AbstractAccurate traffic state information is essential for both travelers and transportation agencies. In the past, traffic condition data were usually collected by a government agency using its own ...sensors. Recently, a number of private sector companies have started selling travel-time and speed data collected using probe vehicles, which provides a viable opportunity to outsource traffic data collection. Because these data sources and their related algorithms are proprietary, the reliability and accuracy of this private sector data is often an important issue for transportation agencies. Previous studies have examined the accuracy of private sector data on freeways, but arterials have not been examined extensively. Arterials represent a fundamentally more challenging environment for probe vehicle data given the larger variance in travel times created by traffic signals and other intermediate access points. In the research, the quality of private sector data on arterials is evaluated by utilizing Bluetooth travel-time data as the ground truth. The evaluation is conducted from two perspectives: the ability to track real-time conditions, and the ability to identify long-term traffic state changes. The study sites are three signalized arterials in the state of Virginia. The results indicate that the private sector data evaluated were not suitable for real-time applications, but could be used to measure long-term traffic state changes for performance measurement programs.
The impact of work zones on mean travel time and travel time reliability has gained attention as agencies focus on performance measurement. Travel time reliability in work zones often has been ...difficult for agencies to quantify because of the time and expense required to collect travel time data. Several private-sector companies have begun to sell travel time data; this availability has created an opportunity to examine cost-effectively work zone impacts on travel time reliability on a broader basis. The Virginia Department of Transportation recently acquired probe vehicle-based travel time data for 2010 from a private-sector data provider. These data were used to calculate measures of travel time reliability at 15 work zones and to examine factors that affected travel time reliability. Travel time reliability was quantified with 95th percentile travel time, a buffer index, and a planning time index. The work zones experienced a statistically significant degradation across all measures of travel time reliability as compared with baseline conditions. Work zone mean buffer index, planning time index, and 95th percentile travel time rates were higher by 48%, 18%, and 16%, respectively. Although lane closures occurred during off-peak periods, work zones that involved lane closures experienced increases in their mean buffer index, planning time index, and 95th percentile travel time with rates of 67%, 23%, and 22%, respectively. Annual average daily traffic per lane and the number of access points per mile were found to have the most obvious relationships with declines in reliability at work zones.
For breakthrough development in solid oxide fuel cells, novel cell architectures integrating better performing materials and cost-effective manufacturing processes with potential for mass production ...must be realised. The present work addresses this on the basis of the recent discovery of acceptor doped rare-earth ortho-niobate proton conductors and the development of a versatile fabrication process. La
0.995Sr
0.005NbO
4−
δ
/NiO anodes are produced by tape-casting and co-lamination of green layers. Their porosity is finely tuned by using a pyrolyzable pore former. La
0.995Sr
0.005NbO
4−
δ
electrolytes are spin-coated using ceramic-based suspensions. Fully dense electrolytes with thickness ranging from 9
μm to 26
μm are obtained after sintering in air at 1350
°C. The cathode layers are then screen-printed. To match thermal expansion and to avoid chemical reaction between the functional layers, special attention is paid to the design of cathode architectures. CaTi
0.9Fe
0.1O
3−
δ
, La
2NiO
4+
δ
and La
4Ni
3O
10 mixed oxygen ion and electron conducting oxides are investigated as either monophase or La
0.995Sr
0.005NbO
4−
δ
-based composite electrodes. The latter gives the whole cell an innovative “semi-monolithic” concept, which can take advantage of the chemical and mechanical stability of La
0.995Sr
0.005NbO
4−
δ
, as well as of inherent material integration. Most promising cell architectures are finally selected based on thermo-mechanical and chemical compatibility of all functional layers.
Thick films cathodes for Solid Oxide Fuel Cells (SOFC) are prepared by dip-coating slurries made of several lanthanum nickelate oxide powders onto yttria stabilized zirconia (YSZ) substrates. The ...processing parameters for the slurries preparation and the multilayers coating have been optimized to obtain homogeneous, crack-free, thick and adherent films after heat treatment.
Objective: Concern has been raised about the potential impact of nanomaterials exposure on human health, and France has decided to implement a timely epidemiological surveillance tool of workers ...likely to be exposed to engineered nanomaterials that could accompany the development of nanotechnologies. Methods: A comprehensive review of the toxicological and epidemiological literature has been conducted together with an exploratory study among French companies producing or handling nanoobjects. Results: A double surveillance system is proposed consisting of a prospective cohort survey and repeated cross-sectional studies. The aim of the cohort is (1) to monitor long-term health effects and (2) to allow of further research. Settingup an exposure registry is the first planned step. Conclusions: The protocol is about to be submitted to the French Government for approval and funding.
Objective Mast cells (MCs) are inflammatory cells present in atherosclerotic lesions and neovascularized tissues. Recently, MCs were shown to modulate abdominal aortic aneurysm (AAA) formation in a ...mouse model. Progression of aneurysmatic disease process may also depend on intraluminal thrombus and neovascularization of the aneurysm wall. Here we investigated the relationship between MCs and inflammation, neovascularization, and the presence of intraluminal thrombus in human AAA. Methods and Results Specimens from AAAs and normal control aortas were analyzed with basic histology, immunohistochemical staining, and quantitative real-time polymerase chain reaction (PCR). Double immunostainings with endothelial cell markers CD31/CD34 and MC tryptase showed that, in contrast to histologically normal aorta, MCs in AAA were abundant in the media, but absent from the intima. Medial MCs and (CD31/CD34)+ neovessels increased significantly in AAA compared with normal aorta ( P < .0001 for both), and the highest densities of neovessels and MCs were observed in the media of thrombus-covered AAA samples. Also, the proportional thickness of aortic wall penetrated by the neovessels was significantly higher in the AAA samples ( P < .0001), and the neovascularized area correlated with the density of medial MCs ( P < .0001). In histologic analysis, the medial MCs were mainly located adjacent to the stem cell factor (SCF)+ medial neovessels. Real-time PCR analysis also showed that mRNA levels of genes associated with neovascularization (vascular endothelial growth factor VEGF, FLT1, VE-cadherin, CD31), and MCs (tryptase, chymase, cathepsin G) were higher in AAA samples than in controls. Demonstration of adhered platelets by CD42b staining and lack of endothelial cell (CD31/CD34) staining in the luminal surface of AAA specimens suggest endothelial erosion of the aneurysm walls. Conclusions The results support participation of MCs in the pathogenesis of AAA, particularly regarding neovascularization of aortic wall.
In 1988, some workers of the pathology group at Padua reported ARVD-like pathologies in 12 of the 49 hearts of young adults who died suddenly, mostly during exertion, in the Veneto region.8 They ...observed a progressive loss of myocardium; lipomatous or fibrolipomatous replacement; and foci of inflammation, degeneration, and necrosis predominantly in the RV. Because cardiac pathologies in this young adult population were not previously reported and were considered as the result of an unknown mechanism, they used the term "right ventricular cardiomyopathy" to describe this disease category. Because their descriptions and subsequent identification of desmosomal mutations as the main cause of this disease,10 ARVD is now commonly known as arrhythmogenic right ventricular cardiomyopathy (ARVC) or is termed with a more generalized name arrhythmogenic cardiomyopathy. Because I am the original person to name this disease ARVD, I feel that I am compelled to discuss the pros and cons of using these terminologies to describe this unfortunate cardiac disease entity.\n I must say that the "force" of "dysplasia" remains strong.
PDF
