In a mechanistic-empirical (ME) pavement design method, the modulus of asphalt concrete (AC) is essential. The in-situ AC modulus can be obtained by the surface wave method (SWM). However, the measured modulus needs to be adjusted to the design frequency values. This study aimed to propose a frequency adjustment method for the in-situ AC seismic modulus. For this purpose, coring and dynamic modulus tests, FWD (Falling Weight Deflectometer) tests, and PSPA (Portable Seismic Pavement Analyzer) tests were carried out in the accelerated pavement test (APT). The master curves generated by the dynamic modulus results correlated well with the moduli determined from the other tests. Based on this relationship, a frequency adjustment factor was developed for the seismic modulus of the undamaged AC layer. For the damaged AC layer, the proposed factor was modified by incorporating the effect of the damage. Finally, to validate the frequency adjustment factor, the measured maximum tensile strains in the APT were compared with the values determined from the adjusted seismic moduli. The results prove that the frequency adjustment factor is appropriate to obtain the design modulus from the surface wave test. The PSPA test is also recommended to obtain the in-situ AC seismic modulus.

A high responsivity and controllable recovery ultraviolet (UV) photodetector based on a tungsten oxide (WO₃) gate AlGaN/GaN heterostructure with an integrated micro-heater is reported for the first time. The WO₃nanolayer was deposited by physical vapor deposition (PVD) for deep UV absorption and the micro-heater was integrated for chip level heating and cooling. Our device when exposed to UV wavelength exhibits a high responsivity of 1.67 × 10⁴A W⁻¹at 240 nm and a sharp cut-off wavelength of 275 nm. More importantly, the persistent photoconductivity (PPC) effect can be eliminated by a novel method, mono-pulse heating reset (MHR), which consists in applying an appropriate pulse voltage to the micro-heater right after the removal of the UV illumination. The recovery time was reduced from hours to just seconds without reducing the high responsivity and stability of the photodetector. The UV detection, high responsivity, high stability, controllable recovery process and low production cost of GaN-based photodetectors make these devices extremely attractive for several applications, such as fire detection and missile and rocket warning.

Asphalt concrete (AC) modulus reduction caused by repeated axle loading significantly affects pavement long-term performance; including when built on a semi-rigid layer. However, quantifying this effect is challenging. The primary objective of this paper was to monitor and evaluate modulus reduction and fatigue damage accumulation at various AC depths utilizing data obtained from two semi-rigid pavement sections. During loading, a non-destructive method, portable seismic pavement analyzer (PSPA), was used to predict the modulus ratio. PSPA test results show that the damage is nonlinear with respect to the loading passes. Also, depth and AC thickness can influence the development of damage. A developed model showed that it could predict the aforementioned nonlinear relationship. The model parameters can be used to identify the damage level at various AC depths. Unexpected compared with previous understanding, the damage in AC layers was found to increased first, then decreased, and finally increased with the depth. Since PSPA is cheap, portable, and easy to apply, this method to identify the damage level in AC layers is proven to be applicable and practical.

Ultrafast photodoping of the Mott insulators, possessing strong correlation between electronic and magnetic degrees of freedom, holds promise for launching an ultrafast dynamics of spins which cannot be described in terms of conventional models of ultrafast magnetism. Here we study the ultrafast laser-induced dynamics of the magnetic order in a novel spin-orbit Mott insulator Sr2IrO4 featuring an uncompensated pattern of antiferromagnetic spin ordering. Using the transient magneto-optical Kerr effect sensitive to the net magnetization, we reveal that photodoping by femtosecond laser pulses with photon energy above the Mott gap launches melting of the antiferromagnetic order seen as ultrafast demagnetization with a characteristic time of 300 fs followed by a sub-10-ps recovery. Nonequilibrium dynamical mean-field theory calculations based on the single-band Hubbard model confirm that ultrafast demagnetization is primarily governed by the laser-induced generation of electron-hole pairs, although the precise simulated time dependencies are rather different from the experimentally observed ones. To describe the experimental results, here we suggest a phenomenological model which is based on Onsager's formalism and accounts for the photogenerated electron-hole pairs using the concepts of holons and doublons.

China has achieved significant progress on wastewater treatment and aquatic environmental protection. However, leakage (in- and exfiltration) of sewer systems is still an issue. By using the statistical data of water and wastewater in 2016 in China, and the person loads (PLs) of water and wastewater in Singapore, the leakage fractions of hydraulic flow, organic carbon (COD), nitrogen (N) and phosphorus (P) mass loading, and in-sewer COD biological removal in the sewer systems of China (except Hong Kong, Macau and Taiwan), Shanghai, Guangzhou and Beijing were reported for the first time. The fractions of hydraulic flow infiltration (13%, Shanghai and Guangzhou) and exfiltration (39%, China) were calculated. Except Beijing, whose sewer networks are under appropriate management with small leakage fractions, the exfiltration fractions of COD (including in-sewer biological COD removal) ranged from 41% (Shanghai) to 66% (China) and averaged 55%; N ranged from 18% (Shanghai) to 48% (China) and averaged 33%; and P ranged from 23% (Shanghai and Guangzhou) to 44% (China) and averaged 30%. The exfiltrated sewage, COD, N and P not only wastes resources, but also contaminates the aquatic environment (especially groundwater) and contributes to 'black and odorous water bodies'. In- and exfiltration in the sewer network leads to low influent COD concentration, C/N ratio and high inorganic solids and inert particulate COD concentrations of many municipal wastewater treatment plants (WWTPs) causing high cost for nutrient removal, poor resource recovery, additional reactor/settler volume requirement and other operational problems. Therefore, tackling sewer leakage is of primary importance to today's environment in China. Recommendations for the inspection of sewer systems and the rehabilitation of damaged sewers as well as the development of design and operation guidelines of municipal WWTPs tailored to the specific local sewage characteristics and other conditions are proposed.

A decade ago, membrane bioreactors (MBR) were considered as a potential technology for replacing conventional activated sludge (CAS) processes. Indeed, MBR experienced a period of rapid development around 2009, especially in China. In recent years, however, there has been a sharp drop in the number of MBR installations all around the world - with the exception of in China. It is important to understand the reasons for this difference between the reactions of China and other countries. High-quality effluent and a smaller MBR footprint are also associated with high energy consumption and operational costs. Therefore, it is necessary to carefully evaluate the advantages and disadvantages of MBR. In this study, a model (including capital and operational costs, operational efficiency and stability, resources saving and recovery and an evaluation of the sustainability index (S_I) of MBR over CAS) was established to comprehensively evaluate the effects of MBR on economy, technology and management. The model calculations of S_I demonstrate S_I > 1.0. This means, briefly put, that MBR is not a sustainable process when compared to CAS, which is extensively applied but generally thought to be an unsustainable process. The sensitivity analysis of both related factors and weighted coefficients in the model reveals that there is almost no possibility of attaining S_I < 1.0 (more sustainable than CAS). For this reason, it is not recommended that MBRs extensively replace CAS when upgrading and constructing wastewater treatment plants (WWTPs). Alternative technologies may be considered, such as aerobic granular sludge (GAS).

The state of the land surface and the water cycle over the South and East Asia can be determined by space observation. New or significantly improved algorithms have been developed and evaluated against ground measurements. Variables retrieved include land surface properties, i.e. NDVI, LAI, FPAR, albedo, soil moisture, glacier and lake levels. Based on these biophysical parameters derived from microwave and optical remote sensing observations, a hybrid remotely sensed evapotranspiration (ET) estimation model named ETMonitor was developed and applied to estimate the daily actual ET of the Southeast Asia at a spatial resolution of 1 km. The changes in glaciers and lakes on the Tibetan Plateau, and the drainage links between glaciers and lakes are determined in this climate-sensitive region.