bluuebunny/crossref_metadata_2025 huggingface dataset:
Opioid Requirement following Arthroscopic Knee Surgery: Are There Predictive Factors Associated with Long-Term Use
Authors: Glogovac Georgina , Kennedy Mark , Parman Michael D. , Bowers Katherine A. , Colosimo Angelo J. , Grawe Brian M.
Published: November 2019

The purpose of this study is to identify patterns of postoperative narcotic use and determine the impact of psychosocial and perioperative factors on postoperative opioid consumption following arthroscopic knee surgery. Fifty consecutive patients undergoing arthroscopic knee surgery were prospectively enrolled. Patients were contacted via telephone at 1 week postoperatively to report their pain level and opioid consumption. The patient was contacted again at 2 weeks, 4 weeks, and 90 days as necessary until opioid cessation, at which time the patient's plan for unused pills was inquired. Opioid consumption was compared using t-tests and one-way analysis of variance for demographic and surgical factors. Linear regression was used to determine whether the Pain Catastrophizing Scale (PCS), Resilience Scale (RS-11), International Knee Documentation Committee questionnaire, or patient-reported pain at 1 week predicted higher opioid consumption. The average morphine equivalent dose of opioid consumption was 142 mg. Sixty-four percent consumed less than 100 mg, and 68% discontinued opioid use by 1 week postoperatively. Seventy-four percent reported surplus pills, and 49% of those patients plans for pill disposal. Factors associated with higher consumption included undergoing a major procedure, having a regional anesthesia block, and higher area deprivation index score (p < 0.05). Higher PCS scores and reported average pain level at 1 week were predictive of higher opioid consumption (p < 0.05). In conclusion, a majority of patients undergoing outpatient knee surgery did not require the entirety of their narcotic prescription. The majority of patients consumed less than 100 mg of morphine equivalents and discontinued opioid use by 1 week postoperatively. Ligament reconstruction, living in an area with a higher index of deprivation, and higher score on the PCS were associated with greater opioid consumption. Overall, patient knowledge regarding opioid disposal was poor, and patients would likely benefit from additional education prior to surgery.
2.3 Dual Catalysis with Two Organocatalysts
Authors: Wang H.-Y. , Zhao G.
Published: November 2019

The field of asymmetric organocatalysis has attracted the attention of chemists due to the environmentally benign conditions, particularly for the synthesis of chiral molecules, bioactive compounds, natural products, and drugs. Besides the conventional approaches using a single organocatalyst in asymmetric reactions, dual catalysis with two organocatalysts has emerged as an important strategy for resolving existing challenging problems, including the synthesis of complex molecules, improvement of enantioselectivities, and the development of new catalytic mechanisms. In this review, selected recent examples of the combination of two organocatalysts are covered in detail. Moreover, future perspectives are also described.
Femtosecond laser system based on thin rod Yb : YAG active elements with an output power of 110 W
Authors: Yang J. , Lee B. , Kim J.W. , Jeong B. , Sall E.G. , Chizhov S.A. , Heo D. , Yashin V.E. , Kim G.H.
Published: November 2019

A three-stage laser amplification system based on thin Yb : YAG rods with diode laser pumping is developed and fabricated. In this system, the average power of a continuous train of femtosecond pulses from a Yb : KGW master oscillator with a pulse repetition rate of 80 MHz and initial pulse duration of 128 fs was raised by a factor of 100 to above 100 W. Preliminarily chirped laser pulses provided compensation of dispersion in optical elements of the system and obtaining 580-fs output pulses. The longer duration of output pulses relates to spectrum narrowing in the amplifiers.
Spectral and temporal dynamics of ultrashort pulses in a holmium-doped fibre amplifier
Authors: Filatova S.A. , Kamynin V.A. , Zhluktova I.V. , Trikshev A.I. , Arutyunyan N.R. , Rybin M.G. , Obraztsova E.D. , Batov D.T. , Voropaev V.S. , Tsvetkov V.B.
Published: November 2019

We have optimised a hybrid mode-locked holmium-doped fibre laser and a holmium-doped fibre amplifier for obtaining stable pulses as short as possible. Temporal and spectral characteristics of pulsed light have been measured as functions of pump power. Lasing has been achieved in the wavelength range 2066 – 2068 nm, with a full width at half maximum of the emission spectrum from 3 to 4 nm. The pulse duration does not exceed 1 ps and the pulse energy ranges from 0.2 to 0.5 nJ. To raise the pulse energy, holmium-doped fibre amplifiers based on two types of active fibre have been used. We have demonstrated a decrease in the width of the central part of the pulse autocorrelation function and considerable broadening of the spectrum of the pulses. The maximum average power at the amplifier output exceeds 200 mW.
Design principles for modern fibre-optic communication lines
Authors: Konyshev V.A. , Nanii O.E. , Novikov A.G. , Treshchikov V.N. , Ubaydullaev R.R.
Published: November 2019

We discuss the design issues and characteristics of coherent fibre-optic communication networks taking into account the many physical effects that simultaneously influence signal propagation. Algorithms and easy-to-use ‘engineering’ techniques are proposed that allow network performance to be predicted and the design to be significantly simplified.
Defining resilience in pasture-based dairy-farm systems in temperate regions
Authors: Horan B. , Roche J. R.
Published: November 2019

The sustainable intensification of pasture-based food-production systems provides an opportunity to align the ever-increasing global demand for food with the necessity for environmentally efficient ruminant production. Biophysically and financially resilient grazing systems are designed to harvest a large amount of the pasture grown directly by the cow, while minimising the requirement for machinery and housing, and exposure to feed prices. This is primarily achieved by matching the feed demand of the herd with the annual pasture supply profile (i.e. seasonal milk production). Ideally, the entire herd is calved before pasture growth equals herd demand; breeding and drying-off policies facilitate this. The type of cow is also important; she must be highly fertile and have good grazing-behaviour characteristics. Pasture species are chosen to best suit the predominant climate, and pasture management aims to maximise the production and utilisation of chosen species. Purchased supplementary feeds support biophysical resilience and can be successfully incorporated into grazing systems, if stocking rate (SR) is increased to achieve high pasture utilisation. However, industry databases indicate that, on average, profitability declines with increasing purchased supplementary-feed usage, because of reduced pasture utilisation and lower than expected marginal milk-production responses. In the present paper, we outline the characteristics of resilient pasture-based dairy systems in the context of the necessity for the sustainable intensification of global food production.
The nanometre limits of ballistic and diffusive hot-hole mediated nonlocal molecular manipulation
Authors: Etheridge H G , Rusimova K R , Sloan P A
Published: November 2019

We report an experimental investigation into the surface-specific and experimental limits of the range of STM induced nonlocal molecular manipulation. We measure the spot-size of the nonlocal manipulation of bromobenzene molecules on the Si(111)-7 × 7 surface at room temperature at two voltages and for a wide range of charge-injection times (number of hot charge-carriers) from 1 s up to 500 s. The results conform to an initially ballistic, 6–10 nm, and then hot-hole diffusive, 10–30 nm, transport away from the localised injection site. This work gives further confirmation that nonlocal molecular manipulation by STM directly reveals the ultrafast transport properties of hot-charge carriers at surfaces.
Enhanced optical squeezing from quasi-bound states in the continuum and Fano resonances without nonlinearity
Authors: Li Zhixin , Zhang Xiangdong
Published: November 2019

To achieve a high degree of quantum noise squeezing, nonlinear optical interaction process is often employed. Here, we propose to utilize quasi-bound states in the continuum (quasi-BICs) and Fano resonances to enhance optical squeezing without nonlinearity. The theory of quantization for electromagnetic fields in the periodic nanostructure with dispersion and absorption has been developed by means of the Green’s function technique with the plane wave expansion method. The quasi-BICs and Fano resonances of radiation modes are realized by designing the photonic crystal slab structure. Based on these quasi-BICs and Fano resonances, we demonstrate that strong squeezed states can be realized by using the balanced homodyne detection scheme. The squeezing degree can be improved by more than 14 times when a weak squeezed states passes through the structure with quasi-BICs and Fano resonances. The advantage of this method is that it is not only efficient but also easy to implement because the nonlinear optical processes are not employed, which is very beneficial for the quantum information processing and precision metrology.
An attractiveness-based model for human mobility in all spatial ranges
Authors: Zhou Jianfeng , Fan Zhong-yan , Ng Kai-Tat , Tang Wallace K S
Published: November 2019

In the past decade, various aspects of human mobility, from individual to population levels in both spatial and time scales, have been studied. However, existing human mobility models still fail to describe activities in all spatial ranges, while in particular, local activities like self-loop fluxes are generally ignored. Moreover, the regional attractiveness, a basic but useful concept in mobility model design, remains difficult to be quantified due to its intricacies. To resolve these two fundamental issues, we introduce a trip competition mechanism to empower a mobility model to estimate population fluxes in all spatial ranges. The model includes attraction scores of regions in concern, obtained via optimizing the working population distributions. Its capability of predicting a variety of mobility patterns is verified by empirical data from three different countries, and its accuracy outperforms those of existing models. The quantified attractiveness is also found to be highly correlated with common socioeconomic indicators, and is able to act as a distinct metric to characterize a region.
Relative phase effect of nonsequential double ionization in Ar by two-color elliptically polarized laser field*
Authors: Chen Jia-He , Xu Tong-Tong , Han Tao , Sun Yue , Xu Qing-Yun , Liu Xue-Shen
Published: November 2019

We investigated the nonsequential double ionization (NSDI) in Ar by two-color elliptically polarized laser field with a three-dimensional (3D) classical ensemble method. We study the relative phase effect of NSDI and distinguish two particular recollision channels in NSDI, which are recollision–impact ionization (RII) and recollision-induced excitation with subsequent ionization (RESI), according to the delay-time between the recollision and the final double ionization. The numerical results indicate that the ion momentum distribution is changed and the triangle structure is more obvious with the decrease of the relative phase. We also demonstrate that the RESI process always dominates in the whole double ionization process and the ratio of RESI and RII channels can be influenced by the relative phase.
Neutron-based characterization techniques for lithium-ion battery research
Authors: Zhao Enyue , Zhang Zhi-Gang , Li Xiyang , He Lunhua , Yu Xiqian , Li Hong , Wang Fangwei
Published: November 2019

During the past decades, Li-ion batteries have been one of the most important energy storage devices. Large-scale energy storage requires Li-ion batteries which possess high energy density, low cost, and high safety. Other than advanced battery materials, in-depth understanding of the intrinsic mechanism correlated with cell reaction is also essential for the development of high-performance Li-ion battery. Advanced characterization techniques, especially neutron-based techniques, have greatly promoted Li-ion battery researches. In this review, the characteristics or capabilities of various neutron-based characterization techniques, including elastic neutron scattering, quasi-elastic neutron scattering, neutron imaging, and inelastic neutron scattering, for the related Li-ion-battery researches are summarized. The design of in-situ/operando environment is also discussed. The comprehensive survey on neutron-based characterizations for mechanism understanding will provide guidance for the further study of high-performance Li-ion batteries.
Research on the Development Roadmap of Wind Power Industry Under High Renewable Energy Penetration
Authors: Li Lingyun , Gan Jingshuang , Guo Xinju
Published: November 2019

Renewable energy with high resource potential and less environmental pollution are receiving more and more attention. Wind power is a relatively mature energy source in renewable energy. As the internal and external uncertainty of the wind power industry chain are various and complex, it is urgent to clarify the uncertainty and relationship. Through big data technique, main uncertainty impacted on the development of the wind power industry chain is identified. And an interpretative structural model is established to analyze the hierarchy structure to the uncertainty. The results can provide valuable reference to identify and solve the key problems in the development roadmap of wind power industry, as well as to make scientific decision.
Experimental Study on Recovery of Cyanide Tailings Slurry by Membrane Separation in a Gold Mine
Authors: Liu Yanli , Liu Fengbiao , Zheng Xi , Yang Xiaosong , Wang Fang
Published: November 2019

In view of the difficulty in recovering valuable metals and cyanides from cyanide tailings pulp in gold mines, the laboratory exploratory test of recovering gold and silver from the tailings pulp produced by a CIP process was carried out by using the technology of “solid-liquid separation + membrane separation and purification + adsorption and recovery of gold and silver by activated carbon”. The results showed that the cyanide tailings slurry was separated by solid-liquid in the laboratory and stabilized by chemicals, and the dry slag was identified as a general solid waste according to the results of the identification standard for hazardous waste leaching toxicity GB5085.3-2007. The screened reverse osmosis membrane test showed that 95% of the permeate water recovery rate were obtained. The concentration of cyanide in membrane concentrate water reached 807.9 mg/L, the concentration of copper, gold and silver reached 0.43 mg/L and 3.91 mg/L respectively after being concentrated from below the detection limit, and the concentration was 19.9, 14.3 and 18.6 times respectively. The adsorption test of membrane concentrate water by activated carbon showed that gold, silver and copper were absorbed in membrane concentrated water, the adsorption rates reached 99.76%, 96.16% and 9.09% respectively, which facilitated the subsequent selective recovery of gold and silver. The recovery of valuable metals and cyanide from cyanide tailings slurry by the process of “solid-liquid separation + membrane separation and purification + adsorption and recovery of gold and silver by activated carbon” had a good effect.
Method for generating high-precision calibration force for low thrust measurement
Authors: Chen Ji , Zhou Weijing , Hong Yanji
Published: November 2019

The micro-thrust measurement system plays an important role in the development of micro-nano satellites. The method of obtaining high-precision calibration force is one of the key technologies of the micro-thrust measurement system. The smaller the calibration force error, the higher the calibration accuracy of the system parameters, and the higher the measurement accuracy of the measurement system. In this paper, a high-precision calibration force generation method is obtained through experiments and experiments using magnets and coils.
Study on the efficacy of anaerobic biological treatment of industrial wastewater
Authors: Chang Min
Published: November 2019

In this research, we examined the internal circulation (IC) reactor performance on fur processing wastewater and explored the optimum operation parameters of IC reactor with high concentration volatile fatty acids (VFA) by a 60d field test in middle temprature. The results showed that the wastewater can be adapted to the IC reactor and start rapidly. In steady operation stage, when the influent CODcr concentration stabilises at under 3000 mg·L-1 and the acidibility is at around 45%, there is no apparent VFA accumulation and the effluent CODcr removal rate remained stable at about 55%. When the concentration of influent CODcr exceeds 3000 mg·L-1 and fluctuations obviously, the average removal rate of CODcr is about 50%. The average removal rate of grease is 61.3%, and the HRT is 6 h. Compared with the existing hydrolysis acidification and aerobic treatment, IC reactor treatment has improved the efficiency of VFA degradation significantly, which indicates that IC reactor has great engineering applicability for treating fur processing wastewater.
Advanced Oxidation Technology for Refractory Organic Compounds in Wastewater
Authors: Shi Runzhe
Published: November 2019

As a relatively important task in the current industrialization development, wastewater treatment has become increasingly demanding in the context of China’s current rapid industrialization. In order to improve the quality of industrial wastewater treatment, it is necessary to clarify the relevant treatment technologies according to the requirements of the treatment process. Meanwhile, scientific treatment methods should also be combined with the requirements in the wastewater treatment technology, especially for the treatment of refractory organic compounds in wastewater. In other words the quality of wastewater treatment can be improved only by scientific treatment of refractory substances in wastewater. Therefore, this paper analyzes the advanced oxidation technology for degrading refractory organic compounds in wastewater, with the aim to clarify the treatment of refractory organics in wastewater and thenimprove wastewater treatment quality.
Parameters Tuning of Photovoltaic Power Generation System with Static Synchronous Compensator Based on Chaos Orthogonal Particle Swarm Optimization
Authors: He Weiguo , Zhang Xiangwen , Wei Wei , Shi Linjun
Published: November 2019

China is a country rich in solar energy resources, with good natural conditions for the utilization of solar energy. At present, the main application mode of photovoltaic power generation system is grid-connected photovoltaic power generation. In order to maintain the voltage stability of the common connection point (PCC), STATCOM is mainly added to the PCC of photovoltaic power station. It can be regarded that the photovoltaic system and STATCOM constitute a whole and are integrated into the grid, and the unified coordination and optimization of the overall control system becomes particularly important. In this paper, the parameter tuning strategy of PI controller for photovoltaic grid-connected system with STATCOM is studied. Taking the optimal overall performance of DC capacitor voltage and PCC point voltage of photovoltaic inverters as the optimization objective, chaotic orthogonal particle swarm optimization algorithm is used to optimize the parameters of PI controller of the system, and simulation is carried out under the condition of voltage variation to verify the effectiveness of the optimization strategy.
Graphene based non-noble metal catalyst for oxygen reduction reaction
Authors: Chuai Yunhan
Published: November 2019

The current noble-metal Pt based oxygen reduction reaction electrocatalysts suffer from high cost and poor operational durability. It is an urgent demand to developing alternative catalysts that are cost effective, readily available, and have the comparable catalytic activity than Pt for oxygen reduction reaction. Recently, graphene-based non-noble metal catalysts have been investigated and shown desirable activity and stability toward oxygen reduction reaction. Here, we offer a timely review paper to illustrate the recent progresses of graphene based electrocatalyst, including heteroatom doped graphene and graphene-inorganic nanoparticle composite. We hope this article can provide a guideline for rational design of highly active graphene-based non-noble metal catalysts toward oxygen reduction reaction.
Phase split of oil-water two phase flow at double-layer T-junctions pipes
Authors: Yang Lele , Wang Jing , Ma Yong , Zou Li
Published: November 2019

Offshore oil and gas production systems are in urgent need of a more compact, high-efficient oil-water separator. T-junction pipes are a potential solution to the need. Combining dynamic separation principle of T-junctions pipes with shallow pond theory, this paper presents a novel design of double-layer T-junctions pipes to realize high-efficient oil-water separation. The separation system consisted of upper and lower double-layer pipes that are connected by two vertical pipes. There exists an axially floating oil pipe along the top of the upper outer pipe. This design makes the Reynolds number decrease, which is beneficial to the formation of oil-water stratified flow. The slender seam at the bottom of inner pipe reduces the turbulence intensity, thus avoiding remixing oil with water. The influence of mixture velocity, oil content, water superficial velocity, oil superficial velocity, and inlet flow pattern on the phase split of oil-water two phase flow at double-layer T-junctions pipes has been investigated. Experimental results showed that the separation performance was less affected by the inlet oil content than by the inlet mixture velocity. Additionally, the phase split in the separation system was very sensitive to the inlet flow pattern. For separated flow pattern, oil-water can be well separated. But for dispersed flow pattern, the oil-water separation efficiency was low. Besides, the using of floating oil pipe can increase the system separation efficiency.
Estimation of Three-Dimensional Solubility Parameters of DM-700 Polyester Resin by Turbidity Titration
Authors: Liu Qiang , Shi Xiaoqin , Lu Yanqiu , Dong Liming
Published: November 2019

According to the method of turbidity titration and 63 cloud point data minimum volume closure ellipsoid fitting, the solubility parameter of polyester resin DM-700 was determined to be 22.84(MPa)1/2, and the three-dimensional solubility parameter was (δd=17.15 (MPa)1/2; δp=9.97(MPa)1/2; δH=11.32(MPa)1/2). This value is close to the result calculated by the group contribution method (22.68(MPa)1/2), which further proves that the method is accurate and reliable.
Analysis on Key Problems of Winter Operation in Alpine-cold Open-pit Mine
Authors: Bao Haiming
Published: November 2019

Through the analysis of winter operation problems in the alpine-cold open pit mine in Mengdong area, the technical and economic feasibility of adopting advanced peeling and winter peeling scheme is demonstrated. For the open-pit mining and transportation equipment in the alpine-cold region, the solutions for the scooping and sticking materials, the freezing of the brake circuit, and the sticking of the compartments are often proposed in winter operations. The anti-freeze system of the belt conveyor is composed of the cold resistant tape, the cleaning device, the antifreeze film, the heating device and the anti-freeze roller. Some safety production organization measures for blasting operations, mining operations, and semi-continuous systems in winter construction operations were proposed. It can effectively help the open pit mines in the alpine-cold regions to reduce equipment failures and ensure efficient operation in winter safety production.
Modeling pressure-sensitive effect of shale gas wells based on history matching
Authors: Li Zhanke , Shi Anfeng , Wang Xiaohong , Liu Zhifeng , Liu Zhifan
Published: November 2019

Based on the measured data of gas production and backflow flux in Sichuan Province of China, pressure-sensitive effect is studied based on history matching in this article. When the shale gas development is on-going, the reservoir pressure declines and micro-fracture network may be partially closed in the stimulated reservoir volume (SRV). The closure of micro-fracture network not only leads to the decrease of absolute permeability, but also to the variation of relative permeability curve. The pressure-sensitive effect coefficient of relative permeability is introduced in this article to characterize this effect.
Research of Coupled Coordination Degree of Water Resources, Energy and Food System in Henan Province From 2008 to 2018
Authors: Yan Xin , Feng Yuanlin , Ye Jianing
Published: November 2019

With decrease of water resources and increase of energy demand in social life, uncertainty of food supply, which becomes severe, increase necessity of initiating a study of the degree of the coupled coordination among these three subsystems. Taking Henan Province as the research object, this paper calculates the coupled coordination degree in Henan Province from 2008 to 2018 by referring the coupling model. The results show that the degree of the coupled coordination of these three is divided by 2013, showing high coupling and extreme coupling state.
Analysis on the effect of prolonged injection of oil layer in the Gao 2 Formation of La 8-182 well area in Lamadian Oilfield
Authors: Li Dandan
Published: November 2019

At the end of 2012, the three types of oil layers completed the design of the polymer dosage. Since the water content did not rise and the concentration of the polymerization was low, the injection was prolonged from January of the 13th. The extension of the injection phase still has a strong injection capacity, and the water-bearing initial stage is slowly and slowly recovered. In this paper, the characteristics of water cuts in the extended injection phase of the test area are analyzed in combination with different water body water change laws and comprehensive adjustment methods, in order to optimize the three types of oil stratification. The design of the drive scheme provides a basis for accurately predicting the ultimate improvement of the recovery rate of the three types of oil layers.
Characteristics of lead smelting fume and its potential treatment technology
Authors: Wang Fang , Li Mingjun , Liu Yanli
Published: November 2019

Fine particles emitted from lead smelting furnaces contains a variety of heavy metals and oxidized condensates, which are characterized by complex composition and great harm. In this paper, dust samples from lead smelter were collected, and particle size analysis, composition analysis, phase analysis and specific resistance test were carried out in the laboratory. According to the properties of the lead dust, the experiment flow of electric coagulation was designed to verify the effect of using electric coagulation to condense fine particles in lead dust.
Study on Spill Risk Emergency Response Framework System in the Offshore Oil Development—Taking Chengdao oil field as an example
Authors: Ma Long , Zhang Liting , Meng Tao , Liu Dachuan
Published: November 2019

Taking Chengdao oil field as an example, the establishment of spill risk emergency response framework system was discussed combined with the development of offshore oil spill risk. Based on the identification source of spill risk and the impact on the marine environment, we attempted to analyze the problem from the six aspects, including construction of the oil spill surveillance and monitoring capacities, construction of the warning capacities, construction of the command & organization & coordination mechanism, construction of the site disposal capacities, construction of the emergency guarantee linkage mechanism and construction of the environmental damage assessment. And finally, some guide was hoped to provide in the aspects of promoting the safety of offshore oil production, reducing the accident rate and improving the performance of emergency response.
Study on Process Technology of Raw Material Water Pretreatment for Extracting Bromine
Authors: Zhang Yanan , Song Da , Yao Ying , Hao Xiaocui , Liu Wei , Li Tao , Zhang Qi
Published: November 2019

In view of the characteristics of different bromine raw materials such as seawater, desalinated concentrated seawater, and cultured salt brine, the raw material liquid is carried out by examining physical and chemical indicators such as temperature, turbidity, pH, Br-, suspended solids, COD, residual chlorine and chemical components. Purification, acidification, oxidation and other pretreatment processes are studied to form a pretreatment process suitable for different bromine feedstocks. Satisfy the influent water quality requirements of different bromine extraction methods, form a mature pretreatment process, provide important support for the related vertical issues in the field of bromine and the application of horizontal development projects such as feasibility study and design, and help to achieve desalination projects and The scientific combination of bromine engineering.
Study on Gas Control Technology of Large Diameter Directional Borehole
Authors: Xu Zunyu
Published: November 2019

With the development and extension of the mine, the mine gas, water, ground pressure and fire disasters further deteriorated, seriously affecting the safe and efficient production of the mine. Combining with the actual geological conditions, this paper analyses the feasibility of large diameter directional drilling construction on the roof of working face, calculates the construction horizon of directional drilling, and through field investigation, analyses the construction effect, extraction effect and cost comparison. Comprehensive comparison shows that large diameter directional drilling on roof can shorten the construction period of gas control engineering in working face, alleviate the situation of tense replacement of working face, reduce the amount of gas control roadway engineering, and save the cost of gas control engineering.
Experimental investigation and modelling of the gas jet in liquid cross flow
Authors: Dong Ping , Gong Shaofeng , Lu Bingju , Cheng Dong
Published: November 2019

In the present study, the development of a submerged gas jet subjected to liquid cross flow is experimentally and theoretically investigated to evaluate the effects of the cross flow. Experimentally, a submerged gas jet is injected into the liquid flow with different cross velocities (0.35 m/s, 0.7 m/s, 1.0 m/s, 1.5 m/s, 2.0 m/s) created by the newly designed experimental facility. The jet morphologies are captured by shadow photography and the images are processed to extract the parameters of the gas/liquid interface. An integral model including the jet entrainment is proposed to predict the jet evolution. It turns out that the integral model is able to predict the jet development accurately, and an overall good agreement was obtained between the theoretical and experimental results over a range of cross flow velocities.
Study on the Development Effect and Well Pattern Adaptability of Eastern Xing No.1 - No.2 Area
Authors: Wang Weixue , Xia Lianjing , Fan Hailin , Zhu Huanlai , Wei Huabin
Published: November 2019

The eastern part of Xing No.1 ∼ No.2 area is located in the northeast of Xingbei development area, Daqing oilfield. This block has the “double height” feature of high degree of production and high comprehensive water cut. Because the block has produced oil for a class of reservoirs for three times, the overall production degree is relatively high. In order to effectively improve the block water flooding development effect, this paper adopts several evaluation indexes to study the block development effect and well pattern adaptability.
Experimental analysis and logging evaluation of in-situ stress of mud shale reservoir-- Taking the deep shale gas reservoir of Longmaxi Formation in western Chongqing as an example
Authors: Mao Haiyan , Luo Tongtong , Lai Fuqiang , Zhang Guotong , Zhong Lulu
Published: November 2019

The complex structural conditions of marine shale in Western Chongqing area lead to the problems of insufficient understanding of pore structure, unclear direction of in-situ stress and poor fracturing effect, which lead to the difficulty of shale gas development. Based on the experimental study and logging data, the calculation model of in-situ stress is established. Finally, the influencing factors of in-situ stress are analyzed. The results show that the distribution of three-direction stress in the target interval is σH>σv>σh, and the experimental and logging results are consistent. As a whole, the in-situ stress tends to decrease with the increase of depth, with little fluctuation and good continuity. The fragility characteristics of the reservoir are relatively good, and it is easier to form various cracks that are widely developed.
Research on Deep Profile Control Technology of Water Flooding in Lamadian Oilfield
Authors: Liu Chunyan
Published: November 2019

After Daqing Lamadian Oilfield entered the stage of development of ultra-high water cut, the ineffective circulation of various oil layers was serious, which restricted the development benefit of oilfields. To this end, the research on deep profile control of water flooding is carried out, and the combination of polymer microsphere flexible diverting agent and bulk expanded particle slug is used to exert a slower blocking speed of polymer microspheres, and a certain resistance is established in the deep pores of the reservoir. To provide the main slug with aggregating residence time; to exert the superior advantage of flexible steering agent deformation and adhesion ability, to form a dynamic path-distributing mechanism in the deep cavity of the reservoir; to play the advantage of faster blocking speed of the bulk-expanding particles, to prevent the main section The plug was flushed by subsequent water injection. Through the multi-segment combination indoor core experiment, it is shown that the front section is filled with microspheres, the main section is filled with flexible agent, and the post-segment is filled with expanded particles, which can well block the invalid circulation part, improve the displacement effect and improve The recovery rate can reach 3.12 percentage points. On October 16, 2013, Daqing Lamadian Oilfield carried out a deep liquid flow steering test study on the 9-injection and 16-hole water-flooding group. The comprehensive water content of the affected oil wells decreased by 7.8 percentage points, and the cumulative oil increase was 5,435 tons. The rate is 2.7 percentage points, and the input-output ratio is 1:4.0, which has achieved better mine results.
Application of Well Test Interpretation in Oilfield Based on PDA Method in Tight Gas Reservoir
Authors: Du Peng
Published: November 2019

The reservoir characteristics of tight sandstone gas reservoirs are characterized by low porosity and low permeability, which brings difficulties to the conventional pressure recovery well test in oil fields. The lower porosity and permeability greatly extend the test time. Radial flow was not detected when the oil well was shut down for more than one month. The well test curve showed strong multi-solution characteristics and could not obtain accurate formation parameters. In this paper, based on the characteristics of tight gas reservoirs, the well test interpretation method (PDA method) is applied to the application of production data. A set of explanations for using the production data to explain tight gas wells and carrying out capacity evaluation and prediction are proposed. The interpretation of the production data of 1 is compared with the interpretation results of the pressure recovery test of the well. The two methods have good consistency, and the multiple interpretation methods can better reduce the multi-solution of the well test interpretation, and verify the PDA. The feasibility of the method applied on tight gas wells, and finally the correctness of the method was verified by the capacity prediction method.
Research on Optimized Penetration Ratio Fracturing Technology for Transition Zone
Authors: Zhang Chengling
Published: November 2019

The geological reserves of the Sazhong transition zone are 10046×104t, accounting for 12.5% of the Sazhong development zone. The effect of fracturing stimulation in this block is of great significance for the stable production of the Sazhong oilfield. The transition zone has the characteristics of low porosity, low permeability and low oil saturation. The crude oil has three high and one low characteristics: high viscosity, high wax content, high freezing point and low sulfur content. In the transition zone, due to poor physical properties of the oil layer, unbalanced formation pressure, high proportion of low-yield and low-efficiency wells, and energy replacement of thin oil layers, it is difficult to tap the potential of the production increase measures, and the effect of the measures is getting worse year by year. According to statistics, since the transition zone has 40 fractured oil wells since 2009, the fracturing process is general pressure and multi-crack, and the average pressure is 3 layers and 1 slit. The average average sand volume of single seam is 7.1m3, the average sand ratio is 25.7%, and the penetration ratio is only 14.1%. The average initial liquid increase after fracture is 20.4t, and the average initial daily oil increase is only 2.5t. Therefore, the study of transition zone fracturing technology can improve the overall development effect of the block, which is of great significance for the sustainable high yield and stable production of the Sazhong Oilfield.
Characteristics of Road Surface Temperature in Beijing Winter and its statistic forecasting models Based on the RMAPS Product
Authors: Dong Yan , Guo Wenli , Li Naijie , Zhang Hanbin , Min Jingjing
Published: November 2019

An analysis of the inter-diurnal variation of road surface temperature in the different weather conditions in Beijing winter is done, based on the data of the road stations from 2012 to 2017 and the outcomes from the numerical forecasting model, Rapid-refresh Multi-scale Analysis and Prediction System (RMAPS), which are constructed in this paper. First, the correlation coefficients between road surface temperature and the meteorological factors output by the RMPAS model are investigated. We used the stepwise regression model methods to build three kinds of types of statistical models for hourly road surface temperature in 24 h in winter. Then the best forecasting models are chosen to build for forecasting road minimum temperature in winter from A1027 road station selected. The results show that there exists a significant diurnal variation for the road surface temperature, suggesting that the road surface temperature is obviously different under the different kind of weather conditions. The road surface temperature is correlated with air temperature, atmospheric radiation, and sunshine duration. Compared to the type of statistical model with the only one factor for the road temperature of previous day, the type of regression model with meteorological elements of remarkable correlation inserted performs better in terms of the road surface temperature forecast accuracy by more than 25%, and the prediction error decreases by 1 °C.
Experimental Study on Influence of Dry Density on Soil-water Characteristic Curve of Hefei Expansive Soil
Authors: Chi Zecheng , Zeng Guanghui , Meng Zhaowei , Wu Song , Zhang Weipeng , Tian Ruogu
Published: November 2019

The soil-water characteristic curve is an important curve in the study of unsaturated soil mechanics. It plays an important role in improving theoretical analysis and numerical calculation in geotechnical engineering to find out the effect of initial dry density on SWCC. Based on the filter paper test, four soil-water characteristic curves of Hefei remolded expansive soil samples under different initial dry densities were determined. The influence of initial dry density on SWCC was systematically analyzed. The results show that: (1) In the w-s curve, the suction will increase with the decrease of moisture content, and SWCC will move to the upper right with the decrease of dry density. (2) In the ω-s curve, the influence of the dry density on SWCC decreases as the suction becomes larger. When the moisture content is less than 10%, the difference in dry density no longer affects the SWCC. (3) Part of the SWCC with moisture content below 10% can be measured only once, which has important guiding significance for improving the efficiency of SWCC test. (4) In the Sr-s curve, the suction will increases with the decrease of the saturation, and the increase of the dry density of the sample causes the move of SWCC to the upper right.
Study on Flow Field Characteristics in Deflecting Section of Shale Gas Horizontal Well
Authors: He Pei , Lu Zhaohui , Zhang Ye , Zhang Yi , Meng Chun
Published: November 2019

In order to study the characteristics of flow field at different deflecting sections of shale gas horizontal Wells, actual downhole string model is established to study the bottom-hole and annulus flow field characteristics by numerical simulation technology. The results show that the variation of deviation Angle has little influence on bottom hole and near bottom annulus flow field. When optimizing construction hydraulic parameters, the influence of the variation of inclined angle on bottom-hole flow field can be neglected. However, the distribution of annular velocity far away from the bottom hole is different, and the flow field characteristics of high inclined angle well are better than others, it is not easy to form cuttings bed during in construction. But more attention should be paid to problems of rock carrying in the low angle deflecting section of well. The research results can be used to guide the optimization of construction parameters and focus on the difficult problems in deflecting section of shale gas horizontal Wells.
Lessons Learned from Stimulation of Dibei Tight Gas Reservoir with Strong Heterogeneity in Tarim Basin
Authors: Fan Wentong , Wang Liao , Huang Longcang , Li Suzhen , Liu Jiangyu , Zhai Wen
Published: November 2019

The Dibei gas field is a naturally fractured tight sandstone gas reservoir in the Tarim Basin, West China. It is characterized by large depth (4600–5200 m), huge thickness (100–200 m), low abundance, low matrix permeability, high pressure (80–95 MPa), high temperature (140 – 150°C) and strong heterogeneity. Different stimulation techniques were applied to improve well production. For the wells with good development of natural fractures, matrix acidizing, acid fracturing or conventional hydraulic fracturing is used. For the wells with low fracture density and huge thickness, separate-layer acid-fracturing, massive separate-layer hybrid fracturing or composite diverting agent is applied to improve stimulation efficiency. The low-damage high-temperature weighted fracturing fluids are used to reduce the effect of reservoir sensitivity and the treatment pressure, and high-strength proppant is used at the same time to keep high fracture conductivity. Meanwhile, large-diameter fracturing string with 3-1/2″ and 4-1/2″ connections is used to decrease pump pressure and increase pump rate. The above technologies were applied in more than twenty treatments in seven wells, of which more than half witnessed production increase. The matrix acidizing or conventional hydraulic fracturing is well performed for the wells with natural fractures, but inefficient for the extremely tight gas wells. In Well A without fractures, the massive separate-layer hybrid fracturing was used. In the treatment, a total of 1,328 m3 fracturing fluid was used, with 50 m3 proppant; the pump rate was 8 m3/min and the maximum pump pressure was 92 MPa. Unfortunately, the post-frac production was not as expected, mainly due to the damage of killing well. In Well B with fractures, high gas production was achieved by acid fracturing, but the gas rate dropped from 258,000 m3 to 51,000 m3 after killing well, and the gas rate never recovered even by acid fracturing, hydraulic fracturing and relieving damage with methanol. The development of natural fractures is the key controlling factor for gas production. Well C, less than 800 m from well B, The development of natural fractures is quite different from Well B, and 98,000 m3 gas rate was acquired after hydraulic fracturing with more than 1,000 m3 low damage high-temperature weighted fracturing fluid and 30 m3 proppant. The development of natural fractures is the key controlling factor for gas production and killing well damage is the fatal blow to the gas production, so the stimulation techniques and working fluid system should be prudently optimized.
Remote Sensing Image Dehazing Algorithm Based on Wavelet Coefficient Weighting
Authors: Jin Jianglei , Yan Haowen
Published: November 2019

This paper introduces the principle of the defogging algorithm and the steps of the algorithm implementation. According to the simulated image and result, the data is recorded, and the wavelet coefficient weighting is applied to evaluate the effect of remote sensing image de-clouding. Compared with the homomorphic filtering algorithm and Retinex algorithm, the wavelet coefficient weighting is applied to the remote sensing image. The effect of cloud treatment is very good.
Mine Fire Prediction Based on WEKA Data Mining
Authors: Wang Xin , Hao Jian , Chen Jun , Cheng Weijia
Published: November 2019

Mine fires are prone to cause catastrophic accidents such as gas accidents and coal dust explosions in gas-exposed coal mines, which seriously threaten the safe production of mining enterprises. In order to effectively reduce the probability of gas explosion in mines, an accurate prediction of possible fire hazards in Linhua Coal Mine is made: collecting data on fire occurrence indicators; using Weka software on the basis of rough set theory, selecting SVM classifier, BP neural network and J48 decision tree to obtain the accuracy of the samples to be tested; analyzing the detailed accuracy, confusion matrix and node error rate, and obtain the optimal algorithm. On this basis, a mine fire predictive control model is proposed to determine and control the hazard grade of mine fire source and effectively reduce the probability of coal mine fire occurrence. The establishment of this model greatly ensures the safe production of gas outburst mine.
Evaluation Research on the Impacts of Coal Industry Development on Ecological Security in Inner Mongolia
Authors: Li Li , Chen Jiabin , Yan Dan
Published: November 2019

The paper uses PSR model to evaluate the ecological security situation from three dimensions of stress, state and response. The results show the level of economic development, social harmony and the realization of low-carbon ecological integrated Systems in Inner Mongolia is -0.03373, 0.053565, and 0.117664. The development degree, development continuity, development coordination degree and development effectiveness of low carbon ecological area construction in Inner Mongolia are 0.13361, 1.656154, 57.98879, 0.01741. The evaluation result of the sustainability of low carbon ecological development in Inner Mongolia is in the fourth level. The degree of development coordination and development effectiveness are judged at level five. Through the evaluation and grading results of low carbon ecological development in Inner Mongolia, we know that Inner Mongolia, as a coal resource-based region, is under great pressure to develop low-carbon ecology.