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Identifying interactions among river water, groundwater and salt lake brine is important for sustainable exploitation of brine mineral resources. In this study, we investigated the water exchange rate in dry and wet seasons, and assessed the influence of seasonal water exchange on brine concentration and crystallization process in the Nalenggele (NLGL) catchment of Qaidam Basin, China. The results show that the surface water infiltration and groundwater recharge rates in the wet season were 2.81 × 10−3 and 1.15 × 10−3 m3/(s·m) in upstream, 1.63 × 10−2 and 1.53 × 10−2 m3/(s·m) in midstream, and 2.83 × 10−4 and 6.82 × 10−5 m3/(s·m) in downstream, respectively; while their counterparts in the dry season were 9.81 × 10−4 and 5.05 × 10−4 m3/(s·m) in upstream, and 8.34 × 10−3 and 7.78 × 10−3 m3/(s·m) in midstream, respectively. The water exchange strongly influenced brine concentration and crystallinzation process, with brine chemistry belonging to 3K2SO4·Na2SO4 and KCl types in wet and dry seasons, respectively. The strong water exchange in wet season destroyed the water-salt balance, while the low water exchange rate in dry season facilitated preparation of KCl products. [ABSTRACT FROM AUTHOR]

In order to explore the effect of basalt fiber on the basic mechanical properties of hydraulic asphalt concrete, uniaxial compressive and uniaxial tensile tests were carried out by considering 3 fiber lengths and 4 fiber contents. The following conclusions were drawn from the experimental results: With the increase of fiber length, the number of cracks in the compressive failure mode of hydraulic asphalt concrete was gradually decreased. With the increase of fiber content, the number of cracks in the compressive failure mode of hydraulic asphalt concrete was gradually increased. Both the basalt fiber content and fiber length had little effect on the tensile failure mode. With the increase of fiber length, the compressive strength and compressive modulus of hydraulic asphalt concrete tended to decrease first and then increase, while the tensile strength did not change much. With the increase of fiber content, the compressive strength, tensile strength and compressive modulus all tended to increase first and then decrease. The increase of fiber length had little effect on the deformability of hydraulic asphalt concrete, while the increase of fiber content had a recognizable effect on the deformability. Based on the results above, the optimal fiber length and fiber content were 3 mm and 3‰, respectively. Under this working condition, the compressive and tensile strengths were increased by 31% and 42%, respectively, compared with the sample without fiber. Then, the mechanical properties of hydraulic basalt fiber asphalt concrete were examined by the nano-indentation technology to obtain the elastic modulus of the transition interfaces and each constituent phase. Moreover, the scanning electron microscope and X-ray computed tomography (X-ray CT) scanning technologies were applied to reveal the action mechanism of basalt fiber in the hydraulic asphalt concrete. The achievements of this study provide a theoretical basis for the research and application of basalt fiber in the hydraulic asphalt concrete. [ABSTRACT FROM AUTHOR]

The discontinuous dynamic recrystallization (DDRX) nucleation process was investigated during the TMP of a nickel-based superalloy with a coarse columnar-grain structure. Special attention was focused on the formation mechanism of the 'newborn boundary' which separates the free-strain volume from deformed grain. The special grain morphology and large grain size restrained the grain boundary sliding of the studied alloy, and hence made it difficult to form a subboundary through strain induction or twining to separate the free-strain volumes from the deformed grains. This is very different with the classical DDRX theory, where the grain boundary sliding has less restraint and hence leads to grain boundary shearing and the following strain induced boundary or twin boundary. However, the experiment results showed that DDRX took place and developed well during the studied deformation process with restrained grain boundary sliding. It was found that the 'newborn boundary', which separates the free-strain volume from deformed grain to close this area, was formed through dislocation piling-up and rearrangement instead of strain induction or twinning caused grain boundary shearing. Hence, a potential nucleation theory was then proposed and discussed, which is expected to enrich the discontinuous dynamic recrystallization theory. [ABSTRACT FROM AUTHOR]

From October 2012 to September 2013, air samples of hexachlorocyclohexanes (HCHs) were collected by polyurethane foam passive air samplers (PUF-PAS) from Caiban Village (CbV), Baihua Village (BhV), Bumeishan Village (BmsV) and Qitang Village (QtV), located in the rural region of Zhangzhou, Southeast China. The test results showed that four HCH isomers (α-, β-, γ-, δ-HCH) were ubiquitous with ∑HCHs concentrations ranging from 4.80 to 41.9 pg/m3 and a mean value of 17.7 pg/m3. A seasonal variation was established in the air HCH levels. The highest ∑HCHs concentration was observed in the autumn whereas the lowest was detected in the spring. The ratio α/γ-HCH, which was used to identify the contamination source, revealed that air HCHs originated mainly from historical technical HCH residues and lindane usage. The health risk of inhalation exposure to atmospheric HCHs, assessed by the inhalation dosimetry methodology, was low and considered negligible for the local residents. [ABSTRACT FROM AUTHOR]

A dog-associated 16S rDNA genetic marker (ED-1) was designed to detect dog fecal contamination in water through a comparative bioinformatics analysis of Faecalibacterium sequences. For the dog fecal samples, ED-1 had 100% specificity, a high positive rate (89% in dog feces and 92.3% in dog fecal–contaminated water samples), and a low detection limit (107 copies/100 mL) in dog-contaminated water samples. Detection of water samples from seven provinces or cities of China showed that ED-1 was stable enough to be applied in practice. Furthermore, the abundance and diversity of dog gut microbiota from two private house pets (PHP) and Third Military Medical University (TMMU) dogs were estimated by using operational taxonomic units, and the significant differences of dog feces were found, as the PHP dogs have a more diverse diet and closer contact with human than dogs in TMMU. However, ED-1 could detect the feces from the two regions, indicating that ED-1 has good reliability. [ABSTRACT FROM AUTHOR]

For making a complex synthetic gene network function as designed, the parameters in the network have to be extensively tuned. In this study, a simple and general approach to rapidly tune gene networks in Escherichia coli was developed, which uses the hypermutable simple sequence repeats embedded in the spacer region between the ribosome binding site and the initiation codon. It was found that the change of sequence length and compositions of the repeated base pairs in 5′UTR contributes together to the changeable expression levels of the target gene. The mechanism of this phenomenon is that the transcriptional process makes greater impact on the expression level when compared to the translational process, which is utilized to successfully predict sample gene expression levels over a 50-fold range. The utility of the approach to regulate heterologous ecaA and pepc gene expression in the engineered E. coli for improving succinic acid yield and production has also been demonstrated. When the expression level of ecaA gene was 3.53-fold of the control and the expression level of pepc gene was 1.06-fold of the control, the highest yield of succinic acid and productivity were achieved, which was 0.87 g g and 2.01 g L h, respectively. [ABSTRACT FROM AUTHOR]