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441.
11 000 dwt滚装船货舱通风系统的噪声控制 总被引:1,自引:0,他引:1
论述了11 000 dwt滚装船货舱通风系统技术设计及施工设计过程中如何控制货舱噪声的问题,以及针对这些问题所采取的相应措施及方法。 相似文献
442.
为降低市政道路行车噪声,促进废旧轮胎资源化利用,本课题将废旧轮胎橡胶粉应用于铺筑低噪声沥青路面。研究了废橡胶粉干法改性沥青混合料组成设计方法、路用性能、降噪机理以及施工关键技术,并形成了低噪声路面示范工程。 相似文献
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汽油车低温冷起动和常温冷起动排放特性的对比分析 总被引:6,自引:1,他引:6
针对国Ⅲ标准中新规定的-7°的低温冷起动测试,采用对比试验的方法比较了低温冷起动(Ⅵ型试验)和常温冷起动(Ⅰ型试验)整个排放过程中CO、HC和CO2的排放差异。对两种温度条件下的催化器入口温度进行了比较分析。通过对排放特性的比较,简述了汽油车低温冷起动排放控制方法。 相似文献
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447.
Application of a validated primary production model (BLOOM) as a screening tool for marine, coastal and transitional waters 总被引:3,自引:0,他引:3
In order to manage aquatic systems, it is necessary to apply methods relating the environmental variables and system-state parameters with external factors that affect the system. External factors can be natural (i.e. the movement of water) or partly-anthropogenic (i.e. nutrient loads). In addition to the national authorities, who have been implementing environmental policies for several decades, the EU is presently implementing the Water Framework Directive (WFD) aimed at establishing a new set of standards for the ecological and water quality of water systems. Among these are the phytoplankton biomass and composition. Phytoplankton affects turbidity, oxygen depletion, total productivity of the system and the occurrence of (harmful) algal blooms. A range of methods is available to relate phytoplankton to the controlling environmental conditions. Among these are statistical relations for instance of the Vollenweider type as well as deterministic simulation models. At the end of the 1970s, a generic deterministic phytoplankton module called BLOOM was developed, which has since been applied to a wide range of fresh water and marine systems. Here we test the applicability of this model as a screening tool for coastal waters. We conclude that the model is able to reproduce observed chlorophyll levels adequately under a wide range of conditions. Subsequently the model is applied to demonstrate the potential impacts of reductions in nitrogen, phosphorus or both nutrients simultaneously. Depending on which factors are initially controlling, the impacts of these reductions vary considerably both between locations and during the season. While this type of application lacks explicit relations between nutrient concentrations and external loadings, it does consider a number of relevant conditions in a consistent way and requires remarkably little data and effort. It is therefore a valuable screening tool. 相似文献
448.
IntroductionThe conventional passive constrained layerdamping (PCLD) treatments[1~ 3] are applied tomachines and structures widely over the lastcentu-ry because they are reliable and simple,however,they are not intelligent. Once the damping treat-ments are installed,they can not be adjusted andcan not adapt themselves to changeable environ-ment.Recently,active damping has received in-creasing attention in the aeronautic and astronauticindustries because of its significant and adjustabledamp… 相似文献
449.
从城市GDP、交通基础设施、货运量、货运车辆调度、能源和环境6 个要素出发,构建城市货运交通系统动力学模型,对比实施共同配送前后对城市货运交通拥堵、运输费用及货运系统节能减排的效益变化,寻求解决路径. 以济南市为例,确定模型参数及方程,动态仿真实施共同配送的效益. 结果表明:随着载货率提高、平均运距的增长,实施共同配送的边际收益呈递减趋势,配送时间的昼夜错峰调整也有显著影响;在决策区间载货率[70%, 80%]、平均运距[70, 80] km、配送时间昼夜比例[6∶4,7∶3]下,共同配送总体效益最优;节能减排效益仍存在挖掘的潜力,通过提高新能源货运车承担的货运比重,每20%的增加将带来货运系统节能减排平均30%的降低. 相似文献
450.
Driving cycles are an important input for state-of-the-art vehicle emission models. Development of a driving cycle requires second-by-second vehicle speed for a representative set of vehicles. Current standard driving cycles cannot reflect or forecast changes in traffic conditions. This paper introduces a method to develop representative driving cycles using simulated data from a calibrated microscopic traffic simulation model of the Toronto Waterfront Area. The simulation model is calibrated to reflect road counts, link speeds, and accelerations using a multi-objective genetic algorithm. The simulation is validated by comparing simulated vs. observed passenger freeway cycles. The simulation method is applied to develop AM peak hour driving cycles for light, medium and heavy duty trucks. The demonstration reveals differences in speed, acceleration, and driver aggressiveness between driving cycles for different vehicle types. These driving cycles are compared against a range of available driving cycles, showing different traffic conditions and driving behaviors, and suggesting a need for city-specific driving cycles. Emissions from the simulated driving cycles are also compared with EPA’s Heavy Duty Urban Dynamometer Driving Schedule showing higher emission factors for the Toronto Waterfront cycles. 相似文献