Yang E.C.,Scottish Association for Marine Science |
Yang E.C.,Korea Advanced Institute of Science and Technology |
Peters A.F.,Santec Systems, Inc. |
Kawai H.,Kobe University |
And 9 more authors.
Journal of Phycology | Year: 2014
The phylogeny of ligulate and sulfuric-acid containing species of Desmarestia, occurring worldwide from polar to temperate regions, was revised using a multigenic and polyphasic approach. Sequence data, gametophyte characteristics, and sporophyte morphology support reducing a total of 16 taxa to four different species. (1) D. herbacea, containing broad-bladed and highly branched forms, has dioecious gametophytes. The three other species have monoecious gametophytes: (2) D. ligulata which is profusely branched and, except for one subspecies, narrow-bladed, (3) Japanese ligulate Desmarestia, here described as D. japonica sp. nov., which is morphologically similar to D. ligulata but genetically distant from all other ligulate taxa. This species may have conserved the morphology of original ligulate Desmarestia. (4) D. dudresnayi, including unbranched or little branched broad-bladed taxa. A figure of the holotype of D. dudresnayi, which was lost for decades, was relocated. The taxonomy is complemented by a comparison of internal transcribed spacer and cytochrome c oxidase subunit I (cox1) as potential barcode loci, with cox1 offering good resolution, reflecting species delimitations within the genus Desmarestia. © 2014 Phycological Society of America.
Sandhu J.S.,Santec Systems, Inc. |
Pergantis C.G.,U.S. Army
AIP Conference Proceedings | Year: 2011
The US Army is investigating the use of composite materials to deliver lightweight and more effective armor protection systems to soldiers and other army assets. However, widespread use of such hybrid armor will require a reliable but fast NDE methodology to ensure integrity of these components during manufacturing and while in service. Traditional ultrasonic inspection of such hybrid armor structures may prove to be very effective, but point-by-point ultrasonic scanning is inherently time-consuming and manufacturing slowdowns could develop in high-volume production of such armor systems. In this paper, we report on the application of acoustography for the NDE of hybrid armor structures. Acoustography differs from conventional ultrasonic testing in that test objects are inspected in full field, analogously to real time x-ray imaging. The approach uses a novel, super high resolution large area acousto-optic (AO) sensor, which allows image formation through simple ultrasound shadow casting, analogous to x-ray image formation. This NDE approach offers significant inspection speed advantage over conventional point-by-point ultrasonic scanning procedures and is well-suited for high volume production. We will report initial results on a number of hybrid armor plate specimens employing composite materials that are being investigated by the US Army. Acoustography NDE results will also be verified using other complimentary NDE methods. © 2011 American Institute of Physics.
Pergantis C.G.,U.S. Army |
Green W.H.,U.S. Army |
Brennan R.E.,U.S. Army |
Sandhu J.S.,Santec Systems, Inc.
International SAMPE Technical Conference | Year: 2013
Acoustography is a novel inspection method where X-ray like, full-field ultrasound images are produced almost instantly. Therefore, it holds the potential to provide dramatically faster inspection throughput compared to more mature methods such as single transducer point-by-point ultrasonic scanning and wide-array transducer scanning. In this paper, we will compare Acoustography, phased array and conventional point-by-point ultrasonic inspection methods utilizing standard composite test specimens. A review of the current state-of-the-art in Acoustography for providing through-transmission ultrasonic (TTU) and reflection-mode ultrasonic (RMU) inspection will also be provided. Direct comparisons of the three methods will be made by measuring factors such as detection sensitivity, inspection speed, operator skill level, and cost.
Poudel A.,Southern Illinois University Carbondale |
Shrestha S.S.,Southern Illinois University Carbondale |
Sandhu J.S.,Santec Systems, Inc. |
Chu T.P.,Southern Illinois University Carbondale |
Pergantis C.G.,U.S. Army
Composites Part B: Engineering | Year: 2015
This paper presents the use of a novel through-transmission ultrasonic (TTU) Acoustography non-destructive evaluation (NDE) method to detect foreign object inclusion (FOI) defects in graphite epoxy composite laminates. The study employed three different composite test standards with varied size FOI defects embedded at varying depth within the composite laminates. For validation, Acoustography results were directly compared with conventional immersion TTU testing and infrared thermography (IRT) methods. From results obtained, it was demonstrated that the Signal-to-Noise Ratio (SNR) measurements for Acoustography were more than 6:1 and were in good correlation with immersion TTU and IRT results. The defect sizing ability of TTU Acoustography for FOI defects in graphite epoxy composite laminates were also in strong correlation with immersion TTU and IRT techniques. Finally, for the three laboratory systems employed in this study, typical panel TTU Acoustography inspection time was just about three minutes to scan a 300 mm × 300 mm (11.8″ × 11.8″) area, which was more than three times faster compared to IRT and sixty times faster to conventional immersion TTU C-Scan techniques. This is a very significant finding for the reason that Acoustography is being developed as a faster, more efficient, and affordable alternative to traditional ultrasonic inspection systems for composite manufacturing quality control and quality assurance (QC/QA) and field maintenance of composite structure applications. © 2015 Elsevier Ltd. All rights reserved.
Rodriguez G.L.,Illinois Institute of Technology |
Weber J.,Santec Systems, Inc. |
Sandhu J.S.,Santec Systems, Inc. |
Anastasio M.A.,Washington University in St. Louis
Ultrasonics | Year: 2011
We propose and experimentally demonstrate a new method for complex-valued wavefield retrieval in off-axis acoustic holography. The method involves use of an intensity-sensitive acousto-optic (AO) sensor, optimized for use at 3.3 MHz, to record the acoustic hologram and a computational method for reconstruction of the object wavefield. The proposed method may circumvent limitations of conventional implementations of acoustic holography and may facilitate the development of acoustic-holography-based biomedical imaging methods. © 2011 Elsevier B.V. All rights reserved.
Santec Systems, Inc. | Date: 2014-08-21
Plumbing fixtures and fittings, namely, faucets, tubs for bathing and shower, toilets, toilet bowls, toilet tanks, toilet tank levers, urinals, bidets, sinks, strainers for water lines, traps, whirlpools, spas with units providing a massaging effect by emitting a stream of water and pumps, inlets and suction fittings therefor, valves, tub-waste assemblies, shower and tub fixtures, namely, shower heads and hand-held showers, electric hot air hand dryers, dehumidifiers, and aerators for attachment to faucets, hydromassage products, namely, bathtubs with hydromassage units, combination shower and bathtubs with hydromassage units, spas with hydromassage units, tubs with hydromassage units, and water pumps, inlets and suction fittings for hydromassage units. Bath and shower accessories, namely, wash basins, toilet paper holders, soap dishes, towel rings, racks and bars, tumbler and toothbrush holders, wall-mounted handrails for the bathroom, cabinet and drawer knobs made of porcelain, ceramic or glass, decorative metal plates, and soap dispensers.
Agency: Department of Defense | Branch: Navy | Program: STTR | Phase: Phase I | Award Amount: 79.90K | Year: 2013
This research work aims to demonstrate the feasibility of applying a novel Acoustography technique for the semi-quantitative evaluation of bond shear strength and assessment of adhesive bond quality in airframe sandwich structures. The proposed approach will utilize thermal and mechanical excitation methods to separate the weak/kissing bonds in the adhesively bonded test coupons. Finite element analysis (FEA) will be conducted to design optimal thermal and mechanical excitation sources and to properly model the effects of disbonds in sandwich interface. Coupons consisting of composite epoxy panels bonded to a Ti-alloy, fabricated with predefined phantom disbond defects, shall be the primary focus of this study. A correlation between acoustography results for predicted bond quality in a range of appropriately flawed test specimens (initially fabricated and aged conditions) and the results of shear testing of the flawed specimens will be drawn. In addition, microstructure evaluation of the bonded samples will also be carried out. The proposed method will be portable, easy to use, and will possess the ability to conduct close-to-the-edge and round curvature inspection. In addition, this method will be more reliable for detecting weak/kissing bonds so as to enhance the reliability and reduce the costs during manufacturing and in-service operations.
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 115.25K | Year: 2010
DESCRIPTION (provided by applicant): The objective of this project is to use a 2D area detector called Acousto-Optic (AO) sensor to provide an acoustic output monitoring method for HIFU transducers, where the need for two separate methods, radiation force balance and hydrophone scanning, is circumvented. The AO sensor provides an instant 2D image of the radiated HIFU field, which currently requires the very slow point-by-point scanning of a needle hydrophone by a trained operator. Unlike the radiation force balance, the AO sensor provides a direct measure of the acoustic intensity as opposed to just total power. Successful completion of this work will provide a superior method for monitoring acoustic output HIFU transducers, which is critical for ensuring correct ultrasound dose delivery by the HIFU transducer for effective cancer treatment and minimizing collateral damage to healthy tissue. PUBLIC HEALTH RELEVANCE: The successful development of the proposed AO sensor based acoustic output monitoring device could enable routine, on-site assessment of HIFU transducer performance, which is imperative to insure correct dose delivery for HIFU cancer treatment. Current practice of using a combination of hydrophone and radiation force balance methods to establish HIFU transducer output are laboratory based, and do not lend themselves for on-site assessment of HIFU transducers.
PubMed | Santec Systems, Inc. and University of Chicago
Type: Journal Article | Journal: Medical physics | Year: 2016
To characterize the dynamic response of a novel acousto-optic (AO) liquid crystal detector for high-resolution transmission ultrasound breast imaging. Transient and steady-state lesion contrast were investigated to identify optimal transducer settings for our prototype imaging system consistent with the FDA limits of 1 W/cmWe have developed a full-field transmission ultrasound breast imaging system that uses monochromatic plane-wave illumination to acquire projection images of the compressed breast. The acoustic intensity transmitted through the breast is converted into a visual image by a proprietary liquid crystal detector operating on the basis of the AO effect. The dynamic response of the AO detector in the absence of an imaged breast was recorded by a CCD camera as a function of the acoustic field intensity and the detector exposure time. Additionally, a stereotactic needle biopsy breast phantom was used to investigate the change in opaque lesion contrast with increasing exposure time for a range of incident acoustic field intensities.Using transducer voltages between 0.3 V and 0.8 V and exposure times of 3 minutes, a unique one-to-one mapping of incident acoustic intensity to steady-state optical brightness in the AO detector was observed. A transfer curve mapping acoustic intensity to steady-state optical brightness shows a high-contrast region analogous to the linear portion of the Hurter-Driffield curves of radiography. Using transducer voltages between 1 V and 1.75 V and exposure times of 90 s, the lesion contrast study demonstrated increasing lesion contrast with increasing breast exposure time and acoustic field intensity. Lesion-to-background contrast on the order of 0.80 was observed.Maximal lesion contrast in our prototype system can be obtained using the highest acoustic field intensity and the longest breast exposure time allowable under FDA standards. Department of Defense (DOD) Breast Cancer Research Program IDEA Award W81XWH-11-1-0332; National Institutes of Health (NIH) Grant T32 EB002103-21 from the National Institute of Biomedical Imaging and Bioengineering (NIBIB).
PubMed | Santec Systems, Inc. and University of Chicago
Type: Journal Article | Journal: Medical physics | Year: 2017
To investigate the feasibility of malignant lesion detection during routine breast cancer screening using an acousto-optic (AO) transmission ultrasound imaging system, particularly in premenopausal women with high breast density.A full-field, single-projection ultrasound imaging system was developed that uses a high-resolution AO detector to convert the acoustic intensity transmitted through the compressed breast into a visual image by virtue of the AO effect in nematic liquid crystals. In this work, a comprehensive system model was proposed to describe the AO imaging process, including the generation of the incident acoustic field by the transducer, the propagation of the field through the breast tissue, and the conversion of the transmitted acoustic field intensity into a visual image. Validation of the imaging model was achieved through comparison of actual AO breast phantom images with simulated images based on the proposed model. Malignant lesion detectability studies were subsequently performed in simulation using homogeneous and heterogeneous numerical breast phantoms.Comparison of actual AO breast phantom images with simulated images based on the proposed system model showed strong agreement, with an RMSE less than 4%. Lesion detectability studies using homogeneous numerical breast phantoms demonstrated excellent visibility for breast lesions as small as 0.5 cm and source frequencies on the order of 4 MHz. Though lesion detectability proved immune to spatial variations in mass density (2%) and attenuation (15%) in the breast parenchyma, minor variations in parenchymal sound speed (1.3%) resulted in substantial refraction artifacts that compromised the diagnostic utility of the prototype system.Differences in acoustic absorption may overcome refraction and enhance lesion visibility at conventional breast ultrasound frequencies (10 to 15 MHz). However, provided the FDA limit on the incident acoustic intensity (1 W/cm