Testing final closure time of the Paleo-Asian Ocean along the Solonker suture by a transition of compressional and extensional setting

The giant Central Asian Orogenic Belt is an extensive accretionary orogen,of which the Solonker suture,as a major regional suture,coincides closely with an early Permian paleobiogeographical boundary.This suture is considered to mark the location of the final closure of the Paleo-Asian Ocean between the North China Craton and the Mongolian Terrane.Although the closure time of the Paleo-Asian Ocean along the Solonker suture has generally been regarded as Late Permian-Early Triassic,uncertainty remains because of a lack of typical collisionrelated features(e.g.,high-grade regional metamorphism and well-developed fold-thrust structures)and a scarcity of outcrops.The present study reports Early Permian foliated gabbros and dikes(288-275 Ma)and Middle-Late Permian undeformed layered gabbros,strongly peraluminous granites,and I-type granites(265-254 Ma)in the Xinhure area along the northern margin of the North China Craton.The Early Permian foliated intrusions have a subduction-related geochemical signature and were derived from partial melting of lithospheric mantle modified by subduction-related melts or fluids at the active margin of the North China Craton.In contrast,the Late Permian undeformed layered gabbros and strongly peraluminous granites were derived from partial melting of lithospheric mantle and middle-upper crust,respectively,triggered by asthenospheric upwelling.Therefore,a transition from an end-compressional to an extensional environment according to a transition from collision termination to postcollision of the North China Craton and Mongolian Terrane may have occurred between 275 Ma and 262 Ma.This time span can be considered as the final closure time of the Paleo-Asian Ocean along the Solonker suture.

New Evidence of Detrital Zircon Ages for the Final Closure Time of the Paleo-Asian Ocean in the Eastern Central Asian Orogenic Belt(NE China)

Objective The NE China is located in the eastern segment of the Central Asian Orogenic Belt（CAOB）,which is a large accretionary orogen between the Siberian Craton and the North China Craton（NCC）.Many researches have discussed about the evolution of the Paleo-Asian Ocean（PAO）in the eastern CAOB.However,

Randomized clinical trial comparing skin closure with tissue adhesives vs subcuticular suture after robotic urogynecologic procedures

BACKGROUND Skin closure techniques during minimally-invasive gynecologic surgery is largely based on surgeon preference.The optimum technique would theoretically be safe,rapid,inexpensive,and result in good cosmetic appearance.Cyanoacrylate tissue adhesive(Dermabond)may be a comparable and safe option for port site closure as compared with subcuticular suture.In this randomized clinical trial,we hypothesized that operative time for skin closure would be less than subcuticular suture during robotic urogynecologic procedures.AIM To compare skin closure during robotic urogynecologic surgeries for tissue adhesives and subcuticular suture.METHODS Fifty female subjects>18 years of age undergoing robotic urogynecologic procedures were randomized to have port site closure with either cyanoacrylate tissue adhesive(n=25)or subcuticular suture(n=25).All procedures and postoperative evaluations were performed by the same board certified Female Pelvic Medicine and Reconstructive Surgeon.Incisional closure time was recorded.Each subject was followed for 12-wk postoperatively.Incision cosmesis was evaluated using the Stony Brook Scar Evaluation Scale.RESULTS A total of 47 subjects(cyanoacrylate group,n=23;suture group,n=24)completed the 12-wk postoperative evaluation.Closure time was significantly less(P<0.0005)using cyanoacrylate tissue adhesive(5.4±2.0 min)than subcuticular suture(24.9±5.6 min).Cosmesis scores were significantly higher in the cyanoacrylate tissue adhesive group than subcuticular suture(P=0.025).No differences were found between bleeding,infection,or dehiscence(P=1.00,P=0.609,P=0.234,respectively).No statistical demographical differences existed between the two study arms.CONCLUSION Our study supported our original hypothesis that cyanoacrylate tissue adhesive for port site closure during robotic urogynecolgic procedures uses less time than with subcuticular suture.Our study also supports that tissue adhesive is comparable to cosmetic outcome while not jeopardizing rates of bleeding,infection,or dehiscence.

Atmospheric disturbance on the gas explosion in closed fire zone

In order to avoid serious safety accidents caused by closed fire zone,based on the continuous monitoring of atmospheric pressure at different monitoring points in multiple mines,the atmospheric pressure fluctuation model and the air leakage model were established and analyzed.The change law with time of oxygen concentration and gas concentration in the fire zone were obtained due to atmospheric disturbances under the influence of different pressure difference,volume and size of fire area,wind resistance,gas emission,sealing moments,etc.so as to evaluate the explosion risk of a closed fire zone.Research showed that the mine atmosphere fluctuates with the atmosphere of ground,and the pressure difference between the inner and outer sides of the enclosed fire zone is affected by the periodic fluctuation of atmosphere,which has about 16-h cosine fluctuation and approximate 8-h fixed value.Compared with the fire zone with poor sealing quality,good sealing fire zone has better resistance to atmospheric disturbance.The reduction of oxygen concentration in the inner side of a well-sealed fire zone mainly depends on the dilution of methane,which is more likely to accumulate and rise rapidly.And the fire zone with poor sealing quality is easy to be interfered.The inner oxygen concentration and gas concentration are easily affected by the absolute gas emission and the air leakage in the fire zone.Fire zone with small wind resistance and small volume is especially obvious.At the initial stage of the closed fire zone it's very possible to happen explosion.The time duration of explosion danger varies under different conditions,and the atmospheric disturbance may lead to repeated explosions in some cases.It's suggested to take some methods to avoid explosions according to the real-time situation,closure time,oxygen concentration and gas concentration of fire zone.

In-service performance of emergency shutdown valves and dependent operational relationships in the offshore oil and gas industry

Industrial process plants use emergency shutdown valves(ESDVs)as safety barriers to protect against hazardous events,bringing the plant to a safe state when potential danger is detected.These ESDVs are used extensively in offshore oil and gas processing plants and have been mandated in the design of such systems from national and international standards and legislation.This paper has used actual ESDV operating data from four mid/late life oil and gas production platforms in the North Sea to research operational relationships that are of interest to those responsible for the technical management and operation of ESDVs.The first of the two relationships is between the closure time(CT)of the ESDV and the time it remains in the open position,prior to the close command.It has been hypothesised that the CT of the ESDV is affected by the length of time that it has been open prior to being closed(Time since the last stroke).In addition to the general analysis of the data series,two sub-categories were created to further investigate this possible relationship for CT and these are“above mean”and“below mean”.The correlations(Pearson's based)resulting from this analysis are in the“weak”and“very weak”categories.The second relationship investigated was the effect of very frequent closures to assess if this improves the CT.ESDV operational records for six subjects were analysed to find closures that occurred within a 24 h period of each other.However,no discriminating trend was apparent where CT was impacted positively or negatively by the frequent closure group.It was concluded that the variance of ESDV closure time cannot be influenced by the technical management of the ESDV in terms of scheduling the operation of the ESDV.