1. Articles in category: NDE/NDT

    1-24 of 243 1 2 3 4 ... 9 10 11 »
    1. Nondestructive Analysis of Jingdezhen and Longquan Celadon Wares Excavated from Nanhai No.1 Shipwreck

      Nondestructive Analysis of Jingdezhen and Longquan Celadon Wares Excavated from Nanhai No.1 Shipwreck

      The provenance study of ancient ceramics, as an important part in archaeological field, is the researching focus for researchers in scientific and technological archaeology. At present, the provenance study of ancient ceramics mainly depends on chemical analysis technologies while non-destructive physical structural analysis of ceramic glaze is relatively lacking. Therefore, it is difficult to have a comprehensive understanding of ancient ceramics. Optical coherence tomography (OCT) is an emerging non-destructive imaging technology with a high sensitivity. In this paper, the OCT combined with X-ray fluorescence spectroscopy (XRF) is employed firstly to analyze celadon wares of Jingdezhen and Longquan found in Nanhai ...

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    2. Nondestructive analysis of automotive paints with spectral domain optical coherence tomography

      Nondestructive analysis of automotive paints with spectral domain optical coherence tomography

      We have demonstrated for the first time, to our knowledge, the use of optical coherence tomography (OCT) as an analytical tool for nondestructively characterizing the individual paint layer thickness of multiple layered automotive paints. A graph-based segmentation method was used for automatic analysis of the thickness distribution for the top layers of solid color paints. The thicknesses measured with OCT were in good agreement with the optical microscope and ultrasonic techniques that are the current standard in the automobile industry. Because of its high axial resolution (5.5 μm), the OCT technique was shown to be able to resolve the ...

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      Mentions: Yalin Zheng
    3. Towards in-situ process monitoring in selective laser sintering using optical coherence tomography

      Towards in-situ process monitoring in selective laser sintering using optical coherence tomography

      Selective laser sintering (SLS) enables fast, flexible and cost-efficient production of parts directly from 3D CAD data. However, compared with more established machine tools, there is a marked lack of process monitoring and feedback control of key process variables to optimize production parameters in-situ. We apply optical coherence tomography (OCT) to evaluate components produced by SLS and suggest a route for its application in in-situ process monitoring within the SLS tool for real-time monitoring of the SLS process for assurance, or even dynamic correction of defects during the build. OCT is shown to be a viable technique for evaluation of ...

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    4. Handheld non-contact evaluation of fastener flushness and countersink surface profiles using optical coherence tomography

      Handheld non-contact evaluation of fastener flushness and countersink surface profiles using optical coherence tomography

      We report the use of spectral domain optical coherence tomography (SD-OCT) for non-contact optical evaluation of fastener flushness and countersink surface profile. Using a handheld galvanometer scanner of only 0.5 lb in weight the SD-OCT can perform line scan surface profile measurement of fastener and countersink without demanding accurate scan center alignment. It demonstrates fast measurement of fastener flushness, radius, slant angle, as well as countersink edge radius and surface angle within 90 ms suitable for handheld operation. With the use of a broadband light source at 840 nm center wavelength and 45 nm spectral bandwidth and a lens ...

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    5. Interferometric system based on swept source-optical coherence tomography scheme applied to the measurement of distances of industrial interest

      Interferometric system based on swept source-optical coherence tomography scheme applied to the measurement of distances of industrial interest

      We used an interferometric technique based on typical optical coherence tomography (OCT) schemes for measuring distances of industrial interest. The system employed as a light source a tunable erbium-doped fiber laser of ∼ 20 - pm ∼20-pm bandwidth with a tuning range between 1520 and 1570 nm. It has a sufficiently long coherence length to enable long depth range imaging. A set of fiber Bragg gratings was used as a self-calibration method, which has the advantage of being a passive system that requires no additional electronic devices. The proposed configuration and the coherence length of the laser enlarge the range of maximum ...

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    6. Development of spectral domain optical coherence tomography for pharmaceutical and medical application

      Development of spectral domain optical coherence tomography for pharmaceutical and medical application

      Spectral-domain optical coherence tomography (SD-OCT) is a type of non-destructive imaging technique that is capable of resolving the inner structure of a sample with micrometre spatial resolution. SD-OCT is based on low coherence interferometry. It utilises a spectrometer to grab the spectral interferogram between the back reflected/scattered light from a reference mirror and a sample. The depth profile, which carries the sample inner structure information, is then generated by a data interpolation and Fourier Transform (FT). Functional coating of solid oral dosage forms optimises the release profile of active pharmaceutical ingredient (API) and results in a desirable API absorption ...

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    7. Response of simulated drinking water biofilm mechanical and structural properties to long-term disinfectant exposure

      Response of simulated drinking water biofilm mechanical and structural properties to long-term disinfectant exposure

      Mechanical and structural properties of biofilms influence the accumulation and release of pathogens in drinking water distribution systems (DWDS). Thus, understanding how long-term residual disinfectants exposure affects biofilm mechanical and structural properties is a necessary aspect for pathogen risk assessment and control. In this study, elastic modulus and structure of groundwater biofilms was monitored by atomic force microscopy (AFM) and optical coherence tomography (OCT) during three months of exposure to monochloramine or free chlorine. After the first month of disinfectant exposure, the mean stiffness of monochloramine or free chlorine treated biofilms was 4 to 9 times higher than those before ...

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    8. The Application of Full-Field Optical Coherence Tomography on Evaluating Film Coating of Pharmaceutical Pellets

      The Application of Full-Field Optical Coherence Tomography on Evaluating Film Coating of Pharmaceutical Pellets

      This paper focuses on the application of full-field optical coherence tomography (FF-OCT) imaging on quantifying coating thickness and characterizing coating structures of two layer pharmaceutical pellets. This FF-OCT system used aninexpensive infrared light-emitting diode (LED) as the opticalsource and a commercial high speed complementary metal-oxidesemiconductor (CMOS) camera as the detector. A total volume of700 × 50 × 200 μm3 (x-y-z) were imaged by using the FF-OCTdevice. A high spatial resolution of 4.0 × 5.0 μm2 (axial × lateral)was achieved. In the cross-sectional image the internal structuredetails can be clearly observed and in particular particle-likefeatures can be clearly ...

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    9. A preliminary study on the identification of vehicle paint chip based on optical coherence tomography

      A preliminary study on the identification of vehicle paint chip based on optical coherence tomography

      Vehicle paint chip is a common evidence that plays a significant role in many criminal cases. This paper introduced a novel imaging technology - optical coherence tomography (OCT), which can realize non-invasive, rapid, high-resolution and cross-sectional imaging for the identification of vehicle paint chips. In this paper, a 1310nm swept-source OCT system was adopted to implement the paint imaging. The results show that, compared with conventional spectroscopy and SEM methods, OCT technology can directly obtain the tomographic images of the paints without slicing. In addition, the optical attenuation properties were analyzed to provide a new feature for separating different paint samples ...

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      Mentions: Ning Zhang
    10. Recognition of fabric weave patterns using optical coherence tomography

      Recognition of fabric weave patterns using optical coherence tomography

      Traditional methods involve extracting individual warp or weft yarns from the fabric in order to identify the weave repeat manually. This process can become tedious due to its manual nature. Therefore, automatic methods capable of identifying woven fabric repeat are utilized. These methods in general require complex algorithms and calculations. Optical coherence tomography (OCT) is a nondestructive and noncontact technique that allows high-resolution imaging. This paper describes the application of spectral domain optical coherence tomography imaging technique for identifying woven fabric repeat. We present the OCT scans of fabrics from which the weave matrixes were identified. We conclude that optical ...

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    11. Method and device for nondestructive testing of material health especially in the fillets of a composite part

      Method and device for nondestructive testing of material health especially in the fillets of a composite part

      The disclosure relates to devices for the completely automated detection and characterization of a resin flash in a part consisting of a composite material, the device including an OCT measuring head including an OCT measuring module, a manipulator capable of moving the OCT head in space, a control for the manipulator, and a computer including a memory for acquiring the definition of the geometry of the area to be tested, for recording the measurements, for storing a criterion file, and for performing calculations pertaining to the comparison of the recording with the criterion file. The disclosure also relates to a ...

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    12. Measurement of depth-resolved thermal deformation distribution using phase-contrast spectral optical coherence tomography

      Measurement of depth-resolved thermal deformation distribution using phase-contrast spectral optical coherence tomography

      An updated B-scan method is proposed for measuring the evolution of thermal deformation fields in polymers. In order to measure the distributions of out-of-plane deformation and normal strain field, phase-contrast spectral optical coherence tomography (PC-SOCT) was performed with the depth range and resolution of 4.3 mm and 10.7 μm, respectively, as thermal loads were applied to three different multilayer samples. The relation between temperature and material refractive index was predetermined before the measurement. After accounting for the refractive index, the thermal deformation fields in the polymer were obtained. The measured thermal expansion coefficient of silicone sealant was approximately ...

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    13. Freeform metrology using swept-source optical coherence tomography with custom pupil-relay precision scanning configuration

      Freeform metrology using swept-source optical coherence tomography with custom pupil-relay precision scanning configuration

      The recent advances in the optics manufacturing industry to achieve the capability of fabricating rotationally nonsymmetric optical quality surfaces have considerably stimulated the optical designs with freeform components. This opens up new horizons for novel optical systems with larger fields of view and higher performance, or significantly more compact in volume at equal performance compared to conventional systems. A bottleneck to the broad industrial applications of freeform optics remains the lack of a high performance optical metrology tool capable of measuring significant surface departures and slopes of the parts. To address this issue, we have developed a fiber-based swept-source optical ...

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    14. Polyaniline nanoparticles: potential optical coherence tomography contrast agents

      Polyaniline nanoparticles: potential optical coherence tomography contrast agents

      Polyaniline, an organic conducting polymer, exhibits strong light absorption in the near-infrared region. Herein, the potential of polyaniline nanoparticles as the contrast agents for optical coherence tomography imaging was investigated. Polyaniline nanoparticles were synthesized by a facile chemical oxidative method. The optical coherence tomography images obtained from ex vivo swine liver tissues showed the concentration-dependent contrast effect of polyaniline nanoparticles. Then the nanoagents were applied to in vivo optical coherence tomography imaging of tumor tissues using a xenograft tumor mouse model. The penetration depth of the optical coherence tomography signals from tumors injected with polyaniline nanoparticles was significantly lower than ...

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    15. Investigating biofilm structure developing on carriers from lab-scale moving bed biofilm reactors based on light microscopy and optical coherence tomography

      Investigating biofilm structure developing on carriers from lab-scale moving bed biofilm reactors based on light microscopy and optical coherence tomography

      This study focused on characterizing the structure of biofilms developed on carriers used in lab-scale moving bed biofilm reactors. Both light microscopy (2D) and optical coherence tomography (OCT) were employed to track the biofilm development on carriers of different geometry and under different aeration rates. Biofilm structure was further characterized with respect to average biofilm thickness, biofilm growth velocity, biomass volume, compartment filling degree, surface area, etc. The results showed that carriers with a smaller compartment size stimulated a quick establishment of biofilms. Low aeration rates favored fast development of biofilms. Comparison between the results derived from 2D and 3D ...

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    16. Feature Of The Week 10/18/2015: Characterising Kiwifruit (Actinidia sp.) Near Skin Cellular Structures using Optical Coherence Tomography

      Feature Of The Week 10/18/2015: Characterising Kiwifruit (Actinidia sp.) Near Skin Cellular Structures using Optical Coherence Tomography

      Pre-harvest growing conditions during the development of fruit have impacts on fruit quality at the time of harvest and during storage. These impacts may result in differences in the skin properties of the fruit and some sub-surface cellular structural changes, which have potential effects on postharvest fruit quality and storability. Optical coherence tomography (OCT) is a non-destructive imaging method that enables acquisition of three-dimensional (3D) images of sub-surface structures of semi-transparent and turbid objects. This technology is a potential tool to provide new information about the structural nature of horticulture products.

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    17. Compact Imaging Granted 15th Patent for Miniature, Low-Cost OCT Technology

      Compact Imaging Granted 15th Patent for Miniature, Low-Cost OCT Technology

      Compact Imaging, Inc. (CI), a Silicon Valley technology company developing miniature, low-cost optical sensors for the rapidly growing biometric security, mobile personal health monitoring and non-destructive testing (NDT) markets, today announced that it had been granted an additional US patent. The new patent increases the CI intellectual property (IP) portfolio to 15 US patents and an equal number of pending US and foreign applications. The Company’s IP centers on multiple-reference optical coherence tomography (MRO™), CI’s miniature version of optical coherence tomography (OCT). A well-established, non-invasive, non-ionizing imaging technology, OCT is widely used in clinical diagnostic applications. Compact Imaging ...

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    18. Photonic Imaging with Optical Coherence Tomography for Quality Monitoring in the Poultry Industry: a Preliminary Study

      Photonic Imaging with Optical Coherence Tomography for Quality Monitoring in the Poultry Industry: a Preliminary Study

      A photonic imaging method that gives the possibility to measure egg quality was applied. Since the method is non-contact and non-destructive we believe that this photonic imaging method may be successfully integrated in the automated inspection systems in the poultry industry. The method involves scanning an invisible infrared light beam over the eggshell, allowing to detect possible cracks and reveal information about the structure of the eggshell. The high resolution, high quality measurements obtained through optical coherence tomography (OCT) make it feasible to be utilized as part of an automated inspection system. In this paper we present an OCT scan ...

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    19. Non-destructive cross-sectional imaging of tomato using ultra-high resolution optical coherence tomography

      Non-destructive cross-sectional imaging of tomato using ultra-high resolution optical coherence tomography

      Optical coherence tomography is an optical imaging technique that performs non-destructive cross-sectional imaging of micrometer-scale structures in samples. In this report, we demonstrated the visualization of inner structures in tomato fruits and leaves with ultra-high resolution optical coherence tomography (UHR-OCT) using fiber based laser source with ultra-broadband continuous spectrum around 1.7 μm wavelength. We confirmed that our UHR-OCT system allows us to perform cross-sectional imaging of tomato fruits and leaves at ∼ 2.8 μm axial resolution.

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    20. Characterising kiwifruit (Actinidia sp.) near skin cellular structures using optical coherence tomography

      Characterising kiwifruit (Actinidia sp.) near skin cellular structures using optical coherence tomography

      Pre-harvest growing conditions during the development of fruit have impacts on fruit quality at the time of harvest and during storage. These impacts may result in differences in the skin properties of the fruit and some sub-surface cellular structural changes, which have potential effects on postharvest fruit quality and storability. Optical coherence tomography (OCT) is a non-destructive imaging method that enables acquisition of three-dimensional (3D) images of sub-surface structures of semi-transparent and turbid objects. This technology is a potential tool to provide new information about the structural nature of horticulture products. This work used five commercial kiwifruit cultivars, ‘G3’, ‘G9 ...

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    21. Optical coherence tomography for the in situ three-dimensional visualization and quantification of feed spacer channel fouling in reverse osmosis membrane modules

      Optical coherence tomography for the in situ three-dimensional visualization and quantification of feed spacer channel fouling in reverse osmosis membrane modules

      To understand the (bio)fouling development in membrane modules in more detail, three-dimensional in situ imaging of the feed spacer channel by means of optical coherence tomography (OCT) was applied. The biofilm formation was investigated in membrane fouling simulators (MFS) mimicking the feed spacer channel of spiral wound reverse osmosis membrane modules. To test the capability of OCT for the visualization of feed spacer fouling, river water and effluent of a waste water treatment plant were used as feeds. Additionally, the (bio)fouling characteristics of a wide-meshed and small-meshed feed spacer were tested. 3D OCT datasets were quantified and the ...

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    22. NIR Micro Beam-splitter by Saw-dicing of Glass Substrate for Optical Coherence Tomography

      NIR Micro Beam-splitter by Saw-dicing of Glass Substrate for Optical Coherence Tomography

      This paper reports the fabrication of a near infrared (NIR) micro beam-splitter (MBS) for Optical Coherence Tomography (OCT) applications. The proposed configuration is based on saw-dicing micromachining of glass substrate combined with thin film deposition of a dielectric multilayer. In order to obtain a splitting with horizontal and vertical transmitted/reflected beams, a 45° surface was fabricated with conventional dicing blades. A dielectric multilayer based only in four thin films was optimized for NIR range (800-900 nm) and for a 50/50 non-polarized split ratio. This multilayer is deposited in the 45° micro machined surface. The MBS offers the possibility ...

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    23. Evaluation of selective laser sintering processes by optical coherence tomography

      Evaluation of selective laser sintering processes by optical coherence tomography

      Selective laser sintering (SLS) enables the fast, flexible and cost-efficient production of parts directly from 3D CAD data. Unlike more established machine tools, there is a marked lack of process monitoring and feedback control of key process variables. In-situ analysis techniques permit the emergence of repair techniques, in-process optimization of production parameters, and will also serve to save time and material. In this study, optical coherence tomography (OCT) is used for the first time to evaluate components produced by SLS. Using a Polyamide-PA2200, surface defects are analyzed and the limiting factors associated with the measurement technique are quantified. OCT is ...

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    24. Indentation Measurements to Validate Dynamic Elasticity Imaging Methods

      Indentation Measurements to Validate Dynamic Elasticity Imaging Methods

      We describe macro-indentation techniques for estimating the elastic modulus of soft hydrogels. Our study describes (a) conditions under which quasi-static indentation can validate dynamic shear-wave imaging estimates and (b) how each of these techniques uniquely biases modulus estimates as they couple to the sample geometry. Harmonic shear waves between 25 and 400 Hz were imaged using ultrasonic Doppler and optical coherence tomography methods to estimate shear dispersion. From the shear-wave speed of sound, average elastic moduli of homogeneous samples were estimated. These results are compared directly with macroscopic indentation measurements measured two ways. One set of measurements applied Hertzian theory ...

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    1-24 of 243 1 2 3 4 ... 9 10 11 »
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