Experimental Investigation on Contribution of CFRP Attachment to Durability of Reinforced Concrete Structure Subjected to Chloride Attack

The function of externally-bonded carbon fiber reinforced polymer （CFRP） in preventing chloride from entering into concrete is verified by experiment. The results show that externally-bonded CFRP can be considered as a part of corrosion prevention system of strengthened concrete structures subjected to chloride ingress, and the contribution of CFRP should be considered in evaluation of durability of reinforced concrete structures with externally-bonded CFRP. With the effective shielding function of CFRP considered, an equation for residual lifetime prediction of concrete structures with externally-bonded CFRP is derived from Fick＇s dispersion law. CFRP has two functions for coastal concrete structures, including strengthening and increasing durability as part of corrosion prevention system.     

B级碳素船体钢焊接接头耐蚀性研究

通过室内腐蚀挂片及电化学测量试验 ,研究了B级碳素船体钢三种常见焊接接头的耐海水腐蚀性能。结果表明 :在海水中 ,接头的焊缝区最易受到腐蚀 ,其次为母材 ,热影响区腐蚀最轻 ;几种接头相比 ,B级碳素船体钢与J4 2 2焊条匹配后焊接接头的综合耐蚀性高于其与J50 7和H0 8MnSi2A两种焊接材料匹配后接头的耐蚀性。     

同步环用碳纤维复合材料的摩擦学特性评价及研究

根据我国制定的同步环摩擦材料的试验室评价方法和规范,对3种同步环用碳纤维复合材料进行了摩擦学特性研究。结果表明,碳纤维复合材料具有优良的摩擦学特性,其性能与碳纤维形态特性、材料孔隙率及添加材料的性能密切相关,但其组成和织构的差异对摩擦学特性有较大影响,因此在设计和生产中必须进行摩擦学特性评价试验。     

CFRP圆柱螺旋弹簧强度预测理论及仿真

针对实心结构形式的碳纤维复合材料(CFRP)圆柱螺旋弹簧进行了建模分析,明确了相关的设计参数,提出了碳纤维复合材料圆柱螺旋弹簧的强度预测理论,并进行了算例分析.将理论预测结果与仿真结果进行了比较,结果表明,理论预测值与仿真值的误差较小,该预测理论可用于碳纤维复合材料圆柱螺旋弹簧的强度设计中.     

Detecting the Resistivity Distribution of Carbon Fiber Reinforced Concrete by Electrical Resistance Tomography Method

According to the principle of electrical resistance tomography （ ERT）, the resistivity distribution of the carbon fiber reinforced concrete （CFRC） in the sensing field can be measured by injecting exciting current and measuring the voltage on the sensor electrode arrays installed on the surface of the object. Therefore, measurement of the resistivity distribution of CFRC is divided into first measuring the boundary conditions and then inversely computing the resistivity distribution. To reach this goal, an ERT system was constructed, which is composed of a sensor array unit, a data acquisition unit and an image reconstruction unit. Simulations of static ERT was performed on set-ups with many objects spread in a homogeneous background, and a simulation of dynamic ERT was also done on a rectangular board, the resistivity of which was changed within a small domain of it. Then, the resistivity distribution of a CFRC sample with a circlar hole as the target was detected by the ERT system. Simulation and experimental results show that the reconstructed ERT image reflects the resistivity distribution or the resistivity change of CFRC structure well. Especially, a small change in resistivity can be identified from the reconstructed images in the simulation of dynamic ERT images.     

Airline energy efficiency measures considering carbon abatement: A new strategic framework

In this paper, airline energy efficiency is divided into two stages: Operations Stage and Carbon Abatement Stage. This new two-stage operating framework is a modification of existing ones. Then the model, Network SBM with weak disposability, is presented to evaluate the efficiency of 22 international airlines from 2008 to 2012. The results show that: (1) Most airlines’ energy efficiencies have not declined in the period. (2) The average efficiency of European airlines is higher than that of non-European airlines. (3) Non-European airlines have smaller advancements in efficiency score than European airlines. (4) Most airlines’ efficiencies in Operations Stage are higher than Carbon Abatement Stage.     

Communicating transportation carbon dioxide emissions information: Does gender impact behavioral response?

General concern and knowledge on climate change have been increasingly studied over the past decades. Gender differences have been found for general environmental concern and knowledge, but mixed findings exist with respect to climate change. In transportation, research has examined potential relations between environmental attitudes and transportation behavior, with mixed findings as well. Recently, the use of carbon dioxide (CO₂) emissions information to influence choice has been tested with women being found more willing to pay to reduce their personal impacts, suggesting that women are either more willing to change or that their response to information on climate change is stronger. However, those studies used CO₂ mass and studies that examined understanding of CO₂ information as a mass have found that people struggle to understand it. If concern and knowledge about climate change differ amongst individuals, then, according to theories such as the Transtheoretical Model, the type of information used to motivate choices is likely important. Using a unique data set (n = 236) it is possible to take a first look at how gender might affect concern, knowledge, and action in terms of transportation and climate change. Further, it is also possible to examine behavioral responses to transportation climate change information. Finally, an empirical analysis is conducted of the effect of how the information is presented might differ by gender. Thus, this work aims to investigate whether gender differences might contribute to the explanation of individual behavioral responses (from concern to action) in a transportation climate change context.     

Carbon and energy footprints of electric delivery trucks: A hybrid multi-regional input-output life cycle assessment

Due to frequent stop-and-go operation and long idling periods when driving in congested urban areas, the electrification of commercial delivery trucks has become an interesting topic nationwide. In this study, environmental impacts of various alternative delivery trucks including battery electric, diesel, diesel-electric hybrid, and compressed natural gas trucks are analyzed. A novel life cycle assessment method, an environmentally-extended multi-region input-output analysis, is utilized to calculate energy and carbon footprints throughout the supply chain of alternative delivery trucks. The uncertainties due to fuel consumption or other key parameter variations in real life, data ranges are taken into consideration using a Monte Carlo simulation. Furthermore, variations in regional electricity mix greenhouse gas emission are also considered to present a region-specific assessment for each vehicle type. According to the analysis results, although the battery electric delivery trucks have zero tailpipe emission, electric trucks are not expected to have lower environmental impacts compared to other alternatives. On average, the electric trucks have slightly more greenhouse emissions and energy consumption than those of other trucks. The regional analysis also indicates that the percentage of cleaner power sources in the electricity mix plays an important role in the life cycle greenhouse gas emission impacts of electric trucks.     

碳纤维布加固混凝土矩形墩柱温度自应力探讨

基于平截面假定和自平衡力系条件,对碳纤维布(CFS)加固的任意形状横截面混凝土构件,建立日照辐射或骤然降温引起的温度自约束变形求解方程。推导CFS加固混凝土矩形墩柱在均匀变化、线性变化和指数变化温度梯度下的温度自应力解析式。与未加固混凝土矩形墩柱温度自应力解析式进行对比分析,结果表明,即使在均匀和线性变化温度梯度下,CFS加固矩形墩柱也会产生温度自应力;在指数变化温度梯度下,CFS中产生可观的温度自应力。所推导的自约束变形求解方程和温度自应力解析式具有一般性,适用于CFS加固混凝土构件和未加固混凝土构件。     

The impact of road grade on carbon dioxide (CO2) emission of a passenger vehicle in real-world driving

To accurately estimate real-world vehicle emission at 1 Hz the road grade for each second of data must be quantified. Failure to incorporate road grade can result in over or underestimation of a vehicle’s power output and hence cause inaccuracy in the instantaneous emission estimate. This study proposes a simple LiDAR (Light Detection And Ranging) – GIS (Geographic Information System) road grade estimation methodology, using GIS software to interpolate the elevation for each second of data from a Digital Terrain Map (DTM). On-road carbon dioxide (CO₂) emissions from a passenger car were recorded by Portable Emission Measurement System (PEMS) over 48 test laps through an urban-traffic network. The test lap was divided into 8 sections for micro-scale analysis. The PHEM instantaneous emission model (Hausberger, 2003) was employed to estimate the total CO₂ emission through each lap and section. The addition of the LiDAR-GIS road grade to the PHEM modelling improved the accuracy of the CO₂ emission predictions. The average PHEM estimate (with road grade) of the PEMS measured section total CO₂ emission (n = 288) was 93%, with 90% of the PHEM estimates between 80% and 110% of the PEMS recorded value. The research suggests that instantaneous emission modelling with LiDAR-GIS calculated road grade is a viable method for generating accurate real-world micro-scale CO₂ emission estimates. The sensitivity of the CO₂ emission predictions to road grade was also tested by lessening and exaggerating the gradient profiles, and demonstrates that assuming a flat profile could cause considerable error in real-world CO₂ emission estimation.