for continued research is presented.« less

The impact of center city economic and cultural vibrancy on greenhouse gas emissions from transportation : [research brief].

DOT National Transportation Integrated Search

2012-03-01

Policy makers across the country are keenly interested in reducing emissions from driving and increasing public transit use. Guided by a large literature documenting the connections between urban sprawl, more driving and less public transit use, land...

75 FR 29199 - Changes in Flood Elevation Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-25

... under the criteria of section 3(f) of Executive Order 12866 of September 30, 1993, Regulatory Planning..., 8700 Hospital Drive, Douglasville, GA 30134. Kentucky: Lexington-Fayette Urban Lexington-Fayette February 12, 2010; The Honorable Jim June 21, 2010 210067 County Government. Urban County February 19, 2010...

Effect of In-Vehicle Audio Warning System on Driver’s Speed Control Performance in Transition Zones from Rural Areas to Urban Areas

PubMed Central

Yan, Xuedong; Wang, Jiali; Wu, Jiawei

2016-01-01

Speeding is a major contributing factor to traffic crashes and frequently happens in areas where there is a mutation in speed limits, such as the transition zones that connect urban areas from rural areas. The purpose of this study is to investigate the effects of an in-vehicle audio warning system and lit speed limit sign on preventing drivers’ speeding behavior in transition zones. A high-fidelity driving simulator was used to establish a roadway network with the transition zone. A total of 41 participants were recruited for this experiment, and the driving speed performance data were collected from the simulator. The experimental results display that the implementation of the audio warning system could significantly reduce drivers’ operating speed before they entered the urban area, while the lit speed limit sign had a minimal effect on improving the drivers’ speed control performance. Without consideration of different types of speed limit signs, it is found that male drivers generally had a higher operating speed both upstream and in the transition zones and have a larger maximum deceleration for speed reduction than female drivers. Moreover, the drivers who had medium-level driving experience had the higher operating speed and were more likely to have speeding behaviors in the transition zones than those who had low-level and high-level driving experience in the transition zones. PMID:27347990

The Development of Vocational Vehicle Drive Cycles and Segmentation

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

Duran, Adam W.; Phillips, Caleb T.; Konan, Arnaud M.

Under a collaborative interagency agreement between the U.S. Environmental Protection Agency and the U.S Department of Energy (DOE), the National Renewable Energy Laboratory (NREL) performed a series of in-depth analyses to characterize the on-road driving behavior including distributions of vehicle speed, idle time, accelerations and decelerations, and other driving metrics of medium- and heavy-duty vocational vehicles operating within the United States. As part of this effort, NREL researchers segmented U.S. medium- and heavy-duty vocational vehicle driving characteristics into three distinct operating groups or clusters using real world drive cycle data collected at 1 Hz and stored in NREL's Fleet DNAmore » database. The Fleet DNA database contains millions of miles of historical real-world drive cycle data captured from medium- and heavy vehicles operating across the United States. The data encompass data from existing DOE activities as well as contributions from valued industry stakeholder participants. For this project, data captured from 913 unique vehicles comprising 16,250 days of operation were drawn from the Fleet DNA database and examined. The Fleet DNA data used as a source for this analysis has been collected from a total of 30 unique fleets/data providers operating across 22 unique geographic locations spread across the United States. This includes locations with topology ranging from the foothills of Denver, Colorado, to the flats of Miami, Florida. The range of fleets, geographic locations, and total number of vehicles analyzed ensures results that include the influence of these factors. While no analysis will be perfect without unlimited resources and data, it is the researchers understanding that the Fleet DNA database is the largest and most thorough publicly accessible vocational vehicle usage database currently in operation. This report includes an introduction to the Fleet DNA database and the data contained within, a presentation of the results of the statistical analysis performed by NREL, review of the logistic model developed to predict cluster membership, and a discussion and detailed summary of the development of the vocational drive cycle weights and representative transient drive cycles for testing and simulation. Additional discussion of known limitations and potential future work are also included in the report content.« less

A Case Study on Nitrogen Uptake and Denitrification in a Restored Urban Stream in Baltimore, Maryland

EPA Science Inventory

Restoring urban infrastructure and managing the nitrogen cycle represent emerging challenges for urban water quality. We investigated whether stormwater control measures (SCMs), a form of green infrastructure, integrated into restored and degraded urban stream networks can influe...

Drivers’ Visual Characteristics when Merging onto or Exiting an Urban Expressway

PubMed Central

Cheng, Ying; Gao, Li; Zhao, Yanan; Du, Feng

2016-01-01

The aim of this study is to examine drivers’ visual and driving behavior while merging onto or exiting an urban expressway with low and high traffic densities. The analysis was conducted according to three periods (approaching, merging or exiting, and accelerating or decelerating). A total of 10 subjects (8 males and 2 females) with ages ranging from 25 to 52 years old (M = 30.0 years old) participated in the study. The research was conducted in a natural driving situation, and the drivers’ eye movements were monitored and recorded using an eye tracking system. The results show that the influence of traffic density on the glance duration and scan duration is more significant when merging than when exiting. The results also demonstrate that the number of glances and the mean glance duration are mainly related to the driving task (e.g., the merging period). Therefore, drivers’ visual search strategies mainly depend on the current driving task. With regard to driving behavior, the variation tendencies of the duration and the velocity of each period are similar. These results support building an automated driving assistant system that can automatically identify gaps and accelerate or decelerate the car accordingly or provide suggestions to the driver to do so. PMID:27657888

New Mexico's 1998 drive-up liquor window closure. Study II: economic impact on owners.

PubMed

Lapham, Sandra C; Skipper, Betty J

2004-05-01

This study examined the economic impact of the New Mexico legislative action closing drive-up liquor windows on the retail establishments that operated them. A telephone survey was conducted 20 months after the closure seeking information and owners' opinions about how their outlets had changed since the closure and how this affected their business. In addition, 2 years of aggregated pre- and post-closure total gross receipts revenues were obtained from the New Mexico Taxation and Revenue Department, with convenience stores as a comparison group. Interviews were completed for 149 of 220 establishments. Over one-quarter of former drive-up liquor windows (28%) had been converted to 'step-in' sales, defined as an outside door where customers can stop and enter the premises while their car is running. Almost two-thirds (61%) of owners reported decreased annual gross revenues following closure, with a reported average 15% reduction in alcohol sales. This is consistent with findings of decreased gross receipts for operators of non-urban, but not urban, drive-up liquor windows compared to convenience store gross receipts. Almost three-quarters (72%) of those surveyed would re-open the drive-up window if the law were rescinded. Over one-quarter of the drive-up owners converted to step-in alcohol sales that still allow a form of drive-up liquor sales. Despite this, the forced closure of New Mexico's drive-up liquor windows negatively impacted total sales and liquor sales revenues of establishments that operated them.

How much can you drink before driving? The influence of riding with impaired adults and peers on the driving behaviors of urban and rural youth.

PubMed

Leadbeater, Bonnie J; Foran, Kathleen; Grove-White, Aidan

2008-04-01

Following an ecological model to specify risks for impaired driving, we assessed the effects of youth attitudes about substance use and their experiences of riding in cars with adults and peers who drove after drinking alcohol or smoking cannabis on the youths' own driving after drinking or using cannabis. Participants were 2594 students in grades 10 and 12 (mean age = 16 years and 2 months; 50% girls) from public high schools in urban (994) and rural communities (1600) on Vancouver Island in British Columbia, Canada; 1192 of these were new drivers with restricted licenses. Self-report data were collected in anonymous questionnaires. Regression analyses were used to assess the independent and interacting effects of youth attitudes about substance use and their experiences of riding in cars with adults or peers who drove after drinking alcohol or smoking cannabis on youth driving. Youth driving risk behaviors were associated independently with their own high-risk attitudes and experiences riding with peers who drink alcohol or use cannabis and drive. However, risks were highest for the youth who also report more frequent experiences of riding with adults who drink alcohol or use cannabis and drive. Prevention efforts should be expanded to include the adults and peers who are role models for new drivers and to increase youths' awareness of their own responsibilities for their personal safety as passengers.

A framework to investigate drivers of adaptation decisions in marine fishing: Evidence from urban, semi-urban and rural communities.

PubMed

Malakar, Krishna; Mishra, Trupti; Patwardhan, Anand

2018-05-11

Traditional fishing livelihoods need to adapt to changing fish catch/populations, led by numerous anthropogenic, environmental and climatic stressors. The decision to adapt can be influenced by a variety of socio-economic and perceptual factors. However, adaptation decision-making in fishing communities has rarely been studied. Based on previous literature and focus group discussions with community, this study identifies few prominent adaptation responses in marine fishing and proposes credible factors driving decisions to adopt them. Further, a household survey is conducted, and the association of these drivers with various adaptation strategies is examined among fisherfolk of Maharashtra (India). This statistical analysis is based on 601 responses collected across three regional fishing groups: urban, semi-urban and rural. Regional segregation is done to understand variability in decision-making among groups which might be having different socio-economic and perceptual attributes. The survey reveals that only few urban fishing households have been able to diversify into other livelihoods. While having economic capital increases the likelihood of adaptation among urban and semi-urban communities, rural fishermen are significantly driven by social capital. Perception of climate change affecting fish catch drives adoption of mechanized boats solely in urban region. But increasing number of extreme events affects decisions of semi-urban and rural fishermen. Further, rising pollution and trade competition is associated with adaptation responses in the urban and semi-urban community. Higher education might help fishermen choose convenient forms of adaptation. Also, cooperative membership and subsidies are critical in adaptation decisions. The framework and insights of the study suggest the importance of acknowledging differential decision-making of individuals and communities, for designing effective adaptation and capacity-building policies. Copyright © 2018 Elsevier B.V. All rights reserved.

LEO-to-GEO low thrust chemical propulsion

NASA Technical Reports Server (NTRS)

Shoji, J. M.

1980-01-01

One approach being considered for transporting large space structures from low Earth orbit (LEO) to geosynchronous equatorial orbit (GEO) is the use of low thrust chemical propulsion systems. A variety of chemical rocket engine cycles evaluated for this application for oxygen/hydrogen and oxygen/hydrocarbon propellants (oxygen/methane and oxygen/RF-1) are discussed. These cycles include conventional propellant turbine drives, turboalternator/electric motor pump drive, and fuel cell/electric motor pump drive as well as pressure fed engines. Thrust chamber cooling analysis results are presented for regenerative/radiation and film/radiation cooling.

Bus transit operational efficiency resulting from passenger boardings at park-and-ride facilities.

DOT National Transportation Integrated Search

2016-08-01

In order to save time and money by not driving to an ultimate destination, some urban commuters drive themselves a few miles to specially designated parking lots built for transit customers and located where trains or buses stop. The focus of this pa...

Comparing the diurnal and seasonal variabilities of atmospheric and surface urban heat islandsbased on the Beijing urban meteorological network

NASA Astrophysics Data System (ADS)

Jiang, S.; Wang, K.; Wang, J.; Zhou, C.; Wang, X.; Lee, X.

2017-12-01

This study compared the diurnal and seasonal cycles of atmospheric and surface urban heat islands (UHIs) based on hourly air temperatures (Ta) collected at 65 out of 262 stations in Beijing and land surface temperature (Ts) derived from Moderate Resolution Imaging Spectroradiometer in the years 2013-2014. We found that the nighttime atmospheric and surface UHIs referenced to rural cropland stations exhibited significant seasonal cycles, with the highest in winter. However, the seasonal variations in the nighttime UHIs referenced to mountainous forest stations were negligible, because mountainous forests have a higher nighttime Ts in winter and a lower nighttime T a in summer than rural croplands. Daytime surface UHIs showed strong seasonal cycles, with the highest in summer. The daytime atmospheric UHIs exhibited a similar but less seasonal cycle under clear-sky conditions, which was not apparent under cloudy-sky conditions. Atmospheric UHIs in urban parks were higher in daytime. Nighttime atmospheric UHIs are influenced by energy stored in urban materials during daytime and released during nighttime. The stronger anthropogenic heat release in winter causes atmospheric UHIs to increase with time during winter nights, but decrease with time during summer nights. The percentage of impervious surfaces is responsible for 49%-54% of the nighttime atmospheric UHI variability and 31%-38% of the daytime surface UHI variability. However, the nighttime surface UHI was nearly uncorrelated with the percentage of impervious surfaces around the urban stations.

Impacts of urbanisation on urban-rural water cycle: a China case study

NASA Astrophysics Data System (ADS)

Wang, Mingna; Singh, Shailesh Kumar; Zhang, Jun-e.; Khu, Soon Thiam

2016-04-01

Urbanization, which essentially create more impervious surface, is an inevitable part of modern societal development throughout the world. It produces several changes in the natural hydrological cycle by adding several processes. A better understanding of the impacts of urbanization, will allow policy makers to balance development and environment sustainability needs. It also helps underdeveloped countries make strategic decisions in their development process. The objective of this study is to understand and quantify the sensitivity of the urban-rural water cycle to urbanisation. A coupled hydrological model, MODCYCLE, was set up to simulate the effect of changes in landuse on daily streamflow and groundwater and applied to the Tianjin municipality, a rapidly urbanising mega-city on the east coast of China. The model uses landuse, land cover, soil, meteorological and climatic data to represent important parameters in the catchment. The fraction of impervious surface was used as a surrogate to quantify the degree of landuse change. In this work, we analysed the water cycle process under current urbanization situation in Tianjin. A number of different future development scenarios on based on increasing urbanisation intensity is explored. The results show that the expansion of urban areas had a great influence on generation of flow process and on ET, and the surface runoff was most sensitive to urbanisation. The results of these scenarios-based study about future urbanisation on hydrological system will help planners and managers in taking proper decisions regarding sustainable development.

Driving range estimation for electric vehicles based on driving condition identification and forecast

NASA Astrophysics Data System (ADS)

Pan, Chaofeng; Dai, Wei; Chen, Liao; Chen, Long; Wang, Limei

2017-10-01

With the impact of serious environmental pollution in our cities combined with the ongoing depletion of oil resources, electric vehicles are becoming highly favored as means of transport. Not only for the advantage of low noise, but for their high energy efficiency and zero pollution. The Power battery is used as the energy source of electric vehicles. However, it does currently still have a few shortcomings, noticeably the low energy density, with high costs and short cycle life results in limited mileage compared with conventional passenger vehicles. There is great difference in vehicle energy consumption rate under different environment and driving conditions. Estimation error of current driving range is relatively large due to without considering the effects of environmental temperature and driving conditions. The development of a driving range estimation method will have a great impact on the electric vehicles. A new driving range estimation model based on the combination of driving cycle identification and prediction is proposed and investigated. This model can effectively eliminate mileage errors and has good convergence with added robustness. Initially the identification of the driving cycle is based on Kernel Principal Component feature parameters and fuzzy C referring to clustering algorithm. Secondly, a fuzzy rule between the characteristic parameters and energy consumption is established under MATLAB/Simulink environment. Furthermore the Markov algorithm and BP(Back Propagation) neural network method is utilized to predict the future driving conditions to improve the accuracy of the remaining range estimation. Finally, driving range estimation method is carried out under the ECE 15 condition by using the rotary drum test bench, and the experimental results are compared with the estimation results. Results now show that the proposed driving range estimation method can not only estimate the remaining mileage, but also eliminate the fluctuation of the residual range under different driving conditions.

Urban Excellence Framework

ERIC Educational Resources Information Center

New Leaders (NJ1), 2011

2011-01-01

A principal's job, first and foremost, is to diagnose their school's needs and match them to effective principal actions and school practices that drive student success. Successful principals use their diagnosis to build an action plan that pushes their school--and student achievement--to the next level. New Leaders developed the Urban Excellence…

40 CFR 86.215-94 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1994 and Later Model Year Gasoline-Fueled New Light-Duty Vehicles, New Light-Duty Trucks and New Medium-Duty Passenger Vehicles; Cold Temperature Test Procedures § 86.215-94 EPA urban dynamometer...

URBANIZATION EFFECTS ON TREE GROWTH IN THE VICINITY OF NEW YORK CITY

EPA Science Inventory

Plants in urban ecosystems are exposed to many pollutants and higher temperatures, CO2 and nitrogen deposition than plants in rural areas. Although each factor has a detrimental or beneficial influence on plant growth, the net effect of all factors and the key driving variables a...

Urban ecosystems and the North American carbon cycle

Treesearch

D.E. Pataki; R.J. Alig; A.S. Fung; E. Golubiewski; C.A. Kennedy; E.G. McPherson; D.J. Nowak; R.V. Pouyat; P. Romero Lankao

2006-01-01

Approximately 75-80% of the population of North America currently lives in urban areas as defined by national census bureaus, and urbanization is continuing to increase. Future trajectories of fossil fuel emissions are associated with a high degree of uncertainty; however, if the activities of urban residents and the rate of urban land conversion can be captured in...

Redesigning Urban Carbon Cycles: from Waste Stream to Commodity

NASA Astrophysics Data System (ADS)

Brabander, D. J.; Fitzstevens, M. G.

2013-12-01

While there has been extensive research on the global scale to quantify the fluxes and reservoirs of carbon for predictive climate change models, comparably little attention has been focused on carbon cycles in the built environment. The current management of urban carbon cycles presents a major irony: while cities produce tremendous fluxes of organic carbon waste, their populations are dependent on imported carbon because most urban have limited access to locally sourced carbon. The persistence of outdated management schemes is in part due to the fact that reimagining the handling of urban carbon waste streams requires a transdisciplinary approach. Since the end of the 19th century, U.S. cities have generally relied on the same three options for managing organic carbon waste streams: burn it, bury it, or dilute it. These options still underpin the framework for today's design and management strategies for handling urban carbon waste. We contend that urban carbon management systems for the 21st century need to be scalable, must acknowledge how climate modulates the biogeochemical cycling of urban carbon, and should carefully factor local political and cultural values. Urban waste carbon is a complex matrix ranging from wastewater biosolids to municipal compost. Our first goal in designing targeted and efficient urban carbon management schemes has been examining approaches for categorizing and geochemically fingerprinting these matrices. To date we have used a combination of major and trace element ratio analysis and bulk matrix characteristics, such as pH, density, and loss on ignition, to feed multivariable statistical analysis in order to identify variables that are effective tracers for each waste stream. This approach was initially developed for Boston, MA, US, in the context of identifying components of municipal compost streams that were responsible for increasing the lead inventory in the final product to concentrations that no longer permitted its use in supporting urban agriculture. We are now extending this approach to additional large U.S. and European urban centers where different philosophical and technological approaches to managing urban waste carbon have resulted in a range of infrastructures, from highly distributed systems (Germany) to centralized mega facilities (London). Ultimately, this research will lead to a decision-making matrix model that will permit cities to customize their urban carbon waste stream facilities and transform this waste into a usable commodity.

Population perspective is widening. Interview: Louise Lassonde.

PubMed

1992-01-01

Commentary is provided on the link between poverty and population growth, the link between population growth and the environment, solutions in general and at the village level, integrated programs, urban growth, and critical policies. Developing countries do recognize that rural poverty is part of the cycle of urban migration and population dynamics. Poverty also must be treated separately from population growth issues. An important issue is the reproductive health of women, their economic opportunities, and empowerment in decision making and access to information. Another important issue is the link between human species survival and the biosphere. Both issues need to be addressed and there is no contradiction between the issues; each is reinforcing of the other in policy. At the village level improving the personal, social, and environmental gains for women in villages with high fertility and soil erosion, deforestation, and water shortages serves both concerns. Programmatically, this means more information for women, better reproductive health services for women, improved social services, tree planting programs, water use programs, and environmental protection programs. Central planning is needed, but also decentralization in implementation and decision making. Urban population growth does not lend itself to ready-made solutions. The positive is that it offers modernization and the possibility of improved social services; the negative is how to provide the services. Both population dynamics and underlying infrastructure and urban management must work together. Recommendations are 3-fold. 1) Technology, the production/consumption process, and population dynamics are the major driving forces of environmental change. 2) The planning approach needs to be reconsidered: population dynamics and implications must be integrated at every level of planning. 3) Policies that recognize the aforementioned points will induce political will to implement activities and programs.

Using Map Service API for Driving Cycle Detection for Wearable GPS Data: Preprint

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

Zhu, Lei; Gonder, Jeffrey D

Following advancements in smartphone and portable global positioning system (GPS) data collection, wearable GPS data have realized extensive use in transportation surveys and studies. The task of detecting driving cycles (driving or car-mode trajectory segments) from wearable GPS data has been the subject of much research. Specifically, distinguishing driving cycles from other motorized trips (such as taking a bus) is the main research problem in this paper. Many mode detection methods only focus on raw GPS speed data while some studies apply additional information, such as geographic information system (GIS) data, to obtain better detection performance. Procuring and maintaining dedicatedmore » road GIS data are costly and not trivial, whereas the technical maturity and broad use of map service application program interface (API) queries offers opportunities for mode detection tasks. The proposed driving cycle detection method takes advantage of map service APIs to obtain high-quality car-mode API route information and uses a trajectory segmentation algorithm to find the best-matched API route. The car-mode API route data combined with the actual route information, including the actual mode information, are used to train a logistic regression machine learning model, which estimates car modes and non-car modes with probability rates. The experimental results show promise for the proposed method's ability to detect vehicle mode accurately.« less

49 CFR 571.126 - Standard No. 126; Electronic stability control systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... cycle that is designed for low-speed, off-road driving, or (b) the vehicle is in a four-wheel drive configuration selected by the driver on the previous ignition cycle that is designed for operation at higher.... Light outriggers are designed with a maximum weight of 27 kg (59.5 lb) and a maximum roll moment of...

Combined cycle power plant incorporating coal gasification

DOEpatents

Liljedahl, Gregory N.; Moffat, Bruce K.

1981-01-01

A combined cycle power plant incorporating a coal gasifier as the energy source. The gases leaving the coal gasifier pass through a liquid couplant heat exchanger before being used to drive a gas turbine. The exhaust gases of the gas turbine are used to generate both high pressure and low pressure steam for driving a steam turbine, before being exhausted to the atmosphere.

Diurnal, synoptic and seasonal variability of atmospheric CO2 in the Paris megacity area

NASA Astrophysics Data System (ADS)

Xueref-Remy, Irène; Dieudonné, Elsa; Vuillemin, Cyrille; Lopez, Morgan; Lac, Christine; Schmidt, Martina; Delmotte, Marc; Chevallier, Frédéric; Ravetta, François; Perrussel, Olivier; Ciais, Philippe; Bréon, François-Marie; Broquet, Grégoire; Ramonet, Michel; Spain, T. Gerard; Ampe, Christophe

2018-03-01

Most of the global fossil fuel CO2 emissions arise from urbanized and industrialized areas. Bottom-up inventories quantify them but with large uncertainties. In 2010-2011, the first atmospheric in situ CO2 measurement network for Paris, the capital of France, began operating with the aim of monitoring the regional atmospheric impact of the emissions coming from this megacity. Five stations sampled air along a northeast-southwest axis that corresponds to the direction of the dominant winds. Two stations are classified as rural (Traînou - TRN; Montgé-en-Goële - MON), two are peri-urban (Gonesse - GON; Gif-sur-Yvette - GIF) and one is urban (EIF, located on top of the Eiffel Tower). In this study, we analyze the diurnal, synoptic and seasonal variability of the in situ CO2 measurements over nearly 1 year (8 August 2010-13 July 2011). We compare these datasets with remote CO2 measurements made at Mace Head (MHD) on the Atlantic coast of Ireland and support our analysis with atmospheric boundary layer height (ABLH) observations made in the center of Paris and with both modeled and observed meteorological fields. The average hourly CO2 diurnal cycles observed at the regional stations are mostly driven by the CO2 biospheric cycle, the ABLH cycle and the proximity to urban CO2 emissions. Differences of several µmol mol-1 (ppm) can be observed from one regional site to the other. The more the site is surrounded by urban sources (mostly residential and commercial heating, and traffic), the more the CO2 concentration is elevated, as is the associated variability which reflects the variability of the urban sources. Furthermore, two sites with inlets high above ground level (EIF and TRN) show a phase shift of the CO2 diurnal cycle of a few hours compared to lower sites due to a strong coupling with the boundary layer diurnal cycle. As a consequence, the existence of a CO2 vertical gradient above Paris can be inferred, whose amplitude depends on the time of the day and on the season, ranging from a few tenths of ppm during daytime to several ppm during nighttime. The CO2 seasonal cycle inferred from monthly means at our regional sites is driven by the biospheric and anthropogenic CO2 flux seasonal cycles, the ABLH seasonal cycle and also synoptic variations. Enhancements of several ppm are observed at peri-urban stations compared to rural ones, mostly from the influence of urban emissions that are in the footprint of the peri-urban station. The seasonal cycle observed at the urban station (EIF) is specific and very sensitive to the ABLH cycle. At both the diurnal and the seasonal scales, noticeable differences of several ppm are observed between the measurements made at regional rural stations and the remote measurements made at MHD, that are shown not to define background concentrations appropriately for quantifying the regional ( ˜ 100 km) atmospheric impact of urban CO2 emissions. For wind speeds less than 3 m s-1, the accumulation of local CO2 emissions in the urban atmosphere forms a dome of several tens of ppm at the peri-urban stations, mostly under the influence of relatively local emissions including those from the Charles de Gaulle (CDG) Airport facility and from aircraft in flight. When wind speed increases, ventilation transforms the CO2 dome into a plume. Higher CO2 background concentrations of several ppm are advected from the remote Benelux-Ruhr and London regions, impacting concentrations at the five stations of the network even at wind speeds higher than 9 m s-1. For wind speeds ranging between 3 and 8 m s-1, the impact of Paris emissions can be detected in the peri-urban stations when they are downwind of the city, while the rural stations often seem disconnected from the city emission plume. As a conclusion, our study highlights a high sensitivity of the stations to wind speed and direction, to their distance from the city, but also to the ABLH cycle depending on their elevation. We learn some lessons regarding the design of an urban CO2 network: (1) careful attention should be paid to properly setting regional (˜ 100 km) background sites that will be representative of the different wind sectors; (2) the downwind stations should be positioned as symmetrically as possible in relation to the city center, at the peri-urban/rural border; (3) the stations should be installed at ventilated sites (away from strong local sources) and the air inlet set up above the building or biospheric canopy layer, whichever is the highest; and (4) high-resolution wind information should be available with the CO2 measurements.

Oil strategies benefits over different driving cycles using numerical simulation

NASA Astrophysics Data System (ADS)

Sara, Hanna; Chalet, David; Cormerais, Mickaël; Hetet, Jean-François

2017-08-01

95 g/km is the allowed quantity of CO2 emission normalized to NEDC to be set in 2020. In addition, NEDC will be replaced by more severe driving cycles and will be united worldwide. To respond to those criteria, automotive industries are working on every possible field. Thermal management has been proved to be effective in reducing fuel consumption. Cold start is a primordial reason of overconsumption, as the engine highest efficiency is at its optimal temperature. At cold start, the engine's oil is at its lowest temperature and thus its higher viscosity level. A high viscosity oil generates more friction, which is one of the most important heat losses in the engine. In this paper, hot oil storage is studied. Numerical simulations on GT-suite model were done. The model consists of a 4-cylinder turbocharged Diesel engine using a storage volume of 1 liter of hot oil. Ambient temperature variation were taken into consideration as well as different driving cycles. Furthermore, different configurations of the thermal strategy (multifunction oil sump) were proposed and evaluated. Lubricant temperature and viscosity profiles are presented in the article as well as fuel consumption savings for different configurations, driving cycles and ambient temperatures.

Serial Charging Test on High Capacity Li-Ion Cells for the Orbiter Advanced Hydraulic Power System

NASA Technical Reports Server (NTRS)

Jeevarajan, Judith A.; Irlbeck, Brad

2006-01-01

Although it looks like module level voltage drives the cutoff for charge, the actual cutoff is due to unbalanced cell voltages that drive the module voltage up. Individual cell voltage drives the cutoff for discharge Low resistance cells are the first to reach the low-voltage cutoff Cell-to-Cell voltage differences are generally small and show similar trends for each cycle Increase for a distinct window during charge and at the end of discharge Increase in max to min cell voltage difference with time/cycles Decrease in max to min cell voltage difference during high current pulses with time/cycles Individual cell voltage trends (with respect to other cells) are very repeatable from cycle to cycle, although voltage slowly degrades with time/cycles (resistance growth) Much more difference observed near end of discharge Little change in order of cell voltage (cell with highest voltage to cell with lowest voltage) Temp sensor on the side of cell (between 2 cells) shows much greater rise during discharge than for single cell tests (18 C vs 5 C) Conclusion: Serial Charging of this string of cells is feasible as it has only a minor impact on useful capacity

Glutamine metabolism and cycling in Neurospora crassa.

PubMed Central

Mora, J

1990-01-01

Evidence for the existence of a glutamine cycle in Neurospora crassa is reviewed. Through this cycle glutamine is converted into glutamate by glutamate synthase and catabolized by the glutamine transaminase-omega-amidase pathway, the products of which (2-oxoglutarate and ammonium) are the substrates for glutamate dehydrogenase-NADPH, which synthesizes glutamate. In the final step ammonium is assimilated into glutamine by the action of a glutamine synthetase (GS), which is formed by two distinct polypeptides, one catalytically very active (GS beta), and the other (GS alpha) less active but endowed with the capacity to modulate the activity of GS alpha. Glutamate synthase uses the amide nitrogen of glutamine to synthesize glutamate; glutamate dehydrogenase uses ammonium, and both are required to maintain the level of glutamate. The energy expended in the synthesis of glutamine drives the cycle. The glutamine cycle is not futile, because it is necessary to drive an effective carbon flow to support growth; in addition, it facilitates the allocation of nitrogen or carbon according to cellular demands. The glutamine cycle which dissipates energy links catabolism and anabolism and, in doing so, buffers variations in the nutrient supply and drives energy generation and carbon flow for optimal cell function. PMID:2145504

Accounting for urban biogenic fluxes in regional carbon budgets.

PubMed

Hardiman, Brady S; Wang, Jonathan A; Hutyra, Lucy R; Gately, Conor K; Getson, Jackie M; Friedl, Mark A

2017-08-15

Many ecosystem models incorrectly treat urban areas as devoid of vegetation and biogenic carbon (C) fluxes. We sought to improve estimates of urban biomass and biogenic C fluxes using existing, nationally available data products. We characterized biogenic influence on urban C cycling throughout Massachusetts, USA using an ecosystem model that integrates improved representation of urban vegetation, growing conditions associated with urban heat island (UHI), and altered urban phenology. Boston's biomass density is 1/4 that of rural forests, however 87% of Massachusetts' urban landscape is vegetated. Model results suggest that, kilogram-for-kilogram, urban vegetation cycles C twice as fast as rural forests. Urban vegetation releases (R E ) and absorbs (GEE) the equivalent of 11 and 14%, respectively, of anthropogenic emissions in the most urban portions of the state. While urban vegetation in Massachusetts fully sequesters anthropogenic emissions from smaller cities in the region, Boston's UHI reduces annual C storage by >20% such that vegetation offsets only 2% of anthropogenic emissions. Asynchrony between temporal patterns of biogenic and anthropogenic C fluxes further constrains the emissions mitigation potential of urban vegetation. However, neglecting to account for biogenic C fluxes in cities can impair efforts to accurately monitor, report, verify, and reduce anthropogenic emissions. Copyright © 2017 Elsevier B.V. All rights reserved.

[Spatiotemporal characteristics of urban land expansion in central area of Shanghai, China].

PubMed

Hu, Han-Wen; Wei, Ben-Sheng; Shen, Xing-Hua; Li, Jun-Xiang

2013-12-01

Using the high spatial resolution (2.5 m) color-infrared aerial photos acquired in 1989, 1994, 2000 and 2005, this paper analyzed the spatiotemporal characteristics of rapid urban expansion in central Shanghai with urban expansion intensity index and gradient analysis. Results showed that urban land use in Shanghai increased rapidly in a "pancake" style during the study period, and the anisotropic urban expansion moved the urban center 2.62 km toward southwest. The urban land use expansion intensity doubled and showed a rural-urban gradient. The most intensive urban expansion zone fell in the rural-urban transition zone, indicating the dominance of peripheral expansion as the primary urban expansion mode in Shanghai. However, the urban land use intensity decreased with time at the urban center. The primary driving forces of urban expansion included support from government policies and decision-making, enhanced economic activities, societal fixed assets investment, urban infrastructure investment, extension of transportation routes, as well as increase in urban population.

Modelling the catchment-scale environmental impacts of wastewater treatment in an urban sewage system for CO₂ emission assessment.

PubMed

Mouri, Goro; Oki, Taikan

2010-01-01

Water shortages and water pollution are a global problem. Increases in population can have further acute effects on water cycles and on the availability of water resources. Thus, wastewater management plays an important role in mitigating negative impacts on natural ecosystems and human environments and is an important area of research. In this study, we modelled catchment-scale hydrology, including water balances, rainfall, contamination, and urban wastewater treatment. The entire water resource system of a basin, including a forest catchment and an urban city area, was evaluated synthetically from a spatial distribution perspective with respect to water quantity and quality; the Life Cycle Assessment (LCA) technique was applied to optimize wastewater treatment management with the aim of improving water quality and reducing CO₂ emissions. A numerical model was developed to predict the water cycle and contamination in the catchment and city; the effect of a wastewater treatment system on the urban region was evaluated; pollution loads were evaluated quantitatively; and the effects of excluding rainwater from the treatment system during flooding and of urban rainwater control on water quality were examined. Analysis indicated that controlling the amount of rainwater inflow to a wastewater treatment plant (WWTP) in an urban area with a combined sewer system has a large impact on reducing CO₂ emissions because of the load reduction on the urban sewage system.

Exploration of Urban Spatial Planning Evaluation Based on Humanland Harmony

NASA Astrophysics Data System (ADS)

Hu, X. S.; Ma, Q. R.; Liang, W. Q.; Wang, C. X.; Xiong, X. Q.; Han, X. H.

2017-09-01

This study puts forward a new concept, "population urbanization level forecast - driving factor analysis - urban spatial planning analysis" for achieving efficient and intensive development of urbanization considering human-land harmony. We analyzed big data for national economic and social development, studied the development trends of population urbanization and its influencing factors using the grey system model in Chengmai county of Hainan province, China. In turn, we calculated the population of Chengmai coming years based on the forecasting urbanization rate and the corresponding amount of urban construction land, and evaluated the urban spatial planning with GIS spatial analysis method in the study area. The result shows that the proposed concept is feasible for evaluation of urban spatial planning, and is meaningful for guiding the rational distribution of urban space, controlling the scale of development, improving the quality of urbanization and thus promoting highly-efficient and intensive use of limited land resource.

Urban ecosystems and the North American carbon cycle

Treesearch

D.E. Pataki; R.J. Alig; A.S. Fung; N.E. Golubiewski; C.A. Kennedy; E.G. McPherson; D.J. Nowak; R.V. Pouyat; P.R. Lankao

2006-01-01

Approximately 75–80% of the population of North America currently lives in urban areas as defined by national census bureaus, and urbanization is continuing to increase. Future trajectories of fossil fuel emissions are associated with a high degree of uncertainty; however, if the activities of urban residents and the rate of urban land conversion can be captured in...

40 CFR 86.515-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2010 CFR

2010-07-01

... I(b) (b) The speed tolerance at any given time on the dynamometer driving schedule prescribed in... than the tolerances (such as may occur during gear changes) are acceptable provided they occur for less... requirements of § 86.532 the speed tolerance shall be as specified above, except that the upper and lower...

Dual Expander Cycle Rocket Engine with an Intermediate, Closed-cycle Heat Exchanger

NASA Technical Reports Server (NTRS)

Greene, William D. (Inventor)

2008-01-01

A dual expander cycle (DEC) rocket engine with an intermediate closed-cycle heat exchanger is provided. A conventional DEC rocket engine has a closed-cycle heat exchanger thermally coupled thereto. The heat exchanger utilizes heat extracted from the engine's fuel circuit to drive the engine's oxidizer turbomachinery.

Can air pollution negate the health benefits of cycling and walking?

PubMed

Tainio, Marko; de Nazelle, Audrey J; Götschi, Thomas; Kahlmeier, Sonja; Rojas-Rueda, David; Nieuwenhuijsen, Mark J; de Sá, Thiago Hérick; Kelly, Paul; Woodcock, James

2016-06-01

Active travel (cycling, walking) is beneficial for the health due to increased physical activity (PA). However, active travel may increase the intake of air pollution, leading to negative health consequences. We examined the risk-benefit balance between active travel related PA and exposure to air pollution across a range of air pollution and PA scenarios. The health effects of active travel and air pollution were estimated through changes in all-cause mortality for different levels of active travel and air pollution. Air pollution exposure was estimated through changes in background concentrations of fine particulate matter (PM2.5), ranging from 5 to 200μg/m3. For active travel exposure, we estimated cycling and walking from 0 up to 16h per day, respectively. These refer to long-term average levels of active travel and PM2.5 exposure. For the global average urban background PM2.5 concentration (22μg/m3) benefits of PA by far outweigh risks from air pollution even under the most extreme levels of active travel. In areas with PM2.5 concentrations of 100μg/m3, harms would exceed benefits after 1h 30min of cycling per day or more than 10h of walking per day. If the counterfactual was driving, rather than staying at home, the benefits of PA would exceed harms from air pollution up to 3h 30min of cycling per day. The results were sensitive to dose-response function (DRF) assumptions for PM2.5 and PA. PA benefits of active travel outweighed the harm caused by air pollution in all but the most extreme air pollution concentrations. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Alcohol Use and Abuse on an Urban Commuter Campus.

ERIC Educational Resources Information Center

Hunnicut, David M.; And Others

1992-01-01

Findings from 470 students at 1 urban commuter university revealed that sizable percentage of respondents reported consuming alcohol 10 or more times within last 30 days, drinking to intoxication 3 or more times within last 2 weeks, having family history of alcoholism, driving while using alcohol, missing class because of drinking, and receiving…

Analysis of the ability of water resources to reduce the urban heat island in the Tokyo megalopolis.

PubMed

Nakayama, Tadanobu; Hashimoto, Shizuka

2011-01-01

Simulation procedure integrated with multi-scale in horizontally regional-urban-point levels and in vertically atmosphere-surface-unsaturated-saturated layers, was newly developed in order to predict the effect of urban geometry and anthropogenic exhaustion on the hydrothermal changes in the atmospheric/land and the interfacial areas of the Japanese megalopolis. The simulated results suggested that the latent heat flux in new water-holding pavement (consisting of porous asphalt and water-holding filler made of steel by-products based on silica compound) has a strong impact on hydrologic cycle and cooling temperature in comparison with the observed heat budget. We evaluated the relationship between the effect of groundwater use as a heat sink to tackle the heat island and the effect of infiltration on the water cycle in the urban area. The result indicates that effective management of water resources would be powerful for ameliorating the heat island and recovering sound hydrologic cycle there. Copyright © 2010 Elsevier Ltd. All rights reserved.

Time-resolved characterization of primary particle emissions and secondary particle formation from a modern gasoline passenger car

NASA Astrophysics Data System (ADS)

Karjalainen, Panu; Timonen, Hilkka; Saukko, Erkka; Kuuluvainen, Heino; Saarikoski, Sanna; Aakko-Saksa, Päivi; Murtonen, Timo; Bloss, Matthew; Dal Maso, Miikka; Simonen, Pauli; Ahlberg, Erik; Svenningsson, Birgitta; Brune, William Henry; Hillamo, Risto; Keskinen, Jorma; Rönkkö, Topi

2016-07-01

Changes in vehicle emission reduction technologies significantly affect traffic-related emissions in urban areas. In many densely populated areas the amount of traffic is increasing, keeping the emission level high or even increasing. To understand the health effects of traffic-related emissions, both primary (direct) particulate emission and secondary particle formation (from gaseous precursors in the exhaust emissions) need to be characterized. In this study, we used a comprehensive set of measurements to characterize both primary and secondary particulate emissions of a Euro 5 level gasoline passenger car. Our aerosol particle study covers the whole process chain in emission formation, from the tailpipe to the atmosphere, and also takes into account differences in driving patterns. We observed that, in mass terms, the amount of secondary particles was 13 times higher than the amount of primary particles. The formation, composition, number and mass of secondary particles was significantly affected by driving patterns and engine conditions. The highest gaseous and particulate emissions were observed at the beginning of the test cycle when the performance of the engine and the catalyst was below optimal. The key parameter for secondary particle formation was the amount of gaseous hydrocarbons in primary emissions; however, also the primary particle population had an influence.

Travel time and attrition from VHA care among women veterans: how far is too far?

PubMed

Friedman, Sarah A; Frayne, Susan M; Berg, Eric; Hamilton, Alison B; Washington, Donna L; Saechao, Fay; Maisel, Natalya C; Lin, Julia Y; Hoggatt, Katherine J; Phibbs, Ciaran S

2015-04-01

Travel time, an access barrier, may contribute to attrition of women veterans from Veterans Health Administration (VHA) care. We examined whether travel time influences attrition: (a) among women veterans overall, (b) among new versus established patients, and (c) among rural versus urban patients. This retrospective cohort study used logistic regression to estimate the association between drive time and attrition, overall and for new/established and rural/urban patients. In total, 266,301 women veteran VHA outpatients in the Fiscal year 2009. An "attriter" did not return for VHA care during the second through third years after her first 2009 visit (T0). Drive time (log minutes) was between the patient's residence and her regular source of VHA care. "New" patients had no VHA visits within 3 years before T0. Models included age, service-connected disability, health status, and utilization as covariates. Overall, longer drive times were associated with higher odds of attrition: drive time adjusted odds ratio=1.11 (99% confidence interval, 1.09-1.14). The relationship between drive time and attrition was stronger among new patients but was not modified by rurality. Attrition among women veterans is sensitive to longer drive time. Linking new patients to VHA services designed to reduce distance barriers (telemedicine, community-based clinics, mobile clinics) may reduce attrition among women new to VHA.

Mobile phone use while driving in a sample of Spanish university workers.

PubMed

Gras, M Eugenia; Cunill, Monica; Sullman, Mark J M; Planes, Montserrat; Aymerich, Maria; Font-Mayolas, Silvia

2007-03-01

A number of epidemiological studies have reported drivers who use a mobile phone while driving have an elevated risk of being involved in a crash. This is particularly concerning as a survey of drivers in the Spanish region of Catalunya found that approximately 87% own mobile phones. The present study investigated the reported frequency of mobile phone use on Spanish roads (for talking and using SMS), the characteristics of the drivers who use mobile phones while driving and whether they altered their driving behaviour when using a mobile phone. The research found that more than 60% use a mobile phone while driving and that the phone is mostly used for making calls, rather than using SMS. In general, males and females use mobile phones about the same reported frequency, although males were more likely to use a mobile phone to talk on the highway. The pattern for age was the same for both male and female participants, with the younger drivers using SMS more frequently than older drivers. On urban roads almost half of the drivers reported changing their driving behaviour when using a mobile phone, while on the highway this figure was slightly over 41%. The reported frequency of using a mobile phone to talk on urban roads was significantly correlated with crash involvement. However, this affect disappeared once the contributions of the demographic and descriptive variables had been partialled out.

Urban sprawl and miles driven daily by teenagers in the United States.

PubMed

Trowbridge, Matthew J; McDonald, Noreen C

2008-03-01

Urban sprawl's association with increased automobile reliance and daily mileage is well established among adults. However, sprawl's specific impact on teen driving exposure is unknown. Teen driver fatality rates per mile driven are significantly higher than adults, making the identification of environmental influences on travel behavior particularly important in this age group. Driving and demographic data for 4528 teens (weighted=10.5 million) aged 16-19 years were obtained from the 2001 National Household Transportation Survey (NHTS). County-level sprawl was measured using an index developed by Ewing et al. The association between daily miles driven by teens and sprawl, controlling for demographic characteristics, was modeled using ordinal logistic regression. The predicted probability of driving >20 miles in counties with varying degrees of sprawl also was calculated. Of the surveyed teens, 48% did not drive, 27% drove <20 miles/day, and 25% drove >20 miles/day. Of the 52% of teens who reported driving, the average distance driven was 15.6 miles/day. More-pronounced sprawl was associated with increased daily mileage (p<0.001). Overall, teens in sprawling counties were more than twice as likely to drive >20 miles/day than teens in compact counties. This trend was most prominent among the youngest drivers. For example, the predicted probability of boys aged 16-17 years driving >20 miles per day varied from 9% to 24% in compact versus sprawling counties. Sprawl is associated with increased daily mileage by teen drivers. Given the stark relationship between driving exposure and fatality risk among teens, increased efforts to understand and modify the effects of sprawl on adolescent driving behavior are necessary.

Effects of stormwater management and stream restoration on watershed nitrogen retention

EPA Science Inventory

Restoring urban infrastructure and managing the nitrogen cycle represent emerging challenges for urban water quality. We investigated whether stormwater control measures (SCMs), a form of green infrastructure, integrated into restored and degraded urban stream networks can influ...

Real-world vehicle emission factors in Chinese metropolis city--Beijing.

PubMed

Wang, Qi-dong; He, Ke-bin; Huo, Hong; Lents, James

2005-01-01

The dynamometer tests with different driving cycles and the real-world tests are presented. Results indicated the pollutants emission factors and fuel consumption factor with ECE15 + EUDC driving cycle usually take the lowest value and with real world driving cycle occur the highest value, and different driving cycles will lead to significantly different vehicle emission factors with the same vehicle. Relative to the ECE15 + EUDC driving cycle, the increasing rate of pollutant emission factors of CO, NOx and HC are - 0.42-2.99, -0.32-0.81 and -0.11-11 with FTP75 testing, 0.11-1.29, -0.77-0.64 and 0.47-10.50 with Beijing 1997 testing and 0.25-1.83, 0.09-0.75 and - 0.58-1.50 with real world testing. Compared to the carburetor vehicles, the retrofit and MPI + TWC vehicles' pollution emissionfactors decrease with different degree. The retrofit vehicle (Santana) will reduce 4.44%-58.44% CO, -4.95%-36.79% NOx, -32.32%-33.89% HC, and -9.39%-14.29% fuel consumption, and especially that the MPI + TWC vehicle will decrease CO by 82.48%-91.76%, NOx by 44.87%-92.79%, HC by 90.00%-93.89% and fuel consumption by 5.44%-10.55%. Vehicles can cause pollution at a very high rate when operated in high power modes; however, they may not often operate in these high power modes. In analyzing vehicle emissions, it describes the fraction of time that vehicles operate in various power modes. In Beijing, vehicles spend 90% of their operation in low power modes or decelerating.

Hydroxyl and Hydroperoxy Chemistry at the CalNex-LA 2010 Site: Measurements and Modeling

NASA Astrophysics Data System (ADS)

Griffith, S. M.; Hansen, R. F.; Dusanter, S.; Stevens, P. S.; Gilman, J. B.; Kuster, W. C.; Veres, P. R.; Graus, M.; Warneke, C.; De Gouw, J. A.; Young, C. J.; Washenfelder, R. A.; Brown, S. S.; Flynn, J. H.; Alvarez, S. L.; Grossberg, N.; Lefer, B. L.; Rappenglueck, B.; Mielke, L. H.; Osthoff, H. D.

2011-12-01

Hydroxyl (OH) and hydroperoxy (HO2) radicals are key species in the atmosphere driving the oxidation of organic trace gases leading to the production of ozone and secondary organic aerosols. Previous measurements of these radicals in urban environments have shown similarities and differences across sites due to differing levels of nitrogen oxides (NOx) and volatile organic compounds (VOCs), and the control strategies for dealing with these chemical species. Understanding the free radical chemistry is essential for effectively regulating NOx and VOC emissions and controlling ozone and other secondary pollutants. Measurements of OH and HO2 radicals were made using a laser-induced fluorescence technique as part of the CalNex LA campaign during May-June, 2010. Median HOx (OH + HO2) concentrations, as well as HO2-to-OH ratios, were similar to previous measurements in other urban areas. An extensive suite of supporting measurements including photolysis rates, NOx, and other inorganic species, biogenic, aromatic, and other anthropogenic VOCs are used to constrain a zero-dimensional box model based on the Regional Atmospheric Chemistry Mechanism. Model comparisons provide details about the ability of commonly used chemical mechanisms to reproduce HOx production and loss rates, the radical cycling, and instantaneous O3 production rates in the Los Angeles area.

Urban Growth in a Fragmented Landscape: Estimating the Relationship between Landscape Pattern and Urban Land Use Change in Germany, 2000-2006

NASA Astrophysics Data System (ADS)

Keller, R.

2013-12-01

One of the highest priorities in the conservation and management of biodiversity, natural resources and other vital ecosystem services is the assessment of the mechanisms that drive urban land use change. Using key landscape indicators, this study addresses why urban land increased 6 percent overall in Germany from 2000-2006. Building on regional science and economic geography research, I develop a model of landscape change that integrates remotely sensed and other geospatial data, and socioeconomic data in a spatial autoregressive model to explain the variance in urban land use change observed in German kreise (counties) over the past decade. The results reveal three key landscape mechanisms that drive urban land use change across Germany, aligning with those observed in US studies: (1) the level of fragmentation, (2) the share of designated protected areas, and (3) the share of prime soil. First, as fragmentation of once continuous habitats in the landscape increases, extensive urban growth follows. Second, designated protected areas have the perverse effect of hastening urbanization in surrounding areas. Third, greater shares of prime, productive soil experienced less urban land take over the 6 year period, an effect that is stronger in the former East Germany, where the agricultural sector remains large. The results suggest that policy makers concentrate their conservation efforts on preexisting fragmented land with high shares of protected areas in Germany to effectively stem urban land take. Given that comparative studies of land use change are vital for the scientific community to grasp the wider global process of urbanization and coincident ecological impacts, the methodology employed here is easily exportable to land cover and land use research programs in other fields and geographic areas. Key words: Urban land use change, Ecosystem services, Landscape fragmentation, Remote sensing, Spatial regression models, GermanyOLS and Spatial Autoregressive Model Results N = 439; Standard error in ( ) . *p < .1, **p < .01, ***p < .001

Research on Power Loss of Continuously Variable Transmission Based on Driving Cycles

NASA Astrophysics Data System (ADS)

Fu, Bing; Zhou, Yunshan; Cao, Chenglong; Li, Quan; Zhang, Feitie

2018-01-01

In order to further enhance the fuel economy of vehicles with continuously variable transmission (CVT), a CVT power loss model under dynamic condition is established based on the power loss model of each transmission component and the vehicle dynamic model. With driving cycles 10-15, NEDC and US06 as input, the distribution of CVT power loss and the influence of the main losses to vehicle fuel economy are analysed. The results show that the variation loss, oil pump loss and torque converter loss are the main losses of CVT power loss under driving cycles, and the metal belt and oil pump have relatively larger fuel saving potential. At low speed reducing the pump loss is more effective to fuel saving, while at high speed reducing the variation loss is more effective.

Comparison of real-world and certification emission rates for light duty gasoline vehicles.

PubMed

Khan, Tanzila; Frey, H Christopher

2018-05-01

U.S. light duty vehicles are subject to the U.S. Environmental Protection Agency (EPA) emission standards. Emission compliance is determined by certification testing of selected emissions from representative vehicles on standard driving cycles using chassis dynamometers. Test results are also used in many emission inventories. The dynamometer based emission rates are adjusted to provide the certification levels (CL), which must be lower than the standards for compliance. Although standard driving cycles are based on specific observations of real-world driving, they are not necessarily real-world representative. A systematic comparison of the real-world emission rates of U.S. light duty gasoline vehicles (LDGVs) versus CL, and emission standards has not been previously reported. The purpose of this work is to compare regulatory limits (both CLs and emission standards) and the real-world emissions of LDGVs. The sensitivity of the comparisons to cold start emission was assessed. Portable Emission Measurement Systems (PEMS) were used to measure hot stabilized exhaust emissions of 122 LDGVs on a specified 110 mile test route. Cold start emissions were measured with PEMS for a selected vehicle sample of 32 vehicles. Emissions were measured for carbon dioxide (CO 2 ), carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NO x ). For each vehicle, a Vehicle Specific Power (VSP) modal emission rate model was developed. The VSP modal rates were weighted by the standard driving cycles and real-world driving cycles to estimate the respective cycle average emission rates (CAERs). Measured vehicles were matched with certification test vehicles for comparison. For systematic trends in comparison, vehicles were classified into four groups based on the Tier 1 and Tier 2 emission regulation, and the vehicle type such as passenger car and passenger truck. Depending on the cycle-pollutant and the vehicle groups, hot stabilized CAERs are on average either statistically significantly higher than or significantly not different from the CLs, with the exception of CO on the US06 cycle, for which real-world rates are lower than CLs. Compared to the emission standards, hot stabilized CAERs are on average significantly lower. However, comparisons of CAERs and standards are sensitive to cold start emissions. For some combinations of pollutants and vehicle groups, cold start inclusive CAERs are higher than the corresponding CLs and as high as the standards. The CLs, which are based on standard driving cycles, tend to underestimate real-world emission rates. Therefore, emission inventory estimates using certification test results are potentially underestimated. Copyright © 2017 Elsevier B.V. All rights reserved.

Observing Human-induced Linkages between Urbanization and Earth's Climate System

NASA Technical Reports Server (NTRS)

Shepherd, J. Marshall; Jin, Menglin

2004-01-01

Urbanization is one of the extreme cases of land use change. Most of world s population has moved to urban areas. Although currently only 1.2% of the land is considered urban, the spatial coverage and density of cities are expected to rapidly increase in the near future. It is estimated that by the year 2025, 60% of the world s population will live in cities. Human activity in urban environments also alters atmospheric composition; impacts components of the water cycle; and modifies the carbon cycle and ecosystems. However, our understanding of urbanization on the total Earth-climate system is incomplete. Better understanding of how the Earth s atmosphere-ocean-land-biosphere components interact as a coupled system and the influence of the urban environment on this climate system is critical. The goal of the 2003 AGU Union session Human-induced climate variations on urban areas: From observations to modeling was to bring together scientists from interdisciplinary backgrounds to discuss the data, scientific approaches and recent results on observing and modeling components of the urban environment with the intent of sampling our current stand and discussing future direction on this topic. Herein, a summary and discussion of the observations component of the session are presented.

Linkages between the Urban Environment and Earth's Climate System

NASA Technical Reports Server (NTRS)

Shepherd, J. Marshall; Jin, Menglin

2003-01-01

Urbanization is one of the extreme cases of land use change. Although currently only 1.2% of the land is considered urban, the spatial coverage and density of cities are expected to rapidly increase in the near future. It is estimated that by the year 2025 60% of the world s population will live in cities (UNFP, 1999). Though urban areas are local in scale, human activity in urban environments has impacts at local, to global scale by changing atmospheric composition; impacting components of the water cycle; and modifying the carbon cycle 2nd ecosystems. For example, urban dwellers are undoubtedly familiar with "high" ozone pollution days, flash flooding in city streets, or heat stress on summer days. However, our understanding of urbanization on the total Earth-climate system is incomplete. Better understanding of how the Earth s weather, oceans, and land work together and the influence of the urban environment on this climate system is critical. This paper highlights some of the major and current issues involving interactions between urban environments and the Earth's climate system. It also captures some of the most current thinking and findings of the authors and key experts in the field.

An Ecohydrologic Model for a Shallow Groundwater Urban Environment

EPA Science Inventory

The urban environment is a patchwork of natural and artificial surfaces that results in complex interactions with and impacts to natural hydrologic cycles. Evapotranspiration (ET) is a major hydrologic flow that is often altered from urbanization, though the mechanisms of change ...

Investigation of dynamic driving cycle effect on the degradation of proton exchange membrane fuel cell by segmented cell technology

NASA Astrophysics Data System (ADS)

Lin, R.; Xiong, F.; Tang, W. C.; Técher, L.; Zhang, J. M.; Ma, J. X.

2014-08-01

Durability is one of the most important limiting factors for the commercialization of proton exchange membrane fuel cell (PEMFC). Fuel cells are more vulnerable to degradation under operating conditions as dynamic load cycle or start up/shut down. The purpose of this study is to evaluate influences of driving cycles on the durability of fuel cells through analyzing the degradation mechanism of a segmented cell in real time. This study demonstrates that the performance of the fuel cell significantly decreases after 200 cycles. The segmented cell technology is used to measure the local current density distribution, which shows that the current density at the exit region and the inlet region declines much faster than the other parts. Meanwhile, electro-chemical impedance spectroscopy (EIS) reveals that after 200 cycles the ohmic resistance of fuel cell increases, especially at the cathode, and electro-chemical surface area (ESA) decreases from 392 to 307 cm2 mg-1. Furthermore, scanning electron microscopy (SEM) images of the membrane-electrode assembly (MEA) in cross-section demonstrate crackle flaw on the surface of the catalyst layer and the delamination of the electrodes from the membrane. Transmission electron microscope (TEM) results also show that the Pt particle size increases distinctly after driving cycles.

The driving forces of land change in the Northern Piedmont of the United States

USGS Publications Warehouse

Auch, Roger F.; Napton, Darrell E.; Kambly, Steven; Moreland, Thomas R.; Sayler, Kristi L.

2012-01-01

Driving forces facilitate or inhibit land-use/land-cover change. Human driving forces include political, economic, cultural, and social attributes that often change across time and space. Remotely sensed imagery provides regional land-change data for the Northern Piedmont, an ecoregion of the United States that continued to urbanize after 1970 through conversion of agricultural and forest land covers to developed uses. Eight major driving forces facilitated most of the land conversion; other drivers inhibited or slowed change. A synergistic web of drivers may be more important in understanding land change than individual drivers by themselves.

Urban infrastructure and longitudinal stream profiles

NASA Astrophysics Data System (ADS)

Lindner, G. A.; Miller, A. J.

2009-12-01

Urban streams usually are highly engineered or modified by human activity and are conventionally thought of as being geometrically, and thus hydraulically, simple. The work presented here, a contribution to NSF CNH Project 0709659, is designed to capture the influence of urban infrastructure on the character of longitudinal profiles and flow hydraulics along streams in the Baltimore metropolitan area. Detailed topographic data sets are derived from LiDAR supplemented by total-station surveys of the channel bed and low-flow water surface. These in turn are used to drive 2D depth-averaged hydraulic models comparing flow conditions over a range of urban development patterns and stormwater management regimes. Results from stream surveys of 1-2 km length indicate that channels in older, highly urbanized areas typically have straight planforms and strongly stepped profiles characterized by a series of deep, stagnant pools with short intervening riffles or runs. This pattern is associated with frequent interruption of the channel profile by bridges, culverts, road embankments and other artificial structures. In one survey reach of the Dead Run watershed, 50 percent of cumulative channel length has zero gradient at low flow, and 50 percent of cumulative head loss is accounted for by only 4 percent of channel length. In the suburban Red Run watershed recent development has occurred under strict stormwater management regulations with minimal encroachment on the riparian zone. Although their average gradients are similar, the Red Run survey reach is steeper than the Dead Run reach over most its length but has a smaller fraction of total head loss caused by local slope breaks. Modeling results indicate that these differences in stream morphology are associated with differences in velocity, flow pattern, and residence time at base flow; the stepped nature of the profile in the older urban area becomes less pronounced at intermediate to high flows, but the controlling influence of infrastructure may become dominant again during large floods. Because flashy urban streams have lower and more persistent low flows as well as more extreme flood flows, these hydraulic patterns may have implications for both biogeochemical cycling at base flow and transport and deposition of sediment and other constituents during flood periods. Continuing research will develop a typology of urban streams in terms of the influence of engineering practices on flow patterns and material transport.

Oscillatory nonohomic current drive for maintaining a plasma current

DOEpatents

Fisch, N.J.

1984-01-01

Apparatus and methods are described for maintaining a plasma current with an oscillatory nonohmic current drive. Each cycle of operation has a generation period in which current driving energy is applied to the plasma, and a relaxation period in which current driving energy is removed. Plasma parameters, such as plasma temperature or plasma average ionic charge state, are modified during the generation period so as to oscillate plasma resistivity in synchronism with the application of current driving energy. The invention improves overall current drive efficiencies.

Oscillatory nonhmic current drive for maintaining a plasma current

DOEpatents

Fisch, Nathaniel J.

1986-01-01

Apparatus and method of the invention maintain a plasma current with an oscillatory nonohmic current drive. Each cycle of operation has a generation period in which current driving energy is applied to the plasma, and a relaxation period in which current driving energy is removed. Plasma parameters, such as plasma temperature or plasma average ionic charge state, are modified during the generation period so as to oscillate plasma resistivity in synchronism with the application of current driving energy. The invention improves overall current drive efficiencies.

Safe and Autonomous Drones for Urban Flight

NASA Technical Reports Server (NTRS)

Krishnakumar, Kalmanje

2016-01-01

Autonomous vehicles are no longer futuristic technology; in fact, there are already cars with self-driving features on the road. Over the next five years, the connected vehicles will disrupt the entire automotive and UAS ecosystems. The industry will undergo fundamental change as semi-autonomous driving and flying emerges, followed by an eventual shift to full autonomy.

Spatial variation of air quality index and urban driving factors linkages: evidence from Chinese cities.

PubMed

Pu, Haixia; Luo, Kunli; Wang, Pin; Wang, Shaobin; Kang, Shun

2017-02-01

Daily air quality index (AQI) of 161 Chinese cities obtained from the Ministry of Environmental Protection of China in 2015 is conducted. In this study, to better explore spatial distribution and regional characteristic of AQI, global and local spatial autocorrelation is utilized. Pearson's correlation is introduced to determine the influence of single urban indicator on AQI value. Meanwhile, multiple linear stepwise regression is chosen to estimate quantitatively the most influential urban indicators on AQI. The spatial autocorrelation analysis indicates that the AQI value of Chinese 161 cities shows a spatial dependency. Higher AQI is mainly located in north and northwest regions, whereas low AQI is concentrated in the south and the Qinghai-Tibet regions. The low AQI and high AQI values in China both exhibit relative immobility through seasonal variation. The influence degree of three adverse urban driving factors on AQI value is ranked from high to low: coal consumption of manufacturing > building area > coal consumption of the power industry. It is worth noting that the risk of exposed population to poor quality is greater in the northern region than in other regions. The results of the study provide a reference for the formulation of urban policy and improvement of air quality in China.

Substance Use in Urban and Rural Texas School Districts

ERIC Educational Resources Information Center

Maxwell, Jane Carlisle; Tackett-Gibson, Melissa; Dyer, James

2006-01-01

The aim of this study is to compare substance use between urban and rural secondary school districts in Texas between 1998 and 2003. The differences were analyzed using chi-square and analysis of variance. The analysis found that rural schools had students who reported higher rates of use of tobacco, frequent binge drinking, and driving while…

A multi-scalar approach to theorizing socio-ecological dynamics of urban residential landscapes

Treesearch

Rinku Roy Chowdhury; Kelli Larson; Morgan Grove; Colin Polsky; Elizabeth Cook; Jeffrey Onsted; Laura Ogden

2011-01-01

Urban residential expansion increasingly drives land use, land cover and ecological changes worldwide, yet social science theories explaining such change remain under-developed. Existing theories often focus on processes occurring at one scale, while ignoring other scales. Emerging evidence from four linked U.S. research sites suggests it is essential to examine...

Striker Suitability Challenges in a Complex Threat Environment

DTIC Science & Technology

2008-04-23

áåÑçêãÉÇ=ÅÜ~åÖÉ=======- 163 - = = large number of wheel spindles developed fatigue cracks and had to be replaced early. Drive shafts are also failing... spindles developing fatigue cracks – drive shafts breaking – prescribed tire pressure is 80 PSI, however, with slat armor/sandbags – must maintain...drive shafts , differentials – Impairs off-road ops, larger footprint • Though not designed primarily for the urban fight (MOUT), Stryker is well-suited

Energy analysis of electric vehicles using batteries or fuel cells through well-to-wheel driving cycle simulations

NASA Astrophysics Data System (ADS)

Campanari, Stefano; Manzolini, Giampaolo; Garcia de la Iglesia, Fernando

This work presents a study of the energy and environmental balances for electric vehicles using batteries or fuel cells, through the methodology of the well to wheel (WTW) analysis, applied to ECE-EUDC driving cycle simulations. Well to wheel balances are carried out considering different scenarios for the primary energy supply. The fuel cell electric vehicles (FCEV) are based on the polymer electrolyte membrane (PEM) technology, and it is discussed the possibility to feed the fuel cell with (i) hydrogen directly stored onboard and generated separately by water hydrolysis (using renewable energy sources) or by conversion processes using coal or natural gas as primary energy source (through gasification or reforming), (ii) hydrogen generated onboard with a fuel processor fed by natural gas, ethanol, methanol or gasoline. The battery electric vehicles (BEV) are based on Li-ion batteries charged with electricity generated by central power stations, either based on renewable energy, coal, natural gas or reflecting the average EU power generation feedstock. A further alternative is considered: the integration of a small battery to FCEV, exploiting a hybrid solution that allows recovering energy during decelerations and substantially improves the system energy efficiency. After a preliminary WTW analysis carried out under nominal operating conditions, the work discusses the simulation of the vehicles energy consumption when following standardized ECE-EUDC driving cycle. The analysis is carried out considering different hypothesis about the vehicle driving range, the maximum speed requirements and the possibility to sustain more aggressive driving cycles. The analysis shows interesting conclusions, with best results achieved by BEVs only for very limited driving range requirements, while the fuel cell solutions yield best performances for more extended driving ranges where the battery weight becomes too high. Results are finally compared to those of conventional internal combustion engine vehicles, showing the potential advantages of the different solutions considered in the paper and indicating the possibility to reach the target of zero-emission vehicles (ZEV).

Strengthening Carbon Sinks in Urban Soils to Mitigate and Adapt to Climate Change (Invited)

NASA Astrophysics Data System (ADS)

Lorenz, K.

2010-12-01

Urban lands comprise the most intensively transformed lands on earth. Urban land cover changed from 0.01% of the global ice-free land area in 1700 to 0.5% in 2002. Globally, urbanization is now the primary process of land cover transformation. Urbanization accentuates conversion of natural or agricultural lands to urban soils with altered biological, chemical and physical properties. Soil functions particularly important in urban ecosystems are the protection against damages by intense precipitation and flooding, retention and immobilization of contaminants, production of clean water, and buffering of climate extremes, mainly through evaporative cooling. Because of their disturbance by human activities, urban soils have distinct properties. In contrast to natural soils, human-made materials dominate or strongly influence urban soils as human activities constitute important soil-forming factors in urban ecosystems. Soils whose properties and pedogenesis are dominated by their technical origin are classified as Technosols in the World Reference Base (WRB) for Soil Resources. They contain large proportions of artifacts, or are sealed by technic hard rock. Technosols include soils from wastes (e.g., landfills, sludge, cinders, mine spoils and ashes), pavements with their underlying unconsolidated materials, soils with geomembranes and constructed soils in human-made materials. However, Technosols and their properties have not yet been studied extensively. Yet, a greater understanding of urban soil properties is urgently needed to assess their biogeochemical cycles and role in the global carbon (C) cycle, and to manage their ecosystem services for the well-being of the urban population. Studies of biogeochemical cycles in urban soils of Stuttgart, Germany, have shown that soils from as deep as 1.9-m depth contain significant amounts of microbial biomass and are metabolically active. Buried organic matter (OM) rich artifacts where frequently observed originating from a long industrial history and devastations during World War II. In most surface soils in Stuttgart, however, OM was dominated by plant litter derived compounds but in one urban soil anthropogenic OM and black carbon (BC) dominated soil organic carbon (SOC) as indicated by bloch decay solid-state 13C nuclear magnetic resonance (NMR) spectroscopy. Artifacts such as municipal solid waste, construction waste, and fragments of charcoal, coal and glass were also found in urban forest soil profiles to 1-m depth in Columbus, OH. To this depth, about 150 Mg SOC ha-1 were stored and, thus, more than in urban forest soils of Baltimore, MD, and New York City, NY. However, the contribution of litter derived vs. artifact derived OM compounds such as BC has not been assessed for urban soils in the U.S.. In summary, studies on biogeochemical cycles in urban ecosystems must include the entire soil profile as anthropogenic activities may create Technosols with properties not encountered in soils of natural ecosystems. As urban ecosystems are major sources of atmospheric carbon dioxide (CO2), Technosols may be tailor-made to imitate natural soils with high SOC pools and long carbon mean residence times. Thus, the C sink in urban soils must be strengthened to mitigate and adapt urban ecosystems to abrupt climate change.

Carbon Storage in Urban Areas in the USA

NASA Astrophysics Data System (ADS)

Churkina, G.; Brown, D.; Keoleian, G.

2007-12-01

It is widely accepted that human settlements occupy a small proportion of the landmass and therefore play a relatively small role in the dynamics of the global carbon cycle. Most modeling studies focusing on the land carbon cycle use models of varying complexity to estimate carbon fluxes through forests, grasses, and croplands, but completely omit urban areas from their scope. Here, we estimate carbon storage in urban areas within the United States, defined to encompass a range of observed settlement densities, and its changes from 1950 to 2000. We show that this storage is not negligible and has been continuously increasing. We include natural- and human-related components of urban areas in our estimates. The natural component includes carbon storage in urban soil and vegetation. The human related component encompasses carbon stored long term in buildings, furniture, cars, and waste. The study suggests that urban areas should receive continued attention in efforts to accurately account for carbon uptake and storage in terrestrial systems.

Urbanization effects on soil nitrogen transformations and microbial biomass in the subtropics

Treesearch

Heather A. Enloe; B. Graeme Lockaby; Wayne C. Zipperer; Greg L. Somers

2015-01-01

As urbanization can involve multiple alterations to the soil environment, it is uncertain how urbanization effects soil nitrogen cycling. We established 22–0.04 ha plots in six different land cover types—rural slash pine (Pinus elliottii) plantations (n=3), rural natural pine forests (n=3), rural natural oak forests (n=4), urban pine forests (n=3), urban oak forests (n...

Collaboration essential for an energy neutral urban water cycle.

PubMed

Frijns, Jos; Mulder, Mirabella; Roorda, Jelle; Schepman, Hans; Voskamp, Tom

2013-01-01

Two Dutch water boards prepared a Master Plan with measures to substantially reduce their energy use by 2027. In total, more than 100 measures were identified such as bubble aeration and heat recovery from effluent. Together these measures result in a 90-95% reduction in energy use at the water boards. However, for the whole urban water cycle, thus including the energy required for warm water use in households, the total energy reduction from these measures at the water boards is only 5-6%. To attain the objective to have an energy neutral urban water cycle, collaboration with other sectors such as housing, energy, agriculture and industry will be essential. Active collaboration of the water boards through the incorporation of energy efficient water measures as part of the carbon neutral effort of cities is recognized to be a promising strategy.

Experimental research on safety impacts of the inside shoulder based on driving simulation.

PubMed

Zhao, Xiaohua; Ding, Han; Wu, Yiping; Ma, Jianming; Zhong, Liande

2015-03-01

Statistical data shows that single-vehicle crashes account for half of all traffic crashes on expressways in China, and previous research has indicated that main contributing factors were related to whether and how the inside shoulder was paved. The inside shoulder provides space for drivers to make evasive maneuvers and accommodate driver errors. However, lower-cost construction solutions in China have resulted in the design of numerous urban expressway segments that lack inside shoulders. This paper has two objectives. The first is to reveal the safety impacts of inside shoulders on urban expressways by driving simulator experiment. The second objective is to propose optimal range and recommended value of inside shoulder width for designing inside shoulders of urban expressways. The empirical data, including subjects' eye movement data, heart rate (HR) and the lateral position of vehicles, were collected in a driving simulator. The data were analyzed to evaluate the safety impacts of the inside shoulder. The results have revealed that the inside shoulder has an impact on drivers' visual perception, behaviors, and psychology; in particular, it has a significant effect on vehicle operations. In addition, this paper recommends the desired and optimal inside shoulder widths for eight-lane, two-way divided expressways. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Transportation Leapfrog: Using Smart Phones to Collect Driving Data and Model Fuel Economy in India

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

Gopal, Anand; Schewel, Laura; Saxena, Samveg

Car ownership in India is expected to skyrocket in the coming decades, strongly driven by rising incomes. This phenomenon provides unprecedented opportunities for automakers and equally unprecedented social and environmental challenges. Policymakers, urban planners and civil society see this car boom leading to an explosion in problems related to congestion, infrastructure, air pollution, safety, higher oil imports and climate change. For all these stakeholders to take effective action, good data on how people use their cars, their demand for mobility and their behavior in mobility is essential. Unfortunately, there is very little data on the Indian transport sector as amore » whole and virtually none on real-world vehicle performance and use. The rapid development of high quality mobile telecommunications infrastructure provides India with the opportunity to leapfrog the West in cheaply collecting vast amounts of useful data from transportation. In this paper, we describe a pilot project in which we use commercial smart phone apps to collect per second car driving data from the city of Pune, instantly upload it through 3G and prepare it for analysis using advanced noise filtering algorithms for less than $1 per day per car. We then use our data in an Autonomie simulation to show that India’s currently planned fuel economy test procedures will result in over-estimates of fuel economy of approximately 35% for a typical Indian car when it is operated in real world conditions. Supporting better driving cycle development is just one of many applications for smart phone derived data in Indian transportation.« less

Life cycle implications of urban green infrastructure.

PubMed

Spatari, Sabrina; Yu, Ziwen; Montalto, Franco A

2011-01-01

Low Impact Development (LID) is part of a new paradigm in urban water management that aims to decentralize water storage and movement functions within urban watersheds. LID strategies can restore ecosystem functions and reduce runoff loadings to municipal water pollution control facilities (WPCF). This research examines the avoided energy and greenhouse gas (GHG) emissions of select LID strategies using life cycle assessment (LCA) and a stochastic urban watershed model. We estimate annual energy savings and avoided GHG emissions of 7.3 GJ and 0.4 metric tons, respectively, for a LID strategy implemented in a neighborhood in New York City. Annual savings are small compared to the energy and GHG intensity of the LID materials, resulting in slow environmental payback times. This preliminary analysis suggests that if implemented throughout an urban watershed, LID strategies may have important energy cost savings to WPCF, and can make progress towards reducing their carbon footprint. Copyright © 2011 Elsevier Ltd. All rights reserved.

Mental health and poverty in the inner city.

PubMed

Anakwenze, Ujunwa; Zuberi, Daniyal

2013-08-01

Rapid urbanization globally threatens to increase the risk to mental health and requires a rethinking of the relationship between urban poverty and mental health. The aim of this article is to reveal the cyclic nature of this relationship: Concentrated urban poverty cultivates mental illness, while the resulting mental illness reinforces poverty. The authors used theories about social disorganization and crime to explore the mechanisms through which the urban environment can contribute to mental health problems. They present some data on crime, substance abuse, and social control to support their claim that mental illness reinforces poverty. The authors argue that, to interrupt this cycle and improve outcomes, social workers and policymakers must work together to implement a comprehensive mental health care system that emphasizes prevention, reaches young people, crosses traditional health care provision boundaries, and involves the entire community to break this cycle and improve the outcomes of those living in urban poverty.

A Review of Current Investigations of Urban-Induced Rainfall and Recommendations for the Future

NASA Technical Reports Server (NTRS)

Shepherd, J. Marshall

2004-01-01

Precipitation is a key link in the global water cycle and a proxy for changing climate; therefore proper assessment of the urban environment s impact on precipitation (land use, aerosols, thermal properties) will be increasingly important in ongoing climate diagnostics and prediction, Global Water and Energy Cycle (GWEC) analysis and modeling, weather forecasting, freshwater resource management, urban planning-design and land-atmosphere-ocean interface processes. These facts are particularly critical if current projections for global urban growth are accurate. The goal of this paper is to provide a concise review of recent (1990-present) studies related to how the urban environment affects precipitation. In addition to providing a synopsis of current work, recent findings are placed in context with historical investigations such as METROMEX studies. Both observational and modeling studies of urban-induced rainfall are discussed. Additionally, a discussion of the relative roles of urban dynamic and microphysical (e.g. aerosol) processes is presented. The paper closes with a set of recommendations for what observations and capabilities are needed in the future to advance our understanding of the processes.

Sustainability in urban water resources management - some notes from the field

NASA Astrophysics Data System (ADS)

Shuster, W.; Garmestani, A.; Green, O. O.

2014-12-01

Urban development has radically transformed landscapes, and along with it, how our cities and suburbs cycle energy and water. One unfortunate outcome of urbanization is the production of massive volumes of uncontrolled runoff volume. Our civic infrastructure is sometimes marginally capable of handling even dry-weather fluxes without wastewater system overflows, much less the challenges of wet-weather events. The predominance of runoff volume in urban water balance has had serious ramifications for regulatory activity, municipal financial matters, and public health. In the interest of protecting human health and the environment, my group's research has primarily addressed the integration of social equity, economic stabilization, and environmental management to underpin the development of sustainable urban water cycles. In this talk, I will present on: 1) the Shepherd Creek Stormwater Management project wherein an economic incentive was used to recruit citizen stormwater managers and distribute parcel-level, green infrastructure-based stormwater control measures; and 2) our urban soil pedologic-hydrologic assessment protocol that we use as a way of understanding the capacity for urban soils to provide ecosystem services, and in cities representing each of the major soil orders.

Influence of contrast morphogenetic features of urban constructed soils on the functioning of Moscow green lawn urban ecosystems: analysis based on the field model experiment

NASA Astrophysics Data System (ADS)

Epikhina, Anna; Vizirskaya, Mariya; Mazirov, Ilya; Vasenev, Vyacheslav; Vasenev, Ivan; Valentini, Riccardo

2014-05-01

Green lawns are the key element of the urban environment. They occupy a considerable part of the city area and locate in different urban functional zones. Urban constructed soils under green lawns have a unique spatial variability in chemical and morphogenetic features. So far, there is lack of information on the influence of morphogenetic features of urban soils on the functioning of the green lawn ecosystems especially in Moscow - the biggest megalopolis in Europe. Urban lawns perform a number of principal functions including both aesthetic and environmental. The role of the green lawn ecosystems in global carbon cycle is one of their main environmental functions. It is traditionally assessed through carbon stocks and fluxes in the basic ecosystem components. So far, such a data for the urban lawn ecosystems of the Moscow megapolis is lacking. In addition to environmental functions, green lawns perform an important ornamental role, which is also a critical criterion of their optimal functioning. Considering the variability of driving factors, influencing green lawns in urban environment, we carry out the model experiment in order to analyze "pure" effect of soil morphogenetic features. The current study aimed to analyze the influence of contrast morphogenetic features of urban constructed soils on the environmental and aesthetic functions of lawn ecosystems in Moscow megapolis basing in the model experiment. We carry out the model experiment located at the experimental field of the Russian State Agrarian University. Special transparent containers developed for the experiment, provided an option to observe soil morphogenetic features dynamics, including the depth and material of the organic transformation. At the same soil body inside the containers was united with the outside environment through the system of holes in the bottom and walls. The set of urban constructed soils includ four contrast types of the top soil (turf (T), turf-sand (TSa), turf-soil (TSo) and sand-soil (SS)) with three version of the depths (5, 10 and 20 cm). Soil construction with 10 cm organic horizon from TS top soil was taken as a reference. Grass mixture used for the green lawn including: Lolium perenne, Poa pratensis and Festuca rubra. For all the containers we measured soil CO2 emission by Li-820, soil temperature and moisture and the grass ornamental quality based on the 30-score scale (Laptev; 1988). All the measurements have been done in June-October 2013 with two-week time steps. We also observed the dynamic in soil chemical features (Corg, Ntot and pHKCl) monthly. We found high seasonal dynamics for all the observed functioning parameters. The highest CO2 emission was obtained in the beginning of July, whereas the lowest one - at the end of August. Maximal averaged CO2 emission was shown for the TSa and TSo substrates with the 20 cm depth. The lowest flux has been fixed for the more mineralized substrat. Soil moisture was shown as the main driving factor influencing CO2 emission both for the seasonal dynamics and for the averaged values for different substrates and depths (r=0.5, p<0.05). As for the aesthetic function the highest grass ornamental quality was shown for 20 cm TS and 5 cm T substrate (30 scores), whereas the lowest one was obtained for SS substrate with 5 and 20 cm depths (5 scores). We also obtained high positive correlation between the grass ornamental quality and the CO2 emissions (r=0.84, p>0.05). This outcome highlights that the standards of urban constructed soils' optimal features should be the compromise between the beauty of the green lawn and climate mitigation demands. Supported by the RF governmental grant 11.G34.31.0079

Optimal capacity design of LID facility for conserving natural water cycle and its sensitivity analysis

NASA Astrophysics Data System (ADS)

Lee, O.; Choi, J.; Lee, J.; Kim, S.

2017-12-01

Since the 20th century, urbanization has resulted in increased impermeable land surface and reduced infiltration capacity in catchment scale. Especially, when agriculture area or forest area would be developed into urban area, it can cause more runoff in the same climate condition. Such urbanization causes problems such as changes in hydrological cycle and ecosystem disturbance. Various methods have been proposed worldwide to reduce the impact of such urbanization. Among the various strategies, the low-impact development is a development strategy that aims to return to pre-development state by minimizing the change of the hydrological cycle due to urbanization. In this strategy, the infiltration and/or surface storage of stormwater runoff can be increased through the installation of various facilities. In this study, a facility capacity design strategy is proposed to return into the natural water cycle through the installation of various LID facilities. This is accomplished by determining the optimal LID facility design capacity through which flow duration curves remain the same before and after urban development. For this purpose, EPA-SWMM is constructed with a part of Busan Metropolitan City Noksan Industrial Complex as a virtual processing area. Under the various land-use scenarios, the optimum design capacity of various LID facilities capable of retaining the flow duration curve before and after development is determined. In addition, the sensitivity of the optimal design capacity of LID facilities is analyzed according to the design specifications of various LID facilities, the local rainfall characteristics, and the size of the treatment area. Acknowledgement This research was supported by a grant (2016000200002) from Public Welfare Technology Development Program funded by Ministry of Environment of Korean government.

Emergence of evolutionary cycles in size-structured food webs.

PubMed

Ritterskamp, Daniel; Bearup, Daniel; Blasius, Bernd

2016-11-07

The interplay of population dynamics and evolution within ecological communities has been of long-standing interest for ecologists and can give rise to evolutionary cycles, e.g. taxon cycles. Evolutionary cycling was intensely studied in small communities with asymmetric competition; the latter drives the evolutionary processes. Here we demonstrate that evolutionary cycling arises naturally in larger communities if trophic interactions are present, since these are intrinsically asymmetric. To investigate the evolutionary dynamics of a trophic community, we use an allometric food web model. We find that evolutionary cycles emerge naturally for a large parameter ranges. The origin of the evolutionary dynamics is an intrinsic asymmetry in the feeding kernel which creates an evolutionary ratchet, driving species towards larger bodysize. We reveal different kinds of cycles: single morph cycles, and coevolutionary and mixed cycling of complete food webs. The latter refers to the case where each trophic level can have different evolutionary dynamics. We discuss the generality of our findings and conclude that ongoing evolution in food webs may be more frequent than commonly believed. Copyright © 2016 Elsevier Ltd. All rights reserved.

Changes in land use driven by urbanization impact nitrogen cycling and the microbial community composition in soils

NASA Astrophysics Data System (ADS)

Wang, Haitao; Marshall, Christopher W.; Cheng, Minying; Xu, Huijuan; Li, Hu; Yang, Xiaoru; Zheng, Tianling

2017-03-01

Transition of populations from rural to urban living causes landscape changes and alters the functionality of soil ecosystems. It is unclear how this urbanization disturbs the microbial ecology of soils and how the disruption influences nitrogen cycling. In this study, microbial communities in turfgrass-grown soils from urban and suburban areas around Xiamen City were compared to microbial communities in the soils from rural farmlands. The potential N2O emissions, potential denitrification activity, and abundances of denitrifiers were higher in the rural farmland soils compared with the turfgrass soils. Ammonia oxidizing archaea (AOA) were more abundant than ammonia oxidizing bacteria (AOB) in turfgrass soils. Within turfgrass soils, the potential nitrification activities and AOA abundances were higher in the urban than in the suburban soils. These results indicate a more pivotal role of AOA in nitrification, especially in urban soils. Microbial community composition was distinctly grouped along urbanization categories (urban, suburban, and rural) classified according to the population density, which can in part be attributed to the differences in soil properties. These observed changes could potentially have a broader impact on soil nutrient availability and greenhouse gas emissions.

Development and application of a new grey dynamic hierarchy analysis system (GDHAS) for evaluating urban ecological security.

PubMed

Shao, Chaofeng; Tian, Xiaogang; Guan, Yang; Ju, Meiting; Xie, Qiang

2013-05-21

Selecting indicators based on the characteristics and development trends of a given study area is essential for building a framework for assessing urban ecological security. However, few studies have focused on how to select the representative indicators systematically, and quantitative research is lacking. We developed an innovative quantitative modeling approach called the grey dynamic hierarchy analytic system (GDHAS) for both the procedures of indicator selection and quantitative assessment of urban ecological security. Next, a systematic methodology based on the GDHAS is developed to assess urban ecological security comprehensively and dynamically. This assessment includes indicator selection, driving force-pressure-state-impact-response (DPSIR) framework building, and quantitative evaluation. We applied this systematic methodology to assess the urban ecological security of Tianjin, which is a typical coastal super megalopolis and the industry base in China. This case study highlights the key features of our approach. First, 39 representative indicators are selected for the evaluation index system from 62 alternative ones available through the GDHAS. Second, the DPSIR framework is established based on the indicators selected, and the quantitative assessment of the eco-security of Tianjin is conducted. The results illustrate the following: urban ecological security of Tianjin in 2008 was in alert level but not very stable; the driving force and pressure subsystems were in good condition, but the eco-security levels of the remainder of the subsystems were relatively low; the pressure subsystem was the key to urban ecological security; and 10 indicators are defined as the key indicators for five subsystems. These results can be used as the basis for urban eco-environmental management.

Development and Application of a New Grey Dynamic Hierarchy Analysis System (GDHAS) for Evaluating Urban Ecological Security

PubMed Central

Shao, Chaofeng; Tian, Xiaogang; Guan, Yang; Ju, Meiting; Xie, Qiang

2013-01-01

Selecting indicators based on the characteristics and development trends of a given study area is essential for building a framework for assessing urban ecological security. However, few studies have focused on how to select the representative indicators systematically, and quantitative research is lacking. We developed an innovative quantitative modeling approach called the grey dynamic hierarchy analytic system (GDHAS) for both the procedures of indicator selection and quantitative assessment of urban ecological security. Next, a systematic methodology based on the GDHAS is developed to assess urban ecological security comprehensively and dynamically. This assessment includes indicator selection, driving force-pressure-state-impact-response (DPSIR) framework building, and quantitative evaluation. We applied this systematic methodology to assess the urban ecological security of Tianjin, which is a typical coastal super megalopolis and the industry base in China. This case study highlights the key features of our approach. First, 39 representative indicators are selected for the evaluation index system from 62 alternative ones available through the GDHAS. Second, the DPSIR framework is established based on the indicators selected, and the quantitative assessment of the eco-security of Tianjin is conducted. The results illustrate the following: urban ecological security of Tianjin in 2008 was in alert level but not very stable; the driving force and pressure subsystems were in good condition, but the eco-security levels of the remainder of the subsystems were relatively low; the pressure subsystem was the key to urban ecological security; and 10 indicators are defined as the key indicators for five subsystems. These results can be used as the basis for urban eco-environmental management. PMID:23698700

On-line monitoring of benzene air concentrations while driving in traffic by means of isotopic dilution gas chromatography/mass spectrometry.

PubMed

Davoli, E; Cappellini, L; Moggi, M; Ferrari, S; Fanelli, R

1996-01-01

There is no shortage of information about the average benzene concentrations in urban air, but there is very little about microenvironmental exposure, such as in-vehicle concentrations while driving in various traffic conditions, while refuelling, or while in a parking garage. The main reason for this lack of data is that no analytical instrumentation has been available to measure on-line trace amounts of benzene in such situations. We have recently proposed a highly accurate, high-speed cryofocusing gas chromatography/mass spectrometry (GC/MS) system for monitoring benzene concentrations in air. Accuracy of the analytical data is achieved by enrichment of the air sample before trapping, with a stable isotope permeation tube system. The same principles have been applied to a new instrument, specifically designed for operation on an electric vehicle (Ducato Elettra, Fiat). The zero emission vehicle and the fully transportable, battery-operated GC/MS system provide a unique possibility of monitoring benzene exposure in real everyday situations such as while driving, refuelling, or repairing a car. All power consumptions have been reduced so as to achieve a battery-operated GC/MS system. Liquid nitrogen cryofocusing has been replaced by a packed, inductively heated, graphitized charcoal microtrap. The instrument has been mounted on shock absorbers and installed in the van. The whole system has been tested in both fixed and mobile conditions. The maximum monitoring period without external power supply is 6 h. The full analytical cycle is 4 min, allowing close to real-time monitoring, and the minimum detectable level is 1 microgram/m3 for benzene. In-vehicle monitoring showed that, when recirculation was off and ventilation on, i.e., air from outside the vehicle was blown inside, concentrations varied widely in different driving conditions: moving from a parking lot into normal traffic on an urban traffic condition roadway yielded an increase in benzene concentration from 17 to 62.3 micrograms/m3 even if the actual distance was small. A larger increase was observed when a car was left with the engine running at a distance 2 m from the zero emission vehicle: We measured an increment of benzene concentrations from 15.2 to 174.4 micrograms/m3 with a car equipped with a catalytic converter, and from 19.1 to 386.3 micrograms/m3 with a car without such a converter.

24 CFR 941.101 - Purpose and scope.

Code of Federal Regulations, 2010 CFR

2010-04-01

... housing residents over the long term and have the lowest possible life cycle costs, taking into account... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Purpose and scope. 941.101 Section 941.101 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued...

The Megafauna: People of the Urban Ecosystem.

ERIC Educational Resources Information Center

Petit, Jack; Gangloff, Deborah

1995-01-01

Addresses the need to make urban forestry information and resources available and understandable to everyone in an effort to organize and educate communities. The seemingly hidden aspects of the urban ecosystem are examined; and a sidebar looks at the air, carbon, and energy cycles and sustaining quality of life, in particular. (LZ)

A Case Study of the Perceptions of School Principals Regarding the Micropolitics of Consolidating Public Schools

ERIC Educational Resources Information Center

Slade, Darrin Andre

2012-01-01

The continued decline of many of America's urban centers has created a myriad of challenges for struggling inner city school systems. As the ills of society drive magnitudes of inner city residents into the suburbs many urban school districts must deal with the challenges of decreasing student enrollment and underused facilities. Many states…

Big Data | Transportation Research | NREL

Science.gov Websites

Designs Leveraging Fleet DNA data to characterize real-world duty cycles for urban delivery vehicles, NREL -extended electric vehicles for urban delivery applications, targeting efficiency improvements of 50

Understanding the visual skills and strategies of train drivers in the urban rail environment.

PubMed

Naweed, Anjum; Balakrishnan, Ganesh

2014-01-01

Due to the growth of information in the urban rail environment, there is a need to better understand the ergonomics profile underpinning the visual behaviours in train drivers. The aim of this study was to examine the tasks and activities of urban/metropolitan passenger train drivers in order to better understand the nature of the visual demands in their task activities. Data were collected from 34 passenger train drivers in four different Australian states. The research approach used a novel participative ergonomics methodology that fused interviews and observations with generative tools. Data analysis was conducted thematically. Results suggested participants did not so much drive their trains, as manage the intensity of visually demanding work held in their environment. The density of this information and the opacity of the task, invoked an ergonomics profile more closely aligned with diagnostic and error detection than actual train regulation. The paper discusses the relative proportion of strategies corresponding with specific tasks, the visual-perceptual load in substantive activities, and the requisite visual skills behoving navigation in the urban rail environment. These findings provide the basis for developing measures of complexity to further specify the visual demands in passenger train driving.

Identification of differences between rural and urban safety cultures.

PubMed

Rakauskas, Michael E; Ward, Nicholas J; Gerberich, Susan G

2009-09-01

The prevailing risk of traffic fatalities is much larger in rural areas compared to urban areas. A number of explanations have been offered to explain this including road design, emergency medical service proximity, and human factors. This research explored the potential contribution of rural driver attitudes that may underlie the increased fatal crash risk in rural environments. This analysis examined differences between rural and urban drivers in terms of self-reported risk taking for driving behaviors associated with fatal crashes and attitudes toward safety interventions using a large-scale survey. The results suggested that rural drivers engage in riskier behavior, such as not wearing seatbelts, because they have lower perceptions of the risks associated with such behaviors. Results also suggested that vehicle type (e.g., pickup trucks versus passenger vehicles) may be related to seatbelt compliance and frequency of driving under the influence of alcohol. Rural drivers perceived the utility of government-sponsored traffic safety interventions to be lower than their urban counterparts. This study provides insights into the role of the human factor in rural fatal crashes and provides policy suggestions for developing safety interventions that are designed with respect to the psychosocial factors that define the rural culture.

Importance of CME Radial Expansion on the Ability of Slow CMEs to Drive Shocks

NASA Astrophysics Data System (ADS)

Lugaz, N.; Farrugia, C. J.; Winslow, R. M.; Small, C. R.; Manion, T.; Savani, N.

2017-12-01

Coronal mass ejections (CMEs) may disturb the solar wind either by overtaking it, or by expanding into it, or both. CMEs whose front moves faster in the solar wind frame than the fast magnetosonic speed, drive shocks. In general, near 1 AU, CMEs with speed greater than about 500 km s-1 drive shocks, whereas slower CMEs do not. However, CMEs as slow as 350 km s-1 may sometimes, although rarely, drive shocks. Here, we study these slow CMEs with shocks and investigate the importance of CME expansion in contributing to their ability to drive shocks and in enhancing shock strength. Our focus is on CMEs with average speeds under 375 km s-1. From Wind measurements from 1996 to 2016, we find 22 cases of such shock-driving slow CMEs, and, for about half of them, the existence of the shock appears to be strongly related to CME expansion. We also investigate the proportion of all CMEs with speeds under 500 km s-1 with and without shocks in solar cycles 23 and 24, depending on their speed. We find no systematic difference, as might have been expected on the basis of the lower solar wind and Alfven speeds reported for solar cycle 24 vs. 23. The slower expansion speed of CMEs in solar cycle 24 is a reasonable explanation for this lack of increased frequency of shocks, but further studies are required.

Wastewater treatment and reuse in urban agriculture: exploring the food, energy, water, and health nexus in Hyderabad, India

NASA Astrophysics Data System (ADS)

Miller-Robbie, Leslie; Ramaswami, Anu; Amerasinghe, Priyanie

2017-07-01

Nutrients and water found in domestic treated wastewater are valuable and can be reutilized in urban agriculture as a potential strategy to provide communities with access to fresh produce. In this paper, this proposition is examined by conducting a field study in the rapidly developing city of Hyderabad, India. Urban agriculture trade-offs in water use, energy use and GHG emissions, nutrient uptake, and crop pathogen quality are evaluated, and irrigation waters of varying qualities (treated wastewater, versus untreated water and groundwater) are compared. The results are counter-intuitive, and illustrate potential synergies and key constraints relating to the food-energy-water-health (FEW-health) nexus in developing cities. First, when the impact of GHG emissions from untreated wastewater diluted in surface streams is compared with the life cycle assessment of wastewater treatment with reuse in agriculture, the treatment-plus-reuse case yields a 33% reduction in life cycle system-wide GHG emissions. Second, despite water cycling benefits in urban agriculture, only <1% of the nutrients are able to be captured in urban agriculture, limited by the small proportion of effluent divertible to urban agriculture due to land constraints. Thus, water treatment plus reuse in urban farms can enhance GHG mitigation and also directly save groundwater; however, very large amounts of land are needed to extract nutrients from dilute effluents. Third, although energy use for wastewater treatment results in pathogen indicator organism concentrations in irrigation water to be reduced by 99.9% (three orders of magnitude) compared to the untreated case, crop pathogen content was reduced by much less, largely due to environmental contamination and farmer behavior and harvesting practices. The study uncovers key physical, environmental, and behavioral factors that constrain benefits achievable at the FEW-health nexus in urban areas.

Response characteristic of high-speed on/off valve with double voltage driving circuit

NASA Astrophysics Data System (ADS)

Li, P. X.; Su, M.; Zhang, D. B.

2017-07-01

High-speed on/off valve, an important part of turbocharging system, its quick response has a direct impact on the turbocharger pressure cycle. The methods of improving the response characteristic of high speed on/off valve include increasing the magnetic force of armature and the voltage, decreasing the mass and current of coil. The less coil number of turns, the solenoid force is smaller. The special armature structure and the magnetic material will raise cost. In this paper a new scheme of double voltage driving circuit is investigated, in which the original driving circuit of high-speed on/off valve is replaced by double voltage driving circuit. The detailed theoretical analysis and simulations were carried out on the double voltage driving circuit, it showed that the switching time and delay time of the valve respectively are 3.3ms, 5.3ms, 1.9ms and 1.8ms. When it is driven by the double voltage driving circuit, the switching time and delay time of this valve are reduced, optimizing its response characteristic. By the comparison related factors (such as duty cycle or working frequency) about influences on response characteristic, the superior of double voltage driving circuit has been further confirmed.

Commercial viability of hybrid vehicles : best household use and cross national considerations.

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

Santini, D. J.; Vyas, A. D.

1999-07-16

Japanese automakers have introduced hybrid passenger cars in Japan and will soon do so in the US. In this paper, we report how we used early computer simulation model results to compare the commercial viability of a hypothetical near-term (next decade) hybrid mid-size passenger car configuration under varying fuel price and driving patterns. The fuel prices and driving patterns evaluated are designed to span likely values for major OECD nations. Two types of models are used. One allows the ''design'' of a hybrid to a specified set of performance requirements and the prediction of fuel economy under a number ofmore » possible driving patterns (called driving cycles). Another provides an estimate of the incremental cost of the hybrid in comparison to a comparably performing conventional vehicle. In this paper, the models are applied to predict the NPV cost of conventional gasoline-fueled vehicles vs. parallel hybrid vehicles. The parallel hybrids are assumed to (1) be produced at high volume, (2) use nickel metal hydride battery packs, and (3) have high-strength steel bodies. The conventional vehicle also is assumed to have a high-strength steel body. The simulated vehicles are held constant in many respects, including 0-60 time, engine type, aerodynamic drag coefficient, tire rolling resistance, and frontal area. The hybrids analyzed use the minimum size battery pack and motor to meet specified 0-60 times. A key characteristic affecting commercial viability is noted and quantified: that hybrids achieve the most pronounced fuel economy increase (best use) in slow, average-speed, stop-and-go driving, but when households consistently drive these vehicles under these conditions, they tend to travel fewer miles than average vehicles. We find that hours driven is a more valuable measure than miles. Estimates are developed concerning hours of use of household vehicles versus driving cycle, and the pattern of minimum NPV incremental cost (or benefit) of selecting the hybrid over the conventional vehicle at various fuel prices is illustrated. These results are based on data from various OECD motions on fuel price, annual miles of travel per vehicle, and driving cycles assumed to be applicable in those nations. Scatter in results plotted as a function of average speed, related to details of driving cycles and the vehicles selected for analysis, is discussed.« less

Report of an Urban Education Reform Experiment: Problems and Promise. Part I Project Development. Supplement to Final Report of the 5th Cycle Teacher Corps Project.

ERIC Educational Resources Information Center

Monroe, George E.

The Fifth Cycle Teacher Corps Project was undertaken by the University of Illinois at Chicago Circle to a) fulfill a stated mission of a university especially created to help resolve urban problems, b) find effective ways to help an inner-city community utilize its own resources, and c) conduct research on the effective uses of evaluation in…

Follicle-stimulating hormone levels in female workers exposed to urban pollutants.

PubMed

Ciarrocca, Manuela; Caciari, Tiziana; Ponticiello, Barnaba Giuseppina; Gioffrè, Pier Agostino; Tomei, Gianfranco; Sancini, Angela; Schifano, Maria Pia; Palermo, Paola; Nardone, Nadia; Scimitto, Lara; Fiaschetti, Maria; Tomei, Francesco

2011-12-01

The aim of this study was to evaluate if there were alterations in FSH plasma levels in female outdoor workers (traffic policewomen and drivers) exposed to chemical urban stressors vs. control group. After excluding subjects with main confounding factors, traffic policewomen, drivers and indoor workers were matched by age, working life, socioeconomic status, marital status, menstrual cycle day, age of menarche, habitual consumption of Italian coffee and soy. A total of 129 female subjects were included in the study: some 63 workers studied during proliferative phase and 66 during secretory phase of menstrual cycle. Proliferative phase of menstrual cycle: FSH mean values were significantly higher in traffic policewomen compared to controls (p < 0.05). Results suggest that in outdoor workers exposed to urban chemical stressors there are alterations in FSH levels; therefore FSH may be used as an early biological marker, valuable for the group, used in occupational set.

The role of multilevel factors in geographic differences in bicycle crash risk: a prospective cohort study

PubMed Central

2013-01-01

Background Regular cycling plays an important role in increasing physical activity levels but raises safety concerns for many people. While cyclists bear a higher risk of injury than most other types of road users, the risk differs geographically. Auckland, New Zealand’s largest urban region, has a higher injury risk than the rest of the country. This paper identified underlying factors at individual, neighbourhood and environmental levels and assessed their relative contribution to this risk differential. Methods The Taupo Bicycle Study involved 2590 adult cyclists recruited in 2006 and followed over a median period of 4.6 years through linkage to four national databases. The Auckland participants were compared with others in terms of baseline characteristics, crash outcomes and perceptions about environmental determinants of cycling. Cox regression modelling for repeated events was performed with multivariate adjustments. Results Of the 2554 participants whose addresses could be mapped, 919 (36%) resided in Auckland. The Auckland participants were less likely to be Māori but more likely to be socioeconomically advantaged and reside in an urban area. They were less likely to cycle for commuting and off-road but more likely to cycle in the dark and in a bunch, use a road bike and use lights in the dark. They had a higher risk of on-road crashes (hazard ratio: 1.47; 95% CI: 1.22, 1.76), of which 53% (95% CI: 20%, 72%) was explained by baseline differences, particularly related to cycling off-road, in the dark and in a bunch and residing in urban areas. They were more concerned about traffic volume, speed and drivers’ behaviour. Conclusions The excess crash risk in Auckland was explained by cycling patterns, urban residence and factors associated with the region’s car-dominated transport environment. PMID:24321134

Field chronobiology of a molluscan bivalve: how the moon and sun cycles interact to drive oyster activity rhythms.

PubMed

Tran, Damien; Nadau, Arnaud; Durrieu, Gilles; Ciret, Pierre; Parisot, Jean-Paul; Massabuau, Jean-Charles

2011-05-01

The present study reports new insights into the complexity of environmental drivers in aquatic animals. The focus of this study was to determine the main forces that drive mollusc bivalve behavior in situ. To answer this question, the authors continuously studied the valve movements of permanently immersed oysters, Crassostrea gigas, during a 1-year-long in situ study. Valve behavior was monitored with a specially build valvometer, which allows continuously recording of up to 16 bivalves at high frequency (10 Hz). The results highlight a strong relationship between the rhythms of valve behavior and the complex association of the sun-earth-moon orbital positions. Permanently immersed C. gigas follows a robust and strong behavior primarily driven by the tidal cycle. The intensity of this tidal driving force is modulated by the neap-spring tides (i.e., synodic moon cycle), which themselves depend of the earth-moon distance (i.e., anomalistic moon cycle). Light is a significant driver of the oysters' biological rhythm, although its power is limited by the tides, which remain the predominant driver. More globally, depending where in the world the bivalves reside, the results suggest their biological rhythms should vary according to the relative importance of the solar cycle and different lunar cycles associated with tide generation. These results highlight the high plasticity of these oysters to adapt to their changing environment.

SPECIATED VOC EMISSIONS FROM MODERN GDI LIGHT ...

EPA Pesticide Factsheets

Chassis dynamometer emissions testing was conducted to characterize speciated volatile organic compounds (VOCs), including mobile source air toxics (MSATs) and ozone precursors, in exhaust emissions from three modern gasoline direct injection (GDI) light-duty vehicles. Each GDI vehicle tested in this study utilized slightly different fuel injection technology: Vehicle 1 used a 2.4 liter, naturally aspirated, wall-guided GDI; Vehicle 2 used a 1.8 liter, turbocharged GDI engine; Vehicle 3 used a 1.5 liter, turbocharged, spray-guided GDI engine. Vehicle testing was conducted in a temperature controlled chassis dynamometer test cell at 22 °C over the EPA Federal Test Procedure (FTP) and a portion of the Supplemental FTP (SFTP). The FTP was conducted as a three phase cycle with a cold start, hot transient, and warm start phase (also known as the FTP-75 driving cycle). The SFTP consisted of the US06 driving cycle (conducted without the vehicle’s air conditioning on), which provides a more aggressive driving pattern than the FTP. The vehicles operated on 10 percent ethanol blended gasoline (E10). VOC emissions from diluted vehicle exhaust were sampled over each FTP phase and over the Supplemental FTP with SUMMA canisters for EPA Method TO-15 analysis and with DNPH cartridges for carbonyl analysis by EPA Method TO-11A. This presentation will report the impact of driving cycle and GDI technology on speciated MSAT emissions. MSAT emission rates will be compared

Accounting for the Variation of Driver Aggression in the Simulation of Conventional and Advanced Vehicles (Presentation)

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

Neubauer, J.; Wood, E.

2013-05-01

This presentation discusses a method of accounting for realistic levels of driver aggression to higher-level vehicle studies, including the impact of variation in real-world driving characteristics (acceleration and speed) on vehicle energy consumption and different powertrains (e.g., conventionally powered vehicles versus electrified drive vehicles [xEVs]). Aggression variation between drivers can increase fuel consumption by more than 50% or decrease it by more than 20% from average. The normalized fuel consumption deviation from average as a function of population percentile was found to be largely insensitive to powertrain. However, the traits of ideal driving behavior are a function of powertrain. Inmore » conventional vehicles, kinetic losses dominate rolling resistance and aerodynamic losses. In xEVs with regenerative braking, rolling resistance and aerodynamic losses dominate. The relation of fuel consumption predicted from real-world drive data to that predicted by the industry-standard HWFET, UDDS, LA92, and US06 drive cycles was not consistent across powertrains, and varied broadly from the mean, median, and mode of real-world driving. A drive cycle synthesized by NREL's DRIVE tool accurately and consistently reproduces average real-world for multiple powertrains within 1%, and can be used to calculate the fuel consumption effects of varying levels of driver aggression.« less

Modeling and predicting low-speed vehicle emissions as a function of driving kinematics.

PubMed

Hao, Lijun; Chen, Wei; Li, Lei; Tan, Jianwei; Wang, Xin; Yin, Hang; Ding, Yan; Ge, Yunshan

2017-05-01

An instantaneous emission model was developed to model and predict the real driving emissions of the low-speed vehicles. The emission database used in the model was measured by using portable emission measurement system (PEMS) under actual traffic conditions in the rural area, and the characteristics of the emission data were determined in relation to the driving kinematics (speed and acceleration) of the low-speed vehicle. The input of the emission model is driving cycle, and the model requires instantaneous vehicle speed and acceleration levels as input variables and uses them to interpolate the pollutant emission rate maps to calculate the transient pollutant emission rates, which will be accumulated to calculate the total emissions released during the whole driving cycle. And the vehicle fuel consumption was determined through the carbon balance method. The model predicted the emissions and fuel consumption of an in-use low-speed vehicle type model, which agreed well with the measured data. Copyright © 2016. Published by Elsevier B.V.

Urbanization, habitat loss, biodiversity decline:  solution pathways to break the cycle

Treesearch

Thomas Elmqvist; Wayne Zipperer; Burak  Güneralp

2016-01-01

The interactions between urbanization with biodiversity and ecosystem services that take place defy simple generalizations. There is increasing evidence for the negative impacts of urbanization on biodiversity, most directly in the form of habitat loss and fragmentation. Recent forecasts suggest that the amount of urban land near protected areas is expected to increase...

Alternative fuelds in urban fleets

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

Lindsay, T.

1994-12-31

In this presentation the author addresses four main objectives. They are to: discuss programs that are driving the introduction of alternative fuels into fleet operations in urban areas around the country; define alternative fuels; quantify the present use and future projections on alternative fuel vehicles (AVFs) in the Chicago metropolitan statistical area; and discuss benefits of increased use of alternative fuels in urban areas. Factors which touch on these points include: present domestic dependence on petroleum for autos, with usage exceeding production; the large populations in urban areas which do not meet Clean Air Standards; recent legislative initiatives which givemore » guidance and aid in the adoption of such strategies.« less

A Review of the Urban Development and Transport Impacts on Public Health with Particular Reference to Australia: Trans-Disciplinary Research Teams and Some Research Gaps

PubMed Central

Black, Deborah; Black, John

2009-01-01

Urbanization and transport have a direct effect on public health. A transdisciplinary approach is proposed and illustrated to tackle the general problem of these environmental stressors and public health. Processes driving urban development and environmental stressors are identified. Urbanization, transport and public health literature is reviewed and environmental stressors are classified into their impacts and which group is affected, the geographical scale and potential inventions. Climate change and health impacts are identified as a research theme. From an Australian perspective, further areas for research are identified. PMID:19543407

Urbanization effects on leaf litter decomposition, foliar nutrient dynamics and aboveground net primary productivity in the subtropics

Treesearch

Heather A. Enloe; B. Graeme Lockaby; Wayne C. Zipperer; Greg L. Somers

2015-01-01

Urbanization can alter nutrient cycling. This research evaluated how urbanization affected nutrient dynamics in the subtropics. We established 17–0.04 ha plots in five different land cover types—slash pine (Pinus elliottii) plantations (n=3), rural natural pine forests (n= 3), rural natural oak forests (n=4), urban pine forests (n=3) and urban oak forests (n=4) in the...

Life cycle assessments of urban water systems: a comparative analysis of selected peer-reviewed literature.

PubMed

Loubet, Philippe; Roux, Philippe; Loiseau, Eleonore; Bellon-Maurel, Veronique

2014-12-15

Water is a growing concern in cities, and its sustainable management is very complex. Life cycle assessment (LCA) has been increasingly used to assess the environmental impacts of water technologies during the last 20 years. This review aims at compiling all LCA papers related to water technologies, out of which 18 LCA studies deals with whole urban water systems (UWS). A focus is carried out on these 18 case studies which are analyzed according to criteria derived from the four phases of LCA international standards. The results show that whereas the case studies share a common goal, i.e., providing quantitative information to policy makers on the environmental impacts of urban water systems and their forecasting scenarios, they are based on different scopes, resulting in the selection of different functional units and system boundaries. A quantitative comparison of life cycle inventory and life cycle impact assessment data is provided, and the results are discussed. It shows the superiority of information offered by multi-criteria approaches for decision making compared to that derived from mono-criterion. From this review, recommendations on the way to conduct the environmental assessment of urban water systems are given, e.g., the need to provide consistent mass balances in terms of emissions and water flows. Remaining challenges for urban water system LCAs are identified, such as a better consideration of water users and resources and the inclusion of recent LCA developments (territorial approaches and water-related impacts). Copyright © 2014 Elsevier Ltd. All rights reserved.

Urbanization effects on climatic changes in 24 particular timings of the seasonal cycle in the middle and lower reaches of the Yellow River

NASA Astrophysics Data System (ADS)

Qian, Cheng; Ren, Guoyu; Zhou, Yaqing

2016-05-01

Changes in the timing of the seasonal cycle are important to natural ecosystems and human society, particularly agronomic activity. Urbanization effects (UEs) on surface air temperature changes at the local scale can be strong. Quantifying the observed changes in the timing of the seasonal cycle associated with UEs or large-scale background climatic warming is beneficial for the detection and attribution of regional climate change and for effective human adaptation, particularly in China, where rapid urbanization and industrialization are occurring. In this study, long-term changes in 24 particular timings of seasonal cycle, known as the Twenty-four Solar Terms (24STs), in the middle and lower reaches of the Yellow River in China are analyzed on the basis of homogenized daily temperature data over 1961-2010. UEs on these changes are further assessed by using a rural-station network selected from 2419 meteorological stations. In terms of area mean, half of the 24STs have significantly warmed, and UEs have contributed to 0.07-0.14 °C/decade or 25.7-64.0 % of the overall warming. The climatic solar terms from mid-February to early May (September and early October) have significantly advanced (delayed) by 5-17 days (approximately 5 days) over the last 50 years; 2-4 (2-3) of these days are attributed to UEs. The contribution of urbanization to the advancing or delaying trends is 21.7-69.5 %. The implications of these quantitative results differ for farmers, urban residents, and migrant workers in cities.

Zion National Park Propane-to-Electric Shuttle Bus Testing | Transportation

Science.gov Websites

storage requirements based on the fleet's unique operation. NREL will process and analyze the data using specialized tools-including the Drive-Cycle Rapid Investigation, Visualization, and Evaluation (DRIVE) tool

Development of a modular streamflow model to quantify runoff contributions from different land uses in tropical urban environments using Genetic Programming

NASA Astrophysics Data System (ADS)

Meshgi, Ali; Schmitter, Petra; Chui, Ting Fong May; Babovic, Vladan

2015-06-01

The decrease of pervious areas during urbanization has severely altered the hydrological cycle, diminishing infiltration and therefore sub-surface flows during rainfall events, and further increasing peak discharges in urban drainage infrastructure. Designing appropriate waster sensitive infrastructure that reduces peak discharges requires a better understanding of land use specific contributions towards surface and sub-surface processes. However, to date, such understanding in tropical urban environments is still limited. On the other hand, the rainfall-runoff process in tropical urban systems experiences a high degree of non-linearity and heterogeneity. Therefore, this study used Genetic Programming to establish a physically interpretable modular model consisting of two sub-models: (i) a baseflow module and (ii) a quick flow module to simulate the two hydrograph flow components. The relationship between the input variables in the model (i.e. meteorological data and catchment initial conditions) and its overall structure can be explained in terms of catchment hydrological processes. Therefore, the model is a partial greying of what is often a black-box approach in catchment modelling. The model was further generalized to the sub-catchments of the main catchment, extending the potential for more widespread applications. Subsequently, this study used the modular model to predict both flow components of events as well as time series, and applied optimization techniques to estimate the contributions of various land uses (i.e. impervious, steep grassland, grassland on mild slope, mixed grasses and trees and relatively natural vegetation) towards baseflow and quickflow in tropical urban systems. The sub-catchment containing the highest portion of impervious surfaces (40% of the area) contributed the least towards the baseflow (6.3%) while the sub-catchment covered with 87% of relatively natural vegetation contributed the most (34.9%). The results from the quickflow module revealed average runoff coefficients between 0.12 and 0.80 for the various land uses and decreased from impervious (0.80), grass on steep slopes (0.56), grass on mild slopes (0.48), mixed grasses and trees (0.42) to relatively natural vegetation (0.12). The established modular model, reflecting the driving hydrological processes, enables the quantification of land use specific contributions towards the baseflow and quickflow components. This quantification facilitates the integration of water sensitive urban infrastructure for the sustainable development of water in tropical megacities.

Remotely-Sensed Urban Wet-Landscapes AN Indicator of Coupled Effects of Human Impact and Climate Change

NASA Astrophysics Data System (ADS)

Ji, Wei

2016-06-01

This study proposes the concept of urban wet-landscapes (loosely-defined wetlands) as against dry-landscapes (mainly impervious surfaces). The study is to examine whether the dynamics of urban wet-landscapes is a sensitive indicator of the coupled effects of the two major driving forces of urban landscape change - human built-up impact and climate (precipitation) variation. Using a series of satellite images, the study was conducted in the Kansas City metropolitan area of the United States. A rule-based classification algorithm was developed to identify fine-scale, hidden wetlands that could not be appropriately detected based on their spectral differentiability by a traditional image classification. The spatial analyses of wetland changes were implemented at the scales of metropolitan, watershed, and sub-watershed as well as based on the size of surface water bodies in order to reveal urban wetland change trends in relation to the driving forces. The study identified that wet-landscape dynamics varied in trend and magnitude from the metropolitan, watersheds, to sub-watersheds. The study also found that increased precipitation in the region in the past decades swelled larger wetlands in particular while smaller wetlands decreased mainly due to human development activities. These findings suggest that wet-landscapes, as against the dry-landscapes, can be a more effective indicator of the coupled effects of human impact and climate change.

A roadmap to effective urban climate change adaptation

NASA Astrophysics Data System (ADS)

Setiadi, R.

2018-03-01

This paper outlines a roadmap to effective urban climate change adaptation built from our practical understanding of the evidence and effects of climate change and the preparation of climate change adaptation strategies and plans. This roadmap aims to drive research in achieving fruitful knowledge and solution-based achievable recommendations in adapting to climate change in urban areas with effective and systematic manner. This paper underscores the importance of the interplay between local government initiatives and a national government for effective adaptation to climate change and takes into account the policy process and politics. This paper argues that effective urban climate change adaptation has a contribution to build urban resilience and helps the achievement of national government goals and targets in climate change adaptation.

Black carbon emissions in gasoline exhaust and a reduction alternative with a gasoline particulate filter.

PubMed

Chan, Tak W; Meloche, Eric; Kubsh, Joseph; Brezny, Rasto

2014-05-20

Black carbon (BC) mass and solid particle number emissions were obtained from two pairs of gasoline direct injection (GDI) vehicles and port fuel injection (PFI) vehicles over the U.S. Federal Test Procedure 75 (FTP-75) and US06 Supplemental Federal Test Procedure (US06) drive cycles on gasoline and 10% by volume blended ethanol (E10). BC solid particles were emitted mostly during cold-start from all GDI and PFI vehicles. The reduction in ambient temperature had significant impacts on BC mass and solid particle number emissions, but larger impacts were observed on the PFI vehicles than the GDI vehicles. Over the FTP-75 phase 1 (cold-start) drive cycle, the BC mass emissions from the two GDI vehicles at 0 °F (-18 °C) varied from 57 to 143 mg/mi, which was higher than the emissions at 72 °F (22 °C; 12-29 mg/mi) by a factor of 5. For the two PFI vehicles, the BC mass emissions over the FTP-75 phase 1 drive cycle at 0 °F varied from 111 to 162 mg/mi, higher by a factor of 44-72 when compared to the BC emissions of 2-4 mg/mi at 72 °F. The use of a gasoline particulate filter (GPF) reduced BC emissions from the selected GDI vehicle by 73-88% at various ambient temperatures over the FTP-75 phase 1 drive cycle. The ambient temperature had less of an impact on particle emissions for a warmed-up engine. Over the US06 drive cycle, the GPF reduced BC mass emissions from the GDI vehicle by 59-80% at various temperatures. E10 had limited impact on BC emissions from the selected GDI and PFI vehicles during hot-starts. E10 was found to reduce BC emissions from the GDI vehicle by 15% at standard temperature and by 75% at 19 °F (-7 °C).

A novel high-temperature ejector-topping power cycle

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

Freedman, B.Z.; Lior, N.

1994-01-01

A novel, patented topping power cycle is described that takes its energy from a very high-temperature heat source and in which the temperature of the heat sink is still high enough to operate another, conventional power cycle. The top temperatures heat source is used to evaporate a low saturation pressure liquid, which serves as the driving fluid for compressing the secondary fluid in an ejector. Due to the inherently simple construction of ejectors, they are well suited for operation at temperatures higher than those that can be used with gas turbines. The gases exiting from the ejector transfer heat tomore » the lower temperature cycle, and are separated by condensing the primary fluid. The secondary gas is then used to drive a turbine. For a system using sodium as the primary fluid and helium as the secondary fluid, and using a bottoming Rankine steam cycle, the overall thermal efficiency can be at least 11 percent better than that of conventional steam Rankine cycles.« less

Real-world operation conditions and on-road emissions of Beijing diesel buses measured by using portable emission measurement system and electric low-pressure impactor.

PubMed

Liu, Zhihua; Ge, Yunshan; Johnson, Kent C; Shah, Asad Naeem; Tan, Jianwei; Wang, Chu; Yu, Linxiao

2011-03-15

On-road measurement is an effective method to investigate real-world emissions generated from vehicles and estimate the difference between engine certification cycles and real-world operating conditions. This study presents the results of on-road measurements collected from urban buses which propelled by diesel engine in Beijing city. Two widely used Euro III emission level buses and two Euro IV emission level buses were chosen to perform on-road emission measurements using portable emission measurement system (PEMS) for gaseous pollutant and Electric Low Pressure Impactor (ELPI) for particulate matter (PM) number emissions. The results indicate that considerable discrepancies of engine operating conditions between real-world driving cycles and engine certification cycles have been observed. Under real-world operating conditions, carbon monoxide (CO) and hydrocarbon (HC) emissions can easily meet their respective regulations limits, while brake specification nitrogen oxide (bsNO(x)) emissions present a significant deviation from its corresponding limit. Compared with standard limits, the real-world bsNO(x) emission of the two Euro III emission level buses approximately increased by 60% and 120% respectively, and bsNO(x) of two Euro IV buses nearly twice standard limits because Selective Catalytic Reduction (SCR) system not active under low exhaust temperature. Particle mass were estimated via particle size distribution with the assumption that particle density and diameter is liner. The results demonstrate that nanometer size particulate matter make significant contribution to total particle number but play a minor role to total particle mass. It is suggested that specific certified cycle should be developed to regulate bus engines emissions on the test bench or use PEMS to control the bus emissions under real-world operating conditions. Copyright © 2010 Elsevier B.V. All rights reserved.

Nitrate leaching and nitrous oxide flux in urban forests and grasslands

Treesearch

Peter M. Groffman; Candiss O. Williams; Richard V. Pouyat; Lawrence E. Band; Ian D. Yesilonis

2009-01-01

Urban landscapes contain a mix of land-use types with different patterns of nitrogen (N) cycling and export. We measured nitrate (NO3-) leaching and soil:atmosphere nitrous oxide (N2O) flux in four urban grassland and eight forested long-term study plots in the Baltimore, Maryland metropolitan area....

Coupling biogeochemical cycles in urban environments: Ecosystemservices, green solutions, and misconceptions

Treesearch

Diane Pataki; Margaret Carreiro; Jennifer Cherrier; Nancy Grulke; Viniece Jennings; Stephanie Pincetl; Richard Pouyat; Thomas Whitlow; Wayne Zipperer

2011-01-01

Urban green space is purported to offset greenhouse-gas (GHG) emissions, remove air and water pollutants, cool local climate, and improve public health. To use these services, municipalities have focused efforts on designing and implementing ecosystem-services-based "green infrastructure" in urban environments. In some cases the environmental benefits of this...

A Review of Quantitative Methods for Evaluating Impacts of Climate Change on Urban Water Infrastructure

EPA Science Inventory

It is widely accepted that global climate change will impact the regional and local climate and alter some aspects of the hydrologic cycle, which in turn can affect the performance of the urban water supply, wastewater and storm water infrastructur4e. How the urban water infrastr...

A decision support tool for sustainable planning of urban water systems: presenting the Dynamic Urban Water Simulation Model.

PubMed

Willuweit, Lars; O'Sullivan, John J

2013-12-15

Population growth, urbanisation and climate change represent significant pressures on urban water resources, requiring water managers to consider a wider array of management options that account for economic, social and environmental factors. The Dynamic Urban Water Simulation Model (DUWSiM) developed in this study links urban water balance concepts with the land use dynamics model MOLAND and the climate model LARS-WG, providing a platform for long term planning of urban water supply and water demand by analysing the effects of urbanisation scenarios and climatic changes on the urban water cycle. Based on potential urbanisation scenarios and their effects on a city's water cycle, DUWSiM provides the functionality for assessing the feasibility of centralised and decentralised water supply and water demand management options based on forecasted water demand, stormwater and wastewater generation, whole life cost and energy and potential for water recycling. DUWSiM has been tested using data from Dublin, the capital of Ireland, and it has been shown that the model is able to satisfactorily predict water demand and stormwater runoff. Copyright © 2013 Elsevier Ltd. All rights reserved.

Structural barriers to comprehensive, coordinated HIV care: geographic accessibility in the US South.

PubMed

Kimmel, April D; Masiano, Steven P; Bono, Rose S; Martin, Erika G; Belgrave, Faye Z; Adimora, Adaora A; Dahman, Bassam; Galadima, Hadiza; Sabik, Lindsay M

2018-05-30

Structural barriers to HIV care are particularly challenging in the US South, which has higher HIV diagnosis rates, poverty, uninsurance, HIV stigma, and rurality, and fewer comprehensive public health programs versus other US regions. Focusing on one structural barrier, we examined geographic accessibility to comprehensive, coordinated HIV care (HIVCCC) in the US South. We integrated publicly available data to study travel time to HIVCCC in 16 Southern states and District of Columbia. We geocoded HIVCCC service locations and estimated drive time between the population-weighted county centroid and closest HIVCCC facility. We evaluated drive time in aggregate, and by county-level HIV prevalence quintile, urbanicity, and race/ethnicity. Optimal drive time was ≤30 min, a common primary care accessibility threshold. We identified 228 service locations providing HIVCCC across 1422 Southern counties, with median drive time to care of 70 min (IQR 64 min). For 368 counties in the top HIV prevalence quintile, median drive time is 50 min (IQR 61 min), exceeding 60 min in over one-third of these counties. Among counties in the top HIV prevalence quintile, drive time to care is six-folder higher for rural versus super-urban counties. Counties in the top HIV prevalence quintiles for non-Hispanic Blacks and for Hispanics have >50% longer drive time to care versus for non-Hispanic Whites. Including another potential care source-publicly-funded health centers serving low-income populations-could double the number of high-HIV burden counties with drive time ≤30 min, representing nearly 35,000 additional people living with HIV with accessible HIVCCC. Geographic accessibility to HIVCCC is inadequate in the US South, even in high HIV burden areas, and geographic and racial/ethnic disparities exist. Structural factors, such as geographic accessibility to care, may drive disparities in health outcomes. Further research on programmatic policies, and evidence-based alternative HIV care delivery models improving access to care, is critical.

Plasma 17-alpha-OH-progesterone in female workers exposed to urban pollutants.

PubMed

Ciarrocca, M; Cerratti, D; Capozzella, A; Rosati, M V; Anzani, M F; Bernardini, A; Casale, T; Pimpinella, B; Tomei, G; Monti, C; Tomao, E; Tomei, F

2006-01-01

The aim of this study is to evaluate whether occupational exposure to urban pollutants could cause alteration in plasma 17-alpha-OH-P levels in female workers. After excluding the subjects with the principal confounding factors, traffic police and controls were matched by age, working life, age of menarche, menstrual cycle day, BMI, drinking habits, habitual consumption of soy and Italian coffee. 68 traffic police and 82 controls (7th day; follicular phase of the ovarian cycle), 37 traffic police and 20 controls (21st day; lutheal phase of the ovarian cycle) were included in the study and matched for the above mentioned variables. In follicular and lutheal phase of ovarian cycle, 17-alpha-OH-P mean levels and the distribution of 17-alpha-OH-P values were significantly higher in traffic police vs. controls. A higher instance of mental health disorders in traffic police vs. controls was found, although the difference was not significant. Considering that the potential confounding effect of extraneous factors was controlled by restricting the study population and by matching traffic police vs. controls on the above mentioned variables, our results suggest that occupational exposure to urban pollutants may alter plasma 17-alpha-OH-P concentrations. 17-alpha-OH-P could be used in an occupational setting as an early biomarker of exposure to urban pollutants, valuable for a group, even before the onset of related pathologies.

The role of population density on the impact of urbaniza-tion on GHG emissions in China

NASA Astrophysics Data System (ADS)

Liu, Yonghong; Gao, Chaochao; Lu, Yingying

2017-04-01

Urbanization directly drives rural to urban population migration and indirectly causes west to east migration in China, two phenomena that may significantly impact China's greenhouse gas emissions given its huge population and vast difference between the western rural and eastern urban areas. These two phenomena were analyzed by using emissions as a per capita term, and extending the impact from the traditional urbanization rate effect to include population density effect. The results show that population density has actually been the dominant demographic player in changing per capita emissions for the past two decades in China, and its elasticity changed from positive in economically less-developed provinces to negative for the developed provinces. This study provides a new perspective in the study of the relationship between urbanization and greenhouse gas emissions, and the results indicate that population density change should be taken into account to accurately assess the impact of urbanization.

Coordination of cell death and the cell cycle: linking proliferation to death through private and communal couplers.

PubMed

Abrams, John M; White, Michael A

2004-12-01

In development and in the adult, complex signaling pathways operate within and between cells to coordinate proliferation and cell death. These networks can be viewed as coupling devices that link engines driving the cell cycle and the initiation of apoptosis. We propose three simple frameworks for modeling the effects of proliferative drive on apoptotic propensity. This perspective offers a potentially useful foundation for predicting group behaviors of cells in normal and pathological settings.

Fuel and Emissions Reduction in Electric Power Take-Off Equipped Utility Vehicles

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

Konan, Arnaud; Ragatz, Adam; Prohaska, Robert

The National Renewable Energy Laboratory (NREL) evaluated the performance of Pacific Gas and Electric plug-in hybrid electric power take off (ePTO) utility trucks equipped with Altec, Inc.'s Jobsite Energy Management System. NREL collected on-road performance data from Class 5 utility 'trouble trucks' and Class 8 material handlers and developed representative drive cycles for chassis dynamometer testing. The drive cycles were analyzed and jobsite energy use was quantified for impacts and potential further hybridization for the utility truck vocation.

Response of vegetation phenology to urbanization in the conterminous United States

DOE PAGES

Li, Xuecao; Zhou, Yuyu; Asrar, Ghassem R.; ...

2016-12-18

The influence of urbanization on vegetation phenology is gaining considerable attention due to its implications for human health, cycling of carbon and other nutrients in Earth system. In this study, we examined the relationship between change in vegetation phenology and urban size, an indicator of urbanization, for the conterminous United States. We studied more than 4500 urban clusters of varying size to determine the impact of urbanization on plant phenology, with the aids of remotely sensed observations since 2003–2012. We found that phenology cycle (changes in vegetation greenness) in urban areas starts earlier (start of season, SOS) and ends latermore » (end of season, EOS), resulting in a longer growing season length (GSL), when compared to the respective surrounding urban areas. The average difference of GSL between urban and rural areas over all vegetation types, considered in this study, is about 9 days.Also, the extended GSL in urban area is consistent among different climate zones in the United States, whereas their magnitudes are varying across regions. We found that a tenfold increase in urban size could result in an earlier SOS of about 1.3 days and a later EOS of around 2.4 days. As a result, the GSL could be extended by approximately 3.6 days with a range of 1.6–6.5 days for 25th ~ 75th quantiles, with a median value of about 2.1 days. For different vegetation types, the phenology response to urbanization, as defined by GSL, ranges from 1 to 4 days. In conclusion, the quantitative relationship between phenology and urbanization is of great use for developing improved models of vegetation phenology dynamics under future urbanization, and for developing change indicators to assess the impacts of urbanization on vegetation phenology.« less

Volunteering, Driving Status and Mortality in US Retirees

PubMed Central

Lee, Sei J.; Steinman, Michael A.; Tan, Erwin J.

2011-01-01

OBJECTIVES: Volunteering is associated with lower mortality in the elderly. Driving is associated with health and well-being and driving cessation has been associated with decreased out-of-home activity levels including volunteering. We evaluated how accounting for driving status altered the relationship between volunteering and mortality in US retirees. DESIGN: Observational prospective cohort SETTING and PARTICIPANTS: Nationally representative sample of retirees over age 65 from the Health and Retirement Study in 2000 and 2002, followed to 2006 (n=6408). MEASUREMENTS: Participants self-reported their volunteering, driving status, age, gender and race/ethnicity, presence of chronic conditions, geriatrics syndromes, socioeconomic factors, functional limitations and psychosocial factors. Death by December 31, 2006 was the outcome. RESULTS: For drivers, the mortality rates between volunteers (9%) and non-volunteers (12%) were similar; for limited or non-drivers, the mortality rate for volunteers (15%) was markedly lower compared to non-volunteers (32%). Our adjusted results showed that for drivers, the volunteering-mortality Odds Ratio (OR) was 0.90 (95%CI: 0.66–1.22), whereas for limited or non-drivers, the OR was 0.62 (95%CI: 0.49–0.78), (interaction p=0.05). The impact of driving status was greater for rural participants, with greater differences between rural drivers versus rural limited or non-drivers (interaction p=0.02) compared to urban drivers versus urban limited or non-drivers (interaction p=0.81). CONCLUSION: The influence of volunteering in decreasing mortality seems to be stronger among rural retirees who are limited or non-drivers. This may be because rural or non-driving retirees are more likely to be socially isolated and thus receive more benefit from the increased social integration from volunteering. PMID:21314648

Common Traffic Violations of Bus Drivers in Urban China: An Observational Study.

PubMed

Wang, Qiqi; Zhang, Wei; Yang, Rendong; Huang, Yuanxiu; Zhang, Lin; Ning, Peishan; Cheng, Xunjie; Schwebel, David C; Hu, Guoqing; Yao, Hongyan

2015-01-01

To report common traffic violations in bus drivers and the factors that influence those violations in urban China. We conducted an observational study to record three types of traffic violations among bus drivers in Changsha City, China: illegal stopping at bus stations, violating traffic light signals, and distracted driving. The behaviors of bus drivers on 32 routes (20% of bus routes in the city) were observed. A two-level Poisson regression examined factors that predicted bus driver violations. The incidence of illegal stopping at bus stations was 20.2%. Illegal stopping was less frequent on weekends, sunny days, and at stations with cameras, with adjusted incidence rate ratios (IRRs) of 0.81, 0.65 and 0.89, respectively. The incidence of violating traffic light signals was 2.2%, and was lower on cloudy than sunny days (adjusted IRR: 0.60). The incidence of distracted driving was 3.3%. The incidence of distracted driving was less common on cloudy days, rainy or snowy days, and foggy/windy/dusty days compared to sunny days, with adjusted IRRs of 0.54, 0.55 and 0.07, respectively. Traffic violations are common in bus drivers in urban China and they are associated with the date, weather, and presence of traffic cameras at bus station. Further studies are recommended to understand the behavioral mechanisms that may explain bus driver violations and to develop feasible prevention measures.

The impact of texting on driver behaviour at rail level crossings.

PubMed

Young, Kristie L; Lenné, Michael G; Salmon, Paul M; Stanton, Neville A

2018-05-21

A driver text messaging in the vicinity of a rail level crossing represents the merging of a high-risk, high-workload driving environment with a highly distracting secondary task. In this simulator study, we examined how texting impacts driver behaviour on approach to actively controlled urban rail level crossings. Twenty-eight participants drove a series of simulated urban routes containing rail level crossings, while sending text messages and while driving without performing a secondary task. At half of the crossings, drivers were required to respond to the crossing warnings as a train approached. Results revealed that texting on approach to rail level crossings had a detrimental impact on a range of driver behaviour measures. Specifically, texting more than doubled the amount of time spent with eyes off the forward roadway, resulting in drivers spending more than half of their approach time to rail level crossings looking away from the road. This lack of visual attention to the roadway was associated with a range of decrements in driving that may be indicative of a loss of situation awareness, including increased brake reaction time to the crossing warnings and a reduction in lateral position control. The findings have safety implications, not only for urban level crossings, but also for passive level crossings where no warnings are present to re-orient the distracted driver's attention toward an approaching train. Copyright © 2018 Elsevier Ltd. All rights reserved.

Simulation of Automated Vehicles' Drive Cycles

DOT National Transportation Integrated Search

2018-02-28

This research has two objectives: 1) To develop algorithms for plausible and legally-justifiable freeway car-following and arterial-street gap acceptance driving behavior for AVs 2) To implement these algorithms on a representative road network, in o...

On-road heavy-duty diesel particulate matter emissions modeled using chassis dynamometer data.

PubMed

Kear, Tom; Niemeier, D A

2006-12-15

This study presents a model, derived from chassis dynamometer test data, for factors (operational correction factors, or OCFs) that correct (g/mi) heavy-duty diesel particle emission rates measured on standard test cycles for real-world conditions. Using a random effects mixed regression model with data from 531 tests of 34 heavy-duty vehicles from the Coordinating Research Council's E55/E59 research project, we specify a model with covariates that characterize high power transient driving, time spent idling, and average speed. Gram per mile particle emissions rates were negatively correlated with high power transient driving, average speed, and time idling. The new model is capable of predicting relative changes in g/mi on-road heavy-duty diesel particle emission rates for real-world driving conditions that are not reflected in the driving cycles used to test heavy-duty vehicles.

Mapping commuter cycling risk in urban areas.

PubMed

Yiannakoulias, Nikolaos; Bennet, Scott A; Scott, Darren M

2012-03-01

Cycling is becoming an increasingly important transportation option for commuters. Cycling offers exercise opportunities and reduces the burden of motor vehicle travel on society. Mapping the risk of collision between cyclists and motor vehicles in urban areas is important to understanding safe cyclist route opportunities, making informed transportation planning decisions, and exploring patterns of injury epidemiology. To date, many geographic analyses and representations of cyclist risk have not taken the concept of exposure into account. Instead, risk is either expressed as a rate per capita, or as a count of events. Using data associated with the City of Hamilton, Canada, we illustrate a method for mapping commuter cyclist collision risk per distance travelled. This measure can be used to more realistically represent the underlying geography of cycling risk, and provide more geographically and empirically meaningful information to those interested in understanding how cycling safety varies over space. Copyright © 2011 Elsevier Ltd. All rights reserved.

Urbanization breaks up host-parasite interactions: a case study on parasite community ecology of rufous-bellied thrushes (Turdus rufiventris) along a rural-urban gradient.

PubMed

Calegaro-Marques, Cláudia; Amato, Suzana B

2014-01-01

Urbanization drastically alters natural ecosystems and the structure of their plant and animal communities. Whereas some species cope successfully with these environmental changes, others may go extinct. In the case of parasite communities, the expansion of urban areas has a critical effect by changing the availability of suitable substrates for the eggs or free-larval stages of those species with direct life cycles or for the range of hosts of those species with complex cycles. In this study we investigated the influence of the degree of urbanization and environmental heterogeneity on helminth richness, abundance and community structure of rufous-bellied thrushes (Turdus rufiventris) along a rural-urban gradient in the metropolitan region of Porto Alegre, State of Rio Grande do Sul, Brazil. This common native bird species of southern Brazil hosts 15 endoparasite species at the study region. A total of 144 thrushes were collected with mist nets at 11 sites. The degree of urbanization and environmental heterogeneity were estimated by quantifying five landscape elements: buildings, woodlands, fields, bare lands, and water. Landscape analyses were performed at two spatial scales (10 and 100 ha) taking into account home range size and the potential dispersal distance of thrushes and their prey (intermediate hosts). Mean parasite richness showed an inverse relationship with the degree of urbanization, but a positive relationship with environmental heterogeneity. Changes in the structure of component communities along the rural-urban gradient resulted from responses to the availability of particular landscape elements that are compatible with the parasites' life cycles. We found that the replacement of natural environments with buildings breaks up host-parasite interactions, whereas a higher environmental (substrate) diversity allows the survival of a wider range of intermediate hosts and vectors and their associated parasites.

Effect of Drive Cycle and Gasoline Particulate Filter on the Size and Morphology of Soot Particles Emitted from a Gasoline-Direct-Injection Vehicle.

PubMed

Saffaripour, Meghdad; Chan, Tak W; Liu, Fengshan; Thomson, Kevin A; Smallwood, Gregory J; Kubsh, Joseph; Brezny, Rasto

2015-10-06

The size and morphology of particulate matter emitted from a light-duty gasoline-direct-injection (GDI) vehicle, over the FTP-75 and US06 transient drive cycles, have been characterized by transmission-electron-microscope (TEM) image analysis. To investigate the impact of gasoline particulate filters on particulate-matter emission, the results for the stock-GDI vehicle, that is, the vehicle in its original configuration, have been compared to the results for the same vehicle equipped with a catalyzed gasoline particulate filter (GPF). The stock-GDI vehicle emits graphitized fractal-like aggregates over all driving conditions. The mean projected area-equivalent diameter of these aggregates is in the 78.4-88.4 nm range and the mean diameter of primary particles varies between 24.6 and 26.6 nm. Post-GPF particles emitted over the US06 cycle appear to have an amorphous structure, and a large number of nucleation-mode particles, depicted as low-contrast ultrafine droplets, are observed in TEM images. This indicates the emission of a substantial amount of semivolatile material during the US06 cycle, most likely generated by the incomplete combustion of accumulated soot in the GPF during regeneration. The size of primary particles and soot aggregates does not vary significantly by implementing the GPF over the FTP-75 cycle; however, particles emitted by the GPF-equipped vehicle over the US06 cycle are about 20% larger than those emitted by the stock-GDI vehicle. This may be attributed to condensation of large amounts of organic material on soot aggregates. High-contrast spots, most likely solid nonvolatile cores, are observed within many of the nucleation-mode particles emitted over the US06 cycle by the GPF-equipped vehicle. These cores are either generated inside the engine or depict incipient soot particles which are partially carbonized in the exhaust line. The effect of drive cycle and the GPF on the fractal parameters of particles, such as fractal dimension and fractal prefactor, is insignificant.

What Is Driving the Observed Changes in Flooding in the Turkey River in Iowa?

NASA Astrophysics Data System (ADS)

Smith, C.; Yu, G.; Wright, D.

2017-12-01

Flooding can have severe societal, economic, and environmental consequences. In the United States-and worldwide-flooding causes fatalities and billions of dollars in economic loss. Recent research has pointed to changing flood risks in the Midwestern United States. However, we have a limited understanding of what natural and human factors are driving these changes. Researchers have proposed several possible explanations. Increasing intensity of short-duration summertime rainfall, reduced snow cover and earlier snow and soil thaw, changes in land surface evapotranspiration, and the effects of urbanization and agricultural management practices may all play roles in the shifts seen in the hydrologic cycle and flooding in Midwest. This study intends to look at the changes in the region on a smaller scale, whereas most previous research has examined at broad regional trends. Our focus will be on the agricultural Turkey River watershed in northeastern Iowa, where the flood hydroclimatology shows an abrupt shift around the year 1990 toward lower mean annual floods and dramatic increases in the magnitude and frequency of the largest floods. Analyses of land use, temperature, rainfall, river flow, and atmospheric properties, as well as simple continuous hydrologic simulations will aid in our understanding of the flood behavior of Turkey River and its drivers. In doing so, we hope to shed light on the causes of the changes in flooding and hydrology more generally that are taking place throughout the region.

Evaluation of the micro-carburetor

NASA Technical Reports Server (NTRS)

Weiss, M. F.; Hall, R. A.; Mazor, S. D.

1981-01-01

A prototype sonic, variable-venturi automotive carburetor was evaluated for its effects on vehicle performance, fuel economy, and exhaust emissions. A 350 CID Chevrolet Impala vehicle was tested on a chassis dynamometer over the 1975 Federal Test Procedure, urban driving cycle. The Micro-carburetor was tested and compared with stock and modified-stock engine configurations. Subsequently, the test vehicle's performance characteristics were examined with the stock carburetor and again with the Micro-carburetor in a series of on-road driveability tests. The test engine was then removed from the vehicle and installed on an engine dynamometer. Engine tests were conducted to compare the fuel economy, thermal efficiency, and cylinder-to-cylinder mixture distribution of the Micro-carburetor to that of the stock configuration. Test results show increases in thermal efficiency and improvements in fuel economy at all test conditions. Improve fuel/air mixture preparation is implied from the information presented. Further improvements in fuel economy and exhaust emissions are possible through a detailed recalibration of the Micro-carburetor.

Air flow and concentration fields at urban road intersections for improved understanding of personal exposure.

PubMed

Tiwary, Abhishek; Robins, Alan; Namdeo, Anil; Bell, Margaret

2011-07-01

This paper reviews the state of knowledge on modelling air flow and concentration fields at road intersections. The first part covers the available literature from the past two decades on experimental (both field and wind tunnel) and modelling activities in order to provide insight into the physical basis of flow behaviour at a typical cross-street intersection. This is followed by a review of associated investigations of the impact of traffic-generated localised turbulence on the concentration fields due to emissions from vehicles. There is a discussion on the role of adequate characterisation of vehicle-induced turbulence in making predictions using hybrid models, combining the merits of conventional approaches with information obtained from more detailed modelling. This concludes that, despite advancements in computational techniques, there are crucial knowledge gaps affecting the parameterisations used in current models for individual exposure. This is specifically relevant to the growing impetus on walking and cycling activities on urban roads in the context of current drives for sustainable transport and healthy living. Due to inherently longer travel times involved during such trips, compared to automotive transport, pedestrians and cyclists are subjected to higher levels of exposure to emissions. Current modelling tools seem to under-predict this exposure because of limitations in their design and in the empirical parameters employed. Copyright © 2011 Elsevier Ltd. All rights reserved.

A gradient analysis on urban sprawl and urban landscape pattern between 1985 and 2000 in the Pearl River Delta, China

NASA Astrophysics Data System (ADS)

Dai, Erfu; Wu, Zhuo; Du, Xiaodian

2017-04-01

Urbanization is an irreversible trend worldwide, especially in rapidly developing China. Accelerated urbanization has resulted in rapid urban sprawl and urban landscape pattern changes. Quantifying the spatiotemporal dynamics of urban land use and landscape pattern not only can reveal the characteristics of social transfer and economic development, but also can provide insights into the driving mechanisms of land use changes. In this study, we integrated remote sensing (RS), geographic information system (GIS), landscape metrics, and gradient analysis to quantitatively compare the spatiotemporal dynamics of land use, urban sprawl, and landscape pattern for nine cities in the Pearl River Delta from 1985‒2000. For the whole study region, urbanization was obvious. The results show an increase in urban buildup land and shrinkage of cropland in the Pearl River Delta. However, the nine cities differed greatly in terms of the process and magnitude of urban sprawl for both the spatial and temporal dimensions. This was most evident for the cities of Guangzhou and Shenzhen. Gradient analysis on urban landscape changes could deepen understanding of the stages of urban development and provide a scientific foundation for future urban planning and land management strategies in China.

RS- and GIS-based study on landscape pattern change in the Poyang Lake wetland area, China

NASA Astrophysics Data System (ADS)

Chen, Xiaoling; Li, Hui; Bao, Shuming; Wu, Zhongyi; Fu, Weijuan; Cai, Xiaobin; Zhao, Hongmei; Guo, Peng

2006-10-01

As wetland has been recognized as an important component of ecosystem, it is received ever-increasing attention worldwide. Poyang Lake wetlands, the international wetlands and the largest bird habitat in Asia, play an important role in biodiversity and ecologic protection. However, with the rapid economic growth and urbanization, landscape patterns in the wetlands have dramatically changed in the past three decades. To better understand the wetland landscape dynamics, remote sensing, geographic information system technologies, and the FRAGSTATS landscape analysis program were used to measure landscape patterns. Statistical approach was employed to illustrate the driving forces. In this study, Landsat images (TM and ETM+) from 1989 and 2000 were acquired for the wetland area. The landscapes in the wetland area were classified as agricultural land, urban, wetland, forest, grassland, unused land, and water body using a combination of supervised and unsupervised classification techniques integrated with Digital Elevation Model (DEM). Landscape indices, which are popular for the quantitative analysis of landscape pattern, were then employed to analyze the landscape pattern changes between the two dates in a GIS. From this analysis an understanding of the spatial-temporal patterns of landscape evolution was generated. The results show that wetland area was reduced while fragmentation was increased over the study period. Further investigation was made to examine the relationship between landscape metrics and some other parameters such as urbanization to address the driving forces for those changes. The urban was chosen as center to conduct buffer analysis in a GIS to study the impact of human-induced activities on landscape pattern dynamics. It was found that the selected parameters were significantly correlated with the landscape metrics, which may well indicate the impact of human-induced activities on the wetland landscape pattern dynamics and account for the driving forces.

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

Li, Xuecao; Zhou, Yuyu; Asrar, Ghassem R.

The influence of urbanization on vegetation phenology is gaining considerable attention due to its implications for human health, cycling of carbon and other nutrients in Earth system. In this study, we examined the relationship between change in vegetation phenology and urban size, an indicator of urbanization, for the conterminous United States. We studied more than 4500 urban clusters of varying size to determine the impact of urbanization on plant phenology, with the aids of remotely sensed observations since 2003–2012. We found that phenology cycle (changes in vegetation greenness) in urban areas starts earlier (start of season, SOS) and ends latermore » (end of season, EOS), resulting in a longer growing season length (GSL), when compared to the respective surrounding urban areas. The average difference of GSL between urban and rural areas over all vegetation types, considered in this study, is about 9 days.Also, the extended GSL in urban area is consistent among different climate zones in the United States, whereas their magnitudes are varying across regions. We found that a tenfold increase in urban size could result in an earlier SOS of about 1.3 days and a later EOS of around 2.4 days. As a result, the GSL could be extended by approximately 3.6 days with a range of 1.6–6.5 days for 25th ~ 75th quantiles, with a median value of about 2.1 days. For different vegetation types, the phenology response to urbanization, as defined by GSL, ranges from 1 to 4 days. In conclusion, the quantitative relationship between phenology and urbanization is of great use for developing improved models of vegetation phenology dynamics under future urbanization, and for developing change indicators to assess the impacts of urbanization on vegetation phenology.« less

Safety in numbers? Investigating Australian driver behaviour, knowledge and attitudes towards cyclists.

PubMed

Johnson, Marilyn; Oxley, Jennie; Newstead, Stuart; Charlton, Judith

2014-09-01

A key tenet of the safety in numbers theory is that as the number of people cycling increases, more drivers will also be cyclists and therefore will give greater consideration to cyclists when driving. We tested this theory in relation to self-reported behaviour, attitudes and knowledge in relation to cycling. An online survey was conducted of Australian drivers (n=1984) who were also cyclists (cyclist-drivers) and drivers who did not cycle (drivers). Cyclist-drivers were 1.5 times more likely than drivers to report safe driving behaviours related to sharing the roads with cyclists (95% CI: 1.1-1.9, p<0.01). Cyclist-drivers had better knowledge of the road rules related to cycling infrastructure than drivers; however knowledge of road rules related to bike lanes was low for both groups. Drivers were more likely than cyclist-drivers to have negative attitudes (e.g. cyclists are unpredictable and repeatedly overtaking cyclists is frustrating). Findings from this study highlight the need for increased education and awareness in relation to safe driving behaviour, road rules and attitudes towards cyclists. Specific recommendations are made for approaches to improve safety for cyclists. Copyright © 2014. Published by Elsevier Ltd.

Carbon Corrosion in PEM Fuel Cells and the Development of Accelerated Stress Tests

DOE PAGES

Macauley, Natalia; Papadias, Dennis D.; Fairweather, Joseph; ...

2018-03-15

Here, carbon corrosion is an important degradation mechanism that can impair PEMFC performance through the destruction of catalyst connectivity, collapse of the electrode pore structure, loss of hydrophobic character, and an increase of the catalyst particle size. In this study, carbon corrosion was quantified in situ by measurement of carbon dioxide in the fuel cell exhaust gases through non-dispersive infrared spectroscopy during simulated drive cycle operations consisting of potential cycling with varying upper and lower potential limits. These studies were conducted for three different types of carbon supports. A reduction in the catalyst layer thickness was observed during a simulatedmore » drive cycle operation with a concomitant decrease in catalyst layer porosity, which led to performance losses due to increased mass transport limitations. The observed thickness reduction was primarily due to compaction of the catalyst layer, with the actual mass of carbon oxidation (loss) contributing only a small fraction (< 20%). The dynamics of carbon corrosion are presented along with a model that simulates the transient and dynamic corrosion rates observed in our experiments. Accelerated carbon corrosion stress tests are presented and their effects are compared to those observed for the drive cycle test.« less

Carbon Corrosion in PEM Fuel Cells and the Development of Accelerated Stress Tests

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

Macauley, Natalia; Papadias, Dennis D.; Fairweather, Joseph

Here, carbon corrosion is an important degradation mechanism that can impair PEMFC performance through the destruction of catalyst connectivity, collapse of the electrode pore structure, loss of hydrophobic character, and an increase of the catalyst particle size. In this study, carbon corrosion was quantified in situ by measurement of carbon dioxide in the fuel cell exhaust gases through non-dispersive infrared spectroscopy during simulated drive cycle operations consisting of potential cycling with varying upper and lower potential limits. These studies were conducted for three different types of carbon supports. A reduction in the catalyst layer thickness was observed during a simulatedmore » drive cycle operation with a concomitant decrease in catalyst layer porosity, which led to performance losses due to increased mass transport limitations. The observed thickness reduction was primarily due to compaction of the catalyst layer, with the actual mass of carbon oxidation (loss) contributing only a small fraction (< 20%). The dynamics of carbon corrosion are presented along with a model that simulates the transient and dynamic corrosion rates observed in our experiments. Accelerated carbon corrosion stress tests are presented and their effects are compared to those observed for the drive cycle test.« less

Emission rates of regulated pollutants from current technology heavy-duty diesel and natural gas goods movement vehicles.

PubMed

Thiruvengadam, Arvind; Besch, Marc C; Thiruvengadam, Pragalath; Pradhan, Saroj; Carder, Daniel; Kappanna, Hemanth; Gautam, Mridul; Oshinuga, Adewale; Hogo, Henry; Miyasato, Matt

2015-04-21

Chassis dynamometer emissions testing of 11 heavy-duty goods movement vehicles, including diesel, natural gas, and dual-fuel technology, compliant with US-EPA 2010 emissions standard were conducted. Results of the study show that three-way catalyst (TWC) equipped stoichiometric natural gas vehicles emit 96% lower NOx emissions as compared to selective catalytic reduction (SCR) equipped diesel vehicles. Characteristics of drayage truck vocation, represented by the near-dock and local drayage driving cycles, were linked to high NOx emissions from diesel vehicles equipped with a SCR. Exhaust gas temperatures below 250 °C, for more than 95% duration of the local and near-dock driving cycles, resulted in minimal SCR activity. The low percentage of activity SCR over the local and near-dock cycles contributed to a brake-specific NOx emissions that were 5-7 times higher than in-use certification limit. The study also illustrated the differences between emissions rate measured from chassis dynamometer testing and prediction from the EMFAC model. The results of the study emphasize the need for model inputs relative to SCR performance as a function of driving cycle and engine operation characteristics.

High resolution remote sensing for reducing uncertainties in urban forest carbon offset life cycle assessments.

PubMed

Tigges, Jan; Lakes, Tobia

2017-10-04

Urban forests reduce greenhouse gas emissions by storing and sequestering considerable amounts of carbon. However, few studies have considered the local scale of urban forests to effectively evaluate their potential long-term carbon offset. The lack of precise, consistent and up-to-date forest details is challenging for long-term prognoses. Therefore, this review aims to identify uncertainties in urban forest carbon offset assessment and discuss the extent to which such uncertainties can be reduced by recent progress in high resolution remote sensing. We do this by performing an extensive literature review and a case study combining remote sensing and life cycle assessment of urban forest carbon offset in Berlin, Germany. Recent progress in high resolution remote sensing and methods is adequate for delivering more precise details on the urban tree canopy, individual tree metrics, species, and age structures compared to conventional land use/cover class approaches. These area-wide consistent details can update life cycle inventories for more precise future prognoses. Additional improvements in classification accuracy can be achieved by a higher number of features derived from remote sensing data of increasing resolution, but first studies on this subject indicated that a smart selection of features already provides sufficient data that avoids redundancies and enables more efficient data processing. Our case study from Berlin could use remotely sensed individual tree species as consistent inventory of a life cycle assessment. However, a lack of growth, mortality and planting data forced us to make assumptions, therefore creating uncertainty in the long-term prognoses. Regarding temporal changes and reliable long-term estimates, more attention is required to detect changes of gradual growth, pruning and abrupt changes in tree planting and mortality. As such, precise long-term urban ecological monitoring using high resolution remote sensing should be intensified, especially due to increasing climate change effects. This is important for calibrating and validating recent prognoses of urban forest carbon offset, which have so far scarcely addressed longer timeframes. Additionally, higher resolution remote sensing of urban forest carbon estimates can improve upscaling approaches, which should be extended to reach a more precise global estimate for the first time. Urban forest carbon offset can be made more relevant by making more standardized assessments available for science and professional practitioners, and the increasing availability of high resolution remote sensing data and the progress in data processing allows for precisely that.

The risk of urban yellow fever resurgence in Aedes-infested American cities.

PubMed

Massad, Eduardo; Amaku, Marcos; Coutinho, Francisco Antonio Bezerra; Struchiner, Claudio José; Lopez, Luis Fernandez; Coelho, Giovanini; Wilder-Smith, Annelies; Burattini, Marcelo Nascimento

2018-05-30

Aedes aegypti, historically known as yellow fever (YF) mosquito, transmits a great number of other viruses such as Dengue, West Nile, Chikungunya, Zika, Mayaro and perhaps Oropouche, among others. Well established in Africa and Asia, Aedes mosquitoes are now increasingly invading large parts of the American continent, and hence the risk of urban YF resurgence in the American cities should because of great concern to public health authorities. Although no new urban cycle of YF was reported in the Americas since the end of an Aedes eradication programme in the late 1950s, the high number of non-vaccinated individuals that visit endemic areas, that is, South American jungles where the sylvatic cycle of YF is transmitted by canopy mosquitoes, and return to Aedes-infested urban areas, increases the risk of resurgence of the urban cycle of YF. We present a method to estimate the risk of urban YF resurgence in dengue-endemic cities. This method consists in (1) to estimate the number of Aedes mosquitoes that explains a given dengue outbreak in a given region; (2) calculate the force of infection caused by the introduction of one infective individual per unit area in the endemic area under study; (3) using the above estimates, calculate the probability of at least one autochthonous YF case per unit area produced by one single viraemic traveller per unit area arriving from a YF endemic or epidemic sylvatic region at the city studied. We demonstrate that, provided the relative vector competence, here defined as the capacity to being infected and disseminate the virus, of Ae. aegypti is greater than 0.7 (with respect to dengue), one infected traveller can introduce urban YF in a dengue endemic area.

Turnover at the Top: Superintendent Vacancies and the Urban School

ERIC Educational Resources Information Center

Buchanan, Bruce

2006-01-01

The leadership turnover in America's largest school districts has increased so rapidly that the average urban superintendent tenure is only about two years. In fact, many urban superintendents are hired knowing that they will either be terminated or forced to resign in a short period of time. This cycle has created a class of superintendents who…

Foliar nitrogen characteristics of four tree species planted in New York City forest restoration sites

Treesearch

Nancy Falxa-Raymond; Matthew I. Palmer; Timon McPhearson; Kevin L. Griffin

2014-01-01

Urban forests provide important environmental benefits, leading many municipal governments to initiate citywide tree plantings. However, nutrient cycling in urban ecosystems is difficult to predict, and nitrogen (N) use in urban trees may be quite different from use in rural forests. To gain insight into these biogeochemical and physiological processes, we compared...

Climate variability drives population cycling and synchrony

Treesearch

Lars Y. Pomara; Benjamin Zuckerberg

2017-01-01

Aim There is mounting concern that climate change will lead to the collapse of cyclic population dynamics, yet the influence of climate variability on population cycling remains poorly understood. We hypothesized that variability in survival and fecundity, driven by climate variability at different points in the life cycle, scales up from...

Analyzing Vehicle Fuel Saving Opportunities through Intelligent Driver Feedback

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

Gonder, J.; Earleywine, M.; Sparks, W.

2012-06-01

Driving style changes, e.g., improving driver efficiency and motivating driver behavior changes, could deliver significant petroleum savings. This project examines eliminating stop-and-go driving and unnecessary idling, and also adjusting acceleration rates and cruising speeds to ideal levels to quantify fuel savings. Such extreme adjustments can result in dramatic fuel savings of over 30%, but would in reality only be achievable through automated control of vehicles and traffic flow. In real-world driving, efficient driving behaviors could reduce fuel use by 20% on aggressively driven cycles and by 5-10% on more moderately driven trips. A literature survey was conducted of driver behaviormore » influences, and pertinent factors from on-road experiments with different driving styles were observed. This effort highlighted important driver influences such as surrounding vehicle behavior, anxiety over trying to get somewhere quickly, and the power/torque available from the vehicle. Existing feedback approaches often deliver efficiency information and instruction. Three recommendations for maximizing fuel savings from potential drive cycle improvement are: (1) leveraging applications with enhanced incentives, (2) using an approach that is easy and widely deployable to motivate drivers, and (3) utilizing connected vehicle and automation technologies to achieve large and widespread efficiency improvements.« less

Real-time black carbon emission factors of light-duty vehicles tested on a chassis dynamometer

NASA Astrophysics Data System (ADS)

Forestieri, S. D.; Cappa, C. D.; Kuwayama, T.; Collier, S.; Zhang, Q.; Kleeman, M. J.

2012-12-01

Eight light-duty gasoline vehicles were tested on a Chassis dynamometer using the California Unified Driving Cycle (UDC) at the Haagen-Smit vehicle test facility at the California Air Resources Board (CARB) in El Monte, CA during September 2011. In addition, one light-duty gasoline vehicle, one ultra low-emission vehicle, one diesel passenger vehicle, and one gasoline direct injection vehicle were tested on a constant velocity driving cycle. Vehicle exhaust was diluted through CARB's CVS tunnel and a secondary dilution system in order to examine particulate matter (PM) emissions at atmospherically relevant concentrations (5-30 μg-m3). A variety of real-time instrumentation was used to characterize how the major PM components vary during a typical driving cycle, which includes a cold start phase followed by a hot stabilized running phase. Aerosol absorption coefficients were obtained at 532 nm and 405 nm with a time resolution of 2 seconds from a photo-acoustic spectrometer. These absorption coefficients were then converted to black carbon (BC) concentrations via a mass absorption coefficient. Non-refractory organic and inorganic PM and CO2 concentrations were quantified with a time resolution of 10 seconds using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). Real-time BC and CO2 concentrations allowed for the determination of BC emission factors (EFs), providing insights into the variability of BC EFs during different phases of a typical driving cycle and aiding in the modeling BC emissions.

EVALUATION OF RANGE ESTIMATES FOR TOYOTA FCHV-ADV UNDER OPEN ROAD DRIVING CONDITIONS

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

Anton, D.; Wipke, K.; Sprik, S.

2009-07-10

The objective of this evaluation was to independently and objectively verify driving ranges of >400 miles announced by Toyota for its new advanced Fuel Cell Hybrid Vehicle (FCHV-adv) utilizing 70 MPa compressed hydrogen. To accomplish this, participants from both Savannah River National Laboratory (SRNL) and the National Renewable Energy Laboratory (NREL) witnessed and participated in a 2-vehicle evaluation with Toyota Motor Engineering & Manufacturing North America, Inc. (TEMA) over a typical open road route for over 11 hours in one day with all relevant data recorded. SRNL and TEMA first entered into discussions of verifying the range of the advancedmore » Toyota Fuel Cell Hybrid Vehicle (FCHV-adv) in August 2008 resulting from reported 400+ mile range by Toyota. After extended negotiations, a CRADA agreement, SRNS CRADA No. CR-04-003, was signed on May 6, 2009. Subsequently, on June 30, 2009 SRNL and NREL participated in an all-day evaluation of the FCHV-adv with TEMA to determine the real-world driving range of this vehicle through on-road driving on an extended round-trip drive between Torrance and San Diego, California. SRNL and NREL observed the vehicles being refueled at Toyota's headquarters the day before the evaluation in Torrance, CA on June 29. At 8:00 AM on June 30, the vehicles departed Torrance north toward downtown Los Angeles, then west to the Pacific Coast Highway, and down to San Diego. After lunch the vehicles retraced their route back to Torrance. The traffic encountered was much heavier than anticipated, causing the vehicles to not return to Torrance until 9 PM. Each vehicle was driven by the same Toyota driver all day, with one SRNL/NREL observer in each vehicle the entire route. Data was logged by Toyota and analyzed by NREL. The maximum range of the FCHV-adv vehicles was calculated to be 431 miles under these driving conditions. This distance was calculated from the actual range of 331.5 miles during over 11 hours driving, plus 99.5 miles of additional range calculated from the average fuel economy from the day times the remaining usable hydrogen. Driving range results were independently calculated for each vehicle, and these results averaged together to achieve the final 431-mile range estimate. The uncertainty on these results is relatively low due to eight independent measurements of distance and six separate measurements of hydrogen usage, with a resulting uncertainty of {+-} 7 miles ({+-} 1.7%) based on spread between the low and high values from all of the multiple measurements. The average fuel economy resulting from the day's driving was 68.3 miles/kg and the total hydrogen stored on-board at 70 MPa was calculated to be 6.31 kg. The speed profiles were analyzed and compared to standard driving cycles, and were determined to be of moderate aggressiveness. The city segments of the route had average speeds slightly greater than the UDDS cycle and the highway segments were close to the HWFET & US06 cycles. The average acceleration for the highway driving was very close to the HWFET cycle, and the city portions had average accelerations lower than the UDDS and US06 cycles. We feel that the route accurately reflects realistic driving behaviors in southern California on a typical weekday, and is an appropriate benchmark to use in the verification of a fuel cell vehicle's range.« less

Climate Change and Examples of Combined HyspIRI VSWIR/TIR Advanced Level Products for Urban Ecosystems Analysis

NASA Technical Reports Server (NTRS)

Quattrochi, Dale A.

2010-01-01

It is estimated that 60-80% of the world population will live in urban environments by the end of this century. This growth of the urban population will effect the climate. This slide presentation examines the use of combined HyspIRI Visible ShortWave Infrared (VSWIR)/Thermal Infrared (TIR) to observe, monitor, measure and model many of the components that comprise urban ecosystems cycles.

Orbit transfer vehicle advanced expander cycle engine point design study. Volume 2: Study results

NASA Technical Reports Server (NTRS)

Diem, H. G.

1980-01-01

The design characteristics of the baseline engine configuration of the advanced expander cycle engine are described. Several aspects of engine optimization are considered which directly impact the design of the baseline thrust chamber. Four major areas of the power cycle optimization are emphasized: main turbine arrangement; cycle engine source; high pressure pump design; and boost pump drive.

Natural disasters and climate change call for the urgent decentralization of urban water systems.

PubMed

Vázquez-Rowe, Ian; Kahhat, Ramzy; Lorenzo-Toja, Yago

2017-12-15

Lima is gradually upgrading its urban water cycle to comply with improved sanitation standards, with the aim of treating the entire flow of water and wastewater that it creates. However, this paper examines the basic characteristics of the main treatment systems that are currently in operation in the Peruvian capital, highlighting the myopic and inefficient nature of these investments. It digs deep in the debate between centralized and decentralized water management systems in a city that is exposed to numerous hydro-meteorological and geological hazards. Previous errors that have occurred in the developed world throughout the evolution process of the urban water cycle should be taken into consideration prior to any infrastructure development in emerging countries. For the particular case of Lima, special emphasis should be given to the resilience of its urban water system in order to guarantee rapid recovery after disaster events. Copyright © 2017 Elsevier B.V. All rights reserved.

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

Nyhan, Marguerite; Sobolevsky, Stanislav; Kang, Chaogui

Air pollution related to traffic emissions pose an especially significant problem in cities; this is due to its adverse impact on human health and well-being. Previous studies which have aimed to quantify emissions from the transportation sector have been limited by either simulated or coarsely resolved traffic volume data. Emissions inventories form the basis of urban pollution models, therefore in this study, Global Positioning System (GPS) trajectory data from a taxi fleet of over 15,000 vehicles were analyzed with the aim of predicting air pollution emissions for Singapore. This novel approach enabled the quantification of instantaneous drive cycle parameters inmore » high spatio-temporal resolution, which provided the basis for a microscopic emissions model. Carbon dioxide (CO2), nitrogen oxides (NOx), volatile organic compounds (VOCs) and particulate matter (PM) emissions were thus estimated. Highly localized areas of elevated emissions levels were identified, with a spatio-temporal precision not possible with previously used methods for estimating emissions. Relatively higher emissions areas were mainly concentrated in a few districts that were the Singapore Downtown Core area, to the north of the central urban region and to the east of it. Daily emissions quantified for the total motor vehicle population of Singapore were found to be comparable to another emissions dataset Results demonstrated that high resolution spatio-temporal vehicle traces detected using GPS in large taxi fleets could be used to infer highly localized areas of elevated acceleration and air pollution emissions in cities, and may become a complement to traditional emission estimates, especially in emerging cities and countries where reliable fine-grained urban air quality data is not easily available. This is the first study of its kind to investigate measured microscopic vehicle movement in tandem with microscopic emissions modeling for a substantial study domain.« less

Characterizing land subsidence mechanisms as a function of urban basin geohazards using space geodesy

NASA Astrophysics Data System (ADS)

Bawden, G. W.

2016-12-01

Land subsidence in urban basins will likely become a more significant geohazard in many of the global sedimentary basins as population growth, resource availability, and climate change compound natural and anthropogenic contributors that influence basin elevation. Coastal basins are at the greatest risk where land subsidence is additive to sea level rise, thereby increasing the rate of exposure to coastal populations. Land surface elevation change is a function of many different parameters, including: elastic and inelastic surface response to managed and natural groundwater levels; anthropogenic activities (hydrocarbon extraction, wastewater injection, fracking, geothermal production, and mass redistribution); local tectonic deformation and regional tectonic drivers (such as repeated uplift and subsidence cycles above subduction zones); climate change (influencing the timing, magnitude, nature and duration of seasonal/annual precipitation and permafrost extent); material properties of the basin sediments (influencing susceptibility to soil compaction, oxidization, and dissolution); post glacial rebound; isostatic flexure associated with sea-level and local mass changes; and large scale gravitational processes (such as growth faults and landslides). Geodetic measurements, such as InSAR and GPS, help track spatial and temporal changes in both relative and absolute basin elevation thereby helping to characterize the mechanism(s) driving the geohazards. In addition to a number of commercial radar satellites, European Space Agency's Sentinel-1a/b satellites are beginning to provide a wealth of data over many basin targets with C-band (5.5 cm wavelength). The NISAR (NASA-ISRO Synthetic Aperture Radar) L-band (24 cm wavelength) mission (anticipated 2021 launch) will image nearly every basin globally every 12 days and data from the mission will help characterize land subsidence and many other solid-Earth and hydrologic geohazards that impact urban basins.

What Keeps Teachers in and What Drives Them out: How Urban Public, Urban Catholic, and Jewish Day Schools Affect Beginning Teachers' Careers

ERIC Educational Resources Information Center

Tamir, Eran

2013-01-01

Background: Teacher quality plays a key role in student learning outcomes. Yet, data suggest that elite college graduates who enter teaching are less likely to stay in schools serving low income and minority students compared to other teachers. Thus, many educators and policy makers agree that in order to equalize the playing field, recruitment,…

Urban change analysis and future growth of Istanbul.

PubMed

Akın, Anıl; Sunar, Filiz; Berberoğlu, Süha

2015-08-01

This study is aimed at analyzing urban change within Istanbul and assessing the city's future growth potential using appropriate approach modeling for the year 2040. Urban growth is a major driving force of land-use change, and spatial and temporal components of urbanization can be identified through accurate spatial modeling. In this context, widely used urban modeling approaches, such as the Markov chain and logistic regression based on cellular automata (CA), were used to simulate urban growth within Istanbul. The distance from each pixel to the urban and road classes, elevation, and slope, together with municipality and land use maps (as an excluded layer), were identified as factors. Calibration data were obtained from remotely sensed data recorded in 1972, 1986, and 2013. Validation was performed by overlaying the simulated and actual 2013 urban maps, and a kappa index of agreement was derived. The results indicate that urban expansion will influence mainly forest areas during the time period of 2013-2040. The urban expansion was predicted as 429 and 327 km(2) with the Markov chain and logistic regression models, respectively.

Seasonality of the urban heat island effect: patterns and drivers

NASA Astrophysics Data System (ADS)

Schatz, J.; Kucharik, C. J.

2014-12-01

We conducted a rigorous analysis of the drivers of seasonality in the urban heat island (UHI) effect. Many studies report annual cycles in UHI intensity and have attributed those patterns to various hypotheses, including seasonal trends in wind and clouds, prevalence of anti-cyclonic conditions, soil moisture, and day length. But to our knowledge, those hypotheses have never been tested, leaving a substantial gap in our basic understanding of the urban climate. We tested these and other hypotheses using two years of continuous temperature measurements from an array of 150 sensors in and around Madison, Wisconsin USA, an urban area of 407,000 surrounded by lakes and a rural landscape of agriculture, forests, wetlands, and grasslands. This is one of the best replicated urban climate arrays ever deployed, which allowed us to characterize the UHI in rich spatial and temporal detail and rigorously assess the biophysical and synoptic drivers of its seasonal variation. UHI intensities were typically highest in summer and lowest in winter. Seasonal trends in wind speed and cloud cover generally tracked annual trends in UHI intensity, with the clearer, calmer conditions conducive to stronger UHIs more common in summer. This is consistent with the hypothesis that seasonal trends in wind, clouds, and anti-cyclonic conditions drive UHI seasonality. However, clear, calm summer nights still had higher UHI intensities than clear, calm winter nights, indicating that some background factor shifted baseline UHI intensities throughout the year. We found that regional vegetation and snow cover conditions set distinct seasonal baselines for UHI intensity, with nighttime intensities averaging 4°C in summer and 1°C in winter. Synoptic and biophysical factors that vary on shorter time scales (e.g. wind, clouds, soil moisture, relative humidity) modified daily UHI intensity around those baselines by 1-3°C but were not the primary drivers of UHI seasonality, contrary to the most common hypotheses in the literature. In addition to clarifying the drivers of UHI seasonality, our results have implications for the design and interpretation of UHI studies, particularly in how the timing of data collection might affect results and conclusions.

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

Li, Xuecao; Zhou, Yuyu; Asrar, Ghassem R.

The influence of urbanization on vegetation phenology is gaining considerable attention due to its implications for human health, cycling of carbon and other nutrients in Earth system. In this study, we examined the relationship between change in vegetation phenology and urban size, an indicator of urbanization, for the conterminous United States. We studied more than 4500 urban clusters of varying size to determine the impact of urbanization on plant phenology, with the aids of remotely sensed observations since 2003–2012. We found that phenology cycle (changes in vegetation greenness) in rural areas starts earlier (start of season, SOS) and ends latermore » (end of season, EOS), resulting in a longer growing season length (GSL), when compared to the respective surrounding urban areas. The average difference of GSL between urban and rural areas over all vegetation types, considered in this study, is about 9 days. Also, the extended GSL in urban area is consistent among different climate zones in the United States, whereas their magnitudes are varying across regions. We found that a tenfold increase in urban size could result in an earlier SOS of about 1.3 days and a later EOS of around 2.4 days. As a result, the GSL could be extended by approximately 3.6 days with a range of 1.6–6.5 days for 25th ~ 75th quantiles, with a median value of about 2.1 days. For different vegetation types, the phenology response to urbanization, as defined by GSL, ranges from 1 to 4 days. The quantitative relationship between phenology and urbanization is of great use for developing improved models of vegetation phenology dynamics under future urbanization, and for developing change indicators to assess the impacts of urbanization on vegetation phenology.« less

Patterns, structures and regulations of domestic water cycle systems in China

NASA Astrophysics Data System (ADS)

Chu, Junying; Wang, Hao; Wang, Jianhua; Qin, Dayong

2010-05-01

Domestic water cycle systems serving as one critical component of artificial water cycle at the catchment's scale, is so closely related to public healthy, human rights and social-economic development, and has gained the highest priority in strategic water resource and municipal infrastructure planning. In this paper, three basic patterns of domestic water cycle systems are identified and analyzed, including rural domestic water system (i.e. primary level), urban domestic water system (i.e. intermediate level) and metropolitan domestic water system (i.e. senior level), with different "abstract-transport-consume-discharge" mechanisms and micro-components of water consumption (such as drinking, cooking, toilet flushing, showering or cleaning). The rural domestic water system is general simple with three basic "abstract-consume-discharge" mechanisms and micro-components of basic water consumption such as drinking, cooking, washing and sanitation. The urban domestic water system has relative complex mechanisms of "abstract-supply-consume-treatment-discharge" and more micro-components of water consumption such as bath, dishwashing or car washing. The metropolitan domestic water system (i.e. senior level) has the most complex mechanisms by considering internal water reuse, external wastewater reclamation, and nutrient recycling processes. The detailed structures for different water cycle pattern are presented from the aspects of water quantity, wastewater quality and nutrients flow. With the speed up of urbanization and development of social-economy in China, those three basic patterns are interacting, transforming and upgrading. According to the past experiences and current situations, urban domestic water system (i.e. intermediate level) is the dominant pattern based on indicator of system number or system scale. The metropolitan domestic water system (i.e. senior level) is the idealized model for the future development and management. Current domestic water system management efforts typically fail in China, because the approach is generally narrowly-focused and fragmented. This paper put forward a total-process control framework following the water and pollutants (or nutrients) flows along the dualistic domestic water cycle process. Five key objectives of domestic water cycle system regulation are identified including water use safety, water use equity, water saving, wastewater reduction and nutrient recycling. Comprehensive regulatory framework regarding administrative, economic, technical and social measures is recommended to promote sustainable domestic water usage and demand management. Considering the relatively low affordability in rural area, economic measures should be mainly applied in urban domestic water systems and metropolitan domestic water systems. Engineering or technological measures which are suitable to the three domestic water cycle systems are discussed respectively.

Effects of fresh lubricant oils on particle emissions emitted by a modern gasoline direct injection passenger car.

PubMed

Pirjola, Liisa; Karjalainen, Panu; Heikkilä, Juha; Saari, Sampo; Tzamkiozis, Theodoros; Ntziachristos, Leonidas; Kulmala, Kari; Keskinen, Jorma; Rönkkö, Topi

2015-03-17

Particle emissions from a modern turbocharged gasoline direct injection passenger car equipped with a three-way catalyst and an exhaust gas recirculation system were studied while the vehicle was running on low-sulfur gasoline and, consecutively, with five different lubrication oils. Exhaust particle number concentration, size distribution, and volatility were determined both at laboratory and on-road conditions. The results indicated that the choice of lubricant affected particle emissions both during the cold start and warm driving cycles. However, the contribution of engine oil depended on driving conditions being higher during acceleration and steady state driving than during deceleration. The highest emission factors were found with two oils that had the highest metal content. The results indicate that a 10% decrease in the Zn content of engine oils is linked with an 11-13% decrease to the nonvolatile particle number emissions in steady driving conditions and a 5% decrease over the New European Driving Cycle. The effect of lubricant on volatile particles was even higher, on the order of 20%.

Compilation of load spectrum of loader drive axle

NASA Astrophysics Data System (ADS)

Wei, Yongxiang; Zhu, Haoyue; Tang, Heng; Yuan, Qunwei

2018-03-01

In order to study the preparation method of gear fatigue load spectrum for loaders, the load signal of four typical working conditions of loader is collected. The signal that reflects the law of load change is obtained by preprocessing the original signal. The torque of the drive axle is calculated by using the rain flow counting method. According to the operating time ratio of each working condition, the two dimensional load spectrum based on the real working conditions of the drive axle of loader is established by the cycle extrapolation and synthesis method. The two-dimensional load spectrum is converted into one-dimensional load spectrum by means of the mean of torque equal damage method. Torque amplification includes the maximum load torque of the main reduction gear. Based on the theory of equal damage, the accelerated cycles are calculated. In this way, the load spectrum of the loading condition of the drive axle is prepared to reflect loading condition of the loader. The load spectrum can provide reference for fatigue life test and life prediction of loader drive axle.

Daily Cycle of Air Temperature and Surface Temperature in Stone Forest

NASA Astrophysics Data System (ADS)

Wang, K.; Li, Y.; Wang, X.; Yuan, M.

2013-12-01

Urbanization is one of the most profound human activities that impact on climate change. In cities, where are highly artificial areas, the conflict between human activity and natural climate is particularly prominent. Urban areas always have the larger area of impervious land, the higher consumption of greenhouse gases, more emissions of anthropogenic heat and air pollution, all contribute to the urban warming phenomena. Understanding the mechanisms causing a variety of phenomena involved in the urban warming is critical to distinguish the anthropogenic effect and natural variation in the climate change. However, the exact dynamics of urban warming were poorly understood, and effective control strategies are not available. Here we present a study of the daily cycle of air temperature and surface temperature in Stone Forest. The specific heat of the stones in the Stone Forest and concrete of the man-made structures within the cities are approximate. Besides, the height of the Stone Forest and the height of buildings within the city are also similar. As a scenic area, the Stone Forest is being preserved and only opened for sightseeing. There is no anthropogenic heat, as well air pollution within the Stone Forest. The thermal environment in Stone Forest can be considered to be a simulation of thermal environment in the city, which can reveal the effect of man-made structures on urban thermal environment. We conducted the field studies and numerical analysis in the Stone Forest for 4 typical urban morphology and environment scenarios, including high-rise compact cities, low-rise sparse cities, garden cities and isolated single stone. Air temperature and relative humidity were measured every half an hour in 15 different locations, which within different spatial distribution of stones and can represent the four urban scenarios respectively. At the same time, an infrared camera was used to take thermal images and get the hourly surface temperatures of stones and vegetation in the measurement area. The differences of the daily cycle of air temperature and surface temperature in these four scenarios show a significant impact of urban man-made structures on the dynamics of urban thermal environment.

A speed guidance strategy for multiple signalized intersections based on car-following model

NASA Astrophysics Data System (ADS)

Tang, Tie-Qiao; Yi, Zhi-Yan; Zhang, Jian; Wang, Tao; Leng, Jun-Qiang

2018-04-01

Signalized intersection has great roles in urban traffic system. The signal infrastructure and the driving behavior near the intersection are paramount factors that have significant impacts on traffic flow and energy consumption. In this paper, a speed guidance strategy is introduced into a car-following model to study the driving behavior and the fuel consumption in a single-lane road with multiple signalized intersections. The numerical results indicate that the proposed model can reduce the fuel consumption and the average stop times. The findings provide insightful guidance for the eco-driving strategies near the signalized intersections.

Direct and indirect urban water footprints of the United States

NASA Astrophysics Data System (ADS)

Chini, Christopher M.; Konar, Megan; Stillwell, Ashlynn S.

2017-01-01

The water footprint of the urban environment is not limited to direct water consumption (i.e., municipal supplies); embedded water in imported resources, or virtual water transfers, provides an additional component of the urban water footprint. Using empirical data, our analysis extends traditional urban water footprinting analysis to quantify both direct and indirect urban resources for the United States. We determine direct water volumes and their embedded energy through open records requests of water utilities. The indirect component of the urban water footprint includes water indirectly consumed through energy and food, relating to the food-energy-water nexus. We comprehensively quantify the indirect water footprint for 74 metropolitan statistical areas through the combination of various databases, including the Commodity Flow Survey of the U.S. Census Bureau, the U.S. Department of Agriculture, the Water Footprint Network, and the Energy Information Administration. We then analyze spatial heterogeneity in both direct and indirect water footprints, determining the average urban water footprint in the United States to be 1.64 million gallons of water per person per year [6200 m3/person/yr or 17,000 L/person/d], dominated by indirect water. Additionally, our study of the urban water cycle extends beyond considering only water resources to include embedded energy and equivalent carbon dioxide emissions. The inclusion of multiple sectors of the urban water cycle and their underlying processes provides important insights to the overall urban environment, the interdependencies of the food-energy-water nexus, and water resource sustainability. Our results provide opportunities for benchmarking the urban energy-water nexus, water footprints, and climate change potential.

Driving behaviour in adults with attention deficit/hyperactivity disorder.

PubMed

Groom, Madeleine J; van Loon, Editha; Daley, David; Chapman, Peter; Hollis, Chris

2015-07-28

Little is known about the impact of cognitive impairments on driving in adults with ADHD. The present study compared the performance of adults with and without ADHD in a driving simulator on two different routes: an urban route which we hypothesised would exacerbate weak impulse control in ADHD and a motorway route, to challenge deficits in sustained attention. Adults with (n = 22, 16 males) and without (n = 21, 18 males) ADHD completed a simulated driving session while eye movement data were recorded simultaneously. Participants also completed the Manchester Driving Behaviour Questionnaire (DBQ) and the Conners Adult ADHD Rating Scale (CAARS). Measures of driving performance included average speed, proportion distance travelled over speed limit (speeding) and lane deviation. These variables and the eye movement measures (spread of fixations, mean fixation duration) were compared between groups and routes. Also, driving behaviours, including responses to programmed events, were categorised and the frequencies within categories were compared between groups. Finally, speech analysis was performed to compare emotional verbal expressions during driving between groups. ADHD participants reported significantly more Violations and Lapses on the DBQ than control participants and significantly more accidents. Average speed and speeding were also higher but did not interact with route type. ADHD participants showed poorer vehicle control, greater levels of frustration with other road users (including greater frequencies of negative comments) and a trend for less safe driving when changing lanes/overtaking on the motorway. These effects were predicted by hyperactive/impulsive CAARS scores. They were also more likely to cause a crash/near miss when an event occurred on the urban route. The results suggest that difficulty regulating and controlling impulsive behavior, reflected in speeding, frustration with other road users, less safety when changing lanes on the motorway and a greater likelihood of an accident following an unexpected event, underlie impaired driving in ADHD. Hyperactivity/impulsivity symptoms correlated with these indices. Deficits in sustained attention seemed to play a lesser role in this particular study, although further research is needed to determine whether effects on attention emerge over longer periods of time and/or are influenced by the novelty of the simulator environment.

An observational study of driving distractions on urban roads in Spain.

PubMed

Prat, F; Planes, M; Gras, M E; Sullman, M J M

2015-01-01

The present research investigated the prevalence of driver engagement in secondary tasks and whether there were any differences by age and gender, as well as day of the week and time of the day. Two independent researchers observed 6578 drivers at nine randomly selected urban locations in Girona, Spain. Nearly 20% of the drivers observed were engaged in some type of secondary task, with the most common being: conversing with a passenger (11.1%), smoking (3.7%) and talking on a handheld mobile phone (1.3%). Surprisingly there were no differences by gender, but there were age-related differences with younger drivers being more frequently observed engaged in a number of different types of secondary tasks while driving (i.e. drinking, talking on a handheld mobile phone, and texting or keying numbers). Logistic regression showed that younger drivers, and to a lesser extent middle-age drivers, were significantly more likely to be observed engaged in a technological distraction than older drivers. Conversely, non-technological distractions were significantly predicted by day of the week, time of the day and location. A substantial number of the drivers observed in this study were putting themselves at an increased risk of becoming involved in a crash by engaging in non-driving related tasks at the same time as driving. Furthermore, the higher crash rate among young drivers may be partially accounted for by their more frequent engagement in some types of secondary tasks while driving. Copyright © 2014. Published by Elsevier Ltd.

A life cycle greenhouse gas inventory of a tree production system

Treesearch

Alissa Kendall; E. Gregory McPherson

2012-01-01

PurposeThis study provides a detailed, process-based life cycle greenhouse gas (GHG) inventory of an ornamental tree production system for urban forestry. The success of large-scale tree planting initiatives for climate protection depends on projects being net sinks for CO2 over their entire life cycle....

A streamlined sustainability assessment tool for improved decision making in the urban water industry.

PubMed

Schulz, Matthias; Short, Michael D; Peters, Gregory M

2012-01-01

Water supply is a key consideration in sustainable urban planning. Ideally, detailed quantitative sustainability assessments are undertaken during the planning stage to inform the decision-making process. In reality, however, the significant time and cost associated with undertaking such detailed environmental and economic assessments is often cited as a barrier to wider implementation of these key decision support tools, particularly for decisions made at the local or regional government level. In an attempt to overcome this barrier of complexity, 4 water service providers in Melbourne, Australia, funded the development of a publicly available streamlined Environmental Sustainability Assessment Tool, which is aimed at a wide range of decision makers to assist them in broadening the type and number of water servicing options that can be considered for greenfield or backlog developments. The Environmental Sustainability Assessment Tool consists of a simple user interface and draws on life cycle inventory data to allow for rapid estimation of the environmental and economic performance of different water servicing scenarios. Scenario options can then be further prioritized by means of an interactive multicriteria analysis. The intent of this article is to identify the key issues to be considered in a streamlined sustainability assessment tool for the urban water industry, and to demonstrate the feasibility of generating accurate life cycle assessments and life cycle costings, using such a tool. We use a real-life case study example consisting of 3 separate scenarios for a planned urban development to show that this kind of tool can emulate life cycle assessments and life cycle costings outcomes obtained through more detailed studies. This simplified approach is aimed at supporting "sustainability thinking" early in the decision-making process, thereby encouraging more sustainable water and sewerage infrastructure solutions. Copyright © 2011 SETAC.

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

Ehleringer, James; Randerson, James; Lai, Chun-Ta

The objective of the proposed research was to collect data and develop models to improve our understanding of the role of drought and fire impacts on the terrestrial carbon cycle in the western US, including impacts associated with urban systems as they impacted regional carbon cycles. Using data we collected and a synthesis of other measurements, we developed new ways (a) to evaluate the representation of drought stress and fire emissions in the Community Land Model, (b) to model net ecosystem exchange combining ground level atmospheric observations with boundary layer theory, (c) to model upstream impacts of fire and fossilmore » fuel emissions on atmospheric carbon dioxide observations, and (d) to model carbon dioxide observations within urban systems and at the urban-wildland interfaces of forest ecosystems.« less

Reconnecting cities to the biosphere: stewardship of green infrastructure and urban ecosystem services.

PubMed

Andersson, Erik; Barthel, Stephan; Borgström, Sara; Colding, Johan; Elmqvist, Thomas; Folke, Carl; Gren, Åsa

2014-05-01

Within-city green infrastructure can offer opportunities and new contexts for people to become stewards of ecosystem services. We analyze cities as social-ecological systems, synthesize the literature, and provide examples from more than 15 years of research in the Stockholm urban region, Sweden. The social-ecological approach spans from investigating ecosystem properties to the social frameworks and personal values that drive and shape human interactions with nature. Key findings demonstrate that urban ecosystem services are generated by social-ecological systems and that local stewards are critically important. However, land-use planning and management seldom account for their role in the generation of urban ecosystem services. While the small scale patchwork of land uses in cities stimulates intense interactions across borders much focus is still on individual patches. The results highlight the importance and complexity of stewardship of urban biodiversity and ecosystem services and of the planning and governance of urban green infrastructure.

Advanced Materials, Technologies, and Complex Systems Analyses: Emerging Opportunities to Enhance Urban Water Security.

PubMed

Zodrow, Katherine R; Li, Qilin; Buono, Regina M; Chen, Wei; Daigger, Glen; Dueñas-Osorio, Leonardo; Elimelech, Menachem; Huang, Xia; Jiang, Guibin; Kim, Jae-Hong; Logan, Bruce E; Sedlak, David L; Westerhoff, Paul; Alvarez, Pedro J J

2017-09-19

Innovation in urban water systems is required to address the increasing demand for clean water due to population growth and aggravated water stress caused by water pollution, aging infrastructure, and climate change. Advances in materials science, modular water treatment technologies, and complex systems analyses, coupled with the drive to minimize the energy and environmental footprints of cities, provide new opportunities to ensure a resilient and safe water supply. We present a vision for enhancing efficiency and resiliency of urban water systems and discuss approaches and research needs for overcoming associated implementation challenges.

The application of a Web-geographic information system for improving urban water cycle modelling.

PubMed

Mair, M; Mikovits, C; Sengthaler, M; Schöpf, M; Kinzel, H; Urich, C; Kleidorfer, M; Sitzenfrei, R; Rauch, W

2014-01-01

Research in urban water management has experienced a transition from traditional model applications to modelling water cycles as an integrated part of urban areas. This includes the interlinking of models of many research areas (e.g. urban development, socio-economy, urban water management). The integration and simulation is realized in newly developed frameworks (e.g. DynaMind and OpenMI) and often assumes a high knowledge in programming. This work presents a Web based urban water management modelling platform which simplifies the setup and usage of complex integrated models. The platform is demonstrated with a small application example on a case study within the Alpine region. The used model is a DynaMind model benchmarking the impact of newly connected catchments on the flooding behaviour of an existing combined sewer system. As a result the workflow of the user within a Web browser is demonstrated and benchmark results are shown. The presented platform hides implementation specific aspects behind Web services based technologies such that the user can focus on his main aim, which is urban water management modelling and benchmarking. Moreover, this platform offers a centralized data management, automatic software updates and access to high performance computers accessible with desktop computers and mobile devices.

Flood analysis in mixed-urban areas reflecting interactions with the complete water cycle through coupled hydrologic-hydraulic modelling.

PubMed

Sto Domingo, N D; Refsgaard, A; Mark, O; Paludan, B

2010-01-01

The potential devastating effects of urban flooding have given high importance to thorough understanding and management of water movement within catchments, and computer modelling tools have found widespread use for this purpose. The state-of-the-art in urban flood modelling is the use of a coupled 1D pipe and 2D overland flow model to simultaneously represent pipe and surface flows. This method has been found to be accurate for highly paved areas, but inappropriate when land hydrology is important. The objectives of this study are to introduce a new urban flood modelling procedure that is able to reflect system interactions with hydrology, verify that the new procedure operates well, and underline the importance of considering the complete water cycle in urban flood analysis. A physically-based and distributed hydrological model was linked to a drainage network model for urban flood analysis, and the essential components and concepts used were described in this study. The procedure was then applied to a catchment previously modelled with the traditional 1D-2D procedure to determine if the new method performs similarly well. Then, results from applying the new method in a mixed-urban area were analyzed to determine how important hydrologic contributions are to flooding in the area.

Experimental research made during a city cycle on the feasibility of electrically charged SI engines

NASA Astrophysics Data System (ADS)

Kocsis, Levente B.; Burnete, Nicolae

2014-06-01

The paper presents experimental research on performance improvements in a city cycle (operating mostly transient) of a compact class vehicle equipped with a turbocharged SI engine which had attached an electric charger, to improve engine response at low operational speeds. During tests, functional parameters, energy consumption of the electric charger and vehicle performances were measured while driving in two operating conditions: with active and inactive electric charger. The tests were carried out on a well-defined path, in the same driving style, by the same driver.

Cars Gone Wild: The Major Contributor to Unintended Acceleration in Automobiles is Pedal Error.

PubMed

Schmidt, Richard A; Young, Douglas E

2010-01-01

"Unintended-acceleration" automobile accidents typically begin when the driver first enters the car, starts the engine, and intends to press his/her right foot on the brake while shifting from Park to a drive gear (Drive or Reverse). The driver reports an unintended (uncommanded) full-throttle acceleration, coupled with a loss of braking, until the episode ends in a crash. Pedal misapplications - where the right foot contacts the accelerator instead of the brake that was intended - have been linked to these accidents (Schmidt, 1989, 1993) which, in the 1980s, were thought to occur only at the start of a driving cycle (and/or with the car in Park). But, in 1997, we identified over 200 pedal errors as the cause of accidents reported in the North Carolina database; these crashes occurred during the driving cycle (Schmidt et al., 1997), and/or with the vehicle in a gear other than Park. Our present work provides a more thorough analysis of these North Carolina Police Accident Reports from 1979 to 1995. The vast majority of pedal misapplications (over 92%) (a) occurred during the driving cycle, (b) were generally in "unhurried" conditions, and (c) were categorically separate from those events referred to as unintended-acceleration episodes at start-up. These ideas are explanatory for the recent (2009-2010) surge of unintended-acceleration reports, perhaps even suggesting that all of these crashes are caused by pedal errors, and that none of them are based on some vehicle defect(s).

Co-adapting societal and ecological interactions following large disturbances in urban park woodlands

Treesearch

Margaret Carreiro; Wayne Zipperer

2011-01-01

The responses of urban park woodlands to large disturbances provide the opportunity to identify and examine linkages in social-ecological systems in urban landscapes.We propose that the Panarchy model consisting of hierarchically nested adaptive cycles provides a useful framework to evaluate those linkages.We use two case studies as examples – Cherokee Park in...

Effects of urban land-use change on biogeochemical cycles

Treesearch

Richard V. Pouyat; Diane E. Pataki; Kenneth T. Belt; Peter M. Groffman; John Hom; Lawrence E. Band

2007-01-01

Urban land-use change, the conversion of agricultural recand natural ecosystems to human settlements, has become an important component of global change. Virtually all of the projected increase in the world's population is expected to occur in cities so that by the year 2007 more than half of the global population is expected to live in urban areas (United Nations...

40 CFR 86.115-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission.... time relationships. They each consist of a distinct nonrepetitive series of idle, acceleration, cruise...

40 CFR 86.115-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission.... time relationships. They each consist of a distinct nonrepetitive series of idle, acceleration, cruise...

40 CFR 86.115-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2012 CFR

2012-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission.... time relationships. They each consist of a distinct nonrepetitive series of idle, acceleration, cruise...

Urbanization and human health in urban India: institutional analysis of water-borne diseases in Ahmedabad.

PubMed

Saravanan, V S; Ayessa Idenal, Marissa; Saiyed, Shahin; Saxena, Deepak; Gerke, Solvay

2016-10-01

Diseases are rapidly urbanizing. Ageing infrastructures, high levels of inequality, poor urban governance, rapidly growing economies and highly dense and mobile populations all create environments rife for water-borne diseases. This article analyzes the role of institutions as crosscutting entities among a myriad of factors that breed water-borne diseases in the city of Ahmedabad, India. It applies 'path dependency' and a 'rational choice' perspective to understand the factors facilitating the breeding of diseases. This study is based on household surveys of approximately 327 households in two case study wards and intermittent interviews with key informants over a period of 2 years. Principle component analysis is applied to reduce the data and convert a set of observations, which potentially correlate with each other, into components. Institutional analyses behind these components reveal the role of social actors in exploiting the deeply rooted inefficiencies affecting urban health. This has led to a vicious cycle; breaking this cycle requires understanding the political dynamics that underlie the exposure and prevalence of diseases to improve urban health. © The Author 2016. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Suitability of Synthetic Driving Profiles from Traffic Micro-Simulation for Real-World Energy Analysis: Preprint

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

Hou, Yunfei; Wood, Eric; Burton, Evan

A shift towards increased levels of driving automation is generally expected to result in improved safety and traffic congestion outcomes. However, little empirical data exists to estimate the impact that automated driving could have on energy consumption and greenhouse gas emissions. In the absence of empirical data on differences between drive cycles from present day vehicles (primarily operated by humans) and future vehicles (partially or fully operated by computers) one approach is to model both situations over identical traffic conditions. Such an exercise requires traffic micro-simulation to not only accurately model vehicle operation under high levels of automation, but alsomore » (and potentially more challenging) vehicle operation under present day human drivers. This work seeks to quantify the ability of a commercial traffic micro-simulation program to accurately model real-world drive cycles in vehicles operated primarily by humans in terms of driving speed, acceleration, and simulated fuel economy. Synthetic profiles from models of freeway and arterial facilities near Atlanta, Georgia, are compared to empirical data collected from real-world drivers on the same facilities. Empirical and synthetic drive cycles are then simulated in a powertrain efficiency model to enable comparison on the basis of fuel economy. Synthetic profiles from traffic micro-simulation were found to exhibit low levels of transient behavior relative to the empirical data. Even with these differences, the synthetic and empirical data in this study agree well in terms of driving speed and simulated fuel economy. The differences in transient behavior between simulated and empirical data suggest that larger stochastic contributions in traffic micro-simulation (relative to those present in the traffic micro-simulation tool used in this study) are required to fully capture the arbitrary elements of human driving. Interestingly, the lack of stochastic contributions from models of human drivers in this study did not result in a significant discrepancy between fuel economy simulations based on synthetic and empirical data; a finding with implications on the potential energy efficiency gains of automated vehicle technology.« less

A comparison between developed and developing countries in terms of urban land use change effects on nitrogen cycle: Paris and São Paulo metropolitan areas

NASA Astrophysics Data System (ADS)

Nardoto, Gabriela; Svirejeva-Hopkin, Anastasia; Martinelli, Luiz Antonio

2010-05-01

Urbanization is considered one of the most powerful and characteristic anthropogenic forces on Earth in the 21st century. Although, currently, cities occupy only about 2 percent of the Earth's land surface, they are home to over 50 percent of the world's population. While in cities of some developed countries, urban population might stabilize or even slightly decrease, its rate of growth in developing countries is faster than in the industrialized nations. Such increase is accompanied by growing energy production, increased food demand, expanding transportation and industrialization. Although agricultural production is by far the largest cause of the doubling in the amount of reactive nitrogen entering the biospheric cycle compared to pre-industrial conditions, nowadays more than half of the crops produced in rural areas are consumed in urban zones. Having in mind that there is a clear global trend towards urbanization and growing urban areas, the objective of this study was to compare major nitrogen fluxes between a mega city situated in a developing country (São Paulo Metropolitan Area - SPMA) in Brazil with one of the largest city of highly industrialized Europe (Paris Metropolitan Area - PMA). We make the first step in producing a detailed N mass balance for the SPMA and PMA in order to estimate the magnitude of major fluxes across the urban landscape and see how N cycling vary among urban system components. This effort may help to highlight differences between developing and developed areas and subsidize the formulation of public policies towards reduction of N related pollution of recipient systems. The N mass balance showed the SPMA as a net source of nitrogen, emitting in total about 93.5 Gg of N per year, or about 4750 g of N per capita. Most N inputs to the SPMA are directly related to food consumption, N in wastewater and landfills. These fluxes are quite amendable to management efforts to reduce N input to the receiver component of the urban ecosystem (rivers and soil). For example treated sewage effluent could be used as a source of N for some crops, especially vegetables. PMA is also a source of reactive nitrogen, emitting in total about 32 Gg of N per year, or about 3000 g of N per capita, being the major part attributed to the atmospheric emissions from transportation and energy. An important outcome of this study has been the identification of several key uncertainties regarding the N budget that require further research for either developed and developing regions studied. The following uncertainties of N cycling in an urban system need better understanding: the mechanisms of dry-deposition processes in urban systems with patchy vegetation; high NOx emissions and the increase in travel distance of smaller particles coming from modern engines; and complex patterns of air flow in the dense build-up areas. Urban soil N dynamics is very uncertain, while soil represents a major sink of N in natural ecosystems. Ultimately, the challenge is to integrate human choices and ecosystem dynamics into a multidisciplinary model of biogeochemical cycling in urban ecosystems, focusing as a first step on the quantitatively evaluating the mutual relationship between urban land-use changes and natural ecosystem from the standpoint of global N balance. To develop those schemes will require the construction of detailed ecosystem-level N balances, an in-depth understanding of the interplay of inputs, geographical and climatic factors, nonspecific management practices, and deliberate N management practices that control the fate of N in urban landscapes.

Command History, 1970. Volume 1. Sanitized

DTIC Science & Technology

1970-01-01

Increased spending would drive up local prices, and the hoarding of rice would drive up food prices in urban areas. The introduction of counterfeit money ...essential assetR of food, money , manpower, concealment, and intelligence which the enemy needed to continue the war. The majority of the population and the...Communist line. (C) The VCI had two missions. The first was to provide military units with the money , food, recruits, intelligence, refuge, and guides without

Advancing approaches for multi-year high-frequency monitoring of temporal and spatial variability in carbon cycle fluxes and drivers in freshwater lakes

NASA Astrophysics Data System (ADS)

Desai, A. R.; Reed, D. E.; Dugan, H. A.; Loken, L. C.; Schramm, P.; Golub, M.; Huerd, H.; Baldocchi, A. K.; Roberts, R.; Taebel, Z.; Hart, J.; Hanson, P. C.; Stanley, E. H.; Cartwright, E.

2017-12-01

Freshwater ecosystems are hotspots of regional to global carbon cycling. However, significant sample biases limit our ability to quantify and predict these fluxes. For lakes, scaled flux estimates suffer biased sampling toward 1) low-nutrient pristine lakes, 2) infrequent temporal sampling, 3) field campaigns limited to the growing season, and 4) replicates limited to near the center of the lake. While these biases partly reflect the realities of ecological sampling, there is a need to extend observations towards the large fraction of freshwater systems worldwide that are impaired by human activities and those facing significant interannual variability owing to climatic change. Also, for seasonally ice-covered lakes, much of the annual budget of carbon fluxes is thought to be explained by variation in the shoulder seasons of spring ice melt and fall turnover. Recent advances in automated, continuous multi-year temporal sampling coupled with rapid methods for spatial mapping of CO2 fluxes has strong potential to rectify these sampling biases. Here, we demonstrate these advances in an eutrophic seasonally-ice covered lake with an urban shoreline and agricultural watershed. Multiple years of half-hourly eddy covariance flux tower observations from two locations are coupled with frequent spatial samples of these fluxes and drivers by speedboat, floating chamber fluxes, automated buoy-based monitoring of lake nutrient and physical profiles, and ensemble of physical-ecosystem models. High primary productivity in the water column leads to an average net carbon sink during the growing season in much of the lake, but annual net carbon fluxes show the lake can act as an annual source or a sink of carbon depending the timing of spring and fall turnover. Trophic interactions and internal waves drive shorter-term variation while nutrients and biology drive seasonal variation. However, discrepancies remain among methods to quantify fluxes, requiring further investigation.

Importance of CME Radial Expansion on the Ability of Slow CMEs to Drive Shocks

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

Lugaz, Noé; Farrugia, Charles J.; Winslow, Reka M.

Coronal mass ejections (CMEs) may disturb the solar wind by overtaking it or expanding into it, or both. CMEs whose front moves faster in the solar wind frame than the fast magnetosonic speed drive shocks. Such shocks are important contributors to space weather, by triggering substorms, compressing the magnetosphere, and accelerating particles. In general, near 1 au, CMEs with speed greater than about 500 km s{sup −1} drive shocks, whereas slower CMEs do not. However, CMEs as slow as 350 km s{sup −1} may sometimes, although rarely, drive shocks. Here we study these slow CMEs with shocks and investigate themore » importance of CME expansion in contributing to their ability to drive shocks and in enhancing shock strength. Our focus is on CMEs with average speeds under 375 km s{sup −1}. From Wind measurements from 1996 to 2016, we find 22 cases of such shock-driving slow CMEs, and for about half of them (11 out of the 22), the existence of the shock appears to be strongly related to CME expansion. We also investigate the proportion of all CMEs with speeds under 500 km s{sup −1} with and without shocks in solar cycles 23 and 24, depending on their speed. We find no systematic difference, as might have been expected on the basis of the lower solar wind and Alfvén speeds reported for solar cycle 24 versus 23. The slower expansion speed of CMEs in solar cycle 24 might be an explanation for this lack of increased frequency of shocks, but further studies are required.« less

Micropollutants in urban watersheds : substance flow analysis as management tool

NASA Astrophysics Data System (ADS)

Rossi, L.; Copin, P. J.; Barry, A. D.; Bader, H.-P.; Scheidegger, R.; Chèvre, N.

2009-04-01

Micropollutants released by cities into water are of increasing concern as they are suspected of inducing long-term effects on both aquatic organisms and humans (eg., hormonally active substances). Substances found in the urban water cycle have different sources in the urban area and different fates in this cycle. For example, the pollutants emitted from traffic, like copper or PAHs get to surface water during rain events often without any treatment. Pharmaceuticals resulting from human medical treatments get to surface water mainly through wastewater treatment plants, where they are only partly treated and eliminated. One other source of contamination in urban areas for these compounds are combined sewer overflows (CSOs). Once in the receiving waters (lakes, rivers, groundwater), these substances may re-enter the cycle through drinking water. It is therefore crucial to study the behaviour of micropollutants in the urban water cycle and to get flexible tools for urban water management. Substance flow analysis (SFA) has recently been proposed as instrument for water pollution management in urban water systems. This kind of analysis is an extension of material flow analysis (MFA) originally developed in the economic sector and later adapted to regional investigations. In this study, we propose to test the application of SFA for a large number of classes of micropollutants to evaluate its use for urban water management. We chose the city of Lausanne as case study since the receiving water of this city (Lake Geneva) is an important source of drinking water for the surrounding population. Moreover a profound system-knowledge and many data were available, both on the sewer system and the water quality. We focus our study on one heavy metal (copper) and four pharmaceuticals (diclofenac, ibuprofen, carbamazepine and naproxen). Results conducted on copper reveals that around 1500 kg of copper enter the aquatic compartment yearly. This amount contributes to sediment enrichment, which may pose a long-term risk for the benthic organisms. The major sources (total of 73%) of copper in receiving surface water are roofs and contact lines of trolleybuses. Thus technical solutions have to be found to manage this specific source of contamination. Application of SFA approach to four pharmaceuticals reveals that CSOs represent an important source of contamination: Between 14% (carbamazepine) and 61% (ibuprofen) of the total annual loads of Lausanne city to the Lake are due to CSOs. These results will help in defining the best management strategy to limit Lake Geneva contamination. SFA is thus a promising tool for integrated urban water management.

40 CFR 86.515-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2014 CFR

2014-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission... nonrepetitive series of idle, acceleration, cruise, and deceleration modes of various time sequences and rates...

40 CFR 86.515-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2012 CFR

2012-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission... nonrepetitive series of idle, acceleration, cruise, and deceleration modes of various time sequences and rates...

40 CFR 86.515-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission... nonrepetitive series of idle, acceleration, cruise, and deceleration modes of various time sequences and rates...

40 CFR 86.515-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission... nonrepetitive series of idle, acceleration, cruise, and deceleration modes of various time sequences and rates...

AQUATIC ECOSYSTEMS,

EPA Science Inventory

Aquatic ecosystems are a vital part of the urban water cycle (and of urban areas more broadly), and, if healthy, provide a range of goods and services valued by humans (Meyer 1997). For example, aquatic ecosystems (e.g., rivers, lakes, wetlands) provide potable water, food resou...

Common Traffic Violations of Bus Drivers in Urban China: An Observational Study

PubMed Central

Yang, Rendong; Huang, Yuanxiu; Zhang, Lin; Ning, Peishan; Cheng, Xunjie; Schwebel, David C.

2015-01-01

Objective To report common traffic violations in bus drivers and the factors that influence those violations in urban China. Methods We conducted an observational study to record three types of traffic violations among bus drivers in Changsha City, China: illegal stopping at bus stations, violating traffic light signals, and distracted driving. The behaviors of bus drivers on 32 routes (20% of bus routes in the city) were observed. A two-level Poisson regression examined factors that predicted bus driver violations. Results The incidence of illegal stopping at bus stations was 20.2%. Illegal stopping was less frequent on weekends, sunny days, and at stations with cameras, with adjusted incidence rate ratios (IRRs) of 0.81, 0.65 and 0.89, respectively. The incidence of violating traffic light signals was 2.2%, and was lower on cloudy than sunny days (adjusted IRR: 0.60). The incidence of distracted driving was 3.3%. The incidence of distracted driving was less common on cloudy days, rainy or snowy days, and foggy/windy/dusty days compared to sunny days, with adjusted IRRs of 0.54, 0.55 and 0.07, respectively. Conclusion Traffic violations are common in bus drivers in urban China and they are associated with the date, weather, and presence of traffic cameras at bus station. Further studies are recommended to understand the behavioral mechanisms that may explain bus driver violations and to develop feasible prevention measures. PMID:26372105

Revealed access to haemodialysis facilities in northeastern Iran: Factors that matter in rural and urban areas.

PubMed

Kiani, Behzad; Bagheri, Nasser; Tara, Ahmad; Hoseini, Benyamin; Tabesh, Hamed; Tara, Mahmood

2017-11-07

Poor access to haemodialysis facilities is associated with high mortality and morbidity rates. This study investigated factors affecting revealed access to the haemodialysis facilities considering patients living in rural and urban areas without any haemodialysis facility (Group A) and those living urban areas with haemodialysis facilities (Group B). This study is based on selfreported Actual Access Time (AAT) to referred haemodialysis facilities and other information regarding travel to haemodialysis facilities from patients. All significant variables on univariate analysis were entered into a univariate general linear model in order to identify factors associated with AAT. Both spatial (driving time and distance) and non-spatial factors (sex, income level, caregivers, transportation mode, education level, ethnicity and personal vehicle ownership) influenced the revealed access identified in Group A. The non-spatial factors for Group B patients were the same as for Group A, but no spatial factor was identified in Group B. It was found that accessibility is strongly underestimated when driving time is chosen as accessibility measure to haemodialysis facilities. Analysis of revealed access determinants provides policymakers with an appropriate decision base for making appropriate decisions and finding solutions to decrease the access time for patients under haemodialysis therapy. Driving time alone is not a good proxy for measuring access to haemodialysis facilities as there are many other potential obstacles, such as women's special travel problems, poor other transportation possibilities, ethnicity disparities, low education levels, low caregiver status and low-income.

0-6629 : Texas specific drive cycles and idle emissions rates for using with EPA's MOVES model, [project summary].

DOT National Transportation Integrated Search

2013-08-01

The U.S. Environmental Protection Agencys : newest emissions model, Motor Vehicle Emission : Simulator (MOVES), enables users to use local : drive schedules(representative vehicle speed : profiles) in order to perform an accurate analysis : of emi...

Eco Assist Techniques through Real-time Monitoring of BEV Energy Usage Efficiency

PubMed Central

Kim, Younsun; Lee, Ingeol; Kang, Sungho

2015-01-01

Energy efficiency enhancement has become an increasingly important issue for battery electric vehicles. Even if it can be improved in many ways, the driver’s driving pattern strongly influences the battery energy consumption of a vehicle. In this paper, eco assist techniques to simply implement an energy-efficient driving assistant system are introduced, including eco guide, eco control and eco monitoring methods. The eco guide is provided to control the vehicle speed and accelerator pedal stroke, and eco control is suggested to limit the output power of the battery. For eco monitoring, the eco indicator and eco report are suggested to teach eco-friendly driving habits. The vehicle test, which is done in four ways, consists of federal test procedure (FTP)-75, new european driving cycle (NEDC), city and highway cycles, and visual feedback with audible warnings is provided to attract the driver’s voluntary participation. The vehicle test result shows that the energy usage efficiency can be increased up to 19.41%. PMID:26121611

Response of vegetation phenology to urbanization in the conterminous United States.

PubMed

Li, Xuecao; Zhou, Yuyu; Asrar, Ghassem R; Mao, Jiafu; Li, Xiaoma; Li, Wenyu

2017-07-01

The influence of urbanization on vegetation phenology is gaining considerable attention due to its implications for human health, cycling of carbon and other nutrients in Earth system. In this study, we examined the relationship between change in vegetation phenology and urban size, an indicator of urbanization, for the conterminous United States. We studied more than 4500 urban clusters of varying size to determine the impact of urbanization on plant phenology, with the aids of remotely sensed observations since 2003-2012. We found that phenology cycle (changes in vegetation greenness) in urban areas starts earlier (start of season, SOS) and ends later (end of season, EOS), resulting in a longer growing season length (GSL), when compared to the respective surrounding urban areas. The average difference of GSL between urban and rural areas over all vegetation types, considered in this study, is about 9 days. Also, the extended GSL in urban area is consistent among different climate zones in the United States, whereas their magnitudes are varying across regions. We found that a tenfold increase in urban size could result in an earlier SOS of about 1.3 days and a later EOS of around 2.4 days. As a result, the GSL could be extended by approximately 3.6 days with a range of 1.6-6.5 days for 25th ~ 75th quantiles, with a median value of about 2.1 days. For different vegetation types, the phenology response to urbanization, as defined by GSL, ranges from 1 to 4 days. The quantitative relationship between phenology and urbanization is of great use for developing improved models of vegetation phenology dynamics under future urbanization, and for developing change indicators to assess the impacts of urbanization on vegetation phenology. © 2016 John Wiley & Sons Ltd.

Pleistocene glacial cycles drive isolation, gene flow and speciation in the high-elevation Andes.

PubMed

Nevado, Bruno; Contreras-Ortiz, Natalia; Hughes, Colin; Filatov, Dmitry A

2018-06-04

Mountain ranges are amongst the most species-rich habitats, with many large and rapid evolutionary radiations. The tempo and mode of diversification in these systems are key unanswered questions in evolutionary biology. Here we study the Andean Lupinus radiation to understand the processes driving very rapid diversification in montane systems. We use genomic and transcriptomic data of multiple species and populations, and apply phylogenomic and demographic analyses to test whether diversification proceeded without interspecific gene flow - as expected if Andean orogeny and geographic isolation were the main drivers of diversification - or if diversification was accompanied by gene flow, in which case other processes were probably involved. We uncover several episodes of gene flow between species, including very recent events likely to have been prompted by changes in habitat connectivity during Pleistocene glacial cycles. Furthermore, we find that gene flow between species was heterogeneously distributed across the genome. We argue that exceptionally fast diversification of Andean Lupinus was partly a result of Late Pleistocene glacial cycles, with associated cycles of expansion and contraction driving geographic isolation or secondary contact of species. Furthermore, heterogeneous gene flow across the genome suggests a role for selection and ecological speciation in rapid diversification in this system. © 2018 The Authors New Phytologist © 2018 New Phytologist Trust.

Modeling the effects of caffeine on the sleep/ wake cycle.

PubMed

Daniello, Allison; Fievisohn, Elizabeth; Gregory, T Stan

2012-01-01

Caffeine is present in many products consumed daily, including coffee, soda, and chocolate, and is known to delay the onset of sleepiness and cause sleep disturbances. It is an adenosine antagonist, inhibiting some hormones that promote sleep, and therefore promoting wakefulness. This paper proposes a model to incorporate the effects of caffeine on the sleep/wake cycle. The “flip-flop” model was used to model the sleep cycle, where switching between a sleep state and a wake state was nearly instantaneous. Sleep patterns were modeled based on the circadian rhythm and homeostatic drive, as was done by Rempe et al. (2010). The model demonstrated how the homeostatic drive and circadian rhythm interact to cause sleep and wakefulness. The effects of caffeine were incorporated to have a masking effect on the homeostatic drive, promoting wakefulness. Preliminary results showed that caffeine intake late in the evening caused the switch from wake to sleep to occur later than if no caffeine was present in the system. Additionally, the switch from wake to sleep was increasingly delayed with increased caffeine intake at the same time. This model is not yet validated, though potential studies for validation are proposed. This model presents an interesting method for incorporating the effects of caffeine on the sleep/wake cycle.

Carbon stocks in urban forest remnants: Atlanta and Baltimore as case studies. Chapter 5.

Treesearch

Ian D. Yesilonis; Richard V. Pouyat

2012-01-01

Urban environments influence carbon (C) and nitrogen (N) cycles of forest ecosystems by altering plant biomass, litter mass and chemistry, passive and active pools of C and N, and the occurrence and activity of decomposer organisms. It is difficult to determine the net effect of C storage due to the number of environmental factors exerting stress on urban forests....

Electromechanical systems with transient high power response operating from a resonant AC link

NASA Technical Reports Server (NTRS)

Burrows, Linda M.; Hansen, Irving G.

1992-01-01

The combination of an inherently robust asynchronous (induction) electrical machine with the rapid control of energy provided by a high frequency resonant AC link enables the efficient management of higher power levels with greater versatility. This could have a variety of applications from launch vehicles to all-electric automobiles. These types of systems utilize a machine which is operated by independent control of both the voltage and frequency. This is made possible by using an indirect field-oriented control method which allows instantaneous torque control in all four operating quadrants. Incorporating the AC link allows the converter in these systems to switch at the zero crossing of every half cycle of the AC waveform. This zero loss switching of the link allows rapid energy variations to be achieved without the usual frequency proportional switching loss. Several field-oriented control systems were developed by LeRC and General Dynamics Space Systems Division under contract to NASA. A description of a single motor, electromechanical actuation system is presented. Then, focus is on a conceptual design for an AC electric vehicle. This design incorporates an induction motor/generator together with a flywheel for peak energy storage. System operation and implications along with the associated circuitry are addressed. Such a system would greatly improve all-electric vehicle ranges over the Federal Urban Driving Cycle (FUD).

The carbon commute: Effects of urbanization on dissolved organic carbon quality on a suburban New England river network

NASA Astrophysics Data System (ADS)

Balch, E.; Robison, A.; Wollheim, W. M.

2017-12-01

Understanding anthropogenic influence on the sources and fluxes of carbon is necessary for interpreting the carbon cycle and contaminant transport throughout a river system. As urbanization increases worldwide, it is critical to understand how urbanization affects the carbon cycle so that we may be able to predict future changes. Rivers act as both transporters of terrestrial dissolved organic carbon (DOC) to coastal regions, and active transformers of DOC. The character (lability) of the carbon found within a river network is influenced by its sources and fluxes, as determined by the ecological processes, land use, and discharge, which vary throughout the network. We have characterized DOC quantity and quality throughout a suburban New England river network (Ipswich River, MA) in an attempt to provide a detailed picture of how DOC quality varies within a network, and how urbanization influences these changes. We conducted a synoptic survey of 45 sites over two hydrologically similar days in the Ipswich River network in northeast Massachusetts, USA. We collected discrete grab samples for DOC quantity and quality analyses. We also collected dissolved oxygen, conductivity, and nutrients (major anions and cations) as an extension of the synoptic survey. We plan to determine the source of the DOC by using excitation-emission matrices (EEMs), and specific UV absorption (SUVA) at 254 nm. These analyses will provide us with a detailed picture of how DOC quality varies within a network, and how urbanization influences these changes. Using land use data of the Ipswich River watershed, we are able to model the changes in DOC quality throughout the network. In highly urbanized headwaters, through the progressively more forested and wetland dominated main stem reaches, we expect to see the imprint of urbanization throughout the network due to its decreased lability. Studying the imprint of urbanization on DOC throughout a river network helps us complete our understanding of freshwater carbon processes. Rivers are an important component of the global carbon balance, and monitoring the effect of urbanization on the carbon cycle in freshwater systems is integral to understanding their role in the global carbon system.

Hydropedological Assessments of Parcel-Level Infiltration in an Arid Urban Ecosystem

EPA Science Inventory

Soil morphology and correspondent hydrologic data can contribute to qualifying and quantifying urban soil suitability and capacity to cycle stormwater runoff. We put particular emphasis on the possibility that residential parcels may manage their own stormwater on pervious yard ...

[Impact of driving cessation on daily transportation utility in elderly people with cognitive decline: a survey of patients in the memory clinic of an urban university hospital].

PubMed

Kawano, Naoko; Makino, Taeko; Suzuki, Yusuke; Umegaki, Hiroyuki

2009-09-01

In the present study our goal was to explore the impact of driving cessation on daily transportation utility in older people with cognitive decline. A total of 101 older persons participated in our survey of responding of a questionnaire about driving and other methods for traveling, administered at the memory clinic of the geriatric outpatient unit of Nagoya University Hospital. Of this total, 48 (47.5%) still had driving licenses, 16 (15.8%) had licenses that had expired, and 37 (36.6%) had no driving experience. The majority of license holders (77.1%) were active drivers, and we found that license holders tend to utilize public transport loss than older people without driving experience. Furthermore, among those who had ceased driving, there was a contrast in daily transportation utility between those with dementia and those without dementia, with the former accessing public transport less frequently. When clinicians advise drivers with dementia to cease driving, these patients need special attention to assist them in providing alternative ways of transportation.

Comparison of steady-state and transient CVS cycle emission of an automotive Stirling engine

NASA Technical Reports Server (NTRS)

Farrell, R. A.; Bolton, R. J.

1983-01-01

The Automotive Stirling Engine Development Program is to demonstrate a number of goals for a Stirling-powered vehicle. These goals are related to an achievement of specified maximum emission rates, a combined cycle fuel economy 30 percent better than a comparable internal-combustion engine-powered automobile, multifuel capability, competitive cost and reliability, and a meeting of Federal standards concerning noise and safety. The present investigation is concerned with efforts related to meeting the stringent emission goals. Attention is given to the initial development of a procedure for predicting transient CVS urban cycle gaseous emissions from steady-state engine data, taking into account the employment of the test data from the first-generation automotive Stirling engine. A large amount of steady-state data from three Mod I automotive Stirling engines were used to predict urban CVS cycle emissions for the Mod I Lerma vehicle.

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.

Sediment transport drives tidewater glacier periodicity.

PubMed

Brinkerhoff, Douglas; Truffer, Martin; Aschwanden, Andy

2017-07-21

Most of Earth's glaciers are retreating, but some tidewater glaciers are advancing despite increasing temperatures and contrary to their neighbors. This can be explained by the coupling of ice and sediment dynamics: a shoal forms at the glacier terminus, reducing ice discharge and causing advance towards an unstable configuration followed by abrupt retreat, in a process known as the tidewater glacier cycle. Here we use a numerical model calibrated with observations to show that interactions between ice flow, glacial erosion, and sediment transport drive these cycles, which occur independent of climate variations. Water availability controls cycle period and amplitude, and enhanced melt from future warming could trigger advance even in glaciers that are steady or retreating, complicating interpretations of glacier response to climate change. The resulting shifts in sediment and meltwater delivery from changes in glacier configuration may impact interpretations of marine sediments, fjord geochemistry, and marine ecosystems.The reason some of the Earth's tidewater glaciers are advancing despite increasing temperatures is not entirely clear. Here, using a numerical model that simulates both ice and sediment dynamics, the authors show that internal dynamics drive glacier variability independent of climate.

Emissions from U.S. waste collection vehicles.

PubMed

Maimoun, Mousa A; Reinhart, Debra R; Gammoh, Fatina T; McCauley Bush, Pamela

2013-05-01

This research is an in-depth environmental analysis of potential alternative fuel technologies for waste collection vehicles. Life-cycle emissions, cost, fuel and energy consumption were evaluated for a wide range of fossil and bio-fuel technologies. Emission factors were calculated for a typical waste collection driving cycle as well as constant speed. In brief, natural gas waste collection vehicles (compressed and liquid) fueled with North-American natural gas had 6-10% higher well-to-wheel (WTW) greenhouse gas (GHG) emissions relative to diesel-fueled vehicles; however the pump-to-wheel (PTW) GHG emissions of natural gas waste collection vehicles averaged 6% less than diesel-fueled vehicles. Landfill gas had about 80% lower WTW GHG emissions relative to diesel. Biodiesel waste collection vehicles had between 12% and 75% lower WTW GHG emissions relative to diesel depending on the fuel source and the blend. In 2011, natural gas waste collection vehicles had the lowest fuel cost per collection vehicle kilometer travel. Finally, the actual driving cycle of waste collection vehicles consists of repetitive stops and starts during waste collection; this generates more emissions than constant speed driving. Published by Elsevier Ltd.

Permanent magnet DC motor control by using arduino and motor drive module BTS7960

NASA Astrophysics Data System (ADS)

Syukriyadin, S.; Syahrizal, S.; Mansur, G.; Ramadhan, H. P.

2018-05-01

This study proposes a control system for permanent magnet DC (PMDC) motor. PMDC drive control system has two critical parameters: control and monitoring. Control system includes rotation speed control and direction of rotation of motor using motor drive module BTS7960. The PWM signal has a fixed frequency of waves with varying duty cycles (between 0% and 100%), so the motor rotation can be regulated gradually using a potentiometer already programmed on the Arduino Uno board. The motor rotation direction setting uses the H-bridge circuit method using a 3-way switch to set the direction of forward-reverse rotation of the motor. The monitoring system includes measurements of rotational speed, current, and voltage. Motor rotation speed can be adjusted from the armature voltage settings through the duty cycle PWM setting so that the motor speed can be increased or decreased by the desired duty cycle. From the unload PMDC motor test results it has also been shown that the torque of the motor is relatively constant when there is a change in speed from low rpm to high rpm or vice versa.

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.

Evaluation of vibration limits and mitigation techniques for urban construction : [summary].

DOT National Transportation Integrated Search

2013-10-01

Construction activities such as pile driving and : dynamic compaction of loose soils induce ground : and structure vibrations. Their effects may annoy : local populations, disturb sensitive equipment, or : reduce structures serviceability and dura...

Partial Derivatives, the Energy Crisis, and Urban Transportation: Calculus for Concerned Citizens

ERIC Educational Resources Information Center

Bent, Henry A.

1976-01-01

Presented is a method utilizing partial derivatives for determining the energy saved per dollar by substituting bicycling for driving a car while not reducing jobs dependent upon the auto industry. (SL)

77 FR 4276 - National Urban and Community Forestry Advisory Council

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-27

... Drive SW., Washington, DC 20250; Phone: (202) 205-7829. FOR FURTHER INFORMATION CONTACT: Nancy Stremple, 201 14th Street SW., Yates Building (1 Central) MS-1151, Washington, DC 20250-1151, phone (202) 205...

Energy and the Automobile.

ERIC Educational Resources Information Center

Waring, Gene

1980-01-01

Discussed is the automobile in terms of the Otto cycle, engine heat losses, internal engine losses, drive train losses, road power, and driving habits. Each of these topics is described and calculations are shown to aid the physics teacher in the use of the automobile in the physics classroom. (Author/DS)

Significant alteration of Critical Zone processes in urban watersheds: shifting from a transport-limited to a weathering-limited regime

NASA Astrophysics Data System (ADS)

Moore, J.; Bird, D. L.; Dobbis, S. K.; Woodward, G.

2016-12-01

Urban areas and associated impervious surface cover (ISC) are among the fastest growing land use types. Rapid growth of urban lands has significant implications for geochemical cycling and solute sources to streams, estuaries, and coastal waters. However, little work has been done to investigate the impacts of urbanization on Critical Processes, including on the export of solutes from urban watersheds. Despite observed elevated solute concentrations in urban streams in some previous studies, neither solute sources nor total solute fluxes have been quantified due to mixed bedrock geology, lack of a forested reference watershed, or the presence of point sources that confounded separation of anthropologic and natural sources. We investigated the geochemical signal of the urban built environment (e.g., roads, parking lots, buildings) in a set of five USGS-gaged watersheds across a rural (forested) to urban gradient in the Maryland Piedmont. These watersheds have ISC ranging from 0 to 25%, no point sources, and similar felsic bedrock chemistry. Weathering from the urban built environment and ISC produces dramatically higher solute concentrations in urban watersheds than in the forested watershed. Higher solute concentrations result in chemical weathering fluxes from urban watersheds that are 11-13 times higher than the forested watershed and are similar to fluxes from mountainous, weathering-limited watersheds rather than fluxes from transport-limited, dilute streams like the forested watershed. Weathering of concrete in urban watersheds produces geochemistry similar to weathering-limited watersheds with high concentrations of Ca2+, Mg2+, and DIC, which is similar to stream chemistry due to carbonate weathering. Road salt dissolution results in high Na+ and Cl- concentrations similar to evaporite weathering. Quantifying processes causing elevated solute fluxes from urban areas is essential to understanding cycling of Ca2+, Mg2+, and DIC in urban streams and in downgradient estuarine or coastal waters.

Urbanization prolongs hantavirus epidemics in cities

PubMed Central

Tian, Huaiyu; Hu, Shixiong; Chowell, Gerardo; Gao, Lidong; Li, Yapin; Yang, Huisuo; Li, Yidan; Yang, Qiqi; Tong, Xin; Huang, Ru; Bjornstad, Ottar N.; Xiao, Hong; Stenseth, Nils Chr.

2018-01-01

Urbanization and rural–urban migration are two factors driving global patterns of disease and mortality. There is significant concern about their potential impact on disease burden and the effectiveness of current control approaches. Few attempts have been made to increase our understanding of the relationship between urbanization and disease dynamics, although it is generally believed that urban living has contributed to reductions in communicable disease burden in industrialized countries. To investigate this relationship, we carried out spatiotemporal analyses using a 48-year-long dataset of hemorrhagic fever with renal syndrome incidence (HFRS; mainly caused by two serotypes of hantavirus in China: Hantaan virus and Seoul virus) and population movements in an important endemic area of south China during the period 1963–2010. Our findings indicate that epidemics coincide with urbanization, geographic expansion, and migrant movement over time. We found a biphasic inverted U-shaped relationship between HFRS incidence and urbanization, with various endemic turning points associated with economic growth rates in cities. Our results revealed the interrelatedness of urbanization, migration, and hantavirus epidemiology, potentially explaining why urbanizing cities with high economic growth exhibit extended epidemics. Our results also highlight contrasting effects of urbanization on zoonotic disease outbreaks during periods of economic development in China. PMID:29666240

Integrated Framework for an Urban Climate Adaptation Tool

NASA Astrophysics Data System (ADS)

Omitaomu, O.; Parish, E. S.; Nugent, P.; Mei, R.; Sylvester, L.; Ernst, K.; Absar, M.

2015-12-01

Cities have an opportunity to become more resilient to future climate change through investments made in urban infrastructure today. However, most cities lack access to credible high-resolution climate change projection information needed to assess and address potential vulnerabilities from future climate variability. Therefore, we present an integrated framework for developing an urban climate adaptation tool (Urban-CAT). Urban-CAT consists of four modules. Firstly, it provides climate projections at different spatial resolutions for quantifying urban landscape. Secondly, this projected data is combined with socio-economic data using leading and lagging indicators for assessing landscape vulnerability to climate extremes (e.g., urban flooding). Thirdly, a neighborhood scale modeling approach is presented for identifying candidate areas for adaptation strategies (e.g., green infrastructure as an adaptation strategy for urban flooding). Finally, all these capabilities are made available as a web-based tool to support decision-making and communication at the neighborhood and city levels. In this paper, we present some of the methods that drive each of the modules and demo some of the capabilities available to-date using the City of Knoxville in Tennessee as a case study.

Urban landscapes can change virus gene flow and evolution in a fragmentation-sensitive carnivore

USGS Publications Warehouse

Fountain-Jones, Nicholas M.; Craft, Meggan E.; Funk, W. Chris; Kozakiewicz, Chris; Trumbo, Daryl; Boydston, Erin E.; Lyren, Lisa M.; Crooks, Kevin R.; Lee, Justin S.; VandeWoude, Sue; Carver, Scott

2017-01-01

Urban expansion has widespread impacts on wildlife species globally, including the transmission and emergence of infectious diseases. However, there is almost no information about how urban landscapes shape transmission dynamics in wildlife. Using an innovative phylodynamic approach combining host and pathogen molecular data with landscape characteristics and host traits, we untangle the complex factors that drive transmission networks of Feline Immunodeficiency Virus (FIV) in bobcats (Lynx rufus). We found that the urban landscape played a significant role in shaping FIV transmission. Even though bobcats were often trapped within the urban matrix, FIV transmission events were more likely to occur in areas with more natural habitat elements. Urban fragmentation also resulted in lower rates of pathogen evolution, possibly owing to a narrower range of host genotypes in the fragmented area. Combined, our findings show that urban landscapes can have impacts on a pathogen and its evolution in a carnivore living in one of the most fragmented and urban systems in North America. The analytical approach used here can be broadly applied to other host-pathogen systems, including humans.

Utilization of waste heat in trucks for increased fuel economy

NASA Technical Reports Server (NTRS)

Leising, C. J.; Purohit, G. P.; Degrey, S. P.; Finegold, J. G.

1978-01-01

The waste heat utilization concepts include preheating, regeneration, turbocharging, turbocompounding, and Rankine engine compounding. Predictions are based on fuel-air cycle analyses, computer simulation, and engine test data. All options are evaluated in terms of maximum theoretical improvements, but the Diesel and adiabatic Diesel are also compared on the basis of maximum expected improvement and expected improvement over a driving cycle. The study indicates that Diesels should be turbocharged and aftercooled to the maximum possible level. The results reveal that Diesel driving cycle performance can be increased by 20% through increased turbocharging, turbocompounding, and Rankine engine compounding. The Rankine engine compounding provides about three times as much improvement as turbocompounding but also costs about three times as much. Performance for either can be approximately doubled if applied to an adiabatic Diesel.

Urbanization accelerates long-term salinization and alkalinization of fresh water

NASA Astrophysics Data System (ADS)

Kaushal, S.; Duan, S.; Doody, T.; Haq, S.; Smith, R. M.; Newcomer Johnson, T. A.; Delaney Newcomb, K.; Gorman, J. K.; Bowman, N.; Mayer, P. M.; Wood, K. L.; Belt, K.; Stack, W.

2017-12-01

Human dominated land-use increases transport a major ions in streams due to anthropogenic salts and accelerated weathering. We show long-term trends in calcium, magnesium, sodium, alkalinity, and hardness over 50 years in the Baltimore metropolitan region and elsewhere. We also examine how major ion concentrations have increased significantly with impervious surface cover in watersheds across land use. Base cations show strong relationships with acid anions, which illustrates the coupling of major biogeochemical cycles in urban watersheds over time. Longitudinal patterns in major ions can also show increasing trends from headwaters to coastal waters, which suggests coupled biogeochemical cycles over space. We present new results from manipulative experiments and long-term monitoring across different urban regions regarding patterns and processes of salinization and alkalinization. Overall, our work demonstrates that urbanization dramatically increases major ions, ionic strength, and pH over decades from headwaters to coastal waters, which impacts the integrity of aquatic life, infrastructure, drinking water, and coastal ocean alkalinization.

Exploring bicycle route choice behavior with space syntax analysis : final report.

DOT National Transportation Integrated Search

2016-12-31

Cycling provides an environmentally friendly alternative mode of transportation. It improves : urban mobility, livability, and public health, and it also helps in reducing traffic congestion and : emissions. Cycling is gaining popularity both as a re...

Lithographically fabricated silicon microreactor for operando QEXAFS studies in exhaust gas catalysis during simulation of a standard driving cycle

NASA Astrophysics Data System (ADS)

Doronkin, D. E.; Baier, S.; Sheppard, T.; Benzi, F.; Grunwaldt, J.-D.

2016-05-01

Selective catalytic reduction of NOx by ammonia over Cu-ZSM-5 was monitored by operando QEXAFS during simulation of the New European Driving Cycle. The required fast temperature transients were realized using a novel silicon microreactor, enabling simultaneous spectroscopic and kinetic analysis by X-ray absorption spectroscopy (XAS) and mass spectrometry (MS). Periods of high temperature were correlated to an increase in both N2 production and change of coordination of Cu sites. This operando approach using Si microreactors can be applied to other heterogeneous catalytic systems involving fast temperature transients.

Spacecraft-borne long life cryogenic refrigeration: Status and trends

NASA Technical Reports Server (NTRS)

Johnson, A. L.

1983-01-01

The status of cryogenic refrigerator development intended for, or possibly applicable to, long life spacecraft-borne application is reviewed. Based on these efforts, the general development trends are identified. Using currently projected technology needs, the various trends are compared and evaluated. The linear drive, non-contacting bearing Stirling cycle refrigerator concept appears to be the best current approach that will meet the technology projection requirements for spacecraft-borne cryogenic refrigerators. However, a multiply redundant set of lightweight, moderate life, moderate reliability Stirling cycle cryogenic refrigerators using high-speed linear drive and sliding contact bearings may possibly suffice.

Determining the Carrier-Envelope Phase of Intense Few-Cycle Laser Pulses

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

Mackenroth, F.; Di Piazza, A.; Keitel, C. H.

2010-08-06

The electromagnetic radiation emitted by an ultrarelativistic accelerated electron is extremely sensitive to the precise shape of the field driving the electron. We show that the angular distribution of the photons emitted by an electron via multiphoton Compton scattering off an intense (I>10{sup 20} W/cm{sup 2}), few-cycle laser pulse provides a direct way of determining the carrier-envelope phase of the driving laser field. Our calculations take into account exactly the laser field, include relativistic and quantum effects and are in principle applicable to presently available and future foreseen ultrastrong laser facilities.

Cars Gone Wild: The Major Contributor to Unintended Acceleration in Automobiles is Pedal Error

PubMed Central

Schmidt, Richard A.; Young, Douglas E.

2010-01-01

“Unintended-acceleration” automobile accidents typically begin when the driver first enters the car, starts the engine, and intends to press his/her right foot on the brake while shifting from Park to a drive gear (Drive or Reverse). The driver reports an unintended (uncommanded) full-throttle acceleration, coupled with a loss of braking, until the episode ends in a crash. Pedal misapplications – where the right foot contacts the accelerator instead of the brake that was intended – have been linked to these accidents (Schmidt, 1989, 1993) which, in the 1980s, were thought to occur only at the start of a driving cycle (and/or with the car in Park). But, in 1997, we identified over 200 pedal errors as the cause of accidents reported in the North Carolina database; these crashes occurred during the driving cycle (Schmidt et al., 1997), and/or with the vehicle in a gear other than Park. Our present work provides a more thorough analysis of these North Carolina Police Accident Reports from 1979 to 1995. The vast majority of pedal misapplications (over 92%) (a) occurred during the driving cycle, (b) were generally in “unhurried” conditions, and (c) were categorically separate from those events referred to as unintended-acceleration episodes at start-up. These ideas are explanatory for the recent (2009–2010) surge of unintended-acceleration reports, perhaps even suggesting that all of these crashes are caused by pedal errors, and that none of them are based on some vehicle defect(s). PMID:21833265

Life cycle inventory energy consumption and emissions for biodiesel versus petroleum diesel fueled construction vehicles.

PubMed

Pang, Shih-Hao; Frey, H Christopher; Rasdorf, William J

2009-08-15

Substitution of soy-based biodiesel fuels for petroleum diesel will alter life cycle emissions for construction vehicles. A life cycle inventory was used to estimate fuel cycle energy consumption and emissions of selected pollutants and greenhouse gases. Real-world measurements using a portable emission measurement system (PEMS) were made forfive backhoes, four front-end loaders, and six motor graders on both fuels from which fuel consumption and tailpipe emission factors of CO, HC, NO(x), and PM were estimated. Life cycle fossil energy reductions are estimated it 9% for B20 and 42% for B100 versus petroleum diesel based on the current national energy mix. Fuel cycle emissions will contribute a larger share of total life cycle emissions as new engines enter the in-use fleet. The average differences in life cycle emissions for B20 versus diesel are: 3.5% higher for NO(x); 11.8% lower for PM, 1.6% higher for HC, and 4.1% lower for CO. Local urban tailpipe emissions are estimated to be 24% lower for HC, 20% lower for CO, 17% lower for PM, and 0.9% lower for NO(x). Thus, there are environmental trade-offs such as for rural vs urban areas. The key sources of uncertainty in the B20 LCI are vehicle emission factors.

93. DETAIL OF GENERAL ELECTRIC 250HP SYNCHRONOUS MOTOR FROM DRIVE ...

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

93. DETAIL OF GENERAL ELECTRIC 250-HP SYNCHRONOUS MOTOR FROM DRIVE END. MOTOR BADGE PLATE READS 263 AMP, 400 VOLT, FRAME 6274-D #4940649, 250 HORSEPOWER, TYPE TSR, 3 PHASE, 60 CYCLE, SPEED 300 RPM. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

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...

Report of an Urban Education Reform Experiment: Problems and Promises. Section II: Project Evaluation. Supplement to the Final Report of the 5th Cycle Teacher Corps Project.

ERIC Educational Resources Information Center

Rippey, Robert M.

This document recounts the efforts of an urban college of education (the one at the University of Illinois/Chicago Circle) to develop a cooperative program in urban teacher education. It deals with the origin of the project, operational problems encountered, solutions attempted, critical functions of systematic evaluation. Also included are…

Trends in Fatalities From Distracted Driving in the United States, 1999 to 2008

PubMed Central

Stimpson, Jim P.

2010-01-01

Objectives. We examined trends in distracted driving fatalities and their relation to cell phone use and texting volume. Methods. The Fatality Analysis Reporting System (FARS) records data on all road fatalities that occurred on public roads in the United States from 1999 to 2008. We studied trends in distracted driving fatalities, driver and crash characteristics, and trends in cell phone use and texting volume. We used multivariate regression analysis to estimate the relation between state-level distracted driving fatalities and texting volumes. Results. After declining from 1999 to 2005, fatalities from distracted driving increased 28% after 2005, rising from 4572 fatalities to 5870 in 2008. Crashes increasingly involved male drivers driving alone in collisions with roadside obstructions in urban areas. By use of multivariate analyses, we predicted that increasing texting volumes resulted in more than 16 000 additional road fatalities from 2001 to 2007. Conclusions. Distracted driving is a growing public safety hazard. Specifically, the dramatic rise in texting volume since 2005 appeared to be contributing to an alarming rise in distracted driving fatalities. Legislation enacting texting bans should be paired with effective enforcement to deter drivers from using cell phones while driving. PMID:20864709

Trends in fatalities from distracted driving in the United States, 1999 to 2008.

PubMed

Wilson, Fernando A; Stimpson, Jim P

2010-11-01

We examined trends in distracted driving fatalities and their relation to cell phone use and texting volume. The Fatality Analysis Reporting System (FARS) records data on all road fatalities that occurred on public roads in the United States from 1999 to 2008. We studied trends in distracted driving fatalities, driver and crash characteristics, and trends in cell phone use and texting volume. We used multivariate regression analysis to estimate the relation between state-level distracted driving fatalities and texting volumes. After declining from 1999 to 2005, fatalities from distracted driving increased 28% after 2005, rising from 4572 fatalities to 5870 in 2008. Crashes increasingly involved male drivers driving alone in collisions with roadside obstructions in urban areas. By use of multivariate analyses, we predicted that increasing texting volumes resulted in more than 16,000 additional road fatalities from 2001 to 2007. Distracted driving is a growing public safety hazard. Specifically, the dramatic rise in texting volume since 2005 appeared to be contributing to an alarming rise in distracted driving fatalities. Legislation enacting texting bans should be paired with effective enforcement to deter drivers from using cell phones while driving.

Assessing cost-effectiveness of bioretention on stormwater in response to climate change and urbanization for future scenarios

NASA Astrophysics Data System (ADS)

Wang, Mo; Zhang, Dongqing; Adhityan, Appan; Ng, Wun Jern; Dong, Jianwen; Tan, Soon Keat

2016-12-01

Bioretention, as a popular low impact development practice, has become more important to mitigate adverse impacts on urban stormwater. However, there is very limited information regarding ensuring the effectiveness of bioretention response to uncertain future challenges, especially when taking into consideration climate change and urbanization. The main objective of this paper is to identify the cost-effectiveness of bioretention by assessing the hydrology performance under future scenarios modeling. First, the hydrology model was used to obtain peak runoff and TSS loads of bioretention with variable scales under different scenarios, i.e., different Representative Concentration Pathways (RCPs) and Shared Socio-economic reference Pathways (SSPs) for 2-year and 10-year design storms in Singapore. Then, life cycle costing (LCC) and life cycle assessment (LCA) were estimated for bioretention, and the cost-effectiveness was identified under different scenarios. Our finding showed that there were different degree of responses to 2-year and 10-year design storms but the general patterns and insights deduced were similar. The performance of bioretenion was more sensitive to urbanization than that for climate change in the urban catchment. In addition, it was noted that the methodology used in this study was generic and the findings could be useful as reference for other LID practices in response to climate change and urbanization.

Catchment hydrological change from soil degradation: A model study for assessing urbanization on the terrestrial water cycle

NASA Astrophysics Data System (ADS)

Shu, L.; Duffy, C.

2015-12-01

It is commonly held that land cover and land use changes from agriculture and urbanization impact the terrestrial water cycle primarily through changes in the land surface and canopy energy balance. Another, and in some cases more important factor is the role that landuse changes have on soil structure, compaction, and loss of carbon on hydrologic performance. The consequential change on soil properties, such as aggregation of soil particles, reduction of voids, impacts on matrix conductivity and macropore fractions, alter the hydrological processes in a watershed. Macropores promote rapid water and gas movement under wet conditions while the soil matrix preserves the water-holding capacity necessary for plant growth. The physically-based Penn State Integrated Hydrologic Model (PIHM) simulates water movement in soil with Richard's equation using an effective matrix-macropore conductivity. The model is able to capture the preferential flow and soil water storage in vertical and horizontal directions. Soil degradation leads to a reduction of the macropore fraction with dramatic changes in overall hydrologic performance under urban development and agricultural landuse practices. The effects on the terrestrial water cycle in the catchment reduce infiltration, soil water availability, recharge and subsurface baseflow to streams, while increasing heavy surface runoff and erosion. The Lancaster area and surrounding watershed in eastern Pennsylvania, USA is a benchmark watershed comprised of urban (24%), agricultural (58%) and forest lands (18%) respectively. After parameter estimation from national geospatial soils, landuse and historical climate reanalysis, three landuse scenarios were developed. 1) Pre-development forest landuse (<1700 AD), (2) deforestation for agriculture and light urban landuse (1700-1900), (3) urban-suburban development (1900-pres.). The watershed model was used to evaluate hydrologic changes due to landuse change and soil degradation. The effects of macropore reduction and compaction on hydrologic performance were found to be of the same order or greater magnitude than for changes in landuse practices alone. The research, funded by the US EPA, illustrates the complex interaction of landuse and soil changes on the terrestrial water cycle.

The Impact of Urbanization on the Precipitation Component of the Water Cycle: A New Perspective

NASA Technical Reports Server (NTRS)

Shephard, J. Marshal

2002-01-01

It is estimated that by the year 2025, 60% of the world s population will live in cities (UNFP, 1999). As cities continue to grow, urban sprawl (e.g., the expansion of urban surfaces outward into rural surroundings) creates unique problems related to land use, transportation, agriculture, housing, pollution, and development. Urban expansion also has measurable impacts on environmental processes. Urban areas modify boundary layer processes through the creation of an urban heat island (UHI). The literature indicates that the signature of the urban heat island effect may be resolvable in rainfall patterns over and downwind of metropolitan areas. However, a recent U.S. Weather Research Program panel concluded that more observational and modeling research is needed in this area (Dabberdt et al. 2000). NASA and other agencies initiated programs such as the Atlanta Land-use Analysis: Temperature and Air Quality Project (ATLANTA) (Quattrochi et al. 1998) which aimed to identify and understand how urban heat islands impact the environment. However, a comprehensive assessment of the role of urban-induced rainfall in the global water and energy cycle (GWEC) and cycling of freshwater was not a primary focus of these efforts. NASA's Earth Science Enterprise (ESE) seeks to develop a scientific understanding of the Earth system and its response to natural or human-induced changes to enable improved prediction capability for climate, weather, and natural hazards (NASA, 2000). Within this mission, the ESE has three basic thrusts: science research to increase Earth system knowledge; an applications program to transfer science knowledge to practical use in society; and a technology program to enable new, better, and cheaper capabilities for observing the earth. Within this framework, a research program is underway to further address the co-relationship between land cover use and change (e.g. urban development) and its impact on key components of the GWEC (e.g., precipitation). This presentation discusses the feasibility of using the TRMM or GPM satellite to identify precipitation anomalies likely caused by urbanization (Shepherd et al. 2002). Recent results from analyses of TRMM data around several major U.S. cities (e.g. Dallas, Atlanta, Houston) will be discussed. The presentation also summarizes a NASA-funded research effort to investigate the phenomenon of urban-induced precipitation anomalies using TRMM (future GPM) satellite-based remote sensing, an intensive ground observation/validation effort near Atlanta, and coupled atmosphere-land numerical modeling techniques.

Status of Advanced Propulsion Technology in Japan

DOT National Transportation Integrated Search

1982-03-01

This report describes the efforts of the Japanese transit industry, which includes manufacturers and transit operators, in the area of advanced propulsion systems for urban rail vehicles. It presents different chopper system designs, new ac drive dev...

High resolution modeling of a small urban catchment

NASA Astrophysics Data System (ADS)

Skouri-Plakali, Ilektra; Ichiba, Abdellah; Gires, Auguste; Tchiguirinskaia, Ioulia; Schertzer, Daniel

2016-04-01

Flooding is one of the most complex issues that urban environments have to deal with. In France, flooding remains the first natural risk with 72% of decrees state of natural disaster issued between October 1982 and mid-November 2014. Flooding is a result of meteorological extremes that are usually aggravated by the hydrological behavior of urban catchments and human factors. The continuing urbanization process is indeed changing the whole urban water cycle by limiting the infiltration and promoting runoff. Urban environments are very complex systems due to their extreme variability, the interference between human activities and natural processes but also the effect of the ongoing urbanization process that changes the landscape and hardly influences their hydrologic behavior. Moreover, many recent works highlight the need to simulate all urban water processes at their specific temporal and spatial scales. However, considering urban catchments heterogeneity still challenging for urban hydrology, even after advances noticed in term of high-resolution data collection and computational resources. This issue is more to be related to the architecture of urban models being used and how far these models are ready to take into account the extreme variability of urban catchments. In this work, high spatio-temporal resolution modeling is performed for a small and well-equipped urban catchment. The aim of this work is to identify urban modeling needs in terms of spatial and temporal resolution especially for a very small urban area (3.7 ha urban catchment located in the Perreux-sur-Marne city at the southeast of Paris) MultiHydro model was selected to carry out this work, it is a physical based and fully distributed model that interacts four existing modules each of them representing a portion of the water cycle in urban environments. MultiHydro was implemented at 10m, 5m and 2m resolution. Simulations were performed at different spatio-temporal resolutions and analyzed with respect to real flow measurements. First Results coming out show improvements obtained in terms of the model performance at high spatio-temporal resolution.

Fleet DNA Phase 1 Refinement & Phase 2 Implementation; NREL (National Renewable Energy Laboratory)

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

Kelly, Kenneth; Duran, Adam

2015-06-11

Fleet DNA acts as a secure data warehouse for medium- and heavy-duty vehicle data. It demonstrates that vehicle drive cycle data can be collected and stored for large-scale analysis and modeling applications. The data serve as a real-world data source for model development and validation. Storage of the results of past/present/future data collection efforts improves analysis efficiency through pooling of shared data and provides the opportunity for 'big data' type analyses. Fleet DNA shows it is possible to develop a common database structure that can store/analyze/report on data sourced from multiple parties, each with unique data formats/types. Data filtration andmore » normalization algorithms developed for the project allow for a wide range of data types and inputs, expanding the project’s potential. Fleet DNA demonstrates the power of integrating Big Data with existing and future tools and analyses: it provides an enhanced understanding and education of users, users can explore greenhouse gases and economic opportunities via AFLEET and ADOPT modeling, drive cycles can be characterized and visualized using DRIVE, high-level vehicle modeling can be performed using real-world drive cycles via FASTSim, and data reporting through Fleet DNA Phase 1 and 2 websites provides external users access to analysis results and gives the opportunity to explore on their own.« less

Cognitive evaluation by tasks in a virtual reality environment in multiple sclerosis.

PubMed

Lamargue-Hamel, Delphine; Deloire, Mathilde; Saubusse, Aurore; Ruet, Aurélie; Taillard, Jacques; Philip, Pierre; Brochet, Bruno

2015-12-15

The assessment of cognitive impairment in multiple sclerosis (MS) requires large neuropsychological batteries that assess numerous domains. The relevance of these assessments to daily cognitive functioning is not well established. Cognitive ecological evaluation has not been frequently studied in MS. The aim of this study was to determine the interest of cognitive evaluation in a virtual reality environment in a sample of persons with MS with cognitive deficits. Thirty persons with MS with at least moderate cognitive impairment were assessed with two ecological evaluations, an in-house developed task in a virtual reality environment (Urban DailyCog®) and a divided attention task in a driving simulator. Classical neuropsychological testing was also used. Fifty-two percent of the persons with MS failed the driving simulator task and 80% failed the Urban DailyCog®. Virtual reality assessments are promising in identifying cognitive impairment in MS. Copyright © 2015 Elsevier B.V. All rights reserved.

Green roof impact on the hydrological cycle components

NASA Astrophysics Data System (ADS)

Lamera, Carlotta; Rulli, Maria Cristina; Becciu, Gianfranco; Rosso, Renzo

2013-04-01

In the last decades the importance of storm water management in urban areas has increased considerably, due to both urbanization extension and to a greater concern for environment pollution. Traditional storm water control practices, based on the "all to the sewer" attitude, rely on conveyance to route storm water runoff from urban impervious surfaces towards the nearby natural water bodies. In recent years, infiltration facilities are receiving an increasing attention, due to their particular efficiency in restoring a balance in hydrological cycle quite equal to quite pre-urbanization condition. In particular, such techniques are designed to capture, temporarily retain and infiltrate storm water, promote evapotranspiration and harvest water at the source, encouraging in general evaporation, evapotranspiration, groundwater recharge and the re-use of storm water. Green roofs are emerging as an increasingly popular Sustainable Urban Drainage Systems (SUDS) technique for urban storm water management. Indeed, they are able to operate hydrologic control over storm water runoff: they allow a significant reduction of peak flows and runoff volumes collected by drainage system, with a consequent reduction of flooding events and pollution masses discharges by CSO. Furthermore green roofs have a positive influence on the microclimate in urban areas by helping in lower urban air temperatures and mitigate the heat island effect. Last but not least, they have the advantage of improving the thermal insulation of buildings, with significant energy savings. A detailed analysis of the hydrological dynamics, connected both with the characteristics of the climatic context and with the green roof technical design, is essential in order to obtain a full characterization of the hydrologic behavior of a green roof system and its effects on the urban water cycle components. The purpose of this paper is to analysis the hydrological effects and urban benefits of the vegetation cover of a building by installing green roofs and, thus, providing a conversion of rooftops in pervious areas; the objective is modeling hydrological fluxes (interception, evapotranspiration, soil water fluxes in the surface and hypodermic components) in relation to climate forcing, basic technology components and geometric characteristics of green roof systems (thickness of the stratigraphy, soil layers and materials, vegetation typology and density). The sensitivity analysis of hydrological processes at different hydrological, climatic and geometric parameters has allowed to draw some general guidelines useful in the design and construction of this type of drainage systems.

Evapotranspiration and surface energy balance across an agricultural-urban landscape gradient in Southern California, USA.

NASA Astrophysics Data System (ADS)

Shiflett, S. A.; Anderson, R. G.; Jenerette, D.

2014-12-01

Urbanization substantially affects energy, surface and air temperature, and hydrology due to extensive modifications in land surface properties such as vegetation, albedo, thermal capacity and soil moisture. The magnitude and direction of these alterations depends heavily on the type of urbanization that occurs. We investigated energy balance variation in a local network of agricultural and urban ecosystems using the eddy covariance method to better understand how vegetation fraction and degree of urbanization affects energy exchanges between the land surface and the atmosphere. We deployed eddy flux systems within a well-irrigated, agricultural citrus orchard, a moderately developed urban zone with a substantial amount of local vegetative cover, and an intensely developed urban zone with minimal vegetative cover and increased impervious surfaces relative to the other two sites. Latent energy (LE) fluxes in the agricultural area ranged from 7.9 ± 1.4 W m-2 (nighttime) to 168.7 ± 6.2 W m-2 (daytime) compared to 10.2 ± 3.5 W m-2 and 40.6 ± 4.1 W m-2, respectively, for the moderately developed urban area. Sensible energy (H) fluxes ranged from -9.1 ± 1.0 W m-2 (nighttime) to 119 ± 7.0 W m-2 (daytime) in the agricultural area compared to 9.6 ± 2.6 W m-2 and 134 ± 6.0 W m-2, respectively, for the moderately developed urban zone. Daytime LE is reduced with increasing urbanization; however, daily cycles of LE are less recognizable in urban areas compared to distinct daily cycles obtained above a mature citrus crop. In contrast, both daytime and nighttime H increases with increasing degree of urbanization. Reduction in vegetation and increases in impervious surfaces along an urbanization gradient leads to alterations in energy balance, which are associated with microclimate and water use changes.

Associations of street layout with walking and sedentary behaviors in an urban and a rural area of Japan.

PubMed

Koohsari, Mohammad Javad; Sugiyama, Takemi; Shibata, Ai; Ishii, Kaori; Liao, Yung; Hanibuchi, Tomoya; Owen, Neville; Oka, Koichiro

2017-05-01

We examined whether street layout -a key urban design element- is associated with walking and sedentary behaviors in the context of a non-Western country; and, whether such associations differ between an urban and a rural area. In 2011, 1076 middle-to-older aged adults living in an urban and a rural area of Japan reported their walking and sedentary (sitting) behaviors. Two objective measures of street layout (intersection density and street integration) were calculated. Participants exposed to more-connected street layouts were more likely to walk for commuting and for errands, to meet physical activity recommendations through walking for commuting, and less likely to drive. These relationships differed between the urban and the rural area. This shows that previous findings from Western countries on associations of street connectivity with travel behaviors may also be applicable to Japan. Copyright © 2017 Elsevier Ltd. All rights reserved.

Driving in traffic: short-range sensing for urban collision avoidance

NASA Astrophysics Data System (ADS)

Thorpe, Chuck E.; Duggins, David F.; Gowdy, Jay W.; MacLaughlin, Rob; Mertz, Christoph; Siegel, Mel; Suppe, Arne; Wang, Chieh-Chih; Yata, Teruko

2002-07-01

Intelligent vehicles are beginning to appear on the market, but so far their sensing and warning functions only work on the open road. Functions such as runoff-road warning or adaptive cruise control are designed for the uncluttered environments of open highways. We are working on the much more difficult problem of sensing and driver interfaces for driving in urban areas. We need to sense cars and pedestrians and curbs and fire plugs and bicycles and lamp posts; we need to predict the paths of our own vehicle and of other moving objects; and we need to decide when to issue alerts or warnings to both the driver of our own vehicle and (potentially) to nearby pedestrians. No single sensor is currently able to detect and track all relevant objects. We are working with radar, ladar, stereo vision, and a novel light-stripe range sensor. We have installed a subset of these sensors on a city bus, driving through the streets of Pittsburgh on its normal runs. We are using different kinds of data fusion for different subsets of sensors, plus a coordinating framework for mapping objects at an abstract level.

Driving forces behind the Chinese public's demand for improved environmental safety.

PubMed

Wen, Ting; Wang, Jigan; Ma, Zongwei; Bi, Jun

2017-12-15

Over the past decades, the public demand for improved environmental safety keeps increasing in China. This study aims to assess the driving forces behind the increasing public demand for improved environmental safety using a provincial and multi-year (1995, 2000, 2005, 2010, and 2014) panel data and the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model. The potential driving forces investigated included population size, income levels, degrees of urbanization, and educational levels. Results show that population size and educational level are positively (P<0.01) associated with public demand for improved environmental safety. No significant impact on demand was found due to the degree of urbanization. For the impact due to income level, an inverted U-shaped curve effect with the turning point of ~140,000 CNY GDP per capita is indicated. Since per capita GDP of 2015 in China was approximately 50,000 CNY and far from the turning point, the public demand for improved environmental safety will continue rising in the near future. To meet the increasing public demand for improved environmental safety, proactive and risk prevention based environmental management systems coupled with effective environmental risk communication should be established. Copyright © 2017 Elsevier B.V. All rights reserved.

EVOLUTION OF THE NOCTURNAL INVERSION LAYER AT AN URBAN AND NONURBAN LOCATION

EPA Science Inventory

The evolutionary cycle of the nocturnal radiation inversion layer from formation until dissipation under fair weather conditions was investigated by time-series analyses of observations of inversion base and top heights, and inversion strength at an urban and a nonurban site in S...

A Century of the Evolution of the Urban Area in Shenyang, China

PubMed Central

Liu, Miao; Xu, Yanyan; Hu, Yuanman; Li, Chunlin; Sun, Fengyun; Chen, Tan

2014-01-01

Analyzing spatiotemporal characteristics of the historical urbanization process is essential in understanding the dynamics of urbanization and scientifically planned urban development. Based on historical urban area maps and remote sensing images, this study examined the urban expansion of Shenyang from 1910 to 2010 using area statistics, typology identification, and landscape metrics approaches. The population and gross domestic product were analyzed as driving factors. The results showed that the urban area of Shenyang increased 43.39-fold during the study period and that the growth rate has accelerated since the 1980s. Three urban growth types were distinguished: infilling, edge-expansion, and spontaneous growth. Edge-expansion was the primary growth type. Infilling growth became the main growth type in the periods 1946–70, 1988–97, and 2004–10. Spontaneous growth was concentrated in the period of 1997 to 2000. The results of landscape metrics indicate that the urban landscape of Shenyang originally was highly aggregated, but has become increasingly fragmented. The urban fringe area was the traditional hot zone of urbanization. Shenyang was mainly located north of the Hun River before 1980; however, the south side of the river has been the hot zone of urbanization since the 1980s. The increase of urban area strongly correlated with the growth of GDP and population. Over a long time scale, the urbanization process has been affected by major historical events. PMID:24893167

WaLA, a versatile model for the life cycle assessment of urban water systems: Formalism and framework for a modular approach.

PubMed

Loubet, Philippe; Roux, Philippe; Bellon-Maurel, Véronique

2016-01-01

The emphasis on the sustainable urban water management has increased over the last decades. In this context decision makers need tools to measure and improve the environmental performance of urban water systems (UWS) and their related scenarios. In this paper, we propose a versatile model, named WaLA (Water system Life cycle Assessment), which reduces the complexity of the UWS while ensuring a good representation of water issues and fulfilling life cycle assessment (LCA) requirements. Indeed, LCAs require building UWS models, which can be tedious if several scenarios are to be compared. The WaLA model is based on a framework that uses a "generic component" representing alternately water technology units and water users, with their associated water flows, and the associated impacts due to water deprivation, emissions, operation and infrastructure. UWS scenarios can be built by inter-operating and connecting the technologies and users components in a modular and integrated way. The model calculates life cycle impacts at a monthly temporal resolution for a set of services provided to users, as defined by the scenario. It also provides the ratio of impacts to amount of services provided and useful information for UWS diagnosis or comparison of different scenarios. The model is implemented in a Matlab/Simulink interface thanks to object-oriented programming. The applicability of the model is demonstrated using a virtual case study based on available life cycle inventory data. Copyright © 2015 Elsevier Ltd. All rights reserved.

Medium Truck Duty Cycle Data from Real-World Driving Environments: Final Report

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

Lascurain, Mary Beth; Franzese, Oscar; Capps, Gary J

2012-11-01

Since the early part of the 20th century, the US trucking industry has provided a safe and economical means of moving commodities across the country. At present, nearly 80% of US domestic freight movement involves the use of trucks. The US Department of Energy (DOE) is spearheading a number of research efforts to improve heavy vehicle fuel efficiencies. This includes research in engine technologies (including hybrid and fuel cell technologies), lightweight materials, advanced fuels, and parasitic loss reductions. In addition, DOE is developing advanced tools and models to support heavy vehicle research and is leading the 21st Century Truck Partnershipmore » and the SuperTruck development effort. Both of these efforts have the common goal of decreasing the fuel consumption of heavy vehicles. In the case of SuperTruck, a goal of improving the overall freight efficiency of a combination tractor-trailer has been established. This Medium Truck Duty Cycle (MTDC) project is a critical element in DOE s vision for improved heavy vehicle energy efficiency; it is unique in that there is no other existing national database of characteristic duty cycles for medium trucks based on collecting data from Class 6 and 7 vehicles. It involves the collection of real-world data on medium trucks for various situational characteristics (e.g., rural/urban, freeway/arterial, congested/free-flowing, good/bad weather) and looks at the unique nature of medium trucks drive cycles (stop-and-go delivery, power takeoff, idle time, short-radius trips). This research provides a rich source of data that can contribute to the development of new tools for FE and modeling, provide DOE a sound basis upon which to make technology investment decisions, and provide a national archive of real-world-based medium-truck operational data to support energy efficiency research. The MTDC project involved a two-part field operational test (FOT). For the Part-1 FOT, three vehicles each from two vocations (urban transit and dry-box delivery) were instrumented for the collection of one year of operational data. The Part-2 FOT involved the towing and recovery and utility vocations for a second year of data collection. The vehicles that participated in the MTDC project did so through gratis partnerships in return for early access to the results of this study. Partnerships such as these are critical to FOTs in which real-world data is being collected. In Part 1 of the project, Oak Ridge National Laboratory (ORNL) established partnerships with the H.T. Hackney Company (HTH), one of the largest wholesale distributors in the country, distributing products to 21 states; and with Knoxville Area Transit (KAT), the city of Knoxville s transit system, which operates across Knoxville and parts of Knox County. These partnerships and agreements provided ORNL access to three Class-7 day-cab tractors that regularly haul 28 ft pup trailers (HTH) and three Class-7 buses for the collection of duty cycle data. In addition, ORNL collaborated with the Federal Motor Carrier Safety Administration (FMCSA) to determine if there were possible synergies between this duty cycle data collection effort and FMCSA s need to learn more about the operation and duty cycles of medium trucks. FMCSA s primary interest was in collecting safety data relative to the driver, carrier, and vehicle. In Part 2 of the project, ORNL partnered with the Knoxville Utilities Board, which made available three Class-8 trucks. Fountain City Wrecker Service was also a Part 2 partner, providing three Class-6 rollback trucks. In order to collect the duty cycle and safety-related data, ORNL developed a data acquisition system (DAS) that was placed on each test vehicle. Each signal recorded in this FOT was collected by means of one of the instruments incorporated into each DAS. Other signals were obtained directly from the vehicle s J1939 and J1708 data buses. A VBOX II Lite collected information available from a global positioning system (GPS), including speed, acceleration, and spatial location information at a rate of 5 Hz for the Part 1 FOT. For the Part 2 FOT, this information was obtained from DAS-based GPS instrumentation. The Air-Weigh LoadMaxx, a self-weighing system that determines the vehicle s gross weight by means of pressure transducers, was used to collect vehicle payload information for the combination, urban transit, and towing and recovery vehicles. A cellular modem, the Raven X EVDO V4221, facilitated the communication between the eDAQ-lite (the data collection engine of the system) and the user. The modem functioned as a wireless gateway, allowing data retrievals and system checks to be performed remotely. Also, in partnership with FMCSA, two additional safety sensors were installed on the combination vehicles: the MGM e-Stroke brake monitoring system and the Tire SafeGuard tire pressure monitoring system. All of these sensors posted data to the J1939 data bus, enabling the signals to be read withou...« less

Influence of bio-fuels on passenger car vehicle emissions

NASA Astrophysics Data System (ADS)

Petrea, M.; Kapernaum, M.; Wahl, C.

2009-04-01

In order to reduce the emissions of air pollutants, vehicles design and fuel formulation have changed. Ultra clean vehicle technologies started to be used in increased number. As a result, the emissions composition is expected to change as well. The use of new technologies and new fuels require new emissions tests especially for non-regulated compounds. The interest in using bio fuels as alternative fuels for petroleum-based ones has increased constantly in the last years. The advantages of the bio fuels usage is given by their similar proprieties, characteristics of renew ability, biodegradability and potential beneficial effects on the exhaust emission. The study involved measurements on a roller test facility of a reference passenger car representing new technologies (emission standards, injection system). The vehicle operated by use of reference gasoline and reference gasoline blended (10 and 20%) with bio-ethanol (EtOH). The measurements used different driving cycles: ARTEMIS cycle, real world driving cycle, NEDC cycle, the standard European driving cycle and additionally, a driving cycle consisting in Idle, 30, 50, 90 km/h. The sampling positions were before and after the catalyst and in the exhaust pipe. The detailed speciation of NMVOC' (non methane volatile organic compounds) was completed by use of active carbon tubes, DNPH (2,4-dinitrophenylhydrazine) tubes and cold traps. The particles were monitored by use of an on-line EEPS (Engine Exhaust Particle Sizer). CO2, NO, NO2 and NOX (NO +NO2) were continuously monitored by use of an on- line FTIR (Fourier transform infrared spectroscopy)- MEXA system. The investigations reveal that among the carbonylic compounds 15 oxygenated species were found in engine out exhaust and only 3 in tailpipe emissions, namely formaldehyde, acetaldehyde and acroleine. These are of great interest due to their impacts on human health. The hydrocarbons emissions decrease by increased of EtOH content. New compounds were observed. The nitro-compounds found in the after engine position by increased EtOH were no more found in the exhaust gas. The results show that total particle concentration, mass and diameter decreased substantially after catalyst and filter by increased ethanol blend.

Modulation of corticospinal input to the legs by arm and leg cycling in people with incomplete spinal cord injury.

PubMed

Zhou, R; Alvarado, L; Kim, S; Chong, S L; Mushahwar, V K

2017-10-01

The spinal cervico-lumbar interaction during rhythmic movements in humans has recently been studied; however, the role of arm movements in modulating the corticospinal drive to the legs is not well understood. The goals of this study were to investigate the effect of active rhythmic arm movements on the corticospinal drive to the legs ( study 1 ) and assess the effect of simultaneous arm and leg training on the corticospinal pathway after incomplete spinal cord injury (iSCI) ( study 2). In study 1 , neurologically intact (NI) participants or participants with iSCI performed combinations of stationary and rhythmic cycling of the arms and legs while motor evoked potentials (MEPs) were recorded from the vastus lateralis (VL) muscle. In the NI group, arm cycling alone could facilitate the VL MEP amplitude, suggesting that dynamic arm movements strongly modulate the corticospinal pathway to the legs. No significant difference in VL MEP between conditions was found in participants with iSCI. In study 2 , participants with iSCI underwent 12 wk of electrical stimulation-assisted cycling training: one group performed simultaneous arm and leg (A&L) cycling and the other legs-only cycling. MEPs in the tibialis anterior (TA) muscle were compared before and after training. After training, only the A&L group had a significantly larger TA MEP, suggesting increased excitability in the corticospinal pathway. The findings demonstrate the importance of arm movements in modulating the corticospinal drive to the legs and suggest that active engagement of the arms in lower limb rehabilitation may produce better neural regulation and restoration of function. NEW & NOTEWORTHY This study aimed to demonstrate the importance of arm movements in modulating the corticospinal drive to the legs. It provides direct evidence in humans that active movement of the arms could facilitate corticospinal transmission to the legs and, for the first time, shows that facilitation is absent after spinal cord injury. Active engagement of the arms in lower limb rehabilitation increased the excitability of the corticospinal pathway and may produce more effective improvement in leg function. Copyright © 2017 the American Physiological Society.

Ultrasonic Sensors in Urban Traffic Driving-Aid Systems

PubMed Central

Alonso, Luciano; Milanés, Vicente; Torre-Ferrero, Carlos; Godoy, Jorge; Oria, Juan P.; de Pedro, Teresa

2011-01-01

Currently, vehicles are often equipped with active safety systems to reduce the risk of accidents, most of which occur in urban environments. The most prominent include Antilock Braking Systems (ABS), Traction Control and Stability Control. All these systems use different kinds of sensors to constantly monitor the conditions of the vehicle, and act in an emergency. In this paper the use of ultrasonic sensors in active safety systems for urban traffic is proposed, and the advantages and disadvantages when compared to other sensors are discussed. Adaptive Cruise Control (ACC) for urban traffic based on ultrasounds is presented as an application example. The proposed system has been implemented in a fully-automated prototype vehicle and has been tested under real traffic conditions. The results confirm the good performance of ultrasonic sensors in these systems. PMID:22346596

Ultrasonic sensors in urban traffic driving-aid systems.

PubMed

Alonso, Luciano; Milanés, Vicente; Torre-Ferrero, Carlos; Godoy, Jorge; Oria, Juan P; de Pedro, Teresa

2011-01-01

Currently, vehicles are often equipped with active safety systems to reduce the risk of accidents, most of which occur in urban environments. The most prominent include Antilock Braking Systems (ABS), Traction Control and Stability Control. All these systems use different kinds of sensors to constantly monitor the conditions of the vehicle, and act in an emergency. In this paper the use of ultrasonic sensors in active safety systems for urban traffic is proposed, and the advantages and disadvantages when compared to other sensors are discussed. Adaptive Cruise Control (ACC) for urban traffic based on ultrasounds is presented as an application example. The proposed system has been implemented in a fully-automated prototype vehicle and has been tested under real traffic conditions. The results confirm the good performance of ultrasonic sensors in these systems.

Modeling the reaction kinetics of a hydrogen generator onboard a fuel cell -- Electric hybrid motorcycle

NASA Astrophysics Data System (ADS)

Ganesh, Karthik

Owing to the perceived decline of the fossil fuel reserves in the world and environmental issues like pollution, conventional fuels may be replaced by cleaner alternative fuels. The potential of hydrogen as a fuel in vehicular applications is being explored. Hydrogen as an energy carrier potentially finds applications in internal combustion engines and fuel cells because it is considered a clean fuel and has high specific energy. However, at 6 to 8 per kilogram, not only is hydrogen produced from conventional methods like steam reforming expensive, but also there are storage and handling issues, safety concerns and lack of hydrogen refilling stations across the country. The purpose of this research is to suggest a cheap and viable system that generates hydrogen on demand through a chemical reaction between an aluminum-water slurry and an aqueous sodium hydroxide solution to power a 2 kW fuel cell on a fuel cell hybrid motorcycle. This reaction is essentially an aluminum-water reaction where sodium hydroxide acts as a reaction promoter or catalyst. The Horizon 2000 fuel cell used for this purpose has a maximum hydrogen intake rate of 28 lpm. The study focuses on studying the exothermic reaction between the reactants and proposes a rate law that best describes the rate of generation of hydrogen in connection to the surface area of aluminum available for the certain reaction and the concentration of the sodium hydroxide solution. Further, the proposed rate law is used in the simulation model of the chemical reactor onboard the hybrid motorcycle to determine the hydrogen flow rate to the fuel cell with time. Based on the simulated rate of production of hydrogen from the chemical system, its feasibility of use on different drive cycles is analyzed. The rate of production of hydrogen with a higher concentration of sodium hydroxide and smaller aluminum powder size was found to enable the installation of the chemical reactor on urban cycles with frequent stops and starts. However, by extrapolating the necessary rate of concentration of sodium hydroxide required to produce hydrogen rates that would enable use of the system on highway drive cycles, it was deemed unsafe due to the caustic nature of the solution used.

Temporal scaling behavior of forest and urban fires

NASA Astrophysics Data System (ADS)

Wang, J.; Song, W.; Zheng, H.; Telesca, L.

2009-04-01

It has been found that many natural systems are characterized by scaling behavior. In such systems natural factors dominate the event dynamics. Forest fires in different countries have been found to exhibit frequency-size power law over many orders of magnitude and with similar value of parameters. But in countries with high population density such as China and Japan, more than 95% of the forest fire disasters are caused by human activities. Furthermore, with the development of society, the wildland-urban interface (WUI) area is becoming more and more populated, and the forest fire is much connected with urban fire. Therefore exploring the scaling behavior of fires dominated by human-related factors is very challenging. The present paper explores the temporal scaling behavior of forest fires and urban fires in Japan with mathematical methods. Two factors, Allan factor (AF) and Fano factor (FF) are used to investigate time-scaling of fire systems. It is found that the FF for both forest fires and urban fires increases linearly in log-log scales, and this indicates that it behaves as a power-law for all the investigated timescales. From the AF plot a 7 days cycle is found, which indicates a weekly cycle. This may be caused by human activities which has a weekly periodicity because on weekends people usually have more outdoor activities, which may cause more hidden trouble of fire disasters. Our findings point out that although the human factors are the main cause, both the forest fires and urban fires exhibit time-scaling behavior. At the same time, the scaling exponents for urban fires are larger than forest fires, signifying a more intense clustering. The reason may be that fires are affected not only by weather condition, but also by human activities, which play a more important role for urban fires than forest fires and have a power law distribution and scaling behavior. Then some work is done to the relative humidity. Similar distribution law characterizes the relative humidity. The AF plot and FF plot of relative humidity validate the existence of a strong link between weather and fires, and it is very likely that the daily humidity cycle determines the daily fire periodicity.

By land or by stream? contribution of constrained dispersal by adult caddisflies to diversity loss from urban headwaters

EPA Science Inventory

The adult stage of streams insects is responsible for important life-cycle processes such as dispersal and reproduction, yet interactions of adult stream insects with terrestrial landscapes are rarely studied. This trend is especially problematic in urbanized landscapes where th...

75 FR 18873 - Notice of Proposed Information Collection: Youthbuild Program

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-13

.... The Youthbuild grant life cycle is approximately 30 months with approximately 86 currently active... DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT [Docket No. FR-5377-N-01] Notice of Proposed... be sent to: Robert Duncan, Department of Housing Urban and Development, 451 7th Street, SW., Room...

Freight Impacts on Small Urban and Rural Areas

DOT National Transportation Integrated Search

2015-10-01

Freight mobility is critical for economic activity and vitality of a region. Freight system performance has also a driving influence on the quality of life in communities that experience freight traffic. Freight movement that results in high levels o...

[Prediction and simulation of urban area expansion in Pearl River Delta Region under the RCPs climate scenarios].

PubMed

Jiang, Oun-ou; Deng, Xiang-zheng; Ke, Xin-li; Zhao, Chun-hong; Zhang, Wei

2014-12-01

The sizes and number of cities in China are increasing rapidly and complicated changes of urban land use system have occurred as the social economy develops rapidly. This study took the urban agglomeration of Pearl River Delta Region as the study area to explore the driving mechanism of dynamic changes of urban area in the urbanization process under the joint influence of natural environment and social economic conditions. Then the CA (cellular automata) model was used to predict and simulate the urban area changes until 2030 under the designed scenarios of planning and RCPs (representative concentration pathways). The results indicated that urbanization was mainly driven by the non-agricultural population growth and social-economic development, and the transportation had played a fundamental role in the whole process, while the areas with high elevation or steep slope restricted the urbanization. Besides, the urban area would keep an expanding trend regardless of the scenarios, however, the expanding speed would slow down with different inflection points under different scenarios. The urban expansion speed increased in the sequence of the planning scenario, MESSAGE scenario and AIM scenario, and that under the MESSAGE climate scenario was more consistent with the current urban development trend. In addition, the urban expansion would mainly concentrate in regions with the relatively high urbanization level, e.g., Guangzhou, Dongguan, Foshan, Shenzhen, Zhanjiang and Chaoshan.

Understanding the health impacts of urbanization in China: A living laboratory for urban biogeochemistry research

NASA Astrophysics Data System (ADS)

Zhu, Y. G.

2015-12-01

China has the largest population in the world, and by 2011, more than 50% of its population are now living in cities. This ongoing societal change has profound impacts on environmental quality and population health. In addition to intensive discharges of waste, urbanization is not only changing the land use and land cover, but also inducing fundamental changes in biogeochemical processes. Unlike biogeochemistry in non-urban environment, the biological component of urban biogeochemistry is dominated by direct human activities, such as air pollution derived from transport, wastewater treatment, garbage disposal and increase in impervious surface etc. Managing urban biogeochemistry will include source control over waste discharge, eco-infrastructure (such as green space and eco-drainage), resource recovery from urban waste stream, and integration with peri-urban ecosystem, particularly with food production system. The overall goal of managing urban biogeochemistry is for human health and wellbeing, which is a global challenge. In this paper, the current status of urban biogeochemistry research in China will be briefly reviewed, and then it will focus on nutrient recycling and waste management, as these are the major driving forces of environmental quality changes in urban areas. This paper will take a holistic view on waste management, covering urban metabolism analysis, technological innovation and integration for resource recovery from urban waste stream, and risk management related to waste recycling and recovery.

Transmission control unit drive based on the AUTOSAR standard

NASA Astrophysics Data System (ADS)

Guo, Xiucai; Qin, Zhen

2018-03-01

It is a trend of automotive electronics industry in the future that automotive electronics embedded system development based on the AUTOSAR standard. AUTOSAR automotive architecture standard has proposed the transmission control unit (TCU) development architecture and designed its interfaces and configurations in detail. This essay has discussed that how to drive the TCU based on AUTOSAR standard architecture. The results show that driving the TCU with the AUTOSAR system improves reliability and shortens development cycles.

Vehicle Real Driving Emissions of Nitrogen Oxides in an Urban Area from a large Vehicle Fleet

NASA Astrophysics Data System (ADS)

Pöhler, Denis; Horbanski, Martin; Oesterle, Tobias; Adler, Tim; Reh, Miriam; Tirpitz, Lukas; Kanatschnig, Florian; Lampel, Joahnnes; Platt, Ulrich

2016-04-01

Nitrogen Oxide (NOx=NO +NO2) emissions by road vehicles are the major contributor for poor air quality in urban areas. High NOx concentrations, and especially NO2, are typically the most problematic pollution in cities. However, emissions vary significantly depending on the type of vehicle, its engine, the age, condition of the vehicle, driving properties, modifications and many more. Even if official NOx emission data of the manufacturer exist, they are only valid for new vehicles and the current vehicle emission scandal shows clearly that these data are often wrong. Thus, real driving emissions (RDE) of the current vehicle fleet is required. With such data the contribution of individual vehicles to the NO2 and NOx levels in urban areas can be estimated. Significant reduction of NOx concentrations can be achieved by identifying the strong emitting vehicles and excluding, replace or modify them. We developed a precise and fast ICAD (Iterative CAvity DOAS) NO2 instrument which can measure the concentration within the emission plume of vehicles under real driving conditions. The sampling was performed with an inlet at the front of a car which was following the investigated vehicles. The instrument measure NO2 and additionally CO2 with a time resolution of 2 seconds. With the observed NO2 values already strong emitters can easily be identified. With the use of known CO2 emissions, more reliable emissions for NO2 can be calculated for each vehicle. Currently the system is expanded with a NOx channel to derive the total nitrogen oxide emissions. The system was successfully applied in several studies over the last two years to investigate NO2 RDE. More than thousand vehicles were investigated. We observed that several vehicles from various brands show much higher emissions than allowed (more than a factor of 5). Highest emissions correlate for trucks and busses typically to older vehicles, what is not the case for cars. A large variability between different cars was found which could often make up a factor of 10 or more. Often new Diesel cars are one of the strongest emitters, which agree well with other findings. However, older busses and trucks feature regularly the highest emissions, but also here strong variability between different vehicle types with different exhaust treatment and modification is observed. This is especially a problem with busses from the public transport which significantly contribute to urban air pollution. Identifying first the strongest emitting busses, which should be replaced first, can help to faster improve urban air quality. New busses and trucks, beside from few exceptions, show surprisingly relatively low emissions. The exceptions indicate potentially broken NOx exhaust treatment. All these findings show that regular RDE are necessary for the whole vehicle fleet to identify strongest NOx emitters and develop strategies to reduce their emissions. They also allow to provide more accurate model calculations on total emissions in urban areas.

Modeling the dynamics of urban growth using multinomial logistic regression: a case study of Jiayu County, Hubei Province, China

NASA Astrophysics Data System (ADS)

Nong, Yu; Du, Qingyun; Wang, Kun; Miao, Lei; Zhang, Weiwei

2008-10-01

Urban growth modeling, one of the most important aspects of land use and land cover change study, has attracted substantial attention because it helps to comprehend the mechanisms of land use change thus helps relevant policies made. This study applied multinomial logistic regression to model urban growth in the Jiayu county of Hubei province, China to discover the relationship between urban growth and the driving forces of which biophysical and social-economic factors are selected as independent variables. This type of regression is similar to binary logistic regression, but it is more general because the dependent variable is not restricted to two categories, as those previous studies did. The multinomial one can simulate the process of multiple land use competition between urban land, bare land, cultivated land and orchard land. Taking the land use type of Urban as reference category, parameters could be estimated with odds ratio. A probability map is generated from the model to predict where urban growth will occur as a result of the computation.

Upgraded automotive gas turbine engine design and development program, volume 2

NASA Technical Reports Server (NTRS)

Wagner, C. E. (Editor); Pampreen, R. C. (Editor)

1979-01-01

Results are presented for the design and development of an upgraded engine. The design incorporated technology advancements which resulted from development testing on the Baseline Engine. The final engine performance with all retro-fitted components from the development program showed a value of 91 HP at design speed in contrast to the design value of 104 HP. The design speed SFC was 0.53 versus the goal value of 0.44. The miss in power was primarily due to missing the efficiency targets of small size turbomachinery. Most of the SFC deficit was attributed to missed goals in the heat recovery system relative to regenerator effectiveness and expected values of heat loss. Vehicular fuel consumption, as measured on a chassis dynamometer, for a vehicle inertia weight of 3500 lbs., was 15 MPG for combined urban and highway driving cycles. The baseline engine achieved 8 MPG with a 4500 lb. vehicle. Even though the goal of 18.3 MPG was not achieved with the upgraded engine, there was an improvement in fuel economy of 46% over the baseline engine, for comparable vehicle inertia weight.