The weight loss of cement slurry is the main cause of early annular air channeling and accurate experimental evaluation of the law of loss change is the key to achieve compression stability and prevent this undesired ...The weight loss of cement slurry is the main cause of early annular air channeling and accurate experimental evaluation of the law of loss change is the key to achieve compression stability and prevent this undesired phenomenon.Typically,tests on the pressure loss of cement slurry are carried out for temperature smaller than 120°C,and this condition cannot simulate effectively the situation occurring in high temperature wells.For this reason,in this study a series of experimental tests have been conducted considering a larger range of temperatures,different retarders and fluid loss additives.The results show that with an increase in the temperature,the weight loss curve of cement slurry changes from a“two-stage”to a“three-stage”behavior,and the risk of channeling increases accordingly.On increasing the amount of retarder and fluid loss additive,the transition time of cement slurry displays a non-monotonic behavior(it decreases first and then increases).It is found that the optimized retarder and fluid loss additive dosage are 0.2%and 2.5%,respectively.展开更多
This study investigated the relationship among the severity of hearing impairment,vestibular function and balance function in patients with idiopathic sudden sensorineural hearing loss（ISSNHL）.A total of 35 ISSNHL p...This study investigated the relationship among the severity of hearing impairment,vestibular function and balance function in patients with idiopathic sudden sensorineural hearing loss（ISSNHL）.A total of 35 ISSNHL patients（including 21 patients with vertigo） were enrolled.All of the patients underwent audiometry,sensory organization test（SOT）,caloric test,cervical vestibular-evoked myogenic potential（cV EMP） test and ocular vestibular-evoked myogenic potential（o VEMP） test.Significant relationship was found between vertigo and hearing loss grade（P=0.009）,and between SOT VEST grade and hearing loss grade（P=0.001）.The abnormal rate of o VEMP test was the highest,followed by the abnormal rates of caloric and c VEMP tests,not only in patients with vertigo but also in those without vertigo.The vestibular end organs were more susceptible to damage in patients with vertigo（compared with patients without vertigo）.Significant relationship was found between presence of vertigo and SOT VEST grade（P=0.010）.We demonstrated that vestibular end organs may be impaired not only in patients with vertigo but also in patients without vertigo.The cochlear and vestibular impairment could be more serious in patients with vertigo than in those without vertigo.Vertigo does not necessarily bear a causal relationship with the impairment of the vestibular end organs.SOT VEST grade could be used to reflect the presence of vertigo state in the ISSNHL patients.Apart from audiometry,the function of peripheral vestibular end organs and balance function should be evaluated to comprehensively understand ISSNHL.Better assessment of the condition will help us in clinical diagnosis,treatment and prognosis evaluation of ISSNHL.展开更多
The corrosion behaviour of as-cast binary Mg–0.3 Ce,Mg–1.44 Nd,Mg–0.63 Gd and Mg–0.41 Dy(wt%)alloys was investigated in DMEM+10%FBS solution using electrochemical and weight loss tests.The results revealed that th...The corrosion behaviour of as-cast binary Mg–0.3 Ce,Mg–1.44 Nd,Mg–0.63 Gd and Mg–0.41 Dy(wt%)alloys was investigated in DMEM+10%FBS solution using electrochemical and weight loss tests.The results revealed that the alloys with heavy RE elements(Gd and Dy)exhibited the lowest corrosion rate compared to the alloys with light RE elements(Ce and Nd).The cytocompatibility of the Mg–RE alloys was assessed via live/dead straining after 3 and 7 days.The results show that Mg–0.63 Gd alloy is a suitable candidate for biomedical applications.展开更多
Noise presents health and social problems in industrial operations and is mainly related to machinery use.Noise is an important factor that affects work environment,and consequently affects both workers'health and...Noise presents health and social problems in industrial operations and is mainly related to machinery use.Noise is an important factor that affects work environment,and consequently affects both workers'health and efficiency.The US OSHA(Occupational Safety and Health Administration)specify six on-the-j ob physical hazards to health,noise is one of those hazards.There is little or no information about occupational noise exposure of workers within industrial and manufacturing sectors in the Gaza Strip.This is due to the difficulty of conducting noise exposure surveillance in such occupations and the lack of awareness regarding this issue.The objective of the current study is to evaluate the exposure of workers in different industrial sectors to occupational noise using a combined measurement and questionnaire approach The present study was conducted in different utilities industries in the Gaza Strip,in order to evaluate the noise levels at those factories and to develop awareness campaign among those workers.From the obtained data,it can be seen that almost all workers are exposed to higher noise levels than the recommended one by OSHA.Therefore it is necessary to start awareness campaign which informs the workers about noise as an occupational hazard.展开更多
基金The authors gratefully acknowledge the research project from“Research and test on optimization of calculation model for cementing engineering of high temperature and high pressure wells”(Grant No.CQCJ-2020-06).
文摘The weight loss of cement slurry is the main cause of early annular air channeling and accurate experimental evaluation of the law of loss change is the key to achieve compression stability and prevent this undesired phenomenon.Typically,tests on the pressure loss of cement slurry are carried out for temperature smaller than 120°C,and this condition cannot simulate effectively the situation occurring in high temperature wells.For this reason,in this study a series of experimental tests have been conducted considering a larger range of temperatures,different retarders and fluid loss additives.The results show that with an increase in the temperature,the weight loss curve of cement slurry changes from a“two-stage”to a“three-stage”behavior,and the risk of channeling increases accordingly.On increasing the amount of retarder and fluid loss additive,the transition time of cement slurry displays a non-monotonic behavior(it decreases first and then increases).It is found that the optimized retarder and fluid loss additive dosage are 0.2%and 2.5%,respectively.
基金supported by grants from the National Twelfth Five-Year Science and Technology Support Program of China(No.2012BAI12B02)the National Eleventh Five-Year Science and Technology Support Program of China(No.2007BAI18B13)
文摘This study investigated the relationship among the severity of hearing impairment,vestibular function and balance function in patients with idiopathic sudden sensorineural hearing loss（ISSNHL）.A total of 35 ISSNHL patients（including 21 patients with vertigo） were enrolled.All of the patients underwent audiometry,sensory organization test（SOT）,caloric test,cervical vestibular-evoked myogenic potential（cV EMP） test and ocular vestibular-evoked myogenic potential（o VEMP） test.Significant relationship was found between vertigo and hearing loss grade（P=0.009）,and between SOT VEST grade and hearing loss grade（P=0.001）.The abnormal rate of o VEMP test was the highest,followed by the abnormal rates of caloric and c VEMP tests,not only in patients with vertigo but also in those without vertigo.The vestibular end organs were more susceptible to damage in patients with vertigo（compared with patients without vertigo）.Significant relationship was found between presence of vertigo and SOT VEST grade（P=0.010）.We demonstrated that vestibular end organs may be impaired not only in patients with vertigo but also in patients without vertigo.The cochlear and vestibular impairment could be more serious in patients with vertigo than in those without vertigo.Vertigo does not necessarily bear a causal relationship with the impairment of the vestibular end organs.SOT VEST grade could be used to reflect the presence of vertigo state in the ISSNHL patients.Apart from audiometry,the function of peripheral vestibular end organs and balance function should be evaluated to comprehensively understand ISSNHL.Better assessment of the condition will help us in clinical diagnosis,treatment and prognosis evaluation of ISSNHL.
基金supported by the PRFU national project under Grant Agreement No.B00L02UN280120180005
文摘The corrosion behaviour of as-cast binary Mg–0.3 Ce,Mg–1.44 Nd,Mg–0.63 Gd and Mg–0.41 Dy(wt%)alloys was investigated in DMEM+10%FBS solution using electrochemical and weight loss tests.The results revealed that the alloys with heavy RE elements(Gd and Dy)exhibited the lowest corrosion rate compared to the alloys with light RE elements(Ce and Nd).The cytocompatibility of the Mg–RE alloys was assessed via live/dead straining after 3 and 7 days.The results show that Mg–0.63 Gd alloy is a suitable candidate for biomedical applications.
文摘Noise presents health and social problems in industrial operations and is mainly related to machinery use.Noise is an important factor that affects work environment,and consequently affects both workers'health and efficiency.The US OSHA(Occupational Safety and Health Administration)specify six on-the-j ob physical hazards to health,noise is one of those hazards.There is little or no information about occupational noise exposure of workers within industrial and manufacturing sectors in the Gaza Strip.This is due to the difficulty of conducting noise exposure surveillance in such occupations and the lack of awareness regarding this issue.The objective of the current study is to evaluate the exposure of workers in different industrial sectors to occupational noise using a combined measurement and questionnaire approach The present study was conducted in different utilities industries in the Gaza Strip,in order to evaluate the noise levels at those factories and to develop awareness campaign among those workers.From the obtained data,it can be seen that almost all workers are exposed to higher noise levels than the recommended one by OSHA.Therefore it is necessary to start awareness campaign which informs the workers about noise as an occupational hazard.
