Environmental incidents in China:Lessons from 2006 to 2015

Environmental incidents are among the most significant environmental challenges in China. Hundreds of environmental incidents occur every year, endangering human health and ecosystems. In this paper, we conducted an analytical study of environmental incidents from 2006 to 2015 in China. We first examined the spatiotemporal characteristics of the total 5213 incidents based on the statistical data collected from the China Statistical Yearbook on Environment. We then examined the characteristics of the sources of risk, causes of harm and resulting damage of environmental incidents based on first-hand data from 1369 cases collected by the Ministry of Environmental Protection (MEP) of China, which obtains detailed incident information. The results show that (1) there was a significant downward trend in the overall number of environmental incidents between 2006 and 2015, and developed eastern regions were high incidence areas; (2) hazardous chemicals were the main risk stressors; (3) production safety accidents and traffic accidents were the two major causes, and (4) most of these incidents resulted in polluted water and air. This paper is the first to provide a longitudinal analysis of the full scope of environmental incidents across the different regions of China, which has useful implications for policy-making and environmental management

Critical Role of AKT in Myeloma-induced Osteoclast Formation and Osteolysis

Abnormal osteoclast formation and osteolysis are the hallmarks of multiple myeloma (MM) bone disease, yet the underlying molecular mechanisms are incompletely understood. Here, we show that the AKT pathway was up-regulated in primary bone marrow monocytes (BMM) from patients with MM, which resulted in sustained high expression of the receptor activator of NF-κB (RANK) in osteoclast precursors. The up-regulation of RANK expression and osteoclast formation in the MM BMM cultures was blocked by AKT inhibition. Conditioned media from MM cell cultures activated AKT and increased RANK expression and osteoclast formation in BMM cultures. Inhibiting AKT in cultured MM cells decreased their growth and ability to promote osteoclast formation. Of clinical significance, systemic administration of the AKT inhibitor LY294002 blocked the formation of tumor tissues in the bone marrow cavity and essentially abolished the MM-induced osteoclast formation and osteolysis in SCID mice. The level of activating transcription factor 4 (ATF4) protein was up-regulated in the BMM cultures from multiple myeloma patients. Adenoviral overexpression of ATF4 activated RANK expression in osteoclast precursors. These results demonstrate a new role of AKT in the MM promotion of osteoclast formation and bone osteolysis through, at least in part, the ATF4-dependent up-regulation of RANK expression in osteoclast precursors

Critical Role of Activating Transcription Factor 4 in the Anabolic Actions of Parathyroid Hormone in Bone

Parathyroid hormone (PTH) is a potent anabolic agent for the treatment of osteoporosis. However, its mechanism of action in osteoblast and bone is not well understood. In this study, we show that the anabolic actions of PTH in bone are severely impaired in both growing and adult ovariectomized mice lacking bone-related activating transcription factor 4 (ATF4). Our study demonstrates that ATF4 deficiency suppresses PTH-stimulated osteoblast proliferation and survival and abolishes PTH-induced osteoblast differentiation, which, together, compromise the anabolic response. We further demonstrate that the PTH-dependent increase in osteoblast differentiation is correlated with ATF4-dependent up-regulation of Osterix. This regulation involves interactions of ATF4 with a specific enhancer sequence in the Osterix promoter. Furthermore, actions of PTH on Osterix require this same element and are associated with increased binding of ATF4 to chromatin. Taken together these experiments establish a fundamental role for ATF4 in the anabolic actions of PTH on the skeleton

Numerical Simulation of Helicopter Rotor Performance Degradation in Natural Rain Encounter

Sustained flight operation in the rain conditions is still a challenge to a pilot. This problem can be mainly attributed to the aerodynamic performance degradation of aircraft. In this article, in order to quickly understand the influence of rainfall aiming at the engineering application, an approach to predict helicopter rotor performance degradation in heavy rain encounters is presented. Firstly, we develop a computational fluid dynamics- (CFD-) based method of simulation of the blade airfoil under natural rain scenario and different angles of attack in order to obtain a data-driven basis relating to multiple working conditions of the rotating blades for further analysis. Then, these data are studied using a discretization analysis method of rotor aerodynamics. CFD simulations are conducted, including the case of NACA 0012 airfoil with 10 m chord length, and the case of SC1095 airfoil used in a full-scale rotor of UH-60A helicopter. Prediction of helicopter rotor performance degradation is carried out in a thunderstorm heavy rain with the rain rate of 1500 mm/h using this full-scale rotor. The quantitative results indicate that heavy rain dramatically degrades the rotor performance. The maximum percentage decrease in lift coefficient of this full-scale rotor blade airfoil is reached by 12.75%. The maximum percentage increase in drag coefficient of this full-scale rotor blade airfoil is reached by 26.51%. The maximum percentage decrease in averaging lift-to-drag ratio of this full-scale rotor disk is reached by 26.39%

A Novel Inverse Simulation Method of Helicopter Maneuvering Flight

In this article, a degeneration method of inverse simulation is proposed for a helicopter system flying pull-up and slalom maneuvers. This inverse simulation method has been successfully applied, and here, the results are compared with the flight test data and the reference data, which indicate that this method has fidelity and is effective. It is different from conventional inverse simulation methods (i.e., the differentiation method and the integration method), and can improve numerical stability during inverse simulation, because the core principle is to solve the output vector in each simulation time step, by degenerating the system of first-order differential equations into nonlinear equations

Numerical Simulation of Fully Coupled Flow-Field and Operational Limitation Envelopes of Helicopter-Ship Combinations

Landing a helicopter to the ship flight deck is most demanding even for the most experienced pilots and modeling and simulation of the ship-helicopter dynamic interface is a substantially challenging technical problem. In this paper, a coupling numerical method was developed to simulate the fully coupled ship-helicopter flow-field under complete wind-over-deck conditions. The steady actuator disk model based on the momentum source approach and the resolved blade method based on the moving overset mesh method were employed to model the rotor. Two different ship-helicopter combinations were studied. The helicopter flight mechanics model was established and then the influences of coupled airwake on the helicopter were analyzed. Finally, based on the derived rejection criterion of safe landing and the developed numerical method, the flight envelopes for these two ship-helicopter combinations were predicted. The steady actuator disk model was found to be effective in the study of helicopter operations in the shipboard environment. The calculated flight envelopes indicate that an appropriate wind direction angle is beneficial to increasing the allowable maximum wind speed and the operating boundary is affected by the rotation direction of the main rotor

Solvent Extraction of Sc(III) by D2EHPA/TBP from the Leaching Solution of Vanadium Slag

The solvent extraction of scandium by the mixture of di-(2-ethylhexyl) phosphate (D2EHPA) and tri-n-butyl phosphate (TBP) has been investigated in the acidic leaching solution of vanadium slag. Thermodynamic analysis of the species distribution diagrams on the Sc-S-H2O system showed that scandium mainly exists as Sc3+ and Sc(SO4)+, and sulfur mainly exists as HSO4− in the actual leaching solution of vanadium slag (pH = −0.75). The extraction process was studied to optimize various parameters such as the extractant concentration, dosage of TBP, phase ratio, and stirring speed. The results indicated that 83.64% of scandium and less than 2% of co-extracted elements were extracted under optimal conditions. Then, over 95% of the co-extracted elements and less than 1.1% of scandium were scrubbed from the loaded organic phase by 4.0 mol/L of HCl. Finally, 87.20% of scandium was stripped with 2 mol/L of NaOH and 1 mol/L of NaCl at a stripping O/A of 1:1

Accuracy Evaluation of Statically Backcalculated Layer Properties of Asphalt Pavements from Falling Weight Deflectometer Data

This study is to evaluate the dynamic effects of falling weight deflectometer (FWD) loading on the surface deflection of asphalt pavement and the accuracy of statically backcalculated layer moduli from FWD data. The dynamic and static deflections were computed using the spectral element method and the layer elastic theory, respectively, for various pavement structures. The static deflection is considerably larger than the dynamic deflection for typical FWD loading and the normalized difference between static and dynamic deflections increases with increasing distance from the load center and decreases with increasing loading duration. The dynamic deflections were utilized to backcalculate the layer moduli using two static backcalculation procedures, MODULUS and EVERCALC. The backcalculated moduli can be significantly different from the actual moduli. The results indicate that the static backcalculation procedure can lead to significant errors in the backcalculated layer moduli by ignoring the dynamic effects of FWD loading.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author