Actual sea condition testing and inspection and evaluation method research are carried out for tidal energy devices to provide scientific and effective technical support for the ocean high-tech achievement transformat...Actual sea condition testing and inspection and evaluation method research are carried out for tidal energy devices to provide scientific and effective technical support for the ocean high-tech achievement transformation and marine renewable energy development. By analyzing three core indicators, including the power output characteristics of the tidal current device, the generating capacity, energy conversion efficiency, proposed the test contents and evaluation methods of indicators are proposed in this paper; and based on the research of wind farms, power quality testing and assessment methods of offshore tidal energy device are proposed; given the security access to the test contents of tidal current energy device, tidal current energy device running conditions in the testing ground are comprehensively assessed.展开更多
Bridge engineering is an important part of basic engineering in today’s transportation field,and its quality and performance have a vital impact on the improvement and development of modern transportation engineering...Bridge engineering is an important part of basic engineering in today’s transportation field,and its quality and performance have a vital impact on the improvement and development of modern transportation engineering.With the continuous development of transportation engineering,the maintenance and reinforcement of existing bridges are also being given more emphasis.In order to scientifically evaluate the effectiveness of bridge maintenance and reinforcement,this paper analyzes its detection and evaluation,including the significance,key points,and main methods of detection and evaluation.Therefore,this analysis aim to provide some reference for the maintenance and reinforcement and the quality improvement of bridge engineering.展开更多
Objective: To examine the correlation between plasma hCG results obtained with the new i-STAT® hCG point of care test with those concomitantly obtained from the central hospital laboratory utilizing the same pa...Objective: To examine the correlation between plasma hCG results obtained with the new i-STAT® hCG point of care test with those concomitantly obtained from the central hospital laboratory utilizing the same patient samples. Methods: Prospective cross-sectional laboratory test evaluation. We compared plasma hCG results obtained with the i-STAT® hCG test (Abbott Point of Care, Princeton, NJ, USA) with Architect Ci8200 (Abbott Laboratories, Abbott Park, IL, USA). We also calculated the total coefficient of variation (CV) for the i-STAT® method. Results: The two methods showed a good linear correlation (R2 = 0.994;slope 1.03) and CV for the i-STAT® method was 2.1% - 5.2%. Conclusion: We suggest that the i-STAT® hCG blood assay could be used as a complement to urine hCG assays in clinical situations when rapid test results are needed and urine is not available.展开更多
The water quality in the Danjiangkou Reservoir has attracted considerable attention from the Chinese public and government since the announcement of the Middle Route of the South to North Water Diversion Project （SN...The water quality in the Danjiangkou Reservoir has attracted considerable attention from the Chinese public and government since the announcement of the Middle Route of the South to North Water Diversion Project （SNWDP）, which commenced transferring water in 2014. Integrated research on the evaluation, prediction, and protection of water quality in the Danjiangkou Reservoir was carried out in this study in order to improve environmental management. Based on 120 water samples, wherein 17 water quality indices were measured at 20 monitoring sites, a single factor evaluation method was used to evaluate the current status of water quality. The results show that the main indices influencing the water quality in the Danjiangkou Reservoir are total phosphorus （TP）, permanganate index （CODM,）, dissolved oxygen （DO）, and five-day biochemical oxygen demand （BODs）, and the concentrations of TP, BODs, ammonia nitrogen （NH3--N）, CODM,, DO, and anionic surfactant （Surfa） do not reach the specified standard levels in the tributaries. Seasonal Mann--Kendall tests indicated that the CODMn concentration shows a highly significant increasing trend, and the TP concentration shows a significant increasing trend in the Danjiangkou Reservoir. The distribution of the main water quality indices in the Danjiangkou Reservoir was predicted using a two-dimensional water quality numerical model, and showed that the sphere of influence from the tributaries can spread across half of the Han Reservoir if the pollutants are not controlled. Cluster analysis （CA） results suggest that the Shending River is heavily polluted, that the Jianghe, Sihe, and Jianhe rivers are moderately polluted, and that they should be the focus of environmental remediation.展开更多
The deformation characteristic of bland in deep drawing is discussed. It is pointed out that the friction and lubrication conditions in for drawing are different from that in mechanical motion or machine work or other...The deformation characteristic of bland in deep drawing is discussed. It is pointed out that the friction and lubrication conditions in for drawing are different from that in mechanical motion or machine work or other plastic process. The common test methods in laboratories are analyzed. It shows that though all those test methods can test the friction coefficient, the probe test method is most suitable for the research of friction and lubrication and the process in deep drawing, for this method is identical with the actual work condition either from the test principle or deformation status of the blank. Last the successful application in the deep drawing simulator newly developed the the probe method are intro- duced in detail.展开更多
A high-precision evaluation of ultrasonic detection sensitivity for a micro-crack can be restricted by a corroded rough surface when the surface microtopography is of the same order of magnitude as the crack depth.In ...A high-precision evaluation of ultrasonic detection sensitivity for a micro-crack can be restricted by a corroded rough surface when the surface microtopography is of the same order of magnitude as the crack depth.In this study,a back-surface micro-crack is considered as a research target.A roughness-modified ultrasonic testing model for micro-cracks is established based on a multi-Gaussian beam model and the principle of phase-screen approximation.The echo signals of micro-cracks and noises corresponding to different rough front surfaces and rough back surfaces are obtained based on a reference reflector signal acquired from a two-dimensional simulation model.Further compari-son between the analytical and numerical models shows that the responses of micro-cracks under the effects of dif-ferent corroded rough surfaces can be accurately predicted.The numerical and analytical results show that the echo signal amplitude of the micro-crack decreases significantly with an increase in roughness,whereas the noise ampli-tude slightly increases.Moreover,the effect of the rough front surface on the echo signal of the micro-crack is greater than that of the rough back surface.When the root-mean-square(RMS)height of the surface microtopography is less than 15μm,the two rough surfaces have less influence on the echo signals detected by a focused transducer with a frequency of 5 MHz and diameter of 6 mm.A method for predicting and evaluating the detection accuracy of micro-cracks under different rough surfaces is proposed by combining the theoretical model and a finite element simulation.Then,a series of rough surface samples containing different micro-cracks are fabricated to experimentally validate the evaluation method.展开更多
Key methods developed and used in the USSR and in the Russian Federation to determine the impact and friction sensitivity of energetic materials and explosives have been discussed.Experimental methodologies and instru...Key methods developed and used in the USSR and in the Russian Federation to determine the impact and friction sensitivity of energetic materials and explosives have been discussed.Experimental methodologies and instruments that underlie the assessment of their production and handling safety have been described.Studies of a large number of compounds have revealed relationships between their sensitivity parameters and structure of individual compounds and compositions.The range of change of physical and chemical characteristics for the compounds we examined covers the entire region of their existence.Theoretical methodology and equations have been formulated to estimate the impact and friction sensitivity parameters of energetic materials and to evaluate the technological safety in use.The developed methodology is characterized by high-accuracy calculations and prediction of sensitivity parameters.展开更多
Concrete-plate fences have been widely adopted for windblown sand control and mitigation along railways.However,the inclination angles of inserting the concrete plate with respect to the vertical direction,i.e.,straig...Concrete-plate fences have been widely adopted for windblown sand control and mitigation along railways.However,the inclination angles of inserting the concrete plate with respect to the vertical direction,i.e.,straight or obliquely inserted concrete plates(SIP or OIP),significantly influence the efficiency of sand-control.This study performs a comparative evaluation of the SIP and OIP sand-control fences using wind tunnel testing and field monitoring data collected from the Lanzhou–Wulumuqi High-Speed Railway Project.The results show that the fence’s ability to reduce the wind speed and the sand-retaining efficiency gradually weakens with the increasing wind speed.Compared with the SIP fence,the OIP fence has a better wind speed reduction capability,stronger ability to capture fine particles below the top of the fence;it is more efficient for sand-retaining and induces stronger eddy intensity.Generally,the wind tunnel test and field monitoring results are consistent,whereas wind tunnel tests incline to overestimate wind speed reduction and sand-control efficiency.The study also finds that the aeolian sand accumulated around the fence can weaken the protection efficiency,and hence cleaning the aeolian sand accumulated around the fence should be done periodically to ensure the designed functions.展开更多
Based on 31 fabric property parameters tested by FAST test system and other test instruments, the principal factors of fabric style are obtained through the principal factor analysis method and computer program. Accor...Based on 31 fabric property parameters tested by FAST test system and other test instruments, the principal factors of fabric style are obtained through the principal factor analysis method and computer program. According to the correlation between each parameter and principal factor, the selected positive or negative coefficient, the objective evaluation model of fabric style has been established based on the percentage of variance. And wool fabrics have been taken for example to show how to use the objective evaluation model for fabric design.展开更多
Participation in inter-comparison programs is an important process to enhance the accuracy and precision of the analytical techniques used in the laboratories. At Es-Salam Research Reactor, our laboratory uses two fun...Participation in inter-comparison programs is an important process to enhance the accuracy and precision of the analytical techniques used in the laboratories. At Es-Salam Research Reactor, our laboratory uses two functional analytical techniques such as INAA and k0-INAA in the research projects and for the completion of the service works. Recently, our laboratory has participated in two inter-comparison tests organized by IAEA within the framework of the AFRA project to assess the analytical performance of eighteen (18) African analytical laboratories participating in the RAF/4/ 022 project, Enhancement of Research Reactor Utilization and Safety by taking part in analytical proficiency testing IAEA in conjunction with WEPAL, the Wageningen Evaluating Programs for Analytical Laboratories. The Proficiency Testing tests related to the determination of major, minor and trace elements in materials of the International Soil and Plant Analytical Exchange (Wepal codes ISE, IPE), were held in the fourth quarter of 2011 and the first quarter of 2012, respectively. Concentrations of thirty (30) elements such as Al, As, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Fe, Ga, K, La, Mg, Mo, Mn, Na, Nd, Rb, Sb, Sc, Sr, Th, Ti, U, V, W, Zn, Zr were determined in ISE and IPE samples. All results were evaluated and reported in this paper.展开更多
With the continuous development of science and technology and other fields in today's world,statistical analysis and research have become indispensable research methods in people's daily lives.Among these,hypo...With the continuous development of science and technology and other fields in today's world,statistical analysis and research have become indispensable research methods in people's daily lives.Among these,hypothesis testing plays an important role in fields such as biology,medicine,and economics,and has significant effects in most scenarios.However,the suitability and effectiveness of different hypothesis testing methods vary depending on the context,often leading to different outcomes and levels of accuracy.This paper focuses on discussing various hypothesis testing methods in statistics,such as t-test,chi-square test,z-test,F-test,etc.In addition,this study analyzes various cases in real life and optimize and improve some hypothesis testing methods.Based on a review of existing literature,the study explores how traditional hypothesis testing determines statistical significance—where the null hypothesis is rejected if the test statistic falls within the rejection region.To improve and enhance the determination of the significance level,handle uncertainty,and increase the sample size,this paper proposes alternative methods such as NHST test,Bayesian test,big data sequential test,and failure rate hypothesis test from the perspectives of medicine and kinesiology.展开更多
The interaction between axially adjacent defects is more significant than that between circumferentially aligned defects.However,the existing failure pressure assessment methods cannot accurately predict the failure p...The interaction between axially adjacent defects is more significant than that between circumferentially aligned defects.However,the existing failure pressure assessment methods cannot accurately predict the failure pressure of axial adjacent defects.In the paper,the finite element model is adopted to analyze the influence of defect size,distribution mode and spacing between adjacent defects on failure pressure.A new failure pressure evaluation method is proposed by establishing the effective depth calculation model of corrosion colony with different distribution model.The burst test of X52 pipeline is carried out to verify the applicability of the method.It shows that the results of new method are consistent with the test results of pipeline with various defects and steel grades.展开更多
The chloride ion contained in reinforced concrete seriously corrodes the steel surface and damages concrete, resulting in inferior reinforced concrete that strength seriously compromises the entire structure’s safety...The chloride ion contained in reinforced concrete seriously corrodes the steel surface and damages concrete, resulting in inferior reinforced concrete that strength seriously compromises the entire structure’s safety. Consequently, the examination of chloride ions contained in reinforced concrete becomes an important part of a complete quality control procedure. To effectively check the concentration of chloride ions in concrete, the evaluation process should be accurate and precise. Laboratory data ob- tained using existing evaluation methods for the examination of chloride ion are not sufficiently objective to yield reliable results with accuracy and consistency for each sample. An evaluation algorithm with capability to define indices of precision degree (Ep) and accuracy degree (Ea) is presented in this paper. The authors established a statistically reliable index of unbiased estimators and equations to critically examine the laboratory methods’ precision, accuracy degrees and application value for measuring chlorine ion concentration in reinforced concrete.展开更多
Non-destructive measurement of absolute stress in steel members can provide useful information to optimize the design of steel structures and allow the safety of existing structures to be evaluated.This paper investig...Non-destructive measurement of absolute stress in steel members can provide useful information to optimize the design of steel structures and allow the safety of existing structures to be evaluated.This paper investigates the non-destructive capability of ultrasonic shear-wave spectroscopy in absolute stress evaluation of steel members.The effect of steel-member stress on the shear-wave amplitude spectrum is investigated,and a method of absolute stress measurement is proposed.Specifically,the process for evaluating absolute stress using shear-wave spectroscopy is summarized.Two steel members are employed to investigate the relationship between the stress and the frequency in shear-wave echo amplitude spectrum.The H-beam loaded by the universal testing machine is evaluated by the proposed method and the traditional strain gauge method for verification.The results show that the proposed method is effective and accurate for determining absolute stress in steel members.展开更多
基金supported by the Implementation Programs for Marine Renewable Energy Special Funds (GHME2012ZC02)
文摘Actual sea condition testing and inspection and evaluation method research are carried out for tidal energy devices to provide scientific and effective technical support for the ocean high-tech achievement transformation and marine renewable energy development. By analyzing three core indicators, including the power output characteristics of the tidal current device, the generating capacity, energy conversion efficiency, proposed the test contents and evaluation methods of indicators are proposed in this paper; and based on the research of wind farms, power quality testing and assessment methods of offshore tidal energy device are proposed; given the security access to the test contents of tidal current energy device, tidal current energy device running conditions in the testing ground are comprehensively assessed.
文摘Bridge engineering is an important part of basic engineering in today’s transportation field,and its quality and performance have a vital impact on the improvement and development of modern transportation engineering.With the continuous development of transportation engineering,the maintenance and reinforcement of existing bridges are also being given more emphasis.In order to scientifically evaluate the effectiveness of bridge maintenance and reinforcement,this paper analyzes its detection and evaluation,including the significance,key points,and main methods of detection and evaluation.Therefore,this analysis aim to provide some reference for the maintenance and reinforcement and the quality improvement of bridge engineering.
文摘Objective: To examine the correlation between plasma hCG results obtained with the new i-STAT® hCG point of care test with those concomitantly obtained from the central hospital laboratory utilizing the same patient samples. Methods: Prospective cross-sectional laboratory test evaluation. We compared plasma hCG results obtained with the i-STAT® hCG test (Abbott Point of Care, Princeton, NJ, USA) with Architect Ci8200 (Abbott Laboratories, Abbott Park, IL, USA). We also calculated the total coefficient of variation (CV) for the i-STAT® method. Results: The two methods showed a good linear correlation (R2 = 0.994;slope 1.03) and CV for the i-STAT® method was 2.1% - 5.2%. Conclusion: We suggest that the i-STAT® hCG blood assay could be used as a complement to urine hCG assays in clinical situations when rapid test results are needed and urine is not available.
基金supported by the National Natural Science Foundation of China(Grants No.41101250 and 51309031)the Chinese 12th Five-Year Science and Technology Support Program(Grant No.2012BAC06B00)
文摘The water quality in the Danjiangkou Reservoir has attracted considerable attention from the Chinese public and government since the announcement of the Middle Route of the South to North Water Diversion Project （SNWDP）, which commenced transferring water in 2014. Integrated research on the evaluation, prediction, and protection of water quality in the Danjiangkou Reservoir was carried out in this study in order to improve environmental management. Based on 120 water samples, wherein 17 water quality indices were measured at 20 monitoring sites, a single factor evaluation method was used to evaluate the current status of water quality. The results show that the main indices influencing the water quality in the Danjiangkou Reservoir are total phosphorus （TP）, permanganate index （CODM,）, dissolved oxygen （DO）, and five-day biochemical oxygen demand （BODs）, and the concentrations of TP, BODs, ammonia nitrogen （NH3--N）, CODM,, DO, and anionic surfactant （Surfa） do not reach the specified standard levels in the tributaries. Seasonal Mann--Kendall tests indicated that the CODMn concentration shows a highly significant increasing trend, and the TP concentration shows a significant increasing trend in the Danjiangkou Reservoir. The distribution of the main water quality indices in the Danjiangkou Reservoir was predicted using a two-dimensional water quality numerical model, and showed that the sphere of influence from the tributaries can spread across half of the Han Reservoir if the pollutants are not controlled. Cluster analysis （CA） results suggest that the Shending River is heavily polluted, that the Jianghe, Sihe, and Jianhe rivers are moderately polluted, and that they should be the focus of environmental remediation.
文摘The deformation characteristic of bland in deep drawing is discussed. It is pointed out that the friction and lubrication conditions in for drawing are different from that in mechanical motion or machine work or other plastic process. The common test methods in laboratories are analyzed. It shows that though all those test methods can test the friction coefficient, the probe test method is most suitable for the research of friction and lubrication and the process in deep drawing, for this method is identical with the actual work condition either from the test principle or deformation status of the blank. Last the successful application in the deep drawing simulator newly developed the the probe method are intro- duced in detail.
基金Supported by the Key Research and Development Plan of Anhui Province(Grant No.202004a05020003)Anhui Provincial Natural Science Foundation(Grant Nos.2008085QE233,2008085J24)+1 种基金the Science and Technology Major Project of Anhui Province(Grant No.201903a05020010)the Doctoral Science and Technology Foundation of Hefei General Machinery Research Institute(Grant No.2019010383).
文摘A high-precision evaluation of ultrasonic detection sensitivity for a micro-crack can be restricted by a corroded rough surface when the surface microtopography is of the same order of magnitude as the crack depth.In this study,a back-surface micro-crack is considered as a research target.A roughness-modified ultrasonic testing model for micro-cracks is established based on a multi-Gaussian beam model and the principle of phase-screen approximation.The echo signals of micro-cracks and noises corresponding to different rough front surfaces and rough back surfaces are obtained based on a reference reflector signal acquired from a two-dimensional simulation model.Further compari-son between the analytical and numerical models shows that the responses of micro-cracks under the effects of dif-ferent corroded rough surfaces can be accurately predicted.The numerical and analytical results show that the echo signal amplitude of the micro-crack decreases significantly with an increase in roughness,whereas the noise ampli-tude slightly increases.Moreover,the effect of the rough front surface on the echo signal of the micro-crack is greater than that of the rough back surface.When the root-mean-square(RMS)height of the surface microtopography is less than 15μm,the two rough surfaces have less influence on the echo signals detected by a focused transducer with a frequency of 5 MHz and diameter of 6 mm.A method for predicting and evaluating the detection accuracy of micro-cracks under different rough surfaces is proposed by combining the theoretical model and a finite element simulation.Then,a series of rough surface samples containing different micro-cracks are fabricated to experimentally validate the evaluation method.
文摘Key methods developed and used in the USSR and in the Russian Federation to determine the impact and friction sensitivity of energetic materials and explosives have been discussed.Experimental methodologies and instruments that underlie the assessment of their production and handling safety have been described.Studies of a large number of compounds have revealed relationships between their sensitivity parameters and structure of individual compounds and compositions.The range of change of physical and chemical characteristics for the compounds we examined covers the entire region of their existence.Theoretical methodology and equations have been formulated to estimate the impact and friction sensitivity parameters of energetic materials and to evaluate the technological safety in use.The developed methodology is characterized by high-accuracy calculations and prediction of sensitivity parameters.
基金supported by the Science and Technology Development Plan of China Railway Group Limited(Grant No.2015-kj035-g004-03).
文摘Concrete-plate fences have been widely adopted for windblown sand control and mitigation along railways.However,the inclination angles of inserting the concrete plate with respect to the vertical direction,i.e.,straight or obliquely inserted concrete plates(SIP or OIP),significantly influence the efficiency of sand-control.This study performs a comparative evaluation of the SIP and OIP sand-control fences using wind tunnel testing and field monitoring data collected from the Lanzhou–Wulumuqi High-Speed Railway Project.The results show that the fence’s ability to reduce the wind speed and the sand-retaining efficiency gradually weakens with the increasing wind speed.Compared with the SIP fence,the OIP fence has a better wind speed reduction capability,stronger ability to capture fine particles below the top of the fence;it is more efficient for sand-retaining and induces stronger eddy intensity.Generally,the wind tunnel test and field monitoring results are consistent,whereas wind tunnel tests incline to overestimate wind speed reduction and sand-control efficiency.The study also finds that the aeolian sand accumulated around the fence can weaken the protection efficiency,and hence cleaning the aeolian sand accumulated around the fence should be done periodically to ensure the designed functions.
文摘Based on 31 fabric property parameters tested by FAST test system and other test instruments, the principal factors of fabric style are obtained through the principal factor analysis method and computer program. According to the correlation between each parameter and principal factor, the selected positive or negative coefficient, the objective evaluation model of fabric style has been established based on the percentage of variance. And wool fabrics have been taken for example to show how to use the objective evaluation model for fabric design.
文摘Participation in inter-comparison programs is an important process to enhance the accuracy and precision of the analytical techniques used in the laboratories. At Es-Salam Research Reactor, our laboratory uses two functional analytical techniques such as INAA and k0-INAA in the research projects and for the completion of the service works. Recently, our laboratory has participated in two inter-comparison tests organized by IAEA within the framework of the AFRA project to assess the analytical performance of eighteen (18) African analytical laboratories participating in the RAF/4/ 022 project, Enhancement of Research Reactor Utilization and Safety by taking part in analytical proficiency testing IAEA in conjunction with WEPAL, the Wageningen Evaluating Programs for Analytical Laboratories. The Proficiency Testing tests related to the determination of major, minor and trace elements in materials of the International Soil and Plant Analytical Exchange (Wepal codes ISE, IPE), were held in the fourth quarter of 2011 and the first quarter of 2012, respectively. Concentrations of thirty (30) elements such as Al, As, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Fe, Ga, K, La, Mg, Mo, Mn, Na, Nd, Rb, Sb, Sc, Sr, Th, Ti, U, V, W, Zn, Zr were determined in ISE and IPE samples. All results were evaluated and reported in this paper.
文摘With the continuous development of science and technology and other fields in today's world,statistical analysis and research have become indispensable research methods in people's daily lives.Among these,hypothesis testing plays an important role in fields such as biology,medicine,and economics,and has significant effects in most scenarios.However,the suitability and effectiveness of different hypothesis testing methods vary depending on the context,often leading to different outcomes and levels of accuracy.This paper focuses on discussing various hypothesis testing methods in statistics,such as t-test,chi-square test,z-test,F-test,etc.In addition,this study analyzes various cases in real life and optimize and improve some hypothesis testing methods.Based on a review of existing literature,the study explores how traditional hypothesis testing determines statistical significance—where the null hypothesis is rejected if the test statistic falls within the rejection region.To improve and enhance the determination of the significance level,handle uncertainty,and increase the sample size,this paper proposes alternative methods such as NHST test,Bayesian test,big data sequential test,and failure rate hypothesis test from the perspectives of medicine and kinesiology.
基金supported by the Key Scientific Research Projects of Colleges and Universities in Henan Province(Grant No.23A560013)the National Key R&D Program of the“14th Five-Year Plan”(Grant No.2022YFC3801001)+1 种基金Henan Provincial Youth Science Foundation(Grant No.232300421328)the Leading Talents in Zhongyuan Technology Innovation(Grant No.234200510014).
文摘The interaction between axially adjacent defects is more significant than that between circumferentially aligned defects.However,the existing failure pressure assessment methods cannot accurately predict the failure pressure of axial adjacent defects.In the paper,the finite element model is adopted to analyze the influence of defect size,distribution mode and spacing between adjacent defects on failure pressure.A new failure pressure evaluation method is proposed by establishing the effective depth calculation model of corrosion colony with different distribution model.The burst test of X52 pipeline is carried out to verify the applicability of the method.It shows that the results of new method are consistent with the test results of pipeline with various defects and steel grades.
基金Project (No. NSC-93-2211-E-167-002) supported by the NationalScience Council of Taiwan China
文摘The chloride ion contained in reinforced concrete seriously corrodes the steel surface and damages concrete, resulting in inferior reinforced concrete that strength seriously compromises the entire structure’s safety. Consequently, the examination of chloride ions contained in reinforced concrete becomes an important part of a complete quality control procedure. To effectively check the concentration of chloride ions in concrete, the evaluation process should be accurate and precise. Laboratory data ob- tained using existing evaluation methods for the examination of chloride ion are not sufficiently objective to yield reliable results with accuracy and consistency for each sample. An evaluation algorithm with capability to define indices of precision degree (Ep) and accuracy degree (Ea) is presented in this paper. The authors established a statistically reliable index of unbiased estimators and equations to critically examine the laboratory methods’ precision, accuracy degrees and application value for measuring chlorine ion concentration in reinforced concrete.
基金supported by the National Key Research and Development Program of China (No. 2016YFC0701102)the National Nature Science Foundation of China(No.51538003)the Shenzhen Technology Innovation Program (No.JSGG20150330103937411)
文摘Non-destructive measurement of absolute stress in steel members can provide useful information to optimize the design of steel structures and allow the safety of existing structures to be evaluated.This paper investigates the non-destructive capability of ultrasonic shear-wave spectroscopy in absolute stress evaluation of steel members.The effect of steel-member stress on the shear-wave amplitude spectrum is investigated,and a method of absolute stress measurement is proposed.Specifically,the process for evaluating absolute stress using shear-wave spectroscopy is summarized.Two steel members are employed to investigate the relationship between the stress and the frequency in shear-wave echo amplitude spectrum.The H-beam loaded by the universal testing machine is evaluated by the proposed method and the traditional strain gauge method for verification.The results show that the proposed method is effective and accurate for determining absolute stress in steel members.
