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1.
Facilitated by fuel economy, climate legislation and government policy, sales of light-duty plug-in hybrid and battery electric vehicles are rapidly increasing during the last decade. But their energy and emissions impact have not been fully investigated, particularly accounting for energy and emissions during electricity generation. In this study, we conducted in-use energy consumption and emissions measurements of a plug-in and a battery electric vehicle under real-world city and highway driving conditions. We further compare them with energy consumption and emissions from counterpart conventional vehicles under the same driving conditions, to exclude benefits due to different vehicle specifications. Our results show that both the plug-in hybrid and battery electric vehicles can achieve about 50% energy benefits compared with their counterpart conventional vehicles, mainly through capturing regenerative energy. But when vehicles are tested in high-speed or high-acceleration driving conditions, the distance-normalized life-cycle CO2 emissions of plug-in hybrid and battery electric vehicles are higher to their counterpart gasoline powered vehicles. The CO2 emissions comparison results can vary based on the location and time of electricity generation. Therefore, our results confirm that benefits of promoting electric vehicles should consider temporal and spatial aspects of electricity generation.  相似文献   

2.
Summary Results of a performance study of diesel ram-dump cars and electric cable-reel shuttle cars, conducted at an underground coal mine in the Warrior Basin of Alabama, are presented. Time-study data, obtained over a one-year period, show that the average load and discharge times of the diesel cars are slightly less than those of the electric cars, while the average travel-loaded, travel-empty, in, and out speeds of the diesel cars are slightly greater.Computer simulations, based on frequency distributions from the cycle-time data, show average shift productions for both vehicle types to be very close for two-car and three-car configurations with a haul distance of two crosscuts. However, as the haul distance increases, the diesel cars outproduce the electric cars.Results of a maintenance-cost comparison are presented for the sake of general interest and should not be considered as valid comparison, since the electric cars are approximately three years older than the diesel cars. The results show preventive maintenance costs to be much greater for a diesel car on both permonth and per-ton bases, and the total maintenance cost for a diesel car to be significantly higher on a permonth basis, but significantly less on a per-ton basis.  相似文献   

3.
The health risks presented by noxious vehicle emissions inside tunnels has been amplified due to the increasing use of roadway tunnels. Particularly, for adjacent roadway tunnels, vehicular emissions from the upstream tunnel can further deteriorate the air quality within the following tunnels. A scale vehicle tunnel model was designed to experimentally modelled the airflow and pollutants dispersion in contiguous roadway tunnels. The channelling effect on pollutants dispersion between adjacent roadway tunnels was studied, and factors such as ventilation speed, open road section length, traffic condition (e.g. car free, car running and traffic congestion) were considered. Pollutants mass flow rate ratio between downstream and upstream tunnels was calculated to evaluate the variation of the entrained pollutants amount. For the car free condition, pollutant can be easily entrained into the downwind tunnel when the gap distance between roadway tunnels decreased. For the car running condition with fixed tunnel gap distance, the traffic speed variation barely changed the pollutants mass flow rate ratio. Furthermore, evident influences on pollutants concentration were observed from continuous congestion and partial congestion. Lastly, numerical simulation using computational fluid dynamics approach was conducted for the car free scenario, and reasonably good agreements were found for pollutants concentration ratio compared with the experimental data. The results yielded from this study further quantified the relationships among different influential factors on the pollutants dispersion between roadway tunnels, and can contribute to an improved tunnel ventilation system design, especially for the downstream tunnel.  相似文献   

4.
F. Freund  D. Sornette   《Tectonophysics》2007,431(1-4):33
We propose a mechanism for the low frequency electromagnetic emissions and other electromagnetic and electric phenomena which have been associated with earthquakes. The mechanism combines the critical earthquake concept and the concept of crust acting as a charging electric battery under increasing stress. The electric charges are released by activation of dormant charge carriers in the oxygen anion sublattice, called peroxy bonds or positive hole pairs (PHP), where a PHP represents an O3X/OO YO3 with X,Y = Si4+,Al3+,…, i.e. O− in a matrix of O2− of silicates. We propose that PHP are activated by plastic deformations during the slow cooperative build-up of stress and the increasingly correlated damage culminating in a large “critical” earthquake. Recent laboratory experiments indeed show that stressed rocks form electric batteries which can release their charge when a conducting path closes the equivalent electric circuit. We conjecture that the intermittent and erratic occurrences of EM signals are a consequence of the progressive build-up of the battery charges in the Earth crust and of their release when crack networks percolate through the stressed rock volumes, providing a conductive pathway for the battery currents to discharge. EM signals are thus expected close to the rupture, either slightly before or after, that is, when percolation is most favored. The proposed mechanism should be relevant for the broader understanding of fractoemissions.  相似文献   

5.
In this study, it was performed a comparison of the performance and emissions of two methyl ester fuels: one obtained from animal fat and the other from crude canola oil, in a compression-ignition engine against diesel fuel. The experimental results compared with diesel fuel showed that significant reductions could be obtained by biodiesel derived from animal fat in carbon monoxide and oxides of nitrogen emissions. Carbon dioxide emissions showed a trend of decreasing with the biodiesel fuels. An increase in brake specific fuel consumption was observed for different biodiesel fuels when compared with diesel fuel. It was concluded that animal tallow methyl ester performed better than canola oil methyl ester, whereas slightly higher brake torque is observed with canola oil methyl ester.  相似文献   

6.
Using a portable emissions measurement system, 16 gasoline passenger cars were tested on a fixed route consisting of different types of roads in Macao and the data were normalized with the vehicle-specific power bin method. The normalized HC, CO and NO X emission levels of the seven passenger car samples with model year older than 2000 were 3.19 ± 5.04, 14.59 ± 22.88, 2.57 ± 2.12 g/km, respectively. The HC, CO and NO X emission levels of other newer samples were 0.02 ± 0.02, 0.23 ± 0.29 and 0.10 ± 0.13 g/km, respectively. The scrappage of old passenger cars in Macao should be a high priority to control the total emissions of motor vehicles. Based on relative emission levels, a clear and similar pattern for gaseous pollutants and fuel consumption with driving conditions was identified. The emissions of HC, CO and NO X are best fitted to average speed with inverse functions. Fuel consumption is best fitted to average speed with a power function. Compared to the average driving conditions, the emission factors of HC, CO and NO X and fuel consumption of gasoline passenger cars during the rush hours on the Macau Peninsula will be increased by 61, 55, 45 and 90 %, respectively. This situation will deteriorate by 2015 if no further transportation management strategies are implemented in Macao. To save energy and mitigate the air pollutant emissions in the urban area, improved traffic planning and travel demand management are also necessary.  相似文献   

7.
This study investigates the utilization of landfill biogas as a fuel for electrical power generation. Landfills can be regarded as conversion biogas plants to electricity, not only covering internal consumptions of the facility but contributing in the power grid as well. A landfill gas plant consists of a recovery and a production system. The recovery of landfill gas is an area of vital interest since it combines both alternative energy production and reduction of environmental impact through reduction of methane and carbon dioxide, two of the main greenhouse gases emissions. This study follows two main objectives. First, to determine whether active extraction of landfill gas in the examined municipal solid waste sites would produce adequate electric power for utilisation and grid connection and second, to estimate the reduction of sequential greenhouse gases emissions. However, in order to optimize the designing of a plant fed by biogas, it is necessary to quantify biogas production over several years. The investigation results of energy efficiency and environmental impact of biogas utilization in landfills are considering satisfactory enough both in electric energy production and in contribution to greenhouse gases mitigation.  相似文献   

8.
The United States is one of the world's leaders in electricity production, generating about 4116 billion kWh in 2021, of which coal accounted for 21.8% of the total. This study applies an integrated approach using both terrestrial and satellite data to specifically examine emissions from coal-fired power plants and its spatial extent. The study also highlights the effectiveness of government policies to reduce emissions. It was found that emission of pollutants from the country's energy sector has been steadily declining, with annual emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) decreasing from the US electric power sector between 1990 and 2020 by 93.4% and 84.8%, respectively, and carbon dioxide (CO2) by 37% between 2007 and 2020. Although overall emissions from coal-fired power plants are declining, some individual plants have yet to install environmental equipment to control emissions. According to US government data, major emitters of SO2, NOx, and CO2 in the US are the Martin Lake power plant in East Texas, the Labadie power plant near St. Louis, Missouri, and the James H Miller Jr plant near Birmingham, Alabama. This study also integrates TROPOMI satellite data to detect point emissions from individual power plants. While the highest levels of measured pollutants were over the country's major cities and areas of fossil fuel extraction, TROPOMI could clearly distinguish the pollution caused by power plants in more rural areas. Although the US has made great strides in reducing emissions from coal-fired power plants, these plants still represent a major source of pollution and remain a major concern. Totally eliminating coal as a power source will be difficult with the higher power demands resulting from the transition to electric automobiles.  相似文献   

9.
Dynamic behavior of cigarette smoke particles inside the cabin of cars is investigated and the respirable suspended particles concentration during and after smoking cigarette is predicted in this study. This model is based on mass balance equations. Mechanisms of deposition on the surfaces and the exchange of air in the cabin are considered as sinks for emitted particles. The coagulation is accounted as a sink for smaller particles and as a source for larger particles. The various scenarios of smoking in the cars available in the literature are simulated in this study. Good agreement between the results of the present model and the experimental data, as well as the predictions of other available models, is achieved. The mean respirable suspended particle concentration in different scenarios is estimated and compared with Environmental Protection Agency’s health-based standards in order to specify the situations with respirable suspended particles concentrations exceeding the allowable limits. The results show that the concentration of particles due to the smoke of a single cigarette in a stationary medium sized car with the air conditioner off is 33.6 μg/m3 and nearly reaches the limits appointed by the Environmental Protection Agency for a 24 h incremental exposure (35 μg/m3). Corresponding values for moving cars have also been calculated and compared with the standards.  相似文献   

10.
马冰  贾凌霄  于洋  王欢  陈静  钟帅  朱吉昌 《中国地质》2021,48(2):347-358
碳中和是当前世界关注的热点,地球科学可以在其中发挥很大的作用。在国际上,政府间气候变化专门委员会、国际能源署、能源转型委员会,以及在国家层面,政策咨询小组已就CO_2减排可能的实现方式提出了一系列模型和预测情景,表明要实现碳中和,电将代替化石燃料成为全球能源的主要载体。在全球迫切需要减排的背景下,地球科学为实现《巴黎协定》气候目标提供地质解决方案至关重要,主要科学问题涉及:储热与地热;干热岩;水电储能;压缩空气储能;核能;碳捕集与储存;氢经济;能源转型需要的矿产原材料。这就需要地球科学:一是对岩石进行地球化学和地质体的岩石力学特征描述,以便在可能开展脱碳的地区储存CO_2和建立绿色能源系统;二是进一步揭示电动汽车电池和风力涡轮机等所需矿产资源的起源和成因;三是从小型实验室尺度扩大到试点、工业化和商业化全尺度规模;四是要了解公众对地下脱碳技术的态度,保证项目安全性。碳中和目标为地球科学研究提供了新的机遇,未来发展需要从多方面提供支持;提高对地球科学在实现脱碳方面关键作用的认识,并发展技术,打造产业链,实现可持续发展。  相似文献   

11.
In order to reduce the level of atmospheric pollution caused by vehicle engine emissions, application of a novel technique based on fuel magnetization has been tested in this study aiming at improving fuel efficiency and reducing the rate of gas emissions into the environment. Two experiments were conducted, each using a different type of magnetic device. The first type of magnetic device is installed within the fuel tank and the second is installed onto the fuel line. Each experiment was performed on ten separate vehicles from the Dubai Taxi Corporation fleet. When compared to the baseline data, reductions of 70?% for both hydrocarbon and carbon monoxide emissions, and 68?% for oxides of nitrogen were recorded. Results also demonstrated an average fuel consumption reduction of 18?%. These results clearly indicate that the introduction of magnetic field within the fuel supply of engine enhances the combustion process, thereby economizing fuel consumption and reducing the environmentally harmful emissions.  相似文献   

12.
将传统高密度电法系统的供电、测量模块分离,即单独将测量回路分离出来,同时提高供电电压,对压制供电造成的剩余电场和环境噪声电场有明显的应用效果.该方法在保证传统高密度电法的高效率特点的同时,最大优点是突出了高分辨率和高精度.  相似文献   

13.
过渡粗糙平板紊流边界层统计特性试验研究   总被引：1，自引：0，他引：1       下载免费PDF全文
本文应用偏振差动式激光测速仪对过渡粗糙平板紊流边界层的统计特性进行了研究,得到紊动强度、紊动流速的三阶矩、四阶矩、概率密度分布形式、功率谱、自相关系数等特征.分析结果表明,可以根据高阶矩的符号对紊流边界层沿垂向进行分区,并给出了分区标准,同时发现,加糙可使边界层紊流趋于均匀和各向同性,即概率密度分布更接近于高斯分布.  相似文献   

14.
Surface measurements of the atmospheric electrical parameters like Maxwell current, electric field and conductivity studied at the Indian station, Maitri (70.75° S, 11.75° E, 117 m above mean sea level), Antarctica, during austral summer have been analyzed for the years 2001 to 2004. A total of 69 days were selected which satisfied the ‘fairweather’ conditions, i.e., days with absence of high winds, drifting or falling snow, clouds, and fog effects. The diurnal variation curve of electric field and vertical current averaged for 69 fairweather days is a single periodic with a minimum at 03:00 UT and a maximum near 19:00 UT, which is very similar to the Carnegie curve. The correlation coefficient between these measured parameters has a high value (more than 0.9) for all the days. During fairweather days the measured current and field variations are similar and hence it is clear that the conductivity is more or less stable. During magnetically disturbed days, the dawn-dusk potential drop has clear influences on the diurnal variation and it modifies the conductivity. Apart from the day-to-day variation in low latitude thunderstorm activity, there are diurnal, seasonal, inter-annual variations in the electric potential and the currents, as well as solar influences on the measured parameters. This study will help us to examine the impact of solar and geophysical phenomena like solar flares, geomagnetic storms and substorms on the global electric circuit.  相似文献   

15.
The isotopic composition of fossil fuels is an important component of many studies of C sources and sinks based on atmospheric measurements of CO2. In C budget studies, the isotopic composition of crude petroleum and CH4 are often used as a proxy for the isotopic composition of CO2 emissions from combustion. In this study, the C isotope composition (δ13C) of exhaust from the major fossil fuel emission sources in Salt Lake City, USA, was characterized with 159 measurements of vehicle exhaust of various types and eight measurements of residential furnace exhaust. These two sources were found to be isotopically distinct, and differed from global-scale estimates based on average values for crude petroleum and CH4. Vehicle-specific factors such as engine load and operation time had no effect on δ13C of vehicle exhaust. A small difference was found between the mean δ13C of vehicle exhaust collected randomly from different vehicles and the mean δ13C of gasoline collected from multiple fueling stations representing major gasoline distributors in Salt Lake City and the surrounding area. However, a paired comparison of δ13C of exhaust and gasoline for six different vehicles did not show any consistent C isotope fractionation during vehicle combustion. The mean δ13C of crude petroleum processed for local distribution differed slightly from refined gasoline collected at multiple fueling stations, but time lags between processing and transportation cannot be ruled out as an uncontrollable contributing factor. Measured isotope ratios were then combined with fuel consumption statistics to predict the annual cycle of δ13C of fossil fuel emissions for the Salt Lake City metropolitan area. The results showed that the isotopic composition of CO2 emissions from fossil fuel combustion varied by almost 3‰ over the course of the 2002 calendar year. This study illustrates that on a regional scale, the isotopic composition of fossil fuel emissions shows a high degree of both spatial and temporal variability that may influence characterization of C sources and sinks with atmospheric measurements.  相似文献   

16.
魏志强 《探矿工程》2016,43(12):85-89
在老旧城区内采用定向钻进敷设地下管线,常常需要从已有的各类地下建（构）筑物或管线下方穿过,方案设计时就应考虑新建管道与之安全距离的取值问题。以厦门市某110 kV电力电缆的定向钻进工程的实际需求为出发点,在对国内现有规程规范及工程实例调查的基础上,对电力电缆保护管定向钻进敷设安全距离取值的影响因素进行分析,优化工程定向钻进敷设方案,指导该工程的建设,并为类似工程建设提供参考。  相似文献   

17.
The thermal-power plant with combined heat and power (CHP) production located in the city of Zrenjanin (Serbia) is powered by two steam boilers with nominal power of 280 MW each. Considering the problem of increasing pollutant emissions that occur during fossil-fuel combustion process, which is recognized as an arising problem in the CHP Zrenjanin, the accredited Laboratory has been carrying out monitoring and control of the emission production. The emissions have been measured during winter season on boiler B1 for five working regimes of burners, by adjusting the fuel ratio between natural gas and fuel oil. The measurement has been done regarding carbon monoxide, sulphur dioxide, nitrogen oxides (NOx), particulate matter (PM), gaseous inorganic chlorine compounds denoted as hydrogen chloride, and gaseous inorganic fluoride compounds denoted as hydrogen fluoride. Data acquired from those measurements have shown that all parameters except NOx and PM did not exceed emission limits defined under current regulatory statute. According to data analysis of the flue gas emissions, first preventive actions are recommended, then possible actions that could be taken during combustion process, and as last but not least, actions that have to be applied in case when emission problems appears. Regarding CHP control and management problems, some advices are given emphasizing an integral approach to the analysis and optimization of the CHP as the best solution.  相似文献   

18.
不锈钢产业是镍最大的消费领域,对全球镍消费趋势起决定性作用.近年来,电动汽车产业逐渐发展,动力电池对镍需求也逐渐得到重视,该领域的镍消费普遍被认为是最具发展潜力的镍消费领域.本文通过对镍需求的历史和现状进行分析,对未来不锈钢及电动汽车领域等重要部门的镍需求进行了展望,认为未来镍需求将由2019年243万t增长至2030年445万t,其中不锈钢领域仍为其第一大消费领域,电池领域上升为第二大消费领域;通过梳理全球镍资源情况及供应开发情况,认为由于受到疫情冲击,2020年镍矿供需形势紧张状态将有所缓解,但随着未来疫情好转,未来几年内镍仍将处于供需紧张状态;此外,通过梳理镍供应链条,本文认为市场对硫酸镍以及硫化镍矿需求未来有望持续增长,这对镍盐价格将形成有力支撑,对推动全球红土镍矿湿法产能建设也将形成一定促进作用.  相似文献   

19.
结合企业批量定制生产和产品变型开发的特点,定义了坑道钻机的数字化设计流程;提出了坑道钻机数字化设计中的数字化建模、数字化仿真和数字化管理3项关键技术。数字化建模用于建立产品三维模型和装配分析;数字化仿真用于分析产品的动态特性;数字化管理则用于管理产品设计过程及其数据。进而建立了坑道钻机数字化设计平台,包括基础、平台和应用3个层次。结合千米定向钻机开发说明了该数字化设计技术的应用。   相似文献   

20.
To stabilize the atmospheric concentration of greenhouse gases (GHG), a huge reduction of carbon dioxide (CO2) emissions is required. Although some people believe that this necessitates a considerable reduction in the use of fossil fuels or fuel switching, other options are available that allow the use of fossil fuels and reduce atmospheric emissions of CO2. Sequestration of CO2 from fossil fuel combustion in the subsurface could prevent the CO2 from reaching the surface for millions of years. Geological sequestration of CO2 in deep aquifers or in depleted oil and gas reservoirs is a mature technology. Despite the huge quantities of CO2 that can be sequestered in this way, this approach does not provide any economic benefit. This paper discusses a third option, which consists of injecting CO2 in deep coal seams to sequester the carbon and enhance the recovery of coalbed methane (CBM). Waste CO2 from CBM-fueled power plants could be injected into CBM reservoirs to produce more methane (CH4) for the power plant. The 2:1 coal-sorption selectivity for CO2 over CH4 supports the feasibility of operating fossil-fueled power plants without atmospheric CO2 emissions. Other CO2 sequestration technologies, such as ocean disposal and biofixation, are briefly discussed and the suitability of these approaches is evaluated for use in Alberta, Canada.  相似文献   

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