On urban arterials, travel time variability is largely dependent on the variability in the delays vehicles experience at signalized intersections. The interpretation of delay evolvement at intersections will give a comprehensive insight into arterial travel time variability and provide more possibilities for travel time estimation. Accordingly, an analytical model is proposed to study delay variability at isolated, fixed-time controlled intersections. Classic cumulative curves are utilized to derive average delay (per cycle) formulas by assuming a deterministic overflow queue. Then, an analogy with the Markov chain process is made to clarify the mechanism of stochastic delays and overflow queues at signalized intersections. It was found that, in undersaturated cases, the shape of the delay distribution changes very little over time, whereas for saturated and oversaturated cases the delay distribution is time-dependent and becomes flatter with an increasing number of cycles. The analysis of arrival distributions, e.g., Poisson and binomial, produces the conclusion that the variability of arrivals has a significant effect on delay estimates in both undersaturated and oversaturated conditions. A larger variance of arrival flow results in a larger variance of delay distribution. All of these analyses can help road authorities to gain insights into arterial travel time variability.

The static drill rooted nodular pile is a new type of pile foundation consisting of precast nodular pile and the surrounding cemented soil. This composite pile has a relatively high bearing capacity and the mud pollution will be largely reduced during the construction process by using this type of pile. In order to investigate the bearing capacity and load transfer mechanism of this pile, a group of experiments were conducted to provide a comparison between this new pile and the bored pile. The axial force of a precast nodular pile was also measured by the strain gauges installed on the pile to analyze the distribution of the axial force of the nodular pile and the skin friction supported by the surrounding soil, then 3D models were built by using the ABAQUS finite element program to investigate the load transfer mechanism of this composite pile in detail. By combining the results of field tests and the finite element method, the outcome showed that the bearing capacity of a static drill rooted nodular pile is higher than the bored pile, and that this composite pile will form a double stress dispersion system which will not only confirm the strength of the pile, but also make the skin friction to be fully mobilized. The settlement of this composite pile is mainly controlled by the precast nodular pile; meanwhile, the nodular pile and the surrounding cemented soil can be considered as deformation compatibility during the loading process. The nodes on the nodular pile play an important role during the load transfer process, the shear strength of the interface between the cemented soil and the soil of the static drill rooted pile is larger than that of the bored pile.

Thermoporometry (TPM) is a calorimetric-based technique for characterizing pore structure according to the freezing and melting point depression of liquid confined in pores which attributes to a varying phase-transition free energy by interface curvature. TPM has demonstrated an emerging success in applications for determining the mesopores of cement-based materials in recent decades. To improve its resolution and accuracy, this paper discussed these factors which show a great influence on the baseline heat flow and the derived pore structure using two molecular sieves with discontinuous size for calibration, referring to the sample handling, the mass of sample and the varying temperature. The pore size distributions of ordinary and high-strength concrete by TPM were favorably compared to the results taken by nitrogen adsorption/desorption (NAD) and mercury intrusion porosimetry (MIP). The results illustrated that both the accuracy and resolution improve with the decreasing cooling/heating rate until 1 °C/min; however, if the rate is too slow, it can lead to an unstable result. The mass of the sample tested has much less an effect on the accuracy when it increases to more than 30 mg. TPM is demonstrated to be more accurate to characterize the mesopores with the size bigger than 4 nm as compared to NAD and MIP.

The evaluation of the seismic stability of an expanded municipal solid waste (MSW) landfill is very important in seismic prone zones. In this paper, the pseudo-dynamic method was used to calculate the average safety factor for the expanded landfill with a trapezoidal berm based on under-berm failure conditions. Furthermore, the effects of the variation of parameters such as the amplification factor, seismic coefficient, height of berm, angle of back slope of berm, and depth of waste mass at the back slope on the seismic stability of the landfill were studied. The results indicated that the influences of the vertical seismic coefficient, height of berm, and angle of the back slope of the berm on the seismic stability of the landfill are weakened as the amplification factor increases, but the influence of the horizontal seismic coefficient on the seismic stability of the landfill is strengthened. On the other hand, a certain ratio of the height of the waste mass above the back slope to the depth of waste mass at the back slope, or the reasonable consideration of the magnitude of the amplification factor will be conducive to the seismic design of the landfill. In addition, the results obtained by the pseudo-static and pseudo-dynamic methods were compared.

In this study, drained and undrained triaxial tests under isotropic and anisotropic consolidations were conducted on reconstituted samples of Babolsar sand, which underlies a densely populated, seismic region of the southern coast of the Caspian Sea, Mazandaran, Iran. It was demonstrated that the sand experienced all possible states of liquefiable soil: flow failure, limited flow, and dilation. The steady-state and flow liquefaction lines of this sand were presented and compared with previously tested sands. It is shown that the initial stress anisotropy can affect the potential of volume change and pore pressure generation. The steady-state line (SSL), however, remains identical for the isotropically and anisotropically consolidated specimens under drained and undrained conditions. The tests data were then analyzed in order to investigate the liquefaction susceptibility of this sand in terms of parameters such as the state parameter, relative state parameter index, and lateral earth pressure ratio at failure.

Rainwater and run-off from three kinds of impervious surface in the Shanghai urban area, China were sampled. Polycyclic aromatic hydrocarbons (PAHs) were measured in the samples, and their sources were assessed. The mean sum of the 16 PAH concentrations measured in rainwater and run-offs from ceramic tiles, asphalt roofs, and asphalt roads were 873, 1404, 1743, and 4023 ng/L, respectively. The PAH concentrations found in this study were moderate compared to PAH concentrations found in run-offs in other studies. The main PAH components in the rainwater, roof run-off, and asphalt road run-off samples were 3-ring PAHs, 3–4-ring PAHs, and 4–6-ring PAHs, respectively. Source apportionment results indicated that combustion (47.4%–55.5%) and vehicular emissions (30.5%–33.0%) were the major contributors to PAHs in roof run-off. Vehicular emissions were the most significant contributors to asphalt road run-off (47.2%), followed by combustion (23.5%), and petroleum (16.3%). Vehicular emissions and coal and natural gas combustion are therefore the most significant sources of PAHs in run-off from impervious surfaces in the Shanghai urban area.

Solubility of 2-amino-6-chloropurine in Mitsunobu solvents could be significantly improved after its exocyclic amino group is protected via N-tert-butoxycarbonylation. The bis-Boc protected 2-amino-6-chloropurine also shows excellent activity and N9 selectivity in the coupling with various alcohols by a Mitsunobu reaction. Then, a new practical and efficient method is established for the synthesis of penciclovir (PCV) from bis-Boc-2-amino-6-chloropurine 9 and the side chain of 5-(2-hydroxyethyl)-2,2-dimethyl-1,3-dioxane 5—the latter being a more easily prepared cyclic precursor of the diacetate side chain used in the conventional process. The coupling of 9 with 5 proceeded regioselectively at a N9 position of purine derivative for a good yield under Mitsunobu conditions.