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The critical rate of horizontal wells in bottom-water reservoirs with an impermeable barrier 被引量:7
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作者 Yue Ping Du Zhimin +1 位作者 Chen Xiaofan Liang Baosheng 《Petroleum Science》 SCIE CAS CSCD 2012年第2期223-229,共7页
Barrier impacts on water cut and critical rate of horizontal wells in bottom water-drive reservoirs have been recognized but not investigated quantitatively. Considering the existence of impermeable barriers in oil fo... Barrier impacts on water cut and critical rate of horizontal wells in bottom water-drive reservoirs have been recognized but not investigated quantitatively. Considering the existence of impermeable barriers in oil formations, this paper developed a horizontal well flow model and obtained mathematical equations for the critical rate when water cresting forms in bottom-water reservoirs. The result shows that the barrier increases the critical rate and delays water breakthrough. Further study of the barrier size and location shows that increases in the barrier size and the distance between the barrier and oil-water contact lead to higher critical rates. The critical rate gradually approaches a constant as the barrier size increases. The case study shows the method presented here can be used to predict the critical rate in a bottom-water reservoir and applied to investigate the water cresting behavior of horizontal wells. 展开更多
关键词 Horizontal well bottom-water reservoir barriers critical rate cresting
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Critical cooling rate on carbide precipitation during quenching of austenitic manganese steel 被引量:4
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作者 Youn-Soo Ham Jeong-Tae Kim +2 位作者 Si-Young Kwak Jeong-Kil Choi Woo-Young Yoon 《China Foundry》 SCIE CAS 2010年第2期178-182,共5页
Critical cooling rate to avoid carbide precipitation during quenching of austenitic manganese steel was investigated by means of optical microscopy,image analyzer and numerical analysis.An efficient heat treatment ana... Critical cooling rate to avoid carbide precipitation during quenching of austenitic manganese steel was investigated by means of optical microscopy,image analyzer and numerical analysis.An efficient heat treatment analysis program including temperature-dependent material properties was developed for the prediction of cooling rate and probability of carbide precipitation during quenching by finite difference method.Time-dependent heat transfer coefficient was adopted to achieve more precise results.Area ratio of carbide precipitation was measured by image analyzer to determine the critical point of carbide precipitation.Temperature-dependent critical cooling rate at that point was calculated by the developed numerical program.Finally,the probability of carbide precipitation on the whole area of specimen can be predicted by the proposed numerical program and the numerical result of a specimen was compared with the experimental result. 展开更多
关键词 austenitic manganese steel carbide precipitation QUENCHING critical cooling rate
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Experimental Analysis of the Flow Characteristics of an Adjustable Critical-Flow Venturi Nozzle
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作者 Chun Ye Jingjing Gao +4 位作者 Zhihui Wang Weibiao Zheng Yibei Wang Xingkai Zhang Ming Liu 《Fluid Dynamics & Materials Processing》 EI 2023年第3期754-765,共12页
The response of an adjustable critical-flow Venturi nozzle is investigated through a set indoor experiments aimed to determine the related critical flow rate,critical pressure ratio,and discharge coefficient.The effec... The response of an adjustable critical-flow Venturi nozzle is investigated through a set indoor experiments aimed to determine the related critical flow rate,critical pressure ratio,and discharge coefficient.The effect of a variation in the cone displacement and liquid content on the critical flow characteristics is examined in detail and it is shown that the former can be used to effectively adjust the critical flow rate.The critical pressure ratio of the considered nozzle is above 0.85,and the critical flow control deviation of the gas flow is within±3%.Liquid flow can reduce the gas critical mass flow rate accordingly,especially for the cases with larger liquid volume and lower inlet pressure.The set of results and conclusions provided are intended to support the optimization of steam injection techniques in the context of heavy oil recovery processes. 展开更多
关键词 Adjustable critical flow venturi nozzle critical pressure ratio critical mass flow rate gas-liquid two-phase critical flow
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Estimation of Critical Rate of Temperature Rise for Thermal Explosion of First Order Autocatalytic Decomposition Reaction Systems by Using Non-isothermal DSC 被引量:1
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作者 GUOPeng-jiang HURong-zu +8 位作者 ZHANGHai XIAZhi-ming SONGJi-rong GAOSheng-li NINGBin-ke SHIQi-zhen LIURong LUGui-e JIANGJi-you 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2004年第2期163-165,共3页
A method of estimating the critical rate of temperature rise for the thermal explosion of first order autocatalytic decomposition reaction systems by using non-isothermal DSC is presented. The information was obtained... A method of estimating the critical rate of temperature rise for the thermal explosion of first order autocatalytic decomposition reaction systems by using non-isothermal DSC is presented. The information was obtained on the increasing rate of temperature for the first order autocatalytic decomposition of nitrocellulose containing 13.86% nitrogen converting into the thermal explosion. 展开更多
关键词 DSC critical rate of temperature rise NC Non-isothermal change Thermal explosion
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Identifying the critical phosphorus balance for optimizing phosphorus input and regulating soil phosphorus effectiveness in a typical winter wheat-summer maize rotation system in North China
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作者 XU Meng-ze WANG Yu-hong +6 位作者 NIE Cai-e SONG Gui-pei XIN Su-ning LU Yan-li BAI You-lu ZHANG Yin-jie WANG Lei 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2023年第12期3769-3782,共14页
Phosphorus(P)is a nonrenewable resource and a critical element for plant growth that plays an important role in improving crop yield.Excessive P fertilizer application is widespread in agricultural production,which no... Phosphorus(P)is a nonrenewable resource and a critical element for plant growth that plays an important role in improving crop yield.Excessive P fertilizer application is widespread in agricultural production,which not only wastes phosphate resources but also causes P accumulation and groundwater pollution.Here,we hypothesized that the apparent P balance of a crop system could be used as an indicator for identifying the critical P input in order to obtain a high yield with high phosphorus use efficiency(PUE).A 12-year field experiment with P fertilization rates of 0,45,90,135,180,and 225 kg P_(2)O_(5)ha^(-1)was conducted to determine the crop yield,PUE,and soil Olsen-P value response to P balance,and to optimize the P input.Annual yield stagnation occurred when the P fertilizer application exceeded a certain level,and high yield and PUE levels were achieved with annual P fertilizer application rates of 90-135 kg P_(2)O_(5)ha^(-1).A critical P balance range of 2.15-4.45 kg P ha^(-1)was recommended to achieve optimum yield with minimal environmental risk.The critical P input range estimated from the P balance was 95.7-101 kg P_(2)O_(5)ha^(-1),which improved relative yield(>90%)and PUE(90.0-94.9%).In addition,the P input-output balance helps in assessing future changes in Olsen-P values,which increased by 4.07 mg kg^(-1)of P for every 100 kg of P surplus.Overall,the P balance can be used as a critical indicator for P management in agriculture,providing a robust reference for limiting P excess and developing a more productive,efficient and environmentally friendly P fertilizer management strategy. 展开更多
关键词 yield of winter wheat and summer maize phosphorus balance phosphorus use efficiency OLSEN-P critical phosphorus application rate
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Simulation of critical cooling rate and process conditions for metallic glasses in vertical type twin-roll casting 被引量:1
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作者 Zhi-pu PEI Dong-ying JU Xue LI 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2017年第11期2406-2414,共9页
Critical cooling rates for producing metallic glasses were evaluated based on a calculated continuous cooling transformation(CCT)diagram.Temperature distributions of the melt in molten pool in the vertical type twin-r... Critical cooling rates for producing metallic glasses were evaluated based on a calculated continuous cooling transformation(CCT)diagram.Temperature distributions of the melt in molten pool in the vertical type twin-roll casting(VTRC)process of metallic glasses were simulated,and cooling rates under different casting conditions were calculated with the simulated results.By comparing the results obtained by CCT diagrams and simulation,the possibility of producing metallic glasses by the VTRC method and influences of casting conditions on cooling rate were discussed.The results reveal that cooling rate with3or4orders of magnitude by the VTRC process can be attained in producing Mg-based metallic glasses,which is faster than the critical cooling rate calculated by the CCT diagram.One side pouring mode can improve the temperature distributions of casting pool.VTRC process has a good ability in continuous casting metallic glassy thin strips. 展开更多
关键词 metallic glass critical cooling rate twin-roll casting SIMULATION
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Ultra Fast Spray Cooling and Critical Droplet Daimeter Estimation from Cooling Rate 被引量:1
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作者 Muhammad Aamir Liao Qiang +2 位作者 Zhu Xun Wang Hong Muhammad Zubair 《Journal of Power and Energy Engineering》 2014年第4期259-270,共12页
Spray cooling is an effective tool to dissipate high heat fluxes from hot surfaces. This paper thoroughly investigates the effects of spray parameters on the cooling time and cooling rate under varying inlet pressure ... Spray cooling is an effective tool to dissipate high heat fluxes from hot surfaces. This paper thoroughly investigates the effects of spray parameters on the cooling time and cooling rate under varying inlet pressure using water as the coolant. Cylindrical samples of stainless steel with constant diameter, D = 25 mm, and thickness δ: 8.5 mm, 13 mm, 17.5 mm and 22 mm were investigated. Critical droplet diameter to achieve an ultrafast cooling rate of 300&deg;C/s was estimated by using analytical model for samples of varying thickness. At an inlet pressure of 0.8 MPa, maximum cooling rates of 424.2&deg;C/s, 502.81&deg;C/s and 573.1&deg;C/s were achieved for wall super heat ΔT = 600&deg;C, 700&deg;C and 800&deg;C respectively. 展开更多
关键词 Spray COOLING ULTRA FAST COOLING rate INLET Pressure critical DROPLET Diameter
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The Mechanism of Critical Strain of Serrated Yielding in Strain Rate Domain
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作者 符师桦 蔡玉龙 +2 位作者 杨素丽 张青川 伍小平 《Chinese Physics Letters》 SCIE CAS CSCD 2016年第2期79-82,共4页
The mechanism of the critical strain of serrated yielding is studied via tension tests at various strain rates. Betore the critical strain, it is deduced that dislocations are not pinned at high strain rates, and disl... The mechanism of the critical strain of serrated yielding is studied via tension tests at various strain rates. Betore the critical strain, it is deduced that dislocations are not pinned at high strain rates, and dislocations at low strain rates are pinned but cannot escape. The critical strain depends on the first pinning process at high strain rates and on the first unpinning process at low strain rates. The calculated results based on the two criteria are in good consistency with the experiment. 展开更多
关键词 of IS The Mechanism of critical Strain of Serrated Yielding in Strain rate Domain that rate HIGH
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Improvement in cryosurvival of buffalo bull (Bubalus bubalis) sperm by altering freezing rate within critical temperature range
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作者 Jasmer Dalal Ajeet Kumar +5 位作者 Pradeep Kumar Mrigank Honparkhe Vijay Singh Malik Sumit Singhal Simarjeet Kaur Parkash Singh Brar 《Asian pacific Journal of Reproduction》 2018年第2期72-78,共7页
Objective:To optimize the cryopreservation of buffalo bull semen by altering freezing rates within critical temperature range (4℃ to -60℃). Methods: A total of 20 ejaculates each from 5 Murrah buffalo bulls were cry... Objective:To optimize the cryopreservation of buffalo bull semen by altering freezing rates within critical temperature range (4℃ to -60℃). Methods: A total of 20 ejaculates each from 5 Murrah buffalo bulls were cryopreserved using programmable biofreezer in 2 phases. In the 1st phase, 9 freezing rates were applied at -2, -5, -10, -20, -30, -40, -50, -60 or -4℃/min (control) from 4℃ to -15℃;at -40℃/min from -15℃ to -60℃. In the 2nd phase, a fixed freezing rate was applied at -30℃/min from 4℃ to -15℃. Six freezing rates were applied at -10, -20, -30, -40 (control), -50 or -60℃/min from -15℃ to -60℃. The freezing from -60℃ to -140℃ were fixed at -50℃/min in both the phases. Post thaw semen quality was assessed in terms of motility, viability, membrane integrity (hypo-osmotic swelling test), sperm abnormalities, and active mitochondria. Data were arc sine transformed and analyzed through one-way analysis of variance using SPSS software. Results: In the 1st phase, percent individual motility, progressive motility and viability were similar among various protocols. Percent hypo-osmotic swelling reactive sperm was higher with freezing at -30℃/min. In the 2nd phase, percent individual motility, viability and hypo-osmotic swelling reactive sperm was higher with freezing at -50℃/min. Sperm head abnormalities were lower at -30℃/min in the 1st phase, but were similar among the protocols of the 2nd phase. Percent active mitochondria were higher at -30℃/min in the 1st phase and at -50℃/min in the 2nd phase.Conclusions:The optimum post thaw semen quality of buffalo bull could be obtained by applying freezing rate at -30℃/min (4℃ to -15℃) and at -50℃/min (-15℃ to -140℃), followed by plunging of straws in into liquid nitrogen for storage. 展开更多
关键词 BUFFALO BULLS FREEZING rate critical temperature range Programmed FREEZING
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A new model for predicting the critical liquid-carrying velocity in inclined gas wells
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作者 WANG Wujie CUI Guomin +1 位作者 WEI Yaoqi PAN Jie 《Petroleum Exploration and Development》 CSCD 2021年第5期1218-1226,共9页
Based on the assumption of gas-liquid stratified flow pattern in inclined gas wells,considering the influence of wettability and surface tension on the circumferential distribution of liquid film along the wellbore wa... Based on the assumption of gas-liquid stratified flow pattern in inclined gas wells,considering the influence of wettability and surface tension on the circumferential distribution of liquid film along the wellbore wall,the influence of the change of the gas-liquid interface configuration on the potential energy,kinetic energy and surface free energy of the two-phase system per unit length of the tube is investigated,and a new model for calculating the gas-liquid distribution at critical conditions is developed by using the principle of minimum energy.Considering the influence of the inclination angle,the calculation model of interfacial friction factor is established,and finally closed the governing equations.The interface shape is more vulnerable to wettability and surface tension at a low liquid holdup,resulting in a curved interface configuration.The interface is more curved when the smaller is the pipe diameter,or the smaller the liquid holdup,or the smaller the deviation angle,or the greater gas velocity,or the greater the gas density.The critical liquid-carrying velocity increases nonlinearly and then decreases with the increase of inclination angle.The inclination corresponding to the maximum critical liquid-carrying velocity increases with the increase of the diameter of the wellbore,and it is also affected by the fluid properties of the gas phase and liquid phase.The mean relative errors for critical liquid-carrying velocity and critical pressure gradient are 1.19%and 3.02%,respectively,and the misclassification rate is 2.38%in the field trial,implying the new model can provide a valid judgement on the liquid loading in inclined gas wells. 展开更多
关键词 inclined gas well gas-liquid phase distribution interfacial friction factor critical liquid-carrying velocity bottom-hole liquid loading
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The Impact of Rate of Feeding Advancement after Early Initiation of Enteral Nutrition in Critically Ill, Underweight Patients: A Single-Center Retrospective Chart Review
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作者 Satomi Ichimaru Maren Sono +2 位作者 Hidetoshi Fujiwara Ryutaro Seo Koichi Ariyoshi 《Food and Nutrition Sciences》 2016年第11期939-954,共16页
Background: The optimal rate of feeding advancement after initiation of early enteral nutrition (EEN) for underweight, critically ill patients is unknown. Methods: We conducted a retrospective chart review in intensiv... Background: The optimal rate of feeding advancement after initiation of early enteral nutrition (EEN) for underweight, critically ill patients is unknown. Methods: We conducted a retrospective chart review in intensive care unit (ICU) patients with a body mass index (BMI) < 20.0 kg/m<sup>2</sup>. Patients were categorized into Group R, which reached the energy target within 3 days of EEN initiation, and Group S, which reached the energy target 4 or more days after EEN initiation. Results: A total of 65 patients with a median age of 73 years were included in the study. No significant differences were observed between the two groups for all-cause mortality, ICU-free days, or length of hospital stay. Ventilator-free days (VFDs) were significantly fewer in Group R than in Group S (18.0 [0.0 - 22.0] vs. 21.0 [16.3 - 24.8] days;P = 0.046). A significantly higher number of patients requiring mechanical ventilation (MV) at hospital discharge were observed in Group R than in Group S (29% vs. 8%;P = 0.030). Multivariable analyses with adjustment for confounders found that days required to reach target energy intake after EEN initiation were significantly and independently associated with the requirement for MV at hospital discharge, but not with VFDs. Conclusion: A slow rate of feeding advancement after initiation of EEN in critically ill patients having a BMI of <20.0 kg/m<sup>2</sup> might be associated with a reduced requirement for MV at hospital discharge. These results require confirmation in a large multicenter trial of underweight, critically ill patients. 展开更多
关键词 critical Illness UNDERWEIGHT Mechanical Ventilation Early Enteral Nutrition rate of Feeding Advancement
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Innovative Teaching Research on Literary Theory and Criticism
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作者 HOU Xia 《Sino-US English Teaching》 2024年第7期309-313,共5页
As a core compulsory course for English majors majoring in teacher education,Literary Theory and Criticism plays an important role in enhancing text understanding,cultivating critical thinking,and shaping correct valu... As a core compulsory course for English majors majoring in teacher education,Literary Theory and Criticism plays an important role in enhancing text understanding,cultivating critical thinking,and shaping correct values in the future development of students.Influenced by traditional teaching ideas,students have many difficulties when learning this course,such as insufficient theoretical understanding,inadequate ability improvement,and not enough investment in course learning.In response to the above issues,this course focuses closely on the fundamental task of“cultivating virtue and nurturing people”,relying on modern information technology and introducing research methods of digital humanities.This course uses“7C”teaching mode under the“three-level integration”,in which“teaching”and“education”are carried out synchronously,and“teacher”and“student”are developed together,in order to greatly enhance students’learning participation and course satisfaction. 展开更多
关键词 literary theory and criticism double helix 7C teaching mode three-level integration participation rate satisfaction level
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Single-Channel Speech Enhancement Using Critical-Band Rate Scale Based Improved Multi-Band Spectral Subtraction 被引量:1
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作者 Navneet Upadhyay Abhijit Karmakar 《Journal of Signal and Information Processing》 2013年第3期314-326,共13页
This paper addresses the problem of single-channel speech enhancement in the adverse environment. The critical-band rate scale based on improved multi-band spectral subtraction is investigated in this study for enhanc... This paper addresses the problem of single-channel speech enhancement in the adverse environment. The critical-band rate scale based on improved multi-band spectral subtraction is investigated in this study for enhancement of single-channel speech. In this work, the whole speech spectrum is divided into different non-uniformly spaced frequency bands in accordance with the critical-band rate scale of the psycho-acoustic model and the spectral over-subtraction is carried-out separately in each band. In addition, for the estimation of the noise from each band, the adaptive noise estimation approach is used and does not require explicit speech silence detection. The noise is estimated and updated by adaptively smoothing the noisy signal power in each band. The smoothing parameter is controlled by a-posteriori signal-to-noise ratio (SNR). For the performance analysis of the proposed algorithm, the objective measures, such as, SNR, segmental SNR, and perceptual evaluations of the speech quality are conducted for the variety of noises at different levels of SNRs. The speech spectrogram and objective evaluations of the proposed algorithm are compared with other standard speech enhancement algorithms and proved that the musical structure of the remnant noise and background noise is better suppressed by the proposed algorithm. 展开更多
关键词 SINGLE-CHANNEL SPEECH Enhancement critical-Band rate SCALE Spectral Over-Subtraction Adaptive Noise Estimation Objective Measure SPEECH Spectrograms
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Effects of charge size on explosives thermal initiation critical temperature under constrained conditions 被引量:2
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作者 王洪伟 智小琦 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2015年第3期234-239,共6页
In order to study the relationship between charge size and thermal initiation critical temperature of explosive in defined conditions,cook-off test about JH explosive was carried out at a heating rate of 1 ℃/min usin... In order to study the relationship between charge size and thermal initiation critical temperature of explosive in defined conditions,cook-off test about JH explosive was carried out at a heating rate of 1 ℃/min using self-designed cook-off experiment setup based on thermostatic control technology.Numerical simulation was conducted to study the effects of different charge sizes on thermal initiation critical temperature of explosives with FLUENT software.Experiment results show that there is a thermal initiation critical temperature in cook-off bomb.Simulation results show that when the ratio of the length to diameter of explosives grains is a fixed value,the thermal initiation critical temperature of explosives decreases with the increase of the diameter of explosives grains.When the grains diameter of explosives increase up to a certain value,the influence of charge size on thermal initiation critical temperature tends to be weakened.Charge size has no influence on the ignition point of explosives.The ignition point is always in the center of the grain. 展开更多
关键词 heating rate thermal initiation thermostatic critical temperature slow cook-off
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Comparison between the Methods of Determining the Critical Stress for Initiation of Dynamic Recrystallization in 316 Stainless Steel 被引量:2
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作者 M.Jafari A.Najafizadeh 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2008年第6期840-844,共5页
Several methods have been proposed to calculate the critical stress for initiation of dynamic recrystallization (σc) on the basis of mathematical methods. One' of them is proposed by Stewart et al. in which this c... Several methods have been proposed to calculate the critical stress for initiation of dynamic recrystallization (σc) on the basis of mathematical methods. One' of them is proposed by Stewart et al. in which this critical point appears as a distinct minimum in the (-dθ/dσ vs σ) through differentiating from θ vs σ. Another one is presented by Najafizadeh and Jonas by modifying the Poliak and Jonas method. According to this method, the strain hardening rate was plotted against flow stress, and the value of σc was attained numerically from the coefficients of the third-order equation that was the best fit from the experimental θ-σ data. Hot compression tests were used in the range of 1000 to 1100℃ with strain rates of 0.01^-1 s^-1 and strain of I on 316 stainless steel. The result shows that Najafizadeh and Jonas method is simpler than the previous one, and has a good agreement with microstructures. Furthermore, the value of normalized critical stress for this steel was obtained uc=σc/σp=0.92. 展开更多
关键词 Dynamic recrystallization critical stress Strain hardening rate
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Numerical Experiments on Critical Ventilation Velocity and Back-layer in Tunnel Fire 被引量:3
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作者 杨培中 金浩 +1 位作者 邵钢 金先龙 《Journal of Donghua University(English Edition)》 EI CAS 2006年第3期42-46,共5页
Full-scale numerical experiments were carried out on the vehicular fire in a long tunnel to study the critical ventilation velocity and back-layer distance with heat release rate of 5, 20 and 100 MW respectively. A co... Full-scale numerical experiments were carried out on the vehicular fire in a long tunnel to study the critical ventilation velocity and back-layer distance with heat release rate of 5, 20 and 100 MW respectively. A computational fluid dynamics (CFD) model of fire-driven fluid flow FDS(Fire Dynamics Simulator) was used to solve numerically a form of the Navier-Stokes equations for fire. The results were compared with the expressions proposed in the literature. A modified equation for the critical ventilation velocity was given to better fit the experimental results. A bi-exponential model that well fitted the numerical experimental results was proposed to describe the relationship between back-layer distance and ventilation velocity. 展开更多
关键词 tunnel fire critical ventilation velocity heatrelease rate back-layer hi-exponential model.
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The Antifreeze Critical Strength of Low-temperature Concrete Effected by Index 被引量:1
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作者 刘军 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2011年第2期355-360,共6页
The antifreeze critical strength and the pre-curing time of low-temperature concrete were studied by means of guaranteed rate of compressive strength and antifreeze performance for the structural safety requirement of... The antifreeze critical strength and the pre-curing time of low-temperature concrete were studied by means of guaranteed rate of compressive strength and antifreeze performance for the structural safety requirement of concrete engineering,suffering once freeze damage under air environment.It is shown that the antifreeze critical strength is 3.7-4.4MPa,pre-curing time is 18-32 h by guaranteed rate of compressive strength,and the antifreeze critical strength is 3.7-4.4MPa,pre-curing time is 18-32 h by guaranteed rate of antifreeze performance.It can be found that the method of guaranteed rate of compressive strength is sensitive to the defect which generated by freeze damage in the concrete interior.The method is fit to evaluate the antifreeze critical strength of low-temperature concrete. 展开更多
关键词 guaranteed rate of compressive strength guaranteed rate of antifreeze performance antifreeze critical strength once freeze under air environment
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Critical parameters of horizontal well influenced by semi-permeable barrier in bottom water reservoir 被引量:6
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作者 乐平 杜志敏 +2 位作者 陈小凡 朱苏阳 贾虎 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第4期1448-1455,共8页
It is well-known that barriers have a significant impact on the production performance of horizontal wells developed in a bottom water drive reservoir. In most cases, reservoir barriers are semi-permeable. Based on pr... It is well-known that barriers have a significant impact on the production performance of horizontal wells developed in a bottom water drive reservoir. In most cases, reservoir barriers are semi-permeable. Based on previous research on impermeable reservoir barrier, a mathematical flow model was derived for a horizontal well of a bottom water drive reservoir with a semi-permeable barrier. Besides, analytical equations were also presented to calculate critical parameters, such as production rate,pressure and potential difference. The effects of barrier, well and reservoir parameters on our model results were further investigated.The results show that the larger the barrier size is or the higher the barrier location is, the higher the critical production rate and potential difference of a horizontal well are. When the barrier permeability equals the formation permeability or the barrier width equals zero, the critical production rates converge to the values same to that of the case with no barrier. When the barrier permeability equals zero, the problem is regarded as a case of impermeable barrier. This model can be applied to predicting horizontal wells' critical production parameters in reservoirs with semi-permeable barriers. 展开更多
关键词 horizontal well bottom water reservoir semi-permeable barrier critical rate cresting
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STRESS-STBAIN FIELD NEAR CRACK TIP AND CALCULATION OF CRITICAL STRESS OF CRACK PROPAGATION IN A PURE BENDING BEAM OF RECTANGULAR SECTION WITH ONE-SIDED MODEICRACK
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作者 刘汉池 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1995年第8期779-789,共11页
This paper studies the stress-sirain field near crack tip in a pure bending beam ofrectangular section with one-sided mode I crack by the analytic method of Rej [1],then it gives the stress and strain components at th... This paper studies the stress-sirain field near crack tip in a pure bending beam ofrectangular section with one-sided mode I crack by the analytic method of Rej [1],then it gives the stress and strain components at the crack tip when the crackpropagates and further it obtains the formulas of calculating the elastic deformed areawidth, the deformed intensity, area width and the equation groups of calculating thecritical stress of crack propagation, last the equation group of calculating criticalstress of crack propagation is verified by calculating instance. The maximum error is0. 18%. 展开更多
关键词 critical stress of crack propagation plastic-elastic rate near cracktip transforming rate
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Invasive Procedures and Length of Stay among Critically Ill Patients in ICU over Three Years: A Retrospective Study
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作者 Mohammad Al-Naeem Alaa Abuatallah 《Open Journal of Nursing》 2019年第7期765-778,共14页
Introduction: Intensive care unit (ICU) provides advanced specialized medical and nursing care for critically ill patients. Advanced monitoring techniques are needed to prevent physiologic deterioration, while the und... Introduction: Intensive care unit (ICU) provides advanced specialized medical and nursing care for critically ill patients. Advanced monitoring techniques are needed to prevent physiologic deterioration, while the underlying disease treated and resolved. Frequents invasive procedure and treatment are used and affect the death rate and length of hospitalization. This study aimed to describe the variables associated with critically ill patients and describe the standard invasive procedures or treatments used among patients in ICU. Method: A retrospective comparative study which utilized the ICU electronic database. The data of 446 dead patients who have admitted to ICU between January 2014 and December 2016 as a case of sepsis, heart failure or COPD exacerbation were enrolled. Result: Almost of all patients had received intravenous fluid and vasoactive drugs. The mechanical ventilation support and insertion of the indwelling urethral catheter commonly used among patients with critical illnesses;78.3%, 41.3% respectively. One-third of all sepsis and heart failure patients were received CVC during ICU stay;patients with sepsis illness had less hospital length of stay than patients with heart failure and COPD (p Conclusion: We found a reduction in the death number among sepsis, heart failure and COPD patients with move forwards in years, the variety of death rate depends on the type of invasive procedure and treatment performed for each illness, mechanical ventilation support and insertion of indwelling urethral catheter commonly used among patients with critical illnesses. 展开更多
关键词 critical Illness INTENSIVE Care Unit INVASIVE Procedures Chronic OBSTRUCTIVE PULMONARY Disease Heart Failure SEPSIS MORTALITY rate Length of Stay
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