Although machine Learning has demonstrated exceptional applicability in thermographic inspection,precise defect reconstruction is still challenging,especially for complex defect profiles with limited defect sample div...Although machine Learning has demonstrated exceptional applicability in thermographic inspection,precise defect reconstruction is still challenging,especially for complex defect profiles with limited defect sample diversity.Thus,this paper proposes a self-enhancement defect reconstruction technique based on cycle-consistent generative adversarial network(Cycle-GAN)that accurately characterises complex defect profiles and generates reliable artificial thermal images for dataset augmentation,enhancing defect characterisation.By using a synthetic dataset from simulation and experiments,the network overcomes the limited samples problem by learning the diversity of complex defects from finite element modelling and obtaining the thermography uncertainty patterns from practical experiments.Then,an iterative strategy with a self-enhancement capability optimises the characterisation accuracy and data generation performance.The designed loss function structure with cycle consistency and identity loss constrains the GAN’s transfer variation to guarantee augmented data quality and defect reconstruction accuracy simultaneously,while the self-enhancement results significantly improve accuracy in thermal images and defect profile reconstruction.The experimental results demonstrate the feasibility of the proposed method by attaining high accuracy with optimal loss norm for defect profile reconstruction with a Recall score over 0.92.The scalability investigation of different materials and defect types is also discussed,highlighting its capability for diverse thermography quantification and automated inspection scenarios.展开更多
Understanding rock behavior is crucial in mine geotechnical engineering to ensure construction efficiency,mitigate rock-related hazards,and promote environmental sustainability.Coda Wave Interferometry(CWI),a non-dest...Understanding rock behavior is crucial in mine geotechnical engineering to ensure construction efficiency,mitigate rock-related hazards,and promote environmental sustainability.Coda Wave Interferometry(CWI),a non-destructive ultrasonic testing method,has been widely employed to assess micro-damage evolution in rocks induced by perturbations in scatterer position,velocity,or source location due to its exceptional sensitivity.However,challenges persist in evaluating cross-scale rock behavior influenced by nonlinear deformation and multi-field interactions under multiple coupled perturbations.A comprehensive review of the perturbation factors affecting rock damage evolution and potential failure mechanisms is essential for presenting available knowledge in a more systematic and structured manner.This review provides an in-depth analysis of the CWI technique,encompassing its origins,theoretical framework,and classical data processing methodologies.Additionally,it explores the diverse applications of CWI in assessing rock behavior under various perturbation factors,including temperature variations,fluid infiltration,and stress conditions,with a particular emphasis on nonlinear deformation and multi-field coupling effects.Furthermore,a novel method for calculating relative velocity changes in coda waves is introduced,enabling a more precise characterization of the entire rock failure process.The study also proposes a cutting-edge concept of ultra-early and refined monitoring and warning technology for mine rock disasters,leveraging the advancements in CWI.Finally,the review highlights the potential future developments of CWI in high-level intelligent mining scenarios,particularly its integration with ambient noise interferometry and microseismic coda wave analysis.This work serves as a valuable reference,contributing to the refinement of CWI applications for assessing complex rock behavior and enhancing the accuracy of rock disaster prediction and early warning systems.展开更多
BACKGROUND Previous studies have validated the efficacy of both magnetic compression and surgical techniques in creating rabbit tracheoesophageal fistula(TEF)models.Magnetic compression achieves a 100%success rate but...BACKGROUND Previous studies have validated the efficacy of both magnetic compression and surgical techniques in creating rabbit tracheoesophageal fistula(TEF)models.Magnetic compression achieves a 100%success rate but requires more time,while surgery,though less frequently successful,offers rapid model establishment and technical maturity in larger animal models.AIM To determine the optimal approach for rabbit disease modeling and refine the process.METHODS TEF models were created in 12 rabbits using both the modified magnetic compression technique and surgery.Comparisons of the time to model establishment,success rate,food and water intake,weight changes,activity levels,bronchoscopy findings,white blood cell counts,and biopsies were performed.In response to the failures encountered during modified magnetic compression modeling,we increased the sample size to 15 rabbit models and assessed the repeatability and stability of the models,comparing them with the original magnetic compression technique.RESULTS The modified magnetic compression technique achieved a 66.7%success rate,whereas the success rate of the surgery technique was 33.3%.Surviving surgical rabbits might not meet subsequent experimental requirements due to TEF-related inflammation.In the modified magnetic compression group,one rabbit died,possibly due to magnet corrosion,and another died from tracheal magnet obstruction.Similar events occurred during the second round of modified magnetic compression modeling,with one rabbit possibly succumbing to aggravated lung infection.The operation time of the first round of modified magnetic compression was 3.2±0.6 min,which was significantly reduced to 2.1±0.4 min in the second round,compared to both the first round and that of the original technique.CONCLUSION The modified magnetic compression technique exhibits lower stress responses,a simple procedure,a high success rate,and lower modeling costs,making it a more appropriate choice for constructing TEF models in rabbits.展开更多
Pulsed eddy current （PEC） non-destructive test- ing and evaluation （NDT＆E） has been around for some time and it is still attracting extensive attention from researchers around the globe, which can be witnessed th...Pulsed eddy current （PEC） non-destructive test- ing and evaluation （NDT＆E） has been around for some time and it is still attracting extensive attention from researchers around the globe, which can be witnessed through the reports reviewed in this paper. Thanks to its richness of spectral components, various applications of this technique have been proposed and reported in the lit- erature covering both structural integrity inspection and material characterization in various industrial sectors. To support its development and for better understanding of the phenomena around the transient induced eddy currents, attempts for its modelling both analytically and numeri- cally have been made by researchers around the world. This review is an attempt to capture the state-of-the-art development and applications of PEC, especially in the last 15 years and it is not intended to be exhaustive. Future challenges and opportunities for PEC NDT＆E are also presented.展开更多
The karst mountainous area is an ecologically fragile region with prominent humanland contradictions.The resource-environment carrying capacity(RECC)of this region needs to be further clarified.The development of remo...The karst mountainous area is an ecologically fragile region with prominent humanland contradictions.The resource-environment carrying capacity(RECC)of this region needs to be further clarified.The development of remote sensing(RS)and geographic information system(GIS)provides data sources and processing platform for RECC monitoring.This study analyzed and established the evaluation index system of RECC by considering particularity in the karst mountainous area of Southwest China;processed multisource RS data(Sentinel-2,Aster-DEM and Landsat-8)to extract the spatial distributions of nine key indexes by GIS techniques(information classification,overlay analysis and raster calculation);proposed the methods of index integration and fuzzy comprehensive evaluation of the RECC by GIS;and took a typical area,Guangnan County in Yunnan Province of China,as an experimental area to explore the effectiveness of the indexes and methods.The results showed that:(1)The important indexes affecting the RECC of karst mountainous area are water resources,tourism resources,position resources,geographical environment and soil erosion environment.(2)Data on cultivated land,construction land,minerals,transportation,water conservancy,ecosystem services,topography,soil erosion and rocky desertification can be obtained from RS data.GIS techniques integrate the information into the RECC results.The data extraction and processing methods are feasible on evaluating RECC.(3)The RECC of Guangnan County was in the mid-carrying level in 2018.The midcarrying and low-carrying levels were the main types,accounting for more than 80.00%of the total study area.The areas with high carrying capacity were mainly distributed in the northern regions of the northwest-southeast line of the county,and other areas have a low carrying capacity comparatively.The coordination between regional resource-environment status and socioeconomic development is the key to improve RECC.This study explores the evaluation index system of RECC in karst mountainous area and the application of multisource RS data and GIS techniques in the comprehensive evaluation.The methods can be applied in related fields to provide suggestions for data/information extraction and integration,and sustainable development.展开更多
In recent years, advanced composite structures are used extensively in many industries such as aerospace, aircraft, automobile, pipeline and civil engineering. Reliability and safety are crucial requirements posed by ...In recent years, advanced composite structures are used extensively in many industries such as aerospace, aircraft, automobile, pipeline and civil engineering. Reliability and safety are crucial requirements posed by them to the advanced composite structures be- cause of their harsh working conditions. Therefore, as a very important measure, structural health monitoring （SHM） in-service is deft- nitely demanded for ensuring their safe working in-situ. In this paper, fiber Bragg grating （FBG） sensors are surface-mounted on the hoop and in the axial directions of a FRP pressure vessel to monitor the strain status during its pressurization. The experimental results show that the FBG sensors could be used to monitor the strain development and determine the ultimate failure strain of the composite pressure vessel.展开更多
In the world,nonalcoholic fatty liver disease(NAFLD)accounts for majority of diffuse hepatic diseases.Notably,substantial liver fat accumulation can trigger and accelerate hepatic fibrosis,thus contributing to disease...In the world,nonalcoholic fatty liver disease(NAFLD)accounts for majority of diffuse hepatic diseases.Notably,substantial liver fat accumulation can trigger and accelerate hepatic fibrosis,thus contributing to disease progression.Moreover,the presence of NAFLD not only puts adverse influences for liver but is also associated with an increased risk of type 2 diabetes and cardiovascular diseases.Therefore,early detection and quantified measurement of hepatic fat content are of great importance.Liver biopsy is currently the most accurate method for the evaluation of hepatic steatosis.However,liver biopsy has several limitations,namely,its invasiveness,sampling error,high cost and moderate intraobserver and interobserver reproducibility.Recently,various quantitative imaging techniques have been developed for the diagnosis and quantified measurement of hepatic fat content,including ultrasound-or magnetic resonancebased methods.These quantitative imaging techniques can provide objective continuous metrics associated with liver fat content and be recorded for comparison when patients receive check-ups to evaluate changes in liver fat content,which is useful for longitudinal follow-up.In this review,we introduce several imaging techniques and describe their diagnostic performance for the diagnosis and quantified measurement of hepatic fat content.展开更多
This paper introduces recent research work in the field of pulsed electromagnetic non-destructive testing/evaluation.These are pulsed eddy current,pulsed magnetic flux leakage and eddy current pulsed thermography.This...This paper introduces recent research work in the field of pulsed electromagnetic non-destructive testing/evaluation.These are pulsed eddy current,pulsed magnetic flux leakage and eddy current pulsed thermography.This paper introduces pulsed electromagnetic techniques and their different case studies on defect detection as well as stress characterisation.Experimental tests have been validated and future research plans are discussed.This paper demonstrates pulsed electromagnetic non-destructive testing and evaluation for not only depth information,but also for multiple parameter measurement and multiple integration,which are important for future development.展开更多
This article should not be considered as a full review of current methods for non-destructive testing of surface layers. Rather, it is a subjective in this area. However, the article provides some review of the challe...This article should not be considered as a full review of current methods for non-destructive testing of surface layers. Rather, it is a subjective in this area. However, the article provides some review of the challenges posed by the current state of surface layers treatment techniques on the area of Non-Destructive materials evaluation: enhancement of the sensitivity to the type of defects, increasing resolution to submicron values, the requirement to diagnose the surface layers with depth resolution of properties, diagnosis of multilayer multicomponent surface layers and coatings, treated with concentrated energy.展开更多
Purpose – This study aims to analyze the factors, evaluation techniques of the durability of existing railwayengineering.Design/methodology/approach – China has built a railway network of over 150,000 km. Ensuring t...Purpose – This study aims to analyze the factors, evaluation techniques of the durability of existing railwayengineering.Design/methodology/approach – China has built a railway network of over 150,000 km. Ensuring thesafety of the existing railway engineering is of great significance for maintaining normal railway operationorder. However, railway engineering is a strip structure that crosses multiple complex environments. Andrailway engineering will withstand high-frequency impact loads from trains. The above factors have led todifferences in the deterioration characteristics and maintenance strategies of railway engineering compared toconventional concrete structures. Therefore, it is very important to analyze the key factors that affect thedurability of railway structures and propose technologies for durability evaluation.Findings – The factors that affect the durability and reliability of railway engineering are mainly divided intothree categories: material factors, environmental factors and load factors. Among them, material factors alsoinclude influencing factors, such as raw materials, mix proportions and so on. Environmental factors varydepending on the service environment of railway engineering, and the durability and deterioration of concretehave different failure mechanisms. Load factors include static load and train dynamic load. The on-site rapiddetection methods for five common diseases in railway engineering are also proposed in this paper. Thesemethods can quickly evaluate the durability of existing railway engineering concrete.Originality/value – The research can provide some new evaluation techniques and methods for thedurability of existing railway engineering.展开更多
Nondestructive techniques for appraising gas metal arc welding（GMAW） faults plays a very important role in on-line quality controllability and prediction of the GMAW process. On-line welding quality controllability ...Nondestructive techniques for appraising gas metal arc welding（GMAW） faults plays a very important role in on-line quality controllability and prediction of the GMAW process. On-line welding quality controllability and prediction have several disadvantages such as high cost, low efficiency, complication and greatly being affected by the environment. An enhanced, efficient evaluation technique for evaluating welding faults based on Mahalanobis distance（MD） and normal distribution is presented. In addition, a new piece of equipment, designated the weld quality tester（WQT）, is developed based on the proposed evaluation technique. MD is superior to other multidimensional distances such as Euclidean distance because the covariance matrix used for calculating MD takes into account correlations in the data and scaling. The values of MD obtained from welding current and arc voltage are assumed to follow a normal distribution. The normal distribution has two parameters： the meanm and standard deviations of the data. In the proposed evaluation technique used by the WQT, values of MD located in the range from zero tom＋3s are regarded as “good”. Two experiments which involve changing the flow of shielding gas and smearing paint on the surface of the substrate are conducted in order to verify the sensitivity of the proposed evaluation technique and the feasibility of using WQT. The experimental results demonstrate the usefulness of the WQT for evaluating welding quality. The proposed technique can be applied to implement the on-line welding quality controllability and prediction, which is of great importance to design some novel equipment for weld quality detection.展开更多
The QBC techmique in diagnosing vivax malaria was compared with that of the Giemsa stained thick smear under field conditions in Sifang Village.Junlian County,Sichuan Province,China.Blood samples were collected from 1...The QBC techmique in diagnosing vivax malaria was compared with that of the Giemsa stained thick smear under field conditions in Sifang Village.Junlian County,Sichuan Province,China.Blood samples were collected from 161 volunteer villagers.Each sample was examined with both the QBC and Giemsa techniques.Each stained Giemsa thick smear(GTS)was prepared by spreading 10ul blood over an appropriate area on a slide and examined for 300 oil immersion fields,and each QBC tube was observed for 5 min.before considering a sample to be negative.Results showed that 34 blood samples were positive for vivax malaria and 127 were negative by GTS,whereas,there were 32 positives and 129 negatives by QBC.Taking GTS as standard,the sensjtivityand specificity of the QBC technique were 79.41%and 96.06%respectively,and the concordancewas 92.55%.Distributions of different developmental stages of P.raraz parasites in the centrifuged QBC tubes were cbserved and recorded,and the results revealed that all stages except schizonts,could be found in the lower part of the platelet zone,or the interphase between the monocyte and theplatelet layers,especially the ring forms.展开更多
Whole-life-cycle integrity management of underground gas storages(UGSs)has been an important link to ensure its long-term safe and efficient operation.At present,the integrity of UGSs in oil/gasfields and its evaluati...Whole-life-cycle integrity management of underground gas storages(UGSs)has been an important link to ensure its long-term safe and efficient operation.At present,the integrity of UGSs in oil/gasfields and its evaluation techniques focus on surface facilities and injection/withdrawal wells,but its geological integrity lacks clear definition and evaluation object and systematic evaluation techniques.In this paper,relevant research achievements werefirstly summarized.Then,the concept of geological integrity with the gas-storage geological body as the evaluation object was put forward,and the evaluation system for the geological integrity of such UGSs was established.Finally,UGS geological integrity evaluation was carried out with the Hutubi Underground Gas Storage in Xinjiang as an example.And the following research results were obtained.First,UGS geological integrity is defined as the integrity degree of each component of a gas-storage geological body to meet operation requirements and fulfill seasonal and emergency peak shaving safely and economically during the operation of a UGS.Its connotation is that reservoir of geological body,caprock,fault and trap can supply the customers with gas continuously and stably and ensure the safe operation of the UGS in its service life.And its core lies in keeping the reliability,safety and economy of natural gas storage in the service life of a UGS.Second,the geological integrity evaluation system is composed of four evaluation techniques,including trap effectiveness,caprock integrity,fault stability and reservoir stability.Third,the evaluation results show that the Hutubi Underground Gas Storage has the potential of peak-shaving capacity enhancement by increasing the maximum operation pressure.In conclusion,the establishment of the geological integrity evaluation system for such UGSs improves the UGS integrity evaluation technique system and plays an instructive and practical role in ensuring the long-term safe and efficient operation of UGSs,increasing the maximum operation pressure and improving the peak shaving capacity.展开更多
A non invasive ultrasonic method is used to detect whether or not the frozen fish has suffered a partial or total accidental thawing. The time of flight and the peak to peak amplitude of the ultrasonic signals backsca...A non invasive ultrasonic method is used to detect whether or not the frozen fish has suffered a partial or total accidental thawing. The time of flight and the peak to peak amplitude of the ultrasonic signals backscattered by fish are recorded during thawing. The comparison of the evolution curves and images corresponding to first and second thawing shows indicators of accidental thawing. The monitoring of thawing process showed that its assessment can be reduced to the measurement of the water content lost by fish. The attempt to replace the original water lost by fish in first thawing is analyzed. The influence of the transducer frequency on fish thawing evaluation is tested.展开更多
Introduction The use of supercritical fluids such as supercritical CO<sub>2</sub>（scCO<sub>2</sub>） has provided a ’clean’ and effective alternative to traditional methods of protein delive...Introduction The use of supercritical fluids such as supercritical CO<sub>2</sub>（scCO<sub>2</sub>） has provided a ’clean’ and effective alternative to traditional methods of protein delivery systems.Here。展开更多
How＇s the effect of technical import actually？ The latter stage evaluation to technique import project is necessary to get the answer. Therefore, the latter stage evaluation to technique import project is not equal ...How＇s the effect of technical import actually？ The latter stage evaluation to technique import project is necessary to get the answer. Therefore, the latter stage evaluation to technique import project is not equal to the latter stage evaluation to general construction projects, it doesn＇t emphasize particularly on its economic profits but the performance of the digest, generalization, improvement and redevelopment of the imported technique.展开更多
Composite materials are increasingly used in the aerospace and automotive industries due to their high strength-toweight ratio and fatigue resistance.These structures may develop internal defects during manufacturing ...Composite materials are increasingly used in the aerospace and automotive industries due to their high strength-toweight ratio and fatigue resistance.These structures may develop internal defects during manufacturing or service,compromising their integrity and safety.Thus,non-destructive defect detection is critical during production to ensure safety and reliability.This study explores the application of terahertz time-domain spectroscopy(THz-TDS)for detecting damage in different glass fiber-reinforced polymer(GFRP)manufacturing processes.A cross-correlation-based impulse response function extraction algorithm and image enhancement method are proposed.The method targets both deep and minor defects in GFRP,leveraging the correlation between the terahertz reference signal and the time-domain detection signal to extract the terahertz impulse response function via a one-dimensional iterative deconvolution algorithm.Testing on samples with pre-fabricated delamination,three-point bending damage,and drilled damage demonstrated the method’s efficacy in extracting impulse response functions of delamination defects,which aids in defect localization and improved image representation.In the THz imaging analysis of GFRP manufacturing process damage,signal alignment,windowing,and morphology positioning techniques were applied based on the extracted impulse response functions.The proposed method significantly improved the quality of THz images for defect detection in GFRP,as demonstrated by objective evaluations and comparisons.These advancements provide a robust and effective tool for the non-destructive evaluation of composite materials.展开更多
To explore the value of helical CT volume rendering technique (VRT) in post-operative evaluation of screw fixation of axis fractures.Methods There were 21 cases of screw fixation of axis fractures between February 200...To explore the value of helical CT volume rendering technique (VRT) in post-operative evaluation of screw fixation of axis fractures.Methods There were 21 cases of screw fixation of axis fractures between February 2002 and May 2004 in the study including six cases with fractures on axis body,five on odontoid process and 10 on axis body and odontoid process.All cases received X-ray plain film,helical CT scanning,multi-planar reformatting(MPR) and VRT.Results Screw fixation through axis body and massa lateralis atlantis was performed in 10 cases and that through axis body and odontoid process in 11.VRT could clearly display full aperture of screw orbit,location of screw and angle of fixation and hence was superior to X-ray plain film and MPR.Multi-angle VRT displayed asymmetrical space of odontoid process and massa lateralis atlantis in four cases and medial deviation of 2～5 mm of half screw in screw fixation through axis body and massa lateralis atlantis in six.Conclusion VRT can eliminate false shadow of fixation screw,clearly display full aperture of screw orbit and hence supply improtant imaging evidence for post-operative evaluation of screw fixation of axis fractures.7 refs,1 fig,1 tab.展开更多
The use of non-destructive evaluation(NDE) techniques for assessing microstructural changes in processed materials is of particular importance as it can be used to assess, qualitatively, the integrity of any material/...The use of non-destructive evaluation(NDE) techniques for assessing microstructural changes in processed materials is of particular importance as it can be used to assess, qualitatively, the integrity of any material/structure. Among the several NDE techniques available, electrical conductivity measurements using eddy currents attract great attention owing to its simplicity and reliability. In this work, the electrical conductivity profiles of friction stir processed Ti6Al4 V, Cu, Pb, S355 steel and gas tungsten arc welded AISI 304 stainless steel were determined through eddy currents and four-point probe. In parallel, hardness measurements were also performed. The profiles matched well with the optical macrographs of the materials: while entering in the processed region a variation in both profiles was always observed. One particular advantage of electrical conductivity profiles over hardness was evident: it provides a better resolution of the microstructural alterations in the processed materials. Moreover, when thermomechanical processing induces microstructural changes that modify the magnetic properties of a material,eddy currents testing can be used to qualitatively determine the phase fraction in a given region of the material. A qualitative relation between electrical conductivity measurements and hardness is observed.展开更多
基金supported by the UK EPSRC Platform Grant:Through-life performance:From science to instrumentation(Grant No.EP/P027121/1).
文摘Although machine Learning has demonstrated exceptional applicability in thermographic inspection,precise defect reconstruction is still challenging,especially for complex defect profiles with limited defect sample diversity.Thus,this paper proposes a self-enhancement defect reconstruction technique based on cycle-consistent generative adversarial network(Cycle-GAN)that accurately characterises complex defect profiles and generates reliable artificial thermal images for dataset augmentation,enhancing defect characterisation.By using a synthetic dataset from simulation and experiments,the network overcomes the limited samples problem by learning the diversity of complex defects from finite element modelling and obtaining the thermography uncertainty patterns from practical experiments.Then,an iterative strategy with a self-enhancement capability optimises the characterisation accuracy and data generation performance.The designed loss function structure with cycle consistency and identity loss constrains the GAN’s transfer variation to guarantee augmented data quality and defect reconstruction accuracy simultaneously,while the self-enhancement results significantly improve accuracy in thermal images and defect profile reconstruction.The experimental results demonstrate the feasibility of the proposed method by attaining high accuracy with optimal loss norm for defect profile reconstruction with a Recall score over 0.92.The scalability investigation of different materials and defect types is also discussed,highlighting its capability for diverse thermography quantification and automated inspection scenarios.
基金supported by the National Key Research and Development Program of China(Fund for Young Scientists 2021YFC2900400)Chongqing Outstanding Youth Science Fund project(CSTB2023NSCQ-JQX0027).
文摘Understanding rock behavior is crucial in mine geotechnical engineering to ensure construction efficiency,mitigate rock-related hazards,and promote environmental sustainability.Coda Wave Interferometry(CWI),a non-destructive ultrasonic testing method,has been widely employed to assess micro-damage evolution in rocks induced by perturbations in scatterer position,velocity,or source location due to its exceptional sensitivity.However,challenges persist in evaluating cross-scale rock behavior influenced by nonlinear deformation and multi-field interactions under multiple coupled perturbations.A comprehensive review of the perturbation factors affecting rock damage evolution and potential failure mechanisms is essential for presenting available knowledge in a more systematic and structured manner.This review provides an in-depth analysis of the CWI technique,encompassing its origins,theoretical framework,and classical data processing methodologies.Additionally,it explores the diverse applications of CWI in assessing rock behavior under various perturbation factors,including temperature variations,fluid infiltration,and stress conditions,with a particular emphasis on nonlinear deformation and multi-field coupling effects.Furthermore,a novel method for calculating relative velocity changes in coda waves is introduced,enabling a more precise characterization of the entire rock failure process.The study also proposes a cutting-edge concept of ultra-early and refined monitoring and warning technology for mine rock disasters,leveraging the advancements in CWI.Finally,the review highlights the potential future developments of CWI in high-level intelligent mining scenarios,particularly its integration with ambient noise interferometry and microseismic coda wave analysis.This work serves as a valuable reference,contributing to the refinement of CWI applications for assessing complex rock behavior and enhancing the accuracy of rock disaster prediction and early warning systems.
基金Independent Scientific Research Project for Graduate Students of Beijing University of Chinese Medicine(2023),No.ZJKT2023020.
文摘BACKGROUND Previous studies have validated the efficacy of both magnetic compression and surgical techniques in creating rabbit tracheoesophageal fistula(TEF)models.Magnetic compression achieves a 100%success rate but requires more time,while surgery,though less frequently successful,offers rapid model establishment and technical maturity in larger animal models.AIM To determine the optimal approach for rabbit disease modeling and refine the process.METHODS TEF models were created in 12 rabbits using both the modified magnetic compression technique and surgery.Comparisons of the time to model establishment,success rate,food and water intake,weight changes,activity levels,bronchoscopy findings,white blood cell counts,and biopsies were performed.In response to the failures encountered during modified magnetic compression modeling,we increased the sample size to 15 rabbit models and assessed the repeatability and stability of the models,comparing them with the original magnetic compression technique.RESULTS The modified magnetic compression technique achieved a 66.7%success rate,whereas the success rate of the surgery technique was 33.3%.Surviving surgical rabbits might not meet subsequent experimental requirements due to TEF-related inflammation.In the modified magnetic compression group,one rabbit died,possibly due to magnet corrosion,and another died from tracheal magnet obstruction.Similar events occurred during the second round of modified magnetic compression modeling,with one rabbit possibly succumbing to aggravated lung infection.The operation time of the first round of modified magnetic compression was 3.2±0.6 min,which was significantly reduced to 2.1±0.4 min in the second round,compared to both the first round and that of the original technique.CONCLUSION The modified magnetic compression technique exhibits lower stress responses,a simple procedure,a high success rate,and lower modeling costs,making it a more appropriate choice for constructing TEF models in rabbits.
基金Ministry of Higher Education of Malaysia for funding the project on PEC NDT at IIUM through the research grant FRGS16-059-0558supported by the National Natural Science Foundation of China under research grants 51677187 and 51307172
文摘Pulsed eddy current （PEC） non-destructive test- ing and evaluation （NDT＆E） has been around for some time and it is still attracting extensive attention from researchers around the globe, which can be witnessed through the reports reviewed in this paper. Thanks to its richness of spectral components, various applications of this technique have been proposed and reported in the lit- erature covering both structural integrity inspection and material characterization in various industrial sectors. To support its development and for better understanding of the phenomena around the transient induced eddy currents, attempts for its modelling both analytically and numeri- cally have been made by researchers around the world. This review is an attempt to capture the state-of-the-art development and applications of PEC, especially in the last 15 years and it is not intended to be exhaustive. Future challenges and opportunities for PEC NDT＆E are also presented.
基金the support given by the government and official in Guangnan Countyfunded by[National Natural Science Foundation of China]grant number[41361020,40961031]+3 种基金[Joint Fund of Yunnan Provincial Science and Technology Department and Yunnan University]grant number[2018FY001(-017)][Project of Innovative Talents Cultivation for Graduate Students of Yunnan University]grant number[C176230200][Project of Internationalization and Cultural Inheritance and Innovation of Yunnan University]grant number[C176250202][Science Research Fund of Yunnan Provincial Education Department in 2020:Postgraduate]grant number[2020Y0030]。
文摘The karst mountainous area is an ecologically fragile region with prominent humanland contradictions.The resource-environment carrying capacity(RECC)of this region needs to be further clarified.The development of remote sensing(RS)and geographic information system(GIS)provides data sources and processing platform for RECC monitoring.This study analyzed and established the evaluation index system of RECC by considering particularity in the karst mountainous area of Southwest China;processed multisource RS data(Sentinel-2,Aster-DEM and Landsat-8)to extract the spatial distributions of nine key indexes by GIS techniques(information classification,overlay analysis and raster calculation);proposed the methods of index integration and fuzzy comprehensive evaluation of the RECC by GIS;and took a typical area,Guangnan County in Yunnan Province of China,as an experimental area to explore the effectiveness of the indexes and methods.The results showed that:(1)The important indexes affecting the RECC of karst mountainous area are water resources,tourism resources,position resources,geographical environment and soil erosion environment.(2)Data on cultivated land,construction land,minerals,transportation,water conservancy,ecosystem services,topography,soil erosion and rocky desertification can be obtained from RS data.GIS techniques integrate the information into the RECC results.The data extraction and processing methods are feasible on evaluating RECC.(3)The RECC of Guangnan County was in the mid-carrying level in 2018.The midcarrying and low-carrying levels were the main types,accounting for more than 80.00%of the total study area.The areas with high carrying capacity were mainly distributed in the northern regions of the northwest-southeast line of the county,and other areas have a low carrying capacity comparatively.The coordination between regional resource-environment status and socioeconomic development is the key to improve RECC.This study explores the evaluation index system of RECC in karst mountainous area and the application of multisource RS data and GIS techniques in the comprehensive evaluation.The methods can be applied in related fields to provide suggestions for data/information extraction and integration,and sustainable development.
文摘In recent years, advanced composite structures are used extensively in many industries such as aerospace, aircraft, automobile, pipeline and civil engineering. Reliability and safety are crucial requirements posed by them to the advanced composite structures be- cause of their harsh working conditions. Therefore, as a very important measure, structural health monitoring （SHM） in-service is deft- nitely demanded for ensuring their safe working in-situ. In this paper, fiber Bragg grating （FBG） sensors are surface-mounted on the hoop and in the axial directions of a FRP pressure vessel to monitor the strain status during its pressurization. The experimental results show that the FBG sensors could be used to monitor the strain development and determine the ultimate failure strain of the composite pressure vessel.
文摘In the world,nonalcoholic fatty liver disease(NAFLD)accounts for majority of diffuse hepatic diseases.Notably,substantial liver fat accumulation can trigger and accelerate hepatic fibrosis,thus contributing to disease progression.Moreover,the presence of NAFLD not only puts adverse influences for liver but is also associated with an increased risk of type 2 diabetes and cardiovascular diseases.Therefore,early detection and quantified measurement of hepatic fat content are of great importance.Liver biopsy is currently the most accurate method for the evaluation of hepatic steatosis.However,liver biopsy has several limitations,namely,its invasiveness,sampling error,high cost and moderate intraobserver and interobserver reproducibility.Recently,various quantitative imaging techniques have been developed for the diagnosis and quantified measurement of hepatic fat content,including ultrasound-or magnetic resonancebased methods.These quantitative imaging techniques can provide objective continuous metrics associated with liver fat content and be recorded for comparison when patients receive check-ups to evaluate changes in liver fat content,which is useful for longitudinal follow-up.In this review,we introduce several imaging techniques and describe their diagnostic performance for the diagnosis and quantified measurement of hepatic fat content.
基金Sichuan province Science and Technology department( No. 2011GZ0002 and No. 2013HH0059)the university basic scientific research project( No. ZYGX2013J090 ) for funding the work
文摘This paper introduces recent research work in the field of pulsed electromagnetic non-destructive testing/evaluation.These are pulsed eddy current,pulsed magnetic flux leakage and eddy current pulsed thermography.This paper introduces pulsed electromagnetic techniques and their different case studies on defect detection as well as stress characterisation.Experimental tests have been validated and future research plans are discussed.This paper demonstrates pulsed electromagnetic non-destructive testing and evaluation for not only depth information,but also for multiple parameter measurement and multiple integration,which are important for future development.
文摘This article should not be considered as a full review of current methods for non-destructive testing of surface layers. Rather, it is a subjective in this area. However, the article provides some review of the challenges posed by the current state of surface layers treatment techniques on the area of Non-Destructive materials evaluation: enhancement of the sensitivity to the type of defects, increasing resolution to submicron values, the requirement to diagnose the surface layers with depth resolution of properties, diagnosis of multilayer multicomponent surface layers and coatings, treated with concentrated energy.
基金funded by the National Key Research and Development Program of China(No:2020YFC1909900)the National Natural Science Foundation of China(No:51908550)the Scientific Research Project of China Academy of Railway Sciences Group Corporation Limited(No:2021YJ173).
文摘Purpose – This study aims to analyze the factors, evaluation techniques of the durability of existing railwayengineering.Design/methodology/approach – China has built a railway network of over 150,000 km. Ensuring thesafety of the existing railway engineering is of great significance for maintaining normal railway operationorder. However, railway engineering is a strip structure that crosses multiple complex environments. Andrailway engineering will withstand high-frequency impact loads from trains. The above factors have led todifferences in the deterioration characteristics and maintenance strategies of railway engineering compared toconventional concrete structures. Therefore, it is very important to analyze the key factors that affect thedurability of railway structures and propose technologies for durability evaluation.Findings – The factors that affect the durability and reliability of railway engineering are mainly divided intothree categories: material factors, environmental factors and load factors. Among them, material factors alsoinclude influencing factors, such as raw materials, mix proportions and so on. Environmental factors varydepending on the service environment of railway engineering, and the durability and deterioration of concretehave different failure mechanisms. Load factors include static load and train dynamic load. The on-site rapiddetection methods for five common diseases in railway engineering are also proposed in this paper. Thesemethods can quickly evaluate the durability of existing railway engineering concrete.Originality/value – The research can provide some new evaluation techniques and methods for thedurability of existing railway engineering.
基金Supported by Ningbo Municipal Natural Science Foundation of China (Grant No.2014A610063)
文摘Nondestructive techniques for appraising gas metal arc welding（GMAW） faults plays a very important role in on-line quality controllability and prediction of the GMAW process. On-line welding quality controllability and prediction have several disadvantages such as high cost, low efficiency, complication and greatly being affected by the environment. An enhanced, efficient evaluation technique for evaluating welding faults based on Mahalanobis distance（MD） and normal distribution is presented. In addition, a new piece of equipment, designated the weld quality tester（WQT）, is developed based on the proposed evaluation technique. MD is superior to other multidimensional distances such as Euclidean distance because the covariance matrix used for calculating MD takes into account correlations in the data and scaling. The values of MD obtained from welding current and arc voltage are assumed to follow a normal distribution. The normal distribution has two parameters： the meanm and standard deviations of the data. In the proposed evaluation technique used by the WQT, values of MD located in the range from zero tom＋3s are regarded as “good”. Two experiments which involve changing the flow of shielding gas and smearing paint on the surface of the substrate are conducted in order to verify the sensitivity of the proposed evaluation technique and the feasibility of using WQT. The experimental results demonstrate the usefulness of the WQT for evaluating welding quality. The proposed technique can be applied to implement the on-line welding quality controllability and prediction, which is of great importance to design some novel equipment for weld quality detection.
基金This Investigation receivod financial support from the UNDP/World Bank/WHO Specal Programne for Rosearch and Trainng in Tropical Discascs(TDR)UNDP/World Bank/WHO/TDR提供基金
文摘The QBC techmique in diagnosing vivax malaria was compared with that of the Giemsa stained thick smear under field conditions in Sifang Village.Junlian County,Sichuan Province,China.Blood samples were collected from 161 volunteer villagers.Each sample was examined with both the QBC and Giemsa techniques.Each stained Giemsa thick smear(GTS)was prepared by spreading 10ul blood over an appropriate area on a slide and examined for 300 oil immersion fields,and each QBC tube was observed for 5 min.before considering a sample to be negative.Results showed that 34 blood samples were positive for vivax malaria and 127 were negative by GTS,whereas,there were 32 positives and 129 negatives by QBC.Taking GTS as standard,the sensjtivityand specificity of the QBC technique were 79.41%and 96.06%respectively,and the concordancewas 92.55%.Distributions of different developmental stages of P.raraz parasites in the centrifuged QBC tubes were cbserved and recorded,and the results revealed that all stages except schizonts,could be found in the lower part of the platelet zone,or the interphase between the monocyte and theplatelet layers,especially the ring forms.
基金Project supported by the Scientific Research&Technical Development Project of PetroChina Company Limited“Research and application of key technologies for geology and gas reservoir engineering of underground gas storage”(No.2015E-400201).
文摘Whole-life-cycle integrity management of underground gas storages(UGSs)has been an important link to ensure its long-term safe and efficient operation.At present,the integrity of UGSs in oil/gasfields and its evaluation techniques focus on surface facilities and injection/withdrawal wells,but its geological integrity lacks clear definition and evaluation object and systematic evaluation techniques.In this paper,relevant research achievements werefirstly summarized.Then,the concept of geological integrity with the gas-storage geological body as the evaluation object was put forward,and the evaluation system for the geological integrity of such UGSs was established.Finally,UGS geological integrity evaluation was carried out with the Hutubi Underground Gas Storage in Xinjiang as an example.And the following research results were obtained.First,UGS geological integrity is defined as the integrity degree of each component of a gas-storage geological body to meet operation requirements and fulfill seasonal and emergency peak shaving safely and economically during the operation of a UGS.Its connotation is that reservoir of geological body,caprock,fault and trap can supply the customers with gas continuously and stably and ensure the safe operation of the UGS in its service life.And its core lies in keeping the reliability,safety and economy of natural gas storage in the service life of a UGS.Second,the geological integrity evaluation system is composed of four evaluation techniques,including trap effectiveness,caprock integrity,fault stability and reservoir stability.Third,the evaluation results show that the Hutubi Underground Gas Storage has the potential of peak-shaving capacity enhancement by increasing the maximum operation pressure.In conclusion,the establishment of the geological integrity evaluation system for such UGSs improves the UGS integrity evaluation technique system and plays an instructive and practical role in ensuring the long-term safe and efficient operation of UGSs,increasing the maximum operation pressure and improving the peak shaving capacity.
文摘A non invasive ultrasonic method is used to detect whether or not the frozen fish has suffered a partial or total accidental thawing. The time of flight and the peak to peak amplitude of the ultrasonic signals backscattered by fish are recorded during thawing. The comparison of the evolution curves and images corresponding to first and second thawing shows indicators of accidental thawing. The monitoring of thawing process showed that its assessment can be reduced to the measurement of the water content lost by fish. The attempt to replace the original water lost by fish in first thawing is analyzed. The influence of the transducer frequency on fish thawing evaluation is tested.
文摘Introduction The use of supercritical fluids such as supercritical CO<sub>2</sub>（scCO<sub>2</sub>） has provided a ’clean’ and effective alternative to traditional methods of protein delivery systems.Here。
文摘How＇s the effect of technical import actually？ The latter stage evaluation to technique import project is necessary to get the answer. Therefore, the latter stage evaluation to technique import project is not equal to the latter stage evaluation to general construction projects, it doesn＇t emphasize particularly on its economic profits but the performance of the digest, generalization, improvement and redevelopment of the imported technique.
基金supported by the National Natural Science Foundation of China(Grant No.52275512).
文摘Composite materials are increasingly used in the aerospace and automotive industries due to their high strength-toweight ratio and fatigue resistance.These structures may develop internal defects during manufacturing or service,compromising their integrity and safety.Thus,non-destructive defect detection is critical during production to ensure safety and reliability.This study explores the application of terahertz time-domain spectroscopy(THz-TDS)for detecting damage in different glass fiber-reinforced polymer(GFRP)manufacturing processes.A cross-correlation-based impulse response function extraction algorithm and image enhancement method are proposed.The method targets both deep and minor defects in GFRP,leveraging the correlation between the terahertz reference signal and the time-domain detection signal to extract the terahertz impulse response function via a one-dimensional iterative deconvolution algorithm.Testing on samples with pre-fabricated delamination,three-point bending damage,and drilled damage demonstrated the method’s efficacy in extracting impulse response functions of delamination defects,which aids in defect localization and improved image representation.In the THz imaging analysis of GFRP manufacturing process damage,signal alignment,windowing,and morphology positioning techniques were applied based on the extracted impulse response functions.The proposed method significantly improved the quality of THz images for defect detection in GFRP,as demonstrated by objective evaluations and comparisons.These advancements provide a robust and effective tool for the non-destructive evaluation of composite materials.
文摘To explore the value of helical CT volume rendering technique (VRT) in post-operative evaluation of screw fixation of axis fractures.Methods There were 21 cases of screw fixation of axis fractures between February 2002 and May 2004 in the study including six cases with fractures on axis body,five on odontoid process and 10 on axis body and odontoid process.All cases received X-ray plain film,helical CT scanning,multi-planar reformatting(MPR) and VRT.Results Screw fixation through axis body and massa lateralis atlantis was performed in 10 cases and that through axis body and odontoid process in 11.VRT could clearly display full aperture of screw orbit,location of screw and angle of fixation and hence was superior to X-ray plain film and MPR.Multi-angle VRT displayed asymmetrical space of odontoid process and massa lateralis atlantis in four cases and medial deviation of 2～5 mm of half screw in screw fixation through axis body and massa lateralis atlantis in six.Conclusion VRT can eliminate false shadow of fixation screw,clearly display full aperture of screw orbit and hence supply improtant imaging evidence for post-operative evaluation of screw fixation of axis fractures.7 refs,1 fig,1 tab.
基金the Portuguese Fundacao para a Ciência e a Tecnologia (FCT, I.P.) for its financial support via the project PEst-OE/EME/UI0667/2014Project Hi2TRUST, (Refa3335), supported by Fundo Europeu de Desenvolvimento Regional (FEDER)Programa Operacional Regional de Lisboa (Lisb@2020 and Portugal2020)
文摘The use of non-destructive evaluation(NDE) techniques for assessing microstructural changes in processed materials is of particular importance as it can be used to assess, qualitatively, the integrity of any material/structure. Among the several NDE techniques available, electrical conductivity measurements using eddy currents attract great attention owing to its simplicity and reliability. In this work, the electrical conductivity profiles of friction stir processed Ti6Al4 V, Cu, Pb, S355 steel and gas tungsten arc welded AISI 304 stainless steel were determined through eddy currents and four-point probe. In parallel, hardness measurements were also performed. The profiles matched well with the optical macrographs of the materials: while entering in the processed region a variation in both profiles was always observed. One particular advantage of electrical conductivity profiles over hardness was evident: it provides a better resolution of the microstructural alterations in the processed materials. Moreover, when thermomechanical processing induces microstructural changes that modify the magnetic properties of a material,eddy currents testing can be used to qualitatively determine the phase fraction in a given region of the material. A qualitative relation between electrical conductivity measurements and hardness is observed.
