Effects of speed-control measures on the safety of unsignalized midblock street crossings in China

<p><b>Objective</b>: The primary objective of this study was to evaluate the effects of different speed-control measures on the safety of unsignalized midblock street crossings.</p> <p><b>Methods</b>: In China, it is quite difficult to obtain traffic crash and conflict data for pedestrians using such crossings, mainly due to the lack of traffic data management and organizational issues. In light of this, the proposed method did not rely on such data, but considered vehicle speed, which is a leading contributing factor of pedestrian safety at mid blocks. To evaluate the speed reduction effects at different locations, the research team utilized the following methods in this study: (1) testing speed differences—on the basis of the collected data, statistical analysis is conducted to test the speed differences between upstream and crosswalk, upstream and downstream, and downstream and crosswalk; and (2) mean distribution deviation—this value is calculated by taking the difference in cumulative speed distributions for the two different samples just mentioned. In order to better understand the variation of speed reduction effects at different distances from speed-control facilities, data were collected from six types of speed-control measures with a visual range of 60 m.</p> <p><b>Results</b>: The results showed that speed humps, transverse rumble strips, and speed bumps were effective in reducing vehicle speeds. Among them speed humps performed the best, with reductions of 21.1% and 20.0% from upstream location (25.01 km/h) and downstream location (24.66 km/h) to pedestrian crosswalk (19.73 km/h), respectively. By contrast, the speed reduction effects were minimal for stop and yield signs, flashing yellow lights, and crossings without treatment.</p> <p><b>Conclusions</b>: Consequently, in order to reduce vehicle speeds and improve pedestrian safety at mid blocks, several speed-control measures such as speed humps, speed bumps, and transverse rumble strips are recommended to be deployed in the vicinity of pedestrian crosswalks.</p

Reloading-displacement curves for blank cement paste after healing.

<p>Reloading-displacement curves for blank cement paste after healing.</p

Schematic overview of most differentially expressed modules identification.

<p>Identifying the most differentially expressed modules include three key steps. First, the GO co-expressed network is constructed by combined the protein-protein interaction network, which was from the HPRD and BioGRID database, and GO gene sets together. The edges of network were weighed by co-expression level between their corresponding linked nodes. Second, functional modules were identified by the weighted Girvan-Newman algorithm <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033653#pone.0033653-Newman1" target="_blank">[32]</a>. Finally, functional modules were ranked on their differential levels between recurrent and non-recurrent tumors which were evaluated by the p-SAGE algorithm <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033653#pone.0033653-Huang1" target="_blank">[38]</a>.</p

SEM-EDS micrographs of damaging specimens at different stages: (a) 30%<i>f</i> (b) 60%<i>f</i> (c) capsules layout at 100%<i>f</i> (d) healing cracks at 100%<i>f</i>.

<p>SEM-EDS micrographs of damaging specimens at different stages: (a) 30%<i>f</i> (b) 60%<i>f</i> (c) capsules layout at 100%<i>f</i> (d) healing cracks at 100%<i>f</i>.</p

Diketopyrrolopyrrole-Based π-Bridged Donor–Acceptor Polymer for Photovoltaic Applications

We report the synthesis, properties, and photovoltaic applications of a new conjugated copolymer (C12DPP-π-BT) containing a donor group (bithiophene) and an acceptor group (2,5-didodecylpyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione), bridged by a phenyl group. Using cyclic voltammetry, we found the energy levels of C12DPP-π-BT are intermediate to common electron donor and acceptor photovoltaic materials, poly (3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), respectively. Whereas P3HT and PCBM are exclusively electron donating or accepting, we predict C12DPP-π-BT may uniquely serve as either an electron donor or an acceptor when paired with PCBM or P3HT forming junctions with large built-in potentials. We confirmed the ambipolar nature of C12DPP-π-BT in space charge limited current measurements and in C12DPP-π-BT:PCBM and C12DPP-π-BT:P3HT bulk heterojunction solar cells, achieving power conversion efficiencies of 1.67% and 0.84%, respectively, under illumination of AM 1.5G (100 mW/cm²). Adding diiodooctane to C12DPP-π-BT:PCBM improved donor–acceptor inter-mixing and film uniformity, and therefore enhanced charge separation and overall device efficiency. Using higher-molecular-weight polymer C12DPP-π-BT in both C12DPP-π-BT:PCBM and C12DPP-π-BT:P3HT devices improved charge transport and hence the performance of the solar cells. In addition, we compared the structural and electronic properties of C12DPP-π-BT:PCBM and C12DPP-π-BT:P3HT blends, representing the materials classes of polymer:fullerene and polymer:polymer blends. In C12DPP-π-BT:PCBM blends, higher short circuit currents were obtained, consistent with faster charge transfer and balanced electron and hole transport, but lower open circuit voltages may be reduced by trap-assisted recombination and interfacial recombination losses. In contrast, C12DPP-π-BT:P3HT blends exhibit higher open circuit voltage, but short circuit currents were limited by charge transfer between the polymers. In conclusion, C12DPP-π-BT is a promising material with intrinsic ambipolar characteristics for organic photovoltaics and may operate as either a donor or acceptor in the design of bulk heterojunction solar cells

Influence of content of microcapsules on flexural strength restoration of cement paste: (a) standard curing (b) water curing.

<p>Influence of content of microcapsules on flexural strength restoration of cement paste: (a) standard curing (b) water curing.</p

Load-displacement curves for blank cement paste during pre-damage: (a) standard curing (b) water curing.

<p>Load-displacement curves for blank cement paste during pre-damage: (a) standard curing (b) water curing.</p

Schematic load-deformation relationship of cementitious material.

<p>Schematic load-deformation relationship of cementitious material.</p

The percentage of known colorectal cancer (CRC) genes in top 50–500 MDMs inferred from German dataset.

<p>Known CRC genes were collected from the PubGene (A) or OMIM (B). The percentages were compared with those in top differentially expressed genes (t-test genes) with the same number of genes in top ranked N modules, or GO gene sets with the same amount of top ranked N modules.</p

Crack penetration of specimens before failure: (a) reference (b) 1% of microcapsules (c) 2% of microcapsules.

<p>Crack penetration of specimens before failure: (a) reference (b) 1% of microcapsules (c) 2% of microcapsules.</p