The moisture generated by the ageing of the oil-paper insulating system can easily lead to the deterioration of the performance of the insulating *** order to alleviate the impact of moisture on the performance of the...
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The moisture generated by the ageing of the oil-paper insulating system can easily lead to the deterioration of the performance of the insulating *** order to alleviate the impact of moisture on the performance of the insulating paper,we developed a kind of lipophilic hydrophobic self-repairing cellulose insulating paper(new insulating paper)based on the ternary system of polytetrafluoroethylene,fluorocarbon surfactant and fluorinated alkyl silane,and accelerated thermal ageing test for 45 days at 130°C was carried *** experimental results show that the new insulating paper with excellent lipophilic property can realise hydrophobic self-repairing through heat treatment after physical *** tensile strength and elongation at break of the new insulating paper increased by 5%–8%and 6.25%–27%respectively compared with the original cellulose insulating *** the end of ageing,the relative dielectric constant anddielectric loss factor of new insulating paper are 10.4%and 9.9%lower than that of the original cel-lulose insulating paper,while the breakdown voltage is 6.8%*** acid and moisture content producedduring the ageing process of the insulating oil impregnated with new insulating paper are also less,indicating that the coating can delay the ageing of the insulating paper.
Lost circulation, a recurring peril during drilling operations, entails substantial loss of drilling fluid anddire consequences upon its infiltration into the formation. As drilling depth escalates, the formation tem...
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Lost circulation, a recurring peril during drilling operations, entails substantial loss of drilling fluid anddire consequences upon its infiltration into the formation. As drilling depth escalates, the formation temperature and pressure intensify, imposing exacting demands on plug materials. In this study, a kind of controllable curing resin with dense cross-network structure was prepared by the method of solution stepwise ring-opening polymerization. The resin plugging material investigated in this study is a continuous phase material that offers effortless injection, robust filling capabilities, exceptional retention, and underground curing or crosslinking with high strength. Its versatility is not constrained by fracture-cavity lose channels, making it suitable for fulfilling the essential needs of various fracture-cavity combinations when plugging fracture-cavity carbonate rocks. Notably, the curing duration can be fine-tuned within the span of 3-7 h, catering to the plugging of drilling fluid losing of diverse fracture dimensions. Experimental scrutiny encompassed the rheological properties and curing behavior of the resin plugging system, unraveling the intricacies of the curing process and establishing a cogent kinetic model. The experimental results show that the urea-formaldehyde resin plugging material has a tight chain or network structure. When the concentration of the urea-formaldehyde resin plugging system solution remains below 30%, the viscosity clocks in at a meager 10 mPa·s. Optimum curing transpires at 60℃, showcasing impressive resilience to saline conditions. remarkably, when immersed in a composite saltwater environment containing 50000 mg/L NaCl and 100000 mg/L CaCl_(2), the urea-formaldehyde resin consolidates into an even more compact network structure, culminating in an outstanding compressive strength of 41.5 MPa. Through resolving the correlation between conversion and the apparent activation energy of the non-isothermal dSC curing reac
As drilling wells continue to move into deep ultra-deep layers,the requirements for temperature resistance of drilling fluid treatments are getting higher and *** them,blocking agent,as one of the key treatment agents...
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As drilling wells continue to move into deep ultra-deep layers,the requirements for temperature resistance of drilling fluid treatments are getting higher and *** them,blocking agent,as one of the key treatment agents,has also become a hot spot of *** this study,a high temperature resistant strong adsorption rigid blocking agent(QW-1)was prepared using KH570 modified silica,acrylamide(AM)and allyltrimethylammonium chloride(TMAAC).QW-1 has good thermal stability,average particle size of 1.46μm,water contact angle of 10.5.,has a strong hydrophilicity,can be well dispersed in *** experimental results showed that when 2 wt%QW-1 was added to recipe A(4 wt%bentonite slurry+0.5 wt%dSP-1(filtration loss depressant)),the API filtration loss decreased from 7.8to 6.4 m *** aging at 240.C,the API loss of filtration was reduced from 21 to 14 m L,which has certain performance of high temperature loss of *** the same time,it is effective in sealing 80-100mesh and 100-120 mesh sand beds as well as 3 and 5μm ceramic sand *** the same conditions,the blocking performance was superior to silica(5μm)and calcium carbonate(2.6μm).In addition,the mechanism of action of QW-1 was further *** results show that QW-1 with amide and quaternary ammonium groups on the molecular chain can be adsorbed onto the surface of clay particles through hydrogen bonding and electrostatic interaction to form a dense blocking layer,thus preventing further intrusion of drilling fluid into the formation.
In the present work, we proposed the development of a new type of biomedical alloy-NiCrMoTa with improved structural properties compared to the basic NiCrMo alloy. The studied alloys were obtained by melting in a vacu...
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Chemical looping oxidative dehydrogenation (CL-OdH) is an economically promising method for convertingethane into higher value-added ethylene utilizing lattice oxygen in redox catalysts, also known as oxygen carriers....
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Chemical looping oxidative dehydrogenation (CL-OdH) is an economically promising method for convertingethane into higher value-added ethylene utilizing lattice oxygen in redox catalysts, also known as oxygen carriers. Inthis study, perovskite-type oxide SrCoO_(3-δ) and B-site Mn ion-doped oxygen carriers (SrCo_(1-x)MnxO_(3-δ), x=0.1, 0.2, 0.3)were prepared and tested for the CL-OdH of ethane. The oxygen-deficient perovskite SrCoO_(3-δ) exhibited high ethyleneselectivity of up to 96.7% due to its unique oxygen vacancies and lattice oxygen migration rates. However, its low ethyleneyield limits its application in the CL-OdH of ethane. Mn doping promoted the reducibility of SrCoO_(3-δ) oxygen carriers,thereby improving ethane conversion and ethylene yield, as demonstrated by characterization and evaluation experiments.X-ray diffraction results confirmed the doping of Mn into the lattice of SrCoO_(3-δ), while X-ray photoelectron spectroscopy(XPS) indicated an increase in lattice oxygen ratio upon incorporation of Mn into the SrCoO_(3-δ) lattice. Additionally, H2temperature-programmedreduction (H2-TPr) tests revealed more peaks at lower temperature reduction zones and a declinein peak positions at higher temperatures. Among the four tested oxygen carriers, SrCo0.8Mn0.2O_(3-δ) exhibited satisfactoryperformance with an ethylene yield of 50% at 710 °C and good stability over 20 redox cycles. The synergistic effect of Mnplays a key role in increasing ethylene yields of SrCoO_(3-δ) oxygen carriers. Accordingly, SrCo0.8Mn0.2O_(3-δ) shows promisingpotential for the efficient production of ethylene from ethane via CL-OdH.
Additive manufacturing (AM) is the industrial production name for 3d printing, a computer-controlled process that creates three dimensional objects by deposing materials, usually in layers. The improvement of the tech...
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rock breaking efficiency of drill bits is an important index for measuring the drilling efficiency in the oil and gas drilling field, and it is influenced by many factors, such as structure and material. This study de...
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rock breaking efficiency of drill bits is an important index for measuring the drilling efficiency in the oil and gas drilling field, and it is influenced by many factors, such as structure and material. This study developed a calculation model and an experimental model of rock breaking of polycrystalline diamond compact (PdC) anddiamond impregnated cutter (dIC) hybrid bit to reveal the influence of bit structure and material on tangential force, axial force and wear height. On the basis of the calculation model of the co-rail arrangement of the PdC–dIC hybrid bit and the rock breaking mode, a rock breaking mechanical parameter prediction model and a rock breaking performance test model were established. rock stress calculation method, rock failure criterion, and mechanical specific energy (MSE) calculation method were used to analyze the rock stress and the relationship between MSE and tangential force, axial force, and wear height during combinedrock breaking. The accuracy of the model was verified by experiments. results show that the specific work of rock breaking of the PdC-dIC hybrid bit is less than that of PdC, and a reverse nonlinearrelationship exists between specific work of rock breaking and wear height. The energy required for hybrid bit to break rock is less than that of PdC bit. A positive nonlinearrelationship exists between the energy of PdC-dIC hybrid bit and the wear height, whereas the cutting depth and the wear height show a negative nonlinearrelationship. The stress distribution of PdC rock breaking is uniform, and the maximum equivalent stress is up to 104 MPa. The stress distribution of rock breaking of the hybrid PdC-dIC is extremely nonuniform, and stress concentration occurs with a minimum equivalent stress of 84 MPa and a maximum stress of 161 MPa, which is beneficial to rock breaking. rock breaking of PdC-dIC hybrid bit can promote the generation anddevelopment of rock cracks, thereby reducing the crushing strength of the rock. The
In order to accurately predict the content and variation trend of dissolved gas in trans-former oil and guide the condition maintenance of power transformers,a combined prediction model based on multi-information fusi...
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In order to accurately predict the content and variation trend of dissolved gas in trans-former oil and guide the condition maintenance of power transformers,a combined prediction model based on multi-information fusion is proposed and its effectiveness is *** of all,based on the possibility of pathological and missing historical sample data,a detection and filling method based on variable weight combination samples is ***,the authors propose two *** at the non-linear and non-stationary characteristics of gas content,a univariate decomposition prediction mode HBA-VMd-TCN which based on the Honey Badger algorithm,variational mode decomposition and time convolutional network(TCN)is *** the multi-variate Informer prediction model is established for gas content affected by multiple ***,the cross-entropy theory is used to determine the weight coefficients of the two models,and the multi-information fusion combined prediction model is ***,on the basis of the above,a method to determine the time step and the position information of the transition point adaptively in the process of prediction is proposed to further improve the prediction *** results show that,through a series of simulation experiments of model comparison and transformer anomaly prediction,the accuracy and effectiveness of the combined prediction model are verified.
To control the lateral motion of autonomous vehicles, their precise lateral dynamics models are required. However, vehicles inherently exhibit nonlinear characteristics, and the model of a vehicle changes according to...
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Scientifc interpretation of paradigm. The concept and theory of paradigm were first proposed by Thomas Kuhn, a famous American science philosopher, and were systematically described in his book “The Structure of Scie...
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Scientifc interpretation of paradigm. The concept and theory of paradigm were first proposed by Thomas Kuhn, a famous American science philosopher, and were systematically described in his book “The Structure of Scientific revolutions” [1] published in 1962. He pointed out that a paradigm
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