Description: Stable hydrogen isotopes in monsoonal precipitation (δDp) at three sites (Port Blair, Barisal and Darjeeling) reveal the factors governing δDp variations over a south-north gradient across the Bay of Bengal. We found that the δDp at each site continuously decreases from May to September and these trends become more pronounced from south to north. The decreasing trends of downstream δDp closely follow the decreasing trends of upstream stable hydrogen isotopes in water vapor (δDv), which indicates that upstream δDv properties shape initial spatiotemporal patterns of the downstream δDp (“shaping effect”). Additionally, our results demonstrate that, during moisture transport, upstream vertical air motions (convection and downward motion) and topographic relief magnify the amplitude of the decreasing trends of downstream δD (“magnifying effect”). Our findings imply that upstream δD properties and relevant atmospheric and pv topographical conditions along the moisture transport pathway need to be considered collectively to better interpret paleoclimate records.

Description: Sustainability, Vol. 10, Pages 1094: Internal Social Network, Absorptive Capacity and Innovation: Evidence from New Ventures in China Sustainability doi: 10.3390/su10041094 Authors: Wei Shan Chu Zhang Jingyi Wang This research investigates the impact of the internal social network on new venture’s innovation by building a comprehensive structural equation modeling (SEM) that integrates three streams of research: internal social network, innovation, and absorptive capacity. Based on a sample of 279 new ventures from China, the current study’s results show that absorptive capacity plays a full mediating effect in the relationship of the internal social network and innovation. Particularly, among the skill set of absorptive capacity, a mere skill of knowledge acquisition does not guarantee an enhancement of new venture’s innovation. For new ventures to better utilize the social capital generated by the internal network in the process of innovation, they must focus more on the skills of knowledge digestion and knowledge application. The authors further separate the new ventures into two different sub-samples: the new venture supported by mature enterprises (M-type) and the independent new venture (I-type). This study’s findings indicate that the effect of the social network on innovation through knowledge digestion is greater in the M-type sample than in the I-type sample; internal social network heterogeneity in general plays a less important role in improving a new venture’s innovation than internal social network density, for both M-type and I-type new ventures.

Description: The temperature field downstream the lobed mixer under different pre-whirl conditions was studied by numerical method. The influence of pre-whirl on the mixing performance and total pressure loss was summarized. The results show that large-scale streamwise vortices generated by the lobe structure are the key to the rapid mixing of core and bypass airflow. The inlet pre-whirl will strengthen the interaction between streamwise vortices, thus accelerating the mixing of core and bypass airflow. The mixing efficiency and total pressure loss of the lobed mixer increase with the inlet pre-whirl.

Description: Environmental Science & Technology DOI: 10.1021/es202420g

Description: [1]  In this study, a source-oriented version of the Community Multiscale Air Quality (CMAQ) model was developed and used to quantify the contributions of five major local emission source types in Southeast Texas (vehicles, industry, natural gas combustion, wildfires, biogenic sources), as well as upwind sources, to regional primary and secondary HCHO concentrations. Predicted HCHO concentrations agree well with observations at two urban sites (the Moody Tower site at the University of Houston and the HRM-3 site operated by TCEQ). However, the model underestimates concentrations at an industrial site (Lynchburg Ferry). Throughout most of Southeast Texas, primary HCHO accounts for approximately 20-30% of total HCHO, while the remaining portion is due to secondary HCHO (30-50%) and upwind sources (20-50%). Biogenic sources, natural gas combustion, and vehicles are important sources of primary HCHO in the urban Houston area, respectively accounting for 10-20%, 10-30% and 20-60% of total primary HCHO. Biogenic sources, industry, and vehicles are the top three sources of secondary HCHO, respectively accounting for 30-50%, 10-30% and 5-15% of overall secondary HCHO. It was also found that over 70% of PAN in the Houston area is due to upwind sources, and only 30% is formed locally. The model-predicted source contributions to HCHO at the Moody Tower generally agree with source apportionment results obtained from the Positive Matrix Factorization (PMF) technique.

Description: An evaluation of the failures of coal under variable conditions in relation to the stability of coal pillars is an important issue for coal mining. This paper presents the results of an experimental investigation of the mechanical behavior of brittle coal under plane-strain biaxial stress state (PSBSS) compression. The synthetic specimens were meant to test the ductile properties. Modified surface instability detection apparatus was setup to carry out the tests. The results show that the stress-strain curves of coal and synthetic specimens under the PSBSS can be divided into four typical stages, namely original microcrack closure, elastic deformation, sudden stress drop, and residual behavior. The stress-strain curve of coal under PSBSS compression showed periodic stress drops during the post-peak phase, while the curve of the synthetic specimen presented a moderate decrease during the post-peak stage. The remarkable residual strengths of the coal and composites can be observed using these curves, which is vital to the stability of specimens after the failure strength is exceeded. Strain rates have a significant effect on the strength of coal samples under PSBSS compression. Specifically, a higher strain rate indicates a greater peak strength. The failure modes for coal and synthetic specimens are different. During PSBSS compressive tests, coal showed a split failure under different strain rates. For flexible composites, the failure pattern is conjugate shear failure. The study indicated that the Modified Lade and Modified Wiebols-Cook criteria are competent for estimating the defined strength coefficient, which is a ratio proposed to estimate the PSBSS peak strength.

Description: Journal of the American Chemical Society DOI: 10.1021/jacs.7b01431

Description: The unc-51 like autophagy activating kinase 1 and 2 (Ulk1/2) regulate autophagy initiation under various stress conditions. However, the physiology functions of these Ser/Thr kinases are not well-characterized. Here, we show that mice with liver-specific double knockout of Ulk1 and Ulk2 ( Ulk1/2 LDKO) are viable but exhibit overt hepatomegaly phenotype. Surprisingly, Ulk1/2 LDKO mice display normal autophagic activity in hepatocytes upon overnight fasting but are strongly resistant to acetaminophen (APAP)-induced liver injury. Further studies revealed that Ulk1/2 are also dispensable for APAP-induced autophagy process, but are essential for the maximum activation of c-Jun N-terminal kinase (JNK) signaling both in vivo and in isolated primary hepatocytes during APAP treatment. Mechanistically, APAP-induced inhibition of mechanistic target of rapamycin complex 1 (mTORC1) releases Ulk1 from an inactive state. The activated Ulk1 then directly phosphorylates and increases the kinase activity of mitogen-activated protein kinase kinase 4 and 7 (MKK4/7), the upstream kinases and activator of JNK, and mediates APAP-induced liver injury. Ulk1-dependent phosphorylation of MKK7 was further confirmed by a context-dependent phosphorylation antibody. Moreover, the activation of JNK and APAP-induced cell death were markedly attenuated in Mkk4/7 double knockdown hepatocytes reconstituted with an Ulk1-unphosphorylatable mutant of MKK7 compared to those in cells rescued with wild-type MKK7. Conclusion: Together, these findings reveal an important role of Ulk1/2 for APAP-induced JNK activation and liver injury, and understanding of this regulatory mechanism may offer us new strategies for prevention and treatment of human APAP hepatotoxicity. This article is protected by copyright. All rights reserved.

Description: Energies, Vol. 11, Pages 2177: Research on a Plug-In Hybrid Electric Bus Energy Management Strategy Considering Drivability Energies doi: 10.3390/en11082177 Authors: Ye Yang Youtong Zhang Jingyi Tian Si Zhang Plug-in hybrid electric buses (PHEBs) is some of the most promising products to address air pollution and the energy crisis. Considering the switching between different working modes often bring aboutsudden changes of the torque and the speed of different power sources, which may lead to the instability of the power output and affect the driving performance and ride comfort, it is of great significance to develop a real-time optimal energy management strategy for PHEBs to achieve the optimization of fuel economy and drivability. In this study, the proposed strategy includes an offline part and an online part. In the offline part, firstly, the energy conversion coefficient s(t) is optimized by linear weight particle swarm optimization algorithm (LinWPSO), then, the optimization results of s(t) are converted into a 2-dimensional look-up table. Secondly, combined with three typical driving cycle conditions, the gear-shifting correction and mode switching boundary parameters that affect the drivabilityof the vehicle are extracted by dynamic programming (DP) algorithm. In the online part, combined with the s(t), the gear-shifting correction and mode switching boundary parameters which are obtained through offline optimization, the real-time energy management strategy is proposed to solve the trade-off problem between minimizing the fuel consumption and improving the drivability and riding comfort. Finally, the proposed strategy is verified with simulation, the results show that the proposed strategy can guarantee the engine and the electric motor (EM) work in the high-efficiency area with optimal energy distribution while keeping drivability in the variation of driving circle. The overall performance is improved by 18.54% compared with the rule-based control strategy. The proposed strategy may provide theoretical support for the optimal control of PHEB.