Laboratory Investigations of Hydraulic Fractures in Naturally Fractured Formations

Researchers have recently realized that hydraulic fracture networks are significant for the exploitation of unconventional reservoirs (tight gas, shale gas, coalbed methane, etc.). Laboratory experiments are proposed to study the evolution of fracture networks in natural fractures. The density of natural fractures and injection rate were selected as the primary dominating factors. It was concluded that the interaction between reopening and connecting of natural fractures led to hydraulic fracture networks, which can be detected by pressure fluctuations. The fracture network is composed of multiple fractures, resembling an ellipsoid with the major axis different from the maximum horizontal stress direction. The treatment pressure will be substantially raised by both the great natural fracture density and high injection rates

Viscosity approximation methods for nonexpansive mappings and monotone mappings

AbstractViscosity approximation methods for nonexpansive mappings are studied. Consider the iteration process {xn}, where x0∈C is arbitrary and xn+1=αnf(xn)+(1−αn)SPC(xn−λnAxn), f is a contraction on C, S is a nonexpansive self-mapping of a closed convex subset C of a Hilbert space H. It is shown that {xn} converges strongly to a common element of the set of fixed points of nonexpansive mapping and the set of solutions of the variational inequality for an inverse strongly-monotone mapping which solves some variational inequality

Attitudes, practices and information needs regarding novel influenza A (H7N9) among employees of food production and operation in Guangzhou, Southern China: a cross-sectional study

BACKGROUND: As of 30 May 2013, 132 human infections with avian influenza A (H7N9) had been reported in 10 Chinese cities. On 17 May 2013, because a chicken infection with H7 subtype avian influenza virus was detected in Guanzhou, Guangzhou became the 11th city to conduct emergency response operations. The goal of this study was to identify attitudes, practices and information needs among employees of food production and operation in Guangzhou. METHODS: A cross-sectional survey of face-to-face interviews was used during 17–24 June 2013. All adults seeking health examination in Guangzhou Center for Disease Control and Prevention who had lived in Guangzhou for at least 3 months, were engaged in food production and operation, and agreed to participate were interviewed. RESULTS: Of 1,450 participants, 69.72% worried about being infected with the A/H7N9 and 74.41% stated that they had searched for information about A/H7N9. The internet (76.92%), television (67.56%), and newspapers (56.26%) were the main methods of obtaining information; the use of these methods differed significantly by various demographic variables (P < 0.05). More than one-fifth of participants complained that the information was not timely enough (20.28%) and was intentionally concealed by the government (20.76%). Nearly one-third (32.35%) did not believe that the government could control the A/H7N9 epidemic. Most participants (80.76%) reported washing hands more frequently than before, while over one-third (37.17%) stated no longer buying poultry. A total of 84.00% indicated a willingness to receive an A/H7N9 vaccine, and the primary reason for not being willing was concern about safety (58.19%). A history of influenza vaccination and worry about being infected with the A/H7N9 were significantly associated with intention to receive an A/H7N9 vaccine (P < 0.05). CONCLUSIONS: Our findings provide insight into the attitudes and practices of employees of food production and operation 3 months after the first human A/H7N9 case reported in China, and 1 month after infected chickens were identified in Guangzhou. Distrust in the health department should be addressed, and more effort should be made to improve compliance of proper preventive measures to reduce panic among the public. The information needs should be taken into account in the next step of health education

Paleoenvironmental change in the middle Okinawa Trough since the last deglaciation : evidence from the sedimentation rate and planktonic foraminiferal record

Author Posting. © The Authors, 2006. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Palaeogeography, Palaeoclimatology, Palaeoecology 243 (2007): 378-393, doi:10.1016/j.palaeo.2006.08.016.Well-dated, high-resolution records of planktonic foraminifera and oxygen isotopes from two sediment cores, A7 and E017, in the middle Okinawa Trough reveal strong and rapid millennial-scale climate changes since ~18 to 17 thousand years before present (kyr B.P.). Sedimentation rate shows a sudden drop at ~11.2 cal. kyr B.P. due to a rapid rise of sea-level after the Younger Dryas (YD) and consequently submergence of the large continental shelf on the East China Sea (ECS) and the retreat of the estuary providing sediment to the basin. During the last deglaciation, the relative abundance of warm and cold species of planktonic foraminifera fluctuates strongly, consistent with the timing of sea surface temperature (SST) variations determined from Mg/Ca measurements of planktonic foraminifera from one of the two cores. These fluctuations are coeval with climate variation recorded in the Greenland ice cores and North Atlantic sediments, namely Heinrich event 1 (H1), Bølling-Allerød (B/A) and YD events. At about 9.4 kyr B.P., a sudden change in the relative abundance of shallow to deep planktonic species probably indicates a sudden strengthening of the Kuroshio Current in the Okinawa Trough, which was synchronous with a rapid sea-level rise at 9.5-9.2 kyr B.P. in the ECS, Yellow Sea (YS) and South China Sea (SCS). The abundance of planktonic foraminiferal species, together with Mg/Ca based SST, exhibits millennial-scale oscillations during the Holocene, with 7 cold events (at about 1.7, 2.3-4.6, 6.2, 7.3, 8.2, 9.6, 10.6 cal. kyr BP) superimposed on a Holocene warming trend. This Holocene trend, together with centennial-scale SST variations superimposed on the last deglacial trend, suggests that both high and low latitude influences affected the climatology of the Okinawa Trough.This study was supported by the National Natural Science Foundation of China (Grant Nos. 40206007, 40106006, 90211022 and 40506027), the Chinese Academy of Sciences innovation program (KZCX3-SW-220), and the NSF (OCE05-29600 to DWO)

Microstructure and Oxidation Resistance of a Si Doped Platinum Modified Aluminide Coating Deposited on a Single Crystal Superalloy

A Si doped Pt modified aluminide coating was prepared by electroplating and the chemical vapour deposition method. The microstructure and oxidation resistance of the coating were studied, with a single Pt modified aluminide coating as a reference. The results showed that the Si doped Pt modified aluminide coating consisted of singular &beta;-(Ni, Pt)Al phase, and no PtAl2 phase was detected, which might be due to the fact that the addition of Si retarded the formation of PtAl2 phase in the outer layer. Si was dissolved in the &beta;-(Ni, Pt)Al phase in the outer layer and might form silicide with refractory elements in the inter-diffusion zone. The Si doped Pt modified aluminide coating possesses a better oxidation resistance than the Pt modified aluminide coating since Si could promote the formation of &alpha;-Al2O3 and inhibit the diffusion of the refractory elements, reducing the formation of detrimental volatile phase

Sediment source-to-sink processes of the southeastern Indian Ocean during the Late Eocene-Oligocene and their potential significance for paleoclimate

Understanding the paleoclimate responses in Southern Ocean and its surrounding land can help us to better explore the major climate transition mechanisms in geological history and predict the response ofthe earth system to abrupt climate changes in the future, while, there is still a lack of research on the paleoclimatere sponse of the surrounding land in Southern Ocean.Based on the age framework, major, traceand rare earth element compositions of the deep-sea sediments at Site U1516 of the International Ocean Discovery Program (IODP) 369, we determined that the sediments were mainly from the southwest continent of Australia, and then reconstructed the chemical weathering history of the source area on the tectonic time scale.In addition, we combined with the previous research results to discuss the paleoclimate evolution of continents surrounding Southern Ocean during the Late Eocene-Oligocene climate transition period and its response toglobal climate changes and regional paleogeographic changes.During the Eocene-Oligocene transition (e.g., 34.1 to 33.6 Ma and 31.3 to 29.8 Ma), the paleoclimate in the source area was mainly controlled by the significant changes in the paleogeographic pattern of the adjacent area, which was characterized by the climate conditions tending to bedry and cold and the decrease of chemical weathering intensity on the land surface.During the period of 33.6 to 31.3 Ma and 29.8 to 25.2 Ma, the palaeoclimate of the source area mainly responded to global climate changes.In theformer stage, the paleoclimate changed from dry and cold to wet and hot, the intensity of chemical weathering on the land surface increased correspondingly; In the latter stage, the climate maintained in a relatively stable dry and cold state, the intensity of chemical weathering on the land surface is also weak

Synthesis and spectroscopic investigation of fluorescent compounds containing bis-pyrazole ring

75-87A series of novel fluorescent compounds containing bis-pyrazole ring have been synthesized using 1-aryl-3-methylpyrazol-5-ones and 1-aryl-3,5-dimethylpyrazol-4-carbaldehydes as the starting materials. The synthesized compounds have been characterized by means of 1H NMR, IR, mass spectrometry and elemental analysis, and their ultraviolet–visible light (UV-Vis) absorption behavior and fluorescent properties have also been measured. At the same time, the molecular structure of compound B1 has been determined by single crystal X-ray diffraction. Moreover, the effect of acetic acid on the spectroscopic properties of the synthesized products has been examined using compounds A5 and B1 as examples. It has been found that all synthetic fluorescent compounds show two remarkable absorption peaks in a wavelength range of 250-254 nm and 360-380 nm; and their maximum emission peaks emerge around 323 nm. Besides, acetic acid leads to changes in the acidity of the medium thereby influencing the UV–Vis absorption spectra and fluorescent spectra of the synthesized compounds

Structure and Properties of Arc Ion Plating Deposited AlCrSiN Coatings Controlled by Pulsed Bias Voltage

AlCrSiN coatings are promising protective candidates for cutting and forming tools. During the coating deposition process, the microstructure and properties of the coatings were dramatically affected by bias voltages. To further optimize and enhance the AlCrSiN coating, a series of coatings were deposited at different pulse bias voltages using arc ion plating technology. By virtue of scanning electron microscopy, X-ray diffraction, scratch method, OCP, EIS, and other analytical methods, the effects of the pulse bias voltage on the crystal structure, microstructure, and mechanical, tribological, and electrochemical properties of the AlCrSiN coatings were analyzed. The study revealed that the pulse bias voltage exerted a slight influence on the aluminum and nitrogen content of the coatings. As the pulse bias voltage increased, the hardness, critical load, and tribological performance of the AlCrSiN coatings first increased gradually, and then were impaired slightly. When the pulse bias voltage was −100 V, the resulting AlCrSiN coating exhibited the densest structure, the highest hardness, the strongest adhesion, and the best wear resistance. In this case, the coating hardness and critical load reached 2668 HV and 72.7 N, respectively. The friction coefficient and wear rate were 0.35 and 1.02 × 10−3 μm3/N·μm, respectively. Simultaneously, the AlCrSiN coating demonstrated exceptional corrosion resistance in 3.5 wt.% NaCl solutions, surpassing uncoated 304 steel by 3~4 times