Experimental investigation on using CO_(2)/H_(2)O emulsion with high water cut in enhanced oil recovery

CO_(2) emulsions used for EOR have received a lot of interest because of its good performance on CO_(2)mobility reduction.However,most of them have been focusing on the high quality CO_(2) emulsion(high CO_(2) fraction),while CO_(2) emulsion with high water cut has been rarely researched.In this paper,we carried out a comprehensive experimental study of using high water cut CO_(2)/H_(2)O emulsion for enhancing oil recovery.Firstly,a nonionic surfactant,alkyl glycosides(APG),was selected to stabilize CO_(2)/H_(2)O emulsion,and the corresponding morphology and stability were evaluated with a transparent PVT cell.Subsequently,plugging capacity and apparent viscosity of CO_(2)/H_(2)O emulsion were measured systematically by a sand pack displacement apparatus connected with a 1.95-m long capillary tube.Furthermore,a high water cut(40 vol%) CO_(2)/H_(2)O emulsion was selected for flooding experiments in a long sand pack and a core sample,and the oil recovery,the rate of oil recovery,and the pressure gradients were analyzed.The results indicated that APG had a good performance on emulsifying and stabilizing CO_(2) emulsion.An inversion from H_(2)O/CO_(2) emulsion to CO_(2)/H_(2)O emulsion with the increase in water cut was confirmed.CO_(2)/H_(2)O emulsions with lower water cuts presented higher apparent viscosity,while the optimal plugging capacity of CO_(2)/H_(2)O emulsion occurred at a certain water cut.Eventually,the displacement using CO_(2)/H_(2)O emulsion provided 18.98% and 13.36% additional oil recovery than that using pure CO_(2) in long sand pack and core tests,respectively.This work may provide guidelines for EOR using CO_(2) emulsions with high water cut.

Enhanced nitrogen removal at low temperature with mixed anoxic/oxic process

Different hydraulic retention times(HRTs)were tested in a mixed anoxic/oxic(A/O)system at 5C and 10C to investigate the effects of HRT and carrier on nitrogen removal in wastewater at low temperatures.The results showed that the addition of the fillers improved the treatment effect of each index in the system.With an optimal HRT of 7.5 h at 5C,the removal efficiencies of NHþ4-N and total nitrogen(TN)reached 91.2%and 75.6%,respectively.With an HRT of 6 h at 10C,the removal efficiencies of NHþ4-N and TN were 96.7%and 82.9%,respectively.The results of high-throughput sequencing showed that the addition of the suspended carriers in the aerobic zone could improve the treatment efficiency of nitrogen at low temperatures.The microbial analysis indicated that the addition of the suspended carriers enhanced the enrichment of nitrogen removal bacteria.Nitrospira,Nitrotoga,and Nitrosomonas were found to be the bacteria responsible for nitrification,and their relative concentrations on the biofilm at 5C and 10C accounted for 98.11%,92.79%,and 69.98%of all biological samples,respectively.

Image enhancement with intensity transformation on embedding space

In recent times,an image enhancement approach,which learns the global transformation function using deep neural networks,has gained attention.However,many existing methods based on this approach have a limitation:their transformation functions are too simple to imitate complex colour transformations between low-quality images and manually retouched high-quality images.In order to address this limitation,a simple yet effective approach for image enhancement is proposed.The proposed algorithm based on the channel-wise intensity transformation is designed.However,this transformation is applied to the learnt embedding space instead of specific colour spaces and then return enhanced features to colours.To this end,the authors define the continuous intensity transformation(CIT)to describe the mapping between input and output intensities on the embedding space.Then,the enhancement network is developed,which produces multi-scale feature maps from input images,derives the set of transformation functions,and performs the CIT to obtain enhanced images.Extensive experiments on the MIT-Adobe 5K dataset demonstrate that the authors’approach improves the performance of conventional intensity transforms on colour space metrics.Specifically,the authors achieved a 3.8%improvement in peak signal-to-noise ratio,a 1.8%improvement in structual similarity index measure,and a 27.5%improvement in learned perceptual image patch similarity.Also,the authors’algorithm outperforms state-of-the-art alternatives on three image enhancement datasets:MIT-Adobe 5K,Low-Light,and Google HDRþ.

Experimental verification of nanonization enhanced solubility for poorly soluble optoelectronic molecules

Solubility enhancement has been a priority to overcome poor solubility with optoelectronic molecules for solution-processable devices. This study aims to obtain experimental data on the effect of particle sizes on the solubility properties of several typical optoelectronic molecules in organic solvents, including the solubility results of 1,3-bis(9-carbazolyl)benzene(m CP), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)ben zene(TPBi) and 2-(4-tert-butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole(PBD) in ethanol and acetonitrile,respectively. Nanoparticles of m CP, TPBi and PBD with sizes from dozens to several hundred nanometers were prepared by solvent antisolvent precipitation method and their solubility were determined by using isothermal saturation method. The saturation solubility of nanoparticles of three kinds of optoelectronic molecules exhibited increase of 12.9%-25.7% in comparison to the same raw materials in the form of microparticles. The experimental evidence indicates that nanonization technology is a feasible way to make optoelectronic molecules dissolve in liquids with enhanced solubility.

Hybrid low salinity water and surfactant process for enhancing heavy oil recovery

Combining low salinity water (LSW) with surfactants has an enormous potential for enhancing oil recovery processes. However, there is no consensus about the mechanisms involved, in addition to the fact that several studies have been conducted in model systems, while experiments with rocks and reservoir fluids are scarce. This study presents a core-flooding experiment of LSW injection, with and without surfactant, using the core and heavy oil samples obtained from a sandstone reservoir in southeastern Mexico. The effluents and the crude oil obtained at each stage were analyzed. The study was complemented by tomographic analysis. The results revealed that LSW injection and hybrid process with surfactants obtained an increase of 11.4 percentage points in recovery factor. Various phenomena were caused by LSW flooding, such as changes in wettability and pH, ion exchange, mineral dissolution, detachment of fines and modification of the hydrocarbon profile. In the surfactant flooding, the reduction of interfacial tension and alteration of wettability were the main mechanisms involved. The findings of this work also showed that the conditions believed to be necessary for enhanced oil recovery with LSW, such as the presence of kaolinite or high acid number oil, are not relevant.

Line Patterns Segmentation in Blurred Images Using Contrast Enhancement and Local Entropy Thresholding

Finger vein extraction and recognition hold significance in various applications due to the unique and reliable nature of finger vein patterns. While recently finger vein recognition has gained popularity, there are still challenges associated with extracting and processing finger vein patterns related to image quality, positioning and alignment, skin conditions, security concerns and processing techniques applied. In this paper, a method for robust segmentation of line patterns in strongly blurred images is presented and evaluated in vessel network extraction from infrared images of human fingers. In a four-step process: local normalization of brightness, image enhancement, segmentation and cleaning were involved. A novel image enhancement method was used to re-establish the line patterns from the brightness sum of the independent close-form solutions of the adopted optimization criterion derived in small windows. In the proposed method, the computational resources were reduced significantly compared to the solution derived when the whole image was processed. In the enhanced image, where the concave structures have been sufficiently emphasized, accurate detection of line patterns was obtained by local entropy thresholding. Typical segmentation errors appearing in the binary image were removed using morphological dilation with a line structuring element and morphological filtering with a majority filter to eliminate isolated blobs. The proposed method performs accurate detection of the vessel network in human finger infrared images, as the experimental results show, applied both in real and artificial images and can readily be applied in many image enhancement and segmentation applications.

Microwave enhanced chemical reduction process for nitrite-containing wastewater treatment using sulfaminic acid

High-concentration nitrite-containing wastewater that presents extreme toxicity to human health and organisms is difficult to be treated using traditional biological process. In this study, a novel microwave-enhanced chemical reduction process （MECRP） using sulfarninic acid （SA） was proposed as a new manner to treat such type of wastewater. Based on lab-scale experiments, it was shown that 75%-80% nitrite （NO2-） could be removed within time as short as 4 min under 50 W microwave irradiation in pH range 5-10 when molar ratio of SA to nitrite （SA/NO2-） was 0.8. Pilot-scale investigations demonstrated that MECRP was able to achieve nitrite and chemical oxygen demand （COD） removal with efficiency up to 80% and 20%, respectively under operating conditions of SA concentration 80 kg/m3, SA/NO2- ratio 0.8, microwave power 3.4 kW, and stirring time 3 min. Five-day biological oxygen demand （BODs）/COD value of treated effluent after MECRP was increased from 0.05 to 0.36 （by 620%）, which clearly suggested a considerable improvement of biodegradability for subsequent biological treatment. This study provided a demonstration of using microwave irradiation to enhance reaction between SA and nitrite in a short time, in which nitrite in wastewater was completely converted into nitrogen gas without leaving any sludge and secondary pollutants.

衰竭底水气藏注CO_(2)提高天然气采收率与碳封存机理

气藏注CO_(2)提高天然气采收率并实现碳封存有望成为大幅度提高天然气产量与碳减排协同的潜在关键技术。为了给底水气藏注CO_(2)高效开发提供指导,针对地层水盐度对CO_(2)-CH_(4)-H_(2)O-NaCl体系相平衡影响、气藏注气过程中压力变化对CO_(2)-CH_(4)-H_(2)O-NaCl体系相平衡影响、注采方案对注CO_(2)提高气藏采收率影响、盐度对注CO_(2)提产及封存影响等目前认识不清的问题开展了CO_(2)-CH_(4)-H_(2)O-NaCl体系相平衡规律及注CO_(2)提采与封存数值模拟研究。研究结果表明:①随着盐度增加,CO_(2)和CH_(4)在盐水中的溶解度降低,液相的密度和黏度增加,盐度对气相性质几乎没有影响;②随着压力增加,CO_(2)和CH_(4)在液相中的溶解度均增加,气相、液相密度和黏度均增加,液相偏差因子随压力增加而增加,气相偏差因子先减小后增加;③同注同采方案CH_(4)产量更稳定且产出的CO_(2)少,而先注后采方案则会加速CO_(2)与CH_(4)的混合,CO_(2)封存量低,前者更适合注CO_(2)提采及封存;④在不考虑盐析效应的前提下,盐度对CH_(4)采收率和CO_(2)封存量的影响几乎可以忽略不计,不同盐度的衰竭底水气藏中CH_(4)采收率均超过80%、CO_(2)封存率均超过99%,短期注CO_(2)过程中,CO_(2)主要以气态或超临界态的形式被封存,少部分CO_(2)溶解在液相中,100年后CO_(2)在液相中的溶解质量分数约为5%。结论认为,衰竭底水气藏注CO_(2)能增压补能、驱替置换残余天然气,提高采收率并实现碳封存。

Process Discovery and Refinement of an Enterprise Management System

The need for the analysis of modern businesses is rapidly increasing as the supporting enterprise systems generate more and more data.This data can be extremely valuable for executing organizations because the data allows constant monitoring,analyzing,and improving the underlying processes,which leads to the reduction of cost and the improvement of the quality.Process mining is a useful technique for analyzing enterprise systems by using an event log that contains behaviours.This research focuses on the process discovery and refinement using real-life event log data collected from a large multinational organization that deals with coatings and paints.By investigating and analyzing their order handling pro-cesses,this study aims at learning a model that gives insight inspection of the processes and performance analysis.Furthermore,the animation is also performed for the better inspection,diagnostics,and compliance-related questions to specify the system.The configuration of the system and the conformance checking for further enhancement is also addressed in this research.To achieve the objectives,this research uses process mining techniques,i.e.process discovery in the form of formal Petri nets models with the help of process maps,and process refinement through conformance checking and enhancement.Initially,the identified executed process is reconstructed by using the process discovery techniques.Following the reconstruction,we perform a deep analysis for the underlying process to ensure the process improvement and redesigning.Finally,some recommendations are made to improve the enterprise management system processes.

缩口T型微通道内纳米流体吸收CO_(2)的流动与传质研究

构建了一种气相缩口的T型微通道,研究了二氧化硅(SiO_(2))纳米流体吸收CO_(2)过程的气液两相流动与传质性能。在实验范围内,观察到了泡状流、串珠流、紧密弹状流和弹状-环状流。随着气相流速的增加,泡状流的气泡生成频率f和比表面积a快速增大,串珠流的f和a变化很小,紧密弹状流的f和a逐渐减小。随着连续相和分散相流速的增大以及纳米颗粒浓度的升高,液侧体积传质系数均表现出增大的趋势。与等宽T型通道相比,缩口T型微通道的最大比表面积增幅达29.6%。结果表明气相入口的缩径效应可有效提高气液两相流的传质面积,有利于气液传质性能的改善和提高。

Study on an improved rotating microchannel separator in the intensification for demulsification and separation process

An improved rotating microchannel(IRM) separator was further explored in the intensification for demulsification and separation process. Oil-in-water(O/W) emulsion system of 2-ethylhexyl phosphoric acid-2-ethylhexyl ester(P507)–water without emulsifier was employed to evaluate the performance of the new equipment. In this experiment, the influence on demulsification separation process was explored by changing the geometrical structure and channel height of the microchannel and combining the liquid–liquid two-phase flow pattern, and the correlation general graph between demulsification efficiency and dimensionless parameters was established. The total demulsification effect of the IRM and the separation capacity of the clear organic phase recovered from demulsification are significantly improved. In addition, the liquid–liquid two-phase flow pattern of the clear organic phase after demulsification and the remaining emulsion in the IRM are observed and recorded by high-speed photography. The separation ability of organic phase from the upper outlet can be significantly improved when the total demulsification rate of IRM is up to 90%. There are 3 types and 6 kinds of flow patterns observed. The results demonstrated that the suitable demulsification performance is obtained when the liquid–liquid two-phase inside the IRM is in a parallel pattern. Finally, the relation map between total demulsification efficiency and the universal flow is drawn, which provides a basis for the accurate control of the IRM device.

Enhanced Frequency-Domain Frost Algorithm Using Conjugate Gradient Techniques for Speech Enhancement

In this paper, the frequency-domain Frost algorithm is enhanced by using conjugate gradient techniques for speech enhancement. Unlike the non-adaptive approach of computing the optimum minimum variance distortionless response （MVDR） solution with the correlation matrix inversion, the Frost algorithm implementing the stochastic constrained least mean square （LMS） algorithm can adaptively converge to the MVDR solution in mean-square sense, but with a very slow convergence rate. In this paper, we propose a frequency-domain constrained conjugate gradient （FDCCG） algorithm to speed up the convergence. The devised FDCCG algorithm avoids the matrix inversion and exhibits fast convergence. The speech enhancement experiments for the target speech signal corrupted by two and five interfering speech signals are demonstrated by using a four-channel acoustic-vector-sensor （AVS） micro-phone array and show the superior performance.

A Simple One-Step System Enhances the Availability of High-Quality Sperm for Assisted Reproductive Procedures

Over the last forty years, in vitro fertilization, which has expanded to assisted reproductive technologies (ART), has gone from an experimental procedure to the mainstay of infertility treatment. A technique that once made news with each birth is now responsible for 2% - 3% of the babies born in several nations of the world. This has happened due to significant advances in hormone therapies, culture techniques, and the specialization of equipment designed to support oocytes and embryos. However, for all the advances made to support female fertility, little has changed in male treatment since the advent of intracytoplasmic sperm injection in the early 1990’s. Recently, a number of authors have documented problems with sperm preparation techniques. Some report DNA damage, others membrane and organelle issues, all of which potentially hamper fertilization rates and possibly take-home baby rates. Further, as the clinical workload of ART has increased and staffing shortages have become critical, all labs are looking for simpler, more efficient ways to perform job functions. This study describes a simple, one-step method for preparing semen samples for ART. This new technique minimizes excessive manipulation of the sample compared to current standards and is less likely to cause cell damage. Preliminary results suggest a significant enhancement in recovered sample motility and an optimal sample for ART procedures with minimal sample manipulation.

Application of graph neural network and feature information enhancement in relation inference of sparse knowledge graph

At present,knowledge embedding methods are widely used in the field of knowledge graph(KG)reasoning,and have been successfully applied to those with large entities and relationships.However,in research and production environments,there are a large number of KGs with a small number of entities and relations,which are called sparse KGs.Limited by the performance of knowledge extraction methods or some other reasons(some common-sense information does not appear in the natural corpus),the relation between entities is often incomplete.To solve this problem,a method of the graph neural network and information enhancement is proposed.The improved method increases the mean reciprocal rank(MRR)and Hit@3 by 1.6%and 1.7%,respectively,when the sparsity of the FB15K-237 dataset is 10%.When the sparsity is 50%,the evaluation indexes MRR and Hit@10 are increased by 0.8%and 1.8%,respectively.

Gap-plasmon of Fe3O4@Ag Core-shell Nanostructures for Highly Enhanced Fluorescence Detection of Rhodamine B

A novel gap-plasmon of Fe3O4@Ag core-shell nanoparticles for surface enhanced fluorescence detection of Rhodamine B（RB） was developed. Fe3O4@Ag core-shell nanostructures with Ag shell and Fe3O4 core were synthetized by self-assembled method with the assistance of 3-mercaptopropyl trimethoxy silane（MPTS）. To study the RB fluorescence enhanced by gap-plasmon, the fluorescence properties of RB on the substrates with different nanogap densities were systematically investigated, and the results showed that the fluorescence intensity of RB on Fe3O4@Ag core-shell NPs substrate was much stronger than that on bare glass substrate, and the fluorescence intensity was further improved by using multilayer Fe3O4@Ag core-shell NPs substrate which had higher nanogap density. Different from the mechanism that is based on the maximum overlap of the surface plasmon resonance（SPR） band and emission band, the mechanism of the fluorescence enhancement in our work is based on the localized surface plasmon（LSP） and the gap plasmon near-field coupling with the Fe3O4@Ag core-shell NPs. Besides, the detection limit obtained was as low as 1×10^（-7） mol/L, and the Fe3O4@Ag core-shell NPs substrate had high selectivity for RB fluorophores. It was demonstrated that the Fe3O4@Ag core-shell NPs substrate had activity, good stability, and selectivity for fluorescence detection of RB. And the detection of RB by the surface plasmon enhanced fluorescence was more convenient and rapid than the traditional detection methods in previous works.

Experimental investigation into Fe3O4/SiO2 nanoparticle performance and comparison with other nanofluids in enhanced oil recovery

Nanofluids because of their surface characteristics improve the oil production from reservoirs by enabling different enhanced recovery mechanisms such as wettability alteration,interfacial tension(IFT)reduction,oil viscosity reduction,formation and stabilization of colloidal systems and the decrease in the asphaltene precipitation.To the best of the authors’ knowledge,the synthesis of a new nanocomposite has been studied in this paper for the first time.It consists of nanoparticles of both SiO2 and Fe3O4.Each nanoparticle has its individual surface property and has its distinct effect on the oil production of reservoirs.According to the previous studies,Fe3O4 has been used in the prevention or reduction of asphaltene precipitation and SiO2 has been considered for wettability alteration and/or reducing IFTs in enhanced oil recovery.According to the experimental results,the novel synthesized nanoparticles have increased the oil recovery by the synergistic effects of the formed particles markedly by activating the various mechanisms relative to the use of each of the nanoparticles in the micromodel individually.According to the results obtained for the use of this nanocomposite,understanding reservoir conditions plays an important role in the ultimate goal of enhancing oil recovery and the formation of stable emulsions plays an important role in oil recovery using this method.

基于改进YOLOv5车辆检测方法

针对现有目标检测在智能交通系统和自动驾驶等领域存在车辆目标检测精度低、鲁棒性较差等问题,提出一种基于YOLOv5的车辆目标检测算法。在YOLOv5s网络模型框架中,添加注意力机制增强特征,提取重要特征;添加小目标检测层提升对遮挡重叠弱小目标识别的准确率;引入金字塔池化(SPPFCSPC),提高网络空间特征提取能力;引入损失函数(SIoU_Loss)加快边界框回归速率,提高定位精度,消除重叠检测。基于自制车辆检测数据集进行实验,其结果表明,改进网络模型与原YOLOv5s网络模型相比,不同目标类的平均准确率均有明显提高,平均准确率均值提升3.25%,查准率提高4.14%,召回率提高3.05%,检测速度满足实时性要求。

A-O模式MBBR工艺对村镇社区污水的脱氮效果

采用快速排泥法对硝化型和反硝化型MBBR反应器进行启动,并形成A-O模式工艺处理村镇生活污水。结果显示,通过快速排泥法,可以分别在20 d和10 d内完成硝化生物膜和反硝化生物膜的培养;在填充率为40%时,(20.0±0.5)℃水温条件下填料的平均硝化速率和反硝化速率分别为0.48 kgN/(m^(3)·d)和0.55 kgN/(m^(3)·d);当水温为(16.2±2.4)℃时,不投加外碳源,A-O模式的MBBR工艺出水氨氮和总氮可达到一级A标准;反硝化作用主要发生在缺氧池前端,硝化作用主要发生在好氧池后端。高通量测序结果显示,缺氧池前端反硝化菌主要为异养反硝化菌(相对丰度为19.14%),好氧池从前端到后端,硝化细菌菌属逐渐增加(相对丰度从3.09%增加到11.88%),好氧区填料存在一定比例的反硝化菌属(相对丰度为1.35%~4.11%)。A-O模式纯膜MBBR工艺启动迅速,脱氮效率高,系统简单、易于维护,适用于村镇污水处理。

Hydrogeochemical and isotopic assessment of the origin of NO_(3)^(−)and N-NH_(3)contents in the aquifer located in a closed lacustrine volcano-sedimentary basin in the metropolitan area of Mexico City

To explain the presence and spatial distribution of NO_(3)^(−)and N-NH_(3)in the Aquifer of the Metropolitan Area of Mexico City(AMAMC),a hydrogeochemical and isotopic analysis using^(13)C DIC(as well as the stable isotopes^(18)O and^(2)H)in groundwater was conducted.This aquifer is located in an old closed lacustrine volcano-sedimentary basin;some wells hosted in the semi-confined zone contain high N-NH_(3)concentrations,while others present NO_(3)^(−)contents in the recharge zones(hosted in an oxidizing environment).In this study,a change in the isotopic signature(primarily in^(18)O and^(2)H)was observed from the recharge zones to the basin center in some of the wells with high NO_(3)^(−)concentrations,this behavior can be attributed to evaporation during the incorporation of recently infiltrated water.In addition,the results for^(13)C(along with ^(2) H)in wells with the highest N-NH_(3)concentrations exhibited an atypically broad range of values.Results indicated the occurrence of hydrogeochemical and/or biochemical processes in the aquifer(in an oxidizing or reducing environment),such as organic degradation,bacterial decomposition(primarily in the ancient Lake Texcoco and which acts as a natural sink for carbon,nitrogen,sulfur,and phosphorus),besides rock weathering and dissolution,which may be responsible for a very marked isotopic modification of the^(13)C(and,to a lesser extent,2 H).Methanotrophic bacterial activity and methanogenic activity may be related to N-NH_(3)removal processes by oxidation and residual water incorporation respectively,whereas the increase in the NO_(3)^(−)content in some wells is due to the recent contribution of poor-quality water due to contamination.

Effect of soil archaea on N_(2)O emission in alpine permafrost

Soil microbial communities are pivotal in permafrost biogeochemical cycles,yet the variations of abundant and rare microbial taxa and their impacts on greenhouse gas emissions in different seasons,remain elusive,especially in the case of soil archaea.Here,we conducted a study on soil abundant and rare archaeal taxa during the growing and non-growing seasons in the active layer of alpine permafrost in the Qinghai-Tibetan Plateau.The results suggested that,for the archaeal communities in the sub-layer,abundant taxa exhibited higher diversity,while rare taxa maintained a more stable composition from the growing to non-growing season.Water soluble organic carbon and soil porosity were the most significant environmental variables affecting the compositions of abundant and rare taxa,respectively.Stochastic and deterministic processes dominated the assemblies of rare and abundant taxa,respectively.The archaeal ecological network influenced N_(2)O flux through different modules.Rare taxa performed an essential role in stabilizing the network and exerting important effects on N_(2)O flux.Our study provides a pioneering and comprehensive investigation aimed at unravelling the mechanisms by which archaea or other microorganisms influence greenhouse gas emissions in the alpine permafrost.