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Influence of Incomplete Soil Plugs on Bearing Capacities of Bucket Foundations in Clay
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作者 LI Hui-shan LIU Run +1 位作者 YANG Xu LIAN Ji-jian 《China Ocean Engineering》 SCIE EI CSCD 2024年第1期144-155,共12页
Due to the uneven seabed and heaving of soil during pumping,incomplete soil plugs may occur during the installation of bucket foundations,and the impacts on the bearing capacities of bucket foundations need to be eval... Due to the uneven seabed and heaving of soil during pumping,incomplete soil plugs may occur during the installation of bucket foundations,and the impacts on the bearing capacities of bucket foundations need to be evaluated.In this paper,the contact ratio(the ratio of the top diameter of the soil plug to the diameter of the bucket)and the soil plug ratio(the ratio of the soil heave height to the skirt height)are defined to describe the shape and size of the incomplete soil plug.Then,finite element models are established to investigate the bearing capacities of bucket foundations with incomplete soil plugs and the influences of the contact ratios,and the soil plug ratios on the bearing capacities are analyzed.The results show that the vertical bearing capacity of bucket foundations in homogeneous soil continuously improves with the increase of the contact ratio.However,in normally consolidated soil,the vertical bearing capacity barely changes when the contact ratio is smaller than 0.75,while the bearing capacity suddenly increases when the contact ratio increases to 1 due to the change of failure mode.The contact ratio hardly affects the horizontal bearing capacity of bucket foundations.Moreover,the moment bearing capacity improves with the increase of the contact ratio for small aspect ratios,but hardly varies with increasing contact ratio for aspect ratios larger than 0.5.Consequently,the reduction coefficient method is proposed based on this analysis to calculate the bearing capacities of bucket foundations considering the influence of incomplete soil plugs.The comparison results show that the proposed reduction coefficient method can be used to evaluate the influences of incomplete soil plug on the bearing capacities of bucket foundations. 展开更多
关键词 bucket foundation incomplete soil plug uniaxial bearing capacity contact ratio soil plug ratio
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Study on Chrome-free Purging Plugs for Steel Ladles
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作者 Yunpeng ZHOU Wang FENG +2 位作者 Shankha CHATTERJEE Andus BUHR Sebastian KLAUS 《China's Refractories》 CAS 2024年第2期41-47,共7页
Purging plug refractories in China typically contain around 3 mass% of super-fine chromium oxide in the matrix in order to improve the performance of the purging plugs, primarily, slag corrosion and wear resistance. A... Purging plug refractories in China typically contain around 3 mass% of super-fine chromium oxide in the matrix in order to improve the performance of the purging plugs, primarily, slag corrosion and wear resistance. Alternatives to chromium oxide containing refractories have gained interest due to health concerns related to the formation of soluble chromium compounds over long storage periods of refractory wastes. Super-ground reactive alumina can replace chromium oxide in purging plug refractories and this paper discussed the new reactive alumina E-SY 88 in comparison to chromium oxide in a typical purging plug castable. The mixing behaviour, wet castable properties, as well as cured, dried, and fired properties at different temperatures up to 1 600 ℃ were compared. In addition, the hot modulus of rupture, creep behaviour, thermal shock resistance and slag corrosion resistance were tested. The microstructure after slag corrosion was investigated by SEM. The results prove that E-SY 88 is an economically viable technical alternative to chromium oxide in purging plug refractories. 展开更多
关键词 purging plug alumina-spinel castable WORKABILITY chromium-free thermal shock resistance
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Anal plugs and retrograde colonic irrigation are helpful in fecal incontinence or constipation 被引量:4
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作者 Marcel Cazemier Richelle JF Felt-Bersma Chris JJ Mulder 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第22期3101-3105,共5页
AIM: To evaluate the feasibility, clinical effect and predicting factors for favorable outcome of treatment with anal plugs in fecal incontinence and retrograde colonic irrigation (RCI) in patients with fecal incon... AIM: To evaluate the feasibility, clinical effect and predicting factors for favorable outcome of treatment with anal plugs in fecal incontinence and retrograde colonic irrigation (RCI) in patients with fecal incontinence or constipation.METHODS: Patients who received treatment with an anal plug or RCI between 1980 and 2005 were investigated with a questionnaire.RESULTS: Of the 201 patients (93 adults, 108 children), 101 (50%) responded. Adults: anal plugs (8), five stopped immediately, one stopped after 20 mo and two used it for 12-15 too. RCl (40, 28 fecal incontinence, 12 constipation), 63% are still using it (mean 8.5 years), 88% was satisfied. Younger adults (〈 40 years) were more satisfied with RCI (94 % vs 65%, P = 0.05). Children: anal plugs (7), 5 used it on demand for an average of 2.5 years with satisfactory results, one stopped immediately and one after 5 years. RCI (26 fecal incontinence, 22 constipation), 90% are still using it (mean time 6.8 years) and felt satisfied. Children tend to be more satisfied (P = 0.001). Besides age, no predictive factors for success were found. There was no difference in the outcome between patients with fecal incontinence or constipation.CONCLUSION: RCI is more often applied than anal plugs and is helpful in patients with fecal incontinence or constipation, especially for younger patients. Anal plugs can be used incidentally for fecal incontinence, especially in children. 展开更多
关键词 Fecal incontinence CONSTIPATION Retrograde colonic irrigation Anal plug
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Transport of Wetting and Nonwetting Liquid Plugs in a T-shaped Microchannel 被引量:3
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作者 雍玉梅 李莎 +1 位作者 杨超 尹小龙 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2013年第5期463-472,共10页
The transport of liquid plugs in microchannels is very important for many applications such as in medical treatments in airways and in extraction of oil from porous rocks.A plug of wetting and non-wetting liquids driv... The transport of liquid plugs in microchannels is very important for many applications such as in medical treatments in airways and in extraction of oil from porous rocks.A plug of wetting and non-wetting liquids driven by a constant pressure difference through a T-shaped microchannel is studied numerically with lattice Boltzmann(LB) method.A two-phase flow LB model based on field mediators is built.Three typical flow patterns(blocking,rupture and splitting flow) of plug flow are obtained with different driving pressures.It is found that it becomes difficult for a plug with short initial plug length to leave the microchannel;the flow pattern of plug transport varies with the contact angle,especially from wetting to nonwetting;with the increase of interfacial tension,the front interface of plug moves faster;the front and rear interfaces of the plug with small viscosity ratio move faster in the microchannel than those of the plug with large viscosity ratio.The study is helpful to provide theoretical data for the design and scale-up of liquid-liquid reactors and separators. 展开更多
关键词 lattice Boltzmann method plug flow contact angle interfacial tension MICROCHANNEL
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Effect of mechanical vibration process parameters on the cement plugs properties for abandoned wells 被引量:1
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作者 Hang-Ming Liu Yang-Ye He +6 位作者 Ji-Fang Wan Lin Chen Xian-Zhong Yi Yuan-Hua Zhou Yu-Xian He Xiang-Gui Ming Lu Ren 《Petroleum Science》 SCIE EI CAS CSCD 2023年第4期2428-2441,共14页
A high-quality plug of the abandoned wellbore is considered an essential technical aspect of the oil and gas well abandonment technology system. This paper presents a method of active mechanical excitation to enhance ... A high-quality plug of the abandoned wellbore is considered an essential technical aspect of the oil and gas well abandonment technology system. This paper presents a method of active mechanical excitation to enhance the quality of wellbore plug barriers. An indoor simulation platform is developed, and the effects of different combinations of vibration frequency, amplitude and duration on the properties of the wellbore plug cement material are investigated. It is observed that the optimal combination of excitation parameters occurs at a vibration frequency of 15 Hz, a vibration time of 6 min, and a vibration amplitude of 3 mm. Compared with the condition without the vibration process, the cementing strength, compressive strength, and tensile strength of wellbore cement plug with the optimal mechanical vibration process could increase by 51%, 38% and 20%, respectively, while the porosity decreases by 5%. As determined by scanning electron microscopy of the set cement's microstructure, mechanical vibration effectively eliminates internal porosity and improves the set cement's density. The optimal excitation parameters obtained from the test can guide the design of the vibration plugging tool. The designed vibration plugging tool is simulated in the near field. The cement plug cementation quality tester tests the vibrating and non-vibrating samples, and the cementation ratio is calculated. The test results show that the average cementation ratio of vibrating samples is 0.89375, and that of non-vibrating samples is 0.70625, and the cementation quality is improved by 27%. It is concluded that it not only provides essential data for the design of mechanical vibration plug apparatus, on-site vibration plugs, and the development of operational specifications for vibration plugs, but also provides solid engineering guidance. 展开更多
关键词 plugging and abandonment Cement plug VIBRATION Mechanical properties MICROSTRUCTURE
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Progress and Developing Trend of Purging Plugs for Refining Ladle 被引量:1
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作者 ZHANG Ju SUN Xiaogai +1 位作者 JIA Quanli WU Ran 《China's Refractories》 CAS 2014年第2期39-42,共4页
Damage reasons of purging plugs for refining ladle and research progress on thermal shock resistance of corundum- spinel purging plugs were summarized. Research achievements and application results of nonoxides bonded... Damage reasons of purging plugs for refining ladle and research progress on thermal shock resistance of corundum- spinel purging plugs were summarized. Research achievements and application results of nonoxides bonded corundum purging plugs for refining ladle were briefly reviewed. The further research and developing trend of purging plugs was proposed. 展开更多
关键词 purging plugs corundum - spinel nonox-ides thermal shock resistance refining ladle
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Texture,composition and properties of plugs formed by carbon dioxide hydrate and wax 被引量:1
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作者 SKIBA Sergey SAGIDULLIN Aleksey +2 位作者 SHAPOVALOVA Alexandra STRELETS Larisa MANAKOV Andrey 《Petroleum Exploration and Development》 CSCD 2021年第6期1462-1470,共9页
Gas hydrates and wax are the major flow assurance problems for the transportation of produced hydrocarbons through pipelines.However,in most research works both these two problems are studied separately.Although simul... Gas hydrates and wax are the major flow assurance problems for the transportation of produced hydrocarbons through pipelines.However,in most research works both these two problems are studied separately.Although simultaneous precipitation or deposition of these compounds in pipelines can lead to different mitigation/prevention strategies,the investi-gations in which both these problems are considered simultaneously appeared only recently.There is no information in the literature on the texture/composition and features of decomposition process of mixed wax/hydrate plugs.At the same time,this information could be useful to understand how to treat the problem of formation of these plugs.In this work,three wax/gas hydrate plugs were collected at quasi-static conditions from a water-in-oil emulsion to study their texture,composition and the features of decomposition process.Powder X-ray diffraction and IR(infrared spectroscopy)analyses showed that the plugs consisted of wax and gas hydrate.Thermovolumetric and DSC(Differential Scanning Calorimetry)experiments showed that the main part of gas hydrate in the plugs at the ambient pressure started to decompose at about 268 K.This temperature was higher than the equilibrium temperature of carbon dioxide hydrate at this pressure,indicating that the gas hydrate in the plugs could be effectively preserved at temperatures below the ice melting point(273.2 K).It was found through observation of the hydrate decomposition process in the plugs under the microscope that the gas in the samples released in small bubbles,while the hydrate particles were not visible at this magnification,indicating that the hydrate was indeed highly dispersed in the samples.A residual wax was jelly-like after decomposition of hydrate in all the cases.Rheological experiments showed that the plugs residues after decomposition of the hydrates had higher yield points and viscosities than the initial waxy crude oil origi-nally used for the experiments. 展开更多
关键词 carbon dioxide hydrate hydrate/wax plug plug texture hydrate decomposition
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Observation of the effect of cleaning the smear layer and tubule plugs with SEM 被引量:1
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作者 YU Dan-ni1,DONG Ya-li2 1 Department of stomatology of the 2nd Hospital of Tianjin Medical University,Tianjin 300211,China 2 The Electron Microscope Center of Tianjin Medical University, Tianjin 300070,China 《Chinese Journal of Biomedical Engineering(English Edition)》 2001年第1期44-46,共3页
To clean out the smear layer on teeth surface, and protect the teeth medulla, the experiment applied the study observing the cleanup of six groups of surface smear layer of dental caries and the tubule plugs reserving... To clean out the smear layer on teeth surface, and protect the teeth medulla, the experiment applied the study observing the cleanup of six groups of surface smear layer of dental caries and the tubule plugs reserving effect after using of different cavity cleansers with the help of SEM. The result implied that both the acidic preparations and chelator could clean out the smear layer on teeth surface in some way, but the later one could also reserve partial tubule plugs, which reduce the stimulation to the teeth medulla. So the chelator is better cleansers in clinical use. 展开更多
关键词 SEM SMEAR layer TUBULE plugs CAVITY cleansers
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Optimization and Application of Corundum-spinel Purging Plugs for Refining Ladles
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作者 YU Lingyan YU Xingguo ZHANG Xin 《China's Refractories》 CAS 2015年第4期39-41,共3页
Corundum - spinel purging plugs were optimized through adjusting the formulation and the particle size composition of starting materials to prolong the service life of purging plugs for a 60 t refining ladle in a stee... Corundum - spinel purging plugs were optimized through adjusting the formulation and the particle size composition of starting materials to prolong the service life of purging plugs for a 60 t refining ladle in a steel plant. Th.e optimized formulatioa is 30 mass% tabular corundum (6 - 3 mm ) , 20 mass% tabular corundum (3-1 ram), 22 mass% tabular corundum (1 -0.5 ram) + sintered spinel, 28% tabular corundum fines (0. 045 mm) + fused spinel (0. 045 mm) + bimodal α-Al2O3 micropowder + Secar71 cement. The on-site results show that the plug can achieve an obviously long service life of 18 cycles, saving cost greatly. 展开更多
关键词 ladles purging plugs SLIT physical properties
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Effects of Different Progesterone Plugs on Estrous Control in Ewe
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作者 WU Hongda 《Journal of Northeast Agricultural University(English Edition)》 CAS 2009年第2期54-57,共4页
In breeding season and non-breeding season, the effects of three kinds of progesterone plugs on estrous control in ewes were studied. Meanwhile, the advantages and the disadvantages of the progesterone plugs were anal... In breeding season and non-breeding season, the effects of three kinds of progesterone plugs on estrous control in ewes were studied. Meanwhile, the advantages and the disadvantages of the progesterone plugs were analyzed. The results showed that there were no significant difference among three progesterone plugs on modulating the ewes' estrus and pregnancy, and affecting estrous rate and fecundation rate (P〉0.05). It was observed that the progesterone plug produced by Animal Husbandry Research Center of Heilongjiang Academy of Agricultural Sciences could modulate the ewes' estrus and pregnancy effectively, and the low cost and convenience in operation made it popularize in the reproducation of sheep widely. 展开更多
关键词 progesterone plug estrous modulation estrous rate fecundation rate
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Amplatzer Plugs versus Coil Embolization of the Hypogastric Artery Prior to Endovascular Aortic Aneurysm Repair: Differences in Quality of Life
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作者 Luluel Khan Dheeraj K. Rajan +1 位作者 Kong T. Tan Thomas F. Lindsay 《Open Journal of Radiology》 2011年第2期38-44,共7页
Purpose: To determine if there were differences in quality of life (QOL) within the first year following EVAR for patients undergoing internal iliac embolization depending on the type of device used. Methods: Patients... Purpose: To determine if there were differences in quality of life (QOL) within the first year following EVAR for patients undergoing internal iliac embolization depending on the type of device used. Methods: Patients who underwent endovascular AAA repair were identified using a Vascular surgery database at a tertiary care center from 2002-2008. The Radiology Information System and Image Viewer were then used to identify patients who underwent preprocedural embolization prior to endovascular aneurysm repair. Nine patients had embolization with nester coils, 9 had embolization with the amplatzer vascular plug, a type of nitinol based self expanding device. Another group of 8 patients who did not undergo preprocedural embolization was used as a comparator group. These patients were contacted via telephone and answered questions regarding QOL post procedure. The Australian Vascular QOL was the tool used to measure QOL. Differences in QOL were tabulated between the groups of patients. Results: Of the 9 patients who underwent embolization with amplatzer plug, the median QOL score was 60 (p value 0.575), the median QOL for the nester coil group was 52.5 and the comparator group was 58. Separate analysis was done dividing patients into two groups, with and without comorbidities without statistical significance. Conclusion: Patients who underwent preprocedural embolization using amplatzer plugs compared to coils had higher overall QOL scores although the difference was not significant. 展开更多
关键词 AMPLATZER plug COIL EMBOLIZATION EVAR AAA
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Donor's site evaluation after restoration with autografts or synthetic plugs in rabbits
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作者 Konstantinos S Intzoglou Dimitrios S Mastrokalos +3 位作者 Dimitrios S Korres Kleo Papaparaskeva Dimitrios Koulalis George C Babis 《World Journal of Orthopedics》 2014年第4期550-556,共7页
AIM: To investigate donor site's area histological and immunohistochemical knee cartilage appearances after resurfacing iatrogenic defects with biosynthetic plugs orautografts. METHODS: Thirty New Zealand White ra... AIM: To investigate donor site's area histological and immunohistochemical knee cartilage appearances after resurfacing iatrogenic defects with biosynthetic plugs orautografts. METHODS: Thirty New Zealand White rabbits were used in this study. A full-thickness cylindrical defect of 4.5 mm(diameter) × 7 mm(depth) was created with a hand drill in the femoral groove of every animal. In Group A(n = 10) the defect of the donor site was re-paired with a biosynthetic osteochondral plug, in Group B(n = 10) with an osteochondral autograft, while in Group C(control group of 10) rabbits were left untreated. RESULTS: Twenty-four weeks postoperatively, smooth articular cartilage was found macroscopically in some trocleas' surfaces; in all others, an articular surface with discontinuities was observed. Twenty-eight out of 30 animals were found with predominantly viable chondrocytes leaving the remaining two-which were found only in the control group- with partially viable chondrocytes. However, histology revealed many statistical differences between the groups as far as the International Cartilage Repair Society(ICRS) categories are concerned. Immunofluoresence also revealed the presence of collagen Ⅱ in all specimens of Group B, whereas in Group A collagen Ⅱ was found in less specimens. In Group C collagen Ⅱwas not found. CONCLUSION: The matrix, cell distribution, subchondral bone and cartilage mineralization ICRS categories showed statistically differences between the three groups. Group A was second, while group B received the best scores; the control group got the worst ICRS scores in these categories. So, the donor site area, when repairing osteochondral lesions with autografting systems, is better amended with osteochondral autograft rather than bone graft substitute implant. 展开更多
关键词 AUTOGRAFTS SYNTHETIC plug OSTEOCHONDRAL defects Rabbit model animal study DONOR site Immunofluoresence HISTOLOGICAL evaluation International CARTILAGE Repair Society score
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Effects of Nano-CaCO_(3)Addition on Properties of Corundum-based Dispersive Purging Plugs
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作者 SU Yuqing ZHU Yening +5 位作者 YU Baisong XI Zijian WEI Juncong TU Junbo ZHANG Houxing WANG Yilong 《China's Refractories》 CAS 2023年第4期28-32,共5页
In order to improve the properties of corundum based dispersive purging plugs,dispersive purging plug specimens were prepared using tabular corundum(1-0.15 and≤0.15 mm)as the aggregates,tabular corundum(≤0.044 mm)an... In order to improve the properties of corundum based dispersive purging plugs,dispersive purging plug specimens were prepared using tabular corundum(1-0.15 and≤0.15 mm)as the aggregates,tabular corundum(≤0.044 mm)andα-Al_(2)O_(3)micropowder(d_(50)=0.6μm)as the matrix,Secar 71 cement as the binder,introducing different amounts of nano-CaCO_(3),casting into shapes,and firing at different temperatures(1200 or 1600℃)for 4 h.The effects of the nano-CaCO_(3) extra-addition(0,0.5%,1.0%,1.5%and 2.0%,by mass)on the consistency of the castables as well as the properties and microstructure of the dispersive purging plug specimens were studied.The results show that:(1)with the fixed water addition,the consistency of the corundum castables decreases as the nano-CaCO_(3)addition increases;(2)with the increasing nano-CaCO_(3)addition,the bulk density of the specimens fired at different temperatures for 4 h decreases,the apparent porosity,the cold strength and the hot modulus of rupture all increase,the gas permeability does not change significantly;(3)the specimens fired at 1600℃ for 4 h have obviously better cold comprehensive performance than those fired at 1200℃for 4 h;(4)when the nano-CaCO_(3)addition is 1.5%,the comprehensive performance of the specimen is the optimal. 展开更多
关键词 dispersive purging plugs CONSISTENCY nano-calcium carbonate
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Isolated Major Aortopulmonary Collateral Artery Causing Heart Failure: Transcatheter Occlusion of Mapcas Using Amplatzer Vascular Plugs and Amplatzer Piccolo Occluders
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作者 Vakhtang Khelashvili Iuri Fkhkadze +1 位作者 Tengiz Shiryaev Omar Gogia 《World Journal of Cardiovascular Diseases》 2023年第11期701-709,共9页
Major aortopulmonary collateral arteries (MAPCAs) are congenital vessels that arise from the aorta or its first-order branches and are distally connected to the pulmonary arterial vasculature, thereby providing pulmon... Major aortopulmonary collateral arteries (MAPCAs) are congenital vessels that arise from the aorta or its first-order branches and are distally connected to the pulmonary arterial vasculature, thereby providing pulmonary blood flow. MAPCAs are often associated with cyanotic congenital heart disease with decreased pulmonary blood flow. Isolated MAPCAs are rare in patients without congenital heart disease with structurally normal hearts. Sometimes, isolated congenital MAPCAs can occur without any lung disease. Isolated MAPCAs represent the occurrence of collaterals in the absence of underlying heart disease, which commonly presents as heart failure, recurrent respiratory tract infection, and pulmonary artery hypertension. We report a rare case of congestive heart failure in a 6-year-old patient with dual arterial supply to an otherwise normal right lung, with a normal bronchial tree, and a structurally normal heart. The patient was successfully managed by the closure of collaterals by Amplatzer vascular plugs II (AVPII) and Amplatzer Piccolo Occluders. 展开更多
关键词 Isolated Major Aortopulmonary Collateral Artery Amplatzer Vascular plugs Amplatzer Piccolo Occluder Mapcas Transcatheter Closure
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Purging Plugs and Well Blocks for Refining Ladle
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作者 Zhang Xiaohui Chai Junlan 《China's Refractories》 CAS 2009年第2期32-34,共3页
1 Scope This standard specifies the classification, technical requirements, test methods, inspection rules, marking, packing, transportation, storage and quality certificate of purging plugs and well blocks for refini... 1 Scope This standard specifies the classification, technical requirements, test methods, inspection rules, marking, packing, transportation, storage and quality certificate of purging plugs and well blocks for refining ladle. 展开更多
关键词 Purging plugs and Well Blocks for Refining Ladle
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Fracture propagation law of temporary plugging and diversion fracturing in shale reservoirs under completion experiments of horizontal well with multi-cluster sand jetting perforation
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作者 ZOU Yushi LI Yanchao +3 位作者 YANG Can ZHANG Shicheng MA Xinfang ZOU Longqing 《Petroleum Exploration and Development》 SCIE 2024年第3期715-726,共12页
This study conducted temporary plugging and diversion fracturing(TPDF)experiments using a true triaxial fracturing simulation system within a laboratory setting that replicated a lab-based horizontal well completion w... This study conducted temporary plugging and diversion fracturing(TPDF)experiments using a true triaxial fracturing simulation system within a laboratory setting that replicated a lab-based horizontal well completion with multi-cluster sand jetting perforation.The effects of temporary plugging agent(TPA)particle size,TPA concentration,single-cluster perforation number and cluster number on plugging pressure,multi-fracture diversion pattern and distribution of TPAs were investigated.A combination of TPAs with small particle sizes within the fracture and large particle sizes within the segment is conducive to increasing the plugging pressure and promoting the diversion of multi-fractures.The addition of fibers can quickly achieve ultra-high pressure,but it may lead to longitudinal fractures extending along the wellbore.The temporary plugging peak pressure increases with an increase in the concentration of the TPA,reaching a peak at a certain concentration,and further increases do not significantly improve the temporary plugging peak pressure.The breaking pressure and temporary plugging peak pressure show a decreasing trend with an increase in single-cluster perforation number.A lower number of single-cluster perforations is beneficial for increasing the breaking pressure and temporary plugging peak pressure,and it has a more significant control on the propagation of multi-cluster fractures.A lower number of clusters is not conducive to increasing the total number and complexity of artificial fractures,while a higher number of clusters makes it difficult to achieve effective plugging.The TPAs within the fracture is mainly concentrated in the complex fracture areas,especially at the intersections of fractures.Meanwhile,the TPAs within the segment are primarily distributed near the perforation cluster apertures which initiated complex fractures. 展开更多
关键词 shale temporary plugging and diversion fracturing multi-cluster sand jetting perforation distribution of temporary plugging agent fracture propagation law
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Curing kinetics and plugging mechanism of high strength curable resin plugging material
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作者 Jing-Bin Yang Ying-Rui Bai +1 位作者 Jin-Sheng Sun Kai-He Lv 《Petroleum Science》 SCIE EI CAS CSCD 2024年第5期3446-3463,共18页
Lost circulation, a recurring peril during drilling operations, entails substantial loss of drilling fluid and dire consequences upon its infiltration into the formation. As drilling depth escalates, the formation tem... Lost circulation, a recurring peril during drilling operations, entails substantial loss of drilling fluid and dire 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 reaction parameters, the study attests to the fulfillment of the kinetic equation for the urea-formaldehyde resin plugging system. This discerning analysis illuminates the nuanced shifts in the microscopic reaction mechanism of the urea-formaldehyde resin plugging system. Furthermore, the pressure bearing plugging capacity of the resin plugging system for fractures of different sizes is also studied. It is found that the resin plugging system can effectively resident in parallel and wedge-shaped fractures of different sizes, and form high-strength consolidation under certain temperature conditions. The maximum plugging pressure of resin plugging system for parallel fractures with outlet size 3 mm can reach 9.92 MPa, and the maximum plugging pressure for wedge-shaped fractures with outlet size 5 mm can reach 9.90 MPa. Consequently, the exploration and application of urea-formaldehyde resin plugging material precipitate a paradigm shift, proffering novel concepts and methodologies in resolving the practical quandaries afflicting drilling fluid plugging. 展开更多
关键词 Urea-formaldehyde resin Rheological property Curing property Curing kinetics plugging mechanism
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Transportation and sealing pattern of the temporary plugging ball at the spiral perforation in the horizontal well section
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作者 Qing-Hai Hu Wan Cheng +2 位作者 Zun-Cha Wang Yu-Zhao Shi Guang-Liang Jia 《Petroleum Science》 SCIE EI CAS CSCD 2024年第5期3288-3297,共10页
Multistage fracturing of horizontal wells is a critical technology for unconventional oil and gas reservoir stimulation. Ball-throwing temporary plugging fracturing is a new method for realizing uniform fracturing alo... Multistage fracturing of horizontal wells is a critical technology for unconventional oil and gas reservoir stimulation. Ball-throwing temporary plugging fracturing is a new method for realizing uniform fracturing along horizontal wells and plays an important role in increasing oil and gas production. However,the transportation and sealing law of temporary plugging balls(TPBs) in the perforation section of horizontal wells is still unclear. Using COMSOL computational fluid dynamics and a particle tracking module, we simulate the transportation process of TPBs in a horizontal wellbore and analyse the effects of the ball density, ball diameter, ball number, fracturing fluid injection rate, and viscosity on the plugging efficiency of TPB transportation. This study reveals that when the density of TPBs is close to that of the fracturing fluid and a moderate diameter of the TPB is used, the plugging efficiency can be substantially enhanced. The plugging efficiency is greater when the TPB number is close to twice the number of perforations and is lower when the number of TPBs is three times the number of perforations.Adjusting the fracturing fluid injection rate from low to high can control the position of the TPBs,improving plugging efficiency. As the viscosity of the fracturing fluid increases, the plugging efficiency of the perforations decreases near the borehole heel and increases near the borehole toe. In contrast, the plugging efficiency of the central perforation is almost unaffected by the fracturing fluid viscosity. This study can serve as a valuable reference for establishing the parameters for temporary plugging and fracturing. 展开更多
关键词 Temporary plugging ball Horizontal well Multistage fracturing Spiral perforation Numerical simulation
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A novel responsive stabilizing Janus nanosilica as a nanoplugging agent in water-based drilling fluids for exploiting hostile shale environments
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作者 Alain Pierre Tchameni Lv-Yan Zhuo +5 位作者 Lesly Dasilva Wandji Djouonkep Robert Dery Nagre Lu-Xin Chen Lin Zhao Chao Ma Bin-Qiang Xie 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期1190-1210,共21页
Thermo-responsive nanocomposites have recently emerged as potential nanoplugging agents for shale stabilization in high-temperature water-based drilling fluids(WBDFs). However, their inhibitory properties have not bee... Thermo-responsive nanocomposites have recently emerged as potential nanoplugging agents for shale stabilization in high-temperature water-based drilling fluids(WBDFs). However, their inhibitory properties have not been very effective in high-temperature drilling operations. Thermo-responsive Janus nanocomposites are expected to strongly interact with clay particles from the inward hemisphere of nanomaterials, which drive the establishment of a tighter hydrophobic membrane over the shale surface at the outward hemisphere under geothermal conditions for shale stabilization. This work combines the synergistic benefits of thermo-responsive and zwitterionic nanomaterials to synchronously enhance the chemical inhibitions and plugging performances in shale under harsh conditions. A novel thermoresponsive Janus nanosilica(TRJS) exhibiting zwitterionic character was synthesized, characterized,and assessed as shale stabilizer for WBDFs at high temperatures. Compared to pristine nanosilica(Si NP)and symmetrical thermo-responsive nanosilica(TRS), TRJS exhibited anti-polyelectrolyte behaviour, in which electrolyte ions screened the electrostatic attraction between the charged particles, potentially stabilizing nanomaterial in hostile shaly environments(i.e., up to saturated brine or API brine). Macroscopically, TRJS exhibited higher chemical inhibition than Si NP and TRS in brine, prompting a better capability to control pressure penetration. TRJS adsorbed onto the clay surface via chemisorption and hydrogen bonding, and the interactions became substantial in brine, according to the results of electrophoretic mobility, surface wettability, and X-ray diffraction. Thus, contributing to the firm trapping of TRJS into the nanopore structure of the shale, triggering the formation of a tight hydrophobic membrane over the shale surface from the outward hemisphere. The addition of TRJS into WBDF had no deleterious effect on fluid properties after hot-treatment at 190℃, implying that TRJS could find potential use as a shale stabilizer in WBDFs in hostile environments. 展开更多
关键词 Janus nanosilica Thermo-responsive copolymer Anti-polyelectrolyte effect Shale stabilizer Inhibition plugging Drilling fluid
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Feasibility of Plug Production Utilizing Digestate from Home-Waste to Energy Systems (H-WEF)
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作者 Rory Elijah Dunn Paige Ann Carroll +5 位作者 Seneshaw Tsegaye Xiusheng Yang John L. Griffis Galen Papkov Sarah Bauer Ankit Kumar Singh 《Agricultural Sciences》 2024年第10期1147-1161,共15页
The integration of sustainable technologies in waste management systems has become imperative in addressing the escalating challenges of agricultural productivity and sustainability. Plugs are essential when starting ... The integration of sustainable technologies in waste management systems has become imperative in addressing the escalating challenges of agricultural productivity and sustainability. Plugs are essential when starting crop production in controlled environment agriculture (CEA) setups and greenhouses. Horticultural crops such as vegetables, fruiting, and ornamental plants that utilize plugs have demonstrated higher success rates, healthier plants, and higher total yields. The APS Laboratory for Sustainable Agriculture explored the innovative utilization of digestate from the Home Water-Energy-Food Systems (H-WEF). The H-WEF system converts household food waste into biogas, electricity, and nutrient-rich digestate. The digestate from the H-WEF system was used to produce agricultural plugs, presenting a novel approach to circular resource utilization. We carried out the growth of Rex Butterhead Lettuce Latuca sativa plugs with 1) control system (synthetic fertilizer) and seven different treatments, 2) 5% Digestate—95% RO Water (5D–95RO);3) 10% Digestate—90% RO Water (10D–90RO);4) 15% Digestate—85% RO Water (15D–85RO);5) 20% Digestate—80% RO Water (20D–80RO);6) 25% Digestate—75% RO Water (25D–75RO);7) 30% Digestate—70% RO Water (30D–70RO);8) 35% Digestate—65% RO Water (35D–65RO). The plugs were cultivated for 15 days in a controlled environment until two leaves had developed after the cotyledon. After 15 days, we collected data on wet weight (g), plug head area (cm2), total leaf area (cm2), total chlorophyll content (mg/cm2), and dry weight (g). In addition, we collected data on the Leaf Area Index (LAI, cm2/cm2) and Specific Leaf Area (SLA, cm2/g). The synthetic fertigation yielded a higher wet weight than the following treatments: 5D–95RO, 10D–90RO, and 35D–65RO. While the 30D–70RO treatment produced a larger plug head than all other treatments. The digestate-based fertilizers were comparable to the synthetic fertilizer at dilutions of 25D–75RO and 30D–70RO. This study underscores the viability of using digestate for plug production, providing crucial insights for growers navigating the challenges of sustainable agricultural practices. 展开更多
关键词 Controlled Environments FERTIGATION plugs DIGESTATE Anaerobic Digestion
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