Acoustic Non-Destructive Testing Technology in Concrete Bridge Inspection and Pile Foundation Detection

This article takes the actual construction project of a certain concrete bridge project as an example to analyze the application of acoustic non-destructive testing technology in its detection.It includes an overview of a certain bridge construction project studied and acoustic non-destructive testing technology and the application of acoustic non-destructive testing technology in actual testing.This analysis hopes to provide some guidelines for acoustic non-destructive testing of modern concrete bridge projects.

Optical techniques in non-destructive detection of wheat quality:A review

Wheat quality detection is essential to ensure the safety ofwheat circulation and storage.The traditional wheat quality detection methods mainly include artificial sensory evaluation and physicochemical index analysis,which are difficult to meet the requirements for high accuracy and efficiency in modern wheat quality detection due to the disadvantages of subjectivity,destruction of sample integrity and low efficiency.With the rapid development of optical technology,various optical-based methods,using near-infrared spectroscopy technology,hyperspectral imaging technology and terahertz,etc.,have been proposed for wheat quality detection.These methods have the characteristics of nondestructiveness and high efficiency which make them popular in wheat quality detection in recent years.In this paper,various state-of-the-art optical-based techniques of wheat quality detection are analyzed and summarized in detail.Firstly,the principle and process of common optical non-destructive detection methods for wheat quality are introduced.Then,the optical techniques used in these detection methods are divided into seven categories,and the comparison of these technologies and their advantages and disadvantages are further discussed.It shows that terahertz technology is regarded as the most promising wheat quality detection method compared with other optical detection technologies,because it can not only detect most types of wheat deterioration,but also has higher accuracy and efficiency.Finally,the research of optical technology in wheat quality detection is prospected.The future research of optical technology-based wheat quality detection mainly includes the construction of wheat quality optical detection standardization database,the fusion of multiple optical detection technologies and multiple quality index information,the improvement of the anti-interference of optical technology and the industrialization of optical inspection technology for wheat quality.These studies are of great significance to improve the detection technology of wheat and ensure the storage safety of wheat in the future.

Optical generation,detection and non-destructive testing applications of terahertz waves

Optoelectronic terahertz generation and detection play a key role in the applications of non-destructive testing,which involves different areas such as physics,biological,material science,imaging,explosions detection,astronomy applications,semiconductor technology and superconductiong electronics. In this article,we present a reviewof the principle and performance of typical terahertz sources,detectors and non-destructive testing applications. On this basis,the newdevelopment and trends of terahertz radiation detectors are also discussed.

Multi-Energy Gamma-Ray Attenuations for Non-Destructive Detection of Hazardous Materials

We present a non-destructive method (NDM) to identify minute quantities of high atomic number (Z) elements in containers such as passenger baggage, goods carrying transport trucks, and environmental samples. This method relies on the fact that photon attenuation varies with its energy and properties of the absorbing medium. Low-energy gamma-ray intensity loss is sensitive to the atomic number of the absorbing medium, while that of higher-energies vary with the density of the medium. To verify the usefulness of this feature for NDM, we carried out simultaneous measurements of intensities of multiple gamma rays of energies 81 to 1408 keV emitted by sources 133Ba (half-life = 10.55 y) and 152Eu (half-life = 13.52 y). By this arrangement, we could detect minute quantities of lead and copper in a bulk medium from energy dependent gamma-ray attenuations. It seems that this method will offer a reliable, low-cost, low-maintenance alternative to X-ray or accelerator-based techniques for the NDM of high-Z materials such as mercury, lead, uranium, and transuranic elements etc.

Alcoholism Detection by Wavelet Energy Entropy and Linear Regression Classifier

Alcoholism is an unhealthy lifestyle associated with alcohol dependence.Not only does drinking for a long time leads to poor mental health and loss of self-control,but alcohol seeps into the bloodstream and shortens the lifespan of the body’s internal organs.Alcoholics often think of alcohol as an everyday drink and see it as a way to reduce stress in their lives because they cannot see the damage in their bodies and they believe it does not affect their physical health.As their drinking increases,they become dependent on alcohol and it affects their daily lives.Therefore,it is important to recognize the dangers of alcohol abuse and to stop drinking as soon as possible.To assist physicians in the diagnosis of patients with alcoholism,we provide a novel alcohol detection system by extracting image features of wavelet energy entropy from magnetic resonance imaging(MRI)combined with a linear regression classifier.Compared with the latest method,the 10-fold cross-validation experiment showed excellent results,including sensitivity 91.54±1.47%,specificity 93.66±1.34%,Precision 93.45±1.27%,accuracy 92.61±0.81%,F1 score 92.48±0.83%and MCC 85.26±1.62%.

Fluorescent-Dye Doped Thin-Film Sensors for the Detection of Alcohol Vapors

Fluorescence sensors based on a trifluoroacetophone compound doped in ethyl cellulose (EC) thin films have been developed for the detection of methanol, ethanol, and 2-propanol (isopropanol, PriOH) vapors. Thin-film sensors are prepared with 4-dibutylamino-4’-(trifluoroacetyl)stilbene (Chromoionophore IX or CIX) as the fluorescent dye and its solution in EC was spin-coated onto glass slides. The luminescence intensity of the dye (555 nm) is quenched when exposed to alcohol vapor. Tested in the range of ca. 0 - 1.5?× 104 ppm (wt) for MeOH and EtOH, and ca. 0 - 2.3 × 104 ppm for PriOH, the sensors gave detection limits of 9, 13, 21 ppm and quantification limits of 32, 43, and 70 ppm, respectively. To enhance the sensitivity of the sensors, TiO2 particles have been added to the films to induce Mie scattering, which increases the incident light interaction with the sensing films. The sensors in this work have been designed to work in a multianalyte platform for the simultaneous detection of multiple gas analytes.

Simultaneous Quantification of Carbohydrates, Alcohols, and Toxic Components in a Bio-Based Medium Using Dual-Detection HPLC Analysis

Bio-based media, derived from cellulosic biomass depolymerisation or bioconversion processes, are composed of several chemicals and biochemicals. In this study, the main components of a hemicellulosic-based medium were analyzed using a dual detection HPLC method to separate and determine concentrations of the major monosaccharides (glucose, xylose, and arabinose), alcoholic and acidic components (ethanol, xylitol, and acetic acid) and furanic compounds (furfural and hydroxymethylfurfural (HMF)). The analyses, which employed a single stationary phase (Aminex HPX-87H) and two detection methods, were carried out under isocratic conditions and involved mobile phases consisting of 5 mM sulfuric acid and acetonitrile in different mix ratios from 0 to 0.061 mole fraction of acetonitrile. Based on the analysis run time and the chromatogram quality, the optimum condition was determined for the simultaneous quantification of the components.

A fast and adaptive method for automatic weld defect detection in various real-time X-ray imaging systems

A first and effective method is proposed to detect weld deject adaptively in various Dypes of real-time X-ray images obtained in different conditions. After weld extraction and noise reduction, a proper template of median filter is used to estimate the weld background. After the weld background is subtracted from the original image, an adaptite threshold segmentation algorithm is proposed to obtain the binary image, and then the morphological close and open operation, labeling algorithm and fids＇e alarm eliminating algorithm are applied to pracess the binary image to obtain the defect, ct detection result. At last, a fast realization procedure jbr proposed method is developed. The proposed method is tested in real-time X-ray image,s obtairted in different X-ray imaging sutems. Experiment results show that the proposed method is effective to detect low contrast weld dejects with few .false alarms and is adaptive to various types of real-time X-ray imaging systems.

A novel 4D resolution imaging method for low and medium atomic number objects at the centimeter scale by coincidence detection technique of cosmic-ray muon and its secondary particles

The muon radiography imaging technique for high-atomic-number objects(Z)and large-volume objects via muon transmission imaging and muon multiple scattering imaging remains a popular topic in the field of radiation detection imaging.However,few imaging studies have been reported on low and medium Z objects at the centimeter scale.This paper presents an imaging system that consists of three layers of a position-sensitive detector and four plastic scintillation detectors.It acquires data by coincidence detection technique of cosmic-ray muon and its secondary particles.A 3D imaging algorithm based on the density of the coinciding muon trajectory was developed,and 4D imaging that takes the atomic number dimension into account by considering the secondary particle ratio information was achieved.The resultant reconstructed 3D images could distinguish between a series of cubes with 5-mm-side lengths and 2-mm-intervals.If the imaging time is more than 20 days,this method can distinguish intervals with a width of 1 mm.The 4D images can specify target objects with low,medium,and high Z values.

Current Trends and Perspectives of Detection and Location for Buried Non-Metallic Pipelines

Buried pipelines are an essential component of the urban infrastructure of modern cities.Traditional buried pipes are mainly made of metal materials.With the development of material science and technology in recent years,non-metallic pipes,such as plastic pipes,ceramic pipes,and concrete pipes,are increasingly taking the place of pipes made from metal in various pipeline networks such as water supply,drainage,heat,industry,oil,and gas.The location technologies for the location of the buried metal pipeline have become mature,but detection and location technologies for the non-metallic pipelines are still developing.In this paper,current trends and future perspectives of detection and location of buried non-metallic pipelines are summarized.Initially,this paper reviews and analyzes electromagnetic induction technologies,electromagnetic wave technologies,and other physics-based technologies.It then focuses on acoustic detection and location technologies,and finally introduces emerging technologies.Then the technical characteristics of each detection and location method have been compared,with their strengths and weaknesses identified.The current trends and future perspectives of each buried non-metallic pipeline detection and location technology have also been defined.Finally,some suggestions for the future development of buried non-metallic pipeline detection and location technologies are provided.

Higher-Order Statistics for Automatic Weld Defect Detection

Image processing and image analysis are the main aspects for obtaining information from digital image owing to the fact that this techniques give the desired details in most of the applications generally and Non-Destructive testing specifically. This paper presents a proposed method for the automatic detection of weld defects in radiographic images. Firstly, the radiographic images were enhanced using adaptive histogram equalization and are filtered using mean and wiener filters. Secondly, the welding area is selected from the radiography image. Thirdly, the Cepstral features are extracted from the Higher-Order Spectra (Bispectrum and Trispectrum). Finally, neural networks are used for feature matching. The proposed method is tested using 100 radiographic images in the presence of noise and image blurring. Results show that in spite of time consumption, the proposed method yields best results for the automatic detection of weld defects in radiography images when the features were extracted from the Trispectrum of the image.

Enzymatic detection of ethanol based on H_2O_2-sensitive quantum dots

A rapid and sensitive fluorometric method for the enzymatic detection of ethanol using CdSe/ZnS quantum dots （QDs） is proposed. The photoluminescence of QDs is sensitive to H202. This finding leads to a novel approach for the determination of ethanol using alcohol oxidase （AOx） which, on oxidation of ethanol, produces H202. The method has higher sensitivity, wider analytical range （0.1-8 mmol/L）, and a lower detection limit （0.05 mmol/L）. The relationship between quenching of the photoluminescence of the QDs and the concentration of ethanol is linear.

探究不同基胶对透氢EVAC/聚乙烯醇体系性能的影响

基于氢安全检测需求,本文研制出了一种可透氢气的弹性体材料,本研究以透氢胶体为研究对象,其主要组分为复合硅材料基体和透氢助剂成分,调节乙烯-醋酸乙烯无规共聚物和聚乙烯醇的复配基体及增韧系统;取复合基体(乙烯-醋酸乙烯无规共聚物+聚乙烯醇)为50/50(%)中分别加入弹性体增韧剂马来酸酐接枝三元乙丙橡胶(EPDM-g-MAH)、马来酸酐接枝乙烯-辛烯共聚物(POE-g-MAH)、马来酸酐接枝加氢苯乙烯-丁二烯-苯乙烯共聚物(SEBS-g-MAH)、韧性好模量低的增韧树脂茂金属聚乙烯(mPE)及刚性粒子碳酸钙,探索不同增韧剂体系对透氢体系力学性能的影响。研究结果表明,复合硅胶基体为50/50(%)时性能最优,弹性体增韧明显改善了透氢材料力学性能,其次为mPE,而适当使用刚性粒子也可起到对体系既增强又增韧的作用,本研究成果可为用氢安全提供保障。

Rapid on-line non-destructive detection of the moisture content of corn ear by bioelectrical impedance spectroscopy

Moisture content of corn directly affects its quality and storage time,and the rapid on-line detection of the moisture content of corn ears not threshed or in vivo in the fields is required.Because of the special shape of corn ear,the rapid,low cost and non-destructive bioelectrical impedance measurement is more suitable for its moisture content detection.Using the four-electrode method with the Agilent E4980A precision LCR meter,the electrical impedance spectroscopies of the sweet corn ears and waxy corn ears at different moisture contents were acquired.The frequency range of the detection was from 20 Hz to 2 MHz and to enhance the contact,the attached-type electrodes were wrapped in cotton soaked with 0.1%NaCl solution.The impedance data over the frequency range from 300 Hz to 5 kHz were used to obtain the parameters of the bio-impedance Cole-Cole model.The results showed a good linear correlation(coefficient of determination R2=0.960)between the equivalent parallel resistance R∞of sweet corn ear and the moisture content value determined by standard chemical method.The research proved that the bioelectrical impedance spectroscopy can be used for detecting the moisture content of corn ear.

气相色谱法检测β-蒎烯、诺蒎酮和紫苏醇

采用Rtx@-Wax极性柱(30 m×0.25 mm×0.25μm)的气相色谱同时检测β-蒎烯的加压氧化产物,包括β-蒎烯、诺蒎酮和紫苏醇。结果表明,β-蒎烯、诺蒎酮、紫苏醇的标准曲线分别为y_(1)=541638x_(1)-54935,y_(2)=431452x_(2)-127193和y_(3)=434504x_(3)-149514,相关系数R^(2)>0.999,且分别在2.001~20.014 mg/mL,1.014~10.142 mg/mL和0.983~9.834 mg/mL范围内呈稳定的线性关系;加标回收率分别为99.03%~103.18%,100.43%~101.84%和99.89%~101.72%,RSD分别为0.61%~2.13%,0.75%~3.94%和0.93%~3.06%。测得三者样品RSD分别为0.97%~2.06%,1.45%~2.81%和1.18%~2.93%。该方法快速简单,准确度高,稳定性好,可同时检测β-蒎烯、诺蒎酮和紫苏醇。

基于近红外光谱法的血液酒精浓度检测仪

针对解决呼气式酒精检测仪存在飞沫传播风险的问题,提出了一种基于近红外光谱法的便携式无污染血液酒精浓度检测方案。使用硬件完成信号采集、放大、滤波再放大,利用软件完成卡尔曼滤波、三样条插值法去基等算法获取标准的脉搏波信号在上位机中通过呼气式的测量结果与脉搏波信号的幅值建立数学模型,将数学模型写入单片机实现离线测量。通过实验测试验证数学模型精度。结果表明,其满足相对误差小于10%的精度要求,符合实际使用需求。

醇响应型智能膜的制备及其甲醇检测性能

采用沉淀聚合法制备了不同亲水性的聚N-正丙基丙烯酰胺(PNN)、聚N-异丙基丙烯酰胺(PNI)和聚N-甲基异丙基丙烯酰胺(PNM)微球,通过物理共混和液体诱导相分离(LIPS)结合的方法将它们引入聚偏氟乙烯(PVDF)膜基材,成功制备了可在常温下检测甲醇浓度的醇响应型智能膜.系统探究了微球的温度响应性和醇响应性,以及微球亲水特性对膜微观结构、表面化学成分的影响,并考察了膜在甲醇、乙醇及甲醇-乙醇混合溶液中的响应性能.结果表明,微球亲水性越强,醇响应型智能膜的厚度、孔径和孔隙率也显著增大.添加最亲水PNM微球的智能膜(PVDF/PNM)的膜厚、孔径、孔隙率达到最大值,分别为空白膜的2.4倍、4.7倍和5.9倍.膜的最大渗透率(P_(max))和醇临界响应体积分数受操作温度、醇溶液类型和微球亲水性的影响.PVDF/PNM膜的甲醇和乙醇响应性差异最大,在40℃下的临界甲醇响应体积分数(C_(M))和临界乙醇响应体积分数(C_(E))差值达到6.5%.常温25℃下,随着总醇体积分数为40%的混合溶液中甲醇比例增大,膜渗透率与甲醇体积分数呈现良好的线性关系,可通过渗透率计算得到混合醇溶液中甲醇浓度.上述研究结果为甲醇浓度的便捷检测提供了一种新思路.

变化蜂巢织物基压力传感器的制备及性能研究

为改善织物基柔性压力传感器的灵敏度、响应性和稳定性,通过机织结构设计将微结构引入棉织物中,织造了具有圆顶形微表面结构的变化蜂巢组织织物。以变化蜂巢织物、炭黑(CB)和聚乙烯醇(PVA)为原料,采用浸烘法制备了不同的传感织物。测试了炭黑质量分数与传感器电阻的关系,并对制备的传感器结构形貌和力学传感性能进行表征,探讨其在人体运动监测中的应用。结果表明:在炭黑质量分数为5%时,传感器电阻降至20 kΩ/cm,制备的传感器具有较高的灵敏度,较小的迟滞性,在不同压力和压缩速率条件下均能保持良好的稳定性、重复性及耐用性。认为:制备的传感器可以应用于人体运动监测,包括手指按压、指关节、手腕和肘关节弯曲运动等。

聚二乙炔囊泡用于饮料酒中乙醇的可视化检测

随着人们生活水平的提升,饮料酒的消费逐渐上升,引起了市场监管和更多消费者对其品质和乙醇检测方面的关注。因此开发一种操作简单、检测迅速且结果直观的新型乙醇检测器十分必要。作者设计并制备了用于检测饮料酒中乙醇的聚二乙炔(polydiacetylene,PDA)囊泡,通过饮料酒中乙醇对PDA囊泡结构的扰动和基团的作用,使囊泡由无乙醇存在时的蓝色逐渐转变为有乙醇时的红色,从而检测产品的乙醇体积分数。结果表明,乙醇体积分数为30%~90%时,与PDA囊泡的比色响应(colorimetric response,CR)值具有良好的线性关系,在实际酒样检测中的相对标准偏差为1.45%~2.23%,裸眼识别颜色变化效果较好。此方法具有高效便捷、结果可视化、反应迅速的优点,为饮料酒中乙醇的检测提供了新方法。