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Mudcake effects on wellbore stress and fracture initiation pressure and implications for wellbore strengthening

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Petroleum Science 2018年第2期15卷 319-334页

作者： Yongcun Feng Xiaorong Li k.E.gray The University of Texas at Austin AustinTXUSA

Although a large volume of mudcake filtration test data is available in the literature, effects of mudcake on wellbore strengthening cannot be quantified without incorporating the data into a stress-analysis model. Traditional models for determining fracture initiation pressure （FIP） either consider a wellbore with an impermeable mudcake or with no mudcake at all. An analytical model considering permeable mudcake is proposed in this paper. The model can predict pore pressure and stress profiles around the wellbore, and consequently the FIP, for different mudcake thickness, permeability, and strength. Numerical examples are provided to illustrate the effects of these mudcake parameters. The results show that a low-permeability mudcake enhances FIP, mainly through restricting fluid seepage and pore pressure increase in the near- wellbore region, rather than by mudcake strength. Fluid loss pressure （FLP） should be distinguished from FIP when a mudcake is present on the wellbore wall. Fracture may occur behind the mudcake at FIP without mudcake rupture. The small effect of mudcake strength on FIP does not mean its effect on FLP is small too. Mudcake strength may play an important role in maintaining integrity of the wellbore once a fracture has initiated behind the mudcake.

关键词： Mudcake Hoop stress Fracture initiation pressure Fluid loss pressure Wellbore strengthening

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焊接无头轧制技术

冶金设备 2000年第4期 38-41页

作者： CLIFFORD k.gray 意大利Techint(德兴)技术公司

阐明近几年开发出来的一种高效、低成本焊接无头轧制新技术,它包括无头轧制和焊接多块小方坯轧制二种技术,并对闪光焊机和二种焊接轧制的优缺点、经济效益和可行性进行了分析和比较 ,表明这是一种改变现有轧制生产方式的一种重大革新。

关键词：无头轧制焊接小方坯轧制闪光对接焊机

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装煤孔盖的隔热

燃料与化工 2000年第2期31卷 105-106页

作者： k.gray 柯华飞英国钢公司道斯莱恩炼焦厂

近年来, 道斯莱恩炼焦厂在返修焦炉炉顶后, 选用了2台新型装煤车和新装煤系统, 使湿煤装炉情况得到了很大改善.然而, 在新装煤车投产后的15个月中, 启炉盖用的电磁铁常因过热而失灵, 维修记录表明, 2台装煤车先后发生10起电磁铁失灵事... 详细信息

近年来, 道斯莱恩炼焦厂在返修焦炉炉顶后, 选用了2台新型装煤车和新装煤系统, 使湿煤装炉情况得到了很大改善.然而, 在新装煤车投产后的15个月中, 启炉盖用的电磁铁常因过热而失灵, 维修记录表明, 2台装煤车先后发生10起电磁铁失灵事故, 其修理费高达14 040英镑, 更换电磁铁耗时101h, 计工人费1616英镑, 总计达15 656英镑.

关键词：炼焦炉装煤车炉盖电磁铁启盖孔盖隔热

Pathological Changes in Andrias davidianus Infected with Chinese Giant Salamander Ranavirus

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Asian herpetological Research 2016年第4期7卷 258-264页

作者： Yi GENG Matthew James gray kaiyu WANG Defang CheN Ping OUYANG Xiaoli HUANG Changliang he Zhijun ZHONG Zexiao YANG College of Veterinary Medicine Sichuan Agricultural University Center for Wildlife health University of Tennessee Department of Aquaculture Sichuan Agricultural University

Chinese giant salamander ranavirus （CGSRV） is an emerging pathogen in captive populations of the Chinese giant salamander （Andrias davidianus）. We processed 140 morbid Chinese giant salamanders from seven captive breeding populations over five years, and describe the disease associated with CGSRV infection. The most common gross signs were significant swelling of the legs and coelomic cavity, erythema of the legs and ventrum in juveniles; cutaneous erosions and ulcerations in adults, particularly the limbs and the head; and marked petechial or ecchymotic hemorrhages of the internal organs, particularly the liver, spleen and kidney. Histological examination showed degeneration, necrosis, and inflammation in many organs, particularly in the organs where hemorrhage was observed. There was evidence of eosinophilic inclusion bodies in degenerated and necrotic cells. We identified virus particles and empty capsids without viral nucleoid in the inclusion bodies using electron microscopy. Virus particles were hexagonal or round shape, and appeared in paracrystalline arrays, aggregates, or singly. All enveloped viral particles were 140-160 nm. Polymerase chain reaction followed by sequencing verified that the virus particles were CGSRV. These results collectively support that CGSRV was the etiologic agent responsible for these mass die-offs of the Chinese giant salamander. The pathology described herein will be useful in diagnosing cases of ranaviral disease caused by CGSRV, and provide evidence that this pathogen is a significant threat to the Chinese giant salamander.

关键词： pathology CGSRV Andrias davidianus ranavirus China

Disability management and rehabilitation for persons with multiple sclerosis

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Neural Regeneration Research 2010年第4期5卷 301-309页

作者： Fary khan Orla gray Department of Medicine University of MelbourneParkville Department of Rehabilitation Medicine Royal Melbourne HospitalParkville

Multiple sclerosis is the commonest cause of chronic neurological disability in young adults. Patients typically have a normal life span, though with accrued time multiple disabilities with a significant impact on quality of life. This article presents the current literature on symptomatic treatment and rehabilitation for persons with multiple sclerosis. A comprehensive multidisciplinary approach addresses the acute, intermediate and long-term medical, psychological and social issues faced by these individuals. Prevention of medical complications, maintenance and restoration of functional independence, addressing psychosocial factors and issues relating to quality of life are integral to the rehabilitation processes.

关键词： multiple sclerosis disability management rehabilitation multidisciplinary effectiveness literature review neurodegenerative disease neural regeneration

The effect of gas phase polydimethylsiloxane surface treatment of metallic aluminum particles： Surface characterization and flow behavior

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Particuology 2017年第1期15卷 92-101页

作者： Bellamarie Ludwia Jennifer L. gray Applied Research Laboratory The Pennsylvania State University North Atherton Street State College PA 16801 USA Materials Research Institute The Pennsylvania State University USA

Aluminum particles were exposed to gaseous polydimethylsiloxane （PDMS） to produce a hydropho- bic surface coating for enhanced flow and fluidity. Surface retention of the intact PDMS was confirmed through infrared and X-ray photoelectron spectroscopy. Transmission electron microscopy was used to image cross-sections of the treated particles and energy dispersive spectroscopy element maps demon- strated the presence of a surface layer consisting of silicon and oxygen. Density measurements provided evidence for improvements in the Hausner ratio and Carr index of the PDMS-treated aluminum, indicating a reduction in inter-particulate cohesion through increased bulk density. Stability, compressibility, shear, aeration, and permeability of the particles were assessed by powder rheometer. The compressibility was reduced by approximately 32% following surface treatment, revealing a reduction in void space, while Mohr＇s circle analysis and shear testing determined that the extrapolated cohesion value was reduced by approximately 53% and the flow factor at 6 kPa was doubled. Aeration testing showed that the air velocity required to obtain a fluidized bed was on the order of 0.35 mm/s for the treated powder, whereas the raw powder could not be uniformly fluidized. PDMS may be a viable option for the large-scale treatment of aluminum powder for flow applications.

关键词： Aluminum powder Polydimethylsiloxane X-ray photoelectron spectroscopy Diffuse reflectance infrared Fourier transform spectroscopy Flowability FT4 powder rheometer

Aphids and their transmitted potato viruses: A continuous challenges in potato crops

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Journal of Integrative Agriculture 2020年第2期19卷 367-375页

作者： XU Yi stewart M.gray Department of Plant Pathology Nanjing Agricultural UniversityNanjing 210095P.R.China Section of Plant Pathology and Plant-Microbe Biology School of Integrated Plant ScienceCornell UniversityIthacaNY 14850USA Emerging Pest and Pathogens Research Unit United States Department of Agriculture–Agricultural Research ServiceIthacaNY 14850USA

Aphid is one of the most destructive insect pests on cultivated plants in temperate *** piercing-sucking mouthparts and phloem feeding behavior directly damage crops and deplete plant ***(Solanum tuberosum L.)is one of the most important food sources on the planet,and several aphid species,e.g.,Myzus persicae(Sulzer)(green peach aphid)and Macrosiphum euphorbiae(Thomas)(potato aphid)(hemiptera:Aphididae)colonize potato and transmit several economically important ***-transmitted potato viruses have been emerging all over the world as a very serious problem in potato production,inducing a wide variety of foliar and tuber symptoms,leading to severe yield reduction and loss of tuber *** this review,recent advances in understanding the interactions of potato viruses with their hosts,aphid vectors and the environment are described.

关键词： aphids virus potato vector transmission

Evolution of Microalloyed Linepipe steels With Particular Emphasis on the “Near Stoichiometry” Low Carbon,0.10 Percent Niobium “HTP” Concept

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Journal of Iron and steel Research International 2011年第S1期18卷 652-657页

作者： gray J.Malcolm Microalloyed steel Institute Inc. 5100 Westheimer Ste 540HoustonTX 77056 USA

Microalloyed linepipe steels were first introduced in 1959 at strength levels around 52-60 ksi [1] [2].The steels were generally strengthened by niobium or vanadium used *** strengths levels increased to X-70 in the early 1970’s niobium and vanadium were used in combination and controlled rolling was introduced on a broad *** strengths decrease tolerance for impurities and non-metallic inclusions which required improved steelmaking ***,carbon,and nitrogen were reduced and continuous casting was increasingly applied which required improved ladle refining and deoxidation ***-molybdenum steels were introduced by IPSCO in 1972 [3] and by Italsider in 1974 [4].steels with higher niobium contents were also introduced in the early 1970’s but available steelmaking technologies limited the use of optimum niobium to carbon ratios,*** approaching *** the steels benefited from the effect of niobium in retarding austenite recrystallization at relatively high rolling temperatures and they developed attractive combinations of strength and toughness in old manufacturing facilities using simple (relaxed) rolling *** in the price of molybdenum and vanadium in the past decade and expanded application of API Grade X-80 linepipe,have led to more widespread use of niobium contents up to 0.11 percent,in combination with 0.02-0.03 percent carbon (near stoichiometry) thus maximizing the effects of solute niobium during rolling,in lowering transformation temperature,and thereby reducing reliance on other alloying,often expensive,*** history of these developments will be presented and applications of the concept will be summarized.

关键词： HTP Low Carbon,0.10 Percent Niobium Near Stoichiometry Evolution of Microalloyed Linepipe steels With Particular Emphasis on the Concept

Multiple stressors lead to complex responses in reproductive behaviors in an African cichlid

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Current Zoology 2024年第6期70卷 821-832页

作者： Bethany Williams Lauren Pintor Suzanne gray Department of Biology University of Missouri-1 University BlvdSt.LouisSt.LouisMO 63121USA

Exposure to multiple environmental stressors is a common occurrence that can affect organisms in predictable or unpredictable *** and turbidity in aquatic environments are 2 stressors that can affect reproductive behaviors by altering energy availability and the visual environment,*** we examine the relative effects of population and the rearing environment(oxygen concentration and turbidity)on reproductive *** reared cichlid fish(the Egyptian mouthbrooder,Pseudocrenilabrus multicolor)from 2 populations(a swamp and river)until sexual maturity,in a full factorial design(hypoxic/normoxic×clear/turbid)and then quantified male competitive and courtship behaviors and female preference under their respective rearing ***,we found that the rearing environment was more important than population for determining behavior,indicating there were few heritable differences in reproductive behavior between the 2 ***,males in the hypoxic rearing treatment performed more competitive and courtship *** turbid conditions,males performed fewer competitive and courtship *** predicted that females would prefer males from their own ***,under the hypoxic and turbid combination females from both populations preferred males from the other *** results suggest that reproductive behaviors are affected by interactions among male traits,female preferences,and environmental conditions.

关键词： cichlid competition hypoxia mate choice turbidity