- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Nondestructive Testing for Archaeology and Cultural Heritage (A Practical Guide and New Perspectives) || Nondestructive Testing Technologies for Cultural Heritage: Overview
摘要： In this chapter, the most used NDT geophysical technologies applied in the field of preventive archaeology and in the analysis of monumental heritage will be considered. Starting from the current state of the art, we will examine: Ground-Penetrating Radar (GPR), electrical active (Electrical Resistivity Tomography—ERT; induced polarization—IP) and passive (Self-Potential—SP), and seismic sonic an ultrasonic methods. Here some important theoretical aspect will be explained as simply as possible, also using practical examples.
关键词： Monumental Heritage,Preventive Archaeology,Induced Polarization,Electrical Resistivity Tomography,Geophysical Technologies,Seismic Sonic,Self-Potential,Ground-Penetrating Radar,Nondestructive Testing,Ultrasonic Methods
更新于2025-09-09 09:28:46
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Reliability assessment of pulsed thermography and ultrasonic testing for impact damage of CFRP panels
摘要： In order to quantitatively compare the reliability of pulsed thermography and ultrasonic testing techniques, a set of thirty-five Carbon Fiber Reinforced Plastic (CFRP) composite panels with impact damages are inspected by pulsed thermography and ultrasonic C-scan. The comparative experimental results and Probability of Detection (PoD) analysis results are presented. The quantitative comparison shows that pulsed thermography testing has smaller defect size at 90% PoD with 95% confidence level, i.e. a90/95 values than ultrasonic testing for the parameters and setup used in the inspections of these thirty-five CFRP composite panels.
关键词： Probability of detection,Ultrasonic testing,CFRP,Impact damage,Thermography
更新于2025-09-09 09:28:46
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[IEEE 2018 International Conference on Advances in Computing, Communications and Informatics (ICACCI) - Bangalore, India (2018.9.19-2018.9.22)] 2018 International Conference on Advances in Computing, Communications and Informatics (ICACCI) - FPGA based Ultrasonic thickness measuring device
摘要： This paper aims at the development of ultrasound based thickness measurement device. A Spartan 6 FPGA from Xilinx has been used in the hardware design along with external parallel Analog to Digital and digital to Analog converter. The device is interfaced with a PC or laptop through USB cable. A measurement and control software is developed using MATLAB for conceptual level and final Graphical User Interface has been developed in .NET to transfer different user defined control parameters to the hardware and receive the captured signal. Ultrasonic probes are used to generate and receive physical sound wave in pulse-echo mode. Time of flight (ToF) based calculations are used for deriving the subject dimension.
关键词： ADC Module,Contact Transducer,DAC Module,NDT,Ultrasonic testing,Spartan XC6SLX9 FPGA
更新于2025-09-09 09:28:46
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An ultrasonic sensor composed of a fiber Bragg grating with an air bubble for underwater object detection
摘要： We present and experimentally demonstrate a novel optical fiber ultrasonic sensor composed of a fiber Bragg grating (FBG) with an air bubble for underwater object detection. The air bubble is formed by splicing etched FBG and single mode fiber (SMF) with taper-shaped holes. And because of the corrosive action, the diameters of FBG and SMF reduces from 125 μm to dozens of micrometers, which will be conducive to improving the sensor's performances. The experiment results indicate that the sensor has high voltage responses of 6.3 V and 7.1 V to the continuous and pulse ultrasonic wave (UW) at 1 MHz and could be used for underwater objects imaging with high signal-to-noise ratio (SNR). Subsequently, the environmental temperature will not influence ultrasonic measurements using the sensor on account of the low temperature sensitivity of 19.5 pm/°C.
关键词： Ultrasonic sensor,Fibre Bragg grating,Fibre-optic sensor,Underwater object detection
更新于2025-09-09 09:28:46
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Fluorescent Metal-Semiconductor Hybrid Structures by Ultrasound-Assisted In-Situ Growth of Gold Nanoparticles on Silica-Coated CdSe-Dot/CdS-Rod Nanocrystals
摘要： Gold nanocrystals (AuNCs) were grown on the surface of silica coated CdSe-dot/CdS-rod core/shell nanocrystals by reduction of Au3+ ions in polyethylene glycol under ultrasonic irradiation. The polyethylene glycol not only prevents the penetration of gold ions or precursor molecules into the silica shell, but it also acts as the reducing agent for Au3+ ions. The silica shell’s surface promotes the heterogeneous nucleation of gold nanocrystals, while the ultrasonic irradiation accelerates and enhances the gold nucleation on the silica surface, and ensures the formation of AuNCs with a relatively narrow size distribution. The plasmon-exciton interaction in these metal-semiconductor hybrid systems leads to decreased fluorescence lifetimes and strongly reduced fluorescence blinking of individual hybrid structures.
关键词： ultrasonic irradiation,Gold nanocrystals,CdSe-dot/CdS-rod nanocrystals,plasmon-exciton interaction,polyethylene glycol
更新于2025-09-09 09:28:46
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[IEEE ICASSP 2018 - 2018 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) - Calgary, AB (2018.4.15-2018.4.20)] 2018 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) - Real-Time Total Focusing Method for Ultrasonic Imaging of Multilayered Object
摘要： In imaging of multilayered object, total focusing method (TFM) combined with ray-tracing appeals to numerous researchers because of its superior image quality. But lots of iterative computation to calculate the incident points greatly increases its processing time. Based on line scan-conversion algorithm and Snell’s principle, this paper proposes an efficient method to calculate the incident point. By dividing the image area into multiple regions, the time-consuming iterative calculation of point of incidence (POI) is eliminated. After introducing this method into TFM, the time complexity of Region-Division (RD) TFM is reduced by one order of magnitude. The simulation experiments validate that the imaging speed of RD-TFM is improved dozens of times compared to traditional TFM with ray-tracing. Besides, RD-TFM applies to multilayered objects with both planar and non-planar interface.
关键词： Ultrasonic phased array,Multi-layered object,Full matrix capture,Total focusing method
更新于2025-09-09 09:28:46
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Hardness of polycrystalline SiO <sub/>2</sub> coesite
摘要： We measured elastic moduli and hardness of polycrystalline SiO2 coesite. Translucent polycrystalline bulk coesite with a grain size of about 10 micrometers was fabricated at 8 GPa and 1600°C using a Kawai-type multi-anvil apparatus. The obtained bulk and shear moduli are 94(1) GPa and 60.2(3) GPa, respectively. The resulting Vickers and Knoop hardness values are 10.9(7) GPa and 9.6(4) GPa, respectively, at an indentation load of 4.9 N. Coesite is as hard as other four-fold coordinated silica materials such as quartz and densified silica glasses. The hardness values of coesite and the four-fold coordinated silica materials are about one-third of those of six-fold coordinated silica materials, stishovite and seifertite, which are the hardest known oxides.
关键词： coesite,silicates,mechanical properties,elastic properties,ultrasonic,hardness
更新于2025-09-09 09:28:46
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[ASME ASME 2018 Conference on Smart Materials, Adaptive Structures and Intelligent Systems - San Antonio, Texas, USA (Monday 10 September 2018)] Volume 1: Development and Characterization of Multifunctional Materials; Modeling, Simulation, and Control of Adaptive Systems; Integrated System Design and Implementation - Ultrasonic Piezoelectric Atomizers: Electromechanical Modeling and Performance Testing
摘要： Ultrasonic atomization of bulk liquids has received extensive attention in the past few decades due to the ability to produce controlled droplet sizes, a necessity for many industries such as spray coating and aerosol drug delivery. Despite the increase in attention, one novel application of this technology has been overlooked until recently, and that is the moisture removal capabilities of atomization. The first ever ultrasonic dryer, created by researchers at Oak Ridge National Lab in 2016, applies the mechanisms of atomization to mechanically remove moisture from clothing. The process utilizes the ultrasonic vibrations created by a piezoelectric transducer in direct contact with a wet fabric to rupture the liquid-vapor boundary of the retained water. Once ruptured, smaller droplets are ejected from the bulk liquid and are actively removed from the fabric pores. The mechanisms of droplet ejection from this event are related to both capillary waves forming on the liquid surface (Capillary Wave Theory), as well as the implosion of cavitation bubbles formed from the hydraulic shocks propagating from the transducer (Cavitation Theory). In this work, we present an analytical model for predicting the moisture removal rate of a wet fabric exposed to ultrasonic vibrations, and connect the atomization events to a global variable, acceleration, in order to decouple the relationship between the transducer and applied voltage. The acceleration governing atomization is predicted using a verified numerical model. The numerical model is shown to assist in developing ultrasonic drying by means of efficiently evaluating transducer design changes.
关键词： moisture removal,cavitation theory,piezoelectric transducer,capillary wave theory,Ultrasonic atomization
更新于2025-09-09 09:28:46
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Investigation of hole quality in rotary ultrasonic drilling of borosilicate glass using RSM
摘要： The present article emphasizes on reducing the edge chipping and taper during rotary ultrasonic drilling of one of the most demanded ceramic glasses “BK-7.” Statistical tools of design of experiments and backing plate were adopted as two distinct approaches to curb the chipping damage. Central composite design has been conjugated with desirability function for framing the design matrix. This investigation also emphasizes to study the effect of process variables—spindle speed, ultrasonic power and feed rate—on the chipping width (CW) and taper (T). After developing the second-order regression models for the CW and T, analysis of variance was used to check the fitness of regression models and recognizing the significant model terms. Then impact of each process parameter was analyzed on responses of interest through 3-D surface plots. The feed rate came forth as the most dominating factor by having maximum influence over the qualitative aspects “CW” and “T” of the drilling process. Interactions of higher rpm and power with lower feed effectively reduced the CW and T. The backing material, employed during main experimentation, also proved its effectiveness to reduce CW when main experiments results were compared to the results of pilot experimentation, which was performed without backing plate. Scanning electron microscope (SEM) was used to analyze the different tool wear modes and microstructure of machined surfaces. Tool weight measurement revealed the dominance of bond fracture and grain fracture during the early stage of the drilling process. Apart from brittle fracture, SEM also affirmed the presence of plastically deformed regions over the machined surfaces. Little deviations between the predicted values and experimental values during the confirmatory tests validated the prediction accuracy of regression models at 95% confidence level.
关键词： Ultrasonic,Wear,Taper,Drilling,Optimization,RSM,Chipping,Desirability
更新于2025-09-04 15:30:14
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Study of the Effect of Ni additive in YBa2Cu3O7-δ Superconducting Composite Employing Ultrasonic Measurement
摘要： A series of superconducting composites (100-x) YBa2Cu3O7-δ + x Ni metal (x = 0, 1, 2.5, 5, 7.5, 10 and 15 wt.%) was prepared by the solid state reaction method. Density and molar volume were determined using the immersion method. X-Rays-Diffraction (XRD) and Scanning Electron Microscope (SEM) characterizations were terminated for structural and microstructural analysis. The results showed the presence of orthorhombic peaks of YBa2Cu3O7-δ (YBCO) in the whole composite samples with different lattice constants and how Ni addition affects the distortions in the orthorhombic unit cell of YBCO. A new technique has been used to measure the ultrasonic wave velocities, longitudinal (VL) and transverse or shear (VS), at 4 MHz ultrasonic frequency at room temperature. The mechanical parameters of the sintered superconductor samples including longitudinal modulus (L), shear modulus (G), Young’s modulus (Y), Poisson’s ratio (σ) and microhardness (H) were investigated from the view point of the porosity and the connectivity between the formed phases. Besides, the Debye temperature (?D) was also determined as a function of Ni additions. The elastic moduli, H and ?D have been improved up to 2.5 wt.% Ni, then a decrease in all data observed with further addition of Ni content. Quantitative analysis has been implemented to obtain more details about the structure of the composite samples, based on orthorhombic phases, the oriented grain size, the porosity and the agglomeration between grains.
关键词： Debye temperature,ultrasonic velocity,porosity,elastic moduli,microhardness
更新于2025-09-04 15:30:14