A new kind of corrosion resistant steelfor cargo oiltanks（COT）was developed.The influences of finalrolling temperature,cooling rate,and finalcooling temperature on microstructure were investigated.The proper rolling...A new kind of corrosion resistant steelfor cargo oiltanks（COT）was developed.The influences of finalrolling temperature,cooling rate,and finalcooling temperature on microstructure were investigated.The proper rolling process parameters were obtained through multi-pass thermalsimulation test.The finalrolling temperature is about 820 ℃,the finalcooling temperature is about 600 ℃,and the cooling rate should be controlled between 10 ℃/s and 20 ℃/s.Based on the above analysis of the results,three groups of rolling samples by thermo mechanicalcontrolprocess are prepared.The tensile strength,yield strength,and toughness of the corrosion resistant steelare measured,which meet the requirements of DH36 steel,it can instruct the actualrolling production.The corrosion behaviour is also researched by weight loss and electrochemicalimpedance spectroscopic method,and it is found that the steelhas good corrosion resistance performance,the best one is No.3 steel,the corrosion rate of which is about 1/4 of the accepted criterion.展开更多
The significance of cultural awareness in foreign language learning is an issue that earns hot discussion in the both fields of linguistics and instructional science. Being different from others, the observing angle i...The significance of cultural awareness in foreign language learning is an issue that earns hot discussion in the both fields of linguistics and instructional science. Being different from others, the observing angle in this paper lies in how the signal is processed. The four skills of listening, speaking, reading and writing are classified, by ways of signal processing, into two categorizes, namely receptive skills to which listening and reading belong, and productive skills to which speaking and writing belong. By analyzing the signal processing progress occurred in each of the four skills, the author is to argue the functions of cultural awareness in each of these four skills, in order to reinforce the importance of emphasizing cultural awareness in the new standards for English in China.展开更多
The Ojarly gas field,the major supplier of the Project PhaseⅡof the Right Bank of the Amu Darya River,is just small but valuable like a golden bean,although it has good reservoir properties and a high gas production ...The Ojarly gas field,the major supplier of the Project PhaseⅡof the Right Bank of the Amu Darya River,is just small but valuable like a golden bean,although it has good reservoir properties and a high gas production capacity,the occurrence of continuous sharp decline of pressure in the well production shows a great difference from the previous well test program.In view of this,an integrated analysis method was established for the whole gas well production process to discover the three main reasons causing the abnormal well pressure.First,the formation energy and pressure dropped so fast that the wellhead pressure also fell over the period.Second,there was abnormal fluids pressure drop in the wellbore tube and throttling effect might occur in the production tube,so the pressure drop became abnormally increased.Third,due to the abnormally-increasing gas-yield pressure drop and unusually-decreasing gas productivity,the wellhead oil pressure dropped significantly.Also,through dynamic monitoring and in-depth analysis,it is also considered that due to the high density of drilling fluids and well-developed pores and caverns in the reservoirs,more and more barites separated from the fluids would be settled down covering the pay zones,so both the gas-generating capacity and production pressure significantly decreased.On this basis,some technical countermeasures were taken such as re-stimulation of reservoirs,removal of gas-producing channels,increase of seepage capacity,etc.In addition,by use of sand-flushing and acidizing,both the comprehensive skin factor and the production pressure drop were reduced to improve the well gas production capacity and maintain high productivity effectively.This study provides a technical support for long-term sustainable development and production of this gas field.展开更多
In Ethiopian construction projects, schedule delay risk is a predominant issue because it is not properly addressed. Although several studies have been focused on the various effects of risk in construction projects, ...In Ethiopian construction projects, schedule delay risk is a predominant issue because it is not properly addressed. Although several studies have been focused on the various effects of risk in construction projects, limited efforts have been made to investigate the typical and the overall schedule delay risk. In this study, our aim is to detect the typical and overall schedule delay risk throughout the construction project lifecycle, which consists of the pre-construction, construction, and post-construction stages, and compare the stages with each other. Common criteria, sub-criteria, and attributes were developed for all alternatives for the purpose of making a risk decision. The methodology that was followed integrated the multiplecriteria decision-making(MCDM) model of fuzzy analytic hierarchy process comprehensive evaluation(FAHPCE)and the relative important index(RII). Data were collected from 77 participants, who were selected through purposive sampling from different contracting organizations in Ethiopian construction projects by means of questionnaires that were distributed to experienced experts. The findings showed that there is a typical delay risk either in the type or in the level of the different construction activities.Consequently, the most influenced alternative is the construction stage because of the high-risk responsibility,resource, and contract condition related criteria. The postconstruction stage was the second most influenced stage because of the high-risk responsibility-related criteria. The pre-constructed stage was the least influenced stage that consist high-risk criteria of responsibility, resource, and contract condition related. These differences provided noteworthy information about risk mitigation in construction projects by identifying the exact risk level on specific activity to make appropriate decision.展开更多
Comprehension of traffic signs is important to road safety.This review aims to study the extent to which road users in different countries comprehend traffic signs and to identify which ergonomic principles in traffic...Comprehension of traffic signs is important to road safety.This review aims to study the extent to which road users in different countries comprehend traffic signs and to identify which ergonomic principles in traffic sign design can affect the levels of comprehension.We conducted an extensive literature review dealing with comprehension of public traffic signs directed at any road user.We searched Journal articles indexed by Scopus,ScienceDirect,and Web of Science.The search identified 35 articles that assessed the comprehension of 931 traffic signs in 26 countries,including six studies that tested the comprehension of new versus existing traffic signs.Various methods have been implemented to measure traffic signs’comprehension levels and assess traffic sign design’s conformity to different ergonomic principles.Results indicate high variability in the comprehension levels of signs,e.g.,signs such as‘‘Road works”and‘‘No U-turn”are highly comprehended(comprehension levels over 90%),while other signs like‘‘termination of road”are rarely comprehended by road users.Regarding the acceptable comprehension levels,23.1%of the assessed traffic signs achieved levels above 85%;and 53.3%of signs have comprehension levels lower than 67%.On the other hand,twenty-four studies evaluated how traffic signs comply with ergonomic design principles.Incorporating ergonomic principles into the design of traffic signs can improve comprehension levels.However,apart from the familiarity,there is uncertainty about the ergonomic principles that could maximize the comprehension of traffic signs.Efforts should be made to ensure that different populations of road users sufficiently comprehend traffic signs。展开更多
基金Funded by the National Key Technology Research and Development Program of the Ministry of Science and Technology of China during the“12th Five-Year Plan”(No.2011BAE25B03)
文摘A new kind of corrosion resistant steelfor cargo oiltanks（COT）was developed.The influences of finalrolling temperature,cooling rate,and finalcooling temperature on microstructure were investigated.The proper rolling process parameters were obtained through multi-pass thermalsimulation test.The finalrolling temperature is about 820 ℃,the finalcooling temperature is about 600 ℃,and the cooling rate should be controlled between 10 ℃/s and 20 ℃/s.Based on the above analysis of the results,three groups of rolling samples by thermo mechanicalcontrolprocess are prepared.The tensile strength,yield strength,and toughness of the corrosion resistant steelare measured,which meet the requirements of DH36 steel,it can instruct the actualrolling production.The corrosion behaviour is also researched by weight loss and electrochemicalimpedance spectroscopic method,and it is found that the steelhas good corrosion resistance performance,the best one is No.3 steel,the corrosion rate of which is about 1/4 of the accepted criterion.
文摘The significance of cultural awareness in foreign language learning is an issue that earns hot discussion in the both fields of linguistics and instructional science. Being different from others, the observing angle in this paper lies in how the signal is processed. The four skills of listening, speaking, reading and writing are classified, by ways of signal processing, into two categorizes, namely receptive skills to which listening and reading belong, and productive skills to which speaking and writing belong. By analyzing the signal processing progress occurred in each of the four skills, the author is to argue the functions of cultural awareness in each of these four skills, in order to reinforce the importance of emphasizing cultural awareness in the new standards for English in China.
基金CNPC Scientific Research and Technology DevelopmentProject “Key technology research and application for natural gas developmentof 16.5 m^(3) in the Right Bank of the Amu-Darya River, Turkmenistan” (No.:2011E-2505)National Science and Technology Major Project “Demonstra-tion Project of Natural Gas Development in Middle Zone of the Right Bank ofthe Amu-Darya River” (No.: 2011ZX05059).
文摘The Ojarly gas field,the major supplier of the Project PhaseⅡof the Right Bank of the Amu Darya River,is just small but valuable like a golden bean,although it has good reservoir properties and a high gas production capacity,the occurrence of continuous sharp decline of pressure in the well production shows a great difference from the previous well test program.In view of this,an integrated analysis method was established for the whole gas well production process to discover the three main reasons causing the abnormal well pressure.First,the formation energy and pressure dropped so fast that the wellhead pressure also fell over the period.Second,there was abnormal fluids pressure drop in the wellbore tube and throttling effect might occur in the production tube,so the pressure drop became abnormally increased.Third,due to the abnormally-increasing gas-yield pressure drop and unusually-decreasing gas productivity,the wellhead oil pressure dropped significantly.Also,through dynamic monitoring and in-depth analysis,it is also considered that due to the high density of drilling fluids and well-developed pores and caverns in the reservoirs,more and more barites separated from the fluids would be settled down covering the pay zones,so both the gas-generating capacity and production pressure significantly decreased.On this basis,some technical countermeasures were taken such as re-stimulation of reservoirs,removal of gas-producing channels,increase of seepage capacity,etc.In addition,by use of sand-flushing and acidizing,both the comprehensive skin factor and the production pressure drop were reduced to improve the well gas production capacity and maintain high productivity effectively.This study provides a technical support for long-term sustainable development and production of this gas field.
文摘In Ethiopian construction projects, schedule delay risk is a predominant issue because it is not properly addressed. Although several studies have been focused on the various effects of risk in construction projects, limited efforts have been made to investigate the typical and the overall schedule delay risk. In this study, our aim is to detect the typical and overall schedule delay risk throughout the construction project lifecycle, which consists of the pre-construction, construction, and post-construction stages, and compare the stages with each other. Common criteria, sub-criteria, and attributes were developed for all alternatives for the purpose of making a risk decision. The methodology that was followed integrated the multiplecriteria decision-making(MCDM) model of fuzzy analytic hierarchy process comprehensive evaluation(FAHPCE)and the relative important index(RII). Data were collected from 77 participants, who were selected through purposive sampling from different contracting organizations in Ethiopian construction projects by means of questionnaires that were distributed to experienced experts. The findings showed that there is a typical delay risk either in the type or in the level of the different construction activities.Consequently, the most influenced alternative is the construction stage because of the high-risk responsibility,resource, and contract condition related criteria. The postconstruction stage was the second most influenced stage because of the high-risk responsibility-related criteria. The pre-constructed stage was the least influenced stage that consist high-risk criteria of responsibility, resource, and contract condition related. These differences provided noteworthy information about risk mitigation in construction projects by identifying the exact risk level on specific activity to make appropriate decision.
文摘Comprehension of traffic signs is important to road safety.This review aims to study the extent to which road users in different countries comprehend traffic signs and to identify which ergonomic principles in traffic sign design can affect the levels of comprehension.We conducted an extensive literature review dealing with comprehension of public traffic signs directed at any road user.We searched Journal articles indexed by Scopus,ScienceDirect,and Web of Science.The search identified 35 articles that assessed the comprehension of 931 traffic signs in 26 countries,including six studies that tested the comprehension of new versus existing traffic signs.Various methods have been implemented to measure traffic signs’comprehension levels and assess traffic sign design’s conformity to different ergonomic principles.Results indicate high variability in the comprehension levels of signs,e.g.,signs such as‘‘Road works”and‘‘No U-turn”are highly comprehended(comprehension levels over 90%),while other signs like‘‘termination of road”are rarely comprehended by road users.Regarding the acceptable comprehension levels,23.1%of the assessed traffic signs achieved levels above 85%;and 53.3%of signs have comprehension levels lower than 67%.On the other hand,twenty-four studies evaluated how traffic signs comply with ergonomic design principles.Incorporating ergonomic principles into the design of traffic signs can improve comprehension levels.However,apart from the familiarity,there is uncertainty about the ergonomic principles that could maximize the comprehension of traffic signs.Efforts should be made to ensure that different populations of road users sufficiently comprehend traffic signs。
