Congestion behavior and tolling strategies in a bottleneck model with exponential scheduling preference

The bottleneck model has been widely used in the past fifty years to analyze the morning commute. To reduce the complexity of analysis, most previous studies adopted discontinuous scheduling preference (DSP). However, this handling destroys the continuity in departure rate and differentiability in travel time and cumulative departures. This paper considers an exponential scheduling preference (ESP), which supposes the unit schedule delay cost for commuters exponentially changes with time. With this scheduling preference, we analytically derive solutions and economic properties of user equilibrium and social optimum in the bottleneck model. The first-best, time-varying toll and the optimal single-step toll scheme with ESP are also studied. Results indicate that ESP eliminates the discontinuity in departure rate and non-differentiability in travel time and cumulative departures, which makes the process of morning commute smooth. The ignorance of ESP will lead to underestimation in the queueing time and bias in travel behavior analysis and policymaking

Association of Adiposity Indices with Platelet Distribution Width and Mean Platelet Volume in Chinese Adults

Hypoxia is a prominent characteristic of inflammatory tissue lesions. It can affect platelet function. While mean platelet volume (MPV) and platelet distribution width (PDW) are sample platelet indices, they may reflect subcinical platelet activation. To investigated associations between adiposity indices and platelet indices, 17327 eligible individuals (7677 males and 9650 females) from the Dongfeng-Tongji Cohort Study (DFTJ-Cohort Study, n=27009) were included in this study, except for 9682 individuals with missing data on demographical, lifestyle, physical indicators and diseases relative to PDW and MPV. Associations between adiposity indices including waist circumstance (WC), waist-to-height ratio (WHtR), body mass index (BMI), and MPV or PDW in the participants were analyzed using multiple logistic regressions. There were significantly negative associations between abnormal PDW and WC or WHtR for both sexes (ptrend<0.001 for all), as well as abnormal MPV and WC or WHtR among female participants (ptrend<0.05 for all). In the highest BMI groups, only females with low MPV or PDW were at greater risk for having low MPV (OR=1.33, 95% CI=1.10, 1.62 ptrend<0.001) or PDW (OR=1.34, 95% CI=1.14, 1.58, ptrend<0.001) than those who had low MPV or PDW in the corresponding lowest BMI group. The change of PDW seems more sensitive than MPV to oxidative stress and hypoxia. Associations between reduced PDW and MPV values and WC, WHtR and BMI values in Chinese female adults may help us to further investigate early changes in human body

Comparative studies on phosphate ore flotation collectors prepared by hogwash oil from different regions

In order to compare the differences between variations of phosphate ore flotation collectors prepared by hogwash oils, JZQ-F collectors were prepared by the hydrolysis method using four types of hogwash oils from different regions in China. The components of the hogwash oils were determined using Fourier transform infrared spectroscopy (FIIR) spectra analysis, while the components of the JZQ-F were determined through gas chromatography–mass spectrometry (GC–MS). The flotation effects of the JZQ-F collectors were investigated by flotation experiments and the adsorption characteristics were determined through the quartz crystal microbalance (QCM-D). Results show that the JZQ-F collector from the Ordos area has 27.43% unsaturated fatty acids. JZQ-F collectors from Beijing, Qingdao, and Dongguan areas contain over 62% of unsaturated fatty acids, which can acquire phosphorous concentrates with a the grade of P2O5 above 31.96% and the recovery higher than 91.52%. These three collectors have a larger adsorption capacity, faster adsorption rate, and stronger adsorption structure on apatite surface, which contributed to a good adsorption performance and a favorable flotation effect. Keywords: Hogwash oil, Flotation collector, Saturated fatty acid, Unsaturated fatty acid, Adsorptio

Role of Pt Loading in the Photocatalytic Chemistry of Methanol on Rutile TiO2(110)

As a cocatalyst, Pt is well-known for accepting photoexcited electrons and lowering the overpotential of hydrogen production in photocatalysis, being responsible for the enhanced photocatalytic efficiency. Despite the above existing knowledge, the adsorption of reactants on the Pt/photon-absorber (for example, Pt/TiO2) interface, a prerequisite to understand the photocatalytic chemistry, is extremely difficult to investigate mainly because of the complexity of the powdered material and solution environment. Combining ultrahigh vacuum and well-ordered single crystals, we study the photocatalytic chemistry of methanol on Pt-loaded rutile TiO2(110) using temperature-programmed desorption (TPD) and ultraviolet photoelectron spectroscopy (UPS). Despite the same photocatalytic chemical products (i.e., formaldehyde and surface hydrogen species) as on Pt-free TiO2(110), the subsequent chemistry of surface hydrogen species and the photocatalytic reaction rate are much different. The bridging hydroxyls desorb as water molecules around 500 K on the Pt-free TiO2(110) surface, and by contrast, this desorption channel disappears completely and water and molecular hydrogen desorb at much lower temperature (<300 K) after Pt deposition, which can prevent the recombination of hydrogen species with formaldehyde. More importantly, methanol dissociates into methoxy at the Pt/TiO2(110) interface, which is crucial in the photocatalytic chemistry of methanol on TiO2 surfaces because methoxy is a more effective hole scavenger than methanol itself. The photocatalytic chemical reaction rate is increased by nearly 1 order of magnitude after 0.12 monolayer Pt deposition. This work suggests that Pt loading can promote the dissociation of methanol into methoxy and lower the desorption barrier of molecular hydrogen, which may work cooperatively with separating photoexcited charges to enhance the photocatalytic efficiency. Our work implies the importance of the cocatalysts in affecting the surface structure and adsorption of reactants and products and then improving the photoactivity, in addition to the well known role in charge separation

Restraining Sodium Volatilization in the Ferric Bauxite Direct Reduction System

Direct reduction is an emerging utilization technology of ferric bauxite. However, it requires much more sodium carbonate than ordinary bauxite does. The volatilization is one of the most significant parts of sodium carbonate consumption, as reported in previous studies. Based on the new direct reduction method for utilization of ferric bauxite, this paper has systematically investigated factors including heating temperature, heating time, and sodium carbonate dosage influencing sodium volatilization. For the purpose of reducing sodium volatilization, the Box–Benhken design was employed, and the possibility of separating iron and sodium after direct reduction was also investigated

Photocatalytic chemistry of methanol on rutile TiO2(011)-(2 x 1)

Photocatalytic chemistry of methanol on the reconstructed rutile TiO2(011)-(2 x 1) surface upon 266 nm and 400 nm light excitation has been investigated quantitatively using the post-irradiation temperature-programmed desorption (TPD) method. Photochemical products such as formaldehyde, methyl formate and water, which result from the recombination of surface bridging hydroxyls through the abstraction of lattice oxygen atoms, have been identified under both 266 nm and 400 nm light irradiation. However, ethylene is detected only under 266 nm light irradiation. Through an analogy experiment, ethylene production is attributed to the photochemistry and the following thermochemistry of formaldehyde. The absence of the ethylene signal under 400 nm light is consistent with the significantly lower conversion at this wavelength compared with 266 nm. The photocatalytic reaction rate of methanol is also wavelength dependent. Possible reasons for the photon energy dependent phenomena have been discussed. This work not only provides a detailed characterization of the photochemistry of methanol on the rutile TiO2(011)-(2 x 1) surface, but also indicates the importance of photon energy in the photochemistry on TiO2 surfaces

Improvement of Sodium Leaching Ratio of Ferric Bauxite Sinter after Direct Reduction

The sodium leaching ratio (ηN) of ferric bauxite direct reduction process is much lower than that of ordinary bauxite; thus, the former consumes more sodium than the latter. ηN can be promoted by increasing the dosage of sodium or restricted by increasing the heating temperature and time. However, the restriction effect of heating temperature is 16.67 times larger than that of heating time, and the restriction effect decreases 47.03 times faster when heating temperature increases than that process of heating time. These imply that ηN improves with the increasing sodium carbonate dosage and the decreasing heating temperature

Interaction of Atomic Deuterium with Rutile TiO₂(011)-(2×1)

Inspired by the significance of hydrogen–solid interaction in hydrogen energy and catalysis, adsorption, diffusion, and desorption behaviors of deuterium atoms in rutile TiO2(011) have been investigated by temperature-programmed desorption (TPD) and ultraviolet photoelectron spectroscopy (UPS). Upon exposure, a small portion of D atoms adsorb at surface oxygen sites, resulting in the band gap states at 1.35 eV below the Fermi level and desorbing as water at ∼400 K. Most of the D atoms will diffuse into the bulk due to the relatively low activation barrier and the huge capacity of the solid material. These bulk D species desorb as D2/HD between 500 and 800 K. While the desorbing D2O from surface hydroxyls saturates at ∼0.10 monolayer (ML), the yielding D2 is about 96 ML (equivalent coverage) at the largest atomic D exposure of 4.54 langmuir and no saturation trend has been observed in the present work. Detailed analysis indicates the bulk D will diffuse back to the surface and recombine as D2 at elevated temperatures. The differences between the behavior of H­(D) in rutile TiO2(110) and TiO2(011) have been discussed by considering the presence of additional bridging oxygen atoms between the in-plane and topmost ones on the latter surface. The striking finding that most surface D atoms diffuse into the bulk of rutile TiO2(011) will not only broaden our understanding of the interaction of H/D with the prototypical metal oxide material but also provide clues to investigate the mechanism of H/D involving reactions over TiO2 catalysts, for example, hydrogen evolution and hydrogenation